29 Matching Results

Search Results

Advanced search parameters have been applied.
in subjects: "Cern"  
Results: 1 - 24 next
open access

The Education and Outreach Project of ATLAS - A New Participant inPhysics Education

Description: The ATLAS experiment at the Large Hadron Collider at CERN has a substantial collaborative Education and Outreach project. This article describes its activities and how it promotes physics to students around the world. With the extraordinary possibility to make groundbreaking discoveries, the ATLAS Experiment [1] at the Large Hadron Collider at CERN can play an important role in promoting contemporary physics at school. For many years ATLAS has had a substantial collaborative Education and Outre… more
Date: April 15, 2006
Creator: Barnett, R. Michael & Johansson, K. Erik
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Benchmark of the IMPACT Code for High Intensity Beam DynamicsSimulation

Description: The IMPACT (Integrated Map and Particle Accelerator Tracking) code was first developed under Computational Grand Challenge project in the mid 1990s [1]. It started as a three-dimensional (3D) data parallel particle-in-cell (PIC) code written in High Performance Fortran. The code used a split-operator based method to solve the Hamiltonian equations of motion. It contained linear transfer maps for drifts, quadrupole magnets and rf cavities. The space-charge forces were calculated using an FFT-bas… more
Date: November 16, 2006
Creator: Qiang, J. & Ryne, R.D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

New experimental measurements of electron clouds in ion beams with large tune depression

Description: We study electron clouds in high perveance beams (K = 8E-4) with a large tune depression of 0.2 (defined as the ratio of a single particle oscillation response to the applied focusing fields, with and without space charge). These 1 MeV, 180 mA, K+ beams have a beam potential of +2 kV when electron clouds are minimized. Simulation results are discussed in a companion paper [J-L. Vay, this Conference]. We have developed the first diagnostics that quantitatively measure the accumulation of electro… more
Date: March 16, 2006
Creator: Molvik, A W; Covo, M K; Cohen, R H; Friedman, A; Bieniosek, F M; Leister, C M et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

SIMULATION AND ANALYSIS OF MICROWAVE TRANSMISSION THROUGH ANELECTRON CLOUD, A COMPARISON OF RESULTS

Description: Simulation studies for transmission of microwaves through electron clouds show good agreement with analytic results. The electron cloud produces a shift in phase of the microwave. Experimental observation of this phenomena would lead to a useful diagnostic tool for accessing the local density of electron clouds in an accelerator. These experiments are being carried out at the CERN SPS and the PEP-II LER at SLAC and is proposed to be done at the Fermilab main injector. In this study, a brief ana… more
Date: April 15, 2006
Creator: Sonnad, Kiran G.; Furman, Miguel; Veitzer, Seth A. & Cary, John
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Design and performance of the alignment system for the CMS muon endcaps

Description: The alignment system for the CMS Muon Endcap detector employs several hundred sensors such as optical 1-D CCD sensors illuminated by lasers and analog distance- and tilt-sensors to monitor the positions of one sixth of 468 large Cathode Strip Chambers. The chambers mounted on the endcap yoke disks undergo substantial deformation on the order of centimeters when the 4T field is switched on and off. The Muon Endcap alignment system is required to monitor chamber positions with 75-200 {micro}m acc… more
Date: December 1, 2006
Creator: Hohlmann, Marcus; Baksay, Gyongyi; Browngold, Max; Dehmelt, Klaus; Guragain, Samir; Andreev, Valery et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Phenomenology of the left-right twin Higgs model

Description: The twin Higgs mechanism was proposed recently to solve the little hierarchy problem. We study the implementation of the twin Higgs mechanism in left-right models. At the TeV scale, heavy quark and gauge bosonsappear, with rich collider phenomenology. In addition, there are extra Higgs bosons, some of which couple to both the standard model fermion sector and the gauge sector, while others couple to the gauge bosons only. We present the particle spectrum and study the general features of the co… more
Date: November 2, 2006
Creator: Goh, Hock-Seng; Goh, Hock-Seng & Su, Shufang
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Assembly and Test of SQ01b, a Nb3Sn Quadrupole Magnet for the LHC Accelerator Research Program

