Modeling and SPICE Simulation of the CdS/CdTe Neutron Detectors Integrated With Si-Poly TFTs Amplifiers

In this work, it is presented a unified model to integrate a radiation detector on a single chip using TFTs-based amplifiers, to fabricate a low-cost thermal neutron detector system. The model is based on the current-voltage experimental measurements of the CdS/CdTe detector and CMOS Si-Poly TFTs technology. Parameters obtained by $I-V$ and $C$ - $V$ analysis were introduced into Smart SPICE to design the amplifiers. The output voltage was simulated for a neutron capture event. Three amplification topologies were studied, obtaining an output voltage in the range of 180 to 260 mV with a generated photocurrent pulse around 3.5 $\mu \text{A}$ , which is high enough to be interfaced with a microcontroller. The neutron detector is integrated into TFT amplifiers with a gain of around 50 dB and bandwidth of 4.7 MHz at −3 dB.