Search results for "ELECTRONICS"
showing 10 items of 4340 documents
Thermally and optically stimulated radiative processes in LiBaF3 crystals
2004
Abstract In LiBaF3 crystals both valence–core transitions (5.4– 6.5 eV ) and so-called self-trapped exciton luminescence (about 4.3 eV ) are important for practical application. Here, we present a study of 4.3 eV luminescence under photo- and thermostimulation after X-irradiation of undoped LiBaF3 crystals at various temperatures. Optically stimulated luminescence as a result of electron recombination with both self-trapped holes and holes localized at some defects, were observed after X-irradiation below 130 K and that of electron recombination with defect-localized holes was observed after X-irradiation above 130 K . The spectra of thermo-stimulated luminescence (TSL) contain a broad band…
Luminescence processes induced by UV radiation in A1N nanotips and nanorods
2008
Abstract The processes of the UV radiation induced photoluminescence, thermoluminescence and optically stimulated luminescence in the AlN nanotips and nanorods are studied in comparison with those in the AlN ceramics. The emission spectra of the UV radiation induced luminescence processes in the AlN nanostructures are similar to those of AlN ceramics, presumably originating from recombination processes with participation of the oxygen-related centres. In the nanostructures the luminescence processes occur mainly through the excitation of the host lattice, probably due to the smaller content of the randomly distributed defects in the lattice. The observed small mutual differences in the lumi…
Optical and magnetic resonance spectroscopy of stimulated recombination processes in defect studies
2004
Optical and magnetic resonance spectroscopy is widely used in the investigation of radiation-induced processes in wide-gap solids. This paper discusses the present understanding of applications of the experimental methods of optical and thermoactivation spectroscopy in the research of new materials, for applications in radiation dosimetry and digital imaging and in the basic research into the fundamental physics and chemistry of radiation. The advantages of the simultaneous use of optical and magnetic resonance techniques for the investigation of stimulated processes are considered.
A complementary laser system for ISOLDE RILIS
2011
The Resonance Ionization Laser Ion Source (RILIS) is a powerful tool for efficient and selective production of radioactive ion beams at Isotope Separator On Line (ISOL) facilities. To avoid isobaric background, highly selective stepwise resonant ionization is applied, using up to three different laser wavelengths. Due to their advantages in terms of stability and reliability, an all solid-state titanium:sapphire (Ti:Sa) system is used or is planned to be installed at the majority of on-line facilities worldwide. Such an all solid-state Ti:Sa laser system is going to be installed at the ISOLDE RILIS at CERN alongside the well-established dye laser system.
Twin GEM-TPC prototype (HGB4) beam test at GSI and Jyväskylä : a development for the Super-FRS at FAIR
2017
The FAIR[1] facility is an international accelerator centre for research with ion and antiproton beams. It is being built at Darmstadt, Germany as an extension to the current GSI research institute. One major part of the facility will be the Super-FRS[2] separator, which will be include in phase one of the project construction. The NUSTAR experiments will benefit from the Super-FRS, which will deliver an unprecedented range of radioactive ion beams (RIB). These experiments will use beams of different energies and characteristics in three different branches; the high-energy which utilizes the RIB at relativistic energies 300-1500 MeV/u as created in the production process, the low-energy bra…
Mechanically stable metal layers for ohmic and blocking contacts on CdZnTe detectors by electroless deposition
2015
CdZnTe detectors are commonly exploited for the detection of gamma rays. However, obtaining mechanical stable, low noise contacts on CdZnTe is still an issue. In particular, ohmic contacts would be preferable for high flux applications. In this work, we show that it is possible to obtain mechanical stable gold contacts by electroless deposition in methanol solution. Moreover, we show that electroless deposited nickel contacts are also mechanical stable and are good candidates for the realization of ohmic contacts on high resistivity CdZnTe crystals.
Charge carrier transport mechanisms in CdZnTe detectors grown by the vertical Bridgman technique
2016
In this work, we report on the results of electrical characterization of CdZnTe (CZT) detectors, with gold electroless contacts, grown by the boron oxide encapsulated vertical Bridgman technique (B-VB), currently produced at IMEM-CNR (Parma, Italy). The detectors, with different thicknesses (1 and 2.5 mm), have the same electrode layout: the anode is a central electrode (2 x 2 mm(2)) surrounded by a guard ring electrode. The cathode is a planar electrode covering the detector surface (4.1 x 4.1 mm(2)). Current-voltage (I-V) characteristics were measured at different temperatures in order to study the charge transport and the electrical properties. These detectors were compared with the trav…
Optical rogue-wave-like extreme value fluctuations in fiber Raman amplifiers
2008
International audience; We report experimental observation and characterization of rogue wave-like extreme value statistics arising from pump-signal noise transfer in a fiber Raman amplifier. Specifically, by exploiting Raman amplification with an incoherent pump, the amplified signal is shown to develop a series of temporal intensity spikes whose peak power follows a power-law probability distribution. The results are interpreted using a numerical model of the Raman gain process using coupled nonlinear Schrödinger equations, and the numerical model predicts results in good agreement with experiment.
Experimental signatures of extreme optical fluctuations in lumped Raman fiber amplifiers
2012
International audience; In this work, we experimentally investigate several temporal and spectral methods to highlight extreme fluctuations which can develop during the Raman amplification of an ultrashort pulse train. Forward and backward pumping schemes are compared to dual pass configurations.
Raman-assisted three-wave mixing of non-phase-matched waves in optical fibres: application to wide-range frequency conversion
2001
International audience; We analyse theoretically and experimentally the Raman-assisted parametric coupling between non-phase-matched waves propagating in normally dispersive single-mode fibres. We perform a careful analysis of the wave-coupling behaviour, which shows that scalar and vector three-wave mixing (TWM) interactions induce a relatively small periodic power flow between a central-frequency pump at frequency ω0 and a pair of up-shifted (anti-Stokes) and down-shifted (Stokes) sidebands at frequencies View the MathML source and View the MathML source, respectively. For sufficiently high pump powers, the stimulated Raman scattering enters into play, causing a unilateral transfer of ene…