TY  - CONF
AU  - Dhital, B.
AU  - Delayen, J.R.
AU  - Derbenev, Y.S.
AU  - Douglas, D.
AU  - Krafft, G.A.
AU  - Lin, F.
AU  - Morozov, V.S.
AU  - Zhang, Y.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - Equilibria and Synchrotron Stability in Two Energy Storage Rings
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - In a dual energy storage ring, the electron beam passes through two loops at markedly different energies E_{L}, and E_{H}, i.e., energies for low energy loop and high energy loop respectively. These loops use a common beamline where a superconducting linac at first accelerates the beam from EL to EH and then decelerates the beam from EH to EL in the next pass. There are two basic solutions to the equilibrium problems possible, i.e., ’Storage Ring’ (SR) equilibrium and ’Energy Recovery Linac’ (ERL) equilibrium. SR equilibrium mode more resembles the usual single loop storage ring with strong synchrotron motion and ERL equilibrium mode is the case where RF in two beam passes nearly cancels. Calculations based on linear transfer matrix formalism show that longitudinal stability exists for both SR mode and ERL mode in two energy storage rings.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 364
EP  - 366
KW  - electron
KW  - storage-ring
KW  - damping
KW  - simulation
KW  - focusing
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-MOPGW104
UR  - http://jacow.org/ipac2019/papers/mopgw104.pdf
ER  - 

TY  - CONF
AU  - Guo, J.
AU  - Fox, J.D.
AU  - Mastoridis, T.
AU  - Rimmer, R.A.
AU  - Wang, H.
AU  - Wang, S.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - Transient Beam Loading and Mitigation in JLEIC Collider Rings
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - The Jefferson Lab Electron-Ion Collider (JLEIC) is an asymmetric high luminosity ring-ring collider proposed as the next major R&D facility for the nuclear physics community. Both of JLEIC’s electron and ion collider rings have high beam current with gaps serving the pur-poses of beam abort, ion clearing, etc. Such a time-varying beam loading in the RF cavities would generate modulation in cavity RF phase/voltage, causing cyclic shift of collision point and potential luminosity loss. We studied a few approaches to mitigate the RF phase modu-lation and IP shift, such as correcting the RF phase/voltage modulation with traditional LLRF feed-back, one-turn feedback (OTFB), or RF feedforward (FF); optimizing the bunch fill pattern to limit the RF phase/voltage modulation to a small fraction of the bunch trains in the collider ring; or matching the RF phase modulation in the two rings. The preliminary re-sults are discussed in this paper.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 758
EP  - 761
KW  - electron
KW  - cavity
KW  - klystron
KW  - luminosity
KW  - beam-loading
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-MOPRB080
UR  - http://jacow.org/ipac2019/papers/moprb080.pdf
ER  - 

TY  - CONF
AU  - Luo, Y.
AU  - Hao, Y.
AU  - Qiang, J.
AU  - Roblin, Y.
AU  - Willeke, F.J.
AU  - Zhang, H.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - Simulation Challenges for eRHIC Beam-Beam Study
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - The 2015 Nuclear Science Advisory Committee Long Rang Plan identified the need for an electron-ion collider (EIC) facility as a gluon microscope with capabilities beyond those of any existing accelerator complex. To reach the required high energy, high luminosity, and high polarization, the eRHIC design, based on the existing heavy ion and polarized proton collider RHIC, adopts a very small \beta-function at the interaction points, a high collision repetition rate, and a novel hadron cooling scheme. A full crossing angle of 22 mrad and crab cavities for both electron and proton rings are required. In this article, we will present the high priority R\&D items related to the beam-beam interaction studies for the current eRHIC design, the simulation challenges, and our plans and methods to address them. Recent progresses on this project are reported too.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 785
EP  - 787
KW  - electron
KW  - proton
KW  - simulation
KW  - damping
KW  - emittance
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-MOPRB090
UR  - http://jacow.org/ipac2019/papers/moprb090.pdf
ER  - 

TY  - CONF
AU  - Nissen, E.A.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - An Increased Extraction Energy Booster Complex for the Jefferson Lab Electron Ion Collider
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - The proposed Jefferson Lab Electron Ion Collider (JLE-IC) envisions an ion complex composed of an ion linac, two booster synchrotrons and a collider ring. The evolving design of the JLEIC booster required an increase in the extraction energy of the booster from 8 to 12.1 GeV kinetic energy, necessitating two machines instead of one. The decision was also made to switch to warm magnets, thus increasing the total radius of the 8 GeV booster. The second booster is now the same size as the collider rings. In this work we present the new designs for JLEIC’s Low Energy Booster (LEB) and High Energy Booster (HEB).
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 797
EP  - 798
KW  - booster
KW  - collider
KW  - electron
KW  - extraction
KW  - proton
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-MOPRB098
UR  - http://jacow.org/ipac2019/papers/moprb098.pdf
ER  - 

