ACCURACY OF PROTON CHARGE DETERMINATION BY AR YIELD MEASUREMENTS AT IN-AIR PIXE

Abstract

Determination of proton charge during in-air PIXE experiments can be hampered when analysing thick non-conductive samples. Several arrangements may be used for overcoming this problem, while in studies of historical documents a variant employing X-ray yield measurements on Ar in air is often used. At compact geometry, with a small distance from the exit foil to the sample (10 mm or less), and also with close location of the X-ray detector to the sample to increase the detector solid angle, the uncertainties in the experimental geometry directly influence the accuracy of the PIXE analysis. The factors affecting the accuracy when using Ar yields are estimated. The advantage of the other technique, measuring X-ray radiation from the exit foil, is elaborated.