ORCID Profile
0000-0002-6507-0689
Current Organisation
University of Missouri Columbia
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Publisher: Springer Science and Business Media LLC
Date: 1992
DOI: 10.1557/PROC-270-431
Abstract: Schottky diodes to be used for mechanical stress effect studies were fabricated using aluminum contacts to polycrystalline diamond thin films grown by a hot-filament assisted chemical vapor deposition process. Compressive stress was found to have a large effect on the forward biased current-voltage characteristics of the diode. At selected values of constant forward biased current, a linear relationship between voltage and stress, for stress less than 10 N was observed. The stress sensitivity of the diode was as high as 0.74 V/N at 1 mA forward bias. This study shows that polycrystalline diamond Schottky diodes are stress sensitive devices and have potential as mechanical sensors.
Publisher: Hindawi Limited
Date: 02-1987
DOI: 10.1017/S0263034600002548
Abstract: Sensitivity analysis is a powerful first-order mathematical technique that identifies the major reactions, the effects of errors in rate constants, pressure effects, and temperature effects in a plasma chemistry type model. Several methods of sensitivity analysis have been discussed in the literature. This paper describes the successful implementation of the state transition matrix method to the sensitivity analysis of a plasma chemistry model using both e-beams and ions for excitation. The ion excited plasma study is important to the field of nuclear-pumped lasers. This model examines 8 species and 37 reactions.
Publisher: Springer Science and Business Media LLC
Date: 30-01-2011
Publisher: Hindawi Limited
Date: 05-1984
DOI: 10.1017/S0263034600000768
Abstract: A novel method of utilizing fluorescence generated from the products of nuclear reactions offers the prospect of compact, high efficiency, multi-megajoule lasers. To overcome the problems associated with traditional laser (or energy converter)-fissile material interfaces, such as a uranium coating (low power density and low efficiency) or a gaseous uranium compound (low power density and deleterious effects on the laser kinetics and photon transport), a method suggested elsewhere of employing a reactor using a uranium aerosol fuel, interspersed with a fluorescer medium, is briefly reviewed. The charged particles produced by nuclear reactions in the fuel produce fluorescence in the core region of the reactor, through interactions with the fluorescer. This fluorescence can then be concentrated, to increase the effective power density in the laser medium, and used to drive a photolytic laser. One key issue in the above process is the charged particle spectrum from the fissile aerosol. These issues can be addressed theoretically based on the Dirac chord length distribution technique and an Arcen's function. The charged particle spectrum from a UO 2 coating has been generated and benchmarked with the experimental data of Kahn et al. , and Redmond et al. Agreement is generally good except near the end of the fission fragment tracks. The validity of this simple technique in approximating the rate of ion energy loss lends confidence to the generation of fission fragment spectra for other geometries (i.e. spherical in which transport efficiencies of over 60% appear achievable) using U, UO 2 and U 3 O 8 . Work is also extended to the case of B-10 in a variety of configurations which are frequently used in modern energy conversion experimental devices.
Publisher: Elsevier BV
Date: 09-2017
DOI: 10.1016/J.APRADISO.2017.05.005
Abstract: Nuclear batteries based on silicon carbide betavoltaic cells have been studied extensively in the literature. This paper describes an analysis of design parameters, which can be applied to a variety of materials, but is specific to silicon carbide. In order to optimize the interface between a beta source and silicon carbide p-n junction, it is important to account for the specific isotope, angular distribution of the beta particles from the source, the energy distribution of the source as well as the geometrical aspects of the interface between the source and the transducer. In this work, both the angular distribution and energy distribution of the beta particles are modeled using a thin planar beta source (e.g., H-3, Ni-63, S-35, Pm-147, Sr-90, and Y-90) with GEANT4. Previous studies of betavoltaics with various source isotopes have shown that Monte Carlo based codes such as MCNPX, GEANT4 and Penelope generate similar results. GEANT4 is chosen because it has important strengths for the treatment of electron energies below one keV and it is widely available. The model demonstrates the effects of angular distribution, the maximum energy of the beta particle and energy distribution of the beta source on the betavoltaic and it is useful in determining the spatial profile of the power deposition in the cell.
Publisher: Springer Science and Business Media LLC
Date: 08-1994
DOI: 10.1007/BF00414216
Publisher: Unpublished
Date: 1980
Publisher: Unpublished
Date: 1993
Publisher: Springer Science and Business Media LLC
Date: 05-1997
Abstract: Three natural type IIa diamond crystals were used for forced diffusion of boron. The diffusion was performed under bias otherwise with the same conditions. The boron diffusion coefficient in diamond was found to be 8.4 × 10 −15 and 4 × 10 −14 cm 2 /s at 1000 °C, depending on the direction of the electric field. The drift velocity of boron in diamond under 850 V at 1000 °C was found to be about 1.2 × 10 −8 cm/s.
Publisher: Elsevier BV
Date: 11-1996
Publisher: Hindawi Limited
Date: 20-11-2019
DOI: 10.1017/S0263034619000582
Abstract: A transport model for a transverse electron beam-pumped semiconductor laser has been developed. The model incorporates spatial dependencies of the power deposition from the beam as well as a three-dimensional model of the gain medium and the field intensity of the photons produced by stimulated emission in the oscillation cavity. This model accounts for spatial inhomogeneities and has been solved for a variety of pumping strengths. The model was developed so that it can be benchmarked with electron beam pumping. The dominant mechanisms for the production of electron–hole pair production within the semiconductor material is similar to the dominant mechanisms for the production of electron–hole production using ion beams. Thus, the model can be extended to fission fragment ion pumping of semiconductor lasers in order to model a nuclear-pumped laser/reactor system.
