TY - CONF AU - Igarashi, S. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Challenges to Higher Beam Power in J-PARC: Achieved Performance and Future Prospects J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - J-PARC is a world leading intensity frontier accelerator facility, consisting of a 400-MeV H⁻ linac, a 3-GeV Rapid Cycling Synchrotron (RCS) and a 30-GeV slow cycling Main Ring synchrotron (MR). The RCS delivered a 500 kW beam (4.2·10¹³ particles per pulse (ppp)) to the Material and Life science experimental Facility (MLF) in April of 2018, The design power of 1 MW will be delivered in the next few years. Construction of a second target station (2TS) of the MLF with beam power upgraded to 1.5 MW is now under discussion. The MR delivers proton beam to a long-baseline neutrino oscillation experiment, T2K, by fast extraction (FX) and to the hadron experimental facility by slow extraction (SX). For the FX, the maximum beam power is 475 kW and 2.5·10¹⁴ ppp, the world highest ppp in synchrotrons, and for the SX 51 kW and 5.5·10¹³ ppp with an extremely high extraction efficiency of 99.5 %. To achieve 1.3 MW beam power for the neutrino experiment, upgrades to allow operation with a higher repetition rate are planned. The talk will review recent progress of J-PARC facility by highlighting technical challenges toward higher beam power together with future prospects. PB - JACoW Publishing CP - Geneva, Switzerland SP - 6 EP - 11 KW - operation KW - resonance KW - extraction KW - experiment KW - proton DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOYPLM1 UR - http://jacow.org/ipac2019/papers/moyplm1.pdf ER - TY - CONF AU - Sue, Y. AU - Futatsukawa, K. AU - Hasegawa, K. AU - Iijima, T. AU - Iinuma, H. AU - Inami, K. AU - Ishida, K. AU - Kawamura, N. AU - Kitamura, R. AU - Kondo, Y. AU - Mibe, T. AU - Miyake, Y. AU - Morishita, T. AU - Nakazawa, Y. AU - Otani, M. AU - Saito, N. AU - Takeuchi, Y. AU - Ushizawa, T. AU - Yamazaki, T. AU - Yasuda, H.Y. AU - Yotsuzuka, M. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - A Bunch Structure Measurement of Muons Accelerated by RFQ Using a Longitudinal Beam-Profile Monitor With High Time Resolution J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - J-PARC E34 experiment intends to measure the anomalous magnetic moment and electric dipole moment of muon precisely by a different way from the previous experiment. In this experiment, a low-emittance muon beam is provided using the muons with the thermal energy and the four-stage linac. The demonstration of the first muon RF acceleration with an RFQ linac was conducted and the transverse profile of the accelerated muons was measured last year. As one of the remaining issues for the beam-diagnostic system, the longitudinal beam profile after the RFQ should be measured to match the profile to the designed acceptance of the subsequent accelerator. For this purpose, the new longitudinal beam monitor using the micro-channel plate is under development. The time resolution aims to be around 30 to 40 ps corresponding to 1 % of a period of an operation frequency of the accelerator, which is 324 MHz. On November 2018, the bunch structure of accelerated muons of 89 keV with the RFQ was measured using this monitor at the J-PARC MLF. The latest analysis result of this measurement will be reported in this poster. PB - JACoW Publishing CP - Geneva, Switzerland SP - 37 EP - 40 KW - rfq KW - experiment KW - linac KW - background KW - electron DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOZZPLM2 UR - http://jacow.org/ipac2019/papers/mozzplm2.pdf ER - TY - CONF AU - El Khechen, D. AU - Oide, K. AU - Zimmermann, F. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Beam-Beam Blowup Issue After Low Emittance Tuning for FCC-ee J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - FCC-ee (Future Circular Collider) is a 100 km electron-positron circular collider with two foreseen experiments, aiming to run at four energies for precision studies of the Z, W, and Higgs boson and the top quark. The FCC-ee is a challenging machine from different points of view. In particular the beam-beam effects are of great importance. For the FCC-ee high-luminosity operation, the beam-beam effects impose profound constraints on the operating point in betatron tune space. In addition, taking into account different sources of machine nonlinearities, a tracking simulation with beam-beam elements revealed a strong beam blowup, especially in the vertical plane. Such a blowup is a potential obstacle to achieving and maintaining a high luminosity; therefore it needs to be carefully studied. In this paper, we present a general overview of simulation results on the FCC-ee beam-beam blowup with realistic machine errors. PB - JACoW Publishing CP - Geneva, Switzerland SP - 112 EP - 115 KW - emittance KW - lattice KW - simulation KW - optics KW - coupling DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPGW019 UR - http://jacow.org/ipac2019/papers/mopgw019.pdf ER - TY - CONF AU - Hirosawa, K. AU - Funakoshi, Y. AU - Koiso, H. AU - Morita, A. AU - Ohmi, K. AU - Ohnishi, Y. AU - Sugimoto, H. AU - Zhou, D. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Analysis and Correction for the Effect of Multipoles with Skewed Errors on IP Beam Dynamics in SuperKEKB J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The beam dynamics at the interaction point (IP) in the accelerators which has the nano-beam scheme like as SuperKEKB is extremely sensitive for skewed error of final focusing magnets (QCS). As proceeding the beta squeezing in the interaction region (IR), the effect of optics aberrations at IP is enhanced. In the SuperKEKB Phase-2 commissioning, there was the problem come from skewed quadrupole fields in IR. The dominant skew parameters ‘‘R" for this problem is very hard to see directly by using beam position monitors, thus it was corrected by scanning R parameters. In the next commissioning Phase-3 which is just before the operation with the Belle II experiment, it is planned that the IP beta squeezing is going forward to design parameters which is smaller than it achieved in Phase-2 by the factor of 4 (for horizontal beta) and 10 (for vertical beta). Hence the effect of skew error will be considerable larger and it is estimated that skew sextupoles will emerge as a serious cause for the aberration from the orbit. This report is the study of analysis and correction results for the effect of QCS skewed errors in the SuperKEKB commissioning. PB - JACoW Publishing CP - Geneva, Switzerland SP - 159 EP - 162 KW - luminosity KW - coupling KW - MMI KW - betatron KW - optics DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPGW031 UR - http://jacow.org/ipac2019/papers/mopgw031.pdf ER - TY - CONF AU - Kobayashi, A. AU - Igarashi, S. AU - Sato, Y. AU - Shimogawa, T. AU - Sugiyama, Y. AU - Toyama, T. AU - Yoshii, M. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Studies on Coherent Multi-Bunch Tune Shifts with Different Bunch Spacing at the J-PARC Main Ring J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - At a high-power proton synchrotron, betatron tune shifts induced by space charge effects cause beam loss which limits the beam intensity. To achieve further high beam intensity at the main ring of the Japan Proton Accelerator Research Complex, precise control of the tune shift is indispensable. When carrying out multi-bunch measurements, we observed that the dependence of the tune shift intensity on the number of bunches follow opposite slope trends for the horizontal and vertical directions. The influence of the bunch spacing was also observed. We report on a simplified tune shift model reconstruction for understanding the origin of these phenomena and present a correction of the tune shifts for reducing beam loss up to 30 %. PB - JACoW Publishing CP - Geneva, Switzerland SP - 167 EP - 170 KW - space-charge KW - proton KW - impedance KW - operation KW - injection DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPGW036 UR - http://jacow.org/ipac2019/papers/mopgw036.pdf ER - TY - CONF AU - Tanaka, O.A. AU - Miyajima, T. AU - Nakamura, N. AU - Obina, T. AU - Shimada, M. AU - Tanimoto, Y. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Collimator’s Impact Into the Transverse Emittance Growth at KEK Compact ERL J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - In high-intensity particle accelerators, unwanted trans-verse and longitudinal wakefields arise when the high-charge particle beam passes through the narrow chambers or locations with small transverse apertures, such as collimator jaws. Transverse wakefields impose a transverse kicks to the beam, changing its shape, and leading to the growth of the transverse emittance. Longitudinal wakes cause the beam energy losses, heating of the narrow chambers etc. In the present study we investigated the collimator’s impact to the beam. Thus, we evaluated the collimator’s wakefields through the CST simulations. We estimated the corresponding transverse kicks and longitudinal wakes. In the summary simulation results were cross-checked with correspondent analytical expressions. PB - JACoW Publishing CP - Geneva, Switzerland SP - 174 EP - 177 KW - wakefield KW - emittance KW - simulation KW - operation KW - FEL DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPGW038 UR - http://jacow.org/ipac2019/papers/mopgw038.pdf ER - TY - CONF AU - Yamamoto, N. AU - Gamelin, A. AU - Nagaoka, R. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Investigation of Longitudinal Beam Dynamics With Harmonic Cavities by Using the Code Mbtrack J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - In diffraction-limited light sources, the study of collective effects is essential. With harmonic cavities (HCs), the ’flat potential condition’ can be achieved, lengthening the bunch by a factor of ~5. However, the effective rf voltage seen by the beam becomes sensitive to both positions and distributions of all bunches, as the beam-induced voltage of both HCs and fundamental cavities (FCs) contribute. In addition, when there are empty buckets, the transient beam loading induces considerable variations of the rf voltage impacting the beam performance*. Here the use of analytical approaches is difficult. Then we introduced the new functions to treat the high-Q resonators driven by either or both of the beams and external generators to the code mbtrack**. Using these features, various operating conditions with arbitrary fill patterns can be studied; coupled bunch instability induced by HOMs of the cavity, Robinson instabilities and general beam dynamics with HCs. The growth rates of the instabilities described above are compared with analytical results. The ring performance with HCs in several fill patterns shall be also reported. PB - JACoW Publishing CP - Geneva, Switzerland SP - 178 EP - 180 KW - cavity KW - impedance KW - operation KW - synchrotron KW - beam-loading DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPGW039 UR - http://jacow.org/ipac2019/papers/mopgw039.pdf ER - TY - CONF AU - Matsuba, S. AU - Harada, K. AU - Katoh, M. AU - Kawase, K. AU - Shimada, K.S. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Design Study of an Electron Storage Ring for the Future Plan of Hiroshima Synchrotron Radiation Center. J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - Hiroshima synchrotron radiation center equips a 700 MeV electron storage ring nicknamed HiSOR. It has been operated for more than 20 years. The emittance of HiSOR is 400 nm, which is larger by one or more orders of magnitude than typical modern synchrotron light sources. Therefore, as the future plan of the facility, a new low emittance storage ring is desired. Several designs have been examined. In the newest version, we have selected the lattice structure similar to ASTRID 2 compact light source in Aarhus University, Denmark. The design goal is the energy of around 500 MeV, the circumference shorter than 50 m and the emittance smaller than 10 nm with straight sections for undulators more than 4. In this conference, we report the latest result from the design study. PB - JACoW Publishing CP - Geneva, Switzerland SP - 200 EP - 202 KW - storage-ring KW - synchrotron KW - radiation KW - emittance KW - synchrotron-radiation DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPGW048 UR - http://jacow.org/ipac2019/papers/mopgw048.pdf ER - TY - CONF AU - Galyamin, S.N. AU - Aryshev, A. AU - Grigoreva, A.A. AU - Tyukhtin, A.V. AU - Vorobev, V.V. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Radiation from a Dielectrically Loaded Waveguide with Open End J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - Open-ended waveguide structures with dielectric loading excited by specially prepared electron bunches are considered as promising candidates for development of contemporary sources of Terahertz (THz) radiation. Despite of the fact that both ordinary vacuum THz devices (e.g., backward wave oscillator) are widely available and other mechanisms for THz generation are discussed, beam driven sources are still extremely attractive due to the extraordinary peak power of THz radiation*. In this report, we study electromagnetic (EM) field produced by a charged particle bunch exiting an open-ended circular waveguide with dielectric filling placed inside collinear vacuum waveguide of a larger radius. Based on the previously developed theory**, we mainly investigate Cherenkov radiation generated penetrated vacuum regions of the structure due to the diffraction mechanism. We pay attention to the case of a train of short bunches resulting in high-order Cherenkov modes excitation. We also develop analytical procedure allowing performing the limiting process to the case of infinite radius of the outer waveguide. PB - JACoW Publishing CP - Geneva, Switzerland SP - 228 EP - 230 KW - GUI KW - vacuum KW - radiation KW - embedded KW - acceleration DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPGW061 UR - http://jacow.org/ipac2019/papers/mopgw061.pdf ER - TY - CONF AU - Korysko, P. AU - Burrows, P. AU - Faus-Golfe, A. AU - Kubo, K. AU - Latina, A. AU - Okugi, T. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Intensity Dependent Effects at ATF2, KEK J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The Accelerator Test Facility 2 (ATF2) at KEK is a prototype for the Final Focus Systems of the future e⁺e⁻ linear colliders, the International Linear Collider (ILC) and the Compact Linear Collider (CLIC). In this paper both simulation and experimental results are presented with special emphasis on intensity-dependent effects. The importance of these effects is shown using the PLACET code and realistic ATF2 machine simulations (including beam jitter, misalignment, wakefield, Beam Based Alignment (BBA) correction, …). The latest experimental results are also presented, in particular the impact of the beam intensity on the beam size at the IP. PB - JACoW Publishing CP - Geneva, Switzerland SP - 308 EP - 311 KW - simulation KW - collider KW - linear-collider KW - wakefield KW - electron DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPGW086 UR - http://jacow.org/ipac2019/papers/mopgw086.pdf ER - TY - CONF AU - Ogur, S. AU - Barnyakov, A.M. AU - Chaikovska, I. AU - Chehab, R. AU - Furukawa, K. AU - Iida, N. AU - Kamitani, T. AU - Levichev, A.E. AU - Martyshkin, P.V. AU - Miyahara, F. AU - Nikiforov, D.A. AU - Oide, K. AU - Ozcan, E.V. AU - Papaphilippou, Y. AU - Polozov, S.M. AU - Rinolfi, L. AU - Yaman, F. AU - Zimmermann, F. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Linac and Damping Ring Designs for the FCC-ee J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - We report the design of the pre-injector chain for the Future Circular e⁺ e⁻ Collider (FCC-ee) system. The electron beam from a low-emittance RF gun is accelerated by an S-band linac up to 6 GeV. A damping ring at 1.54 GeV is required for emittance cooling of the positron beam. The intermediate energy step from the exit of the S-band linac at 6 GeV to the 20 GeV injection energy of the top-up booster can be provided by the modified Super Proton Synchrotron (SPS), serving as a pre-booster ring (PBR). An alternative option to reach 20 GeV energy would be to extend the S-band linac with a C- or X-band linac. An overall cost optimisation will determine the choice of the final configuration. Beam loss and emittance dilution in the linac due to space charge effects, wakefields, and misalignment of accelerator components can be mitigated by RF phasing and orbit steering. Start-to-end simulations examine the beam transport through the linac up to either 6 GeV or 20 GeV. The results indicate large design margins. Simulations of the beam dynamics in the damping ring (DR) demonstrate a sufficiently large momentum acceptance. Effects of intrabeam scattering and electron cloud instability in the DR are also studied. PB - JACoW Publishing CP - Geneva, Switzerland SP - 420 EP - 423 KW - linac KW - emittance KW - positron KW - gun KW - electron DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPMP002 UR - http://jacow.org/ipac2019/papers/mopmp002.pdf ER - TY - CONF AU - Chaikovska, I. AU - Apyan, A. AU - Chehab, R. AU - Enomoto, Y. AU - Faus-Golfe, A. AU - Furukawa, K. AU - Han, Y. AU - Kamitani, T. AU - Martyshkin, P.V. AU - Miyahara, F. AU - Ogur, S. AU - Oide, K. AU - Papaphilippou, Y. AU - Rinolfi, L. AU - Satoh, M. AU - Seimiya, Y. AU - Sievers, P. AU - Suwada, T. AU - Zimmermann, F. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Positron Source for FCC-ee J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The FCC-ee is a high-luminosity, high-precision circular collider to be constructed in a new 100 km tunnel in the Geneva area. The physics case is well established and the FCC-ee operation is foreseen at 91 GeV (Z-pole), 160 GeV (W pair production threshold), 240 GeV (Higgs resonance) and 365 GeV (t-tbar threshold). Due to the large 6D production emittance and important thermal load in the production target, the positron injector, in particular the positron source, is one of the key elements of the FCC-ee, requiring special attention. To ensure high reliability of the positron source, conventional and hybrid targets are currently under study. The final choice of the positron target will be made based on the estimated performances. In this framework, we present a preliminary design of the FCC-ee positron source, with detailed simulation studies of positron production, capture and primary acceleration. PB - JACoW Publishing CP - Geneva, Switzerland SP - 424 EP - 427 KW - positron KW - target KW - linac KW - electron KW - collider DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPMP003 UR - http://jacow.org/ipac2019/papers/mopmp003.pdf ER - TY - CONF AU - Arimoto, Y. AU - DiMarco, J. AU - Egawa, K. AU - Kawamoto, T. AU - Masuzawa, M. AU - Nogiec, J.M. AU - Ohsawa, Y. AU - Ohuchi, N. AU - Ueki, R. AU - Velev, G. AU - Wang, X. AU - Yamaoka, H. AU - Zong, Z.G. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Magnetic Measurement With Single Stretched Wire Method on SuperKEKB Final Focus Quadrupoles J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - Superconducting-final-focus-quadrupole magnet system (QCS) were installed on an interaction region (IR) of SuperKEKB on Feb. 2017. The QCS consists of eight quadrupole magnets and four compensation solenoids; these magnets are contained in the two cryostats and are installed into Belle II detector which generates a solenoid field of 1.5 T. We determined the quadrupole centers with respect to accelerator beam lines with a single stretched wire (SSW) method. Here the results of the magnetic measurement with SSW are presented. PB - JACoW Publishing CP - Geneva, Switzerland SP - 432 EP - 435 KW - solenoid KW - quadrupole KW - detector KW - controls KW - interaction-region DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPMP006 UR - http://jacow.org/ipac2019/papers/mopmp006.pdf ER - TY - CONF AU - Du, B. AU - Liu, N. AU - Matsumoto, T. AU - Michizono, S. AU - Miura, T. AU - Qiu, F. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Design of a Compact Power Distribution System for the ILC J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The Local power distribution system (LPDS) of the In-ternational Linear Collider (ILC) is constructed to transmit RF power from the 10 MW klystron to 39 cavi-ties. Each eight or nine 9-cell cavities is assembled in one cryomodule. The variable hybrid is used to adjust the power dividing ratio due to the different required power of each cavity and the variable phase shifter is used to compensate the phase drift caused by the variable hybrid. More compact LPDS is expected to be integrated on the cryomodule decreasing financial cost. We re-design the shorter variable hybrid with a margin of power ratio of ±25% and phase shifter of total phase range being 35° for compensating hybrid and on-crest searching. Fixed phase shifters are designed to adjust the phase difference between adjacent cavities for beam acceleration. Simu-lated results of total compact LPDS can meet the re-quirements of ILC. PB - JACoW Publishing CP - Geneva, Switzerland SP - 436 EP - 438 KW - cavity KW - cryomodule KW - ECR KW - acceleration KW - collider DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPMP007 UR - http://jacow.org/ipac2019/papers/mopmp007.pdf ER - TY - CONF AU - Kuriki, M. AU - Nagoshi, H. AU - Negishi, K. AU - Okugi, T. AU - Omori, T. AU - Satoh, M. AU - Seimiya, Y. AU - Sumitomo, Y. AU - Takahashi, T. AU - Urakawa, J. AU - Yokoya, K. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Electron Driven Positron Source for International Linear Collider J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - To linear colliders, huge amount of positron has to be provided comparing to ring colliders, because the beam is dumped after the collision. Electron Driven ILC Positron source has been designed as a technical backup of the undulator position source including the beam loading effect, etc. The design of the detail will be presented. To linear colliders, huge amount of positron has to be provided comparing to ring colliders, because the beam is dumped after the collision. Electron Driven ILC Positron source has been designed as a technical backup of the undulator position source including the beam loading effect, etc. The design of the detail will be presented. PB - JACoW Publishing CP - Geneva, Switzerland SP - 439 EP - 441 KW - positron KW - beam-loading KW - linac KW - simulation KW - cavity DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPMP008 UR - http://jacow.org/ipac2019/papers/mopmp008.pdf ER - TY - CONF AU - Kuriki, M. AU - Hayano, H. AU - Jin, X.J. AU - Kashiwagi, S. AU - Konomi, T. AU - Piot, P. AU - Power, J.G. AU - Sakaue, K. AU - Seimiya, Y. AU - Tamura, R. AU - Washio, M. AU - Yamamoto, N. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Effect of Initial Parameters on the Super Flat Beam Generation with the Phase-Space Rotation for Linear Colliders J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - Linear collider is a concept to realize e⁺e⁻ collision beyond the limitation of the ring colliders by the synchrotron radiation. To obtain an enough luminosity, eg. 1.0·10⁺³⁴ cm⁻²sec⁻¹, the beam is focused down to nano-meter size with a high aspect ratio. This super flat beam is useful to improve the luminosity and to compensate the beam-beam effect, eg. Beamstrahlung. In a conventional design, the super-flat beam is produced by radiation damping in a storage ring. We propose to produce this super-flat beam with phase-space rotation techniques. We employ both Round to Flat Beam Transformation and Transverse to Longitudinal Emittance eXchange, the super flat beam can be generated by controlling the space-charge effect which spoiled the performance. We present the RFBT performance with respect to the initial conditions, i.e. beam size, initial emittance, solenoid field (strength and profile), etc. PB - JACoW Publishing CP - Geneva, Switzerland SP - 442 EP - 444 KW - emittance KW - simulation KW - gun KW - collider KW - solenoid DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPMP009 UR - http://jacow.org/ipac2019/papers/mopmp009.pdf ER - TY - CONF AU - Zimmermann, F. AU - Abelleira, J.L. AU - Abramov, A. AU - Amorim, D. AU - Antipov, S.A. AU - Apyan, A. AU - Arsenyev, S. AU - Barranco García, J. AU - Benedikt, M. AU - Bruce, R. AU - Burkart, F. AU - Cai, Y. AU - Crouch, M.P. AU - Cruz Alaniz, E. AU - Fartoukh, S.D. AU - Giovannozzi, M. AU - Goddard, B. AU - Guillermo Cantón, G. AU - Hofer, M. AU - Keintzel, J. AU - Kersevan, R. AU - Mertens, V. AU - Mether, L. AU - Molson, J. AU - Muttoni, Y. AU - Nosochkov, Y.M. AU - Ohmi, K. AU - Oide, K. AU - Osborne, J.A. AU - Parma, V. AU - Pieloni, T. AU - Pikhartova, H. AU - Raginel, V. AU - Redaelli, S. AU - Risselada, T. AU - Rivkin, L. AU - Ruehl, I. AU - Salvant, B. AU - Schoerling, D. AU - Seryi, A. AU - Shaposhnikova, E.N. AU - Tambasco, C. AU - Tavian, L.J. AU - Todesco, E. AU - Tommasini, D. AU - Tomás, R. AU - Valchkova-Georgieva, F. AU - Venturi, V. AU - Wollmann, D. AU - Zhou, D. AU - van Riesen-Haupt, L. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Updated High-Energy LHC Design J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - We present updated design parameters for a future High-Energy LHC. A more realistic turnaround time has led to a revision of the target peak luminosity, as well as a choice of a larger IP beta function, and longer physics fills. Pushed parameters of the Nb₃Sn superconducting cable together with a modified layout of the 16 T dipole magnets resulted in revised field errors, updated dynamic-aperture simulations, and an associated re-evaluation of injector options. Collimators in the dispersion suppressors help achieve satisfactory cleaning performance. Longitudinal beam parameters ensure beam stability throughout the cycle. Intrabeam scattering rates and Touschek lifetime appear benign. PB - JACoW Publishing CP - Geneva, Switzerland SP - 524 EP - 527 KW - injection KW - emittance KW - proton KW - impedance KW - damping DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPMP037 UR - http://jacow.org/ipac2019/papers/mopmp037.pdf ER - TY - CONF AU - Charles, T.K. AU - Aumon, S. AU - Holzer, B.J. AU - Oide, K. AU - Zimmermann, F. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Low Emittance Tuning of FCC-ee J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The FCC-ee project studies the design of a future 100 km e⁺/e⁻ circular collider for precision studies and rare decay observations in the range of 90 to 350 GeV center of mass energy with luminosities in the order of 10³⁶ cm⁻²s⁻¹. In order to reach these luminosity requirements, extreme focusing is needed in the interaction regions. For the Z energy (45.6 GeV) lattice, the maximum beta value is 8322 m, and the vertical beta function is 0.8 mm at the IP. These aspects of the FCC-ee lattice make it particularly susceptible to misalignments and field errors, and therefore present an appreciable challenge for emittance tuning. A challenging correction scheme is proposed to reduce the coupling and the vertical emittance. We describe a comprehensive correction strategy used for the low emittance tuning. The strategy includes special programs, that had been developed to optimise the lattice based on Dispersion Free Steering, linear coupling compensation based on Resonant Driving Terms and beta beat correction utilising response matrices. Thousands of misalignment and field error random seeds were introduced in MADX simulations and the final corrected lattices are presented. PB - JACoW Publishing CP - Geneva, Switzerland SP - 574 EP - 577 KW - emittance KW - coupling KW - lattice KW - quadrupole KW - sextupole DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPRB001 UR - http://jacow.org/ipac2019/papers/moprb001.pdf ER - TY - CONF AU - Nakazawa, Y. AU - Hasegawa, K. AU - Hayashizaki, N. AU - Iinuma, H. AU - Iwashita, Y. AU - Iwata, Y. AU - Kawamura, N. AU - Kitamura, R. AU - Kondo, Y. AU - Mibe, T. AU - Morishita, T. AU - Otani, M. AU - Saito, N. AU - Sue, Y. AU - Yamazaki, T. AU - Yasuda, H.Y. AU - Yoshida, M. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Development of Inter-Digital H-Mode Drift-Tube Linac Prototype with Alternative Phase Focusing for a Muon Linac in the J-PARC Muon G-2/EDM Experiment J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - An inter-digital H-mode drift-tube linac (IH-DTL) is developed in a muon linac at the J-PARC E34 experiment. IH-DTL will accelerate muons from 0.34 MeV to 4.5 MeV at a drive frequency of 324 MHz. Since IH-DTL adopts an APF method, with which the beam is focused in the transverse direction using the RF field only, the proper beam matching of the phase-space distribution is required before the injection into the IH-DTL. Thus, an IH-DTL prototype was fabricated to evaluate the performance of the cavity and beam transmission. As a preparation of the high-power test, a test coupler is designed and fabricated. In this paper, the development of the coupler and the result of the low-power measurement will be presented. PB - JACoW Publishing CP - Geneva, Switzerland SP - 606 EP - 609 KW - cavity KW - linac KW - DTL KW - coupling KW - experiment DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPRB017 UR - http://jacow.org/ipac2019/papers/moprb017.pdf ER - TY - CONF AU - Ohmori, C. AU - Otani, M. AU - Shimomura, K. AU - Takayanagi, T. