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Pump and probe damage testing for investigation of transient material modifications associated with laser damage in optical materials

Description: Laser-induced breakdown in the bulk of transparent dielectric materials is associated with the generation of extreme localized conditions of temperatures and pressures. In this work, we perform pump and probe damage testing experiments to investigate the evolution of transient absorption by the host material arising from modifications following confined laser energy deposition in fused silica and DKDP materials. Specifically, we measure the size of the damage sites observed in the region of spa… more
Date: October 18, 2007
Creator: Negres, R A; Feit, M D; DeMange, P; Bude, J D & Demos, S G
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

OPTICAL AND DYNAMIC PROPERTIES OF UNDOPED AND DOPED SEMICONDUCTOR NANOSTRUCTURES

Description: This chapter provides an overview of some recent research activities on the study of optical and dynamic properties of semiconductor nanomaterials. The emphasis is on unique aspects of these properties in nanostructures as compared to bulk materials. Linear, including absorption and luminescence, and nonlinear optical as well as dynamic properties of semiconductor nanoparticles are discussed with focus on their dependence on particle size, shape, and surface characteristics. Both doped and undo… more
Date: September 28, 2007
Creator: Grant, C D & Zhang, J Z
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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TiO2 Nanoparticles as a Soft X-ray Molecular Probe

Description: With the emergence of soft x-ray techniques for imaging cells, there is a pressing need to develop protein localization probes that can be unambiguously identified within the region of x-ray spectrum used for imaging. TiO2 nanocrystal colloids, which have a strong absorption cross-section within the "water-window" region of x-rays, areideally suited as soft x-ray microscopy probes. To demonstrate their efficacy, TiO2-streptavidin nanoconjugates were prepared and subsequently labeled microtubule… more
Date: June 30, 2007
Creator: Larabell, Carolyn; Ashcroft, Jared M.; Gu, Weiwei; Zhang, Tierui; Hughes, Steven M.; Hartman, Keith B. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Verifying the Cosmological Utility of Type Ia Supernovae:Implications of a Dispersion in the Ultraviolet Spectra

Description: We analyze the mean rest-frame ultraviolet (UV) spectrum ofType Ia Supernovae(SNe) and its dispersion using high signal-to-noiseKeck-I/LRIS-B spectroscopyfor a sample of 36 events at intermediateredshift (z=0.5) discoveredby the Canada-France-Hawaii TelescopeSupernova Legacy Survey (SNLS). Weintroduce a new method for removinghost galaxy contamination in our spectra,exploiting the comprehensivephotometric coverage of the SNLS SNe and theirhost galaxies, therebyproviding the first quantitative v… more
Date: November 2, 2007
Creator: Ellis, R. S.; Sullivan, M.; Nugent, P. E.; Howell, D. A.; Gal-Yam, A.; Astier, P. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Black ring deconstruction

Description: We present a sample microstate for a black ring in four and five dimensional language. The microstate consists of a black string microstate with an additional D6-brane. We show that with an appropriate choice of parameters the piece involving the black string microstate falls down a long AdS throat, whose M-theory lift is AdS_3 x S2. We wrap a spinning dipole M2-brane on the S2 in the probe approximation. In IIA, this corresponds to a dielectric D2-brane carrying only D0-charge. We conjecture t… more
Date: June 22, 2007
Creator: Gimon, Eric; Gimon, Eric G. & Levi, Thomas S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Evaluation of Polymer-Filler Interaction Characteristics by Force Microscopy

Description: Silicone polymers are frequently used as cushions and inserts between load bearing parts. In this capacity, they must act to position their associated parts and distribute mechanical force as appropriate. One type of failure is specific to silicones that are filled with high surface area particulates for purposes of tailoring the polymer compressive properties. Additives such as fumed silicon oxide are presumed to have a high degree of surface interaction with the polymer matrix, thus causing t… more
Date: April 23, 2007
Creator: Ratto, T & Saab, A
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Time Dependent CP Asymmetries and Branching RatioMeasurements in Charmless Three Body B Decays at BABAR

