An External Beam from the Cornell 10 GeV Synchrotron

The electron beam at the Cornell 10 GeV Synchrotron has been extracted using a quadrupole and octupole magnet to drive the beam into a half-integral stop band. Extraction is then effected by three septum magnets. An achromatic transport system delivers the external electron beam into either of two experimental areas producing a focused spot at the experimental target of the order of 1 millimeter square with a divergence of ± .3 milliradians. At 10 GeV an electron beam with an intensity of 2 × 1010 electrons per pulse and a duty factor of 10% has been obtained. Our extraction efficiency is 85% at 5 GeV and falls to 70% at 10 GeV. By using only the septa, up to 1% of the beam can be extracted without interfering with an internally made photon beam, thus allowing simultaneous use of external electron and photon beams.