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Improving the AGR Fuel Testing Power Density Profile Versus Irradiation-Time in the Advanced Test Reactor (open access)

Improving the AGR Fuel Testing Power Density Profile Versus Irradiation-Time in the Advanced Test Reactor

The Very High Temperature gas-cooled Reactor (VHTR), which is currently being developed, achieves simplification of safety through reliance on ceramic-coated fuel particles. Each TRISO-coated fuel particle has its own containment which serves as the principal barrier against radionuclide release under normal operating and accident conditions. These fuel particles, in the form of graphite fuel compacts, are currently undergoing a series of irradiation tests in the Advanced Test Reactor (ATR) at the Idaho National Laboratory (INL) to support the Advanced Gas-Cooled Reactor (AGR) fuel qualification program. A representive coated fuel particle with an 235U enrichment of 19.8 wt% was used in this analysis. The fuel burnup analysis tool used to perform the neutronics study reported herein, couples the Monte Carlo transport code MCNP, with the radioactive decay and burnup code ORIGEN2. The fuel burnup methodology known as Monte-Carlo with ORIGEN2 (MCWO) was used to evaluate the AGR experiment assembly and demonstrate compliance with ATR safety requirements. For the AGR graphite fuel compacts, the MCWO-calculated fission power density (FPD) due to neutron fission in 235U is an important design parameter. One of the more important AGR fuel testing requirements is to maintain the peak fuel compact temperature close to 1250°C throughout the …
Date: May 1, 2009
Creator: Chang, Gray S.; Petti, David A.; Maki, John T. & Lillo, Misti A.
Object Type: Article
System: The UNT Digital Library
Recent Experience with Electron Lens Beam-Beam Compensation at the Tevatron (open access)

Recent Experience with Electron Lens Beam-Beam Compensation at the Tevatron

Tevatron Electron Lenses (TEL) have reliably demonstrated correction of the bunch-to-bunch tune shift induced by long-range beam-beam interactions. With the commissioning of the new high voltage modulator that became operational in 2008, the electron beam can be pulsed on every bunch of the Tevatron beam. We report on the recent results of beam-beam compensation studies in the high luminosity regime.
Date: May 1, 2009
Creator: Kuznetsov, G.; Saewert, G.; Shiltsev, V.; Valishev, A. & Kamerdzhiev, V.
Object Type: Article
System: The UNT Digital Library
Microstructure, Processing, Performance Relationships for High Temperature Coatings (open access)

Microstructure, Processing, Performance Relationships for High Temperature Coatings

HVOF coatings have shown high resistance to corrosion in fossil energy applications and it is generally accepted that mechanical failure, e.g. cracking or spalling, ultimately will determine coating lifetime. The high velocity oxygen-fuel method (HVOF) for applying coatings is one of the most commercially viable and allows the control of various parameters including powder particle velocity and temperature which influence coating properties, such as residual stress, bond coat strength and microstructure. The mechanical durability of coatings is being assessed using a dual eddy current coil method to monitor crack formation in real time during thermal cycling. Absolute impedence signals from two coils, which interrogate two different areas on the sample, are collected. Crack detection can be determined from the differential signal generated from these absolute signals. The coils are operated at two different frequencies, resulting in two differential signals used for crack detection. Currently this crack detection method is being used to elucidate the influence of thermal cycling temperature and coating thickness on cracking. Recent results (cycles to failure) will be presented for FeAl coatings thermally sprayed (HVOF) onto carbon steel to two coating thicknesses (160 microns and 250 microns thick) and subsequently cycled at temperatures up to 700oC. Thinner …
Date: May 1, 2009
Creator: Lillo, Thomas & Wright, Richard
Object Type: Article
System: The UNT Digital Library
Search for squark production in events with jets, hadronically decaying tau leptons and missing transverse energy at s**(1/2) = 1.96-TeV (open access)

