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729 Matching Results
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Expected Performance of the ATLAS Experiment - Detector, Trigger and Physics
The Large Hadron Collider (LHC) at CERN promises a major step forward in the understanding of the fundamental nature of matter. The ATLAS experiment is a general-purpose detector for the LHC, whose design was guided by the need to accommodate the wide spectrum of possible physics signatures. The major remit of the ATLAS experiment is the exploration of the TeV mass scale where groundbreaking discoveries are expected. In the focus are the investigation of the electroweak symmetry breaking and linked to this the search for the Higgs boson as well as the search for Physics beyond the Standard Model. In this report a detailed examination of the expected performance of the ATLAS detector is provided, with a major aim being to investigate the experimental sensitivity to a wide range of measurements and potential observations of new physical processes. An earlier summary of the expected capabilities of ATLAS was compiled in 1999 [1]. A survey of physics capabilities of the CMS detector was published in [2]. The design of the ATLAS detector has now been finalised, and its construction and installation have been completed [3]. An extensive test-beam programme was undertaken. Furthermore, the simulation and reconstruction software code and frameworks have …
Date:
November 28, 2011
Creator:
Aad, G.; Abat, E.; Abbott, B.; Abdallah, J.; Abdelalim, A. A.; Abdesselam, A. et al.
Object Type:
Article
System:
The UNT Digital Library
Performance of the new EBIS preinjector
The construction and initial commissioning phase of a new heavy ion preinjector was completed at Brookhaven in September, 2010, and the preinjector is now operational. This preinjector, using an EBIS source to produce high charge state heavy ions, provided helium and neon ion beams for use at the NASA Space Radiation Laboratory in the Fall of 2010, and gold and uranium beams are being commissioned during the 2011 run cycle for use in RHIC. The EBIS operates with an electron beam current of up to 10 A, to produce mA level currents in 10-40 {micro}s beam pulses. The source is followed by an RFQ and IH linac to accelerate ions with q/m > 0.16 to an energy of 2 MeV/amu, for injection into the Booster synchrotron. The performance of the preinjector is presented, including initial operational experience for the NASA and RHIC programs.
Date:
March 28, 2011
Creator:
Alessi, J.; Beebe, E.; Binello, S.; Gardner, C.; Gould, O.; Hoff, L. et al.
Object Type:
Article
System:
The UNT Digital Library
The Gray Wolf and the Endangered Species Act: A Brief Legal History
This report provides a brief history of the laws, regulations, and lawsuits related to the wolf's protected status.
Date:
March 28, 2011
Creator:
Alexander, Kristina
Object Type:
Report
System:
The UNT Digital Library
Gray Wolves Under the Endangered Species Act: Distinct Population Segments and Experimental Populations
This report analyzes the distinct population segments (DPS) designation process as it is applied to the gray wolf. It also examines experimental populations of wolves under the Endangered Species Act (ESA) and their protections.
Date:
February 28, 2011
Creator:
Alexander, Kristina & Corn, M. L.
Object Type:
Report
System:
The UNT Digital Library
Ready, set, go . . . well maybe
The agenda for this presentation is: (1) understand organizational readiness for changes; (2) review benefits and challenges of change; (3) share case studies of ergonomic programs that were 'not ready' and some that were 'ready'; and (4) provide some ideas for facilitating change.
Date:
February 28, 2011
Creator:
Alexandre, Melanie M & Bartolome, Terri-Lynn C
Object Type:
Article
System:
The UNT Digital Library
The machine protection system for the R&D energy recovery LINAC
The Machine Protection System (MPS) is a device-safety system that is designed to prevent damage to hardware by generating interlocks, based upon the state of input signals generated by selected sub-systems. It protects all the key machinery in the R&D Project called the Energy Recovery LINAC (ERL) against the high beam current. The MPS is capable of responding to a fault with an interlock signal within several microseconds. The ERL MPS is based on a National Instruments CompactRIO platform, and is programmed by utilizing National Instruments' development environment for a visual programming language. The system also transfers data (interlock status, time of fault, etc.) to the main server. Transferred data is integrated into the pre-existing software architecture which is accessible by the operators. This paper will provide an overview of the hardware used, its configuration and operation, as well as the software written both on the device and the server side.
