69 Matching Results

This system will be undergoing maintenance April 18th between 9:00AM and 12:00PM CDT.

Search Results

Advanced search parameters have been applied.
in creator/contributor: "Edwards, D."  
Results: 1 - 24 next
open access

Position and profile of a multiampere proton beam

Description: The spacial profile of a bunched or unbunched proton beam may be found by using a highly collimated molecular beam of N/sub 2/. A certain fraction of the molecular N/sub 2/ will be ionized as it crosses the proton beam. By measuring the N/sub 2//sup +/ current as a function of theta the cross section of the beam is directly obtained. As an example, a 10 A proton beam of diameter 1 mm is considered.
Date: October 20, 1977
Creator: Edwards, D. Jr.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Interrupted pumpdown of a vacuum system

Description: The pressure rise due to a surface outgassing process following a real pump closure has been analyzed and found under a physically reasonable parameter selection to occur very quickly yet result in a very slight actual pressure change. Real leaks thus should be able to be able to be distinguished from surface outgassing processes by this technique.
Date: January 1, 1980
Creator: Edwards, D Jr
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Neutral molecule desorption from SS(304) and Al(6061) due to particle bombardments

Description: The pressure in both electron and proton storage rings is dependent on the particle wall bombardment molecular desorption rates due in one case (proton storage rings) to approx. keV ions while in the other to approx. 100 eV electrons. Also in order to minimize secondary electron amplification effects in both types of machines the secondary electron emission coefficient should be as low as possible. The above quantities have been measured on Al(6061) and SS(304) materials having had various trea… more
Date: January 1, 1979
Creator: Edwards, D. Jr.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Raman scattering in crystals

Description: A tutorial presentation is given of Raman scattering in crystals. The physical concepts are emphasized rather than the detailed mathematical formalism. Starting with an introduction to the concepts of phonons and conservation laws, the effects of photon-phonon interactions are presented. This interaction concept is shown for a simple cubic crystal and is extended to a uniaxial crystal. The correlation table method is used for determining the number and symmetry of the Raman active modes. Finall… more
Date: September 30, 1988
Creator: Edwards, D.F.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Very small ionization pressure gauge

Description: A very small ionization pressure gauge has been developed to operate in the pressure range 10/sup -6/ Torr to 100..mu... A metal construction and external cooling fins result in a very rugged device with exceptionally small outgassing properties. The gauge also incorporates a replaceable filament-grid assembly on a single plug which allows the simple replacement of both the filament and the grid when needed.
Date: January 1, 1982
Creator: Edwards, D. Jr.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Ion and electron desorption of neutral molecules from SS (304)

Description: The vacuum performance of both electron and proton storage rings (as well as certain types of fusion reactors) is expected to be sensitive to the desorption of neutral molecules from the vacuum chamber wall by approx. keV charged particles. In this study the desorption yields of H/sub 2/, CO, CO/sub 2/, and CH/sub 4/ are reported for 1000 eV Ar/sup +/ and 500 eV e/sup -/ impacting on SS (304) samples (approx. 1000 cm/sup 2/ surface area) prepared by: (1) standard degrease treatment, (2) an acid… more
Date: January 1, 1978
Creator: Edwards, D. Jr.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Heat of vaporization spectrometer

Description: Multilayer desorption measurements of various substances adsorbed on a stainless steel substrate are found to exhibit desorption profiles consistent with a zeroth order desorption model. The singleness of the desorption transients together with their narrow peak widths makes the technique ideally suited for a heat of vaporization spectrometer for either substance analysis or identification.
Date: January 1, 1978
Creator: Edwards, D. Jr.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Upper bound to the pressure in an elementary vacuum system

Description: A vacuum system consisting of a volume V, a pump S and a surface area A on which there are initially adsorbed n(0) molecules in a first order desorption state is considered and discussed. The essential result is that P/sub max/ = 1.146 x 10/sup -5/ A/St torr is expected to provide a reasonably accurate estimate for the value the pressure should be strictly less than t seconds after the pumping has started given that the pressure in the system is due to an adsorbed surface phase. Experimental te… more
Date: January 1, 1976
Creator: Edwards, D., Jr.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Vacuum guidelines for ISA insertions