Publisher: Springer International Publishing
Date: 2016
Publisher: Office of Scientific and Technical Information (OSTI)
Date: 09-09-2003
DOI: 10.2172/815206
Publisher: Elsevier BV
Date: 07-2014
Publisher: Springer International Publishing
Date: 2016
Publisher: CRC Press
Date: 29-08-2002
Publisher: Unpublished
Date: 1992
Publisher: Elsevier BV
Date: 04-1993
Publisher: CRC Press
Date: 29-08-2002
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 08-2008
Publisher: AIP
Date: 2006
DOI: 10.1063/1.2405933
Publisher: Elsevier BV
Date: 1981
Publisher: Springer Science and Business Media LLC
Date: 2006
DOI: 10.1557/PROC-0929-II05-03
Abstract: The purpose of this paper is to report the experimental results of boron doping on 60-80 micron size diamond particles using Field Enhanced Diffusion with Optical activation (FEDOA) [1-5]. Diamond is a wide band gap material with unique combinations of optical, thermal, mechanical and electronic properties that can be useful for a number of applications including optoelectronic applications and micro sensor technology. The incorporation of boron into diamond has been proven to change its electrical properties and convert the diamond from insulator to a p-type semiconductor [3]. A promising technique for incorporation of impurities into diamond is FEDOA. FEDOA drives impurities into single crystalline diamond material and we have used this method in this study [5-7]. FEDOA uses a combination of thermal diffusion with bias plus thermal ionization and optical ionization I simultaneously. A modified version of FEDOA was implemented for the diffusion of boron in natural diamond type II/a powder of size 60-80 microns (Figure 1). The diamond powder was obtained from Microdiamant and has 99.9% purity. The boron powder used in the experiment was amorphous, 325 mesh 90 %(Assay), Mg (5%) nominal obtained from AESAR. A ratio of 3:1 Boron-Diamond mixture was used for the doping process. A heating element and a diamond-boron powder mixture holder were designed and incorporated in the FEDOA system. Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS) were used to study the diamond-doped morphology and identify impurities. Boron and hydrogen concentration results in the doped s les were studied using Prompt Gamma Neutron Activation Analysis (PGNAA) at the University of Missouri Research Reactor (MURR). Raman analysis of the treated s les was done as part of this work. The experimental results and analysis show that the s les were doped with boron. It was also found that s les with high boron concentration exhibited a high electrical conductivity. This work presents additional evidence that boron can be diffused into natural diamond powders. It also demonstrates that the FEDOA diffusion process is not only a powerful technique for the diffusion of impurities into wide band-gap materials in the form of single crystal plates, polycrystalline plate but also in a powder form with the modified FEDOA process.
Publisher: Unpublished
Date: 2001
Publisher: Elsevier BV
Date: 09-2018
DOI: 10.1016/J.APRADISO.2018.05.012
Abstract: This work demonstrates the development of diamond sensors with reliable contacts using a new metallization formula, which can operate under high-pressure gas environment. The metallization was created using thin film layers of titanium, platinum, gold and nickel deposited on a single crystal electronic grade CVD diamond chip. The contacts were 2 mm in diameter with thickness of 50/5/20/150 nm of Ti:Pt:Au:Ni. The optimum operating voltage of the sensor was determined from the current-voltage measurements. The sensor was calibrated with
Publisher: Hindawi Limited
Date: 02-1988
DOI: 10.1017/S0263034600003803
Abstract: Due to the low power density of pumping schemes for nuclear-pumped lasers prior to 1978, a method of utilizing the efficient production of narrow band fluorescence from excimers was developed. This method has since been referred to as a nuclear driven flashl . It is possible to achieve sufficient power densities, when combining the flashl with novel techniques of reactor/laser interfaces, to drive efficient, high power lasers directly with products from nuclear reactions.
Publisher: Elsevier BV
Date: 09-2018
DOI: 10.1016/J.APRADISO.2018.04.031
Abstract: This paper discusses the use of one of the safest isotopes known isotopes, Kr-85, as a candidate fuel source for deep space missions. This isotope comes from 0.286% of fission events. There is a vast quantity of Kr-85 stored in spent fuel and it is continually being produced by nuclear reactors. In using Kr-85 with a novel Dual Cycle Conversion System (DCCS) it is feasible to boost the system efficiency from 26% to 45% over a single cycle device while only increasing the system mass by less than 1%. The Kr-85 isotope is the ideal fuel for a Photon Intermediate Direct Energy Conversion (PIDEC) system. PIDEC is an excellent choice for the top cycle in a DCCS. In the top cycle, ionization and excitation of the Kr-85:Cl gas mixture (99% Kr and 1% Cl) from beta particles creates KrCl* excimer photons which are efficiently absorbed by diamond photovoltaic cells on the walls of the pressure vessels. The benefit of using the DCCS is that Kr-85 is capable of operating at high temperatures in the primary cycle and the residual heat can then be converted into electrical power in the bottom cycle which uses a Stirling Engine. The design of the DCCS begins with a spherical pressure vessel of radius 13.7 cm with 3.7 cm thick walls and is filled with a Kr-85:Cl gas mixture. The inner wall has diamond photovoltaic cells attached to it and there is a sapphire window between the diamond photovoltaic cells and the Kr-85:Cl gas mixture which shields the photovoltaic cells from beta particles. The DCCS without a gamma ray shield has specific power of 6.49 W/kg. A removable 6 cm thick tungsten shield is used to safely limit the radiation exposure levels of personnel. A shadow shield remains in the payload to protect the radiation sensitive components in the flight package. The estimated specific power of the unoptimized system design in this paper is about 2.33 W/kg. The specific power of an optimized system should be higher. The Kr-85 isotope is relatively safe because it will disperse quickly in case of an accident and if it enters the lungs there is no significant biological half-life.
Publisher: MDPI AG
Date: 26-03-2019
DOI: 10.3390/HEALTHCARE7010052
Abstract: Fuller’s earth spherical beads using chitosan as a binder were prepared for the removal of strontium ions from aqueous solution. The adsorbents were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which revealed the porous nature of the beads. The Brunauer–Emmett–Teller (BET) surface area of the beads was found to be 48.5 m2/g. The adsorption capacities of the beads were evaluated under both batch and dynamic conditions. The adsorption capacity was found to be ~29 mg/g of adsorbent at 298 K when the equilibrium concentration of strontium in the solution was 925 mg/L at pH 6.5. The X-ray photoelectron spectroscopy (XPS) data suggest that strontium uptake by the beads occurs mainly through an ion-exchange process. Kinetic data indicate that the sorption of strontium onto the beads follows anomalous diffusion. Thermodynamic data suggest that the ion-exchange of Sr2+ on the bead surface was feasible, spontaneous and endothermic in nature.
