Comments on “L 2 subshell Coster–Kronig yield at Z=76 and 81”

Abstract

We have analyzed the experimental method used by Simsek [Nucl. Instr. and Meth. B 173 (2001) 269] for determination of the L 2 subshell Coster–Kronig (CK) yield f 23 in 76Os and 81Tl. It involved measurements of the intensities of the L α X-rays excited by the K X-rays of two secondary exciters which were primarily excited by the 59.5 keV γ-rays from the 241Am radioisotope. The first of the secondary exciters chosen was having the energy ( E K p ) of the K p (p=α, β) X-rays such that B L 3 < E K α < B L 2 < E K β < B L 1 and the second was having the energy of the K X-rays such that E K α < B L 3 and B L 3 < E K β < B L 2 , where B L j is the L j subshell ionization threshold for the target element. The f 23 value was deduced from small intensity (∼1%) of the L α X-rays resulting following the L 2–L 3 CK transitions, which was determined by subtracting the intensity of the L α X-rays produced following the direct ionization of the L 3 subshell from the total intensity of the L α X-rays produced in the case of target excitation by the first secondary exciter. It is concluded that the deduced f 23 value must be associated with an enormously large error as compared to the quoted one ∼20%; thus making the measurements inconsequent. An experimental setup with different sets of secondary exciters is being proposed, which is expected to result in the f 23 values with much lesser error.