MAGNETIC FLUX EXPULSION IN SUPERCONDUCTING RADIO-FREQUENCY NIOBIUM CAVITIES MADE FROM COLD WORKED NIOBIUM
- Old Dominion Univ., Norfolk, VA (United States)
- NHMFL, Tallahassee, Florida, USA
- ASC, Tallahassee, Florida, USA
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
Trapped residual magnetic field during the cool down of superconducting radio frequency (SRF) cavities is one of the primary sources of RF residual losses leading to lower quality factor. Historically, SRF cavities have been fabricated from high purity fine grain niobium with grain size ~50 to 100 µm as well as large grain with grain size of the order of few centimeters. Non-uniform recrystallization of fine-grain Nb cavities after the post fabrication heat treatment leads to higher flux trapping during the cool down, and hence the lower quality factor. We fabricated two 1.3 GHz single cell cavities from cold-worked niobium from different vendors and processed along with cavities made from SRF grade Nb. The flux expulsion and flux trapping sensitivity were measured after successive heat treatments in the range 800 to 1000°C. The flux expulsion from cold-worked fine-grain Nb cavities improves after 800°C/3h heat treatments and it becomes similar to that of standard fine-grain Nb cavities when the heat treatment temperature is higher than 900°C.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Nuclear Physics (NP)
- DOE Contract Number:
- AC05-06OR23177; SC0009960
- OSTI ID:
- 1907405
- Report Number(s):
- JLAB-ACC-22-3683; DOE/OR/23177-5560
- Resource Relation:
- Conference: NAPAC 2022, Albuquerque, NM, USA, 07-12 August 2022
- Country of Publication:
- United States
- Language:
- English
Similar Records
Development of High-efficiency and Cost-effective Forged Ingot Niobium Technology for Science Frontiers and Accelerator Applications
EVALUATION OF FLUX EXPULSION AND FLUX TRAPPING SENSITIVITY OF SRF CAVITIES FABRICATED FROM COLDWORK NB SHEET WITH SUCCESSIVE HEAT TREATMENT