1,735 research outputs found
Characterization of transport of neutral and ionized species in reactive HiPIMS process
International audienceThe aim of the studyis to developa software to control in real time the thin film deposition of a plasma magnetron process. The thin films will be obtained by HiPIMS plasma process (High Power Impulse Magnetron Sputtering)[1]. Nowadays, it is the only physical process able to ensure optimal compliance ofthe coatings on complex 3D substrates. It is also easy to implement on industrial production lines thatare already equipped by conventional magnetron sputtering systems. In order to well understand this HiPIMS process and to control it by software, we will use three plasma diagnostics:absorption spectroscopy, mass spectrometry and optical emission spectroscopy(OES). The combination of the diagnostics will allow studying the behaviourof ions and neutrals created in the plasma and their transport in the spatial post-discharge. These measurements will serve to establish abacuses for the control software. We will also associate OES data with the conformity and properties of the coatings to verify if the latter could be linked with some OES lines, whose evolutions could be the signature of the imposed modifications
Analytic Kramer kernels, Lagrange-type interpolation series and de Branges spaces
The classical Kramer sampling theorem provides a method for obtaining orthogonal sampling formulas. In particular, when the involved kernel is analytic in the sampling parameter it can be stated in an abstract setting of reproducing kernel Hilbert spaces of entire functions which includes as a particular case the classical Shannon sampling theory. This abstract setting allows us to obtain a sort of converse result and to characterize when the sampling formula associated with an analytic Kramer kernel can be expressed as a Lagrange-type interpolation series. On the other hand, the de Branges spaces of entire functions satisfy orthogonal sampling formulas which can be written as Lagrange-type interpolation series. In this work some links between all these ideas are established
Synthesis of granulatimide bis-imide analogues
The synthesis of dipyrrolo[3,4-a:3,4-c]carbazole-1,3,4,6-tetraones, structurally related to granulatimide is reported. These compounds can be considered as granulatimide analogues in which a maleimide heterocycle replaces the imidazole moiety. The synthesis of pyridino[2,3-b]dipyrrolo[3,4-e:3,4-g]indole-1,3,4,6-tetraones is also reported. In these compounds, a 7-azaindole unit replaces the indole moiety present in the granulatimide and isogranulatimide structure
Ferromagnetic semiconductors
The current status and prospects of research on ferromagnetism in
semiconductors are reviewed. The question of the origin of ferromagnetism in
europium chalcogenides, chromium spinels and, particularly, in diluted magnetic
semiconductors is addressed. The nature of electronic states derived from 3d of
magnetic impurities is discussed in some details. Results of a quantitative
comparison between experimental and theoretical results, notably for Mn-based
III-V and II-VI compounds, are presented. This comparison demonstrates that the
current theory of the exchange interactions mediated by holes in the valence
band describes correctly the values of Curie temperatures T_C magnetic
anisotropy, domain structure, and magnetic circular dichroism. On this basis,
chemical trends are examined and show to lead to the prediction of
semiconductor systems with T_C that may exceed room temperature, an expectation
that are being confirmed by recent findings. Results for materials containing
magnetic ions other than Mn are also presented emphasizing that the double
exchange involving hoping through d states may operate in those systems.Comment: 18 pages, 8 figures; special issue of Semicon. Sci. Technol. on
semiconductor spintronic
Additive manufacturing of inorganic scintillator-based particle detectors
Inorganic scintillators are widely used for scientific, industrial and
medical applications. The development of 3D printing with inorganic
scintillators would allow fast creation of detector prototypes for registration
of ionizing radiation, such as alpha and beta, gamma particles in thin layers
of active material and soft X-ray radiation. This article reports on the
technical work and scientific achievements that aimed at developing a new
inorganic scintillation filament to be used for the 3D printing of composite
scintillator materials: study and definition of the scintillator composition;
development of the methods for the inorganic scintillator filament production
and further implementation in the available 3D printing technologies; study of
impact of the different 3D printing modes on the material scintillation
characteristics. Also, 3D printed scintillators can be used for creation of
combined detectors for high-energy physics.Comment: 14 pages, 16 figure
Search for muon-neutrino emission from GeV and TeV gamma-ray flaring blazars using five years of data of the ANTARES telescope
The ANTARES telescope is well-suited for detecting astrophysical transient
neutrino sources as it can observe a full hemisphere of the sky at all times
with a high duty cycle. The background due to atmospheric particles can be
drastically reduced, and the point-source sensitivity improved, by selecting a
narrow time window around possible neutrino production periods. Blazars, being
radio-loud active galactic nuclei with their jets pointing almost directly
towards the observer, are particularly attractive potential neutrino point
sources, since they are among the most likely sources of the very high-energy
cosmic rays. Neutrinos and gamma rays may be produced in hadronic interactions
with the surrounding medium. Moreover, blazars generally show high time
variability in their light curves at different wavelengths and on various time
scales. This paper presents a time-dependent analysis applied to a selection of
flaring gamma-ray blazars observed by the FERMI/LAT experiment and by TeV
Cherenkov telescopes using five years of ANTARES data taken from 2008 to 2012.
The results are compatible with fluctuations of the background. Upper limits on
the neutrino fluence have been produced and compared to the measured gamma-ray
spectral energy distribution.Comment: 27 pages, 16 figure
Results of the BiPo-1 prototype for radiopurity measurements for the SuperNEMO double beta decay source foils
The development of BiPo detectors is dedicated to the measurement of
extremely high radiopurity in Tl and Bi for the SuperNEMO
double beta decay source foils. A modular prototype, called BiPo-1, with 0.8
of sensitive surface area, has been running in the Modane Underground
Laboratory since February, 2008. The goal of BiPo-1 is to measure the different
components of the background and in particular the surface radiopurity of the
plastic scintillators that make up the detector. The first phase of data
collection has been dedicated to the measurement of the radiopurity in
Tl. After more than one year of background measurement, a surface
activity of the scintillators of (Tl) 1.5
Bq/m is reported here. Given this level of background, a larger BiPo
detector having 12 m of active surface area, is able to qualify the
radiopurity of the SuperNEMO selenium double beta decay foils with the required
sensitivity of (Tl) 2 Bq/kg (90% C.L.) with a six
month measurement.Comment: 24 pages, submitted to N.I.M.
The Antares Collaboration : Contributions to the 34th International Cosmic Ray Conference (ICRC 2015, The Hague)
The ANTARES detector, completed in 2008, is the largest neutrino telescope in the Northern hemisphere. Located at a depth of 2.5 km in the Mediterranean Sea, 40 km off the Toulon shore, its main goal is the search for astrophysical high energy neutrinos. In this paper we collect the 21 contributions of the ANTARES collaboration to the 34th International Cosmic Ray Conference (ICRC 2015). The scientific output is very rich and the contributions included in these proceedings cover the main physics results, ranging from steady point sources, diffuse searches, multi-messenger analyses to exotic physics
Measurement of the atmospheric muon depth intensity relation with the NEMO Phase-2 tower
The results of the analysis of the data collected with the NEMO Phase-2
tower, deployed at 3500 m depth about 80 km off-shore Capo Passero (Italy), are
presented. Cherenkov photons detected with the photomultipliers tubes were used
to reconstruct the tracks of atmospheric muons. Their zenith-angle distribution
was measured and the results compared with Monte Carlo simulations. An
evaluation of the systematic effects due to uncertainties on environmental and
detector parameters is also included. The associated depth intensity relation
was evaluated and compared with previous measurements and theoretical
predictions. With the present analysis, the muon depth intensity relation has
been measured up to 13 km of water equivalent.Comment: submitted to Astroparticle Physic
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