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Transformation as a Design Process and Runtime Architecture for High Integrity Software (open access)

Transformation as a Design Process and Runtime Architecture for High Integrity Software

We have discussed two aspects of creating high integrity software that greatly benefit from the availability of transformation technology, which in this case is manifest by the requirement for a sophisticated backtracking parser. First, because of the potential for correctly manipulating programs via small changes, an automated non-procedural transformation system can be a valuable tool for constructing high assurance software. Second, modeling the processing of translating data into information as a, perhaps, context-dependent grammar leads to an efficient, compact implementation. From a practical perspective, the transformation process should begin in the domain language in which a problem is initially expressed. Thus in order for a transformation system to be practical it must be flexible with respect to domain-specific languages. We have argued that transformation applied to specification results in a highly reliable system. We also attempted to briefly demonstrate that transformation technology applied to the runtime environment will result in a safe and secure system. We thus believe that the sophisticated multi-lookahead backtracking parsing technology is central to the task of being in a position to demonstrate the existence of HIS.
Date: April 5, 1999
Creator: Bespalko, Stephen J. & Winter, Victor L.
System: The UNT Digital Library
The Discovery of a Nearby M Dwarf (open access)

The Discovery of a Nearby M Dwarf

This article reports the serendipitous discovery of a nearby M dwarf star, found while observing the old nova DN Gem at the Wise Observatory.
Date: April 1999
Creator: Shemmer, Ohad & Kaspi, Shai
System: The UNT Digital Library
Developing the VirtualwindoW into a General Purpose Telepresence Interface (open access)

Developing the VirtualwindoW into a General Purpose Telepresence Interface

An important need while using robots or remotely operated equipment is the ability for the operator or an observer to easily and accurately perceive the operating environment. A classic problem in providing a complete representation of a work area is sensory overload or excessive complexity in the human–machine interface. In addition, remote operations often benefit from depth perception capability while viewing or manipulating objects. Thus, there is an on going effort within the robotic field to develop simplified telepresence interfaces. The Department of Energy’s Idaho National Engineering and Environmental Laboratory (INEEL) has been researching methods to generalize a human-machine interface for telepresence applications. Initial telepresence research conducted at the INEEL developed and implemented a concept called the VirtualwindoW. This system minimized the complexity of remote stereo viewing controls and provided the operator the “feel” of viewing the environment, including depth perception, in a natural setting. The VirtualwindoW has shown that the human-machine interface can be simplified while increasing operator performance. This paper deals with the continuing research and development of the VirtualwindoW to provide a generalized, reconfigurable system that easily utilizes commercially available components. The original system has now been expanded to include support for zoom lenses, camera blocks, wireless …
Date: April 1, 1999
Creator: Kinoshita, Robert Arthur; Anderson, Matthew Oley; Mckay, Mark D & Willis, Walter David
System: The UNT Digital Library
The Integration of an Electro-hydraulic Manipulator Arm into a Self-contained Mobile Delivery System (open access)

The Integration of an Electro-hydraulic Manipulator Arm into a Self-contained Mobile Delivery System

The Portable Articulated Arm Deployment System (PAADS) is a remotely controlled vehicle for delivering a tele-operated electro-hydraulic manipulator arm to a field deployable location. The self-contained system includes a boom vehicle with long reach capability, an electro-hydraulic manipulator arm, closed circuit television (CCTV) systems, and onboard tools. On board power systems consist of a self contained, propane fired 8 KW generator and an air compressor for pneumatic tools. The generator provides the power to run the air compressor as well as provide power to operate the 110 VAC auxiliary lighting system for the video cameras. The separate control console can be located up to 500 ft from the vehicle. PAADS is a fully integrated system, containing all equipment required to perform complex field operations. Hydraulic integration of the manipulator arm into the vehicle hydraulic drive system was necessary to eliminate the tether management of hoses, which extended vehicle operating range, minimized hydraulic pressure losses, and provided the opportunity to go to a radio frequency (RF) control system in the future, thereby eliminating the control cable. This paper presents the key decision points during system development. Emphasis is placed on ease of operator control and not on an intelligent machine approach. …
Date: April 1, 1999
Creator: Borland, Mark Wilson & Berry, Stephen Michael
System: The UNT Digital Library
Working Group VI Summary Report: New Ideas Employing High-Power Lasers (open access)

