The U5. 0 Undulator for the ALS (open access)

The U5. 0 Undulator for the ALS

the U5.0 Undulator, and 89 period, 5 cm period length, 4.6 m long insertion device has been designed, is being fabricated and is scheduled for completion in early 1992. This undulator will be the first high brightness source, in the 50 to 1500 eV range, for the Advanced Light Source (ALS) at the Lawrence Berkeley Laboratory. A hybrid magnetic configuration using Nd-Fe-B permanent magnet material and vanadium permendur poles has been selected to achieve the field quality needed to meet performance requirements. The magnetic structure is modular with each half consisting of 5 assembly sections, which provide the periodic structure, and end structures, for entrance and exit correction, mounted on a steel backing beam. Each assembly section consists of 35 half-period pole assemblies bolted to a mount. The required 0.837 Tesla effective peak field at a 1.4 cm gap has been verified with model measurements. Vertical field integral correction is accomplished with the end structures, each having an arrangement of permanent magnet rotors which will be adjusted to minimize electron beam missteering over the undulator operating field range. To reduce the effect of environmental fields, the steel backing beams are connected through parallel, low-reluctance, Ni-Fe hinges. The magnetic structure is …
Date: July 15, 1991
Creator: Hoyer, E.; Chin, J.; Halbach, K.; Hassenzahl, W.V.; Humphries, D.; Kincaid, B. et al.
System: The UNT Digital Library
Space propulsion by fusion in a magnetic dipole (open access)

Space propulsion by fusion in a magnetic dipole

The unique advantages of fusion rocket propulsion systems for distant missions are explored using the magnetic dipole configurations as an example. The dipole is found to have features well suited to space applications. Parameters are presented for a system producing a specific power of kW/kg, capable of interplanetary flights to Mars in 90 days and to Jupiter in a year, and of extra-solar-system flights to 1000 astronomical units (the Tau mission) in 20 years. This is about 10 times better specific power performance than nuclear electric fission systems. Possibilities to further increase the specific power toward 10 kW/kg are discussed, as is an approach to implementing the concept through proof-testing on the moon. 20 refs., 14 figs., 2 tabs.
Date: July 15, 1991
Creator: Teller, E.; Glass, A.J.; Fowler, T.K. (Lawrence Livermore National Lab., CA (United States)); Hasegawa, A. (AT and T Bell Labs., Murray Hill, NJ (United States)) & Santarius, J.F. (Wisconsin Univ., Madison, WI (United States). Fusion Technology Inst.)
System: The UNT Digital Library
Varied line-space gratings and applications (open access)

Varied line-space gratings and applications

This paper presents a straightforward analytical and numerical method for the design of a specific type of varied line-space grating system. The mathematical development will assume plane or nearly-plane spherical gratings which are illuminated by convergent light, which covers many interesting cases for synchrotron radiation. The gratings discussed will have straight grooves whose spacing varies across the principal plane of the grating. Focal relationships and formulae for the optical grating-pole-to-exist-slit distance and grating radius previously presented by other authors will be derived with a symbolic algebra system. It is intended to provide the optical designer with the tools necessary to design such a system properly. Finally, some possible advantages and disadvantages for application to synchrotron to synchrotron radiation beamlines will be discussed.
Date: July 15, 1991
Creator: McKinney, W.R.
System: The UNT Digital Library
ASSESS (Analytic System and Software for Evaluating Safeguards and Security) update: Current status and future developments (open access)

ASSESS (Analytic System and Software for Evaluating Safeguards and Security) update: Current status and future developments

The Analytic System and Software for Evaluating Safeguards and Security (ASSESS) has been released for use by DOE field offices and their contractors. In October, 1989, we offered a prototype workshop to selected representatives of the DOE community. Based on the prototype results, we held the first training workshop at the Central Training Academy in January, 1990. Four additional workshops are scheduled for FY 1990. ASSESS is a state-of-the-art analytical tool for management to conduct integrated evaluation of safeguards systems at facilities handling facilities. Currently, ASSESS focuses on the threat of theft/diversion of special nuclear material by insiders, outsiders, and a special form of insider/outsider collusion. ASSESS also includes a neutralization module. Development of the tool is continuing. Plans are underway to expand the capabilities of ASSESS to evaluate against violent insiders, to validate the databases, to expand the neutralization module, and to assist in demonstrating compliance with DOE Material Control and Accountability (MC A) Order 5633.3. These new capabilities include the ability to: compute a weighted average for performance capability against a spectrum of insider adversaries; conduct defense-in-depth analyses; and analyze against protracted theft scenarios. As they become available, these capabilities will be incorporated in our training program. ASSESS …
Date: July 15, 1990
Creator: Al-Ayat, R.A. (Lawrence Livermore National Lab., CA (USA)); Cousins, T.D. (USDOE, Washington, DC (USA)) & Hoover, E.R. (Sandia National Labs., Albuquerque, NM (USA))
System: The UNT Digital Library
Fast pulsars, strange stars: An opportunity in radio astronomy (open access)

