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Effect of deposits on corrosion of materials exposed in the Coal-Fired Flow Facility (open access)

Effect of deposits on corrosion of materials exposed in the Coal-Fired Flow Facility

Candidate heat exchanger materials tested in the Low Mass Flow train at the Coal-Fired Flow Facility (CFFF) at Tullahoma, TN. were analyzed to evaluate their corrosion performance. Tube specimens obtained at each foot of the 14-ft-long Unbend tubes were analyzed for corrosion-scale morphologies, scale thicknesses, and internal penetration depths. Results developed on 1500- and 2000- h exposed specimens were correlated with exposure temperature. In addition, deposit materials collected at several locations in the CFFF were analyzed in detail to characterize the chemical and physical properties of the deposits and their influence on corrosion performance of tube materials.
Date: May 1, 1993
Creator: Natesan, K.
System: The UNT Digital Library
Modeling and measurement of the ALS U5 undulator end magnetic structures (open access)

Modeling and measurement of the ALS U5 undulator end magnetic structures

A brief summary of the activities of the traveler, information derived, and impressions gained while participating in the Japanese Science and Technology Agency's Forum for Multi-Disciplinary Research is given. A visit to the construction site of SPring 8, the new Japanese synchrotron radiation facility, also is described.
Date: May 1, 1993
Creator: Humphries, D.; Halbach, K.; Hoyer, E.; Kincaid, B.; Marks, S. & Schlueter, R.
System: The UNT Digital Library
Radiation effects on optoelectronic analog link for particle detectors (open access)

Radiation effects on optoelectronic analog link for particle detectors

The successful operation of an optoelectronic analog link for transfer of particle detector signals in high radiation area requires a detailed radiation damage study. We present at this conference the study of Ti: LiNbO[sub 3] optical modulators with gamma-rays and neutrons.
Date: May 1, 1993
Creator: Tsang, T.
System: The UNT Digital Library
Electroweak results from D0 (open access)

Electroweak results from D0

Preliminary results from D0 are presented on properties of the W[sup [plus minus]] and Z[sup 0] electroweak gauge bosons, using final states containing electrons and muons. In particular, preliminary measurements of the W[sup [plus minus]] and Z[sup 0] production cross sections with decay into final states containing electrons are shown and a status report on the determination of M[sub w]/M[sub z] is given.
Date: May 1, 1993
Creator: Demarteau, M.
System: The UNT Digital Library
The ALS Gun Electronics system (open access)

The ALS Gun Electronics system

The ALS Gun Electronics system has been designed to accommodate gun with a custom made socket and high speed electronics circuit which is capable of producing single and multiple electron bunches with time jitters measured at better than 50 PS. The system generates the gated RF signal at ground level before sending it up to the 120 KV-biased gun deck via a fiber optic cable. The current pulse width as a function of grid bias, using an Eimac 8847A planar triode simulating an electron gun, was measured to show the relationship between the two parameters.
Date: May 1, 1993
Creator: Lo, C. C.
System: The UNT Digital Library
Spectral quality of ALS U5. 0 undulator and field error effects (open access)

Spectral quality of ALS U5. 0 undulator and field error effects

The first insertion device of the Advanced Light Source (ALS), a U5.0 undulator, has been carefully adjusted and qualified with a specially designed magnetic measurement system. The magnetic field of the undulator has been fully mapped at a series of gaps with very high accuracy. Based upon these measured field data, the authors evaluate the radiation spectral quality of this device in terms of an ideal sinusoidal device and examine the field error effects. Moreover, statistical correlation between the field errors and radiation degradation is examined by using the large quantity of magnetic field data sets accumulated in the process of adjusting and qualifying the U5.0 undulator.
Date: May 1, 1993
Creator: Wang, C.; Marks, S. & Kincaid, B.
System: The UNT Digital Library
A lower cost development path for heavy ion fusion (open access)

