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Sample records for advanced free-electron laser

  1. Los Alamos Advanced Free-Electron Laser

    SciTech Connect

    Chan, K.C.D.; Kraus, R.H.; Ledford, J.; Meier, K.L.; Meyer, R.E.; Nguyen, D.; Sheffield, R.L.; Sigler, F.L.; Young, L.M.; Wang, T.S.; Wilson, W.L.; Wood, R.L.

    1991-01-01

    At Los Alamos, we are building a free-electron laser (FEL) for industrial, medical, and research applications. This FEL, which will incorporate many of the new technologies developed over the last decade, will be compact in size, robust, and user-friendly. Electrons produced by a photocathode will be accelerated to 20 MeV by a high-brightness accelerator and transported using permanent-magnet quadrupoles and dipoles. They will form an electron beam with an excellent instantaneous beam quality of 10 {pi} mm mrad in transverse emittance and 0.3% in energy spread at a peak current up to 300 A. Including operation at higher harmonics, the laser wavelength extends form 3.7 {mu}m to 0.4 {mu}m. In this paper, we will describe the project and the programs to date. 10 refs., 10 figs., 1 tab.

  2. Inverse free electron laser accelerator for advanced light sources

    NASA Astrophysics Data System (ADS)

    Duris, J. P.; Musumeci, P.; Li, R. K.

    2012-06-01

    We discuss the inverse free electron laser (IFEL) scheme as a compact high gradient accelerator solution for driving advanced light sources such as a soft x-ray free electron laser amplifier or an inverse Compton scattering based gamma-ray source. In particular, we present a series of new developments aimed at improving the design of future IFEL accelerators. These include a new procedure to optimize the choice of the undulator tapering, a new concept for prebunching which greatly improves the fraction of trapped particles and the final energy spread, and a self-consistent study of beam loading effects which leads to an energy-efficient high laser-to-beam power conversion.

  3. Recent progress of the Los Alamos advanced free electron laser

    SciTech Connect

    Nguyen, D.C.; Austin, R.H.; Chan, K.C.D.; Feldman, D.W.; Goldstein, J.C.; Gierman, S.M.; Kinross-Wright, J.M.; Kong, S.H.; Plato, J.G.; Russell, S.J.

    1994-05-01

    Many industrial and research applications can benefit from the availability of a compact, user-friendly, broadly tunable and high average power free electron laser (FEL). Over the past four years, the Los Alamos Advanced FEL has been built with these design goals. The key to a compact FEL is the integration of advanced beam technologies such as a high-brightness photoinjector, a high-gradient compact linac, and permanent magnet beamline components. These technologies enable the authors to shrink the FEL size yet maintain its high average power capability. The Advanced FEL has been in operation in the near ir (4-6 {mu}m) since early 1993. Recent results of the Advanced FEL lasing at saturation and upgrades to improve its average power are presented.

  4. Advances in tunable powerful lasers: The advanced free-electron laser

    SciTech Connect

    Singer, S.; Sheffield, R.

    1993-12-31

    In the past several decades, remarkable progress in laser science and technology has made it possible to obtain laser light from the ultra-violet to the far infra-red from a variety of laser types, and at power levels from milliwatts to kilowatts (and, some day, megawatts). However, the availability of tunable lasers at ``high`` power (above a few tens of watts) is more limited. Figure 1, an assessment of the availability of tunable lasers, shows the covered range to be about 400 to 2000 nanometers. A variety of dye lasers cover the visible and near infra red, each one of which is tunable over approximately a 10% range. In the same region, the TI:saphire laser is adjustable over a 20 to 25% range. And finally, optical parametric oscillators can cover the range from about 400 nanometers out to about 2000 nm (even farther at reduced energy output). The typical output energy per pulse may vary from a few to one hundred millijoules, and since repetition rates of 10 to 100 Hertz are generally attainable, average output powers of tens of watts are possible. In recent years, a new approach to powerful tunable lasers -- the Free-Electron Laser (FEL) -- has emerged. In this paper we will discuss advances in FEL technology which not only enable tunability at high average power over a very broad range of wavelengths, but also make this device more usable. At present, that range is about one micron to the far infra red; with extensions of existing technology, it should be extendable to the vacuum ultra violet region.

  5. Initial performance of Los Alamos Advanced Free Electron Laser

    SciTech Connect

    Nguyen, D.C.; Baca, D.M.; Chan, K.C.D.; Cheairs, R.B.; Fortgang, C.M.; Gierman, S.M.; Johnson, W.J.D.; Holcomb, D.E.; Kinross-Wright, J.; McCann, S.W.; Meier, K.L.; Plato, J.G.; Sheffield, R.L.; Sherwood, B.A.; Sigler, F.E.; Timmer, C.A.; Warren, R.W.; Weber, M.E.; Wilson, W.L.

    1992-09-01

    We report recent results on the high-brightness electron linac and initial performance of the Advanced FEL at Los Alamos. The design and construction of the Advanced FEL beamline are based upon integration of advanced technologies such as high-brightness photoinjector, high-gradient compact linac, and permanent-magnet beamline components. With the use of microwiggler, both permanent magnet and pulsed electromagnet, and compact optical resonator, the Advanced FEL will be the first of its kind small enough to be mounted on an optical table and yet capable of providing highpower optical output spanning the near-ir and visible regions. A schematic of the Advanced FEL is shown in. The source of high-current electron pulses is a laser-gated photoelectron injector which forms-an integral part of a high-gradient 1.2-m long rf linear accelerator. The latter is capable of accelerating electrons up to 20 MeV with room temperature operation and 25 MeV at 77K. The electrons are produced in 10-ps pulses with peak currents as high as 300 A. These electron pulses are transported in a brightness-preserving beamline consisting of permanent magnet dipoles and quadrupoles. The beamline has three 30{degrees} bends. The first bend allows for the photocathode drive laser input; the second allows for the FEL output and the third turns the electron beam into the floor for safety reasons. Additional information on the design physics of the Advanced FEL can be found elsewhere.

  6. Initial performance of Los Alamos Advanced Free Electron Laser

    SciTech Connect

    Nguyen, D.C.; Baca, D.M.; Chan, K.C.D.; Cheairs, R.B.; Fortgang, C.M.; Gierman, S.M.; Johnson, W.J.D.; Holcomb, D.E.; Kinross-Wright, J.; McCann, S.W.; Meier, K.L.; Plato, J.G.; Sheffield, R.L.; Sherwood, B.A.; Sigler, F.E.; Timmer, C.A.; Warren, R.W.; Weber, M.E.; Wilson, W.L.

    1992-01-01

    We report recent results on the high-brightness electron linac and initial performance of the Advanced FEL at Los Alamos. The design and construction of the Advanced FEL beamline are based upon integration of advanced technologies such as high-brightness photoinjector, high-gradient compact linac, and permanent-magnet beamline components. With the use of microwiggler, both permanent magnet and pulsed electromagnet, and compact optical resonator, the Advanced FEL will be the first of its kind small enough to be mounted on an optical table and yet capable of providing highpower optical output spanning the near-ir and visible regions. A schematic of the Advanced FEL is shown in. The source of high-current electron pulses is a laser-gated photoelectron injector which forms-an integral part of a high-gradient 1.2-m long rf linear accelerator. The latter is capable of accelerating electrons up to 20 MeV with room temperature operation and 25 MeV at 77K. The electrons are produced in 10-ps pulses with peak currents as high as 300 A. These electron pulses are transported in a brightness-preserving beamline consisting of permanent magnet dipoles and quadrupoles. The beamline has three 30{degrees} bends. The first bend allows for the photocathode drive laser input; the second allows for the FEL output and the third turns the electron beam into the floor for safety reasons. Additional information on the design physics of the Advanced FEL can be found elsewhere.

  7. Catalac free electron laser

    DOEpatents

    Brau, C.A.; Swenson, D.A.; Boyd, T.J. Jr.

    1979-12-12

    A catalac free electron laser using a rf linac (catalac) which acts as a catalyst to accelerate an electron beam in an initial pass through the catalac and decelerate the electron beam during a second pass through the catalac is described. During the second pass through the catalac, energy is extracted from the electron beam and transformed to energy of the accelerating fields of the catalac to increase efficiency of the device. Various embodiments disclose the use of post linacs to add electron beam energy extracted by the wiggler and the use of supplementary catalacs to extract energy at various energy peaks produced by the free electron laser wiggler to further enhance efficiency of the catalac free electron laser. The catalac free electron laser can be used in conjunction with a simple resonator, a ring resonator, or as an amplifier in conjunction with a master oscillator laser.

  8. Catalac free electron laser

    DOEpatents

    Brau, Charles A.; Swenson, Donald A.; Boyd, Jr., Thomas J.

    1982-01-01

    A catalac free electron laser using a rf linac (catalac) which acts as a catalyst to accelerate an electron beam in an initial pass through the catalac and decelerate the electron beam during a second pass through the catalac. During the second pass through the catalac, energy is extracted from the electron beam and transformed to energy of the accelerating fields of the catalac to increase efficiency of the device. Various embodiments disclose the use of post linacs to add electron beam energy extracted by the wiggler and the use of supplementary catalacs to extract energy at various energy peaks produced by the free electron laser wiggler to further enhance efficiency of the catalac free electron laser. The catalac free electron laser can be used in conjunction with a simple resonator, a ring resonator or as an amplifier in conjunction with a master oscillator laser.

  9. Initial performance of Los Alamos Advanced Free Electron Laser

    SciTech Connect

    Nguyen, D.C.; Austin, R.H.; Chan, K.C.D.

    1993-09-01

    The Los Alamos compact Advanced FEL has lased at 4.7 and 5.2 {mu}m with a 1-cm period wiggler and a high-brightness electron beam at 16.8 and 15.8 MeV, respectively. The measured electron beam normalized emittance is 1.7 {pi}{center_dot}mm{center_dot}mrad at a peak current of 100 A, corresponding to a beam brightness greater than 2 {times} 10{sup 12} A/m{sup 2}rad{sup 2}. Initial results indicate that the AFEL small signal gain is {approximately}8% at 0.3 nC (30 A peak). The maximum output energy is 7 mJ over a 2-{mu}s macropulse. The AFEL performance can be significantly enhanced by improvements in the rf and drive laser stability.

  10. Free-Electron Lasers.

    ERIC Educational Resources Information Center

    Brau, Charles A.

    1988-01-01

    Describes the use of free-electron lasers as a source of coherent radiation over a broad range of wavelengths from the far-infrared to the far-ultraviolet regions of the spectrum. Discusses some applications of these lasers, including medicine and strategic defense. (TW)

  11. Free-Electron Lasers.

    ERIC Educational Resources Information Center

    Brau, Charles A.

    1988-01-01

    Describes the use of free-electron lasers as a source of coherent radiation over a broad range of wavelengths from the far-infrared to the far-ultraviolet regions of the spectrum. Discusses some applications of these lasers, including medicine and strategic defense. (TW)

  12. FREE-ELECTRON LASERS

    SciTech Connect

    Sessler, A.M.; Vaughan, D.

    1986-04-01

    We can now produce intense, coherent light at wavelengths where no conventional lasers exist. The recent successes of devices known as free-electron lasers mark a striking confluence of two conceptual developments that themselves are only a few decades old. The first of these, the laser, is a product of the fifties and sixties whose essential characteristics have made it a staple resource in almost every field of science and technology. In a practical sense, what defines a laser is its emission of monochromatic, coherent light (that is, light of a single wavelength, with its waves locked in step) at a wavelength in the infrared, visible, or ultraviolet region of the electromagnetic spectrum. A second kind of light, called synchrotron radiation, is a by-product of the age of particle accelerators and was first observed in the laboratory in 1947. As the energies of accelerators grew in the 1960s and 70s, intense, incoherent beams of ultraviolet radiation and x--rays became available at machines built for high-energy physics research. Today, several facilities operate solely as sources of synchrotron light. Unlike the well-collimated monochromatic light emitted by lasers, however, this incoherent radiation is like a sweeping searchlight--more accurately, like the headlight of a train on a circular track--whose wavelengths encompass a wide spectral band. Now, in several laboratories around the world, researchers have exploited the physics of these two light sources and have combined the virtues of both in a single contrivance, the free-electron laser, or FEL (1). The emitted light is laserlike in its narrow, sharply peaked spectral distribution and in its phase coherence, yet it can be of a wavelength unavailable with ordinary lasers. Furthermore, like synchrotron radiation, but unlike the output of most conventional lasers, the radiation emitted by free-electron lasers can be tuned, that is, its wavelength can be easily varied across a wide range. The promise of this

  13. Free electron laser

    DOEpatents

    Villa, Francesco

    1990-01-01

    A high gain, single-pass free electron laser formed of a high brilliance electron injector source, a linear accelerator which imparts high energy to the electron beam, and an undulator capable of extremely high magnetic fields, yet with a very short period. The electron injector source is the first stage (gap) of the linear accelerator or a radial line transformer driven by fast circular switch. The linear accelerator is formed of a plurality of accelerating gaps arranged in series. These gaps are energized in sequence by releasing a single pulse of energy which propagates simultaneously along a plurality of transmission lines, each of which feeds the gaps. The transmission lines are graduated in length so that pulse power is present at each gap as the accelerated electrons pass therethrough. The transmission lines for each gap are open circuited at their ends. The undualtor has a structure similar to the accelerator, except that the transmission lines for each gap are substantially short circuited at their ends, thus converting the electric field into magnetic field. A small amount of resistance is retained in order to generate a small electric field for replenishing the electron bunch with the energy lost as it traverses through the undulator structure.

  14. FREE ELECTRON LASERS

    SciTech Connect

    Colson, W.B.; Sessler, A.M.

    1985-01-01

    The free electron laser (FEL) uses a high quality relativistic beam of electrons passing through a periodic magnetic field to amplify a copropagating optical wave (1-4). In an oscillator configuration, the light is stored between the mirrors of an open optical resonator as shown in Figure 1. In an amplifier configuration, the optical wave and an intense electron beam pass through the undulator field to achieve high gain. In either case, the electrons must overlap the optical mode for good coupling. Typically, the peak electron beam current varies from several amperes to many hundreds of amperes and the electron energy ranges from a few MeV to a few GeV. The electrons are the power source in an FEL, and provide from a megawatt to more than a gigawatt flowing through the resonator or amplifier system. The undulator resonantly couples the electrons to the transverse electrical field of the optical wave in vacuum. The basic mechanism of the coherent energy exchange is the bunching of the electrons at optical wavelengths. Since the power source is large, even small coupling can result in a powerful laser. Energy extraction of 5% of the electron beam energy has already been demonstrated. The electron beam quality is crucial in maintaining the coupling over a significant interaction distance and of central importance to all FEL systems is the magnetic undulator. The peak undulator field strength is usually several kG and can be constructed from coil windings or permanent magnets. In the top part of Figure 2, the Halbach undulator design is shown for one period. The field can be achieved, to a good approximation, using permanent magnets made out of rare earth compounds; a technique developed by K. Halbach (5), and now employed in most undulators. The undulator wavelength is in the range of a few centimeters and the undulator length extends for a few meters, so that there are several hundred periods for the interaction (6-8). The polarization of the undulator can be either

  15. Circular free-electron laser

    DOEpatents

    Brau, Charles A.; Kurnit, Norman A.; Cooper, Richard K.

    1984-01-01

    A high efficiency, free electron laser utilizing a circular relativistic electron beam accelerator and a circular whispering mode optical waveguide for guiding optical energy in a circular path in the circular relativistic electron beam accelerator such that the circular relativistic electron beam and the optical energy are spatially contiguous in a resonant condition for free electron laser operation. Both a betatron and synchrotron are disclosed for use in the present invention. A free electron laser wiggler is disposed around the circular relativistic electron beam accelerator for generating a periodic magnetic field to transform energy from the circular relativistic electron beam to optical energy.

  16. Rf feedback free electron laser

    DOEpatents

    Brau, C.A.; Swenson, D.A.; Boyd, T.J. Jr.

    1979-11-02

    A free electron laser system and electron beam system for a free electron laser are provided which use rf feedback to enhance efficiency. Rf energy is extracted from an electron beam by decelerating cavities and returned to accelerating cavities using rf returns such as rf waveguides, rf feedthroughs, etc. This rf energy is added to rf klystron energy to lower the required input energy and thereby enhance energy efficiency of the system.

  17. Rf Feedback free electron laser

    DOEpatents

    Brau, Charles A.; Swenson, Donald A.; Boyd, Jr., Thomas J.

    1981-01-01

    A free electron laser system and electron beam system for a free electron laser which use rf feedback to enhance efficiency. Rf energy is extracted from an electron beam by decelerating cavities and returned to accelerating cavities using rf returns such as rf waveguides, rf feedthroughs, etc. This rf energy is added to rf klystron energy to lower the required input energy and thereby enhance energy efficiency of the system.

  18. Research on Free Electron Lasers

    DTIC Science & Technology

    1989-01-01

    Communication 52, 409 (1985). [15] W. B. Colson, Free Electron Generators of Coherent Radiation, SPIE 453, 289, eds. Brau, Jacobs , Scully (1984). [16...quantum electrodynamics [39,401. Later, classical methods were shown to be accurate and complete (41-46]. The quasi- Bioch equations have enhanced the laser...of Phys. 7, 84 (1959). [7] Proceedings of the First Free Electron Laser Conference, Telluride, CO, eds. S. F. Jacobs , M. Sargent, III, and M. 0

  19. Hybrid free electron laser devices

    SciTech Connect

    Asgekar, Vivek; Dattoli, G.

    2007-03-15

    We consider hybrid free electron laser devices consisting of Cerenkov and undulator sections. We will show that they can in principle be used as segmented devices and also show the possibility of exploiting Cerenkov devices for the generation of nonlinear harmonic coherent power. We discuss both oscillator and amplifier schemes.

  20. A 1-kW power demonstration from the advanced free electron laser

    SciTech Connect

    Sheffield, R.L.; Conner, C.A.; Fortgang, C.M.

    1997-08-01

    This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The main objective of this project was to engineer and procure an electron beamline compatible with the operation of a 1-kW free-electron laser (FEL). Another major task is the physics design of the electron beam line from the end of the wiggler to the electron beam dump. This task is especially difficult because electron beam is expected to have 20 kW of average power and to simultaneously have a 25% energy spread. The project goals were accomplished. The high-power electron design was completed. All of the hardware necessary for high-power operation was designed and procured.

  1. The UK free electron laser

    NASA Astrophysics Data System (ADS)

    Laing, E. W.

    1985-12-01

    The basic operating principles of a free electron laser (FEL) are reviewed. A description of a British research program to develop a pulsed relativistic electron beam and laser cavity for infrared and optical operation, the UK FEL program, is given. The tunable energy of the UK FEL is in the range 50-125 MeV, and the current is greater than or equal to 200 mA. The FEL Wiggler field consists of a periodic structure of permanent magnets made up of four sections each. The main goals of the UK FEL program are to study the spontaneous emission of the electron beam, as well as the amplification characteristics of the CO2 laser beam. Some of the prospective applications of infrared FELs include: single or multiphoton excitation; molecular dissociation; excitation of charge carriers over the infrared range; and optical bistable switching.

  2. High Power Free Electron Lasers

    SciTech Connect

    George Neil

    2004-04-12

    FEL Oscillators have been around since 1977 providing not only a test bed for the physics of Free Electron Lasers and electron/photon interactions but as a workhorse of scientific research. The characteristics that have driven the development of these sources are the desire for high peak and average power, high pulse energies, wavelength tunability, timing flexibility, and wavelengths that are unavailable from more conventional laser sources. User programs have been performed using such sources encompassing medicine, biology, solid state research, atomic and molecular physics, effects of non-linear fields, surface science, polymer science, pulsed laser vapor deposition, to name just a few. Recently the incorporation of energy recovery systems has permitted extension of the average power capabilities to the kW level and beyond. Development of substantially higher power systems with applications in defense and security is believed feasible with modest R&D efforts applied to a few technology areas. This paper will discuss at a summary level the physics of such devices, survey existing and planned facilities, and touch on the applications that have driven the development of these popular light sources.

  3. Progress toward the Wisconsin Free Electron Laser

    SciTech Connect

    Bisognano, Joseph; Eisert, D; Fisher, M V; Green, M A; Jacobs, K; Kleman, K J; Kulpin, J; Rogers, G C; Lawler, J E; Yavuz, D; Legg, R

    2011-03-01

    The University of Wisconsin-Madison/Synchrotron Radiation Center is advancing its design for a seeded VUV/soft X-ray Free Electron Laser facility called WiFEL. To support this vision of an ultimate light source, we are pursuing a program of strategic R&D addressing several crucial elements. This includes development of a high repetition rate, VHF superconducting RF electron gun, R&D on photocathode materials by ARPES studies, and evaluation of FEL facility architectures (e.g., recirculation, compressor scenarios, CSR dechirping, undulator technologies) with the specific goal of cost containment. Studies of high harmonic generation for laser seeding are also planned.

  4. Anomalous free electron laser interaction

    NASA Astrophysics Data System (ADS)

    Einat, M.; Jerby, E.; Kesar, A.

    2002-05-01

    Free electron lasers (FELs) are considered, typically, as fast wave devices. The normal FEL interaction satisfies the tuning condition ω≅( kz+ kW) Vz , where ω and kz are the em-wave angular frequency and longitudinal wave number, respectively, Vz is the electron axial speed, and kW is the wiggler periodicity. This paper presents an anomalous FEL interaction, which may occur in slow-wave FELs (i.e. loaded by dielectric or periodic structures). The anomalous FEL effect presented here satisfies the tuning condition ω≅( kz- kW) Vz , and it resembles the anomalous effect in slow-wave cyclotron resonance masers. A necessary condition for the anomalous interaction is ω/ kz< Vz (i.e., the em-wave phase velocity should be slower than the electron beam). The paper presents a preliminary experimental result demonstrating the anomalous FEL effect in a stripline dielectric-loaded FEL experiment. A linear Pierce equation is applied to describe both the anomalous and normal FELs in the same framework. The paper is concluded with a conceptual discussion.

  5. Free-electron lasers. Status and applications.

    PubMed

    O'Shea, P G; Freund, H P

    2001-06-08

    A free-electron laser consists of an electron beam propagating through a periodic magnetic field. Today such lasers are used for research in materials science, chemical technology, biophysical science, medical applications, surface studies, and solid-state physics. Free-electron lasers with higher average power and shorter wavelengths are under development. Future applications range from industrial processing of materials to light sources for soft and hard x-rays.

  6. Free electron laser designs for laser amplification

    DOEpatents

    Prosnitz, Donald; Szoke, Abraham

    1985-01-01

    Method for laser beam amplification by means of free electron laser techniques. With wiggler magnetic field strength B.sub.w and wavelength .lambda..sub.w =2.pi./k.sub.w regarded as variable parameters, the method(s) impose conditions such as substantial constancy of B.sub.w /k.sub.w or k.sub.w or B.sub.w and k.sub.w (alternating), coupled with a choice of either constant resonant phase angle or programmed phase space "bucket" area.

  7. Airborne Tactical Free-Electron Laser

    SciTech Connect

    Whitney, Roy; Neil, George

    2007-02-01

    The goal of 100 kilowatts (kW) of directed energy from an airborne tactical platform has proved challenging due to the size and weight of most of the options that have been considered. However, recent advances in Free-Electron Lasers appear to offer a solution along with significant tactical advantages: a nearly unlimited magazine, time structures for periods from milliseconds to hours, radar like functionality, and the choice of the wavelength of light that best meets mission requirements. For an Airborne Tactical Free-Electron Laser (ATFEL) on a platforms such as a Lockheed C-130J-30 and airships, the two most challenging requirements, weight and size, can be met by generating the light at a higher harmonic, aggressively managing magnet weights, managing cryogenic heat loads using recent SRF R&D results, and using FEL super compact design concepts that greatly reduce the number of components. The initial R&D roadmap for achieving an ATFEL is provided in this paper. Performing this R&D is expected to further reduce the weight, size and power requirements for the FELs the Navy is currently developing for shipboard applications, as well as providing performance enhancements for the strategic airborne MW class FELs. The 100 kW ATFEL with its tactical advantages may prove sufficiently attractive for early advancement in the queue of deployed FELs.

  8. Combination free electron and gaseous laser

    DOEpatents

    Brau, Charles A.; Rockwood, Stephen D.; Stein, William E.

    1980-01-01

    A multiple laser having one or more gaseous laser stages and one or more free electron stages. Each of the free electron laser stages is sequentially pumped by a microwave linear accelerator. Subsequently, the electron beam is directed through a gaseous laser, in the preferred embodiment, and in an alternative embodiment, through a microwave accelerator to lower the energy level of the electron beam to pump one or more gaseous lasers. The combination laser provides high pulse repetition frequencies, on the order of 1 kHz or greater, high power capability, high efficiency, and tunability in the synchronous production of multiple beams of coherent optical radiation.

  9. Biological applications of ultraviolet free-electron lasers

    SciTech Connect

    Sutherland, J.C.

    1997-10-01

    This review examines the possibilities for biological research using the three ultraviolet free-electron lasers that are nearing operational status in the US. The projected operating characteristics of major interest in biological research of the free-electron lasers at Brookhaven National Laboratory, the Thomas Jefferson National Accelerator Facility, and Duke University are presented. Experimental applications in the areas of far- and vacuum ultraviolet photophysics and photochemistry, structural biology, environmental photobiology, and medical research are discussed and the prospects for advances in these areas, based upon the characteristics of the new ultraviolet free-electron lasers, are evaluated.

  10. Two-Stage Free Electron Laser Research.

    DTIC Science & Technology

    1984-10-24

    Ctmetenar an reverse ode It ne*eey aud identify fo black nmber) Free electron laser, two-stage free electron laser, quasioptical cavity, helical ...of very high intensity (_10 W/cm ). A quasioptical cavity concept has been developed to produce such a field. A helical wiggler is needed to excite...the TE waveguide mode in this cavity. Work is described on the development of a pfmanent magnet helical wiggler for this system. Off-axis electron

  11. Self-amplified spontaneous emission saturation at the Advanced Photon Source free-electron laser (abstract) (invited)

    NASA Astrophysics Data System (ADS)

    Moog, E. R.; Milton, S. V.; Arnold, N. D.; Benson, C.; Berg, W.; Biedron, S. G.; Borland, M.; Chae, Y.-C.; Dejus, R. J.; Den Hartog, P. K.; Deriy, B.; Erdmann, M.; Gluskin, E.; Huang, Z.; Kim, K.-J.; Lewellen, J. W.; Li, Y.; Lumpkin, A. H.; Makarov, O.; Nassiri, A.; Sajaev, V.; Soliday, R.; Tieman, B. J.; Trakhtenberg, E. M.; Travish, G.; Vasserman, I. B.; Vinokurov, N. A.; Wiemerslage, G.; Yang, B. X.

    2002-03-01

    Today, many bright photon beams in the ultraviolet and x-ray wavelength range are produced by insertion devices installed in specially designed third-generation storage rings. There is the possibility of producing photon beams that are orders of magnitude brighter than presently achieved at synchrotron sources, by using self-amplified spontaneous emission (SASE). At the Advanced Photon Source (APS), the low-energy undulator test line (LEUTL) free-electron laser (FEL) project was built to explore the SASE process in the visible through vacuum ultraviolet wavelength range. While the understanding gained in these experiments will guide future work to extend SASE FELs to shorter wavelengths, the APS FEL itself will become a continuously tunable, bright light source. Measurements of the SASE process to saturation have been made at 530 and 385 nm. A number of quantities were measured to confirm our understanding of the SASE process and to verify that saturation was reached. The intensity of the FEL light was measured versus distance along the FEL, and was found to flatten out at saturation. The statistical variation of the light intensity was found to be wide in the exponential gain region where the intensity is expected to be noisy, and narrower once saturation was reached. Absolute power measurements compare well with GINGER simulations. The FEL light spectrum at different distances along the undulator line was measured with a high-resolution spectrometer, and the many sharp spectral spikes at the beginning of the SASE process coalesce into a single peak at saturation. The energy spread in the electron beam widens markedly after saturation due to the number of electrons that transfer a significant amount of energy to the photon beam. Coherent transition radiation measurements of the electron beam as it strikes a foil provide additional confirmation of the microbunching of the electron beam. The quantities measured confirm that saturation was indeed reached. Details are

  12. Development of Advanced Beam Halo Diagnostics at the Jefferson Lab Free-Electron-Laser Facility

    SciTech Connect

    Shukui Zhang, Stephen Benson, Dave Douglas, Frederick Wilson, Hao Zhang, Anatoly Shkvarunets, Ralph Fiorito

    2011-03-01

    High average current and high brightness electron beams are needed for many applications. At the Jefferson Lab FEL facility, the search for dark matter with the FEL laser beam has produced some interesting results, and a second very promising experiment called DarkLight, using the JLab Energy-recovery-linac (ERL) machine has been put forward. Although the required beam current has been achieved on this machine, one key challenge is the management of beam halo. At the University of Md. (UMD) we have demonstrated a high dynamic range halo measurement method using a digital micro-mirror array device (DMD). A similar system has been established at the JLab FEL facility as a joint effort by UMD and JLab to measure the beam halo on the high current ERL machine. Preliminary experiments to characterize the halo were performed on the new UV FEL. In this paper, the limitations of the present system will be analyzed and a discussion of other approaches (such as an optimized coronagraph) for further extending the dynamic range will be presented. We will also discuss the possibility of performing both longitudinal and transverse (3D) halo measurements together on a single system.

  13. Midwest Free Electron Laser Program

    DTIC Science & Technology

    1988-07-31

    PDT ) at the molecular level: a light scattering tissue with intrinisic absorption, the photosensitizer , and a singlet-oxygen sensitive biological target...particular significance, since the various projects are interdependent, being concerned with clinical studies of laser effects in neurosurgery, laser delivery...potato is being investigated with Photofrin II as the photosensitizer . This model system includes the key compcnents of photodynamic tumor therapy

  14. Biomedical Free Electron Laser Studies

    DTIC Science & Technology

    1988-01-01

    consistent with a;(echanism mediated by singlet oxygen. Involvement of peroxide and radicals havŚt been strictly ruled out. Exposures to laser light that...1981) J. Cell Biology 2Q:595-604. Tan, 0. and S. Kennedy (1987) Abstract 21. Lasers in Surg. and Med. 7-73.SI I I ! ! I I I I I I CHART IS~-~OO3 - ~ -F...tryptophan, enzyme activity and production of "daughter products". The latter appear to include N- formyl -kynurenine, kynurenine, tryptamine, and

  15. Isochronous Beamlines for Free Electron Lasers

    SciTech Connect

    Berz, M.

    1990-07-01

    The transport systems required to feed a beam of highly relativistic electrons into a free electron laser have to satisfy very stringent requirements with respect to isochronicity and achromaticity. In addition, the line has to be tunable to match different operating modes of the free electron laser. Various beamlines emphasizing different aspects, such as quality of isochronicity and achromaticity, simplicity of the design, and space configurations are shown and compared. Solutions are presented having time resolution in the range of 2 to less than 0.5 picoseconds for one percent of energy spread.

  16. Free electron laser mode dynamics

    NASA Astrophysics Data System (ADS)

    Kan, Shidong

    The University of Hawai'i at Manoa (UHM) Fox-Smith project opens a door for great research opportunities to the fields of high resolution infrared laser spectroscopy, quantum optics, coherent x-ray production and new and fundamental applications of phase-locked pulse trains and coherent frequency combs. An understanding of FEL mode dynamics is essential for facilitating this multimirror laser cavity design and improving laser performance for applications. Of particular interest is the nonlinear mode competition and mode evolution in the time domain which can give insight understanding of FELs' mode spectrum evolution. In this dissertation, I report the first thorough investigation and analysis of the nonlinear mode competition and mode evolution from the small signal regime through deep saturation using a time domain full particle simulation code based on the fundamental FEL equations of motion. It is found that the passive eigenmode theory of multimirror resonator FEL is not fully applicable in the large signal saturated regime. Extreme mode competition at the midpoint-phase offset versus beamsplitter reflectance indicating enhanced single mode operation is also discovered. In addition, matrix analysis including the proper form of the FEL gain saturation and the phase of the complex gain is also performed. This dissertation, for the first time known to the author, proposes a Michelson configuration which couples every third pulse. The feasibility and performance of the proposed configuration is elaborately investigated. An experimental design for evaluating the extreme mode competition effect discovered during the course of this dissertation research is described, based on the Mark V FEL in the current Michelson and the proposed new Michelson configurations. Finally, I report the construction and calibration of a Fox-Smith beamsplitter using a rotatable birefringent sapphire plate. High assembly precision is achieved. The angular beam wander caused by the rotation

  17. Optical wavelength modulation in free electron lasers

    SciTech Connect

    Mabe, R.M.; Wong, R.K.; Colson, W.B.

    1995-12-31

    An attribute of the free electron laser (FEL) is the continuous tunability of the optical wavelength by modulation of the electron beam energy. The variation of the wavelength and power of the optical beam is studied as a function of FEL operating parameters. These results will be applied to the Stanford SCA FEL and Boeing FEL.

  18. Applications for Energy Recovering Free Electron Lasers

    SciTech Connect

    George Neil

    2007-08-01

    The availability of high-power, high-brilliance sources of tunable photons from energy-recovered Free Electron Lasers is opening up whole new fields of application of accelerators in industry. This talk will review some of the ideas that are already being put into production, and some of the newer ideas that are still under development.

  19. Operation of the high-brightness linac for the advanced free-electron laser initiative at Los Alamos

    SciTech Connect

    Sheffield, R.L.; Austin, R.H.; Chan, K.C.D.; Gierman, S.M.; Kinross-Wright, J.M.; Kong, S.H.; Nguyen, D.C.; Russell, S.J.; Timmer, C.A.

    1993-08-01

    Free-electron lasers and high-energy physics accelerators have increased the demand for very high-brightness beam sources. This paper describes the design of an accelerator which has produced beams of 2.1 {pi} mm-mrad at 1 nC and emittances of 3.7 and 6.5 {pi} mm-mrad for 2 and 3 nC, respectively. The accelerator has been operated between 10 and 18 MeV. The beam emittance growth in the accelerator is minimized by using a photoinjector electron source integrated into the design of the linac, a focusing solenoid to correct the emittance growth caused by space charge, and a special design of the coupling slots between accelerator cavities to minimize quadrupole effects. The FEL has recently operated at 5 microns.

  20. Nonlinear optics with coherent free electron lasers

    NASA Astrophysics Data System (ADS)

    Bencivenga, F.; Capotondi, F.; Mincigrucci, R.; Cucini, R.; Manfredda, M.; Pedersoli, E.; Principi, E.; Simoncig, A.; Masciovecchio, C.

    2016-12-01

    We interpreted the recent construction of free electron laser (FELs) facilities worldwide as an unprecedented opportunity to bring concepts and methods from the scientific community working with optical lasers into the domain of x-ray science. This motivated our efforts towards the realization of FEL-based wave-mixing applications. In this article we present new extreme ultraviolet transient grating (X-TG) data from vitreous SiO2, collected using two crossed FEL pulses (photon frequency 38 eV) to generate the X-TG and a phase matched optical probing pulse (photon frequency 3.1 eV). This experiment extends our previous investigation, which was carried out on a nominally identical sample using a different FEL photon frequency (45 eV) to excite the X-TG. The present data are featured by a peak intensity of the X-TG signal substantially larger than that previously reported and by slower modulations of the X-TG signal at positive delays. These differences could be ascribed to the different FEL photon energy used in the two experiments or to differences in the sample properties. A systematic X-TG study on the same sample as a function of the FEL wavelength is needed to draw a consistent conclusion. We also discuss how the advances in the performance of the FELs, in terms of generation of fully coherent photon pulses and multi-color FEL emission, may push the development of original experimental strategies to study matter at the femtosecond-nanometer time-length scales, with the unique option of element and chemical state specificity. This would allow the development of advanced experimental tools based on wave-mixing processes, which may have a tremendous impact in the study of a large array of phenomena, ranging from nano-dynamics in complex materials to charge and energy transfer processes.

  1. Short pulse free electron laser amplifier

    DOEpatents

    Schlitt, Leland G.; Szoke, Abraham

    1985-01-01

    Method and apparatus for amplification of a laser pulse in a free electron laser amplifier where the laser pulse duration may be a small fraction of the electron beam pulse duration used for amplification. An electron beam pulse is passed through a first wiggler magnet and a short laser pulse to be amplified is passed through the same wiggler so that only the energy of the last fraction, f, (f<1) of the electron beam pulse is consumed in amplifying the laser pulse. After suitable delay of the electron beam, the process is repeated in a second wiggler magnet, a third, . . . , where substantially the same fraction f of the remainder of the electron beam pulse is consumed in amplification of the given short laser pulse in each wiggler magnet region until the useful electron beam energy is substantially completely consumed by amplification of the laser pulse.

  2. IFEL driven mode locked free electron laser

    NASA Astrophysics Data System (ADS)

    Sudar, Nicholas; Musumeci, Pietro; Duris, Joe

    2014-12-01

    The x-ray free electron laser (FEL) has provided modern science with a tuneable source of high frequency, high power, coherent radiation. By manipulating the classic FEL set up, we can decrease the space required to build these machines while gaining control over the temporal and spectral structures of the outcoming radiation. In this paper we investigate a modelocked FEL with an input electron beam that has been accelerated to high energies through an inverse free electron laser (IFEL). We show that we can take advantage of the properties of the output beam from the IFEL to seed a modelocked FEL and obtain a series of periodically spaced, short pulses of coherent radiation.

  3. Long range coherence in free electron lasers

    NASA Technical Reports Server (NTRS)

    Colson, W. B.

    1984-01-01

    The simple free electron laser (FEL) design uses a static, periodic, transverse magnetic field to undulate relativistic electrons traveling along its axis. This allows coupling to a co-propagating optical wave and results in bunching to produce coherent radiation. The advantages of the FEL are continuous tunability, operation at wavelengths ranging from centimeters to angstroms, and high efficiency resulting from the fact that the interaction region only contains light, relativistic electrons, and a magnetic field. Theoretical concepts and operational principles are discussed.

  4. Free Electron Laser Research in Europe.

    DTIC Science & Technology

    1983-03-03

    necessar and identifi by block mtiwbmer Free electron laser Relativistic electron beam Gain Undulator Stimulated emission Wiggler magnet Spontaneous...lectron Beam, P 473. pass through a wiggler magnet K. Felch, L. Vallier, and which has a periodic transverse J.M. Ruzzi, Col ective Free- field. When...the electron beam is 7T-7 ot on Taspr in Re. onant Pump considered, the fiele of the Ce )d :t 0 Exper rt and wiggler magnet is equivalent to a 7hecnr

  5. High power induction free electron laser

    NASA Astrophysics Data System (ADS)

    Miller, John L.

    1988-12-01

    Free electron laser (FEL) amplifiers driven by linear induction accelerators have considerable potential for scaling to high average powers. The high electron beam current produces large single pass gain and extraction efficiency, resulting in high peak power. The pulse repetition frequency scaling is limited primarily by accelerator and pulsed power technology. Two FEL experiments have been performed by the Beam Research Program at the Lawrence Livermore National Laboratory (LLNL): The ELF experiment used the 3.5-MeV beam from the Experimental Test Accelerator (ETA) and operated at a wavelength of 8.6 mm. This device achieved an overall single-pass gain of 45 dB, an output power of 1.5 GW, and an extraction efficiency of 35 percent. The microwave beam was confined in a waveguide in the 4-m-long wiggler. The PALADIN experiment uses the 45-MeV beam from the Advanced Test Accelerator and operates at a wavelength of 10.6 micrometers. Using a 15-m long wiggler a single pass gain of 27 dB was produced. Gain guiding was observed to confine the amplified beam within a beam tube that had a Fresnel number less than 1. The results of these experiments have been successfully modeled using a three dimensional particle simulation code. The Program also has ongoing efforts to develop wiggler, pulsed power and induction linac technology. A focus of much of this work is the ETA-II accelerator, which incorporates magnetic pulse compression drivers. One application of ETA-II will be to drive a 1 mm wavelength FEL. The microwave output will be used for a plasma heating experiment.

  6. High Power Induction Free Electron Laser

    NASA Astrophysics Data System (ADS)

    Miller, John L.

    1989-07-01

    Free electron laser (FEL) amplifiers driven by linear induction accelerators have considerable potential for scaling to high average powers. The high electron beam current produces large single pass gain and extraction efficiency, resulting in high peak power. The pulse repetition frequency scaling is limited primarily by accelerator and pulsed power technology. Two FEL experiments have been performed by the Beam Research Program at the Lawrence Livermore National Laboratory (LLNL): The ELF experiment used the 3.5-MeV beam from the Experimental Test Accelerator (ETA) and operated at a wavelength of 8.6 mm. This device achieved an overall single-pass gain of 45 dB, an output power of 1.5 GW, and an extraction efficiency of 35%. The microwave beam was confined in a waveguide in the 4-m-long wiggler. The PALADIN experiment uses the 45-MeV beam from the Advanced Test Accelerator and operates at a wavelength of 10.6 IA. Using a 15-m long wiggler a single pass gain of 27 dB was produced. Gain guiding was observed to confine the amplified beam within a beam tube that had a Fresnel number less than 1. The results of these expriments have been successfully modeled using a three dimensional particle simulation code. The Program also has ongoing efforts to develop wiggler, pulsed power and induction linac technology. A focus of much of this work is the ETA-II accelerator, which incorporates magnetic pulse compression drivers. One application of ETA-II will be to drive a 1 mm wavelength FEL. The microwave output will be used for a plasma heating experiment.

  7. Smith-Purcell free-electron laser

    SciTech Connect

    Woods, K.J.; Walsh, J.E.

    1995-12-31

    The term Smith-Purcell free electron laser can be employed generally to describe any coherent radiation source in which a diffraction grating is used to couple an electron beam with the electromagnetic field. To date, most practical developments of this concept have focused on devices which operate in the millimeter spectral regime. In this paper construction of a Smith-Purcell free-electron laser operating in the far-infrared (FIR) region using a novel resonator cavity design and the electron beam from a low energy (0.5-5 MeV) radio-frequency accelerator will be discussed. A tunable source in this region would have many applications and since the beam energy is low, the small size and low overall cost of such a device would make it a laboratory instrument. Current projects which are progressing towards developing a FIR source are the programs at Stanford and CREOL. Both of these projects are using permanent magnet undulators to couple the electron beam with the electromagnetic field. An alternative approach is to use an electron beam passing over a diffraction grating as the radiating mechanism. This phenomenon is known as Smith-Purcell radiation and was first demonstrated for incoherent emission at visible wavelengths. The addition of feedback enhances the stimulated component of the emission which leads to the growth of coherence. Recent calculations for spontaneous emission have shown that the wiggler parameter and the grating efficiency are analogous. This result has important implications for the development of a Smith-Purcell FEL because a grating based free-electron laser would offer a greater range of tunability at a lower cost than its wiggler based counterpart.

  8. Kinetic theory of free electron lasers

    SciTech Connect

    Hafizi, B.; Roberson, C.W.

    1995-12-31

    We have developed a relativistic kinetic theory of free electron lasers (FELs). The growth rate, efficiency, filling factor and radius of curvature of the radiation wave fronts are determined. We have used the theory to examine the effects of beam compression on growth rate. The theory has been extended to include self field effects on FEL operation. These effects are particularly important in compact, low voltage FELs. The surprising result is that the self field contribution to the beam quality is opposite to the emittance contribution. Hence self fields can improve beam quality, particularly in compact, low voltage FELs.

  9. Free electron laser with masked chicane

    DOEpatents

    Nguyen, Dinh C.; Carlsten, Bruce E.

    1999-01-01

    A free electron laser (FEL) is provided with an accelerator for outputting electron beam pulses; a buncher for modulating each one of the electron beam pulses to form each pulse into longitudinally dispersed bunches of electrons; and a wiggler for generating coherent light from the longitudinally dispersed bunches of electrons. The electron beam buncher is a chicane having a mask for physically modulating the electron beam pulses to form a series of electron beam bunches for input to the wiggler. In a preferred embodiment, the mask is located in the chicane at a position where each electron beam pulse has a maximum dispersion.

  10. Rippled-beam free-electron laser

    SciTech Connect

    Carlsten, B.E.

    1997-10-01

    The authors describe a new microwave generation mechanism involving a scalloping annular electron beam. The beam interacts with the axial electric field of a TM{sub 0n} mode in a smooth circular waveguide through the axial free-electron laser interaction, in which the beam ripple period is synchronous with the phase slippage of the rf mode relative to the electron beam. Due to nonlinearities in the orbit equation, the interaction can be made autoresonant, where the phase and amplitude of the gain is independent of the beam energy.

  11. An inverse free electron laser accelerator experiment

    SciTech Connect

    Wernick, I.; Marshall, T.C.

    1992-12-31

    A free electron laser was configured as an autoaccelerator to test the principle of accelerating electrons by stimulated absorption of radiation ({lambda} = 1.65mm) by an electron beam (750kV) traversing an undulator. Radiation is produced in the first section of a constant period undulator (1{sub w1} = 1.43cm) and then absorbed ({approximately} 40%) in a second undulator, having a tapered period (1{sub w2} = 1.8 {minus} 2.25cm), which results in the acceleration of a subgroup ({approximately} 9%) of electrons to {approximately} 1MeV.

  12. An inverse free electron laser accelerator experiment

    SciTech Connect

    Wernick, I.; Marshall, T.C.

    1992-01-01

    A free electron laser was configured as an autoaccelerator to test the principle of accelerating electrons by stimulated absorption of radiation ([lambda] = 1.65mm) by an electron beam (750kV) traversing an undulator. Radiation is produced in the first section of a constant period undulator (1[sub w1] = 1.43cm) and then absorbed ([approximately] 40%) in a second undulator, having a tapered period (1[sub w2] = 1.8 [minus] 2.25cm), which results in the acceleration of a subgroup ([approximately] 9%) of electrons to [approximately] 1MeV.

  13. Free electron laser physical process code (FELPPC)

    SciTech Connect

    Thode, L.E.; Chan, K.C.D.; Schmitt, M.J.

    1995-02-01

    Even at the conceptual level, the strong coupling between subsystem elements complicates the understanding and design of a free electron laser (FEL). Given the requirements for high-performance FELS, the coupling between subsystems must be included to obtain a realistic picture of the potential operational capability. The concept of an Integrated Numerical Experiment (INEX) was implemented to accurately calculate the coupling between the FEL subsystems. During the late 1980`s, the INEX approach was successfully applied to a large number of accelerator and FEL experiments. Unfortunately, because of significant manpower and computational requirements, the integrated approach is difficult to apply to trade-off and initial design studies. However, the INEX codes provided a base from which realistic accelerator, wiggler, optics, and control models could be developed. The Free Electron Laser Physical Process Code (FELPPC) includes models developed from the INEX codes, provides coupling between the subsystem models, and incorporates application models relevant to a specific study. In other words, FELPPC solves the complete physical process model using realistic physics and technology constraints. FELPPC can calculate complex FEL configurations including multiple accelerator and wiggler combinations. When compared with the INEX codes, the subsystem models have been found to be quite accurate over many orders-of-magnitude. As a result, FELPPC has been used for the initial design studies of a large number of FEL applications: high-average-power ground, space, plane, and ship based FELS; beacon and illuminator FELS; medical and compact FELS; and XUV FELS.

  14. Rippled beam free electron Laser Amplifier

    SciTech Connect

    Carlsten, Bruce E.

    1998-04-21

    A free electron laser amplifier provides a scalloping annular electron beam that interacts with the axial electric field of a T{sub 0n} mode. A waveguide defines an axial centerline and . A solenoid arranged about the waveguide produces an axial constant magnetic field within the waveguide. An electron beam source outputs a annular electron beam that interacts with the axial magnetic field to have an equilibrium radius and a ripple radius component having a variable radius with a ripple period along the axial centerline. An rf source outputs an axial electric field that propagates within the waveguide coaxial with the electron beam and has a radial mode that interacts at the electron beam at the equilibrium radius component of the electron beam.

  15. Z-discharge free electron laser

    SciTech Connect

    Schep, T.J.; Bazylev, V.A.; Tulupov, A.V.

    1995-12-31

    A new kind of plasma based free-electron laser is proposed. An electromagnetic wave is generated by a relativistic electron beam moving along a stabilised z-discharge. The radiation wavelength is determined by the discharge current and the relativistic factor of the beam. It is shown that the interaction is based on two bunching mechanisms. One is due to the dependency of the longitudinal beam velocity on the energy of the electrons (inertial bunching). The second mechanism leads to azimuthal bunching and is related to the energy dependence of the oscillation frequency of electrons in the magnetic field of the discharge. At certain conditions both bunching mechanisms tend to compensate their mutual action and the system has an autoresonance. Near these conditions a high efficiency and, therefore, a high output power can be reached.

  16. Rippled beam free electron laser amplifier

    DOEpatents

    Carlsten, Bruce E.

    1999-01-01

    A free electron laser amplifier provides a scalloping annular electron beam that interacts with the axial electric field of a TM.sub.0n mode. A waveguide defines an axial centerline and, a solenoid arranged about the waveguide produces an axial constant magnetic field within the waveguide. An electron beam source outputs a annular electron beam that interacts with the axial magnetic field to have an equilibrium radius and a ripple radius component having a variable radius with a ripple period along the axial centerline. An rf source outputs an axial electric field that propagates within the waveguide coaxial with the electron beam and has a radial mode that interacts at the electron beam at the equilibrium radius component of the electron beam.

  17. Smith-Purcell free-electron laser

    NASA Astrophysics Data System (ADS)

    Schachter, Levi; Ron, Amiram

    1989-07-01

    The operation of a free-electron laser in an open periodic structure is analyzed. When operated as an amplifier, it is shown that exponential gain can develop in such a device. An analytic expression for this gain is presented, and it is shown that this gain decays exponentially with the beam height above the grating; the gain dependence on the beam thickness is also analyzed. As the energy extraction rate is much higher in an exponential gain regime, the operation of an oscillator based on the same concept is also investigated. In this case, the Smith-Purcell radiation 'provides the startup' through a feedback system. The minimal current needed to sustain oscillations is given in an analytical form. Numerical calculations show that this current is more than three orders of magnitude lower than that necessary for an oscillator which operates in an algebraic gain regime.

  18. The Oxford free electron laser project

    NASA Astrophysics Data System (ADS)

    Allison, W. W. M.; Brau, C. A.; Brooks, C. B.; Doucas, G.; Elgin, J. N.; Gillispie, W. A.; Holmes, A. R.; Jaroszynski, D. A.; Kimmitt, M. F.; Martin, P. F.; Mulvey, J. H.; Pidgeon, C. R.; Poole, M. W.

    1990-10-01

    It is proposed to use the Oxford 10 MV Van de Graaff accelerator as an electron beam source for a free electron laser (FEL) operating in the far infra red (FIR). The configuration and layout of the Van de Graaff make it very suitable for conversion, with a potentially high efficiency for electron beam recovery. Using a 2 m long wiggler of 34 mm period, the FEL would operate in the 60-300 μm wavelength band, with extension down to 30 μm on the 3rd harmonic. When constructed, the FEL will support a programme of FEL research and development, concentrating at first on investigations of behaviour in the moderately high-gain regime (˜ 100% per pass) and mechanisms for lasing on higher harmonics. It will also be the basis for a national UK user facility in the FIR.

  19. Advances in X-ray free electron laser (XFEL) diffraction data processing applied to the crystal structure of the synaptotagmin-1 / SNARE complex.

    PubMed

    Lyubimov, Artem Y; Uervirojnangkoorn, Monarin; Zeldin, Oliver B; Zhou, Qiangjun; Zhao, Minglei; Brewster, Aaron S; Michels-Clark, Tara; Holton, James M; Sauter, Nicholas K; Weis, William I; Brunger, Axel T

    2016-10-12

    X-ray free electron lasers (XFELs) reduce the effects of radiation damage on macromolecular diffraction data and thereby extend the limiting resolution. Previously, we adapted classical post-refinement techniques to XFEL diffraction data to produce accurate diffraction data sets from a limited number of diffraction images (Uervirojnangkoorn et al., 2015), and went on to use these techniques to obtain a complete data set from crystals of the synaptotagmin-1 / SNARE complex and to determine the structure at 3.5 Å resolution (Zhou et al., 2015). Here, we describe new advances in our methods and present a reprocessed XFEL data set of the synaptotagmin-1 / SNARE complex. The reprocessing produced small improvements in electron density maps and the refined atomic model. The maps also contained more information than those of a lower resolution (4.1 Å) synchrotron data set. Processing a set of simulated XFEL diffraction images revealed that our methods yield accurate data and atomic models.

  20. Quantum Mechanical Aspects of Free Electron Lasers.

    NASA Astrophysics Data System (ADS)

    Saritepe, Selcuk

    Scope of study. A 2-D quantum theory of the Free Electron Laser (FEL) has been developed based on the solutions of Dirac equation for the motion of electrons moving in various wiggler geometries, uniform, tapered and enhanced by an axial guide field. It is shown that these solutions can be written in terms of Mathieu functions of fractional order. Using these solutions a perturbational analysis is carried out to calculate the frequencies and the gain of the FEL in each magnet configuration. Finally, an optical model for the FEL interaction is developed to explain the saturation behaviour and the short-pulse effects such as Laser Lethargy. Findings and conclusions. It is found that the quantum mechanical effects due to transverse momentum correction were gamma (Lorentz factor) times larger than the quantum recoil and spin effects and therefore important for the short wavelength FELs. These quantum mechanical effects cause a broadening in the spontaneous emission lineshape, a decrease in gain and an increase in the rate of harmonic frequency generation. In the presence of an axial field, gain is increased, harmonic frequency rate is reduced and Dirac solutions exhibit instability. The optical model developed in this thesis correctly predicts the oscillator rise time and uses a simpler algorithm to calculate the nonlinear saturation behaviour. Optical model also incorporates inhomogeneous broadening and quantum mechanical effects and explains the Laser Lethargy effect as an optical pulse compression phenomenon.

  1. Inverse Free Electron Laser Accelerator Development

    NASA Astrophysics Data System (ADS)

    van Steenbergen, Arie

    1997-05-01

    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. The studies focused on the development of a low energy (few GeV), high gradient, multistage linear accelerator. As part of this program a proof-of-principle experiment with a single module accelerator unit has been successfully carried out. The IFEL accelerator made use of the 40 MeV Linac beam and high power CO2 laser beam of the BNL's Accelerator Test Facility, in conjunction with a fast excitation, tapered period, beam wiggler. Basic aspects of the design of this single module IFEL accelerator will be presented, together with the experimental results of Δ E/E as a function of the IFEL parameters, which in comparison with analytical and 1, 3-D numerical simulations clearly establish the IFEL character of the electron - EM wave energy exchange, permitting thereby scaling to higher laser power magnitude and acceleration gradients. In addition, planned near term IFEL accelerator development will be indicated, incorporating the use of the IFEL as a beam prebuncher preceding an Inverse Cherenkov Accelerator, and the use of two IFEL modules in cascade in order to more realistically test the feasibility of a multi-module IFEL accelerator. New experimental results can be found at the IFEL World-Wide-Web page.

  2. Workshop on scientific and industrial applications of free electron lasers

    SciTech Connect

    Difilippo, F.C. ); Perez, R.B. Tennessee Univ., Knoxville, TN )

    1990-05-01

    A Workshop on Scientific and Industrial Applications of Free Electron Lasers was organized to address potential uses of a Free Electron Laser in the infrared wavelength region. A total of 13 speakers from national laboratories, universities, and the industry gave seminars to an average audience of 30 persons during June 12 and 13, 1989. The areas covered were: Free Electron Laser Technology, Chemistry and Surface Science, Atomic and Molecular Physics, Condensed Matter, and Biomedical Applications, Optical Damage, and Optoelectronics.

  3. Analysis of the ac free electron laser

    NASA Astrophysics Data System (ADS)

    Chung, Tae Hung; Lee, Jin Hyun

    1990-06-01

    An ac free-electron laser (FEL) with a superconductor cavity and a FEL with a plasma wave wiggler are analyzed. The ac FEL has a small effective wiggler wavelength and higher wiggler strength. Therefore, it can supply high-power coherent radiation with a short wavelength. From the linear fluid theory and Maxwell's equations, the dispersion relation is derived. When the coupling term is much less than unity, the growth rate of electromagnetic instability is calculated. The intrinsic efficiency of radiation production is also estimated. For the small-signal gain regime, the gain coefficient is formulated. In a FEL with a plasma wiggler, the electron beam passing through the wiggler plasma might begin to thermalize due to various particle-particle and wave-particle interactions. To avoid such interactions, the electron beam should be bunched and narrower than the skin depth. It has been found that the growth rate has a linear dependence on the amplitude of the electric wiggler and decreases with increasing beam energy. The intrinsic efficiency of radiation production decreases with increasing beam energy. In a FEL with a plasma wiggler, the efficiency is enhanced by an increase in the electron beam density.

  4. Synchrotron Facilities and Free Electron Lasers

    SciTech Connect

    Vaclav, Vylet; Liu, James; /SLAC

    2007-12-21

    Synchrotron radiation (SR) is electromagnetic radiation emitted when a charged particle travels along a curved trajectory. Initially encountered as a nuisance around orbits of high energy synchrotron accelerators, it gradually became an indispensable research tool in many applications: crystallography, X-ray lithography, micromechanics, structural biology, microprobe X-ray experiments, etc. So-called first generation SR sources were exploiting SR in parasitic mode at electron accelerators built to study particle collisions. The second generation of SR sources was the first facilities solely devoted to SR production. They were optimized to achieve stable high currents in the accelerator ring to achieve substantially higher photon flux and to provide a large number of SR beam lines for users. Third generation sources were further optimized for increased brilliance, i.e. with photons densely packed into a beam of very small cross-sectional area and minimal angular divergence (see the Appendix for more detailed definitions of flux, brightness and brilliance) and makes extensive use of the insertion devices such as wigglers and undulators. Free Electron Lasers (FELs), the fourth generation SR sources, open new research possibilities by offering extremely short pulses of extremely bright and coherent radiation. The number of SR sources around the world now probably exceeds 100. These facilities vary greatly in size, energy of the electron (or positron) beams, range of photon energies and other characteristics of the photon beams produced. In what follows we will concentrate on describing some common aspects of SR facilities, their operation modes and specific radiation protection aspects.

  5. Free electron laser lithotripsy: threshold radiant exposures.

    PubMed

    Chan, K F; Hammer, D X; Choi, B; Teichman, J M; McGuff, H S; Pratisto, H; Jansen, E D; Welch, A J

    2000-03-01

    To determine the threshold radiant exposures (J/cm2) needed for ablation or fragmentation as a function of infrared wavelengths on various urinary calculi and to determine if there is a relation between these thresholds and lithotripsy efficiencies with respect to optical absorption coefficients. Human calculi composed of uric acid, calcium oxalate monohydrate (COM), cystine, or magnesium ammonium phosphate hexahydrate (MAPH) were used. The calculi were irradiated in air with the free electron laser (FEL) at six wavelengths: 2.12, 2.5, 2.94, 3.13, 5, and 6.45 microm. Threshold radiant exposures increased as optical absorption decreased. At the near-infrared wave-lengths with low optical absorption, the thresholds were >1.5 J/cm2. The thresholds decreased below 0.5 J/cm2 for regions of high absorption for all the calculus types. Thresholds within the high-absorption regions were statistically different from those in the low-absorption regions, with P values much less than 0.05. Optical absorption coefficients or threshold radiant exposures can be used to predict lithotripsy efficiencies. For low ablation thresholds, smaller radiant exposures were required to achieve breakdown temperatures or to exceed the dynamic tensile strength of the material. Therefore, more energy is available for fragmentation, resulting in higher lithotripsy efficiencies.

  6. Smith-Purcell free-electron laser

    SciTech Connect

    Schachter, L.; Ron, A.

    1989-07-15

    We analyze the operation of a free-electron laser in an open periodicstructure. When operated as an amplifier, it is shown that exponential gain candevelop in such a device. An analytic expression for this gain is presented,and it is shown that this gain decays exponentially with the beam height abovethe grating; the gain dependence on the beam thickness is also analyzed. As theenergy extraction rate is much higher in an exponential gain regime, we alsoinvestigate the operation of an oscillator based on the same concept. In thiscase, the Smith-Purcell radiation ''provides the startup'' through a feedbacksystem. The latter consists of several mirrors, which are placed in such a waythat (1) only a wave with the desired frequency develops and, at the same time,(2) small deviations in the wave parameters due to the wave-beam interaction donot cause deflection of the wave from the feedback loop. The minimal currentneeded to sustain oscillations is given in an analytical form. Numericalcalculations show that this current is more than three orders of magnitudelower than that necessary for an oscillator which operates in an algebraic gainregime.

  7. Free electron lasers with small period wigglers

    NASA Astrophysics Data System (ADS)

    Antonsen, T. M., Jr.; Booske, J. H.; Destler, W. W.; Granatstein, V. L.; Mayergoyz, I. D.; Ott, E.

    1989-05-01

    Progress of research on a short period wiggler (SPW) free electron laser (FEL) with a sheet electron beam is reviewed. Most of the recent work has concentrated on addressing thermal engineering issued in the device. This particular emphasis was particularly stimulated by an evaluation by Panel XXI for the Magnetic Fusion Advisory Committee which stated that there are serious thermal management engineering uncertainties in the electron gun, the microwave cavity, and the wiggler that will need to be addressed for CW operation. In the panel's judgment, these thermal problems are likely to be insurmountable for fusion applications. In fact, recent experimental and theoretical results challenge this judgment. For example, our most recent conceptual designs involve small-to-negligible RF losses in the cavity walls. In addition, we have convincingly established that for electron beams of quality achievable with thermionic Pierce guns, body currents should be negligible to nonexistent, thus ensuring a thermally stable cavity. These discoveries, as well as other research progress, are reviewed in detail in the following report. Plans are described for a pulsed (100 ns) proof-of-principle lasing experiment to be conducted during the remainder of this fiscal year. In addition, we present a revised statement of work and budget for the follow-on year of the current grant. These proposed tasks will address the remaining risk issues for an ERCH source based on the SPW sheet-beam FEL. Upon the completion of those tasks, sufficient information will exist to confidently assess the feasibility of the proposed concept.

