[Triumf-seminars] TRIUMF Nuclear Physics Seminar today at 15:30

[TRIUMF Seminars]

Date/Time: Mon 2016-01-11 at 15:30

Location:  Auditorium          

Speaker:   Michael Bowry (TRIUMF)

Title:     Abrasion-Fission Reactions at Intermediate Energies

Abstract: Abrasion fission reactions at intermediate energies
Michael Bowry
Three quarters of a century after the first observation of uranium fission via bombardment with neutrons, fission decay continues to serve as a powerful tool for nuclear science. In-flight fission of 0.3-1.0 GeV A uranium beams at GSI Helmholtz Center for Heavy Ion Research [1] and RIKEN Radioactive Isotope Beam Factory [2] have proven effective at producing neutron-rich nuclei and the measurement of cross-sections has provided a valuable benchmark for theoretical fission models. The yield of fission products of a given N and Z was found to be naturally attuned to the N, Z and excitation energy of the projectile prefragments formed in peripheral nuclear collisions. Similar measurements at intermediate energies (< 0.1 GeV A) are scarce despite the potential proximity to the threshold of limiting fragmentation proposed by Benecke et al. [3] (projectile energy-independence of cross section) and may provide a sensitive probe of prefragment formation. Cross section measurements spanning 20 different isotopic chains from nickel to silver are presented following in-flight fission reactions of a 80 MeV A uranium-238 beam on a diamond active target at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (East Lansing, USA). Fission products were identified on an event-by-event basis by correlating time-of-flight and energy-loss measurements in the S800 spectrograph with in-flight gamma-decays reconstructed by the Gamma-Ray Energy Tracking Array (GRETINA) in the rest frame of the projectile. Transmission through the S800 has been determined using state-of-the-art simulations developed in the LISE++ code [4].

[1] M. Bernas et al., Nucl. Phys. A 725, 213 (2003) 
[2] H. Suzuki et al., Nucl. Instr. Meth. Phys. Res. B 317, 756 (2013) 
[3] J. Benecke et al., Phys. Rev. 188, 2159 (1969)
[4] O. B. Tarasov and D. Bazin, Nucl. Instr. Meth. Phys. Res. B 266, 4657 (2008)



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