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Crossing angle collision and lifetime: Simulations, analysis, measurements and more simulations
To achieve the high luminosity required by heavy quark factories, multibunch operation is almost the only choice. The key to gain luminosity in multibunch operation is to reduce the bunch spacing. Therefore, colliding beams with a crossing angle becomes the favorite interaction region scheme. The introduction of a crossing angle in e{sup +}e{sup {minus}} colliders causes non-linear coupling between horizontal motion and longitudinal motion. This is illustrated in Figure 1. The beam-beam kick occurs when the particle passes the center of the opposing bunch. The strength of the kick, {Delta}r{prime} = F(r), is a nonlinear function of the distance, r, between the particle and the center of the opposite bunch. In head-on collisions, r is the transverse displacement, and the kick is in the transverse plane, so that the process is nonlinear but not influenced by the longitudinal motion. In collisions with a crossing angle, however, r is a function of longitudinal displacement, s, and the crossing angle, F, as well as transverse displacement. The distance r between the test particle and the bunch center can be written.
Date:
July 1, 1995
Creator:
Chen, T.
Object Type:
Article
System:
The UNT Digital Library
Summary of Working Group I - beam-beam instability with crossing angle
This report is a summary report from a panel addressing the problem of beam-beam instability in colliding beams at finite crossing angles. This problem arises in the process of increasing luminosity in large circular particle factories. The primary means of increasing luminosity comes down to increasing the number of bunches in each beam, while decreasing the spacing between bunches. This situation favors finite crossing angle collision schemes. However such schemes allow synchro-betatron coupling, as transverse and longitudinal energies are mixed. The authors summarize their discussions on this problem, and the present state of experience with such schemes.
Date:
June 1, 1995
Creator:
Chen, T.
Object Type:
Article
System:
The UNT Digital Library
Final report on the Groundwater Isotope Project in the Brentwood Region of East Contra Costa County, California
Groundwater in the Brentwood region has been characterized using isotope hydrology techniques and have addressed resource issues regarding the future sustainability of groundwater, maintenance of existing supplies, and exploration of new supplies. The stable isotopes of oxygen and hydrogen indicate that groundwater is derived from two sources: ancient rain recharge, and recharge of agricultural irrigation water. Rain derived groundwater ages range from <1000 to {approximately}12,000 years old. Agricultural recharge groundwater is <80 years and has recharged much of the basin on average to {approximately}125 fbs. The agricultural water recharges >10 times faster than natural rain water and hence, represents the principal recharge component. The agricultural recharge at the present time provides groundwater quantities to the basin that exceed the yearly water supply demand. With increasing urban development and retiring agricultural land, the availability of groundwater will decrease. Safe yield projections for the groundwater have been modeled to show that safe groundwater yields range between 30 to 120 acre-ft/mi{sup 2} per year for a population of 70,000 people. This will only account for {approximately}3 to 11 % of the total water demand. Furthermore, much of this groundwater may need well head treatment for water quality problems.
Date:
May 1, 1995
Creator:
Davisson, M. L. & Campbell, K. R.
Object Type:
Report
System:
The UNT Digital Library
Proceedings of the Planetary Defense Workshop, Lawrence Livermore National Laboratory, California, May 22-26, 1995
None
Date:
May 1, 1995
Creator:
Nuckolls, J.
Object Type:
Article
System:
The UNT Digital Library
Institute of Geophyics and Planetary Physics. Annual report for FY 1994
The Institute of Geophysics and Planetary Physics (IGPP) is a Multicampus Research Unit of the University of California (UC). IGPP was founded in 1946 at UC Los Angeles with a charter to further research in the earth and planetary sciences and in related fields. The Institute now has branches at UC campuses in Los Angeles, San Diego, Riverside, and Irvine and at Los Alamos and Lawrence Livermore national laboratories. The University-wide IGPP has played an important role in establishing interdisciplinary research in the earth and planetary sciences. For example, IGPP was instrumental in founding the fields of physical oceanography and space physics, which at the time fell between the cracks of established university departments. Because of its multicampus orientation, IGPP has sponsored important interinstitutional consortia in the earth and planetary sciences. Each of the six branches has a somewhat different intellectual emphasis as a result of the interplay between strengths of campus departments and Laboratory programs. The IGPP branch at Lawrence Livermore National Laboratory (LLNL) was approved by the Regents of the University of California in 1982. IGPP-LLNL emphasizes research in seismology, geochemistry, cosmochemistry, high-pressure sciences, and astrophysics. It provides a venue for studying the fundamental aspects of these fields, …
Date:
September 29, 1995
Creator:
Ryerson, F.J.