Publisher: Springer US
Date: 1986
Publisher: Springer US
Date: 1986
Publisher: Elsevier BV
Date: 09-2018
DOI: 10.1016/J.APRADISO.2018.04.028
Abstract: This paper demonstrates the ability of diamond sensors to respond to beta radiation. A Chemical Vapor Deposition (CVD) single crystal diamond was used in this work. The diamond crystal has a dimension of 4.5×4.5 by 0.5 mm thick. Metal contacts were fabricated on both sides of the diamond using titanium and palladium metals with thicknesses of 50 nm and 150 nm, respectively. The energy response of the diamond sensor was experimentally measured using three beta isotopes that cover the entire range of beta energy:
Publisher: Wiley
Date: 16-08-1992
Publisher: Springer US
Date: 1992
Publisher: Springer Netherlands
Date: 1997
Publisher: AIP Publishing
Date: 07-1982
DOI: 10.1063/1.1137114
Abstract: An intense effort to design, construct, and test a nuclear-pumping facility (NPF) has been completed at the University of Missouri-Columbia (UMC). The NPF has a flow capability similar to that of the now defunct Brookhaven Chemonuclear In-Pile Research Loop, plus the optical capability to monitor light output from the irradiation chamber. Both features make the UMC NPF a unique research loop usable for a wide variety of projects including radiation chemistry, fluorescence studies, photochemistry, dual media nuclear-pumped lasers, and direct nuclear-pumped lasers. Initial tests of the facility included a demonstration of 40.0 ft3/h flow rates (pump limited), and a spectral scan of N2 and He. The latter test represents a first effort in obtaining nuclear-pumped gas spectra from a high-power steady-state reactor such as the University of Missouri Research Reactor (MURR). Results indicate that observed spontaneous emission mainly comes from the first negative spectral series in N2+ (B2Σ+u →x2Σ+g) and from He*2 electronic transitions.
Publisher: Office of Scientific and Technical Information (OSTI)
Date: 08-1991
DOI: 10.2172/5003644
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 08-2005
Publisher: Unpublished
Date: 1989
Publisher: Office of Scientific and Technical Information (OSTI)
Date: 25-06-2009
DOI: 10.2172/958102
Publisher: Springer Science and Business Media LLC
Date: 1994
DOI: 10.1557/PROC-339-191
Abstract: We are reporting the first quantitative photoresponse characteristics of boron doped hot-filament CVD (HFCVD) diamond based Schottky diodes using semi-transparent aluminum contacts in the spectral range of 300–1050 nm. Quantum efficiencies, obtained without correction for surface reflection in the visible and near UV region, were between 5 % and 10% when the diodes were unbiased. Effect of reverse bias on the photoresponse was investigated at selected photon energies. Reverse biased diodes exhibit increasing photoresponse and ultimately saturation. Quantum efficiency as high as 30% was also obtained at 500 nm, when a reverse bias of over I volt was applied. The photoresponse mechanism of CVD diamond Schottky diodes is also discussed. A Schottky barrier height of 1.15 ± 0.02 eV for Al-HFCVD diamond contacts was determined using the d.c. photoelectric method.
Publisher: AIP Publishing
Date: 03-1989
DOI: 10.1063/1.1140437
Abstract: The Wien filter is an E×B deflecting analyzer with the electrostatic field perpendicular to the magnetostatic field. The twofold functions of the Wien filter are as an energy analyzer as well as a mass analyzer. It has very high resolution for paraxial charged-particle beams with V=E/B, the Wien velocity. Two Wien filters, a tilted-poles Wien filter, and a classical parallel-rectangular-poles Wien filter were built and tested for electrons up to 3.5 keV and protons beams of 200 eV. (The tilted-poles Wien filter is a new diagnostic developed by the authors.) The performance of the two is compared, and the tilted-poles Wien filter has superior resolution to the classical Wien filter. Both Wien filters appear to have features useful for high-temperature plasma diagnostics, including simultaneous measurement of energy and mass spectra, and high resolution.
Publisher: Elsevier BV
Date: 11-1995
Publisher: Springer Netherlands
Date: 1995
Publisher: AIP Publishing
Date: 07-1993
DOI: 10.1063/1.355198
Abstract: Novel low energy molecular implantation of trimethyl phosphite was used to make rectifying junctions with indium contacts on boron doped diamond grown on silicon substrates. Diamond growth utilized hot-filament enhanced chemical vapor deposition (HFCVD). To our knowledge, this is the first report of molecular implantation on diamond and the only implanted junction with HFCVD polycrystalline diamond on silicon as the starting material. The rectifying contacts have high current density in forward bias and exhibit linear inverse squared capacitance-voltage characteristics at high frequencies, unlike other rectifying diamond junctions.
Publisher: Unpublished
Date: 2015
Publisher: Springer Netherlands
Date: 1995
Publisher: Hindawi Limited
Date: 03-1993
DOI: 10.1017/S0263034600006923
Abstract: Diamond film technology has advanced to the point where electronic devices are now becoming feasible. In addition, diamond has outstanding mechanical properties. The energy given off in fusion reactions may be converted to a narrow-band light spectrum that can be absorbed by wide-bandgap photovoltaic cells to directly produce electricity. The properties of possible wide-bandgap photovoltaic cells are examined for the purpose of fusion energy conversion.
Publisher: IEEE
Publisher: AIP Publishing
Date: 04-1985
DOI: 10.1063/1.335504
Abstract: An experimental investigation of the atomic carbon laser’s energy storage was conducted with a rotating back mirror. The high rotational speed of the mirror allowed the laser cavity to be switched to a high Q configuration for various time delays after the discharge. This study, which combines results from experiments and computer simulations, revealed a short upper laser level lifetime of about 2 μsec. Thus, the lifetime of the upper laser state is too short to account for the delay observed (∼5 msec) in previous experiments on the atomic carbon nuclear-pumped laser.
Publisher: Springer US
Date: 1986
Publisher: Springer Science and Business Media LLC
Date: 1994
DOI: 10.1557/PROC-339-637
Abstract: Aluminum nitride (AlN) films were grown on silicon (Si) substrates by chemical vapor deposition (CVD). The films were characterized by scanning electron microscopy (SEM) and x-ray diffraction (XRD). The refractive index of the AlN films was determined by ellipsometry. Current-voltage and current-temperature characteristics were performed on metal-AlN-p + Si structures with Pt, Au and Al as metal electrodes. The characteristics showed that at high field and high temperature the carrier conduction mechanism in the film was dominated by Frenkel-Poole emission. The relative dielectric constant of the AlN films was estimated to be 9.66+0.3 from capacitance-voltage-frequency (C-V-f) measurements on Au-AlN-p + Si.
Publisher: Springer Science and Business Media LLC
Date: 07-10-2020
Publisher: Unpublished
Date: 2002
Publisher: Unpublished
Date: 1982
Publisher: Elsevier BV
Date: 05-1996
Publisher: AIP Publishing
Date: 06-1990
DOI: 10.1063/1.1141136
Abstract: The hyperbolic energy analyzer (HEA) is based on a novel diagnostic principle which uses a new type of electrostatic lens. The HEA has a pinhole aperture, a hyperbolic lens, and a long Faraday cup. The hyperboloid cones which make up the lens have a vertex angle of 70.53°. Each cone is held at a constant potential. The hyperbolic lens performs two functions: it focuses the ions in space and it selects the ion energy which is collected by the Faraday cup. The HEA measured electron and ion characteristics in the M4X (modified Missouri magnetic mirror experiment) and the results were confirmed with Langmuir probes and ion energy analyzers.
