K-shell fluorescence yields of medium and heavy elements using a simple method

Abstract

K-shell fluorescence yields, ω K , of medium and heavy elements in the atomic number range 62 ≤ Z ≤ 83 at incident photon energies of 123.6 and 320 keV were measured by adopting the simple method proposed earlier, using an NaI(Tl) detector coupled to an active filter amplifier and a 1K multi-channel analyser. The intensities were measured by placing the source and the target right on the face of the detector and by employing very weak radioactive sources ( 57 Co and 51 Cr) of the order of 10 4 Bq. Measured values were compared with the recent standard fitted values of Hubbell et al., and were found to be in close agreement. The ω K values of bismuth, gold, tungsten, gadolinium and samarium were measured for the first time.