A novel condenser for EUV lithography ring-field projection optics (open access)

A novel condenser for EUV lithography ring-field projection optics

A condenser for a ring-field extreme ultra-violet (EUV) projection lithography camera is presented. The condenser consists of a gently undulating mirror, that we refer to as a ripple plate, and which is illuminated by a collimated beam at grazing incidence. The light is incident along the ripples rather than across them, so that the incident beam is reflected onto a cone and subsequently focused on to the arc of the ring field. A quasistationary illumination is achieved, since any one field point receives light from points on the ripples, which are distributed throughout the condenser pupil. The design concept can easily be applied to illuminate projection cameras with various ring-field and numerical aperture specifications. Ray-tracing results are presented of a condenser for a 0.25 NA EUV projection camera.
Date: July 15, 1999
Creator: Chapman, H. & Nugent, K. A.
Object Type: Article
System: The UNT Digital Library
A Correlated Study of the Response of a Satellite to Acoustic Radiation Using Statistical Energy Analysis and Acoustic Test Data (open access)

A Correlated Study of the Response of a Satellite to Acoustic Radiation Using Statistical Energy Analysis and Acoustic Test Data

Aerospace payloads, such as satellites, are subjected to vibroacoustic excitation during launch. Sandia's MTI satellite has recently been certified to this environment using a combination of base input random vibration and reverberant acoustic noise. The initial choices for the acoustic and random vibration test specifications were obtained from the launch vehicle Interface Control Document (ICD). In order to tailor the random vibration levels for the laboratory certification testing, it was necessary to determine whether vibration energy was flowing across the launch vehicle interface from the satellite to the launch vehicle or the other direction. For frequencies below 120 Hz this issue was addressed using response limiting techniques based on results from the Coupled Loads Analysis (CLA). However, since the CLA Finite Element Analysis FEA model was only correlated for frequencies below 120 Hz, Statistical Energy Analysis (SEA) was considered to be a better choice for predicting the direction of the energy flow for frequencies above 120 Hz. The existing SEA model of the launch vehicle had been developed using the VibroAcoustic Payload Environment Prediction System (VAPEPS) computer code [1]. Therefore, the satellite would have to be modeled using VAPEPS as well. As is the case for any computational model, the …
Date: November 15, 1999
Creator: Cap, Jerome S. & Tracey, Brian
Object Type: Article
System: The UNT Digital Library
Thermal and Fluid Flow Brazing Simulations (open access)

Thermal and Fluid Flow Brazing Simulations

The thermal response of fixtured parts in a batch-type brazing furnace can require numerous, time-consuming development runs before an acceptable furnace schedule or joint design is established. Powerful computational simulation tools are being developed to minimize the required number of verification experiments, improve furnace throughput, and increase product yields. Typical furnace simulations are based on thermal, fluid flow, and structural codes that incorporate the fundamental physics of the brazing process. The use of massively parallel computing to predict furnace and joint-level responses is presented. Measured and computed data are compared. Temperature values are within 1-270 of the expected peak brazing temperature for different loading conditions. Sensitivity studies reveal that the thermal response is more sensitive to the thermal boundary conditions of the heating enclosure than variability y in the materials data. Braze flow simulations predict fillet geometry and free surface joint defects. Dynamic wetting conditions, interfacial reactions, and solidification structure add a high degree of uncertainty to the flow results.
Date: December 15, 1999
Creator: Hosking, Floyd Michael; Gianolakis, Steven E.; Givler, Richard C. & Schunk, P. Randall
Object Type: Article
System: The UNT Digital Library
Iodine-129 Dose in LLW Disposal Facility Performance Assessments (open access)

Iodine-129 Dose in LLW Disposal Facility Performance Assessments

Iodine-129 has the lowest Performance Assessment derived inventory limit in SRS disposal facilities. Because iodine is concentrated in the body to one organ, the thyroid, it has been thought that dilution with stable iodine would reduce the dose effects of 129I.Examination of the dose model used to establish the Dose conversion factor for 129I shows that, at the levels considered in performance assessments of low-level waste disposal facilities, the calculated 129I dose already accounts for ingestion of stable iodine. At higher than normal iodine ingestion rates, the uptake of iodine by the thyroid itself decrease, which effectively cancels out the isotopic dilution effect.
Date: October 15, 1999
Creator: Wilhite, E.L.
Object Type: Report
System: The UNT Digital Library
Comparison of the crevice corrosion resistance of alloys 625 and 22 (open access)

