Performance study and calibration strategy of the HADES scintillator TOF Wall with fast digital readout

TL;DR

This paper details a calibration method and performance evaluation of scintillator bars in the HADES TOF detector, achieving improved timing accuracy through position-dependent calibration with digital electronics.

Contribution

It introduces novel calibration techniques for digital readout in scintillator-based TOF detectors, enhancing timing precision by accounting for position sensitivity.

Findings

Timing accuracy improved from 190 ps to 135 ps for shortest rods

Position dependence significantly affects calibration parameters

Results align with previous measurements of scintillator degradation length

Abstract

We present in this work the calibration procedure and a performance study of long scintillator bars used for the time-of-flight (TOF) measurement in the HADES experiment. The digital front-end electronics installed at the TOF detector required to develop novel calibration methods. The exceptional performance of the spectrometer for particle identification and pointing accuracy allows one to determine in great detail the response of scintillators to minimum ionizing particles. A substantial position sensitivity of the calibration parameters has been found, in particular for the signal time walk. After including the position dependence, the timing accuracy for minimum ionizing particles was improved from 190~ps to 135~ps for the shortest rods (1475 mm) and to 165~ps for the longest (2356 mm). These results are in accordance with the time degradation length of the scintillator bars, as determined from previous measurements.