THPO —  Thursday Poster Session   (20-Sep-18   16:00—18:00)
Paper Title Page
THPO001 Design Study on CEPC Positron Damping Ring System 672
 
  • D. Wang, Y.L. Chi, J. Gao, D.J. Gong, C. Meng, G. Pei, J.R. Zhang
    IHEP, Beijing, People’s Republic of China
  
  The pri­mary pur­pose of CEPC damp­ing ring is to re­duce the trans­verse phase spaces of positron beam to suit­ably small value at the be­gin­ning of linac and hence re­duce the beam loss in the booster. Be­fore damp­ing ring, an en­ergy spread com­pres­sion struc­ture is de­signed to match the RF ac­cep­tance of damp­ing ring. A lon­gi­tu­di­nal bunch length con­trol is also nec­es­sary to meet the en­ergy spread re­quire­ment in the linac by a bunch com­pres­sor sys­tem after the damp­ing ring. Both de­signs for damp­ing ring and en­ergy/bunch com­pres­sors are dis­cussed in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO001  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO002 Investigation of SRF Elliptical Cavities Made by New Nb Materials in KEK 676
 
  • T. Dohmae, K. Umemori, Y. Watanabe, M. Yamanaka
    KEK, Ibaraki, Japan
  • T. Okada
    Sokendai, Ibaraki, Japan
  
  Cost re­duc­tion for cav­ity fab­ri­ca­tion is cur­rently main issue to re­al­ize in­ter­na­tional lin­ear col­lider. Cav­ity fab­ri­ca­tion fa­cil­ity (CFF) in KEK is ap­proach­ing this issue from a point of view of ma­te­ri­als for cav­i­ties. CFF had fab­ri­cated SRF el­lip­ti­cal cav­i­ties made by two types of nio­bium; one is high tan­ta­lum con­tained and low RRR (< 100) fine grain nio­bium, and the other is high tan­ta­lum con­tained and RRR < 300 large grain (LG) nio­bium. For­mer was melted two times (nor­mally five times) which re­sults RRR re­cov­ery up to around 300, and used for cell parts. Two 3-cell cav­i­ties were fab­ri­cated for each ma­te­r­ial re­spec­tively and ver­ti­cal tested. One of these cav­ity made by LG achieved ac­cel­er­a­tor gra­di­ents of more than 40 MV/m. In this re­port, cav­ity ma­te­ri­als and ver­ti­cal test re­sults are pre­sented in de­tail.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO002  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO003 L-band Resonant Ring for Testing RF Windows for ILC 679
SPWR005   use link to see paper's listing under its alternate paper code  
 
  • B. Du, N. Liu
    Sokendai - Hayama, Hayama, Japan
  • T. Matsumoto, S. Michizono, T. Miura, F. Qiu
    KEK, Ibaraki, Japan
  • T. Matsumoto, T. Miura, F. Qiu
    Sokendai, Ibaraki, Japan
  
  A res­o­nant ring is widely used for the break­down test of RF com­po­nents under high power. It can reach power gain of more than 10dB, which is lim­ited by the at­tenua-tion of the ring. An L-band res­o­nant ring is con­structed for test­ing RF com­po­nents of In­ter­na­tional Lin­ear Col­lid-er (ILC) which is based on an RF fre­quency of 1.3GHz. The tar­get of the high power test is 5 MW. We have fin-ished the test of an input power of 500 W using a solid state am­pli­fier, and the prin­ci­ple of the res­o­nant ring is ver­i­fied. The res­o­nant ring is tuned to an op­ti­mal condi-tion, which is prepa­ra­tion for high power op­er­a­tion. This paper de­tails the prin­ci­ple, con­struc­tion, and test of the L-band res­o­nant ring.  
poster icon Poster THPO003 [2.301 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO003  
About • paper received ※ 13 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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THPO004 Pulsed Operation of CEBAF for JLEIC Injection 682
 
  • J. Guo, J.M. Grames, R. Kazimi, F. Lin, T. E. Plawski, R.A. Rimmer, H. Wang
    JLab, Newport News, Virginia, USA
  
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
JLab Elec­tron Ion Col­lider (JLEIC) is plan­ning to use the re­cently up­graded 12 GeV CEBAF 1497 MHz SRF CW re­cir­cu­lat­ing linac as a full-en­ergy in­jec­tor for the elec­tron col­lider ring. The JLEIC elec­tron in­jec­tion re­quires 3-4µs long bunch trains with a 20-400ms spac­ing in be­tween, re­sult­ing in un­even beam load­ing for the CW CEBAF. With the high beam cur­rent in JLEIC col­lider rings, the low duty fac­tor of in­jec­tion also re­quires to a very high pulsed beam cur­rent from CEBAF, ex­ac­er­bat­ing the tran­sient beam load­ing issue. In this paper, we will pre­sent CE­BAFs de­tailed pulsed op­er­a­tion scheme for JLEIC in­jec­tion, as well as some ex­per­i­men­tal re­sults at CEBAF. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO004  
About • paper received ※ 20 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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THPO005 High Aspect Ratio Beam Generation with the Phase-space Rotation Technique for Linear Colliders 685
 
  • M. Kuriki
    HU/AdSM, Higashi-Hiroshima, Japan
  • H. Hayano, X.J. Jin, T. Konomi, Y. Seimiya, N. Yamamoto
    KEK, Ibaraki, Japan
  • S. Kashiwagi
    Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
  • P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • J.G. Power
    ANL, Argonne, Illinois, USA
  • K. Sakaue
    Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan
  • M. Washio
    RISE, Tokyo, Japan
  • H.W. Zhao
    IMP/CAS, Lanzhou, People’s Republic of China
  
  Funding: This work is partly supported by Grant-in-Aid for Scientific Research (B) and US-Japan Science and Technology Cooperation Program in High Energy Physics.
Lin­ear col­lid­ers is the only way to re­al­ize e+ e− col­li­sion at higher en­ergy be­yond the limit of ring col­lid­ers by the huge syn­chro­tron ra­di­a­tion en­ergy loss. In the lin­ear col­lider, the beam cur­rent should be much smaller com­par­ing to the ring col­lider to save the re­quired elec­tric­ity. A way to re­al­ize an enough lu­mi­nos­ity with the small beam cur­rent and less en­ergy spread by Beam­strahlung, is col­li­sion in flat beam. This high as­pect ratio beam can be made by phase-space ro­ta­tion tech­nique in­stead of the con­ven­tional way with DR (Damp­ing Ring). We pre­sent a sim­u­la­tion of this tech­nique and pilot ex­per­i­ments at KEK-STF and ANL WFA. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO005  
About • paper received ※ 12 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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THPO006 Status of 650 MHz SRF Cavity for eRHIC SRF Linac 688
 
  • W. Xu, I. Ben-Zvi, Y. Gao, D. Holmes, P. Kolb, G.T. McIntyre, R. Porqueddu, K.S. Smith, F.J. Willeke, Q. Wu, A. Zaltsman
    BNL, Upton, Long Island, New York, USA
  
  Funding: This work is supported by LDRD program of Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
A 5-cell 650 MHz SRF cav­ity was de­signed for eRHIC SRF linac. One Cu cav­ity was fab­ri­cated for HOM damp­ing study, and one Nb cav­ity was fab­ri­cated for SRF stud­ies. Through var­i­ous post-pro­cess­ing recipes and ver­ti­cal tests, the SRF study in­cludes high Q-value study for ERL SRF linac and high gra­di­ent study for re­cir­cu­lat­ing linac. This paper re­ports the HOM damp­ing mea­sure­ment on the Cu cav­ity and pre­lim­i­nary ver­ti­cal test re­sults. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO006  
About • paper received ※ 22 August 2018       paper accepted ※ 08 October 2018       issue date ※ 18 January 2019  
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THPO007 MESA - Status of the Implementation of the MicroTCA.4-based LLRF Control System 691
 
  • J.N. Bai, K. Aulenbacher, J. Diefenbach, F. Fichtner
    IKP, Mainz, Germany
  • P. Echevarria
    HZB, Berlin, Germany
  • R.G. Heine
    KPH, Mainz, Germany
  
  MESA at the In­sti­tut für Kern­physik (KPH) at Jo­hannes Guten­berg-Uni­ver­sität Mainz is a multi-turn en­ergy re­cov­ery linac (ERL), aim­ing to serve as user fa­cil­ity for par­ti­cle physics ex­per­i­ments. The RF-ac­cel­er­at­ing sys­tems of MESA con­sist of four 9-cell TESLA su­per­con­duct­ing cav­i­ties, four nor­mal con­duct­ing (NC) pre-ac­cel­er­a­tor cav­i­ties, two NC buncher cav­i­ties and two NC chop­per cav­i­ties. They op­er­ate in con­tin­u­ous wave (CW) mode. In order to con­trol the radio fre­quency (RF) am­pli­tude and phase within the 12 cav­i­ties with the re­quired ac­cu­racy and sta­bil­ity in the range of bet­ter than 0.01% and 0.01°, the Mi­croTCA.4 based dig­i­tal low-level RF (LLRF) con­trol sys­tem based on the de­vel­op­ment at DESY, Ham­burg will be well adapted for the MESA cav­i­ties. In this paper, we de­scribe the the­o­ret­i­cal mod­el­ling of su­per­con­duct­ing cav­ity and PID con­troller in SIMULINK which is use­ful to find the suit­able con­trol pa­ra­me­ter for the PID con­troller and to pre­dict the sys­tem per­for­mance. The progress to date of the im­ple­men­ta­tion and tests of the LLRF sys­tem at MESA will also be pre­sented.  
poster icon Poster THPO007 [1.274 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO007  
About • paper received ※ 11 September 2018       paper accepted ※ 09 October 2018       issue date ※ 18 January 2019  
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THPO008 Long-term 0peration with Beam and Cavity Performance Degradation in Compact-ERL Main Linac at KEK 695
 
  • H. Sakai, T. Furuya, E. Kako, T. Konomi, T. Miura, F. Qiu, K. Umemori
    KEK, Ibaraki, Japan
  
  We de­vel­oped ERL main linac cry­omod­ule for Com­pact ERL (cERL) in KEK. The mod­ule con­sists of two 9-cell 1.3 GHz su­per­con­duct­ing cav­i­ties. After con­struc­tion of cERL re­cir­cu­la­tion loop, beam op­er­a­tion was started in 2013 Dec. First elec­tron beam of 20 MeV suc­cess­fully passed the main linac cav­i­ties. Beam cur­rent in­creased step by step and cur­rently reached to 1mA (CW). En­ergy re­cov­ery has suc­cess­fully achieved. How­ever, field emis­sion was one of the prob­lems for long term op­er­a­tion. There­fore, the per­for­mance of the SRF cav­i­ties through long term beam op­er­a­tion has been in­ves­ti­gated. In this paper, we ex­press the mea­sure­ment of the cav­ity per­for­mances and its degra­da­tion dur­ing long term beam op­er­a­tion. We also de­scribed the de­tails of the cav­ity per­for­mance degra­da­tion and some trial for the cav­ity per­for­mance re­cov­ery.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO008  
About • paper received ※ 11 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO009 Evaluation of 60pC Beam Performance at cERL Injector for ERL Based EUV-FEL 699
SPWR001   use link to see paper's listing under its alternate paper code  
 
  • T. Hotei
    Sokendai, Ibaraki, Japan
  • R. Kato, T. Miyajima
    KEK, Ibaraki, Japan
  
  In order to com­pen­sate for the emit­tance which is in­creased by space charge in the low en­ergy re­gion, it is im­por­tant to trans­port the beam as de­signed. Until now, we did not con­sider cou­plers in in­jec­tor su­per­don­duct­ing cav­i­ties in op­tics de­sign. But in this study, to im­prove op­tics match­ing and emit­tance com­pen­sa­tion con­di­tions for space charge dom­i­nated beam in cERL at KEK, we in­tro­duced a new 3D cav­ity model. We first in­ves­ti­gated the in­flu­ence of the cou­plers on elec­tro­mag­netic field dis­tri­b­u­tion. As a re­sult, it was found that an asym­met­ric fo­cus­ing force is gen­er­ated by the in­flu­ence of the cou­plers. It also be­came clear that the in­flu­ence of the cou­pler kick on the op­tics sig­nif­i­cantly dev­as­tated the emit­tance com­pen­sa­tion con­di­tion from the cal­cu­lat­ing in­clud­ing space charge. Fur­ther­more, it was found that by op­ti­miz­ing the op­tics in con­sid­er­a­tion of the cou­pler kick, it is pos­si­ble to im­prove the beam con­trol ac­cu­racy and re­duce the emit­tance in beam com­mis­sion­ing.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO009  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO010 Novel Straight Merger for Energy Recovery Linacs 702
 
  • K.E. Deitrick, A. Hutton
    JLab, Newport News, Virginia, USA
  • A.C. Bartnik, C.M. Gulliford
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • S.A. Overstreet
    ODU, Norfolk, Virginia, USA
  
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
One of the most crit­i­cal de­sign con­sid­er­a­tions for an en­ergy re­cov­ery linac (ERL) is how to merge the in­jected bunch onto the linac axis with min­i­mal beam degra­da­tion. All merger de­signs in es­tab­lished and up­com­ing ma­chines in­volve sig­nif­i­cant bend­ing of the in­jected beam ’ even using a so-called straight merger bends the in­jected beam sev­eral de­grees. We pro­pose a merger which re­duces the bend­ing of the in­jected beam by an order of mag­ni­tude. By pass­ing both beams through a sep­tum mag­net fol­lowed by an rf sep­a­ra­tor cav­ity with a su­per­im­posed di­pole mag­netic field, the in­jected beam bends min­i­mally within the cav­ity, while the re­cir­cu­lated beam bends to align with the linac axis. Here we de­scribe the con­cept in de­tail and pre­sent sim­u­la­tion re­sults to demon­strate the ad­van­tages of such a de­sign, par­tic­u­larly for mag­ne­tized beams or min­i­mal en­ergy sep­a­ra­tion be­tween the in­jected and re­cir­cu­lated beams. Mea­sure­ments from an ex­per­i­ment at CBETA eval­u­at­ing the beam dy­nam­ics of the rf sep­a­ra­tor are pre­sented and com­pared with sim­u­la­tion re­sults. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO010  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO011 First Energy Recovery Operation at the S-DALINAC: RF Control Stability Measurements 706
 
  • M. Steinhorst, M. Arnold, N. Pietralla
    TU Darmstadt, Darmstadt, Germany
  • C. Burandt
    HIM, Mainz, Germany
  
  Funding: *Supported by the DFG through GRK 2128.
One of the main re­search in­stru­ments at the in­sti­tute for nu­clear physics at the TU Darm­stadt is the re­cir­cu­lat­ing su­per­con­duct­ing lin­ear ac­cel­er­a­tor S‑DALINAC. Many im­prove­ments were im­ple­mented since the first re­cir­cu­lated beam in 1991. One of the major en­hance­ment is the up­grade from a twice to a thrice re­cir­cu­lat­ing scheme in 2015/2016. With this up­grade the op­er­a­tion mode can be changed be­tween a con­ven­tional ac­cel­er­at­ing op­er­a­tion and en­ergy re­cov­ery linac (ERL) mode by an 180° rf phase­shift of the beam done via a path length vari­a­tion of the arcs in the sec­ond re­cir­cu­la­tion. ERL op­er­a­tion was not pos­si­ble when the rf con­trol sys­tem for the su­per­con­duct­ing struc­tures was set up in 2010. There­fore the cur­rent rf con­trol sys­tem is not op­ti­mized for this kind of op­er­a­tion and so it had to be tested dur­ing ERL op­er­a­tion in order to also demon­strate its ca­pa­bil­ity of this op­er­a­tion mode. In Au­gust 2017 a first once re­cir­cu­lat­ing ERL op­er­a­tion was achieved. Dur­ing this op­er­a­tion mea­sure­ments re­gard­ing the rf con­trol sta­bil­ity and the de­mand of rf power were done. This con­tri­bu­tion is dis­cussing this mea­sure­ments and pos­si­ble im­prove­ments for fu­ture en­ergy re­cov­ery beam times. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO011  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO012 Once Recirculating Energy Recovery Linac Operation of S-DALINAC* 710
 