A lower cost development path for heavy ion fusion

If two features of the inertial fusion process are exploited successfully, they can lead to significantly lower costs for demonstrating the feasibility of commercial electric power production from this source of energy. First, fusion capsule ignition and burn physics is independent of reaction chamber size and hydrodynamically-equivalent capsules can be designed to perform at small yield, exactly as they do at large yield. This means that an integrated test of all power plant components and feasibility tests of various reaction chamber concepts can be done at much smaller sizes (about 1--2 m first wall radius) and much lower powers (tens of MWs) than magnetic fusion development facilities such as ITER. Second, the driver, which is the most expensive component of currently conceived IFE development facilities, can be used to support more than one experiment target chamber/reactor (simultaneously and/or sequentially). These two factors lead to lower development facility costs, modular facilities, and the planning flexibility to spread costs over time or do several things in parallel and thus shorten the total time needed for development of Inertial Fusion Energy (IFE). In this paper the authors describe the general feature of a heavy ion fusion development plan that takes advantage of upgradable …
Date: May 19, 1993
Creator: Hogan, W. J. & Meier, W. R.
System: The UNT Digital Library
Emittance measurement and modeling of the ALS 50 MeV linac to booster line (open access)

Emittance measurement and modeling of the ALS 50 MeV linac to booster line

The Twiss parameters and emittance have been measured for the ALS LINAC through non-linear {chi}{sup 2} fitting of the measured beam size (fixed location) vs. focal strength of a quadrupole triplet. The obtained values have been used to calculate the expected beam size and dispersion along the linac-to-booster transport line giving good agreement with measurements. The efforts resulted in superior injection into the booster.
Date: May 1, 1993
Creator: Bengtsson, J.; Leemans, W. & Byrne, T.
System: The UNT Digital Library
Condensed-phase thermal decomposition of TATB investigated by atomic force microscopy (AFM) and simultaneous thermogravimetric modulated beam mass spectrometry (STMBMS) (open access)

Condensed-phase thermal decomposition of TATB investigated by atomic force microscopy (AFM) and simultaneous thermogravimetric modulated beam mass spectrometry (STMBMS)

A combination of techniques has been used to investigate the condensed-phase thermal decomposition of TATB. STMBMS has been used to identify the thermal decomposition products and their temporal correlation`s. These experiments have shown that the condensed-phase decomposition proceeds through several autocatalytic pathways. Both low and high molecular weight decomposition products have been identified. Mono-, di- and tri-furazans products have been identified and, their temporal behaviors are consistent with a stepwise loss of water. AFM has been used to correlate the decomposition chemistry with morphological changes occurring as a function of heating. Patches of small 25-140 nm round holes were observed throughout the lattice of TATB crystals that were heated briefly to 300C. It is likely that these holes show where decomposition reactions have started. Evidence of decomposition products have been seen in TATB that has been held at 250C for one hour.
Date: May 1, 1993
Creator: Land, T. A.; Siekhaus, W. J.; Foltz, M. F. & Behrens, R. Jr.
System: The UNT Digital Library
Spool pieces at the SSCL (open access)

Spool pieces at the SSCL

The basic features of the Superconducting Super Collider lattice are the two beamlines formed by superconducting dipoles (7736) and quadrupoles (1564). The dipoles constraint two 20 TeV proton beams into counterrotating closed orbits of 86.2 km. The quadrupoles (FODO) require cryogenic cooling the LHe temperatures. This requirement isolates the main magnets from the outside world. The interface required, the spool, is a crucial component of superconducting lattice design and machine operation. There are over 1588 spools in the Super Collider. We present hear SSCL spool designs which consist of (1) housing for superconducting closed orbit and multipole correction magnets, (2) cryogenic function, magnet quench protection, system power, and instrumentation interfaces, and (3) cold to warm transitions for ware magnet and warm instrumentation drift spaces.
Date: May 1, 1993
Creator: Clayton, T.; Cai, Y.; Smellie, R. & Stampke, S.
System: The UNT Digital Library
Using transient waveform recorders to measure and store beam parameters (open access)

Using transient waveform recorders to measure and store beam parameters

Transient waveform digitizers are used to measure the tunes in the Stanford Liner Collider (SLC) damping rings. Since the beam injection and extraction from these rings occurs at a high rate (120 Hz) and because of the stringent extracted beam stability requirements, simpler asynchronous resonant excitation spectrum analyzer measurements are not possible. The beam position monitor signals are processed, digitized, and a Fast Fourier Transform (FFT) is applied to find the tunes. The coherent beam motion at injection, even though it damps quickly, is large enough to provide a strong tune signal. Recently, this technique has also been applied to several longitudinal signals. The results from these monitors are recorded at six-minute intervals in the SLC control system history buffers. This paper will describe the hardware setup and the software used to process the data, and will present some of the results.
Date: May 1, 1993
Creator: Stege, R. E. Jr.; Jobe, R. K. & Ross, M.
System: The UNT Digital Library
A role for on-site chemical analysis to support CWC inspections (open access)

