Local Integration of the National Atmospheric Release Advisory Center with Cities (LINC) (open access)

Local Integration of the National Atmospheric Release Advisory Center with Cities (LINC)

The objective of the ''Local Integration of the National Atmospheric Release Advisory Center with Cities'' (LINC) program is to demonstrate the capability for providing local government agencies with an advanced operational atmospheric plume prediction capability, which can be seamlessly integrated with appropriate federal agency support for homeland security applications. LINC is a Domestic Demonstration and Application Program (DDAP) funded by the Chemical and Biological National Security Program (CBNP), which is part of the Department of Energy's (DOE) National Nuclear Security Administration (NNSA). LINC will make use of capabilities that have been developed the CBNP, and integrated into the National Atmospheric Release Advisory Center (NARAC) at Lawrence Livermore National Laboratory (LLNL). NARAC tools services will be provided to pilot study cities and counties to map plumes from terrorism threats. Support to these local agencies will include training and customized support for exercises, special events, and general emergencies. NARAC provides tools and services that map the probable spread of hazardous material which have been accidentally or intentionally released into the atmosphere. Primarily supported by the DOE, NARAC is a national support and resource center for planning, real-time assessment and detailed studies of incidents involving a wide variety of hazards, including radiological, chemical, …
Date: March 25, 2002
Creator: Ermak, D L; Tull, J E & Mosley-Rovi, R
Object Type: Article
System: The UNT Digital Library
Temperature and Wavelength Dependent Emissivity of a Shocked Surface: A First Experiment (open access)

Temperature and Wavelength Dependent Emissivity of a Shocked Surface: A First Experiment

We have conducted an experiment in which the temperature and the wavelength dependent emissivity of a shocked surface has been measured. In the past, only the thermal emission from the shocked surface has been measured. The lack of knowledge of the emissivity as a function of wavelength leads to uncertainty in converting the measured emission spectrum into a surface temperature. We have developed a technique by which we are able to calculate both the emissivity of the shocked surface over a range of relevant wavelengths and the temperature of the surface. We use a multi-channel spectrometer in combination with a pulsed light source having a known spectrum of infrared radiation. Two separate techniques using a pulse of reflected radiation are employed and described. Both give the same result: An initially polished molybdenum surface that is shocked and partially released has a temperature of 1040 degrees Kelvin and a wavelength ({lambda}) dependent emissivity of 0.16 ({lambda}=1.2{micro}m), 0.10 ({lambda} =1.6 {micro}m), and 0.20 ({lambda} =2.3 {micro}m).
Date: January 25, 2002
Creator: Poulsen, P & Hare, D E
Object Type: Article
System: The UNT Digital Library
National Ignition Facility Cryogenic Target Systems Interim Management Plan (open access)

National Ignition Facility Cryogenic Target Systems Interim Management Plan

Restricted availability of funding has had an adverse impact, unforeseen at the time of the original decision to projectize the National Ignition Facility (NIF) Cryogenic Target Handling Systems (NCTS) Program, on the planning and initiation of these efforts. The purpose of this document is to provide an interim project management plan describing the organizational structure and management processes currently in place for NCTS. Preparation of a Program Execution Plan (PEP) for NCTS has been initiated, and a current draft is provided as Attachment 1 to this document. The National Ignition Facility is a multi-megajoule laser facility being constructed at Lawrence Livermore National Laboratory (LLNL) by the National Nuclear Security Administration (NNSA) in the Department of Energy (DOE). Its primary mission is to support the Stockpile Stewardship Program (SSP) by performing experiments studying weapons physics, including fusion ignition. NIF also supports the missions of weapons effects, inertial fusion energy, and basic science in high-energy-density physics. NIF will be operated by LLNL under contract to the University of California (UC) as a national user facility. NIF is a low-hazard, radiological facility, and its operation will meet all applicable federal, state, and local Environmental Safety & Health (ES&H) requirements. The NCTS Interim Management …
Date: April 25, 2002
Creator: Warner, B
Object Type: Report
System: The UNT Digital Library
Micro Benchmarking, Performance Assertions and Sensitivity Analysis: A Technique for Developing Adaptive Grid Applications (open access)

Micro Benchmarking, Performance Assertions and Sensitivity Analysis: A Technique for Developing Adaptive Grid Applications

