How the U. S. Support Program (USSP) Provides Assistance to the IAEA Department of Safeguards (open access)

How the U. S. Support Program (USSP) Provides Assistance to the IAEA Department of Safeguards

N/A
Date: October 29, 2012
Creator: A., Diaz R.
System: The UNT Digital Library
Fermi Large Area Telescope Gamma-Ray Detection of the Radio Galaxy M87 (open access)

Fermi Large Area Telescope Gamma-Ray Detection of the Radio Galaxy M87

None
Date: March 29, 2012
Creator: Abdo, A. A.; /Naval Research Lab, Wash., D.C. /Federal City Coll.; Ackermann, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Ajello, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. et al.
System: The UNT Digital Library
Fermi Observations of TeV-Selected AGN (open access)

Fermi Observations of TeV-Selected AGN

None
Date: March 29, 2012
Creator: Abdo, A. A.; /Naval Research Lab, Wash., D.C. /Federal City Coll.; Ackermann, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Ajello, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. et al.
System: The UNT Digital Library
Fermi Large Area Telescope Observations of the Crab Pulsar and Nebula (open access)

Fermi Large Area Telescope Observations of the Crab Pulsar and Nebula

None
Date: March 29, 2012
Creator: Abdo, A. A.; Ackermann, M.; Ajello, M.; Atwood, W. B.; Axelsson, M.; Baldini, L. et al.
System: The UNT Digital Library
Fermi LAT Detection of Pulsed Gamma-Rays From the Vela-Like Pulsars PSR J1048-5832 and PSR J2229+6114 (open access)

Fermi LAT Detection of Pulsed Gamma-Rays From the Vela-Like Pulsars PSR J1048-5832 and PSR J2229+6114

We report the detection of {gamma}-ray pulsations ({ge}0.1 GeV) from PSR J2229+6114 and PSR J1048-5832, the latter having been detected as a low-significance pulsar by EGRET. Data in the {gamma}-ray band were acquired by the Large Area Telescope (LAT) aboard the Fermi Gamma-ray Space Telescope, while the radio rotational ephemerides used to fold the {gamma}-ray light curves were obtained using the Green Bank Telescope, the Lovell telescope at Jodrell Bank, and the Parkes Telescope. The two young radio pulsars, located within the error circles of the previously unidentified EGRET sources 3EG J1048-5840 and 3EG J2227+6122, present spin-down characteristics similar to the Vela pulsar. PSR J1048-5832 shows two sharp peaks at phases 0.15 {+-} 0.01 and 0.57 {+-} 0.01 relative to the radio pulse confirming the EGRET light curve, while PSR J2229+6114 presents a very broad peak at phase 0.49 {+-} 0.01. The {gamma}-ray spectra above 0.1 GeV of both pulsars are fit with power laws having exponential cutoffs near 3 GeV, leading to integral photon fluxes of (2.19 {+-} 0.22 {+-} 0.32) x 10{sup -7} cm{sup -2} s{sup -1} for PSR J1048-5832 and (3.77 {+-} 0.22 {+-} 0.44) x 10{sup -7} cm{sup -2} s{sup -1} for PSR J2229+6114. The first …
Date: March 29, 2012
Creator: Abdo, A. A.; Ackermann, M.; Ajello, M.; Atwood, W. B.; Axelsson, M.; Baldini, L. et al.
System: The UNT Digital Library
Fermi LAT Observations of LS 5039 (open access)

Fermi LAT Observations of LS 5039

The first results from observations of the high-mass X-ray binary LS 5039 using the Fermi Gamma-ray Space Telescope data between 2008 August and 2009 June are presented. Our results indicate variability that is consistent with the binary period, with the emission being modulated with a period of 3.903 {+-} 0.005 days; the first detection of this modulation at GeV energies. The light curve is characterized by a broad peak around superior conjunction in agreement with inverse Compton scattering models. The spectrum is represented by a power law with an exponential cutoff, yielding an overall flux (100 MeV-300 GeV) of 4.9 {+-} 0.5(stat) {+-} 1.8(syst) x 10{sup -7} photon cm{sup -2} s{sup -1}, with a cutoff at 2.1 {+-} 0.3(stat) {+-} 1.1(syst) GeV and photon index {Gamma} = 1.9 {+-} 0.1(stat) {+-} 0.3(syst). The spectrum is observed to vary with orbital phase, specifically between inferior and superior conjunction. We suggest that the presence of a cutoff in the spectrum may be indicative of magnetospheric emission similar to the emission seen in many pulsars by Fermi.
Date: March 29, 2012
Creator: Abdo, A. A.; Ackermann, M.; Ajello, M.; Atwood, W. B.; Axelsson, M.; Baldini, L. et al.
System: The UNT Digital Library
Multiwavelength Monitoring of the Enigmatic Narrow-Line Seyfert 1 PMN J0948 0022 in March-July 2009 (open access)

