| Autor: |
Pashupati Dhakal, Santosh Chetri, Shreyas Balachandran, Peter J. Lee, Gianluigi Ciovati |
| Jazyk: |
angličtina |
| Rok vydání: |
2018 |
| Předmět: |
|
| Zdroj: |
Physical Review Accelerators and Beams, Vol 21, Iss 3, p 032001 (2018) |
| Druh dokumentu: |
article |
| ISSN: |
2469-9888 |
| DOI: |
10.1103/PhysRevAccelBeams.21.032001 |
| Popis: |
We report the rf performance of a single cell superconducting radiofrequency cavity after low temperature baking in a nitrogen environment. A significant increase in quality factor has been observed when the cavity was heat treated in the temperature range of 120–160 °C with a nitrogen partial pressure of ∼25 m Torr. This increase in quality factor as well as the Q-rise phenomenon (anti-Q-slope) is similar to those previously obtained with high temperature nitrogen doping as well as titanium doping. In this study, a cavity N_{2}-treated at 120 °C and at 140 °C showed no degradation in accelerating gradient, however the accelerating gradient was reduced by ∼25% with a 160 °C N_{2} treatment, compared to the baseline tests after electropolishing. Sample coupons treated in the same conditions as the cavity were analyzed by scanning electron microscope, x-ray photoelectron spectroscopy and secondary ion mass spectroscopy revealed a complex surface composition of Nb_{2}O_{5}, NbO and NbN_{(1−x)}O_{x} within the rf penetration depth. Furthermore, magnetization measurements showed no significant change on bulk superconducting properties. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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