Publisher: Unpublished
Date: 1992
Publisher: Hindawi Limited
Date: 09-1995
DOI: 10.1017/S0263034600009484
Abstract: The use of nuclear radiation to excite lasers is examined from the perspective of nuclear flashl s. Nuclear driven flashl s can also be used as photon sources for photochemical and photovoltaic events. This can lead to the large scale production of chemicals and electricity.
Publisher: Springer US
Date: 1992
Publisher: Hindawi Limited
Date: 09-1998
DOI: 10.1017/S0263034600011319
Abstract: The concept and experimental results of a microwave-excited elliptical excimer l are presented in this paper. The plasma excimer photons are excited at one focus, and the absorber is placed at the second focus. Two elliptical microwave cavities with different eccentricities were tested to study the excitation and characteristics of such an elliptical excimer l . The results show that it can be a high-efficiency, narrow-band incoherent vacuum–ultraviolet (VUV)-to-near-infrared photon source. The potential applications of such an excimer l , especially with tunable vibronic solid-state and diamond thin film growth, are discussed.
Publisher: Unpublished
Date: 2001
Publisher: AIP Publishing
Date: 15-02-1993
DOI: 10.1063/1.353168
Abstract: Schottky diodes utilized for mechanical stress effect studies were fabricated using aluminum contacts to polycrystalline diamond thin films grown by a hot-filament-assisted chemical vapor deposition process. Compressive stress was found to have a large effect on the forward biased current-voltage characteristics of the diode, whereas the effect on the reverse biased characteristics was relatively small. This stress effect on the forward biased diamond Schottky diode was attributed to piezojunction and piezoresistance effects that dominated the diode current-voltage characteristics in the small and large bias regions, respectively. At a large constant forward bias current, a good linear relationship between output voltage and applied force was observed for force of less than 10 N, as predicted by the piezoresistance effect. The measured force sensitivity of the diode was as high as 0.75 V/N at 1 mA forward bias. Compared to either silicon or germanium junction diodes and tunnel diodes, polycrystalline diamond Schottky diodes not only are very stress sensitive but also have good linearity. This study shows polycrystalline diamond Schottky diodes have potential as mechanical sensors.
Publisher: Springer International Publishing
Date: 2016
Publisher: SPIE
Date: 04-1994
DOI: 10.1117/12.171755
Publisher: Springer Science and Business Media LLC
Date: 1994
DOI: 10.1557/PROC-339-643
Abstract: The content of bonded hydrogen in hot filament grown diamond films was determined by Fourier transform Infrared (FTIR) measurements before and after annealing. The quantity of bonded hydrogen was found to remain unchanged on annealing in diamond films with high amounts of microcrystalline diamond and amorphous carbon. The hydrogen content was found to decrease on annealing ∼9 times in diamond film of good crystalline quality. The change of the bulk hydrogen content did not seem to be linked to changes in resistivity of the s les.
Publisher: IEEE
Date: 2006
Publisher: Hindawi Limited
Date: 13-03-2018
DOI: 10.1002/ER.4053
Publisher: Unpublished
Date: 2013
Publisher: IEEE
Date: 2006
Publisher: Elsevier BV
Date: 03-1996
Publisher: Office of Scientific and Technical Information (OSTI)
Date: 11-1996
DOI: 10.2172/395669
Publisher: Elsevier BV
Date: 12-2017
DOI: 10.1016/J.APRADISO.2017.09.009
Abstract: Simulation of beta particle transport from a Ni-63 radioisotope in silicon using the Monte Carlo N-Particle (MCNP) transport code for monoenergetic beta particle average energy, monoenergetic beta particle maximum energy, and the more precise full beta energy spectrum of Ni-63 were demonstrated. The beta particle penetration depth and the shape of the energy deposition varied significantly for different transport approaches. A penetration depth of 2.25±0.25µm with a peak in energy deposition was found when using a monoenergetic beta particle average energy and a depth of 14.25±0.25µm with an exponential decrease in energy deposition was found when using a full beta energy spectrum and a 0° angular variation. For a 90° angular variation, i.e. an isotropic source, the penetration depth was decreased to 12.75±0.25µm and the backscattering coefficient increased to 0.46 with 30.55% of the beta energy escaping when using a full beta energy spectrum. Similarly, for a 0° angular variation and an isotropic source, an overprediction in the short circuit current and open circuit voltage solved by a simplified drift-diffusion model was observed when compared to experimental results from the literature. A good agreement in the results was found when self-absorption and isotope dilution in the source was considered. The self-absorption effect was 15% for a Ni-63 source with an activity of 0.25mCi. This effect increased to about 28.5% for a higher source activity of 1mCi due to an increase in thickness of the Ni-63 source. Source thicknesses of approximately 0.1µm and 0.4µm for these Ni-63 activities predicted about 15% and 28.5% self-absorption in the source, respectively, using MCNP simulations with an isotropic source. The modeling assumptions with different beta particle energy inputs, junction depth of the semiconductor, backscattering of beta particles, an isotropic beta source, and self-absorption of the radioisotope have significant impacts in betavoltaic battery design.
Publisher: Springer Science and Business Media LLC
Date: 13-03-2012
DOI: 10.1557/JMR.2012.50
Publisher: Elsevier BV
Date: 08-2018
Publisher: Elsevier BV
Date: 08-2014
Publisher: AIP Publishing
Date: 03-1991
DOI: 10.1063/1.1142079
Abstract: A radiation-hardened 60-channel x-ray tomography system has been developed to determine the two-dimensional distribution of x-ray emissivity from magnetically confined plasmas. In order to maximize their field of view, the diode arrays are mounted in re-entrant tubes inside the plasma chamber diagnostic ports. Metal foil vacuum windows serve as x-ray filters and permit the diodes and cables to be at atmospheric pressure. Pre lifiers are mounted at the outside end of the re-entrant tubes. The diode arrays and pre lifiers are protected from the harsh radiation environment by lead shielding. Image reconstruction is done using the harmonic expansion method or the linear algebraic method. For plasmas with some cylindrical symmetry the harmonic expansion method is superior, but for small discrete objects the Cartesian algebraic method is better. Preliminary data from the Missouri Magnetic Mirror plasma with electron cyclotron resonance heating show evidence of a hot electron ring.
