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Representation of radiative strength functions within a practical model of cascade gamma decay
http://lt-jds.jinr.ru/record/71422
A practical model developed at the Joint Institute for Nuclear Research (JINR, Dubna) in order to describe the cascade gamma decay of neutron resonances makes it possible to determine simultaneously, from an approximation of the intensities of two-step cascades, parameters of nuclear level densities and partial widths with respect to the emission of nuclear-reaction products. The number of the phenomenological ideas used isminimized in themodel version considered in the present study. An analysis of new results confirms what was obtained earlier for the dependence of dynamics of the interaction of fermion and boson nuclear states on the nuclear shape. From the ratio of the level densities for excitations of the vibrational and quasiparticle types, it also follows that this interaction manifests itself in the region around the neutron binding energy and is probably different in nuclei that have different parities of nucleons.Vu, D.C.Tue, 02 May 2017 07:53:30 GMThttp://lt-jds.jinr.ru/record/714222017-04-26REPRESENTATION OF THE RADIATIVE STRENGTH FUNCTIONS IN THE PRACTICAL MODEL OF CASCADE GAMMA DECAY
http://lt-jds.jinr.ru/record/70784
D.C. VuMon, 12 Dec 2016 08:43:52 GMThttp://lt-jds.jinr.ru/record/70784Joint Inst. Nucl. Res.2016
LEVEL DENSITY, RADIATIVE STRENGTH FUNCTIONS FROM THE ($n_{th}, 2\gamma$) REACTION AND MAIN PROPERTIES OF THE ${}^{96}$Mo NUCLEUS
http://lt-jds.jinr.ru/record/60420
A. M. SukhovojWed, 27 Feb 2013 10:25:56 GMThttp://lt-jds.jinr.ru/record/60420Joint Inst. Nucl. Res.2008
PARTIAL LEVEL DENSITY OF THE n-QUASIPARTICLE EXCITATIONS IN THE NUCLEI OF THE $40 \le A \le 200$ REGION
http://lt-jds.jinr.ru/record/60409
A. M. SukhovojWed, 27 Feb 2013 10:25:13 GMThttp://lt-jds.jinr.ru/record/60409Joint Inst. Nucl. Res.2005
GENERAL TREND AND LOCAL VARIATIONS OF NEUTRON RESONANCE CASCADE GAMMA-DECAY RADIATIVE STRENGTH FUNCTIONS
http://lt-jds.jinr.ru/record/60279
A. M. SukhovojMon, 18 Feb 2013 19:53:01 GMThttp://lt-jds.jinr.ru/record/60279Joint Inst. Nucl. Res.2012
MODIFIED MODEL OF NEUTRON RESONANCE WIDTHS DISTRIBUTION. RESULTS OF TOTAL GAMMA-WIDTHS APPROXIMATION
http://lt-jds.jinr.ru/record/59281
A. M. SukhovojThu, 16 Aug 2012 08:21:31 GMThttp://lt-jds.jinr.ru/record/59281Joint Inst. Nucl. Res.2011
GAMMA-DECAY OF THE COMPOUND STATE AND CHANGE OF STRUCTURE OF THE <sup>124</sup>Te EXCITED LEVELS
http://lt-jds.jinr.ru/record/58789
A. M. SukhovojMon, 02 Jul 2012 12:28:59 GMThttp://lt-jds.jinr.ru/record/58789Joint Inst. Nucl. Res.2007On problems of experimental determination of reliable values of nucleus parameters at low excitation energy: $^{60}Ni$ as an example
http://lt-jds.jinr.ru/record/56161
The reanalysis of the published experimental data from reaction Co-59(p,2gamma)Ni-60 was performed. The region of the most probable values of level density and radiative strength functions of cascade gamma-transitions was determined. The obtained data were rather precisely approximated by the V.M. Strutinsky model and semi-phenomenological model - for strength functions. The region of appearance and magnitude of maximal errors of the calculated cross-section of nucleon emission in evaporation spectra in traditional methods of their analysis were determined as well. There was for the first time obtained methodically correct information on the radiation strength function of primary gamma-transitions in diapason of neutron binding energy with averaging over large set of initial levels.Sukhovoj, A.M.Tue, 02 Aug 2011 19:01:35 GMThttp://lt-jds.jinr.ru/record/56161Some practical limits on achievable precision of determination of nuclear-physics parameters
http://lt-jds.jinr.ru/record/56160
The status of experiments on determination of level density and partial widths of the nuclear reaction products emission in diapason of nucleon binding energy is presented. There are analyzed the sources and magnitude of probable systematical uncertainties of their determination. The maximally achievable precision of these parameters is estimated, as well. There is considered ability of new method for determination of distribution parameters of neutron resonances reduced widths in order to distinguish their groups with the same structure of wave functions. It was obtained in both cases that the insufficient value of maximally achievable precision of the parameters of the experimental data analysis does not allow one to obtain reliable and detailed information on the studied nuclear properties -- its entropy, strength functions of nuclear products emission and dominant level structure above 0.5Bn.Sukhovoj, A.M.Tue, 02 Aug 2011 19:01:35 GMThttp://lt-jds.jinr.ru/record/56160Parameters of Distribution of the Primary Gamma-Transition Intensities Following Resonance Neutron Capture and Some Properties of Compound Nuclei Gd-157,159
