The application of the absorption method to the determination of the upper limits of continuous  -ray spectra

Abstract

(1) An objective method of treating absorption data is devised for obtaining the most reliable value for the upper limit of continuous β-ray spectra. (2) The effect of geometrical conditions, of change of source-intensity, and of source-thickness on the absorption curve and on the apparent upper limit is discussed. (3) Feather's empirical equation connecting range and energy of β rays is corrected in accordance with more recent determinations. The corrected equation is R=0.536E - 0.165. (4) The method is applied to absorption curves obtained for the β rays emitted from Mg27, Si31 and As76. The values 0.885 ± 0.068 g./cm2., 0.571 ± 0.047 g./cm2. and 1.400 ± 0.024 g./cm2. are in good agreement with the values obtained by other methods.