Development of a two-dimensional ASIC for hard X-ray spectroscopy and imaging with a CdTe pixel detector

We are developing a two-dimensional analog ASIC for the readout of pixel sensors based on silicon (Si) or cadmium telluride (CdTe) for spectroscopic imaging observations in the X-ray and gamma-ray regions. The aim for the ASIC is to obtain a low-noise performance better than 100 electrons (rms) with self-triggering capabilities. As the first step of prototyping, we have fabricated several ASICs. We obtained an energy resolution of 5.4 keV (FWHM) for 81 keV gamma-rays from 133Ba with a one-dimensional ASIC connected to a CdTe diode and also verified a readout architecture via a two-dimensional ASIC with 144 pixel channels. Based on the results obtained and experience gained through prototype ASICs, we are developing a 4096-channel two-dimensional analog ASIC.