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Title: INVESTIGATION OF FREQUENCY BEHAVIOR NEAR TC OF NIOBIUM SUPERCONUDCTING RADIO-FREQUENCYCAVITIES
This paper will present a systematic investigation of the resonant frequency behavior of niobium SRF cavities subject to different surface processing (nitrogen doping, nitrogen infusion, 120°C bake, EP, etc.) near the critical transition temperature. We find features occurring in frequency versus temperature (FvsT) data near Tc that seem to vary with surface processing. Emphasis is placed on one of the observed features: a dip in the superconducting resonant frequency below the normal conducting value which is prominent in nitrogen doped cavities and appears to be a signature of nitrogen doping. This gives further insights on the mechanisms responsible for the large increase in performance of cavities subject to this surface treatment. The magnitude of this dip in frequency is studied and related to possible physical parameters such as the concentration of impurities near the surface and the design resonant frequency of the cavity. A possible explanation for the meaning of this dip is discussed, namely, that it is a result of strong coupling between electrons and phonons within the resonator.  more » « less
Award ID(s):
1734332
PAR ID:
10337562
Author(s) / Creator(s):
Editor(s):
Peter Michel ; André Arnold ; Volker RW Schaa 
Date Published:
Journal Name:
International Conference on RF Superconductivity (19th)
Page Range / eLocation ID:
112-117
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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