[en] An empirical expression has been obtained for double differential neutron yield distributions from proton induced reactions on thick stopping targets. Calculated neutron yield distributions using an exciton (hybrid) nuclear reaction model have been used to generate polynomial expressions relating neutron yield distributions (emission energy and angle) with incident proton energy and target mass. The present expression is obtained by fitting data for 39 elements from ⁹Be to ²⁰⁹Bi and for incident proton energies from 25 to 200 MeV

[en] Production cross sections of ¹⁴⁹Tb, ¹⁵⁰Tb and ¹⁵¹Tb radionuclides have been measured from ¹²C induced reactions on mononuclidic praseodymium target in the incident energy range 46-78 MeV. Measured cross section values were found lower than the theoretical values obtained from the statistical code PACE-II. The issue is important in understanding heavy ion induced reactions. (author)

[en] ${}^{97}$Ru is a key radionuclide sought for diagnostic imaging due to its low-energy and intense γ-rays of 215.7 keV and 324.5 keV. New reaction routes to produce this radionuclide are constantly being investigated. A crucial step in carrying out such reactions is a reliable beforehand estimate of the production cross section of radionuclide and optimization conditions through robust theoretical frameworks. Existing literature on α + ${}^{95}$Mo reaction has been freshly examined to understand the excitation function of ${}^{97}$Ru. The data have been compared to other reactions of different projectiles on medium-mass targets. The reaction codes pace4, empire-3.2.2, and talys-1.96 have been employed to decipher the reaction mechanism and check the predictive ability of underlying theoretical models. The yield of ${}^{97}$Ru at different projectile energies and thick target yield in the optimum energy range has also been determined from the theoretical modeling.

[en] Full text: The Saha Institute of Nuclear Physics, Kolkata, has initiated a state-of-the-art Trace Analysis laboratory in the XIth five year plan project. The trace analysis laboratory is equipped with both nuclear and nonnuclear detection systems. The most noteworthy ultra-trace detection system is ICP-MS (XSeries-II), procured from Thermo Fisher Scientific. The ICP-MS is one of the most versatile machines amongst the available models. The machine has collision cell technology to suppress the isobaric interference. The machine has option to use NH₃ as collision gas in addition to H₂, He, H₂-He mixture, O₂, N₂ gases. Presently the machine has been calibrated by aqueous multi-elemental standard. However in near future it will be coupled with HPLC and GC, so that information on the speciation can be obtained in ultra-trace level. It has also been planned to couple the machine with Laser Ablation (LA) system, so that LA-ICPMS can directly determine trace elements in solid matrix. The trace analysis laboratory of SINP also equipped with ICP-OES, high purity Ge detector and a powerful compton suppression system. Therefore, the results can be validated in more than one competing method

[en] Heavy-ion reactions have become obligatory for probing the prevalent reaction dynamics or nuclear structure. The emission of light particles during the redistribution of energy amongst the degrees of freedom of composite system prior to attaining equilibrium is termed preequilibrium (PEQ) emission. Larger yield in the high energy tail of excitation functions of n emitting channels relative to equilibrium (EQ) based calculations are realized as signatures of PEQ. PEQ emissions were anticipated to occur at high excitation energies. However, recent advancements suggest PEQ signatures even at relatively low incident energies (below 7 MeV/A) where EQ is expected to be dominant. Observation of PEQ at low energies has renewed interest in concretizing the PEQ contribution in the heavy-ion induced reactions as both processes compete at such low energies. In this regard we aim to study ⁶Li+⁹³Nb reaction as we have observed the PEQ signatures in ⁷Li+⁹³Nb reaction. Fusion-evaporation cross sections were measured for ⁶Li+⁹³Nb reaction within 24-43 MeV range. We have discussed the role of mechanisms feeding the production of ⁹⁷Ru residue (populated via 2n channel) by comparing the measured excitation function with PACE and EMPIRE estimates

