Number of particles transmitted by the analyser divided by the number of such particles per solid angle and per interval of the dispersing parameter (e.g. energy, mass, or wavelength) available for measurement as a function of the dispersing parameter.
See also: spectrometer response function
Source:
PAC, 2020, 92, 1781. 'Glossary of methods and terms used in surface chemical analysis (IUPAC Recommendations 2020)' on page 1813 (https://doi.org/10.1515/pac-2019-0404)