Conversion of the 2.5 MV Super HILAC injector power supply from 5 mA to 50 mA for boron neutron capture therapy

Renewed interest by several major university medical centers (UCSF-Standford, UC-Davis) in conducting boron neutron capture therapy (BNCT) led to the investigation of converting the decommissioned 5 mA, 2.5 MV Super HILAC injector to a 50 mA, 2.5 MV proton accelerator for the generation of neutrons. The original high impedance shunt-fed multiplier has been converted to a 55 stage air-coupled transformer with much lower impedance driven by a 200 kW, 50 kHz oscillator. The proton beam will be transported by electrostatic quadrupoles (ESQ) acceleration column housed axially within the power supply stages and biased by connecting sequentially to the desired voltage. The pressure vessel which houses the 2.5 MV power supply and ESQ acceleration column has been moved near the patient treatment rooms in the Bevatron complex. As funds become available, we will finalize the design and assembly of all components required for the generation, transport and conversion of the proton beam to neutrons for patient treatment. Preliminary tests of the power supply and design of the ESQ column will be presented.