  8. X-ray Free-electron Lasers

    SciTech Connect

    Feldhaus, J.; Arthur, J.; Hastings, J.B.; /SLAC

    2007-02-23

    In a free-electron laser (FEL) the lasing medium is a high-energy beam of electrons flying with relativistic speed through a periodic magnetic field. The interaction between the synchrotron radiation that is produced and the electrons in the beam induces a periodic bunching of the electrons, greatly increasing the intensity of radiation produced at a particular wavelength. Depending only on a phase match between the electron energy and the magnetic period, the wavelength of the FEL radiation can be continuously tuned within a wide spectral range. The FEL concept can be adapted to produce radiation wavelengths from millimeters to Angstroms, and can in principle produce hard x-ray beams with unprecedented peak brightness, exceeding that of the brightest synchrotron source by ten orders of magnitude or more. This paper focuses on short-wavelength FELs. It reviews the physics and characteristic properties of single-pass FELs, as well as current technical developments aiming for fully coherent x-ray radiation pulses with pulse durations in the 100 fs to 100 as range. First experimental results at wavelengths around 100 nm and examples of scientific applications planned on the new, emerging x-ray FEL facilities are presented.

  9. Biophysics applications of free-electron lasers

    NASA Astrophysics Data System (ADS)

    Austin, Robert H.

    1993-07-01

    There has been a significant financial effort poured into the technology of the Free Electron Laser (FEL) over the last 15 years or so. Much of that money was spent in the hopes that the FEL would be a key element in the Strategic Defense Initiative, but a small fraction of money was allocated for the Medical FEL program. The Medical FELs program was aimed at exploring how the unique capabilities of the FEL could be utilized in medical applications. Part of the Medical FEl effort has been in clinical applications, but some of the effort has also been put into exploring applications of the FEL for fundamental biological physics. It is the purpose of this brief text to outline some of the fundamental biophysics I have done, and some plans we have for the future. Since the FEL is (still) considered to be an avant garde device, the reader should not be surprised to find that much of the work proposed here is also rather radical and avant garde.

  10. Laser Phase Errors in Seeded Free Electron Lasers

    SciTech Connect

    Ratner, D.; Fry, A.; Stupakov, G.; White, W.; /SLAC

    2012-04-17

    Harmonic seeding of free electron lasers has attracted significant attention as a method for producing transform-limited pulses in the soft x-ray region. Harmonic multiplication schemes extend seeding to shorter wavelengths, but also amplify the spectral phase errors of the initial seed laser, and may degrade the pulse quality and impede production of transform-limited pulses. In this paper we consider the effect of seed laser phase errors in high gain harmonic generation and echo-enabled harmonic generation. We use simulations to confirm analytical results for the case of linearly chirped seed lasers, and extend the results for arbitrary seed laser envelope and phase.

  11. Operation of higher harmonic oscillations in free-electron lasers.

    PubMed

    Sei, N; Ogawa, H; Yamada, K

    2012-01-02

    We report for the first time the experimental achievement of a seventh-harmonic free-electron laser (FEL) oscillation. The measured FEL gains and average FEL powers for higher harmonics were identical to those calculated by a one-dimensional FEL theory. The measured linewidths of the higher-harmonic FELs were narrower than that of the fundamental FEL owing to the narrower spectral widths of the spontaneous emissions. By applying the higher-harmonic FEL oscillation to a resonator-type FEL with an advanced accelerator, an x-ray FEL oscillator can be realized at lower electron-beam energy.

  12. Ignition feedback regenerative free electron laser (FEL) amplifier

    DOEpatents

    Kim, Kwang-Je; Zholents, Alexander; Zolotorev, Max

    2001-01-01

    An ignition feedback regenerative amplifier consists of an injector, a linear accelerator with energy recovery, and a high-gain free electron laser amplifier. A fraction of the free electron laser output is coupled to the input to operate the free electron laser in the regenerative mode. A mode filter in this loop prevents run away instability. Another fraction of the output, after suitable frequency up conversion, is used to drive the photocathode. An external laser is provided to start up both the amplifier and the injector, thus igniting the system.

  13. Free Electron Laser Analysis For the Innovative Navy Prototype

    DTIC Science & Technology

    2008-03-01

    are oscillating at microwave frequencies, but the laser operates at infrared frequencies due to relativistic Doppler shifts [1]. 2. Microscopic...Applications of a Free Electron Laser Lidar ”, Geoscience and Remote Sensing Symposium, 2000, vol. 6, pp 2471-2473, 24-28 July 2000. [21] Frank Carroll...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS Approved for public release; distribution is unlimited FREE ELECTRON LASER

  14. Advances in X-ray free electron laser (XFEL) diffraction data processing applied to the crystal structure of the synaptotagmin-1 / SNARE complex

    PubMed Central

    Lyubimov, Artem Y; Uervirojnangkoorn, Monarin; Zeldin, Oliver B; Zhou, Qiangjun; Zhao, Minglei; Brewster, Aaron S; Michels-Clark, Tara; Holton, James M; Sauter, Nicholas K; Weis, William I; Brunger, Axel T

    2016-01-01

    X-ray free electron lasers (XFELs) reduce the effects of radiation damage on macromolecular diffraction data and thereby extend the limiting resolution. Previously, we adapted classical post-refinement techniques to XFEL diffraction data to produce accurate diffraction data sets from a limited number of diffraction images (Uervirojnangkoorn et al., 2015), and went on to use these techniques to obtain a complete data set from crystals of the synaptotagmin-1 / SNARE complex and to determine the structure at 3.5 Å resolution (Zhou et al., 2015). Here, we describe new advances in our methods and present a reprocessed XFEL data set of the synaptotagmin-1 / SNARE complex. The reprocessing produced small improvements in electron density maps and the refined atomic model. The maps also contained more information than those of a lower resolution (4.1 Å) synchrotron data set. Processing a set of simulated XFEL diffraction images revealed that our methods yield accurate data and atomic models. DOI: http://dx.doi.org/10.7554/eLife.18740.001 PMID:27731796

  15. Free electron laser using Rf coupled accelerating and decelerating structures

    DOEpatents

    Brau, Charles A.; Swenson, Donald A.; Boyd, Jr., Thomas J.

    1984-01-01

    A free electron laser and free electron laser amplifier using beam transport devices for guiding an electron beam to a wiggler of a free electron laser and returning the electron beam to decelerating cavities disposed adjacent to the accelerating cavities of the free electron laser. Rf energy is generated from the energy depleted electron beam after it emerges from the wiggler by means of the decelerating cavities which are closely coupled to the accelerating cavities, or by means of a second bore within a single set of cavities. Rf energy generated from the decelerated electron beam is used to supplement energy provided by an external source, such as a klystron, to thereby enhance overall efficiency of the system.

  16. Wiggler plane focusing in a linear free electron laser

    DOEpatents

    Scharlemann, Ernst T.

    1988-01-01

    Free electron laser apparatus that provides a magnetic centering force to turn or focus a non-axial electron toward the longitudinal axis as desired. The focusing effect is provided by wiggler magnet pole faces that are approximately parabolically shaped.

  17. Single electron beam rf feedback free electron laser

    DOEpatents

    Brau, C.A.; Stein, W.E.; Rockwood, S.D.

    1981-02-11

    A free electron laser system and electron beam system for a free electron laser which uses rf feedback to enhance efficiency are described. Rf energy is extracted from a single electron beam by decelerating cavities and energy is returned to accelerating cavities using rf returns, such as rf waveguides, rf feedthroughs, resonant feedthroughs, etc. This rf energy is added to rf klystron energy to reduce the required input energy and thereby enhance energy efficiency of the system.

  18. Metal Photocathodes for Free Electron Laser Applications

    NASA Astrophysics Data System (ADS)

    Greaves, Corin Michael Ricardo

    Synchrotron x-ray radiation sources have revolutionized many areas of science from elucidating the atomic structure of proteins to understanding the electronic structure of complex materials such as the cuprate superconductors. In a Free Electron Laser (FEL), the main difference to the synchrotron radiation mechanism is that the light field acts on the electron beam, over a long distance in an undulator, and causes electron bunching at the optical wavelength. Electrons in different parts of the electron bunch are therefore correlated, and so emit coherently, with a brightness that scales as the square of the number of electrons. In order to lase, the electron beam in a FEL must have a transverse geometric emittance less than the wavelength of the light to be produced. For the generation of x-ray wavelengths, this is one of the most difficult challenges in the design and construction of a FEL. The geometric emittance can be "compressed" by acceleration to very high energy, but with the penalty of very large physical size and very large cost. The motivation for this work was provided by the desire to investigate the fundamental origin of the emittance of an electron beam as it is born at a photocathode. If this initial, or "thermal" emittance can be reduced, the energy, scale and cost of accelerators potentially would be reduced. As the LCLS used copper as its photocathode, this material was the one studied in this work. Copper was used in the LCLS as it represented a "robust" material that could stand the very high accelerating gradients used in the photoinjector of the FEL. Metals are also prompt photoemitters, and so can be used to produce very short electron bunches. This can be a useful property for creation of extremely short FEL pulses, and also for creation of beams that are allowed to expand under space charge forces, but in a way that results in linear fields, allowing subsequent recompression. An ideal photocathode for FEL photoinjector should have high

  19. High-gain harmonic-generation free-electron laser

    PubMed

    Yu; Babzien; Ben-Zvi; DiMauro; Doyuran; Graves; Johnson; Krinsky; Malone; Pogorelsky; Skaritka; Rakowsky; Solomon; Wang; Woodle; Yakimenko; Biedron; Galayda; Gluskin; Jagger; Sajaev; Vasserman

    2000-08-11

    A high-gain harmonic-generation free-electron laser is demonstrated. Our approach uses a laser-seeded free-electron laser to produce amplified, longitudinally coherent, Fourier transform-limited output at a harmonic of the seed laser. A seed carbon dioxide laser at a wavelength of 10.6 micrometers produced saturated, amplified free-electron laser output at the second-harmonic wavelength, 5.3 micrometers. The experiment verifies the theoretical foundation for the technique and prepares the way for the application of this technique in the vacuum ultraviolet region of the spectrum, with the ultimate goal of extending the approach to provide an intense, highly coherent source of hard x-rays.

  20. Femtosecond all-optical synchronization of an X-ray free-electron laser

    DOE PAGES

    Schulz, S.; Grguraš, I.; Behrens, C.; ...

    2015-01-20

    Many advanced applications of X-ray free-electron lasers require pulse durations and time resolutions of only a few femtoseconds. To generate these pulses and to apply them in time-resolved experiments, synchronization techniques that can simultaneously lock all independent components, including all accelerator modules and all external optical lasers, to better than the delivered free-electron laser pulse duration, are needed. Here we achieve all-optical synchronization at the soft X-ray free-electron laser FLASH and demonstrate facility-wide timing to better than 30 fs r.m.s. for 90 fs X-ray photon pulses. Crucially, our analysis indicates that the performance of this optical synchronization is limited primarilymore » by the free-electron laser pulse duration, and should naturally scale to the sub-10 femtosecond level with shorter X-ray pulses.« less

  1. Femtosecond all-optical synchronization of an X-ray free-electron laser

    SciTech Connect

    Schulz, S.; Grguraš, I.; Behrens, C.; Bromberger, H.; Costello, J. T.; Czwalinna, M. K.; Felber, M.; Hoffmann, M. C.; Ilchen, M.; Liu, H. Y.; Mazza, T.; Meyer, M.; Pfeiffer, S.; Prędki, P.; Schefer, S.; Schmidt, C.; Wegner, U.; Schlarb, H.; Cavalieri, A. L.

    2015-01-20

    Many advanced applications of X-ray free-electron lasers require pulse durations and time resolutions of only a few femtoseconds. To generate these pulses and to apply them in time-resolved experiments, synchronization techniques that can simultaneously lock all independent components, including all accelerator modules and all external optical lasers, to better than the delivered free-electron laser pulse duration, are needed. Here we achieve all-optical synchronization at the soft X-ray free-electron laser FLASH and demonstrate facility-wide timing to better than 30 fs r.m.s. for 90 fs X-ray photon pulses. Crucially, our analysis indicates that the performance of this optical synchronization is limited primarily by the free-electron laser pulse duration, and should naturally scale to the sub-10 femtosecond level with shorter X-ray pulses.

  2. Femtosecond all-optical synchronization of an X-ray free-electron laser

    PubMed Central

    Schulz, S.; Grguraš, I.; Behrens, C.; Bromberger, H.; Costello, J. T.; Czwalinna, M. K.; Felber, M.; Hoffmann, M. C.; Ilchen, M.; Liu, H. Y.; Mazza, T.; Meyer, M.; Pfeiffer, S.; Prędki, P.; Schefer, S.; Schmidt, C.; Wegner, U.; Schlarb, H.; Cavalieri, A. L.

    2015-01-01

    Many advanced applications of X-ray free-electron lasers require pulse durations and time resolutions of only a few femtoseconds. To generate these pulses and to apply them in time-resolved experiments, synchronization techniques that can simultaneously lock all independent components, including all accelerator modules and all external optical lasers, to better than the delivered free-electron laser pulse duration, are needed. Here we achieve all-optical synchronization at the soft X-ray free-electron laser FLASH and demonstrate facility-wide timing to better than 30 fs r.m.s. for 90 fs X-ray photon pulses. Crucially, our analysis indicates that the performance of this optical synchronization is limited primarily by the free-electron laser pulse duration, and should naturally scale to the sub-10 femtosecond level with shorter X-ray pulses. PMID:25600823

  3. Femtosecond all-optical synchronization of an X-ray free-electron laser.

    PubMed

    Schulz, S; Grguraš, I; Behrens, C; Bromberger, H; Costello, J T; Czwalinna, M K; Felber, M; Hoffmann, M C; Ilchen, M; Liu, H Y; Mazza, T; Meyer, M; Pfeiffer, S; Prędki, P; Schefer, S; Schmidt, C; Wegner, U; Schlarb, H; Cavalieri, A L

    2015-01-20

    Many advanced applications of X-ray free-electron lasers require pulse durations and time resolutions of only a few femtoseconds. To generate these pulses and to apply them in time-resolved experiments, synchronization techniques that can simultaneously lock all independent components, including all accelerator modules and all external optical lasers, to better than the delivered free-electron laser pulse duration, are needed. Here we achieve all-optical synchronization at the soft X-ray free-electron laser FLASH and demonstrate facility-wide timing to better than 30 fs r.m.s. for 90 fs X-ray photon pulses. Crucially, our analysis indicates that the performance of this optical synchronization is limited primarily by the free-electron laser pulse duration, and should naturally scale to the sub-10 femtosecond level with shorter X-ray pulses.

  4. Threshold characteristics of free electron lasers without inversion

    NASA Astrophysics Data System (ADS)

    Klochkov, Dmitry N.; Oganesyan, Koryun B.; Rostovtsev, Yuri V.; Kurizki, Gershon

    2014-12-01

    The interaction between noncolinear laser and relativistic electron beams in a static magnetic undulator has been studied within the framework of dispersion equations. For a free-electron laser without inversion (FELWI), the threshold parameters are found. The large-amplification regime should be used to bring an FELWI above the threshold laser power.

  5. Ultrashort laser pulse driven inverse free electron laser accelerator experiment

    DOE PAGES

    Moody, J. T.; Anderson, S. G.; Anderson, G.; ...

    2016-02-29

    In this paper we discuss the ultrashort pulse high gradient Inverse Free Electron laser accelerator experiment carried out at the Lawrence Livermore National Laboratory which demonstrated gra- dients exceeding 200 MV/m using a 4 TW 100 fs long 800 nm Ti:Sa laser pulse. Due to the short laser and electron pulse lengths, synchronization was determined to be one of the main challenges in this experiment. This made necessary the implementation of a single-shot, non destructive, electro-optic sampling based diagnostics to enable time-stamping of each laser accelerator shot with < 100 fs accuracy. The results of this experiment are expected tomore » pave the way towards the development of future GeV-class IFEL accelerators.« less

  6. Ultrashort laser pulse driven inverse free electron laser accelerator experiment

    NASA Astrophysics Data System (ADS)

    Moody, J. T.; Anderson, S. G.; Anderson, G.; Betts, S.; Fisher, S.; Tremaine, A.; Musumeci, P.

    2016-02-01

    In this paper we discuss the ultrashort pulse high gradient inverse free electron laser accelerator experiment carried out at the Lawrence Livermore National Laboratory which demonstrated gradients exceeding 200 MV /m using a 4 TW 100 fs long 800 nm Ti :Sa laser pulse. Due to the short laser and electron pulse lengths, synchronization was determined to be one of the main challenges in this experiment. This made necessary the implementation of a single-shot, nondestructive, electro-optic sampling based diagnostics to enable time-stamping of each laser accelerator shot with <100 fs accuracy. The results of this experiment are expected to pave the way towards the development of future GeV-class IFEL accelerators.

  7. A compact x-ray free electron laser

    SciTech Connect

    Barletta, W.; Attac, M.; Cline, D.B.; Kolonko, J.; Wang, X.; Bhowmik, A.; Bobbs, B.; Cover, R.A.; Dixon, F.P.; Rakowsky, G.; Gallardo, J.; Pellegrini, C.; Westenskow, G.

    1988-09-09

    We present a design concept and simulation of the performance of a compact x-ray, free electron laser driven by ultra-high gradient rf-linacs. The accelerator design is based on recent advances in high gradient technology by a LLNL/SLAC/LBL collaboration and on the development of bright, high current electron sources by BNL and LANL. The GeV electron beams generated with such accelerators can be concerted to soft x-rays in the range from 2--10 nm by passage through short period, high fields strength wigglers as are being designed at Rocketdyne. Linear light sources of this type can produce trains of picosecond (or shorter) pulses of extremely high spectral brilliance suitable for flash holography of biological specimens in vivo and for studies of fast chemical reactions. 12 refs., 8 figs., 4 tabs.

  8. A compact X-ray free electron laser

    NASA Astrophysics Data System (ADS)

    Barletta, W.; Atac, M.; Cline, D. B.; Kolonko, J.; Wang, X.; Bhowmik, A.; Bobbs, B.; Cover, R. A.; Dixon, F. P.; Rakowsky, G.

    1988-09-01

    A design concept and simulation of the performance of a compact X-ray, free electron laser driven by ultra-high gradient RF-linacs is presented. The accelerator design is based on recent advances in high gradient technology by a LLNL/SLAC/LBL collaboration and on the development of bright, high current electron sources by BNL and LANL. The GeV electron beams generated with such accelerators can be converted to soft X-rays in the range from 2 to 10 nm by passage through short period, high fields strength wigglers as are being designed at Rocketdyne. Linear light sources of this type can produce trains of picosecond (or shorter) pulses of extremely high spectral brilliance suitable for flash holography of biological specimens in vivo and for studies of fast chemical reactions.

  9. Multifrequency, single pass free electron laser

    DOEpatents

    Szoke, Abraham; Prosnitz, Donald

    1985-01-01

    A method for simultaneous amplification of laser beams with a sequence of frequencies in a single pass, using a relativistic beam of electrons grouped in a sequence of energies corresponding to the sequence of laser beam frequencies. The method allows electrons to pass from one potential well or "bucket" to another adjacent bucket, thus increasing efficiency of trapping and energy conversion.

  10. Two-dimensional optimization of free-electron-laser designs

    DOEpatents

    Prosnitz, D.; Haas, R.A.

    1982-05-04

    Off-axis, two-dimensional designs for free electron lasers are described that maintain correspondence of a light beam with a synchronous electron at an optimal transverse radius r > 0 to achieve increased beam trapping efficiency and enhanced laser beam wavefront control so as to decrease optical beam diffraction and other deleterious effects.

  11. Two-dimensional optimization of free electron laser designs

    DOEpatents

    Prosnitz, Donald; Haas, Roger A.

    1985-01-01

    Off-axis, two-dimensional designs for free electron lasers that maintain correspondence of a light beam with a "synchronous electron" at an optimal transverse radius r>0 to achieve increased beam trapping efficiency and enhanced laser beam wavefront control so as to decrease optical beam diffraction and other deleterious effects.

  12. Resonator design for a visible wavelength free-electron laser (*)

    SciTech Connect

    Bhowmik, A.; Lordi, N. . Rocketdyne Div.); Ben-Zvi, I.; Gallardo, J. )

    1990-01-01

    Design requirements for a visible wavelength free-electron laser being developed at the Accelerator Test Facility at Brookhaven National Laboratory are presented along with predictions of laser performance from 3-D numerical simulations. The design and construction of the optical resonator, its alignment and control systems are also described. 15 refs., 8 figs., 4 tabs.

  13. Midwest free-electron laser program

    NASA Astrophysics Data System (ADS)

    Cerullo, L. J.; Epstein, M.; Marhic, M. E.; Rymer, W. Z.; Spears, K. G.

    1987-03-01

    Developments in infrared waveguides for laser beam delivery include liquid core fibers, germanium coated brass guides, whisper gallery waveguides, Bragg fibers and waveguides with periodic structures. Studies of interaction of laser radiation with tissue over a broad range of wavelengths include absorption of radiant energy by chromophores in a light scattered matrix, effects of heating with pulsed Nd-YAG lasers and the use of the diffusion model of radiative transfer to optical dosimetry in clinical phototherapy. The development of picosecond laser instrumentation for neuroscience research allows for the simulation of the FEL in pulse duration, energy and wavelengths. The effects of laser-beam energy in neural tissue were investigated. These studies included the effects of CO2 laser energy on the rat spinal cord as determined by the evoked potentials recorded from dorsal white matter in the mid-thoracic cord. The latter showed no discernable effects for levels below those causing visible damage to the dorsal column white matter. These studies indicate minimal thermal effects at levels corresponding to the onset of breakdown.

  14. Multimode Simulations of Free Electron Lasers

    DTIC Science & Technology

    2002-03-01

    working on the design of a compact , high average power FEL for ship defense in collaboration with Jefferson Labs and Advanced Energy Systems [57]. The...Postgraduate School, we are currently designing a compact , megawatt average-power FEL for ship defense, in collaboration with TJNAF and Advanced Energy

  15. Short wavelength optics for future free electron lasers

    SciTech Connect

    Attwood, D.T.

    1984-04-01

    Although much free-electron laser work is directed toward achieving sufficient single-pass gain to be useful for research purposes, the availability of mirrors of high reflectance for the vacuum ultraviolet and soft x-ray regime would make resonant cavities a possibility. In addition, as in ordinary synchrotron radiation work, mirrors are required for the construction of realistic experiments and for beam manipulation purposes such as folding and extraction. The Working Group discussed a number of approaches to reflecting optics for free electron lasers, which are summarized here, and described in some detail. 16 references, 2 figures.

  16. Vanderbilt free electron laser project in biomedical and materials research

    NASA Astrophysics Data System (ADS)

    Haglund, Richard F.; Tolk, N. H.

    1988-06-01

    The Medical Free Electron Laser Program was awarded to develop, construct and operate a free-electron laser facility dedicated to biomedical and materials studies, with particular emphases on: fundamental studies of absorption and localization of electromagnetic energy on and near material surfaces, especially through electronic and other selective, non-statistical processes; non-thermal photon-materials interactions (e.g., electronic bond-breaking or vibrational energy transfer) in physical and biological materials as well as in long-wavelength biopolymer dynamics; development of FEL-based methods to study drug action and to characterize biomolecular properties and metabolic processes in biomembranes; clinical applications in otolaryngology, neurosurgery, ophthalmology and radiology stressing the use of the laser for selective laser-tissue, laser-cellular and laser-molecule interactions in both therapeutic and diagnostic modalities.

  17. Midwest Free-Electron Laser Program

    DTIC Science & Technology

    1991-12-17

    Report, December 1991 Page 9 4. Photosensitization tissue phantoms were developed for photodynamic tumor therapy ( PDT ) consisting of light scattering...preferential sodium effect can be enhanced or developed further for clinical use to provide novel interventions in anestheia and surgical trealment of...and of the laser-bioheat transfer equation with a convection boundary for incident gaussian beams; photosensitization tissue phantoms and analytical

  18. High Extraction Free-Electron Laser Experiments.

    DTIC Science & Technology

    1983-03-29

    intended to demonstrate that the tapered wiggler can provide significant electron kinectic energy extraction on a single pass through the wiggler...experiment has been constructed and initial energy extraction measurements have been made. The intent of the experiment is to demonstrate the high...laser beams making a single simultaneous pass through the wiggler. The interaction of these beams is monitored by comparison of the electron energy

  19. Midwest free-electron laser program

    NASA Astrophysics Data System (ADS)

    Cerullo, L. J.; Epstein, M.; Marhic, M. E.; Rymer, W. Z.; Spears, K. G.

    1991-12-01

    It has been shown that pulsed Nd:YAG irradiation of nervous tissue in both mammalian and frog preparations produces selective damage to conduction and axoplasmic transport in small caliber sensory afferent fibers, which may be those responsible for pain sensation. In addition, the thermal affects on peripheral nerve appear to be primarily on sodium channels. This preferential sodium effect can be enhanced or developed further for clinical use to provide novel interventions in anesthesia and surgical treatment of painful conditions. A laser system was built to simulate the high energy pulses of a low repetition rate FEL in the infrared and was used to develop the necessary techniques for the study of transient pump-probe experiments with infrared probe wavelengths. It was employed as a transient IR probe of UV laser effects in the study of metal-ligand dissociation. A novel chrono-coherent imaging technique has been developed which uses time gating with coherent holographic recording. Utilizing short pulses, such as those from the FEL, this technique should provide a means of imaging inside the skin using optical wavelengths. A unique method of short-range electron transfer across a single bond to form a dissociated ion pair has been studied as a function of solvent. Also, the laser mediated release of dye from liposomes has been investigated. Several types of flexible waveguides, suitable for the delivery of output beams of infrared FEL's tunable within the 1 to 10 micron range, have been developed.

  20. Acceleration of electrons by inverse free electron laser interaction

    NASA Astrophysics Data System (ADS)

    Musumeci, Pietro

    Laser accelerators hold the promise to constitute the future of particle accelerators. The Inverse Free Electron Laser accelerator is one of the most efficient schemes to transfer energy from very high power lasers to electron beams. This scheme uses an undulator magnet to couple the transverse electromagnetic waves to the electron motion. In this dissertation we discuss the theoretical background of the Inverse Free Electron Laser interaction and we present the simulation tool developed to study and design an Inverse Free Electron Laser accelerator. The main object of the dissertation is the discussion of the Inverse Free Electron Laser experiment at the Neptune Laboratory at UCLA where we observed an energy gain in excess of 20 MeV. In this experiment, a 14.5 MeV electron beam is injected in an undulator strongly tapered in period and field amplitude. The IFEL driver is a CO2 10.6 mum laser with power larger than 400 GW. The Rayleigh range of the laser, ˜1.8 cm, is much shorter than the undulator length so that the interaction is diffraction dominated. A few per cent of the injected particles are trapped in a stable accelerating bucket. Electron with energies up to 35 MeV are measured in a magnetic spectrometer. Experimental results on the dependence of the acceleration on injection energy, laser focus position, and laser power are discussed. Three-dimensional simulations, in good agreement with the measured electron energy spectrum, indicate that most of the acceleration occurs in the first 25 cm of the undulator, corresponding to an energy gradient larger than 70 MeV/m. The measured energy spectrum also indicates that higher harmonic Inverse Free Electron Laser interaction is taking place in the second section of the undulator. The possibility of coupling the laser wave and the electron beam on a different spectral line of the undulator radiation adds a new degree of flexibility in the design of Inverse Free Electron Laser interaction schemes and this novel

  1. Storage Ring Technology for Free Electron Lasers.

    DTIC Science & Technology

    1984-04-01

    the undulator is \\o. K = eB,,X/2", mc is a dimensionless measure of the magnetic field and is referred to as the wiggler K parameter, and nK 2 /(4 + 2K...pole-face gap of the undulator, which can ~vi~lr I tr. Th be equated to the magnetic field strength [27], and the wiggler K parameter. The resonant...rings. For SRFEL systems with linear wigglers [13] Pl.aer ma ,oPsyn. (10) The output power of the laser is Paser, the total synchrotron-radiation power

  2. Nonlinear pulse evolution in seeded free-electron laser amplifiers and in free-electron laser cascades

    SciTech Connect

    Giannessi, L.; Musumeci, P.; Spampinati, S.

    2005-08-15

    The advances in laser technology have made available very short and intense laser pulses which can be used to seed a high-gain single-pass free-electron laser (FEL) amplifier. With these seed pulses, a regime of the FEL interaction where the radiation evolution is simultaneously dominated by nonlinear effects (saturation) and time-dependent effects (slippage) can be explored. This regime is characterized by the propagation of a solitary wavelike pulse where the power of the optical wave grows quadratically with time, its pulse length decreases and the spectral bandwidth increases. We analyze the interplay between the field and particle dynamics of this propagation regime which was studied before and termed super-radiance. Furthermore we analyze the properties of the strong higher-order harmonic emission from this wave and its behavior when propagating in a cascade FEL. The super-radiant pulse is indeed capable of passing through the stages of a cascade FEL and to regenerate itself at the wavelength of the higher-order harmonic. The optical pulse obtained is shorter than a cooperation length and is strongly chirped in frequency, thus allowing further longitudinal compression down to the attosecond time scale.

  3. Design and Analysis of Megawatt Class Free Electron Laser Weapons

    DTIC Science & Technology

    2015-12-01

    DISTRIBUTION CODE A 13. ABSTRACT (maximum 200 words) Free Electron Lasers (FELs) are desirable for defense against a spectrum of threats...desirable for defense against a spectrum of threats, especially in the maritime domain, due to their all-electric nature, their wavelength tunability...7 C. ELECTROMAGNETIC FIELDS IN THE UNDULATOR ..................8 D. UNDULATOR PARAMETER

  4. Wiggler plane focusing in a linear free electron laser

    DOEpatents

    Scharlemann, E.T.

    1985-11-21

    This disclosure describes a free electron laser apparatus that provides a magnetic centering force to turn or focus a non-axial electron toward the longitudinal axis as desired. The focusing effect is provided by wiggler magnet pole faces that are approximately parabolically shaped.

  5. Wiggler plane focusing in a linear free electron laser

    DOEpatents

    Scharlemann, E.T.

    1988-02-23

    Free electron laser apparatus that provides a magnetic centering force to turn or focus a non-axial electron toward the longitudinal axis as desired. The focusing effect is provided by wiggler magnet pole faces that are approximately parabolically shaped. 5 figs.

  6. XUV/VUV free-electron laser oscillator

    SciTech Connect

    Goldstein, J.C.; Newnam, B.E.; Cooper, R.K.; Comly, J.C. Jr.

    1984-04-01

    It is shown, from computations based on a detailed theoretical model, that modest improvements in electron beam and optical mirror technologies will enable a free-electron laser, driven by an rf linear accelerator, to operate in the 50 to 200-nm range of optical wavelengths. 10 references.

  7. Laguerre-Gaussian Modes in the Free Electron Laser

    DTIC Science & Technology

    2007-06-01

    Griffiths , Introduction to Electrodynamics , Prentice Hall, 1999. 72 [15] F. L. Pedrotti, L. S. Pedrotti and L. M. Pedrotti, Introduction to Optics...PAGE INTENTIONALLY LEFT BLANK vii TABLE OF CONTENTS I. INTRODUCTION ...65 xii THIS PAGE INTENTIONALLY LEFT BLANK 1 I. INTRODUCTION The Free Electron Laser (FEL) is a source of powerful

  8. Inverse free electron laser acceleration with a square wave wiggler

    NASA Astrophysics Data System (ADS)

    Parsa, Z.; Pato, M. P.

    1997-02-01

    We present an Inverse Free Electron Laser with a Square Wave Wiggler (IFELSW) as a new acceleration scheme and show Analytically and numerically about factor of 2 gain in the energy when compared to the standard IFEL with the Sinusoidal [1] field Wiggler.

  9. The Chirped-Pulse Inverse Free-Electron Laser

    NASA Astrophysics Data System (ADS)

    Hartemann, F. V.; Landahl, E. C.; Song, L.; Troha, A. L.; van Meter, J. R.; Gibson, D. J.; Baldis Luhmann, H. A., Jr.

    1999-11-01

    The inverse free-electron laser (IFEL) concept has been demonstrated as a viable vacuum laser acceleration process; it is shown here that by using an ultrahigh-intensity chirped laser pulse, the dephasing length can be increased considerably, thus yielding high gradient IFEL acceleration. In addition, using negative dispersion focusing optics allows one to take advantage of the laser optical bandwidth and produce a chromatic line focus to maximize the accelerating field. The combination of these two novel ideas results in a compact, efficient, vacuum laser accelerator.

  10. A free-electron laser in a uniform magnetic field

    NASA Technical Reports Server (NTRS)

    Ride, S. K.; Colson, W. B.

    1979-01-01

    The study shows that a free-electron laser can operate in a uniform, longitudinal magnetic field. The fully relativistic Lorentz force equations are examined and solved order by order in a radiation field strength to obtain analytic expressions for the electron trajectory and energy as functions of initial electron position within a wavelength of light. Analytic expressions for the longitudinal and transverse bunching and for laser gain are found. The bunching of this laser process is compared to the bunching processes involved in (1) a Stanford free-electron laser and (2) a cyclotron maser. The results received can be useful in exploring light amplification in astrophysical magnetic fields, the magnetosphere, and in laboratory devices.

  11. High power free-electron laser concepts and problems

    SciTech Connect

    Goldstein, J.C.

    1995-03-01

    Free-electron lasers (FELs) have long been thought to offer the potential of high average power operation. That potential exists because of several unique properties of FELs, such as the removal of ``waste heat`` at the velocity of light, the ``laser medium`` (the electron beam) is impervious to damage by very high optical intensitites, and the technology of generating very high average power relativistic electron beams. In particular, if one can build a laser with a power extraction efficiency 11 which is driven by an electron beam of average Power P{sub EB}, one expects a laser output power of P{sub L} = {eta} P{sub EB}. One approach to FEL devices with large values of {eta} (in excess of 10 %) is to use a ``tapered`` (or nonuniform) wiggler. This approach was followed at several laboratories during the FEL development Program for the Strategic Defense Initiative (SDI) project. In this paper, we review some concepts and technical requirements for high-power tapered-wiggler FELs driven by radio-frequency linear accelerators (rf-linacs) which were developed during the SDI project. Contributions from three quite different technologies - rf-accelerators, optics, and magnets - are needed to construct and operate an FEL oscillator. The particular requirements on these technologies for a high-power FEL were far beyond the state of the art in those areas when the SDI project started, so significant advances had to be made before a working device could be constructed. Many of those requirements were not clearly understood when the project started, but were developed during the course of the experimental and theoretical research for the project. This information can be useful in planning future high-power FEL projects.

  12. Simulation of free-electron lasers seeded with broadband radiation

    SciTech Connect

    Bajlekov, Svetoslav; Fawley, William; Schroeder, Carl; Bartolini, Riccardo; Hooker, Simon

    2011-03-10

    The longitudinal coherence of free-electron laser (FEL) radiation can be enhanced by seeding the FEL with high harmonics of an optical laser pulse. The radiation produced by high-harmonic generation (HHG), however, has a fast-varying temporal profile that can violate the slowly varying envelope approximation and limited frequency window that is employed in conventional free-electron laser simulation codes. Here we investigate the implications of violating this approximation on the accuracy of simulations. On the basis of both analytical considerations and 1D numerical studies, it is concluded that, for most realistic scenarios, conventional FEL codes are capable of accurately simulating the FEL process even when the seed radiation violates the slowly varying envelope approximation. We additionally discuss the significance of filtering the harmonic content of broadband HHG seeds.

  13. Free-electron lasers driven by laser plasma accelerators

    NASA Astrophysics Data System (ADS)

    van Tilborg, J.; Barber, S. K.; Isono, F.; Schroeder, C. B.; Esarey, E.; Leemans, W. P.

    2017-03-01

    Laser-plasma accelerators (LPAs) have the potential to drive compact free-electron lasers (FELs). Even with LPA energy spreads typically at the percent level, the e-beam brightness can be excellent, due to the low normalized emittance (<0.5 µm) and high peak current (multi-kA) resulting from the ultra-short e-beam duration (few fs). It is critical, however, that in order to mitigate the effect of percent-level energy spread, one has to actively manipulate the phase-space distribution of the e-beam. We provide an overview of the methods proposed by the various LPA FEL research groups. At the BELLA Center at LBNL, we are pursuing the use of a chicane for longitudinal e-beam decompression (therefore greatly reducing the slice energy spread), in combination with short-scale-length e-beam transportation with an active plasma lens and a strong-focusing 4-m-long undulator. We present ELEGANT & GENESIS simulations on the transport and FEL gain, showing strong enhancement in output power over the incoherent background, and present estimates of the 3D gain length for deviations from the expected e-beam properties (varying e-beam lengths and emittances). To highlight the role of collective effects, we also present ELEGANT & GENESIS simulation results.

  14. Thermal effect control for biomedical tissue by free electron laser

    NASA Astrophysics Data System (ADS)

    Yoshihashi-Suzuki, Sachiko; Kanai, Taizo; Awazu, Kunio

    2007-02-01

    An absorption characteristic and a thermal relaxation time of a target biomedical tissue is an important parameter for development of low-invasive treatment that considers of interaction between biomedical tissue and laser. Laser irradiations with a wavelength corresponding to the absorption characteristics of tissue enable selective treatment. Furthermore, the thermal effect to tissue can be controlled at the laser irradiation time which depends on the laser pulse width and reception rate. A free electron laser (FEL) can continuously vary the wavelength in the mid-infrared region, has a unique pulse structure; the structure at the Institute of the Free Electron Laser (iFEL) consist of train of macropulses with a 15 μs pulse width, and each macropulse contained a train of 300-400 ultrashort micropulse with a 5 ps pulse width. In a previous report, we have proposed a novel laser treatment such as soft tissue cutting, dental treatment and laser angioplasty using the tenability of the FEL. To investigate the thermal effect to the biomedical tissue, we developed a FEL pulse control system using an acousto-optic modulator (AOM). The AOM commonly are used the Q-switch for the pulse laser generation, has a high pulse control efficiency and good operationally. The system can control the FEL macropulse width from 200 ns. This system should be a novel tool for investigating the interaction between the FEL and biomedical tissue. In this report, the interaction between FEL pulse width and biomedical tissue will be discussed.

  15. Induction linac driven free-electron lasers for microwave generation

    NASA Astrophysics Data System (ADS)

    Barletta, William A.

    1992-03-01

    The recent development of highly reliable components for linear induction accelerators (LIA) and free-electron lasers (FEL) enable one to use these devices as economical sources of microwave power to drive magnetic fusion reactors and high gradient, rf linear accelerators. Based on the specifications and costs of the recently designed and fabricated LIA components at the Lawrence Livermore National Laboratory, Science Research Laboratory, Inc., and Pulse Sciences, Inc., this paper reviews the present technology of linear induction accelerators and presents an algorithm for scaling the cost of LIA-driven microwave sources to the high average power regime of interest for the next generation of fusion research machines and linear electorn-positron colliders at TeV energies. The algorithm allows one to optimize the output power of the sources with respect to cost (or other figure of merit) by varying he characteristics (pulse length, driven current, repetition rate, etc.) of the linear induction accelerator. It also allows one to explore cost sensitivities as a guide to formulating research strategies for developing advanced accelerator technologies.

  16. Chirped pulse inverse free-electron laser vacuum accelerator

    DOEpatents

    Hartemann, Frederic V.; Baldis, Hector A.; Landahl, Eric C.

    2002-01-01

    A chirped pulse inverse free-electron laser (IFEL) vacuum accelerator for high gradient laser acceleration in vacuum. By the use of an ultrashort (femtosecond), ultrahigh intensity chirped laser pulse both the IFEL interaction bandwidth and accelerating gradient are increased, thus yielding large gains in a compact system. In addition, the IFEL resonance condition can be maintained throughout the interaction region by using a chirped drive laser wave. In addition, diffraction can be alleviated by taking advantage of the laser optical bandwidth with negative dispersion focusing optics to produce a chromatic line focus. The combination of these features results in a compact, efficient vacuum laser accelerator which finds many applications including high energy physics, compact table-top laser accelerator for medical imaging and therapy, material science, and basic physics.

  17. The multi-cavity free-electron laser

    SciTech Connect

    Krishnagopal, S.; Rangarajan, G.; Sessler, A.

    1992-07-01

    Consideration is made of a free-electron laser with many optical cavities where the cavities communicate with each other, not optically, but through the electron beam. Analysis is made in Ole one-dimensional approximation. A general expression is given for the growth rate in the exponential (high current) regime. In the regime where lethargy is important expressions are given in the two opposite limits of small and large numbers of cavities and bunches. Numerical simulation results, still in the one-dimensional approximation, but including non-linearities, are presented. The multi-cavity free-electron laser (MC/FEL) can be employed to avoid the slippage phenomena, and thus to make picosecond pulses of infra-red radiation. Three examples of this application are presented.

  18. Free-electron laser system with Raman amplifier outcoupling

    SciTech Connect

    Linford, G.J.

    1988-05-03

    A free-electron laser system is described comprising: a free-electron laser pump beam generator producing a high-power optical output beam in a vacuum environement; a Raman amplifier cell located in the path of the output beam from the pump beam generator; means for generating and introducing a Stokes seed beam into the Raman amplifier cell, a pair of gaseous windows through which the output beam enters and leaves the Raman amplifier cell, each window having a stream of gas moving continuously in a direction generally perpendicular to the beam; and a mirror positioned in the path of the output beam from the Raman amplifier, the mirror functioning to reflect and further direct the output beam, but not the unwanted spectral components.

  19. Crystallographic data processing for free-electron laser sources

    SciTech Connect

    White, Thomas A. Barty, Anton; Stellato, Francesco; Holton, James M.; Kirian, Richard A.; Zatsepin, Nadia A.; Chapman, Henry N.

    2013-07-01

    A processing pipeline for diffraction data acquired using the ‘serial crystallography’ methodology with a free-electron laser source is described with reference to the crystallographic analysis suite CrystFEL and the pre-processing program Cheetah. A processing pipeline for diffraction data acquired using the ‘serial crystallography’ methodology with a free-electron laser source is described with reference to the crystallographic analysis suite CrystFEL and the pre-processing program Cheetah. A detailed analysis of the nature and impact of indexing ambiguities is presented. Simulations of the Monte Carlo integration scheme, which accounts for the partially recorded nature of the diffraction intensities, are presented and show that the integration of partial reflections could be made to converge more quickly if the bandwidth of the X-rays were to be increased by a small amount or if a slight convergence angle were introduced into the incident beam.

  20. The multi-cavity free-electron laser

    NASA Astrophysics Data System (ADS)

    Krishnagopal, S.; Rangarajan, G.; Sessler, A.

    1992-07-01

    Consideration is made of a free-electron laser with many optical cavities where the cavities communicate with each other, not optically, but through the electron beam. Analysis is made in the one-dimensional approximation. A general expression is given for the growth rate in the exponential (high current) regime. In the regime where lethargy is important, expressions are given in the two opposite limits of small and large numbers of cavities and bunches. Numerical simulation results, still in the one-dimensional approximation, but including non-linearities, are presented. The multi-cavity free-electron laser (MC/FEL) can be employed to avoid the slippage phenomena, and thus to make picosecond pulses of infra-red radiation. Three examples of this application are presented.

  1. Fifth-Generation Free-Electron Laser Light Sources

    SciTech Connect

    Pellegrini, Claudio

    2011-03-02

    During the past few years, the Linac Coherent Light Source (LCLS) and the Free-Electron Laser in Hamburg (FLASH) have demonstrated the outstanding capability of free-electron lasers (FELs) as sources of coherent radiation in the soft and hard x-ray region. The high intensity, tens of GW, short pulses (few to less than 100 femtoseconds, and the unique transverse coherence properties are opening a new window to study the structure and dynamics of atomic and molecular systems. The LCLS, FLASH, and the other FELs now under construction are only the beginning of the development of these light sources. The next generations will reach new levels of performance: terawatt, atto-second, ultra-small line-width, high repetition rate, full longitudinal and transverse coherence. These future developments and the R&D needed to successfully build and operate the next generation of FEL light sources will be discussed.

  2. Multi-dimensional free-electron laser simulation codes : a comparison study.

    SciTech Connect

    Biedron, S. G.; Chae, Y. C.; Dejus, R. J.; Faatz, B.; Freund, H. P.; Milton, S. V.; Nuhn, H.-D.; Reiche, S.

    1999-08-23

    A self-amplified spontaneous emission (SASE) free-electron laser (FEL) is under construction at the Advanced Photon Source (APS). Five FEL simulation codes were used in the design phase: GENESIS, GINGER, MEDUSA, RON, and TDA3D. Initial comparisons between each of these independent formulations show good agreement for the parameters of the APS SASE FEL.

  3. Multi-dimensional free-electron laser simulation codes: a comparison study

    NASA Astrophysics Data System (ADS)

    Biedron, S. G.; Chae, Y. C.; Dejus, R. J.; Faatz, B.; Freund, H. P.; Milton, S. V.; Nuhn, H.-D.; Reiche, S.

    2000-05-01

    A self-amplified spontaneous emission (SASE) free-electron laser (FEL) is under construction at the Advanced Photon Source (APS). Five FEL simulation codes were used in the design phase: GENESIS, GINGER, MEDUSA, RON, and TDA3D. Initial comparisons between each of these independent formulations show good agreement for the parameters of the APS SASE FEL.

  4. Multi-Dimensional Free-Electron Laser Simulation Codes: A Comparison Study

    SciTech Connect

    Nuhn, Heinz-Dieter

    2003-04-28

    A self-amplified spontaneous emission (SASE) free-electron laser (FEL) is under construction at the Advanced Photon Source (APS). Five FEL simulation codes were used in the design phase: GENESIS, GINGER, MEDUSA, RON, and TDA3D. Initial comparisons between each of these independent formulations show good agreement for the parameters of the APS SASE FEL.

  5. Higher-Order Modes in Free Electron Lasers

    DTIC Science & Technology

    2005-09-01

    NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS Higher -Order Modes in Free Electron Lasers by B. W. Williams September 2005 Thesis Advisor: W...AGENCY USE ONLY (Leave blank) 2. REPORT DATE September 2005 3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE: Higher ...for the fundamental Gaussian mode, and higher -order modes in Cartesian and cylindrical coordinate spaces, yielding expressions for the complete and

  6. Quantum/classical mode evolution in free electron laser oscillators

    NASA Technical Reports Server (NTRS)

    Bosco, P.; Colson, W. B.; Freedman, R. A.

    1983-01-01

    The problem of oscillator evolution and mode competition in free electron lasers is studied. Relativistic quantum field theory is used to calculate electron wave functions, the angular distribution of spontaneous emission, and the transition rates for stimulated emission and absorption in each mode. The photon rate equation for the weakfield regime is presented. This rate equation is applied to oscillator evolution with a conventional undulator, a two-stage optical klystron, and a tapered undulator. The effects of noise are briefly discussed.

  7. Free-electron laser simulations on the MPP

    NASA Technical Reports Server (NTRS)

    Vonlaven, Scott A.; Liebrock, Lorie M.

    1987-01-01

    Free electron lasers (FELs) are of interest because they provide high power, high efficiency, and broad tunability. FEL simulations can make efficient use of computers of the Massively Parallel Processor (MPP) class because most of the processing consists of applying a simple equation to a set of identical particles. A test version of the KMS Fusion FEL simulation, which resides mainly in the MPPs host computer and only partially in the MPP, has run successfully.

  8. A 3-dimensional theory of free electron lasers

    SciTech Connect

    Webb, S.D.; Wang, G.; Litvinenko, V.N.

    2010-08-23

    In this paper, we present an analytical three-dimensional theory of free electron lasers. Under several assumptions, we arrive at an integral equation similar to earlier work carried out by Ching, Kim and Xie, but using a formulation better suited for the initial value problem of Coherent Electron Cooling. We use this model in later papers to obtain analytical results for gain guiding, as well as to develop a complete model of Coherent Electron Cooling.

  9. Quantum/classical mode evolution in free electron laser oscillators

    NASA Technical Reports Server (NTRS)

    Bosco, P.; Colson, W. B.; Freedman, R. A.

    1983-01-01

    The problem of oscillator evolution and mode competition in free electron lasers is studied. Relativistic quantum field theory is used to calculate electron wave functions, the angular distribution of spontaneous emission, and the transition rates for stimulated emission and absorption in each mode. The photon rate equation for the weakfield regime is presented. This rate equation is applied to oscillator evolution with a conventional undulator, a two-stage optical klystron, and a tapered undulator. The effects of noise are briefly discussed.

  10. Free electron laser based on the Smith Purcell radiation

    NASA Astrophysics Data System (ADS)

    Wang, Minghong; Liu, Pukun; Ge, Guangying; Dong, Ruixin

    2007-09-01

    A Smith-Purcell (S-P) free electron laser (FEL) composed of a metallic diffraction flat grating, an open cylindrical mirror cavity and a relativistic sheet electron beam with moderate energy, is presented. The characteristics of this device are studied by theoretical analysis, experimental measurements and particle-in-cell (PIC) simulation method. Results indicate that coherent radiation with output peak power up to 50 MW at millimeter wavelengths can be generated by using relativistic electron beam of moderate energy.

  11. Free electron laser based on the Smith — Purcell radiation

    NASA Astrophysics Data System (ADS)

    Wang, Ming-Hong; Xiao, Xiao-Guang; Yu, Hui-Shan; Meng, Xian-Zhu

    2006-11-01

    A Smith-Purcell (SP) free electron laser (FEL), composed of a metallic diffraction flat grating, an open cylindrical mirror cavity and a relativistic sheet electron beam with moderate energy, is presented. The characteristics of this device are studied by theoretical analysis, experimental measurements and particle-in-cell (PIC) simulation method. Results indicate that the coherent radiation with an output peak power up to 50 MW at millimeter wavelengths can be generated by using relativistic electron beam of moderate energy

  12. Study on a novel Smith Purcell free-electron laser

    NASA Astrophysics Data System (ADS)

    Wang, Minghong; Xiao, Xiaoguang; Chen, Jiayu; Wei, Yanyu

    2005-10-01

    A novel Smith Purcell (SP) free-electron laser (FEL) with axial-symmetrical structure is proposed. The distribution of the high frequency field in the resonator is analyzed and the operating frequency and output power are also studied by the use of particle-in-cell (PIC) simulation method. Results indicate that coherent radiation with output peak power up to 58 MW at millimeter wavelengths can be generated by using relativistic electron beams of moderate energy.

  13. Spreader Design for FERMI@Elettra Free Electron Laser

    SciTech Connect

    Zholents, A.; Bacescu, D.; Chow, K.; Diviacco, B.; Ferianis, M.; Di Mitri, S.; Wells, R.

    2007-01-18

    In this note we describe a conceptual design of a part ofthe electron beam delivery system for FERMI@Elettra free electron laser(FEL) located between the end of the linac and the entrance to the FEL.This part includes the emittance diagnostic section, the electron beamswitchyard for two FELs called spreader and matching sections. The designmeets various constrains imposed by the existing and planned buildingboundaries, desire for utilization of existing equipment and demands forvarious diagnostic instruments.

  14. An Efficient Microwave Power Source: Free-electron Laser Afterburner

    SciTech Connect

    Wang, C.; Sessler, Andrew M.

    1993-03-04

    A kind of microwave power source, called a free-electron laser afterburner (FEL afterburner) which consists of a free-electron laser buncher and a slow-wave output structure sharing a magnetic wiggler field with the buncher, is proposed. The buncher and the slow-wave structure can operate in either a travelling-wave state or a standing-wave state. In the buncher, the wiggler field together with the radiation field makes an electron beam bunched, and in the slow-wave structure the wiggler field keeps the beam bunched while the bunched beam interacts strongly with the slow-wave structure and so produces rf power. The bunching process comes from the free-electron laser mechanism and the generating process of rf power is in a slow-wave structure. A three-dimensional, time-dependent code is used to simulate a particular standing-wave FEL afterburner and it is shown that rf power of up to 1.57 GW can be obtained, at 17.12 GHz, from a l-kA, 5-MeV electron beam.

  15. Demonstration of cascaded optical inverse free-electron laser accelerator.

    PubMed

    Dunning, M; Hemsing, E; Hast, C; Raubenheimer, T O; Weathersby, S; Xiang, D; Fu, F

    2013-06-14

    We report on a proof-of-principle demonstration of a two-stage cascaded optical inverse free-electron laser (IFEL) accelerator in which an electron beam is accelerated by a strong laser pulse after being packed into optical microbunches by a weaker initial laser pulse. We show experimentally that injection of precisely prepared optical microbunches into an IFEL allows net acceleration or deceleration of the beam, depending on the relative phase of the two laser pulses. The experimental results are in excellent agreement with simulation. The demonstrated technique holds great promise to significantly improve the beam quality of IFELs and may have a strong impact on emerging laser accelerators driven by high-power optical lasers.

  16. Demonstration of Cascaded Optical Inverse Free-Electron Laser Accelerator

    NASA Astrophysics Data System (ADS)

    Dunning, M.; Hemsing, E.; Hast, C.; Raubenheimer, T. O.; Weathersby, S.; Xiang, D.; Fu, F.

    2013-06-01

    We report on a proof-of-principle demonstration of a two-stage cascaded optical inverse free-electron laser (IFEL) accelerator in which an electron beam is accelerated by a strong laser pulse after being packed into optical microbunches by a weaker initial laser pulse. We show experimentally that injection of precisely prepared optical microbunches into an IFEL allows net acceleration or deceleration of the beam, depending on the relative phase of the two laser pulses. The experimental results are in excellent agreement with simulation. The demonstrated technique holds great promise to significantly improve the beam quality of IFELs and may have a strong impact on emerging laser accelerators driven by high-power optical lasers.

  17. Pulse Splitting in Short Wavelength Seeded Free Electron Lasers

    SciTech Connect

    Labat, M.; Couprie, M. E.; Joly, N.; Bruni, C.

    2009-12-31

    We investigate a fundamental limitation occurring in vacuum ultraviolet and extreme ultraviolet seeded free electron lasers (FELs). For a given electron beam and undulator configuration, an increase of the FEL output energy at saturation can be obtained via an increase of the seed pulse duration. We put in evidence a complex spatiotemporal deformation of the amplified pulse, leading ultimately to a pulse splitting effect. Numerical studies of the Colson-Bonifacio FEL equations reveal that slippage length and seed laser pulse wings are core ingredients of the dynamics.

  18. Aerosol Imaging with a Soft X-ray Free Electron Laser

    SciTech Connect

    Bogan, Michael J.; Boutet, Sebastien; Chapman, Henry N.; Marchesini, Stefano; Barty, Anton; Benner, W.Henry Rohner, Urs; Frank, Matthias; Hau-Riege, Stefan P.; Bajt, Sasa; Woods, Bruce; Seibert, M.M.; Iwan, Bianca; Timneanu, Nicusor; Hajdu, Janos; Schulz, Joachim; /DESY

    2011-08-22

    Lasers have long played a critical role in the advancement of aerosol science. A new regime of ultrafast laser technology has recently be realized, the world's first soft xray free electron laser. The Free electron LASer in Hamburg, FLASH, user facility produces a steady source of 10 femtosecond pulses of 7-32 nm x-rays with 10{sub 12} photons per pulse. The high brightness, short wavelength, and high repetition rate (>500 pulses per second) of this laser offers unique capabilities for aerosol characterization. Here we use FLASH to perform the highest resolution imaging of single PM2.5 aerosol particles in flight to date. We resolve to 35 nm the morphology of fibrous and aggregated spherical carbonaceous nanoparticles that existed for less than two milliseconds in vacuum. Our result opens the possibility for high spatialand time-resolved single particle aerosol dynamics studies, filling a critical technological need in aerosol science.

  19. Compact two-beam push-pull free electron laser

    DOEpatents

    Hutton, Andrew

    2009-03-03

    An ultra-compact free electron laser comprising a pair of opposed superconducting cavities that produce identical electron beams moving in opposite directions such that each set of superconducting cavities accelerates one electron beam and decelerates the other electron beam. Such an arrangement, allows the energy used to accelerate one beam to be recovered and used again to accelerate the second beam, thus, each electron beam is decelerated by a different structure than that which accelerated it so that energy exchange rather than recovery is achieved resulting in a more compact and highly efficient apparatus.

  20. Characteristics of the MIT microwiggler for free electron laser applications

    SciTech Connect

    Catravas, P.; Stoner, R.; Bekefi, G.

    1995-12-31

    We report work on the development of microwiggler technology for free electron laser research. The MIT microwiggler is a pulsed electromagnet with 70 periods of 8.8 mm each which generates a peak on-axis field of 4.2 kG. The wiggler is characterized by extensive tunability. We developed a novel tuning regimen to control 140 degrees of freedom afforded by the individually tunable half periods and achieved an rms spread in the peak amplitudes of 0.08%. This is the lowest attained to date in any sub-cm period wiggler. The microwiggler design and comprehensive measurements of its characteristics will be described.

  1. Two-Stage FEL (Free Electron Laser) Program.

    DTIC Science & Technology

    1983-08-25

    Sargent and Spitzer editors, Addison-Wesley (1982). 3. S. B . Segall, H. R. Hiddleston, H. Takeda, S. Von Laven, R. Holsinger, J. Ward , J. Richardson, and W...1983). 4. S. Von Laven, S. B . Segall, J. F. Ward , "A Low Loss Quasioptical Cavity for a Two-Stage Free Electron Laser", in the proceedings of this...CLASSIFICATION OF THIS PAGE Mhen Data Entered) _ _"_ _ _A READ IMMUCTIONS REPORT DOCUMENTATION PAGE B n oR ORM I. REPORT NUMER 2. GOVT ACCESSION NO

  2. Design Alternatives for a Free Electron Laser Facility

    SciTech Connect

    Jacobs, K; Bosch, R A; Eisert, D; Fisher, M V; Green, M A; Keil, R G; Kleman, K J; Kulpin, J G; Rogers, G C; Wehlitz, R; Chiang, T; Miller, T J; Lawler, J E; Yavuz, D; Legg, R A; York, R C

    2012-07-01

    The University of Wisconsin-Madison is continuing design efforts for a vacuum ultraviolet/X-ray Free Electron Laser facility. The design incorporates seeding the FEL to provide fully coherent photon output at energies up to {approx}1 keV. The focus of the present work is to minimize the cost of the facility while preserving its performance. To achieve this we are exploring variations in the electron beam driver for the FEL, in undulator design, and in the seeding mechanism. Design optimizations and trade-offs between the various technologies and how they affect the FEL scientific program will be presented.

  3. Deep saturated Free Electron Laser oscillators and frozen spikes

    NASA Astrophysics Data System (ADS)

    Ottaviani, P. L.; Pagnutti, S.; Dattoli, G.; Sabia, E.; Petrillo, V.; Slot, P. J. M. van der; Biedron, S.; Milton, S.

    2016-10-01

    We analyze the behavior of Free Electron Laser (FEL) oscillators operating in the deep saturated regime and point out the formation of sub-peaks of the optical pulse. These are very stable configurations and the sub-peaks are found to have a duration corresponding to the coherence length. We speculate on the physical mechanisms underlying their growth and attempt an identification with natural mode-locked structures in FEL oscillators. Their impact on the intra-cavity nonlinear harmonic generation is also discussed along with the possibility of exploiting them as cavity out-coupler.

  4. SIMPLEX: simulator and postprocessor for free-electron laser experiments

    PubMed Central

    Tanaka, Takashi

    2015-01-01

    SIMPLEX is a computer program developed for simulating the amplification process of free-electron lasers (FELs). It numerically solves the so-called FEL equations describing the evolution of the radiation field and growth of microbunching while the electron beam travels along the undulator. In order to reduce the numerical cost, the FEL equations have been reduced to more convenient forms for numerical implementation by applying reasonable approximations. SIMPLEX is equipped with a postprocessor to facilitate the retrieval of desired information from the simulation results, which is crucial for practical applications such as designing the beamline and analyzing the experimental results. PMID:26289287

  5. Small-period electromagnet wigglers for free-electron lasers

    SciTech Connect

    Granatstein, V.L.; Destler, W.W.; Mayergoyz, I.D.

    1985-09-15

    A new configuration for wiggler magnets compatible with free-electron laser (FEL) deployment is described and demonstrated experimentally. The configuration is simple and inexpensive to fabricate and allows for continuous control of magnetic field amplitude. Because ferromagnetic cores are used, the wiggler fields are strong (approx.0.1 T), while the wiggler period can be very small, on the order of 1 mm. It is shown that high power millimeter and submillimeter FEL's could be built using such wigglers together with sheet electron beams, and that they would have substantially reduced electron energy requirements when compared with FEL's employing larger period wigglers.

  6. Design Study of a Free Electron Laser Storage Ring,

    DTIC Science & Technology

    1980-06-01

    rAD-AU2 75TAFORD UNVCA7 HIGH ENERGY PHYSICS LAB F/G 20/5 DESIGN STUDY OF A FREE ELECTRON LASER STORAGE RING, (U)~jUN 80 H WIEOMANN UNCLASSIFIED HELT...particle to emit a high energy photon which causes a large pertdrbation of the betatron and synchro- tron oscillation. Calculations of this effect 1 show...in this storage ring design too. The most significant effect to limit the beam lifetime in low energy , high intensity storage rings is the so-called

  7. Higher harmonic inverse free-electron laser interaction.

    PubMed

    Musumeci, P; Pellegrini, C; Rosenzweig, J B

    2005-07-01

    We expand the theory of the inverse free electron laser (IFEL) interaction to include the possibility of energy exchange that takes place when relativistic particles traversing an undulator interact with an electromagnetic wave of a frequency that is a harmonic of the fundamental wiggler resonant frequency. We derive the coupling coefficients as a function of the IFEL parameters for all harmonics, both odd and even. The theory is supported by simulation results obtained with a three-dimensional Lorentz equation solver code. Comparisons are made between the results of theory and simulations, and the recent UCLA IFEL experimental results where higher harmonic IFEL interaction was observed.