Comparison of the crevice corrosion resistance of alloys 625 and 22

The Yucca Mountain Site Characterization Project is concerned with the corrosion resistance of candidate engineered waste package materials. A variety of waste package designs have been proposed for US and Canadian High Level Nuclear Waste Repositories. A common feature of each design is the possibility of utilizing a corrosion resistant material such as a nickel-based super alloy or titanium-based alloy. A suitable corrosion resistant material may provide (a) kinetic immunity if the combination of repository environmental conditions and alloy resistance assure both: (i) a passive condition with negligible chance of localized corrosion stabilization, as well as (ii) low enough passive dissolution rates to insure conventional corrosion allowance over geological times, (b) a second form of ''corrosion allowance,'' if it can be scientifically demonstrated that a mechanism for stifling (i.e., death) of localized corrosion propagation occurs well before waste canisters are penetrated, or (c) such a low probability of initiation and continued propagation that a tolerably low degree of penetration occurs. Unfortunately, a large database on the crevice corrosion properties of alloy 22 does not exist in comparison to alloy 625. Alloy screening tests in oxidizing acids containing FeCl3 indicate that alloy 22 is more resistant to crevice corrosion than 625 …
Date: September 15, 1999
Creator: Palmer, J.; Kehler, B.; Iloybare, G. O. & Scully, J. R.
Object Type: Article
System: The UNT Digital Library
Tritium Loading of Pinellas U-Bed No. 874 (open access)

Tritium Loading of Pinellas U-Bed No. 874

The DOE-Richland Office has requested WSRC to supply PNNL with a Pinellas U-bed loaded with tritium for permeation experiments. It is desired to have less than 1000 Ci tritium in the bed to allow shipping without excessive packaging requirements. Pinellas U-Bed No. 874 was loaded with approximately 955 Ci of 98 percent purity tritium on the ETM manifold in the Materials Test Facility in Building 232-H.
Date: September 15, 1999
Creator: Shanahan, K. L.
Object Type: Report
System: The UNT Digital Library
Precise tests of x-ray scattering theories in the Compton regime. (open access)

Precise tests of x-ray scattering theories in the Compton regime.

The authors report two experiments intended to test the accuracy of state-of-the-art theoretical predictions for x-ray scattering from low-Z atoms. The first one deals with the differential x-ray scattering cross sections in Ne and He from 11-22 keV and the Ne Compton-to-Rayleigh scattering ratio in this energy range. It was found that, in order to be consistent with the experimental results, an accurate description at low Z must include nonlocal exchange, electron correlation, and dynamic effects. The second experiment concerns the ratio of helium double-to-single ionization for Compton scattering in the 8-28 keV energy range where published experimental and theoretical results so far fail to give a consistent picture. The progress of the experiment and the data analysis is reported.
Date: January 15, 1999
Creator: Dunford, R. W.; Gemmell, D. S.; Kanter, E. P.; Krassig, B.; Southworth, S. H. & Young, L.
Object Type: Article
System: The UNT Digital Library
Evaluation and Demonstration of the BNFL Ionsens (open access)

Evaluation and Demonstration of the BNFL Ionsens

This report describes the technology, system, and process that has been developed and tested. It also discusses the technology''s advantages, disadvantages, system performance, and its effectiveness. A comparison to the baseline technologies as well as other competing technologies will be presented. This report will include a brief discussion of commercial availability and technology readiness for implementation and recommendations for its use.
Date: October 15, 1999
Creator: Salaymeh, S.R.
Object Type: Report
System: The UNT Digital Library
Weak matrix elements in the large N{sub c} limit (open access)

Weak matrix elements in the large N{sub c} limit

The matrix elements of the four quark operators needed to predict many weak interaction processes can be evaluated using the large N{sub c} limit of quantum chromodynamics. At leading order in the large N{sub c} expansion, the weak matrix elements of four quark operators factorize into independent matrix elements of two quark operators, a common approximation being used today. At the next leading order, the weak matrix elements acquire the leading scale and scheme dependence expected for these matrix elements in full QCD. They discuss methods to evaluate these matrix elements which involve matching perturbative QCD calculations at short distance to non-perturbative hadronic matrix elements at long distance.
Date: October 15, 1999
Creator: Bardeen, William A.
Object Type: Article
System: The UNT Digital Library
A Hybrid Hydrologic-Geophysical Inverse Technique for the Assessment and Monitoring of Leachates in the Vadose Zone (open access)

