16346308
Fermilab's multi-petabyte scalable mass storage system
Fermilab provides a multi-petabyte scale mass storage system for high energy physics (HEP) experiments and other scientific endeavors. We describe the scalability aspects of the hardware and software architecture that were designed into the mass storage system to permit us to scale to multiple petabytes of storage capacity, manage tens of terabytes per day in data transfers, support hundreds of users, and maintain data integrity. We discuss in detail how we scale the system over time to meet the ever-increasing needs of the scientific community, and relate our experiences with many of the technical and economic issues related to scaling the system. Since the 2003 MSST conference, the experiments at Fermilab have generated more than 1.9 PB of additional data. We present results on how this system has scaled and performed for the Fermilab CDF and D0 Run II experiments as well as other HEP experiments and scientific endeavors.
59043366
Understanding polarized foreground from dust: Towards reliable measurements of CMB polarization
White Paper to the Cosmology and Fundamental Physics (GCT) Science Frontiers Panel of the Astro2010 Decadal Survey.
15552077
A cosmic microwave background radiation polarimeter using superconducting bearings
Measurements of the polarization of the cosmic microwave background (CMB) radiation are expected to significantly increase our understanding of the early universe. We present a design for a CMB polarimeter in which a cryogenically cooled half wave plate rotates by means of a high-temperature superconducting (HTS) bearing. The design is optimized for implementation in MAXIPOL, a balloon-borne CMB polarimeter. A prototype bearing, consisting of commercially available ring-shaped permanent magnet and an array of YBCO bulk HTS material, has been constructed. We measured the coefficient of friction as a function of several parameters including temperature between 15 and 80 K, rotation frequency between 0.3 and 3.5 Hz, levitation distance between 6 and 10 mm, and ambient pressure between 10/sup -7/ and 1 torr. The low rotational drag of the HTS bearing allows rotations for long periods of time with minimal input power and negligible wear and tear thus making this technology suitable for a future satellite mission.
15204601
The Magnetic Field Geometry in DR 21
We present broadband imaging polarimetry of DR 21 at 2.2 μm. Background stars shining through the lobes of the bipolar outflow show polarization aligned with the long axis of the outflow, indicating a magnetic field geometry oriented along the flow axis. There is no indication of a spiral or turbulent magnetic field geometry in the lobes. The polarization of stars in the central cluster has a different position angle than the lobes and is in good agreement with millimeter polarimetry. The nebulosity in the eastern lobe has moderate to high polarization, consistent with scattering of continuum light from the central cluster. We were unable to detect polarization of the nebulosity in the western lobe at the 4.2% (3 σ) level.
118411010
O/IR Polarimetry for the 2010 Decade (CGT): Science at the Edge, Sharp Tools for All
Andy Adamson B-G Andersson UKIRT, JAC, Hilo Stratospheric Observatory for Infrared Astronomy Karen Bjorkman Ryan Chornock Dan Clemens University of Toledo University of California, Berkeley Boston University James De Buizer Nicholas M. Elias II SOFIA, NASA Ames Universitat Heidelberg; MPIA Richard Ignace East Tennessee State University Terry Jay Jones University of Minnesota Alexander Lazarian Douglas C. Leonard University of Wisconsin San Diego State University Antonio Mario Magalhaes University of Sao Paulo, Brazil Marshall Perrin UCLA Claudia Vilega Rodrigues Inst. Nac. De Pesquisas Espaciais, Brazil Hiroko Shinnaga CalTech William Sparks Lifan Wang STScI Texas A&M University Lead Authors: Jennifer L. Hoffman Physics and Astronomy University of Denver 2112 E. Wesley Ave. Denver, CO 80208 (303) 871–2268 jennifer.hoffman@du.edu Dean C. Hines Space Science Institute New Mexico Office 405 Alamos Rd. Corrales, NM 87048 (505) 239-6762 hines@spacescience.edu star
121397034
Star formation in the Magellanic Clouds – III. IR observations of giant H II regions
114549808
Development of gas micro-strip chambers for radiation detection and tracking at high rates
117875651
Studies of P Wave Charm Meson Production at LEP with the OPAL Detector
119900272
The construction of the ATLAS semi-conductor tracker
Abstract The ATLAS (A Toroidal LHC ApparatuS) experiment at the Large Hadron Collider (LHC) at CERN has been designed to explore physics at the TeV energy scale and will be commissioned in 2007. In the innermost region of the experiment is a charged particle tracker, the Inner Detector of which the Semiconductor Tracker (SCT) is a major component. The SCT comprises a central barrel section enclosed by two endcaps (A and C). The construction of the major components of the ATLAS Semi-conductor tracker (SCT) is now nearing completion. Following a brief description of the design of the SCT, the logistics and organisation of the construction phase of the project are discussed. Central to the delivery of a high quality detector is the testing of large numbers of modules both during assembly and after they are mounted on their final support structures. The results of these tests for endcap C are presented showing that the electrical performance of the 988 modules to be installed in ATLAS is compatible with the specifications required.
108832091
The microdot gas avalanche chamber: an investigation of new geometries
Abstract The gains of the microstrip and microgap gas avalanche chambers are limited to below gains of 5 × 10 3 by geometrical and gas properties. In order to increase the maximum gain to greater than 2 × 10 4 a new detector geometry, the microdot, is proposed that can be produced at a standard silicon MOS microfabrication facility at similar cost to present microstrip gas detectors. In addition to charged particle tracking, the new geometry is also well suited to imaging applications. The operating characteristics of the new device have been investigated using a numerical simulation and a comparison with conventional strip geometries is presented. These results show that the microdot geometry reaches higher gas gains than the strip-like geometries, for the same set of electrode potentials, with a reduced cathode electric field enhancing operational stability.