Aging Studies of Filled and Unfilled VCE (open access)

Aging Studies of Filled and Unfilled VCE

None
Date: October 7, 2010
Creator: Letant, S; Alviso, C; Pearson, M; Wilson, T; Chinn, S & Maxwell, R
Object Type: Report
System: The UNT Digital Library
Air Temperature in the Undulator Hall (open access)

Air Temperature in the Undulator Hall

Various analyses have been performed recently to estimate the performance of the air conditioning (HVAC) system planned for the Undulator Hall. This reports summarizes the results and provides an upgrade plan to be used if new requirements are needed in the future. The estimates predict that with the planned loads the tunnel air temperature will be well within the allowed tolerance during normal operation.
Date: December 7, 2010
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Analysis of Potential Energy Saving and CO2 Emission Reduction of Home Appliances and Commercial Equipments in China (open access)

Analysis of Potential Energy Saving and CO2 Emission Reduction of Home Appliances and Commercial Equipments in China

China is now the world's largest producer and consumer of household appliances and commercial equipment. To address the growth of electricity use of the appliances, China has implemented a series of minimum energy performance standards (MEPS) for 30 appliances, and voluntary energy efficiency label for 40 products. Further, in 2005, China started a mandatory energy information label that covers 19 products to date. However, the impact of these standard and labeling programs and their savings potential has not been evaluated on a consistent basis. This research involved modeling to estimate the energy saving and CO{sub 2} emission reduction potential of the appliances standard and labeling program for products for which standards are currently in place, or under development and those proposed for development in 2010. Two scenarios that have been developed differ primarily in the pace and stringency of MEPS development. The 'Continued Improvement Scenario' (CIS) reflects the likely pace of post-2009 MEPS revisions, and the likely improvement at each revision step considering the technical limitation of the technology. The 'Best Practice Scenario' (BPS) examined the potential of an achievement of international best practice MEPS in 2014. This paper concludes that under the 'CIS' of regularly scheduled MEPS revisions to …
Date: June 7, 2010
Creator: Zhou, Nan; Fridley, David; McNeill, Michael; Zheng, Nina; Letschert, Virginie; Ke, Jing et al.
Object Type: Article
System: The UNT Digital Library
Application of Adaptive Beamforming to Signal Observations at the Mt. Meron Array, Israel (open access)

Application of Adaptive Beamforming to Signal Observations at the Mt. Meron Array, Israel

None
Date: June 7, 2010
Creator: Harris, D B
Object Type: Report
System: The UNT Digital Library
Assessment of Building Energy-Saving Policies and Programs in China During the 11th Five Year Plan (open access)

Assessment of Building Energy-Saving Policies and Programs in China During the 11th Five Year Plan

China's 11th Five-Year Plan (FYP) sets an ambitious target to reduce the energy intensity per unit of gross domestic product (GDP) by 20% from 2005 to 2010 (NDRC, 2006). In the building sector, the primary energy-saving target allocated during the 11 FYP period is 100 Mtce. Savings are expected to be achieved through the strengthening of enforcement of building energy efficiency codes, existing building retrofits and heat supply system reform, followed by energy management of government office buildings and large scale public buildings, adoption of renewable energy sources. To date, China has reported that it achieved the half of the 20% intensity reduction target by the end of 2008, however, little has been made clear on the status and the impact of the building programs. There has also been lack of description on methodology for calculating the savings and baseline definition, and no total savings that have been officially reported to date. This paper intend to provide both quantitative and qualitative assessment of the key policies and programs in building sector that China has instituted in its quest to fulfill the national goal. Overall, this paper concludes that the largest improvement for building energy efficiency were achieved in new buildings; …
Date: June 7, 2010
Creator: Zhou, Nan; McNeil, Michael & Levine, Mark
Object Type: Article
System: The UNT Digital Library
A Bayesian Approach to Multi-Sensor Track Correlation (open access)

