Renewable liquid reflecting zone plate
Toor, Arthur; Ryutov, Dmitri D.
2003-12-09
A renewable liquid reflecting zone plate. Electrodes are operatively connected to a dielectric liquid in a circular or other arrangement to produce a reflecting zone plate. A system for renewing the liquid uses a penetrable substrate.
Mankos, Marian; Shadman, Khashayar
2014-12-02
In this SBIR project, Electron Optica, Inc. (EOI) is developing a mirror electron monochromator (MirrorChrom) attachment to new and retrofitted electron microscopes (EMs) for improving the energy resolution of the EM from the characteristic range of 0.2-0.5 eV to the range of 10-50 meV. This improvement will enhance the characterization of materials by imaging and spectroscopy. In particular, the monochromator will refine the energy spectra characterizing materials, as obtained from transmission EMs [TEMs] fitted with electron spectrometers, and it will increase the spatial resolution of the images of materials taken with scanning EMs (SEMs) operated at low voltages. EOIs MirrorChrom technology utilizes a magnetic prism to simultaneously deflect the electron beam off the axis of the microscope column by 90 and disperse the electrons in proportional to their energies into a module with an electron mirror and a knife-edge. The knife-edge cuts off the tails of the energy distribution to reduce the energy spread of the electrons that are reflected, and subsequently deflected, back into the microscope column. The knife-edge is less prone to contamination, and thereby charging, than the conventional slits used in existing monochromators, which improves the reliability and stability of the module. The overall design of the MirrorChrom exploits the symmetry inherent in reversing the electron trajectory in order to maintain the beam brightness a parameter that impacts how well the electron beam can be focused downstream onto a sample. During phase I, EOI drafted a set of candidate monochromator architectures and evaluated the trade-offs between energy resolution and beam current to achieve the optimum design for three particular applications with market potential: increasing the spatial resolution of low voltage SEMs, increasing the energy resolution of low voltage TEMs (beam energy of 5-20 keV), and increasing the energy resolution of conventional TEMs (beam energy of
Double patterning HSQ processes of zone plates for 10 nm diffraction...
Office of Scientific and Technical Information (OSTI)
... Using the new process, we successfully realized zone plates of 10 nm and 12 nm outermost zones. Fig. 3 shows the SEM micrographs of the zone plates outer regions. The zone plates ...
New Zone Plate for Soft X-Ray Microscopy at 15-nm Spatial Resolution
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New Zone Plate for Soft X-Ray Microscopy at 15-nm Spatial Resolution New Zone Plate for Soft X-Ray Microscopy at 15-nm Spatial Resolution Print Wednesday, 31 August 2005 00:00 ...
Monochromator Crystal Glitch Library
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
SSRL's Monochromator Crystal Glitch Library allows users to view glitch spectra online, list specific crystal orientations, and download PDF files of the glitch spectra. (Specialized Interface)
Demonstration of 12 nm resolution Fresnel zone plate lens based soft x-ray microscopy
Chao, W.; Kim, J.; Rekawa, S.; Fischer, P.; Anderson, E. H.
2009-06-05
To extend soft x-ray microscopy to a resolution of order 10 nm or better, we developed a new nanofabrication process for Fresnel zone plate lenses. The new process, based on the double patterning technique, has enabled us to fabricate high quality gold zone plates with 12 nm outer zones. Testing of the zone plate with the full-field transmission x-ray microscope, XM-1, in Berkeley, showed that the lens clearly resolved 12 nm lines and spaces. This result represents a significant step towards 10 nm resolution and beyond.
Mook, Jr., Herbert A. (Oak Ridge, TN)
1985-01-01
In one aspect, the invention is an improved pulsed-neutron monochromator of the vibrated-crystal type. The monochromator is designed to provide neutron pulses which are characterized both by short duration and high density. A row of neutron-reflecting crystals is disposed in a neutron beam to reflect neutrons onto a common target. The crystals in the row define progressively larger neutron-scattering angles and are vibrated sequentially in descending order with respect to the size of their scattering angles, thus generating neutron pulses which arrive simultaneously at the target. Transducers are coupled to one end of the crystals to vibrate them in an essentially non-resonant mode. The transducers propagate transverse waves in the crystal which progress longitudinally therein. The wave are absorbed at the undriven ends of the crystals by damping material mounted thereon. In another aspect, the invention is a method for generating neutron pulses characterized by high intensity and short duration.
Mook, H.A. Jr.
1984-01-01
In one aspect, the invention is an improved pulsed-neutron monochromator of the vibrated-crystal type. The monochromator is designed to provide neutron pulses which are characterized both by short duration and high density. A row of neutron-reflecting crystals is disposed in a neutron beam to reflect neutrons onto a common target. The crystals in the row define progressively larger neutron-scattering angles and are vibrated sequentially in descending order with respect to the size of their scattering angles, thus generating neutron pulses which arrive simultaneously at the target. Transducers are coupled to one end of the crystals to vibrate them in an essentially non-resonant mode. The transducers propagate transverse waves in the crystal which progress longitudinally therein. The waves are absorbed at the undriven ends of the crystals by damping material mounted thereon. In another aspect, the invention is a method for generating neutron pulses characterized by high intensity and short duration.
New Zone Plate for Soft X-Ray Microscopy at 15-nm Spatial Resolution
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New Zone Plate for Soft X-Ray Microscopy at 15-nm Spatial Resolution New Zone Plate for Soft X-Ray Microscopy at 15-nm Spatial Resolution Print Wednesday, 31 August 2005 00:00 Analytical tools that combine spatial resolution with elemental and chemical identification at the nanometer scale along with large penetration depth are indispensable for the life and physical sciences. The XM-1 soft x-ray microscope at the ALS produces images that not only reveal structures but can identify their
New Zone Plate for Soft X-Ray Microscopy at 15-nm Spatial Resolution
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
New Zone Plate for Soft X-Ray Microscopy at 15-nm Spatial Resolution Print Analytical tools that combine spatial resolution with elemental and chemical identification at the nanometer scale along with large penetration depth are indispensable for the life and physical sciences. The XM-1 soft x-ray microscope at the ALS produces images that not only reveal structures but can identify their chemical elements and measure magnetic and other properties as well. Now a new method for creating optical
New Zone Plate for Soft X-Ray Microscopy at 15-nm Spatial Resolution
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
New Zone Plate for Soft X-Ray Microscopy at 15-nm Spatial Resolution Print Analytical tools that combine spatial resolution with elemental and chemical identification at the nanometer scale along with large penetration depth are indispensable for the life and physical sciences. The XM-1 soft x-ray microscope at the ALS produces images that not only reveal structures but can identify their chemical elements and measure magnetic and other properties as well. Now a new method for creating optical
New Zone Plate for Soft X-Ray Microscopy at 15-nm Spatial Resolution
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
New Zone Plate for Soft X-Ray Microscopy at 15-nm Spatial Resolution Print Analytical tools that combine spatial resolution with elemental and chemical identification at the nanometer scale along with large penetration depth are indispensable for the life and physical sciences. The XM-1 soft x-ray microscope at the ALS produces images that not only reveal structures but can identify their chemical elements and measure magnetic and other properties as well. Now a new method for creating optical
APS high heat load monochromator
Lee, W.K.; Mills, D.
1993-02-01
This document contains the design specifications of the APS high heat load (HHL) monochromator and associated accessories as of February 1993. It should be noted that work is continuing on many parts of the monochromator including the mechanical design, crystal cooling designs, etc. Where appropriate, we have tried to add supporting documentation, references to published papers, and calculations from which we based our decisions. The underlying philosophy behind performance specifications of this monochromator was to fabricate a device that would be useful to as many APS users as possible, that is, the design should be as generic as possible. In other words, we believe that this design will be capable of operating on both bending magnet and ID beamlines (with the appropriate changes to the cooling and crystals) with both flat and inclined crystal geometries and with a variety of coolants. It was strongly felt that this monochromator should have good energy scanning capabilities over the classical energy range of about 4 to 20 keywith Si (111) crystals. For this reason, a design incorporating one rotation stage to drive both the first and second crystals was considered most promising. Separate rotary stages for the first and second crystals can sometimes provide more flexibility in their capacities to carry heavy loads (for heavily cooled first crystals or sagittal benders of second crystals), but their tuning capabilities were considered inferior to the single axis approach.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Gleber, Sophie -Charlotte; Wojcik, Michael; Liu, Jie; Roehrig, Chris; Cummings, Marvin; Vila-Comamala, Joan; Li, Kenan; Lai, Barry; Shu, Deming; Vogt, Stefan
2014-11-05
Focusing efficiency of Fresnel zone plates (FZPs) for X-rays depends on zone height, while the achievable spatial resolution depends on the width of the finest zones. FZPs with optimal efficiency and sub-100-nm spatial resolution require high aspect ratio structures which are difficult to fabricate with current technology especially for the hard X-ray regime. A possible solution is to stack several zone plates. To increase the number of FZPs within one stack, we first demonstrate intermediate-field stacking and apply this method by stacks of up to five FZPs with adjusted diameters. Approaching the respective optimum zone height, we maximized efficiencies formorehigh resolution focusing at three different energies, 10, 11.8, and 25 keV.less
High resolution EUV monochromator/spectrometer
Koike, Masako
1996-06-18
This invention is related to a monochromator which employs a spherical mirror, a traveling plane mirror with simultaneous rotation, and a varied spacing plane grating. The divergent beam from the entrance slit is converged by the spherical mirror located at the various positions in the monochromator depending of the inventive system. To provide the meaningful diffraction efficiencies and to reduce unwanted higher order lights, the deviation angle subtending the incidence and diffraction beams for the plane grating is varied with the position of the traveling plane mirror with simultaneous rotation located in the front or back of the plane grating with wavelength scanning. The outgoing beam from the monochromator goes through the fixed exit slit and has same beam direction regardless of the scanning wavelength. The combination of properly designed motions of the plane mirror and novel varied-spacing parameters of the inventive plane grating corrects the aberrations and focuses the monochromatic spectral image on the exit slit, enabling measurements at high spectral resolution. 10 figs.
High resolution EUV monochromator/spectrometer
Koike, Masako
1996-01-01
This invention is related to a monochromator which employs a spherical mirror, a traveling plane mirror with simultaneous rotation, and a varied spacing plane grating. The divergent beam from the entrance slit is converged by the spherical mirror located at the various positions in the monochromator depending of the inventive system. To provide the meaningful diffraction efficiencies and to reduce unwanted higher order lights, the deviation angle subtending the incidence and diffraction beams for the plane grating is varied with the position of the traveling plane mirror with simultaneous rotation located in the front or back of the plane grating with wavelength scanning. The outgoing beam from the monochromator goes through the fixed exit slit and has same beam direction regardless of the scanning wavelength. The combination of properly designed motions of the plane mirror and novel varied-spacing parameters of the inventive plane grating corrects the aberrations and focuses the monochromatic spectral image on the exit slit, enabling measurements at high spectral resolution.
Focusing monochromators for high energy synchrotron radiation
Suortti, P. )
1992-01-01
Bent crystals are introduced as monochromators for high energy synchrotron radiation. The reflectivity of the crystal can be calculated reliably from a model where the bent crystal is approximated by a stack of lamellas, which have a gradually changing angle of reflection. The reflectivity curves of a 4 mm thick, asymmetrically cut ({chi}=9.5{degree}) Si(220) crystal are measured using 150 keV radiation and varying the bending radius from 25 to 140 m. The width of the reflectivity curve is up to 50 times the Darwin width of the reflection, and the maximum reflectivity exceeds 80%. The crystal is used as a monochromator in Compton scattering measurements. The source is on the focusing circle, so that the resolution is limited essentially by the detector/analyzer. A wide bandpass, sharply focused beam is attained when the source is outside the focusing circle in the transmission geometry. In a test experiment. 10{sup 12} photons on an area of 2 mm{sup 2} was observed. The energy band was about 4 keV centered at 40 keV. A powder diffraction pattern of a few reflections of interest was recorded by an intrinsic Ge detector, and this demonstrated that a structural transition can be followed at intervals of a few milliseconds.
Asymmetrically cut crystals for synchrotron radiation monochromators
Sanchez del Rio, M. ); Cerrina, F. )
1992-01-01
Asymmetrically cut crystals are interesting for use in synchrotron radiation monochromators because of their good energy resolution characteristics and their focusing properties. Ray tracing codes, such as SHADOW, are very efficient in the design and development of new optical devices. In order to determine the convenience of using asymmetrically cut crystals for x-ray monochromators, SHADOW has been extended to include these kinds of crystals. The physical approach to ray tracing asymmetrically cut crystals is based on the coexistence of two periodic structures. One of these is the bulk periodic structure of the Bragg planes. Such a structure determines the existence of a rocking curve near the Bragg condition, and is implemented in SHADOW following the Darwin--Prins formalism of the dynamical theory of diffraction. The second periodic structure is a one-dimensional grating on the crystal surface, formed by the truncation of the lattice planes with the surface. This grating is responsible for the focusing properties of these crystals and plays an essential role in determining the trajectory of the rays. The combination of an asymmetric crystal and a nonplanar surface can be easily achieved by bending (Johann case) to provide improved properties. More complex cases such as the ground-bent crystals (i.e., Johansson geometry) can be considered as a particular case of asymmetrical crystals in which the angle between the Bragg planes and the surface change along the crystal surface. All these cases have been implemented in SHADOW.
Holographic optical grating and method for optimizing monochromator configuration
Koike, Masato (Moraga, CA)
1999-01-01
This invention comprises a novel apparatus for recording a holographic groove pattern on a diffraction grating blank. The recording apparatus is configured using newly developed groups of analytical equations. The invention further comprises the novel holographic diffraction grating made with the inventive recording apparatus. The invention additionally comprises monochromators and spectrometers equipped with the inventive holographic diffraction grating. Further, the invention comprises a monochromator configured to reduce aberrations using a newly developed group of analytical equations. Additionally, the invention comprises a method to reduce aberrations in monochromators and spectrometers using newly developed groups of analytical equations.
MONO: A program to calculate synchrotron beamline monochromator throughputs
Chapman, D.
1989-01-01
A set of Fortran programs have been developed to calculate the expected throughput of x-ray monochromators with a filtered synchrotron source and is applicable to bending magnet and wiggler beamlines. These programs calculate the normalized throughput and filtered synchrotron spectrum passed by multiple element, flat un- focussed monochromator crystals of the Bragg or Laue type as a function of incident beam divergence, energy and polarization. The reflected and transmitted beam of each crystal is calculated using the dynamical theory of diffraction. Multiple crystal arrangements in the dispersive and non-dispersive mode are allowed as well as crystal asymmetry and energy or angle offsets. Filters or windows of arbitrary elemental composition may be used to filter the incident synchrotron beam. This program should be useful to predict the intensities available from many beamline configurations as well as assist in the design of new monochromator and analyzer systems. 6 refs., 3 figs.
Synchronized monochromator and insertion device energy scans at SLS
Krempasky, J.; Flechsig, U.; Korhonen, T.; Zimoch, D.; Quitmann, Ch.; Nolting, F.
2010-06-23
Synchronous monochromator and insertion device energy scans were implemented at the Surfaces/Interfaces:Microscopy (SIM) beamline in order to provide the users fast X-ray magnetic dichroism studies (XMCD). A simple software control scheme is proposed based on a fast monochromator run-time energy readback which quickly updates the insertion device requested energy during an on-the-fly X-ray absorption scan (XAS). In this scheme the Plain Grating Monochromator (PGM) motion control, being much slower compared with the insertion device (APPLE-II type undulator), acts as a 'master' controlling the undulator 'slave' energy position. This master-slave software implementation exploits EPICS distributed device control over computer network and allows for a quasi-synchronous motion control combined with data acquisition needed for the XAS or XMCD experiment.
High energy resolution, high angular acceptance crystal monochromator
Alp, Ercan E.; Mooney, Timothy M.; Toellner, Thomas
1996-06-04
A 4-bounce dispersive crystal monochromator reduces the bandpass of synchrotron radiation to a 10-50 meV range without sacrificing angular acceptance. The monochromator includes the combination of an asymmetrical channel-cut single crystal of lower order reflection and a symmetrical channel-cut single crystal of higher order reflection in a nested geometric configuration. In the disclosed embodiment, a highly asymmetrically cut (.alpha.=20) outer silicon crystal (4 2 2) with low order reflection is combined with a symmetrically cut inner silicon crystal (10 6 4) with high order reflection to condition a hard x-ray component (5-30 keV) of synchrotron radiation down to the .mu.eV-neV level. Each of the crystals is coupled to the combination of a positioning inchworm and angle encoder via a respective rotation stage for accurate relative positioning of the crystals and precise energy tuning of the monochromator.
High energy resolution, high angular acceptance crystal monochromator
Alp, E.E.; Mooney, T.M.; Toellner, T.
1996-06-04
A 4-bounce dispersive crystal monochromator reduces the bandpass of synchrotron radiation to a 10-50 meV range without sacrificing angular acceptance. The monochromator includes the combination of an asymmetrical channel-cut single crystal of lower order reflection and a symmetrical channel-cut single crystal of higher order reflection in a nested geometric configuration. In the disclosed embodiment, a highly asymmetrically cut ({alpha}=20) outer silicon crystal (4 2 2) with low order reflection is combined with a symmetrically cut inner silicon crystal (10 6 4) with high order reflection to condition a hard x-ray component (5--30 keV) of synchrotron radiation down to the {micro}eV-neV level. Each of the crystals is coupled to the combination of a positioning inchworm and angle encoder via a respective rotation stage for accurate relative positioning of the crystals and precise energy tuning of the monochromator. 7 figs.
Monochromator for continuous spectrum x-ray radiation
Staudenmann, J.L.; Liedl, G.L.
1983-12-02
A monochromator for use with synchrotron x-ray radiation comprises two diffraction means which can be rotated independently and independent means for translationally moving one diffraction means with respect to the other. The independence of the rotational and translational motions allows Bragg angles from 3.5/sup 0/ to 86.5/sup 0/, and facilitates precise and high-resolution monochromatization over a wide energy range. The diffraction means are removably mounted so as to be readily interchangeable, which allows the monochromator to be used for both non-dispersive and low dispersive.
Monochromator for continuous spectrum x-ray radiation
Staudenmann, Jean-Louis; Liedl, Gerald L.
1987-07-07
A monochromator for use with synchrotron x-ray radiation comprises two diffraction means which can be rotated independently and independent means for translationally moving one diffraction means with respect to the other. The independence of the rotational and translational motions allows Bragg angles from 3.5.degree. to 86.5.degree., and facilitates precise and high-resolution monochromatization over a wide energy range. The diffraction means are removably mounted so as to be readily interchangeable, which allows the monochromator to be used for both non-dispersive and low dispersive work.
Optical system for high resolution spectrometer/monochromator
Hettrick, Michael C.; Underwood, James H.
1988-01-01
An optical system for use in a spectrometer or monochromator employing a mirror which reflects electromagnetic radiation from a source to converge with same in a plane. A straight grooved, varied-spaced diffraction grating receives the converging electromagnetic radiation from the mirror and produces a spectral image for capture by a detector, target or like receiver.
Optical system for high resolution spectrometer/monochromator
Hettrick, M.C.; Underwood, J.H.
1988-10-11
An optical system for use in a spectrometer or monochromator employing a mirror which reflects electromagnetic radiation from a source to converge with same in a plane is disclosed. A straight grooved, varied-spaced diffraction grating receives the converging electromagnetic radiation from the mirror and produces a spectral image for capture by a detector, target or like receiver. 11 figs.
Amemiya, Kenta; Toyoshima, Akio; Kikuchi, Takashi; Kosuge, Takashi; Nigorikawa, Kazuyuki; Sumii, Ryohei; Ito, Kenji
2010-06-23
The design and commissioning of a new soft X-ray beamline, BL-16A, at the Photon Factory is presented. The beamline consists of a pre-focusing mirror, an entrance slit, a variable-included-angle varied-line-spacing plane grating monochromator, and a post-focusing system as usual, and provides circularly and linearly polarized soft X rays in the energy range 200-1500 eV with an APPLE-II type undulator. The commissioning procedure for the beamline optics is described in detail, especially the check of the focal position for the zero-th order and diffracted X rays.
Back-scattering channel-cut high-resolution monochromator for inelastic x-ray scattering
Kushnir, V.I.; Abbamonte, P.M.; Macrander, A.T.; Schwoerer-Boehning, M.
1997-08-01
We report on a design and on some experimental results for the performance of a new high energy resolution monochromator. It is a large channel-cut Si crystal with a 197 mm separation between the two faces designed to operate in a near-backscattering regime. The device was tested as a second monochromator on Sector 3 of the Synchrotron Radiation Instrumentation Collaborative Access Team (SRI-CAT) at the Advanced Photon Source using the Si(777) reflection at a photon energy of 13.84 keV. The same monochromator can be used for other energies with reflections of the type (hhh). Special care has been taken to equalize the temperature of the two faces by employing a Peltier heat pump. A Si(111) double-crystal pre-monochromator designed to withstand the high heat load of the undulator radiation was used upstream on the beamline. The measured throughput efficiency of the Si(777) channel-cut monochromator was less ideal by a factor of 1.9. Dynamical diffraction theory was used to calculate the throughput of an ideally perfect crystal.
Ultra-stable sub-meV monochromator for hard X-rays
Toellner, T. S.; Collins, J.; Goetze, K.; Hu, M. Y.; Preissner, C.; Trakhtenberg, E.; Yan, L.
2015-07-17
A high-resolution silicon monochromator suitable for 21.541 keV synchrotron radiation is presented that produces a bandwidth of 0.27 meV. The operating energy corresponds to a nuclear transition in ^{151}Eu. The first-of-its-kind, fully cryogenic design achieves an energy-alignment stability of 0.017 meV r.m.s. per day, or a 100-fold improvement over other meV-monochromators, and can tolerate higher X-ray power loads than room-temperature designs of comparable resolution. This offers the potential for significantly more accurate measurements of lattice excitation energies using nuclear resonant vibrational spectroscopy if combined with accurate energy calibration using, for example, high-speed Doppler shifting. The design of the monochromator along with its performance and impact on transmitted beam properties are presented.
Inclined monochromator for high heat-load synchrotron x-ray radiation
Khounsary, Ali M.
1994-01-01
A double crystal monochromator including two identical, parallel crystals, each of which is cut such that the normal to the diffraction planes of interest makes an angle less than 90 degrees with the surface normal. Diffraction is symmetric, regardless of whether the crystals are symmetrically or asymmetrically cut, enabling operation of the monochromator with a fixed plane of diffraction. As a result of the inclination of the crystal surface, an incident beam has a footprint area which is elongated both vertically and horizontally when compared to that of the conventional monochromator, reducing the heat flux of the incident beam and enabling more efficient surface cooling. Because after inclination of the crystal only a fraction of thermal distortion lies in the diffraction plane, slope errors and the resultant misorientation of the diffracted beam are reduced.
Ultra-stable sub-meV monochromator for hard X-rays
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Toellner, T. S.; Collins, J.; Goetze, K.; Hu, M. Y.; Preissner, C.; Trakhtenberg, E.; Yan, L.
2015-07-17
A high-resolution silicon monochromator suitable for 21.541 keV synchrotron radiation is presented that produces a bandwidth of 0.27 meV. The operating energy corresponds to a nuclear transition in 151Eu. The first-of-its-kind, fully cryogenic design achieves an energy-alignment stability of 0.017 meV r.m.s. per day, or a 100-fold improvement over other meV-monochromators, and can tolerate higher X-ray power loads than room-temperature designs of comparable resolution. This offers the potential for significantly more accurate measurements of lattice excitation energies using nuclear resonant vibrational spectroscopy if combined with accurate energy calibration using, for example, high-speed Doppler shifting. The design of the monochromator alongmore » with its performance and impact on transmitted beam properties are presented.« less
Inclined monochromator for high heat-load synchrotron x-ray radiation
Khounsary, A.M.
1994-02-15
A double crystal monochromator is described including two identical, parallel crystals, each of which is cut such that the normal to the diffraction planes of interest makes an angle less than 90 degrees with the surface normal. Diffraction is symmetric, regardless of whether the crystals are symmetrically or asymmetrically cut, enabling operation of the monochromator with a fixed plane of diffraction. As a result of the inclination of the crystal surface, an incident beam has a footprint area which is elongated both vertically and horizontally when compared to that of the conventional monochromator, reducing the heat flux of the incident beam and enabling more efficient surface cooling. Because after inclination of the crystal only a fraction of thermal distortion lies in the diffraction plane, slope errors and the resultant misorientation of the diffracted beam are reduced. 11 figures.
Macrander, A.T.; Schwoerer-Boehning, M.; Abbamonte, P.M.; Hu, M.
1997-08-01
A monochromator for use at 13.84 keV with a calculated bandpass of 5.2 meV was designed built, and tested. Tuning was performed by rotating the inner crystal of a pair of nested silicon channel-cut crystals. The inner crystal employs the (884) reflection, and the outer crystal employs a collimating asymmetric (422) reflection (dynamical asymmetry factor, b, equal to {minus}17.5). Tests were done with a double-crystal Si(111) pre-monochromator situated upstream of the high resolution monochromator and a Si(777) backscattering crystal situated downstream. For this optical arrangement an ideal value of 6.3 meV as calculated by x-ray dynamical diffraction theory applies for the FWHM of the convolution of the net monochromator reflectivity function with that of the Si(777) reflection. This calculated value is to be compared to the value of 7.1 meV measured by tuning the high resolution monochromator. Measured efficiencies were less than ideal by a factor of 3.2 to 4.9, where the larger flux reduction factors were found with higher positron storage ring currents.
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2.1 Print National Center for X-Ray Tomography (NCXT) Scientific discipline: Biology GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics Bend magnet Energy range 400 - 1300 eV Monochromator Zone-plate linear Measured flux (1.9 GeV, 400 mA) Images with 2048 x 2048 pixels Resolving power (E/ƒ¢E) 500-700 Endstations X-ray microscope (XM-2) Characteristics Full-field soft x-ray transmission microscope Spatial resolution Zone-plate dependent Detectors Back-thinned 2048- x 2048-pixel
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2.1 Print National Center for X-Ray Tomography (NCXT) Scientific discipline: Biology GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics Bend magnet Energy range 400 - 1300 eV Monochromator Zone-plate linear Measured flux (1.9 GeV, 400 mA) Images with 2048 x 2048 pixels Resolving power (E/ƒ¢E) 500-700 Endstations X-ray microscope (XM-2) Characteristics Full-field soft x-ray transmission microscope Spatial resolution Zone-plate dependent Detectors Back-thinned 2048- x 2048-pixel
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Beamline 2.1 Print National Center for X-Ray Tomography (NCXT) Scientific discipline: Biology GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics Bend magnet Energy range 400 - 1300 eV Monochromator Zone-plate linear Measured flux (1.9 GeV, 400 mA) Images with 2048 x 2048 pixels Resolving power (E/ƒ¢E) 500-700 Endstations X-ray microscope (XM-2) Characteristics Full-field soft x-ray transmission microscope Spatial resolution Zone-plate dependent Detectors Back-thinned 2048- x
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2.1 Print National Center for X-Ray Tomography (NCXT) Scientific discipline: Biology GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics Bend magnet Energy range 400 - 1300 eV Monochromator Zone-plate linear Measured flux (1.9 GeV, 400 mA) Images with 2048 x 2048 pixels Resolving power (E/ƒ¢E) 500-700 Endstations X-ray microscope (XM-2) Characteristics Full-field soft x-ray transmission microscope Spatial resolution Zone-plate dependent Detectors Back-thinned 2048- x 2048-pixel
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Beamline 2.1 Print National Center for X-Ray Tomography (NCXT) Scientific discipline: Biology GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics Bend magnet Energy range 400 - 1300 eV Monochromator Zone-plate linear Measured flux (1.9 GeV, 400 mA) Images with 2048 x 2048 pixels Resolving power (E/ƒ¢E) 500-700 Endstations X-ray microscope (XM-2) Characteristics Full-field soft x-ray transmission microscope Spatial resolution Zone-plate dependent Detectors Back-thinned 2048- x
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Beamline 2.1 Print National Center for X-Ray Tomography (NCXT) Scientific discipline: Biology GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics Bend magnet Energy range 400 - 1300 eV Monochromator Zone-plate linear Measured flux (1.9 GeV, 400 mA) Images with 2048 x 2048 pixels Resolving power (E/ƒ¢E) 500-700 Endstations X-ray microscope (XM-2) Characteristics Full-field soft x-ray transmission microscope Spatial resolution Zone-plate dependent Detectors Back-thinned 2048- x
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Beamline 2.1 Print National Center for X-Ray Tomography (NCXT) Scientific discipline: Biology GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics Bend magnet Energy range 400 - 1300 eV Monochromator Zone-plate linear Measured flux (1.9 GeV, 400 mA) Images with 2048 x 2048 pixels Resolving power (E/ƒ¢E) 500-700 Endstations X-ray microscope (XM-2) Characteristics Full-field soft x-ray transmission microscope Spatial resolution Zone-plate dependent Detectors Back-thinned 2048- x
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2.1 Beamline 2.1 Print Tuesday, 20 October 2009 08:16 National Center for X-Ray Tomography (NCXT) Scientific discipline: Biology GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics Bend magnet Energy range 400 - 1300 eV Monochromator Zone-plate linear Measured flux (1.9 GeV, 400 mA) Images with 2048 x 2048 pixels Resolving power (E/ƒ¢E) 500-700 Endstations X-ray microscope (XM-2) Characteristics Full-field soft x-ray transmission microscope Spatial resolution Zone-plate
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2.1 Print National Center for X-Ray Tomography (NCXT) Scientific discipline: Biology GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics Bend magnet Energy range 400 - 1300 eV Monochromator Zone-plate linear Measured flux (1.9 GeV, 400 mA) Images with 2048 x 2048 pixels Resolving power (E/ƒ¢E) 500-700 Endstations X-ray microscope (XM-2) Characteristics Full-field soft x-ray transmission microscope Spatial resolution Zone-plate dependent Detectors Back-thinned 2048- x 2048-pixel
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2.1 Print National Center for X-Ray Tomography (NCXT) Scientific discipline: Biology GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics Bend magnet Energy range 400 - 1300 eV Monochromator Zone-plate linear Measured flux (1.9 GeV, 400 mA) Images with 2048 x 2048 pixels Resolving power (E/ƒ¢E) 500-700 Endstations X-ray microscope (XM-2) Characteristics Full-field soft x-ray transmission microscope Spatial resolution Zone-plate dependent Detectors Back-thinned 2048- x 2048-pixel
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
2.1 Print National Center for X-Ray Tomography (NCXT) Scientific discipline: Biology GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics Bend magnet Energy range 400 - 1300 eV Monochromator Zone-plate linear Measured flux (1.9 GeV, 400 mA) Images with 2048 x 2048 pixels Resolving power (E/ƒ¢E) 500-700 Endstations X-ray microscope (XM-2) Characteristics Full-field soft x-ray transmission microscope Spatial resolution Zone-plate dependent Detectors Back-thinned 2048- x 2048-pixel
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
2.1 Print National Center for X-Ray Tomography (NCXT) Scientific discipline: Biology GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics Bend magnet Energy range 400 - 1300 eV Monochromator Zone-plate linear Measured flux (1.9 GeV, 400 mA) Images with 2048 x 2048 pixels Resolving power (E/ƒ¢E) 500-700 Endstations X-ray microscope (XM-2) Characteristics Full-field soft x-ray transmission microscope Spatial resolution Zone-plate dependent Detectors Back-thinned 2048- x 2048-pixel
De Bruijn, D.; Van Zuylen, P. ); Kruizinga, G. , P.O. Box 93138, 2509 AC Den Haag State University of Utrecht, Sorbonnelaan 16, 3508 TB Utrecht )
1992-01-01
A Si(220) double-crystal monochromator for the energy range 10--30 keV is presented. It will be used for EXAFS as well as powder diffraction measurements. To determine the requirements for this monochromator we looked, apart from mean considerations, at the requirements dictated by EXAFS in transmission mode. For good data analyses the proper shape, amplitude, and location at the energy axis of each wiggle is required. Moreover it is essential to separate the wiggles from background and noise. For the latter a high flux through the sample is desirable, which can be achieved by horizontal focusing of the beam. For that we have chosen to bend the second crystal sagitally. The sagittal bending radius is adjustable between 50 and 0.8 m, because for different energies different sagittal radii are necessary to focus the beam on the sample. The mean meridional radius of the second crystal is fixed at 130 m, which is an optimization for 20 keV. The meridional radius of the first crystal can be tuned between 100 and 500 m. When this radius is set to 130 m the energy resolution is calculated to be 6, 3, and 35 eV for 10, 20, and 30 keV (for perfectly bent crystals). By changing the meridional radius of the first crystal, future users of this monochromator can make the trade off between resolution and intensity. Movement of the monochromator exit beam, during a scan, will occur due to the monochromator geometry, but is reduced as much as possible by using an asymmetrically cut second crystal, with an asymmetry angle of 2.5{degree}. The average exit beam movement of the monochromator for a 1-keV scan is 20 {mu}m. For 40% of the energy range (10--30 keV) the exit beam position remains within 10 {mu}m. For the second crystal no translation stage is used.
Floyd, M.A.
1980-03-01
A computer controlled, scanning monochromator system specifically designed for the rapid, sequential determination of the elements is described. The monochromator is combined with an inductively coupled plasma excitation source so that elements at major, minor, trace, and ultratrace levels may be determined, in sequence, without changing experimental parameters other than the spectral line observed. A number of distinctive features not found in previously described versions are incorporated into the system here described. Performance characteristics of the entire system and several analytical applications are discussed.
Single-crystal sapphire microstructure for high-resolution synchrotron X-ray monochromators
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Asadchikov, Victor E.; Butashin, Andrey V.; Buzmakov, Alexey V.; Deryabin, Alexander N.; Kanevsky, Vladimir M.; Prokhorov, Igor A.; Roshchin, Boris S.; Volkov, Yuri O.; Zolotov, Dennis A.; Jafari, Atefeh; et al
2016-03-22
We report on the growth and characterization of several sapphire single crystals for the purpose of x-ray optics applications. Structural defects were studied by means of laboratory double-crystal X-ray diffractometry and white beam synchrotron-radiation topography. The investigations confirmed that the main defect types are dislocations. The best quality crystal was grown using the Kyropoulos technique with a dislocation density of 102-103 cm-2 and a small area with approximately 2*2 mm2 did not show dislocation contrast in many reflections and has suitable quality for application as a backscattering monochromator. As a result, a clear correlation between growth rate and dislocation densitymore » is observed, though growth rate is not the only parameter impacting the quality.« less
The sapphire backscattering monochromator at the Dynamics beamline P01 of PETRA III
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Alexeev, P.; Asadchikov, V.; Bessas, D.; Butashin, A.; Deryabin, A.; Dill, F. -U.; Ehnes, A.; Herlitschke, M.; Hermann, R. P.; Jafari, A.; et al
2016-02-23
Here, we report on a high resolution sapphire backscattering monochromator installed at the Dynamics beamline P01 of PETRA III. The device enables nuclear resonance scattering experiments on M ossbauer isotopes with transition energies between 20 and 60 keV with sub-meV to meV resolution. In a first performance test with 119Sn nuclear resonance at a X-ray energy of 23.88 keV an energy resolution of 1.34 meV was achieved. Moreover, the device extends the field of nuclear resonance scattering at the PETRA III synchrotron light source to many further isotopes like 151Eu, 149Sm, 161Dy, 125Te and 121Sb.
Poletto, L.; Villoresi, P.; Benedetti, E.; Ferrari, F.; Stagira, S.; Sansone, G.; Nisoli, M.
2008-07-15
Ultrafast extreme-ultraviolet pulses are spectrally selected by a time-delay-compensated grating monochromator. The intrinsic very short duration of the pulses is obtained by exploiting the high-order harmonic generation process. The temporal characterization of the harmonic pulses is obtained using a cross-correlation method: pulses as short as 8 fs are measured at the output of the monochromator in the case of the 23rd harmonic. This value is in agreement with the expected duration of such pulses, indicating that the influence of the monochromator is negligible. The photon flux has been measured with a calibrated photodiode, pointing out the good efficiency of the monochromator, derived by the exploitation for the two gratings of the conical diffraction mounting.
Feng, Jun, Thompson,A.C.; Padmore,H.A.
2000-02-24
In collaboration with the Chemistry Department at the University of California at Berkeley, the ALS is building a beamline for structural determination in materials chemistry. The system will be used for single crystal x-ray diffraction on crystals that are too small or disordered for examination on laboratory systems, and typically will be used for crystals in the 5 - 20 micron regime. As some of the materials being designed are of the size of small proteins, phasing using direct methods is problematic, and so use of multiple wavelength anomalous dispersion techniques will be employed in many cases. The production of new compounds has been revolutionized in recent years with the development of combinatorial synthesis techniques, and a major b2048 to further advances in this field is access to rapid measurement of structural parameters. The specification of the beamline follows from these points. It must have a small focal spot to match closely the size of the crystals, high resolution for MAD techniques, and a high flux in the small focus. The strategy for satisfying these constraints is to us a system which is compact and which uses the minimum number of components. This is done in this case by using a pseudo channel cut crystal monochromator with tangentially bent crystals, in combination with a 1:1 focusing toroidal mirror. The toroidal mirror at 1:1 magnification has only very small aberrations, and from a 220 (h) by 25 (v) [micro] m FWHM source, an image of 220 by 45 [micro]m FWHM should be produced for a 3 mrad horizontal aperture for a full vertical aperture. This has already been achieved on an existing beamline. The crystal monochromator uses tangentially bent crystals in a concave - convex configuration to achieve matching of Bragg angles to the divergent source, while maintaining zero focusing power. A useful feature of this arrangement is that while there is an optimum crystal curvature for each energy that gives the expected Darwin width limited
Christofilos, N.C.; Polk, I.J.
1959-02-17
Improvements in linear particle accelerators are described. A drift tube system for a linear ion accelerator reduces gap capacity between adjacent drift tube ends. This is accomplished by reducing the ratio of the diameter of the drift tube to the diameter of the resonant cavity. Concentration of magnetic field intensity at the longitudinal midpoint of the external sunface of each drift tube is reduced by increasing the external drift tube diameter at the longitudinal center region.
Keawprasert, T.; Anhalt, K.; Taubert, D. R.; Sperling, A.; Schuster, M.; Nevas, S.
2013-09-11
An LP3 radiation thermometer was absolutely calibrated at a newly developed monochromator-based set-up and the TUneable Lasers in Photometry (TULIP) facility of PTB in the wavelength range from 400 nm to 1100 nm. At both facilities, the spectral radiation of the respective sources irradiates an integrating sphere, thus generating uniform radiance across its precision aperture. The spectral irradiance of the integrating sphere is determined via an effective area of a precision aperture and a Si trap detector, traceable to the primary cryogenic radiometer of PTB. Due to the limited output power from the monochromator, the absolute calibration was performed with the measurement uncertainty of 0.17 % (k= 1), while the respective uncertainty at the TULIP facility is 0.14 %. Calibration results obtained by the two facilities were compared in terms of spectral radiance responsivity, effective wavelength and integral responsivity. It was found that the measurement results in integral responsivity at the both facilities are in agreement within the expanded uncertainty (k= 2). To verify the calibration accuracy, the absolutely calibrated radiation thermometer was used to measure the thermodynamic freezing temperatures of the PTB gold fixed-point blackbody.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Linear Accelerator (LINAC) The core of the LANSCE facility is one of the nation's most powerful proton linear accelerators or LINAC. The LINAC at LANSCE has served the nation since 1972, providing the beam current required by all the experimental areas that support NNSA-DP and other DOE missions. The LINAC's capability to reliably deliver beam current is the key to the LANSCE's ability to do research-and thus the key to meeting NNSA and DOE mission deliverables. The LANSCE Accelerator The LANSCE
Colgate, S.A.
1958-05-27
An improvement is presented in linear accelerators for charged particles with respect to the stable focusing of the particle beam. The improvement consists of providing a radial electric field transverse to the accelerating electric fields and angularly introducing the beam of particles in the field. The results of the foregoing is to achieve a beam which spirals about the axis of the acceleration path. The combination of the electric fields and angular motion of the particles cooperate to provide a stable and focused particle beam.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
1.2 Print Center for X-Ray Optics Soft X-Ray Microscopy Scientific disciplines: Magnetism, spin dynamics, x-ray optics, environmental science, materials science GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics Bend magnet Energy range 500-1300 eV Monochromator Zone-plate linear Measured flux (1.9 GeV, 400 mA) Images with 1000 x 1000 pixels, 1000 photons/pixel recorded in 3 s at 517 eV with 0.2% BW Resolving power (E/ΔE) 500-700 Endstations X-ray microscope (XM-1)
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
1.2 Print Center for X-Ray Optics Soft X-Ray Microscopy Scientific disciplines: Magnetism, spin dynamics, x-ray optics, environmental science, materials science GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics Bend magnet Energy range 500-1300 eV Monochromator Zone-plate linear Measured flux (1.9 GeV, 400 mA) Images with 1000 x 1000 pixels, 1000 photons/pixel recorded in 3 s at 517 eV with 0.2% BW Resolving power (E/ΔE) 500-700 Endstations X-ray microscope (XM-1)
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Beamline 6.1.2 Print Center for X-Ray Optics Soft X-Ray Microscopy Scientific disciplines: Magnetism, spin dynamics, x-ray optics, environmental science, materials science GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics Bend magnet Energy range 500-1300 eV Monochromator Zone-plate linear Measured flux (1.9 GeV, 400 mA) Images with 1000 x 1000 pixels, 1000 photons/pixel recorded in 3 s at 517 eV with 0.2% BW Resolving power (E/ΔE) 500-700 Endstations X-ray microscope (XM-1)
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Beamline 6.1.2 Print Center for X-Ray Optics Soft X-Ray Microscopy Scientific disciplines: Magnetism, spin dynamics, x-ray optics, environmental science, materials science GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics Bend magnet Energy range 500-1300 eV Monochromator Zone-plate linear Measured flux (1.9 GeV, 400 mA) Images with 1000 x 1000 pixels, 1000 photons/pixel recorded in 3 s at 517 eV with 0.2% BW Resolving power (E/ΔE) 500-700 Endstations X-ray microscope (XM-1)
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Beamline 6.1.2 Print Center for X-Ray Optics Soft X-Ray Microscopy Scientific disciplines: Magnetism, spin dynamics, x-ray optics, environmental science, materials science GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics Bend magnet Energy range 500-1300 eV Monochromator Zone-plate linear Measured flux (1.9 GeV, 400 mA) Images with 1000 x 1000 pixels, 1000 photons/pixel recorded in 3 s at 517 eV with 0.2% BW Resolving power (E/ΔE) 500-700 Endstations X-ray microscope (XM-1)
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Beamline 6.1.2 Beamline 6.1.2 Print Tuesday, 20 October 2009 08:41 Center for X-Ray Optics Soft X-Ray Microscopy Scientific disciplines: Magnetism, spin dynamics, x-ray optics, environmental science, materials science GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics Bend magnet Energy range 500-1300 eV Monochromator Zone-plate linear Measured flux (1.9 GeV, 400 mA) Images with 1000 x 1000 pixels, 1000 photons/pixel recorded in 3 s at 517 eV with 0.2% BW Resolving power (E/ΔE)
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
1.2 Print Center for X-Ray Optics Soft X-Ray Microscopy Scientific disciplines: Magnetism, spin dynamics, x-ray optics, environmental science, materials science GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics Bend magnet Energy range 500-1300 eV Monochromator Zone-plate linear Measured flux (1.9 GeV, 400 mA) Images with 1000 x 1000 pixels, 1000 photons/pixel recorded in 3 s at 517 eV with 0.2% BW Resolving power (E/ΔE) 500-700 Endstations X-ray microscope (XM-1)
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
1.2 Print Center for X-Ray Optics Soft X-Ray Microscopy Scientific disciplines: Magnetism, spin dynamics, x-ray optics, environmental science, materials science GENERAL BEAMLINE INFORMATION Operational Yes Source characteristics Bend magnet Energy range 500-1300 eV Monochromator Zone-plate linear Measured flux (1.9 GeV, 400 mA) Images with 1000 x 1000 pixels, 1000 photons/pixel recorded in 3 s at 517 eV with 0.2% BW Resolving power (E/ΔE) 500-700 Endstations X-ray microscope (XM-1)
Sagittal focusing Laue monochromator
Zhong; Zhong , Hanson; Jonathan , Hastings; Jerome , Kao; Chi-Chang , Lenhard; Anthony , Siddons; David Peter , Zhong; Hui
2009-03-24
An x-ray focusing device generally includes a slide pivotable about a pivot point defined at a forward end thereof, a rail unit fixed with respect to the pivotable slide, a forward crystal for focusing x-rays disposed at the forward end of the pivotable slide and a rearward crystal for focusing x-rays movably coupled to the pivotable slide and the fixed rail unit at a distance rearward from the forward crystal. The forward and rearward crystals define reciprocal angles of incidence with respect to the pivot point, wherein pivoting of the slide about the pivot point changes the incidence angles of the forward and rearward crystals while simultaneously changing the distance between the forward and rearward crystals.
Seidler, G. T. Mortensen, D. R.; Remesnik, A. J.; Pacold, J. I.; Ball, N. A.; Barry, N.; Styczinski, M.; Hoidn, O. R.
2014-11-15
We report the development of a laboratory-based Rowland-circle monochromator that incorporates a low power x-ray (bremsstrahlung) tube source, a spherically bent crystal analyzer, and an energy-resolving solid-state detector. This relatively inexpensive, introductory level instrument achieves 1-eV energy resolution for photon energies of ∼5 keV to ∼10 keV while also demonstrating a net efficiency previously seen only in laboratory monochromators having much coarser energy resolution. Despite the use of only a compact, air-cooled 10 W x-ray tube, we find count rates for nonresonant x-ray emission spectroscopy comparable to those achieved at monochromatized spectroscopy beamlines at synchrotron light sources. For x-ray absorption near edge structure, the monochromatized flux is small (due to the use of a low-powered x-ray generator) but still useful for routine transmission-mode studies of concentrated samples. These results indicate that upgrading to a standard commercial high-power line-focused x-ray tube or rotating anode x-ray generator would result in monochromatized fluxes of order 10{sup 6}–10{sup 7} photons/s with no loss in energy resolution. This work establishes core technical capabilities for a rejuvenation of laboratory-based hard x-ray spectroscopies that could have special relevance for contemporary research on catalytic or electrical energy storage systems using transition-metal, lanthanide, or noble-metal active species.
Fault tolerant linear actuator
Tesar, Delbert
2004-09-14
In varying embodiments, the fault tolerant linear actuator of the present invention is a new and improved linear actuator with fault tolerance and positional control that may incorporate velocity summing, force summing, or a combination of the two. In one embodiment, the invention offers a velocity summing arrangement with a differential gear between two prime movers driving a cage, which then drives a linear spindle screw transmission. Other embodiments feature two prime movers driving separate linear spindle screw transmissions, one internal and one external, in a totally concentric and compact integrated module.
