Essentially all X-ray measurements are made by
photon counting techniques but the results are seldom converted to
radiant flux or
irradiance or
radiant exposure. The term
photon flux would be appropriate if the measurements were corrected for detector efficiency but
this is seldom done for X-ray chemical analysis. Therefore the term X-ray intensity,
, is commonly used and expressed as photons/unit time detected. Likewise the term relative
X-ray intensity,
,
is used to mean the intensity for the analyte in an unknown specimen divided by the
intensity for a known concentration of the analyte element.
Source:
PAC, 1980, 52, 2541
(Nomenclature, symbols, units and their usage in spectrochemical analysis - IV X-ray
emission spectroscopy)
on page 2544