A role for on-site chemical analysis to support CWC inspections

The CWC, when it enters into force, will be unique among arms control treaties in the detail of its verification provisions. Each of the treaty provisions will, at least in principle, be monitored by on-site inspections classified as either routine or challenge. In either type of inspection, inspectors are allowed to collect physical samples for chemical analysis. Available analytical instruments have the resolution and the sensitivity to isolate, detect and identify chemical species present in concentrations of less than parts per trillion in many cases. These capabilities provide powerful tools for CWC inspectors. They also drastically increase the risk for compromise of sensitive information that is not relevant to the CWC. This information may deal with national security issues or confidential business issues. The challenge then is to strike the proper balance between the protection of legitimately sensitive information and providing adequate analytical support to CWC inspectors. The capabilities and limitations of sample collection and chemical analysis have been explored in a number of field experiments at both US government and US industrial facilities. The results of these experiments have led to a better appreciation of the risk to sensitive information and the generation and some testing of methods to …
Date: May 1, 1993
Creator: McGuire, R. R. & Raber, E.
System: The UNT Digital Library
Energy and luminosity limits of hadron supercolliders (open access)

Energy and luminosity limits of hadron supercolliders

Extending the frontiers of experimental high energy physics in a manner that maximizes discovery potential requires the building accelerators of ever higher particle energies and luminosities. Both hadron and e{sup +}e{sup {minus}} colliders have been proposed for this role. Based on a self-consistent computational model, this paper explores the features of hadron supercolliders beyond the SSC. The application of the presently available accelerator technologies embodied in the designs of the LHC and SSC to an ELOISATRON operating at 100 TeV per beam would yield a collider with a luminosity of 10{sup 34} cm{sup {minus}2} s{sup {minus}1}. Even higher energies and luminosities are clearly possible. The paper concludes with an examination of the ultimate potential of synchrontron-based colliders to explore PeV energies.
Date: May 1, 1993
Creator: Barletta, W. A.
System: The UNT Digital Library
Infrared (IR) vs x-ray power generation in the SLAC Linac Coherent Light Source (LCLS) (open access)

Infrared (IR) vs x-ray power generation in the SLAC Linac Coherent Light Source (LCLS)

The LCLS, a Free-Electron Laser (FEL) designed for operation at a first harmonic energy of 300 eV ({lambda} {congruent} 40{Angstrom}) in the Self-Amplified Spontaneous Emission (SASE) regime, will utilize electron bunches compressed down to durations of <0.5ps, or lengths of <150 {mu}. It is natural to inquire whether coherent radiation of this (and longer) wavelength will constitute a significant component of the total coherent output of the FEL. In this paper a determination of a simple upper bound on the IR that can be generated by the compressed bunches is outlines. Under the assumed operating parameters of the LCLS undulator, it is shown that that IR component of the coherent output should be strongly dominated by the x-ray component.
Date: May 1, 1993
Creator: Tatchyn, R.
System: The UNT Digital Library
Low emittance 0.8A K{sup +} ion source for the LBL Induction Linac System Experiment (ILSE) (open access)

Low emittance 0.8A K{sup +} ion source for the LBL Induction Linac System Experiment (ILSE)

A high current injector for heavy ion fusion presently under construction at Lawrence Berkeley Laboratory requires large sources of up to 17 an in diameter and total potassium ion current of 790 mA with a low normalized transverse emittance of less than 0.5 mm-mr. A 1 in. diameter hot alumina silicate (zeolite) source was fabricated and tested in the injector setup of SBTE, an existing facility at LBL. Initial measurements showed a maximum space charge limited ion current of 95 mA. The corresponding density of 19 mA/cm{sup 2} was limited by the source diode optics and not be the source emission. The density required for the high current injector is 4 mA/cm{sup 2}. The normalized emittance was measured to be 0.06 mm-mrad, corresponding to a transverse temperature of 0.2 eV. Non-destructive life tests showed that the source can be operated under continuous operating conditions of the high current injector for more than a month (twenty eight-hour days, with 1 {mu}s long pulses at 1 Hz). D.C. destructive life tests showed that {approximately}30% of the total stored K can be ionized and extracted, allowing, in principle, for years of operation for the high current injector. Furthermore, we shall describe the extension …
Date: May 1, 1993
Creator: Eylon, S.; Henestroza, E.; Chupp, W. W. & Yu, S.
System: The UNT Digital Library
Design of the ALS transverse coupled-bunch feedback system (open access)

