Multichannel FPGA based MVT system for high precision time (20~ps~RMS) and charge measurement

TL;DR

This paper presents a compact FPGA-based multi-channel system capable of high-precision time (20 ps RMS) and charge measurements for fast signals, suitable for advanced PET imaging applications.

Contribution

It introduces a novel FPGA-based multi-voltage threshold system with integrated TDCs, achieving high precision and low cost for multi-channel signal processing.

Findings

Achieved 20 ps RMS time measurement precision.

Demonstrated system time resolution of approximately 68 ps in PET applications.

Validated system performance with 192-channel TDC board in real-world tests.

Abstract

In this article it is presented an FPGA based $M$ulti-$V$oltage $T$hreshold (MVT) system which allows of sampling fast signals ($1-2$ ns rising and falling edge) in both voltage and time domain. It is possible to achieve a precision of time measurement of $20$ ps RMS and reconstruct charge of signals, using a simple approach, with deviation from real value smaller than 10$\%$. Utilization of the differential inputs of an FPGA chip as comparators together with an implementation of a TDC inside an FPGA allowed us to achieve a compact multi-channel system characterized by low power consumption and low production costs. This paper describes realization and functioning of the system comprising 192-channel TDC board and a four mezzanine cards which split incoming signals and discriminate them. The boards have been used to validate a newly developed Time-of-Flight Positron Emission Tomography system based on plastic scintillators. The achieved full system time resolution of $\sigma$(TOF) $\approx 68$ ps is by factor of two better with respect to the current TOF-PET systems.