Search for squark production in events with jets, hadronically decaying tau leptons and missing transverse energy at s**(1/2) = 1.96-TeV

A search for supersymmetric partners of quarks is performed in the topology of multijet events accompanied by at least one tau lepton decaying hadronically and large missing transverse energy. Approximately 1 fb-1 of ppbar collision data from the Fermilab Tevatron Collider at a center of mass energy of 1.96 TeV recorded by the D0 detector is analyzed. Results are combined with the previously published D0 inclusive search for squarks and gluinos. No evidence of physics beyond the standard model is found and lower limits on the squark mass up to 410 GeV are derived in the framework of minimal supergravity with tan(beta)=15, A{sub 0}=-2m{sub 0} and mu<0, in the region where decays to tau leptons dominate. Gaugino masses m{sub 1/2} are excluded up to 172 GeV.
Date: May 1, 2009
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
Object Type: Article
System: The UNT Digital Library
Wind Power Across Native America: Opportunities, Challenges, and Status (Poster) (open access)

Wind Power Across Native America: Opportunities, Challenges, and Status (Poster)

Wind projects on tribal lands are differennt, and this poster outlines the ways in which these projects differ, a summary of existing and pending Native American Wind Projects (50 kW and larger), and tribal wind opportunities and issues.
Date: May 1, 2009
Creator: Jimenez, A.; Gough, R.; Flowers, L. & Taylor, R.
Object Type: Article
System: The UNT Digital Library
Higgs Boson Searches at CDF (open access)

Higgs Boson Searches at CDF

Results are presented on searches for standard model and non-standard model production of a Higgs boson in pbar-p collisions at {radical}s = 1.96 TeV with the CDF II detector at the Fermilab Tevatron. Using data corresponding to 2-3.6 1/fb of integrated luminosity, searches are performed in a number of different production and decay modes. No excess in data above that expected from backgrounds is observed; therefore, we set upper limits on the production cross section times branching fraction as a function of the Higgs boson mass.
Date: May 1, 2009
Creator: Group, Robert Craig
Object Type: Article
System: The UNT Digital Library
HIGH-TEMPERATURE ELECTROLYSIS FOR LARGE-SCALE HYDROGEN AND SYNGAS PRODUCTION FROM NUCLEAR ENERGY – SYSTEM SIMULATION AND ECONOMICS (open access)

HIGH-TEMPERATURE ELECTROLYSIS FOR LARGE-SCALE HYDROGEN AND SYNGAS PRODUCTION FROM NUCLEAR ENERGY – SYSTEM SIMULATION AND ECONOMICS

A research and development program is under way at the Idaho National Laboratory (INL) to assess the technological and scale-up issues associated with the implementation of solid-oxide electrolysis cell technology for efficient high-temperature hydrogen production from steam. This work is supported by the US Department of Energy, Office of Nuclear Energy, under the Nuclear Hydrogen Initiative. This paper will provide an overview of large-scale system modeling results and economic analyses that have been completed to date. System analysis results have been obtained using the commercial code UniSim, augmented with a custom high-temperature electrolyzer module. Economic analysis results were based on the DOE H2A analysis methodology. The process flow diagrams for the system simulations include an advanced nuclear reactor as a source of high-temperature process heat, a power cycle and a coupled steam electrolysis loop. Several reactor types and power cycles have been considered, over a range of reactor outlet temperatures. Pure steam electrolysis for hydrogen production as well as coelectrolysis for syngas production from steam/carbon dioxide mixtures have both been considered. In addition, the feasibility of coupling the high-temperature electrolysis process to biomass and coal-based synthetic fuels production has been considered. These simulations demonstrate that the addition of supplementary nuclear …
Date: May 1, 2009
Creator: O'Brien, J. E.; McKellar, M. G.; Harvego, E. A. & Stoots, C. M.
Object Type: Article
System: The UNT Digital Library
Bunch Length Monitoring at the A0 Photoinjector Using a Quasi-Optical Schottky Detector (open access)

