Progress and future plans for MPC and A at Chelyabinsk-70 (open access)

Progress and future plans for MPC and A at Chelyabinsk-70

This paper describes that portion of the Nuclear Materials Protection, Control, and Accounting (MPC and A) program that is directed specifically to the needs of the All Russian Scientific Research Institute of Technical Physics (VNIITF), also called Chelyabinsk-70. Chelyabinsk-70 is located in the Ural Mountains, approximately 2000 km east of Moscow and 100 km south of Ekaterinburg. The MPC and A work that has been completed, is underway and planned at the facility will be described. During the first two years of the VNIITF project, emphasis was on the Pulse Research Reactor Facility (PRR), which contains one metal and two liquid pulse reactors and associated nuclear material storage rooms and a control center. A commissioning of the PRR was held in May of 1998. With the completion of the MPC and A work in the PRR, new physical protection work is focusing on other areas. VNIITF-wide physical protection initiatives underway include access control and computerized badging systems, and a central MPC and A control system. Measured physical inventory taking is a high priority for the VNIITF Project Team. A VNIITF-wide computerized accounting system is also being developed for the large and diverse inventory of nuclear material subject to MPC and …
Date: July 8, 1999
Creator: Apt, K.; Blasy, J.; Bukin, D.; Cahalane, P.; Churikov, Y.; Curtis, D. et al.
System: The UNT Digital Library
Characterizing the altered zone at Yucca Mountain: The beginning of a testing strategy (open access)

Characterizing the altered zone at Yucca Mountain: The beginning of a testing strategy

The concept of a disturbed zone surrounding the mined openings of a potential geologic repository for high-level radioactive waste was introduced by the US Nuclear Regulatory Commission (NRC) as a region to be excluded for determining groundwater travel time to the accessible environment, but to be included for determining the impact of underground construction and radioactive decay heat on groundwater movement and radionuclide transport for total system performance analysis. This paper explores both the regulatory and technical necessity for characterizing and modeling a larger region -- the altered zone -- within which the temperature is increased significantly by heat from the high-level waste. Particular attention is given to addressing the effects of heterogeneity on groundwater flux and travel time, showing how these effects might be modeled simply on a macroscopic scale, and outlining its parameters. The effect of uncertainty in the parameter values on the performance of a potential repository can then be easily handled by probabilistic analysis.
Date: January 8, 1992
Creator: Chesnut, D.A.
System: The UNT Digital Library
Beam tests of the 12 MHz RFQ RIB injector for ATLAS. (open access)

Beam tests of the 12 MHz RFQ RIB injector for ATLAS.

In recent tests without beam, the Argonne 12 MHz split-coaxial radio-frequency quadruple (RFQ) achieved a cw intervane voltage of more than 100 kV, the design operating voltage for the device. This voltage is sufficient for the RFQ to function as the first stage of a RIB injector for the Argonne Tandem Linear Accelerator System (ATLAS). Previously reported beam dynamics calculations for the structure predict longitudinal emittance growth of only a few keV{center_dot}ns for beams of mass 132 and above with transverse emittance of 0.27 {pi} mm{center_dot}mrad (normalized). Such beam quality is not typical of RFQ devices. The work reported here is preparation for tests with beams of mass up to 132. Beam diagnostic stations are being developed to measure the energy gain and beam quality of heavy ions accelerated by the RFQ using the Dynamitron accelerator facility at the ANL Physics Division as the injector. Beam diagnostic development includes provisions for performing the measurements with both a Si charged-particle detector and an electrostatic energy spectrometer system.
Date: February 8, 1999
Creator: Kaye, R. A.
System: The UNT Digital Library
Medical applications of ultra-short pulse lasers (open access)

