Resource Type

0.25mm-Thick CCD Packaging for the Dark Energy Survey Camera Array (open access)

0.25mm-Thick CCD Packaging for the Dark Energy Survey Camera Array

Abstract: The Dark Energy Survey Camera focal plane array will consist of 62 2k x 4k CCDs with a pixel size of 15 microns and a silicon thickness of 250 microns for use at wavelengths between 400 and 1000 nm. Bare CCD die will be received from the Lawrence Berkeley National Laboratory (LBNL). At the Fermi National Accelerator Laboratory, the bare die will be packaged into a custom back-side-illuminated module design. Cold probe data from LBNL will be used to select the CCDs to be packaged. The module design utilizes an aluminum nitride readout board and spacer and an Invar foot. A module flatness of 3 microns over small (1 sqcm) areas and less than 10 microns over neighboring areas on a CCD are required for uniform images over the focal plane. A confocal chromatic inspection system is being developed to precisely measure flatness over a grid up to 300 x 300 mm. This system will be utilized to inspect not only room-temperature modules, but also cold individual modules and partial arrays through flat dewar windows.
Date: 2006-06~
Creator: Derylo, Greg; Diehl, H. Thomas & Estrada, Juan
System: The UNT Digital Library
A 1 MEGAWATT POLYPHASE BOOST CONVERTER-MODULATOR FOR KLYSTRON PULSE APPLICATION (open access)

A 1 MEGAWATT POLYPHASE BOOST CONVERTER-MODULATOR FOR KLYSTRON PULSE APPLICATION

This paper describes electrical design criteria and first operational results a 140 kV, 1 MW average, 11 MW peak, zero-voltage-switching 20 kHz polyphase bridge, boost converter/modulator for klystron pulse application. The DC-DC converter derives the buss voltages from a standard 13.8 kV to 2300 Y substation cast-core transformer. Energy storage and filtering is provided by self-clearing metallized hazy polypropylene traction capacitors. Three ''H-Bridge'' Insulated Gate Bipolar Transistor (IGBT) switching networks are used to generate the polyphase 20 kHz transformer primary drive waveforms. The 20 kHz drive waveforms are chirped the appropriate duration to generate the desired klystron pulse width. PWM (pulse width modulation) of the individual 20 kHz pulses is utilized to provide regulated output waveforms with adaptive feedforward and feedback techniques. The boost transformer design utilizes amorphous nanocrystalline material that provides the required low core loss at design flux levels and switching frequencies. Resonant shunt-peaking is used on the transformer secondary to boost output voltage and resonate transformer leakage inductance. With the appropriate transformer leakage inductance and peaking capacitance, zero-voltage-switching of the IGBT's is attained, minimizing switching losses. A review of these design parameters and the first results of the performance characteristics will be presented.
Date: June 1, 2001
Creator: Reass, W. A.; Doss, J. D. & Gribble, R. F.
System: The UNT Digital Library
1 nA beam position monitoring system (open access)

1 nA beam position monitoring system

A system has been developed at Jefferson Lab for measuring transverse position of very low current beams delivered to the Experimental Hall B of the Continuous Electron Beam Accelerator Facility (CEBAF). At the heart of the system is a position sensitive cavity operating at 1497 MHz. The cavity utilizes a unique design which achieves a high sensitivity to beam position at a relatively low cavity Q. The cavity output RF signal is processed using a down-converter and a commercial lock-in amplifier operating at 100 kHz. The system interfaces with a VME based EPICS control system using the IEEE, 488 bus. The main features of the system are simple and robust design, and wide dynamic range capable of handling beam currents from 1 nA to 1000 nA with an expected resolution better than 100 {mu}m. This paper outlines the design of the system.
Date: June 1, 1997
Creator: Ursic, R.; Flood, R. & Piller, C.
System: The UNT Digital Library
A 1- to 5-MW, RCS-based, short-pulse spallation neutron source (open access)

A 1- to 5-MW, RCS-based, short-pulse spallation neutron source

Two accelerator configurations, the linac/compressor ring scheme and the linac/RCS scheme, are commonly used to provide the proton beam power for a short-pulse spallation neutron source. In one configuration, a full-power linac provides the beam power and a compressor ring shortens the pulse length from 1-ms down to 1 {micro}s. In the other, rapid cycling synchrotrons (RCSs) provide the beam power and also shorten the pulse length. A feasibility study of a staged approach to a 5-MW proton source utilizing RCS technology, allowing intermediate operation at 1 MW, was performed at ANL and is presented in this paper. This study is complementary to a study in progress at ORNL based on a linac and an accumulator ring. The 1-MW facility consists of a 400-MeV injector linac that delivers 0.5-mA time-averaged current, a synchrotron that accelerates the beam to 2 GeV at a 30-Hz rate, and two neutron-generating target stations. In the second phase, the 2-GeV beam is accelerated to 10 GeV by a larger RCS, increasing the facility beam power to 5 MW.
Date: June 1997
Creator: Cho, Y.; Chae, Y.-C. & Crosbie, E.
System: The UNT Digital Library
2-D or not 2-D, that is the question: A Northern California test (open access)

