Jefferson Science Associates, LLC

Other

Asml Netherlands B.v.

Los Alamos National Security, LLC

A Jefferson Science Associates, LLC

Stephen V Benson

David R Douglas

George Neil

George Herman Biallas

Thomas Powers

Pavel Evtushenko

Kevin Carl Jordan

John M Madey

Michelle D Shinn

Gwyn P Williams

Dinh Nguyen

Antonello Cutolo

Christopher Tennant

Frank Marhauser

Lucas J P Ament

John F Schultz

Cornelis Apeldoorn

Guy Wilson

Michele D Shinn

Gwyn P Willams

John D Heckman

A method for varying the wavelength of a free electron laser (FEL) by applying an energy dither to the charged particles supplying the FEL. Bunches of charged particle beams are accelerated by cavities that are operated at a harmonic of the bunch repetition rate. The method involves adding one or more secondary radiofrequency accelerator cavities after the primary beam transport and near the wiggler to apply a fluctuation between individual bunches with a pseudo-random distribution. The secondary radiofrequency accelerator cavities provide fine variations of the beam energy about a nominal operating point. Operating a free electron laser (FEL) with a 1% change in the electron beam energy via the added secondary cavities will result in a 2% wavelength variation of the FEL output.

Method for energy dither of a particle beam

A method for applying an energy dither to a charged particle beam in order to vary the wavelength of the charged particle beam. Bunches of charged particle beams are accelerated by cavities that are operated at a harmonic of the bunch repetition rate. One or more secondary radiofrequency accelerator cavities are added near the wiggler after the primary beam transport to apply a fluctuation between individual bunches with a pseudo-random distribution. The secondary radiofrequency accelerator cavities provide fine variations of the beam energy about a nominal operating point. Operating a free electron laser (FEL) with a 1% change in the electron beam energy via the secondary cavity will result in a 2% wavelength variation of the FEL output.

A method for the suppression of upstream-directed field emission in RF accelerators. The method is not restricted to a certain number of cavity cells, but requires similar operating field levels in all cavities to efficiently annihilate the once accumulated energy. Such a field balance is desirable to minimize dynamic RF losses, but not necessarily achievable in reality depending on individual cavity performance, such as early Q-drop or quench field. The method enables a significant energy reduction for upstream-directed electrons within a relatively short distance. As a result of the suppression of upstream-directed field emission, electrons will impact surfaces at rather low energies leading to reduction of dark current and less issues with heating and damage of accelerator components as well as radiation levels including neutron generation and thus radio-activation.

Linear accelerator accelerating module to suppress back-acceleration of field-emitted particles

A method and apparatus for minimizing the degradation of power in a free electron laser (FEL) generating terahertz (THz) radiation. The method includes inserting an absorber ring in the FEL beam path for absorbing any irregular THz radiation and thus minimizes the degradation of downstream optics and the resulting degradation of the FEL output power. The absorber ring includes an upstream side, a downstream side, and a plurality of wedges spaced radially around the absorber ring. The wedges form a scallop-like feature on the innermost edges of the absorber ring that acts as an apodizer, stopping diffractive focusing of the THz radiation that is not intercepted by the absorber. Spacing between the scallop-like features and the shape of the features approximates the Bartlett apodization function. The absorber ring provides a smooth intensity distribution, rather than one that is peaked on-center, thereby eliminating minor distortion downstream of the absorber.

Absorber for terahertz radiation management

A method of bunch length compression method for a free electron laser (FEL) that avoids parasitic compressions by 1) applying acceleration on the falling portion of the RF waveform, 2) compressing using a positive momentum compaction (R&#x3e;0), and 3) compensating for aberration by using nonlinear magnets in the compressor beam line.

Bunch length compression method for free electron lasers to avoid parasitic compressions

The introduction of a magnetic electron beam orbit chicane between the wiggler and the downstream initial bending dipole in an energy recovering Linac alleviates the effects of radiation propagated from the downstream bending dipole that tend to distort the proximate downstream mirror of the optical cavity resonator.

Magnetic chicane for terahertz management

A method of energy recovery for RF-base linear charged particle accelerators that allows energy recovery without large relative momentum spread of the particle beam involving first accelerating a waveform particle beam having a crest and a centroid with an injection energy Ewith the centroid of the particle beam at a phase offset ffrom the crest of the accelerating waveform to an energy Eand then recovering the beam energy centroid a phase f+Df relative to the crest of the waveform particle beam such that()(1+cos(f))&#x3e;/2wherein dE=the full energy spread, dE/2=the full energy half spread and Df=the wave form phase distance.

Use of incomplete energy recovery for the energy compression of large energy spread charged particle beams

The performance of free electron lasers can be greatly enhanced by including a non-linear optical element within the resonator for the oscillator. A system is described to enhance the peak or average power output of the FEL oscillator, or to modify the time structure of the oscillator output through the use of a non-linear element which modulates or diverts a portion of the optical wave circulating in the resonator.

Non-linear intractivity optical devices for free electron lasers

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Yorktown, VA, United States of America

Stephen V Benson