Surface and Underground Ultra Low-Level Liquid Scintillation Spectrometry
Gran Sasso National Laboratory
liquid scintillation methods
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CitationPlastino, W., & Kaihola, L. (2004). Surface and underground ultra low-level liquid scintillation spectrometry. Radiocarbon, 46(1), 97-104.
DescriptionFrom the 18th International Radiocarbon Conference held in Wellington, New Zealand, September 1-5, 2003.
AbstractCosmic background and its variation have been removed in the Gran Sasso National Laboratory (National Institute of Nuclear Physics) by its 1400-m rock overburden. Stable, high-performance liquid scintillation counting conditions are obtained when any remaining variable components of the environmental background, such as radon, are eliminated. The ultra low-level liquid scintillation spectrometer Quantulus(TM) has an anti-Compton guard detector (guard for short) that allows monitoring of gamma radiation in the background. The guard detector efficiency in radiocarbon background reduction is 8% in the Gran Sasso National Laboratory, while 80% is observed in surface laboratories. Thus, atmospheric pressure variations in surface laboratories cause variation in cosmic radiation flux. The Quantulus anti-Compton detector is highly efficient in detecting cosmic radiation, and the sample count rate remains stable in long-term counting. Also, correlation of sample backgrounds with environmental gamma radiation in various laboratories is examined.