P. Musumeci

University of California, Los Angeles, Los Ángeles, California, United States

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Publications (181)315.79 Total impact

  • D.B. Cesar · P. Musumeci · D. Alesini
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    ABSTRACT: In this paper we discuss a relative time-of-arrival measurement scheme between an electron beam and a mid-infrared laser pulse based on the electron-beam controlled transmission in semiconductor materials. This technique can be used as a time-stamping diagnostic in ultrafast electron diffraction or microscopy. In particular, our characterization of Germanium demonstrates that sub-ps time-of-arrival sensitivity could be achieved in a single shot and with very low charge beams (<1 pC). Detailed measurements as a function of the beam charge and the laser wavelength offer insights on the free carrier dynamics in the semiconductor upon excitation by the electron beam.
    No preview · Article · Dec 2015 · Journal of Applied Physics
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    J C H Spence · G Subramanian · P Musumeci
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    ABSTRACT: We consider the possibility of imaging individual bioparticles using snapshot diffraction from femotsecond pulses, using a 3 MeV electron beam, based on the recent experimental performance of these coherent beams. Assuming that radiation damage can be outrun using 100 fs pulses (or less), we find that a sufficient number of electrons are scattered per particle only if the beam diameter can be matched to that of the particle (e.g. a virus), about three orders of magnitude smaller than has currently been demonstrated (and limited by space-charge effects). We then propose the use of the hollow-cone illumination mode for fast transmission electron microscope imaging, because it can provide full-field atomic resolution imaging despite the use of the large incoherent annular source required for an efficient photocathode, so that coherent illumination is not needed for high-resolution imaging. Reciprocity arguments are used to compare this full-field mode with data aquisition times and source brightness in scanning transmission electron microscopy.
    Preview · Article · Nov 2015 · Journal of Physics B Atomic Molecular and Optical Physics
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    ABSTRACT: High gradient rf photoguns have been a key development to enable several applications of high quality electron beams. They allow the generation of beams with very high peak current and low transverse emittance, satisfying the tight demands for free-electron lasers, energy recovery linacs, Compton/Thomson sources and high-energy linear colliders. In the present paper we present the design of a new rf photogun recently developed in the framework of the SPARC_LAB photoinjector activities at the laboratories of the National Institute of Nuclear Physics in Frascati (LNF-INFN, Italy). This design implements several new features from the electromagnetic point of view and, more important, a novel technology for its realization that does not involve any brazing process. From the electromagnetic point of view the gun presents high mode separation, low peak surface electric field at the iris and minimized pulsed heating on the coupler. For the realization, we have implemented a novel fabrication design that, avoiding brazing, strongly reduces the cost, the realization time and the risk of failure. Details on the electromagnetic design, low power rf measurements and high power radiofrequency and beam tests performed at the University of California in Los Angeles (UCLA) are discussed in the paper.
    No preview · Article · Sep 2015 · Physical Review Special Topics - Accelerators and Beams
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    Full-text · Dataset · Jun 2015
  • X. H. Lu · C. X. Tang · R. K. Li · H. To · G. Andonian · P. Musumeci
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    ABSTRACT: In this paper, we discuss the velocity compression in a short rf linac of an electron bunch from a rf photoinjector operated in the blowout regime. Particle tracking simulations shows that with a beam charge of 2 pC an ultrashort bunch duration of 16 fs can be obtained at a tight longitudinal focus downstream of the linac. A simplified coherent transition radiation (CTR) spectrum method is developed to enable the measurement of ultrashort (sub-50 fs) bunches at low bunch energy (5 MeV) and low bunch charges (<10 pC). In this method, the ratio of the radiation energy selected by two narrow bandwidth filters is used to estimate the bunch length. The contribution to the coherent form factor of the large transverse size of the bunch suppresses the radiation signal significantly and is included in the analysis. The experiment was performed at the UCLA Pegasus photoinjector laboratory. The measurement results show bunches of sub-40 fs with 2 pC of charge well consistent with the simulation using actual experimental conditions. These results open the way to the generation of ultrashort bunches with time-duration below 10 fs once some of the limitations of the setup (rf phase jitter, amplitude instability and low field in the gun limited by breakdown) are corrected.
    No preview · Article · Mar 2015 · Physical Review Special Topics - Accelerators and Beams
