Direct observation of the longitudinal phase space distribution of electron beam for investigation of micro-bunching instability

2014 Fiscal Year Final Research Report

• Project/Area Number: 24651096
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Quantum beam science
• Research Institution: Tohoku University
• Principal Investigator: HAMA Hiroyuki 東北大学, 電子光理学研究センター, 教授 (70198795)
• Co-Investigator(Kenkyū-buntansha): HARA Toru 独立行政法人理化学研究所, 先端ビームチーム, チームリーダー (00280727) ; TOGAWA Kazuaki 独立行政法人理化学研究所, 先端ビームチーム, 先任研究員 (00342816)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 低エネルギー電子ビーム / 縦方向位相空間 / チェレンコフ光

Outline of Final Research Achievements

Based on momentum dependence of Cherenkov opening angle, we have proposed a novel diagnostic system for direct observation of longitudinal phase space distribution of low energy electron beam. A specially designed "Turtle-back Mirror" confines the Cherenkov light onto a focal line, and the longitudinal phase space can be obtained by taking a temporal information together. We have examined the system resolution by numerical ray-trace simulation for whole optical system, and a momentum resolution of 1.15 keV/c and a temporal resolution of 0.74 ps were found out for the complete optics. Meanwhile a test piece of Turtle-Back Mirror was manufactured, and we investigated the performance of it. Although the overall shape of the non-linear surface satisfied the requirement, the surface roughness was really unsatisfactory for better resolutions. Further improvement of the mirror surface is required.

Free Research Field

ビーム物理学