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The U5. 0 undulator design for the advanced light source at LBL
The U5.0 undulator, currently under design, is the first in a series of insertion devices planned for the Advanced Light Source at LBL. U5.0 parameters include a 5 cm period, 5 m length with a 0.837 T maximum field at a 14 mm gap. A hybrid configuration utilizing Nd-Fe-B permanent magnet material and Vanadium Permendur poles is used for the magnetic structure. Construction is modular with many pole assemblies attached to a pole mount, which in turn is fastened onto one of the backing beams. Vertical field integral correction at the ends is with permanent magnet rotators. The supports structure features a 4-post configuration, a rigid base with 3 kinematic floor supports and 2 rigid 5 m long backing beams that fit within the 2.4 m high accelerator enclosure. The drive system is computer controlled utilizing a stepper motor and shaft encode coupled to a roller-screw/nut and chain drive train. Vacuum chamber design is a rigid configuration with a 10 mm vertical by 218 mm horizontal aperture of 5.5 m length. Chamber fabrication features a two-piece welded chamber of 5083 H321 aluminum. Pumping is with ion and titanium sublimation pumps. 5 figs., 1 tab.
Date:
August 1, 1989
Creator:
Hoyer, E.; Chin, J.; Halbach, K.; Hassenzahl, W.; Humphries, D.; Kincaid, B. et al.
Object Type:
Article
System:
The UNT Digital Library
The collaborative program of research in engineering sciences
Research programs in the following areas are briefly described: High-Temperature Gas-Particle Reactions; Mathematical Modelling of Plasma Systems; Metal Transfer in Gas Metal-Arc Welding; Multivariable Control of Gas Metal-Arc Welding; Synthesis of Heat and Work Integration Systems for Chemical Process Plants; Parity Simulation of Dynamic Processes; Fundamentals of Elastic-Plastic Fracture: Three-Dimensional and Mechanistic Modelling; and Comminution of Energy Materials. Publications from each program are listed.
Date:
August 1, 1989
Creator:
White, D.C.
Object Type:
Report
System:
The UNT Digital Library
Production and decay of heavy top quarks
Experimental evidence indicates that the top quark exists and has a mass between 50 and 200 GeV/c{sup 2}. The decays of a top quark with a mass in this range are studied with emphasis placed on the mass region near the threshold for production of real W bosons. Topics discussed are: (1) possible enhancement of strange quark production when M{sub W} + m{sub s} < m{sub t} < M{sub W} + m{sub b}; (2) exclusive decays of T mesons to B and B{asterisk} mesons using the non-relativistic quark model; (3) polarization of intermediate W's in top quark decay as a source of information on the top quark mass. The production of heavy top quarks in an e{sup +}e{sup {minus}} collider with a center-of-mass energy of 2 TeV is studied. The effective-boson approximation for photons, Z{sup 0}'s and W's is reviewed and an analogous approximation for interfaces between photons and Z{sup 0}'s is developed. The cross sections for top quark pair production from photon-photon, photon-Z{sup 0}, Z{sup 0}Z{sup 0}, and W{sup +}W{sup {minus}} fusion are calculated using the effective-boson approximation. Production of top quarks along with anti-bottom quarks via {gamma}W{sup +} and Z{sup 0}W{sup +} fusion is studied. An exact calculation …
Date:
August 1, 1989
Creator:
Kauffman, R.P.
Object Type:
Report
System:
The UNT Digital Library
[Letter from Jack Davis and Bill McCarter to Nancy Timmons, August 23, 1989]
Photocopy of a letter from Jack Davis and Bill McCarter, co-directors of North Texas Institute for Educators on the Visual Arts, to Dr. Nancy Timmons, Fort Worth ISD. In regards to confirm an appointment on August 31 to discuss the North Texas Regional Institute for Educators on the Visual Arts. McCarter and Davis write a little bit about what the program intends to do, such as prepare teachers and school administrators to implement discipline-based art education on a district wide basis, and wishing to discuss in further detail to Timmons on what their program can do for the FWISD schools.
Date:
August 23, 1989
Creator:
Davis, Donald Jack & McCarter, William
Object Type:
Letter
System:
The UNT Digital Library
Multilayer optical elements for generation and analysis of circularly polarized x-rays
Calculations of the relative phase changes of {sigma} and {pi} electric field components on Bragg reflection from and transmission through multilayers are presented. Large relative phase changes can be calculated in certain cases, which may lead to utility of multilayers as quarter-wave plates for generation and analysis of circularly polarized soft x-radiation. Similar behavior may be expected for perfect crystals in the hard x-ray range. 24 refs., 4 figs.
