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Sample records for cvd diamond microdosimeter

  1. Investigation on the priming effect of a CVD diamond microdosimeter

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    CVD diamond microdosimeter is an ideal substitute of common Si.GaAs detector for extremely strong radiation experimental environment due to its high band gap energy, fast charge collection, low dielectric constant and hardness. In order to improve its character, a CVD diamond microdosimeter was irradiated by a proton dose of 46 Gy, and a lateral micro-ion beam induced charge (IBIC) technique was utilized to characterize it in low beam current (~fA). It was clearly shown that charge collection efficiency and energy resolution were greatly improved after proton irradiation of that dose. Moreover, the homogeneities of both its counting performance and collection efficiency were enhanced. Proton irradiation of 46 Gy has been proved to be an effective way to prime a CVD diamond.

  2. Investigation on the priming effect of a CVD diamond microdosimeter

    CERN Document Server

    Lu Rong Rong; Jiang Da; Li Xiao Lin; Zhu Jie Qing

    2002-01-01

    CVD diamond microdosimeter is an ideal substitute of common Si, GaAs detector for extremely strong radiation experimental environmental due to its high band gap energy, fast charge collection, low dielectric constant and hardness. In order to improve its character, a CVD diamond microdosimeter was irradiated by a proton dose of 46 Gy, and a lateral micro-ion beam induced charge (IBIC) technique was utilized to characterize it in low beam current (approx fA). It was clearly shown that charge collection efficiency and energy resolution were greatly improved after proton irradiation of that dose. Moreover, the homogeneities of both its counting performance and collection efficiency were enhanced. Proton irradiation of 46 Gy has been proved to be an effective way to prime a CVD diamond

  3. CVD diamond - fundamental phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Yarbrough, W.A. [Pennsylvania State Univ., University Park (United States)

    1993-01-01

    This compilation of figures and diagrams addresses the basic physical processes involved in the chemical vapor deposition of diamond. Different methods of deposition are illustrated. For each method, observations are made of the prominent advantages and disadvantages of the technique. Chemical mechanisms of nucleation are introduced.

  4. The Charge Collection Properties of CVD Diamond

    CERN Document Server

    Behnke, T; Oh, A; Steuerer, J; Wagner, A; Zeuner, W; Behnke, Ties; Hüntemeyer, Petra; Oh, Alexander; Steuerer, Johannes; Wagner, Albrecht; Zeuner, Wolfram

    1998-01-01

    The charge collection properties of CVD diamond have been investigated with ionising radiation. In this study two CVD diamond samples, prepared with electrical contacts have been used as solid state ionisation chambers. The diamonds have been studied with beta particles and 10 keV photons, providing a homogeneous ionisation density and with protons and alpha particles which are absorbed in a thin surface layer. For the latter case a strong decrease of the signal as function of time is observed, which is attributed to polarisation effects inside the diamond. Spatially resolved measurements with protons show a large variation of the charge collection efficiency, whereas for photons and minimum ionising particles the response is much more uniform and in the order of 18%. These results indicate that the applicability of CVD diamond as a position sensitive particle detector depends on the ionisation type and appears to be promising for homogeneous ionisation densities as provided by relativistic charged particles.

  5. CVD diamond pixel detectors for LHC experiments

    Energy Technology Data Exchange (ETDEWEB)

    Wedenig, R.; Adam, W.; Bauer, C.; Berdermann, E.; Bergonzo, P.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K.K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Karl, C.; Kass, R.; Knoepfle, K.T.; Krammer, M.; Logiudice, A.; Lu, R.; Manfredi, P.F.; Manfredotti, C.; Marshall, R.D.; Meier, D.; Mishina, M.; Oh, A.; Pan, L.S.; Palmieri, V.G.; Pernicka, M.; Peitz, A.; Pirollo, S.; Polesello, P.; Pretzl, K.; Procario, M.; Re, V.; Riester, J.L.; Roe, S.; Roff, D.; Rudge, A.; Runolfsson, O.; Russ, J.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Suter, B.; Tapper, R.J.; Tesarek, R.; Trawick, M.; Trischuk, W.; Vittone, E.; Wagner, A.; Walsh, A.M.; Weilhammer, P.; White, C.; Zeuner, W.; Ziock, H.; Zoeller, M.; Blanquart, L.; Breugnion, P.; Charles, E.; Ciocio, A.; Clemens, J.C.; Dao, K.; Einsweiler, K.; Fasching, D.; Fischer, P.; Joshi, A.; Keil, M.; Klasen, V.; Kleinfelder, S.; Laugier, D.; Meuser, S.; Milgrome, O.; Mouthuy, T.; Richardson, J.; Sinervo, P.; Treis, J.; Wermes, N

    1999-08-01

    This paper reviews the development of CVD diamond pixel detectors. The preparation of the diamond pixel sensors for bump-bonding to the pixel readout electronics for the LHC and the results from beam tests carried out at CERN are described.

  6. Superconductivity in CVD diamond films.

    Science.gov (United States)

    Takano, Yoshihiko

    2009-06-24

    A beautiful jewel of diamond is insulator. However, boron doping can induce semiconductive, metallic and superconducting properties in diamond. When the boron concentration is tuned over 3 × 10(20) cm(-3), diamonds enter the metallic region and show superconductivity at low temperatures. The metal-insulator transition and superconductivity are analyzed using ARPES, XAS, NMR, IXS, transport and magnetic measurements and so on. This review elucidates the physical properties and mechanism of diamond superconductor as a special superconductivity that occurs in semiconductors.

  7. Comparative evaluation of CVD diamond technologies

    Energy Technology Data Exchange (ETDEWEB)

    Anthony, T.R. [General Electric Corporate Research & Development Center, Schenectady, NY (United States)

    1993-01-01

    Chemical vapor deposition (CVD) of diamonds occurs from hydrogen-hydrocarbon gas mixtures in the presence of atomic hydrogen at subatmospheric pressures. Most CVD methods are based on different means of generating and transporting atomic hydrogen in a particular system. Evaluation of these different techniques involves their capital costs, material costs, energy costs, labor costs and the type and quality of diamond that they produce. Currently, there is no universal agreement on which is the best technique and technique selection has been largely driven by the professional background of the user as well as the particular application of interest. This article discusses the criteria for evaluating a process for low-pressure deposition of diamond. Next, a brief history of low-pressure diamond synthesis is reviewed. Several specific processes are addressed, including the hot filament process, hot filament electron-assisted chemical vapor deposition, and plasma generation of atomic hydrogen by glow discharge, microwave discharge, low pressure radio frequency discharge, high pressure DC discharge, high pressure microwave discharge jets, high pressure RF discharge, and high and low pressure flames. Other types of diamond deposition methods are also evaluated. 101 refs., 15 figs.

  8. High collection efficiency CVD diamond alpha detectors

    Energy Technology Data Exchange (ETDEWEB)

    Bergonzo, P.; Foulon, F.; Marshall, R.D.; Jany, C.; Brambilla, A. [CEA/Saclay, Gif-sur-Yvette (France); McKeag, R.D.; Jackman, R.B. [University College London (United Kingdom). Electronic and Electrical Engineering Dept.

    1998-06-01

    Advances in Chemical Vapor Deposited (CVD) diamond have enabled the routine use of this material for sensor device fabrication, allowing exploitation of its unique combination of physical properties (low temperature susceptibility (> 500 C), high resistance to radiation damage (> 100 Mrad) and to corrosive media). A consequence of CVD diamond growth on silicon is the formation of polycrystalline films which has a profound influence on the physical and electronic properties with respect to those measured on monocrystalline diamond. The authors report the optimization of physical and geometrical device parameters for radiation detection in the counting mode. Sandwich and co-planar electrode geometries are tested and their performances evaluated with regard to the nature of the field profile and drift distances inherent in such devices. The carrier drift length before trapping was measured under alpha particles and values as high as 40% of the overall film thickness are reported. Further, by optimizing the device geometry, they show that a gain in collection efficiency, defined as the induced charge divided by the deposited charge within the material, can be achieved even though lower bias values are used.

  9. TSC response of irradiated CVD diamond films

    CERN Document Server

    Borchi, E; Bucciolini, M; Guasti, A; Mazzocchi, S; Pirollo, S; Sciortino, S

    1999-01-01

    CVD diamond films have been irradiated with electrons, sup 6 sup 0 Co photons and protons in order to study the dose response to exposure to different particles and energies and to investigate linearity with dose. The Thermally Stimulated Current (TSC) has been studied as a function of the dose delivered to polymethilmetacrilate (PMMA) in the range from 1 to 12 Gy with 20 MeV electrons from a linear accelerator. The TSC spectrum has revealed the presence of two components with peak temperatures of about 470 and 520 K, corresponding to levels lying in the diamond band gap with activation energies of the order of 0.7 - 1 eV. After the subtraction of the exponential background the charge emitted during the heating scan has been evaluated and has been found to depend linearly on the dose. The thermally emitted charge of the CVD diamond films has also been studied using different particles. The samples have been irradiated with the same PMMA dose of about 2 Gy with 6 and 20 MeV electrons from a Linac, sup 6 sup 0 ...

  10. An assessment of radiotherapy dosimeters based on CVD grown diamond

    CERN Document Server

    Ramkumar, S; Conway, J; Whitehead, A J; Sussman, R S; Hill, G; Walker, S

    2001-01-01

    Diamond is potentially a very suitable material for use as a dosimeter for radiotherapy. Its radiation hardness, the near tissue equivalence and chemical inertness are some of the characteristics of diamond, which make it well suited for its application as a dosimeter. Recent advances in the synthesis of diamond by chemical vapour deposition (CVD) technology have resulted in the improvement in the quality of material and increased its suitability for radiotherapy applications. We report in this paper, the response of prototype dosimeters based on two different types (CVD1 and CVD2) of CVD diamond to X-rays. The diamond devices were assessed for sensitivity, dependence of response on dose and dose rate, and compared with a Scanditronix silicon photon diode and a PTW natural diamond dosimeter. The diamond devices of CVD1 type showed an initial increase in response with dose, which saturates after approx 6 Gy. The diamond devices of CVD2 type had a response at low fields (1162.8 V/cm), the CVD2-type devices show...

  11. CVD diamond sensors for charged particle detection

    CERN Document Server

    Krammer, Manfred; Berdermann, E; Bergonzo, P; Bertuccio, G; Bogani, F; Borchi, E; Brambilla, A; Bruzzi, Mara; Colledani, C; Conway, J; D'Angelo, P; Dabrowski, W; Delpierre, P A; Dencuville, A; Dulinski, W; van Eijk, B; Fallou, A; Fizzotti, F; Foulon, F; Friedl, M; Gan, K K; Gheeraert, E; Hallewell, G D; Han, S; Hartjes, F G; Hrubec, Josef; Husson, D; Kagan, H; Kania, D R; Kaplon, J; Kass, R; Koeth, T W; Lo Giudice, A; Lü, R; MacLynne, L; Manfredotti, C; Meier, D; Mishina, M; Moroni, L; Oh, A; Pan, L S; Pernicka, Manfred; Peitz, A; Perera, L P; Pirollo, S; Procario, M; Riester, J L; Roe, S; Rousseau, L; Rudge, A; Russ, J; Sala, S; Sampietro, M; Schnetzer, S; Sciortino, S; Stelzer, H; Stone, R; Suter, B; Tapper, R J; Tesarek, R; Trischuk, W; Tromson, D; Vittone, E; Walsh, A M; Wedenig, R; Weilhammer, Peter; Wetstein, M; White, C; Zeuner, W; Zöller, M

    2001-01-01

    CVD diamond material was used to build position-sensitive detectors for single-charged particles to be employed in high-intensity physics experiments. To obtain position information, metal contacts shaped as strips or pixels are applied to the detector surface for one- or two- dimensional coordinate measurement. Strip detectors 2*4 cm/sup 2/ in size with a strip distance of 50 mu m were tested. Pixel detectors of various pixel sizes were bump bonded to electronics chips and investigated. A key issue for the use of these sensors in high intensity experiments is the radiation hardness. Several irradiation experiments were carried out with pions, protons and neutrons exceeding a fluence of 10/sup 15/ particles/cm/sup 2/. The paper presents an overview of the results obtained with strip and pixel detectors in high-energy test beams and summarises the irradiation studies. (8 refs).

  12. Leakage current measurements of a pixelated polycrystalline CVD diamond detector

    OpenAIRE

    Zain, R.M.; Maneuski, D.; O'Shea, V.; Bates, R.; Blue, A.; Cunnigham, L.; Stehl, C.; Berderman, E.; Rahim, R. A.

    2013-01-01

    Diamond has several desirable features when used as a material for radiation detection. With the invention of synthetic growth techniques, it has become feasible to look at developing diamond radiation detectors with reasonable surface areas. Polycrystalline diamond has been grown using a chemical vapour deposition (CVD) technique by the University of Augsburg and detector structures fabricated at the James Watt Nanofabrication Centre (JWNC) in the University of Glasgow in order to produce pi...

  13. Engineered CVD Diamond Coatings for Machining and Tribological Applications

    Science.gov (United States)

    Dumpala, Ravikumar; Chandran, Maneesh; Ramachandra Rao, M. S.

    2015-07-01

    Diamond is an allotropes of carbon and is unique because of its extreme hardness (~100 GPa), low friction coefficient (fracture toughness can be tuned by controlling the grain size of the coatings from a few microns to a few nanometers. In this review, characteristics and performance of the CVD diamond coatings deposited on cemented tungsten carbide (WC-Co) substrates were discussed with an emphasis on WC-Co grade selection, substrate pretreatment, nanocrystallinity and microcrystallinity of the coating, mechanical and tribological characteristics, coating architecture, and interfacial adhesion integrity. Engineered coating substrate architecture is essential for CVD diamond coatings to perform well under harsh and highly abrasive machining and tribological conditions.

  14. CVD Diamond Sensors In Detectors For High Energy Physics

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00334150; Trischuk, William

    At the end of the next decade an upgrade of the Large Hadron Collider (LHC) to High Luminosity LHC (HL-LHC) is planned which requires the development of new radiation tolerant sensor technology. Diamond is an interesting material for use as a particle detector in high radiation environments. The large band gap ($5.47\\,\\text{eV}$) and the large displacement energy suggest that diamond is a radiation tolerant detector material. In this Thesis the capability of Chemical Vapor Deposition (CVD) diamond as such a sensor technology is investigated. The radiation damage constant for $800\\,\\text{MeV}$ protons is measured using single crystalline CVD (scCVD) and polycrystalline CVD (pCVD) diamonds irradiated to particle fluences up to $12 \\times 10^{15}\\,\\text{p/cm}^2$. In addition the signal response of a pCVD diamond detector after an irradiation to $12 \\times 10^{15}\\,\\text{p/cm}^2$ is investigated to determine if such a detector can be operated efficiently in the expected HL-LHC environment. By using electrodes em...

  15. CVD diamond for electronic devices and sensors

    CERN Document Server

    2009-01-01

    Synthetic diamond is diamond produced by using chemical or physical processes. Like naturally occurring diamond it is composed of a three-dimensional carbon crystal. Due to its extreme physical properties, synthetic diamond is used in many industrial applications, such as drill bits and scratch-proof coatings, and has the potential to be used in many new application areas A brand new title from the respected Wiley Materials for Electronic and Optoelectronic Applications series, this title is the most up-to-date resource for diamond specialists. Beginning with an introduction to the pr

  16. Crystal growth of CVD diamond and some of its peculiarities

    CERN Document Server

    Piekarczyk, W

    1999-01-01

    Experiments demonstrate that CVD diamond can form in gas environments that are carbon undersaturated with respect to diamond. This fact is, among others, the most serious violation of principles of chemical thermodynamics. In this $9 paper it is shown that none of the principles is broken when CVD diamond formation is considered not a physical process consisting in growth of crystals but a chemical process consisting in accretion of macro-molecules of polycyclic $9 saturated hydrocarbons belonging to the family of organic compounds the smallest representatives of which are adamantane, diamantane, triamantane and so forth. Since the polymantane macro-molecules are in every respect identical with $9 diamond single crystals with hydrogen-terminated surfaces, the accretion of polymantane macro- molecules is a process completely equivalent to the growth of diamond crystals. However, the accretion of macro-molecules must be $9 described in a way different from that used to describe the growth of crystals because so...

  17. Field electron emission of diamond films on nanocrystalline diamond coating by CVD method

    Institute of Scientific and Technical Information of China (English)

    CAI Rangqi; CHEN Guanghua; SONG Xuemei; XING Guangjian; FENG Zhenjian; HE Deyan

    2003-01-01

    The preparation process, structure feature and field electron emission characteristic of diamond films on nanocyrstalline diamond coating by the CVD method were studied. The field electron emission measurements on the samples showed that the diamond films have lower turn-on voltage and higher field emission current density. A further detailed theory explanation to the results was given.

  18. Radiation Hardness and Linearity Studies of CVD Diamonds

    CERN Document Server

    Behnke, T; Ghodbane, N; Imhof, A

    2003-01-01

    We report on the behavior of CVD diamonds under intense electromagnetic radiation and on the response of the detector to high density of deposited energy. Diamonds have been found to remain unaffected after doses of 10 MGy of MeV-range photons and the diamond response to energy depositions of up to 250 GeV/cm^3 has been found to be linear to better than 2 %. These observations make diamond an attractive detector material for a calorimeter in the very forward region of the detector proposed for TESLA.

  19. Ultratough CVD single crystal diamond and three dimensional growth thereof

    Science.gov (United States)

    Hemley, Russell J [Washington, DC; Mao, Ho-kwang [Washington, DC; Yan, Chih-shiue [Washington, DC

    2009-09-29

    The invention relates to a single-crystal diamond grown by microwave plasma chemical vapor deposition that has a toughness of at least about 30 MPa m.sup.1/2. The invention also relates to a method of producing a single-crystal diamond with a toughness of at least about 30 MPa m.sup.1/2. The invention further relates to a process for producing a single crystal CVD diamond in three dimensions on a single crystal diamond substrate.

  20. CVD Diamond Sink Application in High Power 3D MCMs

    Institute of Scientific and Technical Information of China (English)

    XIE Kuo-jun; JIANG Chang-shun; LI Cheng-yue

    2005-01-01

    As electronic packages become more compact, run at faster speeds and dissipate more heat, package designers need more effective thermal management materials. CVD diamond, because of its high thermal conductivity, low dielectric loss and its great mechanical strength, is an excellent material for three dimensional (3D) multichip modules (MCMs) in the next generation compact high speed computers and high power microwave components. In this paper, we have synthesized a large area freestanding diamond films and substrates, and polished diamond substrates, which make MCMs diamond film sink becomes a reality.

  1. CVD diamond resistor as heater and temperature sensor

    Energy Technology Data Exchange (ETDEWEB)

    Yang, G.S.; Aslam, M. [Michigan State Univ., East Lansing, MI (United States)

    1995-12-31

    Heat generation and temperature control, essential for most heater applications, require different components in a conventional system. We achieve the heat generation and temperature measurement simultaneously by using a single diamond resistor. Chemical vapor deposited (CVD) p-type diamond resistors with different dimensions were fabricated on polycrystalline diamond or oxidized Si substrates using diamond film technology compatible with integrated circuit (IC) processing. The temperature response of the resistors was characterized in the temperature range of 25 - 500{degrees}C. Power densities in access of 600 watt/in{sup 2} were achieved.

  2. Present limitations of CVD diamond detectors for IMRT applications

    Energy Technology Data Exchange (ETDEWEB)

    De Angelis, C. [Dipartimento di Tecnologie e Salute, Istituto Superiore di Sanita and INFN, Viale regina Elena 299, 00161 Rome (Italy)], E-mail: cinzia.deangelis@iss.it; Casati, M. [Dipartimento di Fisiopatologia dell' Universita and INFN, Florence (Italy); Bruzzi, M. [Dipartimento di Energetica dell' Universita and INFN, Florence (Italy); Onori, S. [Dipartimento di Tecnologie e Salute, Istituto Superiore di Sanita and INFN, Viale regina Elena 299, 00161 Rome (Italy); Bucciolini, M. [Dipartimento di Fisiopatologia dell' Universita and INFN, Florence (Italy)

    2007-12-11

    The aim of the work was to test the suitability of chemical vapor deposited (CVD) diamond detectors for dosimetry in IMRT fields. We used in-house CVD detectors prepared with state-of-the-art polycrystalline diamond films (Element Six Ltd., UK). The parameters considered were time stability, dynamic response, dose-rate dependence and energy dependence. Output factors and TPR were measured in conventional photon fields and dose measurements were performed in IMRT fields using the step-and-shoot technique. Results prove that CVD diamond detectors are suitable for dosimetry in conventional treatments, but they still do not fit the IMRT dosimetry requirements, mainly because of their slow dynamic response. In particular, the slow dynamics affects linearity at low Monitor Units and renders it impossible to follow the sharp transients of IMRT fields. Time stability and dose-rate dependence as well must be improved to reduce their influence on dose assessment.

  3. Development of CVD diamond detectors for clinical dosimetry

    Science.gov (United States)

    Piliero, M. A.; Hugtenburg, R. P.; Ryde, S. J. S.; Oliver, K.

    2014-11-01

    The use of chemical vapour deposition (CVD) methods for the manufacture of diamonds could lead to detectors for high-resolution radiotherapy dosimetry that are cheaper and more reproducible than detectors based on natural diamonds. In this work two prototype designs (Diamond Detectors Ltd, Poole) of CVD diamond detectors were considered. The detectors were encapsulated in a water-proof housing in a form-factor that would be suitable for dosimetry measurements in water, as well as solid material phantoms. Stability of the dosimeter over time, the dose-response, dose-rate response and angular-response were examined. The study demonstrated that the detector behaviour conformed with theory in terms of the dose-rate response and had acceptable properties for use in the clinic.

  4. Physics and applications of CVD diamond

    CERN Document Server

    Koizumi, Satoshi; Nesladek, Milos

    2008-01-01

    Here, leading scientists report on why and how diamond can be optimized for applications in bioelectronic and electronics. They cover such topics as growth techniques, new and conventional doping mechanisms, superconductivity in diamond, and excitonic properties, while application aspects include quantum electronics at room temperature, biosensors as well as diamond nanocantilevers and SAWs.Written in a review style to make the topic accessible for a wider community of scientists working in interdisciplinary fields with backgrounds in physics, chemistry, biology and engineering, this is e

  5. Surface analysis of CVD diamond exposed to fusion plasma

    NARCIS (Netherlands)

    Porro, S.; De Temmerman, G.; MacLaren, D. A.; Lisgo, S.; Rudakov, D. L.; Westerhout, J.; Wiora, M.; John, P.; Villalpando, I.; Wilson, J. I. B.

    2010-01-01

    Microcrystalline undoped and heavily boron-doped polycrystalline diamond layers have been deposited on various substrates by hot filament CVD and exposed to hydrogen plasma in a linear plasma reactor (Pilot-PSI, The Netherlands) that simulates the high flux and high density plasma conditions of toka

  6. CVD Diamonds in the BaBar Radiation Monitoring System

    CERN Document Server

    Bruinsma, M; Edwards, A J; Kagan, H; Kass, R; Kirkby, D; Petersen, B A

    2006-01-01

    To prevent excessive radiation damage to its Silicon Vertex Tracker, the BaBar experiment at SLAC uses a radiation monitoring and protection system that triggers a beam abort whenever radiation levels are anomalously high. The existing system, which employs large area Si PIN diodes as radiation sensors, has become increasingly difficult to operate due to radiation damage. We have studied CVD diamond sensors as a potential alternative for these silicon sensors. Two diamond sensors have been routinely used since their installation in the Vertex Tracker in August 2002. The experience with these sensors and a variety of tests in the laboratory have shown CVD diamonds to be a viable solution for dosimetry in high radiation environments. However, our studies have also revealed surprising side-effects.

  7. X-ray sensitivity measurements on CVD diamond film detectors

    Energy Technology Data Exchange (ETDEWEB)

    Foulon, F.; Pochet, T. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. d`Electronique et d`Instrumentation Nucleaire; Gheeraert, E. [Centre National de la Recherche Scientifique (CNRS), 38 - Grenoble (France)

    1993-12-31

    Microwave chemical vapor deposited (CVD) diamond films have been used to fabricate radiation detectors. The polycrystalline diamond films have a resistivity of 10{sup 12} ohm.cm and carrier mobility and lifetime of about 280 cm{sup 2}/V.s and 530 ps. The detector response to laser pulses (355, 532 and 1064 nm), X-ray flux (15-50 keV) and alpha particles ({sup 241}Am, 5.49 MeV) has been investigated. The response speed of the detector is in the 100 ps range. A sensitivity of about 3 x 10{sup -10} A/V.Gy.s was measured under 50 keV X-ray flux. The detector current response to X-ray flux is almost linear. It is also shown that CVD diamond detectors can be used for alpha particle counting. (authors). 9 figs., 25 refs.

  8. Polycrystalline CVD diamond device level modeling for particle detection applications

    Science.gov (United States)

    Morozzi, A.; Passeri, D.; Kanxheri, K.; Servoli, L.; Lagomarsino, S.; Sciortino, S.

    2016-12-01

    Diamond is a promising material whose excellent physical properties foster its use for radiation detection applications, in particular in those hostile operating environments where the silicon-based detectors behavior is limited due to the high radiation fluence. Within this framework, the application of Technology Computer Aided Design (TCAD) simulation tools is highly envisaged for the study, the optimization and the predictive analysis of sensing devices. Since the novelty of using diamond in electronics, this material is not included in the library of commercial, state-of-the-art TCAD software tools. In this work, we propose the development, the application and the validation of numerical models to simulate the electrical behavior of polycrystalline (pc)CVD diamond conceived for diamond sensors for particle detection. The model focuses on the characterization of a physically-based pcCVD diamond bandgap taking into account deep-level defects acting as recombination centers and/or trap states. While a definite picture of the polycrystalline diamond band-gap is still debated, the effect of the main parameters (e.g. trap densities, capture cross-sections, etc.) can be deeply investigated thanks to the simulated approach. The charge collection efficiency due to β -particle irradiation of diamond materials provided by different vendors and with different electrode configurations has been selected as figure of merit for the model validation. The good agreement between measurements and simulation findings, keeping the traps density as the only one fitting parameter, assesses the suitability of the TCAD modeling approach as a predictive tool for the design and the optimization of diamond-based radiation detectors.

  9. High-rate diamond deposition by microwave plasma CVD

    Science.gov (United States)

    Li, Xianglin

    In this dissertation, the growth of CVD (Chemical Vapor Deposition) diamond thin films is studied both theoretically and experimentally. The goal of this research is to deposit high quality HOD (Highly Oriented Diamond) films with a growth rate greater than 1 mum/hr. For the (100)-oriented HOD films, the growth rate achieved by the traditional process is only 0.3 mum/hr while the theoretical limit is ˜0.45 mum/hr. This research increases the growth rate up to 5.3 mum/hr (with a theoretical limit of ˜7 mum/hr) while preserving the crystal quality. This work builds a connection between the theoretical study of the CVD process and the experimental research. The study is extended from the growth of regular polycrystalline diamond to highly oriented diamond (HOD) films. For the increase of the growth rate of regular polycrystalline diamond thin films, a scaling growth model developed by Goodwin is introduced in details to assist in the understanding of the MPCVD (Microwave Plasma CVD) process. Within the Goodwin's scaling model, there are only four important sub-processes for the growth of diamond: surface modification, adsorption, desorption, and incorporation. The factors determining the diamond growth rate and film quality are discussed following the description of the experimental setup and process parameters. Growth rate and crystal quality models are reviewed to predict and understand the experimental results. It is shown that the growth rate of diamond can be increased with methane input concentration and the amount of atomic hydrogen (by changing the total pressure). It is crucial to provide enough atomic hydrogen to conserve crystal quality of the deposited diamond film. The experimental results demonstrate that for a fixed methane concentration, there is a minimum pressure for growth of good diamond. Similarly, for a fixed total pressure, there is a maximum methane concentration for growth of good diamond, and this maximum methane concentration increases

  10. Origin, state of the art and some prospects of the diamond CVD

    CERN Document Server

    Spitsyn, B V; Alexenko, A E

    2000-01-01

    A short review on the diamond CVD origin, together with its state of the art and some prospects was given. New hybrid methods of the diamond CVD permit to gain 1.2 to 6 times of growth rate in comparison with ordinary diamond CVD's. Recent results on n-type diamond film synthesis through phosphorus doping in the course of the CVD process are briefly discussed. In comparison with high-pressure diamond synthesis, the CVD processes open new facets of the diamond as ultimate crystal for science and technology evolution. It was stressed that, mainly on the basis of new CVDs of diamond, the properties of natural diamond are not only reproduced, but can be surpassed. As examples, mechanical (fracture resistance), physical (thermal conductivity), and chemical (oxidation stability) properties are mentioned. Some present issues in the field are considered.

  11. Electrical conduction in polycrystalline CVD diamond: Temperature dependent impedance measurements

    Energy Technology Data Exchange (ETDEWEB)

    Ye, H.; Williams, O.A.; Jackman, R.B. [Electronic and Electrical Engineering, University College London, Torrington Place, London WC1E 7JE (United Kingdom); Rudkin, R.; Atkinson, A. [Department of Materials, Imperial College London, South Kensington, London SW7 2AZ (United Kingdom)

    2002-10-16

    In this paper, we report the first measurement of impedance on freestanding diamond films from 0.1 Hz to 10 MHz up to 300 C. A wide range of CVD materials have been investigated, but here we concentrate on 'black' diamond grown by MWPECVD. The Cole-Cole (Z' via Z{sup ''}) plots are well fitted to a RC parallel circuit model and the equivalent resistance and capacitance for the diamond films have been estimated using the Zview curve fitting. The results show only one single semicircle response at each temperature measured. It was found that the resistance decreases from 62 M{omega} at room temperature to 4 k{omega} at 300 C, with an activation energy around 0.51 eV. The equivalent capacitance is maintained at the level of 10{sup 2} pF up to 300 C, suggesting that the diamond grain boundaries are dominating the conduction. At 400 C, the impedance at low frequencies shows a linear tail, which can be explained that the ac polarization of diamond/Au interface occurs. (Abstract Copyright [2002], Wiley Periodicals, Inc.)

  12. CVD diamond sensor for UV-photon detection

    CERN Document Server

    Periale, L; Gervino, G; Lamarina, A M; Palmisano, C; Periale, R; Picchi, P

    2012-01-01

    A new generation of UV photosensors, based on single crystal Chemical Vapour Deposition (CVD) diamonds to work optically coupled with large volume two-phase liquid-Ar (LAr) or liquid-Xe (LXe) detectors nowadays under design for the next generation of WIMPs experiments, is under development. Preliminary tests and first calibrations show these devices can have better performance than the existing UV sensitive detectors (higher photosensitivity and better signal-to-noise ratio). I-V characteristics, dark current measurements, linearity response to X-ray irradiation, and alpha-particle energy resolution are reported and discussed. (C) 2011 Elsevier B.V. All rights reserved.

  13. Experimental studies of N~+ implantation into CVD diamond thin films

    Institute of Scientific and Technical Information of China (English)

    辛火平; 林成鲁; 王建新; 邹世昌; 石晓红; 林梓鑫; 周祖尧; 刘祖刚

    1997-01-01

    The effects of N+ implantation under various conditions on CVD diamond films were analyzed with Raman spectroscopy, four-point probe method, X-ray diffraction (XRD), Rutherford backseattering spectroscopy (RBS), ultraviolet photoluminescence spectroscopy (UV-PL), Fourier transformation infrared absorption spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The results show that the N+ implantation doping without any graphitization has been successfully realized when 100 keV N+ ions at a dosage of 2 × 1016 cm-2 were implanted into diamond films at 550℃ . UV-PL spectra indicate that the implanted N+ ions formed an electrically inactive deep-level impurity in diamond films. So the sheet resistance of the sample after N+ implantation changed little. Carbon nitride containing C≡N covalent bond has been successfully synthesized by 100 keV, 1.2×1018 N/cm2 N+ implantation into diamond films. Most of the implanted N+ ions formed C≡N covalent bonds with C atoms. The others were free state nitroge

  14. The evaluation of radiation damage parameter for CVD diamond

    Science.gov (United States)

    Grilj, V.; Skukan, N.; Jakšić, M.; Pomorski, M.; Kada, W.; Kamiya, T.; Ohshima, T.

    2016-04-01

    There are a few different phenomenological approaches that aim to track the dependence of signal height in irradiated solid state detectors on the fluence of damaging particles. However, none of them are capable to provide a unique radiation hardness parameter that would reflect solely the material capability to withstand high radiation environment. To extract such a parameter for chemical vapor deposited (CVD) diamond, two different diamond detectors were irradiated with proton beams in MeV energy range and subjected afterwards to ion beam induced charge (IBIC) analysis. The change in charge collection efficiency (CCE) due to defects produced was investigated in context of a theoretical model that was developed on the basis of the adjoint method for linearization of the continuity equations of electrons and holes. Detailed modeling of measured data resulted with the first known value of the kσ product for diamond, where k represents the number of charge carriers' traps created per one simulated primary lattice vacancy and σ represents the charge carriers' capture cross section. As discussed in the text, this product could be considered as a true radiation damage parameter.

  15. The evaluation of radiation damage parameter for CVD diamond

    Energy Technology Data Exchange (ETDEWEB)

    Grilj, V., E-mail: vgrilj@irb.hr [Division for Experimental Physics, Ruđer Bošković Institute, 10000 Zagreb (Croatia); Skukan, N.; Jakšić, M. [Division for Experimental Physics, Ruđer Bošković Institute, 10000 Zagreb (Croatia); Pomorski, M. [CEA-LIST, Diamond Sensors Laboratory, Gif-sur-Yvette F-91191 (France); Kada, W. [Division of Electronics and Informatics, Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515 (Japan); Kamiya, T.; Ohshima, T. [Japan Atomic Energy Agency (JAEA), Takasaki, Gunma 370-1292 (Japan)

    2016-04-01

    There are a few different phenomenological approaches that aim to track the dependence of signal height in irradiated solid state detectors on the fluence of damaging particles. However, none of them are capable to provide a unique radiation hardness parameter that would reflect solely the material capability to withstand high radiation environment. To extract such a parameter for chemical vapor deposited (CVD) diamond, two different diamond detectors were irradiated with proton beams in MeV energy range and subjected afterwards to ion beam induced charge (IBIC) analysis. The change in charge collection efficiency (CCE) due to defects produced was investigated in context of a theoretical model that was developed on the basis of the adjoint method for linearization of the continuity equations of electrons and holes. Detailed modeling of measured data resulted with the first known value of the kσ product for diamond, where k represents the number of charge carriers’ traps created per one simulated primary lattice vacancy and σ represents the charge carriers’ capture cross section. As discussed in the text, this product could be considered as a true radiation damage parameter.

  16. Excimer Laser Beam Analyzer Based on CVD Diamond

    Science.gov (United States)

    Girolami, Marco; Salvatori, Stefano; Conte, Gennaro

    2010-11-01

    1-D and 2-D detector arrays have been realized on CVD-diamond. The relatively high resistivity of diamond in the dark allowed the fabrication of photoconductive "sandwich" strip (1D) or pixel (2D) detectors: a semitransparent light-receiving back-side contact was used for detector biasing. Cross-talk between pixels was limited by using intermediate guard contacts connected at the same ground potential of the pixels. Each pixel photocurrent was conditioned by a read-out electronics composed by a high sensitive integrator and a Σ-Δ ADC converter. The overall 500 μs conversion time allowed a data acquisition rate up to 2 kSPS. The measured fast photoresponse of the samples in the ns time regime suggests to use the proposed devices for fine tuning feedback of high-power pulsed-laser cavities, whereas solar-blindness guarantees high performance in UV beam diagnostics also under high intensity background illumination. Offering unique properties in terms of thermal conductivity and visible-light transparency, diamond represents one of the most suitable candidate for the detection of high-power UV laser emission. The technology of laser beam profiling is evolving with the increase of excimer lasers applications that span from laser-cutting to VLSI and MEMS technologies. Indeed, to improve emission performances, fine tuning of the laser cavity is required. In such a view, the development of a beam-profiler, able to work in real-time between each laser pulse, is mandatory.

  17. A Fast CVD Diamond Beam Loss Monitor for LHC

    CERN Document Server

    Griesmayer, E; Dobos, D; Effinger, E; Pernegger, H

    2011-01-01

    Chemical Vapour Deposition (CVD) diamond detectors were installed in the collimation area of the CERN LHC to study their feasibility as Fast Beam Loss Monitors in a high-radiation environment. The detectors were configured with a fast, radiation-hard pre-amplifier with a bandwidth of 2 GHz. The readout was via an oscilloscope with a bandwidth of 1 GHz and a sampling rate of 5 GSPS. Despite the 250 m cable run from the detectors to the oscilloscope, single MIPs were resolved with a 2 ns rise time, a pulse width of 10 ns and a time resolution of less than 1 ns. Two modes of operation were applied. For the analysis of unexpected beam aborts, the loss profile was recorded in a 1 ms buffer and, for nominal operation, the histogram of the time structure of the losses was recorded in synchronism with the LHC period of 89.2 μs. Measurements during the LHC start-up (February to December 2010) are presented. The Diamond Monitors gave an unprecedented insight into the time structure of the beam losses resolving the 400...

  18. Dosimetric characterization of CVD diamonds irradiated with 62 MeV proton beams

    Energy Technology Data Exchange (ETDEWEB)

    Cirrone, G.A.P. [Laboratori Nazionali del Sud, INFN, Catania (Italy)]. E-mail: cirrone@lns.infn.it; Cuttone, G. [Laboratori Nazionali del Sud, INFN, Catania (Italy); Lo Nigro, S. [Laboratori Nazionali del Sud, INFN, Catania (Italy); Dipartimento di Fisica ed Astronomia, Universita di Catania (Italy); CSFNSM Centro Siciliano di Fisica Nucleare e Struttura della MAteria, Catania (Italy); Mongelli, V. [Laboratori Nazionali del Sud, INFN, Catania (Italy); Scuola di Specializzazione in Fisica Sanitaria, Universita di Catania (Italy); CSFNSM Centro Siciliano di Fisica Nucleare e Struttura della MAteria, Catania (Italy); Raffaele, L. [Laboratori Nazionali del Sud, INFN, Catania (Italy); Sabini, M.G. [Laboratori Nazionali del Sud, INFN, Catania (Italy); Azienda Ospedaliera Cannizzaro, Catania (Italy); Valastro, L. [Laboratori Nazionali del Sud, INFN, Catania (Italy); Scuola di Specializzazione in Fisica Sanitaria, Universita di Catania (Italy); Bucciolini, M. [Dipartimento di Fisiopatologia Clinica, Universita di Florence (Italy); Onori, S. [Istituto Superiore di Sanita, Rome (Italy)

    2005-10-21

    Diamond is potentially a very suitable material for use as on-line radiation dosimeter. Recent advances in the synthesis of polycrystalline diamond by chemical vapor deposition (CVD) techniques have produced material with electronic properties suitable for dosimetry applications. In this work the possibility to use a segmented commercial CVD detector in the dosimetry of proton beams has been investigated. The response as function of dose, dose rate, the priming and the rise time have been investigated thoroughly. This study shows the suitability of CVD diamond for dosimetry of clinical 62 MeV proton beams.

  19. Friction Properties of Polished Cvd Diamond Films Sliding against Different Metals

    Science.gov (United States)

    Lin, Zichao; Sun, Fanghong; Shen, Bin

    2016-11-01

    Owing to their excellent mechanical and tribological properties, like the well-known extreme hardness, low coefficient of friction and high chemical inertness, chemical vapor deposition (CVD) diamond films have found applications as a hard coating for drawing dies. The surface roughness of the diamond films is one of the most important attributes to the drawing dies. In this paper, the effects of different surface roughnesses on the friction properties of diamond films have been experimentally studied. Diamond films were fabricated using hot filament CVD. The WC-Co (Co 6wt.%) drawing dies were used as substrates. A gas mixture of acetone and hydrogen gas was used as the feedstock gas. The CVD diamond films were polished using mechanical polishing. Polished diamond films with three different surface roughnesses, as well as the unpolished diamond film, were fabricated in order to study the tribological performance between the CVD diamond films and different metals with oil lubrication. The unpolished and polished CVD diamond films are characterized with scanning electron microscope (SEM), atomic force microscope (AFM), surface profilometer, Raman spectrum and X-ray diffraction (XRD). The friction examinations were carried out by using a ball-on-plate type reciprocating friction tester. Low carbide steel, stainless steel, copper and aluminum materials were used as counterpart balls. Based on this study, the results presented the friction coefficients between the polished CVD films and different metals. The friction tests demonstrate that the smooth surface finish of CVD diamond films is beneficial for reducing their friction coefficients. The diamond films exhibit low friction coefficients when slid against the stainless steel balls and low carbide steel ball, lower than that slid against copper ball and aluminum ball, attributed to the higher ductility of copper and aluminum causing larger amount of wear debris adhering to the sliding interface and higher adhesive

  20. Study of CVD diamond layers with amorphous carbon admixture by Raman scattering spectroscopy

    Directory of Open Access Journals (Sweden)

    Dychalska Anna

    2015-12-01

    Full Text Available Raman spectroscopy is a most often used standard technique for characterization of different carbon materials. In this work we present the Raman spectra of polycrystalline diamond layers of different quality, synthesized by Hot Filament Chemical Vapor Deposition method (HF CVD. We show how to use Raman spectroscopy for the analysis of the Raman bands to determine the structure of diamond films as well as the structure of amorphous carbon admixture. Raman spectroscopy has become an important technique for the analysis of CVD diamond films. The first-order diamond Raman peak at ca. 1332 cm−1 is an unambiguous evidence for the presence of diamond phase in the deposited layer. However, the existence of non-diamond carbon components in a CVD diamond layer produces several overlapping peaks in the same wavenumber region as the first order diamond peak. The intensities, wavenumber, full width at half maximum (FWHM of these bands are dependent on quality of diamond layer which is dependent on the deposition conditions. The aim of the present work is to relate the features of diamond Raman spectra to the features of Raman spectra of non-diamond phase admixture and occurrence of other carbon structures in the obtained diamond thin films.

  1. Simulation of a perfect CVD diamond Schottky diode steep forward current–voltage characteristic

    Energy Technology Data Exchange (ETDEWEB)

    Kukushkin, V.A., E-mail: vakuk@appl.sci-nnov.ru [Institute of Applied Physics of the Russian Academy of Science, 46 Ulyanov St., 603950 Nizhny Novgorod (Russian Federation); Nizhny Novgorod State University named after N.I. Lobachevsky, 23 Gagarin pr., 603950 Nizhny Novgorod (Russian Federation)

    2016-10-01

    The kinetic equation approach to the simulation of the perfect CVD diamond Schottky diode current–voltage characteristic is considered. In result it is shown that the latter has a significantly steeper forward branch than that of perfect devices of such a type on usual semiconductors. It means that CVD diamond-based Schottky diodes have an important potential advantage over analogous devices on conventional materials.

  2. Simulation of a perfect CVD diamond Schottky diode steep forward current-voltage characteristic

    Science.gov (United States)

    Kukushkin, V. A.

    2016-10-01

    The kinetic equation approach to the simulation of the perfect CVD diamond Schottky diode current-voltage characteristic is considered. In result it is shown that the latter has a significantly steeper forward branch than that of perfect devices of such a type on usual semiconductors. It means that CVD diamond-based Schottky diodes have an important potential advantage over analogous devices on conventional materials.

  3. Hydrogen termination of CVD diamond films by high-temperature annealing at atmospheric pressure

    NARCIS (Netherlands)

    Seshan, V.; Ullien, D.; Castellanos-Gomez, A.; Sachdeva, S.; Murthy, D.H.K.; Savenije, T.J.; Ahmad, H.A.; Nunney, T.S.; Janssens, S.D.; Haenen, K.; Nesládek, M.; Van der Zant, H.S.J.; Sudhölter, E.J.R.; De Smet, L.C.P.M.

    2013-01-01

    A high-temperature procedure to hydrogenate diamond films using molecular hydrogen at atmospheric pressure was explored. Undoped and doped chemical vapour deposited (CVD) polycrystalline diamond films were treated according to our annealing method using a H2 gas flow down to ∼50 ml/min (STP) at ∼850

  4. Recent Results from Beam Tests of 3D and Pad pCVD Diamond Detectors

    CERN Document Server

    Wallny, Rainer

    2017-01-01

    Results from prototypes of a detector using chemical vapor deposited (CVD) diamond with embedded resistive electrodes in the bulk forming a 3D diamond device are presented. A detector system consisting of 3D devices based on poly-crystalline CVD (pCVD) diamond was connected to a multi-channel readout and successfully tested in a 120 GeV/c proton beam at CERN proving for the first time the feasibility of the 3D detector concept in pCVD for particle tracking applications. We also present beam test results on the dependence of signal size on incident particle rate in charged particle detectors based on poly-crystalline CVD diamond. The detectors were tested in a 260 MeV/c pion beam over a range of particle fluxes from 2 kHz/cm2 to 10 MHz/cm2 . The pulse height of the sensors was measured with pad readout electronics at a peaking time of 7 ns. Our data from the 2015 beam tests at PSI indicate that the pulse height of poly-crystalline CVD diamond sensor irradiated to 5×1014 neq/cm2 is independent of particle flux...

  5. Relationship between texture and residual macro-strain in CVD diamond films based on phenomenological analysis

    Institute of Scientific and Technical Information of China (English)

    Weimin Mao; Hongxi Zhu; Leng Chen; Huiping Feng

    2008-01-01

    The relationship between texture and elastic properties of chemical vapor deposition (CVD) diamond films was analyzed based on the phenomenological theory, which reveals the influence of crystalline orientation and texture on the residual macro-strain and macro-stress. The phenomenological calculations indicated that the difference in Young's modulus could be 15% in single dia- mond crystals and 5% in diamond films with homogeneously distributed strong fiber texture. The experimentally measured residual strains of free-standing CVD diamond films were in good agreement with the correspondingly calculated Young's modulus in con- nection with the multi-fiber textures in the fills, though the difference in Young's modulus induced by texture was only around 1%. It is believed that texture should be one of the important factors influencing the residual stress and strain of CVD diamond films.

  6. Biocompatibility and Surface Studies of Microwave CVD Diamond Films

    Science.gov (United States)

    Davis, Brian; Garguilo, J. M.; Koeck, F. A. M.; Nemanich, R. J.; Price, K. J.

    2002-03-01

    The structure and surface properties of a variety of diamond and diamond like carbon films were studied at the nano-scale, in an attempt to assess the biocompatibility of these surfaces. The process of microwave chemical vapor deposition was used to deposit undoped diamond, nitrogen doped diamond, diamond with a titanium monolayer, and diamond-like carbon samples. The contact angles of de-ionized water droplets on the surface of the samples were measured to analyze the surface energy of each film. The rms roughness values of the diamond films measured by atomic force microscopy were also used in determining surface characteristics. Surface treatments of hydrogen passivation, and oxidization were applied to the surface of each film. Hydrogen passivation of the undoped diamond, and nitrogen doped diamond surfaces increases the contact angle on average 30 degrees. Oxidation of the surface decreases the contact angle on average 20 degrees. The surface treatments did not significantly change the contact angle of the diamond like carbon films. Protein adsorption is the first event to take place at a tissue/material interface of an implant into the body, and fibrinogen is the major surface protein, which initiates coagulation and inflammation in the body. The adsorption of fibrinogen was used as an indicator of the biocompatibility of these diamond materials. Fibrinogen was applied to the diamond, and diamond like carbon films. A correlation between contact angle/surface energy, roughness, and the fibrinogen adsorption of these diamond surfaces is reported. There was no significant change in the contact angles following the application of fibrinogen to the surface of the films. This could indicate the biocompatibility of the diamond films. This work supported by the NSF REU program at NCSU and a Physical Sciences Student Research grant from MSU.

  7. Room temperature CVD diamond X-ray and charged particle microdetectors

    CERN Document Server

    Vittone, E; Lo Giudice, A; Polesello, P; Manfredotti, C

    1999-01-01

    Hot filament chemical vapour deposition technique is particularly suitable for the realisation of diamond tip and wire detectors working in a coaxial geometry with a built-in internal metal electrode. By using tungsten wires of different diameters and by controlling the shape of the tip by an electrochemical etch, it is possible to obtain various kinds of microdetectors, with diameters ranging from 50 to 300 mu m. The response of these diamond tip and wire detectors has been tested at low X-ray energies (50-250 keV) and at relatively high energies (6-15 MeV) both in terms of sensitivity (collected charge with respect to the absorbed dose) and of linearity as a function of X-ray fluence. Sensitivities larger than 2 nC/Gy are achieved, with a good linearity in the dose rate range used in applications. Such microprobes have been proved to be suitable as narrow X-ray beam profilers and as surface or in vivo microdosimeters for on-line monitoring of radiotherapy plans. Such detectors have also been used as nuclear...

  8. Systematic study of pre-irradiation effects in high efficiency CVD diamond nuclear particle detectors

    CERN Document Server

    Marinelli, M; Milani, E; Paoletti, A; Pillon, M; Tucciarone, A; Verona-Rinati, G

    2002-01-01

    Many outstanding properties of diamond can, in principle, lead to the development of radiation detectors with interesting capabilities. In particular, diamond-based nuclear particle detectors are good candidates to replace silicon-based detectors in several fields, e.g. in high-flux applications such as next generation particle-accelerator experiments or beam monitoring. However, the high concentration of defects (grain boundaries, impurities) in synthetic diamond films can strongly limit the detector's performance. A significant increase in the efficiency of CVD diamond detectors is achieved by means of pre-irradiation (pumping) with beta particles. We report here on a systematic study of the effects of pumping in high-quality microwave CVD diamond films. The efficiency (eta) and charge collection distance (CCD) of nuclear particle detectors based on these films depend on the methane content in the growth gas mixture and on the film thickness. Both efficiency and CCD behave in a markedly different way in the...

  9. OSL and TL dosimeter characterization of boron doped CVD diamond films

    Science.gov (United States)

    Gonçalves, J. A. N.; Sandonato, G. M.; Meléndrez, R.; Chernov, V.; Pedroza-Montero, M.; De la Rosa, E.; Rodríguez, R. A.; Salas, P.; Barboza-Flores, M.

    2005-04-01

    Natural diamond is an exceptional prospect for clinical radiation dosimetry due to its tissue-equivalence properties and being chemically inert. The use of diamond in radiation dosimetry has been halted by the high market price; although recently the capability of growing high quality CVD diamond has renewed the interest in using diamond films as radiation dosimeters. In the present work we have characterized the dosimetric properties of diamond films synthesized by the HFCVD method. The thermoluminescence and the optically stimulated luminescence of beta exposed diamond sample containing a B/C 4000 ppm doping presents excellent properties suitable for dosimetric applications with β-ray doses up to 3.0 kGy. The observed OSL and TL performance is reasonable appropriate to justify further investigation of diamond films as dosimeters for ionizing radiation, specially in the radiotherapy field where very well localized and in vivo and real time radiation dose applications are essential.

  10. The conductivity of high-fluence noble gas ion irradiated CVD polycrystalline diamond

    Science.gov (United States)

    Borisov, A. M.; Kazakov, V. A.; Mashkova, E. S.; Ovchinnikov, M. A.; Shemukhin, A. A.; Sigalaev, S. K.

    2017-09-01

    The conductivity of surface layer of polycrystalline CVD (Chemical Vapor Deposition) diamond has been studied experimentally after high-fluence 30 keV Ne+, 20 and 30 keV Ar+ ion irradiation at target temperature range from 30 to 400 °C. The hot ion irradiation of CVD diamond may be described as ion-stimulated heat graphitization in which an exponential resistance decrease with increasing of the irradiation temperature is much faster than at the heat treatment. Under ion irradiation of CVD diamond the graphite-like materials resistivity is achieved at temperatures not exceeding 200 °C. The graphite phase in a heterogeneous structure of diamond irradiated layer is in dynamic equilibrium. In the temperature range from RT to 400 °C, the proportion of graphite phase increases so that at temperatures 200 < Tir < 400 °C it is dominant. The Raman spectra of ion-induced conductive layer created on CVD diamond reflect the processes of nanostructural ordering - disordering of sp2-bonded carbon.

  11. A 3D tomographic EBSD analysis of a CVD diamond thin film

    Directory of Open Access Journals (Sweden)

    Tao Liu, Dierk Raabe and Stefan Zaefferer

    2008-01-01

    Full Text Available We have studied the nucleation and growth processes in a chemical vapor deposition (CVD diamond film using a tomographic electron backscattering diffraction method (3D EBSD. The approach is based on the combination of a focused ion beam (FIB unit for serial sectioning in conjunction with high-resolution EBSD. Individual diamond grains were investigated in 3-dimensions particularly with regard to the role of twinning.

  12. CVD diamond coatings on titanium : Characterisation by XRD techniques

    Energy Technology Data Exchange (ETDEWEB)

    Cappuccio, G. [CNR, Frascati, Rome (Italy). Istituto di Strutturistica Chimica]|[INFN-LNF, Frascati, Rome (Italy). Laboratorio Dafne Luce

    1996-09-01

    Here, the authors report an analysis carried out on diamond coatings on titanium substrates to show the potentially of x-ray diffraction techniques in the structural characterisation both of diamond thin films and of the other phases (TiC and TiH{sub 2}) present in the interfacial layer. It should be noted that the composition and microstructure of the interface layers strongly affect the characteristics of the diamond films, particularly adhesion, which is one of the most important elements determining the final quality of the coating.

  13. Proton Irradiation of CVD Diamond Detectors for High Luminosity Experiments at the LHC

    CERN Document Server

    Meier, D; Bauer, C; Berdermann, E; Bergonzo, P; Bogani, F; Borchi, E; Bruzzi, Mara; Colledani, C; Conway, J; Dabrowski, W; Delpierre, P A; Deneuville, A; Dulinski, W; van Eijk, B; Fallou, A; Foulon, F; Friedl, M; Gan, K K; Gheeraert, E; Grigoriev, E A; Hallewell, G D; Hall-Wilton, R; Han, S; Hartjes, F G; Hrubec, Josef; Husson, D; Jany, C; Kagan, H; Kania, D R; Kaplon, J; Kass, R; Knöpfle, K T; Krammer, Manfred; Manfredi, P F; Marshall, R D; Mishina, M; Le Normand, F; Pan, L S; Palmieri, V G; Pernegger, H; Pernicka, Manfred; Peitz, A; Pirollo, S; Pretzl, Klaus P; Re, V; Riester, J L; Roe, S; Roff, D G; Rudge, A; Schnetzer, S R; Sciortino, S; Speziali, V; Stelzer, H; Stone, R; Tapper, R J; Tesarek, R J; Thomson, G B; Trawick, M L; Trischuk, W; Turchetta, R; Walsh, A M; Wedenig, R; Weilhammer, Peter; Ziock, H J; Zöller, M

    1999-01-01

    CVD diamond shows promising properties for use as a position sensitive detector for experiments in the highest radiation areas at the Large Hadron Collider. In order to study the radiation hardn ess of diamond we exposed CVD diamond detector samples to 24~GeV/$c$ and 500~MeV protons up to a fluence of $5\\times 10^{15}~p/{\\rm cm^2}$. We measured the charge collection distance, the ave rage distance electron hole pairs move apart in an external electric field, and leakage currents before, during, and after irradiation. The charge collection distance remains unchanged up to $1\\ times 10^{15}~p/{\\rm cm^2}$ and decreases by $\\approx$40~\\% at $5\\times 10^{15}~p/{\\rm cm^2}$. Leakage currents of diamond samples were below 1~pA before and after irradiation. The particle indu ced currents during irradiation correlate well with the proton flux. In contrast to diamond, a silicon diode, which was irradiated for comparison, shows the known large increase in leakage curren t. We conclude that CVD diamond detectors are radia...

  14. The first bump-bonded pixel detectors on CVD diamond

    Energy Technology Data Exchange (ETDEWEB)

    Adam, W.; Bauer, C.; Berdermann, E.; Bergonzo, P.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fizzotti, F.; Foulon, F.; Friedl, M.; Gan, K.K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Karl, C.; Kass, R.; Krammer, M.; Logiudice, A.; Lu, R.; Manfredi, P.F.; Manfredotti, C.; Marshall, R.D.; Meier, D.; Mishina, M.; Oh, A.; Palmieri, V.G.; Pan, L.S.; Peitz, A.; Pernicka, M.; Pirollo, S.; Polesello, P.; Pretzl, K.; Re, V.; Riester, J.L.; Roe, S.; Roff, D.; Rudge, A.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Steuerer, J.; Stone, R.; Tapper, R.J.; Tesarek, R.; Trawick, M.; Trischuk, W. E-mail: william@physics.utoronto.ca; Turchetta, R.; Vittone, E.; Wagner, A.; Walsh, A.M.; Wedenig, R.; Weilhammer, P.; Zeuner, W.; Ziock, H.; Zoeller, M.; Charles, E.; Ciocio, A.; Dao, K.; Einsweiler, K.; Fasching, D.; Gilchriese, M.; Joshi, A.; Kleinfelder, S.; Milgrome, O.; Palaio, N.; Richardson, J.; Sinervo, P.; Zizka, G

    1999-11-01

    Diamond is a nearly ideal material for detecting ionising radiation. Its outstanding radiation hardness, fast charge collection and low leakage current allow it to be used in high radiation environments. These characteristics make diamond sensors particularly appealing for use in the next generation of pixel detectors. Over the last year, the RD42 collaboration has worked with several groups that have developed pixel readout electronics in order to optimise diamond sensors for bump-bonding. This effort resulted in an operational diamond pixel sensor that was tested in a pion beam. We demonstrate that greater than 98% of the channels were successfully bump-bonded and functioning. The device shows good overall hit efficiency as well as clear spatial hit correlation to tracks measured in a silicon reference telescope. A position resolution of 14.8 {mu}m was observed, consistent with expectations given the detector pitch.

  15. CVD grown diamond: A new material for high power CO{sub 2}-lasers

    Energy Technology Data Exchange (ETDEWEB)

    Massart, M.; Union, P.; Muys, P. [Radius Engineering N.V., Gent (Belgium)] [and others

    1996-12-31

    In CO{sub 2} laser engineering, combining high output power with low distortion of the laser beam is an ongoing challenge, leading to a search for optics with low absorption and high thermal conductivity. As CVD diamond has recently become available in larger sizes and with better surface quality, this material can now be assessed for use in high power CO{sub 2} laser optics. This paper presents the systematic study of diamond as a substrate material for optics at 10.6 microns. CO{sub 2}-laser calorimetry has been used for the measurement of absorption of laser power in uncoated and antireflection coated diamond optics. The bulk absorption coefficient of natural and CVD diamond is more than a magnitude higher than that of ZnSe, however, a laser window needs to be antireflection coated, and this (together with the ability to use thinner windows of diamond because of its greater strength) reduces the increase in overall absorption for the window to about a factor of three (or {approximately} 0.7%). In high power applications this is more than compensated for by the substantially higher thermal conductivity of diamond. Laser induced damage threshold (LIDT) measurements have been made on antireflection coated diamond optics. These measurements have been performed using a TEA CO{sub 2}-laser with a peak pulse width of 150 ns at 10.6 microns, and the results are reported here.

  16. CVD Diamond Detector Stability Issues for Operation at the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, G J; Koch, J A; Moran, M J; Lerche, R A; Izumi, N; Phillips, T W; Glebov, V Y; Sangster, T C; Stoeckl, C

    2003-08-22

    Synthetic diamond crystals produced by the Chemical Vapor Deposition (CVD) technique can serve as fast, radiation hard, neutron sensors for the National Ignition Facility (NIF). Here we explore the stability issues, such as charge trapping and high-flux saturation, that will be relevant to operation at the NIF.

  17. Response of CVD Diamond Detectors to 14 MeV Neutrons

    CERN Document Server

    Weiss, C; Gagnon-Moisan, F; Kasper, A; Lucke, A; Schuhmacher, H; Weierganz, M; Zimba, A

    2012-01-01

    A series of measurements was taken at the Physikalisch-Technische Bundesanstalt (PTB) Braunschweig [1] using the 14 MeV neutron beam at the Van der Graaf accelerator with chemical vapor deposition (CVD) diamond detectors, in preparation of an upcoming (n, ) cross-section measurement [2] at the CERN-n TOF experiment [3, 4]. A single-crystal (sCVD) as well as a poly-crystalline (pCVD) diamond detector were used for the measurements. The response of both materials to the mono-energetic neutron beam was studied, also with the prospect for future applications in plasma diagnostics for fusion research. The results of the measurements are presented in this report.

  18. Pulse-shape analysis for gamma background rejection in thermal neutron radiation using CVD diamond detectors

    Energy Technology Data Exchange (ETDEWEB)

    Kavrigin, P., E-mail: pavel.kavrigin@cividec.at [Vienna University of Technology (Austria); Finocchiaro, P., E-mail: finocchiaro@lns.infn.it [INFN Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); Griesmayer, E., E-mail: erich.griesmayer@cividec.at [Vienna University of Technology (Austria); Jericha, E., E-mail: jericha@ati.ac.at [Vienna University of Technology (Austria); Pappalardo, A., E-mail: apappalardo@lns.infn.it [INFN Laboratori Nazionali del Sud, via S.Sofia 62, 95123 Catania (Italy); Weiss, C., E-mail: Christina.Weiss@cern.ch [Vienna University of Technology (Austria); European Organisation for Nuclear Research (CERN), Geneva (Switzerland)

    2015-09-21

    A novel technique for the rejection of gamma background from charged-particle spectra was demonstrated using a CVD diamond detector with a {sup 6}Li neutron converter installed at a thermal neutron beamline of the TRIGA research reactor at the Atominstitut (Vienna University of Technology). Spectra of the alpha particles and tritons of {sup 6}Li(n,T){sup 4}He thermal neutron capture reaction were separated from the gamma background by a new algorithm based on pulse-shape analysis. The thermal neutron capture in {sup 6}Li is already used for neutron flux monitoring, but the ability to remove gamma background allows using a CVD diamond detector for thermal neutron counting. The pulse-shape analysis can equally be applied to all cases where the charged products of an interaction are absorbed in the diamond and to other background particles that fully traverse the detector.

  19. A novel Mo-W interlayer approach for CVD diamond deposition on steel

    Directory of Open Access Journals (Sweden)

    Vojtěch Kundrát

    2015-04-01

    Full Text Available Steel is the most widely used material in engineering for its cost/performance ratio and coatings are routinely applied on its surface to further improve its properties. Diamond coated steel parts are an option for many demanding industrial applications through prolonging the lifetime of steel parts, enhancement of tool performance as well as the reduction of wear rates. Direct deposition of diamond on steel using conventional chemical vapour deposition (CVD processes is known to give poor results due to the preferential formation of amorphous carbon on iron, nickel and other elements as well as stresses induced from the significant difference in the thermal expansion coefficients of those materials. This article reports a novel approach of deposition of nanocrystalline diamond coatings on high-speed steel (M42 substrates using a multi-structured molybdenum (Mo – tungsten (W interlayer to form steel/Mo/Mo-W/W/diamond sandwich structures which overcome the adhesion problem related to direct magnetron sputtering deposition of pure tungsten. Surface, interface and tribology properties were evaluated to understand the role of such an interlayer structure. The multi-structured Mo-W interlayer has been proven to improve the adhesion between diamond films and steel substrates by acting as an effective diffusion barrier during the CVD diamond deposition.

  20. A novel Mo-W interlayer approach for CVD diamond deposition on steel

    Energy Technology Data Exchange (ETDEWEB)

    Kundrát, Vojtěch; Sullivan, John; Ye, Haitao, E-mail: h.ye@aston.ac.uk [School of Engineering and Applied Science, Aston University, Birmingham, B4 7ET (United Kingdom); Zhang, Xiaoling; Cooke, Kevin; Sun, Hailin [Miba Coating Group: Teer Coatings Ltd, West-Stone-House, West-Stone, Berry-Hill-Industrial-Estate, WR9 9AS, Droitwich (United Kingdom)

    2015-04-15

    Steel is the most widely used material in engineering for its cost/performance ratio and coatings are routinely applied on its surface to further improve its properties. Diamond coated steel parts are an option for many demanding industrial applications through prolonging the lifetime of steel parts, enhancement of tool performance as well as the reduction of wear rates. Direct deposition of diamond on steel using conventional chemical vapour deposition (CVD) processes is known to give poor results due to the preferential formation of amorphous carbon on iron, nickel and other elements as well as stresses induced from the significant difference in the thermal expansion coefficients of those materials. This article reports a novel approach of deposition of nanocrystalline diamond coatings on high-speed steel (M42) substrates using a multi-structured molybdenum (Mo) – tungsten (W) interlayer to form steel/Mo/Mo-W/W/diamond sandwich structures which overcome the adhesion problem related to direct magnetron sputtering deposition of pure tungsten. Surface, interface and tribology properties were evaluated to understand the role of such an interlayer structure. The multi-structured Mo-W interlayer has been proven to improve the adhesion between diamond films and steel substrates by acting as an effective diffusion barrier during the CVD diamond deposition.