  • M. Arnold, J. Birkhan, J. Pforr, N. Pietralla, F. Schließmann, M. Steinhorst
    TU Darmstadt, Darmstadt, Germany
  • F. Hug
    KPH, Mainz, Germany
  
  Funding: *Work supported by DFG through GRK 2128 and INST163/383-1/FUGG
Since 1991 the su­per­con­duct­ing S-DALINAC is run­ning in re­cir­cu­lat­ing op­er­a­tion. It was built in a twice re­cir­cu­lat­ing lay­out. A third re­cir­cu­la­tion beam line was added in 2015/2016 as an up­grade. The new re­cir­cu­la­tion beam line is in­stalled in-be­tween the two ex­ist­ing beam lines. It houses a path length ad­just­ment sys­tem ca­pa­ble of chang­ing the length of the orbit for re­cir­cu­la­tion by up to 10 cm cor­re­spond­ing to the RF wave length at the op­er­a­tion fre­quency of 3 GHz and con­se­quently to a free­dom of RF phase ad­just­ment by 360°. The new beam line can, thus, be uti­lized for an ac­cel­er­at­ing op­er­a­tion or, if the change in phase is set to 180°, for an en­ergy re­cov­ery linac (ERL) op­er­a­tion. In Au­gust 2017 the S-DALINAC was first op­er­ated in once re­cir­cu­lat­ing ERL mode and be­came the first run­ning ERL in Ger­many. Dif­fer­ent as­pects of this ERL run have been ob­served and were eval­u­ated. The lay­out of the S-DALINAC al­lows a once or twice re­cir­cu­lat­ing ERL mode. Beam dy­nam­ics sim­u­la­tions for both modes have been con­ducted or are cur­rently under in­ves­ti­ga­tion. This con­tri­bu­tion will dis­cuss the once re­cir­cu­lat­ing ERL op­er­a­tion, its re­sults, and fu­ture plans con­cern­ing ERL mea­sure­ments. 		 
poster icon Poster THPO012 [0.708 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO012  
About • paper received ※ 12 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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THPO016 Investigation of 2D PBG Waveguides for THz Driven Acceleration 714
SPWR007   use link to see paper's listing under its alternate paper code  
 
  • A. Vint, R. Letizia
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • R. Letizia
    Lancaster University, Lancaster, United Kingdom
  
  Funding: Work supported by the STFC PhD Studentship
Novel ac­cel­er­at­ing tech­niques that over­come the lim­i­ta­tions of con­ven­tional RF tech­nol­ogy are re­ceiv­ing sig­nif­i­cant in­ter­est. Mov­ing from RF to the THz fre­quency range, higher gra­di­ent of ac­cel­er­a­tion of high en­ergy beams can be achieved in minia­turised struc­tures. More­over, with re­spect to the op­ti­cal fre­quency range, the THz regime al­lows for larger struc­tures and bet­ter beam qual­ity to be ob­tained. In this paper, we in­ves­ti­gate the use of a 2D pho­tonic bandgap (PBG) wave­guide for THz dri­ven elec­tron ac­cel­er­a­tion. In ac­cel­er­a­tor ap­pli­ca­tions, the prop­er­ties of PBG wave­guides can be ex­ploited to damp higher order modes and offer low-loss di­elec­tric con­fine­ment at high fre­quency. In par­tic­u­lar, 2D PBG wave­guides offer a good com­pro­mise be­tween man­u­fac­tura­bil­ity, total pho­tonic bandgap con­fine­ment, and ease of par­al­lel il­lu­mi­na­tion. The struc­ture here pro­posed is op­ti­mised for max­i­mum bandgap and sin­gle mode op­er­a­tion. Dis­per­sion char­ac­ter­is­tics of the ac­cel­er­at­ing mode are stud­ied to achieve the best com­pro­mise be­tween high ac­cel­er­at­ing field and ef­fec­tive ac­cel­er­at­ing band­width, given a ~10% band­width of the THz dri­ving pulse. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO016  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO017 Progress of the Novel Three-dimensional Spiral Injection Scheme Test Experiment 717
SPWR009   use link to see paper's listing under its alternate paper code  
 
  • M.R. Rehman
    Sokendai, Ibaraki, Japan
  • K. Furukawa, H. Hisamatsu, T. Mibe, H. Nakayama, S. Ohsawa
    KEK, Ibaraki, Japan
  • H. Iinuma
    Ibaraki University, Hitachi, Ibaraki, Japan
  
  Funding: This work was supported by JSPS KAKENHI Grant Number JP26287055 and JP 23740216.
A new muon g-2/EDM ex­per­i­ment at J-PARC (E34) is under prepa­ra­tion in order to re­solve a 3𝜎 dis­crep­ancy of muon anom­alous mag­netic di­pole mo­ment be­tween the mea­sure­ment and the stan­dard model pre­dic­tion. The E34 ex­per­i­ment will em­ploy a unique three-di­men­sional spi­ral in­jec­tion scheme in order to store the muon beam into a small stor­age orbit. In order to demon­strate the fea­si­bil­ity of this novel in­jec­tion scheme, the Spi­ral In­jec­tion Test Ex­per­i­ment (SITE) with the elec­tron beam is under con­struc­tion at KEK Tsukuba cam­pus. The goals of the SITE are di­vided into two phases. In the first phase of the SITE, 80 keV DC elec­tron beam was in­jected and de­tected as a flu­o­res­cent light due to the de- ex­ci­ta­tion of the ni­tro­gen gas into so­le­noidal stor­age mag­net. In the sec­ond phase of the SITE, the pulsed elec­tron beam, and a pulsed mag­netic kicker are de­vel­oped in order to keep the pulsed beam on the very mid­plane of the so­le­noidal stor­age mag­net. This paper de­scribes the achieve­ments of the first phase of SITE and progress to­wards the sec­ond phase.
*H. Iinuma et al., Nuclear Instruments and Methos in Physics Research A, 832, 51-62 (2016). 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO017  
About • paper received ※ 12 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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THPO018 Building a 12GHz Traveling Wave Accelerating Structure Brazed Through Irises 721
 
  • V.A. Dolgashev, G.B. Bowden, M. Dal Forno, A.A. Haase
    SLAC, Menlo Park, California, USA
  • A. Grudiev
    CERN, Geneva, Switzerland
  • H. Zha
    TUB, Beijing, People’s Republic of China
  
  Ac­cel­er­at­ing struc­tures are usu­ally man­u­fac­tured by pre­ci­sion turn­ing of in­di­vid­ual cells com­bined with pre­ci­sion milling for com­plex parts such as rf power cou­plers. These mul­ti­ple parts are staked and brazed into a com­plete struc­ture. We con­sider an al­ter­na­tive ap­proach: pre­ci­sion milling of mul­ti­ple cells and cou­plers into metal blocks that com­prise halves or quad­rants of the com­plete struc­ture. We suc­cess­fully pro­duced a 12~GHz Com­pact Lin­ear Col­lider (CLIC) main linac ac­cel­er­at­ing struc­ture pro­to­type using this method. A pre­vi­ous pro­to­type was de­signed as an open struc­ture with a gap be­tween cell irises. Here we de­scribe a dif­fer­ent ap­proach, an ac­cel­er­at­ing struc­ture which is brazed through irises. It is based on a multi-cell trav­el­ing wave struc­ture de­signed at CERN for PSI, so called "T24 PSI 12 GHz". This brazed-through irises struc­ture was built at SLAC for high power tests at CERN. Here we de­scribe the de­tails of this process.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO018  
About • paper received ※ 19 September 2018       paper accepted ※ 08 October 2018       issue date ※ 18 January 2019  
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THPO020 Dynamic Behavior of Electron Beam under Rf Field and Static Magnetic Field in Cyclotron Auto-resonance Accelerator 725
 
  • Y.T. Yuan
    HUST, Wuhan, People’s Republic of China
  • K. Fan
    Huazhong University of Science and Technology, State Key Laboratory of Advanced Electromagnetic Engineering and Technology,, Hubei, People’s Republic of China
  • Y. Jiang
    Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA
  
  Funding: the National Natural Science Foundation of China
The cy­clotron auto-res­o­nance ac­cel­er­a­tor (CARA) is a novel con­cept of ac­cel­er­at­ing con­tin­u­ous gy­rat­ing charged-par­ti­cle beams to mod­er­ately or highly rel­a­tivis­tic en­er­gies, which can be used as the high power mi­crowave source and ap­plied in en­vi­ron­ment im­prove­ment area, par­tic­u­larly in the flue gas pol­lu­tion re­me­di­a­tion. In CARA, the con­tin­u­ous-wave (CW) elec­tron beam fol­lows a gy­rat­ing tra­jec­tory while un­der­go­ing the in­ter­ac­tion with the ro­tat­ing TE-mode rf field and ta­pered sta­tic mag­netic field. In the process of gy­rat­ing ac­cel­er­a­tion, the phase syn­chro­niza­tion with the rf field is au­to­mat­i­cally main­tained, so to speak, with auto-res­o­nance. Sim­u­la­tion mod­els are con­structed to study the ef­fect of rf field and sta­tic mag­netic field on elec­tron beam in CARA, where the beam en­ergy, tra­jec­tory and ve­loc­ity com­po­nent are analysed. The sim­u­la­tion re­sults match rea­son­ably well with the­o­ret­i­cal pred­i­ca­tion, which sets up a solid foun­da­tion for fu­ture de­signs of CARA. 		 
poster icon Poster THPO020 [1.448 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO020  
About • paper received ※ 11 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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THPO021 Research on X Ray Characteristics Produced by Highenergy Picosecond Electron Beam Shooting 729
 
  • X.D. Zhang, X.P. Ouyang, B. Sun, X.J. Tan, X.F. Weng
    NINT, Xi’an, People’s Republic of China
  
  Funding: Supported by National Natural Science Foundation of China(11375142)
The X ray sources based on elec­tron linac can pro­duce X-rays with high en­ergy, con­cen­trated di­rec­tions, and strong pen­e­trat­ing power, which have been widely ap­plied in var­i­ous fields. An elec­tronic lin­ear ac­cel­er­a­tor which has been built at pre­sent can pro­vide an elec­tron beam with en­ergy of 120 MeV and pulse width of pi­cosec­ond. The elec­tron beam shoot­ing at the metal tar­gets can pro­duce ul­tra-fast pulsed X-rays in the order of pi­cosec­ond. In this paper, the pulse X ray char­ac­ter­is­tics are stud­ied through sim­u­lat­ing elec­tron beam shoot­ing at four metal tar­gets with dif­fer­ent thick­ness of Au, Ta, U, W and Pb by MCNPX pro­gram. The cal­cu­la­tion shows that the X-rays can reach about 1010p/pulse and the pulse width can reach about pi­cosec­ond level, when the pulsed elec­tron beams with en­ergy of 120 MeV ,charge of 0.5nC and pulse width of pi­cosec­ond shoot­ing at Ta tar­gets. The yield and time width of pulsed X-rays are re­lated to the di­am­e­ter and thick­ness of the tar­get. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO021  
About • paper received ※ 11 September 2018       paper accepted ※ 08 October 2018       issue date ※ 18 January 2019  
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THPO022 Development Progress of the H+/H− Linear Accelerators at Tsinghua University 732
THOP06   use link to see paper's listing under its alternate paper code  
 
  • Q.Z. Xing, C.B. Bi, C. Cheng, C.T. Du, T.B. Du, X. Guan, Q.K. Guo, Y. Lei, P.F. Ma, S. Shuai, R. Tang, X.W. Wang, X.D. Xudong, H.Y. Zhang, S.X. Zheng
    TUB, Beijing, People’s Republic of China
  • W.Q. Guan, Y. He, J. Li
    NUCTECH, Beijing, People’s Republic of China
  • W.L. Liu, B.C. Wang, Z.M. Wang, Y. Yang, C. Zhao
    NINT, Shannxi, People’s Republic of China
  
  We pre­sent, in this paper, the de­vel­op­ment progress of the 13MeV pro­ton linac for the Com­pact Pulsed Hadron Source (CPHS), and the 7MeV H− linac in­jec­tor for the syn­chro­tron of the Xi’an 200MeV Pro­ton Ap­pli­ca­tion Fa­cil­ity (XiPAF).  
slides icon Slides THPO022 [4.421 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO022  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO026 The Multi-physics Analysis of Dual-beam Drift Tube Linac 735
 
  • T. He, L. Lu, W. Ma, L.P. Sun, C.C. Xing, X.B. Xu, L. Yang
    IMP/CAS, Lanzhou, People’s Republic of China
  
  The DB-DTL pro­to­type is pro­posed to val­i­date the fea-sibil­ity of multi-beam ac­cel­er­a­tor in mid­dle en­ergy re­gion. The main pa­ra­me­ters are listed in Table.1. The DB-DTL will op­er­ate as pulse in­jec­tor with the ca­pac­ity of ac­cel­er­at­ing pro­ton from 0.56 MeV to 2.5 MeV. The 35.83 kW nor­mal­ized power dis­si­pa­tion of DB-DTL dis-sipated on the cav­ity in­ter­nal sur­face will heat the cav­ity and cause cav­ity tem­per­a­ture rise and struc­tural de­for-ma­tion, which will lead to res­o­nant fre­quency shift­ing. The cool­ing water takes away the power to re­solve this prob­lem. In this paper, de­tailed multi-physics field simu-la­tion of DB-DTL is per­formed by using ANSYS multi-physics, which is a cou­pled elec­tro­mag­netic, ther­mal and struc­tural analy­sis.  
poster icon Poster THPO026 [0.759 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO026  
About • paper received ※ 11 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO028 Magnetic Field Measurement and Analysis for Drift Tube Linac of CSNS 738
 
  • B. Li, M.X. Fan, A.H. Li, P.H. Qu, Y. Wang, X.L. Wu
    CSNS, Guangdong Province, People’s Republic of China
  • Q. Chen, K.Y. Gong, W. Kang, H.C. Liupresenter, J.X. Zhou
    IHEP, Beijing, People’s Republic of China
  
  Funding: The National Natural Science Foundation of China(11105166)； Youth Innovation Promotion Association（2015011）
A 324MHz Al­varez-type Drift Tube Linac (DTL) is used to ac­cel­er­ate the H− ion beam from 3 to 80 MeV with peak cur­rent 15mA for China Spal­la­tion Neu­tron Source (CSNS). DTL is com­posed by 36 me­ters cav­ity and 161 DTs, the DT mag­net coil adopted SAKAE struc­ture with com­pact, smaller aper­ture. Mag­netic field is mea­sured by self-de­vel­oped high pre­ci­sion ro­tat­ing coil mea­sure­ment sys­tem. This paper in­tro­duces the ro­tat­ing coil mea­sure-ment sys­tem sim­ply and pre­sents the 161 DTs mag­netic field mea­sure­ment re­sults com­pre­hen­sively, in­clude mag-netic field cen­ter off­set, in­te­gral mag­netic field, higher-or­der har­mon­ics. In ad­di­tion, cool­ing test re­sult of mag­net coil is also pre­sented. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO028  
About • paper received ※ 31 August 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO029 Quality Factor and Power Loss of the CSNS DTL 741
 
  • P.H. Qu, M.X. Fan, A.H. Li, B. Li, J. Peng, Y. Wang, X.L. Wu
    CSNS, Guangdong Province, People’s Republic of China
  • Q. Chen, K.Y. Gong, H.C. Liupresenter
    IHEP, Beijing, People’s Republic of China
  
  An Al­varez-type Drift tube linac (DTL) was uti­lized to ac­cel­er­ate the H− ion beam of up to 15mA peak cur­rent from 3 to 80MeV of China Spal­la­tion neu­tron source (CSNS). For ease of man­u­fac­tur­ing and mea­sure­ment, the CSNS DTL was di­vided into four in­de­pen­dent cav­i­ties. The Q fac­tor of four cav­i­ties were given, in­clud­ing the mea­sure­ment re­sults of low-power[1] and high-power[2], and sev­eral rea­sons for the low Q fac­tor of the cav­ity in the mea­sure­ment process were analysed. Dur­ing the op-er­a­tion of the DTL, the fre­quent alarm of the water flow switch causes the power of the cav­ity to fall to 0. Esti-mate the power loss of each com­po­nent, under the cir-cum­stances of en­sur­ing ad­e­quate water flow, re­duce the alarm thresh­old of the water flow switch of some compo-nents to im­prove the sta­bil­ity of the sys­tem.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO029  
About • paper received ※ 22 August 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO030 Operation Experience of the CSNS DTL 744
 
