The External Electron Beam Facility at the Cambridge Electron Accelerator

The development of the resonant extraction technique has made possible the slow extraction of the internal beam from alternating gradient synchrotrons. An electron beam was extracted from the 6 Gev Cambridge Electron Accelerator in 1963, using this technique.1 Measurements of intensity and emittance confirmed the design calculations on the components of the extraction system. During 1964, the external beam facility was developed to a point where it is in routine use for high energy physics experiments. Some modifications were made to the components of the extraction system and a more complete study was made of its performance. Seventy per cent of the circulating beam is extracted with spill times up to 1 millisecond. Two beams are derived from the extracted beam and are transported by achromatic transport systems to different points on the experimental floor. Each transport system was designed in such a way as to minimize the radiation hazard which could be produced by the intense electron beam.