Noise Analysis of Current Sensitive Preamplifiers and Influence on Energy Resolution of NaI:Tl Detector System

Current Sensitive Preamplifiers (CSPs) are widely used in front-end electronics in data acquire system (DAQ), due to their ability to amplify signals directly. The optimization of energy resolution requires CSPs with suitable parameters such as gain, bandwidth, and low noise, etc. With the rapid improvement of CSP's bandwidth and trans-impedance gain, it is necessary to know how does the output noise of CSPs effect the energy resolution. For this purpose, we built the noise model of CSPs and analyzed the output noise voltage density of CSPs based on different commercial operation amplifiers (OP AMPs). Theoretical and experimental results shown that OP AMPs with low input noise voltage density is superior than others on energy resolution. Moreover, noise normalization factor has been defined to verify the relationship between energy resolution and noise of CSPs. The experimental results shown that the energy resolution and noise normalization factor are linearly conformable. This paper can provide reference on selecting commercial OP AMPs to design CSPs for optimization of energy resolution.