Fission fragment angular momentum in ODD-Z fissioning systems

Independent isomeric yield ratios of ¹²⁸Sb, ¹³⁰Sb, ¹³², ¹³¹Te, ¹³³Te, ¹³²I, ¹³⁴I, ¹³⁶I, ¹³⁵Xe and ¹³⁸Cs have been determined in the fast neutron induced fission of ²³⁷Np and ²⁴¹Am using radiochemical and gamma spectrometric technique. From the independent isomeric yield ratios, fragment angular momenta (J_rms) have been deduced using spin-dependent statistical model analysis. Comparison of these data with the literature data for even-Z fissioning systems shows the following important features: (i) Angular momenta for fragments with spherical 82n shell and even-Z products are lower compared to the fragments with out the 82n shell and odd-Z products indicating the effect of nuclear structure. (ii) Angular momentum of even-Z products in all the fissioning systems are comparable where as for odd-Z products it is slightly higher in the odd-Z fissioning systems than in the adjacent even-Z fissioning systems. This indicates the role of single particle on fragment angular momentum in odd-Z fissioning systems. Received: 26 March 1999 / Revised version: 16 October 1999