Preparation and characterisation of isotopically enriched Ta$_2$O$_5$ targets for nuclear astrophysics studies

TL;DR

This paper details the production and detailed characterization of isotopically enriched Ta$_2$O$_5$ targets, optimized for precise nuclear astrophysics experiments involving proton reactions, ensuring high purity and durability under experimental conditions.

Contribution

It introduces a novel method for preparing and characterizing isotopically enriched Ta$_2$O$_5$ targets suitable for astrophysical reaction studies, with minimized contamination.

Findings

Targets successfully prepared with high isotopic purity.

Characterization confirmed target stability and low contamination.

Suitable for proton capture measurements in astrophysics.

Abstract

The direct measurement of reaction cross sections at astrophysical energies often requires the use of solid targets of known thickness, isotopic composition, and stoichiometry that are able to withstand high beam currents for extended periods of time. Here, we report on the production and characterisation of isotopically enriched Ta$_2$O$_5$ targets for the study of proton-induced reactions at the Laboratory for Underground Nuclear Astrophysics facility of the Laboratori Nazionali del Gran Sasso. The targets were prepared by anodisation of tantalum backings in enriched water (up to 66% in $^{17}$O and up to 96% in $^{18}$O). Special care was devoted to minimising the presence of any contaminants that could induce unwanted background reactions with the beam in the energy region of astrophysical interest. Results from target characterisation measurements are reported, and the conclusions for proton capture measurements with these targets are drawn.