Fast pulsars, strange stars: An opportunity in radio astronomy

The world's data on radio pulsars is not expected to represent the underlying pulsar population because of a search bias against detection of short periods, especially below 1 ms. Yet pulsars in increasing numbers with periods right down to this limit have been discovered suggesting that there may be even shorter ones. If pulsars with periods below 1/2 ms were found, the conclusion that the confined hadronic phase of nucleons and nuclei is only metastable would be almost inescapable. The plausible ground state in that event is the deconfined phase of (3-flavor) strange-quark-matter. From the QCD energy scale this is as likely a ground state as the confined phase. We show that strange matter as the ground state is not ruled out by any known fact, and most especially not by the fact that the universe is in the confined phase. 136 refs.
Date: July 15, 1990
Creator: Glendenning, N.K.
System: The UNT Digital Library
An intensity interferometer for soft x-rays (open access)

An intensity interferometer for soft x-rays

We designed and built an intensity interferometer to characterize the spatial coherence of a soft x-ray undulator beam. The beam source size and shape can be determined from the measured coherence function. The instrument is 400 mm long and is mounted on a standard 204-mm diameter flange. This compact design is readily adaptable to other beamlines with sources of sufficient spectral brightness. Details of the interferometer design and performance are presented. We anticipate that when this technique is mature, it will provide a useful diagnostic for high brightness x-ray beams.
Date: July 15, 1994
Creator: Yang, L.; McNulty, I. & Gluskin, E.
System: The UNT Digital Library
Performance of a high resolution, high flux density SGM undulator beamline at the ALS (open access)

Performance of a high resolution, high flux density SGM undulator beamline at the ALS

The performance of ALS beamline 7.0 is described. This is an integrated system for delivering radiation from a 5cm period undulator to spectroscopy and microscopy experiments across the range of photon energies from 60eV to 1200eV. The beamline is engineered to deliver the highest possible flux, with negligible deformation of the optic surfaces due to heating. Two experiment stations are served with rapid interchangeability. We report on the measured operational parameters, the resolution and flux delivered, and the refocus of the light into a small spot at the experiment.
Date: July 15, 1994
Creator: Warwick, T.; Heimann, P.; Mossessian, D.; McKinney, W. & Padmore, H.
System: The UNT Digital Library
Experimental characterization of ALS undulator radiation (open access)

Experimental characterization of ALS undulator radiation

The radiation from the 5 cm period undulator at the Advanced Light Source (ALS) has been characterized using a transmission grating spectrometer. Spectral and angular distributions of radiation were measured for deflection parameter K values between 0.45 and 2.12 at low storage ring current (0.1--0.5 mA). From the calibration of the spectrometer, the absolute flux density of the undulator harmonics has been determined together with the spectral linewidth. The electron the beam emittance was determined by analyzing the angular distribution of the red-shifted fundamental. Comparison has been made with radiation calculations based upon the measured magnetic field data of the undulator. Including field errors, electron beam emittance and energy spread, good agreement is found between theoretically and experimentally determined harmonic widths and peak brightness.
Date: July 15, 1994
Creator: Heimann, P.; Mossessian, D.; Warwick, A.; Gullikson, E.; Wang, C.; Marks, S. et al.
System: The UNT Digital Library
Using a straightness reference in obtaining more accurate surface profiles from a Long Trace Profiler (open access)

Using a straightness reference in obtaining more accurate surface profiles from a Long Trace Profiler

The Long Trace Profiler has found significant applications in measuring the surfaces of synchrotron optics. However, requirements of small slope errors at all spatial wavelengths of the synchrotron optics mandate more accurate slope measurements. A straightness reference for the Long Trace Profiler greatly increases the accuracy of the instrument. Methods of using the straightness reference by interpreting the sequential interference patterns are discussed and results of measurements are presented.
Date: July 15, 1991
Creator: Irick, S. C.; McKinney, W. R.; Lunt, D. L. J. & Takacs, P. Z.
System: The UNT Digital Library
Performance of photon position monitors and stability of undulator beams at the Advanced Light Source (open access)

