AES, Princeton, New Jersey
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.
University of Tel-Aviv, Faculty of Engineering, Tel-Aviv
The cooperative spontaneous emission from a bunch of particulate dipole radiators (e.g. excited atoms) can be enhanced (super-radiance) or suppressed (sub-radiance) by proper phasing of the radiators[1] Analysis and 3-D simulation of collective interaction micro-dynamics in a drifting e-beam, reveal a process of homogenization of the particles distribution and suppression of the beam current shot-noise[2]. Consequently, such a beam would exhibit Dicke’s kind of spontaneous emission sub-radiance when injected into a FEL. With present state of the art technology, suppression and control of FEL SASE power can be attained at optical frequencies up to the UV. A theory will be presented on the implications of this beam noise control on the attainable coherence level of seed injected FELs. It is shown that when the beam current shot-noise is suppressed, the coherence of the FEL is limited by the beam energy spread. The fundamental theoretical limit of FEL coherence, analogously to conventional lasers[3], is found to be, the quantum noise limit. This would be attainable only if the beam energy spread can be reduced below the level of the photon emission energy.
[1] R. H. Dicke, Phys. Rev. 93, 99 (1954).
[2] A.Gover, E.Dyunin, Phys. Rev.Lett., {10}2, 154801, (2009).
[3] A.L.Schawlow and C.H.Townes, Phys. Rev., 112, 1940
FZD, Dresden
Ankara University, Faculty of Engineering, Tandogan, Ankara
To extend the wavelength range of possible experiments from the FIR into the THz region a dedicated beamline is planned at the ELBE Radiation Source. The beamline will deliver coherent transition radiation and coherent synchrotron radiation as broad-band (essentially single-cycle) radiation. Superradiant undulator radiation will be produced for a tunable narrow-band radiation source in the 100GHz to 3THz range. This requires a compression of the ELBE electron beam down to 150fs bunchlength. The beam transport and bunch compression scheme as well as the properties of the produced radiation are presented in detail.