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How to Take Better Photographs: Control Quality by Controlling the Camera

Description: In this Tech Talk presentation, the authors demonstrate simple ways to improve a photograph by making use of camera controls and by considering location, lighting, and composition. The authors will introduce basic information about using manual camera settings to control aperture, shutter speed, and ISO, and the authors will discuss specific "shooting" situations such as portraits, group photos, and events.
Date: July 27, 2011
Creator: Jones, Jerrell & Hall, Nathan
Partner: UNT Libraries

Latest results from the SEMATECH Berkeley extreme ultraviolet microfield exposure tool

Description: Microfield exposure tools (METs) continue to play a dominant role in the development of extreme ultraviolet (EUV) resists. One of these tools is the 0.3 numerical aperture SEMATECH Berkeley MET operating as a resist and mask test center. Here they present an update on the tool summarizing some of the latest test and characterization results. they provide an update on the long-term aberration stability of the tool and present line-space imaging in chemically amplified photoresist down to the 20-nm half-pitch level. Although resist development has shown substantial progress in the area of resolution, line-edge-roughness (LER) remains a significant concern. Here we present a summary of recent LER performance results and consider the effect of mask contributors to the LER observed from the SEMATECH Berkeley microfield tool.
Date: September 2, 2008
Creator: Naulleau, Patrick; Anderson, Christopher N.; Chiu, Jerrin; Dean, Kim; Denham, Paul; George, Simi et al.
Partner: UNT Libraries Government Documents Department

Comparison of Tevatron C0 and F0 Lambertson beam impedance

Description: Both the longitudinal and transverse beam impedance measurements for the Tevatron C0 and F0 lambertsons are presented. The C0 lambertsons were designed for circulating beam to travel through the 1 inch high by 6 inch wide field region. In the F0 lambertsons, circulating beam passes through the 2.5 inch high by 4 in ch wide field free region. The more recently designed F0 lambertsons have significantly less impedance than the older C0 lambertsons. Transverse impedance scales as one over the diameter of the aperture cubed. The three C0 style lambertsons were recently removed from the Tevatron. Four of the F0 lambertsons remain. Nine of the F0 style lambertsons are in the Main Injector and three more are required for Numi.
Date: April 11, 2003
Creator: Fellenz, James L Crisp and Brian
Partner: UNT Libraries Government Documents Department

Aperture limitations for 2nd generation Nb3Sn LHC IR quadrupoles

Description: One of the straightforward ways towards the higher luminosity in the LHC is a replacement of the present 70-mm NbTi quadrupoles with Nb{sub 3}Sn quadrupoles which would provide the same field gradient but in a larger aperture. Conceptual designs of such quadrupoles with 90 mm aperture have been developed and studied. This paper discusses the possibilities and limitations of increasing the aperture of Nb{sub 3}Sn low-beta quadrupoles for a LHC luminosity upgrade up to 110 mm.
Date: June 2, 2003
Creator: Zlobin, Alexander V.; Kashikhin, Vadim V. & Strait, James B.
Partner: UNT Libraries Government Documents Department

Coupling Through Tortuous Path Narrow Slot Apertures into Complex Cavitivies

Description: A hybrid FEM/MoM model has been implemented to compute the coupling of fields into a cavity through narrow slot apertures having depth. The model utilizes the slot model of Warne and Chen [23]-[29] which takes into account the depth of the slot, wall losses, and inhomogeneous dielectrics in the slot region. The cavity interior is modeled with the mixed-order, covariant-projection hexahedral elements of Crowley [32]. Results are given showing the accuracy and generality of the method for modeling geometrically complex slot-cavity combinations.
Date: July 26, 1999
Creator: Jedlicka, Russell P.; Castillo, Steven P. & Warne, Larry K.
Partner: UNT Libraries Government Documents Department

PDII- Additional discussion of the dynamic aperture

Description: This note is in the nature of an addition to the dynamic aperture calculations found in the report on the Proton Driver, FERMILAB-TM-2169. A extensive discussion of the Proton Driver lattice, as well as the nomenclature used to describe it can be found in TM-2169. Basically the proposed lattice is a racetrack design with the two arcs joined by two long straight sections. The straight sections are dispersion free. Tracking studies were undertaken with the objective of computing the dynamic aperture for the lattice and some of the results have been incorporated into TM-2169. This note is a more extensive report of those calculations.
Date: July 23, 2002
Creator: Gelfand, Norman M.
Partner: UNT Libraries Government Documents Department

Lithographic characterization of low-order aberrations in a 0.3-NAEUV microfield exposure tool

