In this paper, we report on gamma ray and thermal neutron detection with RbGd2Br7:Ce scintillators. RbGd2Br7:Ce (RGB) is a new scintillator material, which shows high light output (56,000 photons/MeV) and has a fast principal decay constant (45 ns) when doped with 10 percent Ce. These properties make RGB an attractive scintillator for g-ray detection. Also, due to the presence of Gd as a constituent, RGB has a high cross section for thermal neutron absorption and can achieve close to 100 percent stopping efficiency with 0.5 mm thick RGB crystals. Crystals of RGB with three different Ce concentrations (0.1, 5, and 10 percent) have been grown and their basic scintillation properties such as light output, decay time, and emission spectrum have been measured. In addition, high efficiency thermal neutron detection has been confirmed in our studies.

The photon plus missing energy signature is a primary handle on two important classes of theories. Theories with large extra dimensions predict the production of photons in association with Kaluza-Klein excitations of the graviton. In supersymmetric theories with superlight gravitinos, photons can be produced in association with gravitino pairs. The signatures for these two theories are compared, and it is found that they can be distinguished by studying the photon energy distributions and scaling of the cross section with center-of-mass energy. Both these methods fail, however, if there are six extra dimensions. In that case, additional phenomena predicted by the theories would be required to narrow down the underlying causes of the photon plus missing energy signal. We also study the ability of these measurements to determine the number of extra dimensions.

Low-power EM radar-like sensors have made it possible to measure properties of the human speech production system in real-time, without acoustic interference [1]. By combining these data with the corresponding acoustic signal, we've demonstrated an almost 10-fold bandwidth reduction in speech compression, compared to a standard 2.4 kbps LPC10 protocol used in the STU-III (Secure Terminal Unit, third generation) telephone. This paper describes a potential EM sensor/acoustic based vocoder implementation.

We present position sensitivity measurements obtained with one of the 32-fold segmented HPGe detectors from Michigan State University. These measurements were performed with a collimated beam of {sup 137}Cs gamma rays scattered by 90 degrees. This deposits 374 keV at a given location inside the crystal. A position resolution can be determined over many events by examining the digitally recorded pulse shapes on the 32 electrical contacts. If position resolution is adequate, gamma ray Compton camera imaging may be possible.

We have evaluated {sup 16}O neutron cross sections in the resolved resonance region with the multilevel Reich-Moore code SAMMY. Resonance parameters were determined by a consistent analysis, including both Doppler and resolution broadening effects. To properly treat the {alpha} particle exit channel, an algorithm to calculate charged particle penetrabilities and shifts was incorporated into SAMMY.

Prior laboratory corrosion studies along with experience at the black liquor gasifier in New Bern, North Carolina, clearly demonstrate that serious material problems exist with the gasifier's refractory lining. Mullite-based and alumina-based refractories used at the New Bern facility suffered significant degradation even though they reportedly performed adequately in smaller scale systems. Oak Ridge National Laboratory's involvement in the failure analysis, and the initial exploration of suitable replacement materials, led to the realization that a simple and reliable, complementary method for refractory screening was needed. The development of a laboratory test system and its suitability for simulating the environment of black liquor gasifiers was undertaken. Identification and characterization of corrosion products were used to evaluate the test system as a rapid screening tool for refractory performance and as a predictor of refractory lifetime. Results from the test systems and pl ants were qualitatively similar.

The United States Department of Energy (DOE) carries out a significant amount of transportation each year, including waste remediation activities at the sites for which it is responsible. In future years, the amount of material transported is expected to increase, and the costs of this transportation are expected to be large. To support the assessment of such costs, a cost-estimating model was developed in 1996, peer-reviewed against other available packaging and transportation cost data, and used to calculate the costs for a significant number of shipping campaigns of radioactive waste. This cost-estimating model, known as the Ten-year Plan Transportation Model (TEPTRAM), served as the cost-estimating model for radioactive material shipments in developing the DOE Office of Environmental Management's Ten Year Plan. The TEPTRAM model considered costs for recovery and processing of the wastes, packaging of the wastes for transport, carriage of the waste and a rough estimate of labor cost s associated with preparing and undertaking the shipments. At the user's direction, the model could also include the cost for DOE's interaction with its external stakeholders (e.g., state and local governments and tribal entities) and the cost associated with tracking and communication (e.g., use of the DOE TRANSCOM system). By …

