DEVELOPMENT OF A RADIO FREQUENCY QUADRUPOLE-FOCUSED DRIFT TUBE LINAC STRUCTURE

A NEAR LINEAR ACCELERATOR (LINAC) STRUCTURE WILL BE IDENTIFIED AND INVESTIGATED IN PHASE I AS A POSSIBLE EXTENSION TO THE FAMILY OF STRUCTURES NOW USED FOR ACCELERATION OF CHARGED PARTICLE BEAMS. A CANDIDATE STRUCTURE HAS BEEN IDENTIFIED; OTHERS MAY BE IDENTIFIED IN THE COURSE OF THE INVESTIGATION. THE IDENTIFIED STRUCTURE UTILIZES A FOUR-FINGERED GEOMETRY TO PRODUCE RADIO FREQUENCY (RF) ELECTRIC QUADRUPOLE FIELDS TO FOCUS THE BEAM. IT RESEMBLES A DRIFT TUBE LINAC (DTL) STRUCTURE WITH RADIO FREQUENCY QUADRUPOLE (RFQ) FOCUSING, THEREBY OPENING THE POSSIBILITY OF HIGHER FREQUENCY AND HIGH GRADIENT OPERATION. INCLUDED IN THE INVESTIGATIONS OF THE RFQ-DTL STRUCTURE WILL BE DETAILED ANALYSIS OF THE RF FIELDS SURROUNDING THE FOUR-FINGER ELECTRODES AND THE EFFECT OF THOSE FIELDS ON THE PARTICLE BEAMS PASSING THROUGH THEM. ISSUES SUCH AS THE RF EFFICIENCY OF THE STRUCTURE, THE STABILITY OF THE FIELDS WITH THE STRUCTURE, METHODS OF FABRICATION, AND METHODS OF EXCITATION WILL BE ADDRESSED. MODELS OF SOME CRITICAL COMPONENTS AND/OR ASSEMBLIES WILL BE FABRICATED FOR EVALUATION. THE ROLE OF THIS NEW STRUCTURE AND ITS IMPACT ON ACCELERATOR TECHNOLOGY WILL BE IDENTIFIED.