Description: In this work we presented measurements of CP violation and decay rates of B decays in final states not involving a charm quark in the final state. In particular, the time-dependent CP asymmetries of decays which proceed through b {yields} s elementary transition is a particularly sensitive probe of physics beyond the Standard Model. In fact, even if the precise measurements of CP conserving and CP violating processes show the success of the CKM picture of the flavour physics, the sector of b {y… more
Date: July 17, 2007
Creator: Di Marco, Emanuele & U., /Rome
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
open access

Measurements of CP asymmetries and branching fractions of two-body charmless decays of B^0 and B^0_s mesons

Description: The thesis is organized as follows: Chapter 1 describes the theoretical framework of non-leptonic B{sub (s)}{sup 0} {yields} H{sup +}h{prime}{sup -} decays, with a simple overview of the CP violation mechanism within the Standard Model and of the most used phenomenological approaches in the evaluation of strong interaction contributions. The chapter contains also a review of the theoretical expectations and the current experimental measurements along with a discussion about the importance of st… more
Date: December 1, 2007
Creator: Morello, Michael Joseph & /Pisa, Scuola Normale Superiore
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
open access

X-Ray Active Matrix Pixel Sensors Basedon J-FET Technology Developed for the Linac Coherent Light Source.

Description: An X-ray Active Matrix Pixel Sensor (XAMPS) is being developed for recording data for the X-ray Pump Probe experiment at the Linac Coherent Light Source (LCLS). Special attention has to be paid to some technological challenges that this design presents. New processes were developed and refined to address problems encountered during previous productions of XAMPS. The development of these critical steps and corresponding tests results are reported here.
Date: October 29, 2007
Creator: Carini, G. A.; Chen, W.; Li, Z.; Rehak, P. & Siddons, D. P.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Energy dependence of jet transport parameter and parton saturationin quark-gluon plasma

Description: We study the evolution and saturation of the gluondistribution function in the quark-gluon plasma as probed by apropagating parton and its effect on the computation of jet quenching ortransport parameter $\hat q $. For thermal partons, the saturation scale$Q2_s$ is found to be proportional to the Debye screening mass $\mu_D2$.For hard probes, evolution at small $x=Q2_s/6ET$ leads to jet energydependence of hat q. We study this dependence for both a conformal gaugetheory in weak and strong coupl… more
Date: June 24, 2007
Creator: Casalderrey-Solana, Jorge & Wang, Xin-Nian
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

GENERATION OF SUBPICOSECOND X-RAY PULSES IN STORAGE RINGS

Description: Supicosecond x-ray pulses are routinely produced at ALS,BESSY and SLS with slicing technique and used in pump-probe experimentswith controlled delay between laser pump pulses and x-ray probe pulses.New development aiming for a production of a subpicosecond x-ray pulsesusing rf orbit deflection technique is under way at APS. Both techniqueswill be reviewed here.
Date: June 19, 2007
Creator: Zholents, Alexander A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

PDV Probe Alignment Technique

Description: This alignment technique was developed while performing heterodyne velocimetry measurements at LLNL. There are a few minor items needed, such as a white card with aperture in center, visible alignment laser, IR back reflection meter, and a microscope to view the bridge surface. The work was performed on KCP flyers that were 6 and 8 mils wide. The probes used were Oz Optics manufactured with focal distances of 42mm and 26mm. Both probes provide a spot size of approximately 80?m at 1550nm. The 42… more
Date: October 26, 2007
Creator: Whitworth, T L; May, C M & Strand, O T
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Design of an electro-optical sampling experiment at the AWA facility