A Bayesian Approach to Multi-Sensor Track Correlation

None
Date: September 7, 2010
Creator: Horsley, M
Object Type: Article
System: The UNT Digital Library
Boron-Lined Multichamber and Conventional Neutron Proportional Counter Tests (open access)

Boron-Lined Multichamber and Conventional Neutron Proportional Counter Tests

Radiation portal monitors used for interdiction of illicit materials at borders include highly sensitive neutron detection systems. The main reason for having neutron detection capability is to detect fission neutrons from plutonium. The currently deployed radiation portal monitors (RPMs) from Ludlum and Science Applications International Corporation (SAIC) use neutron detectors based upon 3He-filled gas proportional counters, which are the most common large neutron detector. There is a declining supply of 3He in the world, and thus, methods to reduce the use of this gas in RPMs with minimal changes to the current system designs and sensitivity to cargo-borne neutrons are being investigated. Four technologies have been identified as being currently commercially available, potential alternative neutron detectors to replace the use of 3He in RPMs. These technologies are: 1) Boron trifluoride (BF3)-filled proportional counters, 2) Boron-lined proportional counters, 3) Lithium-loaded glass fibers, and 4) Coated non-scintillating plastic fibers. In addition, a few other companies have detector technologies that might be competitive in the near term as an alternative technology. Reported here are the results of tests of a boron-lined, multichamber proportional counter manufactured by LND, Inc. Also reported are results obtained with an earlier design of conventional, boron-lined, proportional counters from …
Date: September 7, 2010
Creator: Woodring, Mitchell L.; Ely, James H.; Kouzes, Richard T. & Stromswold, David C.
Object Type: Report
System: The UNT Digital Library
Boron-Lined Multitube Neutron Proportional Counter Test (open access)

Boron-Lined Multitube Neutron Proportional Counter Test

Radiation portal monitors used for interdiction of illicit materials at borders include highly sensitive neutron detection systems. The main reason for having neutron detection capability is to detect fission neutrons from plutonium. The currently deployed radiation portal monitors (RPMs) from Ludlum and Science Applications International Corporation (SAIC) use neutron detectors based upon 3He-filled gas proportional counters, which are the most common large neutron detector. There is a declining supply of 3He in the world, and thus, methods to reduce the use of this gas in RPMs with minimal changes to the current system designs and sensitivity to cargo-borne neutrons are being investigated. Four technologies have been identified as being currently commercially available, potential alternative neutron detectors to replace the use of 3He in RPMs. These technologies are: 1) Boron trifluoride (BF3)-filled proportional counters, 2) Boron-lined proportional counters, 3) Lithium-loaded glass fibers, and 4) Coated non-scintillating plastic fibers. In addition, a few other companies have detector technologies that might be competitive in the near term as an alternative technology. Reported here are the results of tests of a boron-lined, “multitube” proportional counter manufactured by Centronic Ltd. (Surry, U.K. and Houston, TX). This testing measured the required performance for neutron detection efficiency …
Date: September 7, 2010
Creator: Woodring, Mitchell L.; Ely, James H.; Kouzes, Richard T. & Stromswold, David C.
Object Type: Report
System: The UNT Digital Library
Boron-Lined Neutron Detector Measurements (open access)

Boron-Lined Neutron Detector Measurements

PNNL-18938 Revision Radiation portal monitors used for interdiction of illicit materials at borders include highly sensitive neutron detection systems. The main reason for having neutron detection capability is to detect fission neutrons from plutonium. The currently deployed radiation portal monitors (RPMs) from Ludlum and Science Applications International Corporation (SAIC) use neutron detectors based upon 3He-filled gas proportional counters, which are the most common large neutron detector. There is a declining supply of 3He in the world, and thus, methods to reduce the use of this gas in RPMs with minimal changes to the current system designs and sensitivity to cargo-borne neutrons are being investigated. Four technologies have been identified as being currently commercially available, potential alternative neutron detectors to replace the use of 3He in RPMs. Reported here are the results of tests of a newly designed boron-lined proportional counter option. This testing measured the neutron detection efficiency and gamma ray rejection capabilities of two successive prototypes of a system manufactured by GE Reuter Stokes.
Date: March 7, 2010
Creator: Lintereur, Azaree T.; Kouzes, Richard T.; Ely, James H.; Erikson, Luke E.; Siciliano, Edward R. & Woodring, Mitchell L.
Object Type: Report
System: The UNT Digital Library
Boron-Lined Straw-Tube Neutron Detector Test (open access)

