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ABSTRACT: The 57Fe(p,γ)58Co reaction has been investigated in the proton energy region Ep = 1 580-2 125 keV. Branching ratios for low lying levels and decay schemes for seven resonances have been investigated, and possible analogue states or fragments of analogue states of the 2 782 keV (1+) and 2 876 keV (2+) levels in 58Fe have been suggested. The investigated analogue states give a Coulomb displacement energy of 8 846 ± 20 keV.
Physica Scripta 01/2007; 12(1-2):95. · 1.20 Impact Factor
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ABSTRACT: The decay of the metastable state in 84Rb has been studied by means of the 85Rb(n, 2n)84Rb and the 85Rb(γ, n)84Rb reactions. A possible but very weak feeding of excited states in 84Kr directly from the metastable state is suggested. The cross sections for the (n, 2n), (n, p) and (n, α) reactions of the target nuclei 85Rb and 87Rb were measured by the activation method with 14.8 MeV neutrons.
Physica Scripta 01/2007; 19(3):251. · 1.20 Impact Factor
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ABSTRACT: The gamma decays following the 63Cu(p, γ)64Zn and 65Cu(p, γ)66Zn reactions have been studied with Ge (Li) spectrometers. Proton energies of about 2 MeV have been used. Level schemes up to about 4 MeV for 64Zn and 66Zn have been constructed from the data.
Physica Scripta 01/2007; 22(5):432. · 1.20 Impact Factor
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ABSTRACT: Unbound 1p1h states are excited together with the bound ones in one-step direct processes induced by nucleons of energy greater than the particle binding energy. The cross-sections of the one-step direct reactions to bound final states are folded into a convolution integral to obtain the multistep cross-sections. This is done in the framework of the theory of Feshbach, Kerman and Koonin (FKK) that describes the emission of one particle. The processes to unbound 1p1h final states give rise to more complicated direct reactions, that are evaluated by an approximate method. The comparison of the theory with inclusive proton inelastic scattering by iron and with the charge exchange (p,n) reaction on zirconium is revised, at energies from 25 MeV to 120 MeV. It is shown that in the case of the (p,n) reaction the theory of FKK does not account for approximately 35% of the direct processes.
European Physical Journal A 07/2004; 21(2):287-292. · 2.19 Impact Factor
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ABSTRACT: The cross sections for neutron inelastic scattering by niobium at 20 MeV and for the charge-exchange (p,n) reaction on copper at 27 MeV have been calculated using the multistep direct reaction theory of Feshbach, Kerman and Koonin [1]. The theory was modified to include the non-DWBA matrix elements and the collective vibrations. The results show enhanced contributions from two-, three- and four-step direct reactions in agreement with experiment.
Acta Physica Hungarica 01/2002; 16(1):35-44.
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ABSTRACT: Cross sections for the (p,xn) reactions for proton energies from 9 to 27 MeV on targets from titanium to thulium are consistently explained by statistical direct reactions accompanied by gradual absorption of protons into successive compound states of increasing complexity which evolve towards the compound nucleus. It is shown that, in the absence of strong collective excitations, pre-equilibrium compound reactions prevail over direct processes. Physical parameters of the multistep direct reaction model are obtained, which when applied in analyses of (n,xn) data may reveal the extent of collective enhancement of the scattering cross section.
Journal of Physics G Nuclear and Particle Physics 12/1998; 21(8):1089. · 4.18 Impact Factor
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ABSTRACT: The multistep reaction theory of Feshbach, Kerman and Koonin is used to analyse data on nuclear reactions to the continuum. The multistep direct, multistep compound, collective and compound nucleus cross sections are calculated with the same set of parameters and it is found that it is possible to fit the , and data in a fully consistent way. The data, however, could only be fitted by approximately doubling the strength of the effective interaction. Several possible reasons for this were investigated including isospin effects, neutron - proton distinguishability, sensitivity to optical potentials and non-locality effects, but the difficulty still remains.
Journal of Physics G Nuclear and Particle Physics 12/1998; 22(5):629. · 4.18 Impact Factor
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ABSTRACT: Angular distributions have been measured for the elastic and inelastic scattering of protons from magnesium isotopes at the proton energy Ep=9.1 MeV. Optical-model parameter searches yielded potential parameters used in the total Hauser-Feshbach and DWBA calculations. The ratios of the total experimental to the total Hauser-Feshbach inelastic cross sections for different states of 25Mg and 26Mg are found to lie in relatively narrow bands around the average values. A significant enhancement of these ratios with respect to the average values is observed only for the first excited members of the ground-state rotational bands of these nuclei. The enhancement is attributed to direct rotational excitation. The deformation parameters for these states are extracted with the aid of DWBA and are compared with those previously established.
Journal of Physics G Nuclear Physics 12/1998; 2(11):831.
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ABSTRACT: The (n, 2n) reaction cross sections on 134Ba, 142Nd, 150Nd and 144Sm have been measured by the activation method. The results are compared with the calculations accounting for nucleon evaporation and pre-equilibrium emission.
