790 Matching Results

Search Results

Advanced search parameters have been applied.

Anti-B-B Mixing Constrains Topcolor-Assisted Technicolor

Description: We argue that extended technicolor augmented with topcolor requires that all mixing between the third and the first two quark generations resides in the mixing matrix of left-handed down quarks. Then, the anti-B_d--B_d mixing that occurs in topcolor models constrains the coloron and Z' boson masses to be greater than about 5 TeV. This implies fine tuning of the topcolor couplings to better than 1percent.
Date: December 6, 2000
Creator: Burdman, Gustavo; Lane, Kenneth & Rador, Tonguc
Partner: UNT Libraries Government Documents Department

The Supersymmetric Fat Higgs

Description: Supersymmetric models have traditionally been assumed to be perturbative up to high scales due to the requirement of calculable unification. In this note I review the recently proposed `Fat Higgs' model which relaxes the requirement of perturbativity. In this framework, an NMSSM-like trilinear coupling becomes strong at some intermediate scale. The NMSSM Higgses are meson composites of an asymptotically-free gauge theory. This allows us to raise the mass of the Higgs, thus alleviating the MSSM of its fine tuning problem. Despite the strong coupling at an intermediate scale, the UV completion allows us to maintain gauge coupling unification.
Date: October 27, 2004
Creator: Harnik, Roni
Partner: UNT Libraries Government Documents Department

Corner rounding in EUV photoresist: tuning through molecular weight, PAG size, and development time

Description: In this paper, the corner rounding bias of a commercially available extreme ultraviolet photoresist is monitored as molecular weight, photoacid generator (PAG) size, and development time are varied. These experiments show that PAG size influences corner biasing while molecular weight and development time do not. Large PAGs are shown to exhibit less corner biasing, and in some cases, lower corner rounding, than small PAGs. In addition, heavier resist polymers are shown to exhibit less corner rounding than lighter ones.
Date: December 31, 2009
Creator: Anderson, Christopher; Daggett, Joe & Naulleau, Patrick
Partner: UNT Libraries Government Documents Department

Collecting EUV mask images through focus by wavelength tuning

Description: Using an extreme-ultraviolet (EUV) microscope to produce high-quality images of EUV reticles, we have developed a new wavelength tuning method to acquire through-focus data series with a higher level of stability and repeatability than was previously possible. We utilize the chromatic focal-length dependence of a diffractive Fresnel zoneplate objective lens, and while holding the mask sample mechanically still, we tune the wavelength through a narrow range, in small steps. In this paper, we demonstrate the method and discuss the relative advantages that this data collection technique affords.
Date: February 23, 2009
Creator: Goldberg, Kenneth A.; Mochi, Iacopo & Huh, Sungmin
Partner: UNT Libraries Government Documents Department

Modern Api Design and Physical Computing Techniques in Just Intonation Performance Practice

Description: approached previously by both Harry Partch and Ben Johnston, and proposes the decoupling of interface and sound production as a way forward. The design and implementation of a software instrument and a hardware prototype are described, both using a simple API for variable tuning instruments. The hardware prototype uses physical computing techniques to control the tuning of a string with a servo motor, while the software instrument exists entirely in a web browser. Finally, potential algorithms for clients of the API are presented, and the effectiveness of the hardware prototype is evaluated by measuring its pitch accuracy.
Date: May 2013
Creator: Sonnabaum, Mark
Partner: UNT Libraries

Design Calculations For NIF Convergent Ablator Experiments

Description: The NIF convergent ablation tuning effort is underway. In the early experiments, we have discovered that the design code simulations over-predict the capsule implosion velocity and shock flash rhor, but under-predict the hohlraum x-ray flux measurements. The apparent inconsistency between the x-ray flux and radiography data implies that there are important unexplained aspects of the hohlraum and/or capsule behavior.
Date: October 25, 2011
Creator: Olson, R E; Hicks, D G; Meezan, N B; Callahan, D A; Landen, O L; Jones, O S et al.
Partner: UNT Libraries Government Documents Department

