Experimental fission study using multi-nucleon transfer reactions

K Nishio ,Shouya Tanaka,Satoshi Chiba,T Ohtsuki ,K Hirose ,J Smallcombe ,C M Petrache ,I Tsekhanovich ,Y Aritomo ,R Orlandi ,K Tsukada ,R Léguillon ,H Makii ,A N Andreyev

doi:10.1051/epjconf/201714604009

Abstract

It is shown that the multi-nucleon transfer reactions is a powerful tool to study fission of exotic neutron-rich actinide nuclei, which cannot be accessed by particle-capture or heavy-ion fusion reactions. In this work, multi-nucleon transfer channels of the reactions of 18 O+232 Th, 18 O+238 U and 18 O+248 Cm are used to study fission for various nuclei from many excited states. Identification of fissioning nuclei and of their excitation energy is performed on an event-by-event basis, through the measurement of outgoing ejectile particle in coincidence with fission fragments. Fission fragment mass distributions are measured for each transfer channel. Predominantly asymmetric fission is observed at low excitation energies for all studied cases, with a gradual increase of the symmetric mode towards higher excitation energy. The experimental distributions are found to be in general agreement with predictions of the fluctuation-dissipation model. Role of multi-chance fission in fission fragment mass distributions is discussed, where it is shown that mass-asymmetric structure remaining at high excitation energies originates from low-excited nuclei by evaporation of neutrons.

Highlights

Multi-nucleon transfer (MNT) reactions is another unique reaction which allow us to populate neutronrich nuclei which cannot be accessed by other reactions such as particle capture and/or heavy-ion fusion reactions
At the tandem accelerator facility of the Japan Atomic Energy Agency (JAEA), we studied the MNT channels of c The Authors, published by EDP Sciences
The result demonstrates that 18Oinduced neutron-transfer reaction can be a surrogate of neutron-induced fission to give Fission-fragment mass distributions (FFMDs)

Summary

Introduction

Multi-nucleon transfer (MNT) reactions is another unique reaction which allow us to populate neutronrich nuclei which cannot be accessed by other reactions such as particle capture and/or heavy-ion fusion reactions. An inverse kinematics technique was used in the MNT channels of the 238U+12C reaction, to study fusion-fission of excited transactinide nuclei with the help of the large-acceptance magnetic spectrometer VAMOS@GANIL [7,8,9]. In these experiments, sufficiently-high A and Z resolution for FFs was achieved due to their kinematic boost, allowing the simultaneous measurement of the complete mass- and atomic-number distributions of fission fragments

Methods

Results

Conclusion