Microseismic monitoring of the Chaveroo oil field, New Mexico (open access)

Microseismic monitoring of the Chaveroo oil field, New Mexico

Microseismicity was monitored in the Chaveroo oil field in southeastern New Mexico during, and for 5 weeks following, a pressurized stimulation of a well being prepared as an injector for a water flood operation. Three-thousand barrels of water were injected into the reservoir over a 5.5-hour period. Little seismicity was detected during the stimulation. Intermittent monitoring over a 5-week period following the injection indicated detectable seismicity occurring with activity levels varying in time. The most active period recorded occurred just after production resumed in the immediate area of the monitor well. Mapping the microearthquakes using the hodogram technique indicates the events occur along linear trends which corroborate known structural trends of the field. Seismicity trends were defined both parallel and perpendicular to the regionally defined maximum horizontal stress direction. Seventy-three good quality events were recorded, in a cumulative 24 hour period, from which structures were mapped up to 3000 ft from the monitor well. 13 refs., 9 figs.
Date: February 6, 1990
Creator: Rutledge, J. T. & Albright, J. N.
Object Type: Article
System: The UNT Digital Library
A Source-to-Source Architecture for User-Defined Optimizations (open access)

A Source-to-Source Architecture for User-Defined Optimizations

The performance of object-oriented applications often suffers from the inefficient use of high-level abstractions provided by underlying libraries. Since these library abstractions are user-defined and not part of the programming language itself only limited information on their high-level semantics can be leveraged through program analysis by the compiler and thus most often no appropriate high-level optimizations are performed. In this paper we outline an approach based on source-to-source transformation to allow users to define optimizations which are not performed by the compiler they use. These techniques are intended to be as easy and intuitive as possible for potential users; i.e. for designers of object-oriented libraries, people most often only with basic compiler expertise.
Date: February 6, 2003
Creator: Schordan, M & Quinlan, D
Object Type: Article
System: The UNT Digital Library
Rheological Studies on Pretreated Feed and Melter Feed from AW-101 and AN-107 (open access)

Rheological Studies on Pretreated Feed and Melter Feed from AW-101 and AN-107

Rheological and physical properties testing were conducted on actual AN-107 and AW-101 pretreated feed samples prior to the addition of glass formers. Analyses were repeated following the addition of glass formers. The AN-107 and AW-101 pretreated feeds were tested at the target sodium values of nominally 6, 8, and 10 M. The AW-101 melter feeds were tested at these same concentrations, while the AN-107 melter feeds were tested at 5, 6, and 8 M with respect to sodium. These data on actual waste are required to validate and qualify results obtained with simulants.
Date: February 6, 2001
Creator: Bredt, Paul R. (BATTELLE (PACIFIC NW LAB)) & Swoboda, Robert G. (BATTELLE (PACIFIC NW LAB))
Object Type: Report
System: The UNT Digital Library
Metastable metallic hydrogen glass (open access)

Metastable metallic hydrogen glass

The quest for metallic hydrogen has been going on for over one hundred years. Before hydrogen was first condensed into a liquid in 1898, it was commonly thought that condensed hydrogen would be a metal, like the monatomic alkali metals below hydrogen in the first column of the Periodic Table. Instead, condensed hydrogen turned out to be transparent, like the diatomic insulating halogens in the seventh column of the Periodic Table. Wigner and Huntington predicted in 1935 that solid hydrogen at 0 K would undergo a first-order phase transition from a diatomic to a monatomic crystallographically ordered solid at {approx}25 GPa. This first-order transition would be accompanied by an insulator-metal transition. Though searched for extensively, a first-order transition from an ordered diatomic insulator to a monatomic metal is yet to be observed at pressures up to 120 and 340 GPa using x-ray diffraction and visual inspection, respectively. On the other hand, hydrogen reaches the minimum electrical conductivity of a metal at 140 GPa, 0.6 g/cm{sup 3}, and 3000 K. These conditions were achieved using a shock wave reverberating between two stiff sapphire anvils. The shock wave was generated with a two-stage light-gas gun. This temperature exceeds the calculated melting temperature …
Date: February 6, 2001
Creator: Nellis, W J
Object Type: Article
System: The UNT Digital Library
The National Ignition Facility (open access)

