Reduction of the uranium metallocene,[eta5-1,2,4-(Me3C)3C5H2]2UCl2 (1), Cp'2UCl2, in the presence of2,2'-bipyridyl and sodium naphthalene gives the dark green metallocenecomplex, Cp'2U(bipy) (6), which reacts with p-tolylazide orpyridine-N-oxide to give Cp'2U=N(p-tolyl) (7) or Cp'2U(O)(py) (8),respectively. The Lewis acid, BPh3, precipitates Ph3B(py) and gives thebase-free oxo, Cp'2UO (10), which crystallizes from pentane. Theoxometallocene 10 behaves as a nucleophile with Me3SiX reagents but itdoes not exhibit cycloaddition behavior with acetylenes, suggesting thatthe polar resonance structure, Cp'2U+-O- dominates the double bondresonance structure Cp'2U=O.

A multidimensional, mountain-scale, thermal-hydrologic (TH) numerical model is presented for investigating unsaturated flow behavior in response to decay heat from the radioactive waste repository in the Yucca Mountain unsaturated zone (UZ), Nevada. The model, consisting of both two-dimensional (2-D) and three-dimensional (3-D) representations of the UZ repository system, is based on the current repository design, drift layout, thermal loading scenario, and estimated current and future climate conditions. This mountain-scale TH model evaluates the coupled TH processes related to mountain-scale UZ flow. It also simulates the impact of radioactive waste heat release on the natural hydrogeological system, including heat-driven processes occurring near and far away from the emplacement tunnels or drifts. The model simulations predict thermally perturbed liquid saturation, gas- and liquid-phase fluxes, and water and rock temperature elevations, as well as the changes in water flux driven by evaporation/condensation processes and drainage between drifts. These simulations provide mountain-scale thermally perturbed flow fields for assessing the repository performance under thermal loading conditions.

The progress of multiple bunches of charged particles down the main L-band linacs of the ILC (International Linear Collider) can be disrupted by wakefields. These wakefields correspond to the electromagnetic fields excited in the accelerating cavities and have both long-range and short-range components. The horizontal and vertical modal components of the wakefield will be excited at slightly different frequencies (the dipole mode frequency degeneracy's are split) due to inevitable manufacturing errors. We simulate the progress of the ILC beam down the collider under the influence of these wakefields. In particular, we investigate the consequences on the final emittance dilution of the beam of coupling of the horizontal to the vertical motion of the beam.

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Originally the PEP-II injection kickers were powered by one power supply. Since the kicker magnets where not perfectly matched, the stored beam got excited by about 7% of the maximum kicker amplitude. This led to luminosity losses which were especially obvious for trickle injection when the detector is on for data taking. Therefore two independent power supplies with thyratrons in the tunnel next to the kicker magnet were installed. This also reduces the necessary power by about a factor of four since there are no long cables that have to be charged. The kickers are now independently adjustable to eliminate any non-closure of the kicker system and therefore excitation of the stored beam. Setup, commissioning and fine tuning of this system are discussed.

With the impending construction of the Linac Coherent Light Source (LCLS) [1] at SLAC, displacing the well used Final Focus Test Beam (FFTB) area, there is growing interest in developing a new test beam facility which makes use of the remaining 2/3 of the SLAC linac, and is available during LCLS operations. The success of the Sub-Picosecond Pulse Source (SPPS) [2] and the desire to preserve this capacity suggest a new beamline with similar or improved electron beam quality, including bunch length compression to 10 {micro}m. Beam availability during LCLS operations requires a new 1-km bypass beamline connecting the 2/3-point of the linac with, for example, the existing B-Line tunnel at the end of the linac. A second operating mode, with LCLS not running, is then available using the existing connection directly from the end of the linac to the B-line. This path would provide the highest beam quality at 30 GeV and also allow a third operational mode by deflecting a few of the very high-brightness 120-Hz, 14-GeV LCLS bunches at low rate (1-10 Hz) into the B-line. Additionally, linear collider research might also be carried out in a short final focus system at the end of the B-Line, …

We investigate the emittance dilution that occurs due to long range wakefields in the ILC (International Linear Collider) L-band linacs. In previous simulations we have focused upon the largest kick factors (proportional to the transverse fields which transversely kick the beam off axis) for the first three pass-bands. Here we supplement these calculations with an additional four bands. We include seven pass-bands in our simulations with the upper dipole frequencies extending a little higher than 4 GHz. Higher order dipole modes in the first three pass-bands are damped by carefully orientating higher order mode couplers at both ends of each cavity. Here we investigate the impact of upper band modes on the beam dynamics.

For an x-ray free-electron laser (FEL) such as the LCLS, the FEL gain signal is accompanied by spontaneous radiation with a significant power level. Detecting the weak FEL gain among the large spontaneous background in the early stage of the exponential growth or for a low quality electron beam is important in commissioning the FEL. In this paper, we describe a simple ''lock-in'' method of weak FEL gain detection, suggested by K. Robinson, accomplished by slowly modulating the laser power of a designated beam heater that controls the local energy spread of the electron beam. We present numerical modeling that shows the effectiveness of this method and discuss its implementation in the LCLS.