Snapshot: Linear Lamps (TLEDs)
Broader source: Energy.gov [DOE]
A report using LED Lighting Facts data to examine the current state of the market for linear fluorescent lamps. (8 pages, July 2016)
Linear phase compressive filter
McEwan, Thomas E.
1995-01-01
A phase linear filter for soliton suppression is in the form of a laddered series of stages of non-commensurate low pass filters with each low pass filter having a series coupled inductance (L) and a reverse biased, voltage dependent varactor diode, to ground which acts as a variable capacitance (C). L and C values are set to levels which correspond to a linear or conventional phase linear filter. Inductance is mapped directly from that of an equivalent nonlinear transmission line and capacitance is mapped from the linear case using a large signal equivalent of a nonlinear transmission line.
Linear phase compressive filter
McEwan, T.E.
1995-06-06
A phase linear filter for soliton suppression is in the form of a laddered series of stages of non-commensurate low pass filters with each low pass filter having a series coupled inductance (L) and a reverse biased, voltage dependent varactor diode, to ground which acts as a variable capacitance (C). L and C values are set to levels which correspond to a linear or conventional phase linear filter. Inductance is mapped directly from that of an equivalent nonlinear transmission line and capacitance is mapped from the linear case using a large signal equivalent of a nonlinear transmission line. 2 figs.
Linearly polarized fiber amplifier
Kliner, Dahv A.; Koplow, Jeffery P.
2004-11-30
Optically pumped rare-earth-doped polarizing fibers exhibit significantly higher gain for one linear polarization state than for the orthogonal state. Such a fiber can be used to construct a single-polarization fiber laser, amplifier, or amplified-spontaneous-emission (ASE) source without the need for additional optical components to obtain stable, linearly polarized operation.
Kugland, Nathan; Doeppner, Tilo; Glenzer, Siegfried; Constantin, Carmen; Niemann, Chris; Neumayer, Paul
2015-04-07
A method is provided for characterizing spectrometric properties (e.g., peak reflectivity, reflection curve width, and Bragg angle offset) of the K.alpha. emission line reflected narrowly off angle of the direct reflection of a bent crystal and in particular of a spherically bent quartz 200 crystal by analyzing the off-angle x-ray emission from a stronger emission line reflected at angles far from normal incidence. The bent quartz crystal can therefore accurately image argon K.alpha. x-rays at near-normal incidence (Bragg angle of approximately 81 degrees). The method is useful for in-situ calibration of instruments employing the crystal as a grating by first operating the crystal as a high throughput focusing monochromator on the Rowland circle at angles far from normal incidence (Bragg angle approximately 68 degrees) to make a reflection curve with the He-like x-rays such as the He-.alpha. emission line observed from a laser-excited plasma.
Bosamykin, V.S.; Pavlovskiy, A.I.
1984-03-01
A linear induction accelerator of charged particles, containing inductors and an acceleration circuit, characterized by the fact that, for the purpose of increasing the power of the accelerator, each inductor is made in the form of a toroidal line with distributed parameters, from one end of which in the gap of the line a ring commutator is included, and from the other end of the ine a resistor is hooked up, is described.
Combustion powered linear actuator
Fischer, Gary J.
2007-09-04
The present invention provides robotic vehicles having wheeled and hopping mobilities that are capable of traversing (e.g. by hopping over) obstacles that are large in size relative to the robot and, are capable of operation in unpredictable terrain over long range. The present invention further provides combustion powered linear actuators, which can include latching mechanisms to facilitate pressurized fueling of the actuators, as can be used to provide wheeled vehicles with a hopping mobility.
Buttram, M.T.; Ginn, J.W.
1988-06-21
A linear induction accelerator includes a plurality of adder cavities arranged in a series and provided in a structure which is evacuated so that a vacuum inductance is provided between each adder cavity and the structure. An energy storage system for the adder cavities includes a pulsed current source and a respective plurality of bipolar converting networks connected thereto. The bipolar high-voltage, high-repetition-rate square pulse train sets and resets the cavities. 4 figs.
Emma, P.
1995-06-01
The Stanford Linear Collider (SLC) is the first and only high-energy e{sup +}e{sup {minus}} linear collider in the world. Its most remarkable features are high intensity, submicron sized, polarized (e{sup {minus}}) beams at a single interaction point. The main challenges posed by these unique characteristics include machine-wide emittance preservation, consistent high intensity operation, polarized electron production and transport, and the achievement of a high degree of beam stability on all time scales. In addition to serving as an important machine for the study of Z{sup 0} boson production and decay using polarized beams, the SLC is also an indispensable source of hands-on experience for future linear colliders. Each new year of operation has been highlighted with a marked improvement in performance. The most significant improvements for the 1994-95 run include new low impedance vacuum chambers for the damping rings, an upgrade to the optics and diagnostics of the final focus systems, and a higher degree of polarization from the electron source. As a result, the average luminosity has nearly doubled over the previous year with peaks approaching 10{sup 30} cm{sup {minus}2}s{sup {minus}1} and an 80% electron polarization at the interaction point. These developments as well as the remaining identifiable performance limitations will be discussed.
Linear Fresnel | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Concentrating Solar Power » Linear Fresnel Linear Fresnel DOE funds solar research and development (R&D) in linear Fresnel systems as one of four CSP technologies aiming to meet the goals of the SunShot Initiative. Linear Fresnel systems, which are a type of linear concentrator, are active in Germany, Spain, Australia, India, and the United States. The SunShot Initiative funds R&D on linear Fresnel systems and related aspects within the industry, national laboratories and universities
Van Atta, C.M.; Beringer, R.; Smith, L.
1959-01-01
A linear accelerator of heavy ions is described. The basic contributions of the invention consist of a method and apparatus for obtaining high energy particles of an element with an increased charge-to-mass ratio. The method comprises the steps of ionizing the atoms of an element, accelerating the resultant ions to an energy substantially equal to one Mev per nucleon, stripping orbital electrons from the accelerated ions by passing the ions through a curtain of elemental vapor disposed transversely of the path of the ions to provide a second charge-to-mass ratio, and finally accelerating the resultant stripped ions to a final energy of at least ten Mev per nucleon.
Energy Science and Technology Software Center (OSTI)
2006-11-17
Software that simulates and inverts electromagnetic field data for subsurface electrical properties (electrical conductivity) of geological media. The software treats data produced by a time harmonic source field excitation arising from the following antenna geometery: loops and grounded bipoles, as well as point electric and magnetic dioples. The inversion process is carried out using a non-linear conjugate gradient optimization scheme, which minimizes the misfit between field data and model data using a least squares criteria.more » The software is an upgrade from the code NLCGCS_MP ver 1.0. The upgrade includes the following components: Incorporation of new 1 D field sourcing routines to more accurately simulate the 3D electromagnetic field for arbitrary geologic& media, treatment for generalized finite length transmitting antenna geometry (antennas with vertical and horizontal component directions). In addition, the software has been upgraded to treat transverse anisotropy in electrical conductivity.« less
Positrons for linear colliders
Ecklund, S.
1987-11-01
The requirements of a positron source for a linear collider are briefly reviewed, followed by methods of positron production and production of photons by electromagnetic cascade showers. Cross sections for the electromagnetic cascade shower processes of positron-electron pair production and Compton scattering are compared. A program used for Monte Carlo analysis of electromagnetic cascades is briefly discussed, and positron distributions obtained from several runs of the program are discussed. Photons from synchrotron radiation and from channeling are also mentioned briefly, as well as positron collection, transverse focusing techniques, and longitudinal capture. Computer ray tracing is then briefly discussed, followed by space-charge effects and thermal heating and stress due to showers. (LEW)
History of Proton Linear Accelerators
DOE R&D Accomplishments [OSTI]
Alvarez, L. W.
1987-01-01
Some personal recollections are presented that relate to the author`s experience developing linear accelerators, particularly for protons. (LEW)
Kliman, G.B.; Brynsvold, G.V.; Jahns, T.M.
1989-08-22
A winding and method of winding for a submersible linear pump for pumping liquid sodium are disclosed. The pump includes a stator having a central cylindrical duct preferably vertically aligned. The central vertical duct is surrounded by a system of coils in slots. These slots are interleaved with magnetic flux conducting elements, these magnetic flux conducting elements forming a continuous magnetic field conduction path along the stator. The central duct has placed therein a cylindrical magnetic conducting core, this core having a cylindrical diameter less than the diameter of the cylindrical duct. The core once placed to the duct defines a cylindrical interstitial pumping volume of the pump. This cylindrical interstitial pumping volume preferably defines an inlet at the bottom of the pump, and an outlet at the top of the pump. Pump operation occurs by static windings in the outer stator sequentially conveying toroidal fields from the pump inlet at the bottom of the pump to the pump outlet at the top of the pump. The winding apparatus and method of winding disclosed uses multiple slots per pole per phase with parallel winding legs on each phase equal to or less than the number of slots per pole per phase. The slot sequence per pole per phase is chosen to equalize the variations in flux density of the pump sodium as it passes into the pump at the pump inlet with little or no flux and acquires magnetic flux in passage through the pump to the pump outlet. 4 figs.
Kliman, Gerald B.; Brynsvold, Glen V.; Jahns, Thomas M.
1989-01-01
A winding and method of winding for a submersible linear pump for pumping liquid sodium is disclosed. The pump includes a stator having a central cylindrical duct preferably vertically aligned. The central vertical duct is surrounded by a system of coils in slots. These slots are interleaved with magnetic flux conducting elements, these magnetic flux conducting elements forming a continuous magnetic field conduction path along the stator. The central duct has placed therein a cylindrical magnetic conducting core, this core having a cylindrical diameter less than the diameter of the cylindrical duct. The core once placed to the duct defines a cylindrical interstitial pumping volume of the pump. This cylindrical interstitial pumping volume preferably defines an inlet at the bottom of the pump, and an outlet at the top of the pump. Pump operation occurs by static windings in the outer stator sequentially conveying toroidal fields from the pump inlet at the bottom of the pump to the pump outlet at the top of the pump. The winding apparatus and method of winding disclosed uses multiple slots per pole per phase with parallel winding legs on each phase equal to or less than the number of slots per pole per phase. The slot sequence per pole per phase is chosen to equalize the variations in flux density of the pump sodium as it passes into the pump at the pump inlet with little or no flux and acquires magnetic flux in passage through the pump to the pump outlet.
Meisner, John W.; Moore, Robert M.; Bienvenue, Louis L.
1985-03-19
Electromagnetic linear induction pump for liquid metal which includes a unitary pump duct. The duct comprises two substantially flat parallel spaced-apart wall members, one being located above the other and two parallel opposing side members interconnecting the wall members. Located within the duct are a plurality of web members interconnecting the wall members and extending parallel to the side members whereby the wall members, side members and web members define a plurality of fluid passageways, each of the fluid passageways having substantially the same cross-sectional flow area. Attached to an outer surface of each side member is an electrically conductive end bar for the passage of an induced current therethrough. A multi-phase, electrical stator is located adjacent each of the wall members. The duct, stators, and end bars are enclosed in a housing which is provided with an inlet and outlet in fluid communication with opposite ends of the fluid passageways in the pump duct. In accordance with a preferred embodiment, the inlet and outlet includes a transition means which provides for a transition from a round cross-sectional flow path to a substantially rectangular cross-sectional flow path defined by the pump duct.
New Zone Plate for Soft X-Ray Microscopy at 15-nm Spatial Resolution
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
DEPARTMENT OF ENERGY HYBRID ELECTRIC TRANSIT BUS EVALUATIONS The role of AVTA is to bridge the gap between R&D and commercial availability of advanced vehicle technologies that reduce U.S. petroleum use while improving air quality. AVTA supports the U.S. Department of Energy's FreedomCAR and Vehicle Technologies Program in moving these technologies from R&D to market deployment by examining market factors and customer requirements, evaluating performance and durability of alternative
The TESLA superconducting linear collider
the TESLA Collaboration
1997-03-01
This paper summarizes the present status of the studies for a superconducting Linear Collider (TESLA). {copyright} {ital 1997 American Institute of Physics.}
Acoustic emission linear pulse holography
Collins, H.D.; Busse, L.J.; Lemon, D.K.
1983-10-25
This device relates to the concept of and means for performing Acoustic Emission Linear Pulse Holography, which combines the advantages of linear holographic imaging and Acoustic Emission into a single non-destructive inspection system. This unique system produces a chronological, linear holographic image of a flaw by utilizing the acoustic energy emitted during crack growth. The innovation is the concept of utilizing the crack-generated acoustic emission energy to generate a chronological series of images of a growing crack by applying linear, pulse holographic processing to the acoustic emission data. The process is implemented by placing on a structure an array of piezoelectric sensors (typically 16 or 32 of them) near the defect location. A reference sensor is placed between the defect and the array.
Linear Accelerator | Advanced Photon Source
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Linear Accelerator Producing brilliant x-ray beams at the APS begins with electrons emitted from a cathode heated to 1100 C. The electrons are accelerated by high-voltage...
Belos Block Linear Solvers Package
Energy Science and Technology Software Center (OSTI)
2004-03-01
Belos is an extensible and interoperable framework for large-scale, iterative methods for solving systems of linear equations with multiple right-hand sides. The motivation for this framework is to provide a generic interface to a collection of algorithms for solving large-scale linear systems. Belos is interoperable because both the matrix and vectors are considered to be opaque objects--only knowledge of the matrix and vectors via elementary operations is necessary. An implementation of Balos is accomplished viamore » the use of interfaces. One of the goals of Belos is to allow the user flexibility in specifying the data representation for the matrix and vectors and so leverage any existing software investment. The algorithms that will be included in package are Krylov-based linear solvers, like Block GMRES (Generalized Minimal RESidual) and Block CG (Conjugate-Gradient).« less
Henry, J.J.
1961-09-01
A linear count-rate meter is designed to provide a highly linear output while receiving counting rates from one cycle per second to 100,000 cycles per second. Input pulses enter a linear discriminator and then are fed to a trigger circuit which produces positive pulses of uniform width and amplitude. The trigger circuit is connected to a one-shot multivibrator. The multivibrator output pulses have a selected width. Feedback means are provided for preventing transistor saturation in the multivibrator which improves the rise and decay times of the output pulses. The multivibrator is connected to a diode-switched, constant current metering circuit. A selected constant current is switched to an averaging circuit for each pulse received, and for a time determined by the received pulse width. The average output meter current is proportional to the product of the counting rate, the constant current, and the multivibrator output pulse width.
Linear Fresnel Power Plant Illustration
Broader source: Energy.gov [DOE]
With this concentrating solar power (CSP) graphic, flat or slightly curved mirrors mounted on trackers on the ground are configured to reflect sunlight onto a receiver tube fixed in space above these mirrors. A small parabolic mirror is sometimes added atop the receiver to further focus the sunlight. Linear CSP collectors capture the sun's energy with large mirrors that reflect and focus the sunlight onto a linear receiver tube. The receiver contains a fluid that is heated by the sunlight and then used to create superheated steam that spins a turbine that drives a generator to produce electricity.
Linear electric field mass spectrometry
McComas, D.J.; Nordholt, J.E.
1992-12-01
A mass spectrometer and methods for mass spectrometry are described. The apparatus is compact and of low weight and has a low power requirement, making it suitable for use on a space satellite and as a portable detector for the presence of substances. High mass resolution measurements are made by timing ions moving through a gridless cylindrically symmetric linear electric field. 8 figs.
Linear electric field mass spectrometry
McComas, David J.; Nordholt, Jane E.
1992-01-01
A mass spectrometer and methods for mass spectrometry. The apparatus is compact and of low weight and has a low power requirement, making it suitable for use on a space satellite and as a portable detector for the presence of substances. High mass resolution measurements are made by timing ions moving through a gridless cylindrically symmetric linear electric field.
International Linear Collider Technical Design Report - Volume...
Office of Scientific and Technical Information (OSTI)
International Linear Collider Technical Design Report - Volume 2: Physics Citation Details In-Document Search Title: International Linear Collider Technical Design Report - Volume ...
Cast dielectric composite linear accelerator
Sanders, David M.; Sampayan, Stephen; Slenes, Kirk; Stoller, H. M.
2009-11-10
A linear accelerator having cast dielectric composite layers integrally formed with conductor electrodes in a solventless fabrication process, with the cast dielectric composite preferably having a nanoparticle filler in an organic polymer such as a thermosetting resin. By incorporating this cast dielectric composite the dielectric constant of critical insulating layers of the transmission lines of the accelerator are increased while simultaneously maintaining high dielectric strengths for the accelerator.
Segmented rail linear induction motor
Cowan, M. Jr.; Marder, B.M.
1996-09-03
A segmented rail linear induction motor has a segmented rail consisting of a plurality of nonferrous electrically conductive segments aligned along a guideway. The motor further includes a carriage including at least one pair of opposed coils fastened to the carriage for moving the carriage. A power source applies an electric current to the coils to induce currents in the conductive surfaces to repel the coils from adjacent edges of the conductive surfaces. 6 figs.
Segmented rail linear induction motor
Cowan, Jr., Maynard; Marder, Barry M.
1996-01-01
A segmented rail linear induction motor has a segmented rail consisting of a plurality of nonferrous electrically conductive segments aligned along a guideway. The motor further includes a carriage including at least one pair of opposed coils fastened to the carriage for moving the carriage. A power source applies an electric current to the coils to induce currents in the conductive surfaces to repel the coils from adjacent edges of the conductive surfaces.
Precision linear ramp function generator
Jatko, W. Bruce (Knoxville, TN); McNeilly, David R. (Maryville, TN); Thacker, Louis H. (Knoxville, TN)
1986-01-01
A ramp function generator is provided which produces a precise linear ramp unction which is repeatable and highly stable. A derivative feedback loop is used to stabilize the output of an integrator in the forward loop and control the ramp rate. The ramp may be started from a selected baseline voltage level and the desired ramp rate is selected by applying an appropriate constant voltage to the input of the integrator.
Precision linear ramp function generator
Jatko, W.B.; McNeilly, D.R.; Thacker, L.H.
1984-08-01
A ramp function generator is provided which produces a precise linear ramp function which is repeatable and highly stable. A derivative feedback loop is used to stabilize the output of an integrator in the forward loop and control the ramp rate. The ramp may be started from a selected baseline voltage level and the desired ramp rate is selected by applying an appropriate constant voltage to the input of the integrator.
Acoustic emission linear pulse holography
Collins, H. Dale; Busse, Lawrence J.; Lemon, Douglas K.
1985-01-01
Defects in a structure are imaged as they propagate, using their emitted acoustic energy as a monitored source. Short bursts of acoustic energy propagate through the structure to a discrete element receiver array. A reference timing transducer located between the array and the inspection zone initiates a series of time-of-flight measurements. A resulting series of time-of-flight measurements are then treated as aperture data and are transferred to a computer for reconstruction of a synthetic linear holographic image. The images can be displayed and stored as a record of defect growth.
Nonferromagnetic linear variable differential transformer
Ellis, James F.; Walstrom, Peter L.
1977-06-14
A nonferromagnetic linear variable differential transformer for accurately measuring mechanical displacements in the presence of high magnetic fields is provided. The device utilizes a movable primary coil inside a fixed secondary coil that consists of two series-opposed windings. Operation is such that the secondary output voltage is maintained in phase (depending on polarity) with the primary voltage. The transducer is well-suited to long cable runs and is useful for measuring small displacements in the presence of high or alternating magnetic fields.
Reticle stage based linear dosimeter
Berger, Kurt W.
2007-03-27
A detector to measure EUV intensity employs a linear array of photodiodes. The detector is particularly suited for photolithography systems that includes: (i) a ringfield camera; (ii) a source of radiation; (iii) a condenser for processing radiation from the source of radiation to produce a ringfield illumination field for illuminating a mask; (iv) a reticle that is positioned at the ringfield camera's object plane and from which a reticle image in the form of an intensity profile is reflected into the entrance pupil of the ringfield camera, wherein the reticle moves in a direction that is transverse to the length of the ringfield illumination field that illuminates the reticle; (v) detector for measuring the entire intensity along the length of the ringfield illumination field that is projected onto the reticle; and (vi) a wafer onto which the reticle imaged is projected from the ringfield camera.
Reticle stage based linear dosimeter
Berger, Kurt W.
2005-06-14
A detector to measure EUV intensity employs a linear array of photodiodes. The detector is particularly suited for photolithography systems that includes: (i) a ringfield camera; (ii) a source of radiation; (iii) a condenser for processing radiation from the source of radiation to produce a ringfield illumination field for illuminating a mask; (iv) a reticle that is positioned at the ringfield camera's object plane and from which a reticle image in the form of an intensity profile is reflected into the entrance pupil of the ringfield camera, wherein the reticle moves in a direction that is transverse to the length of the ringfield illumination field that illuminates the reticle; (v) detector for measuring the entire intensity along the length of the ringfield illumination field that is projected onto the reticle; and (vi) a wafer onto which the reticle imaged is projected from the ringfield camera.
PC Basic Linear Algebra Subroutines
Energy Science and Technology Software Center (OSTI)
1992-03-09
PC-BLAS is a highly optimized version of the Basic Linear Algebra Subprograms (BLAS), a standardized set of thirty-eight routines that perform low-level operations on vectors of numbers in single and double-precision real and complex arithmetic. Routines are included to find the index of the largest component of a vector, apply a Givens or modified Givens rotation, multiply a vector by a constant, determine the Euclidean length, perform a dot product, swap and copy vectors, andmore » find the norm of a vector. The BLAS have been carefully written to minimize numerical problems such as loss of precision and underflow and are designed so that the computation is independent of the interface with the calling program. This independence is achieved through judicious use of Assembly language macros. Interfaces are provided for Lahey Fortran 77, Microsoft Fortran 77, and Ryan-McFarland IBM Professional Fortran.« less
Linear induction accelerator parameter options
Birx, D.L.; Caporaso, G.J.; Reginato, L.L.
1986-04-21
The principal undertaking of the Beam Research Program over the past decade has been the investigation of propagating intense self-focused beams. Recently, the major activity of the program has shifted toward the investigation of converting high quality electron beams directly to laser radiation. During the early years of the program, accelerator development was directed toward the generation of very high current (>10 kA), high energy beams (>50 MeV). In its new mission, the program has shifted the emphasis toward the production of lower current beams (>3 kA) with high brightness (>10/sup 6/ A/(rad-cm)/sup 2/) at very high average power levels. In efforts to produce these intense beams, the state of the art of linear induction accelerators (LIA) has been advanced to the point of satisfying not only the current requirements but also future national needs.
High Performance Preconditioners and Linear Solvers
Energy Science and Technology Software Center (OSTI)
2006-07-27
Hypre is a software library focused on the solution of large, sparse linear systems of equations on massively parallel computers.
Two-axis sagittal focusing monochromator
Haas, Edwin G; Stelmach, Christopher; Zhong, Zhong
2014-05-13
An x-ray focusing device and method for adjustably focusing x-rays in two orthogonal directions simultaneously. The device and method can be operated remotely using two pairs of orthogonal benders mounted on a rigid, open frame such that x-rays may pass through the opening in the frame. The added x-ray flux allows significantly higher brightness from the same x-ray source.
Multiple wavelength X-ray monochromators
Steinmeyer, P.A.
1992-11-17
An improved apparatus and method is provided for separating input x-ray radiation containing first and second x-ray wavelengths into spatially separate first and second output radiation which contain the first and second x-ray wavelengths, respectively. The apparatus includes a crystalline diffractor which includes a first set of parallel crystal planes, where each of the planes is spaced a predetermined first distance from one another. The crystalline diffractor also includes a second set of parallel crystal planes inclined at an angle with respect to the first set of crystal planes where each of the planes of the second set of parallel crystal planes is spaced a predetermined second distance from one another. In one embodiment, the crystalline diffractor is comprised of a single crystal. In a second embodiment, the crystalline diffractor is comprised of a stack of two crystals. In a third embodiment, the crystalline diffractor includes a single crystal that is bent for focusing the separate first and second output x-ray radiation wavelengths into separate focal points. 3 figs.
Multiple wavelength X-ray monochromators
Steinmeyer, Peter A.
1992-11-17
An improved apparatus and method is provided for separating input x-ray radiation containing first and second x-ray wavelengths into spatially separate first and second output radiation which contain the first and second x-ray wavelengths, respectively. The apparatus includes a crystalline diffractor which includes a first set of parallel crystal planes, where each of the planes is spaced a predetermined first distance from one another. The crystalline diffractor also includes a second set of parallel crystal planes inclined at an angle with respect to the first set of crystal planes where each of the planes of the second set of parallel crystal planes is spaced a predetermined second distance from one another. In one embodiment, the crystalline diffractor is comprised of a single crystal. In a second embodiment, the crystalline diffractor is comprised of a stack of two crystals. In a third embodiment, the crystalline diffractor includes a single crystal that is bent for focussing the separate first and second output x-ray radiation wavelengths into separate focal points.
International Workshop on Linear Colliders 2010
None
2011-10-06
IWLC2010 International Workshop on Linear Colliders 2010ECFA-CLIC-ILC joint meeting: Monday 18 October - Friday 22 October 2010Venue: CERN and CICG (International Conference Centre Geneva, Switzerland)This year, the International Workshop on Linear Colliders organized by the European Committee for Future Accelerators (ECFA) will study the physics, detectors and accelerator complex of a linear collider covering both CLIC and ILC options.Contact Workshop SecretariatIWLC2010 is hostedby CERN
International Workshop on Linear Colliders 2010
None
2011-10-06
IWLC2010 International Workshop on Linear Colliders 2010ECFA-CLIC-ILC joint meeting: Monday 18 October - Friday 22 October 2010Venue: CERN and CICG (International Conference Centre Geneva, Switzerland) This year, the International Workshop on Linear Colliders organized by the European Committee for Future Accelerators (ECFA) will study the physics, detectors and accelerator complex of a linear collider covering both CLIC and ILC options.Contact Workshop Secretariat IWLC2010 is hosted by CERN
Independent Oversight Inspection, Stanford Linear Accelerator...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Safety, and Health Programs at the Stanford Linear Accelerator Center This report provides the results of an inspection of the environment, safety, and health programs at the ...
International Linear Collider Technical Design Report - Volume...
Office of Scientific and Technical Information (OSTI)
Linear Collider Technical Design Report - Volume 2: Physics Baer, Howard; Barklow, Tim; Fujii, Keisuke; Gao, Yuanning; Hoang, Andre; Kanemura, Shinya; List, Jenny; Logan, Heather...
LED Replacements for Linear Fluorescent Lamps Webcast
Broader source: Energy.gov [DOE]
In this June 20, 2011 webcast on LED products marketed as replacements for linear fluorescent lamps, Jason Tuenge of the Pacific Northwest National Laboratory (PNNL) discussed current Lighting...
Linear Thermite Charge - Energy Innovation Portal
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
The Linear Thermite Charge (LTC) is designed to rapidly cut through concrete and steel ... Can cut both concrete and steel at one time making rebarconcrete structural elements ...
International Linear Collider Technical Design Report - Volume...
Office of Scientific and Technical Information (OSTI)
Design Report - Volume 2: Physics Citation Details In-Document Search Title: International Linear Collider Technical Design Report - Volume 2: Physics You are accessing a ...
Ultra-high vacuum photoelectron linear accelerator
Yu, David U.L.; Luo, Yan
2013-07-16
An rf linear accelerator for producing an electron beam. The outer wall of the rf cavity of said linear accelerator being perforated to allow gas inside said rf cavity to flow to a pressure chamber surrounding said rf cavity and having means of ultra high vacuum pumping of the cathode of said rf linear accelerator. Said rf linear accelerator is used to accelerate polarized or unpolarized electrons produced by a photocathode, or to accelerate thermally heated electrons produced by a thermionic cathode, or to accelerate rf heated field emission electrons produced by a field emission cathode.
Automating linear accelerator quality assurance
Eckhause, Tobias; Thorwarth, Ryan; Moran, Jean M.; Al-Hallaq, Hania; Farrey, Karl; Ritter, Timothy; DeMarco, John; Pawlicki, Todd; Kim, Gwe-Ya; Popple, Richard; Sharma, Vijeshwar; Park, SungYong; Perez, Mario; Booth, Jeremy T.
2015-10-15
Purpose: The purpose of this study was 2-fold. One purpose was to develop an automated, streamlined quality assurance (QA) program for use by multiple centers. The second purpose was to evaluate machine performance over time for multiple centers using linear accelerator (Linac) log files and electronic portal images. The authors sought to evaluate variations in Linac performance to establish as a reference for other centers. Methods: The authors developed analytical software tools for a QA program using both log files and electronic portal imaging device (EPID) measurements. The first tool is a general analysis tool which can read and visually represent data in the log file. This tool, which can be used to automatically analyze patient treatment or QA log files, examines the files for Linac deviations which exceed thresholds. The second set of tools consists of a test suite of QA fields, a standard phantom, and software to collect information from the log files on deviations from the expected values. The test suite was designed to focus on the mechanical tests of the Linac to include jaw, MLC, and collimator positions during static, IMRT, and volumetric modulated arc therapy delivery. A consortium of eight institutions delivered the test suite at monthly or weekly intervals on each Linac using a standard phantom. The behavior of various components was analyzed for eight TrueBeam Linacs. Results: For the EPID and trajectory log file analysis, all observed deviations which exceeded established thresholds for Linac behavior resulted in a beam hold off. In the absence of an interlock-triggering event, the maximum observed log file deviations between the expected and actual component positions (such as MLC leaves) varied from less than 1% to 26% of published tolerance thresholds. The maximum and standard deviations of the variations due to gantry sag, collimator angle, jaw position, and MLC positions are presented. Gantry sag among Linacs was 0.336 ± 0.072 mm. The
Non-Linear Seismic Soil Structure Interaction (SSI) Method for...
Office of Environmental Management (EM)
Non-Linear Seismic Soil Structure Interaction (SSI) Method for Developing Non-Linear Seismic SSI Analysis Techniques Non-Linear Seismic Soil Structure Interaction (SSI) Method for ...
Non-linear Seismic Soil Structure Interaction Method for Developing...
Office of Environmental Management (EM)
Non-Linearity in Seismic SSI Analysis Commercial Software Elements Commercial Software Non-Linear Constitutive Models Non-Linear Seismic SSI Damping ...
Voltage regulation in linear induction accelerators
Parsons, William M.
1992-01-01
Improvement in voltage regulation in a Linear Induction Accelerator wherein a varistor, such as a metal oxide varistor, is placed in parallel with the beam accelerating cavity and the magnetic core. The non-linear properties of the varistor result in a more stable voltage across the beam accelerating cavity than with a conventional compensating resistance.
Voltage regulation in linear induction accelerators
Parsons, W.M.
1992-12-29
Improvement in voltage regulation in a linear induction accelerator wherein a varistor, such as a metal oxide varistor, is placed in parallel with the beam accelerating cavity and the magnetic core is disclosed. The non-linear properties of the varistor result in a more stable voltage across the beam accelerating cavity than with a conventional compensating resistance. 4 figs.
Optically isolated signal coupler with linear response
Kronberg, James W.
1994-01-01
An optocoupler for isolating electrical signals that translates an electrical input signal linearly to an electrical output signal. The optocoupler comprises a light emitter, a light receiver, and a light transmitting medium. The light emitter, preferably a blue, silicon carbide LED, is of the type that provides linear, electro-optical conversion of electrical signals within a narrow wavelength range. Correspondingly, the light receiver, which converts light signals to electrical signals and is preferably a cadmium sulfide photoconductor, is linearly responsive to light signals within substantially the same wavelength range as the blue LED.
Status of the SLC (Stanford Linear Collider)
Coupal, D.P.
1989-07-01
This report presents a brief review of the status of the Stanford Linear Collider. Topics covered are: Beam luminosity, Detectors and backgrounds; and Future prospects. 3 refs., 8 figs., 1 tab. (LSP)
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
9.0.1 Print Diffraction Microscopy Scientific disciplines: Applied science, biology, polymers, soft materials. Endstations: Serial crystallography Diffractive imaging Nanosurveyor GENERAL BEAMLINE INFORMATION Operational Yes. Source characteristics 10-cm period undulator (U10) Energy range 500-1500 eV Monochromator Either none or an off-axis zone-plate monochromator that will provide a focused beam with bandwidth of about 0.1% Calculated flux (1.9 GeV, 400 mA) 2.8 x 1015 photons/s/1%BW/central
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
1 Print Diffraction Microscopy Scientific disciplines: Applied science, biology, polymers, soft materials. Endstations: Serial crystallography Diffractive imaging Nanosurveyor GENERAL BEAMLINE INFORMATION Operational Yes. Source characteristics 10-cm period undulator (U10) Energy range 500-1500 eV Monochromator Either none or an off-axis zone-plate monochromator that will provide a focused beam with bandwidth of about 0.1% Calculated flux (1.9 GeV, 400 mA) 2.8 x 1015 photons/s/1%BW/central cone
Dual-range linearized transimpedance amplifier system
Wessendorf, Kurt O.
2010-11-02
A transimpedance amplifier system is disclosed which simultaneously generates a low-gain output signal and a high-gain output signal from an input current signal using a single transimpedance amplifier having two different feedback loops with different amplification factors to generate two different output voltage signals. One of the feedback loops includes a resistor, and the other feedback loop includes another resistor in series with one or more diodes. The transimpedance amplifier system includes a signal linearizer to linearize one or both of the low- and high-gain output signals by scaling and adding the two output voltage signals from the transimpedance amplifier. The signal linearizer can be formed either as an analog device using one or two summing amplifiers, or alternately can be formed as a digital device using two analog-to-digital converters and a digital signal processor (e.g. a microprocessor or a computer).
Linear transformer driver for pulse generation
Kim, Alexander A; Mazarakis, Michael G; Sinebryukhov, Vadim A; Volkov, Sergey N; Kondratiev, Sergey S; Alexeenko, Vitaly M; Bayol, Frederic; Demol, Gauthier; Stygar, William A
2015-04-07
A linear transformer driver includes at least one ferrite ring positioned to accept a load. The linear transformer driver also includes a first power delivery module that includes a first charge storage devices and a first switch. The first power delivery module sends a first energy in the form of a first pulse to the load. The linear transformer driver also includes a second power delivery module including a second charge storage device and a second switch. The second power delivery module sends a second energy in the form of a second pulse to the load. The second pulse has a frequency that is approximately three times the frequency of the first pulse. The at least one ferrite ring is positioned to force the first pulse and the second pulse to the load by temporarily isolating the first pulse and the second pulse from an electrical ground.
Linear Transformation Method for Multinuclide Decay Calculation
Ding Yuan
2010-12-29
A linear transformation method for generic multinuclide decay calculations is presented together with its properties and implications. The method takes advantage of the linear form of the decay solution N(t) = F(t)N{sub 0}, where N(t) is a column vector that represents the numbers of atoms of the radioactive nuclides in the decay chain, N{sub 0} is the initial value vector of N(t), and F(t) is a lower triangular matrix whose time-dependent elements are independent of the initial values of the system.
Linear and angular retroreflecting interferometric alignment target
Maxey, L. Curtis
2001-01-01
The present invention provides a method and apparatus for measuring both the linear displacement and angular displacement of an object using a linear interferometer system and an optical target comprising a lens, a reflective surface and a retroreflector. The lens, reflecting surface and retroreflector are specifically aligned and fixed in optical connection with one another, creating a single optical target which moves as a unit that provides multi-axis displacement information for the object with which it is associated. This displacement information is useful in many applications including machine tool control systems and laser tracker systems, among others.
Linear Concentrator Solar Power Plant Illustration
Broader source: Energy.gov [DOE]
This graphic illustrates linear concentrating solar power (CSP) collectors that capture the sun's energy with large mirrors that reflect and focus the sunlight onto a linear receiver tube. The receiver contains a fluid that is heated by the sunlight and then used to create superheated steam that spins a turbine that drives a generator to produce electricity. Alternatively, steam can be generated directly in the solar field, eliminating the need for costly heat exchangers. In a parabolic trough system, the receiver tube is positioned along the focal line of each parabola-shaped reflector.
Beamstrahlung spectra in next generation linear colliders
Barklow, T.; Chen, P. ); Kozanecki, W. )
1992-04-01
For the next generation of linear colliders, the energy loss due to beamstrahlung during the collision of the e{sup +}e{sup {minus}} beams is expected to substantially influence the effective center-of-mass energy distribution of the colliding particles. In this paper, we first derive analytical formulae for the electron and photon energy spectra under multiple beamstrahlung processes, and for the e{sup +}e{sup {minus}} and {gamma}{gamma} differential luminosities. We then apply our formulation to various classes of 500 GeV e{sup +}e{sup {minus}} linear collider designs currently under study.
KLU2 Direct Linear Solver Package
Energy Science and Technology Software Center (OSTI)
2012-01-04
KLU2 is a direct sparse solver for solving unsymmetric linear systems. It is related to the existing KLU solver, (in Amesos package and also as a stand-alone package from University of Florida) but provides template support for scalar and ordinal types. It uses a left looking LU factorization method.
Physics Case for the International Linear Collider
Fujii, Keisuke; Grojean, Christophe; Peskin, Michael E.; Barklow, Tim; Gao, Yuanning; Kanemura, Shinya; Kim, Hyungdo; List, Jenny; Nojiri, Mihoko; Perelstein, Maxim; Poeschl, Roman; Reuter, Juergen; Simon, Frank; Tanabe, Tomohiko; Yu, Jaehoon; Wells, James D.; Murayama, Hitoshi; Yamamoto, Hitoshi; /Tohoku U.
2015-06-23
We summarize the physics case for the International Linear Collider (ILC). We review the key motivations for the ILC presented in the literature, updating the projected measurement uncertainties for the ILC experiments in accord with the expected schedule of operation of the accelerator and the results of the most recent simulation studies.
Notes on beam dynamics in linear accelerators
Gluckstern, R.L.
1980-09-01
A collection of notes, on various aspects of beam dynamics in linear accelerators, which were produced by the author during five years (1975 to 1980) of consultation for the LASL Accelerator Technology (AT) Division and Medium-Energy Physics (MP) Division is presented.
A microcomputer-controlled linear heater
Schuck, V.; Rahimi, S. )
1991-10-01
In this note the circuits and principles of operation of a relatively simple and inexpensive linear temperature ramp generator are described. The upper-temperature limit and the heating rate are controlled by an Apple II microcomputer. The temperature versus time is displayed on the screen and may be plotted by an {ital x}-{ital y} plotter.
Finite Element Interface to Linear Solvers
Energy Science and Technology Software Center (OSTI)
2005-03-18
Sparse systems of linear equations arise in many engineering applications, including finite elements, finite volumes, and others. The solution of linear systems is often the most computationally intensive portion of the application. Depending on the complexity of problems addressed by the application, there may be no single solver capable of solving all of the linear systems that arise. This motivates the desire to switch an application from one solver librwy to another, depending on themore » problem being solved. The interfaces provided by solver libraries differ greatly, making it difficult to switch an application code from one library to another. The amount of library-specific code in an application Can be greatly reduced by having an abstraction layer between solver libraries and the application, putting a common "face" on various solver libraries. One such abstraction layer is the Finite Element Interface to Linear Solvers (EEl), which has seen significant use by finite element applications at Sandia National Laboratories and Lawrence Livermore National Laboratory.« less
Linear and non-linear forced response of a conical, ducted, laminar premixed flame
Karimi, Nader; Brear, Michael J.; Jin, Seong-Ho; Monty, Jason P. [Department of Mechanical Engineering, University of Melbourne, Parkville, 3010 Vic. (Australia)
2009-11-15
This paper presents an experimental study on the dynamics of a ducted, conical, laminar premixed flame subjected to acoustic excitation of varying amplitudes. The flame transfer function is measured over a range of forcing frequencies and equivalence ratios. In keeping with previous works, the measured flame transfer function is in good agreement with that predicted by linear kinematic theory at low amplitudes of acoustic velocity excitation. However, a systematic departure from linear behaviour is observed as the amplitude of the velocity forcing upstream of the flame increases. This non-linearity is mostly in the phase of the transfer function and manifests itself as a roughly constant phase at high forcing amplitude. Nonetheless, as predicted by non-linear kinematic arguments, the response always remains close to linear at low forcing frequencies, regardless of the forcing amplitude. The origin of this phase behaviour is then sought through optical data post-processing. (author)
Toward portable programming of numerical linear algebra on manycore...
Office of Scientific and Technical Information (OSTI)
Toward portable programming of numerical linear algebra on manycore nodes. Citation Details In-Document Search Title: Toward portable programming of numerical linear algebra on ...
Neutrino mass, dark energy, and the linear growth factor (Journal...
Office of Scientific and Technical Information (OSTI)
dark energy, and the linear growth factor Citation Details In-Document Search Title: Neutrino mass, dark energy, and the linear growth factor We study the degeneracies between ...
Updates to the International Linear Collider Damping Rings Baseline...
Office of Scientific and Technical Information (OSTI)
Updates to the International Linear Collider Damping Rings Baseline Design Citation Details In-Document Search Title: Updates to the International Linear Collider Damping Rings...
International Linear Collider-A Technical Progress Report (Technical...
Office of Scientific and Technical Information (OSTI)
Technical Report: International Linear Collider-A Technical Progress Report Citation Details In-Document Search Title: International Linear Collider-A Technical Progress Report The ...
A Linear Theory of Microwave Instability in Electron Storage...
Office of Scientific and Technical Information (OSTI)
Journal Article: A Linear Theory of Microwave Instability in Electron Storage Rings Citation Details In-Document Search Title: A Linear Theory of Microwave Instability in Electron...
MHK Technologies/Ocean Current Linear Turbine | Open Energy Informatio...
Current Linear Turbine < MHK Technologies Jump to: navigation, search << Return to the MHK database homepage Ocean Current Linear Turbine.jpg Technology Profile Primary...
Broader source: Energy.gov [DOE]
Non-Linear Seismic Soil Structure Interaction (SSI) Method for Developing Non-Linear Seismic SSI Analysis Techniques Justin Coleman, P.E. October 25th, 2011
Enhanced dielectric-wall linear accelerator
Sampayan, S.E.; Caporaso, G.J.; Kirbie, H.C.
1998-09-22
A dielectric-wall linear accelerator is enhanced by a high-voltage, fast e-time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators. A high voltage is placed between the electrodes sufficient to stress the voltage breakdown of the insulator on command. A light trigger, such as a laser, is focused along at least one line along the edge surface of the laminated alternating layers of isolated conductors and insulators extending between the electrodes. The laser is energized to initiate a surface breakdown by a fluence of photons, thus causing the electrical switch to close very promptly. Such insulators and lasers are incorporated in a dielectric wall linear accelerator with Blumlein modules, and phasing is controlled by adjusting the length of fiber optic cables that carry the laser light to the insulator surface. 6 figs.
Noise in phase-preserving linear amplifiers
Pandey, Shashank; Jiang, Zhang; Combes, Joshua; Caves, Carlton M.
2014-12-04
The purpose of a phase-preserving linear amplifier is to make a small signal larger, so that it can be perceived by instruments incapable of resolving the original signal, while sacrificing as little as possible in signal-to-noise. Quantum mechanics limits how well this can be done: the noise added by the amplifier, referred to the input, must be at least half a quantum at the operating frequency. This well-known quantum limit only constrains the second moments of the added noise. Here we provide the quantum constraints on the entire distribution of added noise: any phasepreserving linear amplifier is equivalent to a parametric amplifier with a physical state ? for the ancillary mode; ? determines the properties of the added noise.
Enhanced dielectric-wall linear accelerator
Sampayan, Stephen E.; Caporaso, George J.; Kirbie, Hugh C.
1998-01-01
A dielectric-wall linear accelerator is enhanced by a high-voltage, fast e-time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators. A high voltage is placed between the electrodes sufficient to stress the voltage breakdown of the insulator on command. A light trigger, such as a laser, is focused along at least one line along the edge surface of the laminated alternating layers of isolated conductors and insulators extending between the electrodes. The laser is energized to initiate a surface breakdown by a fluence of photons, thus causing the electrical switch to close very promptly. Such insulators and lasers are incorporated in a dielectric wall linear accelerator with Blumlein modules, and phasing is controlled by adjusting the length of fiber optic cables that carry the laser light to the insulator surface.
Inpainting with sparse linear combinations of exemplars
Wohlberg, Brendt
2008-01-01
We introduce a new exemplar-based inpainting algorithm based on representing the region to be inpainted as a sparse linear combination of blocks extracted from similar parts of the image being inpainted. This method is conceptually simple, being computed by functional minimization, and avoids the complexity of correctly ordering the filling in of missing regions of other exemplar-based methods. Initial performance comparisons on small inpainting regions indicate that this method provides similar or better performance than other recent methods.
Radio frequency quadrupole resonator for linear accelerator
Moretti, Alfred
1985-01-01
An RFQ resonator for a linear accelerator having a reduced level of interfering modes and producing a quadrupole mode for focusing, bunching and accelerating beams of heavy charged particles, with the construction being characterized by four elongated resonating rods within a cylinder with the rods being alternately shorted and open electrically to the shell at common ends of the rods to provide an LC parallel resonant circuit when activated by a magnetic field transverse to the longitudinal axis.
Communications circuit including a linear quadratic estimator
Ferguson, Dennis D.
2015-07-07
A circuit includes a linear quadratic estimator (LQE) configured to receive a plurality of measurements a signal. The LQE is configured to weight the measurements based on their respective uncertainties to produce weighted averages. The circuit further includes a controller coupled to the LQE and configured to selectively adjust at least one data link parameter associated with a communication channel in response to receiving the weighted averages.
High gradient accelerators for linear light sources
Barletta, W.A.
1988-09-26
Ultra-high gradient radio frequency linacs powered by relativistic klystrons appear to be able to provide compact sources of radiation at XUV and soft x-ray wavelengths with a duration of 1 picosecond or less. This paper provides a tutorial review of the physics applicable to scaling the present experience of the accelerator community to the regime applicable to compact linear light sources. 22 refs., 11 figs., 21 tabs.
The Next Linear Collider: NLC2001
D. Burke et al.
2002-01-14
Recent studies in elementary particle physics have made the need for an e{sup +}e{sup -} linear collider able to reach energies of 500 GeV and above with high luminosity more compelling than ever [1]. Observations and measurements completed in the last five years at the SLC (SLAC), LEP (CERN), and the Tevatron (FNAL) can be explained only by the existence of at least one particle or interaction that has not yet been directly observed in experiment. The Higgs boson of the Standard Model could be that particle. The data point strongly to a mass for the Higgs boson that is just beyond the reach of existing colliders. This brings great urgency and excitement to the potential for discovery at the upgraded Tevatron early in this decade, and almost assures that later experiments at the LHC will find new physics. But the next generation of experiments to be mounted by the world-wide particle physics community must not only find this new physics, they must find out what it is. These experiments must also define the next important threshold in energy. The need is to understand physics at the TeV energy scale as well as the physics at the 100-GeV energy scale is now understood. This will require both the LHC and a companion linear electron-positron collider. A first Zeroth-Order Design Report (ZDR) [2] for a second-generation electron-positron linear collider, the Next Linear Collider (NLC), was published five years ago. The NLC design is based on a high-frequency room-temperature rf accelerator. Its goal is exploration of elementary particle physics at the TeV center-of-mass energy, while learning how to design and build colliders at still higher energies. Many advances in accelerator technologies and improvements in the design of the NLC have been made since 1996. This Report is a brief update of the ZDR.
