Evaluation of data-acquisition front ends for handling high-bandwidth data from X-ray 2D detectors: A feasibility study

Two-dimensional (2D) X-ray detectors are indispensable for synchrotron radiation and X-ray free-electron laser experiments, such as coherent X-ray imaging, spectroscopy, and time-resolved experiments. In these experiments, special, temporal, or photon-energy information is projected onto the surface of a 2D X-ray detector, and it is generally accepted that detectors with a larger number of pixels and a higher dynamic range will provide better information on the sample. An example of a high-performance application in this area is SOPHIAS (Silicon-On-Insulator Photon Imaging Array Sensor), which is a next generation detector under development at the SPring-8 facility, Japan. Since such systems demand a high-bandwidth front end for data acquisition (DAQ), a prototype front end for SOPHIAS is also under development. Here, we have performed a feasibility study of the prototype front end using an evaluation board, which consists of an FPGA (field-programmable gate array) with an FMC (FPGA mezzanine card) interface to support various physical layers of sensor readout modules and back-end DAQ. The bandwidths were measured for various combinations of protocols and physical layers. In many photon science applications, scalability from a single module to many modules is important, so a compact desktop-type DAQ system was also evaluated. Measurements of the bandwidth using the evaluation board indicated that an effective bandwidth of 9 Gbps and 16 Gbps was achieved using SFP+ (Small Form-factor Pluggable Plus) with XAUI (X (ten) Attached Unit Interface) and PCI Express (Peripheral Component Interconnect Express), respectively.