The National Ignition Facility

The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory is a stadium-sized facility containing a 192-beam, 1.8-Megajoule, 500-Terawatt, ultraviolet laser system together with a 10-meter-diameter target chamber and room for 100 diagnostics. NIF is the world's largest and most energetic laser experimental system, providing a scientific center to study inertial confinement fusion and matter at extreme energy densities and pressures. NIF's energetic laser beams will compress fusion targets to conditions required for thermonuclear burn, liberating more energy than required to initiate the fusion reactions. Other NIF experiments will study physical processes at temperatures approaching 10{sup 8} K and 10{sup 11} bar; conditions that exist naturally only in the interior of stars and planets. NIF has completed the first phases of its laser commissioning program. The first four beams of NIF have generated 106 kilojoules in 23-ns pulses of infrared light and over 16 kJ in 3.5-ns pulses at the third harmonic (351 nm). NIF's target experimental systems are being commissioned and experiments have begun. This paper provides a detailed look the NIF laser systems, laser and optical performance, and results from recent laser commissioning shots. We follow this with a discussion of NIF's high-energy-density and inertial fusion experimental capabilities, …
Date: February 6, 2004
Creator: Miller, G H; Moses, E I & Wuest, C R
Object Type: Article
System: The UNT Digital Library
Study of the Ionization Dynamics and Equation of State of a Strongly Coupled Plasma (open access)

Study of the Ionization Dynamics and Equation of State of a Strongly Coupled Plasma

Preliminary experiments to study the ionization dynamics and equation of state of a strongly coupled plasma have been performed at the LLNL COMET laser facility. In these experiment, a 1.0 J, 500 fs, 532 nm laser was used to create a uniform, warm dense plasma.The primary diagnostic, Fourier Domain Interferometry (FDI), was used to provide information about the position of the critical density of the target and thus the expansion hydrodynamics, laying the ground work for the plasma characterization. The plasmas were determined to be strongly coupled. In addition work was performed characterizing the back-lighter. A von Hamos spectrograph coupled to a 500 fs X-ray streak camera (TREX-VHS) developed at LLNL was used for these measurements. This diagnostic combines high collection efficiency ({approx} 10{sup -4} steradians) with fast temporal response ({approx} 500 fs), allowing resolution of extremely transient spectral variations. The TREX-VHS will be used to determine the time history, intensity, and spectral content of the back-lighter resulting in absorption measurements that provide insight into bound states in strongly coupled conditions.
Date: February 6, 2003
Creator: Shepherd, R; Audebert, P; Geindre, J P; Iglesias, C; Foord, M; Rogers, F et al.
Object Type: Report
System: The UNT Digital Library
PNNL DOE-Voluntary Protection Program (VPP) FY2003 Program Evaluation (open access)

PNNL DOE-Voluntary Protection Program (VPP) FY2003 Program Evaluation

This Program Evaluation report is an updated revision to the annual assessment of PNNL's VPP Program performance with respect to DOE-VPP criteria. It contains a summary of results and a data sheet for each of the VPP Elements, including strengths, weaknesses, recent/anticipated changes that will affect each Element, and a rating for each Element. Recommendations are also offered for continuous improvement.
Date: February 6, 2003
Creator: Wright, Patrick A.; Bowers, Harold N.; Madson, Vernon J.; Isern, Nancy G.; Collins, Drue A.; Haney, Janice M. et al.
Object Type: Report
System: The UNT Digital Library
The Kinetics of Phase Transformation in Welds (open access)

The Kinetics of Phase Transformation in Welds

The fundamentals of welding-induced phase transformations in metals and alloys are being investigated using a combination of advanced synchrotron based experimental methods and modem computational science tools. In-situ experimental methods have been developed using a spatially resolved x-ray probe to enable direct observations of phase transformations under the real non- isothermal conditions experienced during welding. These experimental techniques represent a major step forward in the understanding of phase transformations that occur during welding, and are now being used to aid in the development of models to predict microstructural evolution under the severe temperature gradients, high peak temperatures and rapid thermal fluctuations characteristic of welds. Titanium alloys, stainless steels and plain carbon steels are currently under investigation, and the phase transformation data being obtained here cannot be predicted or measured using conventional metallurgical approaches. Two principal synchrotron-based techniques have been developed and refined for in-situ investigations of phase transformation dynamics in the heat-affected zone (HAZ) and fusion zone (FZ) of welds: Spatially Resolved X-Ray Diffraction (SRXRD) and Time Resolved X-Ray Diffraction (TRXRD). Both techniques provide real-time observations of phases that exist during welding, and both have been developed at the Stanford Synchrotron Radiation Laboratory (SSRL) using a high flux wiggler beam …
Date: February 6, 2002
Creator: Elmer, J W; Wong, J & Palmer, T
Object Type: Report
System: The UNT Digital Library
Higher-Order Mixed Finite Element Methods for Time Domain Electromagnetics (open access)

