Characterization protocol for a surface barrier-type alpha and beta detector

The purpose of this work is to present a protocol for characterization of an alpha (α), beta (β)(and also α + β) radiation detector of the surface-barrier type, currently in operation at the Institute of Chemical, Biological and Nuclear Defense of the Brazilian Technology Center (CTEx), located in Rio de Janeiro, Brazil. The detector has been efficiently used to measure the amount of contamination in samples collected from sites where accidental or deliberate releases of radioactive have occurred. Standard ²⁴¹Am and ⁹⁰Sr sources have been used for calibration and have consistently yielded the following values of efficiency for alpha and beta counting: 38% and 29%, respectively. Self absorption effects have also been investigated, providing data that were compared to those reported by a reference laboratory (LAPOC) in Poços de Caldas, Minas Gerais, Brazil. (paper)