Author: Dhakal, P.
Paper Title Page
TUPOJO18 Cavity Qualification and Production Update for SNS-PPU Cryomodules at Jefferson Lab 387
 
  • P. Dhakal, E. Daly, J.F. Fischer, N.A. Huque
    JLab, Newport News, Virginia, USA
  • M.P. Howell
    ORNL, Oak Ridge, Tennessee, USA
  • J.D. Mammosser
    ORNL RAD, Oak Ridge, Tennessee, USA
  
  Funding: This manuscript has been authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The Pro­ton Power Up­grade (PPU) pro­ject at Oak Ridge Na­tional Lab’s Spal­la­tion Neu­tron Source (SNS) cur­rently being con­structed will dou­ble the pro­ton beam power ca­pa­bil­ity from 1.4 to 2.8 MW by adding seven cry­omod­ules, each con­tain­ing four six-cell high-beta (β = 0.81) su­per­con­duct­ing radio fre­quency cav­i­ties. Re­search In­stru­ments, lo­cated in Ger­many, built and processed the cav­i­ties at the ven­dor site, in­clud­ing elec­trop­o­l­ish­ing as the final ac­tive chem­istry step. Twenty-eight cav­i­ties for seven cry­omod­ules and an ad­di­tional four cav­i­ties for a spare cry­omod­ules were de­liv­ered to Jef­fer­son Lab and first qual­i­fi­ca­tion tests were com­pleted on all cav­i­ties as re­ceived from the ven­dor. The per­for­mance largely ex­ceeded the re­quire­ments on qual­ity fac­tor and ac­cel­er­at­ing gra­di­ent. Here we pre­sent the sta­tus of ini­tial cav­ity qual­i­fi­ca­tion tests, re­work on un­qual­i­fied cav­i­ties and final cav­ity qual­i­fi­ca­tion with he­lium ves­sel prior to in­stal­la­tion in cry­omod­ules. In ad­di­tion, an up­date on cry­omod­ule pro­duc­tion is pre­sented. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-TUPOJO18  
About • Received ※ 23 August 2022 — Revised ※ 29 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 09 September 2022
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THPOGE16 Evaluation of Single-Cell Cavities Made of Forged Ingot Niobium at Jefferson Lab 828
 
  • P. Dhakal, G. Ciovati, G.R. Myneni
    JLab, Newport News, Virginia, USA
  • G. Ciovati, B.D. Khanal
    ODU, Norfolk, Virginia, USA
  • G.R. Myneni
    BSCE, Yorktown, Virginia, USA
  
  Funding: This manuscript has been authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Cur­rently, fine grain nio­bium (Nb) (grain size ~ 50 um) and large grain Nb (grain size of a few cm) are being used for the fab­ri­ca­tion of su­per­con­duct­ing radio fre­quency (SRF) cav­i­ties. Medium grain forged ingot with grain size of a few hun­dred um may be ben­e­fi­cial for cost-ef­fec­tive­ness as well as pro­vid­ing bet­ter per­for­mance for fu­ture SRF-based ac­cel­er­a­tors. Forged ingot Nb with medium grain size is a novel pro­duc­tion method to ob­tain Nb discs used for the fab­ri­ca­tion of su­per­con­duct­ing radio fre­quency cav­i­ties. We have fab­ri­cated two 1.5 GHz sin­gle cell cav­i­ties made from forged Nb ingot with a resid­ual re­sis­tiv­ity ratio of ~100. The cav­i­ties were chem­i­cally and me­chan­i­cally pol­ished and heat-treated in the tem­per­a­ture range of 650-1000 C be­fore the rf test. One of the cav­i­ties reached an ac­cel­er­at­ing gra­di­ent of 34 MV/m with a qual­ity fac­tor Q > 1e10, while the sec­ond cav­ity was lim­ited at 14 MV/m, likely due to a weld de­fect at the equa­tor. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOGE16  
About • Received ※ 22 August 2022 — Revised ※ 29 August 2022 — Accepted ※ 03 September 2022 — Issue date ※ 15 September 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)