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Constraints on Inelastic Dark Matter from XENON10 (open access)

Constraints on Inelastic Dark Matter from XENON10

It has been suggested that dark matter particles which scatter inelastically from detector target nuclei could explain the apparent incompatibility of the DAMA modulation signal (interpreted as evidence for particle dark matter) with the null results from CDMS-II and XENON10. Among the predictions of inelastically interacting dark matter are a suppression of low-energy events, and a population of nuclear recoil events at higher nuclear recoil equivalent energies. This is in stark contrast to the well-known expectation of a falling exponential spectrum for the case of elastic interactions. We present a new analysis of XENON10 dark matter search data extending to E{sub nr} = 75 keV nuclear recoil equivalent energy. Our results exclude a significant region of previously allowed parameter space in the model of inelastically interacting dark matter. In particular, it is found that dark matter particle masses m{sub x} {approx}> 150 GeV are disfavored.
Date: November 23, 2009
Creator: Angle, J; Aprile, E; Arneodo, F; Baudis, L; Bernstein, A; Bolozdynya, A et al.
System: The UNT Digital Library
CONTROL TESTING OF THE UK NATIONAL NUCLEAR LABORATORY'S RADBALL TECHNOLOGY AT SAVANNAH RIVER NATIONAL LABORATORY (open access)

CONTROL TESTING OF THE UK NATIONAL NUCLEAR LABORATORY'S RADBALL TECHNOLOGY AT SAVANNAH RIVER NATIONAL LABORATORY

The UK National Nuclear Laboratory (NNL) has developed a remote, non-electrical, radiation-mapping device known as RadBall (patent pending), which offers a means to locate and quantify radiation hazards and sources within contaminated areas of the nuclear industry. To date, the RadBall has been deployed in a number of technology trials in nuclear waste reprocessing plants at Sellafield in the UK. The trials have demonstrated the successful ability of the RadBall technology to be deployed and retrieved from active areas. The positive results from these initial deployment trials and the anticipated future potential of RadBall have led to the NNL partnering with the Savannah River National Laboratory (SRNL) to further underpin and strengthen the technical performance of the technology. RadBall consists of a colander-like outer shell that houses a radiation-sensitive polymer sphere. It has no power requirements and can be positioned in tight or hard-to reach places. The outer shell works to collimate radiation sources and those areas of the polymer sphere that are exposed react, becoming increasingly less transparent, in proportion to the absorbed dose. The polymer sphere is imaged in an optical-CT scanner which produces a high resolution 3D map of optical attenuation coefficients. Subsequent analysis of the optical …
Date: November 23, 2009
Creator: Farfan, E.
System: The UNT Digital Library
Iterative Dense Correspondence Correction Through Bundle Adjustment Feedback-Based Error Detection (open access)

Iterative Dense Correspondence Correction Through Bundle Adjustment Feedback-Based Error Detection

A novel method to detect and correct inaccuracies in a set of unconstrained dense correspondences between two images is presented. Starting with a robust, general-purpose dense correspondence algorithm, an initial pose estimate and dense 3D scene reconstruction are obtained and bundle-adjusted. Reprojection errors are then computed for each correspondence pair, which is used as a metric to distinguish high and low-error correspondences. An affine neighborhood-based coarse-to-fine iterative search algorithm is then applied only on the high-error correspondences to correct their positions. Such an error detection and correction mechanism is novel for unconstrained dense correspondences, for example not obtained through epipolar geometry-based guided matching. Results indicate that correspondences in regions with issues such as occlusions, repetitive patterns and moving objects can be identified and corrected, such that a more accurate set of dense correspondences results from the feedback-based process, as proven by more accurate pose and structure estimates.
Date: November 23, 2009
Creator: Hess-Flores, M A; Duchaineau, M A; Goldman, M J & Joy, K I
System: The UNT Digital Library
The Mission and Technology of a Gas Dynamic Trap Neutron Source for Fusion Material and Component Testing and Qualification (open access)

The Mission and Technology of a Gas Dynamic Trap Neutron Source for Fusion Material and Component Testing and Qualification

The successful operation (with {beta} {le} 60%, classical ions and electrons with Te = 250 eV) of the Gas Dynamic Trap (GDT) device at the Budker Institute of Nuclear Physics (BINP) in Novosibirsk, Russia, extrapolates to a 2 MW/m{sup 2} Dynamic Trap Neutron Source (DTNS), which burns only {approx}100 g of tritium per full power year. The DTNS has no serious physics, engineering, or technology obstacles; the extension of neutral beam lines to steady state can use demonstrated engineering; and it supports near-term tokamaks and volume neutron sources. The DTNS provides a neutron spectrum similar to that of ITER and satisfies the missions specified by the materials community to test fusion materials (listed as one of the top grand challenges for engineering in the 21st century by the U.S. National Academy of Engineering) and subcomponents (including tritium-breeding blankets) needed to construct DEMO. The DTNS could serve as the first Fusion Nuclear Science Facility (FNSF), called for by ReNeW, and could provide the data necessary for licensing subsequent FSNFs.
Date: November 23, 2009
Creator: Ivanov, A.; Kulcinski, J.; Molvik, A.; Ryutov, D.; Santarius, J.; Simonen, T. et al.
System: The UNT Digital Library
Water adsorption on alpha-Fe2O3(0001) at near ambient conditions (open access)

Water adsorption on alpha-Fe2O3(0001) at near ambient conditions

We have investigated hydroxylation and water adsorption on {alpha}-Fe{sub 2}O{sub 3}(0001) at water vapor pressures up to 2 Torr and temperatures ranging from 277 to 647 K (relative humidity (RH) {<=} 34%) using ambient-pressure x-ray photoelectron spectroscopy (XPS). Hydroxylation occurs at the very low RH of 1 x 10{sup -7}% and precedes the adsorption of molecular water. With increasing RH, the OH coverage increases up to one monolayer (ML) without any distinct threshold pressure. Depth profiling measurements showed that hydroxylation occurs only at the topmost surface under our experimental conditions. The onset of molecular water adsorption varies from {approx}2 x 10{sup -5} to {approx}4 x 10{sup -2}% RH depending on sample temperature and water vapor pressure. The coverage of water reaches I ML at {approx} 15% RH and increases to 1.5 ML at 34% RH.
Date: November 23, 2009
Creator: Yamamoto, Susumu; Kendelewicz, Tom; Newberg, John T.; Ketteler, Guido; Starr, David E.; Mysak, Erin R. et al.
System: The UNT Digital Library
X-ray Radiography and Scattering Diagnosis of Dense Shock-Compressed Matter (open access)

X-ray Radiography and Scattering Diagnosis of Dense Shock-Compressed Matter

Highly coupled Boron plasma has been probed by spectrally resolving an x-ray source scattered by the plasma. Electron density was inferred from the inelastic feature in the collective scattering regime. In addition, the mass density inferred from the non-collective X-ray Thomson scattering has been tested with independent characterization using X-ray radiography in the same drive condition. High-intensity laser produced K-alpha radiation was used as a backlighter for these dynamically compressed plasma experiments providing a high temporal resolution of the measurements. Mass density measurements from both methods are in good agreement. The measurements yield a compression of 1.3 in agreement with detailed radiation-hydrodynamic modeling. From the charge state measured in the non-collective regime and the electron density measured in the collective regime the mass density can then be constrained to 3.15 {+-} 0.16.
Date: November 23, 2009
Creator: Pape, S L; Neumayer, P; Fortmann, C; Doeppner, T; Davis, P; Krichter, A et al.
System: The UNT Digital Library