Towards a Future Linear Collider and The Linear Collider Studies at CERN
None
2011-10-06
During the week 18-22 October, more than 400 physicists will meet at CERN and in the CICG (International Conference Centre Geneva) to review the global progress towards a future linear collider. The 2010 International Workshop on Linear Colliders will study the physics, detectors and accelerator complex of a linear collider covering both the CLIC and ILC options. Among the topics presented and discussed will be the progress towards the CLIC Conceptual Design Report in 2011, the ILC Technical Design Report in 2012, physics and detector studies linked to these reports, and an increasing numbers of common working group activities. The seminar will give an overview of these topics and also CERN?s linear collider studies, focusing on current activities and initial plans for the period 2011-16. n.b: The Council Chamber is also reserved for this colloquium with a live transmission from the Main Auditorium.
Linear Collider Physics Resource Book Snowmass 2001
Ronan , M.T.
2001-06-01
The American particle physics community can look forward to a well-conceived and vital program of experimentation for the next ten years, using both colliders and fixed target beams to study a wide variety of pressing questions. Beyond 2010, these programs will be reaching the end of their expected lives. The CERN LHC will provide an experimental program of the first importance. But beyond the LHC, the American community needs a coherent plan. The Snowmass 2001 Workshop and the deliberations of the HEPAP subpanel offer a rare opportunity to engage the full community in planning our future for the next decade or more. A major accelerator project requires a decade from the beginning of an engineering design to the receipt of the first data. So it is now time to decide whether to begin a new accelerator project that will operate in the years soon after 2010. We believe that the world high-energy physics community needs such a project. With the great promise of discovery in physics at the next energy scale, and with the opportunity for the uncovering of profound insights, we cannot allow our field to contract to a single experimental program at a single laboratory in the world. We believe that an e{sup +}e{sup -} linear collider is an excellent choice for the next major project in high-energy physics. Applying experimental techniques very different from those used at hadron colliders, an e{sup +}e{sup -} linear collider will allow us to build on the discoveries made at the Tevatron and the LHC, and to add a level of precision and clarity that will be necessary to understand the physics of the next energy scale. It is not necessary to anticipate specific results from the hadron collider programs to argue for constructing an e{sup +}e{sup -} linear collider; in any scenario that is now discussed, physics will benefit from the new information that e{sup +}e{sup -} experiments can provide. This last point merits further emphasis. If a new accelerator could be designed and
Microfabricated linear Paul-Straubel ion trap
Mangan, Michael A.; Blain, Matthew G.; Tigges, Chris P.; Linker, Kevin L.
2011-04-19
An array of microfabricated linear Paul-Straubel ion traps can be used for mass spectrometric applications. Each ion trap comprises two parallel inner RF electrodes and two parallel outer DC control electrodes symmetric about a central trap axis and suspended over an opening in a substrate. Neighboring ion traps in the array can share a common outer DC control electrode. The ions confined transversely by an RF quadrupole electric field potential well on the ion trap axis. The array can trap a wide array of ions.
Micromechanism linear actuator with capillary force sealing
Sniegowski, Jeffry J.
1997-01-01
A class of micromachine linear actuators whose function is based on gas driven pistons in which capillary forces are used to seal the gas behind the piston. The capillary forces also increase the amount of force transmitted from the gas pressure to the piston. In a major subclass of such devices, the gas bubble is produced by thermal vaporization of a working fluid. Because of their dependence on capillary forces for sealing, such devices are only practical on the sub-mm size scale, but in that regime they produce very large force times distance (total work) values.
Rf power sources for linear colliders
Allen, M.A.; Callin, R.S.; Caryotakis, G.; Deruyter, H.; Eppley, K.R.; Fant, K.S.; Farkas, Z.D.; Fowkes, W.R.; Hoag, H.A.; Feinstein, J.; Ko, K.; Koontz, R.F.; Kroll, N.M.; Lavine, T.L.; Lee, T.G.; Loew, G.A.; Miller, R.H.; Nelson, E.M.; Ruth, R.D.; Vlieks, A.E.; Wang, J.W.; Wilson, P.B. ); Boyd, J.K.; Houk, T.; Ryne, R.D.; Westenskow, G.A.; Yu, S.S. (Lawrence Live
1990-06-01
The next generation of linear colliders requires peak power sources of over 200 MW per meter at frequencies above 10 GHz at pulse widths of less than 100 nsec. Several power sources are under active development, including a conventional klystron with rf pulse compression, a relativistic klystron (RK) and a crossed-field amplifier. Power from one of these has energized a 0.5 meter two- section High Gradient Accelerator (HGA) and accelerated a beam at over 80 MeV meter. Results of tests with these experimental devices are presented here.
Limits on linearity of missile allocation optimization
Canavan, G.H.
1997-12-01
Optimizations of missile allocation based on linearized exchange equations produce accurate allocations, but the limits of validity of the linearization are not known. These limits are explored in the context of the upload of weapons by one side to initially small, equal forces of vulnerable and survivable weapons. The analysis compares analytic and numerical optimizations and stability induces based on aggregated interactions of the two missile forces, the first and second strikes they could deliver, and they resulting costs. This note discusses the costs and stability indices induced by unilateral uploading of weapons to an initially symmetrical low force configuration. These limits are quantified for forces with a few hundred missiles by comparing analytic and numerical optimizations of first strike costs. For forces of 100 vulnerable and 100 survivable missiles on each side, the analytic optimization agrees closely with the numerical solution. For 200 vulnerable and 200 survivable missiles on each side, the analytic optimization agrees with the induces to within about 10%, but disagrees with the allocation of the side with more weapons by about 50%. The disagreement comes from the interaction of the possession of more weapons with the shift of allocation from missiles to value that they induce.
Terahertz-driven linear electron acceleration
Nanni, Emilio A.; Huang, Wenqian R.; Hong, Kyung-Han; Ravi, Koustuban; Fallahi, Arya; Moriena, Gustavo; Dwayne Miller, R. J.; Kärtner, Franz X.
2015-10-06
The cost, size and availability of electron accelerators are dominated by the achievable accelerating gradient. Conventional high-brightness radio-frequency accelerating structures operate with 30–50 MeVm^{-1 }gradients. Electron accelerators driven with optical or infrared sources have demonstrated accelerating gradients orders of magnitude above that achievable with conventional radio-frequency structures. However, laser-driven wakefield accelerators require intense femtosecond sources and direct laser-driven accelerators suffer from low bunch charge, sub-micron tolerances and sub-femtosecond timing requirements due to the short wavelength of operation. Here we demonstrate linear acceleration of electrons with keV energy gain using optically generated terahertz pulses. Terahertz-driven accelerating structures enable high-gradient electron/proton accelerators with simple accelerating structures, high repetition rates and significant charge per bunch. As a result, these ultra-compact terahertz accelerators with extremely short electron bunches hold great potential to have a transformative impact for free electron lasers, linear colliders, ultrafast electron diffraction, X-ray science and medical therapy with X-rays and electron beams.
Terahertz-driven linear electron acceleration
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Nanni, Emilio A.; Huang, Wenqian R.; Hong, Kyung-Han; Ravi, Koustuban; Fallahi, Arya; Moriena, Gustavo; Dwayne Miller, R. J.; Kärtner, Franz X.
2015-10-06
The cost, size and availability of electron accelerators are dominated by the achievable accelerating gradient. Conventional high-brightness radio-frequency accelerating structures operate with 30–50 MeVm-1 gradients. Electron accelerators driven with optical or infrared sources have demonstrated accelerating gradients orders of magnitude above that achievable with conventional radio-frequency structures. However, laser-driven wakefield accelerators require intense femtosecond sources and direct laser-driven accelerators suffer from low bunch charge, sub-micron tolerances and sub-femtosecond timing requirements due to the short wavelength of operation. Here we demonstrate linear acceleration of electrons with keV energy gain using optically generated terahertz pulses. Terahertz-driven accelerating structures enable high-gradient electron/proton acceleratorsmore » with simple accelerating structures, high repetition rates and significant charge per bunch. As a result, these ultra-compact terahertz accelerators with extremely short electron bunches hold great potential to have a transformative impact for free electron lasers, linear colliders, ultrafast electron diffraction, X-ray science and medical therapy with X-rays and electron beams.« less
Linear dimensions and volumes of human lungs
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Hickman, David P.
2012-03-30
TOTAL LUNG Capacity is defined as “the inspiratory capacity plus the functional residual capacity; the volume of air contained in the lungs at the end of a maximal inspiration; also equals vital capacity plus residual volume” (from MediLexicon.com). Within the Results and Discussion section of their April 2012 Health Physics paper, Kramer et al. briefly noted that the lungs of their experimental subjects were “not fully inflated.” By definition and failure to obtain maximal inspiration, Kramer et. al. did not measure Total Lung Capacity (TLC). The TLC equation generated from this work will tend to underestimate TLC and does notmore » improve or update total lung capacity data provided by ICRP and others. Likewise, the five linear measurements performed by Kramer et. al. are only representative of the conditions of the measurement (i.e., not at-rest volume, but not fully inflated either). While there was significant work performed and the data are interesting, the data does not represent a maximal situation, a minimal situation, or an at-rest situation. Moreover, while interesting, the linear data generated by this study is limited by the conditions of the experiment and may not be fully comparative with other lung or inspiratory parameters, measures, or physical dimensions.« less
TLD linearity vs. beam energy and modality
Troncalli, Andrew J.; Chapman, Jane
2002-12-31
Thermoluminescent dosimetry (TLD) is considered to be a valuable dosimetric tool in determining patient dose. Lithium fluoride doped with magnesium and titanium (TLD-100) is widely used, as it does not display widely divergent energy dependence. For many years, we have known that TLD-100 shows supralinearity to dose. In a radiotherapy clinic, there are multiple energies and modality beams. This work investigates whether individual linearity corrections must be used for each beam or whether a single correction can be applied to all beams. The response of TLD as a function of dose was measured from 25 cGy to 1000 cGy on both electrons and photons from 6 to 18 MeV. This work shows that, within our measurement uncertainty, TLD-100 exhibits supralinearity at all megavoltage energies and modalities.
Shortcuts to adiabaticity from linear response theory
Acconcia, Thiago V.; Bonança, Marcus V. S.; Deffner, Sebastian
2015-10-23
A shortcut to adiabaticity is a finite-time process that produces the same final state as would result from infinitely slow driving. We show that such shortcuts can be found for weak perturbations from linear response theory. Moreover, with the help of phenomenological response functions, a simple expression for the excess work is found—quantifying the nonequilibrium excitations. For two specific examples, i.e., the quantum parametric oscillator and the spin 1/2 in a time-dependent magnetic field, we show that finite-time zeros of the excess work indicate the existence of shortcuts. We finally propose a degenerate family of protocols, which facilitates shortcuts to adiabaticity for specific and very short driving times.
Shortcuts to adiabaticity from linear response theory
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Acconcia, Thiago V.; Bonança, Marcus V. S.; Deffner, Sebastian
2015-10-23
A shortcut to adiabaticity is a finite-time process that produces the same final state as would result from infinitely slow driving. We show that such shortcuts can be found for weak perturbations from linear response theory. Moreover, with the help of phenomenological response functions, a simple expression for the excess work is found—quantifying the nonequilibrium excitations. For two specific examples, i.e., the quantum parametric oscillator and the spin 1/2 in a time-dependent magnetic field, we show that finite-time zeros of the excess work indicate the existence of shortcuts. We finally propose a degenerate family of protocols, which facilitates shortcuts tomore » adiabaticity for specific and very short driving times.« less
Linear nozzle with tailored gas plumes
Leon, David D.; Kozarek, Robert L.; Mansour, Adel; Chigier, Norman
2001-01-01
There is claimed a method for depositing fluid material from a linear nozzle in a substantially uniform manner across and along a surface. The method includes directing gaseous medium through said nozzle to provide a gaseous stream at the nozzle exit that entrains fluid material supplied to the nozzle, said gaseous stream being provided with a velocity profile across the nozzle width that compensates for the gaseous medium's tendency to assume an axisymmetric configuration after leaving the nozzle and before reaching the surface. There is also claimed a nozzle divided into respective side-by-side zones, or preferably chambers, through which a gaseous stream can be delivered in various velocity profiles across the width of said nozzle to compensate for the tendency of this gaseous medium to assume an axisymmetric configuration.
Linear nozzle with tailored gas plumes
Kozarek, Robert L.; Straub, William D.; Fischer, Joern E.; Leon, David D.
2003-01-01
There is claimed a method for depositing fluid material from a linear nozzle in a substantially uniform manner across and along a surface. The method includes directing gaseous medium through said nozzle to provide a gaseous stream at the nozzle exit that entrains fluid material supplied to the nozzle, said gaseous stream being provided with a velocity profile across the nozzle width that compensates for the gaseous medium's tendency to assume an axisymmetric configuration after leaving the nozzle and before reaching the surface. There is also claimed a nozzle divided into respective side-by-side zones, or preferably chambers, through which a gaseous stream can be delivered in various velocity profiles across the width of said nozzle to compensate for the tendency of this gaseous medium to assume an axisymmetric configuration.
Radio frequency focused interdigital linear accelerator
Swenson, Donald A.; Starling, W. Joel
2006-08-29
An interdigital (Wideroe) linear accelerator employing drift tubes, and associated support stems that couple to both the longitudinal and support stem electromagnetic fields of the linac, creating rf quadrupole fields along the axis of the linac to provide transverse focusing for the particle beam. Each drift tube comprises two separate electrodes operating at different electrical potentials as determined by cavity rf fields. Each electrode supports two fingers, pointing towards the opposite end of the drift tube, forming a four-finger geometry that produces an rf quadrupole field distribution along its axis. The fundamental periodicity of the structure is equal to one half of the particle wavelength .beta..lamda., where .beta. is the particle velocity in units of the velocity of light and .lamda. is the free space wavelength of the rf. Particles are accelerated in the gaps between drift tubes. The particle beam is focused in regions inside the drift tubes.
Faraday rotation assisted by linearly polarized light
Choi, Jai Min; Kim, Jang Myun; Cho, D.
2007-11-15
We demonstrate a type of chiral effect of an atomic medium. Polarization rotation of a probe beam is observed only when both a magnetic field and a linearly polarized coupling beam are present. We compare it with other chiral effects like optical activity, the Faraday effect, and the optically induced Faraday effect from the viewpoint of spatial inversion and time reversal transformations. As a theoretical model we consider a five-level configuration involving the cesium D2 transition. We use spin-polarized cold cesium atoms trapped in a magneto-optical trap to measure the polarization rotation versus probe detuning. The result shows reasonable agreement with a calculation from the master equation of the five-level configuration.
2d PDE Linear Symmetric Matrix Solver
Energy Science and Technology Software Center (OSTI)
1983-10-01
ICCG2 (Incomplete Cholesky factorized Conjugate Gradient algorithm for 2d symmetric problems) was developed to solve a linear symmetric matrix system arising from a 9-point discretization of two-dimensional elliptic and parabolic partial differential equations found in plasma physics applications, such as resistive MHD, spatial diffusive transport, and phase space transport (Fokker-Planck equation) problems. These problems share the common feature of being stiff and requiring implicit solution techniques. When these parabolic or elliptic PDE''s are discretized withmore » finite-difference or finite-element methods,the resulting matrix system is frequently of block-tridiagonal form. To use ICCG2, the discretization of the two-dimensional partial differential equation and its boundary conditions must result in a block-tridiagonal supermatrix composed of elementary tridiagonal matrices. The incomplete Cholesky conjugate gradient algorithm is used to solve the linear symmetric matrix equation. Loops are arranged to vectorize on the Cray1 with the CFT compiler, wherever possible. Recursive loops, which cannot be vectorized, are written for optimum scalar speed. For matrices lacking symmetry, ILUCG2 should be used. Similar methods in three dimensions are available in ICCG3 and ILUCG3. A general source containing extensions and macros, which must be processed by a pre-compiler to obtain the standard FORTRAN source, is provided along with the standard FORTRAN source because it is believed to be more readable. The pre-compiler is not included, but pre-compilation may be performed by a text editor as described in the UCRL-88746 Preprint.« less
International linear collider reference design report
Aarons, G.
2007-06-22
The International Linear Collider will give physicists a new cosmic doorway to explore energy regimes beyond the reach of today's accelerators. A proposed electron-positron collider, the ILC will complement the Large Hadron Collider, a proton-proton collider at the European Center for Nuclear Research (CERN) in Geneva, Switzerland, together unlocking some of the deepest mysteries in the universe. With LHC discoveries pointing the way, the ILC -- a true precision machine -- will provide the missing pieces of the puzzle. Consisting of two linear accelerators that face each other, the ILC will hurl some 10 billion electrons and their anti-particles, positrons, toward each other at nearly the speed of light. Superconducting accelerator cavities operating at temperatures near absolute zero give the particles more and more energy until they smash in a blazing crossfire at the centre of the machine. Stretching approximately 35 kilometres in length, the beams collide 14,000 times every second at extremely high energies -- 500 billion-electron-volts (GeV). Each spectacular collision creates an array of new particles that could answer some of the most fundamental questions of all time. The current baseline design allows for an upgrade to a 50-kilometre, 1 trillion-electron-volt (TeV) machine during the second stage of the project. This reference design provides the first detailed technical snapshot of the proposed future electron-positron collider, defining in detail the technical parameters and components that make up each section of the 31-kilometer long accelerator. The report will guide the development of the worldwide R&D program, motivate international industrial studies and serve as the basis for the final engineering design needed to make an official project proposal later this decade.
Linear-array systems for aerospace NDE
Smith, Robert A.; Willsher, Stephen J.; Bending, Jamie M.
1999-12-02
Rapid large-area inspection of composite structures for impact damage and multi-layered aluminum skins for corrosion has been a recognized priority for several years in both military and civil aerospace applications. Approaches to this requirement have followed two clearly different routes: the development of novel large-area inspection systems, and the enhancement of current ultrasonic or eddy-current methods to reduce inspection times. Ultrasonic inspection is possible with standard flaw detection equipment but the addition of a linear ultrasonic array could reduce inspection times considerably. In order to investigate their potential, 9-element and 17-element linear ultrasonic arrays for composites, and 64-element arrays for aluminum skins, have been developed to DERA specifications for use with the ANDSCAN area scanning system. A 5 m{sup 2} composite wing surface has been scanned with a scan resolution of approximately 3 mm in 6 hours. With subsequent software and hardware improvements all four composite wing surfaces (top/bottom, left/right) of a military fighter aircraft can potentially be inspected in less than a day. Array technology has been very widely used in the medical ultrasound field although rarely above 10 MHz, whereas lap-joint inspection requires a pulse center-frequency of 12 to 20 MHz in order to resolve the separate interfaces in the lap joint. A 128 mm-long multi-element array of 5 mmx2 mm ultrasonic elements for use with the ANDSCAN scanning software was produced to a DERA specification by an NDT manufacturer with experience in the medical imaging field. This paper analyses the performance of the transducers that have been produced and evaluates their use in scanning systems of different configurations.
Project Profile: Commercial Development of an Advanced Linear...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Project Profile: Commercial Development of an Advanced Linear-Fresnel-Based CSP Concept SkyFuel logo SkyFuel, under the CSP R&D FOA, is developing a commercial linear-Fresnel-based ...
CALiPER Application Summary Report 19. LED Linear Pendants
none,
2012-10-01
Report 19 reviews the independently tested performance of nine LED linear pendants and also evaluates a collection of 11 linear pendant products available in both an LED and fluorescent version.
Governance of the International Linear Collider Project
Foster, B.; Barish, B.; Delahaye, J.P.; Dosselli, U.; Elsen, E.; Harrison, M.; Mnich, J.; Paterson, J.M.; Richard, F.; Stapnes, S.; Suzuki, A.; Wormser, G.; Yamada, S.; /KEK, Tsukuba
2012-05-31
Governance models for the International Linear Collider Project are examined in the light of experience from similar international projects around the world. Recommendations for one path which could be followed to realize the ILC successfully are outlined. The International Linear Collider (ILC) is a unique endeavour in particle physics; fully international from the outset, it has no 'host laboratory' to provide infrastructure and support. The realization of this project therefore presents unique challenges, in scientific, technical and political arenas. This document outlines the main questions that need to be answered if the ILC is to become a reality. It describes the methodology used to harness the wisdom displayed and lessons learned from current and previous large international projects. From this basis, it suggests both general principles and outlines a specific model to realize the ILC. It recognizes that there is no unique model for such a laboratory and that there are often several solutions to a particular problem. Nevertheless it proposes concrete solutions that the authors believe are currently the best choices in order to stimulate discussion and catalyze proposals as to how to bring the ILC project to fruition. The ILC Laboratory would be set up by international treaty and be governed by a strong Council to whom a Director General and an associated Directorate would report. Council would empower the Director General to give strong management to the project. It would take its decisions in a timely manner, giving appropriate weight to the financial contributions of the member states. The ILC Laboratory would be set up for a fixed term, capable of extension by agreement of all the partners. The construction of the machine would be based on a Work Breakdown Structure and value engineering and would have a common cash fund sufficiently large to allow the management flexibility to optimize the project's construction. Appropriate contingency, clearly
Linear air-fuel sensor development
Garzon, F.; Miller, C.
1996-12-14
The electrochemical zirconia solid electrolyte oxygen sensor, is extensively used for monitoring oxygen concentrations in various fields. They are currently utilized in automobiles to monitor the exhaust gas composition and control the air-to-fuel ratio, thus reducing harmful emission components and improving fuel economy. Zirconia oxygen sensors, are divided into two classes of devices: (1) potentiometric or logarithmic air/fuel sensors; and (2) amperometric or linear air/fuel sensors. The potentiometric sensors are ideally suited to monitor the air-to-fuel ratio close to the complete combustion stoichiometry; a value of about 14.8 to 1 parts by volume. This occurs because the oxygen concentration changes by many orders of magnitude as the air/fuel ratio is varied through the stoichiometric value. However, the potentiometric sensor is not very sensitive to changes in oxygen partial pressure away from the stoichiometric point due to the logarithmic dependence of the output voltage signal on the oxygen partial pressure. It is often advantageous to operate gasoline power piston engines with excess combustion air; this improves fuel economy and reduces hydrocarbon emissions. To maintain stable combustion away from stoichiometry, and enable engines to operate in the excess oxygen (lean burn) region several limiting-current amperometric sensors have been reported. These sensors are based on the electrochemical oxygen ion pumping of a zirconia electrolyte. They typically show reproducible limiting current plateaus with an applied voltage caused by the gas diffusion overpotential at the cathode.
VINETA II: A linear magnetic reconnection experiment
Bohlin, H. Von Stechow, A.; Rahbarnia, K.; Grulke, O.; Klinger, T.; Ernst-Moritz-Arndt University, Domstr. 11, 17489 Greifswald
2014-02-15
A linear experiment dedicated to the study of driven magnetic reconnection is presented. The new device (VINETA II) is suitable for investigating both collisional and near collisionless reconnection. Reconnection is achieved by externally driving magnetic field lines towards an X-point, inducing a current in the background plasma which consequently modifies the magnetic field topology. Owing to the open field line configuration of the experiment, the current is limited by the axial sheath boundary conditions. A plasma gun is used as an additional electron source in order to counterbalance the charge separation effects and supply the required current. Two drive methods are used in the device. First, an oscillating current through two parallel conductors drive the reconnection. Second, a stationary X-point topology is formed by the parallel conductors, and the drive is achieved by an oscillating current through a third conductor. In the first setup, the magnetic field of the axial plasma current dominates the field topology near the X-point throughout most of the drive. The second setup allows for the amplitude of the plasma current as well as the motion of the flux to be set independently of the X-point topology of the parallel conductors.
Precision envelope detector and linear rectifier circuitry
Davis, Thomas J.
1980-01-01
Disclosed is a method and apparatus for the precise linear rectification and envelope detection of oscillatory signals. The signal is applied to a voltage-to-current converter which supplies current to a constant current sink. The connection between the converter and the sink is also applied through a diode and an output load resistor to a ground connection. The connection is also connected to ground through a second diode of opposite polarity from the diode in series with the load resistor. Very small amplitude voltage signals applied to the converter will cause a small change in the output current of the converter, and the difference between the output current and the constant current sink will be applied either directly to ground through the single diode, or across the output load resistor, dependent upon the polarity. Disclosed also is a full-wave rectifier utilizing constant current sinks and voltage-to-current converters. Additionally, disclosed is a combination of the voltage-to-current converters with differential integrated circuit preamplifiers to boost the initial signal amplitude, and with low pass filtering applied so as to obtain a video or signal envelope output.
Liquid cooled, linear focus solar cell receiver
Kirpich, A.S.
1983-12-08
Separate structures for electrical insulation and thermal conduction are established within a liquid cooled, linear focus solar cell receiver for use with parabolic or Fresnel optical concentrators. The receiver includes a V-shaped aluminum extrusion having a pair of outer faces each formed with a channel receiving a string of solar cells in thermal contact with the extrusion. Each cell string is attached to a continuous glass cover secured within the channel with spring clips to isolate the string from the external environment. Repair or replacement of solar cells is effected simply by detaching the spring clips to remove the cover/cell assembly without interrupting circulation of coolant fluid through the receiver. The lower surface of the channel in thermal contact with the cells of the string is anodized to establish a suitable standoff voltage capability between the cells and the extrusion. Primary electrical insulation is provided by a dielectric tape disposed between the coolant tube and extrusion. Adjacent solar cells are soldered to interconnect members designed to accommodate thermal expansion and mismatches. The coolant tube is clamped into the extrusion channel with a releasably attachable clamping strip to facilitate easy removal of the receiver from the coolant circuit.
Liquid cooled, linear focus solar cell receiver
Kirpich, Aaron S.
1985-01-01
Separate structures for electrical insulation and thermal conduction are established within a liquid cooled, linear focus solar cell receiver for use with parabolic or Fresnel optical concentrators. The receiver includes a V-shaped aluminum extrusion having a pair of outer faces each formed with a channel receiving a string of solar cells in thermal contact with the extrusion. Each cell string is attached to a continuous glass cover secured within the channel with spring clips to isolate the string from the external environment. Repair or replacement of solar cells is effected simply by detaching the spring clips to remove the cover/cell assembly without interrupting circulation of coolant fluid through the receiver. The lower surface of the channel in thermal contact with the cells of the string is anodized to establish a suitable standoff voltage capability between the cells and the extrusion. Primary electrical insulation is provided by a dielectric tape disposed between the coolant tube and extrusion. Adjacent solar cells are soldered to interconnect members designed to accommodate thermal expansion and mismatches. The coolant tube is clamped into the extrusion channel with a releasably attachable clamping strip to facilitate easy removal of the receiver from the coolant circuit.
Linear Fixed-Field Multi-Pass Arcs for Recirculating Linear Accelerators
V.S. Morozov, S.A. Bogacz, Y.R. Roblin, K.B. Beard
2012-06-01
Recirculating Linear Accelerators (RLA's) provide a compact and efficient way of accelerating particle beams to medium and high energies by reusing the same linac for multiple passes. In the conventional scheme, after each pass, the different energy beams coming out of the linac are separated and directed into appropriate arcs for recirculation, with each pass requiring a separate fixed-energy arc. In this paper we present a concept of an RLA return arc based on linear combined-function magnets, in which two and potentially more consecutive passes with very different energies are transported through the same string of magnets. By adjusting the dipole and quadrupole components of the constituting linear combined-function magnets, the arc is designed to be achromatic and to have zero initial and final reference orbit offsets for all transported beam energies. We demonstrate the concept by developing a design for a droplet-shaped return arc for a dog-bone RLA capable of transporting two beam passes with momenta different by a factor of two. We present the results of tracking simulations of the two passes and lay out the path to end-to-end design and simulation of a complete dog-bone RLA.
High-gradient compact linear accelerator
Carder, B.M.
1998-05-26
A high-gradient linear accelerator comprises a solid-state stack in a vacuum of five sets of disc-shaped Blumlein modules each having a center hole through which particles are sequentially accelerated. Each Blumlein module is a sandwich of two outer conductive plates that bracket an inner conductive plate positioned between two dielectric plates with different thicknesses and dielectric constants. A third dielectric core in the shape of a hollow cylinder forms a casing down the series of center holes, and it has a dielectric constant different that the two dielectric plates that sandwich the inner conductive plate. In operation, all the inner conductive plates are charged to the same DC potential relative to the outer conductive plates. Next, all the inner conductive plates are simultaneously shorted to the outer conductive plates at the outer diameters. The signal short will propagate to the inner diameters at two different rates in each Blumlein module. A faster wave propagates quicker to the third dielectric core across the dielectric plates with the closer spacing and lower dielectric constant. When the faster wave reaches the inner extents of the outer and inner conductive plates, it reflects back outward and reverses the field in that segment of the dielectric core. All the field segments in the dielectric core are then in unipolar agreement until the slower wave finally propagates to the third dielectric core across the dielectric plates with the wider spacing and higher dielectric constant. During such unipolar agreement, particles in the core are accelerated with gradients that exceed twenty megavolts per meter. 10 figs.
High-gradient compact linear accelerator
Carder, Bruce M.
1998-01-01
A high-gradient linear accelerator comprises a solid-state stack in a vacuum of five sets of disc-shaped Blumlein modules each having a center hole through which particles are sequentially accelerated. Each Blumlein module is a sandwich of two outer conductive plates that bracket an inner conductive plate positioned between two dielectric plates with different thicknesses and dielectric constants. A third dielectric core in the shape of a hollow cylinder forms a casing down the series of center holes, and it has a dielectric constant different that the two dielectric plates that sandwich the inner conductive plate. In operation, all the inner conductive plates are charged to the same DC potential relative to the outer conductive plates. Next, all the inner conductive plates are simultaneously shorted to the outer conductive plates at the outer diameters. The signal short will propagate to the inner diameters at two different rates in each Blumlein module. A faster wave propagates quicker to the third dielectric core across the dielectric plates with the closer spacing and lower dielectric constant. When the faster wave reaches the inner extents of the outer and inner conductive plates, it reflects back outward and reverses the field in that segment of the dielectric core. All the field segments in the dielectric core are then in unipolar agreement until the slower wave finally propagates to the third dielectric core across the dielectric plates with the wider spacing and higher dielectric constant. During such unipolar agreement, particles in the core are accelerated with gradients that exceed twenty megavolts per meter.
2d PDE Linear Asymmetric Matrix Solver
Energy Science and Technology Software Center (OSTI)
1983-10-01
ILUCG2 (Incomplete LU factorized Conjugate Gradient algorithm for 2d problems) was developed to solve a linear asymmetric matrix system arising from a 9-point discretization of two-dimensional elliptic and parabolic partial differential equations found in plasma physics applications, such as plasma diffusion, equilibria, and phase space transport (Fokker-Planck equation) problems. These equations share the common feature of being stiff and requiring implicit solution techniques. When these parabolic or elliptic PDE''s are discretized with finite-difference or finite-elementmore » methods, the resulting matrix system is frequently of block-tridiagonal form. To use ILUCG2, the discretization of the two-dimensional partial differential equation and its boundary conditions must result in a block-tridiagonal supermatrix composed of elementary tridiagonal matrices. A generalization of the incomplete Cholesky conjugate gradient algorithm is used to solve the matrix equation. Loops are arranged to vectorize on the Cray1 with the CFT compiler, wherever possible. Recursive loops, which cannot be vectorized, are written for optimum scalar speed. For problems having a symmetric matrix ICCG2 should be used since it runs up to four times faster and uses approximately 30% less storage. Similar methods in three dimensions are available in ICCG3 and ILUCG3. A general source, containing extensions and macros, which must be processed by a pre-compiler to obtain the standard FORTRAN source, is provided along with the standard FORTRAN source because it is believed to be more readable. The pre-compiler is not included, but pre-compilation may be performed by a text editor as described in the UCRL-88746 Preprint.« less
Electronic Non-Contacting Linear Position Measuring System
Post, Richard F.
2005-06-14
A non-contacting linear position location system employs a special transmission line to encode and transmit magnetic signals to a receiver on the object whose position is to be measured. The invention is useful as a non-contact linear locator of moving objects, e.g., to determine the location of a magnetic-levitation train for the operation of the linear-synchronous motor drive system.
The Linear Engine Pathway of Transformation | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
The Linear Engine Pathway of Transformation The Linear Engine Pathway of Transformation This poster highlights the major milestones in the history of the linear engine in terms of technological advances, novel designs, and economic/social impact. p-06_covington.pdf (214.04 KB) More Documents & Publications Difficulty of Measuring Emissions from Heavy-Duty Engines Equipped with SCR and DPF Development of a Stand-Alone Urea-SCR System for NOx Reduction in Marine Diesel Engines Modeling the
Knot Undulator to Generate Linearly Polarized Photons with Low...
Office of Scientific and Technical Information (OSTI)
Heat load on beamline optics is a serious problem to generate pure linearly polarized ... Language: English Subject: 43 PARTICLE ACCELERATORS; OPTICS; PERMANENT MAGNETS; PHOTONS; ...
Vibronic coupling simulations for linear and nonlinear optical...
Office of Scientific and Technical Information (OSTI)
optical processes: Theory Citation Details In-Document Search Title: Vibronic coupling simulations for linear and nonlinear optical processes: Theory A comprehensive vibronic ...
DOE - Office of Legacy Management -- Stanford Linear Accelerator...
Office of Legacy Management (LM)
The Stanford Linear Accelerator Center was established in 1962 as a research facility for high energy particle physics. The Environmental Management mission at this site is to ...
Optimizing minimum free-energy crossing points in solution: Linear...
Office of Scientific and Technical Information (OSTI)
Optimizing minimum free-energy crossing points in solution: Linear-response free energyspin-flip density functional theory approach Citation Details In-Document Search Title:...
Linear electric field time-of-flight ion mass spectrometer
Funsten, Herbert O.; Feldman, William C.
2008-06-10
A linear electric field ion mass spectrometer having an evacuated enclosure with means for generating a linear electric field located in the evacuated enclosure and means for injecting a sample material into the linear electric field. A source of pulsed ionizing radiation injects ionizing radiation into the linear electric field to ionize atoms or molecules of the sample material, and timing means determine the time elapsed between ionization of atoms or molecules and arrival of an ion out of the ionized atoms or molecules at a predetermined position.
Top Quark Anomalous Couplings at the International Linear Collider...
Office of Scientific and Technical Information (OSTI)
to a precision of approximately 1% for each of two choices of beam polarization. ... INTERMEDIATE BOSONS; LINEAR COLLIDERS; POLARIZATION; PROBES; QUARKS; SILICON; SIMULATION; ...
The Klynac: An Integrated Klystron and Linear Accelerator
Potter, J. M., Schwellenbach, D., Meidinger, A.
2012-08-07
The Klynac concept integrates an electron gun, a radio frequency (RF) power source, and a coupled-cavity linear accelerator into a single resonant system
Knot Undulator to Generate Linearly Polarized Photons with Low...
Office of Scientific and Technical Information (OSTI)
pure linearly polarized photons in the third generation synchrotron radiation facilities. ... Sponsoring Org: USDOE Country of Publication: United States Language: English Subject: 43 ...
A posteriori error analysis of parameterized linear systems using...
Office of Scientific and Technical Information (OSTI)
Journal Article: A posteriori error analysis of parameterized linear systems using spectral methods. Citation Details In-Document Search Title: A posteriori error analysis of ...
Self-Sustained Micromechanical Oscillator with Linear Feedback...
Office of Scientific and Technical Information (OSTI)
Publisher's Accepted Manuscript: Self-Sustained Micromechanical Oscillator with Linear Feedback This content will become publicly available on July 1, 2017 Prev Next Title: ...
Entropy-based separation of linear chain molecules by exploiting...
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Entropy-based separation of linear chain molecules by exploiting differences in the saturation capacities in cage-type zeolites Previous Next List Rajamani Krishna, Jasper M. van...
Simultaneous linear optics and coupling correction for storage...
Office of Scientific and Technical Information (OSTI)
Journal Article: Simultaneous linear optics and coupling correction for storage rings with turn-by-turn beam position monitor data Citation Details In-Document Search Title:...
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism
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Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism Print Using spectroscopic ... The effect is unique in that it allows us to distinguish which atomic species magnetism ...
A Linear Theory of Microwave Instability in Electron Storage...
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Title: A Linear Theory of Microwave Instability in Electron Storage Rings The well-known Haissinski distribution provides a stable equilibrium of longitudinal beam distribution in ...
Linearly Polarized Thermal Emitter for More Efficient Thermophotovolta...
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Linearly Polarized Thermal Emitter for More Efficient Thermophotovoltaic Devices Ames ... than can be used to create more efficient thermophotovoltaic devices for power generation. ...
Resource-Efficient Generataion of Linear Cluster States by Linear Optics with postselection
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Uskov, Dmitry B; Alsing, Paul; Fanto, Michael; Kaplan, Lev; Kim, R; Szep, Atilla; Smith IV, Amos M
2015-01-01
We report on theoretical research in photonic cluster-state computing. Finding optimal schemes of generating non-classical photonic states is of critical importance for this field as physically implementable photon-photon entangling operations are currently limited to measurement-assisted stochastic transformations. A critical parameter for assessing the efficiency of such transformations is the success probability of a desired measurement outcome. At present there are several experimental groups that are capable of generating multi-photon cluster states carrying more than eight qubits. Separate photonic qubits or small clusters can be fused into a single cluster state by a probabilistic optical CZ gate conditioned on simultaneous detectionmore » of all photons with 1/9 success probability for each gate. This design mechanically follows the original theoretical scheme of cluster state generation proposed more than a decade ago by Raussendorf, Browne, and Briegel. The optimality of the destructive CZ gate in application to linear optical cluster state generation has not been analyzed previously. Our results reveal that this method is far from the optimal one. Employing numerical optimization we have identified that the maximal success probability of fusing n unentangled dual-rail optical qubits into a linear cluster state is equal to 1/2^n-1; an m-tuple of photonic Bell pair states, commonly generated via spontaneous parametric down-conversion, can be fused into a single cluster with the maximal success probability of 1/4^m-1.« less
Resource-Efficient Generataion of Linear Cluster States by Linear Optics with postselection
Uskov, Dmitry B; Alsing, Paul; Fanto, Michael; Kaplan, Lev; Kim, R; Szep, Atilla; Smith IV, Amos M
2015-01-01
We report on theoretical research in photonic cluster-state computing. Finding optimal schemes of generating non-classical photonic states is of critical importance for this field as physically implementable photon-photon entangling operations are currently limited to measurement-assisted stochastic transformations. A critical parameter for assessing the efficiency of such transformations is the success probability of a desired measurement outcome. At present there are several experimental groups that are capable of generating multi-photon cluster states carrying more than eight qubits. Separate photonic qubits or small clusters can be fused into a single cluster state by a probabilistic optical CZ gate conditioned on simultaneous detection of all photons with 1/9 success probability for each gate. This design mechanically follows the original theoretical scheme of cluster state generation proposed more than a decade ago by Raussendorf, Browne, and Briegel. The optimality of the destructive CZ gate in application to linear optical cluster state generation has not been analyzed previously. Our results reveal that this method is far from the optimal one. Employing numerical optimization we have identified that the maximal success probability of fusing n unentangled dual-rail optical qubits into a linear cluster state is equal to 1/2^n-1; an m-tuple of photonic Bell pair states, commonly generated via spontaneous parametric down-conversion, can be fused into a single cluster with the maximal success probability of 1/4^m-1.
Resource-efficient generation of linear cluster states by linear optics with postselection
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Uskov, D. B.; Alsing, P. M.; Fanto, M. L.; Kaplan, L.; Kim, R.; Szep, A.; Smith, A. M.
2015-01-30
Here we report on theoretical research in photonic cluster-state computing. Finding optimal schemes of generating non-classical photonic states is of critical importance for this field as physically implementable photon-photon entangling operations are currently limited to measurement-assisted stochastic transformations. A critical parameter for assessing the efficiency of such transformations is the success probability of a desired measurement outcome. At present there are several experimental groups that are capable of generating multi-photon cluster states carrying more than eight qubits. Separate photonic qubits or small clusters can be fused into a single cluster state by a probabilistic optical CZ gate conditioned on simultaneousmore » detection of all photons with 1/9 success probability for each gate. This design mechanically follows the original theoretical scheme of cluster state generation proposed more than a decade ago by Raussendorf, Browne, and Briegel. The optimality of the destructive CZ gate in application to linear optical cluster state generation has not been analyzed previously. Our results reveal that this method is far from the optimal one. Employing numerical optimization we have identified that the maximal success probability of fusing n unentangled dual-rail optical qubits into a linear cluster state is equal to 1/2n-1; an m-tuple of photonic Bell pair states, commonly generated via spontaneous parametric down-conversion, can be fused into a single cluster with the maximal success probability of 1/4m-1.« less
Variable-energy drift-tube linear accelerator
Swenson, Donald A.; Boyd, Jr., Thomas J.; Potter, James M.; Stovall, James E.
1984-01-01
A linear accelerator system includes a plurality of post-coupled drift-tubes wherein each post coupler is bistably positionable to either of two positions which result in different field distributions. With binary control over a plurality of post couplers, a significant accumlative effect in the resulting field distribution is achieved yielding a variable-energy drift-tube linear accelerator.
Drift tube suspension for high intensity linear accelerators
Liska, Donald J.; Schamaun, Roger G.; Clark, Donald C.; Potter, R. Christopher; Frank, Joseph A.
1982-01-01
The disclosure relates to a drift tube suspension for high intensity linear accelerators. The system comprises a series of box-sections girders independently adjustably mounted on a linear accelerator. A plurality of drift tube holding stems are individually adjustably mounted on each girder.
Drift tube suspension for high intensity linear accelerators
Liska, D.J.; Schamaun, R.G.; Clark, D.C.; Potter, R.C.; Frank, J.A.
1980-03-11
The disclosure relates to a drift tube suspension for high intensity linear accelerators. The system comprises a series of box-sections girders independently adjustably mounted on a linear accelerator. A plurality of drift tube holding stems are individually adjustably mounted on each girder.
Differentially pumped dual linear quadrupole ion trap mass spectrometer
Owen, Benjamin C.; Kenttamaa, Hilkka I.
2015-10-20
The present disclosure provides a new tandem mass spectrometer and methods of using the same for analyzing charged particles. The differentially pumped dual linear quadrupole ion trap mass spectrometer of the present disclose includes a combination of two linear quadrupole (LQIT) mass spectrometers with differentially pumped vacuum chambers.
Linear Concentrator System Basics for Concentrating Solar Power
Broader source: Energy.gov [DOE]
Linear concentrating solar power (CSP) collectors capture the sun's energy with large mirrors that reflect and focus the sunlight onto a linear receiver tube. The receiver contains a fluid that is heated by the sunlight and then used to heat a traditional power cycle that spins a turbine that drives a generator to produce electricity.
Variable-energy drift-tube linear accelerator
Swenson, D.A.; Boyd, T.J. Jr.; Potter, J.M.; Stovall, J.E.
A linear accelerator system includes a plurality of post-coupled drift-tubes wherein each post coupler is bistably positionable to either of two positions which result in different field distributions. With binary control over a plurality of post couplers, a significant accumlative effect in the resulting field distribution is achieved yielding a variable-energy drift-tube linear accelerator.
Comparison of open-source linear programming solvers.
Gearhart, Jared Lee; Adair, Kristin Lynn; Durfee, Justin D.; Jones, Katherine A.; Martin, Nathaniel; Detry, Richard Joseph
2013-10-01
When developing linear programming models, issues such as budget limitations, customer requirements, or licensing may preclude the use of commercial linear programming solvers. In such cases, one option is to use an open-source linear programming solver. A survey of linear programming tools was conducted to identify potential open-source solvers. From this survey, four open-source solvers were tested using a collection of linear programming test problems and the results were compared to IBM ILOG CPLEX Optimizer (CPLEX) [1], an industry standard. The solvers considered were: COIN-OR Linear Programming (CLP) [2], [3], GNU Linear Programming Kit (GLPK) [4], lp_solve [5] and Modular In-core Nonlinear Optimization System (MINOS) [6]. As no open-source solver outperforms CPLEX, this study demonstrates the power of commercial linear programming software. CLP was found to be the top performing open-source solver considered in terms of capability and speed. GLPK also performed well but cannot match the speed of CLP or CPLEX. lp_solve and MINOS were considerably slower and encountered issues when solving several test problems.
Nonlinear vs. linear biasing in Trp-cage folding simulations
Spiwok, Vojt?ch Oborsk, Pavel; Krlov, Blanka; Pazrikov, Jana
2015-03-21
Biased simulations have great potential for the study of slow processes, including protein folding. Atomic motions in molecules are nonlinear, which suggests that simulations with enhanced sampling of collective motions traced by nonlinear dimensionality reduction methods may perform better than linear ones. In this study, we compare an unbiased folding simulation of the Trp-cage miniprotein with metadynamics simulations using both linear (principle component analysis) and nonlinear (Isomap) low dimensional embeddings as collective variables. Folding of the mini-protein was successfully simulated in 200?ns simulation with linear biasing and non-linear motion biasing. The folded state was correctly predicted as the free energy minimum in both simulations. We found that the advantage of linear motion biasing is that it can sample a larger conformational space, whereas the advantage of nonlinear motion biasing lies in slightly better resolution of the resulting free energy surface. In terms of sampling efficiency, both methods are comparable.
Non-linear stochastic growth rates and redshift space distortions
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Jennings, Elise; Jennings, David
2015-04-09
The linear growth rate is commonly defined through a simple deterministic relation between the velocity divergence and the matter overdensity in the linear regime. We introduce a formalism that extends this to a non-linear, stochastic relation between θ = ∇ ∙ v(x,t)/aH and δ. This provides a new phenomenological approach that examines the conditional mean <θ|δ>, together with the fluctuations of θ around this mean. We also measure these stochastic components using N-body simulations and find they are non-negative and increase with decreasing scale from ~10 per cent at k < 0.2 h Mpc-1 to 25 per cent at kmore » ~ 0.45 h Mpc-1 at z = 0. Both the stochastic relation and non-linearity are more pronounced for haloes, M ≤ 5 × 1012 M⊙ h-1, compared to the dark matter at z = 0 and 1. Non-linear growth effects manifest themselves as a rotation of the mean <θ|δ> away from the linear theory prediction -fLTδ, where fLT is the linear growth rate. This rotation increases with wavenumber, k, and we show that it can be well-described by second-order Lagrangian perturbation theory (2LPT) fork < 0.1 h Mpc-1. Furthermore, the stochasticity in the θ – δ relation is not so simply described by 2LPT, and we discuss its impact on measurements of fLT from two-point statistics in redshift space. Furthermore, given that the relationship between δ and θ is stochastic and non-linear, this will have implications for the interpretation and precision of fLT extracted using models which assume a linear, deterministic expression.« less
Asynchronous parallel generating set search for linearly-constrained optimization.
