20 research outputs found
Measurement of the U fission cross section and angular distributions of fragments from fission of U and U in the neutron energy range of 0.3-500 MeV
The U fission cross section and the angular distributions of
fragments from fission of U and U were measured for incident
neutron energies from 0.3 MeV to 500 MeV on the time-of-flight spectrometer of
the neutron complex GNEIS at the NRC "Kurchatov Institute" -- PNPI. Fission
fragments were registered using position-sensitive low-pressure multiwire
counters. In the neutron energy range above 20 MeV, the angular distributions
of U fission fragments were measured for the first time. The fission
cross section of U was measured relative to the fission cross
section of U, which is an accepted international standard. The
obtained data are compared with the results of other experimental works.
Theoretical calculations of the fission cross section and the anisotropy of
angular distribution of fission fragments for the U reaction
performed within the framework of our approach are presented and discussed.Comment: 21 pages, 22 figures, revised version accepted for publication in
Phys. Rev.
A measurement of the differential cross section for the two-body photodisintegration of 3He at theta_LAB = 90deg using tagged photons in the energy range 14 -- 31 MeV
The two-body photodisintegration of 3He has been investigated using tagged
photons with energies from 14 -- 31 MeV at MAX-lab in Lund, Sweden. The
two-body breakup channel was unambiguously identified by the (nonsimultaneous)
detection of both protons and deuterons. This approach was made feasible by the
over-determined kinematic situation afforded by the tagged-photon technique.
Proton- and deuteron-energy spectra were measured using four silicon
surface-barrier detector telescopes located at a laboratory angle of 90deg with
respect to the incident photon-beam direction. Average statistical and
systematic uncertainties of 5.7% and 6.6% in the differential cross section
were obtained for 11 photon-energy bins with an average width of 1.2 MeV. The
results are compared to previous experimental data measured at comparable
photon energies as well as to the results of two recent Faddeev calculations
which employ realistic potential models and take into account three-nucleon
forces and final-state interactions. Both the accuracy and precision of the
present data are improved over the previous measurements. The data are in good
agreement with most of the previous results, and favor the inclusion of
three-nucleon forces in the calculations.Comment: 12 pages, 13 figures; further Referee comments addresse
Fission-Residues Produced in the Spallation Reaction 238U+p at 1 A GeV
Fission fragments from 1 A GeV 238U projectiles irradiating a hydrogen target
were investigated by using the fragment separator FRS for magnetic selection of
reaction products including ray-tracing and DE-ToF techniques. The momentum
spectra of 733 identified fragments were analysed to provide isotopic
production cross sections, fission-fragment velocities and recoil momenta of
the fissioning parent nuclei. Besides their general relevance, these quantities
are also demanded for applications. Calculations and simulations with codes
commonly used and recently developed or improved are compared to the data.Comment: 60 pages, 21 figures, 4 tables, 2 appendices (15 pages
Angular distributions and anisotropy of fission fragments from neutron-induced fission in intermediate energy range 1–200 MeV
Angular distributions of fission fragments from the neutron-induced fission of 232Th, 233U, 235U, 238U and 209Bi have been measured in the energy range 1–200 MeV at the neutron TOF spectrometer GNEIS based on the spallation neutron source at 1 GeV proton synchrocyclotron of the PNPI (Gatchina, Russia). The multiwire proportional counters have been used as a position sensitive fission fragment detector. A description of the experimental equipment and measurement procedure is given. The anisotropy of fission fragments deduced from the data on measured angular distributions is presented in comparison with experimental data of other authors, first of all, the recent data from WNR at LANSCE (Los Alamos, USA) and n_TOF(CERN)
Angular distributions and anisotropy of fission fragments from neutron-induced fission in intermediate energy range 1–200 MeV
Angular distributions of fission fragments from the neutron-induced fission of 232Th, 233U, 235U, 238U and 209Bi have been measured in the energy range 1–200 MeV at the neutron TOF spectrometer GNEIS based on the spallation neutron source at 1 GeV proton synchrocyclotron of the PNPI (Gatchina, Russia). The multiwire proportional counters have been used as a position sensitive fission fragment detector. A description of the experimental equipment and measurement procedure is given. The anisotropy of fission fragments deduced from the data on measured angular distributions is presented in comparison with experimental data of other authors, first of all, the recent data from WNR at LANSCE (Los Alamos, USA) and n_TOF(CERN)