General Description and Performance Measurements on Desy Linac II Electron-Positron Injector

Measurements made during acceptance testing of the Desy electron-positron linear accelerator Indicate performance approaching the design value. The purpose of the linac is high-current Injection to the 7 GeV synchrotron and future electron-positron Injection into a 3 GeV storage ring now under construction. The linac consists of 12 5.2 meter constant-gradient sections driven by SLAC-type (TV) klystrons operating at 24 MW. Electron pulsed currents of 135 mA at 514 MeV In a 1% energy bin were measured during 24-hour tests. A positron current of 1.4 mA within an energy spread(ΔE/E) of 1% bin and an emittance of 1π mRad.cm at 385 MeV has been measured. Electron load line and emittance data have been taken. Beampulse shortening of the SLAC-type occurs above 250 mA.