Free Electron Lasers with Variable Parameter Wigglers

Kroll, N.; Morton, P.; Rosenbluth, M. N.

doi:10.21236/ada084323

Cited by 13 publications

(12 citation statements)

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“…This degradation of beam quality weakens the amplification in the downstream undulator section. Therefore, to compensate the degradation and to increase the power growth efficiency, a tapering33 to the UMs after the first 5 UMs is introduced, preserving the resonance condition. Figure 4b reveals the tapering applied along the UMs.…”

Section: Resultsmentioning

confidence: 99%

Temporally-coherent terawatt attosecond XFEL synchronized with a few cycle laser

Kumar

Parc

Landsman

et al. 2016

Sci Rep

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Attosecond metrology using laser-based high-order harmonics has been significantly advanced and applied to various studies of electron dynamics in atoms, molecules and solids. Laser-based high-order harmonics have a limitation of low power and photon energies. There is, however, a great demand for even higher power and photon energy. Here, we propose a scheme for a terawatt attosecond (TW-as) X-ray pulse in X-ray free-electron laser controlled by a few cycle IR pulse, where one dominant current spike in an electron bunch is used repeatedly to amplify a seeded radiation to a terawatt level. This scheme is relatively simple, compact, straightforward, and also produces a temporally and spectrally clean pulse. The viability of this scheme is demonstrated in simulations using Pohang accelerator laboratory (PAL)-XFEL beam parameters.

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Section: Resultsmentioning

confidence: 99%

Temporally-coherent terawatt attosecond XFEL synchronized with a few cycle laser

Kumar

Parc

Landsman

et al. 2016

Sci Rep

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“…Several such designs have been explored theoretically and experimentally for varied purposes. The tapered undulator [3] decreases the undulator wavelength , or the undulator "eld strength, along the undulator length in order to maintain resonance with electrons that lose energy to the laser light. The tapered undulator increases gain and e$ciency in strong optical "elds and extends the usual saturation limit to stronger optical "elds.…”

Section: Introductionmentioning

confidence: 99%

The free electron laser with inverse taper

Colson

McGinnis

2000

Nuclear Instruments and Methods in Physics Research Section A:

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“…The theoretical description of the interaction has been given by a number of authors [2,10]. Approximate analytical expressions derived in Ref.…”

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confidence: 99%

“…Subsequently, 1D and 3D simulation programs were written solving the self-consistent system of Lorentz equations for the electrons and the wave equations for the input laser field as discussed in Ref. [10]. The 1D program has been used to determine the self-consistent wiggler period length and its taper for given values of electron beam energy and laser power and to calculate the bucket acceptance and bucket leakage for a single-or multimodule accelerator.…”

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Observation of Energy Gain at the BNL Inverse Free-Electron-Laser Accelerator

et al. 1996

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A 40 MeV electron beam, using the inverse free-electron-laser interaction, has been accelerated by DE͞E 2.5% over a distance of 0.47 m. The electrons interact with a 1 -2 GW CO 2 laser beam bounded by a 2.8 mm i.d. sapphire circular waveguide in the presence of a tapered wiggler with B max ഠ 1 T, and a period 2.89 # l w # 3.14 cm. The experimental results of DE͞E as a function of electron energy E, peak magnetic field B w , and laser power W l compare well with analytical and 1D numerical simulations and permit scaling to higher laser power and electron energy.[S0031-9007(96)01273-2] PACS numbers: 41.75.Lx, 41.60.Cr, 41.75.Ht, 52.75.Ms Since the inception of practicable lasers, laser-driven acceleration concepts have been intensively studied. The interest resides in the use of the very large electric fields achievable by focusing the laser to very small spots. These fields are well in excess of the accelerating gradients currently obtained in rf cavities. The study of the inverse free-electron laser (IFEL) as a potential mode of electron acceleration has been pursued at Brookhaven National Laboratory (BNL) for a number of years [1][2][3][4]. Although the concept has been studied theoretically in detail, the first experimental verification of the concept (l 1.65 mm) was performed in 1992 [5]. In this Letter further experimental evidence of the IFEL interaction (l 10.6 mm) is presented. The experiment used a 50 MeV electron beam, a 1-5 GW CO 2 laser beam provided by the BNL's Accelerator Test Facility (ATF) and a uniquely designed period length tapered wiggler.This wiggler is a fast excitation electromagnet with stackable, geometrically and magnetically alternating substacks of vanadium permendur (VaP) ferromagnetic laminations, periodically interspersed with conductive (Cu), nonmagnetic laminations, which act as eddy current induced field reflectors [6,7]. Four current conducting rods, parallel to the wiggler axis, are connected at the ends of the assembly, constituting the excitation loop that drives the wiggler. The overall wiggler stack is easily assembled, is compressed by simple tie rods, and readily permits wiggler period length (l w ) variation. Configured as a constant period wiggler, l w 3.75 cm and B max 1 T, the system has shown [7] an rms pole-to-pole field variation of approximately 0.2%.The CO 2 laser beam is brought into the IFEL interaction region by a low loss dielectric (sapphire) circular waveguide. Two different guide configurations were tested, first a 1 4 l dielectric coating (germanium) deposited on the two lateral walls of a rectangular cross-section metallic waveguide [8] and then a sapphire (Al 2 O 3 ) circular waveguide, which showed very good transmission properties [9] of a high power CO 2 laser beam. Extensive studies were carried out to establish optimum coupling into the guide and to measure the transmission loss of long (1.0 m) extruded single crystal sapphire guides. Also, because of the overmoded guide configuration (i.d. 2.8 mm), attempts were made to determine the transverse...

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Free Electron Lasers with Variable Parameter Wigglers

Cited by 13 publications

References 0 publications

Temporally-coherent terawatt attosecond XFEL synchronized with a few cycle laser

Temporally-coherent terawatt attosecond XFEL synchronized with a few cycle laser

The free electron laser with inverse taper

Observation of Energy Gain at the BNL Inverse Free-Electron-Laser Accelerator

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