This study presents a technique that can significantly improve the performance of a distributed application by allowing the application to locally adapt to architectural characteristics of distinct resources in a distributed system. Application performance is sensitive to application parameter--system architecture pairings. In a distributed or Grid enabled applciation, a single parameter configuration for the whole application will not always be optimal for every participating resource. In particular, some configurations can significantly degrade performance. Furthermore, the behavior of a system may change during the course of the run. The technique described here provides an automated mechanism for run-time adaptation of application parameters to the local system architecture. Using a simulation of a Monte Carlo physics code, the authors demonstrate that this technique can achieve speedups of 18%-37% on individual resources in a distributed environment.
Date: February 25, 2002
Creator: Corey, I R; Johnson, J R & Vetter, J S
Object Type: Article
System: The UNT Digital Library
Summary of the Hanford Site Environmental Report for Calendar Year 2001 (open access)

Summary of the Hanford Site Environmental Report for Calendar Year 2001

This booklet summarizes the Hanford Site Environmental Report for Calendar Year 2001. The report includes information and summary data that describe environmental management performance at the site, demonstrate the status of the site's compliance with applicable federal, state, and local environmental laws and regulations, and highlight significant environmental monitoring and surveillance programs and efforts. The document is written to meet requirements and guidelines of the U.S. Department of Energy (DOE) and the needs of the public.
Date: September 25, 2002
Creator: Hanf, Robert W.; O'Connor, Georganne P. & Poston, Ted M.
Object Type: Report
System: The UNT Digital Library
Primary Polymer Aging Processes Identified from Weapon Headspace Chemicals (open access)

Primary Polymer Aging Processes Identified from Weapon Headspace Chemicals

A current focus of our weapon headspace sampling work is the interpretation of the volatile chemical signatures that we are collecting. To help validate our interpretation we have been developing a laboratory-based material aging capability to simulate material decomposition chemistries identified. Key to establishing this capability has been the development of an automated approach to process, analyze, and quantify arrays of material combinations as a function of time and temperature. Our initial approach involves monitoring the formation and migration of volatile compounds produced when a material decomposes. This approach is advantageous in that it is nondestructive and provides a direct comparison with our weapon headspace surveillance initiative. Nevertheless, this approach requires us to identify volatile material residue and decomposition byproducts that are not typically monitored and reported in material aging studies. Similar to our weapon monitoring method, our principle laboratory-based method involves static headspace collection by solid phase microextraction (SPME) followed by gas chromatography/mass spectrometry (GC/MS). SPME is a sorbent collection technique that is ideally suited for preconcentration and delivery of trace gas-phase compounds for analysis by GC. When combined with MS, detection limits are routinely in the low- and sub-ppb ranges, even for semivolatile and polar compounds. To automate …
Date: March 25, 2002
Creator: Chambers, D M; Bazan, J M & Ithaca, J G
Object Type: Article
System: The UNT Digital Library
National NIF Diagnostic Program Interim Management Plan (open access)

National NIF Diagnostic Program Interim Management Plan

The National Ignition Facility (NIF) has the mission of supporting Stockpile Stewardship and Basic Science research in high-energy-density plasmas. To execute those missions, the facility must provide diagnostic instrumentation capable of observing and resolving in time events and radiation emissions characteristic of the plasmas of interest. The diagnostic instrumentation must conform to high standards of operability and reliability within the NIF environment. These exacting standards, together with the facility mission of supporting a diverse user base, has led to the need for a central organization charged with delivering diagnostic capability to the NIF. The National NIF Diagnostics Program (NNDP) has been set up under the aegis of the NIF Director to provide that organization authority and accountability to the wide user community for NIF. The funds necessary to perform the work of developing diagnostics for NIF will be allocated from the National NIF Diagnostics Program to the participating laboratories and organizations. The participating laboratories and organizations will design, build, and commission the diagnostics for NIF. Restricted availability of funding has had an adverse impact, unforeseen at the time of the original decision to projectize NIF Core Diagnostics Systems and Cryogenic Target Handing Systems, on the planning and initiation of these …
Date: April 25, 2002
Creator: Warner, B
Object Type: Report
System: The UNT Digital Library
Development of a Detonation Profile Test for Studying Aging Effects in LX-17 (open access)