  1. Single crystal CVD diamond membranes for betavoltaic cells

    Science.gov (United States)

    Delfaure, C.; Pomorski, M.; de Sanoit, J.; Bergonzo, P.; Saada, S.

    2016-06-01

    A single crystal diamond large area thin membrane was assembled as a p-doped/Intrinsic/Metal (PIM) structure and used in a betavoltaic configuration. When tested with a 20 keV electron beam from a high resolution scanning electron microscope, we measured an open circuit voltage (Voc) of 1.85 V, a charge collection efficiency (CCE) of 98%, a fill-factor of 80%, and a total conversion efficiency of 9.4%. These parameters are inherently linked to the diamond membrane PIM structure that allows full device depletion even at 0 V and are among the highest reported up to now for any other material tested for betavoltaic devices. It enables to drive a high short-circuit current Isc up to 7.12 μA, to reach a maximum power Pmax of 10.48 μW, a remarkable value demonstrating the high-benefit of diamond for the realization of long-life radioisotope based micro-batteries.

  2. Electrical transport measurements and emission properties of freestanding single crystalline CVD diamond samples

    Energy Technology Data Exchange (ETDEWEB)

    Deferme, W.; Bogdan, A.; Bogdan, G. [Hasselt University, Institute for Materials Research (IMO), Diepenbeek (Belgium); Haenen, K.; Ceuninck, W. de [Hasselt University, Institute for Materials Research (IMO), Diepenbeek (Belgium); IMEC vzw, Division IMOMEC, Diepenbeek (Belgium); Nesladek, M. [Hasselt University, Institute for Materials Research (IMO), Diepenbeek (Belgium); IMEC vzw, Division IMOMEC, Diepenbeek (Belgium); CEA/Saclay, LIST (CEA-Recherche Technologique)/DETECS/SSTM/LTD, Gif-sur-Yvette (France)

    2007-09-15

    In this work time-of-flight (TOF) measurements are performed on freestanding single crystalline (100) CVD diamond layers with different surface terminations. The transit properties and electron and hole mobility are measured for completely oxidised and completely hydrogenated diamonds. The results clearly show that the different terminations of the diamond surface have an influence on the electrical transport properties. Furthermore, evidence is given that oxygen-induced surface states influence the TOF spectra. Light emission at 235 nm and around 430 nm is observed when applying a pulsed electric field on the diamond. The small peak at 235 nm is attributed to free exciton recombination while the broad band at 430 nm is contributed to A-band luminescence. Emission spectra at voltages as high as 1.4 V/{mu}m are given and compared. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. Study of the triton-burnup process in different JET scenarios using neutron monitor based on CVD diamond

    Science.gov (United States)

    Nemtsev, G.; Amosov, V.; Meshchaninov, S.; Popovichev, S.; Rodionov, R.

    2016-11-01

    We present the results of analysis of triton burn-up process using the data from diamond detector. Neutron monitor based on CVD diamond was installed in JET torus hall close to the plasma center. We measure the part of 14 MeV neutrons in scenarios where plasma current varies in a range of 1-3 MA. In this experiment diamond neutron monitor was also able to detect strong gamma bursts produced by runaway electrons arising during the disruptions. We can conclude that CVD diamond detector will contribute to the study of fast particles confinement and help predict the disruption events in future tokamaks.

  4. Direct optical interfacing of CVD diamond for deported NV-based sensing experiments

    CERN Document Server

    Mayer, Ludovic

    2016-01-01

    Nitrogen-vacancy (NV) defect in diamond is a very promising tool for numerous sensing applications like magnetometry or thermometry. In this paper, we demonstrate a compact and convenient device for magnetic field imaging where a commercial single mode photonic crystal fibre is directly coupled to a commercial CVD ppm diamond. We managed to excite and detect efficiently the luminescence from an ensemble of NV centres and also to perform Electron Spin Resonance (ESR) experiments where the NV hyperfine structure is perfectly resolved under continuous excitation and measurement.

  5. Ion beam induced luminescence characterisation of CVD diamond films

    Energy Technology Data Exchange (ETDEWEB)

    Bettiol, A.A.; Gonon, P.; Jamieson, D.N. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1996-12-31

    The characterisation of the band structure properties of materials and devices by ion microprobe techniques has been made possible at the Melbourne MeV ion microprobe facility with the development of Ion Beam Induced Luminescence (IBIL). A number of diamond films grown by Microwave Plasma Chemical Vapour Deposition (MPCVD) on silicon substrates are analysed. A preliminary study of the luminescence properties of these samples has revealed information not previously obtainable via traditional microprobe techniques. The optical effects of incorporating dopants during the deposition process is determined using IBIL. The presence of trace element impurities introduced during growth is examined by Particle Induced X-ray Emission (PIXE), and a measurement of the film thickness is made using Rutherford Backscattering Spectrometry (RBS). 7 refs., 2 figs.

  6. Gas electron multiplier based on laser-perforated CVD diamond film: First tests

    CERN Document Server

    Franchino, S; Bolshakov, A; Ashkinazi, E; Kalkan, Y; Popovich, A; Komlenok, M; Sosnovtsev, V; Ralchenko, V

    2016-01-01

    Gas electron multiplier (GEM) is widely used in modern gas detectors of ionizing radiation in experiments on high-energy physics at accelerators and in other fields of science. Typically the GEM devices are based on a dielectric foil with holes and electrodes on both sides. GEMs made by radiation-hard dielectrics or wide band-gap semiconductors are desirable for some applications. The results of the first tests of the gas electron multiplier made of radiation-hard materials, such as polycrystalline CVD diamond with a thickness of 100 microns is described. Here we report on fabrication of GEM based on free-standing polycrystalline CVD diamond film and its first test.

  7. CVD diamond wafers as large-area thermoluminescence detectors for measuring the spatial distribution of dose

    Science.gov (United States)

    Marczewska, B.; Bilski, P.; Olko, P.; Olko, P.; Nesládek, M.; Bergonzo, P.; Rbisz, M.; Waligórski, M. P. R.

    2003-09-01

    The applicability of large-area CVD diamond wafers (diameter about 5 cm, thickness about 0.1 mm), read out as thermoluminescence (TL) detectors, for assessing two-dimensional (2-D) dose distribution over their area, was investigated. To obtain 2-D TL images, a special TL reader equipped with large-area planchet and a CCD camera instead of the usual PM tube was developed. Several 2-D TL images: of an alpha source (Am-241), a Ra-226 needle source and a Ru-106 ophthalmic applicator, were measured and high-resolution digital images obtained. Our preliminary results demonstrate the potential capability of large-area CVD diamond wafers, read out as TL detectors, in 2-D dosimetry for medical applications. (

  8. Pulse-height defect in single-crystal CVD diamond detectors

    Energy Technology Data Exchange (ETDEWEB)

    Beliuskina, O.; Imai, N. [The University of Tokyo, Center for Nuclear Study, Wako, Saitama (Japan); Strekalovsky, A.O.; Aleksandrov, A.A.; Aleksandrova, I.A.; Ilich, S.; Kamanin, D.V.; Knyazheva, G.N.; Kuznetsova, E.A.; Mishinsky, G.V.; Pyatkov, Yu.V.; Strekalovsky, O.V.; Zhuchko, V.E. [JINR, Flerov Laboratory of Nuclear Reactions, Dubna, Moscow Region (Russian Federation); Devaraja, H.M. [Manipal University, Manipal Centre for Natural Sciences, Manipal, Karnataka (India); Heinz, C. [II. Physikalisches Institut, Justus-Liebig-Universitaet Giessen, Giessen (Germany); Heinz, S. [II. Physikalisches Institut, Justus-Liebig-Universitaet Giessen, Giessen (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Hofmann, S.; Kis, M.; Kozhuharov, C.; Maurer, J.; Traeger, M. [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Pomorski, M. [CEA, LIST, Diamond Sensor Laboratory, CEA/Saclay, Gif-sur-Yvette (France)

    2017-02-15

    The pulse-height versus deposited energy response of a single-crystal chemical vapor deposition (scCVD) diamond detector was measured for ions of Ti, Cu, Nb, Ag, Xe, Au, and of fission fragments of {sup 252} Cf at different energies. For the fission fragments, data were also measured at different electric field strengths of the detector. Heavy ions have a significant pulse-height defect in CVD diamond material, which increases with increasing energy of the ions. It also depends on the electrical field strength applied at the detector. The measured pulse-height defects were explained in the framework of recombination models. Calibration methods known from silicon detectors were modified and applied. A comparison with data for the pulse-height defect in silicon detectors was performed. (orig.)

  9. Thermoluminescent properties of CVD diamond: applications to ionising radiation dosimetry; Proprietes thermoluminescentes du diamant CVD: applications a la dosimetrie des rayonnements ionisants

    Energy Technology Data Exchange (ETDEWEB)

    Petitfils, A

    2007-09-15

    Remarkable properties of synthetic diamond (human soft tissue equivalence, chemical stability, non-toxicity) make this material suitable for medical application as thermoluminescent dosimeter (TLD). This work highlights the interest of this material as radiotherapy TLD. In the first stage of this work, we looked after thermoluminescent (TL) and dosimetric properties of polycrystalline diamond made by Chemically Vapor Deposited (CVD) synthesis. Dosimetric characteristics are satisfactory as TLD for medical application. Luminescence thermal quenching on diamond has been investigated. This phenomenon leads to a decrease of dosimetric TL peak sensitivity when the heating rate increases. The second part of this work analyses the use of synthetic diamond as TLD in radiotherapy. Dose profiles, depth dose distributions and the cartography of an electron beam obtained with our samples are in very good agreement with results from an ionisation chamber. It is clearly shown that CVD) diamond is of interest to check beams of treatment accelerators. The use of these samples in a control of treatment with Intensity Modulated Radiation Therapy underlines good response of synthetic diamond in high dose gradient areas. These results indicate that CVD diamond is a promising material for radiotherapy dosimetry. (author)

  10. A CVD Diamond Detector for (n,a) Cross-Section Measurements

    CERN Document Server

    Weiss, Christina; Griesmayer, Erich; Guerrero, Carlos

    A novel detector based on the chemical vapor deposition (CVD) diamond technology has been developed in the framework of this PhD, for the experimental determination of (n,a) cross-sections at the neutron time-of-flight facility n_TOF at CERN. The 59Ni(n,a)56Fe cross-section, which is relevant for astrophysical questions as well as for risk-assessment studies in nuclear technology, has been measured in order to validate the applicability of the detector for such experiments. The thesis is divided in four parts. In the introductory part the motivation for measuring (n,a) cross-sections, the experimental challenges for such measurements and the reasons for choosing the CVD diamond technology for the detector are given. This is followed by the presentation of the n_TOF facility, an introduction to neutron-induced nuclear reactions and a brief summary of the interaction of particles with matter. The CVD diamond technology and the relevant matters related to electronics are given as well in this first part of the t...

  11. Deposition of ZnO Films on Freestanding CVD Thick Diamond Films

    Institute of Scientific and Technical Information of China (English)

    SUN Jian; BAI Yi-Zhen; YANG Tian-Peng; XU Yi-Bin; WANG Xin-Sheng; DU Guo-Tong; WU Han-Hua

    2006-01-01

    @@ For ZnO/diamond structured surface acoustic wave (SAW) filters, performance is sensitively dependent on the quality of the ZnO films. In this paper, we prepare highly-oriented and fine grained polycrystalline ZnO thin films with excellent surface smoothness on the smooth nucleation surfaces of freestanding CVD diamond films by metal organic chemical vapour deposition (MOCVD). The properties of the ZnO films are characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence (PL) spectrum. The influences of the deposition conditions on the quality of ZnO films are discussed briefly. ZnO/freestanding thick-diamond-film layered SAW devices with high response frequencies are expected to be developed.

  12. Low temperature growth of diamond films on optical fibers using Linear Antenna CVD system

    Science.gov (United States)

    Ficek, M.; Drijkoningen, S.; Karczewski, J.; Bogdanowicz, R.; Haenen, K.

    2016-01-01

    It is not trivial to achieve a good quality diamond-coated fibre interface due to a large difference in the properties and composition of the diamond films (or use coating even) and the optical fibre material, i.e. fused silica. One of the biggest problems is the high temperature during the deposition which influences the optical fibre or optical fibre sensor structure (e.g. long-period gratings (LPG)). The greatest advantage of a linear antenna microwave plasma enhanced chemical vapor deposition system (LA MW CVD) is the fact that it allows to grow the diamond layers at low temperature (below 300°C) [1]. High quality nanocrystalline diamond (NCD) thin films with thicknesses ranging from 70 nm to 150 nm, were deposited on silicon, glass and optical fibre substrates [2]. Substrates pretreatment by dip-coating and spin coating process with a dispersion consisting of detonation nanodiamond (DND) in dimethyl sulfoxide (DMSO) with polyvinyl alcohol (PVA) has been applied. During the deposition process the continuous mode of operation of the LA MW CVD system was used, which produces a continuous wave at a maximum power of 1.9 kW (in each antenna). Diamond films on optical fibres were obtained at temperatures below 350°C, providing a clear improvement of results compared to our earlier work [3]. The samples were characterized by scanning electron microscopy (SEM) imaging to investigate the morphology of the nanocrystalline diamond films. The film growth rate, film thickness, and optical properties in the VIS-NIR range, i.e. refractive index and extinction coefficient will be discussed based on measurements on reference quartz plates by using spectroscopic ellipsometry (SE).

  13. Effect of CVD-diamond coatings on the tribological performance of cemented tungsten carbide substrates

    Directory of Open Access Journals (Sweden)

    Kaleem Ahmad Najar

    2016-06-01

    Full Text Available A comparison has been documented between nanocrystalline diamond (NCD and microcrystalline diamond (MCD coatings deposited on cemented tungsten carbide (WC-Co substrates with architectures of WC-Co/NCD & WC-Co/MCD, using hot filament chemical vapor deposition (HFCVD technique. In the present work, the frictional characteristics were studied using ball-on-disc type linear reciprocating micro-tribometer, under the application of 1–10N normal loads, when sliding against smooth alumina (Al2O3 ceramic ball for the total duration of 15min, under dry sliding conditions. Nanoindentation tests were also conducted using Berkovich nanoindenter for the purpose of measurement of hardness and elastic modulus values. The average coefficients of friction of MCD and NCD coatings decrease from 0.37 – 0.32 and 0.3 – 0.27 respectively, when the load is increased from 1–10N. However, for conventional WC-Co substrate the average coefficient of friction increases from 0.60–0.75, under the same input operating conditions. The wear tracks formed on the surfaces of CVD-diamond coatings and WC-Co substrate, after friction measurement were characterised using Raman spectroscopy and scanning electron microscopy (SEM techniques. However, the compositional analysis for the formation of tribo-layer observed on the wear tracks of CVD-diamond coatings was confirmed using energy dispersive spectroscopy (EDS technique. Therefore, maintaining an appropriate level of normal load and using appropriate type of diamond coating, friction may be kept to some lower value to improve mechanical processes.

  14. Adhesive strength of CVD diamond thin films quantitatively measured by means of the bulge and blister test

    Institute of Scientific and Technical Information of China (English)

    Daohui Xiang; Ming Chen; Yuping Ma; Fanghong Sun

    2008-01-01

    Large advancement has been made in understanding the nucleation and growth of chemical vapor deposition (CVD) diamond, but the adhesion of CVD diamond to substrates is poor and there is no good method for quantitative evaluation of the adhesive strength. The blister test is a potentially powerful tool for characterizing the mechanical properties of diamond films. In this test, pressure was applied on a thin membrane and the out-of-plane deflection of the membrane center was measured. The Young's modulus, residual stress, and adhesive strength were simultaneously determined using the load-deflection behavior of a membrane. The free-standing window sample of diamond thin films was fabricated by means of photolithography and anisotropic wet etching. The research indicates that the adhesive strength of diamond thin films is 4.28±0.37J/m2. This method uses a simple apparatus, and the fabrication of samples is very easy.

  15. High-Resolution Energy and Intensity Measurements with CVD Diamond at REX-ISOLDE

    CERN Document Server

    Griesmayer, E; Dobos, D; Wenander, F; Bergoz, J; Bayle, H; Frais-Kölbl, H; Leinweber, J; Aumeyr, T; CERN. Geneva. BE Department

    2009-01-01

    A novel beam instrumentation device for the HIE-REX (High In-tensity and Energy REX) upgrade has been developed and tested at the On-Line Isotope Mass Separator ISOLDE, located at the European Laboratory for Particle Physics (CERN). This device is based on CVD diamond detector technology and is used for measuring the beam intensity, particle counting and measuring the energy spectrum of the beam. An energy resolution of 0.6% was measured at a carbon ion energy of 22.8 MeV. This corresponds to an energy spread of ± 140 keV.

  16. A study of the charge collection properties of polycrystalline CVD diamond with synchrotron radiation

    CERN Document Server

    Oh, A; Watts, S; Ahmed, M; Da Via, C

    2011-01-01

    Polycrystalline CVD diamond samples have been prepared with different electrode configurations, allowing to produce an electric field parallel and perpendicular to the direction of the grain boundaries. A photon beam with an energy of 15 key was used to study the response with a spatial resolution of about 7 mu m. Results on the influence of the field direction on the signal, the pumping effect, and the signal response as a function of the film thickness were obtained. (C) 2011 Elsevier B.V. All rights reserved.

  17. Utilization of Neutron Bang-time CVD diamond detectors at the Z Accelerator

    Science.gov (United States)

    Chandler, Gordon; Hahn, Kelly; Ruiz, Carlos; Jones, Brent; Gomez, Matthew; Hess, Mark; Harding, Eric; Knapp, Patrick; Bur, James; Torres, Jose; Norris, Edward; Cooper, Gary; Styron, Jedediah; Moy, Ken; McKenna, Ian; Glebov, Vladimir; Fittinghoff, David; May, Mark; Snyder, Lucas

    2016-10-01

    We are utilizing Chemical Vapor Deposited (CVD) Diamond detectors at 2.3 meters on the Z accelerator to infer neutron bang-times from Magnetized Liner Inertial Fusion (MagLIF) sources yielding up to 3e12 DD neutrons and to bound the neutron time history of Deuterium Gas Puff loads producing 5e13 DD neutrons. The current implementation of the diagnostic and initial results will be shown as well as our future plans for the diagnostic. Sandia is sponsored by the U.S. DOE's NNSA under contract DE-AC04-94AL85000.

  18. Effect of substrate roughness on growth of diamond by hot filament CVD

    Indian Academy of Sciences (India)

    Awadesh K Mallik; S R Binu; L N Satapathy; Chandrabhas Narayana; Md Motin Seikh; S A Shivashankar; S K Biswas

    2010-06-01

    Polycrystalline diamond coatings are grown on Si (100) substrate by hot filament CVD technique. We investigate here the effect of substrate roughening on the substrate temperature and methane concentration required to maintain high quality, high growth rate and faceted morphology of the diamond coatings. It has been shown that as we increase the substrate roughness from 0.05 m to 0.91 m (centre line average or CLA) there is enhancement in deposited film quality (Raman peak intensity ratio of 3 to non-3 content increases from 1.65 to 7.13) and the substrate temperature can be brought down to 640°C without any additional substrate heating. The coatings grown at adverse conditions for 3 deposition has cauliflower morphology with nanocrystalline grains and coatings grown under favourable 3 condition gives clear faceted grains.

  19. Growth mechanisms and defects in boronated CVD diamond as identified by scanning tunneling microscopy

    Science.gov (United States)

    Kreutz, T. J.; Clausing, R. E.; Heatherly, L., Jr.; Warmack, R. J.; Thundat, T.; Feigerle, C. S.; Wandelt, K.

    1995-05-01

    Boron-doped CVD-diamond films were grown in a simple hot filament reactor. A set of samples grown using various methane-in-hydrogen concentrations has been examined by scanning tunneling microscopy in air. On the diamond (111) crystal faces monoatomic steps could be observed giving evidence for layer growth. At low CH4 concentrations the layers form triangular growth spirals. Screw dislocations in the middle of the spirals serve as continuous sources of steps for the layer growth producing (111) faces of high crystal perfection. At higher methane concentrations the crystal perfection declines and the (111) crystal faces exhibit a mosaic structure. The size of the subgrains in the mosaic pattern decreases with increasing CH4 concentration. Nucleation of new layers takes place at the subgrain boundaries. The topography of (001) crystal faces did not significantly change with the methane-in-hydrogen concentration and did not allow the determination of the underlying growth mechanism.

  20. Development of a CVD diamond Beam Condition Monitor for CMS at the Large Hadron Collider

    CERN Document Server

    Fernández-Hernando, L; Gray, R; Ilgner, C; MacPherson, A; Oh, A; Pritchard, T; Stone, R; Worm, S

    2005-01-01

    The CERN Large Hadron Collider (LHC) will store 2808 bunches per colliding beam, with each bunch consisting of 1011 protons at an energy of 7 TeV. If there is a failure in an element of the accelerator, the resulting beam losses could cause damage not only to the machine but also to the experiments. A Beam Condition Monitor (BCM) is foreseen to monitor fast increments of particle fluxes near the interaction point and, if necessary, to generate an abort signal to the LHC accelerator control to dump the beams. The system is being developed initially for the CMS experiment but it is sufficiently general to find potential applications elsewhere. Due to its high radiation hardness, CVD diamond was chosen for investigation as the BCM sensor. Various samples of CVD diamond have been characterized extensively with both a 90Sr source and in high-intensity test beams in order to assess the capabilities of such sensors and to study whether this detector technology is suitable for a BCM system. A selection of results fro...

  1. Fabrication and Characterization of FeNiCr Matrix-TiC Composite for Polishing CVD Diamond Film

    Institute of Scientific and Technical Information of China (English)

    Zhuji Jin; Zewei Yuan; Renke Kang; Boxian Dong

    2009-01-01

    Dynamic friction polishing (DFP) is one of the most promising methods appropriate for polishing CVD diamond film with high efficiency and low cost.By this method CVD diamond film is polished through being simply pressed against a metal disc rotating at a high speed utilizing the thermochemical reaction occurring as a result of dynamic friction between them in the atmosphere.However, the relatively soft materials such as stainless steel, cast iron and nickel alloy widely used for polishing CVD diamond film are easy to wear and adhere to diamond film surface, which may further lead to low efficiency and poor polishing quality.In this paper, FeNiCr matrix-TiC composite used as grinding wheel for polishing CVD diamond film was obtained by combination of mechanical alloying (MA) and spark plasma sintering (SPS).The process of ball milling,composition, density, hardness, high-temperature oxidation resistance and wear resistance of the sintered piece were analyzed.The results show that TiC was introduced in MA-SPS process and had good combination with FeNiCr matrix and even distribution in the matrix.The density of composite can be improved by mechanical alloying.The FeNiCr matrix-TiC composite obtained at 1273 K was found to be superior to at 1173 K sintering in hardness, high-temperature oxidation resistance and wearability.These properties are more favorable than SUS304 for the preparation of high-performance grinding wheel for polishing CVD diamond film.

  2. A Bayesian method to estimate the neutron response matrix of a single crystal CVD diamond detector

    Energy Technology Data Exchange (ETDEWEB)

    Reginatto, Marcel; Araque, Jorge Guerrero; Nolte, Ralf; Zbořil, Miroslav; Zimbal, Andreas [Physikalisch-Technische Bundesanstalt, D-38116 Braunschweig (Germany); Gagnon-Moisan, Francis [Paul Scherrer Institut, CH-5232 Villigen (Switzerland)

    2015-01-13

    Detectors made from artificial chemical vapor deposition (CVD) single crystal diamond are very promising candidates for applications where high resolution neutron spectrometry in very high neutron fluxes is required, for example in fusion research. We propose a Bayesian method to estimate the neutron response function of the detector for a continuous range of neutron energies (in our case, 10 MeV ≤ E{sub n} ≤ 16 MeV) based on a few measurements with quasi-monoenergetic neutrons. This method is needed because a complete set of measurements is not available and the alternative approach of using responses based on Monte Carlo calculations is not feasible. Our approach uses Bayesian signal-background separation techniques and radial basis function interpolation methods. We present the analysis of data measured at the PTB accelerator facility PIAF. The method is quite general and it can be applied to other particle detectors with similar characteristics.

  3. Superconductivity and low temperature electrical transport in B-doped CVD nanocrystalline diamond

    Directory of Open Access Journals (Sweden)

    Milos Nesladek, Jiri J. Mares, Dominique Tromson, Christine Mer, Philippe Bergonzo, Pavel Hubik and Jozef Kristofik

    2006-01-01

    Full Text Available In this work, we report on superconductivity (SC found in thin B-doped nanocrystalline diamond films, prepared by the PE-CVD technique. The thickness of the films varies from about 100 to 400 nm, the films are grown on low-alkaline glass at substrate temperatures of about 500–700 °C. The SIMS measurements show that films can be heavily doped with boron in concentrations in the range of 3×1021 cm−3. The Raman spectra show Fano resonances, confirming the substitutional B-incorporation. The low temperature magnetotransport measurements reveal a positive magnetoresistance. The SC transition is observed at about Tc=1.66 K. A simple theory exploiting the concept of weak localization accounting for this transition is proposed.

  4. Channeling Effect in Polycrystalline Deuterium-Saturated CVD Diamond Target Bombarded by Deuterium Ion Beam

    CERN Document Server

    Bagulya, A V; Negodaev, M A; Rusetskii, A S; Chubenko, A P; Ralchenko, V G; Bolshakov, A P

    2014-01-01

    At the ion accelerator HELIS at the LPI, the neutron yield is investigated in DD reactions within a polycrystalline deuterium-saturated CVD diamond, during an irradiation of its surface by a deuterium ion beam with the energy less than 30 keV. The measurements of the neutron flux in the beam direction are performed in dependence on the target angle, \\b{eta}, with respect to the beam axis. These measurements are performed using a multichannel detector based on He3 counters. A significant anisotropy in neutron yield is observed, it was higher by a factor of 3 at \\b{eta}=0 compared to that at \\b{eta} = +-45{\\deg}. The possible reasons for the anisotropy, including ion channeling, are discussed.

  5. Ultrasonic cavity preparation using CVD coated diamond bur: A case report.

    Science.gov (United States)

    de Vasconcellos, Beatriz Tholt; Thompson, Jeffrey Y; de Paula Macedo, Manoel Roberto; de Oliveira Maia, Janaína Monalisa; Oda, Margareth; Garone-Netto, Narciso

    2013-01-01

    Before any restorative procedure can be undertaken a proper cavity preparation is required. This clinical step is the mechanical alteration of the tooth to receive a restorative material with which a satisfactory form, function and the esthetics of the tooth will be established. In recent years improvements in materials and techniques have been devised and new technologies are now available for this purpose. The aim of the present study is to report two clinical cases in which a CVD coated diamond bur coupled to an ultrasonic handpiece is used in dental preparation. This technique provides an accurate and conservative tooth preparation with ideal access and visibility and because of enhanced efficiency can also play a role in eliminating some of the patient discomfort of the dental treatment.

  6. CO{sub 2} laser-induced plasma CVD synthesis of diamond

    Energy Technology Data Exchange (ETDEWEB)

    Konov, V.I.; Prokhorov, A.M.; Uglov, S.A.; Bolshakov, A.P.; Leontiev, I.A. [Rossijskaya Akademiya Nauk, Moscow (Russian Federation). Inst. Obshchej Fiziki; Dausinger, F.; Huegel, H.; Angstenberger, B. [Institute of High Power Beam Technology (IFSW), Stuttgart University, Pfaffenwaldring 43, D-70569 Stuttgart (Germany); Sepold, G.; Metev, S. [Bremen Institute of Applied Beam Technology, D-28800 Bremen 33, Klagenfurter Str. 2 (Germany)

    1998-05-01

    A novel technique for CVD synthesis of materials that does not demand a vacuum chamber and provides high deposition rates has been developed. It is based on CO{sub 2} laser maintenance of a stationary optical discharge in a gas stream, exhausting over a substrate into the air (laser plasmatron). Nano- and polycrystalline-diamond films were deposited on tungsten substrates from atmospheric-pressure Xe(Ar):H{sub 2}:CH{sub 4} gas mixtures at flow rates of 2 l/min. A 2.5-kW CO{sub 2} laser focused beam produced plasma. The deposition area was about 1 cm{sup 2} and growth rates were up to 30-50 {mu}m/h. Peculiarities and advantages of laser plasmatrons are discussed. (orig.) With 4 figs., 4 refs.

  7. Commissioning and first operation of the pCVD diamond ATLAS Beam Conditions Monitor

    CERN Document Server

    Dobos, D

    2009-01-01

    The main aim of the ATLAS Beam Conditions Monitor is to protect the ATLAS Inner Detector silicon trackers from high radiation doses caused by LHC beam incidents, e.g. magnet failures. The BCM uses in total 16 1x1 cm2 500 μm thick polycrystalline chemical vapor deposition (pCVD) diamond sensors. They are arranged in 8 positions around the ATLAS LHC interaction point. Time difference measurements with sub nanosecond resolution are performed to distinguish between particles from a collision and spray particles from a beam incident. An abundance of the latter leads the BCM to provoke an abort of the LHC beam. A FPGA based readout system with a sampling rate of 2.56 GHz performs the online data analysis and interfaces the results to ATLAS and the beam abort system. The BCM diamond sensors, the detector modules and their readout system are described. Results of the operation with the first LHC beams are reported and results of commissioning and timing measurements (e.g. with cosmic muons) in preparation for first ...

  8. Deep levels in CVD diamond and their influence on the electronic properties of diamond-based radiation sensors

    Energy Technology Data Exchange (ETDEWEB)

    Bruzzi, M.; Lagomarsino, S.; Menichelli, D.; Miglio, S.; Pini, S.; Sciortino, S. [Dipartimento di Energetica, Via S. Marta 3, 50139 Firenze (Italy); INFN, Sezione di Firenze (Italy); INFM, Sezione di Firenze (Italy); Bucciolini, M. [Dipartimento di Fisiopatologia Clinica, Firenze (Italy); INFN, Sezione di Firenze (Italy); Scaringella, M. [Dipartimento di Energetica, Via S. Marta 3, 50139 Firenze (Italy)

    2002-10-16

    Deep levels in undoped chemical vapor deposited (CVD) diamond films have been characterized by thermally stimulated current spectroscopy (TSC) in the range of 300-650 K. The TSC results have been tentatively correlated to the performance of the samples as on-line dosimeters and particle detectors. The TSC signal is dominated by a set of deep levels with an activation energy in the range of 1.0-1.4 eV. The trapping activity of these levels, which can be related to grain boundaries, strongly influences the detector performance at room temperature. After neutron irradiation up to the fluence of 2 x 10{sup 15} n/cm{sup 2} the amplitude of the TSC signal decreases of about one order of magnitude, the pumping effect becomes significantly less pronounced and the charge collection efficiency decreases of about 30%. Thus, the radiation-induced removal of these deep levels must be accompanied by the creation of other traps, probably vacancy-related and not visible by TSC in this temperature range, which have little effect on the dynamic response of the device but can affect the charge collection efficiency. (Abstract Copyright [2002], Wiley Periodicals, Inc.)

  9. Cutting characteristics of dental diamond burs made with CVD technology Características de corte de pontas odontológicas diamantadas obtidas pela tecnologia CVD

    Directory of Open Access Journals (Sweden)

    Luciana Monti Lima

    2006-04-01

    Full Text Available The aim of this study was to determine the cutting ability of chemical vapor deposition (CVD diamond burs coupled to an ultrasonic dental unit handpiece for minimally invasive cavity preparation. One standard cavity was prepared on the mesial and distal surfaces of 40 extracted human third molars either with cylindrical or with spherical CVD burs. The cutting ability was compared regarding type of substrate (enamel and dentin and direction of handpiece motion. The morphological characteristics, width and depth of the cavities were analyzed and measured using scanning electron micrographs. Statistical analysis using the Kruskal-Wallis test (p O objetivo deste estudo foi determinar a habilidade de corte das pontas de diamante obtidas pelo processo de deposição química a vapor (CVD associadas ao aparelho de ultra-som no preparo cavitário minimamente invasivo. Uma cavidade padronizada foi preparada nas faces mesial e distal de 40 terceiros molares, utilizando-se pontas de diamante CVD cilíndrica e esférica. A habilidade de corte foi comparada quanto ao tipo de substrato (esmalte e dentina e quanto à direção do movimento realizado com a ponta. As características morfológicas, a largura e profundidade das cavidades foram analisadas e medidas em microscopia eletrônica de varredura. A análise estatística pelo teste de Kruskal-Wallis (p < 0,05 revelou que a largura e profundidade das cavidades foram significativamente maiores em dentina. Cavidades mais largas foram obtidas quando se utilizou a ponta de diamante CVD cilíndrica, e mais profundas quando a ponta esférica foi empregada. A direção do movimento da ponta não influenciou o tamanho das cavidades, sendo os cortes produzidos pelas pontas de diamante CVD precisos e conservadores.

  10. Structural and optical characterization of thick and thin polycrystalline diamond films deposited by microwave plasma activated CVD

    Indian Academy of Sciences (India)

    S K Pradhan; B Satpati; B P Bag; T Sharda

    2012-02-01

    Preliminary results of growth of thin diamond film in a recently installed 3 kW capacity microwave plasma activated CVD (MW-PACVD) system are being reported. The films were deposited on Si (100) substrate at 850°C using methane and hydrogen mixture at 1.5 kW MW power. The grown polycrystalline films were characterized by micro-Raman, transmission electron microscope (TEM), spectrophotometer and atomic force microscope (AFM). The results were compared with that of a thicker diamond film grown elsewhere in a same make MWPACVD system at relatively higher power densities. The presence of a sharp Raman peak at 1332 cm-1 confirmed the growth of diamond, and transmission spectra showed typical diamond film characteristics in both the samples. Typical twin bands and also a quintuplet twinned crystal were observed in TEM, further it was found that the twinned region in thin sample composed of very fine platelet like structure.

  11. Atomic scale KMC simulation of {100} oriented CVD diamond film growth under low substrate temperature—Part Ⅰ Simulation of CVD diamond film growth under Joe-Badgwell-Hauge model

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The growth of {100} oriented CVD (Chemical Vapor Deposition)diamond film under Joe-Badgwell-Hauge (J-B-H) model is simulated at atomic scale by using revised KMC (Kinetic Monte Carlo) method. The results show that: (1) under Joe's model, the growth mechanism from single carbon species is suitable for the growth of {100} oriented CVD diamond film in low temperature; (2) the deposition rate and surface roughness () under Joe's model are influenced intensively by temperature ()and not evident bymass fraction of atom chlorine; (3)the surface roughness increases with the deposition rate, i.e. the film quality becomes worse with elevated temperature, in agreement with Grujicic's prediction; (4) the simulation results cannot make sure the role of single carbon insertion.

  12. Atomic scale KMC simulation of {100} oriented CVD diamond film growth under low substrate temperature—Part I simulation of CVD diamond film growth under Joe—Badgwell—Hauge model

    Institute of Scientific and Technical Information of China (English)

    Xizhong; YuZhang; 等

    2002-01-01

    The growth of {100} oriented CVD( Chemical Vapor Deposition) diamond film under Joe-Badgwell-Hauge(J-B-H) model is simulated at atomic scale by using revised KMC(Kinetic Monte Carlo)method.The results show that:(1) under Joe's model,the growth mechanism from single carbon species is suitable for the growth of {100} oriented CVD diamond film in low temperature;(2) the deposition rate and surface roughness(Rq) under Joe's model are influenced intensively by temperature(Ts) and not evident bymass fraction Wc1 of atom chlorine;(3) the surface roughness increases with the deposition rate.i.e.the film quality becomes worse with elevated temperature,in agreement with Grujicic's prediction;(4) the simulation results cannot make sure the role of single carbon insertion.

  13. Atomic scale KMC simulation of {100} oriented CVD diamond film growth under low substrate temperature-Part II Simulation of CVD diamond film growth in C-H system and in Cl-containing systems

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The growth of {100}-oriented CVD diamond film under two modifications of J-B-H model at low substrate temperatures was simulated by using a revised KMC method at atomic scale. The results were compared both in Cl-containing systems and in C-H system as follows: (1) Substrate temperature can produce an important effect both on film deposition rate and on surface roughness; (2) Aomic Cl takes an active role for the growth of diamond film at low temperatures; (3) {100}-oriented diamond film cannot deposit under single carbon insertion mechanism, which disagrees with the predictions before; (4) The explanation of the exact role of atomic Cl is not provided in the simulation results.

  14. Surface properties of diamond-like carbon films prepared by CVD and PVD methods

    Institute of Scientific and Technical Information of China (English)

    Liu Dong-Ping; Liu Yan-Hong; Chen Bao-Xiang

    2006-01-01

    Diamond-like carbon (DLC) films have been deposited using three different techniques: (a) electron cyclotron resonance-plasma source ion implantation, (b) low-pressure dielectric barrier discharge, (c) filtered-pulsed cathodic arc discharge. The surface and mechanical properties of these films are compared using atomic force microscopebased tests. The experimental results show that hydrogenated DLC films are covered with soft surface layers enriched with hydrogen and sp3 hybridized carbon while the soft surface layers of tetrahedral amorphous carbon (ta-C) films have graphite-like structure. The formation of soft surface layers can be associated with the surface diffusion and growth induced by the low-energy deposition process. For typical CVD methods, the atomic hydrogen in the plasmas can contribute to the formation of hydrogen and sp3 hybridized carbon enriched surface layers. The high-energy ion implantation causes the rearrangement of atoms beneath the surface layer and leads to an increase in film density. The ta-C films can be deposited using the medium energy carbon ions in the highly-ionized plasma.

  15. Optical and mechanical properties of diamond like carbon films deposited by microwave ECR plasma CVD

    Indian Academy of Sciences (India)

    S B Singh; M Pandey; N Chand; A Biswas; D Bhattacharya; S Dash; A K Tyagi; R M Dey; S K Kulkarni; D S Patil

    2008-10-01

    Diamond like carbon (DLC) films were deposited on Si (111) substrates by microwave electron cyclotron resonance (ECR) plasma chemical vapour deposition (CVD) process using plasma of argon and methane gases. During deposition, a d.c. self-bias was applied to the substrates by application of 13.56 MHz rf power. DLC films deposited at three different bias voltages (–60 V, –100 V and –150 V) were characterized by FTIR, Raman spectroscopy and spectroscopic ellipsometry to study the variation in the bonding and optical properties of the deposited coatings with process parameters. The mechanical properties such as hardness and elastic modulus were measured by load depth sensing indentation technique. The DLC film deposited at –100 V bias exhibit high hardness (∼ 19 GPa), high elastic modulus (∼ 160 GPa) and high refractive index (∼ 2.16–2.26) as compared to films deposited at –60 V and –150 V substrate bias. This study clearly shows the significance of substrate bias in controlling the optical and mechanical properties of DLC films.

  16. Luminescence and conductivity studies on CVD diamond exposed to UV light

    CERN Document Server

    Bizzarri, A; Bruzzi, M; Sciortino, S

    1999-01-01

    The photoluminescence (PL), thermoluminescence (TL) and thermally stimulated currents (TSC) of four high-quality CVD diamond films have been investigated in the range of temperatures between 300 and 700 K. The sample excitation has been carried out by means of an UV xenon lamp and UV laser lines. The features of the signals have been found equal to those obtained from particle excitation. The TL analysis shows the existence of several deep traps with activation energies between 0.6 and 1.0 eV. The contribution to the TL signal from different traps has been singled out by means of successive annealing processes. The TL results are in good agreement with those obtained from TSC measurements. The combined use of the two techniques allows a precise determination of the trap parameters. The spectral content of the TL response has also been compared with the PL signal in order to investigate the recombination process. This analysis shows that, in this temperature range, the TL signal is likely due to recombination ...

  17. Luminescence and conductivity studies on CVD diamond exposed to UV light

    Science.gov (United States)

    Bizzarri, A.; Bogani, F.; Bruzzi, M.; Sciortino, S.

    1999-04-01

    The photoluminescence (PL), thermoluminescence (TL) and thermally stimulated currents (TSC) of four high-quality CVD diamond films have been investigated in the range of temperatures between 300 and 700 K. The sample excitation has been carried out by means of an UV xenon lamp and UV laser lines. The features of the signals have been found equal to those obtained from particle excitation. The TL analysis shows the existence of several deep traps with activation energies between 0.6 and 1.0 eV. The contribution to the TL signal from different traps has been singled out by means of successive annealing processes. The TL results are in good agreement with those obtained from TSC measurements. The combined use of the two techniques allows a precise determination of the trap parameters. The spectral content of the TL response has also been compared with the PL signal in order to investigate the recombination process. This analysis shows that, in this temperature range, the TL signal is likely due to recombination from bound states rather than due to radiative free to bound transitions, as generally assumed in TL theory. The TSC signal is likely to arise from impurity band rather than from free carriers conduction.

  18. The High performance of nanocrystalline CVD diamond coated hip joints in wear simulator test.

    Science.gov (United States)

    Maru, M M; Amaral, M; Rodrigues, S P; Santos, R; Gouvea, C P; Archanjo, B S; Trommer, R M; Oliveira, F J; Silva, R F; Achete, C A

    2015-09-01

    The superior biotribological performance of nanocrystalline diamond (NCD) coatings grown by a chemical vapor deposition (CVD) method was already shown to demonstrate high wear resistance in ball on plate experiments under physiological liquid lubrication. However, tests with a close-to-real approach were missing and this constitutes the aim of the present work. Hip joint wear simulator tests were performed with cups and heads made of silicon nitride coated with NCD of ~10 μm in thickness. Five million testing cycles (Mc) were run, which represent nearly five years of hip joint implant activity in a patient. For the wear analysis, gravimetry, profilometry, scanning electron microscopy and Raman spectroscopy techniques were used. After 0.5 Mc of wear test, truncation of the protruded regions of the NCD film happened as a result of a fine-scale abrasive wear mechanism, evolving to extensive plateau regions and highly polished surface condition (Ra<10nm). Such surface modification took place without any catastrophic features as cracking, grain pullouts or delamination of the coatings. A steady state volumetric wear rate of 0.02 mm(3)/Mc, equivalent to a linear wear of 0.27 μm/Mc favorably compares with the best performance reported in the literature for the fourth generation alumina ceramic (0.05 mm(3)/Mc). Also, squeaking, quite common phenomenon in hard-on-hard systems, was absent in the present all-NCD system.

  19. Surface morphology, growth rate and quality of diamond films synthesized in hot filament CVD system under various methane concentrations

    Science.gov (United States)

    Ali, M.; Ürgen, M.

    2011-08-01

    Hot filament chemical vapor deposition (CVD) technique has been used to deposit diamond films on silicon substrate. In the present study, diamond films were grown at various vol.% CH 4 in H 2 from 0.5% to 3.5%, at substrate temperature and pressure of 850 °C and 80 torr, respectively. Scanning electron microscopy, X-ray diffraction and Raman spectroscopy were employed to analyze the properties of deposited films. The formation of methyl radicals as a function of vol.% CH 4 not only changes film morphology but also increase film growth rate. At low, intermediate and high vol.% CH 4, cluster, faceted cubes and pyramidal features growth, were dominant. By increasing vol.% CH 4 from 0.5% to 3.5%, as the growth rate improved from ˜0.25 μm/h to ˜2.0 μm/h. Raman studies features revealed high purity diamond films at intermediate range of vol.% CH 4 and grain density increased by increasing CH 4 concentration. The present study represents experimentally surface morphology, growth rate and quality of diamond films grown in hot filament CVD system at various CH 4 concentrations.

  20. Multilayer CVD Diamond Coatings in the Machining of an Al6061-15 Vol % Al2O3 Composite

    Directory of Open Access Journals (Sweden)

    Mohammadmehdi Shabani

    2017-10-01

    Full Text Available Ceramic cutting inserts coated with ten-fold alternating micro- and nanocrystalline diamond (MCD/NCD layers grown by hot filament chemical vapor deposition (CVD were tested in the machining of an Al based metallic matrix composite (MMC containing 15 vol % Al2O3 particles. Inserts with total coating thicknesses of approximately 12 µm and 24 µm were produced and used in turning: cutting speed (v of 250 to 1000 m·min−1; depth of cut (DOC from 0.5 to 3 mm and feed (f between 0.1 and 0.4 mm·rev−1. The main cutting force increases linearly with DOC (ca. 294 N per mm and with feed (ca. 640 N per mm·rev−1. The thicker coatings work within the following limits: DOC up to 1.5 mm and maximum speeds of 750 m·min−1 for feeds up to 0.4 mm·rev−1. Flank wear is predominant but crater wear is also observed due to the negative tool normal rake. Layer-by-layer wear of the tool rake, and not total delamination from the substrate, evidenced one of the advantages of using a multilayer design. The MCD/NCD multilayer diamond coated indexable inserts have longer tool life than most CVD diamond systems and behave as well as most polycrystalline diamond (PCD tools.

  1. Morphology of Diamond Layers Grown on Different Facets of Single Crystal Diamond Substrates by a Microwave Plasma CVD in CH4-H2-N2 Gas Mixtures

    Directory of Open Access Journals (Sweden)

    Evgeny E. Ashkinazi

    2017-06-01

    Full Text Available Epitaxial growth of diamond films on different facets of synthetic IIa-type single crystal (SC high-pressure high temperature (HPHT diamond substrate by a microwave plasma CVD in CH4-H2-N2 gas mixture with the high concentration (4% of nitrogen is studied. A beveled SC diamond embraced with low-index {100}, {110}, {111}, {211}, and {311} faces was used as the substrate. Only the {100} face is found to sustain homoepitaxial growth at the present experimental parameters, while nanocrystalline diamond (NCD films are produced on other planes. This observation is important for the choice of appropriate growth parameters, in particular, for the production of bi-layer or multilayer NCD-on-microcrystalline diamond (MCD superhard coatings on tools when the deposition of continuous conformal NCD film on all facet is required. The development of the film morphology with growth time is examined with SEM. The structure of hillocks, with or without polycrystalline aggregates, that appear on {100} face is analyzed, and the stress field (up to 0.4 GPa within the hillocks is evaluated based on high-resolution mapping of photoluminescence spectra of nitrogen-vacancy NV optical centers in the film.

  2. Continuous observation of polarization effects in thin SC-CVD diamond detector designed for heavy ion microbeam measurement

    Energy Technology Data Exchange (ETDEWEB)

    Kada, Wataru, E-mail: kada.wataru@gunma-u.ac.jp [Faculty of Science and Technology, Gunma University, 1-5-1 Tenjin-machi, Kiryu, Gunma 376-8515 (Japan); Iwamoto, Naoya [Quantum Beam Science Directorate, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Satoh, Takahiro [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Onoda, Shinobu [Quantum Beam Science Directorate, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Grilj, Veljko; Skukan, Natko [Ruđer Bošković Institute, P.O. Box 1016, 10001 Zagreb (Croatia); Koka, Masashi [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Ohshima, Takeshi [Quantum Beam Science Directorate, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Jakšić, Milko [Ruđer Bošković Institute, P.O. Box 1016, 10001 Zagreb (Croatia); Kamiya, Tomihiro [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan)

    2014-07-15

    Continuous irradiation effects on a thin-film diamond detector were investigated for the utilization of these films as a detector for heavy ion microbeams. Temporal signal degradation in the energy spectrum was frequently observed during the focused heavy ion microbeam irradiation. To measure the temporal response to the each ion incidents, focused heavy ion microbeam with different beam fluence rates were irradiated to a single crystal (SC)-CVD diamond film detector with thickness of 50 μm. The responses to each ion were continuously observed and characterized by ion beam-induced charge (IBIC) measurement system. Heavy ions with short penetration path in diamond generate the large difference in mean path of electrons and holes, which is inverted by changing bias polarity. Signal degradation condition was relied on the bias polarity under the irradiation of heavy ions with short penetration length in the diamond. The continuous observation of IBIC signals revealed that temporal degradation in pulse height of signals, so called polarization effects, seems to be mainly caused by the hole trapping in this diamond crystal.

  3. Electronic properties of single crystal CVD diamond and its suitability for particle detection in hadron physics experiments

    Energy Technology Data Exchange (ETDEWEB)

    Pomorski, Michal

    2008-08-07

    This work presents the study on the suitability of single-crystal CVD diamond for particle-detection systems in present and future hadron physics experiments. Different characterization methods of the electrical and the structural properties were applied to gain a deeper understanding of the crystal quality and the charge transport properties of this novel semiconductor material. First measurements regarding the radiation tolerance of diamond were performed with sensors heavily irradiated with protons and neutrons. Finally, detector prototypes were fabricated and successfully tested in various experiments as time detectors for minimum ionizing particles as well as for spectroscopy of heavy ions at the energy ranges available at the SIS and the UNILAC facilities of GSI. (orig.)

  4. Structure and wettability property of the growth and nucleation surfaces of thermally treated freestanding CVD diamond films

    Science.gov (United States)

    Pei, Xiaoqiang; Cheng, Shaoheng; Ma, Yibo; Wu, Danfeng; Liu, Junsong; Wang, Qiliang; Yang, Yizhou; Li, Hongdong

    2015-08-01

    This paper reports the surface features and wettability properties of the (1 0 0)-textured freestanding chemical vapor deposited (CVD) diamond films after thermal exposure in air at high temperature. Thermal oxidation at proper conditions eliminates selectively nanodiamonds and non-diamond carbons in the films. The growth side of the films contains (1 0 0)-oriented micrometer-sized columns, while its nucleation side is formed of nano-sized tips. The examined wettability properties of the as-treated diamond films reveal a hydrophilicity and superhydrophilicity on the growth surface and nucleation surface, respectively, which is determined by oxygen termination and geometry structure of the surface. When the surface termination is hydrogenated, the wettability of nucleation side converted from superhydrophilicity to high hydrophobicity, while the hydrophilicity of the growth side does not change significantly. The findings open a possibility for realizing freestanding diamond films having not only novel surface structures but also multifunction applications, especially proposed on the selected growth side or nucleation side in one product.

  5. Excitonic emission and N- and B-incorporation in homoepitaxial CVD-grown diamond investigated by cathodoluminescence

    Science.gov (United States)

    Araujo, D.; Kadri, M.; Wade, M.; Bustarret, E.; Deneuville, A.

    2005-03-01

    Diamond is a very large bandgap material arising high expectations either for optoelectronic applications or for active semiconducting layers in specific electronic devices to be used under extreme conditions of pressure, temperature, wear or radiation, as well as in chemically aggressive environments. Unintentionally boron-doped diamond layers were grown by microwave plasma-assisted chemical vapour deposition (CVD) on {001}-oriented undoped Ib substrates with the addition of oxygen gas during growth. The relative quantities of nitrogen and boron incorporated in the diamond lattice are evaluated by cathodoluminescence (CL) spectra recorded at 5 K. Two different effects are shown to limit nitrogen incorporation: the substrate crystalline quality and the addition of oxygen into the precursor during the growth. First, the CL spectra are shown to change strongly near the edges of the substrate in the regions corresponding to different bulk crystal growth modes. Some regions show a luminescence governed by UV emission while in other regions, where the H3 defect-related luminescence of the substrate is much stronger, the film UV emission is reduced. Second, the relative importance of the free exciton emission with respect to those from the nitrogen-related H3 centre and from the boron-bound exciton is shown to increase with the addition of oxygen during growth. Such observations are of first importance to improve the spectral emission and absorption threshold of the diamond material in the deep UV range.

  6. The effectiveness of Ti implants as barriers to carbon diffusion in Ti implanted steel under CVD diamond deposition conditions

    Energy Technology Data Exchange (ETDEWEB)

    Weiser, P.S.; Prawer, S. [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Hoffman, A. [Technion-Israel Inst. of Tech., Haifa (Israel). Dept. of Chemistry; Evan, P.J. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Paterson, P.J.K. [Royal Melbourne Inst. of Tech., VIC (Australia)

    1993-12-31

    The growth of chemical vapour deposited (CVD) diamond onto iron based substrates complicated by preferential soot formation and carbon diffusion into the substrate [1], leading to poor quality films and poor adhesion. In the initial stages of exposure to a microwave plasma, a layer of graphite is rapidly formed on an untreated Fe based substrate. Once this graphite layer reaches a certain thickness, reasonable quality diamond nucleates and grows upon it. However, the diamond film easily delaminates from the substrate, the weak link being the graphitic layer. Following an initial success in using a TiN barrier layer to inhibit the formation of such a graphitic layer the authors report on attempts to use an implanted Ti layer for the same purpose. This work was prompted by observation that, although the TiN proved to be an extremely effective diffusion barrier, adhesion may be further enhanced by the formation of a TiC interface layer between the diamond film and the Fe substrate. 3 refs., 6 figs.

  7. Diamond films grown without seeding treatment and bias by hot-filament CVD system

    Science.gov (United States)

    Ali, M.; Ürgen, M.

    2012-04-01

    Diamond film growth without seeding treatment has been the subject of numerous studies. In the present study, diamond films with/without seeding treatment were grown on silicon using hot-filament chemical vapour deposition. An inexpensive and simple approach, namely, "dry ultrasonic treatment", was introduced in which full coverage of diamond film was achieved on unseeded substrate. For comparison, one substrate was seeded with 5 μm diamond particles, prior to deposition. The resulting diamond films were examined through standard characterization tools and distinct features were observed in each film. Here we present the results of uniform and high purity diamond film, free from nano-sized grains, which is grown without seeding treatment and is expected to be potential candidate for electro-optical applications, particularly as heat sinks.

  8. Selective growth of diamond by hot filament CVD using patterned carbon film as mask

    Institute of Scientific and Technical Information of China (English)

    HE Zhoutong; YANG Shumin; LI Qintao; ZHU Dezhang; GONG Jinlong

    2008-01-01

    Selected-area deposition (SAD) of diamond films was achieved on silicon substrates with carbon film mask by hot filament chemical vapor deposition. Needle tip scraped lines were used to grow diamond films. Scanning electron microscope (SEM) investigation demonstrates that highly selective and sharp edged diamond films were produced. The results also demonstrate that the proper substrate temperature is very important for diamond selective growth in this deposition process. Since the enhancement of diamond growth was not observed on the needle tip scraped area of Si wafer with diamond powder scratching, the selective growth was considered to be closely correlated to silicon carbide formed during carbon film deposition and the residual carbon in the scraped area.

  9. Superconductivity in CVD Diamond Thin Film Well-Above Liquid Helium Temperature

    OpenAIRE

    Takano, Y.; Nagao, M.; Kobayashi, K; Umezawa, H.; Sakaguchi, I.; Tachiki, M.; Hatano, T.; Kawarada, H.

    2004-01-01

    Diamond has always been adored as a jewel. Even more fascinating is its outstanding physical properties; it is the hardest material known in the world with the highest thermal conductivity. Meanwhile, when we turn to its electrical properties, diamond is a rather featureless electrical insulator. However, with boron doping, it becomes a p-type semiconductor, with boron acting as a charge acceptor. Therefore the recent news of superconductivity in heavily boron-doped diamond synthesized by hig...

  10. Radiation hardness of a single crystal CVD diamond detector for MeV energy protons

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Yuki, E-mail: y.sato@riken.jp [The Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Shimaoka, Takehiro; Kaneko, Junichi H. [Graduate School of Engineering, Hokkaido University, N13, W8, Sapporo 060-8628 (Japan); Murakami, Hiroyuki [The Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Isobe, Mitsutaka; Osakabe, Masaki [National Institute for Fusion Science, 322-6, Oroshi-cho Toki-city, Gifu 509-5292 (Japan); Tsubota, Masakatsu [Graduate School of Engineering, Hokkaido University, N13, W8, Sapporo 060-8628 (Japan); Ochiai, Kentaro [Fusion Research and Development Directorate, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Chayahara, Akiyoshi; Umezawa, Hitoshi; Shikata, Shinichi [National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577 (Japan)

    2015-06-01

    We have fabricated a particle detector using single crystal diamond grown by chemical vapor deposition. The irradiation dose dependence of the output pulse height from the diamond detector was measured using 3 MeV protons. The pulse height of the output signals from the diamond detector decreases as the amount of irradiation increases at count rates of 1.6–8.9 kcps because of polarization effects inside the diamond crystal. The polarization effect can be cancelled by applying a reverse bias voltage, which restores the pulse heights. Additionally, the radiation hardness performance for MeV energy protons was compared with that of a silicon surface barrier detector.

  11. High-temperature characteristics of charge collection efficiency using single CVD diamond detectors

    Energy Technology Data Exchange (ETDEWEB)

    Tsubota, Masakatsu, E-mail: tsubota@eng.hokudai.ac.jp [Graduate School of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo 060-8628 (Japan); Kaneko, Junichi H.; Miyazaki, Daijirou; Shimaoka, Takehiro [Graduate School of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo 060-8628 (Japan); Ueno, Katsunori; Tadokoro, Takahiro [Hitachi Research Laboratory, Hitachi, Ltd., 2-1, Omika, 7-chome, Hitachi 319-1221, Ibaraki (Japan); Chayahara, Akiyoshi [Research Institute for Ubiquitous Energy Devices, National Institute of Advanced Industrial Science and Technology, 1-8-31, Midorigaoka, Ikeda 563-8577, Osaka (Japan); Watanabe, Hideyuki; Kato, Yukako; Shikata, Shin-ichi [Research Institute for Electronics and Photonics, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba 305-8562, Ibaraki (Japan); Kuwabara, Hitoshi [Infrastructure Systems Co., Hitachi, Ltd., 2-1, Omika-cho, 5-chome, Hitachi 319-1293, Ibaraki (Japan)

    2015-07-21

    We synthesized single-crystal diamonds using microwave assisted plasma chemical vapor deposition and evaluated the temperature dependence of the diamond radiation detectors. We achieved charge collection efficiency of the hole of 96.9% with 3.0% energy resolution at 473 K. In the case of electrons, they became undetectable at temperatures higher than 373 K. It is possible that carrier trapping generated with frequency or the leakage current increased. The detector produced by the diamond in Diamond Detector Ltd. detector, operates normally at 523 K. Electrons can be measured at 573 K. We discussed the characteristics of charge carrier transport in the diamond detector to prepare for future use at higher temperatures. - Highlights: • We synthesized single-crystal diamonds and made the sandwich type detector. • Charge collection efficiency of the hole of 97% was achieved at high-temperature. • The radiation detector of the purchased diamond was stable operation at 573 K. • Increase of carrier trapping and the leakage current were the essential problems. • This study ascertains the current state of the art of diamond detectors.

  12. High-order Stokes and anti-Stokes Raman generation in monoisotopic CVD {sup 12}C-diamond

    Energy Technology Data Exchange (ETDEWEB)

    Kaminskii, Alexander A. [Institute of Crystallography, Russian Academy of Sciences, Moscow (Russian Federation); Lux, Oliver; Rhee, Hanjo; Eichler, Hans J. [Institute of Optics and Atomic Physics, Technische Universitaet Berlin (Germany); Ralchenko, Victor G.; Bolshakov, Andrey P. [General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Shirakawa, Akira; Yoneda, Hitoki [Institute for Laser Science, University of Electro-Communications, Tokyo (Japan)

    2016-06-15

    We determined, for the first time, the room temperature phonon energy related to the F{sub 2g} vibration mode (ω{sub SRS(12C)} ∝ 1333.2 cm{sup -1}) in a mono-crystalline single-isotope CVD {sup 12}C-diamond crystal by means of stimulated Raman scattering (SRS) spectroscopy. Picosecond one-micron excitation using a Nd{sup 3+}:Y{sub 3}Al{sub 5}O{sub 12}-laser generates a nearly two-octave spanning SRS frequency comb (∝12000 cm{sup -1}) consisting of higher-order Stokes and anti-Stokes components. The spacing of the spectral lines was found to differ by Δω{sub SRS} ∝ 0.9 cm{sup -1} from the comb spacing (ω{sub SRS(natC)} ∝ 1332.3 cm{sup -1}) when pumping a conventional CVD diamond crystal with a natural composition of the two stable carbon isotopes {sup 12}C (98.93%) and {sup 13}C (1.07%). (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Development of a Beam Condition Monitor System for the Experimental Areas of the LHC Using CVD Diamond

    CERN Document Server

    Fernández-Hernando, L

    2004-01-01

    The CERN Large Hadron Collider (LHC) will store 2808 bunches per colliding beam, each bunch consisting of 10^11 protons at an energy of 7 TeV. If there is a failure in an element of the accelerator, the resulting beam losses could cause damages not only to the machine but also to the experiments. A Beam Condition Monitor (BCM) is foreseen to monitor fast increments of particle fluxes near the interaction point and, if necessary, to generate an abort signal to the LHC accelerator control to dump the beams. The system is being developed initially for the CMS experiment but is sufficiently general to find potential applications elsewhere. Due to its high radiation hardness, CVD diamond has been studied for use as the BCM sensor. Various samples of CVD diamond have been characterized extensively with a Sr-90 source and high intensity test beams in order to assess the capabilities of such sensors and to study whether this detector technology is suitable for a BCM system. The results from these investigations are p...

  14. Novel Diamond Films Synthesis Strategy: Methanol and Argon Atmosphere by Microwave Plasma CVD Method Without Hydrogen

    Science.gov (United States)

    Yang, Li; Jiang, Caiyi; Guo, Shenghui; Zhang, Libo; Gao, Jiyun; Peng, Jinhui; Hu, Tu; Wang, Liang

    2016-09-01

    Diamond thin films are grown on silicon substrates by only using methanol and argon mixtures in microwave plasma chemical vapor deposition (MPCVD) reactor. It is worth mentioning that the novel strategy makes the synthesis reaction works smoothly without hydrogen atmosphere, and the substrates temperature is only 500 °C. The evidence of surface morphology and thickness under different time is obtained by characterizing the samples using scanning electron microscopy (SEM). X-ray diffractometer (XRD) spectrum reveals that the preferential orientation of (111) plane sample is obtained. The Raman spectra indicate that the dominant component of all the samples is a diamond. Moreover, the diamond phase content of the targeted films was quantitatively analyzed by X-ray photoelectron spectroscopy (XPS) method, and the surface roughness of diamond films was investigated by atomic force microscope (AFM). Meanwhile, the possible synthesis mechanism of the diamond films in methanol- and argon-mixed atmosphere was discussed.

  15. Optical characterization and thermal properties of CVD diamond films for integration with power electronics

    Science.gov (United States)

    Nazari, Mohammad; Hancock, B. Logan; Anderson, Jonathan; Hobart, Karl D.; Feygelson, Tatyana I.; Tadjer, Marko J.; Pate, Bradford B.; Anderson, Travis J.; Piner, Edwin L.; Holtz, Mark W.

    2017-10-01

    Studies of diamond material for thermal management are reported for a nominally 1-μm thick layer grown on silicon. Thickness of the diamond is measured using spectroscopic ellipsometry. Spectra are consistently modeled using a diamond layer taking into account surface roughness and requiring an interlayer of nominally silicon carbide. The presence of the interlayer is confirmed by transmission electron microscopy. Thermal conductivity is determined based on a heater which is microfabricated followed by back etching to produce a supported diamond membrane. Micro-Raman mapping of the diamond phonon is used to estimate temperature rise under known drive conditions of the resistive heater. Consistent values are obtained for thermal conductivity based on straightforward analytical calculation using phonon shift to estimate temperature and finite element simulations which take both temperature rise and thermal stress into account.