Bunch Length Monitoring at the A0 Photoinjector Using a Quasi-Optical Schottky Detector

Noninvasive bunch duration monitoring has a crucial importance for modern accelerators intended for short wavelength FEL's, colliders and in some beam dynamics experiments. Monitoring of the bunch compression in the Emittance Exchange Experiment at the A0 Photoinjector was done using a parametric presentation of the bunch duration via Coherent Synchrotron Radiation (CSR) emitted in a dipole magnet and measured with a wideband quasi-optical Schottky Barrier Detector (SBD). The monitoring resulted in a mapping of the quadrupole parameters allowing a determination of the region of highest compression of the bunch in the sub-picosecond range. The obtained data were compared with those measured using the streak camera. A description of the technique and the results of simulations and measurements are presented and discussed in this report.
Date: May 1, 2009
Creator: Kazakevich, G.; Davidsaver, M.; Edwards, H.; Fliller, R.; Koeth, T.; Lumpkin, A. et al.
Object Type: Article
System: The UNT Digital Library
Critical Infrastructure Modeling: An Approach to Characterizing Interdependencies of Complex Networks & Control Systems (open access)

Critical Infrastructure Modeling: An Approach to Characterizing Interdependencies of Complex Networks & Control Systems

Critical infrastructure control systems face many challenges entering the 21st century, including natural disasters, cyber attacks, and terrorist attacks. Revolutionary change is required to solve many existing issues, including gaining greater situational awareness and resiliency through embedding modeling and advanced control algorithms in smart sensors and control devices instead of in a central controller. To support design, testing, and component analysis, a flexible simulation and modeling capability is needed. Researchers at Idaho National Laboratory are developing and evaluating such a capability through their CIPRsim modeling and simulation framework.
Date: May 1, 2009
Creator: Walsh, Stuart; Cherry, Shane & Roybal, Lyle
Object Type: Article
System: The UNT Digital Library
Performance Evaluation for a Modular, Scalable Passive Cooling System in Data Centers (open access)

Performance Evaluation for a Modular, Scalable Passive Cooling System in Data Centers

Scientific and enterprise data centers, IT equipment product development, and research data center laboratories typically require continuous cooling to control inlet air temperatures within recommended operating levels for the IT equipment. The consolidation and higher density aggregation of slim computing, storage and networking hardware has resulted in higher power density than what the raised-floor system design, coupled with commonly used computer rack air conditioning (CRAC) units, was originally conceived to handle. Many existing data centers and newly constructed data centers adopt CRAC units, which inherently handle heat transfer within data centers via air as the heat transfer media. This results in energy performance of the ventilation and cooling systems being less than optimal. Understanding the current trends toward higher power density in IT computing, more and more IT equipment manufacturers are designing their equipment to operate in 'conventional' data center environments, while considering provisions of alternative cooling solutions to either their equipment or supplemental cooling in rack or row systems. In the meanwhile, the trend toward higher power density resulting from current and future generations of servers has created significant opportunities for precision cooling to engineer and manufacture packaged modular and scalable systems. The modular and scalable cooling systems aim …
Date: May 1, 2009
Creator: Xu, TengFang
Object Type: Report
System: The UNT Digital Library
Integration Issues of Cells into Battery Packs for Plug-in and Hybrid Electric Vehicles: Preprint (open access)

Integration Issues of Cells into Battery Packs for Plug-in and Hybrid Electric Vehicles: Preprint

The main barriers to increased market share of hybrid electric vehicles (HEVs) and commercialization of plug-in HEVs are the cost, safety, and life of lithium ion batteries. Significant effort is being directed to address these issues for lithium ion cells. However, even the best cells may not perform as well when integrated into packs for vehicles because of the environment in which vehicles operate. This paper discusses mechanical, electrical, and thermal integration issues and vehicle interface issues that could impact the cost, life, and safety of the system. It also compares the advantages and disadvantages of using many small cells versus a few large cells and using prismatic cells versus cylindrical cells.
Date: May 1, 2009
Creator: Pesaran, A. A.; Kim, G. H. & Keyser, M.
Object Type: Article
System: The UNT Digital Library
RDI Development: Wisdom Way Solar Village, Greenfield, Massachusetts Field Test Report (open access)