Date:
August 1, 1989
Creator:
Kortright, J.B. & Underwood, J.H.
Object Type:
Article
System:
The UNT Digital Library
Raman microprobe investigation of molecular structure and organization in the native state of woody tissue
Although the primary emphasis of our program has remained with the application of Raman spectroscopy to the study of native tissue, the scope of the work has been expanded to include a number of complementary approaches. These have included Solid State 13C NMR, autoradiography of radiolabeled woody tissue sections, and the generation of biomimetic tertiary aggregates which simulate states of aggregation characteristic of cell walls. Our Raman spectroscopic studies have resulted in progress in the areas of interpretation of the spectral features, and confirmation of the variability of the patterns of orientation of lignin reported earlier. We have assembled and made operational our new microprobe and spectrometer systems acquired under the DOE-URIP program. We have also demonstrated that, operating with gated detection and pulsed laser excitation, we can discriminate against the laser-excited fluorescence characteristic of most woody tissue. Our studies of celluloses, which combine Raman spectroscopy and 13C NMR have shown that all native celluloses are composites of two forms which have the same secondary structure but different tertiary structures.
Date:
August 1, 1989
Creator:
Atalla, R.H.
Object Type:
Report
System:
The UNT Digital Library
An assessment of the effects of radiation on permanent magnet material in the ALS (Advanced Light Source) insertion devices
Electrons that are lost from the beam during normal operation of a synchrotron radiation source and during a beam dump at the end of a run produce both ionizing radiation and neutrons. This radiation has the potential for damaging sensitive materials, in particular those that need to be very close to the beam. The wigglers and undulators for the Advanced Light Source (ALS) at LBL will use magnetic materials such as the very high performance neodymium-iron-boron, which will be as close as 1 cm away from the electron beam during operation. This material, which is preferred because of its high remanence, is known to be more sensitive to radiation than some other magnetic materials. Simple energy loss estimates and the EGS4 code were used to estimate the radiation levels in the ALS insertion devices in the regions of the magnetic materials. The radiation levels were estimated for both aluminum and stainless steel vacuum chambers to determine if one would provide significantly better shielding. We conclude that Nd-Fe-B can be used in the ALS insertion devices and that there is little difference in the radiation levels for aluminum and stainless vacuum vessels. 8 refs., 7 figs., 1 tab.
Date:
August 1, 1989
Creator:
Hassenzahl, W. V.; Jenkins, T. M.; Namito, Y.; Nelson, W. R. & Swanson, W. P.
Object Type:
Article
System:
The UNT Digital Library
Cycle-life improvement of Zn/NiOOH cells by the addition of Ca(OH) sub 2 to the zinc electrode
The addition of Ca(OH){sub 2} to the zinc electrode of Zn/NiOOH cells was investigated in order to determine its effect on reducing the rate of Zinc redistribution. Cells containing 0, 10, 25, and 40 mol% Ca(OH){sub 2} in the zinc electrode were constructed and tested. Ca(OH){sub 2} was found to form a calcium zincate complex with the zincate-supersaturated KOH solution created during the discharge half-cycle. As Ca(OH){sub 2} is insoluble in the electrolyte, the formation of this complex (containing two Zn atoms to one Ca) significantly reduces the Zinc redistribution rate. Electrodes with only 10% Ca(OH){sub 2} were found to contain insufficient Ca(OH){sub 2} to complex with enough Zinc to make a dramatic improvement on cycle life. The 25%-Ca(OH){sub 2} electrodes, however, were found to retain their capacity beyond 150 deep discharge cycles, with indication that further Zinc redistribution would occur very slowly. The Zinc utilization of the Ca-containing electrodes showed dramatic improvement over the Ca-free zinc electrodes. 23 refs., 49 figs., 7 tabs.
Date:
August 1, 1989
Creator:
Jain, R.; McLarnon, F. R. & Cairns, E. J.
