Characteristics of a multichannel low-noise front-end ASIC for CZT-based small animal PET imaging

Abstract

In this paper, we present the design and characteristics of a novel low-noise front-end readout application-specific integrated circuit dedicated to CdZnTe (CZT) detectors for a small animal PET imaging system. A low-noise readout method based on the charge integration and the delayed peak detection is proposed. An eight-channel front-end readout prototype chip is designed and implemented in a 0.35μm CMOS process. The die size is 2.3mm ×2.3mm. The prototype chip is tested in different methods including electronic test, energy spectrum test and irradiation test. The input range of the ASIC is from 2000e− to 180,000e−, reflecting the energy of the gamma ray from 11.2keV to 1MeV. The gain of the readout channel is 65mV/fC at the shaping time of 1μs. The best test result of the equivalent noise charge (ENC) is 58.9e− at zero farad plus 5.4e− per picofarad. The nonlinearity and the crosstalk are less than 3% and less than 2%, respectively, at the room temperature. The static power dissipation is about 3mW/channel.