RDI Development: Wisdom Way Solar Village, Greenfield, Massachusetts Field Test Report

NREL, Mountain Energy Partnership, and the Consortium of Advanced Residential Buildings conducted field tests on a house in Wisdom Way Solar Village to verify energy efficiency.
Date: May 1, 2009
Creator: Fang, X. & Hancock, E.
Object Type: Report
System: The UNT Digital Library
Water: May be the Best Near-Term Benefit and Driver of a Robust Wind Energy Future (Poster) (open access)

Water: May be the Best Near-Term Benefit and Driver of a Robust Wind Energy Future (Poster)

Water may be the most critical natural resource variable that affects the selection of generation options in the next decade. Extended drought in the western United States and more recently in the Southeast has moved water management and policy to the forefront of the energy options discussions. Recent climate change studies indicate that rising ambient temperatures could increase evapotranspiration by more than 25% to 30% in large regions of the country. Increasing demand for electricity, and especially from homegrown sources, inevitably will increase our thermal fleet, which consumes 400 to 700 gal/MWh for cooling. Recovering the vast oil shale resources in the West (one of the energy options discussed) is water intensive and threatens scarce water supplies. Irrigation for the growing corn ethanol industry requires 1,000 to 2,000 gallons of water for 1 gallon of production. Municipalities continue to grow and drive water demands and emerging constrained market prices upward. As illustrated by the 20% Wind Energy by 2030 analysis, wind offers an important mitigation opportunity: a 4-trillion-gallon water savings. This poster highlights the emerging constrained water situation in the United States and presents the case for wind energy as one of the very few means to ameliorate the emerging …
Date: May 1, 2009
Creator: Flowers, L. & Reategui, S.
Object Type: Article
System: The UNT Digital Library
A Review of Materials for Gas Turbines Firing Syngas Fuels (open access)

A Review of Materials for Gas Turbines Firing Syngas Fuels

Following the extensive development work carried out in the 1990's, gas turbine combined-cycle (GTCC) systems burning natural gas represent a reliable and efficient power generation technology widely used in many parts of the world. A critical factor was that, in order to operate at the high turbine entry temperatures required for high efficiency operation, aero-engine technology, i.e., single-crystal blades, thermal barrier coatings, and sophisticated cooling techniques had to be rapidly scaled up and introduced into these large gas turbines. The problems with reliability that resulted have been largely overcome, so that the high-efficiency GTCC power generation system is now a mature technology, capable of achieving high levels of availability. The high price of natural gas and concern about emission of greenhouse gases has focused attention on the desirability of replacing natural gas with gas derived from coal (syngas) in these gas turbine systems, since typical systems analyses indicate that IGCC plants have some potential to fulfil the requirement for a zero-emissions power generation system. In this review, the current status of materials for the critical hot gas path parts in large gas turbines is briefly considered in the context of the need to burn syngas. A critical factor is that …
Date: May 1, 2009
Creator: Gibbons, Thomas & Wright, Ian G
Object Type: Report
System: The UNT Digital Library
RF Integration into Helical Magnet for Muon 6-Dimensional Beam Cooling (open access)

RF Integration into Helical Magnet for Muon 6-Dimensional Beam Cooling

The helical cooling channel is proposed to make a quick muon beam phase space cooling in a short channel length. The challenging part of the helical cooling channel magnet design is how to integrate the RF cavity into the compact helical cooling magnet. This report shows the possibility of the integration of the system.
Date: May 1, 2009
Creator: Yonehara, K.; Kashikhin, V.; Lamm, M.; Lee, A.; Lopes, M.; Zlobin, A. et al.
Object Type: Article
System: The UNT Digital Library
The Advanced Test Reactor National Scientific User Facility Advancing Nuclear Technology (open access)

