Keyword: timing
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TUPOST025 Beam Commissioning of the New Digital Low-Level RF System for CERN’s AD LLRF, MMI, operation, proton 911
 
  • M.E. Angoletta, S.C.P. Albright, D. Barrientos, A. Findlay, M. Jaussi, A. Rey, M. Sumiński
    CERN, Meyrin, Switzerland
 
  CERN’s An­tipro­ton De­cel­er­a­tor (AD) has been re-fur­bished to pro­vide re­li­able op­er­a­tion for the Extra Low EN­ergy An­tipro­ton ring (ELENA). In par­tic­u­lar, AD was equipped with a new dig­i­tal Low-Level RF (LLRF) sys­tem that was suc­cess­fully com­mis­sioned dur­ing the sum­mer 2021. The new AD LLRF sys­tem has rou­tinely cap­tured and de­cel­er­ated more than 3·107 an­tipro­tons from 3.5 GeV/c to 100 MeV/c in suc­ces­sive steps, re­ferred to as RF seg­ments, in­ter­leaved by cool­ing pe­ri­ods. The LLRF sys­tem im­ple­ments the fre­quency pro­gram from Btrain data re­ceived over op­ti­cal fiber. Beam phase/ra­dial and cav­ity am­pli­tude/phase feed­back loops are op­er­ated dur­ing each RF seg­ment. An ex­trac­tion syn­chro­niza­tion loop is trig­gered on the ex­trac­tion RF seg­ment to trans­fer a sin­gle bunch of an­tipro­tons to ELENA. Ex­ten­sive di­ag­nos­tics fea­tures are avail­able and op­er­a­tional modes such as bunched beam cool­ing and bunch ro­ta­tion have been suc­cess­fully de­ployed. The LLRF pa­ra­me­ters can be dif­fer­ent for each RF seg­ment and are con­trolled by a ded­i­cated ap­pli­ca­tion. This paper gives an overview of the AD LLRF beam com­mis­sion­ing re­sults ob­tained and chal­lenges over­come. Hints on fu­ture steps are also pro­vided.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST025  
About • Received ※ 25 May 2022 — Accepted ※ 15 June 2022 — Issue date ※ 17 June 2022  
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TUPOST056 Multi-Objective Bayesian Optimization at SLAC MeV-UED electron, gun, controls, detector 995
 
  • F. Ji, A.L. Edelen, R.J. England, P.L. Kramer, D. Luo, C.E. Mayes, M.P. Minitti, S.A. Miskovich, M. Mo, A.H. Reid, R.J. Roussel, X. Shen, X.J. Wang, S.P. Weathersby
    SLAC, Menlo Park, California, USA
 
  SLAC MeV-UED, part of the LCLS user fa­cil­ity, is a pow­er­ful ’elec­tron cam­era’ for the study of ul­tra­fast mol­e­c­u­lar struc­tural dy­nam­ics and the cou­pling of elec­tronic and atomic mo­tions in a va­ri­ety of ma­te­r­ial and chem­i­cal sys­tems. The grow­ing de­mand of sci­en­tific ap­pli­ca­tions calls for rapid switch­ing be­tween dif­fer­ent beam­line con­fig­u­ra­tions for de­liv­er­ing elec­tron beams meet­ing spe­cific user run re­quire­ments, ne­ces­si­tat­ing fast on­line tun­ing strate­gies to re­duce set up time. Here, we uti­lize multi-ob­jec­tive Bayesian op­ti­miza­tion(MOBO) for fast search­ing the pa­ra­me­ter space ef­fi­ciently in a se­ri­al­ized man­ner, and map­ping out the Pareto Front which gives the trade-offs be­tween key beam pa­ra­me­ters, i.e., spot size, q-res­o­lu­tion, pulse length, pulse charge, etc. Al­go­rithm, model de­ploy­ment and first test re­sults will be pre­sented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST056  
About • Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 09 July 2022
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TUPOPT036 Two and Multiple Bunches with the LCLS Copper Linac laser, controls, undulator, electron 1089
 
