Quantification of Oxygen and Carbon in Calcium Targets for Reliable Ca$(p,p\alpha)$ Measurements

TL;DR

This study develops a data-driven method to accurately quantify oxygen and carbon impurities in calcium targets, enabling reliable Ca$(p,peta)$ measurements without relying on assumptions or models.

Contribution

It introduces a novel experimental approach using proton elastic scattering to determine impurity ratios directly from data, improving the accuracy of cross section measurements.

Findings

Accurate impurity ratios for calcium isotopes were obtained using 65-MeV proton elastic scattering.

The method allows for subtraction of O and C contributions in 392-MeV $(p,peta)$ spectra.

The approach enhances the reliability of Ca$(p,peta)$ cross section data.

Abstract

Reliable extraction of Ca$(p,p\alpha)$ cross sections requires accurate correction for oxygen and carbon impurities in calcium targets. In this work, the relative amounts of these light elements in $^{40,42,44,48}$Ca targets are determined using 65-MeV proton elastic scattering, where the Ca/Mylar yield ratios provide a direct measure of the corresponding O and C atomic ratios. These experimentally determined ratios are then applied to the 392-MeV $(p,p\alpha)$ spectra to subtract the O and C contributions in a fully data-driven manner. The method does not rely on assumptions about absolute contamination levels or reaction-model calculations, and enables a consistent and reliable determination of Ca$(p,p\alpha)$ yields across the calcium isotopic chain.