Homology-directed repair (HDR) of DNA double-strand breaks (DSBs) is a well-established mechanism that contributes to the maintenance of genomic stability in rodent cells, and it has been assumed that HDR is of similar importance in the repair of DSBs in human cells. However, in addition to promoting genomic stability, some outcomes of homologous recombination can be deleterious, suggesting that factors exist to regulate HDR. We previously demonstrated that overexpression of BCL-2 or BCL-xL enhanced the frequency of x-ray-induced mutations involving the TK1 locus, including loss of heterozygosity (LOH) events presumed to arise by mitotic recombination. The present study was designed to test whether HDR is a prominent DSB repair pathway in human cells, and to directly determine whether ectopic expression of BCL-xL affects HDR. We used the B-lymphoblastoid cell line TK6, which expresses wild-type TP53 and resembles normal lymphocytes in undergoing apoptosis following! genotoxic stress. U sing isogenic derivatives of TK6 cells (TK6-neo, TK6-bcl-xL), we find that a DSB in an integrated HDR reporter stimulates gene conversion 40-50-fold in TK6-neo cells, demonstrating that a DSB can be efficiently repaired by gene conversion in human cells. Significantly, DSB-induced gene conversion events are 3- to 4-fold more frequent in BCL-xL overexpressing cells. …

Direct measurement of the coherence time of a high-intensity laser beam (600 ps, 10{sup 14} W.cm{sup -2}) after plasma propagation is achieved using a Michelson interferometer. Through plasma of interest for indirect-drive fusion (0.1 x n{sub c}, 1 mm long), a large decrease of the coherence time is observed, from 100 ps to {approx} 10 ps, induced by the interaction between the intense beam and the plasma. This decrease is even stronger as the light is scattered at larger angles from the initial beam angular distribution and as the plasma density is increased. The results coincide with trends observed in recent numerical simulations.

The Central Solenoid Model Coil (CSMC) was designed and built from 1993 to 1999 by an ITER collaboration between the US and Japan, with contributions from the European Union and the Russian Federation. The main goal of the project was to establish the superconducting magnet technology necessary for a large-scale fusion experimental reactor. Three heavily instrumented insert coils were built to cover a wide operational space for testing. The CS Insert, built by Japan, was tested in April-August of 2000. The TF Insert, built by Russian Federation, will be tested in the fall of 2001. The NbAl Insert, built by Japan, will be tested in 2002. The testing takes place in the CSMC Test Facility at the Japan Atomic Energy Research Institute, Naka, Japan. The CSMC was charged successfully without training to its design current of 46 kA to produce 13 T in the magnet bore. The stored energy at 46 kA was 640 MJ. This paper presents the main results of the CSMC and the CS Insert testing--magnet critical parameters, ac losses, joint performance, quench characteristics and some results of the post-test analysis.

The interactions of methane with Bronsted acid sites in H-ZSM-5 were investigated both experimentally and theoretically. Diffuse reflectance infrared spectroscopy was used to acquire spectra for methane adsorbed on H-ZSM-5 at room temperature and at 77 K. Upon adsorption, the v1 and v3 vibrational bands of methane shift by -15 and -23 cm-1, respectively, and the vibrational band for OH groups associated with Bronsted acid sites shifts by -93 cm-1. Quantum chemical calculations conducted at the DFT level of theory with a 6-31g**++ basis set show that the observed shifts for methane are attributable to the effects of the electrostatic field created by the atoms of the zeolite. To represent the influence of the zeolite on the adsorbed methane correctly, it is essential to take into account the effects of the Madelung field, as well as the local effects of the acid center. The calculated shift in the vibrational frequency of the bridging OH group lies within the range observed experimentally. However, the quantitative agreement of the calculated and observed shift is not as good as that seen for the bands of CH4.

