Tests of PMT Signal Read-out of Liquid Argon Scintillation with a New Fast Waveform Digitizer

TL;DR

This paper evaluates the CAEN V1751 waveform digitizer for liquid argon scintillation detection, demonstrating its suitability for fast signal reconstruction and energy range detection in dark matter experiments.

Contribution

It introduces and tests the CAEN V1751 digitizer in real conditions, showing its effectiveness for liquid argon scintillation signal read-out.

Findings

Sampling at 1 or 2 GS/s accurately reconstructs fast scintillation components.

The digitizer's extended dynamic range enables detection of relevant energy signals.

Bandwidth and noise levels are adequate for dark matter detection applications.

Abstract

The CAEN V1751 is a new generation of Waveform Digitizer recently introduced by CAEN SpA. It features 8 Channels per board, 10 bit, 1 GS/s using Flash ADCs Waveform Digitizers (or 4 channels at 2 GS/s in Dual Edge Sampling mode) with threshold and Auto-Trigger capabilities. This provides a good basis for data acquisition in Dark Matter searches using PMTs to detect scintillation light in liquid argon, as it matches the requirements for measuring the fast scintillation component. The board was tested by operating it in real experimental conditions and by comparing it with a state of the art digital oscilloscope. We find that the sampling at 1 or 2 GS/s is appropriate for the reconstruction of the fast component of the scintillation light in argon (characteristic time of about 6-7 ns) and the extended dynamic range, after a small customization, allows for the detection of signals in the range of energy needed. The bandwidth is found to be adequate and the intrinsic noise is very low.