  • F.-J. Decker, W.S. Colocho, A. Halavanau, A.A. Lutman, J.P. MacArthur, G. Marcus, R.A. Margraf, J.C. Sheppard, J.J. Turner, S. Vetter
    SLAC, Menlo Park, California, USA
 
  Two, four, and even eight bunches were ac­cel­er­ated through the cop­per linac. Two and four bunches were de­liv­ered suc­cess­fully to pho­ton ex­per­i­ments in both the hard (HXR) and soft (SXR) LCLS x-ray lines. In this paper we will con­cen­trate on the more chal­leng­ing is­sues, such as: the BPM de­con­vo­lu­tion for both bunches, RF kicks at longer sep­a­ra­tions, tun­ing chal­lenges, bridg­ing the com­mu­ni­ca­tions gap be­tween the pho­ton and elec­tron side, the lower bunch charges for the eight bunch case, and rapid tim­ing scans over sev­eral ns. We will de­scribe some of the de­vel­oped so­lu­tions and plans for the rest.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT036  
About • Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 28 June 2022
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TUPOPT064 Online Optimization of NSLS-II Dynamic Aperture and Injection Transient injection, kicker, sextupole, lattice 1159
 
  • X. Yang, B. Bacha, S. Buda, C. Danneil, A.A. Derbenev, D.J. Durfee, K. Ha, Y. Hidaka, Y. Hu, Y. Li, D. Padrazo Jr, F. Plassard, T.V. Shaftan, V.V. Smaluk, Y. Tian, G.M. Wang, L.H. Yu
    BNL, Upton, New York, USA
 
  The goal of the NSLS-II on­line op­ti­miza­tion pro­ject is to im­prove the beam qual­ity for the user ex­per­i­ments. To in­crease the beam life­time and in­jec­tion ef­fi­ciency, we have de­vel­oped a model-in­de­pen­dent on­line op­ti­miza­tion of non­lin­ear beam dy­nam­ics using ad­vanced al­go­rithms, such as Ro­bust Con­ju­gate-Gra­di­ent Al­go­rithm (RCDS). The op­ti­miza­tion ob­jec­tive is the in­jec­tion ef­fi­ciency and op­ti­miza­tion vari­ables are the sex­tu­pole mag­net strengths. Using the on­line op­ti­miza­tion tech­nique, we in­creased the NSLS-II dy­namic aper­ture and re­duced the am­pli­tude-de­pen­dent tune shift. Re­cently, the sex­tu­pole op­ti­miza­tion was suc­cess­fully ap­plied to dou­ble the in­jec­tion ef­fi­ciency up to above 90% for the high-chro­matic­ity lat­tice being de­vel­oped to im­prove the beam sta­bil­ity and to in-crease the sin­gle-bunch beam in­ten­sity. Min­i­miz­ing the beam per­tur­ba­tion dur­ing in­jec­tion is the sec­ond ob­jec­tive in this pro­ject, re­al­ized by on­line op­ti­miza­tion of the in­jec­tion kick­ers. To op­ti­mize the full set of kicker pa­ra­me­ters, in­clud­ing the trig­ger tim­ing, am­pli­tude, and pulse width, we up­graded all kicker power sup­plies with the ca­pa­bil­ity of tun­able wave­form width. As a re­sult, we have re­duced the in­jec­tion tran­sient by a fac­tor of 29, down to the limit of 60 um.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT064  
About • Received ※ 18 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 16 June 2022
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TUPOPT066 KEK LUCX Facility Laser-to-RF&RF-to-RF Stability Study and Optimization laser, feedback, LLRF, gun 1167
 
  • K. Popov
    Sokendai, Ibaraki, Japan
  • A. Aryshev, N. Terunuma, J. Urakawa
    KEK, Ibaraki, Japan
 
