title: Compensation by the CIEMAT/NIST-method of long-term effects in LSC measurements of beta emitters.
abstract: A systematic evaluation of activity concentrations of 3H, 63Ni and 14C by using the CIEMAT/NIST method has been carried out over time intervals of 4, 2.4 and 2.3 years, respectively. It proves that the CIEMAT/NIST method can compensate, with no need for additional checking sources or procedures, for count losses and quench parameter reduction in long-term measurements with LSC spectrometers and allows one to obtain very accurate activity concentration values by using a quench curve close to the nuclide measurements. If this requirement of the method is not fulfilled, significant discrepancies, up to 5.6% for 3H, 1.5% for 63Ni and 0.35% for 14C, can be obtained in only 1-year time difference.
authors.affiliation: Laboratorio de Metrología de Radiaciones Ionizantes, National Standards Laboratory for Ionizing Radiations, CIEMAT, Madrid 28040. Spain.
authors.forename: L
authors.initials: L
authors.lastname: Rodríguez Barquero
authors.forename: J M
authors.initials: JM
authors.lastname: Los Arcos