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An ultraviolet (UV) in-line Fraunhofer holography diagnostic has been developed for making high-resolution spatial measurements of ejecta particles traveling at many mm/μs. The diagnostic will be described and results from highexplosive shock-driven tin ejecta experiments will be presented. [ABSTRACT FROM AUTHOR]

Progress on the development of RF H- surface plasma source (SPS) with saddle antenna radio frequency (SA RF) discharge is considered. Several versions of new plasma generators with different antennas and magnetic field configurations were tested in the SNS small Test Stand. The efficiency of positive ion generation in plasma has been improved up to 0.18 A/cm2 per 1 kW of RF power at 13.56 MHz. A first prototype SA SPS with AlN chamber was installed in the SNS Test Stand that achieved current of H- ions up to 67 mA with an apparent efficiency of up to 1.6 mA/kW at RF frequency 2 MHz. A new version of the RF assisted triggering plasma source (TPS) has been designed, fabricated and tested. After cesiation emission of negative ions was increased from 1 mA to 5 mA with RF power 2.5 kW. [ABSTRACT FROM AUTHOR]

Parametric-resonance Ionization Cooling (PIC) is proposed as the final 6D cooling stage of a high-luminosity muon collider. Combining muon ionization cooling with parametric resonant dynamics should allow an order of magnitude smaller final equilibrium transverse beam emittances than conventional ionization cooling alone. In this scheme, a half-integer parametric resonance is induced in a cooling channel causing the beam to be naturally focused with the period of the channel's free oscillations. Thin absorbers placed at the focal points then cool the beam's angular divergence through the usual ionization cooling mechanism where each absorber is followed by RF cavities. A special continuous-field twin-helix magnetic channel with correlated behavior of the horizontal and vertical betatron motions and dispersion was developed for PIC. We present the results of modeling PIC in such a channel using GEANT4/G4beamline. We discuss the challenge of precise beam aberration control from one absorber to another over a wide angular spread. [ABSTRACT FROM AUTHOR]

Compact, high pressure, high current gas target features all metal construction and semi-automatic window assembly change. The unique aspect of this target is the domed-shaped window. The Havar alloy window is electron beam welded to a metal ring, thus forming one, interchangeable assembly. The window assembly is sealed by knife-edges locked by a pneumatic toggle allowing a quick, in situ window change. [ABSTRACT FROM AUTHOR]

A compact, fully automated solid target irradiation, handling and transfer system was developed for the 100Mo/99m Tc production; however, it can be used for any solid target material. All the target handling is fully automated. The target is pneumatically transferred to the irradiation station where it is removed from the carrier, placed in the irradiation chamber and the cooling water connected. At the end of irradiation the target is returned to the carrier and transferred to the processing hot cell where it is automatically placed in a distillation unit. 100 Mo targets are prepared by plasma spraying or laser cladding of the copper target. [ABSTRACT FROM AUTHOR]

The role of core excitation in the structure and dynamics of two-body halo nuclei is investigated. We present calculations for the resonant breakup of 11Be on protons at an incident energy of 63.7 MeV/nucleon, where core excitation effects were shown to be important. To describe the reaction, we use a recently developed extension of the DWBA formalism which incorporates these core excitation effects within the no-recoil approximation. The validity of the no-recoil approximation is also examined by comparing with DWBA calculations which take into account core recoil. In addition, calculations with two different continuum representations are presented and compared. [ABSTRACT FROM AUTHOR]

Nanostructured composites and nanowire arrays of traditional thermoelectrics like Bi, Bi1-xSbx and Bi2Te3 have metallic Rashba surface spin-orbit bands featuring high mobilities rivaling that of the bulk, for which topological insulator behavior has been proposed. Nearly pure surface electronic transport has been observed at low temperatures in Bi nanowires with diameter around the critical diameter, 50 nm, for the semimetal-to semiconductor transition. The surface contributes strongly to the thermopower, actually dominating for temperatures T < 100 K in these nanowires. The surface thermopower was found to be -1 T μV/K2, a value that is consistent with theory. We show that surface electronic transport together with boundary phonon scattering leads to enhanced thermoelectric performance at low temperatures of Bi nanowire arrays. We compare with bulk n-BiSb alloys, optimized CsBi4Te6 and optimized Bi2Te3. Surface dominated electronic transport can be expected in nanomaterials of the other traditional thermoelectrics. [ABSTRACT FROM AUTHOR]

