Generation and acceleration of high-charge short-electron bunches

We report experimental results on the high peak current electron beam generated at the Argonne Wakefield Accelerator facility for wakefield applications. The facility produces bunch charges in the range 15–100 nC by using a photocathode based RF electron gun. The energy of the beam is 14 MeV. Our measurements show that for bunches of 100 nC, the pulse length can be as short as 30 ps. A detailed systematic study of pulse length versus charge is reported, as well as comparisons with numerical simulations. Dark current beam loading in the high field RF gun is also discussed