Publisher: Elsevier BV
Date: 02-2015
Publisher: Office of Scientific and Technical Information (OSTI)
Date: 30-11-1993
DOI: 10.2172/10116322
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 12-1988
DOI: 10.1109/27.16555
Publisher: AIP
Date: 2006
DOI: 10.1063/1.2405993
Publisher: AIP Publishing
Date: 28-11-1994
DOI: 10.1063/1.112578
Abstract: Etching of hot-filament, chemical vapor deposited, diamond thin films utilizing low energy ion irradiation was investigated. The films used in this study were boron doped polycrystalline diamond, deposited on p-type (100) oriented silicon substrates. A low voltage dc corona discharge with an oxygen plasma was used to sputter etch the films. Surfaces were investigated by scanning electron microscopy and profilometry. Etch rates were approximately 500 Å/min, depending on the various processing conditions. Characteristics of In/diamond/Si Schottky diodes were used to evaluate the electrical properties of diamond surfaces with various treatments. Results indicate that plasma etching can significantly affect Schottky device characteristics.
Publisher: Unpublished
Date: 2001
Publisher: AIP Publishing
Date: 1990
DOI: 10.1063/1.1141943
Abstract: This article describes the design and operation of a system that produces a high-intensity proton beam. The system consists of a lithium proton source and an E×B stigmatic selector that produces a stigmatic proton beam at the mass focus. The protons are produced by bombarding electrons against a lithium surface. These protons are accelerated toward a special tilted-pole Wien filter (stigmatic selector), which eliminates astigmatism in the proton beam at the mass focus. The stigmatic E×B selector was also tested with electron beams, and their astigmatism was also eliminated. A classical E×B Wien filter with parallel poles (astigmatic selector) was used for comparison. The experimental spectral curves of both the proton current and the electron current, each using both types of selectors, are shown.
Publisher: Office of Scientific and Technical Information (OSTI)
Date: 15-01-2013
DOI: 10.2172/1059849
Publisher: SPIE
Date: 04-1994
DOI: 10.1117/12.171764
Publisher: SAGE Publications
Date: 07-2002
Publisher: Unpublished
Date: 2002
Publisher: IOP Publishing
Date: 10-2008
Publisher: Springer Science and Business Media LLC
Date: 1995
DOI: 10.1557/PROC-416-361
Abstract: The hydrogen content of free-standing polycrystalline CVD diamond s les was determined by Fourier Transform Infrared (FTIR) measurements and was quantified by a notched neutron spectrum technique. The latter measures the total bonded and unbonded hydrogen. The concentration of total hydrogen in these s les was of the same order of magnitude. The FTIR measurements, which are sensitive to the bonded hydrogen, indicated different hydrogen to diamond peak ratios.
Publisher: Unpublished
Date: 1982
Publisher: AIP Publishing
Date: 31-08-1992
DOI: 10.1063/1.107687
Abstract: Schottky diodes were fabricated using sputter deposited silver contacts to boron doped polycrystalline diamond thin films grown by a hot-filament chemical vapor deposition process with trimethyl borate as an in situ dopant source. High forward current density and a high forward-to-reverse current ratio were exhibited by these diodes. Current density-voltage and capacitance-voltage-frequency characteristics of these diodes are very similar to those of Schottky diodes fabricated using a single-crystal diamond substrate.
Publisher: Informa UK Limited
Date: 04-07-2007
Publisher: AIP Publishing
Date: 03-1997
DOI: 10.1063/1.364250
Abstract: Polycrystalline high quality freestanding 300-μm-thick diamond films were doped by diffusion of B and Li under electric bias in order to fabricate vertical p-n junctions. Circular contacts were obtained by high dose ion implantation of B and Li. The I–V characteristics were rectifying. When illuminated by deuterium l , an open circuit voltage was 2.6 eV. The shape of the I–V characteristic under illumination points to the existence of shunt and series resistances. The obtained structure is most probably a p-n junction with bad contacts.
Publisher: Springer Netherlands
Date: 2011
Publisher: Springer Netherlands
Date: 2011
Publisher: Elsevier BV
Date: 03-2012
Publisher: Springer Netherlands
Date: 2011
Publisher: AIP Publishing
Date: 1982
DOI: 10.1063/1.329912
Abstract: The use of volume sources, such as nuclear pumping, presents some unique features in the design of photolytically driven systems (e.g., lasers). In systems such as these, for ex le, a large power deposition is not necessary. However, certain restrictions, such as self-absorption, limit the ability of photolytically driven systems to scale by volume. A photon transport computer program was developed at the University of Missouri-Columbia to study these limitations. The development of this code is important, perhaps necessary, for the design of photolytically driven systems. With the aid of this code, a photolytically driven iodine laser was designed for utilization with a 3He nuclear-pumped system with a TRIGA reactor as the neutron source. Calculations predict a peak power output of 0.37 kW. Using the same design, it is also anticipated that the system can achieve a 14-kW output using a fast burst-type reactor neutron source, and a 0.65-kW peak output using 0.1 Torr of the alpha emitter radon-220 as part of the fill. The latter would represent a truly portable laser system.
Publisher: Springer Netherlands
Date: 2011
Publisher: AIP Publishing
Date: 06-1994
DOI: 10.1063/1.356591
Abstract: Pt2Si Schottky-barrier diodes were found to exhibit excellent photoresponse in the wavelength region of 116.4–221.4 nm when they were operated in the front illumination mode. Quantum efficiencies as high as 220% were achieved, depending on the substrate resistivity used and the Pt2Si film thickness.
Publisher: Springer Science and Business Media LLC
Date: 08-1995
Abstract: Diamond films have been grown by hot filament chemical vapor deposition (CVD) on mirror-polished positively biased Si substrates. Very smooth films a few micrometers thick were obtained in only 30 min. SEM, x-ray diffraction patterns, and Raman were used to characterize the films. Not only diamond but other carbon phases, were also detected. The initial structure showed a high density of defects and large stresses. Structural changes in time were found to occur with films apparently undergoing a phase transformation.
Publisher: SPIE
Date: 07-01-2004
DOI: 10.1117/12.504396
Publisher: Springer Netherlands
Date: 1995
Publisher: Springer Science and Business Media LLC
Date: 10-1995
Abstract: 10 B doped diamond films grown by hot filament chemical vapor deposition were neutron irradiated at moderately high fluence levels. The as-irradiated and annealed s les, along with an unirradiated s le, were analyzed using Raman spectroscopy and x-ray diffraction. It was found that a non-diamond amorphous phase was formed on irradiation. This phase transformed back to diamond on annealing. No graphite formation was observed. A comparison with nanodiamond powder was made. A similarity between irradiated diamond films and nanocrystalline diamond powder is discussed.
