# Precise measurement of alpha_K for the 88.2-keV M4 transition in 127Te: Test of internal-conversion theory

## TL;DR

This study precisely measured the K-shell internal conversion coefficient for an 88.2-keV transition in 127Te, confirming the importance of atomic vacancy effects in theoretical calculations.

## Contribution

The paper provides the first precise experimental measurement of alpha_K for this transition, testing and validating specific internal-conversion theories.

## Key findings

- Measured alpha_K = 484(6)
- Results agree with vacancy-including theory
- Beta branching determined as 2.14(3)%

## Abstract

We have measured the K-shell internal conversion coefficient, alpha_K, for the 88.2-keV M4 transition from the 106-day isomer to the ground state in 127Te to be 484(6). When compared with Dirac-Fock calculations of alpha_K, this result agrees well with the version of the theory that incorporates the effect of the K-shell atomic vacancy and disagrees with the one that does not. As a byproduct of this measurement, we have determined the beta branching from the isomer to be 2.14(3)%.