A Hybrid Hydrologic-Geophysical Inverse Technique for the Assessment and Monitoring of Leachates in the Vadose Zone

The objective of this study is to develop and field test a new, integrated Hybrid Hydrologic-Geophysical Inverse Technique (HHGIT) for characterization of the vadose zone at contaminated sites. This new approach to site characterization and monitoring can provide detailed maps of hydrogeological heterogeneity and the extent of contamination by combining information from 3D electric resistivity tomography (ERT) and/or 2D cross borehole ground penetrating radar (XBGPR) surveys, statistical information about heterogeneity and hydrologic processes, and sparse hydrologic data. Because the electrical conductivity and dielectric constant of the vadose zone (from the ERT and XBGPR measurements, respectively) can be correlated to the fluid saturation and/or contaminant concentration, the hydrologic and geophysical measurements are related.
Date: June 15, 1999
Creator: Alumbaugh, David L.; Yeh, Jim; Labrecque, Doug; Glass, Robert J.; Brainard, James & Rautman, Chris
Object Type: Report
System: The UNT Digital Library
Early Inflation and Cosmology in Theories with Sub-Millimeter Dimensions (open access)

Early Inflation and Cosmology in Theories with Sub-Millimeter Dimensions

We discuss early cosmology in theories where the fundamental Planck mass is close to the TeV scale. In such theories the standard model fields are localized to a (3 + 1)-dimensional wall with n new transverse sub-millimeter sized spatial dimensions. The topics touched upon include: early inflation that occurs while the size of the new dimensions are still small, the spectrum and magnitude of density perturbations, the post-inflation era of contraction of our world while the internal dimensions evolve to their final ''large'' radius, and the production of gravitons in the bulk during these two eras. The radion moduli problem is also discussed.
Date: March 15, 1999
Creator: Arkani-Hamed, Nima
Object Type: Report
System: The UNT Digital Library
Evaluation of H2 Getter Materials for Use in the TRUPACT-II (open access)

Evaluation of H2 Getter Materials for Use in the TRUPACT-II

Savannah River Site (SRS) has many waste drums containing Pu-238 that exceed the currently allowed wattage for transportation in the Transuranic Package Transporter-II (TRUPACT-II). By eliminating layers of confinement in waste drums and using getters to remove hydrogen gas, the TRUPACT-II waste loading can be increased significantly, with the potential of reaching the package''s 40-watt thermal limit. The cost savings associated with increasing the waste loading are enormous, and can be measured by reduced numbers of shipments, required processing facilities, and years of effort. To support the decision-making process and provide a good starting point for future development efforts at SRTC, the design requirements for a getter system to be used in the TRUPACT-II were compiled and are discussed in detail in the Appendix.
Date: November 15, 1999
Creator: Livingston, R. R.
Object Type: Report
System: The UNT Digital Library
Probing excited states in nuclei at and beyond the proton dripline. (open access)

Probing excited states in nuclei at and beyond the proton dripline.

The coupling of a Compton-suppressed Ge (CSGe) detector array to a recoil separator has seen limited use in the past due to the low efficiency for measuring recoil--{gamma} ray coincidences (< 0.1%). With the building of new generation recoil separators and gamma-ray arrays, a substantial increase in detection efficiency has been achieved. This allows for the opportunity to measure excited states in nuclei with cross-sections below 100 nb. In this paper, results from the coupling of a modest array of CSGe detectors (AYE-Ball) and a current generation Ge array (Gammasphere) with a recoil separator (FMA) will be presented.
Date: March 15, 1999
Creator: Carpenter, M. P.
Object Type: Article
System: The UNT Digital Library
Microstructure and Performance of Kovar/Alumina Joints Made with Silver-Copper Base Active Metal Braze Alloys (open access)

Microstructure and Performance of Kovar/Alumina Joints Made with Silver-Copper Base Active Metal Braze Alloys

