In the 4.93, 6.61, 8.31 and 10.92 MeV spectrum averaged neutron-induced fission of 232 Th, independent isomeric yield ratios (IR) of the fission products 131m,g Te and 133m,g Te have been experimentally determine. An off-line gamma-ray spectrometric technique was used for the measurement. The average neutron energies used were obtained from the 7 Li(p, n) reaction by using the proton energies of 7, 11, 15 and 18.8 MeV. From the IR values, the root mean square fragment angular momenta ( J RMS ) were deduced by applying spin dependent statistical model analysis. The effect of nuclear structure and role of excitation energy on the IR and J RMS values of 131m,g Te and 133m,g Te were examined.

In the 4.93, 6.61, 8.31 and 10.92 MeV spectrum averaged neutron-induced fission of Th-232, independent isomeric yield ratios (IR) of the fission products Te-131m,Te-g and Te-133m,Te-g have been experimentally determine. An off-line gamma-ray spectrometric technique was used for the measurement. The average neutron energies used were obtained from the Li-7(p, n) reaction by using the proton energies of 7, 11, 15 and 18.8 MeV. From the IR values, the root mean square fragment angular momenta (J (RMS)) were deduced by applying spin dependent statistical model analysis. The effect of nuclear structure and role of excitation energy on the IR and J (RMS) values of Te-131m,Te-g and Te-133m,Te-g were examined.

The cross sections of the 116Cd(n,2n)115m,gCd, natCd(n,xn)109,107Cd, and natCd(n,pxn)113,112,111g,,110mAg reactions were measured at average neutron energies ranging from 20.1 to 32.7 MeV using the activation method combined with off-line γ-ray spectrometry. Fast neutrons were produced via the 9Be(p, n) reaction using 35 and 45 MeV proton beams delivered by the MC-50 Cyclotron at the Korea Institute of Radiological and Medical Sciences (KIRAMS). The neutron energy spectra were simulated using the MCNPX 2.6.0 code, while the neutron flux was experimentally determined using the 27Al(n, α)24Na monitor reaction. The present results, together with literature data at lower energies, were compared with theoretical calculations from TENDL-2021 library and evaluated data from the JEFF-4.0 library. Overall, good agreement was observed in most of the cases.

The flux-weighted average cross-sections of the Pd-nat(n,xn)Pd-109,Pd-101 and Pd-nat(n,pxn)Rh-105,Rh-106m reactions with the average neutron energies of 20.3-32.3 MeV were measured for the first time by using an activation and off-line gamma-ray spectrometric technique. The fast neutrons were generated by using the Be-9(p,n) reaction with the proton energies of 35- and 45-MeV from the MC-50 Cyclotron at the Korea Institute of Radiological and Medical Sciences (KIRAMS). The neutron spectra were simulated by using the computer code MCNPX 2.6.0, whereas the experimental neutron fluxes were measured by using the Al-27(n,alpha)Na-24 monitor reaction. Thus the experimentally obtained reaction cross-sections are for the spectrum neutron energies, which range from the threshold energy to 33.0 MeV and 42.8 MeV, respectively. The present data within the average neutron energy of 20.3-32.3 MeV and the literature data at lower energy were compared with the theoretically calculated values from the TENDL-2019 library and found to be in good agreement in most of the cases.

The flux-weighted average cross-sections of the nat Pd(n,xn) 109,101 Pd and nat Pd(n,pxn) 105,106m Rh reactions with the average neutron energies of 20.3–32.3 MeV were measured for the first time by using an activation and off-line γ -ray spectrometric technique. The fast neutrons were generated by using the 9 Be(p,n) reaction with the proton energies of 35- and 45-MeV from the MC-50 Cyclotron at the Korea Institute of Radiological and Medical Sciences (KIRAMS). The neutron spectra were simulated by using the computer code MCNPX 2.6.0, whereas the experimental neutron fluxes were measured by using the 27 Al(n,α) 24 Na monitor reaction. Thus the experimentally obtained reaction cross-sections are for the spectrum neutron energies, which range from the threshold energy to 33.0 MeV and 42.8 MeV, respectively. The present data within the average neutron energy of 20.3–32.3 MeV and the literature data at lower energy were compared with the theoretically calculated values from the TENDL-2019 library and found to be in good agreement in most of the cases.