Publisher: Elsevier BV
Date: 02-2018
DOI: 10.1016/J.APRADISO.2017.11.026
Abstract: Radiation damage is a significant concern with both alphavoltaic and betavoltaic cells because their performance degrades, especially with high-energy - (>200keV) beta and alpha particles. Indirect excitation methods, such as the Photon Intermediate Direct Energy Conversion (PIDEC) framework, can protect the transducer from radiation. A nuclear battery using a
Publisher: AIP Publishing
Date: 02-2008
DOI: 10.1063/1.2837517
Abstract: Data collected with automated double and single probes is used to evaluate the convergence of ion flow in a spherical inertial electrostatic confinement device operated in glow discharge mode. A novel method based on the invasive nature of electrostatic probes is used to evaluate the width of the ion density peak. Over much of the star mode discharge regime, it is found that Rc∕Rg∼0.125 to 0.167 where Rc is the ion core radius, and Rg is the radius of the cathode grid, which remains fixed for all discharge conditions considered here. Near the star-to-jet mode transition, the technique shows that Rc∕Rg∼0.250, in agreement with direct measurements of the ion density profile with the double probe. The influences of space charge accumulation and cathode grid deflection are evaluated with floating potential measurements and tangential electric field measurements, respectively. It is concluded that the observed core growth is a result of ion microchannel degradation caused by an increased frequency in inelastic and elastic molecular encounters, while the effects of space charge are negligible.
Publisher: Springer Netherlands
Date: 1995
Publisher: Springer Netherlands
Date: 1997
Publisher: CRC Press
Date: 04-11-2009
Publisher: AIP Publishing
Date: 10-1977
DOI: 10.1063/1.89720
Abstract: Direct nuclear pumping of the 1.45-μ line in neutral carbon has been achieved using the 10B(n,α)7Li reaction. Lasing was observed in mixtures of both He-CO and He-CO2. The laser has the lowest neutron flux threshold to date, ∼4×1014 n/cm2 sec, and a 20-msec lasing time. Lasing occurred at pressures from 20–800 Torr He with partial pressures of CO and CO2 from ∼1–21 mTorr. A delay, increasing to ∼5 msec for lower total pressures, was observed between the peak of the neutron pulse and the peak of the laser signal for mTorr partial pressures of CO2, and for mTorr partial pressures of N2-CO mixtures.
Publisher: IEEE
Date: 06-2007
Publisher: CRC Press
Date: 04-11-2009
Publisher: IEEE
Date: 06-2007
Publisher: CRC Press
Date: 04-11-2009
Publisher: Springer Netherlands
Date: 1997
Publisher: Springer Science and Business Media LLC
Date: 03-01-2012
Publisher: Springer Netherlands
Date: 1995
Publisher: SAGE Publications
Date: 10-2002
Publisher: Springer Netherlands
Date: 1995
Publisher: Springer Netherlands
Date: 2009
Publisher: SAGE Publications
Date: 10-2002
Publisher: Springer Netherlands
Date: 1997
Publisher: Springer Netherlands
Date: 1995
Publisher: Springer Netherlands
Date: 2011
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 04-2007
Publisher: Oxford University Press (OUP)
Date: 31-07-2006
DOI: 10.1017/S1431927606062957
Abstract: Extended abstract of a paper presented at Microscopy and Microanalysis 2006 in Chicago, Illinois, USA, July 30 – August 3, 2006
Publisher: AIP Publishing
Date: 10-1990
DOI: 10.1063/1.1141728
Abstract: A system for imaging complete tokamak edge cross sections using radiation from intrinsic low-Z impurities, such as carbon, with a frequency response of 500 kHz and a spatial resolution of 1–4 cm (depending on the thickness of the radiating region) is being developed. The noise level is determined by the electronics and is ≤2% for the full 500 kHz bandwidth and ≤1% for a 100 kHz subset of that bandwidth. Photon noise is 0.3% for the full 500 kHz bandwidth. This diagnostic can be used for studying fluctuations in Prad(λ), Γz, and Te. Additionally it may be useful for studying marfes and detached plasmas, transport and oscillations during pellet injection, and as a fast disruption precursor monitor.
Publisher: Elsevier BV
Date: 1990
Publisher: Hindawi Limited
Date: 08-1989
DOI: 10.1017/S0263034600007412
Abstract: The products of fusion reactions have unique properties which can be used for direct energy conversion. These products are neutrons and ions. Neutrons can be transported very long distances through solid materials and can interact with certain elements which have a very high absorption cross section. Ions on the other hand have a very short transport length even in a gaseous medium. It is possible to utilize these products in an inertial confinement fusion reactor with two different direct energy conversion devices: a nuclear-pumped laser using neutrons from the fusion reaction a photon generator material combined with a photovoltaic converter using the ionic fusion products. It will be argued that a nuclear-pumped laser can be more efficient than a conventional laser. It will also be shown that an advanced energy conversion concept based on photon production and photovoltaics can produce ICF system efficiencies of 56%.
Publisher: Unpublished
Date: 2014
Publisher: Unpublished
Date: 1992
Publisher: American Chemical Society (ACS)
Date: 09-02-2012
DOI: 10.1021/AM2018628
Abstract: Diamond in nanoparticle form is a promising material that can be used as a robust and chemically stable catalyst support in fuel cells. It has been studied and characterized physically and electrochemically, in its thin film and powder forms, as reported in the literature. In the present work, the electrochemical properties of undoped and boron-doped diamond nanoparticle electrodes, fabricated using the ink-paste method, were investigated. Methanol oxidation experiments were carried out in both half-cell and full fuel cell modes. Platinum and ruthenium nanoparticles were chemically deposited on undoped and boron doped diamond nanoparticles through the use of NaBH(4) as reducing agent and sodium dodecyl benzene sulfonate (SDBS) as a surfactant. Before and after the reduction process, s les were characterized by electron microscopy and spectroscopic techniques. The ink-paste method was also used to prepare the membrane electrode assembly with Pt and Pt-Ru modified undoped and boron-doped diamond nanoparticle catalytic systems, to perform the electrochemical experiments in a direct methanol fuel cell system. The results obtained demonstrate that diamond supported catalyst nanomaterials are promising for methanol fuel cells.
