Effect of successive heat treatment on the performance of superconducting radio frequency niobium cavities

Conference · Fri Jul 01 04:00:00 EDT 2022

OSTI ID:1972830

Khanal, Bashu ^[1]; Dhakal, Pashupati ^[2]

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1. Old Dominion Univ., Norfolk, VA (United States)
2. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

One of the primary sources of radio frequency residual losses leading to lower quality factor is trapped residual magnetic field during the cooldown of superconducting radio frequency cavities. It has been reported that non-uniform recrystallization of niobium cavities after the post fabrication heat treatment leads to higher flux trapping during the cooldown, and hence the lower quality factor. Here, we fabricated two 1.3 GHz single cell cavities from high purity fine grain niobium and processed with successive heat treatments in the range 800-1000 ?C to measure the flux expulsion and flux trapping sensitivity. The results show the improved flux expulsion with increase in heat treatment temperature and flux trapping sensitivity depends on the final surface preparation prior to the rf test.

• Research Organization: Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP)
• DOE Contract Number: AC05-06OR23177
• OSTI ID: 1972830
• Report Number(s): JLAB-ACC-22-3733; DOE/OR/23177-5626
• Country of Publication: United States
• Language: English