Object Type:
Report
System:
The UNT Digital Library
Cosmic ray half life of sup 54 Mn
A search for the {beta}{sup +} decay of {sup 54}Mn has established an upper limit of 4.4 {times} 10{sup {minus}8} for this branching ratio, and a lower limit of 13.3 for the log ft value for this second forbidden unique transition. Assuming that the {beta}{sup {minus}} decay branch has the same log ft value, then its partial half life must be greater than 4 {times} 10{sup 4} years. Experiments to directly measure the {beta}{sup {minus}} decay rate of {sup 54}Mn are now in progress. 6 refs., 2 figs.
Date:
August 1, 1989
Creator:
Norman, E.B.; Sur, B.; Vogel, K.R.; Lesko, K.T.; Larimer, R.M. & Browne, E.
Object Type:
Article
System:
The UNT Digital Library
The digital data acquisition chain and the cosmic ray trigger system for the SLD Warm Iron Calorimeter
The entire data-acquisition chain, from the custom-made front-end electronics to the Fastbus readout and data-reduction module, for the digital readout of the SLD limited streamer tube Warm Iron Calorimeter and Muon Identifier is described. Also described is a Fastbus Cosmic Logic Unit being developed to achieve the capability of reading cosmic ray events, also during the inter-crossing time, for apparatus monitoring and calibration purposes. 9 refs., 9 figs.
Date:
August 1, 1989
Creator:
Benvenuti, A.; Piemontese, L.; Calcaterra, A.; De Sangro, R.; De Simone, P.; Burrows, P. N. et al.
Object Type:
Article
System:
The UNT Digital Library
Augmented Fish Health Monitoring, 1988 Annual Report.
Augmented Fish Health Monitoring Contract AI79-87BP35585 was implemented on July 20, 1987. Second year activities focused on full implementation of disease surveillance activities and histopathological support services to participating state agencies. Persistent and sometimes severe disease losses were caused by infectious hematopoietic necrosis (IHN) in summer steelhead trout in Idaho and in spring chinook salmon at hatcheries on the lower Columbia River. Diagnostic capability was enhanced by the installation, for field use, of enzyme-linked immunosorbent assay (ELISA) technology at the Dworshak Fish Health Center for the detection and assay of bacterial kidney disease and by a dot-blot'' training session for virus identification at the Lower Columbia Fish Health Center. Complete diagnostic and inspection services were provided to 13 Columbia River basin National Fish hatcheries. Case history data was fully documented in a computerized data base for storage and analysis. This report briefly describes work being done to meet contract requirements for fish disease surveillance at Service facilities in the Columbia River basin. It also summarizes the health status of fish reared at those hatcheries and provides a summary of case history data for calendar year 1988. 2 refs., 4 tabs.
Date:
August 15, 1989
Creator:
Warren, James W.
Object Type:
Report
System:
The UNT Digital Library
Cosmic ray events in Soudan 2
The Soudan 2 detector is located at a depth of 2090 meters-water equivalent (mwe). About 2 million muon events have been recorded. Here we report on our plans to analyze them for comparison with expectations from atmospheric cosmic ray models. Plans and capabilities to analyze multiple muons and monopoles are also discussed. 3 refs., 5 figs.
Date:
August 23, 1989
Creator:
Allison, W. W. M.; Alner, G. J.; Ambats, I.; Ayres, D.; Balka, L.; Barr, G. D. et al.
Object Type:
Article
System:
The UNT Digital Library
The shell model approach: Key to hadron structure
A shell model approach leads to a simple constituent quark model for hadron structure in which mesons and baryons consist only of constituent quarks. Hadron masses are the sums of the constituent quark effective masses and a hyperfine interaction inversely proportional to the product of these same masses. Hadron masses and magnetic moments are related by the assumption that the same effective mass parameter appears in the additive mass term, the hyperfine interaction, and the quark magnetic moment, both in mesons and baryons. The analysis pinpoints the physical assumptions needed for each relation and gives two new mass relations. Application to weak decays and recent polarized EMC data confirms conclusions previously obtained that the current quark contribution to the spin structure of the proton vanishes, but without need for the questionable assumption of SU(3) symmetry relating hyperon decays and proton structure. SU(3) symmetry breaking is clarified. 24 refs.
Date:
August 14, 1989
Creator:
Lipkin, H.J. (Weizmann Inst. of Science, Rehovoth (Israel). Dept. of Nuclear Physics)
Object Type:
Article
System:
The UNT Digital Library
Studies of. mu. prime s underground with the Soudan 2 Tracker
During the period July 1987 through March 1988, a section of the Soudan 2 active shield known as the Tracker' recorded {approximately}250,000 muon tracks. The detector is located in the Tower-Soudan State Park in Soudan, Minnesota USA at a depth of 2090 meters-water equivalent. We have analysed the data collected and searched for time-dependent astronomical sources. Distributions in azimuthal and zenith angles as well as declination and right ascension are shown. 1 ref., 7 figs., 1 tab.