Lewis, Robert Michael; Griffin, Joshua D.; Kolda, Tamara Gibson
2006-08-01
Generating set search (GSS) is a family of direct search methods that encompasses generalized pattern search and related methods. We describe an algorithm for asynchronous linearly-constrained GSS, which has some complexities that make it different from both the asynchronous bound-constrained case as well as the synchronous linearly-constrained case. The algorithm has been implemented in the APPSPACK software framework and we present results from an extensive numerical study using CUTEr test problems. We discuss the results, both positive and negative, and conclude that GSS is a reliable method for solving small-to-medium sized linearly-constrained optimization problems without derivatives.
Linear Scaling Electronic Structure Methods with Periodic Boundary Conditions
Gustavo E. Scuseria
2008-02-08
The methodological development and computational implementation of linear scaling quantum chemistry methods for the accurate calculation of electronic structure and properties of periodic systems (solids, surfaces, and polymers) and their application to chemical problems of DOE relevance.
Spin relaxation and linear-in-electric-field frequency shift...
Office of Scientific and Technical Information (OSTI)
arbitrary, time-independent magnetic field Citation Details In-Document Search Title: Spin relaxation and linear-in-electric-field frequency shift in an arbitrary, time-independen...
Linear Scaling of the Exciton Binding Energy versus the Band...
Office of Scientific and Technical Information (OSTI)
Linear Scaling of the Exciton Binding Energy versus the Band Gap of Two-Dimensional Materials This content will become publicly available on August 6, 2016 Prev Next Title:...
Linear and cubic response to the initial eccentricity in heavy...
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Linear and cubic response to the initial eccentricity in heavy-ion collisions Citation Details In-Document Search This content will become publicly available on January 21, 2017 ...
Method and apparatus of highly linear optical modulation
DeRose, Christopher; Watts, Michael R.
2016-05-03
In a new optical intensity modulator, a nonlinear change in refractive index is used to balance the nonlinearities in the optical transfer function in a way that leads to highly linear optical intensity modulation.
Physics Case for the International Linear Collider (Technical...
Office of Scientific and Technical Information (OSTI)
We summarize the physics case for the International Linear Collider (ILC). We review the ... in accord with the expected schedule of operation of the accelerator and the results of ...
Fourth order resonance of a high intensity linear accelerator...
Office of Scientific and Technical Information (OSTI)
For a high intensity beam, the 4nu1 resonance of a linear accelerator is manifested through the octupolar term of space charge potential when the depressed phase advance sigma ...
Linear Concentrator System Basics for Concentrating Solar Power...
may be integrated with existing or new combined-cycle natural-gas- and coal-fired plants. ... Illustration of a linear concentrator power plant using parabolic trough collectors. ...
International Linear Collider Technical Design Report - Volume 2: Physics
Office of Scientific and Technical Information (OSTI)
(Technical Report) | SciTech Connect International Linear Collider Technical Design Report - Volume 2: Physics Citation Details In-Document Search Title: International Linear Collider Technical Design Report - Volume 2: Physics Authors: Baer, Howard ; Barklow, Tim ; Fujii, Keisuke ; Gao, Yuanning ; Hoang, Andre ; Kanemura, Shinya ; List, Jenny ; Logan, Heather E. ; Nomerotski, Andrei ; Perelstein, Maxim ; Peskin, Michael E. ; Poschl, Roman ; Reuter, Jurgen ; Riemann, Sabine ; Savoy-Navarro,
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism Print Using spectroscopic information for magnetometry and magnetic microscopy obviously requires detailed theoretical understanding of spectral shape and magnitude of dichroism signals. A research team at ALS Beamline 4.0.2 has now shown unambiguously that, contrary to common belief, spectral shape and magnitude of x-ray magnetic linear dichroism (XMLD) are not only determined by the relative orientation of magnetic moments and
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism Print Using spectroscopic information for magnetometry and magnetic microscopy obviously requires detailed theoretical understanding of spectral shape and magnitude of dichroism signals. A research team at ALS Beamline 4.0.2 has now shown unambiguously that, contrary to common belief, spectral shape and magnitude of x-ray magnetic linear dichroism (XMLD) are not only determined by the relative orientation of magnetic moments and
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism Print Using spectroscopic information for magnetometry and magnetic microscopy obviously requires detailed theoretical understanding of spectral shape and magnitude of dichroism signals. A research team at ALS Beamline 4.0.2 has now shown unambiguously that, contrary to common belief, spectral shape and magnitude of x-ray magnetic linear dichroism (XMLD) are not only determined by the relative orientation of magnetic moments and
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism Print Using spectroscopic information for magnetometry and magnetic microscopy obviously requires detailed theoretical understanding of spectral shape and magnitude of dichroism signals. A research team at ALS Beamline 4.0.2 has now shown unambiguously that, contrary to common belief, spectral shape and magnitude of x-ray magnetic linear dichroism (XMLD) are not only determined by the relative orientation of magnetic moments and
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism Print Using spectroscopic information for magnetometry and magnetic microscopy obviously requires detailed theoretical understanding of spectral shape and magnitude of dichroism signals. A research team at ALS Beamline 4.0.2 has now shown unambiguously that, contrary to common belief, spectral shape and magnitude of x-ray magnetic linear dichroism (XMLD) are not only determined by the relative orientation of magnetic moments and
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism Print Wednesday, 29 August 2007 00:00 Using spectroscopic information for magnetometry and magnetic microscopy obviously requires detailed theoretical understanding of spectral shape and magnitude of dichroism signals. A research team at ALS Beamline 4.0.2 has now shown unambiguously that, contrary to common belief, spectral shape and magnitude of x-ray magnetic
JLab Supports International Linear Collider Cavity Development Work |
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Jefferson Lab Supports International Linear Collider Cavity Development Work JLab Supports International Linear Collider Cavity Development Work NEWPORT NEWS, Va. Feb. 12, 2008 - It's not often that major-league baseball and nuclear physics get to share the limelight, but that's what's happening at the Department of Energy's Jefferson Lab. The baseball connection involves a nine-cell niobium cavity developed by KEK accelerator scientists in Japan as one of several designs being tested for
Free piston variable-stroke linear-alternator generator
Haaland, Carsten M.
1998-01-01
A free-piston variable stroke linear-alternator AC power generator for a combustion engine. An alternator mechanism and oscillator system generates AC current. The oscillation system includes two oscillation devices each having a combustion cylinder and a flying turnbuckle. The flying turnbuckle moves in accordance with the oscillation device. The alternator system is a linear alternator coupled between the two oscillation devices by a slotted connecting rod.
Producing Linear Alpha Olefins From Biomass - Energy Innovation Portal
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Producing Linear Alpha Olefins From Biomass Great Lakes Bioenergy Research Center Contact GLBRC About This Technology Technology Marketing Summary Linear alpha olefins (LAOs) are valuable commodity chemicals traditionally derived from petroleum. They are versatile building blocks for making a range of chemical products like polyethylene, synthetic oils, plasticizers, detergents and oilfield fluids. Relying on fossil fuel to manufacture LAOs is problematic. Not only are the standard methods
Direct Probes of Linearly Polarized Gluons inside Unpolarized Hadrons
Boer, Daniel; Brodsky, Stanley J.; Mulders, Piet J.; Pisano, Cristian; /Cagliari U. /INFN, Cagliari
2011-02-07
We show that the unmeasured distribution of linearly polarized gluons inside unpolarized hadrons can be directly probed in jet or heavy quark pair production both in electron-hadron and hadron-hadron collisions. We present expressions for the simplest cos 2{phi} asymmetries and estimate their maximal value in the particular case of electron-hadron collisions. Measurements of the linearly polarized gluon distribution in the proton should be feasible in future EIC or LHeC experiments.
Accessing the Distribution of Linearly Polarized Gluons in Unpolarized Hadrons
Boer, Daniel; Brodsky, Stanley J.; Mulders, Piet J.; Pisano, Cristian; /Cagliari U. /INFN, Cagliari
2011-08-19
Gluons inside unpolarized hadrons can be linearly polarized provided they have a nonzero transverse momentum. The simplest and theoretically safest way to probe this distribution of linearly polarized gluons is through cos2{phi} asymmetries in heavy quark pair or dijet production in electron-hadron collisions. Future Electron-Ion Collider (EIC) or Large Hadron electron Collider (LHeC) experiments are ideally suited for this purpose. Here we estimate the maximum asymmetries for EIC kinematics.
DOE - Office of Legacy Management -- Stanford Linear Accelerator Center -
Office of Legacy Management (LM)
005 Stanford Linear Accelerator Center - 005 FUSRAP Considered Sites Site: Stanford Linear Accelerator Center (005) More information at www.slac.stanford.edu Designated Name: Not Designated under FUSRAP Alternate Name: SLAC Location: Palo Alto, California Evaluation Year: Not considered for FUSRAP - in another program Site Operations: Research Site Disposition: Remediation completed by DOE Office of Environmental Management in 2014. DOE Office of Science is responsible for long-term
Free piston variable-stroke linear-alternator generator
Haaland, C.M.
1998-12-15
A free-piston variable stroke linear-alternator AC power generator for a combustion engine is described. An alternator mechanism and oscillator system generates AC current. The oscillation system includes two oscillation devices each having a combustion cylinder and a flying turnbuckle. The flying turnbuckle moves in accordance with the oscillation device. The alternator system is a linear alternator coupled between the two oscillation devices by a slotted connecting rod. 8 figs.
Modeling patterns in data using linear and related models
Engelhardt, M.E.
1996-06-01
This report considers the use of linear models for analyzing data related to reliability and safety issues of the type usually associated with nuclear power plants. The report discusses some of the general results of linear regression analysis, such as the model assumptions and properties of the estimators of the parameters. The results are motivated with examples of operational data. Results about the important case of a linear regression model with one covariate are covered in detail. This case includes analysis of time trends. The analysis is applied with two different sets of time trend data. Diagnostic procedures and tests for the adequacy of the model are discussed. Some related methods such as weighted regression and nonlinear models are also considered. A discussion of the general linear model is also included. Appendix A gives some basic SAS programs and outputs for some of the analyses discussed in the body of the report. Appendix B is a review of some of the matrix theoretic results which are useful in the development of linear models.
Higher-degree linear approximations of nonlinear systems
Karahan, S.
1989-01-01
In this dissertation, the author develops a new method for obtaining higher degree linear approximations of nonlinear control systems. The standard approach in the analysis and synthesis of nonlinear systems is a first order approximation by a linear model. This is usually performed by obtaining a series expansion of the system at some nominal operating point and retaining only the first degree terms in the series. The accuracy of this approximation depends on how far the system moves away from the normal point, and on the relative magnitudes of the higher degree terms in the series expansion. The approximation is achieved by finding an appropriate nonlinear coordinate transformation-feedback pair to perform the higher degree linearization. With the proposed method, one can improve the accuracy of the approximation up to arbitrarily higher degrees, provided certain solvability conditions are satisfied. The Hunt-Su linearizability theorem makes these conditions precise. This approach is similar to Poincare's Normal Form Theorem in formulation, but different in its solution method. After some mathematical background the author derives a set of equations (called the Homological Equations). A solution to this system of linear equations is equivalent to the solution to the problem of approximate linearization. However, it is generally not possible to solve the system of equations exactly. He outlines a method for systematically finding approximate solutions to these equations using singular value decomposition, while minimizing an error with respect to some defined norm.
New non-linear photovoltaic effect in uniform bipolar semiconductor
Volovichev, I.
2014-11-21
A linear theory of the new non-linear photovoltaic effect in the closed circuit consisting of a non-uniformly illuminated uniform bipolar semiconductor with neutral impurities is developed. The non-uniform photo-excitation of impurities results in the position-dependant current carrier mobility that breaks the semiconductor homogeneity and induces the photo-electromotive force (emf). As both the electron (or hole) mobility gradient and the current carrier generation rate depend on the light intensity, the photo-emf and the short-circuit current prove to be non-linear functions of the incident light intensity at an arbitrarily low illumination. The influence of the sample size on the photovoltaic effect magnitude is studied. Physical relations and distinctions between the considered effect and the Dember and bulk photovoltaic effects are also discussed.
APPLICATION OF NEURAL NETWORK ALGORITHMS FOR BPM LINEARIZATION
Musson, John C.; Seaton, Chad; Spata, Mike F.; Yan, Jianxun
2012-11-01
Stripline BPM sensors contain inherent non-linearities, as a result of field distortions from the pickup elements. Many methods have been devised to facilitate corrections, often employing polynomial fitting. The cost of computation makes real-time correction difficult, particulalry when integer math is utilized. The application of neural-network technology, particularly the multi-layer perceptron algorithm, is proposed as an efficient alternative for electrode linearization. A process of supervised learning is initially used to determine the weighting coefficients, which are subsequently applied to the incoming electrode data. A non-linear layer, known as an ?activation layer,? is responsible for the removal of saturation effects. Implementation of a perceptron in an FPGA-based software-defined radio (SDR) is presented, along with performance comparisons. In addition, efficient calculation of the sigmoidal activation function via the CORDIC algorithm is presented.
Confirming the Lanchestrian linear-logarithmic model of attrition
Hartley, D.S. III.
1990-12-01
This paper is the fourth in a series of reports on the breakthrough research in historical validation of attrition in conflict. Significant defense policy decisions, including weapons acquisition and arms reduction, are based in part on models of conflict. Most of these models are driven by their attrition algorithms, usually forms of the Lanchester square and linear laws. None of these algorithms have been validated. The results of this paper confirm the results of earlier papers, using a large database of historical results. The homogeneous linear-logarithmic Lanchestrian attrition model is validated to the extent possible with current initial and final force size data and is consistent with the Iwo Jima data. A particular differential linear-logarithmic model is described that fits the data very well. A version of Helmbold's victory predicting parameter is also confirmed, with an associated probability function. 37 refs., 73 figs., 68 tabs.
Magnetic levitation configuration incorporating levitation, guidance and linear synchronous motor
Coffey, Howard T.
1993-01-01
A propulsion and suspension system for an inductive repulsion type magnetically levitated vehicle which is propelled and suspended by a system which includes propulsion windings which form a linear synchronous motor and conductive guideways, adjacent to the propulsion windings, where both combine to partially encircling the vehicle-borne superconducting magnets. A three phase power source is used with the linear synchronous motor to produce a traveling magnetic wave which in conjunction with the magnets propel the vehicle. The conductive guideway combines with the superconducting magnets to provide for vehicle leviation.
Magnetic levitation configuration incorporating levitation, guidance and linear synchronous motor
Coffey, H.T.
1993-10-19
A propulsion and suspension system for an inductive repulsion type magnetically levitated vehicle which is propelled and suspended by a system which includes propulsion windings which form a linear synchronous motor and conductive guideways, adjacent to the propulsion windings, where both combine to partially encircling the vehicle-borne superconducting magnets. A three phase power source is used with the linear synchronous motor to produce a traveling magnetic wave which in conjunction with the magnets propel the vehicle. The conductive guideway combines with the superconducting magnets to provide for vehicle levitation. 3 figures.
LDRD final report : autotuning for scalable linear algebra.
Heroux, Michael Allen; Marker, Bryan
2011-09-01
This report summarizes the progress made as part of a one year lab-directed research and development (LDRD) project to fund the research efforts of Bryan Marker at the University of Texas at Austin. The goal of the project was to develop new techniques for automatically tuning the performance of dense linear algebra kernels. These kernels often represent the majority of computational time in an application. The primary outcome from this work is a demonstration of the value of model driven engineering as an approach to accurately predict and study performance trade-offs for dense linear algebra computations.
Search for Linear Polarization of the Cosmic Background Radiation
DOE R&D Accomplishments [OSTI]
Lubin, P. M.; Smoot, G. F.
1978-10-01
We present preliminary measurements of the linear polarization of the cosmic microwave background (3 deg K blackbody) radiation. These ground-based measurements are made at 9 mm wavelength. We find no evidence for linear polarization, and set an upper limit for a polarized component of 0.8 m deg K with a 95% confidence level. This implies that the present rate of expansion of the Universe is isotropic to one part in 10{sup 6}, assuming no re-ionization of the primordial plasma after recombination
Linear-array ultrasonic waveguide transducer for under sodium viewing.
Sheen, S. H.; Chien, H. T.; Wang, K.; Lawrence, W. P.; Engel, D.; Nuclear Engineering Division
2010-09-01
In this report, we first present the basic design of a low-noise waveguide and its performance followed by a review of the array transducer technology. The report then presents the concept and basic designs of arrayed waveguide transducers that can apply to under-sodium viewing for in-service inspection of fast reactors. Depending on applications, the basic waveguide arrays consist of designs for sideway and downward viewing. For each viewing application, two array geometries, linear and circular, are included in design analysis. Methods to scan a 2-D target using a linear array waveguide transducer are discussed. Future plan to develop a laboratory array waveguide prototype is also presented.
Klystron switching power supplies for the Internation Linear Collider
Fraioli, Andrea; /Cassino U. /INFN, Pisa
2009-12-01
The International Linear Collider is a majestic High Energy Physics particle accelerator that will give physicists a new cosmic doorway to explore energy regimes beyond the reach of today's accelerators. ILC will complement the Large Hadron Collider (LHC), a proton-proton collider at the European Center for Nuclear Research (CERN) in Geneva, Switzerland, by producing electron-positron collisions at center of mass energy of about 500 GeV. In particular, the subject of this dissertation is the R&D for a solid state Marx Modulator and relative switching power supply for the International Linear Collider Main LINAC Radio Frequency stations.
Beamstrahlung spectra in next generation linear colliders. Revision
Barklow, T.; Chen, P.; Kozanecki, W.
1992-04-01
For the next generation of linear colliders, the energy loss due to beamstrahlung during the collision of the e{sup +}e{sup {minus}} beams is expected to substantially influence the effective center-of-mass energy distribution of the colliding particles. In this paper, we first derive analytical formulae for the electron and photon energy spectra under multiple beamstrahlung processes, and for the e{sup +}e{sup {minus}} and {gamma}{gamma} differential luminosities. We then apply our formulation to various classes of 500 GeV e{sup +}e{sup {minus}} linear collider designs currently under study.
Direct Probes of Linearly Polarized Gluons inside Unpolarized Hadrons
Boer, Danieel; Brodsky, Stanley J.; Mulders, Piet J.; Pisano, Cristian
2011-04-01
We show that linearly polarized gluons inside unpolarized hadrons can be directly probed in jet or heavy quark pair production in electron-hadron collisions. We discuss the simplest cos2{phi} asymmetries and estimate their maximal value, concluding that measurements of the unknown linearly polarized gluon distribution in the proton should be feasible in future Electron-Ion Collider or Large Hadron electron Collider experiments. Analogous asymmetries in hadron-hadron collisions suffer from factorization breaking contributions and would allow us to quantify the importance of initial- and final-state interactions.
LDRD final report on a unified linear reference system
Espinoza, J. Jr.; Mackoy, R.D.; Fletcher, D.R.
1997-06-01
The purpose of the project was to describe existing deficiencies in Geographic Information Systems for transportation (GIS-T) applications and prescribe solutions that would benefit the transportation community in general. After an in-depth literature search and much consultation with noted transportation experts, the need for a common linear reference system that integrated and supported the planning and operational needs of the transportation community became very apparent. The focus of the project was set on a unified linear reference system and how to go about its requirements definition, design, implementation, and promulgation to the transportation community.
Solving linear inequalities in a least squares sense
Bramley, R.; Winnicka, B.
1994-12-31
Let A {element_of} {Re}{sup mxn} be an arbitrary real matrix, and let b {element_of} {Re}{sup m} a given vector. A familiar problem in computational linear algebra is to solve the system Ax = b in a least squares sense; that is, to find an x* minimizing {parallel}Ax {minus} b{parallel}, where {parallel} {center_dot} {parallel} refers to the vector two-norm. Such an x* solves the normal equations A{sup T}(Ax {minus} b) = 0, and the optimal residual r* = b {minus} Ax* is unique (although x* need not be). The least squares problem is usually interpreted as corresponding to multiple observations, represented by the rows of A and b, on a vector of data x. The observations may be inconsistent, and in this case a solution is sought that minimizes the norm of the residuals. A less familiar problem to numerical linear algebraists is the solution of systems of linear inequalities Ax {le} b in a least squares sense, but the motivation is similar: if a set of observations places upper or lower bounds on linear combinations of variables, the authors want to find x* minimizing {parallel} (Ax {minus} b){sub +} {parallel}, where the i{sup th} component of the vector v{sub +} is the maximum of zero and the i{sup th} component of v.
SIMULTANEOUS LINEAR AND CIRCULAR OPTICAL POLARIMETRY OF ASTEROID (4) VESTA
Wiktorowicz, Sloane J.; Nofi, Larissa A.
2015-02-10
From a single 3.8 hr observation of the asteroid (4) Vesta at 13.7 phase angle with the POlarimeter at Lick for Inclination Studies of Hot jupiters 2 (POLISH2) at the Lick Observatory Shane 3 m telescope, we confirm rotational modulation of linear polarization in the B and V bands. We measure the peak-to-peak modulation in the degree of linear polarization to be ?P = (294 35) 10{sup ?6} (ppm) and time-averaged ?P/P = 0.0575 0.0069. After rotating the plane of linear polarization to the scattering plane, asteroidal rotational modulation is detected with 12? confidence and observed solely in Stokes Q/I. POLISH2 simultaneously measures Stokes I, Q, U (linear polarization), and V (circular polarization), but we detect no significant circular polarization with a 1? upper limit of 78 ppm in the B band. Circular polarization is expected to arise from multiple scattering of sunlight by rough surfaces, and it has previously been detected in nearly all other classes of solar system bodies except for asteroids. Subsequent observations may be compared with surface albedo maps from the Dawn Mission, which may allow the identification of compositional variation across the asteroidal surface. These results demonstrate the high accuracy achieved by POLISH2 at the Lick 3 m telescope, which is designed to directly detect scattered light from spatially unresolvable exoplanets.
Tunneling control using classical non-linear oscillator
Kar, Susmita; Bhattacharyya, S. P.
2014-04-24
A quantum particle is placed in symmetric double well potential which is coupled to a classical non-linear oscillator via a coupling function. With different spatial symmetry of the coupling and under various controlling fashions, the tunneling of the quantum particle can be enhanced or suppressed, or totally destroyed.
Position sensor for linear synchronous motors employing halbach arrays
Post, Richard Freeman
2014-12-23
A position sensor suitable for use in linear synchronous motor (LSM) drive systems employing Halbach arrays to create their magnetic fields is described. The system has several advantages over previously employed ones, especially in its simplicity and its freedom from being affected by weather conditions, accumulated dirt, or electrical interference from the LSM system itself.
Annular linear induction pump with an externally supported duct
Craig, Edwin R.; Semken, Robert S.
1979-01-01
Several embodiments of an annular linear induction pump for pumping liquid metals are disclosed having the features of generally one pass flow of the liquid metal through the pump and an increased efficiency resulting from the use of thin duct walls to enclose the stator. The stator components of this pump are removable for repair and replacement.
Scalable Library for the Parallel Solution of Sparse Linear Systems
Energy Science and Technology Software Center (OSTI)
1993-07-14
BlockSolve is a scalable parallel software library for the solution of large sparse, symmetric systems of linear equations. It runs on a variety of parallel architectures and can easily be ported to others. BlockSovle is primarily intended for the solution of sparse linear systems that arise from physical problems having multiple degrees of freedom at each node point. For example, when the finite element method is used to solve practical problems in structural engineering, eachmore » node will typically have anywhere from 3-6 degrees of freedom associated with it. BlockSolve is written to take advantage of problems of this nature; however, it is still reasonably efficient for problems that have only one degree of freedom associated with each node, such as the three-dimensional Poisson problem. It does not require that the matrices have any particular structure other than being sparse and symmetric. BlockSolve is intended to be used within real application codes. It is designed to work best in the context of our experience which indicated that most application codes solve the same linear systems with several different right-hand sides and/or linear systems with the same structure, but different matrix values multiple times.« less
Translation and integration of numerical atomic orbitals in linear molecules
Heinäsmäki, Sami
2014-02-14
We present algorithms for translation and integration of atomic orbitals for LCAO calculations in linear molecules. The method applies to arbitrary radial functions given on a numerical mesh. The algorithms are based on pseudospectral differentiation matrices in two dimensions and the corresponding two-dimensional Gaussian quadratures. As a result, multicenter overlap and Coulomb integrals can be evaluated effectively.
Introduction to Control Theory. Part 2. Laplace Transforms and Linear Systems
Scheinker, Alexander
2015-09-11
Presentation for summer students. Start by considering linear differential equations, and how to solve them. The Laplace Transform is a great tool for solving linear differential equations.
FPGA-based Klystron linearization implementations in scope of ILC
Omet, M.; Michizono, S.; Varghese, P.; Schlarb, H.; Branlard, J.; Cichalewski, W.
2015-01-23
We report the development and implementation of four FPGA-based predistortion-type klystron linearization algorithms. Klystron linearization is essential for the realization of ILC, since it is required to operate the klystrons 7% in power below their saturation. The work presented was performed in international collaborations at the Fermi National Accelerator Laboratory (FNAL), USA and the Deutsches Elektronen Synchrotron (DESY), Germany. With the newly developed algorithms, the generation of correction factors on the FPGA was improved compared to past algorithms, avoiding quantization and decreasing memory requirements. At FNAL, three algorithms were tested at the Advanced Superconducting Test Accelerator (ASTA), demonstrating a successful implementation for one algorithm and a proof of principle for two algorithms. Furthermore, the functionality of the algorithm implemented at DESY was demonstrated successfully in a simulation.
Surface wave and linear operating mode of a plasma antenna
Bogachev, N. N. Bogdankevich, I. L.; Gusein-zade, N. G.; Rukhadze, A. A.
2015-10-15
The relation between the propagation conditions of a surface electromagnetic wave along a finiteradius plasma cylinder and the linear operating mode of a plasma antenna is investigated. The solution to the dispersion relation for a surface wave propagating along a finite-radius plasma cylinder is analyzed for weakly and strongly collisional plasmas. Computer simulations of an asymmetrical plasma dipole antenna are performed using the KARAT code, wherein the dielectric properties of plasma are described in terms of the Drude model. The plasma parameters corresponding to the linear operating mode of a plasma antenna are determined. It is demonstrated that the characteristics of the plasma antenna in this mode are close to those of an analogous metal antenna.
Scalar mesons in three-flavor linear sigma models
Deirdre Black; Amir H. Fariborz; Sherif Moussa; Salah Nasri; Joseph Schrechter
2001-09-01
The three flavor linear sigma model is studied in order to understand the role of possible light scalar mesons in the pi-pi, pi-K and pi-eta elastic scattering channels. The K-matrix prescription is used to unitarize tree-level amplitudes and, with a sufficiently general model, we obtain reasonable ts to the experimental data. The effect of unitarization is very important and leads to the emergence of a nonet of light scalars, with masses below 1 GeV. We compare with a scattering treatment using a more general non-linear sigma model approach and also comment upon how our results t in with the scalar meson puzzle. The latter involves a preliminary investigation of possible mixing between scalar nonets.
FPGA-based Klystron linearization implementations in scope of ILC
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Omet, M.; Michizono, S.; Matsumoto, T.; Miura, T.; Qiu, F.; Chase, B.; Varghese, P.; Schlarb, H.; Branlard, J.; Cichalewski, W.
2015-01-23
We report the development and implementation of four FPGA-based predistortion-type klystron linearization algorithms. Klystron linearization is essential for the realization of ILC, since it is required to operate the klystrons 7% in power below their saturation. The work presented was performed in international collaborations at the Fermi National Accelerator Laboratory (FNAL), USA and the Deutsches Elektronen Synchrotron (DESY), Germany. With the newly developed algorithms, the generation of correction factors on the FPGA was improved compared to past algorithms, avoiding quantization and decreasing memory requirements. At FNAL, three algorithms were tested at the Advanced Superconducting Test Accelerator (ASTA), demonstrating a successfulmore » implementation for one algorithm and a proof of principle for two algorithms. Furthermore, the functionality of the algorithm implemented at DESY was demonstrated successfully in a simulation.« less
Experimental Evaluation of the Free Piston Engine - Linear Alternator (FPLA).
Leick, Michael T.; Moses, Ronald W.
2015-03-01
This report describes the experimental evaluation of a prototype free piston engine - linear alternator (FPLA) system developed at Sandia National Laboratories. The opposed piston design wa developed to investigate its potential for use in hybrid electric vehicles (HEVs). The system is mechanically simple with two - stroke uniflow scavenging for gas exchange and timed port fuel injection for fuel delivery, i.e. no complex valving. Electrical power is extracted from piston motion through linear alternators wh ich also provide a means for passive piston synchronization through electromagnetic coupling. In an HEV application, this electrical power would be used to charge the batteries. The engine - alternator system was designed, assembled and operated over a 2 - year period at Sandia National Laboratories in Livermore, CA. This report primarily contains a description of the as - built system, modifications to the system to enable better performance, and experimental results from start - up, motoring, and hydrogen combus tion tests.
When linear stability does not exclude nonlinear instability
Kevrekidis, P. G.; Pelinovsky, D. E.; Saxena, A.
2015-05-29
We describe a mechanism that results in the nonlinear instability of stationary states even in the case where the stationary states are linearly stable. In this study, this instability is due to the nonlinearity-induced coupling of the linearization’s internal modes of negative energy with the continuous spectrum. In a broad class of nonlinear Schrödinger equations considered, the presence of such internal modes guarantees the nonlinear instability of the stationary states in the evolution dynamics. To corroborate this idea, we explore three prototypical case examples: (a) an antisymmetric soliton in a double-well potential, (b) a twisted localized mode in a one-dimensional lattice with cubic nonlinearity, and (c) a discrete vortex in a two-dimensional saturable lattice. In all cases, we observe a weak nonlinear instability, despite the linear stability of the respective states.
Finite element analyses of a linear-accelerator electron gun
Iqbal, M. E-mail: muniqbal@ihep.ac.cn; Wasy, A.; Islam, G. U.; Zhou, Z.
2014-02-15
Thermo-structural analyses of the Beijing Electron-Positron Collider (BEPCII) linear-accelerator, electron gun, were performed for the gun operating with the cathode at 1000 °C. The gun was modeled in computer aided three-dimensional interactive application for finite element analyses through ANSYS workbench. This was followed by simulations using the SLAC electron beam trajectory program EGUN for beam optics analyses. The simulations were compared with experimental results of the assembly to verify its beam parameters under the same boundary conditions. Simulation and test results were found to be in good agreement and hence confirmed the design parameters under the defined operating temperature. The gun is operating continuously since commissioning without any thermal induced failures for the BEPCII linear accelerator.
Linear corotation torques in non-barotropic disks
Tsang, David
2014-02-20
A fully analytic expression for the linear corotation torque to first order in eccentricity for planets in non-barotropic protoplanetary disks is derived, taking into account the effect of disk entropy gradients. This torque formula is applicable to both the co-orbital, corotation torques and the non-co-orbital, corotation torques—for planets in orbits with non-zero eccentricity—in disks where the thermal diffusivity and viscosity are sufficient to maintain the linearity of these interactions. While the co-orbital, corotation torque is important for migration of planets in Type I migration, the non-co-orbital, corotation torque plays an important role in the eccentricity evolution of giant planets that have opened gaps in the disk. The presence of an entropy gradient in the disk can significantly modify the corotation torque in both these cases.
When linear stability does not exclude nonlinear instability
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Kevrekidis, P. G.; Pelinovsky, D. E.; Saxena, A.
2015-05-29
We describe a mechanism that results in the nonlinear instability of stationary states even in the case where the stationary states are linearly stable. In this study, this instability is due to the nonlinearity-induced coupling of the linearization’s internal modes of negative energy with the continuous spectrum. In a broad class of nonlinear Schrödinger equations considered, the presence of such internal modes guarantees the nonlinear instability of the stationary states in the evolution dynamics. To corroborate this idea, we explore three prototypical case examples: (a) an antisymmetric soliton in a double-well potential, (b) a twisted localized mode in a one-dimensionalmore » lattice with cubic nonlinearity, and (c) a discrete vortex in a two-dimensional saturable lattice. In all cases, we observe a weak nonlinear instability, despite the linear stability of the respective states.« less
Planning under uncertainty solving large-scale stochastic linear programs
Infanger, G. . Dept. of Operations Research Technische Univ., Vienna . Inst. fuer Energiewirtschaft)
1992-12-01
For many practical problems, solutions obtained from deterministic models are unsatisfactory because they fail to hedge against certain contingencies that may occur in the future. Stochastic models address this shortcoming, but up to recently seemed to be intractable due to their size. Recent advances both in solution algorithms and in computer technology now allow us to solve important and general classes of practical stochastic problems. We show how large-scale stochastic linear programs can be efficiently solved by combining classical decomposition and Monte Carlo (importance) sampling techniques. We discuss the methodology for solving two-stage stochastic linear programs with recourse, present numerical results of large problems with numerous stochastic parameters, show how to efficiently implement the methodology on a parallel multi-computer and derive the theory for solving a general class of multi-stage problems with dependency of the stochastic parameters within a stage and between different stages.
Power Saving Optimization for Linear Collider Interaction Region Parameters
Seryi, Andrei; /SLAC
2009-10-30
Optimization of Interaction Region parameters of a TeV energy scale linear collider has to take into account constraints defined by phenomena such as beam-beam focusing forces, beamstrahlung radiation, and hour-glass effect. With those constraints, achieving a desired luminosity of about 2E34 would require use of e{sup +}e{sup -} beams with about 10 MW average power. Application of the 'travelling focus' regime may allow the required beam power to be reduced by at least a factor of two, helping reduce the cost of the collider, while keeping the beamstrahlung energy loss reasonably low. The technique is illustrated for the 500 GeV CM parameters of the International Linear Collider. This technique may also in principle allow recycling the e{sup +}e{sup -} beams and/or recuperation of their energy.
SAR processing with non-linear FM chirp waveforms.
Doerry, Armin Walter
2006-12-01
Nonlinear FM (NLFM) waveforms offer a radar matched filter output with inherently low range sidelobes. This yields a 1-2 dB advantage in Signal-to-Noise Ratio over the output of a Linear FM (LFM) waveform with equivalent sidelobe filtering. This report presents details of processing NLFM waveforms in both range and Doppler dimensions, with special emphasis on compensating intra-pulse Doppler, often cited as a weakness of NLFM waveforms.
New timing system for the Stanford Linear Collider
Paffrath, L.; Bernstein, D.; Kang, H.; Koontz, R.; Leger, G.; Ross, M.; Pierce, W.; Wilmunder, A.
1984-11-01
In order to be able to meet the goals of the Stanford Linear Collider, a much more precise timing system had to be implemented. This paper describes the specification and design of this system, and the results obtained from its use on 1/3 of the SLAC linac. The functions of various elements are described, and a programmable delay unit (PDU) is described in detail.
Linear Fresnel Technology added to System Advisor Model's Capabilities -
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
News Releases | NREL Linear Fresnel Technology added to System Advisor Model's Capabilities Now utilities can get detailed information on siting, performance and finances February 8, 2012 A promising Concentrating Solar Power (CSP) technology that uses a stationary receiver tube and an array of mirrors mounted near the ground can now be accessed within the System Advisor Model (SAM), which predicts annual energy production, hourly performance and return on investment. The U.S. Department of
LINEAR SCANNING METHOD BASED ON THE SAFT COARRAY
Martin, C. J.; Martinez-Graullera, O.; Romero, D.; Ullate, L. G.; Higuti, R. T.
2010-02-22
This work presents a method to obtain B-scan images based on linear array scanning and 2R-SAFT. Using this technique some advantages are obtained: the ultrasonic system is very simple; it avoids the grating lobes formation, characteristic in conventional SAFT; and subaperture size and focussing lens (to compensate emission-reception) can be adapted dynamically to every image point. The proposed method has been experimentally tested in the inspection of CFRP samples.
Linearity of Climate Response to Increases in Black Carbon Aerosols
Mahajan, Salil; Evans, Katherine J.; Hack, James J.; Truesdale, John
2013-04-19
The impact of absorbing aerosols on global climate are not completely understood. Here, we present results of idealized experiments conducted with the Community Atmosphere Model (CAM4) coupled to a slab ocean model (CAM4-SOM) to simulate the climate response to increases in tropospheric black carbon aerosols (BC) by direct and semi-direct effects. CAM4-SOM was forced with 0, 1x, 2x, 5x and 10x an estimate of the present day concentration of BC while maintaining their estimated present day global spatial and vertical distribution. The top of the atmosphere (TOA) radiative forcing of BC in these experiments is positive (warming) and increases linearly as the BC burden increases. The total semi-direct effect for the 1x experiment is positive but becomes increasingly negative for higher BC concentrations. The global average surface temperature response is found to be a linear function of the TOA radiative forcing. The climate sensitivity to BC from these experiments is estimated to be 0.42 K $ W^{-1} m^{2}$ when the semi-direct effects are accounted for and 0.22 K $ W^{-1} m^{2}$ with only the direct effects considered. Global average precipitation decreases linearly as BC increases, with a precipitation sensitivity to atmospheric absorption of 0.4 $\\%$ $W^{-1}m^{2}$ . The hemispheric asymmetry of BC also causes an increase in southward cross-equatorial heat transport and a resulting northward shift of the inter-tropical convergence zone in the simulations at a rate of 4$^{\\circ}$N $ PW^{-1}$. Global average mid- and high-level clouds decrease, whereas the low-level clouds increase linearly with BC. The increase in marine stratocumulus cloud fraction over the south tropical Atlantic is caused by increased BC-induced diabatic heating of the free troposphere.
Radio-frequency quadrupole resonator for linear accelerator
Moretti, A.
1982-10-19
An RFQ resonator for a linear accelerator having a reduced level of interfering modes and producing a quadrupole mode for focusing, bunching and accelerating beams of heavy charged particles, with the construction being characterized by four elongated resonating rods within a cylinder with the rods being alternately shorted and open electrically to the shell at common ends of the rods to provide an LC parallel resonant circuit when activated by a magnetic field transverse to the longitudinal axis.
Linear induction accelerator and pulse forming networks therefor
Buttram, Malcolm T.; Ginn, Jerry W.
1989-01-01
A linear induction accelerator includes a plurality of adder cavities arranged in a series and provided in a structure which is evacuated so that a vacuum inductance is provided between each adder cavity and the structure. An energy storage system for the adder cavities includes a pulsed current source and a respective plurality of bipolar converting networks connected thereto. The bipolar high-voltage, high-repetition-rate square pulse train sets and resets the cavities.
Linear plasmoid instability of thin current sheets with shear flow
Ni Lei; Germaschewski, Kai; Huang Yimin; Sullivan, Brian P.; Yang Hongang; Bhattacharjee, Amitava
2010-05-15
This paper presents linear analytical and numerical studies of plasmoid instabilities in the presence of shear flow in high-Lundquist-number plasmas. Analysis demonstrates that the stability problem becomes essentially two dimensional as the stabilizing effects of shear flow become more prominent. Scaling results are presented for the two-dimensional instabilities. An approximate criterion is given for the critical aspect ratio of thin current sheets at which the plasmoid instability is triggered.
Parameter spaces for linear and nonlinear whistler-mode waves
Summers, Danny; School of Space Research, Kyung Hee University, Yongin, Gyeonggi ; Tang, Rongxin; Institute of Space Science and Technology, Nanchang University, Nanchang; State Key Laboratory of Space Weather, Chinese Academy of Sciences, Beijing ; Omura, Yoshiharu; Lee, Dong-Hun
2013-07-15
We examine the growth of magnetospheric whistler-mode waves which comprises a linear growth phase followed by a nonlinear growth phase. We construct time-profiles for the wave amplitude that smoothly match at the transition between linear and nonlinear wave growth. This matching procedure can only take place over a limited “matching region” in (N{sub h}/N{sub 0},A{sub T})-space, where A{sub T} is the electron thermal anisotropy, N{sub h} is the hot (energetic) electron number density, and N{sub 0} is the cold (background) electron number density. We construct this matching region and determine how the matching wave amplitude varies throughout the region. Further, we specify a boundary in (N{sub h}/N{sub 0},A{sub T})-space that separates a region where only linear chorus wave growth can occur from the region in which fully nonlinear chorus growth is possible. We expect that this boundary should prove of practical use in performing computationally expensive full-scale particle simulations, and in interpreting experimental wave data.
Linear response of tripartite entanglement to infinitesimal noise
Zhang, Fu-Lin; Chen, Jing-Ling
2014-10-15
Recent experimental progress in prolonging the coherence time of a quantum system prompts us to explore the behavior of quantum entanglement at the beginning of the decoherence process. The response of the entanglement under an infinitesimal noise can serve as a signature of the robustness of entangled states. A crucial problem of this topic in multipartite systems is to compute the degree of entanglement in a mixed state. We find a family of global noise in three-qubit systems, which is composed of four W states. Under its influence, the linear response of the tripartite entanglement of a symmetrical three-qubit pure state is studied. A lower bound of the linear response is found to depend completely on the initial tripartite and bipartite entanglement. This result shows that the decay of tripartite entanglement is hastened by the bipartite one. - Highlights: We study a set of W-type noise and its linear effect on symmetric pure states. Its effect on two-qubit entanglement depends only on the initial concurrence. A lower bound of the effect on 3-tangle is found in terms of initial entanglements. We obtain the time of three-tangle sudden death for two families of typical states. These reveal that the bipartite entanglement speeds up the decay of the tripartite one.
Johnson, Paul A; Tencate, James A; Le Bas, Pierre-Yves; Guyer, Robert; Vu, Cung Khac; Skelt, Christopher
2013-11-05
In some aspects of the disclosure, a method and an apparatus is disclosed for investigating material surrounding the borehole. The method includes generating a first low frequency acoustic wave within the borehole, wherein the first low frequency acoustic wave induces a linear and a nonlinear response in one or more features in the material that are substantially perpendicular to a radius of the borehole; directing a first sequence of high frequency pulses in a direction perpendicularly with respect to the longitudinal axis of the borehole into the material contemporaneously with the first acoustic wave; and receiving one or more second high frequency pulses at one or more receivers positionable in the borehole produced by an interaction between the first sequence of high frequency pulses and the one or more features undergoing linear and nonlinear elastic distortion due to the first low frequency acoustic wave to investigate the material surrounding the borehole.
Noiseless Vlasov–Poisson simulations with linearly transformed particles
Campos Pinto, Martin; Sonnendrücker, Eric; Friedman, Alex; Grote, David P.; Lund, Steve M.
2014-10-15
We introduce a deterministic discrete-particle simulation approach, the Linearly-Transformed Particle-In-Cell (LTPIC) method, that employs linear deformations of the particles to reduce the noise traditionally associated with particle schemes. Formally, transforming the particles is justified by local first order expansions of the characteristic flow in phase space. In practice the method amounts of using deformation matrices within the particle shape functions; these matrices are updated via local evaluations of the forward numerical flow. Because it is necessary to periodically remap the particles on a regular grid to avoid excessively deforming their shapes, the method can be seen as a development of Denavit's Forward Semi-Lagrangian (FSL) scheme (Denavit, 1972 [8]). However, it has recently been established (Campos Pinto, 2012 [20]) that the underlying Linearly-Transformed Particle scheme converges for abstract transport problems, with no need to remap the particles; deforming the particles can thus be seen as a way to significantly lower the remapping frequency needed in the FSL schemes, and hence the associated numerical diffusion. To couple the method with electrostatic field solvers, two specific charge deposition schemes are examined, and their performance compared with that of the standard deposition method. Finally, numerical 1d1v simulations involving benchmark test cases and halo formation in an initially mismatched thermal sheet beam demonstrate some advantages of our LTPIC scheme over the classical PIC and FSL methods. Benchmarked test cases also indicate that, for numerical choices involving similar computational effort, the LTPIC method is capable of accuracy comparable to or exceeding that of state-of-the-art, high-resolution Vlasov schemes.
PERVASIVE LINEAR POLARIZATION SIGNALS IN THE QUIET SUN
Bellot Rubio, L. R.; Orozco Suarez, D.
2012-09-20
This paper investigates the distribution of linear polarization signals in the quiet-Sun internetwork using ultra-deep spectropolarimetric data. We reduce the noise of the observations as much as is feasible by adding single-slit measurements of the Zeeman-sensitive Fe I 630 nm lines taken by the Hinode spectropolarimeter. The integrated Stokes spectra are employed to determine the fraction of the field of view covered by linear polarization signals. We find that up to 69% of the quiet solar surface at disk center shows Stokes Q or U profiles with amplitudes larger than 0.032% (4.5 times the noise level of 7 Multiplication-Sign 10{sup -5} reached by the longer integrations). The mere presence of linear polarization in most of the quiet Sun implies that the weak internetwork fields must be highly inclined, but we quantify this by inverting those pixels with Stokes Q or U signals well above the noise. This allows for a precise determination of the field inclination, field strength, and field azimuth because the information carried by all four Stokes spectra is used simultaneously. The inversion is performed for 53% of the observed field of view at a noise level of 1.3 Multiplication-Sign 10{sup -4} I{sub c}. The derived magnetic distributions are thus representative of more than half of the quiet-Sun internetwork. Our results confirm the conclusions drawn from previous analyses using mainly Stokes I and V: internetwork fields are very inclined, but except in azimuth they do not seem to be isotropically distributed.
Linear accelerators for TeV colliders. Revision
Wilson, P.B.
1985-10-01
The basic scaling relations for important linear collider design parameters are introduced. Some of the basic concepts concerning the design of accelerating structures are presented, and breakdown limitations are discussed. Rf power sources are considered. Some of the key concepts of wakefield accelerators are discussed, and some examples of wake fields for typical linac structures are presented. Some general concepts concerning emittance, and the limitations on the emittance that can be obtained from linac guns and damping rings are discussed. 49 refs., 15 figs. (LEW)
Beam Dynamics Design and Simulation in Ion Linear Accelerators (
Energy Science and Technology Software Center (OSTI)
2006-08-01
Orginally, the ray tracing code TRACK has been developed to fulfill the many special requirements for the Rare Isotope Accelerator Facility known as RIA. Since no available beam-dynamics code met all the necessary requirements, modifications to the code TRACK were introduced to allow end-to-end (from the ion souce to the production target) simulations of the RIA machine, TRACK is a general beam-dynamics code and can be applied for the design, commissioning and operation of modernmore » ion linear accelerators and beam transport systems.« less
Physics at the e⁺e⁻ linear collider
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Moortgat-Picka, G.; Kronfeld, A. S.
