Author: Wei, Y.
Paper Title Page
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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MOPAB143 Simulations for MeV Energy Gain in Multi-Micron Vacuum Channel Dielectric Structures Driven by a CO2 Laser 499
 
  • G. Yadav, O. Apsimon, Y. Wei, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • O. Apsimon, C.P. Welsch, G.X. Xia
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • G.X. Xia
    The University of Manchester, Manchester, United Kingdom
 
  Funding: This work was supported by STFC LIV. DAT under grant agreement ST/P006752/1. This research used the resources of the Supercomputing Laboratory at KAUST in Thuwal, Saudi Arabia.
Di­elec­tric Laser Ac­cel­er­a­tors (DLAs) have been demon­strated as a novel scheme for pro­duc­ing high ac­cel­er­a­tion gra­di­ents (~1 GV/m) within the dam­age thresh­old of the di­elec­tric. The com­pact­ness of the DLAs and the low emit­tance of the out­put elec­tron beam make it an at­trac­tive can­di­date for fu­ture en­do­scopic de­vices to be used in tumor ir­ra­di­a­tion. How­ever, due to the small ac­cel­er­at­ing dis­tances(sub-mm), the total en­ergy gain is lim­ited to sub-MeV which re­mains an ob­sta­cle for its re­al­is­tic ap­pli­ca­tions. Also, these DLAs op­er­ate under solid-state lasers with wave­lengths near IR (800 nm to 2 um), where re­quired sub-mi­cron vac­uum chan­nel at such wave­lengths im­poses major aper­ture re­stric­tions for the amount of charge to be ac­cel­er­ated. Here, we pre­sent nu­mer­i­cal sim­u­la­tion re­sults for a di­elec­tric struc­ture ex­cited by a CO2 laser with a wave­length of 10.6 um. Upon in­ject­ing a 50 MeV elec­tron bunch through a 5.3 um di­am­e­ter of vac­uum chan­nel width, our sim­u­la­tion sug­gests an en­ergy gain be­yond 1 MeV. These re­sults are the ini­tial steps for the re­al­iza­tion of an mm-scale DLA ca­pa­ble of pro­duc­ing MeV en­ergy elec­tron beams.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB143  
About • paper received ※ 18 May 2021       paper accepted ※ 02 June 2021       issue date ※ 11 August 2021  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)