Poor hermeticity performance was observed for Al{sub 2}O{sub 3}-Al{sub 2}O{sub 3} ceramic-ceramic joints having a Kovar{trademark} alloy interlayer. The active Ag-Cu-Ti filler metal was used to braze the substrates together. The Ti active element was scavenged from the filler metal by the formation of a (Fe, Ni, Co){sub x}Ti phase (x= 2-3) that prevented development of a continuous Ti{sub x}O{sub y} layer at the filler metal/Al{sub 2}O{sub 3} interface. Altering the process parameters did not circumvent the scavenging of Ti. Molybdenum barrier layers 1000, 2500, or 5000 {angstrom} thick on the Kovar{trademark} surfaces successfully allowed Ti{sub x}O{sub y} formation at the filler metal/Al{sub 2}O{sub 3} interface and hermetic joints. The problems with the Ag-Cu-Ti filler metal for Kovar{trademark}/Al{sub 2}O{sub 3} braze joints led to the evaluation of a Ag-Cu-Zr filler metal. The Zr (active element) in Ag-Cu-Zr filler metal was not susceptible to the scavenging problem.
Date: December 15, 1999
Creator: STEPHENS, JOHN J.; VIANCO,PAUL T.; HLAVA,PAUL F. & WALKER,CHARLES A.
Object Type: Article
System: The UNT Digital Library
Comparison of the Bioavailability of Waste Laden Soils Using ''In Vivo'' ''In Vitro'' Analytical Methodology and Bioaccessibility of Radionuclides for Refinement of Exposure/Dose Estimates (open access)

Comparison of the Bioavailability of Waste Laden Soils Using ''In Vivo'' ''In Vitro'' Analytical Methodology and Bioaccessibility of Radionuclides for Refinement of Exposure/Dose Estimates

The bioavailability of soil contaminants can be measured using in vitro or in vivo techniques. Since there was no standard method for intercomparison among laboratories, we compared two techniques for bioavailability estimation: in vitro dissolution and in vivo rat feeding model for a NIST-traceable soil material. Bioaccessibility was measured using a sequential soil extraction in synthetic analogues of human saliva, gastric and intestinal fluids. Bioavailability was measured in Sprague Dawley rats by determining metal levels in the major organs and urine, feces, and blood. Bioaccessibility was found to be a good indicator of relative metal bioavailability. Results are presented from bioaccessible experiments with Cesium in contaminated DOE soils, and total alpha and beta bioaccessibility. The results indicate that the modified methodology for bioaccessibility can be used for specific radionuclide analysis.
Date: September 15, 1999
Creator: Lioy, P. J.; Gallo, M.; Georgopoulos, P.; Tate, R. & Buckley, B.
Object Type: Report
System: The UNT Digital Library
Physics of collisionless scrape-off-layer plasma during normal and off-normal Tokamak operating conditions. (open access)

Physics of collisionless scrape-off-layer plasma during normal and off-normal Tokamak operating conditions.

The structure of a collisionless scrape-off-layer (SOL) plasma in tokamak reactors is being studied to define the electron distribution function and the corresponding sheath potential between the divertor plate and the edge plasma. The collisionless model is shown to be valid during the thermal phase of a plasma disruption, as well as during the newly desired low-recycling normal phase of operation with low-density, high-temperature, edge plasma conditions. An analytical solution is developed by solving the Fokker-Planck equation for electron distribution and balance in the SOL. The solution is in good agreement with numerical studies using Monte-Carlo methods. The analytical solutions provide an insight to the role of different physical and geometrical processes in a collisionless SOL during disruptions and during the enhanced phase of normal operation over a wide range of parameters.
Date: March 15, 1999
Creator: Hassanein, A. & Konkashbaev, I.
Object Type: Report
System: The UNT Digital Library
The PCMDI software and the next generation internet project (open access)

