Performance of an improved readout IC for multi-energy photon-counting x-ray detector arrays

We present the design and initial performance characterization of the XENA-2 readout IC for solid-state x-ray detector arrays. XENA-2 consists of 32 readout channels, each with charge-sensitive input amplifier, adjustable two-stage gain amplifier and five comparators with 16-bit pulse counters. Readout of the counters, over a 16-bit data bus, takes approximately 20 μs. Compared to the XENA chip, its predecessor, this new IC's main improvement is significantly reduced noise, which allows for lower comparator thresholds and increased count rates.