2015-08-14
A comprehensive review of physics at an e⁺e⁻ linear collider in the energy range of √s = 92 GeV–3 TeV is presented in view of recent and expected LHC results, experiments from low-energy as well as astroparticle physics. The report focuses in particular on Higgs-boson, top-quark and electroweak precision physics, but also discusses several models of beyond the standard model physics such as supersymmetry, little Higgs models and extra gauge bosons. The connection to cosmology has been analysed as well.
Physics at the e?e? linear collider
Moortgat-Picka, G.; Kronfeld, A. S.
2015-08-14
A comprehensive review of physics at an e?e? linear collider in the energy range of ?s = 92 GeV3 TeV is presented in view of recent and expected LHC results, experiments from low-energy as well as astroparticle physics. The report focuses in particular on Higgs-boson, top-quark and electroweak precision physics, but also discusses several models of beyond the standard model physics such as supersymmetry, little Higgs models and extra gauge bosons. The connection to cosmology has been analysed as well.
A RECIPE FOR LINEAR COLLIDER FINAL FOCUS SYSTEM DESIGN
Seryi, Andrei
2003-05-27
The design of Final Focus systems for linear colliders is challenging because of the large demagnifications needed to produce nanometer-sized beams at the interaction point. Simple first- and second-order matrix matching have proven insufficient for this task, and minimization of third- and higher-order aberrations is essential. An appropriate strategy is required for the latter to be successful. A recipe for Final Focus design, and a set of computational tools used to implement this approach, are described herein. An example of the use of this procedure is given.
Two linear time, low overhead algorithms for graph layout
Energy Science and Technology Software Center (OSTI)
2008-01-10
The software comprises two algorithms designed to perform a 2D layout of a graph structure in time linear with respect to the vertices and edges in the graph, whereas most other layout algorithms have a running time that is quadratic with respect to the number of vertices or greater. Although these layout algorithms run in a fraction of the time as their competitors, they provide competitive results when applied to most real-world graphs. These algorithmsmore » also have a low constant running time and small memory footprint, making them useful for small to large graphs.« less
A superconducting focusing solenoid for the neutrino factory linear accelerator
M.A. Green; V. Lebedev; B.R. Strauss
2002-03-01
The proposed superconducting linear accelerator that accelerates muons from 190 MeV to 2.45 GeV will use superconducting solenoids for focusing the muon beam. The accelerator will use superconducting RF cavities. These cavities are very sensitive to stay magnetic field from the focusing magnets. Superconducting solenoids can have large stray fields. This paper describes the 201.25-MHz acceleration system for the neutrino factory. This paper also describes a focusing solenoid that delivers almost no stray field to a neighboring superconducting RF cavity.
Mechanical features of the ATS RFQ linear accelerator
Wilson, N.G.; Hayward, T.D.; Lind, G.W.
1983-01-01
A radio-frequency quadrupole (RFQ) linear accelerator has been constructed and placed in operation on the Los Alamos National Laboratory accelerator test stand (ATS). This accelerator uses an evacuated rf manifold to distribute rf excitation from the 425-MHz rf power supply to the slot-coupled, RFQ vane-cavity, resonator assembly. The RFQ vanes are supported on commercially available copper-plated, linear, resilient C-seals to provide a high-conductivity rf contact that permits aligning and positioning the vanes during tuning, and demounting the vanes for evaluation and modification as necessary. All rf structures are fabricated from stress-relieved, bright-acid copper-plated carbon steel. Measurements made on the accelerator as assembled have demonstrated >8000 vane-cavity Q at the quadrupole's approx. 423.400-MHz accelerating-mode frequency. Operating manifold vacuum of 3 to 6 x 10/sup -8/ torr has been observed after rf conditioning; conditioning required 150 h for stable high-power rf operation. Experience to date has indicated the desirability of modifying the vane rf-contact seat configuration to improve assembly and alignment procedures, improving vane-machining processes to increase vane straightness, installing periodic vane-shorting rings to minimize the effect of dipole modes in the quadrupole accelerating structure,and modifying the waveguide-coupling slot in the manifold to improve forward rf power flow.
Exact linearized Coulomb collision operator in the moment expansion
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Ji, Jeong -Young; Held, Eric D.
2006-10-05
In the moment expansion, the Rosenbluth potentials, the linearized Coulomb collision operators, and the moments of the collision operators are analytically calculated for any moment. The explicit calculation of Rosenbluth potentials converts the integro-differential form of the Coulomb collision operator into a differential operator, which enables one to express the collision operator in a simple closed form for any arbitrary mass and temperature ratios. In addition, it is shown that gyrophase averaging the collision operator acting on arbitrary distribution functions is the same as the collision operator acting on the corresponding gyrophase averaged distribution functions. The moments of the collisionmore » operator are linear combinations of the fluid moments with collision coefficients parametrized by mass and temperature ratios. Furthermore, useful forms involving the small mass-ratio approximation are easily found since the collision operators and their moments are expressed in terms of the mass ratio. As an application, the general moment equations are explicitly written and the higher order heat flux equation is derived.« less
Practical application of equivalent linearization approaches to nonlinear piping systems
Park, Y.J.; Hofmayer, C.H.
1995-05-01
The use of mechanical energy absorbers as an alternative to conventional hydraulic and mechanical snubbers for piping supports has attracted a wide interest among researchers and practitioners in the nuclear industry. The basic design concept of energy absorbers (EA) is to dissipate the vibration energy of piping systems through nonlinear hysteretic actions of EA!s under design seismic loads. Therefore, some type of nonlinear analysis needs to be performed in the seismic design of piping systems with EA supports. The equivalent linearization approach (ELA) can be a practical analysis tool for this purpose, particularly when the response approach (RSA) is also incorporated in the analysis formulations. In this paper, the following ELA/RSA methods are presented and compared to each other regarding their practice and numerical accuracy: Response approach using the square root of sum of squares (SRSS) approximation (denoted RS in this paper). Classical ELA based on modal combinations and linear random vibration theory (denoted CELA in this paper). Stochastic ELA based on direct solution of response covariance matrix (denoted SELA in this paper). New algorithms to convert response spectra to the equivalent power spectral density (PSD) functions are presented for both the above CELA and SELA methods. The numerical accuracy of the three EL are studied through a parametric error analysis. Finally, the practicality of the presented analysis is demonstrated in two application examples for piping systems with EA supports.
Application of GIS in siting of linear facilities
Gallagher, G.A. III; Heatwole, D.W.; Schmidt, J.A. )
1993-01-01
Geographic information systems (GIS) are powerful tools in the analysis and selection of environmentally acceptable corridors for linear facilities, such as roads and utility lines. GIS can serve several functions in corridor siting, including managing and manipulating extensive environmental databases, weighting and compositing data layers to enable spatial analysis for a path of least resistance,'' summarizing statistics for a comparison of alternative corridors, preparing color graphics for presentations and reports, and providing a record of alternative analysis for permitting reviews and legal challenges. In this paper, the authors examine the benefits and limitations of using GIS to site linear facilities, based mainly on their experience in siting a 600-mile natural gas pipeline in Florida. They implemented a phased analytical approach to define acceptable corridors several miles in width and then selected viable routes within the corridors using a magnified scale. This approach resulted in a dynamic siting process which required numerous iterations of analysis. Consequently, their experience has instilled the benefits derived by expending preliminary effort to create macros of the GIS analytical process so that subsequent effort is minimized during numerous iterations of corridor and route refinement.
Linearized Boltzmann collision integral with the correct cutoff
Chang, Yongbin; White, R. D.
2014-07-15
In the calculation of the linearized Boltzmann collision operator for an inverse-square force law interaction (Coulomb interaction) F(r)=κ/r{sup 2}, we found the widely used scattering angle cutoff θ≥θ{sub min} is a wrong practise since the divergence still exists after the cutoff has been made. When the correct velocity change cutoff |v′−v|≥δ{sub min} is employed, the scattering angle can be integrated. A unified linearized Boltzmann collision operator for both inverse-square force law and rigid-sphere interactions is obtained. Like many other unified quantities such as transition moments, Fokker-Planck expansion coefficients and energy exchange rates obtained recently [Y. B. Chang and L. A. Viehland, AIP Adv. 1, 032128 (2011)], the difference between the two kinds of interactions is characterized by a parameter, γ, which is 1 for rigid-sphere interactions and −3 for inverse-square force law interactions. When the cutoff is removed by setting δ{sub min}=0, Hilbert's well known kernel for rigid-sphere interactions is recovered for γ = 1.
LINEAR COLLIDER PHYSICS RESOURCE BOOK FOR SNOWMASS 2001.
ABE,T.; DAWSON,S.; HEINEMEYER,S.; MARCIANO,W.; PAIGE,F.; TURCOT,A.S.; ET AL
2001-05-03
The American particle physics community can look forward to a well-conceived and vital program of experimentation for the next ten years, using both colliders and fixed target beams to study a wide variety of pressing questions. Beyond 2010, these programs will be reaching the end of their expected lives. The CERN LHC will provide an experimental program of the first importance. But beyond the LHC, the American community needs a coherent plan. The Snowmass 2001 Workshop and the deliberations of the HEPAP subpanel offer a rare opportunity to engage the full community in planning our future for the next decade or more. A major accelerator project requires a decade from the beginning of an engineering design to the receipt of the first data. So it is now time to decide whether to begin a new accelerator project that will operate in the years soon after 2010. We believe that the world high-energy physics community needs such a project. With the great promise of discovery in physics at the next energy scale, and with the opportunity for the uncovering of profound insights, we cannot allow our field to contract to a single experimental program at a single laboratory in the world. We believe that an e{sup +}e{sup {minus}} linear collider is an excellent choice for the next major project in high-energy physics. Applying experimental techniques very different from those used at hadron colliders, an e{sup +}e{sup {minus}} linear collider will allow us to build on the discoveries made at the Tevatron and the LHC, and to add a level of precision and clarity that will be necessary to understand the physics of the next energy scale. It is not necessary to anticipate specific results from the hadron collider programs to argue for constructing an e{sup +}e{sup {minus}} linear collider; in any scenario that is now discussed, physics will benefit from the new information that e{sup +}e{sup {minus}} experiments can provide.
IR OPTICS MEASUREMENT WITH LINEAR COUPLING'S ACTION-ANGLE PARAMETERIZATION.
LUO, Y.; BAI, M.; PILAT, R.; SATOGATA, T.; TRBOJEVIC, D.
2005-05-16
A parameterization of linear coupling in action-angle coordinates is convenient for analytical calculations and interpretation of turn-by-turn (TBT) beam position monitor (BPM) data. We demonstrate how to use this parameterization to extract the twiss and coupling parameters in interaction regions (IRs), using BPMs on each side of the long IR drift region. The example of TBT BPM analysis was acquired at the Relativistic Heavy Ion Collider (RHIC), using an AC dipole to excite a single eigenmode. Besides the full treatment, a fast estimate of beta*, the beta function at the interaction point (IP), is provided, along with the phase advance between these BPMs. We also calculate and measure the waist of the beta function and the local optics.
Extreme hydrogen plasma densities achieved in a linear plasma generator
Rooij, G. J. van; Veremiyenko, V. P.; Goedheer, W. J.; de Groot, B.; Kleyn, A. W.; Smeets, P. H. M.; Versloot, T. W.; Whyte, D. G.; Engeln, R.; Schram, D. C.; Cardozo, N. J. Lopes
2007-03-19
A magnetized hydrogen plasma beam was generated with a cascaded arc, expanding in a vacuum vessel at an axial magnetic field of up to 1.6 T. Its characteristics were measured at a distance of 4 cm from the nozzle: up to a 2 cm beam diameter, 7.5x10{sup 20} m{sup -3} electron density, {approx}2 eV electron and ion temperatures, and 3.5 km/s axial plasma velocity. This gives a 2.6x10{sup 24} H{sup +} m{sup -2} s{sup -1} peak ion flux density, which is unprecedented in linear plasma generators. The high efficiency of the source is obtained by the combined action of the magnetic field and an optimized nozzle geometry. This is interpreted as a cross-field return current that leads to power dissipation in the beam just outside the source.
Phase and Radial Motion in Ion Linear Accelerators
Energy Science and Technology Software Center (OSTI)
2007-03-29
Parmila is an ion-linac particle-dynamics code. The name comes from the phrase, "Phase and Radial Motion in Ion Linear Accelerators." The code generates DTL, CCDTL, and CCL accelerating cells and, using a "drift-kick" method, transforms the beam, represented by a collection of particles, through the linac. The code includes a 2-D and 3-D space-charge calculations. Parmila uses data generated by the Poisson Superfish postprocessor SEC. This version of Parmila was written by Harunori Takeda andmore » was supported through Feb. 2006 by James H. Billen. Setup installs executable programs Parmila.EXE, Lingraf.EXE, and ReadPMI.EXE in the LANL directory. The directory LANL\\Examples\\Parmila contains several subdirectories with sample files for Parmila.« less
Light-operated proximity detector with linear output
Simpson, M.L.; McNeilly, D.R.
1984-01-01
A light-operated proximity detector is described in which reflected light intensity from a surface whose proximity to the detector is to be gauged is translated directly into a signal proportional to the distance of the detector from the surface. A phototransistor is used to sense the reflected light and is connected in a detector circuit which maintains the phtotransistor in a saturated state. A negative feedback arrangement using an operational amplifier connected between the collector and emitter of the transistor provides an output at the output of the amplifier which is linearly proportional to the proximity of the surface to the detector containing the transistor. This direct proportional conversion is true even though the light intensity is varying with the proximity in proportion to the square of the inverse of the distance. The detector may be used for measuring the distance remotely from any target surface.
Light-operated proximity detector with linear output
Simpson, Marc L.; McNeilly, David R.
1985-01-01
A light-operated proximity detector is described in which reflected light intensity from a surface whose proximity to the detector is to be gauged is translated directly into a signal proportional to the distance of the detector from the surface. A phototransistor is used to sense the reflected light and is connected in a detector circuit which maintains the phototransistor in a saturated state. A negative feedback arrangement using an operational amplifier connected between the collector and emitter of the transistor provides an output at the output of the amplifier which is linearly proportional to the proximity of the surface to the detector containing the transistor. This direct proportional conversion is true even though the light intensity is varying with the proximity in proportion to the square of the inverse of the distance. The detector may be used for measuring the distance remotely from any target surface.
ANALYZING SURFACE ROUGHNESS DEPENDENCE OF LINEAR RF LOSSES
Reece, Charles E.; Kelley, Michael J.; Xu, Chen
2012-09-01
Topographic structure on Superconductivity Radio Frequency (SRF) surfaces can contribute additional cavity RF losses describable in terms of surface RF reflectivity and absorption indices of wave scattering theory. At isotropic homogeneous extent, Power Spectrum Density (PSD) of roughness is introduced and quantifies the random surface topographic structure. PSD obtained from different surface treatments of niobium, such Buffered Chemical Polishing (BCP), Electropolishing (EP), Nano-Mechanical Polishing (NMP) and Barrel Centrifugal Polishing (CBP) are compared. A perturbation model is utilized to calculate the additional rough surface RF losses based on PSD statistical analysis. This model will not consider that superconductor becomes normal conducting at fields higher than transition field. One can calculate the RF power dissipation ratio between rough surface and ideal smooth surface within this field range from linear loss mechanisms.
Detection of linear impermeable barriers by transient pressure analysis
Martinez-Romero, N.; Cinco-Ley, H.
1983-05-01
This work presents a new simple method to detect a linear impermeable barrier by analysis of transient pressure data. This technique is based on the desuperposition method (negative superposition) discussed by some authors and considers the calculation the pressure change caused by the presence of the barrier. The pressure change is analyzed to estimate the distance between the well and the barrier by using the type curve matching technique. Type curves are provided for both drawdown and build tests. The advantage of the technique presented in this work is that pressure data can be analyzed even if the second semilog straight line, whose slope is twice the slope of the first semilog straight line, is not reached. Examples of application are discussed for illustration.
Automated control of linear constricted plasma source array
Anders, Andre; Maschwitz, Peter A.
2000-01-01
An apparatus and method for controlling an array of constricted glow discharge chambers are disclosed. More particularly a linear array of constricted glow plasma sources whose polarity and geometry are set so that the contamination and energy of the ions discharged from the sources are minimized. The several sources can be mounted in parallel and in series to provide a sustained ultra low source of ions in a plasma with contamination below practical detection limits. The quality of film along deposition "tracks" opposite the plasma sources can be measured and compared to desired absolute or relative values by optical and/or electrical sensors. Plasma quality can then be adjusted by adjusting the power current values, gas feed pressure/flow, gas mixtures or a combination of some or all of these to improve the match between the measured values and the desired values.
RECENT PROGRESS TOWARD A MUON RECIRCULATING LINEAR ACCELERATOR
Slawomir Bogacz, Vasiliy Morozov, Yves Roblin, Kevin Beard
2012-07-01
Both Neutrino Factories (NF) and Muon Colliders (MC) require very rapid acceleration due to the short lifetime of muons. After a capture and bunching section, a linac raises the energy to about 900 MeV, and is followed by one or more Recirculating Linear Accelerators (RLA), possibly followed by a Rapid Cycling Synchnotron (RCS) or Fixed-Field Alternating Gradient (FFAG) ring. A RLA reuses the expensive RF linac section for a number of passes at the price of having to deal with different energies within the same linac. Various techniques including pulsed focusing quadruopoles, beta frequency beating, and multipass arcs have been investigated via simulations to improve the performance and reduce the cost of such RLAs.
Physics and technology of the next linear collider
1996-06-01
The authors present the prospects for the next generation of high-energy physics experiments with electron-positron colliding beams. This report summarizes the current status of the design and technological basis of a linear collider of center-of-mass energy 0.5--1.5 TeV, and the opportunities for high-energy physics experiments that this machine is expected to open. The physics goals discussed here are: Standard Model processes and simulation; top quark physics; Higgs boson searches and properties; supersymmetry; anomalous gauge boson couplings; strong WW scattering; new gauge bosons and exotic particles; e{sup {minus}}e{sup {minus}}, e{sup {minus}}{gamma}, and {gamma}{gamma} interactions; and precision tests of QCD.
Intersecting nonextreme p-branes and linear dilaton background
Chen, C.-M.; Gal'tsov, Dmitri V.; Ohta, Nobuyoshi
2005-08-15
We construct the general static solution to the supergravity action containing gravity, the dilaton and a set of antisymmetric forms describing the intersecting branes delocalized in the relative transverse dimensions. The solution is obtained by reducing the system to a set of separate Liouville equations (the intersection rules implying the separability); it contains the maximal number of free parameters corresponding to the rank of the differential equations. Imposing the requirement of the absence of naked singularities, we show that the general configurations are restricted to two and only two classes: the usual asymptotically flat intersecting branes, and the intersecting branes some of which are asymptotically flat and some approach the linear dilaton background at infinity. In both cases the configurations are black. These are supposed to be relevant for the description of the thermal phase of the QFT's in the corresponding Domain-Wall/QFT duality.
Non-linear radial spinwave modes in thin magnetic disks
Helsen, M. De Clercq, J.; Vansteenkiste, A.; Van Waeyenberge, B.; Weigand, M.
2015-01-19
We present an experimental investigation of radial spin-wave modes in magnetic nano-disks with a vortex ground state. The spin-wave amplitude was measured using a frequency-resolved magneto-optical spectrum analyzer, allowing for high-resolution resonance curves to be recorded. It was found that with increasing excitation amplitude up to about 10 mT, the lowest-order mode behaves strongly non-linearly as the mode frequency redshifts and the resonance peak strongly deforms. This behavior was quantitatively reproduced by micromagnetic simulations. Micromagnetic simulations showed that at higher excitation amplitudes, the spinwaves are transformed into a soliton by self-focusing, and collapse onto the vortex core, dispersing the energy in short-wavelength spinwaves. Additionally, this process can lead to switching of the vortex polarization through the injection of a Bloch point.
Beam dynamics in a long-pulse linear induction accelerator
Ekdahl, Carl; Abeyta, Epifanio O; Aragon, Paul; Archuleta, Rita; Cook, Gerald; Dalmas, Dale; Esquibel, Kevin; Gallegos, Robert A; Garnett, Robert; Harrison, James F; Johnson, Jeffrey B; Jacquez, Edward B; Mc Cuistian, Brian T; Montoya, Nicholas A; Nath, Subrato; Nielsen, Kurt; Oro, David; Prichard, Benjamin; Rose, Chris R; Sanchez, Manolito; Schauer, Martin M; Seitz, Gerald; Schulze, Martin; Bender, Howard A; Broste, William B; Carlson, Carl A; Frayer, Daniel K; Johnson, Douglas E; Tom, C Y; Trainham, C; Williams, John; Scarpetti, Raymond; Genoni, Thomas; Hughes, Thomas; Toma, Carsten
2010-01-01
The second axis of the Dual Axis Radiography of Hydrodynamic Testing (DARHT) facility produces up to four radiographs within an interval of 1.6 microseconds. It accomplishes this by slicing four micro-pulses out of a long 1.8-kA, 16.5-MeV electron beam pulse and focusing them onto a bremsstrahlung converter target. The long beam pulse is created by a dispenser cathode diode and accelerated by the unique DARHT Axis-II linear induction accelerator (LIA). Beam motion in the accelerator would be a problem for radiography. High frequency motion, such as from beam breakup instability, would blur the individual spots. Low frequency motion, such as produced by pulsed power variation, would produce spot to spot differences. In this article, we describe these sources of beam motion, and the measures we have taken to minimize it.
Cryogen free superconducting splittable quadrupole magnet for linear accelerators
Kashikhin, V.S.; Andreev, N.; Kerby, J.; Orlov, Y.; Solyak, N.; Tartaglia, M.; Velev, G.; /Fermilab
2011-09-01
A new superconducting quadrupole magnet for linear accelerators was fabricated at Fermilab. The magnet is designed to work inside a cryomodule in the space between SCRF cavities. SCRF cavities must be installed inside a very clean room adding issues to the magnet design, and fabrication. The designed magnet has a splittable along the vertical plane configuration and could be installed outside of the clean room around the beam pipe previously connected to neighboring cavities. For more convenient assembly and replacement a 'superferric' magnet configuration with four racetrack type coils was chosen. The magnet does not have a helium vessel and is conductively cooled from the cryomodule LHe supply pipe and a helium gas return pipe. The quadrupole generates 36 T integrated magnetic field gradient, has 600 mm effective length, and the peak gradient is 54 T/m. In this paper the quadrupole magnetic, mechanical, and thermal designs are presented, along with the magnet fabrication overview and first test results.
Linear nozzle with tailored gas plumes and method
Leon, David D.; Kozarek, Robert L.; Mansour, Adel; Chigier, Norman
1999-01-01
There is claimed a method for depositing fluid material from a linear nozzle in a substantially uniform manner across and along a surface. The method includes directing gaseous medium through said nozzle to provide a gaseous stream at the nozzle exit that entrains fluid material supplied to the nozzle, said gaseous stream being provided with a velocity profile across the nozzle width that compensates for the gaseous medium's tendency to assume an axisymmetric configuration after leaving the nozzle and before reaching the surface. There is also claimed a nozzle divided into respective side-by-side zones, or preferably chambers, through which a gaseous stream can be delivered in various velocity profiles across the width of said nozzle to compensate for the tendency of this gaseous medium to assume an axisymmetric configuration.
Linear particle accelerator with seal structure between electrodes and insulators
Broadhurst, John H.
1989-01-01
An electrostatic linear accelerator includes an electrode stack comprised of primary electrodes formed or Kovar and supported by annular glass insulators having the same thermal expansion rate as the electrodes. Each glass insulator is provided with a pair of fused-in Kovar ring inserts which are bonded to the electrodes. Each electrode is designed to define a concavo-convex particle trap so that secondary charged particles generated within the accelerated beam area cannot reach the inner surface of an insulator. Each insulator has a generated inner surface profile which is so configured that the electrical field at this surface contains no significant tangential component. A spark gap trigger assembly is provided, which energizes spark gaps protecting the electrodes affected by over voltage to prevent excessive energy dissipation in the electrode stack.
Acoustic methods to monitor sliver linear density and yarn strength
Sheen, Shuh-Haw; Chien, Hual-Te; Raptis, Apostolos C.
1997-01-01
Methods and apparatus are provided for monitoring sliver and yarn characteristics. Transverse waves are generated relative to the sliver or yarn. At least one acoustic sensor is in contact with the sliver or yarn for detecting waves coupled to the sliver or yarn and for generating a signal. The generated signal is processed to identify the predefined characteristics including sliver or yarn linear density. The transverse waves can be generated with a high-powered acoustic transmitter spaced relative to the sliver or yarn with large amplitude pulses having a central frequency in a range between 20 KHz and 40 KHz applied to the transmitter. The transverse waves can be generated by mechanically agitating the sliver or yarn with a tapping member.
Parallel computation of transverse wakes in linear colliders
Zhan, Xiaowei; Ko, Kwok
1996-11-01
SLAC has proposed the detuned structure (DS) as one possible design to control the emittance growth of long bunch trains due to transverse wakefields in the Next Linear Collider (NLC). The DS consists of 206 cells with tapering from cell to cell of the order of few microns to provide Gaussian detuning of the dipole modes. The decoherence of these modes leads to two orders of magnitude reduction in wakefield experienced by the trailing bunch. To model such a large heterogeneous structure realistically is impractical with finite-difference codes using structured grids. The authors have calculated the wakefield in the DS on a parallel computer with a finite-element code using an unstructured grid. The parallel implementation issues are presented along with simulation results that include contributions from higher dipole bands and wall dissipation.
Separated-orbit bisected energy-recovered linear accelerator
Douglas, David R.
2015-09-01
A separated-orbit bisected energy-recovered linear accelerator apparatus and method. The accelerator includes a first linac, a second linac, and a plurality of arcs of differing path lengths, including a plurality of up arcs, a plurality of downgoing arcs, and a full energy arc providing a path independent of the up arcs and downgoing arcs. The up arcs have a path length that is substantially a multiple of the RF wavelength and the full energy arc includes a path length that is substantially an odd half-integer multiple of the RF wavelength. Operation of the accelerator includes accelerating the beam utilizing the linacs and up arcs until the beam is at full energy, at full energy executing a full recirculation to the second linac using a path length that is substantially an odd half-integer of the RF wavelength, and then decelerating the beam using the linacs and downgoing arcs.
Microgrid Reliability Modeling and Battery Scheduling Using Stochastic Linear Programming
Cardoso, Goncalo; Stadler, Michael; Siddiqui, Afzal; Marnay, Chris; DeForest, Nicholas; Barbosa-Povoa, Ana; Ferrao, Paulo
2013-05-23
This paper describes the introduction of stochastic linear programming into Operations DER-CAM, a tool used to obtain optimal operating schedules for a given microgrid under local economic and environmental conditions. This application follows previous work on optimal scheduling of a lithium-iron-phosphate battery given the output uncertainty of a 1 MW molten carbonate fuel cell. Both are in the Santa Rita Jail microgrid, located in Dublin, California. This fuel cell has proven unreliable, partially justifying the consideration of storage options. Several stochastic DER-CAM runs are executed to compare different scenarios to values obtained by a deterministic approach. Results indicate that using a stochastic approach provides a conservative yet more lucrative battery schedule. Lower expected energy bills result, given fuel cell outages, in potential savings exceeding 6percent.
Method and apparatus for calibrating a linear variable differential transformer
Pokrywka, Robert J.
2005-01-18
A calibration apparatus for calibrating a linear variable differential transformer (LVDT) having an armature positioned in au LVDT armature orifice, and the armature able to move along an axis of movement. The calibration apparatus includes a heating mechanism with an internal chamber, a temperature measuring mechanism for measuring the temperature of the LVDT, a fixture mechanism with an internal chamber for at least partially accepting the LVDT and for securing the LVDT within the heating mechanism internal chamber, a moving mechanism for moving the armature, a position measurement mechanism for measuring the position of the armature, and an output voltage measurement mechanism. A method for calibrating an LVDT, including the steps of: powering the LVDT; heating the LVDT to a desired temperature; measuring the position of the armature with respect to the armature orifice; and measuring the output voltage of the LVDT.
Non-linear optical crystal vibration sensing device
Kalibjian, R.
1994-08-09
A non-linear optical crystal vibration sensing device including a photorefractive crystal and a laser is disclosed. The laser produces a coherent light beam which is split by a beam splitter into a first laser beam and a second laser beam. After passing through the crystal the first laser beam is counter-propagated back upon itself by a retro-mirror, creating a third laser beam. The laser beams are modulated, due to the mixing effect within the crystal by vibration of the crystal. In the third laser beam, modulation is stable and such modulation is converted by a photodetector into a usable electrical output, intensity modulated in accordance with vibration applied to the crystal. 3 figs.
Non-linear optical crystal vibration sensing device
Kalibjian, Ralph
1994-01-11
A non-linear optical crystal vibration sensing device (10) including a photorefractive crystal (26) and a laser (12). The laser (12 ) produces a coherent light beam (14) which is split by a beam splitter (18) into a first laser beam (20) and a second laser beam (22). After passing through the crystal (26) the first laser beam (20) is counter-propagated back upon itself by a retro-mirror (32), creating a third laser beam (30). The laser beams (20, 22, 30) are modulated, due to the mixing effect within the crystal (26) by vibration of the crystal (30). In the third laser beam (30), modulation is stable and such modulation is converted by a photodetector (34) into a usable electrical output, intensity modulated in accordance with vibration applied to the crystal (26).
Generalized space and linear momentum operators in quantum mechanics
Costa, Bruno G. da
2014-06-15
We propose a modification of a recently introduced generalized translation operator, by including a q-exponential factor, which implies in the definition of a Hermitian deformed linear momentum operator p{sup ^}{sub q}, and its canonically conjugate deformed position operator x{sup ^}{sub q}. A canonical transformation leads the Hamiltonian of a position-dependent mass particle to another Hamiltonian of a particle with constant mass in a conservative force field of a deformed phase space. The equation of motion for the classical phase space may be expressed in terms of the generalized dual q-derivative. A position-dependent mass confined in an infinite square potential well is shown as an instance. Uncertainty and correspondence principles are analyzed.
Linear Dichroism in Resonant Inelastic X-Ray Scattering to Molecular...
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Linear Dichroism in Resonant Inelastic X-Ray Scattering to Molecular Spin-Orbit States Linear Dichroism in Resonant Inelastic X-Ray Scattering to Molecular Spin-Orbit States Print...
A Beam Driven Plasma-Wakefield Linear Collider: From Higgs Factory...
Office of Scientific and Technical Information (OSTI)
A Beam Driven Plasma-Wakefield Linear Collider: From Higgs Factory to Multi-TeV Citation Details In-Document Search Title: A Beam Driven Plasma-Wakefield Linear Collider: From Higgs ...
Acceleration in the linear non-scaling fixed-field alternating...
Office of Scientific and Technical Information (OSTI)
Acceleration in the linear non-scaling fixed-field alternating-gradient accelerator EMMA Citation Details In-Document Search Title: Acceleration in the linear non-scaling ...
BenAbdallah, Abdallah; Hammami, Mohamed Ali; Kallel, Jalel
2009-03-05
In this paper we present some sufficient conditions for the robust stability and stabilization of time invariant uncertain piecewise linear system using homogenous piecewise polynomial Lyapunov function. The proposed conditions are given in terms of linear matrix inequalities which can be numerically solved. An application of the obtained result is given. It consists in resolving the stabilization of piecewise uncertain linear control systems by using a state piecewise linear feedback.
Comparative study of medium damped and detuned linear accelerator structures
Jean-Francois Ostiguy et al.
2001-08-22
Long range wakefields are a serious concern for a future linear collider based on room temperature accelerating structures. They can be suppressed either by detuning and or local damping or with some combination of both strategies. Detuning relies on precisely phasing the contributions of the dipole modes excited by the passage of a single bunch. This is accomplished by controlling individual mode frequencies, a process which dictates individual cell dimensional tolerances. Each mode must be excited with the correct strength; this in turn, determines cell-to-cell alignment tolerances. In contrast, in a locally damped structure, the modes are attenuated at the cell level. Clearly, mode frequencies and relative excitation become less critical in that context; mechanical fabrication tolerances can be relaxed. While local damping is ideal from the stand-point of long range wakefield suppression, this comes at the cost of reducing the shunt impedance and possibly unacceptable localized heating. Recently, the Medium Damped Structure (MDS), a compromise between detuning and local damping, has generated some interest. In this paper, we compare a hypothetical MDS to the NLC Rounded Damped Detuned Structure (RDDS) and investigate possible advantages from the standpoint fabrication tolerances and their relation to beam stability and emittance preservation.
Numerical simulation of linear fiction welding (LFW) processes
Fratini, L.; La Spisa, D. [University of Palermo-Dept. of Industrial engineering (Italy)
2011-05-04
Solid state welding processes are becoming increasingly important due to a large number of advantages related to joining ''unweldable'' materials and in particular light weight alloys. Linear friction welding (LFW) has been used successfully to bond non-axisymmetric components of a range of materials including titanium alloys, steels, aluminum alloys, nickel, copper, and also dissimilar material combinations. The technique is useful in the research of quality of the joints and in reducing costs of components and parts of the aeronautic and automotive industries.LFW involves parts to be welded through the relative reciprocating motion of two components under an axial force. In such process the heat source is given by the frictional forces work decaying into heat determining a local softening of the material and proper bonding conditions due to both the temperature increase and the local pressure of the two edges to be welded. This paper is a comparative test between the numerical model in two dimensions, i.e. in plane strain conditions, and in three dimensions of a LFW process of AISI1045 steel specimens. It must be observed that the 3D model assures a faithful simulation of the actual threedimensional material flow, even if the two-dimensional simulation computational times are very short, a few hours instead of several ones as the 3D model. The obtained results were compared with experimental values found out in the scientific literature.
Towards reversible basic linear algebra subprograms: A performance study
Perumalla, Kalyan S.; Yoginath, Srikanth B.
2014-12-06
Problems such as fault tolerance and scalable synchronization can be efficiently solved using reversibility of applications. Making applications reversible by relying on computation rather than on memory is ideal for large scale parallel computing, especially for the next generation of supercomputers in which memory is expensive in terms of latency, energy, and price. In this direction, a case study is presented here in reversing a computational core, namely, Basic Linear Algebra Subprograms, which is widely used in scientific applications. A new Reversible BLAS (RBLAS) library interface has been designed, and a prototype has been implemented with two modes: (1) a memory-mode in which reversibility is obtained by checkpointing to memory in forward and restoring from memory in reverse, and (2) a computational-mode in which nothing is saved in the forward, but restoration is done entirely via inverse computation in reverse. The article is focused on detailed performance benchmarking to evaluate the runtime dynamics and performance effects, comparing reversible computation with checkpointing on both traditional CPU platforms and recent GPU accelerator platforms. For BLAS Level-1 subprograms, data indicates over an order of magnitude better speed of reversible computation compared to checkpointing. For BLAS Level-2 and Level-3, a more complex tradeoff is observed between reversible computation and checkpointing, depending on computational and memory complexities of the subprograms.
Towards reversible basic linear algebra subprograms: A performance study
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Perumalla, Kalyan S.; Yoginath, Srikanth B.
2014-12-06
Problems such as fault tolerance and scalable synchronization can be efficiently solved using reversibility of applications. Making applications reversible by relying on computation rather than on memory is ideal for large scale parallel computing, especially for the next generation of supercomputers in which memory is expensive in terms of latency, energy, and price. In this direction, a case study is presented here in reversing a computational core, namely, Basic Linear Algebra Subprograms, which is widely used in scientific applications. A new Reversible BLAS (RBLAS) library interface has been designed, and a prototype has been implemented with two modes: (1) amore » memory-mode in which reversibility is obtained by checkpointing to memory in forward and restoring from memory in reverse, and (2) a computational-mode in which nothing is saved in the forward, but restoration is done entirely via inverse computation in reverse. The article is focused on detailed performance benchmarking to evaluate the runtime dynamics and performance effects, comparing reversible computation with checkpointing on both traditional CPU platforms and recent GPU accelerator platforms. For BLAS Level-1 subprograms, data indicates over an order of magnitude better speed of reversible computation compared to checkpointing. For BLAS Level-2 and Level-3, a more complex tradeoff is observed between reversible computation and checkpointing, depending on computational and memory complexities of the subprograms.« less
Environmental Survey preliminary report, Stanford Linear Accelerator Center, Stanford, California
Not Available
1988-07-01
This report presents the preliminary findings from the first phase of the Survey of the US Department of Energy (DOE) Stanford Linear Accelerator Center (SLAC) at Stanford, California, conducted February 29 through March 4, 1988. The Survey is being conducted by an interdisciplinary team of environmental specialists, led and managed by the Office of Environment, Safety and Health's Office of Environmental Audit. Individual team components are being supplied by a private contractor. The objective of the Survey is to identify environmental problems and areas of environmental risk associated with the SLAC. The Survey covers all environmental media and all areas of environmental regulation and is being performed in accordance with the DOE Environmental Survey Manual. This phase of the Survey involves the review of existing site environmental data, observations of the operations at the SLAC, and interviews with site personnel. The Survey team is developing a Sampling and Analysis Plan to assist in further assessing certain of the environmental problems identified during its on-site activities. The Sampling and Analysis Plan will be executed by a DOE National Laboratory or a support contractor. When completed, the results will be incorporated into the Environmental Survey Interim Report for the SLAC facility. The Interim Report will reflect the final determinations of the SLAC Survey. 95 refs., 25 figs., 25 tabs.
LIGA-fabricated compact mm-wave linear accelerator cavities.
Song, J.J.; Bajikar, S.S.; DeCarlo, F.; Kang, Y.W.; Kustom, R.L.; Mancini, D.C.; Nassiri, A.; Lai, B.; Feinerman, A.D.; White, V.
1998-03-23
Millimeter-wave rf cavities for use in linear accelerators, free-electron lasers, and mm-wave undulatory are under development at Argonne National Laboratory. Typical cavity dimensions are in the 1000 mm range, and the overall length of the accelerator structure, which consists of 30-100 cavities, is about 50-100 mm. An accuracy of 0.2% in the cavity dimensions is necessary in order to achieve a high Q-factor of the cavity. To achieve this these structures are being fabricated using deep X-ray lithography, electroforming, and assembly (LIGA). The first prototype cavity structures are designed for 108 GHz and 2p/3-mode operation. Input and output couplers are integrated with the cavity structures. The cavities are fabricated on copper substrates by electroforming copper into 1-mm-thick PMMA resists patterned by deep x-ray lithography and polishing the copper down to the desired thickness. These are fabricated separately and subsequently assembled with precision spacing and alignment using microspheres, optical fibers, or microfabricated spacers/alignment pieces. Details of the fabrication process, alignment, and assembly work are presented in here.
The LLNL Flash X-Ray Induction Linear Accelerator (FXR)
Multhauf, L G
2002-09-19
The FXR is an induction linear accelerator used for high-speed radiography at the Lawrence Livermore National Laboratory's Experimental Test Site. It was designed specifically for the radiography of very thick explosive objects. Since its completion in 1982, it has been very actively used for a large variety of explosives tests, and has been periodically upgraded to achieve higher performance. Upgrades have addressed machine reliability, radiographic sensitivity and resolution, two-frame imaging by double pulsing improvements that are described in detail in the paper. At the same time, the facility in which it was installed has also been extensively upgraded, first by adding space for optical and interferometric diagnostics, and more recently by adding a containment chamber to prevent the environmental dispersal of hazardous and radioactive materials. The containment addition also further expands space for new non-radiographic diagnostics. The new Contained Firing Facility is still in the process of activation. At the same time, FXR is continuing to undergo modifications aimed primarily at further increasing radiographic resolution and sensitivity, and at improving double-pulsed performance.
Systematic study of doping dependence on linear magnetoresistance in p-PbTe
Schneider, J. M.; Chitta, V. A.; Oliveira, N. F.; Peres, M. L. Castro, S. de; Soares, D. A. W.; Wiedmann, S.; Zeitler, U.; Abramof, E.; Rappl, P. H. O.; Mengui, U. A.
2014-10-20
We report on a large linear magnetoresistance effect observed in doped p-PbTe films. While undoped p-PbTe reveals a sublinear magnetoresistance, p-PbTe films doped with BaF{sub 2} exhibit a transition to a nearly perfect linear magnetoresistance behaviour that is persistent up to 30?T. The linear magnetoresistance slope ?R/?B is to a good approximation, independent of temperature. This is in agreement with the theory of Quantum Linear Magnetoresistance. We also performed magnetoresistance simulations using a classical model of linear magnetoresistance. We found that this model fails to explain the experimental data. A systematic study of the doping dependence reveals that the linear magnetoresistance response has a maximum for small BaF{sub 2} doping levels and diminishes rapidly for increasing doping levels. Exploiting the huge impact of doping on the linear magnetoresistance signal could lead to new classes of devices with giant magnetoresistance behavior.
Liu, Jian; Guo, Pan; University of Chinese Academy of Sciences, Beijing 100049 ; Wang, Chunlei; Shi, Guosheng Fang, Haiping
2013-12-21
Using molecular dynamics simulations, we show a fine linear relationship between surface energies and microscopic Lennard-Jones parameters of super-hydrophilic surfaces. The linear slope of the super-hydrophilic surfaces is consistent with the linear slope of the super-hydrophobic, hydrophobic, and hydrophilic surfaces where stable water droplets can stand, indicating that there is a universal linear behavior of the surface energies with the water-surface van der Waals interaction that extends from the super-hydrophobic to super-hydrophilic surfaces. Moreover, we find that the linear relationship exists for various substrate types, and the linear slopes of these different types of substrates are dependent on the surface atom density, i.e., higher surface atom densities correspond to larger linear slopes. These results enrich our understanding of water behavior on solid surfaces, especially the water wetting behaviors on uncharged super-hydrophilic metal surfaces.
An implementation analysis of the linear discontinuous finite element method
Becker, T. L.
2013-07-01
This paper provides an implementation analysis of the linear discontinuous finite element method (LD-FEM) that spans the space of (l, x, y, z). A practical implementation of LD includes 1) selecting a computationally efficient algorithm to solve the 4 x 4 matrix system Ax = b that describes the angular flux in a mesh element, and 2) choosing how to store the data used to construct the matrix A and the vector b to either reduce memory consumption or increase computational speed. To analyze the first of these, three algorithms were selected to solve the 4 x 4 matrix equation: Cramer's rule, a streamlined implementation of Gaussian elimination, and LAPACK's Gaussian elimination subroutine dgesv. The results indicate that Cramer's rule and the streamlined Gaussian elimination algorithm perform nearly equivalently and outperform LAPACK's implementation of Gaussian elimination by a factor of 2. To analyze the second implementation detail, three formulations of the discretized LD-FEM equations were provided for implementation in a transport solver: 1) a low-memory formulation, which relies heavily on 'on-the-fly' calculations and less on the storage of pre-computed data, 2) a high-memory formulation, which pre-computes much of the data used to construct A and b, and 3) a reduced-memory formulation, which lies between the low - and high-memory formulations. These three formulations were assessed in the Jaguar transport solver based on relative memory footprint and computational speed for increasing mesh size and quadrature order. The results indicated that the memory savings of the low-memory formulation were not sufficient to warrant its implementation. The high-memory formulation resulted in a significant speed advantage over the reduced-memory option (10-50%), but also resulted in a proportional increase in memory consumption (5-45%) for increasing quadrature order and mesh count; therefore, the practitioner should weigh the system memory constraints against any
Performance Models for the Spike Banded Linear System Solver
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Manguoglu, Murat; Saied, Faisal; Sameh, Ahmed; Grama, Ananth
2011-01-01
With availability of large-scale parallel platforms comprised of tens-of-thousands of processors and beyond, there is significant impetus for the development of scalable parallel sparse linear system solvers and preconditioners. An integral part of this design process is the development of performance models capable of predicting performance and providing accurate cost models for the solvers and preconditioners. There has been some work in the past on characterizing performance of the iterative solvers themselves. In this paper, we investigate the problem of characterizing performance and scalability of banded preconditioners. Recent work has demonstrated the superior convergence properties and robustness of banded preconditioners,more » compared to state-of-the-art ILU family of preconditioners as well as algebraic multigrid preconditioners. Furthermore, when used in conjunction with efficient banded solvers, banded preconditioners are capable of significantly faster time-to-solution. Our banded solver, the Truncated Spike algorithm is specifically designed for parallel performance and tolerance to deep memory hierarchies. Its regular structure is also highly amenable to accurate performance characterization. Using these characteristics, we derive the following results in this paper: (i) we develop parallel formulations of the Truncated Spike solver, (ii) we develop a highly accurate pseudo-analytical parallel performance model for our solver, (iii) we show excellent predication capabilities of our model – based on which we argue the high scalability of our solver. Our pseudo-analytical performance model is based on analytical performance characterization of each phase of our solver. These analytical models are then parameterized using actual runtime information on target platforms. An important consequence of our performance models is that they reveal underlying performance bottlenecks in both serial and parallel formulations. All of our results are validated
Linearization of scan velocity of resonant vibrating-mirror beam deflectors
Yeung, E.S.; Chen, S.L.
1991-01-15
A means and method for producing linearization of scan velocity of resonant vibrating-mirror beam deflectors in laser scanning system including presenting an elliptical convex surface to the scanning beam to reflect the scanning beam to the focal plane of the scanning line. The elliptical surface is shaped to produce linear velocity of the reflective scanning beam at the focal plane. Maximization of linearization is accomplished by considering sets of criteria for different scanning applications. 6 figures.
Energy level alignment of self-assembled linear chains of benzenediami...
Office of Scientific and Technical Information (OSTI)
Energy level alignment of self-assembled linear chains of benzenediamine on Au(111) from ... This content will become publicly available on March 24, 2017 Title: Energy level ...
Non-Linear Luminescent Coupling in Series-Connected Multijunction Solar Cells
Steiner, M. A.; Geisz, J. F.
2012-06-18
The assumption of superposition or linearity of photocurrent with solar flux is widespread for calculations and measurements of solar cells. The well-known effect of luminescent coupling in multijunction solar cells has also been assumed to be linear with excess current. Here we show significant non-linearities in luminescent coupling in III-V multijunction solar cells and propose a simple model based on competition between radiative and nonradiative processes in the luminescent junction to explain these non-linearities. We demonstrate a technique for accurately measuring the junction photocurrents under a specified reference spectrum, that accounts for and quantifies luminescent coupling effects.
LED Linear Lamps and Troffer Lighting: CALiPER Report Series 21
Beeson, Tracy; Miller, Naomi
2014-06-17
Video about CALiPER Report Series 21 on LED Linear Lamps and Troffer Lighting, featuring interviews with Tracy Beeson and Naomi Miller of Pacific Northwest National Laboratory.