TY  - CONF
AU  - Wijethunga, S.A.K.
AU  - Benesch, J.F.
AU  - Delayen, J.R.
AU  - Hannon, F.E.
AU  - Krafft, G.A.
AU  - Mamun, M.A.
AU  - Palacios Serrano, G.G.
AU  - Poelker, M.
AU  - Suleiman, R.
AU  - Zhang, S.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - Simulation Study of the Emittance Measurements in  Magnetized 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  - Electron cooling of the ion beam is key to obtaining the required high luminosity of proposed electron-ion colliders. For the Jefferson Lab Electron Ion Collider, the expected luminosity of 10³⁴ 〖 cm〗⁻² s⁻¹ will be achieved through so-called ’magnetized electron cooling’, where the cooling process occurs inside a solenoid field, which will be part of the collider ring and facilitated using a circulator ring and Energy Recovery Linac (ERL). As an initial step, we generated magnetized electron beam using a new compact DC high voltage photogun biased at -300 kV employing an alkali-antimonide photocathode. This contribution presents the characterization of the magnetized electron beam (emittance variations with the magnetic field strength for different laser spot sizes) and a comparison to GPT simulations.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 822
EP  - 825
KW  - solenoid
KW  - emittance
KW  - cathode
KW  - electron
KW  - gun
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-MOPRB110
UR  - http://jacow.org/ipac2019/papers/moprb110.pdf
ER  - 

TY  - CONF
AU  - Solopova, A.D.
AU  - Carpenter, A.
AU  - Iftekharuddin, K.M.
AU  - Powers, T.
AU  - Roblin, Y.
AU  - Tennant, C.
AU  - Vidyaratne, L.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - SRF Cavity Fault Classification Using Machine Learning at CEBAF
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - The Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab is the first large high power CW recirculating electron accelerator which makes use of SRF accelerating structures configured in two antiparallel linacs. Each linac consists of twenty C20/C50 cryomodules each containing eight 5-cell cavities and five C100 upgrade cryomodules each containing eight 7-cell cavities. Accurately classifying the source of cavity faults is critical for improving accelerator performance. In addition to archived signals sampled at 10 Hz, a cavity fault triggers a waveform acquisition process where 16 waveform records sampled at 5 kHz are recorded for each of the 8 cavities in the effected cryomodule. The waveform record length is sufficiently long for transient microphonic effects to be observable. Significant time is required by a subject matter expert to analyze and identify the intra-cavity signatures of imminent faults. This paper describes a path forward that utilizes machine learning for automatic fault classification. Post-training identification of the physical origins of faults are discussed, as are potential machine-trained model-free implementations of trip avoidance procedures. These methods should provide new insights into cavity fault mechanisms and facilitate intelligent optimization of cryomodule performance
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 1167
EP  - 1170
KW  - cavity
KW  - cryomodule
KW  - SRF
KW  - operation
KW  - GUI
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-TUXXPLM2
UR  - http://jacow.org/ipac2019/papers/tuxxplm2.pdf
ER  - 

TY  - CONF
AU  - Kaabi, W.
AU  - Angal-Kalinin, D.
AU  - Bogacz, S.A.
AU  - Bousson, S.
AU  - Brüning, O.S.
AU  - Calaga, R.
AU  - Chaikovska, I.
AU  - Dassa, L.
AU  - Gerigk, F.
AU  - Hounsell, B.
AU  - Hutton, A.
AU  - Jensen, E.
AU  - Klein, M.
AU  - Levichev, E.B.
AU  - Longuevergne, D.
AU  - Marhauser, F.
AU  - McKenzie, J.W.
AU  - Militsyn, B.L.
AU  - Olivier, G.
AU  - Olry, G.
AU  - Pupkov, Yu.A.
AU  - Rimmer, R.A.
AU  - Stocchi, A.
AU  - Tennant, C.
AU  - Thonet, P.A.
AU  - Vallerand, C.
AU  - Welsch, C.P.
AU  - Williams, P.H.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - PERLE: A High Power Energy Recovery Facility
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - PERLE is a proposed high power Energy Recovery Linac, designed on multi-turn configuration, based on SRF technology, to be hosted at Orsay-France in a col-laborative effort between local laboratories: LAL and IPNO, together with an international collaboration involv-ing today: CERN, JLAB, STFC ASTeC Daresbury, Liverpool University and BINP Novosibirsk. PERLE will be a unique leading edge facility designed to push advances in accelerator technology, to provide intense and highly flexible test beams for component development. In its final configuration, PERLE provides a 500 MeV elec-tron beam using high current (20 mA) acceleration during three passes through 801.6 MHz cavities. This presenta-tion outlines the technological choices, the lattice design and the main component descriptions.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 1396
EP  - 1399
KW  - cavity
KW  - linac
KW  - cryomodule
KW  - injection
KW  - gun
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-TUPGW008
UR  - http://jacow.org/ipac2019/papers/tupgw008.pdf
ER  - 

TY  - CONF
AU  - Glock, H.-W.
AU  - Dürr, V.
AU  - Glöckner, F.
AU  - Guo, J.
AU  - Knobloch, J.
AU  - Rimmer, R.A.
AU  - Tannert, M.
AU  - Vélez, A.V.
AU  - Wang, H.
AU  - Wolk, D.
AU  - Wunderer, N.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - Progress of the BESSY VSR Cold String Development and Testing
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - The so-called VSR (Variable Storage Ring) upgrade of the 3rd gen. light source BESSY II will provide the capability to simultaneously store long (about 20 ps rms length) and short (1 ps or less) bunches in the ring. This will be accomplished by inserting a module with four superconducting cavities, two of them operating at 1.5 GHz as the third harmonic of the 500 MHz driving RF, two at 1.75 GHz. The "cold" string of those four cavities also includes supporting and connecting devices, as there will be: - three intermediate bellows, all shielded against leaking fundamental mode cavity fields, one additionally acting as a collimator for incident synchrotron light; - two tuneable bellows at the module ends; - two warm end groups outside the module, housing toroidal dielectric wake field absorbers, another bellow and a vacuum pump connection. The recent design progress of those components will be reported, including a description of a beam test planned for the central collimating shielded bellow.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 1434
EP  - 1436
KW  - cavity
KW  - GUI
KW  - simulation
KW  - experiment
KW  - vacuum
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-TUPGW019
UR  - http://jacow.org/ipac2019/papers/tupgw019.pdf
ER  - 

