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Ammonium diuranate (ADU) is an important intermediate for the production of uranium base fuel. Controlling morphology of crystalline ADU powders is very important as it is retained by its subsequent products. Because of the high level of supersaturation, the involved mechanisms of precipitation like primary nucleation, crystal growth, aggregation and breakage occur simultaneously and they control the morphology. Effects of concentration of uranyl nitrate solution, temperature and the mixing intensity have been investigated on the morphology, crystal structure and the other physical properties of ADU. Effect of temperature is found to be more dominant for controlling morphology.

In the present study the quantitative phase analysis of Th-U alloys in bulk form namely Th-52 wt% U and Th-3wt%U has been performed over the data obtained from both X ray diffraction and neutron diffraction technique using Rietveld method of FULLPROF software. Quantifying thoria (ThO2) phase present in bulk of the sample is limited due to surface oxidation and low penetration of x rays in high Z material. Neutron diffraction study probing bulk of the samples has been presented in comparison with x-ray diffraction study.

Fusion and quasi-elastic scattering measurements have been carried out for $^{6,7}\mathrm{Li}$+$^{197}\mathrm{Au}$ systems in the energy range $E/{V}_{b}\ensuremath{\sim}0.7$ to 1.5. Coupled-channel calculations including coupling to inelastic states of the target and projectiles are able to explain an enhancement in measured fusion cross sections at energies below the barrier. At energies above the barrier the complete fusion cross sections are found to be suppressed compared to the coupled-channel predictions for both systems. A systematic comparison of fusion cross sections of the weakly bound stable nuclei $^{6,7}\mathrm{Li}$ and halo nuclei $^{6,8}\mathrm{He}$ on a $^{197}\mathrm{Au}$ target is presented. Barrier distributions from quasi-elastic scattering are seen to shift towards higher energies with respect to fusion after inclusion of the breakup-$\ensuremath{\alpha}$ channel for both $^{6}\mathrm{Li}$ and $^{7}\mathrm{Li}$.

Complete fusion cross sections have been measured using the off-line $\ensuremath{\gamma}$-ray spectroscopy method for the ${}^{6}$Li+${}^{90}$Zr system around barrier energies. Statistical and coupled-channel calculations have been performed to investigate the effect of coupling on complete fusion. It is observed that the complete fusion is suppressed by 34 $\ifmmode\pm\else\textpm\fi{}$ 8$%$ compared to the coupled channel predictions. The effect of breakup coupling is estimated using the continuum discretized coupled channels (CDCC) method and it is found to reduce the complete fusion probability. Contrary to earlier predictions, a universal behavior of complete fusion suppression factor for the ${}^{6}$Li projectile with target charge is observed.

The high-spin states in odd-odd $^{194}$Tl nucleus have been studied by populating them using the $^{185,187}$Re($^{13}$C, xn) reactions at 75 MeV of beam energy. $\gamma-\gamma$ coincidence measurement has been performed using the INGA array with a digital data acquisition system to record the time stamped data. Definite spin-parity assignment of the levels was made from the DCO ratio and the IPDCO ratio measurements. The level scheme of $^{194}$Tl has been extended up to 4.1 MeV in excitation energy including 19 new gamma ray transitions. The $\pi h_{9/2} \otimes \nu i_{13/2}$ band, in the neighboring odd-odd Tl isotopes show very similar properties in both experimental observables and calculated shapes. Two new band structures, with 6-quasiparticle configuration, have been observed for the first time in $^{194}$Tl. One of these bands has the characteristics of a magnetic rotational band. The cranked shell model calculations, using a deformed Woods-Saxon potential, have been performed to obtain the total Routhian surfaces in order to study the shapes of the bands and the band crossing in $^{194}$Tl. The semiclassical formalism has been used to describe the magnetic rotational band., Comment: Accepted for publication in Physical Review C

With the aim to investigate the in∞uence of the breakup channel on difierent reaction channels, the elastic scattering and fusion of 9 Be with the medium mass target 89 Y has been stud- ied at near barrier energies. Optical model analysis of the elastic data has been carried out and a dispersion relation applied to the real and imaginary potentials to investigate their energy depen- dence from which the presence of breakup threshold anomaly has been observed. Complete fusion (CF) cross sections, obtained for 9 Be+ 89 Y system, are found to be suppressed by (20 § 5)% as compared to the coupled-channels calculations without breakup coupling. This observation has been further conflrmed by comparing these cross sections with those for the 4 He+ 93 Nb and 12 C+ 89 Y systems, where fusion is induced by a tightly bound projectile and forms a nearby compound nu- cleus to that formed by 9 Be+ 89 Y. Results from the breakup coupling done in continuum discretized coupled-channels calculations show that the elastic cross sections thus obtained, which also flt the experimental elastic cross sections, are enhanced compared to the uncoupled calculations which im- plies a reduction in absorption/fusion cross sections. These enhanced cross sections suggest that the dynamic polarization potential produced due to breakup coupling is repulsive in nature. Thus the efiective (bare+polarization) potential around the barrier becomes less attractive leading to the absence of the normal threshold anomaly.

Excitation functions are measured for complete fusion and transfer reactions of 6 Li and 7 Li with 197 Au at energies around the Coulomb barrier. Coupled channel calculations including the couplings to both target and projectile excited states have been performed and are found to explain the data at energies below the barrier. At above barrier energies the complete fusion cross sections are found to be suppressed compared to the coupled channel calculations for both the systems. A systematic comparison of fusion cross-section for halo nuclei 6,8 He and weakly bound stable nuclei 6,7 Li on 197 Au target is also presented. Large neutron transfer cross-sections are observed for 6,7 Li as compared to tightly bound projectiles 12 C, 16 O.

The excitation function for the complete fusion of $^{9}\mathrm{Be}$$+$$^{89}\mathrm{Y}$ has been measured at near-barrier energies, and the barrier distribution has been extracted from the fusion data. Coupled-channels calculations have been carried out to understand the effect of coupling of both the projectile and target excitations on the above quantities. The complete fusion cross sections, especially at above-barrier energies, have been found to be suppressed by ($20\ifmmode\pm\else\textpm\fi{}5$)% compared to the ones predicted by the coupled-channels calculations that do not include the couplings to the projectile continuum, indicating the loss of flux from the entrance channel before fusion. This conclusion is also supported by a considerable incomplete fusion cross section observed for this system. Fusion measurements for two more systems have been carried out, namely, for $^{4}\mathrm{He}$$+$$^{93}\mathrm{Nb}$ and $^{12}\mathrm{C}$$+$$^{89}\mathrm{Y}$, which involve tightly bound projectiles and form compound nuclei nearby to that formed in $^{9}\mathrm{Be}$$+$$^{89}\mathrm{Y}$ fusion. Comparison of the fusion data obtained for all three systems further confirms the suppression of complete fusion in the $^{9}\mathrm{Be}$$+$$^{89}\mathrm{Y}$ system. Systematics of the suppression factor observed for $^{9}\mathrm{Be}$ induced fusion in different mass targets is discussed.