Higher-Order Mixed Finite Element Methods for Time Domain Electromagnetics

This is the final report for LDRD 01-ERD-005. The Principal Investigator was Niel Madsen of the Defense Sciences Engineering Division (DSED). Collaborators included Daniel White, Joe Koning and Nathan Champagne of DSED, Mark Stowell of Center for Applications Development and Software Engineering (CADSE), and Ph.D. students Rob Rieben and Aaron Fisher at the UC Davis Department of Applied Science. It should be noted that the students were partially supported by the LLNL Student-Employee Graduate Research Fellow program. We begin with an Introduction which provides background and motivation for this research effort. Section II contains high-level description of our Approach, and Section III summarizes our key research Accomplishments. A description of the Software deliverables is provided in Section IV, and Section V includes simulation Validation and Results. It should be noted we do not get into the mathematical details in this report, rather these can be found in our publications which are listed in Section III.
Date: February 6, 2004
Creator: White, D; Stowell, M; Koning, J; Rieben, R; Fisher, A; Champagne, N et al.
Object Type: Report
System: The UNT Digital Library
Crystal level simulations using Eulerian finite element methods (open access)

Crystal level simulations using Eulerian finite element methods

Over the last several years, significant progress has been made in the use of crystal level material models in simulations of forming operations. However, in Lagrangian finite element approaches simulation capabilities are limited in many cases by mesh distortion associated with deformation heterogeneity. Contexts in which such large distortions arise include: bulk deformation to strains approaching or exceeding unity, especially in highly anisotropic or multiphase materials; shear band formation and intersection of shear bands; and indentation with sharp indenters. Investigators have in the past used Eulerian finite element methods with material response determined from crystal aggregates to study steady state forming processes. However, Eulerian and Arbitrary Lagrangian-Eulerian (ALE) finite element methods have not been widely utilized for simulation of transient deformation processes at the crystal level. The advection schemes used in Eulerian and ALE codes control mesh distortion and allow for simulation of much larger total deformations. We will discuss material state representation issues related to advection and will present results from ALE simulations.
Date: February 6, 2004
Creator: Becker, R; Barton, N R & Benson, D J
Object Type: Article
System: The UNT Digital Library
Modeling of High-Energy Pulsed Laser Interactions with Coupons (open access)

Modeling of High-Energy Pulsed Laser Interactions with Coupons

We describe a computational model of laser-materials interactions in the regime accessed by the solid state heat capacity lasers (SSHCLs) built at LLNL. We show that its predictions compare quite favorably with coupon experiments by the 10 kW SSHCL at LLNL. The body of this paper describes the following topics, listed by section number: (2) model in quiescent air, (3) comparison with experiments in quiescent air, (4) effects of air flow, (5) comparison with experiments involving air flow, (6) importance of material properties, (7) advantage of pulsed lasers over CW lasers, and (8) conclusions and recommendations.
Date: February 6, 2003
Creator: Boley, C D & Rubenchik, A M
Object Type: Report
System: The UNT Digital Library
Managing the Arroyo Seco for Flood Prevention, Erosion Control, Waterway and Habitat Restoration (open access)

Managing the Arroyo Seco for Flood Prevention, Erosion Control, Waterway and Habitat Restoration

One of the most important tasks for a site facility manager is to ensure that appropriate channel erosion controls are applied to on-site drainage channels. These erosion controls must minimize risks to the public and structures. Water and sediment loads commonly originate from off-site sources and many of the traditional reactionary measures (installing rip-rap or some other form of bed or bank armor) simply transfer or delay the problem. State and federal agency requirements further complicate the management solution. One case in point is the Arroyo Seco, an intermittent stream that runs along the southwest corner of the Lawrence Livermore National Laboratory (LLNL) in Livermore, California. In 2001, LLNL contracted Questa Engineering Corporation to conduct hydraulic, geomorphic, and biological investigations and to prepare an alternatives and constraints analysis. From these investigations, LLNL has selected a water management plan that encompasses overall flood prevention, erosion control, and waterway and habitat restoration and enhancement elements. The most unique aspect of the Arroyo Seco management plan is its use of non-traditional and biotechnical techniques.
Date: February 6, 2003
Creator: Sanchez, L; Wang, C & Laurant, J
Object Type: Article
System: The UNT Digital Library
Hadean Oceanography: Experimental Constraints on the Development of the Terrestrial Hydrosphere and the Origin of Life on Earth (open access)

