Picosecond pulsed 532 nm laser system for roughening and secondary electron yield reduction of inner surfaces of up to 15 m long tubes.
Picosecond pulsed 532 nm laser system for roughening and secondary electron yield reduction of inner surfaces of up to 15 m long tubes.
复制标题
DOI：
10.1063/5.0166156
复制
发表时间：
2023-10
期刊：
影响因子：
--
通讯作者：
E. Bez;M. Himmerlich;Benoit Beaudou;A. K. Reascos Portilla;S. Wackerow;M. Rimoldi;Stephan Pfeiffer;Markus Wiesendanger;F. Benabid;M. Taborelli;Amin Abdolvand;P. Chiggiato
中科院分区：
文献类型：
--
作者：
E. Bez;M. Himmerlich;Benoit Beaudou;A. K. Reascos Portilla;S. Wackerow;M. Rimoldi;Stephan Pfeiffer;Markus Wiesendanger;F. Benabid;M. Taborelli;Amin Abdolvand;P. Chiggiato
激光诱导表面结构化是抑制粒子加速器真空管中电子多碰撞的一种有效方法。电子在粗糙的表面结构内散射，导致材料的二次电子产率（SEY）低。然而，具有大纵横比的内部管道表面的激光加工在激光束引导和聚焦方面具有技术挑战性。本文介绍了一台用于大型强子对撞机（LHC）15 m长束流真空管内件加工的532 nm超短脉冲激光装置。皮秒脉冲在200千赫的重复率被引导通过光纤向尺蠖机器人内的光束管行进。该系统已安装、表征并测试了可靠性。第一次表面处理达到了所需的扫描精度。在高平均激光功率（5 W）和低扫描速度（5 mm s-1）的氮气流中进行处理时，观察到以Cu 2 O为主的纳米特征，并且铜的最大SEY从2.1降低到0.7。
Laser-induced surface structuring is a promising method to suppress electron mulitpacting in the vacuum pipes of particle accelerators. Electrons are scattered inside the rough surface structure, resulting in a low Secondary Electron Yield (SEY) of the material. However, laser processing of internal pipe surfaces with a large aspect ratio is technologically challenging in terms of laser beam guidance and focusing. We present a 532 nm ultrashort-pulse laser setup to process the inner parts of 15 m long beam vacuum tubes of the Large Hadron Collider (LHC). Picosecond pulses at a repetition rate of 200 kHz are guided through an optical fiber toward an inchworm robot traveling inside the beam pipe. The system was installed, characterized, and tested for reliability. First surface treatments achieved the required scan precision. Cu2O-dominated nano-features were observed when processing at high average laser power (5 W) and slow scanning speed (5 mm s-1) in nitrogen flow, and the maximum SEY of copper was decreased from 2.1 to 0.7.