Integrating hybrid area detectors for storage ring and free-electron laser applications

Abstract

Hybrid Pixel Array Detectors (HPADs) have a major impact on the science performed at x-ray synchrotron radiation sources. Broadly speaking, HPADs are either of the photon-counting or integrating variety. The success of photoncounting HPADs at storage rings is well described in the contribution by Brönnimann and Trüb. However, for experiments at x-ray free-electron laser (XFEL) sources, as well as for many fast time-resolved measurements at storage ring sources, photon counting is not an option because too many x-ray photons arrive too quickly for counting electronics to keep up with the local count rate. In these cases fast analog integrating systems are mandatory. By using innovative and adaptive front ends, one can achieve both a high dynamic range and a noise sufficiently low for reliable single photon detection. For frame rates above a few tens of kilohertz, temporary in-ASIC frame storage is mandatory. This can either be done in digital or in analog from, each having advantages and disadvantages. HPADs also need to be designed to cope with x-ray damage from extremely high radiation doses provided by current and next-generation x-ray sources. All these developments are summarized, along with some representative groundbreaking experiments performed with integrating HPADs.