  8. Higher harmonic inverse free-electron laser interaction

    NASA Astrophysics Data System (ADS)

    Musumeci, P.; Pellegrini, C.; Rosenzweig, J. B.

    2005-07-01

    We expand the theory of the inverse free electron laser (IFEL) interaction to include the possibility of energy exchange that takes place when relativistic particles traversing an undulator interact with an electromagnetic wave of a frequency that is a harmonic of the fundamental wiggler resonant frequency. We derive the coupling coefficients as a function of the IFEL parameters for all harmonics, both odd and even. The theory is supported by simulation results obtained with a three-dimensional Lorentz equation solver code. Comparisons are made between the results of theory and simulations, and the recent UCLA IFEL experimental results where higher harmonic IFEL interaction was observed.

  9. The LLNL/UCLA high gradient inverse free electron laser

    NASA Astrophysics Data System (ADS)

    Moody, J. T.; Musumeci, P.; Anderson, G.; Anderson, S.; Betts, S.; Fisher, S.; Gibson, D.; Tremaine, A.; Wu, S.

    2012-12-01

    We describe the Inverse Free Electron Accelerator currently under construction at Lawrence Livermore National Lab. Upon completion of this accelerator, high brightness electrons generated in the photoinjector blowout regime and accelerated to 50 MeV by S-band accelerating sections will interact with > 4 TW peak power Ti:Sapphire laser in a highly tapered 50 cm undulator and experience an acceleration gradient of > 200 MeV/m. We present the final design of the accelerator as well as the results of start-to-end simulations investigating preservation of beam quality and tolerances involved with this accelerator.

  10. SIMPLEX: simulator and postprocessor for free-electron laser experiments.

    PubMed

    Tanaka, Takashi

    2015-09-01

    SIMPLEX is a computer program developed for simulating the amplification process of free-electron lasers (FELs). It numerically solves the so-called FEL equations describing the evolution of the radiation field and growth of microbunching while the electron beam travels along the undulator. In order to reduce the numerical cost, the FEL equations have been reduced to more convenient forms for numerical implementation by applying reasonable approximations. SIMPLEX is equipped with a postprocessor to facilitate the retrieval of desired information from the simulation results, which is crucial for practical applications such as designing the beamline and analyzing the experimental results.

  11. Electron injector for Iranian Infrared Free Electron Laser

    NASA Astrophysics Data System (ADS)

    Rajabi, A.; Jazini, J.; Fathi, M.; Khosravi, N.; Shokri, B.

    2016-12-01

    The quality of the electron beam for applications like free electron lasers (FELs) has a direct impact on the quality of the laser radiation. The electron injector considered for Iranian Infrared Free Electron Laser (IRIFEL) includes a thermionic RF electron gun plus a bunch compressor as the electron preinjector and a 50 MeV constant gradient traveling wave linac as the main accelerator of the electron injector. In the present work, a thermionic RF gun is designed and matched with an optimized linac to produce a high quality mono-energetic electron beam. The results show that the preinjector is capable of delivering an electron bunch with 1 ps bunch length and 3 mm-mrad emittance to the linac entrance which is desirable for IRIFEL operation. The results also show that by geometrical manipulation and optimization of the linac structure, the pattern of the RF fields in the linac will be more symmetric, which is important in order to produce high stable mono-energetic bunches.

  12. Inverse Free Electron Laser Experiment at the Neptune Laboratory

    NASA Astrophysics Data System (ADS)

    Musumeci, P.; Pellegrini, C.; Rosenzweig, J. B.; Varfolomeev, A.; Tolmachev, S.; Yarovoi, T.

    2002-12-01

    We present an Inverse Free Electron Laser accelerator proposed for construction at the UCLA Neptune Laboratory. This experiment will use a 1 TW CO2 laser to accelerate through two strongly tapered undulators an electron beam from 16 MeV up to 55 MeV. The scheme proposed is the diffraction dominated IFEL interaction. The Raleigh range of the laser beam is about 2 cm, much shorter than the interaction length (the undulator length is 50 cm). In this regime adiabatic capture is possible in the first part of the undulator. In the focus region, we propose a solution to the problem of the dephasing between electrons and photons due to the Guoy phase shift. Ponderomotive effects and implications for tolerances are also studied.

  13. Beam conditioner for free electron lasers and synchrotrons

    DOEpatents

    Liu, H.; Neil, G.R.

    1998-09-08

    A focused optical has been used to introduce an optical pulse, or electromagnetic wave, collinear with the electron beam in a free electron laser or synchrotron thereby adding an axial field component that accelerates the electrons on the radial outside of the distribution of electrons in the electron beam. This invention consists of using the axial electrical component of a TEM{sub 10} mode Gaussian beam in vacuum to condition the electron beam and speed up the outer electrons in the beam. The conditioning beam should possess about the same diameter as the electron beam. The beam waist of the conditioning wave must be located around the entrance of the undulator longitudinally to have a net energy exchange between the electrons in the outer part of the distribution and the conditioning wave owing to the natural divergence of a Gaussian beam. By accelerating the outer electrons, the outer and core electrons are caused to stay in phase. This increases the fraction of the electron beam energy that is converted to light thereby improving the efficiency of conversion of energy to light and therefore boosting the power output of the free electron laser and synchrotron. 4 figs.

  14. Beam conditioner for free electron lasers and synchrotrons

    DOEpatents

    Liu, Hongxiu; Neil, George R.

    1998-01-01

    A focused optical is been used to introduce an optical pulse, or electromagnetic wave, colinearly with the electron beam in a free electron laser or synchrotron thereby adding an axial field component that accelerates the electrons on the radial outside of the distribution of electrons in the electron beam. This invention consists of using the axial electrical component of a TEM.sub.10 mode Gaussian beam in vacuum to condition the electron beam and speed up the outer electrons in the beam. The conditioning beam should possess about the same diameter as the electron beam. The beam waist of the conditioning wave must be located around the entrance of the undulator longitudinally to have a net energy exchange between the electrons in the outer part of the distribution and the conditioning wave owing to the natural divergence of a Gaussian beam. By accelerating the outer electrons, the outer and core electrons are caused to stay in phase. This increases the fraction of the electron beam energy that is converted to light thereby improving the efficiency of conversion of energy to light and therefore boosting the power output of the free electron laser and synchrotron.

  15. The European XFEL Free Electron Laser at DESY

    ScienceCinema

    Weise, Hans [Deutsches Elektronen-Synchrotron, Germany

    2016-07-12

    The European X-ray Free-Electron laser Facility (XFEL) is going to be built in an international collaboration at the Deutsches Elektronen-Synchrotron (DESY), Germany, and the Technical Design Report was published in 2006. The official project is expected for summer 2007. This new facility will offer photon beams at wavelengths as short as 1 angstrom with highest peak brilliance being more than 100 million times higher than present day synchrotron radiation sources. The radiation has a high degree of transverse coherence and the pulse duration is reduced from {approx}100 picoseconds (typ. for SR light sources) down to the {approx}10 femtosecond time domain. The overall layout of the XFEL will be described. This includes the envisaged operation parameters for the linear accelerator using superconducting TESLA technology. The complete design is based on the actually operated FLASH free-electron laser at DESY. Experience with the operation during first long user runs at wavelengths from 30 to 13 nm will be described in detail.

  16. A new beam source for free electron lasers

    SciTech Connect

    Wang, M.C.; Wang, Z.J.; Zhu, J.B.

    1995-12-31

    A high power, high current density and high voltage electron beam was generated with the pseudospark discharge (PS), this is a new beam source for free electron lasers. The design and construction of the pseudospark discharge was described, the device has low cost and is easy to fabricate. The experiments are presented, the configuration parameters of the modified pulse line accelerator (PLA) are as follows. The PS hollow cavity has a 3 cm diameter and 4.1 cm long. The discharge chamber consists of planar cathode with hollow cavity, sets of intermediate electrodes and insulators with a common channel, and a planar anode. The electrodes are made of brass and the insulators are made of Plexiglas. The diameter of the channel is 3.2 mm. The anode-cathode gap distance is varied in 10-100 mm. The electron beams have voltage of 200 KeV, current of 2 KA and beam diameter of 1mm. The beam penetrated a 0.3 mm hole on a copper foil of 0.05 mm thick at the distance of 5 cm from the anode and penetrated a 0.6 mm hole on an acid-sensitive film at the distance of 15 cm. A compact free electron laser with a table size is discussed.

  17. Numerical simulation of Smith-Purcell free-electron lasers.

    SciTech Connect

    Kumar, V.; Kim, K.-J.; Accelerator Systems Division

    2005-01-01

    We present a one-dimensional time-dependent analysis and simulation of Smith-Purcell (SP) free-electron lasers (FELs). The coupled Maxwell-Lorentz equations are set up, and the details of numerical simulation are presented. At low electron beam energy, a SP-FEL is a backward wave oscillator (BWO), and oscillations can be achieved without the need for feedback mirrors. In the linear regime, we show that the optical power grows exponentially if the current is larger than a certain value, the start current. Results of our numerical calculation compare well with the analytic calculation in the linear regime and show saturation behavior in the nonlinear regime. An electron beam traveling close and parallel to a mettalic grating, with grating rulings perpendicular to the electron motion, gives off polarized electromagnetic radiation known as Smith-Purcell radiation. A Smith-Purcell free-electron laser (SP-FEL) based on this effect is interesting as a possible compact source of tunable, coherent THz radiation. Analytic theory of SP-FELs in the linear regime has been discussed by several authors under different approximations. Here, we present a fully self-consistent nonlinear analysis, which can be used to understand the saturation behavior and simulate the realistic effects; coupled Maxwell-Lorentz equations for an SP-FEL driven by sheet beam are derived and solved numerically to perform detailed analysis.

  18. Free-electron laser as a laboratory instrument

    SciTech Connect

    Schmerge, J.F.; Lewellen, J.W.; Huang, Y.C.; Feinstein, J.; Pantell, R.H.

    1995-06-01

    A free-electron laser (FEL), with a component cost, including the accelerator, of approximately $300,000, has a laser at a wavelength of 85 microns with approx. 12 ps micropulse duration, achieving a power growth four orders of magnitude greater than the coherent spontaneous emission, and with a small-signal, single-pass gain of 21%. The price is about an order of magnitude less than other FELs for the far infrared, and transforms the device from the role of a national facility to that of a laboratory instrument. Cost reduction was achieved by employing several novel features: a microwave cavity gun for the accelerator, a staggered-array wiggler, and an on-axis hole in the upstream cavity mirror for electron ingress and radiation egress.

  19. X-Ray Free Electron Laser Interaction With Matter

    SciTech Connect

    Hau-Riege, S

    2009-05-12

    X-ray free electron lasers (XFELs) will enable studying new areas of laser-matter interaction. We summarize the current understanding of the interaction of XFEL pulses with matter and describe some of the simulation approaches that are used to design experiments on future XFEL sources. Modified versions of these models have been successful in guiding and analyzing experiments performed at the extreme-ultraviolet FEL FLASH at wavelengths of 6 nm and longer. For photon energies of several keV, no XFEL-matter interaction experiments have been performed yet but data is anticipated to become available in the near future, which will allow to test our understanding of the interaction physics in this wavelength regime.

  20. Beam Conditioning and Harmonic Generation in Free ElectronLasers

    SciTech Connect

    Charman, A.E.; Penn, G.; Wolski, A.; Wurtele, J.S.

    2004-07-05

    The next generation of large-scale free-electron lasers (FELs) such as Euro-XFEL and LCLS are to be devices which produce coherent X-rays using Self-Amplified Spontaneous Emission (SASE). The performance of these devices is limited by the spread in longitudinal velocities of the beam. In the case where this spread arises primarily from large transverse oscillation amplitudes, beam conditioning can significantly enhance FEL performance. Future X-ray sources may also exploit harmonic generation starting from laser-seeded modulation. Preliminary analysis of such devices is discussed, based on a novel trial-function/variational-principle approach, which shows good agreement with more lengthy numerical simulations.

  1. The stability of free-electron lasers against filamentation

    SciTech Connect

    Barnard, J.J.; Scharlemann, E.T.; Yu, S.S.

    1987-09-15

    In inertial confinement fusion (ICF) experiments, the high electromagnetic fields propagating through a relatively dense plasma can result in a transverse instability, causing the matter and light to form filaments oriented parallel to the light beam. We examine whether a similar instability exists in the electron beam of a free-electron laser, where such an instability could interfere with the transfer of beam kinetic energy into optical wave energy. We heuristically examine the instability in a relativistic beam through which an intense laser beam is propagating. We ignore the FEL effects. We estimate how the altered index of refraction in an FEL affects the dispersion relation. Finally, we estimate the effect that the instability could have on the phase coherence of a particle as it transits an FEL. 10 refs., 2 tabs.

  2. Multidimensional simulations of the ELFA superradiant free electron laser

    NASA Astrophysics Data System (ADS)

    Pierini, P.; Fawley, W. M.; Sharp, W. M.

    1991-07-01

    ELFA (electron laser facility for acceleration) is a high-gain, microwave ( ν = 100 GHz) free electron laser (FEL) facility driven by an rf linac. ELFA will test the existence of the theoretically predicted regimes of strong and weak superradiance. Both regimes can be studied with the same FEL by changing the height of the interaction waveguide, which controls the radiation group velocity, and thus the relative slippage between electrons and photons. The operation of ELFA has been modeled using a modified version of the two-dimensional, time-dependent sideband code GINGER. The simulations take into account the time and space variations of the radiation field, as well as the space charge and transverse emittance of the electron beam. The sensitivity of the superradiant signal to variations of the beam emittance, energy and energy spread is examined.

  3. Medical free-electron laser: fact or fiction?

    NASA Astrophysics Data System (ADS)

    Bell, James P.; Ponikvar, Donald R.

    1994-07-01

    The free electron laser (FEL) has long been proposed as a flexible tool for a variety of medical applications, and yet the FEL has not seen widespread acceptance in the medical community. The issues have been the laser's size, cost, and complexity. Unfortunately, research on applications of FELs has outpaced the device development efforts. This paper describes the characteristics of the FEL, as they have been demonstrated in the U.S. Army's FEL technology development program, and identifies specific medical applications where demonstrated performance levels would suffice. This includes new photodynamic therapies for cancer and HIV treatment, orthopedic applications, tissue welding applications, and multiwavelength surgical techniques. A new tunable kilowatt class FEL device is described, which utilizes existing hardware from the U.S. Army program. An assessment of the future potential, based on realistic technology scaling is provided.

  4. Long-base free electron laser resonant cavity

    SciTech Connect

    Miller, E.L.; Bender, S.C.; Appert, Q.D.; Saxman, A.C.; Swann, T.A.

    1985-01-01

    A 65-meter resonant cavity has been constructed in order to experimentally determine the characteristics of long resonant cavities as would be required for a free electron laser (FEL). A version using normal incidence mirrors is reported here, and another that includes a grazing incidence mirror is forthcoming. Either version is designed to simulate a FEL operating at 0.5 micron wavelength and is near-concentric with a stability parameter of 0.98. Argon-ion plasma tubes simulate the laser gain that would be provided by a wiggler in an actual FEL. The cavity was constructed on a seismic slab and air turbulence effects were reduced by surrounding the beam with helium in 6 in. diameter tubes. Alignment sensitivities are reported and compared to geometrical and diffraction predictions with good agreement.

  5. Free electron lasers as ground based space weapons

    NASA Astrophysics Data System (ADS)

    Goldstein, Gary R.

    1988-12-01

    The free electron laser (FEL) is the most promising directed energy weapon in the SDI program. Its theoretical underpinnings, present achievements and future prospects are reviewed. The general requirements of a ground based laser system are derived and are seen to be quite expensive to implement as well as being far beyond current technical capabilities. Atmospheric propagation effects, particularly Stimulated Raman Scattering, will make the transmission of adequate powers dubious. A summary of existing and proposed FEL parameters shows that, at best, future facilities will be many orders of magnitude away from the required GigaWatt average output powers in the visible or near infrared region. Prospects for FEL midcourse or terminal phase weapons are equally problematic, given the simple countermeasures available to the offense. Use as an ASAT weapon is less technically demanding, but of limited applicability given the vulnerability of an extensive space based targeting system.

  6. Acoustic analog of a free-electron laser

    SciTech Connect

    Zavtrak, S.T.

    1995-12-31

    As well known, at the present time there are many types of laser the operation of which is based on the stimulated emission of light by an active medium. Lasers are generators of coherent electromagnetic waves in the range from ultraviolet to submillimeters. But acoustic analogs of such devices have not been created up to now in spite of the progress in laser technology. Meanwhile, an acoustic laser could have a lot of interesting applications. Recently a theoretical scheme for an acoustic laser was proposed by the present author. A liquid dielectric with dispersed particles was considered as an active medium. The pumping was created by an oscillating electric field deforming dispersed particle volumes. Different types of oils or distilled water can serve as a liquid dielectric with gas bubbles as dispersed particles. Gas bubbles in water can be created by an electrolysis. The phase bunching of the initially incoherent emitters (gas bubbles) was realized by acoustic radiation forces. This scheme is an analog of the free-electron laser (FEL). It was shown that two types of losses must be overcome for the beginning of a generation. The first type results from the energy dissipation in the active medium and the second one is caused by radiation losses at the boundaries of the resonator. The purposes of this report are: (1) to discuss the analogies between the acoustic laser and FEL; (2) to propose an effective scheme of an acoustic laser with a mechanical pumping (by a piezoelectric emitter of the piston type); (3) to consider the schemes of acoustic lasers with the different types of the resonators (rectangular and cylindrical); (4) to discuss the possibility of the creation of an impact acoustic laser (5) to discuss the experimental works which are planned to be carried out in cooperation with prof. L.A. Crum.

  7. European X-Ray Free Electron Laser (EXFEL): local implications

    NASA Astrophysics Data System (ADS)

    Romaniuk, Ryszard S.

    2013-10-01

    European X-Ray FEL - free electron laser is under construction in DESY Hamburg. It is scheduled to be operational at 2015/16 at a cost more than 1 billion Euro. The laser uses SASE method to generate x-ray light. It is propelled by an electron linac of 17,5GeV energy and more than 2km in length. The linac uses superconducting SRF TESLA technology working at 1,3 GHz in frequency. The prototype of EXFEL is FLASH Laser (200 m in length), where the "proof of principle" was checked, and from the technologies were transferred to the bigger machine. The project was stared in the nineties by building a TTF Laboratory -Tesla Test Facility. The EXFEL laser is a child of a much bigger teraelectronovolt collider project TESLA (now abandoned in Germany but undertaken by international community in a form the ILC). A number of experts and young researchers from Poland participate in the design, construction and research of the FLASH and EXFEL lasers.

  8. Free electron lasers for transmission of energy in space

    NASA Technical Reports Server (NTRS)

    Segall, S. B.; Hiddleston, H. R.; Catella, G. C.

    1981-01-01

    A one-dimensional resonant-particle model of a free electron laser (FEL) is used to calculate laser gain and conversion efficiency of electron energy to photon energy. The optical beam profile for a resonant optical cavity is included in the model as an axial variation of laser intensity. The electron beam profile is matched to the optical beam profile and modeled as an axial variation of current density. Effective energy spread due to beam emittance is included. Accelerators appropriate for a space-based FEL oscillator are reviewed. Constraints on the concentric optical resonator and on systems required for space operation are described. An example is given of a space-based FEL that would produce 1.7 MW of average output power at 0.5 micrometer wavelength with over 50% conversion efficiency of electrical energy to laser energy. It would utilize a 10 m-long amplifier centered in a 200 m-long optical cavity. A 3-amp, 65 meV electrostatic accelerator would provide the electron beam and recover the beam after it passes through the amplifier. Three to five shuttle flights would be needed to place the laser in orbit.

  9. Theory and Simulation of an Inverse Free Electron Laser Experiment

    NASA Astrophysics Data System (ADS)

    Guo, S. K.; Bhattacharjee, A.; Fang, J. M.; Marshall, T. C.

    1996-11-01

    An experimental demonstration of the acceleration of electrons using a high power CO2 laser in an inverse free electron laser (IFEL) is underway at the Brookhaven National Laboratory. This experiment has generated data, which we are attempting to simulate. Included in our studies are such effects as: a low-loss metallic waveguide with a dielectric coating on the walls; multi-mode coupling due to self-consistent interaction between the electrons and the optical wave; space charge (which is significant at lower laser power); energy-spread of the electrons; arbitrary wiggler field profile; and slippage. Two types of wiggler profile have been considered: a linear taper of the period, and a step-taper of the period (the period is ~ 3cm, the field is ~ 1T, and the wiggler length is 47cm). The energy increment of the electrons ( ~ 1-2%) is analyzed in detail as a function of laser power, wiggler parameters, and the initial beam energy (40MeV). For laser power ~ 0.5GW, the predictions of the simulations are in good accord with experimental results. A matter currently under study is the discrepancy between theory and observations for the electron energy distribution observed at the end of the IFEL. This work is supported by the Department of Energy.

  10. Free-electron laser emission architecture impact on EUV lithography

    NASA Astrophysics Data System (ADS)

    Hosler, Erik R.; Wood, Obert R.; Barletta, William A.

    2017-03-01

    Laser-produced plasma (LPP) EUV sources have demonstrated approximately 125 W at customer sites, establishing confidence in EUV lithography as a viable manufacturing technology. However, beyond the 7 nm technology node existing scanner/source technology must enable higher-NA imaging systems (requiring increased resist dose and providing half-field exposures) and/or EUV multi-patterning (requiring increased wafer throughput proportional to the number of exposure passes. Both development paths will require a substantial increase in EUV source power to maintain the economic viability of the technology, creating an opportunity for free-electron laser (FEL) EUV sources. FEL-based EUV sources offer an economic, high-power/single-source alternative to LPP EUV sources. Should free-electron lasers become the preferred next generation EUV source, the choice of FEL emission architecture will greatly affect its operational stability and overall capability. A near-term industrialized FEL is expected to utilize one of the following three existing emission architectures: (1) selfamplified spontaneous emission (SASE), (2) regenerative amplification (RAFEL), or (3) self-seeding (SS-FEL). Model accelerator parameters are put forward to evaluate the impact of emission architecture on FEL output. Then, variations in the parameter space are applied to assess the potential impact to lithography operations, thereby establishing component sensitivity. The operating range of various accelerator components is discussed based on current accelerator performance demonstrated at various scientific user facilities. Finally, comparison of the performance between the model accelerator parameters and the variation in parameter space provides a means to evaluate the potential emission architectures. A scorecard is presented to facilitate this evaluation and provide a framework for future FEL design and enablement for EUV lithography applications.

  11. Plans for a far-infrared free-electron laser in India

    SciTech Connect

    Krishnagopal, S.; Kumar, V.; Ramamurthi, S.S.

    1995-12-31

    The Centre for Advanced Technology is building the INDUS complex of synchrotron radiation sources. As part of this programme it is also proposed to build a far-infrared free-electron laser oscillator. This will use a microtron injector and a 40 period undulator made of NdFeB permanent magnets, and is designed to law around 200 microns. We discuss details of the FEL design and the present status of experimental activities on this front.

  12. Infrared free electron laser enhanced transdermal drug delivery

    NASA Astrophysics Data System (ADS)

    Awazu, Kunio; Uchizono, Takeyuki; Suzuki, Sachiko; Yoshikawa, Kazushi

    2005-08-01

    It is necessary to control enhancement of transdermal drug delivery with non-invasive. The present study was investigated to assess the effectivity of enhancing the drug delivery by irradiating 6-μm region mid infrared free electron laser (MIR-FEL). The enhancement of transdermal drug (lidocaine) delivery of the samples (hairless mouse skin) irradiated with lasers was examined for flux (μg/cm2/h) and total penetration amount (μg/cm2) of lidocaine by High performance Liquid Chromatography (HPLC). The flux and total amount penatration date was enhanced 200-300 fold faster than the control date by the laser irradiation. FEL irradiating had the stratum corneum, and had the less thermal damage in epidermis. The effect of 6-μm region MIR-FEL has the enhancement of transdermal drug delivery without removing the stratum corneum because it has the less thermal damage. It leads to enhancement drug delivery system with non-invasive laser treatment.

  13. Optical Shaping of X-Ray Free-Electron Lasers

    NASA Astrophysics Data System (ADS)

    Marinelli, A.; Coffee, R.; Vetter, S.; Hering, P.; West, G. N.; Gilevich, S.; Lutman, A. A.; Li, S.; Maxwell, T.; Galayda, J.; Fry, A.; Huang, Z.

    2016-06-01

    In this Letter we report the experimental demonstration of a new temporal shaping technique for x-ray free-electron lasers (FELs). This technique is based on the use of a spectrally shaped infrared (IR) laser and allows optical control of the x-ray generation process. By accurately manipulating the spectral amplitude and phase of the IR laser, we can selectively modify the electron bunch longitudinal emittance thus controlling the duration of the resulting x-ray pulse down to the femtosecond time scale. Unlike other methods currently in use, optical shaping is directly applicable to the next generation of high-average power x-ray FELs such as the Linac Coherent Light Source-II or the European X-FEL, and it enables pulse shaping of FELs at the highest repetition rates. Furthermore, this laser-shaping technique paves the way for flexible tailoring of complex multicolor FEL pulse patterns required for nonlinear multidimensional x-ray spectroscopy as well as novel multicolor diffraction imaging schemes.

  14. Storage ring two-color free-electron laser

    DOE PAGES

    Yan, J.; Hao, H.; Li, J. Y.; ...

    2016-07-05

    We report a systematic experimental study of a storage ring two-color free-electron laser (FEL) operating simultaneously in the infrared (IR) and ultraviolet (UV) wavelength regions. The two-color FEL lasing has been realized using a pair of dual-band high-reflectivity FEL mirrors with two different undulator configurations. We have demonstrated independent wavelength tuning in a wide range for each lasing color, as well as harmonically locked wavelength tuning when the UV lasing occurs at the second harmonic of the IR lasing. Precise power control of two-color lasing with good power stability has also been achieved. In addition, the impact of the degradationmore » of FEL mirrors on the two-color FEL operation is reported. Moreover, we have investigated the temporal structures of the two-color FEL beams, showing simultaneous two-color micropulses with their intensity modulations displayed as FEL macropulses.« less

  15. Raman free-electron laser with a coaxial wiggler

    NASA Astrophysics Data System (ADS)

    Farokhi, B.; Maraghechi, B.; Willett, J. E.

    2000-10-01

    A one-dimensional theory of the stimulated Raman scattering mechanism for a coaxial free-electron laser (FEL) is developed. The beam-frame FEL dispersion relation and a formula for the lab-frame spatial growth rate are derived. A numerical study of the growth rate for the coaxial wiggler is made and compared with that for the helical wiggler. Except for a part of the group II orbits, the growth rate is found to be less than the helical wiggler. Relativistic effects due to the transverse oscillation of electrons in the wiggler field prevent the FEL operation from approaching magnetoresonance. In the absence of these relativistic mass effects, the calculations show a magnetoresonance associated with the first spatial harmonic and a much narrower resonance at the third spatial harmonic.

  16. Recent Developments in Superconducting RF Free Electron Lasers

    SciTech Connect

    Lia Merminga

    2001-09-01

    Superconducting RF (SRF) Free Electron Lasers (FELs) worldwide are reviewed. Two examples of high performance SRF FELs are discussed in detail: First, the Tesla Test Facility (TTF) FEL at DESY, which recently demonstrated Self Amplified Spontaneous Emission (SASE) saturation at the wavelength of 98 nm, an important milestone towards X-ray FELs in the {angstrom} regime. Second, the Jefferson Lab IR FEL, which recently lased with 2.1 kW of average power while energy recovering 5 mA of average current, an important milestone towards high average power FELs and towards Energy Recovering Linacs (ERLs) in general. We discuss the scientific potential and accelerator physics challenges of both classes of SRF-driven FELs.

  17. Conceptual design of industrial free electron laser using superconducting accelerator

    SciTech Connect

    Saldin, E.L.; Schneidmiller, E.A.; Ulyanov, Yu.N.

    1995-12-31

    Paper presents conceptual design of free electron laser (FEL) complex for industrial applications. The FEL complex consists of three. FEL oscillators with the optical output spanning the infrared (IR) and ultraviolet (UV) wave-lengths ({lambda} = 0.3...20 {mu}m) and with the average output power 10 - 20 kW. The driving beam for the FELs is produced by a superconducting accelerator. The electron beam is transported to the FELs via three beam lines (125 MeV and 2 x 250 MeV). Peculiar feature of the proposed complex is a high efficiency of the. FEL oscillators, up to 20 %. This becomes possible due to the use of quasi-continuous electron beam and the use of the time-dependent undulator tapering.

  18. EIGENMODE ANALYSIS OF OPTICAL GUIDING IN FREE ELECTRON LASERS

    SciTech Connect

    Xie, M.; Deacon, D.A.G.; Madey, J.M.J.

    1989-03-01

    The spatial properties of the optical field and hence the performance of a free electron laser depend on the fact that the electron beam, which acts as both an amplifying and a refractive medium, is transversely nonuniform. Under certain circumstances, optical guiding may be realized, where the optical field is stably confined near the electron beam and amplified along the beam over many Rayleigh ranges. We show that the three-dimensional evolution of the optical field through the interaction region can be determined by a guided mode expansion before saturation. Optical guiding occurs when the fundamental growing mode becomes dominant. The guided mode expansion is made possible by implementing the biorthogonality of the eigenmodes of the coupled electron-beam-optical-wave system. The eigenmodes are found to be of vectorial form with three components; one specifies the guided optical mode and the other two describe the density and the energy modulations of the electron beam.

  19. Optical analysis of high power free electron laser resonators

    SciTech Connect

    Knapp, C.E.; Viswanathan, V.K.; Appert, Q.D.; Bender, S.C.; McVey, B.D.

    1987-01-01

    The first part of this paper briefly describes the optics code used at Los Alamos National Laboratory to do optical analyses of various components of a free electron laser. The body of the paper then discusses the recent results in modeling low frequency gratings and ripple on the surfaces of liquid-cooled mirrors. The ripple is caused by structural/thermal effects in the mirror surface due to heating by optical absorption in high power resonators. Of interest is how much ripple can be permitted before diffractive losses or optical mode distortions become unacceptable. Preliminary work is presented involving classical diffraction problems to support the ripple study. The limitations of the techniques are discussed and the results are compared to experimental results where available.

  20. Radiofrequency superconductivity applied to free-electron lasers

    SciTech Connect

    Bohn, C.L.; Benson, S.V.

    1998-01-01

    Low wall losses and low wakefields inherent in superconducting radiofrequency (srf) cavities make them attractive candidates for accelerators that operate efficiently at high continuous-wave (cw) gradients. Such accelerators are desirable for free-electron lasers (FELs) that extract high-power cw light from a high-average-current electron beam, or that produce ultrashort-wavelength light from a high-energy electron beam. Efficiency is a prime consideration in the former case, while high electron-beam quality is a prime consideration in the latter case. This paper summarizes the status of FEL projects involving srf accelerators. It also introduces Jefferson Lab`s srf FEL and surveys its design because it is a new machine, with commissioning having commenced in October 1997. Once commissioning is complete, this FEL should produce tunable, cw, kW-level light at 3-6 {mu}m wavelength.

  1. following an electron bunch for free electron laser

    SciTech Connect

    2012-01-01

    A video artist's ultra-slow-motion impression of an APEX-style electron gun firing a continuous train of electron bunches into a superconducting linear accelerator (in reality this would happen a million times a second). As they approach the speed of light the bunches contract, maintaining beam quality. After acceleration, the electron bunches are diverted into one or more undulators, the key components of free electron lasers. Oscillating back and forth in the changing magnetic field, they create beams of structured x-ray pulses. Before entering the experimental areas the electron bunches are diverted to a beam dump. (Animation created by Illumina Visual, http://www.illuminavisual.com/, for Lawrence Berkeley National Laboratory. Music for this excerpt, "Feeling Dark (Behind The Mask)" is by 7OOP3D http://ccmixter.org/files/7OOP3D/29126 and is licensed under a Creative Commons license: http://creativecommons.org/licenses/by-nc/3.0/)

  2. Free-electron lasers with very slow wiggler taper

    NASA Astrophysics Data System (ADS)

    Bosley, D. L.; Kevorkian, J.

    1990-09-01

    A highly accurate, explicit asymptotic solution of the electron energy and phase is found for a class of free-electron lasers with very long wavelength beams, very low electron energies, and very slow taper of the wiggler field relative to the wiggler period. Dimensionless variables are defined and normalized, and three small parameters which characterize the operation of the FEL are identified. Because of the explicit nature of the solution, our results may be directly used to calculate features such as the escape distance of the electron from the potential well and the effects of the various physical parameters. One important advantage of the very slow wiggler taper is the increased efficiency of the energy transfer from the electron beam to the signal field due to increased bucket width. Numerical calculations are performed to verify all results.

  3. Free-electron lasers with very slow wiggler taper

    NASA Astrophysics Data System (ADS)

    Bosley, D. L.; Kevorkian, J.

    1991-04-01

    A highly accurate, explicit asymptotic solution of the electron energy and phase is found for a class of free-electron lasers (FELs) with very long wavelength beams, very low electron energies, and very slow taper of the wiggler field relative to the wiggler period. Dimensionless variables are defined and normalized, and three small parameters which characterize the operation of the FEL are identified. Due to the explicit asymptotic nature of the solution, the results may be directly used to calculate features such as the escape distance of the electron from the potential well and the effects of the various physical parameters. One important advantage of the very slow wiggler taper is the increased efficiency of the energy transfer from the electron beam to the signal field due to increased bucket width. Numerical calculations are performed to verify all results.

  4. Focusing mirror for x-ray free-electron lasers

    SciTech Connect

    Mimura, Hidekazu; Kimura, Takashi; Yamakawa, Daisuke; Matsuyama, Satoshi; Morita, Shinya; Uehara, Yoshihiro; Ohmori, Hitoshi; Lin, Weimin; Yumoto, Hirokatsu; Ohashi, Haruhiko

    2008-08-15

    We present the design, fabrication, and evaluation of a large total-reflection mirror for focusing x-ray free-electron laser beams to nanometer dimensions. We used an elliptical focusing mirror made of silicon that was 400 mm long and had a focal length of 550 mm. Electrolytic in-process dressing grinding was used for initial-step figuring and elastic emission machining was employed for final figuring and surface smoothing. A figure accuracy with a peak-to-valley height of 2 nm was achieved across the entire area. Characterization of the focused beam was performed at BL29XUL of SPring-8. The focused beam size was 75 nm at 15 keV, which is almost equal to the theoretical size.

  5. Thermal effect on prebunched two-beam free electron laser

    NASA Astrophysics Data System (ADS)

    Mirian, N. S.; Maraghechi, B.

    2013-08-01

    A numerical simulation in one-dimension is conducted to study the two-beam free electron laser. The fundamental resonance of the fast electron beam coincides with the fifth harmonic of the slow electron beam in order to generate extreme ultraviolet radiation. Thermal effect in the form of the longitudinal velocity spread is included in the analysis. In order to reduce the length of the wiggler, prebunched slow electron beam is considered. The evaluation of the radiation power, bunching parameter, distribution function of energy, and the distribution function of the pondermotive phase is studied. Sensitivity of the power of the fifth harmonic to the jitter in the energy difference between the two beams is also studied. A phase space is presented that shows the trapped electrons at the saturation point.

  6. A free-electron laser at the Orsay storage ring

    NASA Astrophysics Data System (ADS)

    Elleaume, P.

    1984-12-01

    The design and operation of the free-electron-laser (FEL) apparatus installed at the Orsay storage-ring particle accelerator are characterized and illustrated with diagrams, graphs, and oscilloscope trades of the output. The history and fundamental physics of FELs are reviewed; the electron beam of the Orsay ring, the optical klystron (used instead of a wiggler due to the low gain klystron available), and the optical cavity (using a high-reflectance mirror) of the Orsay FEL are described; and experimental data on the spectrum, microtemporal and macrotemporal structure, and mean power of the FEL output are presented. The performance of the Orsay FEL is found to be in good agreement with the predictions of a classical theory based on the Lorentz force and the Maxwell equations.

  7. Harmonic Inverse Free Electron Laser Micro-Buncher

    NASA Astrophysics Data System (ADS)

    Pottorf, S.; Wang, X. J.

    2002-04-01

    The Inverse Free Electron (IFEL) and its applications are first briefly reviewed. The concept of harmonic IFEL was proposed for electron beam micro-bunching. A tightly micro-bunched electron beam could be used either as a laser accelerator injector or for femto-second X-ray generation by ultra-high harmonic radiation. For a planar undulator, the electron beam is strongly coupled to both the fundamental and odd harmonic if the undulator parameter is greater than 1, K > 1. The 1-D equation of motion for the IFEL was first extended to the third harmonic. 1-D simulations were performed for both fundamental only IFEL and harmonic IFEL. Two configurations of harmonic IFEL were considered. First, a single undulator with both fundamental and third harmonic IFEL presented simultaneously was studied. Second, a configuration employing a fundamental IFEL followed by a third harmonic IFEL. Better and efficient bunching was achieved for both harmonic IFEL compared to the fundamental IFEL only.

  8. The Study of Advanced Accelerator Physics Research at UCLA Using the ATF at BNL: Vacuum Acceleration by Laser of Free Electrons

    SciTech Connect

    Cline, David B.

    2016-09-07

    An experiment was designed and data were taken to demonstrate that a tightly focused laser on vacuum can accelerate an electron beam in free space. The experiment was proof-of-principle and showed a clear effect for the laser beam off and on. The size of the effect was about 20% and was consistent over 30 laser and beam shots.

  9. Coherent-state description of free-electron lasers

    NASA Astrophysics Data System (ADS)

    Lee, Ching Tsung

    1990-12-01

    It is generally accepted that the overall performance of free-electron lasers (FEL) can be understood without quantum mechanics. However, there are features of FEL such as photon statistics which can only be described quantum-mechanically. Although the majority of quantum-mechanical studies of FEL are devoted to one-particle models, there are also many studies on many-body effects of FEL. Unfortunately, the mathematical derivations of these studies are so complicated that it is not easy to follow the developments with a clearer picture in mind. The origin of the problem is the quantum recoils of the electrons. So we try to gain a clearer picture of the many-body effects by making the recoilless approximation. A simple model of FEL consists of a beam of relativistic electrons propagating through a spatially periodic magnetostatic wiggler field. The resulting laser output is propagating along the same direction as that of the electron beam. Quantum-mechanical analysis of FEL are usually based on the Bambini-Renieri frame which moves in the same direction as the propagating laser beam with a relativistic speed so that: (1) the wiggler field appears almost as a plane-wave radiation, (2) the frequency of the wiggler field coincides with that of the laser, and (3) the electron motion is nonrelativistic. Although in reality the laser beam can only derive its energy at the expense of the kinetic energy of the electrons, it appears in the Bambini-Renieri frame as if the photons of the laser were scattered from the fictitious photons of the wiggler field by the electrons.

  10. An inverse free electron laser accelerator: Experiment and theoretical interpretation

    SciTech Connect

    Fang, Jyan-Min

    1997-01-01

    Experimental and numerical studies of the Inverse Free Electron Laser using a GW-level 10.6 μm CO2 laser have been carried out at Brookhaven`s Accelerator Test Facility. An energy gain of 2.5 % (ΔE/E) on a 40 MeV electron beam has been observed E which compares well with theory. The effects on IFEL acceleration with respect to the variation of the laser electric field, the input electron beam energy, and the wiggler magnetic field strength were studied, and show the importance of matching the resonance condition in the IFEL. The numerical simulations were performed under various conditions and the importance of the electron bunching in the IFEL is shown. The numerical interpretation of our IFEL experimental results was examined. Although good numerical agreement with the experimental results was obtained, there is a discrepancy between the level of the laser power measured in the experiment and used in the simulation, possibly due to the non-Gaussian profile of the input high power laser beam. The electron energy distribution was studied numerically and a smoothing of the energy spectrum by the space charge effect at the location of the spectrometer was found, compared with the spectrum at the exit of the wiggler. The electron bunching by the IFEL and the possibility of using the IFEL as an electron prebuncher for another laser-driven accelerator were studied numerically. We found that bunching of the electrons at 1 meter downstream from the wiggler can be achieved using the existing facility. The simulation shows that there is a fundamental difference between the operating conditions for using the IFEL as a high gradient accelerator, and as a prebuncher for another accelerator.

  11. Free-electron laser effects on fibrin tissue glue: a preliminary study

    NASA Astrophysics Data System (ADS)

    Joos, Karen M.; Topadze, Katie; Shieh, Charles; Shen, Jin-Hui; Casagrande, Vivien A.

    2000-06-01

    One glaucoma challenge is the treatment of leaking trabeculectomy blebs. Simple methods such as patching, autologous blood injection, compression sutures or cyanoacrylate glue application often fail. Because the conjunctiva is thin and ischemic, it often can't be sutured together so major surgery is required to excise the thin tissue and advance healthy conjunctiva. We report the preliminary results of Tisseel and Tisseel treated with two wavelengths from Vanderbilt's free electron laser placed on leaking trabeculectomy bleb holes in Dutch belted rabbits. The holes were healed at one week in the sutured group and in the 7.7 micrometer FEL-treated Tisseel group. One hole was healed in the cyanoacrylate glue-treated group. Holes remained in the other treatment groups. Tisseel irradiated with 7.7 micrometer energy from the free electron laser may promote healing of trabeculectomy bleb holes.

  12. A wide bandwidth free-electron laser with mode locking using current modulation.

    SciTech Connect

    Kur, E.; Dunning, D. J.; McNeil, B. W. J.; Wurtele, J.; Zholents, A. A. )

    2011-01-20

    A new scheme for mode locking a free-electron laser amplifier is proposed based on electron beam current modulation. It is found that certain properties of the original concept, based on the energy modulation of electrons, are improved including the spectral brightness of the source and the purity of the series of short pulses. Numerical comparisons are made between the new and old schemes and between a mode-locked free-electron laser and self-amplified spontaneous emission free-electron laser. Illustrative examples using a hypothetical mode-locked free-electron laser amplifier are provided. The ability to generate intense coherent radiation with a large bandwidth is demonstrated.

  13. Hemostatic properties of the free-electron laser

    NASA Astrophysics Data System (ADS)

    Cram, Gary P., Jr.; Copeland, Michael L.

    1998-09-01

    We have investigated the hemostatic properties of the free-electron laser (FEL) and compared these properties to the most commonly used commercial lasers in neurosurgery, CO 2 and Nd:YAG, using an acute canine model. Arterial and venous vessels, of varying diameters from 0.1 to 1.0 mm, were divided with all three lasers. Analysis of five wavelengths of the FEL (3.0, 4.5, 6.1, 6.45, and 7.7 microns) resulted in bleeding without evidence of significant coagulation, regardless of whether the vessel was an artery or vein. Hemorrhage from vessels less than 0.4 mm diameter was subsequently easily controlled with Gelfoam® (topical hemostatic agent) alone, whereas larger vessels required bipolar electrocautery. No significant charring, or contraction of the surrounding parenchyma was noted with any of the wavelengths chosen from FEL source. The CO 2 laser, in continuous mode, easily coagulated vessels with diameters of 4 mm and less, while larger vessels displayed significant bleeding requiring bipolar electrocautery for control. Tissue charring was noted with application of the CO 2 laser. In super pulse mode, the CO 2 laser exhibited similar properties, including significant charring of the surrounding parenchyma. The Nd:YAG coagulated all vessels tested up to 1.4 mm, which was the largest diameter cortical artery found, however this laser displayed significant and extensive contraction and retraction of the surrounding parenchyma. In conclusion, the FEL appears to be a poor hemostatic agent. Our results did not show any benefit of the FEL over current conventional means of achieving hemostasis. However, control of hemorrhage was easily achieved with currently used methods of hemostasis, namely Gelfoam® or bipolar electrocuatery. Although only cortical vessels in dogs were tested, we feel this data can be applied to all animals, including humans, and the peripheral, as well as central, vasculature, as our data on the CO 2 and Nd:YAG appear to closely support previous

  14. Deliberate misalignment in free electron lasers with a hole coupling

    SciTech Connect

    Zhulin, V.I.

    1995-12-31

    In a conventional laser operation misalignment of resonator mirrors leads usually to undesirable effects and has to be avoided. But in some certain types of cavity configurations deliberate introduction of misalignment makes it possible to improve considerably the characteristics of out-put radiation. The example of such configurations is an optical scheme with hole coupling. Two options are considered: (1) the free electron laser (FEL) with the radiation output through the on-axis hole at the exit mirror; (2) the external resonator (used for pulse stacking) where the exit FEL radiation enters this resonator through the on-axis hole at the input mirror. These configurations are investigated with the continuous wave 3-D code. It is shown that in a FEL with a hole coupling the transverse distribution of intracavity mode is characterised under certain conditions by a on-axis dip. The introduction of deliberate misalignment, characterised by a mirror tilt angle {theta}, leads to a shift and variation of the spacial structure. It is shown that due to the complicated structure of intracavity field, the dependences of the output power P on {theta} become nonmonotonic. For optimal value of {theta} = {theta}{sub opt} the output power could be much bigger than for the case {theta} = 0. Moreover, the introduction of deliberate misalignment into optical cavity provides an opportunity not only to increase the output power but also to smooth the dependences of the output characteristics on the radiation wavelength.

  15. Pulse Duration of Seeded Free-Electron Lasers

    DOE PAGES

    Finetti, Paola; Hoppner, Hauke; Allaria, Enrico; ...

    2017-06-16

    The pulse duration, and, more generally, the temporal intensity profile of free-electron laser (FEL) pulses, is of utmost importance for exploring the new perspectives offered by FELs; it is a nontrivial experimental parameter that needs to be characterized. We measured the pulse shape of an extreme ultraviolet externally seeded FEL operating in high-gain harmonic generation mode. Two different methods based on the cross-correlation of the FEL pulses with an external optical laser were used. The two methods, one capable of single-shot performance, may both be implemented as online diagnostics in FEL facilities. The measurements were carried out at the seededmore » FEL facility FERMI. The FEL temporal pulse characteristics were measured and studied in a range of FEL wavelengths and machine settings, and they were compared to the predictions of a theoretical model. Finally, the measurements allowed a direct observation of the pulse lengthening and splitting at saturation, in agreement with the proposed theory.« less

  16. Coherent and spontaneous emission in the quantum free electron laser

    SciTech Connect

    Robb, G. R. M.; Bonifacio, R.

    2012-07-15

    We present an analysis of quantum free electron laser (QFEL) dynamics including the effects of spontaneous emission. The effects of spontaneous emission are undesirable for coherent short-wave generation using FELs and have been shown in previous studies to limit the capabilities of classical self amplified spontaneous emission (SASE)-FELs at short wavelengths {approx}1 A due to growth of electron beam energy spread. As one of the attractive features of the QFEL is its potential as a relatively compact coherent x-ray source, it is important to understand the role of spontaneous emission, but to date there has not been a model which is capable of consistently describing the dynamics of both coherent FEL emission and incoherent spontaneous emission. In this paper, we present such a model, and use it to show that the limitations imposed by spontaneous emission on coherent FEL operation are significantly different in the quantum regime to those in the classical regime. An example set of parameters constituting a QFEL using electron and laser parameters which satisfy the condition for neglect of spontaneous emission during coherent QFEL emission is presented.

  17. Cartilage ablation studies using mid-IR free electron laser

    NASA Astrophysics Data System (ADS)

    Youn, Jong-In; Peavy, George M.; Venugopalan, Vasan

    2005-04-01

    The ablation rate of articular cartilage and fibrocartilage (meniscus), were quantified to examine wavelength and tissue-composition dependence of ablation efficiency for selected mid-infrared wavelengths. The wavelengths tested were 2.9 um (water dominant absorption), 6.1 (protein and water absorption) and 6.45 um (protein dominant absorption) generated by the Free Electron Laser (FEL) at Vanderbilt University. The measurement of tissue mass removal using a microbalance during laser ablation was conducted to determine the ablation rates of cartilage. The technique can be accurate over methods such as profilometer and histology sectioning where tissue surface and the crater morphology may be affected by tissue processing. The ablation efficiency was found to be dependent upon the wavelength. Both articular cartilage and meniscus (fibrocartilage) ablations at 6.1 um were more efficient than those at the other wavelengths evaluated. We observed the lowest ablation efficiency of both types of cartilage with the 6.45 um wavelength, possibly due to the reduction in water absorption at this wavelength in comparison to the other wavelengths that were evaluated.

  18. Free electron lasers: Present status and future challenges

    SciTech Connect

    Barletta, W A; Corlett, J N; Emma, P; Huang, Z; Kim, K -J; Lindberg, R; Murphy, J B; Neil, G P; Nguyen, D C; Pellegrini, C; Rimmer, R A; Sannibale, F; Stupakov, G; Walker, R P; Zholents, A A

    2010-06-01

    With the scientific successes of the soft X-ray FLASH facility in Germany and the recent spectacular commissioning of the Linac Coherent Light Source at SLAC, free electron lasers are poised to take center stage as the premier source of tunable, intense, coherent photons of either ultra-short time resolution or ultra-fine spectral resolution, from the far infrared to the hard X-ray regime. This paper examines the state of the art in FEL performance and the underlying enabling technologies. It evaluates the state of readiness of the three basic machine architectures—SASE FELs, seeded FELs, and FEL oscillators—for the major X-ray science user facilities on the 5–10 years time scale and examines the challenges that lie ahead for FELs to achieve their full potential throughout the entire spectral range. In soft and hard X-rays, high longitudinal coherence, in addition to full transverse coherence, will be the key performance upgrade; ideas using laser-based or self-seeding or oscillators can be expected to be qualitatively superior to today's SASE sources. Short pulses, from femtoseconds to attoseconds, can be realistically envisioned. With high repetition rate electron sources coupled to superconducting radiofrequency linear accelerators, unprecedented average beam brightness will be possible and many users would be served simultaneously by a single accelerator complex.

  19. Free electron lasers: Present status and future challenges

    NASA Astrophysics Data System (ADS)

    Barletta, W. A.; Bisognano, J.; Corlett, J. N.; Emma, P.; Huang, Z.; Kim, K.-J.; Lindberg, R.; Murphy, J. B.; Neil, G. R.; Nguyen, D. C.; Pellegrini, C.; Rimmer, R. A.; Sannibale, F.; Stupakov, G.; Walker, R. P.; Zholents, A. A.

    2010-06-01

    With the scientific successes of the soft X-ray FLASH facility in Germany and the recent spectacular commissioning of the Linac Coherent Light Source at SLAC, free electron lasers are poised to take center stage as the premier source of tunable, intense, coherent photons of either ultra-short time resolution or ultra-fine spectral resolution, from the far infrared to the hard X-ray regime. This paper examines the state of the art in FEL performance and the underlying enabling technologies. It evaluates the state of readiness of the three basic machine architectures—SASE FELs, seeded FELs, and FEL oscillators—for the major X-ray science user facilities on the 5-10 years time scale and examines the challenges that lie ahead for FELs to achieve their full potential throughout the entire spectral range. In soft and hard X-rays, high longitudinal coherence, in addition to full transverse coherence, will be the key performance upgrade; ideas using laser-based or self-seeding or oscillators can be expected to be qualitatively superior to today's SASE sources. Short pulses, from femtoseconds to attoseconds, can be realistically envisioned. With high repetition rate electron sources coupled to superconducting radiofrequency linear accelerators, unprecedented average beam brightness will be possible and many users would be served simultaneously by a single accelerator complex.

  20. Ultraviolet Free Electron Laser Facility preliminary design report

    SciTech Connect

    Ben-Zvi, I.

    1993-02-01

    This document, the Preliminary Design Report (PDR) for the Brookhaven Ultraviolet Free Electron Laser (UV FEL) facility, describes all the elements of a facility proposed to meet the needs of a research community which requires ultraviolet sources not currently available as laboratory based lasers. Further, for these experiments, the requisite properties are not extant in either the existing second or upcoming third generation synchrotron light sources. This document is the result of our effort at BNL to identify potential users, determine the requirements of their experiments, and to design a facility which can not only satisfy the existing need, but have adequate flexibility for possible future extensions as need dictates and as evolving technology allows. The PDR is comprised of three volumes. In this, the first volume, background for the development of the proposal is given, including descriptions of the UV FEL facility, and representative examples of the science it was designed to perform. Discussion of the limitations and potential directions for growth are also included. A detailed description of the facility design is then provided, which addresses the accelerator, optical, and experimental systems. Information regarding the conventional construction for the facility is contained in an addendum to volume one (IA).

  1. Coherent harmonic generation in storage ring free electron lasers

    NASA Astrophysics Data System (ADS)

    Longhi, Emily C.

    This dissertation presents work on the production of coherent harmonic radiation from the optical klystron (OK-4) installed on the electron storage ring which is part of the Duke University Free Electron Laser (FEL) Laboratory. It has long been known theoretically that free electron lasers (FELs) can produce coherent light at various harmonics of the fundamental lasing wavelength. This presents interesting opportunities for using the Duke OK-4 FEL as a tunable coherent vacuum ultraviolet and soft x-ray light source. In this disseration, we present the first experimental results of self-seeded coherent harmonic generation in a storage ring FEL. We describe the specialized tools needed for coherent harmonic production and observation, and present data showing the various harmonics and wavelengths achieved. We also present the results of detailed studies into two different experi mental harmonic generation methods, as well as the dependence of harmonic generation on various storage ring and optical klystron parameters. A similar project, at Elettra, Sincrotrone Trieste, Italy, which has an active collaboration with Duke FEL Lab members, has produced similar results, a selection of which we also present. The basic principle of an FEL is that under certain conditions, a beam of relativistic electrons can produce coherent radiation. In the case of the OK-4 FEL, electrons spend part of their orbit in an optical klystron where they interact with ra diation trapped in the optical cavity at the same time that they are passing through a set of magnets which perturb their orbit sinusoidally. The net result of these interactions is that energy is transferred from the electrons into the radiation field. Without harmonics, the OK-4 FEL can lase at fundamental wavelengths between 193.7 and 2,100nm using a variety of mirrors. With a single set of mirrors in the optical klystron, it is possible to have tunability of the lasing wavelength up to 20%. Coherent harmonic generation

  2. A THz spectrometer combining the free electron laser FLARE with 33 T magnetic fields

    NASA Astrophysics Data System (ADS)

    Ozerov, M.; Bernáth, B.; Kamenskyi, D.; Redlich, B.; van der Meer, A. F. G.; Christianen, P. C. M.; Engelkamp, H.; Maan, J. C.

    2017-02-01

    The free electron laser Free electron Laser for Advanced spectroscopy and high Resolution Experiments (FLARE) at the FELIX Laboratory generates powerful radiation in the frequency range of 0.3-3 THz. This light, in combination with 33 T Bitter magnets at the High Field Magnet Laboratory, provides the unique opportunity to perform THz magneto spectroscopy with light intensities many orders of magnitude higher than provided by conventional sources. The performance of the THz spectrometer is measured via high-field electron spin resonance (ESR) in the paramagnetic benchmark system 2,2-diphenyl-1-picrylhydrazyl (DPPH). The narrow ESR linewidth of DPPH allows us to resolve a fine structure with 3 GHz spacing, demonstrating a considerable coherence of the individual THz micropulses of FLARE. The spectral resolution Δ ν / ν is better than 0.1%, which is an order of magnitude higher than typical values for a rf-linac based free electron laser. The observed coherence of the high power THz micropulses is a prerequisite for resonant control of matter, such as THz electron spin echo spectroscopy.

  3. Intense microwave generation using free-electron lasers

    SciTech Connect

    Orzechowski, T.J.

    1990-09-01

    In this paper, I will describe a free-electron laser amplifier which operated in the microwave regime. This device, called the Electron Laser Facility (ELF), used an electron beam generated by a Linear Induction Accelerator (LIA). ELF operated as a single pass amplifier at 35 and 140 GHz. Because the device had no cavity, we could study the FEL physics independent of cavity considerations. With a sufficiently large input signal, growth of the signal from noise on the beam did not influence the performance. This device demonstrated significant gain and allowed us to investigate such FEL phenomenon as saturation and synchrotron oscillation of the electrons trapped in the ponderomotive well. We were also able to study the phase shift of the radiation due to the real part of complex gain of the FEL. Because the interaction takes place in a waveguide, the FEL can couple to several spatial modes at a given frequency. The bunched electrons can radiate at harmonics of the fundamental and in this experiment we studied the evolution of the third harmonic. In this paper, I will describe the Electron Laser Facility. I will discuss the FEL performance with regard to gain, saturation, phase evolution, mode coupling and harmonic generation, I will briefly discuss a switching technique which allows the LIA to run at high average power. When driven by such a device, and FEL can produce high average power radiation. We will present the design for such a device which can be used to heat a tokamak plasma. This device is designed to operate at 250 GHz and produce an average power of 2 MW.

  4. An inverse free electron laser accelerator: Experiment and theoretical interpretation

    NASA Astrophysics Data System (ADS)

    Fang, Jyan-Min

    Experimental and numerical studies of the Inverse Free Electron Laser using a GW-level 10.6 /mu m CO2 laser have been carried out at Brookhaven's Accelerator Test Facility. An energy gain of 2.5% ([/Delta E/over E]) on a 40 MeV electron beam has been observed which compares well with theory. The effects on IFEL acceleration with respect to the variation of the laser electric field, the input electron beam energy, and the wiggler magnetic field strength were studied, and show the importance of matching the resonance condition in the IFEL. The numerical simulations were perforated under various conditions and the importance of the electron bunching in the IFEL is shown. The numerical interpretation of our IFEL experimental results was examined. Although good numerical agreement with the experimental results was obtained, there is a discrepancy between the level of the laser power measured in the experiment and used in the simulation, possibly due to the non-Gaussian profile of the input high power laser beam. The electron energy distribution was studied numerically and a smoothing of the energy spectrum by the space charge effect at the location of the spectrometer was found, compared with the spectrum at the exit of the wiggler. The electron bunching by the IFEL and the possibility of using the IFEL as an electron prebuncher for another laser-driven accelerator were studied numerically. We found that bunching of the electrons at 1 meter downstream from the wiggler can be achieved using the existing facility. The simulation shows that there is a fundamental difference between the operating conditions for using the IFEL as a high gradient accelerator, and as a prebuncher for another accelerator. For a high gradient accelerator, the IFEL requires the bunching of the electrons inside the wiggler for optimal energy gain, whereas using the IFEL as a prebuncher for another accelerator, a moderate energy gain may be sufficient for the best electron bunching results at a

  5. Self-fields in free-electron lasers

    SciTech Connect

    Roberson, C.W.; Hafizi, B.

    1995-12-31

    We have analyzed the free-electron laser (FEL) interaction in the high gain Compton regime. The theory has been extended to include self field effects on FEL operation. These effects are particularly important in compact, low voltage FELs. The theory applies to the case where the optical beam is guided by the electron beam by gain focusing and maintains a constant profile through the wiggler. The finite-emittance electron beam, in turn, is matched to the wiggler. The bitatron motion of the electrons is determined by (i) the focusing force due to wiggler gradients and, (ii) the repulsive force due to self-fields. Based on the single-electron equations, it can be shown that self-field forces tend to increase the period of transverse oscillations of electrons in the wiggler. In the limit, the flow of electrons is purely laminar, with a uniform axial velocity along and across the wiggler resulting in an improved beam quality. We shall also discuss the effects of beam compression on growth rate.

  6. Structural enzymology using X-ray free electron lasers

    PubMed Central

    Kupitz, Christopher; Olmos, Jose L.; Holl, Mark; Tremblay, Lee; Pande, Kanupriya; Pandey, Suraj; Oberthür, Dominik; Hunter, Mark; Liang, Mengning; Aquila, Andrew; Tenboer, Jason; Calvey, George; Katz, Andrea; Chen, Yujie; Wiedorn, Max O.; Knoska, Juraj; Meents, Alke; Majriani, Valerio; Norwood, Tyler; Poudyal, Ishwor; Grant, Thomas; Miller, Mitchell D.; Xu, Weijun; Tolstikova, Aleksandra; Morgan, Andrew; Metz, Markus; Martin-Garcia, Jose M.; Zook, James D.; Roy-Chowdhury, Shatabdi; Coe, Jesse; Nagaratnam, Nirupa; Meza, Domingo; Fromme, Raimund; Basu, Shibom; Frank, Matthias; White, Thomas; Barty, Anton; Bajt, Sasa; Yefanov, Oleksandr; Chapman, Henry N.; Zatsepin, Nadia; Nelson, Garrett; Weierstall, Uwe; Spence, John; Schwander, Peter; Pollack, Lois; Fromme, Petra; Ourmazd, Abbas; Phillips, George N.; Schmidt, Marius

    2016-01-01

    Mix-and-inject serial crystallography (MISC) is a technique designed to image enzyme catalyzed reactions in which small protein crystals are mixed with a substrate just prior to being probed by an X-ray pulse. This approach offers several advantages over flow cell studies. It provides (i) room temperature structures at near atomic resolution, (ii) time resolution ranging from microseconds to seconds, and (iii) convenient reaction initiation. It outruns radiation damage by using femtosecond X-ray pulses allowing damage and chemistry to be separated. Here, we demonstrate that MISC is feasible at an X-ray free electron laser by studying the reaction of M. tuberculosis ß-lactamase microcrystals with ceftriaxone antibiotic solution. Electron density maps of the apo-ß-lactamase and of the ceftriaxone bound form were obtained at 2.8 Å and 2.4 Å resolution, respectively. These results pave the way to study cyclic and non-cyclic reactions and represent a new field of time-resolved structural dynamics for numerous substrate-triggered biological reactions. PMID:28083542

  7. Electrostatic-accelerator free-electron lasers for power beaming

    SciTech Connect

    Pinhasi, Y.; Yakover, I.M.; Gover, A.

