High Current CW Superconducting RFQ Linac

THE EFFECTIVENESS OF THE NEUTRAL PARTICLE BEAM (NPB) MISSILE DEFENSE SYSTEM DEPENDS ON THE SUCCESSFUL ACCELERATION OF HIGH BRIGHTNESS H ION BEAMS AT HIGH CURRENTS WITH CONTINOUS WAVE (CW) OPERATION. PRESENT BASELINE DESIGNS FOR THESE POWERFUL LINAC SYSTEMS INCLUDE ONE OR MORE STAGES OF BEAM COMBINATION (FUNNELING) INTO LATER STAGES OF THE LINAC TO OVERCOME THE CURRENT LIMITATIONS OF THE INITIAL LINAC STAGE, THE RADIO FEQUENCY QUADRUPOLE (RFQ). HOWEVER, SEVERAL SDIO SYSTEM DESIGN CONTRACTORS HAVE SUGGESTED THAT THIS LIMITATION CAN BE OVERCOME WITH THE USE OF A SUPERCONDUCTING RFQ (SCRFQ) DESIGNED SPECIFICALLY FOR HIGH CURRENT. INITIAL RESULTS OF A SUPERCONDUCTING NIOBIUM STRUCTURE AT ARGONNE NATIONAL LABORATORY (ANL) SUGGEST THAT THE CURRENT LIMIT IN SUCH A DEVICE MIGHT BE AN ORDER OF MAGNITUDE GREATER THAN CONVENTIONAL RFQ DESIGNS. THE SUCCESSFUL DEVELOPMENT OF SUCH A HIGH CURRENT SCRFQ WILL NOT ONLY OFFER SIGNIFICANT ADVANTAGES FOR NPB SYSTEMS, BUTS FOR MEDICAL AND INDUSTRIAL APPLICATIONS REQUIRING HIGH CURRENT CW ION BEAMS AS WELL. THE OBJECTIVE OF THE PROPOSED PHASE I EFFORT WILL BE TO ESTABLISH THE PRACTICAL DESIGN CRITERIA FOR A HIGH CURRENT CW SCRFQ AND DEVELOP THE DESIGN TOOLS AND COMPUTER SIMULATION CODES NECESSARY TO COMPLETE A PROTOTYPE STRUCTURE CONCEPTUAL DESIGN. THIS STUDY WILL BE PERFORMED IN COLLABORATION WITH THE GROUP OF SUPERCONDUCTING NIOBIUM LINAC STRUCTURE EXPERTS AT ANL IN THE ENGINEERING PHYSICS GROUP. THE RESULTS WILL FORM A SOLID FOUNDATION FOR THE PHASE II FINAL DESIGN, FABRICATION AND TESTING OF A HIGH CURRENT SCRFQ PROTOTYPE.