TY  - CONF
AU  - Bogacz, S.A.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - Multi-pass ERL in a ’Dogbone’ Topology
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - The main thrust of a multi-pass RLA is its very efficient usage of expensive linac structures. That efficiency can be further enhanced by configuring an RLA in a ’dogbone’ topology, which further boosts the RF efficiency by factor of two (compare to a corresponding racetrack). However, the ’dogbone’ configuration requires the beam to traverse the linac in both directions, while being accelerated. This can be facilitated by a special ’bisected’ linac Optics. Here, the quadrupole gradients scale up with momentum to maintain periodic FODO structure for the lowest energy pass in the first half of the linac and then the quadrupole strengths are mirror reflected in the second linac half. The virtue of this optics is the appearance of distinct nodes in the beta beat-wave at the ends of each pass (where the droplet arcs begin), which limits the growth of initial betas at the beginning of each subsequent droplet arc. Furthermore, ‘bisected’ linac optics naturally supports energy recovery in the ’dogbone’ topology. In this paper, we present a-proof-of-principle lattice design of a multi-pass ’dogbone’ ERL.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 1601
EP  - 1603
KW  - linac
KW  - optics
KW  - cavity
KW  - dipole
KW  - focusing
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-TUPGW084
UR  - http://jacow.org/ipac2019/papers/tupgw084.pdf
ER  - 

TY  - CONF
AU  - Zhang, Y.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - JLEIC: A High Luminosity Polarized Electron-Ion Collider at Jefferson Lab
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - The recent National Academies of Science Review concluded the science questions that could be answered by an electron-ion collider are significant to advancing our understanding of the atomic nuclei that make up all visible matter in the universe. To meet this science need, a high luminosity polarized electron-ion collider (JLEIC) was envisioned at Jefferson Lab, based on the existing CEBAF recirculated SRF electron linac. Over the past 16 years, Jefferson Lab has been actively engaged in the design study and accelerator R&D for JLEIC, a comprehensive Pre-Conceptual Design Report has been completed recently. The JLEIC baseline design has also been continuously optimized including extending the CM energy to 100 GeV. In this paper, we present a summary of the JLEIC baseline design and also briefly discuss the accelerator R&D.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 1916
EP  - 1919
KW  - electron
KW  - collider
KW  - luminosity
KW  - proton
KW  - emittance
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-TUPRB112
UR  - http://jacow.org/ipac2019/papers/tuprb112.pdf
ER  - 

TY  - CONF
AU  - Nosochkov, Y.M.
AU  - Cai, Y.
AU  - Lin, F.
AU  - Morozov, V.S.
AU  - Zhang, Y.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - Dynamic Aperture of JLEIC Electron Collider Ring with Errors and Correction
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - Design of the Jefferson Lab Electron-Ion Collider (JLEIC) includes low-beta Interaction Region (IR) and spin rotator optics for high luminosity and polarization. Magnet errors, especially in the high-beta final focus quadrupoles, result in optics perturbations which need to be corrected in order to attain sufficient dynamic aperture (DA). We present design of orbit correction system for the electron ring and evaluate its performance. The DA is then studied including misalignment, magnet strength errors, non-linear field errors, and corrections.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 1920
EP  - 1923
KW  - alignment
KW  - electron
KW  - multipole
KW  - optics
KW  - quadrupole
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-TUPRB113
UR  - http://jacow.org/ipac2019/papers/tuprb113.pdf
ER  - 

TY  - CONF
AU  - Hannon, F.E.
AU  - Andonian, G.
AU  - Harris, L.H.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - A Plasmonic Niobium Photocathode for SRF Gun Applications
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - The typical quantum efficiency of niobium is of the order 10⁻⁴, whilst also requiring UV lasers for emission. This paper presents the results of a plasmonic niobium surface that operates with IR laser via multiphoton emission.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 2079
EP  - 2082
KW  - cathode
KW  - gun
KW  - laser
KW  - cavity
KW  - photon
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-TUPTS069
UR  - http://jacow.org/ipac2019/papers/tupts069.pdf
ER  - 

TY  - CONF
AU  - Hannon, F.E.
AU  - Rimmer, R.A.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - A Normal Conducting RF Gun as an Electron Source for JLEIC Cooling
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - The baseline design for a magnetized injector for the bunched-beam electron cooler ring, as part of the Jeffer-son Lab Electron Ion Collider (JLEIC) uses a DC photo-cathode electron gun as the source. A challenging aspect of this concept is transporting a 3.2nC electron bunch at low energy and preserving the angular momentum. An RF gun source has been investigated to gauge the potential advantages of high gradient on the photocathode and higher exit energy. The design is presented and compared with the baseline results.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 2127
EP  - 2129
KW  - gun
KW  - emittance
KW  - electron
KW  - cathode
KW  - solenoid
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-TUPTS088
UR  - http://jacow.org/ipac2019/papers/tupts088.pdf
ER  - 

