A PINHOLE ANALYZER FOR THE CHARACTERIZATION OF GYRATING ELECTRON BEAMS

DEVICES EMPLOYING HIGH ENERGY GYRATING ELECTRON BEAMS FOR GENERATING HIGH POWER MICROWAVE RADIATION AT CENTIMETER AND MILLIMETER WAVELENGTHS ARE FINDING GREATER AND GREATER USE IN MAJOR DOE SPONSORED RESEARCH. OF SPECIAL INTEREST, FOR EXAMPLE, IS THE IDEA OF USING GYROKLYSTRONS OPERATING AT 10 HZ TO REPLACE THE 3 HZ KLYSTRONS AT THE STANFORD LINEAR ACCELERATOR. THE HIGHER FREQUENCY IS EXPECTED TO INCREASE THE ELECTRON ENERGY GAIN PER UNIT LENGTH REQUIRED TO REACH TEV LEVELS. TO DATE, GYROKLYSTRON EXPERIMENTS HAVE NOT PERFORMED AS WELL AS PREDICTED BY THEORY. THE EFFICIENCY ISINVARIABLY LOWER THAN PREDICTED. THIS IS USUALLY ATTRIBUTEDTO ONE OR ANOTHER OF THE BEAM CHARACTERISTICS WHICH ARE ASSUMED TO BE DIFFERENT FROM THOSE REQUIRED BY THE THEORY. BECAUSE BEAM DIAGNOSTIC INSTRUMENTS ARE DIFFICULT TO BUILD AND INTERPRET, THE BEAM CHARACTERISTICS ARE NOT WELL KNOWN AND, THEREFORE, THE FAILURE OF THE EXPERIMENTS TO FOLLOW THEORY IS NOT WELL UNDERSTOOD. THE PRESENT PROJECT WILL DESIGN AN INSTRUMENT FOR CHARACTERIZING GYRATING ELECTRON BEAMS. BOTH THE BEAM GEOMETRY AND THE ELECTRON DISTRIBUTIONFUNCTION WILL BE MEASURED, PERMITTING A DETAILED COMPARISON BETWEEN EXPERIMENT AND THEORY. THE RESULT WILL BE A MORE RAPID PROGRESS IN THE DEVELOPMENT OF HIGH EFFICIENCY, HIGH POWER MICROWAVE TUBES. THE GOAL IS THE EVENTUAL CONSTRUCTION OF TWO OR THREE INSTRUMENTS CAPABLE OF MEASURING BEAMS USED IN DEVICES THAT GENERATE CENTIMETER TO MILLIMETER WAVELENGTH RADIATION. THE INSTRUMENTS WILL INTERFACE WITH EXPERIMENTS CURRENTLY IN PROGRESS AT VARIOUS DOE SUPPORTED LABORATORIES SCATTERED ABOUT THE COUNTRY.