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 - Shobuda, Y. AU - Kamiya, J. AU - Moriya, K. AU - Okabe, K. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Coupling Impedance of the Collimator Without RF-Shields at the RCS in 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 - All holes on the chamber walls of synchrotrons should be filled with the radiofrequency (RF)-shields to suppress coupling impedances that excite beam instabilities. In a synchrotron, titanium nitride (TiN)-coated RF-shields are installed with collimators. If the holes, through which the collimator jaw enters and exits the chamber, are filled with such RF-shields, the shields may break down as the dynamic coefficient of TiN increases in vacuum. At the Rapid Cycling Synchrotron (RCS), the RF-shields are eliminated from the collimator after demonstrating that the effect due to the RF-shields is negligible on the impedance at low frequencies. PB - JACoW Publishing CP - Geneva, Switzerland SP - 163 EP - 166 KW - impedance KW - simulation KW - synchrotron KW - collimation KW - proton DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPGW035 UR - http://jacow.org/ipac2019/papers/mopgw035.pdf ER - TY - CONF AU - Saha, P.K. AU - Harada, H. AU - Hotchi, H. AU - Shobuda, Y. AU - Takayanagi, T. AU - Tamura, F. AU - Watanabe, Y. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Dynamic Variation of Chromaticity for Beam Instability Mitigation in the 3-GeV RCS 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 - We have studied many other dynamic approaches from that reported in the IPAC 2018 for transverse beam instability mitigation in the presence of strong space charge in the 3-GeV RCS of J-PARC. One of such a method is the introduction of an excess of chromaticity from that of natural chromaticity by reversing the sextupole magnetic fields from the middle of the acceleration cycle. The benifits of this method are twofold. It allows to utilize sextupole for chromaticty correction at lower energy and also mitigate the beam instability at higher energy because of introducing higher chromaticity. We first carried out numerical simulations by using ORBIT code, experimentally verified and then applied for the machine operation. The detail of simulation and measurements results are presented in this paper. PB - JACoW Publishing CP - Geneva, Switzerland SP - 171 EP - 173 KW - simulation KW - emittance KW - extraction KW - injection KW - impedance DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPGW037 UR - http://jacow.org/ipac2019/papers/mopgw037.pdf ER - TY - CONF AU - Yee-Rendón, B. AU - Kondo, Y. AU - Maekawa, F.M. AU - Meigo, S.I. AU - Tamura, J. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Beam Optics Design of the Superconducting Region of the JAEA ADS J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The Japan Atomic Energy Agency (JAEA) is proposing an Accelerator Driven Subcritical System (ADS) for the transmutation of the nuclear waste. ADS will consist of a superconducting CW proton linear accelerator of 30MW and a subcritical nuclear reactor core. The main part of the acceleration will take part in the superconducting region using five types of radio frequency cavities. The ADS operation demands a high intensity and reliability of the beam. Therefore, the beam optics design plays a fundamental role to reduce the beam loss, control emittance growth and beam halo. PB - JACoW Publishing CP - Geneva, Switzerland SP - 181 EP - 183 KW - emittance KW - linac KW - cavity KW - controls KW - lattice DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-MOPGW040 UR - http://jacow.org/ipac2019/papers/mopgw040.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 - 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 - 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 - 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 - Kamiya, J. AU - Horino, K. AU - Kotoku, K. AU - Miki, N. AU - Shobuda, Y. AU - Takayanagi, T. AU - Yamamoto, K. AU - Yanagibashi, T. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - New Design of Vacuum Chambers for Radiation Shield Installation at Beam Injection Area of 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 - One of the issues in the J-PARC 3 GeV rapid cycling synchrotron is the high residual radiation dose around the beam injection point. A radiation shield is necessary to reduce radiation exposure of workers when maintenance is performed there. A space to install the radiation shield should be secured by newly designing a structure of the vacuum chamber at the injection point and the alumina ceramics beam pipes for the shift bump magnets. To make the space for the shield, the chamber is lengthened along the beam line and the cross-sectional shape is changed from circle to rectangle. The displacement and inner stress of the vacuum chamber due to atmospheric pressure was evaluated to be enough small by the calculation. For the ceramics beam pipe’s rf-shield, the damping resistor was effective to reduce the induced modulation voltages by the pulsed magnetic field. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1255 EP - 1258 KW - vacuum KW - injection KW - radiation KW - damping KW - flattop DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPMP013 UR - http://jacow.org/ipac2019/papers/tupmp013.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 - 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 - Hotchi, H. AU - Harada, H. AU - Takayanagi, T. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - J-PARC RCS: High-Order Field Components Inherent in the Injection Bump Magnets and Their Effects on the Circulating Beam During Multi-Turn Injection 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 utilizes four sets of pulsed dipole magnets for the formation of injection orbit bump. The injection bump magnets have a large aspect ratio (gap length/core length), so there are other high-order field components inherent in their magnetic fields in addition to the main dipole component. The high-order field components, which locally exist in the injection section not following the lattice super-periodicity, have a significant influence on the circulating beam during multi-turn injection via the excitation of high-order random betatron resonances. This paper discusses the detailed mechanism of emittance growth and beam loss caused by the high-order field components of the injection bump magnets including its correction scenario on the basis of numerical simulation and experimental results. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2009 EP - 2012 KW - injection KW - resonance KW - simulation KW - sextupole KW - operation DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPTS033 UR - http://jacow.org/ipac2019/papers/tupts033.pdf ER - TY - CONF AU - Takayanagi, T. AU - Horino, K. AU - Ueno, T. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Development of Low Inductance Circuit for Radially Symmetric Circuit J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - Radiation symmetric type circuits using semiconductors of SIC-MOSFETs, one of next generation semiconductors, are composed of circuits in which many semiconductor switches are multiplexed in series and in parallel. Since the lengths of all parallel circuits are equal, the output waveform will not be distorted due to timing jitter or level change. This circuit is useful for outputting the waveform of ultrafast short pulse. Therefore, we have developed a circuit that achieves further low inductance by making the power transmission circuit into a double circular ring structure equal to the coaxial shape. Compare the inductance value obtained from the structure and the output waveform. In addition, we compare the calculation and the actual measurement in the actual test and present the verification result of the developed circular ring structure. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2013 EP - 2016 KW - experiment KW - impedance KW - kicker KW - high-voltage KW - operation DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPTS034 UR - http://jacow.org/ipac2019/papers/tupts034.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 - Kamiya, J. AU - Yamamoto, K. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Operation Status of J-PARC Rapid Cycling Synchrotron J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The 3 GeV rapid cycling synchrotron (RCS) at the Japan Proton Accelerator Research Complex (J-PARC) provides more than 500 kW beams to the Material and Life Science Facility (MLF) and Main Ring (MR). In such a high-intensity hadron accelerator, even losing less than 0.1% of the beam can cause many problems. Such lost protons can cause serious radio-activation and accelerator component malfunctions. Therefore, we have conducted a beam study to achieve high-power operation. In addition, we have also maintained the accelerator components to enable stable operation. This paper reports the status of the J-PARC RCS over the last year. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2020 EP - 2023 KW - operation KW - proton KW - vacuum KW - status KW - synchrotron DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-TUPTS036 UR - http://jacow.org/ipac2019/papers/tupts036.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 - Kamiya, J. AU - Hikichi, Y. AU - Kinsho, M. AU - Moriya, K. AU - Ogiwara, N. AU - Okabe, K. AU - Wada, K. AU - Yamada, I. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Evaluation of 2-D Transverse Beam Profile Monitor Using Gas Sheet at 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 - A transverse beam profile monitor, which detects ions or luminescence generated by the interaction between the beam and the gas molecules distributed in a sheet shape, has been developed in the J-PARC LINAC. To know about the gas density distribution of the sheet-shaped gas, which affects the intensity distribution of the detected signal, the calculation by the Monte Carlo simulation code was performed. The calculation results showed that the gas with a narrow width along beam direction distributes enough uniformly within a realistic beam cross-sectional size. In addition, the unsaturated region against the MCP voltage and the injected gas pressure are evaluated based on the measurement with a beam. The results showed that the measurement in the low injected gas pressure with the appropriate applied voltage range is important to measure the beam profile in the unsaturated region. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2539 EP - 2542 KW - injection KW - linac KW - simulation KW - factory KW - experiment DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPGW032 UR - http://jacow.org/ipac2019/papers/wepgw032.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 - Ogiwara, N. AU - Hikichi, Y. AU - Hori, Y. AU - Kamiya, J. AU - Kinsho, M. AU - Yamada, I. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Development of a Dense Gas Sheet Target for a 2D Beam Profile Monitor J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - We have been developing a dense gas sheet target to realize a non-destructive and fast-response beam profile monitor for the accelerators in J-PARC. The beaming effect in vacuum science and technology has been employed for making a gas sheet. The gas sheet with a thickness of ~ 1 mm and the density of 2 x 10⁻⁴ Pa was successfully obtained. Then, we have successfully measured the profiles of the 400 MeV H⁻ ion beam in J-PARC linac by detecting the ions generated through the collision of this gas sheet to the H⁻ beam. This time, we have developed the gas sheet with the density of more than 10-3 Pa using a circular slit. The details of the new gas sheet generator will be shown. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2554 EP - 2556 KW - electron KW - experiment KW - simulation KW - vacuum KW - target DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPGW037 UR - http://jacow.org/ipac2019/papers/wepgw037.pdf ER - TY - CONF AU - Yamada, I. AU - Hikichi, Y. AU - Kamiya, J. AU - Kinsho, M. AU - Ogiwara, N. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Development of a Gas Distribution Measuring System for Gas Sheet Beam Profile Monitor 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 profile monitor is needed for measuring one of the beam parameters of high intensity accelerator to avoid radioactivating the systems. A monitor with sheet-shaped gas that can measure the beam profile nondestructively in two dimensions is developing. One of issues to introduce the monitor in accelerator is that the gas distribution is not uniform. Obtaining correct beam profile data needs to measure the gas distribution data because signal from the monitor is in proportion to beam intensity and gas distribution. A system analyzing distribution of ions produced from the gas using electron beam to measuring gas distribution in three dimensions is developing. An electron gun that produces ideal narrow beam, electrodes that forms parallel electric field toward micro-channel plate(MCP), and phosphor constitute the system. The electron beam that ionizes the gas which needs to be measured, produced ions are induced to MCP, and image on phosphor gives gas distribution data. In preliminary experiment for inspecting the measuring principle, experimental results agreed with simulation. The details of this system and the results of gas measuring experiment are reported. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2567 EP - 2570 KW - electron KW - injection KW - experiment KW - detector KW - simulation DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPGW041 UR - http://jacow.org/ipac2019/papers/wepgw041.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 - 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 - Montoya Soto, G.R. AU - Duarte Galván, C. AU - Valerio, C.A. AU - Yee-Rendón, B. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Electromagnetic Design and Characterization of an S-band 3-Cell RF Accelerating Cavity J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - An S-Band (2998 MHz) RF cavity to accelerate electrons was developed taking into account the beam space charge, the relativistic change in velocity of the low energy beam particle distribution through the cavity and the emittance growth. The electromagnetic design and geometry optimization were done using the codes Poisson Superfish and CST Studio. In addition, beam dynamics simulations were done using the program Travel to optimize the emittance and take into account the space charge effect. The machining was done in a CNC machining center. Measurements of the cavity resonance frequencies were carried out and compared with the obtained by the simulations with good agreement between them. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2867 EP - 2869 KW - cavity KW - emittance KW - simulation KW - electron KW - acceleration DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPRB027 UR - http://jacow.org/ipac2019/papers/weprb027.pdf ER - TY - CONF AU - Yee-Rendón, B. AU - Kondo, Y. AU - Maekawa, F.M. AU - Meigo, S.I. AU - Tamura, J. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Electromagnetic Design of the Low Beta Cavities for the JAEA ADS J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The Japan Atomic Energy Agency (JAEA) is designing a superconducting CW proton linear accelerator for the ADS project. The superconducting region will use five types of radio frequency cavities. In the region from 2 to 180 MeV the acceleration will be done using Half Wave Resonator (HWR) and Single Spokes (SS) cavities. HWR cavities will accelerate the beam from 2 to 10 MeV with a geometrical beta of 0.08 and the SS ones will do from 10 to 180 MeV using two cavity families with geometrical betas of 0.16 and 0.43. The results of electromagnetic model design are presented and the comparison with similar cavities from other projects are included. PB - JACoW Publishing CP - Geneva, Switzerland SP - 2870 EP - 2872 KW - cavity KW - SRF KW - linac KW - proton KW - superconductivity DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPRB028 UR - http://jacow.org/ipac2019/papers/weprb028.pdf ER - TY - CONF AU - Yee-Rendón, B. AU - Kondo, Y. AU - Maekawa, F.M. AU - Meigo, S.I. AU - Tamura, J. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Design of the Elliptical Superconducting Cavities for the JAEA ADS J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - The superconducting CW proton linear accelerator for an Accelerator Driven Subcritical System (ADS) proposed by Japan Atomic Energy Agency (JAEA) employs elliptical cavities for the final acceleration of 180 MeV to 1.5 GeV. Since this energy region implies a change of beta from 0.55 to 1, two cavity models were developed using the geometrical betas of 0.68 and 0.89 to improve the acceleration efficiency. The study of the electromagnetic design was simulated using SUPERFISH (SF) code and python program to do variable scan, the results were benchmarked with CST Microwave Studio program (CST). PB - JACoW Publishing CP - Geneva, Switzerland SP - 2873 EP - 2876 KW - cavity KW - superconducting-cavity KW - SRF KW - simulation KW - acceleration DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-WEPRB029 UR - http://jacow.org/ipac2019/papers/weprb029.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 - 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 - Kinsho, M. AU - Abe, K. AU - Kamiya, J. AU - Nakamura, T. ED - Boland, Mark ED - Tanaka, Hitoshi ED - Button, David ED - Dowd, Rohan ED - Schaa, Volker RW ED - Tan, Eugene TI - Effect of Nitric Hydrofluoric Acid Treatment on Brazing of Alumina Ceramics and Pure Titanium J2 - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019 CY - Melbourne, Australia T2 - International Particle Accelerator Conference T3 - 10 LA - english AB - Alumina ceramics vacuum chamber which is used for the 3GeV rapid-cycling synchrotron (RCS) in J-PARC is composed of alumina duct, titanium (Ti) flanges and Ti sleeves. Before brazing the alumina duct and the Ti sleeves, the Ti sleeves were treated with nitric hydrofluoric acid. The purpose of this study is to clear the effect of this treatment for titanium material. It was cleared by SEM observation that the roughness of the titanium material after the nitric hydrofluoric acid treatment becomes big. It was also measured that the thickness of oxide film on surface of the titanium material was 12.7 nm before treatment and 6.0 nm after treatment. As a result of measuring the wettability of the brazing material which was silver brazing filler metal (Ag: 72%, Cu: 28%) on the Ti surface and the diffusion of the Ti material into the brazing material, it became clear that both the clearing of oxide layer on the alumina ceramics and the vacuum condition of the vacuum heating furnace were important for brazing between alumina ceramics and pure titanium. PB - JACoW Publishing CP - Geneva, Switzerland SP - 4161 EP - 4163 KW - vacuum KW - electron KW - controls KW - experiment KW - gun DA - 2019/06 PY - 2019 SN - 978-3-95450-208-0 DO - DOI: 10.18429/JACoW-IPAC2019-THPTS026 UR - http://jacow.org/ipac2019/papers/thpts026.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 -