A SYSTEM FOR THE INTENSITY CALIBRATION OF ELECTRON SPECTROMETERS

A system for the calibration of the intensity/energy response function for electron spectrometers used in Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) is described. The basic physical principles of a complete system are detailed to show how the data are derived and how the calibrations may be made traceable to the SI system. The calibration method gives an accurate energy dependence of the intensity/energy response function which is the functional dependence presently needed for analytical work. For AES this gives a reproducibility demonstrated below 2% and for XPS at 4%. For AES this is also made traceable in an absolute sense, where the response function is given in sr eV units, to an accuracy of 6%. For XPS the units of the response function are also sr eV for focused X-ray monochromators but for diffuse unmonochromated X-ray sources m(2) sr eV units are more appropriate. Accurate traceability for XPS exists for all terms except the X-ray source production efficiency. The full traceability is important for those studying absolute cross sections but is usually unimportant where quantification procedures involve any normalisation procedures.