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Nuclear Science, IEEE Transactions on

Issue 1 • Date Feb. 1993

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Displaying Results 1 - 9 of 9
  • Comments on ITS: "The integrated TIGER series of electron/photon transport codes-Version 3.0" by J.A. Halbleib et al., "CEPXS/ONELD Version 2.0: a discrete ordinates code packaging for general one-dimensional coupled electron-photon transport" by L.J. Lorence, Jr., and "Recent MCNP developments" by J.S. Bendricks and J.F. Briesmeister

    Publication Year: 1993 , Page(s): 71 - 72
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (155 KB)  

    Comments are offered on the three above-titled papers (ibid., vol.39, no.4, Aug. 1992). Regarding the first paper (p.1025-30), it is pointed out that a continuous-energy adjoint Monte Carlo code is available for electron transport, namely, the NOVICE code. The second paper (p.1031-4) gave performance information for a suite of 25 sample problems run on several mainframes and workstations. Performance data are given by the commenter for the same problems run on personal computers. Regarding the third paper (p.1035-40), the commenter points out that the three codes indicated there as available through the Radiation Shielding Information Center have PC versions.<> View full abstract»

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  • Evaluating parallel architectures for two real-time applications with 100 kHz repetition rate [hadron collider data]

    Publication Year: 1993 , Page(s): 45 - 55
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1088 KB)  

    In the context of research and development activities for future hadron colliders, competitive implementations of real-time algorithms for feature extraction have been made on various forms of commercial pipelined and parallel architectures. The algorithms used for benchmarking serve for decision making and are of relative complexity; they are required to run with a repetition rate of 100 kHz on data sets of kilobyte size. Results are reported and discussed in detail. Among the commercially available architectures, pipelined image processing systems can compete with custom-designed architectures. General-purpose processors with systolic mesh connectivity can also be used. Massively parallel systems of the SIMD type (many processors executing the same program on different data) are less suitable in the presently marketed form View full abstract»

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  • Application of neural networks to multiple alarm processing and diagnosis in nuclear power plants

    Publication Year: 1993 , Page(s): 11 - 20
    Cited by:  Papers (3)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (776 KB)  

    A feasibility study of multiple alarm processing and diagnosis using neural networks is presented. The backpropagation network (BPN) algorithm is applied to the training of multiple alarm patterns for the identification of faults in a reactor coolant pump (RCP) system. The general mapping capability of the neural network makes it possible to identify a fault easily. A number of case studies are performed, with emphasis on the applicability of the neural network to the pattern recognition of multiple alarms. Based on the case studies, the neural network can identify the cause of multiple alarms well, although untrained, incomplete/sensor-failed or time-varying alarm symptoms are given. Also, multiple faults are easily identified with a given alarm pattern View full abstract»

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  • A high-speed cadmium telluride radiation detector

    Publication Year: 1993 , Page(s): 56 - 62
    Cited by:  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (492 KB)  

    A small CdTe detector capable of high repetition pulse rate with possibilities for applications in radiation monitoring and similar uses was developed. The hole transit time through the crystal was shortened by decreasing the crystal thickness of 0.3 mm (1×1 mm) and by applying fields as high as 10 kV/cm. The electron transit time, although short, was electrically elongated by applying appropriate capacitance to the amplifier, and the output pulse waveform was designed to be similar to that for the holes. High, uniform output pulses with widths of 30 ns were thus obtained. The energy resolution was 9 keV for 59.4-keV photons from 241Am using a 100-ns-response amplifier View full abstract»

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  • The effects of funneling on space upset rate [microelectronics-space irradiation]

    Publication Year: 1993 , Page(s): 63 - 70
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (712 KB)  

    The complete three-dimensional analog of the usual upset rate integral is explored, exhibiting explicitly the average over solid angle which is often finessed or ignored. This permits a precise statement of how funneling can be included in the chord distribution, and an approximation is written which applies directly to the usual formalism. The mixed way that measured funneling contributes or does not contribute to input quantities is analyzed, and an algorithm is developed which includes funneling. Examples show what effects funneling adds to the no-funneling case View full abstract»