2-D or not 2-D, that is the question: A Northern California test

Reliable estimates of the seismic source spectrum are necessary for accurate magnitude, yield, and energy estimation. In particular, how seismic radiated energy scales with increasing earthquake size has been the focus of recent debate within the community and has direct implications on earthquake source physics studies as well as hazard mitigation. The 1-D coda methodology of Mayeda et al. has provided the lowest variance estimate of the source spectrum when compared against traditional approaches that use direct S-waves, thus making it ideal for networks that have sparse station distribution. The 1-D coda methodology has been mostly confined to regions of approximately uniform complexity. For larger, more geophysically complicated regions, 2-D path corrections may be required. The complicated tectonics of the northern California region coupled with high quality broadband seismic data provides for an ideal ''apples-to-apples'' test of 1-D and 2-D path assumptions on direct waves and their coda. Using the same station and event distribution, we compared 1-D and 2-D path corrections and observed the following results: (1) 1-D coda results reduced the amplitude variance relative to direct S-waves by roughly a factor of 8 (800%); (2) Applying a 2-D correction to the coda resulted in up to 40% variance …
Date: June 6, 2005
Creator: Mayeda, K; Malagnini, L; Phillips, W S; Walter, W R & Dreger, D
System: The UNT Digital Library
A 2-D Self-Consistent DSMC Model for Chemically Reacting Low Pressure Plasma Reactors (open access)

A 2-D Self-Consistent DSMC Model for Chemically Reacting Low Pressure Plasma Reactors

This paper will focus on the methodology of using a 2D plasma Direct Simulation Monte Carlo technique to simulate the species transport in an inductively coupled, low pressure, chemically reacting plasma system. The pressure in these systems is typically less than 20 mtorr with plasma densities of approximately 10{sup 17} {number_sign}/m{sup 3} and an ionization level of only 0.1%. This low ionization level tightly couples the neutral, ion, and electron chemistries and interactions in a system where the flow is subsonic. We present our strategy and compare simulation results to experimental data for Cl{sub 2} in a Gaseous Electronics Conference (GEC) reference cell modified with an inductive coil.
Date: June 17, 1999
Creator: Bartel, Timothy J.; Economou, Demetre & Johannes, Justine E.
System: The UNT Digital Library
A 2-Megawatt load for testing high voltage dc power supplies (open access)

A 2-Megawatt load for testing high voltage dc power supplies

A high power water-cooled resistive load, capable of dissipating 2 Megawatts at 95 kilovolts is being designed and built. The load utilizes wirewound resistor elements suspended inside insulating tubing contained within a pressure vessel which is supplied a continuous flow of deionized water for coolant. A sub-system of the load is composed of non-inductive resistor elements in an oil tank. Power tests conducted on various resistor types indicate that dissipation levels as high as 22 times the rated dissipation in air can be achieved when the resistors are placed in a turbulent water flow of at least 15 gallons per minute. Using this data, the load w.as designed using 100 resistor elements in a series arrangement A single-wall 316 stainless steel pressure vessel with flanged torispherical heads is built to contain the resistor assembly and deionized water. The resistors are suspended within G-11 tubing which span the cylindrical length of the vessel. These tubes are supported by G-10 baffles which also increase convection from the tubes by promoting turbulence within the surrounding water.
Date: June 1, 1993
Creator: Horan, D.; Kustom, R.; Ferguson, M. & Primdahl, K.
System: The UNT Digital Library
A 2-MV multi-beam injector for heavy ion fusion (open access)

