Keyword: simulation
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MO1C3 High Voltage Upgrade of the 14UD Tandem Accelerator electron, heavy-ion, operation, acceleration 1
 
  • T.B. Tunningley, S.T. Battisson, A. Cooper, J.K. Heighway, D.J. Hinde, C. Kafer, T. Kitchen, P. Linardakis, N.R. Lobanov, C. Notthoff, T. Tempra, B. Tranter, R. Tranter
    Research School of Physics and Engineering, Australian National University, Canberra, Australian Capitol Territory, Australia
  • R.A. Bosch
    UW-Madison/SRC, Madison, Wisconsin, USA
  • J.E. Raatz
    NEC, Middleton, Wisconsin, USA
  
  The 14UD at the Aus­tralian Na­tional Uni­ver­sity’s Heavy Ion Ac­cel­er­a­tor Fa­cil­ity (HIAF) op­er­ated at a max­i­mum volt­age of 15.5 MV after the in­stal­la­tion of tubes with a com­pressed geom­e­try in the 1990s. In re­cent years, the per­for­mance of the ac­cel­er­a­tor has shown a grad­ual de­cline to a max­i­mum op­er­a­tion volt­age of ~14.5 MV. There are some fun­da­men­tal fac­tors that limit the high volt­age per­for­mance, such as SF6 gas pres­sure, field en­hance­ment due to triple junc­tions and total volt­age ef­fect. In 2019 ANU ini­ti­ated the fea­si­bil­ity study of avail­able op­tions to up­grade the en­tire pop­u­la­tion of sup­port­ing posts, ac­cel­er­a­tion tubes and grad­ing re­sis­tors. In this paper we will dis­cuss the pre­ferred tech­nolo­gies and strate­gies for suc­cess­ful im­ple­men­ta­tion of this de­vel­op­ment. The cho­sen de­sign is based on NEC tubes with mag­netic elec­tron sup­pres­sion and min­i­mized steer­ing of ion beam. The new grad­ing re­sis­tors mount­ing op­tions and im­proved volt­age dis­tri­b­u­tion along ac­cel­er­a­tor col­umn time­line will be dis­cussed.  
slides icon Slides MO1C3 [28.718 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HIAT2022-MO1C3  
About • Received ※ 25 May 2022 — Revised ※ 27 June 2022 — Accepted ※ 10 August 2022 — Issue date ※ 19 September 2022
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TU1C4 A 3D Printed IH-Type Linac Structure - Proof-of-Concept for Additive Manufacturing of Linac RF Cavities cavity, vacuum, linac, experiment 41
 
  • H. Hähnel, A. Ateş, U. Ratzinger
    IAP, Frankfurt am Main, Germany
  
  Funding: This research was funded by BBMBF grant number 05P21RFRB2.
Ad­di­tive man­u­fac­tur­ing ("AM" or "3D print­ing") has be­come a pow­er­ful tool for rapid pro­to­typ­ing and man­u­fac­tur­ing of com­plex geome­tries. A 433 MHz IH-DTL cav­ity has been con­structed to act as a proof of con­cept for ad­di­tive man­u­fac­tur­ing of linac com­po­nents. In this case, the in­ter­nal drift tube struc­ture has been pro­duced from 1.4404 stain­less steel using 3D print­ing. We pre­sent the con­cept of the cav­ity as well as first re­sults of vac­uum test­ing and ma­te­ri­als test­ing. Vac­uum lev­els suf­fi­cient for linac op­er­a­tion have been reached with the AM linac struc­ture. 		 
slides icon Slides TU1C4 [5.326 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HIAT2022-TU1C4  
About • Received ※ 20 June 2022 — Revised ※ 30 June 2022 — Accepted ※ 10 August 2022 — Issue date ※ 20 September 2022
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TUP04 New Method for Overcoming Dipole Effects of 4-Rod RFQs dipole, rfq, impedance, ECR 72
 
  • S. Wunderlich, C. Zhang
    GSI, Darmstadt, Germany
  
  A new de­sign of a 4-rod RFQ has been de­vel­oped and sim­u­lated. In con­trast to con­ven­tional de­signs, it uses asym­met­ri­cal stem geom­e­try in the ver­ti­cal-lon­gi­tu­di­nal plane. The ef­fect on di­pole fields for dif­fer­ent geo­met­ri­cal pa­ra­me­ters were ex­am­ined and will be dis­cussed.  
poster icon Poster TUP04 [0.300 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HIAT2022-TUP04  
About • Received ※ 21 June 2022 — Revised ※ 19 July 2022 — Accepted ※ 10 August 2022 — Issue date ※ 19 September 2022
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TUP05 Prototype Room Temperature Quadrupole Chamber with Cryogenic Installations cryogenics, quadrupole, vacuum, synchrotron 75
 
  • S. Aumüller, L.H.J. Bozyk, P.J. Spiller
    GSI, Darmstadt, Germany
  • K. Blaum
    MPI-K, Heidelberg, Germany
  
