Performance of the 2 MeV microwave gun for the SSRL 150 MeV linac

As described previously, the pre-injector linac for SSRL's 3 GeV synchrotron is fed by a 2 MeV, 1.5 A, low emittance microwave gun, consisting of a thermionic cathode mounted in the first cell of a 1-1/2-cell S-band cavity. In this article, the authors report the successful operation of the gun, the longitudinally-bunching α-magnet, and the three-microbunch FET-pulsed beam-chopper. Simulations predict a normalized rms emittance at the gun exit of < 10 π · mec · μm; chromatic effects in transport optics increase this to approx-lt 30 π · mec · μm. The gun has a longitudinal phase-space suited to magnetic compression, as a result of which they predict that peak currents > 300 A in a 1 ps bunch are feasible