PeakOTron

A tool to perform automated fits of Silicon Photo-Multiplier charge spectra to extract useful parameters from experiments. PeakOTron can be used for detailed analyses of single spectra, and also for the automatic characterisation of large samples of SiPMs.

The starting values of the fit parameters are extracted from the charge spectra. The entire data, including the intervals in-between the photoelectron peaks, are fitted to determine parameters such as the mean number of detected photons, gain, gain spread, prompt cross-talk, pedestal, electronics noise, dark-count rate as well as probability and time constant of after-pulses.

Getting Started

1. Install Python 3.12
2. From the main PeakOTron folder, run:

   pip install -r requirements.txt

3. To run the example, use:

   python user/example.py

You can customize the run using the following command-line arguments:

-V_bd_hmt FLOAT         V_bd_hmt value (default: 26.1)
-V_0_hmt FLOAT          V_0_hmt value (default: 1.4)
-tau FLOAT              SLOW COMPONENT OF SIPM PULSE (default: 146.0)
-t_0 FLOAT              PRE-INTEGRATION TIME (default: 100.0)
-t_gate FLOAT           GATE LENGTH (default: 100.0)
-bin_0 FLOAT            SELECT FIRST BIN OF SPECTRUM (default: -100.0)
-truncate_nsigma0_up FLOAT  SCAN SPECTRUM FROM Q < Q_0 - 4 sigma_0 (default: 2.0)
-truncate_nsigma0_do FLOAT  EVALUATE SPECTRUM CHI2 IN Q_0 - x*sigma_0 < Q < Q_0 + 2*sigma_0 (default: 2.0)
-prefit_only            FIT THE WHOLE SPECTRUM (flag, default: False)
-folder STR             Directory containing the data files (default: 'data/ketek')

Example usage with custom parameters:

python user/example.py -tau 150 -t_gate 110 -folder data/custom_folder

References

Jack Rolph, Erika Garutti, Robert Klanner, Tobias Quadfasel, Jörn Schwandt: PeakOTron: A Python module for fitting charge spectra of Silicon Photomultipliers. doi.org/10.1016/j.nima.2023.168544