TRIM Simulations Tool for $\mu^+$ Stopping Fraction in Hydrostatic Pressure Cells

TL;DR

This paper introduces a user-friendly simulation tool based on TRIM simulations to estimate muon stopping fractions in pressure cells for $$SR experiments, aiding experimental planning and data analysis.

Contribution

It presents a practical GUI tool utilizing pySRIM and TRIM simulations to accurately estimate muon stopping fractions in pressure cell setups for $$SR experiments, addressing background signal issues.

Findings

The tool effectively predicts muon stopping distributions in pressure cells and samples.

It helps optimize experimental parameters to reduce background signals.

The GUI makes the simulation accessible for experimental planning.

Abstract

For quantum systems or materials, a common procedure for probing their behaviour is to tune electronic/magnetic properties using external parameters, e.g. temperature, magnetic field or pressure. Pressure application as an external stimuli is a widely used tool, where the sample in question is inserted into a pressure cell providing a hydrostatic pressure condition. Such device causes some practical problems when using in Muon Spin Rotation/Relaxation ($\mu^+$SR) experiments as a large proportion of the muons will be implanted in the pressure cell rather than in the sample, resulting in a higher background signal. This issue gets further amplified when the temperature dependent response from the sample is much smaller than that of the pressure cell,which may cause the sample response to be lost in the background and cause difficulties in aligning the sample within the beam. To tackle this issue, we have used pySRIM to construct a practical and helpful simulation tool for calculating muon stopping fractions, specifically for the pressure cell setup at the $\mu$E1 beamline using the GPD spectrometer at the Paul Scherrer Institute, with the use of TRIM simulations. The program is used to estimate the number of muon stopping in both the sample and the pressure cell at a given momentum. The simulation tool is programmed into a GUI, making it accessible to user to approximate prior to their experiments at GPD what fractions will belong to the sample and the pressure cell in their fitting procedure.