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  • X-ray energy separation method using a CdTe semiconductor X-ray imaging sensor and photon counting method

    Publication Year: 1993 , Page(s): 40 - 44
    Cited by:  Papers (1)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (396 KB)  

    A multichannel X-ray imaging sensor using a CdTe compound semiconductor radiation detector in photon counting mode was developed and tested for digital X-ray imaging and an X-ray energy separation capability. The X-ray imaging sensor was constructed of CdTe detector elements at a pitch of 0.25 mm. High band amplifiers, discriminators, and counters attached to each element formed the pulse counting circuit. Charge pulses generated by absorbed X-ray photons were directly counted and separated into two energy regions. Digitized X-ray images containing energy information were thus obtained. Using this sensor two separate X-ray images of different energy can be obtained simultaneously. A 256-channel X-ray imaging sensor was prepared and used to provide spatial resolution measurement for an X-ray charge. Low and high energy images of a hand phantom were thus obtained and both a soft tissue image and a bone image were produced using an energy subtraction method View full abstract»

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  • Development strategies of an expert system for multiple alarm processing and diagnosis in nuclear power plants

    Publication Year: 1993 , Page(s): 21 - 30
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (940 KB)  

    The development strategies of a prototype expert system, called ESAPD, for multiple alarm processing and diagnosis in nuclear power plants are described. The main objectives of the system are to assist operators in identifying a primary causal alarm among multiple fired alarms and to diagnose the plant malfunction quickly. The overall plant-wide diagnosis is performed at the alarm processing stage which can identify a primary causal alarm and can diagnose possible failure modes and failed systems and automatic interlock actions. The knowledge base for the alarm processing is represented as object-oriented concepts. The specific root cause diagnosis for the primary causal alarm can be performed at the alarm diagnosis stage. The system can provide operators with the possible causes of the primary causal alarm, emergency actions, and follow-up treatments. The diagnostic method adopted in this system is a hypothesize-and-test paradigm View full abstract»

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  • In situ computerized optical reflectivity measurement system for ion implantation

    Publication Year: 1993 , Page(s): 2 - 10
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (756 KB)  

    A computerized in situ optical reflectivity measurement system for the quantitative determination of material parameter changes of a substrate during the process of ion implantation is presented. These changes are related to the extent and nature of the induced crystal disorder in the substrate. The system consists of an optical reflectometer, with data acquisition and signal processing capabilities. For each sample a case history of the implant is obtained in the form of a continuous graph of reflectivity vs. a desired implantation parameter (e.g. dose). Examples regarding the implantation of 31P+ , 40Ar+, and 14N+ are presented. Additional suggestions for further system development and applications are made. Among the advantages of in situ measurements are the time-effort-expense. savings, a higher yield of experimental data per sample, higher accuracy, repeatability, and various possibilities of process control View full abstract»

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  • Object shape dependent PSF model for SPECT imaging

    Publication Year: 1993 , Page(s): 31 - 39
    Cited by:  Papers (32)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (788 KB)  

    An analytical expression for the point spread function (PSF) and the line spread function (LSF) of a parallel hole gamma camera is presented, for homogeneous media and for photons having mainly Compton interactions in the object. The PSF of scattered photons is described by convolving a zeroth-order modified Bessel function of the second kind with the unscattered PSF, which is approximated by a Gaussian. The complete PSF (scatter plus nonscatter) depends on the source distance ( z) and depth (d) of the source in the object. For convex-shaped emitting objects, the dependence of the PSF on the object contour can be incorporated by a simple correction. Thus, a complete mathematical model of the imaging of an activity distribution in a homogeneous medium is obtained. The model has been evaluated for 99mTechnetium line sources by using a LEAP collimator at various energy windows (ΔE). It is shown that the model is valid to a high accuracy at ΔE=15%, for a large range of values of z and d 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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