Performance of photon position monitors and stability of undulator beams at the Advanced Light Source

Position monitors are implemented in three undulator beamlines at the ALS. Their performance has been studied carefully on one of these lines and is reviewed. The monitors work as expected and show the ALS to be an exceptionally stable source of synchrotron radiation.
Date: July 15, 1994
Creator: Warwick, T.; Andresen, N.; Portmann, G. & Jackson, A.
System: The UNT Digital Library
Microstructurally based mechanisms for modeling shrinkage of cement paste at multiple levels (open access)

Microstructurally based mechanisms for modeling shrinkage of cement paste at multiple levels

Shrinkage of cement paste is controlled by a number of mechanisms that operate in various parts of the microstructure and at various length scales. A model for creep and shrinkage can be developed by combining several models that describe phenomena at each of several length scales, ranging from the nanometer to the meter. This model is described and preliminary results are discussed.
Date: July 15, 1993
Creator: Jennings, H. M. & Xi, Yunping
System: The UNT Digital Library
Automatic contact in DYNA3D for vehicle crashworthiness (open access)

Automatic contact in DYNA3D for vehicle crashworthiness

This paper presents a new formulation for the automatic definition and treatment of mechanical contact in explicit nonlinear finite element analysis. Automatic contact offers the benefits of significantly reduced model construction time and fewer opportunities for user error, but faces significant challenges in reliability and computational costs. This paper discusses in detail a new four-step automatic contact algorithm. Key aspects of the proposed method include automatic identification of adjacent and opposite surfaces in the global search phase, and the use of a smoothly varying surface normal which allows a consistent treatment of shell intersection and corner contact conditions without ad-hoc rules. The paper concludes with three examples which illustrate the performance of the newly proposed algorithm in the public DYNA3D code.
Date: July 15, 1993
Creator: Whirley, R. G. & Engelmann, B. E.
System: The UNT Digital Library
The Gamma-ray Galactic Diffuse Radiation and CerenkovTelescopes (open access)

The Gamma-ray Galactic Diffuse Radiation and CerenkovTelescopes

None
Date: July 15, 1995
Creator: Chardonnet, P.; Salati, P.; Slik, J.; Grenier, I. & Smoot, George F.
System: The UNT Digital Library
A Historical Review of WIPP Backfill Development (open access)

A Historical Review of WIPP Backfill Development

Backfills have been part of Sandia National Laboratories' [Sandia's] Waste Isolation Pilot Plant [WIPP] designs for over twenty years. Historically, backfill research at Sandia has depended heavily on the changing mission of the WIPP facility. Early testing considered heat producing, high level, wastes. Bentonite/sand/salt mixtures were evaluated and studies focused on developing materials that would retard brine ingress, sorb radionuclides, and withstand elevated temperatures. The present-day backfill consists of pure MgO [magnesium oxide] in a pelletized form and is directed at treating the relatively low contamination level, non-heat producing, wastes actually being disposed of in the WIPP. It's introduction was motivated by the need to scavenging CO{sub 2} [carbon dioxide] from decaying organic components in the waste. However, other benefits, such as a substantial desiccating capacity, are also being evaluated. The MgO backfill also fulfills a statutory requirement for assurance measures beyond those needed to demonstrate compliance with the US Environmental Protection Agency [EPA] regulatory release limits. However, even without a backfill, the WIPP repository design still operates within EPA regulatory release limits.
Date: July 15, 1999
Creator: Brush, L.H.; Krumhansl, J.L.; Molecke, M.A. & Papenguth, H.W.
System: The UNT Digital Library
Security Services Discovery by ATM Endsystems (open access)

Security Services Discovery by ATM Endsystems

This contribution proposes strawman techniques for Security Service Discovery by ATM endsystems in ATM networks. Candidate techniques include ILMI extensions, ANS extensions and new ATM anycast addresses. Another option is a new protocol based on an IETF service discovery protocol, such as Service Location Protocol (SLP). Finally, this contribution provides strawman requirements for Security-Based Routing in ATM networks.
Date: July 15, 1999
Creator: Sholander, Peter & Tarman, Thomas
System: The UNT Digital Library
Physics with the collider detectors at RHIC and the LHC (open access)

