Development of a fast and high-resolution beam profile monitor with a laser wire target

点击翻译按钮获取中文摘要

Production of ultra low emittance electron beams is one of the essential techniques in realizing third-generation synchrotron radiation light sources, free electron lasers and/or high-energy electron linear colliders. The main purpose of the present research is to develop a precision beam profile monitor which can directory measure small electron beam sizes in a storage ring. This monitor is based on the Compton scattering of electrons with a laser wire, which is a thin light target installed in the beam. It is realized by injecting laser light into a Fabry-Perot optical cavity. We summarize the main results of this research below.(1) We developed an optical cavity with the power gain as large as 2000 and the laser beam waist of 11 um.(2) We successfully measured the electron beam sizes of the ATF damping ring operated in a single bunch mode, and demonstrated that it achieved the target emittance of 1.1x10^{-11} mrad in the vertical direction and 1.1x10^{-9} mrad in the horizontal.(3) We also measured the electron beam size in a multi-bunch mode, and found that there was no big bunch-to-bunch dependence. The present research established the techniques of the laser wire beam profile monitor and contributed to the understandings of ultra-low emittance beam dynamics.