Title :
Pulse height distributions of β rays in 14C measurement with liquid scintillation counting system Quantulus
Author :
Suzuki, A. ; Sakurai, H. ; Endo, K. ; Noma, M. ; Gunji, S. ; Inui, E. ; Hamano, M.
Author_Institution :
Dept. of Phys., Yamagata Univ., Japan
fDate :
6/1/1999 12:00:00 AM
Abstract :
To investigate the variations of the solar activity over a long time scale, we have started the measurements of 14C in an ancient tree, synthesizing 10 g benzene from the tree rings and using the liquid scintillation counting system Quantulus with ultra low background level. The background rate of the Quantulus was 1.2 cpm while the counting rate of 14C was 91.0 cpm for the ancient tree. The pulse height distribution of β rays from 14C was well fitted with theoretical β rays spectrum. The Quantulus detected β rays down to 7.5 keV with good detection efficiency. It was confirmed that the total counts from the 14C in the sample benzene can be measured within 0.2% accuracy on the basis of the pulse height distribution of a standard benzene sample, using the least squares fitting method
Keywords :
beta-ray detection; carbon; least squares approximations; liquid scintillation detectors; pulse height analysers; radioactive dating; radioisotopes; 14C measurement; C; Quantulus; ancient tree; benzene; beta measurement; detection efficiency; least squares fitting method; liquid scintillation counting system; pulse height distributions; solar activity; tree rings; Atmosphere; Atmospheric measurements; Cosmic rays; Energy measurement; Least squares methods; Magnetic field measurement; Pollution measurement; Pulse measurements; Radioactive materials; Time measurement;
Journal_Title :
Nuclear Science, IEEE Transactions on
