Design and implementation of a front-end amplifier with over 100 dB dynamic range and 40 MHz bandwidth

Abstract

In the high-energy astrophysical research, high-power laser-plasma experiments, and many fields, the detection of particles with wide energy range or radiation fields with wide flux range is required. However, the dynamic range of most radiation detector systems are not exceeding four orders of magnitude due to the limiting dynamic range of readout electronic circuits, which cannot satisfy the requirement. This paper proposes a preamplifier circuit design for radiation detectors with high dynamic range and high bandwidth. The preamplifier is a transimpedance amplifier with two feedback loops, featuring a fast trigger and switch circuit to automatically adjust the amplifier’s gain. Ultimately, the circuit achieved a dynamic range of over five orders of magnitude at a 40 MHz bandwidth, reaching 102.59 dB. Used in a liquid scintillation detector readout system, the preamplifier was tested in an n-$\gamma$ discrimination experiment. The experimental results show that, coupling the detector with this circuit achieves a larger dynamic range detection and better n-$\gamma$ discrimination capability.