[show abstract][hide abstract] ABSTRACT: This report describes the scientific aims and potentials as well as the
preliminary technical design of IRIDE, an innovative tool for
multi-disciplinary investigations in a wide field of scientific, technological
and industrial applications. IRIDE will be a high intensity 'particle factory',
based on a combination of a high duty cycle radio-frequency superconducting
electron linac and of high energy lasers. Conceived to provide unique research
possibilities for particle physics, for condensed matter physics, chemistry and
material science, for structural biology and industrial applications, IRIDE
will open completely new research possibilities and advance our knowledge in
many branches of science and technology. IRIDE will contribute to open new
avenues of discoveries and to address most important riddles: What does matter
consist of? What is the structure of proteins that have a fundamental role in
life processes? What can we learn from protein structure to improve the
treatment of diseases and to design more efficient drugs? But also how does an
electronic chip behave under the effect of radiations? How can the heat flow in
a large heat exchanger be optimized? The scientific potential of IRIDE is far
reaching and justifies the construction of such a large facility in Italy in
synergy with the national research institutes and companies and in the
framework of the European and international research. It will impact also on
R&D work for ILC, FEL, and will be complementarity to other large scale
accelerator projects. IRIDE is also intended to be realized in subsequent
stages of development depending on the assigned priorities.
[show abstract][hide abstract] ABSTRACT: Free-electron lasers (FELs) are promising devices for generating light with laser-like properties in the extreme ultraviolet and X-ray spectral regions. Recently, FELs based on the self-amplified spontaneous emission (SASE) mechanism have allowed major breakthroughs in diffraction and spectroscopy applications, despite the relatively large shot-to-shot intensity and photon-energy fluctuations and the limited longitudinal coherence inherent in the SASE mechanism. Here, we report results on the initial performance of the FERMI seeded FEL, based on the high-gain harmonic generation configuration, in which an external laser is used to initiate the emission process. Emission from the FERMI FEL-1 source occurs in the form of pulses carrying energy of several tens of microjoules per pulse and tunable throughout the 65 to 20nm wavelength range, with unprecedented shot-to-shot wavelength stability, low-intensity fluctuations, close to transform-limited bandwidth, transverse and longitudinal coherence and full control of polarisation.
[show abstract][hide abstract] ABSTRACT: Measurements have recently been collected from the FERMI@elettra Free Electron Laser first bunch compressor area. This region includes a magnetic compressor, diagnostics for the characterization of the longitudinal and transverse phase space and suitable optics for matching to the downstream part of the linac. We report on the beam dynamics investigations in comparison with the modeling as well as the high level software control that was essential in making these measurements.
32nd International Free Electron Laser Conference; 08/2010
[show abstract][hide abstract] ABSTRACT: The FERMI@Elettra injector, comprised of a high-gradient s-band photo-cathode RF gun, the Photocathode gun driven laser, the first two accelerating sections, the con-trols and the suite of diagnostics has been commissioned in 2009. In early 2010 linac commissioning up to 250MeV continued. The electron beam has been characterized in terms of charge, energy, energy spread and transverse emit-tance. In this paper we give an overview of the obtained results.
1st International Particle Accelerator Conference (IPAC'10); 05/2010
[show abstract][hide abstract] ABSTRACT: The aim of this paper is to investigate the effect of the magnetic bunch length compression on the development of the microbunching instability. It will be shown that, after removing the linear energy chirp required for the compression, an additional and properly tuned R56 transport matrix element is able to dilute the initial energy modulation and to suppress the current spikes created by the microbunching instability without affecting the bunch length. A by-product of the study is the observation that a single compressor is more effective than the two-compressors scheme in reducing the unwanted modulations caused by the microbunching instability. The study is based on analytical calculations and on the simulation code elegant.
Physical Review Special Topics - Accelerators and Beams 01/2010; 13(1). · 1.57 Impact Factor
[show abstract][hide abstract] ABSTRACT: FERMI@elettra is a fourth-generation light source user facility under construction at the Elettra Laboratory in Trieste, Italy. The high-quality 1.2 GeV electron beam drives two-seeded Free Electron Lasers (FELs) in the wavelength range 100−10 nm. Wavelength tunability, variable polarization and higher electron beam energies to reach even shorter output wavelengths are also in the machine delivery plan. This paper describes the physics processes that have been modelled to simulate FERMI@elettra and the computer codes used to optimize the machine design. The paper focuses on several design challenges and how these translate into modelling and simulation challenges.
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 09/2009; 608(1):19-27. · 1.14 Impact Factor
[show abstract][hide abstract] ABSTRACT: The new FERMI@Elettra photoinjector is presently un-dergoing high-power testing and characterization at MAX-lab in Lund, Sweden. This effort is a collaboration between Sincrotrone Trieste, MAX-lab and UCLA. The 1.6-cell RF gun cavity and the focusing solenoid were successfully de-signed and built by the Particle Beam Physics Laboratory at UCLA, delivered to Sincrotrone Trieste at the beginning of 2008, and installed in the linac tunnel at MAX-lab. Use of the MAX-lab facility will allow the FERMI project to progress significantly with the photoinjector while waiting for the completion of the new linac building extension at Sincrotrone Trieste. We report here on the high-power con-ditioning of the RF cavity and the first beam tests.
