Fragment-LRA angular correlations in thermal neutron induced fission of 235U using a gridded ionisation chamber

The low probability of long range alpha (LRA) emission in fission has been a limitation in the detailed study of this process by the semiconductor detectors where low detection solid angles are involved. In the present work, the possibility of using a back-to-back gridded ionization chamber (2π solid angle) for gragment energy and angle measurements in conjunction with semiconductor detectors for the detection of LRA has been investigated. Fragment-LRA angular correlation for the case of thermal neutron fission of 235U has been measured using this method. The pulses from the collectors and grids of the ionization chamber and the LRA detectors were recorded event by event on a magnetic tape. Grid pulse height distributions in binary and LRA fission were analysed to obtain fragment-LRA angular correlations for different LRA energies. The results are discussed and a point is made that this method can be used with advantage for further detailed studies of LRA fission. (author)