http://lt-jds.jinr.ru/record/30178
The re-analysis of the published experimental data on the primary gamma-transition intensities following neutron capture in different groups of neutron resonances in $^{156,158}$Gd has been performed. There are determined the most probable values of sum of E1 and M1 primary transitions, numbers of excited by them levels of both parities, ratios of radiative strength functions k(M1)/k(E1), dispersions of deviations of random values of intensities from the average and ratios of mean intensities of primary transitions to levels J=5/2 with respect to analogous data for J=1/2 and 3/2 (capture of the 24 keV neutrons) in narrow excitation energy intervals. All the data on level density and sums of radiative strength functions confirm the presence of clearly expressed step-like structure in level density below 3 MeV and general trend in change in strength functions as changing primary gamma-transition energy. Variations of distribution dispersions and, especially, ratio k(M1)/k(E1) (or $k(E1)/k(M1)$) at changing excitation energy point to strong change in structure of these nuclei above 1.0-1.5 MeV.Sukhovoj, A.M.Fri, 29 Oct 2010 09:42:13 GMThttp://lt-jds.jinr.ru/record/30178Level Density and Radiative Strength Functions of the U-237 Nucleus from the (anti-n,gamma) Reaction
http://lt-jds.jinr.ru/record/30177
The independent analysis of the published data on the intensities of the primary gamma-quanta following resonance neutron capture in $^{236}U$ has been performed. Distribution of these intensities about the mean value was approximated in different energy intervals of the primary gamma-transitions and neutrons. Extrapolation of the obtained functions to the zero registration threshold of the primary gamma-transition intensity allowed us to estimate (independently on the other experimental methods) expected level number of both parities for spin values J=1/2, 3/2 and sum of radiative widths for both electric and magnetic dipole gamma-transitions to levels with excitation energy up to $\approx 2.3$ MeV.Khitrov, V.A.Fri, 29 Oct 2010 09:42:13 GMThttp://lt-jds.jinr.ru/record/30177Parameters of Cascade Gamma-Decay of Compound-Nuclei Nd-146, Gd-156, Yb-172, Ta-182, W-184, Os-191, Th-231, Th-233, U-239, Pu-240 from Experimental Data of Reaction (anti-n,gamma)
http://lt-jds.jinr.ru/record/30176
Re-analysis of experimental data on primary gamma-transitions averaged over some energy intervals of neutron resonances has been performed. Approximation of their cumulative sums together with extrapolation of the obtained distribution to zero value allowed us to determine mean intensities of of E1- and M1-transitions, their probable number and total dispersion of intensity deviations from the mean value. The level density and sum of radiative strength functions determined in this way confirm main peculiarities of these nuclear parameters determined from intensities of the two-step gamma-cascades.Sukhovoj, A.M.Fri, 29 Oct 2010 09:42:13 GMThttp://lt-jds.jinr.ru/record/30176Possibility of Experimental Determination of Reliable Parameters of the Compound-State Gamma-Decay and Some Errors of Analysis: Mo-96 as an Example
http://lt-jds.jinr.ru/record/30174
Comparison between potential possibilities and inevitable systematic errors of one- and two-step reactions for obtaining of maximum reliable data on level density and radiative strength functions after decay of excited levels of complicated nuclei has been performed. It was shown that the use for this aim of two-step reactions instead of one-step reactions provides for potential possibility to decrease systematical errors of mentioned nuclear parameters, as minimum, by several times.Sukhovoj, A.M.Fri, 29 Oct 2010 09:42:13 GMThttp://lt-jds.jinr.ru/record/30174Calculation of the total gamma-spectra of the fast neutrons capture in the isotopes Sn-117, Sn-119 for the different parameters of cascade gamma-decay
http://lt-jds.jinr.ru/record/29509
The gamma-spectra were calculated for the set of different level densities and radiative strength functions. The sufficiently precise reproduction of the experiment is impossible without taking into account the influence of the process of the nucleons Cooper pairs breaking on any nuclei cascade gamma-decay parameters.Sukhovoj, A.M.Fri, 29 Oct 2010 08:40:38 GMThttp://lt-jds.jinr.ru/record/29509Problems of experimental determination of parameters of nucleus and applicability of the Bohr-Mottelson hypothesis
http://lt-jds.jinr.ru/record/29508