Design of the ALS transverse coupled-bunch feedback system

Calculations of transverse coupled bunch growth rates in the Advanced Light Source (ALS), a 1.5 GeV electron storage ring for producing synchrotron radiation, indicate the need for damping via a transverse feedback (TFB) system. We present the design of such a system. The maximum bunch frequency is 500 MHz, requiring that the FB system have a broadband response of at least 250 MHz. We described, in detail, the choice of broadband components such as kickers, pickups, power amplifiers, and electronics.
Date: May 1, 1993
Creator: Barry, W.; Byrd, J. M.; Corlett, J. N.; Hinkson, J.; Johnson, J.; Lambertson, G. R. et al.
System: The UNT Digital Library
Simulation of the ALS longitudinal multibunch feedback system (open access)

Simulation of the ALS longitudinal multibunch feedback system

Longitudinal coupled bunch growth rates in the Advanced Light Source (ALS), a 1.5 GeV electron storage ring for producing synchrotron radiation, indicate the need for damping via a feedback (FB) system. The design of the system is based on the proposed PEP-II longitudinal FB system which uses a digital filter to provide the required phase and amplitude response. We report the results of a detailed computer simulation of the FB system including single particle longitudinal beam dynamics, measured RF cavity fundamental and higher order modes, and response of major FB components such as the power amplifier and kicker. The simulation addresses issues such as required FB power and gain, noise, digital filter effects, and varying initial bunch conditions.
Date: May 1, 1993
Creator: Byrd, J.
System: The UNT Digital Library
Physics Detector Simulation Facility Phase II system software description (open access)

Physics Detector Simulation Facility Phase II system software description

This paper presents the Physics Detector Simulation Facility (PDSF) Phase II system software. A key element in the design of a distributed computing environment for the PDSF has been the separation and distribution of the major functions. The facility has been designed to support batch and interactive processing, and to incorporate the file and tape storage systems. By distributing these functions, it is often possible to provide higher throughput and resource availability. Similarly, the design is intended to exploit event-level parallelism in an open distributed environment.
Date: May 1, 1993
Creator: Scipioni, B.; Allen, J.; Chang, C.; Huang, J.; Liu, J.; Mestad, S. et al.
System: The UNT Digital Library
Poroelasticity of rock (open access)

Poroelasticity of rock

Poroelasticity is the theoretical framework used to describe the coupled processes which occur when a fluid bearing porous material is deformed by a stress field. The theoretical basis for the treatment of problems in poroelasticity has been derived in an extensive body of work over the last fifty years, most notably by Biot. Many of Biot`s successors have attempted to find relationships between the physical properties of the material to be analyzed and the Biot coefficients. Our approach to this problem has both theoretical and experimental components. The general theoretical objective is to produce estimates of the Biot coefficients which are more realistic e.g.. are not limited by assumptions which preclude their use for real earth materials. Experiments are designed to measure the coefficients (or parameters which are directly related to them) which have not been measured as yet to provide new insight for improving the theory of poroelasticity. The experimental program is designed to determine the mechanical and transport properties of a well characterized set of synthetic and natural sandstones from static to ultrasonic frequencies.
Date: May 13, 1993
Creator: Bonner, B. P.; Berge, P. A.; Berryman, J. G. & Wang, H. F.
System: The UNT Digital Library
Processing of YBCO superconductors for improved levitation force (open access)

Processing of YBCO superconductors for improved levitation force

One objective of the ANL superconductor program is to develop improved processing methods for production of YBCO superconductors with higher levitation forces suitable for low-friction, superconductor/permanent-magnet bearings and flywheel-energy-storage applications. From the standpoint of these applications, melt-processed bulk YBCO superconductors are of considerable interest. Levitation force and flux-pinning properties depend on microstructural features of the superconductors. We have added several chemical species to YBCO to alter the microstructure and have used a seeding technique to induce crystallization during melt processing. In this paper, we discuss the effects of various process parameters, additives, and a seeding technique on the properties of melt-processed bulk YBCO samples and compare the results with solid-state-sintered superconductors.
Date: May 1, 1993
Creator: Balachandran, U. & Zhong, W.
System: The UNT Digital Library
Beam based alignment of the SLC final focus sextupoles (open access)

