219 Matching Results

Search Results

Results: 1 - 24 next
open access

High-precision reflectometry of multilayer coatings for extreme ultraviolet lithography

Description: Synchrotron-based reflectometry is an important technique for the precise determination of optical properties of reflective multilayer coatings for Extreme Ultraviolet Lithography (EUVL). Multilayer coatings enable normal incidence reflectances of more than 65% in the wavelength range between 11 and 15 nm. In order to achieve high resolution and throughput of EUVL systems, stringent requirements not only apply to their mechanical and optical layout, but also apply to the optical properties of t… more
Date: December 29, 1999
Creator: Wedowski, M; Underwood, J H; Gullikson, E M; Bajt, S; Folta, J A; Kearney, P A et al.
Partner: UNT Libraries Government Documents Department
open access

Gold Beam Losses at the AGS Booster Injection.

Description: Gold beam injection efficiency decreases in proportional to the beam loss in the AGS Booster. A close look shows that large number of electrons, ions, and neutral particles are created when the gold beam scrapes wall. To investigate the neutral particle production due to the beam loss, local vacuum measurement was made during the 1998 run. It shows that the pressure created by the Booster Au{sup 31+} beam loss at injection has a 35 ms decay time constant. The beam loss created pressure bump in … more
Date: March 29, 1999
Creator: Zhang, S. Y. & Ahrens, L. A.
Partner: UNT Libraries Government Documents Department
open access

A Cupronickel Rotating Band Pion Production Target for Muon Colliders.

Description: A conceptual design is presented for a high power cupronickel pion production target. It forms a circular band in a horizontal plane with approximate dimensions of: 2.5 meters radius, 6 cm high and 0.6 cm thick. The target is continuously rotated at 3 m/s to carry heat away from the production region to a water cooling channel. Bunches of 16 GeV protons with total energies of 270 kl and repetition rates of 15 Hz are incident tangentially to arc of the target along the symmetry axis of a 20 Tesl… more
Date: March 29, 1999
Creator: King, B. J.; Weggel, R. J.; Mokhov, N. V. & Moser, S. S.
Partner: UNT Libraries Government Documents Department
open access

Precision Magnetic Elements for the SNS Storage Ring.

Description: Magnetic elements for an accumulator storage ring for a 1 GeV Spallation Neutron Source (SNS) have been under design. The accumulation of very high intensity protons in a storage ring requires beam optical elements of very high purity to minimize higher order resonances in the presence of space charge. The parameters of the elements required by the accumulator lattice design have been reported. The dipoles have a 17cm gap and are 124cm long. The quadrupoles have a physical length to aperture di… more
Date: March 29, 1999
Creator: Danby, G.; Jackson, J. & Spataro, C.
Partner: UNT Libraries Government Documents Department
open access

A P-Carbon CNI Polarimeter for RHIC.

Description: The RHIC spin program requires excellent polarimetry so that the knowledge of the beam polarization does not limit the errors on the experimental measurements. However, polarimetry of proton beams with energies higher than about 30GeV poses a difficult challenge. For polarization monitoring during operation, a fast and reliable polarimeter is required that produces a polarization measurement with a 10% relative error within a few minutes. The p-Carbon elastic scattering in the Coulomb-Nuclear-S… more
Date: March 29, 1999
Creator: Huang, H.; Bai, M.; Bunce, G.; Makdisi, Y.; Roser, T.; Imai, K. et al.
Partner: UNT Libraries Government Documents Department
open access

Design of a Resonant Extraction System for the AGS Booster.

Description: The Booster Application Facility (BAF) will employ heavy ion beams of many different ion species and at beam energies ranging from 0.04 to 3.07 GeV/nucleon. Resonant extraction is required in order to deliver a continuous stream of particles. In this report we describe the beam requirements and the system design. The basic design is a third integer resonant extraction process which employs a single thin magnetic septum and a thick septum ejector magnet The expected extraction efficiency is abou… more
Date: March 29, 1999
Creator: Brown, K.; Cullen, J.; Glenn, J. W.; Lee, Y. Y.; Mcnerney, A.; Niederer, J. et al.
Partner: UNT Libraries Government Documents Department
open access

RHIC Beam Loss Monitor System Initial Operation.