The PCMDI software and the next generation internet project

One problem facing many scientists is not the absence of tools to analyze data, but rather a shortage of interrelated diagnostic software that is consistent, flexible, portable, adaptable, efficient, sharable, and easy to use. Consequently, many scientists are writing their own programs to ingest, manipulate and display data. Debugging and enhancing special purpose software diverts time that otherwise would be spent on research. The result is often not ''friendly'', reusable, or portable, nor does it promote standards within the research community. In response to the needs of the scientific community, PCMDI has developed a suite of software tools for the storage, diagnosis, and visualization of data. PCMDI's principal tools are the Climate Data Analysis Tool (CDAT), the Climate Database Management System (CDMS), and the Visualization and Computation System (VCS). The design goal of this suite of software is to reduce the redundancy encountered so often in scientific analysis and to allow researchers to concentrate on their science. One obstacle to sharing analysis software is the wide variety of data file formats that are in use. Programs must be written to convert data to a user's preferred file format and conventions. This data conversion requires additional expenditure of efforts on testing …
Date: October 15, 1999
Creator: Potter, G L & Williams, D N
Object Type: Article
System: The UNT Digital Library
Waste characterization for radioactive liquid waste evaporators at Argonne National Laboratory - West. (open access)

Waste characterization for radioactive liquid waste evaporators at Argonne National Laboratory - West.

Several facilities at Argonne National Laboratory - West (ANL-W) generate many thousand gallons of radioactive liquid waste per year. These waste streams are sent to the AFL-W Radioactive Liquid Waste Treatment Facility (RLWTF) where they are processed through hot air evaporators. These evaporators remove the liquid portion of the waste and leave a relatively small volume of solids in a shielded container. The ANL-W sampling, characterization and tracking programs ensure that these solids ultimately meet the disposal requirements of a low-level radioactive waste landfill. One set of evaporators will process an average 25,000 gallons of radioactive liquid waste, provide shielding, and reduce it to a volume of six cubic meters (container volume) for disposal. Waste characterization of the shielded evaporators poses some challenges. The process of evaporating the liquid and reducing the volume of waste increases the concentrations of RCIU regulated metals and radionuclides in the final waste form. Also, once the liquid waste has been processed through the evaporators it is not possible to obtain sample material for characterization. The process for tracking and assessing the final radioactive waste concentrations is described in this paper, The structural components of the evaporator are an approved and integral part of the …
Date: February 15, 1999
Creator: Christensen, B. D.
Object Type: Article
System: The UNT Digital Library
Bubble Radiation Detection: Current and Future Capability (open access)

Bubble Radiation Detection: Current and Future Capability

Despite a number of noteworthy achievements in other fields, superheated droplet detectors (SDDs) and bubble chambers (BCs) have not been used for nuclear nonproliferation and arms control. This report examines these two radiation-detection technologies in detail and answers the question of how they can be or should be ''adapted'' for use in national security applications. These technologies involve closely related approaches to radiation detection in which an energetic charged particle deposits sufficient energy to initiate the process of bubble nucleation in a superheated fluid. These detectors offer complete gamma-ray insensitivity when used to detect neutrons. They also provide controllable neutron-energy thresholds and excellent position resolution. SDDs are extraordinarily simple and inexpensive. BCs offer the promise of very high efficiency ({approximately}75%). A notable drawback for both technologies is temperature sensitivity. As a result of this problem, the temperature must be controlled whenever high accuracy is required, or harsh environmental conditions are encountered. The primary findings of this work are listed and briefly summarized below: (1) SDDs are ready to function as electronics-free neutron detectors on demand for arms-control applications. The elimination of electronics at the weapon's location greatly eases the negotiability of radiation-detection technologies in general. (2) As a result of …
Date: November 15, 1999
Creator: Peurrung, AJ & Craig, RA
Object Type: Report
System: The UNT Digital Library
Exploring the Weak Phase Gamma in B+- -> pi K Decays (open access)

Exploring the Weak Phase Gamma in B+- -> pi K Decays

Measurements of the rates for the hadronic decays B{sup {+-}} {r_arrow} {pi}K along with the CP-averaged B{sup {+-}} {r_arrow} {pi}{sup {+-}} {pi}{sup 0} branching ratio can be used to bound and extract the weak phase {gamma} = arg(V{sub ub}*). Using preliminary CLEO data, we obtain the bounds {vert_bar}{gamma}{vert_bar} > 93{degree} at 1 {sigma}, and {vert_bar}{gamma}{vert_bar} > 71{degree} at 90% confidence level.
Date: April 15, 1999
Creator: Neubert, Matthias
Object Type: Report
System: The UNT Digital Library
Recycling of water in bleached kraft pulp mills by using electrodialysis. (open access)

Recycling of water in bleached kraft pulp mills by using electrodialysis.

