Abstract-Monitoring of electron bunch length by using Terahertz coherent transition radiation

• Xiaolu Su, 
• Lixin Yan, 
• Yingchao Du, 
• Zhen Zhang, 
• Zheng Zhou, 
• Dong Wang, 
• Lianmin Zheng, 
• Qili Tian, 
• Wenhui Huang, 
• Chuanxiang Tang

• Department of Engineering Physics, Tsinghua University, Beijing, China
• Key Laboratory of Particle and Radiation Imaging (Tsinghua University), Ministry of Education, Beijing, China
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http://www.sciencedirect.com/science/article/pii/S0168583X17302550

In this paper, ultrashort bunch length monitoring was demonstrated based on Terahertz (THz) coherent transition radiation (CTR) in Tsinghua Thomson scattering X-ray (TTX) source. The radiation produced by electron bunch is split into three paths: one of them is used to detect the total energy, while the other two paths are filtered with different THz band-pass filters before detection. The bunch length variation can be obtained by calculating the ratio between the filtered energy and the total energy. The bunch is compressed by a chicane and via changing the current of chicane, the ratio of filtered energy and total energy changed correspondingly. It is a simple supplemental approach to monitor the bunch length during beam conditioning and facility operation. Bunch arrival-time jitter and nonlinear effects in chicane are observed in the experiment during the measurement of filtered energy and total energy.