Hadean Oceanography: Experimental Constraints on the Development of the Terrestrial Hydrosphere and the Origin of Life on Earth

The oxygen isotopic compositions of the world's oldest mineral grains, zircon, have recently been used to infer the compositions of the rocks from which they crystallized. The results appear to require a source that had once experienced isotopic fractionation between clay minerals and liquid water, thereby implying the presence of liquid water at the Earth's surface prior to 4.4 billion years ago, less than 2 million years after accretion. This observation has important implications for the development of the Earth's continental crust. The inferred composition of the zircon source rock is directly dependent upon the oxygen isotopic fractionation between zircon and melt, and zircon and water. These fractionation factors have not been determined experimentally, however, constituting the weak link in this argument. A series of experiments to measure these fractionation factors has been conducted. The experiments consist of finely powdered quartz, a polished single crystal of zircon and isotopically-enriched or isotopically normal water to provide a range of isotopic compositions. The experiments will be run until quartz is in isotopic equilibrium with water. Zircon was expected to partially equilibrate producing an oxygen isotopic diffusion profile perpendicular to the surface. Ion probe spot analysis of quartz and depth profiling of zircon …
Date: February 6, 2003
Creator: Ryerson, F J
Object Type: Report
System: The UNT Digital Library
Speech Articulator and User Gesture Measurements Using Micropower, Interferometric EM-Sensors (open access)

Speech Articulator and User Gesture Measurements Using Micropower, Interferometric EM-Sensors

Very low power, GHz frequency, ''radar-like'' sensors can measure a variety of motions produced by a human user of machine interface devices. These data can be obtained ''at a distance'' and can measure ''hidden'' structures. Measurements range from acoustic induced, 10-micron amplitude vibrations of vocal tract tissues, to few centimeter human speech articulator motions, to meter-class motions of the head, hands, or entire body. These EM sensors measure ''fringe motions'' as reflected EM waves are mixed with a local (homodyne) reference wave. These data, when processed using models of the system being measured, provide real time states of interface positions or other targets vs. time. An example is speech articulator positions vs. time in the user's body. This information appears to be useful for a surprisingly wide range of applications ranging from speech coding synthesis and recognition, speaker or object identification, noise cancellation, hand or head motions for cursor direction, and other applications.
Date: February 6, 2001
Creator: Holzrichter, J F & Ng, L C
Object Type: Article
System: The UNT Digital Library
Explosion-induced combustion of hydrocarbon clouds in a chamber (open access)

Explosion-induced combustion of hydrocarbon clouds in a chamber

The interaction of the detonation of a solid HE-charge with a non-premixed cloud of hydro-carbon fuel in a chamber was studied in laboratory experiments. Soap bubbles filled with a flammable gas were subjected to the blast wave created by the detonation of PETN-charges (0.2 g < mass < 0.5 g). The dynamics of the combustion system were investigated by means of high-speed photography and measurement of the quasi-static chamber pressure.
Date: February 6, 2001
Creator: Neuwald, P; Reichenbach, H & Kuhl, A L
Object Type: Article
System: The UNT Digital Library
Satellite-based Observation of the Tectonics of Southern Tibet (open access)

Satellite-based Observation of the Tectonics of Southern Tibet

The Himalayas and the Tibetan Plateau were formed as a result of the collision of India and Asia, and provide an excellent natural laboratory for the investigation of the mechanical response of the outer 100 km of the Earth (the lithosphere) to tectonic stress. Geophysicists are divided in their views on the nature of this response with one group advocating homogeneously distributed deformation in which the lithosphere deforms as a fluid continuum while others contend that deformation is highly localized with the lithosphere deforming as a system of rigid blocks. These rigid blocks or plate undergo little internal deformation. The latter group draws support from the high slip-rates recently observed on strike-slip faults along the northern edge of the Plateau (the Altyn Tagh Fault, ATF), coupled with seismic observations suggesting that these faults penetrate the entire lithosphere. These ''lithospheric faults'' define continental lithospheric plates and facilitate the eastward extrusion of the ''central Tibet plate''. If extrusion of a rigid Tibet occurs then there must be equivalent features at its southern boundary with slip-rates similar to those in the north. The southern boundary of Tibet, defined by the Main Himalayan Thrust (MHT), has no lateral component of motion and is therefore …
Date: February 6, 2003
Creator: Ryerson, F J; Finkel, R & van der Woerd, J
Object Type: Report
System: The UNT Digital Library
Simulations of shock-induced mixing& combustion of an acetylene cloud in a chamber (open access)