Description: Vacuum requirements place design restrictions on the ISA insertions. The vacuum tube diameter, given a distance L between pumps, is determined by the desorption of molecules from the wall under the impact of ions created by the beam, whereas the thickness of the tube must be sufficient to prevent collapse. In addition, the entire vacuum chamber must be able to be baked out at approximately 200/sup 0/C.
Date: January 1, 1976
Creator: Edwards, D. Jr.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Nitrogen pressure in a vacuum system

Description: Since the N/sub 2/ outgassing rate from walls of a vacuum system is generally recognized to be very small, the presence of a N/sub 2/ pressure in the system is a useful indication of the presence of real leaks to the atmosphere. A technique of thermal desorption mass spectrometry is introduced which allows the N/sub 2/ pressure in the background gas of a baked system to be separated from a CH/sub 4/ background to a minimum level of N/sub 2/ detectability of approximately 1 percent of the CO bac… more
Date: January 1, 1977
Creator: Edwards, D. Jr.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Water vapor pressure gauge

Description: An inexpensive pressure gauge, able to measure the N/sub 2/ and H/sub 2/O components within a vacuum system in the pressure range 1..mu.. to 400..mu.. is described and results of tests of the device are reported.
Date: January 1, 1980
Creator: Edwards, D Jr & Gillette, D
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

High-precision multipass reflectometer

Description: The multipass reflectometer has been shown to be a convenient and precise instrument for the measurement of spectral reflectances in excess of 0.99. This report gives a brief sketch of the initial setup of the reflectometer, its operation, optimization of parameters, and some limitations to the expected precision. The instrumental precision is set by the uncertainty in the computer fit of a straight line to the measured data. Systematic errors due to nonuniform photosurfaces and the effects of … more
Date: January 1, 1981
Creator: Edwards, D.F. & Baumeister, P.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Trace impurity analyzer

Description: The desirability for long-term reliability of large scale helium refrigerator systems used on superconducting accelerator magnets has necessitated detection of impurities to levels of a few ppM. An analyzer that measures trace impurity levels of condensable contaminants in concentrations of less than a ppM in 15 atm of He is described. The instrument makes use of the desorption temperature at an indicated pressure of the various impurities to determine the type of contaminant. The pressure rise… more
Date: January 1, 1979
Creator: Schneider, W. J. & Edwards, D. Jr.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Improved aluminum coatings for the ultraviolet

Description: Highly reflective aluminum coatings or aluminum coatings with dielectric overcoats are frequently used in the ultraviolet. The reflectance values published by Hass and his group are generally accepted for this uv region. We have produced evaporated aluminum coatings for a wide range of deposition conditions and none of our coatings exhibit the Hass reflectance characteristics. The reflectance of our coatings appear to be independent of the evaporation pressure and deposition time or rate. Our c… more
Date: January 1, 1981
Creator: Edwards, D.F.; LaDelfe, P. & Ochoa, E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Ion desorption test instrument

Description: An instrument is described which allows the determination of the number of CO molecules released from a surface and equilibrating into the gas phase when an approximately 1000 eV argon ion strikes a metal wall. Evidence is reported on an enhancement of the CO outgassing rate due to ion bombardment. The above measurements are of significance in the design of high intensity proton storage rings as well as in characterizing a first wall process in fusion reactors.
Date: January 1, 1977
Creator: Edwards, D. Jr.; Halama, H. & Aggus, J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

