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Field Errors in Hybrid Insertion Devices (open access)

Field Errors in Hybrid Insertion Devices

Hybrid magnet theory as applied to the error analyses usedin the design of Advanced Light Source (ALS) insertion devices isreviewed. Sources of field errors in hybrid insertion devices arediscussed.
Date: February 3, 1995
Creator: Schlueter, R.D.
System: The UNT Digital Library
Diagnostics for the detection and evaluation of laser induced damage (open access)

Diagnostics for the detection and evaluation of laser induced damage

The Laser Damage and Conditioning Group at LLNL is evaluating diagnostics which will help make damage testing more efficient and reduce the risk of damage during laser conditioning. The work to date has focused on photoacoustic and scattered light measurements on 1064-nm wavelength HfO{sub 2}/SiO{sub 2} multilayer mirror and polarizer coatings. Both the acoustic and scatter diagnostics have resolved 10 {mu}m diameter damage points in these coatings. Using a scanning stage, the scatter diagnostic can map both intrinsic and laser-induced scatter. Damage threshold measurements obtained using scatter diagnostics compare within experimental error with those measured using 100x Nomarski microscopy. Scatter signals measured during laser conditioning can be used to detect damage related to nodular defects.
Date: January 3, 1995
Creator: Sheehan, L.; Kozlowski, M. & Rainer, F.
System: The UNT Digital Library
Weak matrix elements on the lattice - Circa 1995 (open access)

Weak matrix elements on the lattice - Circa 1995

Status of weak matrix elements is reviewed. In particular, e{prime}/e, B {yields} K*{gamma}, B{sub B} and B{sub B}, are discussed and the overall situation with respect to the lattice effort and some of its phenomenological implications are summarised. For e{prime}/e the need for the relevant matrix elements is stressed in view of the forthcoming improved experiments. For some of the operators, (e.g. O{sub 6}), even bound on their matrix elements would be very helpful. On B {yields} K{degrees}{gamma}, a constant behavior of T{sub 2} appears disfavored although dependence of T{sub 2} could, of course, be milder than a simple pole. Improved data is badly needed to settle this important issue firmly, especially in view of its ramification for extractions of V{sub td} from B {yields} {rho}{gamma}. On B{sub {kappa}}, the preliminary result from JLQCD appears to contradict Sharpe et al. JLQCD data seems to fit very well to linear {alpha} dependence and leads to an appreciably lower value of B{sub {kappa}}. Four studies of B{sub {kappa}} in the {open_quotes}full{close_quotes} (n{sub f} = 2) theory indicate very little quenching effects on B{sub {kappa}}; the full theory value seems to be just a little less than the quenched result. Based on expectations …
Date: October 3, 1995
Creator: Soni, A.
System: The UNT Digital Library
Detecting leaks in hydrocarbon storage tanks using electrical resistance tomography (open access)

Detecting leaks in hydrocarbon storage tanks using electrical resistance tomography

Large volumes of hydrocarbons are stored worldwide in surface and underground tanks. It is well documented [1] that all too often these tanks are found to leak, resulting in not only a loss of stored inventory but, more importantly, contamination to soil and groundwater. Two field experiments are reported herein to evaluate the utility of electrical resistance tomography (ERT) for detecting and locating leaks as well as delineating any resulting plumes emanating from steel underground storage tanks (UST). Current leak detection methods for single shell tanks require careful inventory monitoring, usually from liquid level sensors within the tank, or placement of chemical sensors in the soil under and around the tank. Liquid level sensors can signal a leak but are limited in sensitivity and, of course, give no information about the location or the leak or the distribution of the resulting plume. External sensors are expensive to retrofit and must be very densely spaced to assure reliable detection, especially in heterogeneous soils. The rational for using subsurface tomography is that it may have none of these shortcomings.
Date: April 3, 1995
Creator: Daily, W.; Ramirez, A.; LaBrecque, D. & Binley, A.
System: The UNT Digital Library
Mapping hidden aircraft defects with dual-band infrared computed tomography (open access)