  KEK LUCX fa­cil­ity* is a lin­ear ac­cel­er­a­tor de­voted to the beam in­stru­men­ta­tion R&Ds for pre­sent and fu­ture ac­cel­er­a­tor sys­tems and col­lid­ers in­clud­ing ILC. Ac­cord­ing to the ILC TDR**, it is nec­es­sary to achieve RF-gun Laser-to-RF&RF-to-RF phase sta­bil­ity of 0.35°(RMS) and am­pli­tude sta­bil­ity of 0.07%(RMS) with im­ple­men­ta­tion of the Dig­i­tal LLRF feed­back based on com­mer­cially avail­able FPGA board and dig­i­tal trig­ger sys­tem. As the first step to achieve ILC sta­bil­ity level at KEK-LUCX fa­cil­ity, pre­sent Laser-to-RF&RF-to-RF phase and am­pli­tude jit­ters were mea­sured using time- and fre­quency-do­main tech­niques. After that, jit­ter in­flu­ence on beam pa­ra­me­ters after RF-gun and main so­le­noid mag­net was sim­u­lated with ASTRA track­ing code*** and re­sults were cross-checked dur­ing LUCX fa­cil­ity beam op­er­a­tion. Fi­nally, sta­ble dig­i­tal trig­ger sys­tem and dig­i­tal LLRF feed­back based on SINAP EVG&EVR and Red­Pi­taya SIG­NAL­lab-250 mod­ules were im­ple­mented. This re­port demon­strates the re­sults of Laser-to-RF&RF-to-RF phase and am­pli­tude jit­ter mea­sure­ments cross-checked with ASTRA sim­u­la­tion and real beam pa­ra­me­ters mea­sure­ments be­fore and after LUCX fa­cil­ity sta­bi­liza­tion.
References
*A. Aryshev et al., Appl. Phys. Lett. 111, 033508 (2017).
**International Linear Collider Reference Design Report, ILC-REPORT-2007-001, 2007.
***https://www.desy.de/~mpyflo/
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT066  
About • Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 03 July 2022
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TUPOPT067 Development of a Trigger Distribution System Based on MicroTCA.4 electron, FPGA, controls, electronics 1171
 
  • H. Maesaka, N. Hosoda, T. Inagaki, E. Iwai, T. Ohshima
    RIKEN SPring-8 Center, Hyogo, Japan
  • N. Hosoda, T. Inagaki, E. Iwai, H. Maesaka, T. Ohshima
    JASRI, Hyogo, Japan
 
  We de­vel­oped a Mi­croTCA.4 (MTCA.4) mod­ule to gen­er­ate and dis­trib­ute trig­ger tim­ing sig­nals. This mod­ule has 16 LVDS in­puts and 16 LVDS out­puts each on the front panel and the Zone 3 con­nec­tor, and 8 M-LVDS I/O’s for MTCA.4 back­plane. The trig­ger tim­ing of each out­put can be pre­cisely ad­justed with the in­ter­val of 238 MHz or 509 MHz clocks by a 24-bit counter. The tim­ing can also be fine-tuned by ~80 ps tap delay. This mod­ule has ad­di­tional 5 op­ti­cal trans­ceivers, one for re­ceiv­ing trig­ger sig­nals from up­stream and four for fanouts to down­stream. A mas­ter mod­ule dis­trib­utes trig­ger sig­nals, trig­ger counts, and event data through op­ti­cal links. Slave mod­ules gen­er­ate trig­ger out­put sig­nals with ap­pro­pri­ate de­lays based on the event data and the local set­ting for each out­put chan­nel. The tim­ing jit­ter was mea­sured to be 40 ps std, which is sig­nif­i­cantly smaller than the clock pe­riod of 238 MHz or 509 MHz. This sys­tem can also dis­trib­ute an alarm sig­nal re­ceived by a slave mod­ule to take data at a faulty sit­u­a­tion. Trig­ger sys­tems with this mod­ule have been uti­lized in SPring-8, SACLA, and New­SUB­ARU and sta­bly syn­chro­nize var­i­ous ac­cel­er­a­tor com­po­nents with suf­fi­cient tim­ing ac­cu­racy.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT067  
About • Received ※ 08 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 20 June 2022  
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THIYGD1 White Rabbit Based Beam-Synchronous Timing Systems for SHINE network, FEL, electron, FPGA 2415
 
