The new proton radioactivity {sup 155}Ta has been observed. It was produced via the p4n fusion evaporation channel using a {sup 58}Ni beam on a {sup 102}Pd target. The measured decay properties were: E{sub p} = (1765 {+-} 10) keV and t{sub 1/2} = (12{sub {minus}3}{sup +4}) {micro}s. Using the WKB approximation a spin and parity of J{sup {pi}} = 11/2{sup 2{minus}} and a spectroscopic factor of S{sub p}{sup exp} = 0.58{sub {minus}0.17}{sup +0.22} were determined.

Proton emission half-lives are calculated within the DWBA formalism for {sup 131}Eu and {sup 141}Ho assuming permanent quadruple deformation. The decay rates are consistent with a decay from either [411 3/2] or [413 5/2] Nilsson states for {sup 131}Eu and [523 7/2] Nilsson state for {sup 141}Ho.

The National Ignition Facility target chamber interior materials and target designs themselves have to be compatible with survival of the final-optics debris shields. To meet the planned maintenance and refinishing rate, the contamination of the debris shields cannot exceed about 1 nm equivalent thickness per shot of total material. This implies that the target mass must be limited to no more than 1 gram and the ablated mass released to the chamber from all other components must not exceed 3 grams. In addition, the targets themselves must either completely vaporize or send any minor amounts of shrapnel towards the chamber waist to prevent excessive cratering of the debris shields. The constraints on the first-wall ablation require that it be louvered to provide passive collection of remobilized contamination, because the expected target debris will remobilize at a rate fast enough to require cleaning every 3 weeks, about three times more frequent than possible with planned robotics. Furthermore, a comparison of ablatants from B{sub 4}C and stainless-steel louvers suggests that remobilization of target debris by x rays will be greater than of the base material in both cases, thereby reducing the performance advantage of clean B{sub 4}C over much-cheaper stainless steel. Neutronics …

For direct drive ICF, nonuniformities in laser illumination can seed ripples at the ablation front in a process called imprint. Such nonuniformities will grow during the capsule implosion and can penetrate the capsule shell impede ignition, or degrade burn. We have simulated imprint for a number of experiments on tile Nova laser. Results are in generally good agreement with experimental data. We leave also simulated imprint upon National Ignition Facility (NIF) direct drive ignition capsules. Imprint modulation amplitude comparable to the intrinsic surface finish of {approximately}40 nm is predicted for a laser bandwidth of 0.5 THz. Ablation front modulations experience growth factors up to several thousand, carrying modulation well into the nonlinear regime. Saturation modeling predicts that the shell should remain intact at the time of peak velocity, but penetration at earlier times appears more marginal.

We have studied numerically the evolution and decay of axion strings. These global defects decay mainly by axion emission and thus contribute to the cosmological axion energy density. The relative importance of this source relative to misalignment production of axions depends on the spectrum. Radiation spectra for various string loop configurations are presented. They support the contention that the string decay contribution is of the same order of magnitude as the contribution from misalignment.

Angular spread in the far-field radiation pattern of a cleaved dielectric waveguide is determined from the modal structure at the surface of the waveguide using the Smythe vector integral formulation. Essential features: First, a mode exists in the fiber that has no wavelength cutoff--the so-called HE{sub 11} mode. This mode arises when non-azimuthal angular dependence of the incoming radiation is present. Second, the energy flow from this hybrid mode fills the fiber face and is not annularly shaped as opposed to the symmetric TE and TM modes. Third, the HE{sub 11} mode is not polarization dependent in contrast to the TE and TM modes. Fourth, for small differences in the refractive indices between the core and cladding regions, only the HE{sub 11} mode will be supported until the next modes appear around 3.33{lambda}. At this point, three new modes can propagate and the model structure of the radiation becomes more complicated. Fifth, the far-field radiation pattern will have negligibly small angular dependence in the phases of the vector fields when only the lowest mode is present; the amplitude has an overall angular dependent form factor. Furthermore, when other modes are present (above 3.33{lambda}), the phase of the vector fields will …

Thomson scattering has been developed at the Nova laser facility as a direct and accurate diagnostic to characterize inertial confinement fusion plasmas. Measurements from methane-filled, ignition relevant hohlraums apply the theory for two ion species plasmas, which has been tested in separate open geometry experiments, to obtain electron and ion temperatures. The experimental data provide a benchmark for two-dimensional hydrodynamic simulations using LASNEX, which is presently in use to predict he performance of future megajoule laser- driven hohlraums of the National Ignition Facility (NIF). The data are consistent with modeling using significantly inhibited heat transport at the peak of the drive. Furthermore, we find that stagnating plasma regions on the hohlraum axis are well described by the calculations. The result implies that stagnation in gas-filled hohlraums occurs too late to directly affect the capsule implosion in ignition experiments.

