641 research outputs found
SESAME, a third generation synchrotron light source for the Middle East region
Developed under the auspices of UNESCO, SESAME is being established as an autonomous international research centre in the Middle East/Mediterranean region. It will have as its centrepiece a 2.5 GeV third Generation synchrotron light source with 13 straight sections for insertion devices and an emittance of 26.6 nm-rad. It will provide intense radiation from the IR to hard X-rays to a community that is expected to exceed 1000 users a few years after the start of operation in 2008
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Status of the Variable Momentum Compaction Storage Ring Experiment in Spear
Studies on the Toxicity and Efficacy of a New Amino Acid Solution in Pediatric Parenteral Nutrition
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142223/1/jpen0368.pd
Influence of Solar-Geomagnetic Disturbances on SABER Measurements of 4.3 Micrometer Emission and the Retrieval of Kinetic Temperature and Carbon Dioxide
Thermospheric infrared radiance at 4.3 micrometers is susceptible to the influence of solar-geomagnetic disturbances. Ionization processes followed by ion-neutral chemical reactions lead to vibrationally excited NO(+) (i.e., NO(+)(v)) and subsequent 4.3 micrometer emission in the ionospheric E-region. Large enhancements of nighttime 4.3 m emission were observed by the TIMED/SABER instrument during the April 2002 and October-November 2003 solar storms. Global measurements of infrared 4.3 micrometer emission provide an excellent proxy to observe the nighttime E-region response to auroral dosing and to conduct a detailed study of E-region ion-neutral chemistry and energy transfer mechanisms. Furthermore, we find that photoionization processes followed by ion-neutral reactions during quiescent, daytime conditions increase the NO(+) concentration enough to introduce biases in the TIMED/SABER operational processing of kinetic temperature and CO2 data, with the largest effect at summer solstice. In this paper, we discuss solar storm enhancements of 4.3 micrometer emission observed from SABER and assess the impact of NO(+)(v) 4.3 micrometer emission on quiescent, daytime retrievals of Tk/CO2 from the SABER instrument
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Permanent magnet undulator for SPEAR
A 30 period permanent magnet (SmCo/sub 5/) undulator has been designed, built and tested. The period is 6.1 cm, overall length is 1.95 m, and the gap is variable from 2.7 cm to 6.0 cm. Magnetic measurements at the midplane with a 2.7 cm gap show that the field is sinusoidal with a peak value of .28 T. Construction details and magnetic measurements are presented along with the spectral distribution of radiation produced by 3.0 GeV electrons traversing the undulator
Quantum deformation of the angular distributions of synchrotron radiation. Emission of particles in the first excited state
The exact expressions for the characteristics of synchrotron radiation of
charged particles in the first excited state are obtained in analytical form
using quantum theory methods. We performed a detailed analysis of the angular
distribution structure of radiation power and its polarization for particles
with spin 0 and 1/2. It is shown that the exact quantum calculations lead to
results that differ substantially from the predictions of classical theory
Genetic Variants Associated With Vincristine‐Induced Peripheral Neuropathy in Two Populations of Children With Acute Lymphoblastic Leukemia
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149215/1/cpt1324_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149215/2/cpt1324.pd
Synchrotron radiation from a charge moving along a helical orbit inside a dielectric cylinder
The radiation emitted by a charged particle moving along a helical orbit
inside a dielectric cylinder immersed into a homogeneous medium is
investigated. Expressions are derived for the electromagnetic potentials,
electric and magnetic fields, and for the spectral-angular distribution of
radiation in the exterior medium. It is shown that under the Cherenkov
condition for dielectric permittivity of the cylinder and the velocity of the
particle image on the cylinder surface, strong narrow peaks are present in the
angular distribution for the number of radiated quanta. At these peaks the
radiated energy exceeds the corresponding quantity for a homogeneous medium by
some orders of magnitude. The results of numerical calculations for the angular
distribution of radiated quanta are presented and they are compared with the
corresponding quantities for radiation in a homogeneous medium. The special
case of relativistic charged particle motion along the direction of the
cylinder axis with non-relativistic transverse velocity (helical undulator) is
considered in detail. Various regimes for the undulator parameter are
discussed. It is shown that the presence of the cylinder can increase
essentially the radiation intensity.Comment: 18 pages, 8 EPS figure
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