  16. A new CVD Diamond Mosaic-Detector for (n,$\\alpha$) Cross-Section Measurements at the n_TOF Experiment at CERN

    CERN Document Server

    Weiss, C; Guerrero, C; Altstadt, S; Andrzejewski, J; Audouin, L; Badurek, G; Barbagallo, M; Becares, V; Becvar, F; Belloni, F; Berthoumieux, E; Billowes, J; Boccone, V; Bosnar, D; Brugger, M; Calviani, M; Calvino, F; Cano-Ott, D; Carrapico, C; Cerutti, F; Chiaveri, E; Chin, M; Colonna, N; Cortes, G; Cortes-Giraldo, M.A; Diakaki, M; Domingo-Pardo, C; Duran, I; Dressler, R; Dzysiuk, N; Eleftheriadis, C; Ferrari, A; Fraval, K; Ganesan, S; Garcia, A.R; Giubrone, G; Gomez-Hornillos, M.B; Goncalves, I.F; Gonzalez-Romero, E; Gunsing, F; Gurusamy, P; Hernandez-Prieto, A; Jenkins, D.G; Jericha, E; Kadi, Y; KäPpeler, F; Karadimos, D; Kivel, N; Koehler, P; Kokkoris, M; Krticka, M; Kroll, J; Lampoudis, C; Langer, C; Leal-Cidoncha, E; Lederer, C; Leeb, H; Leong, L.S; Losito, R; Mallick, A; Manousos, A; Marganiec, J; Martinez, T; Massimi, C; Mastinu, P.F; Mastromarco, M; Meaze, M; Mendoza, E; Mengoni, A; Milazzo, P.M; Mingrone, F; Mirea, M; Mondalaers, W; Paradela, C; Pavlik, A; Perkowski, J; Plompen, A; Praena, J; Quesada, J.M; Rauscher, T; Reifarth, R; Riego, A; Robles, M.S; Roman, F; Rubbia, C; Sabate-Gilarte, M; Sarmento, R; Saxena, A; Schillebeeckx, P; Schmidt, S; Schumann, D; Tagliente, G; Tain, J.L; Tarrio, D; Tassan-Got, L; Tsinganis, A; Valenta, S; Vannini, G; Variale, V; Vaz, P; Ventura, A; Versaci, R; Vermeulen, M.J; Vlachoudis, V; Vlastou, R; Wallner, A; Ware, T; Weigand, M; Wright, T; Zugec, P

    2013-01-01

    At the n_TOF experiment at CERN a dedicated single-crystal chemical vapor deposition (sCVD) Diamond Mosaic-Detector has been developed for (n,$\\alpha$) cross-section measurements. The detector, characterized by an excellent time and energy resolution, consists of an array of 9 sCVD diamond diodes. The detector has been characterized and a cross-section measurement has been performed for the $^{59}$Ni(n,$\\alpha$)$^{56}$Fe reaction in 2012. The characteristics of the detector, its performance and the promising preliminary results of the experiment are presented.

  17. Oxidative Degradation of High Quality CVD Diamond%高质量CVD金刚石膜的氧化损伤

    Institute of Scientific and Technical Information of China (English)

    刘敬明; 唐伟忠; 吕反修

    2001-01-01

    Studies of the oxidative degradation of high quality diamond have been conducted to better define the limits of application at high temperature.The infrared(IR)and visible optical performance of polished chemical vapor deposition (CVD) diamond films were degraded seriously after heating at 780℃ for 15min,while heating at 780℃ for 3 min produced a little change .Microscopic etched features were revealed by scanning electron microscopy(SEM),atomic force microscopy (AFM),and Talystep surface profiles.Many of the etched features are concentrated at a variety of defects including grain boundaries,surface porosity etc. The results of heating are increasing the surface roughness of CVD diamond films and degradation of the infrared transmittance.%高质量CVD金刚石膜的高温损伤的研究是其高温应用的基础。抛光的金刚石膜经780℃保温3min后,红外透过和可见光的透过率开始下降;780℃保温15min后,其红外透过和可见光的透过率严重受损。扫描电镜、原子力学显微镜及台阶仪的结果表明:CVD金刚石膜氧化的开始阶段主要集中在晶界、表面孔洞等缺陷处,随后导致金刚石膜的晶面也开始刻蚀,表面粗糙度增大,最终使得金刚石膜丧失红外和可见光的透过。

  18. Influence of intermittently etching on quality of CVD diamond thin films

    Institute of Scientific and Technical Information of China (English)

    YANG Kan-cheng; XIA Yi-ben; WANG Lin-jun; LIU Jian-min; SU Qing-feng; XU Run; PENG Hong-yan; SHI Wei-min

    2006-01-01

    A new method,called growing-etching repetitional process based on hot filament chemical vapor deposition,was proposed to improve the quality of diamond film. During the deposition carbon source was intermittently closed letting hydrogen etch the surface of the diamond film from time to time. In order to find whether it is helpful to the films' quality,a series of experiments were done. The results show that the new method can enhance the orientation of the chemical vapor deposition diamond films,reduce the graphite phase and increase the film's surface resistivity.

  19. X-ray beam monitor made by thin-film CVD single-crystal diamond.

    Science.gov (United States)

    Marinelli, Marco; Milani, E; Prestopino, G; Verona, C; Verona-Rinati, G; Angelone, M; Pillon, M; Kachkanov, V; Tartoni, N; Benetti, M; Cannatà, D; Di Pietrantonio, F

    2012-11-01

    A novel beam position monitor, operated at zero bias voltage, based on high-quality chemical-vapor-deposition single-crystal Schottky diamond for use under intense synchrotron X-ray beams was fabricated and tested. The total thickness of the diamond thin-film beam monitor is about 60 µm. The diamond beam monitor was inserted in the B16 beamline of the Diamond Light Source synchrotron in Harwell (UK). The device was characterized under monochromatic high-flux X-ray beams from 6 to 20 keV and a micro-focused 10 keV beam with a spot size of approximately 2 µm × 3 µm square. Time response, linearity and position sensitivity were investigated. Device response uniformity was measured by a raster scan of the diamond surface with the micro-focused beam. Transmissivity and spectral responsivity versus beam energy were also measured, showing excellent performance of the new thin-film single-crystal diamond beam monitor.

  20. The Formation of Nanocrystalline Diamond Coating on WC Deposited by Microwave Assisted Plasma CVD

    Science.gov (United States)

    Toff, M. R. M.; Hamzah, E.; Purniawan, A.

    2010-03-01

    Diamond is one form of carbon structure. The extreme hardness and high chemical resistant of diamond coatings determined that many works on this area relate to coated materials for tribological applications in biomedicine, as mechanical seals or cutting tools for hard machining operations. In the work, nanocrystalline diamond (NCD) coated tungsten carbide (WC) have been deposited by microwave assisted plasma chemical vapor deposition (MAPCVD) from CH4/H2 mixtures. Morphology of NCD was investigated by using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The quality of NCD is defined as ratio between diamond and non diamond and also full width at half maximum (FWHM) was determined using Raman spectra. The result found that the NCD structure can be deposited on WC surface using CH4/H2 gas mixture with grain size ˜20 nm to 100 nm. Increase %CH4 concentration due to increase the nucleation of NCD whereas decrease the quality of diamond. Based on Raman spectra, the quality of NCD is in the range ˜98.82-99.01% and 99.56-99.75% for NCD and microcrystalline (MCD), respectively. In addition, FWHM of NCD is high than MCD in the range of 8.664-62.24 cm-1 and 4.24-5.05 cm-1 for NCD and MCD respectively that indicate the crystallineity of NCD is smaller than MCD.

  1. Can surface preparation with CVD diamond tip influence on bonding to dental tissues?

    Science.gov (United States)

    Aparecido Kawaguchi, Fernando; Brossi Botta, Sergio; Nilo Vieira, Samuel; Steagall Júnior, Washington; Bona Matos, Adriana

    2008-04-01

    This study evaluated the influence of chemical vapor deposition (CVD) tips surface treatments of enamel and dentin on bonding resistance of two adhesive systems. Thirty embedded samples were divided in 12 groups ( n = 10), according to factors: substrate (enamel and dentin), adhesive system [etch-and-rinse (SB) and self-etch]; and the surface treatments (paper discs, impact CVD tips and tangential CVD tip). When CVD tip was used in the impact mode the tip was applied perpendicular to dental surface, while at tangential mode, the tip worked parallel to dental surface. Specimens were tested in tension after 24 h at 0.5 mm/min of cross-head speed. ANOVA results, in MPa showed that in enamel, only adhesive system factor was statistically significant ( p = 0.015) under tested conditions, with higher bond strength observed for SB groups. However, in dentin the best bonding performance was obtained in SE groups ( p = 0.00). In both tested substrates, results did not show statistically significant difference for factors treatment and its interactions. ConclusionsIt may be concluded that CVD-tip surface treatment, in both tested modes, did not influence on adhesion to enamel and dentin. But, it is important to choose adhesive system according to the tissue available to bonding.

  2. High-Productivity Ultraprecise Polishing Technique of CVD Diamond Film%CVD金刚石膜高效超精密抛光技术

    Institute of Scientific and Technical Information of China (English)

    苑泽伟; 金洙吉; 王坤; 温泉

    2011-01-01

    CVD diamond film, as the material for optical transmission windows and new-generation computer chips, is required to be fine polished. However, there is so far no individual method which can polish CVD diamond film with both high efficiency and fine polishing quality. This paper attempted to polish CVD diamond film by combining chemical mechanical polishing (CMP) method and mechanical polishing method. CVD diamond film was first polished by fixed abrasive and free diamond abrasive to remove course asperities, and subsequently polished by CMP to achieve fine surface. According to the experimental results, the material removal rate achieved by free diamond abrasive is much higher than that by fixed abrasive. The surface roughness of CVD diamond film polished by free diamond abrasive is about 42. 2 nm. Fine surface quality of CVD diamond film was achieved by CMP and the surface roughness is about 4. 551 nm.%CVD金刚石膜作为光学透射窗口和新一代计算机芯片的材料,其表面必须得到高质量抛光,但是现存方法难以满足既高效又超精密的加工要求.本文提出机械抛光与化学机械抛光相结合的方法.首先,采用固结金刚石磨料抛光盘和游离金刚石磨料两种机械抛光方法对CVD金刚石膜进行粗加工,然后采用化学机械抛光的方法对CVD金刚石膜进行精加工.结果表明,采用游离磨料抛光时材料去除率远比固结磨料高,表面粗糙度最低达到42.2 nm.化学机械抛光方法在CVD金刚石膜的超精密抛光中表现出较大的优势,CVD金刚石膜的表面粗糙度为4.551 nm.

  3. Influence of boron doping on mechanical and tribological properties in multilayer CVD-diamond coating systems

    Indian Academy of Sciences (India)

    SAJAD HUSSAIN DIN; M A SHAH; N A SHEIKH; K A NAJAR; K RAMASUBRAMANIAN; S BALAJI; M S RAMACHANDRA RAO

    2016-12-01

    Titanium alloy (Ti6Al4V) substrates were deposited with smooth multilayer coatings, by hot filament chemical vapour deposition technique. The effect of boron doping on lattice parameter, residual stresses, hardness and coefficient of friction in multilayer-diamond coating system was studied. The frictional behaviour of the coatings was studied using a ball-on-disc micro-tribometer by sliding the coated samples of titanium alloy (Ti6Al4V) substrates against alumina (Al$_2$O$_3$) balls, and increasing normal load from 1 to 10N. The average friction coefficient decreased from 0.36 to 0.29 for undoped multilayer-diamond coating system and from 0.33 to 0.18 for borondoped (BD) multilayer-diamond coating system. The average indentation depths for undoped and BD multilayerdiamond coating systems were found to be equal to $\\sim$58 and $\\sim$65 nm, respectively, and their hardness values were 60 and 55~GPa, respectively.

  4. Behaviour of Self-Standing CVD Diamond Film with Different Dominant Crystalline Surfaces in Thermal-Iron Plate Polishing

    Institute of Scientific and Technical Information of China (English)

    CHEN Guang-Chao; ZHOU Zu-Yuan; LI Bin; ZHOU You-Liang; J. Askri; LI Cheng-Ming; TANG Wei-Zhong; TONG Yu-Mei; LU Fan-Xiu

    2006-01-01

    @@ Self-standing CVD diamond films with different dominant crystalline surfaces are polished by the thermal-iron plate polishing method. The influence of the dominant crystalline surfaces on polishing efficiency is investigated by measuring the removal rate and final roughness. The smallest rms roughness of 0.14μm is measured with smallest removal rate in the films with the initial (220) dominant crystalline surface. Activation energy for the polishing is analysed by the Arrhenius relation. It is found that the values are 170kJ/mol, 222kJ/mol and 214kJ/mol for the film with t hree different dominant crystalline surfaces. Based on these values, the polishing cause is regarded as the graphitization-controlling process. In the experiment, we find that transformation of the dominant crystalline surfaces from (111) to (220) always appears in the polishing process when we polish the (111) dominant surface.

  5. Hydrogen distribution in CVD diamond films prepared by DC arcjet operating at gas recycling mode

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Hydrogen distribution and content in diamond films deposited by DC arcjet under gas recycling mode was evaluated by nuclear reaction analysis (NRA). The films were characterized using scanning electron microscopy, X-ray diffraction and Raman spectrometry. The NRA results show that the hydrogen content in diamond films was approximately 0.6% (substrate temperature 770℃), and strongly depended on the substrate temperature. It was that the hydrogen content increased with the increase of the substrate temperature. The possibility of hydrogen trapping in the films was also discussed.

  6. 电蚀抛光CVD金刚石膜的实验研究%A Study on the Polishing of CVD Diamond Film by Electromachining Method

    Institute of Scientific and Technical Information of China (English)

    郭钟宁; 王成勇; 匡同春; 王晓初; 黄志刚

    2000-01-01

    本文提出了一种新的CVD金刚石膜抛光技术。采用该项技术,可以高效率的完成CVD金刚石膜的粗抛光。CVD金刚石膜表面被预先涂覆一层导电金属,然后采用电蚀方法对该表面进行加工,使金刚石膜突起的尖峰被迅速去除。加工中金刚石表面的石墨化使电蚀加工得以不断延续。通过单脉冲放电试验已经发现涂覆层的材料对金刚石膜的加工效果有很大影响。与普通金属加工相比,金刚石膜的电蚀过程有其完全不同的特征。通过试验和分析,本文还对金刚石膜的电蚀去除机理进行了初步探讨。%A new technique for polishing CVD diamond film has been investigated, by which rough polishing of CVD diamond film can be efficiently carried out. Diamond film is coated with a thin layer of conductive material in advance, and then EDM method is used to machine the coated surface. As a result, peaks on the surface of diamond film axe removed rapidly. During the machining, graphitization of the surface of CVD diamonds film enables EDM process to continue. The discharge experiment of single pulse shows that the material of the coated layer will evidently affect the removal volume of CVD diamond film. Compared with the machining of ordinary metal, the process of ED machining of CVD diamond film has quite different characteristics. By means of the experimental observation and the analysis of the experimental results, the removal mechanism of CVD diamond film has been discussed.

  7. Coaxial CVD diamond detector for neutron diagnostics at ShenGuang III laser facility.

    Science.gov (United States)

    Yu, Bo; Liu, Shenye; Chen, Zhongjing; Huang, Tianxuan; Jiang, Wei; Chen, Bolun; Pu, Yudong; Yan, Ji; Zhang, Xing; Song, Zifeng; Tang, Qi; Hou, Lifei; Ding, Yongkun; Zheng, Jian

    2017-06-01

    A coaxial, high performance diamond detector has been developed for neutron diagnostics of inertial confinement fusion at ShenGuangIII laser facility. A Φ10 mm × 1 mm "optical grade" chemical-vapor deposition diamond wafer is assembled in coaxial-designing housing, and the signal is linked to a SubMiniature A connector by the cathode cone. The coaxial diamond detector performs excellently for neutron measurement with the full width at half maximum of response time to be 444 ps for a 50 Ω measurement system. The average sensitivity is 0.677 μV ns/n for 14 MeV (DT fusion) neutrons at an electric field of 1000 V/mm, and the linear dynamic range is beyond three orders of magnitude. The ion temperature results fluctuate widely from the neutron time-of-flight scintillator detector results because of the short flight length. These characteristics of small size, large linear dynamic range, and insensitive to x-ray make the diamond detector suitable to measure the neutron yield, ion temperature, and neutron emission time.

  8. The adhesion of hot-filament CVD diamond films on AISI type 316 austenitic stainless steel

    NARCIS (Netherlands)

    Buijnsters, J.G.; Shankar, P.; Enckevort, W.J.P. van; Schermer, J.J.; Meulen, J.J. ter

    2004-01-01

    Steel ball indentation and scratch adhesion testing of hot filament chemical vapour deposited diamond films onto AISI type 316 austenitic stainless steel substrates using two different interlayer systems, namely chromium nitride and borided steel, have been investigated. In order to compare the adhe

  9. Filmes de diamante CVD dopado com boro. Parte I . Histórico, produção e caracterização Boron-doped CVD diamond films. Part I. History, production and characterization

    Directory of Open Access Journals (Sweden)

    Rita de Cássia Mendes de Barros

    2005-03-01

    Full Text Available This review presents a brief account concerning the production, characterization and evolution of the knowledge in the area of diamond and boron-doped diamond films. The most important methods used for the growth of these films, such as chemical vapor deposition and high pressure/high temperature systems, as well as the several kinds of reactors which can be employed are reviewed. However, larger emphasis is given to the CVD method. Morphological, structural and electric properties of these films, as well as their role in the performance of voltammetric electrodes for electrochemistry and electroanalytical chemistry are also discussed.

  10. Cutting force and wear evaluation in peripheral milling by CVD diamond dental tools

    Energy Technology Data Exchange (ETDEWEB)

    Polini, R. [Dipartimento di Scienze e Tecnologie Chimiche, Universita di Roma Tor Vergata, Via della Ricerca Scientifica, 00133 Rome (Italy)]. E-mail: polini@uniroma2.it; Allegri, A. [Dipartimento di Scienze e Tecnologie Chimiche, Universita di Roma Tor Vergata, Via della Ricerca Scientifica, 00133 Rome (Italy); Guarino, S. [Dipartimento di Ingegneria Meccanica, Universita di Roma Tor Vergata, Via del Politecnico 1, 00133 Rome (Italy); Quadrini, F. [Dipartimento di Ingegneria Meccanica, Universita di Roma Tor Vergata, Via del Politecnico 1, 00133 Rome (Italy); Sein, H. [Department of Chemistry and Materials, Manchester Metropolitan University, Chester Street, Manchester M1 5GD (United Kingdom); Ahmed, W. [Department of Chemistry and Materials, Manchester Metropolitan University, Chester Street, Manchester M1 5GD (United Kingdom)

    2004-12-22

    Co-cemented tungsten carbide (WC-Co) tools are currently employed in dental application for prosthesis fabrication. The deposition of a diamond coating onto WC-Co tools could allow both to increase the tool life and tool performance at higher speeds. However, at present it is very difficult to quantify the effective advantage of the application of a diamond coating onto dental tools compared to traditional uncoated tools. Therefore, in this work, we have deposited diamond coatings onto WC-Co dental tools having different geometries by Hot Filament Chemical Vapour Deposition (HFCVD). Prior to deposition, the WC-Co tools were pre-treated in order to roughen the surface and to modify the chemical surface composition. The use of the HFCVD process enabled the deposition of a uniform coating despite the complex geometries of the dental mills. For the first time, in accordance to the knowledge of the authors, we have studied and compared the cutting behaviour of both virgin and diamond-coated dental tools by measuring both wear and cutting force time evolution under milling a very hard Co-Cr-Mo dental alloy. To ensure constant cutting rate (20,000-r.p.m. cutting rate, 0.01-m/min feed rate and 0.5-mm depth of cut), a proper experimental apparatus was used. Three different mill geometries were considered in both coated and uncoated conditions. The results showed that, under the high-speed conditions employed, uncoated tools underwent to catastrophic failure within a few seconds of machining. Diamond-coated tools exhibited much longer tool lives. Lower forces were measured when the coated tool was employed due to the much lower material-mill friction. The best behaviour was observed for coated mills with the presence of a chip-breaker.

  11. Novel diamond cells for neutron diffraction using multi-carat CVD anvils.

    Science.gov (United States)

    Boehler, R; Molaison, J J; Haberl, B

    2017-08-01

    Traditionally, neutron diffraction at high pressure has been severely limited in pressure because low neutron flux required large sample volumes and therefore large volume presses. At the high-flux Spallation Neutron Source at the Oak Ridge National Laboratory, we have developed new, large-volume diamond anvil cells for neutron diffraction. The main features of these cells are multi-carat, single crystal chemical vapor deposition diamonds, very large diffraction apertures, and gas membranes to accommodate pressure stability, especially upon cooling. A new cell has been tested for diffraction up to 40 GPa with an unprecedented sample volume of ∼0.15 mm(3). High quality spectra were obtained in 1 h for crystalline Ni and in ∼8 h for disordered glassy carbon. These new techniques will open the way for routine megabar neutron diffraction experiments.

  12. Photoionization of monocrystalline CVD diamond irradiated with ultrashort intense laser pulse

    Science.gov (United States)

    Lagomarsino, Stefano; Sciortino, Silvio; Obreshkov, Boyan; Apostolova, Tzveta; Corsi, Chiara; Bellini, Marco; Berdermann, Eleni; Schmidt, Christian J.

    2016-02-01

    Direct laser writing of conductive paths in synthetic diamond is of interest for implementation in radiation detection and clinical dosimetry. Unraveling the microscopic processes involved in laser irradiation of diamond below and close to the graphitization threshold under the same conditions as the experimental procedure used to produce three-dimensional devices is necessary to tune the laser parameters to optimal results. To this purpose a transient currents technique has been used to measure laser-induced current signals in monocrystalline diamond detectors in a wide range of laser intensities and at different bias voltages. The current transients vs time and the overall charge collected have been compared with theoretical simulations of the carrier dynamics along the duration and after the conclusion of the 30 fs laser pulse. The generated charge has been derived from the collected charge by evaluation of the lifetime of the carriers. The plasma volume has also been evaluated by measuring the modified region. The theoretical simulation has been implemented in the framework of the empirical pseudopotential method extended to include time-dependent couplings of valence electrons to the radiation field. The simulation, in the low-intensity regime, I ˜1 TW /cm2 , predicts substantial deviation from the traditional multiphoton ionization, due to nonperturbative effects involving electrons from degenerate valence bands. For strong field with intensity of about 50 TW /cm2, nonadiabatic effects of electron-hole pair excitation become prominent with high carrier densities eventually causing the optical breakdown of diamond. The comparison of theoretical prediction with experimental data of laser-generated charge vs laser energy density yields a good quantitative agreement over six orders of magnitude. At the highest intensities the change of slope in the trend is explained taking into account the dependence of the optical parameters and the carrier mobility on plasma

  13. Optimization of Cvd Diamond Coating Type on Micro Drills in Pcb Machining

    Science.gov (United States)

    Lei, X. L.; He, Y.; Sun, F. H.

    2016-12-01

    The demand for better tools for machining printed circuit boards (PCBs) is increasing due to the extensive usage of these boards in digital electronic products. This paper is aimed at optimizing coating type on micro drills in order to extend their lifetime in PCB machining. First, the tribotests involving micro crystalline diamond (MCD), nano crystalline diamond (NCD) and bare tungsten carbide (WC-Co) against PCBs show that NCD-PCB tribopair exhibits the lowest friction coefficient (0.35) due to the unique nano structure and low surface roughness of NCD films. Thereafter, the dry machining performance of the MCD- and NCD-coated micro drills on PCBs is systematically studied, using diamond-like coating (DLC) and TiAlN-coated micro drills as comparison. The experiments show that the working lives of these micro drills can be ranked as: NCD>TiAlN>DLC>MCD>bare WC-Co. The superior cutting performance of NCD-coated micro drills in terms of the lowest flank wear growth rate, no tool degradation (e.g. chipping, tool tipping) appearance, the best hole quality as well as the lowest feed force may come from the excellent wear resistance, lower friction coefficient against PCB as well as the high adhesive strength on the underneath substrate of NCD films.

  14. Fission reactor flux monitors based on single-crystal CVD diamond films

    Energy Technology Data Exchange (ETDEWEB)

    Almaviva, S.; Marinelli, M.; Prestopino, G.; Tucciarone, A.; Verona, C.; Verona-Rinati, G. [Dipartimento di Ingegneria Meccanica, Universita di Roma ' ' Tor Vergata' ' , Via del Politecnico 1, 00133 Roma (Italy); INFN - Sezione Roma ' ' Tor Vergata' ' (Italy); Milani, E. [INFN - Sezione Roma ' ' Tor Vergata' ' (Italy); Angelone, M.; Lattanzi, D.; Pillon, M. [Associazione EURATOM-ENEA sulla Fusione, Via E. Fermi 45, 00144 Frascati (Roma) (Italy); Rosa, R. [Dipartimento Fusione e Presidio Nucleare ENEA C.R. Casaccia, Via Anguillarese 301, 00123 Roma (Italy)

    2007-09-15

    Diamond based thermal neutron flux monitors have been fabricated using single crystal diamond films, grown by chemical vapour deposition. A 3 {mu}m thick {sup 6}LiF layer was thermally evaporated on the detector surface as a converting material for thermal neutron monitoring via the {sup 6}Li(n, {alpha}) T nuclear reaction. The detectors were tested in a fission nuclear reactor. One of them was positioned 80 cm above the core mid-plane, where the neutron flux is 2.2 x 10{sup 9} neutrons/cm{sup 2}s at 1 MW resulting in a device count rate of about 150000 cps. Good stability and reproducibility of the device output were proved over the whole reactor power range (up to 1 MW). During the irradiation, several pulse height spectra were recorded, in which both products of the {sup 6}Li(n,{alpha})T reaction, e.g. 2.73 MeV tritium and the 2.06 MeV {alpha}, were clearly identified, thus excluding a degradation of the detector response. A comparison with a reference fission chamber monitor pointed out a limitation of the adopted readout electronics at high count rates, due to multiple pile-up processes. However, once this effect is properly accounted for, a good linearity of the diamond flux monitor response is observed as a function of the fission chamber one, as well as an excellent agreement between the temporal behaviour of the two detector response. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Optical and structural properties of polycrystalline CVD diamond films grown on fused silica optical fibres pre-treated by high-power sonication seeding

    Science.gov (United States)

    Bogdanowicz, R.; Śmietana, M.; Gnyba, M.; Gołunski, Ł.; Ryl, J.; Gardas, M.

    2014-09-01

    In this paper, the growth of polycrystalline chemical vapour deposition (CVD) diamond thin films on fused silica optical fibres has been investigated. The research results show that the effective substrate seeding process can lower defect nucleation, and it simultaneously increases surface encapsulation. However, the growth process on glass requires high seeding density. The effects of suspension type and ultrasonic power were the specific objects of investigation. In order to increase the diamond density, glass substrates were seeded using a high-power sonication process. The highest applied power of sonotrode reached 72 W during the performed experiments. The two, most common diamond seeding suspensions were used, i.e. detonation nanodiamond dispersed in (a) dimethyl sulfoxide and (b) deionised water. The CVD diamond nucleation and growth processes were performed using microwave plasma assisted chemical vapour deposition system. Next, the seeding efficiency was determined and compared using the numerical analysis of scanning electron microscopy images. The molecular composition of nucleated diamond was examined with micro-Raman spectroscopy. The sp3/sp2 band ratio was calculated using Raman spectra deconvolution method. Thickness, roughness, and optical properties of the nanodiamond films in UV-vis wavelength range were investigated by means of spectroscopic ellipsometry. It has been demonstrated that the high-power sonication process can improve the seeding efficiency on glass substrates. However, it can also cause significant erosion defects at the fibre surface. We believe that the proposed growth method can be effectively applied to manufacture the novel optical fibre sensors. Due to high chemical and mechanical resistance of CVD diamond films, deposition of such films on the sensors is highly desirable. This method enables omitting the deposition of an additional adhesion interlayer at the glass-nanocrystalline interface, and thus potentially increases

  16. Characterizations of microwave plasma CVD grown polycrystalline diamond coatings for advanced technological applications

    Directory of Open Access Journals (Sweden)

    Awadesh Kumar Mallik

    2014-06-01

    Full Text Available Polycrystalline diamond (PCD coatings ranging from few microns to several hundred microns thickness have been grown by 915 MHz microwave plasma reactor with 9000 W power. The coatings were deposited on 100 mm diameter silicon (Si substrate from few hours to several days of continuous runs. PCD coatings were made freestanding by wet chemical etching technique. The deposited PCDs were evaluated by X-ray diffraction (XRD, scanning electron microscopy (SEM, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS for physical characterization and compared with authors’ earlier work. Refractive index of 2.41 was obtained at 633 nm wavelength and a maximum of 6.6 W·cm-1K-1 value for thermal conductivity could be achieved with the grown coatings. The values are well above the existing non-diamond heat spreading substrates, which makes the grown PCDs as candidates for heat spreaders in different technological applications. High refractive index along with translucent nature of the white freestanding PCDs, make them potential candidate for optical windows.

  17. Diamond like carbon coatings deposited by microwave plasma CVD: XPS and ellipsometric studies

    Indian Academy of Sciences (India)

    R M Dey; M Pandey; D Bhattacharyya; D S Patil; S K Kulkarni

    2007-12-01

    Diamond-like carbon (DLC) films were deposited by microwave assisted chemical vapour deposition system using d.c. bias voltage ranging from –100 V to –300 V. These films were characterized by X-ray photoelectron spectroscopy (XPS) and spectroscopic ellipsometry techniques for estimating 3/2 ratio. The 3/2 ratio obtained by XPS is found to have an opposite trend to that obtained by spectroscopic ellipsometry. These results are explained using sub-plantation picture of DLC growth. Our results clearly indicate that the film is composed of two different layers, having entirely different properties in terms of void percentage and 3/2 ratio. The upper layer is relatively thinner as compared to the bottom layer.

  18. Belle-II VXD radiation monitoring and beam abort with sCVD diamond sensors

    Science.gov (United States)

    Adamczyk, K.; Aihara, H.; Angelini, C.; Aziz, T.; Babu, V.; Bacher, S.; Bahinipati, S.; Barberio, E.; Baroncelli, T.; Basith, A. K.; Batignani, G.; Bauer, A.; Behera, P. K.; Bergauer, T.; Bettarini, S.; Bhuyan, B.; Bilka, T.; Bosi, F.; Bosisio, L.; Bozek, A.; Buchsteiner, F.; Casarosa, G.; Ceccanti, M.; Červenkov, D.; Chendvankar, S. R.; Dash, N.; Divekar, S. T.; Doležal, Z.; Dutta, D.; Forti, F.; Friedl, M.; Hara, K.; Higuchi, T.; Horiguchi, T.; Irmler, C.; Ishikawa, A.; Jeon, H. B.; Joo, C.; Kandra, J.; Kang, K. H.; Kato, E.; Kawasaki, T.; Kodyš, P.; Kohriki, T.; Koike, S.; Kolwalkar, M. M.; Kvasnička, P.; Lanceri, L.; Lettenbicher, J.; Mammini, P.; Mayekar, S. N.; Mohanty, G. B.; Mohanty, S.; Morii, T.; Nakamura, K. R.; Natkaniec, Z.; Negishi, K.; Nisar, N. K.; Onuki, Y.; Ostrowicz, W.; Paladino, A.; Paoloni, E.; Park, H.; Pilo, F.; Profeti, A.; Rashevskaya, I.; Rao, K. K.; Rizzo, G.; Rozanska, M.; Sandilya, S.; Sasaki, J.; Sato, N.; Schultschik, S.; Schwanda, C.; Seino, Y.; Shimizu, N.; Stypula, J.; Tanaka, S.; Tanida, K.; Taylor, G. N.; Thalmeier, R.; Thomas, R.; Tsuboyama, T.; Uozumi, S.; Urquijo, P.; Vitale, Lorenzo; Volpi, M.; Watanuki, S.; Watson, I. J.; Webb, J.; Wiechczynski, J.; Williams, S.; Würkner, B.; Yamamoto, H.; Yin, H.; Yoshinobu, T.

    2016-07-01

    The Belle-II VerteX Detector (VXD) has been designed to improve the performances with respect to Belle and to cope with an unprecedented luminosity of 8 ×1035cm-2s-1 achievable by the SuperKEKB. Special care is needed to monitor both the radiation dose accumulated throughout the life of the experiment and the instantaneous radiation rate, in order to be able to promptly react to sudden spikes for the purpose of protecting the detectors. A radiation monitoring and beam abort system based on single-crystal diamond sensors is now under an active development for the VXD. The sensors will be placed in several key positions in the vicinity of the interaction region. The severe space limitations require a challenging remote readout of the sensors.

  19. N-Type Conductive Ultrananocrystalline Diamond Films Grown by Hot Filament CVD

    Directory of Open Access Journals (Sweden)

    Michael Mertens

    2015-01-01

    Full Text Available We present the synthesis of ultrananocrystalline diamond (UNCD films by application of hot filament chemical vapor deposition (HFCVD. We furthermore studied the different morphological, structural, and electrical properties. The grown films are fine grained with grain sizes between 4 and 7 nm. The UNCD films exhibit different electrical conductivities, dependent on grain boundary structure. We present different contact metallizations exhibiting ohmic contact behavior and good adhesion to the UNCD surface. The temperature dependence of the electrical conductivity is presented between −200 and 900°C. We furthermore present spectroscopic investigations of the films, supporting that the origin of the conductivity is the structure and volume of the grain boundary.

  20. Investigation of charge multiplication in single crystalline CVD diamond particle detectors

    Science.gov (United States)

    Muškinja, M.; Cindro, V.; Gorišek, A.; Kagan, H.; Kramberger, G.; Mandić, I.; Mikuž, M.; Phan, S.; Smith, D. S.; Zavrtanik, M.

    2017-01-01

    A special metallization pattern was created on a single crystalline diamond detector aimed at creating high enough electric field for impact ionization in the detector material. Electric field line focusing through electrode design and very high bias voltages were used to obtain high electric fields. Previous measurements and theoretical calculations indicated that drifting charge multiplication by impact ionization could take place. A large increase of induced charge was observed for the smallest dot electrode which points to charge multiplication while for the large dot and pad detector structure no such effect was observed. The evolution of induced currents was also monitored with the transient current technique. Induced current pulses with duration of order 1 μs were measured. The multiplication gain was found to depend on the particle rate.

  1. Enhancement in Tribological and Mechanical Properties of Cemented Tungsten Carbide Substrates using CVD-diamond Coatings

    Directory of Open Access Journals (Sweden)

    K.A. Najar

    2017-03-01

    Full Text Available An experimental investigation has been carried out to study the influence on the performance characteristics of a cutting tool material notably known as cemented tungsten carbide (WC-Co. A comparison has been documented between nanocrystalline diamond (NCD and microcrystalline diamond (MCD coatings deposited on two cemented tungsten carbide (WC-Co substrates with the architectures of WC-Co/NCD and WC-Co/MCD, using hot filament chemical vapor deposition (HFCVD technique. In the present work, the friction characteristics were studied using ball-on-disc type linear reciprocating micro-tribometer, under the application of 1–10 N normal loads, when sliding against smooth alumina (Al2O3 ceramic ball for the total duration of 20 min, under dry sliding condition. Nanoindentation tests were also conducted using Berkovich nanoindenter for the purpose of measurement of hardness and elastic modulus values. However, the average value of friction coefficient (COF corresponding to MCD and NCD coatings decrease from ~0.37–0.32 and ~0.30–0.27, respectively when the load is increased from 1–10 N. However, for conventional WC-Co substrate the average COF increases from ~0.60–0.75, under the same input operating conditions. The wear tracks formed on the surfaces of NCD, MCD and WC-Co, after sliding were characterised using Raman spectroscopy and scanning electron microscopy (SEM techniques. Therefore, the results will serve breakthrough information for the designer to design the cutting tool or mechanical component using this novel coating procedure.

  2. Absolute x-ray and neutron calibration of CVD-diamond-based time-of-flight detectors for the National Ignition Facility

    Science.gov (United States)

    Rosenthal, A.; Kabadi, N. V.; Sio, H.; Rinderknecht, H.; Gatu Johnson, M.; Frenje, J. A.; Seguin, F. H.; Petrasso, R. D.; Glebov, V.; Forrest, C.; Knauer, J.

    2016-10-01

    The particle-time-of-flight (pTOF) detector at the National Ignition Facility routinely measures proton and neutron nuclear bang-times in inertial confinement fusion (ICF) implosions. The active detector medium in pTOF is a chemical vapor deposition (CVD) diamond biased to 250 - 1500 V. This work discusses an absolute measurement of CVD diamond sensitivity to continuous neutrons and x-rays. Although the impulse response of the detector is regularly measured on a diagnostic timing shot, absolute sensitivity of the detector's response to neutrons and x-rays has not been fully established. X-ray, DD-n, and DT-n sources at the MIT HEDP Accelerator Facility provide continuous sources for testing. CVD diamond detectors are also fielded on OMEGA experiments to measure sensitivity to impulse DT-n. Implications for absolute neutron yield measurements at the NIF using pTOF detectors will be discussed. This work was supported in part by the U.S. DoE and LLNL.

  3. Electrochemical Properties of Boron-Doped Diamond Electrodes Prepared by Hot Cathode Direct Current Plasma CVD

    Directory of Open Access Journals (Sweden)

    Hong Yan PENG

    2016-05-01

    Full Text Available A series of boron-doped diamond (BDD films were deposited by using a hot cathode direct current plasma chemical vapor deposition(HCDC-PCVD system with different ratios of CH4/H2/B(OCH33 (trimethylborate gas mixture. The morphology, structure and quality of BDD films were controled by SEM, XRD and Raman measurements. The electrochemical properties of the BDD films were investigated by electrochemical methods. Cyclic voltammetric performances of the BDD films indicated that the main determinant in the electrochemical characteristics of BDD films was the boron doping amount. The threshold potential for oxygen evolution increased from 1 V to 2.5 V. Meanwhile, the electrochemical potential window of BDD films was enlarged from 2.2 V to 4.5 V when the B content was increased from 1.75 × 1019cm-3 to 2.4 × 1021 cm−3. The cyclic voltammograms of BDD films in K4Fe(CN6 and K3Fe(CN6 mixed solution indicated that the behavior of Fe(CN6-3/-4 redox couple could be regarded as semi-reversible.DOI: http://dx.doi.org/10.5755/j01.ms.22.2.12926

  4. Effect of CVD-Diamond on the Tribological and Mechanical Performance of Titanium Alloy (Ti6Al4V

    Directory of Open Access Journals (Sweden)

    S.H. Din

    2016-12-01

    Full Text Available Nano-crystalline diamond and microcrystalline diamond films have been separately deposited on chemically treated titanium alloy (Ti6Al4V substrates from methane/hydrogen (CH4/H2 gas mixture, using hot filament chemical vapor deposition technique. The coatings have architecture of Ti6Al4V/NCD and Ti6Al4V/MCD. The as grown nano-crystalline diamond and microcrystalline diamond films were characterized using high resolution scanning electron microscope and Raman’s spectroscopy. The residual stresses along the surface of nano-crystalline diamond coatings and micro-crystalline diamond coatings are compressive in nature as shown by the Raman spectroscopy. Nanoindentation tests were also conducted using Berkovich nanoindenter for the purpose of measurement of hardness and elastic modulus values. The indentation depth for microcrystalline diamond coating was 65 nm, whereas for nanocrystalline diamond coating, it was 72 nm. Microcrystalline diamond and nanocrystalline diamond coatings have yielded the super-hardness of ~55 G Pa and ~38 G Pa respectively. The average coefficient of friction of microcrystalline diamond and nanocrystalline diamond coatings decrease from 0.305-0.27 to 0.068-0.053, respectively, when the load is increased from 1 N to 10 N. However, for conventional Ti6Al4V substrate the average coefficient of friction changes from 0.625 to 0.38 under the same input conditions.

  5. Influence of growth conditions on microstructure and defects in diamond coatings grown by microwave plasma enhanced CVD

    Indian Academy of Sciences (India)

    Kalyan Sundar Pal; Sandip Bysakh; Awadesh Kumar Mallik; Nandadulal Dandapat; Someswar Datta; Bichitra K Guha

    2015-06-01

    Diamond coatings were grown on SiO2/Si substrate under various process conditions by microwave plasma chemical vapour deposition (MPCVD) using CH4/H2 gas mixture. In this paper, we present a microstructural study to elucidate on the growth mechanism and evolution of defects, viz., strain, dislocations, stacking faults, twins and non-diamond impurities in diamond coatings grown under different process conditions. Transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy were used to characterize the diamond coatings. It has been shown that our new approach of prolonged substrate pre-treatment under hydrogen plasma yielded a new growth sequence that the SiO2 layer on the Si substrate was first reduced to yield Si layer of ∼150 nm thickness before diamond was allowed to grow under CH4–H2 plasma, created subsequently. It has also been shown that Si and O as impurity from the substrate hinders the initial diamond growth to yield non-diamond phases. It is being suggested that the crystal defects like twins, stacking faults, dislocations in the diamond grains and dislocations in the intermediate Si layer are generated due to the development of non-uniform stresses during diamond growth at high temperature.

  6. Resonant excitation of ethylene molecules in the combustion flame CVD of diamond using a wavelength tunable CO2 laser

    Science.gov (United States)

    Xie, Z. Q.; Park, J. B.; He, X. N.; Gao, Y.; Zhou, Y. S.; Lu, Y. F.

    2010-02-01

    CO2 laser resonant excitations of precursor molecules were applied in combustion flame synthesis of diamond films. The combustion flame was produced from a mixture of ethylene (C2H4), acetylene (C2H2) and oxygen (O2). A wavelength-tunable CO2 laser with wavelength range from 9.2 to 10.9 μm was used for wavelength-matched excitation of the ethylene molecules. By irradiating the flame using CO2 laser at 10.532 μm, the ethylene molecules were resonantly excited through the CH2 wagging vibrational mode (ν7, 949.3 cm-1). Irradiation of the flame using the common CO2 laser wavelength at 10.591 μm was also carried out for comparison. It was found that diamond synthesis was more obviously enhanced by the CO2 laser resonant excitation at 10.532 μm as compared to that at 10.591 μm. Firstly, the flame was shortened by 50%, indicating a promoted reaction in the process. Secondly, the diamond grain sizes as well as the diamond film thicknesses were increased by 200~300% and 160% respectively, indicating a higher growth rate of diamond films. Finally, Raman spectra of the diamond sample showed a sharp diamond peak at 1334 cm-1 and a suppressed G-band, indicating higher diamond quality.

  7. CVD金刚石薄膜在钨丝和碳纤维上的制备%Preparation of CVD diamond coatings on W wire and C fiber

    Institute of Scientific and Technical Information of China (English)

    何贤昶; 沈荷生; 张志明; 胡晓君; 杨小倩; 万永中

    2001-01-01

    用CVD方法在钨丝和碳纤维上沉积金刚石薄膜。约含有10000根纤维的纤维束经特殊 处理后分离为单根。生长条件使碳纤维中心在CVD生长结束后仍保持固态。CVD金刚石在纤 维上生长的平均激活能为93.15kJ/mol。SEM照片给出了纤维涂层在不同生长条件下的表面和 中心的形貌。纤维内部的石墨碳和外部的金刚石层有很大的不同。钨丝的断裂强度和杨氏模量 的测量表明,具有金刚石涂层的钨丝的断裂强度为0.567GPa,非常接近不具有金刚石涂层的钨 丝的断裂强度。但具有金刚石涂层的钨丝的断裂应变为4.8%,比没有金刚石涂层的钨丝的断 裂应变7%要小得多。这表明了金刚石涂层可以减少钨丝的断裂应力,提高其机械性能。%Diamond growth on W-wire and C-fiber substrates was studied. A treatment was used to separate fibers one by one from a bunch of more than 10000 fibers. The selected growth condition was to keep the carbon fiber core solid after CVD growth. Activation energy of CVD coated fibers is 93.15 kJ/mol in average. SEM pictures show surface and core morphology of the coatings under different treatment conditions. There are two different contrasts related to interior graphite carbon and exterior diamond layer. Wire fracture strength and Young's modulus measurement indicates that the fracture strength of W wire with diamond coating is 0.567 GPa, very close to its value without coating. However, the fracture strain of the wire with diamond coating is 4.8% , which is much less than that of W wire fracture strain of 7% . It means that diamond coated wire may reduce wire fracture strain and improve its mechanical property.

  8. Atomic-Level Investigation of CHx and C2Hx Adsorption on β-SiC (111 Surface for CVD Diamond Growth from DFT Calculations

    Directory of Open Access Journals (Sweden)

    Naichao Chen

    2011-01-01

    Full Text Available The focus of this paper is on the adsorption of unsaturated hydrocarbon molecules on β-SiC (111 surfaces during diamond film growth. The CHx and C2Hx molecules have been investigated to obtain a specific insight into absorbing diamond processes on the atomic scale. Structural and electronic properties of CHx and C2Hx adsorption on the Si- and C-terminated surfaces have been studied by first-principles calculations based on density functional theory (DFT. From the calculated energetics and geometries, we find that C2Hx adsorption on the Si-terminated surfaces has six possible surface reconstructions. For the C-terminated surface, there exist eight possible surface reconstructions. Five surface reconstructions, including CH2 adsorption on the Si- and C-terminated surface, CH–CH2 and CH=CH2 adsorption on the C-terminated surface, and C2H5 adsorption on the Si-terminated surface, have the largest hydrogen adsorption energies and more stability of surface reconstructions. Calculations demonstrate that the Si-terminated surface is energetically more favorable for fabricating CVD diamond coatings than the C-terminated surface.

  9. CVD金刚石涂层拉丝模温度场数值分析%Numerical Analysis of CVD Diamond Wire Drawing Temperature Field

    Institute of Scientific and Technical Information of China (English)

    黄美健; 左敦稳; 卢文壮; 徐锋; 张旭辉

    2012-01-01

    Substrate temperature is one of the key parameters in diamond hot filament chemical vapor deposition (HFCVD). Uniform substrate temperature field is even more important in diamond deposition on the interior surface of wire drawing. This paper carries out numerical analysis of the temperature field of wire drawing in HFCVD system and obtains the temperature distribution and the influence characteristics of the hot filament parameters on the magnitude and uniformity of substrate temperature field, which provide a guide for the fabrication of the CVD diamond wire drawing.%衬底温度是热丝化学气相沉积(HFCVD)制备金刚石薄膜的重要参数之一,在拉丝模表面沉积CVD金刚石涂层时,均匀的衬底温度场显得尤为重要.对HFCVD系统中制备CVD金刚石涂层时拉丝模衬底温度场进行数值分析,得到了拉丝模温度场的分布和热丝参数对衬底温度场的影响规律,为CVD金刚石涂层拉丝模的制备提供重要指导.

  10. Tl and OSL dosimetry of diamond films CVD pure and unpurified with boron-carbon; Dosimetria Tl y OSL de peliculas de diamante CVD puras e impurificadas con boro-carbono

    Energy Technology Data Exchange (ETDEWEB)

    Melendrez, R.; Pedroza M, M.; Chernov, V.; Ochoa N, J.D.; Bernal, R.; Barboza F, M. [CIF, UNISON, A.P. 5-088, 83190 Hermosillo, Sonora (Mexico); Castaneda, B. [Departamento de Fisica, Universidad de Sonora, Apdo. Postal 1626, Hermosillo, Sonora (Mexico); Goncalves, J.A.N.; Sandonato, G.M. [Laboratorio Associado de Plasma, Instituto Nacional de Pesquisas Espaciais C.P. 515- 12201 -970, Sao Jose dos Campos, SP (Brazil); Cruz Z, E. [Instituto de Ciencias Nucleares, UNAM, Apdo. Postal 70-543, 04510 Mexico D.F. (Mexico); Preciado F, S.; Cruz V, C.; Brown, F. [Departamento de Investigacion en Polimeros y Materiales de la Universidad de Sonora, Apdo. Postal 130, 83000 Hermosillo, Sonora (Mexico); Schreck, M. [Universitaet Augsburg, Institut fuer Physik D-86135 Augsburg (Germany)

    2004-07-01

    The diamond is a material that possesses extreme physical properties, such as its hardness to the radiation, its low chemical reactivity besides its equivalence to the human tissue, which qualify him as an ideal material for radiation dosimetry. In this work, it was studied the thermal and optically stimulated response (Tl and OSL) of polycrystalline diamond films grown by the technique of CVD pure and contaminated with Boron-carbon (B/C) with the intention of characterizing their efficiency like a dosemeter for radiation in a range of 0 - 3000 Gy. For the case of the films without impurities, the Tl curve presents four main peaks, two of them in an interval of temperatures of 150-200 C and other two additional around of 250-400 C. The dependence of the response of integrated Tl and that of OSL always maintained a lineal relationship with the exhibition dose up to 100 Gy. The behavior of the films contaminated with B/C (2000 - 20000 ppm) was established through experiments that involved the signal of OSL and their relationship with the Tl response. It was found that this processes are correlated, since the electrons caught in the traps of low temperature (50 - 250 C) of the Tl they are the electrons that recombining with more probability to provide the signal of OSL. According to these results it is possible to propose the diamond films as a good candidate for dosimetry to, using the traditional technique of Tl so much as well as the but recent of OSL. (Author)

  11. Comprehensive Evaluation of the Properties of Nanocrystalline Diamond Coatings Grown Using CVD with E/H Field Glow Discharge Stabilization

    Directory of Open Access Journals (Sweden)

    Iu. Nasieka

    2015-01-01

    Full Text Available The nanocrystalline diamond films (coatings were prepared using the plasma enhanced chemical vapor deposition (PECVD technique. In this method, direct current (DC glow discharge in the crossed E/H fields was used to activate the gas phase. The diamond coatings were deposited from the working gas mixture CH4/H2 with addition of nitrogen in various concentrations. It was ascertained that addition of N2 to the working gas mixture leads to reduction in the sizes of diamond grains as well as to the substantial decrease in the resistivity of the studied films. The electrophysical data are in good agreement with the changes induced by varying the N2 content in the Raman scattering spectra. The increase in the N2 concentration causes significant lowering of the crystalline diamond related peak and increase in the intensity of the peaks related to the sp2-bonded carbon. These changes in the spectra indicate significant disordering of the structure of prepared films and its uniformity in the nanodiamond film volume. With the great possibility, it is associated with a decrease in the sizes of diamond crystalline grains and tendency of NCD film to amorphization.

  12. Diagnosis of gas phase near the substrate surface in diamond film deposition by high-power DC arc plasma jet CVD

    Institute of Scientific and Technical Information of China (English)

    Zuyuan Zhou; Guangchao Chen; Bin Li; Weizhong Tang; Fanxiu Lv

    2007-01-01

    Optical emission spectroscopy (OES) was used to study the gas phase composition near the substrate surface during diamond deposition by high-power DC arc plasma jet chemical vapor deposition (CVD). C2 radical was determined as the main carbon radical in this plasma atmosphere. The deposition parameters, such as substrate temperature, anode-substrate distance, methane concentration, and gas flow rate, were inspected to find out the influence on the gas phase. A strong dependence of the concentrations and distribution of radicals on substrate temperature was confirmed by the design of experiments (DOE). An explanation for this dependence could be that radicals near the substrate surface may have additional ionization or dissociation and also have recombination,or are consumed on the substrate surface where chemical reactions occur.

  13. Industrial diamond

    Science.gov (United States)

    Olson, D.W.

    2013-01-01

    Estimated 2012 world production of natural and synthetic industrial diamond was about 4.45 billion carats. During 2012, natural industrial diamonds were produced in at least 20 countries, and synthetic industrial diamond was produced in at least 12 countries. About 99 percent of the combined natural and synthetic global output was produced in Belarus, China, Ireland, Japan, Russia, South Africa and the United States. During 2012, China was the world’s leading producer of synthetic industrial diamond followed by the United States and Russia. In 2012, the two U.S. synthetic producers, one in Pennsylvania and the other in Ohio, had an estimated output of 103 million carats, valued at about $70.6 million. This was an estimated 43.7 million carats of synthetic diamond bort, grit, and dust and powder with a value of $14.5 million combined with an estimated 59.7 million carats of synthetic diamond stone with a value of $56.1 million. Also in 2012, nine U.S. firms manufactured polycrystalline diamond (PCD) from synthetic diamond grit and powder. The United States government does not collect or maintain data for either domestic PCD producers or domestic chemical vapor deposition (CVD) diamond producers for quantity or value of annual production. Current trade and consumption quantity data are not available for PCD or for CVD diamond. For these reasons, PCD and CVD diamond are not included in the industrial diamond quantitative data reported here.

  14. Highly segmented CVD diamond detectors and high-resolution momentum measurements in knockout reactions; Hochsegmentierte CVD Diamant Detektoren und hochaufloesende Impulsmessungen in Knockout Reaktionen

    Energy Technology Data Exchange (ETDEWEB)

    Schwertel, Sabine

    2009-11-26

    highly segmented detectors with an efficiency {epsilon}>98 % could be built from this material. The diamond detectors were segmented in our laboratory and achieved a time resolution of {sigma}{sub t}=75 ps. Medium-size (25.4 x 25.4 mm{sup 2}) micro-strip detectors were tested at the FRS and at the ALADIN/LAND setup at GSI. The obtained position resolution was in the range of the strip size of 200 {mu}m. First full-size detectors (50 x 50 mm{sup 2}) will be completed soon. (orig.)

  15. Influence of melt treatments and polished CVD diamond coated insert on cutting force and surface integrity in turning of Al–7Si and Al–7Si–2.5Cu cast alloys

    Indian Academy of Sciences (India)

    K G Basavakumar; P G Mukunda; M Chakraborty

    2007-10-01

    The microstructures, machinability and surface characteristics of Al–7Si and Al–7Si–2.5Cu cast alloys were studied after various melt treatments like grain refinement and modification. The results indicate that combined grain refined and modified Al–7Si–2.5Cu cast alloys have microstructures consisting of uniformly distributed -Al grains, eutectic Al-silicon and fine CuAl2 particles in the interdendritic region. These alloys exhibited better machinability and surface characteristics in the cast condition compared with the same alloy subjected to only grain refinement or modification. Performances of the turning inserts (uncoated and polished CVD diamond coated) were evaluated in machining Al–7Si and Al–7Si–2.5Cu cast alloys under dry environment using a lathe. The polished CVD diamond coated insert outperformed the uncoated cutting insert which suffered from sizeable edge buildup leading to higher cutting force and poor surface finish. The polished CVD diamond coated insert shows a very small steady wear without flaking of the diamond film during cutting. This paper attempts to investigate the influence of grain refinement, modification and combined action of both on the microstructural changes in the Al–7Si and Al–7Si–2.5Cu cast alloys and their machinability and surface finish when different turning inserts are used.

  16. Cryotribology of diamond and graphite

    Energy Technology Data Exchange (ETDEWEB)

    Iwasa, Yukikazu; Ashaboglu, A.F.; Rabinowicz, E.R. [Francis Bitter Magnet Lab., Cambridge, MA (United States)

    1996-12-31

    An experimental study was carried out on the tribological behavior of materials of interest in cryogenic applications, focusing on diamond and graphite. Both natural diamond (referred in the text as diamond) and chemical-vapor-deposition (CVD) diamond (CVD-diamond) were used. The experiment was carried out using a pin-on-disk tribometer capable of operating at cryogenic temperatures, from 4.2 to 293 K. Two basic scenarios of testing were used: (1) frictional coefficient ({mu}) vs velocity (v) characteristics at constant temperatures; (2) {mu} vs temperature (T) behavior at fixed sliding speeds. For diamond/CVD-diamond, graphite/CVD-diamond, stainless steel/CVD-diamond pairs, {mu}`s are virtually velocity independent. For each of diamond/graphite, alumina/graphite, and graphite/graphite pairs, the {partial_derivative}{mu}/{partial_derivative}v characteristic is favorable, i.e., positive. For diamond/CVD-diamond and graphite/CVD-diamond pairs, {mu}`s are nearly temperature independent between in the range 77 - 293 K. Each {mu} vs T plot for pin materials sliding on graphite disks has a peak at a temperature in the range 100 - 200 K.

  17. Optically stimulated luminescence and thermoluminescence in CVD diamond and dosimetric evaluation in fields of ionizing radiation; Luminiscencia opticamente estimulada y termoluminiscencia en diamante DQV y evaluacion dosimetrica en campos de radiacion ionizante

    Energy Technology Data Exchange (ETDEWEB)

    Barboza F, M.; Chernov, V.; Pedroza M, M. [Centro de Investigaciones en Fisica, Universidad de Sonora, A.P. 5-088, 83190 Hermosillo, Sonora (Mexico); Schreck, M. [Universitat Augsburg, Institut fur Physik D-86135, Augsburg (Germany); Preciado F, S.; Melendrez, R. [Universidad de Sonora, A.P. 130, 83000 Hermosillo, Sonora (Mexico)

    2006-07-01

    The optically stimulated luminescence (OSL) results a highly appropriate dosimetric technique for readings of absorbed radiation 'in alive' and 'in situ', as well as in real time. The CVD diamond on the other hand presents excellent qualities like radiation reader thanks to its reproducibility, radiation resistance, biocompatibility and non toxicity. The present work studies the answer of two diamond films pure and polluted with nitrogen (750 ppm) grown by the Chemical Vapor Deposition method (CVD) on silicon substrate (001) irradiated with beta (Sr-90) in the 0.833-100 Gy interval. The optical stimulation was carried out by 40 seconds with infrared laser (830 nm, 0.36 W/cm{sup 2}) and the filter BG-39 (300-600 nm) coupled the PM. The intensity and the decay of the hyperbolic type of the LOE curves were similar in both samples, for the non doped diamond were observed trapping states in 200-380 C being compared with those that it presents the polluted diamond with nitrogen in 80-277 C. The dosimetric behavior in the pure sample is observed lineal in two regions 0-16 Gy and in 30-100 Gy, only the doped sample didn't present linearity in the all range of the studied dose. The advantage is stood out of LOE on TL because the first one not requires of thermal stimulation in such a way that is more appropriate to detect and to measure radiation doses in biomedicine. (Author)

  18. Ion beam induced charge characterisation of a silicon microdosimeter using a heavy ion microprobe

    Science.gov (United States)

    Cornelius, Iwan; Siegele, Rainer; Rosenfeld, Anatoly B.; Cohen, David D.

    2002-05-01

    An ion beam induced charge (IBIC) facility has been added to the existing capabilities of the ANSTO heavy ion microprobe and the results of the first measurements are presented. Silicon on insulator (SOI) diode arrays with microscopic junction sizes have recently been proposed as microdosimeters for hadron therapy. A 20 MeV carbon beam was used to perform IBIC imaging of a 10 μm thick SOI device.

  19. Ultratough single crystal boron-doped diamond

    Science.gov (United States)

    Hemley, Russell J [Carnegie Inst. for Science, Washington, DC ; Mao, Ho-Kwang [Carnegie Inst. for Science, Washington, DC ; Yan, Chih-Shiue [Carnegie Inst. for Science, Washington, DC ; Liang, Qi [Carnegie Inst. for Science, Washington, DC

    2015-05-05

    The invention relates to a single crystal boron doped CVD diamond that has a toughness of at least about 22 MPa m.sup.1/2. The invention further relates to a method of manufacturing single crystal boron doped CVD diamond. The growth rate of the diamond can be from about 20-100 .mu.m/h.

  20. Diamond heteroepitaxial lateral overgrowth

    Science.gov (United States)

    Tang, Yung-Hsiu

    This dissertation describes improvements in the growth of single crystal diamond by microwave plasma-assisted chemical vapor deposition (CVD). Heteroepitaxial (001) diamond was grown on 1 cm. 2 a-plane sapphiresubstrates using an epitaxial (001) Ir thin-film as a buffer layer. Low-energy ion bombardment of the Ir layer, a process known as bias-enhanced nucleation, is a key step in achieving a high density of diamond nuclei. Bias conditions were optimized to form uniformly-high nucleation densities across the substrates, which led to well-coalesced diamond thin films after short growth times. Epitaxial lateral overgrowth (ELO) was used as a means of decreasing diamond internal stress by impeding the propagation of threading dislocations into the growing material. Its use in diamond growth requires adaptation to the aggressive chemical and thermal environment of the hydrogen plasma in a CVD reactor. Three ELO variants were developed. The most successful utilized a gold (Au) mask prepared by vacuum evaporation onto the surface of a thin heteroepitaxial diamond layer. The Au mask pattern, a series of parallel stripes on the micrometer scale, was produced by standard lift-off photolithography. When diamond overgrows the mask, dislocations are largely confined to the substrate. Differing degrees of confinement were studied by varying the stripe geometry and orientation. Significant improvement in diamond quality was found in the overgrown regions, as evidenced by reduction of the Raman scattering linewidth. The Au layer was found to remain intact during diamond overgrowth and did not chemically bond with the diamond surface. Besides impeding the propagation of threading dislocations, it was discovered that the thermally-induced stress in the CVD diamond was significantly reduced as a result of the ductile Au layer. Cracking and delamination of the diamond from the substrate was mostly eliminated. When diamond was grown to thicknesses above 0.1 mm it was found that

  1. Electrochemically assisted deposition of hydroxyapatite on Ti6Al4V substrates covered by CVD diamond films — Coating characterization and first cell biological results

    Energy Technology Data Exchange (ETDEWEB)

    Strąkowska, Paulina [Gdańsk University of Technology, Mechanical Engineering Faculty (Poland); Gdańsk University of Technology, Faculty of Electronics, Telecommunications, and Informatics (Poland); Beutner, René [Max Bergmann Center, Technische Universität Dresden (Germany); Gnyba, Marcin [Gdańsk University of Technology, Faculty of Electronics, Telecommunications, and Informatics (Poland); Zielinski, Andrzej [Gdańsk University of Technology, Mechanical Engineering Faculty (Poland); Scharnweber, Dieter, E-mail: Dieter.Scharnweber@tu-dresden.de [Max Bergmann Center, Technische Universität Dresden (Germany)

    2016-02-01

    Although titanium and its alloys are widely used as implant material for orthopedic and dental applications they show only limited corrosion stability and osseointegration in different cases. The aim of the presented research was to develop and characterize a novel surface modification system from a thin diamond base layer and a hydroxyapatite (HAp) top coating deposited on the alloy Ti6Al4V widely used for implants in contact with bone. This coating system is expected to improve both the long-term corrosion behavior and the biocompatibility and bioactivity of respective surfaces. The diamond base films were obtained by Microwave Plasma Assisted Chemical Vapor Deposition (MW-PACVD); the HAp coatings were formed in aqueous solutions by electrochemically assisted deposition (ECAD) at varying polarization parameters. Scanning electron microscopy (SEM), Raman microscopy, and electrical conductivity measurements were applied to characterize the generated surface states; the calcium phosphate coatings were additionally chemically analyzed for their composition. The biological properties of the coating system were assessed using hMSC cells analyzing for cell adhesion, proliferation, and osteogenic differentiation. Varying MW-PACVD process conditions resulted in composite coatings containing microcrystalline diamond (MCD/Ti-C), nanocrystalline diamond (NCD), and boron-doped nanocrystalline diamond (B-NCD) with the NCD coatings being dense and homogeneous and the B-NCD coatings showing increased electrical conductivity. The ECAD process resulted in calcium phosphate coatings from stoichiometric and non-stoichiometric HAp. The deposition of HAp on the B-NCD films run at lower cathodic potentials and resulted both in the highest coating mass and the most homogenous appearance. Initial cell biological investigations showed an improved cell adhesion in the order B-NCD > HAp/B-NCD > uncoated substrate. Cell proliferation was improved for both investigated coatings whereas ALP

  2. Single-crystal CVD diamond detector for low-energy charged particles with energies ranging from 100 keV to 2 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Yuki Sato; Hiroyuki Murakami [Nishina Center for Accelerator-Based Science, The Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198, (Japan); Takehiro Shimaoka; Masakatsu Tsubota; Junichi, H. Kaneko [Graduate School of Engineering, Hokkaido University, N13, W8, Sapporo 060-8628, (Japan)

    2015-07-01

    The performance of a diamond detector made of a single-crystal diamond grown by chemical vapor deposition was studied for charged particles, having energies ranging from 100 keV to 2 MeV. Energy peaks of these low-energy ions were clearly observed. However, we observed that the pulse height for individual incident ion decreases with increasing atomic number of the ions. We estimated the charge collection efficiency of the generated charge carriers by charged particle incident. The charge collection above ∼95% is achieved for helium (He{sup +}) with the energy above 1.5 MeV. On the other hand, the charge collection efficiency for heavy-ions shows wrong values compared with that of He{sup +}, ∼70% for silicon (Si{sup +}) and 35 to 40% for gold (Au{sup 3+}), at the same incident energy range, respectively. (authors)

  3. Diamond Pixel Detectors and 3D Diamond Devices

    Science.gov (United States)

    Venturi, N.

    2016-12-01

    Results from detectors of poly-crystalline chemical vapour deposited (pCVD) diamond are presented. These include the first analysis of data of the ATLAS Diamond Beam Monitor (DBM). The DBM module consists of pCVD diamond sensors instrumented with pixellated FE-I4 front-end electronics. Six diamond telescopes, each with three modules, are placed symmetrically around the ATLAS interaction point. The DBM tracking capabilities allow it to discriminate between particles coming from the interaction point and background particles passing through the ATLAS detector. Also, analysis of test beam data of pCVD DBM modules are presented. A new low threshold tuning algorithm based on noise occupancy was developed which increases the DBM module signal to noise ratio significantly. Finally first results from prototypes of a novel detector using pCVD diamond and resistive electrodes in the bulk, forming a 3D diamond device, are discussed. 3D devices based on pCVD diamond were successfully tested with test beams at CERN. The measured charge is compared to that of a strip detector mounted on the same pCVD diamond showing that the 3D device collects significantly more charge than the planar device.

