ANISOTROPY OF FISSION ANGULAR DISTRIBUTIONS FOR 16O + 192Os AND 197Au


M. Ogihara, S.C. Jeong, H. Fujiwara, M. Miyazawa, Y.H. Pu, W. Galster, Y. Nagashima, S.M. Lee, T. Mikumo

Institute of Physics and Tandem Accelerator Center
University of Tsukuba, Ibaraki 305, Japan

H. Ikezoe, K. Ideno, Y. Tomita, Y. Sugiyama

Japan Atomic Energy Research Institute
Tokai, Ibaraki-ken 319-11, Japan

T. Matsuse

Faculty of Textile Science and Technology
Shinshu University, Nagano 386, Japan

In this article we give an answer to the question whether fission angular distributions are determined at the saddle point or at the scission point. We measured precisely fission angular distributions for 16O-induced fission at various projectile energies. We analyzed the data in terms of the statistical model of Ericson. Through the analysis we conclude that the fission angular distribution is determined at the scission point. From this standpoint, we deduced the average channel spin of fission fragments from the fission angular distributions giving a good agreement with the results obtained by γ-ray multiplicities.

KEYWORDS: fission angular distribution, saddle point, scission point, statistical model of Ericson, decoupling angle, average channel spin