Merlin: a fast versatile readout system for Medipix3

This contribution reports on the development of a new high rate readout system for the Medipix3 hybrid pixel ASIC developed by the Detector Group at Diamond Light Source. It details the current functionality of the system and initial results from tests on Diamond's B16 beamline. The Merlin system is based on a National Instruments PXI/FlexRIO system running a Xilinx Virtex5 FPGA. It is capable of recording Medipix3 256 by 256 by 12 bit data frames at over 1 kHz in bursts of 1200 frames and running at over 100 Hz continuously to disk or over a TCP/IP link. It is compatible with the standard Medipix3 single chipboards developed at CERN and is capable of driving them over cable lengths of up to 10m depending on the data rate required. In addition to a standalone graphical interface, a system of remote TCP/IP control and data transfer has been developed to allow easy integration with third party control systems and scripting languages. Two Merlin systems are being deployed on the B16 and I16 beamlines at Diamond and the system has been integrated with the EPICS/GDA control systems used. Results from trigger synchronisation, fast burst and high rate tests made on B16 in March are reported and demonstrate an encouraging reliability and timing accuracy. In addition to normal high resolution imaging applications of Medipix3, the results indicate the system could profitably be used in 'pump and probe' style experiments, where a very accurate, high frame rate is especially beneficial. In addition to these two systems, Merlin is being used by the Detector Group to test the Excalibur 16 chip hybrid modules, and by the LHCb VELO Pixel Upgrade group in their forthcoming testbeams. Additionally the contribution looks forward to further developments and improvements in the system, including full rate quad chip readout capability, multi-FPGA support, long distance optical communication and further functionality enhancements built on the capabilities of the Medipix3 chips.