152 research outputs found
Stacking Simulations for Compton Positron sources of Future Linear Colliders
The Compton positron source of a future linear collider must obtain the target bunch population by accumulating a large number of positron packets, arriving either in a number of bursts from a ‘Compton ring’, with intermediate damping of the scattering electron beam, or quasicontinually from a ‘Compton energy recovery linac’. We present simulation results for the longitudinal stacking of Compton positrons in the ILC damping ring (DR) and the CLIC pre-damping ring (PDR), discussing parameter optimization, stacking efficiency, possible further improvements, and outstanding questions
Interference of diffraction and transition radiation and its application as a beam divergence diagnostic
We have observed the interference of optical diffraction radiation (ODR) and
optical transition radiation (OTR) produced by the interaction of a
relativistic electron beam with a micromesh foil and a mirror. The production
of forward directed ODR from electrons passing through the holes and wires of
the mesh and their separate interactions with backward OTR from the mirror are
analyzed with the help of a simulation code. By careful choice of the micromesh
properties, mesh-mirror spacing, observation wavelength and filter band pass,
the interference of the ODR produced from the unperturbed electrons passing
through the open spaces of the mesh and OTR from the mirror are observable
above a broad incoherent background from interaction of the heavily scattered
electrons passing through the mesh wires. These interferences (ODTRI) are
sensitive to the beam divergence and can be used to directly diagnose this
parameter. We compare experimental divergence values obtained using ODTRI,
conventional OTRI, for the case when front foil scattering is negligible, and
computed values obtained from transport code calculations and multiple screen
beam size measurements. We obtain good agreement in all cases.Comment: 40 pages 18 Figures. accepted for publication in PRSTA
Spontaneous Magnetization and Electron Momentum Density in 3D Quantum Dots
We discuss an exactly solvable model Hamiltonian for describing the
interacting electron gas in a quantum dot. Results for a spherical square well
confining potential are presented. The ground state is found to exhibit
striking oscillations in spin polarization with dot radius at a fixed electron
density. These oscillations are shown to induce characteristic signatures in
the momentum density of the electron gas, providing a novel route for direct
experimental observation of the dot magnetization via spectroscopies sensitive
to the electron momentum density.Comment: 5 pages (Revtex4), 4 (eps) figure
Tracking azimuthons in nonlocal nonlinear media
We study the formation of azimuthons, i.e., rotating spatial solitons, in
media with nonlocal focusing nonlinearity. We show that whole families of these
solutions can be found by considering internal modes of classical non-rotating
stationary solutions, namely vortex solitons. This offers an exhaustive method
to identify azimuthons in a given nonlocal medium. We demonstrate formation of
azimuthons of different vorticities and explain their properties by considering
the strongly nonlocal limit of accessible solitons.Comment: 11 pages, 7 figure
ПЛАНАРНЫЕ ФОТОКАТАЛИЗАТОРЫ С ФУНКЦИЕЙ НАКОПЛЕНИЯ ФОТОГЕНЕРИРОВАННОГО ЗАРЯДА
It is shown that nanostructured TiO2 : MoO3 films are capable to accumulate the charges induced under UV irradiation due to the generation of reduced forms of molybdenum oxide (hydrogen bronzes). Oxidation of these reduced forms in the air condition is accompanied by the generation of reactive oxygen species, due to which TiO2 : MoO3 films retain the oxidation ability and the pathophysiological activity for a long time after irradiation completion.Показано, что наноструктурированные пленки TiO2 : MoO3 способны под действием УФ-облучения накапливать фотоиндуцированный заряд при облучении за счет генерации восстановленных форм MoO3 (водородных бронз).Окисление указанных восстановленных форм в контакте с воздухом сопровождается генерацией активных форм кислорода, вследствие чего пленки TiO2 : MoO3 сохраняют окислительную способность и патофизиологическую активность в течение длительного времени (свыше 3 ч) после завершения облучения
Hantaviruses in Insectivore Populations in Siberia
Objective of the study was investigation of hantaviruses in a new natural reservoir - insectivores, their diversity and geographic distribution in the Western and Eastern Siberia. Materials and methods. Sorex shrews (71 specimens) were captured in Altai Republic, Altai, and Krasnoyarsk Territories, and Omsk Region. All samples were analyzed for hantavirus RNA using reverse transcription polymerase chain reaction with subsequent sequencing. Results and conclusions. A total of 12 viral RNA isolates from two Sorex species (S. araneus and S. roboratus) were genetically typed. Sequence analysis of the partial L and S segments identified two distinct hantaviruses. Kenkeme (KKMV) virus was detected in a flat-skulled shrew (S. roboratus) in Altai Territory. This virus was previously found in geographically remote sites in the Sakha Republic and China. New foci of Seewis virus circulation among common shrews (S. araneus), were found in the Omsk Region, Altai and Krasnoyarsk Territories. Previously published and new findings suggest that hantaviruses among shrews are widely distributed over the Russian Federation territory. The widespread circulation of SWSV and KKMV throughout Siberia is an important argument for investigation of their role in human infections
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