Development of a Detonation Profile Test for Studying Aging Effects in LX-17

A new small-scale Detonation Profile Test (DPT) is being developed to investigate aging effects on the detonation behavior of insensitive high explosives. The experiment involves initiating a small LX-17 cylindrical charge (12.7-19.1 mm diameter x 25.4-33 mm long) and measuring the velocity and curvature of the emerging detonation wave using a streak camera. Results for 12.7 mm diameter unconfined LX-17 charges show detonation velocity in the range between 6.79 and 7.06 km/s for parts up to 33 mm long. Since LX-17 can not sustain detonation at less than 7.3 km/s, these waves were definitely failing. Experiments with confined 12.7 mm diameter and unconfined 19.1 mm diameter samples showed wave velocities in the range of 7.4-7.6 km/s, values approaching steady state conditions at infinite diameter. Experiments with unconfined 19.1 mm diameter specimens are expected to provide reproducible and useful range of detonation parameters suitable for studying aging effects.
Date: March 25, 2002
Creator: Tran, T.; Lewis, P.; Tarver, Craig M.; Maienschein, J.; Druce, R.; Lee, R. et al.
Object Type: Article
System: The UNT Digital Library
Propogation of the 1(mu) High-Power Beam from a Solid-State Heat-Capacity Laser (open access)

Propogation of the 1(mu) High-Power Beam from a Solid-State Heat-Capacity Laser

A solid-state laser system, used as a directed energy defensive weapon, possesses many compelling logistical advantages over high-average-power chemical laser systems. As an electrically-powered laser, it uses no chemicals, generates no effluents, and requires no specialized logistics support--the laser is recharged by running the vehicle engine. It provides stealth, having low signature operation without the generation of temperature, smoke, or visible light. It is silent in operation, limited only by the onboard vehicle electrical charging and propulsion system. Using the heat-capacity mode of operation, scaling of average power from a solid-state laser has been demonstrated beyond 10kW and work in progress will result in the demonstration of a 100 kW solid-state heat-capacity laser (SSHCL). The heat-capacity approach provides unprecedented power-to-weight ratios in a compact platform that is readily adapted to mobile operation. A conceptual engineering and packaging study has resulted in a 100kW SSHCL design that we believe can be integrated onto a hybrid-electric HMMWV or onto new vehicle designs emerging from the future combat system (FCS) development. 100 kW has been proposed as a power level that demonstrates a significant scaling beyond what has been demonstrated for a solid-state laser system and which could have a significant lethality against …
Date: June 25, 2002
Creator: Dane, C B; Moriss, J R; Rubenchik, A M & Boley, C D
Object Type: Report
System: The UNT Digital Library
Femtosecond Laser Interaction with Energetic Materials (open access)

Femtosecond Laser Interaction with Energetic Materials

Femtosecond laser ablation shows promise in machining energetic materials into desired shapes with minimal thermal and mechanical effects to the remaining material. We will discuss the physical effects associated with machining energetic materials and assemblies containing energetic materials, based on experimental results. Interaction of ultra-short laser pulses with matter will produce high temperature plasma at high-pressure which results in the ablation of material. In the case of energetic material, which includes high explosives, propellants and pyrotechnics, this ablation process must be accomplished without coupling energy into the energetic material. Experiments were conducted in order to characterize and better understand the phenomena of femtosecond laser pulse ablation on a variety of explosives and propellants. Experimental data will be presented for laser fluence thresholds, machining rates, cutting depths and surface quality of the cuts.
Date: March 25, 2002
Creator: Roos, E; Benterou, J; Lee, R; Roeske, F & Stuart, B
Object Type: Article
System: The UNT Digital Library
Fabrication of Luminescent Nanostructures by Dip-Pen Nanolithography (open access)

Fabrication of Luminescent Nanostructures by Dip-Pen Nanolithography

We used a combination of dip-pen nanolithography and scanning optical confocal microscopy to fabricate and visualize luminescent nanoscale patterns of various materials on glass substrates. We show that this method can be used successfully to push the limits of dip-pen nanolithography down to controlled deposition of single molecules. We also demonstrate that this method is able to create and visualize protein patterns on surfaces. Finally, we show that our method can be used to fabricate polymer nanowires of controlled size using conductive polymers. We also present a kinetic model that accurately describes the deposition process.
Date: June 25, 2002
Creator: Noy, A; Miller, A E; Klare, J E; Weeks, B L; Woods, B W & DeYoreo, J J
Object Type: Article
System: The UNT Digital Library
Feasibility of Using 36 C1 to Depict Water Infiltration at the Pit 7 Complex, LLNL Site 300 (open access)

Feasibility of Using 36 C1 to Depict Water Infiltration at the Pit 7 Complex, LLNL Site 300