Population of a number of excited levels of 51V and 57Fe has been determined from the data of the ENDSF file up to the excitation energy of about 7 and 5.2 MeV, respectively. It cannot be reproduced in the region of their maximal energies in the framework of assumption on the independence of partial radiative widths on the structure of decaying level and excited one, at least, lower than 0.5Bn. Therefore, it is impossible to estimate the actual degree of reliability of data on the level density and radiative widths of cascade gamma-transitions in light spherical nuclei obtained from the spectrum analysis of nuclear reactions, which do not take into account this circumstance.Sukhovoj, A.M.Fri, 29 Oct 2010 08:40:38 GMThttp://lt-jds.jinr.ru/record/29508Approximation of Sums of Experimental Radiative Strength Functions of Dipole Gamma-Transitions in the Region E(gamma) ~= B(n) for the Atomic Masses 40 <= A <= 200
http://lt-jds.jinr.ru/record/29491
The sums k(E1)+k(M1) of radiative strength functions of dipole primary gamma-transitions were approximated with high precision in the energy region of $0.5 < E_1 < B_n-0.5$ MeV for nuclei: 40K, 60Co, 71,74Ge, 80Br, 114Cd, 118Sn, 124,125Te, 128I, 137,138,139Ba, 140La, 150Sm, 156,158Gd, 160Tb, 163,164,165Dy, 166Ho, 168Er, 170Tm, 174Yb, 176,177Lu, 181Hf, 182Ta, 183,184,185,187W, 188,190,191,193Os, 192Ir, 196Pt, 198Au, 200Hg by sum of two independent functions. It has been shown that this parameter of gamma-decay are determined by the structure of the decaying and excited levels, at least, up to the neutron binding energy.Sukhovoj, A.M.Fri, 29 Oct 2010 08:40:21 GMThttp://lt-jds.jinr.ru/record/29491Reanalysis of the process of the cascade gamma decay of Au-198 compound state
http://lt-jds.jinr.ru/record/29475
To further study the 'pygmy' resonance phenomena in the photon strength function, we reanalyzed the two-step cascade data for the target nucleus $^{197}$Au using the Dubna group approach. The range of obtained values allows for meaningful conclusions: the level density at low excitation energy shows a step-like behavior/ the electric dipole photon strength function has a broad maximum around $E_{\gamma}=5$ MeV and is not typical of a 'pygmy' resonance/ the level density below $B_{n}$ also demonstrates step-like behavior.Sukhovoj, A.M.Fri, 29 Oct 2010 08:40:16 GMThttp://lt-jds.jinr.ru/record/29475Nuclear structure of W-187 studied with (n, gamma) and (d, p) reactions
http://lt-jds.jinr.ru/record/29285
Bondarenko, V.Fri, 29 Oct 2010 08:39:00 GMThttp://lt-jds.jinr.ru/record/29285Possibilities to verify the level density and radiative strength functions, extracted from the two-step gamma-cascade intensities
http://lt-jds.jinr.ru/record/28801
The direct determination of the excitation level density and radiative strength functions of their exciting gamma-transitions is impossible for the larger part of the stable and long-life radioactive target nuclei. This circumstance is uniquely determined by the fact, that the level spacing much less than the resolution of the existing spectrometers of gamma-rays and charged particles. The extraction of these parameters of nucleus in this situation can be executed by their only fitting to the most probable values, reproducing the measured in the nuclear reactions spectra and sections. This inverse problem of mathematical analysis of its nature is principally ambiguous. Moreover, system of equations, those connecting the number of excitable levels and probability of the emission of charge particles are assigned usually within the framework of some assumptions about the mechanism of nuclear reaction and factors, determining the dynamics of the studied process. The verification of these parameters can be partially executed by the calculation of total gamma-spectra for their different sets. As, in particular, the results of this analysis show, the calculation of the structure of the excited levels to a change in the form of the energy dependence of radiative strength functions most likely must be considered to the neutron-binding energy. It is not possible to exclude the possibility of that, that also radiative, and neutron strength functions depend on the structure of neutron resonance and for the higher excitation energies.Sukhovoj, A.M.Fri, 29 Oct 2010 07:21:54 GMThttp://lt-jds.jinr.ru/record/28801On the correctness of various approaches in the extraction of the nucleus parameters on example of analysis of the two-step gamma-cascades in Dy-163 compound nucleus
http://lt-jds.jinr.ru/record/28800
The model-free analysis of experimental data in the intensities of two-step cascades into 163Dy shows, that the basically special features of the cascade gamma-decay of its compound-state completely correspond to those observed in other nuclei. Thus, the density of the levels in this nucleus with good precision it is reproduced as sum of three, five, seven-quasiparticle excitations with the tenfold, as the minimum, by an increase due to vibration type excitations. The greatest changes in the sum of the radiation strength functions of dipole primary gamma-transitions correlate with a change in the number of excitable quasi-particles. Accordingly, model presentations about the radiation strength functions of larger, than for those existing, accuracy must consider as a quantity of excited quasi-particles, so the presence of the vibration type excitations of all possible types. Moreover, the reliable picture of the studied process can be obtained only from the approximation of the distributions of the intensities of cascades in the function of energies of their primary gamma-transitions.Khitrov, V.A.Fri, 29 Oct 2010 07:21:54 GMThttp://lt-jds.jinr.ru/record/28800Level density and radiative strength functions of dipole gamma-transitions in Ba-139 and Dy-165
