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3,649 - 3,661 of
3,661
X-324: An upgrade to the NSLS X-Ray Ring using B factory technology
Through much of the last decade, the NSLS has been America`s preeminent source of synchrotron radiation. In the near future, The NSLS will face formidable competition from the third generation light sources, designed to produce high brightness beams from undulators. Because of the lattice design of the NSLS rings and the limited number of straight sections for new undulators it will be impossible to compete with the new rings in brightness at short wavelengths. It is not clear, however, how many experiments really need brightness and how many just need flux. A good strategy could lie in keeping the NSLS the highest flux synchrotron light source in the country and leaving the brightness frontier to the third generation rings. By using the technology developed for the SLAC B factory we can simultaneously raise the X-Ray Ring energy to 3.0 GeV and the current to 2.4 Amp. From these parameters I am calling the proposed upgrade X-324. After the X-324 upgrade, the X-Ray Ring will produce twenty times more synchrotron radiation power than is produced by today`s 250 mA, 2.5 GeV beams. This is a qualitative change from today`s conditions and will place great demands on the RF and vacuum systems. …
Date:
December 2, 1993
Creator:
Blum, E. B.
Object Type:
Report
System:
The UNT Digital Library
X-ray imaging and x-ray source development at Lawrence Livermore National Laboratory
The Laser Program at Lawrence Livermore National Laboratory has a continuing effort to develop both x-ray sources and x-ray sources and x-ray microscopy. This effort includes the ongoing development of: (1) a wide range of x-ray lasers at the Nova Laser Facility, (2) a zone plate lens--multilayer mirror based x-ray microscope (3) three dimensional, high resolution x-ray microscopy (4) short wavelength, normal incidence multilayer x-ray mirrors, (5) compact, high average power lasers for producing x-ray lasers and laser plasma x-ray sources. We have constructed and operated an x-ray laser based transmission x-ray microscope. The advantage offered by the x-ray laser source is the extreme high brightness allows high resolution images to be made on a timescale faster than that for x-ray damage effects to appear. The microscope, consists of: the x-ray laser, a multilayer coated, near normal incidence spherical mirror used as a condenser, a silicon nitride specimen holder, an x-ray zone plate used as an objective lens, and a microchannel plate x-ray detector. The x-ray laser used is the Ni-like Ta x-ray laser operating with a wavelength of 4.48 nm, a pulselength of 200 spec, a divergence of 10 mrad, and an output energy of 10 microjoules.
Date:
December 1, 1993
Creator:
Trebes, J.; Balhorn, R. & Anderson, E.
Object Type:
Article
System:
The UNT Digital Library
X-ray production with sub-picosecond laser pulses
The interaction of intense, sub-picosecond laser pulses with solid targets produces intense picosecond x-ray pulses. With focused laser pulses of several 10 {sup 18} W/cm{sup 2}, He-like and H-like line radiation from targets such as aluminum and silicon has been produced. The energy conversion efficiency from the laser pulse energy to the 1--2 keV line x-rays is nearly one percent. The duration of the line x-ray radiation is of the order of ten picoseconds, although this may be an upper estimate because of the temporal resolution of the x-ray streak camera. The spatial extent of the x-ray source region is only slightly larger than the laser focal spot, or about 10 {mu}m in diameter. With these characteristics, such x-ray sources emit an intensity of nearly 10{sup 14} W/cm{sup 2}. Experiments and modeling which led to the above conclusions will be discussed.
Date:
December 31, 1993
Creator:
Schappert, G. T.; Cobble, J. A.; Fulton, R. D. & Kyrala, G. A.
