Tuesday, August 29, 2017 - 14:00
30 BB 03
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Open to: Staff
Speaker: Agnieszka Czeszumska (Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, USA, Department of Nuclear Engineering, University of California, Berkeley, California 94720, USA)
For decays where β− decay populates excitation energies above the neutron separation energy, the daughter nucleus may de-¬‐excite by emitting a neutron, a process referred to as β-¬‐delayed neutron emission (βn).
This decay mode influences abundances calculated in r-¬‐process nucleosynthesis models, affects nuclear reactor safety analysis calculations, and can illuminate aspects of nuclear structure. However, existing data for neutron-¬‐rich nuclei are often incomplete or discrepant. A newly developed recoil-¬‐ion detection technique allows for high-¬‐precision βn branching ratio and neutron energy measurements, without the difficulties associated with direct neutron detection. In this approach, ions are trapped using a Beta-¬‐Paul trap surrounded by an array of detectors. Upon decay, recoiling daughter nuclei and emitted particles emerge from the center of the trap with minimal scattering. The neutron energy can be determined from the time-¬‐of-¬‐flight, and hence momentum, of the recoiling ions. In this talk, I will summarize the latest results from the experiment conducted at CARIBU.
This material is based upon work supported by the Department of Energy, National Nuclear Security Administration, under Award Numbers DE-¬‐NA0000979 (NSSC),
DE-¬‐AC52-¬‐07NA27344 (LLNL); Office of Nuclear Physics Contract DE-¬‐AC02-¬‐
06CH11357 (ANL), and grants DE-¬‐FG02-¬‐94ER40834 (University of Maryland), DE-¬‐FG02-¬‐98ER41086 (Northwestern University); NSERC, Canada, under Application No. 216974; and the Department of Homeland Security. A. Czeszumska acknowledges support from the Lawrence Scholar Program at LLNL.