Performance characterization of a silicon strip detector for spectral computed tomography utilizing a laser testing system

A new silicon strip detector with sub-millimeter pixel size operated in single photon-counting mode has been developed for use in spectral computed tomography (CT). An ultra fast application specific integrated circuit (ASIC) specially designed for fast photon-counting application is used to process the pulses and sort them into eight energy bins. This report characterizes the ASIC and detector in terms of thermal noise (0.77 keV RMS), energy resolution when electron-hole pairs are generated in the detector diode (1.5 keV RMS) and Poissonian count rate with retained count rate linearity and energy resolution (200 Mcps•mm^-2). The performance of the photon-counting detector has been tested using a picosecond pulsed laser system to inject energy into the detector, simulating x-ray interactions. The laser testing results indicate a good energy-discriminating capability of the detector, assigning the pulses to higher and higher energy bins as the intensity of the laser pulses are increased.