Trigger for the SoLid Reactor Antineutrino Experiment
This work addresses the problem of improving signal-background ratios for precise neutrino oscillation measurements in particle physics experiments, though it is incremental as it applies existing algorithmic methods to a specific experimental setup.
The paper tackled the challenge of real-time background and noise rejection for the SoLid reactor antineutrino experiment, which faces high backgrounds due to its overground location near a reactor, by implementing a firmware trigger on FPGA using peak counting and time-over-threshold algorithms to efficiently distinguish neutrons from background signals.
SoLid, located at SCK-CEN in Mol, Belgium, is a reactor antineutrino experiment at a very short baseline of 5.5 -- 10m aiming at the search for sterile neutrinos and for high precision measurement of the neutrino energy spectrum of Uranium-235. It uses a novel approach using Lithium-6 sheets and PVT cubes as scintillators for tagging the Inverse Beta-Decay products (neutron and positron). Being located overground and close to the BR2 research reactor, the experiment faces a large amount of backgrounds. Efficient real-time background and noise rejection is essential in order to increase the signal-background ratio for precise oscillation measurement and decrease data production to a rate which can be handled by the online software. Therefore, a reliable distinction between the neutrons and background signals is crucial. This can be performed online with a dedicated firmware trigger. A peak counting algorithm and an algorithm measuring time over threshold have been identified as performing well both in terms of efficiency and fake rate, and have been implemented onto FPGA.