Date:
August 23, 1989
Creator:
Kochocki, J.; Benjamin, D.; Ewen, B.; Kafka, T.; Mann, A.; McMaster, L. et al.
Object Type:
Article
System:
The UNT Digital Library
Grazing-incidence Cerenkov x-ray generation
X-ray Cerenkov radiation can be generated by electrons incident on thin foils. For grazing incidence the Cerenkov radiation intensity can be more than a decade greater than for perpendicular incidence. Experimental results are discussed in terms of a simple formalism. 17 refs., 3 figs.
Date:
August 1, 1989
Creator:
Moran, Michael J.; Chang, Britton; Schneider, Marilyn B. & Maruyama, Xavier K.
Object Type:
Article
System:
The UNT Digital Library
A database of fragmentation cross section measurements applicable to cosmic ray propagation calculations
A database of single particle inclusive fragment production cross section measurements has been established and is accessible over common computer networks. These measurements have been obtained from both published literature and direct communication with experimenters and include cross sections for nuclear beams on H, He, and heavier targets, and for H and He beams on nuclear targets, for energies >30 MeV/nucleon. These cross sections are directly applicable to calculations involving cosmic ray nuclear interactions with matter. The data base includes projectile, target, and fragment specifications, beam energy, cross section with uncertainty, literature reference, and comment code. It is continuously updated to assure accuracy and completeness. Also available are widely used semi-empirical formulations for calculating production cross sections and excitation functions. In this paper we discuss the database in detail and describe how it can be accessed. We compare the measurements with semi-empirical calculations and point out areas where improved calculations and further cross section measurements are required. 5 refs., 2 figs.
Date:
August 1, 1989
Creator:
Crawford, H. J.; Engelage, J.; Jones, F. C.; Guzik, T. G.; Mitchell, J. W.; Wefel, J. P. et al.
Object Type:
Article
System:
The UNT Digital Library
Challenges for utilization of the new synchrotron facilities
The emergence of third generation synchrotron radiation facilities provides new scientific opportunities and challenges. Optimized for small phase space electron beams, long periodic magnet structures, and dedicated scientific user access -- these new machines promise significant increases in spectral brightness, as well as enhanced spatial and temporal coherence properties, which translates to new opportunities for combining high spatial and spectral resolution. The challenges to the machine builders are well known: designing and maintaining the small phase space beams, constructing long magnet structures with minimal errors, stabilizing the beam to long and short term fluctuations, and multiple undulator tuning, to name a few. The challenges in beamline optics, spectroscopic and focusing systems are also quite clear. The issue of optical stability quickly comes to the forefront as we attempt to focus and image to ever finer spatial scales, with minimal loss of photon flux. Surface figure and polish are of greater importance, as is minimization of aberrations, as we strive to maintain these small phase space photon beams. The higher intensities and power loading mandate cooled, or cleverly controlled optics, to avoid thermal distortion. Spectroscopic efficiency, with minimal wavefront distortion to the near diffraction limited radiation, becomes more important, as do …
Date:
August 1, 1989
Creator:
Attwood, D.
Object Type:
Article
System:
The UNT Digital Library
Exotic signatures from supersymmetry
Minor changes to the standard supersymmetric model, such as soft flavor violation and R parity violation, cause large changes in the signatures. The origin of these changes and the resulting signatures are discussed. 15 refs., 7 figs., 2 tabs.
Date:
August 1, 1989
Creator:
Hall, L. J.
Object Type:
Article
System:
The UNT Digital Library
Relief valve sizing for the sup 3 He recirculation system of the MP-9 polarized target
This report contains pressure safety analyses for the relief valving of the {sup 3}He pump system, as distinct from the dilution refrigerator (DR). However, in a few instances it has been convenient to include here some aspects of the interaction between the DR and the gas loop proper. The more localized safety aspects of certain elements of the DR, such as the vacuum jacket and window, the Still, and the Phase Separator, will be addressed in a separate analysis.
Date:
August 21, 1989
Creator:
Hill, D.