Conservation of water in bleached kraft pulp mills by recycling the bleach plant effluent directly without treatment will cause accumulation of inorganic ''non-process elements'' (NPEs) and serious operational problems. In this work, an electrodialysis process is being developed for recycling the acidic bleach plant effluent of bleached kraft pulp mills. In this process, electrodialysis functions as a selective kidney to remove inorganic NPEs from bleach plant effluents, before they reach the recovery cycle. Acidic bleach plant effluents from several mills using bleaching sequences based on chlorine dioxide were characterized. The total dissolved solids were mostly inorganic NPEs. Sodium was the predominant cation and chloride was present at significant levels in all these effluents. In laboratory electrodialysis experiments, selective removal of chloride and potentially harmful cations, such as potassium, calcium, and magnesium, were removed efficiently. Rejection of organic compounds was up to 98%. Electrodialysis was shown to be resistant to membrane fouling and scaling, in a 100-hour laboratory experiment. Based on a model mill with 1,000 ton/day pulp production, the economic analysis suggests that the energy cost of electrodialysis is less than $200/day, and the capital cost of the stack is about $500,000.
Date: January 15, 1999
Creator: Fracaro, A. T.; Henry, M. P.; Pfromm, P. & Tsai, S.-P.
Object Type: Article
System: The UNT Digital Library
New experiments elucidating the current limiting mechanisms of Ag-sheathed (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} tapes. (open access)

New experiments elucidating the current limiting mechanisms of Ag-sheathed (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} tapes.

Multiple current limiting mechanisms exist from the nanometer to millimeter scale in Ag-sheathed (Bi,Pb)-2223 tapes. Recent studies of the zero-field critical current density (J{sub c} (0T, 77K)), the irreversibility field (H*) and the crack microstructure elucidate these properties. We show that H*(77K) can vary significantly over the range {approximately}120-260 mT, independently of J{sub c} (0T, 77K). Cracks, actual or incipient, exist on the sub to several hundred micron scale. Surface magneto optical imaging of whole tapes, correlated to subsequent ultrasonic fracture analysis of. the bare 2223 filaments extracted by dissolving away the Ag shows that even composites having J{sub c} (0T, 77K) values of 60 kA/cm{sup 2} exhibit strong signs of unhealed rolling damage. These combined studies show that today's very best 2223 tapes are still far from full optimization.
Date: January 15, 1999
Creator: Anderson, J. W.; Babcock, S. E.; Cai, X. Y.; Dorris, S. E.; Feldmann, M.; Jiang, J. et al.
Object Type: Article
System: The UNT Digital Library
Materials Applications for Non-Lethal: Aqueous Foams (open access)

Materials Applications for Non-Lethal: Aqueous Foams

High expansion aqueous foam is an aggregation of bubbles that has the appearance of soap suds and is used to isolate individuals both visually and acoustically. It was developed in the 1920's in England to fight coal mine fires and has been widely used since for fire fighting and dust suppression. It was developed at Sandia National Laboratories (SNL) in the 1970's for nuclear safeguards and security applications. In the mid-1990s, the National Institute of Justice (NIJ), the research arm of the Department of Justice, began a project with SNL to determine the applicability of high expansion aqueous foam for correctional applications. NIJ funded the project as part of its search for new and better less-than-lethal weapons for responding to violent and dangerous individuals, where other means of force could lead to serious injuries. The phase one objectives of the project were to select a low-to-no toxicity foam concentrate (foaming agent) with physical characteristics suited for use in a single cell or large prison disturbances, and to determine if the selected foam concentrate could serve as a carrier for Oleoresin Capsicum (OC) irritant. The phase two objectives were to conduct an extensive toxicology review of the selected foam concentrate and …
Date: September 15, 1999
Creator: GOOLSBY,TOMMY D. & SCOTT,STEVEN H.
Object Type: Article
System: The UNT Digital Library
Atmospheric Radiation Measurement Program Facilities Newsletter, June 1999. (open access)

Atmospheric Radiation Measurement Program Facilities Newsletter, June 1999.

Monthly newsletter discussing news and activities related to the Atmospheric Radiation Measurement Program, articles about weather and atmospheric phenomena, and other related topics.
Date: July 15, 1999
Creator: Atmospheric Radiation Measurement Program (U.S.)
Object Type: Journal/Magazine/Newsletter
System: The UNT Digital Library