ERL 05-3 Energy Recovery LINAC; a Next Generation Source for Inelastic X-ray Scattering

The Energy Recovery LINAC (ERL) being developed at Cornell should be an excellent source for Inelastic X-ray Scattering (IXS) because it will permit long undulators to operate at high efficiency generating unprecedented spectral flux (photons/second/meV) and brilliance. We discuss several advantages of the ERL for inelastic x-ray scattering. Presented at 5 th International Conference on Inelastic X-ray Scattering, 2004 Energy Recovery LINAC; a Next Generation Source for Inelastic X-ray Scattering K.D. Finkelstein1, I.V. Bazarov1,2, M. Liepe2, Q. Shen1, D. Bilderback1, S. Gruner1, A. Kazimirov1 Cornell High Energy Synchrotron Source, Laboratory for Experimental Particle Physics Wilson Laboratory Cornell University, Ithaca, New York 14853 Abstract The Energy Recovery LINAC (ERL) being developed at Cornell should be an excellent source for Inelastic X-ray Scattering (IXS) because it will permit long undulators to operate at high efficiency generating unprecedented spectral flux (photons/second/meV) and brilliance. We discuss several advantages of the ERL for inelastic x-ray scattering.The Energy Recovery LINAC (ERL) being developed at Cornell should be an excellent source for Inelastic X-ray Scattering (IXS) because it will permit long undulators to operate at high efficiency generating unprecedented spectral flux (photons/second/meV) and brilliance. We discuss several advantages of the ERL for inelastic x-ray scattering. Introduction IXS experiments benefit when the highest possible spectral flux is delivered to a sample at an incident energy corresponding to backscattering from high-order reflections of diced crystal analyzers. To achieve meV spectrometer resolution incident energy must be above 20KeV[1]. Third generation synchrotron sources are enabling great progress in IXS, but are even better sources likely to be available in the near future? This paper discusses one new source, the ERL being planned at Cornell University[2]. The ERL is an attractive next generation source because it should generate unprecedented x-ray flux and brilliance while being compatible with most experiments performed at storage rings today. The ERL idea, first discussed in 1965[3], and described more recently in reference [4], utilizes a pulsed-laser driven photocathode to produce ultra bright electron pulses that are injected into a superconducting radio frequency linear accelerator (rfLINAC). The pulses are accelerated to energy ≥5GeV and pass ONCE through a ring-like array of bend magnets and insertion devices. Electrons return 180° out of temporal phase with the LINAC accelerating fields where energy is extracted and the beam dumped. RF cavity Ohmic losses are very small, less than 0.01% of the circulating energy. Most of the energy is then available to accelerate an interleaved train of bunches. The result is that electron energy is recycled while bunch phase space does not grow to storage ring dimensions[5].