Thirty years ago, July 1, 1971, significant enhancement of negative ion emission from a gas discharge following an admixture of cesium was observed for the first time. This observation became the basis for the development of Surface Plasma Sources (SPS) for efficient production of negative ions from the interaction of plasma particles with electrodes on which adsorbed cesium reduced the surface work-function. The emission current density of negative ions increased rapidly from j {approximately} 10 mA/cm{sup 2} to 3.7 A/cm{sup 2} with a flat cathode and up to 8 A/cm{sup 2} with an optimized geometrical focusing in the long pulse SPS, and to 0.3 A/cm{sup 2} for DC SPS, recently increased up to 0.7 A/cm{sup 2}. Discovery of charge-exchange cooling helped decrease the negative ion temperature T below 1 eV, and increase brightness by many orders to a level compatible with the best proton sources, B = j/T> 1 A/cm{sup 2} eV. The combination of the SPS with charge-exchange injection improved large accelerators operation and has permitted beam accumulation up to space-charge limit and overcome this limit several times. The early SPS for accelerators have been in operation without modification for {approximately} 25 years. Advanced version of the SPS for …

Calcium and chloride are necessary cofactors for the proper function of the oxygen-evolving complex (OEC) of Photosystem II (PS II). Located in the thylakoid membranes of green plants, cyanobacteria and algae, PS II and the OEC catalyze the light-driven oxidation of water into dioxygen (released into the biosphere), protons and electrons for carbon fixation. The actual chemistry of water oxidation is performed by a cluster of four manganese atoms, along with the requisite cofactors Ca{sup 2+} and Cl{sup -}. While the Mn complex has been extensively studied by X-ray absorption techniques, comparatively less is known about the Ca{sup 2+} cofactor. The fewer number of studies on the Ca{sup 2+} cofactor have sometimes relied on substituting the native cofactor with strontium or other metals, and have stirred some debate about the structure of the binding site. past efforts using Mn EXAFS on Sr-substituted PSII are suggestive of a close link between the Mn cluster and Sr, within 3.5 {angstrom}. The most recent published study using Sr EXAFS on similar samples confirms this finding of a 3.5 {angstrom} distance between Mn and Sr. This finding was base3d on a second Fourier peak (R {approx} 3 {angstrom}) in the Sr EXAFS from functional …

A compact neutron generator based on D-D or D-T fusion reactions is being developed at the Lawrence Berkeley National Laboratory. The deuterium or tritium ions are produced in a radio-frequency (RF) driven multicusp plasma source. Seven beamlets are extracted and are accelerated to energy of 100 keV by means of a three-electrode electrostatic accelerator column. The ion beam then impinges on a titanium coated copper target where either the 2.4 MeV D-D or 14 MeV D-T neutrons are generated by fusion reaction. The development of the neutron tube is divided into three phases. First, the accelerator column is operated at hydrogen beam intensity of 15 mA. Second phase consists of deuterium beam runs at pulsed, low duty cycle 150 mA operation. The third phase consists of deuterium or tritium operation at 1.5 A beam current. Phase one is completed and the results of hydrogen beam testing are discussed. Low duty cycle 150 mA deuterium operation is being investigated. Neutron flux will be measured. Finally the phase three operation and the advance neutron generator designs are described.

A new proton injection kicker system is required for the Tevatron in the Run II era. The new system was designed to supply 1.25 kG-m into a magnetic aperture of 48 mm vertical x 71 mm horizontal x 5 m long with a 396 ns bunch spacing. The system was designed to be upgraded to 132 ns bunch spacing with additional pulse supplies. The design of the magnet incorporated some novel features in order to meet these requirements. These include adjustable bus spacing to set the inductance and balanced positive and negative high voltage buses. This system has been installed in the Tevatron.

A new proton injection kicker system is required for the Tevatron in the Run II era. The new system was designed to supply 1.25 kG-m into a magnetic aperture of 48 mm vertical x 71 mm horizontal x 5 m long with a 396 ns bunch spacing. The system was designed to be upgraded to 132 ns bunch spacing with additional pulse supplies. The system design tradeoffs needed to meet these goals is discussed. These include the system topology, the system impedance and the number of magnets. This system has been installed in the Tevatron.

The Fermilab Electron Cooling project involves interacting a 4.3 MeV, 0.5 A DC electron beam with 8.9 GeV/c antiprotons in the FNAL Recycler Ring. This interaction occurs through a 20-meter long cooling section consisting of 10 solenoid modules. This cooling process would lead to an increase in the Tevatron collider luminosity needed to support RunIIb parameters. There are several important engineering aspects of this cooling section including: solenoid design, vacuum system design, magnetic shielding, support system, and alignment methods. Details of the engineering issues related to each of these areas is discussed.

