A Fully Integrated CMOS Readout Circuit for Particle Detectors

Novel schemes for a charge sensitive amplifier （CSA） and a CR-（RC）, semi-Gaussian shaper in a fully integrated CMOS readout circuit for particle detectors are presented. The CSA is designed with poly-resistors as feedback components to reduce noise. Compared with conventional CSA, the input referred equivalent noise charge（ENC） is simulated to be reduced from 5036e to 2381e with a large detector capacitance of 150pF at the cost of 0.5V output swing loss. The CR-（RC）,semi-Gaussian shaper uses MOS transistors in the triode region in series with poly-resistors to compensate process variation without much linearity reduction.

Tetracycline sensitizes TiO_(2) for visible light photocatalytic degradation via ligand-to-metal charge transfer

Treatment of antibiotics contaminated water remains a global environmental challenge.In this study,tetracycline(TC)was found to effectively sensitize pure TiO_(2) for visible light photocatalytic degradation via a ligand-to-metal charge transfer mechanism.The sensitization was attributed to the formation of TC-TiO_(2) complex and the overlap of the molecular orbitals of TC and the conduction band of TiO_(2).The intermediate degradation products of TC,however,did not sensitize TiO_(2),which was the reason for the low mineralization rate.Nevertheless,our results showed that the intermediate degradation products of TC had significantly reduced bactericidal effects and less induction of antibiotic-resistance genes(ARGs).This study showcases an effective treatment of antibiotics-containing wastewater using the most common photocatalyst TiO_(2) with reduced risk in the spread of ARGs.

A low noise and wide dynamic range preamplifier for HPGe detectors

Purpose HPGe detectors can be used for both dark matter search and neutrinoless double beta decay experiments.However,signal amplitudes of these two experiments are quite different.This paper presents the development of a wide dynamic range CMOS preamplifier for HPGe detectors,which can also be used for low light level photon detection.Methods The structure of a dual-stage dual-gain amplifier was adopted to receive the signals with charges ranging from~0.01 fC to 500 fC.A novel“pre-reset”technique has been proposed to reduce the dead time ratio for large signals.A prototype chip was fabricated and tested.Results A minimum ENC of 43 electrons has been achieved for the high-gain channel at 77 K and the maximum charge of the input signal could be up to 500 fC for the low-gain channel,corresponding to a dynamic range above 90 dB.Conclusions The dual-gain structure of the preamplifier and the“pre-reset”method have been successfully verified,which can be used for HPGe detectors for dark matter and neutrino experiments in the future.

Ultra-low Power CMOS Front-End Readout ASIC for Portable Digital Radiation Detector

An ultra-low power complementary metal-oxide-semiconductor （CMOS） front-end readout ASIC was developed for a portable digital radiation detector. The ASIC having a charge sensitive amplifier and a semi-Gaussian pulse-shaper was produced using the CSMC 0.5 μm DPDM process. The ENC noise of 363 e at 0 pF with a noise slope of 23 e/pF complies with the stringent low noise requirements. The peaking time was 250 ns at a 100 mV/fC conversion gain （detector capacitance is 20 pF）. By operating this frontend readout ASIC in the weak inversion region, the ultra-low power dissipation is only 0.1 mW/channel （3.0 V） Simulations and test results suggest that this design gives lower power consumption than the front-end readout ASICs working in the strong inversion and is appropriate for the portable digital radiation detectors.

A 97 dB dynamic range CSA-based readout circuit with analog temperature compensation for MEMS capacitive sensors

Abstract： This paper presents a charge-sensitive-amplifier （CSA） based readout circuit for capacitive microelectro-mechanical-system （MEMS） sensors. A continuous-time （CT） readout structure using the chopper technique is adopted to cancel the low frequency noise and improve the resolution of the readout circuits. An operational trans-conductance amplifier （OTA） structure with an auxiliary common-mode-feedback-OTA is proposed in the fully differential CSA to suppress the chopper modulation induced disturbance at the OTA input terminal. An analog temperature compensation method is proposed, which adjusts the chopper signal amplitude with temperature variation to compensate the temperature drift of the CSA readout sensitivity. The chip is designed and implemented in a 0.35μm CMOS process and is 2.1 × 2.1 mm2 in area. The measurement shows that the readout circuit achieves 0.9 aF/√H capacitive resolution, 97 dB dynamic range in 100 Hz signal bandwidth, and 0.8 mV/fF sensitivity with a temperature drift of 35 ppm/℃ after optimized compensation.