  4. Nano-inclusions in diamond: Evidence of diamond genesis

    Science.gov (United States)

    Wirth, R.

    2015-12-01

    The use of Focused Ion Beam technology (FIB) for TEM sample preparation introduced approximately 15 years ago revolutionized the application of TEM in Geosciences. For the first time, FIB enabled cutting samples for TEM use from exactly the location we are interested in. Applied to diamond investigation, this technique revealed the presence of nanometre-sized inclusions in diamond that have been simply unknown before. Nanoinclusions in diamond from different location and origin such as diamonds from the Lower and Upper Mantle, metamorphic diamonds (Kazakhstan, Erzgebirge, Bohemia), diamonds from ophiolites (Tibet, Mongolia, Xinjiang, Ural Mountains), diamonds from igneous rocks (Hawaii, Kamchatka) and impact diamonds (Popigai Crater, Siberia) have been investigated during the last 15 years. The major conclusion of all these TEM studies is, that the nanoinclusions, their phases and phase composition together with the micro- and nanostructure evidence the origin of diamond and genesis of diamond. We can discriminate Five different mechanisms of diamond genesis in nature are observed: Diamond crystallized from a high-density fluid (Upper mantle and metamorphic diamond). Diamond crystallized from carbonatitic melt (Lower mantle diamond). Diamond precipitates from a metal alloy melt (Diamond from ophiolites). Diamond crystallized by gas phase condensation or chemical vapour condensation (CVD) (Lavas from Kamchatka, xenoliths in Hawaiian lavas). Direct transformation of graphite into diamond.

  5. Growth and characterization of single-crystal CVD diamond for radiation detection applications; Synthese et caracterisation de diamants monocristallins pour applications de detecteur de rayonnements

    Energy Technology Data Exchange (ETDEWEB)

    Tranchant, N

    2008-01-15

    This work aimed at the study of the synthesis of single crystal diamond using the Microwave enhanced Chemical Vapour Deposition technique (MPCVD). The work enabled the development and optimisation of the growth conditions, from the study of the crystalline quality, of the material purity, and of its electronic properties. The assessment of the transport properties was the most determinant: the use of the time of flight (TOF) technique has enabled the measurement of the carrier mobilities and of their kinetic properties as a function of the temperature. When coupled with collected charge efficiency measurements, the work led to remarkable carrier mobility values obtained in the synthesised crystals (3000 cm{sup 2}.V-1.s{sup -1}). Prepared samples were mounted as detection devices and used successfully in real conditions for the monitoring of ultra-fast pulses, as well as for neutron fluency monitoring, and for medical dosimeters for radiotherapy applications. (author)

  6. Correlation between optical emission spectra and the process parameters of a 915 MHz microwave plasma CVD reactor used for depositing polycrystalline diamond coatings

    Indian Academy of Sciences (India)

    Awadesh Kumar Mallik; Sandip Bysakh; Someswar Dutta; Debabrata Basu

    2014-08-01

    In this paper, the hydrogen and hydrogen-methane mixed plasma have been generated inside a 33 cm diameter quartz bell jar with a low power (9 KW) and lower frequency 915 MHz microwave plasma chemical vapor deposition system. The reactor is being used for growing polycrystalline diamond (PCD) over large area (100 mm). The generated plasma is diagnosed by in situ optical emission spectroscopy method with wave length ranging from 200 to 900 nm. The effects of microwave power, chamber pressure and gas concentration on plasma characteristics have been studied in this work. Within the optical range, Balmer H, H, C2swan band and CH lines have been detected at the wavelengths of 655.95, 485.7, 515.82 and 430.17 nm, respectively. It has been observed that for hydrogen plasma, the amount of transition from hydrogen atom inner shell 3 to 2 (H) is almost constant with increasing microwave (MW) power (from 2000 to 2800 W) and pressure (from 15 to 30 Torr) initially, after that it increases with further increase of MW power and pressure, whereas, the transition from 4 to 2 (H) is slowly increased with increasing MW power and pressure. For hydrogen-methane plasma, intensities of C2 swan band, i.e., the transitions from D$^3\\Pi_\\text{g}$ to A$^3\\Pi_{\\mu}$ energy levels, are also increased with the increasing microwave power and reactor pressure. It has been observed that the radicals present in the plasma are affected by variation of different reactor parameters like pressure, MW power, CH4 concentration, etc.

  7. The INFN Micro-Si experiment: A silicon microdosimeter for assessing radiation quality of hadrontherapy beams

    Science.gov (United States)

    Agosteo, S.; Dal Corso, F.; Fazzi, A.; Gonella, F.; Introini, M. V.; Lippi, I.; Lorenzoli, M.; Pegoraro, M.; Pola, A.; Varoli, V.; Zotto, P.

    2013-07-01

    The MICRO-SI experiment, funded by INFN from 2008 up to 2010, aimed at developing a silicon microdosimeter capable of responding to neutrons and to hadron-therapy beams down to a few keV μm-1. The main goals which were achieved in the framework of this experiment are described in details. The detector, designed and fabricated by exploiting the monolithic telescope technology, demonstrated to provide charge confinement inside the micrometric sensitive volume, thus minimizing the field-funnelling effect. An innovative segmented telescope device was developed in order to have a silicon detector offering sensitive volume dimensions similar to those which can be simulated by a tissue-equivalent proportional counter (TEPC). The response of the segmented device to hadron beams was characterized with clinical protons and with 62 AMeV carbon ions at the INFN-Laboratori Nazionali del Sud (Catania, Italy). Irradiations with mono-energetic neutrons at the INFN-Laboratori Nazionali di Legnaro (Legnaro, Italy) were also performed. The agreement with the spectra measured with a TEPC is very satisfactory and gives confidence on the application of such a silicon device to assess the quality of hadrontherapy beams.

  8. Diamond detector technology: status and perspectives

    CERN Document Server

    Kagan, Harris; Artuso, M; Bachmair, F; Bäni, L; Bartosik, M; Beacham, J; Beck, H P; Bellini,, V; Belyaev, V; Bentele, B; Berdermann, E; Bergonzo, P; Bes, A; Brom, J-M; Bruzzi, M; Cerv, M; Chiodini, G; Chren, D; Cindro, V; Claus, G; Collot, J; Cumalat, J; Dabrowski, A; D'Alessandro, R; De Boer, W; Dehning, B; Dorfer, C; Dunser, M; Eremin, V; Eusebi, R; Forcolin, G; Forneris, J; Frais-Kölbl, H; Gan, K K; Gastal, M; Giroletti, C; Goffe, M; Goldstein, J; Golubev, A; Gorišek, A; Grigoriev, E; Grosse-Knetter, J; Grummer, A; Gui, B; Guthoff, M; Haughton, I; Hiti, B; Hits, D; Hoeferkamp, M; Hofmann, T; Hosslet, J; Hostachy, J-Y; Hügging, F; Hutton, C; Jansen, H; Janssen, J; Kanxheri, K; Kasieczka, G; Kass, R; Kassel, F; Kis, M; Kramberger, G; Kuleshov, S; Lacoste, A; Lagomarsino, S; Lo Giudice, A; Lukosi, E; Maazouzi, C; Mandic, I; Mathieu, C; Mcfadden, N; Menichelli, M; Mikuž, M; Morozzi, A; Moss, J; Mountain, R; Murphy, S; Muškinja, M; Oh, A; Oliviero, P; Passeri, D; Pernegger, H; Perrino, R; Picollo, F; Pomorski, M; Potenza, R; Quadt, A; Re, A; Reichmann, M; Riley, G; Roe, S; Sanz, D; Scaringella, M; Schaefer, D; Schmidt, C J; Schnetzer, S; Schreiner, T; Sciortino, S; Scorzoni, A; Seidel, S; Servoli, L; Sopko, B; Sopko, V; Spagnolo, S; Spanier, S; Stenson, K; Stone, R; Sutera, C; Taylor, Aaron; Traeger, M; Tromson, D; Trischuk, W; Tuve, C; Uplegger, L; Velthuis, J; Venturi, N; Vittone, E; Wagner, Stephen; Wallny, R; Wang, J C; Weingarten, J; Weiss, C; Wengler, T; Wermes, N; Yamouni, M; Zavrtanik, M

    2017-01-01

    The status of material development of poly-crystalline chemical vapor deposition (CVD) diamond is presented. We also present beam test results on the independence of signal size on incident par-ticle rate in charged particle detectors based on un-irradiated and irradiated poly-crystalline CVD diamond over a range of particle fluxes from 2 kHz/cm2 to 10 MHz/cm2. The pulse height of the sensors was measured with readout electronics with a peaking time of 6 ns. In addition the first beam test results from 3D detectors made with poly-crystalline CVD diamond are presented. Finally the first analysis of LHC data from the ATLAS Diamond Beam Monitor (DBM) which is based on pixelated poly-crystalline CVD diamond sensors bump-bonded to pixel readout elec-tronics is shown.

  9. Untersuchungen zum Fräsen mit CVD-diamantbeschichteten Werkzeugen

    OpenAIRE

    Grams, Jörg

    2004-01-01

    CVD-diamond coatings on cemented carbide substrates have undergone significant developments in recent years. Former CVD-diamond coated tools failed in metal cutting applications due to severe flaking of the diamond layer. Thus, first industrial applications had been restricted to machining of graphite, fibre reinforced plastics and green compacts made of cemented carbide respectively of ceramics. The field of application is widened nowadays towards machining of non ferrous metallic materials ...

  10. Ionoluminescence of diamond, synthetic diamond and simulants

    Energy Technology Data Exchange (ETDEWEB)

    Calvo del Castillo, H. [Departamento de Geologia y Geoquimica, Facultad de Ciencias, Universidad Autonoma de Madrid, Ctra de Colmenar km 15, Madrid 27049 (Spain); Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Circuito de la Investigacion Cientifica s/n, Ciudad Universitaria, Ciudad de Mexico 04519, Mexico, DF (Mexico); Ruvalcaba-Sil, J.L. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Circuito de la Investigacion Cientifica s/n, Ciudad Universitaria, Ciudad de Mexico 04519, Mexico, DF (Mexico); Barboza-Flores, M. [Centro de Investigacio en Fisica, Universidad de Sonora, Apartado postal 5-088, Hermosillo, Sonora 83190 (Mexico); Belmont, E. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Circuito de la Investigacion Cientifica s/n, Ciudad Universitaria, Ciudad de Mexico 04519, Mexico, DF (Mexico); Calderon, T. [Departamento de Geologia y Geoquimica, Facultad de Ciencias, Universidad Autonoma de Madrid, Ctra de Colmenar km 15, Madrid 27049 (Spain)], E-mail: tomas.calderon@uam.es

    2007-09-21

    Ionoluminescence (IL) spectra of diamond (natural samples and synthetic CVD) and its more common synthetic simulates such as sapphire, spinel, cubic zirconia, strontium titanate and yttrium aluminium garnet (YAG: Er) will be discussed here in order to support some criteria that will allow to distinguish between them. While diamond shows emission bands due to nitrogen defects, simulants feature d-transition metals and rare earths such as Cr{sup 3+}, Mn{sup 2+}, Fe{sup 3+}, Ti{sup 3+} and Er{sup 3+} emissions.

  11. Mechanically induced degradation of diamond

    CERN Document Server

    Bouwelen, F V

    1996-01-01

    bombardment a mechanically induced graphitisation, as opposed to a thermally activated transformation, may occur locally on collision with the CVD diamond. Two types of diamond-graphite interfaces were observed: (111) planes of diamond parallel to the a-b planes of graphite and (111) planes of diamond, smoothly within the plane, connected to a-b planes of graphite. The thesis concludes with a summary of the results, conclusions and recommendations for further work. This thesis deals with the wear of diamond occurring during frictional sliding contact between diamonds. In the introduction, a literature survey on friction, wear and polishing behaviour of diamond, with some emphasis on the anisotropy, is presented and earlier work is discussed. A review of the existing theories is given, a new hypothesis is proposed and key-experiments for verification are identified. Electron microscopical techniques such as High Resolution Electron Microscopy (HREM) imaging and Electron Energy Loss Spectroscopy are described a...

  12. Diamond sensors for future high energy experiments

    Energy Technology Data Exchange (ETDEWEB)

    Bachmair, Felix, E-mail: bachmair@phys.ethz.ch

    2016-09-21

    With the planned upgrade of the LHC to High-Luminosity-LHC [1], the general purpose experiments ATLAS and CMS are planning to upgrade their innermost tracking layers with more radiation tolerant technologies. Chemical Vapor Deposition CVD diamond is one such technology. CVD diamond sensors are an established technology as beam condition monitors in the highest radiation areas of all LHC experiments. The RD42-collaboration at CERN is leading the effort to use CVD diamond as a material for tracking detectors operating in extreme radiation environments. An overview of the latest developments from RD42 is presented including the present status of diamond sensor production, a study of pulse height dependencies on incident particle flux and the development of 3D diamond sensors.

  13. Diamond sensors for future high energy experiments

    Science.gov (United States)

    Bachmair, Felix

    2016-09-01

    With the planned upgrade of the LHC to High-Luminosity-LHC [1], the general purpose experiments ATLAS and CMS are planning to upgrade their innermost tracking layers with more radiation tolerant technologies. Chemical Vapor Deposition CVD diamond is one such technology. CVD diamond sensors are an established technology as beam condition monitors in the highest radiation areas of all LHC experiments. The RD42-collaboration at CERN is leading the effort to use CVD diamond as a material for tracking detectors operating in extreme radiation environments. An overview of the latest developments from RD42 is presented including the present status of diamond sensor production, a study of pulse height dependencies on incident particle flux and the development of 3D diamond sensors.

  14. Diagnostic Techniques Used to Study Chemical-Vapor-Deposited Diamond Films

    Science.gov (United States)

    Miyoshi, Kazuhisa

    2000-01-01

    The advantages and utility of chemical-vapor-deposited (CVD) diamond as an industrial ceramic can only be realized if the price and quality are right. Until recently, this technology was of interest only to the academic and basic research community. However, interest has grown because of advances made by leading CVD diamond suppliers: 1) Reduction of the cost of CVD polycrystalline diamond deposition below $5/carat ($8/sq cm); 2) Installation of production capacity; 3) Epitaxial growth of CVD single-crystal diamond. Thus, CVD diamond applications and business are an industrial reality. At present, CVD diamond is produced in the form of coatings or wafers. CVD diamond film technology offers a broader technological potential than do natural and high-pressure synthetic diamonds because size, geometry, and eventually cost will not be as limiting. Now that they are cost effective, diamond coatings - with their extreme properties - can be used in a variety of applications. Diamond coatings can improve many of the surface properties of engineering substrate materials, including erosion, corrosion, and wear resistance. Examples of actual and potential applications, from microelectromechanical systems to the wear parts of diamond coatings and related superhard coatings are described. For example, diamond coatings can be used as a chemical and mechanical barrier for the space shuttles check valves, particularly on the guide pins and seat assemblies.

  15. Homo-epitaxial diamond film growth on ion implanted diamond substrates

    Energy Technology Data Exchange (ETDEWEB)

    Weiser, P.S.; Prawer, S.; Nugent, K.W.; Bettiol, A.A.; Kostidis, L.I.; Jamieson, D.N. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1996-12-31

    The nucleation of CVD diamond is a complicated process, governed by many interrelated parameters. In the present work we attempt to elucidate the effect of strain on the growth of a homo-epitaxial CVD diamond. We have employed laterally confined high dose (MeV) Helium ion implantation to produce surface swelling of the substrate. The strain is enhanced by the lateral confinement of the implanted region to squares of 100 x 100 {mu}m{sup 2}. After ion implantation, micro-Raman spectroscopy was employed to map the surface strain. The substrates were then inserted into a CVD reactor and a CVD diamond film was grown upon them. Since the strained regions were laterally confined, it was then possible to monitor the effect of strain on diamond nucleation. The substrates were also analysed using Rutherford Backscattering Spectroscopy (RBS), Proton induced X-ray Emission (PIXE) and Ion Beam induced Luminescence (IBIL). 7 refs., 5 figs.

  16. Industrial diamond

    Science.gov (United States)

    Olson, D.W.

    2001-01-01

    An overview of the industrial diamond industry is provided. More than 90 percent of the industrial diamond consumed in the U.S. and the rest of the world is manufactured diamond. Ireland, Japan, Russia, and the U.S. produce 75 percent of the global industrial diamond output. In 2000, the U.S. was the largest market for industrial diamond. Industrial diamond applications, prices for industrial diamonds, imports and exports of industrial diamonds, the National Defense Stockpile of industrial diamonds, and the outlook for the industrial diamond market are discussed.

  17. 直流电弧等离子体喷射CVD硼掺杂金刚石薄膜的制备及电化学性能研究%Electrochemical Properties of Boron Doped Diamond Films Prepared by DC Arc Plasma Jet CVD

    Institute of Scientific and Technical Information of China (English)

    张聪聪; 戴玮; 朱宁; 尹振超; 吴小国; 曲长庆

    2012-01-01

    Boron doped diamond films on silicon ( BDD) substrates were deposited by DC ARC Plasma Jet CVD (Chemical Vapor Deposition) , SEM, XRD and Raman spectroscopy were employed to analyze the morphology, crystal structure and film quality. The SEM and XRD show jointly that the samples are high-quality polycrystalline diamond films composed of micro meter-sized grains. The Raman spectrum show the 1126 cm-1,1336 cm -1and 1560 cm-1, respectively corresponds to peak due to boron incorporation, sp3 carbon peak ,and sp2 carbon peak. Study the effects of pressure and (100) BDD films were deposited at the pressure of 5500 Pa. The resistivity and carrier concentration of the (111) films measured by the Hall system, respectively corresponds to 0. 0095 Ω · cm and 1. 1 × 1020 cm-3. The electrochemical behaviors of the boron-doped diamond film electrode in sodium sulfate solution, potassium ferrocyanide/ potassium ferricyanide solution and dopamine solution are studied. The results show that the' diamond film electrode have a wide electrochemical window of about 4 V and a low background current close to zero in the aqua solution, meanwhile they have a high sensitivity, good stability and reversibility in the dopamine detection experiment which makes boron-doped diamond film obtained by DC ARC Plasma Jet CVD being an excellent material of electrochemical electrode.%采用直流电弧等离子体喷射CVD(Chemical Vapor Deposition)法在硅(100)衬底上制备了(111)占优的掺硼金刚石(BDD)薄膜,研究了压强对薄膜生长的影响,在压强为5500Pa时得到了(100)占优的金刚石薄膜,并用SEM、XRD及拉曼光谱分析了薄膜的表面形貌、晶体结构、薄膜品质.测试结果表明,掺硼金刚石膜具有较好的成膜质量.霍尔测试表明BDD的电阻率为0.0095Ω·cm,载流子浓度为1.1×1020 cm-3;研究了BDD薄膜电极在硫酸钠空白底液、铁氰化钾/亚铁氰化钾溶液和多巴胺溶液中的循环伏安曲线(CVs),发现该金刚

  18. EXELFS analysis of natural diamond and diamond films on Si substrates

    Energy Technology Data Exchange (ETDEWEB)

    Moller, A.D. [Centro de Investigacion Cientifica y de Educacion Superior de Ensenada (Mexico); Araiza, L.C.; Borja, M.A. [Universidad Nacional Autonoma de Mexico, Ensenada (Mexico)

    1996-12-31

    In this work, we report the EXELFS results obtained from a polycrystalline diamond film grown on smooth silicon substrates using the Hot Filament Chemical Vapor Deposition (HF-CVD) technique in a two-step deposition process published elsewhere. In order to evaluate the quality of the thin film obtained, these results were compared with results obtained from natural diamond.

  19. Nucleation, growth and acoustic properties of thin film diamond

    CERN Document Server

    Whitfield, M D

    1999-01-01

    emission spectroscopy has been used to study the influence of substrate bias on the microwave plasma during diamond nucleation. Surface acoustic wave (SAW) devices have recently emerged as promising near term applications for currently available CVD diamond however little is known about the propagation of acoustic waves in this material; a detailed study of the influence of film characteristics on acoustic propagation in free standing CVD diamond films has been undertaken using the techniques of laser ultrasonic analysis. The unusual combination of extreme properties possessed by diamond could benefit a wide range of applications. Thus far practical utilisation of this material has remained difficult and consequently limited; natural and synthetic crystals are unsuitable forms for many uses; particularly electronic applications which ideally require large area, single crystal substrates. Emerging CVD methods for the growth of thin film diamond offer a practical alternative; although nucleation on non-diamond ...

  20. Investigation of the Millimeter-Wave Plasma Assisted CVD Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Vikharev, A; Gorbachev, A; Kozlov, A; Litvak, A; Bykov, Y; Caplan, M

    2005-07-21

    A polycrystalline diamond grown by the chemical vapor deposition (CVD) technique is recognized as a unique material for high power electronic devices owing to unrivaled combination of properties such as ultra-low microwave absorption, high thermal conductivity, high mechanical strength and chemical stability. Microwave vacuum windows for modern high power sources and transmission lines operating at the megawatt power level require high quality diamond disks with a diameter of several centimeters and a thickness of a few millimeters. The microwave plasma-assisted CVD technique exploited today to produce such disks has low deposition rate, which limits the availability of large size diamond disk windows. High-electron-density plasma generated by the millimeter-wave power was suggested for enhanced-growth-rate CVD. In this paper a general description of the 30 GHz gyrotron-based facility is presented. The output radiation of the gyrotron is converted into four wave-beams. Free localized plasma in the shape of a disk with diameter much larger than the wavelength of the radiation is formed in the intersection area of the wave-beams. The results of investigation of the plasma parameters, as well as the first results of diamond film deposition are presented. The prospects for commercially producing vacuum window diamond disks for high power microwave devices at much lower costs and processing times than currently available are outlined.

  1. Lubrication by Diamond and Diamondlike Carbon Coatings

    Science.gov (United States)

    Miyoshi, Kazuhisa

    1997-01-01

    Regardless of environment (ultrahigh vacuum, humid air, dry nitrogen, or water), ion-beam-deposited diamondlike carbon (DLC) and nitrogen-ion-implanted, chemical-vapor-deposited (CVD) diamond films had low steady-state coefficients of friction (less than 0.1) and low wear rates (less than or equal to 10(exp -6)cu mm/N(dot)m). These films can be used as effective wear-resistant, self-lubricating coatings regardless of environment. On the other hand, as-deposited, fine-grain CVD diamond films; polished, coarse-grain CVD diamond films; and polished and then fluorinated, coarse-grain CVD diamond films can be used as effective wear-resistant, self-lubricating coatings in humid air, in dry nitrogen, and in water, but they had a high coefficient of friction and a high wear rate in ultrahigh vacuum. The polished, coarse-grain CVD diamond film revealed an extremely low wear rate, far less than 10(exp 10) cu mm/N(dot)m, in water.

  2. Electromagnetic Radiation Hardness of Diamond Detectors

    CERN Document Server

    Behnke, T; Ghodbane, N; Imhof, A; Martínez, C; Zeuner, W

    2002-01-01

    The behavior of artificially grown CVD diamond films under intense electromagnetic radiation has been studied. The properties of irradiated diamond samples have been investigated using the method of thermally stimulated current and by studying their charge collection properties. Diamonds have been found to remain unaffected after doses of 6.8 MGy of 10 keV photons and 10 MGy of MeV-range photons. This observation makes diamond an attractive detector material for a calorimeter in the very forward region of the proposed TESLA detector.

  3. Effect of Mo ion-implantation on the adhesion of diamond coatings

    CERN Document Server

    Yang Shie; Wang Xiao Ping; Li Hui; Ma Bing Xian; Qin Guang Yong; Zhang Bing Lin

    2002-01-01

    Diamond coatings were deposited on the cobalt-cemented tungsten carbide (YG6) substrates, which have been implanted with Mo ions, by microwave plasma CVD (MPCVD) method. The effect of ion-implantation on the adhesion of diamond coatings was studied. The results showed that the chemical compositions of cemented carbide substrate surfaces change obviously after Mo ion-implantation; and the adhesion strength between the CVD diamond coatings and the substrates implanted with Mo ions in proper concentration is improved remarkably

  4. Diamond Detectors as Beam Monitors

    CERN Document Server

    Dehning, B; Dobos, D; Pernegger, H; Griesmayer, E

    2010-01-01

    CVD diamond particle detectors are already in use in the CERN experiments ATLAS, CMS, LHCb and ALICE and at various particle accelerator laboratories in USA and Japan. This is a proven technology with high radiation tolerance and very fast signal read-out. It can be used for measuring single-particles as well as for high-intensity particle cascades, for timing measurements on the nanosecond scale and for beam protection systems. The radiation tolerance is specified with 10 MGy.

  5. A Comparative Study of Three Different Chemical Vapor Deposition Techniques of Carbon Nanotube Growth on Diamond Films

    Directory of Open Access Journals (Sweden)

    Betty T. Quinton

    2013-01-01

    Full Text Available This paper compares between the methods of growing carbon nanotubes (CNTs on diamond substrates and evaluates the quality of the CNTs and the interfacial strength. One potential application for these materials is a heat sink/spreader for high-power electronic devices. The CNTs and diamond substrates have a significantly higher specific thermal conductivity than traditional heat sink/spreader materials making them good replacement candidates. Only limited research has been performed on these CNT/diamond structures and their suitability of different growth methods. This study investigates three potential chemical vapor deposition (CVD techniques for growing CNTs on diamond: thermal CVD (T-CVD, microwave plasma-enhanced CVD (MPE-CVD, and floating catalyst thermal CVD (FCT-CVD. Scanning electron microscopy (SEM and high-resolution transmission electron microscopy (TEM were used to analyze the morphology and topology of the CNTs. Raman spectroscopy was used to assess the quality of the CNTs by determining the ID/IG peak intensity ratios. Additionally, the CNT/diamond samples were sonicated for qualitative comparisons of the durability of the CNT forests. T-CVD provided the largest diameter tubes, with catalysts residing mainly at the CNT/diamond interface. The MPE-CVD process yielded non uniform defective CNTs, and FCT-CVD resulted in the smallest diameter CNTs with catalyst particles imbedded throughout the length of the nanotubes.

  6. Technology for boron-doped layers formation on the diamond

    Directory of Open Access Journals (Sweden)

    Zyablyuk K. N.

    2012-10-01

    Full Text Available The authors investigated natural type IIa diamond crystals and CVD diamond films. The article presents electrophysical parameters of the structures obtained in different modes of ion implantation of boron into the crystal with further annealing. Parameters of the crystals with a high nitrogen impurity density indicate that they can be used for the manufacture of microwave field-effect transistors operating at room temperature. CVD diamond films doped with boron during the growth process also have the required for MOSFET manufacture carrier mobility. However, due to the high activation energy of boron, the required channel conductivity is achieved at high operating temperatures.

  7. Evaluation on residual stresses of silicon-doped CVD diamond films using X-ray diffraction and Raman spectroscopy%CVD掺硅金刚石残余应力的X射线衍射和拉曼光谱分析

    Institute of Scientific and Technical Information of China (English)

    陈苏琳; 沈彬; 张建国; 王亮; 孙方宏

    2012-01-01

    采用X射线衍射(XRD)和拉曼光谱2种方法测量了不同硅碳比的CVD掺硅金刚石薄膜的残余应力.采用偏压增强热丝化学气相沉积装置在硬质合金基底上制备了掺硅金刚石薄膜,将正硅酸乙酯以不同的体积比溶解在丙酮中以使得反应气体中的硅碳比从0.1%变化到1.4%,从而控制掺硅金刚石薄膜的掺杂浓度.SEM和XRD的表征结果显示,随着硅掺杂浓度的增加,金刚石薄膜的晶粒尺寸减小,而金刚石(110)的晶面则逐渐占优.XRD法是测量入射角从0°到45°变化时对应的金刚石(220)面XRD衍射峰,并采用sin2ψ方法计算掺硅金刚石薄膜的残余应力.拉曼谱法则是通过检测金刚石特征峰偏移1332 cm-1位置的偏移量来测量残余应力.2种方法测得的残余应力随着硅掺杂含量的升高显示出良好的一致性,所有的硅掺杂金刚石的残余应力均为压应力,Si/C摩尔比为0.1%的薄膜具有最高的残余应力,为~1.75 GPa(拉曼谱法)或~2.3 GPa(XRD法).随着硅掺杂浓度的进一步升高,薄膜的残余应力则稳定在~1.3 GPa左右.%The effect of silicon doping on the residual stress of CVD diamond films is examined using both X-ray diffraction(XRD)analysis and Raman spectroscopy measurements.The examined Si-doped diamond films are deposited on WC-Co substrates in a home-made bias-enhanced HFCVD apparatus.Ethyl silicate(Si(OC2H5)4)is dissolved in acetone to obtain various Si/C mole ratio ranging from 0.1% to 1.4% in the reaction gas.Characterizations with SEM and XRD indicate increasing silicon concentration may result in grain size decreasing and diamond [110] texture becoming dominant.The residual stress values of as-deposited Si-doped diamond films are evaluated by both sin2ψ method,which measures the(220)diamond Bragg diffraction peaks using XRD,with ψ-values ranging from 0°to 45°,and Raman spectroscopy,which detects the diamond Raman peak shift from the natural diamond line at

  8. Developing the Beijing CVD

    Institute of Scientific and Technical Information of China (English)

    LU JINGXIAN

    2006-01-01

    @@ Slowly but surely, the high-end villa property in Beijing is gaining new momentum. Limited amounts of new properties, rising prices and increasing demand will be the trend in the villa market in 2006, real estate experts predict. Among them, the exclusive Central Villa District(CVD), a top-tier villa area along the Wenyu River in northeast Beijing, has emerged as a hot spot of the market.

  9. Nanostructured Diamond Device for Biomedical Applications.

    Science.gov (United States)

    Fijalkowski, M; Karczemska, A; Lysko, J M; Zybala, R; KozaneckI, M; Filipczak, P; Ralchenko, V; Walock, M; Stanishevsky, A; Mitura, S

    2015-02-01

    Diamond is increasingly used in biomedical applications because of its unique properties such as the highest thermal conductivity, good optical properties, high electrical breakdown voltage as well as excellent biocompatibility and chemical resistance. Diamond has also been introduced as an excellent substrate to make the functional microchip structures for electrophoresis, which is the most popular separation technique for the determination of analytes. In this investigation, a diamond electrophoretic chip was manufactured by a replica method using a silicon mold. A polycrystalline 300 micron-thick diamond layer was grown by the microwave plasma-assisted CVD (MPCVD) technique onto a patterned silicon substrate followed by the removal of the substrate. The geometry of microstructure, chemical composition, thermal and optical properties of the resulting free-standing diamond electrophoretic microchip structure were examined by CLSM, SFE, UV-Vis, Raman, XRD and X-ray Photoelectron Spectroscopy, and by a modified laser flash method for thermal property measurements.

  10. Early diamond making at General Electric

    Science.gov (United States)

    Strong, H. M.

    1989-09-01

    This is an account of how GE's early interest in a new super-hard metal, cobalt cemented tungsten carbide, for drawing tungsten lamp filament wire, led to a broader interest in the realm of super pressure and to diamond synthesis. P. W. Bridgman at Harvard University had demonstrated the new metal's (``Carboloy'') ability to generate pressures of 100 000 atm (100 kbars). Armed with this new capability, GE initiated a diamond project in 1951. In December 1954 two synthesized diamonds emerged in a marginal experiment that for a while could not be reproduced. Nevertheless, that experiment gave the critical clue to the process that now provides 90% of the world's industrial diamond needs. The high-pressure high-temperature process (HPHT) together with the new carbon vapor deposition process (CVD) brings diamonds' unique and valuable properties to applications requiring crystals tailored to fit specific needs.

  11. Charge multiplication effect in thin diamond films

    Energy Technology Data Exchange (ETDEWEB)

    Skukan, N., E-mail: nskukan@irb.hr; Grilj, V.; Sudić, I.; Jakšić, M. [Division of Experimental Physics, Ruđer Bošković Institute, 10000 Zagreb (Croatia); Pomorski, M. [CEA-LIST, Diamond Sensors Laboratory, Gif-sur-Yvette F-91191 (France); Kada, W.; Kambayashi, Y.; Andoh, Y. [Division of Electronics and Informatics, Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515 (Japan); Makino, T.; Onoda, S.; Sato, S.; Ohshima, T.; Kamiya, T. [National Institutes for Quantum and Radiological Science and Technology, Takasaki, Gunma 370-1292 (Japan)

    2016-07-25

    Herein, we report on the enhanced sensitivity for the detection of charged particles in single crystal chemical vapour deposition (scCVD) diamond radiation detectors. The experimental results demonstrate charge multiplication in thin planar diamond membrane detectors, upon impact of 18 MeV O ions, under high electric field conditions. Avalanche multiplication is widely exploited in devices such as avalanche photo diodes, but has never before been reproducibly observed in intrinsic CVD diamond. Because enhanced sensitivity for charged particle detection is obtained for short charge drift lengths without dark counts, this effect could be further exploited in the development of sensors based on avalanche multiplication and radiation detectors with extreme radiation hardness.

  12. 77 FR 47362 - Diamond Sawblades and Parts Thereof From the People's Republic of China: Rescission of...

    Science.gov (United States)

    2012-08-08

    .... FOR FURTHER INFORMATION CONTACT: Yang Jin Chun, AD/CVD Operations, Office 1, Import Administration... investigate further serious allegations of fraud in the concurrent administrative review of diamond sawblades...

  13. Investigations of high mobility single crystal chemical vapor deposition diamond for radiotherapy photon beam monitoring

    Science.gov (United States)

    Tromson, D.; Descamps, C.; Tranchant, N.; Bergonzo, P.; Nesladek, M.; Isambert, A.

    2008-03-01

    The intrinsic properties of diamond make this material theoretically very suitable for applications in medical physics. Until now ionization chambers have been fabricated from natural stones and are commercialized by PTW, but their fairly high costs and long delivery times have often limited their use in hospital. The properties of commercialized intrinsic polycrystalline diamond were investigated in the past by many groups. The results were not completely satisfactory due to the nature of the polycrystalline material itself. In contrast, the recent progresses in the growth of high mobility single crystal synthetic diamonds prepared by chemical vapor deposition (CVD) technique offer new alternatives. In the framework of the MAESTRO project (Methods and Advanced Treatments and Simulations for Radio Oncology), the CEA-LIST is studying the potentialities of synthetic diamond for new techniques of irradiation such as intensity modulated radiation therapy. In this paper, we present the growth and characteristics of single crystal diamond prepared at CEA-LIST in the framework of the NoRHDia project (Novel Radiation Hard CVD Diamond Detector for Hadrons Physics), as well as the investigations of high mobility single crystal CVD diamond for radiotherapy photon beam monitoring: dosimetric analysis performed with the single crystal diamond detector in terms of stability and repeatability of the response signal, signal to noise ratio, response speed, linearity of the signal versus the absorbed dose, and dose rate. The measurements performed with photon beams using radiotherapy facilities demonstrate that single crystal CVD diamond is a good alternative for air ionization chambers for beam quality control.

  14. Recent results on the development of radiation-hard diamond detectors

    CERN Document Server

    Conway, J S; Bauer, C; Berdermann, E; Bergonzo, P; Bogani, F; Borchi, E; Brambilla, A; Bruzzi, Mara; Colledani, C; Dabrowski, W; Da Graca, J; Delpierre, P A; Deneuville, A; Dulinski, W; van Eijk, B; Fallou, A; Fizzotti, F; Foulon, F; Friedl, M; Gan, K K; Gheeraert, E; Grigoriev, E; Hallewell, G D; Hall-Wilton, R; Han, S; Hartjes, F G; Hrubec, Josef; Husson, D; Jamieson, D; Kagan, H; Kania, D R; Kaplon, J; Karl, C; Kass, R; Knöpfle, K T; Krammer, Manfred; Lo Giudice, A; Lü, R; Manfredi, P F; Manfredotti, C; Marshall, R D; Meier, D; Mishina, M; Oh, A; Pan, L S; Palmieri, V G; Pernicka, Manfred; Peitz, A; Pirollo, S; Plano, R; Polesello, P; Prawer, S; Pretzl, Klaus P; Procario, M; Re, V; Riester, J L; Roe, S; Roff, D G; Rudge, A; Russ, J; Schnetzer, S; Sciortino, S; Somalwar, S V; Speziali, V; Stelzer, H; Stone, R; Suter, B; Tapper, R J; Tesarek, R; Thomson, G B; Trawick, M; Trischuk, W; Vittone, E; Walsh, A M; Wedenig, R; Weilhammer, Peter; White, C; Ziock, H J; Zöller, M

    1999-01-01

    Charged particle detectors made from chemical vapor deposition (CVD) diamond have radiation hardness greatly exceeding that of silicon- based detectors. The CERN-based RD42 Collaboration has developed and tested CVD diamond microstrip and pixel detectors with an eye to their application in the intense radiation environment near the interaction region of hadron colliders. This paper presents recent results from tests of these detectors. (4 refs).

  15. Non-classical crystallization of thin films and nanostructures in CVD and PVD processes

    CERN Document Server

    Hwang, Nong Moon

    2016-01-01

    This book provides a comprehensive introduction to a recently-developed approach to the growth mechanism of thin films and nanostructures via chemical vapour deposition (CVD). Starting from the underlying principles of the low pressure synthesis of diamond films, it is shown that diamond growth occurs not by individual atoms but by charged nanoparticles. This newly-discovered growth mechanism turns out to be general to many CVD and some physical vapor deposition (PVD) processes. This non-classical crystallization is a new paradigm of crystal growth, with active research taking place on growth in solution, especially in biomineralization processes. Established understanding of the growth of thin films and nanostructures is based around processes involving individual atoms or molecules. According to the author’s research over the last two decades, however, the generation of charged gas phase nuclei is shown to be the rule rather than the exception in the CVD process, and charged gas phase nuclei are actively ...

  16. Diamond Nanophotonics

    CERN Document Server

    Aharonovich, Igor

    2014-01-01

    The burgeoning field of nanophotonics has grown to be a major research area, primarily because of the ability to control and manipulate single quantum systems (emitters) and single photons on demand. For many years studying nanophotonic phenomena was limited to traditional semiconductors (including silicon and GaAs) and experiments were carried out predominantly at cryogenic temperatures. In the last decade, however, diamond has emerged as a new contender to study photonic phenomena at the nanoscale. Offering plethora of quantum emitters that are optically active at room temperature and ambient conditions, diamond has been exploited to demonstrate super-resolution microscopy and realize entanglement, Purcell enhancement and other quantum and classical nanophotonic effects. Elucidating the importance of diamond as a material, this review will highlight the recent achievements in the field of diamond nanophotonics, and convey a roadmap for future experiments and technological advancements.

  17. Fabrication of thin diamond membranes by using hot implantation and ion-cut methods

    Science.gov (United States)

    Suk, Jaekwon; Kim, Hyeongkwon; Lim, Weon Cheol; Yune, Jiwon; Moon, Sung; Eliades, John A.; Kim, Joonkon; Lee, Jaeyong; Song, Jonghan

    2017-03-01

    A thin (2 μm) and relatively large area (3 × 3 mm2) diamond membrane was fabricated by cleaving a surface from a single crystal chemical vapor deposition (CVD) diamond wafer (3 × 3 mm2× 300 μm) using a hot implantation and ion-cut method. First, while maintaining the CVD diamond at 400 °C, a damage zone was created at a depth of 2.3 μm underneath the surface by implanting 4 MeV carbon ions into the diamond in order to promote membrane cleavage (hot implantation). According to TEM data, hot implantation reduces the thickness of the implantation damage zone by about a factor of 10 when compared to implanting carbon ions with the CVD diamond at room temperature (RT). In order to recover crystallinity, the implanted sample was then annealed at 850 °C. Next, 380 keV hydrogen ions were implanted into the sample to a depth of 2.3 μm below the surface with the CVD diamond at RT. After annealing at 850 °C, the CVD diamond surface layer was cleaved at the damage-zone due to internal pressure from H2 gas arising from the implanted hydrogen (ion-cut). A thin layer of graphite (˜300 nm) on the cleavage surface, arising from the implanted carbon, was removed by O2 annealing. This technique can potentially be used to produce much larger area membranes of variable thickness.

  18. Diamond MEMS: wafer scale processing, devices, and technology insertion

    Science.gov (United States)

    Carlisle, J. A.

    2009-05-01

    Diamond has long held the promise of revolutionary new devices: impervious chemical barriers, smooth and reliable microscopic machines, and tough mechanical tools. Yet it's been an outsider. Laboratories have been effectively growing diamond crystals for at least 25 years, but the jump to market viability has always been blocked by the expense of diamond production and inability to integrate with other materials. Advances in chemical vapor deposition (CVD) processes have given rise to a hierarchy of carbon films ranging from diamond-like carbon (DLC) to vapor-deposited diamond coatings, however. All have pros and cons based on structure and cost, but they all share some of diamond's heralded attributes. The best performer, in theory, is the purest form of diamond film possible, one absent of graphitic phases. Such a material would capture the extreme hardness, high Young's modulus and chemical inertness of natural diamond. Advanced Diamond Technologies Inc., Romeoville, Ill., is the first company to develop a distinct chemical process to create a marketable phase-pure diamond film. The material, called UNCD® (for ultrananocrystalline diamond), features grain sizes from 3 to 300 nm in size, and layers just 1 to 2 microns thick. With significant advantages over other thin films, UNCD is designed to be inexpensive enough for use in atomic force microscopy (AFM) probes, microelectromechanical machines (MEMS), cell phone circuitry, radio frequency devices, and even biosensors.

  19. Diamond detector - material science, design and application

    Science.gov (United States)

    Gaowei, Mengjia

    Modern synchrotrons, such as the NSLS-II, will enable unprecedented science by having extremely high brightness and flux with exceptional beam stability. These capabilities create a harsh and demanding environment for measuring the characteristics of the x-ray beam. In many cases, existing measurement techniques fail completely, requiring the development of new detectors which can meet the demands of the synchrotron. The combination of diamond properties ranked diamond an appealing candidate in the field of radiation detection in extreme conditions and it has been used as x-ray sensor material for decades. However, only until the development of chemical vapor deposition (CVD) process in the synthesis of diamond that has it been considered for wider applications in the state-of-art synchrotron light sources as part of beamline diagnostics, including the detection of x-ray beam flux and position. While defects and dislocations in CVD grown single crystal diamonds are inevitable, there are solutions in other aspects of a device fabrication to compensate this technological downside, including improving device performance in engineering diamond surface electrode materials and patterns and slicing and polishing diamond plates into thinner pieces. The content of this dissertation summarizes our effort in addressing several problems we encounter in the process of design and fabrication of single crystal CVD diamond based electronic devices. In order to study the generation of post-anneal photoconductive gain in our devices we have discussed in section 3 and 4 the two criteria for the observation of photoconductive current. In section 3 we reveal the correlation between structural defects in diamond and the post-anneal photoconductive regions. Section 4 introduces the measurements of hard x-ray photoelectron spectroscopy (HAXPES) we applied to investigate the diamond-metal Schottky barrier height for several metals and diamond surface terminations. The position of the

  20. [Manufacture of diamond blades via microsystem technology].

    Science.gov (United States)

    Spraul, Christoph W; Ertl, Stephan; Strobel, Stefan; Gretzschel, Ralph; Schirmer, Enrico; Rösch, Rudolf; Lingenfelder, Christian; Lang, Gerhard K

    2003-04-01

    The application of diamond knives has steadily increased in ophthalmic surgery. However, the geometry of the blade, its thickness and the sharpness of the cutting edge are limited by the abrasive diamond polishing process, e. g. the crystalline morphology of the bulk material and the grinding powder used. A new generation of diamond blades is presented herewith allowing free choice of blade shape and thickness and possessing excellent sharpness due to a new polishing process. The new production method is based on a high-quality CVD (chemical vapour deposition) diamond film of some tenths of microns thickness, deposited on a silicon wafer as microchip technology. The mechanical properties of this synthetic diamond film are almost equal to those of a natural diamond and the surface of this film is mirror-like after deposition without requiring post-polishing. The shape of the blade can be freely defined and is transferred into the diamond film by a plasma polishing process adopted from microsystem technology. The new production method results in highly reproducible diamond blades. Concave blades and round shapes can now be realised without the restrictions of the conventional production process. The force-free fabrication method even allows realisation of miniaturized blades (e. g. width production. Plasma polishing by means of gas atoms results in extreme sharpness with the cutting edge radius in the range of approx. 3 nm. Utilising microsystem technology we were able to manufacture reproducible artificial diamond blades. The new process offers for the first time surgeons a possibility of designing blades with a geometry close to their personal needs. Furthermore, the potential of facet-free ergonomically shaped diamond blades may stimulate further improvements towards novel surgical techniques.

  1. FABRICATION OF DIAMOND TUBES IN BIAS-ENHANCED HOT-FILAMENT CHEMICAL VAPOR DEPOSITION SYSTEM

    Institute of Scientific and Technical Information of China (English)

    CHEN Ming; MA Yuping; XIANG Daohui; SUN Fanghong

    2007-01-01

    Deposition of diamond thin films on tungsten wire Substrate with the gas mixture of acetone and hydrogen by using bias-enhanced hol filament chemical vapor deposition (CVD) with the tantalum wires being optimized arranged is investigated. The self-supported diamond tubes are obtained by etching away the tungsten Substrates. The quality of the diamond film before and after the removal of Substrates is observed by scanning electron microscope (SEM) and Raman spectrum. The results show that the cylindrical diamond tubes with good quality and uniform thickness are obtained on tungsten wires by using bias enhanced hot filament CVD. The compressive stress in diamond film formed during the deposition is released after the Substrate etches away by mixture of H202 and NH4OH. There is no residual stress in diamond tube after Substrate removal.

  2. Inclusions of Hydrocarbon Fluids in Diamonds From Wafangdian, Liaoning, China

    Science.gov (United States)

    Leung, I. S.; Tsao, C.

    2015-12-01

    We studied a large number of industrial-grade diamonds from Pipe 50 of Liaoning, China. These diamonds are not suitable for polishing into gems or making cutting tools. They are usually crushed to form abrasives, without much scientific scrutiny. We report here fluid inclusions in dozens of diamonds. The first type of fluids occur in the outer rim of diamonds, just below the surface, while their interior is free of visible fluids. Under UV radiation, when a non-fluorescent diamond appeared dim, bubbles of included fluids became visible as yellow and blue spherules. Such diamonds are sometimes encrusted with euhedral micro-diamonds resembling those on thin films grown by CVD. The second type of fluid-rich diamonds display iridescence of pink, blue, green and yellow colors. They show lamellar, filamentous, or tubular structures, some of the tubes are filled with granules, probably grown from fluids in the tubes. An FT-IR investigation of both types yielded similar results. Apart from absorption due to intrinsic diamond lattice vibrations, we found an outstanding group of bands just below wavenumber 3000. This indicates the presence of a saturated aliphatic hydrocarbons of long chain length. Our results seem to implicate that hydrocarbons might be an important component in Earth's mantle, which might even have provided carbon from which diamonds crystllized.

  3. Diamond-based 1-D imaging arrays

    Energy Technology Data Exchange (ETDEWEB)

    Lansley, S.P.; Williams, O.A.; Ye, H. [Electronic and Electrical Engineering, University College London, Torrington Place, London WC1E 7JE (United Kingdom); Rizvi, N.; Whitfield, M.D.; Jackman, R.B. [Exitech Limited, Hanborough Park, Long Hanborough, Oxford OX8 8LH (United Kingdom); McKeag, R.D. [Centronic Ltd., Centronic House, King Henry' s Drive, New Addington, Croydon CR9 OBG (United Kingdom)

    2002-10-16

    Diamond has shown great promise for the fabrication of high sensitivity, low dark current, fast and visible-blind deep UV photodetectors. In addition to careful choice of substrate material, defect passivation treatments applied to the diamond after growth have been found to considerably enhance the detector characteristics achieved. In this paper we report on the first purposefully designed 1-D CVD diamond imaging array for the detection of nanosecond 193 nm excimer laser pulses using this approach. It is shown to perform extremely well, giving less than 2% pixel-to-pixel variation in signal response, and is fast enough to avoid any sign of charge build up during prolonged operation. (Abstract Copyright [2002], Wiley Periodicals, Inc.)

  4. Electronic structure studies of nanocrystalline diamond grain boundaries

    Energy Technology Data Exchange (ETDEWEB)

    Zapol, P.; Sternberg, M.; Frauenheim, T.; Gruen, D. M.; Curtiss, L. A.

    1999-11-29

    Diamond growth from hydrogen-poor plasmas results in diamond structures that are profoundly different from conventionally CVD-grown diamond. High concentration of carbon dimers in the microwave plasma results in a high rate of heterogeneous renucleation leading to formation of nanocrystalline diamond with a typical grain size of 3--10 nm. Therefore, up to 10% of carbon atoms are located in the grain boundaries. In this paper the authors report on density-functional based tight-binding molecular dynamics calculations of the structure of a {Sigma}13 twist (100) grain boundary in diamond. Beginning with a coincidence site lattice model, simulated annealing of the initial structure was performed at 1,500 K followed by relaxation toward lower temperatures. About one-half of the carbons in the grain boundary are found to be three-coordinated. Coordination numbers, bond length and bond angle distributions are analyzed and compared to those obtained in previous studies.

  5. Initial damage processes for diamond film exposure to hydrogen plasma

    Energy Technology Data Exchange (ETDEWEB)

    Deslandes, A., E-mail: acd@ansto.gov.au [Institute for Environmental Research, Australian Nuclear Science and Technology Organisation, Sydney (Australia); Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Sydney (Australia); Guenette, M.C. [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Sydney (Australia); Samuell, C.M. [Plasma Research Laboratory, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia); Karatchevtseva, I. [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Sydney (Australia); Ionescu, M.; Cohen, D.D. [Institute for Environmental Research, Australian Nuclear Science and Technology Organisation, Sydney (Australia); Blackwell, B. [Plasma Research Laboratory, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia); Corr, C., E-mail: cormac.corr@anu.edu.au [Plasma Research Laboratory, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia); Riley, D.P., E-mail: dry@ansto.gov.au [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Sydney (Australia)

    2013-12-15

    Graphical abstract: -- Highlights: • Exposing chemical vapour deposited (CVD) diamond films in a recently constructed device, MAGPIE, specially commissioned to simulate fusion plasma conditions. • Non-diamond material is etched from the diamond. • There is no hydrogen retention observed, which suggests diamond is an excellent candidate for plasma facing materials. • Final structure of the surface is dependent on synergistic effects of etching and ion-induced structural change. -- Abstract: Diamond is considered to be a possible alternative to other carbon based materials as a plasma facing material in nuclear fusion devices due to its high thermal conductivity and resistance to chemical erosion. In this work CVD diamond films were exposed to hydrogen plasma in the MAGnetized Plasma Interaction Experiment (MAGPIE): a linear plasma device at the Australian National University which simulates plasma conditions relevant to nuclear fusion. Various negative sample stage biases of magnitude less than 500 V were applied to control the energies of impinging ions. Characterisation results from SEM, Raman spectroscopy and ERDA are presented. No measureable quantity of hydrogen retention was observed, this is either due to no incorporation of hydrogen into the diamond structure or due to initial incorporation as a hydrocarbon followed by subsequent etching back into the plasma. A model is presented for the initial stages of diamond erosion in fusion relevant hydrogen plasma that involves chemical erosion of non-diamond material from the surface by hydrogen radicals and damage to the subsurface region from energetic hydrogen ions. These results show that the initial damage processes in this plasma regime are comparable to previous studies of the fundamental processes as reported for less extreme plasma such as in the development of diamond films.

  6. Spectroscopic properties and radiation damage investigation of a diamond based Schottky diode for ion-beam therapy microdosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Verona, C.; Marinelli, Marco; Verona-Rinati, G. [INFN - Dipartimento di Ingegneria Industriale, Università di Roma “Tor Vergata,” Roma (Italy); Magrin, G.; Solevi, P.; Mayer, R. [EBG MedAustron Marie Curie-St. 5, 2700 Wiener Neustadt (Austria); Grilj, V.; Jakšić, M. [Ruder Boškovic Institute, Bijenicka cesta 54, P.O. Box 180, 10002 Zagreb (Croatia)

    2015-11-14

    In this work, a detailed analysis of the properties of a novel microdosimeter based on a synthetic single crystal diamond is reported. Focused ion microbeams were used to investigate the device spectropscopic properties as well as the induced radiation damage effects. A diamond based Schottky diode was fabricated by chemical vapor deposition with a very thin detecting region, about 400 nm thick (approximately 1.4 μm water equivalent thickness), corresponding to the typical size in microdosimetric measurements. A 200 × 200 μm{sup 2} square metallic contact was patterned on the diamond surface by standard photolithography to define the sensitive area. Experimental measurements were carried out at the Ruder Boškovic′ Institute microbeam facility using 4 MeV carbon and 5 MeV silicon ions. Ion beam induced charge maps were employed to characterize the microdosimeter response in terms of its charge collection properties. A stable response with no evidence of polarization or memory effects was observed up to the maximum investigated ion beam flux of about 1.7 × 10{sup 9} ions·cm{sup −2}·s{sup −1}. A homogeneity of the response about 6% was found over the sensitive region with a well-defined confinement of the response within the active area. Tests of the radiation damage effect were performed by selectively irradiating small areas of the device with different ion fluences, up to about 10{sup 12} ions/cm{sup 2}. An exponential decrease of the charge collection efficiency was observed with a characteristic decay constant of about 4.8 MGy and 1 MGy for C and Si ions, respectively. The experimental data were analyzed by means of GEANT4 Monte Carlo simulations. A direct correlation between the diamond damaging effect and the Non Ionizing Energy Loss (NIEL) fraction was found. In particular, an exponential decay of the charge collection efficiency with an exponential decay as a function of NIEL is observed, with a characteristic constant of about

  7. Mosaic diamond based detector for MIPs detection, T0 determination and triggering in HADES

    Energy Technology Data Exchange (ETDEWEB)

    Pietraszko, Jerzy; Koenig, Wolfgang [GSI Helmholtzzentum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Collaboration: HADES-Collaboration

    2015-07-01

    The CVD based diamond detectors were successfully used for HI detection in HADES already in 2001. In the following experiments the polycrystalline diamond material showed very good performance (time resolution below 50 ps sigma) and stable long term operation. Detection of the minimum ionising particles (MIPs) by means of the diamond detectors is a challenging task mainly because of very small energy deposit in the diamond material. In this case the single crystalline CVD diamond material has to be used which is well known for its excellent charge collection efficiency (almost 100 %) and for its very good timing properties. For pion induced experiments at HADES a large area, segmented, position sensitive, operated in vacuum detector was developed. The construction of the detector is presented along with the requirements and the obtained performance.

  8. Adhesion analysis of polycrystalline diamond films on molybdenum by means of scratch, indentation and sand abrasion testing

    NARCIS (Netherlands)

    Buijnsters, J.G.; Shankar, P.; Enckevort, W.J.P. van; Schermer, J.J.; Meulen, J.J. ter

    2005-01-01

    Diamond films have been grown by hot-filament chemical vapour deposition (CVD) on molybdenum substrates under different growth conditions. The films grown with increasing substrate temperatures show a higher interconnection of diamond grains, whereas increasing methane concentrations in the 0.5-4.0%

  9. Adhesion analysis of polycrystalline diamond films on molybdenum by means of scratch, indentation and sand abrasion testing

    NARCIS (Netherlands)

    Buijnsters, J.G.; Shankar, P.; Enckevort, W.J.P. van; Schermer, J.J.; Meulen, J.J. ter

    2005-01-01

    Diamond films have been grown by hot-filament chemical vapour deposition (CVD) on molybdenum substrates under different growth conditions. The films grown with increasing substrate temperatures show a higher interconnection of diamond grains, whereas increasing methane concentrations in the 0.5-4.0%

  10. Properties of Diamond Film/Alumina Composites for Integrated Circuits with Ultra-High Speed and High Power

    Institute of Scientific and Technical Information of China (English)

    WANG Lin-Jun; XIA Yi-Ben; FANG Zhi-Jun; ZHANG Ming-Long; SHEN Hu-Jiang

    2004-01-01

    @@ We report the properties of the diamond film/alumina composites which were thought of as promising substrate materials for integrated circuits with ultra-high speed and high power. The measurement results of dielectric properties of diamond film/alumina composites show that the coating of CVD diamond films could effectively reduce the dielectric constant of the composite. Carbon ion implantation into alumina substrates prior to the diamond deposition can reduce the dielectric loss of the composite from 5 × 10-3 to 2 × 10-3, and can give the composite better frequency stability. The thermal conductivity of composites could be obviously increased by coating CVD diamond film. The composite has a dielectric constant of 6.5 and a thermal conductivity of 3.98 W/(cmK) when the thickness of diamond film is up to 100 μm.

  11. Nanocrystalline sp 2 and sp 3 carbons: CVD synthesis and applications

    Science.gov (United States)

    Terranova, M. L.; Rossi, M.; Tamburri, E.

    2016-11-01

    The design and production of innovative materials based on nanocrystalline sp 2- and sp 3-coordinated carbons is presently a focus of the scientific community. We present a review of the nanostructures obtained in our labs using a series of synthetic routes, which make use of chemical vapor deposition (CVD) techniques for the selective production of non-planar graphitic nanostructures, nanocrystalline diamonds, and hybrid two-phase nanostructures.

  12. Chemical Analysis of Impurity Boron Atoms in Diamond Using Soft X-ray Emission Spectroscopy

    OpenAIRE

    Muramatsu, Yasuji

    2009-01-01

    To analyze the local structure and/or chemical states of boron atoms in boron-doped diamond, which can be synthesized by the microwave plasma-assisted chemical vapor deposition method (CVD-B-diamond) and the temperature gradient method at high pressure and high temperature (HPT-B-diamond), we measured the soft X-ray emission spectra in the CK and BK regions of B-diamonds using synchrotron radiation at the Advanced Light Source (ALS). X-ray spectral analyses using the fingerprint method and mo...

  13. Progress on Diamond-Based Cylindrical Dielectric Accelerating Structures

    Science.gov (United States)

    Kanareykin, A.; Schoessow, P.; Conde, M.; Gai, W.

    2006-11-01

    The development of a high gradient diamond-based cylindrical dielectric loaded accelerator (DLA) is presented. A diamond-loaded DLA can potentially sustain accelerating gradients far in excess of the limits experimentally observed for conventional metallic accelerating structures. The electrical and mechanical properties of diamond make it an ideal candidate material for use in dielectric accelerators: high rf breakdown level, extremely low dielectric losses and the highest available thermoconductive coefficient. We used the hot-filament Chemical Vapor Deposition (CVD) process to produce high quality 5-10 cm long cylindrical diamond layers. Our collaboration has also been developing a new method of CVD diamond surface preparation that reduces the secondary electron emission coefficient below unity. Special attention was paid to the numerical optimization of the waveguide to structure rf coupling section, where the surface magnetic and electric fields were minimized relative to the accelerating gradient and within known metal surface breakdown limits. We conclude with a brief overview of the use of diamond microstructures for use in compact rf sources.

  14. Diamond dosimetry: Outcomes of the CANDIDO and CONRAD INFN projects

    Energy Technology Data Exchange (ETDEWEB)

    Bucciolini, M. [Dipartimento di Fisiopatologia dell' Universita and INFN, Florence (Italy)]. E-mail: marta@dfc.unifi.it; Borchi, E. [Dipartimento di Energetica dell' Universita and INFN, Florence (Italy); Bruzzi, M. [Dipartimento di Energetica dell' Universita and INFN, Florence (Italy); Casati, M. [Dipartimento di Fisiopatologia dell' Universita and INFN, Florence (Italy); Cirrone, P. [Laboratori Nazionali del SUD, INFN, Catania (Italy); Cuttone, G. [Laboratori Nazionali del SUD, INFN, Catania (Italy); De Angelis, C. [Dipartimento di Tecnologie e Salute, Istituto Superiore di Sanita and INFN, Rome (Italy); Lovik, I. [Dipartimento di Fisiopatologia dell' Universita and INFN, Florence (Italy); Onori, S. [Dipartimento di Tecnologie e Salute, Istituto Superiore di Sanita and INFN, Rome (Italy); Raffaele, L. [Laboratori Nazionali del SUD, INFN, Catania (Italy); Sciortino, S. [Dipartimento di Energetica dell' Universita and INFN, Florence (Italy)

    2005-10-21

    This paper reviews the main results of the study, carried out in the framework of the Italian National Institute of Nuclear Physics (INFN, Istituto Nazionale di Fisica Nucleare) projects, namely CANDIDO and CONRAD, on natural and synthetic diamond-based dosimeters for clinical radiotherapy. Characteristics of diamond such as radiation hardness, high sensitivity, tissue equivalence, etc., make this material interesting for dosimetry applications. For some years, natural diamonds have been commercially available for on-line radiotherapy dosimetry. Nevertheless, recent developments in the 'Chemical Vapour Deposition' (CVD) technique have addressed the attention on synthetic samples that potentially could be grown at low cost and with features suitable for dosimetric use. Several samples, differently grown and with different electrical contacts, have been compared by measuring their current response during irradiation with high-energy photon, electron and proton beams. Properties of dosimetric interest such as linearity, pre-irradiation dose, dose rate dependence, stability and rise time have been investigated. The results obtained so far within the INFN collaboration demonstrate the suitability of natural diamond detectors for many radiotherapy applications and the great potential of CVD diamond-based devices even though, at present, the commercial natural diamond dosimeters have a better behaviour with respect to the synthetic samples. Further efforts have to be made mainly to improve the dynamic of response and performance stability.

  15. Diamond dosimetry: Outcomes of the CANDIDO and CONRAD INFN projects

    Science.gov (United States)

    Bucciolini, M.; Borchi, E.; Bruzzi, M.; Casati, M.; Cirrone, P.; Cuttone, G.; De Angelis, C.; Lovik, I.; Onori, S.; Raffaele, L.; Sciortino, S.

    2005-10-01

    This paper reviews the main results of the study, carried out in the framework of the Italian National Institute of Nuclear Physics (INFN, Istituto Nazionale di Fisica Nucleare) projects, namely CANDIDO and CONRAD, on natural and synthetic diamond-based dosimeters for clinical radiotherapy. Characteristics of diamond such as radiation hardness, high sensitivity, tissue equivalence, etc., make this material interesting for dosimetry applications. For some years, natural diamonds have been commercially available for on-line radiotherapy dosimetry. Nevertheless, recent developments in the "Chemical Vapour Deposition" (CVD) technique have addressed the attention on synthetic samples that potentially could be grown at low cost and with features suitable for dosimetric use. Several samples, differently grown and with different electrical contacts, have been compared by measuring their current response during irradiation with high-energy photon, electron and proton beams. Properties of dosimetric interest such as linearity, pre-irradiation dose, dose rate dependence, stability and rise time have been investigated. The results obtained so far within the INFN collaboration demonstrate the suitability of natural diamond detectors for many radiotherapy applications and the great potential of CVD diamond-based devices even though, at present, the commercial natural diamond dosimeters have a better behaviour with respect to the synthetic samples. Further efforts have to be made mainly to improve the dynamic of response and performance stability.

  16. Graded composite diamond coatings with top-layer nanocrystallinity and interfacial integrity: Cross-sectional Raman mapping

    Energy Technology Data Exchange (ETDEWEB)

    Dumpala, Ravikumar [Manufacturing Engineering Section, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036 (India); Nano Functional Materials Technology Centre, Department of Physics, Indian Institute of Technology Madras, Chennai 600036 (India); Ramamoorthy, B. [Manufacturing Engineering Section, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036 (India); Rao, M.S. Ramachandra, E-mail: msrrao@iitm.ac.in [Nano Functional Materials Technology Centre, Department of Physics, Indian Institute of Technology Madras, Chennai 600036 (India)

    2014-01-15

    Cross-sectional structural characteristics of the CVD diamond coatings deposited on the tungsten carbide (WC-Co) substrates were analysed using Raman imaging technique. The grain size of the nanocrystalline diamond (NCD) coatings was observed to deviate from the nanocrystallinity with increasing thickness and exhibited the surface characteristics of microcrystalline diamond (MCD). However, thick diamond coatings with surface nanocrystallinity is the key requirement for load-bearing tribological applications. Tribological tests have clearly indicated the significance and need for the top-layer nanocrystallinity. Graded composite diamond coatings with an architecture of NCD/transition-layer/MCD/WC-Co are potentail candiadates to realize thick diamond coatings with top-layer nanocrystallinity. Residual stresses along the cross-section of the graded composite diamond coatings were analysed using Raman imaging technique, which confirmed the improved interfacial integrity of the graded composite diamond coatings.

