Superconducting Radio-Frequency Fundamentals for Particle Accelerators

2012 ◽  
Vol 05 ◽  
pp. 119-146 ◽  
Author(s):  
Alex Gurevich
Keyword(s):  
Radio Frequency ◽  
Quality Factor ◽  
Electromagnetic Fields ◽  
Surface Resistance ◽  
Particle Accelerators ◽  
Superconducting Radio Frequency ◽  
Srf Cavities

An overview of fundamentals of superconductors under radio-frequency electromagnetic fields in particle accelerators is given, with emphasis on intrinsic physics and materials mechanisms which limit the performance of the superconducting radio-frequency (SRF) resonator cavities. Multiscale mechanisms which control the surface resistance and the quality factor of the SRF cavities at low and high rf fields are discussed. We also discuss possible ways of pushing the limit of the SRF performance by materials impurities and multilayer nanostructuring which may open up opportunities of using materials other than Nb to significantly increase the maximum accelerating fields and improve the performance of the SRF cavities operating at 4.2 K.

scholarly journals Quality Factor Enhancement of 650 MHz Superconducting Radio-Frequency Cavity for CEPC

2022 ◽  
Vol 12 (2) ◽  
pp. 546
Author(s):  
Peng Sha ◽  
Weimin Pan ◽  
Jiyuan Zhai ◽  
Zhenghui Mi ◽  
Song Jin ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Quality Factor ◽  
Microwave Surface Resistance ◽  
Medium Temperature ◽  
Residual Resistance ◽  
Electron Positron ◽  
Superconducting Radio Frequency ◽  
Unloaded Quality Factor ◽  
Srf Cavity ◽  
Vertical Test

Medium-temperature (mid-T) furnace baking was conducted at 650 MHz superconducting radio-frequency (SRF) cavity for circular electron positron collider (CEPC), which enhanced the cavity unloaded quality factor (Q0) significantly. In the vertical test (2.0 K), Q0 of 650 MHz cavity reached 6.4 × 1010 at 30 MV/m, which is remarkably high at this unexplored frequency. Additionally, the cavity quenched at 31.2 MV/m finally. There was no anti-Q-slope behavior after mid-T furnace baking, which is characteristic of 1.3 GHz cavities. The microwave surface resistance (RS) was also studied, which indicated both very low Bardeen–Cooper–Schrieffer (BCS) and residual resistance. The recipe of cavity process in this paper is simplified and easy to duplicate, which may benefit the SRF community.

Superconducting Radio-Frequency Systems for High-β Particle Accelerators

2012 ◽  
Vol 05 ◽  
pp. 147-184 ◽  
Author(s):  
Sergey Belomestnykh
Keyword(s):  
Radio Frequency ◽  
Recent Progress ◽  
Higher Order ◽  
Particle Accelerators ◽  
Order Mode ◽  
Rf Systems ◽  
Superconducting Radio Frequency ◽  
Photoemission Electron ◽  
Higher Order Mode ◽  
Radio Frequency Systems

This article addresses the physics and engineering of the superconducting radio-frequency systems for high-β particle accelerators. I consider different geometries for cavities, discuss criteria for optimization, and options for higher-order mode damping. In reviewing recent progress in the field, SRF systems are classified according to the functions they perform. These systems are fundamental RF accelerating systems, deflecting/crab cavities, harmonic RF systems, and SRF photoemission electron guns.

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