A X"LTIwIRE SECONDARY EMISSION PROFILE MONITOR FOR SMALL EMITTANCE BEAMS

A secor.dary emission monitor using two multiwire grids separated by a positively biased collector has been constr.Jcted and tested with a 1 GeV electron beam at the Orsay Linac. The monitor installed just before the electron-positron converter has 8 gold-plated-tung-sten wires of 0.1 mm diameter equally spaced C.2 mm apart in each plane. Each wire is connected with an integrator usinq a low-bias current cperational ampli-fier. The wire places and the collector are moved into the beam by a steppiny motor: that allows beam-position verification. We measured narrow profiles for 1 Am? peak current pulses of 30 nanoseconds width. Profiles are displayed on a scope and allow ernittance determina-tion ky the three gradient method. Sc;ch a monitor is very useful to control ti-.e electron beam position an