Multiwavelength Monitoring of the Enigmatic Narrow-Line Seyfert 1 PMN J0948 0022 in March-July 2009

Following the recent discovery of {gamma} rays from the radio-loud narrow-line Seyfert 1 galaxy PMN J0948+0022 (z = 0.5846), we started a multiwavelength campaign from radio to {gamma} rays, which was carried out between the end of 2009 March and the beginning of July. The source displayed activity at all the observed wavelengths: a general decreasing trend from optical to {gamma}-ray frequencies was followed by an increase of radio emission after less than two months from the peak of the {gamma}-ray emission. The largest flux change, about a factor of about 4, occurred in the X-ray band. The smallest was at ultraviolet and near-infrared frequencies, where the rate of the detected photons dropped by a factor 1.6-1.9. At optical wavelengths, where the sampling rate was the highest, it was possible to observe day scale variability, with flux variations up to a factor of about 3. The behavior of PMN J0948+0022 observed in this campaign and the calculated power carried out by its jet in the form of protons, electrons, radiation, and magnetic field are quite similar to that of blazars, specifically of flat-spectrum radio quasars. These results confirm the idea that radio-loud narrow-line Seyfert 1 galaxies host relativistic jets with …
Date: March 29, 2012
Creator: Abdo, A. A.; Ackermann, M.; Ajello, M.; Axelsson, M.; Baldini, L.; Ballet, J. et al.
System: The UNT Digital Library
Fermi Observations of High-Energy Gamma-Ray Emission From GRB 080825C (open access)

Fermi Observations of High-Energy Gamma-Ray Emission From GRB 080825C

None
Date: March 29, 2012
Creator: Abdo, A. A.; Ackermann, M.; Asano, K.; Atwood, W. B.; Axelsson, M.; Baldini, L. et al.
System: The UNT Digital Library
LCIO: A Persistency Framework and Event Data Model for HEP (open access)

LCIO: A Persistency Framework and Event Data Model for HEP

None
Date: November 29, 2012
Creator: Aplin, Steve; Engels, Jan; Gaede, Frank; Graf, Norman A.; Johnson, Tony & McCormick, Jeremy
System: The UNT Digital Library
Using The SLAC Two-Mile Accelerator for Powering an FEL (open access)

Using The SLAC Two-Mile Accelerator for Powering an FEL

A parameter survey is made, employing the recently developed 2D formalism for an FEL, of the characteristics of an FEL using the SLAC accelerator. Attention is focused upon a wavelength of 40 {angstrom} (the water window) and 1 {angstrom} case is also presented. They consider employing the SLAC linac with its present operating parameters and with improved parameters such as would be supplied by a new photo-cathode injector. They find that improved parameters are necessary, but that the parameters presently achieved with present-day photo-cathode guns are adequate to reach the water window.
Date: June 29, 2012
Creator: Barletta, W. A.; /LLNL, Livermore; Sessler, A. M.; /LBL, Berkeley; Yu, L. H. & /Brookhaven
System: The UNT Digital Library
Determination of the S-Wave Pi Pi Scattering Lengths From a Study of K - to Pi - Pi0 Pi0 Decays (open access)

Determination of the S-Wave Pi Pi Scattering Lengths From a Study of K - to Pi - Pi0 Pi0 Decays

We report the results from a study of the full sample of {approx}6.031 x 10{sup 7} K{sup {+-}} {yields} {pi}{sup {+-}}{pi}{sup 0}{pi}{sup 0} decays recorded by the NA48/2 experiment at the CERN SPS. As first observed in this experiment, the {pi}{sup 0}{pi}{sup 0} invariant mass (M{sub 00}) distribution shows a cusp-like anomaly in the region around M{sub 00} = 2m{sub +}, where m{sub +} is the charged pion mass. This anomaly has been interpreted as an effect due mainly to the final state charge exchange scattering process {pi}{sup +}{pi}{sup -} {yields} {pi}{sup 0}{pi}{sup 0} in K{sup {+-}} {yields} {pi}{sup {+-}}{pi}{sup +}{pi}{sup -} decay. Fits to the M{sub 00} distribution using two different theoretical formulations provide the presently most precise determination of a{sub 0} - a{sub 2}, the difference between the {pi}{pi} S-wave scattering lengths in the isospin I = 0 and I = 2 states. Higher-order {pi}{pi} rescattering terms, included in the two formulations, allow also an independent, though less precise, determination of a{sub 2}.
Date: March 29, 2012
Creator: Batley, J. R.; Culling, A. J.; Kalmus, G.; Lazzeroni, C.; Munday, D. J.; Slater, M. W. et al.
System: The UNT Digital Library
Optimal Donor Doping of Cd(Zn)Te Detector-Grade Crystals (open access)

Optimal Donor Doping of Cd(Zn)Te Detector-Grade Crystals

N/A
Date: October 29, 2012
Creator: Bolotnikov, A.; Fochuk, P.; Nakonechnyi, I.; Grill, R.; Kopach, O.; Nykoniuk, Ye. et al.
System: The UNT Digital Library
The Mass Distribution and Assembly of the Milky Way from the Properties of the Magellanic Clouds (open access)

The Mass Distribution and Assembly of the Milky Way from the Properties of the Magellanic Clouds

We present a new measurement of the mass of the Milky Way (MW) based on observed properties of its largest satellite galaxies, the Magellanic Clouds (MCs), and an assumed prior of a {Lambda}CDM universe. The large, high-resolution Bolshoi cosmological simulation of this universe provides a means to statistically sample the dynamical properties of bright satellite galaxies in a large population of dark matter halos. The observed properties of the MCs, including their circular velocity, distance from the center of the MW, and velocity within the MW halo, are used to evaluate the likelihood that a given halo would have each or all of these properties; the posterior probability distribution function (PDF) for any property of the MW system can thus be constructed. This method provides a constraint on the MW virial mass, 1.2{sup +0.7} - {sub 0.4}(stat.){sup +0.3} - {sub 0.3}(sys.) x 10{sup 12} M {circle_dot} (68% confidence), which is consistent with recent determinations that involve very different assumptions. In addition, we calculate the posterior PDF for the density profile of the MW and its satellite accretion history. Although typical satellites of 10{sup 12} M {circle_dot} halos are accreted over a wide range of epochs over the last 10 Gyr, …
Date: February 29, 2012
Creator: Busha, Michael T.; Marshall, Philip J.; Wechsler, Risa H.; Klypin, Anatoly & Primack, Joel
System: The UNT Digital Library
Pedestal Fueling Simulations with a Coupled Kinetic-kinetic Plasma-neutral Transport Code (open access)

Pedestal Fueling Simulations with a Coupled Kinetic-kinetic Plasma-neutral Transport Code

A Monte Carlo neutral transport routine, based on DEGAS2, has been coupled to the guiding center ion-electron-neutral neoclassical PIC code XGC0 to provide a realistic treatment of neutral atoms and molecules in the tokamak edge plasma. The DEGAS2 routine allows detailed atomic physics and plasma-material interaction processes to be incorporated into these simulations. The spatial pro le of the neutral particle source used in the DEGAS2 routine is determined from the uxes of XGC0 ions to the material surfaces. The kinetic-kinetic plasma-neutral transport capability is demonstrated with example pedestal fueling simulations.
Date: August 29, 2012
Creator: D.P. Stotler, C.S. Chang, S.H. Ku, J. Lang and G.Y. Park
System: The UNT Digital Library
Single Nanopores in Silicon Nitride Membranes with Applications to Viral Sensing (open access)

Single Nanopores in Silicon Nitride Membranes with Applications to Viral Sensing

While current viral sensing methods are extremely sensitive, there is still a need for platforms capable of detecting engineered viruses and being integrated into device architectures for point-of-care assessments. Nanopores could provide a single pathway to achieve these goals.
Date: March 29, 2012
Creator: Davenport, M. W.; Healy, K; Teslich, N; Letant, S E & Siwy, Z S
System: The UNT Digital Library
High-Resolution Methods for Phase Space Problems in Complex Geometries (open access)

High-Resolution Methods for Phase Space Problems in Complex Geometries

None
Date: February 29, 2012
Creator: Dorr, M. R.; Colella, P.; Hittinger, J. A.; Martin, D. F. & McCorquodale, P. W.
System: The UNT Digital Library
Status of the Dark Energy Survey Camera (DECam) Project (open access)

