[en] Investigating the properties of exotic neutron-rich heavy nuclei is very important for nuclear astrophysical and nuclear structural studies. Especially the neutron rich nuclei around the neutron number N=126 plays a significant role in understanding the mechanism of heavy elements synthesis in r-process. Multi-nucleon transfer (MNT) in heavy nuclear reaction systems has been proposed as a one of the promising way for producing such nuclei. Several reactions such as ¹³⁶Xe + ¹⁹⁸Pt, ¹³⁶Xe + ²⁰⁸Pb, ²⁰³Hg +²⁰⁸Pb has been proposed to produce the neutron rich nuclei in this region. One also needs the reliable theory/models to quantitatively understand the outcomes of these reactions. In the present work the yields of over 200 projectile-like fragments (PLFs) and target-like fragments (TLFs) from the interaction of ¹³⁶Xe (Elab.=860 MeV) with a thick target of ¹⁹⁸Pt were measured using a gamma-ray spectroscopy (both off-line and on-line), giving a comprehensive picture of the production cross sections in this reaction. We have compared these results with the previous measurements and with the predictions of the semiclassical GRAZING, di-nuclear system (DNS) and Intermediate Quantum Molecular Dynamics (ImQMD) models. We find that that, neither the GRAZING nor DNS models correctly describes the measured TLF and PLF yields in this lower-energy reaction but the ImQMD model describes these yields adequately. The further details of the work will be presented. (author)

[en] In a recent work, direct measurement of neutron induced fission cross section of ²⁴¹Pu(T_1/2 = 14.1 yrs), has been carried out using neutron time of flight. Differences between the reported experimental measurement and evaluation by standard libraries exceeds by 30%, thus it is suggested to carry out further confirmatory measurements on ²⁴¹Pu(n,f) cross sections. In this paper, we report the use of ²³⁸U(⁶Li,d)²⁴²Pu and ²³²Th(⁶Li,d)²³⁶U transfer reactions as surrogate of ²⁴¹Pu(n,f) and ²³⁵U(n,f) compound nuclear reactions respectively. By employing the surrogate ratio method (SRM) and taking ²³⁵U(n,f) as reference, the ²⁴¹Pu(n,f) cross sections have been determined in the equivalent neutron energy range of 11.0 MeV-16.0 MeV

[en] In the present experiment performed at the BARC - TIFR Pelletron LINAC Facility, Mumbai, we looked for the resonances in the forward angles in the 110 MeV "2"4Mg ("1"2C, 2"1"2C) "1"2C reaction with "1"2C's detected in coincidence. Silicon ΔE - E detector telescopes (with ΔE being 15 micron to 30 micron) were used to detect 12 C's one at 20°, 30° in the upper arm and the others at -10°, -20° in the lower arm of the scattering chamber

[en] The knowledge of the neutron-induced reaction cross-section is important, especially, for the fusion and fission reactor technologies. In the absence of experimental data or for cases where measurements are difficult, theoretical predictions of nuclear cross-sections are needed to be improved upon using refined model calculations or effective semi-empirical formulas. Accurate, physics-based modelling of neutron-induced reactions is key to all nuclear science and technology applications. In the present work, the excitation functions for (n, p), (n, α) and (n, 2n) reactions up to 20 MeV for stable isotopes of Ti, Cr, Mn, Fe, Co, Ni, Cu, etc. are calculated using the EMPIRE- 3.2 nuclear reaction model code using optimised values of input parameters. The experimental data available in EXFOR database for these stable isotopes are reproduced to determine the optimum parameters. The optimised parameters, so obtained, are then used to calculate the reaction cross-sections for a series of unstable nuclides for the incident neutron energy of 1-20 MeV. The calculated cross-sections are compared with the evaluated data available in literature (ENDF). We have also compared our results with the estimated cross-sections using available empirical formulas. Based on the calculations, we recommend a reliable set of parameters to estimate the (n, p), (n, α) and (n, 2n) cross-sections for unstable nuclides in the mass region A ∼ 40–70. (author)

[en] The prompt fission neutron spectra for the fast neutron induced fission has been insufficiently studied experimentally. In the present work, results on first attempt to measure the prompt neutron emission spectra of ²³⁸U fission induced by 2.0 MeV neutron produced via ⁷Li(p,n)⁷Be reaction has been reported. The obtained spectra have been compared with the Maxwellian function and calculated data taken from Vladuca and Tudora et al. The Maxwellian temperature has also been deduced from present data and compared with the other experimental data reported earlier in the literature