Simulations of shock-induced mixing& combustion of an acetylene cloud in a chamber

In this paper we present numerical simulations of the interaction of a blast wave with an acetylene bubble in a closed chamber. We model the system using the inviscid Euler equations for a mixture of ideal gases. The formulation specifies the thermodynamic behavior of the system using a Chemkin interface and includes the capability to model combustion as the ambient air mixes with the acetylene. The simulations are performed using a three-dimensional adaptive mesh refinement algorithm based on a second-order Godunov integration scheme. Simulations are compared with experimental measurements for the same configuration.
Date: February 6, 2001
Creator: Bell, J B; Day, M S; Beckner, V E; Kuhl, A L; Neuwald, P & Reichenbach, H
Object Type: Article
System: The UNT Digital Library
Mixing-controlled exothermic fields in explosions (open access)

Mixing-controlled exothermic fields in explosions

A theoretical model of combustion in explosions at large Reynolds, Peclet and Damkoehler numbers is described. A key feature of the model is that combustion is treated as material transformations in the Le Chatelier state plane, rather than ''heat release''. In the limit considered here, combustion is concentrated on thin exothermic sheets (boundaries between fuel and oxidizer). The products seem to expand along the sheet, thereby inducing vorticity on either side of the sheet that continues to feed the process. The results illustrate the linking between turbulence (vorticity) and exothermicity (dilatation) in the limit of fast chemistry--thereby demonstrating the controlling role that fluid dynamics plays in such problems.
Date: February 6, 2001
Creator: Kuhl, A L; Oppenheim, A K & Ferguson, R E
Object Type: Article
System: The UNT Digital Library
Metallurgy and Ceramics/Superplasticity in Metals and Ceramics (open access)

Metallurgy and Ceramics/Superplasticity in Metals and Ceramics

In the past three years, we have carried out a number of studies on the deformation and superplasticity of fine-structured materials. The goal was to develop an understanding on the deformation microstructure relationship in these advanced materials and to improve further their properties through microstructural control. In this report, we describe only some of the key results and observations from these studies.
Date: February 6, 2002
Creator: Nieh, T G
Object Type: Report
System: The UNT Digital Library
Ultra-wideband Communications (open access)

Ultra-wideband Communications

Many applications in wireless communications often require short-range systems capable of rapidly collecting data and transmitting it reliably. Commercial communication systems operate in fixed frequency bands and are easily detectable and are prone to jamming by the enemy, among other shortcomings. The new ultra-wideband (UWB) communications system in the 3.1 to 10 GHz band is of significant interest to a number of Lawrence Livermore National Laboratory (LLNL) programs including the Nonproliferation, Arms Control, and International Security (NAI) Directorate. Ultra-Wideband (UWB) technology has received a significant degree of attention from communications industry since the Federal Communications Commission (FCC) rulings in February 2002. According to FCC, UWB signals have fractional bandwidth (B{sub f}) of 20% or larger at -10 dB cut-off frequencies, with minimum bandwidth of 500 MHz. Unlike traditional communication systems, UWB systems modulate carrier-less, short-duration (picosec to nanosec) pulses to transmit and receive information. A number of programmatic problems at LLNL, particularly in the NAI and other national security Directorates, require collecting information from multiple sensors distributed over a local area. The information must be collected covertly and by wireless means. The sensors produce data using low power devices and the communication link must operate in severe multipath environments over …
Date: February 6, 2004
Creator: Waltjen, K.; Romero, C.; Azevedo, S.; Dowla, F.; Spiridon, A.; Benzel, D. et al.
Object Type: Report
System: The UNT Digital Library
Coral Radiocarbon Records of Indian Ocean Water Mass Mixing and Wind-Induced Upwelling Along the Coast of Sumatra, Indonesia (open access)

Coral Radiocarbon Records of Indian Ocean Water Mass Mixing and Wind-Induced Upwelling Along the Coast of Sumatra, Indonesia