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    ABSTRACT: Recent advancements in microelectromechanical system (MEMS) fabrication techniques have enabled the batch-fabrication of quadrupole MEMS electromagnets producing 100 mT-scale field across sub-mm gaps with the potential for transformational advances in the field of compact high performance charged particle focusing and steering optics. The footprint of these in-vacuum focusing and steering optics can be as small as 3 mm × 3 mm × 0.5 mm. The low electromagnet impedance (58 mΩ, 32 nH per pole) facilitates power-efficient operation and continuous or low duty cycle operation, and the individually controlled electromagnets allow combined dipole-quadrupole fields. Here we report on an experiment where these miniature devices have been used to focus and steer a 34 keV electron beam from a DC photogun, demonstrating the first application of magnetic MEMS to particle beam focusing.
    Full-text · Article · Feb 2015 · Physical Review Special Topics - Accelerators and Beams
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    ABSTRACT: Plasma acceleration is the new frontier in particle beam accelerators. Using the strong electric fields inside a plasma it is possible to achieve accelerating gradients orders of magnitude larger with respect to current technologies. Different schemes, using completely different approaches, have been proposed and several already tested, producing beams of energy up to several GeV. Regardless of the technique used for acceleration a precise determination of the output beam parameters is mandatory for the fine tuning of the process. The measurement of these parameters, in particular the beam distribution in transverse and longitudinal phase space, is not trivial, mainly due to the large energy spread and to the tight focusing of these beams or to the background noise produced in the plasma channel. We illustrate the main problems related to the diagnostic of this kind of beams and some of the proposed or already realized solutions
    Full-text · Article · Dec 2014 · Physics Procedia
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    ABSTRACT: UCLA/INFN-LNF/Univ. Rome has been developing the hybrid gun which has an RF gun and a short linac for velocity bunching in one structure. After the cavity was manufactured at INFN-LNF in 2012, tests of the gun was carried out at UCLA. The field in the standing wave part was 20% smaller than the simulation but the phase advance was fine. The cavity was commissioned successfully up to 13 MW. The beam test was performed at 11.5 MW and demonstrated the bunch compression.
    No preview · Conference Paper · Dec 2014
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    ABSTRACT: We discuss a new method for the production of trains of FEL radiation pulses based on the FEL emission driven by a comb-like electron beam. In addition, we present recent experimental results on the two color FEL emission as generated at the SPARC_LAB facility: a train of two short (<200 fs) electron bunches, almost overlapped in time, with a comb-like energy distribution, has been injected in the undulator, giving rise to FEL pulses at two characteristic frequencies with multi-peaked time structure. This scheme shows also the versatility of the SPARC photo-injector to generate and manipulate such energy and time distributions.
    Full-text · Article · Dec 2014 · Physics procedia
  • Nicholas Sudar · Pietro Musumeci · Joe Duris
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    ABSTRACT: 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.
    No preview · Article · Dec 2014 · Journal of Physics B Atomic Molecular and Optical Physics
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    ABSTRACT: We have developed, at the SPARC test facility, a procedure for a real time self-amplified spontaneous emission free electron laser (FEL) device performance control. We describe an actual FEL, including electron and optical beam transport, through a set of analytical formulas, allowing a fast and reliable on-line “simulation” of the experiment. The system is designed in such a way that the characteristics of the transport elements and the laser intensity are measured and adjusted, via a real time computation, during the experimental run, to obtain an on-line feedback of the laser performances. The detail of the procedure and the relevant experimental results are discussed.
    Full-text · Article · Nov 2014 · Physical Review Special Topics - Accelerators and Beams
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    Joseph Duris · Alex Murokh · Pietro Musumeci
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    ABSTRACT: High conversion efficiency between electrical and optical power is highly desirable both for high peak and high average power radiation sources. In this paper we discuss a new mechanism based on stimulated superradiant emission in a strongly tapered undulator whereby an optimal undulator tapering is calculated by dynamically matching the resonant energy variation to the ponderomotive decelerating gradient. The method has the potential to allow the extraction of a large fraction (~50%) of power from a relativistic electron beam and convert it into coherent narrow-band tunable radiation, and shows a clear path to very high average power radiation sources.
    Preview · Article · Oct 2014 · New Journal of Physics
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    ABSTRACT: 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.
    No preview · Article · Sep 2014 · Nature Communications
  • P. Musumeci · R. K. Li
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    ABSTRACT: In this paper we review the present status of MeV electron sources for ultrafast diffraction and microscopy applications and trace the path forward to improve the spatio-temporal resolution of electron scattering probes.
    No preview · Conference Paper · Sep 2014
