Gadolinium concentration measurement with an atomic absorption spectrophotometer

TL;DR

This paper explores three methods using atomic absorption spectrophotometry to accurately measure gadolinium sulfate concentrations in water, which is vital for neutron detection applications in Cherenkov detectors.

Contribution

It introduces three novel approaches with doping and platform techniques for precise Gd concentration measurement using AAS.

Findings

Doping with potassium and lanthanum improves measurement accuracy.

Using tantalum and tungsten platforms enhances detection reliability.

The methods enable impurity-free Gd concentration assessment.

Abstract

Because gadolinium (Gd) has the highest thermal neutron capture cross section, resulting in an 8 MeV gamma cascade upon capture, it has been proposed for dissolution in water Cherenkov detectors to achieve efficient neutron tagging capabilities. While metallic Gd is insoluble in water, several compounds are very easy to dissolve. Gadolinium sulfate, Gd$_2$(SO$_4$)$_3$, has been thoroughly tested and proposed as the best candidate. Accurate measurement of its concentration, free of doubt from impurities in water, is crucial. An atomic absorption spectrophotometer (AAS) is a device that suits this purpose and is widely used to measure the concentration of many elements. In this study, we describe three different approaches to measure Gd sulfate concentrations in water using an AAS: doping samples with potassium and lanthanum, and employing tantalum and tungsten platforms.