Description: The free space electro-optical (EO) sampling technique is a powerful tool for analyzing the longitudinal charge density of an ultrashort e-beam. In this paper, we present (1) experimental results for a laser-based mock-up of the EO experiment [1] and (2) a design for a beam-based, single-shot, EO sampling experiment using the e-beam from the Argonne Wakefield Accelerator (AWA) RF photoinjector. For the mock-up, a tabletop terahertz experiment is conducted in the AWA laser room. The mock-up uses… more
Date: June 1, 2007
Creator: Ruan, J.; Edwards, H.; Tan, Cheng Yang; Thurman-Keup, R.; Scarpine, V.; /Fermilab et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Energetics of Multiple-Ion Species Hohlraum Plasmas

Description: A study of the laser-plasma interaction processes in multiple-ion species plasmas has been performed in plasmas that are created to emulate the plasma conditions in indirect drive inertial confinement fusion targets. Gas-filled hohlraums with densities of xe22/cc are heated to Te=3keV and backscattered laser light is measured by a suite of absolutely calibrated backscatter diagnostics. Ion Landau damping is increased by adding hydrogen to the CO2/CF4 gas fill. We find that the backscatter from … more
Date: November 5, 2007
Creator: Neumayer, P; Berger, R; Callahan, D; Divol, L; Froula, D; London, R et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Measurement of Transverse Single-Spin Asymmetries for Di-JetProduction in Proton-Proton Collisions at sqrt s = 200 GeV

Description: We report the first measurement of the opening angledistribution between pairs of jets produced in high-energy collisions oftransversely polarized protons. The measurement probes (Sivers)correlations between the transverse spin orientation of a proton and thetransverse momentum directions of its partons. With both beams polarized,the wide pseudorapidity (-1 leq eta leq +2) coverage for jets permitsseparation of Sivers functions for the valence and sea regions. Theresulting asymmetries are all c… more
Date: October 2, 2007
Creator: Abelev, B. I.; Adams, J.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A comparison of DNA damage probes in two HMEC lines with X-irradiation

Description: In this study, we investigated {gamma}H2AX{sup ser139} and 53BP1{sup ser25}, DNA damage pathway markers, to observe responses to radiation insult. Two Human Mammary Epithelial Cell (HMEC) lines were utilized to research the role of immortalization in DNA damage marker expression, HMEC HMT-3522 (S1) with an infinite lifespan, and a subtype of HMEC 184 (184V) with a finite lifespan. Cells were irradiated with 50 cGy X-rays, fixed with 4% paraformaldehyde after 1 hour repair at 37 C, and processed… more
Date: January 19, 2007
Creator: Wisnewski, Christy L.; Bjornstad, Kathleen A.; Rosen, ChristoperJ.; Chang, Polly Y. & Blakely, Eleanor A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Dynamics of Converging Laser-Created Plasmas in Semi-Cylindrical Cavities Studied using Soft X-Ray Laser Interferometry

Description: The evolution of dense aluminum and carbon plasmas produced by laser irradiation of 500 {micro}m diameter semi-cylindrical targets was studied using soft x-ray laser interferometry. Plasmas created heating the cavity walls with 120 picosecond duration optical laser pulses of {approx} 1 x 10{sup 12} W cm{sup -2} peak intensity were observed to expand and converge on axis to form a localized high density plasma region. Electron density maps were measured using a 46.9 nm wavelength tabletop capill… more
Date: September 19, 2007
Creator: Purvis, M. A.; Grava, J.; Filevich, J.; Marconi, M.; Dunn, J.; Moon, S. J. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Femtosecond Time-Delay X-Ray Holography

Description: X-ray free-electron lasers (XFELs) will produce photon pulses with a unique and desirable combination of properties. Their short X-ray wavelengths allow penetration into materials and the ability to probe structure at and below the nanometer scale. Their ultra-short duration gives information about this structure at the fundamental time-scales of atoms and molecules. The extreme intensity of the pulses will allow this information to be acquired in a single shot, so that these studies can be car… more
Date: October 24, 2007
Creator: Chapman, H N
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Michrochannel plate for position sensitive alpha particle detection