Beam based alignment of the SLC final focus sextupoles

The strong demagnification inherent in final focus systems requires local cancellation of the resulting chromaticty. Strong sextupole pair separated by a -I transform are positioned {pi}/2 in the betatron phase away from the Interaction Point (IP) in order to cancel chromatic aberrations primarily due to the final quadrupoles. Sextupole alignment is critical in order to provide orthogonal tuning of the chromaticty and, in the case of the SLC, to limit the third and higher order optical aberrations generated from misaligned and `nested` horizontal and vertical sextupole pairs. Reported here is a novel technique for aligning the beam centroid to the sextupole centers, which uses measurements of the criticality dependent parameter - the beam size at the IP. Results for the SLC final focus sextupoles are presented, where a resolution of <50 {mu}m is achieved.
Date: May 1, 1993
Creator: Emma, P.; Irwin, J.; Phinney, N.; Raimondi, P.; Toge, N.; Walker, N. J. et al.
System: The UNT Digital Library
Applications and Comparisons of Methods of Computing the S Matrix of 2-Ports (open access)

Applications and Comparisons of Methods of Computing the S Matrix of 2-Ports

We report on the application of three different methods of computing the S Matrix for 2-port microwave circuits. The four methods are modal expansions with field matching across boundaries, time domain integration of Maxwell`s equations as implemented in MAFIA, HFSS (high frequency structure simulator), and the KKY frequency domain method. Among the applications to be described are steps in rectangular waveguides and irises in waveguides.
Date: May 1, 1993
Creator: Jones, R. M.; Ko, Kwok; Tantawi, S.; Kroll, N. & Yu, D.
System: The UNT Digital Library
High-order sum and difference-frequency generation in helium (open access)

High-order sum and difference-frequency generation in helium

High-order harmonic generation provides a new method for generating coherent, XUV radiation. These harmonics are characterized by a rapid, pertubative drop at low orders, followed by a broad plateau extending to photon energies of 150 eV in the lighter, rare gas atoms. An experimentally observed limit coincides with the theoretical limit for harmonic generation in neutral atoms given by the expression E{sub c}(eV)=IP(0)+3U{sub p}(I), where E{sub c} is the energy cutoff of the harmonic plateau, IP(O) is the field-free ionization potential and U{sub p} is the electron quiver energy at the maximum intensity, I seen by the atom. As part of an effort to develop this technique into a general purpose XUV source, extensive work to understand the phase-matching between the harmonic and driving fields, and the resulting effect on the conversion efficiency, angular distribution and spectral brightness has been undertaken at several. Though, certain aspects of the harmonically generated radiation such as the polarization, relative strength of a given harmonic, and the plateau extent, are defined by the single atom-field interaction. Specifically, the single-atom harmonic spectrum is determined primarily by the interaction of a driven, quasi-free electron with the atomic potential. Using two, independent fields one can affect the …
Date: May 12, 1993
Creator: Crane, J. K. & Perry, M. D.
System: The UNT Digital Library
Flat beams in the SLC (open access)

Flat beams in the SLC

The Stanford Linear collider was designed to operate with round beams; horizontal and vertical emittance made equal in the damping rings. The main motivation was to facilitate the optical matching through beam lines with strong coupling elements like the solenoid spin rotator magnets and the SLC arcs. Tests in 1992 showed that ``flat`` beams with a vertical to horizontal emittance ratio of around 1/10 can be successfully delivered to the end of the linac. Techniques developed to measure and control the coupling of the SLC arcs allow these beams to be transported to the Interaction Point (IP). Before flat beams could be used for collisions with polarized electrons, a new method of rotating the electron spin orientation with vertical arc orbit bumps had to be developed. Early in the 1993 run, the SLC was switched to ``flat`` beam operation. Within a short time the peak luminosity of the previous running cycle was reached and then surpassed. The average daily luminosity is now a factor of about two higher than the best achieved last year. In the following we present an overview of the problems encountered and their solutions for different parts of the SLC.
Date: May 1, 1993
Creator: Adolphsen, C.; Barklow, T. & Burke, D.
System: The UNT Digital Library