62 research outputs found
Total Prompt Energy Release in the Neutron-Induced Fission of 235-U, 238-U, and 239-Pu
This study addresses, for the first time, the total prompt energy release and
its components for the fission of 235-U, 238-U, and 239-Pu as a function of the
kinetic energy of the neutron inducing the fission. The components are
extracted from experimental measurements, where they exist, together with
model-dependent calculation, interpolation, and extrapolation. While the
components display clear dependencies upon the incident neutron energy, their
sums display only weak, yet definite, energy dependencies. Also addressed is
the total prompt energy deposition in fission for the same three systems.
Results are presented in equation form. New measurements are recommended as a
consequence of this study.Comment: Accepted for publication in Nuclear Physics
Neutronic Design and Measured Performance of the Low Energy Neutron Source (LENS) Target Moderator Reflector Assembly
The Low Energy Neutron Source (LENS) is an accelerator-based pulsed cold
neutron facility under construction at the Indiana University Cyclotron
Facility (IUCF). The idea behind LENS is to produce pulsed cold neutron beams
starting with ~MeV neutrons from (p,n) reactions in Be which are moderated to
meV energies and extracted from a small solid angle for use in neutron
instruments which can operate efficiently with relatively broad (~1 msec)
neutron pulse widths. Although the combination of the features and operating
parameters of this source is unique at present, the neutronic design possesses
several features similar to those envisioned for future neutron facilities such
as long-pulsed spallation sources (LPSS) and very cold neutron (VCN) sources.
We describe the underlying ideas and design details of the
target/moderator/reflector system (TMR) and compare measurements of its
brightness, energy spectrum, and emission time distribution under different
moderator configurations with MCNP simulations. Brightness measurements using
an ambient temperature water moderator agree with MCNP simulations within the
20% accuracy of the measurement. The measured neutron emission time
distribution from a solid methane moderator is in agreement with simulation and
the cold neutron flux is sufficient for neutron scattering studies of
materials. We describe some possible modifications to the existing design which
would increase the cold neutron brightness with negligible effect on the
emission time distribution.Comment: This is a preprint version of an article which has been published in
Nuclear Instruments and Methods in Physics Research A 587 (2008) 324-341.
http://dx.doi.org/10.1016/j.nima.2007.12.04
Special orders no. 184, Major General Pleasonton, Army of the Potomac
The order discharges Private David McClure, Company E, 3rd Indiana Cavalry from service in the United States military to enable him to accept a commission in a newly created regiment.1860s (1860-1869)600ppiCivil War Military FrontDC046This Civil War Military Front collection was funded by LSTA
- …