LBNL, Berkeley, California, USA
A high-repetition rate (MHz-class), high-brightness electron beam photo-gun is under construction at Lawrence Berkeley National Laboratory in the framework of the Advanced Photo-injector EXperiment (APEX). The injector gun is based on a normal conducting 187 MHz RF cavity operating in CW mode. In its first operational phase it will deliver short bunches (~ 1 to tens of picoseconds) with energy of 750keV, and bunch charges ranging from 1pC to 1nC. Different high efficiency cathode materials will be tested, and the beam quality will be studied as a function of parameters as charge, initial bunch length and transverse size, focusing strength. Both the laser and electron beam diagnostics have been designed to assure the needed flexibility. In particular a high-resolution electron diagnostic section after the photo-gun provides the necessary dynamical range for scanned beam parameters: energy and energy spread, charge and current, transverse and longitudinal phase spaces, slice properties. The photo-gun electron beam diagnostic layout is presented, and the hardware choices, resolution and achievable dynamical ranges are also discussed.
LBNL, Berkeley, California, USA
ANL, Argonne, USA
We report on on-going studies of a superconducting CW linac driver intended to support a high repetition rate FEL operating in the soft x-rays spectrum. We present a point-design for a 1.8 GeV machine tuned for 300~pC bunches and delivering low-emittance, low-energy spread beams as needed for the SASE and seeded beamlines.
LBNL, Berkeley, California, USA
In this paper, we will present the status of the beam dynamics simulations for a Next Generation Light Source (NGLS) injector, based on a high repetition rate (1 MHz), high brightness design. A multi-stage beam compression scheme is proposed, based on the concepts of velocity bunching and emittance compensation. For the optimization of the design parameters we use a genetic algorithm approach, and we focus on a mode providing charges of 300 pC, with normalized transverse emittance less than 0.6 microns, suitable to operate a next generation light source based on an X-ray FEL. In addition, we discuss the effects of bunch compression and linearity of the transverse and longitudinal phase space of the beam.
LBNL, Berkeley, California, USA
UCB, Berkeley, California, USA
ANL, Argonne, USA
The Next Generation Light Source (NGLS) is a design concept, under development at LBNL, for a multi‐beamline soft x‐ray FEL array powered by a 2 GeV superconducting linear accelerator, operating with a 1 MHz bunch repetition rate. The CW superconducting linear accelerator is supplied by a high-brightness, high-repetition-rate photocathode electron gun. Electron bunches are distributed from the linac to the array of independently configurable FEL beamlines with nominal bunch rates up to 100 kHz in each FEL, and with even pulse spacing. Individual FELs may be configured for EEHG, HGHG, SASE, or oscillator mode of operation, and will produce high peak and average brightness x-rays with a flexible pulse format, and with pulse durations ranging from sub-femtoseconds to hundreds of femtoseconds.