Mapping hidden aircraft defects with dual-band infrared computed tomography

Infrared computed tomography (IRCT) is a promising, non-contact, nondestructive evaluation tool used to inspect the mechanical integrity of large structures. We describe on-site, proof-of-principle demonstrations of IRCt to inspect defective metallic and composite structures. The IRCT system captures time sequences of heat-stimulated, dual-band infrared (DBIR) thermal maps for flash-heated and naturally-heated targets. Our VIEW algorithms produce co-registered thermal, thermal inertia, and thermal-timegram maps from which we quantify the percent metal-loss corrosion damage for airframes and the defect sites, depths, and host-material physical properties for composite structures. The IRCT method clarifies the type of defect, e.g., corrosion, fabrication, foreign-material insert, delamination, unbond, void, and quantifies the amount of damage from the defect, e.g., the percent metal-loss from corrosion in metal structures, the depth, thickness, and areal extent of heat damage in multi-layered composite materials. Potential long-term benefits of IRCT technology are in-service monitoring of incipient corrosion damage, to avoid catastrophic failure and production-monitoring of cure states for composite materials.
Date: April 3, 1995
Creator: Del Grande, N. K. & Durbin, P. F.
System: The UNT Digital Library
The evolution of ultra-intense, short-pulse lasers in underdense plasmas (open access)

The evolution of ultra-intense, short-pulse lasers in underdense plasmas

The propagation of short-pulse lasers through underdense plasmas at ultra-high intensities (I {>=}10{sup 19}W/cm) is examined. The pulse evolution is found to be significantly different than it is for moderate intensities. Rather than beam breakup from self-modulation, Raman forward scattering and laser hose instabilities the behavior is dominated by leading edge erosion. A differential equation which describes local pump depletion is derived and used to analyze the formation and evolution of the erosion. This pulse erosion is demonstrated with one dimensional particle in cell (PIC) simulations. In addition, two dimensional simulations are presented which show pulse erosion along with other effects such as channeling and diffraction.
Date: November 3, 1995
Creator: Decker, C. D.; Mori, W. B. & Tzeng, K. C.
System: The UNT Digital Library
Compton backscattering of intracavity storage ring free-electron laser radiation (open access)

Compton backscattering of intracavity storage ring free-electron laser radiation

We discuss the {gamma}{minus} ray production by Compton backscattering of intracavity S.R. FEL radiation. We use a semi-analytical model which provides the build up of the signal combined with the storage ring damping mechanism and derive simple relations yielding the connection between backscattered photons brightness and the intercavity laser equilibrium intensity.
Date: November 3, 1995
Creator: Dattoli, G.; Giannessi, L.; Torre, A. & Altobelli, G.
System: The UNT Digital Library
Pyrochemical processes for the recovery of weapons grade plutonium either as a metal or as PuO{sub 2} for use in mixed oxide reactor fuel pellets (open access)

Pyrochemical processes for the recovery of weapons grade plutonium either as a metal or as PuO{sub 2} for use in mixed oxide reactor fuel pellets

The authors have developed two processes for the recovery of weapons grade Pu, as either Pu metal or PuO{sub 2}, that are strictly pyrochemical and do not produce any liquid waste. Large amounts of Pu metal (up to 4 kg.), in various geometric shapes, have been recovered by a hydride/dehydride/casting process (HYDEC) to produce metal ingots of any desired shape. The three processing steps are carried out in a single compact apparatus. The experimental technique and results obtained will be described. The authors have prepared PuO{sub 2} powders from weapons grade Pu by a process that hydrides the Pu metal followed by the oxidation of the hydride (HYDOX process). Experimental details of the best way to carry out this process will be presented, as well as the characterization of both hydride and oxide powders produced.
Date: November 3, 1995
Creator: Colmenares, C. A.; Ebbinghaus, B. B. & Bronson, M. C.
System: The UNT Digital Library
Off-training-set error for the Gibbs and the Bayes optimal generalizers (open access)

Off-training-set error for the Gibbs and the Bayes optimal generalizers

In this paper we analyze the average off-training-set behavior of the Bayes-optimal and Gibbs learning algorithms. We do this by exploiting the concept of refinement, which concerns the relationship between probability distributions. For non-uniform sampling distributions the expected off training-set error for both learning algorithms can rise with, training set size. However we show in this paper that for uniform sampling and either algorithm, the expected error is a non-increasing function of training set size. For uniform sampling distributions, we also characterize the priors for which the expected error of the Bayes-optimal algorithm stays constant. In addition we show that when the target function is fixed, expected off-training-set error can increase with training set size if and only if the expected error averaged over all targets decreases with training set size. Our results hold for arbitrary noise and arbitrary loss functions.
Date: January 3, 1995
Creator: Grossman, T.; Knill, E. & Wolpert, D.
System: The UNT Digital Library
A zinc-air battery and flywheel zero emission vehicle (open access)