  17. First result on biased CMOS MAPs-on-diamond devices

    Energy Technology Data Exchange (ETDEWEB)

    Kanxheri, K., E-mail: keida.kanxheri@pg.infn.it [Università degli Studi di Perugia, Perugia (Italy); INFN Perugia, Perugia (Italy); Citroni, M.; Fanetti, S. [LENS Firenze, Florence (Italy); Lagomarsino, S. [Università degli Studi di Firenze, Florence (Italy); INFN Firenze, Pisa (Italy); Morozzi, A. [Università degli Studi di Perugia, Perugia (Italy); INFN Perugia, Perugia (Italy); Parrini, G. [Università degli Studi di Firenze, Florence (Italy); Passeri, D. [Università degli Studi di Perugia, Perugia (Italy); INFN Perugia, Perugia (Italy); Sciortino, S. [Università degli Studi di Firenze, Florence (Italy); INFN Firenze, Pisa (Italy); Servoli, L. [INFN Perugia, Perugia (Italy)

    2015-10-01

    Recently a new type of device, the MAPS-on-diamond, obtained bonding a thinned to 25 μm CMOS Monolithic Active Pixel Sensor to a standard 500 μm pCVD diamond substrate, has been proposed and fabricated, allowing a highly segmented readout (10×10 μm pixel size) of the signal produced in the diamond substrate. The bonding between the two materials has been obtained using a new laser technique to deliver the needed energy at the interface. A biasing scheme has been adopted to polarize the diamond substrate to allow the charge transport inside the diamond without disrupting the functionalities of the CMOS Monolithic Active Pixel Sensor. The main concept of this class of devices is the capability of the charges generated in the diamond by ionizing radiation to cross the silicon–diamond interface and to be collected by the MAPS photodiodes. In this work we demonstrate that such passage occurs and measure its overall efficiency. This study has been carried out first calibrating the CMOS MAPS with monochromatic X-rays, and then testing the device with charged particles (electrons) either with and without biasing the diamond substrate, to compare the amount of signal collected.

  18. Analyzing the performance of diamond-coated micro end mills.

    Energy Technology Data Exchange (ETDEWEB)

    Torres, C. D.; Heaney, P. J.; Sumant, A. V.; Hamilton, M. A.; Carpick, R. W.; Pfefferkorn, F. E.; Univ. of Wisconsin at Madison; Univ. of Pennsylvania

    2009-06-01

    A method is presented to improve the tool life and cutting performance of 300 {micro}m diameter tungsten carbide (WC) micro end mills by applying thin (<300 nm) fine-grained diamond (FGD) and nanocrystalline diamond (NCD) coatings using the hot-filament chemical vapor deposition (HF-CVD) process. The performance of the diamond-coated tools has been evaluated by comparing their performance in dry slot milling of 6061-T6 aluminum against uncoated WC micro end mills. Tool wear, coating integrity, and chip morphology were characterized using SEM and white light interferometry. The initial test results show a dramatic improvement in the tool integrity (i.e., corners not breaking off), a lower wear rate, no observable adhesion of aluminum to the diamond-coated tool, and a significant reduction in the cutting forces (>50%). Reduction of the cutting forces is attributed to the low friction and adhesion of the diamond coating. However, approximately 80% of the tools coated with the larger FGD coatings failed during testing due to delamination. Additional machining benefits were attained for the NCD films, which was obtained by using a higher nucleation density seeding process for diamond growth. This process allowed for thinner, smaller grained diamond coatings to be deposited on the micro end mills, and enabled continued operation of the tool even after the integrity of the diamond coating had been compromised. As opposed to the FGD-coated end mills, only 40% of the NCD-tools experienced delamination issues.

  19. Development of diamond coated tool and its performance in machining Al–11%Si alloy

    Indian Academy of Sciences (India)

    B Sahoo; A K Chattopadhyay; A B Chattopadhyay

    2002-11-01

    An attempt has been made to deposit CVD diamond coating on conventional carbide tool using hot filament CVD process. ISO grade K10 turning inserts with SPGN 120308 geometry were used to deposit diamond coating. This diamond coating well covering the rake surface, cutting edges and flank surfaces could be successfully deposited. The coatings were characterized by SEM, XRD and Raman spectroscopy for coating quality, morphology etc. Performance of diamond coated tool relative to that of uncoated carbide tool was evaluated in turning Al–11%Si alloy under dry environment. The diamond coated tool outperformed the uncoated carbide tool which severely suffered from sizeable built-up edge formation leading not only to escalation of cutting forces but also poorer surface finish. In contrast, the diamond coated tool, owing to chemical inertness of diamond coating towards the work material, did not show any trace of edge built-up even in dry environment and could maintain low level of cutting forces and remarkably improved surface finish. It has been further revealed that success of the diamond coated tool depends primarily on adhesion of the diamond coating with the carbide substrate and this is strongly influenced by the pre-treatment of the carbide substrate surface before coating.

  20. Diamond Deposition on WC/Co Alloy with a Molybdenum Intermediate Layer

    Science.gov (United States)

    Liu, Sha; Yu, Zhi-Ming; Yi, Dan-Qing

    It is known that in the condition of chemical vapor deposition (CVD) diamond process, molybdenum is capable of forming carbide known as the "glue" which promotes growth of the CVD diamond, and aids its adhesion by (partial) relief of stresses at the interface. Furthermore, the WC grains are reaction bonded to the Mo2C phase. Therefore, molybdenum is a good candidate material for the intermediate layer between WC-Co substrates and diamond coatings. A molybdenum intermediate layer of 1-3 μm thickness was magnetron sputter-deposited on WC/Co alloy prior to the deposition of diamond coatings. Diamond films were deposited by hot filament chemical vapor deposition (HFCVD). The chemical quality, morphology, and crystal structure of the molybdenum intermediate layer and the diamond coatings were characterized by means of SEM, EDX, XRD and Raman spectroscopy. It was found that the continuous Mo intermediate layer emerged in spherical shapes and had grain sizes of 0.5-1.5 μm after 30 min sputter deposition. The diamond grain growth rate was slightly slower as compared with that of uncoated Mo layer on the WC-Co substrate. The morphologies of the diamond films on the WC-Co substrate varied with the amount of Mo and Co on the substrate. The Mo intermediate layer was effective to act as a buffer layer for both Co diffusion and diamond growth.

  1. Time Dependent DD Neutrons Measurement Using a Single Crystal Chemical Vapor Deposition Diamond Detector on EAST

    Science.gov (United States)

    Du, Tengfei; Peng, Xingyu; Chen, Zhongjing; Hu, Zhimeng; Ge, Lijian; Hu, Liqun; Zhong, Guoqiang; Pu, Neng; Chen, Jinxiang; Fan, Tieshuan

    2016-09-01

    A single crystal chemical vapor deposition (scCVD) diamond detector has been successfully employed for neutron measurements in the EAST (Experimental Advanced Superconducting Tokamak) plasmas. The scCVD diamond detector coated with a 5 μm 6LiF (95% 6Li enriched) layer was placed inside a polyethylene moderator to enhance the detection efficiency. The time-dependent neutron emission from deuteron plasmas during neutral beam injection (NBI) heating was obtained. The measured results are compared with that of fission chamber detectors, which always act as standard neutron flux monitors. The scCVD diamond detector exhibits good reliability, stability and the capability to withstand harsh radiation environments despite its low detection efficiency due to the small active volume. supported by the National Magnetic Confinement Fusion Science Program of China (Nos. 2013GB106004 and 2012GB101003) and National Natural Science Foundation of China (No. 91226102)

  2. Simultaneous synthesis of nanodiamonds and graphene via plasma enhanced chemical vapor deposition (MW PE-CVD) on copper.

    Science.gov (United States)

    Gottlieb, Steven; Wöhrl, Nicolas; Schulz, Stephan; Buck, Volker

    2016-01-01

    The simultaneous growth of both nanodiamonds and graphene on copper samples is described for the first time. A PE-CVD process is used to synthesize graphene layers and nanodiamond clusters from a hydrogen/methane gas mixture as it is typically done successfully in thermal CVD processes for graphene synthesis. However, the standard thermal CVD process is not without problems since the deposition of graphene is affected by the evaporation of a notable amount of copper caused by the slow temperature increase typical for thermal CVD resulting in a long process time. In sharp contrast, the synthesis of graphene by PE-CVD can circumvent this problem by substantially shortening the process time at holding out the prospect of a lower substrate temperature. The reduced thermal load and the possibility to industrially scale-up the PE-CVD process makes it a very attractive alternative to the thermal CVD process with respect to the graphene production in the future. Nanodiamonds are synthesized in PE-CVD reactors for a long time because these processes offer a high degree of control over the film's nanostructure and simultaneously providing a significant high deposition rate. To model the co-deposition process, the three relevant macroscopic parameters (pressure, gas mixture and microwave power) are correlated with three relevant process properties (plasma ball size, substrate temperature and C2/Hα-ratio) and the influence on the quality of the deposited carbon allotropes is investigated. For the evaluation of the graphene as well as the nanodiamond quality, Raman spectroscopy used whereas the plasma properties are measured by optical methods. It is found that the diamond nucleation can be influenced by the C2/Hα-ratio in the plasma, while the graphene quality remains mostly unchanged by this parameter. Moreover it is derived from the experimental data that the direct plasma contact with the copper surface is beneficial for the nucleation of the diamond while the growth and

  3. Diamonds in meteorites – Raman mapping and cathodoluminescence studies

    Directory of Open Access Journals (Sweden)

    A.T. Karczemska

    2010-11-01

    Full Text Available diversity among the diversity of other extraterrestrial carbon phases. The main subject of research shown here are example meteorites consisting diamonds: ureilites DaG 868 and Dho 3013. Results are compared with previous investigations. Diamonds exist in many different meteorites, interplanetary dust particles (IDPs and in comets dust. Origin of different diamonds is still debated among the scientists, two main possibilities are taken into consideration CVD process or shock metamorphism. Understanding laboratory techniques of manufacturing diamond helps in understanding the processes taking place in the Space. From the other side, the new findings and discoveries give the new insight to material science and laboratory techniques.Design/methodology/approach: The samples were examined with different methods, the most investigations presented here are Raman Mapping and Cathodoluminescence (CL.Findings: Diamonds have been found in different samples with different shock stages. It means that not all diamonds in urelites could have shock origin. Diamonds from examined samples show high diversity, they exist in different sizes, from nanodiamonds to micrometer sizes diamonds and in different polytypes. Shifts of Raman diamond peaks indicates this.Research limitations/implications: Results show the possibilities of creating the new diamond-based materials similar to those found in meteorites. Diamond polytypes are not well characterized yet and could give some surprises for materials science. For future research it would be interesting to apply more methods such as X-ray diffraction or HRTEM.Originality/value: SEM+BSE+EDS+CL results and Raman imaging results of DaG 868 and Dho 1303 ureilites are shown for the first time.

  4. The potential use of diamond coated tungsten tips as a field ionisation source

    Energy Technology Data Exchange (ETDEWEB)

    Brown, A.; Prawer, S.; Legge, G.J.F.; Kostidis, L.I. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1996-12-31

    Tungsten tips are convenient for use in a high brightness gaseous phase field ionisation source. However, the lifetime of these tips is not adequate for practical use. The authors are investigating whether coating tungsten tips with diamond using Chemical Vapor Deposition (CVD) will improve the practicality of using these tips by an improvement in longevity of the source and/or an improvement in brightness due to the effects of the property of negative electron affinity which has been observed on CVD diamond. 1 ref.

  5. Growth of Free-standing Diamond Films on Graphite Substrates with Ti Interlayers

    Institute of Scientific and Technical Information of China (English)

    LI Hui-qing; LI Cheng-ming; CHEN Guang-chao; LU Fan-xiu; TANG Wei-zhong; TONG Yu-mei

    2004-01-01

    Free-standing diamond films, deposited using Dc Arc Plasma Jet CVD method onto graphite substrates with titanium interlayers, have been investigated. The Ti interlayers were deposited by arc ion plating equipments. The thickness,morphology and composite phase of Ti interlayers were examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The titanium carbide (TiC) was detected in both sides of the interlayers, which played an important role with respect to reasonable adhesion with film and diamond nucleation. The semi-translucent diamond films were characterized by SEM and Raman spectrum. The sharp diamond peak with low intensity of amorphous carbon shows that diamond films have very high quality. The overall results suggest that plating Ti interlayer on graphite substrate is an effective way to obtain optical grade free-standing diamond films.

  6. Growth of Free-standing Diamond Films on Graphite Substrates with Ti Interlayers

    Institute of Scientific and Technical Information of China (English)

    LIHui-qing; LICheng-ming; CHENGuang-chao; LUFan-xiu; TANGWei-zhong; TONGYu-mei

    2004-01-01

    Free-standing diamond films, deposited using De Arc Plasma Jet CVD method onto graphite substrates with titanium interlayers, have been investigated. The Ti interlayers were deposited by arc ion plating equipments. The thickness, morphology and composite phase of Ti interlayers were examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The titanium carbide (TIC) was detected in both sides of the interlayers, which played an important role with respect to reasonable adhesion with film and diamond nucleation. The semi-translucent diamond films were characterized by SEM and Raman spectrum. The sharp diamond peak with low intensity of amorphous carbon shows that diamond films have very high quality. The overall results suggest that plating Ti interlayer on graphite substrate is an effective way to obtain optical grade free-standing diamond films.

  7. The use of thin diamond films in fiber-optic low-coherence interferometers

    Science.gov (United States)

    Milewska, D.; Karpienko, K.

    2016-01-01

    In this paper we present the use of thin diamond films in fiber-optic low-coherence interferometers. Two kinds of diamond surfaces were used: undoped diamond film and boron- doped diamond film. They were deposited on glass plates as well as silicon layers. A conventionally used mirror was used as a reference layer. Diamond films were deposited using Microwave Plasma Enhanced Chemical Vapour Deposition (μPE CVD) system. Measurements were performed using two superluminescent diodes (SLD) with wavelengths of 1300 mm and 1550 mm. The optimal conditions for each layers were examined: the required wavelength of the light source and the length of Fabry-Perot interferometer cavity. Metrological parameters of Fabry-Perot interferometer with different mirrors were compared. The presented thin diamond films may be an interesting alternative to the commonly used reflective surfaces.

  8. Preparation of diamond/Cu microchannel heat sink by chemical vapor deposition

    Institute of Scientific and Technical Information of China (English)

    刘学璋; 罗浩; 苏栩; 余志明

    2015-01-01

    A Ti interlayer with thickness about 300 nm was sputtered on Cu microchannels, followed by an ultrasonic seeding with nanodiamond powders. Adherent diamond film with crystalline grains close to thermal equilibrium shape was tightly deposited by hot-filament chemical vapor deposition (HF-CVD). The nucleation and growth of diamond were investigated with micro-Raman spectroscope and field emission scanning electron microscope (FE-SEM) with energy dispersive X-ray detector (EDX). Results show that the nucleation density is found to be up to 1010 cm−2. The enhancement of the nucleation kinetics can be attributed to the nanometer rough Ti interlayer surface. An improved absorption of nanodiamond particles is found, which act as starting points for the diamond nucleation during HF-CVD process. Furthermore, finite element simulation was conducted to understand the thermal management properties of prepared diamond/Cu microchannel heat sink.

  9. Maskless Selective Growth Method for p-n Junction Applications on (001)-Oriented Diamond

    Science.gov (United States)

    Kato, Hiromitsu; Makino, Toshiharu; Ogura, Masahiko; Takeuchi, Daisuke; Yamasaki, Satoshi

    2012-09-01

    A maskless selective growth method by chemical vapor deposition (CVD) is a promising technique for fabricating various types of p-n junction devices on diamond semiconductors, instead of the impurity doping by ion-implantation technique. We control diamond growth and impurity doping using patterned surface morphologies of (001)-oriented diamond, which results in a selective growth along the or direction. In the case of phosphorus doping, the diamond with selective growth shows the n-type conducting property, whereas that with selective growth shows the insulating property owing to the coincorporation of hydrogen. Such strong orientational properties are peculiar in CVD phosphorus doping. The detailed procedures of this selective growth method and the electrical properties of fabricated vertical and lateral p-n junction diodes are described in this article.

  10. Review: Plasma-enhanced chemical vapor deposition of nanocrystalline diamond

    Directory of Open Access Journals (Sweden)

    Katsuyuki Okada

    2007-01-01

    Full Text Available Nanocrystalline diamond films have attracted considerable attention because they have a low coefficient of friction and a low electron emission threshold voltage. In this paper, the author reviews the plasma-enhanced chemical vapor deposition (PE-CVD of nanocrystalline diamond and mainly focuses on the growth of nanocrystalline diamond by low-pressure PE-CVD. Nanocrystalline diamond particles of 200–700 nm diameter have been prepared in a 13.56 MHz low-pressure inductively coupled CH4/CO/H2 plasma. The bonding state of carbon atoms was investigated by ultraviolet-excited Raman spectroscopy. Electron energy loss spectroscopy identified sp2-bonded carbons around the 20–50 nm subgrains of nanocrystalline diamond particles. Plasma diagnostics using a Langmuir probe and the comparison with plasma simulation are also reviewed. The electron energy distribution functions are discussed by considering different inelastic interaction channels between electrons and heavy particles in a molecular CH4/H2 plasma.

  11. Ionization signals from diamond detectors in fast-neutron fields

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, C. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); CIVIDEC Instrumentation, Wien (Austria); Frais-Koelbl, H. [University of Applied Sciences, Wiener Neustadt (Austria); Griesmayer, E.; Kavrigin, P. [CIVIDEC Instrumentation, Wien (Austria); Vienna University of Technology, Wien (Austria)

    2016-09-15

    In this paper we introduce a novel analysis technique for measurements with single-crystal chemical vapor deposition (sCVD) diamond detectors in fast-neutron fields. This method exploits the unique electronic property of sCVD diamond sensors that the signal shape of the detector current is directly proportional to the initial ionization profile. In fast-neutron fields the diamond sensor acts simultaneously as target and sensor. The interaction of neutrons with the stable isotopes {sup 12}C and {sup 13}C is of interest for fast-neutron diagnostics. The measured signal shapes of detector current pulses are used to identify individual types of interactions in the diamond with the goal to select neutron-induced reactions in the diamond and to suppress neutron-induced background reactions as well as γ-background. The method is verified with experimental data from a measurement in a 14.3 MeV neutron beam at JRC-IRMM, Geel/Belgium, where the {sup 13}C(n, α){sup 10}Be reaction was successfully extracted from the dominating background of recoil protons and γ-rays and the energy resolution of the {sup 12}C(n, α){sup 9}Be reaction was substantially improved. The presented analysis technique is especially relevant for diagnostics in harsh radiation environments, like fission and fusion reactors. It allows to extract the neutron spectrum from the background, and is particularly applicable to neutron flux monitoring and neutron spectroscopy. (orig.)

  12. High collection efficiency thin film diamond particle detectors

    Energy Technology Data Exchange (ETDEWEB)

    Bergonzo, P.; Foulon, F.; Marshall, R.D.; Jany, C.; Brambilla, A. [CEA/Saclay, Gif-sur-Yvette (France); McKeag, R.D.; Jackman, R.B. [University College, London (United Kingdom)

    1998-12-31

    Diamond is a resilient material with rather extreme electronic properties. As such it is an interesting candidate for the fabrication of high performance solid state particle detectors. However, the commercially accessible form of diamond, grown by chemical vapor deposition (CVD) methods, is polycrystalline in nature and often displays rather poor electrical characteristics. This paper considers ways in which this material may be used to form alpha particle detectors with useful performance levels. One approach adopted has been to reduce the impurity levels within the feed-stock gases that are used to grow the diamond films. This has enabled significant improvements to be achieved in the mean carrier drift distance within the films leading to alpha detectors with up to 40% collection efficiencies. An alternative approach explored is the use of planar device geometries whereby charge collection is limited to the top surface of the diamond which comprises higher quality material than the bulk of the film. This has lead to collection efficiencies of 70%, the highest yet reported for polycrystalline CVD diamond based detectors. Techniques for improving the characteristics of these devices further are discussed.

  13. Ionization signals from diamond detectors in fast-neutron fields

    Science.gov (United States)

    Weiss, C.; Frais-Kölbl, H.; Griesmayer, E.; Kavrigin, P.

    2016-09-01

    In this paper we introduce a novel analysis technique for measurements with single-crystal chemical vapor deposition (sCVD) diamond detectors in fast-neutron fields. This method exploits the unique electronic property of sCVD diamond sensors that the signal shape of the detector current is directly proportional to the initial ionization profile. In fast-neutron fields the diamond sensor acts simultaneously as target and sensor. The interaction of neutrons with the stable isotopes 12 C and 13 C is of interest for fast-neutron diagnostics. The measured signal shapes of detector current pulses are used to identify individual types of interactions in the diamond with the goal to select neutron-induced reactions in the diamond and to suppress neutron-induced background reactions as well as γ-background. The method is verified with experimental data from a measurement in a 14.3 MeV neutron beam at JRC-IRMM, Geel/Belgium, where the 13C(n, α)10Be reaction was successfully extracted from the dominating background of recoil protons and γ-rays and the energy resolution of the 12C(n, α)9Be reaction was substantially improved. The presented analysis technique is especially relevant for diagnostics in harsh radiation environments, like fission and fusion reactors. It allows to extract the neutron spectrum from the background, and is particularly applicable to neutron flux monitoring and neutron spectroscopy.

  14. First use of single-crystal diamonds as fission-fragment detector

    Energy Technology Data Exchange (ETDEWEB)

    Frégeau, M.O.; Oberstedt, S.; Brys, T.; Gamboni, Th.; Geerts, W.; Hambsch, F.-J. [European Commission, DG Joint Research Centre (IRMM), B-2440 Geel (Belgium); Oberstedt, A. [OSSOLUTIONS Consulting, S-70353 Örebro (Sweden); Fundamental Physics, Chalmers University of Technology, S-41296 Göteborg (Sweden); Vidali, M. [European Commission, DG Joint Research Centre (IRMM), B-2440 Geel (Belgium)

    2015-08-11

    Single-crystal chemical vapor-deposited diamond (sCVD) was investigated for its ability to act as fission-fragment detector. In particular we investigated timing and energy resolution for application in a simultaneous time-of-flight and energy measurement to determine the mass of the detected fission fragment. Previous tests have shown that poly-crystalline chemical vapor deposited (pCVD) diamonds provide sufficient timing resolution, but their poor energy resolution did not allow complete separation between very low-energy fission fragments, α-particles and noise. Our present investigations prove artificial sCVD diamonds to show similar timing resolution as pCVD diamonds close to 100 ps. Improved pulse-height resolution allows the unequivocal separation of fission fragments, and the detection efficiency reaches 100%, but remains with about a few percent behind requirements for fragment-mass identification. With high-speed digital electronics a timing resolution well below 100 ps is possible. However, the strongly varying quality of the presently available diamond material does not allow application on a sufficiently large scale within reasonable investments.

  15. Chemical vapour deposited diamonds for dosimetry of radiotherapeutical beams

    Energy Technology Data Exchange (ETDEWEB)

    Bucciolini, M.; Mazzocchi, S. [Firenze Univ., Firenze (Italy). Dipartimento di Fisiopatologia Clinica; INFN, Firenze (Italy); Borchi, E.; Bruzzi, M.; Pini, S.; Sciortino, S. [Firenze Univ., Firenze (Italy). Dipartimento di Energetica; INFN, Firenze (Italy); Cirrone, G.A.P.; Guttone, G.; Raffaele, L.; Sabini, M.G. [INFN, Catania (Italy). Laboratori Nazionali del Sud

    2002-07-01

    This paper deals with the application of synthetic diamond detectors to the clinical dosimetry of photon and electron beams. It has been developed in the frame of INFN CANDIDO project and MURST Cofin. Diamonds grown with CVD (Chemical Vapour Deposition) technique have been studied; some of them are commercial samples while others have been locally synthesised. Experiments have been formed using both on-line and off-line approaches. For the off-line measurements, TL (thermoluminescent) and TSC (thermally stimulated current) techniques have been used.

  16. Fabrication of planarised conductively patterned diamond for bio-applications

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Wei [School of Physics, University of Melbourne, Parkville, Victoria (Australia); Fox, Kate, E-mail: kfox@unimelb.edu.au [School of Physics, University of Melbourne, Parkville, Victoria (Australia); Ganesan, Kumaravelu [School of Physics, University of Melbourne, Parkville, Victoria (Australia); Turnley, Ann M. [Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Victoria (Australia); Shimoni, Olga [School of Physics, University of Melbourne, Parkville, Victoria (Australia); Tran, Phong A. [Department of Chemical and Biomolecular Engineering, University of Melbourne, Parkville, Victoria (Australia); Lohrmann, Alexander; McFarlane, Thomas; Ahnood, Arman; Garrett, David J. [School of Physics, University of Melbourne, Parkville, Victoria (Australia); Meffin, Hamish [National Information and Communication Technology Australia, Victoria 3010 (Australia); Department of Electrical and Electronic Engineering, University of Melbourne, Victoria 3010 (Australia); O' Brien-Simpson, Neil M.; Reynolds, Eric C. [Oral Health Cooperative Research Centre, Melbourne Dental School, The University of Melbourne, 720 Swanston Street, Victoria 3010 (Australia); Prawer, Steven [School of Physics, University of Melbourne, Parkville, Victoria (Australia)

    2014-10-01

    The development of smooth, featureless surfaces for biomedical microelectronics is a challenging feat. Other than the traditional electronic materials like silicon, few microelectronic circuits can be produced with conductive features without compromising the surface topography and/or biocompatibility. Diamond is fast becoming a highly sought after biomaterial for electrical stimulation, however, its inherent surface roughness introduced by the growth process limits its applications in electronic circuitry. In this study, we introduce a fabrication method for developing conductive features in an insulating diamond substrate whilst maintaining a planar topography. Using a combination of microwave plasma enhanced chemical vapour deposition, inductively coupled plasma reactive ion etching, secondary diamond growth and silicon wet-etching, we have produced a patterned substrate in which the surface roughness at the interface between the conducting and insulating diamond is approximately 3 nm. We also show that the patterned smooth topography is capable of neuronal cell adhesion and growth whilst restricting bacterial adhesion. - Highlights: • We have fabricated a planar diamond device with conducting and insulating features. • A precise method is provided using CVD and RIE techniques to develop the substrate. • The step between conducting and insulating features is less than 3 nm. • Planar topography promotes neuronal cell adhesion and restricts bacterial adhesion. • Neuronal cells prefer conductive diamond (N-UNCD) to non-conductive diamond (UNCD)

  17. Efficient generation of nanoscale arrays of nitrogen-vacancy centers with long coherence time in diamond

    Science.gov (United States)

    Feng, Fupan; Wang, Junfeng; Zhang, Wenlong; Zhang, Jian; Lou, Liren; Zhu, Wei; Wang, Guanzhong

    2016-11-01

    Utilizing PMMA mask, nanoscale arrays of nitrogen-vacancy (NV) centers in diamond have been fabricated by ion beam implantation (IBM). Long coherence time of the spin of NV centers, comparable with that of the native NV centers in CVD grown diamond, has been achieved by high-temperature annealing. With dynamic decoupling technology, coherence time was extended to 1.4 millisecond, which enable an ac magnetic field detection with a sensitivity of 80 nT\\cdot Hz^{-1/2}.

  18. Using Si-doped diamond plate of sandwich type for spatial profiling of laser beam

    Science.gov (United States)

    Shershulin, V. A.; Samoylenko, S. R.; Sedov, V. S.; Kudryavtsev, O. S.; Ralchenko, V. G.; Nozhkina, A. V.; Vlasov, I. I.; Konov, V. I.

    2017-02-01

    We demonstrated a laser beam profiling method based on imaging of the laser induced photoluminescence of a transparent single-crystal diamond plate. The luminescence at 738 nm is caused by silicon-vacancy color centers formed in the epitaxial diamond film by its doping with Si during CVD growth of the film. The on-line beam monitor was tested for a cw laser emitting at 660 nm wavelength.

  19. AC Impedance Behaviour of Black Diamond Films

    Institute of Scientific and Technical Information of China (English)

    Haitao YE; Olivier GAUDIN; Richard B.JACKMAN

    2005-01-01

    The first measurement of impedance on free-standing diamond films from 0.1 Hz to 10 MHz up to 300℃ were reported. A wide range of chemical vapour deposition (CVD) materials were investigated, but here we concentrate are well fitted to a RC parallel circuit model and the equivalent resistance and capacitance for the diamond films have been estimated using the Zview curve fitting. The results show only one single semicircle response at each temperature measured. It was found that the resistance decreases from 62 MΩ at room temperature to 4 kΩ at300℃, with an activation energy around 0.51 eV. The equivalent capacitance is maintained at the level of 100 pF up to 300℃ suggesting that the diamond grain boundaries are dominating the conduction. At 400℃, the impedance at low frequencies shows a linear tail, which can be explained that the AC polarization of diamond/Au interface occurs.

  20. A multilayer innovative solution to improve the adhesion of nanocrystalline diamond coatings

    Energy Technology Data Exchange (ETDEWEB)

    Poulon-Quintin, A., E-mail: poulon@icmcb-bordeaux.cnrs.fr [CNRS, ICMCB, UPR 9048, F-33600 Pessac (France); Univ. Bordeaux, ICMCB, UPR 9048, F-33600 Pessac (France); Faure, C.; Teulé-Gay, L.; Manaud, J.P. [CNRS, ICMCB, UPR 9048, F-33600 Pessac (France); Univ. Bordeaux, ICMCB, UPR 9048, F-33600 Pessac (France)

    2015-03-15

    Highlights: • Improvement of the NCD adhesion on WC-12%Co substrates for tooling applications using a multi-interlayer additional system. • Reduction of the graphite layer thickness and continuity at the interface with the diamond. • Transmission electron microscopy study for a better understanding of the diffusion phenomena occurring at the interfaces. - Abstract: Nano-crystalline diamond (NCD) films grown under negative biased substrates by chemical vapor deposition (CVD) are widely used as surface overlay coating onto cermet WC-Co cutting tools to get better performances. To improve the diamond adhesion to the cermet substrate, suitable multi-layer systems have been added. They are composed of a cobalt diffusion barrier close to the substrate (single and sequenced nitrides layers) coated with a nucleation extra layer to improve the nucleus density of diamond during CVD processing. For all systems, before and after diamond deposition, transmission electron microscopy (TEM) has been performed for a better understanding of the diffusion phenomena occurring at the interfaces and to evaluate the presence of graphitic species at the interface with the diamond. Innovative multilayer system dedicated to the regulation of cobalt diffusion coated with a bilayer system optimized for the carbon diffusion control, is shown as an efficient solution to significantly reduce the graphite layer formation at the interface with the diamond down to 10 nm thick and to increase the adhesion of NCD diamond layer as scratch-tests confirm.

  1. Recent Advances in the Deposition of Diamond Coatings on Co-Cemented Tungsten Carbides

    Directory of Open Access Journals (Sweden)

    R. Polini

    2012-01-01

    Full Text Available Co-cemented tungsten carbides, namely, hard metals are largely used to manufacture high wear resistant components in several manufacturing segments. Coating hard metals with superhard materials like diamond is of utmost interest as it can further extend their useful lifespan. The deposition of diamond coatings onto WC-Co can be extremely complicated as a result of poor adhesion. This can be essentially ascribed to (i the mismatch in thermal expansion coefficients between diamond and WC-Co, at the typical high temperatures inside the chemical vapour deposition (CVD chamber, generates large residual stresses at the interface; (ii the role of surface Co inside the WC-Co matrix during diamond CVD, which promotes carbon dissolution and diffusion. The present investigation reviews the techniques by which Co-cemented tungsten carbides can be treated to make them prone to receive diamond coatings by CVD. Further, it proposes interesting ecofriendly and sustainable alternatives to further improve the diamond deposition process as well as the overall performance of the coated hard metals.

  2. Diamond electronics: defect passivation for high performance photodetector operation

    Energy Technology Data Exchange (ETDEWEB)

    Whitfield, M.D.; Lansley, S.P.; Gaudin, O.; Jackman, R.B. [University Coll., London (United Kingdom). Dept. of Electrical and Electronic Engineering; McKeag, R.D.; Rizvi, N.

    2000-09-01

    Deep UV, visible blind, photoconductive devices fabricated on polycrystalline CVD diamond using inter-digitated planar electrodes have shown promising characteristics. The 'as-fabricated' device performance is insufficient for many applications; a particularly demanding example is the monitoring of high power excimer lasers operating in the UV, which ideally require visible-blind, radiation hard fast UV detectors. However, post-growth treatments can strongly modify the performance level achieved. In this paper, we show that sequentially applied treatments can progressively change both the gain and speed of these devices. We have used charge sensitive deep level transient spectroscopy (Q-DLTS) to study the effect of these treatments on the defect structure of CVD material. For the first time, we report the realisation of diamond photoconductive devices capable of operating at more than 1 MHz at 193 nm. (orig.)

  3. FTIR monitoring of industrial scale CVD processes

    Science.gov (United States)

    Hopfe, V.; Mosebach, H.; Meyer, M.; Sheel, D.; Grählert, W.; Throl, O.; Dresler, B.

    1998-06-01

    The goal is to improve chemical vapour deposition (CVD) and infiltration (CVI) process control by a multipurpose, knowledge based feedback system. For monitoring the CVD/CVI process in-situ FTIR spectroscopic data has been identified as input information. In the presentation, three commonly used, and distinctly different, types of industrial CVD/CVI processes are taken as test cases: (i) a thermal high capacity CVI batch process for manufacturing carbon fibre reinforced SiC composites for high temperature applications, (ii) a continuously driven CVD thermal process for coating float glass for energy protection, and (iii) a laser stimulated CVD process for continuously coating bundles of thin ceramic fibers. The feasibility of the concept with FTIR in-situ monitoring as a core technology has been demonstrated. FTIR monitoring sensibly reflects process conditions.

  4. Solid Lubrication of Laser Grown Fluorinated Diamond Thin Films

    Science.gov (United States)

    1992-01-21

    irradiation of laser beam on the substrate surface 2 Schematic diagram showing laser CVD experimental set- up . 27 A single laser beam (YAG or Excimer) was only...0.05 to 0.2 depending upon temperature, environment, load, speed and presence of foreign material. Todate , ultra-low coefficients of friction (0.02...Laser technology for diamond film fabrication is very new and todate only a handful number of publications are available that address directly on the

  5. Two- and three-dimensional ultrananocrystalline diamond (UNCD) structures for a high resolution diamond-based MEMS technology.

    Energy Technology Data Exchange (ETDEWEB)

    Auciello, O.; Krauss, A. R.; Gruen, D. M.; Busmann, H. G.; Meyer, E. M.; Tucek, J.; Sumant, A.; Jayatissa, A.; Moldovan, N.; Mancini, D. C.; Gardos, M. N.

    2000-01-17

    Silicon is currently the most commonly used material for the fabrication of microelectromechanical systems (MEMS). However, silicon-based MEMS will not be suitable for long-endurance devices involving components rotating at high speed, where friction and wear need to be minimized, components such as 2-D cantilevers that may be subjected to very large flexural displacements, where stiction is a problem, or components that will be exposed to corrosive environments. The mechanical, thermal, chemical, and tribological properties of diamond make it an ideal material for the fabrication of long-endurance MEMS components. Cost-effective fabrication of these components could in principle be achieved by coating Si with diamond films and using conventional lithographic patterning methods in conjunction with e. g. sacrificial Ti or SiO{sub 2} layers. However, diamond coatings grown by conventional chemical vapor deposition (CVD) methods exhibit a coarse-grained structure that prevents high-resolution patterning, or a fine-grained microstructure with a significant amount of intergranular non-diamond carbon. The authors demonstrate here the fabrication of 2-D and 3-D phase-pure ultrananocrystalline diamond (UNCD) MEMS components by coating Si with UNCD films, coupled with lithographic patterning methods involving sacrificial release layers. UNCD films are grown by microwave plasma CVD using C{sub 60}-Ar or CH{sub 4}-Ar gas mixtures, which result in films that have 3--5 nm grain size, are 10--20 times smoother than conventionally grown diamond films, are extremely resistant to corrosive environments, and are predicted to have a brittle fracture strength similar to that of single crystal diamond.

  6. Optical Characterization of Diamond Synthesis Using CH3OH-H2 Gas Mixtures

    Institute of Scientific and Technical Information of China (English)

    Man Weidong; Wang Jianhua; Li Lei; Zhang Baohua; Bai Yuming

    2005-01-01

    Diamond films with high infrared transmittance have been successfully deposited using CH3OH-H2 gas mixtures through microwave plasma enhanced chemical vapor deposition (MWCVD). The primary purpose of this study is to determine the effect of the deposition conditions on the optical properties of MWCVD diamond films using CH3OH-H2 gas mixtures. Room temperature optical properties of freestanding diamond films were studied by Fourier transform IR spectroscopy. Experimental results indicated that under appropriate deposition temperature (620 ℃) and methanol concentration (5.7%), the refractive index of CVD diamond films (2.33)was comparable with that of natural diamond (2.417). The average infrared transmittance was above 65% in the middle infrared region (500 cm-1 ~ 4000 cm-1), approaching to the theoretical value of diamond (71.4%). The mechanism of growing high IR transmittance diamond films by utilizing CH3OH-H2 gas system is that the high methanol concentration used in this study makes the surface roughness of diamond films decreased by increasing the secondary nucleation density and the high O/C ratio in CH3OH-H2 gas system, improved the quality of diamond films and therefore decreased the absorption of non-diamond carbon in the films.

  7. PREFACE: Science's gem: diamond science 2009 Science's gem: diamond science 2009

    Science.gov (United States)

    Mainwood, Alison; Newton, Mark E.; Stoneham, Marshall

    2009-09-01

    diamond's exceptional properties for quantum information processing [2], a topic on which there have been many recent papers, and where a diamond colour centre single photon source is already commercially available. Biomedical applications of diamond are recognised, partly tribological and partly electrochemical, but lie outside the present group of papers. Processing and controlling diamond surfaces and interfaces with other materials in their environment are critical steps en route to exploitation. Boron-doped diamond has already found application in electro-analysis and in the bulk oxidation of dissolved species in solution [3]. Energy-related applications—ranging from high-power electronics [3] to a potential first wall of fusion reactors [4]—are further exciting potential applications. Even small and ugly diamonds have value. Their mechanical properties [5] dominate, with significant niche applications such as thermal sinks. The major applications for diamond to date exploit only a fraction of diamond's special properties: visual for status diamonds, and mechanical for working diamonds. Diamond physics reaches well beyond the usual laboratory, to the geological diamond formation processes in the Earth's mantle. Characterization of natural gem diamonds [6, 7] is one part of the detective story that allows us to understand the conditions under which they formed. It was only half a century ago that the scientific and technological challenges of diamond synthesis were met systematically. Today, most of the recent research on diamond has concentrated on synthetics, whether created using high pressure, high temperature (HPHT) techniques or chemical vapour deposition (CVD). The HPHT synthesis of diamond has advanced dramatically [8, 9] to the extent that dislocation birefringence [10] can be largely eliminated. In silicon technology, the elimination of dislocations was a major step in microelectronics. Now, even diamond can be synthesised containing virtually no

  8. Diamond Synthesis Employing Nanoparticle Seeds

    Science.gov (United States)

    Uppireddi, Kishore (Inventor); Morell, Gerardo (Inventor); Weiner, Brad R. (Inventor)

    2014-01-01

    Iron nanoparticles were employed to induce the synthesis of diamond on molybdenum, silicon, and quartz substrates. Diamond films were grown using conventional conditions for diamond synthesis by hot filament chemical vapor deposition, except that dispersed iron oxide nanoparticles replaced the seeding. This approach to diamond induction can be combined with dip pen nanolithography for the selective deposition of diamond and diamond patterning while avoiding surface damage associated to diamond-seeding methods.

  9. Atomic-Scale Kinetic Monte Carlo Simulation of {100}-Oriented Diamond Film Growth in C-H and C-H-Cl Systems by Chemical Vapour Deposition

    Institute of Scientific and Technical Information of China (English)

    安希忠; 张禹; 刘国权; 秦湘阁; 王辅忠; 刘胜新

    2002-01-01

    We simulate the { 100}-oriented diamond film growth of chemical vapour deposition (CVD) under different modelsin C-H and C-H-CI systems in an atomic scale by using the revised kinetic Monte Carlo method. The sirnulationresults show that: (1) the CVD diamond flm growth in the C-H system is suitable for high substrate temperature,and the flm surface roughness is very coarse; (2) the CVD diamond film can grow in the C-H-C1 system eitherat high temperature or at low temperature, and the film quality is outstanding; (3) atomic CI takes ala activerole for the growth of diamond film, especially at low temperatures. The concentration of atomic C1 should becontrolled in a proper range.

  10. Diagnostic of fusion neutrons on JET tokamak using diamond detector

    Science.gov (United States)

    Nemtsev, G.; Amosov, V.; Marchenko, N.; Meshchaninov, S.; Rodionov, R.; Popovichev, S.; JET EFDA contributors

    2014-08-01

    In 2011-2012, an experimental campaign with a significant yield of fusion neutrons was carried out on the JET tokamak. During this campaign the facility was equipped with two diamond detectors based on natural and artificial CVD diamond. These detectors were designed and manufactured in State Research Center of Russian Federation TRINITI. The detectors measure the flux of fast neutrons with energies above 0.2 MeV. They have been installed in the torus hall and the distance from the center of plasma was about 3 m. For some of the JET pulses in this experiment, the neutron flux density corresponded to the operational conditions in collimator channels of ITER Vertical Neutron Camera. The main objective of diamond monitors was the measurement of total fast neutron flux at the detector location and the estimation of the JET total neutron yield. The detectors operate as threshold counters. Additionally a spectrometric measurement channel has been configured that allowed us to distinguish various energy components of the neutron spectrum. In this paper we describe the neutron signal measuring and calibration procedure of the diamond detector. Fluxes of DD and DT neutrons at the detector location were measured. It is shown that the signals of total neutron yield measured by the diamond detector correlate with signals measured by the main JET neutron diagnostic based on fission chambers with high accuracy. This experiment can be considered as a successful test of diamond detectors in ITER-like conditions.

  11. 77 FR 73420 - Diamond Sawblades and Parts Thereof From the Republic of Korea: Preliminary Results of...

    Science.gov (United States)

    2012-12-10

    ... Balbontin, AD/ CVD Operations, Office 1, Import Administration, International Trade Administration, U.S... 76128 (December 6, 2011), remains dispositive. Fraud Allegation The petitioner, Diamond Sawblades... in the first administrative review at which the facts surrounding the fraud allegation were examined...

  12. Diamond-coated probe head for measurements in the deep SOL and beyond

    DEFF Research Database (Denmark)

    Schrittwieser, R.; Xu, G. S.; Yan, Ning;

    We have tested two cylindrical graphite probe heads coated by a layer of electrically isolating UNCD (Ultra Nano-Crystalline Diamond) using a CVD (Chemical Vapour Deposition) method. The probe heads were mounted on the reciprocating probe manipulator of the Experimental Advanced Superconducting T...

  13. Thermoluminescent characteristic of MWCVD diamond films exposed to gamma dose

    Energy Technology Data Exchange (ETDEWEB)

    Gastelum, S.; Chernov, V.; Melendrez, R.; Barboza F, M. [Centro de Investigacion en Fisica, Universidad de Sonora, A.P. 5-088, 83190 Hermosillo, Sonora (Mexico); Cruz Z, E. [ICN-UNAM, A.P. 70-543, 04510 Mexico D.F. (Mexico)

    2006-07-01

    The thermoluminescence measurements of microwave plasma assisted CVD diamond of 6 and 12 {mu}m thick films grown on (100) silicon substrates indicated the existence of a suitable thermoluminescence dosimetric peak around 310 C. The range of linearity of the 6 {mu}m diamond sample exposed to 0.67 Gy/min {sup 60} Co gamma radiation is observed up to 125 Gy being non -linear for higher doses. The 12 {mu} m displayed lower thermoluminescence efficiency as compared to the 6 {mu}m specimen. The discrepancy was attributed to the non uniform distribution- of nucleated diamond on the substrate as revealed by SEM micrograph of the samples. The thermoluminescence behaviour of the samples exhibited very low thermal fading and show a good reproducibity of the thermoluminescence signal. The kinetics parameters were calculated by Initial Rise and Chen methods. (Author)

  14. High speed diamond photoconductive devices for UV detection

    Energy Technology Data Exchange (ETDEWEB)

    Whitfield, M.D.; Lansley, St.P.; Gaudin, O.; Jackman, R.B. [University Coll., London (United Kingdom). Dept. of Electrical and Electronic Engineering; McKeag, R.D. [Centronic Ltd., Cryodon (United Kingdom); Rizvi, N. [Exitech Ltd, Oxford (United Kingdom)

    2001-05-16

    Deep UV visible blind photoconductive devices can be fabricated on polycrystalline CVD diamond, a material that is intrinsically radiation hard and visible blind. However, the performance of detectors fabricated on as-grown material is insufficient to meet the requirements of many laser-based applications. In this paper, it is shown that sequentially applied post-growth treatments can progressively change both the gain and speed of these devices. Charge sensitive deep level transient spectroscopy (Q-DLTS) and transient photoconductivity (TPC) has been used to study the effect of these treatments on the defect structure of our thin film diamond detector material. For the first time, we report the successful operation of a diamond photoconductive device with linear bias and fluence response characteristics at more than 1 kHz at 193 nm. (orig.)

  15. Diamond mosaic crystals for neutron instrumentation: First experimental results

    Energy Technology Data Exchange (ETDEWEB)

    Freund, A.K., E-mail: kafreund@free.f [Via Cordis, 92 Rue Abbe de l' Epee, F-33000 Bordeaux (France); Institut Max von Laue-Paul Langevin, B.P. 156, F-38042 Grenoble Cedex (France); Gsell, S.; Fischer, M.; Schreck, M. [Institut fuer Physik, Universitaet Augsburg, D-86135 Augsburg (Germany); Andersen, K.H.; Courtois, P. [Institut Max von Laue-Paul Langevin, B.P. 156, F-38042 Grenoble Cedex (France); Borchert, G. [Forschungsneutronenquelle FRM2, D-85747 Garching (Germany); Skoulatos, M. [Helmholtz Center Berlin for Materials and Energy, D-14109 Berlin (Germany)

    2011-04-01

    Diamond single crystals were recently proposed as monochromators of unprecedented performance (Freund, 2009). In the present paper we describe how diamond crystals with a suitable mosaic spread can be produced using a specific plasma CVD technique. Up to 2 mm thick samples with an average mosaic spread of 0.2{sup o} have been produced. We report on X- and gamma-ray characterisation checking the uniformity of the mosaic structure and present the results of a first study regarding the neutron reflection properties of this outstanding material. These promising results show that the diamond diffraction properties are not too far from the theoretical expectations. For example, 34% peak reflectivity has been obtained for a 1 mm thick crystal at 1 A wavelength.

  16. Effect of Plasma Boronitriding on Diamond Nucle-ation and Growth onto Cemented Carbide Substrates

    Institute of Scientific and Technical Information of China (English)

    满卫东; 汪建华; 马志斌; 王传新

    2002-01-01

    Plasma boronitriding has been successfully employed to overcome the difficulty in diamond growth on ferrous-based substrates. Commercial cobalt-sintered, tungsten-cemented carbides (WC(Co)) were pretreated by a plasma boronitriding method, diamond was then deposited by microwave-enhanced chemical vapor deposition (MPCVD). The deposited films were characterized by scanning electron microscopy and Raman spectroscopy. Continuous diamond films with a sharp characteristic Raman peak of 1334 cm-1 were grown and adhered well on the boronitrided region of the cemented carbide substrates. On the other hand, a mixture of diamond crystallites, amorphous carbon and graphitic carbon was loosely deposited on the unboronitrided region. A cobalt inert thin layer formed after plasma boronitriding pretreatment enabled the subsequent nucleation and growth of a high-quality CVD diamond.

  17. Magnetic and cytotoxic properties of hot-filament chemical vapour deposited diamond

    Energy Technology Data Exchange (ETDEWEB)

    Zanin, Hudson, E-mail: hudsonzanin@gmail.com [Faculdade de Engenharia Eletrica e Computacao, Departamento de Semicondutores, Instrumentos e Fotonica, Universidade Estadual de Campinas, UNICAMP, Av. Albert Einstein N.400, CEP 13 083-852 Campinas, Sao Paulo (Brazil); Peterlevitz, Alfredo Carlos; Ceragioli, Helder Jose [Faculdade de Engenharia Eletrica e Computacao, Departamento de Semicondutores, Instrumentos e Fotonica, Universidade Estadual de Campinas, UNICAMP, Av. Albert Einstein N.400, CEP 13 083-852 Campinas, Sao Paulo (Brazil); Rodrigues, Ana Amelia; Belangero, William Dias [Laboratorio de Biomateriais em Ortopedia, Faculdade de Ciencias Medicas, Universidade Estadual de Campinas, Rua Cinco de Junho 350 CEP 13083970, Campinas, Sao Paulo (Brazil); Baranauskas, Vitor [Faculdade de Engenharia Eletrica e Computacao, Departamento de Semicondutores, Instrumentos e Fotonica, Universidade Estadual de Campinas, UNICAMP, Av. Albert Einstein N.400, CEP 13 083-852 Campinas, Sao Paulo (Brazil)

    2012-12-01

    Microcrystalline (MCD) and nanocrystalline (NCD) magnetic diamond samples were produced by hot-filament chemical vapour deposition (HFCVD) on AISI 316 substrates. Energy Dispersive X-ray Spectroscopy (EDS) measurements indicated the presence of Fe, Cr and Ni in the MCD and NCD samples, and all samples showed similar magnetisation properties. Cell viability tests were realised using Vero cells, a type of fibroblastic cell line. Polystyrene was used as a negative control for toxicity (NCT). The cells were cultured under standard cell culture conditions. The proliferation indicated that these magnetic diamond samples were not cytotoxic. - Highlights: Black-Right-Pointing-Pointer Polycrystalline diamonds doped with Fe, Cr and Ni acquire ferromagnetic properties. Black-Right-Pointing-Pointer CVD diamonds have been prepared with magnetic and semiconductor properties. Black-Right-Pointing-Pointer Micro/nanocrystalline diamonds show good cell viability with fibroblast proliferation.

  18. Low resistance polycrystalline diamond thin films deposited by hot filament chemical vapour deposition

    Indian Academy of Sciences (India)

    Mahtab Ullah; Ejaz Ahmed; Abdelbary Elhissi; Waqar Ahmed

    2014-05-01

    Polycrystalline diamond thin films with outgrowing diamond (OGD) grains were deposited onto silicon wafers using a hydrocarbon gas (CH4) highly diluted with H2 at low pressure in a hot filament chemical vapour deposition (HFCVD) reactor with a range of gas flow rates. X-ray diffraction (XRD) and SEM showed polycrystalline diamond structure with a random orientation. Polycrystalline diamond films with various textures were grown and (111) facets were dominant with sharp grain boundaries. Outgrowth was observed in flowerish character at high gas flow rates. Isolated single crystals with little openings appeared at various stages at low gas flow rates. Thus, changing gas flow rates had a beneficial influence on the grain size, growth rate and electrical resistivity. CVD diamond films gave an excellent performance for medium film thickness with relatively low electrical resistivity and making them potentially useful in many industrial applications.

  19. Fracture Characteristics of Monolayer CVD-Graphene

    Science.gov (United States)

    Hwangbo, Yun; Lee, Choong-Kwang; Kim, Sang-Min; Kim, Jae-Hyun; Kim, Kwang-Seop; Jang, Bongkyun; Lee, Hak-Joo; Lee, Seoung-Ki; Kim, Seong-Su; Ahn, Jong-Hyun; Lee, Seung-Mo

    2014-03-01

    We have observed and analyzed the fracture characteristics of the monolayer CVD-graphene using pressure bulge testing setup. The monolayer CVD-graphene has appeared to undergo environmentally assisted subcritical crack growth in room condition, i.e. stress corrosion cracking arising from the adsorption of water vapor on the graphene and the subsequent chemical reactions. The crack propagation in graphene has appeared to be able to be reasonably tamed by adjusting applied humidity and stress. The fracture toughness, describing the ability of a material containing inherent flaws to resist catastrophic failure, of the CVD-graphene has turned out to be exceptionally high, as compared to other carbon based 3D materials. These results imply that the CVD-graphene could be an ideal candidate as a structural material notwithstanding environmental susceptibility. In addition, the measurements reported here suggest that specific non-continuum fracture behaviors occurring in 2D monoatomic structures can be macroscopically well visualized and characterized.

  20. Thin film deposition of diamond using normal paraffins as source of diamond nucleation centers

    Energy Technology Data Exchange (ETDEWEB)

    Ershova, A., E-mail: ershovaangelina@mail.ru [Nano-Technology Laboratory, Triangle Inc., 01079 (Ukraine); Eizenbraun, A. [Nano-Technology Laboratory, Triangle Inc., 01079 (Ukraine)

    2012-11-15

    Highlights: ► Paraffin compounds are diamond nucleation sources. ► Thermoconductivity of Cu–DTF device is higher than such conductivity of Cu. ► DTF growth in HFCVD reactor is not linear function of time. -- Abstract: We propose a process for diamond thin film (DTF) deposition using normal paraffins (nP) as source of diamond nucleation centers. We deposited micro-crystalline diamond thin films (MCDTF) on a Cu substrate using Hot Filament CVD (HFCVD) and Passive Pt/Pd Surface Catalysis (PPt/PdSC) methods. Beeswax and a 1:1 mixture of normal paraffins of the general formula CH{sub 3}(CH{sub 2}){sub n}CH{sub 3} with n = 22 and 26 were tested as nP starting material. The films obtained were characterized by scanning electronic microscopy (SEM), Raman scattering temperature dependent spectroscopy and X-ray diffraction (XRD) methods, all of which confirmed that the deposited material is MCDTF.

  1. Fracture Characteristics of Monolayer CVD-Graphene

    OpenAIRE

    Hwangbo, Yun; Lee, Choong-Kwang; Kim, Sang-Min; Kim, Jae-Hyun; Kim, Kwang-Seop; Jang, Bongkyun; Lee, Hak-Joo; Lee, Seoung-Ki; Kim, Seong-Su; Ahn, Jong-Hyun; Lee, Seung-Mo

    2014-01-01

    We have observed and analyzed the fracture characteristics of the monolayer CVD-graphene using pressure bulge testing setup. The monolayer CVD-graphene has appeared to undergo environmentally assisted subcritical crack growth in room condition, i.e. stress corrosion cracking arising from the adsorption of water vapor on the graphene and the subsequent chemical reactions. The crack propagation in graphene has appeared to be able to be reasonably tamed by adjusting applied humidity and stress. ...

  2. Diamond tool machining of materials which react with diamond

    Science.gov (United States)

    Lundin, Ralph L.; Stewart, Delbert D.; Evans, Christopher J.

    1992-01-01

    Apparatus for the diamond machining of materials which detrimentally react with diamond cutting tools in which the cutting tool and the workpiece are chilled to very low temperatures. This chilling halts or retards the chemical reaction between the workpiece and the diamond cutting tool so that wear rates of the diamond tool on previously detrimental materials are comparable with the diamond turning of materials which do not react with diamond.

  3. Enhancement of the nucleation of smooth and dense nanocrystalline diamond films by using molybdenum seed layers

    Science.gov (United States)

    Buijnsters, J. G.; Vázquez, L.; van Dreumel, G. W. G.; ter Meulen, J. J.; van Enckevort, W. J. P.; Celis, J. P.

    2010-11-01

    A method for the nucleation enhancement of nanocrystalline diamond (NCD) films on silicon substrates at low temperature is discussed. A sputter deposition of a Mo seed layer with thickness 50 nm on Si substrates was applied followed by an ultrasonic seeding step with nanosized detonation diamond powders. Hot-filament chemical vapor deposition (HF-CVD) was used to nucleate and grow NCD films on substrates heated up at 550 °C. The nucleation of diamond and the early stages of NCD film formation were investigated at different methane percentages in methane/hydrogen gas mixtures by atomic force microscopy, micro-Raman spectroscopy, scanning electron microscopy, and grazing incidence x-ray analyses in order to gain specific insight in the nucleation process of NCD films. The nucleation kinetics of diamond on the Mo-coated Si substrates was found to be up to ten times higher than on blank Si substrates. The enhancement of the nucleation of diamond on thin Mo interlayers results from two effects, namely, (a) the nanometer rough Mo surface shows an improved embedding of ultrasonically introduced nanosized diamond seeds that act as starting points for the diamond nucleation during HF-CVD and (b) the rapid carbonization of the Mo surface causes the formation of Mo2C onto which diamond easily nucleates. The diamond nucleation density progressively increases at increasing methane percentages and is about 5×1010 cm-2 at 4.0% methane. The improved nucleation kinetics of diamond on Mo interlayers facilitates the rapid formation of NCD films possessing a very low surface roughness down to ˜6 nm, and allows a submicron thickness control.

  4. A synthetic diamond probe for low-energy X-ray dose measurements.

    Science.gov (United States)

    Assiamah, M; Nam, T L; Keddy, R J

    2007-05-01

    The desirable physical properties of diamond have made the mineral a choice material in radiation measurements. Diamond detectors are currently used extensively in high-energy physics. Their use for low-energy beams such as, for example, in mammography X-ray beams however, has not been fully investigated. This paper describes a diamond probe which has been constructed for the evaluation, as the radiation sensing material, of polycrystalline synthetic diamonds produced by chemical vapour deposition (CVD). The specimens were fabricated in wafer form and so the exposure orientation geometry of the diamond wafers, to give optimum absorption of the incident X-ray beam, was also investigated both experimentally and theoretically. The samples were characterized to obtain information regarding the elemental impurity levels, especially nitrogen, and consequently to establish the material quality. Nitrogen impurities and concentration levels in the diamond lattice have been shown to have a profound effect on the radiation detection properties of diamond. The probe described has the diamond surfaces metallized with titanium, platinum and gold to provide ohmic contacts. The probe was connected independently to both Wellhöfer Dosimetrie (model CU 500) and PTW Unidos E commercial electrometers. In all of the measurements, the incident radiation beam was normal to the edge of the diamond wafer to optimize absorption of the X-ray beam after establishing that this orientation was the optimum geometry. The results of the study are presented in both tabular and graphical forms.

  5. Grating-assisted coupling to nanophotonic circuits in microcrystalline diamond thin films

    Directory of Open Access Journals (Sweden)

    Patrik Rath

    2013-05-01

    Full Text Available Synthetic diamond films can be prepared on a waferscale by using chemical vapour deposition (CVD on suitable substrates such as silicon or silicon dioxide. While such films find a wealth of applications in thermal management, in X-ray and terahertz window design, and in gyrotron tubes and microwave transmission lines, their use for nanoscale optical components remains largely unexplored. Here we demonstrate that CVD diamond provides a high-quality template for realizing nanophotonic integrated optical circuits. Using efficient grating coupling devices prepared from partially etched diamond thin films, we investigate millimetre-sized optical circuits and achieve single-mode waveguiding at telecoms wavelengths. Our results pave the way towards broadband optical applications for sensing in harsh environments and visible photonic devices.

  6. Optical engineering of diamond

    CERN Document Server

    Rabeau, James R

    2013-01-01

    This is the first comprehensive book on the engineering of diamond optical devices. It will give readers an up-to-date account of the properties of optical quality synthetic diamond (single crystal, nanodiamond and polycrystalline) and reviews the large and growing field of engineering of diamond-based optical devices, with applications in quantum computation, nano-imaging, high performance lasers, and biomedicine. It aims to provide scientists, engineers and physicists with a valuable resource and reference book for the design and performance of diamond-based optical devices.

  7. Nano- and microcrystalline diamond deposition on pretreated WC-Co substrates: structural properties and adhesion

    Science.gov (United States)

    Fraga, M. A.; Contin, A.; Rodríguez, L. A. A.; Vieira, J.; Campos, R. A.; Corat, E. J.; Trava Airoldi, V. J.

    2016-02-01

    Many developments have been made to improve the quality and adherence of CVD diamond films onto WC-Co hard metal tools by the removing the cobalt from the substrate surface through substrate pretreatments. Here we compare the efficiency of three chemical pretreatments of WC-Co substrates for this purpose. First, the work was focused on a detailed study of the composition and structure of as-polished and pretreated substrate surfaces to characterize the effects of the substrate preparation. Considering this objective, a set of WC-9% Co substrates, before and after pretreatment, was analyzed by FEG-SEM, EDS and x-ray diffraction (XRD). The second stage of the work was devoted to the evaluation of the influence of seeding process, using 4 nm diamond nanoparticles, on the morphology and roughness of the pretreated substrates. The last and most important stage was to deposit diamond coatings with different crystallite sizes (nano and micro) by hot-filament CVD to understand fully the mechanism of growth and adhesion of CVD diamond films on pretreated WC-Co substrates. The transition from nano to microcrystalline diamond was achieved by controlling the CH4/H2 gas ratio. The nano and microcrystalline samples were grown under same time at different substrate temperatures 600 °C and 800 °C, respectively. The different substrate temperatures allowed the analysis of the cobalt diffusion from the bulk to the substrate surface during CVD film growth. Furthermore, it was possible to evaluate how the coating adhesion is affected by the diffusion. The diamond coatings were characterized by Raman spectroscopy, XRD, EDS, FEG-SEM, atomic force microscope and 1500 N Rockwell indentation to evaluate the adhesion.

  8. CVD 908, CVD 908-htrA, and CVD 909 live oral typhoid vaccines: a logical progression.

    Science.gov (United States)

    Tacket, Carol O; Levine, Myron M

    2007-07-15

    Typhoid fever remains an important public health problem in many parts of the world. Despite the availability of oral Ty21a (Vivotif; Berna Biotech) and parenteral Vi polysaccharide vaccine (Typhim Vi; Aventis Pasteur), improved typhoid fever vaccines have been sought. These include a series of vaccine candidates developed at the Center for Vaccine Development, University of Maryland, based on attenuation of Salmonella enterica serovar Typhi by deletions in the aroC, aroD, and htrA genes. These vaccine candidates, designated "CVD 908," "CVD 908-htrA," and "CVD 909," have been developed and tested in volunteers with variable success. This review summarizes the clinical data that directed the logical progression of this vaccine development strategy.

  9. a Design of Experiment Study of the Nucleation of Chemical Vapor Deposited Diamond Films.

    Science.gov (United States)

    Tang, Chi

    1995-01-01

    Because of its property, diamond has a unique role in the semiconductor and tool industry. As diamond synthesis technology advances, more and more applications are emerging. However, in order to take advantage of its exceptional property, reliable control of nucleation and growth must be accomplished. In this study, the author systematically studies the nucleation process in chemical vapor deposition (CVD) of diamonds. Among many important intricacies concerning diamond nucleation on foreign surfaces, this study addresses the following issues: the role of ultrasonic pre-treatment in CVD; the correlation between hot filament chemical vapor deposition (HFCVD) and microwave assisted chemical vapor deposition (MACVD) control parameters and the nucleation processes; the role of biasing substrates on the nucleation density in MACVD; the correlation between parameters of biasing substrates and the nucleation density; the reliable control of nucleation in CVD diamond synthesis. To achieve the goal of this research, a multi -purpose deposition system was built enabling the author to eliminate unnecessary variables in the deposition process. To ensure the accuracy of the nucleation effects of parameters investigated, great effort was made to calibrate measurement instruments so that noise or fluctuations in the experiments were minimized. The implementation of design of experiments (DOE), a systematic investigating technique, vastly improved the efficiency of this study over the less sophisticated empirical approach. In addition, DOE allowed the author to quantitatively estimate the effects of control parameters. Finally, diamond deposition was confirmed by Scanning Electron microscope, Micro Raman Scattering and Rutherford Backscattering. This research has successfully implemented DOE in estimating the effects of diamond nucleation quantitatively. The mechanism of ultrasonic pre-treatment is explained, and its effects are ascribed to seeding. The effects of primary CVD

  10. Diamond films: Historical perspective

    Energy Technology Data Exchange (ETDEWEB)

    Messier, R. [Pennsylvania State Univ., University Park (United States)

    1993-01-01

    This section is a compilation of notes and published international articles about the development of methods of depositing diamond films. Vapor deposition articles are included from American, Russian, and Japanese publications. The international competition to develop new deposition methodologies is stressed. The current status of chemical vapor deposition of diamond is assessed.

  11. Investing in Diamonds

    NARCIS (Netherlands)

    Renneboog, Luc

    2015-01-01

    This paper examines the risk-return characteristics of investment grade gems (white diamonds, colored diamonds and other types of gems including sapphires, rubies, and emeralds). The transactions are coming from gem auctions and span the period 1999-2012. Over our time frame, the annual nominal USD

  12. Investing in Diamonds

    NARCIS (Netherlands)

    Renneboog, Luc

    2015-01-01

    This paper examines the risk-return characteristics of investment grade gems (white diamonds, colored diamonds and other types of gems including sapphires, rubies, and emeralds). The transactions are coming from gem auctions and span the period 1999-2012. Over our time frame, the annual nominal USD

  13. Knowledge of risk factors for diabetes or cardiovascular disease (CVD) is poor among individuals with risk factors for CVD.

