Sub-nanosecond time resolution detector based on APD for Synchrotron Radiation ultrafast experiments

TL;DR

This paper presents a silicon avalanche photodiode (APD) based detector capable of sub-nanosecond time resolution for ultrafast synchrotron radiation experiments, enabling high counting rates and precise timing.

Contribution

The study designs and demonstrates a high-speed detector with a custom fast amplifier achieving below 1ns time resolution using APD technology.

Findings

Time resolution below 1ns FWHM achieved

High counting rate capability demonstrated

Effective circuit design for noise reduction

Abstract

Synchrotron radiation light sources produce intense beam of X-ray with ultra-short pulse and nanosecond period. This of-fers the opportunities for the time resolution experiments. Achieving higher counting rate and faster arriving time is diffi-cult for common detectors. But avalanche photodiodes (APD) based on silicon which have been commercially available1 with large active areas (e.g.10mmx10mm@ Perkin-Elmer Inc.) could satisfy the demands due to their good time resolution, low noise and large area.We investigate the high counting rate and nanosecond time resolution detector with APD. The detector's fast amplifier was designed with the gain of about 60dB (1000). The amplifier included with three stages RF-preamplifier using MAR6+ chip5 for the carefully controlling the circuit oscillation. Some measures have been taken for the preamplifiers good performance such as using resistance net between RF-preamplifier chip and the isolation of high voltage circuit from the preamplifier. The time resolution of the preamplifier together with APD sensor could reach below 1ns FWHM.