http://lt-jds.jinr.ru/record/27488
Level density and radiative strength functions which allow precise reproduction of the two-step cascade intensity, gamma width of compound state and cascade population of levels up to excitation energy of about 3.5 MeV were determined using experimental data on the (n,2gamma) reaction. Level density in these nuclei (like in other even-odd nuclei studied earlier) in wide excitation energy interval is considerably less than that predicted by Fermi-gas model. Enhancement of the radiative strength functions, caused by strong correlations between cascade gamma-decay parameters, most probably, relates with the change in ratio between the quasi-particle and collective components of the wave functions of the cascade intermediate levels in the region of most strong change in their density.Khitrov, V.A.Thu, 28 Oct 2010 18:39:21 GMThttp://lt-jds.jinr.ru/record/27488Level density and radiative strength functions of dipole gamma-transitions in Dy-163
http://lt-jds.jinr.ru/record/27482
Using our early experimental data on the cascade gamma-transitions from the 162Dy(n,2gamma) reaction, we determined dependence of the cascade intensity on the energy of their intermediate levels, and then - level density and radiatibe strength functions which allow precise reproduction of the experimental two-step cascade intensities and total gamma-width. Level density in this nucleus (like in other earlier studied even-odd nuclei) in the interval 1 to 3 MeV is considerably less than that predicted by Fermi-gas model. Enhancement of the radiative strength functions, caused by strong correlations of parameters, most probably, relates with the change in ratio between the quasi-particle and collective component of the wave functions of the cascade intermediate levels in the region of most strong change in their density.Khitrov, V.A.Thu, 28 Oct 2010 18:39:20 GMThttp://lt-jds.jinr.ru/record/27482Probable level densities and radiative strength functions of dipole gamma-transitions in Fe-57 compound nucleus
http://lt-jds.jinr.ru/record/27480
From the published results of experimental research of 56Fe(n,2gamma) reaction carried out in Budapest, the values of the most probable densities of cascade intermediate levels with 1/2, 3/2 spin and radiative strength functions of cascade E1 and M1 transitions in 57Fe compound nucleus have been determined. These results correspond to analogous data for other nuclei studied by us and contradict to predictions of conventional models.Sukhovoj, A.M.Thu, 28 Oct 2010 18:39:20 GMThttp://lt-jds.jinr.ru/record/27480Level density and radiative strength functions in light nuclei: Co-60 as an example of the method for determination and their reliability verification
http://lt-jds.jinr.ru/record/27478
Up to now, level density for some nuclei (close to construction materials of nuclear reactors with respect to their mass) was determined only from the evaporation nucleon spectra. All its energy dependences obtained are smooth enough functions and are usually reproduced in the frameworks of generalized model of the superfluid nucleus with the use of the phase transition energy of infinite and homogeneous macrosystem. The same data obtained from 59Co(n,2gamma) reaction demonstrate the presence of two clearly expressed step-like structures. This fact corresponds to the analogous data for other nuclei studied in the same way. Level density and radiative strength functions derived from two-step cascade intensities provide more precise reproduction of the total gamma-spectrum than conventional nuclear models.Sukhovoj, A.M.Thu, 28 Oct 2010 18:39:20 GMThttp://lt-jds.jinr.ru/record/27478Some problems in determining level density and radiative strength functions in light and near-magic nuclei
http://lt-jds.jinr.ru/record/27332
The values of some functional dependencies of level density and radiative strength functions that reproduce the experimental intensities of the two-step gamma-cascades to the ground and first excited states of 28Al have been determined. It was shown that the assumption about independence of the dipole cascade transitions radiative strength functions on energy of decaying level leads to rather essential error in observation of both level density and radiative strength functions.Sukhovoj, A.M.Thu, 28 Oct 2010 18:38:42 GMThttp://lt-jds.jinr.ru/record/27332