Time-resolved beam profile measurements on the experimental test accelerator (ETA)

Examples are given of time-resolved beam profiles measured on ETA using several techniques. One method uses a Faraday cup that is remotely movable in two-transverse dimensions (x, y). The beam electrons passing through a small-diameter ho1e are collected on the center conductor of an e1ectrically open 50 ohm coax i a1 transmission line. The collector is in vacuum and gas is excluded by a thin foil. In another method a small diameter wire or pellet target is moved across the beam and the bremsstrahlung x-ray intensity is plotted. Data for these methods are recorded using a Tektronix 7912 digitizer at 16 equally spaced times during 50 ns. These methods require moving through nearly identica1 beam pu1ses.. Three other methods use a time gated (4 ns) microchanne1 plate television camera to record a two-dimensional image of the beam intensity on a single pulse. The light sources used for imaging are: Cherenkov light from a Kapton foil, prompt visible light from a titanium foil and radiated light from gas molecules excited by the beam. The time histories of these optical emissions are measured using microchanne1 plate detectors having time resolution < 1 ns. We are also testing an x-ray pi nho1e camera using Kα x-rays from tungsten.