Operation of a 4 ma Dynamitron as a Monoenergetic Neutron Source

The Cornell Dynamitron is being used as a source of monoenergetic neutrons in the range 30-500 keV, with fluxes up to 109 n/sr/s. Problems of generating and handling the 2 Mev, 4 ma beam are discussed. Analyzing magnet slit feedback is essential for accurate control of neutron energy. Contrary to other published data for these machines, we observe up to 3% drift in the energy when it is controlled by the voltage feedback system. Discrepancies between this and previously published data are discussed.