Front-end ASIC for Co-Planar grid sensors

An Application Specific Integrated Circuit for Cadmium Zinc Telluride Co-Planar Grid sensors is presented. The ASIC provides low-noise amplification of grids and cathode signals, difference between grid signals with adjustable relative gain, shaped signals with baseline stabilization, and timing signals. In the current version the peaking time of the shaped pulses is 5 μs and the gain can be switched between 36 mV/fC and 18 mV/fC covering an energy range up to 3 MeV. Designed in CMOS 0.25μm technology it dissipates 25 mW from a single +2.5 V supply. A description of the ASIC and the results of its characterization with CdZnTe CPG sensors are presented. The system is analyzed in terms of resolution, and the impact of the noise correlation due to the inter-grid capacitance is discussed.