Holographic data storage in a DX-center material

We report on the optical storage of digital data in a semiconductor sample containing DX centers. The diffraction efficiency and the bit-error-rate performance of multiplexed data images are shown to agree well with a simple model of the material. Uniform storage without an exposure schedule is demonstrated. :The volume sensitivity is found to be similar to 10(3) times that of LiNBO3:Fe. The importance of coherent addition of scattered light with diffracted light in holographic data storage is discussed. (C) 1997 Optical Society of America

Photoconductance Quantization in a Single-Photon Detector

We have made a single-photon detector that relies on photoconductive gain in a narrow electron channel in an AlGaAs/GaAs 2-dimensional electron gas. Given that the electron channel is 1-dimensional, the photo-induced conductance has plateaus at multiples of the quantum conductance 2e$^{2}$/h. Super-imposed on these broad conductance plateaus are many sharp, small, conductance steps associated with single-photon absorption events that produce individual photo-carriers. This type of photoconductive detector could measure a single photon, while safely storing and protecting the spin degree of freedom of its photo-carrier. This function is valuable for a quantum repeater that would allow very long distance teleportation of quantum information.Comment: 4 pages, 4 figure

Observation Of A High-energy Cosmic-ray Family Caused By A Centauro-type Nuclear Interaction In The Joint Emulsion Chamber Experiment At The Pamirs

An exotic cosmic-ray family event is observed in the large emulsion chamber exposed by the joint at the Pamirs (4360 m above sea level). The family is composed of 120γ-ray-induced showers and 37 hadron-induced showers with individual visible energy exceeding 1 TeV. The decisive feature of the event is the hadron dominance: ΣEγ, ΣE(γ) h, 〈Eγ, 〈E(γ) h〉, 〈Eγ·Rγ〉 and 〈E(γ)·Rh〉 being 298 TeV, 476 TeV, 2.5 TeV, 12.9 TeV, 28.6 GeV m and 173 GeV m, respectively. Most probably the event is due to a Centauro interaction, which occured in the atmosphere at ∼700 m above the chamber. The event will constitute the second beautiful candidate for a Centauro observed at the Pamirs. © 1987.1901-2226233Bayburina, (1981) Nucl. Phys. B, 191, p. 1Lattes, Fujimoto, Hasegawa, Hadronic interactions of high energy cosmic-ray observed by emulsion chambers (1980) Physics Reports, 65, p. 151(1984) Trudy FIAN, 154, p. 1Borisov, (1984) Proc. Intern. Symp. on Cosmic rays and particle physics, p. 3. , TokyoRen, (1985) 19th Intern. Cosmic ray Conf., 6, p. 317. , La JollaYamashita, (1985) 19th Intern. Cosmic ray Conf., 6, p. 364. , La JollaTamada, (1977) Nuovo Cimento, 41 B, p. 245T. Shibata et al., to be publishedHillas, (1979) 16th Intern. Cosmic ray Conf., 6, p. 13. , KyotoBattiston, Measurement of the proton-antiproton elastic and total cross section at a centre-of-mass energy of 540 GeV (1982) Physics Letters B, 117, p. 126UA5 Collab., G.J. Alner et al., preprint CERN-EP/85-62Taylor, (1976) Phys. Rev. D, 14, p. 1217Burnett, (1984) Proc. Intern. Symp. on Cosmic rays and particle physics, p. 468. , Toky

Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection

A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)

Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

Phase Behavior of Aqueous Na-K-Mg-Ca-CI-NO3 Mixtures: Isopiestic Measurements and Thermodynamic Modeling

A comprehensive model has been established for calculating thermodynamic properties of multicomponent aqueous systems containing the Na{sup +}, K{sup +}, Mg{sup 2+}, Ca{sup 2+}, Cl{sup -}, and NO{sub 3}{sup -} ions. The thermodynamic framework is based on a previously developed model for mixed-solvent electrolyte solutions. The framework has been designed to reproduce the properties of salt solutions at temperatures ranging from the freezing point to 300 C and concentrations ranging from infinite dilution to the fused salt limit. The model has been parameterized using a combination of an extensive literature database and new isopiestic measurements for thirteen salt mixtures at 140 C. The measurements have been performed using Oak Ridge National Laboratory's (ORNL) previously designed gravimetric isopiestic apparatus, which makes it possible to detect solid phase precipitation. Water activities are reported for mixtures with a fixed ratio of salts as a function of the total apparent salt mole fraction. The isopiestic measurements reported here simultaneously reflect two fundamental properties of the system, i.e., the activity of water as a function of solution concentration and the occurrence of solid-liquid transitions. The thermodynamic model accurately reproduces the new isopiestic data as well as literature data for binary, ternary and higher-order subsystems. Because of its high accuracy in calculating vapor-liquid and solid-liquid equilibria, the model is suitable for studying deliquescence behavior of multicomponent salt systems

Fast sputter deposition of MoOx metal MoOx transparent electrodes on glass and PET substrates

Dielectric metal dielectric DMD transparent electrodes emerged as a compelling alternative to the widely used indium tin oxide ITO for solar cells and optoelectronic devices. DMD electrodes are especially attractive for flexible substrates, as, in contrast to ITO, they retain their low electrical resistance upon substrate bending and they do not require deposition at elevated temperatures. In a DMD, the choice of the dielectric is mainly dictated by the device architecture. Owing to its high work function, MoO3 is a commonly used hole selective dielectric layer. The present work investigates MoOx metal MoOx with 2 amp; 8201; lt; amp; 8201;x amp; 8201; lt; amp; 8201;3 DMD electrodes, with Ag and Au as metals, fabricated by direct current, magnetron sputtering, at industry relevant, high deposition rates. This was possible with a properly engineered MoOx target, providing high electrical conductivity and compactness. The sputtered electrodes on polyethylene terephthalate PET substrates show higher figure of merit than similar, evaporated electrodes in the literature. It is shown that the DMD electrodes with amorphous MoOx layers have low stability in water, but they are stable to other solvents, such as toluene, dimethylsulfoxide DMSO , dimethylformamide DMF , chlorobenzene or chloroform, allowing their implementation in devices like organic light emitting diodes or perovskite solar cells. Further, it is shown that the electrodes show dramatically enhanced mechanical stability compared to ITO, when subjected to tensile bending test