The Advanced Test Reactor National Scientific User Facility Advancing Nuclear Technology

To help ensure the long-term viability of nuclear energy through a robust and sustained research and development effort, the U.S. Department of Energy (DOE) designated the Advanced Test Reactor and associated post-irradiation examination facilities a National Scientific User Facility (ATR NSUF), allowing broader access to nuclear energy researchers. The mission of the ATR NSUF is to provide access to world-class nuclear research facilities, thereby facilitating the advancement of nuclear science and technology. The ATR NSUF seeks to create an engaged academic and industrial user community that routinely conducts reactor-based research. Cost free access to the ATR and PIE facilities is granted based on technical merit to U.S. university-led experiment teams conducting non-proprietary research. Proposals are selected via independent technical peer review and relevance to DOE mission. Extensive publication of research results is expected as a condition for access. During FY 2008, the first full year of ATR NSUF operation, five university-led experiments were awarded access to the ATR and associated post-irradiation examination facilities. The ATR NSUF has awarded four new experiments in early FY 2009, and anticipates awarding additional experiments in the fall of 2009 as the results of the second 2009 proposal call. As the ATR NSUF program mature …
Date: May 1, 2009
Creator: Allen, T. R.; Benson, J. B.; Foster, J. A.; Marshall, F. M.; Meyer, M. K. & Thelen, M. C.
Object Type: Article
System: The UNT Digital Library
The effect of resist on the transfer of line-edge roughness spatial metrics from mask to wafer (open access)

The effect of resist on the transfer of line-edge roughness spatial metrics from mask to wafer

Mask contributors to line-edge roughness (LER) have recently been shown to be an issue of concern for both the accuracy of current resist evaluation tests as well the ultimate LER requirements for the 22-nm production node. More recently, it has been shown that the power spectral density of the mask-induced roughness, is markedly different than that of intrinsic resist roughness and thus potentially serves as a mechanism for distinguishing mask effects from resist effects in experimental results. Further considering stochastic resist effects, however, demonstrates that such a test would only be viable in cases where the resist effects are completely negligible in terms of their contribution to the total LER compared to the mask effects. The results presented here lead us to the surprising conclusion that it is indeed possible for mask contributors to be the dominant source of LER while the spatial characteristics of the LER remain indistinguishable from the fractal characteristics of resist-induced LER.
Date: May 1, 2009
Creator: Naulleau, Patrick & Gallatin, Gregg
Object Type: Article
System: The UNT Digital Library
Experiments Performed in Substantiation of the Conditioning of BN-350 Spent Cesium Traps Using Lead or Lead-Bismuth Alloy Filling Technology (open access)

Experiments Performed in Substantiation of the Conditioning of BN-350 Spent Cesium Traps Using Lead or Lead-Bismuth Alloy Filling Technology

The technology of cleaning cesium radionuclides from sodium coolant at the BN-350 fast reactor was realized in the form of cesium traps of two types: stationary devices connected to the circuit that was to be cleaned and in-core devices installed into the core of reactor when it was not under operation. Carbon-graphite materials were used as sorbents to collect and concentrate radioactive cesium, accumulated in the BN-350 reactor circuits over the decades of their operation, in relatively small volume traps which provided effective radiation-safe conditions for personnel working in proximity to the coolant and equipment of the primary circuit during BN-350 decommissioning. Spent cesium traps, as products unfit for further use, represent solid radioactive wastes. The presence of chemically active sodium, potassium and cesium that are able to react violently with water results in series of problems related to their disposal in the Republic of Kazakhstan. Considering the technology of filling spent cesium traps with lead/lead-bismuth alloy as a priority one for their conditioning, evaluations for safety substantiation were implemented. A set of experiments was implemented aimed at verification of calculations performed in substantiation of the proposed technology: filling a full scale cesium trap mock-up with sodium followed by its …
Date: May 1, 2009
Creator: Romanenko, O.; Tazhibaeva, I.; Yakovlev, I.; Ivanov, A.; Wells, D.; Herrick, A. et al.
Object Type: Article
System: The UNT Digital Library
Assessment of Historic Trend in Mobility and Energy Use in India Transportation Sector Using Bottom-up Approach (open access)

