Author: Peacock, R.C.
Paper Title Page
TUPOPA06 Microscopy Investigation on Different Materials After Pulsed High Field Conditioning and Low Energy H-Irradiation 422
SUPCJO06   use link to see paper's listing under its alternate paper code  
 
  • C.F. Da Palma Serafim, G. Bellodi, S. Calatroni, A. Grudiev, A.M. Lombardi, R.C. Peacock, A.T. Perez Fontenla, S. Ramberger, E. Sargsyan, S. Sgobba, W. Wuensch
    CERN, Meyrin, Switzerland
  • F. Djurabekova
    HIP, University of Helsinki, Finland
  
  Dur­ing op­er­a­tion the LINAC4 RFQ (Ra­dio-Fre­quency-Quadru­pole) is ex­posed to high elec­tric fields which can lead to vac­uum break­down. It is also sub­ject to beam loss that can cause sur­face mod­i­fi­ca­tion, in­clud­ing blis­ter­ing, which can re­sult in re­duced elec­tric field han­dling and an in­creased break­down rate. An ex­per­i­men­tal study has been made to iden­tify ma­te­ri­als with high elec­tric field ca­pa­bil­ity and ro­bust­ness to low-en­ergy ir­ra­di­a­tion. In this paper we briefly dis­cuss the se­lec­tion cri­te­ria and we an­a­lyze these ma­te­ri­als in­ves­ti­gat­ing their met­al­lur­gi­cal prop­er­ties using ad­vanced mi­cro­scopic tech­niques such as Scan­ning Elec­tron Mi­cro­scope, Elec­tron Back Scat­tered Dif­frac­tion, En­ergy-dis­per­sive X-ray Spec­troscopy and con­ven­tional op­ti­cal mi­croscopy. These allow to ob­serve and char­ac­ter­ize the dif­fer­ent ma­te­ri­als on aμand a nano-scale, al­low­ing us to com­pare re­sults be­fore and after ir­ra­di­a­tion and break­down test­ing.  
poster icon Poster TUPOPA06 [2.771 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOPA06  
About • Received ※ 14 August 2022 — Revised ※ 23 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 31 August 2022
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TUPOPA13 Pulsed DC High Field Measurements of Irradiated and Non-Irradiated Electrodes of Different Materials 441
SUPCJO07   use link to see paper's listing under its alternate paper code  
 
  • R.C. Peacock, G. Burt
    Lancaster University, Lancaster, United Kingdom
  • G. Bellodi, S. Calatroni, C.F. Da Palma Serafim, A. Grudiev, A.M. Lombardi, A.T. Perez Fontenla, S. Ramberger, E. Sargsyan, S. Sgobba, W. Wuensch
    CERN, Meyrin, Switzerland
  
  Beam loss oc­curs in Radio Fre­quency Quadrupoles (RFQ), and has been ob­served in the H− lin­ear ac­cel­er­a­tor Linac4 (L4) at CERN. To de­ter­mine if beam loss can in­duce break­downs, and to com­pare the ro­bust­ness of dif­fer­ent ma­te­ri­als, tests have been done using pulsed high-volt­age DC sys­tems. Elec­tri­cal break­down phe­nom­ena and con­di­tion­ing processes have been stud­ied using these sys­tems. Cath­odes of dif­fer­ent ma­te­ri­als were ir­ra­di­ated with 1.2x1019 H− p/cm2, the es­ti­mated beam loss of the L4 RFQ over 10 days. The ir­ra­di­ated elec­trodes were in­stalled in a sys­tem to ob­serve if the ir­ra­di­ated area co­in­cided with the break­down lo­ca­tions, with puls­ing pa­ra­me­ters sim­i­lar to the RFQ. Tests of ir­ra­di­ated and non-ir­ra­di­ated elec­trodes of the same ma­te­r­ial were done for com­par­i­son. The main dif­fer­ence ob­served was an in­crease in the num­ber of break­downs dur­ing the ini­tial con­di­tion­ing that re­turned to non-ir­ra­di­ated sam­ple val­ues with fur­ther run­ning. Vi­sual ob­ser­va­tions after ir­ra­di­a­tion show the beam cen­tre and a halo the same di­am­e­ter of the beam pipe. Break­down clus­ters occur in the cen­tre and halo re­gions, sug­gest­ing ir­ra­di­a­tion is not the only fac­tor de­ter­min­ing the break­down prob­a­bil­ity.  
poster icon Poster TUPOPA13 [3.845 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOPA13  
About • Received ※ 23 August 2022 — Revised ※ 29 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 07 September 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)