Excitation functions of natZn(p,x) nuclear reactions with proton beam energy below 18 MeV
Journal Article
·
· Applied Radiation and Isotopes
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE SC OFFICE OF NUCLEAR PHYSICS
- DOE Contract Number:
- DE-SC00112704
- OSTI ID:
- 1174103
- Report Number(s):
- BNL-107454-2015-JA; R&D Project: KBCH139; 18086; KB0202011
- Journal Information:
- Applied Radiation and Isotopes, Vol. 94
- Country of Publication:
- United States
- Language:
- English
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Most theoretical approaches used in nuclear astrophysics to model the nucleosynthesis of heavy elements incorporate the so-called statistical model in order to describe the excitation and decay properties of atomic nuclei. One of the basic assumptions of this model is the validity of the Brink–Axel hypothesis and the related concept of so-called photon strength functions to describe γ-ray transition probabilities. We present a novel experimental approach that allows for the first time to experimentally determine the photon strength function simultaneously in two independent ways by a unique combination of quasi-monochromatic photon beams and a newly implemented γ–γ coincidence setup. This technique does not assume a priori the validity of the Brink–Axel hypothesis and sets a benchmark in terms of the detection sensitivity for measuring decay properties of photo-excited states below the neutron separation energy. The data for the spherical off-shell nucleus 128Te were obtained for γ-ray beam-energy settings between 3 MeV and 9 MeV in steps of 130 keV for the lower beam energies and in steps of up to 280 keV for the highest beam settings. We present a quantitative analysis on the consistency of the derived photon strength function with the Brink–Axel hypothesis. The data clearly demonstrate a discrepancy of up to a factor of two between the photon strength functions extracted from the photoabsorption and photon emission process, respectively. In addition, we observe that the photon strength functions are not independent of the excitation energy, as usually assumed. Thus, we conclude, that the Brink–Axel hypothesis is not strictly fulfilled in the excitation-energy region below the neutron separation threshold (Sn = 8.78 MeV) for the studied case of 128Te.
Excitation function for the reaction $sup 12$C(n,p)$sup 12$B at neutron energies of 16 to 18 MeV
Proton scattering from an excited nucleus ([sup 18][ital F][sup [ital m]],[ital J][sup [pi]]=5[sup +],[ital E][sub [ital x]]=1. 1 MeV) using a [gamma]-ray-tagged secondary isomeric nuclear beam
Journal Article
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Tue Jan 01 00:00:00 EST 2019
· Physics Letters B
·
OSTI ID:1174103
+10 more
Excitation function for the reaction $sup 12$C(n,p)$sup 12$B at neutron energies of 16 to 18 MeV
Journal Article
·
Fri Dec 01 00:00:00 EST 1972
· Izv. Akad. Nauk SSSR, Ser. Fiz., v. 36, no. 12, pp. 2621-2622
·
OSTI ID:1174103
+3 more
Proton scattering from an excited nucleus ([sup 18][ital F][sup [ital m]],[ital J][sup [pi]]=5[sup +],[ital E][sub [ital x]]=1. 1 MeV) using a [gamma]-ray-tagged secondary isomeric nuclear beam
Journal Article
·
Wed Mar 01 00:00:00 EST 1995
· Physical Review, C (Nuclear Physics); (United States)
·
OSTI ID:1174103
+6 more