Assessment of Historic Trend in Mobility and Energy Use in India Transportation Sector Using Bottom-up Approach

Transportation mobility in India has increased significantly in the past decades. From 1970 to 2000, motorized mobility (passenger-km) has risen by 888%, compared with an 88% population growth (Singh,2006). This contributed to many energy and environmental issues, and an energy strategy incorporates efficiency improvement and other measures needs to be designed. Unfortunately, existing energy data do not provide information on driving forces behind energy use and sometime show large inconsistencies. Many previous studies address only a single transportation mode such as passenger road travel; did not include comprehensive data collection or analysis has yet been done, or lack detail on energy demand by each mode and fuel mix. The current study will fill a considerable gap in current efforts, develop a data base on all transport modes including passenger air and water, and freight in order to facilitate the development of energy scenarios and assess significance of technology potential in a global climate change model. An extensive literature review and data collection has been done to establish the database with breakdown of mobility, intensity, distance, and fuel mix of all transportation modes. Energy consumption was estimated and compared with aggregated transport consumption reported in IEA India transportation energy data. Different …
Date: May 1, 2009
Creator: Zhou, Nan & McNeil, Michael A.
Object Type: Report
System: The UNT Digital Library
Are mixed explicit/implicit solvation models reliable for studying phosphate hydrolysis? A comparative study of continuum, explicit and mixed solvation models. (open access)

Are mixed explicit/implicit solvation models reliable for studying phosphate hydrolysis? A comparative study of continuum, explicit and mixed solvation models.

Phosphate hydrolysis is ubiquitous in biology. However, despite intensive research on this class of reactions, the precise nature of the reaction mechanism remains controversial. In this work, we have examined the hydrolysis of three homologous phosphate diesters. The solvation free energy was simulated by means of either an implicit solvation model (COSMO), hybrid quantum mechanical / molecular mechanical free energy perturbation (QM/MM-FEP) or a mixed solvation model in which N water molecules were explicitly included in the ab initio description of the reacting system (where N=1-3), with the remainder of the solvent being implicitly modelled as a continuum. Here, both COSMO and QM/MM-FEP reproduce Delta Gobs within an error of about 2kcal/mol. However, we demonstrate that in order to obtain any form of reliable results from a mixed model, it is essential to carefully select the explicit water molecules from short QM/MM runs that act as a model for the true infinite system. Additionally, the mixed models tend to be increasingly inaccurate the more explicit water molecules are placed into the system. Thus, our analysis indicates that this approach provides an unreliable way for modelling phosphate hydrolysis in solution.
Date: May 1, 2009
Creator: Kamerlin, Shina C. L.; Haranczyk, Maciej & Warshel, Arieh
Object Type: Article
System: The UNT Digital Library
Searches for new physics in top events at the Tevatron (open access)

Searches for new physics in top events at the Tevatron

During the past years the CDF and D0 detectors have collected large amounts of data obtaining a relatively pure sample of pair-produced top quarks and a well understood sample containing singly-produced top quarks. These samples have been used for the precise measurement of the top quark properties, and have set stringent limits on new physics in the top sample. This reports presents the latest results from the CDF and D0 collaborations on the search for new physics within the top sample using an integrated data sample of up to 3.6 fb{sup -1}.
Date: May 1, 2009
Creator: Eusebi, Ricardo; collaboration, CDF & collaboration, D0
Object Type: Article
System: The UNT Digital Library
Effect of Reacting Surface Density on the Overall Graphite Oxidation Rate (open access)

