27,216 Matching Results

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A 0. 5 to 3. 0 MeV monoenergetic positron beam (open access)

A 0. 5 to 3. 0 MeV monoenergetic positron beam

An adjustable, 0.5--3 MeV monoenergetic positron beam has been constructed at Brookhaven. Currently a /sup 22/Na source with a W(100) foil transmission moderator produces a 1.1 mm FWHN beam with an intensity of 3/times/10/sup 5/ e/sup +//sec at a target located downstream from the accelerator. The divergence of the beam is less than 0.1/degree/ at 2.2 MeV energy. A SOA gun with 2 lens transport system brings the beam to a focus at the entrance of an electrostatic 3 MeV Dynamitron accelerator. The post acceleration beam transport system comprises 3 focusing solenolds, 4 sets of steering magnets and a 90/degree/ double focusing bending magnet. The beam energy spread at the target is <1 keV FWHN deduced from the beam size. Below we describe the positron extraction optics and acceleration, the construction of the beamline and the beam diagnostic devices. The salient beam parameters are listed at the end of this paper. 2 refs., 3 figs., 1 tab.
Date: 1988~
Creator: Huomo, H.; AsokaKumar, P.; Henderson, S. D.; Phlips, B. F.; Mayer, R.; McDonough, J. et al.
Object Type: Article
System: The UNT Digital Library
The 0/sup +/ /minus/ 1/sup +/ A = 4. lambda. -hypernuclei binding energy difference in an exact equation, separable potential calculation (open access)

The 0/sup +/ /minus/ 1/sup +/ A = 4. lambda. -hypernuclei binding energy difference in an exact equation, separable potential calculation

None
Date: January 1, 1988
Creator: Gibson, B. F. & Lehman, D. R.
Object Type: Article
System: The UNT Digital Library
1-D closure models for slender 3-D viscoelastic free jets: von Karman flow geometry and elliptical cross section (open access)

1-D closure models for slender 3-D viscoelastic free jets: von Karman flow geometry and elliptical cross section

In this paper we derive one space dimensional, reduced systems of equations (1-D closure models) for viscoelastic free jets. We begin with the three-dimensional system of conservation laws and a Maxwell-Jeffreys constitutive law for an incompressible viscoelastic fluid. First, we exhibit exact truncations to a finite, closed system of 1-D equations based on classical velocity assumptions of von Karman. Next, we demonstrate that the 3-D free surface boundary conditions overconstrain these truncated systems, so that only a very limited class of solutions exist. We then proceed to derive approximate 1-D closure theories through a slender jet asymptotic scaling, combined with appropriate definitions of velocity, pressure and stress unknowns. Our nonaxisymmetric 1-D slender jet models incorporate the physical effects of inertia, viscoelasticity (viscosity, relaxation and retardation), gravity, surface tension, and properties of the ambient fluid, and include shear stresses and time dependence. Previous special 1-D slender jet models correspond to the lowest order equations in the present asymptotic theory by an a posteriori suppression to leading order of some of these effects, and a reduction to axisymmetry. Solutions of the lowest order system of equations in this asymptotic analysis are presented: For the special cases of elliptical inviscid and Newtonian free …
Date: January 1, 1988
Creator: Bechtel, S. E.; Forest, M. G.; Holm, D. D. & Lin, K. J.
Object Type: Article
System: The UNT Digital Library
2.0 K CEBAF Cryogenics (open access)

2.0 K CEBAF Cryogenics

None
Date: October 1, 1988
Creator: Arenius, Dana; Chronis, William; Kashy, David; Keesee, Marie & Rode, Claus
Object Type: Article
System: The UNT Digital Library
2. 5 MeV neutron source for fission cross section measurement (open access)

2. 5 MeV neutron source for fission cross section measurement

A 2.5 MeV neutron source has been established on the beamline of a 100 kV, 0.5 ma ion accelerator. The ion accelerator provides a 100 kV deuteron beam of about 200 ..mu..a into a 3 mm beam spot at the target position. The neutron source is produced by the D(d,n)/sup 3/He reaction with a yield of about 10/sup 7/ n/sec. The time-correlated associated particle method (TCAP) is utilized for the neutron fluence determination and for neutron background elimination. The /sup 3/He associated particles are detected at 90 degrees behind a thin aluminum foil and the corresponding neutrons are emitted at 73.5 degrees with an energy near 2.5 MeV. Also, the protons from the competing D(d,p)T reaction are monitored at 135 degrees for normalization and diagnostic purposes. A fission chamber containing six uranium tetrafluoride deposits has been designed for use in the /sup 235/U(n,f) cross section measurement at 2.5 MeV. The 5 cm diameter deposits range in thickness from 230--300 ..mu..g/cm/sup 2/ and are expected to have good uniformity. A description of the 2.5 MeV neutron source facility is presented along with details of the associated particle detection and neutron beam characteristics. Preparations for the fission cross section measurement are discussed. …
Date: January 1, 1988
Creator: Duvall, K. C.; Wasson, O. A. & Ma, Honchang
Object Type: Article
System: The UNT Digital Library
2-D emittance equation with acceleration and compression (open access)