Object Type:
Report
System:
The UNT Digital Library
Supernovae, compact stars and nuclear physics
We briefly review the current understanding of supernova. We investigate the implications of rapid rotation corresponding to the frequency of the new pulsar reported in the supernovae remnant SN1987A. It places very stringent conditions on the equation of state if the star is assumed to be bound by gravity alone. We find that the central energy density of the star must be greater than 12 times that of nuclear density to be stable against the most optimistic estimate of general relativistic instabilities. This is too high for the matter to plausibly consist of individual hadrons. We conclude that the newly discovered pulsar, if its half-millisecond signals are attributable to rotation, cannot be a neutron star. We show that it can be a strange quark star, and that the entire family of strange stars can sustain high rotation under appropriate conditions. We discuss the conversion of a neutron star to strange star, the possible existence of a crust of heavy ions held in suspension by centrifugal and electric forces, the cooling and other features. 39 refs., 8 figs., 2 tabs.
Date:
August 25, 1989
Creator:
Glendenning, N.K.
Object Type:
Article
System:
The UNT Digital Library
Electrical Resistivity of Strongly Coupled Plasmas in Intense Fields
It is now possible to measure the electrical resistivity, or alternatively the electron collision frequency, in strongly coupled plasmas through the use of very fast laser pulses. In such experiments, the effect of the intense laser field needs to be included in the calculation of material transport coefficients. We derive a form for the electrical resistivity which includes the effects of strong correlations, as well as an external electric field. Our results are compared with other theories and a recent set of experiments. 17 refs., 1 fig.
Date:
August 1, 1989
Creator:
Cauble, R.; Rogers, F.J. (Lawrence Livermore National Lab., CA (USA)) & Rozmus, Wojtek (Alberta Univ., Edmonton, AB (Canada). Theoretical Physics Inst.)
Object Type:
Article
System:
The UNT Digital Library
Contained Events in Soudan 2
A search for contained events in the Soudan 2 nucleon decay detector has been made for the initial exposure of the first quarter of the 1.1 kiloton detector. This corresponds to an exposure of 0.083 kiloton years in the fiducial volume. We observe 5 {nu}{sub mu} candidate events and 5 {nu}{sub e} candidate events. Results of Monte Carlo simulations of neutrino events and proton decay events in Soudan 2 are compared. 6 refs., 3 figs.
Date:
August 23, 1989
Creator:
Allison, W. W. M.; Alner, G. J.; Ambats, I.; Balka, L.; Barr, G. D.; Benjamin, D. et al.
Object Type:
Article
System:
The UNT Digital Library
Calculation of magnetic error fields in hybrid insertion devices
The Advanced Light Source (ALS) at the Lawrence Berkeley Laboratory requires insertion devices with fields sufficiently accurate to take advantage of the small emittance of the ALS electron beam. To maintain the spectral performance of the synchrotron radiation and to limit steering effects on the electron beam these errors must be smaller than 0.25%. This paper develops a procedure for calculating the steering error due to misalignment of the easy axis of the permanent magnet material. The procedure is based on a three dimensional theory of the design of hybrid insertion devices developed by one of us. The acceptable tolerance for easy axis misalignment is found for a 5 cm period undulator proposed for the ALS. 11 refs., 5 figs.
Date:
August 1, 1989
Creator:
Savoy, R.; Halbach, K.; Hassenzahl, W.; Hoyer, E.; Humphries, D. & Kincaid, B.
Object Type:
Article
System:
The UNT Digital Library
Weighted fit of parametric functions to distributions: The new interface of HOBOOK with MINUIT
The fitting routines of the HBOOK package allow weighted fit of parametric functions to the contents of a one, two or N-dimensional distribution, and analysis of the function in the neighborhood of its minimum, through an interface with the MINUIT package. These routines have been rewritten so as to interface the new version of MINUIT and to allow for smooth transitions to future versions of both packages. We discuss the interface and its capabilities: it is more stable than the previous version and presents a more accurate error analysis. The fitting algorithm is based on the Fletcher method, known for its reliability. Exponential, Gaussian and polynomial fitting are provided, as well as arbitrary user-defined fitting, to one, two and N-dimensional distributions. For the latter, the user is required to provide a smooth parametric function and is given the ability to guide the algorithm in finding the desired minimum. Examples are given. 6 refs., 1 fig.
Date:
August 1, 1989
Creator:
Lessner, E.S.
Object Type:
Article
System:
The UNT Digital Library