FAST PHOTOCONDUCTOR CDTE DETECTORS FOR SYNCHROTRON X-RAY STUDIES

The Advanced Photon Source will be the brightest source of synchroton X-rays when it becomes operational in 1996. During normal operation, t he ring will be filled with 20 bunches of positrons with an interbunch spacing of 184 ns and a bunch width of 72 ps. To perform experiments with X-rays generated by positions on these time scales, one needs ext remely high speed detectors. To achieve the necessary high speed, we a re developing MBE-grown CdTe-based photoconductive position sensitive array detectors. The arrays fabricated have 64 pixels with a gap of 10 0 mum between the pixels. The high speed response of the devices was t ested using a short pulse laser. X-ray static measurements were perfor med using an X-ray tube and synchrotron radiation to study the device' s response to flux and wavelength changes. In this paper, we shall pre sent the response of the devices to some of these tests and also discu ss different physics aspects that need to be considered when designing high speed detectors.