| Experiments at CERN | |
| Title | Identification and systematical studies of the electron-capture delayed fission (ECDF) in the lead region |
| Author(s) | Venhart, M ; Pauwels, D B ; Lane, J |
| Experiment | IS466 |
| Greybook | See IS466 experiment |
| Approved | 27 February 2008 |
| Status | Finished |
| Collaboration | ISOLDE |
| Accelerator | CERN ISOLDE |
| Abstract | In our recent experiment (March 2007) at the velocity filter SHIP(GSI) we observed the electron-capture delayed fission of the odd-odd isotope $^{194}$At. This is the first unambiguous identification of this phenomenon in the very neutron-deficient nuclei in the vicinity of the proton shell closure at Z=82. In addition, the total kinetic energy (TKE) for the daughter nuclide $^{194}$Po was measured, despite the fact that this isotope does not decay via spontaneous fission. Semi-empirical analysis of the electron-capture Q$_{EC}$ values and fission barriers B$_{f}$ shows that a relatively broad island of ECDF must exist in this region of the Nuclide Chart, with some of the nuclei having unusually high ECDF probabilities. Therefore, this Proposal is intended to initiate the systematic identification and study of $\beta$-delayed fission at ISOLDE in the very neutron-deficient lead region. Our aim is to provide unique low-energy fission data (e.g. probabilities, TKE release, fission barriers and their isospin dependence, mass/charge distribution of fragments, neutron and $\gamma$ multiplicities) for the region of the nuclei, which do not decay by spontaneous fission. More generally, the $\beta$-delayed fission is believed to play an important role in the r-process (e.g. production of heavy elements, termination of the r-process, "fission recycling". As a first step in the program we propose to study $^{178,180}$Tl and $^{200,202}$Fr isotopes, for which ISOLDE can provide pure beams with the intensities not accessible anywhere else. |
| Related document(s) | CERN-INTC-2008-001 (INTC-P-235) |
Record created 2008-04-01, last modified 2022-03-01