A monitoring sensor management system for grid environments

Description: Large distributed systems, such as computational grids,require a large amount of monitoring data be collected for a variety oftasks, such as fault detection, performance analysis, performance tuning,performance prediction and scheduling. Ensuring that all necessarymonitoring is turned on and that the data is being collected can be avery tedious and error-prone task. We have developed an agent-basedsystem to automate the execution of monitoring sensors and the collectionof event data.
Date: June 1, 2001
Creator: Tierney, Brian; Crowley, Brian; Gunter, Dan; Lee, Jason & Thompson, Mary
Partner: UNT Libraries Government Documents Department

Reflection Mode Imaging with High Resolution X-rayMicroscopy

Description: We report on the first demonstration of imaging microstructures with soft x-ray microscopy operating in reflection geometry. X-ray microscopy in reflection mode combines the high resolution available with x-ray optics, the ability to image thick samples, and to directly image surfaces and interfaces. Future experiments with this geometry will include tuning the incident angle to obtain depth resolution. In combination with XMCD as magnetic contrast mechanism this mode will allow studies of deep buried magnetic interfaces.
Date: April 2, 2005
Creator: Denbeaux, Greg; Fischer, Peter; Salmassi, Farhad; Dunn, Kathleen & Evertsen, James
Partner: UNT Libraries Government Documents Department


Description: This note addresses the various options for the Rapid Cycling Medical Synchrotron (RCMS) RF. The study was divided into three cases, namely non-tuning, tuning and filter. Each case also includes a few options. The primary study was focused on the non-tuning options. However, it was found that it requires too much driver power to cover the wide band and thus causes the cost being too high to be competitive. The proposal of RCMS is not yet clear if it can be approved or not. The results of this study might be useful to other similar machines.
Date: January 22, 2003
Creator: ZHAO,Y.
Partner: UNT Libraries Government Documents Department

A Proposed Plan to Teach College Students How to Tune Pianos

Description: It is the belief of many tuners that the best education for the young tuner is to do apprentice work in a piano factory where he must learn all the construction of the piano from the frame work of the case to the final setting of the tuning pins. It appears that most tuners are men now in the late forties to late fifties and were either factory-trained or apprentice-trained by an experienced tuner. The situation has changed and the apprenticeship method of training professional men such as lawyers and physicians has long since been discarded as a method of education. It is now the generally accepted plan to go to a college or university where such specialized training is given or offered under the direction and tutelage of specialists, and where students learn other essential subjects, the knowledge of which is necessary to the success of any educated man or woman.
Date: August 1945
Creator: Truax, Glenn A.
Partner: UNT Libraries


Description: In this paper we present a multiobjective approach to the dynamic aperture (DA) optimization. Taking the NSLS-II lattice as an example, we have used both sextupoles and quadrupoles as tuning variables to optimize both on-momentum and off-momentum DA. The geometric and chromatic sextupoles are used for nonlinear properties while the tunes are independently varied by quadrupoles. The dispersion and emittance are fixed during tunes variation. The algorithms, procedures, performances and results of our optimization of DA will be discussed and they are found to be robust, general and easy to apply to similar problems.
Date: March 28, 2011
Creator: Yang, L.; Li, Y.; Guo, W. & Krinsky, S.
Partner: UNT Libraries Government Documents Department