TY  - CONF
AU  - Stefani, M.S.
AU  - Gulliford, C.M.
AU  - Hannon, F.E.
AU  - Kostroun, V.O.
AU  - Mayes, C.E.
AU  - Poelker, M.
AU  - Smolenski, K.W.
AU  - Suleiman, R.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - Magnetized Gridded Thermionic Electron Source
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - The study of magnetized electron beam has become a high priority for its use in ion beam cooling as part of Electron Ion Colliders and the potential of easily forming flat beams for various applications. The demand for high average current for effective ion beam cooling has caused consideration of using bunched magnetized electron beam produced by a gridded thermionic electron gun. This paper presents the design of a potential electron source for JCIEC first measurements characterizing the beam properties of a magnetized thermionic gun.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 2140
EP  - 2143
KW  - electron
KW  - gun
KW  - cathode
KW  - emittance
KW  - simulation
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-TUPTS093
UR  - http://jacow.org/ipac2019/papers/tupts093.pdf
ER  - 

TY  - CONF
AU  - Zhang, S.
AU  - Adderley, P.A.
AU  - Benesch, J.F.
AU  - Bullard, D.B.
AU  - Delayen, J.R.
AU  - Grames, J.M.
AU  - Guo, J.
AU  - Hannon, F.E.
AU  - Hansknecht, J.
AU  - Hernandez-Garcia, C.
AU  - Kazimi, R.
AU  - Krafft, G.A.
AU  - Mamun, M.A.
AU  - Poelker, M.
AU  - Suleiman, R.
AU  - Tiefenback, M.G.
AU  - Wang, Y.W.
AU  - Wijethunga, S.A.K.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - High Current High Charge Magnetized and Bunched Electron Beam from a DC Photogun for JLEIC Cooler
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - A high current, high charge magnetized electron beamline that has been under development for fast and efficient cooling of ion beams for the proposed Jefferson Lab Electron Ion Collider (JLEIC). In this paper, we present the latest progress over the past year that include the generation of picosecond magnetized beam bunches at average currents up to 28 mA with exceptionally long photocathode lifetime, and the demonstrations of magnetized beam with high bunch charge up to 700 pC at 10s of kHz repetition rates. Detailed studies on a stable drive laser system, long lifetime photocathode, beam magnetization effect, beam diagnostics, and a comparison between experiment and simulations will also be reported. These accomplishes marked an important step towards the essential feasibility for the JLEIC cooler design using magnetized beams.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 2167
EP  - 2170
KW  - cathode
KW  - laser
KW  - electron
KW  - gun
KW  - emittance
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-TUPTS105
UR  - http://jacow.org/ipac2019/papers/tupts105.pdf
ER  - 

TY  - CONF
AU  - Wang, H.
AU  - Coriton, B.R.L.
AU  - Dudas, A.
AU  - Moeller, C.P.
AU  - Nelson, R.M.
AU  - Neubauer, M.L.
AU  - Rimmer, R.A.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - Magnetron R&D for High Efficiency CW RF Sources of Particle Accelerators
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - The scheme of using a high efficiency magnetron to drive a superconducting or normal conducting radio frequency accelerator cavity needs not only injection phase locking but also amplitude modulation to compensate for the cavity’s microphonics, frequency change, variations of cavity voltage and beam current. To be able to do a fast and efficient modulation and to compensate the frequency pushing effect due to the anode current change, the magnetron’s magnetic field has to be trimmed by an external coil*. To facilitate this, a low eddy current magnetron body has been designed and built**. This paper will present the experimental results of such modulation on a conventional 2.45 GHz magnetron at the R&D test stand. In addition, the progresses on the injection lock test to a new 1497 MHz, 13kW magnetron prototype aimed for the CEBAF klystron replacement with newly built low level RF (LLRF) controller for the amplitude modulation will be reported. Based on these R&D results, a 915MHz, 2×75kW CW industrial heating type magnetron system is being developed to be used for the high efficiency (>80%) RF source to the electron accelerator for industrial applications.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 2233
EP  - 2236
KW  - injection
KW  - cavity
KW  - electron
KW  - controls
KW  - klystron
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-WEXXPLS1
UR  - http://jacow.org/ipac2019/papers/wexxpls1.pdf
ER  - 

TY  - CONF
AU  - Kazimi, R.
AU  - Freyberger, A.
AU  - Grames, J.M.
AU  - Hansknecht, J.
AU  - Hofler, A.S.
AU  - Plawski, T.E.
AU  - Poelker, M.
AU  - Spata, M.F.
AU  - Wang, Y.W.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - Operational Results of Simultaneous Four-Beam Delivery at Jefferson Lab
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - A concept for simultaneous beam delivery to all four CEBAF experimental halls from a single injector and a single main accelerator for the 12 GeV era was proposed in 2012. The original 12 GeV beam delivery plan was for a maximum of three experimental halls at a time as in the 6 GeV era. Therefore, the new concept increases the po-tential beam time for the experiments up to 33%. This change, although a major improvement in operational capabilities, required only limited modifications to the existing machine. The modifications were mainly timing and pattern changes to the beams in the injector, adding a fourth laser to the photo-cathode gun, and the addition of new RF separators to the highest pass of CEBAF. These changes are now complete and, for the first time, the full system is operating, producing four simultaneous beams through the accelerator to four different destinations. In this paper, in addition to presenting the results of the full system commissioning, we will discuss important details about the new configuration plus some of our operational challenges.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 2454
EP  - 2457
KW  - laser
KW  - operation
KW  - experiment
KW  - cavity
KW  - gun
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-WEPMP053
UR  - http://jacow.org/ipac2019/papers/wepmp053.pdf
ER  - 

