Implementation of A Nanosecond Time-resolved APD Detector System for NRS Experiment in HEPS-TF

TL;DR

This paper presents a nanosecond time-resolved APD detector system designed for Nuclear Resonance Scattering experiments at HEPS-TF, achieving sub-nanosecond timing resolution with integrated sensors, amplifiers, and FPGA-based TDC readout.

Contribution

The paper introduces a novel detector system combining high-efficiency APD sensors, fast preamplifiers, and FPGA TDC for improved time resolution in NRS experiments.

Findings

Time resolution of 0.86 ns for the APD sensor and amplifier

Overall system time resolution of 1.4 ns

Effective detection of single photons in X-ray experiments

Abstract

A nanosecond time-resolved APD detector system is implemented for Nuclear Resonance Scattering (NRS) experiments in High Energy Photon Source-Test Facility (HEPS-TF) project of China. The detector system consists of three parts: the APD sensors, the fast preamplifiers and the TDC readout electronics. To improve the reception solid angle and the quantum efficiency, the C30703FH APDs (fabricated by Excelitas) are used as the sensors of the detectors. The C30703FH has an effective light-sensitive area of 10X10 mm2 and an absorption layer thickness of 110 {\mu}m. The fast preamplifier with gain of 59 dB and bandwidth of 2 GHz is designed to readout the weak signal outputted by the C30703FH APD. The detector system can work in single photon measurement mode because the preamplifier increases the signal-to-noise ratio. Moreover, the TDC is realized by FPGA multiphase method with a resolution bin of 1ns. The arrival time of all scattering events between two start triggers can be recorded by the FPGA TDC. In the X-ray energy of 14.4 keV, the time resolution (FWHM) of the developed detector (APD sensor + fast amplifier) is 0.86 ns, and the whole detector system (APD sensors + fast amplifiers + TDC readout electronics) achieves a time resolution of 1.4 ns.