    Science.gov (United States)

    Kilkenny, Monique F; Dunstan, Libby; Busingye, Doreen; Purvis, Tara; Reyneke, Megan; Orgill, Mary; Cadilhac, Dominique A

    2017-01-01

    There is limited evidence on whether having pre-existing cardiovascular disease (CVD) or risk factors for CVD such as diabetes, ensures greater knowledge of risk factors important for motivating preventative behaviours. Our objective was to compare knowledge among the Australian public participating in a health check program and their risk status. Data from the Stroke Foundation 'Know your numbers' program were used. Staff in community pharmacies provided opportunistic health checks (measurement of blood pressure and diabetes risk assessment) among their customers. Participants were categorised: 1) CVD ± risk of CVD: history of stroke, heart disease or kidney disease, and may have risk factors; 2) risk of CVD only: reported having high blood pressure, high cholesterol, diabetes or atrial fibrillation; and 3) CVD risk free (no CVD or risk of CVD). Multivariable logistic regression analyses were performed including adjustment for age and sex. Among 4,647 participants, 12% had CVD (55% male, 85% aged 55+ years), 47% were at risk of CVD (40% male, 72% 55+ years) and 41% were CVD risk free (33% male, 27% 55+ years). Participants with CVD (OR: 0.66; 95% CI: 0.55, 0.80) or risk factors for CVD (OR: 0.65; 95% CI: 0.57, 0.73) had poorer knowledge of the risk factors for diabetes/CVD compared to those who were CVD risk free. After adjustment, only participants with risk factors for CVD (OR: 0.80; 95% CI: 0.69, 0.93) had poorer knowledge. Older participants (55+ years) and men had poorer knowledge of diabetes/CVD risk factors and complications of diabetes. Participants with poorer knowledge of risk factors were older, more often male or were at risk of developing CVD compared with those who were CVD risk free. Health education in these high risk groups should be a priority, as diabetes and CVD are increasing in prevalence throughout the world.

  14. Substrate Strengthening of CVD Coated Steels

    Institute of Scientific and Technical Information of China (English)

    O.Kessler; M.Heidkamp; F.Hoffmann; P.Mayr

    2004-01-01

    Properties of components and tools can be improved by the combination of coating and heat treatment processes due to the addition of single process advantages and due to the utilization of process interactions. Several low and high alloyed, structural and tool steels (AISI 4140, 52100, H13, A2, D2, etc.) have been treated by CVD-TiN-coating plus laser beam hardening respectively carburizing plus CVD-TiN-coating. Homogeneous, dense TiN-coatings with high hardness,high compressive residual stresses and good adhesion were supported by high strength substrate surfaces. Especially CVD plus laser beam hardening offers the possibility to reduce distortion due to the small heated surface volume.

  15. STABLE DIAMOND GRINDING

    Directory of Open Access Journals (Sweden)

    Yury Gutsalenko

    2010-06-01

    Full Text Available The paper generalizes on the one hand theory of kinematic-geometrical simulation of grinding processes by means of tools with working part as binding matrix with abrasive grains located in it in random manner, for example diamond grains, and on the other hand practical performance of combined grinding process, based on introduction of additional energy as electric discharges and called by the organization-developer (Kharkov Polytechnic Institute «diamond-spark grinding» as applied to processing by means of diamond wheel. Implementation of diamond-spark grinding technologies on the basis of developed generalized theoretical approach allows to use the tool with prescribed tool-life, moreover to make the most efficient use of it up to full exhausting of tool-life, determined by diamond-bearing thickness. Development is directed forward computer-aided manufacturing.

  16. Diamond Integrated Optomechanical Circuits

    CERN Document Server

    Rath, Patrik; Nebel, Christoph; Wild, Christoph; Pernice, Wolfram H P

    2013-01-01

    Diamond offers unique material advantages for the realization of micro- and nanomechanical resonators due to its high Young's modulus, compatibility with harsh environments and superior thermal properties. At the same time, the wide electronic bandgap of 5.45eV makes diamond a suitable material for integrated optics because of broadband transparency and the absence of free-carrier absorption commonly encountered in silicon photonics. Here we take advantage of both to engineer full-scale optomechanical circuits in diamond thin films. We show that polycrystalline diamond films fabricated by chemical vapour deposition provide a convenient waferscale substrate for the realization of high quality nanophotonic devices. Using free-standing nanomechanical resonators embedded in on-chip Mach-Zehnder interferometers, we demonstrate efficient optomechanical transduction via gradient optical forces. Fabricated diamond resonators reproducibly show high mechanical quality factors up to 11,200. Our low cost, wideband, carri...

  17. Diamond-based protective layer for optical biosensors

    Science.gov (United States)

    Majchrowicz, D.; Ficek, M.; Baran, T.; WÄ sowicz, M.; Struk, P.; Jedrzejewska-Szczerska, M.

    2016-09-01

    Optical biosensors have become a powerful alternative to the conventional ways of measurement owing to their great properties, such as high sensitivity, high dynamic range, cost effectiveness and small size. Choice of an optical biosensor's materials is an important factor and impacts the quality of the obtained spectra. Examined biological objects are placed on a cover layer which may react with samples in a chemical, biological and mechanical way, therefore having a negative impact on the measurement reliability. Diamond, a metastable allotrope of carbon with sp3 hybridization, shows outstanding properties such as: great chemical stability, bio-compatibility, high thermal conductivity, wide bandgap and optical transparency. Additionally it possesses great mechanical durability, which makes it a long-lasting material. The protective diamond thin films were deposited on the substrate using Microwave Plasma Assisted Chemical Vapor Deposition (MW PA CVD) system. The surface morphology and roughness was assessed with atomic force microscopy and profilometry. We have performed a series of measurements to assess the biocompatibility of diamond thin films with whole blood. The results show that thin diamond protective layer does not affect the red blood cells, while retaining the sensors high resolution and dynamic range of measurement. Therefore, we conclude that diamond thin films are a viable protective coating for optical biosensors, which allows to examine many biological elements. We project that it can be particularly useful not only for biological objects but also under extreme conditions like radioactive or chemically aggressive environments and high temperatures.

  18. Optical properties of femtosecond laser-treated diamond

    Science.gov (United States)

    Calvani, P.; Bellucci, A.; Girolami, M.; Orlando, S.; Valentini, V.; Lettino, A.; Trucchi, D. M.

    2014-10-01

    A laser-induced periodic surface structure (LIPSS) has been fabricated on polycrystalline diamond by an ultrashort Ti:Sapphire pulsed laser source ( λ = 800 nm, P = 3 mJ, 100 fs) in a high vacuum chamber (LIPSS with a ripple period of about 170 nm, shorter than the laser wavelength. Raman spectra of processed sample do not point out any evident sp 2 content, and diamond peak presents a right shift, indicating a compressive stress. The investigation of optical properties of fs-laser surface textured diamond is reported. Spectral photometry in the range 200/2,000 nm wavelength shows a significant increase of visible and infrared absorption (more than 80 %) compared to untreated specimens (less than 40 %). The analysis of optical characterization data highlights a close relationship between fabricated LIPSS and absorption properties, confirming the optical effectiveness of such a treatment as a light-trapping structure for diamond: these properties, reported for the first time, open the path for new applications of CVD diamond.

  19. Interlayer utilization (including metal borides) for subsequent deposition of NSD films via microwave plasma CVD on 316 and 440C stainless steels

    Science.gov (United States)

    Ballinger, Jared

    . Surface boriding was implemented using the novel method of microwave plasma CVD with a mixture of hydrogen and diborane gases. On 440C bearings, dual phase boride layers of Fe2B and FeB were formed which supported adhered nanostructured diamond films. Continuity of the films was not seamless with limited regions remaining uncoated potentially corresponding to delamination of the film as evidenced by the presence of tubular structures presumably composed of sp2 bonded carbon. Surface boriding of 316 stainless steel discs was conducted at various powers and pressures to achieve temperatures ranging from 550-800 °C. The substrate boriding temperature was found to substantially influence the resultant interlayer by altering the metal boride(s) present. The lowest temperatures produced an interlayer where CrB was the single detected phase, higher temperatures yielded the presence of only Fe2B, and a combination of the two phases resulted from an intermediate boriding temperature. Compared with the more common, commercialized boriding methods, this a profound result given the problems posed by the FeB phase in addition to other advantages offered by CVD processes and microwave generated plasmas in general. Indentation testing of the boride layers revealed excellent adhesion strength for all borided interlayers, and above all, no evidence of cracking was observed for a sole Fe2B phase. As with boriding of 440C bearings, subsequent diamond deposition was achieved on these interlayers with substantially improved adhesion strength relative to diamond coated TiN interlayers. Both XRD and Raman spectroscopy confirmed a nanostructured diamond film with interfacial chromium carbides responsible for enhanced adhesion strength. Interlayers consisting solely of Fe2B have displayed an ability to support fully continuous nanostructured diamond films, yet additional study is required for consistent reproduction. This is in good agreement with initial work on pack borided high alloy steels

  20. Effect of Boron-Doped Diamond Interlayer on Cutting Performance of Diamond Coated Micro Drills for Graphite Machining

    Directory of Open Access Journals (Sweden)

    Zhiming Zhang

    2013-07-01

    Full Text Available Thin boron doped diamond (BDD film is deposited from trimethyl borate/acetone/hydrogen mixture on Co-cemented tungsten carbide (WC-Co micro drills by using the hot filament chemical vapor deposition (HFCVD technique. The boron peak on Raman spectrum confirms the boron incorporation in diamond film. This film is used as an interlayer for subsequent CVD of micro-crystalline diamond (MCD film. The Rockwell indentation test shows that boron doping could effectively improve the adhesive strength on substrate of as deposited thin diamond films. Dry drilling of graphite is chosen to check the multilayer (BDD + MCD film performance. For the sake of comparison, machining tests are also carried out under identical conditions using BDD and MCD coated micro drills with no interlayer. The wear mechanism of the tools has been identified and correlated with the criterion used to evaluate the tool life. The results show that the multilayer (BDD + MCD coated micro drill exhibits the longest tool life. Therefore, thin BDD interlayer is proved to be a new viable alternative and a suitable option for adherent diamond coatings on micro cutting tools.

  1. Synthesis of SiV-diamond particulates via the microwave plasma chemical deposition of ultrananocrystalline diamond on soda-lime glass fibers

    Science.gov (United States)

    Kunuku, Srinivasu; Chen, Yen-Chun; Yeh, Chien-Jui; Chang, Wen-Hao; Manoharan, Divinah; Leou, Keh-Chyang; Lin, I.-Nan

    2016-10-01

    We report the synthesis of silicon-vacancy (SiV) incorporated spherical shaped ultrananocrystalline diamond (SiV-UNCD) particulates (size ∼1 μm) with bright luminescence at 738 nm. For this purpose, different granular structured polycrystalline diamond films and particulates were synthesized by using three different kinds of growth plasma conditions on the three types of substrate materials in the microwave plasma enhanced CVD process. The grain size dependent photoluminescence properties of nitrogen vacancy (NV) and SiV color centers have been investigated for different granular structured diamond samples. The luminescence of NV center and the associated phonon sidebands, which are usually observed in microcrystalline diamond and nanocrystalline diamond films, were effectively suppressed in UNCD films and UNCD particulates. Micron sized SiV-UNCD particulates with bright SiV emission has been attained by transfer of SiV-UNCD clusters on soda-lime glass fibers to inverted pyramidal cavities fabricated on Si substrates by the simple crushing of UNCD/soda-lime glass fibers in deionized water and ultrasonication. Such a plasma enhanced CVD process for synthesizing SiV-UNCD particulates with suppressed NV emission is simple and robust to attain the bright SiV-UNCD particulates to employ in practical applications.

  2. The diamond time of flight detector of the TOTEM experiment

    Science.gov (United States)

    Berretti, Mirko

    2017-02-01

    This contribution describes the design and the performance of a novel timing detector developed by the TOTEM Collaboration. The detector will be installed inside the TOTEM Roman Pots (RPs) and will measure the Time-Of-Flight (TOF) of the protons produced in the central diffractive (CD) interactions at the LHC. In particular, the measurement of the proton TOF allows the determination of the vertex longitudinal position where the protons are produced, thus allowing the protons association with one of the vertices reconstructed by the CMS detectors. The TOF detector is based on single crystal CVD (scCVD) diamond plates and it is designed in order to measure the protons TOF with 50 ps time resolution. To achieve this performance, a dedicated fast and low noise electronics for the signal amplification has been developed. Indeed, while diamond sensors have lower noise and faster signals than silicon sensors, the amount of charge released in the medium is lower. The digitization of the diamond signal is performed sampling the waveform at 10 GSa/s with the SAMPIC chip. The performance of the first TOF detector installed in the LHC in November 2015 will be reported. An overview of the clock distribution system and of the control system which interfaces the timing detectors to the experiment DAQ is finally given.

  3. Investigation of electrically-active deep levels in single-crystalline diamond by particle-induced charge transient spectroscopy

    Science.gov (United States)

    Kada, W.; Kambayashi, Y.; Ando, Y.; Onoda, S.; Umezawa, H.; Mokuno, Y.; Shikata, S.; Makino, T.; Koka, M.; Hanaizumi, O.; Kamiya, T.; Ohshima, T.

    2016-04-01

    To investigate electrically-active deep levels in high-resistivity single-crystalline diamond, particle-induced charge transient spectroscopy (QTS) techniques were performed using 5.5 MeV alpha particles and 9 MeV carbon focused microprobes. For unintentionally-doped (UID) chemical vapor deposition (CVD) diamond, deep levels with activation energies of 0.35 eV and 0.43 eV were detected which correspond to the activation energy of boron acceptors in diamond. The results suggested that alpha particle and heavy ion induced QTS techniques are the promising candidate for in-situ investigation of deep levels in high-resistivity semiconductors.

  4. 78 FR 11818 - Diamond Sawblades and Parts Thereof From the Republic of Korea: Final Results of Antidumping Duty...

    Science.gov (United States)

    2013-02-20

    ... or Yasmin Nair, AD/ CVD Operations, Office 1, Import Administration, International Trade... administrative review to address Petitioner's fraud allegations.\\3\\ \\2\\ See Diamond Sawblades and Parts Thereof... (Final Decision Memorandum), which is hereby adopted by this notice, at Comment. Fraud Allegations We...

  5. Fabrication of diamond shells

    Energy Technology Data Exchange (ETDEWEB)

    Hamza, Alex V.; Biener, Juergen; Wild, Christoph; Woerner, Eckhard

    2016-11-01

    A novel method for fabricating diamond shells is introduced. The fabrication of such shells is a multi-step process, which involves diamond chemical vapor deposition on predetermined mandrels followed by polishing, microfabrication of holes, and removal of the mandrel by an etch process. The resultant shells of the present invention can be configured with a surface roughness at the nanometer level (e.g., on the order of down to about 10 nm RMS) on a mm length scale, and exhibit excellent hardness/strength, and good transparency in the both the infra-red and visible. Specifically, a novel process is disclosed herein, which allows coating of spherical substrates with optical-quality diamond films or nanocrystalline diamond films.

  6. Functionalized diamond nanoparticles

    KAUST Repository

    Beaujuge, Pierre M.

    2014-10-21

    A diamond nanoparticle can be functionalized with a substituted dienophile under ambient conditions, and in the absence of catalysts or additional reagents. The functionalization is thought to proceed through an addition reaction.

  7. Diamond nanobeam waveguide optomechanics

    CERN Document Server

    Khanaliloo, Behzad; Hryciw, Aaron C; Lake, David P; Kaviani, Hamidreza; Barclay, Paul E

    2015-01-01

    Optomechanical devices sensitively transduce and actuate motion of nanomechanical structures using light, and are central to many recent fundamental studies and technological advances. Single--crystal diamond promises to improve the performance of optomechanical devices, while also providing opportunities to interface nanomechanics with diamond color center spins and related quantum technologies. Here we demonstrate measurement of diamond nanobeam resonators with a sensitivity of 9.5 fm/Hz^0.5 and bandwidth >120 nm through dissipative waveguide--optomechanical coupling. Nanobeams are fabricated from bulk single--crystal diamond using a scalable quasi--isotropic oxygen plasma undercut etching process, and support mechanical resonances with quality factor of 2.5 x 10^5 at room temperature, and 7.2 x 10^5 in cryogenic conditions (5K). Mechanical self--oscillations, resulting from interplay between optomechanical coupling and the photothermal response of nanobeams in a buckled state, are observed with amplitude e...

  8. Quantum engineering: Diamond envy

    Science.gov (United States)

    Nunn, Joshua

    2013-03-01

    Nitrogen atoms trapped tens of nanometres apart in diamond can now be linked by quantum entanglement. This ability to produce and control entanglement in solid systems could enable powerful quantum computers.

  9. Diamond dipole active antenna

    OpenAIRE

    Bubnov, Igor N.; Falkovych, I. S.; Gridin, A. A.; Stanislavsky, A. A.; Reznik, A. P.

    2015-01-01

    Advantages of the diamond dipole antenna as an active antenna are presented. Such an antenna is like an inverted bow-tie antenna, but the former has some advantages over the ordinary bow-tie antenna. It is shown that the diamond dipole antenna may be an effective element of a new antenna array for low-frequency radio astronomy as well as a communication antenna.

  10. Diamond Detectors for the TOTEM Timing Upgrade

    CERN Document Server

    Antchev, G.; The TOTEM collaboration; Atanassov, I.; Avati, V.; Baechler, J.; Berardi, V.; Berretti, M.; Bossini, E.; Bottigli, U.;; Bozzo, M.; Broulim, P.; Buzzo, A.; Cafagna, F.S.; Campanella, C.E.; Catanesi, M.G.; Csanad, M.; Csorgo, T.; Deile, M.; De Leonardis, F.; D'Orazio, A.; Doubek, M.; Eggert, K.; Eremin, V.; Ferro, F.; Fiergolski, A.; Garcia, F.; Georgiev, V.; Giani, S.; Grzanka, L.; Guaragnella, C.; Hammerbauer, J.; Heino, J.; Hilden, T.; Karev, A.; Kavspar, J.; Kopal, J.; Kosinski, J.; Kundrat, V.; Lami, S.; Latino, G.; Lauhakangas, R.; Linhart, R.; Lokajivcek, M.V.; Losurdo, L; Lo Vetere, M.; Lucas-Rodriguez, F.; Lucsanyi, D.; Macri, M.; Mercadante, A.; Minafra, N.; Minutoli, S.; Naaranoja, T.; Nemes, F.; Niewiadomski, H.; Novak, T.; Oliveri, E.; Oljemark, F.; Oriunno, M.; Osterberg, K.; Palazzi, P.; Palocko, L.; Passaro, V.; Peroutka, Z.; Petruzzelli, V.; Politi, T.; Prochazka, J.; Prudenzano, F.; Quinto, M.; Radermacher, E.; Radicioni, E.; Ravotti, F.; Robutti, E.; Royon, C.; Ruggiero, G.; Saarikko, H.; Scribano, A.; Smajek, J.; Snoeys, W.; Sodzawiczny, T.; Sziklai, J.; Taylor, C.; Turini, N.; Vacek, V.; Welti, J.; Wyszkowski, P; Zielinski, K

    2016-01-01

    This paper describes the design and the performance of the timing detector developed by the TOTEM Collaboration for the Roman Pots (RPs) to measure the Time-Of-Flight (TOF) of the protons produced in central diffractive interactions at the LHC. The measurement of the TOF of the protons allows the determination of the longitudinal position of the proton interaction vertex and its association with one of the vertices reconstructed by the CMS detectors. The TOF detector is based on single crystal Chemical Vapor Deposition (scCVD) diamond plates and is designed to measure the protons’ TOF with about 50 ps time precision. This upgrade to the TOTEM apparatus will be used in the LHC run 2 and will tag the central diffractive events up to an interaction pileup of about 1. A dedicated fast and low noise electronics for the signal amplification has been developed. The digitization of the diamond signal is performed sampling the waveform. After introducing the physics studies that will most profit from the addition of...

  11. Advanced laser diagnostics for diamond deposition research

    Energy Technology Data Exchange (ETDEWEB)

    Kruger, C.H.; Owano, T.G.; Wahl, E.H. [Stanford Univ., CA (United States)

    1995-12-31

    Chemical Vapor Deposition (CVD) using thermal plasmas is attractive for diamond synthesis applications due to the inherently high reactant densities and throughput, but the associated high gas-phase collision rates in the boundary layer above the substrate produce steep thermal and species gradients which can drive the complex plasma chemistry away from optimal conditions. To understand and control these environments, accurate measurements of temperature and species concentrations within the reacting boundary layer are needed. This is challenging in atmospheric pressure reactors due to the highly luminous environment, steep thermal and species gradients, and small spatial scales. The applicability of degenerate four-wave mixing (DFWM) as a spectroscopic probe of atmospheric pressure reacting plasmas has been investigated. This powerful, nonlinear technique has been applied to the measurement of temperature and radical species concentrations in the boundary layer of a diamond growth substrate immersed in a flowing atmospheric pressure plasma. In-situ measurements of CH and C{sub 2} radicals have been performed to determine spatially resolved profiles of vibrational temperature, rotational temperature, and species concentration. Results of these measurements are compared with the predictions of a detailed numerical simulation.

  12. Lipids, atherosclerosis and CVD risk: is CRP an innocent bystander?

    DEFF Research Database (Denmark)

    Nordestgaard, B G; Zacho, J

    2009-01-01

    exclude that genetically elevated CRP cause CVD. CONCLUSION: These data suggest that elevated CRP per se does not cause CVD; however, inflammation per se possibly contributes to CVD. Elevated CRP levels more likely is a marker for the extent of atherosclerosis or for the inflammatory activity...

  13. Performance of detectors using a diamond sensors at the LHC and CMS

    CERN Document Server

    Hempel, M; Dabrowski, A E; Lange, W; Lohmann, W; Novgorodova, O; Odell, N J; Stickland, D P; Griesmayer, E

    2013-01-01

    Diamond detectors are used as beam loss and luminos- ity monitors for CMS and LHC. A time resolution in the nanosecond range allows to detect beam losses and lumi- nosities of single bunches. The radiation hardness and neg- ligible temperature dependence allow the usage of diamond sensors in high radiation fields without cooling. Two differ- ent diamond detector types are installed at LHC and CMS. One is based on pcCVD (polycrystalline chemical vapor deposition) diamonds and installed at different locations in the LHC tunnel for beam loss monitoring. Measurements of these detectors are used to perform a bunch-by-bunch beam loss analysis. They allow to disentangle the origin of beam losses. The second type uses scCVD (single crystal chemical vapor deposition) diamonds and is located inside CMS for van-der-Meer scan, beam halo and online lumi- nosity monitoring and around the LHC tunnel for beam loss observation. Results on the performance of these detectors will be presented and examples of the use for analyzi...

  14. Study of nitrogen doping behavior in diamond film

    Institute of Scientific and Technical Information of China (English)

    LI Ming-ji; YANG Bao-he; SUN Da-zhi; JIN Zeng-sun

    2008-01-01

    Nitrogen-doped diamond films have been synthesized by EA-CVD (electron assisted chemical vapor deposition) technique.The quality and nitrogen impurity states of the diamond films are characterized by SEM, raman spectroscopy, XPS and EPRspectroscopy, respectively. The results show that the morphology changes from well-defined facets to cauliflower-like structures,the content of amorphous carbon increases and the quality drops with increasing the nitrogen flow rate. Furthermore, in thefilms, it can be observed that nitrogen impurity exists in the forms of Ns0, [N-V]0 and [N-V]-1. The contents of [N-V]0 and[N-V]-1 are lower when the nitrogen flow rate is relatively high, and the concentration of Ns0 varies from 15 ppm to 483 ppm.

  15. Improvement on Diamond Nucleation Treated by Pulsed Arc Discharge Plasma

    Institute of Scientific and Technical Information of China (English)

    马志斌; 万军; 汪建华; 张文文

    2004-01-01

    A technique of improvement on diamond nucleation based on pulsed arc discharge plasma at atmospheric pressure was developed. The pulsed arc discharge was induced respectively by nitrogen, argon and methanol gas. After the arc plasma pretreatment, a nucleation density higher than 1010 cm-2 may be obtained subsequently in chemical vapor deposition (CVD) on a mirror-polished silicon substrate without any other mechanical treatment. The effects of the arc discharge plasma on the diamond nucleation were investigated by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (IR) and Raman spectroscopy. The enhancement of nucleation is postulated to be a result of the formation of carbonlike phase materials or nitrogenation on the substrate surface without surface defect produced by arc discharge.

  16. Diamond Pixel Modules and the ATLAS Beam Conditions Monitor

    CERN Document Server

    Dobos, D

    2011-01-01

    The ATLAS Beam Conditions Monitor’s (BCM) main purpose is to protect the experiments silicon tracker from beam incidents. In total 16 1x1 cm^2 500 um thick diamond pCVD sensors are used in eight positions around the LHC interaction point. They perform time difference measurements with sub nanosecond resolution to distinguish between particles from a collision and spray particles from a beam incident; an abundance of the latter can lead the BCM to provoke an abort of LHC beam. The BCM diamond detector modules, their readout system and the algorithms used to detect beam incidents are described. Results of the BCM operation with circulating LHC beams and it’s commissioning with first LHC collisions are reported.

  17. Influence of surface properties on the quantum photoyield of diamond photocathodes

    Energy Technology Data Exchange (ETDEWEB)

    Foord, J.S.; Wang, J.; Lau, C.H.; Hiramatsu, M.; Vickers, J. [Oxford Univ. (United Kingdom). Physical and Theoretical Chemistry Lab.; Jackman, R.B. [University Coll., London (United Kingdom). Dept. of Electrical and Electronic Engineering

    2001-07-23

    The quantum efficiency and chemical stability of CVD diamond photocathodes has been examined. As-grown or microwave plasma hydrogenated boron-doped diamond films display a quantum photoyield of approximately 0.05% at 190 nm, which degrades gradually as the material is left in ambient atmosphere, due to slow oxidation. Rapid degradation in performance occurs when exposed to atomic or electronically excited oxygen. X-ray photoelectron spectroscopy shows that the yield drops close to zero at around monolayer oxygen coverage, and that the main oxygen species on the surface is hydroxyl or isolated ether linkages. (orig.)

  18. Diamond planar refractive lenses for third- and fourth-generation X-ray sources.

    Science.gov (United States)

    Nöhammer, Bernd; Hoszowska, Joanna; Freund, Andreas K; David, Christian

    2003-03-01

    The fabrication and testing of planar refractive hard X-ray lenses made from bulk CVD diamond substrates is reported. The lens structures were generated by electron-beam lithography and transferred by reactive-ion etching into the diamond. Various lens designs were fabricated and tested at 12.4 and 17.5 keV photon energy. Efficiencies of up to 71% and gains of up to 26 were achieved. A line focus of 3.2 micro m (FWHM) was measured. These lenses should be able to withstand the extreme flux densities expected at the planned fourth-generation X-ray sources.

  19. Deposition and Coating Properties on CVD Tungsten

    Institute of Scientific and Technical Information of China (English)

    DU Ji-hong; LI Zheng-xiang; LIU Gao-jian; ZHOU Hui-Huang; CHUN liang

    2004-01-01

    Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.

  20. High-temperature Infrared Transmission of Free-standing Diamond Films

    Directory of Open Access Journals (Sweden)

    HEI Li-fu

    2017-02-01

    Full Text Available The combination of low absorption and extreme mechanical and thermal properties make diamond a compelling choice for some more extreme far infrared (8-12 μm window applications. The optical properties of CVD diamond at elevated temperatures are critical to many of these extreme applications. The infrared transmission of free-standing diamond films prepared by DC arc plasma jet were studied at temperature varied conditions. The surface morphology, structure feature and infrared optical properties of diamond films were tested by optical microscope, X-ray diffraction, laser Raman and Fourier-transform infrared spectroscopy. The results show that the average transmittance for 8-12μm is decreased from 65.95% at 27℃ to 52.5% at 500℃,and the transmittance drop is in three stages. Corresponding to the drop of transmittance with the temperature, diamond film absorption coefficient increases with the rise of temperature. The influence of the change of surface state of diamond films on the optical properties of diamond films is significantly greater than the influence on the internal structure.

  1. Clinical studies of optimised single crystal and polycrystalline diamonds for radiotherapy dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Descamps, C. [CEA-LIST (Recherche Technologique)/DETECS/SSTM/LCD, CEA/Saclay, Gif-sur-Yvette (France)], E-mail: cdescamps23@yahoo.fr; Tromson, D.; Tranchant, N. [CEA-LIST (Recherche Technologique)/DETECS/SSTM/LCD, CEA/Saclay, Gif-sur-Yvette (France); Isambert, A.; Bridier, A. [Institut Gustave Roussy, Villejuif (France); De Angelis, C.; Onori, S. [Dipartimento di Tecnologie e Salute, Istituto Superiore di Sanita, Roma (Italy); Bucciolini, M. [Dipartimento di Fisiopatologia dell' Universita, Firenze (Italy); Bergonzo, P. [CEA-LIST (Recherche Technologique)/DETECS/SSTM/LCD, CEA/Saclay, Gif-sur-Yvette (France)

    2008-02-15

    Natural diamond based ionisation chambers commercialised by PTW are used in several hospitals, and their dosimetric properties have been reported in many papers. Nevertheless their high costs and long delivery times are strong drawbacks. Advancements in the growth of synthetic diamonds offer new possibilities. This paper presents the dosimetric analysis in terms of stability and repeatability of the signal, background signal, detector response dynamics, linearity of the signal with the absorbed dose and dose rate dependence of synthetic optimised polycrystalline and single crystal diamonds. Both were elaborated at the CEA-LIST using the chemical vapour deposition (CVD) growth technique. The first dosimetric evaluation of single crystal diamond detector, reported here, shows a repeatability better than 0.1%, a good sensitivity around 70 nC/Gy compared to 3 nC/Gy for optimised polycrystalline diamond, very fast response with rise time around 1 s. Moreover, the signal linearity vs absorbed dose and energy dependence are very satisfactory. This preliminary dosimetric study with medical linear accelerators proves that diamond, and more precisely synthetic single crystal diamond, appears as a good alternative to air ionisation chambers for quality beam control and could be a good candidate for intensity modulated radiation therapy (IMRT) beams dosimetry.

  2. Response of diamond detector sandwich to 14 MeV neutrons

    CERN Document Server

    Osipenko, M; Ricco, G; Caiffi, B; Pompili, F; Pillon, M; Verona-Rinati, G; Cardarelli, R

    2015-01-01

    In this paper we present the measurement of the response of 50 $\\mu$m thin diamond detectors to 14 MeV neutrons. Such neutrons are produced in fusion reactors and are of particular interest for ITER neutron diagnostics. Among semiconductor detectors diamond has properties most appropriate for harsh radiation and temperature conditions of a fusion reactor. However, 300-500 $\\mu$m thick diamond detectors suffer significant radiation damage already at neutron fluences of the order of $10^{14}$ n/cm$^2$. It is expected that a 50 $\\mu$m thick diamond will withstand a fluence of $>10^{16}$ n/cm$^2$. We tested two 50 $\\mu$m thick single crystal CVD diamonds, stacked to form a ``sandwich'' detector for coincidence measurements. The detector measured the conversion of 14 MeV neutrons, impinging on one diamond, into $\\alpha$ particles which were detected in the second diamond in coincidence with nuclear recoil. For $^{12}C(n,\\alpha)^{9}Be$ reaction the total energy deposited in the detector gives access to the initial ...

  3. Study of the effects of focused high-energy boron ion implantation in diamond

    Science.gov (United States)

    Ynsa, M. D.; Agulló-Rueda, F.; Gordillo, N.; Maira, A.; Moreno-Cerrada, D.; Ramos, M. A.

    2017-08-01

    Boron-doped diamond is a material with a great technological and industrial interest because of its exceptional chemical, physical and structural properties. At modest boron concentrations, insulating diamond becomes a p-type semiconductor and at higher concentrations a superconducting metal at low temperature. The most conventional preparation method used so far, has been the homogeneous incorporation of boron doping during the diamond synthesis carried out either with high-pressure sintering of crystals or by chemical vapour deposition (CVD) of films. With these methods, high boron concentration can be included without distorting significantly the diamond crystalline lattice. However, it is complicated to manufacture boron-doped microstructures. A promising alternative to produce such microstructures could be the implantation of focused high-energy boron ions, although boron fluences are limited by the damage produced in diamond. In this work, the effect of focused high-energy boron ion implantation in single crystals of diamond is studied under different irradiation fluences and conditions. Micro-Raman spectra of the sample were measured before and after annealing at 1000 °C as a function of irradiation fluence, for both superficial and buried boron implantation, to assess the changes in the diamond lattice by the creation of vacancies and defects and their degree of recovery after annealing.

  4. Pixel diamond detectors for excimer laser beam diagnostics

    Science.gov (United States)

    Girolami, M.; Allegrini, P.; Conte, G.; Salvatori, S.

    2011-05-01

    Laser beam profiling technology in the UV spectrum of light is evolving with the increase of excimer lasers and lamps applications, that span from lithography for VLSI circuits to eye surgery. The development of a beam-profiler, able to capture the excimer laser single pulse and process the acquired pixel current signals in the time period between each pulse, is mandatory for such applications. 1D and 2D array detectors have been realized on polycrystalline CVD diamond specimens. The fast diamond photoresponse, in the ns time regime, suggests the suitability of such devices for fine tuning feedback of high-power pulsed-laser cavities, whereas solar-blindness guarantees high performance in UV beam diagnostics, also under high intensity background illumination. Offering unique properties in terms of thermal conductivity and visible-light transparency, diamond represents one of the most suitable candidate for the detection of high-power UV laser emission. The relatively high resistivity of diamond in the dark has allowed the fabrication of photoconductive vertical pixel-detectors. A semitransparent light-receiving back-side contact has been used for detector biasing. Each pixel signal has been conditioned by a multi-channel read-out electronics made up of a high-sensitive integrator and a Σ-Δ A/D converter. The 500 μs conversion time has allowed a data acquisition rate up to 2 kSPS (Sample Per Second).

  5. Improving nanocrystalline diamond coatings for micro end mills

    Science.gov (United States)

    Heaney, Patrick J.

    A new method is presented for coating 300 mum diameter tungsten carbide (WC) micro end mills with diamond using a hot filament chemical vapor deposition (HF-CVD) method. This method has been developed to create uniform, conformal and continuous diamond coatings. Initial work is shown to prove the feasibility and concept of the project. This was the first work known to coat and evaluate the machining performance WC micro end mills. The performance of uncoated and coated micro end mills was evaluated by dry machining channels in 6061-T6 aluminum. The test results showed a 75% and 90% decrease in both cutting and trust forces for machining, respectfully. The coated tools produced a more predictable surface finish with no burring. These improved results are due to the superior tribological properties of diamond against aluminum. Initial results indicated severe problems with coating delamination causing complete tool failure. After proving the initial concept, new methods for optimizing the coating and improving performance were studied. Each optimization step is monitored through surface analysis techniques to monitor changes in coating morphology and diamond quality. Nucleation density was increased by improving the seed method, using ultra dispersed diamond (UDD) seed. The increase in nucleation density allowed the synthesis of coatings as thin as 60 nm. The adhesion of the coating to the tool was improved through carbon ion implantation (CII). CII is a different surface preparation technique that deactivates the effect of Co, while not weakening the tool. CII also creates a great nucleation layer which diamond can directly grow from, allowing the diamond coating to chemically bond to the substrate improving adhesion and eliminating the need for a seed layer. These thin coatings were shown to be of high quality sp3 trigonaly bonded diamond that resulted in lower machining forces with less delamination. The 90% reduction in machining forces that thin conformal

  6. Diamond electronic properties and applications

    CERN Document Server

    Kania, Don R

    1995-01-01

    The use of diamond in electronic applications is not a new idea, but limitations in size and control of properties restricted the use of diamond to a few specialised applications. The vapour-phase synthesis of diamond, however, has facilitated serious interest in the development of diamond-based electronic devices. The process allows diamond films to be laid down over large areas. Both intrinsic and doped diamond films have a unique combination of extreme properties for high speed, high power and high temperature applications. The eleven chapters in Diamond: Electronic Properties and Applications, written by the world's foremost experts on the subject, give a complete characterisation of the material, in both intrinsic and doped forms, explain how to grow it for electronic applications, how to use the grown material, and a description of both passive and active devices in which it has been used with success. Diamond: Electronic Properties and Applications is a compendium of the available literature on the sub...

  7. Diamond pixel modules

    CERN Document Server

    Gan, K K; Robichaud, A; Potenza, R; Kuleshov, S; Kagan, H; Kass, R; Wermes, N; Dulinski, W; Eremin, V; Smith, S; Sopko, B; Olivero, P; Gorisek, A; Chren, D; Kramberger, G; Schnetzer, S; Weilhammer, P; Martemyanov, A; Hugging, F; Pernegger, H; Lagomarsino, S; Manfredotti, C; Mishina, M; Trischuk, W; Dobos, D; Cindro, V; Belyaev, V; Duris, J; Claus, G; Wallny, R; Furgeri, A; Tuve, C; Goldstein, J; Sciortino, S; Sutera, C; Asner, D; Mikuz, M; Lo Giudice, A; Velthuis, J; Hits, D; Griesmayer, E; Oakham, G; Frais-Kolbl, H; Bellini, V; D'Alessandro, R; Cristinziani, M; Barbero, M; Schaffner, D; Costa, S; Goffe, M; La Rosa, A; Bruzzi, M; Schreiner, T; de Boer, W; Parrini, G; Roe, S; Randrianarivony, K; Dolenc, I; Moss, J; Brom, J M; Golubev, A; Mathes, M; Eusebi, R; Grigoriev, E; Tsung, J W; Mueller, S; Mandic, I; Stone, R; Menichelli, D

    2011-01-01

    With the commissioning of the LHC in 2010 and upgrades expected in 2015, ATLAS and CMS are planning to upgrade their innermost tracking layers with radiation hard technologies. Chemical Vapor Deposition diamond has been used extensively in beam conditions monitors as the innermost detectors in the highest radiation areas of BaBar, Belle, CDF and all LHC experiments. This material is now being considered as a sensor material for use very close to the interaction region where the most extreme radiation conditions exist Recently the RD42 collaboration constructed, irradiated and tested polycrystalline and single-crystal chemical vapor deposition diamond sensors to the highest fluences expected at the super-LHC. We present beam test results of chemical vapor deposition diamond up to fluences of 1.8 x 10(16) protons/cm(2) illustrating that both polycrystalline and single-crystal chemical vapor deposition diamonds follow a single damage curve. We also present beam test results of irradiated complete diamond pixel m...

  8. Heteroepitaxial diamond growth

    Science.gov (United States)

    Markunas, R. J.; Rudder, R. A.; Posthill, J. B.; Thomas, R. E.; Hudson, G.

    1994-02-01

    Technical highlights from 1993 include the following: Growth Chemistries: A clear correlation was observed between ionization potential of feedstock gasses and critical power necessary for inductive coupling of the plasma and consequent diamond growth. Substrate preparation and epitaxial film quality: Ion-implantation of C and O has been coupled with either electrochemical etching or acid cleaning for surface preparation prior to homoepitaxial growth. Reactor modifications: Key improvements were made to the RF reactor to allow for long growths to consolidate substrates. Liquid mass flow controllers were added to precisely meter both the water and selected alcohol. Ion-implantation and lift off: Lift off of diamond platelets has been achieved with two processes. Ion-implantation of either C or O followed by annealing and implantation of either C or O followed by water based electrolysis. Diamond characterization: Development of novel detect characterization techniques: (1) Etch delineation of defects by exposure to propane torch flame. (2) Hydrogen plasma exposure to enhance secondary electron emission and provide non-topographical defect contrast. Acetylene will react at room temperature with sites created by partial desorption of oxygen from the (100) diamond surface. Thermal desorption measurements give an apparent activation energy for CO desorption from diamond (100) of 45 kcal/mol. Quantum chemical calculations indicate an activation energy of 38 kcal/mol for CO desorption. Ab initio calculations on (100) surfaces indicates that oxygen adsorbed at one dimer site has an effect on the dimerization of an adjacent site.

  9. Friction and Wear Performance of Boron Doped, Undoped Microcrystalline and Fine Grained Composite Diamond Films

    Institute of Scientific and Technical Information of China (English)

    WANG Xinchang; WANG Liang; SHEN Bin; SUN Fanghong

    2015-01-01

    Chemical vapor deposition (CVD) diamond films have attracted more attentions due to their excellent mechanical properties. Whereas as-fabricated traditional diamond films in the previous studies don’t have enough adhesion or surface smoothness, which seriously impact their friction and wear performance, and thus limit their applications under extremely harsh conditions. A boron doped, undoped microcrystalline and fine grained composite diamond (BD-UM-FGCD) film is fabricated by a three-step method adopting hot filament CVD (HFCVD) method in the present study, presenting outstanding comprehensive performance, including the good adhesion between the substrate and the underlying boron doped diamond (BDD) layer, the extremely high hardness of the middle undoped microcrystalline diamond (UMCD) layer, as well as the low surface roughness and favorable polished convenience of the surface fine grained diamond (FGD) layer. The friction and wear behavior of this composite film sliding against low-carbon steel and silicon nitride balls are studied on a ball-on-plate rotational friction tester. Besides, its wear rate is further evaluated under a severer condition using an inner-hole polishing apparatus, with low-carbon steel wire as the counterpart. The test results show that the BD-UM-FGCD film performs very small friction coefficient and great friction behavior owing to its high surface smoothness, and meanwhile it also has excellent wear resistance because of the relatively high hardness of the surface FGD film and the extremely high hardness of the middle UMCD film. Moreover, under the industrial conditions for producing low-carbon steel wires, this composite film can sufficiently prolong the working lifetime of the drawing dies and improve their application effects. This research develops a novel composite diamond films owning great comprehensive properties, which have great potentials as protecting coatings on working surfaces of the wear-resistant and anti

  10. Friction and wear performance of boron doped, undoped microcrystalline and fine grained composite diamond films

    Science.gov (United States)

    Wang, Xinchang; Wang, Liang; Shen, Bin; Sun, Fanghong

    2015-01-01

    Chemical vapor deposition (CVD) diamond films have attracted more attentions due to their excellent mechanical properties. Whereas as-fabricated traditional diamond films in the previous studies don't have enough adhesion or surface smoothness, which seriously impact their friction and wear performance, and thus limit their applications under extremely harsh conditions. A boron doped, undoped microcrystalline and fine grained composite diamond (BD-UM-FGCD) film is fabricated by a three-step method adopting hot filament CVD (HFCVD) method in the present study, presenting outstanding comprehensive performance, including the good adhesion between the substrate and the underlying boron doped diamond (BDD) layer, the extremely high hardness of the middle undoped microcrystalline diamond (UMCD) layer, as well as the low surface roughness and favorable polished convenience of the surface fine grained diamond (FGD) layer. The friction and wear behavior of this composite film sliding against low-carbon steel and silicon nitride balls are studied on a ball-on-plate rotational friction tester. Besides, its wear rate is further evaluated under a severer condition using an inner-hole polishing apparatus, with low-carbon steel wire as the counterpart. The test results show that the BD-UM-FGCD film performs very small friction coefficient and great friction behavior owing to its high surface smoothness, and meanwhile it also has excellent wear resistance because of the relatively high hardness of the surface FGD film and the extremely high hardness of the middle UMCD film. Moreover, under the industrial conditions for producing low-carbon steel wires, this composite film can sufficiently prolong the working lifetime of the drawing dies and improve their application effects. This research develops a novel composite diamond films owning great comprehensive properties, which have great potentials as protecting coatings on working surfaces of the wear-resistant and anti

  11. Growth and characterization of nanodiamond layers prepared using the plasma-enhanced linear antennas microwave CVD system

    Energy Technology Data Exchange (ETDEWEB)

    Fendrych, Frantisek; Taylor, Andrew; Peksa, Ladislav; Kratochvilova, Irena; Kluiber, Zdenek; Fekete, Ladislav [Institute of Physics, Academy of Sciences of the Czech Republic, v.v.i, Na Slovance 2, CZ-18221 Prague 8 (Czech Republic); Vlcek, Jan [Department of Physics and Measurement, Institute of Chemical Technology Prague, Technicka 5, CZ-16628 Prague 6 (Czech Republic); Rezacova, Vladimira; Petrak, Vaclav [Faculty of Biomedical Engineering, Czech Technical University, Sitna 3105, CZ-27201 Kladno 2 (Czech Republic); Liehr, Michael [Leybold Optics Dresden GmbH, Zur Wetterwarte 50, D-01109 Dresden (Germany); Nesladek, Milos, E-mail: fendrych@fzu.c [IMOMEC division, IMEC, Institute for Materials Research, University Hasselt, Wetenschapspark 1, B-3590 Diepenbeek (Belgium)

    2010-09-22

    Industrial applications of plasma-enhanced chemical vapour deposition (CVD) diamond grown on large area substrates, 3D shapes, at low substrate temperatures and on standard engineering substrate materials require novel plasma concepts. Based on the pioneering work of the group at AIST in Japan, the high-density coaxial delivery type of plasmas has been explored (Tsugawa et al 2006 New Diamond Front. Carbon Technol. 16 337-46). However, an important challenge is to obtain commercially interesting growth rates at very low substrate temperatures. In this work we introduce the concept of novel linear antenna sources, designed at Leybold Optics Dresden, using high-frequency pulsed MW discharge with a high plasma density. This type of pulse discharges leads to the preparation of nanocrystalline diamond (NCD) thin films, compared with ultra-NCD thin films prepared in (Tsugawa et al 2006 New Diamond Front. Carbon Technol. 16 337-46). We present optical emission spectroscopy data for the CH{sub 4}-CO{sub 2}-H{sub 2} gas chemistry and we discuss the basic properties of the NCD films grown.

  12. Diamond Measuring Machine

    Energy Technology Data Exchange (ETDEWEB)

    Krstulic, J.F.

    2000-01-27

    The fundamental goal of this project was to develop additional capabilities to the diamond measuring prototype, work out technical difficulties associated with the original device, and perform automated measurements which are accurate and repeatable. For this project, FM and T was responsible for the overall system design, edge extraction, and defect extraction and identification. AccuGem provided a lab and computer equipment in Lawrence, 3D modeling, industry expertise, and sets of diamonds for testing. The system executive software which controls stone positioning, lighting, focusing, report generation, and data acquisition was written in Microsoft Visual Basic 6, while data analysis and modeling were compiled in C/C++ DLLs. All scanning parameters and extracted data are stored in a central database and available for automated analysis and reporting. The Phase 1 study showed that data can be extracted and measured from diamond scans, but most of the information had to be manually extracted. In this Phase 2 project, all data required for geometric modeling and defect identification were automatically extracted and passed to a 3D modeling module for analysis. Algorithms were developed which automatically adjusted both light levels and stone focus positioning for each diamond-under-test. After a diamond is analyzed and measurements are completed, a report is printed for the customer which shows carat weight, summarizes stone geometry information, lists defects and their size, displays a picture of the diamond, and shows a plot of defects on a top view drawing of the stone. Initial emphasis of defect extraction was on identification of feathers, pinpoints, and crystals. Defects were plotted color-coded by industry standards for inclusions (red), blemishes (green), and unknown defects (blue). Diamonds with a wide variety of cut quality, size, and number of defects were tested in the machine. Edge extraction, defect extraction, and modeling code were tested for

  13. Modeling for CVD of Solid Oxide Electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Starr, T.L.

    2002-09-18

    Because of its low thermal conductivity, high thermal expansion and high oxygen ion conductivity yttria-stabilized zirconia (YSZ) is the material of choice for high temperature electrolyte applications. Current coating fabrication methods have their drawbacks, however. Air plasma spray (APS) is a relatively low-cost process and is suitable for large and relatively complex shapes. it is difficult to produce uniform, relatively thin coatings with this process, however, and the coatings do not exhibit the columnar microstructure that is needed for reliable, long-term performance. The electron-beam physical vapor deposition (EB-PVD) process does produce the desirable microstructure, however, the capital cost of these systems is very high and the line-of-sight nature of the process limits coating uniformity and the ability to coat large and complex shapes. The chemical vapor deposition (CVD) process also produces the desirable columnar microstructure and--under proper conditions--can produce uniform coatings over complex shapes. CVD has been used for many materials but is relatively undeveloped for oxides, in general, and for zirconia, in particular. The overall goal of this project--a joint effort of the University of Louisville and Oak Ridge National Laboratory (ORNL)--is to develop the YSZ CVD process for high temperature electrolyte applications. This report describes the modeling effort at the University of Louisville, which supports the experimental work at ORNL. Early work on CVD of zirconia and yttria used metal chlorides, which react with water vapor to form solid oxide. Because of this rapid gas-phase reaction the water generally is formed in-situ using the reverse water-gas-shift reaction or a microwave plasma. Even with these arrangements gas-phase nucleation and powder formation are problems when using these precursors. Recent efforts on CVD of zirconia and YSZ have focused on use of metal-organic precursors (MOCVD). These are more stable in the gas

  14. Field emission from carbon films deposited by VHF CVD on difference substrates

    Energy Technology Data Exchange (ETDEWEB)

    Abramov, A A; Andronov, A N; Felter, T E; Ioffe, A F; Kosarev, A I; Shotov, M V; Vinogradov, A J

    1999-04-01

    As previously demonstrated, non-diamond carbon (NDC) films deposited at low temperatures 200-300 C on silicon tips reduced the threshold of field emission. In this paper we will present the results of the study of field emission from flat NDC films prepared by VHF CVD. Emission measurements were performed in a diode configuration at approximately 10{sup {minus}10} Torr. NDC films were deposited on ceramic and on c-Si substrates sputter coated with layers of Ti, Cu, Ni and Pt. The back contact material influences the emission characteristics but not as a direct correlation to work function. A model of field emission from metal-NDC film structures will be discussed.

  15. Test of a Diamond Detector Using Unbunched Beam Halo Particles

    CERN Document Server

    Dehning, B; Pernegger, H; Dobos, D; Frais-Kolbl, H; Griesmayer, E

    2010-01-01

    A pCVD diamond detector has been evaluated as a beam loss monitor for future applications in the LHC accelerator. The test monitor was mounted in the SPS BA5 downstream of a LHC collimator during the LHC beam set-up. CVD diamond particle detectors are already in use in the CERN experiments ATLAS, CMS, LHCb and Alice. This is a proven technology with high radiation tolerance and very fast signal read-out. It can be used for single-particle detection, as well as for measuring particle cascades, for timing measurements on the nanosecond scale and for beam protection systems. Despite the read-out being made through 250 m of CK50 cable, the tests have shown a very good signal-to-noise ratio of 6.8, an excellent double-pulse resolution of less than 5 ns and a high dynamic range of 1:350 MIP particles. The efficiency of particle detection is practically 100% for charged particles.

  16. Direct coating adherent diamond films on Fe-based alloy substrate: the roles of Al, Cr in enhancing interfacial adhesion and promoting diamond growth.

    Science.gov (United States)

    Li, X J; He, L L; Li, Y S; Yang, Q; Hirose, A

    2013-08-14

    Direct CVD deposition of dense, continuous, and adherent diamond films on conventional Fe-based alloys has long been considered impossible. The current study demonstrates that such a deposition can be realized on Al, Cr-modified Fe-based alloy substrate (FeAl or FeCrAl). To clarify the fundamental mechanism of Al, Cr in promoting diamond growth and enhancing interfacial adhesion, fine structure and chemical analysis around the diamond film-substrate interface have been comprehensively characterized by transmission electron microscopy. An intermediate graphite layer forms on those Al-free substrates such as pure Fe and FeCr, which significantly deteriorates the interfacial adhesion of diamond. In contrast, such a graphite layer is absent on the FeAl and FeCrAl substrates, whereas a very thin Al-rich amorphous oxide sublayer is always identified between the diamond film and substrate interface. These comparative results indicate that the Al-rich interfacial oxide layer acts as an effective barrier to prevent the formation of graphite phase and consequently enhance diamond growth and adhesion. The adhesion of diamond film formed on FeCrAl is especially superior to that formed on FeAl substrate. This can be further attributed to a synergetic effect including the reduced fraction of Al and the decreased substrate thermal-expansion coefficient on FeCrAl in comparison with FeAl, and a mechanical interlocking effect due to the formation of interfacial chromium carbides. Accordingly, a mechanism model is proposed to account for the different interfacial adhesion of diamond grown on the various Fe-based substrates.

  17. Test beam & time resolution analysis for UFSD and CVD diamond detectors

    CERN Document Server

    Scali, Stefano

    2017-01-01

    The ever-increasing luminosity in particle physics, aimed at seeking new phenomena, has led to the need for radiation-hard detectors with a remarkable time resolution. To reach the goal several tests and data analysis has been performed but further development is still required. During my internship I have participated to the test of new sensors. After an introduction to the theoretical framework this report describes the data taking procedure using SPS beam at the H8 site in Prevessin. The second part describes the data analysis and extrapolation of the time resolution for many boards.

  18. FIB and CVD Fabrication of Carbon Nanostructures on Diamond and Quartz Substrates

    Science.gov (United States)

    2011-03-29

    Earth sciences", Institute of Mineralogy and Crystallography, University of Vienna, Austria, March 3, 2008. 12. V. Kumar, "Polymeric solar cells ...nanowires in the 500 m structures. (d) FIB image of the interdigital carbon nanowire structure. Overlapping area of two interintruding nanowire combs...structures of another type were made as two interdigital comb arrays penetrating one into another with an overlapping area of 1010 m 2 (Fig. 1.23d). The

  19. Biofunctionalization of diamond microelectrodes

    Energy Technology Data Exchange (ETDEWEB)

    Reitinger, Andreas Adam; Lud, Simon Quartus; Stutzmann, Martin; Garrido, Jose Antonio [Walter Schottky Institut, TU Muenchen (Germany); Hutter, Naima Aurelia; Richter, Gerhard; Jordan, Rainer [WACKER-Chair of Macromolecular Chemistry, TU Muenchen (Germany)

    2010-07-01

    In this work we present two main routes for the biofunctionalization of nanocrystalline diamond films, aiming at the application of diamond microelectrodes as amperometric biosensors. We report on direct covalent grafting of biomolecules on nanocrystalline diamond films via diazonium monophenyls and biphenyls as well as other linker molecules, forming self-assembled monolayers on the diamond surface. Monolayers with different functional head groups have been characterized. Patterning of the available functional groups using electron beam-induced chemical lithography allows the selective preparation of well-localized docking sites for the immobilization of biomolecules. Furthermore, polymer brushes are expected to enable novel paths for designing more advanced biosensing schemes, incorporating multifunctional groups and a higher loading capacity for biomolecules. Here, we focus on the preparation of polymer grafts by self-initiated photografting and photopolymerization. Further chemical modification of the grafted polymer brushes results in the introduction of additional functional molecules, paving the way for the incorporation of more complex molecular structures such as proteins. In a comparative study we investigate the advantages and disadvantages of both approaches.

  20. Diamond growth in mantle fluids

    Science.gov (United States)

    Bureau, Hélène; Frost, Daniel J.; Bolfan-Casanova, Nathalie; Leroy, Clémence; Esteve, Imène; Cordier, Patrick

    2016-11-01

    In the upper mantle, diamonds can potentially grow from various forms of media (solid, gas, fluid) with a range of compositions (e.g. graphite, C-O-H fluids, silicate or carbonate melts). Inclusions trapped in diamonds are one of the few diagnostic tools that can constrain diamond growth conditions in the Earth's mantle. In this study, inclusion-bearing diamonds have been synthesized to understand the growth conditions of natural diamonds in the upper mantle. Diamonds containing syngenetic inclusions were synthesized in multi-anvil presses employing starting mixtures of carbonates, and silicate compositions in the presence of pure water and saline fluids (H2O-NaCl). Experiments were performed at conditions compatible with the Earth's geotherm (7 GPa, 1300-1400 °C). Results show that within the timescale of the experiments (6 to 30 h) diamond growth occurs if water and carbonates are present in the fluid phase. Water promotes faster diamond growth (up to 14 mm/year at 1400 °C, 7 GPa, 10 g/l NaCl), which is favorable to the inclusion trapping process. At 7 GPa, temperature and fluid composition are the main factors controlling diamond growth. In these experiments, diamonds grew in the presence of two fluids: an aqueous fluid and a hydrous silicate melt. The carbon source for diamond growth must be carbonate (CO32) dissolved in the melt or carbon dioxide species in the aqueous fluid (CO2aq). The presence of NaCl affects the growth kinetics but is not a prerequisite for inclusion-bearing diamond formation. The presence of small discrete or isolated volumes of water-rich fluids is necessary to grow inclusion-bearing peridotitic, eclogitic, fibrous, cloudy and coated diamonds, and may also be involved in the growth of ultradeep, ultrahigh-pressure metamorphic diamonds.

  1. Mo-C Multilayered CVD Coatings

    Directory of Open Access Journals (Sweden)

    A. Sagalovych

    2013-12-01

    Full Text Available Production processes of multi-layered Mo-C coatings by the method of chemical vapor deposition (CVD with the use of organometallic compounds were developed. Coatings are applied on technical purpose steel DIN 1.2379 (H12F1 and DIN 1.7709 (25H2MF (ÉI10 heat-treated ball with the high class of surface roughness (> 10. The average deposition rate was 50 μm / h. The optimal conditions of deposition coatings for different technological schemas were defined. Metallographic investigations of the obtained coatings were carried out. Tribological studies of the friction and wear characteristics of sliding friction in conditions of boundary lubrication of Ï-S multilayered CVD coatings shows, that coatings have low friction coefficients (0075-0095 at loads up to 2.0 kN, showed high resistance to wear and are effective in increasing the stability of the pair for precision friction pairs of hydraulical units.

  2. Facet-dependent study of efficient growth of graphene on copper by ethanol-CVD

    Indian Academy of Sciences (India)

    Anil Kumar Singh; Anjan Kumar Gupta

    2015-12-01

    The growth of graphene by chemical vapour deposition (CVD) on copper is the most promising scalable method for high-quality graphene. The use of ethanol, an economic and safe precursor, for the fast growth of graphene on copper by a home-built CVD set-up was analysed. Full coverage of uniform single-layer graphene with high crystalline quality was found on $\\langle100\\rangle$ textured Cu foils in just 30 s. The nucleation density of graphene islands was found to be independent of facets but the island shape showed facet dependence. Diamond-like islands were observed on Cu(100) facets while random shaped islands were seen on other facets. The last observation is discussed in terms of a competition between graphene-island growth and its relaxation rate on different facets. On Cu(100) slower island growth as compared to its relaxation leads to equilibrium shapes as opposed to other facets. Further, an observed evolution in graphene contrast in electron micrographs with time on different facets was discussed in terms of oxygen diffusion between graphene and Cu.

  3. Chemical Vapour Deposition Diamond - Charge Carrier Movement at Low Temperatures and Use in Time-Critical Applications

    CERN Document Server

    Jansen, Hendrik; Pernegger, Heinz

    Diamond, a wide band gap semiconductor with exceptional electrical properties, has found its way in diverse fields of application reaching from the usage as a sensor material for beam loss monitors at particle accelerator facilities, to laser windows, to UV light sensors in space applications, e.g. for space weather forecasting. Though often used at room temperature, little is known about the charge transport in diamond towards liquid helium temperatures. In this work the method of the transient current technique is employed at temperatures between room temperature and 2 K. The temperature and electric field strength dependence of the pulse shape, the charge carrier transit time, the drift velocity, the saturation velocity, and the low-field mobility is measured in detector-grade scCVD diamond. Furthermore, the usability of diamond in time-critical applications is tested, and the main results are presented.

  4. Chemical pretreatments at surface of WC-6% Co for diamond coatings

    Institute of Scientific and Technical Information of China (English)

    刘沙; 易丹青; 余志明; 卢斌; 王建华

    2002-01-01

    The WC-6%Co(mass fraction) substrate surfaces were chemically pretreated with the two-step etching method, using Murakami reagent for 3~7min, and then an φ(HNO3)∶φ(HCl)=4∶1 solution for 1~15min. Diamond films were deposited on the substrates by a hot-filament chemical vapor deposition reactor. The results show that the Co content of the substrate surfaces can be reduced from 6% to 0.12% within the etching depth of 5~10μm, the surface roughness of the substrates is increased up to Ra=1.0μm, as well as the substrates hardness is decreased from HRA 89.5 to HRA 84.2 after the two-step etching. A slight preference towards {111} orientation can be observed from the XRD patterns and SEM micrograph of diamond film on WC-6%Co sample. The morphology of small rice-like ballas diamond was observed on the WC-6%Co substrates. A typical Raman spectrum with a sharp peak at 1332cm-1 for the diamond film indicates that the deposited films are good-quality polycrystalline diamond. The indentation testing shows that the adhesion between diamond film and the substrate after HF CVD deposition is good.

  5. Effect of temperature on the stability of diamond particles and continuous thin films by Raman imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kumaran, C. R.; Tiwari, Brajesh; Chandran, Maneesh; Bhattacharya, S. S.; Ramachandra Rao, M. S., E-mail: msrrao@iitm.ac.in [Indian Institute of Technology Madras, Nano Functional Materials Technology Centre (India)

    2013-03-15

    The stability of diamond thin films grown by hot filament CVD (HFCVD) upon thermal treatment was studied using Raman imaging. By adapting two different surface pretreatments, continuous microcrystalline diamond (MCD) thin films (grain size: 100-400 nm; cross-sectional thickness: {approx}300 nm) as well as thin film with isolated and coalesced diamond particles (particle size: 400-600 nm; cross-sectional thickness: {approx}200-300 nm) were grown. The thermal stability of isolated diamond particles and continuous MCD films annealed in air at atmospheric pressure was analyzed by Raman imaging. For Raman imaging, Raman spectra were collected over an area of 85 Multiplication-Sign 85 {mu}m using 532 nm laser (Nd:YAG) before and after thermal treatment. It was observed that the isolated diamond particles were stable for 1 h at {approx}750 Degree-Sign C, whereas for the same annealing duration, continuous MCD films grown under the same HFCVD condition were completely oxidized at 700 Degree-Sign C. From these results and analysis, the reason for the higher oxidation rates in the case of MCD and nanocrystalline diamond films is discussed.

  6. Signal and noise of Diamond Pixel Detectors at High Radiation Fluences

    CERN Document Server

    Tsung, Jieh-Wen; Hügging, Fabian; Kagan, Harris; Krüger, Hans; Wermes, Norbert

    2012-01-01

    CVD diamond is an attractive material option for LHC vertex detectors because of its strong radiation-hardness causal to its large band gap and strong lattice. In particular, pixel detectors operating close to the interaction point profit from tiny leakage currents and small pixel capacitances of diamond resulting in low noise figures when compared to silicon. On the other hand, the charge signal from traversing high energy particles is smaller in diamond than in silicon by a factor of about 2.2. Therefore, a quantitative determination of the signal-to-noise ratio (S/N) of diamond in comparison with silicon at fluences in excess of 10$^{15}$ n$_{eq}$ cm$^{-2}$, which are expected for the LHC upgrade, is important. Based on measurements of irradiated diamond sensors and the FE-I4 pixel readout chip design, we determine the signal and the noise of diamond pixel detectors irradiated with high particle fluences. To characterize the effect of the radiation damage on the materials and the signal decrease, the chang...

  7. Forty years of development in diamond tools

    Science.gov (United States)

    The growth of the diamond industry in Western Countries since the First World War is surveyed. The articles described deal specifically with the development of the industrial diamond and diamond tool sector in different countries. All data point to continuing rapid expansion in the diamond tool sector. The West consumes 80 percent of world industrial diamond production. Diamond consumption increased sharply in the U.S. during World War 2. There are 300 diamond manufacturers in the U.S. today. In 1940, there were 25. In Japan, consumption of industrial diamonds has increased several times. In Italy, there has been a 75 fold increase in the production of diamond tools since 1959.

  8. The low coherence Fabry-Pérot interferometer with diamond and ZnO layers

    Science.gov (United States)

    Majchrowicz, D.; Den, W.; Hirsch, M.

    2016-09-01

    The authors present a fiber-optic Fabry-Pérot interferometer built with the application of diamond and zinc oxide (ZnO) thin layers. Thin ZnO films were deposited on the tip of a standard telecommunication single-mode optical fiber (SMF- 28) while the diamond layer was grown on the plate of silicon substrate. Investigated ZnO layers were fabricated by atomic layer deposition (ALD) and the diamond films were deposited using Microwave Plasma Enhanced Chemical Vapor Deposition (μPE CVD) system. Different thickness of layers was examined. The measurements were performed for the fiber-optic Fabry-Pérot interferometer working in the reflective mode. Spectra were registered for various thicknesses of ZnO layer and various length of the air cavity. As a light source, two superluminescent diodes (SLD) with central wavelength of 1300 nm and 1550 nm were used in measurement set-up.