TY  - CONF
AU  - Stefani, M.S.
AU  - Hannon, F.E.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - Transverse Uncorrelated Emittance Diagnostic for Magnetized Electron Beams
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - The study of magnetized electron beam has become a high priority for its use in ion beam cooling as part of Electron Ion Colliders and the potential of easily forming flat beams for various applications. In this paper, a new diagnostic is described with the purpose of studying transverse magnetized beam properties. The device is a modification to the classic pepper-pot, used in this novel context to measure the uncorrelated components of transverse emittance in addition to the typical effective emittance. The limitations of traditional methods are discussed, and simulated demonstrations of the new technique shown.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 2745
EP  - 2748
KW  - emittance
KW  - electron
KW  - diagnostics
KW  - simulation
KW  - cathode
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-WEPGW108
UR  - http://jacow.org/ipac2019/papers/wepgw108.pdf
ER  - 

TY  - CONF
AU  - Stefani, M.S.
AU  - Park, G.-T.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - Double Quarter Wave Deflector Cavity Design & Simulation
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - A Double Quarter Wave (DQW) Cavity has been designed, tested and installed for use in longitudinal measurements as part of a diagnostic beamline. This report will describe the design and testing used to characterize this cavity before its use in the study of a magnetized electron beam.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 2749
EP  - 2751
KW  - cavity
KW  - coupling
KW  - operation
KW  - simulation
KW  - diagnostics
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-WEPGW109
UR  - http://jacow.org/ipac2019/papers/wepgw109.pdf
ER  - 

TY  - CONF
AU  - Lin, F.
AU  - Cai, Y.
AU  - Morozov, V.S.
AU  - Nosochkov, Y.M.
AU  - Zhang, Y.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - Update on the JLEIC Electron Collider Ring Design
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - The design concept of electron collider ring in the Jefferson Lab Electron-Ion Collider (JLEIC) is based on a small beam size at the interaction point (IP) to boost the luminosity. With a chosen beta-star at the IP, electron beam size is determined by the equilibrium emittance obtained from the linear optics design. In this paper, we present an update on the lattice design of the electron ring considering not only preservation of low beam emittance, but also optimization of geometric arrangement. In particular, recent development of the lattice design has been focused on incorporating the vertical dogleg, which brings the electron beam to the ion beam plane for collisions, in the spin rotator design. The vertical dogleg is designed with no horizontal emittance growth, controlled vertical emittance and no first-order effect on the electron polarization.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 2780
EP  - 2782
KW  - electron
KW  - collider
KW  - optics
KW  - quadrupole
KW  - solenoid
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-WEPGW121
UR  - http://jacow.org/ipac2019/papers/wepgw121.pdf
ER  - 

TY  - CONF
AU  - Morozov, V.S.
AU  - Adams, P.
AU  - Derbenev, Y.S.
AU  - Filatov, Y.
AU  - Huang, H.
AU  - Kondratenko, A.M.
AU  - Kondratenko, M.A.
AU  - Lin, F.
AU  - Méot, F.
AU  - Ptitsyn, V.
AU  - Schmidke, W.B.
AU  - Zhang, Y.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - EXPERIMENTAL VERIFICATION OF TRANSPARENT SPIN MODE IN RHIC
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - High electron and ion polarizations are some of the key design requirements of a future Electron Ion Collider (EIC). The transparent spin mode, a concept inspired by the figure 8 ring design of JLEIC, is a novel technique for preservation and control of electron and ion spin polarizations in a collider or storage ring. It makes the ring lattice "invisible" to the spin and allows for polarization control by small quasi-static magnetic fields with practically no effect on the beam’s orbital characteristics. It offers unique opportunities for polarization maintenance and control in Jefferson Lab’s JLEIC and in BNL’s eRHIC. The transparent spin mode has been demonstrated in simulations and we now plan to test it experimentally. We present a design of an experiment using a polarized proton beam stored in one of the RHIC rings. In the experiment, one of the RHIC rings is configured in the transparent spin mode by aligning the axes of its two Siberian snakes. The experiment goals, procedures, hardware requirements and expected results are presented.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 2783
EP  - 2786
KW  - polarization
KW  - collider
KW  - controls
KW  - experiment
KW  - resonance
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-WEPGW122
UR  - http://jacow.org/ipac2019/papers/wepgw122.pdf
ER  - 

TY  - CONF
AU  - Morozov, V.S.
AU  - Cai, Y.
AU  - Ent, R.
AU  - Furletova, Y.
AU  - Lin, F.
AU  - Michalski, T.J.
AU  - Nosochkov, Y.M.
AU  - Rajput-Ghoshal, R.
AU  - Sabbi, G.L.
AU  - Sullivan, M.K.
AU  - Wiseman, M.
AU  - Yoshida, R.
AU  - Zhang, Y.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - Full Acceptance Interaction Region Design of JLEIC
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - Nuclear physics experiments envisioned at a proposed future Electron-Ion Collider (EIC) require high luminosity of 10³³-10³⁴ cm⁻²s⁻¹ and a full-acceptance detector capable of reconstruction of a whole electron-ion collision event. Due to a large asymmetry in the electron and ion momenta in an EIC, the particles associated with the initial ion tend to go at very small angles and have small rigidity offsets with respect to the initial ion beam. They are detected after they pass through the apertures of the final focusing quadrupoles. Therefore, the apertures must be sufficiently large to provide the acceptance required by experiments. In addition, to maximize the luminosity, the final focusing quadrupoles must be placed as close to the interaction point as possible. A combination of these requirements presents serious detection, optics and engineering design challenges. We present a design of a full-acceptance interaction region of Jefferson Lab Electron-Ion Collider (JLEIC). The paper presents how this design addresses the above requirements up to an ion momentum of 200 GeV/c. We summarize the magnet parameters, which are kept consistent with the Nb-Ti superconducting magnet technology.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 2787
EP  - 2790
KW  - electron
KW  - detector
KW  - dipole
KW  - coupling
KW  - interaction-region
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-WEPGW123
UR  - http://jacow.org/ipac2019/papers/wepgw123.pdf
ER  - 