High-resolution synchrotron based photoemission and x-ray absorption spectroscopy have been used to study the interaction of SO{sub 2} with a series of metals and oxides. The chemistry of SO{sub 2} on metal surfaces is rich. At low coverages, the molecule fully decomposes into atomic S and O. At large coverages, the formation of SO{sub 3} and SO{sub 4} takes place. The following sequence was found for the reactivity of the metals towards SO{sub 2}: Pt {approx} Rh < Ru < Mo << Zn, Sn, Cs. Alloying can be useful for reducing the chemical affinity of a metal for SO{sub 2} and controlling S poisoning. Pd atoms bonded to Rh and Pt atoms bonded to Sn interact weakly with SO{sub 2}. In general, SO{sub 2} mainly reacts with the O centers of metal oxides. SO{sub 4} is formed on CeO{sub 2} and SO{sub 3} on ZnO. On these systems there is no decomposition of SO{sub 2}. Dissociation of the molecule is observed after introducing a large amount of Ce{sup 3+} sites in ceria, or after depositing Cu or alkali metals on the oxide surfaces. These promote the catalytic activity of the oxides during the destruction of SO{sub 2}.

A 7.5 MHz RF cavity and power amplifier have been built and tested at Fermilab as part of the proton Driver Design Study. The project goal was to achieve the highest possible 7.5 MHz accelerating gradient at 15 Hz with a 50% duty cycle. To reduce beam loading effects, a low shunt impedance (500{Omega}) design was chosen. The 46 cm long single gap cavity uses 5 inductive cores, consisting of the nanocrystalline soft magnetic alloy Finemet, to achieve a peak accelerating voltage of 15 kV. The 95 cm OD tape wound cores have been cut in half to increase the cavity Q and are cooled from both sides using large water-cooled copper heat sinks. The prototype cavity has a shunt impedance of 550{Omega}, Q = 11, and is powered by a 200 kW cw cathode driven tetrode amplifier. Both cavity and amplifier designs are described. Results from recent cavity tests coalescing beam in the Fermilab Main Injector is also presented.

The Fermilab Main Injector can produce intense 120 GeV/c proton beams for fixed target experimentation. Two deflecting mode RF systems can be used to separate charged kaons from a momentum selected secondary beam, consisting of pions, kaons and protons, using a time of flight method. We present the RF design of a 3.9 GHz superconducting cavity which operates in the deflecting (TM110) pi-mode and the dependence of the RF parameters on the cavity shape, as determined with finite difference calculations. End cell compensation has been treated, providing cell-to-cell field flatness. First results from measurements on a prototype cavity are shown. We demonstrated that it is possible to tune the deflecting mode of a cell cavity with bead pull measurements. Effects relating the polarization of the modes are discussed.

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The heterogeneity of hydrogeologic properties at different scales may have different effects on flow and transport processes in a subsurface system. A model for the unsaturated zone of Yucca Mountain, Nevada, is developed to represent complex heterogeneity at two different scales: (1) layer scale corresponding to geologic layering and (2) local scale. The layer-scale hydrogeologic properties are obtained using inverse modeling, based on the available measurements collected from the Yucca Mountain site. Calibration results show a significant lateral and vertical variability in matrix and fracture properties. Hydrogeologic property distributions in a two-dimensional, vertical cross section of the site are generated by combining the average layer-scale matrix and fracture properties with local-scale perturbations generated using a stochastic simulation method. The unsaturated water flow and conservative (nonsorbing) tracer transport through the cross section are simulated for different sets of matrix and fracture property fields. Comparison of simulation results indicates that the local-scale heterogeneity of matrix and fracture properties has a considerable effect on unsaturated flow processes, leading to fast flow paths in fractures and the matrix. These paths shorten the travel time of a conservative tracer from the source (repository) horizon in the unsaturated zone to the water table for small fractions …

In this talk I describe how to discover or rule out the existence of W{prime} bosons at the CERN Large Hadron Collider as a function of arbitrary couplings and W{prime} masses. If W{prime} bosons are not found, I demonstrate the 95% confidence-level exclusions that can be reached for several classes of models. In particular, W{prime} bosons in the entire reasonable parameter space of Little Higgs models can be discovered or excluded in 1 year at the LHC.

We discuss the original idea of beam-beam compensation (BBC) in Section I, sequence of events in 2001-2002 and use of the Tevatron Electron Beam (TEL) for DC beam removal in Section II, (anti)proton lifetime improvement in Section III, experimental data on the BBC attempts in Section IV and, conclusively, Section V is devoted to discussion on important phenomena, needed improvements and future plans.

We describe Synergia, a hybrid code developed under the DOE SciDAC-supported Accelerator Simulation Program. The code combines and extends the existing accelerator modeling packages IMPACT and beamline/mxyzptlk. We discuss the design and implementation of Synergia, its performance on different architectures, and its potential applications.

