Systematic study of the (n,2n) reaction cross section for 121Sb and 123Sb isotopes

The cross sections of the 121Sb(n,2n) 120Sbm and 123Sb(n,2n) 122Sb reactions were measured at 12.50, 15.79 and 18.87 MeV neutron energies relative to the standard 27Al(n,α) 24Na monitor reaction using neutron activation and offline γ-ray spectrometry technique. Irradiations of the samples were performed at the BARC-TIFR Pelletron Linac Facility, Mumbai, India. The quasi-monoenergetic neutron was generated via the 7Li(p,n) reaction. Statistical model calculations were performed by nuclear reaction codes TALYS (ver. 1.9) and EMPIRE (ver. 3.2.2) using various input parameters and nuclear level density models. The cross sections of the ground and the isomeric state as well as the isomeric cross section ratio were studied theoretically from reaction threshold to 26 MeV energies. The effect of pre-equilibrium emission is also discussed in detail using different theoretical models. The present measured cross section were discussed and compared with reported experimental data and evaluation data of the JEFF-3.3, ENDF/B-VIII.0, JENDL/AD-2017 and TENDL-2019 libraries. A detailed analysis of the uncertainties in the measured cross section data was performed using the covariance analysis method. Furthermore, a systematic study of the (n,2n) reaction cross section for 121Sb and 123Sb isotopes were also performed within 14-15 MeV neutron energies using various systematic formulae. This work helps to overcome discrepancies in Sb data and illustrate a better understanding of pre-equilibrium emission in (n,2n) reaction channel.

Insights into the structure and surface geology of balanced and retrodeformed geological cross sections from the Nizampur basin, Khyber Pakhtunkhwa, Pakistan

The current research work is an attempt to apply the basic geological procedures, methods of geological mapping, surface and subsurface interpretation and restoration of balanced and retrodeformed cross sections from the Nizampur basin, Khyber Pakhtunkhwa, Pakistan. The work also includes the documentation of several surface structural features, i.e., anticlines, synclines and different types of folds and faults exposed in the vicinity of study area. Four central thrust faults were recognized named as Kahi Thrusts along the cross sections. These thrust faults carried the older sequences of rocks over the younger sequences in different portion along the measured cross section. The folded and faulted rocks in the area show that stratigraphic framework comprises of Eocene, Paleocene, Cretaceous and Jurassic succession of rocks. There are Eocene rocks existing in the extreme South of the mapped area with addition of older Cretaceous and Jurassic succession and contains simple and large-scale folds, faults and back thrust. Two structural transect were mapped which encounter different folds and faults, i.e., X-sections AB oriented NS and CD oriented NE-SW. Restoration of the structural transects was calculated and assumed that at the formation of Main Boundary Thrust, the study area was exposed to the tectonic forces which prognosticated 19.5% shortening in rock sequences from Jurassic to Eocene succession along the measured cross section A_B.

Inner-Shell Photodetachment of Na− Using R-Matrix Methods

Inner-shell photodetachment of Na− near the L-edge threshold was investigated using the R-matrix method. Significant structure was found in the cross section, and this structure is shown to be related to the complicated correlated electron dynamics endemic in negative ions. Comparison with experiment suggests that the absolute values of the measured cross section might be too small by a factor of two.

A new empirical formula for cross-sections of (n,nα) reactions

Studies on the cross-sections of (n,n[Formula: see text]) reactions which are energetically possible, about 14 MeV neutrons are quite scarce. In this paper, the cross-sections of (n,n[Formula: see text] nuclear reactions at [Formula: see text]14–15 MeV are analyzed by using a new empirical formula based on the statistical theory. We show that neutron cross-sections are closely related to the [Formula: see text]-value of nuclear reaction, in particular for (n,n[Formula: see text]) channels. Results obtained with this empirical formula show good agreement with the available measured cross-section values. We hope that the estimations on the cross-sections using the present formalism may be helpful in future studies in this field.