TY  - CONF
AU  - Morozov, V.S.
AU  - Adams, P.
AU  - Derbenev, Y.S.
AU  - Filatov, Y.
AU  - Huang, H.
AU  - Kondratenko, A.M.
AU  - Kondratenko, M.A.
AU  - Lin, F.
AU  - Méot, F.
AU  - Ptitsyn, V.
AU  - Schmidke, W.B.
AU  - Zhang, Y.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - Spin Response Function for Spin Transparency Mode of RHIC
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 Spin Transparency (ST) mode of RHIC, the axes of its Siberian snakes are parallel. The spin tune in the ST mode is zero and the spin motion becomes degenerate: any spin direction repeats every particle turn. In contrast, the lattice of a conventional collider determines a unique stable periodic spin direction, so that the collider operates in the Preferred Spin (PS) mode. Contributions of perturbing magnetic fields to the spin resonance strengths in the PS mode are usually calculated using the spin response function. However, in that form, it is not applicable in the ST mode. This paper presents a response function formalism expanded for the ST mode of operation of conventional colliders with two identical Siberian snakes in the highly-relativistic limit. We present calculations of the spin response function for RHIC in the ST mode.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 2791
EP  - 2793
KW  - resonance
KW  - collider
KW  - polarization
KW  - controls
KW  - lattice
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-WEPGW124
UR  - http://jacow.org/ipac2019/papers/wepgw124.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  - De Silva, S.U.
AU  - Delayen, J.R.
AU  - Morozov, V.S.
AU  - Park, H.
AU  - Sosa, S.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - Analysis of Higher Order Multipoles of  the 952.6 Mhz RF-Dipole Crabbing Cavity for the Jefferson Lab Electron-Ion Collider
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - The crabbing system is a key feature in the Jefferson Lab Electron-Ion Collider (JLEIC) required to increase the luminosity of the colliding bunches. A local crabbing system will be installed with superconducting rf-dipole crabbing cavities operating at 952.6 MHz. The field non-uniformity across the beam aperture in the crabbing cavities produces higher order multipole components, similar to that which are present in magnets. Knowledge of higher order mode multipole field effects is important for accurate beam dynamics study for the crabbing system. In this paper, we quantify the multipole components and analyse their effects on the beam dynamics.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 2996
EP  - 2998
KW  - cavity
KW  - multipole
KW  - dipole
KW  - HOM
KW  - electron
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-WEPRB076
UR  - http://jacow.org/ipac2019/papers/weprb076.pdf
ER  - 

TY  - CONF
AU  - Park, H.
AU  - De Silva, S.U.
AU  - Delayen, J.R.
AU  - Sosa Guitron, S.I.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - Design of a Proof-of-principle Crabbing Cavity for the Jefferson Lab Electron-ion Collider
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - The Jefferson Lab design for an electron-ion collider (JLEIC) requires crabbing of the electron and ion beams in order to achieve the design luminosity. A number of options for the crabbing cavities have been explored, and the one which has been selected for the proof-of-principle is a 952 MHz, 2-cell rf-dipole (RFD) cavity. This paper summarizes the electromagnetic design of the cavity and its HOM characteristics.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 3027
EP  - 3030
KW  - cavity
KW  - electron
KW  - HOM
KW  - collider
KW  - luminosity
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-WEPRB093
UR  - http://jacow.org/ipac2019/papers/weprb093.pdf
ER  - 

TY  - CONF
AU  - Geng, R.L.
AU  - Freyberger, A.
AU  - Rimmer, R.A.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - Understanding and Mitigation of Field Emission in CEBAF SRF Linacs
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - We will present current understanding of field emission in two 1.1 GeV CW SRF linacs at CEBAF and its mitigation for improved CEBAF energy reach and operation reliability. This contribution will provide a review of CEBAF gradient evolution since 2014, the impact of field emission, the effort in understanding the root cause of field emission in operational SRF cavities including the recently installed C100 cavities. We will evaluate the effect of initial mitigations implemented since 2016, aimed at reducing generation and transportation of new field emitting particulates. Effects of cavity thermal cycling aimed at abating activation of settled field emitting particulates will be evaluated as well. Remaining issues toward predictable control of field emission in operational SRF cavities will be discussed.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 3039
EP  - 3042
KW  - cavity
KW  - cryomodule
KW  - linac
KW  - operation
KW  - vacuum
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-WEPRB097
UR  - http://jacow.org/ipac2019/papers/weprb097.pdf
ER  - 

TY  - CONF
AU  - Verdú-Andrés, S.
AU  - Ben-Zvi, I.
AU  - Burt, G.
AU  - Calaga, R.
AU  - Capatina, O.
AU  - Huque, N.A.
AU  - Li, Z.
AU  - McEwen, E.A.
AU  - Mitchell, J.A.
AU  - Park, H.
AU  - Powers, T.
AU  - Ratti, A.
AU  - Wu, Q.
AU  - Xiao, B.P.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - Cryogenic RF Performance of Double-Quarter Wave Cavities Equipped with HOM Filters
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - Crab cavities are one of the several components included in the luminosity upgrade of the Large Hadron Collider (HL-LHC). The cavities have to provide a nominal deflecting kick of 3.4 MV per cavity while the cryogenic load per cavity stays below 5 W. Cold RF tests confirmed the required performances in bare cavities, with several cavities exceeding the required voltage by more than 50%. However, the first tests of a Double-Quarter Wave (DQW) cavity with one out of three HOM filters did not reach the required voltage. The present paper describes the studies and tests conducted on a DQW cavity with HOM filter to understand the limiting factor. The recipe to meet the performance specification and exceed the voltage requirement by more than 35% is discussed.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 3043
EP  - 3046
KW  - cavity
KW  - HOM
KW  - operation
KW  - cryogenics
KW  - SRF
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-WEPRB098
UR  - http://jacow.org/ipac2019/papers/weprb098.pdf
ER  - 

