A NEW ELECTROSTATIC ACCELERATOR FOR POSITRON EMISSION TOMOGRAPHY

THE OBJECTIVE OF OUR PROJECT IS TO DEVELOP NEW MEANS OF PRODUCING SHORT LIVED RADIOISOTOPES FOR POSITRON EMISSION TOMOGRAPHY (PET). THIS MEDICAL DIAGNOSTIC TECHNIQUE IS CAPABLE OF DISCERNING AND IMAGING MEDICALLY INTERESTING PHENOMENA, SUCH AS THE ACTIVITY OF VARIOUS PARTS OF THE BRAIN, OXYGEN FLOW IN THE BODY, AND OTHER QUANTITIES WHICH ARE IMPOSSIBLE TO DETERMINE BY ANY OTHER DIAGNOSTIC TECHNIQUE. IN THIS PROPOSAL, WE SHOW THAT HIGH ELECTROSTATIC VOLTAGES CAN BE PRODUCED BY PLACING HIGH VOLTAGE MODULES INSIDE ONE ANOTHER WITH THE HIGH VOLTAGE CONNECTION SUPPLIED BY THE BEAM ITSELF. MOTIVE POWER IS SUPPLIED TO THE INDIVIDUAL STAGES BY AN AIR CORE TRANSFORMERTECHNIQUE. ISOLATION BETWEEN STAGES IS ASSURED BY THE ENCLOSED NATURE OF THE CONFIGURATION. WE EFFECTIVELY HOUSE EACH 60 KV ACCELERATING STAGE INSIDE ITS OWN FARADAY CAGE. THESE CAGES ARE 'NESTED' INSIDE OF ONE ANOTHER, AND THEY IN TURN, FORM A PARTIALLY COMPLETE FARADAY CAGE WHICH ALLOWS PENETRATION OF MAGNETIC FIELDS FOR THE TRANSFORMER ACTION. BY USING RESONANT CIRCUITS, TRANSISTOR SWITCHING TECHNIQUES CAN BE USED TO SUPPLY THE POWER TO THE SECONDARIES EVEN WHEN THE TRANSFORMER COUPLING IS EXTREMELY LOW. INSIDE EACH NEST, WE HAVE A MULTI-TURN SECONDARY WINDING, A 3:1 VOLTAGE MULTIPLIER (SIMILAR TO A TELEVISION VOLTAGE MULTIPLIER) AND OVERVOLTAGE PROTECTION CIRCUITS. BYUSING A NEGATIVE ION SOURCE AND A STRIPPING FOIL, WE CAN RUN THE ACCELERATOR IN A TANDEM CONFIGURATION. OUR OVERALL GOALS ARE THE PRODUCTION OF .8 MEV,.4 MA DEUTERON BEAMS IN PHASE I.