Surface studies of niobium chemically polished under conditions for superconducting radio frequency (SRF) cavity production

2006 ◽  
Vol 253 (3) ◽  
pp. 1236-1242 ◽  
Author(s):  
Hui Tian ◽  
Charles E. Reece ◽  
Michael J. Kelley ◽  
Shancai Wang ◽  
Lukasz Plucinski ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Surface Studies ◽  
Superconducting Radio Frequency ◽  
Srf Cavity

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.

Development of a 1497-MHz, 13.5-kW Continuous-Wave Magnetron for Superconducting Radio Frequency Accelerator

2021 ◽  
pp. 1-9
Author(s):  
Wenliang Li ◽  
Pengjiao Zhang ◽  
Bowen Zhou ◽  
Hong Zhang ◽  
Youchun Liu ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Continuous Wave ◽  
Superconducting Radio Frequency

scholarly journals Long lifetime of bialkali photocathodes operating in high gradient superconducting radio frequency gun

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
E. Wang ◽  
V. N. Litvinenko ◽  
I. Pinayev ◽  
M. Gaowei ◽  
J. Skaritka ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Electron Beams ◽  
Spot Size ◽  
Laser Spot ◽  
Laser Spot Size ◽  
High Quantum Efficiency ◽  
High Brightness ◽  
High Charge ◽  
Superconducting Radio Frequency ◽  
Long Lifetime

AbstractHigh brightness, high charge electron beams are critical for a number of advanced accelerator applications. The initial emittance of the electron beam, which is determined by the mean transverse energy (MTE) and laser spot size, is one of the most important parameters determining the beam quality. The bialkali photocathodes illuminated by a visible laser have the advantages of high quantum efficiency (QE) and low MTE. Furthermore, Superconducting Radio Frequency (SRF) guns can operate in the continuous wave (CW) mode at high accelerating gradients, e.g. with significant reduction of the laser spot size at the photocathode. Combining the bialkali photocathode with the SRF gun enables generation of high charge, high brightness, and possibly high average current electron beams. However, integrating the high QE semiconductor photocathode into the SRF guns has been challenging. In this article, we report on the development of bialkali photocathodes for successful operation in the SRF gun with months-long lifetime while delivering CW beams with nano-coulomb charge per bunch. This achievement opens a new era for high charge, high brightness CW electron beams.

Superconducting Resonators: Decrease of Q-Factor at High Accelerating Field

2014 ◽  
Vol 9 (2) ◽  
pp. 22-35
Author(s):  
Aleksandr Dzyuba ◽  
Andrey Arzhannikov
Keyword(s):  
Radio Frequency ◽  
Research Methods ◽  
Q Factor ◽  
Chemical Research ◽  
Superconducting Resonators ◽  
Alternative Processing ◽  
Physico Chemical ◽  
Superconducting Radio Frequency ◽  
Processing Steps

Results combining efforts of different groups on investigation of losses in superconducting radio frequency cavities made of niobium are presented. Peculiarities of such losses and of their remedies are considered for dissipation at high accelerating voltages. The main results of RF tests as well as main experiments conducted via physico-chemical research methods on samples are discussed. The role of different type of defects on losses is presented. The candidate mechanisms for dissipation are considered based on exhibited results. As a conclusion the prediction is made on possible alternative processing steps for improvement of cost, time and safety efficiency of current technological procedures

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