Working Group VI Summary Report: New Ideas Employing High-Power Lasers

The objectives of this working group were to provide the ''Future Light Source Community'' information on: Electron-Laser interaction based sources; Plasma based radiation sources and accelerators; and Present and future high-power laser technology. A summary of presentations, discussions and opinions is presented next. At the end of this report, a few references are given. The list is very far from being complete but is meant as a start for further exploring the various topics discussed in this working group. Based on presentations and discussions during the workshop, a summarizing table of the performance of three different types of laser systems has been made. The emphasis is on listing performance parameters of solid state, FEL and gas based lasers, relevant to the development of a future fourth generation light source. Two types of solid state lasers capable of producing peak power in the multi-terawatt range are described: Nd:glass and Ti:sapphire lasers [1]. The main development for these lasers is towards higher average power levels: from the 10 W to the > 100 W level. An infrared FEL has recently produced 1 kW average power but with peak power on the order of 0.1 GW [2]. A terawatt class, short pulse CO{sub …
Date: April 9, 1999
Creator: Leemans, W. P.
System: The UNT Digital Library
In Situ Site Characterization Technologies Demonstrated at the INEEL in Decommissioning Projects (open access)

In Situ Site Characterization Technologies Demonstrated at the INEEL in Decommissioning Projects

The United States Department of Energy (DOE)continually seeks safer, more cost-effective, and better performing technologies for decontamination and decommissioning (D&D) of nuclear facilities. The Deactivation and Decommissioning Focus Area (DDFA) of the DOE Federal Energy Technology Center (FETC) sponsors Large Scale Demonstration and Deployment Projects (LSDDPs) which are conducted at various DOE sites. The Idaho National Engineering and Environmental Laboratory (INEEL) is one of the DOE sites for demonstration of these newa and improved technologies. The INEEL needs statement defines specific needs or problems for their D&D program. One of the needs identified at the INEEL was for new or improved site characterization technologies. A variety of in-situ site characterization technologies have been demonstrated through the INEEL LSDDP. These technologies provide a safer means of characterization, improved documentation, real-time information, improved D&D schedules, and reduction in costs and radiation exposures to workers. These technologies have provided vast improvements to the D&D site characterizations. Some of these technologies include: • The Global Positioning Radiometric Scanner System for large-area, surface gamma radiation surveys • Remote underwater characterization system• Identifying heavy metals in painted surfaces and determining the alloy composition in metallic material • In-Situ Object Counting System for free release • Real-time …
Date: April 1, 1999
Creator: Wright, Kelly Clyde; Meservey, Richard Harlan & Whitmill, Larry Joseph
System: The UNT Digital Library
RGUI 1.0, New Graphical User Interface for RELAP5-3D (open access)

RGUI 1.0, New Graphical User Interface for RELAP5-3D

With the advent of three-dimensional modeling in nuclear safety analysis codes, the need has arisen for a new display methodology. Currently, analysts either sort through voluminous numerical displays of data at points in a region, or view color coded interpretations of the data on a two-dimensional rendition of the plant. RGUI 1.0 provides 3D capability for displaying data. The 3D isometric hydrodynamic image is built automatically from the input deck without additional input from the user. Standard view change features allow the user to focus on only the important data. Familiar features that are standard to the nuclear industry, such as run, interact, and monitor, are included. RGUI 1.0 reduces the difficulty of analyzing complex three dimensional plants.
Date: April 1, 1999
Creator: Mesina, George Lee & Galbraith, James Andrew
System: The UNT Digital Library
Mobile Robotic Teams Applied to Precision Agriculture (open access)

Mobile Robotic Teams Applied to Precision Agriculture

The Idaho National Engineering and Environmental Laboratory (INEEL) and Utah State University’s Center for Self-Organizing and Intelligent Systems (CSOIS) have developed a team of autonomous robotic vehicles applicable to precision agriculture. A unique technique has been developed to plan, coordinate, and optimize missions in large structured environments for these autonomous vehicles in realtime. Two generic tasks are supported: 1) Driving to a precise location, and 2) Sweeping an area while activating on-board equipment. Sensor data and task achievement data is shared among the vehicles enabling them to cooperatively adapt to changing environmental, vehicle, and task conditions. This paper discusses the development of the autonomous robotic team, details of the mission-planning algorithm, and successful field demonstrations at the INEEL.
Date: April 1, 1999
Creator: Anderson, Matthew Oley; Kinoshita, Robert Arthur; Mckay, Mark D; Willis, Walter David; Gunderson, R.W. & Flann, N.S.
System: The UNT Digital Library
Enhanced Reductive Dechlorination of TCE in a Basalt Aquifer (open access)