Date:
March 28, 2011
Creator:
Altinbas, Z.; Kayran, D.; Jamilkowski, J.; Lee, R.C. & Oerter, B.
Object Type:
Article
System:
The UNT Digital Library
Design and Factory Test of the E /E- Frascati Linear Accelerator for DAFNE
The electron-positron accelerator for the DAFNE project has been built and is in test at Titan Beta in Dublin, CA. This S-Band RF linac system utilizes four 45 MW sledded klystrons and 16-3 m accelerating structures to achieve the required performance. It delivers a 4 ampere electron beam to the positron converter and accelerates the resulting positrons to 550 MeV. The converter design uses a 4.3T pulsed tapered flux compressor along with a pseudo-adiabatic tapered field to a 5 KG solenoid over the first two positron accelerating sections. Quadrupole focusing is used after 100 MeV. The system performance is given in Table 1. This paper briefly describes the design and development of the various subassemblies in this system and gives the initial factory test data.
Date:
November 28, 2011
Creator:
Anamkath, H.; Lyons, S.; Nett, D.; Treas, P.; Whitham, K.; Zante, T. et al.
Object Type:
Article
System:
The UNT Digital Library
Design and Fabrication of a Single-Aperture 11T Nb3Sn Dipole Model for LHC Upgrades
The planned upgrade of the LHC collimation system includes additional collimators to be installed in the dispersion suppressor areas of points 2, 3 and 7. To provide the necessary longitudinal space for the collimators, a replacement of 8.33 T Nb-Ti LHC main dipoles with 11 T dipoles based on Nb{sub 3}Sn superconductor compatible with the LHC lattice and main systems is being considered. To demonstrate this possibility FNAL and CERN have started a joint program to develop a 2 m long single-aperture dipole magnet with the nominal field of 11 T at {approx}11.85 kA current and 60 mm bore. This paper describes the demonstrator magnet magnetic and mechanical designs and analysis, coil fabrication procedure. The Nb{sub 3}Sn strand and cable parameters and test results are also reported.
Date:
November 28, 2011
Creator:
Andreev, N.; Apollinari, G.; Barzi, E.; Bossert, R.; Nobrega, F.; Novitski, I. et al.
Object Type:
Article
System:
The UNT Digital Library
Design Construction and Test Results of a HTS Solenoid For Energy Recovery Linac
An innovative feature of the proposed Energy Recovery Linac (ERL) is the use of a solenoid made with High Temperature Superconductor (HTS) with the Superconducting RF cavity. The use of HTS allows solenoid to be placed in close proximity to the cavity and thus provides early focusing of the electron beam. In addition, cryogenic testing at {approx}77 K is simpler and cheaper than 4 K testing. This paper will present the design, construction and test results of this HTS solenoid. The HTS solenoid in the proposed ERL will be situated in the transition region between the superconducting cavity at {approx}4 K and the cryostat at the room temperature. Solenoid inside the cryogenic structure provides an early focusing and hence low emittance beam. The temperature in the transition region will be too high for a conventional low temperature superconductor and resistive heat load from copper coils will be too high on cryogenic system. HTS coils also allow much higher current density and significant reduction in size as compared to copper coils. Hence HTS solenoid provide a unique and technically superior solution. The use of a HTS solenoid with superconducting cavity offers a unique option as it can be placed in a …
Date:
March 28, 2011
Creator:
Anerella, M.; Ben-Zvi, Ilan; Kayran, D.; McIntyre, G.; Muratore, J.; Plate, S. et al.
Object Type:
Article
System:
The UNT Digital Library
[Email from Mike Anglin to Jack and George, August 28, 2011]
Email from Mike Anglin to Jack and George discussing possible people of interest in the Dallas gay history project on which Dallas Way worked.
