Fission Studies with VAMOS and FALSTAFF Spectrometers

by Indu JANGID, 2^d year PhD student at GANIL

The fission process is strongly determined by the both nuclear structure and the nuclear dynamics, which drives the system from its initial state to final break-up through various stages of extreme deformation. The resultant fission fragments, along with the neutron evaporation emerge as promising parameters for elucidating the underlying mechanisms governing the fission process. Currently, at GANIL two experimental setups are in operation for the precise identification of the fission fragments. The FALSTAFF [1-2] spectrometer, employing low-pressure gaseous detectors, is designed to provide constraining data from neutron-induced fission. This setup offers a novel opportunity to identify fission fragments. Conversely, the VAMOS++ [3-4] spectrometer is a large solid-angle, ray-tracing magnetic spectrometer, that benefits from inverse kinematics to provide complete isotopic identification of the fission fragments. An experiment was conducted for the first time at GANIL with VAMOS++ spectrometer in conjunction with FALSTAFF spectrometer — modified for inverse kinematics — to simultaneously measure both fission fragments in coincidence. In this experiment, a ²³⁸U beam at coulomb energies was impinged on a beryllium (Be) target to produce different fissioning systems via fusion and transfer reactions.

In this work, the full isotopic identification of the fission fragments from ²⁴⁷Cm was accomplished. In this seminar, the mass and charge of the fission fragments from both the spectrometer alongside the neutron evaporation will be presented. Additionally, measurements in coincidence from both setup (VAMOS++ and FALSTAFF) in terms of mass and charge will be shown. 

[1] Doré et al., EPJ Web of Conference 42 (2013) 01001.
[2] Doré et al., Nuclear Data Sheets 119 (2014) 346-348.
[3] Rejmund et al., Nucl. Instrum. Methods Phys. Res. A 646 (2011) 184-191.
[4] Pullanhiotan et al., Nucl. Instrum. Methods Phys. Res. A 593 (2008) 343-352.