Fission-neutrons source with fast neutron-emission timing

Tagging fast neutrons from a 252Cf fission-fragment source.

Coincidence and time-of-flight measurement techniques are employed to tag fission neutrons emitted from a 252Cf source sealed on one side with a very thin layer of Au. The source is positioned within a gaseous 4He scintillator detector. Together with α particles, both light and heavy fission fragments pass through the thin layer of Au and are detected. The fragments enable the corresponding fis...

Neutrons and Neutron Generators

This article was originally intended as a brief introduction to the article by Richard Hull on the Farnsworth/Hirsch “fusor.” However, as there has been some interest by a number of subscribers in neutron generators, I decided to provide a somewhat more lengthy tutorial on the reactions that produce neutrons, some practical applications of neutrons, and a few of the various types of devices tha...

Multiple-wavelength neutron holography with pulsed neutrons

Local structures around impurities in solids provide important information for understanding the mechanisms of material functions, because most of them are controlled by dopants. For this purpose, the x-ray absorption fine structure method, which provides radial distribution functions around specific elements, is most widely used. However, a similar method using neutron techniques has not yet b...

Neutron lifetime measured with stored ultracold neutrons.

Limitations to presaddle neutron emission from fission-fragment charge distributions.

The e8'ect of including mass-asymmetry dependent 6ssion delay times into the statistical model has been investigated. The shape of the predicted charge distribution of fission fragments is found to be very sensitive to the magnitude and mass-asymmetry dependence of these delay times. Measured mass-asymmetry dependent prefission neutron multiplicities were fit with calculated presaddle values by...