Optical setup for a piston-cylinder type pressure cell: a double-volume approach

TL;DR

This paper introduces a novel optical setup with separate sample and optical volumes for precise in-situ pressure measurement in high-pressure experiments, using optical calibrants for high accuracy.

Contribution

It presents a new double-volume optical setup that enables accurate in-situ pressure calibration without the need for additional calibration steps.

Findings

Pressures in sample and optical volumes are consistent within experimental error.

The setup successfully uses SrB₄O₇:(Sm,Eu) as a calibrant for high-precision pressure measurement.

The method allows for up to eight fluorescence lines for accurate pressure determination.

Abstract

Measurement of the absolute value of the applied pressure in high-pressure muon and neutron experiments is a complicated task. It requires both the presence of a calibration material inside the sample volume as well as additional time for refining the response of the calibrant. Here we describe the use of optical calibrants for precise determination of the pressure value inside the piston-cylinder clamp cells. Utilizing the concept of separate volumes for the sample and the optical media, a new setup for conducting in-situ pressure measurements has been successfully tested. Pressures in both the `sample' and the `optical' volumes were proved to be the same within experimental accuracy. The use of SrB$_{4}$O$_7$:(0.01 Sm$^{2+}$, 0.03 Eu$^{2+}$) as a pressure calibrant allows for a high accuracy of pressure determination by considering up to eight fluorescence lines.