Small sample measurements at the low energy muon facility of Paul Scherrer Institute

Abstract

The low energy muon spin rotation spectroscopy (LE-$\mu$SR) is primarily used to investigate thin films, surfaces, and interfaces of materials, which has matured at the Paul Scherrer Institute (PSI) and is routinely employed by users of the low energy muon (LEM) facility. However, because of the large beam spot and low implanted muons rate, LE-$\mu$SR measurements on small samples are difficult, requiring an optimal sample size of $25\times25$ mm$^2$. Recently, we have boosted our ability to measure small samples, down to $5\times5$ mm$^2$ area, by beam collimation and tuning. This achievement is crucial for the measurements of many magnetic and superconducting materials. Furthermore, we have devised a method that allows us to measure five small area samples mounted together on the same sample plate. We expect this method to further improve the efficient use of beam time at LEM.