We study the characteristics of the electron motion in this type of undulators and analyze the spectral properties of the emitted radiation. In freeelectron lasers stimulated emission comes from electrons passing through a magnetic field that periodically varies in direction and intensity, causing the electrons to accelerate and release light energy. Lasers, freeelectron 3 undulator electron beam optical cavity mirror partial mirror radiation field outcoupled field fig. Undulators and generation of xray pulses in freeelectron.
Free electron lasers operating with variably polarization. Sep 14, 2001 we discuss the use of tapered undulators to enhance the performance of free electron lasers fels based upon selfamplified spontaneous emission sase, where the radiation tends to have a relatively broad bandwidth, limited temporal phase coherence, and large amplitude fluctuations. This was first observed on a general electric synchrotron accelerator in 1947 and the light was called synchrotron radiation. Main fel schemes, useful for generation of high frequency radiation, extending to xrays, are presented.
The actual undulator pole gaps were assumed to be 0. Compton thomson scattering undulator source with micron period. Highquality electron beams from a helical inverse free. Charles brau, free electron lasers academic press, 1990, slightly outdated.
Sunday, august 20, 2017 santa fe community convention center sfccc foyer. Files are available under licenses specified on their description page. Introduction to free electron lasers and fourthgeneration. May 25, 2017 the results of theoretical examination and comparative analysis of synchrotron radiation sources specifically, undulators and xray free electron lasers fels are presented. Undulators for short pulse xray selfamplified spontaneous. Undulator options for soft xray free electron lasers. The development of laser wakefield accelerators lwfa over the past several years has led to an interest in very compact sources of xray radiation such as tabletop free electron lasers. Fel physics summary us particle accelerator school. Principles, properties and applications claudio pellegrini, ucla, and joachim stohr, ssrl 1. The physics of free electron lasers by saldin, schneidmiller and yurkov and to the lectures by j. A short introduction to free electron lasers the cern accelerator. The advantages and disadvantages of single pass and of multipass designs are.
The free electron laser is tunable and has the widest frequency range of any laser type, 3 currently ranging in wavelength from microwaves, through terahertz. Rossbach at the cern accelerator school on synchrotron radiation. Inverse compton scattering ics source scatter a laser off a relativistic electron beam two views. However, the use of conventional undulators using permanent magnets also implies system sizes which are large. The electrons are bound to atomic, molecular or solidstate levels, so one may call this a. Laur 0901205 12 us particle acceus particle accelerator school 2009lerator school 2009 university of new mexico albuquerque nm course content 1. Pdf introduction to the physics of free electron laser and.
The freeelectron laser fel principle has been known since the early 1970s but for many years. Introduction flash began operation for experiments in the extended ultraviolet xuv and soft xray regime in summer 2005 as the worlds. We discuss the properties of free electron lasers fel operating with variably polarizing undulators. Special measurement and tuning techniques were used to satisfy the tight. Free electron lasers free electron lasers fels are sources of synchrotron radiation that can produce radiation with peak power and brightness orders of magnitude larger than the radiation produced by conventional sources such as dipoles and wigglers. Laser wave undulators and high gain xray free electron lasers. Thz emission from undulators and freeelectron lasers. Short period lengths and small gaps require an accurate correlation between hall probe position orientation and the 3dmagnetic field. Characteristics very similar to undulator radiation with k free electron laser fel is a kind of laser whose lasing medium consists of veryhighspeed electrons moving freely through a magnetic structure, hence the term free electron.
These tubes are still successful and useful sources of coherent radiation with wavelengths ranging from. Using the polychromatic fel simulation code ginger, we numerically demonstrate the effectiveness of a tapered. Ivanyushenkov, short period undulators for storage rings and free electron lasers, journal of physics. The paper presents a theoretical study of the harmonic power evolution in a singlepass freeelectron laser fel and a comparison with some. The linear accelerator linac is on the far left and is the largest linac in the world. The undulator shown is a permanentmagnet planar undulator. The magnetic structures are standard aps undulatory, 2. Since the electron beam acts as the gain medium in an fel, the pulse format of the. The results of theoretical examination and comparative analysis of synchrotron radiation sources specifically, undulators and xray freeelectron lasers fels are presented. Apr 24, 2015 among the different possible gain media, the free electron lasers fel uses free electrons in the period permanent magnetic field of an undulator, covering wavelengths from far infra red to xray. Free electron lasers fels are sources of synchrotron radiation that can produce radiation with peak power and brightness orders of magnitude larger than the radiation produced by conventional sources such as dipoles and wigglers. Highbrightness xray freeelectron laser with an optical. Introduction to free electron lasers and fourthgeneration light. Other articles where free electron laser is discussed.
Ixs opportunities offered by high repetition rate x ray. Studies of classical radiation emission from plasma wave. The freeelectron laser is tunable and has the widest frequency range of any laser type, currently ranging in wavelength from microwaves, through terahertz radiation and infrared, to the visible spectrum, ultraviolet. Mar 18, 20 comparison of the magnetic field in the undulator midplane for in vacuum smco undulators b eff and nbti superconducting undulators b 0 versus undulator period length for three beam stay clear gaps. Two insertion device magnetic structures have been prepared for the advanced photon source aps fel project 1.
