High-Energy Neutron Beam of 45% Polarization

A beam of polarized neutrons has been produced by allowing the 164-Mev internal proton beam of the Harvard synchrocyclotron to strike a beryllium target. The neutrons produced in the forward direction are then polarized by scattering from carbon at 15°. When neutrons of energy greater than 110 Mev are selected by the detection process, an average beam energy of 124-Mev results. An intensity of 2.9×${10}^5$ neutrons/${\mathrm{in}.\mathrm{}}^2$ min through 2 in. by 6-in. collimator has been obtained, with a polarization 0.447±0.020. The shielding techniques are also discussed.