11th European Particle Accelerator Conference (EPAC 08), Genoa, Italy; 05/2008
[show abstract][hide abstract] ABSTRACT: Although terahertz (THz) radiation was first observed about 100 years ago, this portion of the electromagnetic spectrum at the boundary between the microwaves and the infrared has been, for a long time, rather poorly explored. This situation changed with the rapid development of coherent THz sources such as solid-state oscillators, quantum cascade lasers, optically pumped solid-state devices, and novel coherent radiator devices. These in turn have stimulated a wide variety of applications from material science to telecommunications, from biology to biomedicine. Recently, there have been two related compact coherent radiation devices invented able to produce up to megawatts of peak THz power by inducing a ballistic bunching effect on the electron beam, forcing the beam to radiate coherently. An introduction to the two systems and the corresponding output photon beam characteristics will be provided.
Proceedings of the IEEE 09/2007; · 6.91 Impact Factor
[show abstract][hide abstract] ABSTRACT: Computer simulations using a continuous change in particle energy are an important tool in improving the performance at the final stage of the Linac Coherent Light Source (LCLS) undulator line. Changes in the particle energy cause the break length between undulator segments to no longer be optimized. Radiation losses less than 0.1%/undulator segment can be easily compensated by adjustment of an undulator deflection parameter K. For higher losses, up to 0.4%, adjustment of K can still be compensated, but careful optimization is required. Compensating for losses greater than 0.4% requires tapering of the field within the undulator segment. The LCLS undulator segments are in mass production at this time. The first two undulators for the LCLS project were delivered to the APS magnetic measurement facility. They have already been tuned, and meet all requirements for the LCLS free-electron laser (FEL). The final results of this tuning will be presented, with emphasis on the FEL-specific requirements. A systematic zero shift in the Sentron [〈http://www.sentron.ch/〉. ] 2-axis Hall probe was discovered, which required correction in order to obtain the proper field integrals.
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 05/2007; 575:22-28. · 1.14 Impact Factor
[show abstract][hide abstract] ABSTRACT: Chemical analyses of U.S. stockpiled mustard chemical warfare agent show some agent destined for destruction contains mercury [L. Ember, Chem. Eng. News 82 (2004) 8]. Because of its toxicity, mercury must be removed from agent prior to incineration or be scrubbed from incineration exhaust to prevent release into the atmosphere. Understanding mercury/agent interactions is critical if either atmospheric or aqueous treatment processes are used. We investigate and compare the state of mercury in water to that in thiodiglycol, a mustard simulant, as co-contaminants are introduced. The effects of sodium hypochlorite and sodium hydroxide, common neutralization chemicals, on mercury in water and simulant with and without co-contaminants present are examined using X-ray absorption fine spectroscopy (XAFS).
[show abstract][hide abstract] ABSTRACT: There is growing interest within the user community to utilize the pulsed nature of synchrotron radiation from storage ring sources. Conventional third-generation light sources can provide pulses on the order of 100 ps but typically cannot provide pulses of about 1 ps that some users now require to advance their research programs. However, it was recently proposed by A. Zholents et al. to use rf orbit deflection to generate sub-ps x-ray pulses . In this scheme, two crab cavities are used to deliver a longitudinally dependent vertical kick to the beam, thus exciting longitudinally correlated vertical motion of the electrons. This makes it possible to spatially separate the radiation coming from different longitudinal parts of the beam. An optical slit can then be used to slice out a short part of the radiation pulse, or an asymmetrically cut crystal can be used to compress the radiation in time. In this paper we present a feasibility study of this method applied to the Advanced Photon Source (APS). We find that the pulse length can be decreased down to a 1 ps range using superconducting crab cavities.
Particle Accelerator Conference, 2005. PAC 2005. Proceedings of the; 06/2005
[show abstract][hide abstract] ABSTRACT: The generation ofharmonics through a nonlinear mechanis driven by bunching at the fundamentalhas ssdam interes as a path toward enhancing and extending the uspOzOFTH of an X-ray free-electronlase (FEL) facility. The seTLkk-zTH of the nonlinear harmonic generation to undulatorimperfections electron beam energy sergyT peak current, and emittanceis important in an evaluation of theprocesW Typically, linear insrTDDzJLTH inFELs are characterized by increasp sreaspTHp to both electron beam and undulator quality withincreas-T harmonic number. However,swev the nonlinear harmonic generationmechanis is driven by the growth of the fundamental, thesTDkLJFTHp of the nonlinear harmonic mechanis is not expected to besp-OF-THpJO greater than that of the fundamental. Inthis paper, wesTLW the effects of electron beam quality, moreseTJkzFpTHp emittance, energy sergyT and peak current, on the nonlinear harmonics in a 1.5- A FEL, and sdT that the decline in the harmonic emisnic roughlyfollows that of the fundamental.
