115,971 research outputs found

    Resolution changes in lithium-drifted silicon semiconductor detectors irradiated with 0.5, 1.0, 2.0, and 3.0 MeV electrons

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    Electron irradiation effect on resolution of lithium-drifted silicon semiconductor detector

    A monolithically integrated optical repeater

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    A monolithically integrated optical repeater has been fabricated on a single-crystal semi-insulating GaAs substrate. The repeater consists of an optical detector, an electronic amplifier, and a double heterostructure crowding effect laser. The repeater makes use of three metal semiconductor field effect transistors, one of which is used as the optical detector. With light from an external GaAlAs laser incident on the detector, an overall optical power gain of 10 dB from both laser facets was obtained

    Chemical Analysis of Surfaces Using Alpha Particles

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    Chemical analysis of surfaces using alpha particle interactions in instruments incorporating curium 242 alpha sources and semiconductor silicon detector

    Charge and spin state readout of a double quantum dot coupled to a resonator

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    State readout is a key requirement for a quantum computer. For semiconductor-based qubit devices it is usually accomplished using a separate mesoscopic electrometer. Here we demonstrate a simple detection scheme in which a radio-frequency resonant circuit coupled to a semiconductor double quantum dot is used to probe its charge and spin states. These results demonstrate a new non-invasive technique for measuring charge and spin states in quantum dot systems without requiring a separate mesoscopic detector

    Current responsivity of semiconductor superlattice THz-photon detectors

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    The current responsivity of a semiconductor superlattice THz-photon detector is calculated using an equivalent circuit model which takes into account the finite matching efficiency between a detector antenna and the superlattice in the presence of parasitic losses. Calculations performed for currently available superlattice diodes show that both the magnitudes and the roll-off frequencies of the responsivity are strongly influenced by an excitation of hybrid plasma-Bloch oscillations which are found to be eigenmodes of the system in the THz- frequency band. The expected room temperature values of the responsivity (2-3 A/W in the 1-3 THz-frequency band) range up to several percents of the quantum efficiency e/ωe/\hbar\omega of an ideal superconductor tunnel junction detector. Properly designed semiconductor superlattice detectors may thus demonstrate better room temperature THz-photon responsivity than conventional Schottky junction devices.Comment: Revtex file, uses epsf, 11 pages. 11 eps-figures; EPS-files generated by scanner, original higher resolution line drawings available from [email protected] by regular mail or fa

    Alpha particle backscattering measurements used for chemical analysis of surfaces

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    Alpha particle backscattering performs a chemical analysis of surfaces. The apparatus uses a curium source and a semiconductor detector to determine the energy spectrum of the particles. This in turn determines the chemical composition of the surface after calibration to known samples

    Ultrastable reference pulser for high-resolution spectrometers

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    Solid-state double-pulse generator for a high resolution semiconductor detector meets specific requirements for resolution /0.05 percent/, amplitude range /0.1-13 MeV/, and repetition rate /0.1-1000 pulses per second/. A tag pulse is generated in coincidence with each reference pulse

    Reverse Schottky-Asymmetry Spin Current Detectors

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    By reversing the Schottky barrier-height asymmetry in hot-electron semiconductor-metal-semiconductor ballistic spin filtering spin detectors, we have achieved: 1. Demonstration of >50% spin polarization in silicon, resulting from elimination of the ferromagnet/silicon interface on the transport channel detector contact, and 2. Evidence of spin transport at temperatures as high as 260K, enabled by an increase of detector Schottky barrier height.Comment: minor edits, additional ref

    Gamma ray detector modules

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    A radiation detector assembly has a semiconductor detector array substrate of CdZnTe or CdTe, having a plurality of detector cell pads on a first surface thereof, the pads having a contact metallization and a solder barrier metallization. An interposer card has planar dimensions no larger than planar dimensions of the semiconductor detector array substrate, a plurality of interconnect pads on a first surface thereof, at least one readout semiconductor chip and at least one connector on a second surface thereof, each having planar dimensions no larger than the planar dimensions of the interposer card. Solder columns extend from contacts on the interposer first surface to the plurality of pads on the semiconductor detector array substrate first surface, the solder columns having at least one solder having a melting point or liquidus less than 120 degrees C. An encapsulant is disposed between the interposer circuit card first surface and the semiconductor detector array substrate first surface, encapsulating the solder columns, the encapsulant curing at a temperature no greater than 120 degrees C

    Semiconductor projectile impact detector

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    A semiconductor projectile impact detector is described for use in determining micrometeorite presence, as well as its flux and energy comprising a photovoltaic cell which generates a voltage according to the light and heat emitted by the micrometeorites upon impact. A counter and peak amplitude measuring device were used to indicate the number of particules which strike the surface of the cell as well as the kinetic energy of each of the particles
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