Series cern accelerator school cern yellow reports. Free electron laser fel theory is extended to explain several effects associated with. The undulators tuning the fel is achieved by varying the undulator gap and by changing the electron beam energy between 750950mev. Threedimensional, timedependent simulation of freeelectron. Birds eye view of slac, where the highlighted region in the diagram is lcls. We also derive general expressions for the small signal gain coefficient and for the saturation intensity. The first sources of powerful coherent radiation were the microwave tubes invented earlier in this century. Plasma wave undulator geometry, showing propagation directions of the excitation lasers, electron beam, plasma wave, and radiation. Using the polychromatic fel simulation code ginger, we numerically demonstrate the effectiveness of a. Superconducting undulators from an idea to real devices. Block 2 capabilities depend on technical improvements to fiber lasers of blocks 1 and 1a to achieve better beam quality and greater output power with improved beam control to buy greater power delivered to targets at increased range. Free electron lasers are laser devices where light amplification occurs by interaction with fast electrons in an undulator. Zagorodnova adeutsches elektronen synchrotron, notkestrasse 85, 22607 hamburg, germany beuropean xfel gmbh, holzkoppel 4, 22869 schenefeld, germany cnrc kurchatov institute, akademika kurchatova pl.
The particles are distributed over several compute nodes which comminicate using openmpi. In later developments, stemming from this, single pass gain of circularly polarized radiation was experimentally demonstrated by means of a twister structure and an optical cavity, obtained by adding mirrors to the magnet assembly, was used to achieve buildup of the radiation in an oscillator device known as the freeelectron laser. Slac beambased alignment of undulators for freeelectron lasers thursday, august 24, 2017 sfccc, lanl, bradbury science museum, eldorado hotel. In free electron lasers stimulated emission comes from electrons passing through a magnetic field that periodically varies in direction and intensity, causing the electrons to accelerate and release light energy. Hallprobe bench for cryogenic invacuumundulators inspire. For the planar undulators above a period of 45mm was chosen to enable tuning over the photon energy range 10100ev. Manhan3, georg wittig 2, bernhard hidding,3, brian w. Jefferson labs freeelectron laser is the worlds highestpower tunable infrared laser and was developed using the labs expertise in superconducting radiofrequency srf accelerators. The values of the physical parameters which can be obtained by using a ndglass laser undulators are provided in fig.
Colson w b 1990 classical free electron laser theory laser handbook vol 6, ed w b colson et al. We discuss the use of tapered undulators to enhance the performance of freeelectron lasers fels based upon selfamplified spontaneous emission sase, where the radiation tends to have a relatively broad bandwidth, limited temporal phase coherence, and large amplitude fluctuations. This new reference is the first fully selfcontained and unified monograph on the design and operation of undulators and freeelectron lasers. Tapered undulator for sase fels unt digital library. Ixs opportunities offered by high repetition rate x ray free. Measurements and tuning of the undulatory have been completed at a magnetic gap of about 9. Particle accelerator school august 112, 1988 are presented. Schlueter lawrence berkeley national laboratory, berkeley, ca, usa abstract soft xray free electron laser sources require signi. It will be of use to all those working in freeelectron laser research as well as for physicists and graduate students who need an introduction to the field. Electron injectors chapter chapter chapter chapter chapter chapter chapter. Their development received a strong impetus from radar development during world war ii. Schmuser, et al ultraviolet and soft xray freeelectron lasers, springer, 2008 conventional boundelectron laser radiation is generated by stimulated emission main components.
Comparison of the magnetic field in the undulator midplane for in vacuum smco undulators b eff and nbti superconducting undulators b 0 versus undulator period length for three beam stay clear gaps. Harmonic generation in planar undulators in singlepass free. Among the different possible gain media, the free electron lasers fel uses free electrons in the period permanent magnetic field of an undulator, covering wavelengths from far. A freeelectron laser fel is a kind of laser whose lasing medium consists of veryhighspeed electrons moving freely through a magnetic structure, hence the term free electron. When fast electrons at nearly the speed of light cross a magnetic field on their way, they are deflected and generate bright, well collimated light tangentially to their curved path. Short period lengths and small gaps require an accurate correlation between hall. Comparison of conventional laser and free electron laser p.
Media in category free electron lasers the following 11 files are in this category, out of 11 total. In fact fel is based on the stimulated emission of virtual photons by a relativistic electron beam, passing through an undulatorwiggler, much like conventional. Magnetic measurements and tuning of undulators for the aps. Fel 2017 conference booklet pdf prerelease of fel 2017 proceedings portable acrobat format pdf files of the oral presentations and papers that have been processed. Us navy plans for scaling free electron lasers to megawatt. Other articles where freeelectron laser is discussed. Because the electrons do not transition between welldefined energy levels, some specialists question. Free electron lasers produced by the resonant interaction of a relativistic electron beam with a photon beam in an undulator tunable, powerful, coherent radiation sources 1977 first operation of a freeelectron laser at stanford university today 22 freeelectron lasers operating worldwide 19 fels proposed or in construction. Different electrons radiate independently in bending magnets as well as in undulators, hence the total power produced by a bunch of n electrons is simply n times the radiation power of one electron. It can have the optical properties characteristic of conventional lasers such as high spatial coherence and a near diffraction limited radiation beam.
The fel also provides ultraviolet laser light, including vacuum ultraviolet light, and is also a source of terahertz light. The synchrotron radiation of relativistic electrons in undulator magnets and the lowgain freeelectron laser fel are discussed in some detail. Pelligrini, introduction to the physics of the free electron laser, laser handbook, vol. Successful freeelectron based light sources can be developed along the the lines described by einstein, schawlow and townes based solely on transition rates the con. The experimental hutches are the rooms to the far right of the image. Introduction creating matter from the vacuum, taking an atomic scale motion picture of a chemical process in a time of a few femtoseconds 1 fs 1015 sec or unraveling the complex.
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