RESONANT EXCITATION OF THE REACTION TA-180(M)(GAMMA,GAMMA')TA-180 - COMMENT

We point out that the large integral cross section values reported for the Ta-180(m)(gamma, gamma')Ta-180 reaction by Collins et al. correspond to transition strengths exceeding the recommended upper limits. The small overall cross section ratio of the aforementioned and the In-114(gamma, gamma')In-115(m) reactions is shown to be an indirect piece, of evidence against the enormous integral cross sections. Collins et al. used the Sr-87(gamma, gamma')Sr-87(m) reaction to verify their calculated photon flux, but did not identify the observed activation levels. We identify four photoactivation levels of Sr-87 at 1228.42 keV, 5/2+, 1770.46 keV, 5/2+, 1919.9 keV, 7/2+, 2706.5 keV, 9/2 +, and deduce the existence of (at least) a further one around 2.6 MeV. These new data suggest that the calculated photon flux used by Collins et al. should be rechecked.