Jun 11 – 15, 2018
Villa Monastero
Europe/Zurich timezone

Fission studies using multi-nucleon transfer reactions at the JAEA tandem

Jun 12, 2018, 11:30 AM
30m
Villa Monastero

Villa Monastero

Varenna (Italy)
Fission Fission

Speaker

Prof. Andrei Andreyev (University of York (UK), JAEA (Tokai, Japan))

Description

In this talk we will discuss the use of multi-nucleon transfer (MNT) reactions to study fission properties of a series of exotic nuclei in the neutron-rich actinide region. Most of these nuclei cannot be accessed by the traditional method of complete-fusion reactions. The MNT transfer channels of the $^{18}$O+$^{232}$Th reaction were used to study fission of fourteen nuclei $^{231,232,233,234}$Th, $^{232,233,234,235,236}$Pa, and $^{234,235,236,237,238}$U [1]. 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 (FFMDs) are measured for each transfer channel. In particular, the FFMDs of $^{234}$Th and $^{234,235,236}$Pa were measured for the first time. 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. By using the same method, the measurements with $^{238}$U [2], $^{237}$Np, $^{248}$Cm, and $^{249}$Cf targets were recently performed.
The obtained FFMDs are compared with a calculation based on the fluctuation-dissipation model [2,3], where effect of multi-chance fission (neutron evaporation prior to fission) was considered. It was found that multi-chance fission has significant role on the shape of FFMD, particularly at the high-excitation energies.

Reference
[1] R. Leguillon et al., Phys. Lett. B 761, 125 (2016)
[2] K.Hirose et al., Phys. Rev. Letters, 119, 222501 (2017)
[3] Y. Aritomo and S. Chiba, Phys. Rev. C 88, 044614 (2013)

Primary author

Prof. Andrei Andreyev (University of York (UK), JAEA (Tokai, Japan))

Presentation materials