2-D emittance equation with acceleration and compression

Since both acceleration and compression are required for an Inertial Fusion Driver, the understanding of their effect on the beam quality, emittance, is important. This report attempts to generalize the usual emittance formula for the drifting beam to include these effects. The derivation of the 2-D emittance equation is carried out and a comparison with the particle code results is given. The 2-D emittance at a given axial location is reasonable to consider for a long beam, particularly with velocity tilt; transverse emittance averaged over the entire bunch is not a useful quantity. 6 refs., 2 figs., 1 tab.
Date: October 1, 1988
Creator: Hahn, K. D. & Smith, L.
Object Type: Report
System: The UNT Digital Library
2-D time evolution of T/sub e/ during sawtooth crash based on fast ECE (electron cyclotron emission) measurements on TFTR (open access)

2-D time evolution of T/sub e/ during sawtooth crash based on fast ECE (electron cyclotron emission) measurements on TFTR

Electron cyclotron emission measurements taken at 20 locations in the horizontal midplane during a sawtooth crash have been analysed based on the assumption of fast rigid rotation of the plasma. Due to this fast rotation (approx.100..mu..sec), which remains fairly constant throughout the sawtooth crash, we have been able to make time-to-space reconstructions of half the poloidal plane using points which are separated in time by not more than 40..mu..sec. The existence of a temperature flattening in the precursor phase, which we interpret as an m = 1 temperature island, is clearly demonstrated, and its location and width agree well with local emissivity measurements from soft x-ray tomography viewing the same poloidal plane. The rotating temperature island in the precursor phase, the outward movement of the region of high T/sub c/ during the crash phase, and the shape of T/sub e/ during the crash phase, and the shape of T/sub e/ distribution after the crash during the successor phase have all been documented in a time sequence of color contours. 4 refs., 10 figs.
Date: December 1, 1988
Creator: Kuo-Petravic, G.
Object Type: Report
System: The UNT Digital Library
A 2-MV multi-beam injector for heavy ion fusion (open access)

A 2-MV multi-beam injector for heavy ion fusion

Construction of a sixteen beam (0.5 A per beam) injector for use in scaled heavy ion fusion experiments is underway at LBL. The machine was designed and partially constructed at LANL. The injector is designed to use carbon arc sources which will provide 25 mA/cm/sup 2/ of extractable current density. The plasma from the arcs is confined electrostatically from drifting into the ion gun before firing the extraction pulse. The acceleration column consists of a set of aperture lenses which both transport the beam and attenuate backstreaming electrons. The acceleration column is mounted inside a 28-inch diameter brazed alumina insulating module. The high voltage for the injector is provided by an inductively loaded and graded Marx generator which resides inside a pressure vessel filled with a 65 psig mixture of 30/percent/ SF/sub 6/ and 70/percent/ N/sub 2/. Data is presented showing the performance of single and multiple carbon arc sources. Measurements show that adequate current density is available. Emittance measurements and efforts to improve emittance and reproducibility are shown. Tests with a 5-tray section of the full 18 tray generator are described showing the evolution of the generator design. 5 refs., 3 figs.
Date: June 1, 1988
Creator: Rutkowski, H. L.; Faltens, A.; Vanecek, D.; Pike, C.; Humphries, S., Jr. & Meyer, E. A.
Object Type: Article
System: The UNT Digital Library
3-D magnetic field calculations for wiggglers using MAGNUS-3D (open access)

