AN ION PROBE FOR TIGHTLY-FOCUSED CHARGED PARTICLE BEAMS

THIS PROJECT PLANS TO DEVELOP A NOVEL, NONPERTURBING DIAGNOSTIC TO MEASURE THE POSITION, RADIUS, LENGTH, AND/OR CHARGE DISTRIBUTION OF TIGHTLY-FOCUSED, CHARGED PARTICLE BEAMS. THIS DIAGNOSTIC EMPLOYS A LOW ENERGY ( 50 KEV), LOW CURRENT ( 1MUA) STREAM OF IONS TO PROBE THE CHARGED PARTICLE BEAM. THE PROBE IONS ARE INJECTED ACROSS THE PATH OF THE RELATIVISTIC BEAM AND ARE DEFLECTED BY THE ELECTROMAGNETIC FIELDS OF THE BEAM. THE DIRECTION AND MAGNITUDE OF THE DEFLECTION DEPENDS ON THE CURRENT, POSITION, DURATION, RADIUS, AND CHARGE DISTRIBUTION OF THE RELATIVISTIC BEAM. CONSEQUENTLY, BY A SUITABLE CHOICE OF OPERATING PARAMETERS, THE ION PROBE CAN RESOLVE SOME OR ALL OF THESE QUANTITIES. THIS TYPE OF DIAGNOSTIC CAN BE IMPLEMENTED IN A VARIETY OF ACCELERATORS. HOWEVER, THIS PROJECT IS PRIMARILY INTERESTED IN RADIO FREQUENCY (RF) ACCELERATORS AND TIGHTLY-FOCUSED (MICRON OR SUBMICRON DIAMETER) BEAMS, BECAUSE CONVENTIONAL DIAGNOSTICS ARE UNABLE TO ADEQUATELY RESOLVE THE MICROSCOPIC STRUCTURE OF THIS KIND OF BEAM. INITIAL CALCULATIONS HAVE DEMONSTRATED THAT THE ION PROBE CAN RESOLVE BEAM POSITION TO WITHIN <<1 MUM AND CAN ACCURATELY MEASURE MANY DETAILS OF THE CHARGE DISTRIBUTION. THE ENERGY OF THE PROBE IONS CAN BE ADJUSTED SO THAT THE DIAGNOSTIC OPERATES WITH HIGH RESOLUTION OVER A VERY BROAD RANGE OF RELATIVISTIC BEAM PARAMETERS. IN PHASE I OF THIS PROJECT DETAILED ANALYSES WILL BE PERFORMED TO DETERMINE THE OPERATING RANGE AND OPTIMUM PARAMETERS OF THE ION PROBE AND TO DEVELOP A DETAILED DESIGN OF THE DIAGNOSTIC. A PROTOTYPE WILL BE CONSTRUCTED AND TESTED AT AN EXISTING RF LINAC FACILITY DURING PHASE II.