Search

Fourier transform ion cyclotron resonance laser microprobe mass spectrometry (FTICR LMMS) uses focused laser irradiation of solids with a spot of 5 [micro]m and a FTICR mass analyzer for local analysis with high mass resolution. A new ion source design has been developed to improve the extraction and transfer of ions generated in an external laser microprobe source. Calculations predicted trapping of ions initially emitted with angles up to 40[degrees] and 60[degrees] from the surface and from a distance of 1 mm above the sample, respectively. The analytical performances of the method have been verified on two sets of test samples. First, detection of chemisorbed benzotriazole on copper, average of two monolayers, has been shown with less sample consumption than typically required in static secondary ion mass spectrometry with a time-of-flight analyzer. Second, experiments on a thermal plate for offset printing have shown the feasibility of analysis and quantification of dyes embedded in a polymer matrix.

The advent of ultra-high-resolution mass spectrometry has revolutionized the ability of aquatic biogeochemists to examine molecular-level components of complex mixtures of organic matter. The ability to accurately assess the chemical composition, elemental formulas, or both of detected compounds is critical to these studies. Here we build on previous work that uses functional group relationships between compounds to extend elemental formulas of low molecular weight compounds to those of higher molecular weight. We propose an automated compound identification algorithm (CIA) for the analysis of ultra-high-resolution mass spectra of natural organic matter acquired by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. This approach is benchmarked with synthetic data sets of compounds cited in the literature. The sensitivity of our results is examined for different sources of error, and CIA is applied to two previously published data sets. We find that CIA works well for data sets with high mass accuracy (< 1 ppm) and can accurately determine the elemental formulas for > 95% of all compounds composed of C, H, O, and N. Data with lower mass accuracy must be accompanied with additional knowledge of chemical structure, composition, or both in order to yield accurate elemental formulas.

Measurements of the electron temperature radial profile [T.sub.e](r) have been performed on the Tokamak Chauffage Alfven Bresilien tokamak with high radial resolution, using an electron cyclotron emission radiometer. The temperature profile shows distinct peculiarities in discrete radial regions which can be associated with the presence of magnetic islands. A method is proposed here to determine the radial positions and widths of the magnetic islands based upon measurement of the Fitzpatrick kind, not completely flattened, radial profile of the electron temperature [T.sub.e](r). In combination with other well-known methods, the suggested methods can give additional possibilities for comparing experimental and theoretical results in the study of magnetic islands. Index Terms--Island width, magnetic island, radiometry, temperature profile, Tokamak.

An attempt is made to show that the saddle form of CTV (and other peripherally hexa-substituted TBCN) can be obtained by rapidly quenching a hot solution or the high-temperature melt to below room temperature. The saddle form of CTV was quantitatively separated from the quenched material by column chromatography.

Electron cyclotron emission (ECE) diagnostics have been developed in the large helical device (LHD). The ECE is transmitted over 80 m from the antenna to the spectrometer with the corrugated waveguide system, which has a low transmission loss (~30%). The polarization of ECE is identical for all frequencies, while the field angle varies from -40[degrees] to +30[degrees] on the ECE sight line. The ECE temperature measured by the Michelson, which is calibrated with a hot source, agrees well with Thomson scattering measurement in a wide range of the electron density. Magnetic island formation is investigated using the electron temperature profile measured with the Michelson. The radiometer is cross-calibrated to the Michelson and is employed for the study of fast phenomena, such as the sawtooth oscillation. Besides the normal ECE, tangential ECE is investigated in LHD in order to explore the potential of ECE diagnostics. Index Terms--Diagnostics, electron cyclotron emission (ECE), large helical device (LHD), microwave, plasma, temperature.

The operation of gyrodevices at cyclotron harmonics is very attractive because of the possibility to reduce the magnetic field requirement by s times, where s is the cyclotron harmonic number. In recent years, two methods of harmonic operation in multistage gyroamplifiers have been actively studied: operation at a given harmonic in all stages and operation in the frequency-multiplying regime when the input stage operates at a lower harmonic than the output one. The present paper is aimed at making a comparative analysis of these two schemes of operation. To do this, a simple analytical method is developed, which allows one to qualitatively describe saturation effects in both schemes and compare such performance characteristics as the efficiency, gain, and bandwidth in both schemes. The results are of interest for evaluating the pros and cons of both schemes. Index Terms--Cyclotron harmonics, frequency multiplication, gyroamplifiers, gyrotrons.

A low-pressure methane plasma is characterized and the results are compared with those obtained theoretically by considering the steady-state kinetics of the chemical processes present in a low-pressure plasma reactor, in order to elucidate the dominant reaction channels responsible for generation of the active precursors required for film growth. Mass spectrometry measurements of the gas phase indicate little variation in the plasma chemistry with increasing electron temperature.

Research involving design of a flux-coupled stack of 800 MeV isochronous cyclotrons is described. It is being designed for accelerator-driven thorium-cycle fission power.

The story of World War II project dedicated to electromagnetically separating uranium-235 from uranium-238 is described by a scientist participating in the project. The development and use of the 'calutron' to produce enriched uranium for the first atomic bomb that was used in warfare, and then to produce the full spectrum of separated uranium isotopes for uses in peacetime is discussed.

Timothy Koeth, a sophomore in physics built a 12-inch cyclotron. The stories behind every aspect of building the cyclotron are mentioned.

To prepare a variety of novel cyclotriphosphazene-based ligand systems with N and O donor sets, a straightforward solvent-free methodology is developed. With selected ligand constructs, a variety of metal complexes are synthesized.

The development of ruthenium-catalyzed intramolecular alkyne cyclotrimerizations of diynes and triynes is presented. It is concluded that the resulting ruthenabicyclo[3.2.0]-heptatriene intermediate produces competitive [2 + 2 + 2] cyclotrimerization products.

A study was conducted to investigate the enhancement of magneto-optic polar Kerr rotation over a broad range of optical frequencies by appropriate coupling of omega and omega(sub c), for fixed omega(sub p). The result found higher omega(sub p) values in higher Kerr rotation.

By taking advantage of recent developments in millimeter wave imaging technology, an electron cyclotron emission imaging (ECEI) instrument, capable of simultaneously measuring 128 channels of localized electron temperature over a two-dimensional (2-D) map in the poloidal plane, has been developed for the TEXTOR tokamak. Data from the new instrument, detailing the magnetohydrodynamic (MHD) activity associated with a sawtooth crash, is presented. Index Terms--Electron cyclotron emission, microwave diagnostics, sawtooth instability.