Effective moment of inertia for several fission reaction systems induced by nucleons, light particles and heavy ions

Compound nucleus effective moment of inertia has been calculated for several fission reaction systems induced by nucleons, light particles, and heavy ions. Determination of this quantity for these systems is based upon the comparison between the experimental data of the fission fragment angular distributions as well as the prediction of the standard saddle-point statistical model (SSPSM). For the systems, the two cases, namely with and without neutron emission corrections were considered. In these calculations, it is assumed that all the neutrons are emitted before reaching the saddle point.It should be noted that the above method for determining of the effective moment of inertia had not been reported until now and this method is used for the first time to determine compound nucleus effective moment of inertia. Hence, our calculations are of particular importance in obtaining this quantity, and have a significant rule in the field of fission physics. Afterwards, our theoretical results have been compared with the data obtained from the rotational liquid drop model as well as the Sierk model, and satisfactory agreements were found. Finally, we have considered the effective moment of inertia of compound nuclei for the systems that formed similar compound nuclei at similar excitation energies.Comment: 9 pages, 2 Figures, 2 Table

Synthesis of transactinide nuclei in cold fusion reactions using radioative beams

Chances of synthesis of transactinide nuclei in cold fusion reactions (one-neutron-out) reactions using radioactive beams are evaluated. Because intensities of radioactive beams are in most of the cases significantly lower than the ones of the stable beams, reactions with the highest radioactive beam intensities for the particular elements are considered. The results are compared with the recent ones obtained by Loveland who investigated the same nuclei.Comment: 5 page

Fission Decay Widths for Heavy-Ion Fusion-Fission Reactions

Cross-section and neutron-emission data from heavy-ion fusion-fission reactions are consistent with a Kramers-modified statistical model which takes into account the collective motion of the system about the ground state; the temperature dependence of the location of fission transition points; and the orientation degree of freedom. We see no evidence to suggest that the nuclear viscosity departs from the surface-plus-window dissipation model. The strong increase in the nuclear viscosity above a temperature of ~1 MeV deduced by others is an artifact generated by an inadequate fission model.Comment: 14 pg, 6 fig, submitted to Physical Revie

Scaling of the giant dipole resonance widths in hot rotating nuclei from the ground state values

The systematics of the giant dipole resonance (GDR) widths in hot and rotating nuclei are studied in terms of temperature T, angular momentum J and mass A. The different experimental data in the temperature range of 1 - 2 MeV have been compared with the thermal shape fluctuation model (TSFM) in the liquid drop formalism using a modified approach to estimate the average values of T, J and A in the decay of the compound nucleus. The values of the ground state GDR widths have been extracted from the TSFM parametrization in the liquid drop limit for the corrected T, J and A for a given system and compared with the corresponding available systematics of the experimentally measured ground state GDR widths for a range of nuclei from A = 45 to 194. Amazingly, the nature of the theoretically extracted ground state GDR widths matches remarkably well, though 1.5 times smaller, with the experimentally measured ground state GDR widths consistently over a wide range of nuclei.Comment: 15 pages, 4 figures, Accepted for publication in Physical Review

Activation cross-sections of proton induced reactions on nat^{nat}Sm up to 65 MeV

Activation cross sections for proton induced reactions on Sm are presented for the first time for $^{nat}$Sm(p,xn)$^{154,152m2,152m1,152g,150m,150g,149,148,147,146,145}$Eu, $^{nat}$Sm(p,x)$^{153,145}$Sm, $^{nat}$Sm(p,x)$^{151,150,149,148g,148m,146,144,143}$Pm and $^{nat}$Sm(p,x)$^{141}$Nd up to 65 MeV. The cross sections were measured via activation method by using a stacked-foil irradiation technique and high resolution gamma ray spectroscopy. The results were compared with results of the nuclear reaction codes ALICE, EMPIRE and TALYS (results taken from TENDL libraries). Integral yields of the activation products were calculated from the excitation functions.Comment: arXiv admin note: text overlap with arXiv:1411.716

Investigation of production routes for the 161Ho Auger-electron emitting radiolanthanide, a candidate for therapy

The radiolanthanide 161Ho (2.48 h) is a promising Auger-electron emitter for internal radiotherapy that can be produced with particle accelerators. The excitation functions of the natDy(p,xn)161Ho and natDy(d,x)161Ho reactions were measured up to 40 and 50 MeV respectively by using the stacked foil activation method and gamma-ray spectrometry. The experimental data were compared with results of the TALYS code available in the TENDL 2011 library [1]. The main parameters of different production routes are discussed

Activation cross-sections of long lived products of deuteron induced nuclear reactions on dysprosium up to 50 MeV

Activation cross-sections for production of 162m,161,155Ho,165,159,157,155Dy and 161,160,156,155Tb radionuclides in deuteron induced nuclear reactions on elemental dysprosium were measured up to 50 MeV for practical application and the test of the predictive power of nuclear reaction model codes. A stacked-foil irradiation technique and off-line gamma-ray spectrometry were used to determine the activities. No earlier cross-section data were found in the literature. The experimental data are compared with the predictions of the ALICE-D, EMPIRE-D and TALYS codes. Integral production yields were calculated from the fitted experimental data

Cross sections of deuteron induced reactions on nat^{nat}Sm for production of the therapeutic radionuclide 145^{145}Sm and 153^{153}Sm

At present, targeted radiotherapy (TR) is acknowledged to have great potential in oncology. A large list of interesting radionuclides is identified, including several radioisotopes of lanthanides, amongst them $^{145}$Sm and $^{153}$Sm. In this work the possibility of their production at a cyclotron was investigated using a deuteron beam and a samarium target. The excitation functions of the $^{nat}$Sm(d,x)$^{145153}$Sm reactions were determined for deuteron energies up to 50 MeV using the stacked-foil technique and high-resolution $\gamma$-ray spectrometry. The measured cross sections and the contributing reactions were analyzed by comparison with results of the ALICE, EMPIRE and TALYS nuclear reaction codes. A short overview and comparison of possible production routes is given

Fission-fragment mass distributions from strongly damped shape evolution

Random walks on five-dimensional potential-energy surfaces were recently found to yield fission-fragment mass distributions that are in remarkable agreement with experimental data. Within the framework of the Smoluchowski equation of motion, which is appropriate for highly dissipative evolutions, we discuss the physical justification for that treatment and investigate the sensitivity of the resulting mass yields to a variety of model ingredients, including in particular the dimensionality and discretization of the shape space and the structure of the dissipation tensor. The mass yields are found to be relatively robust, suggesting that the simple random walk presents a useful calculational tool. Quantitatively refined results can be obtained by including physically plausible forms of the dissipation, which amounts to simulating the Brownian shape motion in an anisotropic medium.Comment: 14 pages, 11 ps figure