  9. Proton recoil telescope based on diamond detectors for measurement of fusion neutrons

    CERN Document Server

    Caiffi, B; Ripani, M; Pillon, M; Taiuti, M

    2015-01-01

    Diamonds are very promising candidates for the neutron diagnostics in harsh environments such as fusion reactor. In the first place this is because of their radiation hardness, exceeding that of Silicon by an order of magnitude. Also, in comparison to the standard on-line neutron diagnostics (fission chambers, silicon based detectors, scintillators), diamonds are less sensitive to $\\gamma$ rays, which represent a huge background in fusion devices. Finally, their low leakage current at high temperature suppresses the detector intrinsic noise. In this talk a CVD diamond based detector has been proposed for the measurement of the 14 MeV neutrons from D-T fusion reaction. The detector was arranged in a proton recoil telescope configuration, featuring a plastic converter in front of the sensitive volume in order to induce the (n,p) reaction. The segmentation of the sensitive volume, achieved by using two crystals, allowed to perform measurements in coincidence, which suppressed the neutron elastic scattering backg...

  10. Laser reflection spot as a pattern in a diamond coating – a microscopic study

    Directory of Open Access Journals (Sweden)

    GORDANA S. RISTIĆ

    2009-07-01

    Full Text Available Diamond coatings were deposited by the synchronous and coupled action of a hot filament CVD method and a pulsed CO2 laser in spectro-absorbing and spectro-non-absorbing diamond precursor atmospheres. The obtained coatings were structured/patterned, i.e., they were comprised of uncovered, bare locations. An extra effect observed only in the spectro-active diamond precursor atmosphere was the creation of another laser spot in the coating – a reflection spot. In order to establish the practical usability of the latter one, extensive microscopic investigations were performed with consideration of the morphology changes in the spot of the direct laser beam. Normal incidence SEM images of this spot showed a smooth surface, without any pulse radiation damage. AFM imaging revealed the actual surface condition and gave precise data on the surface characteristics.

  11. Enhancing the plasma illumination behaviour of microplasma devices using microcrystalline/ultra-nanocrystalline hybrid diamond materials as cathodes.

    Science.gov (United States)

    Chang, Tinghsun; Lou, Shiucheng; Chen, Huangchin; Chen, Chulung; Lee, Chiyoung; Tai, Nyanhwa; Lin, Inan

    2013-08-21

    The properties of capacity-type microplasma devices were significantly enhanced due to the utilisation of hybrid diamond films as cathodes. The performance of the microplasma devices was closely correlated with the electron field emission (EFE) properties of the diamond cathode materials. The nanoemitters, which were prepared by growing duplex-structured diamond films [microcrystalline diamond (MCD)/ultra-nanocrystalline diamond (UNCD)] on Si-pyramid templates via a two-step microwave plasma enhanced chemical vapour deposition (MPE-CVD) process, exhibited improved EFE properties (E0 = 5.99 V μm(-1), J(e) = 1.10 mA cm(-2) at 8.50 V μm(-1) applied field), resulting in superior microplasma device performance (with a lower threshold field of 200 V mm(-1) and a higher plasma current density of 7.80 mA cm(-2)) in comparison with UNCD film devices prepared using a single-step MPE-CVD process. The superior EFE properties of the duplex-structured MCD-UNCD films relative to those of the UNCD films can be attributed to the unique granular structure of the diamond films. High-resolution transmission electron microscopy reveals that the MCD-UNCD films consisted of abundant graphitic phases located at the periphery of large diamond aggregates and at the boundaries between the ultra-small diamond grains. The presence of the graphite phase is presumed to be the prime factor that renders these films more conductive and causes these films to exhibit higher EFE properties, thus resulting in the improved plasma illumination properties of the microplasma devices.

  12. Cold Vacuum Drying (CVD) Set Point Determination

    Energy Technology Data Exchange (ETDEWEB)

    PHILIPP, B.L.

    2000-01-12

    This document provides the calculations used to determine the error of safety class signals used for the CVD process These errors are used with the Parameter limits to arrive at the initial set point. The Safety Class Instrumentation and Control (SCIC) system provides active detection and response to process anomalies that, if unmitigated would result in a safety event. Specifically actuation of the SCIC system includes two portions. The portion which isolates the MCO and initiates the safety-class helium (SCHe) purge, and the portion which detects and stops excessive heat input to the MCO on high tempered water MCO inlet temperature. For the MCO isolation and purge the SCIC receives signals from MCO pressure (both positive pressure and vacuum) helium flow rate, bay high temperature switches, seismic trips and time under vacuum trips.

  13. Structure and properties of diamond and diamond-like films

    Energy Technology Data Exchange (ETDEWEB)

    Clausing, R.E. [Oak Ridge National Lab., TN (United States)

    1993-01-01

    This section is broken into four parts: (1) introduction, (2) natural IIa diamond, (3) importance of structure and composition, and (4) control of structure and properties. Conclusions of this discussion are that properties of chemical vapor deposited diamond films can compare favorably with natural diamond, that properties are anisotropic and are a strong function of structure and crystal perfection, that crystal perfection and morphology are functions of growth conditions and can be controlled, and that the manipulation of texture and thereby surface morphology and internal crystal perfection is an important step in optimizing chemically deposited diamond films for applications.

  14. Premature menopause linked to CVD and osteoporosis.

    Science.gov (United States)

    Park, Claire; Overton, Caroline

    2010-03-01

    Premature menopause affects 1% of women under the age of 40, the usual age of the menopause is 51. Most women will present with irregular periods or no periods at all with or without climacteric symptoms. Around 10% of women present with primary amenorrhoea. A careful history and examination are required. It is important to ask specifically about previous chemotherapy or radiotherapy and to look for signs of androgen excess e.g. polycystic ovarian syndrome, adrenal problems e.g. galactorrhoea and thyroid goitres. Once pregnancy has been excluded, a progestagen challenge test can be performed in primary care. Norethisterone 5 mg tds po for ten days or alternatively medroxyprogesterone acetate 10 mg daily for ten days is prescribed. A withdrawal bleed within a few days of stopping the norethisterone indicates the presence of oestrogen and bleeding more than a few drops is considered a positive withdrawal bleed. The absence of a bleed indicates low levels of oestrogen, putting the woman at risk of CVD and osteoporosis. FSH levels above 30 IU/l are an indicator that the ovaries are failing and the menopause is approaching or has occurred. It should be remembered that FSH levels fluctuate during the month and from one month to the next, so a minimum of two measurements should be made at least four to six weeks apart. The presence of a bleed should not exclude premature menopause as part of the differential diagnosis as there can be varying and unpredictable ovarian function remaining. The progestagen challenge test should not be used alone, but in conjunction with FSH, LH and oestradiol. There is no treatment for premature menopause. Women desiring pregnancy should be referred to a fertility clinic and discussion of egg donation. Women not wishing to become pregnant should be prescribed HRT until the age of 50 to control symptoms of oestrogen deficiency and reduce the risks of osteoporosis and CVD.

  15. Plasma Processes : Microwave plasma deposition of diamond like carbon coatings

    Indian Academy of Sciences (India)

    D S Patil; K Ramachandran; N Venkatramani; M Pandey; R D'Cunha

    2000-11-01

    The promising applications of the microwave plasmas have been appearing in the fields of chemical processes and semiconductor manufacturing. Applications include surface deposition of all types including diamond/diamond like carbon (DLC) coatings, etching of semiconductors, promotion of organic reactions, etching of polymers to improve bonding of the other materials etc. With a 2.45 GHz, 700 W, microwave induced plasma chemical vapor deposition (CVD) system set up in our laboratory we have deposited diamond like carbon coatings. The microwave plasma generation was effected using a wave guide single mode applicator. We have deposited DLC coatings on the substrates like stainless steel, Cu–Be, Cu and Si. The deposited coatings have been characterized by FTIR, Raman spectroscopy and ellipsometric techniques. The results show that we have achieved depositing ∼ 95% sp3 bonded carbon in the films. The films are uniform with golden yellow color. The films are found to be excellent insulators. The ellipsometric measurements of optical constant on silicon substrates indicate that the films are transparent above 900 nm.

  16. Microwave plasma deposition of diamond like carbon coatings

    Science.gov (United States)

    Patil, D. S.; Ramachandran, K.; Venkataramani, N.; Pandey, M.; D'Cunha, R.

    2000-11-01

    he promising applications of the microwave plasmas have been appearing in the fields of chemical processes and semiconductor manufacturing. Applications include surface deposition of all types including diamond/diamond like carbon (DLC) coatings, etching of semiconductors, promotion of organic reactions, etching of polymers to improve bonding of the other materials etc. With a 2.45 GHz, 700 W, microwave induced plasma chemical vapor deposition (CVD) system set up in our laboratory we have deposited diamond like carbon coatings. The microwave plasma generation was effected using a wave guide single mode applicator. We have deposited DLC coatings on the substrates like stainless steel, Cu--Be, Cu and Si. The deposited coatings have been characterized by FTIR, Raman spectroscopy and ellipsometric techniques. The results show that we have achieved depositing ~ 95% sp3 bonded carbon in the films. The films are uniform with golden yellow color. The films are found to be excellent insulators. The ellipsometric measurements of optical constant on silicon substrates indicate that the films are transparent above 900 nm.

  17. Electric field deformation in diamond sensors induced by radiation defects

    Energy Technology Data Exchange (ETDEWEB)

    Kassel, Florian; Boer, Wim de; Boegelspacher, Felix; Dierlamm, Alexander; Mueller, Thomas; Steck, Pia [Institut fuer Experimentelle Kernphysik (IEKP), Karlsruher Institut fuer Technologie (KIT) (Germany); Dabrowski, Anne; Guthoff, Moritz [CERN (Switzerland)

    2016-07-01

    The BCML system is a beam monitoring device in the CMS experiment at the LHC. As detectors 32 poly-crystalline CVD diamond sensors are positioned in a ring around the beam pipe at a distance of ±1.8 m and ±14.4 m from the interaction point. The radiation hardness of the diamond sensors in terms of measured signal during operation was significantly lower than expected from laboratory measurements. At high particle rates, such as those occurring during the operation of the LHC, a significant fraction of the defects act as traps for charge carriers. This space charge modifies the electrical field in the sensor bulk leading to a reduction of the charge collection efficiency (CCE). A diamond irradiation campaign was started to investigate the rate dependent electrical field deformation with respect to the radiation damage. Besides the electrical field measurements via the Transient Current Technique, the CCE was measured. The experimental results were used to create an effective trap model that takes the radiation damage into account. Using this trap model the rate dependent electrical field deformation and the CCE were simulated with the software ''SILVACO TCAD''. This talk compares the experimental measurement results with the simulations.

  18. Genetics Home Reference: Diamond-Blackfan anemia

    Science.gov (United States)

    ... Home Health Conditions Diamond-Blackfan anemia Diamond-Blackfan anemia Printable PDF Open All Close All Enable Javascript ... view the expand/collapse boxes. Description Diamond-Blackfan anemia is a disorder of the bone marrow . The ...

  19. Nanocrystalline diamond films for biomedical applications

    DEFF Research Database (Denmark)

    Pennisi, Cristian Pablo; Alcaide, Maria

    2014-01-01

    Nanocrystalline diamond films, which comprise the so called nanocrystalline diamond (NCD) and ultrananocrystalline diamond (UNCD), represent a class of biomaterials possessing outstanding mechanical, tribological, and electrical properties, which include high surface smoothness, high corrosion re...

  20. Biological applications of nanocrystalline diamond

    OpenAIRE

    Williams, Oliver; Daenen, Michael; Haenen, Ken

    2007-01-01

    Nanocrystalline diamond films have generated substantial interest in recent years due to their low cost, extreme properties and wide application arena. Diamond is chemically inert, has a wide electrochemical window and is stable in numerous harsh environments. Nanocrystalline diamond has the advantage of being readily grown on a variety of substrates at very low thickness, resulting in smooth conformal coatings with high transparency. These films can be doped from highly insulating to metalli...

  1. Shengli Diamond Bits

    Institute of Scientific and Technical Information of China (English)

    Yang Yukun; Han Tao

    1995-01-01

    @@ The geologic condition of Shengli Oilfield (SLOF)is complicated and the range of the rock drillability is wide. For more than 20 years,Shengli Drilling Technology Research Institute, in view of the formation conditions of SLOF,has done a lot of effort and obtained many achivements in design,manufacturing technology and field service. Up to now ,the institute has developed several ten kinds of diamond bits applicable for drilling and coring in formations from extremely soft to hard.

  2. Diamond turning of glass

    Energy Technology Data Exchange (ETDEWEB)

    Blackley, W.S.; Scattergood, R.O.

    1988-12-01

    A new research initiative will be undertaken to investigate the critical cutting depth concepts for single point diamond turning of brittle, amorphous materials. Inorganic glasses and a brittle, thermoset polymer (organic glass) are the principal candidate materials. Interrupted cutting tests similar to those done in earlier research are Ge and Si crystals will be made to obtain critical depth values as a function of machining parameters. The results will provide systematic data with which to assess machining performance on glasses and amorphous materials

  3. Rare genetic variants associated with early onset CVD

    NARCIS (Netherlands)

    Maiwald, S.

    2015-01-01

    Cardiovascular disease (CVD) is the major cause of morbidity and mortality in Western societies. CVD is mainly triggered by atherosclerosis. A combination of lipid accumulation, inflammation at the vessel wall and thrombotic reactions are underlying its pathobiology. Despite improvements in the ther

  4. Prevention: Reducing the risk of CVD in patients with periodontitis.

    Science.gov (United States)

    Genco, Robert J; Van Dyke, Thomas E

    2010-09-01

    The association between periodontitis and other chronic diseases, such as cardiovascular disease (CVD) and type 2 diabetes mellitus, could be related to systemic inflammation initiated by a local inflammatory challenge. Oliveira et al. have added lack of oral hygiene, and its link with systemic inflammation, to the spectrum of risk factors for CVD.

  5. Heat transfer model of an iCVD reactor

    NARCIS (Netherlands)

    Bakker, R.; Verlaan, V.; Verkerk, A.D.; van der Werf, C.H.M.; van Dijk, L.; Rudolph, H.; Rath, J.K.; Schropp, R.E.I.

    2009-01-01

    Contrary to conventional HWCVD, the power consumption in the iCVD process is dominated by heat conduction rather than radiation. This is due to the fact that while the typical wire temperature for HWCVD is about 1750–2200 °C, for iCVD the temperature is only 250–500 °C. Typical deposition pressures

  6. ITER ECRH Upper Launcher: Test plan for qualification of the Diamond Torus Window Prototype III

    Energy Technology Data Exchange (ETDEWEB)

    Schreck, Sabine, E-mail: sabine.schreck@kit.edu [Karlsruhe Institute of Technology, Institute for Applied Materials, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Aiello, Gaetano; Meier, Andreas; Strauss, Dirk [Karlsruhe Institute of Technology, Institute for Applied Materials, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Gagliardi, Mario; Saibene, Gabriella [F4E, Antennas and Plasma Engineering, Josep Pla 2, Torres Diagonal Litoral B3, 08019 Barcelona (Spain); Scherer, Theo [Karlsruhe Institute of Technology, Institute for Applied Materials, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2016-11-01

    Highlights: • A qualification program for the ITER diamond torus window is being developed. • The testing program for the qualification of the bare diamond disk is defined. • First qualification tests show a very good quality of the diamond disk prototypes. - Abstract: The diamond window is part of the electron cyclotron heating upper launcher system for ITER. Together with the isolation valve it constitutes the primary vacuum boundary and it also acts as first tritium barrier. Therefore the window is classified as Safety/Protection Important Component (SIC/PIC) with the nuclear safety function “confinement”. As the diamond window unit is not entirely covered by standard codes, an ad-hoc qualification program needs to be defined, including analysis, prototyping and testing. In the framework of a contract with F4E, the test program for a diamond window prototype is being developed with the aim to prove its operability for normal, accidental and incidental conditions as identified in the ITER load specifications. Tests range from dielectric loss measurements for the bare Chemical Vapour Deposition (CVD) diamond disk up to mechanical and vacuum tests for the complete window assembly. Finally mm-wave properties have to be characterized for the complete window. A clear definition of the testing requirements and of the acceptance criteria is necessary as well as a complete documentation of the process. This paper will present the development of the test plan for a window prototype, which is currently under manufacturing. First tests are directed to the characterization of the bare diamond disk with a focus on its dielectric properties.

  7. Low temperature surface conductivity of hydrogenated diamond

    Energy Technology Data Exchange (ETDEWEB)

    Sauerer, C.; Ertl, F.; Nebel, C.E.; Stutzmann, M. [Technische Univ. Muenchen, Garching (Germany). Walter-Schottky-Inst. fuer Physikalische Grundlagen der Halbleiterelektronik; Bergonzo, P. [LIST(CEA-Recherche Technology)/DIMIR/SIAR/Saclay, Gif-sur-Yvette (France); Williams, O.A.; Jackman, R.A. [University Coll., London (United Kingdom). Dept. of Electrical and Electronic Engineering

    2001-07-23

    Conductivity and Hall experiments are performed on hydrogenated poly-CVD, atomically flat homoepitaxially grown Ib and natural type IIa diamond layers in the regime 0.34 to 400 K. For all experiments hole transport is detected with sheet resistivities at room temperature in the range 10{sup 4} to 10{sup 5} {omega}/{radical}. We introduce a transport model where a disorder induced tail of localized states traps holes at very low temperatures (T < 70 K). The characteristic energy of the tail is in the range of 6 meV. Towards higher temperatures (T > 70 K) the hole density is approximately constant and the hole mobility {mu} is increasing two orders of magnitude. In the regime 70 K < T < 200 K, {mu} is exponentially activated with 22 meV, above it follows a {proportional_to}T{sup 3/2} law. The activation energy of the hole density at T < 70 K is governed by the energy gap between holes trapped in the tail and the mobility edge which they can propagate. In the temperature regime T < 25 K an increasing hole mobility is detected which is attributed to transport in delocalized states at the surface. (orig.)

  8. Graphene diamond-like carbon films heterostructure

    Science.gov (United States)

    Zhao, Fang; Afandi, Abdulkareem; Jackman, Richard B.

    2015-03-01

    A limitation to the potential use of graphene as an electronic material is the lack of control over the 2D materials properties once it is deposited on a supporting substrate. Here, the use of Diamond-like Carbon (DLC) interlayers between the substrate and the graphene is shown to offer the prospect of overcoming this problem. The DLC films used here, more properly known as a-C:H with ˜25% hydrogen content, have been terminated with N or F moieties prior to graphene deposition. It is found that nitrogen terminations lead to an optical band gap shrinkage in the DLC, whilst fluorine groups reduce the DLC's surface energy. CVD monolayer graphene subsequently transferred to DLC, N terminated DLC, and F terminated DLC has then been studied with AFM, Raman and XPS analysis, and correlated with Hall effect measurements that give an insight into the heterostructures electrical properties. The results show that different terminations strongly affect the electronic properties of the graphene heterostructures. G-F-DLC samples were p-type and displayed considerably higher mobility than the other heterostructures, whilst G-N-DLC samples supported higher carrier densities, being almost metallic in character. Since it would be possible to locally pattern the distribution of these differing surface terminations, this work offers the prospect for 2D lateral control of the electronic properties of graphene layers for device applications.

  9. Graphene diamond-like carbon films heterostructure

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Fang; Afandi, Abdulkareem; Jackman, Richard B., E-mail: r.jackman@ucl.ac.uk [London Centre for Nanotechnology, Electronic and Electrical Engineering Department, University College London, 17-19 Gordon Street, London WC1H 0AH (United Kingdom)

    2015-03-09

    A limitation to the potential use of graphene as an electronic material is the lack of control over the 2D materials properties once it is deposited on a supporting substrate. Here, the use of Diamond-like Carbon (DLC) interlayers between the substrate and the graphene is shown to offer the prospect of overcoming this problem. The DLC films used here, more properly known as a-C:H with ∼25% hydrogen content, have been terminated with N or F moieties prior to graphene deposition. It is found that nitrogen terminations lead to an optical band gap shrinkage in the DLC, whilst fluorine groups reduce the DLC's surface energy. CVD monolayer graphene subsequently transferred to DLC, N terminated DLC, and F terminated DLC has then been studied with AFM, Raman and XPS analysis, and correlated with Hall effect measurements that give an insight into the heterostructures electrical properties. The results show that different terminations strongly affect the electronic properties of the graphene heterostructures. G-F-DLC samples were p-type and displayed considerably higher mobility than the other heterostructures, whilst G-N-DLC samples supported higher carrier densities, being almost metallic in character. Since it would be possible to locally pattern the distribution of these differing surface terminations, this work offers the prospect for 2D lateral control of the electronic properties of graphene layers for device applications.

  10. First dose-map measured with a polycrystalline diamond 2D dosimeter under an intensity modulated radiotherapy beam

    Energy Technology Data Exchange (ETDEWEB)

    Scaringella, M., E-mail: scaringella@gmail.com [Università di Firenze, Dipartimento di Ingegneria dell’Informazione, Firenze (Italy); Zani, M. [INFN Sezione di Firenze, Sesto Fiorentino, Firenze (Italy); Università di Firenze, Dipartimento di Scienze Biomediche, Sperimentali e Cliniche, Firenze (Italy); Baldi, A. [Università di Firenze, Dipartimento di Ingegneria Industriale, Firenze (Italy); Bucciolini, M. [INFN Sezione di Firenze, Sesto Fiorentino, Firenze (Italy); Università di Firenze, Dipartimento di Scienze Biomediche, Sperimentali e Cliniche, Firenze (Italy); Pace, E.; Sio, A. de [INFN Sezione di Firenze, Sesto Fiorentino, Firenze (Italy); Università di Firenze, Dipartimento di Fisica e Astronomia, Sesto Fiorentino, Firenze (Italy); Talamonti, C. [INFN Sezione di Firenze, Sesto Fiorentino, Firenze (Italy); Università di Firenze, Dipartimento di Scienze Biomediche, Sperimentali e Cliniche, Firenze (Italy); Bruzzi, M. [INFN Sezione di Firenze, Sesto Fiorentino, Firenze (Italy); Università di Firenze, Dipartimento di Fisica e Astronomia, Sesto Fiorentino, Firenze (Italy)

    2015-10-01

    A prototype of bidimensional dosimeter made on a 2.5×2.5 cm{sup 2} active area polycrystalline Chemical Vapour Deposited (pCVD) diamond film, equipped with a matrix of 12×12 contacts connected to the read-out electronics, has been used to evaluate a map of dose under Intensity Modulated Radiation Therapy (IMRT) fields for a possible application in pre-treatment verifications of cancer treatments. Tests have been performed under a 6–10 MVRX beams with IMRT fields for prostate and breast cancer. Measurements have been taken by measuring the 144 pixels in different positions, obtained by shifting the device along the x/y axes to span a total map of 14.4×10 cm{sup 2}. Results show that absorbed doses measured by our pCVD diamond device are consistent with those calculated by the Treatment Planning System (TPS)

  11. CVD carbon powders modified by ball milling

    Directory of Open Access Journals (Sweden)

    Kazmierczak Tomasz

    2015-09-01

    Full Text Available Carbon powders produced using a plasma assisted chemical vapor deposition (CVD methods are an interesting subject of research. One of the most interesting methods of synthesizing these powders is using radio frequency plasma. This method, originally used in deposition of carbon films containing different sp2/sp3 ratios, also makes possible to produce carbon structures in the form of powder. Results of research related to the mechanical modification of these powders have been presented. The powders were modified using a planetary ball mill with varying parameters, such as milling speed, time, ball/powder mass ratio and additional liquids. Changes in morphology and particle sizes were measured using scanning electron microscopy and dynamic light scattering. Phase composition was analyzed using Raman spectroscopy. The influence of individual parameters on the modification outcome was estimated using statistical method. The research proved that the size of obtained powders is mostly influenced by the milling speed and the amount of balls. Powders tend to form conglomerates sized up to hundreds of micrometers. Additionally, it is possible to obtain nanopowders with the size around 100 nm. Furthermore, application of additional liquid, i.e. water in the process reduces the graphitization of the powder, which takes place during dry milling.

  12. Raman modes in transferred bilayer CVD graphene

    Directory of Open Access Journals (Sweden)

    Niilisk Ahti

    2015-01-01

    Full Text Available A systematic experimental Raman spectroscopic study of twisted bilayer graphene (tBLG domains localized inside wide-area single layer graphene (SLG produced by low-pressure CVD on Cu foil and transferred onto SiO2/Si substrate has been performed. According to the Raman characterization the tBLG domains had a great variety of twisting angles θ between the bottom and top graphene layers (6° < θ < 25°. The twisting angle θ was estimated from the spectral position of the rotating R and R' modes in the Raman spectrum.Under G band resonance conditions the breathing mode ZO' with a frequency of 95- 97 cm−1 was detected, and a breathing mode ZO was found in the spectra between 804 cm−1 and 836 cm−1, its position depending on the twisting angle θ. An almost linear relationship was found between the frequencies ωZO and ωR. Also a few other spectral peculiarities were found, e.g. a high-energy excitation of the G band resonance, the 2G overtone appearing at 3170-3180 cm−1 by the G band resonance, revealing a linear dispersion of 80 cm−1/eV of the 2D band in tBLG

  13. A comparative study of the field emission properties of aligned carbon nanostructures films, from carbon nanotubes to diamond

    OpenAIRE

    Le Normand, Francois; Cojocaru, Costel Sorin; Fleaca, Claudiu; Li, J. Q.; Vincent, Pascal; Pirio, Gilles; Gangloff, Laurent; Nedellec, Yanick; Legagneux, Pierre

    2007-01-01

    International audience; The electron field emission properties of different graphitic and diamond-like nanostructures films are compared. They are prepared in the same CVD chamber on SiO{2}/Si(100) and Si(100) flat surfaces, respectively. These nanostructures are thoroughly characterized by scanning electron emission (SEM), transmission electron microscopy (TEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). Films of dense aligned carbon nan...

  14. High efficiency diamond solar cells

    Science.gov (United States)

    Gruen, Dieter M.

    2008-05-06

    A photovoltaic device and method of making same. A layer of p-doped microcrystalline diamond is deposited on a layer of n-doped ultrananocrystalline diamond such as by providing a substrate in a chamber, providing a first atmosphere containing about 1% by volume CH.sub.4 and about 99% by volume H.sub.2 with dopant quantities of a boron compound, subjecting the atmosphere to microwave energy to deposit a p-doped microcrystalline diamond layer on the substrate, providing a second atmosphere of about 1% by volume CH.sub.4 and about 89% by volume Ar and about 10% by volume N.sub.2, subjecting the second atmosphere to microwave energy to deposit a n-doped ultrananocrystalline diamond layer on the p-doped microcrystalline diamond layer. Electrodes and leads are added to conduct electrical energy when the layers are irradiated.

  15. Designing of concrete diamond sawblade

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shao-he; DING Xin-yu; ZHOU Jia-xiang

    2005-01-01

    By analyzing the abrasive theory of concrete diamond sawblade, the proposal that the diamond should be selected by its function in cutting concrete is presented. The part of the big grit diamonds cut rock, and the part of the small grit diamonds improve the wearability of the matrix. The contrast tests are done with different shapes of sawbaldes in split segment, slant "U" slot segment, sandwich segment, turbo segment and three-slot segment. The special shapes of sawblades can improve the effect of cooling and the removing ability of the rock powder. The data of tests show that the efficiency of cutting and the life of sawblades are improved by designing the diamond prescription and using the especial geometry of segment.

  16. Diamond Anvil Cell Techniques

    Science.gov (United States)

    Piermarini, Gasper J.

    It has often been said that scientific advances are made either in a dramatic and revolutionary way, or, as in the case of the diamond anvil cell (DAC), in a slow and evolutionary manner over a period of several years. For more than 2 decades, commencing in 1958, the DAC developed stepwise from a rather crude qualitative instrument to the sophisticated quantitative research tool it is today, capable of routinely producing sustained static pressures in the multi-megabar range and readily adaptable to numerous scientific measurement techniques because of its optical accessibility, miniature size, and portability.

  17. Primitive helium in diamonds

    Science.gov (United States)

    Ozima, M.; Zashu, S.

    1983-03-01

    He-3/He-4 isotopic ratio analyses of 13 diamond stones from unspecified mines in South Africa yield values ranging from less than 10 to the -7th to 0.00032 + or - 0.000025. The latter value is higher than the primordial He-3/He-4 ratio in meteorites, and close to the ratio for solar type He. It is suggested that these elevated values may represent primitive He which has evolved little, in view of its minute increase in radiogenic He-4, since the earth's formation.

  18. Heteroepitaxial Diamond Growth

    Science.gov (United States)

    1993-01-12

    interstitials, respectively. The energies required for the planar to puckered distortion are 4.3 eV on Ni(l 11), 3.0 eV with the Na interstitial, 3.6 eV with H...give consideration to the crystallographic I alignment between diamond tiles to minimize dislocation densities at the " seams ". 3 Methods of checking the...crystallographic alignment (non-destructively) and assessing the dislocation densities at seams must be used to establish the viability of 3 any

  19. Synthesis of Diamond Films with Pulsed Plasma

    Science.gov (United States)

    1992-03-01

    Diamond and Diamond-Like Films, The Electrochemical Society , Los Angeles, California, Volume 89-12, 114, May 1989. M. Aklufi and D. Brock, "Synthesis Of...Diamond Films By Microwave Generated Pulsed Plasmas," Proceedings of The Second International Symposium On Diamond Materials, The Electrochemical Society , Washington, DC, Volume 91-8, ’ 39, May 1991.

  20. Optical cryocooling of diamond

    Science.gov (United States)

    Kern, M.; Jeske, J.; Lau, D. W. M.; Greentree, A. D.; Jelezko, F.; Twamley, J.

    2017-06-01

    The cooling of solids by optical means only using anti-Stokes emission has a long history of research and achievements. Such cooling methods have many advantages ranging from no moving parts or fluids through to operation in vacuum and may have applications to cryosurgery. However, achieving large optical cryocooling powers has been difficult to manage except in certain rare-earth crystals but these are mostly toxic and not biocompatible. Through study of the emission and absorption cross sections we find that diamond, containing either nitrogen vacancy (NV) or silicon vacancy defects, shows potential for optical cryocooling and, in particular, NV doping shows promise for optical refrigeration. We study the optical cooling of doped diamond microcrystals ranging 10-250 μ m in diameter trapped either in vacuum or in water. For the vacuum case we find NV-doped microdiamond optical cooling below room temperature could exceed |Δ T |>10 K for irradiation powers of Pin<100 mW. We predict that such temperature changes should be easily observed via large alterations in the diffusion constant for optically cryocooled microdiamonds trapped in water in an optical tweezer or via spectroscopic signatures such as the zero-phonon line width or Raman line.

  1. Transmission diamond imaging detector

    Energy Technology Data Exchange (ETDEWEB)

    Smedley, John, E-mail: smedley@bnl.gov; Pinelli, Don; Gaoweia, Mengjia [Brookhaven National Laboratory, Upton, NY (United States); Muller, Erik; Ding, Wenxiang; Zhou, Tianyi [Stony Brook University, Stony Brook, NY (United States); Bohon, Jen [Case Center for Synchrotron Biosciences, Center for Proteomics and Bioinformatics, Case Western Reserve University, Cleveland, OH (United States)

    2016-07-27

    Many modern synchrotron techniques are trending toward use of high flux beams and/or beams which require enhanced stability and precise understanding of beam position and intensity from the front end of the beamline all the way to the sample. For high flux beams, major challenges include heat load management in optics (including the vacuum windows) and a mechanism of real-time volumetric measurement of beam properties such as flux, position, and morphology. For beam stability in these environments, feedback from such measurements directly to control systems for optical elements or to sample positioning stages would be invaluable. To address these challenges, we are developing diamond-based instrumented vacuum windows with integrated volumetric x-ray intensity, beam profile and beam-position monitoring capabilities. A 50 µm thick single crystal diamond has been lithographically patterned to produce 60 µm pixels, creating a >1kilopixel free-standing transmission imaging detector. This device, coupled with a custom, FPGA-based readout, has been used to image both white and monochromatic x-ray beams and capture the last x-ray photons at the National Synchrotron Light Source (NSLS). This technology will form the basis for the instrumented end-station window of the x-ray footprinting beamline (XFP) at NSLS-II.

  2. Presolar Diamond in Meteorites

    CERN Document Server

    Amari, Sachiko

    2009-01-01

    Presolar diamond, the carrier of the isotopically anomalous Xe component Xe-HL, was the first mineral type of presolar dust that was isolated from meteorites. The excesses in the light, p-process only isotopes 124Xe and 126Xe, and in the heavy, r-process only isotopes 134Xe and 136Xe relative to the solar ratios indicate that Xe-HL was produced in supernovae: they are the only stellar source where these two processes are believed to take place. Although these processes occur in supernovae, their physical conditions and timeframes are completely different. Yet the excesses are always correlated in diamond separates from meteorites. Furthermore, the p-process 124Xe/126Xe inferred from Xe-L and the r-process 134Xe/136Xe from Xe-H do not agree with the p-process and r-process ratios derived from the solar system abundance, and the inferred p-process ratio does not agree with those predicted from stellar models. The 'rapid separation scenario', where the separation of Xe and its radiogenic precursors Te and I take...

  3. TEPC Microdosimeter for LEO and Beyond Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A new generation of Tissue Equivalent Proportional Counters (TEPCs) for micro-dosimetric measurements will be designed, incorporating recent advances in the...

  4. High-Rate Growth and Nitrogen Distribution in Homoepitaxial Chemical Vapour Deposited Single-crystal Diamond

    Institute of Scientific and Technical Information of China (English)

    LI Hong-Dong; ZOU Guang-Tian; WANG Qi-Liang; CHENG Shao-Heng; LI Bo; L(U) Jian-Nan; L(U) Xian-Yi; JIN Zeng-Sun

    2008-01-01

    High rate (> 50 μm/h) growth of homoepitaxial single-crystal diamond (SCD) is carried out by microwave plasma chemical vapour deposition (MPCVD) with added nitrogen in the reactant gases of methane and hydrogen,using a polycrystalline-CVD-diamond-film-made seed holder. Photoluminescence results indicate that the nitrogen concentration is spatially inhomogeneous in a large scale,either on the top surface or in the bulk of those as-grown SCDs.The presence of N-distribution is attributed to the facts: (I) a difference in N-incorporation efficiency and (ii) N-diffusion,resulting from the local growth temperatures changed during the high-rate deposition process.In addition,the formed nitrogen-vacancy centres play a crucial role in N-diffusion through the growing crystal.Based on the N-distribution observed in the as-grown crystals,we propose a simple method to distinguish natural diamonds and man-made CVD SCDs.Finally,the disappearance of void defect on the top surface of SCDs is discussed to be related to a filling-in mechanism.

  5. Radiation damage in the diamond based beam condition monitors of the CMS experiment at the Large Hadron Collider (LHC) at CERN

    Science.gov (United States)

    Guthoff, Moritz; Afanaciev, Konstantin; Dabrowski, Anne; de Boer, Wim; Lange, Wolfgang; Lohmann, Wolfgang; Stickland, David

    2013-12-01

    The Beam Condition Monitor (BCM) of the CMS detector at the LHC is a protection device similar to the LHC Beam Loss Monitor system. While the electronics used is the same, poly-crystalline Chemical Vapor Deposition (pCVD) diamonds are used instead of ionization chambers as the BCM sensor material. The main purpose of the system is the protection of the silicon Pixel and Strip tracking detectors by inducing a beam dump, if the beam losses are too high in the CMS detector. By comparing the detector current with the instantaneous luminosity, the BCM detector efficiency can be monitored. The number of radiation-induced defects in the diamond, reduces the charge collection distance, and hence lowers the signal. The number of these induced defects can be simulated using the FLUKA Monte Carlo simulation. The cross-section for creating defects increases with decreasing energies of the impinging particles. This explains, why diamond sensors mounted close to heavy calorimeters experience more radiation damage, because of the high number of low energy neutrons in these regions. The signal decrease was stronger than expected from the number of simulated defects. Here polarization from trapped charge carriers in the defects is a likely candidate for explaining the difference, as suggested by Transient Current Technique (TCT) measurements. A single-crystalline (sCVD) diamond sensor shows a faster relative signal decrease than a pCVD sensor mounted at the same location. This is expected, since the relative increase in the number of defects is larger in sCVD than in pCVD sensors.

  6. Tailoring nanocrystalline diamond film properties

    Science.gov (United States)

    Gruen, Dieter M.; McCauley, Thomas G.; Zhou, Dan; Krauss, Alan R.

    2003-07-15

    A method for controlling the crystallite size and growth rate of plasma-deposited diamond films. A plasma is established at a pressure in excess of about 55 Torr with controlled concentrations of hydrogen up to about 98% by volume, of unsubstituted hydrocarbons up to about 3% by volume and an inert gas of one or more of the noble gases and nitrogen up to about 98% by volume. The volume ratio of inert gas to hydrogen is preferably maintained at greater than about 4, to deposit a diamond film on a suitable substrate. The diamond film is deposited with a predetermined crystallite size and at a predetermined growth rate.

  7. Micro-texturing into DLC/diamond coated molds and dies via high density oxygen plasma etching

    Directory of Open Access Journals (Sweden)

    Yunata Ersyzario Edo

    2015-01-01

    Full Text Available Diamond-Like Carbon (DLC and Chemical Vapor Deposition (CVD-diamond films have been widely utilized not only as a hard protective coating for molds and dies but also as a functional substrate for bio-MEMS/NEMS. Micro-texturing into these hard coated molds and dies provides a productive tool to duplicate the original mother micro-patterns onto various work materials and to construct any tailored micro-textures for sensors and actuators. In the present paper, the high density oxygen plasma etching method is utilized to make micro-line and micro-groove patterns onto the DLC and diamond coatings. Our developing oxygen plasma etching system is introduced together with characterization on the plasma state during etching. In this quantitative plasma diagnosis, both the population of activated species and the electron and ion densities are identified through the emissive light spectroscopy and the Langmuir probe method. In addition, the on-line monitoring of the plasmas helps to describe the etching process. DLC coated WC (Co specimen is first employed to describe the etching mechanism by the present method. Chemical Vapor Deposition (CVD diamond coated WC (Co is also employed to demonstrate the reliable capacity of the present high density oxygen plasma etching. This oxygen plasma etching performance is discussed by comparison of the etching rates.

  8. Electrostatic Self-Assembly of Diamond Nanoparticles onto Al- and N-Polar Sputtered Aluminum Nitride Surfaces

    Directory of Open Access Journals (Sweden)

    Taro Yoshikawa

    2016-11-01

    Full Text Available Electrostatic self-assembly of diamond nanoparticles (DNPs onto substrate surfaces (so-called nanodiamond seeding is a notable technique, enabling chemical vapor deposition (CVD of nanocrystalline diamond thin films on non-diamond substrates. In this study, we examine this technique onto differently polarized (either Al- or N-polar c-axis oriented sputtered aluminum nitride (AlN film surfaces. This investigation shows that Al-polar films, as compared to N-polar ones, obtain DNPs with higher density and more homogeneously on their surfaces. The origin of these differences in density and homogeneity is discussed based on the hydrolysis behavior of AlN surfaces in aqueous suspensions.

  9. The Diamond Standard Vodka酒

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    对于酒的品味不仅仅在酒本身所散发出的醉人魅力,自古以来,拥有艺术品般精湛做工、华美造犁的盛酒器皿也和酒一样流传千古。The Diamond Standard Vodka以“奢侈”、“豪华”作为卖点,除了散发着北欧风格的高贵气质外,由原产自奥地利的施华洛廿奇水晶制成25mm的瓶身更让它身价倍增。以钻石命名的它使用了钻石过滤专利系统,

  10. Helium and carbon isotopes in Indian diamonds

    Science.gov (United States)

    Wiens, R.; Lal, D.; Craig, H.

    1990-09-01

    Helium and carbon isotope measurements in Indian diamonds (from Andhra Pradesh) were carried out using samples that included mined diamonds from primary kimberlite source rocks and alluvial diamonds from river gravel. The He and C isotope concentrations in diamonds from these two sources were compared, and the Indian diamonds were compared to those from other regions. Results indicate that most of the He-3 in the alluvial diamonds is of cosmogenic origin and that the alluvial diamonds may also have a significant He-4 component due to alpha particles implanted during storage in a secondary matrix. One diamond, a mined kimberlite specimen, was found to have the lowest He-4 content (0.018 microcc/g) so far recorded in diamonds.

  11. Quantum photonic networks in diamond

    KAUST Repository

    Lončar, Marko

    2013-02-01

    Advances in nanotechnology have enabled the opportunity to fabricate nanoscale optical devices and chip-scale systems in diamond that can generate, manipulate, and store optical signals at the single-photon level. In particular, nanophotonics has emerged as a powerful interface between optical elements such as optical fibers and lenses, and solid-state quantum objects such as luminescent color centers in diamond that can be used effectively to manipulate quantum information. While quantum science and technology has been the main driving force behind recent interest in diamond nanophotonics, such a platform would have many applications that go well beyond the quantum realm. For example, diamond\\'s transparency over a wide wavelength range, large third-order nonlinearity, and excellent thermal properties are of great interest for the implementation of frequency combs and integrated Raman lasers. Diamond is also an inert material that makes it well suited for biological applications and for devices that must operate in harsh environments. Copyright © Materials Research Society 2013.

  12. Diamond Detectors for the TOTEM Timing Upgrade arXiv

    CERN Document Server

    Antchev, G.; Atanassov, I.; Avati, V.; Baechler, J.; Berardi, V.; Berretti, M.; Bossini, E.; Bottigli, U.; Bozzo, M.; Broulím, P.; Buzzo, A.; Cafagna, F.S.; Catanesi, M.G.; Csanád, M.; Csörgő, T.; Deile, M.; De Leonardis, F.; D'Orazio, A.; Doubek, M.; Eggert, K.; Eremin, V.; Ferro, F.; Fiergolski, A.; Garcia, F.; Georgiev, V.; Giani, S.; Grzanka, L.; Guaragnella, C.; Hammerbauer, J.; Heino, J.; Karev, A.; Kašpar, J.; Kopal, J.; Kundrát, V.; Lami, S.; Latino, G.; Lauhakangas, R.; Linhart, R.; Lokajíček, M.V.; Losurdo, L.; Lo Vetere, M.; Rodríguez, F. Lucas; Lucsányi, D.; Macrí, M.; Mercadante, A.; Minafra, N.; Minutoli, S.; Naaranoja, T.; Nemes, F.; Niewiadomski, H.; Novák, T.; Oliveri, E.; Oljemark, F.; Oriunno, M.; Österberg, K.; Palazzi, P.; Paločko, L.; Passaro, V.; Peroutka, Z.; Petruzzelli, V.; Politi, T.; Procházka, J.; Prudenzano, F.; Quinto, M.; Radermacher, E.; Radicioni, E.; Ravotti, F.; Robutti, E.; Royon, C.; Ruggiero, G.; Saarikko, H.; Scribano, A.; Smajek, J.; Snoeys, W.; Sziklai, J.; Taylor, C.; Turini, N.; Vacek, V.; Welti, J.; Wyszkowski, P.; Zielinski, K.

    This paper describes the design and the performance of the timing detector developed by the TOTEM Collaboration for the Roman Pots (RPs) to measure the Time-Of-Flight (TOF) of the protons produced in central diffractive interactions at the LHC. The measurement of the TOF of the protons allows the determination of the longitudinal position of the proton interaction vertex and its association with one of the vertices reconstructed by the CMS detectors. The TOF detector is based on single crystal Chemical Vapor Deposition (scCVD) diamond plates and is designed to measure the protons TOF with about 50 ps time precision. This upgrade to the TOTEM apparatus will be used in the LHC run 2 and will tag the central diffractive events up to an interaction pileup of about 1. A dedicated fast and low noise electronics for the signal amplification has been developed. The digitization of the diamond signal is performed by sampling the waveform. After introducing the physics studies that will most profit from the addition of...

  13. Early stages of diamond BEN-HFCVD on iridium

    Energy Technology Data Exchange (ETDEWEB)

    Arnault, J.C.; Faerber, J. [Groupe Surfaces-Interfaces, Institut de Physique et Chimie de Strasbourg, IPCMS-GSI, UMR 7504, BP 43, 23, rue du Loess, 67034 Strasbourg Cedex 2 (France); Vonau, F. [Laboratoire de Physique et Spectroscopie Electronique, 4, rue des Freres Lumiere, 68093 Mulhouse Cedex (France); Arabski, J.; Schmerber, G. [Groupe des Materiaux Metalliques, IPCMS-GEMM, 91404 Orsay (France); Wyczisk, F.; Legagneux, P. [Thales R and T, Domaine de Corbeville, 91404 Orsay Cedex (France)

    2003-09-01

    This study attempts to better understand the BEN effects on diamond nucleation on iridium buffer layers investigated by in situ electron spectroscopies (XPS, AES). The surface morphology is further characterised by AFM and SEM FEG. Nano-Auger experiments provide information about the chemical nature of the crystals. During the early stages of BEN, nano-Auger observations revealed a significant carbon sp{sup 3} contribution within the bright crystals whereas the surrounding areas are mainly sp{sup 2}. This emphasizes the BEN effect on the diamond nucleation. Moreover, AES experiments reveal the formation of graphite. The equivalent thickness of the graphite layer is estimated from XPS data, it is close to a monolayer. The graphite formation is not a proper effect of BEN because it is also obtained under CVD environment according to our study. Anisotrope crystals arranged along left angle 110 right angle directions have been characterized by HR-SEM and AFM. (copyright 2003 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Test of the LHC DIAMOND Beam Loss Monitors

    CERN Document Server

    Dehning, B; Effinger, E; Pernegger, H; Griesmayer, E

    2011-01-01

    Chemical Vapour Deposition(CVD) diamond detectors were installed in the collimation area of the CERN LHC to study their feasibility as Fast Beam Loss Monitors in a high-­radiation environment. Four detectors were configured with fast, radiation-­hard pre-amplifiers with a bandwidth of 2GHz. The readout was via an oscilloscope with a bandwidth of 1GHz and a sampling rate of 5 GSPS. Despite the 250m cable run from the detectors to the oscilloscope, particle losses were resolved with a 2ns rise time, a pulse width of 10ns and a time resolution of 615ps. Two modes of operation were applied. For the analysis of unexpected beam aborts, the loss profile was recorded in a 1ms buffer and, for nominal operation, the histogram of the time structure of the losses was recorded in synchronism with the LHC period of 89.2us. Measurements during the LHC start-­up (February to December 2010) are presented. The Diamond Monitors gave an unprecedented insight into the time structure of the beam losses resolving the LHC RF freq...

  15. Domestic and Industrial Water Disinfection Using Boron-Doped Diamond Electrodes

    Science.gov (United States)

    Rychen, Philippe; Provent, Christophe; Pupunat, Laurent; Hermant, Nicolas

    This chapter first describes main properties and manufacturing process (production using HF-CVD, quality-control measurements, etc.) of diamond electrodes and more specifically boron-doped diamond (BDD) electrodes. Their exceptional properties make such electrodes particularly suited for many disinfection applications as thanks to their wide working potential window and their high anodic potential, they allow generating a mixture of powerful oxidizing species mainly based on active oxygen and peroxides. Such mixture of disinfecting agents is far more efficient than conventional chemical or physical known techniques. Their efficiency was tested against numerous microorganisms and then proved to be greater than conventional methods. All bacteria and viruses tested up to date were inactivated 3-5 times faster with a treatment based on with BDD electrodes and the DiaCellⓇ technology than with other techniques. Several applications, either industrial or private (wellness and home use), are discussed with a focus on the dedicated products and the main technology advantages.

  16. Performance and perspectives of the diamond based Beam Condition Monitor for beam loss monitoring at CMS

    CERN Document Server

    AUTHOR|(CDS)2080862

    2015-01-01

    At CMS, a beam loss monitoring system is operated to protect the silicon detectors from high particle rates, arising from intense beam loss events. As detectors, poly-crystalline CVD diamond sensors are placed around the beam pipe at several locations inside CMS. In case of extremely high detector currents, the LHC beams are automatically extracted from the LHC rings.Diamond is the detector material of choice due to its radiation hardness. Predictions of the detector lifetime were made based on FLUKA monte-carlo simulations and irradiation test results from the RD42 collaboration, which attested no significant radiation damage over several years.During the LHC operational Run1 (2010 â?? 2013), the detector efficiencies were monitored. A signal decrease of about 50 times stronger than expectations was observed in the in-situ radiation environment. Electric field deformations due to charge carriers, trapped in radiation induced lattice defects, are responsible for this signal decrease. This so-called polarizat...

  17. The world's first high voltage GaN-on-Diamond power semiconductor devices

    Science.gov (United States)

    Baltynov, Turar; Unni, Vineet; Narayanan, E. M. Sankara

    2016-11-01

    This paper presents the detailed fabrication method and extensive electrical characterisation results of the first-ever demonstrated high voltage GaN power semiconductor devices on CVD Diamond substrate. Fabricated circular GaN-on-Diamond HEMTs with gate-to-drain drift length of 17 μm and source field plate length of 3 μm show an off-state breakdown voltage of ∼1100 V. Temperature characterisation of capacitance-voltage characteristics and on-state characteristics provides insight on the temperature dependence of key parameters such as threshold voltage, 2DEG sheet carrier concentration, specific on-state resistance, and drain saturation current in the fabricated devices.

  18. Morphology of diamond plate grown in the C-H-O system

    Energy Technology Data Exchange (ETDEWEB)

    Nakanose, M. [Nissan Motor Co. Ltd., Tokyo (Japan); Ichinose, H. [Univ. of Tokyo (Japan)

    1995-12-31

    A ECR-CVD system was newly designed and applied on the growth of large scale plate-like single crystal diamond. The diamond plate was grown on the (200) surface of a heated silicon substrate in H{sub 2}-CO-O{sub 2} mixing gas. Silicon wafers with (110) and (111) surface were also employed as a substrate. A plate like single crystal ten micro meter in size was grown on the (200) surface at 1123K. Top surface of the platelet crystal was very flat and was parallel to (111) plane, which was parallel to the (200) surface of the silicon substrate. Half peak width of the Raman scattering spectra was 2.6 cm{sup {minus}1} showing low impunity content in the platelet crystal less than 1ppm for N and B.

  19. Hydrogenated Black Diamond: An Electrical Study

    Energy Technology Data Exchange (ETDEWEB)

    Williams, O.A.; Jackman, R.B. [Electronic and Electrical Engineering, University College London, Torrington Place, London, WC1E 7JE (United Kingdom); Nebel, C.E. [Walter Schottky Institut, Technische Universitaet Muenchen, Am Coulombwall, 85748 Garching (Germany)

    2002-10-16

    Hydrogen surface conductivity has been a controversial subject since its discovery. Initial plasma treatments on single crystal diamond and polycrystalline diamond have lead to the widespread use of this material in active electronics. However, ''Black'' polycrystalline diamond, usually termed ''Thermal Management Grade'', shows carrier concentration and mobility values similar to both white polycrystalline diamond and single crystal material. Schottky contacts have also been fabricated and show promising characteristics. Black diamond can be grown considerably faster than white diamond and is hence much cheaper. (Abstract Copyright [2002], Wiley Periodicals, Inc.)

  20. Synthesis of CVD-graphene on rapidly heated copper foils.

    Science.gov (United States)

    Kim, Sang-Min; Kim, Jae-Hyun; Kim, Kwang-Seop; Hwangbo, Yun; Yoon, Jong-Hyuk; Lee, Eun-Kyu; Ryu, Jaechul; Lee, Hak-Joo; Cho, Seungmin; Lee, Seung-Mo

    2014-05-07

    Most chemical vapor deposition (CVD) systems used for graphene growth mainly employ convection and radiation heat transfer between the heating source and the metal catalyst in order to reach the activation temperature of the reaction, which in general leads to a long synthesis time and poor energy efficiency. Here, we report a highly time- and energy-efficient CVD setup, in which the metal catalyst (Cu) is designed to be physically contacted with a heating source to give quick heat transfer by conduction. The induced conduction heating enabled the usual effects of the pretreatment and annealing of Cu (i.e., annihilation of surface defects, impurities and contaminants) to be achieved in a significantly shorter time compared to conventional CVD. Notably, the rapid heating was observed to lead to larger grains of Cu with high uniformity as compared to the Cu annealed by conventional CVD, which are believed to be beneficial for the growth of high quality graphene. Through this CVD setup, bundles of high quality (∼252 Ω per square) and large area (over 16 inch) graphenes were able to be readily synthesized in 40 min in a significantly efficient way. When considering ease of scalability, high energy effectiveness and considerable productivity, our method is expected to be welcomed by industrialists.

  1. Diamonds: Exploration, mines and marketing

    Science.gov (United States)

    Read, George H.; Janse, A. J. A. (Bram)

    2009-11-01

    The beauty, value and mystique of exceptional quality diamonds such as the 603 carat Lesotho Promise, recovered from the Letseng Mine in 2006, help to drive a multi-billion dollar diamond exploration, mining and marketing industry that operates in some 45 countries across the globe. Five countries, Botswana, Russia, Canada, South Africa and Angola account for 83% by value and 65% by weight of annual diamond production, which is mainly produced by four major companies, De Beers, Alrosa, Rio Tinto and BHP Billiton (BHPB), which together account for 78% by value and 72% by weight of annual diamond production for 2007. During the last twelve years 16 new diamond mines commenced production and 4 re-opened. In addition, 11 projects are in advanced evaluation and may begin operations within the next five years. Exploration for diamondiferous kimberlites was still energetic up to the last quarter of 2008 with most work carried out in Canada, Angola, Democratic Republic of the Congo (DRC) and Botswana. Many kimberlites were discovered but no new economic deposits were outlined as a result of this work, except for the discovery and possible development of the Bunder project by Rio Tinto in India. Exploration methods have benefitted greatly from improved techniques of high resolution geophysical aerial surveying, new research into the geochemistry of indicator minerals and further insights into the formation of diamonds and the relation to tectonic/structural events in the crust and mantle. Recent trends in diamond marketing indicate that prices for rough diamonds and polished goods were still rising up to the last quarter of 2008 and subsequently abruptly sank in line with the worldwide financial crisis. Most analysts predict that prices will rise again in the long term as the gap between supply and demand will widen because no new economic diamond discoveries have been made recently. The disparity between high rough and polished prices and low share prices of publicly

  2. Genetic Types of Diamond Mineralization

    Institute of Scientific and Technical Information of China (English)

    A.A.MARAKUSHEV; 桑隆康; 等

    1998-01-01

    The paper describes the proposed models of diamond formation both in meteorites and in kimberlite and lamproite bodies.metamorphic complexes and explosive-ring structures ("astroblemes"),The diamond distribution in meteorites(chondrites,iron meteorites and ureilites)is restricted to taente-kamasite phase.The diamond generation here is tied up with the first stage of evolution of the planets,This stage is characterized by high pressure of hydrogen. leading to the formation of the planet envelope,The second stage of planet evolution began with the progressive imopoverishment of their atmospheres in hydrogen due to its predominant emission into the space and to progressive development of oxidative conditions.The model appears to have proved the relict nature of diamond mineraolization in meteorites.Diamond and other high-pressure minerals(its"satellites") were crystallized without any exception in the early intratelluric stages of peridotite and eclogite-pyroxenite magma evolution just before the magma intrusion into the higher levels of the mantle and crust where diamond is not thermodynamically stable,The ultramafic intrusive bodies(bearing rich relict diamonds)in the dase of a platform paaear to be the substrata for the formation of kimberlite-lamproite magma chambers as a result of magmatic replacement.The model explains the polyfacial nature of diamondiferous eclotgites,pyroxenites and peridotites and discusses the process of inheritance of their diamond mineralization by kimberlites and lamproites.Dimond oproductivity of metamorthic complexes is originated by the inheritance of their diamonds from the above-mentioned primary diamondiferous rocks.Large diamondiferous explosive-ring structures were formed by high-energy endogenic explosion of fluid which came from the Earth's core.This high energy differs endogenic impactogenesis from explosive volcanism.It proceeds at very high temperature to create diaplectic galsses(monomineral pseudomorphs)-the product of

  3. Diamond detectors with laser induced surface graphite electrodes

    Science.gov (United States)

    Komlenok, M.; Bolshakov, A.; Ralchenko, V.; Konov, V.; Conte, G.; Girolami, M.; Oliva, P.; Salvatori, S.

    2016-11-01

    We report on the response of metal-less CVD polycrystalline-diamond pixel sensors under β-particles irradiation. A 21×21 array of 0.18×0.18 mm2 pixels was realized on one side of a 10.0×10.0×0.5 mm3 polycrystalline diamond substrate by means of laser induced surface graphitization. With the same technique, a large graphite contact, used for detector biasing, was fabricated on the opposite side. A coincidence detecting method was used with two other reference polycrystalline diamond detectors for triggering, instead of commonly used scintillators, positioned in the front and on the back of the sensor-array with respect to the impinging particles trajectory. The collected charge distribution at each pixel was analyzed as a function of the applied bias. No change in the pulse height distribution was recorded by inverting the bias voltage polarity, denoting contacts ohmicity and symmetry. A fairly good pixel response uniformity was obtained: the collected charge most probable value saturates for all the pixels at an electric field strength of about ±0.6 V/μm. Under saturation condition, the average collected charge was equal to =1.64±0.02 fC, implying a charge collection distance of about 285 μm. A similar result, within 2%, was also obtained for 400 MeV electrons at beam test facility at INFN Frascati National Laboratory. Experimental results highlighted that more than 84% of impinging particles involved only one pixel, with no significant observed cross-talk effects.

  4. Diamond based detectors for high temperature, high radiation environments

    Science.gov (United States)

    Metcalfe, A.; Fern, G. R.; Hobson, P. R.; Smith, D. R.; Lefeuvre, G.; Saenger, R.

    2017-01-01

    Single crystal CVD diamond has many desirable properties as a radiation detector; exceptional radiation hardness and physical hardness, chemical inertness, low Z (close to human tissue, good for dosimetry and transmission mode applications), wide bandgap (high temperature operation with low noise and solar blind), an intrinsic pathway to fast neutron detection through the 12C(n,α)9Be reaction. This combination of radiation hardness, temperature tolerance and ability to detect mixed radiation types with a single sensor makes diamond particularly attractive as a detector material for harsh environments such as nuclear power station monitoring (fission and fusion) and oil well logging. Effective exploitation of these properties requires the development of a metallisation scheme to give contacts that remain stable over extended periods at elevated temperatures (up to 250°C in this instance). Due to the cost of the primary detector material, computational modelling is essential to best utilise the available processing methods for optimising sensor response through geometry and conversion media configurations and to fully interpret experimental data. Monte Carlo simulations of our diamond based sensor have been developed, using MCNP6 and FLUKA2011, assessing the sensor performance in terms of spectral response and overall efficiency as a function of the detector and converter geometry. Sensors with varying metallisation schemes for high temperature operation have been fabricated at Brunel University London and by Micron Semiconductor Limited. These sensors have been tested under a varied set of conditions including irradiation with fast neutrons and alpha particles at high temperatures. The presented study indicates that viable metallisation schemes for high temperature contacts have been successfully developed and the modelling results, supported by preliminary experimental data from partners, indicate that the simulations provide a reasonable representation of

  5. Influence of bowl shaped substrate holder on growth of polymeric DLC film in a microwave plasma CVD reactor

    Indian Academy of Sciences (India)

    Sambita Sahoo; S K Pradhan; Venkateswarlu Bhavanasi; Swati S Pradhan; S N Sarangi; P K Barhai

    2012-12-01

    The properties of diamond like carbon (DLC) films grown in modified microwave plasma CVD reactor is presented in this paper. By using bowl shaped steel substrate holder in a MW plasma CVD reactor (without ECR), films have been grown at relatively high pressure (20Torr) and at low temperature (without heating). The input microwave power was about 300W. Earlier, under the same growth conditions, no deposition was achieved when flat molybdenum/steel substrate holders were used. In this study, two different designs of bowl shaped steel substrate holder at different bias have been experimented. Raman spectra confirm the DLC characteristics of the films. FTIR results indicate that the carbon is bonded in the 3 form with hydrogen, and this characteristic is more pronounced when smaller holder is used. UV-visible spectra show high visible transmittance (∼85%) for films grown in both the holders. The nanoindentation hardness of the films have a wide range, about 4–16GPa. Field emission scanning electron microscope (FESEM) images reveal that the films have featureless and smooth surface morphology. These films are polymeric in nature with moderately high hardness, which may be useful as anti-scratch and anti-corrosive coatings.

  6. Laser diagnostics and modeling of plasma assisted CVD. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-02-01

    Plasma assisted chemical vapor deposition (PACVD) represents a novel approach for utilizing the nonequilibrium effects of reactive plasmas for depositing a wide range of protective hardface coatings that have both wear and erosion application. The nonequilibrium plasma is the heart of this complex system and has the function of generating the reactive molecular fragments (radicals) and atomic species at concentration levels unattainable by other competing processes. It is now widely accepted that such advanced protective hardface coatings materials will play a vital role in the energy technologies of the coming decades, with major applications in diverse areas ranging from aerospace and commercial propulsion systems (jet engines) to automotive components and internal combustion engines, (ceramic heat engines), cutting and machining tools, electronic packaging, thermal management, and possibly room-temperature superconductors. Wear and associated erosion aspects are responsible for an enormous expenditure of energy and fiscal resources in almost all DOE applications. Many of the results from this investigation arc also applicable to other materials processing reactors such as electron beam, PVD, CVD, laser ablation, microwave, high energy cathodic arc, thermal plasma (rf or dc) and combustion spray. These also include the various hybrid systems such as the rf/dc arc as used in Japan for diamond deposition and e-beam PVD deposition of advanced titanium alloy coatings as used at the Paton Institute in Kiev, Ukraine.

  7. Effect of hydrogenation, low energy ion irradiation and annealing on hydrogen bonding to polycrystalline diamond surface studied by high resolution electron energy loss spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Michaelson, S.; Ternyak, O.; Akhvlediani, R.; Hoffman, A. [Schulich Faculty of Chemistry, Technion, Israeli Institute of Technology, Haifa (Israel); Lafosse, A.; Bertin, M.; Azria, R. [Paris-Sud Univ. et CNRS, Lab. des Collisions Atomiques et Moleculaires, 91 - Orsay (France)

    2007-09-15

    The effects of different processes of hydrogenation, thermal treatment and ion irradiation of hydrogenated polycrystalline diamond surface have been investigated by means of high resolution electron energy loss spectroscopy (HR-EELS). Analysis of the different contributions in the CH stretching, overtones and combination modes, as well as changes in relative intensities of the diamond CC and CH{sub x} related vibrations allowed us to identify the CH{sub x} adsorbed species on the diamond surface following the different treatments. Ex-situ hydrogenation of diamond surface by means of exposure to H-MW plasma results in a fully hydrogenated well-ordered diamond surface and etching of the amorphous phase located on the grain boundaries present on the sample after CVD-deposition. Annealing this surface to 600 C results in some subtle changes in the HR-EELS, probably associated with decomposition of CH{sub x} (x=2,3) adsorbed species. Ion irradiation on the surface induces partial desorption of hydrogen from the diamond phase and a large amount of amorphous defects, some of them of sp and the most of them of sp{sup 2} character. Annealing to 600-700 C of the irradiated surface leads to hydrogen desorption. In-situ hydrogenation of the irradiated and annealed sample does not restore the diamond structure, and results in hydrogenated amorphous surface, unstable with thermal annealing above 600-700 C. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. Dedicated multichannel readout ASIC coupled with single crystal diamond for dosimeter application

    Science.gov (United States)

    Fabbri, A.; Falco, M. D.; De Notaristefani, F.; Galasso, M.; Marinelli, M.; Orsolini Cencelli, V.; Tortora, L.; Verona, C.; Verona Rinati, G.

    2013-02-01

    This paper reports on the tests of a low-noise, multi-channel readout integrated circuit used as a readout electronic front-end for a diamond multi-pixel dosimeter. The system is developed for dose distribution measurement in radiotherapy applications. The first 10-channel prototype chip was designed and fabricated in a 0.18 um CMOS process. Every channel includes a charge integrator with a 10 pF capacitor and a double slope A/D converter. The diamond multi-pixel detector, based on CVD synthetic single crystal diamond Schottky diodes, is made by a 3 × 3 sensor matrix. The overall device has been tested under irradiation with 6 MeV radio therapeutic photon beams at the Policlinico ``Tor Vergata'' (PTV) hospital. Measurements show a 20 fA RMS leakage current from the front-end input stage and a negligible dark current from the diamond detector, a stable temporal response and a good linear behaviour as a function of both dose and dose rate. These characteristics were common to each tested channel.