  • H.C. Liu, Q. Chen, S. Fu, K.Y. Gong
    IHEP, Beijing, People’s Republic of China
  • M.X. Fan, A.H. Li, B. Li, J. Peng, P.H. Qu, Y. Wang, X.L. Wu
    CSNS, Guangdong Province, People’s Republic of China
  
  The China Spal­la­tion Neu­tron Source (CSNS) Drift tube linac (DTL) ac­cel­er­ates H− beam from 3 to 80MeV with 4 in­de­pen­dent tanks. The 80MeV beam ac­cel­er­a­tion was achieved in Jan­u­ary 2018. The linac is a key to the re­li­a­bil­ity of the whole CSNS fa­cil­ity since all the beams stop when these up­stream fa­cil­i­ties fail. Many ef­forts have been made for DTL re­li­able op­er­a­tion. This paper pre­sents the op­er­a­tion ex­pe­ri­ence learned in DTL com-mis­sion­ing.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO030  
About • paper received ※ 28 August 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO031 RF Conditioning and Beam Commissioning Status of CSNS DTL 747
 
  • Y. Wang, M.X. Fan, A.H. Li, B. Li, J. Peng, P.H. Qu, X.L. Wu
    CSNS, Guangdong Province, People’s Republic of China
  • Q. Chen, K.Y. Gong, H.C. Liupresenter
    IHEP, Beijing, People’s Republic of China
  
  The high power RF con­di­tion­ing of CSNS DTL was fin­ished in April 2017 with peak input power 1.6MW, 650us pulse width, 25Hz rep­e­ti­tion fre­quency. With care­ful tun­ing of RF am­pli­tude and phase, beam was ac­cel­er­ated to 80MeV suc­cess­fully with max­i­mum peak beam cur­rent 12mA and about 98% trans­mis­sion ef­fi­ciency. DTL op­er­ate sta­bly at full power level with sev­eral trips per day with­out beam in­ter­rup­tion after six months com­mis­sion­ing. The whole RF con­di­tion­ing process was pre­sented and some de­tails of beam com­mis­sion­ing were de­scribed in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO031  
About • paper received ※ 05 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO032 CSNS Linac Beam Commissioning Tools and Experience 750
 
  • Y. Li, Z.P. Li, S. Wang
    IHEP, Beijing, People’s Republic of China
  • J. Pengpresenter
    CSNS, Guangdong Province, People’s Republic of China
  
  The China Spal­la­tion Neu­tron Source (CSNS) suc­cess­fully ac­cel­er­ated the H− beam to 80 MeV in Jan­u­ary 2018, mark­ing a key progress in the beam com­mis­sion­ing. One of the keys to suc­cess is the de­vel­op­ment and use of soft­ware tools. XAL, a Java-based soft­ware in­fra­struc­ture orig­i­nally de­vel­oped by SNS was ap­plied for CSNS beam com­mis­sion­ing. We have de­vel­oped and trans­planted many ap­pli­ca­tions based on XAL. Some of the ap­pli­ca­tions for the Linac are de­scribed ,and some ex­pe­ri­ences are shared.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO032  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO033 The Development of Permanent Magnet Quadrupoles for Xipaf DTL 753
 
  • B.C. Wang, M.T. Qiu, Z.M. Wang, C.Y. Wei
    NINT, Shannxi, People’s Republic of China
  • C.T. Du, Q.K. Guo, X.W. Wang, Q.Z. Xing, S.X. Zheng
    TUB, Beijing, People’s Republic of China
  
  Per­ma­nent mag­net quadrupoles (PMQs) are de­vel­oped for the DTL of Xi’an 200 MeV Pro­ton Ap­pli­ca­tion Fa­cil­ity (XiPAF). In this paper, we de­scribe the fab­ri­ca­tion and mea­sure­ments for the Hal­bach-type PMQs. The main pro­ce­dure of the PMQ man­u­fac­ture is pre­sented. And the mag­netic mea­sure­ments of PMQs are car­ried out with the help of vi­brat­ing wire, Hall probe and ro­tat­ing coil re­spec­tively. The re­sults show the PMQs are able to meet the re­quire­ments of XiPAF DTL.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO033  
About • paper received ※ 10 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO034 Experimental Study of Tuning Method on a Model Alvarez DTL Cavity for CPHS Project 756
 
  • Y. Lei, X. Guan, R. Tang, X.W. Wang, Q.Z. Xing, S.X. Zheng
    TUB, Beijing, People’s Republic of China
  
  This ar­ti­cle is de­voted to the ex­per­i­men­tal study of tun-ing method for an Al­varez-type drift tube linac (DTL) of the Com­pact Pulse Hadron Source (CPHS) pro­ject at Ts­inghua Uni­ver­sity. The biperi­odic struc­ture based on the post cou­plers are in­tro­duced to over­come the in­sta­bil­ity of the Al­varez DTL tank which is used to op­er­ate in 0 (or 2π) mode. The ex­per­i­men­tal method and re­sults are pre-sented, and the tun­ing scheme for the for­mal CPHS DTL is sum­ma­rized from the tun­ing ex­per­i­ment.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO034  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO035 Tuning and Low Power Test of the 325 MHz IH-DTL at Tsinghua University 759
 
  • R. Tang, C.T. Du, X. Guan, Y. Lei, P.F. Ma, K.D. Man, C.-X. Tang, X.W. Wang, Q.Z. Xing, W.B. Ye, H.Y. Zhang, S.X. Zheng
    TUB, Beijing, People’s Republic of China
  • J. Li
    NUCTECH, Beijing, People’s Republic of China
  
  An in­ter­dig­i­tal H-mode drift tube linac (IH-DTL), which ac­cel­er­ates pro­ton beam from 3 MeV to 7 MeV has been de­signed and as­sem­bled at Ts­inghua Uni­ver­sity. There are 8 plungers in the 1 m tank and one co-ax­ial cou­pler is used to feed the power. The fre­quency is tuned to 325 MHz. The field dis­tri­b­u­tion is mea­sured by the bead per­tur­ba­tion method. Fi­nally, the gap volt­age error has been tuned to be smaller than ±3.0%, which sat­is­fies the de­sign re­quire­ment. The Q fac­tor of the tank is 7000 while the power dis­si­pa­tion is 244 kW. De­tails of the low power test is pre­sented.  
poster icon Poster THPO035 [1.268 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO035  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO036 Error Study of CPHS DTL after Assembly 763
SPWR014   use link to see paper's listing under its alternate paper code  
 
  • P.F. Ma, C.T. Du, X. Guan, Q.K. Guo, Y. Lei, R. Tang, X.W. Wang, Q.Z. Xing, S.X. Zheng
    TUB, Beijing, People’s Republic of China
  • B.C. Wang
    NINT, Shannxi, People’s Republic of China
  
  The Com­pact Pulsed Hadron Source (CPHS) at Ts­inghua Uni­ver­sity is one multi-pur­pose pulsed neu­tron source. The in­jec­tor of the CPHS is a linac, which mainly con­sists of a source, a low-en­ergy beam trans­port line (LEBT), a radio fre­quency quadru­pole (RFQ) and a drift tube linac (DTL). The error study of the DTL for CPHS is pre­sented in this paper. The error study can pro­vide the field tol­er­ances in the DTL cav­ity and the align­ment tol­er­ance be­tween the RFQ and DTL.  
poster icon Poster THPO036 [2.645 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO036  
About • paper received ※ 06 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO038 Status of the Power Couplers for the CSNS DTL 767
 
  • M.X. Fan, A.H. Li, B. Li, P.H. Qu, Y. Wang, X.L. Wu
    CSNS, Guangdong Province, People’s Republic of China
  • Q. Chen, K.Y. Gong, H.C. Liu
    IHEP, Beijing, People’s Republic of China
  
  There are four Drift Tube Linac (DTL) tanks in China Spal­la­tion Neu­tron Source (CSNS) Pro­ject. Each DTL tank re­quires a power cou­pler with a peak power of 2 MW and a duty cycle of 1.5% for beam op­er­a­tion. After ap­prox­i­mately two years ma­chin­ing, all four cou­plers were al­ready in­stalled in the tun­nel be­fore year 2017. Up to now, the first phase of beam tun­ing has been com­pleted, the max­i­mum trans­mis­sion power of the cou­pler ex­ceeds 1.7 MW with a pulse width of 650 μs and a rep­e­ti­tion rate of 25 Hz, mean­while, the vac­uum is main­tained on the order of 10-6 Pa dur­ing the op­er­a­tion and no break­down was ob­served. This paper de­scribes the ar­chi­tec­ture, the fab­ri­ca­tion, the low power test re­sults and the high power con­di­tion­ing process of the cou­pler. Some prob­lems en­coun­tered are also pre­sented.
This work was supported by Youth Innovation Promotion Association of CAS (2015011) 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO038  
About • paper received ※ 30 August 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO039 The Status of CSNS Front End 771
 
  • H. Li, X. Cao, W. Chen, T. Huang, S. Liu, K. Xue
    CSNS, Guangdong Province, People’s Republic of China
  • S. Fu, Y.J. Lv, H.F. Ouyang, Y.C. Xiaopresenter
    IHEP, Beijing, People’s Republic of China
  
  CSNS front end is cur­rently under run­ning, which con­sists of a H− pen­ning ion source(IS), a low en­ergy beam trans­port(LEBT), a radio fre­quency quadru­pole (RFQ) and a medium en­ergy beam trans­port(MEBT). CSNS ion source is a type of Pen­ning sur­face plasma source, sim­i­lar to ISIS ion source. Ce­sium is used to en­hance the H− ion pro­duc­tion ef­fi­ciency. The ion source is run­ning with duty fac­tor of 1.25%(25Hz and 500us). Nor­mally, 40mA H− beam from ion source with 50keV can be de­liv­ered into LEBT. Three so­le­noids and two di­rec­tion mag­nets are em­ployed to trans­port and match the beam from the ion source into the RFQ. The pre-chop­per is in­stalled at the end of LEBT. The chop­per mainly works at 3.8-4.2 kV and 1 MHz rate, which is about the RF fre­quency of the ring at in­jec­tion. The rise time is less than 10ns，which ful­fills the re­quire­ment of ring in­jec­tion. For the RFQ, it is a 324MHz 4-vane type with a out­put en­ergy of 3.0MeV and the length of 3.62m. The input cav­ity power is about 400kW. Dur­ing com­mis­sion­ing, 16mA H− beam can be ob­tained at the exit of RFQ, and the RFQ trans­mis­sion rate is up to 94%.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO039  
About • paper received ※ 03 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO040 Operation Experiences of the J-PARC Linac 774
 
  • K. Hasegawa
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  
  The J-PARC linac has de­liv­ered beam to users since 2008. As of 2018, the linac pro­vides a 40 mA beam at an en­ergy of 400 MeV to the fol­low­ing Rapid Cy­cling Syn­chro­tron. We have had many is­sues to im­pede high avail­abil­ity dur­ing the op­er­a­tion. One of them was trou­bles of high volt­age power sup­ply of kly­strons. The other cat­e­gory is re­lated to vac­uum prop­erty in ac­cel­er­at­ing cav­i­ties. The vac­uum pumps were re­in­forced at the RFQ#1 in 2009. The clean­ing of the in­side sur­face of some ac­cel­er­a­tion cav­i­ties were per­formed after the big earth­quake in 2011. The cool­ing water flow rate drop had been a long-time issue. We mod­i­fied a cool­ing sys­tem to take bet­ter flow bal­ances. As a re­sult of these im­prove­ment, the avail­abil­ity is ap­prox­i­mately 92% or more in these days. How­ever, we have en­coun­tered an­other issue due to some aging com­po­nents. The op­er­a­tion ex­pe­ri­ences and avail­abil­ity im­prove­ment at the J-PARC linac will be pre­sented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO040  
About • paper received ※ 19 September 2018       paper accepted ※ 08 October 2018       issue date ※ 18 January 2019  
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THPO042 An Optimization Method of the Nose-cone Buncher Cavity 778
 
  • W.L. Liu, P.T. Cong, Z.M. Wang
    NINT, Shannxi, People’s Republic of China
  • H. Jiang, S.X. Zheng
    TUB, Beijing, People’s Republic of China
  
  The nose-cone buncher cav­ity is widely used on pro­ton ac­cel­er­a­tors. It’s im­por­tant to prop­erly op­ti­mize the cav­ity geom­e­try for fine RF per­for­mance. Howev-er, cur­rently the op­ti­miza­tion is usu­ally car­ried out man­u­ally and the cri­te­ria are not ob­jec­tive enough. In this paper, an op­ti­miza­tion method using the multi-ob­jec­tive, multi-vari­able op­ti­miza­tion ap­proach is pre­sented. The geom­e­try and RF pa­ra­me­ters are con-sidered as the vari­ables and ob­jec­tives re­spec­tively. The goal func­tion is de­fined as the weighted sum of mul­ti­ple RF pa­ra­me­ters. The multi-vari­able func­tions are ap­prox­i­mately de­rived from the sin­gle-vari­able func­tions based on elec­tro­mag­netic sim­u­la­tion. And an op­ti­miza­tion code is de­vel­oped ac­cord­ingly which has been ap­plied to the XiPAF de­buncher op­ti­miza­tion.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO042  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO043 ESS Normal Conducting Linac Status and Plans 781
 
  • E. Sargsyan, H. Danared, F. Hellström, G. Hulla, Ø. Midttun, J.S. Schmidt
    ESS, Lund, Sweden
  • I. Bustinduy, N. Garmendia, J.L. Muñoz
    ESS Bilbao, Zamudio, Spain
  • L. Celona, S. Gammino, L. Neri
    INFN/LNS, Catania, Italy
  • A.C. Chauveau, B. Pottin
    CEA/IRFU, Gif-sur-Yvette, France
  • F. Grespanpresenter, A. Pisent
    INFN/LNL, Legnaro (PD), Italy
  • P. Mereu
    INFN-Torino, Torino, Italy
  
  The Eu­ro­pean Spal­la­tion Source (ESS) uses a lin­ear ac­cel­er­a­tor to de­liver the high in­ten­sity pro­ton beam to the tar­get sta­tion for pro­duc­ing in­tense beams of neu­trons. The av­er­age beam power is 5 MW with a peak beam power at the tar­get of 125 MW. The nor­mal con­duct­ing lin­ear ac­cel­er­a­tor (linac) op­er­at­ing at 352.21 MHz ac­cel­er­ates a pro­ton beam of 62.5 mA from 0.075 to 90 MeV. It con­sists of an ion source, Low En­ergy Beam Trans­port (LEBT), Radio Fre­quency Quadru­pole (RFQ), Medium En­ergy Beam Trans­port (MEBT), and Drift Tube Linac (DTL). The de­sign, con­struc­tion and test­ing of those struc­tures is done by Eu­ro­pean part­ner labs as an in-kind con­tri­bu­tion to the ESS pro­ject. This paper pre­sents the sta­tus and plans for the ESS nor­mal con­duct­ing linac.
E.Sargsyan for the ESS NC Linac collaboration team 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO043  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO045 Tuning Esperience on the ESS DTL Cold Model 784
 
  • F. Grespan, A. Baldo, P. Bottin, G.S. Mauro, A. Palmieri, A. Pisent
    INFN/LNL, Legnaro (PD), Italy
  • P. Mereu, M. Mezzano
    INFN-Torino, Torino, Italy
  
  An alu­minum model of the ESS DTL tank 2 has been de­liv­ered to INFN-LNL in de­cem­ber 2017. The tank is 7.1 m long, equipped with mov­able tuners and mov­able post cou­plers. The pur­pose of this DTL model is to ver­ify the RF de­sign choices (in par­tic­u­lar on the first 2 tanks where the Post cou­pler dis­tri­b­u­tion is ir­reg­u­lar) as well as im­ple­ment and debug al­go­rithms and pro­ce­dure for sta­bi­liza­tion and tun­ing. The prepara­tory sim­u­la­tion work and the re­sults of mea­sure­ments cam­paign are here pre­sented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO045  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO046 Status of the FAIR Proton Linac 787
 
