# Non-linearity effects on the light-output calibration of light charged particles in CsI(Tl) scintillator crystals

## TL;DR

This study investigates how non-linear effects influence the calibration of light output in CsI(Tl) scintillators for light charged particles, proposing a new empirical model to improve accuracy across various energies.

## Contribution

The paper introduces a novel empirical parametrization of the hydrogen light output that accounts for non-linearities caused by Tl doping and light collection inefficiencies in CsI(Tl) crystals.

## Key findings

- Non-linearities significantly affect light output calibration.
- The new empirical model provides consistent results across multiple crystals.
- Calibration accuracy improves for hydrogen isotopes in CsI(Tl) detectors.

## Abstract

The light output produced by light ions (Z<=4) in CsI(Tl) crystals is studied over a wide range of detected energies (E<=300 MeV). Energy-light calibration data sets are obtained with the 10 cm crystals in the recently upgraded High-Resolution Array (HiRA10). We use proton recoil data from 40,48Ca + CH2 at 28 MeV/u, 56.6 MeV/u, 39 MeV/u and 139.8 MeV/u and data from a dedicated experiment with direct low-energy beams. We also use the punch through points of p, d, and t particles from 40,48Ca + 58,64Ni, 112,124Sn collisions reactions at 139.8 MeV/u. Non-linearities, arising in particular from Tl doping and light collection efficiency in the CsI crystals, are found to significantly affect the light output and therefore the calibration of the detector response for light charged particles, especially the hydrogen isotopes. A new empirical parametrization of the hydrogen light output, L(E,Z=1,A), is proposed to account for the observed effects. Results are found to be consistent for all 48 CsI(Tl) crystals in a cluster of 12 HiRA10 telescopes.