Date:
August 28, 2011
Creator:
Anglin, Mike
Object Type:
Letter
System:
The UNT Digital Library
Dynamics of Human Adipose Lipid Turnover in Health and Metabolic Disease
None
Date:
July 28, 2011
Creator:
Arner, P.; Bernard, S.; Salehpour, M.; Possnert, G.; Leibl, J.; Steier, P. et al.
Object Type:
Article
System:
The UNT Digital Library
Slowly Varying Dilaton Cosmologies and Their Field Theory Duals
We consider a deformation of the AdS{sub 5} x S{sup 5} solution of IIB supergravity obtained by taking the boundary value of the dilaton to be time dependent. The time dependence is taken to be slowly varying on the AdS scale thereby introducing a small parameter {epsilon}. The boundary dilaton has a profile which asymptotes to a constant in the far past and future and attains a minimum value at intermediate times. We construct the sugra solution to first non-trivial order in {epsilon}, and find that it is smooth, horizon free, and asymptotically AdS{sub 5} x S{sup 5} in the far future. When the intermediate values of the dilaton becomes small enough the curvature becomes of order the string scale and the sugra approximation breaks down. The resulting dynamics is analysed in the dual SU(N) gauge theory on S{sup 3} with a time dependent coupling constant which varies slowly. When N{epsilon} << 1, we find that a quantum adiabatic approximation is applicable, and use it to argue that at late times the geometry becomes smooth AdS{sub 5} x S{sup 5} again. When N{epsilon} >> 1, we formulate a classical adiabatic perturbation theory based on coherent states which arises in the …
Date:
June 28, 2011
Creator:
Awad, Adel; Das, Sumit R.; Ghosh, Archisman; Oh, Jae-Hyuk & Trivedi, Sandip P.
Object Type:
Article
System:
The UNT Digital Library
Effects On Beam Alignment Due To Neutron-Irradiated CCD Images At The National Ignition Facility
The 192 laser beams in the National Ignition Facility (NIF) are automatically aligned to the target-chamber center using images obtained through charged coupled device (CCD) cameras. Several of these cameras are in and around the target chamber during an experiment. Current experiments for the National Ignition Campaign are attempting to achieve nuclear fusion. Neutron yields from these high energy fusion shots expose the alignment cameras to neutron radiation. The present work explores modeling and predicting laser alignment performance degradation due to neutron radiation effects, and demonstrates techniques to mitigate performance degradation. Camera performance models have been created based on the measured camera noise from the cumulative single-shot fluence at the camera location. We have found that the effect of the neutron-generated noise for all shots to date have been well within the alignment tolerance of half a pixel, and image processing techniques can be utilized to reduce the effect even further on the beam alignment.
Date:
February 28, 2011
Creator:
Awwal, A.; Manuel, A.; Datte, P. & Burkhart, S.
Object Type:
Article
System:
The UNT Digital Library
Constraining Proton Lifetime in SO(10) with Stabilized Doublet-Triplet Splitting
We present a class of realistic unified models based on supersymmetric SO(10) wherein issues related to natural doublet-triplet (DT) splitting are fully resolved. Using a minimal set of low dimensional Higgs fields which includes a single adjoint, we show that the Dimopoulos-Wilzcek mechanism for DT splitting can be made stable in the presence of all higher order operators without having pseudo-Goldstone bosons and flat directions. The {mu} term of order TeV is found to be naturally induced. A Z{sub 2}-assisted anomalous U(1){sub A} gauge symmetry plays a crucial role in achieving these results. The threshold corrections to {alpha}{sub 3}(M{sub Z}), somewhat surprisingly, are found to be controlled by only a few effective parameters. This leads to a very predictive scenario for proton decay. As a novel feature, we find an interesting correlation between the d = 6 (p {yields} e{sup +}{pi}{sup 0}) and d = 5 (p {yields} {bar {nu}}K{sup +}) decay amplitudes which allows us to derive a constrained upper limit on the inverse rate of the e{sup +}{pi}{sup 0} mode. Our results show that both modes should be observed with an improvement in the current sensitivity by about a factor of five to ten.