Publisher: Elsevier BV
Date: 06-2012
Publisher: SAGE Publications
Date: 10-2002
Publisher: Unpublished
Date: 2013
Publisher: Springer Science and Business Media LLC
Date: 09-1990
DOI: 10.1007/BF01059248
Publisher: CRC Press
Date: 04-11-2009
Publisher: Springer Netherlands
Date: 1995
Publisher: Unpublished
Date: 1991
Publisher: SAGE Publications
Date: 10-2002
Publisher: Unpublished
Date: 1979
Publisher: Springer US
Date: 1984
Publisher: Informa UK Limited
Date: 07-2014
DOI: 10.13182/NT11-105
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 12-2018
Publisher: AIP Publishing
Date: 1981
DOI: 10.1063/1.329816
Abstract: The recent report of cw nuclear-pumped lasing and of the measurement of gain on the 3s2-2p4 transition of Ne in mixtures of 3He-Ne by Carter, Rowe, and Schneider has some fundamental problems which lead one to conclude that the oscillation observed was not from the 6328-Å line of Ne. Specifically, calculations using a very optimistic model of the He-Ne laser at the reported conditions do not support the conclusions of Carter et al. The maximum possible small signal gain for the idealized system, which is the upper limit on this quantity, is an order of magnitude smaller that that reported. Additionally, due to the unusually high single-pass cavity losses reported (≳50%), the idealized system could not achieve oscillation.
Publisher: Elsevier BV
Date: 09-2017
Publisher: Unpublished
Date: 1992
Publisher: AIP Publishing
Date: 15-05-1995
DOI: 10.1063/1.359320
Abstract: Diffusion of boron, lithium, nitrogen, oxygen, and hydrogen into type IIa natural diamond was studied. The diffusion was performed in two steps. First, diffusion of Li and oxygen was performed in nitrogen atmosphere at 860 °C for one hour. The s le was then placed in a hot filament chemical vapor deposition (CVD) growth reactor and diffusion was performed for two hours in hydrogen atmosphere from a boron solid source placed on the surface of the s le. The condition of diffusion were those used routinely during CVD growth. After diffusion, the concentration of Li was of the order of 2×1016 cm−3 at the depth of 0.5 micrometer, and oxygen, nitrogen, and boron were found to be in the range (1–4)×1020 cm−3 at the same depth. The diffusion of hydrogen under conditions specific to CVD growth has also been studied for the first time and was found to be quite strong.
Publisher: Hindawi Limited
Date: 03-1995
DOI: 10.1017/S0263034600008879
Abstract: An ICF plant is designed to use nuclear-driven flashl -pumped solid-state lasers as fusion drivers. It is proposed to use a separated fission reactor with aerosol fuel to drive alkali metal excimer flashl s as the pumping source for solid-state lasers. The first observation of nuclear-excited sodium excimer emission at 436 nm in a TRIGA reactor with 815 Torr of He-3 and 60 Torr of sodium vapor (at T = 924 K) is reported. The experiment demonstrates the feasibility of a nuclear-driven alkali metal excimer l . The compatibility of alkali metal excimers with different laser crystals is evaluated for driver efficiency. High overall laser efficiency ensures large fractional output power extraction from nuclear fusion by this plant. The suitability of laser crystals for the ICF plant is also presented.
Publisher: Springer Science and Business Media LLC
Date: 1998
DOI: 10.1557/PROC-555-345
Abstract: Diamond-like carbon films (DLC) 10–40 nm thick were deposited on quartz substrates on an interdigitated planar array of 20 μm Ni electrodes already prepared by lithographic techniques. The influence of the adsorbed molecules onte electrical properties of the thin DLC films was investigated. Current and capacitance-voltage characteristics were examined. Charge-based deep level transient spectroscopy (Q-DLTS) was used for study of adsorption and desorption processes. The strong sensitivity of Q-DLTS spectra to the presence of the vapor water and isopropyl alcohol was found. For ex le, the Q-DLTS signal for some deposited DLC film was changed more then in order in presence of the water vapor. Such strong surface phenomena of the thin DLC films may be exploited in novel gas sensor devices.
Publisher: Informa UK Limited
Date: 12-2014
Publisher: Springer Science and Business Media LLC
Date: 11-1994
Abstract: The crystalline quality of a diamond film with two different preferential orientations (100) and (111), obtained in the same run by hot filament chemical deposition, has been studied. The quality of the film determined by Raman spectroscopy measurements was found to be nearly the same for both orientations. The second order Raman spectrum for diamond film was observed by using an infrared excitation.
Publisher: Unpublished
Date: 2014
Publisher: CRC Press
Date: 29-08-2002
Publisher: Springer Science and Business Media LLC
Date: 1994
DOI: 10.1557/PROC-339-325
Abstract: Smooth diamond films have been grown by hot filament chemical vapor deposition under d.c. bias on mirror-polished Si substrates. Films a few micrometers thick were obtained in 30 minutes. Raman spectra showed very broad diamond peaks. X-ray diffraction showed the presence of diamond and also other carbon phase with a line 2.11 Å. With time, the films apparently underwent a phase transformation.
Publisher: Elsevier BV
Date: 11-1995
Publisher: AIP Publishing
Date: 06-1995
DOI: 10.1063/1.359204
Abstract: A method is proposed for the determination of the state of an impurity (donor, acceptor, or deep level) in semiconductor lattice. To demonstrate the method boron was diffused into type Ia natural diamond under a dc electric field. The concentration and diffusion profiles of boron were affected by the applied field. Boron diffuses as a negative ion since it is an acceptor shallow enough to be partially ionized at the temperature of diffusion. The drift velocity of boron ions at the temperature of diffusion was also estimated. The diffusion of lithium and oxygen from a Li2CO3 source in chemical vapor deposited diamond films was performed under bias at 1000 °C in an argon atmosphere. After diffusion, the concentrations of Li, O, and H in the diamond films were found to be around (3–4)×1019 cm−3. No dependence of these concentrations on the applied bias was observed. It was found that the diffusion of Li goes primarily through grain boundaries, which may explain why it does not depend on the applied voltage. Fluorine was present as an impurity in the dopant source. Its concentration in the films was around (1–2)×1017 cm−3 and did depend on the applied bias, indicating that fluorine may have formed a shallow level in the diamond band gap.
Publisher: American Vacuum Society
Date: 11-1994
DOI: 10.1116/1.578945
Abstract: The spatial distributions of electron density and temperature in parallel plate audio frequency (AF) (40 kHz) and radio frequency (RF) (13.56 MHz) magnetron discharges were obtained using double Langmuir probes. At 30 W and 580 mTorr argon, electron density ranged from 5×108/cm3 to 1.5×109/cm3 and electron temperature ranged from 3.4 to 4.6 eV in the AF discharge. For 30 W net power and 580 mTorr argon in the RF discharge, electron density ranged from 2×109/cm3 to 8×109/cm3 and electron temperature ranged from 2.5 to 3.6 eV. Electron temperature in the AF discharge increases as the discharge axis is approached, and is independent of axial position. In the RF discharge electron temperature increases near the electrode surface. Electron density distributions in both discharges show the influence of magnetic fields, with the maximum electron density occurring at the position where the radial component of the magnetic field (parallel to the electrode surface) is at a maximum. In the AF discharge, this influence is no longer apparent at axial distances from the electrode surface beyond 2.5 cm. In the RF discharge, radial variations in electron density characteristic of magnetic confinement are observed throughout the plasma, even at the center plane between electrodes.
