The level-1 trigger for the SuperCDMS experiment at SNOLAB

TL;DR

This paper describes the design and performance of a FPGA-based level-1 trigger system for the SuperCDMS SNOLAB dark matter experiment, achieving high resolution and efficiency for low-energy signals.

Contribution

It introduces a novel FPGA-based trigger system with a time-domain optimal filter and flexible logic, tailored for low-energy dark matter detection.

Findings

Baseline resolution of 0.38σn achieved

99.9% trigger efficiency at 1.1σn

Reliable dead-time-free triggering and vetoing

Abstract

The SuperCDMS SNOLAB dark matter search experiment aims to be sensitive to energy depositions down to O(1 eV). This imposes requirements on the resolution, signal efficiency, and noise rejection of the trigger system. To accomplish this, the SuperCDMS level-1 trigger system is implemented in an FPGA on a custom PCB. A time-domain optimal filter algorithm realized as a finite impulse response filter provides a baseline resolution of 0.38 times the standard deviation of the noise, $\sigma_n$, and a 99.9% trigger efficiency for signal amplitudes of 1.1 $\sigma_n$ in typical noise conditions. Embedded in a modular architecture, flexible trigger logic enables reliable triggering and vetoing in a dead-time-free manner for a variety of purposes and run conditions. The trigger architecture and performance are detailed in this article.