Abell 115 contains two merging subclusters separated by about 900 kpc. The northern subcluster (hereafter, A115-N) contains a bright central galaxy that hosts the radio source 3C28 which has a remarkable morphology. Although there is no detectable active nucleus, two prominent jets connect to a pair of radio lobes, each of which exhibits a radio tail. We combine Chandra X-ray and VLA radio observations to study the gas motions in and around A115-N. We use the Chandra data to estimate the velocity of A115-N with respect to the ambient intracluster medium as well as the velocity of the gas within the subcluster A115-N. We suggest that the motion of A115-N through the cluster induces counter-rotating vortices in the subcluster gas that explain the unique morphology of 3C28 with its two tails pointing in the direction of motion for A115-N. We compare the X-ray gas circulation time within A115-N with the timescale computed from the spectral aging of the radio-emitting plasma and discuss the implications of these observations for the lifetimes of radio sources in gaseous atmospheres. [ABSTRACT FROM AUTHOR]

Novel configurations of helical superconducting magnets for muon beam 6D phase space cooling channels and demonstration experiments are being designed at Fermilab. Operating as needed for the beam cooling in a cryogenic environment, the helical solenoid generates longitudinal and transverse magnetic fields; meanwhile, large Lorentz forces are produced, so rigid coil support structures need to be designed. A short model of a helical solenoid (HS), consisting of four coils and supporting structures, was designed, built and tested at Fermilab. The magnetic and mechanical designs were analyzed using TOSCA and ANSYS. The supporting structures were fabricated and assembled using SSC NbTi cable. Strain gauges were utilized to monitor the deformation of the structures due to both thermal contraction and Lorentz forces. The superconducting coils were trained during the test. The model should prove the design concept, fabrication technology, and the magnet system performance. [ABSTRACT FROM AUTHOR]

The Fermi Gamma-ray Space Telescope, formerly named GLAST, is a mission in low-Earth orbit to observe gamma rays from the cosmos in the broad energy range from 20 MeV to >300 GeV, with supporting observations of gamma-ray bursts from 8 keV to 30 MeV. The telescope far surpasses previous generations in its ability to detect and localize faint gamma-ray sources, as well as its ability to see 20% of the sky at any instant and scan the entire sky on a timescale of a few hours. With its recent launch on 11 June 2008, Fermi has opened a new and exciting window on a wide variety of exotic astrophysical objects, including pulsars, black holes, active galactic nuclei, and gamma-ray bursts, and it will enable new research on such topics as the origin and circulation of cosmic rays and searches for hypothetical new phenomena such as annihilation of supersymmetric dark matter. [ABSTRACT FROM AUTHOR]

We demonstrate how X-ray measurements of the amount and distribution of gas and metals in the intracluster medium (ICM) of galaxy groups and clusters can probe the impact and feedback history of active galactic nuclei (AGN) in the cluster members. Comparing such measurements for a sample of groups to existing results for more massive clusters and to the optical and radio properties of the group members, we explore the role and efficiency of AGN in central group galaxies in (pre)-heating, mixing, and ejecting material from group-sized halos. AGN feedback appears to be important for mixing ICM metals in the cores of groups and low-mass clusters at the present day. At higher redshift, AGN outflows have plausibly also played a vital role in establishing the observed shortfall of gas and metals in groups compared to massive clusters. [ABSTRACT FROM AUTHOR]

One-dimensional shocks can be generated by impacting flyer plates accelerated to terminal velocities by a confined laser-ablated plasma. Over the past few years, we have developed this capability with our facility-size laser, TRIDENT, capable of >=500 Joules at multi-microsecond pulse lengths to accelerate 1-D flyer plates, 8-mm diameter by 0.1–2 mm thick. Plates have been accelerated to terminal velocities of 100 to >=500 m/s, with full recovery of the flyer and target for post mortem metallography. By properly tailoring the laser temporal and spatial profile, the expanding confined plasma accelerates the plate away from the transparent sapphire substrate, and decouples the laser parameters from shock pressure profile resulting from the plate impact on a target. Since the flyer plate is in free flight on impact with the target, minimal collateral damage occurs to either. The experimental method to launch these plates to terminal velocity, ancillary diagnostics, and representative experimental data is presented. [ABSTRACT FROM AUTHOR]