Effect of Reacting Surface Density on the Overall Graphite Oxidation Rate

Graphite oxidation in an air-ingress accident is presently a very important issue for the reactor safety of the very high temperature gas cooled-reactor (VHTR), the concept of the next generation nuclear plant (NGNP) because of its potential problems such as mechanical degradation of the supporting graphite in the lower plenum of the VHTR might lead to core collapse if the countermeasure is taken carefully. The oxidation process of graphite has known to be affected by various factors, including temperature, pressure, oxygen concentration, types of graphite, graphite shape and size, flow distribution, etc. However, our recent study reveals that the internal pore characteristics play very important roles in the overall graphite oxidation rate. One of the main issues regarding graphite oxidation is the potential core collapse problem that may occur following the degradation of graphite mechanical strength. In analyzing this phenomenon, it is very important to understand the relationship between the degree of oxidization and strength degradation. In addition, the change of oxidation rate by graphite oxidation degree characterization by burn-off (ratio of the oxidized graphite density to the original density) should be quantified because graphite strength degradation is followed by graphite density decrease, which highly affects oxidation rates and patterns. …
Date: May 1, 2009
Creator: Oh, Chang H.; Kim, Eung; Lim, Jong; Schultz, Richard & Petti, David
Object Type: Article
System: The UNT Digital Library
Search for Charged Massive Long-Lived Particles Using the D0 Detector (open access)

Search for Charged Massive Long-Lived Particles Using the D0 Detector

A search for charged massive stable particles has been performed with the D0 detector using 1.1 fb{sup -1} of data. The speed of the particle has been calculated based on the time-of-flight and position information in the muon system. The present research is limited to direct pair-production of the charged massive long-lived particles. We do not consider CMSPs that result from the cascade decays of heavier particles. In this analysis, the exact values of the model parameters of the entire supersymmetric particle mass spectrum, relevant for cascade decays, are not important. We found no evidence of the signal. 95% CL cross-section upper limits have been set on the pair-productions of the stable scaler tau lepton, the gaugino-like charginos, and the higgsino-like charginos. The upper cross section limits vary from 0.31 pb to 0.04 pb, for stau masses in the range between 60 GeV and 300 GeV. We use the nominal value of the theoretical cross section to set limits on the mass of the pair produced charginos. We exclude the pair-produced stable gaugino-like charginos with mass below 206 GeV, and higgsino-like charginos below 171 GeV, respectively. Although the present sensitivity is insufficient to test the model of the pair produced …
Date: May 1, 2009
Creator: Xie, Yunhe & U., /Brown
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Low Beam Voltage, 10 MW, L-Band Cluster Klystron (open access)

Low Beam Voltage, 10 MW, L-Band Cluster Klystron

Conceptual design of a multi-beam klystron (MBK) for possible ILC and Project X applications is presented. The chief distinction between this MBK design and existing 10-MW MBK's is the low operating voltage of 60 kV. There are at least four compelling reasons that justify development at this time of a low-voltage MBK, namely (1) no pulse transformer; (2) no oil tank for high-voltage components and for the tube socket; (3) no high-voltage cables; and (4) modulator would be a compact 60-kV IGBT switching circuit. The proposed klystron consists of four clusters containing six beams each. The tube has common input and output cavities for all 24 beams, and individual gain cavities for each cluster. A closely related optional configuration, also for a 10 MW tube, would involve four totally independent cavity clusters with four independent input cavities and four 2.5 MW output ports, all within a common magnetic circuit. This option has appeal because the output waveguides would not require a controlled atmosphere, and because it would be easier to achieve phase and amplitude stability as required in individual SC accelerator cavities.
Date: May 1, 2009
Creator: Teryaev, V.; Yakovlev, V. P.; Kazakov, S. & Hirshfield, J. L.
Object Type: Article
System: The UNT Digital Library