Intense Neutron Source Development for Use in Cancer Therapy

A neutron production rate of 1.1 × 1011/s from the D(d,n)3He reaction has been measured from a 200 kV, 200 mA d. c. deuterium ion accelerator during the initial bombardment of a scandium deuteride target. Over a period of 40 h operation, the output decreased to 8 × 1010/s due to impurities in the ion beam being implanted in the target and displacing deuterium just below the target surface. Deuterium concentration depth profiles in the target have been measured which show the deuterium depletion near the surface. The initial neutron output scales to >1 × 10l3/s from the T(d,n)4He reaction for a D,T ion beam on a ScDT target, which is the output required for a clinically useful cancer therapy machine. Efforts to reduce the ion beam impurity content to acceptable levels will be evaluated in a new accelerator tube that is described.