177 research outputs found
Influence of Halides on the Luminescence of Silver Molecular Clusters in Photo-Thermo-Refractive Glasses
The luminescence spectra of silver molecular clusters in photo-thermo-refractive glasses are investigated in detail before and after the UV irradiation and also after the heat treatment of the samples. Also investigat-ed are (I) the influence of halogens such as Cl and Br in glass matrix composition on the luminescence of sil-ver molecular clusters in photo-thermo-refractive glasses and (II) the effect of temperature on the lumines-cence spectra and the integrated intensity of luminescence of photo-thermo-refractive glasses.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3524
Luminescence of Silver Nanoclusters Formed by Ion Exchange Method in Cerium-doped and Undoped Glasses
The paper describes the research of influence of cerium ions in a silicate glass composition on the process
of formation silver nanoclusters and their optical properties. Effect ion exchange time and subsequent
heat treatment at temperature below transition temperature were investigated. The paper shows that in
cerium-doped glasses the rate of formation of silver nanoclusters higher than in the glass without cerium.
It explained by the shift of redox reaction of cerium and silver ions towards formation of atomic silver.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3524
Improving the Fermilab Booster Notching Efficiency, Beam Losses and Radiation Levels
Currently a fast vertical 1.08-m long kicker (notcher) located in the
Fermilab Booster Long-5 straight section is used to remove 3 out of 84
circulating bunches after injection to generate an abort gap. With magnetic
field of 72.5 Gauss it removes only 87% of the 3-bunch intensity at 400 MeV,
with 75% loss on pole tips of the focusing Booster magnets, 11% on the Long-6
collimators, and 1% in the rest of the ring. We propose to improve the notching
efficiency and reduce beam loss in the Booster by using two horizontal kickers
in the Long-12 section. The STRUCT calculations show that using such horizontal
notchers, one can remove up to 99% of the 3-bunch intensity at 400-700 MeV,
directing 96% of it to a new beam dump at the Long-13 section. This fully
decouples notching and collimation. The beam dump absorbs most of the impinging
proton energy in its jaws. The latter are encapsulated into an appropriate
radiation shielding that reduces impact on the machine components, personnel
and environment to the tolerable levels. The MARS simulations show that
corresponding prompt and residual radiation levels can be reduced ten times
compared to the current ones.Comment: 4 pp. 3rd International Particle Accelerator Conference (IPAC 2012)
20-25 May 2012. New Orleans, Louisian
Interferometer-Type Structures for Guided Atoms
We experimentally demonstrate interferometer-type guiding structures for
neutral atoms based on dipole potentials created by micro-fabricated optical
systems. As a central element we use an array of atom waveguides being formed
by focusing a red-detuned laser beam with an array of cylindrical microlenses.
Combining two of these arrays, we realize X-shaped beam splitters and more
complex systems like the geometries for Mach-Zehnder and Michelson-type
interferometers for atoms.Comment: 4 pages, 6 figure
Measurement of and Structure Functions in Low Region with the IHEP-JINR Neutrino Detector
The isoscalar structure functions and are measured as functions
of averaged over all permissible for the range of 6 to 28 GeV of
incident neutrino (anti-neutrino) energy at the IHEP-JINR Neutrino Detector.
The QCD analysis of structure function provides
MeV under the assumption of QCD
validity in the region of low . The corresponding value of the strong
interaction constant agrees with the
recent result of the CCFR collaboration and with the combined LEP/SLC result.Comment: 11 pages, 1 Postscript figure, LaTeX. Talk given at the 7th
International Workshop on Deep Inelastic Scattering and QCD (DIS 99),
Zeuthen, Germany, 19-23 Apr 199
Possibility of local pair existence in optimally doped SmFeAsO₁₋х in pseudogap regime
We report the analysis of pseudogap Δ* derived from resistivity experiments in FeAs-based superconductor SmFeAsO₀.₈₅, having a critical temperature Tc=55 K. Rather specific dependence Δ*(T) with two representative temperatures followed by a minimum at about 120 K was observed. Below Ts ≈ 147 K, corresponding to the structural transition in SmFeAsO, Δ*(T) decreases linearly down to the temperature TAFM ≈ 133 K. This last peculiarity can likely be attributed to the antiferromagnetic (AFM) ordering of Fe spins. It is believed that the found behavior can be explained in terms of Machida, Nokura, and Matsubara theory developed for the AFM superconductors
Determination of the high-twist contribution to the structure function
We extract the high-twist contribution to the neutrino-nucleon structure
function from the analysis of the data collected by
the IHEP-JINR Neutrino Detector in the runs with the focused neutrino beams at
the IHEP 70 GeV proton synchrotron. The analysis is performed within the
infrared renormalon (IRR) model of high twists in order to extract the
normalization parameter of the model. From the NLO QCD fit to our data we
obtained the value of the IRR model normalization parameter
. We
also obtained from a similar fit to the CCFR data. The average of both results is
.Comment: preprint IHEP-01-18, 7 pages, LATEX, 1 figure (EPS
Velocity-selective sublevel resonance of atoms with an array of current-carrying wires
Resonance transitions between the Zeeman sublevels of optically-polarized Rb
atoms traveling through a spatially periodic magnetic field are investigated in
a radio-frequency (rf) range of sub-MHz. The atomic motion induces the
resonance when the Zeeman splitting is equal to the frequency at which the
moving atoms feel the magnetic field oscillating. Additional temporal
oscillation of the spatially periodic field splits a motion-induced resonance
peak into two by an amount of this oscillation frequency. At higher oscillation
frequencies, it is more suitable to consider that the resonance is mainly
driven by the temporal field oscillation, with its velocity-dependence or
Doppler shift caused by the atomic motion through the periodic field. A
theoretical description of motion-induced resonance is also given, with
emphasis on the translational energy change associated with the internal
transition.Comment: 7 pages, 3 figures, final versio
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