TY  - CONF
AU  - Park, G.-T.
AU  - Guo, J.
AU  - Henry, J.
AU  - Marchlik, M.
AU  - Marhauser, F.
AU  - Rimmer, R.A.
AU  - Wang, H.
AU  - Wang, S.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - Status Update of a Harmonic Kicker Development for JLEIC
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - An effort to develop the second prototype of the harmonic kicker for the Circulator Cooler Ring (CCR) of the Jefferson Lab Electron-Ion Collider (JLEIC) is under way. After beam dynamics studies and completion of a conceptual RF design of the kicker [1], further progress has been made toward the final mechanical design including the input power coupler (loop) design, tuner ports, multipacting studies. Furthermore, concerning the kicker’s compatibility with beam dynamics, the impact of RF multipole components was investigated and a scheme was developed to cancel out detrimental beam effects.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 3047
EP  - 3050
KW  - kicker
KW  - multipole
KW  - cavity
KW  - coupling
KW  - simulation
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-WEPRB099
UR  - http://jacow.org/ipac2019/papers/weprb099.pdf
ER  - 

TY  - CONF
AU  - Pudasaini, U.
AU  - Ciovati, G.
AU  - Eremeev, G.V.
AU  - Kelley, M.J.
AU  - Parajuli, I.P.
AU  - Reece, C.E.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - Recent Results from Nb₃Sn-Coated Single-cell Cavities Combined with Sample Studies at Jefferson Lab
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - The critical temperature (~ 18 K) and superheating field (~ 425 mT) of Nb₃Sn are almost twice that of niobium, thereby promising the higher quality factor and accelerating gradient at any given temperature compared to traditional SRF cavities made of niobium. It can enable higher temperature for cavity operation (4 K Vs. 2 K), resulting in significant reduction in both capital and operating cost for the cryoplant. Several single-cell cavities along with witness samples were coated with Nb₃Sn to explore, understand and improve the coating process for betterment of cavity performance. RF measurements of coated cavities combined with material characterization of witness samples were employed to update the coating process. Following some modifications to the existing coating process, we were able to produce Nb₃Sn cavity with quality factor ≥ 2.10¹⁰ for accelerating gradient up to 15 MV/m at 4 K, without any significant Q-slope. In this article, we will discuss recent results from several Nb₃Sn coated single-cell cavities combined with material studies of witness samples.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 3066
EP  - 3069
KW  - cavity
KW  - experiment
KW  - SRF
KW  - superconductivity
KW  - niobium
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-WEPRB110
UR  - http://jacow.org/ipac2019/papers/weprb110.pdf
ER  - 

TY  - CONF
AU  - Eremeev, G.V.
AU  - Pudasaini, U.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - Development of Nb₃Sn Multicell Cavity Coatings
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - Nb₃Sn films have the potential to augment niobium in SRF cavities. Besides single-cell cavity efforts to improve Nb₃Sn films, we are working to replicate single-cell results onto the practical 5-cell CEBAF cavities. High quality factors (10¹¹ at 2.0K and 10^{z}EhNZeHn at 4.3 K) have been measured, but the cavities are typically limited by strong low-field Q-slopes and early quenches. Two of the cavities were selected to be assembled into a ’mock-up’ cavity pair unit, the standard step before installation into a cryomodule. Comparison of test results between VTA and pair test offered the first glimpse into post-processing effects on the cavity performance.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 3070
EP  - 3073
KW  - cavity
KW  - niobium
KW  - HOM
KW  - factory
KW  - cryomodule
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-WEPRB111
UR  - http://jacow.org/ipac2019/papers/weprb111.pdf
ER  - 

TY  - CONF
AU  - Bafia, D.
AU  - Checchin, M.
AU  - Gonnella, D.
AU  - Grassellino, A.
AU  - Martinello, M.
AU  - Melnychuk, O.S.
AU  - Palczewski, A.D.
AU  - Posen, S.
AU  - Romanenko, A.S.
AU  - Sergatskov, D.A.
AU  - Zasadzinski, J.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - Understanding and Pushing the Limits of Nitrogen Doping
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - This work will describe Fermilab experiments that focus on the optimization of doping parameters to achieve low sensitivity to trapped magnetic flux while maintaining very high Q characteristic of nitrogen doped cavities and same or higher quench fields. Working partially in the context of LCLS-2 higher energy upgrade, new doping recipes are pursued and have been found to vary the mean free path of the resonator which is related to the sensitivity to trapped magnetic flux. Moreover, a correlation has been found between lighter doping and higher quench fields while maintaining sufficiently low surface resistance.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 3078
EP  - 3081
KW  - cavity
KW  - SRF
KW  - niobium
KW  - experiment
KW  - ECR
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-WEPRB114
UR  - http://jacow.org/ipac2019/papers/weprb114.pdf
ER  - 

