Nuclear Seminar

Determination of the ²³³Pa(n,f) Reaction Cross-Section by Surrogate Ratio Method

Dr. Basanta Nayak
Bhabha Atomic Research Centre, Mumbai, India
and
University of Notre Dame

Monday, September 22, 2008   4:00 p.m.   NSH 124
(Refreshments served prior to seminar in NSH 124)

Determining neutron induced fission cross sections of short lived actinide nuclei is a major challenge for nuclear physics and nuclear astrophysics. Often indirect method such as surrogate reaction method involving stable target and projectile is employed to estimate the compound nuclear cross sections for short-lived target nuclei. The ²³³Pa(n,f) reaction in Thorium-Uranium fuel cycle is of topical interest in connection with Accelerator Driven Systems (ADS) for nuclear power generation and transmutation of nuclear waste. There are no experimental data available on ²³³Pa(n,f) reaction cross sections above 10.0 MeV neutron energy, which are of importance as nuclear data input for ADS and fast reactor design. In a recent work, we have measured ²³³Pa(n,f) reaction cross-section from 11.5 to 16.5 MeV equivalent neutron energy employing surrogate ratio method, by measuring the ratio of the fission decay probabilities of ²³⁴Pa to those of ²³⁶U compound systems formed respectively in ²³²Th(⁶Li,a)²³⁴ and ²³²Pa and ²³²Th(⁶Li,d)²³⁶U transfer reactions in-situ in the same experiment with overlapping excitation energy. The experiment details and the comparison of the experimental data with predictions of various evaluations will be discussed in the talk.