A zinc-air battery and flywheel zero emission vehicle

In response to the 1990 Clean Air Act, the California Air Resources Board (CARB) developed a compliance plan known as the Low Emission Vehicle Program. An integral part of that program was a sales mandate to the top seven automobile manufacturers requiring the percentage of Zero Emission Vehicles (ZEVs) sold in California to be 2% in 1998, 5% in 2001 and 10% by 2003. Currently available ZEV technology will probably not meet customer demand for range and moderate cost. A potential option to meet the CARB mandate is to use two Lawrence Livermore National Laboratory (LLNL) technologies, namely, zinc-air refuelable batteries (ZARBs) and electromechanical batteries (EMBs, i. e., flywheels) to develop a ZEV with a 384 kilometer (240 mile) urban range. This vehicle uses a 40 kW, 70 kWh ZARB for energy storage combined with a 102 kW, 0.5 kWh EMB for power peaking. These technologies are sufficiently near-term and cost-effective to plausibly be in production by the 1999-2001 time frame for stationary and initial vehicular applications. Unlike many other ZEVs currently being developed by industry, our proposed ZEV has range, acceleration, and size consistent with larger conventional passenger vehicles available today. Our life-cycle cost projections for this technology are …
Date: October 3, 1995
Creator: Tokarz, F.; Smith, J. R.; Cooper, J.; Bender, D. & Aceves, S.
System: The UNT Digital Library
Recirculating induction accelerators for inertial fusion: Prospects and status (open access)

Recirculating induction accelerators for inertial fusion: Prospects and status

The US is developing the physics and technology of induction accelerators for heavy-ion beam-driven inertial fusion. The recirculating induction accelerator repeatedly passes beams through the same set of accelerating and focusing elements, thereby reducing both the length and gradient of the accelerator structure. This promises an attractive driver cost, if the technical challenges associated with recirculation can be met. Point designs for recirculator drivers were developed in a multi-year study by LLNL, LBNL, and FM Technologies, and that work is briefly reviewed here. To validate major elements of the recirculator concept, we are developing a small (4-5-m diameter) prototype recirculator which will accelerate a space-charge-dominated beam of K{sup +} ions through 15 laps, from 80 to 320 keV and from 2 to 8 mA. Transverse beam confinement is effected via permanent-magnet quadrupoles; bending is via electric dipoles. This ``Small Recirculator`` is being developed in a build-and-test sequence of experiments. An injector, matching section, and linear magnetic channel using seven half-lattice periods of permanent-magnet quadrupole lenses are operational. A prototype recirculator half-lattice period is being fabricated. This paper outlines the research program, and presents initial experimental results.
Date: September 3, 1995
Creator: Friedman, A.; Barnard, J. J. & Cable, M. D.
System: The UNT Digital Library
An impulse radar array for detecting land mines (open access)

An impulse radar array for detecting land mines

The Lawrence Livermore National Laboratory has developed radar and imaging technologies with potential application in demining efforts. A patented wideband (impulse) radar that is very compact, very low cost, and very low power, has been demonstrated in test fields to be able to detect and image nonmetallic land mines buried in 2-10 cm of soil. The scheme takes advantage of the very short radar impulses and the ability to form a large synthetic aperture with many small individual units, to generate high resolution 2-D or 3-D tomographic images of the mine and surrounding ground. Radar range calculations predict that a vehicle-mounted or man-carried system is quite feasible using this technology. This paper presents the results of field tests using a prototype unit and describes practical mine detection system concepts. Predicted capabilities in terms of stand-off range and radiated power requirements are discussed.
Date: April 3, 1995
Creator: Gavel, D. T.; Mast, J. E.; Warhus, J. & Azevedo, S. G.
System: The UNT Digital Library
Iron free permanent magnet systems for charged particle beam optics (open access)

Iron free permanent magnet systems for charged particle beam optics

The strength and astounding simplicity of certain permanent magnet materials allow a wide variety of simple, compact configurations of high field strength and quality multipole magnets. Here we analyze the important class of iron-free permanent magnet systems for charged particle beam optics. The theory of conventional segmented multipole magnets formed from uniformly magnetized block magnets placed in regular arrays about a circular magnet aperture is reviewed. Practical multipole configurations resulting are presented that are capable of high and intermediate aperture field strengths. A new class of elliptical aperture magnets is presented within a model with continuously varying magnetization angle. Segmented versions of these magnets promise practical high field dipole and quadrupole magnets with an increased range of applicability.
Date: September 3, 1995
Creator: Lund, S. M. & Halbach, K.
System: The UNT Digital Library
Effect of cavity design on optical parametric oscillator performance (open access)

