We present a comparative study of three Monte Carlo simulation frameworks—SRIM, GEANT4, and PHITS—for modeling the transport, stopping, and atomic cascade of negative muons in micrometer-scale, multilayer systems relevant to Muon-Induced X-ray Emission (MIXE) experiments at the Paul Scherrer Institute (PSI). Using a lithium-ion battery as a benchmark target, simulated stopping depth profiles are compared with experimental data from the GIANT spectrometer. All three codes reproduce the overall muon depth distributions with good consistency, even across sharp density contrasts. SRIM provides reliable stopping depth estimates for compact geometries, whereas PHITS reproduces GEANT4 results with comparable accuracy and additionally generates muonic X-ray spectra. These spectra, however, exhibit a systematic energy offset in the K-line transitions of medium- and high-Z elements relative to theoretical and experimental values. Despite this bias, PHITS accurately captures relative intensities and spectral shapes, enabling element-specific line identification. The results demonstrate that SRIM and PHITS constitute practical tools for rapid estimation of muon stopping depth and stopping profiles, and that PHITS holds strong potential for predictive MIXE spectroscopy once its transition-energy bias is corrected. • Benchmarking of GEANT4, PHITS, and SRIM for Muon-Induced X-ray Emission (MIXE) simulations. • Consistent prediction of negative-muon implantation depths in multilayer materials. • Identification of systematic muonic K-line energy shifts in PHITS simulations. • Validation of relative muonic X-ray intensities against experimental battery data. • Practical guidance for simulation-assisted MIXE experiment design.

A new analytical approach has been developed for the collection and subsequent dating of carbonate micro-samples using the U/Th geochronometer. A portable laser ablation system adapted for in-situ collection of laser-induced particles was used to collect micro-samples of speleothems and coral samples. Sample recovery rates ranging from 36% for the most transparent samples to over 90% were measured from mg-sized ablations. After solubilization of the collected samples, uranium and thorium isotopes were quantitatively extracted and preconcentrated using a H 2 DEH[MDP]-based CPE system. Following microinjection analysis and integration of transient signals measured by Q-ICP-MS, U/Th ages were calculated using the IsoplotR geochronology toolbox. Although the results showed an inherently low precision due to reduced sample sizes, the calculated ages were in good agreement with their expected values for most samples, even from the detection of only a few 230 Th ions. The proposed methodology appears to be a promising prospective tool for minimally invasive cave studies that could complement existing approaches. • Minimally invasive sampling approach for the collection of milligram-sized speleothems and coral samples using a custom-built portable laser ablation system. • Particle collection efficiencies ranging from 30% to more than 90% were measured. • Cloud-Point Extraction used for the first time as sample preparation for 230 Th/ 238 U dating of carbonate samples. • Good agreement between calculated and expected ages obtained for most samples, even when only a few 230 Th ions are detected.