  • C.M. Kleffner, S. Appel, R. Berezov, J. Fils, P. Forck, M. Kaiser, K. Knie, C. Mühle, S. Puetz, A. Schnase, G. Schreiber, A. Seibel, T. Sieber, V. Srinivasan, J. Trüller, W. Vinzenz, C. Will
    GSI, Darmstadt, Germany
  • A. Almomani, H. Hähnel, U. Ratzinger, M. Schuett, M. Syha
    IAP, Frankfurt am Main, Germany
  
  As part of the ac­cel­er­a­tor chain for an­tipro­ton pro­duc­tion of the FAIR fa­cil­ity, a spe­cial high-in­ten­sity short pulsed 325 MHz pro­ton linac is being de­vel­oped. The Pro­ton linac is de­signed to de­liver a beam cur­rent of 70 mA with an en­ergy of 68 MeV. A 2.45 GHz ECR source de­signed for the gen­er­a­tion of 100 mA beams with an en­ergy of 95 keV is cur­rently being tested at CEA/Saclay. The pro­duc­tion of the struc­ture of the IAP lad­der RFQ is nearly com­pleted. First parts of the RFQ vac­uum cham­bers have been suc­cess­fully cop­per­plated at the GSI. Seven Thales Kly­strons have been de­liv­ered to GSI at the be­gin­ning of 2018 and are nearly ready for use. The com­ple­tion of the setup of the HV mod­u­la­tor is ex­pected end of the year 2018. The state of pro­cure­ment and de­vel­op­ment of fur­ther ac­cel­er­a­tor com­po­nents will be pre­sented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO046  
About • paper received ※ 12 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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THPO047 SPIRAL2 Injector Commissioning 790
THOP01   use link to see paper's listing under its alternate paper code  
 
  • R. Ferdinand, M. Di Giacomo, H. Franberg, O. Kamalou, J.-M. Lagniel, G. Normand, A. Savalle, F. Varenne
    GANIL, Caen, France
  • D. Uriot
    CEA/DRF/IRFU, Gif-sur-Yvette, France
  
  The SPI­RAL2 in­jec­tor is com­posed of two ion sources (p/d and heavy ions up to A/Q=3) fol­lowed by a 730 keV/u RFQ. Beam com­mis­sion­ing has started in 2014 in par­al­lel with the su­per­con­duct­ing linac and HEBT in­stal­la­tions. The RFQ beam com­mis­sion­ing started soon after the first RF con­di­tion­ing done in Oc­to­ber 2015. This paper de­scribes the RFQ beam mea­sure­ments done on the di­ag­nos­tic plate for the ref­er­ence par­ti­cles (H+, 4He2+ and re­cently 18O6+) and the dif­fi­cul­ties en­coun­tered for the RFQ com­mis­sion­ing at the A/Q=3 field level.  
slides icon Slides THPO047 [7.846 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO047  
About • paper received ※ 11 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO048 Low Power Measurement of a 1300-MHz RFQ Cold Model 794
THOP02   use link to see paper's listing under its alternate paper code  
 
  • Y. Kondo, T. Morishita, J. Tamura
    JAEA/J-PARC, Tokai-mura, Japan
  • M. Otani
    KEK, Ibaraki, Japan
  
  Funding: This work is supported by JSPS KAKENHI Grant Number 17K18784.
A muon linac de­vel­op­ment for a new muon g-2/EDM ex­per­i­ment is now going on at J-PARC. Muons from the muon beam line (H-line) of the J-PARC muon fa­cil­ity are once stopped in a sil­ica aero­jel tar­get and room tem­per­a­ture muo­ni­ums are evap­o­rated from the aero­gel. They are dis­so­ci­ated with the lasers to be the ultra slow muons, then ac­cel­er­ated up to 212 MeV using a lin­ear ac­cel­er­a­tor. The low en­ergy part of this muon linac con­sists of a 324-MHz RFQ and an IH DTL. The fre­quency is in­creased to 1296 MHz at the fol­low­ing CCL sec­tion. We pro­pose to re­place the low en­ergy sec­tion to a 1300-MHz RFQ to sim­plify the con­fig­u­ra­tion of the muon linac. The 1300-MHz RFQ will be ex­tremely small com­pared to con­ven­tional RFQs, there­fore we made a cold model to proof the fea­si­bil­ity of this scheme. In this paper, the re­sult of low-power mea­sure­ment of the 1300-MHz RFQ cold model is de­scribed. 		 
slides icon Slides THPO048 [2.160 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO048  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO049 Field Tuning of a Radio-frequency Quadrupole Using Full 3D Modeling 798
 
  • T. Morishita, K. Hasegawa, Y. Kondo, H. Oguri
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  • M. Otani
    KEK, Ibaraki, Japan
  
  The ra­dio-fre­quency quadru­pole linac (RFQ) is op­er­at­ing in the fron­tend of the J-PARC linac to ac­cel­er­ates 50 mA neg­a­tive hy­dro­gen beams from 0.05 MeV to 3 MeV. As a backup, the spare RFQ has been fab­ri­cated in 2018. The vane-volt­age ramp­ing is adopted to im­prove the ac­cel­er­a­tion ef­fi­ciency so that the cross-sec­tional shape is ad­justed lon­gi­tu­di­nally to pro­duce the de­signed volt­age dis­tri­b­u­tion. Then, the three-di­men­sional cav­ity mod­els in­clud­ing mod­u­la­tions and cut­backs were cre­ated in CST Mi­cro-Wave Stu­dio. The vane-base widths and cut­back depths were op­ti­mized to pro­duce the de­sired vane-volt­age dis­tri­b­u­tion. In the final tun­ing, the heights of the stub turn­ers were also de­ter­mined based on the tuner re­sponses ob­tained from the full 3D mod­els. In this paper, the de­tailed de­sign process of the cav­ity di­men­sions and the re­sult of the low-power mea­sure­ments are de­scribed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO049  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO050 Research on the New Cavity Structure of RFQ Accelerator With Bent Vanes at IMP 802
THOP03   use link to see paper's listing under its alternate paper code  
 
  • L. Yang, T. He, Y. He, C.X. Li, L. Lu, L.P. Sun, C.C. Xing
    IMP/CAS, Lanzhou, People’s Republic of China
  • L. Yang
    University of Chinese Academy of Sciences, Beijing, People’s Republic of China
  
  A new cav­ity struc­ture of RFQ ac­cel­er­a­tor with bent vanes is pro­posed to meet the minia­tur­iza­tion re­quire­ment of low fre­quency heavy ion ac­cel­er­a­tors at In­sti­tute of Mod­ern Physics (IMP), Chi­nese Acad­emy of Sci­ences. The new struc­ture has a down­sized cross sec­tion by bend­ing vanes while keep­ing a cer­tain vane lengths. It also pos­sesses the ad­van­tages of sim­ple cool­ing struc­ture and high power ef­fi­cient when used in low fre­quency. The new struc­ture has ob­vi­ous ad­van­tages in re­duc­ing man­u­fac­tur­ing dif­fi­culty of cav­ity, cut­ting down pro­ject cost, en­hanc­ing fa­cil­ity re­li­a­bil­ity and sta­bil­ity.  
slides icon Slides THPO050 [1.407 MB]  
poster icon Poster THPO050 [0.398 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO050  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO051 The Multi-physics Analysis of LEAF RFQ 805
 
  • X.B. Xu, T. He, Y. He, C.X. Li, L. Lu, W. Ma, A. Shi, L.B. Shi, L.P. Sun, C.C. Xing, L. Yang, H.W. Zhao
    IMP/CAS, Lanzhou, People’s Republic of China
  
  The 81.25 MHz CW RFQ is de­signed to ac­cel­er­ate heavy ions with Q/A from 1/7 to 1/2 at 0.5 MeV/u for the Low En­ergy Ac­cel­er­a­tor Fa­cil­ity (LEAF) at the In­sti­tute of Mod­ern Physics (IMP) of the Chi­nese Acad­emy of Sci­ence (CAS). The four-vane RFQ con­sists of six mod-ules with a total length of 5.95 me­ters, For the CW oper-at­ing mode, ther­mal man­age­ment will be a very im­por­tant issue, There­fore a multi-physics analy­sis is nec­es­sary to en­sure that the cav­ity can sta­bly op­er­ate at the high RF power . The multi-physics analy­sis process in­cludes RF elec­tro­mag­netic analy­sis, ther­mal analy­sis, me­chan­i­cal analy­sis, and the fre­quency shift, the cool­ing water sys­tem is used for fre­quency tun­ning by the tem­per­a­ture ad­just­ment, and also an­a­lyze RFQ un­der­cuts, fixed tuners, and pi-mode rods, the re­sults show that the ther­mal and struc­tural de­sign of this RFQ is rea­son­able.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO051  
About • paper received ※ 17 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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THPO052 High Power Test of the LEAF-RFQ 808
 
  • L. Lu, Y. He, W. Ma, L.B. Shi, L.T. Sun, L.P. Sun, L. Yang, Y. Yang, H.W. Zhao
    IMP/CAS, Lanzhou, People’s Republic of China
  
  High power heavy ion dri­vers re­quire a CW low-fre­quency ac­cel­er­a­tor for ini­tial ac­cel­er­a­tion. A CW four-vane radio fre­quency quadru­pole (RFQ) ac­cel­er­a­tor is de­signed to ac­cel­er­ate heavy ions A/q up to 7 from 14 keV/u to 500 keV/u, as a new in­jec­tor for the Low En­ergy Ac­cel­er­a­tor Fa­cil­ity (LEAF) at In­sti­tute of Mod­ern Physics (IMP). The mea­sure­ments of low power test were re­ported pre­vi­ously. In this paper, the re­sults of high power test of the RFQ, in­clud­ing the test of the ac­cel­er­a­tion sys­tems and beam pro­files, will be pre­sented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO052  
About • paper received ※ 07 September 2018       paper accepted ※ 08 October 2018       issue date ※ 18 January 2019  
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THPO053 Status of the China Material Irradiation Facility RFQ 811
 
  • C.X. Li, W.L. Chen, W.P. Dou, Z. Gao, Y. He, G. Huang, C.L. Li, L. Lu, W. Ma, A. Shi, L.B. Shi, L.P. Sun, F.F. Wang, W.B. Wang, Z.J. Wang, Q. Wu, X.B. Xu, L. Yang, P.Y. Yu, B. Zhang, J.H. Zhang, P. Zhang, T.M. Zhu
    IMP/CAS, Lanzhou, People’s Republic of China
  
  Funding: Supported by the National Magnetic Confinement Fusion Science Program of China (Grant No.2014GB104001) and the National Natural Science Foundation of China (Grant No.91426303).
The pulsed high power test and beam test of the China Ma­te­r­ial Ir­ra­di­a­tion Fa­cil­ity RFQ have been im­ple­mented. Be­fore this, the radio fre­quency mea­sure­ments and tun­ing are per­formed. In this paper, the processes and re­sults of the radio fre­quency mea­sure­ments, tun­ing, pulsed high power test and beam test will be pre­sented. The re­sults of tests are in good agree­ment with the de­sign. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO053  
About • paper received ※ 12 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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THPO054 Recent Progress of a CW 4-rod RFQ for the SSC-LINAC 814
 
  • Z.S. Li, Y. Cong, H. Du, Y. He, L. Jing, Q.Y. Kong, X.N. Li, J. Meng, G.D. Shen, K.D. Wang, Z.J. Wang, W. Wei, J.X. Wu, J.W. Xia, H.M. Xie, W.J. Xie, Z. Xu, J.C. Yang, Y.Q. Yang, X. Yin, Y.J. Yuan, Y. Zhang
    IMP/CAS, Lanzhou, People’s Republic of China
  • Y.R. Lu
    PKU, Beijing, People’s Republic of China
  
  The SSC-LINAC is under de­sign and con­struc­tion as a lin­ear in­jec­tor for the Sep­a­rated-Sec­tor Cy­clotron (SSC) of the Heavy Ion Re­search Fa­cil­ity at Lanzhou (HIRFL). The con­tin­u­ous-wave (CW) 4-rod ra­dio-fre­quency quad-ru­pole (RFQ) of the SSC-LINAC has im­por­tant progress in past years. In the au­tumn of 2016, the cav­ity has been op­er­ated with 35 kW on CW mode in au­to­matic RF con-trolled mode dur­ing RF power com­mis­sion­ing, which is needed to ac­cel­er­ate 238U34+ beams. The beam trans­mis-sion ef­fi­ciency, trans­verse emit­tance and en­ergy spread has been ob­tained in beam com­mis­sion­ing. In this paper, the re­sults of ex­per­i­ments will be pre­sented and dis­cussed in de­tail.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO054  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO057 Redesign of CERN Linac3 RFQ for Lead 29+ 818
 
  • S. Benedetti, G. Bellodi, J.-B. Lallement, A.M. Lombardi
    CERN, Geneva, Switzerland
  
  CERN Linac3 is at the start of the CERN Heavy Ion Fa­cil­ity, pro­vid­ing 4.2 MeV/u ion beams to the Low En­ergy Ion Ring (LEIR). It mostly ac­cel­er­ates 208Pb29+, though in re­cent years runs were per­formed with 40Ar11+ and 129Xe22+, in view of the in­creas­ing in­ter­est of the physics com­mu­nity to­wards lighter ions ex­per­i­ments. In the frame­work of the LHC In­jec­tors Up­grade (LIU) pro­ject, mea­sure­ments and beam dy­nam­ics sim­u­la­tions showed that a trans­mis­sion bot­tle­neck of Linac3 is rep­re­sented by the RFQ. As this ac­cel­er­a­tor was orig­i­nally de­signed for 208Pb25+, the lower beam rigid­ity of the heavy ions cur­rently in use and planned for the fu­ture per­mits a re­design of the RFQ op­tics aimed at in­creas­ing its trans­verse ac­cep­tance, and thus the trans­mit­ted beam cur­rent. A study of this has been per­formed, and the method­ol­ogy adopted and the re­sults are pre­sented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO057  
About • paper received ※ 11 September 2018       paper accepted ※ 08 October 2018       issue date ※ 18 January 2019  
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THPO058 RF Design of a High-frequency RFQ Linac for PIXE Analysis 822
SPWR016   use link to see paper's listing under its alternate paper code  
THOP04   use link to see paper's listing under its alternate paper code  
 
  • H.W. Pommerenke, A. Bilton, A. Grudiev, A.M. Lombardi, S.J. Mathot, E. Montesinos, M.A. Timmins, M. Vretenar
    CERN, Geneva, Switzerland
  • H.W. Pommerenke, U. van Rienen
    Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
  
  Funding: This work has been sponsored by the Wolfgang Gentner Program of the German Federal Ministry of Education and Research (grant no. 05E12CHA).
Pro­tons with an en­ergy of few MeV are com­monly used for Ion Beam Analy­sis of ma­te­ri­als, in par­tic­u­lar with the Pro­ton In­duced X-ray Emis­sion tech­nique (PIXE). Be­cause of its non-dam­ag­ing char­ac­ter, PIXE is used in a va­ri­ety of fields, in par­tic­u­lar for the di­ag­no­sis of cul­tural her­itage art­work. A com­pact ac­cel­er­a­tor based on a high fre­quency RFQ (Radio Fre­quency Quadru­pole) linac has been de­signed and is being built at CERN. The length of the RFQ is only one meter and it al­lows the ac­cel­er­a­tion of a pro­ton beam up to an en­ergy of 2 MeV. The com­plete sys­tem is con­ceived to be trans­portable, al­low­ing PIXE analy­sis al­most any­where. This paper cov­ers the RF de­sign of the com­pact RFQ op­er­at­ing at 750 MHz. We pre­sent gen­eral ac­cel­er­a­tor pa­ra­me­ters and the cur­rent state of the RF de­sign, which in­cludes RFQ geom­e­try and cou­pler de­sign, ther­mal sim­u­la­tion and first par­ti­cle track­ing re­sults. 		 
slides icon Slides THPO058 [2.404 MB]  
poster icon Poster THPO058 [2.192 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO058  
About • paper received ※ 11 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO060 First RF Measurements of the 325 MHz Ladder RFQ 826
 