The cumulative yield of the fission products within the mass range of 83-117 and 123-153 have been measured in the 6.61and 10.92 MeV quasi-mono-energetic neutron-induced fission of U-238 by using an off-line gamma-ray spectrometric technique. The neutron beams were obtained from the 7 Li(p,n) reactions with the proton energies of 11 and 18.8 MeV. The mass chain yields were obtained from the cumulative yields by using charge distribution correction. The peak-to-valley (P/V) ratio, the average value of light mass (< AL >), heavy mass (< AH >) and the average number of neutrons () were obtained from the mass yield data. The data in the U-238(n, f) reaction from the present work and literature at various energies were compared with the similar data in the U-238( gamma , f) reaction and following observations were obtained. (i) In both the reactions, the mass yield distributions are double humped. (ii) The yield of fission products for A = 133-134, A = 138-139, and A = 143-144 and their complementary products are higher than those of other fission products due to the nuclear structure effect. (iii) The yield of symmetric product increases and thus the peak-to-valley (P/V) ratio decreases with excitation energy. (iv) With the increase of excitation energy, the vale increases in a similar way in both the reactions. (v) The changing trend of < AL > and < AH > values with the increase of excitation energy are entirely different in between the two reactions.

The flux -weighted average cross sections ofnatAg(gamma,xn)103-106Ag reactions were measured with the bremsstrahlung end -point energy of 70 and 75 MeV using an activation and off-line gamma-ray spectrometric technique. The GEANT4 code was used for the simulation of the bremsstrahlung spectra. The cross sections of natAg(gamma,xn) 103106Ag reactions as a function of mono -energetic photons were theoretically calculated by using the TALYS-1.96 code. The data of the present work and literature at different bremsstrahlung end -point energy are found to be in agreement with the theoretical values within the uncertainty limit. It can be seen that the flux -weighted average cross sections of the natAg(gamma,xn)105.106Ag reactions increase with bremsstrahlung energy up to the Giant Dipole Resonance region. Thereafter, a small decrease trend with the bremsstrahlung energy was seen due to the opening of another reaction channel.

For the first time, charge distribution studies have been carried out in the epi-cadmium neutron-induced fission of Pu-241 by measuring the fractional cumulative yields (FCYs) and independent yields of various fission products by using an off-line gamma-ray spectrometric technique. The average energy of the epi-cadmium neutron spectrum is 1.9 MeV. From the FCY values, the isobaric width parameter sigma(Z), most probable charge Z(P), and charge polarization triangle Zeta(EXPT) as a function of fragment mass were obtained. On the other hand, from the independent yield values, isotopic width parameter sigma(A); the most probable mass A(P); and the elemental yields Y-Z of Sn, Sb, Te, I, Xe, Cs, Ba, La, Ce, and Pr were determined by using a nonlinear fit. From the Y-Z values, the proton even-odd effect delta(p) was obtained for the first time. The present data were compared with similar data in the Pu-241(n(th),f) reaction and epi-cadmium neutron-induced fission of Pu-240 as well as other actinides to examine the role of the excitation energy and pairing effect.

In the epi-cadmium neutron-induced fission of Pu-239, cumulative and independent yields of various fission products within the mass ranges of 83 to 117 and 123 to 156 have been measured by using an off-line gamma-ray spectrometric technique. The spectrum average neutron energy is 1.9 MeV. Charge distribution correction on the cumulative yields was applied to obtain their post-neutron mass yields. Mass yield distribution parameters such as the peak-to-valley (P/V) ratio, the full-width at tenth-maximum of light and heavy mass wings, the average light mass and heavy mass , and the average neutron number were obtained. The mass yields in the epi-cadmium and thermal neutron-induced fission of Pu-239 were compared to examine the role of excitation energy on the P/V ratio and the nuclear structure effect.