Description: Although tremendous progress has been made in the crucial area of fabrication of extreme ultraviolet (EUV) projection optics, the realization diffraction-limited high numerical aperture (NA) optics (above 0.2 NA) remains a concern. The highest NA EUV optics available to date are the 0.3-NA Microfield Exposure Tool (MET) optics used in an experimental exposure station at Lawrence Berkeley National Laboratory [1] and commercial METs [2] at Intel and SEMATECH-North. Even though these optics have been interferometrically demonstrated to achieve diffraction-limited wavefront quality, the question remains as to whether or not such performance levels can be maintained after installation of the optics into the exposure tool. Printing-based quantitative aberration measurements provide a convenient mechanism for the characterization of the optic wavefront error in the actual lithography tool. We present the lithographic measurement of low-order aberrations in the Berkeley MET tool, including a quantitative measurement of astigmatism and spherical error and a qualitative measurement of coma. The lithographic results are directly compared to interferometry results obtained from the same optic. Measurements of the Berkeley MET indicate either an alignment drift or errors in the interferometry on the order of 0.5 to 1 nm.
Date: March 1, 2006
Creator: Naulleau, Patrick; Cain, Jason; Dean, Kim & Goldberg, Kenneth A.
Partner: UNT Libraries Government Documents Department

Techniques for Identifying and Measuring High Order Modes in RF Cavities

Description: We report on a number of techniques which can be used to unravel the higher-order-mode spectrum of an RF cavity. Most of these techniques involve the application of basic symmetry principles and require for their application only that the cavity exhibit some basic symmetry, possibly broken by the presence of couplers, apertures, etc., which permits a classification of these modes in terms of some property characterized by that symmetry, e.g., multipolarity for a cavity which is basically a figure of revolution. Several examples of the application of these techniques are given.
Date: May 1, 1997
Creator: Goldberg, D.A. & Rimmer, R.A.
Partner: UNT Libraries Government Documents Department

Orbit, optics and chromaticity correction for PS2 negative momentum compaction lattices

Description: The effect of magnet misalignments in the beam orbit and linear optics functions are reviewed and correction schemes are applied to the negative momentum compaction lattice of PS2. Chromaticity correction schemes are also proposed and tested with respect to off-momentum optics properties. The impact of the correction schemes in the dynamic aperture of the lattice is finally evaluated.
Date: May 4, 2009
Creator: Papaphilippou,Y.; Barranco, J.; Bartmann, W.; Benedikt, M.; Carli, C.; de Maria, R. et al.
Partner: UNT Libraries Government Documents Department

Precision Pointing System Development

Description: The development of precision pointing systems has been underway in Sandia's Electronic Systems Center for over thirty years. Important areas of emphasis are synthetic aperture radars and optical reconnaissance systems. Most applications are in the aerospace arena, with host vehicles including rockets, satellites, and manned and unmanned aircraft. Systems have been used on defense-related missions throughout the world. Presently in development are pointing systems with accuracy goals in the nanoradian regime. Future activity will include efforts to dramatically reduce system size and weight through measures such as the incorporation of advanced materials and MEMS inertial sensors.
Date: March 1, 2003
Creator: Bugos, Robert M.
Partner: UNT Libraries Government Documents Department

Spatial filter issues

Description: Experiments and calculations indicate that the threshold pressure in spatial filters for distortion of a transmitted pulse scales approximately as I{sup O.2} and (F{number_sign}){sup 2} over the intensity range from 10{sup 14} to 2xlO{sup 15} W/CM{sup 2} . We also demonstrated an interferometric diagnostic that will be used to measure the scaling relationships governing pinhole closure in spatial filters.
Date: December 9, 1996
Creator: Murray, J.E.; Estabrook, K.G.; Milam, D.; Sell, W.D.; Van Wonterghem, R.M.; Feil, M.D. et al.
Partner: UNT Libraries Government Documents Department

VARIABLE MOMENTUM COMPACTION LATTICE STUDIES.