Medical applications of ultra-short pulse lasers

The medical applications for ultra short pulse lasers (USPLs) and their associated commercial potential are reviewed. Short pulse lasers offer the surgeon the possibility of precision cutting or disruption of tissue with virtually no thermal or mechanical damage to the surrounding areas. Therefore the USPL offers potential improvement to numerous existing medical procedures. Secondly, when USPLs are combined with advanced tissue diagnostics, there are possibilities for tissue-selective precision ablation that may allow for new surgeries that cannot at present be performed. Here we briefly review the advantages of short pulse lasers, examine the potential markets both from an investment community perspective, and from the view. of the technology provider. Finally nominal performance and cost requirements for the lasers, delivery systems and diagnostics and the present state of development will be addressed.
Date: June 8, 1999
Creator: Kim, B. M. & Marion, J. E.
System: The UNT Digital Library
The BTeV Trigger System (open access)

The BTeV Trigger System

BTeV is a dedicated beauty and charm experiment proposed for the Fer- milab Tevatron. The broad physics program envisaged for BTeV requires a trigger that is efficient for a wide variety of heavy-quark decays, includ- ing those to all-hadronic final states. To achieve this, we plan to trigger on evidence of detached vertices at the very first trigger level, taking ad- vantage of fast-readout pixel detectors to facilitate fast pattern recognition. Simulations show that 100-to-1 rejection of light-quark background events can be achieved at Level 1 using specialized trackfinding hardware, and that an additional factor of 10 to 100 in data reduction can be achieved using general-purpose-processor farms at Levels 2 and 3. This is adequate to allow data-taking at luminosities in excess of 2 x 10<sup>32</sup> cm<sup>-2</sup>s<sup>-1</sup>.
Date: October 8, 1999
Creator: Kaplan, Daniel M.
System: The UNT Digital Library
The Role of Strong Coupling in Z-Pinch-Driven Approaches to High Yield Inertial Confinement Fusion (open access)

The Role of Strong Coupling in Z-Pinch-Driven Approaches to High Yield Inertial Confinement Fusion

Peak x-ray powers as high as 280 {+-} 40 TW have been generated from the implosion of tungsten wire arrays on the Z Accelerator at Sandia National Laboratories. The high x-ray powers radiated by these z-pinches provide an attractive new driver option for high yield inertial confinement fusion (ICF). The high x-ray powers appear to be a result of using a large number of wires in the array which decreases the perturbation seed to the magnetic Rayleigh-Taylor (MRT) instability and diminishes other 3-D effects. Simulations to confirm this hypothesis require a 3-D MHD code capability, and associated databases, to follow the evolution of the wires from cold solid through melt, vaporization, ionization, and finally to dense imploded plasma. Strong coupling plays a role in this process, the importance of which depends on the wire material and the current time history of the pulsed power driver. Strong coupling regimes are involved in the plasmas in the convolute and transmission line of the powerflow system. Strong coupling can also play a role in the physics of the z-pinch-driven high yield ICF target. Finally, strong coupling can occur in certain z-pinch-driven application experiments.
Date: November 8, 1999
Creator: MEHLHORN,THOMAS A.; DESJARLAIS,MICHAEL P.; HAILL,THOMAS A.; LASH,JOEL S.; ROSENTHAL,STEPHEN E.; SLUTZ,STEPHEN A. et al.
System: The UNT Digital Library
Impedance considerations for the Intense Pulse Neutron Source (IPNS) Rapid Cycling Synchrotron (RCS). (open access)

Impedance considerations for the Intense Pulse Neutron Source (IPNS) Rapid Cycling Synchrotron (RCS).

The use of Second Harmonic (SH) rf is being investigated to increase the Rapid Cycling Synchrotron (RCS) current limit. Hofmann-Pedersen distributions are employed to provide analytical guidance. The SH phase {theta}, is optimized using a numerical analysis to maximize transmission and minimize instabilities. The effect of the RCS stainless steel liner on the impedance of the machine is also discussed.
Date: September 8, 1999
Creator: Brumwell, F. R.; Dooling, J. C. & McMichael, G. E.
System: The UNT Digital Library
Online monitoring in the upcoming Fermilab Tevatron Run II (open access)

