Development of a Low-Noise Front-end ASIC for CdTe Detectors

Dec 18, 2019, 9:20 AM
Sun: B1F-Meeting rooms#4-6; Mon-Wed: B2F-RAN (International Conference Center Hiroshima)

Sun: B1F-Meeting rooms#4-6; Mon-Wed: B2F-RAN

International Conference Center Hiroshima

Peace Memorial Park, Hiroshima-shi
ORAL ASICs Session11


Mr Tenyo Kawamura (Kavli IPMU, University of Tokyo)


We have developed a series of front-end ASICs with spectroscopic capability for hard X-ray and gamma-ray imaging applications. Our latest ASIC, the “KW04H64” is designed for in-vivo molecular imaging, in which molecules are labeled with radioisotopes and injected into a small animal and their distribution in a body is detected externally. It requires a radiation detector that has good spatial and energy resolution and also covers a large detection area. The ASIC measures 7.12 mm x 8.03 mm and was implemented with X-fab 0.35 um CMOS technology. It consists of 64 readout channels and each channel contains a charge sensitive amplifier (CSA) including leakage current compensation function, a pole-zero cancellation circuit, two kinds of low pass filter (fast/slow shaper) capable of baseline adjustment for energy and timing measurement, a comparator, a sample and hold circuit, and a 10-bit Wilkinson ADC with common mode subtraction function. According to the photon energy range, the dynamic range can be changed by setting the register controlling the gain of the CSA. A novel function of the ASIC is that the voltage output of the fast shaper can be also digitized, which provides a user friendly method for adjusting the baseline of it. In the highest gain mode, the dynamic range is ~40,000 e- and the noise performance is 31 e- + 5.1 e-/pF from simulation. Besides the performance verification test of the ASIC itself, we also connected the ASIC to a CdTe detector and measured the spectrum of the radioactive sources of Am-241 and Ba-133. In this presentation, we will report on the results of the performance of the ASIC itself and the detector system, including the comparison with predictions made by simulations.

Submission declaration Original and unpublished

Primary author

Mr Tenyo Kawamura (Kavli IPMU, University of Tokyo)


Dr Tadashi Orita (Kavli IPMU, University of Tokyo) Dr Shin'ichiro Takeda (Kavli IPMU, University of Tokyo) Dr Shin Watanabe (JAXA/ISAS) Prof. Hirokazu Ikeda (JAXA/ISAS) Prof. Tadayuki Takahashi (Kavli IPMU, University of Tokyo)

Presentation materials