Status of the Dark Energy Survey Camera (DECam) Project

The Dark Energy Survey Collaboration has completed construction of the Dark Energy Camera (DECam), a 3 square degree, 570 Megapixel CCD camera which will be mounted on the Blanco 4-meter telescope at CTIO. DECam will be used to perform the 5000 sq. deg. Dark Energy Survey with 30% of the telescope time over a 5 year period. During the remainder of the time, and after the survey, DECam will be available as a community instrument. All components of DECam have been shipped to Chile and post-shipping checkout finished in Jan. 2012. Installation is in progress. A summary of lessons learned and an update of the performance of DECam and the status of the DECam installation and commissioning will be presented.
Date: June 29, 2012
Creator: Flaugher, Brenna L.; Abbott, Timothy M. C.; Angstadt, Robert; Annis, Jim; Antonik, Michelle, L.; Bailey, Jim et al.
System: The UNT Digital Library
A Compton-Vetoed Germanium Detector with Increased Sensitivity at Low Energies (open access)

A Compton-Vetoed Germanium Detector with Increased Sensitivity at Low Energies

The difficulty to directly detect plutonium in spent nuclear fuel due to the high Compton background of the fission products motivates the design of a Gamma detector with improved sensitivity at low energies. We have built such a detector by operating a thin high-purity Ge detector with a large scintillator Compton veto directly behind it. The Ge detector is thin to absorb just the low-energy Pu radiation of interest while minimizing Compton scattering of high energy radiation from the fission products. The subsequent scintillator is large so that forward scattered photons from the Ge detector interact in it at least once to provide an anti-coincidence veto for the Ge detector. For highest sensitivity, additional material in the line-of-sight is minimized, the radioactive sample is kept thin, and its radiation is collimated. We will discuss the instrument design, and demonstrate the feasibility of the approach with a prototype that employs two large CsI scintillator vetoes. Initial spectra of a thin Cs-137 calibration source show a background suppression of a factor of {approx}2.5 at {approx}100 keV, limited by an unexpectedly thick 4 mm dead layer in the Ge detector.
Date: March 29, 2012
Creator: Friedrich, S; Bates, C; Drury, O B; Burks, M & DiPrete, D
System: The UNT Digital Library
Dislocations and DefectStructure around Micro-indentations and Te Precipitates in CdTe (open access)

Dislocations and DefectStructure around Micro-indentations and Te Precipitates in CdTe

N/A
Date: October 29, 2012
Creator: G., Yang; Babentsov, V.; Sizov, F.; Franc, J.; Fochuk, P.; Bolotnikov, A. et al.
System: The UNT Digital Library
3DPDF: Open Source Solutions for Incorporating 3D Information in PDF Files (open access)

3DPDF: Open Source Solutions for Incorporating 3D Information in PDF Files

None
Date: November 29, 2012
Creator: Graf, Norman A.
System: The UNT Digital Library
mesh2gdml: from CAD to Geant4 (open access)

mesh2gdml: from CAD to Geant4

None
Date: November 29, 2012
Creator: Graf, Norman A.
System: The UNT Digital Library
lcsim: A Detector Response Simulation Toolkit (open access)

lcsim: A Detector Response Simulation Toolkit

None
Date: November 29, 2012
Creator: Graf, Norman A. & McCormick, Jeremy
System: The UNT Digital Library
Prototyping of the ILC Baseline Positron Target (open access)

Prototyping of the ILC Baseline Positron Target

The ILC positron system uses novel helical undulators to create a powerful photon beam from the main electron beam. This beam is passed through a titanium target to convert it into electron-positron pairs. The target is constructed as a 1 m diameter wheel spinning at 2000 RPM to smear the 1 ms ILC pulse train over 10 cm. A pulsed flux concentrating magnet is used to increase the positron capture efficiency. It is cooled to liquid nitrogen temperatures to maximize the flatness of the magnetic field over the 1 ms ILC pulse train. We report on prototyping effort on this system.
Date: February 29, 2012
Creator: Gronberg, J.; Brooksby, C.; Piggott, T.; Abbott, R.; Javedani, J. & Cook, E.
System: The UNT Digital Library
Gas-Phase Molecular Dynamics: High Resolution Spectroscopy and Collision Dynamics of Transient Species (open access)

Gas-Phase Molecular Dynamics: High Resolution Spectroscopy and Collision Dynamics of Transient Species

This research is carried out as part of the Gas-Phase Molecular Dynamics program in the Chemistry Department at Brookhaven National Laboratory. Chemical intermediates in the elementary gas-phase reactions involved in combustion chemistry are investigated by high resolution spectroscopic tools. Production, reaction, and energy transfer processes are investigated by transient, double resonance, polarization and saturation spectroscopies, with an emphasis on technique development and connection with theory, as well as specific molecular properties.
Date: May 29, 2012
Creator: Hall, G. E. & Goncharov, V.
System: The UNT Digital Library