Description: The RHIC Beam Loss Monitor (BLM) System is designed to prevent beam loss quenching of the superconducting magnets, and acquire loss data. Four hundred ion chambers are located around the rings to detect losses. The required 8-decade range in signal current is compressed using an RC pre- integrator ahead of a low current amplifier. A beam abort may be triggered if fast or slow losses exceed programmable threshold levels. A micro-controller based VME module sets references and gains and reads tri… more
Date: March 29, 1999
Creator: Witkover, R. L.; Michnoff, R. J. & Geller, J. M.
Partner: UNT Libraries Government Documents Department
open access

The Design of a Liquid Lithium Lens for a Muon Collider.

Description: The last stage of ionization cooling for the muon collider requires a multistage liquid lithium lens. This system uses a large ({approx}0.5 MA) pulsed current through liquid lithium to focus the beam while energy loss in the lithium removes momentum which will be replaced by linacs. The beam optics are designed to maximize the 6 dimensional transmission from one lens to the next while minimizing emittance growth. The mechanical design of the lithium vessel is constrained by a pressure pulse due… more
Date: March 29, 1999
Creator: Hassanein, A.; Norem, J.; Reed, C.; Palmer, R. B.; Silvestrov, G.; Vsevolozhskaya, T. A. et al.
Partner: UNT Libraries Government Documents Department
open access

Beam Instrumentation for the Spallation Neutron Source Ring.

Description: The Spallation Neutron Source (SNS) will be constructed by a multi-laboratory collaboration with BNL responsible for the transfer lines and ring. [1] The 1 MW beam power necessitates careful monitoring to minimize un-controlled loss. This high beam power will influence the design of the monitors in the high energy beam transport line (HEBT) from linac to ring, in the ring, and in the ring-to-target transfer line (RTBT). The ring instrumentation must cover a 3-decade range of beam intensity duri… more
Date: March 29, 1999
Creator: Witkover, R. L.; Cameron, P. R.; Shea, T. J.; Connolly, R. C. & Kesselman, M.
Partner: UNT Libraries Government Documents Department
open access

Beam-Loss Driven Design Optimization for the Spallation Neutron Source (SNS) Ring.

Description: This paper summarizes three-stage design optimization for the Spallation Neutron Source (SNS) ring: linear machine design (lattice, aperture, injection, magnet field errors and misalignment), beam core manipulation (painting, space charge, instabilities, RF requirements), and beam halo consideration (collimation, envelope variation, e-p issues etc.).
Date: March 29, 1999
Creator: Wei, J.; Beebe-Wang, J.; Blaskiewicz, M.; Cameron, P.; Danby, G.; Gardner, C. J. et al.
Partner: UNT Libraries Government Documents Department
open access

A High Power RF Coupler Design for Muon Cooling RF Cavities.

Description: We present a high power RF coupler design for an interleaved {pi}/2 805 MHz standing wave accelerating structure proposed for an muon cooling experiment at FNAL. The coupler, in its simplest form, is a rectangular waveguide directly connected to an accelerating Cell through an open slot on the cavity side-wall or end-plates. Two of such couplers are needed to feed the interleaved cavities. Current high power RF test requires the coupler to be at critical coupling. Numerical simulations on the c… more
Date: March 29, 1999
Creator: Corlett, J.; Li, Derun; Rimmer, R.; Holtkamp, N.; Moretti, A. & Kirk, H. G.
Partner: UNT Libraries Government Documents Department
open access

Interaction Region Local Correction for the Large Hadron Collider.

