# Measurement of $^{139}$La(p,x) Cross Sections from 35-60 MeV by Stacked-Target Activation

## TL;DR

This study measured the cross sections of $^{139}$La(p,x) reactions between 35-60 MeV using stacked-foil activation, providing data crucial for medical isotope production and revealing discrepancies with nuclear model predictions.

## Contribution

First experimental measurement of $^{139}$La(p,x) cross sections in the 35-60 MeV range using stacked-foil activation, aiding medical isotope development.

## Key findings

- Measured cross sections for nine radionuclides from 35-60 MeV.
- Significant deviations observed between experimental data and nuclear model predictions.
- Data supports improved modeling for medical isotope production.

## Abstract

A stacked-target of natural lanthanum foils (99.9119% $^{139}$La) was irradiated using a 60 MeV proton beam at the LBNL 88-Inch Cyclotron. $^{139}$La(p,x) cross sections are reported between 35-60 MeV for nine radionuclides. The primary motivation for this measurement was the need to quantify the production of $^{134}$Ce. As a positron-emitting analogue of the promising medical radionuclide $^{225}$Ac, $^{134}$Ce is desirable for in vivo applications of bio-distribution assays for this emerging radio-pharmaceutical. The results of this measurement were compared to the nuclear model codes TALYS, EMPIRE and ALICE (using default parameters), which showed significant deviation from the measured values.