Publisher: Elsevier BV
Date: 05-1995
Publisher: CRC Press
Date: 29-08-2002
Publisher: Springer Science and Business Media LLC
Date: 1994
DOI: 10.1557/PROC-339-601
Abstract: The diffusion of oxygen, lithium, chlorine, and fluorine in CVD diamond films was performed under bias at 700 and 1000 °C. SIMS and Auger analyses were used to determine the impurity concentration. After diffusion, the concentrations of Li and O in the diamond films were found to be of the order of (3–4)×10 19 cm -3 . The fluorine concentration was of order of (l-2)×10 17 cm -3 . The conductivity was p-type. The change in the resistivity due to diffusion was nearly nine orders of magnitude for the s le diffused under electric field, and six orders of magnitude for the s les diffused without field. No dependence of the impurity concentration on the applied bias was observed except for fluorine. The fluorine concentration dependence on the electric field indicates that fluorine may have formed a shallow level in the diamond band gap. The fact that large concentrations of impurities can be diffused into diamond films at relatively low temperatures indicates the presence in the films of many lattice defects (including grain boundaries).
Publisher: Springer Science and Business Media LLC
Date: 1996
DOI: 10.1557/PROC-423-649
Abstract: Four CVD diamond films grown on tungsten carbide were used for diffusion. Diffusion was performed in a hydrogen atmosphere. Three methods of diffusion were used: conventional diffusion due to concentration gradient, forced diffusion under a dc electric bias with thermal ionization and forced diffusion with optical and thermal ionization of boron acceptor level in diamond. The temperature dependence of the electrical conductivity of the diffused s les was measured in the temperature range 300–600 K. The increase of approximately six order of magnitude in conductivity of the films doped by forced diffusion was obtained. The s les diffused with boron by conventional diffusion due to concentration gradient showed only one order of magnitude increase in electrical conductivity.
Publisher: Unpublished
Date: 2013
Publisher: Oxford University Press (OUP)
Date: 08-2007
Publisher: Office of Scientific and Technical Information (OSTI)
Date: 24-01-1996
DOI: 10.2172/378901
Publisher: Cambridge University Press (CUP)
Date: 02-2021
Publisher: Elsevier BV
Date: 06-1996
Publisher: Elsevier BV
Date: 10-1995
Publisher: Elsevier BV
Date: 07-1994
Publisher: Unpublished
Date: 2001
Publisher: Springer Science and Business Media LLC
Date: 1993
DOI: 10.1557/PROC-316-355
Abstract: Low energy ion bombardment has been utilized to fabricate rectifying contacts on aluminum nitride grown on single crystal silicon substrates. Bombardment of aluminum nitride with methane was followed by sputter deposition of gold contacts. To our knowledge, this is the first report of rectifying contact formation on aluminum nitride. Scanning electron micrographs show that the initially ordered aluminum nitride surface is significantly altered with low energy methane ion beam exposure. Electrical measurements made on s les which had been partially masked during implantation indicate that rectification is a result of the ion bombardment.
Publisher: Informa UK Limited
Date: 07-1981
Publisher: Hindawi Limited
Date: 12-1991
DOI: 10.1017/S0263034600006583
Abstract: A computer model has been developed and benchmarked for the nuclear-pumped atomic carbon laser. Experiments have been performed with the atomic carbon laser and with the radiolysis of CO 2 as a benchmark for the model. The results of the CO 2 radiolysis are described.
Publisher: AIP Publishing
Date: 10-1990
DOI: 10.1063/1.1141621
Abstract: A hyperbolic energy analyzer (HEA) was used to directly measure electron populations in the mirror mode and cusp mode of 14 keV average temperature electron rings in the Missouri magnetic mirror experiment (M4X). Two distinct populations of electrons were found in the mirror mode: a 17 eV group and a 147 eV group. Two distinct populations of electrons were also found in the cusp mode: a 22 eV group and a 167 eV group.
Publisher: Springer Science and Business Media LLC
Date: 1995
DOI: 10.1557/PROC-416-467
Abstract: A study of boron diffusion into diamond lattice was performed. Diffusion was made in hydrogen atmosphere at 30 torr. Two type IIa diamonds were heated at 1200 and 1400 °C for 20 hours and 5 minutes, respectively. Boron powder was used as a dopant source. The boron concentration profiles of both s les were measured by secondary ion mass spectrometry. Based on Fick's law, the diffusion coefficients were computed.
Publisher: AIP Publishing
Date: 08-1988
DOI: 10.1063/1.1140097
Abstract: The Wien filter is an E×B deflecting analyzer with the electrostatic field perpendicular to the magnetostatic field. The twofold functions of the Wien filter are as an energy analyzer as well as a mass analyzer. It has very high resolution for paraxial charged particle beams with V=E/B, the Wien velocity. Two Wien filters were built and tested for electrons up to 3.5 keV and protons beams of 200 eV. The performance of the two is compared and appears to have features useful for high-temperature plasma diagnostics including simultaneous measurement of energy and mass spectra and high resolution.
Publisher: Springer Science and Business Media LLC
Date: 1995
DOI: 10.1557/PROC-416-223
Abstract: Undoped and 10 B doped diamond films were neutron irradiated at a moderately high fluence level (thermal neutron fluence of 1.3 × 10 20 n/cm 2 and a fast neutron (E 0.1 MeV) fluence of 1.6 × 10 20 n/cm 2 ). The unirradiated, irradiated, irradiated and annealed s les were studied using Fourier Transform Infrared (FTIR) and Raman spectroscopies. A dependence of radiation induced stress on the initial boron concentration was observed. The radiation induced stress was lower for the undoped s les. Correlations between FTIR and Raman data were found. The radiation damage was removed after annealing, as measured by Raman and FTIR spectroscopy.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 07-2017
Publisher: Routledge
Date: 29-08-2002
Publisher: Informa UK Limited
Date: 02-2013
DOI: 10.13182/NT13-A15789
Location: United States of America
No related grants have been discovered for Mark Prelas.