The R package (doi:10.1021/acs.jproteome.0c00866) provides an interface for Thermo Fisher Scientific raw files branched from rawDiag (doi:10.1021/acs.jproteome.8b00173). This package wraps the functionality of the RawFileReader .NET assembly. Within the R environment, spectra and chromatograms are represented by S3 objects.