3-D magnetic field calculations for wiggglers using MAGNUS-3D

The recent but steady trend toward increased magnetic and geometric complexity in the design of wigglers and undulators, of which tapered wigglers, hybrid structures, laced electromagnetic wigglers, magnetic cladding, twisters and magic structures are examples, has caused a need for reliable 3-D computer models and a better understanding of the behavior of magnetic systems in three dimensions. The capabilities of the MAGNUS-3D Group of Programs are ideally suited to solve this class of problems and provide insight into 3-D effects. MAGNUS-3D can solve any problem of Magnetostatics involving permanent magnets, linear or nonlinear ferromagnetic materials and electric conductors of any shape in space. The magnetic properties of permanent magnets are described by the complete nonlinear demagnetization curve as provided by the manufacturer, or, at the user's choice, by a simpler approximation involving the coercive force, the residual induction and the direction of magnetization. The ferromagnetic materials are described by a magnetization table and an accurate interpolation relation. An internal library with properties of common industrial steels is available. The conductors are independent of the mesh and are described in terms of conductor elements from an internal library.
Date: January 1, 1988
Creator: Pissanetzky, S. & Tompkins, P.
Object Type: Article
System: The UNT Digital Library
3-D numerical analysis of a high-gain free-electron laser (open access)

3-D numerical analysis of a high-gain free-electron laser

We present a novel approach to the 3-dimensional high-gain free- electron laser amplifier problem. The method allows us to write the laser field as an integral equation which can be efficiently and accurately evaluated on a small computer. The model is general enough to allow the inclusion of various initial electron beam distributions to study the gain reduction mechanism and its dependence on the physical parameters. 16 refs., 8 figs., 1 tab.
Date: October 19, 1988
Creator: Gallardo, J.C.
Object Type: Report
System: The UNT Digital Library
A 3 TeV on 3 TeV proton-proton dedicated collider for Fermilab (open access)

A 3 TeV on 3 TeV proton-proton dedicated collider for Fermilab

The Fermilab Dedicated Collider proposed in May 1983 is a 2 TeV on 2 TeV p)bar p) collider. The expected luminosity is )approximately) 10/sup 31/ cm/sup (minus/2)sec/sup )minus/1) and the estimated cost is )approximately) $362M (FY-83 dollars). Since 1983 both the superconducting magnet and the particle detector technologies have advanced and the countenance of physics, hence the desired characteristics of new facilities have also altered somewhat. We want to show here that with the new magnet technology used for the SSC one can construct a 3 TeV on 3 TeV pp collider on the Fermilab site. This pp Dedicated Collider )PPDC) will have a luminosity of about 10/sub 33/cm/sup )minus/2)sec)sup)minus)1) and a cost only )approximately) 50)percent) more than that of the p)bar p) Dedicated Collider. 3 figs
Date: March 30, 1988
Creator: Teng, L.C.
Object Type: Report
System: The UNT Digital Library
A 4. pi. tracking magnetic spectrometer for RHIC (open access)

A 4. pi. tracking magnetic spectrometer for RHIC

A tracking magnetic spectrometer based on large Time Projection Chambers (TPC) was previously proposed to measure the momentum of charged particles emerging from the RHIC beam pipe at angles larger than four degrees and to identify the particle type for those beyond fifteen degrees with momenta up to 700 MeV/c, which is a large fraction of the final charged particles emitted by a low cm rapidity quark-gluon plasma. Experimental progress in the successful performance of a TPC developed for AGS E-810 is reported. We have also included typical results of our event generator which contains an interface of an improved HIJET and a plasma bubble model. Typical plasma signals one can expect from this model are presented. 4 refs., 9 figs.
Date: January 1, 1988
Creator: Lindenbaum, S. J.
Object Type: Article
System: The UNT Digital Library
6-Acetyldihydrohomopterin and sepiapterin affect some GTP cyclohydrolase I's and not others (open access)

6-Acetyldihydrohomopterin and sepiapterin affect some GTP cyclohydrolase I's and not others

The first enzyme in pteridine biosynthesis, GTP cyclohydrolase I, is a likely site for regulation of pteridine biosynthesis to occur. GTP cyclohydrolase I responds to hormonal treatment and is found altered in a variety of mice with genetically based neurological and immunological disorders. Genetic loci can greatly modify the activity of GTP cyclohydrolase: Punch mutant in Drosophila hph-1 in mouse and atypical phenylketonuria in human. This report examines the ability of Ahp and sepiapterin to alter the activity of GTP cyclohydrolase I from mouse liver, rat liver and Drosophila head. 20 refs., 2 tabs.
Date: 1988~
Creator: Jacobson, K. Bruce & Manos, Richard E.
Object Type: Article
System: The UNT Digital Library
The 9 Lives of El Gato the Cat: A Fire Safety Comic Book (open access)