Object Type:
Report
System:
The UNT Digital Library
The January 17, 1994 Northridge Earthquake: Effects on selected industrial facilities and lifelines
Revision 0 of this report is being published in February 1995 to closely mark the one-year anniversary of the Northridge Earthquake. A September 1994 Draft version of the report was reviewed by DOE and NRC, and many of the review comments are incorporated into Revision 0. While this revision of the report is not entirely complete, it is being made available for comment, review, and evaluation. Since the report was written by several authors, sections of the report have slightly different styles. Several sections of Revision 0 are not complete, but are planned to be completed in Revision 1. The primary unfinished section is Section 3.3 on Electric Power Transmission. Other sections of Revision 0, such as Section 4.5.2 on the Energy Technology Engineering Center and 3.2 on Electric Power Generation, will be enhanced with further detailed information as it becomes available. In addition, further data, including processed response spectra for investigated facilities and cataloging of relay performance, will be added to Revision 1 depending upon investigation support. While Revision 0 of this report is being published by LLNL, Revision 1 is planned to be published by EPRI. The anticipated release date for Revision 1 is December 1995. Unfortunately, the …
Date:
February 1, 1995
Creator:
Eli, M. W.; Sommer, S. C.; Roche, T. R. & Merz, K. L.
Object Type:
Report
System:
The UNT Digital Library
Investigation of exfoliation joints in Navajo sandstone at the Zion National Park and in granite at the Yosemite National Park by tectonofractographic techniques
Tectonofractographic techniques have been applied to the study of joint exfoliation in the Navajo sandstone at Zion National Park and in the granite at Yosemite National Park. New types of fracture surface morphologies have been observed which enabled the discerning of incipient joints and consequent fracture growth in these rocks. Incipient jointing in the sandstone is mostly manifested by elliptical and circular fractures (meters to tens meters across) initiating from independent origins. They interfere with each other and grow to larger circular fractures producing exfoliation surfaces up to hundreds of meters across. Less frequently, series of large concentric undulations demonstrate the propagation of a large fracture front producing exfoliation from an individual origin. One such fracture front reveals refraction of undulations at a layer boundary. Certain en echelon fringes surround the joint mirror plane with well defined rims of en echelons and hackles which enable the determination of the tensile fracture stress, {sigma}f. Arches in Zion National Park are ubiquitous in shape and size, revealing stages in their evolution by a mechanical process, which was associated with exfoliation, but independent of local faulting. Exfoliation and arching mostly occurred on vertical surfaces of N-NNW and NE sets of prominent joints, but …
Date:
April 1, 1995
Creator:
Bahat, D.; Grossenbacher, K. & Karasaki, K.
Object Type:
Report
System:
The UNT Digital Library
Increasing waterflood reserves in the Wilmington oil field through improved reservoir characterization and reservoir management. Quarterly technical progress report, March 21, 1995--June 30, 1995
The main objective of this project is the transfer of technologies, methodologies, and findings developed and applied in this project to other operators of Slope and Basin Clastic Reservoirs. This project will study methods to identify sands with high remaining oil saturation and to recomplete existing wells using advanced completion technology. The identification of the sands with high remaining oil saturation will be accomplished by developing a deterministic 3-D geologic model and by using a state of the art reservoir management computer software. The wells identified by the geologic and reservoir engineering work as having the best potential will be logged with a pulsed acoustic cased-hole logging tool. The application of the logging tools will be optimized in the lab by developing a rock-log model. The wells that are shown to have the best oil production potential will be recompleted. The recompletions will be optimized by evaluating short radius and ultra-short radius lateral recompletions. Technical progress is reported for the following tasks: Reservoir characterization; reservoir engineering; 3-D geologic modeling; pulsed acoustic logging; and technology transfer.