Measurement of the muon neutrino charged-current cross sections on water, hydrocarbon and iron, and their ratios, with the T2K on-axis detectors

We report a measurement of the flux-integrated $\nu_{\mu}$ charged-current cross sections on water, hydrocarbon, and iron in the T2K on-axis neutrino beam with a mean neutrino energy of 1.5 GeV. The measured cross sections on water, hydrocarbon, and iron are $\sigma^{\rm{H_{2}O}}_{\rm{CC}} = (0.840\pm 0.010(\mathrm{stat.})^{+0.10}_{-0.08}(\mathrm{syst.}))\times10^{-38}\,\mathrm{cm}^2$/nucleon, $\sigma^{\rm{CH}}_{\rm{CC}} = (0.817\pm 0.007(\mathrm{stat.})^{+0.11}_{-0.08}(\mathrm{syst.}))\times10^{-38}\,\mathrm{cm}^2$/nucleon, and $\sigma^{\rm{Fe}}_{\rm{CC}} = (0.859\pm 0.003(\mathrm{stat.})^{+0.12}_{-0.10}(\mathrm{syst.}))\times10^{-38}\,\mathrm{cm}^2$/nucleon, respectively, for a restricted phase space of induced muons: $\theta_{\mu}<45^{\circ}$ and $p_{\mu}>$0.4 GeV/$c$ in the laboratory frame. The measured cross section ratios are ${\sigma^{\rm{H_{2}O}}_{\rm{CC}}}/{\sigma^{\rm{CH}}_{\rm{CC}}} = 1.028\pm 0.016(\mathrm{stat.})\pm 0.053(\mathrm{syst.})$, ${\sigma^{\rm{Fe}}_{\rm{CC}}}/{\sigma^{\rm{H_{2}O}}_{\rm{CC}}} = 1.023\pm 0.012(\mathrm{stat.})\pm 0.058(\mathrm{syst.})$, and ${\sigma^{\rm{Fe}}_{\rm{CC}}}/{\sigma^{\rm{CH}}_{\rm{CC}}} = 1.049\pm 0.010(\mathrm{stat.})\pm 0.043(\mathrm{syst.})$. These results, with an unprecedented precision for the measurements of neutrino cross sections on water in the studied energy region, show good agreement with the current neutrino interaction models used in the T2K oscillation analyses.

Absolute ozone absorption cross section in the Huggins Chappuis minimum (350–470 nm) at 296 K

We report the ozone absolute absorption cross section between 350–470 nm, the minimum between the Huggins and Chappuis bands, where the ozone cross section is less than 10−22 cm2. Ozone spectra were acquired using an incoherent broadband cavity enhanced absorption spectrometer, with three channels centered at 365, 405, and 455 nm. The accuracy of the measured cross section is 4–30%, with the greatest uncertainty near the minimum absorption at 375–390 nm. Previous measurements vary by more than an order of magnitude in this spectral region. The measurements reported here provide much greater spectral coverage than the most recent measurements. The effect of O3 concentration and water vapor partial pressure were investigated, however there were no observable changes in the absorption spectrum most likely due to the low optical density of the complex.

Absolute ozone absorption cross section in the Huggins Chappuis minimum (350–470 nm) at 296 K

We report the ozone absolute absorption cross section between 350–470 nm, the minimum between the Huggins and Chappuis bands, where the ozone cross section is less than 10−22 cm2. Ozone spectra were acquired using an incoherent broadband cavity enhanced absorption spectrometer, with three channels centered at 365, 405, and 455 nm. The accuracy of the measured cross section is 2 %. Previous measurements vary by more than an order of magnitude in this spectral region. The measurements reported here provide much greater spectral coverage than the most recent measurements. We report a minimum absorption cross section of 3.4×10−24 cm2 at 381.8 nm, which is 22 % lower than the previously reported value. The effect of O3 concentration and water vapor partial pressure were investigated, however there were no observable changes in the absorption spectrum most likely due to the low optical density of the complex.

Mobile mini-DOAS measurement of the emission of NO₂ and HCHO from Mexico City

We here present the result of one mobile measurement using two ground based zenith viewing Differential Optical Absorption Spectroscopy (DOAS) instrument performed in a cross-section of the plume from the MCMA on the 10 March 2006 as part of the MILAGRO field campaign. The two instruments operated in the UV and the visible wavelength region respectively and have been used to derive the differential vertical columns of HCHO and NO2 above the measurement route. Using a mass-averaged wind speed and wind direction from the WRF model the instantaneous flux of HCHO and NO2 has been calculated from the two measurements and the results compared to the CAMx chemical model. The calculated flux through the measured cross-section was 1.9 (1.5–2.2) kg/s of HCHO and 4.4 (4.0–5.0) kg/s of NO2 using the UV instrument and 3.66 (3.63–3.73) kg/s of NO2 using the visible light instrument. The comparison with modeled values from CAMx shows a good agreement for the outflow of both NO2 and HCHO at this occasion.