Boron-Lined Straw-Tube Neutron Detector Test

Radiation portal monitors used for interdiction of illicit materials at borders include highly sensitive neutron detection systems. The main reason for having neutron detection capability is to detect fission neutrons from plutonium. The currently deployed radiation portal monitors (RPMs) from Ludlum and Science Applications International Corporation (SAIC) use neutron detectors based upon 3He-filled gas proportional counters, which are the most common large neutron detector. There is a declining supply of 3He in the world, and thus, methods to reduce the use of this gas in RPMs with minimal changes to the current system designs and sensitivity to cargo-borne neutrons are being investigated. Four technologies have been identified as being currently commercially available, potential alternative neutron detectors to replace the use of 3He in RPMs. Reported here are the results of tests of a boron-lined proportional counter design variation. In the testing described here, the neutron detection efficiency and gamma ray rejection capabilities of a system manufactured by Proportional Technologies, Inc, was tested.
Date: August 7, 2010
Creator: Kouzes, Richard T.; Ely, James H. & Stromswold, David C.
Object Type: Report
System: The UNT Digital Library
Breast Cancer Cells in Three-dimensional Culture Display an Enhanced Radioresponse after Coordinate Targeting of Integrin ?5?1 and Fibronectin (open access)

Breast Cancer Cells in Three-dimensional Culture Display an Enhanced Radioresponse after Coordinate Targeting of Integrin ?5?1 and Fibronectin

Tactics to selectively enhance cancer radioresponse are of great interest. Cancer cells actively elaborate and remodel their extracellular matrix (ECM) to aid in survival and progression. Previous work has shown that {beta}1-integrin inhibitory antibodies can enhance the growth-inhibitory and apoptotic responses of human breast cancer cell lines to ionizing radiation, either when cells are cultured in three-dimensional laminin-rich ECM (3D lrECM) or grown as xenografts in mice. Here, we show that a specific {alpha} heterodimer of {beta}1-integrin preferentially mediates a prosurvival signal in human breast cancer cells that can be specifically targeted for therapy. 3D lrECM culture conditions were used to compare {alpha}-integrin heterodimer expression in malignant and nonmalignant cell lines. Under these conditions, we found that expression of {alpha}5{beta}1-integrin was upregulated in malignant cells compared with nonmalignant breast cells. Similarly, we found that normal and oncofetal splice variants of fibronectin, the primary ECM ligand of {alpha}5{beta}1-integrin, were also strikingly upregulated in malignant cell lines compared with nonmalignant acini. Cell treatment with a peptide that disrupts the interactions of {alpha}5{beta}1-integrin with fibronectin promoted apoptosis in malignant cells and further heightened the apoptotic effects of radiation. In support of these results, an analysis of gene expression array data from breast cancer …
Date: April 7, 2010
Creator: Nam, Jin-Min; Onodera, Yasuhito; Bissell, Mina J & Park, Catherine C
Object Type: Article
System: The UNT Digital Library
Carbide-Derived Carbons with Tunable Porosity Optimized for Hydrogen Storage (open access)