Date:
June 28, 2011
Creator:
Babu, K.S.; U., /Oklahoma State; Pati, Jogesh C.; /SLAC; Tavartkiladze, Zurab & /Oklahoma State U. /Tbilisi, Inst. Phys.
Object Type:
Article
System:
The UNT Digital Library
Beam losses due to abrupt crab cavity failures in the LHC
A major concern for the implementation of crab crossing in a future High-Luminosity LHC (HL-LHC) is machine protection in an event of a fast crab-cavity failure. Certain types of abrupt crab-cavity amplitude and phase changes are simulated to characterize the effect of failures on the beam and the resulting particle-loss signatures. The time-dependent beam loss distributions around the ring and particle trajectories obtained from the simulations allow for a first assessment of the resulting beam impact on LHC collimators and on sensitive components around the ring. Results for the nominal LHC lattice is presented.
Date:
March 28, 2011
Creator:
Baer, T.; Barranco, J.; Calaga, R.; Tomas, R.; Wenninger, B.; Yee, B. et al.
Object Type:
Article
System:
The UNT Digital Library
Booster main magnet power supply, present operation and potential future upgrades
The Brookhaven Booster Main Magnet Power Supply (MMPS) is a 24 pulse thyristor control supply, rated at 5500 Amps, +/-2000 Volts, or 3000 Amps, +/-6000 Volts. The power supply is fed directly from the power utility and the peak magnet power is 18 MWatts. This peak power is seen directly at the incoming ac line. This power supply has been in operation for the last 18 years. This paper will describe the present topology and operation of the power supply, the feedback control system and the different modes of operation of the power supply. Since the power supply has been in operation for the last 18 years, upgrading this power supply is essential. A new power supply topology has been studied where energy is stored in capacitor banks. DC to DC converters are used to convert the dc voltage stored in the capacitor banks to pulsed DC voltage into the magnet load. This enables the average incoming power from the ac line to be constant while the peak magnet power is pulsed to +/- 18 MWatts. Simulations and waveforms of this power supply will be presented.
Date:
March 28, 2011
Creator:
Bajon, E.; Bannon, M.; Marneris, I.; Danowski, G.; Sandberg, J. & Savatteri, S.
Object Type:
Article
System:
The UNT Digital Library
The Rambler (Fort Worth, Tex.), Vol. 94, No. 17, Ed. 1 Wednesday, September 28, 2011
Weekly student newspaper from Texas Wesleyan University in Fort Worth, Texas that includes campus and local news along with advertising.
Date:
September 28, 2011
Creator:
Banks, Shauna
Object Type:
Newspaper
System:
The Portal to Texas History
Simulations of NDCX-II Targets for Warm Dense Matter and Heavy Ion Fusion Physics
None
Date:
April 28, 2011
Creator:
Barnard, J. J.; Friedman, A.; Perkins, L. J.; Bieniosek, F. M.; Hay, M.; Henestroza, E. et al.
Object Type:
Article
System:
The UNT Digital Library
Study of Single and Coupled-Bunch Instabilities for NSLS-II
We study single and coupled-bunch instabilities for the NSLS-II storage ring with a recently developed parallel tracking code. For accurate modelling of the coupled-bunch instability, we investigate improvements to current point-bunch models to take into account finite bunch-size effects. Accurate modelling of single and coupled-bunch instabilities is of crucial importance for the machine performance of light sources such as NSLS-II, that provide high current beams. The complexity of the model consists in the accurate calculation of the impedance of the various components of the ring that can excite single and multibunch instabilities via short and long range wakefields. Moreover, a full account of the coupling between transverse and longitudinal dynamics must be taken into account to study effects such as chromaticity and Landau cavity effects. A parallel algorithm for the study of single and coupled-bunch instabilities has been implemented in a particle tracking code. The theoretical framework for single bunch instabilities is the same used in the code TRANFT, while for coupled-bunch instabilities a self-consistent algorithm has been implemented to allow the study of finite bunch-size effects and multibunch effects in arbitrary filling modes. In this paper we present numerical studies of the microwave instability for NSLS-II and discuss the …
Date:
March 28, 2011
Creator:
Bassi, G. & Blednykh, A.
