The University of Arizona
Open Access Open Access  Restricted Access Subscription or Fee Access

Surface and underground ultra low-level liquid scintillation spectrometry.

Wolfango Plastino, Lauri Kaihola


Cosmic 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 (super 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.


absolute age;C 14;carbon ;Compton radiation;cosmic rays;Europe ;gamma rays;Gran Sasso National Laboratory;instruments ;isotopes ;Italy ;liquid scintillation methods;methods ;monitoring ;Quantulus ;radioactive isotopes;Southern Europe;underground installations

Full Text: