Recent advances in phosphate laser glasses for high power applications (open access)

Recent advances in phosphate laser glasses for high power applications

Recent advances in Nd-doped phosphate laser glasses for high-peak-power and high-average-power applications are reviewed. Compositional studies have progressed to the point that glasses can be tailored to have specific properties for specific applications. Non-radiative relaxation effects can be accurately modeled and empirical expressions have been developed to evaluate both intrinsic (structural) and extrinsic (contamination induced) relaxation effects. Losses due to surface scattering and bulk glass absorption have been carefully measured and can be accurately predicted. Improvements in processing have lead to high damage threshold (e.g. Pt inclusion free) and high thermal shock resistant glasses with improved edge claddings. High optical quality pieces up to 79 x 45 x 4cm{sup 3} have been made and methods for continuous melting laser glass are under development.
Date: May 14, 1996
Creator: Campbell, J.H.
Object Type: Article
System: The UNT Digital Library
AGS Modifications for High Transition Energy (open access)

AGS Modifications for High Transition Energy

This report addresses the AGS modifications for high transition energy
Date: May 14, 1996
Creator: D., Courant E. & Trbojevic, D.
Object Type: Report
System: The UNT Digital Library
Enhanced research in ground-penetrating radar and multisensor fusion with application to the detection and visualization of buried waste. Final report (open access)

Enhanced research in ground-penetrating radar and multisensor fusion with application to the detection and visualization of buried waste. Final report

Recognizing the difficulty and importance of the landfill remediation problems faced by DOE, and the fact that no one sensor alone can provide complete environmental site characterization, a multidisciplinary team approach was chosen for this project. The authors have developed a multisensor fusion approach that is suitable for the wide variety of sensors available to DOE, that allows separate detection algorithms to be developed and custom-tailored to each sensor. This approach is currently being applied to the Geonics EM-61 and Coleman step-frequency radar data. High-resolution array processing techniques were developed for detecting and localizing buried waste containers. A soil characterization laboratory facility was developed using a HP-8510 network analyzer and near-field coaxial probe. Both internal and external calibration procedures were developed for de-embedding the frequency-dependent soil electrical parameters from the measurements. Dispersive soil propagation modeling algorithms were also developed for simulating wave propagation in dispersive soil media. A study was performed on the application of infrared sensors to the landfill remediation problem, particularly for providing information on volatile organic compounds (VOC`s) in the atmosphere. A dust-emission lidar system is proposed for landfill remediation monitoring. Design specifications are outlined for a system which could be used to monitor dust emissions in …
Date: May 14, 1996
Creator: Devney, A. J.; DiMarzio, C.; Kokar, M.; Miller, E. L.; Rappaport, C. M. & Weedon, W. H.
Object Type: Report
System: The UNT Digital Library
Measurement of emission diameter as a function of time on foam z- pinch plasmas (open access)

Measurement of emission diameter as a function of time on foam z- pinch plasmas

We have developed a streaked imaging capability to make time-resolved measurements of the emission size for low density foam z-pinches. By lens coupling visible emission from the z-pinch target to an array of fiber optics we obtained the emission profile in the visible as a function of time with radial resolution of 300 {mu}m. To measure the emission at temperatures greater than {approx}40 eV the source was slit-imaged or pin-hole imaged onto an x-ray filtered scintillator. Non-uniformities in both visible and x-ray emission were observed. We describe the diagnostics, the image unfold process, and results from the instrument for both visible and x-ray measurements.
Date: May 14, 1996
Creator: Lazier, S. E.; Barber, T. L.; Derzon, M. S. & Kellogg, J. W.
Object Type: Article
System: The UNT Digital Library
Evaluation of tropospheric water vapor profiling using eye-safe, infrared differential absorption lidar (open access)

Evaluation of tropospheric water vapor profiling using eye-safe, infrared differential absorption lidar

Continuous, high quality profiles of water vapor, free of systematic bias, and of moderate temporal and spatial resolution are fundamental to the success of the ARM CART program. In addition, these should be acquired over long periods at low operational and maintenance cost. The development and verification of realistic climate model parameterizations for clouds and net radiation balance, and the correction of other CART site sensor observations for interferences due to the presence of water vapor are critically dependent on water vapor profile measurements. To date, application of profiles have been limited by vertical resolution and uniqueness and high operating cost, or diminished daytime performance, lack of eye-safety, and high maintenance cost. Recent developments in infrared laser and detector technology make possible compact IR differential absorption lidar (DIAL) systems at eye-safe wavelengths. In the studies reported here, we develop DIAL system performance models and examine the potential of solving some of the shortcomings of previous methods using parameters representative of current technologies. These simulations are also applied to determine the strengths and weaknesses unique to the DIAL method for this application.
Date: May 14, 1996
Creator: Rye, B. J.; Machol, J. L.; Grund, C. J. & Hardesty, R. M.
Object Type: Report
System: The UNT Digital Library
D0 Silicon Upgrade: Muon Shield Conceptual Design Report (open access)

D0 Silicon Upgrade: Muon Shield Conceptual Design Report

The nominal overall dimensions are 71-inch high x 71-inch wide x 144-inch long and has a 25-inch square hole throughout. The shield consists of three different materials, steel (inner most section), polycarbonate (central section) and lead (outer most section). The material thicknesses are, steel=15-inch, poly=6-inch and lead=2-inch. The estimated weight is {approx}69 tons. The shield is centered about the Tev beam line and the 25-inch square hole provides clearance to the low Beta quad, which is nominally 20-inch square. During beamline operation, the shield is in contact with Samus magnet core at the detector end and with the Main Ring shield wall on the MR side (with some small clearance {approx}2-inch-3-inch). The need for the clearance will be discussed later. The shield support structure consists steel structural members appropriately sized for loads encountered in the design. The structure must not only support the shield but, must be designed for rolling the entire assembly into position in the collision hall. It must provide for cylinders to lift the assembly, Hilman rollers and also connections for moving the entire assembly. The movement is considered to be similar to that with which the calorimeters were moved from the clean room to the sidewalk …
Date: May 14, 1996
Creator: Stredde, Herman J.
Object Type: Report
System: The UNT Digital Library
Impurity effects on bonding charge in Ni{sub 3}Al (open access)

Impurity effects on bonding charge in Ni{sub 3}Al

We have studied the effect of B and H on the charge density in Ni{sub 3}Al employing first-principles electronic structure calculations based on the FLMTO method. The changes in the electronic structure induced by B result from hybridization of d states of the nearest neighbor Ni atoms with adjacent B-{ital PP} states. Thus, boron prefers to occupy Ni-rich octahedral interstices [X(7)]. Boron greatly enhances the intraplanar metallic bonding between the Ni atoms, enhances the interplanar bonding between the NiAl layers in [001] direction, and reduces the bonding-charge directionality near the Ni(3) atoms. It is concluded that B acts to increase crystal cohesion. Hydrogen enhances the bonding-charge directionality near Ni(3) atoms and has virtually no interstitial charge enhancement, suggesting that H does not promote local cohesion. When both B and H are present, the dominant changes in the electronic structure induced by B and H seems to have little effect.
Date: May 14, 1996
Creator: Sun, Sheng N.; Kioussis, N.; Lim, Say-Peng; Gonis, A. & Gourdin, W.
Object Type: Article
System: The UNT Digital Library
Use of thin wall imaging in the diagnosis of laser heated hohlraums (open access)

Use of thin wall imaging in the diagnosis of laser heated hohlraums

High-Z, laser heated hohlraums can be made thick enough to contain thermal radiation, yet thin enough to let out x-rays >{approximately}6keV produced by hot, relatively dense blow-off plasma. The authors use such ``thin wall hohlraums`` to observe the physical location of hot, dense, laser produced hohlraum plasmas. This technique has allowed them to come to some understanding of laser transport/deposition, plasma stagnation and bulk plasma filling.
Date: May 14, 1996
Creator: Suter, L.J.; Thiessen, A.R.; Ze, F.; Kauffman, R.; Price, R.H.; Rupert, V.C. et al.
Object Type: Article
System: The UNT Digital Library