Charge distributions have been carried out in the epi-cadmium neutron induced fission of 233U for the first time by measuring the fractional cumulative yields (FCY) and independent yields (IY) of various fission products. The method of an off-line γ-ray spectrometric technique was used for the measurement. From the FCY values, the isobaric width parameter (σZ), most probable charge (ZP) and the charge polarization (ΔΖEXPT) as a function of fragment mass were obtained. Similarly, from the IY values, isotopic width parameter (σA), the most probable mass (AP) and the elemental yields (YZ) of Sn, Sb, Te, I, Xe, Cs, Ba, La, Ce and Pr were determined by using a non-linear fit. From the YZ values, the proton even-odd effect (δp) was obtained for the first time. The present data were compared with the similar data in the thermal neutron induced fission of 233U and other actinides to examine the role of excitation energy on charge distribution parameters.

In the epi-cadmium neutron induced fission of 235U, independent isomeric yield ratios (IR) of fission products 130,132Sb, 131,133Te, 134,136I, 135Xe and 138Cs have been measured by using an off-line gamma-ray spectrometric technique. The average neutron energy of the epi-cadmium reactor neutron spectrum is 1.9 MeV. From the IR values, the root mean square fragment angular momenta (JRMS) were deduced by using spin dependent statistical model analysis. The IR and JRMS values of considered fission products in the epi-cadmium neutron induced fission of 235U were compared with the literature data in the thermal neutron induced fission of 235U to examine the influence of excitation energy on nuclear structure effect.

Studies on charge distribution have been carried out in the epi-cadmium neutron induced fission of 238Pu for the first time. Experimentally fractional cumulative yields (FCY) and independent yields (IY) of various fission products have been measured by using an off-line γ-ray spectrometric technique. From the FCY values, the charge distribution parameters such as the isobaric width parameter (σZ), most probable charge (ZP) and the charge polarization (ΔΖEXPT) as a function of fragment mass were obtained. On the other hand, from the measured IY values, isotopic width parameter (σA), the most probable mass (AP) and the elemental yields (YZ) of Sn, Sb, Te, I, Xe, Cs, Ba, La, Ce and Pr were determined by using a non-linear fit. From the YZ values, the proton even-odd effect (δp) was obtained for the first time. The isobaric and isotopic charge distribution parameters in the 238Pu(nf, f) reaction were compared with the similar data in the thermal neutron induced fission of 238Pu and other actinides to examine the role of excitation energy.

Measurement of independent isomeric yield ratios (IR) of 128,130,132Sb, 131,133Te, 132.134,136I, 135Xe and 138Cs have been carried out for the first time in the epi-cadmium neutron induced fission of 239Pu by using an off-line gamma-ray spectrometric technique. The average neutron energy () of the epi-cadmium reactor neutron spectrum is 1.9 MeV. From the IR values, root mean square fragment angular momenta (JRMS) were deduced by using spin dependent statistical model analysis. Effect of nuclear structure on JRMS values was examined. The present data in the epi-cadmium neutron induced fission of 239Pu were compared with the similar data in the thermal neutron induced fission of 239Pu to examine the role of excitation energy on JRMS values.

The 112Cd(n,2n)111mCd and 112Cd(n,p)112Ag reaction cross sections have been measured at the neutron energy of 14.54 ± 0.24 MeV by using the method of activation and off-line γ -ray spectroscopy. The mano-energetic neutrons were obtained from the D–T reaction using the Purnima Neutron Generator at BARC. The 197Au(n,2n)196Au and115In(n, n1)115mIn reactions were used for neutron flux monitors. The covariance analysis for the uncertainties in the measured reaction cross sections has been done based on various uncertained attributes. The experimental values were compared with the theoritically calculated values from TALYS-1.95 code, evaluated data from different libraries and literature data based on EXFOR compilation.

