Search

The 115In(n,2n)114mIn and 197Au(n,2n)196Au reaction cross sections have been measured relative to the 27Al(n,α)24Na monitor reaction at the two different incident neutron energies of 13.520 ± 0.005 MeV and 14.54 ± 0.24 MeV. The neutrons from the D-T fusion reaction at the Purnima neutron generator were used for activation followed by off-line γ-ray spectrometry. The uncertainty propagation and correlation of measured reaction cross sections were estimated using covariance analysis through considering the partial uncertainties in different attributes. The measured reaction cross sections from the present work have been compared with the literature data from EXFOR compilation, ENDF data of various libraries and theoretically calculated values from the TALYS-1.9 code.

The (n,2n) reaction cross sections of cerium isotopes have been experimentally measured at the neutron energy of 13.50 ± 0.15 MeV by using the method of activation and off-line γ-ray spectroscopy. The neutron energy was obtained from the D-T reaction using the Purnima Neutron Generator at BARC. The natCe sample was irradiated along with the gold and indium monitor foils. The cross sections of 140Ce(n,2n)139Ce and 142Ce(n,2n)141Ce reactions were measured by using both the gold and indium as a monitor and then collapsed to get the best values of reactions cross sections. The uncertainties in the measured cross sections of 140Ce(n,2n)139Ce and 142Ce(n,2n)141Ce reactions were determined using covariance analysis by considering uncertainties in various attributes. The measured values from the present work were compared with the literature data based on EXFOR compilation, evaluated data from different libraries and theoretically calculated values from TALYS-1.95 and EMPIRE-3.2.

The 67Zn(n,p)67Cu, 64Zn(n,2n)63Zn, 89Y(n,γ)90mY and 89Y(n,2n)88Y reaction cross sections relative to the 197Au(n,2n)196Au monitor reaction have been determined at the neutron energy of 14.54 ± 0.002 MeV by using the method of activation and off-line γ-ray spectrometry. The neutron energy used was obtained from the 3H(d,n)4He reaction. The covariance analysis was performed by taking the uncertainties arising in various attributes and the correlations between those attributes. The analyzed results from the present measurement were compared with the literature data and evaluated data of various libraries like ENDF/B-VIII, JEFF-3.3, JENDL-4.0 and ROSFOND-2010 libraries as well as with the calculated values based on TALYS-1.9 code.

The $$ ^{232} {\text{Th}}\left( {{\text{n}},2{\text{n}}} \right)^{231} {\text{Th}} $$ reaction cross sections were measured at the neutron energies of 10.49 ± 0.29, 14.46 ± 0.26, 18.36 ± 0.24 MeV and 15.03 ± 0.003 MeV. For the first three energies, $$ ^{7} {\text{Li}}\left( {{\text{p}},{\text{n}}} \right) $$ reaction as a neutron source at the BARC-TIFR Pelletron accelerator facility was used. For the latter energy, $$ ^{3} {\text{H}}\left( {{\text{d}},{\text{n}}} \right) $$ neutron source using the PURNIMA neutron generator facility was used. The experiments were carried out using the activation method and off-line $$ \upgamma $$ -ray spectrometric technique. Covariance information of various attributes of cross section was propagated to obtain the covariance matrix for the reaction cross sections. The experimental resuts obtained with reference to the two different neutron sources are then compared with the values of evaluated nuclear data files such as ENDF/B-VIII.0, JENDL 4.0, JEFF-3.2, ROSFOND-2010, TENDL-2017 and the theoretical values from TALYS-1.9 code.

The cross sections for the 93Nb(n,2n)92mNb, 93Nb(n,α)90mY and the 92Mo(n,p)92mNb reactions have been measured with respect to the 197Au(n,2n)196Au monitor reaction at the incident neutron energy of 14.78 ± 0.19 MeV by employing methods of activation and off-line γ-ray spectrometry. The covariance analysis was carried out by taking into consideration of partial uncertainties in different attributes and correlation among the attributes. The present data have been compared with the literature data available in EXFOR, evaluated data of different libraries and theoretical values based on TALYS-1.8 code.

The $${}_{ }^{ 2 3 2} {\text{Th(n, 2n)}}{}_{ }^{ 2 3 1} {\text{Th}}$$ reaction cross sections relative to the $${}_{ }^{ 2 3 2} {\text{Th}}$$ (n, f)97Zr monitor reaction at the effective neutron energies of 8.97 and 16.52 MeV have been measured by using the activation and off-line $$\gamma$$ -ray spectrometry. The neutron beams were generated from the $${}_{ }^{7} {\text{Li}}\left( {{\text{p}}, {\text{n}}} \right){}_{ }^{7} {\text{Be}}$$ reaction by using the proton beam energies of 11 and 18.8 MeV. Correction factors for the low energy neutrons were taken care by considering the thickness of sample and non mono-energetic neutrons. The covariance analysis in the uncertainty of the reaction cross section was carried out by using error propagation and micro-correlation technique. The present data were compared with the literature data, evaluated data and theoretical values based on TALYS-1.8 code.

The cross sections for the $^{232}\mathrm{Th}(n,\ensuremath{\gamma})$ reaction have been measured in the neutron energy range of 11--19 MeV by using activation and offline $\ensuremath{\gamma}$-ray spectrometric techniques. The neutrons of desired energy were obtained by the $^{7}\mathrm{Li}(p,n)$ reaction using a proton beam of 13--21 MeV from the 14UD BARC-TIFR Pelletron facility at Mumbai, India. The $^{232}\mathrm{Th}(n,\ensuremath{\gamma})$ reaction cross sections were calculated using the computer code talys-1.8. The uncertainties in the measurement have been studied using covariance analysis of the experimental data. The results from the present work have been compared with the evaluated data of ENDF/B-VII.1 and JENDL-4.0 as well as the theoretically calculated values based on talys-1.8, and were found to be in good agreement. The outcome of the present work is important for the development of future fast reactors and accelerator driven subcritical systems (ADSs).

The cross sections of the $^{186}\mathrm{W}(n,\ensuremath{\gamma})^{187}\mathrm{W}, ^{183}\mathrm{W}(n,p)^{183}\mathrm{Ta}$ and $^{154}\mathrm{Gd}(n,2n)^{153}\mathrm{Gd}, ^{160}\mathrm{Gd}(n,2n)^{159}\mathrm{Gd}$ reactions were measured at the neutron energies $5.08\ifmmode\pm\else\textpm\fi{}0.165, 8.96\ifmmode\pm\else\textpm\fi{}0.77, 12.47\ifmmode\pm\else\textpm\fi{}0.825$, and $16.63\ifmmode\pm\else\textpm\fi{}0.95\phantom{\rule{0.16em}{0ex}}\mathrm{MeV}$. Standard neutron activation analysis technique and off-line $\ensuremath{\gamma}$ ray spectrometry were used for the measurement and analysis of the data. Measurements were done in the energy range where few or no measured data are available. The results from the present work are compared with the literature data based on the EXFOR compilation. The experimental results are supported by theoretical predictions using nuclear modular codes TALYS 1.8 and EMPIRE 3.2.2. The predictability of different one-dimensional models available in TALYS 1.8 and Levden models in EMPIRE 3.2.2 were tested. A detailed comparison of experimental results with theoretical model calculations is made.