Date:
July 26, 1995
Creator:
Sullivan, D.; Clarke, D.; Walker, S.; Phillips, C.; Nguyen, J.; Moos, D. et al.
Object Type:
Report
System:
The UNT Digital Library
Alkali Deposits Found in Biomass Power Plants: A Preliminary Investigation of Their Extent and Nature. Volume 1
Alkali in the ash of annual crop biomass fuels creates serious fouling and slagging in conventional boilers. Even with the use of sorbents and other additives, power plants can only fire limited amounts of these fuels in combination with wood. The National Renewable Energy Laboratory (NREL), US Department of Energy, and the biomass power industry carried out eight full-scale firing tests and several laboratory experiments to study the nature and occurrence of deposits with the goal of increasing the quantities of these biofuels that can be used. This report describes the results of the laboratory and power plant tests that included: tracking and analyzing fuels and deposits by various methods; recording operating conditions; and extensive laboratory testing. The paper describes the occurrence of deposits, fuel and deposit analyses, boiler design and operation, fouling and slagging indicators, and recommendations. 37 refs., 41 figs., 17 tabs.
Date:
April 15, 1995
Creator:
Miles, T. R.; Miles Jr., T. R.; Baxter, L. L.; Bryers, R. W.; Jenkins, B. M. & Oden, L. L.
Object Type:
Report
System:
The UNT Digital Library
He abundance variations in the solar wind: Observations from Ulysses
The Ulysses mission is providing the first opportunity to observe variations in solar wind plasma parameters at heliographic latitudes far removed from the ecliptic plane. We present an overview of the solar wind speed and the variability in helium abundance, [He] data on [He] in six high latitude coronal mass ejections (CMEs), and a superposed epoch analysis of [He] variations at the seven heliospheric current sheet (HCS) crossings made during the rapid-latitude-scan portion of the mission. The differences in the variability of the solar wind speed and [He] in high latitude and equatorial regions are quite striking. Solar wind speed is generally low but highly variable near the solar equator, while at higher latitudes the average speed is quite high with little variability. [He] can vary over nearly two decades at low solar latitudes, while at high latitudes it varies only slightly. In contrast to the high [He] that is commonly associated with CMEs observed in the ecliptic, none of the six high-speed CMEs encountered at high southern heliographic latitudes showed any significant variation in helium content. A superposed epoch analysis of the [He] during all seven HCS crossings made as Ulysses passed from the southern to northern solar hemisphere …
Date:
September 1, 1995
Creator:
Barraclough, Bruce L.; Gosling, John T.; Phillips, John L.; McComas, David J.; Feldman, William C. & Goldstein, Bruce E.
Object Type:
Article
System:
The UNT Digital Library
A map for the thick beam-beam interaction
The authors give a closed-form expression for the thick beam-beam interaction for a small disruption parameter, as typical in electron-positron storage rings. The dependence on transverse angle and position of the particle trajectory as well as the longitudinal position of collision and the waist-modified shape of the beam distribution are included. Large incident angles, as are present for beam-halo particles or for large crossing-angle geometry, are accurately represented. The closed-form expression is well approximated by polynomials times the complex error function. Comparisons with multi-slice representations show even the first order terms are more accurate than a five slice representation, saving a factor of 5 in computation time.
Date:
June 1, 1995
Creator:
Irwin, J. & Chen, T.