  • M. Schuett, U. Ratzinger, M. Syha
    IAP, Frankfurt am Main, Germany
  
  Funding: BMBF 05P15RFRBA
Based on the pos­i­tive re­sults of the un­mod­u­lated 325 MHz Lad­der-RFQ pro­to­type from 2013 to 2016, we de­vel­oped and de­signed a mod­u­lated 3.3 m Lad­der-RFQ*. The un­mod­u­lated pro­to­type Lad­der-RFQ fea­tures a very con­stant volt­age along the axis. The RFQ was high power tested at the GSI test stand. It ac­cepted 3 times the RF power level needed in op­er­a­tion**. That level cor­re­sponds to a Kil­patrick fac­tor of 3.1 with a pulse length of 200 µs. The 325 MHz RFQ is de­signed to ac­cel­er­ate pro­tons from 95 keV to 3.0 MeV ac­cord­ing to the de­sign pa­ra­me­ters of the pro­ton linac within the FAIR pro­ject. This par­tic­u­lar high fre­quency cre­ates dif­fi­cul­ties for a 4-ROD type RFQ, which trig­gered the de­vel­op­ment of a Lad­der RFQ with its higher sym­me­try. The re­sults of the un­mod­u­lated pro­to­type have shown, that the Lad­der-RFQ is a suit­able can­di­date for that fre­quency. For the pre­sent de­sign duty cy­cles are fea­si­ble up to 5%. The basic de­sign and ten­der­ing of the RFQ has been suc­cess­fully com­pleted in 2016. Man­u­fac­tur­ing will be com­pleted in Au­gust 2018. We will show the the fi­nal­iza­tion of man­u­fac­tur­ing as well as first low level RF mea­sure­ments of the Lad­der RFQ.
*Journal of Physics: Conf. Series 874 (2017) 012048
**Proceedings of LINAC2016, East Lansing, TUPLR053 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO060  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO061 Beam Characterization of the MYRRHA-RFQ 830
SPWR017   use link to see paper's listing under its alternate paper code  
 
  • P.P. Schneider, M. Droba, O. Meusel, H. Podlech, A. Schempp
    IAP, Frankfurt am Main, Germany
  • D. Noll
    CERN, Geneva, Switzerland
  
  Funding: This work is supported by the German Federal Ministry of Education and Research (BMBF) #05P15RFRBA and HORIZON 2020 for the MYRRHA project #662186 and HIC for FAIR.
The Lin­ear Ac­cel­er­a­tor for the MYRRHA pro­ject* is under con­struc­tion. In a first step the linac up to 100 MeV will be re­al­ized. The LEBT sec­tion has been set into op­er­a­tion in Bel­gium and the RFQ is in­stalled in sum­mer 2018. A sys­tem to an­a­lyze the ion beam con­sist­ing of a slit-grid emit­tance scan­ner, a beam dump and a mo­men­tum spec­trom­e­ter, called di­ag­nos­tic train de­scripted in **, will be set on the rails to char­ac­ter­ize the beam at the RFQ in­jec­tion point. The re­sults will be used to ad­just the op­ti­mal match­ing for the RFQ. After the mea­sure­ments down­stream the LEBT, the di­ag­nos­tic train be­gins its jour­ney along the beam line and at the first sta­tion the RFQ is in­stalled. The ac­cel­er­ated beam of the RFQ is then an­a­lyzed and op­ti­mized. In ad­di­tion to op­ti­miza­tion of trans­mis­sion the ar­ti­fi­cial pro­duc­tion of beam off­sets in the LEBT is of spe­cial in­ter­est. These will be mea­sured at the in­jec­tion point to es­ti­mate the range of pos­si­ble off­sets. In the fol­low­ing mea­sure­ments these off­sets will be used to study the in­flu­ence of the off­sets on the RFQ per­for­mance. Fur­ther­more, the RFQ pa­ra­me­ters are var­ied to see their in­flu­ence on the beam trans­port, trans­mis­sion and beam qual­ity.
* H.Aı̈t Abderrahim et al. "MYRRHA: A multipurpose accelerator driven system for research & development", 2001
** 1st Experiments at the CW-Operated RFQ for Intense Proton Beams, LINAC16 		 
poster icon Poster THPO061 [4.610 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO061  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO062 IFMIF/EVEDA RFQ Preliminary Beam Characterization 834
 
  • E. Fagotti, L. Antoniazzi, L. Bellan, M. Comunian, F. Grespanpresenter, M. Montis, A. Palmieri, A. Pisent, F. Scantamburlo
    INFN/LNL, Legnaro (PD), Italy
  • T. Akagi, K. Kondo, K. Sakamoto, T. Shinya, M. Sugimoto
    QST, Aomori, Japan
  • P. Cara
    IFMIF/EVEDA, Rokkasho, Japan
  • H. Dzitko, I.M. Moya
    F4E, Germany
  • R. Heidinger, A. Marqueta
    Fusion for Energy, Garching, Germany
  • I. Podadera
    CIEMAT, Madrid, Spain
  
  The IFMIF/EVEDA RFQ is the longest and pow­er­ful op­er­ated. There­fore, it re­quires a care­ful char­ac­ter­i­za­tion from sev­eral as­pects: beam dy­nam­ics, RF, me­chan­ics, in­stal­la­tion and com­mis­sion­ing. Due to the very large power han­dling, the pre­lim­i­nary beam op­er­a­tion was de­cided to be per­formed with a low pro­ton beam cur­rent at one half of the volt­age needed for deuteron ac­cel­era-tion, i.e. from 8 mA to 30 mA at 2.5 MeV in pulsed mode, with re­spect to the nom­i­nal 130-mA deuteron beam at 5 MeV in CW. In this frame­work, it will be pre­sented the char­ac­ter­i­za­tion of the RFQ in terms of sim­u­la­tion and mea­sure­ments.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO062  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO064 Tuning of a Four-vane RFQ for Xi’an 200 MeV Proton Application Facility 838
 
  • X.D. Yu, X. Guan, Q.K. Guo, Y. Lei, P.F. Ma, X.W. Wang, Q.Z. Xing, S.X. Zheng
    TUB, Beijing, People’s Republic of China
  • B.C. Wang, Z.M. Wang, C. Zhao
    NINT, Shannxi, People’s Republic of China
  
  This paper mainly de­scribes the pro­ce­dures and re­sults of tun­ing a four-vane Radio Fre­quency Quadru­pole (RFQ) ac­cel­er­a­tor for the Xi’an 200 MeV Pro­ton Ap­pli­ca­tion Fa­cil­ity (XiPAF) pro­ject. The 3-me­ter-long RFQ will ac­cel­er­ate a 50 keV H− beam from the ECR source to 3 MeV, and de­liver it to the down­stream drift tube linac (DTL) with a peak cur­rent of 5 mA, pulse length of 10-40 μs and max­i­mum rep­e­ti­tion rate of 0.5. The ma­chin­ing, as­sem­bly, and RF tun­ing of the RFQ cav­ity has been com­pleted suc­cess­fully. After tun­ing, the rel­a­tive error of the op­er­at­ing quadru­pole mode field is within ±2.7%, and the di­pole mode com-po­nent is within ±1.9% of the quadru­pole mode. The RFQ now is ready for high-power RF con­di­tion­ing.  
poster icon Poster THPO064 [1.413 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO064  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO066 First High Power Test of the ESS High Beta Elliptical Cavity 841
THOP05   use link to see paper's listing under its alternate paper code  
 
  • H. Li, L. Hermansson, M. Jobs, R.J.M.Y. Ruber, R. Santiago Kern
    Uppsala University, Uppsala, Sweden
  • G. Devanz, T. Hamelin
    CEA/DSM/IRFU, France
  
  ESS, the Eu­ro­pean Spal­la­tion Source, will adopt el­lip­ti­cal multi-cell su­per­con­duct­ing cav­i­ties with a beta value of 0.86 to ac­cel­er­ate the pro­ton beam up to 2 GeV at the last sec­tion of the linac. A 5-cell high-beta cav­ity for ESS pro­ject was tested with high power at FREIA Lab­o­ra­tory. A pulse mode test stand based on a self-ex­cited loop was used in this test. The qual­i­fi­ca­tion of the cav­ity pack­age in­volved a 5-cell el­lip­ti­cal cav­ity, a fun­da­men­tal power cou­pler, a cold tun­ing sys­tem, LLRF sys­tem and a RF sta­tion. These tests rep­re­sented an im­por­tant ver­i­fi­ca­tion be­fore the se­ries pro­duc­tion. This paper pre­sents the test con­fig­u­ra­tion, RF con­di­tion­ing his­tory, first high power per­for­mance and ex­pe­ri­ence of this cav­ity pack­age.  
slides icon Slides THPO066 [1.437 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO066  
About • paper received ※ 14 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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THPO067 Control System and Experiment for RAON HWR Cryomodules 845
 
  • H. Kim, J.W. Choi, C.O. Choi, H. Jang, Y.W. Jo, H.C. Jung, Y. Jung, J.W. Kim, M.S. Kim, Y. Kim, D.Y. Lee, M. Lee, S. Lee, K.T. Seol, K.T. Son
    IBS, Daejeon, Republic of Korea
  
  A pro­to­type of half-wave res­onator (HWR) cry­omod­ules is fab­ri­cated and tested. Ca­bles and tray are in­stalled for hor­i­zon­tal test. The de­sign and the pip­ing and in­stru­men­ta­tion di­a­gram (P&ID) of the HWR cry­omod­ule are pre­sented. The HWR cry­omod­ule is tested with de­vel­oped pro­gram­ma­ble logic con­troller (PLC) and ex­per­i­men­tal physics and in­dus­trial con­trol sys­tem (EPICS) con­trol sys­tems. The heat loads of the HWR cry­omod­ule for sta­tic and dy­namic are mea­sured.  
poster icon Poster THPO067 [0.631 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO067  
About • paper received ※ 10 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO068 AN Effect of Field Emission on Low Beta Superconducting Cavities 849
SPWR011   use link to see paper's listing under its alternate paper code  
 
  • X. Liu, Z. Gao, Y. He, G. Huang
    IMP/CAS, Lanzhou, People’s Republic of China
  
  Su­per­con­duct­ing RF (SRF) tech­nol­ogy is widely ap-plied in par­ti­cle ac­cel­er­a­tors to shorten the ac­cel­er­a­tor length and lower the con­struc­tion price due to its high ac­cel­er­a­tion gra­di­ents with low rf losses. Field emis­sion is the chief lim­i­ta­tion as­so­ci­ated with the sur­face elec­tric field which will fi­nally de­ter­mine the cav­ity per­for­mance dur­ing the op­er­a­tion. The pickup-drop sig­nal caused by field emis­sion se­ri­ously af­fect the sta­ble op­er­a­tion of the su­per­con­duct­ing linac in the Chi­nese ini­tia­tive Ac­cel­era-tor-Dri­ven Sub-crit­i­cal Sys­tem (CiADS) demon fa­cil­ity. Sim­u­la­tions of the field emis­sion ef­fect and ex­per­i­men­tal mea­sure­ments of the pickup-drop sig­nal have been per-formed on the half wave­length res­onator (HWR) cav­ity. And a mod­i­fied de­sign of the pickup an­tenna will be dis­cussed to solve the pickup-drop prob­lem.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO068  
About • paper received ※ 12 September 2018       paper accepted ※ 09 October 2018       issue date ※ 18 January 2019  
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THPO069 The Electromagnetic Optimization of TE-sample Host Cavity at IMP 852
 
  • S.C. Huang, Y. He, T. Tan, S.X. Zhang
    IMP/CAS, Lanzhou, People’s Republic of China
  
  As a part of the re­search and de­vel­op­ment work of thin-film ma­te­ri­als for su­per­con­duct­ing radio fre­quency(SRF) ap­pli­ca­tion in fu­ture ac­cel­er­a­tors at IMP, a 3.9GHz TE sam­ple host cav­ity is being de­vel­oped for the pur­pose of char­ac­ter­iz­ing the RF Prop­erty and the loss mech­a­nism of thin-film ma­te­ri­als, which op­er­ates in the TE011 mode and ac­com­mo­dates disk sam­ple with 110mm di­am­e­ter, the­o­ret­i­cally, the max­i­mum mag­netic field on sam­ple sur­face will go up to 100mT, the res­o­lu­tion of sur­face re­sis­tance on sam­ple will below nOhm by using ther­mom­e­try tech­nique( T-Map­ping). In this paper, the elec­tro­mag­netic op­ti­miza­tion re­sult of TE-sam­ple host cav­ity will be pre­sented, and the de­sign con­sid­er­a­tion of hook tip style cou­pler and T-map­ping sys­tem are also dis­cussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO069  
About • paper received ※ 12 September 2018       paper accepted ※ 08 October 2018       issue date ※ 18 January 2019  
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THPO072 Cryogenic Tests of the Superconducting β=0.069 CH-cavities for the HELIAC-project 855
SPWR010   use link to see paper's listing under its alternate paper code  
 
  • M. Basten, M. Busch, H. Podlech, M. Schwarz
    IAP, Frankfurt am Main, Germany
  • K. Aulenbacher, W.A. Barth, F.D. Dziuba, V. Gettmann, T. Kürzeder, M. Miski-Oglu
    HIM, Mainz, Germany
  • W.A. Barth, M. Heilmann, S. Yaramyshev
    GSI, Darmstadt, Germany
  
  In the fu­ture the ex­ist­ing UNI­LAC (UNI­ver­sal Lin­ear Ac­cel­er­a­tor) at GSI will be most ex­clu­sively used as an in­jec­tor for FAIR to pro­vide short pulse high in­ten­sity heavy ion beams at low rep­e­ti­tion rates [Barth3]. A new su­per­con­duct­ing (sc) con­tin­u­ous wave (cw) high in­ten­sity heavy ion Linac should pro­vide ion beams with max. duty fac­tor above the coulomb bar­rier for the Super Heavy El­e­ment (SHE) pro­gram at GSI. The fun­da­men­tal Linac de­sign com­prises a low en­ergy beam trans­port (LEBT)-sec­tion fol­lowed by a sc Drift Tube Linac (DTL) con­sist­ing of sc Cross­bar-H-mode (CH) struc­tures for ac­cel­er­a­tion up to 7.3 MeV/u [*]. After the suc­cess­ful test and com­mis­sion­ing of the first demon­stra­tor sec­tion with heavy ion beam from the HLI in 2017 [**], the next two sc CH-struc­tures have been con­structed and the first one has been ex­ten­sively tested at cryo­genic tem­per­a­tures at the In­sti­tute for Ap­plied Physics (IAP) at Goethe Uni­ver­sity Frank­furt (GUF). The re­sults of the final cold test of the first CH-struc­ture as well as the next steps re­al­iz­ing a new sc cw heavy ion LINAC at GSI will be pre­sented.
[*]W. Barth et al., "Further investigations for a superconducting cw-Linac at GSI"
[**]W. Barth et al., "First high intensity heavy ion beam tests with a superconducting multi gap CH-cavity"
 		 
poster icon Poster THPO072 [1.150 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO072  
About • paper received ※ 11 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO073 RF Commissioning of the Superconducting 217 MHz CH Cavity for Heavy Ions and First Beam Operation 859
 
  • F.D. Dziuba, K. Aulenbacher, W.A. Barth, V. Gettmann, T. Kürzeder, M. Miski-Oglu
    HIM, Mainz, Germany
  • K. Aulenbacher
    IKP, Mainz, Germany
  • W.A. Barth, M. Heilmann, J. Salvatore, A. Schnase, S. Yaramyshev
    GSI, Darmstadt, Germany
  • M. Basten, M. Busch, H. Podlech, M. Schwarz
    IAP, Frankfurt am Main, Germany
  
