[en] Currently, antimony-125 is produced by recovery from tin-124 irradiated by neutrons in nuclear reactors. The radionuclide builds up following the pathway: Sn-124 (n,γ) → Sn-125 (β^-) (9.6 days) → Sb-125 ((β^-) (2.77 years) The cross-section of the (n,γ) reaction is low (0.2 barn), therefore tin metal enriched with tin-124 is used. It should be noted that the use of an enriched target decreases the build-up of other radionuclides as compared to the natural mixture of tin isotopes. Published data showed that ion exchange on anion exchangers is one of the most promising procedures of recovery of antimony-125 from irradiated tin-124. We irradiated tin metal enriched with tin-124 (approximately 96%). After cooling and storage, the specific activity was 5 μCi per g of metal. The irradiated sample was dissolved in concentrated hydrochloric acid containing hydrogen peroxide or bromine in order to convert tin to the tetravalent state and antimony to the pentavalent state. We used tin-119m as a mark for an express gamma-spectrometric determination of the distribution coefficients. We studied the separation of Sb-125 and tin on strongly basic (Dowex-50 and AV-17), moderately basic (AN-2FN), and weakly basic (AN-31) ion exchangers. Hydrochloric acid, a mixture of hydrochloric and hydrobromic acids, and nitric acid were used as the elutriating agents. The samples from chromatography were subjected to gamma-spectrometric analysis using Si(Li) and Ge(Li) semiconductor detectors. In experiments examining the separation on strongly basic anion exchangers, the attained decontamination factor for removal of tin from antimony-125 was approximately 10⁴-10⁵ in one cycle. In the experiments devoted to the separation on moderately basic and weakly basic anion exchangers, tin was eluted before antimony-125. This should improve reasonably the regeneration of the enriched tin samples. The most interesting and significant results were obtained in the study of separation of antimony-125 and tin on the AN-31 weakly basic anion exchanger. Tin was eluted virtually completely from the column with 8-9 free volumes of 0.8M HCl. Antimony-125 remained on the column and could be eluted efficiently with 7-8 free volumes of aqueous nitric acid (1:10 v/v). The tin and antimony-125 yields were 99% and 98%, respectively, and the antimony-125 content of tin did not exceed 0.1% of the initial activity. This procedure was patented in Russia (RF Patent No. 2,003,094, 12 July 1991). (author)

[en] Separation of ¹²⁵Sb from tin using highly basic, medium-basic, and weakly basic ion-exchangers was studied. The best results were obtained for AN-31 weakly basic anion exchanger. The yield of ¹²⁵Sb was 95 -98 % of the initial activity, the yield of tin, 98 ± 0.5% of the initial amount. The separation coefficient is 10⁶-10⁷ for one cycle. A procedure based on ion exchange was developed. Extraction procedures of separation of ¹²⁵Sb from tin were studied. Isoamyl alcohol, ethyl acetate, and di-n-butyl ether were used as extracting agents. The most efficient extracting agent is di-n-butyl ether. Carrier-free radiochemically pure sample of ¹²⁵Sb was produced. More than 20 mCi of the target product was recovered. The extraction recovery procedure of ¹²⁵Sb has been developed. (author)

[en] Within a microscopic transport model (Stochastic Mean Field) we analyze the collective flow properties associated to the intermediate mass fragments produced in nuclear fragmentation. We study the transverse and elliptic flow parameters for each rank in mass hierarchy. The results are plotted for ¹²⁴Sn + ¹²⁴Sn systems at an energy of 50AMeV and for an impact parameter b=4fm. The correlation with the dynamics of the isospin degree of freedom is also discussed and the results are presented for the same systems

[en] The symmetric system ¹¹²Sn+¹¹²Sn on the neutron poor side will be compared with the neutron rich system ¹²⁴Sn+¹²⁴Sn. The measurement of an incident energy of E/A=40 MeV was carried out with a nearly 4 π-coveraged for both, charged particles and neutrons. By varying the mass of this symmetric system without changing the charge we are able to address the isopin dependence of nuclear fragmentation. the correlation of the number emitted charged particles and the number of emitted neutrons will be presented. Impact parameter scales derived from different observables will be discussed. The comparison of the two systems in terms of fragment-production will be investigated

[en] Using symmetric Sn¹¹²+Sn¹¹², Sn¹²⁴+Sn¹²⁴ collisions as references, we probe isospin diffusion in peripheral asymmetric Sn¹¹²+Sn¹²⁴, Sn¹²⁴+Sn¹¹² systems at an incident energy of E/A=50 MeV. Isoscaling analyses imply that the quasiprojectile and quasitarget in these collisions do not achieve isospin equilibrium, permitting an assessment of isospin transport rates. We find that comparisons between isospin sensitive experimental and theoretical observables, using suitably chosen scaled ratios, permit investigation of the density dependence of the asymmetry term of the nuclear equation of state

[en] We show that the new experimental data reported by Galaviz et al. [Phys. Rev. C 71, 065802 (2005)] can be used to improve a previous optical potential global parameter set, employing the corresponding former local parameter basis as well as the parameter sets obtained through a similar analysis of the new data

[en] Mean lifetimes of five levels in the S band and three levels in the ground-state band of ¹⁵⁶Dy, populated via the ¹²⁴Sn(³⁶S,4n) reaction at E=145 MeV, were measured by the Doppler-shift attenuation technique using a line-shape analysis. The differential decay-curve method was applied for a lifetime determination. In contrast with earlier data, the present B(E2) values in the yrast band do not indicate a reduction in the collectivity after the crossing between the S band and the ground-state band, and confirm the results of theoretical calculations using mean-field approaches

No abstract available

[en] The study of nuclear stopping in the past few years makes it a topic of considerable interest. Nuclear stopping governs most of the dissipated energy during the collision of heavy ions. Thus it can provide important information about the nuclear equation of state under the extreme conditions of temperature, pressure and density. In the present study, nuclear stopping due to fragments is studied by analysing the phase space of fragments at different incident energies. The simulations are carried out by using the isospin-dependent quantum molecular dynamics (IQMD) model explained in the next section

[en] The elastic scattering of ³⁵Cl on ²⁷Al, ⁵⁸⁶²Ni, ^116120124Sn and ¹⁴¹Pr has been measured at energies between 100 and 170 MeV. Interaction radii are extracted with the quarter point method. Comparisons with trend formulas for the interaction radii are presented. The consistency of these radii with fusion radii is discussed. Optical model analyses are being performed for these systems as well as analyses by the Fresnel scattering model of Brink and Rowley