    1995-12-31

    Novel concepts of electrostatic-accelerator free-electron lasers (EA-FELs) for energy transfer through the atmosphere are presented. The high average power attained from an EA-FEL makes it an efficient source of mm-wave for power beaming from a ground stations. General aspects of operating the FEL as a high power oscillator (like acceleration voltage, e-beam. current, gain and efficiency) are studied and design considerations are described. The study takes into account requirements of power beaming application such as characteristic dips in the atmospheric absorption spectrum, sizes of transmitting and receiving antennas and meteorological conditions. We present a conceptual design of a moderate voltage (.5-3 MeV) high current (1-10 Amp) EA-FEL operating at mm-wavelength bands, where the atmospheric attenuation allows efficient power beaming to space. The FEL parameters were calculated, employing analytical and numerical models. The performance parameters of the FEL (power, energy conversion efficiency average power) will be discussed in connection to the proposed application.

  8. The physics of x-ray free-electron lasers

    NASA Astrophysics Data System (ADS)

    Pellegrini, C.; Marinelli, A.; Reiche, S.

    2016-01-01

    X-ray free-electron lasers (x-ray FELs) give us for the first time the possibility to explore structures and dynamical processes of atomic and molecular systems at the angstrom-femtosecond space and time scales. They generate coherent photon pulses with time duration of a few to 100 fs, peak power of 10 to 100 GW, over a wavelength range extending from about 100 nm to less than 1 Å. Using these novel and unique capabilities new scientific results are being obtained in atomic and molecular sciences, in areas of physics, chemistry, and biology. This paper reviews the physical principles, the theoretical models, and the numerical codes on which x-ray FELs are based, starting from a single electron spontaneous undulator radiation to the FEL collective instability of a high density electron beam, strongly enhancing the electromagnetic radiation field intensity and its coherence properties. A short review is presented of the main experimental properties of x-ray FELs, and the results are discussed of the most recent research to improve their longitudinal coherence properties, increase the peak power, and generate multicolor spectra.

  9. High efficiency, multiterawatt x-ray free electron lasers

    NASA Astrophysics Data System (ADS)

    Emma, C.; Fang, K.; Wu, J.; Pellegrini, C.

    2016-02-01

    In this paper we present undulator magnet tapering methods for obtaining high efficiency and multiterawatt peak powers in x-ray free electron lasers (XFELs), a key requirement for enabling 3D atomic resolution single molecule imaging and nonlinear x-ray science. The peak power and efficiency of tapered XFELs is sensitive to time dependent effects, like synchrotron sideband growth. To analyze this dependence in detail we perform a comparative numerical optimization for the undulator magnetic field tapering profile including and intentionally disabling these effects. We show that the solution for the magnetic field taper profile obtained from time independent optimization does not yield the highest extraction efficiency when time dependent effects are included. Our comparative optimization is performed for a novel undulator designed specifically to obtain TW power x-ray pulses in the shortest distance: superconducting, helical, with short period and built-in strong focusing. This design reduces the length of the breaks between modules, decreasing diffraction effects, and allows using a stronger transverse electron focusing. Both effects reduce the gain length and the overall undulator length. We determine that after a fully time dependent optimization of a 100 m long Linac coherent light source-like XFEL we can obtain a maximum efficiency of 7%, corresponding to 3.7 TW peak radiation power. Possible methods to suppress the synchrotron sidebands, and further enhance the FEL peak power, up to about 6 TW by increasing the seed power and reducing the electron beam energy spread, are also discussed.

  10. Structural enzymology using X-ray free electron lasers.

    PubMed

    Kupitz, Christopher; Olmos, Jose L; Holl, Mark; Tremblay, Lee; Pande, Kanupriya; Pandey, Suraj; Oberthür, Dominik; Hunter, Mark; Liang, Mengning; Aquila, Andrew; Tenboer, Jason; Calvey, George; Katz, Andrea; Chen, Yujie; Wiedorn, Max O; Knoska, Juraj; Meents, Alke; Majriani, Valerio; Norwood, Tyler; Poudyal, Ishwor; Grant, Thomas; Miller, Mitchell D; Xu, Weijun; Tolstikova, Aleksandra; Morgan, Andrew; Metz, Markus; Martin-Garcia, Jose M; Zook, James D; Roy-Chowdhury, Shatabdi; Coe, Jesse; Nagaratnam, Nirupa; Meza, Domingo; Fromme, Raimund; Basu, Shibom; Frank, Matthias; White, Thomas; Barty, Anton; Bajt, Sasa; Yefanov, Oleksandr; Chapman, Henry N; Zatsepin, Nadia; Nelson, Garrett; Weierstall, Uwe; Spence, John; Schwander, Peter; Pollack, Lois; Fromme, Petra; Ourmazd, Abbas; Phillips, George N; Schmidt, Marius

    2017-07-01

    Mix-and-inject serial crystallography (MISC) is a technique designed to image enzyme catalyzed reactions in which small protein crystals are mixed with a substrate just prior to being probed by an X-ray pulse. This approach offers several advantages over flow cell studies. It provides (i) room temperature structures at near atomic resolution, (ii) time resolution ranging from microseconds to seconds, and (iii) convenient reaction initiation. It outruns radiation damage by using femtosecond X-ray pulses allowing damage and chemistry to be separated. Here, we demonstrate that MISC is feasible at an X-ray free electron laser by studying the reaction of M. tuberculosis ß-lactamase microcrystals with ceftriaxone antibiotic solution. Electron density maps of the apo-ß-lactamase and of the ceftriaxone bound form were obtained at 2.8 Å and 2.4 Å resolution, respectively. These results pave the way to study cyclic and non-cyclic reactions and represent a new field of time-resolved structural dynamics for numerous substrate-triggered biological reactions.

  11. Design of an x-ray free electron laser undulator

    SciTech Connect

    Carr, R.

    1997-09-01

    An undulator designed to be used for an x-ray free electron laser has to meet a set of stringent requirements. With no optical cavity, an x-ray FeL operates in the single pass Self Amplified Spontaneous Emission (SASE) mode; an electron macropulse is microbunched by an undulator and the radiation it creates. The microbunched pulse emits spontaneous radiation and coherent FEL radiation, whose power may reach saturation in a sufficiently long and perfect undulator. The pulse must have low emittance and high current, and its trajectory in the undulator must keep the radiation and the pulse together with a very high degree of overlap. The authors shall consider the case of the Linear Coherent Light Source (LCLS) FEL project at SLAC, which is intended to create 1.5 {angstrom} x-rays using an electron beam with 15 GeV energy, 1.5{pi} mm-mrad normalized emittance, 3,400 A peak current, and 280 fsec FWHM bunch duration. They find that this 65 {micro}m rms diameter beam must overlap its radiation with a walk/off of no more than 5 {micro}m for efficient gain. This places severe limitations on the magnetic field errors and other mechanical tolerances. The following is a discussion of the undulator design, specifications, alignment, engineering, and beam position monitoring they plan to implement for the LCLS X-ray FEL.

  12. LIPSS Free-Electron Laser Searches for Dark Matter

    SciTech Connect

    Afanaciev, Andrei; Beard, Kevin; Biallas, George; Boyce, James R; Minarni, M; Ramdon, R; Robinson, Taylor; Shinn, Michelle D; Slocum, P

    2011-09-01

    A variety of Dark Matter particle candidates have been hypothesized by physics Beyond the Standard Model (BSM) in the very light (10{sup -6} - 10{sup -3} eV) range. In the past decade several international groups have conducted laboratory experiments designed to either produce such particles or extend the boundaries in parameter space. The LIght Pseudo-scalar and Scalar Search (LIPSS) Collaboration, using the 'Light Shining through a Wall' (LSW) technique, passes the high average power photon beam from Jefferson Lab's Free-Electron Laser through a magnetic field upstream from a mirror and optical beam dump. Light Neutral Bosons (LNBs), generated by coupling of photons with the magnetic field, pass through the mirror ('the Wall') into an identical magnetic field where they revert to detectable photons by the same coupling process. While no evidence of LNBs was evident, new scalar coupling boundaries were established. New constraints were also determined for hypothetical para-photons and for millicharged fermions. We will describe our experimental setup and results for LNBs, para-photons, and milli-charged fermions. Plans for chameleon particle searches are underway.

  13. Efficiency enhancement of a harmonic lasing free-electron laser

    SciTech Connect

    Salehi, E.; Maraghechi, B.; Mirian, N. S.

    2015-03-15

    The harmonic lasing free-electron laser amplifier, in which two wigglers is employed in order for the fundamental resonance of the second wiggler to coincide with the third harmonic of the first wiggler to generate ultraviolet radiation, is studied. A set of coupled nonlinear first-order differential equations describing the nonlinear evolution of the system, for a long electron bunch, is solved numerically by CYRUS code. Solutions for the non-averaged and averaged equations are compared. Remarkable agreement is found between the averaged and non-averaged simulations for the evolution of the third harmonic. Thermal effects in the form of longitudinal velocity spread are also investigated. For efficiency enhancement, the second wiggler field is set to decrease linearly and nonlinearly at the point where the radiation of the third harmonic saturates. The optimum starting point and the slope of the tapering of the amplitude of the wiggler are found by a successive run of the code. It is found that tapering can increase the saturated power of the third harmonic considerably. In order to reduce the length of the wiggler, the prebunched electron beam is considered.

  14. Reflection of attosecond x-ray free electron laser pulses

    SciTech Connect

    Hau-Riege, S; Chapman, H

    2006-10-30

    In order to utilize hard x-ray free electron lasers (XFEL's) when they are extended to attosecond pulse lengths, it is necessary to choose optical elements with minimal response time. Specular grazing incidence optics made of low-Z materials are popular candidates for reflectors since they are likely to withstand x-ray damage and provide sufficiently large reflectivities. Using linear-optics reflection theory, we calculated the transient reflectivity of a delta-function electric pulse from a homogeneous semi-infinite medium as a function of angle of incidence for s- and p-polarized light. We specifically considered the pulse response of Be, diamond, silicon carbide, and silicon, all of which are of relevance to the XFEL's that are currently being built. We found that the media emit energy in a damped oscillatory way, and that the impulse-response times are shorter than 0.3 fs for normal incidence. For grazing incidence, the impulse-response time is substantially shorter, making grazing-incidence mirrors a good choice for deep-sub-femtosecond reflective optics.

  15. Reflection of attosecond x-ray free electron laser pulses

    SciTech Connect

    Hau-Riege, Stefan P.; Chapman, Henry N.

    2007-01-15

    In order to utilize hard x-ray free electron lasers (XFEL's) when they are extended to attosecond pulse lengths, it is necessary to choose optical elements with minimal response time. Specular grazing-incidence optics made of low-Z materials are popular candidates for reflectors since they are likely to withstand x-ray damage and provide sufficiently large reflectivities. Using linear-optics reflection theory, we calculated the transient reflectivity of a delta-function electric pulse from a homogenous semi-infinite medium as a function of angle of incidence for s- and p-polarized light. We specifically considered the pulse response of beryllium, diamond, silicon carbide, and silicon, all of which are of relevance to the XFEL's that are currently being built. We found that the media emit energy in a damped oscillatory way, and that the impulse-response times are shorter than 0.3 fs for normal incidence. For grazing incidence, the impulse-response time is substantially shorter, making grazing-incidence mirrors a good choice for deep subfemtosecond reflective optics.

  16. LIPSS Free-Electron Laser Searches for Dark Matter

    NASA Astrophysics Data System (ADS)

    Boyce, J. R.; Afanasev, A.; Baker, O. K.; Beard, K. B.; Biallas, G.; Minarni, M.; Ramdon, R.; Robinson, T.; Shinn, M.; Slocum, P.

    2011-08-01

    A variety of Dark Matter particle candidates have been hypothesized by physics Beyond the Standard Model (BSM) in the very light (10-6 - 10-3 eV) range. In the past decade several international groups have conducted laboratory experiments designed to either produce such particles or extend the boundaries in parameter space. The LIght Pseudo-scalar and Scalar Search (LIPSS) Collaboration, using the "Light Shining through a Wall" (LSW) technique, pass the high average power photon beam from Jefferson Lab's Free-Electron Laser through a magnetic field upstream from a mirror and optical beam dump. Light Neutral Bosons (LNBs), generated by coupling of photons with the magnetic field, pass through the mirror ("the Wall") into an identical magnetic field where they revert to detectable photons by the same coupling process. While no evidence of LNBs was evident, new scalar coupling boundaries were established. New constraints were also determined for hypothetical para-photons and for millicharged fermions. We describe our experimental setup and results for LNBs, para-photons, and milli-charged fermions. Plans for chameleon particle searches are underway

  17. Dark Matter Searches using a Free-Electron Laser (FEL)

    NASA Astrophysics Data System (ADS)

    Boyce, James R.; Afanasev, A.; Baker, O. K.; Beard, K. B.; Biallas, G.; Minarni, M.; Ramdon, R.; Shinn, M.; Slocum, P.

    2009-05-01

    Photon coupling to light neutral bosons in the meV mass range has been predicted and searched for by several international collaborations. Using the ``light shining through a wall'' technique, light from Jefferson Lab's high average power Free-Electron Laser (FEL) was passed through a strong magnetic field upstream of an optical beam dump; regenerated photons were then searched for downstream of a second magnetic field region optically shielded from the former. While our initial results show no evidence for scalar coupling in this region of parameter space, the results establish new coupling boundaries. New constraints on the hypothetical para-photon particles were also obtained. We describe the experimental setup, the initial scalar boson results, and proposed experiments that include searching for para-photons and chameleon particles. Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce this manuscript for U.S. Government purposes.

  18. Structural enzymology using X-ray free electron lasers

    DOE PAGES

    Kupitz, Christopher; Olmos, Jose L.; Holl, Mark; ...

    2017-07-01

    Mix-and-inject serial crystallography (MISC) is a technique designed to image enzyme catalyzed reactions in which small protein crystals are mixed with a substrate just prior to being probed by an X-ray pulse. This approach offers several advantages over flow cell studies. It provides (i) room temperature structures at near atomic resolution, (ii) time resolution ranging from microseconds to seconds, and (iii) convenient reaction initiation. It outruns radiation damage by using femtosecond X-ray pulses allowing damage and chemistry to be separated. Here, we demonstrate that MISC is feasible at an X-ray free electron laser by studying the reaction of M. tuberculosismore » ß-lactamase microcrystals with ceftriaxone antibiotic solution. Electron density maps of the apo-ß-lactamase and of the ceftriaxone bound form were obtained at 2.8 Å and 2.4 Å resolution, respectively. Finally, these results pave the way to study cyclic and non-cyclic reactions and represent a new field of time-resolved structural dynamics for numerous substrate-triggered biological reactions.« less

  19. Low emittance injector design for free electron lasers

    NASA Astrophysics Data System (ADS)

    Bettoni, S.; Pedrozzi, M.; Reiche, S.

    2015-12-01

    Several parameters determine the performance of free electron lasers: the slice and the projected emittance, the slice energy spread, and the peak current are the most crucial ones. The peak current is essentially obtained by magnetic compression stages along the machine or occasionally assisted by velocity bunching at low energy. The minimum emittance and the alignment of the slices along the bunch are mainly determined in the low energy part of the accelerator (injector). Variations at the per-mille level of several parameters in this section of the machine strongly influence these quantities with highly nonlinear dynamic. We developed a numerical tool to perform the optimization of the injector. We applied this code to optimize the SwissFEL injector, assuming different gun designs, initial bunch lengths and intrinsic emittances. We obtained an emittance along the bunch of 0.14 mm mrad and around 0.08 mm mrad for the maximum and the minimum SwissFEL charges (200 and 10 pC, respectively). We applied the same tool to a running injector, where we automatized the optimization of the machine.

  20. Novel resonators for Smith-Purcell free-electron lasers

    NASA Astrophysics Data System (ADS)

    Platt, Christopher L.

    1997-09-01

    A Smith-Purcell Free Electron Laser test-facility has been developed. The structure is used to conduct detailed explorations that novel resonator designs will have on tunability, start current and other performance criteria. Emphasis is on sources which operate at millimeter wavelengths and utilize moderate energy electron beams. The Smith-Purcell radiation is produced by passing a 3-15 kV, submillimeter diameter electron beam over a metal grating with a rectangular profile. Radiation is produced at 35-40 GHz, 75 GHz and 95-100 GHz using different gratings. Three resonator configurations have been investigated. Two are planar orotron designs with different quality factors. Starting currents as low as 1 to 10 mA have been observed in the 35-40 GHz range. A third configuration is a bare grating without an external feedback elements. Performance was equal or superior to the original planar orotron designs. Radiation from this structure is observed by looking for bound modes launched in the backward direction. Starting currents of 15 mA are observed and the wavelength is continuously tunable. This design is simpler and more robust and allows a better understanding of the operation of the device.

  1. Extreme-Ultraviolet Vortices from a Free-Electron Laser

    NASA Astrophysics Data System (ADS)

    Rebernik Ribič, Primož; Rösner, Benedikt; Gauthier, David; Allaria, Enrico; Döring, Florian; Foglia, Laura; Giannessi, Luca; Mahne, Nicola; Manfredda, Michele; Masciovecchio, Claudio; Mincigrucci, Riccardo; Mirian, Najmeh; Principi, Emiliano; Roussel, Eléonore; Simoncig, Alberto; Spampinati, Simone; David, Christian; De Ninno, Giovanni

    2017-07-01

    Extreme-ultraviolet vortices may be exploited to steer the magnetic properties of nanoparticles, increase the resolution in microscopy, and gain insight into local symmetry and chirality of a material; they might even be used to increase the bandwidth in long-distance space communications. However, in contrast to the generation of vortex beams in the infrared and visible spectral regions, production of intense, extreme-ultraviolet and x-ray optical vortices still remains a challenge. Here, we present an in-situ and an ex-situ technique for generating intense, femtosecond, coherent optical vortices at a free-electron laser in the extreme ultraviolet. The first method takes advantage of nonlinear harmonic generation in a helical undulator, producing vortex beams at the second harmonic without the need for additional optical elements, while the latter one relies on the use of a spiral zone plate to generate a focused, micron-size optical vortex with a peak intensity approaching 1014 W /cm2 , paving the way to nonlinear optical experiments with vortex beams at short wavelengths.

  2. Photothermal effect for arteriosclerotic region using infrared free electron lasers

    NASA Astrophysics Data System (ADS)

    Awazu, Kunio; Fukami, Yuko

    1999-09-01

    Cholesteryl oleate can be selectively removed with an infrared free-electron laser (IFEL). To determine the mechanisms that are involved in the effects induced by IFEL, we compared the effect of FEL exposure and the effect of heating on a sample film and bulk sample of cholesteryl oleate. Heating is regarded as one of the mechanisms by which FEL ablates cholesteryl oleate that has accumulated on the arteriosclerotic region of arterial walls. FEL was applied at a wavelength of 5.75 micrometers and at several average powers (2 - 15 mW). FEL exposure induced melting and a decrease in the number of ester bonds. Using the value of absorbed IFEL- macropulse energy for each power density, the temperature was assumed to be 50 - 300 degree(s)C. In the heating experiment, the sample was heated from room temperature to 500 degree(s)C. Melting and carbonization were observed at 50 degree(s)C and 300 degree(s)C, respectively. We found that FEL exposure and heating each induced melting. FEL exposure induced chemical changes and ablation of cholesteryl oleate, although heating did not. Heating the cholesteryl oleate above 305 degree(s)C induced carbonization, although FEL exposure to the same temperature did not.

  3. Modeling and multidimensional optimization of a tapered free electron laser

    NASA Astrophysics Data System (ADS)

    Jiao, Y.; Wu, J.; Cai, Y.; Chao, A. W.; Fawley, W. M.; Frisch, J.; Huang, Z.; Nuhn, H.-D.; Pellegrini, C.; Reiche, S.

    2012-05-01

    Energy extraction efficiency of a free electron laser (FEL) can be greatly increased using a tapered undulator and self-seeding. However, the extraction rate is limited by various effects that eventually lead to saturation of the peak intensity and power. To better understand these effects, we develop a model extending the Kroll-Morton-Rosenbluth, one-dimensional theory to include the physics of diffraction, optical guiding, and radially resolved particle trapping. The predictions of the model agree well with that of the GENESIS single-frequency numerical simulations. In particular, we discuss the evolution of the electron-radiation interaction along the tapered undulator and show that the decreasing of refractive guiding is the major cause of the efficiency reduction, particle detrapping, and then saturation of the radiation power. With this understanding, we develop a multidimensional optimization scheme based on GENESIS simulations to increase the energy extraction efficiency via an improved taper profile and variation in electron beam radius. We present optimization results for hard x-ray tapered FELs, and the dependence of the maximum extractable radiation power on various parameters of the initial electron beam, radiation field, and the undulator system. We also study the effect of the sideband growth in a tapered FEL. Such growth induces increased particle detrapping and thus decreased refractive guiding that together strongly limit the overall energy extraction efficiency.

  4. Model-based optimization of tapered free-electron lasers

    NASA Astrophysics Data System (ADS)

    Mak, Alan; Curbis, Francesca; Werin, Sverker

    2015-04-01

    The energy extraction efficiency is a figure of merit for a free-electron laser (FEL). It can be enhanced by the technique of undulator tapering, which enables the sustained growth of radiation power beyond the initial saturation point. In the development of a single-pass x-ray FEL, it is important to exploit the full potential of this technique and optimize the taper profile aw(z ). Our approach to the optimization is based on the theoretical model by Kroll, Morton, and Rosenbluth, whereby the taper profile aw(z ) is not a predetermined function (such as linear or exponential) but is determined by the physics of a resonant particle. For further enhancement of the energy extraction efficiency, we propose a modification to the model, which involves manipulations of the resonant particle's phase. Using the numerical simulation code GENESIS, we apply our model-based optimization methods to a case of the future FEL at the MAX IV Laboratory (Lund, Sweden), as well as a case of the LCLS-II facility (Stanford, USA).

  5. The History of X-ray Free-Electron Lasers

    SciTech Connect

    Pellegrini, C.; /UCLA /SLAC

    2012-06-28

    The successful lasing at the SLAC National Accelerator Laboratory of the Linear Coherent Light Source (LCLS), the first X-ray free-electron laser (X-ray FEL), in the wavelength range 1.5 to 15 {angstrom}, pulse duration of 60 to few femtoseconds, number of coherent photons per pulse from 10{sup 13} to 10{sup 11}, is a landmark event in the development of coherent electromagnetic radiation sources. Until now electrons traversing an undulator magnet in a synchrotron radiation storage ring provided the best X-ray sources. The LCLS has set a new standard, with a peak X-ray brightness higher by ten orders of magnitudes and pulse duration shorter by three orders of magnitudes. LCLS opens a new window in the exploration of matter at the atomic and molecular scales of length and time. Taking a motion picture of chemical processes in a few femtoseconds or less, unraveling the structure and dynamics of complex molecular systems, like proteins, are some of the exciting experiments made possible by LCLS and the other X-ray FELs now being built in Europe and Asia. In this paper, we describe the history of the many theoretical, experimental and technological discoveries and innovations, starting from the 1960s and 1970s, leading to the development of LCLS.

  6. Optical properties of the output of a high gain, self-amplified free-electron laser.

    SciTech Connect

    Krinsky, S.; Lewellen , J.; Sajaev, V.; Accelerator Systems Division; BNL

    2004-01-01

    The temporal structure and phase evolutions of a high-gain, self-amplified free-electron laser are measured, including single-shot analysis and statistics over many shots. Excellent agreement with the theory of free-electron laser and photon statistics is found.

  7. Material Processing Opportunites Utilizing a Free Electron Laser

    NASA Astrophysics Data System (ADS)

    Todd, Alan

    1996-11-01

    Many properties of photocathode-driven Free Electron Lasers (FEL) are extremely attractive for material processing applications. These include: 1) broad-band tunability across the IR and UV spectra which permits wavelength optimization, depth deposition control and utilization of resonance phenomena; 2) picosecond pulse structure with continuous nanosecond spacing for optimum deposition efficiency and minimal collateral damage; 3) high peak and average radiated power for economic processing in quantity; and 4) high brightness for spatially defined energy deposition and intense energy density in small spots. We discuss five areas: polymer, metal and electronic material processing, micromachining and defense applications; where IR or UV material processing will find application if the economics is favorable. Specific examples in the IR and UV, such as surface texturing of polymers for improved look and feel, and anti-microbial food packaging films, which have been demonstrated using UV excimer lamps and lasers, will be given. Unfortunately, although the process utility is readily proven, the power levels and costs of lamps and lasers do not scale to production margins. However, from these examples, application specific cost targets ranging from 0.1=A2/kJ to 10=A2/kJ of delivered radiation at power levels from 10 kW to 500 kW, have been developed and are used to define strawman FEL processing systems. Since =46EL radiation energy extraction from the generating electron beam is typically a few percent, at these high average power levels, economic considerations dictate the use of a superconducting RF accelerator with energy recovery to minimize cavity and beam dump power loss. Such a 1 kW IR FEL, funded by the US Navy, is presently under construction at the Thomas Jefferson National Accelerator Facility. This dual-use device, scheduled to generate first light in late 1997, will test both the viability of high-power FELs for shipboard self-defense against cruise

  8. Novosibirsk Free Electron Laser: Recent Achievements and Future Prospects

    NASA Astrophysics Data System (ADS)

    Shevchenko, O. A.; Arbuzov, V. S.; Vinokurov, N. A.; Vobly, P. D.; Volkov, V. N.; Getmanov, Ya. V.; Davidyuk, I. V.; Deychuly, O. I.; Dementyev, E. N.; Dovzhenko, B. A.; Knyazev, B. A.; Kolobanov, E. I.; Kondakov, A. A.; Kozak, V. R.; Kozyrev, E. V.; Kubarev, V. V.; Kulipanov, G. N.; Kuper, E. A.; Kuptsov, I. V.; Kurkin, G. Ya.; Krutikhin, S. A.; Medvedev, L. E.; Motygin, S. V.; Ovchar, V. K.; Osipov, V. N.; Petrov, V. M.; Pilan, A. M.; Popik, V. M.; Repkov, V. V.; Salikova, T. V.; Sedlyarov, I. K.; Serednyakov, S. S.; Skrinsky, A. N.; Tararyshkin, S. V.; Tribendis, A. G.; Cheskidov, V. G.; Chernov, K. N.; Shcheglov, M. A.

    2017-02-01

    Free electron lasers (FELs) are unique sources of electromagnetic radiation with tunable wavelength. A high-power FEL has been created at the G. I.Budker Institute for Nuclear Physics. Its radiation frequency can be tuned over a wide range in the terahertz and infrared spectral ranges. As the source of electron bunches, this FEL uses a multi-turn energy-recovery linac, which has five straight sections. Three sections are used for three FELs which operate in different wavelength ranges (90-240 μm for the first, 37-80 μm for the second, and 5-20 μm for the third ones). The first and the second FELs were commissioned in 2003 and 2009, respectively. They are used for various applied and research problems now. The third FEL is installed on the last, forth accelerator loop, in which the electron energy is the maximum. It comprises three undulator sections and a 40 m optical cavity. The first lasing of this FEL was obtained in the summer of 2015. The radiation wavelength was 9 μm and the average power was about 100 W. The design power is 1 kW at a pulse repetition rate of 3.75 MHz. Radiation of the third FEL will be delivered to user stations from the protected hall in the near future. The third FEL commissioning results are presented and the current status of the first and second FELs as well as their future development prospects are described.

  9. Design and experimental tests of free electron laser wire scanners

    NASA Astrophysics Data System (ADS)

    Orlandi, G. L.; Heimgartner, P.; Ischebeck, R.; Loch, C. Ozkan; Trovati, S.; Valitutti, P.; Schlott, V.; Ferianis, M.; Penco, G.

    2016-09-01

    SwissFEL is a x-rays free electron laser (FEL) driven by a 5.8 GeV linac under construction at Paul Scherrer Institut. In SwissFEL, wire scanners (WSCs) will be complementary to view-screens for emittance measurements and routinely used to monitor the transverse profile of the electron beam during FEL operations. The SwissFEL WSC is composed of an in-vacuum beam-probe—motorized by a stepper motor—and an out-vacuum pick-up of the wire signal. The mechanical stability of the WSC in-vacuum hardware has been characterized on a test bench. In particular, the motor induced vibrations of the wire have been measured and mapped for different motor speeds. Electron-beam tests of the entire WSC setup together with different wire materials have been carried out at the 250 MeV SwissFEL Injector Test Facility (SITF, Paul Scherrer Institut, CH) and at FERMI (Elettra-Sincrotrone Trieste, Italy). In particular, a comparative study of the relative measurement accuracy and the radiation-dose release of Al (99 )∶Si (1 ) and tungsten (W) wires has been carried out. On the basis of the outcome of the bench and electron-beam tests, the SwissFEL WSC can be qualified as a high resolution and machine-saving diagnostic tool in consideration of the mechanical stability of the scanning wire at the micrometer level and the choice of the wire material ensuring a drastic reduction of the radiation-dose release with respect to conventional metallic wires. The main aspects of the design, laboratory characterization and electron beam tests of the SwissFEL WSCs are presented.

  10. Microwave axial free-electron laser with enhanced phase stability

    SciTech Connect

    Carlsten, B.; Fazio, M.; Haynes, W.

    1995-12-31

    Free-electron laser (FEL) amplifiers have demonstrated high efficiencies and high output power at microwave wavelengths. However, measurements and simulations have indicated that the present level of phase stability for these devices is not sufficient for driving linear accelerators. Fluctuations in the diode voltage, which is needed to accelerate the electron beam, are the largest cause of the shifts in the phase of the output power. Pulse-power technology cannot keep the voltage fluctuations less than 1/4%. However, we have found a scheme that will make the output phase much less sensitive to these fluctuations by exploiting the traveling wave nature of the FEL interaction. In this paper we study the phase stability issue by analyzing the dispersion relation for an axial FEL, in which the rf field is transversely wiggled and the electron trajectories are purely longitudinal. The advantage of using the axial FEL interaction instead of the common transverse FEL interaction is that (1) the dispersion relation is not additionally complicated by how the transverse electron motion depends on the diode voltage and (2) such a device is simpler and less expensive to construct than a transverse-coupling FEL because there is no wiggler. The axial FEL interaction is with a fast wave and does involve axial bunching of the electron beam, so the results found for this device also apply to transverse-coupling FELs. By examination of the dispersion relation it is found that the effect of the phase dependency on the beam`s velocity can be cancelled by the effect of the phase dependency on the beam`s plasma wave, for an annular electron beam. By changing the annulus radius, exact cancellation can be found for a variety of beam voltages and currents in the ranges of 0.5-1.0 MV and 1-5 kA. This cancellation leads to first-order phase stability, which is not possible for standing-wave devices, such as klystrons.

  11. Novosibirsk Free Electron Laser: Recent Achievements and Future Prospects

    NASA Astrophysics Data System (ADS)

    Shevchenko, O. A.; Arbuzov, V. S.; Vinokurov, N. A.; Vobly, P. D.; Volkov, V. N.; Getmanov, Ya. V.; Davidyuk, I. V.; Deychuly, O. I.; Dementyev, E. N.; Dovzhenko, B. A.; Knyazev, B. A.; Kolobanov, E. I.; Kondakov, A. A.; Kozak, V. R.; Kozyrev, E. V.; Kubarev, V. V.; Kulipanov, G. N.; Kuper, E. A.; Kuptsov, I. V.; Kurkin, G. Ya.; Krutikhin, S. A.; Medvedev, L. E.; Motygin, S. V.; Ovchar, V. K.; Osipov, V. N.; Petrov, V. M.; Pilan, A. M.; Popik, V. M.; Repkov, V. V.; Salikova, T. V.; Sedlyarov, I. K.; Serednyakov, S. S.; Skrinsky, A. N.; Tararyshkin, S. V.; Tribendis, A. G.; Cheskidov, V. G.; Chernov, K. N.; Shcheglov, M. A.

    2017-01-01

    Free electron lasers (FELs) are unique sources of electromagnetic radiation with tunable wavelength. A high-power FEL has been created at the G. I.Budker Institute for Nuclear Physics. Its radiation frequency can be tuned over a wide range in the terahertz and infrared spectral ranges. As the source of electron bunches, this FEL uses a multi-turn energy-recovery linac, which has five straight sections. Three sections are used for three FELs which operate in different wavelength ranges (90-240 μm for the first, 37-80 μm for the second, and 5-20 μm for the third ones). The first and the second FELs were commissioned in 2003 and 2009, respectively. They are used for various applied and research problems now. The third FEL is installed on the last, forth accelerator loop, in which the electron energy is the maximum. It comprises three undulator sections and a 40 m optical cavity. The first lasing of this FEL was obtained in the summer of 2015. The radiation wavelength was 9 μm and the average power was about 100 W. The design power is 1 kW at a pulse repetition rate of 3.75 MHz. Radiation of the third FEL will be delivered to user stations from the protected hall in the near future. The third FEL commissioning results are presented and the current status of the first and second FELs as well as their future development prospects are described.

  12. Analysis of Smith-Purcell free-electron lasers

    SciTech Connect

    Kumar, Vinit; Kim, Kwang-Je

    2006-02-15

    We present an analysis of the beam dynamics in a Smith-Purcell free-electron laser (FEL). In this system, an electron beam interacts resonantly with a copropagating surface electromagnetic mode near the grating surface. The surface mode arises as a singularity in the frequency dependence of the reflection matrix. Since the surface mode is confined very close to the grating surface, the interaction is significant only if the electrons are moving very close to the grating surface. The group velocity of the surface mode resonantly interacting with a low-energy electron beam is in the direction opposite to the electron beam. The Smith-Purcell FEL is therefore a backward wave oscillator in which, if the beam current exceeds a certain threshold known as start current, the optical intensity grows to saturation even if no mirrors are employed for feedback. We derive the coupled Maxwell-Lorentz equations for describing the interaction between the surface mode and the electron beam, starting from the slowly varying approximation and the singularity in the reflection matrix. In the linear regime, we derive an analytic expression for the start current and calculate the growth rate of optical power in time. The analysis is extended to the nonlinear regime by performing a one-dimensional time-dependent numerical simulation. Results of our numerical calculation compare well with the analytic calculation in the linear regime and show saturation behavior in the nonlinear regime. We find that a significant amount of power grows in the surface mode due to this interaction. Several ways to outcouple this power to freely propagating modes are discussed.

  13. Analysis of Smith-Purcell free-electron lasers

    NASA Astrophysics Data System (ADS)

    Kumar, Vinit; Kim, Kwang-Je

    2006-02-01

    We present an analysis of the beam dynamics in a Smith-Purcell free-electron laser (FEL). In this system, an electron beam interacts resonantly with a copropagating surface electromagnetic mode near the grating surface. The surface mode arises as a singularity in the frequency dependence of the reflection matrix. Since the surface mode is confined very close to the grating surface, the interaction is significant only if the electrons are moving very close to the grating surface. The group velocity of the surface mode resonantly interacting with a low-energy electron beam is in the direction opposite to the electron beam. The Smith-Purcell FEL is therefore a backward wave oscillator in which, if the beam current exceeds a certain threshold known as start current, the optical intensity grows to saturation even if no mirrors are employed for feedback. We derive the coupled Maxwell-Lorentz equations for describing the interaction between the surface mode and the electron beam, starting from the slowly varying approximation and the singularity in the reflection matrix. In the linear regime, we derive an analytic expression for the start current and calculate the growth rate of optical power in time. The analysis is extended to the nonlinear regime by performing a one-dimensional time-dependent numerical simulation. Results of our numerical calculation compare well with the analytic calculation in the linear regime and show saturation behavior in the nonlinear regime. We find that a significant amount of power grows in the surface mode due to this interaction. Several ways to outcouple this power to freely propagating modes are discussed.

  14. Analysis of Smith-Purcell free-electron lasers.

    PubMed

    Kumar, Vinit; Kim, Kwang-Je

    2006-02-01

    We present an analysis of the beam dynamics in a Smith-Purcell free-electron laser (FEL). In this system, an electron beam interacts resonantly with a copropagating surface electromagnetic mode near the grating surface. The surface mode arises as a singularity in the frequency dependence of the reflection matrix. Since the surface mode is confined very close to the grating surface, the interaction is significant only if the electrons are moving very close to the grating surface. The group velocity of the surface mode resonantly interacting with a low-energy electron beam is in the direction opposite to the electron beam. The Smith-Purcell FEL is therefore a backward wave oscillator in which, if the beam current exceeds a certain threshold known as start current, the optical intensity grows to saturation even if no mirrors are employed for feedback. We derive the coupled Maxwell-Lorentz equations for describing the interaction between the surface mode and the electron beam, starting from the slowly varying approximation and the singularity in the reflection matrix. In the linear regime, we derive an analytic expression for the start current and calculate the growth rate of optical power in time. The analysis is extended to the nonlinear regime by performing a one-dimensional time-dependent numerical simulation. Results of our numerical calculation compare well with the analytic calculation in the linear regime and show saturation behavior in the nonlinear regime. We find that a significant amount of power grows in the surface mode due to this interaction. Several ways to outcouple this power to freely propagating modes are discussed.

  15. Induction-linac based free-electron laser amplifiers for plasma heating

    SciTech Connect

    Jong, R.A.

    1988-08-22

    We describe an induction-linac based free-electron laser amplifier that is presently under construction at the Lawrence Livermore National Laboratory. It is designed to produce up to 2 MW of average power at a frequency of 250 GHz for plasma heating experiments in the Microwave Tokamak Experiment. In addition, we shall describe a FEL amplifier design for plasma heating of advanced tokamak fusion devices. This system is designed to produce average power levels of about 10 MW at frequencies ranging form 280 to 560 GHz. 7 refs., 1 tab.

  16. Induction-linac based free-electron laser amplifiers for plasma heating

    NASA Astrophysics Data System (ADS)

    Jong, R. A.

    1988-08-01

    We describe an induction-linac based free-electron laser amplifier that is presently under construction at the Lawrence Livermore National Laboratory. It is designed to produce up to 2 MW of average power at a frequency of 250 GHz for plasma heating experiments in the Microwave Tokamak Experiment. In addition, we shall describe a FEL amplifier design for plasma heating of advanced tokamak fusion devices. This system is designed to produce average power levels of about 10 MW at frequencies ranging from 280 to 560 GHz.

  17. Coherent-pulse 2D crystallography using a free-electron laser x-ray source.

    PubMed

    Mancuso, A P; Schropp, A; Reime, B; Stadler, L-M; Singer, A; Gulden, J; Streit-Nierobisch, S; Gutt, C; Grübel, G; Feldhaus, J; Staier, F; Barth, R; Rosenhahn, A; Grunze, M; Nisius, T; Wilhein, T; Stickler, D; Stillrich, H; Frömter, R; Oepen, H-P; Martins, M; Pfau, B; Günther, C M; Könnecke, R; Eisebitt, S; Faatz, B; Guerassimova, N; Honkavaara, K; Kocharyan, V; Treusch, R; Saldin, E; Schreiber, S; Schneidmiller, E A; Yurkov, M V; Weckert, E; Vartanyants, I A

    2009-01-23

    Coherent diffractive imaging for the reconstruction of a two-dimensional (2D) finite crystal structure with a single pulse train of free-electron laser radiation at 7.97 nm wavelength is demonstrated. This measurement shows an advance on traditional coherent imaging techniques by applying it to a periodic structure. It is also significant that this approach paves the way for the imaging of the class of specimens which readily form 2D, but not three-dimensional crystals. We show that the structure is reconstructed to the detected resolution, given an adequate signal-to-noise ratio.

  18. Pair annihilation in laser pulses: Optical versus x-ray free-electron laser regimes

    SciTech Connect

    Ilderton, Anton; Johansson, Petter; Marklund, Mattias

    2011-09-15

    We discuss the theory and phenomenology of pair annihilation, within an ultrashort laser pulse, to a single photon. The signature of this process is the unidirectional emission of single photons with a fixed energy. We show that the cross section is significantly larger than for two-photon pair annihilation in vacuum, with x-ray free-electron laser parameters admitting a much clearer signal than optical beams.

  19. Ultraviolet laser transverse profile shaping for improving x-ray free electron laser performance

    DOE PAGES

    Li, S.; Alverson, S.; Bohler, D.; ...

    2017-08-17

    The photocathode rf gun is one of the most critical components in x-ray free electron lasers. The drive laser strikes the photocathode surface, which emits electrons with properties that depend on the shape of the drive laser. Most free electron lasers use photocathodes with work function in the ultraviolet, a wavelength where direct laser manipulation becomes challenging. In this paper, we present a novel application of a digital micromirror device (DMD) for the 253 nm drive laser at the Linear Coherent Light Source. Laser profile shaping is accomplished through an iterative algorithm that takes into account shaping error and efficiency.more » Next, we use laser shaping to control the X-ray laser output via an online optimizer, which shows improvement in FEL pulse energy. Lastly, as a preparation for electron beam shaping, we use the DMD to measure the photocathode quantum efficiency across cathode surface with an averaged laser rms spot size of 59 μm. In conclusion, our experiments demonstrate promising outlook of using DMD to shape ultraviolet lasers for photocathode rf guns with various applications.« less

  20. Ultraviolet laser transverse profile shaping for improving x-ray free electron laser performance

    NASA Astrophysics Data System (ADS)

    Li, S.; Alverson, S.; Bohler, D.; Egger, A.; Fry, A.; Gilevich, S.; Huang, Z.; Miahnahri, A.; Ratner, D.; Robinson, J.; Zhou, F.

    2017-08-01

    The photocathode rf gun is one of the most critical components in x-ray free electron lasers. The drive laser strikes the photocathode surface, which emits electrons with properties that depend on the shape of the drive laser. Most free electron lasers use photocathodes with work function in the ultraviolet, a wavelength where direct laser manipulation becomes challenging. In this paper, we present a novel application of a digital micromirror device (DMD) for the 253 nm drive laser at the Linear Coherent Light Source. Laser profile shaping is accomplished through an iterative algorithm that takes into account shaping error and efficiency. Next, we use laser shaping to control the X-ray laser output via an online optimizer, which shows improvement in FEL pulse energy. Lastly, as a preparation for electron beam shaping, we use the DMD to measure the photocathode quantum efficiency across cathode surface with an averaged laser rms spot size of 59 μ m . Our experiments demonstrate promising outlook of using DMD to shape ultraviolet lasers for photocathode rf guns with various applications.

  1. Proposal for an x-ray free electron laser oscillator with intermediate energy electron beam.

    PubMed

    Dai, Jinhua; Deng, Haixiao; Dai, Zhimin

    2012-01-20

    Harmonic lasing of low-gain free electron laser oscillators has been experimentally demonstrated in the terahertz and infrared regions. Recently, the low-gain oscillator has been reconsidered as a promising candidate for hard x-ray free electron lasers, through the use of high reflectivity, high-resolution x-ray crystals. In this Letter, it is proposed to utilize a crystal-based cavity resonant at a higher harmonic of the undulator radiation, together with phase shifting, to enable harmonic lasing of the x-ray free electron laser oscillator, and hence allow the generation of hard x-ray radiation at a reduced electron beam energy. Results show that fully coherent free electron laser radiation with megawatt peak power, in the spectral region of 10-25 keV, can be generated with a 3.5 GeV electron beam.

  2. Proceedings of the workshop prospects for a 1 angstrom free-electron laser

    SciTech Connect

    Gallardo, J.C.

    1990-01-01

    This report contains papers on the following topics free-electron laser theory, scaling relations and simulations; micro-wigglers; photocathode and switched power gun; applications; and summary of working groups.

  3. Optimal Charge of a Photocathode Gun for a Compact X-ray Free-Electron Laser

    NASA Astrophysics Data System (ADS)

    Lee, Tae-Yeon; Chae, Moon Sik; Ko, In Soo

    2010-02-01

    For a photocathode gun, the optimal charge per gun pulse is derived to give the theoretically allowed smallest saturation length of the X-ray free-electron laser based on the self amplified spontaneous emission scheme. The derivation is approximate, but the result is practically independent of specific machine design. The objective is to contribute to the study of a compact X-ray free-electron laser.

  4. Applications of infrared free electron lasers in picosecond and nonlinear spectroscopy

    NASA Astrophysics Data System (ADS)

    Fann, W. S.; Benson, S. V.; Madey, J. M. J.; Etemad, S.; Baker, G. L.; Rothberg, L.; Roberson, M.; Austin, R. H.

    1990-10-01

    In this paper we describe two different types of spectroscopic experiments that exploit the characteristics of the infrared FEL, Mark III, for studies of condensed matter: - the spectrum of χ(3)(-3ω; ω, ω, ω) in polyacetylene: an application of the free electron laser in nonlinear optical spectroscopy, and - a dynamical test of Davydov-like solitons in acetanilide using a picosecond free electron laser. These two studies highlight the unique contributions FELs can make to condensed-matter spectroscopy.

  5. Energy Extraction from the Electron Beam in a Free Electron Laser Resonator Gaussian Mode.

    DTIC Science & Technology

    1983-01-01

    Elias, Juan Gallardo and Peter Goldstein N00014-80-C-0308 S. PF OR -ING ORGANIZATION NAME AND ADDRESS I . PROGRAM ELEMt.T PROJECT, TASK * ,’ niwxrsity...Elias, Juan Gallardo , Peter Goldstein Quantum Institue, University of California Santa Barbara, California 93106 ABSTRACT We present preliminary...QUANTUM INSTITUTE FREE ELECTRON LASER PROJECT Energy Extraction fran the Electron Beam in a Free Electron Laser Resonator Gaussian Mode Luis Elias, Juan

  6. Optimization of a Seeded Free-Electron Laser with Helical Undulators

    SciTech Connect

    Labat, M.; Hosaka, M.; Shimada, M.; Katoh, M.; Couprie, M. E.

    2008-10-17

    Seeded single pass free-electron lasers are promising coherent, short-duration, and intense light sources, from the visible to x rays. Operated with adjustable undulators, they are also a unique device for providing fully variable polarized radiation. We report here the first seeding of helical undulators with a variable polarized source. We demonstrate that the adjustment of the seed polarization and focusing allows the free-electron laser radiation to be optimized in terms of intensity and quality.

  7. Simulations of the high average power selene free electron laser prototype. Master's thesis

    SciTech Connect

    Quick, D.D.

    1994-06-01

    Free electron laser (FEL) technology continues to advance, providing alternative solutions to existing and potential problems. The capabilities of an FEL with respect to tunability, power and efficiency make it an attractive choice when moving into new laser utilization fields. The initial design parameters, for any new system, offer a good base to begin system simulation tests in an effort to determine the best possible design. This is a study of the Novosibirsk design which is a prototype for the proposed SELENE FEL. The design uses a three-section, low-power optical klystron followed by a single-pass, high-power radiator. This system is inherently sensitive to electron beam quality, but affords flexibility in achieving the final design. The performance of the system is studied using the initial parameters. An FEL, configured as a simple, two section optical klystron is studied to determine the basic operating characteristics of a high current FEL klystron.

  8. Evidence of high harmonics from echo-enabled harmonic generation for seeding x-ray free electron lasers.

    PubMed

    Xiang, D; Colby, E; Dunning, M; Gilevich, S; Hast, C; Jobe, K; McCormick, D; Nelson, J; Raubenheimer, T O; Soong, K; Stupakov, G; Szalata, Z; Walz, D; Weathersby, S; Woodley, M

    2012-01-13

    Echo-enabled harmonic generation free electron lasers hold great promise for the generation of fully coherent radiation in x-ray wavelengths. Here we report the first evidence of high harmonics from the echo-enabled harmonic generation technique in the realistic scenario where the laser energy modulation is comparable to the beam slice energy spread. In this experiment, coherent radiation at the seventh harmonic of the second seed laser is generated when the energy modulation amplitude is about 2-3 times the slice energy spread. The experiment confirms the underlying physics of echo-enabled harmonic generation and may have a strong impact on emerging seeded x-ray free electron lasers that are capable of generating laserlike x rays which will advance many areas of science.

  9. Evidence of High Harmonics from Echo-Enabled Harmonic Generation for Seeding X-ray Free Electron Lasers

    SciTech Connect

    Xiang, D.; Colby, E.; Dunning, M.; Gilevich, S.; Hast, C.; Jobe, K.; McCormick, D.; Nelson, J.; Raubenheimer, T.O.; Soong, K.; Stupakov, G.; Szalata, Z.; Walz, D.; Weathersby, S.; Woodle, M.; /SLAC

    2012-02-15

    Echo-enabled harmonic generation free electron lasers hold great promise for the generation of fully coherent radiation in x-ray wavelengths. Here we report the first evidence of high harmonics from the echo-enabled harmonic generation technique in the realistic scenario where the laser energy modulation is comparable to the beam slice energy spread. In this experiment, coherent radiation at the seventh harmonic of the second seed laser is generated when the energy modulation amplitude is about 2-3 times the slice energy spread. The experiment confirms the underlying physics of echo-enabled harmonic generation and may have a strong impact on emerging seeded x-ray free electron lasers that are capable of generating laserlike x rays which will advance many areas of science.

  10. Preparations for a high gradient inverse free electron laser experiment at Brookhaven national laboratory

    NASA Astrophysics Data System (ADS)

    Duris, J.; Li, R. K.; Musumeci, P.; Sakai, Y.; Threlkeld, E.; Williams, O.; Fedurin, M.; Kusche, K.; Pogorelsky, I.; Polyanskiy, M.; Yakimenko, V.

    2012-12-01

    Preparations for an inverse free electron laser experiment at Brookhaven National Laboratory's Accelerator Test Facilty are presented. Details of the experimental setup including beam and laser transport optics are first discussed. Next, the driving laser pulse structure is investigated and initial diagnostics are explored and compared to simulations. Finally, planned improvements to the experimental setup are discussed.

  11. The chirped-pulse inverse free-electron laser: A high-gradient vacuum laser accelerator

    NASA Astrophysics Data System (ADS)

    Hartemann, F. V.; Landahl, E. C.; Troha, A. L.; Van Meter, J. R.; Baldis, H. A.; Freeman, R. R.; Luhmann, N. C.; Song, L.; Kerman, A. K.; Yu, D. U. L.

    1999-10-01

    The inverse free-electron laser (IFEL) interaction is studied theoretically and computationally in the case where the drive laser intensity approaches the relativistic regime, and the pulse duration is only a few optical cycles long. The IFEL concept has been demonstrated as a viable vacuum laser acceleration process; it is shown here that by using an ultrashort, ultrahigh-intensity drive laser pulse, the IFEL interaction bandwidth and accelerating gradient are increased considerably, thus yielding large energy gains. Using a chirped pulse and negative dispersion focusing optics allows one to take further advantage of the laser optical bandwidth and produce a chromatic line focus maximizing the gradient. The combination of these novel ideas results in a compact vacuum laser accelerator capable of accelerating picosecond electron bunches with a high gradient (GeV/m) and very low energy spread.

  12. Density gradient free electron collisionally excited x-ray laser

    DOEpatents

    Campbell, E.M.; Rosen, M.D.

    1984-11-29

    An operational x-ray laser is provided that amplifies 3p-3s transition x-ray radiation along an approximately linear path. The x-ray laser is driven by a high power optical laser. The driving line focused optical laser beam illuminates a free-standing thin foil that may be associated with a substrate for improved structural integrity. This illumination produces a generally cylindrically shaped plasma having an essentially uniform electron density and temperature, that exists over a long period of time, and provides the x-ray laser gain medium. The x-ray laser may be driven by more than one optical laser beam. The x-ray laser has been successfully demonstrated to function in a series of experimental tests.

  13. Density gradient free electron collisionally excited X-ray laser

    DOEpatents

    Campbell, Edward M.; Rosen, Mordecai D.

    1989-01-01

    An operational X-ray laser (30) is provided that amplifies 3p-3s transition X-ray radiation along an approximately linear path. The X-ray laser (30) is driven by a high power optical laser. The driving line focused optical laser beam (32) illuminates a free-standing thin foil (34) that may be associated with a substrate (36) for improved structural integrity. This illumination produces a generally cylindrically shaped plasma having an essentially uniform electron density and temperature, that exists over a long period of time, and provides the X-ray laser gain medium. The X-ray laser (30) may be driven by more than one optical laser beam (32, 44). The X-ray laser (30) has been successfully demonstrated to function in a series of experimental tests.

  14. Efficiency enhancement using electron energy detuning in a laser seeded free electron laser amplifier

    SciTech Connect

    Wang, X. J.; Watanabe, T.; Shen, Y.; Li, R. K.; Murphy, J. B.; Tsang, T.; Freund, H. P.

    2007-10-29

    We report the experimental characterization of efficiency enhancement in a single-pass seeded free-electron laser (FEL) where the electron energy is detuned from resonance. Experiments show a doubling of the efficiency for beam energies above the resonant energy. Measurements of the FEL spectra versus energy detuning shows that the wavelength is governed by the seed laser. The variation in the gain length with beam energy was also observed. Good agreement is found between the experiment and numerical simulations using the MEDUSA simulation code.

  15. Chirped-Pulse Inverse Free Electron Laser: A Tabletop, High-Gradient Vacuum Laser Accelerator

    SciTech Connect

    Hartemann, F V; Troha, A L; Baldis, H A

    2001-03-05

    The inverse free-electron laser (IFEL) interaction is studied both theoretically and numerically in the case where the drive laser intensity approaches the relativistic regime, and the pulse duration is only a few optical cycles long. We show that by using an ultrashort, ultrahigh-intensity drive laser pulse, the IFEL interaction bandwidth and accelerating gradient are increased considerably, thus yielding large energy gains. Using a chirped pulse and negative dispersion focusing optics allows one to take further advantage of the laser optical bandwidth and produce a chromatic line focus maximizing the gradient. The combination of these novel ideas results in a compact vacuum laser accelerator capable of accelerating picosecond electron bunches with a high gradient (GeV/m) and very low energy spread. A computer code which takes into account the three-dimensional nature of the interaction is currently in development and results are expected this Spring.

  16. On the release of cppxfel for processing X-ray free-electron laser images

    DOE PAGES

    Ginn, Helen Mary; Evans, Gwyndaf; Sauter, Nicholas K.; ...

    2016-05-11

    As serial femtosecond crystallography expands towards a variety of delivery methods, including chip-based methods, and smaller collected data sets, the requirement to optimize the data analysis to produce maximum structure quality is becoming increasingly pressing. Herecppxfel, a software package primarily written in C++, which showcases several data analysis techniques, is released. This software package presently indexes images using DIALS (diffraction integration for advanced light sources) and performs an initial orientation matrix refinement, followed by post-refinement of individual images against a reference data set.Cppxfelis released with the hope that the unique and useful elements of this package can be repurposed formore » existing software packages. However, as released, it produces high-quality crystal structures and is therefore likely to be also useful to experienced users of X-ray free-electron laser (XFEL) software who wish to maximize the information extracted from a limited number of XFEL images.« less

  17. X-ray Free-Electron Lasers - Present and Future Capabilities [Invited

    SciTech Connect

    Galayda, John; Ratner, John Arthur:a Daniel F.; White, William E.; /SLAC

    2011-11-16

    The Linac Coherent Light Source is now in operation as an X-ray free-electron laser (FEL) user facility. It produces coherent pulses of 550-10,000 eV X-rays of duration adjustable from <10 fsto500 fs. Typical peak power is in excess of 20 GW. The facility will soon be joined by several X-ray FELs under construction around the world. This article will provide an abridged history of free-electron lasers, a description of some basic physics regarding free-electron laser light amplification, and an overview of the rapidly growing list of examples in which lasers will be used in the control and operation of X-ray FELs.

  18. X-ray free-electron lasers--present and future capabilities [Invited

    SciTech Connect

    Galayda, John N.; Arthur, John; Ratner, Daniel F.; White, William E.

    2010-11-15

    The Linac Coherent Light Source is now in operation as an X-ray free-electron laser (FEL) user facility. It produces coherent pulses of 550-10,000 eV X-rays of duration adjustable from <10 fs to 500 fs. Typical peak power is in excess of 20 GW. The facility will soon be joined by several X-ray FELs under construction around the world. This article will provide an abridged history of free-electron lasers, a description of some basic physics regarding free-electron laser light amplification, and an overview of the rapidly growing list of examples in which lasers will be used in the control and operation of X-ray FELs.

  19. Cultured human cornea healing process after free-electron-laser ablation

    NASA Astrophysics Data System (ADS)

    Shen, Jin-Hui; Joos, Karen M.; Shetlar, Debra J.; Robinson, Richard D.; Thind, Gurpreet K.; Edwards, Glenn S.; O'Day, Denis M.

    1997-05-01

    The purpose of this study is to investigate the healing process in cultured human cornea after infrared Free Electron Laser ablation. Fresh human cadaver cornea was ablated using the Free Electron Laser at the amide II band peak (6.45 micrometers ). The cornea was then cultured in an incubator for 18 days. Haze development within the ablated area was monitored during culture. Histologic sections of the cornea showed complete re-epithelialization of the lased area, and ablation of the underlying Bowman's layer and stroma. The endothelium appeared unaffected. Cultured human corneas may provide useful information regarding the healing process following laser ablation.

  20. An overview of the Lawrence Livermore National Laboratory Free Electron Laser Program

    SciTech Connect

    Shay, H.D.

    1986-12-18

    This paper reviews the status of the LLNL Free Electron Laser Program. Rather than using the output of an rf linac, the electron pulse from an induction linac enters the wiggler magnet without being bunched into small packets. The laser beam makes a single pass through the FEL amplifier. Wavelengths from several millimeters to less than 10/sup -6/m can be amplified. (JDH)

  1. Observation of Synchrotron Sidebands in a Storage-Ring-Based Seeded Free-Electron Laser

    SciTech Connect

    Labat, M.; Hosaka, M.; Yamamoto, N.; Shimada, M.; Katoh, M.; Couprie, M. E.

    2009-01-09

    Seeded free-electron lasers (FELs) are among the future fourth-generation light sources in the vacuum ultraviolet and x-ray spectral regions. We analyze the seed temporal coherence preservation in the case of coherent harmonic generation FELs, including spectral narrowing and structure degradation. Indeed, the electron synchrotron motion driven by the seeding laser can cause sideband growth in the FEL spectrum.

  2. Potential biophysical application of the Los Alamos infrared free electron laser: DNA spectroscopy

    NASA Astrophysics Data System (ADS)

    Lumpkin, Alex H.; Trewhella, Jill; Garcia, Angel E.

    1990-10-01

    Recently, the Los Alamos Free Electron Laser (FEL) has demonstrated optical output at wavelengths from 9 to 45 μm (1100 to 220 cm-1). Potential applications of such a laser are proposed for the study of vibrational modes predicted in different conformations of DNA and in DNA complexed with drugs and/or proteins that regulate replication and/or transcription.

  3. Free electron lasers driven by linear induction accelerators: High power radiation sources

    NASA Technical Reports Server (NTRS)

    Orzechowski, T. J.

    1989-01-01

    The technology of Free Electron Lasers (FELs) and linear induction accelerators (LIAs) is addressed by outlining the following topics: fundamentals of FELs; basic concepts of linear induction accelerators; the Electron Laser Facility (a microwave FEL); PALADIN (an infrared FEL); magnetic switching; IMP; and future directions (relativistic klystrons). This presentation is represented by viewgraphs only.

  4. Compton backscattering of intracavity storage ring free-electron laser radiation

    SciTech Connect

    Dattoli, G.; Giannessi, L.; Torre, A.

    1995-12-31

    We discuss the{gamma}-ray production by Compton backscattering of intracavity storage ring Free-Electron Laser radiation. We use a semi-analytical model which provides the build up of the signal combined with the storage ring damping mechanism and derive simple relations yielding the connection between backscattered. Photons brightness and the intercavity laser equilibrium intensity.

  5. Free-electron laser driven by the LBNL laser-plasma accelerator

    SciTech Connect

    Schroeder, C. B.; Fawley, W. M.; Robinson, K. E.; Toth, Cs.; Gruener, F.; Bakeman, M.; Nakamura, K.; Esarey, E.; Leemans, W. P.

    2009-01-22

    A design of a compact free-electron laser (FEL), generating ultra-fast, high-peak flux, XUV pulses is presented. The FEL is driven by a high-current, 0.5 GeV electron beam from the Lawrence Berkeley National Laboratory (LBNL) laser-plasma accelerator, whose active acceleration length is only a few centimeters. The proposed ultra-fast source ({approx}10 fs) would be intrinsically temporally synchronized to the drive laser pulse, enabling pump-probe studies in ultra-fast science. Owing to the high current (> or approx.10 kA) of the laser-plasma-accelerated electron beams, saturated output fluxes are potentially greater than 10{sup 13} photons/pulse. Devices based both on self-amplified spontaneous emission and high-harmonic generated input seeds, to reduce undulator length and fluctuations, are considered.

  6. Free-electron laser driven by the LBNL laser-plasma accelerator

    SciTech Connect

    Schroeder, C. B.; Fawley, W. M.; Gruner, F.; Bakeman, M.; Nakamura, K.; Robinson, K. E.; Toth, Cs.; Esarey, E.; Leemans, W. P.

    2008-08-04

    A design of a compact free-electron laser (FEL), generating ultra-fast, high-peak flux, XUV pulses is presented. The FEL is driven by ahigh-current, 0.5 GeV electron beam from the Lawrence Berkeley National Laboratory (LBNL) laser-plasma accelerator, whose active acceleration length is only a few centimeters. The proposed ultra-fast source (~;;10 fs) would be intrinsically temporally synchronized to the drive laser pulse, enabling pump-probe studies in ultra-fast science. Owing to the high current (>10 kA) of the laser-plasma-accelerated electron beams, saturated output fluxes are potentially greater than 10^13 photons/pulse. Devices based both on self-amplified spontaneous emission and high-harmonic generated input seeds, to reduce undulator length and fluctuations, are considered.