Object Type:
Article
System:
The UNT Digital Library
Modeling of ablation by photospallation using the computer program PUFF/DFRACT
In general, macroscopic material failure is a manifestation of irreversible changes at the microscopic level. Many tissues, which may appear to be macroscopically homogeneous, are, at a fundamental microscopic level, a composite material. For example, cornea is composed of a hyaluronic acid matrix in which layers of collagen fibers are overlaid in a crossing pattern. The points where the collagen fibers intersect are potential nucleation sites for microscopic defects, which under the action of tensile stress, nucleate, grow and coalesce to form macroscopic failure planes, or spall planes. Using a model based on microstructural evolution, this paper examines the failure process during photoablation. Specifically, the paper describes a physically motivated, micromechanical model based on the nucleation and growth of spherical voids. This model is then used to simulate photoablation of cornea. Potential for using this model to predict the stress wave and material damage measured by experiment is discussed.
Date:
March 1, 1995
Creator:
Antoun, T.; Seaman, L. & Glinsky, M.E.
Object Type:
Article
System:
The UNT Digital Library
Government Services Information Infrastructure Management
The Government Services Information Infrastructure (GSII) is that portion of the NII used to link Government and its services, enables virtual agency concepts, protects privacy, and supports emergency preparedness needs. The GSII is comprised of the supporting telecommunications technologies, network and information services infrastructure and the applications that use these. The GSII is an enlightened attempt by the Clinton/Gore Administration to form a virtual government crossing agency boundaries to interoperate more closely with industry and with the public to greatly improve the delivery of government services. The GSII and other private sector efforts, will have a significant impact on the design, development, and deployment of the NII, even if only through the procurement of such services. The Federal Government must adopt new mechanisms and new paradigms for the management of the GSII, including improved acquisition and operation of GSII components in order to maximize benefits. Government requirements and applications will continue to evolv. The requirements from government services and users of form affinity groups that more accurately and effectively define these common requirements, that drive the adoption and use of industry standards, and that provide a significant technology marketplace.
Date:
April 1995
Creator:
Cavallini, J. S. & Aiken, R. J.
Object Type:
Article
System:
The UNT Digital Library
Effects of enclosure on the performance of the weak-swirl burner
This paper reports a study of the velocity and scalar characteristics of the weak-swirl burner in enclosures. WSB utilizes a unique aerodynamic mechanism to stabilize lean burning premixed combustion over a wide range of equivalence ratios ({phi}) and power inputs. As the WSB was developed for fundamental research, previous works focused only on open WSBs. Recent success in adapting the WSB to practical use suggests that a better understanding of the WSB in enclosures is required for further development. Laser Doppler anemometry (LDA), and Mie scattering of oil droplets (MSOD), are used to measure the flame flowfields and flame crossing spectra of the WSB with an open flame, enclosed within a quartz cylinder and within a cylinder with a restricted exit. The flame of the enclosed WSB remained extremely stable and did not develop recirculation zones or audible characteristics. The only change observed was a greater divergence of the flowfield upstream of the reaction zone. Neither lengthening the enclosure nor restricting the flow downstream caused any noticeable difference in the operation of the WSB. This work has demonstrated that the WSB should be amenable for adaptation to a wide variety of low NO{sub x} applications.
Date:
October 1, 1995
Creator:
Yegian, D. K. & Cheng, R. K.
Object Type:
Article
System:
The UNT Digital Library
Two Alternate High Gradient Quadrupoles; An Upgraded Tevatron IR and A"Pipe" Design
With the U.S. cancellation of the SSC project, the only large approved hadron accelerator project is CERN's LHC. One of the more critical elements in the performance of a collider is the quadrupole lens at the beam collision points. These quadrupoles, usually referred to as the 'insertion quads' normally form a set of triplets around the interaction region. Their focal power directly affects the luminosity available at the crossing point In order to achieve as high a gradient as possible, the CERN design team has proposed a very efficient high gradient quadrupole which is based on a graded four-layer winding structure. At Fermilab's Tevatron, an upgraded two layer winding quadrupole has been in operation since 1989, and has provided a 50% higher gradient than its predecessor. The quadrupole was basically state of the art when it was designed in 1985. Since then however, improvements have been made in cabling, conductor perfonnance, etc. Naturally, operation of a modernized version of this .design can provide higher capabilities. This improved two layer design can serve as an alternative to the more intricate graded four layer design now envisioned for the LHC, provided it can obtain the proposed gradient. A high gradient quadrupole with …
Date:
April 1, 1995
Creator:
McInturff, A. D.; van Oort, J. M. & Scanlan, R. M.
