Experimental studies of fission mechanism

The multi-nucleon transfer reaction (MNT) is a powerful tool to populate a variety of nuclides with a wide range of excitation energy. At the JAEA Tokai tandem accelerator facility, we have been studying fission mechanism through fission observables such as fission-fragment mass distributions, fission probabilities, prompt-fission neutrons, and so on.

The MNT reaction is also expected one of viable reactions to produce super-heavy nuclei with more neutrons [1]. The angular momentum transferred in the MNT reaction is an important property since it influences a survival probability of a compound nucleus. In the present study, the angular momentum transferred in MNT reactions are experimentally deduced using fission. In MNT reactions, the axis of the angular-momentum transfer can be defined as perpendicular to the reaction plane. The fission-fragment angular distribution measured with respect to this axis, thus, strongly reflects the angular momentum. We performed measurements of the fission-fragment angular distribution in the ¹⁸O+²³⁷Np reaction, and deduced the angular momenta transferred to the produced compound nuclei of ^236-240Np, ^237-242Pu, ^238-245Am, ^243-245Cm.

In this workshop, details of the experiment and results will be presented as well as other experimental activities.

[1] V.I. Zagrebaev and W. Greiner, Phys. Rev. C87, 034608 (2013).