Results 1 - 10 of 179907
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[en] The absolute total cross sections for np and pp scattering below 1000 MeV are determined based on partial-wave analyses (PWAs) of nucleon-nucleon scattering data. These cross sections are compared with the most recent ENDF/B-VII.0 and JENDL-3.3 data files, and the Nijmegen PWA. Systematic deviations from the ENDF/B-VII.0 and JENDL-3.3 evaluations are found to exist in the low-energy region. Comparison of the np evaluation with the result of most recent np total and differential cross section measurements will be discussed. Results of those measurements were not used in the evaluation database. A comparison was done to check a quality of evaluation and its capabilities to predict experimental observables. Excellent agreement was found between the new experimental data and our PWA predictions.
[en] The current status of cross section measurements for atomic inner-shell ionization by electron bombardment is reviewed. Inner shell ionization studies using electrons as projectiles compliment the similar studies being done with heavy particles, and in addition can provide tests of the theory in those cases when relativistic effects and exchange effects are expected to be important. Both total cross sections and recently measured differential cross sections will be discussed and compared with existing theories where possible. Prospects for further experimental and theoretical work in this area of atomic physics using small electron accelerators will also be discussed
[en] Complete text of publication follows. Within the framework of the international nuclear fusion and engineering project, ITER (International Thermonuclear Experimental Reactor) the World's largest and most advanced tokamak nuclear fusion reactor is currently being built at Cadarache in the south of France. The ITER project aims to make the long-awaited transition from experimental studies of plasma physics to full-scale electricity-producing fusion power plants. For the accurate simulation of the processes in the active fusion reactor, numerous atomic, molecular, nuclear and surface related data are required. Among other data, elastic cross sections of fusion related materials are also needed. In this work the total and angular differential elastic cross sections of hydrogen atoms for a wide range of incident electron energy were calculated We used the code described in Ref. , where the partial expansion method is applied to obtain the differential and total cross sections of the elastic scattering. The elastic scattering of relativistic particles is described by the direct f(θ) and spin-flip g(θ) scattering amplitudes. The relativistic differential cross section per unit solid angle is given by (1) dσe/dθ /f(θ)/2 + /g(θ)/2 where θ is the scattering angle. Details of the calculations can be found elsewhere. Figure 1. shows our results, where the angular differential elastic cross sections for incident electron energy between 100 eV and 100 keV is plotted. The bin size of the incident electron energy was 50 eV from 100eV to 1000 eV, 500 eV from 1 keV to 10 keV and it was 5 keV between 10 keV and 100 keV. The dominant contribution appears at forward scattering angles. The cross sections decrease significantly with increasing scattering angles. We also found that the higher incident electron energies correspond to lower cross sections. Further calculations are in progress for other target materials and the results will be published soon. Acknowledgements. This work, supported by the European Communities under the contract of Association between EURATOM-HAS, was carried out within the framework of the Task Force on Integrated Tokamak Modelling of the European Fusion Development Agreement.
[en] The formulation of the time-dependent close-coupling method is extended so that energy and angle differential cross sections for the double photoionization of helium may be obtained. The fully quantal method now yields absolute total integral, energy differential, and angle differential cross sections. A detailed comparison is made with the absolute synchrotron measurements of Braeuning et al (1998 J. Phys. B: At. Mol. Opt. Phys. 31 5149-60) for triple differential cross sections at 20 eV excess photon energy. The agreement between theory and experiment is excellent. (author). Letter-to-the-editor
[en] MiniBooNE reports the first absolute cross sections for neutral current single π0 production on CH2 induced by neutrino and antineutrino interactions measured from the largest sets of NC π0 events collected to date. The principal result consists of differential cross sections measured as functions of π0 momentum and π0 angle averaged over the neutrino flux at MiniBooNE. We find total cross sections of (4.76 ± 0.05stat ± 0.40sys) x 10-40 cm2/nucleon at a mean energy of < Eν> = 808 MeV and (1.48 ± 0.05stat ± 0.14sys) x 10-40 cm2/nucleon at a mean energy of < Eν> = 664 MeV for νμ and (bar ν)μ induced production, respectively. In addition, we have included measurements of the neutrino and antineutrino total cross sections for incoherent exclusive NC 1π0 production corrected for the effects of final state interactions to compare to prior results.
[en] SciBooNE is a neutrino and anti-neutrino cross-section experiment at Fermilab, USA. The SciBooNE experiment is summarized and two independent CCQE analyses are described. For one of the analyses, an absolute νμ-CCQE cross section in the neutrino energy region (0.6-1.6) GeV is shown and the technique developed for such a purpose is also explained. The total cross section measured over this energy range agrees well with expectations, based on the NEUT event generator and using a value of 1.21 GeV for the CCQE axial mass
[en] Total cross section (TCS) measurements for positron scattering from nitrogen dioxide (NO2) are presented in the energy range 0.2–40 eV. The TCS, the elastic integral and differential cross sections, and the integral cross section accounting of all the inelastic processes (including positronium formation) have also been computed using the independent atom model with screening corrected additivity rule (IAM-SCAR) for incident energies from 1 to 1000 eV. A qualitative level of agreement is found between the present TCS experiment and theory at the common energies. As no previous measurements or calculations for positron–NO2 scattering exist in the literature, we also computed the TCS for electron collisions with NO2 employing the IAM-SCAR method. A comparison of those results to the present positron cross sections and the earlier electron-impact data and calculations is provided. To investigate the role that chemical substitution plays in positron scattering phenomena, we also compare the present positron–NO2 data with the TCSs measured at the University of Trento for positron scattering from N2O and CO2. (paper)