  • Y.B. Yan, G.H. Chen, Q.W. Xiao, P.X. Yu
    SSRF, Shanghai, People’s Republic of China
  • G.H. Gong
    Tsinghua University, Beijing, People’s Republic of China
  • J.L. Gu, Z.Y. Jiang, L. Zhao
    USTC, Hefei, Anhui, People’s Republic of China
  • Y.M. Ye
    TUB, Beijing, People’s Republic of China
 
  Shang­hai HIgh rep­e­ti­tion rate XFEL aNd Ex­treme light fa­cil­ity (SHINE) is under con­struc­tion. SHINE re­quires pre­cise dis­tri­b­u­tion and syn­chro­niza­tion of the 1.003086 MHz tim­ing sig­nals over a long dis­tance of about 3.1 km. Two pro­to­type sys­tems were de­vel­oped, both con­tain­ing three func­tions: beam-syn­chro­nous trig­ger sig­nal dis­tri­b­u­tion, ran­dom-event trig­ger sig­nal dis­tri­b­u­tion and data ex­change be­tween nodes. The fre­quency of the beam-syn­chro­nous trig­ger sig­nal can be di­vided ac­cord­ing to the ac­cel­er­a­tor op­er­a­tion mode. Each out­put pulse can be con­fig­ured for dif­fer­ent fill modes. A pro­to­type sys­tem was de­signed based on a cus­tomized clock fre­quency point (64.197530 MHz). An­other pro­to­type sys­tem was de­signed based on the stan­dard White Rab­bit pro­to­col. The DDS (Di­rect Dig­i­tal Syn­the­sis) and D flip-flops (DFFs) are adopted for RF sig­nal trans­fer and pulse con­fig­u­ra­tion. The de­tails of the tim­ing sys­tem de­sign, lab­o­ra­tory test re­sults will be re­ported in this paper.  
slides icon Slides THIYGD1 [5.582 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THIYGD1  
About • Received ※ 29 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 17 June 2022
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THPOST013 Development of a Detection System for Quasi-Monochromatic THz Pulse by a Spatially Modulated Electron Beam electron, laser, radiation, cathode 2469
 
  • K. Murakoshi, Y. Koshiba, Y. Tadenuma, P. Wang, M. Washio
    Waseda University, Tokyo, Japan
  • R. Kuroda
    AIST, Tsukuba, Japan
  • K. Sakaue
    The University of Tokyo, Graduate School of Engineering, Bunkyo, Japan
 
  We have stud­ied the gen­er­a­tion of the broad­band THz pulse using a com­pact lin­ear ac­cel­er­a­tor. The THz pulse is gen­er­ated by con­trol of an elec­tron beam angle to Cherenkov ra­di­a­tion angle. In ad­di­tion, we have suc­ceeded in pro­duc­ing a quasi-mono­chro­matic THz pulse by the spa­tially mod­u­lated elec­tron beam by pass­ing through a slit. This work aims to de­velop a de­tec­tion sys­tem to elu­ci­date the spec­trum of the quasi-mono­chro­matic THz pulse. To de­tect it sta­bly in a noisy ra­di­a­tion en­vi­ron­ment, the sta­bil­ity of probe laser sys­tem for Elec­tro Optic sam­pling and tim­ing syn­chro­niza­tion sys­tem are im­por­tant. In this con­fer­ence, the gen­er­a­tion method of each THz pulses, the re­sults of de­vel­op­ment of de­tec­tion sys­tem, and fu­ture prospect will be re­ported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST013  
About • Received ※ 07 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 24 June 2022
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