ABSOLUTE Β-Counting IN a PROPORTIONAL FLOW-COUNTER

Abstract

Self-absorption and backscattering of β-particles have been studied in a proportional flow-counter, and empirical formulae are obtained to correct for these factors in absolute β-counting. The correction factors will depend on the thickness of the sample, the atomic number of the backscattering material, and the maximum energy of the β-particles. Relationships between the mass-absorption coefficient and the maximum energy of the β-particles for the primary β-particles, and between the mass-absorption coefficient, the maximum energy of the β-particles, and the atomic number of the backscattering material for the backscattered β-particles, are obtained. The backscattering function is found to depend on the atomic number of the backscattering material alone.

Direct Determination of 90Sr and 147Pm by Absolute β Counting in Aerosol Samples Collected after the Chernobyl Accident

“…(6). Self-scattering has been investigated by several authors [4,5,27,28]. Their results show that the value of the self-scattering factor,/ ss , in our case (large solid angle; thin sample made of a low atomic number material; strongly decreasing exponential activity distribution) is probably close to unity.…”