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WEOAI1 |
Controlling the Emittance Partitioning of High-Brightness Electron Beams |
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- B.E. Carlsten, K. Bishofberger, L.D. Duffy, M.A. Holloway, Q.R. Marksteiner, N.A. Yampolsky
LANL, Los Alamos, New Mexico, USA
- R.D. Ryne
LBNL, Berkeley, California, USA
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High-brightness photoinjectors tend to produce electron beams with equipartitioned emittances, where the transverse emittances are roughly the same as the longitudinal emittance. However, the needs of next generation X-ray free-electron lasers (XFELs) will require transverse emittances up to three orders of magnitude smaller than the longitudinal emittances. Recent work on exotic optic schemes such as flat-beam transforms (FBTs) and emittance exchangers (EEXs) has pointed to significant new opportunities for providing arbitrary control of the beam emittance partitioning. Specifically, we can use initial correlations imposed on the beam as it is formed to control the beam’s eigen-emittances, which can then be recovered later at high energy as the actual beam emittances, in a linear sense. Here we discuss FBTs, EEXs, and other, more general, schemes to arbitrarily control the eigen-emittances, including the use of nonsymplectic beamline elements after the beam has been accelerated.
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Slides WEOAI1 [1.916 MB]
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| WEOA2 |
SASE FEL Pulse Duration Analysis from Spectral Correlation Function |
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- A.A. Lutman, Y.T. Ding, Y. Feng, Z. Huang, J. Krzywinski, M. Messerschmidt, J. Wu
SLAC, Menlo Park, California, USA
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Funding: Work supported by U.S. Department of Energy, Office of Basic Energy Sciences, under Contract DE-AC02-76SF00515.
A new method to measure the X-rays pulse duration through the analysis of the statistical properties of the SASE FEL spectra has been developed. The information on the pulse duration is contained in the correlation function of the intensity spectra measured after a spectrometer. The spectral correlation function is derived analytically for different profile shapes in the exponential growth regime and issues like spectral central frequency jitter and shot by shot statistical gain are addressed. Numerical simulations will show that the method is applicable also in saturation regime and that both pulse duration and spectrometer resolution can be recovered from the spectral correlation function. The method has been experimentally demonstrated at LCLS, measuring the soft X-rays pulse durations for different electron bunch lengths, and the evolution of the pulse durations for different undulator distances. Shorter pulse durations down to 13 fs FWHM have been measured using the slotted foil.
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Slides WEOA2 [0.758 MB]
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| WEOA3 |
Proof-of-principle Experiment for FEL-based Coherent Electron Cooling |
322 |
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- V. Litvinenko, S.A. Belomestnykh, I. Ben-Zvi, J.C. Brutus, A.V. Fedotov, Y. Hao, D. Kayran, G.J. Mahler, A. Marusic, G.T. McIntyre, W. Meng, M.G. Minty, I. Pinayev, V. Ptitsyn, T. Rao, T. Roser, B. Sheehy, S. Tepikian, R. Than, D. Trbojevic, J.E. Tuozzolo, G. Wang, V. Yakimenko
BNL, Upton, Long Island, New York, USA
- D.T. Abell, G.I. Bell, D.L. Bruhwiler, C. Nieter, V.H. Ranjbar, B.T. Schwartz
Tech-X, Boulder, Colorado, USA
- A. Hutton, G.A. Krafft, M. Poelker, R.A. Rimmer
JLAB, Newport News, Virginia, USA
- M.A. Kholopov, O.A. Shevchenko, P. Vobly
BINP SB RAS, Novosibirsk, Russia
- P.A. McIntosh, A.E. Wheelhouse
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
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Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, high-intensity hadron-hadron and electron-hadron colliders [1]. In a CEC system, a hadron beam interacts with a cooling electron beam. A perturbation of the electron density caused by ions is amplified and fed back to the ions to reduce the energy spread and the emittance of the ion beam. To demonstrate the feasibility of CEC we propose a proof-of-principle experiment at RHIC using one of JLab’s SRF cryo-modules. In this paper, we describe the experimental setup for CeC installed into one of RHIC's interaction regions. We present results of analytical estimates and results of initial simulations of cooling a gold-ion beam at 40 GeV/u energy via CeC.
[1] Vladimir N. Litvinenko, Yaroslav S. Derbenev, Physical Review Letters 102, 114801
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Slides WEOA3 [3.568 MB]
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