Experimental operation of a 17 GHz photocathode RF gun

S. Trotz, W. Brown, B. Danly, J.P. Hogge, K.E. Kreischer, M. Shapiro, R.J. Temkin
Proceedings of the 1997 Particle Accelerator Conference (Cat. No.97CH36167)  
Initial operation of a 17 GHz RF photocathode electron gun has been achieved at MIT. This is the first photocathode electron gun to operate at a frequency above 2.856 GHz. Such electron guns have the potential for achieving record high values of electron beam quality. The 1.5 cell, p-mode, copper cavity was tested with 5-10 MW, 100 ns, 17.145 GHz pulses from a klystron amplifier built by Haimson Research Corp. Conditioning resulted in a maximum surface field of 250 MV/m. Dark current of 0.5 mA
more » ... current of 0.5 mA was observed at 175 MV/m, consistent with Fowler-Nordheim field emission theory if a field enhancement factor of about 100 is assumed. Electron bunches were generated by a regenerative laser amplifier that produces 20-40 mJ UV pulses. Faraday cup measurements indicated 0.12 nC bunches were produced with a kinetic energy of about 1 MeV. This corresponds to a peak current of about 120 A, and a density at the cathode of 8.8 kA/cm 2 . Phase scans of laser induced emission reveal an overall phase stability of better than ±20°, corresponding to ±3 ps synchronization of the laser pulses to the microwave field. 2690 0-7803-4376-X/98/$10.00
doi:10.1109/pac.1997.752733 fatcat:lt763f4wcfhq3e6mtmemgmunpq