[show abstract][hide abstract] ABSTRACT: The generation of harmonics through a nonlinear mechanism driven by bunching at the fundamental has sparked interest in using this process as a path toward an X-ray free-electron laser (FEL). An important issue in this regard is the sensitivity of the nonlinear harmonic generation to wiggler imperfections. Typically, linear instabilities in FELs are characterized by increasing sensitivity to both electron beam and wiggler quality with increasing harmonic number. However, since the nonlinear harmonic generation mechanism is driven by the growth of the fundamental, the sensitivity of the nonlinear harmonic mechanism is not severely greater than that of the fundamental. In this paper, we study the effects of wiggler imperfections on the nonlinear harmonics in a 1.5- FEL, and show that the decline in the third harmonic emission with increasing levels of wiggler imperfections roughly tracks that of the fundamental.
[show abstract][hide abstract] ABSTRACT: At the point of saturation in a high-gain free-electron laser (FEL) the light is fully transversely coherent. The number and evolution of the transverse modes is important for the effective tune-up and subsequent operation of FELs based on the photon beam characterization and in designing multi-module devices that rely on relatively stable saturation distances in each module. In the latter, this is particularly critical since each section will seed another module. Overall, in a single- or multi-module device, experimental users will desire stability in power and in photon beam quality. Using a numerical simulation code, the evolution of the transverse modes in the high-gain free-electron laser (FEL) is examined and is discussed. In addition, the transverse modes in the first few higher nonlinear harmonics are investigated.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 01/2004;
[show abstract][hide abstract] ABSTRACT: A new time-of-flight (TOF) mass spectrometer incorporating post-ionization of sputtered neutral species with tunable vacuum ultraviolet (VUV) light generated by a free electron laser (FEL) has been developed. Capabilities of this instrument, called SPIRIT, were demonstrated by experiments with photoionization of sputtered neutral gold atoms with 125 nm light generated by the VUV FEL located at Argonne National Laboratory (ANL). In a separate series of experiments with a fixed wavelength VUV light source, a 157 nm F2 laser, a useful yield (atoms detected per atoms sputtered) of about 12% and a mass resolution better than 1500 were demonstrated for molybdenum.
[show abstract][hide abstract] ABSTRACT: The self-amplified spontaneous emission free-electron laser experiments at the Advanced Photon Source are now operating in the VUV at 157nm for a user experiment. In conjunction with these runs, we have obtained the first coherent optical transition radiation data due to the microbunching of the electron beam in the VUV. We have used both near- and far-field focusing by selecting the spherical mirror with the appropriate focal length for the distance to the CCD chip. The optics are such that much higher resolution than our visible system is attained with calibration factors of 11μm/pixel and 10μrad/pixel, respectively. Localized effects in the distributions in both focal conditions are being addressed.
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment - NUCL INSTRUM METH PHYS RES A. 01/2004; 528(1):194-198.
[show abstract][hide abstract] ABSTRACT: Overlap of the particle and the photon beams in a self-amplified spontaneous emission (SASE) free-electron laser (FEL) is one of the keys to optimizing gain. We have now directly demonstrated an on-line method for gain improvement at 540 nm on the Advanced Photon Source FEL. This was achieved by steering the e-beam with correctors before an undulator based on the fringe symmetry in coherent optical transition radiation interference (COTRI) images observed after that undulator. For these conditions we determined that both the SASE and COTR image intensities were improved by about a factor of three in one 2.4-m-long undulator section. The initial tuning had been based on RF beam position monitor readings and the maximization of SASE image intensity in the cameras.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 01/2004;
[show abstract][hide abstract] ABSTRACT: We discuss the design elements of a compact free electron laser device, operating, in an oscillator–amplifier configuration, up to the soft X-ray region. We show that, the source can provide radiation from extreme UV to soft X-ray region, with significantly large output peak and average laser power with undulator lengths not exceeding 7 m.
[show abstract][hide abstract] ABSTRACT: We report on a characterization of the chaotic optical field from a high-gain, self-amplified spontaneous-emission (SASE) free-electron laser. The temporal structure of the amplitude and phase are measured in a single-shot mode, with a resolution well below the coherence length, and the statistics over multiple pulses is determined. The measurement is in excellent quantitative agreement with the prediction based on analysis of random noise, and further verifies the chaotic nature of the SASE optical field.
[show abstract][hide abstract] ABSTRACT: We report on the first measurements of the dependence on the axial distance z of the spectrum of self-amplified spontaneous emission free-electron laser (SASE FEL) radiation. The measurements are performed under different FEL conditions in the wavelength range from 265 to 530 nm. Spectral measurements of the radiation at FEL saturation are included. The z-dependence of the radiation spectrum is compared with theory and simulations.
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 07/2003; · 1.14 Impact Factor