Carbide-Derived Carbons with Tunable Porosity Optimized for Hydrogen Storage

On-board hydrogen storage is a key requirement for fuel cell-powered cars and trucks. Porous carbon-based materials can in principle adsorb more hydrogen per unit weight at room temperature than liquid hydrogen at -176 oC. Achieving this goal requires interconnected pores with very high internal surface area, and binding energies between hydrogen and carbon significantly enhanced relative to H2 on graphite. In this project a systematic study of carbide-derived carbons, a novel form of porous carbon, was carried out to discover a high-performance hydrogen sorption material to meet the goal. In the event we were unable to improve on the state of the art in terms of stored hydrogen per unit weight, having encountered the same fundamental limit of all porous carbons: the very weak interaction between H2 and the carbon surface. On the other hand we did discover several strategies to improve storage capacity on a volume basis, which should be applicable to other forms of porous carbon. Further discoveries with potentially broader impacts include • Proof that storage performance is not directly related to pore surface area, as had been previously claimed. Small pores (< 1.5 nm) are much more effective in storing hydrogen than larger ones, such that …
Date: January 7, 2010
Creator: Fisher, John E.; Gogotsi, Yury & Yildirim, Taner
Object Type: Report
System: The UNT Digital Library
Chemical Agent Incident-Response and Recovery Decision Process (open access)

Chemical Agent Incident-Response and Recovery Decision Process

None
Date: September 7, 2010
Creator: Raber, E; Greenwalt, R; Hibbard, W; MacQueen, D; Mancieri, S; Reutter, D et al.
Object Type: Report
System: The UNT Digital Library
China Energy Efficiency Round Robin Testing Results for Room Air Conditioners (open access)

China Energy Efficiency Round Robin Testing Results for Room Air Conditioners

In recent years China's energy consumption has increased rapidly. The problem of high energy consumption intensity and low energy utilization efficiency is serious, and the contradiction between economic development and energy and environmental resources has become increasingly acute, making energy conservation and consumption reduction an important society-wide concern. At the same time, global climate change has and will continue to have profound impacts on human survival and development, and is another major challenge to all countries. In order to accelerate China's energy conservation and emission reduction work, the National Leading Group to Address Climate Change, Energy Conservation and Emission Reduction was founded with Premier Wen Jiabao as the head, and the 'Comprehensive Work Program of Energy Conservation and Emission Reduction' and 'China's National Program of Addressing Climate Change' were issued, under which China's energy conservation and emission reduction work has been fully deployed. Efforts to promote energy efficiency have been further strengthened in all levels of government, and various policies and measures have progressively been issued and implemented. In addition, based on China's experience with implementing energy-saving priority strategies over the past 20+ years, our government established a goal of a 20% decrease in energy consumption per unit GDP in …
Date: June 7, 2010
Creator: Zhou, Nan; Fridley, David; Zheng, Nina & Pierrot, Andre
Object Type: Report
System: The UNT Digital Library
Cleanroom Energy Efficiency: Metrics and Benchmarks (open access)

Cleanroom Energy Efficiency: Metrics and Benchmarks

Cleanrooms are among the most energy-intensive types of facilities. This is primarily due to the cleanliness requirements that result in high airflow rates and system static pressures, as well as process requirements that result in high cooling loads. Various studies have shown that there is a wide range of cleanroom energy efficiencies and that facility managers may not be aware of how energy efficient their cleanroom facility can be relative to other cleanroom facilities with the same cleanliness requirements. Metrics and benchmarks are an effective way to compare one facility to another and to track the performance of a given facility over time. This article presents the key metrics and benchmarks that facility managers can use to assess, track, and manage their cleanroom energy efficiency or to set energy efficiency targets for new construction. These include system-level metrics such as air change rates, air handling W/cfm, and filter pressure drops. Operational data are presented from over 20 different cleanrooms that were benchmarked with these metrics and that are part of the cleanroom benchmark dataset maintained by Lawrence Berkeley National Laboratory (LBNL). Overall production efficiency metrics for cleanrooms in 28 semiconductor manufacturing facilities in the United States and recorded in the …
Date: July 7, 2010
Creator: Initiative, International SEMATECH Manufacturing; Mathew, Paul A.; Tschudi, William; Sartor, Dale & Beasley, James
Object Type: Article
System: The UNT Digital Library
Compact, Intelligent, Digitally Controlled IGBT Gate Drivers for a PEBB-Based ILC Marx Modulator (open access)

