TY - GEN
T1 - Exploration of activity measurements and equilibrium checks for sediment dating using thick-window Germanium detectors
AU - Warner, Jacob A.
AU - Fitzsimmons, Kathryn E.
AU - Reynolds, Eva M.
AU - Gladkis, Laura G.
AU - Timmers, Heiko
PY - 2011
Y1 - 2011
N2 - Activity measurements on sediment samples for trapped-charge geological dating using gamma-ray spectroscopy are an important verification of the field-site dose rate determination. Furthermore gamma-ray spectroscopy can check if the natural decay series are in secular equilibrium which is a crucial assumption in such dating. Typically the activities of leading members of the Thorium and Uranium decay series are measured, which requires Germanium detectors with thin windows and good energy resolution in order to effectively detect the associated low energy gamma-rays. Such equipment is not always readily available. The potential of conventional Germanium detectors with thick entrance window has been explored towards routine gamma-ray spectroscopy of sediment samples using higher energy gamma-rays. Alternative isotopes, such as Ac-228 and Pb-212 for the Thorium series, and Pa-234m, Ra-226 and Bi-214 for the Uranium series, have been measured in order to determine the mass-specific activity for the respective series and possibly provide a check of secular equilibrium. In addition to measurements of the K-40 activity, with the alternative approach, the activities of both decay series can be accurately determined. The secular equilibrium condition may be tested for the Thorium series. Measurement accuracy for Pa-234m is, however, not sufficient to permit also a reliable check of equilibrium for the Uranium series.
AB - Activity measurements on sediment samples for trapped-charge geological dating using gamma-ray spectroscopy are an important verification of the field-site dose rate determination. Furthermore gamma-ray spectroscopy can check if the natural decay series are in secular equilibrium which is a crucial assumption in such dating. Typically the activities of leading members of the Thorium and Uranium decay series are measured, which requires Germanium detectors with thin windows and good energy resolution in order to effectively detect the associated low energy gamma-rays. Such equipment is not always readily available. The potential of conventional Germanium detectors with thick entrance window has been explored towards routine gamma-ray spectroscopy of sediment samples using higher energy gamma-rays. Alternative isotopes, such as Ac-228 and Pb-212 for the Thorium series, and Pa-234m, Ra-226 and Bi-214 for the Uranium series, have been measured in order to determine the mass-specific activity for the respective series and possibly provide a check of secular equilibrium. In addition to measurements of the K-40 activity, with the alternative approach, the activities of both decay series can be accurately determined. The secular equilibrium condition may be tested for the Thorium series. Measurement accuracy for Pa-234m is, however, not sufficient to permit also a reliable check of equilibrium for the Uranium series.
KW - Gamma-ray detection
KW - Luminescence dating
KW - Natural decay series
KW - Trapped-charge dating
UR - http://www.scopus.com/inward/record.url?scp=79960120981&partnerID=8YFLogxK
U2 - 10.1063/1.3586091
DO - 10.1063/1.3586091
M3 - Conference contribution
SN - 9780735408913
T3 - AIP Conference Proceedings
SP - 213
EP - 218
BT - Application of Accelerators in Research and Industry - Twenty-First International Conference, CAARI 2010
T2 - 21st International Conference on Application of Accelerators in Research and Industry, CAARI 2010
Y2 - 8 August 2010 through 13 August 2010
ER -