Photon‐excited K X‐ray fluorescence cross‐section measurements for some low‐Z‐elements

X-ray fluorescence cross-section for Kα x-ray lines were measured for the light elements Na, Mg, Al, Si, S, Cl and K relative to Ca at a photon excitation energy of 5.97 keV (Mn K x-ray). A windowless retractable Kevex Si(Li) detector system having an energy resolution of 146 eV at 6.4 keV was used for the detection of the characteristic K x-rays. The measurements were performed in a vacuum chamber maintained at a pressure of ca 10−7 Torr using a 55Fe radioactive excitation source and targets of ultra-pure elements/compounds of the above-mentioned elements. Cross-sections were also calculated using photoelectric cross-sections, fluorescence yields and the fractional x-ray emission rates. Measured and calculated x-ray fluorescence cross-sections agreed within reasonable limits.