Physics with the collider detectors at RHIC and the LHC

On January 8, 1995, over 180 participants gathered to hear the QM95 preconference workshop on `Physics with the Collider Detectors at RHIC and the LHC`. The goal was to bring together the experimentalists from a wide community of hadron and heavy ion collider detector collaborations. The speakers were encouraged to present the current status of their detectors, with all the blemishes, and the audience was encouraged to share their successes and failures in approaching similar detector design issues. The presentations were excellent and the discussions were lively and stimulating. The editors hope that the reader will find these proceedings to be equally stimulating. Separate abstracts have been submitted to the energy database from articles in this report.
Date: July 15, 1995
Creator: Thomas, J. & Hallman, T.
System: The UNT Digital Library
A novel condenser for EUV lithography ring-field projection optics (open access)

A novel condenser for EUV lithography ring-field projection optics

A condenser for a ring-field extreme ultra-violet (EUV) projection lithography camera is presented. The condenser consists of a gently undulating mirror, that we refer to as a ripple plate, and which is illuminated by a collimated beam at grazing incidence. The light is incident along the ripples rather than across them, so that the incident beam is reflected onto a cone and subsequently focused on to the arc of the ring field. A quasistationary illumination is achieved, since any one field point receives light from points on the ripples, which are distributed throughout the condenser pupil. The design concept can easily be applied to illuminate projection cameras with various ring-field and numerical aperture specifications. Ray-tracing results are presented of a condenser for a 0.25 NA EUV projection camera.
Date: July 15, 1999
Creator: Chapman, H. & Nugent, K. A.
System: The UNT Digital Library
A limit on {sigma} {center_dot} BR (B{sub c}{sup {+-}} {yields} J/{psi} + {pi}{sup {+-}})/{sigma} {center_dot} BR(B{sub u}{sup {+-}} {yields} J/{psi} + K{sup {+-}}) in {radical}s = 1.8 TeV proton-antiproton collisions (open access)

A limit on {sigma} {center_dot} BR (B{sub c}{sup {+-}} {yields} J/{psi} + {pi}{sup {+-}})/{sigma} {center_dot} BR(B{sub u}{sup {+-}} {yields} J/{psi} + K{sup {+-}}) in {radical}s = 1.8 TeV proton-antiproton collisions

We report on the results of a search for the B{sub c} (b{bar c}) meson in the decay B{sub c}{sup +-} {yields} J/{psi} + {pi}{sup +-}. This search is guided by a control sample of decays of B{sub u} mesons to J/{psi} + K and uses {approx_equal} 75pb{sup -1} of data collected at the Collider Detector Facility (CDF) at Fermilab. The lifetime of the B{sub c} meson is unknown, so the 95% confidence level limit on {sigma} {center_dot} BR(B{sub c} {yields} {psi} + {pi})/{sigma} {center_dot} BR(B{sub u} {yields} {psi} + K) is obtained as a function of the B{sub c} lifetime.
Date: July 15, 1995
Creator: Abe, F.
System: The UNT Digital Library
Using a straightness reference in obtaining more accurate surface profiles from a Long Trace Profiler (open access)

Using a straightness reference in obtaining more accurate surface profiles from a Long Trace Profiler

The Long Trace Profiler has found significant applications in measuring the surfaces of synchrotron optics. However, requirements of small slope errors at all spatial wavelengths of the synchrotron optics mandate more accurate slope measurements. A straightness reference for the Long Trace Profiler greatly increases the accuracy of the instrument. Methods of using the straightness reference by interpreting the sequential interference patterns are discussed and results of measurements are presented.
Date: July 15, 1991
Creator: Irick, S.C.; McKinney, W.R. (Lawrence Berkeley Lab., CA (United States)); Lunt, D.L.J. (Tucson Optical Research Corp., AZ (United States)) & Takacs, P.Z. (Brookhaven National Lab., Upton, NY (United States). Instrumentation Div.)
System: The UNT Digital Library
Varied line-space gratings and applications (open access)

Varied line-space gratings and applications

This paper presents a straightforward analytical and numerical method for the design of a specific type of varied line-space grating system. The mathematical development will assume plane or nearly-plane spherical gratings which are illuminated by convergent light, which covers many interesting cases for synchrotron radiation. The gratings discussed will have straight grooves whose spacing varies across the principal plane of the grating. Focal relationships and formulae for the optical grating-pole-to-exist-slit distance and grating radius previously presented by other authors will be derived with a symbolic algebra system. It is intended to provide the optical designer with the tools necessary to design such a system properly. Finally, some possible advantages and disadvantages for application to synchrotron to synchrotron radiation beamlines will be discussed.
Date: July 15, 1991
Creator: McKinney, W. R.
System: The UNT Digital Library
Production and remediation of low-sludge, simulated Purex waste glasses, 1: Effects of sludge oxide additions on melter operation (open access)