Description: The US LHC Accelerator Research Program (LARP) consists of four US laboratories (BNL, FNAL, LBNL, and SLAC) collaborating with CERN to achieve a successful commissioning of the LHC and to develop the next generation of Interaction Region magnets. In 2004, a large aperture Nb{sub 3}Sn racetrack quadrupole magnet (SQ01) has been fabricated and tested at LBNL. The magnet utilized four subscale racetrack coils and was instrumented with strain gauges on the support structure and directly over the co… more
Date: June 1, 2006
Creator: Ferracin, P.; Ambrosio, G.; Bartlett, S. E.; Bordini, B.; Carcagno, R. H.; Caspi, S. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

High-Performance Secure Database Access Technologies for HEP Grids

Description: The Large Hadron Collider (LHC) at the CERN Laboratory will become the largest scientific instrument in the world when it starts operations in 2007. Large Scale Analysis Computer Systems (computational grids) are required to extract rare signals of new physics from petabytes of LHC detector data. In addition to file-based event data, LHC data processing applications require access to large amounts of data in relational databases: detector conditions, calibrations, etc. U.S. high energy physicis… more
Date: April 17, 2006
Creator: Vranicar, Matthew & Weicher, John
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Electronic Desorption of gas from metals

Description: During heavy ion operation in several particle accelerators world-wide, dynamic pressure rises of orders of magnitude were triggered by lost beam ions that bombarded the vacuum chamber walls. This ion-induced molecular desorption, observed at CERN, GSI, and BNL, can seriously limit the ion beam lifetime and intensity of the accelerator. From dedicated test stand experiments we have discovered that heavy-ion induced gas desorption scales with the electronic energy loss (dE{sub e}/dx) of the ions… more
Date: November 2, 2006
Creator: Molvik, A W; Kollmus, H; Mahner, E; Covo, M K; Bender, M; Bieniosek, F M et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Measurement and correction of the 3rd order resonance in the Tevatron

Description: At Fermilab Tevatron BPM system has been recently upgraded resulting much better accuracy of beam position measurements and improvements of data acquisition for turn-by-turn measurements. That allows one to record the beam position at each turn for 8000 turns for all BPMs (118 in each plane) with accuracy of about 10-20 {micro}m. In the last decade a harmonic analysis tool has been developed at CERN that allows relating each FFT line derived from the BPM data with a particular non-linear resona… more
Date: June 1, 2006
Creator: Schmidt, F.; Alexahin, Y.; Lebedev, V.; Still, D. & Valishev, A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

INSTABILITES IN NB3SN WIRES.

Description: High current-density Nb{sub 3}Sn strands made by internal-tin routes are not stable against flux jumps at low fields. Since flux jumps release heat, they can initiate quenching if thermal conductivity to the liquid helium is poor. To make matters worse, tin is a potent contaminant of copper, and reaction of strands to maximize performance leads to the loss of thermal conductivity. We discuss how the root of a solution of this problem lies in optimizing two parameters, RRR and J{sub c}, instead … more
Date: April 3, 2006
Creator: COOLEY, L. & GHOSH, A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Update on electron-cloud power deposition for the LHC arcdipoles

Description: We revisit the estimation of the power deposited by the electron cloud (EC) in the arc dipoles of the LHC by means of simulations. We adopt, as simulation input, a set of electron-related parameters closely resembling those used in recent simulations at CERN [1]. We explore values for the bunch population Nb in the range 0.4 x 10^11 <= Nb <=1.6 x 10^11, peak secondary electron yield (SEY) delta max in the range 1.0 <= delta max <= 2.0, and bunch spacing tb either 25 or 75 ns. For tb=25 ns we fi… more
Date: January 30, 2006
Creator: Furman, Miguel A. & Chaplin, Vernon H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Nuclear Reaction and Structure Databases of the National Nuclear Data Center.

Description: We discuss nuclear data resources of the National Nuclear Data Center (NNDC) of relevance to nuclear astrophysics applications. These resources include databases, tools and powerful web service at www.nndc.bnl.gov. Our objective is to provide an overview of nuclear databases, related products and demonstrate nuclear astrophysics potential of the ENDF/B-VII beta2 library. A detailed discussion on the Maxwellian neutron capture cross sections obtained from the ENDF/B-VII beta2 library is presente… more
Date: June 23, 2006
Creator: Pritychenko, B.; Herman, M. W.; Mughabghab, S. F.; Oblozinsky, P. & Sonzogni, A. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Summary of coupling and tune feedback results during RHIC run 6, and possible implications for LHC commissioning

Description: Early efforts to implement tune feedback during the acceleration ramp in RHIC were hampered by large betatron coupling, as well as the requirement for large dynamic range. Both problems have been addressed, the first by implementation of continuous measurement of coupling, and the second by the development of an improved analog front end. With these improvements, simultaneous coupling and tune feedback were successfully implemented for acceleration ramp development during RHIC Run 6. During the… more
Date: June 1, 2006
Creator: Cameron, P.; DellaPenna, A.; Hoff, L. T.; Luo, Y.; Marusic, A.; Ptitsyn, V. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Wire bond vibration of forward pixel tracking detector of CMS

Description: Wire bonds of the Forward Pixel (FPix) tracking detectors are oriented in the direction that maximizes Lorentz Forces relative to the 4 Tesla field of the Compact Muon Solenoid (CMS) Detector's magnet. The CMS Experiment is under construction at the Large Hadron Collider at CERN, Geneva, Switzerland. We were concerned about Lorentz Force oscillating the wires at their fundamental frequencies and possibly fracturing or breaking them at their heels, as happened with the CDF wire bonds. This paper… more
Date: October 1, 2006
Creator: Atac, M.; Gobbi, B.; Kwan, S.; Pischalnikov, Y.; Spencer, E.; Sellberg, G. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Feasibility study of Nb3Al Rutherford cable for high field accelerator magnet application

Description: Feasibility study of Cu stabilized Nb{sub 3}Al strand and Rutherford cable for the application to high field accelerator magnets are being done at Fermilab in collaboration with NIMS. The Nb{sub 3}Al strand, which was developed and manufactured at NIMS in Japan, has a non-copper Jc of about 844 A/mm{sup 2} at 15 Tesla at 4.2 K, a copper content of 50%, and filament size of about 50 microns. Rutherford cables with 27 Nb{sub 3}Al strands of 1.03 mm diameter were fabricated and tested. Quench test… more
Date: August 1, 2006
Creator: Yamada, R.; /Fermilab; Kikuchi, A.; Lab., /Tsukuba Magnet; Ambrosio, G.; Andreev, N. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Colliders as a simultaneous probe of supersymmetric dark matter and Terascale cosmology

Description: Terascale supersymmetry has the potential to provide a natural explanation of the dominant dark matter component of the standard {Lambda}CDM cosmology. However once we impose the constraints on minimal supersymmetry parameters from current particle physics data, a satisfactory dark matter abundance is no longer prima facie natural. This Neutralino Tuning Problem could be a hint of nonstandard cosmology during and/or after the Terascale era. To quantify this possibility, we introduce an alternat… more
Date: August 1, 2006
Creator: Barenboim, Gabriela; U., /Valencia; Lykken, Joseph D. & /Fermilab
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Report of the Event Tag Review and Recommendation Group

Description: In order to facilitate access to the large volumes of data (multiple petabytes per year) which will be produced during data taking and Monte Carlo production at ATLAS, work has proceeded on building a system of event-level metadata to allow selections of a subset of events to use as input to an analysis. This was included in the ATLAS Computing Model and was first studied and implemented by the Physics Analysis Tools group based on the decisions of the ESD/AOD Task Force. They used tools develo… more
Date: April 12, 2006
Creator: Group, ATLAS; Assamagan, Kétévi A.; Barberis, Dario; Bentvelsen, Stan; Brooijmans, Gustaaf; Cranmer, Kyle et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Electron Production and Collective Field Generation in Intense Particle Beams