The Fermilab Electron Cooling Program requires a 20-m solenoidal region to interact 8-GeV antiprotons with an escorting beam of 4.3-MeV electrons to improve the phase-space quality of the antiproton beam. The solenoidal section with additional transport lines to take and return a 0.5-A electron beam from an electrostatic accelerator, for energy recovery, must be precisely aligned and adjusted. For the initial setup and study, and later testing of this line, a 12.4-keV H{sup {minus}} beam can be used to simulate the 4.3 MeV electron beam. For this purpose a high-brightness H{sup {minus}} ion source has been developed and tested. The source, a semiplanatron type, with a hollow cathode discharge and spherical cathode focusing of the emitted ions to the emission aperture has given an emission current density up to 0.7 A/cm{sup 2}. Continuous operation of 4 weeks has been demonstrated. Such an optimized source could have many applications for tandem accelerators, ion beam lithography and ion implantation.

A simple beam loading compensation system was installed for the Fermilab Main Injector Coalescing Cavities. This paper describes the design and implementation of the feedback system. These modifications improved the linear dynamic range of operation of the ferrite loaded cavity.

In the past year a spare NASA/GSFC Astro-E microcalorimeter has been installed, tested, and run successfully on the electron beam ions traps EBIT-I and EBIT-II at the Lawrence Livermore National Laboratory. The microcalorimeter complements crystal and grating spectrometers already part of the LLNL ebit program making it possible to measure a broad bandwidth ({approx}0.3-10 keV) with moderate resolution while simultaneously measuring a narrow bandwidth ({approx}0.7-1.3 keV) with high resolution. An overview of recent work, including measurements by the microcalorimeter of absolute excitation cross is presented. These results continue our effort to provide atomic data of high quality to be used as benchmarks of theoretical calculations and to be included in atomic data bases employed by spectral fitting packages used to interpret spectra obtained by XMM-Newton and the Chandra X-Ray Observatory.

This paper compares simulated versus recorded data for the RPM-SIM simulator, developed at the National Renewable Energy Laboratory's National Wind Technology Center. The simulator was used to study the system dynamics of a wind/diesel hybrid power system. We also provide information on newly developed simulator modules that will be released. The simulator performed extremely well, demonstrating flexibility in making modifications and including specialized modules required for problem solving. We also outline several possible applications for this tool.

Three high voltage modulators used during testing and operation of the Tevatron Electron Lens (TEL) at Fermilab will be described. Short high voltage (0 to {approximately} 20kV) pulses from these modulators vary the anode-cathode voltage of the TEL electron gun to control the magnitude of the electron beam current. The trio of modulators include a low repetition rate MOSFET-based pulser, a fast ionization device, and a high average power tetrode modulator. The characteristics of each device will be discussed and typical outputs from each type of modulator is shown.

Plasma immersion ion implantation (PIII) offers high throughput and efficiency in the synthesis of silicon-on-insulator (SOI) materials. In the separation by plasma implantation of oxygen (SPIMOX) process, the spatial and time variation of the sample temperature must be known and well controlled to ensure uniform buried oxide and silicon overlying layer thicknesses over the entire silicon wafer. In this paper, we describe a two-dimensional model and derive the temperature distribution on the silicon wafer with respect to time and other process parameters. Our results show laterally non-uniform heating by the incoming ions and the local temperature is influenced more by the sample voltage and thermal irradiation coefficient of the target than the pulse duration and plasma density. The model provides a simple and quick means to determine whether external heating will be needed to maintain the sample temperature at 600 C during the SPIMOX process.

The restructuring of regional electricity markets in the U.S. has been accompanied by numerous problems, including generation capacity shortages, transmission congestion, wholesale price volatility, and reduced system reliability. These problems have created significant new opportunities for technologies and business approaches that allow load serving entities and other aggregators, to control and manage the load patterns of their wholesale or retail end-users. These technologies and business approaches for manipulating end-user load shapes are known as Load Management or, more recently, Demand Responsive programs. Lawrence Berkeley National Laboratory (LBNL) is conducting case studies on innovative demand responsive programs and presents preliminary results for five case studies in this paper. These case studies illustrate the diversity of market participants and range of technologies and business approaches and focus on key program elements such as target markets, market segmentation and participation results; pricing scheme; dispatch and coordination; measurement, verification, and settlement; and operational results where available.