# Precise measurement of alpha_K and alpha_T for the 109.3-keV M4 transition in 125Te: Test of internal-conversion theory

## TL;DR

This study precisely measures the internal conversion coefficients for a specific transition in 125Te, confirming theoretical models that include atomic vacancies and resolving previous anomalies.

## Contribution

The paper provides accurate experimental ICC measurements for 125Te's 109.3-keV transition, validating theoretical calculations that incorporate atomic vacancies.

## Key findings

- Measured alpha_K and alpha_T with high precision.
- Results agree with Dirac-Fock calculations including atomic vacancies.
- Supports the theory that atomic vacancies influence ICCs.

## Abstract

We have measured the K-shell and total internal conversion coefficients (ICCs), alpha_K and alpha_T, for the 109.3-keV M4 transition in 125Te to be 185.0(40) and 350.0(38), respectively. Previously this transition's ICCs were considered anomalous, with alpha values lying below calculated values. When compared with Dirac-Fock calculations, our new results show good agreement. The alpha_K result agrees well with the version of the theory that takes account of the K-shell atomic vacancy and disagrees with the one that does not. This is consistent with our conclusion drawn from a series of high multipolarity transitions.