A Generalized Framework for Auto-tuning Stencil Computations

Description: This work introduces a generalized framework for automatically tuning stencil computations to achieve superior performance on a broad range of multicore architectures. Stencil (nearest-neighbor) based kernels constitute the core of many important scientific applications involving block-structured grids. Auto-tuning systems search over optimization strategies to find the combination of tunable parameters that maximizes computational efficiency for a given algorithmic kernel. Although the auto-tuning strategy has been successfully applied to libraries, generalized stencil kernels are not amenable to packaging as libraries. Studied kernels in this work include both memory-bound kernels as well as a computation-bound bilateral filtering kernel. We introduce a generalized stencil auto-tuning framework that takes a straightforward Fortran expression of a stencil kernel and automatically generates tuned implementations of the kernel in C or Fortran to achieve performance portability across diverse computer architectures.
Date: May 1, 2009
Creator: Kamil, Shoaib; Chan, Cy; Williams, Samuel; Oliker, Leonid; Shalf, John; Howison, Mark et al.
Partner: UNT Libraries Government Documents Department

Better HMC integrators for dynamical simulations

Description: We show how to improve the molecular dynamics step of Hybrid Monte Carlo, both by tuning the integrator using Poisson brackets measurements and by the use of force gradient integrators. We present results for moderate lattice sizes.
Date: June 1, 2010
Creator: M.A. Clark, Balint Joo, A.D. Kennedy, P.J. Silva
Partner: UNT Libraries Government Documents Department

Further Analysis of Real Beam Line Optics From A Synthetic Beam

Description: Standard closed-orbit techniques for Twiss parameter measurement are not applicable to the open-ended Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab. The evolution of selected sets of real orbits in the accelerator models the behavior of a 'synthetic' beam. This process will be validated against beam profile-based Twiss parameter measurements and should provide the distributed optical information needed to optimize beamline tuning for an open-ended system. This work will discuss the current and future states of this technique, as well as an example of its use in the CEBAF machine.
Date: July 1, 2012
Creator: Ryan Bodenstein, Michael Tiefenback, Yves Roblin
Partner: UNT Libraries Government Documents Department

Reference Undulator Measurement Results

Description: The LCLS reference undulator has been measured 22 times during the course of undulator tuning. These measurements provide estimates of various statistical errors. This note gives a summary of the reference undulator measurements and it provides estimates of the undulator tuning errors. We measured the reference undulator many times during the tuning of the LCLS undulators. These data sets give estimates of the random errors in the tuned undulators. The measured trajectories in the reference undulator are stable and straight to within {+-}2 {micro}m. Changes in the phase errors are less than {+-}2 deg between data sets. The phase advance in the cell varies by less than {+-}2 deg between data sets. The rms variation between data sets of the first integral of B{sub x} is 9.98 {micro}Tm, and the rms variation of the second integral of B{sub x} is 17.4 {micro}Tm{sup 2}. The rms variation of the first integral of B{sub y} is 6.65 {micro}Tm, and the rms variation of the second integral of B{sub y} is 12.3 {micro}Tm{sup 2}. The rms variation of the x-position of the fiducialized beam axis is 35 {micro}m in the final production run This corresponds to an rms uncertainty in the K value of {Delta}K/K = 2.7 x 10{sup -5}. The rms variation of the y-position of the fiducialized beam axis is 4 {micro}m in the final production run.
Date: August 18, 2011
Creator: Wolf, Zachary; Levashov, Yurii; /SLAC & ,
Partner: UNT Libraries Government Documents Department

Beam-Beam Diagnostics from Closed-Orbit Distortion

Description: The authors study the applicability of beam-beam deflection techniques as a tuning tool for asymmetric B factories, focusing on PEP-II as an example. Assuming that the closed orbits of the two beams are separated vertically at the interaction point by a local orbit bump that is nominally closed, they calculate the residual beam orbit distortions due to the beam-beam interaction. Difference orbit measurements, performed at points conveniently distant from the interaction point (IP), provide distinct signatures that can be used to maintain the beams in collision and perform detailed optical diagnostics at the IP. A proposal to test this method experimentally at the TRISTAN ring is briefly discussed. Because of their two-ring structure, asymmetric B factories are likely to require more diagnostics and feedback mechanisms than single-ring colliders in order to guarantee head-on collisions. In addition to the traditional techniques, however, the independence of the two beams allows one to envisage other kinds of beam diagnostics. In this article they investigate one such possibility, by looking at the closed orbit distortion produced by the beam-beam interaction when the beams do not collide exactly head-on. They base this investigation on an analytic model and strong-strong multiparticle simulations. Although the discussion uses the PEP-II design as an example, the conclusion is that this technique is quite a promising diagnostics tool for asymmetric colliders in general.
Date: July 1, 1992
Creator: Furman, M.; Chin, Y.-H.; Eden, J.; Kozanecki, W.; Tennyson, J. & Ziemann, V.
Partner: UNT Libraries Government Documents Department

