Recirculation of the Slac Beam

The intent of this proposal is to boost the energy of the SLAC beam into the 40 GeV range by recycling the electrons through the accelerator for a second pass. In order to use the normal klystron repetition rate (360 pps), the beam must be stored for the entire interpulse period (2.8 ms). Storage would be achieved in a 6.9 km-long path extending over the entire length of the accelerator housing. The direction of the beam would be reversed in magnet loops located at the ends of the accelerator. Beam energy losses due to synchrotron radiation would be made up by a room temperature linac operating at the accelerator frequency (2856 MHz). At the end of the storage interval , corresponding to about 122 revolutions, the beam would be reinjected into the accelerator to be accelerated for a second time. The final energy would equal the sum of the energy during storage plus the energy gained on the second pass. The recirculator could also be used for high duty cycle (up to 7%j experiments at the recirculating energy by simply storing the beam and extracting about 1% of the electrons per revolution.