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Nuclear Science, IEEE Transactions on

Issue 1 • Date Feb 1991

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Displaying Results 1 - 6 of 6
  • Search for new inorganic scintillators

    Page(s): 30 - 31
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (188 KB)  

    It is shown that the search for new scintillators should profit from the considerable amount of data and insight on luminescent materials in the literature. Several examples are given. The efficiency of the search can then be substantially improved View full abstract»

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  • The Mark II silicon strip vertex detector and performance of a silicon detector telescope in the Mark II detector at the SLC

    Page(s): 25 - 29
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (348 KB)  

    A silicon strip vertex detector (SSVD) consisting of 36 independent silicon detector modules has been built for use in the Mark II detector at the SLAC Linear Collider (SLC). The performance of the individual modules and the stability and accuracy of their placement in the mechanical support are discussed. Top gain operational experience at the SLC, a telescope made of three silicon detector modules has been assembled and placed inside the Mark II. Results from the first data run of the SLC on the overall performance of the telescope, including backgrounds, charged particle tracking, and spatial resolution, are presented View full abstract»

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  • Effect of ionizing radiation on the electrical characteristics of polyvinylidene fluoride (PVF2)

    Page(s): 16 - 19
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (368 KB)  

    The influence of high-energy electron irradiation on the electrical properties of biaxially oriented polyvinylidene fluoride (PVF 2) film was investigated. The film was irradiated in air with a 1-MeV electron beam at a dose rate of 106 rad/min to different dose levels of up to 108 rad. Electrical properties measured included dielectric permittivity and dielectric loss, AC and DC breakdown voltages, and DC volume resistivity, X-ray diffraction and IR spectroscopy measurements were also made. The most pronounced of the radiation-induced changes were a decrease in like AC breakdown voltage and an increase in dielectric loss, both corresponding to increasing total absorbed dose. DC breakdown voltage and volume resistivity also showed noticeable changes. These changes are believed to be associated initially with a radiation-induced crystal phase transformation. This was confirmed by the X-ray diffraction curve and the IR spectra, which showed an increase in the β-phase and a decrease in the α-phase peaks at higher dose levels View full abstract»

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  • Characteristics of GaAs buffered FET logic (BFL) MESFETs and inverters exposed to high-energy neutrons

    Page(s): 20 - 24
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (456 KB)  

    A systematic investigation of the effects of high-energy neutrons on GaAs metal-semiconductor field-effect transistors (MESFETs) and buffered FET logic (BFL) gates has been carried out. Discrete transistors, inverters, and ring oscillators were characterized and modeled as a function of neutron fluence. Measurements were made of the threshold voltage shifts, the transconductance degradation, and saturation current degradation of GaAs depletion mode MESFETs, which comprise the BFL logic gates, irradiated with neutron fluences ranging from 5×1013 n/cm2 to 2×1015 n/cm2 (for particle energies above 10 keV). The threshold voltage was found to shift positively by 0.45 V, the transconductance decreased to 3%, and the saturation current to 1% of their unirradiated values at the highest neutron fluence (2×1015 n/cm2). The BFL inverter characteristics were measured and successfully simulated with SPICE using device parameters extracted from the neutron-damaged FETs. Ring oscillator measurements were made to determine the effects of high-energy neutrons on the frequency performance of BFL circuits. The ring oscillator frequency decreased to 9% of its unirradiated value at the highest neutron fluence View full abstract»

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  • A cross-validation procedure for stopping the EM algorithm and deconvolution of neutron depth profiling spectra

    Page(s): 9 - 15
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (424 KB)  

    The iterative EM (expectation maximization) algorithm is used to deconvolve neutron depth profiling spectra. Because of statistical noise in the data, artifacts in the estimated particle emission rate profile appear after too many iterations of the EM algorithm is stopped using a cross-validation procedure. The data are split into two independent halves. The EM algorithm is applied to one half of the data to get an estimate of the emission rates. The algorithm is stopped when the conditional likelihood of the other half of the data passes through its maximum. The roles of the two halves of the data are then switched to get a second estimate of the emission rates. The two estimates are then averaged View full abstract»

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  • A nuclear fragmentation energy deposition model

    Page(s): 2 - 8
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (400 KB)  

    A formalism for target fragment transport is presented with application to energy loss spectra in thin silicon devices. A nuclear database is recommended that agrees well with the measurements of P.J. McNulty et al. (1980) using surface barrier detectors. High-energy events observed by P.J. McNulty et al. (1981), which are not predicted by intranuclear cascade models, are well represented by this work View full abstract»

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IEEE Transactions on Nuclear Science focuses on all aspects of the theory and applications of nuclear science and engineering, including instrumentation for the detection and measurement of ionizing radiation; particle accelerators and their controls; nuclear medicine and its application; effects of radiation on materials, components, and systems; reactor instrumentation and controls; and measurement of radiation in space.

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