Linear lattice modeling of the recycler ring at Fermilab

Description: Substantial differences are found in tunes and beta functions between the existing linear model and the real storage ring. They result in difficulties when tuning the machine to new lattice conditions. We are trying to correct the errors by matching the model into the real machine using Orbit Response Matrix (ORM) Fit method. The challenges with ORM particularly in the Recycler ring and the results are presented in this paper.
Date: June 1, 2006
Creator: Xiao, Meiqin; Valishev, Alexander; Nagaslaev, Vladimir P.; /Fermilab; Sajaev, Vadim & /Argonne
Partner: UNT Libraries Government Documents Department

DIMAD Based Interactive Simulation of the CEBAF Accelerator

Description: An X-Windows^(TM) based interactive interface to the DIMAD beam optics program enables users to simulate the adjustment of magnets in tuning various segments of the CEBAF beamline.In addition, users can track the effects of random errors on the path of individual particles as magnets are adjusted.The interface sits on top of the standard DIMAD model, retaining the detailed modeling available with that code.Because X-Windows software was used, the code is portable to any system that has X-Windows and the X-Windows Toolkit available.We give results from the studies simulating the extraction portion of the CEBAF beamline.
Date: May 1, 1991
Creator: Douglas, David & Bickley, Matthew
Partner: UNT Libraries Government Documents Department


Description: As part of the Low-Energy Demonstration Accelerator (LEDA) portion of the Advanced Accelerator Applications (AAA) project we have fabricated and will perform high-power RF tests on Section 2 of the 700-MHz Coupled-Cavity Drift-Tube Linac (CCDTL). This CCDTL section contains six, two-gap accelerating cells. This portion of the CCDTL was designed to accelerate the 100-mA, LEDA RFQ proton beam to 7.3 MeV. This paper reports on the process and results of tuning Section 2 leading up to high-power RF testing.
Date: January 1, 2001
Creator: Rybarcyk, L. J. (Lawrence J.); L.), Wood R. L. (Richard; Leslie, P. O. (Paul O.); Valdiviez, R. (Robert); Cole, M. D. (Michael D.) & Potter, J. M. (James M.)
Partner: UNT Libraries Government Documents Department

A proof-of-principle experiment of the ferroelectric tuner for the 1.3 GHz gun cavity

Description: A novel ferroelectric frequency tuner was developed by the Ornega-P company and was tested at the Brookhaven National Laboratory on a 1.3 GHz RF cavity at room temperature. The tuner is based on the ferroelectric property of having a permittivity variable with an applied electric field. The achievable frequency tuning range can be estimated from the reactive impedance change due to an applied voltage via a S{sub 11} measurement at the tuner port. The frequency shift can be measured directly with a S{sub 21} measurement across the gun cavity with the tuner connected and activated. The frequency change due to an applied 5 kV obtained from the two methods is in reasonable agreement. The reactive impedance measurement yields a value in the range between 3.2 kHz and 14 kHz, while 9 kHz is the result from the direct measurement. The detail description of the experiment and the analysis will be discussed in the paper.
Date: May 4, 2009
Creator: Hahn,H.; Choi, E.; Shchelkunov, S. V.; Hirshfield, J.; Kazakov, S. & Shschelkunov, S.
Partner: UNT Libraries Government Documents Department