Showing papers in "Lawrence Berkeley National Laboratory in 1996"

Test Results for a High Field (13T) Nb3Sn Dipole

Abstract: A Nb{sub 3}Sn dipole magnet (D20) has been designed, constructed, and tested at LBNL. Previously, they had reported test results from a hybrid design dipole which contained a similar inner Nb{sub 3}Sn and outer NbTi winding. This paper presents the final assembly characteristics and parameters which will be compared with those of the original magnet design. The actual winding size was determined and a secondary calibration of the assembly pre-load was done by pressure sensitive film. The actual azimuthal and radial D20 pre-loading was accomplished by a very controllable novel stretched wire technique. D20 reached 12.8T(4.4K) and 13.5T(1.8K) the highest dipole magnetic fields obtained to date in the world.

Impact of Information and Communications Technologies on Residential Customer Energy Services

Abstract: LBNL-39015 UC-1322 Impact of Information and Communications Technologies on Residential Customer Energy Services Charles Goldman, Lawrence Berkeley National Laboratory Willett Kempton, Anita Eide and Maithili Iyer, University of Delaware Mindi Farber and Richard Scheer, Energetics, Inc. Energy & Environment Division Lawrence Berkeley National Laboratory University of California Berkeley, California 94720 October 1996 The work described in this study was funded by the Assistant Secretary of Energy Efficiency and Renewable Energy, Office of Utility Technologies, Office of Energy Management Division of the U.S. Department of Energy unde r Contract No. DE-AC03-76SF00098.

Will at least one of the Higgs bosons of the next-to-minimal supersymmetric extension of the standard model be observable at LEP2 or the LHC?

Abstract: We demonstrate that there are regions of parameter space in the next-to-minimal (i.e. two-Higgs-doublet, one-Higgs-singlet superfield) supersymmetric extension of the SM for which none of the Higgs bosons are observable either at LEP2 with $$\sqrt{s}=192 GeV$$ and an integrated luminosity of $L=1000inverse pb$ or at the LHC with $L=600 inverse fb$.

Automation for on-line remote-control in situ electron microscopy

Abstract: We have developed and tested a multimedia system for remote operation of transmission electron microscopes and used it to control the Kratos 1500keV microscope in Berkeley during in-situ experiments.

Forecast of thermal-hydrological conditions and air injection test results of the single heater test at Yucca Mountain

Abstract: The heater in the Single Heater Test (SHT) in alcove 5 of the Exploratory Studies Facility (ESF) was turned on August 26, 1996. A large number of sensors are installed in the various instrumented boreholes to monitor the coupled thermal-hydrological-mechanical-chemical responses of the rock mass to the heat generated in the single heater. In this report the authors present the results of the modeling of both the heating and cooling phases of the Single Heater Test (SHT), with focus on the thermal-hydrological aspect of the coupled processes. Also in this report, the authors present simulations of air injection tests will be performed at different stages of the heating and cooling phase of the SHT.

Target space supersymmetric sigma model techniques

Abstract: We briefly review the covariant formulation of the Green-Schwarz superstring by Berkovits, and describe how a detailed tree-level and one-loop analysis of this model leads, for the first time, to a derivation of the low-energy effective action of the heterotic superstring while keeping target-space supersymmetry manifest. The resulting low-energy theory is old-minimal supergravity coupled to tensor multiplet. The dilaton is part of the compensator multiplet.

