Determination of radioactive bulk and surface concentration by beta-detection

Abstract

A quantitative method for the analysis of [B-emitters in "infinitely" thin and thick samples was described in Part I. The calculation of errors in intensity, intensity ratio and activity concentration is discussed here in detail. Different definitions of detection sensitivity are compared and evaluated on the basis of the relative statistical error associated therewith. Dependence between the relative error of the net signal and the required measurement time is deduced and illustrated. A rapid analysis of [3-emitting isotopes requiring only identical sample preparation methods for calibration and unknown sources was described in Part I. 1 As the data processing procedure implies subs~tial approximations a detailed study on sources of error is mandatory. Error analyses of measurements and calculations of intensities, intensity ratios, calibration parameters and activity concentrations are presented on the basis of the widely accepted principles of CURRIE 2 and ROGERS. 3 Analysis of errors related to the inherent uncertainties of nuclear events and their measurement were based on the standard statistical treatise elaborated by e.g. BROWNLEE. 4 These principles and problems are also described in acknowledged university textbooks. 5 The applications of our presented principles and methods of calculation are illustrated in the numerical results shown in Paris 1 and III of this paper. 1,6