Description: The performance of the Large Hadron Collider (LHC) at collision energy is limited by the field quality of the interaction region (IB) quadrupoles and dipoles. In this paper we study the impact of the expected field errors of these magnets on the dynamic aperture (DA). Since the betatron phase advance is well defined for magnets that are located in regions of large beta functions, local corrections can be very effective and robust. We compare possible compensation schemes and propose a corrector… more
Date: March 29, 1999
Creator: Wei, J.; Fischer, W.; Ptitsin, V.; Ostojic, R. & Strait, J.
Partner: UNT Libraries Government Documents Department
open access

Muon Colliders - Ionization Cooling and Solenoids.

Description: For a muon collider, to obtain the needed luminosity, the phase space volume must be greatly reduced within the muon life time. The ionization cooling is the preferred method used to compress the phase space and reduce the emittance to obtain high luminosity muon beams. Alternating solenoid lattices has been proposed for muon colliders, where the emittance are huge. We present an overview, discuss formalism, transfer maps for solenoid magnets and beam dynamics.
Date: March 29, 1999
Creator: Parsa, Z.
Partner: UNT Libraries Government Documents Department
open access

The Application of the SXF Lattice Description and the UAL Software Environment to the Analysis of the LHC.

Description: A software environment for accelerator modeling has been developed which includes the UAL (Unified Accelerator Library), a collection of accelerator physics libraries with a Per1 interface for scripting, and the SXF (Standard eXchange Format), a format for accelerator description which extends the MAD sequence by including deviations from design values. SXF interfaces have been written for several programs, including MAD9 and MAD8 via the doom database, Cosy, TevLat and UAL itself, which includ… more
Date: March 29, 1999
Creator: Fischer, W.; Pilat, F. & Ptitson, V.
Partner: UNT Libraries Government Documents Department
open access

Processing and Analysis of the Measured Alignment Errors for Rhic.

Description: All elements of the Relativistic Heavy Ion Collider (RHIC) have been installed in ideal survey locations, which are defined as the optimum locations of the fiducials with respect to the positions generated by the design. The alignment process included the presurvey of all elements which could affect the beams. During this procedure a special attention was paid to the precise determination of the quadrupole centers as well as the roll angles of the quadrupoles and dipoles. After installation the… more
Date: March 29, 1999
Creator: Pilat, F.; Hemmer, M.; Ptitsin, V.; Tepikian, S. & Trbojevic, D.
Partner: UNT Libraries Government Documents Department
open access

US-LHC Magnet Database and Conventions.

Description: The US-LHC Magnet Database is designed for production-magnet quality assurance, field and alignment error impact analysis, cryostat assembly assistance, and ring installation assistance. The database consists of tables designed to store magnet field and alignment measurements data and quench data. This information will also be essential for future machine operations including local IR corrections.
Date: March 29, 1999
Creator: Wei, J.; McChesney, D.; Jain, A.; Peggs, S.; Pilat, F.; Bottura, L. et al.
Partner: UNT Libraries Government Documents Department
open access

Feedback Design Method Review and Comparison.

Description: Different methods for feedback designs are compared. These includes classical Proportional Integral Derivative (P. I. D.), state variable based methods like pole placement, Linear Quadratic Regulator (L. Q. R.), H-infinity and p-analysis. These methods are then applied for the design and analysis of the RHIC phase and radial loop, yielding a performance, stability and robustness comparison.
Date: March 29, 1999
Creator: Onillon, E.
Partner: UNT Libraries Government Documents Department
open access

A Pulsed Modulator Power Supply for the g-2 Muon Storage Ring Injection Kicker

Description: This paper describes the pulse modulator power supplies used to drive the kicker magnets that inject the muon beam into the g-2 storage ring that has been built at Brookhaven. Three modulators built into coaxial structures consisting of a series circuit of an energy storage capacitor, damping resistor and a fast thyratron switch are used to energize three magnets that kick the beam into the proper orbit. A 100 kV charging power supply is used to charge the capacitor to 95 kV. the damping resist… more
Date: March 29, 1999
Creator: Mi, J.; Lee, Y. Y.; Morse, W. M.; Pai, C.; Pappas, G.; Sanders, R. et al.
Partner: UNT Libraries Government Documents Department
open access