Object Type:
Article
System:
The UNT Digital Library
Y-12 development organization technical progress report. Part 4, Assembly technology/compatibility and surveillance period ending September 30, 1993
The Super Collider is a high-energy scientific instrument composed of a 53-mile-long ring of proton accelerators designed to collide protons and evaluate the emanating particles. The Oak Ridge Y-12 Plant is under contract to perform work for the Superconducting Super Collider Laboratory (SSCL) and has been asked to develop manufacturing processes for components of the gammas, electrons, muons (GEM) detector. Three welded subassemblies are involved in the fabrication of these conductors. The superconducting cable is enclosed in a stainless steel conduit, which is then enclosed in an aluminum sheath. The ends of the conductor are terminated with a connector assembly joined to the superconductor, the conduit, and the sheath. Initially, the conduit weld was to be a single-pass, autogenous gas-tungsten arc weld. The authors made a great effort to get full penetration without root reinforcement on the inside of the tube. When the authors were unable to meet all of the weld requirements with an autogenous weld, they shifted development efforts to making the weld using an automatic gas-tungsten arc tube welding head with an integral wire feeder. Because reinforcement at the root continued to be a problem, the authors decided to make the weld in two passes. To achieve …
Date:
December 27, 1993
Creator:
Northcutt, W. G. Jr.
Object Type:
Report
System:
The UNT Digital Library
Y-12 development organization technical progress report period ending December 1, 1993. Part 3, Metal processing
Rheocasting is a method to eliminate skull and arc melting from the uranium-6% niobium alloy production stream. A U-6Nb ingot was melted and stirred in the rheocasting furnace.
Date:
December 31, 1993
Creator:
Northcutt, W. G. Jr.
Object Type:
Report
System:
The UNT Digital Library
The Yellow Jacket (Brownwood, Tex.), Vol. 81, No. 10, Ed. 1, Thursday, December 2, 1993
Weekly student newspaper from Howard Payne University in Brownwood, Texas that includes local, state and campus news along with advertising.
Date:
December 2, 1993
Creator:
unknown
Object Type:
Newspaper
System:
The Portal to Texas History
The yield of F-18 from different target designs in the {sup 18}O(p,n){sup 18}F reaction on frozen [{sup 18}O]CO{sub 2}
The shortage of oxygen-18 enriched water has encouraged the authors to explore alternate methods of production of fluorine-18 where the recovery of the oxygen-18 enriched target material is extremely efficient. They have recently presented the results from a cryogenic target using carbon dioxide ice as the target. This is similar in design to a water ice target previously described. The amount of material required and the maximum beam current which can be put on the target are a function of the particular design. The effects of target cone length and number of cooling fins have been explored in order to optimize the target design. Three different targets have been used to test these parameters. The three targets are shown. The first was the prototype target with a single heat sink at the rear of the target. The second is a target with several cooling fins and a short cone length which requires less target material. The third is a target with several cooling fins but a longer target length which allows for more efficient cooling of the material. The results from these studies are summarized. This cryogenic target gives extremely efficient enriched target material recovery (>99%) and simplicity of material …
Date:
December 31, 1993
Creator:
Firouzbakht, M. L.; Schlyer, D. J. & Wolf, A. P.
Object Type:
Report
System:
The UNT Digital Library
Young Children's Construction of Physical Knowledge on Swings in the Outdoor Play Environment
This investigation examined the development of young children's behaviors on swings in the outdoor play environment and their emerging understanding of the physics principles associated with those behaviors. The children's language interactions were also examined in an effort to determine the relationship between language and cognitive development in their construction of physical knowledge. The procedures involved observing the children's behaviors and collecting samples of their spontaneous language interactions during their swinging activities. Informal interviews were also conducted with individual and groups of children. The findings indicate that young children's swinging behaviors develop in eight hierarchical stages. As these behaviors develop, children experiment with the physics principles of balance, gravity, force, resistance, and resonance. Children's swinging behaviors develop in a social context. Many early behaviors are acquired through observing and modeling other children. Language provides the medium for more-experienced peers to assist novice swingers through encouragement and direct instruction. The stage development of swinging behaviors is compared to Cratty's Theory of Perceptual-Motor Development and Harrow's Taxonomy of the Psychomotor Domain. Children's cognitive processing and language interactions are discussed in the context of Piagetian and Vygotskian theories of development. Implications for instruction and suggestions for further research are discussed.
