Search results for "Neutron cross section"
showing 9 items of 39 documents
Pre- and post-scission neutron emission in the reaction180Hf(40Ar, fission) atE lab=216 MeV
1996
Neutron and fission fragment spectra following the180Hf(40Ar,f) reaction atE lab=216MeV were measured. The following neutron total, pre- and post-scission multiplicities were extracted:M tot =7.2±1.3,M pre =2.7±0.9,M post =4.5±0.9. The average temperature parameters of the neutron spectra areT pre=(1.63±0.16) MeV andT post=(1.14±0.26)MeV. The mean total kinetic energy of the fission fragments is TKE=(166±10) MeV and the measured width is σTKE=17.3MeV. The width of the fragment mass distribution is σ A =18.3u. The same reaction was analyzed using a modified statistical code which includes nuclear dissipation effects and particle and γ-ray emission in the equilibrium compound nucleus state an…
Neutron capture cross sections for neutron-rich isotopes
1985
Average continuum (Hauser-Feshbach) and resonance (Breit-Wigner) neutron capture rates for neutron-rich isotopes, determined on the basis of recent experimental nuclear physics input parameters, are compared to earlier theoretical reaction rates commonly used in astrophysical model computations.
The role of target geometry in 14 MeV neutron capture cross-section measurements
1972
Abstract Some activation capture cross sections of 14.5 MeV neutrons have been measured by systematically varying the target geometry. In all cases, the results are found to strongly depend on the geometrical conditions, which implies that a large part of the activation capture cross sections reported earlier are in error. An investigation of a number of materials shows that aluminium gives rise to a fairly small fraction of secondary low-energy neutrons and is, therefore, suitable material for target holders. A thin air-cooled target head specially designed for reliable activation cross-section measurements has been constructed and tested.
Thermal neutron capture cross sections of tellurium isotopes
2003
New values for thermal neutron capture cross sections of the tellurium isotopes 122Te, 124Te, 125Te, 126Te, 128Te, and 130Te are reported. These values are based on a combination of newly determined partial g-ray cross sections obtained from experiments on targets contained natural Te and gamma intensities per capture of individual Te isotopes. Isomeric ratios for the thermal neutron capture on the even tellurium isotopes are also given.
Emission of neutrons and the neutron halo of $^{11}$Li
1991
The matter distribution of the neutron drip-line nuclei has been a subject of intense interest since pioneering radioactive-beam experiments at Berkeley1). Unusually large interaction cross-sections measured at relativistic energies for 11Li,14Be and 17B nuclei were translated into effective matter radii. It was found that these were significantly larger than for other p-shell nuclei. In particular, the root-mean-square (rms) mass radius of 11Li was found to be 3.2fm, which was considerably larger than the 2.4fm radius of 9Li. At the same time, no signatures for significant deformation of 11Li were found in measurements of electric quadrupole moment by means of laser spectroscopy2).
A facility for fast-neutron irradiations at Jyväskylä and its use for nuclide cross-section measurements in fission
2013
Abstract An efficient and reliable transport system for fast-neutron irradiations has been built at the Physics Department, Jyvaskyla, Finland. It is constructed from commercial bicycle components and is driven by a computer-controlled stepping motor. It can be operated in single or cyclic mode. The neutron irradiated targets are moved within 1.2 s (full stop to full stop) to a well-shielded position 3 m away where they can be removed or directly investigated by γ spectroscopy. The system has been built with the aim to experimentally verify the calculated production rates of neutron-rich nuclei in the SPIRAL2 uranium target. However, the facility can be used for various kinds of fast-neutro…
Constraining the spin-dependent WIMP-nucleon cross sections with XENON1T
2019
We report the first experimental results on spin-dependent elastic weakly interacting massive particle (WIMP) nucleon scattering from the XENON1T dark matter search experiment. The analysis uses the full ton year exposure of XENON1T to constrain the spin-dependent proton-only and neutron-only cases. No significant signal excess is observed, and a profile likelihood ratio analysis is used to set exclusion limits on the WIMP-nucleon interactions. This includes the most stringent constraint to date on the WIMP-neutron cross section, with a minimum of 6.3 × 10−42 cm2 at 30 GeV/c2 and 90% confidence level. The results are compared with those from collider searches and used to exclude new paramet…
Low-Intensity Neutron Emission from TiDx Samples Under Nonequilibrium Conditions
2001
Several experiments were performed that loaded titanium samples with deuterium from the gas phase, changed the temperature of the samples over a wide range, and monitored the neutron emission. Neutron emissions in very low intensity bursts, still significantly above the background, were recorded, revealing that low-energy nuclear reactions in condensed matter can be produced at a very low rate, which occasionally can be high enough to become detectable.
High yield neutron generator based on a high-current gasdynamic electron cyclotron resonance ion source
2015
In present paper, an approach for high yield compact D-D neutron generator based on a high current gasdynamic electron cyclotron resonance ion source is suggested. Results on dense pulsed deuteron beam production with current up to 500 mA and current density up to 750 mA/cm2 are demonstrated. Neutron yield from D2O and TiD2 targets was measured in case of its bombardment by pulsed 300 mA Dþ beam with 45 keV energy. Neutron yield density at target surface of 109 s 1 cm2 was detected with a system of two 3 He proportional counters. Estimations based on obtained experimental results show that neutron yield from a high quality TiD2 target bombarded by Dþ beam demonstrated in present work accele…