Description: Electron cloud effects (ECEs) are increasingly recognized as important, but incompletely understood, dynamical phenomena, which can severely limit the performance of present electron colliders, the next generation of high-intensity rings, such as PEP-II upgrade, LHC, and the SNS, the SIS 100/200, or future high-intensity heavy ion accelerators such as envisioned in Heavy Ion Inertial Fusion (HIF). Deleterious effects include ion-electron instabilities, emittance growth, particle loss, increase … more
Date: February 9, 2006
Creator: Molvik, A W; Vay, J; Cohen, R; Friedman, A; Lee, E; Verboncoeur, J et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

EMC Diagnosis and Corrective Actions for Silicon Strip Tracker Detectors

Description: The tracker sub-system is one of the five sub-detectors of the Compact Muon Solenoid (CMS) experiment under construction at CERN for the Large Hadron Collider (LHC) accelerator. The tracker subdetector is designed to reconstruct tracks of charged sub-atomic particles generated after collisions. The tracker system processes analogue signals from 10 million channels distributed across 14000 silicon micro-strip detectors. It is designed to process signals of a few nA and digitize them at 40 MHz. T… more
Date: June 6, 2006
Creator: Arteche, F. & Rivetta, C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Measurement of b-quark Jet Shapes at CDF

Description: The main topic of this thesis is the measurement of b-quark jet shapes at CDF. CDF is an experiment located at Fermilab, in the United States, which studies proton-antiproton collisions at a center of mass energy of 1.96TeV. To reach this energy, the particles are accelerated using the Tevatron accelerator which is currently the highest energy collider in operation. The data used for this analysis were taken between February 2002 and September 2004 and represent an integrated luminosity of abou… more
Date: March 1, 2006
Creator: Lister, Alison
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
open access

Searches for Astrophysical and Cosmological Axions

Description: The axion remains, after nearly 30 years, the most compelling and elegant solution to the strong-CP problem, i.e. why this symmetry is protected in QCD in spite of CP violation elsewhere. The axion is expected to be extremely light, and possess extraordinarily feeble couplings to matter and radiation. Because of its small couplings, the axion has defied experimental confirmation and is unlikely to be discovered in conventional laboratory experiments (i.e. production-detection). Nevertheless, a … more
Date: May 3, 2006
Creator: Asztalos, S J; Rosenberg, L J; van Bibber, K; Sikivie, P & Zioutas, K
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

QCD Corrections to Higgs Pair Production in Bottom Quark Fusion

Description: We present a complete next-to-leading order (NLO) calculation for the total cross section of inclusive Higgs pair production via bottom-quark fusion (b{bar b} {yields} hh) at the CERN Large Hadron Collider (LHC) in the Standard Model. The NLO QCD corrections lead to less dependence on the renormalization scale ({mu}{sub R}) and the factorization scale ({mu}{sub F}) than the leading-order (LO) cross section, and they significantly increase the LO cross section. The rate for inclusive Higgs pair … more
Date: October 1, 2006
Creator: Dawson, Sally; /Brookhaven; Kao, Chung; U., /Fermilab /Oklahoma; Wang, Yili; Williams, Peter et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

COMPUTATIONAL SCIENCE CENTER

Description: Computational Science is an integral component of Brookhaven's multi science mission, and is a reflection of the increased role of computation across all of science. Brookhaven currently has major efforts in data storage and analysis for the Relativistic Heavy Ion Collider (RHIC) and the ATLAS detector at CERN, and in quantum chromodynamics. The Laboratory is host for the QCDOC machines (quantum chromodynamics on a chip), 10 teraflop/s computers which boast 12,288 processors each. There are two… more
Date: November 1, 2006
Creator: DAVENPORT, J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
Back to Top of Screen