Optimization of data acquisition parameters for single gamma line sensing: KSr_2I_5:Eu~(2+) and NaI(Tl) compared

摘要

KSr2I5:Eu2+ scintillators exhibit better than 3% energy resolution at 662 keV and may be significantly less expensive to produce than other, similar energy resolution scintillators. However, KSr2I5:Eu2+ exhibits a 6.5 Bq/cm(3) intrinsic background from the presence of 40 K. This background is not only the well-known 1.46 MeV gamma, but also the 1.31 MeV end point of the beta spectrum. This paper computationally evaluates the optimum data acquisition parameters of KSr2I5:Eu2+ and compares them to NaI(Tl) for the detection of single line gamma sources between 0.01-2.2 MeV with incident source strengths between 5 s(-1) and 100 s(-1) striking the detector. We found a strong dependence of the time-to-detection on the data acquisition parameters, where the time-to-detection of KSr2I5:Eu2+ was 1-3 times larger than NaI(Tl) across the parameter space. The largest discrepancy observed was between 0.6 MeV and 1.2 MeV, where the intrinsic 1.31 MeV beta dominates the background.