83,192 research outputs found
Synchrotron radiation of crystallized beams
We study the modifications of synchrotron radiation of charges in a storage
ring as they are cooled. The pair correlation lengths between the charges are
manifest in the synchrotron radiation and coherence effects exist for
wavelengths longer than the coherence lengths between the charges. Therefore
the synchrotron radiation can be used as a diagnostic tool to determine the
state (gas, liquid, crystal) of the charged plasma in the storage ring. We show
also that the total power of the synchrotron radiation is enormously reduced
for crystallized beams. This opens the possibility of accelerating particles to
ultra-relativistic energies using small-sized cyclic accelerators.Comment: REVTeX, 27 pages, 6 figures, submitted to Phys. Rev.
Synchrotron Radiation from the Galactic Center in Decaying Dark Matter Scenario
We discuss the synchrotron radiation flux from the Galactic center in
unstable dark matter scenario. Motivated by the anomalous excess of the
positron fraction recently reported by the PAMELA collaboration, we consider
the case that the dark matter particle is unstable (and long-lived), and that
energetic electron and positron are produced by the decay of dark matter. Then,
the emitted electron and positron becomes the source of the synchrotron
radiation. We calculate the synchrotron radiation flux for models of decaying
dark matter, which can explain the PAMELA positron excess. Taking the lifetime
of the dark matter of O(10^26 sec), which is the suggested value to explain the
PAMELA anomaly, the synchrotron radiation flux is found to be O(1 kJy/str) or
smaller, depending on the particle-physics and cosmological parameters.Comment: 20 pages, 6 figure
Synchrotron radiation photoionization mass spectrometry of laser ablated species
The present paper describes an experimental apparatus suitable to create and study free clusters by combining laser ablation and synchrotron radiation. First tests on sulfur samples, S, showed the production, through laser ablation, of neutral Sn clusters (n = 1â8). These clusters were ionized using synchrotron radiation at photon energies from 160 eV to 175 eV, across the S 2p core edge. The feasibility of such combined ablationâsynchrotron radiation experiments is demonstrated, opening new possibilities on the investigation of free clusters and radical
Charge Determination of High Energy Electrons and Nuclei by Synchrotron Radiation with AMS
We investigate the possibilities to identify the charge of TeV electrons and
PeV nuclei using their synchrotron radiation in the earth's magnetic field.
Characteristics of synchrotron radiation photons are evaluated and methods of
detection are discussed.Comment: 9 pages, 6 figure
A leptonic-hadronic model for the afterglow of gamma-ray burst 090510
We model multiwavelength afterglow data from the short Gamma-Ray Burst (GRB)
090510 using a combined leptonic-hadronic model of synchrotron radiation from
an adiabatic blast wave. High energy, >100 MeV, emission in our model is
dominated by proton-synchrotron radiation, while electron-synchrotron radiation
dominates in the X ray and ultraviolet wavelengths. The collimation-corrected
GRB energy, depending on the jet-break time, in this model could be as low as
3e51 erg but two orders of magnitude larger than the gamma-ray energy. We also
calculated the opacities for electron-positron pair production by gamma rays
and found that TeV gamma rays from proton-synchrotron radiation can escape the
blast wave at early time, and their detection can provide evidence of a
hadronic emission component dominating at high energies.Comment: Accepted for publication in ApJ Lett. 5 pages, 2 figures, minor
changes, added reference
Experimental investigations of synchrotron radiation at the onset of the quantum regime
The classical description of synchrotron radiation fails at large Lorentz
factors, , for relativistic electrons crossing strong transverse
magnetic fields . In the rest frame of the electron this field is comparable
to the so-called critical field T. For quantum corrections are essential for the description of
synchrotron radiation to conserve energy. With electrons of energies 10-150 GeV
penetrating a germanium single crystal along the axis, we have
experimentally investigated the transition from the regime where classical
synchrotron radiation is an adequate description, to the regime where the
emission drastically changes character; not only in magnitude, but also in
spectral shape. The spectrum can only be described by quantum synchrotron
radiation formulas. Apart from being a test of strong-field quantum
electrodynamics, the experimental results are also relevant for the design of
future linear colliders where beamstrahlung - a closely related process - may
limit the achievable luminosity.Comment: 11 pages, 18 figures, submitted to PR
Suppression of synchrotron radiation due to beam crystallization
With respect to a "hot", non-crystallized beam the synchrotron radiation of a
cold crystallized beam is considerably modified. We predict suppression of
synchrotron radiation emitted by a crystallized beam in a storage ring. We also
propose experiments to detect this effect.Comment: LaTeX, 3 pages, 1 figure, To be published in Eur. Phys. J. A,
December 199
Synchrotron radiation: science & applications
This general talk is devoted to briefly introduce the main uses and applications of synchrotron radiation. An initial introduction will be dedicated to describe a synchrotron as a Large Facility devoted to produce photons that will be used to carry out excellent science.
The five outstanding main characteristics of synchrotron radiation are:
i) High brilliance and collimation
ii) Wavelength tunability
iii) Beamsize tunability
iv) Defined polarization
v) Time structure
vi) (Partial) coherence
These properties will be illustrated through selected examples ranging
from biomedicine (f.i. determination of the crystal structure of macromolecules from tiny crystals or cryo- nano tomography of individual cells by soft X-ray transmission microscopy)
to materials science (f.i. experiments of powder diffraction of materials under high pressure in diamond-anvil-cells),
from cultural heritage (f.i. the study of degradation of pigments in paints by X-ray absorption spectroscopy)
to cements (f.i. the hydration chemistry of eco-cements followed by in-situ powder diffraction),
and from basic research on magnetic materials (f.i. ferromagnets where the magnetism of individual metal transition elements are selectively followed by X-ray Magnetic Circular Dicroism)
to industrial applications on chocolate (f.i. small X-ray scattering as function of temperature of the polymorphs of cacao).Universidad de MĂĄlaga. Campus de Excelencia Internacional AndalucĂa Tech
Estimation of synchrotron-radiation background based on a real beam orbit
Some high-energy experiments have suffered from synchrotron-radiation
background. As a measure, we have developed a new calculation method of
synchrotron radiation based on a real beam orbit, aiming at quantitative
estimations and the construction of a possible alarm system for the background.
An explanation and a demonstration of our method are given.Comment: 6 pages, 7 figures, 2 table
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