Project Profile: Commercial Development of an Advanced Linear-Fresnel-Based
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
CSP Concept | Department of Energy Commercial Development of an Advanced Linear-Fresnel-Based CSP Concept Project Profile: Commercial Development of an Advanced Linear-Fresnel-Based CSP Concept SkyFuel logo SkyFuel, under the CSP R&D FOA, is developing a commercial linear-Fresnel-based advanced CSP system called Linear Power Tower (LPT). The company aims to make significant improvements in the cost and viability of utility-scale dispatchable solar power. Approach Image of Skyfuel
Text-Alternative Version: CALiPER Series 21 on LED Linear Lamps and Troffer Lighting
Broader source: Energy.gov [DOE]
Following is a text version of a video about CALiPER Application Report Series 21 on LED Linear Lamps and Troffer Lighting.
2011 Annual Planning Summary for Stanford Linear Accelerator Center Site Office (SLAC)
Broader source: Energy.gov [DOE]
The ongoing and projected Environmental Assessments and Environmental Impact Statements for 2011 and 2012 within the Stanford Linear Accelerator Center Site Office (SLAC SO) (See also Science).
LED Linear Lamps and Troffer Lighting: CALiPER Report Series 21
Beeson, Tracy; Miller, Naomi
2014-06-23
Video about CALiPER Report Series 21 on LED Linear Lamps and Troffer Lighting, featuring interviews with Tracy Beeson and Naomi Miller of Pacific Northwest National Laboratory.
Tuning the DARHT Axis-II linear induction accelerator focusing
Ekdahl, Carl A.
2012-04-24
Flash radiography of large hydrodynamic experiments driven by high explosives is a well-known diagnostic technique in use at many laboratories, and the Dual-Axis Radiography for Hydrodynamic Testing (DARHT) facility at Los Alamos produces flash radiographs of large hydrodynamic experiments. Two linear induction accelerators (LIAs) make the bremsstrahlung radiographic source spots for orthogonal views of each test. The 2-kA, 20-MeV Axis-I LIA creates a single 60-ns radiography pulse. The 1.7-kA, 16.5-MeV Axis-II LIA creates up to four radiography pulses by kicking them out of a longer pulse that has a 1.6-{mu}s flattop. The Axis-II injector, LIA, kicker, and downstream transport (DST) to the bremsstrahlung converter are described. Adjusting the magnetic focusing and steering elements to optimize the electron-beam transport through an LIA is often called 'tuning.' As in all high-current LIAs, the focusing field is designed to be as close to that of the ideal continuous solenoid as physically possible. In ideal continuous solenoidal transport a smoothly varying beam size can easily be found for which radial forces balance, and the beam is said to be 'matched' to the focusing field. A 'mismatched' beam exhibits unwanted oscillations in size, which are a source of free energy that contributes to emittance growth. This is undesirable, because in the absence of beam-target effects, the radiographic spot size is proportional to the emittance. Tuning the Axis-II LIA is done in two steps. First, the solenoidal focusing elements are set to values designed to provide a matched beam with little or no envelope oscillations, and little or no beam-breakup (BBU) instability growth. Then, steering elements are adjusted to minimize the motion of the centroid of a well-centered beam at the LIA exit. This article only describes the design of the tune for the focusing solenoids. The DARHT Axis-II LIA was required to be re-tuned after installing an accelerator cell to replace a failed
Proceedings of the Oak Ridge Electron Linear Accelerator (ORELA) Workshop
Dunn, M.E.
2006-02-27
The Oak Ridge National Laboratory (ORNL) organized a workshop at ORNL July 14-15, 2005, to highlight the unique measurement capabilities of the Oak Ridge Electron Linear Accelerator (ORELA) facility and to emphasize the important role of ORELA for performing differential cross-section measurements in the low-energy resonance region that is important for nuclear applications such as nuclear criticality safety, nuclear reactor and fuel cycle analysis, stockpile stewardship, weapons research, medical diagnosis, and nuclear astrophysics. The ORELA workshop (hereafter referred to as the Workshop) provided the opportunity to exchange ideas and information pertaining to nuclear cross-section measurements and their importance for nuclear applications from a variety of perspectives throughout the U.S. Department of Energy (DOE). Approximately 50 people, representing DOE, universities, and seven U.S. national laboratories, attended the Workshop. The objective of the Workshop was to emphasize the technical community endorsement for ORELA in meeting nuclear data challenges in the years to come. The Workshop further emphasized the need for a better understanding of the gaps in basic differential nuclear measurements and identified the efforts needed to return ORELA to a reliable functional measurement facility. To accomplish the Workshop objective, nuclear data experts from national laboratories and universities were invited to provide talks emphasizing the unique and vital role of the ORELA facility for addressing nuclear data needs. ORELA is operated on a full cost-recovery basis with no single sponsor providing complete base funding for the facility. Consequently, different programmatic sponsors benefit by receiving accurate cross-section data measurements at a reduced cost to their respective programs; however, leveraging support for a complex facility such as ORELA has a distinct disadvantage in that the programmatic funds are only used to support program
A dosimetric characterization of a novel linear accelerator collimator
Thompson, C. M.; Weston, S. J. Cosgrove, V. C.; Thwaites, D. I.
2014-03-15
Purpose: The aim of this work is to characterize a new linear accelerator collimator which contains a single pair of sculpted diaphragms mounted orthogonally to a 160 leaf multileaf collimator (MLC). The diaphragms have “thick” regions providing full attenuation and “thin” regions where attenuation is provided by both the leaves and the diaphragm. The leaves are mounted on a dynamic leaf guide allowing rapid leaf motion and leaf travel over 350 mm. Methods: Dosimetric characterization, including assessment of leaf transmission, leaf tip transmission, penumbral width, was performed in a plotting tank. Head scatter factor was measured using a mini-phantom and the effect of leaf guide position on output was assessed using a water phantom. The tongue and groove effect was assessed using multiple exposures on radiochromic film. Leaf reproducibility was assessed from portal images of multiple abutting fields. Results: The maximum transmission through the multileaf collimator is 0.44% at 6 MV and 0.52% at 10 MV. This reduced to 0.22% and 0.27%, respectively, when the beam passes through the dynamic leaf guide in addition to the MLC. The maximum transmission through the thick part of the diaphragm is 0.32% and 0.36% at 6 and 10 MV. The combination of leaf and diaphragm transmission ranges from 0.08% to 0.010% at 6 MV and 0.10% to 0.14% depending on whether the shielding is through the thick or thin part of the diaphragm. The off-axis intertip transmission for a zero leaf gap is 2.2% at 6 and 10 MV. The leaf tip penumbra for a 100 × 100 mm field ranges from 5.4 to 4.3 mm at 6 and 10 MV across the full range of leaf motion when measured in the AB direction, which reduces to 4.0–3.4 mm at 6 MV and 4.5–3.8 mm at 10 MV when measured in the GT direction. For a 50 × 50 mm field, the diaphragm penumbra ranges from 4.3 to 3.7 mm at 6 MV and 4.5 to 4.1 mm at 10 MV in the AB direction and 3.7 to 3.2 mm at 6 MV and 4.2 to 3.7 mm when measured in the GT direction. The
System and method for linearly amplifying optical analog signals by backward Raman scattering
Lin, Cheng-Heui
1988-01-01
A system for linearly amplifying an optical analog signal by backward stimulated Raman scattering comprises a laser source for generating a pump pulse; and an optic fiber having two opposed apertures, a first aperture for receiving the pump pulse and a second aperture for receiving the optical analog signal, wherein the optical analog signal is linearly amplified to an amplified optical analog signal.
System and method for linearly amplifying optical analog signals by backward Raman scattering
Lin, Cheng-Heui
1988-07-05
A system for linearly amplifying an optical analog signal by backward stimulated Raman scattering comprises a laser source for generating a pump pulse; and an optic fiber having two opposed apertures, a first aperture for receiving the pump pulse and a second aperture for receiving the optical analog signal, wherein the optical analog signal is linearly amplified to an amplified optical analog signal.
DOE Publishes CALiPER Report on Linear (T8) LED Lamps in Recessed Troffers
Broader source: Energy.gov [DOE]
The U.S. Department of Energy's CALiPER program has released Report 21.2, which is part of a series of investigations on linear LED lamps. Report 21.2 focuses on the performance of three linear (T8...
Sixth SIAM conference on applied linear algebra: Final program and abstracts. Final technical report
1997-12-31
Linear algebra plays a central role in mathematics and applications. The analysis and solution of problems from an amazingly wide variety of disciplines depend on the theory and computational techniques of linear algebra. In turn, the diversity of disciplines depending on linear algebra also serves to focus and shape its development. Some problems have special properties (numerical, structural) that can be exploited. Some are simply so large that conventional approaches are impractical. New computer architectures motivate new algorithms, and fresh ways to look at old ones. The pervasive nature of linear algebra in analyzing and solving problems means that people from a wide spectrum--universities, industrial and government laboratories, financial institutions, and many others--share an interest in current developments in linear algebra. This conference aims to bring them together for their mutual benefit. Abstracts of papers presented are included.
Results and Comparison from the SAM Linear Fresnel Technology Performance Model: Preprint
Wagner, M. J.
2012-04-01
This paper presents the new Linear Fresnel technology performance model in NREL's System Advisor Model. The model predicts the financial and technical performance of direct-steam-generation Linear Fresnel power plants, and can be used to analyze a range of system configurations. This paper presents a brief discussion of the model formulation and motivation, and provides extensive discussion of the model performance and financial results. The Linear Fresnel technology is also compared to other concentrating solar power technologies in both qualitative and quantitative measures. The Linear Fresnel model - developed in conjunction with the Electric Power Research Institute - provides users with the ability to model a variety of solar field layouts, fossil backup configurations, thermal receiver designs, and steam generation conditions. This flexibility aims to encompass current market solutions for the DSG Linear Fresnel technology, which is seeing increasing exposure in fossil plant augmentation and stand-alone power generation applications.
Feng, G.; Deriy, B.; Wang, J.; Accelerator Systems Division
2008-01-01
The APS booster ring uses ramping power supplies to power the sextupole, quadrupole, and dipole magnets as the beam energy ramps up linearly to 7 GeV. Due to the circuit topology used, those supplies are unable to follow the linear ramp to the desired accuracy. The best regulation achieved is 0.25% while 0.1% is desired. In addition to the unsatisfying regulation, those supplies are sensitive to AC line perturbation and are not able to reject AC line noises of more than a few tens of hertz. To improve the performance, a linear MOSFET regulation system using paralleled MOSFET devices in series with the power supply is proposed. The system uses a realtime current feedback loop to force the MOSFETs to work in the linear operation mode. By using this linear MOSFET regulator, the voltage drop on MOSFETs, and hence the voltage imposed on magnets, can be regulated very quickly. As a result, the regulation of the magnet current can be improved significantly. So far the simulation results show that with the linear regulator, the current regulation can be improved to better than 0.1%. Because of the high bandwidth of the linear regulator, it can reduce the harmonic content in the output current as well as reject the AC line disturbance. This paper discusses the circuit topology, the regulation method, and the simulation results.
Efficient Algorithms for Estimating the Absorption Spectrum within Linear Response TDDFT
Brabec, Jiri; Lin, Lin; Shao, Meiyue; Govind, Niranjan; Yang, Chao; Saad, Yousef; Ng, Esmond
2015-10-06
We present two iterative algorithms for approximating the absorption spectrum of molecules within linear response of time-dependent density functional theory (TDDFT) framework. These methods do not attempt to compute eigenvalues or eigenvectors of the linear response matrix. They are designed to approximate the absorption spectrum as a function directly. They take advantage of the special structure of the linear response matrix. Neither method requires the linear response matrix to be constructed explicitly. They only require a procedure that performs the multiplication of the linear response matrix with a vector. These methods can also be easily modified to efficiently estimate the density of states (DOS) of the linear response matrix without computing the eigenvalues of this matrix. We show by computational experiments that the methods proposed in this paper can be much more efficient than methods that are based on the exact diagonalization of the linear response matrix. We show that they can also be more efficient than real-time TDDFT simulations. We compare the pros and cons of these methods in terms of their accuracy as well as their computational and storage cost.
Linear Dichroism in Resonant Inelastic X-Ray Scattering to Molecular
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Spin-Orbit States Linear Dichroism in Resonant Inelastic X-Ray Scattering to Molecular Spin-Orbit States Linear Dichroism in Resonant Inelastic X-Ray Scattering to Molecular Spin-Orbit States Print Thursday, 17 December 2009 13:47 Schematic representation of linear dichroism observed in KL x-ray emission. Coupling between the spin-orbit interaction and the molecular field, oriented along the chemical bond, leads to different spin-orbit ratios as a function of the angle between the incoming
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... Fig. 3 shows the SEM micrographs of the zone plates' outer regions. The zone plates are 30 ... Figure 3. SEM micrographs of 12 nm (left) and 10 nm (right) zone plates, fabricated using ...
Bhattacharjee, Saurav Das, Nilakshi
2015-10-15
A systematic theoretical investigation has been carried out on the role of dust charging dynamics on the nature and stability of DIA (Dust Ion Acoustic) mode in complex plasma. The study has been made for both linear and non-linear scale regime of DIA mode. The observed results have been characterized in terms of background plasma responses towards dust surface responsible for dust charge fluctuation, invoking important dusty plasma parameters, especially the ion flow speed and dust size. The linear analyses confirm the nature of instability in DIA mode in presence of dust charge fluctuation. The instability shows a damping of DIA mode in subsonic flow regime followed by a gradual growth in instability in supersonic limit of ion flow. The strength of non-linearity and their existence domain is found to be driven by different dusty plasma parameters. As dust is ubiquitous in interstellar medium with plasma background, the study also addresses the possible effect of dust charging dynamics in gravito-electrostatic characterization and the stability of dust molecular clouds especially in proto-planetary disc. The observations are influential and interesting towards the understanding of dust settling mechanism and formation of dust environments in different regions in space.
The Effective Combination of Mesh Adaptation and Non-linearThermo...
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The Effective Combination of Mesh Adaptation and Non-linear Thermo-mechanical Solution Components for the Modeling of Weld Failures. Citation Details In-Document Search Title: The...
A Beam Driven Plasma-Wakefield Linear Collider: From Higgs Factory...
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A Beam Driven Plasma-Wakefield Linear Collider: From Higgs Factory to Multi-TeV Summarized for CSS2013 E. Adli, J.P.Delahaye, S.J.Gessner, M.J. Hogan, T. Raubenheimer (SLAC) W.An,...
LED Linear Lamps and Troffer Lighting: CALiPER Report Series 21
Broader source: Energy.gov [DOE]
View the video about CALiPER Report Series 21 on LED Linear Lamps and Troffer Lighting, featuring interviews with Tracy Beeson and Naomi Miller of Pacific Northwest National Laboratory.
13th International Conference on Magnetically Levitated Systems and Linear Drives
Not Available
1993-09-01
This report contains short papers on research being conducted throughout the world on magnetically levitated systems, mainly consisting of trains, and magnetic linear drives. These papers have been index separately elsewhere on the data base.
DYNAMICAL STABILITY AND QUANTUM CHAOS OF IONS IN A LINEAR TRAP (1999002ER).
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(Technical Report) | SciTech Connect Technical Report: DYNAMICAL STABILITY AND QUANTUM CHAOS OF IONS IN A LINEAR TRAP (1999002ER). Citation Details In-Document Search Title: DYNAMICAL STABILITY AND QUANTUM CHAOS OF IONS IN A LINEAR TRAP (1999002ER). The realization of a paradigm chaotic system, namely the harmonically driven oscillator, in the quantum domain using cold trapped ions driven by lasers is theoretically investigated. The simplest characteristics of regular and chaotic dynamics
Vibration Stabilization of a Mechanical Model of a X-Band Linear Collider Final Focus Magnet
Frisch, Josef; Chang, Allison; Decker, Valentin; Doyle, Eric; Eriksson, Leif; Hendrickson, Linda; Himel, Thomas; Markiewicz, Thomas; Partridge, Richard; Seryi, Andrei; /SLAC
2006-09-28
The small beam sizes at the interaction point of a X-band linear collider require mechanical stabilization of the final focus magnets at the nanometer level. While passive systems provide adequate performance at many potential sites, active mechanical stabilization is useful if the natural or cultural ground vibration is higher than expected. A mechanical model of a room temperature linear collider final focus magnet has been constructed and actively stabilized with an accelerometer based system.
Of Linear Colliders, the GDE Workshop at Bangalore, Mughals, Camels, Elephants and Sundials
Loew, Greg
2006-04-17
In this colloquium, the speaker will give a summary of the recent International Linear Collider (ILC) Global Design Effort (GDE) Workshop at Bangalore and how the High Energy Physics community converged to this meeting after many years of electron-positron linear collider design and experimental work. Given that this workshop for the first time took place in India, the speaker will also show a few pictures and talk briefly about what he learned in that fascinating country.
Probing the Linear Polarization of Gluons in Unpolarized Hadrons at EIC
Boer, Daniel; Brodsky, Stanley J.; Mulders, Piet J.; Pisano, Cristian; /Cagliari U. /INFN, Cagliari
2011-08-17
Gluons inside unpolarized hadrons can be linearly polarized provided they have a nonzero transverse momentum. The simplest and theoretically safest way to probe this TMD distribution of linearly polarized gluons is through cos 2{phi} asymmetries in heavy quark pair or dijet production in electron-hadron collisions. Future EIC or LHeC experiments are ideally suited for this purpose. Here we estimate the maximum asymmetries for EIC kinematics.
DOE - Office of Legacy Management -- Yale Heavy Ion Linear Accelerator - CT
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05 Yale Heavy Ion Linear Accelerator - CT 05 FUSRAP Considered Sites Site: Yale Heavy Ion Linear Accelerator (CT.05) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: New Haven , Connecticut CT.05-1 Evaluation Year: 1987 CT.05-3 Site Operations: Research and development with solvents. CT.05-1 Site Disposition: Eliminated - Potential for contamination remote based on limited amount of materials handled CT.05-3 Radioactive Materials
Simple Limits on Achieving A Quasi-Linear Magnetic Compression for an FEL Driver
Sun, Yipeng; /SLAC
2012-02-16
Free electron lasers (FEL) need a very bright electron beam in three dimensions and a high peak charge density. In order to compress an initially longer electron bunch generated from the photoinjector, magnetic bunch compression systems are widely employed. In this paper, first harmonic RF linearization and its associated requirements are reviewed. Meanwhile it is also briefly discussed what is the relation between a proper initial bunch length and main RF frequency, when a harmonic RF linearization is included. Then given a reasonable bunch compression ratio, a proper initial bunch length as a function of the main RF frequency and RF phase is estimated analytically by several approaches, assuming that no harmonic RF section is needed to linearize the energy modulation introduced during main RF acceleration, and at the same time still linearly compress the bunch length. Next the upper limit of the bunch compression ratio in a single stage is evaluated analytically. The analytical relations derived on choosing a proper initial bunch length as a function of main RF frequency are confirmed by numerical simulation. These simple limit provide rough estimations and may be beneficial for choosing bunch compression ratios in different stages of an FEL driver, especially in a first stage bunch compression where there is usually a harmonic RF linearization applied. It may also be useful in evaluating the possibility of low charge operation mode without any harmonic RF linearization, where a shorter initial bunch length can be achieved from the photoinjector.
Amesos2 and Belos: Direct and Iterative Solvers for Large Sparse Linear Systems
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Bavier, Eric; Hoemmen, Mark; Rajamanickam, Sivasankaran; Thornquist, Heidi
2012-01-01
Solvers for large sparse linear systems come in two categories: direct and iterative. Amesos2, a package in the Trilinos software project, provides direct methods, and Belos, another Trilinos package, provides iterative methods. Amesos2 offers a common interface to many different sparse matrix factorization codes, and can handle any implementation of sparse matrices and vectors, via an easy-to-extend C++ traits interface. It can also factor matrices whose entries have arbitrary “Scalar” type, enabling extended-precision and mixed-precision algorithms. Belos includes many different iterative methods for solving large sparse linear systems and least-squares problems. Unlike competing iterative solver libraries, Belos completely decouples themore » algorithms from the implementations of the underlying linear algebra objects. This lets Belos exploit the latest hardware without changes to the code. Belos favors algorithms that solve higher-level problems, such as multiple simultaneous linear systems and sequences of related linear systems, faster than standard algorithms. The package also supports extended-precision and mixed-precision algorithms. Together, Amesos2 and Belos form a complete suite of sparse linear solvers.« less
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
current zone plates but will improve with new zone plates Detectors Hemispherical electron energy analyzer; total electron yield detector Spot size at sample 300-500 nm with...
Ruth, R.D.
1991-07-01
This report discusses the following topics: SLC performance and fundamental limits; obtaining the energy in an NLC; obtaining the luminosity in an NLC; and example designs and future potential.
Viljoen, Nolan; Schuknecht, Nathan
2012-05-28
Included herein is SkyFuel’s detailed assessment of the potential for a direct molten salt linear Fresnel collector. Linear Fresnel architecture is of interest because it has features that are well suited for use with molten salt as a heat transfer fluid: the receiver is fixed (only the mirrors track), the receiver diameter is large (reducing risk of freeze events), and the total linear feet of receiver can be reduced due to the large aperture area. Using molten salt as a heat transfer fluid increases the allowable operating temperature of a collector field, and the cost of thermal storage is reduced in proportion to that increase in temperature. At the conclusion of this project, SkyFuel determined that the cost goals set forth in the contract could not be reasonably met. The performance of a Linear Fresnel collector is significantly less than that of a parabolic trough, in particular due to linear Fresnel’s large optical cosine losses. On an annual basis, the performance is 20 to 30% below that of a parabolic trough per unit area. The linear Fresnel collector and balance of system costs resulted in an LCOE of approximately 9.9¢/kWhr_{e}. Recent work by SkyFuel has resulted in a large aperture trough design (DSP Trough) with an LCOE value of 8.9 ¢/kWhr_{e} calculated with comparative financial terms and balance of plant costs (White 2011). Thus, even though the optimized linear Fresnel collector of our design has a lower unit cost than our optimized trough, it cannot overcome the reduction in annual performance.
FDATMOS16 non-linear partitioning and organic volatility distributions in urban aerosols
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Madronich, Sasha; Kleinman, Larry; Conley, Andrew; Lee-Taylor, Julie; Hodzic, A.; Aumont, Bernard
2015-12-17
Gas-to-particle partitioning of organic aerosols (OA) is represented in most models by Raoult’s law, and depends on the existing mass of particles into which organic gases can dissolve. This raises the possibility of non-linear response of particle-phase OA to the emissions of precursor volatile organic compounds (VOCs) that contribute to this partitioning mass. Implications for air quality management are evident: A strong non-linear dependence would suggest that reductions in VOC emission would have a more-than-proportionate benefit in lowering ambient OA concentrations. Chamber measurements on simple VOC mixtures generally confirm the non-linear scaling between OA and VOCs, usually stated as amore » mass-dependence of the measured OA yields. However, for realistic ambient conditions including urban settings, no single component dominates the composition of the organic particles, and deviations from linearity are presumed to be small. Here we re-examine the linearity question using volatility spectra from several sources: (1) chamber studies of selected aerosols, (2) volatility inferred for aerosols sampled in two megacities, Mexico City and Paris, and (3) an explicit chemistry model (GECKO-A). These few available volatility distributions suggest that urban OA may be only slightly super-linear, with most values of the sensitivity exponent in the range 1.1-1.3, also substantially lower than seen in chambers for some specific aerosols. Furthermore, the rather low values suggest that OA concentrations in megacities are not an inevitable convergence of non-linear effects, but can be addressed (much like in smaller urban areas) by proportionate reductions in emissions.« less
FDATMOS16 non-linear partitioning and organic volatility distributions in urban aerosols
Madronich, Sasha; Kleinman, Larry; Conley, Andrew; Lee-Taylor, Julie; Hodzic, A.; Aumont, Bernard
2015-12-17
Gas-to-particle partitioning of organic aerosols (OA) is represented in most models by Raoult’s law, and depends on the existing mass of particles into which organic gases can dissolve. This raises the possibility of non-linear response of particle-phase OA to the emissions of precursor volatile organic compounds (VOCs) that contribute to this partitioning mass. Implications for air quality management are evident: A strong non-linear dependence would suggest that reductions in VOC emission would have a more-than-proportionate benefit in lowering ambient OA concentrations. Chamber measurements on simple VOC mixtures generally confirm the non-linear scaling between OA and VOCs, usually stated as a mass-dependence of the measured OA yields. However, for realistic ambient conditions including urban settings, no single component dominates the composition of the organic particles, and deviations from linearity are presumed to be small. Here we re-examine the linearity question using volatility spectra from several sources: (1) chamber studies of selected aerosols, (2) volatility inferred for aerosols sampled in two megacities, Mexico City and Paris, and (3) an explicit chemistry model (GECKO-A). These few available volatility distributions suggest that urban OA may be only slightly super-linear, with most values of the sensitivity exponent in the range 1.1-1.3, also substantially lower than seen in chambers for some specific aerosols. Furthermore, the rather low values suggest that OA concentrations in megacities are not an inevitable convergence of non-linear effects, but can be addressed (much like in smaller urban areas) by proportionate reductions in emissions.
Xu, Wen-Sheng; Freed, Karl F.
2015-07-14
The lattice cluster theory (LCT) for semiflexible linear telechelic melts, developed in Paper I, is applied to examine the influence of chain stiffness on the average degree of self-assembly and the basic thermodynamic properties of linear telechelic polymer melts. Our calculations imply that chain stiffness promotes self-assembly of linear telechelic polymer melts that assemble on cooling when either polymer volume fraction ϕ or temperature T is high, but opposes self-assembly when both ϕ and T are sufficiently low. This allows us to identify a boundary line in the ϕ-T plane that separates two regions of qualitatively different influence of chain stiffness on self-assembly. The enthalpy and entropy of self-assembly are usually treated as adjustable parameters in classical Flory-Huggins type theories for the equilibrium self-assembly of polymers, but they are demonstrated here to strongly depend on chain stiffness. Moreover, illustrative calculations for the dependence of the entropy density of linear telechelic polymer melts on chain stiffness demonstrate the importance of including semiflexibility within the LCT when exploring the nature of glass formation in models of linear telechelic polymer melts.
NON-BAROTROPIC LINEAR ROSSBY WAVE INSTABILITY IN THREE-DIMENSIONAL DISKS
Lin, Min-Kai
2013-03-10
Astrophysical disks with localized radial structure, such as protoplanetary disks containing dead zones or gaps due to disk-planet interaction, may be subject to the non-axisymmetric Rossby wave instability (RWI) that leads to vortex formation. The linear instability has recently been demonstrated in three-dimensional (3D) barotropic disks. It is the purpose of this study to generalize the 3D linear problem to include an energy equation, thereby accounting for baroclinity in three dimensions. Linear stability calculations are presented for radially structured, vertically stratified, geometrically thin disks with non-uniform entropy distribution in both directions. Polytropic equilibria are considered but adiabatic perturbations assumed. The unperturbed disk has a localized radial density bump, making it susceptible to the RWI. The linearized fluid equations are solved numerically as a partial differential equation eigenvalue problem. Emphasis on the ease of method implementation is given. It is found that when the polytropic index is fixed and adiabatic index increased, non-uniform entropy has negligible effect on the RWI growth rate, but pressure and density perturbation magnitudes near a pressure enhancement increase away from the midplane. The associated meridional flow is also qualitatively changed from homentropic calculations. Meridional vortical motion is identified in the nonhomentropic linear solution, as well as in a nonlinear global hydrodynamic simulation of the RWI in an initially isothermal disk evolved adiabatically. Numerical results suggest that buoyancy forces play an important role in the internal flow of Rossby vortices.
Spherically symmetric analysis on open FLRW solution in non-linear massive gravity
Chiang, Chien-I; Izumi, Keisuke; Chen, Pisin E-mail: izumi@phys.ntu.edu.tw
2012-12-01
We study non-linear massive gravity in the spherically symmetric context. Our main motivation is to investigate the effect of helicity-0 mode which remains elusive after analysis of cosmological perturbation around an open Friedmann-Lemaitre-Robertson-Walker (FLRW) universe. The non-linear form of the effective energy-momentum tensor stemming from the mass term is derived for the spherically symmetric case. Only in the special case where the area of the two sphere is not deviated away from the FLRW universe, the effective energy momentum tensor becomes completely the same as that of cosmological constant. This opens a window for discriminating the non-linear massive gravity from general relativity (GR). Indeed, by further solving these spherically symmetric gravitational equations of motion in vacuum to the linear order, we obtain a solution which has an arbitrary time-dependent parameter. In GR, this parameter is a constant and corresponds to the mass of a star. Our result means that Birkhoff's theorem no longer holds in the non-linear massive gravity and suggests that energy can probably be emitted superluminously (with infinite speed) on the self-accelerating background by the helicity-0 mode, which could be a potential plague of this theory.
Study of a scattering shield in a high heat load monochromator...
Office of Scientific and Technical Information (OSTI)
Resource Type: Journal Article Resource Relation: Journal Name: Nucl. Instrum. Methods A; Journal Volume: 716; Journal Issue: 07, 2013 Research Org: Advanced Photon Source (APS), ...
Nonlinear and linear timescales near kinetic scales in solar wind turbulence
Matthaeus, W. H.; Wan, M.; Shay, M. A.; Oughton, S.; Osman, K. T.; Chapman, S. C.; Servidio, S.; Valentini, F.; Gary, S. P.; Roytershteyn, V.; Karimabadi, H.
2014-08-01
The application of linear kinetic treatments to plasma waves, damping, and instability requires favorable inequalities between the associated linear timescales and timescales for nonlinear (e.g., turbulence) evolution. In the solar wind these two types of timescales may be directly compared using standard Kolmogorov-style analysis and observational data. The estimated local (in scale) nonlinear magnetohydrodynamic cascade times, evaluated as relevant kinetic scales are approached, remain slower than the cyclotron period, but comparable to or faster than the typical timescales of instabilities, anisotropic waves, and wave damping. The variation with length scale of the turbulence timescales is supported by observations and simulations. On this basis the use of linear theory—which assumes constant parameters to calculate the associated kinetic rates—may be questioned. It is suggested that the product of proton gyrofrequency and nonlinear time at the ion gyroscales provides a simple measure of turbulence influence on proton kinetic behavior.
Weymann, Ireneusz
2015-05-07
We analyze the spin-dependent linear-response transport properties of double quantum dots strongly coupled to external ferromagnetic leads. By using the numerical renormalization group method, we determine the dependence of the linear conductance and tunnel magnetoresistance on the degree of spin polarization of the leads and the position of the double dot levels. We focus on the transport regime where the system exhibits the SU(4) Kondo effect. It is shown that the presence of ferromagnets generally leads the suppression of the linear conductance due to the presence of an exchange field. Moreover, the exchange field gives rise to a transition from the SU(4) to the orbital SU(2) Kondo effect. We also analyze the dependence of the tunnel magnetoresistance on the double dot levels' positions and show that it exhibits a very nontrivial behavior.
Physics with linear colliders in the TeV CM energy region
Bulos, F.; Cook, V.; Hinchliffe, I.; Lane, K.; Pellet, D.; Perl, M.; Seiden, A.; Wiedemann, H.
1982-07-01
From a technical point of view a linear collider of high energy and luminosity cannot be operated economically at the present date. A series of R and D efforts in different areas are required to produce the necessary technology for an economically feasible linear collider. No fundamental limits, however, have been found as yet that would prevent us from reaching the goals outlined in this report. Most of the critical component will be tested in a real like situation once the SLC comes into operation. Beyond that much R and D is required in rf-power sources to reduce the power consumption and in high gradient accelerating structures to minimize the required real estate and linear construction costs.
Large linear magnetoresistance in a GaAs/AlGaAs heterostructure
Aamir, Mohammed Ali Goswami, Srijit Ghosh, Arindam; Baenninger, Matthias; Farrer, Ian; Ritchie, David A.; Tripathi, Vikram; Pepper, Michael
2013-12-04
We report non-saturating linear magnetoresistance (MR) in a two-dimensional electron system (2DES) at a GaAs/AlGaAs heterointerface in the strongly insulating regime. We achieve this by driving the gate voltage below the pinch-off point of the device and operating it in the non-equilibrium regime with high source-drain bias. Remarkably, the magnitude of MR is as large as 500% per Tesla with respect to resistance at zero magnetic field, thus dwarfing most non-magnetic materials which exhibit this linearity. Its primary advantage over most other materials is that both linearity and the enormous magnitude are retained over a broad temperature range (0.3 K to 10 K), thus making it an attractive candidate for cryogenic sensor applications.
Russell, Steven J.; Carlsten, Bruce E.
2012-06-26
We will quickly go through the history of the non-linear transmission lines (NLTLs). We will describe how they work, how they are modeled and how they are designed. Note that the field of high power, NLTL microwave sources is still under development, so this is just a snap shot of their current state. Topics discussed are: (1) Introduction to solitons and the KdV equation; (2) The lumped element non-linear transmission line; (3) Solution of the KdV equation; (4) Non-linear transmission lines at microwave frequencies; (5) Numerical methods for NLTL analysis; (6) Unipolar versus bipolar input; (7) High power NLTL pioneers; (8) Resistive versus reactive load; (9) Non-lineaer dielectrics; and (10) Effect of losses.
Deterministic algorithms for 2-d convex programming and 3-d online linear programming
Chan, T.M.
1997-06-01
We present a deterministic algorithm for solving two-dimensional convex programs with a linear objective function. The algorithm requires O(k log k) primitive operations for k constraints; if a feasible point is given, the bound reduces to O(k log k/ log log k). As a consequence, we can decide whether k convex n-gons in the plane have a common intersection in O(k log n min (log k, log log n)) worst-case time. Furthermore, we can solve the three-dimensional online linear programming problem in o(log{sup 3} n) worst-case time per operation.
A Beam Driven Plasma-Wakefield Linear Collider: From Higgs Factory to
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Multi-TeV (Conference) | SciTech Connect Conference: A Beam Driven Plasma-Wakefield Linear Collider: From Higgs Factory to Multi-TeV Citation Details In-Document Search Title: A Beam Driven Plasma-Wakefield Linear Collider: From Higgs Factory to Multi-TeV Authors: Adli, E ; Delahaye, J.P. ; Gessner, S.J. ; Hogan, M.J. ; Raubenheimer, T. ; /SLAC ; An, W. ; Joshi, C. ; Mori, W. ; /UCLA, Los Angeles Publication Date: 2013-09-30 OSTI Identifier: 1074154 Report Number(s): SLAC-PUB-15426 DOE
Remarks on Hierarchic Control for a Linearized Micropolar Fluids System in Moving Domains
Jesus, Isaías Pereira de
2015-12-15
We study a Stackelberg strategy subject to the evolutionary linearized micropolar fluids equations in domains with moving boundaries, considering a Nash multi-objective equilibrium (non necessarily cooperative) for the “follower players” (as is called in the economy field) and an optimal problem for the leader player with approximate controllability objective. We will obtain the following main results: the existence and uniqueness of Nash equilibrium and its characterization, the approximate controllability of the linearized micropolar system with respect to the leader control and the existence and uniqueness of the Stackelberg–Nash problem, where the optimality system for the leader is given.
The feasibility of using methylene blue sensitized polyvinylalcohol film as a linear polarizer
Jyothilakshmi, K.; Anju, K. S.; Arathy, K.; John, Beena Mary; Krishna, P. B.; Sruthi, C. T.; Chacko, Maria
2014-01-28
Linear light polarizing films selectively transmit radiations vibrating along an electromagnetic radiation vector and selectively absorb radiations vibrating along a second electromagnetic radiation vector. It happens according to the anisotropy of the film . In the present study the polarization effects of methylene blue sensitized polyvinyl alcohol is investigated. The polarization effects on the dye concentration, heating and stretching of film also are evaluated.
High-efficiency acceleration in the laser wakefield by a linearly increasing plasma density
Dong, Kegong; Wu, Yuchi; Zhu, Bin; Zhang, Zhimeng; Zhao, Zongqing; Zhou, Weimin; Hong, Wei; Cao, Leifeng; Gu, Yuqiu
2014-12-15
The acceleration length and the peak energy of the electron beam are limited by the dephasing effect in the laser wakefield acceleration with uniform plasma density. Based on 2D-3V particle in cell simulations, the effects of a linearly increasing plasma density on the electron acceleration are investigated broadly. Comparing with the uniform plasma density, because of the prolongation of the acceleration length and the gradually increasing accelerating field due to the increasing plasma density, the electron beam energy is twice higher in moderate nonlinear wakefield regime. Because of the lower plasma density, the linearly increasing plasma density can also avoid the dark current caused by additional injection. At the optimal acceleration length, the electron energy can be increased from 350 MeV (uniform) to 760 MeV (linearly increasing) with the energy spread of 1.8%, the beam duration is 5 fs and the beam waist is 1.25 μm. This linearly increasing plasma density distribution can be achieved by a capillary with special gas-filled structure, and is much more suitable for experiment.
Production of Ar{sup q+} ions with a tandem linear Paul trap
Higaki, H. Nagayasu, K.; Iwai, T.; Ito, K.; Okamoto, H.
2015-06-29
A tandem linear Paul trap was used to create highly charged Argon ions by electron impact ionizations. By improving the operation scheme, the production of Ar{sup 4+} ions was confirmed. Possible improvements for the future experiments with laser cooled Ca{sup +} ions are suggested.
Damping of linear waves via ionization and recombination in homogeneous plasmas
Dodin, I. Y.; Fisch, N. J.
2010-11-15
An oscillation-center model is proposed that analytically describes transformation of an arbitrary homogeneous linear wave at gradual ionization and recombination in homogeneous plasma. For the case when either of the processes dominates, general adiabatic invariants are found, from which the wave energy is derived as a function of the frequency.
Higgs Coupling Measurements at a 1 TeV Linear Collider
Barklow, T
2003-12-18
Methods for extracting Higgs boson signals at a 1 TeV center-of-mass energy e{sup +}e{sup -} linear collider are described. In addition, estimates are given for the accuracy with which branching fractions can be measured for Higgs boson decays to b{bar b} WW, gg, and {gamma}{gamma}.
DOE Publishes CALiPER Report on Cost-Effectiveness of Linear (T8) LED Lamps
Broader source: Energy.gov [DOE]
The U.S. Department of Energy's CALiPER program has released Report 21.3, which is part of a series of investigations on linear LED lamps. Report 21.3 details a set of life-cycle cost simulations...
The Case for a 500 GeV e+e- Linear Collider
Baggers, J.; Baltay, C.; Barker, T.; Barklow, T.; Bauer, U.; Bolton, T.; Brau, J.; Breidenbach, M.; Burke, D.; Burrows, P.; Dixon, L.; Fisk, H.E.; Frey, R.; Gerdes, D.; Graf, D.; Grannis, P.; Haber, H.E.; Hearty, C.; Hertzbach, S.; Heusch, C.; Hewett, J.; Hollebeek, R.; Jacobsen, R.; Jaros, J.; Kamon, T.; Karlen, D.; Koltick, D.; Kronfeld, A.; Marciano, W.; Markiewicz, T.; Murayama, H.; Nauenberg, U.; Orr, L.; Paige, F.; Para, A.; Peskin, M. E.; Porter, F.; Riles, K.; Ronan, M.; Rosenberg, L.; Schumm, B.; Stroynowski, R.; Tkaczyk, S.; Turcot, A.S.; van Bibber, K.; van Kooten, R.; Wells, J.D.; Yamamoto, H.
2000-07-05
Several proposals are being developed around the world for an e+e- linear collider with an initial center of mass energy of 500 GeV. In this paper, we will discuss why a project of this type deserves priority as the next major initiative in high energy physics.
THE CASE FOR A 500 GEV E+E- LINEAR COLLIDER
BAGGER,J.; BALTAY,C.; ET AL; MARCIANO,W.; PAIGE,F.; TURCOT,A.S.; AMERICAN LINEAR COLLIDER WORKING GROUP
2000-06-30
There are now several proposals that have been put forward from around the world for an e{sup +}e{sup {minus}} linear collider with an initial center of mass energy of 500 GeV. In this paper, the authors discuss why a project of this type deserves priority as the next, major initiative in high energy physics.
Photoelectron linear accelerator for producing a low emittance polarized electron beam
Yu, David U.; Clendenin, James E.; Kirby, Robert E.
2004-06-01
A photoelectron linear accelerator for producing a low emittance polarized electric beam. The accelerator includes a tube having an inner wall, the inner tube wall being coated by a getter material. A portable, or demountable, cathode plug is mounted within said tube, the surface of said cathode having a semiconductor material formed thereon.
Linear motion device and method for inserting and withdrawing control rods
Smith, Jay E.
1984-01-01
A linear motion device, more specifically a control rod drive mechanism (CRDM) for inserting and withdrawing control rods into a reactor core, is capable of independently and sequentially positioning two sets of control rods with a single motor stator and rotor. The CRDM disclosed can control more than one control rod lead screw without incurring a substantial increase in the size of the mechanism.
Ye, Tianyu; Liu, Han -Chun; Wang, Zhuo; Wegscheider, W.; Mani, Ramesh G.
2015-10-09
A comparative study of the radiation-induced magnetoresistance oscillations in the high mobility GaAs/AlGaAs heterostructure two dimensional electron system (2DES) under linearly- and circularly- polarized microwave excitation indicates a profound difference in the response observed upon rotating the microwave launcher for the two cases, although circularly polarized microwave radiation induced magnetoresistance oscillations observed at low magnetic fields are similar to the oscillations observed with linearly polarized radiation. For the linearly polarized radiation, the magnetoresistive response is a strong sinusoidal function of the launcher rotation (or linear polarization) angle, θ. As a result, for circularly polarized radiation, the oscillatory magnetoresistive response is hardly sensitive to θ.
Hong Qin and Ronald C. Davidson
2011-07-19
In a linear trap confining a one-component nonneutral plasma, the external focusing force is a linear function of the configuration coordinates and/or the velocity coordinates. Linear traps include the classical Paul trap and the Penning trap, as well as the newly proposed rotating-radio- frequency traps and the Mobius accelerator. This paper describes a class of self-similar nonlinear solutions of nonneutral plasma in general time-dependent linear focusing devices, with self-consistent electrostatic field. This class of nonlinear solutions includes many known solutions as special cases.
Self-consistent field theory based molecular dynamics with linear system-size scaling
Richters, Dorothee; Khne, Thomas D.
2014-04-07
We present an improved field-theoretic approach to the grand-canonical potential suitable for linear scaling molecular dynamics simulations using forces from self-consistent electronic structure calculations. It is based on an exact decomposition of the grand canonical potential for independent fermions and does neither rely on the ability to localize the orbitals nor that the Hamilton operator is well-conditioned. Hence, this scheme enables highly accurate all-electron linear scaling calculations even for metallic systems. The inherent energy drift of Born-Oppenheimer molecular dynamics simulations, arising from an incomplete convergence of the self-consistent field cycle, is circumvented by means of a properly modified Langevin equation. The predictive power of the present approach is illustrated using the example of liquid methane under extreme conditions.
Voila: A visual object-oriented iterative linear algebra problem solving environment
Edwards, H.C.; Hayes, L.J.
1994-12-31
Application of iterative methods to solve a large linear system of equations currently involves writing a program which calls iterative method subprograms from a large software package. These subprograms have complex interfaces which are difficult to use and even more difficult to program. A problem solving environment specifically tailored to the development and application of iterative methods is needed. This need will be fulfilled by Voila, a problem solving environment which provides a visual programming interface to object-oriented iterative linear algebra kernels. Voila will provide several quantum improvements over current iterative method problem solving environments. First, programming and applying iterative methods is considerably simplified through Voila`s visual programming interface. Second, iterative method algorithm implementations are independent of any particular sparse matrix data structure through Voila`s object-oriented kernels. Third, the compile-link-debug process is eliminated as Voila operates as an interpreter.
Bailey, T S; Chang, J H; Warsa, J S; Adams, M L
2010-12-22
We present a new spatial discretization of the discrete-ordinates transport equation in two-dimensional Cartesian (X-Y) geometry for arbitrary polygonal meshes. The discretization is a discontinuous finite element method (DFEM) that utilizes piecewise bi-linear (PWBL) basis functions, which are formally introduced in this paper. We also present a series of numerical results on quadrilateral and polygonal grids and compare these results to a variety of other spatial discretizations that have been shown to be successful on these grid types. Finally, we note that the properties of the PWBL basis functions are such that the leading-order piecewise bi-linear discontinuous finite element (PWBLD) solution will satisfy a reasonably accurate diffusion discretization in the thick diffusion limit, making the PWBLD method a viable candidate for many different classes of transport problems.
Proceedings of the conference on computer codes and the linear accelerator community
Cooper, R.K.
1990-07-01
The conference whose proceedings you are reading was envisioned as the second in a series, the first having been held in San Diego in January 1988. The intended participants were those people who are actively involved in writing and applying computer codes for the solution of problems related to the design and construction of linear accelerators. The first conference reviewed many of the codes both extant and under development. This second conference provided an opportunity to update the status of those codes, and to provide a forum in which emerging new 3D codes could be described and discussed. The afternoon poster session on the second day of the conference provided an opportunity for extended discussion. All in all, this conference was felt to be quite a useful interchange of ideas and developments in the field of 3D calculations, parallel computation, higher-order optics calculations, and code documentation and maintenance for the linear accelerator community. A third conference is planned.
Linear magnetoresistance caused by mobility fluctuations in n-doped Cd3As2
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Narayanan, A.; Watson, M. D.; Blake, S. F.; Bruyant, N.; Drigo, L.; Chen, Y. L.; Prabhakaran, D.; Yan, B.; Felser, C.; Kong, T.; et al
2015-03-19
Cd3As2 is a candidate three-dimensional Dirac semimetal which has exceedingly high mobility and nonsaturating linear magnetoresistance that may be relevant for future practical applications. We report magnetotransport and tunnel diode oscillation measurements on Cd3As2, in magnetic fields up to 65 T and temperatures between 1.5 and 300 K. We find that the nonsaturating linear magnetoresistance persists up to 65 T and it is likely caused by disorder effects, as it scales with the high mobility rather than directly linked to Fermi surface changes even when approaching the quantum limit. As a result of the observed quantum oscillations, we determine themore » bulk three-dimensional Fermi surface having signatures of Dirac behavior with a nontrivial Berry phase shift, very light effective quasiparticle masses, and clear deviations from the band-structure predictions. In very high fields we also detect signatures of large Zeeman spin splitting (g~16).« less
Variational principle for linear stability of flowing plasmas in Hall magnetohydrodynamics
Hirota, M.; Yoshida, Z.; Hameiri, E.