  The syn­chro­tron SIS100 at FAIR ac­cel­er­a­tor com­plex at the GSI Helmholtzzen­trum will gen­er­ate heavy ion beams of ul­ti­mate in­ten­si­ties. As medium charge states have to be used, the prob­a­bil­ity for charge ex­change in col­li­sions with resid­ual gas par­ti­cles of such ions is much lager than for higher charge states. In the last years, sev­eral mea­sures have low­ered the resid­ual gas den­sity to ex­treme high vac­uum con­di­tions. For ex­am­ple 55% of the cir­cum­fer­ence of SIS18 have al­ready been coated with NEG, which pro­vides high and dis­trib­uted pump­ing speed. Nev­er­the­less, this coat­ing does not pump nobel and no­bel-like com­po­nents, which have very high ion­iza­tion cross sec­tions. A cryo­genic en­vi­ron­ment at e.g. 50-80K pro­vides a high pump­ing speed for all heavy resid­ual gas par­ti­cles. The only typ­i­cal resid­ual gas par­ti­cle that can­not be pumped at this tem­per­a­ture is hy­dro­gen. With the pump­ing speed of an ad­di­tional NEG coat­ing in these areas, the pump­ing will be op­ti­mized for all resid­ual gas par­ti­cles. The in­stal­la­tion of cryo­genic in­stal­la­tions in the ex­ist­ing room tem­per­a­ture syn­chro­tron SIS18 at GSI has been in­ves­ti­gated. Mea­sure­ments on a pro­to­type cham­ber and sim­u­la­tions of SIS18 with cryo­genic in­stal­la­tions based on these mea­sure­ments are pre­sented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HIAT2022-TUP05  
About • Received ※ 21 June 2022 — Revised ※ 30 June 2022 — Accepted ※ 01 July 2022 — Issue date ※ 10 August 2022
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TUP06 Cryogenic Surfaces in a Room Temperature SIS18 Ioncatcher vacuum, cryogenics, heavy-ion, operation 79
 
  • L.H.J. Bozyk, S. Aumüller, P.J. Spiller
    GSI, Darmstadt, Germany
  
  For FAIR op­er­a­tion, the ex­ist­ing heavy ion syn­chro­tron SIS18 at GSI will be used as booster for the fu­ture SIS100. In order to reach the in­ten­sity goals, medium charge state heavy ions will be used. Un­for­tu­nately, such ions have very high ion­iza­tion cross sec­tions in col­li­sions with resid­ual gas par­ti­cles, yield­ing in beam loss and a sub­se­quent pres­sure rise via ion im­pact stim­u­lated gas des­orp­tion. To re­duce the des­orp­tion yield, room tem­per­a­ture ion­catcher have been in­stalled, which pro­vide low des­orp­tion sur­faces. Sim­u­la­tions in­clud­ing cryo­genic sur­faces show, that their high stick­ing prob­a­bil­ity pre­vents the vac­uum sys­tem from pres­sure built-ups dur­ing op­er­a­tion. Such, the op­er­a­tion with heavy ion beams can be sta­bi­lized at higher heavy ion in­ten­si­ties, than solely with room tem­per­a­ture sur­faces. A pro­to­type ion­catcher con­tain­ing cryo­genic sur­faces has been de­vel­oped and built. The sur­faces are cooled by a com­mer­cial cold­head, which eas­ily al­lows this sys­tem being in­te­grated into the room tem­per­a­ture syn­chro­tron. The de­vel­op­ment and first lab­o­ra­tory tests in­clud­ing fast pres­sure mea­sure­ments of this sys­tem will be pre­sented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HIAT2022-TUP06  
About • Received ※ 21 June 2022 — Accepted ※ 01 July 2022 — Issue date ※ 10 August 2022  
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TUP08 RF Chopper for Prebunched Radioactive Ion Beams cavity, cryomodule, rfq, dipole 87
 
  • A.J. Gonzalez, A.S. Plastun
    FRIB, East Lansing, Michigan, USA
  
  An RF chop­per sys­tem is being de­signed for the Re-Ac­cel­er­a­tor (ReA) linac at the Fa­cil­ity for Rare Iso­tope Beams (FRIB) at Michi­gan State Uni­ver­sity (MSU). The chop­per sys­tem is de­signed to clean out satel­lite bunches and pro­duce a 16.1 MHz bunch struc­ture, which al­lows for time-of-flight sep­a­ra­tion of the iso­topes. The chop­per sys­tem’s lo­ca­tion in the beam­line is be­tween the ReA3 and ReA6 cry­omod­ules. In ReA, the beam can be pre­bunched at the fre­quency of 16.1 MHz and ac­cel­er­ated in a 80.5 MHz RFQ, pro­duc­ing four satel­lite bunches for every one high-in­ten­sity bunch. The chop­per sys­tem in­cludes an RF de­flec­tor op­er­at­ing at 64.4 MHz, which is the beat fre­quency of 80.5 MHz and 16.1 MHz. The de­flec­tor de­flects every bunch to spa­tially sep­a­rate high-in­ten­sity and satel­lite bunches. The beam tra­jec­tory is bi­ased by a con­stant mag­netic field to en­sure the high-in­ten­sity bunches do not ex­pe­ri­ence any total de­flec­tion. The kicked bunches are low in in­ten­sity and will be sent to a beam dump, re­sult­ing in a clean 16.1 MHz beam struc­ture in­jected into the ReA6 cry­omod­ule.  
poster icon Poster TUP08 [0.437 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HIAT2022-TUP08  
About • Received ※ 20 June 2022 — Revised ※ 30 June 2022 — Accepted ※ 10 August 2022 — Issue date ※ 19 September 2022
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TH1I2 Reinforcement Learning and Bayesian Optimization for Ion Linac Operations controls, quadrupole, rfq, experiment 130
 