Compact, Intelligent, Digitally Controlled IGBT Gate Drivers for a PEBB-Based ILC Marx Modulator

SLAC National Accelerator Laboratory has built and is currently operating a first generation prototype Marx klystron modulator to meet ILC specifications. Under development is a second generation prototype, aimed at improving overall performance, serviceability, and manufacturability as compared to its predecessor. It is designed around 32 cells, each operating at 3.75 kV and correcting for its own capacitor droop. Due to the uniqueness of this application, high voltage gate drivers needed to be developed for the main 6.5 kV and droop correction 1.7 kV IGBTs. The gate driver provides vital functions such as protection of the IGBT from over-voltage and over-current, detection of gate-emitter open and short circuit conditions, and monitoring of IGBT degradation (based on collector-emitter saturation voltage). Gate drive control, diagnostic processing capabilities, and communication are digitally implemented using an FPGA. This paper details the design of the gate driver circuitry, component selection, and construction layout. In addition, experimental results are included to illustrate the effectiveness of the protection circuit.
Date: June 7, 2010
Creator: Nguyen, M. N.; Burkhart, C.; Olsen, J. J. & Macken, K.
Object Type: Article
System: The UNT Digital Library
Comparison of Poloidal Velocity Meassurements to Neoclassical Theory on the National Spherical Torus Experiment (open access)

Comparison of Poloidal Velocity Meassurements to Neoclassical Theory on the National Spherical Torus Experiment

Knowledge of poloidal velocity is necessary for the determination of the radial electric field, Er, which along with its gradient is linked to turbulence suppression and transport barrier formation. Recent measurements of poloidal flow on conventional tokamaks have been reported to be an order of magnitude larger than expected from neoclassical theory. In contrast, recent poloidal velocity measurements on the NSTX spherical torus [S. M. Kaye et al., Phys. Plasmas 8, 1977 (2001)] are near or below neoclassical estimates. A novel charge exchange recombination spectroscopy diagnostic is used, which features active and passive sets of up/down symmetric views to produce line-integrated poloidal velocity measurements that do not need atomic physics corrections. Local profiles are obtained with an inversion. Poloidal velocity measurements are compared with neoclassical values computed with the codes NCLASS [W. A. Houlberg et al., Phys. Plasmas 4, 3230 (1997)] and GTC-Neo [W. X. Wang, et al., Phys. Plasmas 13, 082501 (2006)], which has been updated to handle impurities. __________________________________________________
Date: April 7, 2010
Creator: Bell, R. E.; Kaye, S. M.; Kolesnikov, R. A.; LeBlance, B. P.; Rewolldt, G. & Wang, W. X.
Object Type: Report
System: The UNT Digital Library
Cryogenic Adsorption of Hydrogen Isotopes Over Nano-Structured Materials (open access)

Cryogenic Adsorption of Hydrogen Isotopes Over Nano-Structured Materials

Porous materials such as zeolites, activated carbon, silica gels, alumina and a number of industrial catalysts are compared and ranked for hydrogen and deuterium adsorption at liquid nitrogen temperature. All samples show higher D{sub 2} adsorption than that of H{sub 2}, in which a HY sample has the greatest isotopic effect while 13X has the highest hydrogen uptake capacity. Material's moisture content has significant impact to its hydrogen uptake. A material without adequate drying could result in complete loss of its adsorption capacity. Even though some materials present higher H{sub 2} adsorption capacity at full pressure, their adsorption at low vapor pressure may not be as good as others. Adsorption capacity in a dynamic system is much less than in a static system. A sharp desorption is also expected in case of temperature upset.
Date: October 7, 2010
Creator: Xiao, S. & Heung, L.
Object Type: Article
System: The UNT Digital Library
Dense Heterogeneous Continuum Model of Two-Phase Explosion Fields (open access)

