High-flux SiPM amplitude nonlinearity

Determine the amplitude nonlinearity of the μ36 detector’s silicon photomultiplier signal as a function of the number of incident photons under high-photon-flux conditions.

Background

The μ36 detector was designed to record individual cosmic muons, for which the photon yield reaching the silicon photomultiplier is relatively low. The paper applies a time-over-threshold correction based on simulated energy deposition and optical and electronic response parameters, but notes that this correction does not account for signal nonlinearity at high photon fluxes. Characterizing this nonlinearity is therefore necessary for accurately interpreting measurements involving the intense, multi-particle beams generated by laser-wakefield-accelerated electrons.