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

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Accelerators, spectrometers, detectors and associated equipment, 2014-05, Vol.745, p.57-62
• Main Authors: Gao, W., Liu, H., Gan, B., Hu, Y.
• Format: Article
• Language: English
• Subjects: ASIC; Channels; Charge; Charge-sensitive amplifiers (CSA); Chips; CZT detectors; Detectors; Front-end; Imaging; Positron emission; Positron emission tomography (PET); Prototypes; Readout; Tomography
• ISSN: 0168-9002; 1872-9576
• DOI: 10.1016/j.nima.2014.01.059

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.