Study of auto-ionization probability following nuclear beta decay

Abstract

The purpose of the work was a study of autoionization phenomenon following nuclear beta--decay.

Three approaches have been adopted in this respect, first, a study of total internal ionization probability and internal ionization probability as a function of beta--particle energy, using a coincidence technique between emitted electrons (beta--particles + orbital electrons) and subsequent K X-rays. Two isotopes have been studied using this approach, thallium-204 and promethium-147, where measurements of internal ionization probabilities for K-electrons are presented and results are discussed in terms of available theoretical treatments on total internal ionization.

A second approach was applied in the case of thallium-204 where the internal ionization probability for K-electrons is deduced by comparison of mercury K X-rays resulting from an electron capture process with lead K X-rays due to the studied phenomenon.

The third approach was applied in a measurement on erbium-169 using the straight forward technique of comparing the 118 Kev gamma-ray transition with thulium K X-rays and cn upper limit for K-shell internal ionization probability has been estimated. Difficulties and drawbacks of the experiment have been discussed. The two solid state detectors used in this work were a lithium drifted silicon detector for electrons and lithium drifted germanium X-ray detector for photons.