Small scale prototype of a CdTe imaging system

We have designed a system for data acquisition from CdTe detectors. The system incorporates a USB2 interface motherboard, a shielded daughterboard which can be piggy-back connected to the previous one and Labview libraries. On the shielded board one can connect either a CdTe detector or a test capacitor. This board houses a mixed - signal ASIC containing various front-end readout architectures with and without discriminators and a wideband commercial amplifier, which amplifies further the output of one readout chain and brings it to the levels required by multichannel analyzers. The USB2 interface card contains a digital ASIC with 32 20-bit counters accepting signals from the discriminators, an FPGA which interfaces the 20-bit bus of the digital ASIC to the 16-bit bus of the USB controller, the USB controller which coordinates the high speed (480Mbps) data transfer to the PC and controls the programmable current and voltage sources implemented on this board and used for the bias of the mixed-signal ASIC and for setting the thresholds of the discriminators. The Labview libraries contain the VIs required for the control a) of the data transfer to and from the PC and b) of the programmable sources. The system serves our need to evaluate the performance of the combined CdTe detectors and readout ASIC towards the implementation of a large scale imaging instrument for luggage inspection.