Evolution of field emitters on copper surface during conditioning

To understand the mechanism of structure conditioning under high-power RF fields, a cathode image beamline based on field emission current was built at Tsinghua University. Cathodes made of oxygen-free copper were conditioned on the beamline. To monitor the modification of the cathode surface during...

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Bibliographic Details
Published in:Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Accelerators, spectrometers, detectors and associated equipment, 2022-10, Vol.1040, p.167200, Article 167200
Main Authors: Zhou, Liuyuan, Zha, Hao, Shi, Jiaru, Qiu, Jiaqi, Wang, Chuanjing, Han, Yunsheng, Fu, Yixiao, Chen, Huaibi
Format: Article
Language:English
Subjects:
Conditioning
Field emission
RF breakdown
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Summary:To understand the mechanism of structure conditioning under high-power RF fields, a cathode image beamline based on field emission current was built at Tsinghua University. Cathodes made of oxygen-free copper were conditioned on the beamline. To monitor the modification of the cathode surface during conditioning, a designed solenoid focused the field emission current from the cathode to a YAG screen 1m away. The experiment showed that strong field emitters spontaneously appeared after breakdowns occurred, and the emitters were eliminated with increasing RF power. These results suggest that the conditioning process converts subsurface defects into field emitters and eliminates the emitters to improve the gradient threshold of breakdown.
ISSN:0168-9002
1872-9576
DOI:10.1016/j.nima.2022.167200