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.

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 …

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.

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.

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.

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.

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 …

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 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.

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.

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.