  • J.L. Martinez Marin, B.R. Blomberg, K.J. Bunnell, G.M. Dunn, E. Letcher, B. Mustapha, D. Stanton
    ANL, Lemont, Illinois, USA
  
  Funding: This work was supported by the U.S. Department of Energy, under Contract No. DE-AC02-06CH11357. This research used the ATLAS facility, which is a DOE Office of Nuclear Physics User Facility.
The use of ar­ti­fi­cial in­tel­li­gence can sig­nif­i­cantly re­duce the time needed to tune an ac­cel­er­a­tor sys­tem such as the Ar­gonne Tan­dem Lin­ear Ac­cel­er­a­tor Sys­tem (ATLAS) where a new beam is tuned once or twice a week. After es­tab­lish­ing au­to­matic data col­lec­tion pro­ce­dures and hav­ing analysed the data, ma­chine learn­ing mod­els were de­vel­oped and tested to tune sub­sec­tions of the linac. Mod­els based on Re­in­force­ment Learn­ing (RL) and Bayesian Op­ti­miza­tion (BO) were de­vel­oped, their re­spec-tive re­sults are dis­cussed and com­pared. RL and BO are well known AI tech­niques, often used for con­trol sys­tems. The re­sults were ob­tained for a sub­sec­tion of ATLAS that con­tains com­plex el­e­ments such as the ra­dio-fre­quency quadru­pole (RFQ). The mod­els will be later gen­er­al­ized to the whole ATLAS linac, and sim­i­lar mod­els can be de­vel-oped for any ac­cel­er­a­tor with a mod­ern con­trol sys­tem. 		 
slides icon Slides TH1I2 [4.617 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HIAT2022-TH1I2  
About • Received ※ 09 July 2022 — Revised ※ 10 August 2022 — Accepted ※ 19 September 2022 — Issue date ※ 19 September 2022
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TH1C4 Cavity Designs for the CH3 to CH11 and Bellow Tuner Investigation of the Superconducting Heavy Ion Accelerator HELIAC cavity, SRF, heavy-ion, niobium 140
 
  • T. Conrad, H. Podlech, M. Schwarz
    IAP, Frankfurt am Main, Germany
  • K. Aulenbacher, W.A. Barth, F.D. Dziuba, T. Kürzeder, S. Lauber, J. List, M. Miski-Oglu
    HIM, Mainz, Germany
  • K. Aulenbacher
    IKP, Mainz, Germany
  • W.A. Barth, M. Basten, F.D. Dziuba, V. Gettmann, M. Heilmann, T. Kürzeder, S. Lauber, J. List, M. Miski-Oglu, A. Rubin, A. Schnase, S. Yaramyshev
    GSI, Darmstadt, Germany
  
  New CH-DTL cav­i­ties de­signs of the planned Helmholtz Lin­ear Ac­cel­er­a­tor (HE­LIAC) are de­vel­oped in col­lab­o­ra­tion of GSI, HIM and IAP Frank­furt. The in cw-mode op­er­at­ing linac with a final en­ergy of 7.3 MeV/u, is in­tended for var­i­ous ex­per­i­ments, in par­tic­u­lar with heavy ions at en­er­gies close to the Coulomb bar­rier for re­search on SHE. Twelve sc CH cav­i­ties are fore­seen, di­vided into four dif­fer­ent cryostats each equipped with two dy­namic bel­low tuner. After suc­cess­ful beam tests with CH0, CH3 to CH11 were de­signed. Based on the ex­pe­ri­ence gained so far, op­ti­miza­tions were made, which will lead to both an in­crease in per­for­mance in terms of re­duc­ing the peak fields lim­it­ing su­per­con­duc­tiv­ity and a re­duc­tion in man­u­fac­tur­ing costs and time. In order to op­ti­mize man­u­fac­tur­ing, at­ten­tion was paid to de­sign many parts of the cav­ity, such as lids, spokes, tuner and he­lium shell, with the same geo­met­ri­cal di­men­sions. In ad­di­tion, a tuner test rig was de­vel­oped, which will be used to in­ves­ti­gate the me­chan­i­cal prop­er­ties of the bel­low tuner. For this pur­pose, dif­fer­ent sim­u­la­tions were made in order to re­al­ize con­di­tions as close as pos­si­ble to re­al­ity in the test rig.  
slides icon Slides TH1C4 [6.439 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HIAT2022-TH1C4  
About • Received ※ 27 June 2022 — Revised ※ 19 July 2022 — Accepted ※ 10 August 2022 — Issue date ※ 19 September 2022
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