Measurements of bomb-pulse {sup 36}Cl and chloride concentrations in soils from the Pit 7 Complex basin, LLNL Site 300, combined with a demonstration model of moisture flux and infiltration rate, indicate that the bomb-pulse can be an extremely useful tool for the characterization of the unsaturated hydrology at Site 300. Bomb-pulse {sup 36}Cl is readily identifiable in the soil column, and exhibits moisture infiltration-related variations at different locations. It can be used to calibrate chloride accumulation models of unsaturated flow. In the continuing investigation of the origin and development of the Pit 7 Complex tritium plume, bomb-pulse {sup 36}Cl will provide a useful mechanism for hydrologic characterization.
Date: January 25, 2002
Creator: Nimz, G J
Object Type: Report
System: The UNT Digital Library
Report on Transport and Loading of Explosives in the Femtosecond Tank, Room 1711A HEAF 00-010 (open access)

Report on Transport and Loading of Explosives in the Femtosecond Tank, Room 1711A HEAF 00-010

The current OSP associated with Room 1711A located in Building 191 (HEAF) sets a limit of 5 grams Net Explosive Weight (NEW) of explosives for the room. A question was raised as to the capability of that room to withstand the overpressure created by a detonation of 5 grams NEW of explosives. Calculations were inconclusive, but indicated the wallboard would not remain intact if there was a detonation of 5 grams NEW at a distance of eight feet from the wall. These calculations did not seem logical. To verify the hypothesis, a series of experiments were conducted in the 1 Kilogram tank. The experiments consisted of exposing a pre-built double-sided wall with the same stud spacing and drywall thickness found in the walls of Room 1711A to various amounts of explosives to create expected overpressures. The objective of this test was to prove or disprove that the walls in room 1711A could withstand a detonation of 5 grams of high explosives and to determine if larger quantities of explosives could be worked on in the room while still providing the required level of protection for personnel outside the room. Testing has verified that not only can the walls withstand a …
Date: April 25, 2002
Creator: Hill, D L
Object Type: Report
System: The UNT Digital Library
Thermal Decomposition of New and Aged LX-04 and PBX 9501 (open access)

Thermal Decomposition of New and Aged LX-04 and PBX 9501

One-Dimensional-Time-To-Explosion (ODTX) experiments were conducted to study the thermal decomposition of aged LX-04, aged PBX 9501, HMX class 1 and class 2, Estane and Estane/BDNPA-F (PBX 950 1 plasticized-binder) materials. The tests involved heating 12.7 mm diameter spherical samples in pre-heated aluminum anvils until explosion. The times to explosion at different heating temperatures were compared to historical data on new LX-04 and PBX 9501 compounds to study any changes to their thermal stability. New and aged LX-04 showed comparable decomposition kinetics. The data for aged PBX 9501 showed slightly longer explosion times at equivalent temperatures. Analysis of the error in time measurement is limited and complicated by several experimental factors but the small time change appears to be experimentally significant. The thermal decomposition of these PBXs were modeled using a coupled thermal and heat transport code (chemical TOPAZ) using separate kinetics for HMX and binder decomposition. Separate decomposition models were developed for HMX and the reactive PBX 9501 binder component (1:1 Estane:BDNPA/F) based on the measured explosion times. Thermal aging models can describe longer explosion times by the loss of plasticizer-binder constituent which was more thermally reactive.
Date: March 25, 2002
Creator: Tran, T. D.; Tarver, Craig M. & Idar, D. J.
Object Type: Article
System: The UNT Digital Library
Multi-Resolution Modeling of Large Scale Scientific Simulation Data (open access)

Multi-Resolution Modeling of Large Scale Scientific Simulation Data

Data produced by large scale scientific simulations, experiments, and observations can easily reach tera-bytes in size. The ability to examine data-sets of this magnitude, even in moderate detail, is problematic at best. Generally this scientific data consists of multivariate field quantities with complex inter-variable correlations and spatial-temporal structure. To provide scientists and engineers with the ability to explore and analyze such data sets we are using a twofold approach. First, we model the data with the objective of creating a compressed yet manageable representation. Second, with that compressed representation, we provide the user with the ability to query the resulting approximation to obtain approximate yet sufficient answers; a process called adhoc querying. This paper is concerned with a wavelet modeling technique that seeks to capture the important physical characteristics of the target scientific data. Our approach is driven by the compression, which is necessary for viable throughput, along with the end user requirements from the discovery process. Our work contrasts existing research which applies wavelets to range querying, change detection, and clustering problems by working directly with a decomposition of the data. The difference in this procedures is due primarily to the nature of the data and the requirements of …
Date: February 25, 2002
Creator: Baldwin, Chuck; Abdulla, Ghaleb & Critchlow, Terence
Object Type: Article
System: The UNT Digital Library
Aerodynamic Design of Heavy Vehicles Reporting Period September 2001 through January 15, 2002 (open access)

