The Half-lives of $^{132}$La and $^{135}$La

TL;DR

This study precisely measured the half-lives of $^{132}$La and $^{135}$La isotopes, which are important for medical applications, improving accuracy over previous data through gamma spectroscopy and ionization chamber methods.

Contribution

The paper provides more accurate and precise half-life measurements of $^{132}$La and $^{135}$La, enhancing nuclear data for medical use.

Findings

Half-life of $^{135}$La is 18.930(6) hours.

Half-life of $^{132}$La is 4.59(4) hours.

Results improve precision and accuracy of previous data.

Abstract

The half-lives of $^{135}$La and $^{132}$La were determined via gamma spectroscopy and high-precision ionization chamber measurements. The results are 18.930(6) h for $^{135}$La and 4.59(4) h for $^{132}$La compared to the previously compiled values of 19.5(2) h and 4.8(2) h, respectively. The new results represent an improvement in the precision and accuracy of both values. These lanthanum isotopes comprise a medically interesting system with positron emitter $^{132}$La and Auger electron emitter $^{135}$La forming a matched pair for internal diagnostics and therapeutics. The precise half-lives are necessary for proper evaluation of their value in medicine and for a more representative tabulation of nuclear data.