For the first time, charge distribution studies have been carried out in the epi-cadmium neutron induced fission of 235U by measuring the fractional cumulative yields (FCY) and independent yields (IY) of various fission products. An off-line γ-ray spectrometric technique was used for the measurements. The average energy of the epi-cadmium neutron spectrum is 1.9 MeV. From the FCY values, the isobaric width parameter (σZ), most probable charge (ZP) and the charge polarization (ΔΖEXPT) as a function of fragment mass were obtained. Similarly, from the IY values, isotopic width parameter (σA), the most probable mass (AP) and the elemental yields (YZ) of Sn, Sb, Te, I, Xe, Cs, Ba, La, Ce and Pr were determined by using a non-linear fit. From the YZ values, the proton even-odd effect (δp) was obtained for the first time. The present data in the 235U(n, f) reaction were compared with the similar data in the 235U(nth, f) and 238U(n, f) reactions as well as of other actinides to examine the role of excitation energy and pairing effect.

The 107 Ag(n, 2n) 106m Ag reaction cross sections at the neutron energies of 10.50 ± 0.68, 13.52 ± 0.67, 16.86 ± 0.58 and 19.86 ± 0.59 MeV were measured by using the off-line γ-ray spectroscopy and activation analysis techniques. The 7 Li( p , n ) reaction was used to produce the high-energy quasi-monoenergetic neutrons with the proton beam from the 14UD BARC-TIFR Pelletron facilities at Mumbai, India. The neutron flux was monitored using the standard 27 Al( n , α ) 24 Na monitor reaction. The detailed uncertainties analysis in the measured cross sections was performed using the covariance analysis. The cross sections were also theoretically calculated using TALYS-1.9 code from 10 to 25 MeV energies. The measured cross-sections data are compared with the evaluated data from TENDL-2019, JENDL-4.0 and ENDF/B-VIII.0 libraries as well as with the existing experimental data available in EXFOR compilation. Our data show good agreement with some of the previous experimental data and with the theoretical values calculated with TALYS-1.9 code. Present work will provide better description of level density models and pre-equilibrium process.

Post-neutron mass yield distribution in the epi-cadmium neutron-induced fission of U-233 has been carried out by measuring the cumulative yields of various fission products within the mass ranges of 77 to 117 and 123 to 153 using an off-line gamma-ray spectrometric technique. Independent yields of a few fission products were also measured by using the same technique. Charge distribution correction has been applied on cumulative yields to obtain the post-neutron mass yields. The mass yield distribution parameters such as full-width at tenth-maximum of light and heavy mass wings, the average light mass L> and heavy mass H>, and the average number of neutrons were obtained. The spectrum average neutron energy is 1.9 MeV. Thus, the role of excitation energy on the nuclear structure effect was examined by comparing the mass yield data in between the epi-cadmium and thermal neutron-induced fission of U-233.

The independent isomeric yield ratios (IR) of 128,130,132Sb, 131,133Te, 132,134,136I, 135Xe and 138Cs have been measured in the epi-cadmium neutron induced fission of 233U by using an off-line gamma-ray spectrometric technique. The average neutron energy of the epi-cadmium reactor neutron spectrum is 1.9 MeV. The root mean square fragment angular momenta (JRMS) were deduced from the IR values by using spin dependent statistical model analysis. The IR and JRMS values of considered fission products in the epi-cadmium neutron induced fission of 233U were compared with the literature data in the thermal neutron induced fission of 233U to examine the influence of excitation energy on nuclear structure effect.

In the epi-cadmium neutron induced fission of 238Pu, independent isomeric yield ratios (IR) of 128,130,132Sb, 131,133Te, 134,136I, 135Xe and 138Cs have been measured by using an off-line γ-ray spectrometric technique. The average neutron energy of the epi-cadmium reactor neutron spectrum is 1.9 MeV. From the IR values, root mean square fragment angular momenta (JRMS) were deduced by using spin dependent statistical model analysis. The JRMS values from the present work in the epi-cadmium neutron induced fission of 238Pu were compared with the literature data in the thermal neutron induced fission of 238Pu to examine the role of excitation energy. Effect of nuclear structure on JRMS values was examined.