New Development Design of Low Current Measurement with Noise Reduction for High-Resolution System

The treatment of inoperable cancers in the therapy terminal in Lanzhou-China, which is located at the Institute of Modern Physics (IMP), permits to work on the actual front-end readout. The availability of detailed noise spectral density characteristics for the OPA amplifier helps to develop the noise error analysis for high-resolution. This work focused on the noise model of the detector-preamplifier, which presents the low noise circuit schematic of the Transimpedance (TIA). Considering the parasitical influences, we develop a new approach to detect the weak signals based on resonant frequency, 1/√L₁ (C₁+C_GS). In addition, the system eliminates leakage current in the reset switch and reduces the charge injection occur from the switches in the Gated Integrator (GI) and the configuration switch is made especially with two transmission gates switches, in series, with a grounded MOS switch, attached to the node between the two transmission gates switches and the linearity almost good.