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    L. Piazza · P. Musumeci · O.J. Luiten · Fabrizio Carbone
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    ABSTRACT: Recent advances in ultrafast technology enable both the study and the control of materials properties thanks to the ability to record high temporal resolution movies of their transformations, or the ability to generate new states of matter by selecting ad hoc an excitation to drive the system out of equilibrium. The holy grail of this type of experiments is to combine a high tuneability of the excitation with a wide observation window. For example, this is achieved in multidimensional optical spectroscopy where the response to several excitation energies is monitored in a broad energy range by a large bandwidth optical pulse. In this article, the possibility to combine the chemical sensitivity of intense tuneable X-rays pulses from a free electron laser, with the wide range of observables available in an ultrafast transmission electron microscope is discussed. The requirements for such experiments are quantified via estimates based on state of the art experiments and simulations, and it is proposed that ultrafast electron imaging, diffraction and spectroscopy experiments can be performed in combination with a chemically selective X-ray excitation of materials.
    Full-text · Article · Aug 2014 · Micron
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    ABSTRACT: We present the first experimental demonstration of MEMS-based magnetic optics for control of charged particle beams. Combined function (steering and focusing) 4-pole electromagnets with a 600-µm bore and 55-µm yoke thickness (686-µm magnetic length) have been fabricated with a novel MEMS process. These 3D solenoidal multi-pole electromagnets have demonstrated hysteresis-free adjustable 2D steering and focusing of a pC-charge 34-keV electron beam with 24-mT field intensity, 220-T/m field gradient, and potential for pulsed operation beyond 100 kHz. Simple geometric optimizations promise a 4-fold improvement in both field intensity and gradient without further scaling.
    Full-text · Conference Paper · Jun 2014
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    ABSTRACT: We report observations of strong-field effects in inverse Compton scattering via its X-ray characteristics using K-, L-edge, and attenuation filters. A CO2 laser of a0 ≈ 0.6 is collided by a 65-MeV electron beam.
    No preview · Conference Paper · Jun 2014
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    R. K. Li · P. Musumeci
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    ABSTRACT: Pushing the limits in temporal resolution for transmission electron microscopy (TEM) requires a revolutionary change in the electron source technology. In this paper we study the possibility of employing a radiofrequency photoinjector as the electron source for a time-resolved TEM. By raising the beam energy to the relativistic regime we minimize the space charge effects which otherwise limit the spatio-temporal resolution of the instrument. Analysis and optimization of the system taking into account the achievable beam brightness, electron flux on the sample, chromatic and spherical aberration of the electron optic system, and space charge effects in image formation are presented and supported by detailed numerical modeling. The results demonstrate the feasibility of 10 nanometer - 10 picosecond spatio-temporal resolution single-shot MeV TEM.
    Preview · Article · May 2014 · Physical Review Applied
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    ABSTRACT: This letter introduces a fabrication process for thick (>50 μm) multipole electromagnets that produce fields exceeding 20 mT across 0.2-mm3 free-space volumes. The novelty of the process involves the multistep thick-film electroplating of a magnetic alloy inside a high-density high-aspect-ratio solenoidal coil, producing high intensity fields across a larger volume than previous microelectromechanical systems electromagnets. To demonstrate an application enabled by this process, a 600-μm-gap four-pole electromagnet is fabricated, packaged, and used to steer a 34-keV electron beam.
    Full-text · Article · Apr 2014 · Journal of Microelectromechanical Systems
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    ABSTRACT: We discuss a two-color SASE free-electron laser (FEL) amplifier where the time and energy separation of two separated radiation pulses are controlled by manipulation of the electron beam phase space. Two electron beamlets with adjustable time and energy spacing are generated in an RF photo-injector illuminating the cathode with a comb-like laser pulse followed by RF compression in the linear accelerator. We review the electron beam manipulation technique to generate bunches with time and energy properties suitable for driving two-color FEL radiation. Experimental measurements at the SPARC-LAB facility illustrate the flexibility of the scheme for the generation of two-color FEL spectra.
    Full-text · Article · Mar 2014 · New Journal of Physics

Publication Stats

1k Citations
315.79 Total Impact Points

Institutions

  • 1998-2015
    • University of California, Los Angeles
      • • Department of Physics and Astronomy
      • • Department of Electrical Engineering
      Los Ángeles, California, United States
  • 2014
    • California State University, Los Angeles
      • Department of Physics and Astronomy
      Los Ángeles, California, United States
  • 2005-2007
    • Sapienza University of Rome
      • Department of Physics
      Roma, Latium, Italy
  • 1999
    • ENEA
      • Frascati Research Centre
      Frascati, Latium, Italy