Enhanced Reductive Dechlorination of TCE in a Basalt Aquifer

A field evaluation of enhanced reductive dechlorination of trichloroethene (TCE) in ground water has been in progress since November 1998 to determine whether in situ biodegradation can be significantly enhanced through the addition of an electron donor (lactate). An in situ treatment cell was established in the residual source area of a large TCE plume in a fractured basalt aquifer utilizing continuous ground water extraction approximately 150 meters downgradient of the injection location. After a 1-month tracer test and baseline sampling period, the pulsed injection of lactate was begun. Ground water samples were collected from 11 sampling points on a biweekly basis and in situ water quality parameters were recorded every 4 hours at two locations. Within 2 weeks after the initial lactate injection, dissolved oxygen and redox potential were observed to decrease substantially at all sampling locations within 40 m of the injection well. Decreases in nitrate and sulfate concentrations were also observed. Both quantitative in situ rate estimation methods and qualitative measures such as changes in redox conditions, decreases in chlorine number, and changes in biomass indicator parameters are being used throughout the test to evaluate the extent to which biodegradation of TCE is enhanced.
Date: April 1, 1999
Creator: Sorenson, Kent Soren; Peterson, Lance Nutting & Ely, R. L.
System: The UNT Digital Library
The VirtualwindoW: A Reconfigurable, Modular, Stereo Vision System (open access)

The VirtualwindoW: A Reconfigurable, Modular, Stereo Vision System

An important need while using unmanned vehicles is the ability for the remote operator or observer to easily and accurately perceive the operating environment. A classic problem in providing a complete representation of the remote work area is sensory overload or excessive complexity in the human-machine interface. In addition, remote operations often benefit from depth perception capability while viewing or manipulating objects. Thus, there is an on going effort within the remote and teleoperated robotic field to develop better human-machine interfaces. The Department of Energy's Idaho National Engineering and Environmental Laboratory (INEEL) has been researching methods to simplify the human-machine interface using atypical operator techniques. Initial telepresence research conducted at the INEEL developed and implemented a concept called the VirtualwindoW. This system minimized the complexity of remote stereo viewing controls and provided the operator the "feel" of viewing the environment, including depth perception, in a natural setting. The VirtualwindoW has shown that the human-machine interface can be simplified while increasing operator performance. This paper deals with the continuing research and development of the VirtualwindoW to provide a reconfigurable, modular system that easily utilizes commercially available off the shelf components. This adaptability is well suited to several aspects of unmanned vehicle …
Date: April 1, 1999
Creator: Kinoshita, Robert Arthur; Anderson, Matthew Oley; Mckay, Mark D & Willis, Walter David
System: The UNT Digital Library
A problem of stand-off energy sources for MTF (open access)

A problem of stand-off energy sources for MTF

Fusion devices based on the adiabatic (or shock) compression of the plasma by electromagnetically driven liner need specific energy sources capable of delivering a high current (~10 MA) in the pulses 0.1 - 1 microsecond long. In the present experimental facilities, the plasma load is situated very close to the pulse-power energy source. In the future fusion devices, one would have to place a plasma load at a considerable distance from the energy source (to avoid strong neutron and thermo-mechanical damage to the source). Several versions of the stand-off energy sources are considered. All are based on the idea of an "assembly" - an object where the plasma load is nested and which contains all necessary circuitry that allows conversion of the energy delivered to the assembly into the magnetic energy. Such "assemblies" will be dropped (or inserted) into the reaction chamber at a desired rate and energized by a stand-off energy source. Four specific concepts have been mentioned.
Date: April 9, 1999
Creator: Ryutov, D. D.
System: The UNT Digital Library
Cosmological constraints on theories with large extra dimensions (open access)

Cosmological constraints on theories with large extra dimensions

In theories with large extra dimensions, constraints from cosmology lead to non-trivial lower bounds on the gravitational scale M, corresponding to upper bounds on the radii of the compact extra dimensions. These constraints are especially relevant to the case of two extra dimensions, since only if M is 10 TeV or less do deviations from the standard gravitational force law become evident at distances accessible to planned sub-mm gravity experiments. By examining the graviton decay contribution to the cosmic diffuse gamma radiation, we derive, for the case of two extra dimensions, a conservative bound M > 110TeV, corresponding to r{sub 2} < 5.1 x 10{sup -5} mm, well beyond the reach of these experiments. We also consider the constraint coming from graviton overclosure of the universe and derive an independent bound M > 6.5/{radical}h TeV, or r{sub 2} < .015hmm.
Date: April 23, 1999
Creator: Hall, Lawrence J. & Smith, David
System: The UNT Digital Library
Work-Op IV summary: lessons from iron opacities (open access)

