Speaker
Description
The DANSS experiment at the Kalinin NPP measures the reactor
antineutrino flux and spectrum in order to search for sterile neutrinos
and to address a range of fundamental and applied physics problems.
The readout of the detector's 1 m³ plastic scintillator array is
based on a hybrid system including photomultiplier tubes (PMTs)
and silicon photomultipliers (SiPMs).
High-precision Monte Carlo (MC) simulations, which
are essential for accurate energy reconstruction, require detailed
modeling of the PMT response. This work focuses on the
analysis of the single-photoelectron (SPE) signal characteristics in
these PMTs. To extract these characteristics, the photocathodes were
illuminated with low-intensity LED pulses of varying brightness. The
measured amplitude spectra were approximated using a convolution of a
Poisson distribution — accounting for electron emission statistics from
the photocathode and first dynode — and a Gaussian function representing
electronic noise. By analysis of the dependence of the fit parameters on
light intensity, we derived characteristics for each
individual PMT. The averaged key parameters of the readout system were
determined and successfully implemented into the DANSS MC simulation
framework.