Production and remediation of low-sludge, simulated Purex waste glasses, 1: Effects of sludge oxide additions on melter operation

Glass produced during the Purex 4 campaigns of the Integrated Defense Waste Processing Facility (DWPF) Melter System (IDMS) and the 774 Research Melter contained a lower fraction of sludge components than targeted by the Product Composition Control System (PCCS). Purex 4 glass was more durable than the benchmark (EA) glass, but less durable than most simulated SRS high-level waste glasses. Also, Purex 4 glass was considerably less durable than predicted by the algorithm which will be used to control production of DWPF glass. A melter run was performed using the 774 Research Melter to determine if the initial PCCS target composition determined for Purex 4 would produce acceptable glass whose durability could be accurately modeled by Hydration Thermodynamics. Reagent grade oxides and carbonates were added to Purex 4 melter feed stock to simulate a higher sludge loading. Each canister of glass produced was sampled and the composition, crystallinity, and durability was determined. This document details the melter operation and composition and crystallinity analyses.
Date: July 15, 1993
Creator: Ramsey, W. G.
System: The UNT Digital Library
Two portable parallel tridiagonal solvers (open access)

Two portable parallel tridiagonal solvers

Many scientific computer codes involve linear systems of equations which are coupled only between nearest neighbors in a single dimension. The most common situation can be formulated as a tridiagonal matrix relating source terms and unknowns. This system of equations is commonly solved using simple forward and back substitution. The usual algorithm is spectacularly ill suited for parallel processing with distributed data, since information must be sequentially communicated across all domains. Two new tridiagonal algorithms have been implemented in FORTRAN 77. The two algorithms differ only in the form of the unknown which is to be found. The first and simplest algorithm solves for a scalar quantity evaluated at each point along the single dimension being considered. The second algorithm solves for a vector quantity evaluated at each point. The solution method is related to other recently published approaches, such as that of Bondeli. An alternative parallel tridiagonal solver, used as part of an Alternating Direction Implicit (ADI) scheme, has recently been developed at LLNL by Lambert. For a discussion of useful parallel tridiagonal solvers, see the work of Mattor, et al. Previous work appears to be concerned only with scalar unknowns. This paper presents a new technique which treats …
Date: July 15, 1994
Creator: Eltgroth, P. G.
System: The UNT Digital Library
Cement-aggregate compatibility and structure property relationships including modelling (open access)

Cement-aggregate compatibility and structure property relationships including modelling

The role of aggregate, and its interface with cement paste, is discussed with a view toward establishing models that relate structure to properties. Both short (nm) and long (mm) range structure must be considered. The short range structure of the interface depends not only on the physical distribution of the various phases, but also on moisture content and reactivity of aggregate. Changes that occur on drying, i.e. shrinkage, may alter the structure which, in turn, feeds back to alter further drying and shrinkage. The interaction is dynamic, even without further hydration of cement paste, and the dynamic characteristic must be considered in order to fully understand and model its contribution to properties. Microstructure and properties are two subjects which have been pursued somewhat separately. This review discusses both disciplines with a view toward finding common research goals in the future. Finally, comment is made on possible chemical reactions which may occur between aggregate and cement paste.
Date: July 15, 1993
Creator: Jennings, H. M. & Xi, Y.
System: The UNT Digital Library
Phase transformations and phase relations in Ti{sub 50}Pd{sub (50-x)}TM{sub x} alloys (open access)

Phase transformations and phase relations in Ti{sub 50}Pd{sub (50-x)}TM{sub x} alloys

The effect of transition metal (TM) substitution for Pd in Ti{sub 5O}Pd{sub (50-x}TM{sub x} alloys with x between 5 and 37.5 at.% and TM = V, Cr, Mn and Fe are being characterized by transmission electron microscopy and First-Principles Alloy Theory modeling. The goal is to obtain detailed structural information related to the ternary phase relations and transformations that are necessary for effective shape-memory alloy development. Thus far, the authors have found that the tend to have pseudobinary eutectoid-like configurations with a terminal TiPd and a non-close-packed long period ordered structure type crystal structure) based on the stoichiometry Ti{sub 2}PdTM. The systems exhibit a conventional martensitic transformation, as well as a new type of displacive transformation that shear-modulates B2 to produce a periodically distorted, but non-close-packed metastable product phase.
Date: July 15, 1994
Creator: Schwartz, A. J.; Sluiter, M. H.; Harmon, B. N. & Tanner, L. E.
System: The UNT Digital Library