Work-Op IV summary: lessons from iron opacities

The fourth international LTE opacity workshop and code comparison study, WorkOp-IV, was held in Madrid in 1997. Results of this workshop are summarized with a focus on iron opacities. In particular, the astrophysically important photon absorption region between 50 and 80 eV is emphasized for a sequence of iron plasmas at densities and temperatures that produce nearly the same average ionization stage (Z* {approximately} 8.6). Experimental data that addressed this spectral region is also reviewed.
Date: April 16, 1999
Creator: Davidson, S J; Iglesias, C A; Minguez, E & Serduke, F J D
System: The UNT Digital Library
U.S./Russian cooperative efforts to enhance nuclear MPC&A at VNIITF, (Chelyabinsk-70) (open access)

U.S./Russian cooperative efforts to enhance nuclear MPC&A at VNIITF, (Chelyabinsk-70)

The work described here is part of an effort called the Nuclear Materials Protection, Control, and Accounting (MPC&A) Program, a cooperative program between the US Department of Eenrgy (DOE) and Russia's Ministry of Atomic Energy (MinAtom). The objective of the program is to reduce the risk of nuclear proliferation by strengthening MPC&A systems at Russian nuclear Facilities. This paper describes that portion of the MPC&A program that is directed specifically to the needs of the All Russian Scientific Research Institute of Technical Physics (VNIITF), also called Chelyabinsk-70. A major MPC&A milestone was met at VNIITF when the MPC&A improvements were commissioned at the Pulse Research Reactor Facility in May of this year.
Date: April 20, 1999
Creator: Abramson, B.; Apt, K.; Blasy, J.; Bukin, D.; Churikov, Y.; Curtis, D. et al.
System: The UNT Digital Library
Prospects for Advanced RF Theory and Modeling (open access)

Prospects for Advanced RF Theory and Modeling

This paper represents an attempt to express in print the contents of a rather philosophical review talk. The charge for the talk was not to summarize the present status of the field and what we can do, but to assess what we will need to do in the future and where the gaps are in fulfilling these needs. The objective was to be complete, covering all aspects of theory and modeling in all frequency regimes, although in the end the talk mainly focussed on the ion cyclotron range of frequencies (ICRF). In choosing which areas to develop, it is important to keep in mind who the customers for RF modeling are likely to be and what sorts of tasks they will need for RF to do. This occupies the first part of the paper. Then we examine each of the elements of a complete RF theory and try to identify the kinds of advances needed.
Date: April 12, 1999
Creator: Batchelor, D.B.
System: The UNT Digital Library
The relationship between intraseasonal and interannual variability during the asian summer monsoon (open access)

The relationship between intraseasonal and interannual variability during the asian summer monsoon

The purpose of this paper is to investigate intraseasonal (30-70 days) and higher frequency (5-30 days) variability and its relationship to interannual variability. Various modelling studies have suggested a link between intraseasonal and interannual variability of the Asian summer monsoon. This relationship has been mainly based upon the similar spatial structures of the dominant EOF patterns of the monsoon circulation on intraseasonal and interannual time scales from simulations with simple models and atmospheric general circulation models. Here we investigate these relationships using 40 years of NCEP/NCAR Reanalysis. Motivation for this study is embodied in the suggestions of Charney and Shukla (1981) that boundary forcing (e.g., sea surface temperature) may predispose the monsoon system towards a dry or wet state, and the result of Palmer (1994), using the Lorenz (1963) model, that the probability of being in one regime of phase space or another is no longer equally probable in the presence of external forcing. To investigate the influence of the boundary forcing, the probability distribution functions (PDF�s) of the principal components are given.
Date: April 21, 1999
Creator: Annamalai, H; Slingo, J M & Sperber, K R
System: The UNT Digital Library
Proliferation prevention in the commercial fuel cycle (open access)

