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Cosmic Background Reduction in the Radiocarbon Measurements by Liquid Scintillation Spectrometry at the Underground Laboratory of Gran Sasso

Published online by Cambridge University Press:  18 July 2016

Wolfango Plastino ,
Lauri Kaihola ,
Paolo Bartolomei  and
Francesco Bella
Wolfango Plastino
Affiliation:
Department of Physics, University of Roma Tre, via della Vasca Navale, 84, I-00146 Roma, Italy, and I.N.F.N., Section of Rome III, via della Vasca Navale, 84, I-00146 Roma, Italy. Email: [email protected].
Lauri Kaihola
Affiliation:
PerkinElmer Life Sciences, Wallac Oy, P.O.B. 10, FIN-20101 Turku, Finland
Paolo Bartolomei
Affiliation:
E.N.E.A., Radiocarbon Laboratory, via dei Colli, 16, I-40136 Bologna, Italy
Francesco Bella
Affiliation:
Department of Physics, University of Roma Tre, via della Vasca Navale, 84, I-00146 Roma, Italy
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Abstract

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Radiocarbon measurements by two 1220 Quantulus™ ultra low background liquid scintillation spectrometers were performed at the underground laboratory of Gran Sasso and the Radiocarbon Laboratory of E.N.E.A.-Bologna to study the efficiency and background variations related to measurement sites. The same configuration setup, i.e. the same center of gravity of the 14C spectrum (SQP(I) = 410 ± 1) was obtained in both instruments. Many different background and modern standards with pure analytical benzene were used and spectra for 40 one-hour periods were obtained. The data indicates a background reduction of approximately 65% between the surface and underground laboratories, with no differences in the efficiency. Recording similar efficiencies in both spectrometers is probably due to fairly identical photomultiplier characteristics. The cosmic noise reduction observed at the laboratory of Gran Sasso makes it possible to perform high precision 14C measurements and to extend for these idealized samples the present maximum dating limit from 58,000 BP to 62,000 BP (5 mL, 3 days counting).

Type
I. Becoming Better
Information
Radiocarbon , Volume 43 , Issue 2A: Proceedings of the 17th International Radiocarbon Conference (Part 1 of 3) , 2001 , pp. 157 - 161
Copyright
Copyright © The Arizona Board of Regents on behalf of the University of Arizona 

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