Effect of cavity design on optical parametric oscillator performance

The effect of resonator cavity design on parametric oscillator performance is investigated theoretically. Certain unstable resonators produce superior energy conversion and beam quality than traditional resonators.
Date: October 3, 1995
Creator: Neuman, W. A. & Velsko, S. P.
System: The UNT Digital Library
Gamma-ray imaging as a tool for uranium processing plants (open access)

Gamma-ray imaging as a tool for uranium processing plants

Gamma-radiation is frequently used as an analysis and characterization signal to monitor material in the nuclear fuel processing cycle. The selection as a diagnostic is self-evident since the radiation is ubiquitous, characteristic of the isotopes present, and sufficiently penetrating so that measurements may be made remotely. However, save through detector proximity or minimal collimation, the directional nature of the radiation is generally not used in traditional nondestructive assay (NDA) measurements. To demonstrate the additional information available, we used GRIS, the Gamma-Ray Imaging Spectrometer, at the K-25 and Portsmouth gaseous diffusion plants. In this facility, UF{sub 6} gas is enriched in heated equipment and piping which run inside an insulated housing. Occasionally, the process develops uranium deposits due to leakage of wet air or environmental changes within the housing that cause solidification of the process gas. When such deposits occur, traditional NDA techniques frequently require costly and time-consuming entry within the heat shielding to obtain precise information on the deposit unavailable from outside the shielding. In this paper we discuss GRIS, the gamma-ray imaging technique it uses, and present the results of measurements obtained on fuel processing equipment.
Date: August 3, 1995
Creator: Ziock, K.P.; Madison, L. & McGinnis, B.R.
System: The UNT Digital Library
Near infra-red astronomy with adaptive optics and laser guide stars at the Keck Observatory (open access)

Near infra-red astronomy with adaptive optics and laser guide stars at the Keck Observatory

A laser guide star adaptive optics system is being built for the W. M. Keck Observatory`s 10-meter Keck II telescope. Two new near infra-red instruments will be used with this system: a high-resolution camera (NIRC 2) and an echelle spectrometer (NIRSPEC). The authors describe the expected capabilities of these instruments for high-resolution astronomy, using adaptive optics with either a natural star or a sodium-layer laser guide star as a reference. They compare the expected performance of these planned Keck adaptive optics instruments with that predicted for the NICMOS near infra-red camera, which is scheduled to be installed on the Hubble Space Telescope in 1997.
Date: August 3, 1995
Creator: Max, C. E.; Gavel, D. T. & Olivier, S. S.
System: The UNT Digital Library
Radiation drive in laser heated hohlraums (open access)

Radiation drive in laser heated hohlraums

Nearly 10 years of Nova experiments and analysis have lead to a relatively detailed quantitative and qualitative understanding of radiation drive in laser heated hohlraums. Our most successful quantitative modelling tool is 2D Lasnex numerical simulations. Analysis of the simulations provides us with insight into the details of the hohlraum drive. In particular we find hohlraum radiation conversion efficiency becomes quite high with longer pulses as the accumulated, high Z blow-off plasma begins to radiate. Extensive Nova experiments corroborate our quantitative and qualitative understanding.
Date: November 3, 1995
Creator: Suter, L.J.; Kauffman, R.L. & Darrow, C.B.
System: The UNT Digital Library
A comparison of national compliance legislation under the chemical weapons convention (open access)

A comparison of national compliance legislation under the chemical weapons convention

The Chemical Weapons Convention (CWC) is unique among multilateral arms control agreements in requiring national compliance legislation. This paper discusses the compliance legislation enacted by Australia, Germany, Norway, South Africa, and Sweden in anticipation of this agreement entering into force. It compares how these five nations addressed the requirement for legislation to penalize violations of the Convention, as well as how they have developed legal mechanisms to acquire the information about dual-use chemicals that must be declared to the Organisation for the Prohibition of Chemical Weapons. This analysis shows that although different options exist to meet these treaty requirements, areas of consistency between nations are emerging that will encourage universal compliance as the regime matures.
Date: March 3, 1995
Creator: Tanzman, E. A.
System: The UNT Digital Library