[en] A complete grasp of the weakly bound heavy-ion fusion reaction in the stable target nuclei is important to comprehend the extent of the various processes such as complete fusion (CF), incomplete fusion (ICF), nucleon transfer reactions, quasi-fission, equilibrium (EQ) and pre-equilibrium (PEQ) emissions, etc. reported so far. A systematic study of the PEQ reaction processes is especially worthy as they cater to facts about the dynamics of the excited composite system and the process to attain statistical equilibrium. A substantial contribution from the PEQ reaction process has been observed in the high energy tail of the excitation function of the residues produced in the light heavy-ion reactions. Besides EQ and PEQ proce sses, ICF starts competing in case of the weakly bound projectile, even at the very low energies. Therefore, understanding the reaction dynamics in the low to medium energy range, generation of experimental nuclear reaction data, and finding the appropriate theoretical explanation of them are essential. Recently, some weakly bound ⁷Li and ¹²C induced reactions on the stable targets having mass number ∼ 90 up to 7 MeV/ nucleon energy by measuring the residual cross-sections, have been studied. The PEQ emission of neutrons and protons is evident in all the reactions, particularly at the high energies. An indication of the occurrence of ICF has been observed in all the ⁷Li-induced reactions along with the predominant CF process, while only the CF mechanism was confirmed for the ¹²C-induced reactions. The strengths of the PEQ and ICF processes were quantified. Based on the experimental study, physical production parameters were also suggested for the optimum production of neutron deficient radionuclides such as ⁹⁷Ru, ^93mMo, etc. which have the potential to be used in the field of nuclear medicine. The talk will address those interesting observations

[en] Earlier we reported theoretical studies on the probable production of astatine radionuclides from ^6,7Li- and ⁹Be-induced reactions on natural lead and thallium targets, respectively. The production of astatine radionuclides were investigated experimentally with two heavy-ion-induced reactions: ⁹Be + ^natTl and ⁷Li + ^natPb. Formation cross sections of the evaporation residues, ^{207,208,209,210}At, produced in the (HI,xn) channel, were measured by the stacked-foil technique followed by off-line γ spectrometry at low incident energies (<50 MeV). Measured excitation functions were interpreted in terms of a compound nuclear reaction mechanism using Weisskopf-Ewing and Hauser-Feshbach models. Measured cross-section values are lower than the respective theoretical predictions.

[en] Production cross sections of evaporation residues, ¹⁴⁹Tb, ¹⁵⁰Tb, ¹⁵¹Tb, and ¹⁴⁹Gd, are measured using the stacked foil technique followed by off-line γ-spectrometry in ¹²C-induced reactions on naturally abundant mononuclidic praseodymium target in the 44- to 79-MeV incident energy range. Measured data are interpreted by comparison with previous measurements and theoretical predictions of the nuclear reaction model code PACE4. About 5% and 14% of the theoretical cross sections have been measured for ¹⁴⁹Tb and ¹⁵⁰Tb, respectively. The new cross sections of ¹⁴⁹Tb complement those measured earlier by α spectrometry. Cross sections of ¹⁵¹Tb are comparable to the theory. Cumulative cross sections of ¹⁴⁹Gd shed light on the nuclear reaction mechanism. In addition, the discussion shows the feasibility of producing ¹⁴⁹Tb in p- and α-induced reactions on gadolinium isotopes.

[en] Study of heavy-ion induced reactions on intermediate or heavy mass targets is necessary to understand the pre-equilibrium (PEQ) emissions, complete and incomplete fusion reactions, nucleon transfer processes etc. In heavy-ion induced reactions, PEQ emission of neutrons are observed at relatively low projectile energy (4-10 MeV/A). PEQ emissions in "1"2C- and "1"6 O-induced reactions on intermediate/ heavy mass targets like "1"2"8Te, "1"5"9Tb, "1"9"7Au, "6"4Ni etc. in 4-10 MeV/A energy range were reported. However heavy-ion induced reaction data near the barrier is still rare in order to develop sophisticated formalism for PEQ reactions in 4-10 MeV/A, low energy range. For the first time, production of "1"0"1","1"0"0","9"9Pd radionuclides via neutron channels is reported in "1"1B induced reaction on natural niobium ("9"3Nb) target in 3-5 MeV/A. Although "1"0"1"m","1"0"0","9"9Rh, "9"7Ru radionuclides have also been identified, but this report is focused on the production of Pd-isotopes.

[en] This study indicates that the "1"1B induced reaction on natural Y is also an efficient route for the production of nca neutron deficient "9"7Ru. Although cross-sectional data are obtained just at two energies and not sufficient to derive significant conclusion on the reaction mechanism, but the measured cross-sectional data are in agreement with Houser-Feshbach model estimation. The data also shed light on the compound nuclear reaction as a major contributor. We look forward to study the reaction in the energy range ∼30-70 MeV in near future