Aerodynamic Design of Heavy Vehicles Reporting Period September 2001 through January 15, 2002

Activities for this first quarter include continued effort in simulating the experiments performed in the NASA 7-ft x 10-ft wind tunnel with the GTS geometry using both LLNL's advanced computational tools and NASA's Overflow code. Along with this analysis effort, we continue to implement advanced algorithms in LLNL's models to improve simulation speed and accuracy and to verify and validate these advanced simulation tools.
Date: January 25, 2002
Creator: McCallen, R.; Salari, K.; Ortega, J.; Yen-Nakafuji, D.; Dunn, T.; Browand, F. et al.
Object Type: Report
System: The UNT Digital Library
Properties and Applications of Laser Generated X-Ray Sources (open access)

Properties and Applications of Laser Generated X-Ray Sources

The rapid development of laser technology and related progress in research using lasers is shifting the boundaries where laser based sources are preferred over other light sources particularly in the XUV and x-ray spectral region. Laser based sources have exceptional capability for short pulse and high brightness and with improvements in high repetition rate pulsed operation, such sources are also becoming more interesting for their average power capability. This study presents an evaluation of the current capabilities and near term future potential of laser based light sources and summarizes, for the purpose of comparison, the characteristics and near term prospects of sources based on synchrotron radiation and free electron lasers. Conclusions are drawn on areas where the development of laser based sources is most promising and competitive in terms of applications potential.
Date: February 25, 2002
Creator: Smith, R F & Key, M H
Object Type: Article
System: The UNT Digital Library
WSSX - A Joint U.S.-Russian Nuclear Counter-Terrorism Exchange (open access)

WSSX - A Joint U.S.-Russian Nuclear Counter-Terrorism Exchange

In 1994, the U. S. and Russian Federation governments formally agreed to exchange information on the safety and security of nuclear weapons. This agreement included three major elements, called Technical Working Groups (TWGs). TWG C deals with counter-terrorism. Its four assigned actions and U.S./Russian experience are reviewed in this paper. Although active exchange programs were created under TWGs A and B, involving workshops and laboratory-to-laboratory development projects, little work was initiated in TWG C, due to the sensitive nature of this information. After 9/11, however, it became clear that much could be gained by having each country share information to help solve the problem of nuclear proliferation among terrorist groups. Government-to-government meetings have reaffirmed the initial agreement to exchange information on this topic, and a number of joint project proposals are now under discussion. The Joint Steering Committee that oversees this exchange has approved approximately 20 projects. They include such topics as terrorist threat scenario development, detection of nuclear material and explosives in transportation containers, analysis of material mass and configuration, and consequence mitigation. It is expected that the joint development of these capabilities will enhance our ability to respond to a nuclear threat and to facilitate mutual assistance, should …
Date: September 25, 2002
Creator: Crites, T. R.
Object Type: Article
System: The UNT Digital Library
RCRA Groundwater Quality Assessment Report for Single-Shell Tank Waste Management Area T (January 1998 through December 2001) (open access)

RCRA Groundwater Quality Assessment Report for Single-Shell Tank Waste Management Area T (January 1998 through December 2001)

This report presents the findings of continued groundwater quality assessment at Waste Management Area T in the 200 West Area of the Hanford Site. It covers January 1988 through December 2001.
Date: July 25, 2002
Creator: Horton, Duane G.; Hodges, Floyd N.; Johnson, V. G. & Chou, Charissa J.
Object Type: Report
System: The UNT Digital Library
Science & Technology Review November 2002 (open access)

Science & Technology Review November 2002

This months issue of Science and Technology Review has the following articles: (1) High-Tech Help for Fighting Wildfires--Commentary by Leland W. Younker; (2) This Model Can Take the Heat--A physics-based simulation program to combat wildfires combines the capabilities and resources of Lawrence Livermore and Los Alamos national laboratories. (3) The Best and the Brightest Come to Livermore--The Lawrence Fellowship Program attracts the most sought-after postdoctoral researchers to the Laboratory. (4) A view to Kill--Livermore sensors are aimed at the ''kill'' vehicle when it intercepts an incoming ballistic missile. (5) 50th Anniversary Highlight--Biological Research Evolves at Livermore--Livermore's biological research program keeps pace with emerging national issues, from studying the effects of ionizing radiation to detecting agents of biological warfare.
Date: September 25, 2002
Creator: Budil, K
Object Type: Journal/Magazine/Newsletter
System: The UNT Digital Library
Focal Length Measurements for the National Ignition Facility Large Lenses (open access)