Description: The VUV storage ring at the National Synchrotron Light Source was used to study the impact of changes in the momentum compaction factors over a large range from positive to negative values. Changes in bunch length and synchrotron tune were measured versus current and RF parameters for these different lattices. By controlling both the first and second-order momentum compaction factors, a lattice was developed in which a pair of alpha buckets was created within the energy aperture of the vacuum chamber and beam was stored simultaneously in both buckets.
Date: March 29, 1999
Creator: KRAMER,S. & MURPHY,J.B.
Partner: UNT Libraries Government Documents Department

Composite Resonator Surface Emitting Lasers

Description: The authors have developed electrically-injected coupled-resonator vertical-cavity lasers and have studied their novel properties. These monolithically grown coupled-cavity structures have been fabricated with either one active and one passive cavity or with two active cavities. All devices use a selectively oxidized current aperture in the lower cavity, while a proton implant was used in the active-active structures to confine current in the top active cavity. They have demonstrated optical modulation from active-passive devices where the modulation arises from dynamic changes in the coupling between the active and passive cavities. The laser intensity can be modulated by either forward or reverse biasing the passive cavity. They have also observed Q-switched pulses from active-passive devices with pulses as short as 150 ps. A rate equation approach is used to model the Q-switched operation yielding good agreement between the experimental and theoretical pulseshape. They have designed and demonstrated the operation of active-active devices which la.se simultaneously at both longitudinal cavity resonances. Extremely large bistable regions have also been observed in the light-current curves for active-active coupled resonator devices. This bistability can be used for high contrast switching with contrast ratios as high as 100:1. Coupled-resonator vertical-cavity lasers have shown enhanced mode selectivity which has allowed devices to lase with fundamental-mode output powers as high as 5.2 mW.
Date: May 1, 2000
Creator: FISCHER,ARTHUR J.; CHOQUETTE,KENT D.; CHOW,WENG W.; ALLERMAN,ANDREW A. & GEIB,KENT M.
Partner: UNT Libraries Government Documents Department

A calculation of the dynamic aperture of the LHC

Description: The dynamic aperture for version 5.1, with a 300{mu}r crossing angle at IP1 and IP5, of the Large Hadron Collider (LHC) lattice has been estimated using the tracking code TEVLAT. The dynamic aperture calculated here is due to the magnetic field errors in the high gradient quadrupoles (MQX) in the two low-{beta} interaction regions at IR1 and IR5. No errors were assigned to the magnets in the arc regions of the lattice, nor were beam-beam effects incorporated. The dynamic aperture is expressed in terms of the {sigma} of the beam corresponding to the beam emittance of 3.75mm mr. With only short term tracking, the combined effect of the multipoles and the crossing angle is to yield an average (over multipole coefficients generated with 100 different seeds) dynamic aperture of {approx} 11.7 {plus_minus} 1.2{sigma}.
Date: April 23, 1999
Creator: Gelfand, Norman M.
Partner: UNT Libraries Government Documents Department

VARIABLE MOMENTUM COMPACTION LATTICE STUDIES.

Description: The VUV storage ring at the National Synchrotron Light Source was used to study the impact of changes in the momentum compaction factors over a large range from positive to negative values. Changes in bunch length and synchrotron tune were measured versus current and RF parameters for these different lattices. By controlling both the first and second-order momentum compaction factors, a lattice was developed in which a pair of alpha buckets was created within the energy aperture of the vacuum chamber and beam was stored simultaneously in both buckets.
Date: March 29, 1999
Creator: KRAMER,S. & MURPHY,J.B.
Partner: UNT Libraries Government Documents Department

Conceptual design study of Nb3Sn low-beta quadrupoles for 2nd generation LHC IRs

Description: Conceptual designs of 90-mm aperture high-gradient quadrupoles based on the Nb{sub 3}Sn superconductor, are being developed at Fermilab for possible 2nd generation IRs with the similar optics as in the current low-beta insertions. Magnet designs and results of magnetic, mechanical, thermal and quench protection analysis for these magnets are presented and discussed.
Date: October 22, 2002
Creator: al., Alexander V Zlobin et
Partner: UNT Libraries Government Documents Department

Dynamic aperture study for the NLC main damping rings

Description: A sufficiently large acceptance is critical for the NLC Main Damping Rings (MDR) as the high power carried by the beams demands very high injection efficiency. Chromatic sextupoles and wiggler insertions (needed for rapid damping) are substantial sources of nonlinearities limiting the dynamic aperture. We report on the techniques we are using for analysis of single-particle beam dynamics in the presence of wiggler fields with significant nonlinear components. We demonstrate that our approach gives results in good agreement with experimental data when applied to the BL11 wiggler in SPEAR2, and discuss the present status of studies for the NLC MDR.
Date: July 5, 2004
Creator: Wolski, Andrzej; Venturini, Marco & Marks, Steve
Partner: UNT Libraries Government Documents Department

