Peggy, the SLAC polarized electron source

A high-intensity pulsed source of polarized electrons has been operating at the Stanford Linear Accelerator Center since November 1974. In its normal operating mode, the source, PEGGY, produces a longitudinal polarization of .85 at an intensity of 2.5 x 109 electrons per 1.6 μs pulse at a repetition rate of 180 pulses/sec. In its alternate mode PEGGY produces up to 9.15 x 109 electrons/pulse with a polarization of 0.35. Thus far PEGGY has been used in studies of Moller scattering at GeV energies, deep inelastic e-p scattering with a longitudinally polarized proton target, and parity nonconservation using deep inelastic e-p scattering with an unpolarized target