Microstructural effects including material anisotropy, impurities, grain size, and texture alter a material's response to dynamic loading through wave front dispersion and inelastic processes. The spatial variations created by these effects are a challenge for inertial confinement fusion (ICF) as they may seed instabilities, which could reduce thermonuclear yield, if not controlled through material processing. To this end, laser-driven confined shock experiments have been conducted on Be to characterize its dynamic strength properties and usefulness as an ICF ablator. Disks of Be 3 mm in diameter and 100 to 250 microns thick in the form of single crystal, rolled foil, and equal channel angular extruded were dynamically loaded to 100's kbar while the material behavior was measured with in-situ diagnostics. Clear two-wave structures were observed in free surface velocity records, providing a comparison of flow stress and other dynamic properties between Be types. [ABSTRACT FROM AUTHOR]

Ionization cooling, a method for shrinking the size of a muon beam, requires a low Z energy absorber, high field magnets, and high gradient radio frequency cavities. The use of high temperature superconductors (HTS) for the high field superconducting magnets is being considered to realize a helical muon cooling channel using hydrogen refrigeration. A test stand was set up at Fermilab to perform critical current (Ic) measurements of HTS wires under externally applied perpendicular and parallel fields at various temperatures. A description of the test setup and results on (Bi,Pb)2Sr2Ca2Cu3Ox (BSCCO-2223) tapes and Bi2Sr2CaCu2O8 (BSCCO-2212) round wires are presented. Finally, the engineering critical current density, JE, of HTS and Nb3Sn were compared in the application’s field and temperature range of interest. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Dynamic loading experiments are described using nanosecond scale laser pulses of 2 to 1000 GW/cm2 over a region 5 mm in diameter. The laser irradiance was tailored to generate shocks or quasi-isentropic compression. The experiments include novel diagnostic techniques with high temporal resolution: transient x-ray diffraction (TXD) and polarization-dependent reflectivity (ellipsometry). TXD uses a laser-produced plasma to form an x-ray source. These x rays are collimated by a pinhole to form a Bragg scattering source, which allowed powder lines to be detected from polycrystalline samples such as beryllium foils. Ellipsometry has been demonstrated with 50 ps resolution using the reflectance of a pulsed 660 nm laser from silicon and tin samples through lithium fluoride windows. Ellipsometry can indicate phase changes and potentially yields estimates of surface temperature via the dielectric conductivity. The combination of TXD and ellipsometry with VISAR measurements provides precision characterization of dynamic material properties at high pressures. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

A Linac Afterburner is proposed to raise the energy of the beam injected into the Fermilab Booster from 400 MeV to about 600 MeV, thereby alleviating the longitudinal and transverse space-charge effects at low energy that currently limit its performance. The primary motivation is to increase the integrated luminosity of the Tevatron Collider in Run II, but other future programs would also reap substantial benefits. The estimated cost is $23M. [ABSTRACT FROM AUTHOR]

The Trident laser at Los Alamos was used to impart known and controlled shocks in various materials by launching flyer plates or by irradiating the sample directly. Materials investigated include copper, gold, NiTi, SS316, and other metals and alloys. Tensile spall strength, elastic-plastic transition, phase boundaries, and equation of state can be determined with small samples. Using thin samples (0.1 - 1.0 mm thick) as targets, high pressure gradients can be generated with relatively low pressures, resulting in high tensile strain rates (10[sup 5] to 10[sup 8] s[sup -1]). Free surface and interface velocities are recorded with point- and line-imaging VISARs. The flexible spatial and temporal pulse profiles of Trident, coupled with the use of laser-launched flyer plates, provides capabilities which complement experiments conducted using gas guns and tensile bars. [ABSTRACT FROM AUTHOR]

We report here the current status of the Lick Observatory Supernova Search (LOSS) with the Katzman Automatic Imaging Telescope (KAIT). The progress on both the hardware and the software of the system is described, and we present a list of recent discoveries. LOSS is the world’s most successful search engine for nearby supernovae. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]