979 research outputs found
Multifunction MMIC For Miniaturized Solid State Switch Matrix
This paper describes a new multifunction MMIC expressly designed for a reconfiguration matrix equipment.This MMIC has been developed using a standard PHEMT process and includes two switches,a totally switchable-off amplifier and a temperature compensation circuit.The complete circuit has also been designed to interface a standard CMOS control level. Performed simulations and obtained results demonstrate the effectiveness of this approach in reaching compactness and reliability of satellite equipment
NC pi0 Production in the MiniBooNE Antineutrino Data
The single largest background to future numubar to nuebar (numu to nue)
oscillation searches is neutral current pi0 production. MiniBooNE, which began
taking antineutrino data in January 2006, has the world's largest sample of
pi0's produced by antineutrinos in the 1 GeV energy range. These neutral pions
are primarily produced through the delta resonance but can also be created
through "coherent production." The latter process is the coherent sum of
glancing scatters of (anti)neutrinos off a neutron or proton, in which the
nucleus is kept intact but a pi0 is created. Current analysis of NC pi0
production in the MiniBooNE antineutrino data will be discussed.Comment: 4 pages, including 5 figures. Proceedings of the 5th International
Workshop on Neutrino-Nucleus Interactions in the Few-GeV Region (NuInt07),
Batavia, Illinois, 30 May - 3 Jun 200
Spectral functions for medium-sized nuclei
The spectral functions for calcium and argon are constructed. It is verified
that their predictions for the quasielastic electron-nucleus cross sections in
the energy range ~1 GeV agree with the data. The argon spectral function is
then used to obtain the quasielastic neutrino-nucleus cross section.Comment: 3 pages, 3 figures, presented at 5th International Workshop on
Neutrino-Nucleus Interactions in the Few-GeV Region (NuInt07), Fermilab, USA,
30.05-3.06.200
Energy Relaxation in the Integer Quantum Hall Regime
We investigate the energy exchanges along an electronic quantum channel
realized in the integer quantum Hall regime at filling factor . One of
the two edge channels is driven out-of-equilibrium and the resulting electronic
energy distribution is measured in the outer channel, after several propagation
lengths mm. Whereas there are no discernable energy
transfers toward thermalized states, we find efficient energy redistribution
between the two channels without particle exchanges. At long distances
m, the measured energy distribution is a hot Fermi function whose
temperature is lower than expected for two interacting channels, which suggests
the contribution of extra degrees of freedom. The observed short energy
relaxation length challenges the usual description of quantum Hall excitations
as quasiparticles localized in one edge channel.Comment: To be published in PRL, 10 pages including supplementary materia
Microscale generation of entangled photons without momentum conservation
We report, for the first time, the generation of entangled photon pairs via
type-0 spontaneous parametric down conversion in an ultra-thin wafer of lithium
niobate in which momentum between the pump photon and daughter photons is not
conserved. The characteristics of the emission are investigated using several
techniques. We find that non-phase matched SPDC is a promising source of
ultra-broadband two photon radiation that exhibits remarkably tight correlation
widths in both the spatial and temporal domains.Comment: 9 pages, 8 figure
Progress of the Felsenkeller shallow-underground accelerator for nuclear astrophysics
Low-background experiments with stable ion beams are an important tool for
putting the model of stellar hydrogen, helium, and carbon burning on a solid
experimental foundation. The pioneering work in this regard has been done by
the LUNA collaboration at Gran Sasso, using a 0.4 MV accelerator. In the
present contribution, the status of the project for a higher-energy underground
accelerator is reviewed. Two tunnels of the Felsenkeller underground site in
Dresden, Germany, are currently being refurbished for the installation of a 5
MV high-current Pelletron accelerator. Construction work is on schedule and
expected to complete in August 2017. The accelerator will provide intense, 50
uA, beams of 1H+, 4He+, and 12C+ ions, enabling research on astrophysically
relevant nuclear reactions with unprecedented sensitivity.Comment: Submitted to the Proceedings of Nuclei in the Cosmos XIV, 19-24 June
2016, Niigata/Japa
Generation of energy selective excitations in quantum Hall edge states
We operate an on-demand source of single electrons in high perpendicular
magnetic fields up to 30T, corresponding to a filling factor below 1/3. The
device extracts and emits single charges at a tunable energy from and to a
two-dimensional electron gas, brought into well defined integer and fractional
quantum Hall (QH) states. It can therefore be used for sensitive electrical
transport studies, e.g. of excitations and relaxation processes in QH edge
states
The effects of Gilles de la Tourette syndrome and other chronic tic disorders on quality of life across the lifespan:a systematic review
Gilles de la Tourette syndrome (GTS) and other chronic tic disorders are neurodevelopmental conditions characterized by the presence of tics and associated behavioral problems. Whilst converging evidence indicates that these conditions can affect patients' quality of life (QoL), the extent of this impairment across the lifespan is not well understood. We conducted a systematic literature review of published QoL studies in GTS and other chronic tic disorders to comprehensively assess the effects of these conditions on QoL in different age groups. We found that QoL can be perceived differently by child and adult patients, especially with regard to the reciprocal contributions of tics and behavioral problems to the different domains of QoL. Specifically, QoL profiles in children often reflect the impact of co-morbid attention-deficit and hyperactivity symptoms, which tend to improve with age, whereas adults' perception of QoL seems to be more strongly affected by the presence of depression and anxiety. Management strategies should take into account differences in age-related QoL needs between children and adults with GTS or other chronic tic disorders
Acoustic Phonon-Assisted Resonant Tunneling via Single Impurities
We perform the investigations of the resonant tunneling via impurities
embedded in the AlAs barrier of a single GaAs/AlGaAs heterostructure. In the
characteristics measured at 30mK, the contribution of individual donors
is resolved and the fingerprints of phonon assistance in the tunneling process
are seen. The latter is confirmed by detailed analysis of the tunneling rates
and the modeling of the resonant tunneling contribution to the current.
Moreover, fluctuations of the local structure of the DOS (LDOS) and Fermi edge
singularities are observed.Comment: accepted in Phys. Rev.
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