L E T T E R TO THE EDITOR Journal of Radioanalytical and Nuclear Chemistry, VoL 241, No. 2 (1999) 383
Comments on the cross sections of lS6Re in the 186W(p, n) and 186W(d,2n) reactions in connection to the paper given by Z. H. Zhu et al. and correction of the calculated yields of 186Re in the 186W(p,n) reaction N. Shigeta lshioka, 1 T. Sekine, 2 R. M. Lambrecht 3 l Department of Radioisotopes, dapan Atomic Energy Research Institute, 1233 Watanuki, Takasaki, Gunma 370-12, Japan 2 Department of Materials Science, Japan Atomic Energy Research Institute, 1233 Watanuki, Takasaki, Gunma 370-12, Japan s University of Wollongong, Department of Chemistry, Wollongong NSW2522, Australia (Received December 30, 1997)
We enjoyed reading the recent article by ZHU et al. l entitled: "An improved Re/W separation protocol for preparation of carrier-free 186Re.,, The article focuses on a chemical aspect for production of 186Re and proposes an interesting method of radiochemical separation in combination with an unconventional target material. However, we feel obliged to comment on their discussion regarding the cross sections and yields of t86Re in the 186W(p,n) and 186W(d,2n) reactions, since their formulation is erroneous by negating our contribution2 to this journal in 1996. For these reactions, ZHU et al. 1 mention that the 186W(p,n) 186Re reaction is more practical owing to its larger cross section. This statement may mislead one into thinking that the cross sections of the 186W(p,n)186Re reaction are larger than those of the 186W(d,2n)186Re reaction at beam energies practically used for production of this nuclide. Our paper 2 has reported the experimental and the theoretical excitation function of the 186W(p,n) t86Re reaction at proton energies of 5.5-20 MeV. Except for the region near the reaction threshold, the cross sections of this reaction are smaller than those of the 186W(d,2n)186Re reaction measured at deuteron energies of 7-17MeV, which ZHU et al. quoted. The reported cross sections of the 186W(d,2n )186Re reaction, however, have much scattering, so the re-measurement of this excitation function is in progress in our laboratory. Further, it should be mentioned that our experimental data are in good agreement with those of the recent experiment by SZELECSI~NYI et al. 3 SZELECSENYI et al. 3 however, pointed out that our calculation of thick target yields of the reaction is not in agreement with theirs. We checked our calculation, and
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found a mistake in in-put data. Figure 7 in our previous paper 2 should be replaced with Fig. 1 in the present paper. 103
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Fig. 1. Revised thick target yield for the J86W(p,n)186Re reaction
References 1. Z. H. ZHU, X. Y. WANG,Y. H. WU, Y. F. LIU, J. Radioanal. Nucl. Chem., 221 (1997) 199. 2. N. SHIGETA, H. MATSOUKA,A. OSA, M. KOIZUMI, M. [ZUMO, K. KOBAYASHI,K. HASHIMOTO,T. SEKINE, R. M. LAMBRECHT, J. Radioanal. Nucl. Chem., 205 (1996) 85. 3. F. SZELECS'ENY1, S. TAKACS, F. TARKANYI, M. SONCK, A. HERMANNE,Synthesis and Application of lsotopically Labelled Compounds 1997, Wiley, Chichester, 1998, p. 701.
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