The photonuclear reaction cross section of 58Co( γ , xp) reaction has been measured for the first time by employing the surrogate reaction technique. The cross section of the photonuclear reaction is obtained in the energy region 27–32 MeV. The compound nucleus 58 Co^* was populated using the transfer reaction 56Fe(6Li, α ) at E_lab= 35.9 MeV. To calculate the surrogate ratio, 61Ni( γ ,xp) was selected as the reference reaction and the corresponding compound nucleus 61 Ni^* was populated using the transfer reaction 59Co(6Li, α ) at E_lab= 40.5 MeV. Reference data taken from the recommended IAEA photonuclear database, which adopted the KAERI data in this case, have been used to determine the desired cross section. Compound nuclear cross section calculations have been done using the statistical nuclear reaction code TALYS 1.96.

18F radioactive isotope is widely used in PET imaging for nuclear medicine. Medical linear accelerators producing high-flux bremsstrahlung beams up to 20 MeV are commonly used in radiation therapy. Hence, the production of 18F through photon-induced channels will reduce many of the intricacies in transportation and handling. With this objective, the integral cross sections for 19F(γ, n)18F reaction, for bremsstrahlung endpoint energies of 12, 14.6, and 20 MeV, are measured employing the activation technique. The experimentally measured cross section was analysed using the nuclear reaction code TALYS 1.96. Parameters for level density models and gamma strength function models are optimized within the framework of a statistical approach.

Technetium-99 is a radioactive waste produced primarily in nuclear reactors. It is also left as radioactive waste in hospitals, directly from Tc-99m isomeric state. To bring down the quantity of technetium-99 radioactive waste, the nuclear reactions using photon beam is explored. The integral cross section of the reaction Tc-99(gamma, gamma ')Tc-99m has been determined using the photo-nuclear activation method. The experiment was done using bremsstrahlung photons having endpoint energies viz. 6, 9, 12, 16, and 20 MeV. In-115(gamma, gamma ')In-115m reaction has been used as a monitor reaction, for the flux normalization of the bremsstrahlung spectrum. Theoretical model calculations have been done using the nuclear reaction code Talys 1.9. Theoretical parameter values are optimized with the presently obtained data. Total cross sections are estimated and investigated the feasibility of re-utilization of the technetium-99 radioactive isotope.

The evaporation residue (ER) cross sections for the reaction F19+187Re→206Po⁎ are measured, in the excitation energy range of 86.1 to 118.4 MeV. The measured cross sections are compared with that of 30Si + 176Yb reaction populating the same compound nucleus. Theoretical calculations are performed using the coupled - channels calculations for the capture cross sections and statistical model calculations for the ER cross sections. The dependence of quasi fission on entrance channel parameters such as charge product (Z1Z2), mass asymmetry (α), target deformation (β2) and effective fissility (χeff) are studied.

Evaporation residue (ER) cross sections are measured for the reaction $^{30}\mathrm{Si}+^{176}\mathrm{Yb}$, which forms the compound nucleus $^{206}\mathrm{Po}^{*}$, over the excitation energy range from 47.68 to 113.73 MeV. Dependence of noncompound nuclear reaction on entrance channel parameters such as charge product (${Z}_{1}{Z}_{2}$), mass asymmetry ($\ensuremath{\alpha}$), deformation (${\ensuremath{\beta}}_{2}$) of the target, and isospin asymmetry ($\mathrm{\ensuremath{\Delta}}\frac{N}{Z}$) is explored. To analyze the experimental data the coupled-channels and the statistical model calculations are used. The measured ER cross sections are compared with the system,$^{12}\mathrm{C}+^{194}\mathrm{Pt}$ forming the same compound nucleus and also with $^{28}\mathrm{Si}+^{176}\mathrm{Yb}$, forming $^{204}\mathrm{Po}^{*}$ in the neighborhood. Observed suppression in the evaporation residue cross sections at higher energies may be attributed to the presence of the noncompound nuclear process.

The photo nuclear reaction cross section of $^{61}$Ni($\gamma$,xp) reaction have been measured by employing surrogate reaction technique. This indirect method is used for the first time to obtain the cross section of photo nuclear reaction. The compound nucleus $^{61}$Ni$^{*}$ was populated using the transfer reaction $^{59}$Co($^{6}$Li,$\alpha$) at E$_{lab}=$ 40.5 MeV. To calculate the surrogate ratio, $^{60}$Ni($\gamma$,xp) was selected as reference reaction and the corresponding compound nucleus $^{60}$Ni$^{*}$ was populated using the transfer reaction $^{56}$Fe($^{6}$Li,d) at E$_{lab}=$ 35.9 MeV. The experimental cross section data of the reference reaction has been taken from EXFOR data libraries. Compound nuclear cross section calculations have been done using EMPIRE 3.2.3 code.

Evaporation residue (ER) cross sections are measured for the reaction Si-30 + Yb-176, which forms the compound nucleus Po-206*, over the excitation energy range from 47.68 to 113.73 MeV. Dependence of noncompound nuclear reaction on entrance channel parameters such as charge product (Z(1)Z(2)), mass asymmetry (alpha), deforumation (beta(2)) of the target, and isospin asymmetry (Delta N/Z) is explored. To analyze the experimental data the coupled-channels and the statistical model calculations are used. The measured ER cross sections are compared with the system, C-12 + Pt-194 forming the same compound nucleus and also with Si-28 + Yb-176, forming Po-204* in the neighborhood. Observed suppression in the evaporation residue cross sections at higher energies may be attributed to the presence of the noncompound nuclear process.

Recoiled Compton electrons of 180 deg have been utilized to measure the energy distribution of high-intensity bremsstrahlung. An optimized detector-collimator configuration was used for detection and spectrum measurement of recoiled electrons. The spectrum has been reconstructed using Compton cross sections retrieved from the ENDF/B.VIII.0 library. The measured spectrum has been further validated using theoretical simulation by the Geant4 code with incorporating ENDF/B-VIII.0-recommended cross sections. The simulated spectrum matches the measured spectrum if the spatial spread and energy spread of the electron beam are accounted for in the simulations.

In this work we study the cosmological evolution of a two component model with non-relativistic dark matter and decaying vacuum of the form $\varLambda = \varLambda _{0} + 3 \beta H^{2}$ . We contrast the model with the supernovae data and found that the model parameter $\beta =-0.010$ when the interaction parameter, $b=0$ and is $\beta =-0.002$ when $b=0.001$ . The thermal evolution study of the model indicates that it obeys the generalized second of entropy and also satisfies the convexity condition, $\ddot{S} <0$ so that the model behaves like an ordinary macroscopic system which approaching a stable equilibrium thermal state at asymptotic conditions. The dynamical system analysis reveals that, the model posses a prior decelerated epoch represented by a saddle critical point and the late critical point represents an accelerating epoch which posses a convergence of phase-space trajectories from both the regions of the point hence can be considered as stable.