Focal Length Measurements for the National Ignition Facility Large Lenses

The focal length of the spatial filter and final focus lenses for the National Ignition Facility are measured to < {+-} 0.01% using a combination of master lenses and production-oriented techniques for relative focal length.
Date: January 25, 2002
Creator: Parham, T G; McCarville, T J; Johnson, M A & Kiikka, C
Object Type: Article
System: The UNT Digital Library
An Electronic Flash Lamp System to Replace the Traditional, Explosively-Driven Light Source (open access)

An Electronic Flash Lamp System to Replace the Traditional, Explosively-Driven Light Source

Electronic flash lamps are being developed at the Lawrence Livermore National Laboratory (LLNL). These lamps are intended to replace the traditional explosively driven Argon-gas filled light sources (Argon candles) that are currently used to provide illumination for high speed rotating mirror-framing cameras. At Livermore, we are developing an electronic flash lamp system that can match or exceed the light output of a traditional Argon candle. These systems utilize a Plasma Arc Lamp developed by PRISM Science Inc of Chatham, MA, USA. In the past, high-speed photography requiring explosively driven light sources were a one-time-only event that destroyed fixtures and optical alignment. The electronic flash lamp system, utilizing the Plasma Arc Lamp, will replace the explosively driven lighting systems and provide the capability to dry run experimental setups and repeat tests without damage to the experimental set-up. The electronic flash lamp system eliminates the problem of collateral damage to the experiment and does not add to the overall amount of explosives needed for a single test. Since the Pulsed-Power driver is remotely located, only the flash lamp itself is destroyed when the explosive shot is fired. The flexible geometry of this light source also enables the user to create complex light …
Date: September 25, 2002
Creator: Stigman, W L; Kihara, R & Scarpetti, R D
Object Type: Article
System: The UNT Digital Library
Analysis of Induced Gas Releases During Retrieval of Hanford Double-Shell Tank Waste (open access)

Analysis of Induced Gas Releases During Retrieval of Hanford Double-Shell Tank Waste

Radioactive waste is scheduled to be retrieved from Hanford double-shell tanks AN-103, AN-104, AN-105, and AW-101 to the vitrification plant beginning about 2009. Retrieval may involve decanting the supernatant liquid and/or mixing the waste with jet pumps. In these four tanks, which contain relatively large volumes of retained gas, both of these operations are expected to induce buoyant displacement gas releases that can potentially raise the tank headspace hydrogen concentration to very near the lower flammability limit. This report describes the theory and detailed physical models for both the supernatant decant and jet mixing processes and presents the results from applying the models to these operations in the four tanks. The technical bases for input parameter distributions are elucidated.
Date: September 25, 2002
Creator: Wells, Beric E.; Cuta, Judith M.; Hartley, Stacey A.; Mahoney, Lenna A.; Meyer, Perry A. & Stewart, Charles W.
Object Type: Report
System: The UNT Digital Library
Edge-Spread Functions Expected for Several Changes in a Commercial Flat-Panel System (open access)

Edge-Spread Functions Expected for Several Changes in a Commercial Flat-Panel System

The Bldg. 239 radiography facility uses a 9 MeV bremsstrahlung linac and a commercially available fiat-panel detector system. Ref. [1] discusses the facility in detail. Ref. [1] furthermore discusses the imaging quality of the fiat-panel system, and identifies several sources of image blur for the system in question. The maim'' contributors to the imaging blur are radiation scattered from the front cover of the detector housing, radiation scattered from the back cover of the detector housing, and radiation scattered from the aluminum plate that supports the amorphous-Si detector within the detector housing. The manufacturer of one such fiat-panel system seems willing to modify one of their products as requested, if such modifications may be made easily. Easy modifications would include making the detector housing thinner, decreasing the sizes of air gaps inside tile detector system, etc. Removing the aluminum support plate is considered to be a difficult modification. This memo reports the results of a set of Monte Carlo simulations that were performed to predict the changes in imaging quality, compared to that of the current system, if the detector is modified as suggested above. In particular, the edge-spread function (ESF) was calculated for each modification. ESFs were calculated for …
Date: February 25, 2002
Creator: Schach von Wittenau, A. E.
Object Type: Report
System: The UNT Digital Library