2006-02-15
Linear stability of equilibrium states with flow is studied by means of the variational principle in Hall magnetohydrodynamics (MHD). The Lagrangian representation of the linearized Hall MHD equation is performed by considering special perturbations that preserves some constants of motion (the Casimir invariants). The resultant equation has a Hamiltonian structure which enables the variational principle. There is however some difficulties in showing the positive definiteness of the quadratic form in the presence of flow. The dynamically accessible variation is a more restricted class of perturbations which, by definition, preserves all the Casimir invariants. For such variations, the quadratic form (the second variation of Hamiltonian) can be positive definite. Some conditions for stability are derived by applying this variational principle to the double Beltrami equilibrium.
Estimation of Heavy Ion Densities From Linearly Polarized EMIC Waves At Earth
Kim, Eun-Hwa; Johnson, Jay R.; Lee, Dong-Hun
2014-02-24
Linearly polarized EMIC waves are expected to concentrate at the location where their wave frequency satisfies the ion-ion hybrid (IIH) resonance condition as the result of a mode conversion process. In this letter, we evaluate absorption coefficients at the IIH resonance in the Earth geosynchronous orbit for variable concentrations of helium and azimuthal and field-aligned wave numbers in dipole magnetic field. Although wave absorption occurs for a wide range of heavy ion concentration, it only occurs for a limited range of azimuthal and field-aligned wave numbers such that the IIH resonance frequency is close to, but not exactly the same as the crossover frequency. Our results suggest that, at L = 6.6, linearly polarized EMIC waves can be generated via mode conversion from the compressional waves near the crossover frequency. Consequently, the heavy ion concentration ratio can be estimated from observations of externally generated EMIC waves that have polarization.
Φ-Meson Photoproduction with Linearly Polarized Photons at Threshold Energies
Salamanca, Julian; Cole, Philip L
2007-10-01
The observables provided by linearly-polarized photons are of interest in delineating the contributions of the various hadronic processes giving rise to vector meson photoproduction. In particular, we describe how Φ-meson production affords an incisive tool for exploring the nature of the parity exchange at threshold energies, the strangeness content of proton, as well as extracting signatures for the violation of Okubo-Zweig-Iizuka observation (OZI rule). Our goal is to study the γp → Φp reaction, with Φ → K^{+}K^{-}, in the photon energy range of 1.7 to 2.1 GeV by using the Coherent Linear Bremsstrahlung Facility in Hall B of Jefferson Laboratory, Newport News, VA. The data were collected during the g8b run in the summer of 2005.
{phi}-Meson Photoproduction with Linearly Polarized Photons at Threshold Energies
Salamanca, Julian; Cole, Philip L.
2007-10-26
The observables provided by linearly-polarized photons are of interest in delineating the contributions of the various hadronic processes giving rise to vector meson photoproduction. In particular, we describe how {phi}-meson production affords an incisive tool for exploring the nature of the parity exchange at threshold energies, the strangeness content of proton, as well as extracting signatures for the violation of Okubo-Zweig-Iizuka observation (OZI rule). Our goal is to study the {gamma}-vectorp{yields}{phi}p reaction, with {phi}{yields}K{sup +}K{sup -}, in the photon energy range of 1.7 to 2.1 GeV by using the Coherent Linear Bremsstrahlung Facility in Hall B of Jefferson Laboratory, Newport News, VA. The data were collected during the g8b run in the summer of 2005.
Refining and end use study of coal liquids II - linear programming analysis
Lowe, C.; Tam, S.
1995-12-31
A DOE-funded study is underway to determine the optimum refinery processing schemes for producing transportation fuels that will meet CAAA regulations from direct and indirect coal liquids. The study consists of three major parts: pilot plant testing of critical upgrading processes, linear programming analysis of different processing schemes, and engine emission testing of final products. Currently, fractions of a direct coal liquid produced form bituminous coal are being tested in sequence of pilot plant upgrading processes. This work is discussed in a separate paper. The linear programming model, which is the subject of this paper, has been completed for the petroleum refinery and is being modified to handle coal liquids based on the pilot plant test results. Preliminary coal liquid evaluation studies indicate that, if a refinery expansion scenario is adopted, then the marginal value of the coal liquid (over the base petroleum crude) is $3-4/bbl.
Solar receiver heliostat reflector having a linear drive and position information system
Horton, Richard H.
1980-01-01
A heliostat for a solar receiver system comprises an improved drive and control system for the heliostat reflector assembly. The heliostat reflector assembly is controllably driven in a predetermined way by a light-weight drive system so as to be angularly adjustable in both elevation and azimuth to track the sun and efficiently continuously reflect the sun's rays to a focal zone, i.e., heat receiver, which forms part of a solar energy utilization system, such as a solar energy fueled electrical power generation system. The improved drive system includes linear stepping motors which comprise low weight, low cost, electronic pulse driven components. One embodiment comprises linear stepping motors controlled by a programmed, electronic microprocessor. Another embodiment comprises a tape driven system controlled by a position control magnetic tape.
Explicit expressions for three-dimensional boundary integrals in linear elasticity
Nintcheu Fata, Sylvain
2011-01-01
On employing isoparametric, piecewise linear shape functions over a flat triangle, exact formulae are derived for all surface potentials involved in the numerical treatment of three-dimensional singular and hyper-singular boundary integral equations in linear elasticity. These formulae are valid for an arbitrary source point in space and are represented as analytical expressions along the edges of the integration triangle. They can be employed to solve integral equations defined on triangulated surfaces via a collocation method or may be utilized as analytical expressions for the inner integrals in a Galerkin technique. A numerical example involving a unit triangle and a source point located at various distances above it, as well as sample problems solved by a collocation boundary element method for the Lame equation are included to validate the proposed formulae.
Reliable clock estimation using linear weighted fusion based on pairwise broadcast synchronization
Shi, Xin Zhao, Xiangmo Hui, Fei Ma, Junyan Yang, Lan
2014-10-06
Clock synchronization in wireless sensor networks (WSNs) has been studied extensively in recent years and many protocols are put forward based on the point of statistical signal processing, which is an effective way to optimize accuracy. However, the accuracy derived from the statistical data can be improved mainly by sufficient packets exchange, which will consume the limited power resources greatly. In this paper, a reliable clock estimation using linear weighted fusion based on pairwise broadcast synchronization is proposed to optimize sync accuracy without expending additional sync packets. As a contribution, a linear weighted fusion scheme for multiple clock deviations is constructed with the collaborative sensing of clock timestamp. And the fusion weight is defined by the covariance of sync errors for different clock deviations. Extensive simulation results show that the proposed approach can achieve better performance in terms of sync overhead and sync accuracy.
El-Taibany, W. F. E-mail: eltaibany@hotmail.com; Selim, M. M.; Al-Abbasy, O. M.; El-Bedwehy, N. A.
2014-07-15
The propagation of both linear and nonlinear dust acoustic waves (DAWs) in an inhomogeneous magnetized collisional and warm dusty plasma (DP) consisting of Boltzmann ions, nonextensive electrons, and inertial dust particles is investigated. The number density gradients of all DP components besides the inhomogeneities of electrostatic potential and the initial dust fluid velocity are taken into account. The linear dispersion relation and a nonlinear modified Zakharov-Kusnetsov (MZK) equation governing the propagation of the three-dimensional DAWs are derived. The analytical solution of the MZK reveals the creation of both compressive and rarefactive DAW solitons in the proposed model. It is found that the inhomogeneity dimension parameter and the electron nonextensive parameter affect significantly the nonlinear DAW's amplitude, width, and Mach number. The relations of our findings with some astrophysical situations have been given.
Evolution of the design of a silicon tracker for the Linear Collider
Cooper, W.E.
2005-10-01
A design for the silicon tracker for SiD was proposed at the Victoria Linear Collider Workshop [1]. This paper describes development of that design by the SiD group into a baseline model for simulation studies. The design has been modified to take into account detector fabrication and servicing requirements, features specific to the vertex chamber, and detector elements in the region surrounding the silicon tracker.
Generation of Symmetric Dicke States of Remote Qubits with Linear Optics
Thiel, C.; Zanthier, J. von; Bastin, T.; Solano, E.; Agarwal, G. S.
2007-11-09
We propose a method for generating all symmetric Dicke states, either in the long-lived internal levels of N massive particles or in the polarization degrees of freedom of photonic qubits, using linear optical tools only. By means of a suitable multiphoton detection technique, erasing Welcher-Weg information, our proposed scheme allows the generation and measurement of an important class of entangled multiqubit states.
Quasi-linear heating and acceleration in bi-Maxwellian plasmas
Hellinger, Petr; Trávníček, Pavel M.
2013-12-15
Quasi-linear acceleration and heating rates are derived for drifting bi-Maxwellian distribution functions in a general nonrelativistic case for arbitrary wave vectors, propagation angles, and growth/damping rates. The heating rates in a proton-electron plasma due to ion-cyclotron/kinetic Alfvén and mirror waves for a wide range of wavelengths, directions of propagation, and growth or damping rates are explicitly computed.
Comparison of the extended linear {sigma} model and chiral perturbation theory
Alvarez, W.P.; Kubodera, K.; Myhrer, F.
2005-09-01
The pion-nucleon-scattering amplitudes are calculated in tree approximation with the use of the extended linear sigma model (ELSM) as well as heavy-baryon chiral perturbation theory (HB{chi}PT), and the nonrelativistic forms of the ELSM results are compared with those of HB{chi}PT. We find that the amplitudes obtained in ELSM do not agree with those derived from the more fundamental effective approach, HB{chi}PT.
Polarization observables from the photoproduction of omega-mesons using linearly polarized photons
D. Martinez, P.L. Cole, CLAS Collaboration
2012-04-01
We report on the photon beam asymmetry, {Sigma}, of the {omega} meson decaying into {pi}{sup +}, {pi}{sup -}, {pi}{sup 0} using a beam of linearly polarized photons in the photon energy region of E{sub {gamma}} = 1.9 GeV. These preliminary results are from the summer 2005 g8b dataset, which were collected with the CLAS detector in Hall B of Jefferson Lab.
Linearization of scan velocity of resonant vibrating-mirror beam deflectors
Yeung, Edward S.; Chen, Shun-Le
1991-01-15
A means and method for producing linerization of scan velocity of resonant vibrating-mirror beam deflectors in laser scanning system including presenting an elliptical convex surface to the scanning beam to reflect the scanning beam to the focal plane of the scanning line. The elliptical surface is shaped to produce linear velocity of the reflective scanning beam at the focal plane. Maximization of linerization is accomplished by considering sets of criteria for different scanning applications.
A modified post damping ring bunch compressor beamline for the TESLA linear collider
Philippe R.-G. Piot; Winfried Decking
2004-03-23
We propose a modified bunch compressor beamline, downstream of the damping ring, for the TESLA linear collider. This modified beamline uses a third harmonic radio-frequency section based on the 3.9 GHz superconducting cavity under development at Fermilab. In our design the beam deceleration is about {approx}50 MeV instead of {approx}450 MeV in the original design proposed.
DOE Publishes CALiPER Report on Cost-Effectiveness of Linear (T8) LED Lamps
Broader source: Energy.gov [DOE]
The U.S. Department of Energy's CALiPER program has released Report 21.3, which is part of a series of investigations on linear LED lamps. Report 21.3 details a set of life-cycle cost simulations that compared a two-lamp troffer using LED lamps (38W total power draw) or fluorescent lamps (51W total power draw) over a 10-year study period.
Orbit correction in a linear nonscaling fixed field alternating gradient accelerator
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Kelliher, D. J.; Machida, S.; Edmonds, C. S.; Kirkman, I. W.; Jones, J. K.; Muratori, B. D.; Garland, J. M.; Berg, J. S.
2014-11-20
In a linear non-scaling FFAG the large natural chromaticity of the machine results in a betatron tune that varies by several integers over the momentum range. In addition, orbit correction is complicated by the consequent variation of the phase advance between lattice elements. Here we investigate how the correction of multiple closed orbit harmonics allows correction of both the COD and the accelerated orbit distortion over the momentum range.
Orbit correction in a linear nonscaling fixed field alternating gradient accelerator
Kelliher, D. J.; Machida, S.; Edmonds, C. S.; Kirkman, I. W.; Jones, J. K.; Muratori, B. D.; Garland, J. M.; Berg, J. S.
2014-11-01
In a linear non-scaling FFAG the large natural chromaticity of the machine results in a betatron tune that varies by several integers over the momentum range. Orbit correction is complicated by the consequent variation of the phase advance between lattice elements. Here we investigate how the correction of multiple closed orbit harmonics allows correction of both the COD and the accelerated orbit distortion over the momentum range.
Brau, James E
2013-04-22
The U.S Linear Collider Detector R&D program, supported by the DOE and NSF umbrella grants to the University of Oregon, made significant advances on many critical aspects of the ILC detector program. Progress advanced on vertex detector sensor development, silicon and TPC tracking, calorimetry on candidate technologies, and muon detection, as well as on beamline measurements of luminosity, energy, and polarization.
Towards time-dependent current-density-functional theory in the non-linear regime
Escartn, J. M.; Vincendon, M.; Dinh, P. M.; Suraud, E.; Romaniello, P.; Reinhard, P.-G.
2015-02-28
Time-Dependent Density-Functional Theory (TDDFT) is a well-established theoretical approach to describe and understand irradiation processes in clusters and molecules. However, within the so-called adiabatic local density approximation (ALDA) to the exchange-correlation (xc) potential, TDDFT can show insufficiencies, particularly in violently dynamical processes. This is because within ALDA the xc potential is instantaneous and is a local functional of the density, which means that this approximation neglects memory effects and long-range effects. A way to go beyond ALDA is to use Time-Dependent Current-Density-Functional Theory (TDCDFT), in which the basic quantity is the current density rather than the density as in TDDFT. This has been shown to offer an adequate account of dissipation in the linear domain when the Vignale-Kohn (VK) functional is used. Here, we go beyond the linear regime and we explore this formulation in the time domain. In this case, the equations become very involved making the computation out of reach; we hence propose an approximation to the VK functional which allows us to calculate the dynamics in real time and at the same time to keep most of the physics described by the VK functional. We apply this formulation to the calculation of the time-dependent dipole moment of Ca, Mg and Na{sub 2}. Our results show trends similar to what was previously observed in model systems or within linear response. In the non-linear domain, our results show that relaxation times do not decrease with increasing deposited excitation energy, which sets some limitations to the practical use of TDCDFT in such a domain of excitations.
Linear motion device and method for inserting and withdrawing control rods
Smith, J.E.
Disclosed is a linear motion device and more specifically a control rod drive mechanism (CRDM) for inserting and withdrawing control rods into a reactor core. The CRDM and method disclosed is capable of independently and sequentially positioning two sets of control rods with a single motor stator and rotor. The CRDM disclosed can control more than one control rod lead screw without incurring a substantial increase in the size of the mechanism.
A spectral analysis of the domain decomposed Monte Carlo method for linear systems
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Slattery, Stuart R.; Evans, Thomas M.; Wilson, Paul P. H.
2015-09-08
The domain decomposed behavior of the adjoint Neumann-Ulam Monte Carlo method for solving linear systems is analyzed using the spectral properties of the linear oper- ator. Relationships for the average length of the adjoint random walks, a measure of convergence speed and serial performance, are made with respect to the eigenvalues of the linear operator. In addition, relationships for the effective optical thickness of a domain in the decomposition are presented based on the spectral analysis and diffusion theory. Using the effective optical thickness, the Wigner rational approxi- mation and the mean chord approximation are applied to estimate the leakagemore » frac- tion of random walks from a domain in the decomposition as a measure of parallel performance and potential communication costs. The one-speed, two-dimensional neutron diffusion equation is used as a model problem in numerical experiments to test the models for symmetric operators with spectral qualities similar to light water reactor problems. We find, in general, the derived approximations show good agreement with random walk lengths and leakage fractions computed by the numerical experiments.« less
Effective Yukawa couplings and flavor-changing Higgs boson decays at linear colliders
Gabrielli, E.; Mele, B.
2011-04-01
We analyze the advantages of a linear-collider program for testing a recent theoretical proposal where the Higgs boson Yukawa couplings are radiatively generated, keeping unchanged the standard-model mechanism for electroweak-gauge-symmetry breaking. Fermion masses arise at a large energy scale through an unknown mechanism, and the standard model at the electroweak scale is regarded as an effective field theory. In this scenario, Higgs boson decays into photons and electroweak gauge-boson pairs are considerably enhanced for a light Higgs boson, which makes a signal observation at the LHC straightforward. On the other hand, the clean environment of a linear collider is required to directly probe the radiative fermionic sector of the Higgs boson couplings. Also, we show that the flavor-changing Higgs boson decays are dramatically enhanced with respect to the standard model. In particular, we find a measurable branching ratio in the range (10{sup -4}-10{sup -3}) for the decay H{yields}bs for a Higgs boson lighter than 140 GeV, depending on the high-energy scale where Yukawa couplings vanish. We present a detailed analysis of the Higgs boson production cross sections at linear colliders for interesting decay signatures, as well as branching-ratio correlations for different flavor-conserving/nonconserving fermionic decays.
Subsurface failure in spherical bodies. A formation scenario for linear troughs on Vesta’s surface
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Stickle, Angela M.; Schultz, P. H.; Crawford, D. A.
2014-10-13
Many asteroids in the Solar System exhibit unusual, linear features on their surface. The Dawn mission recently observed two sets of linear features on the surface of the asteroid 4 Vesta. Geologic observations indicate that these features are related to the two large impact basins at the south pole of Vesta, though no specific mechanism of origin has been determined. Furthermore, the orientation of the features is offset from the center of the basins. Experimental and numerical results reveal that the offset angle is a natural consequence of oblique impacts into a spherical target. We demonstrate that a set ofmore » shear planes develops in the subsurface of the body opposite to the point of first contact. Moreover, these subsurface failure zones then propagate to the surface under combined tensile-shear stress fields after the impact to create sets of approximately linear faults on the surface. Comparison between the orientation of damage structures in the laboratory and failure regions within Vesta can be used to constrain impact parameters (e.g., the approximate impact point and likely impact trajectory).« less
Linear beam-beam tune shift calculations for the Tevatron Collider
Johnson, D.
1989-01-12
A realistic estimate of the linear beam-beam tune shift is necessary for the selection of an optimum working point in the tune diagram. Estimates of the beam-beam tune shift using the ''Round Beam Approximation'' (RBA) have over estimated the tune shift for the Tevatron. For a hadron machine with unequal lattice functions and beam sizes, an explicit calculation using the beam size at the crossings is required. Calculations for various Tevatron lattices used in Collider operation are presented. Comparisons between the RBA and the explicit calculation, for elliptical beams, are presented. This paper discusses the calculation of the linear tune shift using the program SYNCH. Selection of a working point is discussed. The magnitude of the tune shift is influenced by the choice of crossing points in the lattice as determined by the pbar ''cogging effects''. Also discussed is current cogging procedures and presents results of calculations for tune shifts at various crossing points in the lattice. Finally, a comparison of early pbar tune measurements with the present linear tune shift calculations is presented. 17 refs., 13 figs., 3 tabs.
Influence of a high vacuum on the precise positioning using an ultrasonic linear motor
Kim, Wan-Soo; Lee, Dong-Jin; Lee, Sun-Kyu
2011-01-15
This paper presents an investigation of the ultrasonic linear motor stage for use in a high vacuum environment. The slider table is driven by the hybrid bolt-clamped Langevin-type ultrasonic linear motor, which is excited with its different modes of natural frequencies in both lateral and longitudinal directions. In general, the friction behavior in a vacuum environment becomes different from that in an environment of atmospheric pressure and this difference significantly affects the performance of the ultrasonic linear motor. In this paper, to consistently provide stable and high power of output in a high vacuum, frequency matching was conducted. Moreover, to achieve the fine control performance in the vacuum environment, a modified nominal characteristic trajectory following control method was adopted. Finally, the stage was operated under high vacuum condition, and the operating performances were investigated compared with that of a conventional PI compensator. As a result, robustness of positioning was accomplished in a high vacuum condition with nanometer-level accuracy.
CALiPER Report 21.3. Cost Effectiveness of Linear (T8) LED Lamps
2014-05-01
Meeting performance expectations is important for driving adoption of linear LED lamps, but cost-effectiveness may be an overriding factor in many cases. Linear LED lamps cost more initially than fluorescent lamps, but energy and maintenance savings may mean that the life-cycle cost is lower. This report details a series of life-cycle cost simulations that compared a two-lamp troffer using LED lamps (38 W total power draw) or fluorescent lamps (51 W total power draw) over a 10-year study period. Variables included LED system cost ($40, $80, or $120), annual operating hours (2,000 hours or 4,000 hours), LED installation time (15 minutes or 30 minutes), and melded electricity rate ($0.06/kWh, $0.12/kWh, $0.18/kWh, or $0.24/kWh). A full factorial of simulations allows users to interpolate between these values to aid in making rough estimates of economic feasibility for their own projects. In general, while their initial cost premium remains high, linear LED lamps are more likely to be cost-effective when electric utility rates are higher than average and hours of operation are long, and if their installation time is shorter.
CALiPER Report 21.3: Cost-Effectiveness of Linear (T8) LED Lamps
Miller, Naomi J.; Perrin, Tess E.; Royer, Michael P.
2014-05-27
Meeting performance expectations is important for driving adoption of linear LED lamps, but cost-effectiveness may be an overriding factor in many cases. Linear LED lamps cost more initially than fluorescent lamps, but energy and maintenance savings may mean that the life-cycle cost is lower. This report details a series of life-cycle cost simulations that compared a two-lamp troffer using LED lamps (38 W total power draw) or fluorescent lamps (51 W total power draw) over a 10-year study period. Variables included LED system cost ($40, $80, or $120), annual operating hours (2,000 hours or 4,000 hours), LED installation time (15 minutes or 30 minutes), and melded electricity rate ($0.06/kWh, $0.12/kWh, $0.18/kWh, or $0.24/kWh). A full factorial of simulations allows users to interpolate between these values to aid in making rough estimates of economic feasibility for their own projects. In general, while their initial cost premium remains high, linear LED lamps are more likely to be cost-effective when electric utility rates are higher than average and hours of operation are long, and if their installation time is shorter.
Linear dependence of surface expansion speed on initial plasma temperature in warm dense matter
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Bang, Woosuk; Albright, Brian James; Bradley, Paul Andrew; Vold, Erik Lehman; Boettger, Jonathan Carl; Fernández, Juan Carlos
2016-07-12
Recent progress in laser-driven quasi-monoenergetic ion beams enabled the production of uniformly heated warm dense matter. Matter heated rapidly with this technique is under extreme temperatures and pressures, and promptly expands outward. While the expansion speed of an ideal plasma is known to have a square-root dependence on temperature, computer simulations presented here show a linear dependence of expansion speed on initial plasma temperature in the warm dense matter regime. The expansion of uniformly heated 1–100 eV solid density gold foils was modeled with the RAGE radiation-hydrodynamics code, and the average surface expansion speed was found to increase linearly withmore » temperature. The origin of this linear dependence is explained by comparing predictions from the SESAME equation-of-state tables with those from the ideal gas equation-of-state. In conclusion, these simulations offer useful insight into the expansion of warm dense matter and motivate the application of optical shadowgraphy for temperature measurement.« less
Subsurface failure in spherical bodies. A formation scenario for linear troughs on Vestas surface
Stickle, Angela M.; Schultz, P. H.; Crawford, D. A.
2014-10-13
Many asteroids in the Solar System exhibit unusual, linear features on their surface. The Dawn mission recently observed two sets of linear features on the surface of the asteroid 4 Vesta. Geologic observations indicate that these features are related to the two large impact basins at the south pole of Vesta, though no specific mechanism of origin has been determined. Furthermore, the orientation of the features is offset from the center of the basins. Experimental and numerical results reveal that the offset angle is a natural consequence of oblique impacts into a spherical target. We demonstrate that a set of shear planes develops in the subsurface of the body opposite to the point of first contact. Moreover, these subsurface failure zones then propagate to the surface under combined tensile-shear stress fields after the impact to create sets of approximately linear faults on the surface. Comparison between the orientation of damage structures in the laboratory and failure regions within Vesta can be used to constrain impact parameters (e.g., the approximate impact point and likely impact trajectory).
Bit error rate tester using fast parallel generation of linear recurring sequences
Pierson, Lyndon G.; Witzke, Edward L.; Maestas, Joseph H.
2003-05-06
A fast method for generating linear recurring sequences by parallel linear recurring sequence generators (LRSGs) with a feedback circuit optimized to balance minimum propagation delay against maximal sequence period. Parallel generation of linear recurring sequences requires decimating the sequence (creating small contiguous sections of the sequence in each LRSG). A companion matrix form is selected depending on whether the LFSR is right-shifting or left-shifting. The companion matrix is completed by selecting a primitive irreducible polynomial with 1's most closely grouped in a corner of the companion matrix. A decimation matrix is created by raising the companion matrix to the (n*k).sup.th power, where k is the number of parallel LRSGs and n is the number of bits to be generated at a time by each LRSG. Companion matrices with 1's closely grouped in a corner will yield sparse decimation matrices. A feedback circuit comprised of XOR logic gates implements the decimation matrix in hardware. Sparse decimation matrices can be implemented with minimum number of XOR gates, and therefore a minimum propagation delay through the feedback circuit. The LRSG of the invention is particularly well suited to use as a bit error rate tester on high speed communication lines because it permits the receiver to synchronize to the transmitted pattern within 2n bits.
A Novel MagPipe Pipeline transportation system using linear motor drives
Fang, J.R.; Montgomery, D.B.; Roderick, L.
2009-11-15
A novel capsule pipeline transportation system using linear motor drives, called Magplane MagPipe, is under development with the intention to replace trucks and railways for hauling materials from the mine to the rail head, power plant, or processing plant with reduced operating cost and energy consumption. The initial demonstration of a MagPipe line in Inner Mongolia will be a 500-m-long double-pipe coal transport system with the design transportation capacity of 3 Mega-Mg per year. The pipeline consists of 6-m-long plastic pipe modules with an I-beam suspension system inside the pipe to carry sets of five coupled capsules. The pipe will also contain noncontinuous motor winding modules spaced at 50-m intervals. A set of Halbach-arrayed permanent magnets on the bottom of the capsules interact with the linear motor windings to provide propulsion. The motor is driven by variable frequency drives outside the pipe to control the speed. This paper briefly describes the overall MagPipe pipeline transportation system, including the preliminary conclusions of the linear synchronous motor analysis.
MULTIPASS MUON RLA RETURN ARCS BASED ON LINEAR COMBINED-FUNCTION MAGNETS
Vasiliy Morozov, Alex Bogacz, Yves Roblin, Kevin Beard
2011-09-01
Recirculating Linear Accelerators (RLA) are an efficient way of accelerating short-lived muons to the multi-GeV energies required for Neutrino Factories and TeV energies required for Muon Colliders. In this paper we present a design of a two-pass RLA return arc based on linear combined function magnets, in which both charge muons with momenta different by a factor of two are transported through the same string of magnets. The arc is composed of 60{sup o}-bending symmetric super cells allowing for a simple arc geometry closing. By adjusting the dipole and quadrupole components of the combined-function magnets, each super cell is designed to be achromatic and to have zero initial and final periodic orbit offsets for both muon momenta. Such a design provides a greater compactness than, for instance, an FFAG lattice with its regular alternating bends and is expected to possess a large dynamic aperture characteristic of linear-field lattices.
Robust parallel iterative solvers for linear and least-squares problems, Final Technical Report
Saad, Yousef
2014-01-16
The primary goal of this project is to study and develop robust iterative methods for solving linear systems of equations and least squares systems. The focus of the Minnesota team is on algorithms development, robustness issues, and on tests and validation of the methods on realistic problems. 1. The project begun with an investigation on how to practically update a preconditioner obtained from an ILU-type factorization, when the coefficient matrix changes. 2. We investigated strategies to improve robustness in parallel preconditioners in a specific case of a PDE with discontinuous coefficients. 3. We explored ways to adapt standard preconditioners for solving linear systems arising from the Helmholtz equation. These are often difficult linear systems to solve by iterative methods. 4. We have also worked on purely theoretical issues related to the analysis of Krylov subspace methods for linear systems. 5. We developed an effective strategy for performing ILU factorizations for the case when the matrix is highly indefinite. The strategy uses shifting in some optimal way. The method was extended to the solution of Helmholtz equations by using complex shifts, yielding very good results in many cases. 6. We addressed the difficult problem of preconditioning sparse systems of equations on GPUs. 7. A by-product of the above work is a software package consisting of an iterative solver library for GPUs based on CUDA. This was made publicly available. It was the first such library that offers complete iterative solvers for GPUs. 8. We considered another form of ILU which blends coarsening techniques from Multigrid with algebraic multilevel methods. 9. We have released a new version on our parallel solver - called pARMS [new version is version 3]. As part of this we have tested the code in complex settings - including the solution of Maxwell and Helmholtz equations and for a problem of crystal growth.10. As an application of polynomial preconditioning we considered the
DOE Publishes CALiPER Report on Linear (T8) LED Lamps in a 2x4...
Linear (T8) LED Lamps in a 2x4 K12-Lensed Troffer DOE Publishes CALiPER Report on Linear (T8) LED Lamps in a 2x4 K12-Lensed Troffer May 2, 2014 - 4:48pm Addthis The U.S. Department ...
Size reduction of high- and low-moisture corn stalks by linear knife grid system
Womac, A.R. [University of Tennessee; Igathinathane, C. [Mississippi State University (MSU); Sokhansanj, Shahabaddine [ORNL; Narayan, S. [First American Scientific Co.
2009-04-01
High- and low-moisture corn stalks were tested using a linear knife grid size reduction device developed for first-stage size reduction. The device was used in conjunction with a universal test machine that quantified shearing stress and energy characteristics for forcing a bed of corn stalks through a grid of sharp knives. No published engineering performance data for corn stover with similar devices are available to optimize performance; however, commercial knife grid systems exist for forage size reduction. From the force displacement data, mean and maximum ultimate shear stresses, cumulative and peak mass-based cutting energies for corn stalks, and mean new surface area-based cutting energies were determined from 4 5 refill runs at two moisture contents (78.8% and 11.3% wet basis), three knife grid spacings (25.4, 50.8, and 101.6 mm), and three bed depths (50.8, 101.6, and 152.4 mm). In general, the results indicated that peak failure load, ultimate shear stress, and cutting energy values varied directly with bed depth and inversely with knife grid spacing. Mean separation analysis established that high- and low-moisture conditions and bed depths 101.6 mm did not differ significantly (P < 0.05) for ultimate stress and cutting energy values, but knife grid spacing were significantly different. Linear knife grid cutting energy requirements for both moisture conditions of corn stalks were much smaller than reported cutting energy requirements. Ultimate shear stress and cutting energy results of this research should aid the engineering design of commercial scale linear knife gird size reduction equipment for various biomass feedstocks.
ANALYSIS OF QUIET-SUN INTERNETWORK MAGNETIC FIELDS BASED ON LINEAR POLARIZATION SIGNALS
Orozco Suarez, D.; Bellot Rubio, L. R.
2012-05-20
We present results from the analysis of Fe I 630 nm measurements of the quiet Sun taken with the spectropolarimeter of the Hinode satellite. Two data sets with noise levels of 1.2 Multiplication-Sign 10{sup -3} and 3 Multiplication-Sign 10{sup -4} are employed. We determine the distribution of field strengths and inclinations by inverting the two observations with a Milne-Eddington model atmosphere. The inversions show a predominance of weak, highly inclined fields. By means of several tests we conclude that these properties cannot be attributed to photon noise effects. To obtain the most accurate results, we focus on the 27.4% of the pixels in the second data set that have linear polarization amplitudes larger than 4.5 times the noise level. The vector magnetic field derived for these pixels is very precise because both circular and linear polarization signals are used simultaneously. The inferred field strength, inclination, and filling factor distributions agree with previous results, supporting the idea that internetwork (IN) fields are weak and very inclined, at least in about one quarter of the area occupied by the IN. These properties differ from those of network fields. The average magnetic flux density and the mean field strength derived from the 27.4% of the field of view with clear linear polarization signals are 16.3 Mx cm{sup -2} and 220 G, respectively. The ratio between the average horizontal and vertical components of the field is approximately 3.1. The IN fields do not follow an isotropic distribution of orientations.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Guttenfelder, W.; Kaye, S. M.; Ren, Y.; Solomon, W.; Bell, R. E.; Candy, J.; Gerhardt, S. P.; LeBlanc, B. P.; Yuh, H.
2016-05-11
This paper presents quasi-linear gyrokinetic predictions of the Coriolis momentum pinch for low aspect-ratio National Spherical Torus Experiment (NSTX) H-modes where previous experimental measurements were focused. Local, linear calculations predict that in the region of interest (just outside the mid-radius) of these relatively high-beta plasmas, profiles are most unstable to microtearing modes that are only effective in transporting electron energy. However, sub-dominant electromagnetic and electrostaticballooning modes are also unstable, which are effective at transporting energy, particles, and momentum. The quasi-linear prediction of transport from these weaker ballooning modes, assuming they contribute transport in addition to that from microtearing modes inmore » a nonlinear turbulent state, leads to a very small or outward convection of momentum, inconsistent with the experimentally measured inward pinch, and opposite to predictions in conventional aspect ratio tokamaks. Additional predictions of a low beta L-mode plasma, unstable to more traditional electrostatic ion temperature gradient-trapped electron mode instability, show that the Coriolis pinch is inward but remains relatively weak and insensitive to many parameter variations. The weak or outward pinch predicted in NSTX plasmas appears to be at least partially correlated to changes in the parallel mode structure that occur at a finite beta and low aspect ratio, as discussed in previous theories. The only conditions identified where a stronger inward pinch is predicted occur either in the purely electrostatic limit or if the aspect ratio is increased. Lastly, as the Coriolis pinch cannot explain the measured momentum pinch, additional theoretical momentum transport mechanisms are discussed that may be potentially important.« less
Stiebel-Kalish, Hadas; Reich, Ehud; Gal, Lior; Rappaport, Zvi Harry; Nissim, Ouzi; Pfeffer, Raphael; Spiegelmann, Roberto
2012-02-01
Purpose: Meningiomas threatening the anterior visual pathways (AVPs) and not amenable for surgery are currently treated with multisession stereotactic radiotherapy. Stereotactic radiotherapy is available with a number of devices. The most ubiquitous include the gamma knife, CyberKnife, tomotherapy, and isocentric linear accelerator systems. The purpose of our study was to describe a case series of AVP meningiomas treated with linear accelerator fractionated stereotactic radiotherapy (FSRT) using the multiple, noncoplanar, dynamic conformal rotation paradigm and to compare the success and complication rates with those reported for other techniques. Patients and Methods: We included all patients with AVP meningiomas followed up at our neuro-ophthalmology unit for a minimum of 12 months after FSRT. We compared the details of the neuro-ophthalmologic examinations and tumor size before and after FSRT and at the end of follow-up. Results: Of 87 patients with AVP meningiomas, 17 had been referred for FSRT. Of the 17 patients, 16 completed >12 months of follow-up (mean 39). Of the 16 patients, 11 had undergone surgery before FSRT and 5 had undergone FSRT as first-line management. Tumor control was achieved in 14 of the 16 patients, with three meningiomas shrinking in size after RT. Two meningiomas progressed, one in an area that was outside the radiation field. The visual function had improved in 6 or stabilized in 8 of the 16 patients (88%) and worsened in 2 (12%). Conclusions: Linear accelerator fractionated RT using the multiple noncoplanar dynamic rotation conformal paradigm can be offered to patients with meningiomas that threaten the anterior visual pathways as an adjunct to surgery or as first-line treatment, with results comparable to those reported for other stereotactic RT techniques.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Serra-Crespo, Pablo; Dikhtiarenko, Alla; Stavitski, Eli; Juan-Alcañiz, Jana; Kapteijn, Freek; Coudert, François-Xavier; Gascon, Jorge
2014-03-24
Here we report a series of powder X-ray diffraction experiments performed on the soft porous crystals MIL-53(Al) and NH2-MIL-53(Al) in a diamond anvil cell under different pressurization media. Systematic refinements of the obtained powder patterns demonstrate that these materials expand along a specific direction while undergoing total volume reduction under an increasing hydrostatic pressure. The results confirm for the first time the negative linear compressibility behaviour of this family of materials, recently predicted from quantum chemical calculations.
Höhne, Jens
2014-01-29
In order to reduce the amount of greenhouse gas emissions, which are most likely the cause of substantial global warming, a reduction of overall energy consumption is crucial. Low frequency Gifford-McMahon and pulse tube cryocoolers are usually powered by a scroll compressor together with a rotary valve. It has been theoretically shown that the efficiency losses within the rotary valve can be close to 50%{sup 1}. In order to eliminate these losses we propose to use a low frequency linear compressor, which directly generates the pressure wave without using a rotary valve. First results of this development will be presented.
Serra-Crespo, Pablo; Dikhtiarenko, Alla; Stavitski, Eli; Juan-Alcaniz, Jana; Kapeteijn, Freek; Coudert, Francois-Xavier; Gascon, Jorge
2014-03-24
Here, we report a series of powder X-ray diffraction experiments performed on the soft porous crystals MIL-53(Al) and NH_{2}-MIL-53(Al) in a diamond anvil cell under different pressurization media. Systematic refinements of the obtained powder patterns demonstrate that these materials expand along a specific direction while undergoing total volume reduction under an increasing hydrostatic pressure. Our results confirm for the first time the negative linear compressibility behaviour of this family of materials, recently predicted from quantum chemical calculations.
Serra-Crespo, Pablo; Dikhtiarenko, Alla; Stavitski, Eli; Juan-Alcaniz, Jana; Kapteijn, Freek; Coudert, Francois-Xavier; Gascon, Jorge
2014-03-24
Here we report a series of powder X-ray diffraction experiments performed on the soft porous crystals MIL-53(Al) and NH_{2}-MIL-53(Al) in a diamond anvil cell under different pressurization media. Systematic refinements of the obtained powder patterns demonstrate that these materials expand along a specific direction while undergoing total volume reduction under an increasing hydrostatic pressure. Our results confirm for the first time the negative linear compressibility behaviour of this family of materials, recently predicted from quantum chemical calculations.
Parametric instability of plasmas produced by linearly polarized microwave pulsed fields
Shokri, B.; Ghorbanalilu, M.
2005-04-15
After analyzing the interaction of an intense linearly polarized microwave, field weaker than atomic field, with a dilute gas, the production of a plasma is studied. It is shown that the electron distribution function obtained is nonequilibrium and anisotropic. By considering the interaction of the high-frequency electric field with the produced plasma the dispersion relation of oscillations in the produced plasma is obtained. The parametric instability is studied for the produced plasma when instability frequency is higher than ion plasma frequency. Calculations show that the harmonic generation takes place in the produced plasma.
Calculation of voltage harmonic distortion caused by small non-linear loads
Hegazy, Y.G.; Salama, M.M.A.
1995-10-01
This paper presents an accurate method to evaluate the harmonic distortion in distribution systems. This method overcomes most of the drawbacks of the traditional methods. The main idea of the proposed method is to represent the harmonic effects of small non-linear loads by an equivalent large load. A case study is presented in the paper to illustrate the proposed method. The total harmonic distortion factor is evaluated at different busses of a distribution system using the proposed method. The results are then compared to those obtained using the traditional methods.
EXPLORING THE VARIABLE SKY WITH LINEAR. III. CLASSIFICATION OF PERIODIC LIGHT CURVES
Palaversa, Lovro; Eyer, Laurent; Rimoldini, Lorenzo; Ivezi?, eljko; Loebman, Sarah; Hunt-Walker, Nicholas; VanderPlas, Jacob; Westman, David; Becker, Andrew C.; Rudjak, Domagoj; Sudar, Davor; Boi?, Hrvoje; Galin, Mario; Kroflin, Andrea; Mesari?, Martina; Munk, Petra; Vrbanec, Dijana; Sesar, Branimir; Stuart, J. Scott; Srdo?, Gregor; and others
2013-10-01
We describe the construction of a highly reliable sample of ?7000 optically faint periodic variable stars with light curves obtained by the asteroid survey LINEAR across 10,000 deg{sup 2} of the northern sky. The majority of these variables have not been cataloged yet. The sample flux limit is several magnitudes fainter than most other wide-angle surveys; the photometric errors range from ?0.03 mag at r = 15 to ?0.20 mag at r = 18. Light curves include on average 250 data points, collected over about a decade. Using Sloan Digital Sky Survey (SDSS) based photometric recalibration of the LINEAR data for about 25 million objects, we selected ?200,000 most probable candidate variables with r < 17 and visually confirmed and classified ?7000 periodic variables using phased light curves. The reliability and uniformity of visual classification across eight human classifiers was calibrated and tested using a catalog of variable stars from the SDSS Stripe 82 region and verified using an unsupervised machine learning approach. The resulting sample of periodic LINEAR variables is dominated by 3900 RR Lyrae stars and 2700 eclipsing binary stars of all subtypes and includes small fractions of relatively rare populations such as asymptotic giant branch stars and SX Phoenicis stars. We discuss the distribution of these mostly uncataloged variables in various diagrams constructed with optical-to-infrared SDSS, Two Micron All Sky Survey, and Wide-field Infrared Survey Explorer photometry, and with LINEAR light-curve features. We find that the combination of light-curve features and colors enables classification schemes much more powerful than when colors or light curves are each used separately. An interesting side result is a robust and precise quantitative description of a strong correlation between the light-curve period and color/spectral type for close and contact eclipsing binary stars (? Lyrae and W UMa): as the color-based spectral type varies from K4 to F5, the median
Linear optics measurements and corrections using an AC dipole in RHIC
Wang, G.; Bai, M.; Yang, L.
2010-05-23
We report recent experimental results on linear optics measurements and corrections using ac dipole. In RHIC 2009 run, the concept of the SVD correction algorithm is tested at injection energy for both identifying the artificial gradient errors and correcting it using the trim quadrupoles. The measured phase beatings were reduced by 30% and 40% respectively for two dedicated experiments. In RHIC 2010 run, ac dipole is used to measure {beta}* and chromatic {beta} function. For the 0.65m {beta}* lattice, we observed a factor of 3 discrepancy between model and measured chromatic {beta} function in the yellow ring.
On linear groups of degree 2 over a finite commutative ring
Bashkirov, Evgenii L.; Eser, Hasan
2014-08-20
Let p > 3 be a prime number and F{sub p} be a field of p elements. Let K be a commutative and associative ring obtained by adjoining to F{sub p} an element α such that α satisfies a polynomial over F{sub p} and a polynomial of the least degree whose root is α can be written as a product of distinct polynomials irreducible over F{sub p}. We prove that the special linear group SL{sub 2}(K) is generated by two elementary transvections ( (table) ), ( (table) )
Electron acceleration by linearly polarized twisted laser pulse with narrow divergence
Vaziri, Mohammad Sohaily, Sozha; Golshani, Mojtaba; Bahrampour, Alireza
2015-03-15
We numerically investigate the vacuum electron acceleration by a high-intensity linearly polarized twisted laser pulse. It is shown that the inherent spiral structure of a Laguerre-Gaussian laser pulse leads to improvement in trapping and acceleration of an electron to energies of the order of GeV in the off-axis case. Also, it is demonstrated that by employing a proper choice of initial injection parameters, the high-energetic electrons with very small scattering angles can be produced.
Performance of Conduction Cooled Splittable Superconducting Magnet Package for Linear Accelerators
Kashikhin, Vladimire S.; Andreev, N.; Cheban, S.; DiMarco, J.; Kimura, N.; Makarov, A.; Orlov, Y.; Poloubotko. V., Poloubotko. V.; Tartaglia, M.; Yamamoto, A.
2015-01-01
New Linear Superconducting Accelerators need a superconducting magnet package installed inside SCRF Cryomodules to focus and steer electron or proton beams. A superconducting magnet package was designed and built as a collaborative effort of FNAL and KEK. The magnet package includes one quadrupole, and two dipole windings. It has a splittable in the vertical plane configuration, and features for conduction cooling. The magnet was successfully tested at room temperature, in a liquid He bath, and in a conduction cooling experiment. The paper describes the design and test results including: magnet cooling, training, and magnetic measurements by rotational coils. The effects of superconductor and iron yoke magnetization, hysteresis, and fringe fields are discussed.
Investigations of non-linear polymers as high performance lubricant additives
Robinson, Joshua W.; Bhattacharya, Priyanka; Qu, Jun; Bays, J. Timothy; Cosimbescu, Lelia
2015-03-22
Off-the-shelf available engine oils contain an assortment of additives that increase the performance of base oils and maximize the overall efficiency of the machine. With ever increasing requirements for fuel efficiency, the demand for novel materials that outperform older generations is also on the rise. One approach towards increasing overall efficiency is to reduce internal friction and wear in an engine. From an additive approach, this is typically achieved by altering the bulk oil’s viscosity at high temperatures via polymers. In general, the hydrodynamic volume of polymers increase (expand) at elevated temperatures and decrease (contract/deflate) with declining temperatures and this effect is enhanced be carefully designing specific structures and architectures. The natural thinning tendency of base oil with increasing temperatures is in part mitigated by the expansion of the macromolecules added, and the overall effect is decreasing the viscosity losses at high temperatures. Traditional polymer architectures vary from linear to dendritic, where linear polymers of the same chemical composition and molecular weight to its dendritic counterpart will undergo a more significant free volume change in solution with regards to temperature changes. This advantage has been exploited in the literature towards the production of viscosity modifiers. However, one major disadvantage of linear polymers is degradation due to mechanical shear forces and high temperatures causing a shorter additive lifetime. Dendrimers on the other hand are known to demonstrate superior robustness to shear degradation when compared to their respective linear counterparts. An additional advantage of the dendritic architecture is the ability to tailor the peripheral end-groups towards influencing polymer-solvent and/or polymer-surface interactions. Comb-burst hyperbranched polymers are a hybrid of the aforementioned architectures and provide several compromises between the traditional
Linear beam raster magnet driver based on H-bridge technique
Sinkine, Nikolai I.; Yan, Chen; Apeldoorn, Cornelis; Dail, Jeffrey Glenn; Wojcik, Randolph Frank; Gunning, William
2006-06-06
An improved raster magnet driver for a linear particle beam is based on an H-bridge technique. Four branches of power HEXFETs form a two-by-two switch. Switching the HEXFETs in a predetermined order and at the right frequency produces a triangular current waveform. An H-bridge controller controls switching sequence and timing. The magnetic field of the coil follows the shape of the waveform and thus steers the beam using a triangular rather than a sinusoidal waveform. The system produces a raster pattern having a highly uniform raster density distribution, eliminates target heating from non-uniform raster density distributions, and produces higher levels of beam current.
Method for linearizing deflection of a MEMS device using binary electrodes and voltage modulation
Horenstein, Mark N. [West Roxbury, MA
2008-06-10
A micromechanical device comprising one or more electronically movable structure sets comprising for each set a first electrode supported on a substrate and a second electrode supported substantially parallel from said first electrode. Said second electrode is movable with respect to said first electrode whereby an electric potential applied between said first and second electrodes causing said second electrode to move relative to said first electrode a distance X, (X), where X is a nonlinear function of said potential, (V). Means are provided for linearizing the relationship between V and X.