Date:
December 1993
Creator:
Fox, Jill Englebright
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Yucca Mountain Site Characterization Project Technical Data Catalog (Quarterly supplement)
The March 21, 1993, Department of Energy (DOE)/Nuclear Regulatory Commission (NRC) Site-Specific Procedural Agreement for Geologic Repository Site Investigation and Characterization Program requires the DOE to develop and maintain a catalog of data which will be updated and provided to the NRC at least quarterly. This catalog is to include a description of the data; the time (date), place, and method of acquisition; and where it may be examined. The Yucca Mountain Site Characterization Project (YMP) Technical Data Catalog is published and distributed in accordance with the requirements of the Site-Specific Agreement. The YMP Technical Data Catalog is a report based on reference information contained in the YMP Automated Technical Data Tracking System (ATDT). The reference information is provided by Participants for data acquired or developed in support of the YMP. The Technical Data Catalog is updated quarterly and published in the month following the end of each quarter. A complete revision to the Catalog is published at the end of each fiscal year. Supplements to the end-of-year edition are published each quarter. These supplements provide information related to new data items not included in previous quarterly updates and data items affected by changes to previously published reference information. The …
Date:
December 31, 1993
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Z1 Dependence of Ion-Induced Electron Emission
Knowledge of the atomic number (Zt) dependence of ion-induced electron emission yields (Y) can be the basis for a general understanding of ion-atom interaction phenomena and, in particular, for the design of Zrsensitive detectors that could be useful, for example, in the separation of isobars in accelerator mass spectrometry. The Zx dependence of ion-induced electron emission yields has been investigated using heavy ions of identical velocity (v = 2 v0, with v0 as the Bohr velocity) incident in a normal direction on sputter-cleaned carbon foils. Yields measured in this work plotted as a function of the ion's atomic number reveal an oscillatory behavior with pronounced maxima and minima. This nonmonotonic dependence of the yield on Zx will be discussed in the light of existing theories.
Date:
December 1993
Creator:
Arrale, Abdikarim M. (Abdikarim Mohamed)
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Zeeman laser interferometry for detection and chemical analysis
Zeeman interferometry has a number of applications for ultrasensitive detection and chemical analysis, including refractive index detection, micro-thermometry, thermooptic spectroscopy, and light scattering.
Date:
December 1, 1993
Creator:
Johnston, R. G.
Object Type:
Article
System:
The UNT Digital Library
The zinc electrode: Reactions and mechanisms
The zinc electrode in alkaline electrolyte is unusual in that supersaturated zincate solutions can form during discharge and spongy or mossy zinc deposits can form on charge at low overvoltages. This paper reports on in situ x-ray absorption (XAS) results on supersaturated zincate and on mossy deposits.
Date:
December 31, 1993
Creator:
McBreen, J.
Object Type:
Article
System:
The UNT Digital Library
Zone conditioning in a California foothill house
The principal focus of the reported research is the performance of the installed zoned air distribution system in a house located in the foothills northeast of Sacramento California. The 297 m{sup 2} two story house contained a central air conditioner and an air distribution system with four dampered supply duct legs. The air conditioning system included a two speed fan and two speed compressor, with the air handler placed inside a closet and almost all the ducts located inside the building envelope. The uninsulated sheet metal ducts ran inside a space between stories and in interior walls. The performance parameters examined included: (1) duct leakage, (2) duct conduction, (3) zoning performance and (4) equipment efficiency impacts. In conclusion, two major points were made concerning the test house. The first was that substantial energy benefits were obtained by placing the ducts inside the conditioned space. The second was that the energy benefits from zoning the house were not realized, primarily due to thermal stratification and the open floor plan in the house. Secondary impacts lowering zoning performance were the k& of return duct dampers and leakage and conduction losses in the air distribution system. Utility programs or building standards promoting zoning …
Date:
December 1, 1993
Creator:
Jump, D. & Modera, M.
Object Type:
Report
System:
The UNT Digital Library