Online monitoring in the upcoming Fermilab Tevatron Run II

We describe the online event monitoring systems using ROOT [1] for the CDF and D0 collaborations in the upcoming Fermilab Tevatron runII. The CDF and D0 experiments consist of many detector subsystems and will run in a high rate large bandwidth data transfer environment. In the experiments, it is crucial to monitor the performance of each subsystem and the integrity of the data, in real time with minimal interruption. ROOT is used as the main analysis tool for the monitoring systems and its GUI is used to browse the results via socket, allowing multiple GUI client connections.
Date: September 8, 1999
Creator: Canal, P.; Kowalkowski, J.; Maeshima, K.; Yu, J.; Wenzel, H.; Snow, J. et al.
System: The UNT Digital Library
In-vessel fluid flow measurements using thermocouples cross-correlation. (open access)

In-vessel fluid flow measurements using thermocouples cross-correlation.

Fluid flow rate in high temperature and pressure vessels can be difficult to measure due to the associated harsh environment, inaccessible locations and pressure boundary integrity concerns. However, by using quick response miniature thermocouples to measure the naturally occurring temperature variations within the flow, the fluid velocity can be inferred from the transit time analysis. This flow measurement technique has other advantages such as the flow profile is not significantly disturbed, no additional flow restrictions introduced and the system fiction factor is not increased. Furthermore, since the measured flow rate is generally unaffected by the global system dynamics, such as heat increases or losses, as well as changes in the flow regimes, the location of the thermocouple pairs is extremely flexible. Due to the mentioned advantages, the thermocouple cross-correlation flow measurement method has been developed for use at the Purdue University Multi-Dimensional Integral Test Assembly (PUMA). Currently, thermocouple cross-correlation technique is used to measure the Reactor Pressure Vessel downcomer fluid velocity and the suppression pool in-vessel natural circulation velocity.
Date: May 8, 1998
Creator: NguyenLe, Q.
System: The UNT Digital Library
Progress toward hydrogen peroxide micropulsion (open access)

Progress toward hydrogen peroxide micropulsion

A new self-pressurizing propulsion system has liquid thrusters and gas jet attitude control without heavy gas storage vessels. A pump boosts the pressure of a small fraction of the hydrogen peroxide, so that reacted propellant can controllably pressurize its own source tank. The warm decomposition gas also powers the pump and is supplied to the attitude control jets. The system has been incorporated into a prototype microsatellite for terrestrial maneuvering tests. Additional progress includes preliminary testing of a bipropellant thruster, and storage of unstabilized hydrogen peroxide in small sealed tanks.
Date: July 8, 1999
Creator: Whitehead, J. C.; Dittman, M. D. & Ledebuhr, A. G.
System: The UNT Digital Library
Low-temperature MOCVD growth of oriented PbZr{sub x}Ti{sub 1-x}O{sub 3} thin films on Si substrates. (open access)

Low-temperature MOCVD growth of oriented PbZr{sub x}Ti{sub 1-x}O{sub 3} thin films on Si substrates.

Polycrystalline Pb(Zr{sub 0.6}Ti{sub 0.4})O{sub 3} (PZT) thin films, 3000-6000 {angstrom} thick, have been grown by metal-organic chemical vapor deposition (MOCVD) on (111)Pt/Ti/SiO{sub 2}/Si substrates at temperatures as low as 450-525 C. Random and (111)-oriented, or occasionally (100)-oriented, PZT films can be deposited directly on (111)Pt/Ti/SiO{sub 2}/Si. In addition, highly (100)-oriented films can be deposited consistently by using 150-250 {angstrom} thick (100)-oriented PbTiO{sub 3} (PT) or TiO{sub 2} as a template. Films were characterized by X-ray diffraction, electron microscopy, and electrical measurements. The as-grown (100)-oriented films on (111)Pt/TiSiO{sub 2}/Si substrates exhibited dielectric constants ({var_epsilon}{sub r}) of up to 600, remnant polarization (P{sub r}) of 40 {micro}C/cm{sup 2}, coercive field of 55 kV/cm, and breakdown field of 2-6 x 10{sub 7} V/m.
Date: May 8, 1998
Creator: Chen, N.
System: The UNT Digital Library
Preserving Alaska's early Cold War legacy. (open access)

Preserving Alaska's early Cold War legacy.

The US Air Force owns and operates numerous facilities that were constructed during the Cold War era. The end of the Cold War prompted many changes in the operation of these properties: missions changed, facilities were modified, and entire bases were closed or realigned. The widespread downsizing of the US military stimulated concern over the potential loss of properties that had acquired historical value in the context of the Cold War. In response, the US Department of Defense in 1991 initiated a broad effort to inventory properties of this era. US Air Force installations in Alaska were in the forefront of these evaluations because of the role of the Cold War in the state's development and history and the high interest on the part of the Alaska State Historic Preservation Officer (SHPO) in these properties. The 611th Air Support Group (611 ASG) owns many of Alaska's early Cold War properties, most were associated with strategic air defense. The 611 ASG determined that three systems it operates, which were all part of the integrated defense against Soviet nuclear strategic bomber threat, were eligible for the National Register of Historic Places (NRHP) and would require treatment as historic properties. These systems include …
Date: March 8, 1999
Creator: Hoffecker, J. & Whorton, M.
System: The UNT Digital Library
THE 15 LAYER SILICON DRIFT DETECTOR TRACKER IN EXPERIMENT 896. (open access)

THE 15 LAYER SILICON DRIFT DETECTOR TRACKER IN EXPERIMENT 896.

Large linear silicon drift detectors have been developed and are in production for use in several experiments. Recently 15 detectors were used as a tracking device in BNL-AGS heavy ion experiment (E896). The detectors were successfully operated in a 6.2 T magnetic field. The behavior of the detectors, such as drift uniformity, resolution, and charge collection efficiency are presented. The effect of the environment on the detector performance is discussed. Some results from the experimental run are presented. The detectors performed well in an experimental environment. This is the first tracking application of these detectors.
Date: November 8, 1998
Creator: Pandy, S. U.
System: The UNT Digital Library
Manufacturing diamond films using copper vapour lasers (open access)

Manufacturing diamond films using copper vapour lasers

Fifty nanosecond pulses of visible light have been used to produce hard, hydrogen-free diamond-like-carbon (DLC) films at irradiances between 5 x 10{sup 8} and 5 x 10{sup 10} W/cm{sup 2} The films were characterized by a number of techniques including: Raman spectroscopy, Electron Energy Loss Spectroscopy (EELS), atomic force microscopy, and spectroscopic ellipsometry. The cost for manufacturing DLC with high average power, high-pulse repetition frequency, visible light is low enough to compete with other diamond thin film production methods.
Date: January 8, 1996
Creator: McLean, M., LLNL
System: The UNT Digital Library
Subcarrier multiplexing system with built-in dispersion reduction (open access)

Subcarrier multiplexing system with built-in dispersion reduction

Dispersion is effectively reduced in a 1550-nm subcarrier-multiplexed fiber link by using optical pre-filtering at the receiver. Recent experimental results demonstrate transmission of two 2.5 Gbit/s data channels over 220 km of ordinary single-mode fiber.
Date: September 8, 1995
Creator: Sargis, P. D.; Haigh, R. E. & McCammon, K. G.
System: The UNT Digital Library
Uranium and Plutonium Solution Assays by Transmission-Corrected X-Ray Fluorescence (open access)

Uranium and Plutonium Solution Assays by Transmission-Corrected X-Ray Fluorescence