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Conceptual Design of Negative-Muon Decelerator for Material Science J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - In 2018, a Negative-Muon Spin Rotation and Relaxation technique was developed in J-PARC Material and Life Science Facility. It is a novel scheme to investigate the motion of hydrogens in the chemicals and materials. To study small samples, the surface of materials and thin foils, a low energy negative muon beam is required. To decelerate intense 300-keV muons to 15-keV, we propose a system which consists of pulse generators and multi-gap induction decelerators. In this design, an inductive adder scheme is considered to use for the high voltage pulse source. High impedance magnetic alloy ring cores will be loaded in the decelerator cells. The high impedance cores which have much larger size than those for public use were developed for J-PARC RF systems and used for many applications including CERN booster RF, anti-proton deceleration and medical accelerator. In this paper, we present a conceptual design of muon deceleration system. PB - JACoW Publishing CP - Geneva, Switzerland SP - 610 EP - 612 KW - cavity KW - induction KW - experiment KW - impedance KW - power-supply DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPRB018 UR - http://jacow.org/ipac2019/papers/moprb018.pdf ER - TY - CONF AU - Okita, H. AU - Ikeda, N. AU - Ishi, Y. AU - Kinsho, M. AU - Kuriyama, Y. AU - Miyake, Y. AU - Mori, Y. AU - Muto, M. AU - Okabe, K. AU - Ono, Y. AU - Sato, A. AU - Taniguchi, A. AU - Uesugi, T. AU - Yonemura, Y. AU - Yoshimoto, M. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Beam Optics Study on FFA-MERIT Ring J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - Intense negative muon source MERIT (Multiplex Energy Recovery Internal Target) for the nuclear transformation to mitigate the long lived fission products from nuclear plants has been proposed. For the purpose of proof-of-principle of MERIT scheme, FFA ring has been developed. The results of beam optics study for MERIT ring will be reported in this conference. PB - JACoW Publishing CP - Geneva, Switzerland SP - 613 EP - 615 KW - injection KW - target KW - proton KW - betatron KW - acceleration DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPRB019 UR - http://jacow.org/ipac2019/papers/moprb019.pdf ER - TY - CONF AU - Watanabe, K. AU - Marutsuka, K. AU - Yoshida, Ma. AU - Yoshimoto, S.I. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Current Status of the High-Power RF Systems During Phase2 Operation in SuperKEKB J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The SuperKEKB is an asymmetric-energy two-ring collider consisting of the high-energy ring (HER) for 7 GeV electrons and the low-energy ring (LER) for 4 GeV positrons at KEK. Both the electron and positron beams are injected from the Linac injector complex, which includes a newly constructed 1.1 GeV positron damping ring (DR) to supply a high-quality low emittance positron beam to the LER. The high power RF system has a role to drive the ARES cavities and the superconducting RF cavities for the SuperKEKB. The operating frequency of RF system is 508.9 MHz. The required RF power from the klystron at maximum storage beam current is ~850 kW (CW). The number of RF stations is total 31 for the main ring (MR) and DR. The status of each high power RF components, troubles of them and operation condition that occurred during phase 2 commissioning from Feb 2018 to July 2018 will be reported in this paper. PB - JACoW Publishing CP - Geneva, Switzerland SP - 619 EP - 621 KW - klystron KW - cavity KW - operation KW - GUI KW - status DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPRB022 UR - http://jacow.org/ipac2019/papers/moprb022.pdf ER - TY - CONF AU - Yasuda, H.Y. AU - Iinuma, H. AU - Kawamura, N. AU - Kondo, Y. AU - Mibe, T. AU - Nakazawa, Y. AU - Otani, M. AU - Saito, N. AU - Sue, Y. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Design of the Wien-Filter Type Spin Rotator for the Low-Emittance Muon Beam J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - Muon linac is developed for the muon g-2/EDM experiment at J-PARC. In this experiment, ultra slow muon is accelerated to a momentum of 300 MeV/c with the four linac structures. This scheme offers new opportunity for precise measurements; it enables us to reverse muon polarization at early stage of acceleration. The reversal of polarization is a common method of precision polarization measurements as it can be used to identify or reduce systematic uncertainties dependent on time. It is necessary to accelerate muons and flip its spin without substantial emittance growth for the experimental requirement. As one of the candidates for our spin rotator, we are developing the Wien-filter type. In this poster, the design of the Wien-filter type spin rotator for the low emittance muon beam will be presented. PB - JACoW Publishing CP - Geneva, Switzerland SP - 622 EP - 625 KW - emittance KW - rfq KW - experiment KW - polarization KW - acceleration DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPRB023 UR - http://jacow.org/ipac2019/papers/moprb023.pdf ER - TY - CONF AU - Plostinar, D.C. AU - Eshraqi, M. AU - Gålnander, B. AU - Lebedev, V.A. AU - Prior, C.R. AU - Sato, Y. AU - Tang, J.Y. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Future High Power Proton Drivers for Neutrino Beams J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - Over the last two decades, significant efforts were made through several international studies to identify and develop technical solutions for potential Neutrino Factories and Superbeam Facilities. With many questions now settled, as well as clearer R&D needs, various proposals are being made for future facilities in China, Europe, Japan and North America. These include both developing and adapting existing machines as well as green-field solutions. In this paper, we review all the major accelerator programmes aimed at delivering high-power proton beams for neutrino physics. PB - JACoW Publishing CP - Geneva, Switzerland SP - 662 EP - 665 KW - linac KW - proton KW - operation KW - neutron KW - factory DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPRB045 UR - http://jacow.org/ipac2019/papers/moprb045.pdf ER - TY - CONF AU - Luo, Y. AU - Bassi, G. AU - Blaskiewicz, M. AU - Fischer, W. AU - Hao, Y. AU - Montag, C. AU - Ohmi, K. AU - Ptitsyn, V. AU - Qiang, J. AU - Smaluk, V.V. AU - Willeke, F.J. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Combined Strong-Strong and Weak-Strong Beam-Beam Simulations for Crabbed Collision in eRHIC J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - In the eRHIC, to compensate the geometric luminosity loss, local crab cavities on both sides of the interaction points are to adopted. The previous strong-strong beam-beam simulations showed that the luminosity degradation depends on the crab cavity frequency, proton synchrotron tune, proton bunch length and so on. In this article, we apply a combined strong-strong and weak-strong beam-beam simulation to investigate the incoherent and coherent beam motions with crabbed collison, and to calculate more realistic beam emittance growth rates and luminosity degradation rate. PB - JACoW Publishing CP - Geneva, Switzerland SP - 788 EP - 790 KW - electron KW - proton KW - simulation KW - luminosity KW - cavity DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPRB091 UR - http://jacow.org/ipac2019/papers/moprb091.pdf ER - TY - CONF AU - Kondo, Y. AU - Fang, Z. AU - Fukui, Y. AU - Futatsukawa, K. AU - Hirano, K. AU - Hori, T. AU - Ikegami, K. AU - Ishiyama, T. AU - Ito, T. AU - Ito, Y. AU - Kato, Y. AU - Kikuzawa, N. AU - Kitamura, R. AU - Kobayashi, F. AU - Miyao, T. AU - Morishita, T. AU - Nanmo, K. AU - Nemoto, Y. AU - Oguri, H. AU - Ohkoshi, K. AU - Otani, M. AU - Sato, Y. AU - Sawabe, Y. AU - Shibata, T. AU - Shinozaki, S. AU - Shinto, K. AU - Takahashi, D. AU - Tasaki, R. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Upgrade of the 3-MeV LINAC for Testing of Accelerator Components at J-PARC J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - We are now upgrading a 3-MeV linac at J-PARC. The old 30-mA RFQ is replaced by a spare one of the J-PARC 50-mA RFQ. The ion source is same as the J-PARC linac’s, therefore, the peak beam current is upgraded from 30 mA to 50 mA. This 3-MeV linac will be used for development of various accelerator components, such as beam dyagnostics devices, laser charge exchange equipments, new MEBT buncher, and so on. In this paper, present status of this 3-MeV test linac is presented. PB - JACoW Publishing CP - Geneva, Switzerland SP - 960 EP - 963 KW - rfq KW - linac KW - operation KW - MMI KW - experiment DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPTS046 UR - http://jacow.org/ipac2019/papers/mopts046.pdf ER - TY - CONF AU - Otani, M. AU - Futatsukawa, K. AU - Hirano, K. AU - Kondo, Y. AU - Liu, Y. AU - Miura, A. AU - Miyao, T. AU - Oguri, H. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Longitudinal Measurements and Beam Tuning in the J-PARC Linac MEBT1 J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - J-PARC linac is operated with design peak current of 50 mA from October 2018. Recently we succeeded in establishing longitudinal measurement at MEBT1, with which the beam matching is being studied in MEBT1. In this poster, recent measurements and beam tuning results in MEBT1 will be presented. PB - JACoW Publishing CP - Geneva, Switzerland SP - 968 EP - 970 KW - MEBT KW - linac KW - DTL KW - simulation KW - rfq DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPTS048 UR - http://jacow.org/ipac2019/papers/mopts048.pdf ER - TY - CONF AU - Tamura, J. AU - Kondo, Y. AU - Morishita, T. AU - Naito, F. AU - Nemoto, Y. AU - Otani, M. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - The First Replacement of the RF Window of the ACS Cavity J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - In 2013, the Annular-ring Coupled Structure (ACS) cavities were installed to the Japan Proton Accelerator Research Complex (J-PARC) linac. Since then, the ACS cavities have been stably running. Although any serious problem induced by the ACS RF window has not yet observed, we decided to replace the RF window of one ACS cavity, which is the eighteenth accelerating cavity in the order of beam energy (ACS18), by the newly manufactured one. The major motivations of the replacement are to check the surface condition of the RF window which have been under operation for nearly five years and to confirm the availability of the newly manufactured RF window. By making use of the summer maintenance period of 2018, we carried out the replacement. This was the first experience for us to replace the RF window installed to the ACS cavity in the linac accelerator tunnel. As for the removed RF window, there was no any abnormal warning found with the visual examination. At the starting up of the cavity’s operation after the maintenance period, we investigated how much time would be required for an RF conditioning. It took around fifty hours so that the peak RF power including the beam loading is stably input to the cavity through the new RF window. The ACS cavity with the new RF window is now stably operating. PB - JACoW Publishing CP - Geneva, Switzerland SP - 971 EP - 973 KW - cavity KW - linac KW - vacuum KW - operation KW - proton DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPTS049 UR - http://jacow.org/ipac2019/papers/mopts049.pdf ER - TY - CONF AU - Tamura, J. AU - Kondo, Y. AU - Morishita, T. AU - Naito, F. AU - Nemoto, Y. AU - Otani, M. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - VSWR Adjustment for ACS Cavity in J-PARC LINAC J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - In the Japan Proton Accelerator Research Complex (J-PARC) linac, negative hydrogen beams are accelerated from 190 MeV to 400 MeV by twenty-one Annular-ring Coupled Structure (ACS) accelerating cavities. The input coupler of the ACS high-beta cavity, which is the 21st accelerating cavity (ACS21) in the order of beam acceleration, had a comparatively larger value of the Voltage Standing Wave Ratio (VSWR) than those of the other ACS cavities. To adjust the VSWR of the ACS21, we designed and fabricated a rectangular waveguide with a capacitive iris which conduces to a better matching between the cavity and the waveguide. In the 2018 summer maintenance period, we installed the newly fabricated waveguide to the ACS21 in the position between the input coupler and the RF window. Consequently, the VSWR of the ACS21 was successfully decreased to the target value which leads to the critical coupling under the nominal accelerating condition with 50-mA peak beam current. PB - JACoW Publishing CP - Geneva, Switzerland SP - 974 EP - 976 KW - cavity KW - coupling KW - GUI KW - simulation KW - linac DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPTS050 UR - http://jacow.org/ipac2019/papers/mopts050.pdf ER - TY - CONF AU - Shimosaki, Y. AU - Bellan, L. AU - Brañas Lasala, B. AU - Cara, P. AU - Chauvin, N. AU - Comunian, M. AU - Duglue, G. AU - Dzitko, H. AU - Fagotti, E. AU - Heidinger, R. AU - Kasugai, A. AU - Kobayashi, H. AU - Kondo, K. AU - Oliver, C. AU - Pisent, A. AU - Podadera, I. AU - Sakamoto, K. AU - Sugimoto, M. AU - Takayama, K. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Lattice Design for 5MeV-125mA CW RFQ Operation in the LIPAc J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The installation and commissioning of the LIPAc are ongoing under the Broader Approach agreement, which is the prototype accelerator of the IFMIF for proof of princi-ple and design. The deuteron beam will be accelerated by the RFQ linac from 100 keV to 5 MeV during the com-missioning phase-B and by the SRF linac up to 9 MeV during the phase-C. The commissioning phase-B+ will be implemented between phase-B and C to complete the engineering validation of the RFQ linac before installing the SRF linac. The lattice for the deuteron beam of 5 MeV and 125 mA at the commissioning phase-B+ was designed. PB - JACoW Publishing CP - Geneva, Switzerland SP - 977 EP - 979 KW - linac KW - SRF KW - rfq KW - MMI KW - MEBT DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPTS051 UR - http://jacow.org/ipac2019/papers/mopts051.pdf ER - TY - CONF AU - Otani, M. AU - Fukao, Y. AU - Futatsukawa, K. AU - Hasegawa, K. AU - Iijima, T. AU - Iinuma, H. AU - Inami, K. AU - Ishida, K. AU - Kawamura, N. AU - Kitamura, R. AU - Kondo, Y. AU - Mibe, T. AU - Miyake, Y. AU - Morishita, T. AU - Nakazawa, Y. AU - Saito, N. AU - Shimomura, K. AU - Sue, Y. AU - Yamazaki, T. AU - Yasuda, H.Y. AU - Yotsuzuka, M. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Negative Muonium Ion Production With a C12A7 Electride Film J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - Negative muonium ion production is one of methods to cool muons. Since its discovery in 1987 by interactions of muons with a metal foil, it has been discussed that the production efficiency would be improved using a low-work function material. C12A7 (12CaO·7AlO3) was a well-known insulator as a constituent of alumina cement, but was recently confirmed to exhibit electric conductivity by electron doping. The C12A7 electride has lower work function (2.9 eV) and it was reported that nearly the same negative current signal as that with a bi-alkali material coated metal were observed in H⁻ formation. In this poster, the negative muonium production measurement with a Al foil and C12A7 electride film will be presented. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1175 EP - 1178 KW - target KW - experiment KW - positron KW - acceleration KW - electron DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUXXPLS2 UR - http://jacow.org/ipac2019/papers/tuxxpls2.pdf ER - TY - CONF AU - Mori, S. AU - Sato, D. AU - Yoshida, M. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - The Design Optimization of the Dielectric Assist Accelerating Structure for Better Heat and Gas Transfer J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The dielectric-assist accelerating (DAA) structure is a dielectric-inserted normal-conducting cavity, which provides high Q value at room temperature. This accelerating structure is composed of dielectric disks and a dielectric cylindrical layer inserted in a copper cavity. For the realistic operation, the removal of heat from the dielectric cells and the vacuum evacuation of gas inside the cylindrical layers have not considered yet. In order to solve the problems, we propose the optimized design of the DAA structure, where the extended part of the dielectric disk is embedded in the copper cavity and the choke structure is applied. We show the result of the electromagnetic-field simulation of the extended DAA structure and the thermal simulation to clarify the relation between a duty factor and maximum temperature of the dielectric cells. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1179 EP - 1181 KW - cavity KW - vacuum KW - multipactoring KW - embedded KW - lattice DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUXXPLS3 UR - http://jacow.org/ipac2019/papers/tuxxpls3.pdf ER - TY - CONF AU - Sugimoto, H. AU - Koiso, H. AU - Mori, K. AU - Morita, A. AU - Ohnishi, Y. AU - Tejima, M. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Optics Measurements at SuperKEKB Using Beam Based Calibration for BPM and BBA J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The beam-based calibration(BBC) technique for Beam-Position-Monitor(BPM) is applied in order to establish reliable optics measurement. In the BBC, a response model between beam position, charge and output signals of the BPM electrodes are introduced to calibrate the relative gain of the BPM electrodes. The gains are adjusted by total squares fitting so that the model reproduces the measured BPM signals. The Beam-Based Alignment(BBA) is also performed to determine the magnetic center of a quadrupole. Using BBC and BBA, the performance of the BPM system and optics correction are successfully improved. This talk presents what we experienced during the beam commissioning focusing on beam optics measurement and some details on the beam-based calibration scheme for BPM system. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1198 EP - 1202 KW - quadrupole KW - optics KW - betatron KW - emittance KW - coupling DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUZPLM2 UR - http://jacow.org/ipac2019/papers/tuzplm2.pdf ER - TY - CONF AU - Miura, K. AU - Kuniyasu, Y. AU - Kurimoto, Y. AU - Morita, Y. AU - Naito, D. AU - Oogoe, T. AU - Ooya, K. AU - Sagawa, R. AU - Shimogawa, T. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Magnet Power Supply Calibration with a Portable Current Measuring Unit at the J-PARC Main Ring J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - In the J-PARC MR, 96 bending magnets (BMs) are used in total. They are divided into 6 groups of 16 BMs. The 16 BMs in each group are connected in series and driven by a single power supply. Since all 96 BMs are symmetrically located in the ring, the magnet currents regulated by the 6 power supplies need to be same. Each power supply performs output current feedback control using electronic circuits including analog amplifications and AD / DA conversions. Due to individual differences of the electronic circuits, output current is generally expected to be different for each power supply. Therefore, we developed a current measurement unit with the portable DCCT as an independent reference. Further, we measured the magnet currents regulated by the 6 BM power supplies using the unit. We report the details of the unit as well as the results of the current measurements. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1263 EP - 1265 KW - power-supply KW - feedback KW - operation KW - timing KW - controls DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPMP015 UR - http://jacow.org/ipac2019/papers/tupmp015.pdf ER - TY - CONF AU - Shimogawa, T. AU - Kurimoto, Y. AU - Miura, K. AU - Morita, Y. AU - Naito, D. AU - Sagawa, R. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - New Power Supply of Main Magnets for J-Parc Main Ring Upgrade J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - It is plans that the proton beam power provided to experimental facilities increase with shortening repetition period in J-PARC Main Ring (MR). As the shorten repetition period, the replacement of the power converters for main magnets in J-PARC MR is necessary to cope with issues such as power fluctuation of the main grid and increase of the output voltage. We have considered and developed the power converters with a 10 MW class which have the capacitor banks with the large capacitance. In the end of 2017, the first new power converter for a bending magnets family, which is the largest power converter in this upgrade plan, was installed in J-PARC site and the power test is ongoing using a dummy and a real load. In this report, the first new power converter for a bending magnets family in J-PARC MR is reported including the test results. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1266 EP - 1268 KW - controls KW - extraction KW - operation KW - quadrupole KW - proton DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPMP016 UR - http://jacow.org/ipac2019/papers/tupmp016.pdf ER - TY - CONF AU - Tanimoto, Y. AU - Honda, T. AU - Jin, X.J. AU - Nogami, T. AU - Takai, R. AU - Yamamoto, M. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Vacuum Performance of the NEG-coated Chamber for U#19 at PF-ring J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - At the Photon Factory storage ring (PF-ring) in KEK, a new APPLE-II type elliptically polarizing undulator (U#19) was installed in October 2018. The U#19 vacuum chamber is 4.1 meters in length, and the beam channel with a 15x90 elliptical profile and two cooling-water channels alongside were formed by extrusion of A6060-T6 aluminum alloy. The inner surface of the beam channel is coated with a Ti-Zr-V Non-Evaporable Getter (NEG) thin film, as it has a high effective pumping speed and a low Photon Stimulated Desorption (PSD) yield. After the installation of the U#19, the neighboring uncoated chambers and vacuum components were baked out at 200 °C for 44 hours, and then the NEG coating was activated at 160 °C for 48 hours. As a result, the pressures in the neighboring chambers reached as low as 10⁻⁸ Pa. The conditioning of the vacuum chambers with irradiation of Synchrotron radiation evolved favorably as had been expected by a combined simulation of Synrad and Molflow, leading to a satisfactory recovery of the beam lifetime. Vacuum performance of the NEG-coated chamber was assessed especially by means of a residual gas analysis, and the properties of the NEG film were characterized by surface analyses including SEM, EDX, and XRD. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1276 EP - 1279 KW - vacuum KW - photon KW - simulation KW - MMI KW - undulator DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPMP019 UR - http://jacow.org/ipac2019/papers/tupmp019.pdf ER - TY - CONF AU - Hosaka, Y. AU - Honda, Y. AU - Kosuge, A. AU - Omori, T. AU - Sakaue, K. AU - Takahashi, T. AU - Uesugi, Y. AU - Urakawa, J. AU - Washio, M. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Mode-Locked Pulse Oscillation of a Self-Resonating Enhancement Optical Cavity J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - A power enhancement optical cavity is a compelling means of realizing a pulsed laser with a high peak power and high repetition frequency, which is not feasible using a simple amplifier scheme. However, a precise feedback system is necessary for maintaining the narrow resonance condition of the optical cavity; this has become a major technical issue in developing such cavities. We have developed a new approach that does not require any active feedback system, by placing the cavity in the outer loop of a laser amplifier. We report on the first demonstra-tion of a mode-locked pulse oscillation using the new system. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1471 EP - 1474 KW - cavity KW - laser KW - resonance KW - controls KW - feedback DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPGW032 UR - http://jacow.org/ipac2019/papers/tupgw032.pdf ER - TY - CONF AU - Obina, T. AU - Arakawa, D.A. AU - Egi, M. AU - Furuya, T. AU - Haga, K. AU - Hajima, R. AU - Harada, K. AU - Honda, T. AU - Honda, Y. AU - Honma, T. AU - Kako, E. AU - Kato, R. AU - Kawata, H. AU - Kobayashi, Y. AU - Kojima, Y. AU - Konomi, T. AU - Matsumura, H. AU - Miura, T. AU - Miyajima, T. AU - Nagahashi, S. AU - Nagai, R. AU - Nakai, H. AU - Nakamura, N. AU - Nakanishi, K. AU - Nigorikawa, K.N. AU - Nishimori, N. AU - Nogami, T. AU - Qiu, F. AU - Sagehashi, H. AU - Sakai, H. AU - Sakanaka, S. AU - Sawamura, M. AU - Shimada, M. AU - Tadano, M. AU - Takahashi, T. AU - Takai, R. AU - Tanaka, O.A. AU - Tanimoto, Y. AU - Uchiyama, T. AU - Umemori, K. AU - Yamamoto, M. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - 1 mA Stable Energy Recovery Beam Operation with Small Beam Emittance J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - A compact energy-recovery linac (cERL) have been operating since 2013 at KEK to develop critical components for ERL facility. Details of design, construction and the result of initial commissioning are already reported*. This paper will describe the details of further improvements and researches to achieve higher averaged beam current of 1 mA with continuous-wave (CW) beam pattern. At first, to keep the small beam emittance produced by 500 kV DC-photocathode gun, tuning of low-energy beam transport is essential. Also, we found some components degrades the beam quality, i.e., a non-metallic mirror which disturbed the beam orbit. Other important aspects are the measurement and mitigation of the beam losses. Combination of beam collimator and tuning of the beam optics can improve the beam halo enough to operate with 1 mA stably. The cERL has been operated with beam energy at 20 MeV or 17.5 MeV and with beam rep-rate of 1300 MHz or 162.5 MHz depending on the purpose of experiments. In each operation, the efficiency of the energy recovery was confirmed to be better than 99.9 %. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1482 EP - 1485 KW - operation KW - emittance KW - cavity KW - linac KW - gun DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPGW036 UR - http://jacow.org/ipac2019/papers/tupgw036.pdf ER - TY - CONF AU - Shimada, M. AU - Honda, Y. AU - Hotei, T. AU - Kato, R. AU - Miyajima, T. AU - Nakamura, N. AU - Obina, T. AU - Uchiyama, T. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Systematic Measurements of the Coherent THz Spectra by Magnetic Bunch Compression at the Compact ERL J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - Short electron bunch beam is one of the key elements of a Free Electron Laser (FEL) or intense THz coherent light source. The Energy Recovery Linac (ERL) has the strong advantage of operation of such an electron bunch at high repetition rate and is expected to increase the photon flux. At the Compact ERL in KEK site, we have demonstrated the magnetic bunch compression at the 180-degree return arc and measured the THz spectra of the Coherent Transition Radiation (CTR). This paper reports the revamped THz beamline and the improvement of the beam tuning as well as the systematic measurements of the THz spectra by magnetic bunch compression. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1486 EP - 1488 KW - optics KW - electron KW - radiation KW - sextupole KW - linac DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPGW037 UR - http://jacow.org/ipac2019/papers/tupgw037.pdf ER - TY - CONF AU - Takai, R. AU - Honda, T. AU - Kobayashi, Y. AU - Nagahashi, S. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Present Status of the PF-ring and PF-AR Operations J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The Photon Factory at KEK has been managing two synchrotron radiation sources, the PF-ring and PF-AR, for over 30 years. Although their operation time has been decreasing in recent years for budget reasons, continuous efforts to improve their performance have been made. In this paper, the operational status of these light sources for FY2018 is described. At the PF-ring, a first-generation undulator was renewed with the beamline components. A vacuum chamber for the new undulator was applied the NEG coating on the inner surface. This is the first attempt in Japanese light sources that the NEG-coated chamber is used for undulators. At the PF-AR, the top-up injection using the direct beam transport line was introduced to the user operation for the first time. Since modification of the beam injector LINAC for enabling simultaneous injection to the four different rings (the PF-ring, PF-AR, SuperKEKB HER and LER) was completed, this top-up operation no longer disturbs the operation of the other three rings. A low-energy operation of the PF-AR was also tested to secure more operation time within the limited budget. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1654 EP - 1657 KW - operation KW - injection KW - photon KW - undulator KW - ECR DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPGW106 UR - http://jacow.org/ipac2019/papers/tupgw106.pdf ER - TY - CONF AU - Honda, Y. AU - Aryshev, A. AU - Kato, R. AU - Miyajima, T. AU - Obina, T. AU - Shimada, M. AU - Takai, R. AU - Uchiyama, T. AU - Yamamoto, N. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Stimulated Emission of THz Coherent Diffraction Radiation in an Optical Cavity by a Multibunch Electron Beam J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - Accelerator-based terahertz (THz) radiation has been expected to realize a high-power broad-band source. Employing a low-emittance and short-bunch electron beam at a high repetition rate, a scheme to resonantly excite optical cavity modes of THz spectrum range via coherent diffraction radiation has been proposed. The confocal cavity design is the special case that resonance conditions of all the eigen modes coincide, resulting in realizing broad-band excitation. But in general cases of non-confocal cavities, the resonance condition depends on the mode, and the resonance peak becomes wide and weak. We performed an experiment with a non-confocal cavity as a follow-up experiment of that we have done with a confocal cavity. The result confirmed that the confocal design is the key for a broad-band source. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1763 EP - 1765 KW - cavity KW - experiment KW - radiation KW - resonance KW - electron DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPRB035 UR - http://jacow.org/ipac2019/papers/tuprb035.pdf ER - TY - CONF AU - Matsuba, S. AU - Fujimoto, M. AU - Hosaka, M. AU - Katoh, M. AU - Kawase, K. AU - Konomi, T. AU - Miyamoto, A. AU - Sasaki, S. AU - Yamamoto, N. