The bound and resonance states along with corresponding autoionization widths for nitrogen sulphide (NS) molecule are determined using electron NS\(^+\) cation scattering calculations. The ...calculations are performed for \(^2{\Sigma}^+\), \(^2{\Pi}\) and \(^2\Delta\) total symmetries using the ab initio R-matrix method for both bound and continuum states. Calculations are performed on a grid of 106 points for internuclear separations between 1.32 and 3 \(\AA\). The resonance states yield dissociative potential curves which, when considered together with their widths, provide input for models of different electron-cation collision processes including dissociative recombination, and rotational and vibrational excitation. Curves and couplings which will lead directly to dissociative recombination are identified.
Cross sections and rate coefficients for the Dissociative Recombination (DR) of the NS+ ion induced by collisions with low-energy electrons are reported for temperatures between 10 and 1000 K, ...relevant to a large range of interstellar cloud temperatures. Uncertainties are discussed for these rates. Comparisons are made with DR rates for the isovalent NO+ molecular ion which are found to be much faster. The present findings lead to a moderate dissociative reaction rate coefficient, smaller by a factor of 2 than the current estimates reported in the different kinetic databases for a temperature of 10 K. We consider that our rate coefficients obtained through multichannel quantum defect theory for NS+ are likely to be better than those displayed in the different kinetic databases.
Deep understanding of $\gamma$-ray production from the fast neutron reaction
in water is crucial for various physics studies at large-scale water Cherenkov
detectors. We performed test experiments ...using quasi-mono energetic neutron
beams ($E_n = 30$ and 250~MeV) at Osaka University's Research Center for
Nuclear Physics to measure $\gamma$-rays originating from the neutron-oxygen
reaction with a high-purity germanium detector. Multiple $\gamma$-ray peaks
which are expected to be from excited nuclei after the neutron-oxygen reaction
were successfully observed. We measured the neutron beam flux by using a liquid
scintillator for the cross section measurement. With a spectral fitting
analysis based on the tailored $\gamma$-ray signal and background templates, we
measured cross sections for each observed $\gamma$-ray component. The results
will be useful to validate neutron models employed in the on-going and future
water Cherenkov experiments.
Plasma Sources Sci. Technol. 27 (2018) 025015 (10pp) Multichannel quantum defect theory is applied in the treatment of the
dissociative recombination and vibrational excitation processes for the ...BeD$^+$
ion in the twenty four vibrational levels of its ground electronic state
($\textrm{X}\,{^{1}\Sigma^{+}},v_{i}^{+}=0\ldots 23$). Three electronic
symmetries of BeD$^{**}$ states (\ensuremath{^{2}\Pi},
\ensuremath{^{2}\Sigma^{+}}, and \ensuremath{^{2}\Delta}), are considered in
the calculation of cross sections and the corresponding rate coefficients. The
incident electron energy range is $10^{-5}$--2.7 eV and the electron
temperature range is 100--5000~K. The vibrational dependence of these
collisional processes is highlighted. The resulting data are useful in magnetic
confinement fusion edge plasma modelling and spectroscopy, in devices with
beryllium based main chamber materials, such as ITER and JET, and operating
with the deuterium-tritium fuel mix. An extensive rate coefficients database is
presented in graphical form and also by analytic fit functions whose parameters
are tabulated in the supplementary material.
Rate coefficients for dissociative recombination and state-to-state
rotational transitions of the D$_{2}^{+}$ ion induced by collisions with very
low-energy electrons have been reported following our ...previous studies on
HD$^{+}$ and H$_{2}^{+}$ 9,10. The same molecular structure data sets,
excitations ($N_{i}^{+} \rightarrow$ $N_{f}^{+}=N_{i}^{+}+2$ for $N_{i}^{+}=0$
to $10$) and de-excitations ($N_{i}^{+}$ $\rightarrow$ $N_{f}^{+}=N_{i}^{+}-2$,
for $N_{i}^{+}=2$ to $10$) were used for collision energies ranging from $0.01$
meV to $0.3$ eV. Isotopic effects for dissociative recombination and rotational
transitions of the vibrationally relaxed targets are presented.
Rate coefficients for the dissociative recombination, vibrational excitation and vibrational de-excitation of the BeT\(^{+}\) ion for all vibrational levels of its ground electronic state (\( ...X\ensuremath{^{1}\Sigma^{+}},v_{i}^{+}=0,\dots,27\)) are reported, including in the calculation the contribution of super-excited states of the BeT complex pertaining to three electronic symmetries - \(^{2}\Pi\), \(^{2}\Sigma^{+}\), and \(^{2}\Delta\). These data are suitable for the kinetic modeling of beryllium and tritium containing plasma, as encountered in magnetic fusion devices with beryllium walls (JET, ITER). In the present study we restrict ourselves to incident electron energies from 10\(^{-3}\) up to \(2.7\) eV, and to electron temperatures between \(100\) and \(5000\) K, respectively. Together with our earlier and closely related studies on the BeH\(^{+}\) and BeD\(^{+}\) systems, this present work completes the isotopic coverage for the beryllium monohydride ions. The vibrational energy (rather than the vibrational quantum state) is identified as a proper isotopic similarity parameter, e.g., for reduced but still isotopically correct plasma chemistry models.
The paper presents an important aspect concerning the control of the shaft rotating motion, using a DSP (digital signal processor) connected to a personal computer. It describes the general structure ...and the operating mode of a development system based on the floating point DSP96002 from Motorola, connected to an IBM PC computer. The information about rotating motion is taken over by two incremental rotation transducers and numerically processed by computer. The processing program provides results concerning the angular speed, the angular deviation, also calculates the Fourier transform of the angular speed and graphically displays the spectral components.
published in: Romanian Astron. J., 30, 101 (2020) We describe the major low-energy electron-impact processes involving H$^+_2$
and HD$^+$, relevant for the astrochemistry of the early Universe: ...Dissociative
recombination, elastic, inelastic and superelastic scattering. We report cross
sections and Maxwellian rate coefficients of both rotational and vibrational
transitions, and outline several important features, like isotopic, rotational
and resonant effects.
The ENUBET project is aimed at designing and experimentally demonstrating the concept of monitored neutrino beams. These novel beams are enhanced by an instrumented decay tunnel, whose detectors ...reconstruct large-angle charged leptons produced in the tunnel and give a direct estimate of the neutrino flux at the source. These facilities are thus the ideal tool for high-precision neutrino cross-section measurements at the GeV scale because they offer superior control of beam systematics with respect to existing facilities. In this paper, we present the first end-to-end design of a monitored neutrino beam capable of monitoring lepton production at the single particle level. This goal is achieved by a new focusing system without magnetic horns, a 20 m normal-conducting transfer line for charge and momentum selection, and a 40 m tunnel instrumented with cost-effective particle detectors. Employing such a design, we show that percent precision in cross-section measurements can be achieved at the CERN SPS complex with existing neutrino detectors.
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