Description: This paper will describe the use of a microchannel plate (MCP) as the associated particle detector on a sealed tube neutron generator. The generator produces neutrons and associated alpha particles for use as a probe to locate and identify hidden explosives in associated particle imaging (API). The MCP measures the position in two dimensions and precise timing of the incident alpha particle, information which is then used to calculate the emission time and direction of the corresponding neutron… more
Date: August 31, 2007
Creator: Tinsley, Paul Hurley and James
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Plasma Interactions in Laser Irradiated Semi-Cylindrical Cavities Studied with Soft X-Ray Interferometry Using a Capillary Discharge Laser

Description: Soft x-ray interferometry was used to measure the evolution of dense converging plasmas created by laser irradiation of 500 {micro}m diameter semi-cylindrical carbon targets. Optical laser pulses with an intensity of {approx} 1 x 10{sup 12} W cm{sup -2} and 120 ps duration were used to heat the surface of the cavities. The dense plasma formed expands from the walls converging slightly off the semi-cylinder's axis, giving rise to a bright localized high density plasma region. A sequence of elect… more
Date: September 19, 2007
Creator: Purvis, M. A.; Grava, J.; Filevich, J.; Marconi, M.; Rocca, J. J.; Moon, S. J. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Examination of Scattering Volume Aligment in Thomson Scattering Off of a Shock Front in Argon

Description: Thomson scattering in argon gas successfully probed the region of plasma just behind the shock front. The instantaneous shock velocity can be inferred from the duration of the signal, taking into account the size and shape of the scattering volume. Possible misalignment of the probe beam and spectrometer slits greatly affects the size and shape of the scattering volume, and therefore affects the calculation of the instantaneous shock velocity.
Date: July 26, 2007
Creator: Reighard, A. B.; Froula, D. H.; Drake, R. P.; Ross, J. S. & Divol, L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A celestial gamma-ray foreground due to the albedo of small solar system bodies and a remote probe of the interstellar cosmic ray spectrum

Description: We calculate the {gamma}-ray albedo flux from cosmic-ray (CR) interactions with the solid rock and ice in Main Belt asteroids and Kuiper Belt objects (KBOs) using the Moon as a template. We show that the {gamma}-ray albedo for the Main Belt and Kuiper Belt strongly depends on the small-body mass spectrum of each system and may be detectable by the forthcoming Gamma Ray Large Area Space Telescope (GLAST). The orbits of the Main Belt asteroids and KBOs are distributed near the ecliptic, which pas… more
Date: December 17, 2007
Creator: Moskalenko, Igor V.; Porter, Troy A.; Digel, Seth W.; Michelson, Peter F. & Ormes, Jonathan F.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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The Ability of the United States Federal Radiological Monitoring and Assessment Center to Collect and Disseminate Environmental Measurements during Radiological Emergencies

Description: The Federal Radiological Monitoring and Assessment Center (FRMAC) is the United States’ response organization for radiological emergencies. The FRMAC is structured as an operations center and employs the combined resources of several federal agencies to respond to any disaster resulting in the release of radioactivity. The mission of the FRMAC is to support state and local authorities in the gathering of environmental data using an array of survey equipment ranging from alpha probes, beta/gamma… more
Date: April 30, 2007
Creator: Essex, Craig Marianno and James
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Final Technical Report: Effects of Changing Water and Nitrogen Inputs on a Mojave Desert Ecosystem

Description: In order to anticipate the effects of global change on ecosystem function, it is essential that predictive relationships be established linking ecosystem function to global change scenarios. The Mojave Desert is of considerable interest with respect to global change. It contains the driest habitats in North America, and thus most closely approximates the world’s great arid deserts. In order to examine the effects of climate and land use changes, in 2001 we established a long-term manipulative g… more
Date: November 30, 2007
Creator: Smith, Stanley, D.; Nowak, Robert S.; Fenstermaker, Lynn, F. & Young, Michael,H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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