Charge sharing effects in pixellated photon counting detectors

A large area detector (LADI) has been designed for use in synchroton radiation sources. This single photon counting pixel detector has 150 um square pixels each capable of a rate up to 1 MHz. A 15 bit counter on each pixel yields a high dynamic range, required for X-ray diffraction measurements. The detectors have been tested at the SRS in Daresbury and with laboratory based X-ray sources. The results presented focus on the influence of different energy X-rays and the dependence on the threshold. Effects of charge sharing were studied using the proportion of double hits. The effective pixel size may be reduced by increasing the threshold, and introducing an insensitive area around each pixel, at the cost of also increasing the statistical errors.