Object Type:
Article
System:
The UNT Digital Library
Comparison of 1D and 2D CSR Models with Application to the FERMI@ELETTRA Bunch Compressors
We compare our 2D mean field (Vlasov-Maxwell) treatment of coherent synchrotron radiation (CSR) effects with 1D approximations of the CSR force which are commonly implemented in CSR codes. In our model we track particles in 4D phase space and calculate 2D forces [1]. The major cost in our calculation is the computation of the 2D force. To speed up the computation and improve 1D models we also investigate approximations to our exact 2D force. As an application, we present numerical results for the Fermi{at}Elettra first bunch compressor with the configuration described in [1].
Date:
March 28, 2011
Creator:
Bassi, G.; Ellison, J. A. & Heinemann, K.
Object Type:
Article
System:
The UNT Digital Library
Design and first cold test of BNL superconducting 112 MHz QWR for electron gun applications
Brookhaven National Laboratory and Niowave, Inc. have designed, fabricated, and performed the first cold test of a superconducting 112 MHz quarter-wave resonator (QWR) for electron gun experiments. The first cold test of the QWR cryomodule has been completed at Niowave. The paper discusses the cryomodule design, presents the cold test results, and outline plans to upgrade the cryomodule for future experiments. A quarter-wave resonator concept of superconducting RF (SRF) electron gun was proposed at BNL for electron cooling ion/proton beams at RHIC. QWRs can be made sufficiently compact even at low RF frequencies (long wavelengths). The long wavelength allows to produce long electron bunches, thus minimizing space charge effects and enabling high bunch charge. Also, such guns should be suitable for experiments requiring high average current electron beams. A 112 MHz QWR gun was designed, fabricated, and cold-tested in collaboration between BNL and Niowave. This is the lowest frequency SRF gun ever tested successfully. In this paper we describe the gun design and fabrication, present the cold test results, and outline plans for the cryomodule upgrade for future experiments.
Date:
March 28, 2011
Creator:
Belomestnykh, S.; Ben-Zvi, Ilan; Boulware, C. H.; Chang, X.; Grimm, T. L.; Siegel, B. et al.
Object Type:
Article
System:
The UNT Digital Library
Nuclear Physics using NIF
The National Ignition Facility (NIF) is the world's premier inertial confinement fusion facility designed to achieve sustained thermonuclear burn (ignition) through the compression of hydrogen isotopic fuels to densities in excess of 10{sup 3} g/cm{sup 3} and temperatures in excess of 100 MK. These plasma conditions are very similar to those found in the cores of Asymptotic Giant Branch (AGB) stars where the s-process takes place, but with a neutron fluence per year 10{sup 4} times greater than a star. These conditions make NIF an excellent laboratory to measure s-process (n,{gamma}) cross sections in a stellar-like plasma for the first time. Starting in Fall 2009, NIF has been operating regularly with 2-4 shots being performed weekly. These experiments have allowed the first in situ calibration of the detectors and diagnostics needed to measure neutron capture, including solid debris collection and prompt {gamma}-ray detection. In this paper I will describe the NIF facility and capsule environment and present two approaches for measuring s-process neutron capture cross sections using NIF.
Date:
September 28, 2011
Creator:
Bernstein, L. A.; Bleuel, D. L.; Caggiano, J. A.; Cerjan, C.; Gostic, J.; Hatarik, R. et al.
Object Type:
Article
System:
The UNT Digital Library
Intelligence Issues for Congress
None
Date:
October 28, 2011
Creator:
Best, Richard A. Jr.
Object Type:
Report
System:
The UNT Digital Library
Intelligence Issues for Congress
None
Date:
April 28, 2011
Creator:
Best, Richard A. Jr.
Object Type:
Report
System:
The UNT Digital Library