A 2-MV multi-beam injector for heavy ion fusion

Construction of a sixteen beam (0.5 A per beam) injector for use in scaled heavy ion fusion experiments is underway at LBL. The machine was designed and partially constructed at LANL. The injector is designed to use carbon arc sources which will provide 25 mA/cm/sup 2/ of extractable current density. The plasma from the arcs is confined electrostatically from drifting into the ion gun before firing the extraction pulse. The acceleration column consists of a set of aperture lenses which both transport the beam and attenuate backstreaming electrons. The acceleration column is mounted inside a 28-inch diameter brazed alumina insulating module. The high voltage for the injector is provided by an inductively loaded and graded Marx generator which resides inside a pressure vessel filled with a 65 psig mixture of 30/percent/ SF/sub 6/ and 70/percent/ N/sub 2/. Data is presented showing the performance of single and multiple carbon arc sources. Measurements show that adequate current density is available. Emittance measurements and efforts to improve emittance and reproducibility are shown. Tests with a 5-tray section of the full 18 tray generator are described showing the evolution of the generator design. 5 refs., 3 figs.
Date: June 1, 1988
Creator: Rutkowski, H. L.; Faltens, A.; Vanecek, D.; Pike, C.; Humphries, S., Jr. & Meyer, E. A.
System: The UNT Digital Library
2 MW upgrade of the Fermilab Main Injector (open access)

2 MW upgrade of the Fermilab Main Injector

In January 2002, the Fermilab Director initiated a design study for a high average power, modest energy proton facility. An intensity upgrade to Fermilab's 120-GeV Main Injector (MI) represents an attractive concept for such a facility, which would leverage existing beam lines and experimental areas and would greatly enhance physics opportunities at Fermilab and in the U.S. With a Proton Driver replacing the present Booster, the beam intensity of the MI is expected to be increased by a factor of five. Accompanied by a shorter cycle, the beam power would reach 2 MW. This would make the MI a more powerful machine than the SNS or the J-PARC. Moreover, the high beam energy (120 GeV) and tunable energy range (8-120 GeV) would make it a unique high power proton facility. The upgrade study has been completed and published. This paper gives a summary report.
Date: June 4, 2003
Creator: Chou, Weiren
System: The UNT Digital Library
3.9 GHz superconducting accelerating 9-cell cavity vertical test results (open access)

3.9 GHz superconducting accelerating 9-cell cavity vertical test results

The 3rd harmonic 3.9GHz accelerating cavity was proposed to improve the beam performance of the FLASH (TTF/DESY) facility [1]. In the frame of a collaborative agreement, Fermilab will provide DESY with a cryomodule containing a string of four cavities. In addition, a second cryomodule with one cavity will be fabricated for installation in the Fermilab photo-injector, which will be upgraded for the ILC accelerator test facility. The first 9-cell Nb cavities were tested in a vertical setup and they didn't reach the designed accelerating gradient [2]. The main problem was a multipactor in the HOM couplers, which lead to overheating and quenching of the HOM couplers. New HOM couplers with improved design are integrated in the next 9-cell cavities. In this paper we present all results of the vertical tests.
Date: June 1, 2007
Creator: Khabiboulline, Timergali; Cooper, Charles; Dhanaraj, Nandhini; Edwards, Helen; Foley, Mike; Harms, Elvin et al.
System: The UNT Digital Library
3.9 GHz superconducting accelerating 9-cell cavity vertical test results (open access)

3.9 GHz superconducting accelerating 9-cell cavity vertical test results

None
Date: June 1, 2007
Creator: Khabiboulline, Timergali; Cooper, Charles; Dhanaraj, Nandhini; Edwards, Helen; Foley, Mike; Harms, Elvin et al.
System: The UNT Digital Library
3-D hybrid PIC code to model the tilt mode in FRCs (open access)

3-D hybrid PIC code to model the tilt mode in FRCs

The results from QN3D are presented. QN3D is a 3-dimensional hybrid particle-in-cell code designed to run efficiently on the Cray-2 Multiprocessor. The chief application has been to the tilt mode instability in FRCs. QN3D accepts as input, the magnetic field, the ion particle density and the ion temperature on a two-dimensional r-z grid. These quantities are interpolated to the rest of the cartesian grid under the assumption of azimuthal symmetry. The particles are initialized with random numbers chosen according to the particle distributions input from the equilibrium code. The runs done here used equilibria computed by EQV, a kinetic equilibrium code.
Date: June 1, 1987
Creator: Horowitz, E. J. & Shumaker, D. E.
System: The UNT Digital Library
3-megajoule heavy-ion fusion driver (open access)

3-megajoule heavy-ion fusion driver

The initiation of inertial confinement fusion reactions with a heavy ion particle beam has been under intensive study since 1976, and the progress of this study is principally documented in the proceedings of annual workshops held by US National Laboratories. At this time a 3MJ, 150 TW, ion beam is a good choice to initiate microexplosions with energy gain of 100. The Lawrence Berkeley Laboratory has made systems studies based on a Linear Induction Accelerator to meet the beam requirements. The accelerator system, expected performance and cost, and technical problems to be addressed in the near future are discussed.
Date: June 1, 1981
Creator: Faltens, A.; Hoyer, E. & Keefe, D.
System: The UNT Digital Library
3 V manganese oxide electrode materials for lithium batteries. (open access)