Dense Heterogeneous Continuum Model of Two-Phase Explosion Fields

A heterogeneous continuum model is proposed to describe the dispersion of a dense Aluminum particle cloud in an explosion. Let {alpha}{sub 1} denote the volume fraction occupied by the gas and {alpha}{sub 2} the fraction occupied by the solid, satisfying the volume conservation relation: {alpha}{sub 1} + {alpha}{sub 2} = 1. When the particle phase occupies a non-negligible volume fraction (i.e., {alpha}{sub 2} &gt; 0), additional terms, proportional to {alpha}{sub 2}, appear in the conservation laws for two-phase flows. These include: (i) a particle pressure (due to particle collisions), (ii) a corresponding sound speed (which produces real eigenvalues for the particle phase system), (iii) an Archimedes force induced on the particle phase (by the gas pressure gradient), and (iv) multi-particle drag effects (which enhance the momentum coupling between phases). These effects modify the accelerations and energy distributions in the phases; we call this the Dense Heterogeneous Continuum Model. A characteristics analysis of the Model equations indicates that the system is hyperbolic with real eigenvalues for the gas phase: {l_brace}v{sub 1}, v{sub 1} {+-} {alpha}{sub 1}{r_brace} and for the 'particle gas' phase: {l_brace}v{sub 2}, v{sub 2} {+-}{alpha}{sub 2}{r_brace} and the particles: {l_brace}v{sub 2}{r_brace}, where v{sub i} and {alpha}{sub i} denote the …
Date: April 7, 2010
Creator: Kuhl, A L & Bell, J B
Object Type: Article
System: The UNT Digital Library
The Dependence of the Oxidation Enhancement of InP(100) Surface on the Coverage of the Adsorbed Cs (open access)

The Dependence of the Oxidation Enhancement of InP(100) Surface on the Coverage of the Adsorbed Cs

We report the oxidation of the InP(100) surface promoted by adsorbed Cs by synchrotron radiation photoemission. Oxygen exposure causes reduction of the charge transferred to the InP substrate from Cs and the growth of indium oxide and phosphorous oxide. The oxide growth displays a clear dependence on the Cs coverage. The oxidation of phosphorous is negligible up to 1000 L of O{sub 2} exposure when the Cs coverage is less than half a monolayer (ML), but the formation of the second half monolayer of Cs greatly accelerates the oxidation. This different enhancement of the InP oxidation by the first and the second half monolayer of Cs is due to the double layer structure of the adsorbed Cs atoms, and consequently the higher 6s electron density in the Cs atoms when Cs coverage is larger than 0.5 ML.
Date: June 7, 2010
Creator: Sun, Yun
Object Type: Article
System: The UNT Digital Library
Designing and Operating for Safeguards: Lessons Learned From the Rokkasho Reprocessing Plant (RRP) (open access)

Designing and Operating for Safeguards: Lessons Learned From the Rokkasho Reprocessing Plant (RRP)

This paper will address the lessons learned during the implementation of International Atomic Energy Agency (IAEA) safeguards at the Rokkasho Reprocessing Plant (RRP) which are relevant to the issue of ‘safeguards by design’. However, those lessons are a result of a cumulative history of international safeguards experiences starting with the West Valley reprocessing plant in 1969, continuing with the Barnwell plant, and then with the implementation of international safeguards at WAK in Germany and TRP in Japan. The design and implementation of safeguards at RRP in Japan is the latest and most challenging that the IAEA has faced. This paper will discuss the work leading up to the development of a safeguards approach, the design and operating features that were introduced to improve or aid in implementing the safeguards approach, and the resulting recommendations for future facilities. It will provide an overview of how ‘safeguardability’ was introduced into RRP.
Date: August 7, 2010
Creator: Johnson, Shirley J. & Ehinger, Michael
Object Type: Report
System: The UNT Digital Library
Development of a Hydrogen Isotope Extrapolation  Curve for Platinum Catylized Zeolite (open access)