We have refined and tested a previously developed x-ray fluorescence analysis technique for uranium and plutonium solutions that compensates for variations in the absorption of the exciting gamma rays and fluorescent x-rays. We use {sup 57}Co to efficiently excite the K lines of the elements, and a mixed {sup 57}Co plus {sup 153}Gd transmission source to correct for variations in absorption. The absorption correction is a unique feature of our technique. It is possible to accurately calibrate the system with a single solution standard. There does not need to be a close match in composition (i.e., absorption) between the standard(s) and solutions to be analyzed. Specially designed equipment incorporates a planar intrinsic germanium detector, excitation and transmission radioisotopes, and specimen holder. The apparatus can be inserted into a rubber glove of a glovebox, keeping the apparatus outside and the solutions inside the glovebox, thereby protecting the user and the equipment from possible contamination. An alternate design may be used in chemical reprocessing plants, providing continuous monitoring, by measuring the trans-actinides through stainless steel piping. This technique has been tested at the Bochvar Research Institute of Inorganic Materials in Moscow for possible use in the Russian complex of nuclear facilities. This …
Date: September 8, 1999
Creator: Ryon, R. W.; Ruhter, W. D.; Rudenko, V.; Sirontinin, A. & Petrov, A. A.
System: The UNT Digital Library
Signal analysis approach to ultrasonic evaluation of diffusion bond quality (open access)

Signal analysis approach to ultrasonic evaluation of diffusion bond quality

Solid state bonds like the diffusion bond are attractive techniques for joining dissimilar materials since they are not prone to the defects that occur with fusion welding. Ultrasonic methods can detect the presence of totally unbonded regions but have difficulty sensing poor bonded areas where the substrates are in intimate contact. Standard ultrasonic imaging is based on amplitude changes in the signal reflected from the bond interface. Unfortunately amplitude alone is not sensitive to bond quality. We demonstrated that there is additional information in the ultrasonic signal that correlates with bond quality. In our approach we interrogated a set of dissimilar diffusion bonded samples with broad band ultrasonic signals. The signals were digitally processed and the characteristics of the signals that corresponded to bond quality were determined. These characteristics or features were processed with pattern recognition algorithms to produce predictions of bond quality. The predicted bond quality was then compared with the destructive measurement to assess the classification capability of the ultrasonic technique
Date: June 8, 1999
Creator: Chinn, D & Thomas, G
System: The UNT Digital Library
Photovoltaic module performance and durability following long-term field exposure (open access)

Photovoltaic module performance and durability following long-term field exposure

Our investigations of both new and field-aged photovoltaic modules have indicated that, in general, today's commercially available modules area highly reliable product. However, by using new test procedures, subtle failure mechanisms have also been identified that must be addressed in order to achieve 30-year module lifetimes. This paper summarizes diagnostic test procedures, results, and implications of in-depth investigations of the performance and durability characteristics of commercial modules after long-term field exposure. A collaborative effort with U.S. module manufacturers aimed at achieving 30-year module lifetimes is also described.
Date: September 8, 1998
Creator: Ellibee, D. E.; Hansen, B. R.; King, D. L.; Kratochvil, J. A. & Quintana, M. A.
System: The UNT Digital Library
Evaluation of Fiber Separators for Use in Thermal Batteries (open access)

Evaluation of Fiber Separators for Use in Thermal Batteries

Fiberglass tape and borosilicate filter discs impregnated with molten LiCl-KCl eutectic were examined for potential use as separators for high-temperature LiSi/LiCl-KCl/FeS{sub 2} thermal batteries. Test discs were punched from these materials and evaluated at 400 C in single cells at a steady-state current of 63 mA/cm{sup 2}. The performance generally improved with electrolyte loading for most of the materials. Better results were obtained with the filter discs than with the tape. The best overall results were obtained with Whatman GF/A discs. Active lives for cells with these separators were about 85% of the standard cells with pressed-powder separators. More work with other materials and electrolytes over a wider temperature range is underway, along with 5-cell-battery tests.
Date: September 8, 1999
Creator: GUIDOTTI,RONALD A. & REINHARDT,FREDERICK W.
System: The UNT Digital Library
Optimization of a readout architecture for pixel detectors (open access)

