Use of an Isochronous Cyclotron for Neutron Tie-of-Flight Experimentation

The design of the U. S. Naval Radiological Defense Laboratory´s (USNRDL) cyclotron for the production of subnanosecond, high intensity, charged particle beam pulses for neutron time-of-flight experiments, is described. Klystron bunching of the extracted cyclotron beam is possible for short bunching path lengths between cyclotron and target but it demands a beam of large energy spread -- greater than 1%. A method of linearizing the effect of the sinusoidally varying, accelerating potential is described, and it is shown that klystron beam bunching is possible with reduced beam energy spread. It is seen that the cyclotron competes with single stage, dc accelerators for neutron time-of-flight experimentation and will furnish large beam currents at higher energies in excess of the beam currents contemplated for the dc tandem machines.