Comments on "L2 subshell Coster-Kronig yield at Z=76 and 81"

We have analyzed the experimental method used by Simsek [Nucl, Instr. and Meth, B 173 (2001) 269] for determination of the L, subshell Coster-Kronig (CK) yield f(23) in Os-76 and Tl-81. It involved measurements of the intensities of the L, X-rays excited by the K X-rays of two secondary exciters which were primarily excited by the 59.5 keV gamma -rays from the Am-241 radioisotope. The first of the secondary exciters chosen was having the energy (E-Kp) of the K-P (p = alpha, beta) X-rays such that B-L3 < E-K alpha < B-L2 < E-K beta < B-L1 and the second was having the energy of the K X-rays such that E-K alpha < B-L3 and B-L3 < E-K beta < B-L2, where B-L alpha is the L-f subshell ionization threshold for the target element. The f(23) value was deduced from small intensity (similar to1%) of the L-alpha X-rays resulting following the L-2-L-3 CK transitions, which was determined by subtracting the intensity of the L-alpha X-rays produced following the direct ionization of the L-3 subshell from the total intensity of the L-alpha 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 similar to 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. (C) 2001 Elsevier Science B.V. All rights reserved.