BEAM INSTRUMENTATION FOR THE COSY ELECTRON COOLER

The report deals with beam instrumentation of the electron cooler for COSY storage ring. The electron cooler is an electrostatic accelerator designed for beam energy up to 2 MeV and electron current up to 3 A in energy recovery mode. The electron beam is immersed in longitudinal magnetic field so the electron motion is strongly magnetized. The control electrode in the electron gun is composed of four electrically isolated sectors. Applying AC voltage to one sector allows tracing of motion of that particular part of the beam. The electron beam shape is registered with the combination of 4-sector electron gun and the BPMs. This method allows observing both dipole and quadruple (galloping) modes of electron beam oscillation. Compass probe for measuring and tuning the direction of magnetic field in the cooling section is described. A monitor based on a few small Faraday cups for measuring the electron beam profiles is presented.