Object Type:
Report
System:
The UNT Digital Library
Application of conventional laser technology to gamma-gamma colliders
A future e{sup {minus}}e{sup +} (electron-positron) linear collider can be configured with perhaps minimal modification to serve as an {gamma}-{gamma} (gamma-gamma) or a e{sup {minus}}-{gamma} collider. This is accomplished by Compton-backscattering low energy photons (from a laser source) off of the high-energy electron beams prior to the crossing of the electron beams. However, to be competitive with the e{sup {minus}}e{sup +} configuration, the luminosity cannot be compromised in the process. This requires that the laser source deliver a sufficient number of photons per pulse with a pulse format and rate matching that of the electron beams. As it turns out, this requires an average optical power of 5 to 15 kW from the laser which is beyond the current state of the art. In this paper, the authors address how to generate the required pulse format and how the high average power requirement can be met with conventional laser technology. They also address concerns about the survivability of mirrors located near the interaction point. Finally, they list a program of research and development which addresses some of the unknowns in such a system.
Date:
February 1, 1995
Creator:
Clayton, C. E.; Kurnit, N. A. & Meyerhofer, D. D.
Object Type:
Article
System:
The UNT Digital Library
Quantum symmetry and photoreactivity of azabenzenes
The fundamental processes associated with a photochemical reaction are described with reference to experimental properties of azabenzenes. Consideration of both excitation and relaxation processes led to presentation of the symmetry propagator, a unifying principle which maps system fluctuations (perturbations acting on an initial state) with dissipations (transitions to different states), thus directing the energy flow along competing reactive and nonreactive pathways. A coherent picture of relaxation processes including chemical reactions was constructed with the aid of spectroscopic data. Pyrazine (1,4 diazine) possesses vibronically active modes which provide an efficient mechanism for internal conversion to the first excited singlet state, where other promoting modes of the correct symmetry induce both intersystem crossing to the triplet manifold, isomerization through diaza-benzvalene, and chemical reactions through cycloreversion of dewar pyrazine to yield HCN plus an azete. At higher energies simple H atom loss and internal conversion become more predominant, leading to ring opening followed by elimination of methylene nitrile and ground state reaction products. Efficiency of chemical transformations as dissipation mechanisms versus competing fluorescence, phosphorescence and radiationless relaxation was mapped from near ultraviolet to far ultraviolet by photodissociation quantum yields into reaction channels characterized by molecular beam photofragment translational spectroscopy. A reaction path model …
Date:
June 1995
Creator:
Chesko, J. D. M.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Micro-Bunching Diagnostics for the ICA by Coherent Transition Radiation
Here, the authors propose an effective method to detect micro-bunching effects (10 fs bunch length), produced by the ICA interaction, by using the CTR spectrum. The re-bunching of initially energy modulated e-beam passing through a Hydrogen gas cell (ICA interaction) is studied via a Monte Carlo simulation code (STI), as well as in a space-charge dominated region by a multi-particle time domain tracking code (PARMELA). The results show that even in a strong space-charge dominated region the re-bunching effect is still very pronounced. The erosion of bunching due to the space-charge defocusing washes out the final bunching peak only by about 10% (FWHM). The longitudinal distribution of a micro-bunched beam is Fourier analyzed to find the dominant harmonics contributing to the CTR. The CTR spectrum is calculated analytically for the ICA situation. A schematic of the experimental set up is also proposed.
Date:
December 1995
Creator:
Liu, Y.; Bogacz, S. A.; Cline, D. B.; Wang, X. J.; Pogorelsky, I. V. & Kimura, W. D.
Object Type:
Article
System:
The UNT Digital Library
Field Errors in Hybrid Insertion Devices
Hybrid magnet theory as applied to the error analyses usedin the design of Advanced Light Source (ALS) insertion devices isreviewed. Sources of field errors in hybrid insertion devices arediscussed.