  7. Free Electron Laser Induced Forward Transfer Method of Biomaterial for Marking

    NASA Astrophysics Data System (ADS)

    Suzuki, Kaoru

    Biomaterial, such as chitosan, poly lactic acid, etc., containing fluorescence agent was deposited onto biology hard tissue, such as teeth, fingernail of dog or cat, or sapphire substrate by free electron laser induced forward transfer method for direct write marking. Spin-coated biomaterial with fluorescence agent of rhodamin-6G or zinc phthalochyamine target on sapphire plate was ablated by free electron laser (resonance absorption wavelength of biomaterial : 3380 nm). The influence of the spin-coating film-forming temperature on hardness and adhesion strength of biomaterial is particularly studied. Effect of resonance excitation of biomaterial target by turning free electron laser was discussed to damage of biomaterial, rhodamin-6G or zinc phtarochyamine for direct write marking

  8. Model for nonlinear behavior in the self-amplified spontaneous-emission free-electron laser.

    PubMed

    Krinsky, S

    2004-06-01

    We introduce a simplified model for the saturation of a self-amplified spontaneous-emission free-electron laser. Within this model, we determine the effect of nonlinearity upon the statistical properties of the output radiation. Comparing our results with the computer simulations of Saldin, Schneidmiller, and Yurkov [The Physics of Free Electron Lasers (Springer-Verlag, Berlin, 2000)], we find that the model provides a good description of the average intensity, field correlation function, and coherence time, but underestimates the intensity fluctuation. Asymmetric spectral broadening phenomena are not included in the model.

  9. Model for nonlinear behavior in the self-amplified spontaneous-emission free-electron laser

    NASA Astrophysics Data System (ADS)

    Krinsky, S.

    2004-06-01

    We introduce a simplified model for the saturation of a self-amplified spontaneous-emission free-electron laser. Within this model, we determine the effect of nonlinearity upon the statistical properties of the output radiation. Comparing our results with the computer simulations of Saldin, Schneidmiller, and Yurkov [The Physics of Free Electron Lasers (Springer-Verlag, Berlin, 2000)], we find that the model provides a good description of the average intensity, field correlation function, and coherence time, but underestimates the intensity fluctuation. Asymmetric spectral broadening phenomena are not included in the model.

  10. Soft-x-ray free-electron-laser interaction with materials.

    PubMed

    Hau-Riege, Stefan P; London, Richard A; Chapman, Henry N; Bergh, Magnus

    2007-10-01

    Soft-x-ray free-electron lasers have enabled materials studies in which structural information is obtained faster than the relevant probe-induced damage mechanisms. We present a continuum model to describe the damage process based on hot-dense plasma theory, which includes a description of the energy deposition in the samples, the subsequent dynamics of the sample, and the detector signal. We compared the model predictions with experimental data and mostly found reasonable agreement. In view of future free-electron-laser performance, the model was also used to predict damage dynamics of samples and optical elements at shorter wavelengths and larger photon fluences than currently available.

  11. Soft-x-ray free-electron-laser interaction with materials

    SciTech Connect

    Hau-Riege, Stefan P.; London, Richard A.; Chapman, Henry N.; Bergh, Magnus

    2007-10-15

    Soft-x-ray free-electron lasers have enabled materials studies in which structural information is obtained faster than the relevant probe-induced damage mechanisms. We present a continuum model to describe the damage process based on hot-dense plasma theory, which includes a description of the energy deposition in the samples, the subsequent dynamics of the sample, and the detector signal. We compared the model predictions with experimental data and mostly found reasonable agreement. In view of future free-electron-laser performance, the model was also used to predict damage dynamics of samples and optical elements at shorter wavelengths and larger photon fluences than currently available.

  12. Improve growth rate of Smith-Purcell free-electron laser by Bragg reflector

    SciTech Connect

    Li, D.; Imasaki, K.; Yang, Z.; Tsunawaki, Y.; Asakawa, M. R.; Hangyo, M.; Miyamoto, S.

    2011-05-23

    Grating with Bragg reflectors for the Smith-Purcell free-electron laser is proposed to improve the reflection coefficient, resulting in enhancing the interaction of the surface wave with the electron beam and, consequently, relax the requirements to the electron beam. With the help of particle-in-cell simulations, it has been shown that the usage of Bragg reflectors may improve the growth rate, shorten the time for the device to reach saturation, and lower the start current for the operation of a Smith-Purcell free-electron laser.

  13. The free-electron laser - Maxwell's equations driven by single-particle currents

    NASA Technical Reports Server (NTRS)

    Colson, W. B.; Ride, S. K.

    1980-01-01

    It is shown that if single particle currents are coupled to Maxwell's equations, the resulting set of self-consistent nonlinear equations describes the evolution of the electron beam and the amplitude and phase of the free-electron-laser field. The formulation is based on the slowly varying amplitude and phase approximation, and the distinction between microscopic and macroscopic scales, which distinguishes the microscopic bunching from the macroscopic pulse propagation. The capabilities of this new theoretical approach become apparent when its predictions for the ultrashort pulse free-electron laser are compared to experimental data; the optical pulse evolution, determined simply and accurately, agrees well with observations.

  14. W.M. Keck-Vanderbilt Free-Electron Laser Center facilities

    NASA Astrophysics Data System (ADS)

    Gabella, William E.; Feng, Bibo; Kozub, John A.; Piston, David W.

    2002-04-01

    The W.M. Keck-Vanderbilt Free-electron Laser Center operates a reliable free-electron laser (FEL) that is used in human surgical trials, as well as in basic and applied sciences. The wavelength of the FEL is tunable from 2.1 micrometers to 9.6 micrometers , delivering above 50 mJ per macropulse with a repetition rate of 30 Hz. For soft tissue surgery, especially neurosurgery and surgery on the optic nerve, a wavelength of 6.45 micrometers has been found to ablate with little collateral damage. The free-electron laser beam is delivered to experiments approximately 2000 hours each year. The Center also supports several other tools useful for biomedical experiments: an optical parametric generator laser system with tunable wavelength similar to the free- electron laser except it has much lower average power; a Fourier transform infrared spectrometer to characterize samples; several devices for in vivo imaging including an optical coherence tomography setup, a two-photon fluorescent confocal microscope, and a cooled, integrating camera capable of imaging luciferin-luciferase reactions within the body of a mouse. The Center also houses a tunable, monochromatic x-ray source based on Compton backscattering of a laser off of a relativistic electron beam.

  15. X-RAY FREE-ELECTRON LASERS: PRINCIPLES, PROPERTIES AND APPLICATIONSf*9493

    SciTech Connect

    Stohr, Joachim

    2002-11-25

    Creating matter from the vacuum, taking an atomic scale motion picture of a chemical process in a time of a few femtoseconds (1 fs = 10{sup -15} sec) or unraveling the complex molecular structure of a single protein or virus. These are some of the new exciting experiments envisioned with a novel radiation source, the X-ray free-electron laser (FEL). John Madey and collaborators built the first FEL in the 1970s. It is a powerful and challenging combination of particle accelerator and laser physics and technology. Until recently FELs have been operating at infrared or near ultraviolet wavelengths. A combination of theoretical, experimental, and technological advances has made possible their extension to the X-ray region. X rays have allowed us to see the invisible for almost a century. With their help we have been making great progress in understanding the properties of materials and of living systems. Today the best sources of X rays utilize synchrotron radiation from relativistic electron beams in storage rings. The most advanced, so called third generation facilities, combine storage rings and undulator magnets, and are used by thousands of scientists around the world.

  16. Inverse Free Electron Laser Interactions with Sub-Picosecond High Brightness Electron Beams

    NASA Astrophysics Data System (ADS)

    Moody, Joshua Timothy

    Advanced accelerators have great promise in reducing the size and cost of high energy colliders as well as bringing high brightness x-ray sources to the laboratory tabletop scale. The inverse free electron laser (IFEL) is a high gradient advanced accelerator scheme that is one of the most ecient ways of transferring energy from a laser to an electron beam. By copropagating a laser and a relativistic electron beam through an undulator in vacuum and taking advantage of resonant ponderomotive motion of the electron beam, IFEL avoids the breakdown associated with other schemes that use a material to couple the laser fields to the electron beams. This dissertation provides an overview of IFEL, the photoinjector electron beams to be used in IFEL interactions, and two IFEL applications: compression and synchronization of a photoinjector electron beam to a laser application using THz driven IFEL and high gradient acceleration using IFEL. The numerically investigated THz IFEL application shows that with a 10 microJ THz 8 pulse train, an electron beam bunch length of 100 fs RMS can be compressed to 14 fs RMS and have the beam's time of arrival jitter relative to an external laser reduced by an order of magnitude. High gradient acceleration by IFEL was examined experimentally at Lawrence Livermore National Laboratory (LLNL). This experiment marks the first attempt to use sub-picosecond time pulse, TW peak power scale titanium:sapphire laser pulses to perform IFEL acceleration. The demonstrated energy gain from 77 to 120 MeV combined with particle tracking simulations shows an accelerating gradient of over 200 MeV/m. Because the laser pulse length is the same order as the slippage experienced by the electron beam with respect to the laser and the time of arrival jitter has been measured to be greater than 2 ps, the overlap is investigated through relative single shot time of arrival measurements using electro-optic sampling based spatial encoding techniques. The temporal

  17. Laser Assisted Emittance Exchange: Downsizing the X-ray Free Electron Laser

    SciTech Connect

    Xiang, Dao; /SLAC

    2009-12-11

    A technique is proposed to generate electron beam with ultralow transverse emittance through laser assisted transverse-to-longitudinal emittance exchange. In the scheme a laser operating in the TEM10 mode is used to interact with the electron beam in a dispersive region and to initiate the emittance exchange. It is shown that with the proposed technique one can significantly downsize an x-ray free electron laser (FEL), which may greatly extend the availability of these light sources. A hard x-ray FEL operating at 1.5 {angstrom} with a saturation length within 30 meters using a 3.8 GeV electron beam is shown to be practically feasible.

  18. Terahertz Free-Electron Laser Optical Design and Simulation

    DTIC Science & Technology

    2010-06-01

    Resistivity Float Zone ICBM Inter-Continental Ballistic Missile K Kelvin KE Kinetic Energy Km Kilometer LASER Light Amplification by Stimulated...silicon’s transmission of THz radiation is greatly reduced as temperatures increase above 25 degrees Celsius , as can be seen in Figure 10. This...a single formula expressing the maximum power, P0, sustainable in a lens of thickness , linear expansion coefficient α, absorption coefficient δ

  19. Gain length fitting formula for free-electron lasers with strong space-charge effects

    NASA Astrophysics Data System (ADS)

    Marcus, G.; Hemsing, E.; Rosenzweig, J.

    2011-08-01

    We present a power-fit formula, obtained from a variational analysis using three-dimensional free-electron laser theory, for the gain length of a high-gain free-electron laser’s fundamental mode in the presence of diffraction, uncorrelated energy spread, and longitudinal space-charge effects. The approach is inspired by the work of Xie [Nucl. Instrum. Methods Phys. Res., Sect. A 445, 59 (2000)NIMAER0168-900210.1016/S0168-9002(00)00114-5], and provides a useful shortcut for calculating the gain length of the fundamental Gaussian mode of a free-electron laser having strong space-charge effects in the 3D regime. The results derived from analytic theory are in good agreement with detailed numerical particle simulations that also include higher-order space-charge effects, supporting the assumptions made in the theoretical treatment and the variational solutions obtained in the single-mode limit.

  20. The First Angstrom X-Ray Free-Electron Laser

    SciTech Connect

    Galayda, John; /SLAC

    2012-08-24

    The Linac Coherent Light Source produced its first x-ray laser beam on 10 April 2009. Today it is routinely producing x-ray pulses with energy >2 mJ across the operating range from 820-8,200 eV. The facility has begun operating for atomic/molecular/optical science experiments. Performance of the facility in its first user run (1 October - 21 December) and current machine development activities will be presented. Early results from the preparations for the start of the second user run is also reported.

  1. Millimeter wave tokamak heating and current drive with a high power free electron laser

    SciTech Connect

    Thomassen, K.I.

    1987-01-01

    Experiments on microwave generation using a free electron laser (FEL) have shown this to be an efficient way to generate millimeter wave power in short, intense pulses. Short pulse FEL's have several advantages that make them attractive for application to ECR heating of tokamak fusion reactors. This paper reports on plans made to demonstrate the technology at the Microwave Tokamak Experiment (MTX) Facility.

  2. Nonlinear effects in propagation of radiation of X-ray free-electron lasers

    NASA Astrophysics Data System (ADS)

    Nosik, V. L.

    2016-05-01

    Nonlinear effects accompanying the propagation of high-intensity beams of X-ray free-electron lasers are considered. It is shown that the X-ray wave field in the crystal significantly changes due to the formation of "hollow" atomic shells as a result of the photoelectric effect.

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

    DOEpatents

    Douglas, David R.; Benson, Stephen; Nguyen, Dinh Cong; Tennant, Christopher; Wilson, Guy

    2015-05-26

    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.sub.56>0), and 3) compensating for aberration by using nonlinear magnets in the compressor beam line.

  4. Applications of the Infrared Free Electron Laser in Nonlinear and Time-Resolved Spectroscopy

    NASA Astrophysics Data System (ADS)

    Fann, Wunshain

    1990-01-01

    Free Electron Lasers (FEL) have been envisioned as novel radiation sources tunable over a wide spectral range. In this dissertation I report two types of experiments that used the infrared FEL, Mark III, to study nonlinear optical properties of conjugated polymers and the possibility of long lived vibrational excitations in acetanilide, a hydrogen-bonded molecular crystal.

  5. Effects of Energy Chirp on Echo-Enabled Harmonic Generation Free-Electron Lasers

    SciTech Connect

    Huang, Z.; Ratner, D.; Stupakov, G.; Xiang, D.; /SLAC

    2009-02-23

    We study effects of energy chirp on echo-enabled harmonic generation (EEHG). Analytical expressions are compared with numerical simulations for both harmonic and bunching factors. We also discuss the EEHG free-electron laser bandwidth increase due to an energy-modulated beam and its pulse length dependence on the electron energy chirp.

  6. Time-Dependent, Three-Dimensional Simulation of Free-Electron-Laser Oscillators

    SciTech Connect

    Slot, P. J. M. van der; Boller, K.-J.; Freund, H. P.; Miner, W. H. Jr.; Benson, S. V.; Shinn, M.

    2009-06-19

    We describe a procedure for the simulation of free-electron-laser (FEL) oscillators. The simulation uses a combination of the MEDUSA simulation code for the FEL interaction and the OPC code to model the resonator. The simulations are compared with recent observations of the oscillator at the Thomas Jefferson National Accelerator Facility and are in substantial agreement with the experiment.

  7. Photoelectron dynamics in x-ray free-electron-laser diffractive imaging of biological samples.

    PubMed

    Hau-Riege, Stefan P

    2012-06-08

    X-ray free electron lasers hold the promise of enabling atomic-resolution diffractive imaging of single biological molecules. We develop a hybrid continuum-particle model to describe the x-ray induced damage and find that the photoelectron dynamics and electrostatic confinement strongly affect the time scale of the damage processes. These phenomena are not fully captured in hydrodynamic modeling approaches.

  8. The “SF” System of Sextupoles for the JLAB 10 KW Free Electron Laser Upgrade

    SciTech Connect

    George Biallas, Mark Augustine, Kenneth Baggett, David Douglas, Robin Wines

    2009-05-01

    The characteristics of the system of “SF” Sextupoles for the infrared Free Electron Laser Upgrade1 at the Thomas Jefferson National Accelerator Facility (JLab) are described. These eleven sextupoles possess a large field integral (2.15 T/m) with +/- 0.2%

  9. Collective Effects on the Operation of Free Electron Lasers with an Axial Guide Field.

    DTIC Science & Technology

    1982-02-19

    lnstituto de Fisica , Universidade Federal do Rio Grande do Sul, 90.000 Porto Alegre-RS, Brazil 19. KEY WORDS (Continue on rover.ee d if necessry aid...Identify by block numer) Raman scattering Free electron lasers Coherent radiation Millimeter waves 20. ABSTRACT (Continue on overee olde It neco.. ary end

  10. Beam dynamics and rf evolution in a multistage klystron-like free- electron laser

    SciTech Connect

    Ohnuma, S. . Inst. for Beam Particle Dynamics); Takayama, K. . Inst. for Beam Particle Dynamics Texas Accelerator Center, The Woodlands, TX )

    1991-01-01

    Current understandings of beam dynamics and RF evolution in a klystron-like free-electron laser are present. Phase sensitiveness to injection jitters estimated by existing two theories is discussed. BBU suppression due to linear detuning is proposed as an alternative of ever proposed techniques. 13 refs., 2 figs., 1 tab.

  11. Current status of the superconducting RF linac driver for the JAERI Free Electron Laser Facility

    SciTech Connect

    Minehara, E.J.; Sugimoto, M.; Sawamura, M.

    1995-12-31

    The commissioning of the superconducting rf linac driver for the JAERI free electron laser facility has been successfully performed at 10{approx}20 MeV before the end of the 1994 Japanese fiscal year. The performance obtained during the commissioning and current status of the JAERI FEL program at Tokai will be reported in detail.

  12. High-harmonic inverse-free-electron-laser interaction at 800 nm.

    PubMed

    Sears, Christopher M S; Colby, Eric R; Cowan, Benjamin M; Siemann, Robert H; Spencer, James E; Byer, Robert L; Plettner, Tomas

    2005-11-04

    We present the first direct observation of a higher-order inverse-free-electron-laser (IFEL) interaction. Interaction at the fourth, fifth, and sixth harmonics is observed from an IFEL operating at 800 nm. The harmonic spacing, relative harmonic strength, and transverse beam overlap of the interaction are all in good agreement with tracking simulations.

  13. High-Harmonic Inverse-Free-Electron-Laser Interaction at 800 nm

    NASA Astrophysics Data System (ADS)

    Sears, Christopher M. S.; Colby, Eric R.; Cowan, Benjamin M.; Siemann, Robert H.; Spencer, James E.; Byer, Robert L.; Plettner, Tomas

    2005-11-01

    We present the first direct observation of a higher-order inverse-free-electron-laser (IFEL) interaction. Interaction at the fourth, fifth, and sixth harmonics is observed from an IFEL operating at 800 nm. The harmonic spacing, relative harmonic strength, and transverse beam overlap of the interaction are all in good agreement with tracking simulations.

  14. Chirped-Pulse Inverse Free-Electron Laser: A High Gradient Vacuum Accelerator

    NASA Astrophysics Data System (ADS)

    Hartemann, F.; Landahl, E.; Song, L.; Luhmann, N. C., Jr.; Baldis, H. A.

    1998-11-01

    The inverse free-electron laser (IFEL) interaction has been demonstrated as a viable vacuum laser acceleration process. It is shown here that by using an ultrahigh intensity chirped laser pulse, the dephasing length can be increased considerably, thus yielding high gradient IFEL acceleration. In addition, diffraction can be alleviated by taking advantage of the laser optical bandwidth with all-reflective, negative dispersion focusing optics to produce a line focus. The combination of these two novel ideas results in a compact, efficient vacuum laser accelerator.

  15. Compact beam transport system for free-electron lasers driven by a laser plasma accelerator

    NASA Astrophysics Data System (ADS)

    Liu, Tao; Zhang, Tong; Wang, Dong; Huang, Zhirong

    2017-02-01

    Utilizing laser-driven plasma accelerators (LPAs) as a high-quality electron beam source is a promising approach to significantly downsize the x-ray free-electron laser (XFEL) facility. A multi-GeV LPA beam can be generated in several-centimeter acceleration distance, with a high peak current and a low transverse emittance, which will considerably benefit a compact FEL design. However, the large initial angular divergence and energy spread make it challenging to transport the beam and realize FEL radiation. In this paper, a novel design of beam transport system is proposed to maintain the superior features of the LPA beam and a transverse gradient undulator (TGU) is also adopted as an effective energy spread compensator to generate high-brilliance FEL radiation. Theoretical analysis and numerical simulations are presented based on a demonstration experiment with an electron energy of 380 MeV and a radiation wavelength of 30 nm.

  16. The Chirped-Pulse Inverse Free-Electron Laser: a High-Gradient Vacuum Laser Accelerator

    NASA Astrophysics Data System (ADS)

    Hartemann, Fred; Baldis, Hector; Gibson, David; Kerman, Arthur; Landahl Luhmann, Eric, Jr.; Troha, Anthony

    2000-10-01

    The inverse free-electron laser (IFEL) interaction is studied theoretically and computationally in the case where the drive laser intensity approaches the relativistic regime, and the pulse duration is only a few optical cycles long. The IFEL concept has been demonstrated as a viable vacuum laser acceleration process; it is shown here that by using an ultrashort, ultrahigh-intensity drive laser pulse, the IFEL interaction bandwidth and accelerating gradient are increased considerably, thus yielding large energy gains. Using a chirped pulse and negative dispersion focusing optics allows one to take further advantage of the laser optical bandwidth and produce a chromatic line focus maximizing the gradient. The combination of these novel ideas results in a compact vacuum laser accelerator capable of accelerating picosecond electron bunches with a high gradient (GeV/m) and very low energy spread. This work was performed under the auspices of DoE by LLNL under Contract No. W-7405-ENG-48, and was partially supported by NIH Contract No. N01-CO-97113 and AFOSR MURI Grant No. F49620-99-1-0297.

  17. Free-Electron Lasers, Thermal Diffusion, Chemical Kinetics, and Surgery

    NASA Astrophysics Data System (ADS)

    Edwards, Glenn; Hutson, M. Shane

    2001-11-01

    Experiments demonstrate that the Mark-III FEL is a particularly effective tool for etching soft matter with remarkably little damage surrounding the site when tuned to wavelengths near 6.45 microns. Based on these observatons, human neuorsurgical and ophthalmic procedures were developed and have been performed successfully. A thermodynamic model was proposed to account for the wavelength dependence; however, the dynamics have not been well understood. We have theoretically investigated thermal diffusion and chemical kinetics in a system of alternating layers of protein and water as heated by a Mark-III FEL. The model is representative of cornea and the exposure conditions are comparable to previous experimental FEL investigations. A substantial temperature enhancement develops in the surface layer on the ten-nanosecond time scale. We consider the onset of both the helix-coil transition and chemical bond breaking of collagen in terms of the thermal, chemical, and structural properties of the system as well as laser wavelength and pulse structure.

  18. Reversible Electron Beam Heating for Suppression of Microbunching Instabilities at Free-Electron Lasers

    SciTech Connect

    Behrens, Christopher; Huang, Zhirong; Xiang, Dao; /SLAC

    2012-05-30

    The presence of microbunching instabilities due to the compression of high-brightness electron beams at existing and future x-ray free-electron lasers (FELs) results in restrictions on the attainable lasing performance and renders beam imaging with optical transition radiation impossible. The instability can be suppressed by introducing additional energy spread, i.e., heating the electron beam, as demonstrated by the successful operation of the laser heater system at the Linac Coherent Light Source. The increased energy spread is typically tolerable for self-amplified spontaneous emission FELs but limits the effectiveness of advanced FEL schemes such as seeding. In this paper, we present a reversible electron beam heating system based on two transverse deflecting radio-frequency structures (TDSs) upstream and downstream of a magnetic bunch compressor chicane. The additional energy spread is introduced in the first TDS, which suppresses the microbunching instability, and then is eliminated in the second TDS. We show the feasibility of the microbunching gain suppression based on calculations and simulations including the effects of coherent synchrotron radiation. Acceptable electron beam and radio-frequency jitter are identified, and inherent options for diagnostics and on-line monitoring of the electron beam's longitudinal phase space are discussed.

  19. Attosecond interferometry with self-amplified spontaneous emission of a free-electron laser

    NASA Astrophysics Data System (ADS)

    Usenko, Sergey; Przystawik, Andreas; Jakob, Markus Alexander; Lazzarino, Leslie Lamberto; Brenner, Günter; Toleikis, Sven; Haunhorst, Christian; Kip, Detlef; Laarmann, Tim

    2017-05-01

    Light-phase-sensitive techniques, such as coherent multidimensional spectroscopy, are well-established in a broad spectral range, already spanning from radio-frequencies in nuclear magnetic resonance spectroscopy to visible and ultraviolet wavelengths in nonlinear optics with table-top lasers. In these cases, the ability to tailor the phases of electromagnetic waves with high precision is essential. Here we achieve phase control of extreme-ultraviolet pulses from a free-electron laser (FEL) on the attosecond timescale in a Michelson-type all-reflective interferometric autocorrelator. By varying the relative phase of the generated pulse replicas with sub-cycle precision we observe the field interference, that is, the light-wave oscillation with a period of 129 as. The successful transfer of a powerful optical method towards short-wavelength FEL science and technology paves the way towards utilization of advanced nonlinear methodologies even at partially coherent soft X-ray FEL sources that rely on self-amplified spontaneous emission.

  20. Attosecond interferometry with self-amplified spontaneous emission of a free-electron laser

    PubMed Central

    Usenko, Sergey; Przystawik, Andreas; Jakob, Markus Alexander; Lazzarino, Leslie Lamberto; Brenner, Günter; Toleikis, Sven; Haunhorst, Christian; Kip, Detlef; Laarmann, Tim

    2017-01-01

    Light-phase-sensitive techniques, such as coherent multidimensional spectroscopy, are well-established in a broad spectral range, already spanning from radio-frequencies in nuclear magnetic resonance spectroscopy to visible and ultraviolet wavelengths in nonlinear optics with table-top lasers. In these cases, the ability to tailor the phases of electromagnetic waves with high precision is essential. Here we achieve phase control of extreme-ultraviolet pulses from a free-electron laser (FEL) on the attosecond timescale in a Michelson-type all-reflective interferometric autocorrelator. By varying the relative phase of the generated pulse replicas with sub-cycle precision we observe the field interference, that is, the light-wave oscillation with a period of 129 as. The successful transfer of a powerful optical method towards short-wavelength FEL science and technology paves the way towards utilization of advanced nonlinear methodologies even at partially coherent soft X-ray FEL sources that rely on self-amplified spontaneous emission. PMID:28555640

  1. Considerations for a free-electron laser-based extreme-ultraviolet lithography program

    NASA Astrophysics Data System (ADS)

    Hosler, Erik R.; Wood, Obert R.; Barletta, William A.; Mangat, Pawitter J. S.; Preil, Moshe E.

    2015-03-01

    Recent years have seen great strides in the development of extreme ultraviolet (EUV) laser-produced plasma sources. Field deployed EUV exposure tools are now capable of facilitating advanced technology node development. Nevertheless, as the required manufacturing exposure dose scales, EUV sources must follow suit and provide 500- 1000 W to maintain production throughputs. A free-electron laser (FEL) offers a cost effective, single-source alternative for powering an entire EUV lithography program. FEL integration into semiconductor fab architecture will require both unique facility considerations as well as a paradigm shift in lithography operations. Critical accelerator configurations relating to energy recovery, multi-turn acceleration, and operational mode are discussed from engineering/scientific, cost-minimization, and safety perspectives. Furthermore, the individual components of a FEL (electron injector, RF systems, undulator, etc.) are examined with respect to both design and cost, considering existing technology as well as prospective innovations. Finally, FEL development and deployment roadmaps are presented, focusing on manufacturer deployment for the 5 nm or 3 nm technology nodes.[1-3

  2. Low-frequency wiggler modes in the free-electron laser with a dusty magnetoplasma medium

    NASA Astrophysics Data System (ADS)

    Jafari, S.

    2015-07-01

    An advanced incremental scheme for generating tunable coherent radiation in a free-electron laser has been presented: the basic concept is the use of a relativistic electron beam propagating through a magnetized dusty plasma channel where dust helicon, dust Alfven and coupled dust cyclotron-Alfven waves can play a role as a low-frequency wiggler, triggering coherent emissions. The wiggler wavelength at the sub-mm level allows one to reach the wavelength range from a few nm down to a few Å with moderately relativistic electrons of kinetic energies of a few tens/hundreds of MeV. The laser gain and the effects of beam self-electric and self-magnetic fields on the gain have been estimated and compared with findings of the helical magnetic and electromagnetic wigglers in vacuum. To study the chaotic regions of the electron motion in the dusty plasma wave wiggler, a time independent Hamiltonian has been obtained. The Poincare surface of a section map has been used numerically to analyze the nonintegrable system where chaotic regions in phase-space emerge. This concept opens a path toward a new generation of synchrotron sources based on compact plasma structures.

  3. Operation of the Free-Electron Laser at DESY and First Scientific Experiments

    NASA Astrophysics Data System (ADS)

    Feldhaus, Josef

    2007-01-01

    The free-electron laser at DESY in Hamburg (FLASH) is the first free-electron laser built for the vacuum-ultraviolet (VUV) and soft X-ray region. It started user operation in summer 2005 and has been operated routinely for scientific experiments at 32 nm wavelength providing up to 150 pulses per second with GW peak power and a pulse duration between 20 and 50 fs. Recently also shorter wavelengths at 25.5 nm and ˜13 nm have been used for experiments. The FEL beam can be switched between four experimental stations by movable mirrors. A synchronised optical laser system is available for pump-probe experiments. Diagnostics has been implemented to monitor the pulse energy and its timing with respect to the optical laser. The current status of the facility is reviewed and examples of first user experiments are presented.

  4. Mode-selective phonon excitation in gallium nitride using mid-infrared free-electron laser

    NASA Astrophysics Data System (ADS)

    Kagaya, Muneyuki; Yoshida, Kyohei; Zen, Heishun; Hachiya, Kan; Sagawa, Takashi; Ohgaki, Hideaki

    2017-02-01

    The single-phonon mode was selectively excited in a solid-state sample. A mid-infrared free-electron laser, which was tuned to the target phonon mode, was irradiated onto a crystal cooled to a cryogenic temperature, where modes other than the intended excitation were suppressed. An A 1(LO) vibrational mode excitation on GaN(0001) face was demonstrated. Anti-Stokes Raman scattering was used to observe the excited vibrational mode, and the appearance and disappearance of the scattering band at the target wavenumber were confirmed to correspond to on and off switching of the pump free-electron laser and were fixed to the sample vibrational mode. The sum-frequency generation signals of the pump and probe lasers overlapped the Raman signals and followed the wavenumber shift of the pump laser.

  5. Atomic inner-shell laser at 1.5-ångström wavelength pumped by an X-ray free-electron laser.

    PubMed

    Yoneda, Hitoki; Inubushi, Yuichi; Nagamine, Kazunori; Michine, Yurina; Ohashi, Haruhiko; Yumoto, Hirokatsu; Yamauchi, Kazuto; Mimura, Hidekazu; Kitamura, Hikaru; Katayama, Tetsuo; Ishikawa, Tetsuya; Yabashi, Makina

    2015-08-27

    Since the invention of the first lasers in the visible-light region, research has aimed to produce short-wavelength lasers that generate coherent X-rays; the shorter the wavelength, the better the imaging resolution of the laser and the shorter the pulse duration, leading to better temporal resolution in probe measurements. Recently, free-electron lasers based on self-amplified spontaneous emission have made it possible to generate a hard-X-ray laser (that is, the photon energy is of the order of ten kiloelectronvolts) in an ångström-wavelength regime, enabling advances in fields from ultrafast X-ray spectrosopy to X-ray quantum optics. An atomic laser based on neon atoms and pumped by a soft-X-ray (that is, a photon energy of less than one kiloelectronvolt) free-electron laser has been achieved at a wavelength of 14 nanometres. Here, we use a copper target and report a hard-X-ray inner-shell atomic laser operating at a wavelength of 1.5 ångströms. X-ray free-electron laser pulses with an intensity of about 10(19) watts per square centimetre tuned to the copper K-absorption edge produced sufficient population inversion to generate strong amplified spontaneous emission on the copper Kα lines. Furthermore, we operated the X-ray free-electron laser source in a two-colour mode, with one colour tuned for pumping and the other for the seed (starting) light for the laser.

  6. Atomic inner-shell laser at 1.5-ångström wavelength pumped by an X-ray free-electron laser

    NASA Astrophysics Data System (ADS)

    Yoneda, Hitoki; Inubushi, Yuichi; Nagamine, Kazunori; Michine, Yurina; Ohashi, Haruhiko; Yumoto, Hirokatsu; Yamauchi, Kazuto; Mimura, Hidekazu; Kitamura, Hikaru; Katayama, Tetsuo; Ishikawa, Tetsuya; Yabashi, Makina

    2015-08-01

    Since the invention of the first lasers in the visible-light region, research has aimed to produce short-wavelength lasers that generate coherent X-rays; the shorter the wavelength, the better the imaging resolution of the laser and the shorter the pulse duration, leading to better temporal resolution in probe measurements. Recently, free-electron lasers based on self-amplified spontaneous emission have made it possible to generate a hard-X-ray laser (that is, the photon energy is of the order of ten kiloelectronvolts) in an ångström-wavelength regime, enabling advances in fields from ultrafast X-ray spectrosopy to X-ray quantum optics. An atomic laser based on neon atoms and pumped by a soft-X-ray (that is, a photon energy of less than one kiloelectronvolt) free-electron laser has been achieved at a wavelength of 14 nanometres. Here, we use a copper target and report a hard-X-ray inner-shell atomic laser operating at a wavelength of 1.5 ångströms. X-ray free-electron laser pulses with an intensity of about 1019 watts per square centimetre tuned to the copper K-absorption edge produced sufficient population inversion to generate strong amplified spontaneous emission on the copper Kα lines. Furthermore, we operated the X-ray free-electron laser source in a two-colour mode, with one colour tuned for pumping and the other for the seed (starting) light for the laser.

  7. Nonlinear harmonic generation in high-gain free-electron lasers

    SciTech Connect

    Dattoli, G.; Ottaviani, P.L.; Pagnutti, S.

    2005-06-01

    We reconsider the derivation of semianalytical expressions providing the most significant aspects of the high-gain free-electron laser dynamics. We obtain new expressions for the growth of the laser power, of the e-beam-induced energy spread, and of the higher-order nonlinearly generated harmonics. The procedure we employ, based on theoretical ansatz and fitting methods, allows the determination of crucial quantities like the expected harmonic output power and its dependences on the e-beam parameters.

  8. Design of a Compact, Optically Guided, Pinched, Megawatt Class Free-Electron Laser

    DTIC Science & Technology

    2007-06-08

    period May 2004 to May 2006 Prepared by Phillip Sprangle (Principal Investigator) Joseph Pefiano Bahman Hafizi* * Icarus Research, Inc., P.O. Box 30780...L.M. Young and H.P. Freund, J. Directed Energy 1, 171 ( 2004 ). [6] W.B. Colson, A. Todd and G.R. Neil, "A high power free electron laser using a short...Laser PHILUP SPRANGLE JOSEPH PENANO Beam Physics Branch Plasma Physics Division BAHMAN HAFIZI Icarus Research, Inc. Bethesda, Maryland June 8, 2007

  9. Optical modeling of induction-linac driven free-electron lasers

    SciTech Connect

    Scharlemann, E.T.; Fawley, W.M.

    1986-03-31

    The free-electron laser (FEL) simulation code FRED, developed at Lawrence Livermore National Laboratory (LLNL) primarily to model single-pass FEL amplifiers driven by induction linear accelerators, is described. The main emphasis is on the modeling of optical propagation in the laser and on the differences between the requirements for modeling rf-linac-driven vs. induction-linac-driven FELs. Examples of optical guiding and mode cleanup are presented for a 50 ..mu..m FEL.

  10. Optical properties of the output of a high-gain, self-amplified free-electron laser.

    SciTech Connect

    Li, Y.; Lewellen, J.; Huang, Z.; Krinsky, S.; Accelerator Systems Division; BNL

    2004-01-01

    The temporal structure and phase evolutions of a high-gain, self-amplified free-electron laser are measured, including single-shot analysis and statistics over many shots. Excellent agreement with the theory of free-electron laser and photon statistics is found.

  11. Large-Scale Production of Carbon Nanotubes Using the Jefferson Lab Free Electron Laser

    NASA Technical Reports Server (NTRS)

    Holloway, Brian C.

    2003-01-01

    We report on our interdisciplinary program to use the Free Electron Laser (FEL) at the Thomas Jefferson National Accelerator Facility (J-Lab) for high-volume pulsed laser vaporization synthesis of carbon nanotubes. Based in part on the funding of from this project, a novel nanotube production system was designed, tested, and patented. Using this new system nanotube production rates over 100 times faster than conventional laser systems were achieved. Analysis of the material produced shows that it is of as high a quality as the standard laser-based materials.

  12. Bremsstrahlung and Line Spectroscopy of Warm Dense Aluminum Plasma Generated by EUV Free Electron Laser

    SciTech Connect

    Zastrau, U; Fortmann, C; Faustlin, R; Bornath, T; Cao, L F; Doppner, T; Dusterer, S; Forster, E; Glenzer, S H; Gregori, G; Holl, A; Laarmann, T; Lee, H; Meiwes-Broer, K; Przystawik, A; Radcliffe, P; Redmer, R; Reinholz, H; Ropke, G; Tiggesbaumker, J; Thiele, R; Truong, N X; Uschmann, I; Toleikis, S; Tschentscher, T; Wierling, A

    2008-03-07

    We report on the novel creation of a solid density aluminum plasma using free electron laser radiation at 13.5 nm wavelength. Ultrashort pulses of 30 fs duration and 47 {micro}J pulse energy were focused on a spot of 25 {micro}m diameter, yielding an intensity of 3 x 10{sup 14} W/cm{sup 2} on the bulk Al-target. The radiation emitted from the plasma was measured using a high resolution, high throughput EUV spectrometer. The analysis of both bremsstrahlung and line spectra results in an estimated electron temperature of (30 {+-} 10) eV, which is in very good agreement with radiation hydrodynamics simulations of the laser-target-interaction. This demonstrates the feasibility of exciting plasmas at warm dense matter conditions using EUV free electron lasers and their accurate characterization by EUV spectroscopy.

  13. Chirped pulse amplification in an extreme-ultraviolet free-electron laser

    PubMed Central

    Gauthier, David; Allaria, Enrico; Coreno, Marcello; Cudin, Ivan; Dacasa, Hugo; Danailov, Miltcho Boyanov; Demidovich, Alexander; Di Mitri, Simone; Diviacco, Bruno; Ferrari, Eugenio; Finetti, Paola; Frassetto, Fabio; Garzella, David; Künzel, Swen; Leroux, Vincent; Mahieu, Benoît; Mahne, Nicola; Meyer, Michael; Mazza, Tommaso; Miotti, Paolo; Penco, Giuseppe; Raimondi, Lorenzo; Ribič, Primož Rebernik; Richter, Robert; Roussel, Eléonore; Schulz, Sebastian; Sturari, Luca; Svetina, Cristian; Trovò, Mauro; Walker, Paul Andreas; Zangrando, Marco; Callegari, Carlo; Fajardo, Marta; Poletto, Luca; Zeitoun, Philippe; Giannessi, Luca; De Ninno, Giovanni

    2016-01-01

    Chirped pulse amplification in optical lasers is a revolutionary technique, which allows the generation of extremely powerful femtosecond pulses in the infrared and visible spectral ranges. Such pulses are nowadays an indispensable tool for a myriad of applications, both in fundamental and applied research. In recent years, a strong need emerged for light sources producing ultra-short and intense laser-like X-ray pulses, to be used for experiments in a variety of disciplines, ranging from physics and chemistry to biology and material sciences. This demand was satisfied by the advent of short-wavelength free-electron lasers. However, for any given free-electron laser setup, a limit presently exists in the generation of ultra-short pulses carrying substantial energy. Here we present the experimental implementation of chirped pulse amplification on a seeded free-electron laser in the extreme-ultraviolet, paving the way to the generation of fully coherent sub-femtosecond gigawatt pulses in the water window (2.3–4.4 nm). PMID:27905401

  14. Chirped pulse amplification in an extreme-ultraviolet free-electron laser

    NASA Astrophysics Data System (ADS)

    Gauthier, David; Allaria, Enrico; Coreno, Marcello; Cudin, Ivan; Dacasa, Hugo; Danailov, Miltcho Boyanov; Demidovich, Alexander; di Mitri, Simone; Diviacco, Bruno; Ferrari, Eugenio; Finetti, Paola; Frassetto, Fabio; Garzella, David; Künzel, Swen; Leroux, Vincent; Mahieu, Benoît; Mahne, Nicola; Meyer, Michael; Mazza, Tommaso; Miotti, Paolo; Penco, Giuseppe; Raimondi, Lorenzo; Ribič, Primož Rebernik; Richter, Robert; Roussel, Eléonore; Schulz, Sebastian; Sturari, Luca; Svetina, Cristian; Trovò, Mauro; Walker, Paul Andreas; Zangrando, Marco; Callegari, Carlo; Fajardo, Marta; Poletto, Luca; Zeitoun, Philippe; Giannessi, Luca; de Ninno, Giovanni

    2016-12-01

    Chirped pulse amplification in optical lasers is a revolutionary technique, which allows the generation of extremely powerful femtosecond pulses in the infrared and visible spectral ranges. Such pulses are nowadays an indispensable tool for a myriad of applications, both in fundamental and applied research. In recent years, a strong need emerged for light sources producing ultra-short and intense laser-like X-ray pulses, to be used for experiments in a variety of disciplines, ranging from physics and chemistry to biology and material sciences. This demand was satisfied by the advent of short-wavelength free-electron lasers. However, for any given free-electron laser setup, a limit presently exists in the generation of ultra-short pulses carrying substantial energy. Here we present the experimental implementation of chirped pulse amplification on a seeded free-electron laser in the extreme-ultraviolet, paving the way to the generation of fully coherent sub-femtosecond gigawatt pulses in the water window (2.3-4.4 nm).

  15. Chirped pulse amplification in an extreme-ultraviolet free-electron laser.

    PubMed

    Gauthier, David; Allaria, Enrico; Coreno, Marcello; Cudin, Ivan; Dacasa, Hugo; Danailov, Miltcho Boyanov; Demidovich, Alexander; Di Mitri, Simone; Diviacco, Bruno; Ferrari, Eugenio; Finetti, Paola; Frassetto, Fabio; Garzella, David; Künzel, Swen; Leroux, Vincent; Mahieu, Benoît; Mahne, Nicola; Meyer, Michael; Mazza, Tommaso; Miotti, Paolo; Penco, Giuseppe; Raimondi, Lorenzo; Ribič, Primož Rebernik; Richter, Robert; Roussel, Eléonore; Schulz, Sebastian; Sturari, Luca; Svetina, Cristian; Trovò, Mauro; Walker, Paul Andreas; Zangrando, Marco; Callegari, Carlo; Fajardo, Marta; Poletto, Luca; Zeitoun, Philippe; Giannessi, Luca; De Ninno, Giovanni

    2016-12-01

    Chirped pulse amplification in optical lasers is a revolutionary technique, which allows the generation of extremely powerful femtosecond pulses in the infrared and visible spectral ranges. Such pulses are nowadays an indispensable tool for a myriad of applications, both in fundamental and applied research. In recent years, a strong need emerged for light sources producing ultra-short and intense laser-like X-ray pulses, to be used for experiments in a variety of disciplines, ranging from physics and chemistry to biology and material sciences. This demand was satisfied by the advent of short-wavelength free-electron lasers. However, for any given free-electron laser setup, a limit presently exists in the generation of ultra-short pulses carrying substantial energy. Here we present the experimental implementation of chirped pulse amplification on a seeded free-electron laser in the extreme-ultraviolet, paving the way to the generation of fully coherent sub-femtosecond gigawatt pulses in the water window (2.3-4.4 nm).

  16. Nonlinear Laser Acceleration in a Magnetostatic Field and the Chirped-Pulse Inverse Free Electron Laser

    NASA Astrophysics Data System (ADS)

    Kerman, A. K.; Hartemann, F. V.; Gibson, D. J.; Troha, A. L.

    2001-10-01

    A novel, high-gradient acceleration process is introduced, whereby electrons are interacting in vacuum with a femtosecond laser operation at relativistic intensities, and a static magnetic field. The interaction is best described as a three-stage process: first, the electron energy is boosted by the radiation pressure; at the peak energy, a transverse, static magnetic field is applied, which optimally dephases the electron and the wave; finally, the dephased electron is further accelerated in the second half of the pulse. The final energy is γ_+∞/γ_-∞ ≈ (1+A_0^2)^2, where γ_-∞ is the initial energy and A0 is the normalized laser potential. The inverse free-electron laser(IFEL) interaction is studied both theoretically and numerically in the case where the drive laser intensity approaches the relativistic regime, and the pulse duration is only a few optical cycles long. A computer code which takes into account the three-dimensional nature of the interaction is in development and results will be presented as available.

  17. Demonstration of inverse free-electron laser seeding in a sub-80 K, short period cryogenic undulator

    NASA Astrophysics Data System (ADS)

    OʼShea, F. H.; Knyazik, Andrey; Marinelli, A.; Rosenzweig, J. B.; Dunning, M.; Hast, C.; Hemsing, E.; Jobe, K.; Nelson, J.; Weathersby, S.; Xiang, D.; Holy, F.; Grüner, F.; Bahrdt, J.

    2014-12-01

    Short period, high field undulators have been shown to permit operation of x-ray free-electron lasers with short gain-lengths, and at unprecedented short wavelengths. In addition, the reduced beam energy required to reach resonance with a given radiation wavelength in short period undulators could prove useful in advanced inverse free-electron laser (IFEL) seeding schemes for future light sources, such as high-gain harmonic generation and echo-enabled harmonic generation, or in IFEL acceleration. We report here the in situ beam testing of a 9 mm period length cryogenic undulator having undulator parameter near unity in the context appropriate for advanced seeding and acceleration schemes, a linear accelerator. Because of the short period length of the undulator, a 47 MeV high-brightness electron beam could be used to produce near infrared photons via the undulator radiation mechanism. The undulator radiation was observed through a filter and the spectral response of the undulator is compared to simulation. Finally, an 800 nm seed laser was introduced in order to generate an energy modulation via the IFEL mechanism. Resonance between the electron beam and the laser seed was achieved without detailed knowledge of the temperature dependent undulator magnetic field through the observation of the undulator radiation. The energy modulation (and concomitant energy spread increase) of the electron beam was observed both directly in an electron beam spectrometer and indirectly via coherent transition radiation after conversion to a density modulation in a longitudinally dispersive chicane.

  18. Time-resolved photoelectron imaging using a femtosecond UV laser and a VUV free-electron laser

    SciTech Connect

    Liu, S. Y.; Nishizawa, K.; Ogi, Y.; Fuji, T.; Mizuno, T.; Horio, T.; Kohguchi, H.; Nagasono, M.; Tono, K.; Yabashi, M.; Ishikawa, T.; Togashi, T.; Ohashi, H.; Kimura, H.; Senba, Y.; Suzuki, T.

    2010-03-15

    A time-resolved photoelectron imaging using a femtosecond ultraviolet (UV) laser and a vacuum UV free-electron laser is presented. Ultrafast internal conversion and intersystem crossing in pyrazine in a supersonic molecular beam were clearly observed in the time profiles of photoioinzation intensity and time-dependent photoelectron images.

  19. Inverse Cerenkov laser accelerator and observation of femtosecond electron beam microbunching by inverse free electron laser accelerator

    NASA Astrophysics Data System (ADS)

    Liu, Yabo

    This dissertation presents results from an experiment demonstrating the feasibility of using laser electric field accelerating relativistic electrons at the Accelerator Test Facility of Brookhaven National Laboratory. The gas breakdown associated with the laser acceleration process is discussed. In the second half of this dissertation we demonstrate the microbunching of using Inverse Free Electron Laser (IFEL) Accelerator. It has proven experimentally that the IFEL accelerator is capable of functioning as a prebuncher for Inverse Cerenkov Laser Accelerator use.

  20. Two-colour hard X-ray free-electron laser with wide tunability.

    PubMed

    Hara, Toru; Inubushi, Yuichi; Katayama, Tetsuo; Sato, Takahiro; Tanaka, Hitoshi; Tanaka, Takashi; Togashi, Tadashi; Togawa, Kazuaki; Tono, Kensuke; Yabashi, Makina; Ishikawa, Tetsuya

    2013-01-01

    Ultrabrilliant, femtosecond X-ray pulses from X-ray free-electron lasers (XFELs) have promoted the investigation of exotic interactions between intense X-rays and matters, and the observation of minute targets with high spatio-temporal resolution. Although a single X-ray beam has been utilized for these experiments, the use of multiple beams with flexible and optimum beam parameters should drastically enhance the capability and potentiality of XFELs. Here we show a new light source of a two-colour double-pulse (TCDP) XFEL in hard X-rays using variable-gap undulators, which realizes a large and flexible wavelength separation of more than 30% with an ultraprecisely controlled time interval in the attosecond regime. Together with sub-10-fs pulse duration and multi-gigawatt peak powers, the TCDP scheme enables us to elucidate X-ray-induced ultrafast transitions of electronic states and structures, which will significantly contribute to the advancement of ultrafast chemistry, plasma and astronomical physics, and quantum X-ray optics.

  1. Extreme ultraviolet resonant inelastic X-ray scattering (RIXS) at a seeded free-electron laser

    PubMed Central

    Dell’Angela, M.; Hieke, F.; Malvestuto, M.; Sturari, L.; Bajt, S.; Kozhevnikov, I. V.; Ratanapreechachai, J.; Caretta, A.; Casarin, B.; Glerean, F.; Kalashnikova, A. M.; Pisarev, R. V.; Chuang, Y.-D.; Manzoni, G.; Cilento, F.; Mincigrucci, R.; Simoncig, A.; Principi, E.; Masciovecchio, C.; Raimondi, L.; Mahne, N.; Svetina, C.; Zangrando, M.; Passuello, R.; Gaio, G.; Prica, M.; Scarcia, M.; Kourousias, G.; Borghes, R.; Giannessi, L.; Wurth, W.; Parmigiani, F.

    2016-01-01

    In the past few years, we have been witnessing an increased interest for studying materials properties under non-equilibrium conditions. Several well established spectroscopies for experiments in the energy domain have been successfully adapted to the time domain with sub-picosecond time resolution. Here we show the realization of high resolution resonant inelastic X-ray scattering (RIXS) with a stable ultrashort X-ray source such as an externally seeded free electron laser (FEL). We have designed and constructed a RIXS experimental endstation that allowed us to successfully measure the d-d excitations in KCoF3 single crystals at the cobalt M2,3-edge at FERMI FEL (Elettra-Sincrotrone Trieste, Italy). The FEL-RIXS spectra show an excellent agreement with the ones obtained from the same samples at the MERIXS endstation of the MERLIN beamline at the Advanced Light Source storage ring (Berkeley, USA). We established experimental protocols for performing time resolved RIXS experiments at a FEL source to avoid X ray-induced sample damage, while retaining comparable acquisition time to the synchrotron based measurements. Finally, we measured and modelled the influence of the FEL mixed electromagnetic modes, also present in externally seeded FELs, and the beam transport with ~120 meV experimental resolution achieved in the presented RIXS setup. PMID:27941842

  2. Angular correlations of photons from solution diffraction at a free-electron laser encode molecular structure

    SciTech Connect

    Mendez, Derek; Watkins, Herschel; Qiao, Shenglan; Raines, Kevin S.; Lane, Thomas J.; Schenk, Gundolf; Nelson, Garrett; Subramanian, Ganesh; Tono, Kensuke; Joti, Yasumasa; Yabashi, Makina; Ratner, Daniel; Doniach, Sebastian

    2016-09-26

    During X-ray exposure of a molecular solution, photons scattered from the same molecule are correlated. If molecular motion is insignificant during exposure, then differences in momentum transfer between correlated photons are direct measurements of the molecular structure. In conventional small- and wide-angle solution scattering, photon correlations are ignored. This report presents advances in a new biomolecular structural analysis technique, correlated X-ray scattering (CXS), which uses angular intensity correlations to recover hidden structural details from molecules in solution. Due to its intense rapid pulses, an X-ray free electron laser (XFEL) is an excellent tool for CXS experiments. A protocol is outlined for analysis of a CXS data set comprising a total of half a million X-ray exposures of solutions of small gold nanoparticles recorded at the Spring-8 Ångström Compact XFEL facility (SACLA). From the scattered intensities and their correlations, two populations of nanoparticle domains within the solution are distinguished: small twinned, and large probably non-twinned domains. Finally, it is shown analytically how, in a solution measurement, twinning information is only accessible via intensity correlations, demonstrating how CXS reveals atomic-level information from a disordered solution of like molecules.

  3. Design overview of a highly stable infrared free electron laser at LBL

    SciTech Connect

    Kim, K.J.; Berz, M.; Chattopadhyay, S.; Gough, R.; Kim, C.; Kung, A.H.; Xie, M. ); Edighoffer, J. ); Stein, W. )

    1990-11-01

    An infrared free electron laser (IRFEL) is being designed for the Chemical Dynamics Research Laboratory (CDRL) at LBL. The FEL is based on a 50 MeV RF linac operating in synchronization to the Advanced Light Source (ALS), and will produce intense (100 {mu}J per micropulse), narrow bandwidth (narrower than 0.1%) radiation between 3 {mu} and 50 {mu}. In the design, we pay particular attention to the FEL stability issues and require that the fluctuations in electron beam energy and in timing be less then 0.05% and 0.1 ps respectively. The FEL spectrum can then be stabilized to about 10{sup {minus}3}, or if grating is used, to 10{sup {minus}4}. We discuss various sources of fluctuations in the gun, the bunchers and the accelerator sections, as well as the feedback and feedforward schemes to reduce these fluctuations. The accelerator structure is chosen to be of the side coupled, standing wave type for easier control. The beam transport is made isochronous to avoid the coupling between the energy and the timing fluctuations. 12 refs., 1 fig.

  4. Requirements and design of a high stable infrared free electron laser at LBL

    SciTech Connect

    Kim, K.J.; Berz, M.; Chattopadhyay, S.; Gough, R.; Kim, C.; Kung, A.H.; Xie, M. ); Edighoffer, J. ); Stein, W. )

    1990-06-01

    An infrared free electron laser (IRFEL) is being designed for the Chemical Dynamics Research Laboratory (CDRL) at LBL. The FEL is based on a 50 MeV RF linac operating in synchronization to the Advanced Light Source (ALS), and will produce intense (100 {mu}J per micropulse), narrow bandwidth (narrower than 0.1%) radiation between 3 {mu} and 50 {mu}. In the design, we pay particular attention to the FEL stability issues and require that the fluctuations in electron beam energy and in timing be less than 0.05% and 0.1 ps, respectively. The FEL spectrum can then be stabilized to about 10{sup {minus}3}, or if grating is used, to 10{sup {minus}4}. We discuss various sources of fluctuations in the gun, the bunchers and the accelerator sections, as well as the feedback and feedforward schemes to reduce these fluctuations. The accelerator structure is chosen to be of the side coupled, standing wave type for easier control. The beam transport is made isochronous to avoid the coupling between the energy and the timing fluctuations. 9 refs., 2 figs.

  5. An integral equation based computer code for high-gain free-electron lasers

    SciTech Connect

    Dejus, R.J.; Shevchenko, O.A.; Vinokurov, N.A.

    1998-09-01

    A computer code for gain optimization of high-gain free-electron lasers (FELs) is described. The electron motion is along precalculated period-averaged trajectories, and the finite-emittance electron beam is represented by a set of thin partial beams. The radiation field amplitudes are calculated at these thin beams only. The system of linear integral equations for these field amplitudes and the Fourier harmonics of the current of each thin beam is solved numerically. The code is aimed for design optimization of high-gain short-wavelength FELs with nonideal magnetic systems (breaks between undulators with quadrupoles and magnetic bunchers; field and steering errors). Both self-amplified spontaneous emission (SASE) and external input signal options can be treated. A typical run for a UV FEL, several gain lengths long, takes only one minute on a Pentium II personal computer (333 MHz) which makes it possible to run the code in optimization loops. Results for the Advanced Photon Source FEL project are presented.

  6. Angular correlations of photons from solution diffraction at a free-electron laser encode molecular structure

    PubMed Central

    Mendez, Derek; Watkins, Herschel; Qiao, Shenglan; Raines, Kevin S.; Lane, Thomas J.; Schenk, Gundolf; Nelson, Garrett; Subramanian, Ganesh; Tono, Kensuke; Joti, Yasumasa; Yabashi, Makina; Ratner, Daniel; Doniach, Sebastian

    2016-01-01

    During X-ray exposure of a molecular solution, photons scattered from the same molecule are correlated. If molecular motion is insignificant during exposure, then differences in momentum transfer between correlated photons are direct measurements of the molecular structure. In conventional small- and wide-angle solution scattering, photon correlations are ignored. This report presents advances in a new biomolecular structural analysis technique, correlated X-ray scattering (CXS), which uses angular intensity correlations to recover hidden structural details from molecules in solution. Due to its intense rapid pulses, an X-ray free electron laser (XFEL) is an excellent tool for CXS experiments. A protocol is outlined for analysis of a CXS data set comprising a total of half a million X-ray exposures of solutions of small gold nanoparticles recorded at the Spring-8 Ångström Compact XFEL facility (SACLA). From the scattered intensities and their correlations, two populations of nanoparticle domains within the solution are distinguished: small twinned, and large probably non-twinned domains. It is shown analytically how, in a solution measurement, twinning information is only accessible via intensity correlations, demonstrating how CXS reveals atomic-level information from a disordered solution of like molecules. PMID:27840681

  7. Extreme ultraviolet resonant inelastic X-ray scattering (RIXS) at a seeded free-electron laser

    SciTech Connect

    Dell’Angela, M.; Hieke, F.; Malvestuto, M.; Sturari, L.; Bajt, S.; Kozhevnikov, I. V.; Ratanapreechachai, J.; Caretta, A.; Casarin, B.; Glerean, F.; Kalashnikova, A. M.; Pisarev, R. V.; Chuang, Y. -D.; Manzoni, G.; Cilento, F.; Mincigrucci, R.; Simoncig, A.; Principi, E.; Masciovecchio, C.; Raimondi, L.; Mahne, N.; Svetina, C.; Zangrando, M.; Passuello, R.; Gaio, G.; Prica, M.; Scarcia, M.; Kourousias, G.; Borghes, R.; Giannessi, L.; Wurth, W.; Parmigiani, F.

    2016-12-12

    In the past few years, we have been witnessing an increased interest for studying materials properties under non-equilibrium conditions. Several well established spectroscopies for experiments in the energy domain have been successfully adapted to the time domain with sub-picosecond time resolution. Here we show the realization of high resolution resonant inelastic X-ray scattering (RIXS) with a stable ultrashort X-ray source such as an externally seeded free electron laser (FEL). We have designed and constructed a RIXS experimental endstation that allowed us to successfully measure the d-d excitations in KCoF 3 single crystals at the cobalt M 2,3-edge at FERMI FEL (Elettra-Sincrotrone Trieste, Italy). The FEL-RIXS spectra show an excellent agreement with the ones obtained from the same samples at the MERIXS endstation of the MERLIN beamline at the Advanced Light Source storage ring (Berkeley, USA). We established experimental protocols for performing time resolved RIXS experiments at a FEL source to avoid X ray-induced sample damage, while retaining comparable acquisition time to the synchrotron based measurements. Finally, we measured and modelled the influence of the FEL mixed electromagnetic modes, also present in externally seeded FELs, and the beam transport with ~120 meV experimental resolution achieved in the presented RIXS setup.

  8. Angular correlations of photons from solution diffraction at a free-electron laser encode molecular structure

    DOE PAGES

    Mendez, Derek; Watkins, Herschel; Qiao, Shenglan; ...

    2016-09-26

    During X-ray exposure of a molecular solution, photons scattered from the same molecule are correlated. If molecular motion is insignificant during exposure, then differences in momentum transfer between correlated photons are direct measurements of the molecular structure. In conventional small- and wide-angle solution scattering, photon correlations are ignored. This report presents advances in a new biomolecular structural analysis technique, correlated X-ray scattering (CXS), which uses angular intensity correlations to recover hidden structural details from molecules in solution. Due to its intense rapid pulses, an X-ray free electron laser (XFEL) is an excellent tool for CXS experiments. A protocol is outlinedmore » for analysis of a CXS data set comprising a total of half a million X-ray exposures of solutions of small gold nanoparticles recorded at the Spring-8 Ångström Compact XFEL facility (SACLA). From the scattered intensities and their correlations, two populations of nanoparticle domains within the solution are distinguished: small twinned, and large probably non-twinned domains. Finally, it is shown analytically how, in a solution measurement, twinning information is only accessible via intensity correlations, demonstrating how CXS reveals atomic-level information from a disordered solution of like molecules.« less

  9. Angular correlations of photons from solution diffraction at a free-electron laser encode molecular structure.

    PubMed

    Mendez, Derek; Watkins, Herschel; Qiao, Shenglan; Raines, Kevin S; Lane, Thomas J; Schenk, Gundolf; Nelson, Garrett; Subramanian, Ganesh; Tono, Kensuke; Joti, Yasumasa; Yabashi, Makina; Ratner, Daniel; Doniach, Sebastian

    2016-11-01

    During X-ray exposure of a molecular solution, photons scattered from the same molecule are correlated. If molecular motion is insignificant during exposure, then differences in momentum transfer between correlated photons are direct measurements of the molecular structure. In conventional small- and wide-angle solution scattering, photon correlations are ignored. This report presents advances in a new biomolecular structural analysis technique, correlated X-ray scattering (CXS), which uses angular intensity correlations to recover hidden structural details from molecules in solution. Due to its intense rapid pulses, an X-ray free electron laser (XFEL) is an excellent tool for CXS experiments. A protocol is outlined for analysis of a CXS data set comprising a total of half a million X-ray exposures of solutions of small gold nanoparticles recorded at the Spring-8 Ångström Compact XFEL facility (SACLA). From the scattered intensities and their correlations, two populations of nanoparticle domains within the solution are distinguished: small twinned, and large probably non-twinned domains. It is shown analytically how, in a solution measurement, twinning information is only accessible via intensity correlations, demonstrating how CXS reveals atomic-level information from a disordered solution of like molecules.

