Interlaboratory Comparison of Orbitrap Analyzers in OrbiSIMS: Noise Parameters, Intensity Scaling, and Detection Limits

Orbitrap secondary ion mass spectrometry (OrbiSIMS) combines high-resolution mass analysis with surface- and depth-resolved chemical imaging, enabling confident molecular identification across a wide range of materials and biological systems. As the number of OrbiSIMS instruments in operation continues to grow, establishing reproducible and comparable performance across laboratories has become increasingly important. Here, we report the results of a Versailles Project on Advanced Materials and Standards (VAMAS) interlaboratory comparison designed to assess Orbitrap noise characteristics, detection limits, and intensity scale calibration in OrbiSIMS. Using replicated spectra acquired from a common silver reference sample across ten instruments worldwide, we quantify the noise structure of the Orbitrap analyzer and determine scaling parameters that convert arbitrary intensity units into true ion counts. The results confirm that Orbitrap noise behavior is governed by the total ion population in the trap and exhibits consistent characteristics across instruments and Orbitrap models operated below saturation. The ratio between the calibration scaling parameter and the detector noise parameter (A/σ) is shown to be largely intensity-independent in the linear regime, providing a robust metric for comparing instrument performance. From the measured noise properties, detection limits are estimated for each instrument, highlighting the influence of ion load and thresholding on analytical sensitivity. In addition, instrument-specific weighted sum of Rician (WSoR) noise models are derived and shown to yield consistent scaling behavior, enabling noise-unbiased multivariate statistical analysis and machine learning. Together, these results establish a metrological framework for reproducible OrbiSIMS measurements, support meaningful cross-laboratory comparison, and provide a foundation for future studies addressing Orbitrap linearity and performance across the full dynamic range required for advanced SIMS imaging and depth-profiling applications. The concepts and metrics introduced are directly applicable to Orbitrap mass spectrometry more broadly and are a foundation for a robust framework that can be incorporated into QA/QC workflows.