Beam Microstructure - Does it Affect Ferrite-Loaded Current Monitors?

Questions have been raised as to whether the current calibration of a ferrite-loaded toroid using a pulser is also valid for a linac beam with 1300 MHz microstructure. Three experiments will be reported; (1) a comparison of a ferrite toroid and a precision Faraday cup by a nulling experiment, (2) a comparison of a ferrite toroid and a Faraday cup using a special calibration technique, and (3) a direct comparison of a ferrite-loaded and an air-core toroid. The evidence is that the error, if present, is under 1 percent. Systematic errors due to beam-induced microwaves will be discussed.