Radiocarbon ({sup 14}C) in the skeletal aragonite of annually banded corals track radiocarbon concentrations in dissolved inorganic carbon (DIC) in surface seawater. As a result of nuclear weapons testing in the 1950s, oceanic uptake of excess {sup 14}C in the atmosphere has increased the contrast between surface and deep ocean {sup 14}C concentrations. We present accelerator mass spectrometric (AMS) measurements of radiocarbon isotope ({Delta}{sup 14}C) in Porites corals from the Mentawai Islands, Sumatra (0 S, 98 E) and Watamu, Kenya (3 S, 39 E) to document the temporal and spatial evolution of the {sup 14}C gradient in the tropical Indian Ocean. The rise in {Delta}{sup 14}C in the Sumatra coral, in response to the maximum in nuclear weapons testing, is delayed by 2-3 years relative to the rise in coral {Delta}{sup 14}C from the coast of Kenya. Kenya coral {Delta}{sup 14}C values rise quickly because surface waters are in prolonged contact with the atmosphere. In contrast, wind-induced upwelling and rapid mixing along the coast of Sumatra entrains {sup 14}C-depleted water from the subsurface, which dilutes the effect of the uptake of bomb-laden {sup 14}C by the surface-ocean. Bimonthly AMS {Delta}{sup 14}C measurements on the Mentawai coral reveal mainly interannual variability …
Date: February 6, 2004
Creator: Guilderson, T. P.; Grumet, N. S.; Abram, N. J.; Beck, J. W.; Dunbar, R. B.; Gagan, M. K. et al.
Object Type: Article
System: The UNT Digital Library
Final Report for LDRD Project 02-ERD-069: Discovering the Unknown Mechanism(s) of Virulence in a BW, Class A Select Agent (open access)

Final Report for LDRD Project 02-ERD-069: Discovering the Unknown Mechanism(s) of Virulence in a BW, Class A Select Agent

The goal of this proposed effort was to assess the difficulty in identifying and characterizing virulence candidate genes in an organism for which very limited data exists. This was accomplished by first addressing the finishing phase of draft-sequenced F. tularensis genomes and conducting comparative analyses to determine the coding potential of each genome; to discover the differences in genome structure and content, and to identify potential genes whose products may be involved in the F. tularensis virulence process. The project was divided into three parts: (1) Genome finishing: This part involves determining the order and orientation of the consensus sequences of contigs obtained from Phrap assemblies of random draft genomic sequences. This tedious process consists of linking contig ends using information embedded in each sequence file that relates the sequence to the original cloned insert. Since inserts are sequenced from both ends, we can establish a link between these paired-ends in different contigs and thus order and orient contigs. Since these genomes carry numerous copies of insertion sequences, these repeated elements ''confuse'' the Phrap assembly program. It is thus necessary to break these contigs apart at the repeated sequences and individually join the proper flanking regions using paired-end information, or …
Date: February 6, 2003
Creator: Chain, P & Garcia, E
Object Type: Report
System: The UNT Digital Library
Radiative Strength Functions in 172yb Below 8 Me V (open access)

Radiative Strength Functions in 172yb Below 8 Me V

We have measured prompt {gamma} rays after thermal and resonant neutron capture in {sup 171}Yb. The {gamma} rays were measured with three high resolution ({approx}3 keV) and high efficiency (two {approx}80% Ge(HP) and one {approx}200% segmented Clover) detectors. We have obtained singles and two-fold coincidence spectra as function of neutron energy using the time-of-flight technique. Two-fold coincidences where the summed energy adds up to the neutron binding energy B{sub n} or to B{sub n} minus the energy of the first excited stated ({approx}79 keV) will be used to determine the multipolarity of the pygmy resonance in {sup 172}Yb. This pygmy resonance is a resonant structure in the radiative strength function around {approx}3 MeV in deformed rare earth nuclei [1]. The following goals were met: (1) We have shown the feasibility of prompt, high-resolution {gamma} spectroscopy at FP14 after thermal as well as resonant neutron capture. (2) Online analysis shows that sufficient statistics ({approx}7000 counts) are expected in each of the two relevant peaks in the summed-energy spectrum. Analysis of the experiment is in progress. It still remains to show that the multipolarity of the pygmy resonance can be determined experimentally from two-step cascade intensities.
Date: February 6, 2002
Creator: Schiller, A.; Becker, J. A.; Bernstein, L. A.; Garrett, P. E.; Hill, T. S.; McNabb, D. P. et al.
Object Type: Report
System: The UNT Digital Library
PROGRESS REPORT FOR DECEMBER 1944 (open access)

PROGRESS REPORT FOR DECEMBER 1944

None
Date: February 6, 1945
Creator: Gray, A G & Thompson, J G
Object Type: Report
System: The UNT Digital Library