Speaker
Description
SOPHIAS detectors have been developed for x-ray free-electron laser (XFEL) experiments [1]. The SOPHIAS sensor has 1.9 Mpixels with a pixel size of 30 um square. Recently, their applications have been extended to synchrotron radiation (SR) experiments, where their small pixel size has enabled various studies such as magnetic domain observation in hard x-ray transmission geometry, soft matter characterization by ultra-small angle scattering and coherent scattering in transmission and reflection geometries. In this paper, we report our investigations of SOPHIAS characteristics and performance improvements for the SR experiments. We have investigated true CDS(Correlate Double Sampling), and pseudo CDS operation modes in order to maximize the duty ratio while keeping the noise low. We have found that continuous illumination makes the true CDS mode erroneous results, and have chosen the pseudo CDS mode. In contrast to the XFEL experiments where the required exposure time is at most several tens of nanoseconds, synchrotron radiation experiments demands longer exposure. In the SOPHIAS operation for SR experiments, the sensors runs at 20 frames per seconds with an exposure time of 34 ms/frame(Duty 70%). The white defects then become prominent and degrade the noise and dynamic range. We report our effort to minimize the white defects as well.