[en] Developing Fusion technology is a dream project for cheap, abundant and green energy source for future generations. Efforts are underway to build a International Thermonuclear Experimental Reactor (ITER project) using D-T fusion reaction releasing 14-MeV neutrons. It is needed to perform detailed neutronics study to qualify materials for component design for the fusion reactors, as presently done for fission reactors. Generally stainless steel (SS) is used as a structural material having Fe, Ni, Cr, Mn, Co, Nb as main constituents (in SS316 content of Fe and 65%). Interaction of 14-MeV neutrons with structural material produces various long-lived radio nuclides. The assessment of the radiological hazard showed that the main contribution to activation comes from "5"4Mn, "5"6Mn, "5"5Fe, "5"7Co, "5"8Co, "6"0Co, "5"7Ni, "5"1Cr and "9"4Nb that originate from transmutation reactions of neutrons with the elements in the initial SS composition. Fusion neutronics studies have been done during many years considering only the stable isotopes of Cr, Fe, Ni. But in the development of D-T fusion reactor, large amount radio nuclides will be produced during reactor operation as well as after shutdown of the reactor. "5"5Fe is a primary dominant nuclide produced by neutron induced reaction on Fe, Co and Ni elements by "5"6Fe(n,2n), "5"4Fe(n, γ), "5"9Co(n, α) "5"6Mn(β"-) "5"6Fe(n,2n), and "5"8Ni(n, α) reactions. As of today, there is no experimental measurement of the "5"5Fe(n,p) cross-section

[en] In the previous works, alpha particle spectra up to energy 30 MeV were measured in a number of heavy ion reactions. In the present work, the detector systems were optimized to measure the alpha particle spectra well beyond this limit and also made improved statistical model comparisons employing variety of NLD prescriptions using the Empire3.1 and PACE4 codes. The reactions ¹¹B + ¹¹⁵In and ¹¹B + ¹⁹⁷Au were used in the present work to populate the desired residual nuclei of Z=52 and Z=82. Preliminary results from the present work are reported here

[en] Single crystals of Gd_3Ga_3Al_2O_1_2:Ce with B codopants were successfully grown using the Czochralski technique. The timing characteristics of the crystal was measured by coupling the crystal to photomultiplier tubes (PMT) or silicon photodiodes [Si(PIN)]. The two prompt γ-rays emitted in a cascade from "6"0Co or "2"2Na source were detected in coincidence using Gd_3Ga_3Al_2O_1_2:Ce,B crystal detectors and a BaF_2 detector. The time resolution of these crystals are observed to be better than that measured for CsI:Tl crystal coupled to PMT or Si(PIN) in an identical measurement setup. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

[en] The single crystal scintillators have been a key component in development of various radiation detectors having applications, including high-energy physics, medical imaging, geological explorations, nuclear industry and national security. Due to increasing applications, there is continuous demand and interest for new scintillation materials with improved performance. In recent years, Ce doped scintillator materials have attracted the attention of many researchers due to their excellent combination of light output and decay time. In this communication, we report results on our investigation of timing characteristics of GGAG (Ce) crystal

[en] Nowadays, there is an increasing interest in studying nucleon-induced fission of actinides at intermediate energies, i.e., between 20 and 200 MeV due to worldwide interest in accelerator-driven systems (ADS) for nuclear applications. Such systems consist of subcritical reactors driven by neutrons produced in a spallation sub-actinide target irradiated with energetic protons. This spallation process produces also energetic secondary protons which will still significantly contribute to the overall induced reactions. Neutron-and proton-induced reactions in this energy range are among the very important ones for the ADS design. The most probable process resulting from these reactions is fission, which will be accompanied by non-negligible pre- and post-scission neutron emission which will surely affect the subcriticality aspect of the proposed ADS reactor. Therefore, it is important to study neutron multiplicities and compare them with evaluations and predictions presently used for establishing the sub-criticality concept and criteria of a reactor design. Here we report our measurements on the prompt fission neutron spectra in "2"3"8U fission induced by proton at energies 14, 18 and 23 MeV