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Experimental Demonstration of Vector Beam Generation With Tandem Helical Undulators J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - Vector beam is a light beam with spatially modulated polarization state across the beam. Particular examples of vector beam are radial and azimuthal polarization which have donut-shaped intensity and radially and azimuthally oriented linear polarization state. Vector beam has long been interest in the laser community and it is well known that vector beam can be created by superposing two optical vortex beams which have spiral wave fronts. It has been demonstrated that optical vortex beam can be generated from a helical undulator as harmonics. Therefore, we propose a scheme to generate vector beam by superposing two optical vortex beams from two helical undulators in tandem, based on the principle of the ’crossed undulator’. The experiment was carried out at UVSOR BL1U. In this paper, we describe the principle and the experimental details. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1766 EP - 1768 KW - polarization KW - undulator KW - experiment KW - radiation KW - simulation DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPRB037 UR - http://jacow.org/ipac2019/papers/tuprb037.pdf ER - TY - CONF AU - Otani, M. AU - Futatsukawa, K. AU - Hasegawa, K. AU - Iinuma, H. AU - Ito, T. AU - Iwashita, Y. AU - Kitamura, R. AU - Kondo, Y. AU - Mibe, T. AU - Morishita, T. AU - Naito, F. AU - Nakazawa, Y. AU - Saito, N. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Disk and Washer Coupled Cavity Linac Design and Cold-Model for Muon Linac J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - A disk and washer (DAW) coupled cavity linac (CCL) has been developed for a middle velocity part in a muon linac at the J-PARC E34 experiment. It will accelerate muons from v/c = 0.3 to 0.7 at an operational frequency of 1296 MHz. In this poster, the cavity designs, beam dynamics designs, and the cold-model measurements will be presented. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1924 EP - 1927 KW - cavity KW - linac KW - acceleration KW - emittance KW - operation DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPRB117 UR - http://jacow.org/ipac2019/papers/tuprb117.pdf ER - TY - CONF AU - Kuriki, M. AU - Masaki, K. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Negative Electron Affinity GaAs Cathode Activation With CsKTe Thin Film J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - Negative Electron Affinity (NEA) GaAs cathode is an unique device which can generate a highly polarized electron beam with circularly polarized light. The NEA surface is conventionally made by Cs and \rm O/NF₃ adsorption on the cleaned p-doped GaAs crystal, but the robustness of the cathode is very limited, so that the electron emission is easily lost by residual gas adsorption, ion back-bombardment, etc. To improve the cathode robustness, NEA activation with a stable thin-film on GaAs surface according to Hetero junction hypothesis has been proposed by the author. An experiment of the NEA activation with CsKTe thin film was carried out at Hiroshima University and a significant electron emission with 1.43 eV photon was observed which strongly suggested NEA activation. The cathode showed 16 to 20 times improvement of lifetime comparing to GaAs activated with Cs and O. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1986 EP - 1989 KW - cathode KW - electron KW - photon KW - vacuum KW - gun DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPTS026 UR - http://jacow.org/ipac2019/papers/tupts026.pdf ER - TY - CONF AU - Liu, Y. AU - Fang, Z. AU - Futatsukawa, K. AU - Ito, T. AU - Miura, A. AU - Miyao, T. AU - Morishita, T. AU - Moriya, K. AU - Okabe, K. AU - Otani, M. AU - Shibata, T. AU - Tamura, J. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Progress of J-PARC LINAC Commissioning J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - After energy and intensity upgrade to 400MeV and 50mA respectively, J-PARC linac were ready for 1 MW beam power from RCS. J-PARC is now successfully operated at 50mA/400MeV for 500kW at neutron target, and on the way to 1MW. The next milestones 1.2 and 1.5MW from RCS are relying on feasibility and property of increase of peak current to 60 mA and the pulse width to 600us in linac. Beam studies were carried out at linac to study the initial beam parameters from ion source/RFQ, to find the optimized lattice and matching, to clarify beam loss source and to mitigate the loss/residue dose for the power upgrade. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1990 EP - 1992 KW - linac KW - lattice KW - rfq KW - operation KW - DTL DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPTS027 UR - http://jacow.org/ipac2019/papers/tupts027.pdf ER - TY - CONF AU - Shibata, T. AU - Fan, K. AU - Hamano, K. AU - Ishii, K. AU - Matsumoto, H. AU - Sugimoto, T. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - The New Eddy Current type Septum Magnets for Upgrading of Fast Extraction in Main Ring of J-PARC J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The J-PARC Main Ring (MR) is working on imporved beam to 750 kW by shorting the repetition period from 2.48 s to 1.3 s which we call 1Hz operation. The septum magnets for fast extraction in MR will be improved to the new septum magnets which can operate 1Hz. The new magnets will be installed to MR in 2021. In this poster we will report about the new low field septum magnet for the fast extraction. The present septum magnets are conventional type. Therefore, we have problem in durability of thin septum coil by its magnetic vibration, and large leakage field at the exit of the circulating beam duct. The new septum magnets are eddy current type. The eddy current type does not have septum coil, but has a thin septum plate. We can expect that there is no problem in durability of septum coil, and leakage field can be reduced. The output of the present power supply are pattern current which of flat top is 10 ms width, the new one is short pulse which of one is 10 us. The short pulse consists of fundamental and 3rd harmonic sin-wave pulse. We can expect that the flatness and reproducibility of flat top current can be improved. We confirmed that 1Hz operation and high accuracy of its output current and magnetic field with the new septum magnet system. We had some problem in unexpected instability of output current. In this report we also summarize the measure against the instabillity. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1997 EP - 2000 KW - operation KW - septum KW - extraction KW - experiment KW - feedback DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPTS029 UR - http://jacow.org/ipac2019/papers/tupts029.pdf ER - TY - CONF AU - Shibata, T. AU - Fan, K. AU - Ishii, K. AU - Matsumoto, H. AU - Sugimoto, T. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - The New High Field Septum Magnets for Upgrading of Fast Extraction in Main Ring of J-PARC J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The J-PARC Main Ring (MR) is working on imporved beam to 750 kW by shorting the repetition period from 2.48 s to 1.3 s which we call 1Hz operation. There are fout high field septum magnet along the fast extraction line in the MR, and these will be improved to the new magnets which can operate 1Hz frequency. The new high field septa will be installed in 2021. In this poster we will report about the performance of these new septum magnets. These high field septum magnets are called Septum 30(SM30), 31(SM31), 32(SM32), 33(SM33). We will replace SM30, SM31, and SM32. One reasons of cethe replacement is installation of a large-size quadrupole magnet to upsteam postion of the septa. We need to change the longitudinal length of the septa. Second is large aperture of the beam duct for reduction of beam loss by the collision of the halo of the proton beam to the duct. The new high field SM30, SM31 and SM32 have large aperture. and the material of the beam ducts for extraction line are ceramics for reduction of amount of heat generation by eddy current on the surface of the duct. The maetial of the circulating duct are titanium for reduction of radioactivation. On the other hand, the power supply will not be replaced, then the current power supplies will be used for these new septa. The new SM30, SM31, and SM32 were produced in 2015. The first test operation of SM31 were conduced with 2.48 s repein 2015, and we have meaured the magnetic field without problem. In 2018, we conduced the first 1Hz operation with SM30. The minimum repetition period of the operation was 1.16 s without any problem. We measuered magnetic fields in the gap of the pole and in the circulating beam duct. In this report we will report the detail of the results of the operation and field measurement. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2001 EP - 2004 KW - operation KW - extraction KW - septum KW - flattop KW - power-supply DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPTS030 UR - http://jacow.org/ipac2019/papers/tupts030.pdf ER - TY - CONF AU - Shirakata, M.J. AU - Kuboki, H. AU - Takano, J. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Radiation Design of New 30 kW Beam Dump of J-PARC Main Ring J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The J-PARC Main Ring (MR) has a beam dump for the beam study and beam abort. Its present capacity is 7.5 kW in one hour average which is limited by radiation condition for the environments. The number of protons in one MR cycle is 2.6·10⁺¹⁴ in recent days, which corresponds to the beam power of 500 kW. As the top energy of J-PARC MR is 30 GeV, the number of available beam shots is restricted to less than twenty in one hour with such an intense beam. It imposes a big limitation on high power beam tuning and study. The number of protons is expected to become 3.3·10⁺¹⁴ for MW operation. Hence, an upgrade of the beam dump from 7.5 kW to 30 kW is planned. The radiation dose rate should be less than 0.25μSv/h on the ground. The backscattered neutron flux should be examined in the accelerator tunnel. The new dump design on radiation matters is described in this paper. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2005 EP - 2008 KW - neutron KW - vacuum KW - proton KW - radiation KW - site DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPTS032 UR - http://jacow.org/ipac2019/papers/tupts032.pdf ER - TY - CONF AU - Yamamoto, M. AU - Furusawa, M. AU - Hara, K. AU - Hasegawa, K. AU - Nomura, M. AU - Ohmori, C. AU - Shimada, T. AU - Sugiyama, Y. AU - Tamura, F. AU - Yoshii, M. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Vacuum Tube Operation Analysis for 1.2 MW Beam Acceleration in J-PARC RCS J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The J-PARC RCS has successfully accelerated 1 MW proton beam, matching the designed beam power. Therefore, we have considered acceleration beyond the designed beam power, with the next target being 1.2 MW. An issue for 1.2 MW beam acceleration is the rf system. The present anode power supply is limited by its output current, and the vacuum tube amplifier suffers from an unbalance of the anode voltage swing, arising from the combination of multi-harmonic rf driving and push-pull operation. We have investigated the mitigation of the maximum anode currents and unbalanced tubes by choosing appropriate circuit parameters of the rf cavity with the tube amplifier. We describe the analysis results of the vacuum tube operation for 1.2 MW beam acceleration in the RCS. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2017 EP - 2019 KW - acceleration KW - cavity KW - vacuum KW - operation KW - power-supply DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPTS035 UR - http://jacow.org/ipac2019/papers/tupts035.pdf ER - TY - CONF AU - Morita, A. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Status of Early SuperKEKB Phase-3 Commissioning J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - SuperKEKB is an asymmetric energy electron-positron collider for B-meson physics experiment. The beam collision with 3mm vertical beta function at the interaction point is confirmed during prior beam commissioning until July 2018. The next beam commissioning with the inner silicon vertex detectors so called "phase-3 commissioning" will start in March 2019. In the early part of next phase-3 commissioning, we plan to try the collision operation with over 1A stored beam current in order to exceed 1 x 10³⁴ cm⁻² s⁻¹ luminosity. We will report the preliminary results of the early stage of the SuperKEKB phase-3 commissioning. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2255 EP - 2257 KW - MMI KW - optics KW - detector KW - operation KW - luminosity DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEYYPLM1 UR - http://jacow.org/ipac2019/papers/weyyplm1.pdf ER - TY - CONF AU - Muto, R. AU - Arakaki, Y. AU - Kimura, T. AU - Matsumura, A. AU - Murasugi, S. AU - Okada, M. AU - Okamura, K. AU - Shimogawa, T. AU - Shirakabe, Y. AU - Tomizawa, M. AU - Toyama, T. AU - Yanaoka, E. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Current Status of Slow Extraction from J-PARC Main Ring J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - A 30 GeV proton beam accelerated in the J-PARC Main Ring (MR) is slowly extracted by the third integer resonant extraction and delivered to the hadron experimental hall. The slow extraction (SX) from the MR has unique characteristics that can be used to obtain a low beam loss rate. A dynamic bump scheme under achromatic condition drastically reduces beam hit rate on the septa devices. We have attained 50 kW SX operation at 5.2s cycle in current physics run. Slow extraction efficiency has been achieved to be very high, 99.5%. A beam instability during debunching with beam loss can be suppressed by a unique RF phase offset technique at MR injection. A spill duty factor indicating a uniformity for time structure of the extracted beam is typically 50%, which can be obtained by a feedback system using fast response quadrupoles, applying transverse RF field and so on. Future plans to improve present SX performances will be introduced. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2311 EP - 2314 KW - extraction KW - operation KW - proton KW - experiment KW - radiation DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPMP007 UR - http://jacow.org/ipac2019/papers/wepmp007.pdf ER - TY - CONF AU - Okamura, K. AU - Arakaki, Y. AU - Kimura, T. AU - Murasugi, S. AU - Muto, R. AU - Shirakabe, Y. AU - Tomizawa, M. AU - Yanaoka, E. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - A Consideration on the Transfer Function Between RQ Field and Slow Extraction Spill in the Main Ring of J-Parc J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - A 30 GeV proton beam accelerated in the J-PARC Main Ring (MR) is slowly extracted by the third integer reso-nant extraction and delivered to the hadron experimental facility. Increasing the duty of beam spill is one of the important issues in the slow extraction system. In the MR, the spill feedback system utilizing a digital signal processor (DSP) combined with EQ and RQ magnet is used to smooth the spill, where EQ defines a rough out-line of the slow extraction shape and RQ is used for the ripple cancelling. In this study, frequency domain charac-teristics between the current of RQ magnet and the beam spill was investigated by driving the RQ magnet with sinusoidal current, so that the transfer function from the current of RQ magnet to the spill signal is delivered. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2315 EP - 2317 KW - extraction KW - feedback KW - experiment KW - operation KW - controls DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPMP008 UR - http://jacow.org/ipac2019/papers/wepmp008.pdf ER - TY - CONF AU - Tomizawa, M. AU - Arakaki, Y. AU - Fujii, Y. AU - Fukao, Y. AU - Hashimoto, Y. AU - Igarashi, Y. AU - Kimura, T. AU - Mihara, S. AU - Moritsu, M. AU - Murasugi, S. AU - Muto, R. AU - Nishiguchi, H. AU - Okamura, K. AU - Shirakabe, Y. AU - Tamura, F. AU - Ueno, K. AU - Yanaoka, E. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - 8 Gev Slow Extraction Beam Test for Muon to Electron Conversion Search Experiment at J-PARC J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - A muon to electron conversion search experiment (COMET) planned at J-PARC needs 8 GeV bunched proton beams with a continuous 1 MHz pulse structure. In this experiment, an intensity ratio of the residual to the main pulsed beam, which is expressed as extinction, should be less than the level of 10⁻¹⁰. In RUN78 (Jan. to Feb., 2018), we have succeeded in slow extraction of 8 GeV protons with 7.3×1012 ppp, satisfies the COMET phase-I requirement, and the extinction derived from a timing measurement of secondary particles from the target shows a promising result. A mechanism to explain the measured extinction will be also described in this paper. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2322 EP - 2325 KW - kicker KW - extraction KW - timing KW - injection KW - electron DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPMP010 UR - http://jacow.org/ipac2019/papers/wepmp010.pdf ER - TY - CONF AU - Zimmermann, F. AU - Etisken, O. AU - Mounet, N. AU - Oeftiger, A. AU - Ogur, S. AU - Oide, K. AU - Papaphilippou, Y. AU - Salvant, B. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Damping Bunch Oscillations Due to Off-Axis Injection J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - In the FCC-ee pre-injector complex, a slightly modified SPS can serve as pre-booster. The baseline design foresees injecting the low-emittance electron and positron bunches off-axis into the SPS, and deploying strong wigglers to greatly enhance the radiation damping at the injection energy. We here compare the damping of large injection oscillations by means of radiation damping with the effect of other possible damping mechanisms such as a fast bunch-by-bunch feedback system and/or head-tail damping via nonzero chromaticity. As a by-product, we investigate the transverse beam stability. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2422 EP - 2425 KW - optics KW - injection KW - wiggler KW - damping KW - radiation DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPMP041 UR - http://jacow.org/ipac2019/papers/wepmp041.pdf ER - TY - CONF AU - Nagaslaev, V.P. AU - Brown, K.A. AU - Tomizawa, M. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Higher Multipoles in 3rd Integer Resonance Extraction J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The efficiency of slow extraction is becoming a limiting factor, as the demand for delivered beam power is constantly growing. New methods for improving extraction efficiency include folding the extraction separatrix using the higher multipoles. In this report we discuss a simple and effective approach to determine an optimal placement of those multipoles in the storage ring. This allows reduction of the beam losses and therefore, the level of prompt and residual radioactivity in the accelerator components and surrounding buildings by as much as 40% or more. We also explore here manipulating the higher order effects produced in the pure sextupole configurations for the same purpose and demonstrate that similar results can be achieved by only rearranging the sextupole magnets in the lattice. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2437 EP - 2439 KW - extraction KW - octupole KW - sextupole KW - multipole KW - simulation DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPMP045 UR - http://jacow.org/ipac2019/papers/wepmp045.pdf ER - TY - CONF AU - Hashimoto, Y. AU - Endo, M. AU - Hori, Y. AU - Murakami, M. AU - Murashima, K. AU - Muto, R. AU - Sakai, H. AU - Tachibana, M. AU - Tatami, A. AU - Tomizawa, M. AU - Toyama, T. AU - Uota, M. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Beam Profile Monitor for Slow Extracted Beam Using Multi-Layered Graphene at J-PARC J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - Extracted-beam profiles in slow extraction at J-PARC has been measured by using secondary electrons emitted from a target array made by multi-layered graphen, in real time during spill time of around 2 seconds. The target array consists of 20 ribbons with width of 1 mm, pitch of 2 mm, and thickness of 1.1 micron. Secondary-electron current at each channel is measured by a current amplifier having sensitivity more than 1 pA. These configuration produces useful information for beam dynamics in slow extraction. We have set this monitor at the entrance of a septum magnet, then we can also measure the last few-turns beam with the extracted beam simultaneously. We will discuss about features of this instrument and recent beam study with 51 kW extracted-beams. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2532 EP - 2535 KW - target KW - electron KW - extraction KW - proton KW - real-time DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPGW030 UR - http://jacow.org/ipac2019/papers/wepgw030.pdf ER - TY - CONF AU - Kitamura, R. AU - Futatsukawa, K. AU - Hayashi, N. AU - Hirano, K. AU - Kondo, Y. AU - Kosaka, S. AU - Miyao, T. AU - Moriya, K. AU - Nemoto, Y. AU - Oguri, H. AU - Otani, M. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Development of the Bunch Shape Monitor Using the Carbon-Nano Tube Wire J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - A bunch shape monitor (BSM) is one of the important instruments to measure the longitudinal phase space distribution. The information of the bunch length measured by the BSM is useful to tune phases of the accelerating cavities in the linear accelerator. For example, in the J-PARC linac, three BSM’s using the tungsten wire are installed and tested at the ACS section to measure the bunch shapes between the accelerating cavities. However, this conventional BSM is hard to measure the bunch shape of H⁻ beam with 3 MeV at the beam transport between the RFQ and DTL sections, because the wire is broken around the center region of the beam. The new BSM using the carbon-nano-tube (CNT) wire is being developed to be able to measure the bunch shape of the H⁻ beam with 3 MeV. One challenge to introduce the CNT wire for the BSM is the measure to the discharge. The careful attention should be paid to apply the high voltage of 10 kV to the CNT wire. The several measures are taken to suppress the discharge from the wire and operate the CNT-BSM. This presentation reports the current status of the development and future prospective for the CNT-BSM. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2543 EP - 2546 KW - electron KW - high-voltage KW - vacuum KW - operation KW - DTL DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPGW033 UR - http://jacow.org/ipac2019/papers/wepgw033.pdf ER - TY - CONF AU - Jang, S.W. AU - Hayano, H. AU - Kim, E.-S. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Development of L-band Cavity BPM for STF J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - We developed a L-band beam position monitor with position resolution of few hundred nano meter for Superconducting Test Faciliy(STF) in KEK. The L-band BPM was developed to install inside the superconducting cryomodule of STF in KEK and it’s test was performed at Accelerator Test Facility in KEK. The three L-band BPM are fabricated and installed at the end of Linac of ATF. The position resolution measurement was performed with new L-band BPM electronics. In this talk, we will describe about the development of L-band BPM and its beam test results of nano meter level beam position resolution with new electronics system. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2547 EP - 2549 KW - cavity KW - electron KW - electronics KW - linac KW - simulation DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPGW034 UR - http://jacow.org/ipac2019/papers/wepgw034.pdf ER - TY - CONF AU - Kaji, H. AU - Hirose, M. AU - Iitsuka, Y. AU - Obina, T. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Archive System of Beam Injection Information at SuperKEKB J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The archive system is one of the most important tools for the modern accelerators. It records the machine parameters during the operation so that we can retrieve and review the status of machine anytime later. SuperKEKB develops the injection archiver system. This system records the injection related parameters, pulse-by-pulse*. The information related with beam injections is fully recorded and it can be utilize to understand the condition of injection operation. Besides, the recorded data can be utilized also for the understanding of beam background related with injections. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2550 EP - 2553 KW - injection KW - background KW - operation KW - kicker KW - linac DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPGW036 UR - http://jacow.org/ipac2019/papers/wepgw036.pdf ER - TY - CONF AU - Rehman, M.A. AU - Furukawa, K. AU - Hisamatsu, H. AU - Iinuma, H. AU - Mibe, T. AU - Nakayama, H. AU - Ohsawa, S. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Beam Control and Monitors for the Spiral Injection Test Experiment J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - A new experiment at J-PARC (E34) is under construction in order to measure the muon’s g-2 to unprecedented precision of 0.1 ppm and electric dipole moment up to the sensitivity of 10-21 e.cm in order to explore new physics beyond the standard model. A novel three-dimensional spiral injection scheme has been devised to inject and store the beam into a small diameter MRI-type storage magnet for E34. The new injection scheme features smooth injection with high storage efficiency for the compact storage magnet. However, spiral injection scheme is an unproven idea, therefore, a Spiral Injection Test Experiment (SITE) is underway to establish this injection scheme. The SITE is consist of 80 keV thermionic electron gun, two-meter-long beamline, and a solenoidal storage magnet. In order to match the beam with the solenoidal field, several optical elements have been placed on the beamline to control the beam phase space. The DC electron beam spiral track has been confirmed by the de-excitation of the nitrogen gas in the vacuum chamber of the storage magnet. A current monitor system has been developed in order to extract the beam current and geometrical information of three-dimensional trajectory. An electric chopper system to produce the pulsed beam and beam monitors to detect the pulsed beam will also be discussed in this paper. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2557 EP - 2560 KW - injection KW - experiment KW - electron KW - solenoid KW - site DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPGW038 UR - http://jacow.org/ipac2019/papers/wepgw038.pdf ER - TY - CONF AU - Sato, K. AU - Hamada, E. AU - Hashimoto, Y. AU - Igarashi, S. AU - Koseki, T. AU - Sato, Y. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Multi-Ribbon Profile Monitor for High Power Proton Beam at J-PARC MR Abort Line J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - Japan Proton Accelerator Research Complex (J-PARC) Main Ring (MR), the world-class high intensity proton synchrotron, provides proton beam to two experimental facilities with two extraction modes: Fast extraction (FX) and Slow extraction (SX). The number of protons per pulse (ppp) in MR recorded the world highest value of 2.6×10¹⁴ in the FX mode. Now we are planning to increase the ppp further up to 3.3×10¹⁴ in near future. The beam profile is one of the most important parameters to discuss the high intensity beam dynamics in MR. Monitors using multi-wires / ribbons are effective to measure the beam profile with good accuracy and wide dynamic range. However, they cause significant beam losses by interactions with high-intensity circulating beam in synchrotrons. Recently, we installed new multi-ribbon profile monitor (MRPM) in an abort line in MR. The abort line is one of the extracted beam lines of the FX system. It has a quadrupole doublet which is called Abort Q and transports extracted beam to a beam dump. The FX system can extract the circulating beam in MR with an arbitrary energy. Performing the single-pass measurement with MRPM and changing the transfer matrix by sweeping field strength of Abort Q, the emittance of the extracted beam can be measured. In this paper, we present the design, manufacturing, and results of the first beam test of newly installed MRPM system. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2561 EP - 2563 KW - target KW - proton KW - extraction KW - emittance KW - electron DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPGW039 UR - http://jacow.org/ipac2019/papers/wepgw039.pdf ER - TY - CONF AU - Yotsuzuka, M. AU - Futatsukawa, K. AU - Hasegawa, K. AU - Iijima, T. AU - Iinuma, H. AU - Inami, K. AU - Kawamura, N. AU - Kitamura, R. AU - Kondo, Y. AU - Mibe, T. AU - Miyake, Y. AU - Morishita, T. AU - Nakazawa, Y. AU - Otani, M. AU - Saito, N. AU - Shimomura, K. AU - Sue, Y. AU - Yamazaki, T. AU - Yasuda, H.Y. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Development of the Longitudinal Beam Monitor with High Time Resolution for a Muon LINAC in the J-PARC E34 Experiment J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The J-PARC E34 experiment aims to measure the muon anomalous magnetic moment and the electric dipole moment with a high precision. In this experiment, ultra-slow muons generated from thermal muonium production and laser resonance ionization are accelerated in a multistage muon linac. In order to satisfy the experimental requirements, a suppression of the emittance growth between different accelerating cavities is necessary, and the transverse and longitudinal beam matching is important. Longitudinal beam monitor has to measure the bunch width with a precision of 1% corresponding to several tens of picoseconds. In addition, the beam monitor should be sensitive to a single muon, because the beam intensity during the commissioning is lower than the designed intensity. Therefore, we are developing a longitudinal beam monitor using a microchannel plate (MCP), and a measurement system using photoelectrons to estimate the performance of the beam monitor. On November 2018, the beam monitor has been successfully used in the muon RF acceleration test at the J-PARC. In this presentation, the results of the performance evaluation for this beam monitor are reported. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2571 EP - 2574 KW - laser KW - experiment KW - linac KW - acceleration KW - DTL DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPGW042 UR - http://jacow.org/ipac2019/papers/wepgw042.pdf ER - TY - CONF AU - Bergamaschi, M. AU - Aryshev, A. AU - Karataev, P. AU - Kieffer, R. AU - Lefèvre, T. AU - Lekomtsev, K. AU - Mazzoni, S. AU - Potylitsyn, A. AU - Schloegelhofer, A. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Recent Results using Incoherent Cherenkov Diffraction Radiation for Non-Invasive Beam Diagnostics J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - When a relativistic charged particle travels at a short distance from the surface of dielectric material Cherenkov Diffraction Radiation (ChDR) is produced inside the dielectric. Recent observation of incoherent ChDR in the visible spectrum has opened the possibility of using this radiation for non-invasive beam size and position measurements. An experimental test to study this technique for highly directional beam position measurement has been initiated on the CLEAR facility at CERN, whilst another experimental investigation is underway at the Accelerator Test Facility 2 (ATF2) at KEK, Japan, to measure the resolution limit of ChDR for beam imaging diagnostics. This contribution presents the latest experimental results from both of these test facilities. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2654 EP - 2657 KW - radiation KW - experiment KW - photon KW - diagnostics KW - beam-diagnostic DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPGW077 UR - http://jacow.org/ipac2019/papers/wepgw077.pdf ER - TY - CONF AU - Iwashita, Y. AU - Fuwa, Y. AU - Geng, R.L. AU - Hayano, H. AU - Tongu, H. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - High Density Mapping for Superconducting Cavities J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - High density mapping system for superconducting cavities are under development. Testing on the stiffener X-ray mapping system at JLAB showed consistent results in comparison with simultaneously taken GM tube or ion chamber output signals. The system provides better visi-bility as shown by data briefly reported here. In addition to the temperature and the X-ray mapping, a sensitive magnetic field mapping system with high spatial density is also under development. The magnetic field sensor is AF755B, whose operations at cryogenic temperatures are already reported by other group. Our development status using the magnetic field sensor will be reported. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2860 EP - 2862 KW - cavity KW - cryogenics KW - radiation KW - status KW - operation DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPRB025 UR - http://jacow.org/ipac2019/papers/weprb025.pdf ER - TY - CONF AU - Tamura, F. AU - Furusawa, M. AU - Hara, K. AU - Hasegawa, K. AU - Nomura, M. AU - Ohmori, C. AU - Shimada, T. AU - Sugiyama, Y. AU - Yamamoto, M. AU - Yoshii, M. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Simulations of Beam Loading Compensation in a Wideband Accelerating Cavity Using a Circuit Simulator Including a LLRF Feedback Control J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - Magnetic alloy cavities are employed in the J-PARC RCS to generate high accelerating voltages. The cavity, which is driven by a vacuum tube amplifier, has a wideband frequency response and the beam loading in the cavity is multiharmonic. Therefore, the tube must generate a multiharmonic output current. An LTspice circuit model is developed to analyze the vacuum tube operation and the compensation of the multiharmonic beam loading. The model includes the cavity, tube amplifier, beam current, and LLRF feedback control. The feedback control consists of the I/Q demodulator including low pass filters, PI control, and I/Q modulator. In this presentation, we present the implementation of the LLRF functions in the LTspice simulations. The preliminary simulation results are also presented. The simulations fairly agree with the beam test results. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2863 EP - 2866 KW - controls KW - cavity KW - feedback KW - simulation KW - vacuum DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPRB026 UR - http://jacow.org/ipac2019/papers/weprb026.pdf ER - TY - CONF AU - Yasui, T.Y. AU - Igarashi, S. AU - Koseki, T. AU - Ohmi, K. AU - Sato, Y. AU - Satou, K. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Tune Shifts and Optics Modulations in the High Intensity Operation at J-PARC MR J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - J-PARC Main Ring (MR) is the intensity-frontier proton accelerator. The beam intensity of 2.6×10¹⁴ protons per pulse has been achieved for the current user operation. In this high-intensity operation, the tune spread caused by the space-charge is one of the main reasons for beam loss. The modulation of the betatron function and the tune shift were simulated with a PIC algorithm calculation code*. The simulation results showed that the space-charge effects were dominant in small particle action, and the sextupole fields effects were dominant in large particle action. Because sextupole strength is large in MR, sextupole fields induce substantial tune shifts. At the benchmark of the space-charge simulation, the simulation results matched the analytical space-charge calculations performed without sextupoles. It was found that the betatron function was modulated at most 6% by the space-charge effects and at most 8% by the effects of sextupoles in J-PARC MR. These effects to the injection beam optics matching and to the beam aperture will be investigated. PB - JACoW Publishing CP - Geneva, Switzerland SP - 3148 EP - 3151 KW - space-charge KW - simulation KW - betatron KW - sextupole KW - quadrupole DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPTS024 UR - http://jacow.org/ipac2019/papers/wepts024.pdf ER - TY - CONF AU - Lyapin, A. AU - Aryshev, A. AU - Boogert, S.T. AU - Gibson, S.M. AU - Lekomtsev, K. AU - Terunuma, N. AU - Tishchenko, A.A. AU - Urakawa, J. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Energy Modulation of Electron Beam in Corrugated Dielectric Waveguide J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - Energy modulated electron beams have a wide range of applications in accelerator physics, for example they can serve as drivers in resonant wakefield acceleration schemes. A strong wakefield induced energy modulation can be produced using a dielectric lined waveguide, the resultant micro-bunched beam is capable of producing coherent terahertz radiation *. We report on observation of energy modulation due to self-wakefields in a few picosecond duration and ~1 nC charge electron bunches of LUCX facility at KEK. To produce the modulation, we used a corrugated dielectric waveguide with an inner radius of 2 mm and a period of corrugation of 10 mm. In this case, the period of corrugation is longer than the wavelength of the main accelerating mode. We show electromagnetic simulations of on-axis electric fields leading to an optimisation of the corrugation period allowing to enhance the accelerating/decelerating fields compared to dielectric lined waveguides with a constant inner radius. PB - JACoW Publishing CP - Geneva, Switzerland SP - 3248 EP - 3250 KW - experiment KW - simulation KW - wakefield KW - acceleration KW - electron DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPTS055 UR - http://jacow.org/ipac2019/papers/wepts055.pdf ER - TY - CONF AU - Morikawa, Y. AU - Haga, K. AU - Hagiwara, M. AU - Harada, K. AU - Higashi, N. AU - Honda, T. AU - Honda, Y. AU - Hosumi, M. AU - Kamiya, Y. AU - Kato, R. AU - Kawata, H. AU - Kobayashi, Y. AU - Matsumura, H. AU - Mitsuda, C. AU - Miura, T. AU - Miyajima, T. AU - Nagahashi, S. AU - Nakamura, N. AU - Nigorikawa, K.N. AU - Nogami, T. AU - Obina, T. AU - Sagehashi, H. AU - Sakai, H. AU - Shimada, M. AU - Tadano, M. AU - Takai, R. AU - Takaki, H. AU - Tanaka, O.A. AU - Tanimoto, Y. AU - Toyoda, A. AU - Uchiyama, T. AU - Ueda, A. AU - Umemori, K. AU - Yamamoto, M. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - New Industrial Application Beamline for the cERL in KEK J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The new beam line for the industrial applications is constructed at the cERL (compact Energy Recovery LINAC) in KEK. In these applications, only north straight sections of cERL consisting of injector and main LINAC will be used. The test for the radio isotope production and electron beam irradiation for the materials are firstly planned with very small beam current without energy recovery. PB - JACoW Publishing CP - Geneva, Switzerland SP - 3475 EP - 3477 KW - target KW - radiation KW - electron KW - linac KW - vacuum DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-THPMP012 UR - http://jacow.org/ipac2019/papers/thpmp012.pdf ER - TY - CONF AU - Nakamura, N. AU - Kako, E. AU - Kato, R. AU - Kawata, H. AU - Miyajima, T. AU - Sakai, H. AU - Umemori, K. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Challenges Towards Industrialization of the ERL-FEL Light Source for EUV Lithography J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - EUV Lithography is going to HVM (high volume manufacturing) stage with 250-W-class laser-produced plasma sources and it is important to develop a new-type EUV light source to meet future demand for higher power. Energy-recovery linac based free-electron lasers (ERL-FELs) are possible candidates of a high-power EUV light source that can distribute 1 kW power to multiple scanners simultaneously. In Japan, an ERL-FEL based EUV light source has been designed using available technologies without much development to demonstrate generation of EUV power more than 10 kW and the EUV-FEL Light Source Study Group for Industrialization has been established since 2015 to realize industrialization of the light source and the related items. For industrialization, high availability is essential as well as high power and reduction of the light source size is also required. In this paper, we will report an overview of the designed ERL-FEL light source for EUV lithography and some activities for the industrialization and describe considerations and developments for obtaining high availability and size reduction of the light source. PB - JACoW Publishing CP - Geneva, Switzerland SP - 3478 EP - 3481 KW - FEL KW - cavity KW - SRF KW - cathode KW - undulator DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-THPMP013 UR - http://jacow.org/ipac2019/papers/thpmp013.pdf ER - TY - CONF AU - Taufik, T. AU - Adachi, T. AU - Takayama, K. AU - Wake, M. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Crucial Transverse Beam Dynamics of the Racetrack-shape Fixed Field Induction Accelerator for Giant Cluster Ions J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - A racetrack-shape fixed field induction accelerator (RAFFIA) for high energy giant cluster ion acceleration was proposed in 2015*. The RAFFIA employs 4 bending magnets with gradient in the main pole face and reverse field strip at its front side which generate strong focusing in both planes. Beam dynamics properties of the RAFFIA of 140 MeV for C-60 have been evaluated by linear optics. The result has been confirmed with a help of 3D macro-particle computer simulation**. It is identified that the issue of COD generated from field non-uniformity associated with a finite size of the bending magnet is inherent. The programmed COD correction by steering magnets are discussed as well as the importance of uniformity in the magnet field profile. So far it has been unknown what beam current is acceptable in the RAFFIA. In order to estimate space-charge effects in the RAFFIA under design, the 2D core (σ) evolution equation has been derived from the envelope equation perturbed by space-charge fields. Resonant structures and chaotic motion in the phase space of (σ,σ’) have been clarified as a function of beam current. Those results were justified by macro-particle tracking based on a renormalized transfer matrix approach***. As a result, it turns out that the 8+ C-60 beam of 200 uA is acceptable. PB - JACoW Publishing CP - Geneva, Switzerland SP - 3643 EP - 3646 KW - acceleration KW - injection KW - induction KW - space-charge KW - optics DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-THPGW029 UR - http://jacow.org/ipac2019/papers/thpgw029.pdf ER - TY - CONF AU - Morita, R. AU - Higashiguchi, T. AU - Koshiba, Y. AU - Ota, S. AU - Sakaue, K. AU - Urakawa, J. AU - Washio, M. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Development of Yb-Based Laser System for Crab Crossing Laser-Compton Scattering J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - We are going to demonstrate the principle of crab crossing in laser-Compton scattering which creates head-on collision in a pseudo manner to enhance the intensity of laser-Compton X-ray. When the electron beam is tilted by half of the collision angle, the scat-tered X-rays becomes the largest. Calculation shows that more than threefold luminosity will be achieved in our system and could be larger luminosity depending on the beam parameters. The intensity of scattered light can be efficiently enhanced by using a collision laser with high intensity, high quality and ultrashort pulse duration. Thus, we have introduced a regenera-tive amplifier using ceramics thin-disk as a collision laser and developed a dedicated laser system. In this conference, we will report on our laser system and results of crab crossing laser-Compton scattering. PB - JACoW Publishing CP - Geneva, Switzerland SP - 3657 EP - 3659 KW - laser KW - electron KW - luminosity KW - experiment KW - scattering DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-THPGW035 UR - http://jacow.org/ipac2019/papers/thpgw035.pdf ER - TY - CONF AU - Zhang, R. AU - Honda, Y. AU - Kumano, H.K. AU - Toyotomi, N. AU - Yoshida, M. AU - Zhou, X. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Hybrid Yb/Nd Laser System for RF Gun in SuperKEKB Phase II and Phase III Commissioning J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - SuperEKKB phase II commissioning has been finished in the summer of 2018. By use of Ytterbium doped fiber and Nd:YAG hybrid laser system, 2.3 nC electron beam with low emittance has been achieved at the end of linac, which is generated by RF gun. The electron beam is injected and stored in High Energy Ring successfully. Basing on these operation experiences, the Nd:YAG laser system will be used for the early stages of SuperKEKB phase III commissioning. After the update of laser system during 2018 summer maintenance, about 5.3 nC electron charge is generated by RF gun. Beside this, the laser spatial and temporal reshaping experiment has been being done in order to realize the electron beam with low emittance and low energy spread. Meanwhile, a perspective towards the next step Yb:YAG laser system is also introduced in this paper. PB - JACoW Publishing CP - Geneva, Switzerland SP - 3663 EP - 3666 KW - laser KW - electron KW - gun KW - MMI KW - injection DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-THPGW037 UR - http://jacow.org/ipac2019/papers/thpgw037.pdf ER - TY - CONF AU - Liu, N. AU - Arakawa, D.A. AU - Du, B. AU - Katagiri, H. AU - Kobayashi, T. AU - Matsumoto, T. AU - Michizono, S. AU - Miura, T. AU - Qiu, F. AU - Yano, Y. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Development Status of RF Reference Phase Stabilization System for SuperKEKB Injector LINAC J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - SuperKEKB injector linear accelerator (LINAC) has 600 m beam lines which consist of 8 sectors. The 2856 MHz RF reference signals are distributed to each sector with long phase stabilized optical fiber (PSOF). The RF reference phase stability requirement is estimated to be 0.2°(RMS) corresponding to 200 fs. The prototype of RF reference phase stabilization system with single mode optical circulator was implemented and demonstrated in the laboratory. The returned phase drift is compensated by a piezo-driven fiber stretcher. The transmitted phase through 120 m PSOF is stabilized to 41 fs (pk-pk), which fulfilled the requirement. This paper introduces the RF reference phase stabilization system and reports the preliminary feedback result. PB - JACoW Publishing CP - Geneva, Switzerland SP - 3879 EP - 3881 KW - linac KW - controls KW - feedback KW - photon KW - distributed DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-THPRB033 UR - http://jacow.org/ipac2019/papers/thprb033.pdf ER - TY - CONF AU - Takahashi, H. AU - Hatakeyama, S. AU - Ishiyama, T. AU - Miyao, T. AU - Sawabe, Y. AU - Suzuki, T. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Development of Beam Window Protection System for J-PARC Linac J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - In J-PARC Linac, beam study (including beam conditioning) is mainly performed using beam dump. A beam window is installed in the beam line to each beam dump. It is considered that the parameters of acceptable beam　to able to be injected the beam window are the 50 mA current, the 100 micro-sec width and the 2.5 Hz repetition. On the other hand, at beam study of Linac, the beam with higher power than these parameters are not used. Therefore, the beam study was started and performed only after the operator checked that the beam parameters are within the acceptable values. However, at the beam study of 2018, a beam windows of 0-degree dump was cracked because the beam that exceeds acceptable parameters was injected due to human error. Then, beam study using 0-degree dump was impossible at all. And, in order not to cause such accident again, we began to develop the beam window protection system. Moreover, as soon as possible, implementation of the system was required. Therefore, we designed and developed this system by improving it based on the particle management system which can measure all 25 Hz beam. We have developed a beam window protection system that monitors the beam current for each shot and accumulated beam current for a prescribed time and inhibits the beam by MPS when either value exceeds the threshold. Moreover, we succeeded in developing and implementing this system in a short time. This paper is described about development and function test of beam window protection system. PB - JACoW Publishing CP - Geneva, Switzerland SP - 3886 EP - 3889 KW - linac KW - operation KW - PLC KW - vacuum KW - site DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-THPRB035 UR - http://jacow.org/ipac2019/papers/thprb035.pdf ER - TY - CONF AU - Tawada, M. AU - Kikuchi, M. AU - Sakamoto, Y. AU - Someya, H. AU - Tenjin, K. AU - Tokuchi, A. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Development of Injection and Extraction Kickers for SuperKEKB Damping Ring J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - SuperKEKB is a double ring asymmetric collider to study the B meson physics, which is an upgrade project of KEKB. The 7 GeV electron (HER) and the 4 GeV positron ring (LER) collides at an interaction point. The positron beam produced by linac cannot meet the dynamic aperture restrictions of LER. Damping ring (DR) is required to reduce its injection emittance. Damping ring (DR) for SuperKEKB has two kicker magnets for the injection and the extraction, respectively. These kickers are required to meet the following specifications: (1) rise and fall time does not exceed 100 ns, (2) two bunches which are 96 ns apart must be kicked by single pulse, (3) the stability of peak current for the extraction kickers must be less than 0.1 %. Kicker magnets are designed as a conventional kicker with a ferrite core. The pulse shape is a double half sine for the two bunch injection. In order to achieve short rise time, a saturable inductance is used. The design and performance of kicker magnets and the power supplies are reported. PB - JACoW Publishing CP - Geneva, Switzerland SP - 3890 EP - 3892 KW - kicker KW - extraction KW - injection KW - power-supply KW - damping DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-THPRB036 UR - http://jacow.org/ipac2019/papers/thprb036.pdf ER - TY - CONF AU - Toyama, T. AU - Kobayashi, A. AU - Kuboki, H. AU - Okada, M. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Improved Frequency Characteristics Using Multiple Stripline Kickers J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - One of the important ingredient in the intra-bunch transverse feedback is a kicker. The frequency characteristics of the kicker suffers from the transit-time factor, sin(kl)/kl. We examine the frequency characteristics of multiple kickers system. Relation between the excitation patterns of the multiple kickers and the frequency characteristics are presented. PB - JACoW Publishing CP - Geneva, Switzerland SP - 3893 EP - 3895 KW - kicker KW - feedback KW - controls KW - pick-up KW - extraction DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-THPRB037 UR - http://jacow.org/ipac2019/papers/thprb037.pdf ER - TY - CONF AU - Li, S. AU - Fang, Z. AU - Fukui, Y. AU - Futatsukawa, K. AU - Qiu, F. AU - Sato, Y. AU - Shinozaki, S. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - The Realization of Iterative Learning Control for J-PARC LINAC LLRF Control System J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The beam current of j-parc linac was planned to increase to 60 mA. The stronger beam current will lead to higher beam loading effect. Due to the low Q factor of cavity in high β section of linac, the traditional PID feedback & feedforward control method may have to face huge challenges. In order to make the system run better at 60 mA, the iterative learning control (ILC) method was put forward to use in LLRF control system. All the ILC operations are done in EPICS-PC. By installing the PyEpics module, we can use python programs to realize the data interaction between EPICS system and PC and further realize the ILC algorithm. In this paper, the architecture of ILC methods will be introduced. The performance of ILC method will be reported. PB - JACoW Publishing CP - Geneva, Switzerland SP - 4155 EP - 4157 KW - controls KW - linac KW - experiment KW - LLRF KW - DTL DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-THPTS022 UR - http://jacow.org/ipac2019/papers/thpts022.pdf ER - TY - CONF AU - Mitsuda, C. AU - Honiden, T. AU - Kobayashi, Y. AU - Nagahashi, S. AU - Nakanishi, T. AU - Nogami, T. AU - Obina, T. AU - Sasagawa, A. AU - Takai, R. AU - Takaki, H. AU - Uchiyama, T. AU - Ueda, A. AU - Yokoyama, A. AU - Yokoyama, T. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Accelerator Implementing Development of Ceramics Chamber with Integrated Pulsed Magnet for Beam Test J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - We advance the development of Ceramics Chamber Integrated Pulsed Magnet (CCIPM) of air-core type as the application to low emittance ring with a narrow bore of light source accelerator in the future. The CCIPM is composed of ceramics cylinder of 60 mm diameter and four copper coils, which are implanted in the groove penetrated on the ceramic thickness along 30 cm length by silver brazing*. In addition to this structure, we succeeded in the implementations of cable connecting base that mechanically connect the coils and power supply with feeder lines and the pattern shape coating inside the ceramic cylinder. Improved brazing technique made it possible to braze the coil and the base on the coil at the same time that the coils are implanted in the ceramic thickness. Newly developed functional coating can reduce the eddy current caused by main magnetic field and pass the alternate component of beam wall current by capacitance structure. We report the details about the performance from the viewpoint of vacuum, magnetic field, insulation on the accelerator implementation with the approach to new technical development, and the preparation progress of beam test in beam-transport line. PB - JACoW Publishing CP - Geneva, Switzerland SP - 4164 EP - 4166 KW - kicker KW - vacuum KW - dipole KW - power-supply KW - injection DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-THPTS027 UR - http://jacow.org/ipac2019/papers/thpts027.pdf ER - TY - CONF AU - Sugimoto, T. AU - Ishii, K. AU - Matsumoto, H. AU - Shibata, T. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Recent Improvements and Future Upgrades of the J-PARC Main Ring Kicker Systems J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - J-PARC Main Ring provides 500kW proton beam to the long baseline neutrino oscillation experiment (T2K). In order to increase the beam intensity to improve the sensitivity of the CP violation study in neutrino sector, shorter repetition cycle and higher beam current are required. As part of the upgrade project, both injection and fast-extraction (Fx) kicker magnet systems have been improved. Air-cooled non-inductive ceramic resistors are used as the impedance-matching terminator for the injection kicker magnet. Power consumption and temperature rise of the termination resistor due to the beam induced current was simulated to optimize the number of parallel of the resistors. Efficiency of cooling fans was also simulated to improve the cooling ability. For the Fx kicker magnet, a fast charging power supply of the modulator was developed and deployed to shorten the charging period from 1.4 sec to 0.2 sec. This paper represents the simulation results, performance of the charging unit and future upgrade plans. PB - JACoW Publishing CP - Geneva, Switzerland SP - 4167 EP - 4170 KW - kicker KW - operation KW - power-supply KW - injection KW - extraction DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-THPTS028 UR - http://jacow.org/ipac2019/papers/thpts028.pdf ER - TY - CONF AU - Okamura, K. AU - Fukuda, K. AU - Kaito, T. AU - Kitai, H. AU - Kumamoto, D. AU - Lim, S. AU - Naito, F. AU - Sakamoto, K. AU - Takayama, K. AU - Tokuchi, A. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Development of a Pulsed Power Supply Utilizing 13 kV Class SiC-MOSFET J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - To resolve the drawback of conventional thyratron switches, development of a semiconductor high voltage switch utilizing a 13 kV class SiC-MOSFET developed by Tsukuba Power Electronics Constellations (TPEC) is proceeding. At first, the device evaluation test was carried out with a resistive load circuit. With the conditions of drain voltage of 10 kV and load resistance of 1 kΩ, turn on loss Eon, turn off loss Eoff, rise time Tr and fall time Tf were 1.7 mJ, 1.1 mJ, 64 ns, and 75 ns, respectively. As to gate charge characteristics, required electric charge to increase gate source voltage from 0 V to 20 V was about 80 nC. Thereafter, the 2s-12p switch array was designed and assembled, where 12 MOSFETs are equally aligned on a circle shaped circuit board and two circuit boards are stacked in series. A 14 kV-490 A-5 us pulse with a rise time of 430 ns in the long pulse mode and a 18 kV-318 A-1 us pulse with a rise time of 289 ns in the short pulse mode were successfully demonstrated. This switch will be installed as a turn-off switch for the injec-tion ES kicker in the KEK-DA. PB - JACoW Publishing CP - Geneva, Switzerland SP - 4364 EP - 4367 KW - pulsed-power KW - high-voltage KW - power-supply KW - electron KW - operation DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-FRXXPLM3 UR - http://jacow.org/ipac2019/papers/frxxplm3.pdf ER - TY - CONF AU - Nishiguchi, H. AU - Fujii, Y. AU - Fukao, Y. AU - Hashimoto, Y. AU - Igarashi, Y. AU - Mihara, S. AU - Moritsu, M. AU - Muto, R. AU - Sarin, P. AU - Tamura, F. AU - Tomizawa, M. AU - Ueno, K. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Extinction Measurement of J-PARC MR with 8 GeV Proton Beam for the New Muon-to-Electron Conversion Search Experiment - COMET J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - At J-PARC, extraction tests of a 8GeV pulsed proton beam from Main Ring (MR) have been successfully completed by a team drawn from the Accelerator Laboratory Group and the COherent Muon to Electron Transition (COMET) Experimental Group. The COMET Experiment aims to find new physics beyond the Standard Model by searching for the coherent neutrinoless conversion of a muon to an electron in muonic atoms, so-called mu-e conversion. This requires an extremely clean pulsed beam, and development of this beam plays a key role in the pursuit of the highest level of sensitivity. This successful extraction test is the clearing of a major milestone for the forthcoming experiment. The goal of the extraction tests was to confirm the beam quality under the customized MR operation mode. The J-PARC MR usually accelerates the proton beam (at one bunch per 600ns) up to 30GeV. But in the test, the MR instead accelerates the proton beam (at one bunch per 1.2us) up to 8GeV. The number of protons leaking between proton bunches, so-called EXTINCTION, must be less than one for every 10¹⁰ protons in the bunch. Extraction tests in the customized mode were conducted in January and February 2018 and resulted in many successes. In this test, leakage protons between bunches was successfully reduced below the objective of 10^{−10} of the number of protons in a bunch. This is a great success to guarantee the quality of proton beam required by COMET experiment. In addition, the time development of proton leakage was also precisely studied with several RF settings which enables us to further improve the extinction. In this paper, the result of extinction measurement and future prospect of beam extinction improvement is presented in addition to the detailed description of customized MR operation. PB - JACoW Publishing CP - Geneva, Switzerland SP - 4372 EP - 4375 KW - proton KW - experiment KW - extraction KW - timing KW - kicker DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-FRXXPLS2 UR - http://jacow.org/ipac2019/papers/frxxpls2.pdf ER -