Precision measurement of X-ray line spectra by energy dispersion in a gas microstrip detector

It is shown that when a gas microstrip detector (GMSD) is operated in such a way as to gain freedom from detector wall effects, the response of the detector to an X-ray line is stable and can be fitted reliably with a lognormal (LN) distribution function. The LN function permits the fitting of adjacent, overlapping X-ray lines with an accuracy in position of a few eV with an attendant penalty in the statistics required for a given precision in the amplitude measurement. Experimental data and Monte Carlo simulation data are presented to indicate the possible range of usefulness of this technique for energy-dependent X-ray line spectroscopy in applications (such as X-ray fluorescence analysis). The usefulness of the LN fits for detector studies is also noted.