  Fu­ture re­search pro­grams at GSI in the field super heavy el­e­ment (SHE) syn­the­sis re­quire high in­tense heavy ion beams above the coulomb bar­rier and high av­er­age par­ti­cle cur­rents. The up­com­ing de­mands ex­ceed the tech­ni­cal op­por­tu­ni­ties of the ex­ist­ing UNI­ver­sal Lin­ear AC­cel­er­a­tor (UNI­LAC). Con­se­quently, a new ded­i­cated su­per­con­duct­ing (sc) con­tin­u­ous wave (cw) linac is cru­cial to keep the SHE re­search pro­gram at GSI com­pet­i­tive on a high level. Re­cently the first linac sec­tion, serv­ing as a pro­to­type to demon­strate the re­li­able op­er­abil­ity of 217 MHz multi gap cross­bar-H-mode (CH) cav­i­ties under a re­al­is­tic ac­cel­er­a­tor en­vi­ron­ment, has been ex­ten­sively tested with a heavy ion beam de­liv­ered from the GSI High Charge State In­jec­tor (HLI). Ful­fill­ing its role as a key com­po­nent of the whole demon­stra­tor setup. The first sc 217 MHz CH cav­ity (CH0) suc­cess­fully ac­cel­er­ated heavy ions up to the de­sign beam en­ergy and even be­yond at high beam in­ten­si­ties and full trans­mis­sion. In this con­tri­bu­tion the rf com­mis­sion­ing and the first beam op­er­a­tion of the cav­ity is pre­sented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO073  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO076 Multiphysics Design Studies of a Superconducting Quarter-wave Resonator at Peking University 863
 
  • M. Chen, S. Chen, A.Q. Cheng, W. Cheng, J.K. Hao, S.W. Quan, F. Zhu
    PKU, Beijing, People’s Republic of China
  
  Funding: This work is supported by National Basic Research Program (2014CB845504)
A 81.25MHz, geo­met­ric β=0.046 quar­ter-wave res­onator has been de­signed and analysed at Peking Uni­ver­sity. This paper mainly pre­sents the multi-physics stud­ies of this cav­ity, in­clude elec­tro­mag­netic de­sign, me­chan­i­cal analy­sis and mul­ti­pact­ing sim­u­la­tion, to pre­dict its be­hav­iour under prac­ti­cal op­er­at­ing process. Var­i­ous trans­verse vi­bra­tion modes of inner con­duc­tor were found under dif­fer­ent fixed con­di­tions and an asym­met­ric short­ing plate was adopted to avoid high pos­si­bil­ity of mul­ti­pact­ing
"quarter-wave resonator"
"multiphysics"
"multipacting"
"frequency detuning"
"stiffening design" 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO076  
About • paper received ※ 12 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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THPO079 RF Test of Standing Wave Deflecting Cavity with Minimized Level of Aberrations 866
THOP10   use link to see paper's listing under its alternate paper code  
 
  • V.V. Paramonov
    RAS/INR, Moscow, Russia
  • K. Flöttmann
    DESY, Hamburg, Germany
  
  For di­ag­nos­tic of lon­gi­tu­di­nal dis­tri­b­u­tion of elec­trons in unique REGAE bunches is ap­plied a spe­cially de­vel­oped de­flect­ing struc­ture with min­i­mized level of aber­ra­tions in the field dis­tri­b­u­tion and im­proved RF ef­fi­ciency. Short de­flect­ing cav­ity was con­structed and in­stalled now in REGAE beam line. The cav­ity is tested at op­er­a­tional level of RF power. The main dis­tinc­tive fea­tures of the cav­ity are men­tioned and ob­tained re­sults are re­ported.  
slides icon Slides THPO079 [1.803 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO079  
About • paper received ※ 11 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO080 Design Validation of a Chopping and Deflecting System for the High Current Injector at IUAC 869
 
  • S. Kedia, R. Ahuja, R. Kumar, R. Mehta
    IUAC, New Delhi, India
  
  A chop­ping and de­flect­ing sys­tem has been de­signed and de­vel­oped to pro­vide the chopped beam with var­i­ous rep­e­ti­tion rates at the IUAC ex­per­i­men­tal fa­cil­i­ties. It con­sists of four pairs of de­flect­ing plates with in­creas­ing gap from 15 mm to 21 mm to max­i­mize the ef­fec­tive elec­tric field, pre­serve the beam emit­tance and to max­i­mize the trans­mis­sion ef­fi­ciency within the same volt­age con­di­tions. The de­sign of CDS has been val­i­dated with var­i­ous sim­u­la­tion codes like CST MWS, Solid Works, Python and TRACE 3D. The de­flect­ing plates have been fab­ri­cated, and as­sem­bled with in the de­sign ac­cu­racy of 100 mi­crons. A vac­uum cham­ber has been de­signed and fab­ri­cated to in­cor­po­rate the de­flec­tor plate as­sem­bly. The CDS unit has been in­stalled in the Low En­ergy Ion Beam Fa­cil­ity at the IUAC to val­i­date the de­sign value of ion beam de­flec­tion. A slit has been in­stalled to cut the de­flected charge par­ti­cles. Since the pulse power elec­tron­ics re­quired for chop­ping is presently under de­sign we have used DC volt­age across the four pairs of de­flect­ing plates and amount of de­flec­tion was mea­sured ac­cord­ingly. The de­sign, de­vel­op­ment, and DC beam test will be dis­cussed in the ar­ti­cle.  
poster icon Poster THPO080 [2.037 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO080  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO082 Physical Design of a Rectangular RF Deflector for Ultrashort Bunch Length Measurement 872
SPWR028   use link to see paper's listing under its alternate paper code  
 
  • J. Bai, Q.S. Chenpresenter, K. Fan
    HUST, Wuhan, People’s Republic of China
  
  Cylin­dri­cal de­flec­tors which are now widely used for bunch length mea­sure­ment suf­fer from the de­gen­er­a­tion of po­lar­iza­tion, while rec­tan­gu­lar de­flec­tors can sep­a­rate po­lar­iza­tion mode eas­ily. This paper is fo­cused on the study of a one-cell rec­tan­gu­lar de­flec­tor, which is con­sid­er­ably dif­fer­ent from cylin­dri­cal struc­ture or multi-cell struc­ture. A one-cell struc­ture is free of π mode re­stric­tion and can achieve higher de­flec­tion ef­fi­ciency per unit length. The pro­posed scheme is ex­pected to achieve time res­o­lu­tion bet­ter than 200fs with the dri­ving power less than 1MW. Cav­ity op­ti­miza­tion and beam dy­namic sim­u­la­tion are in­tro­duced in this paper.  
poster icon Poster THPO082 [0.484 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO082  
About • paper received ※ 11 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO083 Transverse Deflecting Cavity for Longitudinal Beam Diagnostics at BERLinPro 875
 
  • G. Kourkafas, T. Kamps, A. Neumann
    HZB, Berlin, Germany
  • B. Keune
    RI Research Instruments GmbH, Bergisch Gladbach, Germany
  
  The Berlin En­ergy Re­cov­ery Linac Pro­to­type (BERLinPro) at Helmholtz Zen­trum Berlin (HZB) aims to de­liver a con­tin­u­ous-wave elec­tron beam of high av­er­age cur­rent (100 mA) and bril­liance (nor­mal­ized emit­tance below 1 mm mrad). The achieve­ment of these am­bi­tious goals ne­ces­si­tates a thor­ough de­ter­mi­na­tion of the bunch pa­ra­me­ters after the first ac­cel­er­a­tion stages, namely the pho­toin­jec­tor and the suc­ceed­ing booster mod­ule. For the mea­sure­ment of pri­mar­ily the bunch du­ra­tion and sub­se­quently the lon­gi­tu­di­nal phase space and trans­verse slice emit­tance, a sin­gle-cell 1.3-GHz TM110-like mode ver­ti­cally de­flect­ing cav­ity was man­u­fac­tured by RI Re­search In­stru­ments GmbH, fol­low­ing the re­spec­tive de­sign de­vel­oped for the Cor­nell ERL in­jec­tor. This ar­ti­cle sum­ma­rizes the de­sign pa­ra­me­ters, man­u­fac­tur­ing pro­ce­dure and test­ing of this pulsed RF res­onator, to­gether with the ex­pected tem­po­ral mea­sure­ment res­o­lu­tion for the nom­i­nal beam en­er­gies at the ini­tial ac­cel­er­a­tion stages of BERLinPro.  
poster icon Poster THPO083 [1.396 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO083  
About • paper received ※ 11 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO084 BPM Time of Flight Measurements for Setting-up the RF Cavities of the CERN Linac4 879
 
  • M. Bozzolan
    CERN, Geneva, Switzerland
  
  The newly con­structed H− LINAC4 at CERN has re­cently com­pleted its first ex­tended re­li­a­bil­ity run. It is equipped with Beam Po­si­tion Mon­i­tors (BPMs) based on shorted-stripline pick-up elec­trodes to mea­sure both po­si­tion and Time of Flight (ToF). The ToF, in turn used to cal­cu­late the ki­netic en­ergy of the beam, is de­ter­mined through sig­nal phase shift mea­sure­ments be­tween pairs of BPMs. ToF mea­sure­ments are per­formed by scan­ning of the phase of the RF in­jected into the cav­i­ties to find the nom­i­nal RF set­tings for op­ti­mal beam ac­cel­er­a­tion. This paper fo­cuses on the tech­ni­cal as­pects of the ToF mea­sure­ment as well as on the re­sults ob­tained dur­ing beam com­mis­sion­ing and their com­par­i­son with beam dy­nam­ics sim­u­la­tions.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO084  
About • paper received ※ 12 September 2018       paper accepted ※ 08 October 2018       issue date ※ 18 January 2019  
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THPO086 Beam Loss and Average Beam Current Measurements Using a CWCT 882
 
  • F. Stulle, H. Bayle, J.F. Bergoz, T. Delaviere, L. Dupuy
    BERGOZ Instrumentation, Saint Genis Pouilly, France
  • P. Forck, M. Witthaus
    GSI, Darmstadt, Germany
  • D. Vandeplassche
    SCK•CEN, Mol, Belgium
  • J.X. Wu
    IMP/CAS, Lanzhou, People’s Republic of China
  
  The CWCT is a novel in­stru­ment adapted to an ac­cu­rate av­er­age cur­rent de­ter­mi­na­tion of bunched CW beams or macro pulses. By com­bin­ing a high-droop cur­rent trans­former with novel elec­tron­ics for sig­nal analy­sis, an out­put sig­nal band­width of DC to about 500kHz and a cur­rent res­o­lu­tion down to the mi­cro-am­pere level are achieved. Beam cur­rent fluc­tu­a­tions are fol­lowed within mi­crosec­onds, per­mit­ting fast de­tec­tion of beam loss. These char­ac­ter­is­tics ren­der the CWCT an ideal in­stru­ment for HPPAs, for ex­am­ple ADS linacs, and other pro­ton or ion ac­cel­er­a­tors. We pre­sent the CWCT prin­ci­ple and the CWCT per­for­mance achieved in beam ex­per­i­ments at UNI­LAC, GSI.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO086  
About • paper received ※ 11 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO090 The Analysis of Module Failure in High Solid-state Amplifier for High Current RFQ 886
 
  • L.P. Sun, Y. He, G. Huang, C.X. Li, L. Lu, A. Shi, L.B. Shi, X.B. Xu, H.W. Zhao
    IMP/CAS, Lanzhou, People’s Republic of China
  
  New ac­cel­er­a­tor RF sys­tem was up­graded to the solid-state am­pli­fier in ADS pro­ject due to its sta­ble, sus­tain­able and re­li­able. Until now, newest 80kW SSA was adopted in IMP, op­er­at­ing in 162.5MHz, and over 120 power mod­ules were com­bined through sev­eral syn­the­siz­ers for 80kW out­put. but since too many mod­ules were op­ti­mized for am­pli­tude and phase in the same time, one or some fail­ure of cir­cu­la­tor will lead to in­jure of whole RF sys­tem, when wave­length meets a spe­cific con­di­tion, in­jure would turn out se­vere ac­ci­dent and heavy loss. In this paper, an­a­lyz­ing and sim­u­lat­ing the multi-level syn­thetic ma­trix was the im­por­tant method for ADS ac­ci­dent hap­pened in June 20. 2017, the fail­ure sim­u­lated re­sults for RF am­plify links under the spe­cific cir­cum­stances also was pre­sented si­mul­ta­ne­ously.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO090  
About • paper received ※ 17 September 2018       paper accepted ※ 31 October 2018       issue date ※ 18 January 2019  
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THPO091 90 kW Solid-state RF Amplifier with a TE011-mode Cavity Power-combiner at 476 MHz 889
THOP07   use link to see paper's listing under its alternate paper code  
 
  • Y. Otake, T. Asaka, T. Inagaki
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
  • S. Aizawa, K. Nagatsuka, T. Okuyama, K. Sato, H. Yamada
    Nihon Koshuha Co. Ltd, Yokohama, Japan
  
  Solid-state RF am­pli­fiers, which have long life­times and small fail­ures, are the re­cent trend of re­li­able and sta­ble high-power rf sources for par­ti­cle ac­cel­er­a­tors. Hence, we de­signed a 90kW solid-state am­pli­fier with an ex­treme low-loss TE011 mode cav­ity (Q0=100, 000) power-com­biner op­er­ated at 476 MHz and a 6 us pulse width. De­vel­op­ing this am­pli­fier is for re­place­ment of an IOT rf am­pli­fier, at the X-ray free-elec­tron laser, SACLA. In SACLA, highly RF phase and am­pli­tude sta­bil­i­ties of less than 0.02 deg. and 10-4 in rms are nec­es­sary to sta­ble las­ing within a 10 % in­ten­sity fluc­tu­a­tion. The am­pli­fier com­prises a drive am­pli­fier, a reen­trant cav­ity rf power di­vider, 100 final am­pli­fiers with a 1 kW out­put each and a TE011 mode cav­ity com­biner. Wa­ter-cool­ing within 10 mK and a DC power sup­ply with a noise of less than -100 dBV at 10 Hz for the am­pli­fier is nec­es­sary to re­al­ize the pre­vi­ously men­tioned sta­bil­i­ties. Based on the test re­sults of the am­pli­fier, the above-men­tioned spec­i­fi­ca­tions with the ex­treme low-loss are promis­ing. The am­pli­fier also al­lows us to op­er­ate in pulsed and CW rfs for linacs and ring ac­cel­er­a­tors. We re­port the per­for­mance of the 90kW am­pli­fier.  
slides icon Slides THPO091 [1.750 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO091  
About • paper received ※ 06 September 2018       paper accepted ※ 09 October 2018       issue date ※ 18 January 2019  
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THPO092 LCLSII Fundamental Power Coupler Manufacturing Status and Lesson Learned 893
 
  • S. Sierra, G. Garcin, Ch.L. Lievin, G. Vignette, I. Yao Leclerc
    TED, Velizy-Villacoublay, France
  • M. Knaak, M. Pekeler
    RI Research Instruments GmbH, Bergisch Gladbach, Germany
  
  Thales and RI Re­search In­stru­ment have man­u­fac­tured and as­sem­bled half of the power cou­plers for the LCLSII pro­ject. This paper re­mains main char­ac­ter­is­tics of these cou­pler. It will also de­scribe main chal­lenges that were over­come among them, thick­ness of cop­per coat­ing on Warm In­ter­nal Con­duc­tor at 150µm and lessons learned dur­ing the man­u­fac­tur­ing phase of these cou­plers. The paper will also pro­pose some pos­si­ble op­ti­miza­tion for a fu­ture mass pro­duc­tion of such com­po­nents and pa­ra­me­ters which could be rel­e­vant for a bet­ter un­der­stand­ing link to the sta­tis­tic re­sults ob­tained.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO092  
About • paper received ※ 10 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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THPO093 Status and Results Obtained on a RF Conditioning Test Bench for 704 MHz Couplers in the Frame of ESS Project 895
 
  • S. Sierra, Y. Amal, Ch.L. Lievin, I. Yao Leclerc
    TED, Velizy-Villacoublay, France
  • M.E. Chahbazian, J.G. DeOliveira, A.G. Goeury, L.J. Nennig, S.P. Petitjean
    GERAC Thales, Le Barp, France
  
  Thales and Gerac are de­vel­op­ing a test bench able to make the RF con­di­tion­ing of the Fun­da­men­tal Power Cou­plers at 704 MHz in the frame of the ESS pro­ject for CEA. The sta­tus of the de­vel­op­ments of the test bench is de­scribed in­clud­ing the mod­u­la­tor, kly­stron and all rel­a­tive equip­ments. The paper will also de­scribes the re­sults ob­tained at the date of pre­sen­ta­tion.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO093  
About • paper received ※ 10 September 2018       paper accepted ※ 08 October 2018       issue date ※ 18 January 2019  
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THPO095 Present Status of Capacitor-charging Power Supplies for Klystron Modulators in SuperKEKB Injector Linac 898
 