Spatially Interpolated Nonlinear Anodization in Synthetic Aperture Radar Imagery

Description: Spatially Interpolated Nonlinear Anodization in Synthetic Aperture Original formulation of spatially variant anodization for complex synthetic aperture radar (SAR) imagery oversampled at twice the Nyquist rate (2.OX). Here we report a spatially interpolating, noninteger-oversampled SVA sidelobe. The pixel's apparent IPR location is assessed by comparing its value to the sum of its value plus weighted comparable for exact interpolation. However, exact interpolation implies an ideal sine interpolator3 and large components may not be necessary. Note that P is the summation of IPR diagonal values. The value of a sine IPR on the diagonals is a sine-squared; values much less than cardinal direction (m, n) values. This implies that cardinal direction interpolation requires higher precision than diagonal interpolation. Consequently, we employed a smaller set. The spatially interpolated SVA used an 8-point/4-point sine interpolator described above. Table 1 shows the Table 1 results show a two-times speed-up using the 1.3x oversampled and spatially interpolated SVA over the Figure 1d. Detected results of 1.3x oversampled sine interpolated spatially variant
Date: June 29, 1999
Creator: Eichel, Paul H.; Jakowatz, Jr., Charles V. & Yocky, David A.
Partner: UNT Libraries Government Documents Department

Effect of Wiggler insertions on the single-particle dynamics of the NLC main damping rings

Description: As they are expected to occupy a large portion of the lattice, wiggler insert ions will introduce significant linear and nonlinear perturbations to the single-particle dynamics in the NLC Main Damping Rings (MDR). The nonlinearities are of particular concern as a sufficiently large Dynamic Aperture (DA) is required for high injection efficiency. The main content of this report is a study of the wigglers impact on the DA of the NLC-MDR latest lattice design. The particle dynamics is modeled by transfer maps calculated by integration through the wiggler fields. For field representation we employed a 3D multipole expansion derived from the field data that were obtained with the aid of a magnet design code. Additional contents of this paper include an investigation of a simplified model of wiggler consisting of a sequence of standard magnet elements (where thin octupoles are used to represent the dominant nonlinearities) and the suggestion of a possible correction scheme to compensate the wiggler nonlinearities.
Date: July 30, 2003
Creator: Venturini, Marco
Partner: UNT Libraries Government Documents Department

Multiphase flow in complex fracture apertures under a wide range of flow conditions

Description: The primary purpose of this project is to use a combination of computer modeling and laboratory experiments to obtain a better understanding of multiphase flow in geometrically complex fracture apertures under a wide range of flow conditions. Because traditional grid-based numeral methods perform poorly for multiphase flows with complex dynamic interfaces due to problems such as artificial interface broadening and grid entanglement, the modeling component of the program relies on particle based methods. In particle based models, the fluid-fluid interfaces move as the particles representing the fluids move--there is no need for explicit interface tracking, and no artificial front broadening. Because, different model approaches have characteristic strengths and weaknesses three different classes of particle-based models (lattice Boltzmann, dissipative particle dynamics and smoothed particle hydrodynamics) will be employed in this program. This will allow us to achieve our objective of simulating multiphase flow under a wide range of flow conditions for a wide range of fluid properties.
Date: June 1, 2003
Creator: Meakin, Paul; McCrerry, Glenn E. & McCligot, Donald
Partner: UNT Libraries Government Documents Department

Scalar wave diffraction from a circular aperture

Description: The scalar wave theory is used to evaluate the expected diffraction patterns from a circular aperture. The standard far-field Kirchhoff approximation is compared to the exact result expressed in terms of oblate spheroidal harmonics. Deviations from an expanding spherical wave are calculated for circular aperture radius and the incident beam wavelength using suggested values for a recently proposed point diffractin interferometer. The Kirchhoff approximation is increasingly reliable in the far-field limit as the aperture radius is increased, although significant errors in amplitude and phase persist.
Date: January 25, 1995
Creator: Cerjan, C.
Partner: UNT Libraries Government Documents Department

Tracking of three variants of transition-free lattices for a proton driver

Description: Transition-free lattices are favored as possible realization of proton drivers. Several variants have been proposed, some of which have considerably different behavior. One of the main quantities used to characterize this behavior is the short term dynamic aperture (DA). In this note we study three different variants of such lattices, and show that the differences in DA among the lattices essentially disappear as soon as magnet multipole errors are included in the simulation. The tracking results can be understood in terms of the normal form based amplitude dependent tune shift and resonance strength coefficients.
Date: October 14, 2002
Creator: Johnstone, Bela Erdelyi and Carol
Partner: UNT Libraries Government Documents Department