Superconducting Magnets for a Muon Collider

Abstract: Superconducting Magnets for a Muon Collider Michael A. Green Ernest Orlando Lawrence Berkeley National Laboratory University of California Berkeley CA. 94720 The existence of a muon collider will be dependent on the use of superconducting magnets. Superconducting magnets for the µ - µ + collider will be found in the following locations: the π - π + capture system, the muon phase rotation system, the muon cooling system, the recirculating acceleration system, the collider ring, and the collider detector system. This report describes superconducting magnets for each of these sections except the detector. In addition to superconducting magnets, superconducting RF cavities will be found in the recirculating accelerator sections and the collider ring. The use of superconducting magnets is dictated by the need for high magnetic fields in order to reduce the length of various machine components. The performance of all of the superconducting magnets will be affected the energy deposited from muon decay products. 1 . INTRODUCTION The proposed muon collider[1-5] consists of the following components: 1) a 10 GeV proton source that generates about 1.5 x 10 1 5 protons per second, 2) a target section that produces and captures pions, 3) a section where the pions decay to muons that are phase rotated to compact bunch, 4) a muon cooling section where the muon emitance is reduced three orders of magnitude, 5) several rings to accelerate muons to 2 TeV, 6) the collider ring, and 7) the detector. Superconducting magnets will be found in all of these sections except for the proton source. This report describes the superconducting solenoids in the pion capture system around the target. A brief description of the solenoids needed in the phase rotation and the muon cooling sections is presented. Dipole and quadrupoles for the recirculating accelerator rings and the collider ring are also described. This report does not include any discussion about superconducting magnets that are part of the detector system around the collider collision point. A muon decays to two neutrinos and electron or positron (depending on the charge state of the original muon). Roughly forty percent of the muon energy ends up in the decay electron or positron. The energy in the electron or positron can be deposited in various parts of the muon collider and its subsystems. The problem of muon decay is at its worst in the collider ring, but it is a problem for superconducting magnets and RF cavities throughout the muon collider subsystems. Muons have a life time that is dictated by its energy. The mean life of a muon at rest is about 2.197 µs. At the collider full energy the of 2 TeV, the muons will have a mean life of 41.6 ms. This means that the repetition rate for the muon collider must be of the order of the muon life time in the collider ring if high colliding ring luminocities are to be maintained. In order to maintain a luminocity of 10 3 5 cm -2 s -1 in a collider ring with a ∫* of 3 mm at the collision point, over 1.2 x 10 1 4 muons per second must be created and stored in a ring with 7 T bending magnets. The collider ring must have two bunches (one of each charge state) of 2x10 1 2 muons per bunch at a repetition rate of 30 Hz in order to have the desired luminocity at the collision point. This work was performed with the support of the Office of High Energy and Nuclear Physics, United States Department of Energy under contract number DE-AC03-76SF00098.

The crystallography of fatigue crack initiation in Incoloy-908 and A-286 steel

Abstract: Fatigue crack initiation in the austenitic Fe-Ni superalloys Incoloy-908 and A-286 is examined using local crystallographic orientation measurements Results are consistent with sharp transgranular initiation and propagation occurring almost exclusively on {l_brace}111{r_brace} planes in Incoloy-908 but on a variety of low index planes in A-286 This difference is attributed to the influence of the semicoherent grain boundary {eta} phase in A-286 Initiation in each alloy occurred both intergranularly and transgranularly and was often associated with blocky surface oxide and carbide inclusions Taylor factor and resolved shear stress and strain crack initiation hypotheses were tested, but despite an inconclusive suggestion of a minimum required {l_brace}111{r_brace} shear stress, none of the hypotheses were found to convincingly describe preferred initiation sites, even within the subsets of transgranular cracks apparently free from the influence of surface inclusions Subsurface inclusions are thought to play a significant role in crack initiation These materials have applications for use in structural conduit for high field superconducting magnets designed for fusion energy use

Regenerative Amplification of Femtosecond Pulses: Design and Construction of a sub-100fs, muon J Laser System

Abstract: LBNL-39658 UC-404 Regenerative Amplification of Femtosecond Pulses: Design and Construction of a sub-! OOfs, I1J Laser System A.B. Schumacher MaterialsSciences Division October 1996 Diplomarbeit .J iD 'D A 'U . CJ o...s. +:>.C r- Z ror+Q Atn-< In fll CJ It) en ro U ro Z w r+ t. ::i (J,j OJ --' a.. to r QJ r:rU1 ru r- r+ -J. 0 c:r <: OJ I.<: U r. OJ Z r u..' m OJ

Design and evaluation of daylighting applications of holographic glazings

Abstract: According to the contractual agreement, BTP would develop a computer model of the POC holographic structures and then simulate the performance of alternative designs using the RADIANCE lighting and rendering computer program [Ward 1990]. The RADIANCE model would then be used to evaluate the daylight performance of alternative designs of holographic glazings in a prototypical office space. The simulation process would be validated against actual photometric measurements of holographic glazing samples developed by POC. The results would be used to evaluate the potential for increased electric lighting savings through increased daylight illuminance levels at distances more than 15 ft--20 ft (4.6 m--6.1 m ) from the window wall.

Progress on PEP-II Magnet Power Conversion System

Abstract: The various power systems for supplying the PEP-II DC magnets rely exclusively on switchmode conversion, utilizing a variety of means depending on the requirements. All of the larger power supplies, ranging from 10 to 200 kW, are powered from DC sources utilizing rectified 480 V AC. Choppers can be used for the series connected strings, but for smaller groups and individual magnets, inverters driving high-frequency transformers with rectifiers comprise the best approach. All of the various systems use a ``building block`` approach of multiple standard-size units connected in series or parallel to most cost-effectively deal with a great range of voltage and current requirements. Utilization of existing infrastructure from PEP-I has been a cost-effective determinant. Equipment is being purchased either off-the-shelf, through performance specification, or by hardware purchase based on design-through-prototype. The corrector magnet power system, utilizing inexpensive, off-the-shelf, four-quadrant switching motor-controllers, has already proven very reliable: 120 of the total of 900 units have been running on the injection system for four months with no failures.

