Current Strip for Extraction of the CEA External Electron Beam

The method presently being employed for extraction of 6 GeV electrons at the Cambridge Electron Accelerator is briefly described. The major element is a current strip, situated close to the orbit inner radius, which acts both as a non-linear focusing element and a magnetic deflector. Major characteristics of the current strip are: long pulse, 60 cycle, 6 GeV operation with an rms current density of 56,000 amperes per square inch at a maximum temperature of 135°F; minimum susceptibility to radiation damage, mechanical distortion and gas evolution; and reproducible remote positioning. As a result of experiments carried out with this current strip, modifications are under consideration which would make the extraction of other beams practicable, and would eliminate the need for a supportive downstream extraction magnet. A brief discussion of the modifications is included.