The 9 Lives of El Gato the Cat: A Fire Safety Comic Book

Graphic pamphlet about fire safety, including tips for house fires, clothing fires, the dangers of gasoline fumes, electricity burns, and more.
Date: 1988
Creator: United States. Consumer Product Safety Commission.
Object Type: Pamphlet
System: The UNT Digital Library

E-21 (1988)

Photograph of Coyle FD E-21.
Date: 1988
Creator: unknown
Object Type: Photograph
System: The Gateway to Oklahoma History
65 Minutes, January-February, 1988 (open access)

65 Minutes, January-February, 1988

Bimonthly newsletter of Denton Boy Scout Troop 65 containing a list of upcoming events, news and announcements, and other information for members.
Date: January 1988
Creator: Boy Scouts of America. Troop 65 (Denton, Tex.)
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History
65 Minutes, March-April 1988 (open access)

65 Minutes, March-April 1988

Bimonthly newsletter of Denton Boy Scout Troop 65 containing a list of upcoming events, news and announcements, and other information for members.
Date: March 1988
Creator: Boy Scouts of America. Troop 65 (Denton, Tex.)
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History
65 Minutes, May-August 1988 (open access)

65 Minutes, May-August 1988

Bimonthly newsletter of Denton Boy Scout Troop 65 containing a list of upcoming events, news and announcements, and other information for members.
Date: August 1988
Creator: Boy Scouts of America. Troop 65 (Denton, Tex.)
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History
65 Minutes, November-December 1988 (open access)

65 Minutes, November-December 1988

Bimonthly newsletter of Denton Boy Scout Troop 65 containing a list of upcoming events, news and announcements, and other information for members.
Date: November 1988
Creator: Boy Scouts of America. Troop 65 (Denton, Tex.)
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History
65 Minutes, September-October 1988 (open access)

65 Minutes, September-October 1988

Bimonthly newsletter of Denton Boy Scout Troop 65 containing a list of upcoming events, news and announcements, and other information for members.
Date: September 1988
Creator: Boy Scouts of America. Troop 65 (Denton, Tex.)
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History

88-4

Black background with linear patterns and small multi-hued geometric shapes float on the surface.
Date: 1988
Creator: Falsetta, Vincent
Object Type: Artwork
System: The UNT Digital Library
"88" Walk for life (open access)

"88" Walk for life

Brochure to collect pledges for the "88" Walk for Life walk to benefit AIDS care and services in Dallas, to be held on September 17, 1988 at Lee Park in Dallas, Texas.
Date: 1988
Creator: unknown
Object Type: Pamphlet
System: The UNT Digital Library
90-Ton Triple Cylinder Jack Design (open access)

90-Ton Triple Cylinder Jack Design

The three D-Zero cryostats (2 EC and 1 CC) will rest on three carriages which in turn ride on a set of hardened ways in the center beam. A pair of Tychoway rollers will be fitted to each of the four corners of the three carriages to provide the rolling support. In the final design, the two EC cryostats will be able to roll out and away from the CC cryostat in order to provide access to the space between each cryostat for maintenance and repairs. The cryostat will be frequently accessed, about once a month. during a collider run. The heaviest cryostat weighs about 360 tons. The large roller weight in one position for such a long period of time, created a concern about the rollers dimpling the hardened ways or even suffering permanent deformations themselves. There is also the possibility that the vertical position of the cryostat will need to be adjusted to align it with the beam line or that the carriage and cryostat will have to be lifted to remove and service the rollers. A device or system was needed to (1) relieve the weight of the cryostats from the rollers and the hardened ways, and …
Date: September 26, 1988
Creator: Jaques, Al
Object Type: Report
System: The UNT Digital Library

[The 100 Block of West Hubbard]

This picture is an illustration of the south side of the 100 block of West Hubbard Street, looking southeast. The north side (and back view) of Cole's Florist and Hill's Style Shop can be seen at the center of the picture. Lynch Plaza, the darker brick building, is in the left middle background. Oak Avenue (U.S. Highway 281) extends north-south between Cole's House of Flowers and Lynch Plaza. Cole's occupies the site of the former Davidson Hardware, which burned along with the Damron Hotel in 1975. Lynch Plaza, the site of the mineral-water discovery well, was built on the site where the former Oxford Hotel burned in 1983. The parking lot seen in the right foreground of the picture was the site of the Damron Hotel.
Date: September 1988
Creator: unknown
Object Type: Photograph
System: The Portal to Texas History