Modeling patterns of hot water use in households

Abstract: LBL-37805 Rev. MODELING PATTERNS OF HOT WATER USE IN HOUSEHOLDS James D. Lutz, Xiaomin Liu, James E. McMahon, Camilla Dunham, Leslie J. Shown, Quandra T. McGrue Energy Analysis Program Energy and Environment Division Ernest Orlando Lawrence Berkeley National Laboratory Berkeley, California 94720 November 1996 This work was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Building Technologies, of the U.S. Department of Energy under Contract No. DE-AC03-76SF00098.

Preliminary engineering analysis for clothes washers

Abstract: The Engineering Analysis provides information on efficiencies, manufacturer costs, and other characteristics of the appliance class being analyzed. For clothes washers, there are two classes: standard and compact. Since data were not available to analyze the compact class, only clothes washers were analyzed in this report. For this analysis, individual design options were combined and ordered in a manner that resulted in the lowest cumulative cost/savings ratio. The cost/savings ratio is the increase in manufacturer cost for a design option divided by the reduction in operating costs due to fuel and water savings.

Nb3Sn Artificial Pinning Microstructures

Abstract: Extension of the APC approach to Nb{sub 3}Sn requires that a second phae be incorporated into the Nb{sub 3}Sn layer. The second phase would increase pinning strength by either reducing the grain size or by the second phase pinning the flux itwelf. The following criteria for elements to be candidates for the APC approach are: (1) they must form intermetallic compounds with Cu or Sn and (2) they must have negligible solubility in Cu and Nb or they must be strong oxide formers. many of the rare earth elements satisfy these criteria. To circumvent the large strains required to produce wires with a fine distribution of the second phase, film deposition techniques have been used. Critical current densities for Nb films doped with Ti and Y are about 4,000 A/mm{sup 2} at 6T and 4.2 K.

Design and Construction of the PEP-II Low Energy Ring

Abstract: We describe the design and construction status of theLow-Energy Ring (LER) of the PEP-II project, a collaboration of SLAC,LBNL, and LLNL. In the past year we have optimized LER parameters andstarted component fabrication. By reusing the original wigglers, we wereable to simplify the design of the distributed wiggler photon dump, whichmust dissipate 260 kW of power. The number of RF stations (eachcomprising a klystron powering two 476-MHz cavities) was reduced from 4to 3. We have begun fabrication of the arc vacuum system based on anextruded Al antechamber configuration with discrete photon stops andTSPs. The design of the straight section vacuum components, to befabricated from stainless steel pipe, is also completed. Quadrupoles anddipoles are provided under a collaborative agreement with IHEP (Beijing);correctors and skew quadrupoles are built domestically and sextupoles arerefurbished from existing PEP magnets. LER commissioning will begin earlyin 1998.

Quantum Monte Carlo for vibrating molecules

Abstract: Quantum Monte Carlo (QMC) has successfully computed the total electronic energies of atoms and molecules. The main goal of this work is to use correlation function quantum Monte Carlo (CFQMC) to compute the vibrational state energies of molecules given a potential energy surface (PES). In CFQMC, an ensemble of random walkers simulate the diffusion and branching processes of the imaginary-time time dependent Schroedinger equation in order to evaluate the matrix elements. The program QMCVIB was written to perform multi-state VMC and CFQMC calculations and employed for several calculations of the H{sub 2}O and C{sub 3} vibrational states, using 7 PES`s, 3 trial wavefunction forms, two methods of non-linear basis function parameter optimization, and on both serial and parallel computers. In order to construct accurate trial wavefunctions different wavefunctions forms were required for H{sub 2}O and C{sub 3}. In order to construct accurate trial wavefunctions for C{sub 3}, the non-linear parameters were optimized with respect to the sum of the energies of several low-lying vibrational states. In order to stabilize the statistical error estimates for C{sub 3} the Monte Carlo data was collected into blocks. Accurate vibrational state energies were computed using both serial and parallel QMCVIB programs. Comparison of vibrationalmore » state energies computed from the three C{sub 3} PES`s suggested that a non-linear equilibrium geometry PES is the most accurate and that discrete potential representations may be used to conveniently determine vibrational state energies.« less