  • M. Kawamura, M. Akemoto, S. Fukuda, H. Honma, S. Michizono, H. Nakajima, T. Natsui, T. Shidara
    KEK, Ibaraki, Japan
  • H. Akikawa, O. Endo, K. Sato
    Nihon Koshuha Co. Ltd, Yokohama, Japan
  
  The ca­pac­i­tor-charg­ing power sup­plies (CCPSs) for the kly­stron mod­u­la­tors have been de­vel­oped from 2002 in the Su­perKEKB in­jec­tor linac. The spec­i­fi­ca­tions are that the out­put volt­age is 43kV, the charg­ing power is 30kJ/s, and the out­put volt­age sta­bil­ity is 0.2%p-p. Being used in the old fa­cil­ity, their sizes are re­stricted in 480mm x 680 mm x 760mm. After var­i­ous mod­i­fi­ca­tions, the 13 CCPSs in the linac have been op­er­ated with no fault since last Oc­to­ber. The pre­sent sta­tus of the CCPSs, in­clud­ing the out­lines, spec­i­fi­ca­tions, and the mod­i­fi­ca­tions against the faults, are de­scribed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO095  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO096 Design Study of a High Efficiency Klystron for SuperKEKB Linac 901
 
  • F. Qiu, S. Fukuda, S. Matsumoto, T. Matsumoto, T. Miura, T. Natsui
    KEK, Ibaraki, Japan
  
  The in­jec­tor lin­ear ac­cel­er­a­tor (linac) for the Su­perKEKB par­ti­cle ac­cel­er­a­tor re­quires a higher ef­fi­ciency kly­stron than the cur­rently used 50 MW, S-band, pulsed unit (PV3050/E3730), which op­er­ates at the same volt­age, to in­crease the power re­dun­dancy. The ef­fi­ciency is ex­pected to im­prove from the cur­rently ob­served 45% to more than 60%. We pro­pose a type of high ef­fi­ciency kly­stron using novel bunch­ing mech­a­nisms. The 1-D disk model based code is used for pre­lim­i­nary op­ti­miza­tion of the tube pa­ra­me­ters; these pa­ra­me­ters are fur­ther checked by 2-D codes known as field charge in­ter­ac­tion (FCI) and MAGIC. In this paper, the de­sign con­sid­er­a­tion of the high ef­fi­ciency kly­stron is pre­sented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO096  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO097 Recent Results for Study of Ceramic and Copper Plating for Power Couplers 905
 
  • Y. Yamamoto, E. Kako, S. Michizono
    KEK, Ibaraki, Japan
  • E. Cenni
    CEA/IRFU, Gif-sur-Yvette, France
  • A. Four
    CEA/DRF/IRFU, Gif-sur-Yvette, France
  • Y. Okii
    Nomura Plating Co, Ltd., Osaka, Japan
  
  KEK has con­ducted a sur­vey to se­lect an op­ti­mum ce­ramic after with­drawal by a do­mes­tic man­u­fac­tur­ing com­pany two years ago. For this se­lec­tion, there are four im­por­tant items on the prop­er­ties of ce­ramic; that is, rel­a­tive per­mit­tiv­ity, di­elec­tric loss tan­gent, sur­face and vol­ume re­sis­tance, and sec­ondary elec­tron emis­sion co­ef­fi­cient. For mea­sure­ments of these pa­ra­me­ters, five kinds of ce­ramic sam­ples sup­plied from three com­pa­nies were mea­sured using three kinds of mea­sure­ment sys­tems. For mea­sure­ment of sec­ondary elec­tron emis­sion, scan­ning elec­tron mi­cro­scope (SEM) with beam blank­ing sys­tem was used. On the other hand, resid­ual re­sis­tiv­ity ratio (RRR) for cop­per plat­ing, which is the most im­por­tant item for qual­ity con­trol, has also been car­ried out while chang­ing plat­ing thick­ness and acid tem­per­a­ture. In this re­port, the re­cent re­sults for these stud­ies will be pre­sented in de­tailed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO097  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO100 Development of a 1.5 GHz High-power CW Magnetron for SRF Accelerator 908
 
  • L. Wenliang
    College of Engineering and Applied Sciences for Nanjing University, Nanjing, People’s Republic of China
  • S. An, Y.J. Ke, S. Lingbin, Z. Pengjiao, L. Youchun, L. Zhao, B.Z. Zhou
    PLAI, Nanjing, People’s Republic of China
  • J.Z. Li, L.P. Zhang, Hou, R. Rui
    ADS, Jiangsu Province, People’s Republic of China
  
  An 1.5 GHz, 13.5 kW CW high-power mag­netron for a su­per­con­duct­ing RF ac­cel­er­a­tor has been de­vel­oped by An­desun Tech­nol­ogy Group Co., Ltd. with Nan­jing Sanle Elec­tronic In­for­ma­tion In­dus­try Group Co., Ltd., in order to re­place the kly­stron, that could re­duce the power source cost to about one-third. The cav­ity, out­put power an­tenna and cou­pling door-nob have been op­ti­mized by using CST Stu­dio. Test­ing re­sults have shown that the res­o­nance fre­quency and out­put power have met the re­quire­ments, and the ef­fi­ciency of the mag­netron is higher that 78.45%.  
poster icon Poster THPO100 [0.574 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO100  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO102 Design Studies of Output Window for CEPC Klystron 911
 
  • Z.J. Lu, Y.L. Chi, S. Fukuda, G. Pei, S. Pei, S.C. Wang, O. Xiao, U. N. Zaib, Z.S. Zhou
    IHEP, Beijing, People’s Republic of China
  • S. Fukuda
    KEK, Ibaraki, Japan
  
  A high power and high ef­fi­ciency kly­stron of the 650MHz, 800kW CW kly­stron for the Cir­cu­lar Elec­tron Positron Col­lider (CEPC) is de­signed and de­vel­oped at IHEP. This paper pre­sents the de­sign and sim­u­la­tion for the high power coax­ial win­dow for it. Plan of the hot test (high power test­ing be­fore in­stalling to the kly­stron) are also de­scribed. Sim­u­la­tion soft­ware of CST, ANSYS and Mul­ti­pac 2.1 are used for de­sign of win­dow mi­crowave struc­ture, ther­mal analy­sis and mul­ti­pact­ing ef­fects. We ob­tained the good sim­u­la­tion re­sults suc­ces­sively; the coax­ial win­dow S-pa­ra­me­ter analy­sis, has re­vealed a low re­flec­tion at the op­er­at­ing fre­quency of 650 MHz. The ther­mal sim­u­la­tion shows a good tem­per­a­ture dis­tri­b­u­tion under the cw 800kW prop­a­ga­tion; max­i­mum tem­per­a­ture has been found to be 33 °C at ce­ramic with water cool­ing in the inner and outer con­duc­tor. The mul­ti­pact­ing at the win­dow is pos­si­ble source of the fail­ure and it is shown that mul­ti­pact­ing has less chance to be hap­pened on the sur­face of ce­ramic.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO102  
About • paper received ※ 12 September 2018       paper accepted ※ 31 October 2018       issue date ※ 18 January 2019  
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THPO103 Application of Solid State Amplifiers in ADS Project at IHEP 914
 
  • O. Xiao
    Institute of High Energy Physics (IHEP), People’s Republic of China
  • Y.L. Chi, N. Gan, X. Ma, Z.S. Zhou
    IHEP, Beijing, People’s Republic of China
  
  The solid state am­pli­fier is an im­por­tant part of the RF power source sys­tem of ADS pro­ject at IHEP. Three kinds of solid state am­pli­fier with dif­fer­ent power and fre­quency have been ap­plied. In this paper, the spec­i­fi­ca­tions of solid state am­pli­fier are pre­sented. In ad­di­tion, the prin­ci­ple of break­down of power mod­ules dur­ing the high power test of cou­pler are an­a­lyzed.  
poster icon Poster THPO103 [0.195 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO103  
About • paper received ※ 17 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO104 Development of 150.4MHz Continuous Wave Solid-state Amplifier 917
 
  • L. Zhao
    Nanjing University of Aeronautics and Astronautics, Jiangning, People’s Republic of China
  • S. An, Y.J. Ke, Z. Pengjiao, L. Wenliang, B.Z. Zhou
    PLAI, Nanjing, People’s Republic of China
  
  A 150.4MHz to 155.4MHz, 300W con­tin­u­ous wave solid-state am­pli­fier as an ac­cel­er­a­tor power source has been de­vel­oped by us. In order to in­crease the life­time of MOS­FET and meet the re­quire­ments of every pa­ra­me­ters, Drain volt­age and qui­es­cent cur­rent is set at a bet­ter point with a well-de­signed heat dis­si­pa­tion struc­ture, we make the solid state am­pli­fier sta­ble in per­for­mance. Tak­ing the mi­crowave leak­age into ac­count, the chas­sis struc­ture is op­ti­mized and de­signed, and the mi­crowave ab­sorp­tion de­vice is adopted to make the struc­ture com­pact, pro­tect other parts not af­fected by the mi­crowave leak­age. After the as­sem­bly is com­pleted, the work­ing pa­ra­me­ters meet the de­sign re­quire­ments very well. The MOS­FET flange tem­per­a­ture and out­put pa­ra­me­ters meet the de­sign re­quire­ments.  
poster icon Poster THPO104 [1.405 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO104  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO107 High Power Coupler R&D for Superconducting CH-cavities 920
SPWR025   use link to see paper's listing under its alternate paper code  
 
  • J. List, K. Aulenbacher, W.A. Barth, F.D. Dziuba, V. Gettmann, T. Kürzeder, M. Miski-Oglu
    HIM, Mainz, Germany
  • K. Aulenbacher
    IKP, Mainz, Germany
  • W.A. Barth, M. Heilmann, J. Salvatore, A. Schnase, S. Yaramyshev
    GSI, Darmstadt, Germany
  • M. Basten, M. Busch, H. Podlech, M. Schwarz
    IAP, Frankfurt am Main, Germany
  
  The up­com­ing de­mands of the fu­ture re­search pro­grams at GSI ex­ceed the tech­ni­cal op­por­tu­ni­ties of the ex­ist­ing UNI­ver­sal Lin­ear AC­cel­er­a­tor (UNI­LAC). Be­sides, the ma­chine will be ex­clu­sively used as an in­jec­tor for FAIR (Fa­cil­ity for An­tipro­ton and Ion Re­search) pro­vid­ing high power heavy ion beams at a low rep­e­ti­tion rate for in­jec­tion into the syn­chro­tron. A new ded­i­cated su­per­con­duct­ing (sc) con­tin­u­ous wave (cw) Linac is cru­cial to keep the re­search pro­gram com­pet­i­tive. The first part of the cw-linac, com­pris­ing a 217 MHz multi gap Cross­bar-H-mode (CH) cav­ity sur­rounded by two sc so­le­noids in­side a cryo­stat, al­ready served as a pro­to­type demon­strat­ing re­li­able op­er­abil­ity in a re­al­is­tic ac­cel­er­a­tor en­vi­ron­ment. A suf­fi­cient high power RF-cou­pling con­cept is needed to feed this newly de­vel­oped cw-RF cav­ity with up to 5 kW of RF-power. A high power cou­pler test stand was re­cently built to pro­vide for a test­ing en­vi­ron­ment; fur­ther up­grade mea­sures of this test area are fore­seen. This con­tri­bu­tion deals with the re­cent cou­pler R&D for the demon­stra­tor set up. Be­sides sim­u­la­tions of ther­mal losses at the cou­pler (in­side the RF-cav­ity) will be shown as well.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO107  
About • paper received ※ 12 September 2018       paper accepted ※ 19 September 2018       issue date ※ 18 January 2019  
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THPO108 Development of an High Gradient Side Coupled Cavity for PROBE 924
THOP08   use link to see paper's listing under its alternate paper code  
 
  • S. Pitman, R. Apsimonpresenter, G. Burt
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • N. Catalán Lasheras, A. Grudiev, W. Wuensch
    CERN, Geneva, Switzerland
  • H.L. Owen
    UMAN, Manchester, United Kingdom
  
  The PROBE pro­ject aims to de­velop a high gra­di­ent pro­ton ac­cel­er­a­tor for pro­tons with en­ergy around 250-350 MeV for pro­ton ra­di­og­ra­phy. De­tailed stud­ies have shown that the op­ti­mum de­sign is a side cou­pled cav­ity at S-band. With an aper­ture of 8 mm a gra­di­ent of 54 MV/m can be ob­tained with 13 MW of RF power in a 30 cm struc­ture. A pro­to­type cav­ity has been ma­chined by VDL and dif­fu­sion bonded by Body­cote. We pre­sent ini­tial mea­sure­ments of the pro­to­type.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO108  
About • paper received ※ 17 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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THPO109 A New Spherical Pulse Compressor Working with Degenerated "Whispering Gallery" Mode 928
SPWR023   use link to see paper's listing under its alternate paper code  
THOP09   use link to see paper's listing under its alternate paper code  
 
  • Z.B. Li, W. Fang, Q. Gu, Z.T. Zhao
    SINAP, Shanghai, People’s Republic of China
  • A. Grudiev
    CERN, Geneva, Switzerland
  
  CLIC is fo­cus­ing on the Com­pact Lin­ear Col­lider. To ob­tain a rel­a­tively high ac­cel­er­at­ing gra­di­ent, CLIC uti­lizes Pulse Com­pres­sors to in­crease the input power of ac­cel­er­a­tors. This work is to make an al­ter­na­tive de­sign for CLIC pulse com­pres­sion scheme. There are sev­eral kinds of pulse com­pres­sor: SLED, BOC, SLED-Ⅱ, spher­i­cal pulse com­pres­sor and so on. Usu­ally, a spher­i­cal cav­ity, in­clud­ing BOC, can offer a higher Q fac­tor com­pared with a cylin­dri­cal cav­ity. This de­sign uti­lizes a spher­i­cal cav­ity work­ing with de­gen­er­ated Whis­per­ing Gallery mode.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO109  
About • paper received ※ 11 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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THPO111 The Test of RF Breakdowns of CPHS RFQ 931
 
  • W.B. Ye, C. Cheng, X. Guan, J. Shi, X.W. Wang, Q.Z. Xing, S.X. Zheng
    TUB, Beijing, People’s Republic of China
  • M.C. Wang
    NINT, Shannxi, People’s Republic of China
  
  The high ac­cel­er­at­ing gra­di­ent is sig­nif­i­cant for a com­pact lin­ear ac­cel­er­a­tor, and RF break­downs is a lim­i­ta­tion for the high gra­di­ent. This work aims to re­search RF break­downs of a 325MHz pro­ton Radio Fre­quency Quadru­pole (RFQ) ac­cel­er­a­tor of the Com­pact Pulsed Hadron Source（CPHS）. The break­down rate (BDR) of the RFQ has been mea­sured. Break­down wave­forms have been recorded, which have been used for count­ing break­down time dis­tri­b­u­tion and an­a­lyz­ing the lo­ca­tion of RF break­downs.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO111  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO113 Design of 4 Ampere S-Band Linac Using Slotted Iris Structure for Hom Damping 934
 
  • J. Pang, S. Chen, X. He
    CAEP/IFP, Mainyang, Sichuan, People’s Republic of China
  • S. Pei, H. Shi, J.R. Zhang
    IHEP, Beijing, People’s Republic of China
  
  An S-band LINAC with the op­er­at­ing fre­quency of 2856 MHz and beam cur­rent of 4 A was de­signed for flash X-ray ra­di­og­ra­phy for hy­dro­dy­namic test. The op­ti­miza­tion of the pa­ra­me­ters of the LINAC was processed to ob­tain the min­i­mum beam ra­dius and the max­i­mum en­ergy ef­fi­ciency. For the pur­pose of re­duc­ing the beam or­bits off­set at the exit of LINAC, a slot­ted iris ac­cel­er­at­ing struc­ture would be em­ployed to sup­press the trans­verse Higher Order Modes (HOMs) by cut­ting four ra­dial slots in the iris to cou­ple the HOMs to SiC loads. In this paper, we pre­sent the de­sign of the LINAC and the re­sults of beam dy­namic analy­sis.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO113  
About • paper received ※ 10 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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THPO115 Consolidation and Extension of the High-gradient LINAC RF Technology at PSI 937
 
