title: A least squares procedure for calculating the calibration constants of a portable gamma-ray spectrometer.
abstract: In this study, a least squares procedure for calculating the calibration constants of a portable gamma-ray spectrometer using the general inverse matrix method is presented. The procedure weights the model equations fitting to the calibration data, taking into account the variances in the counting rates and in the radioactive standard concentrations. The application of the described procedure is illustrated by calibrating twice the same gamma-ray spectrometer, with two independent data sets collected approximately 18 months apart in the same calibration facility.
authors.affiliation: Departamento de Geofísica, Instituto de Astronomia, Geofísica e Ciências Atmosféricas da Universidade de São Paulo, Rua do Matão, 1226 Butantã, 05508-090 São Paulo, SP, Brasil. brenha@iag.usp.br
authors.forename: F B
authors.initials: FB
authors.lastname: Ribeiro
authors.forename: D U
authors.initials: DU
authors.lastname: Carlos
authors.forename: F Y
authors.initials: FY
authors.lastname: Hiodo
authors.forename: E F
authors.initials: EF
authors.lastname: Strobino
mesh_terms: D000465:Algorithms; D001938:Brazil; D002138:Calibration / Q000592:standards*; D019544:Equipment Failure Analysis / Q000379:methods* / Q000592:standards*; D016018:Least-Squares Analysis; D011834:Radiation Monitoring / Q000295:instrumentation* / Q000592:standards*; D013051:Spectrometry, Gamma / Q000295:instrumentation* / Q000592:standards*