New Frontiers in Muon-Spin Spectroscopy Using Si-Pixel Detectors
Abstract
The study of novel quantum materials relies on muon-spin rotation, relaxation, or resonance (\mSR) measurements. Yet, a fundamental limitation persists: many of these materials can only be synthesized in extremely small quantities, often at sub-millimeter scales. While \mSR ~offers unique insights into electronic and magnetic properties, existing spectrometers lack a sub-millimeter spatial resolution and the possibility of triggerless pump-probe data acquisition, which would enable more advanced measurements. The General Purpose Surface-muon instrument (GPS) at the Paul Scherrer Institute (PSI) is currently limited to a muon stopping rate of \SI{40}{\kilo\hertz} to \SI{120}{\kilo\hertz}, a constraint that will become more pressing with the upcoming High-Intensity Muon Beam (HIMB) project. To overcome these challenges, we demonstrate the feasibility of employing ultra-thin monolithic Si-pixel detectors to reconstruct the stopping position of muons within the sample, thereby significantly enhancing the capability of measuring at higher muon rate. Additionally, we explore the first steps toward a triggerless pump-probe \mSR ~measurement scheme. Unlike conventional pump-probe techniques that require external triggers, a triggerless readout system can continuously integrate stimuli pulses into the data stream, allowing real-time tracking of ultra-fast dynamics in quantum materials. This approach will enable the study of transient states, spin dynamics, and quantum coherence under external stimuli.
Cite
@article{arxiv.2504.12993,
title = {New Frontiers in Muon-Spin Spectroscopy Using Si-Pixel Detectors},
author = {Heiko Augustin and Niklaus Berger and Andrin Doll and Pascal Isenring and Marius Köppel and Jonas A. Krieger and Hubertus Luetkens and Lukas Mandok and Thomas Prokscha and Thomas Rudzki and André Schöning and Zaher Salman},
journal= {arXiv preprint arXiv:2504.12993},
year = {2025}
}