The Correction for Self-Weakening in -Ray Measurements

Experimental details are given for the determination of self-weakening of β-rays in thick samples. The self-weakening correction factor in the case of twelve radio-elements is found over a considerable region to depend logarithmically on the massthickness of the sample. The self-weakening half-thicknesses η 1/2 is as a rule 2.2 times larger than the external weakening half-thickness 1/2 . The logarithmic dependence of the self-weakening correction factor on mass-thickness and the value of the ratio η 1/2 / 1/2 are derived in a simplified theoretical treatment.