K Fluorescence Yield of Several Metals

The K fluorescence yield (wK) of iron, nickel, copper, and zinc has been measured by the solid angle method. By varying the solid angle subtended by a sample foil at a NaI(Tl) crystal one can distinguish between the collimated primary beam and the isotropically emitted fluorescent x-rays. The following new values were obtained: iron -0.308±{}0.015, nickel -0.366±{}0.011, copper -0.410±{}0.012, and zinc -0.446±{}0.012. In addition, the values for the K fluorescence yield of zirconium, niobium, molybdenum, rhodium, palladium, silver, cadmium, and tin reported earlier, have been redetermined. With the single exception of the value for zirconium, these new values agree quite closely with the earlier values. The average change is approximately 1% or about one third of the previously estimated error. The redetermined values of wK are as follows: Zr -0.70±{}0.02, Nb -0.73±{}0.02, Mo -0.73±{}0.02, Rh -0.786±{}0.015, Pd -0.790±{}0.015, Ag -0.821±{}0.019, Cd -0.827±{}0.015, Sn -0.846±{}0.012. A phosphorescence of the NaI(Tl) crystals with a decay time of 8±{}2 milliseconds was found, while no sign of a reported 0.2-millisecond decay was observed.