The recent astounding discoveries of ignition in single-walled carbon nanotubes (SWNTs) after exposure to an ordinary photographic flash, (1) other formulations of carbons containing noble metals, (2) and polyaniline nanofibers (3) prompted us to explore a possible further instigation of explosive materials. Here, we report that an ignition and initiation process, further leading to actual detonation, does occur for explosives in lax contact with carbon nanotubes that are prone to opto-thermal activity via a conventional flashbulb. Optical ignition and initiation of explosives could thus far only be accomplished through lasers, (4) with specific characteristic of high power, pulse length, wavelength, and a small target area that greatly inhibit their applications. Our results have the implication that explosives with opto-thermally active SWNTs formulations are new ideal candidates for remote optical triggering of safety apparatus such as the firing of bolts on space shuttles rockets and aircraft exit doors, and for controlled burning of explosives as actuators.

The performance of a free electron lasers (FEL) is affected when the electron beam energy varies alone the undulator as would be caused by vacuum pipe wakefields and/or when the undulator strength parameter is tapered in the small signal regime until FEL saturation. In this paper, we present a self-consistent theory of FELs with slowly-varying beam and undulator parameters. A general method is developed to apply the WKB approximation to the beam-radiation system by employing the adjoint eigenvector that is orthogonal to the eigenfunctions of the coupled Maxwell-Vlasov equations. This method may be useful for other slowly varying processes in beam dynamics.

Longitudinal phase space properties of a photoinjector beam are important in many areas of high-brightness beam applications such as bunch compression, transverse-to-longitudinal emittance exchange, and high-gain free-electron lasers. In this paper, we discuss both the rf and the space charge contributions to the uncorrelated energy spread of the beam generated from a laser-driven rf gun. We compare analytical expressions for the uncorrelated energy spread and the longitudinal emittance with numerical simulations and recent experimental results.

The performance of parallel Monte Carlo transport calculations which use both spatial and particle parallelism is increased by dynamically assigning processors to the most worked domains. Since he particle work load varies over the course of the simulation, this algorithm determines each cycle if dynamic load balancing would speed up the calculation. If load balancing is required, a small number of particle communications are initiated in order to achieve load balance. This method has decreased the parallel run time by more than a factor of three for certain criticality calculations.

The ion flux from vacuum arc cathode spots was measured in two vacuum arc systems. The first was a vacuum arc ion source which was modified allowing us to collect ions from arc plasma streaming through an anode mesh. The second discharge system essentially consisted of a cathode placed near the center of a spherically shaped mesh anode. In both systems, the ion current streaming through the mesh was measured by a biased collector. The mesh anodes had geometric transmittances of 60 percent and 72 percent, respectively, which were taken into account as correction factors. The ion current from different cathode materials was measured for 50-500 A of arc current. The ion current normalized by the arc current was found to depend on the cathode material, with values in the range from 5 percent to 19 percent. The normalized ion current is generally greater for elements of low cohesive energy. The ion erosion rates were determined from values of ion current and ion charge states, which were previously measured in the same ion source. The absolute ion erosion rates range from 16-173 mu g/C.

Development of the comprehensive codes used to study the boundary region of the DIII-D tokamak has been done in parallel with improvement of the diagnostics of this important region of the plasma. These codes have been used to interpret the diagnostic data and assist in design of improved divertor configurations. The development of codes used for analysis on DIII-D is described briefly. Model validation by comparing with the extensive DIII-D boundary region diagnostic data is also discussed.

To meet growing energy demands, energy efficiency, renewable energy, and on-site generation coupled with effective utilization of exhaust heat will all be required. Additional benefit can be achieved by integrating these distributed technologies into distributed energy resource (DER) systems (or microgrids). This research investigates a method of choosing economically optimal DER, expanding on prior studies at the Berkeley Lab using the DER design optimization program, the Distributed Energy Resources Customer Adoption Model (DER-CAM). DER-CAM finds the optimal combination of installed equipment from available DER technologies, given prevailing utility tariffs, site electrical and thermal loads, and a menu of available equipment. It provides a global optimization, albeit idealized, that shows how the site energy loads can be served at minimum cost by selection and operation of on-site generation, heat recovery, and cooling. Five prototype Japanese commercial buildings are examined and DER-CAM applied to select the economically optimal DER system for each. The five building types are office, hospital, hotel, retail, and sports facility. Based on the optimization results, energy and emission reductions are evaluated. Furthermore, a Japan-U.S. comparison study of policy, technology, and utility tariffs relevant to DER installation is presented. Significant decreases in fuel consumption, carbon emissions, and energy costs …

Understanding and predicting the impact response of explosives and propellants remains a challenging area in the energetic materials field. Efforts are underway at LLNL (and other laboratories) to apply modern diagnostic tools and computational analysis to move beyond the current level of imprecise approximations towards a predictive approach more closely based on fundamental understanding of the relevant mechanisms. In this paper we will discuss a set of underlying mechanisms that govern the impact response of explosives and propellants: (a) mechanical insult (impact) leading to material damage and/or direct ignition; (b) ignition leading to flame spreading; (c) combustion being driven by flame spreading, perhaps in damaged materials; (d) combustion causing further material damage; (e) combustion leading to pressure build-up or relief; (f) pressure changes driving the rates of combustion and flame spread; (g) pressure buildup leading to structural response and damage, which causes many of the physical hazards. We will briefly discuss our approach to modeling up these mechanistic steps using ALE 3D, the LLNL hydrodynamic code with fully coupled chemistry, heat flow, mass transfer, and slow mechanical motion as well as hydrodynamic processes. We will identify the necessary material properties needed for our models, and will discuss our experimental efforts …