Optimization of a readout architecture for pixel detectors

This paper analyzes in detail some theoretical aspects in the modeling of a readout architecture for pixel detectors. In fact, these problems are common to the design of data acquisition systems and other processes containing buffers and where the input and output signals can be expressed by probability density functions. It is the purpose of this paper to point out that the same type of analysis can be extended to other systems with the benefit of saving time in long Montecarlo simulations and prototype design. The example case in which this paper is based on is the readout architecture of a column-based pixel detector amplifier and discriminator chip containing more than 3000 pixels of 50&micro; x 400&micro;. Several readout strategies are compared searching for an optimal design, which minimizes data loss and maximizes throughput. In particular, the probability of loosing pixel hits by overflowing the readout system is minimized studying the behavior of the stochastic Marcov process. Also, the communication channel bandwidths and local buffering are optimized.
Date: October 8, 1999
Creator: Cancelo, Gustavo I. E.
System: The UNT Digital Library
BWR drywell behavior under steam blowdown. (open access)

BWR drywell behavior under steam blowdown.

Historically, thermal hydraulics analyses on Large Break Loss of Coolant Accidents (LOCA) have been focused on the transients within the reactor or steam generator. Few have studied the effects of steam blowdown on the containment building. This paper discusses some theoretical issues as well as presenting numerical and experimental results of the blowdown tests performed at the Purdue University Multi-Dimensional Integrated Test Assembly (PUMA).
Date: May 8, 1998
Creator: NguyenLe, Q.
System: The UNT Digital Library
Numerical relativity in a distributed environment. (open access)

Numerical relativity in a distributed environment.

We have found that the hardware and software infrastructure exists to simulate general relativity problems in a distributed computational environment, at some cost in performance. We examine two different issues for running the Cactus code in such a distributed environment The first issue is running a Cactus simulation on multiple parallel computer systems. Our objective is to perform larger simulations than are currently possible on a single parallel computer. We distribute Cactus simulations across multiple supercomputers using the mechanisms provided by the Globus toolkit. In particular, we use Globus mechanisms for authentication, access to remote computer systems, file transfer, and communication. The Cactus code uses MPI for communication and makes use of an MPI implementation layered atop Globus communication mechanisms. These communication mechanisms allow a MPI application to be executed on distributed resources. We find that without performing any code optimizations, our simulations ran 48% to 100% slower when using an Origin at the National Center for Supercomputing Applications (NCSA) and an Onyx2 at Argonne National Laboratory (ANL). We also ran simulations between Cray T3Es in Germany and a T3E at the San Diego Supercomputing Center (SDSC). Running between the T3Es in Germany resulted in an increase in execution time …
Date: February 8, 1999
Creator: Benger, W.; Foster, I.; Novotny, J.; Seidel, E.; Shalf, J.; Smith, W. et al.
System: The UNT Digital Library
Laser diagnostic for high-energy, laser fusion drivers (open access)

Laser diagnostic for high-energy, laser fusion drivers

A complete set of diagnostics for use on a frequency-tripled high-energy glass laser system is described. We employed high resolution imaging, temporal pulse-shape, beam bandwidth, phase-front, and precision energy instrumentation.
Date: November 8, 1994
Creator: Burkhart, S.C.; Behrendt, W. & Smith, I.
System: The UNT Digital Library
Nitrogen Implantation Effects on the Chemical Bonding and Hardness of Boron and Boron Nitride Coatings (open access)

Nitrogen Implantation Effects on the Chemical Bonding and Hardness of Boron and Boron Nitride Coatings

Boron nitride (BN) coatings are deposited by the reactive sputtering of fully dense, boron (B) targets utilizing an argon-nitrogen (Ar-N{sub 2}) reactive gas mixture. Near-edge x-ray absorption fine structure analysis reveals features of chemical bonding in the B 1s photoabsorption spectrum. Hardness is measured at the film surface using nanoindentation. The BN coatings prepared at low, sputter gas pressure with substrate heating are found to have bonding characteristic of a defected hexagonal phase. The coatings are subjected to post-deposition nitrogen (N{sup +} and N{sub 2}{sup +}) implantation at different energies and current densities. The changes in film hardness attributed to the implantation can be correlated to changes observed in the B 1s NEXAFS spectra.
Date: February 8, 1999
Creator: Anders, S.; Felter, T.; Hayes, J.; Jankowski, Alan Frederic; Patterson, R.; Poker, D. et al.
System: The UNT Digital Library