Journal of Physics G Nuclear Physics 12/1998; 10(1):91.
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ABSTRACT: Pre-equilibrium neutron emission includes substantial collective excitations in the continuum region that add to the multistep direct and multistep compound reactions. These collective reactions are investigated for the strongly-deformed, rotational tungsten nucleus. The collective cross sections are calculated using the macroscopic model. The results describe the neutron emission cross sections measured at 14.1 MeV and 26 MeV incident neutron energy.
Journal of Physics G Nuclear and Particle Physics 12/1998; 22(8):1219. · 4.18 Impact Factor
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ABSTRACT: Cross sections for the (n, p) reaction on64,66,67,68Zn isotopes have been measured by the activation method and successfully described in terms of the statistical multistep direct and the novel statistical multistep compound reaction model.
Zeitschrift für Physik A Hadrons and Nuclei 05/1995; 352(2):137-143.
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ABSTRACT: Cross sections for70,72,73,74Ge(n, p)70,72,73,74Ga,70Ge(n, 2n)69Ge,72Ge (n,)69Zn
m
and74Ge(n, )71Zn
m
reactions are measured in the energy range from 13.0 to 16.6 MeV by the activation method using Ge(Li) detector-ray spectroscopy and compared with predictions of the reaction model incorporating preequilibrium and equilibrium emission mechanisms to interpret the energy dependence of the isotopic effect occuring in the (n, p) reaction. The fitted single-particle state-density parametersg, determined here for the germaniums are discussed together with theg-values found previously for the Se, Zr and Pd isotopic chains. A validity of the consistency condition between the precompound and compound models, which relatesg to the experimental level-density parametera viaa=
2
g/6 is demonstrated.
Zeitschrift für Physik A Hadrons and Nuclei 01/1992; 342(3):283-290.
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ABSTRACT: Cross sections for74, 76, 77, 78Se(n, p)74, 76, 77, 78As,76,Se(n,2n)75Se and80Se(n, )77,Ge reactions have been measured in the energy range from 13.0 to 16.6 MeV by the activation technique using Ge(Li) detector-ray spectroscopy. Samples of selenium of natural isotopic composition were used as targets. The measurements provide information on the evolution of the (n, p) excitation functions with the increasing target neutron number (isotopic effect). The reaction model combining the compound nucleus and the preequilibrium emission processes is used to interpret these three types of reactions. The isotopic trend for the (n, p) reactions due to the neutron-proton competition in the compound nucleus is satisfactorily reproduced. However, a further experimental and theoretical work is needed for a better understanding of the origins of discrepancies which are suggested to be related to the precompound aspects of the assumed reaction model.
Zeitschrift für Physik A Hadrons and Nuclei 08/1989; 334(3):285-291.
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ABSTRACT: Cross sections of (n, p), (n, ), and (n, 2n) reactions on molybdenum isotopes have been measured, in the neutron energy range from 13 MeV to 17 MeV, and interpreted in terms of evaporation from the compound nucleus and preequilibrium emission.
Zeitschrift für Physik A Hadrons and Nuclei 01/1986; 323(1):91-96.
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Computer Physics Communications 09/1984; 33:373-398. · 3.27 Impact Factor
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ABSTRACT: The64Ni(p, )65Cu reaction has been studied in the proton energy rangeE
p
=2.05–2.55 MeV. The gamma-ray spectra were recorded with a three-crystal pair spectrometer at proton energy differences of 19 keV covering the proton energy range. An average gamma-ray spectrum was formed by adding all the individual spectra after proper adjustment as a result of the alterations in proton energy. The intensities of the gamma rays to final states with knownJ
-values were tested against theoretical calculations based on the Hauser-Feshbach theory. The gamma-ray strength function for energies lower than 9 MeV has been extracted from the experiment.
Zeitschrift für Physik A Hadrons and Nuclei 02/1979; 293(1):43-51.
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12/1972;
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ABSTRACT: The gamma-ray decay of the 1658 keV resonance, which is a member of the isobaric analogues of the 1904 keV 3/2– level in44Ca, has been studied with a Ge(Li) detector. A number of gamma-ray transitions are described and associated with the decay of 15 levels between 1.50 and 3.05 MeV. These observations have made it possible to deduce spin and parity assignments to some of the levels. By comparing excited levels of43Sc and45Sc it has been possible to assign certain levels as members of one negative-parity band and two positive-parity bands withK
=1/2+ and 3/2+.
Zeitschrift für Physik A Hadrons and Nuclei 01/1972; 252(3):189-205.
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12/1971;
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ABSTRACT: Cross sections for the (n, p) reaction on 90,91,92,94Zr targets have been measured in the neutron energy range from 13 to 16.6 Me V and have been compared with predictions of the statistical and DWBA theories of multistep processes.
Nuclear Physics A. 510(1):93-105.