3 V manganese oxide electrode materials for lithium batteries.

None
Date: June 20, 2000
Creator: Johnson, C. S. & Thackeray, M. M.
System: The UNT Digital Library
The 4.8 GHz LHC Schottky pick-up system (open access)

The 4.8 GHz LHC Schottky pick-up system

The LHC Schottky observation system is based on traveling wave type high sensitivity pickup structures operating at 4.8 GHz. The choice of the structure and operating frequency is driven by the demanding LHC impedance requirements, where very low impedance is required below 2 GHz, and good sensitivity at the selected band at 4.8 GHz. A sophisticated filtering and triple down -mixing signal processing chain has been designed and implemented in order to achieve the specified 100 dB instantaneous dynamic range without range switching. Detailed design aspects for the complete systems and test results without beam are presented and discussed.
Date: June 1, 2007
Creator: Caspers, Fritz; Jimenez, Jose Miguel; Jones, Rhodri Owain; Kroyer, Tom; Vuitton, Christophe; Hamerla, Timothy W. et al.
System: The UNT Digital Library
4 kW Test of Solid Oxide Electrolysis Stacks with Advanced Electrode-Supported Cells (open access)

4 kW Test of Solid Oxide Electrolysis Stacks with Advanced Electrode-Supported Cells

A new test stand has been developed at the Idaho National Laboratory for multi-kW testing of solid oxide electrolysis stacks. This test stand will initially be operated at the 4 KW scale. The 4 kW tests will include two 60-cell stacks operating in parallel in a single hot zone. The stacks are internally manifolded with an inverted-U flow pattern and an active area of 100 cm2 per cell. Process gases to and from the two stacks are distributed from common inlet/outlet tubing using a custom base manifold unit that also serves as the bottom current collector plate. The solid oxide cells incorporate a negative-electrode-supported multi-layer design with nickel-zirconia cermet negative electrodes, thin-film yttria-stabilized zirconia electrolytes, and multi-layer lanthanum ferrite-based positive electrodes. Treated metallic interconnects with integral flow channels separate the cells and electrode gases. Sealing is accomplished with compliant mica-glass seals. A spring-loaded test fixture is used for mechanical stack compression. Due to the power level and the large number of cells in the hot zone, process gas flow rates are high and heat recuperation is required to preheat the cold inlet gases upstream of the furnace. Heat recuperation is achieved by means of two inconel tube-in-tube counter-flow heat exchangers. …
Date: June 1, 2012
Creator: O'Brien, J. E.; Zhang, X.; Housley, G. K.; Moore-McAteer, L. & Tao, G.
System: The UNT Digital Library
A 4 to 0.1 nm FEL Based on the SLAC Linac (open access)

A 4 to 0.1 nm FEL Based on the SLAC Linac

The author show that using existing electron gun technology and a high energy linac like the one at SLAC, it is possible to build a Free Electron Laser operating around the 4 nm water window. A modest improvement in the gun performance would further allow to extend the FEL to the 0.1 nm region. Such a system would produce radiation with a brightness many order of magnitude above that of any synchrotron radiation source, existing or under construction, with laser power in the multigawatt region and subpicosecond pulse length.
Date: June 5, 2012
Creator: Pellegrini, C.
System: The UNT Digital Library
5. 8 GHz ophthalmic microwave applicator for treatment of choroidal melanoma (open access)

5. 8 GHz ophthalmic microwave applicator for treatment of choroidal melanoma

We report on the use of a 5.8 GHz microwave applicator to treat choroidal melanoma (Greene) in rabbits. The physical requirements needed to treat these intraocular tumors are quite different from those encountered elsewhere in the body. From a trans-scleral approach the penetration needed is minimal (5 to 10 mm.). The fibrous sclera is the only structure between the heat source and the tumor. The sclera has a relatively low water content when compared to tumor. This fact in addition to the frequency dependent interactions of tissue and electromagnetic radiation, results in an advantage to the use of the 5.8 GHz microwave device in treating intraocular malignancies.
Date: June 1983
Creator: Finger, Paul T.; Packer, Samuel; Svitra, Paul; Paglione, Robert W.; Albert, Daniel M. & Chess, Jeremy
System: The UNT Digital Library
5. annual clean coal technology conference: powering the next millennium. Volume 2 (open access)

5. annual clean coal technology conference: powering the next millennium. Volume 2