THE VAPOR PRESSURES OF 30 INORGANIC LIQUIDS BETWEEN ONE ATMOSPHERE AND THE CRITICAL POINT

Description: Literature values of the vapor pressures of H/sub 2/, HD, D/sub 2/, N/ sub 2/, O/sub 2/, Ne, Ar, Kr, Xe, CO, NO, CH/sub 4/, N/sub 2/O, CO/sub 2/, HCl HBr, HI, SF/sub 6/, H/sub 2/S, Cl/sub 2/, Br/sub 2/, NH/sub 3/, C/sub 2/H/sub 2/ , SO/sub 2/, SO/sub 3/, COCl/sub 2/, HF, HCN, N/sub 2/O/sub 4/, CCl/sub 4/, and SnCl/sub 4/ were compared with the Kirchhoff formula log PK = --A/T + B between the normal boiling point and the critical point, where A and B are determined for each liquid. Plots are pre… more
Date: June 13, 1963
Creator: Edwards, D.G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Characterization of optical surface degradation: Angular resolved scatterometer

Description: The Angular Resolved Scatterometer (ARS) is a sensitive diagnostic instrument for quantitatively specifying the degree of degradation for optical surfaces. ARS test results are reported for coatings undergoing aboveground (AGT) prompt x-ray irradiation. With the ARS, the light scattered from an optical surface is measured as a function of scattering angle, wavelength, and polarization. From these data the power spectral density (PSD) is calculated and contains the bandwidth-limited spatial info… more
Date: February 26, 1987
Creator: Edwards, D.F.; Gillespie, C.H. & Wirtenson, G.R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Factors determining the choice of the beam tube material and the vacuum chamber design for a superconducting high energy storage accelerator

Description: The factors which determine the choice of the material and the basic design for the vacuum chamber of the ISABELLE Colliding Storage Accelerator are reviewed. When the physical, thermal, electrical, and mechanical properties of the bulk material, as well as the various surface characteristics, are considered, it appears that a stainless tube covered with a copper sleeve is the best choice for the chambers in the magnet lattice of the rings. Aluminum is probably the most desirable material for t… more
Date: January 1, 1979
Creator: Aggus, J.; Edwards, D. Jr.; Halama, H.J. & Herrera, J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

An rf separated kaon beam from the Main Injector: Superconducting aspects

Description: ThE report is intended to focus on the superconducting aspects of a potential separated kaon beam facility for the Main Injector, and most of this document reflects that emphasis. However, the RF features cannot be divorced from the overall beam requirements, and so the next section is devoted to the latter subject. The existing optics design that meets the needs of the two proposed experiments is outliied, and its layout at Fermilab is shown. The frequency and deflection gradient choices prese… more
Date: November 1, 1998
Creator: Edwards, D. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Parameter selection for the SSC trade-offs and optimization

Description: In November of 1988, a site was selected in the state of Texas for the SSC. In January of 1989, the SSC Laboratory was established in Texas to adapt the design of the collider to the site and to manage the construction of the project. This paper describes the evolution of the SSC design since site selection, notes the increased concentration on the injector system, and addresses the rationale for choice of parameters.
Date: October 14, 1991
Creator: Edwards, D. A. & Syphers, M. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Polarized RF guns for linear colliders: An ICFA Workshop

Description: The ICFA Workshop on Polarized RF Guns for Linear Colliders was held at Fermilab during April 18-20, 2001. It was attended by 37 scientists from 14 institutions. A list of participants is appended. An RF photoemission gun that delivers polarized electrons at low emittance would be an attractive electron source for a linear collider. Moreover, recently it has been demonstrated that an RF gun in conjunction with nearby injection system optics can deliver a beam with a high ratio of transverse emi… more
Date: January 31, 2002
Creator: Edwards, D. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Interfacial shear modeling in two-phase annular flow

Description: A new interfacial shear stress model called the law of the interface model, based on the law of the wall approach in turbulent flows, has been developed and locally applied in a fully developed, adiabatic, two-phase annular flow in a duct. Numerical results have been obtained using this model in conjunction with other models available in the literature that are required for the closure of the continuity and momentum equations. These results have been compared with droplet velocity data (using l… more
Date: July 1, 1996
Creator: Kumar, R. & Edwards, D.P.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
Back to Top of Screen