TY  - CONF
AU  - Huang, H.
AU  - Lin, F.
AU  - Morozov, V.S.
AU  - Neththikumara, I.
AU  - Roblin, Y.
AU  - Sosa, S.
AU  - Sy, A.V.
AU  - Terzić, B.
AU  - Zhang, Y.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - Beam-Beam Effect: Crab Dynamics Calculation in JLEIC
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - The electron and ion beams of a future Electron Ion Collider (EIC) must collide at an angle for detection, machine and engineering design reasons. To avoid associated luminosity reduction, a local crabbing scheme is used where each beam is crabbed before collision and de-crabbed after collision. The crab crossing scheme then provides a head-on collision for beams with a non-zero crossing angle. We develop a framework for accurate simulation of crabbing dynamics with beam-beam effects by combining symplectic particle tracking codes with a beam-beam model based on the Bassetti-Erskine analytic solution. We present simulation results using our implementation of such a framework where the beam dynamics around the ring is tracked using Elegant and the beam-beam kick is modeled in Python.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 3293
EP  - 3296
KW  - simulation
KW  - luminosity
KW  - collider
KW  - electron
KW  - cavity
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-WEPTS073
UR  - http://jacow.org/ipac2019/papers/wepts073.pdf
ER  - 

TY  - CONF
AU  - Nissen, E.A.
AU  - Schulte, D.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - An Analytic Approach to Emittance Growth from the Beam-Beam Effect with Applications to the LHeC
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - In colliders with asymmetric rigidity such as the proposed Large Hadron electron Collider, jitter in the weaker beam can cause emittance growth via coherent beam-beam interactions. The LHeC in this case would collide 7 TeV protons on 60 GeV electrons, which can be modeled using a weak-strong model. In this work we estimate the proton beam emittance growth by separating out the longitudinal angular kicks from an off-center bunch interaction and produce an analytic expression for the emittance growth per turn in systems like the LHeC.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 3307
EP  - 3310
KW  - proton
KW  - emittance
KW  - electron
KW  - GUI
KW  - collider
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-WEPTS081
UR  - http://jacow.org/ipac2019/papers/wepts081.pdf
ER  - 

TY  - CONF
AU  - Nissen, E.A.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - Luminosity Studies of Asymmetric Crab Crossing in JLEIC
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - The proposed Jefferson Lab Electron Ion Collider (JLE-IC) currently plans to use a crab crossing scheme to max-imize the available luminosity. It had been suggested that space and cost savings, as well as hadron beam quality improvements, could be realized by leaving the ion beam un-crabbed and increasing the crabbing angle of the elec-tron beam. This and variations in-between equal and totally one-sided crabbing are examined for both JLEIC and LHC parameters, with various changes in crabbing angle and frequency studied to maximize luminosity.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 3311
EP  - 3312
KW  - luminosity
KW  - ECR
KW  - collider
KW  - electron
KW  - cavity
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-WEPTS082
UR  - http://jacow.org/ipac2019/papers/wepts082.pdf
ER  - 

TY  - CONF
AU  - Liu, F.
AU  - Huang, S.
AU  - Liu, K.X.
AU  - Zhang, S.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - Highly Stable Linearly Polarized Arbitrary Temporal Shaping of Picosecond Laser Pulses
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - This paper reports the study and demonstration of a new variable temporal shaping method capable of generating linearly polarized picosecond laser pulses with arbitrary predefined shapes, which are highly desired by various applications including low emittance high brightness electron bunch generation in photocathode guns. It is found that both high transmittance and high stability of the shaped pulses can be achieved simultaneously when crystals are set at specific phase delay through the fine control of the crystal temperature. Such variable temporal shaping technique may lead to new opportunities for many potential applications over a wide range of laser wavelengths, pulse repetition rates, time structures and power levels, etc. In addition, a new double-pass variable shaping method is also proposed and could significantly simplify the shaper structure and reduce the cost.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 3682
EP  - 3685
KW  - laser
KW  - controls
KW  - polarization
KW  - experiment
KW  - flattop
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-THPGW044
UR  - http://jacow.org/ipac2019/papers/thpgw044.pdf
ER  - 

TY  - CONF
AU  - Neubauer, M.L.
AU  - Cummings, M.A.
AU  - Dudas, A.
AU  - Johnson, R.P.
AU  - Kahn, S.A.
AU  - Kazakevich, G.M.
AU  - Popovic, M.
AU  - Rimmer, R.A.
AU  - Wang, H.
ED  - Boland, Mark
ED  - Tanaka, Hitoshi
ED  - Button, David
ED  - Dowd, Rohan
ED  - Schaa, Volker RW
ED  - Tan, Eugene
TI  - Injection Locked 1497 MHz Magnetron
J2  - Proc. of IPAC2019, Melbourne, Australia, 19-24 May 2019
CY  - Melbourne, Australia
T2  - International Particle Accelerator Conference
T3  - 10
LA  - english
AB  - Muons, In is building an amplitude modulated phase-locked magnetron to replace the klystrons in CEBAF. To do that requires changing the magnetic field at a rate that would induce eddy currents in the standard magnetron. We report on the status of the project to make a stainless steel anode with copper elements to minimize heating while the stainless steel reduces eddy current effects. The construction of the magnetron is two months from completion, while the test stand is ready for delivery of the magnetron
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 4322
EP  - 4324
KW  - klystron
KW  - status
KW  - cathode
KW  - operation
KW  - injection
DA  - 2019/06
PY  - 2019
SN  - 978-3-95450-208-0
DO  - DOI: 10.18429/JACoW-IPAC2019-THPTS090
UR  - http://jacow.org/ipac2019/papers/thpts090.pdf
ER  -