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Application of the new Monte Carlo code AlfaMC to the calibration of alpha-particle sources

Jurado Vargas M., Fernández Timón A., García Orellana C.

Nukleonika

2015

Vol. 60, No. 3, part 2

651--655

Measurements of α-particle sources require corrections to the counting rate due to scattering and self- -absorption in the source and the backing material. In this study, we describe a simple procedure to estimate these corrections using the new Monte Carlo code AlfaMC to consider the effects of scattering and self-absorption conjointly, and so to determine the activity of α emitters. The procedure proposed was applied to 235UO2 sources deposited on highly polished platinum backings. In general, the dependence of the efficiency with source thickness was in good agreement with a simple model considering a linear and a hyperbolic behavior for thin and thick sources, respectively, although significant deviations from this model were found for very thin sources. For these very thin sources, the Monte Carlo simulation revealed to be as a required method in the primary calibration of α-particle sources. The efficiency results obtained by simulation with AlfaMC were in agreement with available efficiency data.

Incrustation of alpha-particle emitters in the source backing: influence on activity measurements

Jurado-Vargas M., Fernández-Timón A.

Nukleonika

2012

Vol. 57, No. 4

569-573

Alpha particles emitted from radioactive sources are often measured using a 2pi counting geometry in order to determine the activity with a low deviation. The ratio C2pi/A (counting rate/activity) can, however, deviate from the theoretical value of 0.5 because of backscattering in the backing material, scattering and absorption of alpha particles in the source. The experimental counting rates are, therefore, corrected for these effects (backscattering for all sources, plus self-absorption for sources of non-negligible thickness) to determine the real source activity. However, the corrections needed for situations corresponding to alpha-particle sources in which the radionuclides are not deposited but incrusted in the backing material have not been considered. The aim of the present work was therefore to study the influence that incrustation in the backing can have on the total detection efficiency, and hence on the activity estimated for the source. To this end, we used the Monte Carlo computer code SRIM to model the behaviour of the alpha particles in the backing material.

Sequential extraction of uranium isotopes in sediments from an estuary historically affected by anthropogenic inputs of natural radionuclides

Aguadol J., Bolivar J., Garcia-Tenorio R.

Prace Naukowe GIG. Górnictwo i Środowisko / Główny Instytut Górnictwa

2004

nr 1

64-64