Experimental characterization of the high-brightness electron photoinjector

Abstract

Operational experience of the emittance compensated photoinjector at the Brookhaven Accelerator Test Facility (ATF) is presented in this paper. The photoinjector has demonstrated the stability and reliability required for UV and X-ray FEL applications. The RF gun has been routinely running at more than 100 MV/m peak acceleration field; the laser system of the photoinjector has achieved 2% peak to peak energy stability, 0.5 % point stability and better than 2 ps timing jitter. The highest measured quantum efficiency of the Cu cathode is 0.05%. The electron beam bunch length was measured to be 10 ps using a linac RF phase scan. The normalized rms emittance for a 0.5 nC charge was measured, to be from 1 to 2 mm-mad, which agrees with PARMELA simulations.

Simulation of ultrashort electron pulse generation from optical injection into wake-field plasma waves

“…In the 2D simulation presented, this quantity had a value of 1-2 mm mrad, and was found to be constant over the simulation. The best rf guns have a value of ϳ1 mm mrad, on the same order of magnitude [25]. The previous set of simulations in [10] had Ќn = 0.3 mm mrad due to smaller volumes and larger accelerating fields.…”

“…One is based on a current experiment using an instability to generate electrons [8], the self-modulated laser wake-field accelerator (SMLWFA). The other comparison is a compilation of the references in [25]. Looking at these values it can be seen that LILAC compares well, with the exception of bunch number.…”

“…Therefore after some acceleration, the correlation between momentum and position appeared. This chirp opens the possibility of compressing the already short electron bunch by use of conventional electron-bunch compression techniques [24,25].…”

Comparison of experimental tests and theory for a rectangular two-channel dielectric wakefield accelerator structure

“…In that case, when a bunch with a small charge is produced by an rf photocathode gun, a validated model [30][31][32] is…”

Radiation sources and diagnostics with ultrashort electron bunches

“…1. Measurements were performed at the Accelerator Test Facility (ATF) [28] at Brookhaven National Laboratory (BNL), which provided 44 MeV electron bunches variable from 1-5 ps, with corresponding charge 100-400 pC, a few π mm.mrad normalized emittance and 0.7% full width energy spread. Incoherent radiation in the visible wavelengths (622 nm) was produced using the MIT microwiggler [29], which provided a 0.42 T peak on-axis field over 60 periods of 8.8 mm each.…”