Low noise electron gun with crossed electric and magnetic fields and auxiliary axial electric field

Claim 1

A MICROWAVE ELECTRON DISCHARGE DEVICE, COMPRISING: ELECTRON GUN MEANS FOR PRODUCING AN ELECTRON BEAM INCLUDING CATHODE MEANS HAVING A CYLINDRICAL SURFACE ABOUT A PREDETERMINED AXIS AND ACCELERATING ANODE MEANS SUBSTANTIALLY COAXIAL WITH SAID CATHODE MEANS AND FACING THE CYLINDRICAL SURFACE THEREOF, SAID CATHODE AND ANODE MEANS DEFINING AN ELECTRON GUN SPACE THEREBETWEEN, MEANS FOR PRODUCING WITHIN SAID SPACE A SUBSTANTIALLY RADIAL ELECTRIC FIELD AND A SUBSTANTIALLY AXIAL MAGNETIC FIELD, MEANS FOR ADDITIONALLY PRODUCING WITHIN THE SPACE A FURTHER AXIAL ELECTRIC FIELD COMPONENT, MEANS FOR EFFECTIVELY HEATING SAID CATHODE MEANS TO PRODUCE CATHODE EMISSION THEREFROM, GRID MEANS EXTENDING CLOSE TO THE SURFACE OF SAID CATHODE MEANS AND HAVING CONDUCTING ELEMENTS THEREOF SEPARATED FROM EACH OTHER BY A DISTANCE COMPRISED BETWEEN 1/3 AND 1/5 OF THE DISTANCE BETWEEN SAID CATHODE AND GRID MEANS, AND MEANS FOR CARRYING SAID GRID MEANS AT A POTENTIAL INTERMEDIATE THE POTENTIALS OF SAID ANODE AND CATHODE MEANS.