YAG:Ce SCREEN MONITOR USING A GATED CCD CAMERA

Due to its good spatial resolution, the YAG:Ce screen monitor is often used for small beam profile measurement in the Linac and beam transport line. We constructed a high-resolution YAG:Ce screen monitor at KEK-ATF2 for the observation of small size beam. We tested two types of screen, one is ceramic (sintered alumina powder) YAG:Ce and the other is single crystal YAG:Ce. Both screens have 50μm thickness. To escape from the Synchrotron radiation(SR) from the upstream and the Coherent Optical radiation(COTR), we applied delayed timing of the gate for the CCD camera. A microscope having a spatial resolution of 4.3μm is set outside of vacuum chamber to observe the scintillation light from the YAG:Ce screen. The results of the difference between the two screens, the camera performance with delayed gate and the optical performance of microscope will be presented in this paper.