AES, Medford, NY
EPIC Consulting, Medford, New York
Douglas Consulting, York, Virginia
FHI, Berlin
STI, Washington
Kevin Jordan PE, Newport News, Virginia
HZDR, Dresden
FZD, Dresden
The Fritz Haber Institute of the Max Planck Society in Berlin, Germany will celebrate its Centennial in 2011. Coincident with this event, they will christen a THz Free Electron Laser (FEL) that will operate from 3 to 300 microns. A linac with a gridded thermionic gun is required to operate from 15 to 50 MeV at 200 pC while delivering a transverse rms emittance of 20 mm-mrad in a 1 psec rms, 50 keV rms energy spread bunch at the wigglers. Mid-IR and far-IR wigglers enable this electron beam to deliver the required radiation spectrum. In addition to the longitudinal emittance, a key design requirement is the minimization of the micropulse and macropulse jitter to ensure radiation wavelength stability and timing consistency for pump probe experiments. We present the completed physics and engineering design that delivers the required performance for this device. Shipment is scheduled for the end of the calendar year and the status of fabrication will be summarized.
SLAC, Menlo Park, California
Electron source and gun technology by its nature is a multi-disciplined endeavor requiring knowledge of beam dynamics with RF fields, static fields and space charge forces as well as the chemistry and surface science related to electron emission and ultra-high vacuum. The need for a broad range of disciplines results because the electrons undergo a sequence of processes involving emission, acceleration and optical matching. This talk describes the physical process of each step with the goal of estimating its lowest possible contribution to the total emittance. The physics of electron emission, space charge forces, and the electron optics of the RF and magnetic fields will be developed and the emittance growth assessed for the gun and low energy portion of the injector. The thermal emittance and other properties of metal and semi-conductor cathodes are briefly reviewed, and the affect these properties have upon the limiting emittance and the gun design will be summarized. And finally, the space charge emittance compensation technique and the Ferrario matching criteria for the booster linac are discussed and critiqued for their emittance limits.
SLAC, Menlo Park, California
LLNL, Livermore, California
The Linac Coherent Light Source (LCLS) is a Free Electron Laser (FEL) operating with a fundamental wavelength ranging from 1.5-0.15 nm. Characterization of the higher harmonics present in the beam is important to users, for whom harder X-rays can either extend the useful operating wavelength range or represent a background to measurements. We present here measurements of the power in both the second and third harmonics.
SLAC, Menlo Park, California
The Linac Coherent Light Source at SLAC is a hard X-ray FEL which was designed for single electron bunch operation. Although most user experiments are not interested in multiple bunches from an S-band linac due to their short (ns) separation, there are some advantages with multi-bunch operation. Starting with two bunches where the delayed light of one bunch is used to seed the light of a second bunch, to many more bunches to increase the likelihood of rare target collisions, multi-bunch operation would open more options for the LCLS. In the past the SLAC Linac has operated with a few dedicated bunches for the SLC (Stanford Linear Collider), and up to 1400 bunches for some fixed target experiments, so a few bunches for the LCLS seems possible even with the original single bunch design. This paper will describe how the current RF implementation supports multi-bunch operation. Initial experimental tests with two bunches are presented.