Proliferation prevention in the commercial fuel cycle

This website contains the papers presented on November 17, 1998 during the session, "Proliferation Prevention in the Commercial Fuel Cycle," at the American Nuclear Society meeting in Washington, DC. The abstracts are in a separate section; individual papers also contain the author's bio and e-mail address. In the session planning phase, it was suggested that the following questions and other relevant issues be addressed: * What are the difficulties and issues with defining and enforcing international standards for the physical protection of Pu and HEU (beyond the Convention on the Physical protection of Nuclear Material, which primarily addresses transportation)? * How do we (or can we) keep nuclear technology in general, and reprocessing and enrichment technologies in particular, from spreading to undesirable organizations (including governments), in light of Article IV of the NPT? Specifically, can we (should we) prevent the construction of light-water reactors in Iran; and should we support the construction of light-water reactors in North Korea? * Are there more proliferation-resistant fuel cycles that would be appropriate in developing countries? * Can the concept of "nonproliferation credentials" be defined in a useful way? * Is there historical evidence to indicate that reprocessing (or enrichment of HEU) in the …
Date: April 9, 1999
Creator: Sutcliffe, W G
System: The UNT Digital Library
The advantages of evaporation of Hafnium in a reactive environment to manufacture high damage threshold multilayer coatings by electron-beam deposition (open access)

The advantages of evaporation of Hafnium in a reactive environment to manufacture high damage threshold multilayer coatings by electron-beam deposition

None
Date: April 22, 1999
Creator: Bevis, R. P.; Sheehan, L. M.; Smith, D. J.; Stolz, C. J. & Von Gunten, M. K.
System: The UNT Digital Library
Demonstration Integrated Knowledge-Based System for Estimating Human Error Probabilities (open access)

Demonstration Integrated Knowledge-Based System for Estimating Human Error Probabilities

Human Reliability Analysis (HRA) is currently comprised of at least 40 different methods that are used to analyze, predict, and evaluate human performance in probabilistic terms. Systematic HRAs allow analysts to examine human-machine relationships, identify error-likely situations, and provide estimates of relative frequencies for human errors on critical tasks, highlighting the most beneficial areas for system improvements. Unfortunately, each of HRA's methods has a different philosophical approach, thereby producing estimates of human error probabilities (HEPs) that area better or worse match to the error likely situation of interest. Poor selection of methodology, or the improper application of techniques can produce invalid HEP estimates, where that erroneous estimation of potential human failure could have potentially severe consequences in terms of the estimated occurrence of injury, death, and/or property damage.
Date: April 21, 1999
Creator: Auflick, Jack L.
System: The UNT Digital Library
Interannual/decadal variability in MJO activity as diagnosed in the 40-year NCEP/NCAR reanalysis and simulated in an ensemble of GISST integrations (open access)

Interannual/decadal variability in MJO activity as diagnosed in the 40-year NCEP/NCAR reanalysis and simulated in an ensemble of GISST integrations

The Madden-Julian Oscillation (MJO) is the dominant mode of tropical variability at intraseasonal timescales. It displays substantial interannual variability in intensity which may have important implications for the predictability of the coupled system. The reasons for this interannual variability are not understood. The interannual behaviour of the MJO has been diagnosed initially in the 40-year NCEP/NCAR Reanalysis by calculating the variance of the 20-100 day filtered zonal mean zonal wind (10 o N-10 o S averaged) in a 100- day moving window. The results suggest that prior to the mid-1970s the activity of the MJO was consistently lower than during the latter part of the record. This may be related to either inadequacies in the data coverage, particularly over the tropical Indian Ocean prior to the introduction of satellite observations, or to the real effects of a decadal timescale warming in the tropical SSTs. This interdecadal trend is captured by the dominant EOF (explaining 28% of the variance) of the monthly mean SSTs (after removal of the mean seasonal cycle), as used in the NCEP/NCAR Reanalysis for the region of the tropics where the MJO is convectively active (i.e., 60 o E-180 o E, 20 o S-20 o N). During …
Date: April 21, 1999
Creator: Nortley, F; Rowell, D P; Slingo, J M & Sperber, K R
System: The UNT Digital Library
Real-Time Monitoring of Low-Level Mixed-Waste Loading during Polyethylene Microencapsulation using Transient Infrared Spectroscopy (open access)

Real-Time Monitoring of Low-Level Mixed-Waste Loading during Polyethylene Microencapsulation using Transient Infrared Spectroscopy