Development of a Hydrogen Isotope Extrapolation Curve for Platinum Catylized Zeolite

Experiments were conducted in 2003 and 2004 with protium and deuterium to demonstrate the hydrogen exchange properties of various catalyzed zeolites for tritium stripping purposes. A column was loaded with the experimental material and purged with either H{sub 2} or D{sub 2} as shown in Figure 1 and the effluent monitored with a Prisma Quadrupole. The purge gas was switched when the column outlet concentrations reached &gt;95% of the purge isotope. Outlet concentrations were calculated as the sum of the purge isotope in the elemental form plus the purge isotope in the oxide form (the purge stream was humidified as it passed through the column) divided by the total hydrogen isotopes in the effluent. 1.5 wt.% Pt on CBV 780 zeolite, manufactured by Zeolist International, had the best exchange characteristics, high capacity and fast kinetics, of the materials tested. This memorandum describes an approach to extrapolate previously unpublished hydrogen for deuterium exchange data collected earlier on 1.5 wt.% Pt on CBV 780 to lower concentrations for potential engineering applications.
Date: July 7, 2010
Creator: Staack, G.
Object Type: Report
System: The UNT Digital Library
Development of Controlled Pitch Nano Arrays for Application in Nano Scale Based Proportional Counters (open access)

Development of Controlled Pitch Nano Arrays for Application in Nano Scale Based Proportional Counters

Proportional counters (PCs) are a type of gas-filled radiation detection device capable of distinguishing between a wide range of radiation types and energies. In this application, however, these devices are limited by high power consumption and high bias potentials required to operate in the proportional detection regime. Previous work performed with a single carbon nanotube (CNT) anode has shown that nanoscale-based PCs can operate at bias potentials of 10V rather than the 1000V range required for PCs. ''Proof of concept'' experiments with a single CNT as the anode exhibit a small detection volume and consequently required long count times (24 hrs). To make this a practical detector technology (i.e., decrease the count time), the effective detection volume has to be increased. Experimental data and electric field modeling show that if the pitch (spacing between individual nanotubes) of the arrays is too small, the electric field of the individual nanostructure will collapse and the nanoscale array will behaved as a single macro-scale field with the associated high bias potential required to reach the proportional region. Electric-field modeling of the affect of nanostructure pitch on the electric field distribution of these arrays predicted that a pitch of about two-and-a-times the height of …
Date: June 7, 2010
Creator: Sexton, L.; Serkiz, S. & Siegfried, M.
Object Type: Article
System: The UNT Digital Library
Development Status of The ILC Marx Modulator (open access)

Development Status of The ILC Marx Modulator

The ILC Marx Modulator is under development as a lower cost alternative to the 'Baseline Conceptual Design' (BCD) klystron modulator. Construction of a prototype Marx is complete and testing is underway at SLAC. The Marx employs solid state elements, IGBTs and diodes, to control the charge, discharge and isolation of the modules. The prototype is based on a stack of sixteen modules, each initially charged to {approx}11 kV, which are arranged in a Marx topology. Initially, eleven modules combine to produce the 120 kV output pulse. The remaining modules are switched in after appropriate delays to compensate for the voltage droop that results from the discharge of the energy storage capacitors. Additional elements will further regulate the output voltage to {+-}0.5%. The Marx presents several advantages over the conventional klystron modulator designs. It is physically smaller; there is no pulse transformer (quite massive at these parameters) and the energy storage capacitor bank is quite small, owing to the active droop compensation. It is oil-free; voltage hold-off is achieved using air insulation. It is air cooled; the secondary air-water heat exchanger is physically isolated from the electronic components. This paper outlines the current developmental status of the prototype Marx. It presents …
Date: June 7, 2010
Creator: Nguyen, M.; Beukers, T.; Burkhart, C.; Larsen, R.; Olsen, J. & Tang, T.
Object Type: Article
System: The UNT Digital Library