  10. Extreme ultraviolet resonant inelastic X-ray scattering (RIXS) at a seeded free-electron laser

    NASA Astrophysics Data System (ADS)

    Dell’Angela, M.; Hieke, F.; Malvestuto, M.; Sturari, L.; Bajt, S.; Kozhevnikov, I. V.; Ratanapreechachai, J.; Caretta, A.; Casarin, B.; Glerean, F.; Kalashnikova, A. M.; Pisarev, R. V.; Chuang, Y.-D.; Manzoni, G.; Cilento, F.; Mincigrucci, R.; Simoncig, A.; Principi, E.; Masciovecchio, C.; Raimondi, L.; Mahne, N.; Svetina, C.; Zangrando, M.; Passuello, R.; Gaio, G.; Prica, M.; Scarcia, M.; Kourousias, G.; Borghes, R.; Giannessi, L.; Wurth, W.; Parmigiani, F.

    2016-12-01

    In the past few years, we have been witnessing an increased interest for studying materials properties under non-equilibrium conditions. Several well established spectroscopies for experiments in the energy domain have been successfully adapted to the time domain with sub-picosecond time resolution. Here we show the realization of high resolution resonant inelastic X-ray scattering (RIXS) with a stable ultrashort X-ray source such as an externally seeded free electron laser (FEL). We have designed and constructed a RIXS experimental endstation that allowed us to successfully measure the d-d excitations in KCoF3 single crystals at the cobalt M2,3-edge at FERMI FEL (Elettra-Sincrotrone Trieste, Italy). The FEL-RIXS spectra show an excellent agreement with the ones obtained from the same samples at the MERIXS endstation of the MERLIN beamline at the Advanced Light Source storage ring (Berkeley, USA). We established experimental protocols for performing time resolved RIXS experiments at a FEL source to avoid X ray-induced sample damage, while retaining comparable acquisition time to the synchrotron based measurements. Finally, we measured and modelled the influence of the FEL mixed electromagnetic modes, also present in externally seeded FELs, and the beam transport with ~120 meV experimental resolution achieved in the presented RIXS setup.

  11. Structural biology at the European X-ray free-electron laser facility.

    PubMed

    Altarelli, Massimo; Mancuso, Adrian P

    2014-07-17

    The European X-ray free-electron laser (XFEL) facility, under construction in the Hamburg region, will provide high-peak brilliance (greater than 10(33) photons s(-1) mm(-2) mrad(-2) per 0.1% BW), ultrashort pulses (approx. 10 fs) of X-rays, with a high repetition rate (up to 27 000 pulses s(-1)) from 2016 onwards. The main features of this exceptional X-ray source, and the instrumentation developments necessary to exploit them fully, for application to a variety of scientific disciplines, are briefly summarized. In the case of structural biology, that has a central role in the scientific case of this new facility, the instruments and ancillary laboratories that are being planned and built within the baseline programme of the European XFEL and by consortia of users are also discussed. It is expected that the unique features of the source and the advanced features of the instrumentation will allow operation modes with more efficient use of sample materials, faster acquisition times, and conditions better approaching feasibility of single molecule imaging.

  12. Structural biology at the European X-ray free-electron laser facility

    PubMed Central

    Altarelli, Massimo; Mancuso, Adrian P.

    2014-01-01

    The European X-ray free-electron laser (XFEL) facility, under construction in the Hamburg region, will provide high-peak brilliance (greater than 1033 photons s−1 mm−2 mrad−2 per 0.1% BW), ultrashort pulses (approx. 10 fs) of X-rays, with a high repetition rate (up to 27 000 pulses s−1) from 2016 onwards. The main features of this exceptional X-ray source, and the instrumentation developments necessary to exploit them fully, for application to a variety of scientific disciplines, are briefly summarized. In the case of structural biology, that has a central role in the scientific case of this new facility, the instruments and ancillary laboratories that are being planned and built within the baseline programme of the European XFEL and by consortia of users are also discussed. It is expected that the unique features of the source and the advanced features of the instrumentation will allow operation modes with more efficient use of sample materials, faster acquisition times, and conditions better approaching feasibility of single molecule imaging. PMID:24914145

  13. The VUV/IR/THz Free Electron Laser Program at Jefferson Lab

    SciTech Connect

    Benson, S V; Boyce, J R; Douglas, D R; Evtushenko, P; Hannon, F E; Hernandez-Garcia, C; Klopf, J M; Neil, G R; Shinn, Michelle D; Tennant, C D; Zhang, S; Williams, G P

    2011-09-01

    Jefferson Lab operates a pair of oscillator-based continuous-wave Free Electron Lasers (FELs) as a linac-based next generation light source with pulse repetition rates up to 75 MHz. The facility uses an energy recovered linac design for efficiency of operation. Recent advances in superconducting technology have been implemented to produce higher acceleration gradients in the linac to produce higher electron beam energies that result in higher photon energies. Thus, while the system originally operated only in the IR, it now covers the photon energy range from the UV to THz, with harmonics upwards of 10 eV with an average spectral flux that is calculated to be 5x1017 photons/sec/0.1%BW. Pulse lengths are in the sub-picosecond regime, and the fully coherent nature of the source, both transversely and longitudinally, results in peak and average brightness values that are several orders of magnitude higher than storage rings. The system provides an R&D test-bed for studies of electron beam dynamics in a regime appropriate for next generation light sources operating at MHz repetition rates.

  14. Extreme ultraviolet resonant inelastic X-ray scattering (RIXS) at a seeded free-electron laser

    DOE PAGES

    Dell’Angela, M.; Hieke, F.; Malvestuto, M.; ...

    2016-12-12

    In the past few years, we have been witnessing an increased interest for studying materials properties under non-equilibrium conditions. Several well established spectroscopies for experiments in the energy domain have been successfully adapted to the time domain with sub-picosecond time resolution. Here we show the realization of high resolution resonant inelastic X-ray scattering (RIXS) with a stable ultrashort X-ray source such as an externally seeded free electron laser (FEL). We have designed and constructed a RIXS experimental endstation that allowed us to successfully measure the d-d excitations in KCoF 3 single crystals at the cobalt M 2,3-edge at FERMI FELmore » (Elettra-Sincrotrone Trieste, Italy). The FEL-RIXS spectra show an excellent agreement with the ones obtained from the same samples at the MERIXS endstation of the MERLIN beamline at the Advanced Light Source storage ring (Berkeley, USA). We established experimental protocols for performing time resolved RIXS experiments at a FEL source to avoid X ray-induced sample damage, while retaining comparable acquisition time to the synchrotron based measurements. Finally, we measured and modelled the influence of the FEL mixed electromagnetic modes, also present in externally seeded FELs, and the beam transport with ~120 meV experimental resolution achieved in the presented RIXS setup.« less

  15. STUDIES OF A FREE ELECTRON LASER DRIVEN BY A LASER-PLASMA ACCELERATOR

    SciTech Connect

    Montgomery, A.; Schroeder, C.; Fawley, W.

    2008-01-01

    A free electron laser (FEL) uses an undulator, a set of alternating magnets producing a periodic magnetic fi eld, to stimulate emission of coherent radiation from a relativistic electron beam. The Lasers, Optical Accelerator Systems Integrated Studies (LOASIS) group at Lawrence Berkeley National Laboratory (LBNL) will use an innovative laserplasma wakefi eld accelerator to produce an electron beam to drive a proposed FEL. In order to optimize the FEL performance, the dependence on electron beam and undulator parameters must be understood. Numerical modeling of the FEL using the simulation code GINGER predicts the experimental results for given input parameters. Among the parameters studied were electron beam energy spread, emittance, and mismatch with the undulator focusing. Vacuum-chamber wakefi elds were also simulated to study their effect on FEL performance. Energy spread was found to be the most infl uential factor, with output FEL radiation power sharply decreasing for relative energy spreads greater than 0.33%. Vacuum chamber wakefi elds and beam mismatch had little effect on the simulated LOASIS FEL at the currents considered. This study concludes that continued improvement of the laser-plasma wakefi eld accelerator electron beam will allow the LOASIS FEL to operate in an optimal regime, producing high-quality XUV and x-ray pulses.

  16. Spatio-temporal coherence of free-electron laser radiation in the extreme ultraviolet determined by a Michelson interferometer

    NASA Astrophysics Data System (ADS)

    Hilbert, V.; Rödel, C.; Brenner, G.; Döppner, T.; Düsterer, S.; Dziarzhytski, S.; Fletcher, L.; Förster, E.; Glenzer, S. H.; Harmand, M.; Hartley, N. J.; Kazak, L.; Komar, D.; Laarmann, T.; Lee, H. J.; Ma, T.; Nakatsutsumi, M.; Przystawik, A.; Redlin, H.; Skruszewicz, S.; Sperling, P.; Tiggesbäumker, J.; Toleikis, S.; Zastrau, U.

    2014-09-01

    A key feature of extreme ultraviolet (XUV) radiation from free-electron lasers (FELs) is its spatial and temporal coherence. We measured the spatio-temporal coherence properties of monochromatized FEL pulses at 13.5 nm using a Michelson interferometer. A temporal coherence time of (59±8) fs has been determined, which is in good agreement with the spectral bandwidth given by the monochromator. Moreover, the spatial coherence in vertical direction amounts to about 15% of the beam diameter and about 12% in horizontal direction. The feasibility of measuring spatio-temporal coherence properties of XUV FEL radiation using interferometric techniques advances machine operation and experimental studies significantly.

  17. Spatio-temporal coherence of free-electron laser radiation in the extreme ultraviolet determined by a Michelson interferometer

    SciTech Connect

    Hilbert, V.; Rödel, C.; Zastrau, U.; Brenner, G.; Düsterer, S.; Dziarzhytski, S.; Harmand, M.; Przystawik, A.; Redlin, H.; Toleikis, S.; Döppner, T.; Ma, T.; Fletcher, L.; Förster, E.; Glenzer, S. H.; Lee, H. J.; Hartley, N. J.; Kazak, L.; Komar, D.; Skruszewicz, S.; and others

    2014-09-08

    A key feature of extreme ultraviolet (XUV) radiation from free-electron lasers (FELs) is its spatial and temporal coherence. We measured the spatio-temporal coherence properties of monochromatized FEL pulses at 13.5 nm using a Michelson interferometer. A temporal coherence time of (59±8) fs has been determined, which is in good agreement with the spectral bandwidth given by the monochromator. Moreover, the spatial coherence in vertical direction amounts to about 15% of the beam diameter and about 12% in horizontal direction. The feasibility of measuring spatio-temporal coherence properties of XUV FEL radiation using interferometric techniques advances machine operation and experimental studies significantly.

  18. Sequential Single Shot X-ray Photon Correlation Spectroscopy at the SACLA Free Electron Laser

    PubMed Central

    Lehmkühler, Felix; Kwaśniewski, Paweł; Roseker, Wojciech; Fischer, Birgit; Schroer, Martin A.; Tono, Kensuke; Katayama, Tetsuo; Sprung, Michael; Sikorski, Marcin; Song, Sanghoon; Glownia, James; Chollet, Matthieu; Nelson, Silke; Robert, Aymeric; Gutt, Christian; Yabashi, Makina; Ishikawa, Tetsuya; Grübel, Gerhard

    2015-01-01

    Hard X-ray free electron lasers allow for the first time to access dynamics of condensed matter samples ranging from femtoseconds to several hundred seconds. In particular, the exceptional large transverse coherence of the X-ray pulses and the high time-averaged flux promises to reach time and length scales that have not been accessible up to now with storage ring based sources. However, due to the fluctuations originating from the stochastic nature of the self-amplified spontaneous emission (SASE) process the application of well established techniques such as X-ray photon correlation spectroscopy (XPCS) is challenging. Here we demonstrate a single-shot based sequential XPCS study on a colloidal suspension with a relaxation time comparable to the SACLA free-electron laser pulse repetition rate. High quality correlation functions could be extracted without any indications for sample damage. This opens the way for systematic sequential XPCS experiments at FEL sources. PMID:26610328

  19. Nanofocusing of X-ray free-electron lasers by grazing-incidence reflective optics

    PubMed Central

    Yamauchi, Kazuto; Yabashi, Makina; Ohashi, Haruhiko; Koyama, Takahisa; Ishikawa, Tetsuya

    2015-01-01

    Total-reflection mirror devices for X-ray free-electron laser focusing are discussed in terms of optical design, mirror-fabrication technology, a wavefront diagnosis method and radiation-damage testing, as a review of the present status of the focusing optics at the SPring-8 angstrom compact free-electron laser (SACLA). Designed beam sizes of 1 µm and 50 nm, and spot sizes almost matching prediction have been achieved and used to explore topics at the forefront of natural science. The feasibility of these devices is determined to be sufficient for long-term and stable operation at SACLA by investigating the radiation-damage threshold and achievable accuracies in the mirror figure and alignment. PMID:25931073

  20. Exponential gain and saturation of a self-amplified spontaneous emission free-electron laser.

    PubMed

    Milton, S V; Gluskin, E; Arnold, N D; Benson, C; Berg, W; Biedron, S G; Borland, M; Chae, Y C; Dejus, R J; Den Hartog, P K; Deriy, B; Erdmann, M; Eidelman, Y I; Hahne, M W; Huang, Z; Kim, K J; Lewellen, J W; Li, Y; Lumpkin, A H; Makarov, O; Moog, E R; Nassiri, A; Sajaev, V; Soliday, R; Tieman, B J; Trakhtenberg, E M; Travish, G; Vasserman, I B; Vinokurov, N A; Wang, X J; Wiemerslage, G; Yang, B X

    2001-06-15

    Self-amplified spontaneous emission in a free-electron laser has been proposed for the generation of very high brightness coherent x-rays. This process involves passing a high-energy, high-charge, short-pulse, low-energy-spread, and low-emittance electron beam through the periodic magnetic field of a long series of high-quality undulator magnets. The radiation produced grows exponentially in intensity until it reaches a saturation point. We report on the demonstration of self-amplified spontaneous emission gain, exponential growth, and saturation at visible (530 nanometers) and ultraviolet (385 nanometers) wavelengths. Good agreement between theory and simulation indicates that scaling to much shorter wavelengths may be possible. These results confirm the physics behind the self-amplified spontaneous emission process and forward the development of an operational x-ray free-electron laser.

  1. Few-femtosecond time-resolved measurements of X-ray free-electron lasers.

    PubMed

    Behrens, C; Decker, F-J; Ding, Y; Dolgashev, V A; Frisch, J; Huang, Z; Krejcik, P; Loos, H; Lutman, A; Maxwell, T J; Turner, J; Wang, J; Wang, M-H; Welch, J; Wu, J

    2014-04-30

    X-ray free-electron lasers, with pulse durations ranging from a few to several hundred femtoseconds, are uniquely suited for studying atomic, molecular, chemical and biological systems. Characterizing the temporal profiles of these femtosecond X-ray pulses that vary from shot to shot is not only challenging but also important for data interpretation. Here we report the time-resolved measurements of X-ray free-electron lasers by using an X-band radiofrequency transverse deflector at the Linac Coherent Light Source. We demonstrate this method to be a simple, non-invasive technique with a large dynamic range for single-shot electron and X-ray temporal characterization. A resolution of less than 1 fs root mean square has been achieved for soft X-ray pulses. The lasing evolution along the undulator has been studied with the electron trapping being observed as the X-ray peak power approaches 100 GW.

  2. Claudio Pellegrini and the World’s First Hard X-ray Free-Electron Laser

    SciTech Connect

    Pellegrini, Claudio

    2015-10-20

    President Obama welcomed SLAC's Claudio Pellegrini inside the Oval Office on Tuesday morning as a recipient of the Enrico Fermi Award, one of the highest honors the U.S. government can give to a scientist. Pellegrini, a visiting scientist and consulting professor at SLAC and distinguished professor emeritus at the University of California, Los Angeles, received the award for research that aided in the development of X-ray free-electron lasers (XFELs) including SLAC's Linac Coherent Light Source (LCLS), a DOE Office of Science User Facility that started up in 2009. Here, Pellegrini describes his efforts that contributed to the realization of SLAC’s Linac Coherent Light Source, the world’s first hard X-ray free-electron laser.

  3. An extreme ultraviolet Michelson interferometer for experiments at free-electron lasers.

    PubMed

    Hilbert, Vinzenz; Blinne, Alexander; Fuchs, Silvio; Feigl, Torsten; Kämpfer, Tino; Rödel, Christian; Uschmann, Ingo; Wünsche, Martin; Paulus, Gerhard G; Förster, Eckhart; Zastrau, Ulf

    2013-09-01

    We present a Michelson interferometer for 13.5 nm soft x-ray radiation. It is characterized in a proof-of-principle experiment using synchrotron radiation, where the temporal coherence is measured to be 13 fs. The curvature of the thin-film beam splitter membrane is derived from the observed fringe pattern. The applicability of this Michelson interferometer at intense free-electron lasers is investigated, particularly with respect to radiation damage. This study highlights the potential role of such Michelson interferometers in solid density plasma investigations using, for instance, extreme soft x-ray free-electron lasers. A setup using the Michelson interferometer for pseudo-Nomarski-interferometry is proposed.

  4. Femtosecond X-ray Pulse Temporal Characterization in Free-Electron Lasers Using a Transverse Deflector

    SciTech Connect

    Ding, Y.; Behrens, C.; Emma, P.; Frisch, J.; Huang, Z.; Loos, H.; Krejcik, P.; Wang, M-H.; /SLAC

    2011-12-13

    We propose a novel method to characterize the temporal duration and shape of femtosecond x-ray pulses in a free-electron laser (FEL) by measuring the time-resolved electron-beam energy loss and energy spread induced by the FEL process, with a transverse radio-frequency deflector located after the undulator. Its merits are simplicity, high resolution, wide diagnostic range, and non-invasive to user operation. When the system is applied to the Linac Coherent Light Source, the first hard x-ray free-electron laser in the world, it can provide single-shot measurements on the electron beam and x-ray pulses with a resolution on the order of 1-2 femtoseconds rms.

  5. Nanofocusing of X-ray free-electron lasers by grazing-incidence reflective optics.

    PubMed

    Yamauchi, Kazuto; Yabashi, Makina; Ohashi, Haruhiko; Koyama, Takahisa; Ishikawa, Tetsuya

    2015-05-01

    Total-reflection mirror devices for X-ray free-electron laser focusing are discussed in terms of optical design, mirror-fabrication technology, a wavefront diagnosis method and radiation-damage testing, as a review of the present status of the focusing optics at the SPring-8 angstrom compact free-electron laser (SACLA). Designed beam sizes of 1 µm and 50 nm, and spot sizes almost matching prediction have been achieved and used to explore topics at the forefront of natural science. The feasibility of these devices is determined to be sufficient for long-term and stable operation at SACLA by investigating the radiation-damage threshold and achievable accuracies in the mirror figure and alignment.

  6. Explicit approximations for strictly nonlinear oscillators with slowly varying parameters with applications to free electron lasers

    NASA Astrophysics Data System (ADS)

    Kevorkian, J.; Li, Y. P.

    1987-08-01

    The first part of this paper summarizes the mathematical modeling of free electron lasers (FEL), and the remainder concerns general perturbation methods for solving free electron laser (FEL) and other strictly nonlinear oscillatory problems with slowly varying parameters and small perturbations. We review and compare the methods of Kuzmak-Luke and of near-identity averaging transformations. In order to implement the calculation of explicit solutions we develop two approximation schemes. The first involves use of finite Fourier series to present either the leading approximation of the solution or the transformation of the governing equations to a standard form appropriate for the method of averaging. In the second scheme we fit a cubic polynomial to the potential such that the leading approximation is expressible in terms of elliptic functions. The ideas are illustrated with a number of examples which are also solved numerically to assess the accuracy of the various approximations.

  7. Next-generation materials for future synchrotron and free-electron laser sources

    DOE PAGES

    Assoufid, Lahsen; Graafsma, Heinz

    2017-06-09

    We show that the development of new materials and improvements of existing ones are at the root of the spectacular recent developments of new technologies for synchrotron storage rings and free-electron laser sources. This holds true for all relevant application areas, from electron guns to undulators, x-ray optics, and detectors. As demand grows for more powerful and efficient light sources, efficient optics, and high-speed detectors, an overview of ongoing materials research for these applications is timely. In this article, we focus on the most exciting and demanding areas of materials research and development for synchrotron radiation optics and detectors. Materialsmore » issues of components for synchrotron and free-electron laser accelerators are briefly discussed. Lastly, the articles in this issue expand on these topics.« less

  8. Effect of an angular trajectory kick in a high-gain free-electron laser

    NASA Astrophysics Data System (ADS)

    Baxevanis, Panagiotis; Huang, Zhirong; Stupakov, Gennady

    2017-04-01

    In a free-electron laser, a transverse momentum offset (or "kick") results in an oscillation of the centroid of the electron beam about the undulator axis. Studying the influence of this effect on the free-electron laser (FEL) interaction is important both from a tolerance point of view and for its potential diagnostic applications. In this paper, we present a self-consistent theoretical analysis of a high-gain FEL driven by such a "kicked" beam. In particular, we derive a solution to the three-dimensional, linearized initial value problem of the FEL through an orthogonal expansion technique and also describe a variational method for calculating the average FEL growth rate. Our results are benchmarked with genesis simulations and provide a robust theoretical background for a comparison with previous analytical results.

  9. Sequential Single Shot X-ray Photon Correlation Spectroscopy at the SACLA Free Electron Laser.

    PubMed

    Lehmkühler, Felix; Kwaśniewski, Paweł; Roseker, Wojciech; Fischer, Birgit; Schroer, Martin A; Tono, Kensuke; Katayama, Tetsuo; Sprung, Michael; Sikorski, Marcin; Song, Sanghoon; Glownia, James; Chollet, Matthieu; Nelson, Silke; Robert, Aymeric; Gutt, Christian; Yabashi, Makina; Ishikawa, Tetsuya; Grübel, Gerhard

    2015-11-27

    Hard X-ray free electron lasers allow for the first time to access dynamics of condensed matter samples ranging from femtoseconds to several hundred seconds. In particular, the exceptional large transverse coherence of the X-ray pulses and the high time-averaged flux promises to reach time and length scales that have not been accessible up to now with storage ring based sources. However, due to the fluctuations originating from the stochastic nature of the self-amplified spontaneous emission (SASE) process the application of well established techniques such as X-ray photon correlation spectroscopy (XPCS) is challenging. Here we demonstrate a single-shot based sequential XPCS study on a colloidal suspension with a relaxation time comparable to the SACLA free-electron laser pulse repetition rate. High quality correlation functions could be extracted without any indications for sample damage. This opens the way for systematic sequential XPCS experiments at FEL sources.

  10. An extreme ultraviolet Michelson interferometer for experiments at free-electron lasers

    NASA Astrophysics Data System (ADS)

    Hilbert, Vinzenz; Blinne, Alexander; Fuchs, Silvio; Feigl, Torsten; Kämpfer, Tino; Rödel, Christian; Uschmann, Ingo; Wünsche, Martin; Paulus, Gerhard G.; Förster, Eckhart; Zastrau, Ulf

    2013-09-01

    We present a Michelson interferometer for 13.5 nm soft x-ray radiation. It is characterized in a proof-of-principle experiment using synchrotron radiation, where the temporal coherence is measured to be 13 fs. The curvature of the thin-film beam splitter membrane is derived from the observed fringe pattern. The applicability of this Michelson interferometer at intense free-electron lasers is investigated, particularly with respect to radiation damage. This study highlights the potential role of such Michelson interferometers in solid density plasma investigations using, for instance, extreme soft x-ray free-electron lasers. A setup using the Michelson interferometer for pseudo-Nomarski-interferometry is proposed.

  11. Effect of an angular trajectory kick in a high-gain free-electron laser

    DOE PAGES

    Baxevanis, Panagiotis; Huang, Zhirong; Stupakov, Gennady

    2017-04-18

    In a free-electron laser, a transverse momentum offset (or “kick”) results in an oscillation of the centroid of the electron beam about the undulator axis. Studying the influence of this effect on the free-electron laser (FEL) interaction is important both from a tolerance point of view and for its potential diagnostic applications. In this paper, we present a self-consistent theoretical analysis of a high-gain FEL driven by such a “kicked” beam. In particular, we derive a solution to the three-dimensional, linearized initial value problem of the FEL through an orthogonal expansion technique and also describe a variational method for calculatingmore » the average FEL growth rate. Lastly, our results are benchmarked with genesis simulations and provide a robust theoretical background for a comparison with previous analytical results.« less

  12. A tunable optical cavity for an x-ray free-electron laser oscillator.

    SciTech Connect

    Kim, K.-J.; Shvyd'ko, Y.

    2009-03-01

    An x-ray free-electron laser oscillator proposed recently for hard x rays [K. Kim, Y. Shvydko, and S. Reiche, Phys. Rev. Lett. 100, 244802 (2008)] can be made tunable by using an x-ray cavity composed of four crystals, instead of two. The tunability of x-ray energy will significantly enhance the usefulness of an x-ray free-electron laser oscillator. We present a detailed analysis of the four-crystal optical cavity and choice of crystals for several applications: inelastic x-ray scattering, nuclear resonant scattering, bulk-sensitive hard x-ray photoemission spectroscopy, other high-energy-resolution ({le} 1 meV) spectroscopic probes, and for imaging with hard x rays at near-atomic resolution ({approx} 1 nm).

  13. Sequential single shot X-ray photon correlation spectroscopy at the SACLA free electron laser

    SciTech Connect

    Lehmkühler, Felix; Kwaśniewski, Paweł; Roseker, Wojciech; Fischer, Birgit; Schroer, Martin A.; Tono, Kensuke; Katayama, Tetsuo; Sprung, Michael; Sikorski, Marcin; Song, Sanghoon; Glownia, James; Chollet, Matthieu; Nelson, Silke; Robert, Aymeric; Gutt, Christian; Yabashi, Makina; Ishikawa, Tetsuya; Grübel, Gerhard

    2015-11-27

    In this study, hard X-ray free electron lasers allow for the first time to access dynamics of condensed matter samples ranging from femtoseconds to several hundred seconds. In particular, the exceptional large transverse coherence of the X-ray pulses and the high time-averaged flux promises to reach time and length scales that have not been accessible up to now with storage ring based sources. However, due to the fluctuations originating from the stochastic nature of the self-amplified spontaneous emission (SASE) process the application of well established techniques such as X-ray photon correlation spectroscopy (XPCS) is challenging. Here we demonstrate a single-shot based sequential XPCS study on a colloidal suspension with a relaxation time comparable to the SACLA free-electron laser pulse repetition rate. High quality correlation functions could be extracted without any indications for sample damage. This opens the way for systematic sequential XPCS experiments at FEL sources.

  14. An extreme ultraviolet Michelson interferometer for experiments at free-electron lasers

    SciTech Connect

    Hilbert, Vinzenz; Fuchs, Silvio; Paulus, Gerhard G.; Zastrau, Ulf; Blinne, Alexander; Feigl, Torsten; Kämpfer, Tino; Rödel, Christian; Uschmann, Ingo; Wünsche, Martin; Förster, Eckhart

    2013-09-15

    We present a Michelson interferometer for 13.5 nm soft x-ray radiation. It is characterized in a proof-of-principle experiment using synchrotron radiation, where the temporal coherence is measured to be 13 fs. The curvature of the thin-film beam splitter membrane is derived from the observed fringe pattern. The applicability of this Michelson interferometer at intense free-electron lasers is investigated, particularly with respect to radiation damage. This study highlights the potential role of such Michelson interferometers in solid density plasma investigations using, for instance, extreme soft x-ray free-electron lasers. A setup using the Michelson interferometer for pseudo-Nomarski-interferometry is proposed.

  15. Chorus wave amplification: A free electron laser in the Earth's magnetosphere

    SciTech Connect

    Soto-Chavez, A. R.; Bhattacharjee, A.; Ng, C. S.

    2012-01-15

    A new theoretical model for whistler-mode chorus amplification in the Earth's magnetosphere is presented. We derive, based on the free-electron laser mechanism in a high-gain amplifier, a new closed set of self-consistent relativistic equations that couple the Hamiltonian equations for particles with Maxwell's equations. We demonstrate that these equations predict, through a cubic equation, whistler amplification levels in good agreement with those observed in the Earth's magnetosphere.

  16. Self-amplified spontaneous emission for a single pass free-electron laser

    NASA Astrophysics Data System (ADS)

    Giannessi, L.; Alesini, D.; Antici, P.; Bacci, A.; Bellaveglia, M.; Boni, R.; Boscolo, M.; Briquez, F.; Castellano, M.; Catani, L.; Chiadroni, E.; Cianchi, A.; Ciocci, F.; Clozza, A.; Couprie, M. E.; Cultrera, L.; Dattoli, G.; Del Franco, M.; Dipace, A.; di Pirro, G.; Doria, A.; Drago, A.; Fawley, W. M.; Ferrario, M.; Ficcadenti, L.; Filippetto, D.; Frassetto, F.; Freund, H. P.; Fusco, V.; Gallerano, G.; Gallo, A.; Gatti, G.; Ghigo, A.; Giovenale, E.; Marinelli, A.; Labat, M.; Marchetti, B.; Marcus, G.; Marrelli, C.; Mattioli, M.; Migliorati, M.; Moreno, M.; Mostacci, A.; Orlandi, G.; Pace, E.; Palumbo, L.; Petralia, A.; Petrarca, M.; Petrillo, V.; Poletto, L.; Quattromini, M.; Rau, J. V.; Reiche, S.; Ronsivalle, C.; Rosenzweig, J.; Rossi, A. R.; Rossi Albertini, V.; Sabia, E.; Serafini, L.; Serluca, M.; Spassovsky, I.; Spataro, B.; Surrenti, V.; Vaccarezza, C.; Vescovi, M.; Vicario, C.

    2011-06-01

    SPARC (acronym of “Sorgente Pulsata ed Amplificata di Radiazione Coerente”, i.e. Pulsed and Amplified Source of Coherent Radiation) is a single pass free-electron laser designed to obtain high gain amplification at a radiation wavelength of 500 nm. Self-amplified spontaneous emission has been observed driving the amplifier with the high-brightness beam of the SPARC linac. We report measurements of energy, spectra, and exponential gain. Experimental results are compared with simulations from several numerical codes.

  17. Megawatt Class Free Electron Lasers for Naval Application - Short Rayleigh Length and Stability Analysis

    DTIC Science & Technology

    2002-12-01

    wavelength λ0 magnetic period length η wiggler extraction efficiency ηrf accelerator efficiency Ω pulse repetition frequency φ... red path in Figure 2. 8 Figure 2. Oscillator Type Free Electron Laser with Energy Recovery in a Ring Configuration Many electrons are...d)]: Undulator Length L 60 cm Number of Magnetic Periods N 20 Magnetic Period Length λ0 3.7 cm Magnetic Field Strength Bu 1 T Wiggler

  18. Reflection Matrix for Optical Resonators in FEL (Free Electron Lasers) Oscillators

    DTIC Science & Technology

    1988-09-22

    is the dominant factor determining the reflction coefficient. The effects of deflecting tho’ light beam enter as small corrections, of first order in...RESONATORS IN FEL OSCILLATORS I. INTRODUCTION 1-7 Free Electron Lasers (FEL) operating as oscillators require the 8-10 trapping of light pulses between...The simplest oscillator configuration is that of an open resonator with two opposed identical mirrors. The radiation vector potential for this

  19. Calculations of the self-amplified spontaneous emission performance of a free-electron laser.

    SciTech Connect

    Dejus, R. J.

    1999-04-20

    The linear integral equation based computer code (RON: Roger Oleg Nikolai), which was recently developed at Argonne National Laboratory, was used to calculate the self-amplified spontaneous emission (SASE) performance of the free-electron laser (FEL) being built at Argonne. Signal growth calculations under different conditions are used for estimating tolerances of actual design parameters. The radiation characteristics are discussed, and calculations using an ideal undulator magnetic field and a real measured magnetic field will be compared and discussed.

  20. Single-particle dynamics of a free-electron laser with axial field

    SciTech Connect

    Pandya, T.P.; Bali, L.M.; Bakshi, U.; Jha, P.

    1987-06-15

    Single-particle dynamics of electron motion through a free-electron-laser cavity with axial guide field is presented. Equations governing the trajectories in the absence of radiation are obtained, and significant departures from the results of earlier work are discussed. Linearized gain in the presence of radiation is derived. Comparison with previous studies reveals (i) good agreement with results and (ii) gain enhancements at hitherto unreported frequencies.

  1. Advection-Induced Spectrotemporal Defects in a Free-Electron Laser

    SciTech Connect

    Bielawski, S.; Szwaj, C.; Bruni, C.; Garzella, D.; Orlandi, G.L.; Couprie, M.E.

    2005-07-15

    We evidence numerically and experimentally that advection can induce spectrotemporal defects in a system presenting a localized structure. Those defects in the spectrum are associated with the breakings induced by the drift of the localized solution. The results are based on simulations and experiments performed on the super-ACO free-electron laser. However, we show that this instability can be generalized using a real Ginzburg-Landau equation with (i) advection and (ii) a finite-size supercritical region.

  2. Data acquisition system for X-ray free-electron laser experiments at SACLA.

    PubMed

    Joti, Yasumasa; Kameshima, Takashi; Yamaga, Mitsuhiro; Sugimoto, Takashi; Okada, Kensuke; Abe, Toshinori; Furukawa, Yukito; Ohata, Toru; Tanaka, Ryotaro; Hatsui, Takaki; Yabashi, Makina

    2015-05-01

    A data acquisition system for X-ray free-electron laser experiments at SACLA has been developed. The system has been designed for reliable shot-to-shot data storage with a high data stream greater than 4 Gbps and massive data analysis. Configuration of the system and examples of prompt data analysis during experiments are presented. Upgrade plans for the system to extend flexibility are described.

  3. Cyclotron auto resonance maser and free electron laser devices: a unified point of view

    NASA Astrophysics Data System (ADS)

    di Palma, E.; Sabia, E.; Dattoli, G.; Licciardi, S.; Spassovsky, I.

    2017-02-01

    We take advantage of previous research in the field of cyclotron auto resonance maser (CARM) and undulator-based free electron laser (U-FEL) sources to establish a common formalism for the relevant description of the underlying physical mechanisms. This strategy is aimed at stressing the deep analogies between the two devices and at providing a practical tool for their study based on the use of well-tested scaling formulae developed independently for the two systems.

  4. Accurate macromolecular structures using minimal measurements from X-ray free-electron lasers.

    PubMed

    Hattne, Johan; Echols, Nathaniel; Tran, Rosalie; Kern, Jan; Gildea, Richard J; Brewster, Aaron S; Alonso-Mori, Roberto; Glöckner, Carina; Hellmich, Julia; Laksmono, Hartawan; Sierra, Raymond G; Lassalle-Kaiser, Benedikt; Lampe, Alyssa; Han, Guangye; Gul, Sheraz; DiFiore, Dörte; Milathianaki, Despina; Fry, Alan R; Miahnahri, Alan; White, William E; Schafer, Donald W; Seibert, M Marvin; Koglin, Jason E; Sokaras, Dimosthenis; Weng, Tsu-Chien; Sellberg, Jonas; Latimer, Matthew J; Glatzel, Pieter; Zwart, Petrus H; Grosse-Kunstleve, Ralf W; Bogan, Michael J; Messerschmidt, Marc; Williams, Garth J; Boutet, Sébastien; Messinger, Johannes; Zouni, Athina; Yano, Junko; Bergmann, Uwe; Yachandra, Vittal K; Adams, Paul D; Sauter, Nicholas K

    2014-05-01

    X-ray free-electron laser (XFEL) sources enable the use of crystallography to solve three-dimensional macromolecular structures under native conditions and without radiation damage. Results to date, however, have been limited by the challenge of deriving accurate Bragg intensities from a heterogeneous population of microcrystals, while at the same time modeling the X-ray spectrum and detector geometry. Here we present a computational approach designed to extract meaningful high-resolution signals from fewer diffraction measurements.

  5. Exactly solvable nonlinear model for a Smith-Purcell free-electron laser

    NASA Astrophysics Data System (ADS)

    Crowne, F. J.; Leavitt, R. P.; Worchesky, T. L.

    1981-08-01

    A model is presented for a Smith-Purcell free-electron laser, including nonlinear effects, that can be solved in closed form. The model is shown to obey the pendulum equation. The average electron efficiency calculated by means of this model is compared with that obtained from an exact numerical calculation and from a simpler 'phase-space' model for a wide range of physical parameters.

  6. Generation of THz Radiation by Excitation of InAs with a Free Electron Laser

    SciTech Connect

    Mashiko Tani; Shunsuke Kono; Ping Gu; Kiyomi Sakai; Mamoru Usami; Michelle D. Shinn; Joseph F. Gubeli; George Neil; Jingzhou Xu; Roland Kersting; X.-C. Zhang

    2001-01-01

    Terahertz (THz) radiation is generated by exciting an un-doped InAs wafer with a femtosecond free-electron laser (FEL) at the Thomas Jefferson National Accelerator Facility. A microwatt level of THz radiation is detected from the unbiased InAs emitter when it is excited with the femtosecond FEL pulses operated at a wavelength of 1.06 {mu}-m and 10 W average power.

  7. Visualizing a protein quake with time resolved X-ray scattering at a free electron laser

    PubMed Central

    Arnlund, David; Johansson, Linda C.; Wickstrand, Cecilia; Barty, Anton; Williams, Garth J.; Malmerberg, Erik; Davidsson, Jan; Milathianaki, Despina; DePonte, Daniel P.; Shoeman, Robert L.; Wang, Dingjie; James, Daniel; Katona, Gergely; Westenhoff, Sebastian; White, Thomas A.; Aquila, Andrew; Bari, Sadia; Berntsen, Peter; Bogan, Mike; van Driel, Tim Brandt; Doak, R. Bruce; Kjær, Kasper Skov; Frank, Matthias; Fromme, Raimund; Grotjohann, Ingo; Henning, Robert; Hunter, Mark S.; Kirian, Richard A.; Kosheleva, Irina; Kupitz, Christopher; Liang, Mengning; Martin, Andrew V.; Nielsen, Martin Meedom; Messerschmidt, Marc; Seibert, M. Marvin; Sjöhamn, Jennie; Stellato, Francesco; Weierstall, Uwe; Zatsepin, Nadia A.; Spence, John C. H.; Fromme, Petra; Schlichting, Ilme; Boutet, Sébastien; Groenhof, Gerrit; Chapman, Henry N.; Neutze, Richard

    2014-01-01

    A ‘protein quake’ describes the hypothesis that proteins rapidly dissipate energy through quake like structural motions. Here we measure ultrafast structural changes in the Blastochloris viridis photosynthetic reaction center following multi-photon excitation using time-resolved wide angle X-ray scattering at an X-ray free electron laser. A global conformational change arises within picoseconds, which precedes the propagation of heat through the protein. This motion is damped within a hundred picoseconds. PMID:25108686

  8. Effects of misaligned electron beam on inverse free electron laser acceleration

    NASA Astrophysics Data System (ADS)

    Khullar, Roma; Sharma, Geetanjali; Mishra, G.

    2015-02-01

    In this paper, we discuss the effects of misaligned electron beam on an inverse free electron laser with both an electromagnetic wave wiggler and magnetostatic wiggler acceleration scheme. It is shown analytically that electromagnetic wiggler IFEL energy gain distance is substantially smaller when compared to the standard IFEL i.e. with a magnetostatic wiggler. The analysis further explains a better tolerance of the electromagnetic wiggler IFEL with respect to the misaligned electron beam in comparison to a magnetostatic wiggler IFEL scheme.

  9. High-quality electron beams from a helical inverse free-electron laser accelerator.

    PubMed

    Duris, J; Musumeci, P; Babzien, M; Fedurin, M; Kusche, K; Li, R K; Moody, J; Pogorelsky, I; Polyanskiy, M; Rosenzweig, J B; Sakai, Y; Swinson, C; Threlkeld, E; Williams, O; Yakimenko, V

    2014-09-15

    Compact, table-top sized accelerators are key to improving access to high-quality beams for use in industry, medicine and academic research. Among laser-based accelerating schemes, the inverse free-electron laser (IFEL) enjoys unique advantages. By using an undulator magnetic field in combination with a laser, GeV m(-1) gradients may be sustained over metre-scale distances using laser intensities several orders of magnitude less than those used in laser wake-field accelerators. Here we show for the first time the capture and high-gradient acceleration of monoenergetic electron beams from a helical IFEL. Using a modest intensity (~10(13) W cm(-2)) laser pulse and strongly tapered 0.5 m long undulator, we demonstrate >100 MV m(-1) accelerating gradient, >50 MeV energy gain and excellent output beam quality. Our results pave the way towards compact, tunable GeV IFEL accelerators for applications such as driving soft X-ray free-electron lasers and producing γ-rays by inverse Compton scattering.

  10. High-quality electron beams from a helical inverse free-electron laser accelerator

    NASA Astrophysics Data System (ADS)

    Duris, J.; Musumeci, P.; Babzien, M.; Fedurin, M.; Kusche, K.; Li, R. K.; Moody, J.; Pogorelsky, I.; Polyanskiy, M.; Rosenzweig, J. B.; Sakai, Y.; Swinson, C.; Threlkeld, E.; Williams, O.; Yakimenko, V.

    2014-09-01

    Compact, table-top sized accelerators are key to improving access to high-quality beams for use in industry, medicine and academic research. Among laser-based accelerating schemes, the inverse free-electron laser (IFEL) enjoys unique advantages. By using an undulator magnetic field in combination with a laser, GeV m-1 gradients may be sustained over metre-scale distances using laser intensities several orders of magnitude less than those used in laser wake-field accelerators. Here we show for the first time the capture and high-gradient acceleration of monoenergetic electron beams from a helical IFEL. Using a modest intensity (~1013 W cm-2) laser pulse and strongly tapered 0.5 m long undulator, we demonstrate >100 MV m-1 accelerating gradient, >50 MeV energy gain and excellent output beam quality. Our results pave the way towards compact, tunable GeV IFEL accelerators for applications such as driving soft X-ray free-electron lasers and producing γ-rays by inverse Compton scattering.

  11. Two nonlinear models of the free-electron laser. Master's thesis

    SciTech Connect

    Kiel, D.H.

    1990-11-01

    The dynamics of the Free Electron Laser are governed by Maxwell's equations which causes many highly nonlinear regimes to exist in Free Electron Laser Physics. This thesis will examine two such areas and develop simple models to describe the highly dynamic and rich behavior two of these regimes. In the strong-field, high current regime, the Free Electron Laser driving current can be modeled by a single macroparticle representing the trapped electrons. When the trapped electrons act collectively as a macroparticle, solutions which include synchrotron oscillations can be found for the self-consistent pendulum and wave equations. In an FEL oscillator with low single-pass gain, the evolution of the optical wave can lead to sideband development. This phenomenon is studied by applying Maxwell's equations to an oscillator with two optical modes and deriving a two-mode wave and pendulum equation. The two-mode wave and pendulum equations are implemented numerically on computers so that the onset of the sideband can be explored.

  12. Modeling Of Induction-Linac Based Free-Electron Laser Amplifiers

    NASA Astrophysics Data System (ADS)

    Jong, Raynard A.; Fawley, William M.; Scharlemann, Ernst T.

    1989-05-01

    We describe the modeling of an induction-linac based free-electron laser (IFEL) amplifier for producing multi-megawatt levels of microwave power. We have used the Lawrence Livermore National Laboratory (LLNL) free-electron laser simulation code, FRED, and the simulation code for sideband calculations, GINGER for this study. For IFEL amplifiers in the frequency range of interest (200 to 600 GHz), we have devised a wiggler design strategy which incorporates a tapering algorithm that is suitable for free-electron laser (FEL) systems with moderate space-charge effects and that minimizes spontaneous noise growth at frequencies below the fundamental, while enhancing the growth of the signal at the fundamental. In addition, engineering design considerations of the waveguide wall loading and electron beam fill factor in the waveguide set limits on the waveguide dimensions, the wiggler magnet gap spacing, the wiggler period, and the minimum magnetic field strength in the tapered region of the wiggler. As an example, we shall describe an FEL amplifier designed to produce an average power of about 10 MW at a frequency of 280 GHz to be used for electron cyclotron resonance heating of tokamak fusion devices.

  13. Modeling of induction-linac based free-electron laser amplifiers

    NASA Astrophysics Data System (ADS)

    Jong, R. A.; Fawley, W. M.; Scharlemann, E. T.

    1988-12-01

    We describe the modeling of an induction-linac based free-electron laser (IFEL) amplifier for producing multimegawatt levels of microwave power. We have used the Lawrence Livermore National Laboratory (LLNL) free-electron laser simulation code, FRED, and the simulation code for sideband calculations, GINGER for this study. For IFEL amplifiers in the frequency range of interest (200 to 600 GHz), we have devised a wiggler design strategy which incorporates a tapering algorithm that is suitable for Free-Electron Laser (FEL) systems with moderate space-charge effects and that minimizes spontaneous noise growth at frequencies below the fundamental, while enhancing the growth of the signal at the fundamental. In addition, engineering design considerations of the waveguide wall loading and electron beam fill factor in the waveguide set limits on the waveguide dimensions, the wiggler magnet gap spacing, the wiggler period, and the minimum magnetic field strength in the tapered region of the wiggler. As an example, we shall describe an FEL amplifier designed to produce an average power of about 10 MW at a frequency of 280 GHz to be used for electron cyclotron resonance heating of tokamak fusion devices.

  14. Dispersion and attenuation in a Smith-Purcell free electron laser

    NASA Astrophysics Data System (ADS)

    Andrews, H. L.; Boulware, C. H.; Brau, C. A.; Jarvis, J. D.

    2005-05-01

    It has previously been shown that the electron beam in a Smith-Purcell free-electron laser interacts with a synchronous evanescent wave. At high electron energy, the group velocity of this wave is positive and the device operates on a convective instability, in the manner of a traveling-wave tube. For operation as an oscillator, the gain must exceed the losses in the external feedback system. At low electron energy, the group velocity of the synchronous evanescent wave is negative and the device operates on an absolute instability, like a backward-wave oscillator, and no external feedback is required. For oscillation to occur, the current must exceed the so-called start current. At an intermediate energy, called the Bragg condition, the group velocity vg of the evanescent wave vanishes and both the gain and the attenuation due to resistive losses in the grating diverge. It is shown that near the Bragg condition the gain depends on v-1/3g, while the attenuation depends on v-1g. Since the attenuation increases faster than the gain near the Bragg condition, the Smith-Purcell free-electron laser cannot operate at the point of maximum gain. The effects of resistive losses become increasingly important as Smith-Purcell free-electron lasers move to shorter wavelengths.

  15. Direct and secondary nuclear excitation with x-ray free-electron lasers

    SciTech Connect

    Gunst, Jonas; Wu, Yuanbin Kumar, Naveen; Keitel, Christoph H.; Pálffy, Adriana

    2015-11-15

    The direct and secondary nuclear excitation produced by an x-ray free electron laser when interacting with a solid-state nuclear target is investigated theoretically. When driven at the resonance energy, the x-ray free electron laser can produce direct photoexcitation. However, the dominant process in that interaction is the photoelectric effect producing a cold and very dense plasma in which also secondary processes such as nuclear excitation by electron capture may occur. We develop a realistic theoretical model to quantify the temporal dynamics of the plasma and the magnitude of the secondary excitation therein. Numerical results show that depending on the nuclear transition energy and the temperature and charge states reached in the plasma, secondary nuclear excitation by electron capture may dominate the direct photoexcitation by several orders of magnitude, as it is the case for the 4.8 keV transition from the isomeric state of {sup 93}Mo, or it can be negligible, as it is the case for the 14.4 keV Mössbauer transition in {sup 57}Fe. These findings are most relevant for future nuclear quantum optics experiments at x-ray free electron laser facilities.

  16. An infrared free-electron laser for the Chemical Dynamics Research Laboratory. Design report

    SciTech Connect

    Vaughan, D.

    1992-04-01

    This document describes a free-electron laser (FEL) proposed as part of the Chemical Dynamics Research Laboratory (CDRL), a user facility that also incorporates several advanced lasers of conventional design and two beamlines for the ALS. The FEL itself addresses the needs of the chemical sciences community for a high-brightness, tunable source covering a broad region of the infrared spectrum -- from 3 to 50 {mu}m. All of these sources, together with a variety of sophisticated experimental stations, will be housed in a new building to be located adjacent to the ALS. The radiation sources can be synchronized to permit powerful two-color, pump-probe experiments that will further our fundamental understanding of chemical dynamics at the molecular level, especially those aspects relevant to practical issues in combustion chemistry. The technical approach adopted in this design makes use of superconducting radiofrequency (SCRF) accelerating structures. The primary motivation for adopting this approach was to meet the user requirement for wavelength stability equal to one part in 10{sup 4}. Previous studies concluded that a wavelength stability of only one part in 10{sup 3} could be achieved with currently available room-temperature technology. In addition, the superconducting design operates in a continuous-wave (cw) mode and hence offers considerably higher average optical output power. It also allows for various pulse-gating configurations that will permit simultaneous multiuser operations. A summary of the comparative performance attainable with room-temperature and superconducting designs is given. The FEL described in this report provides a continuous train of 30-ps micropulses, with 100{mu}J of optical energy per micropulse, at a repetition rate of 6.1 MHz. The device can also deliver pulses at a cw repetition rate of 12.2 MHz, with a peak power of 50 {mu}J per micropulse. 70 ref.

  17. An infrared free-electron laser for the Chemical Dynamics Research Laboratory

    SciTech Connect

    Vaughan, D.

    1992-04-01

    This document describes a free-electron laser (FEL) proposed as part of the Chemical Dynamics Research Laboratory (CDRL), a user facility that also incorporates several advanced lasers of conventional design and two beamlines for the ALS. The FEL itself addresses the needs of the chemical sciences community for a high-brightness, tunable source covering a broad region of the infrared spectrum -- from 3 to 50 {mu}m. All of these sources, together with a variety of sophisticated experimental stations, will be housed in a new building to be located adjacent to the ALS. The radiation sources can be synchronized to permit powerful two-color, pump-probe experiments that will further our fundamental understanding of chemical dynamics at the molecular level, especially those aspects relevant to practical issues in combustion chemistry. The technical approach adopted in this design makes use of superconducting radiofrequency (SCRF) accelerating structures. The primary motivation for adopting this approach was to meet the user requirement for wavelength stability equal to one part in 10{sup 4}. Previous studies concluded that a wavelength stability of only one part in 10{sup 3} could be achieved with currently available room-temperature technology. In addition, the superconducting design operates in a continuous-wave (cw) mode and hence offers considerably higher average optical output power. It also allows for various pulse-gating configurations that will permit simultaneous multiuser operations. A summary of the comparative performance attainable with room-temperature and superconducting designs is given. The FEL described in this report provides a continuous train of 30-ps micropulses, with 100{mu}J of optical energy per micropulse, at a repetition rate of 6.1 MHz. The device can also deliver pulses at a cw repetition rate of 12.2 MHz, with a peak power of 50 {mu}J per micropulse. 70 ref.

  18. Application of Strong Field Physics Techniques to X-Ray Free Electron Laser Science

    NASA Astrophysics Data System (ADS)

    Roedig, Christoph Antony

    With the commissioning of the Linac Coherent Light Source (LCLS), the first x-ray free electron laser (XFEL) was realized at the Stanford Linear Accelerator Center. This novel device brings an unprecedented parameter set to a diverse community of scientists. The short wavelengths and short pulse durations enable an entire new class of time resolved structural analysis. The imaging capabilities enabled by the machine will lead to many breakthroughs in the fields of biophysics and nano technology. With the new capabilities of the LCLS come many challenges. The understanding required to effectively utilize the XFEL on complex molecular or biological systems goes back to the basic atomic physics of the interaction of light and matter. The parameter set of this machine is as unprecedented as it will be untested. To make informed measurements with the LCLS beam, a set of novel diagnostic techniques will be required. This report outlines major contributions made to the early experimental atomic physics and diagnostic efforts at LCLS. Building on a rich history of techniques used for ultra short optical lasers and atomic physics experimentation, a diagnostic instrument and experimental techniques are developed to make spectral, energy and temporal measurements of the LCLS pulses possible. Expanding on earlier studies of ionization performed on optical lasers and synchrotron sources, new ionization mechanisms such as multiphoton ionization in the x-ray regime are observed. Leveraging the unique combination of hard x-ray photon energy, extremely short pulse duration and high pulse energy, a technique for the time resolved study of ultrafast inner shell electronic relaxation processes is developed and studied for feasibility. The common theme to the efforts described here is the advancement of proven techniques and interesting atomic physics phenomena to the next generation of ultra short pulsed x-ray laser systems. The atomic physics explored here lay the groundwork for the

  19. A theory for optical wavelength control in short pulse free electron laser oscillators

    NASA Astrophysics Data System (ADS)

    Wilkenson, Wade F.

    1993-06-01

    The future safety of the U.S. Navy warship depends on the development of a directed energy self-defense system to keep pace with the ever-improving technology of anti-ship missiles. Two candidates are reviewed. The free electron laser (FEL) has the most advantages, but a chemical laser proposed by TRW is ready for installation on existing ships. Initial testing of issues related to directed energy use at sea can be conducted with the chemical laser. When the technology of the FEL matures, it can replace the chemical laser to provide the best possible defense in the shortest period of time. Continuous tunability is a key advantage of the FEL over the conventional laser. But since the output wavelength is dependent on electron energy, it is subject to random fluctuations originating from the beam source. At the Stanford University Superconducting (SCA) Free Electron Laser (FEL) Facility, the effects are minimized through negative feedback by changing the input electron energy proportional to the observed wavelength drift. The process is simulated by modifying a short pulse FEL numerical program to allow the resonant wavelength to vary over many passes. The physical effects behind optical wavelength control are explained. A theory for the preferential nature of the FEL to follow the resonant wavelength from longer to shorter wavelengths is presented. Finally, the response of the FEL to a rapidly changing resonant wavelength is displayed as a transfer function for the system.

  20. Alternative lattice options for energy recovery in high-average-power high-efficiency free-electron lasers

    SciTech Connect

    Piot, P.; /Northern Illinois U. /NICADD, DeKalb /Fermilab

    2009-03-01

    High-average-power free-electron lasers often rely on energy-recovering linacs. In a high-efficiency free electron laser, the main limitation to high average power stems from the fractional energy spread induced by the free-electron laser process. Managing beams with large fractional energy spread while simultaneously avoiding beam losses is extremely challenging and relies on intricate longitudinal phase space manipulations. In this paper we discuss a possible alternative technique that makes use of an emittance exchange between one of the transverse and the longitudinal phase spaces.

  1. Characterization of a high-gain harmonic-generation free-electron laser at saturation.

    PubMed

    Doyuran, A; Babzien, M; Shaftan, T; Yu, L H; DiMauro, L F; Ben-Zvi, I; Biedron, S G; Graves, W; Johnson, E; Krinsky, S; Malone, R; Pogorelsky, I; Skaritka, J; Rakowsky, G; Wang, X J; Woodle, M; Yakimenko, V; Jagger, J; Sajaev, V; Vasserman, I

    2001-06-25

    We report on an experimental investigation characterizing the output of a high-gain harmonic-generation (HGHG) free-electron laser (FEL) at saturation. A seed CO2 laser at a wavelength of 10.6 microm was used to generate amplified FEL output at 5.3 microm. Measurement of the frequency spectrum, pulse duration, and correlation length of the 5.3 microm output verified that the light is longitudinally coherent. Investigation of the electron energy distribution and output harmonic energies provides evidence for saturated HGHG FEL operation.

  2. Endstation for ultrafast magnetic scattering experiments at the free-electron laser in Hamburg

    SciTech Connect

    Mueller, L.; Gutt, C.; Streit-Nierobisch, S.; Walther, M.; Gruebel, G.; Schaffert, S.; Pfau, B.; Flewett, S.; Geilhufe, J.; Eisebitt, S.; Buettner, F.; Guenther, C. M.; Kobs, A.; Hille, M.; Stickler, D.; Froemter, R.; Oepen, H. P.; Luening, J.

    2013-01-15

    An endstation for pump-probe small-angle X-ray scattering (SAXS) experiments at the free-electron laser in Hamburg (FLASH) is presented. The endstation houses a solid-state absorber, optical incoupling for pump-probe experiments, time zero measurement, sample chamber, and detection unit. It can be used at all FLASH beamlines in the whole photon energy range offered by FLASH. The capabilities of the setup are demonstrated by showing the results of resonant magnetic SAXS measurements on cobalt-platinum multilayer samples grown on freestanding Si{sub 3}N{sub 4} membranes and pump-laser-induced grid structures in multilayer samples.

  3. Efficiency and Spectrum Enhancement in a Tapered Free-Electron Laser Amplifier

    SciTech Connect

    Wang, X. J.; Harder, D.; Murphy, J. B.; Qian, H.; Shen, Y.; Yang, X.; Freund, H. P.; Miner, W. H. Jr.

    2009-10-09

    We report the first experimental characterization of efficiency and spectrum enhancement in a laser-seeded free-electron laser using a tapered undulator. Output and spectra in the fundamental and third harmonic were measured versus distance for uniform and tapered undulators. With a 4% field taper over 3 m, a 300% (50%) increase in the fundamental (third harmonic) output was observed. A significant improvement in the spectra with the elimination of sidebands was observed using a tapered undulator. The experiment is in good agreement with predictions using the MEDUSA simulation code.

  4. Endstation for ultrafast magnetic scattering experiments at the free-electron laser in Hamburg

    NASA Astrophysics Data System (ADS)

    Müller, L.; Gutt, C.; Streit-Nierobisch, S.; Walther, M.; Schaffert, S.; Pfau, B.; Geilhufe, J.; Büttner, F.; Flewett, S.; Günther, C. M.; Eisebitt, S.; Kobs, A.; Hille, M.; Stickler, D.; Frömter, R.; Oepen, H. P.; Lüning, J.; Grübel, G.

    2013-01-01

    An endstation for pump-probe small-angle X-ray scattering (SAXS) experiments at the free-electron laser in Hamburg (FLASH) is presented. The endstation houses a solid-state absorber, optical incoupling for pump-probe experiments, time zero measurement, sample chamber, and detection unit. It can be used at all FLASH beamlines in the whole photon energy range offered by FLASH. The capabilities of the setup are demonstrated by showing the results of resonant magnetic SAXS measurements on cobalt-platinum multilayer samples grown on freestanding Si_3N_4 membranes and pump-laser-induced grid structures in multilayer samples.

  5. Prospects for using X-ray free-electron lasers to investigate shock-compressed matter

    SciTech Connect

    Nagler, Bob; Higginbotham, Andrew; Kimminau, Giles; Murphy, William; Whitcher, Thomas; Wark, Justin; Hawreliak, James; Kalantar, Dan; Lee, Richard; Lorenzana, Hector; Remington, Bruce; Larsson, Jorgen; Park, Nigel; Sokolowski-Tinten, Klaus

    2007-12-12

    Within the next few years hard X-ray Free Electron Lasers will come on line. Such systems will have spectral brightnesses ten orders of magnitude greater than any extant synchrotron, with pulse lengths as short as a few femtoseconds. It is anticipated that large-scale optical lasers capable of shock-compressing matter to multi-megabar pressures will be sited alongside the X-ray source. We discuss how such systems can further our knowledge of shocked and isochorically heated matter, in particular investigating the potential to perform polycrystalline diffraction and the creation of warm dense matter.

  6. Studies of fullerene absorption and production using an infrared free-electron laser

    SciTech Connect

    Affatigato, M.; Haglund, R.F.; Ying, Z.C.; Compton, R.N.

    1995-12-31

    Tunable photon sources such as free-electron lasers are potentially valuable tools in spectroscopic studies of fullerenes, a new class of carbon materials with unique cage structures. We have used the infrared free-electron-laser facility at Vanderbilt University to study the infrared absorption of gas-phase fullerene molecules and also to investigate the effects of an infrared laser in the synthesis and crystallization of fullerene materials. In one experiment, fullerene vapor was created in a heat pipe through which the FEL beam was passed; the transmission of the FEL beam relative to a reference detector was measured as a function of wavelength. A large (>10%) absorption of the IR laser was observed when it passed through C{sub 60} vapor at {approximately}800{degrees}C. Due to the broad spectral width of the FEL as well as spectral congestion, no spectral peaks were seen when the laser wavelength was tuned across a T{sub 1u}C{sub 60} IR mode near 7.0 {mu}. However, it is expected that the vibrational features can be resolved experimentally by passing the transmitted beam through a monochromator. In a separate experiment, the FEL beam was focused onto a surface of graphite or graphite/metal mixture target. Various fullerene molecules, including endohedral types, were produced when the soot was recovered from the ablation chamber. The yield of the products was measured to be {approximately}0.4 g/J of the incident laser energy. However, both the yield and the product distribution are virtually, the same as those in experiments using a nanosecond Nd:YAG laser. This suggests that the laser wavelength is not a crucial parameter in making fullerenes by laser ablation. Even when the laser is at resonance with one of the vibrational modes of C{sub 60}, the fullerene production is neither substantially enhanced nor suppressed.

