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Nuclear Science, IEEE Transactions on

Issue 1 • Date Feb 1992

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Displaying Results 1 - 7 of 7
  • Nuclear microprobe imaging of single-event upsets

    Page(s): 7 - 12
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (512 KB)  

    An imaging technique has been developed which produces micron-resolution maps of where single-event upsets occur during ion irradiation of integrated circuits. From these `upset images' the identity and size of a circuit's upset-prone components can be directly determined. Utilizing a scanning nuclear microprobe, this imaging technique selectively exposes the lowest functional units of an integrated circuit (e.g. transistor drains, gates) and immediately measures the effect of a high-energy ion strike on circuit performance. Information about an integrated circuit's radiation hardness (i.e. total dose response and threshold upset LET), which has previously been acquired at the circuit level, can also be measured at the individual transistor level. Such detailed spatial characterization, provides a novel precision diagnostic technique with which to study single-event upset processes in integrated circuits View full abstract»

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  • The use of a Perovskite crystal as a detector for proton beam current

    Page(s): 25 - 28
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    Using a Perovskite crystal, a thermal detector has been designed for measurements of proton beam currents. For a given energy, the detector has a linear response with current intensity and an inverse response with chopping frequency. Measurements up to 50 nA (4.5 MeV H +) were carried out using a cyclotron, and a calibration curve is presented. The detector may be used over a wide range of energies, has a low cost, and is simple to construct. In addition, it can be used inside or outside vacuum, and it does not require an external bias field View full abstract»

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  • A general method for resonance power supply analysis

    Page(s): 29 - 34
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    The resonance power supply is widely used and proved to be an efficient method to supply accelerator magnets. The literature describes several power supply circuits, but no comprehensive theory of operation is presented. The authors present a mathematical method which describes the operation of the resonance power supply and its use for the accurate design of components View full abstract»

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  • SEU-hardened silicon bipolar and GaAs MESFET SRAM cells using local redundancy techniques

    Page(s): 2 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (396 KB)  

    Silicon bipolar and GaAs FET SRAMs have proven to be more difficult to harden with respect to single-event upset (SEU) mechanisms than have silicon CMOS SRAMs. This is a fundamental property of bipolar and JFET or MESFET device technologies which do not have a high-impedance, nonactive isolation between the control electrode and the current of voltage being controlled. All SEU circuit-level hardening techniques applied at the local cell level must use some type of information storage redundancy so that information loss on one node due to an SEU event can be recovered from information stored elsewhere in the cell. Several approaches to the use of local redundancy in bipolar and FET technologies are discussed. At the expense of increased cell complexity and increased power consumption and write time, several approaches are capable of providing complete SEU hardness at the local cell level View full abstract»

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  • An operator assistance system for beam adjustment of a cyclotron

    Page(s): 13 - 20
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    The authors discuss a computer-based operator system for cyclotron operators. The main feature of the system is a visual display of feasible setting regions (FSRs) of adjustable parameters. The FSR, derived from constraints among these parameters, shows the valid ranges where set points can be adjusted. Search traces by the operator are superimposed on the same screen as an aid to the operator's memory. In order to derive the FSR, first the cyclotron is modeled as a series of mappings of beam states, giving a conceptual description of the relation between beam states and constraints. Next, based on the model, the beam adjustment can be regarded as a search for the optimum mapping. This process is formulated as a nonlinear minimization problem; and its solution determines the FSR. Finally, to realize real-time display of the FSR, two methods which make the display response time shorter are proposed View full abstract»

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  • High-voltage pulsed life for multistressed polypropylene capacitor dielectric

    Page(s): 21 - 24
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    High-voltage polypropylene capacitors were aged under singular as well as simultaneous multiple stresses (electrical, thermal, and radiation) at the University at Buffalo's 2-MW thermal nuclear reactor. These stresses were combined neutron-gamma radiation with a total dose of 1.6×106 rad, electrical stress at 40 Vrms/μm, and thermal stress at 90°C. After exposure, the polypropylene dielectric was tested for life (number of pulses to fail) under high-voltage high-repetition-rate (100 pps) pulses. Pulsed life data were also compared with AC life data. Results show that radiation stress causes the most degradation in life, either acting alone or in combination with other stresses View full abstract»

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  • A capacitively coupled dose-rate-dependent transient upset mechanism in a bipolar memory

    Page(s): 35 - 39
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (412 KB)  

    A pattern sensitivity was observed in the threshold dose rate upset response of a bipolar 16 K PROM for radiation pulse widths of 20-100 ns. For the worst case pattern, the upset threshold was a factor of three lower than for the commonly used checkerboard pattern. The mechanism or this pattern sensitivity was found to be a capacitively coupled voltage transient on a sensitive node which caused a low-to-high transition at the output. A design fix was implemented to significantly alter the ratio of the two parasitic capacitances in a capacitive divider which reduced the amplitude of the voltage transient at the sensitive node. It was demonstrated that in the redesign, the pattern sensitivity was eliminated 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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