FROXGD —  Contributed Orals: Beam Instrumentation, Controls, Feedback and Op. Aspects   (17-Jun-22   09:30—10:30)
Chair: H. Maesaka, RIKEN SPring-8 Center, Hyogo, Japan
Paper Title Page
FROXGD1 A Method for Obtaining 3D Charge Density Distribution of a Self-Modulated Proton Bunch 3118
 
  • T. Nechaeva, P. Muggli
    MPI-P, München, Germany
  • L. Verra, G. Zevi Della Porta
    CERN, Meyrin, Switzerland
  • L. Verra
    TUM, Munich, Germany
  • L. Verra
    MPI, Muenchen, Germany
  
  The Ad­vanced Wake­field Ex­per­i­ment (AWAKE) at CERN is the first plasma wake­field ac­cel­er­a­tor ex­per­i­ment to use a pro­ton bunch as dri­ver. The long bunch un­der­goes seeded self-mod­u­la­tion (SSM) in a 10 m-long plasma. SSM trans­forms the bunch into a train of short mi­cro-bunches that res­o­nantly drive high-am­pli­tude wake­fields. We use op­ti­cal tran­si­tion ra­di­a­tion (OTR) and a streak cam­era to ob­tain time-re­solved im­ages of the bunch trans­verse charge den­sity dis­tri­b­u­tion in a given plane. In this paper we pre­sent a method to ob­tain 3D im­ages of the bunch by scan­ning the OTR across the en­trance slit of the streak cam­era. Re­con­struc­tion of the 3D dis­tri­b­u­tion is pos­si­ble be­cause with seed­ing self-mod­u­la­tion is re­pro­ducible*. The 3D im­ages allow for check­ing the axi-sym­me­try of SSM and for de­tect­ing the pos­si­ble pres­ence of the non-axi-sym­met­ric hos­ing in­sta­bil­ity (HI).
* F. Batsch et al., Phys. Rev. Lett. 126, 164802 (2021).
 		 
slides icon Slides FROXGD1 [4.026 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-FROXGD1  
About • Received ※ 20 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 30 June 2022
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FROXGD2
 Development of a Quantum Electron Beam Diagnostic Apparatus  
 
  • S. Zhang, A. Camsonne, G.-T. Park
    JLab, Newport News, Virginia, USA
  
  Funding: U.S. DOE Contract No. DE-AC05-06OR23177 and Jefferson Lab LDRD program.
Char­ac­ter­i­za­tion of elec­tron beam prop­er­ties using op­ti­cal de­tec­tion meth­ods through the in­ter­ac­tion be­tween pho­tons and elec­trons such as Comp­ton scat­ter­ing or elec­tro-op­tic sam­pling have been suc­cess­fully im­ple­mented as non-in­va­sive di­ag­nos­tics at var­i­ous ac­cel­er­a­tor fa­cil­i­ties. How­ever, such meth­ods often suf­fer from in­her­ently low sen­si­tiv­ity. Here we pre­sent the study of a new type of elec­tron beam di­ag­nos­tic de­vice for di­rect op­ti­cal imag­ing of elec­tron beams at var­i­ous en­ergy lev­els. The con­cept re­lies on high sen­si­tiv­ity of atoms, pre­pared in a spe­cific spin quan­tum su­per­po­si­tion, to the per­tur­ba­tions in­duced by the pass­ing charged par­ti­cle. Specif­i­cally, the mag­netic field of the elec­trons in­duces po­lar­iza­tion change of the probe light as well as changes in light ab­sorp­tion and flu­o­res­cence, en­abling di­rect 3D imag­ing of the charged par­ti­cles with high res­o­lu­tion. We re­port our re­cent ex­per­i­ment re­sults and the de­sign ef­fort on a com­pact ap­pa­ra­tus in­tended to be tested with the rel­a­tivis­tic elec­tron beams at Jef­fer­son Lab­o­ra­tory. 		 
slides icon Slides FROXGD2 [17.656 MB]  
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FROXGD3 Injection Beam Measurement Using Synchrotron Radiation Monitor at the SuperKEKB Electron Ring 3121
 
  • H. Ikeda, T.M. Mitsuhashi, G. Mitsuka
    KEK, Ibaraki, Japan
  
  We up­graded the di­a­mond mir­ror of the Su­perKEKB elec­tron ring to ex­tract the good qual­ity syn­chro­tron light in 2020 sum­mer. As a re­sult, the ac­cu­racy of pro­file mea­sure­ment for each bunch using a gate cam­era has im­proved dra­mat­i­cally, and it has be­come pos­si­ble to mea­sure the in­ci­dent beam for each turn. The elec­tron beam was in­jected with sin­gle turn in­jec­tion mode to mea­sure the prop­er­ties of the beam and mea­sured turn by turn after in­jec­tion. In order to con­vert the mea­sure­ment re­sults into beam size, con­vo­lu­tion by dif­frac­tion ef­fect and ab­solute value cal­i­bra­tion using real im­ages were per­formed. We re­port the be­hav­ior of the in­jec­tion beam dur­ing nor­mal op­er­a­tion of Su­perKEKB.  
slides icon Slides FROXGD3 [5.560 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-FROXGD3  
About • Received ※ 09 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 07 July 2022
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