A free-piston Stirling engine/linear alternator controls and load interaction test facility
Rauch, J.S.; Kankam, M.D.; Santiago, W.; Madi, F.J.
1992-08-01
A test facility at LeRC was assembled for evaluating free-piston Stirling engine/linear alternator control options, and interaction with various electrical loads. This facility is based on a 'SPIKE' engine/alternator. The engine/alternator, a multi-purpose load system, a digital computer based load and facility control, and a data acquisition system with both steady-periodic and transient capability are described. Preliminary steady-periodic results are included for several operating modes of a digital AC parasitic load control. Preliminary results on the transient response to switching a resistive AC user load are discussed.
Stoustrup, Jakob; Pommer, Christian; Kliem, Wolfhard
2015-10-31
This paper deals with two stability aspects of linear systems of the form I ¨ x +B˙ x +Cx = 0 given by the triple (I;B;C). A general transformation scheme is given for a structure and Jordan form preserving transformation of the triple. We investigate how a system can be transformed by suitable choices of the transformation parameters into a new system (I;B1;C1) with a symmetrizable matrix C1. This procedure facilitates stability investigations. We also consider systems with a Hamiltonian spectrum which discloses marginal stability after a Jordan form preserving transformation.
Nie Liming; Xing Da; Yang Diwu; Zeng Lvming; Zhou Quan
2007-04-23
Current imaging modalities face challenges in clinical applications due to limitations in resolution or contrast. Microwave-induced thermoacoustic imaging may provide a complementary modality for medical imaging, particularly for detecting foreign objects due to their different absorption of electromagnetic radiation at specific frequencies. A thermoacoustic tomography system with a multielement linear transducer array was developed and used to detect foreign objects in tissue. Radiography and thermoacoustic images of objects with different electromagnetic properties, including glass, sand, and iron, were compared. The authors' results demonstrate that thermoacoustic imaging has the potential to become a fast method for surgical localization of occult foreign objects.
Measurements of Neutron Induced Cross Sections at the Oak Ridge Electron Linear Accelerator
Guber, K.H.; Harvey, J.A.; Hill, N.W.; Koehler, P.E.; Leal, L.C.; Sayer, R.O.; Spencer, R.R.
1999-09-20
We have used the Oak Ridge Electron Linear Accelerator (ORELA) to measure neutron total and the fission cross sections of ^{233}U in the energy range from 0.36 eV to ~700 keV. We report average fission and total cross sections. Also, we measured the neutron total cross sections of ^{27}Al and Natural chlorine as well as the capture cross section of Al over an energy range from 100 eV up to about 400 keV.
An object oriented design for high performance linear algebra on distributed memory architectures
Dongarra, J.J. |; Walker, D.W.; Pozo, R.
1993-12-31
We describe the design of ScaLAPACK++, an object oriented C++ library for implementing linear algebra computations on distributed memory multicomputers. This package, when complete, will support distributed dense, banded, sparse matrix operations for symmetric, positive-definite, and non-symmetric cases. In ScaLAPACK++ we have employed object oriented design methods to enchance scalability, portability, flexibility, and ease-of-use. We illustrate some of these points by describing the implementation of a right-looking LU factorization for dense systems in ScaLAPACK++.
Linear study of Rayleigh-Taylor instability in a diffusive quantum plasma
Momeni, Mahdi
2013-08-15
The linear Rayleigh-Taylor (RT) instability in an incompressible quantum plasma is investigated on the basis of quantum magnetohydrodynamic model. It is shown that the occurrence of RT instability depends on density-temperature inhomogeneity (characteristic lengths) on one hand, and the system layer size on the other. It is also observed that the combined effects of external magnetic field, diffusivity, and quantum pressure significantly modify the dispersion properties of system in both the parallel and perpendicular directions. For any case, the imaginary and real parts of dispersion relation are presented and the possibility and conditions for the instability growth rate are discussed.
Long-range corrected density functional theory with linearly-scaled HF exchange
Song, Jong-Won; Hirao, Kimihiko
2015-12-31
Long-range corrected density functional theory (LC-DFT) attracts many chemists’ attentions as a quantum chemical method to be applied to large molecular system and its property calculations. However, the expensive time cost to evaluate the long-range HF exchange is a big obstacle to be overcome to be applied to the large molecular systems and the solid state materials. Upon this problem, we propose a linear-scaling method of the HF exchange integration, in particular, for the LC-DFT hybrid functional.
Feng, G.; Deriy, B.; Wang, J.; Shang, H.; Xu, S.
2008-01-01
The APS booster ring uses ramping power supplies to power the sextupole, quadrupole, and dipole magnets as the beam energy ramps up linearly to 7 GeV. Due to the circuit topology used, those supplies are unable to follow the linear ramp to the desired accuracy. The best regulation achieved is 0.5% while 0.1 % is desired. In addition to the unsatisfying regulation, those supplies are sensitive to AC line perturbations and are not able to reject AC line noises higher than a few tens of Hertz. To improve the performance, a linear MOSFET regulation system using paralleled MOSFET devices in series with the power supply is proposed. The system uses a real-time current feedback loop to force the MOSFETs to work in the linear operation mode. By using this linear MOSFET regulator, the voltage drop on MOSFETs, and hence the voltage imposed on magnets, can be regulated very quickly. As a result, the regulation of the magnet current can be improved significantly. Experiments and simulation have been performed to verify the proposed method. Results show that, with the linear regulator, the current regulation can be improved to better than 0.1%. Because of the high bandwidth of the linear regulator, it can reduce the harmonic content in the output current as well as reject the AC line disturbance.
Amai, W.; Espinoza, J. Jr.; Fletcher, D.R.
1997-06-01
This Software Requirements Specification (SRS) describes the features to be provided by the software for the GIS-T/ISTEA Pooled Fund Study Phase C Linear Referencing Engine project. This document conforms to the recommendations of IEEE Standard 830-1984, IEEE Guide to Software Requirements Specification (Institute of Electrical and Electronics Engineers, Inc., 1984). The software specified in this SRS is a proof-of-concept implementation of the Linear Referencing Engine as described in the GIS-T/ISTEA pooled Fund Study Phase B Summary, specifically Sheet 13 of the Phase B object model. The software allows an operator to convert between two linear referencing methods and a datum network.
CALiPER Report 21.1. Linear (T8) Lamps in a 2x4 K12-Lensed Troffer
2014-04-01
This report focuses on the performance of the same 31 linear LED lamps operated in a typical troffer with a K12 prismatic lens. In general, luminaire efficacy is strongly dictated by lamp efficacy, but the optical system of the luminaire substantially reduces the differences between the luminous intensity distributions of the lamps. While the distributions in the luminaire are similar, the differences remain large enough that workplane illuminance uniformity may be reduced if linear LED lamps with a narrow distribution are used. At the same time, linear LED lamps with a narrower distribution result in slightly higher luminaire efficiency.
Linear motor drive system for continuous-path closed-loop position control of an object
Barkman, William E.
1980-01-01
A precision numerical controlled servo-positioning system is provided for continuous closed-loop position control of a machine slide or platform driven by a linear-induction motor. The system utilizes filtered velocity feedback to provide system stability required to operate with a system gain of 100 inches/minute/0.001 inch of following error. The filtered velocity feedback signal is derived from the position output signals of a laser interferometer utilized to monitor the movement of the slide. Air-bearing slides mounted to a stable support are utilized to minimize friction and small irregularities in the slideway which would tend to introduce positioning errors. A microprocessor is programmed to read command and feedback information and converts this information into the system following error signal. This error signal is summed with the negative filtered velocity feedback signal at the input of a servo amplifier whose output serves as the drive power signal to the linear motor position control coil.
Achieving large linear elasticity and high strength in bulk nanocompsite via synergistic effect
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Hao, Shijie; Cui, Lishan; Guo, Fangmin; Liu, Yinong; Shi, Xiaobin; Jiang, Daqiang; Brown, Dennis E.; Ren, Yang
2015-03-09
Elastic strain in bulk metallic materials is usually limited to only a fraction of 1%. Developing bulk metallic materials showing large linear elasticity and high strength has proven to be difficult. Here, based on the synergistic effect between nanowires and orientated martensite NiTi shape memory alloy, we developed an in-situ Nb nanowires -orientated martensitic NiTi matrix composite showing an ultra-large linear elastic strain of 4% and an ultrahigh yield strength of 1.8 GPa. This material also has a high mechanical energy storage efficiency of 96% and a high energy storage density of 36 J/cm³ that is almost one order ofmore » larger than that of spring steel. It is demonstrated that the synergistic effect allows the exceptional mechanical properties of nanowires to be harvested at macro scale and the mechanical properties of matrix to be greatly improved, resulting in these superior properties. This study provides new avenues for developing advanced composites with superior properties by using effective synergistic effect between components.« less
Achieving large linear elasticity and high strength in bulk nanocompsite via synergistic effect
Hao, Shijie; Cui, Lishan; Guo, Fangmin; Liu, Yinong; Shi, Xiaobin; Jiang, Daqiang; Brown, Dennis E.; Ren, Yang
2015-03-09
Elastic strain in bulk metallic materials is usually limited to only a fraction of 1%. Developing bulk metallic materials showing large linear elasticity and high strength has proven to be difficult. Here, based on the synergistic effect between nanowires and orientated martensite NiTi shape memory alloy, we developed an in-situ Nb nanowires -orientated martensitic NiTi matrix composite showing an ultra-large linear elastic strain of 4% and an ultrahigh yield strength of 1.8 GPa. This material also has a high mechanical energy storage efficiency of 96% and a high energy storage density of 36 J/cm³ that is almost one order of larger than that of spring steel. It is demonstrated that the synergistic effect allows the exceptional mechanical properties of nanowires to be harvested at macro scale and the mechanical properties of matrix to be greatly improved, resulting in these superior properties. This study provides new avenues for developing advanced composites with superior properties by using effective synergistic effect between components.
Djukanovic, M.; Babic, B.; Milosevic, B.; Sobajic, D.J.; Pao, Y.H. |
1996-05-01
In this paper the blending/transloading facilities are modeled using an interactive fuzzy linear programming (FLP), in order to allow the decision-maker to solve the problem of uncertainty of input information within the fuel scheduling optimization. An interactive decision-making process is formulated in which decision-maker can learn to recognize good solutions by considering all possibilities of fuzziness. The application of the fuzzy formulation is accompanied by a careful examination of the definition of fuzziness, appropriateness of the membership function and interpretation of results. The proposed concept provides a decision support system with integration-oriented features, whereby the decision-maker can learn to recognize the relative importance of factors in the specific domain of optimal fuel scheduling (OFS) problem. The formulation of a fuzzy linear programming problem to obtain a reasonable nonfuzzy solution under consideration of the ambiguity of parameters, represented by fuzzy numbers, is introduced. An additional advantage of the FLP formulation is its ability to deal with multi-objective problems.
SLFP: A stochastic linear fractional programming approach for sustainable waste management
Zhu, H.; Huang, G.H.
2011-12-15
Highlights: > A new fractional programming (SLFP) method is developed for waste management. > SLFP can solve ratio optimization problems associated with random inputs. > A case study of waste flow allocation demonstrates its applicability. > SLFP helps compare objectives of two aspects and reflect system efficiency. > This study supports in-depth analysis of tradeoffs among multiple system criteria. - Abstract: A stochastic linear fractional programming (SLFP) approach is developed for supporting sustainable municipal solid waste management under uncertainty. The SLFP method can solve ratio optimization problems associated with random information, where chance-constrained programming is integrated into a linear fractional programming framework. It has advantages in: (1) comparing objectives of two aspects, (2) reflecting system efficiency, (3) dealing with uncertainty expressed as probability distributions, and (4) providing optimal-ratio solutions under different system-reliability conditions. The method is applied to a case study of waste flow allocation within a municipal solid waste (MSW) management system. The obtained solutions are useful for identifying sustainable MSW management schemes with maximized system efficiency under various constraint-violation risks. The results indicate that SLFP can support in-depth analysis of the interrelationships among system efficiency, system cost and system-failure risk.
Benini, Marco Dappiaggi, Claudio; Murro, Simone
2014-08-01
We discuss the quantization of linearized gravity on globally hyperbolic, asymptotically flat, vacuum spacetimes, and the construction of distinguished states which are both of Hadamard form and invariant under the action of all bulk isometries. The procedure, we follow, consists of looking for a realization of the observables of the theory as a sub-algebra of an auxiliary, non-dynamical algebra constructed on future null infinity ??. The applicability of this scheme is tantamount to proving that a solution of the equations of motion for linearized gravity can be extended smoothly to ??. This has been claimed to be possible provided that a suitable gauge fixing condition, first written by Geroch and Xanthopoulos [Asymptotic simplicity is stable, J. Math. Phys. 19, 714 (1978)], is imposed. We review its definition critically, showing that there exists a previously unnoticed obstruction in its implementation leading us to introducing the concept of radiative observables. These constitute an algebra for which a Hadamard state induced from null infinity and invariant under the action of all spacetime isometries exists and it is explicitly constructed.
CONDUCTION IN LOW MACH NUMBER FLOWS. I. LINEAR AND WEAKLY NONLINEAR REGIMES
Lecoanet, Daniel; Brown, Benjamin P.; Zweibel, Ellen G.; Burns, Keaton J.; Oishi, Jeffrey S.; Vasil, Geoffrey M.
2014-12-20
Thermal conduction is an important energy transfer and damping mechanism in astrophysical flows. Fourier's law, in which the heat flux is proportional to the negative temperature gradient, leading to temperature diffusion, is a well-known empirical model of thermal conduction. However, entropy diffusion has emerged as an alternative thermal conduction model, despite not ensuring the monotonicity of entropy. This paper investigates the differences between temperature and entropy diffusion for both linear internal gravity waves and weakly nonlinear convection. In addition to simulating the two thermal conduction models with the fully compressible Navier-Stokes equations, we also study their effects in the reduced ''soundproof'' anelastic and pseudoincompressible (PI) equations. We find that in the linear and weakly nonlinear regime, temperature and entropy diffusion give quantitatively similar results, although there are some larger errors in the PI equations with temperature diffusion due to inaccuracies in the equation of state. Extrapolating our weakly nonlinear results, we speculate that differences between temperature and entropy diffusion might become more important for strongly turbulent convection.
Linear analysis on the growth of non-spherical perturbations in supersonic accretion flows
Takahashi, Kazuya; Yamada, Shoichi
2014-10-20
We analyzed the growth of non-spherical perturbations in supersonic accretion flows. We have in mind an application to the post-bounce phase of core-collapse supernovae (CCSNe). Such non-spherical perturbations have been suggested by a series of papers by Arnett, who has numerically investigated violent convections in the outer layers of pre-collapse stars. Moreover, Couch and Ott demonstrated in their numerical simulations that such perturbations may lead to a successful supernova even for a progenitor that fails to explode without fluctuations. This study investigated the linear growth of perturbations during the infall onto a stalled shock wave. The linearized equations are solved as an initial and boundary value problem with the use of a Laplace transform. The background is a Bondi accretion flow whose parameters are chosen to mimic the 15 M {sub ☉} progenitor model by Woosley and Heger, which is supposed to be a typical progenitor of CCSNe. We found that the perturbations that are given at a large radius grow as they flow down to the shock radius; the density perturbations can be amplified by a factor of 30, for example. We analytically show that the growth rate is proportional to l, the index of the spherical harmonics. We also found that the perturbations oscillate in time with frequencies that are similar to those of the standing accretion shock instability. This may have an implication for shock revival in CCSNe, which will be investigated in our forthcoming paper in more detail.
Linear-scaling implementation of the direct random-phase approximation
Kllay, Mihly
2015-05-28
We report the linear-scaling implementation of the direct random-phase approximation (dRPA) for closed-shell molecular systems. As a bonus, linear-scaling algorithms are also presented for the second-order screened exchange extension of dRPA as well as for the second-order MllerPlesset (MP2) method and its spin-scaled variants. Our approach is based on an incremental scheme which is an extension of our previous local correlation method [Rolik et al., J. Chem. Phys. 139, 094105 (2013)]. The approach extensively uses local natural orbitals to reduce the size of the molecular orbital basis of local correlation domains. In addition, we also demonstrate that using natural auxiliary functions [M. Kllay, J. Chem. Phys. 141, 244113 (2014)], the size of the auxiliary basis of the domains and thus that of the three-center Coulomb integral lists can be reduced by an order of magnitude, which results in significant savings in computation time. The new approach is validated by extensive test calculations for energies and energy differences. Our benchmark calculations also demonstrate that the new method enables dRPA calculations for molecules with more than 1000 atoms and 10?000 basis functions on a single processor.
Zeroth-order design report for the next linear collider. Volume 2
Raubenheimer, T.O.
1996-05-01
This Zeroth-Order Design Report (ZDR) for the Next Linear Collider (NLC) has been completed as a feasibility study for a TeV-scale linear collider that incorporates a room-temperature accelerator powered by rf microwaves at 11.424 GHz--similar to that presently used in the SLC, but at four times the rf frequency. The purpose of this study is to examine the complete systems of such a collider, to understand how the parts fit together, and to make certain that every required piece has been included. The ``design`` presented here is not fully engineered in any sense, but to be assured that the NLC can be built, attention has been given to a number of critical components and issues that present special challenges. More engineering and development of a number of mechanical and electrical systems remain to be done, but the conclusion of this study is that indeed the NLC is technically feasible and can be expected to reach the performance levels required to perform research at the TeV energy scale. Volume II covers the following: collimation systems; IP switch and big bend; final focus; the interaction region; multiple bunch issues; control systems; instrumentation; machine protection systems; NLC reliability considerations; NLC conventional facilities. Also included are four appendices on the following topics: An RF power source upgrade to the NLC; a second interaction region for gamma-gamma, gamma-electron; ground motion: theory and measurement; and beam-based feedback: theory and implementation.
Non-linear macro evolution of a dc driven micro atmospheric glow discharge
Xu, S. F.; Zhong, X. X.
2015-10-15
We studied the macro evolution of the micro atmospheric glow discharge generated between a micro argon jet into ambient air and static water. The micro discharge behaves similarly to a complex ecosystem. Non-linear behaviors are found for the micro discharge when the water acts as a cathode, different from the discharge when water behaves as an anode. Groups of snapshots of the micro discharge formed at different discharge currents are captured by an intensified charge-coupled device with controlled exposure time, and each group consisted of 256 images taken in succession. Edge detection methods are used to identify the water surface and then the total brightness is defined by adding up the signal counts over the area of the micro discharge. Motions of the water surface at different discharge currents show that the water surface lowers increasingly rapidly when the water acts as a cathode. In contrast, the water surface lowers at a constant speed when the water behaves as an anode. The light curves are similar to logistic growth curves, suggesting that a self-inhibition process occurs in the micro discharge. Meanwhile, the total brightness increases linearly during the same time when the water acts as an anode. Discharge-water interactions cause the micro discharge to evolve. The charged particle bomb process is probably responsible for the different behaviors of the micro discharges when the water acts as cathode and anode.
Abrecht, David G.; Schwantes, Jon M.
2015-03-03
This paper extends the preliminary linear free energy correlations for radionuclide release performed by Schwantes, et al., following the Fukushima-Daiichi Nuclear Power Plant accident. Through evaluations of the molar fractionations of radionuclides deposited in the soil relative to modeled radionuclide inventories, we confirm the source of the radionuclides to be from active reactors rather than the spent fuel pool. Linear correlations of the form lnΧ=-α (ΔG_rxn^° (T_C ))/(RT_C )+β were obtained between the deposited concentration and the reduction potential of the fission product oxide species using multiple reduction schemes to calculate ΔG_rxn^° (T_C ). These models allowed an estimate of the upper bound for the reactor temperatures of T_C between 2130 K and 2220 K, providing insight into the limiting factors to vaporization and release of fission products during the reactor accident. Estimates of the release of medium-lived fission products 90Sr, 121mSn, 147Pm, 144Ce, 152Eu, 154Eu, 155Eu, 151Sm through atmospheric venting and releases during the first month following the accident were performed, and indicate large quantities of 90Sr and radioactive lanthanides were likely to remain in the damaged reactor cores.
Zeroth-order design report for the next linear collider. Volume 1
Raubenheimer, T.O.
1996-05-01
This Zeroth Order Design Report (ZDR) for the Next Linear Collider (NLC) has been completed as a feasibility study for a TeV-scale linear collider that incorporates a room-temperature accelerator powered by rf microwaves at 11.424 GHz--similar to that presently used in the SLC, but at four times the rf frequency. The purpose of this study is to examine the complete systems of such a collider, to understand how the parts fit together, and to make certain that every required piece has been included. The design presented here is not fully engineered in any sense, but to be assured that the NLC can be built, attention has been given to a number of critical components and issues that present special challenges. More engineering and development of a number of mechanical and electrical systems remain to be done, but the conclusion of this study is that indeed the NLC is technically feasible and can be expected to reach the performance levels required to perform research at the TeV energy scale. Volume one covers the following: the introduction; electron source; positron source; NLC damping rings; bunch compressors and prelinac; low-frequency linacs and compressors; main linacs; design and dynamics; and RF systems for main linacs.
Linear maps preserving maximal deviation and the Jordan structure of quantum systems
Hamhalter, Jan
2012-12-15
In the algebraic approach to quantum theory, a quantum observable is given by an element of a Jordan algebra and a state of the system is modelled by a normalized positive functional on the underlying algebra. Maximal deviation of a quantum observable is the largest statistical deviation one can obtain in a particular state of the system. The main result of the paper shows that each linear bijective transformation between JBW algebras preserving maximal deviations is formed by a Jordan isomorphism or a minus Jordan isomorphism perturbed by a linear functional multiple of an identity. It shows that only one numerical statistical characteristic has the power to determine the Jordan algebraic structure completely. As a consequence, we obtain that only very special maps can preserve the diameter of the spectra of elements. Nonlinear maps preserving the pseudometric given by maximal deviation are also described. The results generalize hitherto known theorems on preservers of maximal deviation in the case of self-adjoint parts of von Neumann algebras proved by Molnar.
Linear rheology and structure of molecular bottlebrushes with short side chains
López-Barrón, Carlos R. Brant, Patrick; Crowther, Donna J.; Eberle, Aaron P. R.
2015-05-15
We investigate the microstructure and linear viscoelasticity of model molecular bottlebrushes (BBs) using rheological and small-angle X-ray and neutron scattering measurements. Our polymers have short atactic polypropylene (aPP) side chains of molecular weight ranging from 119 g/mol to 259 g/mol and narrow molecular weight distribution (M{sub w}/M{sub n} 1.02–1.05). The side chain molecular weights are a small fraction of the entanglement molecular weight of the corresponding linear polymer (M{sub e,aPP}= 7.05 kg/mol), and as such, they are unentangled. The morphology of the aPP BBs is characterized as semiflexible thick chains with small side chain interdigitation. Their dynamic master curves, obtained by time-temperature superposition, reveal two sequential relaxation processes corresponding to the segmental relaxation and the relaxation of the BB backbone. Due to the short length of the side chains, their fast relaxation could not be distinguished from the glassy relaxation. The fractional free volume is an increasing function of the side chain length (N{sub SC}). Therefore, the glassy behavior of these polymers as well as their molecular friction and dynamic properties are influenced by their N{sub SC} values. The apparent flow activation energies are a decreasing function of N{sub SC}, and their values explain the differences in zero-shear viscosity measured at different temperatures.
Expanded studies of linear collider final focus systems at the Final Focus Test Beam
Tenenbaum, P.G.
1995-12-01
In order to meet their luminosity goals, linear colliders operating in the center-of-mass energy range from 3,50 to 1,500 GeV will need to deliver beams which are as small as a few Manometers tall, with x:y aspect ratios as large as 100. The Final Focus Test Beam (FFTB) is a prototype for the final focus demanded by these colliders: its purpose is to provide demagnification equivalent to those in the future linear collider, which corresponds to a focused spot size in the FFTB of 1.7 microns (horizontal) by 60 manometers (vertical). In order to achieve the desired spot sizes, the FFTB beam optics must be tuned to eliminate aberrations and other errors, and to ensure that the optics conform to the desired final conditions and the measured initial conditions of the beam. Using a combination of incoming-beam diagnostics. beam-based local diagnostics, and global tuning algorithms, the FFTB beam size has been reduced to a stable final size of 1.7 microns by 70 manometers. In addition, the chromatic properties of the FFTB have been studied using two techniques and found to be acceptable. Descriptions of the hardware and techniques used in these studies are presented, along with results and suggestions for future research.
Validity of the Taylor hypothesis for linear kinetic waves in the weakly collisional solar wind
Howes, G. G.; Klein, K. G.; TenBarge, J. M.
2014-07-10
The interpretation of single-point spacecraft measurements of solar wind turbulence is complicated by the fact that the measurements are made in a frame of reference in relative motion with respect to the turbulent plasma. The Taylor hypothesis—that temporal fluctuations measured by a stationary probe in a rapidly flowing fluid are dominated by the advection of spatial structures in the fluid rest frame—is often assumed to simplify the analysis. But measurements of turbulence in upcoming missions, such as Solar Probe Plus, threaten to violate the Taylor hypothesis, either due to slow flow of the plasma with respect to the spacecraft or to the dispersive nature of the plasma fluctuations at small scales. Assuming that the frequency of the turbulent fluctuations is characterized by the frequency of the linear waves supported by the plasma, we evaluate the validity of the Taylor hypothesis for the linear kinetic wave modes in the weakly collisional solar wind. The analysis predicts that a dissipation range of solar wind turbulence supported by whistler waves is likely to violate the Taylor hypothesis, while one supported by kinetic Alfvén waves is not.
Quantum chaos of an ion trapped in a linear ion trap
Berman, Gennady P. [Theoretical Division T-13, and CNLS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Theoretical Division T-13, and CNLS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); James, Daniel F. V. [Theoretical Division T-4, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Theoretical Division T-4, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Kamenev, Dimitri I. [Theoretical Division T-13, and CNLS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States) [Theoretical Division T-13, and CNLS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Nizhny Novgorod State University, Nizhny Novgorod, 603600, Russia (Russian Federation)
2000-06-01
We describe the transition to quantum chaos of an ion trapped in a linear ion trap and interacting with two laser fields. Under the conditions of adiabatic illumination of the upper level of the ion, and when the frequencies of the two laser beams are slightly different, the system is reduced to a quantum linear oscillator interacting with a monochromatic wave. The property of localization over the quantum resonance cells is proposed to exploit in order to facilitate the process of measurement of the probability distribution of an ion on the vibrational levels. In the regime of strong chaos the time-averaged values of the energy and dispersion of energy are computed and compared with the corresponding classical quantities for different values of the perturbation amplitude. In the exact resonance case, the classical analog of the system possesses an infinite inhomogeneous stochastic web. We analyze the quantum dynamics inside the inhomogeneous web. It is shown that the quantum system mimics on average the dynamics of the corresponding classical system. Formation of the quantum resonance cells is illustrated in the case of a finite detuning from the exact resonance, and under increasing of the wave amplitude. The parameters of the model and the initial conditions are close to the real physical situation which can be realized in the system of cold trapped ion perturbed by two lasers fields with close frequencies. (c) 2000 American Institute of Physics.
CALiPER Application Summary Report 21. Linear (T8) LED Lamps
2014-03-01
This report focuses on the bare lamp performance of 31 linear LED lamps intended as an alternative to T8 fluorescent lamps. Data obtained in accordance with IES LM-79-08 indicated that the mean efficacy is similar to that of fluorescent lamps, but that lumen output is often much lower. This presents a situation where something must change in order for energy savings and equivalent illumination levels to be achieved simultaneously. In this case, the luminous intensity distribution of all the tested lamps was directional or semi-directional, rather than omnidirectional. Also discussed in this report are several issues related to the electrical configuration of the lamps, such as the required socket types and power feed location. While no configuration is necessarily better, the multitude of options can make specifying and installing linear LED lamps more difficult, with the potential for safety issues. Similarly, the variety of color and power quality attributes adds a layer of complexity to the specification process. Many products offered good or excellent quality attributes, but some did not and thus could be perceived as inferior to fluorescent lamps in some installations.
Relativistic-Klystron two-beam accelerator as a power source for future linear colliders
Lidia, S. M.; Anderson, D. E.; Eylon, S.; Henestroza, E.; Vanecek, D. L.; Yu, S. S. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Houck, T. L.; Westenskow, G. A. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
1999-05-07
The technical challenge for making two-beam accelerators into realizable power sources for high-energy colliders lies in the creation of the drive beam and in its propagation over long distances through multiple extraction sections. This year we have been constructing a 1.2-kA, 1-MeV, induction gun for a prototype relativistic klystron two-beam accelerator (RK-TBA). The electron source will be a 8.9 cm diameter, thermionic, flat-surface cathode with a maximum shroud field stress of approximately 165 kV/cm. Additional design parameters for the injector include a pulse length of over 150-ns flat top (1% energy variation), and a normalized edge emittance of less than 300 pi-mm-mr. The prototype accelerator will be used to study, physics, engineering, and costing issues involved in the application of the RK-TBA concept to linear colliders. We have also been studying optimization parameters, such as frequency, for the application of the RK-TBA concept to multi-TeV linear colliders. As an rf power source the RK-TBA scales favorably up to frequencies around 35 GHz. An overview of this work with details of the design and performance of the prototype injector, beam line, and diagnostics will be presented.
Periodic permanent magnet development for linear collider X-band klystrons
Sprehn, D.; Caryotakis, G.; Jongewaard, E.; Phillips, R. [Stanford Linear Accelerator Center, Stanford University, Stanford, California 94309 (United States)
1999-05-07
The Stanford Linear Accelerator Center (SLAC) klystron group is currently designing, fabricating and testing 11.424 GHz klystrons with peak output powers from 50 to 75 MW at 1 to 2 {mu}s rf pulsewidths as part of an effort to realize components necessary for the construction of the Next Linear Collider (NLC). In order to eliminate the projected operational-year energy bill for klystron solenoids, Periodic Permanent Magnet (PPM) focusing has been employed on our latest X-band klystron designs. A PPM beam tester has operated at the same repetition rate, voltage and average beam power required for a 75-MW NLC klystron. Prototype 50 and 75-MW PPM klystrons were built and tested during 1996 and 1997 which operate from 50 to 70 MW at efficiencies greater than 55%. Construction and testing of 75-MW research klystrons will continue while the design and reliability is perfected. This paper will discuss the design of these PPM klystrons and the results of testing to date along with future plans for the development of a low-cost Design for Manufacture (DFM) 75-MW klystron and invitation for industry participation.
Relativistic-Klystron two-beam accelerator as a power source for future linear colliders
Lidia, S.M.; Anderson, D.E.; Eylon, S.; Henestroza, E.; Vanecek, D.L.; Yu, S.S. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Westenskow, G.A. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
1999-05-01
The technical challenge for making two-beam accelerators into realizable power sources for high-energy colliders lies in the creation of the drive beam and in its propagation over long distances through multiple extraction sections. This year we have been constructing a 1.2-kA, 1-MeV, induction gun for a prototype relativistic klystron two-beam accelerator (RK-TBA). The electron source will be a 8.9 cm diameter, thermionic, flat-surface cathode with a maximum shroud field stress of approximately 165 kV/cm. Additional design parameters for the injector include a pulse length of over 150-ns flat top (1{percent} energy variation), and a normalized edge emittance of less than 300 pi-mm-mr. The prototype accelerator will be used to study, physics, engineering, and costing issues involved in the application of the RK-TBA concept to linear colliders. We have also been studying optimization parameters, such as frequency, for the application of the RK-TBA concept to multi-TeV linear colliders. As an rf power source the RK-TBA scales favorably up to frequencies around 35 GHz. An overview of this work with details of the design and performance of the prototype injector, beam line, and diagnostics will be presented. {copyright} {ital 1999 American Institute of Physics.}
Periodic permanent magnet development for linear collider X-band klystrons
Sprehn, D.; Caryotakis, G.; Jongewaard, E.; Phillips, R. [Stanford Linear Accelerator Center, Stanford University, Stanford, California 94309 (United States)
1999-05-01
The Stanford Linear Accelerator Center (SLAC) klystron group is currently designing, fabricating and testing 11.424 GHz klystrons with peak output powers from 50 to 75 MW at 1 to 2 {mu}s rf pulsewidths as part of an effort to realize components necessary for the construction of the Next Linear Collider (NLC). In order to eliminate the projected operational-year energy bill for klystron solenoids, Periodic Permanent Magnet (PPM) focusing has been employed on our latest X-band klystron designs. A PPM beam tester has operated at the same repetition rate, voltage and average beam power required for a 75-MW NLC klystron. Prototype 50 and 75-MW PPM klystrons were built and tested during 1996 and 1997 which operate from 50 to 70 MW at efficiencies greater than 55{percent}. Construction and testing of 75-MW research klystrons will continue while the design and reliability is perfected. This paper will discuss the design of these PPM klystrons and the results of testing to date along with future plans for the development of a low-cost Design for Manufacture (DFM) 75-MW klystron and invitation for industry participation. {copyright} {ital 1999 American Institute of Physics.}
Relativistic-klystron two-beam accelerator as a power source for future linear colliders
Anderson, D E; Eylon, S; Henestroza, E; Houck, T L; Lidia, M; Vanecek, D L; Westenskow, G A; Yu, S S
1998-10-05
The technical challenge for making two-beam accelerators into realizable power sources for high-energy colliders lies in the creation of the drive beam and in its propagation over long distances through multiple extraction sections. This year we have been constructing a 1.2&A, l-MeV, induction gun for a prototype relativistic klystron two-beam accelerator (RK-TBA). The electron source will be a 8.9 cm diameter, thermionic, flat-surface cathode with a maximum shroud field stress of approximately 165 kV/cm. Additional design parameters for the injector include a pulse length of over 150-ns flat top (1% energy variation), and a normalized edge emittance of less than 300 pi-mm-n-n. The prototype accelerator will be used to study physics, engineering, and costing issues involved in the application of the RK-TBA concept to linear colliders. We have also been studying optimization parameters, such as frequency, for the application of the RK-TBA concept to multi-TeV linear colliders. As an rf power source the RK-TBA scales favorably up to frequencies around 35 GHz. An overview of this work with details of the design and performance of the prototype injector, beam line, and diagnostics will be presented.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Ye, Tianyu; Liu, Han -Chun; Wang, Zhuo; Wegscheider, W.; Mani, Ramesh G.
2015-10-09
A comparative study of the radiation-induced magnetoresistance oscillations in the high mobility GaAs/AlGaAs heterostructure two dimensional electron system (2DES) under linearly- and circularly- polarized microwave excitation indicates a profound difference in the response observed upon rotating the microwave launcher for the two cases, although circularly polarized microwave radiation induced magnetoresistance oscillations observed at low magnetic fields are similar to the oscillations observed with linearly polarized radiation. For the linearly polarized radiation, the magnetoresistive response is a strong sinusoidal function of the launcher rotation (or linear polarization) angle, θ. As a result, for circularly polarized radiation, the oscillatory magnetoresistive response ismore » hardly sensitive to θ.« less
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Hager, Robert; Yoon, E. S.; Ku, S.; D'Azevedo, E. F.; Worley, P. H.; Chang, C. S.
2016-04-04
Fusion edge plasmas can be far from thermal equilibrium and require the use of a non-linear collision operator for accurate numerical simulations. The non-linear single-species Fokker–Planck–Landau collision operator developed by Yoon and Chang (2014) [9] is generalized to include multiple particle species. Moreover, the finite volume discretization used in this work naturally yields exact conservation of mass, momentum, and energy. The implementation of this new non-linear Fokker–Planck–Landau operator in the gyrokinetic particle-in-cell codes XGC1 and XGCa is described and results of a verification study are discussed. Finally, the numerical techniques that make our non-linear collision operator viable on high-performance computingmore » systems are described, including specialized load balancing algorithms and nested OpenMP parallelization. As a result, the collision operator's good weak and strong scaling behavior are shown.« less
Shang, Yu; Yu, Guoqiang
2014-09-29
Conventional semi-infinite analytical solutions of correlation diffusion equation may lead to errors when calculating blood flow index (BFI) from diffuse correlation spectroscopy (DCS) measurements in tissues with irregular geometries. Very recently, we created an algorithm integrating a Nth-order linear model of autocorrelation function with the Monte Carlo simulation of photon migrations in homogenous tissues with arbitrary geometries for extraction of BFI (i.e., αD{sub B}). The purpose of this study is to extend the capability of the Nth-order linear algorithm for extracting BFI in heterogeneous tissues with arbitrary geometries. The previous linear algorithm was modified to extract BFIs in different types of tissues simultaneously through utilizing DCS data at multiple source-detector separations. We compared the proposed linear algorithm with the semi-infinite homogenous solution in a computer model of adult head with heterogeneous tissue layers of scalp, skull, cerebrospinal fluid, and brain. To test the capability of the linear algorithm for extracting relative changes of cerebral blood flow (rCBF) in deep brain, we assigned ten levels of αD{sub B} in the brain layer with a step decrement of 10% while maintaining αD{sub B} values constant in other layers. Simulation results demonstrate the accuracy (errors < 3%) of high-order (N ≥ 5) linear algorithm in extracting BFIs in different tissue layers and rCBF in deep brain. By contrast, the semi-infinite homogenous solution resulted in substantial errors in rCBF (34.5% ≤ errors ≤ 60.2%) and BFIs in different layers. The Nth-order linear model simplifies data analysis, thus allowing for online data processing and displaying. Future study will test this linear algorithm in heterogeneous tissues with different levels of blood flow variations and noises.
Cosmic bubble and domain wall instabilities I: parametric amplification of linear fluctuations
Braden, Jonathan; Bond, J. Richard; Mersini-Houghton, Laura
2015-03-03
This is the first paper in a series where we study collisions of nucleated bubbles taking into account the effects of small initial (quantum) fluctuations in a fully 3+1-dimensional setting. In this paper, we consider the evolution of linear fluctuations around highly symmetric though inhomogeneous backgrounds. In particular, we demonstrate that a large degree of asymmetry develops over time from tiny initial fluctuations superposed upon planar and SO(2,1) symmetric backgrounds. These fluctuations are inevitable consequences of zero-point vacuum oscillations, so excluding them by enforcing a high degree of spatial symmetry is inconsistent in a quantum treatment. To simplify the analysis we consider the limit of two colliding planar walls, with mode functions for the fluctuations characterized by the wavenumber transverse to the collision direction and a longitudinal shape along the collision direction x, which we solve for. In the linear regime, the fluctuations obey a linear wave equation with a time- and space-dependent mass m{sub eff}(x,t). In situations where the walls collide multiple times, m{sub eff} oscillates in time. We use Floquet theory to study the evolution of the fluctuations and generalize the calculations familiar from the preheating literature to the case with many coupled degrees of freedom. The inhomogeneous case has bands of unstable transverse wavenumbers k{sub ⊥} whose corresponding mode functions grow exponentially. By examining the detailed spatial structure of the mode functions in x, we identify both broad and narrow parametric resonance generalizations of the homogeneous m{sub eff}(t) case of preheating. The unstable k{sub ⊥} modes are longitudinally localized, yet can be described as quasiparticles in the Bogoliubov sense. We define an effective occupation number and show they are created in bursts for the case of well-defined collisions in the background. The transverse-longitudinal coupling accompanying nonlinearity radically
The pulsed linear induction motor concept for high-speed trains
Turman, B.N.; Marder, B.M.; Rohwein, G.J.; Aeschliman, D.P.; Kelley, J.B.; Cowan, M.; Zimmerman, R.M.
1995-06-01
The SERAPBIM (SEgmented RAil PHased Induction Motor) concept is a linear induction motor concept which uses rapidly-pulsed magnetic fields and a segmented reaction rail, as opposed to low-frequency fields and continuous reaction rails found in conventional linear induction motors. These improvements give a high-traction, compact, and efficient linear motor that has potential for advanced high speed rail propulsion. In the SERAPBIM concept, coils on the vehicle push against a segmented aluminum rail, which is mounted on the road bed. Current is pulsed as the coils cross an edge of the segmented rail, inducing surface currents which repel the coil. The coils must be pulsed in synchronization with the movement by reaction rail segments. This is provided by a sense-and-fire circuit that controls the pulsing of the power modulators. Experiments were conducted to demonstrate the feasibility of the pulsed induction motor and to collect data that could be used for scaling calculations. A 14.4 kg aluminum plate was accelerated down a 4 m track to speeds of over 15 m/sec with peak thrust up to 18 kN per coilset. For a trainset capable of 200 mph speed, the SERAPHIM concept design is based on coils which are each capable of producing up to 3.5 kN thrust, and 30 coil pairs are mounted on each power car. Two power cars, one at each end of the train, provide 6 MW from two gas turbine prime power units. The thrust is about 210.000 N and is essentially constant up to 200 km/hr since wheel slippage does not limit thrust as with conventional wheeled propulsion. A key component of the SERAPHIM concept is the use of passive wheel-on-rah support for the high speed vehicle. Standard steel wheels are capable of handling over 200 mph. The SERAPHIM cost is comparable to that for steel-wheel high-speed rail, and about 10% to 25% of the projected costs for a comparable Maglev system.
Off-resonance energy absorption in a linear Paul trap due to mass selective resonant quenching
Sivarajah, I.; Goodman, D. S.; Wells, J. E.; Smith, W. W.; Narducci, F. A.
2013-11-15
Linear Paul traps (LPT) are used in many experimental studies such as mass spectrometry, atom-ion collisions, and ion-molecule reactions. Mass selective resonant quenching (MSRQ) is implemented in LPT either to identify a charged particle's mass or to remove unwanted ions from a controlled experimental environment. In the latter case, MSRQ can introduce undesired heating to co-trapped ions of different mass, whose secular motion is off resonance with the quenching ac field, which we call off-resonance energy absorption (OREA). We present simulations and experimental evidence that show that the OREA increases exponentially with the number of ions loaded into the trap and with the amplitude of the off-resonance external ac field.
Acoustically determined linear piezoelectric response of lithium niobate up to 1100 V
Patel, N.; Branch, D. W.; Cular, S.; Schamiloglu, E.
2014-04-21
We present a method to measure high voltages using the piezoelectric crystal lithium niobate without using voltage dividers. A 36° Y-X cut lithium niobate crystal was coupled to two acoustic transducers, where direct current voltages were applied from 128–1100 V. The time-of-flight through the crystal was determined to be linearly dependent on the applied voltage. A model was developed to predict the time-delay in response to the applied voltage. The results show a sensitivity of 17 fs/V with a measurement error of 1 fs/V was achievable using this method. The sensitivity of this method can be increased by measuring the acoustic wave after multiple passes through the crystal. This method has many advantages over traditional techniques such as: favorable scalability for larger voltages, ease of use, cost effectiveness, and compactness.
Multiple-Input Multiple-Output (MIMO) Linear Systems Extreme Inputs/Outputs
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Smallwood, David O.
2007-01-01
A linear structure is excited at multiple points with a stationary normal random process. The response of the structure is measured at multiple outputs. If the autospectral densities of the inputs are specified, the phase relationships between the inputs are derived that will minimize or maximize the trace of the autospectral density matrix of the outputs. If the autospectral densities of the outputs are specified, the phase relationships between the outputs that will minimize or maximize the trace of the input autospectral density matrix are derived. It is shown that other phase relationships and ordinary coherence less than one willmore » result in a trace intermediate between these extremes. Least favorable response and some classes of critical response are special cases of the development. It is shown that the derivation for stationary random waveforms can also be applied to nonstationary random, transients, and deterministic waveforms.« less
Linear mechanism of surface gravity wave generation in horizontally sheared flow
Kalashnik, M. V.
2008-01-15
An analysis is presented of a linear mechanism of surface gravity wave generation in a horizontally sheared flow in a fluid layer with free boundary. A free-surface flow of this type is found to be algebraically unstable. The development of instability leads to the formation of surface gravity waves whose amplitude grows with time according to a power law. Flow stability is analyzed by using a nonmodal approach in which the behavior of a spatial Fourier harmonic of a disturbance is considered in a semi-Lagrangian frame of reference moving with the flow. Shear-flow disturbances are divided into two classes (wave and vortex disturbances) depending on the value of potential vorticity. It is shown that vortex disturbances decay with time while the energy of wave disturbances increases indefinitely. Transformation of vortex disturbances into wave ones under strong shear is described.
Time-of-flight secondary ion mass spectrometry of deuterated linear poly(dimethylsiloxane)
Zhang, X.K.; Stuart, J.O.; Clarson, S.J. ); Sabata, A. ); Beaucage, G. )
1994-08-29
Mass spectrometry (MS) has previously proved to be very valuable for characterizing the thermal decomposition of poly-(dimethylsiloxane) (PDMS) via pyrolysis-MS. Secondary ion mass spectrometry (SIMS) has also been applied to identify the various fragments characteristic of PDMS and thus give fingerprint'' spectra for identification purposes. This paper describes the characterization of deuterated linear PDMS -[(CD[sub 3])[sub 2]SiO][sub n]- using time-of-flight secondary ion mass spectrometry. The work is part of a program investigating the conformations and interactions of deuterated siloxanes in isotopic blends -[(CD[sub 3])[sub 2]SiO][sub n]-/-[CH[sub 3][sub 2]SiO][sub n]- using small-angle neutron scattering. It is therefore clearly important to demonstrate that no deuterium/hydrogen exchanges occurred during the synthetic methodology used.
Structure/Function Studies of Proteins Using Linear Scaling Quantum Mechanical Methodologies
Merz, K. M.
2004-07-19
We developed a linear-scaling semiempirical quantum mechanical (QM) program (DivCon). Using DivCon we can now routinely carry out calculations at the fully QM level on systems containing up to about 15 thousand atoms. We also implemented a Poisson-Boltzmann (PM) method into DivCon in order to compute solvation free energies and electrostatic properties of macromolecules in solution. This new suite of programs has allowed us to bring the power of quantum mechanics to bear on important biological problems associated with protein folding, drug design and enzyme catalysis. Hence, we have garnered insights into biological systems that have been heretofore impossible to obtain using classical simulation techniques.
Whistler waves produced by a modulated spiraling electron beam: Linear approach
Krafft, C.; Volokitin, A.; Matthieussent, G.
1996-03-01
The theory of whistler wave interaction with a modulated electron beam injected obliquely to the magnetic field in an unbounded space plasma is considered. The study of the energy transfer between the spiraling beam and the whistler wave is done in the case of sheared whistlers, when the parallel wave number is very small compared to the perpendicular one. In the linear regime, structures of potentials and electromagnetic fields in the beam vicinity and in the wave zone are obtained analytically: Simple expressions for field components are provided for {hacek C}erenkov and Doppler resonances, in double and single pole cases. Emitted power is calculated as a function of beam parameters. {copyright} {ital 1996 American Institute of Physics.}