TY - GEN
T1 - The application of full spectrum analysis to NaI(Tl) gamma spectrometry for the determination of burial dose rates
AU - Bu, Minqiang
AU - Murray, Andrew S.
AU - Kook, Myungho
AU - Buylaert, Jan Pieter
AU - Thomsen, Kristina J.
PY - 2021
Y1 - 2021
N2 - In this study, we explored the potential of a NaI(Tl) scintillator-based gamma spectrometer for the accurate determination of burial dose rates in natural geological samples using a full spectrum analysis (FSA) approach. In this method, an iterative reweighted least-square regression is used to fit calibration standard spectra (40K, and 238U and 232Th series in equilibrium) to the sample spectrum, after subtraction of an appropriate background. The resulting minimum detection limits for 40K, 238U, and 232Th are 4.8, 0.4 and 0.3 Bq·kg-1, respectively (for a 0.23 kg sample); this is one order of magnitude lower than those obtained with the three-window approach previously reported by us, and well below the concentrations found in most natural sediments. These improved values are also comparable to those from high-resolution HPGe gamma spectrometry. Almost all activity concentrations of 40K, 238U, and 232Th from 20 measured natural samples differ by ≤5% from the high resolution spectrometry values; the average ratio of dose rates derived from our NaI(Tl) spectrometer to those from HPGe spectrometry is 0.993 ± 0.004 (n=20). We conclude that our scintillation spectrometry system employing FSA is a useful alternative laboratory method for accurate and precise determination of burial dose rates at a significantly lower cost than high resolution gamma spectrometry.
AB - In this study, we explored the potential of a NaI(Tl) scintillator-based gamma spectrometer for the accurate determination of burial dose rates in natural geological samples using a full spectrum analysis (FSA) approach. In this method, an iterative reweighted least-square regression is used to fit calibration standard spectra (40K, and 238U and 232Th series in equilibrium) to the sample spectrum, after subtraction of an appropriate background. The resulting minimum detection limits for 40K, 238U, and 232Th are 4.8, 0.4 and 0.3 Bq·kg-1, respectively (for a 0.23 kg sample); this is one order of magnitude lower than those obtained with the three-window approach previously reported by us, and well below the concentrations found in most natural sediments. These improved values are also comparable to those from high-resolution HPGe gamma spectrometry. Almost all activity concentrations of 40K, 238U, and 232Th from 20 measured natural samples differ by ≤5% from the high resolution spectrometry values; the average ratio of dose rates derived from our NaI(Tl) spectrometer to those from HPGe spectrometry is 0.993 ± 0.004 (n=20). We conclude that our scintillation spectrometry system employing FSA is a useful alternative laboratory method for accurate and precise determination of burial dose rates at a significantly lower cost than high resolution gamma spectrometry.
KW - NaI(Tl) detector
KW - Scintillation gamma spectrometry
KW - Full spectrum analysis (FSA)
KW - Minimum detection limit (MDL)
KW - Burial dose rate measurement
KW - OSL dating
U2 - 10.2478/geochr-2020-0009
DO - 10.2478/geochr-2020-0009
M3 - Article in proceedings
T3 - Geochronometria
SP - 161
EP - 170
BT - Conference Proceedings of the 5th Asia Pacific Luminescence and Electron Spin Resonance Dating Conference
PB - Sciendo
T2 - 5th Asia Pacific Luminescence and Electron Spin Resonance Dating Conference
Y2 - 15 October 2018 through 17 October 2018
ER -