Program - Brookhaven National Laboratory

they do not satisfy (for example, because of F2 > 0.50) objective criteria. The successful descriptions of
various GDR decay channels were achieved in the frames of various advanced theoretical models (for example,
[3 - 5]). So the new experimentally-theoretical treatment to the evaluation of partial photoneutron
reaction cross sections was proposed [6]. That uses both the results of modern preequilibrium calculations
based on the Fermi-gas densities equations and taking into account the effects of nuclear deformation and
GDR isospin splitting [4, 5] and experimental data for only (γ,xn) reaction cross section, free from outgoing
neutrons multiplicity sorting uncertainties and errors. Theoretically calculated transitional multiplicity
functions Fi theor were used for partial reaction cross section σ eval (γ,in) evaluation of by the way - σ eval (γ,in)
= Fi theor (γ,in) x σ exp (γ,xn). New reliable and authentic data on partial and total photoneutron reaction
((γ,sn) = (γ,n) + (γ,2n) + (γ,3n) + ...) cross sections were evaluated for nuclei mentioned above. It
was shown that those are in contradiction to data obtained using the neutron multiplicity sorting method
but are in agreement with data obtained using the method of induced activity - direct method of partial
reaction cross section determination free of neutron multiplicity problems. Various physical consequences
of ”evaluated-experimental” distinctions of data are discussed. The work was supported by Russia Grant
of Scientific Schools Supporting 02.120.21.485-SS, MINOBRNAUKA Contract 02.740.11.0242 and RFBR
Grant N 09-02-00368.
Corresponding author: V.V.Varlamov
[1] E.Wolynec et al., Revista Brasileira Fisica, 17 56 (1987). [2] V.V.Varlamov et al., INDC(CCP)-
440, IAEA NDS, Vienna, Austria, 37 (2004). [3] M.B.Chadwick et al., Phys.Rev. C44 814 (1991).
[4] B.S.Ishkhanov et al., Physics of Particles and Nuclei, 38 bf232 (2007). [5] B.S.Ishkhanov et al., Physics
of Atomic Nuclei, 71 493 (2008). [6] V.V.Varlamov et al., Bull. Rus. Acad. Sci. Phys. 74 842 (2010).
PR 88
The Systematics of (n,2n) Reaction Excitation Function
Jimin Wang, Xi Tao, Xiaolong Huang, Youxiang Zhuang, China Nuclear Data Center, China Institute of
Atomic Energy, CHINA.
Based on the constant temperature evaporation model taking the competition of (n,3n) reaction and the
contribution of preequilibrium emission into account, the systematics formulae of (n,2n) reaction excitation
function have been established. The systematics behaviours of (n,2n) reaction excitation function have been
studied. There are two systematics parameters T and σn,M, and can be adjusted in the formulae. For
getting the two parameters, the new evaluated data of (n,2n) reactions were adopted and fitted by means
of the nonlinear least squares method. The fitted results agree fairly well with the measured data at
45 < A < 210 below 30 MeV. Based on a body of new measurements, the reliability to predict (n,2n)
reaction excitation function is improved. Hence more accurate systematics prediction for unmeasured
nucleus or energy range may be provided.
PR 89
Analysis of Deuteron Induced Reactions from Threshold
Tao Ye, Weili Sun, Jia Wang, Institute of Applied Physics and Computational Mathematics, Beijing
100094, China. Yukinobu Watanabe, Department of Advanced Energy Engineering Science, Kyushu
University, Kasuga, Fukuoka 816-8580, Japan. Kazuyuki Ogata, Research Center of Nuclear Physics
(RCNP), Osaka University, Ibaraki 567-0047, Japan.
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