Activities observed in iridium after neutron bombardment. Remarks on a paper by H. H. Hennies and A. Flammersfeld
Recently Hennies and Flanunersfeld (Naturwissenschaften, 47: 11(1960)) reported ths observation of a new 47-sec activity produced by irradiating Ir powder with slowed-down neutrons. The activity was tentatively assigned to Ir/ sup 194//sup m/. Beta activities, previously ascribed to Ir/sup 192//sup m/, were reassigned to Ir/sup 194//sup m/. A repetition of the experiment on the bombardment of Ir/sup 193/ with slow neutrons (Phys. Rev. Lettens, 3: 4S(1959)) confirmed the previous conclusions and ruled out a 47-sec period in Ir/sup 192/ or Ir/sup 19 / 4>s. It was suggested that the Hennies and Flammersfeld results may be partly ascribed to a Rh impurity and partly to the effect of fast neutrons. (J.S.R.)
Mise en évidence de quelques nouveaux états isomériques
The half lives and gamma energies of isomeric states of In/sup 114/, Ir/sup 194/, hf/sup 178/, ga/sup 72/, Ba/sup 135/, N a/sup 24/, Yb/sup 175, and Yb/sup 177 were determined and the results are tabulated. To distinguish the (n, gamma ) reactions from other possible reactions, each irradiation was made with and without Cd shielding. The isomeric level of As/sup 75m/ was detected, which indicates that its limit of sensitivity is aporoximately 15 msec. The In/ sup 114m isomer with T/sub 1/2 = 0.042 sec was not detected but another isomeric state was found. (J.S.R.)
Prediction of net pressure on pressure equalized cavities
Abstract A numerical model has been developed for prediction of net pressure on pressure equalized cavities. The results based on this model show good agreement with those obtained from mock-up tests. Parametric studies verify that reductions in cladding load are possible, with proper design of curtain walls.