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The Forward Detector upgrade project at CDF is designed to enhance the capabilities for studies of diffractive physics at the Tevatron during Run II. Studies of hard diffraction and very forward physics are some of the topics that can be addressed in the next few years at the Tevatron. The program for diffractive physics, including the detectors and their commissioning, is discussed here. All the detectors have been installed and are presently collecting data.

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Block copolymers are well known to undergo micro-phase separation. Typical domain sizes range from a few to about 100 nanometers. With use of OPV{sub n-}PEG{sub m} diblock copolymers, long nanofiber, short nanorod, and lamella morphologies have been observed. OPV is oligo(phenylenevinylene) and PEG is poly(ethyleneglycol). The OPV segment is photoluminescent as well as electroluminescent. The micrometer long OPV{sub 13-}PEG{sub 45} nanofiber consists of OPV{sub 13} inner core with radius of 5.2 nm, and PEG{sub 45} outer shell with overall fiber radius of 7.9 nm. The nanorod has similar core-shell composition but with much shorter length of {approx}100 nm. Lamella morphology consists of alternating OPV and PEG layers. The structural characterization and physical properties of these nanostructured materials and their implication are summarized.

The RESRAD-BIOTA code was developed through a partnership among U.S. Department of Energy, the U.S. Environmental Protection Agency, and the U.S. Nuclear Regulatory Commission. RESRAD-BIOTA provides a full spectrum of analysis capabilities, from cost effective conservative screening methods (using biota concentration guides) to realistic, organism-specific dose assessment. A beta version of the RESRAD-BIOTA code is currently available for use and testing. Continued coordination and partnerships with U.S. agencies and international organizations is providing opportunities for the inclusion of additional evaluation approaches and capabilities, such as (1) development of biota concentration guides for additional radionuclides, (2) additional flexibility for specifying and expanding organism options, (3) improvements to parameter datasets of environmental transfer factors, (4) inclusion of additional ''reference organism geometries'' (e.g., dose conversion factors for ellipsoids of appropriate size and shielding properties for different sized organisms, appropriate for specific ecosystem types), and (5) the capability to perform sensitivity and uncertainty analyses for calculated dose estimates.

A novel design of a wide-angle monochromatic x-ray beam shutter is discussed. The shutter is designed as a compact unit capable of providing users with the means of shutting off the beam in secondary beamlines that are at an angle to the primary beamline and to each other. The single-unit design used the fact that all the secondary beamlines will be closed at the same time. The main challenge was to fit the shutter in the limited space of the existing Advanced Photon Source IMMW-CAT hutch. Space limitations led to the change in position of the actuator subassembly as compared to the standard shutter design. Although the actuator subassembly is placed underneath the shutter, fail-safe shutting is achieved by placing tungsten blocks above the beam while the shutter is open and using gravity to close the shutter in case of pneumatic failure. Redundancy required by safety concerns was achieved by duplicating the tungsten block/actuator subunits. Tungsten blocks of uneven length were used to counteract the increase in the center-to-center distance among secondary beamlines due to their angular offset. A special support table was designed to facilitate assembly and adjustability of the shutter position in the available space. To provide a …

D-atom atomic resonance absorption spectrometric (ARAS) detection has been used to study the thermal decomposition of C{sub 2}D{sub 5}I to give C{sub 2}D{sub 5}-radicals in {approx}70% yield (924-1370 K). C{sub 2}D{sub 5} then decomposes to give C{sub 2}D{sub 4} + D effectively instantaneously on the time scale of the bimolecular kinetics experiments. The concurrent thermal decompositions of both C{sub 2}D{sub 5}I and CH{sub 3}I can then be used to prepare well-defined initial concentrations of both D-atoms and CH{sub 3}-radicals. Experiments were performed by observing absolute [D] depletion and [H] formation. The results were initially modeled with a 33 step mechanism; however, because of the high sensitivity for H- and/or D-detection, the mechanism could be reduced to four reactions, all of which are known except the exchange reaction, D + CH{sub 3} {yields} CH{sub 2}D + H. The rate constants were found to be temperature independent with k = (2.20 {+-} 0.22) x 10{sup -10} cm{sup 3} molecule{sup -1} s{sup -1} for 1294 {le} T {le} 1753 K. The present data have been combined with earlier lower temperature determinations, and the resultant database has been compared with unimolecular rate theory results. From theory, k = kk{sub {infinity}}<k{sub f{var_epsilon}}/(k{sub f{var_epsilon}} + k{sub …

The feasibility of using of a novel multi-pass absorption technique in combination with a shock tube for sensitive monitoring of free radicals for high-temperature kinetic studies was evaluated. The method was applied to study several elementary reactions of hydroxyl (OH) and methyl (CH{sub 3}) radicals.