FPGA-based TDC for SiPM Timing and Amplitude Measurements

Lucas Finazzi; Felipe Soriano; Leandro Gagliardi; Federico Golmar

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arXiv · 2608.31135

FPGA-based TDC for SiPM Timing and Amplitude Measurements

Lucas Finazzi·Felipe Soriano·Leandro Gagliardi·Federico Golmar

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Abstract

Silicon photomultipliers (SiPMs) are widely used in photon-counting applications, such as positron emission tomography or particle physics, where precise timestamps and photoelectron number information are both required. In this work, a Time-to-Digital Converter with amplitude measurement capabilities was designed using an Artix-7 XC7A35T FPGA. For amplitude measurements, the internal xADC of the FPGA was chosen over other alternatives for simplicity. This design has two channels and can operate in timestamp-only mode or timestamp + amplitude mode. In turn, channels can be operated independently or in coincidence. The Integral Non-Linearity and Differential Non-Linearity of the design were studied, along with its time resolution, which is $(19 \pm 1)$ ps. Using a CAEN DT5810 pulse emulator, the design was tested further in timing-only mode, timing + amplitude mode and in coincidence mode to showcase its performance when using Poisson distributed SiPM-like pulses of various amplitudes.

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Lucas Finazzi, Felipe Soriano, Leandro Gagliardi, Federico Golmar. 2026-08-31. FPGA-based TDC for SiPM Timing and Amplitude Measurements. https://arxiv.org/abs/2608.31135

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