In polyethylene microencapsulation, low-level mixed waste (LLMW) is homogenized with molten polyethylene and extruded into containers, resulting in a lighter, lower-volume waste form than cementation and grout methods produce. Additionally, the polyethylene-based waste form solidifies by cooling, with no risk of the waste interfering with cure, as may occur with cementation and grout processes. We have demonstrated real-time monitoring of the polyethylene encapsulation process stream using a noncontact device based on transient infrared spectroscopy (TIRS). TIRS can acquire mid-infrared spectra from solid or viscous liquid process streams, such as the molten, waste-loaded polyethylene stream that exits the microencapsulation extruder. The waste loading in the stream was determined from the TIRS spectra using partial least squares techniques. The monitor has been demonstrated during the polyethylene microencapsulation of nitrate-salt LLMW and its surrogate, molten salt oxidation LLMW and its surrogate, and flyash. The monitor typically achieved a standard error of prediction for the waste loading of about 1% by weight with an analysis time under 1 minute.
Date: April 15, 1999
Creator: Jones, Roger W.; Kalb, Paul D.; McClelland, John F. & Ochiai, Shukichi
System: The UNT Digital Library
Strain and Texture in Al-Interconnect Wires Measured by X-Ray Microbeam Diffraction (open access)

Strain and Texture in Al-Interconnect Wires Measured by X-Ray Microbeam Diffraction

The local strain and texture in Al interconnect wires have been investigated using white and monochromatic x-ray microbeams on the MHATTCAT undulator beam line at the Advanced Photon Source. Intergrain and intragrain orientations were obtained with ~0.01 degree sensitivity using white beam measurements on wide Al pads (~100 Mu-m) and thin (2 Mu-m) Al wires. Orientation changes of up to 1 degree were found within individual grains of the (111) textured Al interconnects. Deviatoric strain measurements indicate small intragranular strain variations, but intergranular strain variations were found to be quite large.
Date: April 5, 1999
Creator: Budai, J. D.; Chung, J.-S.; Ice, G. E.; Larson, B. C.; Lowe, W. P.; Tamura, N. et al.
System: The UNT Digital Library
Remote Underwater Characterization System - Innovative Technology Summary Report (open access)

Remote Underwater Characterization System - Innovative Technology Summary Report

Characterization and inspection of water-cooled and moderated nuclear reactors and fuel storage pools requires equipment capable of operating underwater. Similarly, the deactivation and decommissioning of older nuclear facilities often requires the facility owner to accurately characterize underwater structures and equipment which may have been sitting idle for years. The Remote Underwater Characterization System (RUCS) is a small, remotely operated submersible vehicle intended to serve multiple purposes in underwater nuclear operations. It is based on the commercially-available �Scallop� vehicle 1 , but has been modified by the Department of Energy�s Robotics Technology Development Program to add auto-depth control, and vehicle orientation and depth monitoring at the operator control panel. The RUCS is designed to provide visual and gamma radiation characterization, even in confined or limited access areas. It was demonstrated in August 1998 at the Idaho National Engineering and Environmental Laboratory (INEEL) as part of the INEEL Large Scale Demonstration and Deployment Project. During the demonstration it was compared in a "head-to-head� fashion with the baseline characterization technology. This paper summarizes the results of the demonstration and lessons learned; comparing and contrasting both technologies in the areas of cost, visual characterization, radiological characterization, and overall operations.
Date: April 1, 1999
Creator: Willis, W. D.
System: The UNT Digital Library
Detection of Infrared Photons Using the Electronic Stress in Metal-Semiconductor Interfaces (open access)

Detection of Infrared Photons Using the Electronic Stress in Metal-Semiconductor Interfaces

It is well known that the work function of metals decreases when they are placed in a nonpolar liquid. A similar decrease occurs when the metal is placed into contact with a semiconductor forming a Schottky barrier. We report on a new method for detecting photons using the stress caused by photo-electrons emitted from a metal film surface in contact with a semiconductor microstructure. The photoelectrons diffuse into the microstructure and produce an electronic stress. The photon detection results from the measurement of the photo-induced bending of the microstructure. Internal photoemission has been used in the past to detect photons, however, in those cases the detection was accomplished by measuring the current due to photoelectrons and not due to electronic stress. Small changes in position (displacement) of microstructures are routinely measured in atomic force microscopy (AFM) where atomic imaging of surfaces relies on the measurement of small changes (< l0{sup -9} m) in the bending of microcantilevers. In the present work we studied the photon response of Si microcantilevers coated with a thin film of Pt. The Si microcantilevers were 500 nm thick and had a 30 nm layer of Pt. Photons with sufficient energies produce electrons from the platinum-silicon …
Date: April 5, 1999
Creator: Datskos, P. G.; Datskou, I.; Egert, C. M. & Rjic, S.
System: The UNT Digital Library