Improvement of the energy resolution and non-proportional light response of CsI:Tl to gamma radiation using dynamic integration times

Abstract The analysis of the light response of thallium-doped cesium iodide to gamma radiation was performed on single scintillation waveforms recorded using a digital oscilloscope. As an alternative to classical pulse processing procedures, the use of dynamic integration times instead of fixed shaping/integration times was demonstrated. The dynamic integration time, changeable with the amplitudes of the CsI:Tl scintillation pulses, allowed to optimise the light collection with simultaneous minimization of a noise contribution. It was shown that for low-energy γ -rays (22 keV–60 keV), the scintillation pulses should be integrated using shorter integration times (approximately 7 μ s–14 μs), whereas for higher energies (662 keV–835 keV), the best energy resolution was achieved with integration times of about 28 μ s–30 μ s. The approach also allowed for the registration of more proportional CsI:Tl light responses to deposited X and gamma radiation in the energy range of 22 keV–835 keV.