Speakers
Description
Lutetium–yttrium oxyorthosilicate (LYSO) crystals are widely recognized as fast scintillators, valued for their high light output and robust mechanical properties, which make them well suited for high-energy physics and space applications despite their intrinsic radioactivity. Although the non-proportional light response of LYSO scintillators has been extensively studied, discrepancies remain among published measurements of the light-yield quenching at high ionization densities with different charged particles. We report a measurement of the light response of a LYSO scintillator to stopping 𝛼 particles emitted by a 241 Am source performed in the laboratories of the University of Trento. A quenching factor, L/E = 0.075 ± 0.006, for 3.7 MeV 𝛼 particles has been inferred, in agreement with previous results obtained with He ions.
The time distribution of the scintillation decay has also been investigated, confirming the presence of two exponential components in the decay tail: 𝜏$_{fast}$ = 23.3 ± 0.7(stat.) ± 0.8(syst.) ns and 𝜏$_{slow}$ = 43.9 ± 0.5(stat.) ± 2.3(syst.) ns. The current measurement revealed that 𝛼 scintillation pulses are faster than 𝛽∕𝛾 ones. This behavior is quantitatively parameterized by a difference in the amplitude of the two scintillation components: $𝐴^𝛼_{slow}$ = (48.7 ± 3.3(stat.) ±15(syst.) )%, which is significantly smaller than $𝐴^{𝛽∕𝛾}_{slow}$ = (72.9 ± 1.3(stat.) ±3.5(syst.) )%. Finally, a minimal linear model, $𝐴_{slow}$ = $𝐴_0$ + $𝐴_1$ ($\frac{𝐿}{𝐸}$ ), with $𝐴_0$ = (42 ± 4(stat.) ± 4(syst.) )% and $𝐴_1$ = (35 ± 5(stat.) ± 4(syst.) )%, has been considered to test the hypothesis that the differences in LYSO light decay times measured with 𝛼 and 𝛽∕𝛾 events are related to scintillation quenching effects.