  7. R&D for a Soft X-Ray Free Electron Laser Facility

    SciTech Connect

    Corlett, John; Attwood, David; Byrd, John; Denes, Peter; Falcone, Roger; Heimann, Phil; Leemans, Wim; Padmore, Howard; Prestemon, Soren; Sannibale, Fernando; Schlueter, Ross; Schroeder, Carl; Staples, John; Venturini, Marco; Warwick, Tony; Wells, Russell; Wilcox, Russell; Zholent, Alexander; Adolphsen, Chris; Arthur, John; Bergmann, Uwe; Cai, Yunhai; Colby, Eric; Dowell, David; Emma, Paul; Fox, John; Frisch, Josef; Galayda, John; Hettel, Robert; Huang, Zhirong; Phinney, Nan; Rabedeau, Tom; Raubenheimer, Tor; Reis, David; Schmerge, John; Stohr, Joachim; Stupakov, Gennady; White, Bill; Xiang, Dao

    2009-06-08

    Several recent reports have identified the scientific requirements for a future soft x-ray light source, and a high-repetition-rate free-electron laser (FEL) facility that is responsive to these requirements is now on the horizon. R&D in some critical areas is needed, however, to demonstrate technical performance, thus reducing technical risks and construction costs. Such a facility most likely will be based on a CW superconducting linear accelerator with beam supplied by a high-brightness, high-repetition-rate photocathode electron gun operating in CW mode, and on an array of FELs to which the accelerated beam is distributed, each operating at high repetition rate and with even pulse spacing. Dependent on experimental requirements, the individual FELs can be configured for either self-amplified spontaneous emission (SASE), seeded, or oscillator mode of operation, including the use of high-gain harmonic generation (HGHG), echo-enhanced harmonic generation (EEHG), harmonic cascade, or other configurations. In this White Paper we identify the overall accelerator R&D needs, and highlight the most important pre-construction R&D tasks required to value-engineer the design configuration and deliverables for such a facility. In Section 1.4 we identify the comprehensive R&D ultimately needed. We identify below the highest-priority requirements for understanding machine performance and reduce risk and costs at this pre-conceptual design stage. Details of implementing the required tasks will be the subject of future evaluation. Our highest-priority R&D program is the injector, which must be capable of delivering a beam with bunches up to a nanocoulomb at MHz repetition rate and with normalized emittance {le} 1 mm {center_dot} mrad. This will require integrated accelerating structure, cathode, and laser systems development. Cathode materials will impact the choice of laser technology in wavelength and energy per pulse, as well as vacuum requirements in the accelerating

  8. Quantum effects with an x-ray free-electron laser.

    PubMed

    Roberts, C D; Schmidt, S M; Vinnik, D V

    2002-10-07

    A quantum kinetic equation coupled with Maxwell's equation is used to estimate the laser power required at an x-ray free-electron laser (XFEL) facility to expose intrinsically quantum effects in the process of QED vacuum decay via spontaneous pair production. A 9 -TW-peak XFEL laser with photon energy of 8.3 keV could be sufficient to initiate particle accumulation and the consequent formation of a plasma of spontaneously produced pairs. The evolution of the particle number in the plasma will exhibit non-Markovian aspects of the strong-field pair production process, and the plasma's internal currents will generate an electric field whose interference with that of the laser leads to plasma oscillations.

  9. High-gain X-ray free electron laser by beat-wave terahertz undulator

    SciTech Connect

    Chang, Chao; Hei, DongWei; Pellegrin, Claudio; Tantawi, Sami

    2013-12-15

    The THz undulator has a higher gain to realize a much brighter X-ray at saturation, compared with the optical undulator under the same undulator strength and beam quality. In order to fill the high-power THz gap and realize the THz undulator, two superimposed laser pulses at normal incidence to the electron-beam moving direction form an equivalent high-field THz undulator by the frequency difference to realize the high-gain X-ray Free electron laser. The pulse front tilt of lateral fed lasers is used to realize the electron-laser synchronic interaction. By PIC simulation, a higher gain and a larger X-ray radiation power by the beat wave THz undulator could be realized, compared with the optical undulator for the same electron beam parameters.

  10. PROCEEDING OF THE SEEDED X-RAY FREE ELECTRON LASER WORKSHOP.

    SciTech Connect

    WANG,X.J.; MURPHY,J.B.; YU,L.H.; FAATZ,B.; HUANG,Z.; REICHE,S.; ZOLOTOREV,M.

    2002-12-13

    The underlying theory of a high gain free electron laser (FEL) has existed for two decades [1-2], but it is only in the last few years that these novel radiation sources have been realized experimentally. Several high gain FELs have successfully reached saturation in the infrared, visible and the VUV portion of the spectrum: the High Gain Harmonic Generation (HGHG) free electron lasers [3] at BNL and the Self Amplified Spontaneous Emission (SASE) FELs at LEUTL, VISA and TTF [4-6]. The outstanding challenges for future FELs are to extend high gain FELs to the X-ray regime, improve the longitudinal coherence of the radiation using seeded FEL schemes and generate ultrashort pulses (<100 fs). The National Synchrotron Light Source (NSLS) of the Brookhaven National Laboratory (BNL) sponsored a Seeded X-ray Free Electron Laser Workshop on December 13-14, 2002 to explore these challenging issues. Representatives from BNL, DESY, LBNL, SLAC and UCLA made presentations on the novel schemes under consideration at their laboratories. Workshop participants had a lively discussion on the feasibility, performance and R&D issues associated with the seeded XFEL schemes. An improvement of the electron beam quality will certainly be necessary to drive the XFEL. Self-seeding SASE, cascaded HGHG, and SASE pulse compression FELs show the most promise for producing short pulse X-rays. Of these, only the self-seeded and HGHG schemes generate longitudinally coherent radiation. While the pulse length in the self-seeded scheme is determined by the electron bunch length ({approx}100 fs), the pulse length in the HGHG scheme is determined by the short pulse seed laser, and so can be much shorter ({approx} 20 fs).

  11. Determination of x-ray free electron laser power using a room-temperature calorimeter

    NASA Astrophysics Data System (ADS)

    Tanaka, T.; Kato, M.; Saito, N.; Tono, K.; Yabashi, M.; Ishikawa, T.

    2016-02-01

    A room-temperature calorimeter was developed for the absolute laser power measurement of x-ray free electron lasers (XFELs) at the SPring-8 Angstrom Compact free electron LAser facility in Japan. In the photon energy range from 4.5 keV to 15 keV, this calorimeter was demonstrated to accurately measure laser powers of XFEL up to 6.9 mW. In addition, an online beam monitor, based on the detection of backscattered x-rays from a thin diamond film, was calibrated with the room-temperature calorimeter. The calibration results were compared with those obtained previously with a cryogenic radiometer (the primary standard detector for synchrotron radiations in Japan). The calibration results obtained with the two detectors agreed well within 1.2%, which is well below their combined relative standard uncertainty. Moreover, the spectral responsivity of the beam monitor was found to show a strong photon energy dependence owing to Debye-Scherrer diffraction patterns from the thin-film.

  12. Very High Energy Gain at the Neptune Inverse Free Electron Laser Experiment

    SciTech Connect

    Musumeci, P.; Boucher, S.; Doyuran, A.; England, R. J.; Pellegrini, C.; Rosenzweig, J. B.; Travish, G.; Yoder, R.; Tochitsky, S.Ya.; Joshi, C.; Ralph, J.; Sung, C.; Tolmachev, S.; Varfolomeev, A.; Varfolomeev, A. Jr.; Yarovoi, T.

    2004-12-07

    We report the observation of energy gain in excess of 20 MeV at the Inverse Free Electron Laser Accelerator experiment at the Neptune Laboratory at UCLA. A 14.5 MeV electron beam is injected in an undulator strongly tapered in period and field amplitude. The IFEL driver is a CO2 10.6 {mu}m laser with power larger than 400 GW. The Rayleigh range of the laser, {approx} 1.8 cm, is much shorter than the undulator length so that the interaction is diffraction dominated. A few per cent of the injected particles are trapped in a stable accelerating bucket. Electrons with energies up to 35 MeV are measured by a magnetic spectrometer. Three-dimensional simulations, in good agreement with the measured electron energy spectrum, indicate that most of the acceleration occurs in the first 25 cm of the undulator, corresponding to an energy gradient larger than 70 MeV/m. The measured energy spectrum also indicates that higher harmonic Inverse Free Electron Laser interaction takes place in the second section of the undulator.

  13. Very High Energy Gain at the Neptune Inverse Free Electron Laser Experiment

    NASA Astrophysics Data System (ADS)

    Musumeci, P.; Tochitsky, S. Ya.; Boucher, S.; Doyuran, A.; England, R. J.; Joshi, C.; Pellegrini, C.; Ralph, J.; Rosenzweig, J. B.; Sung, C.; Tolmachev, S.; Travish, G.; Varfolomeev, A.; Varfolomeev, A.; Yarovoi, T.; Yoder, R.

    2004-12-01

    We report the observation of energy gain in excess of 20 MeV at the Inverse Free Electron Laser Accelerator experiment at the Neptune Laboratory at UCLA. A 14.5 MeV electron beam is injected in an undulator strongly tapered in period and field amplitude. The IFEL driver is a CO2 10.6 μm laser with power larger than 400 GW. The Rayleigh range of the laser, ~ 1.8 cm, is much shorter than the undulator length so that the interaction is diffraction dominated. A few per cent of the injected particles are trapped in a stable accelerating bucket. Electrons with energies up to 35 MeV are measured by a magnetic spectrometer. Three-dimensional simulations, in good agreement with the measured electron energy spectrum, indicate that most of the acceleration occurs in the first 25 cm of the undulator, corresponding to an energy gradient larger than 70 MeV/m. The measured energy spectrum also indicates that higher harmonic Inverse Free Electron Laser interaction takes place in the second section of the undulator.

  14. An application of laser-plasma acceleration: towards a free-electron laser amplification

    NASA Astrophysics Data System (ADS)

    Couprie, M. E.; Labat, M.; Evain, C.; Marteau, F.; Briquez, F.; Khojoyan, M.; Benabderrahmane, C.; Chapuis, L.; Hubert, N.; Bourassin-Bouchet, C.; El Ajjouri, M.; Bouvet, F.; Dietrich, Y.; Valléau, M.; Sharma, G.; Yang, W.; Marcouillé, O.; Vétéran, J.; Berteaud, P.; El Ajjouri, T.; Cassinari, L.; Thaury, C.; Lambert, G.; Andriyash, I.; Malka, V.; Davoine, X.; Tordeux, M. A.; Miron, C.; Zerbib, D.; Tavakoli, K.; Marlats, J. L.; Tilmont, M.; Rommeluère, P.; Duval, J. P.; N'Guyen, M. H.; Rouqier, A.; Vanderbergue, M.; Herbeaux, C.; Sebdouai, M.; Lestrade, A.; Leclercq, N.; Dennetière, D.; Thomasset, M.; Polack, F.; Bielawski, S.; Szwaj, C.; Loulergue, A.

    2016-03-01

    The laser-plasma accelerator (LPA) presently provides electron beams with a typical current of a few kA, a bunch length of a few fs, energy in the few hundred MeV to several GeV range, a divergence of typically 1 mrad, an energy spread of the order of 1%, and a normalized emittance of the order of π.mm.mrad. One of the first applications could be to use these beams for the production of radiation: undulator emission has been observed but the rather large energy spread (1%) and divergence (1 mrad) prevent straightforward free-electron laser (FEL) amplification. An adequate beam manipulation through the transport to the undulator is then required. The key concept proposed here relies on an innovative electron beam longitudinal and transverse manipulation in the transport towards an undulator: a ‘demixing’ chicane sorts the electrons according to their energy and reduces the spread from 1% to one slice of a few ‰ and the effective transverse size is maintained constant along the undulator (supermatching) by a proper synchronization of the electron beam focusing with the progress of the optical wave. A test experiment for the demonstration of FEL amplification with an LPA is under preparation. Electron beam transport follows different steps with strong focusing with permanent magnet quadrupoles of variable strength, a demixing chicane with conventional dipoles, and a second set of quadrupoles for further focusing in the undulator. The FEL simulations and the progress of the preparation of the experiment are presented.

  15. First observation of self-amplified spontaneous emission in a free-electron laser at 109 nm wavelength

    PubMed

    Saldin; Sandner; Sanok; Schlarb; Schmidt; Schmuser; Schneider; Schneidmiller; Schreiber; Schreiber; Schutt; Sekutowicz; Serafini; Sertore; Setzer; Simrock; Sonntag; Sparr; Stephan; Sytchev; Tazzari; Tazzioli; Tigner; Timm; Tonutti; Trakhtenberg

    2000-10-30

    We present the first observation of self-amplified spontaneous emission (SASE) in a free-electron laser (FEL) in the vacuum ultraviolet regime at 109 nm wavelength (11 eV). The observed free-electron laser gain (approximately 3000) and the radiation characteristics, such as dependency on bunch charge, angular distribution, spectral width, and intensity fluctuations, are all consistent with the present models for SASE FELs.

  16. Free electron laser-driven ultrafast rearrangement of the electronic structure in Ti

    PubMed Central

    Principi, E.; Giangrisostomi, E.; Cucini, R.; Bencivenga, F.; Battistoni, A.; Gessini, A.; Mincigrucci, R.; Saito, M.; Di Fonzo, S.; D'Amico, F.; Di Cicco, A.; Gunnella, R.; Filipponi, A.; Giglia, A.; Nannarone, S.; Masciovecchio, C.

    2015-01-01

    High-energy density extreme ultraviolet radiation delivered by the FERMI seeded free-electron laser has been used to create an exotic nonequilibrium state of matter in a titanium sample characterized by a highly excited electron subsystem at temperatures in excess of 10 eV and a cold solid-density ion lattice. The obtained transient state has been investigated through ultrafast absorption spectroscopy across the Ti M2,3-edge revealing a drastic rearrangement of the sample electronic structure around the Fermi level occurring on a time scale of about 100 fs. PMID:26798835

  17. Radiation damage in protein serial femtosecond crystallography using an x-ray free-electron laser

    PubMed Central

    Lomb, Lukas; Barends, Thomas R. M.; Kassemeyer, Stephan; Aquila, Andrew; Epp, Sascha W.; Erk, Benjamin; Foucar, Lutz; Hartmann, Robert; Rudek, Benedikt; Rolles, Daniel; Rudenko, Artem; Shoeman, Robert L.; Andreasson, Jakob; Bajt, Sasa; Barthelmess, Miriam; Barty, Anton; Bogan, Michael J.; Bostedt, Christoph; Bozek, John D.; Caleman, Carl; Coffee, Ryan; Coppola, Nicola; DePonte, Daniel P.; Doak, R. Bruce; Ekeberg, Tomas; Fleckenstein, Holger; Fromme, Petra; Gebhardt, Maike; Graafsma, Heinz; Gumprecht, Lars; Hampton, Christina Y.; Hartmann, Andreas; Hauser, Günter; Hirsemann, Helmut; Holl, Peter; Holton, James M.; Hunter, Mark S.; Kabsch, Wolfgang; Kimmel, Nils; Kirian, Richard A.; Liang, Mengning; Maia, Filipe R. N. C.; Meinhart, Anton; Marchesini, Stefano; Martin, Andrew V.; Nass, Karol; Reich, Christian; Schulz, Joachim; Seibert, M. Marvin; Sierra, Raymond; Soltau, Heike; Spence, John C. H.; Steinbrener, Jan; Stellato, Francesco; Stern, Stephan; Timneanu, Nicusor; Wang, Xiaoyu; Weidenspointner, Georg; Weierstall, Uwe; White, Thomas A.; Wunderer, Cornelia; Chapman, Henry N.; Ullrich, Joachim; Strüder, Lothar; Schlichting, Ilme

    2013-01-01

    X-ray free-electron lasers deliver intense femtosecond pulses that promise to yield high resolution diffraction data of nanocrystals before the destruction of the sample by radiation damage. Diffraction intensities of lysozyme nanocrystals collected at the Linac Coherent Light Source using 2 keV photons were used for structure determination by molecular replacement and analyzed for radiation damage as a function of pulse length and fluence. Signatures of radiation damage are observed for pulses as short as 70 fs. Parametric scaling used in conventional crystallography does not account for the observed effects. PMID:24089594

  18. Evidence for microbunching "sidebands" in a saturated free-electron laser using coherent optical transition radiation.

    PubMed

    Lumpkin, A H; Dejus, R; Lewellen, J W; Berg, W; Biedron, S; Borland, M; Chae, Y C; Erdmann, M; Huang, Z; Kim, K-J; Li, Y; Milton, S V; Moog, E; Rule, D W; Sajaev, V; Yang, B X

    2002-06-10

    We report the first measurements of z-dependent coherent optical transition radiation (COTR) due to electron-beam microbunching at high gains ( >10(4)) including saturation of a self-amplified spontaneous emission free-electron laser (FEL). In these experiments the fundamental wavelength was near 530 nm, and the COTR spectra exhibit the transition from simple spectra to complex spectra ( 5% spectral width) after saturation. The COTR intensity growth and angular distribution data are reported as well as the evidence for transverse spectral dependencies and an "effective" core of the beam being involved in microbunching.

  19. Beam shaping to improve the free-electron laser performance at the Linac Coherent Light Source

    DOE PAGES

    Ding, Y.; Bane, K. L. F.; Colocho, W.; ...

    2016-10-27

    A new operating mode has been developed for the Linac Coherent Light Source (LCLS) in which we shape the longitudinal phase space of the electron beam. This mode of operation is realized using a horizontal collimator located in the middle of the first bunch compressor to truncate the head and tail of the beam. With this method, the electron beam longitudinal phase space and current profile are reshaped, and improvement in lasing performance can be realized. As a result, we present experimental studies at the LCLS of the beam shaping effects on the free-electron laser performance.

  20. Mixing and space-charge effects in free-electron lasers

    SciTech Connect

    Peter, E.; Endler, A.; Rizzato, F. B.; Serbeto, A.

    2013-12-15

    The present work revisits the subjects of mixing, saturation, and space-charge effects in free-electron lasers. Use is made of the compressibility factor, which proves to be a helpful tool in the related systems of charged beams confined by static magnetic fields. The compressibility allows to perform analytical estimates of the elapsed time until the onset of mixing, which in turn allows to estimate the saturated amplitude of the radiation field. In addition, the compressibility helps to pinpoint space-charge effects and the corresponding transition from Compton to Raman regimes.

  1. Inverse free electron laser beat-wave accelerator research. Annual progress report, [August 1992--September 1993

    SciTech Connect

    Marshall, T.C.; Bhattacharjee, A.

    1993-09-01

    A calculation on the stabilization of the sideband instability in the free electron laser (FEL) and inverse FEL (IFEL) was completed. The issue arises in connection with the use of a tapered (``variable-parameter``) undulator of extended length, such as might be used in an ``enhanced efficiency`` traveling-wave FEL or an IFEL accelerator. In addition, the FEL facility at Columbia was configured as a traveling wave amplifier for a 10-kW signal from a 24-GHz magnetron. The space charge field in the bunches of the FEL was measured. Completed work has been published.

  2. Competition between coherent emission and broadband spontaneous emission in the quantum free electron laser

    SciTech Connect

    Robb, G. R. M.; Bonifacio, R.

    2013-03-15

    We extend previous analyses of spontaneous emission in a quantum free electron laser (QFEL) and competition between spontaneous and coherent QFEL emission to include a broad distribution of photon frequencies and momenta appropriate for spontaneous undulator radiation. We show that although the predictions of monochromatic and broadband models predict different electron momentum distributions for the quantum regime due to spontaneous emission alone after many photon emissions, the inclusion of broadband spontaneous emission has a negligible effect on the competition between spontaneous and coherent emission in the QFEL. Numerical results from both models are well described by the same condition for the threshold/critical value of spontaneous emission rate.

  3. Free-Electron Laser as a Driver for a Resonant Cavity at 35 GHz

    NASA Astrophysics Data System (ADS)

    Lefevre, T.; Gardelle, J.; Rullier, J. L.; Vermare, C.; Donohue, J. T.; Meurdesoif, Y.; Lidia, S. M.

    2000-02-01

    An intense beam of relativistic electrons (800 A, 6.7 MeV) has been bunched at 35 GHz by a free-electron laser, in which output power levels exceeding 100 MW were obtained. The beam was then extracted and transported through a resonant cavity, which was excited by its passage. Microwave power levels of 10 MW were extracted from the cavity, in reasonable agreement with the simple formula which relates power to known properties of both the beam and the cavity.

  4. W-Band Free Electron Laser for High Gradient Structure Research

    NASA Astrophysics Data System (ADS)

    Lidia, S. M.; Whittum, D. H.; Donohue, J. T.

    1997-05-01

    We discuss the use of a free electron laser in support of material stress studies of W-band high-gradient accelerating structures. We propose the use of the linear induction accelerator LELIA (CEA/CESTA, France) to generate a 1-kiloamp, 80-ns FWHM electron pulse. We present a design for a helical FEL TE_11 amplifier that will generate high peak power (100's MW) at 93 GHz. We support our design with analytical estimates of gain, and with numerical simulations of power and phase development.

  5. Free-electron laser as a driver for a resonant cavity at 35 GHz

    PubMed

    Lefevre; Gardelle; Rullier; Vermare; Donohue; Meurdesoif; Lidia

    2000-02-07

    An intense beam of relativistic electrons (800 A, 6.7 MeV) has been bunched at 35 GHz by a free-electron laser, in which output power levels exceeding 100 MW were obtained. The beam was then extracted and transported through a resonant cavity, which was excited by its passage. Microwave power levels of 10 MW were extracted from the cavity, in reasonable agreement with the simple formula which relates power to known properties of both the beam and the cavity.

  6. Algorithm for loading shot noise microbunching in multidimensional, free-electron laser simulation codes

    NASA Astrophysics Data System (ADS)

    Fawley, William M.

    2002-07-01

    We discuss the underlying reasoning behind and the details of the numerical algorithm used in the GINGER free-electron laser simulation code to load the initial shot noise microbunching on the electron beam. In particular, we point out that there are some additional subtleties which must be followed for multidimensional codes which are not necessary for one-dimensional formulations. Moreover, requiring that the higher harmonics of the microbunching also be properly initialized with the correct statistics leads to additional complexities. We present some numerical results including the predicted incoherent, spontaneous emission as tests of the shot noise algorithm's correctness.

  7. Algorithm for loading shot noise microbunching in multi-dimensional, free-electron laser simulation codes

    SciTech Connect

    Fawley, William M.

    2002-03-25

    We discuss the underlying reasoning behind and the details of the numerical algorithm used in the GINGER free-electron laser(FEL) simulation code to load the initial shot noise microbunching on the electron beam. In particular, we point out that there are some additional subtleties which must be followed for multi-dimensional codes which are not necessary for one-dimensional formulations. Moreover, requiring that the higher harmonics of the microbunching also be properly initialized with the correct statistics leads to additional complexities. We present some numerical results including the predicted incoherent, spontaneous emission as tests of the shot noise algorithm's correctness.

  8. Ultrafast Coherent Diffraction Imaging with X-ray Free-Electron Lasers

    SciTech Connect

    Chapman, H N; Bajt, S; Barty, A; Benner, W; Bogan, M; Frank, M; Hau-Riege, S; London, R; Marchesini, S; Spiller, E; Szoke, A; Woods, B; Boutet, S; Hodgson, K; Hajdu, J; Bergh, M; Burmeister, F; Caleman, C; Huldt, G; Maia, F; Seibert, M M; der Spoel, D v

    2006-08-22

    The ultrafast pulses from X-ray free-electron lasers will enable imaging of non-periodic objects at near-atomic resolution [1, Neutze]. These objects could include single molecules, protein complexes, or virus particles. The specimen would be completely destroyed by the pulse in a Coulomb explosion, but that destruction will only happen after the pulse. The scattering from the sample will give structural information about the undamaged object. There are many technical challenges that must be addressed before carrying out such experiments at an XFEL, which we are doing so with experiments at FLASH, the soft-X-ray FEL at DESY.

  9. Canalization of radiation by a ribbon relativistic electron beam in free electron lasers

    NASA Astrophysics Data System (ADS)

    Ginzburg, N. S.; Sergeev, A. S.

    1989-03-01

    Canalization (optical guiding) of radiation by a ribbon relativistic electron beam in a free electron laser with a plane undulator is studied in the linear approximation. Normal waves of the ribbon electron-oscillator beam are found. It is shown that the normal waves include a localization wave increasing in the axial direction and decreasing in the transverse direction. The problem of the plane wave diffraction on a layer of electron-oscillators is solved in the framework of the parabolic equation. It is proved that the asymptotic behavior of the field in the extended interaction space is determined by the excitation of an increasing wave canalized by the electron beam.

  10. Matter under extreme conditions probed by a seeded free-electron-laser

    SciTech Connect

    Bencivenga, F.; Principi, E.; Cucini, R.; Danailov, M. B.; Demidovich, A.; D’Amico, F.; Di Fonzo, S.; Gessini, A.; Kurdi, N.; Mahne, N.; Raimondi, L.; Zangrando, M.; Masciovecchio, C.; Giangrisostomi, E.; Battistoni, A.; Svetina, C.; Di Cicco, A.; Gunnella, R.; Hatada, K.; Filipponi, A.; and others

    2015-08-17

    FERMI is the first user dedicated seeded free-electron-laser (FEL) working in the extreme ultraviolet (XUV) and soft x-ray range. The EIS-TIMEX experimental end-station was availabe to external users since from the beginning of the user operation of the facility, in Dicember 2012. EIS-TIMEX has been conceived to exploit the unique properties of the FERMI source to study matter under extreme and metastable thermodynamic conditions. We hereby report on its basic parameters and applications, which includes very low jitter (i.e., high time resolution) pump-probe measurements.

  11. The analysis of Raman scattering in a free-electron laser with a rectangular hybrid wiggler

    SciTech Connect

    Kordbacheh, A. Shahsavand, M.

    2015-10-15

    A one dimensional theory of the stimulated Raman backscattering process in a free electron laser with rectangular hybrid wiggler (RHW) is analyzed. The dispersion relation in the rest frame of the electron beam and also a formula for the lab-frame spatial growth rate are derived. A numerical computation of the growth rate for RHW is conducted and a comparison with that for coaxial hybrid wiggler is made away from the resonance. The growth rate is found larger for the rectangular wiggler than for the coaxial wiggler. A much narrower magnetoresonance associated with the third spatial harmonic is also obtained compared to the first one.

  12. Low-voltage, megawatt free-electron lasers at a frequency near 300 GHz

    NASA Astrophysics Data System (ADS)

    Booske, J. H.; Granatstein, V. L.; Antonsen, T. M., Jr.; Destler, W. W.; Levush, B.

    1988-01-01

    Design procedures and beam transport feasibility experiments are discussed for a novel, millimeter-wave free electron laser (FEL) concept employing short period magnetic undulators and a sheet electron beam. The advantages of this concept include: (1) lower beam voltage compatible with thermionic Pierce gun technology and conventional power supplies (rather than electron accelerators); (2) a sheet electron beam geometry which enables high power operation without excessively high gun perveance; and (3) a streaming electron beam which is compatible with depressed collector beam energy recovery for enhancing overall system efficiency. Conceptual designs for pulsed and cw high power devices, and a cw low power device are presented.

  13. Compact free-electron laser resonators utilizing electron-transparent mirrors

    NASA Astrophysics Data System (ADS)

    Dipace, Antonio; Doria, Andrea; Gallerano, Gian P.; Kimmitt, Maurice F.; Raimondi, Pantaleone; Renieri, Alberto; Sabia, Elio

    1991-12-01

    The potential advantages and the physical properties of several electron-transparent mirrors (e.g., metal meshes, thin foils, pierced mirrors, and Bragg reflectors) to be used in infrared free-electron laser resonators are reviewed. The conditions under which the effect on the electron beam quality can be kept small are discussed, and experimental results on the angular spread produced by a 2.5-micron-thick metal mesh on a 5 MeV electron beam are presented. The experimental test of a resonator with two different electron transparent output couplers is reported.

  14. A Review of X-ray Free-Electron Laser Theory

    SciTech Connect

    Huang, Zhirong; Kim, Kwang-Je; /ANL, APS

    2006-12-18

    High-gain free-electron lasers (FELs) are being developed as extremely bright sources for a next-generation x-ray facility. In this paper, we review the basic theory of the startup, the exponential growth, and the saturation of the high-gain process, emphasizing the self-amplified spontaneous emission (SASE). The radiation characteristics of an x-ray FEL, including its transverse coherence, temporal characteristics, and harmonic content, are discussed. FEL performance in the presence of machine errors and undulator wakefields is examined. Various enhancement schemes through seeding and beam manipulations are summarized.

  15. Ptychographic imaging for the characterization of X-ray free-electron laser beams

    NASA Astrophysics Data System (ADS)

    Sala, S.; Daurer, BJ; Hantke, MF; Ekeberg, T.; Loh, ND; Maia, FRNC; Thibault, P.

    2017-06-01

    We present some preliminary results from a study aimed at the characterization of the wavefront of X-ray free electron laser (XFEL) beams in the same operation conditions as for single particle imaging (or flash X-ray imaging) experiments. The varying illumination produced by wavefront fluctuations between several pulses leads to a partially coherent average beam which can be decomposed into several coherent modes using ptychographic reconstruction algorithms. Such a decomposition can give insight into pulse-to-pulse variations of the wavefront. We discuss data collected at the Linac Coherent Light Source (LCLS) and FERMI.

  16. Efficiency enhancement in a Smith-Purcell free-electron laser

    NASA Astrophysics Data System (ADS)

    Shiozawa, T.; Sata, M.

    1995-01-01

    A systematic method to enhance the efficiency of energy transfer in a Smith-Purcell free-electron laser composed of a metallic grating and a relativistic electron beam is proposed. To maintain the synchronism between an electron beam and a slow electromagnetic wave propagated along a metallic grating, either one of the three grating parameters is adiabatically changed in the direction of wave propagation in accordance with the decrease in the drift velocity of the electron beam. The numerical simulation, which takes into account the reflection or scattering due to discontinuities in the grating parameters, demonstrates sufficient efficiency enhancement in energy transfer.

  17. Growth rate and start current in Smith-Purcell free-electron lasers

    SciTech Connect

    Li, D.; Imasaki, K.; Hangyo, M.; Tsunawaki, Y.; Yang, Z.; Wei, Y.; Miyamoto, S.; Asakawa, M. R.

    2012-05-07

    This letter reports a theory to calculate the growth rate and start current of a Smith-Purcell free-electron laser, which is a promising radiation source in the terahertz domain. A two-dimensional model was used to investigate the interaction between a sheet electron beam and the surface wave above a lamellar grating. After deriving the growth rate from the dispersion equation, the start current was carefully estimated by considering the power flow above the grating. The agreement between the predictions of our theory and the results from the particle-in-cell simulations is acceptable.

  18. Radiation control aspects of the civil construction for a high power free electron laser (FEL) facility

    SciTech Connect

    Dunn, T.; Neil, G.; Stapleton, G.

    1996-12-31

    The paper discusses some of the assumptions and methods employed for the control of ionizing radiation in the specifications for the civil construction of a planned free electron laser facility based on a 200 MeV, 5 mA superconducting recirculation electron accelerator. Consideration is given firstly to the way in which the underlying building configuration and siting aspects were optimized on the basis of the early assumptions of beam loss and radiation goals. The various design requirements for radiation protection are then considered, and how they were folded into an aesthetically pleasing and functional building.

  19. Radiation control aspects of the civil construction for a high power free electron laser (FEL) facility

    SciTech Connect

    Dunn, T.; Neil, G.; Stapleton, G.

    1997-02-01

    The paper discusses some of the assumptions and methods employed for the control of ionizing radiation in the specifications for the civil construction of a planned free electron laser facility based on a 200 MeV, 5 mA superconducting recirculation electron accelerator. Consideration is given firstly to the way in which the underlying building configuration and siting aspects were optimized on the basis of the early assumptions of beam loss and radiation goals. The various design requirements for radiation protection are then considered, and how they were folded into an aesthetically pleasing and functional building. {copyright} {ital 1997 American Institute of Physics.}

  20. Time resolved temperature measurement of polymer surface irradiated by mid-IR free electron laser

    NASA Astrophysics Data System (ADS)

    Araki, Mitsunori; Chiba, Tomoyuki; Oyama, Takahiro; Imai, Takayuki; Tsukiyama, Koichi

    2017-08-01

    We have developed the time-resolved temperature measurement system by using a radiation thermometer FLIR SC620. Temporal temperature profiles of an acrylic resin surface by the irradiation of infrared free electron laser (FEL) pulse were recorded in an 8 ms resolution to measure an instantaneous temperature rise and decay profile. Under the single-shot condition, a peak temperature defined as the temperature jump from the ambient temperature was found to be proportional to the absorbance. Under the multi-shot condition, the temperature accumulation was found to reach a roughly constant value where the supply and release of the heat is balanced.

  1. A review of x-ray free-electron laser theory.

    SciTech Connect

    Huang, Z.; Kim, K.-J.; Accelerator Systems Division; Stanford Linear Accelerator Center

    2007-03-01

    High-gain free-electron lasers (FELs) are being developed as extremely bright sources for a next-generation x-ray facility. In this paper, we review the basic theory of the start-up, the exponential growth, and the saturation of the high-gain process, emphasizing the self-amplified spontaneous emission. The radiation characteristics of an x-ray FEL, including its transverse coherence, temporal characteristics, and harmonic content, are discussed. FEL performance in the presence of machine errors and undulator wakefields is examined. Various enhancement schemes through seeding and beam manipulations are summarized.

  2. Efficient harmonic microbunching in a 7th-order inverse-free-electron laser interaction

    NASA Astrophysics Data System (ADS)

    Tochitsky, S. Ya.; Williams, O. B.; Musumeci, P.; Sung, C.; Haberberger, D. J.; Cook, A. M.; Rosenzweig, J. B.; Joshi, C.

    2009-05-01

    We have shown that a seventh-order inverse-free-electron laser (IFEL) interaction, where the radiation frequency is the seventh harmonic of the fundamental resonant frequency, can microbunch a beam of relativistic electrons inside an undulator. Using coherent transition radiation (CTR) emitted by the bunched 12.3 MeV beam as a diagnostic, strong microbunching of the beam is inferred from the observation of CTR at the first, second, and third harmonics of the seed 10μm radiation. Three-dimensional IFEL simulations show that the observed harmonic ratios can be explained only if transverse spatial distribution of the steepened bunched beam is taken into account.

  3. Design and Model Simulations of an Inverse Cerenkov Accelerator Using an Inverse Free Electron Laser Prebuncher

    NASA Astrophysics Data System (ADS)

    Kimura, W. D.; Babzien, M.; Cline, D. B.; Fiorito, R. B.; Gallardo, J. C.; Kusche, K. P.; Liu, Y.; Pogorelsky, I. V.; Quimby, D. C.; Rule, D. W.; Sandweiss, J.; Skaritka, J.; van Steenbergen, A.; Yakimenko, V.

    1997-05-01

    An experiment to use an inverse free electron laser (IFEL) to prebunch at optical wavelengths the electrons entering into an inverse Cerenkov accelerator (ICA) is being prepared at the BNL Accelerator Test Facility (ATF). The detailed design and simulations for this experiment will be presented. Microbunches on the order of 2 microns in length separated by 10.6 microns are predicted. Under the anticipated ATF conditions, space charge effects should not be an issue. Characterizing the microbunches and maintaining the proper phase relation between the IFEL and ICA modules are important issues that will also be discussed.

  4. Asymmetric two-bunch operation of free-electron laser and generation of inverse Compton photons

    NASA Astrophysics Data System (ADS)

    Ogawa, H.; Sei, N.; Yamada, K.

    2012-02-01

    Yield enhancement of high-energy photon pulses, which were generated via inverse Compton scattering of free-electron laser (FEL) pulses with electron pulses in relativistic motion, was achieved by an asymmetric two-bunch method. This method involves the use of two electron bunches recirculating in an electron storage ring for FEL oscillation with asymmetric bunch filling, and the generation of inverse Compton photon pulses at two collision points. The effects of the magnetic field of an undulator for FEL oscillation on the photon energy spectrum and photon yield were analyzed by Monte Carlo simulations and experiments.

  5. Numerical investigations on the effects of geometrical parameters on free electron laser instability

    NASA Astrophysics Data System (ADS)

    Sharma, B. S.; Jaiman, N. K.

    2008-12-01

    In this paper we numerically investigate the effects of various geometrical parameters of a backward wave oscillator (BWO), filled with a magnetized plasma of uniform density and driven by a mild relativistic solid electron beam, on the instability growth rate (Γ) of a free electron laser (FEL). The FEL instability is numerically calculated and the result is compared with the instability growth rate of an annular electron beam for the same set of parameters. The instability growth for a solid electron beam scales inversely to the seventh power of relativistic gamma factor γ0 and directly proportional to the corrugation amplitude.

  6. Integrated Numerical Experiments (INEX) and the Free-Electron Laser Physical Process Code (FELPPC)

    SciTech Connect

    Thode, L.E.; Chan, K.C.D.; Schmitt, M.J.; McKee, J.; Ostic, J.; Elliott, C.J.; McVey, B.D.

    1990-01-01

    The strong coupling of subsystem elements, such as the accelerator, wiggler, and optics, greatly complicates the understanding and design of a free electron laser (FEL), even at the conceptual level. Given the requirements for high-performance FELs, the strong coupling between the laser subsystems must be included to obtain a realistic picture of the potential operational capability. To address the strong coupling character of the FEL the concept of an Integrated Numerical Experiment (INEX) was proposed. Unique features of the INEX approach are consistency and numerical equivalence of experimental diagnostics. The equivalent numerical diagnostics mitigates the major problem of misinterpretation that often occurs when theoretical and experimental data are compared. The INEX approach has been applied to a large number of accelerator and FEL experiments. Overall, the agreement between INEX and the experiments is very good. Despite the success of INEX, the approach is difficult to apply to trade-off and initial design studies because of the significant manpower and computational requirements. On the other hand, INEX provides a base from which realistic accelerator, wiggler, and optics models can be developed. The Free Electron Laser Physical Process Code (FELPPC) includes models developed from INEX, provides coupling between the subsystems models and incorporates application models relevant to a specific trade-off or design study.

  7. High-intensity double-pulse X-ray free-electron laser

    SciTech Connect

    Marinelli, A.; Ratner, D.; Lutman, A. A.; Turner, J.; Welch, J.; Decker, F. J.; Loos, H.; Behrens, C.; Gilevich, S.; Miahnahri, A. A.; Vetter, S.; Maxwell, T. J.; Ding, Y.; Coffee, R.; Wakatsuki, S.; Huang, Z.

    2015-03-06

    The X-ray free-electron laser has opened a new era for photon science, improving the X-ray brightness by ten orders of magnitude over previously available sources. Similar to an optical laser, the spectral and temporal structure of the radiation pulses can be tailored to the specific needs of many experiments by accurately manipulating the lasing medium, that is, the electron beam. Here we report the generation of mJ-level two-colour hard X-ray pulses of few femtoseconds duration with an XFEL driven by twin electron bunches at the Linac Coherent Light Source. This performance represents an improvement of over an order of magnitude in peak power over state-of-the-art two-colour XFELs. The unprecedented intensity and temporal coherence of this new two-colour X-ray free-electron laser enable an entirely new set of scientific applications, ranging from X-ray pump/X-ray probe experiments to the imaging of complex biological samples with multiple wavelength anomalous dispersion.

  8. High-intensity double-pulse X-ray free-electron laser

    PubMed Central

    Marinelli, A.; Ratner, D.; Lutman, A. A.; Turner, J.; Welch, J.; Decker, F.-J.; Loos, H.; Behrens, C.; Gilevich, S.; Miahnahri, A. A.; Vetter, S.; Maxwell, T.J.; Ding, Y.; Coffee, R.; Wakatsuki, S.; Huang, Z.

    2015-01-01

    The X-ray free-electron laser has opened a new era for photon science, improving the X-ray brightness by ten orders of magnitude over previously available sources. Similar to an optical laser, the spectral and temporal structure of the radiation pulses can be tailored to the specific needs of many experiments by accurately manipulating the lasing medium, that is, the electron beam. Here we report the generation of mJ-level two-colour hard X-ray pulses of few femtoseconds duration with an XFEL driven by twin electron bunches at the Linac Coherent Light Source. This performance represents an improvement of over an order of magnitude in peak power over state-of-the-art two-colour XFELs. The unprecedented intensity and temporal coherence of this new two-colour X-ray free-electron laser enable an entirely new set of scientific applications, ranging from X-ray pump/X-ray probe experiments to the imaging of complex biological samples with multiple wavelength anomalous dispersion. PMID:25744344

  9. High-intensity double-pulse X-ray free-electron laser

    DOE PAGES

    Marinelli, A.; Ratner, D.; Lutman, A. A.; ...

    2015-03-06

    The X-ray free-electron laser has opened a new era for photon science, improving the X-ray brightness by ten orders of magnitude over previously available sources. Similar to an optical laser, the spectral and temporal structure of the radiation pulses can be tailored to the specific needs of many experiments by accurately manipulating the lasing medium, that is, the electron beam. Here we report the generation of mJ-level two-colour hard X-ray pulses of few femtoseconds duration with an XFEL driven by twin electron bunches at the Linac Coherent Light Source. This performance represents an improvement of over an order of magnitudemore » in peak power over state-of-the-art two-colour XFELs. The unprecedented intensity and temporal coherence of this new two-colour X-ray free-electron laser enable an entirely new set of scientific applications, ranging from X-ray pump/X-ray probe experiments to the imaging of complex biological samples with multiple wavelength anomalous dispersion.« less

  10. Integrated Numerical Experiments (INEX) and the Free-Electron Laser Physical Process Code (FELPPC)

    NASA Astrophysics Data System (ADS)

    Thode, L. E.; Chan, K. C. D.; Schmitt, M. J.; McKee, J.; Ostic, J.; Elliott, C. J.; McVey, B. D.

    The strong coupling of subsystem elements, such as the accelerator, wiggler, and optics, greatly complicates the understanding and design of a free electron laser (FEL), even at the conceptual level. Given the requirements for high-performance FELs, the strong coupling between the laser subsystems must be included to obtain a realistic picture of the potential operational capability. To address the strong coupling character of the FEL the concept of an Integrated Numerical Experiment (INEX) was proposed. Unique features of the INEX approach are consistency and numerical equivalence of experimental diagnostics. The equivalent numerical diagnostics mitigates the major problem of misinterpretation that often occurs when theoretical and experimental data are compared. The INEX approach has been applied to a large number of accelerator and FEL experiments. Overall, the agreement between INEX and the experiments is very good. Despite the success of INEX, the approach is difficult to apply to trade-off and initial design studies because of the significant manpower and computational requirements. On the other hand, INEX provides a base from which realistic accelerator, wiggler, and optics models can be developed. The Free Electron Laser Physical Process Code (FELPPC) includes models developed from INEX, provides coupling between the subsystems models and incorporates application models relevant to a specific trade-off or design study.

  11. Two-dimensional numerical model of the tapered wiggler free-electron laser

    SciTech Connect

    Prosnitz, D.; Haas, R.A.; Doss, S.; Gelinas, R.J.

    1982-08-31

    A two-dimensional numerical model of a high-gain (electron-beam power > input laser beam power) free-electron laser (FEL) has been constructed which includes the effects of diffraction, refraction, and off-axis electron-beam current density and wiggler field variations. In this model, laser beam propagation is governed by a paraxial wave equation with FEL source terms. Conventional resonant electron analysis is used to represent the trapping and deceleration of electrons by the electromagnetic field. The trapped electron-beam current density is forced to decrease as the size of the trapping potential decreases so that detrapping can be simulated. The variable-parameter wiggler field is chosen so that synchronism can be maintained at a single, arbitrary radial position. The magnetic field varies at other radial positions in accordance with Maxwell's equations.

  12. High gain harmonic generation free electron lasers enhanced by pseudoenergy bands

    NASA Astrophysics Data System (ADS)

    Tanaka, Takashi; Kinjo, Ryota

    2017-08-01

    We propose a new scheme for high gain harmonic generation free electron lasers (HGHG FELs), which is seeded by a pair of intersecting laser beams to interact with an electron beam in a modulator undulator located in a dispersive section. The interference of the laser beams gives rise to a two-dimensional modulation in the energy-time phase space because of a strong correlation between the electron energy and the position in the direction of dispersion. This eventually forms pseudoenergy bands in the electron beam, which result in efficient harmonic generation in HGHG FELs in a similar manner to the well-known scheme using the echo effects. The advantage of the proposed scheme is that the beam quality is less deteriorated than in other existing schemes.

  13. Probing vacuum birefringence using x-ray free electron and optical high-intensity lasers

    NASA Astrophysics Data System (ADS)

    Karbstein, Felix; Sundqvist, Chantal

    2016-07-01

    Vacuum birefringence is one of the most striking predictions of strong field quantum electrodynamics: Probe photons traversing a strong field region can indirectly sense the applied "pump" electromagnetic field via quantum fluctuations of virtual charged particles which couple to both pump and probe fields. This coupling is sensitive to the field alignment and can effectively result in two different indices of refraction for the probe photon polarization modes giving rise to a birefringence phenomenon. In this article, we perform a dedicated theoretical analysis of the proposed discovery experiment of vacuum birefringence at an x-ray free electron laser/optical high-intensity laser facility. Describing both pump and probe laser pulses realistically in terms of their macroscopic electromagnetic fields, we go beyond previous analyses by accounting for various effects not considered before in this context. Our study facilitates stringent quantitative predictions and optimizations of the signal in an actual experiment.

  14. Strongly aligned gas-phase molecules at free-electron lasers

    SciTech Connect

    Kierspel, Thomas; Wiese, Joss; Mullins, Terry; Robinson, Joseph; Aquila, Andy; Barty, Anton; Bean, Richard; Boll, Rebecca; Boutet, Sebastien; Bucksbaum, Philip; Chapman, Henry N.; Christensen, Lauge; Fry, Alan; Hunter, Mark; Koglin, Jason E.; Liang, Mengning; Mariani, Valerio; Morgan, Andrew; Natan, Adi; Petrovic, Vladimir; Rolles, Daniel; Rudenko, Artem; Schnorr, Kirsten; Stapelfeldt, Henrik; Stern, Stephan; Thogersen, Jan; Yoon, Chun Hong; Wang, Fenglin; Trippel, Sebastian; Kupper, Jochen

    2015-09-16

    Here, we demonstrate a novel experimental implementation to strongly align molecules at full repetition rates of free-electron lasers. We utilized the available in-house laser system at the coherent x-ray imaging beamline at the linac coherent light source. Chirped laser pulses, i.e., the direct output from the regenerative amplifier of the Ti:Sa chirped pulse amplification laser system, were used to strongly align 2, 5-diiodothiophene molecules in a molecular beam. The alignment laser pulses had pulse energies of a few mJ and a pulse duration of 94 ps. A degree of alignment of $\\langle {\\mathrm{cos}}^{2}{\\theta }_{2{\\rm{D}}}\\rangle =0.85$ was measured, limited by the intrinsic temperature of the molecular beam rather than by the available laser system. With the general availability of synchronized chirped-pulse-amplified near-infrared laser systems at short-wavelength laser facilities, our approach allows for the universal preparation of molecules tightly fixed in space for experiments with x-ray pulses.

  15. Strongly aligned gas-phase molecules at free-electron lasers

    DOE PAGES

    Kierspel, Thomas; Wiese, Joss; Mullins, Terry; ...

    2015-09-16

    Here, we demonstrate a novel experimental implementation to strongly align molecules at full repetition rates of free-electron lasers. We utilized the available in-house laser system at the coherent x-ray imaging beamline at the linac coherent light source. Chirped laser pulses, i.e., the direct output from the regenerative amplifier of the Ti:Sa chirped pulse amplification laser system, were used to strongly align 2, 5-diiodothiophene molecules in a molecular beam. The alignment laser pulses had pulse energies of a few mJ and a pulse duration of 94 ps. A degree of alignment ofmore » $$\\langle {\\mathrm{cos}}^{2}{\\theta }_{2{\\rm{D}}}\\rangle =0.85$$ was measured, limited by the intrinsic temperature of the molecular beam rather than by the available laser system. With the general availability of synchronized chirped-pulse-amplified near-infrared laser systems at short-wavelength laser facilities, our approach allows for the universal preparation of molecules tightly fixed in space for experiments with x-ray pulses.« less

  16. Equivalence between free-electron-laser oscillators and actively-mode-locked lasers: Detailed studies of temporal, spatiotemporal, and spectrotemporal dynamics

    SciTech Connect

    Bruni, C.; Legrand, T.; Szwaj, C.; Bielawski, S.; Couprie, M. E.

    2011-12-15

    We show experimentally and numerically that free-electron-laser (FEL) oscillators behave in a very similar way to conventional actively-mode-locked lasers. This stems from the similar structures of their underlying Haus equations. A comparative study of the temporal evolutions of the pulse train shapes and spatiotemporal regimes is performed on a Nd:YVO{sub 4} laser and a storage-ring free-electron laser. Furthermore, since direct observations of time-resolved pulse shapes and spectra are more accessible on free-electron lasers, the analogy also potentially enables one to investigate mode-locked laser dynamics using existing FEL facilities.

  17. Induction accelerators and free-electron lasers at LLNL: Beam Research Program

    SciTech Connect

    Briggs, R.J.

    1989-02-15

    Linear induction accelerators have been developed to produce pulses of charged particles at voltages exceeding the capabilities of single-stage, diode-type accelerators and at currents too high rf accelerators. In principle, one can accelerate charged particles to arbitrarily high voltages using a multistage induction machine. The advent of magnetic pulse power systems makes sustained operation at high repetition rates practical, and high-average-power capability is very likely to open up many new applications of induction machines. In Part A of this paper, we survey the US induction linac technology, emphasizing electron machines. We also give a simplified description of how induction machines couple energy to the electron beam to illustrate many general issues that designers of high-brightness and high-average-power induction linacs must consider. We give an example of the application of induction accelerator technology to the relativistic klystron, a power source for high-gradient accelerators. In Part B we address the application of LIAs to free-electron lasers. The multikiloampere peak currents available from linear induction accelerators make high-gain, free-electron laser amplifier configurations feasible. High extraction efficiencies in a single mass of the electron beam are possible if the wiggler parameters are appropriately ''tapered'', as recently demonstrated at millimeter wavelengths on the 4-MeV ELF facility. Key issues involved in extending the technology to shorter wavelengths and higher average powers are described. Current FEL experiments at LLNL are discussed. 5 refs., 16 figs.

  18. First Operation of a Free-Electron Laser Generating GW Power Radiation at 32-Nm Wavelength

    SciTech Connect

    Ayvazian, V.; Baboi, N.; Bahr, J.; Balandin, V.; Beutner, B.; Brandt, A.; Bohnet, I.; Bolzmann, A.; Brinkmann, R.; Brovko, O.I.; Carneiro, J.P.; Casalbuoni, S.; Castellano, M.; Castro, P.; Catani, L.; Chiadroni, E.; Choroba, S.; Cianchi, A.; Delsim-Hashemi, H.; Di Pirro, G.; Dohlus, M.; /Saclay /Wurzburg U. /BESSY, Berlin /CANDLE, Yerevan /Darmstadt, Tech. Hochsch. /DESY /DESY, Zeuthen /Fermilab /Hamburg U. /INFM, Padua /Frascati /INFN, Milan /INFN, Rome2 /Sofiya, Inst. Nucl. Res. /Dubna, JINR /Orsay, LAL /Max Born Inst., Berlin /SLAC

    2006-09-15

    Many scientific disciplines ranging from physics, chemistry and biology to material sciences, geophysics and medical diagnostics need a powerful X-ray source with pulse lengths in the femtosecond range. This would allow, for example, time-resolved observation of chemical reactions with atomic resolution. Such radiation of extreme intensity, and tunable over a wide range of wavelengths, can be accomplished using high-gain free-electron lasers (FEL). Here we present results of the first successful operation of an FEL at a wavelength of 32 nm, with ultra-short pulses (25 fs FWHM), a peak power at the Gigawatt level, and a high degree of transverse and longitudinal coherence. The experimental data are in full agreement with theory. This is the shortest wavelength achieved with an FEL to date and an important milestone towards a user facility designed for wavelengths down to 6 nm. With a peak brilliance exceeding the state-of-the-art of synchrotron radiation sources by seven orders of magnitude, this device opens a new field of experiments, and it paves the way towards sources with even shorter wavelengths, such as the Linac Coherent Light Source at Stanford, USA, and the European X-ray Free Electron Laser Facility in Hamburg, Germany.

  19. Coherent imaging of biological samples with femtosecond pulses at the free-electron laser FLASH

    NASA Astrophysics Data System (ADS)

    Mancuso, A. P.; Gorniak, Th; Staier, F.; Yefanov, O. M.; Barth, R.; Christophis, C.; Reime, B.; Gulden, J.; Singer, A.; Pettit, M. E.; Nisius, Th; Wilhein, Th; Gutt, C.; Grübel, G.; Guerassimova, N.; Treusch, R.; Feldhaus, J.; Eisebitt, S.; Weckert, E.; Grunze, M.; Rosenhahn, A.; Vartanyants, I. A.

    2010-03-01

    Coherent x-ray imaging represents a new window to imaging non-crystalline, biological specimens at unprecedented resolutions. The advent of free-electron lasers (FEL) allows extremely high flux densities to be delivered to a specimen resulting in stronger scattered signal from these samples to be measured. In the best case scenario, the diffraction pattern is measured before the sample is destroyed by these intense pulses, as the processes involved in radiation damage may be substantially slower than the pulse duration. In this case, the scattered signal can be interpreted and reconstructed to yield a faithful image of the sample at a resolution beyond the conventional radiation damage limit. We employ coherent x-ray diffraction imaging (CXDI) using the free-electron LASer in Hamburg (FLASH) in a non-destructive regime to compare images of a biological sample reconstructed using different, single, femtosecond pulses of FEL radiation. Furthermore, for the first time, we demonstrate CXDI, in-line holography and Fourier transform holography (FTH) of the same unicellular marine organism using an FEL and present diffraction data collected using the third harmonic of FLASH, reaching into the water window. We provide quantitative results for the resolution of the CXDI images as a function of pulse intensity, and compare this with the resolutions achieved with in-line holography and FTH.

  20. Room-temperature calorimeter for x-ray free-electron lasers.

    PubMed

    Tanaka, T; Kato, M; Saito, N; Tono, K; Yabashi, M; Ishikawa, T

    2015-09-01

    We have developed a room-temperature calorimeter for absolute radiant power measurements of x-ray free-electron lasers. This room-temperature calorimeter is an electrical substitution device based on the equivalence of electrical and radiant heating. Consequently, the measured radiant powers are traceable to electrical standards, i.e., the International System Units (SI). We demonstrated the performance of the room-temperature calorimeter by electrical power measurements (offline tests). In the offline tests, the room-temperature calorimeter was proven to be able to measure external powers up to at least 6.9 mW, which exceeds the upper limit (∼4 mW) of a cryogenic radiometer (the primary standard detector in Japan). In addition, measurement uncertainties of the room-temperature calorimeter were evaluated to be less than 1.0%, which is adequate for the radiant power measurements of x-ray free-electron lasers. An indirect comparison with the cryogenic radiometer was performed using a synchrotron radiation source to confirm the validity of the absolute radiant powers measured with the room-temperature calorimeter. The absolute radiant powers measured by the calorimeter agreed with those measured by the cryogenic radiometer within 0.6%, which is less than the relative standard uncertainty of the comparison (1.0%).

  1. Low-emittance thermionic-gun-based injector for a compact free-electron laser

    NASA Astrophysics Data System (ADS)

    Asaka, Takao; Ego, Hiroyasu; Hanaki, Hirohumi; Hara, Toru; Hasegawa, Taichi; Hasegawa, Teruaki; Inagaki, Takahiro; Kobayashi, Toshiaki; Kondo, Chikara; Maesaka, Hirokazu; Matsubara, Shinichi; Matsui, Sakuo; Ohshima, Takashi; Otake, Yuji; Sakurai, Tatsuyuki; Suzuki, Shinsuke; Tajiri, Yasuyuki; Tanaka, Shinichiro; Togawa, Kazuaki; Tanaka, Hitoshi

    2017-08-01

    A low-emittance thermionic-gun-based injector was developed for the x-ray free-electron laser (XFEL) facility known as the SPring-8 angstrom compact free-electron laser (SACLA). The thermionic-gun-based system has the advantages of maintainability, reliability, and stability over a photocathode radio-frequency (rf) gun because of its robust thermionic cathode. The basic performance of the injector prototype was confirmed at the SPring-8 compact self-amplified spontaneous emission source (SCSS) test accelerator, where stable FEL generation in an extreme ultraviolet wavelength range was demonstrated. The essential XFEL innovation is the achievement of a constant beam peak current of 3-4 kA, which is 10 times higher than that generated by the SCSS test accelerator, while maintaining a normalized-slice emittance below 1 mm mrad. Thus, the following five modifications were applied to the SACLA injector: (i) a nonlinear energy chirp correction; (ii) the optimization of the rf acceleration frequency; (iii) rf system stabilization; (iv) nondestructive beam monitoring; and (v) a geomagnetic field correction. The SACLA injector successfully achieved the target beam performance, which shows that a thermionic-gun-based injector is applicable to an XFEL accelerator system. This paper gives an overview of the SACLA injector and describes the physical and technical details, together with the electron beam performance obtained in the beam commissioning.

  2. High frequency limit of vacuum microelectronic grating free-electron laser

    SciTech Connect

    Goldstein, M.; Walsh, J.E.

    1995-12-31

    The dependencies that limit high frequency operation of a vacuum microelectronic grating free-electron laser are examined. The important parameters are identified as the electron beam energy, emittance, and generalized perveance. The scaling of power with emittance and frequency is studied in the far-infrared spectral range using a modified scanning electron microscope (SEM) and submillimeter diffraction gratings. The SEM is suited to the task of generating and positioning a low emittance (10{sup -2}{pi}-mm-mrad), low current (100 {mu}A), but high current density (50-500 A cm{sup -2}) electron beam. It has been used to demonstrate the spontaneous emission process known as the Smith-Purcell effect. A vacuum microelectronic grating free-electron laser has the potential of generating radiation throughout the entire far-infrared spectral range which extends from approximately 10 to 10{sup 3}{mu}m. An introduction to the theory, initial results, and details of the experiment are reported.

  3. Visible-infrared self-amplified spontaneous emission amplifier free electron laser undulator

    NASA Astrophysics Data System (ADS)

    Carr, Roger; Cornacchia, Max; Emma, Paul; Nuhn, Heinz-Dieter; Poling, Ben; Ruland, Robert; Johnson, Erik; Rakowsky, George; Skaritka, John; Lidia, Steve; Duffy, Pat; Libkind, Marcus; Frigola, Pedro; Murokh, Alex; Pellegrini, Claudio; Rosenzweig, James; Tremaine, Aaron

    2001-12-01

    The visible-infrared self-amplified spontaneous emission amplifier (VISA) free electron laser (FEL) is an experimental device designed to show self-amplified spontaneous emission (SASE) to saturation in the near infrared to visible light energy range. It generates a resonant wavelength output from 800-600 nm, so that silicon detectors may be used to characterize the optical properties of the FEL radiation. VISA is designed to show how SASE FEL theory corresponds with experiment in this wavelength range, using an electron beam with emittance close to that planned for the future Linear Coherent Light Source at SLAC. VISA comprises a 4 m pure permanent magnet undulator with four 99 cm segments, each of 55 periods, 18 mm long. The undulator has distributed focusing built into it, to reduce the average beta function of the 70-85 MeV electron beam to about 30 cm. There are four FODO cells per segment. The permanent magnet focusing lattice consists of blocks mounted on either side of the electron beam, in the undulator gap. The most important undulator error parameter for a free electron laser is the trajectory walk-off, or lack of overlap of the photon and electron beams. Using pulsed wire magnet measurements and magnet shimming, we were able to control trajectory walk-off to less than +/-50 μm per field gain length.

  4. Free electron lasers applied to VUV and soft X-ray physics of semiconductors

    NASA Astrophysics Data System (ADS)

    Lindau, I.

    1985-09-01

    The development of free electron lasers as a spectroscopic source would offer unique research opportunities and open up new avenues of research for the bulk and surface electronic properties of semiconductors. Existing spectroscopic techniques, based on conventional sources or synchrotron radiation, have contributed immensely to our understanding of the electronic structure of filled (photoemission) and empty (inverse photoemission) electronic levels. However, much less is known about the dynamic transient processes of electrons excited into empty states. A detailed understanding of both bulk (e.g., hot electron properties) and surface phenomena (e.g., photochemical reactions) are critically dependent on the transient dynamics of the excited electrons. The main assets of free electron laser radiation would be its high intensity, tunability, and time-structure. The tunability will provide selectivity for the final state energies into which the electrons are excited. Interesting resonance phenomena should be observed where interference occurs between different deexcitation channels. The time-structure will make it possible to study the time evolution of electron-electron, electron-phonon, electron-defect, etc., interactions of photoexcited carriers. The traditional optical probes (e.g., fluorescence) of hot carriers are bulk techniques. The photoelectron spectroscopy techniques are surface sensitive and provide a possible tool to study differences in relaxation phenomena for states at the surface versus states in the bulk. The surface sensitivity also makes it possible to study other dynamical processes on the surface: chemical reactions, chemi- and physi-sorption, and surface reconstructions.

  5. Microbunching-instability-induced sidebands in a seeded free-electron laser

    DOE PAGES

    Zhang, Zhen; Lindberg, Ryan; Fawley, William M.; ...

    2016-05-02

    Measurements of the multishot-averaged, soft x-ray, self-seeding spectrum at the LCLS free-electron laser often have a pedestal-like distribution around the seeded wavelength, which limits the spectral purity and can negatively affect some user applications not employing a post-undulator monochromator. In this paper, we study the origins of such pedestals, focusing on longitudinal phase space modulations produced by the microbunching instability upstream of the free-electron laser (FEL) undulator. Furthermore, we show from theory and numerical simulation that both energy and density modulations can induce sidebands in a high-gain, seeded FEL whose fractional strength typically grows as the square of the undulatormore » length. The results place a tight constraint on the longitudinal phase space uniformity of the electron beam for a seeded FEL, possibly requiring the amplitude of long-wavelength modulations to be much smaller than the typical incoherent energy spread if the output sideband power is to remain only a couple percent or less of the amplified seed power.« less

  6. Room-temperature calorimeter for x-ray free-electron lasers

    SciTech Connect

    Tanaka, T. Kato, M.; Saito, N.; Tono, K.; Yabashi, M.; Ishikawa, T.

