Author: Freemire, B.T.
Paper Title Page
MOPAB352 High Power Test of a Dielectric Disk Loaded Accelerator for a Two Beam Wakefield Accelerator 1096
 
  • B.T. Freemire, C.-J. Jing, S. Poddar
    Euclid Beamlabs, Bolingbrook, USA
  • M.E. Conde, D.S. Doran, G. Ha, W. Liu, J.G. Power, J.H. Shao, C. Whiteford, E.E. Wisniewski
    ANL, Lemont, Illinois, USA
  • M.M. Peng
    TUB, Beijing, People’s Republic of China
  • E.E. Wisniewski
    Illinois Institute of Technology, Chicago, Illinois, USA
  • Y. Zhao
    Euclid TechLabs, Solon, Ohio, USA
  
  Funding: Small Business Innovation Research Contract No. DE-SC0019864 U.S. DOE Office of Science Contract No. DE-AC02-06CH11357
As part of the Ar­gonne 500 MeV short pulse Two Beam Wake­field Ac­cel­er­a­tion Demon­stra­tor, a sin­gle cell X-band di­elec­tric disk loaded ac­cel­er­a­tor (DDA) has been de­signed, fab­ri­cated, and tested at high power at the Ar­gonne Wake­field Ac­cel­er­a­tor. The DDA should pro­vide a short pulse (~20 ns) high gra­di­ent (>300 MV/m) ac­cel­er­a­tor while main­tain­ing a rea­son­able r/Q and high group ve­loc­ity. This will allow a sig­nif­i­cantly larger RF-to-beam ef­fi­ciency than is cur­rently pos­si­ble for con­ven­tional ac­cel­er­at­ing struc­tures. A low loss bar­ium ti­tan­tate ce­ramic, µr = 50, was se­lected, and a low tem­per­a­ture braz­ing alloy cho­sen to pre­serve the di­elec­tric prop­er­ties of the ce­ramic dur­ing braz­ing. High power test­ing pro­duced break­down at the triple junc­tion, re­sult­ing from the braze joint de­sign. No ev­i­dence of break­down was ob­served on the iris of the disk, in­di­cat­ing that the max­i­mum sur­face elec­tric field on the di­elec­tric was not reached. An im­proved braze joint has been de­signed and is in pro­duc­tion, with high power test­ing to fol­low. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB352  
About • paper received ※ 19 May 2021       paper accepted ※ 08 June 2021       issue date ※ 21 August 2021  
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MOPAB142 A Compact, Low-Field, Broadband Matching Section for Externally-Powered X-Band Dielectric-Loaded Accelerating Structures 495
 
  • Y. Wei, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • H. Bursali
    Sapienza University of Rome, Rome, Italy
  • N. Catalán Lasheras, S. Gonzalez Anton, A. Grudiev, R. Wegner, Y. Wei
    CERN, Meyrin, Switzerland
  • B.T. Freemire, C.-J. Jing
    Euclid TechLabs, Solon, Ohio, USA
  • J. Sauza-Bedolla
    Lancaster University, Lancaster, United Kingdom
  • Y. Wei, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  It has been tech­ni­cally chal­leng­ing to ef­fi­ciently cou­ple ex­ter­nal ra­diofre­quency (RF) power to cylin­dri­cal di­elec­tric-loaded ac­cel­er­at­ing (DLA) struc­tures. This is es­pe­cially true when the DLA struc­ture has a high di­elec­tric con­stant. This con­tri­bu­tion pre­sents a novel de­sign of a match­ing sec­tion for cou­pling the RF power from a cir­cu­lar wave­guide to an X-band DLA struc­ture with a di­elec­tric con­stant εr=16.66 and a loss tan­gent \tanθ = 3.43× 10-5. It con­sists of a very com­pact di­elec­tric disk with a width of 2.035 mm and a tilt angle of 60 de­grees, re­sult­ing in a broad­band cou­pling at a low RF field which has the po­ten­tial to sur­vive in the high-power en­vi­ron­ment. To pre­vent a sharp di­elec­tric cor­ner break, a 45-de­gree cham­fer is added. More­over, a mi­croscale vac­uum gap, caused by metal­lic clamp­ing be­tween the thin coat­ing and the outer thick cop­per jacket, is stud­ied in de­tail. Based on sim­u­la­tion stud­ies, a pro­to­type of the DLA struc­ture with the match­ing sec­tions was fab­ri­cated. Re­sults from pre­lim­i­nary bench mea­sure­ments and their com­par­i­son with de­sign val­ues will also be dis­cussed.  
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB142  
About • paper received ※ 11 May 2021       paper accepted ※ 21 May 2021       issue date ※ 19 August 2021  
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WEPAB172 Recent Developments of the IDEAS-Halo Detector 3005
 
  • A. Liu, J.R. Callahan, B.T. Freemire
    Euclid TechLabs, Solon, Ohio, USA
  • J.F. Power, J.H. Shao
    ANL, Lemont, Illinois, USA
  
  Funding: This work was performed at Euclid and Argonne National Laboratory, and was supported by the US DOE Office of Science under contract number DE-SC0019538.
Eu­clid Tech­labs has been de­sign­ing and test­ing a cost-ef­fec­tive iris di­aphragm beam halo/pro­file de­tec­tor, which can be eas­ily con­fig­ured to work with var­i­ous pri­mary beam en­er­gies and sites. Be­sides work­ing as a mea­sure­ment de­vice, it can also work as a con­trol­lable beam scraper/col­li­ma­tor. This novel iris di­aphragm de­tec­tor uti­lizes the cur­rent sig­nal pro­duced by the beam charge de­po­si­tion on the move­able con­duc­tive iris blades, to ac­cu­rately mea­sure the beam dis­tri­b­u­tion from the out­lier to the beam core. In this paper, we dis­cuss the re­cent de­vel­op­ments of our iris di­aphragm e-beam ap­pa­ra­tus se­ries (IDEAS)-halo de­tec­tor, in­clud­ing its geom­e­try up­grades and newest beam ex­per­i­ments done at the AWA cath­ode test­bed (ACT) of Ar­gonne Na­tional Lab­o­ra­tory. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB172  
About • paper received ※ 03 June 2021       paper accepted ※ 22 July 2021       issue date ※ 27 August 2021  
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