Instrumentation for Monitoring Current from a 30 MeV Electron Linac

Non-intercepting monitors for measuring the total current or charge passing down the electron drift tubes have been constructed which are suitable for electron pulses from about 50 nanoseconds to 3.5 microseconds in width. Measurements are derived from output signals which are tuned to frequencies in the range 250 kcs to 45 kcs. Alternatively, for viewing pulse envelopes, ferrite coil outputs are integrated by a 25 ohm termination. The monitors are calibrated using an air cooled Faraday cup which is described.