    2015-09-15

    We have developed a room-temperature calorimeter for absolute radiant power measurements of x-ray free-electron lasers. This room-temperature calorimeter is an electrical substitution device based on the equivalence of electrical and radiant heating. Consequently, the measured radiant powers are traceable to electrical standards, i.e., the International System Units (SI). We demonstrated the performance of the room-temperature calorimeter by electrical power measurements (offline tests). In the offline tests, the room-temperature calorimeter was proven to be able to measure external powers up to at least 6.9 mW, which exceeds the upper limit (∼4 mW) of a cryogenic radiometer (the primary standard detector in Japan). In addition, measurement uncertainties of the room-temperature calorimeter were evaluated to be less than 1.0%, which is adequate for the radiant power measurements of x-ray free-electron lasers. An indirect comparison with the cryogenic radiometer was performed using a synchrotron radiation source to confirm the validity of the absolute radiant powers measured with the room-temperature calorimeter. The absolute radiant powers measured by the calorimeter agreed with those measured by the cryogenic radiometer within 0.6%, which is less than the relative standard uncertainty of the comparison (1.0%)

  7. Terawatt x-ray free-electron-laser optimization by transverse electron distribution shaping

    DOE PAGES

    Emma, C.; Wu, J.; Fang, K.; ...

    2014-11-03

    We study the dependence of the peak power of a 1.5 Å Terawatt (TW), tapered x-ray free-electron laser (FEL) on the transverse electron density distribution. Multidimensional optimization schemes for TW hard x-ray free-electron lasers are applied to the cases of transversely uniform and parabolic electron beam distributions and compared to a Gaussian distribution. The optimizations are performed for a 200 m undulator and a resonant wavelength of λr = 1.5 Å using the fully three-dimensional FEL particle code GENESIS. The study shows that the flatter transverse electron distributions enhance optical guiding in the tapered section of the undulator and increasemore » the maximum radiation power from a maximum of 1.56 TW for a transversely Gaussian beam to 2.26 TW for the parabolic case and 2.63 TW for the uniform case. Spectral data also shows a 30%–70% reduction in energy deposited in the sidebands for the uniform and parabolic beams compared with a Gaussian. An analysis of the transverse coherence of the radiation shows the coherence area to be much larger than the beam spotsize for all three distributions, making coherent diffraction imaging experiments possible.« less

  8. Analysis and comparison between electric and magnetic power couplers for accelerators in Free Electron Lasers (FEL)

    NASA Astrophysics Data System (ADS)

    Serpico, C.; Grudiev, A.; Vescovo, R.

    2016-10-01

    Free-electron lasers represent a new and exciting class of coherent optical sources possessing broad wavelength tunability and excellent optical-beam quality. The FERMI seeded free-electron laser (FEL), located at the Elettra laboratory in Trieste, is driven by a 200 m long, S-band linac: the high energy part of the linac is equipped with 6 m long backward traveling wave (BTW) structures. The structures have small iris radius and a nose cone geometry which allows for high gradient operation. Development of new high-gradient, S-band accelerating structures for the replacement of the existing BTWs is under consideration. This paper investigates two possible solutions for the RF power couplers suitable for a linac driven FEL which require reduced wakefields effects, high operating gradient and very high reliability. The first part of the manuscript focuses on the reduction of residual field asymmetries, while in the second analyzes RF performances, the peak surface fields and the expected breakdown rate. In the conclusion, two solutions are compared and pros and cons are highlighted.

  9. EUV Hartmann sensor for wavefront measurements at the Free-electron LASer in Hamburg

    NASA Astrophysics Data System (ADS)

    Flöter, Bernhard; Juranić, Pavle; Kapitzki, Svea; Keitel, Barbara; Mann, Klaus; Plönjes, Elke; Schäfer, Bernd; Tiedtke, Kai

    2010-08-01

    A compact, self-supporting Hartmann wavefront sensor was developed for the extreme ultraviolet (EUV) and soft x-ray range. The device is adapted to the characteristics of the Free-electron LASer in Hamburg (FLASH). It operates in a wavelength range from 6 to 30 nm with the capability to measure the wavefront quality of individual free-electron laser (FEL) pulses for beam characterization as well as for beamline alignment and monitoring behind user experiments. We report on online-Hartmann wavefront measurements at beamline BL2 with λ13.5 nm/90 accuracy for wavefront rms (wrms). The results were used to align the ellipsoidal focusing mirror at the beamline, decreasing the residual root mean square (rms) wavefront aberrations by more than a factor of 3 to 2.6 nm. The spot size of 31 μm (x) and 27 μm (y) full-width at half-maximum (FWHM) as well as other beam parameters evaluated from wavefront and intensity data are consistent with independent profile measurements in the focal region, employing both a high-resolution EUV camera and poly(methyl metacrylate) (PMMA) imprints.

  10. Batch crystallization of rhodopsin for structural dynamics using an X-ray free-electron laser

    SciTech Connect

    Wu, Wenting; Nogly, Przemyslaw; Rheinberger, Jan; Kick, Leonhard M.; Gati, Cornelius; Nelson, Garrett; Deupi, Xavier; Standfuss, Jörg; Schertler, Gebhard; Panneels, Valérie

    2015-06-27

    A new batch preparation method is presented for high-density micrometre-sized crystals of the G protein-coupled receptor rhodopsin for use in time-resolved serial femtosecond crystallography at an X-ray free-electron laser using a liquid jet. Rhodopsin is a membrane protein from the G protein-coupled receptor family. Together with its ligand retinal, it forms the visual pigment responsible for night vision. In order to perform ultrafast dynamics studies, a time-resolved serial femtosecond crystallography method is required owing to the nonreversible activation of rhodopsin. In such an approach, microcrystals in suspension are delivered into the X-ray pulses of an X-ray free-electron laser (XFEL) after a precise photoactivation delay. Here, a millilitre batch production of high-density microcrystals was developed by four methodical conversion steps starting from known vapour-diffusion crystallization protocols: (i) screening the low-salt crystallization conditions preferred for serial crystallography by vapour diffusion, (ii) optimization of batch crystallization, (iii) testing the crystal size and quality using second-harmonic generation (SHG) imaging and X-ray powder diffraction and (iv) production of millilitres of rhodopsin crystal suspension in batches for serial crystallography tests; these crystals diffracted at an XFEL at the Linac Coherent Light Source using a liquid-jet setup.

  11. Sequential single shot X-ray photon correlation spectroscopy at the SACLA free electron laser

    DOE PAGES

    Lehmkühler, Felix; Kwaśniewski, Paweł; Roseker, Wojciech; ...

    2015-11-27

    In this study, hard X-ray free electron lasers allow for the first time to access dynamics of condensed matter samples ranging from femtoseconds to several hundred seconds. In particular, the exceptional large transverse coherence of the X-ray pulses and the high time-averaged flux promises to reach time and length scales that have not been accessible up to now with storage ring based sources. However, due to the fluctuations originating from the stochastic nature of the self-amplified spontaneous emission (SASE) process the application of well established techniques such as X-ray photon correlation spectroscopy (XPCS) is challenging. Here we demonstrate a single-shotmore » based sequential XPCS study on a colloidal suspension with a relaxation time comparable to the SACLA free-electron laser pulse repetition rate. High quality correlation functions could be extracted without any indications for sample damage. This opens the way for systematic sequential XPCS experiments at FEL sources.« less

  12. High-energy density experiments on planetary materials using high-power lasers and X-ray free electron laser

    NASA Astrophysics Data System (ADS)

    Ozaki, Norimasa

    2015-06-01

    Laser-driven dynamic compression allows us to investigate the behavior of planetary and exoplanetary materials at extreme conditions. Our high-energy density (HED) experiments for applications to planetary sciences began over five years ago. We measured the equation-of-state of cryogenic liquid hydrogen under laser-shock compression up to 55 GPa. Since then, various materials constituting the icy giant planets and the Earth-like planets have been studied using laser-driven dynamic compression techniques. Pressure-volume-temperature EOS data and optical property data of water and molecular mixtures were obtained at the planetary/exoplanetary interior conditions. Silicates and oxides data show interesting behaviors in the warm-dense matter regime due to their phase transformations. Most recently the structural changes of iron were observed for understanding the kinetics under the bcc-hcp transformation phenomena on a new HED science platform coupling power-lasers and the X-ray free electron laser (SACLA). This work was performed under the joint research project at the Institute of Laser Engineering, Osaka University. It was partially supported by a Grant-in-Aid for Scientific Research (Grant Nos. 20654042, 22224012, 23540556, and 24103507) and also by grants from the Core-to-Core Program of JSPS on International Alliance for Material Science in Extreme States with High Power Laser and XFEL, and the X-ray Free Electron Laser Priority Strategy Program of MEXT.

  13. Absorber for wakefield interference management at the entrance of the wiggler of a free electron laser

    DOEpatents

    Marchlik, Matthew; Biallas, George Herman

    2017-03-07

    A method for managing the broad band microwave and TeraHertz (THz) radiation in a free electron laser (FEL) having a wiggler producing power in the electromagnetic spectrum. The method includes placement of broadband microwave and TeraHertz (THz) radiation absorbers on the upstream end of the wiggler. The absorbers dampen the bounced back, broad band microwave and THz radiation returning from the surfaces outside the nose of the cookie-cutter and thus preventing broadening of the electron beam pulse's narrow longitudinal energy distribution. Broadening diminishes the ultimate laser power from the wiggler. The broadband microwave and THz radiation absorbers are placed on either side of the slot in the cookie-cutter that shapes the wake field wave of the electron pulse to the slot shape of the wiggler chamber aperture. The broad band microwave and THz radiation absorber is preferably a non-porous pyrolytic grade of graphite with small grain size.

  14. Electron Bunch Timing with Femtosecond Precision in a Superconducting Free-Electron Laser

    SciTech Connect

    Loehl, F.; Arsov, V.; Felber, M.; Hacker, K.; Lorbeer, B.; Ludwig, F.; Matthiesen, K.-H.; Schlarb, H.; Schmidt, B.; Winter, A.; Jalmuzna, W.; Schmueser, P.; Schulz, S.; Zemella, J.; Szewinski, J.

    2010-04-09

    High-gain free-electron lasers (FELs) are capable of generating femtosecond x-ray pulses with peak brilliances many orders of magnitude higher than at other existing x-ray sources. In order to fully exploit the opportunities offered by these femtosecond light pulses in time-resolved experiments, an unprecedented synchronization accuracy is required. In this Letter, we distributed the pulse train of a mode-locked fiber laser with femtosecond stability to different locations in the linear accelerator of the soft x-ray FEL FLASH. A novel electro-optic detection scheme was applied to measure the electron bunch arrival time with an as yet unrivaled precision of 6 fs (rms). With two beam-based feedback systems we succeeded in stabilizing both the arrival time and the electron bunch compression process within two magnetic chicanes, yielding a significant reduction of the FEL pulse energy jitter.

  15. Status report on Jefferson Lab`s high-power infrared free-electron laser

    SciTech Connect

    Bohn, C.L.

    1997-10-01

    Jefferson Lab is building a free-electron laser to produce tunable, continuous-wave (cw), kW-level light at 3-6 {mu}m wavelength. A superconducting accelerator will drive the laser, and a transport lattice will recirculate the beam back through the accelerator for energy recovery. Space charge in the injector and coherent synchrotron radiation in magnetic bends will be present, and the machine is instrumented to study these phenomena during commissioning. The wiggler and optical cavity are conventional; however, significant analysis and testing was needed to ensure mirror heating at 1 kW of outcoupled power would not impede performance. The FEL is being installed in its own facility, and installation will be finished in Fall 1997. This paper surveys the machine, the status of its construction, and plans for its commissioning.

  16. Experiments in transmission of free electron laser radiation by flexible waveguides

    NASA Astrophysics Data System (ADS)

    Gannot, Israel; Waynant, Ronald W.; Dror, Jacob; Inberg, Alexandra; Croitoru, Nathan I.

    1996-04-01

    The free electron laser (FEL) is a unique laser which is tunable over a wide segment of the spectrum. Its tunability can open a wide range of applications in medicine -- both surgical and diagnostic. A delivery device such as a waveguide or a fiber, flexible enough, which will be coupled to its outlet, will enable maneuvering the beam conveniently at the operating site. The greatest obstacle for such a fiber or waveguide is the high peak power of several MWatts that characterize the beam and the wide range of wavelengths. Flexible hollow waveguides made of either a fused silica or a Teflon tubing, internally coated with reflecting/refracting layers, were used in experiments at 3 FEL centers in the U.S. A segment of the mid IR spectrum (between 6 and 7 micrometers). Results of the beam shape (both temporal and spatial) and transmission measurements have proven the potential of this waveguide for transmission of FEL radiation.

  17. Atomic processes modeling of X-ray free electron laser produced plasmas using SCFLY code

    NASA Astrophysics Data System (ADS)

    Chung, H.-K.; Cho, B. I.; Ciricosta, O.; Vinko, S. M.; Wark, J. S.; Lee, R. W.

    2017-03-01

    With the development of X-ray free electron lasers (XFEL), a novel state of matter of highly transient and non-equilibrium plasma has been created in laboratories. As high intensity X-ray laser beams interact with a solid density target, electrons are ionized from inner-shell orbitals and these electrons and XFEL photons create dense and finite temperature plasmas. In order to study atomic processes in XFEL driven plasmas, the atomic kinetics model SCFLY containing an extensive set of configurations needed for solid density plasmas was applied to study atomic processes of XFEL driven systems. The code accepts the time-dependent conditions of the XFEL as input parameters, and computes time-dependent population distributions and ionization distributions self-consistently with electron temperatures and densities assuming an instantaneous equilibration of electron energies. The methods and assumptions in the atomic kinetics model and unique aspects of atomic processes in XFEL driven plasmas are described.

  18. Suppression of microbunching instability using bending magnets in free-electron-laser linacs.

    PubMed

    Qiang, Ji; Mitchell, Chad E; Venturini, Marco

    2013-08-02

    The microbunching instability driven by collective effects of the beam inside an accelerator can significantly degrade the final electron beam quality for free electron laser (FEL) radiation. In this Letter, we propose an inexpensive scheme to suppress such an instability in accelerators for next generation FEL light sources. Instead of using an expensive device such as a laser heater or RF deflecting cavities, this scheme uses longitudinal mixing associated with the transverse spread of the beam through bending magnets inside the accelerator transport system to suppress the instability. The final uncorrelated energy spread increases roughly by the current compression factor, which is important in seeded FEL schemes in order to achieve high harmonic short-wavelength x-ray radiation.

  19. Experimental Investigation of Superradiance in a Tapered Free-Electron Laser Amplifier

    SciTech Connect

    Hidaka, Y.; She, Y.; Murphy, J.B.; Podobedov, B.; Seletskiy, S.; Yang, X.

    2011-03-28

    We report experimental studies of the effect of undulator tapering on superradiance in a single-pass high-gain free-electron laser (FEL) amplifier. The experiments were performed at the Source Development Laboratory (SDL) of National Synchrotron Light Source (NSLS). Efficiency was nearly tripled with tapering. Both the temporal and spectral properties of the superradiant FEL along the uniform and tapered undulator were experimentally characterized using frequency-resolved optical gating (FROG) images. Numerical studies predicted pulse broadening and spectral cleaning by undulator tapering Pulse broadening was experimentally verified. However, spectral cleanliness degraded with tapering. We have performed first experiments with a tapered undulator and a short seed laser pulse. Pulse broadening with tapering expected from simulations was experimentally confirmed. However, the experimentally obtained spectra degraded with tapering, whereas the simulations predicted improvement. A further numerical study is under way to resolve this issue.

  20. Simplified model for fast optimization of a free-electron laser oscillator

    NASA Astrophysics Data System (ADS)

    Li, Kai; Song, Minghao; Deng, Haixiao

    2017-03-01

    A simplified one-dimensional theoretical model for free-electron laser oscillator (FELO) calculation which reserves the main physics is proposed. Instead of using traditional macroparticles sampling method, the theoretical model takes advantage of low gain theory to calculate the optical power single-pass gain in the undulator analytically, and some reasonable approximations are made to simplify the calculation of power growth in the cavity. The theoretical analysis of single-pass gain, power growth, time-dependent laser profile evolution and cavity desynchronism are accomplished more efficiently. We present the results of infrared wavelength FELO and X-ray FELO with the new model. The results are validated by simulation with GENESIS and OPC.

  1. Comparison of short pulse generation schemes for a soft x-ray free electron laser

    NASA Astrophysics Data System (ADS)

    Martin, I. P. S.; Bartolini, R.

    2011-03-01

    In this paper we study the performance of two complementary short pulse generation schemes as applied to a soft x-ray free electron laser. The first scheme, recently proposed by Saldin et al., makes use of a laser pulse consisting of only a few optical cycles to give an energy chirp to a short section of an electron bunch and tapers the main radiator undulator in order to compensate the chirped region. The second scheme investigated takes a low-charge, high brightness electron bunch and compresses it to ˜1fs in order to operate in the so-called “single-spike” regime. We perform start-to-end simulations of both these schemes, assess the sensitivity of each scheme to realistic jitter sources, and provide a direct comparison of the respective strengths and drawbacks.

  2. Multi-range free-electron laser with a pair of dielectric multilayer mirrors

    NASA Astrophysics Data System (ADS)

    Sei, Norihiro; Ogawa, Hiroshi; Yamada, Kawakatsu

    2012-10-01

    We report the experimental achievement of a free-electron laser in three wavelength regions, mid-infrared, near-infrared, and visible, using a pair of dielectric multilayer mirrors in the storage ring NIJI-IV. Dielectric multilayer mirrors can have high reflectivity at wavelength regions corresponding to higher-diffraction orders of the target wavelength. A narrowing of the relative bandwidth of the dielectric multilayer mirrors was observed in the higher-diffraction orders of the target wavelength and was found to be caused by high diffraction and carbon contamination. Our experimental results will be applied to development of a multi-rang laser that have a gain in a wade wavelength region.

  3. An optical parametric chirped-pulse amplifier for seeding high repetition rate free-electron lasers

    SciTech Connect

    Höppner, H.; Tanikawa, T.; Schulz, M.; Riedel, R.; Teubner, U.; Faatz, B.; Tavella, F.

    2015-05-15

    High repetition rate free-electron lasers (FEL), producing highly intense extreme ultraviolet and x-ray pulses, require new high power tunable femtosecond lasers for FEL seeding and FEL pump-probe experiments. A tunable, 112 W (burst mode) optical parametric chirped-pulse amplifier (OPCPA) is demonstrated with center frequencies ranging from 720–900 nm, pulse energies up to 1.12 mJ and a pulse duration of 30 fs at a repetition rate of 100 kHz. Since the power scalability of this OPCPA is limited by the OPCPA-pump amplifier, we also demonstrate a 6.7–13.7 kW (burst mode) thin-disk OPCPA-pump amplifier, increasing the possible OPCPA output power to many hundreds of watts. Furthermore, third and fourth harmonic generation experiments are performed and the results are used to simulate a seeded FEL with high-gain harmonic generation.

  4. Time-resolved protein nanocrystallography using an X-ray free-electron laser

    PubMed Central

    Aquila, Andrew; Hunter, Mark S.; Doak, R. Bruce; Kirian, Richard A.; Fromme, Petra; White, Thomas A.; Andreasson, Jakob; Arnlund, David; Bajt, Saša; Barends, Thomas R. M.; Barthelmess, Miriam; Bogan, Michael J.; Bostedt, Christoph; Bottin, Hervé; Bozek, John D.; Caleman, Carl; Coppola, Nicola; Davidsson, Jan; DePonte, Daniel P.; Elser, Veit; Epp, Sascha W.; Erk, Benjamin; Fleckenstein, Holger; Foucar, Lutz; Frank, Matthias; Fromme, Raimund; Graafsma, Heinz; Grotjohann, Ingo; Gumprecht, Lars; Hajdu, Janos; Hampton, Christina Y.; Hartmann, Andreas; Hartmann, Robert; Hau-Riege, Stefan; Hauser, Günter; Hirsemann, Helmut; Holl, Peter; Holton, James M.; Hömke, André; Johansson, Linda; Kimmel, Nils; Kassemeyer, Stephan; Krasniqi, Faton; Kühnel, Kai-Uwe; Liang, Mengning; Lomb, Lukas; Malmerberg, Erik; Marchesini, Stefano; Martin, Andrew V.; Maia, Filipe R.N.C.; Messerschmidt, Marc; Nass, Karol; Reich, Christian; Neutze, Richard; Rolles, Daniel; Rudek, Benedikt; Rudenko, Artem; Schlichting, Ilme; Schmidt, Carlo; Schmidt, Kevin E.; Schulz, Joachim; Seibert, M. Marvin; Shoeman, Robert L.; Sierra, Raymond; Soltau, Heike; Starodub, Dmitri; Stellato, Francesco; Stern, Stephan; Strüder, Lothar; Timneanu, Nicusor; Ullrich, Joachim; Wang, Xiaoyu; Williams, Garth J.; Weidenspointner, Georg; Weierstall, Uwe; Wunderer, Cornelia; Barty, Anton; Spence, John C. H.; Chapman, Henry N.

    2012-01-01

    We demonstrate the use of an X-ray free electron laser synchronized with an optical pump laser to obtain X-ray diffraction snapshots from the photoactivated states of large membrane protein complexes in the form of nanocrystals flowing in a liquid jet. Light-induced changes of Photosystem I-Ferredoxin co-crystals were observed at time delays of 5 to 10 µs after excitation. The result correlates with the microsecond kinetics of electron transfer from Photosystem I to ferredoxin. The undocking process that follows the electron transfer leads to large rearrangements in the crystals that will terminally lead to the disintegration of the crystals. We describe the experimental setup and obtain the first time-resolved femtosecond serial X-ray crystallography results from an irreversible photo-chemical reaction at the Linac Coherent Light Source. This technique opens the door to time-resolved structural studies of reaction dynamics in biological systems. PMID:22330507

  5. A high-power free electron laser using a short rayleigh length

    SciTech Connect

    William Colson; Alan Todd; George Neil

    2004-09-01

    Free electron lasers have always had the potential for high average power, since the laser medium cannot be damaged and is transparent to all wavelengths while the exhaust heat is removed at the speed of light. At MW power levels, the resonator mirrors of the oscillator are vulnerable to damage because of the small beam size in the undulator. We present a description of an FEL that uses a resonator with a short Rayleigh length in order to increase the mode area at the mirrors and reduce the intensity. The corresponding undulator must also be short. The whole FEL system is designed to be compact and efficient, producing about 1 MW of power at 1 mu-m infrared wavelength using an electron beam of about 140 MeV with about 0.6A of recirculating average current.

  6. Nanofocusing of hard X-ray free electron laser pulses using diamond based Fresnel zone plates.

    PubMed

    David, C; Gorelick, S; Rutishauser, S; Krzywinski, J; Vila-Comamala, J; Guzenko, V A; Bunk, O; Färm, E; Ritala, M; Cammarata, M; Fritz, D M; Barrett, R; Samoylova, L; Grünert, J; Sinn, H

    2011-01-01

    A growing number of X-ray sources based on the free-electron laser (XFEL) principle are presently under construction or have recently started operation. The intense, ultrashort pulses of these sources will enable new insights in many different fields of science. A key problem is to provide x-ray optical elements capable of collecting the largest possible fraction of the radiation and to focus into the smallest possible focus. As a key step towards this goal, we demonstrate here the first nanofocusing of hard XFEL pulses. We developed diamond based Fresnel zone plates capable of withstanding the full beam of the world's most powerful x-ray laser. Using an imprint technique, we measured the focal spot size, which was limited to 320 nm FWHM by the spectral band width of the source. A peak power density in the focal spot of 4×10(17)W/cm(2) was obtained at 70 fs pulse length.

  7. Ultrafast time dynamics studies of periodic lattices with free electron laser radiation

    SciTech Connect

    Quevedo, W.; Busse, G.; Hallmann, J.; More, R.; Petri, M.; Rajkovic, I.; Krasniqi, F.; Rudenko, A.; Tschentscher, T.; Stojanovic, N.; Duesterer, S.; Treusch, R.; Tolkiehn, M.; Techert, S.

    2012-11-01

    It has been proposed that radiation from free electron laser (FEL) at Hamburg (FLASH) can be used for ultrafast time-resolved x-ray diffraction experiments based on the near-infrared (NIR) pump/FEL probe scheme. Here, investigation probing the ultrafast structural dynamics of periodic nano-crystalline organic matter (silver behenate) with such a scheme is reported. Excitation with a femtosecond NIR laser leads to an ultrafast lattice modification which time evolution has been studied through the scattering of vacuum ultraviolet FEL pulses. The found effect last for 6 ps and underpins the possibility for studying nanoperiodic dynamics down to the FEL source time resolution. Furthermore, the possibility of extending the use of silver behenate (AgBh) as a wavelength and temporal calibration tool for experiments with soft x-ray/FEL sources is suggested.

  8. A High-Average-Power Free Electron Laser for Microfabrication and Surface Applications

    NASA Technical Reports Server (NTRS)

    Dylla, H. F.; Benson, S.; Bisognano, J.; Bohn, C. L.; Cardman, L.; Engwall, D.; Fugitt, J.; Jordan, K.; Kehne, D.; Li, Z.; Liu, H.; Merminga, L.; Neil, G. R.; Neuffer, D.; Shinn, M.; Sinclair, C.; Wiseman, M.; Brillson, L. J.; Henkel, D. P.; Helvajian, H.; Kelley, M. J.; Nair, Shanti

    1995-01-01

    CEBAF has developed a comprehensive conceptual design of an industrial user facility based on a kilowatt ultraviolet (UV) (160-1000 mm) and infrared (IR) (2-25 micron) free electron laser (FEL) driven by a recirculating, energy recovering 200 MeV superconducting radio frequency (SRF) accelerator. FEL users, CEBAF's partners in the Lase Processing Consortium, including AT&T, DuPont, IBM, Northrop Grumman, 3M, and Xerox, are developing applications such as metal, ceramic, and electronic material micro-fabrication and polymer and metal surface processing, with the overall effort leading to later scale-up to industrial systems at 50-100 kW. Representative applications are described. The proposed high-average-power FEL overcomes limitations of conventional laser sources in available power, cost-effectiveness, tunability, and pulse structure.

  9. Temperature alterations of infrared light absorption by cartilage and cornea under free-electron laser radiation

    NASA Astrophysics Data System (ADS)

    Sobol, Emil N.; Sviridov, Alexander P.; Kitai, Moishe S.; Edwards, Glenn S.

    2003-05-01

    Like pure water, the water incorporated into cartilage and cornea tissue shows a pronounced dependence of the absorption coefficient on temperature. Alteration of the temperature by radiation with an IR free-electron laser was studied by use of a pulsed photothermal radiometric technique. A computation algorithm was modified to take into account the real IR absorption spectra of the tissue and the spectral sensitivity of the IR detector used. The absorption coefficients for several wavelengths within the 2.9- and 6.1- μm water absorption bands have been determined for various laser pulse energies. It is shown that the absorption coefficient for cartilage decreases at temperatures higher than 50 °C owing to thermal alterations of water-water and water-biopolymer interactions.

  10. Time-resolved protein nanocrystallography using an X-ray free-electron laser.

    PubMed

    Aquila, Andrew; Hunter, Mark S; Doak, R Bruce; Kirian, Richard A; Fromme, Petra; White, Thomas A; Andreasson, Jakob; Arnlund, David; Bajt, Saša; Barends, Thomas R M; Barthelmess, Miriam; Bogan, Michael J; Bostedt, Christoph; Bottin, Hervé; Bozek, John D; Caleman, Carl; Coppola, Nicola; Davidsson, Jan; DePonte, Daniel P; Elser, Veit; Epp, Sascha W; Erk, Benjamin; Fleckenstein, Holger; Foucar, Lutz; Frank, Matthias; Fromme, Raimund; Graafsma, Heinz; Grotjohann, Ingo; Gumprecht, Lars; Hajdu, Janos; Hampton, Christina Y; Hartmann, Andreas; Hartmann, Robert; Hau-Riege, Stefan; Hauser, Günter; Hirsemann, Helmut; Holl, Peter; Holton, James M; Hömke, André; Johansson, Linda; Kimmel, Nils; Kassemeyer, Stephan; Krasniqi, Faton; Kühnel, Kai-Uwe; Liang, Mengning; Lomb, Lukas; Malmerberg, Erik; Marchesini, Stefano; Martin, Andrew V; Maia, Filipe R N C; Messerschmidt, Marc; Nass, Karol; Reich, Christian; Neutze, Richard; Rolles, Daniel; Rudek, Benedikt; Rudenko, Artem; Schlichting, Ilme; Schmidt, Carlo; Schmidt, Kevin E; Schulz, Joachim; Seibert, M Marvin; Shoeman, Robert L; Sierra, Raymond; Soltau, Heike; Starodub, Dmitri; Stellato, Francesco; Stern, Stephan; Strüder, Lothar; Timneanu, Nicusor; Ullrich, Joachim; Wang, Xiaoyu; Williams, Garth J; Weidenspointner, Georg; Weierstall, Uwe; Wunderer, Cornelia; Barty, Anton; Spence, John C H; Chapman, Henry N

    2012-01-30

    We demonstrate the use of an X-ray free electron laser synchronized with an optical pump laser to obtain X-ray diffraction snapshots from the photoactivated states of large membrane protein complexes in the form of nanocrystals flowing in a liquid jet. Light-induced changes of Photosystem I-Ferredoxin co-crystals were observed at time delays of 5 to 10 µs after excitation. The result correlates with the microsecond kinetics of electron transfer from Photosystem I to ferredoxin. The undocking process that follows the electron transfer leads to large rearrangements in the crystals that will terminally lead to the disintegration of the crystals. We describe the experimental setup and obtain the first time-resolved femtosecond serial X-ray crystallography results from an irreversible photo-chemical reaction at the Linac Coherent Light Source. This technique opens the door to time-resolved structural studies of reaction dynamics in biological systems.

  11. Electron bunch timing with femtosecond precision in a superconducting free-electron laser.

    PubMed

    Löhl, F; Arsov, V; Felber, M; Hacker, K; Jalmuzna, W; Lorbeer, B; Ludwig, F; Matthiesen, K-H; Schlarb, H; Schmidt, B; Schmüser, P; Schulz, S; Szewinski, J; Winter, A; Zemella, J

    2010-04-09

    High-gain free-electron lasers (FELs) are capable of generating femtosecond x-ray pulses with peak brilliances many orders of magnitude higher than at other existing x-ray sources. In order to fully exploit the opportunities offered by these femtosecond light pulses in time-resolved experiments, an unprecedented synchronization accuracy is required. In this Letter, we distributed the pulse train of a mode-locked fiber laser with femtosecond stability to different locations in the linear accelerator of the soft x-ray FEL FLASH. A novel electro-optic detection scheme was applied to measure the electron bunch arrival time with an as yet unrivaled precision of 6 fs (rms). With two beam-based feedback systems we succeeded in stabilizing both the arrival time and the electron bunch compression process within two magnetic chicanes, yielding a significant reduction of the FEL pulse energy jitter.

  12. Generation of high harmonic free electron laser with phase-merging effect

    NASA Astrophysics Data System (ADS)

    Li, Heting; Jia, Qika; Zhao, Zhouyu

    2017-03-01

    An easy-to-implement scheme is proposed to produce the longitudinal electron bunch density modulation with phase-merging phenomenon. In this scheme an electron bunch is firstly transversely dispersed in a modified dogleg to generate the exact dependence of electron energy on the transverse position, then it is modulated in a normal modulator. After travelling through a modified chicane with specially designed transfer matrix elements, the density modulation with phase-merging effect is generated which contains high harmonic components of the seed laser. We present theoretical analysis and numerical simulations for seeded soft x-ray free-electron laser. The results demonstrate that this technique can significantly enhance the frequency up-conversion efficiency and allow a seeded FEL operating at very high harmonics.

  13. A Proof-of-Principle Echo-enabled Harmonic Generation Free Electron Laser Experiment at SLAC

    SciTech Connect

    Pernet, Pierre-Louis

    2010-06-24

    With the advent of X-ray Free Electron Lasers (FELs), new methods have been developed to extend capabilities at short wavelengths beyond Self-Amplified Spontaneous Emission (SASE). In particular, seeding of a FEL allows for temporal control of the radiation pulse and increases the peak brightness by orders of magnitude. Most recently, Gennady Stupakov and colleagues at SLAC proposed a new technique: Echo-Enabled Harmonic Generation (EEHG). Here a laser microbunches the beam in an undulator and the beam is sheared in a chicane. This process is repeated with a second laser, undulator and chicane. The interplay between these allows a seeding of the X-ray laser up to the 100th harmonic of the first laser. After introducing the physics of FELs and the EEHG seeding technique, we describe contributions to the experimental effort. We will present detailed studies of the experiment including the choice of parameters and their optimization, the emittance effect, spontaneous emission in the undulators, the second laser phase effect, and measurements of the jitter between RF stations. Finally, the status and preliminary results of the Echo-7 experiment will be outlined.

  14. Native phasing of x-ray free-electron laser data for a G protein–coupled receptor

    PubMed Central

    Batyuk, Alexander; Galli, Lorenzo; Ishchenko, Andrii; Han, Gye Won; Gati, Cornelius; Popov, Petr A.; Lee, Ming-Yue; Stauch, Benjamin; White, Thomas A.; Barty, Anton; Aquila, Andrew; Hunter, Mark S.; Liang, Mengning; Boutet, Sébastien; Pu, Mengchen; Liu, Zhi-jie; Nelson, Garrett; James, Daniel; Li, Chufeng; Zhao, Yun; Spence, John C. H.; Liu, Wei; Fromme, Petra; Katritch, Vsevolod; Weierstall, Uwe; Stevens, Raymond C.; Cherezov, Vadim

    2016-01-01

    Serial femtosecond crystallography (SFX) takes advantage of extremely bright and ultrashort pulses produced by x-ray free-electron lasers (XFELs), allowing for the collection of high-resolution diffraction intensities from micrometer-sized crystals at room temperature with minimal radiation damage, using the principle of “diffraction-before-destruction.” However, de novo structure factor phase determination using XFELs has been difficult so far. We demonstrate the ability to solve the crystallographic phase problem for SFX data collected with an XFEL using the anomalous signal from native sulfur atoms, leading to a bias-free room temperature structure of the human A2A adenosine receptor at 1.9 Å resolution. The advancement was made possible by recent improvements in SFX data analysis and the design of injectors and delivery media for streaming hydrated microcrystals. This general method should accelerate structural studies of novel difficult-to-crystallize macromolecules and their complexes. PMID:27679816

  15. The Turn-on of LCLS: the X-Ray Free Electron Laser at SLAC ( Keynote - 2011 JGI User Meeting)

    ScienceCinema

    Drell, Persis [SLAC Director

    2016-07-12

    The U.S. Department of Energy Joint Genome Institute (JGI) invited scientists interested in the application of genomics to bioenergy and environmental issues, as well as all current and prospective users and collaborators, to attend the annual DOE JGI Genomics of Energy & Environment Meeting held March 22-24, 2011 in Walnut Creek, Calif. The emphasis of this meeting was on the genomics of renewable energy strategies, carbon cycling, environmental gene discovery, and engineering of fuel-producing organisms. The meeting features presentations by leading scientists advancing these topics. SLAC National Laboratory Director Persis Drell gives a keynote talk on "The Turn-on of LCLS: the X-Ray Free-Electron Laser at SLAC" at the 6th Genomics of Energy & Environment Meeting on March 22, 2011

  16. Single-Shot Coherent Diffraction Imaging of Microbunched Relativistic Electron Beams for Free-Electron Laser Applications

    NASA Astrophysics Data System (ADS)

    Marinelli, A.; Dunning, M.; Weathersby, S.; Hemsing, E.; Xiang, D.; Andonian, G.; O'Shea, F.; Miao, Jianwei; Hast, C.; Rosenzweig, J. B.

    2013-03-01

    With the advent of coherent x rays provided by the x-ray free-electron laser (FEL), strong interest has been kindled in sophisticated diffraction imaging techniques. In this Letter, we exploit such techniques for the diagnosis of the density distribution of the intense electron beams typically utilized in an x-ray FEL itself. We have implemented this method by analyzing the far-field coherent transition radiation emitted by an inverse-FEL microbunched electron beam. This analysis utilizes an oversampling phase retrieval method on the transition radiation angular spectrum to reconstruct the transverse spatial distribution of the electron beam. This application of diffraction imaging represents a significant advance in electron beam physics, having critical applications to the diagnosis of high-brightness beams, as well as the collective microbunching instabilities afflicting these systems.

  17. Experimental Demonstration of Longitudinal Beam Phase-Space Linearizer in a Free-Electron Laser Facility by Corrugated Structures

    NASA Astrophysics Data System (ADS)

    Deng, Haixiao; Zhang, Meng; Feng, Chao; Zhang, Tong; Wang, Xingtao; Lan, Taihe; Feng, Lie; Zhang, Wenyan; Liu, Xiaoqing; Yao, Haifeng; Shen, Lei; Li, Bin; Zhang, Junqiang; Li, Xuan; Fang, Wencheng; Wang, Dan; Couprie, Marie-emmanuelle; Lin, Guoqiang; Liu, Bo; Gu, Qiang; Wang, Dong; Zhao, Zhentang

    2014-12-01

    Removal of the undesired time-energy correlations in the electron beam is of paramount importance for efficient lasing of a high-gain free-electron laser. Recently, it has been theoretically and experimentally demonstrated that the longitudinal wakefield excited by the electrons themselves in a corrugated structure allows for precise control of the electron beam phase space. In this Letter, we report the first utilization of a corrugated structure as a beam linearizer in the operation of a seeded free-electron laser driven by a 140 MeV linear accelerator, where a gain of ˜10 000 over spontaneous emission was achieved at the second harmonic of the 1047 nm seed laser, and a free-electron laser bandwidth narrowing by 50% was observed, in good agreement with the theoretical expectations.

  18. Development of an All Solid State 6 kHz Pulse Generator for Driving Free Electron Laser Amplifiers

    DTIC Science & Technology

    1990-07-16

    REPORT SRL-08-F-1990 SDEVELOPMENT OF AN ALL SOLID STATE 6 kHzIPULSE GENERATOR FOR DRIVING FREE 0ELECTRON LASER AMPLIFIERS Prepared byN NDr. Daniel...Clazification) Development of an All Solid State 6 kHz Pulse Generator for Driving Free Electron Laser Amplifiers 12. PERSONAL AUTHOR(S) Dr. Daniel Birx 13a...efficient, reliable pulsed power source to drive free electron laser amplifiers. Four of these have been constructed and tested. These SCR-commutated

  19. Imaging charge and energy transfer in molecules using free-electron lasers

    NASA Astrophysics Data System (ADS)

    Rudenko, Artem

    2014-05-01

    Charge and energy transfer reactions drive numerous important processes in physics, chemistry and biology, with applications ranging from X-ray astrophysics to artificial photosynthesis and molecular electronics. Experimentally, the central goal in studies of transfer phenomena is to trace the spatial localization of charge at a given time. Because of their element and site sensitivity, ultrafast X-rays provide a promising tool to address this goal. In this talk I will discuss several experiments where free-electron lasers were employed to study charge and energy transfer dynamics in fragmenting molecules. In a first example, we used intense, 70 femtosecond 1.5 keV pulses from the Linac Coherent Light Source (LCLS) to study distance dependence of electron transfer in laser-dissociated methyl iodide molecules. Inducing well-localized positive charge on the heavy iodine atom, we observe signature of electron transition from the separated methyl group up to the distances of 35 atomic units. In a complementary experiment, we studied charge exchange between two partners in a dissociating molecular iodine employing a pump-probe arrangement with two identical 90 eV pulses from the Free-Electron LASer in Hamburg (FLASH). In both cases, the effective spatial range of the electron transfer can be reasonably described by a classical over-the-barrier model developed for ion-atom collisions. Finally, I will discuss a time-resolved measurement on non-local relaxation mechanism based on a long-range energy transfer, the so-called interatomic Coulombic decay. This work was supported by Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, Office of Science, US Department of Energy and by the Kansas NSF ``First Award'' program.

  20. Pair production from vacuum at the focus of an X-ray free electron laser

    NASA Astrophysics Data System (ADS)

    Ringwald, A.

    2001-06-01

    There are definite plans for the construction of X-ray free electron lasers (FEL), both at DESY, where the so-called XFEL is part of the design of the electron-positron linear collider TESLA, as well as at SLAC, where the so-called Linac Coherent Light Source (LCLS) has been proposed. Such an X-ray laser would allow for high-field science applications: one could make use of not only the high energy and transverse coherence of the X-ray beam, but also of the possibility of focusing it to a spot with a small radius, hopefully in the range of the laser wavelength. Along this route one obtains very large electric fields, much larger than those obtainable with any optical laser of the same power. In this Letter we discuss the possibility of obtaining an electric field so high that electron-positron pairs are spontaneously produced in vacuum (Schwinger pair production). We find that if X-ray optics can be improved to approach the diffraction limit of focusing, and if the power of the planned X-ray FELs can be increased to the terawatt region, then there is ample room for an investigation of the Schwinger pair production mechanism.

  1. Circular dichroism measurements at an x-ray free-electron laser with polarization control

    SciTech Connect

    Hartmann, G.; Shevchuk, I.; Walter, P.; Viefhaus, J.; Lindahl, A. O.; Knie, A.; Hartmann, N.; Lutman, A. A.; MacArthur, J. P.; Glownia, J. M.; Helml, W.; Huang, Z.; Marinelli, A.; Nuhn, H.-D.; Moeller, S.; Coffee, R. N.; Ilchen, M.; Buck, J.; Galler, A.; Liu, J.; and others

    2016-08-15

    A non-destructive diagnostic method for the characterization of circularly polarized, ultraintense, short wavelength free-electron laser (FEL) light is presented. The recently installed Delta undulator at the LCLS (Linac Coherent Light Source) at SLAC National Accelerator Laboratory (USA) was used as showcase for this diagnostic scheme. By applying a combined two-color, multi-photon experiment with polarization control, the degree of circular polarization of the Delta undulator has been determined. Towards this goal, an oriented electronic state in the continuum was created by non-resonant ionization of the O{sub 2} 1s core shell with circularly polarized FEL pulses at hν ≃ 700 eV. An also circularly polarized, highly intense UV laser pulse with hν ≃ 3.1 eV was temporally and spatially overlapped, causing the photoelectrons to redistribute into so-called sidebands that are energetically separated by the photon energy of the UV laser. By determining the circular dichroism of these redistributed electrons using angle resolving electron spectroscopy and modeling the results with the strong-field approximation, this scheme allows to unambiguously determine the absolute degree of circular polarization of any pulsed, ultraintense XUV or X-ray laser source.

  2. Circular dichroism measurements at an x-ray free-electron laser with polarization control

    NASA Astrophysics Data System (ADS)

    Hartmann, G.; Lindahl, A. O.; Knie, A.; Hartmann, N.; Lutman, A. A.; MacArthur, J. P.; Shevchuk, I.; Buck, J.; Galler, A.; Glownia, J. M.; Helml, W.; Huang, Z.; Kabachnik, N. M.; Kazansky, A. K.; Liu, J.; Marinelli, A.; Mazza, T.; Nuhn, H.-D.; Walter, P.; Viefhaus, J.; Meyer, M.; Moeller, S.; Coffee, R. N.; Ilchen, M.

    2016-08-01

    A non-destructive diagnostic method for the characterization of circularly polarized, ultraintense, short wavelength free-electron laser (FEL) light is presented. The recently installed Delta undulator at the LCLS (Linac Coherent Light Source) at SLAC National Accelerator Laboratory (USA) was used as showcase for this diagnostic scheme. By applying a combined two-color, multi-photon experiment with polarization control, the degree of circular polarization of the Delta undulator has been determined. Towards this goal, an oriented electronic state in the continuum was created by non-resonant ionization of the O2 1s core shell with circularly polarized FEL pulses at hν ≃ 700 eV. An also circularly polarized, highly intense UV laser pulse with hν ≃ 3.1 eV was temporally and spatially overlapped, causing the photoelectrons to redistribute into so-called sidebands that are energetically separated by the photon energy of the UV laser. By determining the circular dichroism of these redistributed electrons using angle resolving electron spectroscopy and modeling the results with the strong-field approximation, this scheme allows to unambiguously determine the absolute degree of circular polarization of any pulsed, ultraintense XUV or X-ray laser source.

  3. Strong coupling operation of a free-electron-laser amplifier with an axial magnetic field

    NASA Astrophysics Data System (ADS)

    Rullier, J. L.; Devin, A.; Gardelle, J.; Labrouche, J.; Le Taillandier, P.; Donohue, J. T.

    1996-03-01

    We present the results of a free-electron-laser (FEL) experiment at 35 GHz, using a strongly relativistic electron beam (T=1.75 MeV). The electron pulse length is 30 ns full width at half maximum with a peak current of 400 A. The FEL is designed to operate in the high-gain Compton regime, with a negative coupling parameter (Φ<0) leading to a strong growth rate. More than 50 MW of rf power in the TE11 mode (43 dB gain) has been obtained with good reproducibility. The experimental results are in good agreement with predictions made using the three-dimensional stationary simulation code solitude.

  4. Potential application of the Los Alamos free-electron laser: High-temperature superconductors

    SciTech Connect

    Lumpkin, A.H.

    1988-01-01

    An improved understanding of High-Temperature Superconductors (HTSCs) should result from the direct investigation of the energy gap associated with the superconducting state. An adaptation of the classic transmission experiments using a broadly tunable Free- Electron Laser (FEL) to irradiate the HTSC single crystals or thin films as a function of photon energy and sample temperature is described. In particular, the Los Alamos FEL has a projected tuning range of 9-160..mu..m (140-8 MeV). In addition, its 10 to 20-ps micropulse structure, linear polarization, coherence, monochromaticity, focusability and peak power features should make it a unique research tool for probing HTSCs with critical temperature (T/sub c/) from /approximately/30 to /approximately/400 K (depending on the energy gaps involved). 14 refs., 4 figs., 2 tabs.

  5. Applications of free electron lasers and synchrotrons in industry and research

    SciTech Connect

    Barletta, William A.

    2013-04-19

    Synchrotron radiation sources have had a profound effect on both science and technology from their beginnings decades ago as parasitic operations on accelerators for high energy physics. Now the general area of photon science has opened up new experimental techniques which have become the mainstay tools of materials science, surface physics, protein crystallography, and nanotechnology. With the promise of ultra-bright beams from the latest generation of storage rings and free electron lasers with full coherence, the tools of photon science promise to open a new area of mesoscale science and technology as well as prove to be a disruptive wildcard in the search for sustainable energy technologies. This review will survey a range of applications and explore in greater depth the potential applications to EUV lithography and to technologies for solar energy.

  6. Using pipe with corrugated walls for a subterahertz free electron laser

    DOE PAGES

    Stupakov, Gennady

    2015-03-18

    A metallic pipe with corrugated walls supports propagation of a high-frequency mode that is in resonance with a relativistic beam propagating along the axis of the pipe. This mode can be excited by a beam whose length is a fraction of the wavelength. In this paper, we study another option of excitation of the resonant mode—via the mechanism of the free electron laser instability. This mechanism works if the bunch length is much longer than the wavelength of the radiation and, hence, does not require bunch compression. As a result, it provides an alternative to excitation by short bunches thatmore » can be realized with relatively low energy and low peak-current electron beams.« less

  7. Generation of large-bandwidth x-ray free-electron-laser pulses

    NASA Astrophysics Data System (ADS)

    Saa Hernandez, Angela; Prat, Eduard; Bettoni, Simona; Beutner, Bolko; Reiche, Sven

    2016-09-01

    X-ray free-electron lasers (XFELs) are modern research tools in disciplines such as biology, material science, chemistry, and physics. Besides the standard operation that aims at minimizing the bandwidth of the produced XFEL radiation, there is a strong scientific demand to produce large-bandwidth XFEL pulses for several applications such as nanocrystallography, stimulated Raman spectroscopy, and multiwavelength anomalous diffraction. We present a self-consistent method that maximizes the XFEL pulse bandwidth by systematically maximizing the energy chirp of the electron beam at the undulator entrance. This is achieved by optimizing the compression scheme and the electron distribution at the source in an iterative back-and-forward tracking. Start-to-end numerical simulations show that a relative bandwidth of 3.25% full-width can be achieved for the hard x-ray pulses in the SwissFEL case.

  8. Single-Molecule Imaging with X-Ray Free-Electron Lasers: Dream or Reality?

    SciTech Connect

    Fratalocchi, A.; Ruocco, G.

    2011-03-11

    X-ray free-electron lasers (XFEL) are revolutionary photon sources, whose ultrashort, brilliant pulses are expected to allow single-molecule diffraction experiments providing structural information on the atomic length scale of nonperiodic objects. This ultimate goal, however, is currently hampered by several challenging questions basically concerning sample damage, Coulomb explosion, and the role of nonlinearity. By employing an original ab initio approach, we address these issues showing that XFEL-based single-molecule imaging will be only possible with a few-hundred long attosecond pulses, due to significant radiation damage and the formation of preferred multisoliton clusters which reshape the overall electronic density of the molecular system at the femtosecond scale.

  9. Transverse emittance preservation during bunch compression in the Fermi free electron laser

    NASA Astrophysics Data System (ADS)

    di Mitri, S.; Allaria, E. M.; Craievich, P.; Fawley, W.; Giannessi, L.; Lutman, A.; Penco, G.; Spampinati, S.; Trovo, M.

    2012-02-01

    A characterization of the transverse emittance of a 200 pC, 6 ps long electron bunch has been performed in the Fermi@Elettra Free Electron Laser (FEL) first bunch compressor area. This region includes a magnetic bunch length compressor, diagnostics, and quadrupole magnets. The beam is time compressed in one stage, without linearization of the longitudinal phase space. Some growth of the normalized emittance has been measured in the compressor area. To understand this effect, we have investigated mechanisms of emittance growth such as coherent synchrotron radiation emission, chromatic aberration, and spurious dispersion. We show that careful optics control inside the compressor is essential for emittance growth reduction. The final configuration of one-stage magnetic compression limits the emittance to values below the design goal of 2 mm mrad, up to a compression factor of about 5. This machine configuration has been adopted to optimize FEL radiation output at wavelengths in the range 30-60 nm.

  10. A novel approach in the free-electron laser diagnosis based on a pixelated phosphor detector.

    PubMed

    Matruglio, Alessia; Dal Zilio, Simone; Sergo, Rudi; Mincigrucci, Riccardo; Svetina, Cristian; Principi, Emiliano; Mahne, Nicola; Raimondi, Lorenzo; Turchet, Alessio; Masciovecchio, Claudio; Lazzarino, Marco; Cautero, Giuseppe; Zangrando, Marco

    2016-01-01

    A new high-performance method for the free-electron laser (FEL) focused beam diagnosis has been successfully tested at the FERMI FEL in Trieste, Italy. The novel pixelated phosphor detector (PPD) consists of micrometric pixels produced by classical UV lithography and dry etching technique, fabricated on a silicon substrate, arranged in a hexagonal geometry and filled with suitable phosphors. It has been demonstrated that the overall resolution of the system has increased by reducing the diffusion of the light in the phosphors. Various types of PPD have been produced and tested, demonstrating a high resolution in the beam profile and the ability to measure the actual spot size shot-to-shot with an unprecedented resolution. For these reasons, the proposed detector could become a reference technique in the FEL diagnosis field.

  11. A single-shot transmissive spectrometer for hard x-ray free electron lasers

    NASA Astrophysics Data System (ADS)

    Zhu, Diling; Cammarata, Marco; Feldkamp, Jan M.; Fritz, David M.; Hastings, Jerome B.; Lee, Sooheyong; Lemke, Henrik T.; Robert, Aymeric; Turner, James L.; Feng, Yiping

    2012-07-01

    We report hard x-ray single-shot spectral measurements of the Linac Coherent Light Source. The spectrometer is based on a 10 μm thick cylindrically bent Si single crystal operating in the symmetric Bragg geometry to provide dispersion and high transmission simultaneously. It covers a spectral range >1% using the Si(111) reflection. Using the Si(333) reflection, it reaches a resolving power of better than 42 000 and transmits >83% of the incident flux at 8.3 keV. The high resolution enabled the observation of individual spectral spikes characteristic of a self-amplified spontaneous emission x-ray free electron laser source. Potential applications of the device are discussed.

  12. Ultrafast myoglobin structural dynamics observed with an X-ray free-electron laser

    DOE PAGES

    Levantino, Matteo; Schirò, Giorgio; Lemke, Henrik Till; ...

    2015-04-02

    Light absorption can trigger biologically relevant protein conformational changes. The light induced structural rearrangement at the level of a photoexcited chromophore is known to occur in the femtosecond timescale and is expected to propagate through the protein as a quake-like intramolecular motion. Here we report direct experimental evidence of such ‘proteinquake’ observed in myoglobin through femtosecond X-ray solution scattering measurements performed at the Linac Coherent Light Source X-ray free-electron laser. An ultrafast increase of myoglobin radius of gyration occurs within 1 picosecond and is followed by a delayed protein expansion. As the system approaches equilibrium it undergoes damped oscillations withmore » a ~3.6-picosecond time period. Our results unambiguously show how initially localized chemical changes can propagate at the level of the global protein conformation in the picosecond timescale.« less

  13. Study of the Coupling of Terahertz Radiation to Heterostructure Transistors with a Free Electron Laser Source

    NASA Astrophysics Data System (ADS)

    Ortolani, Michele; di Gaspare, Alessandra; Giovine, Ennio; Evangelisti, Florestano; Foglietti, Vittorio; Doria, Andrea; Gallerano, Gian Piero; Giovenale, Emilio; Messina, Giovanni; Spassovsky, Ivan; Lanzieri, Claudio; Peroni, Marco; Cetronio, Antonio

    2009-12-01

    High electron mobility transistors can work as room-temperature direct detectors of radiation at frequency much higher than their cutoff frequency. Here, we present a tool based on a Free Electron Laser source to study the detection mechanism and the coupling of the high frequency signal into the transistor channel. We performed a mapping over a wide area of the coupling of 0.15 THz radiation to an AlGaN/GaN transistors with cut-off frequency of 30 GHz. Local, polarization-dependent irradiation allowed us to selectively couple the signal to the channel either directly or through individual transistor bias lines, in order to study the nonlinear properties of the transistor channel. Our results indicate that HEMT technology can be used to design a millimeter-wave focal plane array with integrated planar antennas and readout electronics.

  14. Application of nonlinear models to estimate the gain of one-dimensional free-electron lasers

    NASA Astrophysics Data System (ADS)

    Peter, E.; Rizzato, F. B.; Endler, A.

    2017-06-01

    In the present work, we make use of simplified nonlinear models based on the compressibility factor (Peter et al., Phys. Plasmas, vol. 20 (12), 2013, 123104) to predict the gain of one-dimensional (1-D) free-electron lasers (FELs), considering space-charge and thermal effects. These models proved to be reasonable to estimate some aspects of 1-D FEL theory, such as the position of the onset of mixing, in the case of a initially cold electron beam, and the position of the breakdown of the laminar regime, in the case of an initially warm beam (Peter et al., Phys. Plasmas, vol. 21 (11), 2014, 113104). The results given by the models are compared to wave-particle simulations showing a reasonable agreement.

  15. Ultrafast myoglobin structural dynamics observed with an X-ray free-electron laser

    PubMed Central

    Levantino, Matteo; Schirò, Giorgio; Lemke, Henrik Till; Cottone, Grazia; Glownia, James Michael; Zhu, Diling; Chollet, Mathieu; Ihee, Hyotcherl; Cupane, Antonio; Cammarata, Marco

    2015-01-01

    Light absorption can trigger biologically relevant protein conformational changes. The light-induced structural rearrangement at the level of a photoexcited chromophore is known to occur in the femtosecond timescale and is expected to propagate through the protein as a quake-like intramolecular motion. Here we report direct experimental evidence of such ‘proteinquake’ observed in myoglobin through femtosecond X-ray solution scattering measurements performed at the Linac Coherent Light Source X-ray free-electron laser. An ultrafast increase of myoglobin radius of gyration occurs within 1 picosecond and is followed by a delayed protein expansion. As the system approaches equilibrium it undergoes damped oscillations with a ~3.6-picosecond time period. Our results unambiguously show how initially localized chemical changes can propagate at the level of the global protein conformation in the picosecond timescale. PMID:25832715

  16. Relativistic x-ray free-electron lasers in the quantum regime.

    PubMed

    Eliasson, Bengt; Shukla, P K

    2012-06-01

    We present a nonlinear theory for relativistic x-ray free-electron lasers in the quantum regime, using a collective Klein-Gordon (KG) equation (for relativistic electrons), which is coupled with the Maxwell-Poisson equations for the electromagnetic and electrostatic fields. In our model, an intense electromagnetic wave is used as a wiggler which interacts with a relativistic electron beam to produce coherent tunable radiation. The KG-Maxwell-Poisson model is used to derive a general nonlinear dispersion relation for parametric instabilities in three space dimensions, including an arbitrarily large amplitude electromagnetic wiggler field. The nonlinear dispersion relation reveals the importance of quantum recoil effects and oblique scattering of the radiation that can be tuned by varying the beam energy.

  17. Design of sub-Angstrom compact free-electron laser source

    NASA Astrophysics Data System (ADS)

    Bonifacio, Rodolfo; Fares, Hesham; Ferrario, Massimo; McNeil, Brian W. J.; Robb, Gordon, R. M.

    2017-01-01

    In this paper, we propose for first time practical parameters to construct a compact sub-Angstrom Free Electron Laser (FEL) based on Compton backscattering. Our recipe is based on using picocoulomb electron bunch, enabling very low emittance and ultracold electron beam. We assume the FEL is operating in a quantum regime of Self Amplified Spontaneous Emission (SASE). The fundamental quantum feature is a significantly narrower spectrum of the emitted radiation relative to classical SASE. The quantum regime of the SASE FEL is reached when the momentum spread of the electron beam is smaller than the photon recoil momentum. Following the formulae describing SASE FEL operation, realistic designs for quantum FEL experiments are proposed. We discuss the practical constraints that influence the experimental parameters. Numerical simulations of power spectra and intensities are presented and attractive radiation characteristics such as high flux, narrow linewidth, and short pulse structure are demonstrated.

  18. A Bragg beam splitter for hard x-ray free-electron lasers.

    PubMed

    Osaka, Taito; Yabashi, Makina; Sano, Yasuhisa; Tono, Kensuke; Inubushi, Yuichi; Sato, Takahiro; Matsuyama, Satoshi; Ishikawa, Tetsuya; Yamauchi, Kazuto

    2013-02-11

    We report a Bragg beam splitter developed for utilization of hard x-ray free-electron lasers. The splitter is based on an ultrathin silicon crystal operating in the symmetric Bragg geometry to provide high reflectivity and transmissivity simultaneously. We fabricated frame-shaped Si(511) and (110) crystals with thicknesses below 10 μm by a reactive dry etching method using atmospheric-pressure plasma. The thickness variation over an illuminated area is less than 300 nm peak-to-valley. High crystalline perfection was verified by topographic and diffractometric measurements. The crystal thickness was evaluated from the period of the Pendellösung beats measured with a highly monochromatic and collimated x-ray probe. The crystals provide two replica pulses with uniform wavefront [(<1/50)λ] and low spatial intensity variation (<5%). These Bragg beam splitters will play an important role in innovating XFEL applications.

  19. Single-shot beam-position monitor for x-ray free electron laser.

    PubMed

    Tono, Kensuke; Kudo, Togo; Yabashi, Makina; Tachibana, Takeshi; Feng, Yiping; Fritz, David; Hastings, Jerome; Ishikawa, Tetsuya

    2011-02-01

    We have developed an x-ray beam-position monitor for detecting the radiation properties of an x-ray free electron laser (FEL). It is composed of four PIN photodiodes that detect backscattered x-rays from a semitransparent diamond film placed in the beam path. The signal intensities from the photodiodes are used to compute the beam intensity and position. A proof-of-principle experiment at a synchrotron light source revealed that the error in the beam position is reduced to below 7 μm by using a nanocrystal diamond film prepared by plasma-enhanced chemical vapor deposition. Owing to high dose tolerance and transparency of the diamond film, the monitor is suitable for routine diagnostics of extremely intense x-ray pulses from the FEL.

  20. Ultrafast myoglobin structural dynamics observed with an X-ray free-electron laser

    SciTech Connect

    Levantino, Matteo; Schirò, Giorgio; Lemke, Henrik Till; Cottone, Grazia; Glownia, James Michael; Zhu, Diling; Chollet, Mathieu; Ihee, Hyotcherl; KAIST, Daejeon; Cupane, Antonio; Cammarata, Marco

    2015-04-02

    Light absorption can trigger biologically relevant protein conformational changes. The light induced structural rearrangement at the level of a photoexcited chromophore is known to occur in the femtosecond timescale and is expected to propagate through the protein as a quake-like intramolecular motion. Here we report direct experimental evidence of such ‘proteinquake’ observed in myoglobin through femtosecond X-ray solution scattering measurements performed at the Linac Coherent Light Source X-ray free-electron laser. An ultrafast increase of myoglobin radius of gyration occurs within 1 picosecond and is followed by a delayed protein expansion. As the system approaches equilibrium it undergoes damped oscillations with a ~3.6-picosecond time period. Our results unambiguously show how initially localized chemical changes can propagate at the level of the global protein conformation in the picosecond timescale.