Hydrogen Recoils Research Articles

On the Collimation of Fast Neutrons

Several experiments have been carried out with a beam of neutrons produced by placing a thick wall of water in front of a neutron source and using a hole through the wall as a collimator. It has been observed with cloud chambers that while there are large numbers of hydrogen recoils produced with the chamber in the beam, the number and length are both greatly diminished if the chamber is moved out of the beam. It has also been observed that such a collimating system supplemented by lead shields to cut down y-radiation from the collimating screen, gives little ionization current when the chamber is taken out past the edge of the beam, compared to that produced in the beam.