Date:
February 3, 1995
Creator:
Schlueter, R.D.
Object Type:
Article
System:
The UNT Digital Library
The PEP-II design
The Stanford Linear Accelerator Center (SLAC), Lawrence Berkeley Laboratory (LBL), Lawrence Livermore National Laboratory (LLNL) Positron Electron Project-II (PEP-II) is a design for a high-luminosity, asymmetric energy, electron-positron colliding beam accelerator that will operate at the center-of-mass energy of the {Upsilon}4S (10.58 GeV). The goal of the design is to achieve a large enough integrated luminosity with a moving center-of-mass reference frame to he able to observe the predicted rare decay modes of the {Upsilon}4S that do not conserve charge parity (CP).
Date:
May 1, 1995
Creator:
Sullivan, M.K.
Object Type:
Article
System:
The UNT Digital Library
Magnetoresistance behavior of UNiGe
The authors have measured the temperature dependences of the magnetoresistance of single-crystalline UNiGe for both parallel (i//B//c-axis) and perpendicular configurations (i//a-axis, B//c-axis) in magnetic fields up to 18 T. Both configurations yield similar magnetoresistance behavior, which emphasizes the strong magnetic contribution to the resistivity in all directions. Crossing magnetic-phase boundaries causes anomalies in the magnetoresistance, which allowed a completion of the previously proposed magnetic phase diagram.
Date:
May 1, 1995
Creator:
Nakotte, H.; Lacerda, A.; Purwanto, A.; Havela, L.; Sechovsky, V.; Prokes, K. et al.
Object Type:
Report
System:
The UNT Digital Library
A synopsis of environmental horizontal wells at the Savannah River Site
Seven horizontal wells for environmental remediation were installed at the Savannah River Site as part of an Integrated Demonstration Project sponsored by the Department of Energy`s Office of Technology Development. The wells were used to demonstrate innovative remediation systems for the clean up of chlorinated organic solvent contamination in groundwater and the vadose zone. The wells were installed in four demonstrations of different horizontal drilling technologies. A short-radius petroleum industry technology, a modified petroleum industry technology (using a down-hole motor), a utility industry technology, and a river crossing technology were demonstrated. The goals of the demonstrations were to show the utility of horizontal wells in environmental remediation and further development of the technology required to install these wells. From the first demonstration in 1988 to the latest in 1991, there was significant evolution in horizontal drilling technology. The main technical challenges in the first demonstration were directional control during drilling and borehole instability. Through advancement of the technology these problems were overcome and did not affect the last demonstration. Those considering the use of horizontal wells for environmental remediation will benefit from the knowledge gained from these demonstrations.
Date:
July 1995
Creator:
Denham, M. E. & Lombard, K. H.
Object Type:
Report
System:
The UNT Digital Library
Center for Beam Physics: 1994--95
The Center for Beam Physics is a multidisciplinary research and development unit in the Accelerator and Fusion Research Division at the Lawrence Berkeley Laboratory of the University of California. At the heart of the Center`s mission is a fundamental quest for mechanisms of acceleration, radiation, transport, and focusing of energy and information. Dedicated to exploring the frontiers of particle and photon beam physics, its primary mission is to promote the science and technology of the production, manipulation, storage, and control of systems of charged particles and photons. This roster and annual report provides a glimpse of the scientists, engineers, technical support, students, and administrative staff that make up the CBP`s team and gives a brief review of the multifaceted activities during 1994 and 1995.
Date:
May 1, 1995
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Alternative-fueled truck demonstration natural gas program: Caterpillar G3406LE development and demonstration
In 1990, the California Energy Commission, the South Coast Air Quality Management District, and the Southern California Gas Company joined together to sponsor the development and demonstration of compressed natural gas engines for Class 8 heavy-duty line-haul trucking applications. This program became part of an overall Alternative-Fueled Truck Demonstration Program, with the goal of advancing the technological development of alternative-fueled engines. The demonstration showed natural gas to be a technically viable fuel for Class 8 truck engines.
Date:
June 1, 1995
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library