The Fifth Annual Clean Coal Technology Conference focuses on presenting strategies and approaches that will enable clean coal technologies to resolve the competing, interrelated demands for power, economic viability, and environmental constraints associated with the use of coal in the post-2000 era. The program addresses the dynamic changes that will result from utility competition and industry restructuring, and to the evolution of markets abroad. Current projections for electricity highlight the preferential role that electric power will have in accomplishing the long-range goals of most nations. Increase demands can be met by utilizing coal in technologies that achieve environmental goals while keeping the cost- per-unit of energy competitive. Results from projects in the DOE Clean Coal Technology Demonstration Program confirm that technology is the pathway to achieving these goals. The industry/government partnership, cemented over the past 10 years, is focused on moving the clean coal technologies into the domestic and international marketplaces. The Fifth Annual Clean Coal Technology Conference provides a forum to discuss these benchmark issues and the essential role and need for these technologies in the post-2000 era. This volume contains technical papers on: advanced coal process systems; advanced industrial systems; advanced cleanup systems; and advanced power generation systems. …
Date: June 1, 1997
Creator: unknown
System: The UNT Digital Library
5-level polysilicon surface micromachine technology: Application to complex mechanical systems (open access)

5-level polysilicon surface micromachine technology: Application to complex mechanical systems

The authors recently reported on the development of a 5-level poly-ilicon surface micromachine fabrication process consisting of four levels of mechanical poly plus an electrical interconnect layer. They are now reporting on the first components designed for and fabricated in this process. These are demonstration systems, which definitively show that five levels of polysilicon provide greater performance, reliability, and significantly increased functionality. This new technology makes it possible to realize levels of system complexity that have so far only existed on paper, while simultaneously adding to the robustness of many of the individual subassemblies.
Date: June 1, 1998
Creator: Rodgers, M. S. & Sniegowski, J. J.
System: The UNT Digital Library
An 8 GeV H- multi-turn injection system for the Fermilab Main Injector (open access)

An 8 GeV H- multi-turn injection system for the Fermilab Main Injector

An 8 GeV superconducting linear accelerator (SCL) has been proposed [1] as a single stage H{sup -} injector into the Main Injector (MI) synchrotron . This would be the highest energy H{sup -} multi-turn injection system in the world. The conceptual design of an injection system has been further refined by addressing transverse phase space painting issues, chicane dipole fields and foil location, foil temperature issues, and initial longitudinal phase space painting simulations. We present the current state of design.
Date: June 1, 2007
Creator: Johnson, D. E.; Yoon, P.; Liaw, C. J.; Raparia, D. & Bebee-Wang, J.
System: The UNT Digital Library
An 8 GeV H- multi-turn injection system for the Fermilab Main Injector (open access)

An 8 GeV H- multi-turn injection system for the Fermilab Main Injector

None
Date: June 1, 2007
Creator: Johnson, D. E.; Yoon, P.; Liaw, C. J.; Raparia, D. & Bebee-Wang, J.
System: The UNT Digital Library
An 8-GeV Synchrotron-Based Proton Driver (open access)

An 8-GeV Synchrotron-Based Proton Driver

In January 2002, the Fermilab Director initiated a design study for a high average power, modest energy proton facility. Such a facility is a possible candidate for a construction project in the U.S. starting in the middle of this decade. The key technical element is a new machine, dubbed the ''Proton Driver,'' as a replacement of the present Booster. The study of an 8-GeV synchrotron-based proton driver has been completed and published. This paper will give a summary report, including machine layout and performance, optics, beam dynamics issues, technical systems design, civil construction, cost estimate and schedule.
Date: June 4, 2003
Creator: Chou, Weiren
System: The UNT Digital Library
10 (micro)m and 5 (micro)m Pinhole-Assisted Point-Projection Backlit Imaging for NIF (open access)

10 (micro)m and 5 (micro)m Pinhole-Assisted Point-Projection Backlit Imaging for NIF

Pinhole-assisted point-projection backlighting with 10{micro}m and 5 {micro}m pinholes placed a small distance of order 1 mm away from the backlighter produces images with large field of view and high resolution. Pinholes placed closely to high-power backlighter sources can vaporize and close due to x-ray driven ablation, thereby limiting the usefulness of this method. A study of streaked 1-D backlit imaging of 25 {micro}m W wires using the OMEGA laser is presented. The pinhole closure timescale for 10 {micro}m pinholes placed 0.45 mm and 1 mm distant from the backlighter is 1.3 ns and 2.2 ns, respectively. Similar timescales for 5 {micro}m pinholes is also presented. Successful wire imaging prior to pinhole closure is clearly demonstrated.
Date: June 5, 2001
Creator: Bullock, A. B.; Landen, O. L. & Bradley, D. K.
System: The UNT Digital Library