Prinprint PFC/JA-83-17 VELOCITY DIAGNOSTICS OF MILDLY RELATIVISTIC, HIGH CURRENT ELECTRON BEAMS

We describe two diagnostic methods for measuring the velocity of mildly relativistic, high current electron beams. The first involves a measurement of the radial electrostatic potential and of the beam current and yields the time resolved, spatially averaged axial beam velocity v,,. The second requires a measurement of the beam cyclotron wavelength in the guiding magnetic field and yields the product yv,,, where y=(1-v/2-L/ 2and vi is the transverse beam velocity. By combining the two techniques we obtain v,, and v1 for a 0.4-1.2MV electron beam carrying a current of 1-2kA. Permanent address: Institute of Electronics, Academia Sinica, Beijing, People's Republic of China.