Two recent results on B physics from CDF

Description: Preliminary results from two recent CDF b physics analyses are presented. The first obtains sin(2{beta})=0.79<sup>+0.41</sup><sub>-0.44</sub> from a measurement of the asymmetry in B<sup>0</sup>, {anti B<sup>0</sup>} {yields} J/{psi}K<sup>0</sup><sub>s</sub> decays, providing the best direct indication so far that CP invariance is violated in the b sector. The second obtains new results on the parity even (A<sub>0</sub> and A<sub>{parallel}</sub>) and odd (A<sub>{perpendicular}</sub>) polarizat… more
Date: June 29, 1999
Creator: Schmidt, M. P.
Partner: UNT Libraries Government Documents Department
open access

The Sloan Digital Sky Survey data acquisition system, and early results

Description: The Sloan Digital Sky Survey will systematically map one- quarter of the sky, producing detailed images in five color bands and determining the positions and absolute bright- nesses of more than 100 million celestial objects. It will also measure the redshifts of a million selected galaxies and of 100,000 quasars, yielding a three-dimensional map of the universe through a volume one hundred times larger than that explored to date. The SDSS collaboration is currently in the process of commission… more
Date: June 29, 1999
Creator: J. Annis, J. Bakken, D. Holmgren, D. Petravick, R. Rechenmacher
Partner: UNT Libraries Government Documents Department
open access

Non-SUSY exotic particle searches at the Tevatron

Description: Between 1992 and 1995, the CDF and D0 collaborations collected data from p{anti p} collisions at {radical}s = 1.8 TeV. Recently, several analyses of this data have been performed in search of evidence for various non-Supersymmetric exotic particles. As no evidence for the existence of these particles is observed, confidence level limits are established for exotic particle predictions from various theoretical models. Analyses presented here include searches for Standard Model Higgs, technicolor … more
Date: June 29, 1999
Creator: Cassada, J.
Partner: UNT Libraries Government Documents Department
open access

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 interpol… more
Date: June 29, 1999
Creator: Eichel, Paul H.; Jakowatz, Charles V., Jr. & Yocky, David A.
Partner: UNT Libraries Government Documents Department
open access

Plutonium-238 Transuranic Waste Decision Analysis

Description: Five transuranic (TRU) waste sites in the Department of Energy (DOE) complex, collectively, have more than 2,100 cubic meters of Plutonium-238 (Pu-238) TRU waste that exceed the wattage restrictions of the Transuranic Package Transporter-II (TRUPACT-11). The Waste Isolation Pilot Plant (WIPP) is being developed by the DOE as a repository for TRU waste. With the Waste Isolation Pilot Plant (WIPP) opening in 1999, these sites are faced with a need to develop waste management practices that will e… more
Date: June 29, 1999
Creator: Brown, Mike; Lechel, David J. & Leigh, C.D.
Partner: UNT Libraries Government Documents Department
open access

New Tevatron measurements of the W boson mass

Description: The CDF and D0 Collaborations obtain new measurements of the W boson mass using data taken between 1994 and 1996. CDF updates the previous result obtained from W {yields} {mu}{nu} decays, reducing many systematic uncertainties, and performs a new measurement using a high statistics sample of W {yields} e{nu} events; combining these measurements with the previous ones yields M<sub>W</sub><sup>CDF</sup> =80.433 &plusmn; 0.079 GeV/c &sup2;. D0 also extends the previous result, based on central ele… more
Date: June 29, 1999
Creator: Dorigo, T.
Partner: UNT Libraries Government Documents Department
Back to Top of Screen