  • P. Craievich, M. Bopp, H.-H. Braun, A. Citterio, H. Fitze, T. Garvey, T. Kleeb, F. Löhl, F. Marcellini, M. Pedrozzi, J.-Y. Raguin, L. Rivkin, K. Rolli, R. Zennaro
    PSI, Villigen PSI, Switzerland
  
  For Swiss­FEL a novel pro­duc­tion process for high-gra­di­ent, high-pre­ci­sion C-band ac­cel­er­at­ing struc­tures had been de­vel­oped at PSI and was im­ple­mented for se­ries pro­duc­tion in col­lab­o­ra­tion with in­dus­try. The cop­per parts of the struc­tures are ma­chined and brazed re­ly­ing on a ul­tra-high pre­ci­sion man­u­fac­tur­ing process and tight me­chan­i­cal tol­er­ances; no RF tun­ing meth­ods are ap­plied dur­ing or after pro­duc­tion. So far none of the struc­tures of the se­ries pro­duc­tion failed dur­ing RF power con­di­tion­ing and op­er­a­tion in the Swiss­FEL fa­cil­ity. After com­plet­ing the se­ries pro­duc­tion for Swiss­FEL PSI started col­lab­o­ra­tions with CERN, ELET­TRA and DESY for ap­ply­ing the pro­duc­tion process and re­lated know-how to other fre­quen­cies, namely S-band (3 GHz) and X-band (12 GHz). This paper gives an overview on the on­go­ing and planned R\&D ac­tiv­i­ties and re­sults ob­tained so far.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO115  
About • paper received ※ 11 September 2018       paper accepted ※ 19 September 2018       issue date ※ 18 January 2019  
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THPO116 Space-Charge Dominated Photoemission in High Gradient Photocathode RF Guns 941
THOP11   use link to see paper's listing under its alternate paper code  
 
  • Y. Chen, P. Boonpornprasert, J.D. Good, M. Groß, H. Huck, I.I. Isaev, D.K. Kalantaryan, C. Koschitzki, M. Krasilnikov, O. Lishilin, G. Loisch, D. Melkumyan, R. Niemczyk, A. Oppelt, H.J. Qian, Y. Renier, F. Stephan
    DESY Zeuthen, Zeuthen, Germany
  • H. Chen, Y. C. Du, W.-H. Huang, C.-X. Tang, Q.L. Tian, L.X. Yan
    TUB, Beijing, People’s Republic of China
  • H. De Gersem, E. Gjonaj
    TEMF, TU Darmstadt, Darmstadt, Germany
  • M. Dohlus
    DESY, Hamburg, Germany
  • S. A. Schmid
    Institut Theorie Elektromagnetischer Felder, TU Darmstadt, Darmstadt, Germany
  
  The cath­ode emis­sion physics plays a cru­cial role in the over­all beam dy­nam­ics in the gun. In­ter­plays be­tween in­tri­cate emis­sion mech­a­nisms in the cath­ode vicin­ity strongly in­flu­ence the cath­ode quan­tum ef­fi­ciency (QE) and the in­trin­sic emit­tance. The pres­ence of strong space-charge ef­fects in high gra­di­ent RF guns fur­ther com­pli­cates the emis­sion process. A proper mod­el­ing of pho­toe­mis­sion and a care­ful treat­ment of the space-charge con­tri­bu­tion is thus of great ne­ces­sity to un­der­stand­ing the for­ma­tion of the beam slice emit­tance. In this ar­ti­cle, emis­sion mea­sure­ments are car­ried out using the L-band ce­sium-tel­luride pho­to­cath­ode RF gun at the Photo In­jec­tor Test Fa­cil­ity at DESY in Zeuthen (PITZ) and the S-band cop­per pho­to­cath­ode RF gun at Ts­inghua Uni­ver­sity. Fol­low­ing the Dow­ell model a sim­ple so-called space-charge it­er­a­tion ap­proach is de­vel­oped and used to de­ter­mine the QE through tem­po­ral and spa­tial-de­pen­dent elec­tro­mag­netic fields. An im­pact of the space-charge cool­ing on the ther­mal emit­tance is pre­sented. Mea­sure­ment data are shown and dis­cussed in com­par­isons to pre­lim­i­nary sim­u­la­tion re­sults.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO116  
About • paper received ※ 11 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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THPO117
 96Zr Beam Acceleration for Isobar Experiment in RHIC  
THOP12   use link to see paper's listing under its alternate paper code  
 
  • M. Okamura, E.N. Beebe, S. Ikeda, T. Kanesue, D. Rapariapresenter
    BNL, Upton, Long Island, New York, USA
  • H. Haba
    RIKEN Nishina Center, Wako, Japan
  
  Funding: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
To in­ves­ti­gate chi­ral mag­netic ef­fect, 96Zr and 96Ru beams have been ac­cel­er­ated at rel­a­tivis­tic heavy ion col­lider (RHIC) in Run18 at Brookhaven Na­tional Lab­o­ra­tory (BNL). 96Zr and 96Ru beams were pro­vided from elec­tron beam ion source (EBIS) in­jec­tor and tan­dem Van de Graaff, repec­tively. In the pre­sen­ta­tion, 96zr beam pro­duc­tion and ac­cel­er­a­tion will be re­ported. The EBIS in­jec­tor con­sist of laser ion source, EBIS as a charge breeder, 300 keV/u RFQ and 2 MeV/u IH-DTL. The nat­ural abun­dance of 96Zr is only 2.8 % and about 50 % is oc­cu­pied by 90Zr. To ob­tain suf­fi­cient beam cur­rent, mass num­ber 96 en­riched ma­te­r­ial was used. Un­for­tu­nately, only avail­able form of the en­riched ma­te­r­ial is oxide pow­der which does not suit for laser ion source tar­get. We have es­tab­lished sin­ter­ing tech­nique of ZrO2 pow­der to make a solid piece which can be in­stalled into the laser ion source. The in­duced singly charged Zr and oxy­gen were de­liv­ered to the EBIS to be ion­ized fur­ther. We have op­ti­mized laser ir­ra­di­a­tion con­di­tion, EBIS con­fine­ment time, op­er­at­ing con­di­tion of the linacs to max­i­mized the per­for­mance of the linac based in­jec­tor. The de­tailed R&D works will be pre­sented in the con­fer­ence. 		 
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THPO118 Beam Transverse Coupling and 4D Emittance Measurement Simulation Studies for PITZ 945
 
  • Q.T. Zhao, M. Krasilnikov, H.J. Qian, F. Stephan
    DESY Zeuthen, Zeuthen, Germany
  • Q.T. Zhao
    IMP/CAS, Lanzhou, People’s Republic of China
  
  The Photo In­jec­tor Test Fa­cil­ity at DESY, Zeuthen site (PITZ) was built to test and op­ti­mize high bright­ness elec­tron sources for Free Elec­tron Lasers (FELs) like FLASH and the Eu­ro­pean XFEL. Al­though the beam emit­tance has been op­ti­mized and ex­per­i­men­tally demon­strated to meet the re­quire­ments of FLASH and XFEL, trans­verse beam asym­me­tries were ob­served dur­ing op­er­a­tion of the RF guns. Based on pre­vi­ous stud­ies [1], the beam asym­me­tries most prob­a­bly stem from beam trans­verse cou­pling by quadru­pole field er­rors in the gun sec­tion. A pair of nor­mal and skew gun quadrupoles was suc­cess­fully used for re­duc­ing the beam asym­me­tries in ex­per­i­ment. In this paper, we dis­cuss the beam trans­verse cou­pling be­tween X and Y planes due to quadru­pole field er­rors and its im­pact onto hor­i­zon­tal and ver­ti­cal rms emit­tance. Multi-quads scan and two quads with ro­tated slits scan were pro­posed to mea­sure the 4D beam ma­trix for PITZ and tested by sim­u­la­tion, which will give the resid­ual beam cou­pling after gun quadrupoles com­pen­sa­tion and would be help­ful for min­i­miz­ing the 2D rms emit­tance ex­per­i­men­tally.  
poster icon Poster THPO118 [1.521 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO118  
About • paper received ※ 08 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO124 Design of Pulsed HV and RF Combined Gun System Using Gridded Thermionic-Cathode 949
 
  • T. Asaka, H. Tanaka
    RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
  • Y. Otake
    JASRI, Hyogo, Japan
  • T. Taniuchi
    JASRI/SPring-8, Hyogo-ken, Japan
  
  In re­cent state-of -arts ac­cel­er­a­tors like an X-ray free elec­tron laser, the elec­tron beam per­for­mance of a lin­ear ac­cel­er­a­tor de­mands a low emit­tance of ~ 2mm mrad. To ob­tain the low-emit­tance, such a 500kV thermionic-gun at SACLA and a pho­to­cath­ode rf gun gen­er­at­ing 0.5~1MeV elec­tron beams had been de­vel­oped. Al­though the pho­to­cath­ode rf gun is com­pact, it is nec­es­sary to pre­pare a highly sta­bi­lized, large and com­pli­cated laser sys­tem. The 500-kV thermionic-gun of SACLA in­jec­tor has also to pre­pare a tech­ni­cally dif­fi­cult and large high volt­age sys­tem. Hence, we pro­pose a low-emit­tance gun sys­tem with a low-volt­age and grid-loaded 50kV thermionic gun and a 238MHz rf cav­ity to over­come the com­pli­cated dif­fi­culty, as ex­ten­sion of the es­tab­lished tech­nol­ogy. This sys­tem quickly ac­cel­er­ates the elec­tron up to 500keV to pre­serve the low emit­tance and to can­cel a grid fo­cus­ing ef­fect by the space charge force of the beam. By using a par­ti­cle track­ing code, we ob­tained the op­ti­mum volt­age pa­ra­me­ters of the grid and the 238MHz rf for ob­tain­ing the above-men­tioned low emit­tance. In this paper, we pre­sent a nu­mer­i­cal fea­si­bil­ity study to re­al­ize the low-emit­tance gun sys­tem.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO124  
About • paper received ※ 10 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO125 Runing Status of SRF Gun II at the ELBE Radiation Center 952
 
  • R. Xiang, A. Arnold, P.N. Lu, P. Murcek, J.S. Schaber, J. Teichert, H. Vennekate, P.Z. Zwartek
    HZDR, Dresden, Germany
  
  Funding: The work is supported by the German Federal Ministry of Education and Research (BMBF) grant 05K12CR1 and the Deutsche Forschungsgemeinschaft (DFG) grant XI106/2-1.
As a new elec­tron source with higher bril­liance, the sec­ond ver­sion of the su­per­con­duct­ing RF pho­toin­jec­tor (SRF Gun II) has been suc­cess­fully com­mis­sioned at the ELBE Cen­ter for High-Power Ra­di­a­tion Sources since 2014. SRF Gun II fea­tures an im­proved 3.5-cell nio­bium cav­ity as well as a su­per­con­duct­ing so­le­noid in the same cry­omod­ule. For user op­er­a­tion the SRF Gun II with Mg pho­to­cath­ode suc­cess­fully gen­er­ated sta­ble beam with bunch charges up to 200 pC in CW mode, and with sub-ps bunch length. In this pre­sen­ta­tion the gun’s sta­tus and beam pa­ra­me­ters will be pre­sented. 		 
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO125  
About • paper received ※ 12 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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THPO126 Compact H+ ECR Ion Source with Pulse Gas Valve 955
SPWR037   use link to see paper's listing under its alternate paper code  
 
  • Y. Takeuchi, Y. Iwashita, H. Tongu
    Kyoto ICR, Uji, Kyoto, Japan
  
  We are de­vel­op­ing a com­pact ECR H+ ion source with pulse gas valve. In the case of high cur­rent ion linac, the dis­tance be­tween the ion source and the first ac­cel­er­at­ing tube such as RFQ must be as short as pos­si­ble to re­duce the space charge ef­fect, while op­er­at­ing in a high elec­tric field a good vac­uum con­di­tion is de­sir­able. Since hy­dro­gen gas al­ways flows out from ion sources if the plasma cham­ber is filled with the gas, vac­uum pump­ing sys­tems have to evac­u­ate the gas enough be­fore the first ac­cel­er­at­ing tube. The pulse gas in­jec­tion sys­tem achieved by a fast piezo gas valve can re­duce the gas load on the vac­uum evac­u­a­tion sys­tem and is suit­able for in­stalling the ion source close to the RFQ.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO126  
About • paper received ※ 19 September 2018       paper accepted ※ 21 September 2018       issue date ※ 18 January 2019  
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THPO127 The Effect of Energy Fluctuation on the Multi-bunch Acceleration in E-driven ILC Positron Source 958
 
  • M. Kuriki, H. Nagoshi
    HU/AdSM, Higashi-Hiroshima, Japan
  • S. Kashiwagi
    Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
  • K. Negishi
    Iwate University, Morioka, Iwate, Japan
  • T. Okugi, T. Omori, M. Satoh, Y. Seimiya, J. Urakawa, K. Yokoya
    KEK, Ibaraki, Japan
  • Y. Sumitomo
    LEBRA, Funabashi, Japan
  • T. Takahashi
    Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan
  
  E-Dri­ven method is a tech­ni­cal backup for positron source for ILC. In the positron source, the positron is gen­er­ated and ac­cel­er­ated in a multi-bunch for­mat with gaps in a macro-pulse. We em­ploy AM (Am­pli­tude Mod­u­la­tion) to sup­press the tran­sient beam-load­ing, but a small fluc­tu­a­tion is still ex­pected, de­pend­ing on the com­pen­sa­tion ac­cu­racy. In this ar­ti­cle, the positron yield which is ratio of num­bers of positrons over elec­trons, is eval­u­ated as a func­tion of the com­pen­sa­tion ac­cu­racy. With this re­sult and the de­tail in­ves­ti­ga­tion of the beam load­ing com­pen­sa­tion ac­cu­racy by AM, the positron yield of E-Dri­ven Positron source for ILC is eval­u­ated.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO127  
About • paper received ※ 12 September 2018       paper accepted ※ 19 September 2018       issue date ※ 18 January 2019  
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THPO132 Study of the Electron Beam Transfer Line for the AWAKE RUN II Experiment at CERN 962
SPWR036   use link to see paper's listing under its alternate paper code  
 
  • S.Y. Kim, M. Chung
    UNIST, Ulsan, Republic of Korea
  • M. Dayyani
    IPM, Tehran, Iran
  • S. Döbert
    CERN, Geneva, Switzerland
  
  Pro­ton Beam-Dri­ven Plasma Wake­field Ac­cel­er­a­tor (PBD-PWFA) has been ac­tively in­ves­ti­gated at CERN within the AWAKE ex­per­i­ments to study the elec­tron beam ac­cel­er­a­tion using plasma wake fields of the order of GV/m. In the AWAKE RUN 1 ex­per­i­ment an elec­tron beam with an en­ergy of 19 MeV and a bunch length of 2.2 ps rms has been used for the first demon­stra­tion of elec­tron beam ac­cel­er­a­tion in the plasma wake fields. It has been ob­served that the en­ergy gain of the elec­tron beam is up to 2 GeV, and elec­tron cap­ture ef­fi­ciency is few per­cent. Higher cap­tur­ing ef­fi­ciency and emit­tance preser­va­tion could be achieved by mak­ing the elec­tron beam short enough to be in­jected only into the ac­cel­er­a­tion and fo­cus­ing phase of the plasma wake fields. The elec­tron ac­cel­er­a­tor needs to be up­graded for AWAKE RUN 2 ex­per­i­ments to ob­tain a bunch length less than 100 fs which cor­re­sponds to a quar­ter of the plasma wave­length. Planned elec­tron beam pa­ra­me­ters for the AWAKE RUN 2 are a beam charge of 100 pC, and a beam en­ergy larger than 50 MeV. In this paper, we show the elec­tron beam pa­ra­me­ters for RUN 2, and the pa­ra­me­ters of the trans­fer line such as Twiss pa­ra­me­ters, beam en­ve­lope, and emit­tance.
UNIST, Ulsan, 44919, Korea
Institute For Research in Fundamental Sciences, 19395-5531, Tehran, Iran
CERN, Geneva 1211, Switzerland 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO132  
About • paper received ※ 11 September 2018       paper accepted ※ 20 September 2018       issue date ※ 18 January 2019  
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