Development of monoenergetic photon sources in the energy range below 100keV by the X-ray fluorescence method

Abstract

The development of monoenergetic photon source in the energy range below the 100 keV was carried out. The monoenergetic photons are very useful in the calibration of the radiation measuring instruments and can be produced by irradiating the bremsstrahlung X-ray to thin pure metal foils-``Radiators``. The $K_{\alpha}$-fluorescence photons are obtained from the K-shell of the radiator atom with relatively high photon intensity by appropriate filters whose K absorption edge falls on between the energies of the $K_{\alpha}$ and $K_{\beta}$ fluorescence X-ray of the radiator used. These filters reduce the relatively high intensity of fluorescence photons from other shells to the negligible levels. In this experiment, preparation of a component-``Radiator Holder`` and several radiators such as $_{47}Ag,\; _{50}Sn,\; _{64}Gd,\; _{68}Er,\; _{70}Yb$, and $_{82}Pb$ provides the wide monoenergetic photon energy ranging from 20 keV to 80 keV. By the spectrometry of above photon sources with hyperpure Ge low energy photon spectrometry system(LEPS) and multichannel analyzer(MCA), the monochromaticity of the fluorescence X-ray was measured. In this respect, the ``Spectral Purity Factor``, defined as the ratio of the number of $K_{\alpha}$ fluorescence photons emitted from the radiator to the total number of fluorescence photons emitted from the radiator, was carried out. The dosimetry with the 600 cc thin window ionization chamber, which was calibrated by the standard free-air ionization chamber (FAC), was performed. A simple Monte Carlo program simulating the above experimental procedures was also developed for the determination of the optimum experimental conditions.