  9. Are diamond nanoparticles cytotoxic?

    Science.gov (United States)

    Schrand, Amanda M; Huang, Houjin; Carlson, Cataleya; Schlager, John J; Omacr Sawa, Eiji; Hussain, Saber M; Dai, Liming

    2007-01-11

    Finely divided carbon particles, including charcoal, lampblack, and diamond particles, have been used for ornamental and official tattoos since ancient times. With the recent development in nanoscience and nanotechnology, carbon-based nanomaterials (e.g., fullerenes, nanotubes, nanodiamonds) attract a great deal of interest. Owing to their low chemical reactivity and unique physical properties, nanodiamonds could be useful in a variety of biological applications such as carriers for drugs, genes, or proteins; novel imaging techniques; coatings for implantable materials; and biosensors and biomedical nanorobots. Therefore, it is essential to ascertain the possible hazards of nanodiamonds to humans and other biological systems. We have, for the first time, assessed the cytotoxicity of nanodiamonds ranging in size from 2 to 10 nm. Assays of cell viability such as mitochondrial function (MTT) and luminescent ATP production showed that nanodiamonds were not toxic to a variety of cell types. Furthermore, nanodiamonds did not produce significant reactive oxygen species. Cells can grow on nanodiamond-coated substrates without morphological changes compared to controls. These results suggest that nanodiamonds could be ideal for many biological applications in a diverse range of cell types.

  10. Integrated diamond networks for quantum nanophotonics

    CERN Document Server

    Hausmann, Birgit J M; Quan, Qimin; Maletinsky, Patrick; McCutcheon, Murray; Choy, Jennifer T; Babinec, Tom M; Kubanek, Alexander; Yacoby, Amir; Lukin, Mikhail D; Loncar, Marko

    2011-01-01

    Diamond is a unique material with exceptional physical and chemical properties that offers potential for the realization of high-performance devices with novel functionalities. For example diamond's high refractive index, transparency over wide wavelength range, and large Raman gain are of interest for the implementation of novel photonic devices. Recently, atom-like impurities in diamond emerged as an exceptional system for quantum information processing, quantum sensing and quantum networks. For these and other applications, it is essential to develop an integrated nanophotonic platform based on diamond. Here, we report on the realization of such an integrated diamond photonic platform, diamond on insulator (DOI), consisting of a thin single crystal diamond film on top of an insulating silicon dioxide/silicon substrate. Using this approach, we demonstrate diamond ring resonators that operate in a wide wavelength range, including the visible (630nm) and near-infrared (1,550nm). Finally, we demonstrate an int...

  11. The Design of Diamond Compton Telescope

    CERN Document Server

    Hibino, Kinya; Okuno, Shoji; Yajima, Kaori; Uchihori, Yukio; Kitamura, Hisashi; Takashima, Takeshi; Yokota, Mamoru; Yoshida, Kenji

    2007-01-01

    We have developed radiation detectors using the new synthetic diamonds. The diamond detector has an advantage for observations of "low/medium" energy gamma rays as a Compton telescope. The primary advantage of the diamond detector can reduce the photoelectric effect in the low energy range, which is background noise for tracking of the Compton recoil electron. A concept of the Diamond Compton Telescope (DCT) consists of position sensitive layers of diamond-striped detector and calorimeter layer of CdTe detector. The key part of the DCT is diamond-striped detectors with a higher positional resolution and a wider energy range from 10 keV to 10 MeV. However, the diamond-striped detector is under development. We describe the performance of prototype diamond detector and the design of a possible DCT evaluated by Monte Carlo simulations.

  12. Anodic bonding of diamond to glass

    Energy Technology Data Exchange (ETDEWEB)

    Fuentes, R. [Materials and Technologies Corp., Poughkeepsie, NY (United States); Trolio, L.M. [Geo-Centers, Inc., Fort Washington, MD (United States); Butler, J.E. [Naval Research Lab., Washington, DC (United States)

    1995-12-31

    A method is described for anodically bonding smooth nanocrystalline diamond films to glass substrates to form extremely flat diamond membranes with the smoothest side available of patterning absorber structures to form masks for proximity focused x-ray lithography.

  13. A new route to process diamond wires

    Directory of Open Access Journals (Sweden)

    Marcello Filgueira

    2003-06-01

    Full Text Available We propose an original route to process diamond wires, denominated In Situ Technology, whose fabrication involves mechanical conformation processes, such as rotary forging, copper tubes restacking, and thermal treatments, such as sintering and recrystallisation of a bronze 4 wt.% diamond composite. Tensile tests were performed, reaching an ultimate tensile strength (UTS of 230 MPa for the diameter of Æ = 1.84 mm. Scanning electron microscopy showed the diamond crystals distribution along the composite rope during its manufacture, as well as the diamond adhesion to the bronze matrix. Cutting tests were carried out with the processed wire, showing a probable performance 4 times higher than the diamond sawing discs, however its probable performance was about 5 to 8 times less than the conventional diamond wires (pearl system due to the low abrasion resistance of the bronze matrix, and low adhesion between the pair bronze-diamond due to the use of not metallised diamond single crystals.

  14. CVD polymers fabrication of organic surfaces and devices

    CERN Document Server

    Gleason, Karen K

    2015-01-01

    The method of CVD (chemical vapor deposition) is a versatile technique to fabricate high-quality thin films and structured surfaces in the nanometer regime from the vapor phase. Already widely used for the deposition of inorganic materials in the semiconductor industry, CVD has become the method of choice in many applications to process polymers as well. This highly scalable technique allows for synthesizing high-purity, defect-free films and for systematically tuning their chemical, mechanical and physical properties. In addition, vapor phase processing is critical for the deposition of insol

  15. Ohmic contacts to semiconducting diamond

    Science.gov (United States)

    Zeidler, James R.; Taylor, M. J.; Zeisse, Carl R.; Hewett, C. A.; Delahoussaye, Paul R.

    1990-10-01

    Work was carried out to improve the electron beam evaporation system in order to achieve better deposited films. The basic system is an ion pumped vacuum chamber, with a three-hearth, single-gun e-beam evaporator. Four improvements were made to the system. The system was thoroughly cleaned and new ion pump elements, an e-gun beam adjust unit, and a more accurate crystal monitor were installed. The system now has a base pressure of 3 X 10(exp -9) Torr, and can easily deposit high-melting-temperature metals such as Ta with an accurately controlled thickness. Improved shadow masks were also fabricated for better alignment and control of corner contacts for electrical transport measurements. Appendices include: A Thermally Activated Solid State Reaction Process for Fabricating Ohmic Contacts to Semiconducting Diamond; Tantalum Ohmic Contacts to Diamond by a Solid State Reaction Process; Metallization of Semiconducting Diamond: Mo, Mo/Au, and Mo/Ni/Au; Specific Contact Resistance Measurements of Ohmic Contracts to Diamond; and Electrical Activation of Boron Implanted into Diamond.

  16. Development of Diamond-Coated Drills

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Compared with the sintered polycrystalline diamond, the deposited thin film diamond has the great advantage on the fabrication of cutting tools with complex geometries such as drills. Because of their low costs for fabrication equipment and high performance on high speed machining non-ferrous metals and alloys, metal-compound materials, and hard brittle non-metals, diamond-coated drills find great potentialities in the commercial application. However, the poor adhesion of the diamond film on the substrate...

  17. Raman spectral research on MPCVD diamond film

    Institute of Scientific and Technical Information of China (English)

    YAN Yan; ZHANG Shulin; ZHAO Xinsheng; HAN Yisong; HOU Li

    2003-01-01

    Raman spectra of MPCVD diamond film have been studied. Based on the resonance size selection effect, we think that there is no nano-crystalline diamond in the sample and the Raman peak at 1145 cm-1 can not be considered as the characteristic peak of nano-crystalline diamond though it has been used as the characteristic peak of nano-crystalline diamond widely for many years.

  18. Medical applications of diamond particles & surfaces

    Directory of Open Access Journals (Sweden)

    Roger J Narayan

    2011-04-01

    Full Text Available Diamond has been considered for use in several medical applications due to its unique mechanical, chemical, optical, and biological properties. In this paper, methods for preparing synthetic diamond surfaces and particles are described. In addition, recent developments involving the use of diamond in prostheses, sensing, imaging, and drug delivery applications are reviewed. These developments suggest that diamond-containing structures will provide significant improvements in the diagnosis and treatment of medical conditions over the coming years.

  19. Diamond and diamond-like films for transportation applications

    Energy Technology Data Exchange (ETDEWEB)

    Perez, J.M.

    1993-01-01

    This section is a compilation of transparency templates which describe the goals of the Office of Transportation Materials (OTM) Tribology Program. The positions of personnel on the OTM are listed. The role and mission of the OTM is reviewed. The purpose of the Tribology Program is stated to be `to obtain industry input on program(s) in tribology/advanced lubricants areas of interest`. The objective addressed here is to identify opportunities for cost effective application of diamond and diamond-like carbon in transportation systems.

  20. Diamond Drilling Specification Manual and Course Outline.

    Science.gov (United States)

    British Columbia Dept. of Education, Victoria.

    This publication presents the standards required of a person practicing diamond drilling in western Canada and provides an outline for teaching the skills and knowledge. It is divided into two parts. The Diamond Drilling Specification Manual establishes the levels of skill and knowledge required in the four certified levels of diamond drilling.…

  1. Diamonds at the golden point

    CERN Multimedia

    Katarina Anthony

    2015-01-01

    Alongside the CMS Pixel Luminosity Telescope (PLT) – installed last month (see here) – lie diamond detectors. No ordinary gems, these lab-grown diamonds will be playing a vital role in Run 2: differentiating signals from collision products with those from the beam background.   The BCM detector's green "c-shaped" printed circuit board is mounted on the PLT/BCM carbon-fibre carriage ready for installation. Earlier this year, the CMS BRIL project installed beam condition monitors (BCM) at the heart of the CMS detector. Designed to measure the online luminosity and beam background as close as possible to the LHC beam pipe, the BCMs use radiation-hard diamonds to differentiate between background and collision signals. The BCM also protects the CMS silicon trackers from damaging beam losses, by aborting the beam if the signal currents measured are above an acceptable threshold. These new BCMs are designed with Run 2 bunches in mind. &ldq...

  2. Pulsed laser deposition of metallic films on the surface of diamond particles for diamond saw blades

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Chao [State Key Laboratory of Laser Technology, Huazhong University of Science and Technology, WuHan, Hubei 430074 (China); Luo Fei [State Key Laboratory of Laser Technology, Huazhong University of Science and Technology, WuHan, HuBei 430074 (China); Long Hua [State Key Laboratory of Laser Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Hu Shaoliu [State Key Laboratory of Laser Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Li Bo [State Key Laboratory of Laser Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Wang Youqing [State Key Laboratory of Laser Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China)]. E-mail: lchwan@hust.edu.cn

    2005-06-15

    Ti or Ni films have been deposited on the diamond particle surfaces by pulsed laser deposition. Compressive resistance of the uncoated and coated diamond particles was measured, respectively, in the experiments. The compressive resistance of the Ti-coated diamonds particles was found much higher than that of the uncoated ones. It increased by 39%. The surface morphology is observed by the metallography microscope. The surface of the uncoated diamonds particles had many hollows and flaws, while the surface of Ni-coated diamond particles was flat and smooth, and the surface of Ti-coated diamond particles had some metal masses that stood out of the surface of the Ti-coated film. The components of the metallic films of diamond particles were examined by X-ray diffractometry (XRD). TiC was found formed on the Ti-coated diamond surface, which resulted in increased surface bonding strength between the diamond particles and the Ti films. Meanwhile, TiC also favored improving the bonding strength between the coated diamond particles and the binding materials. Moreover, the bending resistance of the diamond saw blade made of Ti-coated diamond was drastically higher than that of other diamond saw blades, which also played an important role in improving the blade's cutting ability and lifetime. Therefore, it was most appropriate that the diamond saw blade was made of Ti-coated diamond particles rather than other materials.

  3. Diamonds on Diamond: structural studies at extreme conditions on the Diamond Light Source.

    Science.gov (United States)

    McMahon, M I

    2015-03-06

    Extreme conditions (EC) research investigates how the structures and physical and chemical properties of materials change when subjected to extremes of pressure and temperature. Pressures in excess of one million times atmospheric pressure can be achieved using a diamond anvil cell, and, in combination with high-energy, micro-focused radiation from a third-generation synchrotron such as Diamond, detailed structural information can be obtained using either powder or single-crystal diffraction techniques. Here, I summarize some of the research drivers behind international EC research, and then briefly describe the techniques by which high-quality diffraction data are obtained. I then highlight the breadth of EC research possible on Diamond by summarizing four examples from work conducted on the I15 and I19 beamlines, including a study which resulted in the first research paper from Diamond. Finally, I look to the future, and speculate as to the type of EC research might be conducted at Diamond over the next 10 years.

  4. Atmospheric pressure CVD of SNO2 and ZNO:AL

    NARCIS (Netherlands)

    Deelen, J. van; Kniknie, B.J.; Steijvers, H.L.A.H.; Mannie, G.; Thune, P.; Illiberi, A.

    2012-01-01

    Atmospheric pressure CVD (APCVD) is a highly cost effective method of depositing transparent conductive oxides (TCOs). In this work, insights in alcohol addition in the widely applied SnO2 process are discussed, including high resolution TEM images. Furthermore, the APCVD process of ZnO:Al was demon

  5. Diamond Heat-Spreader for Submillimeter-Wave Frequency Multipliers

    Science.gov (United States)

    Lin, Robert H.; Schlecht, Erich T.; Chattopadhyay, Goutam; Gill, John J.; Mehdi, Imran; Siegel, Peter H.; Ward, John S.; Lee, Choonsup; Thomas, Bertrand C.; Maestrini, Alain

    2010-01-01

    The planar GaAs Shottky diode frequency multiplier is a critical technology for the local oscillator (LO) for submillimeter- wave heterodyne receivers due to low mass, tenability, long lifetime, and room-temperature operation. The use of a W-band (75-100 GHz) power amplifier followed by a frequency multiplier is the most common for submillimeter-wave sources. Its greatest challenge is to provide enough input power to the LO for instruments onboard future planetary missions. Recently, JPL produced 800 mW at 92.5 GHz by combining four MMICs in parallel in a balanced configuration. As more power at W-band is available to the multipliers, their power-handling capability be comes more important. High operating temperatures can lead to degradation of conversion efficiency or catastrophic failure. The goal of this innovation is to reduce the thermal resistance by attaching diamond film as a heat-spreader on the backside of multipliers to improve their power-handling capability. Polycrystalline diamond is deposited by hot-filament chemical vapor deposition (CVD). This diamond film acts as a heat-spreader to both the existing 250- and 300-GHz triplers, and has a high thermal conductivity (1,000-1,200 W/mK). It is approximately 2.5 times greater than copper (401 W/mK) and 20 times greater than GaAs (46 W/mK). It is an electrical insulator (resistivity approx. equals 10(exp 15) Ohms-cm), and has a low relative dielectric constant of 5.7. Diamond heat-spreaders reduce by at least 200 C at 250 mW of input power, compared to the tripler without diamond, according to thermal simulation. This superior thermal management provides a 100-percent increase in power-handling capability. For example, with this innovation, 40-mW output power has been achieved from a 250-GHz tripler at 350-mW input power, while the previous triplers, without diamond, suffered catastrophic failures. This breakthrough provides a stepping-stone for frequency multipliers-based LO up to 3 THz. The future work

  6. Method for machining steel with diamond tools

    Science.gov (United States)

    Casstevens, John M.

    1986-01-01

    The present invention is directed to a method for machining optical quality inishes and contour accuracies of workpieces of carbon-containing metals such as steel with diamond tooling. The wear rate of the diamond tooling is significantly reduced by saturating the atmosphere at the interface of the workpiece and the diamond tool with a gaseous hydrocarbon during the machining operation. The presence of the gaseous hydrocarbon effectively eliminates the deterioration of the diamond tool by inhibiting or preventing the conversion of the diamond carbon to graphite carbon at the point of contact between the cutting tool and the workpiece.

  7. Diamond Sensors for Energy Frontier Experiments

    CERN Document Server

    Schnetzer, Steve

    2014-01-01

    We discuss the use of diamond sensors in high-energy, high-i ntensity collider experiments. Re- sults from diamond sensor based beam conditions monitors in the ATLAS and CMS experiments at the CERN Large Hadron Collider (LHC) are presented and pla ns for diamond based luminosity monitors for the upcoming LHC run are described. We describe recent measurements on single crystal diamond sensors that indicate a polarization effec t that causes a reduction of charge col- lection efficiency as a function of particle flux. We conclude by describing new developments on the promising technology of 3D diamond sensors.

  8. Nanocrystalline diamond films for biomedical applications

    DEFF Research Database (Denmark)

    Pennisi, Cristian Pablo; Alcaide, Maria

    2014-01-01

    performance of nanocrystalline diamond films is reviewed from an application-specific perspective, covering topics such as enhancement of cellular adhesion, anti-fouling coatings, non-thrombogenic surfaces, micropatterning of cells and proteins, and immobilization of biomolecules for bioassays. In order......Nanocrystalline diamond films, which comprise the so called nanocrystalline diamond (NCD) and ultrananocrystalline diamond (UNCD), represent a class of biomaterials possessing outstanding mechanical, tribological, and electrical properties, which include high surface smoothness, high corrosion...... resistance, chemical inertness, superior electrochemical behavior, biocompatibility, and nontoxicity. These properties have positioned the nanocrystalline diamond films as an attractive class of materials for a range of therapeutic and diagnostic applications in the biomedical field. Consequently...

  9. Transparent nanocrystalline diamond coatings and devices

    Energy Technology Data Exchange (ETDEWEB)

    Sumant, Anirudha V.; Khan, Adam

    2017-08-22

    A method for coating a substrate comprises producing a plasma ball using a microwave plasma source in the presence of a mixture of gases. The plasma ball has a diameter. The plasma ball is disposed at a first distance from the substrate and the substrate is maintained at a first temperature. The plasma ball is maintained at the first distance from the substrate, and a diamond coating is deposited on the substrate. The diamond coating has a thickness. Furthermore, the diamond coating has an optical transparency of greater than about 80%. The diamond coating can include nanocrystalline diamond. The microwave plasma source can have a frequency of about 915 MHz.

  10. Electron Microscopy of Natural and Epitaxial Diamond

    Science.gov (United States)

    Posthill, J. B.; George, T.; Malta, D. P.; Humphreys, T. P.; Rudder, R. A.; Hudson, G. C.; Thomas, R. E.; Markunas, R. J.

    1993-01-01

    Semiconducting diamond films have the potential for use as a material in which to build active electronic devices capable of operating at high temperatures or in high radiation environments. Ultimately, it is preferable to use low-defect-density single crystal diamond for device fabrication. We have previously investigated polycrystalline diamond films with transmission electron microscopy (TEM) and scanning electron microscopy (SEM), and homoepitaxial films with SEM-based techniques. This contribution describes some of our most recent observations of the microstructure of natural diamond single crystals and homoepitaxial diamond thin films using TEM.

  11. Selected Bibliography II-Diamond Surface Chemistry

    Science.gov (United States)

    1993-09-30

    34Scanning Tunneling Microscopy of Polished Diamond Surfaces" JNL: Appl. Surf. Sci. REF: 62(4) (1992) 263-8 91 AUTHOR: Vazquez L., Martin -Gago J. A...Absorption in Semiconducting Synthetic Diamond" JNL: Physical Review REF: 140 (1965) A1272 AUTHOR: Keown R. TITLE: "Energy Bands in Diamond" JNL...34Determination of Optical Constant of Diamond Thin Films" JNL: Proc. SPIE-Int. Soc. Opt. Eng. REF: 1759(Diamond Opt. V) (1992) 218-23 AUTHOR: Fazzio A., Martins

  12. Diamond Ablators for Inertial Confinement Fusion

    Energy Technology Data Exchange (ETDEWEB)

    Biener, J; Mirkarimi, P B; Tringe, J W; Baker, S L; Wang, Y M; Kucheyev, S O; Teslich, N E; Wu, K J; Hamza, A V; Wild, C; Woerner, E; Koidl, P; Bruehne, K; Fecht, H

    2005-06-21

    Diamond has a unique combination of physical properties for the inertial confinement fusion ablator application, such as appropriate optical properties, high atomic density, high yield strength, and high thermal conductivity. Here, we present a feasible concept to fabricate diamond ablator shells. The fabrication of diamond capsules is a multi-step process, which involves diamond chemical vapor deposition on silicon mandrels followed by polishing, microfabrication of holes, and removing of the silicon mandrel by an etch process. We also discuss the pros and cons of coarse-grained optical quality and nanocrystalline chemical vapor deposition diamond films for the ablator application.

  13. Dentinal surface-cutting efficiency using a high-speed diamond bur, ultrasound and laser

    Science.gov (United States)

    Youssef, M.; Quinelato, A.; Youssef, F.; Pelino, J. E. Pelizon; Salvadori, M. C.; Mori, M.

    2008-04-01

    We compare an ultrasound bur with a conventional one and an Er:YAG laser for cavity preparations. Human molars were embedded in resin and sliced for this study. The surface abrasion was performed by a high-speed instrument and ultrasound. The cavity preparation was initially performed with a high-speed diamond bur. After this, a 2.94-μm laser with 400 mJ/pulse at 4 Hz, and a pulse width from 250-500 μs was applied to the tooth surface for 30 s in a sweeping motion. The samples were analyzed by SEM. The abrasion surface with a conventional bur showed structure removal with different grooves, a smear-layer presence, and occluded dentinal tubules. The abraded surface with the CVD bur suggested a removal process in layers. The laser-irradiated surface showed a rough aspect with opened tubules and the absence of a smear layer. The results of this study suggest that a high-speed diamond bur, ultrasound, and laser were able to perform cavity preparation. However, the CVD bur presented a higher surface quality.

  14. Microplasma device architectures with various diamond nanostructures

    Science.gov (United States)

    Kunuku, Srinivasu; Jothiramalingam Sankaran, Kamatchi; Leou, Keh-Chyang; Lin, I.-Nan

    2017-02-01

    Diamond nanostructures (DNSs) were fabricated from three different morphological diamonds, microcrystalline diamond (MCD), nanocrystalline diamond (NCD), and ultrananocrystalline diamond (UNCD) films, using a reactive ion etching method. The plasma illumination (PI) behavior of microplasma devices using the DNSs and the diamond films as cathode were investigated. The Paschen curve approach revealed that the secondary electron emission coefficient (γ value) of diamond materials is similar irrespective of the microstructure (MCD, NCD, and UNCD) and geometry of the materials (DNSs and diamond films). The diamond materials show markedly larger γ-coefficient than conventional metallic cathode materials such as Mo that resulted in markedly better PI behavior for the corresponding microplasma devices. Moreover, the PI behavior, i.e. the voltage dependence of plasma current density (J pl‑V), plasma density (n e‑V), and the robustness of the devices, varied markedly with the microstructure and geometry of the cathode materials that was closely correlated to the electron field emission (EFE) properties of the cathode materials. The UNCD nanopillars, possessing good EFE properties, resulted in superior PI behavior, whereas the MCD diamond films with insufficient EFE properties led to inferior PI behavior. Consequently, enhancement of plasma characteristics is the collective effects of EFE behavior and secondary electron emission characteristics of diamond-based cathode materials.

  15. Effects of diamond magnetism on the microstructure of electrodeposited diamond composites

    Institute of Scientific and Technical Information of China (English)

    Lu Huiyang; Li Yundong; Huang Zhiwei; Go Huiyan

    2007-01-01

    Electroformed diamond tools have been used for many years in grinding and cutting fields while electrodeposited diamond composite coatings have been widely studied due to their desirable hardness, wear and corrosion resistance. This article eports the detrimental impact of diamond magnetism on the composites microstructure and gives explanations. Microstructure differences between composites that, respectively, contained no - further - treated diamond, magnetism - strengthening treated diamond and magnetism weakening treated diamond were carefully observed. It is shown that diamond magnetization treatment drastically harms the composite microstructure (e. G. , roughening the coating surface, coarsening the matrix grain, and more seriously, reducing the mechanical retention of diamond grains in the matrix) while demagnetization treatment does the opposite. All the observed facts could be explained by the electromagnetic interaction between magnetic fields produced by magnetic diamond grains and electric current (moving cations) during the electrodeposition process.

  16. High temperature brazing of diamond tools

    Institute of Scientific and Technical Information of China (English)

    YAO Zheng-jun; SU Hong-hua; FU Yu-can; XU Hong-jun

    2005-01-01

    A new brazing technique of diamond was developed. Using this new technique optimum chemical and metallurgical bonding between the diamond grits and the carbon steel can be achieved without any thermal damages to diamond grits. The results of microanalysis and X-ray diffraction analysis reveal that a carbide layer exists between the diamond and the matrix, which consists of Cr3C2, Cr7C3 and Cr23C6. Performance tests show that the brazed diamond core-drill has excellent machining performance. In comparison with traditional electroplated diamond core-drill, the brazed diamond core-drill manufactured using the new developed technique has much higher machining efficiency and much longer operating life.

  17. Designing shallow donors in diamond

    Science.gov (United States)

    Moussa, Jonathan

    2015-03-01

    The production of n-type semiconducting diamond has been a long-standing experimental challenge. The first-principles simulation of shallow dopants in semiconductors has been a long-standing theoretical challenge. A desirable theoretical goal is to identify impurities that will act as shallow donors in diamond and assess their experimental viability. I will discuss this identification process for the LiN4 donor complex. It builds a scientific argument from several models and computational results in the absence of computational tools that are both trustworthy and computationally tractable for this task. I will compare the theoretical assessment of viability with recent experimental efforts to co-dope diamond with lithium and nitrogen. Finally, I discuss the computational tools needed to facilitate future work on this problem and some preliminary simulations of donors near diamond surfaces. Sandia National Laboratories is a multi-program lab managed and operated by Sandia Corp., a wholly owned subsidiary of Lockheed Martin Corp., for the U.S. Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  18. On a remarkable composite Diamond

    NARCIS (Netherlands)

    Escher, B.G.

    1942-01-01

    In June 1937 the State Museum of Geology and Mineralogy at Leiden received from Mr. A.S. Dresden at Amsterdam a diamond crystal of a hitherto unknown shape. The crystal is colourless and transparent. Mr. J. Bolman determined its weight at 0.1698 g and its specific gravity at 3.4165.

  19. Changes in CVD risk factors in the activity counseling trial

    Directory of Open Access Journals (Sweden)

    Meghan Baruth

    2011-01-01

    Full Text Available Meghan Baruth1, Sara Wilcox1, James F Sallis3, Abby C King4,5, Bess H Marcus6, Steven N Blair1,21Department of Exercise Science, 2Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Public Health Research Center, Columbia, SC, USA; 3Department of Psychology, San Diego State University, San Diego, CA, USA; 4Department of Health Research and Policy, 5Stanford Prevention Research Center, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA; 6Behavioral and Social Sciences Section, Brown University Program in Public Health, Providence, RI, USAAbstract: Primary care facilities may be a natural setting for delivering interventions that focus on behaviors that improve cardiovascular disease (CVD risk factors. The purpose of this study was to examine the 24-month effects of the Activity Counseling Trial (ACT on CVD risk factors, to examine whether changes in CVD risk factors differed according to baseline risk factor status, and to examine whether changes in fitness were associated with changes in CVD risk factors. ACT was a 24-month multicenter randomized controlled trial to increase physical activity. Participants were 874 inactive men and women aged 35–74 years. Participants were randomly assigned to one of three arms that varied by level of counseling, intensity, and resource requirements. Because there were no significant differences in change over time between arms on any of the CVD risk factors examined, all arms were combined, and the effects of time, independent of arm, were examined separately for men and women. Time × Baseline risk factor status interactions examined whether changes in CVD risk factors differed according to baseline risk factor status. Significant improvements in total cholesterol, high-density lipoprotein cholesterol (HDL-C and low-density lipoprotein cholesterol, the ratio of total cholesterol to HDL-C, and triglycerides were seen in

  20. Electroluminescence from a diamond device with ion-beam-micromachined buried graphitic electrodes

    Science.gov (United States)

    Forneris, J.; Battiato, A.; Gatto Monticone, D.; Picollo, F.; Amato, G.; Boarino, L.; Brida, G.; Degiovanni, I. P.; Enrico, E.; Genovese, M.; Moreva, E.; Traina, P.; Verona, C.; Verona Rinati, G.; Olivero, P.

    2015-04-01

    Focused MeV ion microbeams are suitable tools for the direct writing of conductive graphitic channels buried in an insulating diamond bulk, as demonstrated in previous works with the fabrication of multi-electrode ionizing radiation detectors and cellular biosensors. In this work we investigate the suitability of the fabrication method for the electrical excitation of color centers in diamond. Differently from photoluminescence, electroluminescence requires an electrical current flowing through the diamond sub-gap states for the excitation of the color centers. With this purpose, buried graphitic electrodes with a spacing of 10 μm were fabricated in the bulk of a detector-grade CVD single-crystal diamond sample using a scanning 1.8 MeV He+ micro-beam. The current flowing in the gap region between the electrodes upon the application of a 450 V bias voltage was exploited as the excitation pump for the electroluminescence of different types of color centers localized in the above-mentioned gap. The bright light emission was spatially mapped using a confocal optical microscopy setup. The spectral analysis of electroluminescence revealed the emission from neutrally-charged nitrogen-vacancy centers (NV0, λZPL = 575 nm), as well as from cluster crystal dislocations (A-band, λ = 400-500 nm). Moreover, an electroluminescence signal with appealing spectral features (sharp emission at room temperature, low phonon sidebands) from He-related defects was detected (λZPL = 536.3 nm, λZPL = 560.5 nm); a low and broad peak around λ = 740 nm was also observed and tentatively ascribed to Si-V or GR1 centers. These results pose interesting future perspectives for the fabrication of electrically-stimulated single-photon emitters in diamond for applications in quantum optics and quantum cryptography.

  1. Electroluminescence from a diamond device with ion-beam-micromachined buried graphitic electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Forneris, J., E-mail: jacopo.forneris@unito.it [Physics Department and NIS Interdepartmental Centre, University of Torino, Torino (Italy); Istituto Nazionale di Fisica Nucleare (INFN), Sez. Torino, Torino (Italy); Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM), Sez. Torino, Torino (Italy); Battiato, A.; Gatto Monticone, D. [Physics Department and NIS Interdepartmental Centre, University of Torino, Torino (Italy); Istituto Nazionale di Fisica Nucleare (INFN), Sez. Torino, Torino (Italy); Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM), Sez. Torino, Torino (Italy); Picollo, F. [Istituto Nazionale di Fisica Nucleare (INFN), Sez. Torino, Torino (Italy); Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM), Sez. Torino, Torino (Italy); Physics Department and NIS Interdepartmental Centre, University of Torino, Torino (Italy); Amato, G.; Boarino, L.; Brida, G.; Degiovanni, I.P.; Enrico, E.; Genovese, M.; Moreva, E.; Traina, P. [Istituto Nazionale di Ricerca Metrologica (INRiM), Torino (Italy); Verona, C.; Verona Rinati, G. [Department of Industrial Engineering, University of Roma “Tor Vergata”, Roma (Italy); Olivero, P. [Physics Department and NIS Interdepartmental Centre, University of Torino, Torino (Italy); Istituto Nazionale di Fisica Nucleare (INFN), Sez. Torino, Torino (Italy); Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM), Sez. Torino, Torino (Italy)

    2015-04-01

    Focused MeV ion microbeams are suitable tools for the direct writing of conductive graphitic channels buried in an insulating diamond bulk, as demonstrated in previous works with the fabrication of multi-electrode ionizing radiation detectors and cellular biosensors. In this work we investigate the suitability of the fabrication method for the electrical excitation of color centers in diamond. Differently from photoluminescence, electroluminescence requires an electrical current flowing through the diamond sub-gap states for the excitation of the color centers. With this purpose, buried graphitic electrodes with a spacing of 10 μm were fabricated in the bulk of a detector-grade CVD single-crystal diamond sample using a scanning 1.8 MeV He{sup +} micro-beam. The current flowing in the gap region between the electrodes upon the application of a 450 V bias voltage was exploited as the excitation pump for the electroluminescence of different types of color centers localized in the above-mentioned gap. The bright light emission was spatially mapped using a confocal optical microscopy setup. The spectral analysis of electroluminescence revealed the emission from neutrally-charged nitrogen-vacancy centers (NV{sup 0}, λ{sub ZPL} = 575 nm), as well as from cluster crystal dislocations (A-band, λ = 400–500 nm). Moreover, an electroluminescence signal with appealing spectral features (sharp emission at room temperature, low phonon sidebands) from He-related defects was detected (λ{sub ZPL} = 536.3 nm, λ{sub ZPL} = 560.5 nm); a low and broad peak around λ = 740 nm was also observed and tentatively ascribed to Si-V or GR1 centers. These results pose interesting future perspectives for the fabrication of electrically-stimulated single-photon emitters in diamond for applications in quantum optics and quantum cryptography.

  2. Artificial diamonds as radiation-hard detectors for ultra-fast fission-fragment timing

    Energy Technology Data Exchange (ETDEWEB)

    Oberstedt, S., E-mail: stephan.oberstedt@ec.europa.eu [European Commission, DG Joint Research Centre (IRMM), B-2440 Geel (Belgium); Borcea, R.; Bryś, T.; Gamboni, Th.; Geerts, W.; Hambsch, F.-J. [European Commission, DG Joint Research Centre (IRMM), B-2440 Geel (Belgium); Oberstedt, A. [Fundamental Fysik, Chalmers Tekniska Högskola, S-41296 Göteborg (Sweden); Akademin för Naturvetenskap och Technik, Örebro Universitet, S-70182 Örebro (Sweden); Vidali, M. [European Commission, DG Joint Research Centre (IRMM), B-2440 Geel (Belgium)

    2013-06-21

    In the framework of the construction of the double time-of-flight spectrometer VERDI, where we aim at measuring pre- and post-neutron masses directly and simultaneously, ultra-fast time pick-up detectors based on artificial diamond material were investigated for the first time with fission fragments from {sup 252}Cf (0.5MeV/udiamond material with a strong β-source for about 48 h. The intrinsic timing resolution of a 100μm thick polycrystalline CVD diamond detector with a size of 1×1 cm{sup 2} was determined to σ{sub int}=(283±41)ps by comparison with Monte-Carlo simulations. Using broadband pre-amplifiers, 4-fold segmented detectors of same total size and with a thickness of 180μm show an intrinsic timing resolution of σ{sub int}=(106±21)ps. This is highly competitive with the best micro-channel plate detectors. Due to the limited and batch-dependent charge collection efficiency of poly-crystalline diamond material, the detection efficiency for fission fragments may be smaller than 100%. -- Highlights: ► First use of chemical vapor deposited diamond for heavy ions with kinetic energies below 2 MeV per nucleon. ► Fission-fragment time-of-flight measurements with a timing resolution better than 150 ps. ► Radiation-hard fission event trigger to be used in an intense neutron field.

  3. Diamond xenolith and matrix organic matter in the Sutter's Mill meteorite measured by C-XANES

    Science.gov (United States)

    Kebukawa, Yoko; Zolensky, Michael E.; Kilcoyne, A. L. David; Rahman, Zia; Jenniskens, Peter; Cody, George D.

    2014-11-01

    The Sutter's Mill (SM) meteorite fell in El Dorado County, California, on April 22, 2012. This meteorite is a regolith breccia composed of CM chondrite material and at least one xenolithic phase: oldhamite. The meteorite studied here, SM2 (subsample 5), was one of three meteorites collected before it rained extensively on the debris site, thus preserving the original asteroid regolith mineralogy. Two relatively large (10 μm sized) possible diamond grains were observed in SM2-5 surrounded by fine-grained matrix. In the present work, we analyzed a focused ion beam (FIB) milled thin section that transected a region containing these two potential diamond grains as well as the surrounding fine-grained matrix employing carbon and nitrogen X-ray absorption near-edge structure (C-XANES and N-XANES) spectroscopy using a scanning transmission X-ray microscope (STXM) (Beamline 5.3.2 at the Advanced Light Source, Lawrence Berkeley National Laboratory). The STXM analysis revealed that the matrix of SM2-5 contains C-rich grains, possibly organic nanoglobules. A single carbonate grain was also detected. The C-XANES spectrum of the matrix is similar to that of insoluble organic matter (IOM) found in other CM chondrites. However, no significant nitrogen-bearing functional groups were observed with N-XANES. One of the possible diamond grains contains a Ca-bearing inclusion that is not carbonate. C-XANES features of the diamond-edges suggest that the diamond might have formed by the CVD process, or in a high-temperature and -pressure environment in the interior of a much larger parent body.

  4. Diamond/diamond-like carbon coated nanotube structures for efficient electron field emission

    Science.gov (United States)

    Dimitrijevic, Steven (Inventor); Withers, James C. (Inventor); Loutfy, Raouf O. (Inventor)

    2005-01-01

    The present invention is directed to a nanotube coated with diamond or diamond-like carbon, a field emitter cathode comprising same, and a field emitter comprising the cathode. It is also directed to a method of preventing the evaporation of carbon from a field emitter comprising a cathode comprised of nanotubes by coating the nanotube with diamond or diamond-like carbon. In another aspect, the present invention is directed to a method of preventing the evaporation of carbon from an electron field emitter comprising a cathode comprised of nanotubes, which method comprises coating the nanotubes with diamond or diamond-like carbon.

  5. Diamond-modified AFM probes: from diamond nanowires to atomic force microscopy-integrated boron-doped diamond electrodes.

    Science.gov (United States)

    Smirnov, Waldemar; Kriele, Armin; Hoffmann, René; Sillero, Eugenio; Hees, Jakob; Williams, Oliver A; Yang, Nianjun; Kranz, Christine; Nebel, Christoph E

    2011-06-15

    In atomic force microscopy (AFM), sharp and wear-resistant tips are a critical issue. Regarding scanning electrochemical microscopy (SECM), electrodes are required to be mechanically and chemically stable. Diamond is the perfect candidate for both AFM probes as well as for electrode materials if doped, due to diamond's unrivaled mechanical, chemical, and electrochemical properties. In this study, standard AFM tips were overgrown with typically 300 nm thick nanocrystalline diamond (NCD) layers and modified to obtain ultra sharp diamond nanowire-based AFM probes and probes that were used for combined AFM-SECM measurements based on integrated boron-doped conductive diamond electrodes. Analysis of the resonance properties of the diamond overgrown AFM cantilevers showed increasing resonance frequencies with increasing diamond coating thicknesses (i.e., from 160 to 260 kHz). The measured data were compared to performed simulations and show excellent correlation. A strong enhancement of the quality factor upon overgrowth was also observed (120 to 710). AFM tips with integrated diamond nanowires are shown to have apex radii as small as 5 nm and where fabricated by selectively etching diamond in a plasma etching process using self-organized metal nanomasks. These scanning tips showed superior imaging performance as compared to standard Si-tips or commercially available diamond-coated tips. The high imaging resolution and low tip wear are demonstrated using tapping and contact mode AFM measurements by imaging ultra hard substrates and DNA. Furthermore, AFM probes were coated with conductive boron-doped and insulating diamond layers to achieve bifunctional AFM-SECM probes. For this, focused ion beam (FIB) technology was used to expose the boron-doped diamond as a recessed electrode near the apex of the scanning tip. Such a modified probe was used to perform proof-of-concept AFM-SECM measurements. The results show that high-quality diamond probes can be fabricated, which are

  6. Precise control of photoluminescence of silicon-vacancy color centers in homoepitaxial single-crystal diamond: evaluation of efficiency of Si doping from gas phase

    Science.gov (United States)

    Ralchenko, Victor; Sedov, Vadim; Saraykin, Vladimir; Bolshakov, Andrey; Zavedeev, Evgeny; Ashkinazi, Evgeny; Khomich, Andrew

    2016-09-01

    Ability to precisely control the Si-related color center abundance in diamond is important for the use of silicon-vacancy (SiV) defects with bright photoluminescence (PL) in quantum information technologies and optical biomarkers. Here, we evaluated the efficiency of Si incorporation in (100) plane of homoepitaxial diamond layers upon in situ doping by adding silane SiH4 in the course of diamond chemical vapor deposition in microwave plasma using CH4-H2 mixtures. Both the Si concentration in the doped samples, as determined by secondary ion mass spectrometry, and PL intensity of SiV centers at 738 nm wavelength, measured at excitation wavelength of 473 nm, demonstrate a linear increase with silane content in feed gas in the range. The incorporation efficiency f, defined as the ratio of Si concentration in diamond to that in gas, f = [Si/C]dia/[Si/C]gas is found to be (1.1 ± 0.5) × 10-3 for the silane concentrations explored, [SiH4/CH4] < 0.7 %; thus, the Si atoms are accommodated in (100) diamond face easier than nitrogen and phosphorus, but more difficult than boron. This finding allows a tailoring of the Si content and photoluminescence intensity of SiV centers in in situ doped CVD diamond.

  7. Freestanding single crystal chemical vapor deposited diamond films produced using a lift-off method: Response to {alpha}-particles from {sup 241}Am and crystallinity

    Energy Technology Data Exchange (ETDEWEB)

    Tsubouchi, Nobuteru, E-mail: nobu-tsubouchi@aist.go.jp [Diamond Research Laboratory, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577 (Japan); Mokuno, Y. [Diamond Research Laboratory, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577 (Japan); Kakimoto, A.; Fujita, F.; Kaneko, J.H. [Graduate School of Engineering, Hokkaido University, Sapporo 060-8628 (Japan); Yamada, H.; Chayahara, A.; Shikata, S. [Diamond Research Laboratory, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577 (Japan)

    2012-09-01

    Thick ({approx}100 {mu}m) undoped diamond films were grown homoepitaxially on single crystal (SC) diamond substrates by microwave plasma chemical vapor deposition (CVD). To form a freestanding SC diamond film (plate), the substrate was pre-ion-implanted with high-energy ion beams before the film growth, and after the thick-film deposition, the substrate was eliminated using a lift-off method, resulting in fabrication of a SC CVD diamond plate. Two samples were prepared; sample 1 was grown on a (0 0 1) oriented, nitrogen doped CVD SC diamond at {approx}900 Degree-Sign C with the input microwave power of 1.7 kW, while sample 2 was grown on a (0 0 1) oriented, high-pressure high-temperature synthesized type-Ib SC diamond at {approx}900 Degree-Sign C with the input microwave power of 1.25 kW. The formed SC plates have high optical transparencies, indicating no remarkable optical absorptions seen in the wavelength from ultraviolet to near infrared. The photoluminescence (PL) spectra of both samples show strong free exciton FE peaks, while in sample 2 relatively strong optical emissions corresponding to nitrogen related centers were observed in the visible region. After the metal electrodes were formed on both faces of the SC diamond plate to fabricate a sandwich-type diamond particle detector, the energy spectra of 5.486 MeV {alpha}-particles from {sup 241}Am were measured. The charge collection efficiencies (CCEs) of sample 1 were CCE = 98% for a hole transport and CCE = 89% for an electron transport, respectively, while CCEs of sample 2 were CCE = 80% for a hole transport and CCE = 78% for an electron transport, respectively. These results indicate that both holes and electrons in sample 2 were trapped much more than those in sample 1. Possible candidates of carrier capture centers are nitrogen and/or nitrogen-vacancy centers observed in PL, nonradiative defect (complex) centers, extended defects such as threading dislocations observed in micrographs taken with

  8. Argan oil improves surrogate markers of CVD in humans.

    Science.gov (United States)

    Sour, Souad; Belarbi, Meriem; Khaldi, Darine; Benmansour, Nassima; Sari, Nassima; Nani, Abdelhafid; Chemat, Farid; Visioli, Francesco

    2012-06-01

    Limited - though increasing - evidence suggests that argan oil might be endowed with potential healthful properties, mostly in the areas of CVD and prostate cancer. We sought to comprehensively determine the effects of argan oil supplementation on the plasma lipid profile and antioxidant status of a group of healthy Algerian subjects, compared with matched controls. A total of twenty healthy subjects consumed 15 g/d of argan oil - with toasted bread - for breakfast, during 4 weeks (intervention group), whereas twenty matched controls followed their habitual diet, but did not consume argan oil. The study lasted 30 d. At the end of the study, argan oil-supplemented subjects exhibited higher plasma vitamin E concentrations, lower total and LDL-cholesterol, lower TAG and improved plasma and cellular antioxidant profile, when compared with controls. In conclusion, we showed that Algerian argan oil is able to positively modulate some surrogate markers of CVD, through mechanisms which warrant further investigation.

  9. Catalytic CVD of SWCNTs at Low Temperatures and SWCNT Devices

    Science.gov (United States)

    Seidel, Robert; Liebau, Maik; Unger, Eugen; Graham, Andrew P.; Duesberg, Georg S.; Kreupl, Franz; Hoenlein, Wolfgang; Pompe, Wolfgang

    2004-09-01

    New results on the planar growth of single-walled carbon nanotubes (SWCNTs) by catalytic chemical vapor deposition (CVD) at low temperatures will be reported. Optimizing catalyst, catalyst support, and growth parameters yields SWCNTs at temperatures as low as 600 °C. Growth at such low temperatures largely affects the diameter distribution since coalescence of the catalyst is suppressed. A phenomenological growth model will be suggested for CVD growth at low temperatures. The model takes into account surface diffusion and is an alternative to the bulk diffusion based vapor-liquid-solid (VLS) model. Furthermore, carbon nanotubes field effect transistors based on substrate grown SWCNTs will be presented. In these devices good contact resistances could be achieved by electroless metal deposition or metal evaporation of the contacts.

  10. Cold Vacuum Drying (CVD) OCRWM Loop Error Determination

    Energy Technology Data Exchange (ETDEWEB)

    PHILIPP, B.L.

    2000-07-26

    Characterization is specifically identified by the Richland Operations Office (RL) for the Office of Civilian Radioactive Waste Management (OCRWM) of the US Department of Energy (DOE), as requiring application of the requirements in the Quality Assurance Requirements and Description (QARD) (RW-0333P DOE 1997a). Those analyses that provide information that is necessary for repository acceptance require application of the QARD. The cold vacuum drying (CVD) project identified the loops that measure, display, and record multi-canister overpack (MCO) vacuum pressure and Tempered Water (TW) temperature data as providing OCRWM data per Application of the Office of Civilian Radioactive Waste Management (OCRWM) Quality Assurance Requirements to the Hanford Spent Nuclear Fuel Project HNF-SD-SNF-RPT-007. Vacuum pressure transmitters (PT 1*08, 1*10) and TW temperature transmitters (TIT-3*05, 3*12) are used to verify drying and to determine the water content within the MCO after CVD.

  11. Electrochromic behavior in CVD grown tungsten oxide films

    Science.gov (United States)

    Gogova, D.; Iossifova, A.; Ivanova, T.; Dimitrova, Zl; Gesheva, K.

    1999-03-01

    Solid state electrochemical devices (ECDs) for smart windows, large area displays and automobile rearview mirrors are of considerable technological and commercial interest. In this paper, we studied the electrochromic properties of amorphous and polycrystalline CVD carbonyl tungsten oxide films and the possibility for sol-gel thin TiO 2 film to play the role of passive electrode in an electrochromic window with solid polymer electrolyte.

  12. Electrochromic behavior in CVD grown tungsten oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Gogova, D.; Iossifova, A.; Ivanova, T.; Gesheva, K.; Dimitrova, Z. [Central Laboratory for Solar Energy and New Energy Sources at Bulgarian Academy of Science, 72 Tzarigradsko shossee Blvd., Sofia (Bulgaria)

    1999-03-15

    Solid state electrochemical devices (ECDs) for smart windows, large area displays and automobile rearview mirrors are of considerable technological and commercial interest. In this paper, we studied the electrochromic properties of amorphous and polycrystalline CVD carbonyl tungsten oxide films and the possibility for sol-gel thinTiO{sub 2} film to play the role of passive electrode in an electrochromic window with solid polymer electrolyte

  13. THz-conductivity of CVD graphene on different substrates

    OpenAIRE

    Gabriel Cortés, Daniel; Sempere, Bernat; Colominas, Carles; Ferrer Anglada, Núria

    2015-01-01

    Optoelectronic properties of CVD graphene are charac-terized over a wide frequency range: THz, IR, visible and near-UV. We used Raman spectroscopy to characterize the synthesized graphene films. All graphene layers were deposited on various substrates, some ones transparent or flexible, such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), quartz and silicon. Transmission Terahertz time-domain spectroscopy (THz-TDS) method, in the range from 100 GHz to 3 THz, is used to an...

  14. Evidence relating sodium intake to blood pressure and CVD.

    Science.gov (United States)

    O'Donnell, Martin; Mente, Andrew; Yusuf, Salim

    2014-01-01

    Sodium is an essential nutrient, mostly ingested as salt (sodium chloride). Average sodium intake ranges from 3 to 6 g per day (7.5-15 g/day of salt) in most countries, with regional variations. Increasing levels of sodium intake have a positive association with higher blood pressure. Randomized controlled trials report a reduction in blood pressure with reducing sodium intake from moderate to low levels, which is the evidence that forms the basis for international guidelines recommending all people consume less than 2.0 g of sodium per day. However, no randomized trials have demonstrated that reducing sodium leads to a reduction in cardiovascular disease (CVD). In their absence, the next option is to examine the association between sodium consumption and CVD in prospective cohort studies. Several recent prospective cohort studies have indicated that while high intake of sodium (>6 g/d) is associated with higher risk of CVD compared to those with moderate intake (3 to 5 g/d), lower intake (<3 g/day) is also associated with a higher risk (despite lower blood pressure levels). However, most of these studies were conducted in populations at increased risk of cardiovascular disease. Current epidemiologic evidence supports that an optimal level of sodium intake is in the range of about 3-5 g/day, as this range is associated with lowest risk of CVD in prospective cohort studies. Randomized controlled trials, comparing the effect of low sodium intake to moderate intake on incidence of cardiovascular events and mortality, are required to truly define optimal intake range.

  15. Low-temperature deposition of transparent diamond films with a microwave cavity plasma reactor

    Science.gov (United States)

    Ulczynski, Michael J.

    1998-10-01

    Low-temperature diamond deposition with Microwave Cavity Plasma Reactor (MCPR) technology was investigated for application to temperature sensitive substrates. The substrate temperature during most CVD diamond deposition processes is typically greater then 600 C; however, there are some applications where temperature sensitive materials are used and the deposition temperature must be maintained below 550 C. These applications include materials like boro-silicate glass, which has a relatively low strain-point temperature, and integrated circuits that contain low melting point components. Experiments were conducted in three areas. The first area was MCPR development, the second was benchmark deposition and characterization of diamond films on silicon substrates and the third was deposition and characterization of diamond films on boro-silicate glass substrates. MCPR development included an investigation of various MCPR configurations that were designed and adapted for uniform, low-temperature diamond deposition over areas as large as 80-cm2. Reactors were investigated with end-feed microwave excitation and side-feed microwave excitation for maximum deposition area and uniformity. Various substrate receptor configurations were also investigated including a substrate heater and cooler. From these investigations, deposition parameters such as substrate temperature, deposition rate, deposition area and deposition uniformity were characterized. The benchmark silicon diamond deposition experiments were conducted for comparison to previous high temperature, >550 C, MCPR research and growth models. Here deposition results such as deposition rate and film quality were compared with applications of diamond growth models by Harris-Goodwin and Bachmann. Additionally, characterization experiments were conducted to investigate film attributes that are critical to optical applications, such as film surface roughness and deposition uniformity. Included as variables in these

  16. Infrared spectroscopic study of carrier scattering in gated CVD graphene

    Science.gov (United States)

    Yu, Kwangnam; Kim, Jiho; Kim, Joo Youn; Lee, Wonki; Hwang, Jun Yeon; Hwang, E. H.; Choi, E. J.

    2016-12-01

    We measured Drude absorption of gated CVD graphene using far-infrared transmission spectroscopy and determined the carrier scattering rate (γ ) as a function of the varied carrier density (n ). The n -dependent γ (n ) was obtained for a series of conditions systematically changed as (10 K, vacuum) → (300 K, vacuum) → (300 K, ambient pressure), which reveals that (1) at low-T, charged impurity (=A /√{n } ) and short-range defect (=B √{n } ) are the major scattering sources which constitute the total scattering γ =A /√{n }+B √{n } , (2) among various kinds of phonons populated at room-T , surface polar phonon of the SiO2 substrate is the dominantly scattering source, and (3) in air, the gas molecules adsorbed on graphene play a dual role in carrier scattering as charged impurity center and resonant scattering center. We present the absolute scattering strengths of those individual scattering sources, which provides the complete map of scattering mechanism of CVD graphene. This scattering map allows us to find out practical measures to suppress the individual scatterings, the mobility gains accompanied by them, and finally the ultimate attainable carrier mobility for CVD graphene.

  17. Mass production of CNTs using CVD multi-quartz tubes

    Energy Technology Data Exchange (ETDEWEB)

    Yousef, Samy; Mohamed, Alaa [Dept. of Production Engineering and Printing Technology, Akhbar Elyom Academy, Giza (Egypt)

    2016-11-15

    Carbon nanotubes (CNTs) have become the backbone of modern industries, including lightweight and heavy-duty industrial applications. Chemical vapor deposition (CVD) is considered as the most common method used to synthesize high yield CNTs. This work aims to develop the traditional CVD for the mass production of more economical CNTs, meeting the growing CNT demands among consumers by increasing the number of three particular reactors. All reactors housing is connected by small channels to provide the heat exchange possibility between the chambers, thereby decreasing synthesis time and reducing heat losses inside the ceramic body of the furnace. The novel design is simple and cheap with a lower reacting time and heat loss compared with the traditional CVD design. Methane, hydrogen, argon, and catalyzed iron nanoparticles were used as a carbon source and catalyst during the synthesis process. In addition, CNTs were produced using only a single quartz tube for comparison. The produced samples were examined using XRD, TEM, SEM, FTIR, and TGA. The results showed that the yield of CNTs increases by 287 % compared with those synthesized with a single quartz tube. Moreover, the total synthesis time of CNTs decreases by 37 % because of decreased heat leakage.

  18. Ultra-high Burst Strength of CVD Graphene Membranes

    Science.gov (United States)

    Wang, Luda; Boutilier, Michael; Kidambi, Piran; Karnik, Rohit; Microfluidics; Nanofluidics Research Lab Team

    2015-11-01

    Porous graphene membranes have significant potential in gas separation, water desalination and nanofiltration. Understanding the mechanical strength of porous graphene is crucial because membrane separations can involve high pressures. We studied the burst strength of CVD graphene membrane placed on porous support at applied pressures up to 100 bar by monitoring the gas flow rate across the membrane as a function of pressure. Increase of gas flow rate with pressure allowed for extraction of the burst fraction of graphene as it failed under increasing pressure. We also studied the effect of sub-nanometer pores on the ability of graphene to withstand pressure. The results showed that porous graphene membranes can withstand pressures comparable to or even higher than the >50 bar pressures encountered in water desalination, with non-porous CVD graphene exhibiting even higher mechanical strength. Our study shows that porous polycrystalline CVD graphene has ultra-high burst strength under applied pressure, suggesting the possibility for its use in high-pressure membrane separations. Principal Investigator

  19. Approach to diabetes management in patients with CVD.

    Science.gov (United States)

    Lathief, Sanam; Inzucchi, Silvio E

    2016-02-01

    Epidemiologic analyses have established a clear association between diabetes and macrovascular disease. Vascular dysfunction caused by metabolic abnormalities in patients with diabetes is associated with accelerated atherosclerosis and increased risk of myocardial infarction (MI), stroke, and peripheral arterial disease. Patients with diabetes are at two to four fold higher CV risk as compared to non-diabetic individuals, and CVD remains the leading cause of mortality in patients with this condition. One strategy to reduce CVD burden in patients with diabetes has been to focus on controlling the major metabolic abnormality in this condition, namely hyperglycemia. However, this has not been unequivocally demonstrated to reduced CV events, in contrast to controlling other CVD risk factors linked to hyperglycemia, such as blood pressure, dyslipidemia, and platelet dysfunction. However, In contradistinction, accrued data from a number of large, randomized clinical trials in both type 1 (T1DM) and type 2 diabetes (T2DM) over the past 3 decades have proven that more intensive glycemic control retards the onset and progression of microvascular disease. In this review, we will summarize the key glucose-lowering CV outcomes trials in diabetes, provide an overview of the different drugs and their impact on the CV system, and describe our approach to management of the frequently encountered patient with T2DM and coronary artery disease (CAD) and/or heart failure (HF).

  20. The Role of Government in Responding to Foreign CVD Investigations:Shenzhen’s Experiences

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>The paper probes into a series of meaningful and constructive work accomplished by Shenzhen government on foreign CVD investigations.Specifically, this paper analyzes the characteristics of CVD investigations for Shenzhen and the harmful impact of CVD investigation.It evaluates the major investigated subsidy programs in foreign CVDs against Chinese imports and discusses how to avoid CVD cases effectively and analyzes the principal measures taken by Shenzhen in dealing with CVD investigations concretely.The paper concludes that these works not only promoted the implementation of China’s WTO commitments,but also contributed to boost Shenzhen economic and social development and internationalization.

  1. Test of a prototype neutron spectrometer based on diamond detectors in a fast reactor

    CERN Document Server

    Osipenko, M; Ripani, M; Pillon, M; Ricco, G; Caiffi, B; Cardarelli, R; Verona-Rinati, G; Argiro, S

    2015-01-01

    A prototype of neutron spectrometer based on diamond detectors has been developed. This prototype consists of a $^6$Li neutron converter sandwiched between two CVD diamond crystals. The radiation hardness of the diamond crystals makes it suitable for applications in low power research reactors, while a low sensitivity to gamma rays and low leakage current of the detector permit to reach good energy resolution. A fast coincidence between two crystals is used to reject background. The detector was read out using two different electronic chains connected to it by a few meters of cable. The first chain was based on conventional charge-sensitive amplifiers, the other used a custom fast charge amplifier developed for this purpose. The prototype has been tested at various neutron sources and showed its practicability. In particular, the detector was calibrated in a TRIGA thermal reactor (LENA laboratory, University of Pavia) with neutron fluxes of $10^8$ n/cm$^2$s and at the 3 MeV D-D monochromatic neutron source na...

  2. CHEMICAL PRETREATMENTS OF THE SURFACE OF WC-15wt%Co WITH DIAMOND COATINGS

    Institute of Scientific and Technical Information of China (English)

    S. Liu; Z.M. Yu; D.Q. Yi; Y.X. Li

    2001-01-01

    Diamond films were deposited on the cemented carbide WC-15%Co substrates by a hot-filament chemical vapor deposition reactor. The substrate surfaces were chemically pretreated by the following two-step etching method: first using Murakami reagent for 1-3min, and second an HNO3:HCl=1:1 solution for 10-40min. It is indicated that the Co content of the substrate surfaces could be reduced from 15% to 0.81-6.04% within the etching depth of 5-10μm, the surface roughness of the substrates was increased up to Ra=1.0μm, and the substrates hardness was decreased from 89.0 HRA to 83.0HRA after the two-step etching. It is observed that the morphologies of the diamond films on the WC-15%Co substrates emerge in various shapes. The indentation testing shows that the good adhesion between diamond film and the substrate after HF CVD deposition could be obtained.

  3. Fabrication of monolithic microfluidic channels in diamond with ion beam lithography

    Science.gov (United States)

    Picollo, F.; Battiato, A.; Boarino, L.; Ditalia Tchernij, S.; Enrico, E.; Forneris, J.; Gilardino, A.; Jakšić, M.; Sardi, F.; Skukan, N.; Tengattini, A.; Olivero, P.; Re, A.; Vittone, E.

    2017-08-01

    In the present work, we report on the monolithic fabrication by means of ion beam lithography of hollow micro-channels within a diamond substrate, to be employed for microfluidic applications. The fabrication strategy takes advantage of ion beam induced damage to convert diamond into graphite, which is characterized by a higher reactivity to oxidative etching with respect to the chemically inert pristine structure. This phase transition occurs in sub-superficial layers thanks to the peculiar damage profile of MeV ions, which mostly damage the target material at their end of range. The structures were obtained by irradiating commercial CVD diamond samples with a micrometric collimated C+ ion beam at three different energies (4 MeV, 3.5 MeV and 3 MeV) at a total fluence of 2 × 1016 cm-2. The chosen multiple-energy implantation strategy allows to obtain a thick box-like highly damaged region ranging from 1.6 μm to 2.1 μm below the sample surface. High-temperature annealing was performed to both promote the graphitization of the ion-induced amorphous layer and to recover the pristine crystalline structure in the cap layer. Finally, the graphite was removed by ozone etching, obtaining monolithic microfluidic structures. These prototypal microfluidic devices were tested injecting aqueous solutions and the evidence of the passage of fluids through the channels was confirmed by confocal fluorescent microscopy.

  4. Rapid Growth of Nanostructured Diamond Film on Silicon and Ti–6Al–4V Alloy Substrates

    Directory of Open Access Journals (Sweden)

    Gopi K. Samudrala

    2014-01-01

    Full Text Available Nanostructured diamond (NSD films were grown on silicon and Ti–6Al–4V alloy substrates by microwave plasma chemical vapor deposition (MPCVD. NSD Growth rates of 5 µm/h on silicon, and 4 µm/h on Ti–6Al–4V were achieved. In a chemistry of H2/CH4/N2, varying ratios of CH4/H2 and N2/CH4 were employed in this research and their effect on the resulting diamond films were studied by X-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, and atomic force microscopy. As a result of modifying the stock cooling stage of CVD system, we were able to utilize plasma with high power densities in our NSD growth experiments, enabling us to achieve high growth rates. Substrate temperature and N2/CH4 ratio have been found to be key factors in determining the diamond film quality. NSD films grown as part of this study were shown to contain 85% to 90% sp3 bonded carbon.

  5. Ultrananocrystalline diamond contacts for electronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Sumant, Anirudha V.; Smedley, John; Muller, Erik

    2016-11-01

    A method of forming electrical contacts on a diamond substrate comprises producing a plasma ball using a microwave plasma source in the presence of a mixture of gases. The mixture of gases include a source of a p-type or an n-type dopant. The plasma ball is disposed at a first distance from the diamond substrate. The diamond substrate is maintained at a first temperature. The plasma ball is maintained at the first distance from the diamond substrate for a first time, and a UNCD film, which is doped with at least one of a p-type dopant and an n-type dopant, is disposed on the diamond substrate. The doped UNCD film is patterned to define UNCD electrical contacts on the diamond substrate.

  6. Copper-micrometer-sized diamond nanostructured composites

    Science.gov (United States)

    Nunes, D.; Livramento, V.; Shohoji, N.; Fernandes, H.; Silva, C.; Correia, J. B.; Carvalho, P. A.

    2011-12-01

    Reinforcement of a copper matrix with diamond enables tailoring the properties demanded for thermal management applications at high temperature, such as the ones required for heat sink materials in low activated nuclear fusion reactors. For an optimum compromise between thermal conductivity and mechanical properties, a novel approach based on multiscale diamond dispersions is proposed: a Cu-nanodiamond composite produced by milling is used as a nanostructured matrix for further dispersion of micrometer-sized diamondDiamond). A series of Cu-nanodiamond mixtures have been milled to establish a suitable nanodiamond fraction. A refined matrix with homogeneously dispersed nanoparticles was obtained with 4 at.% μDiamond for posterior mixture with microdiamond and subsequent consolidation. Preliminary consolidation by hot extrusion of a mixture of pure copper and μDiamond has been carried out to define optimal processing parameters. The materials produced were characterized by x-ray diffraction, scanning and transmission electron microscopy and microhardness measurements.

  7. Diamonds and the african lithosphere.

    Science.gov (United States)

    Boyd, F R; Gurney, J J

    1986-04-25

    Data and inferences drawn from studies of diamond inclusions, xenocrysts, and xenoliths in the kimberlites of southern Africa are combined to characterize the structure of that portion of the Kaapvaal craton that lies within the mantle. The craton has a root composed in large part of peridotites that are strongly depleted in basaltic components. The asthenosphere boundary shelves from depths of 170 to 190 kilometers beneath the craton to approximately 140 kilometers beneath the mobile belts bordering the craton on the south and west. The root formed earlier than 3 billion years ago, and at that time ambient temperatures in it were 900 degrees to 1200 degrees C; these temperatures are near those estimated from data for xenoliths erupted in the Late Cretaceous or from present-day heat-flow measurements. Many of the diamonds in southern Africa are believed to have crystallized in this root in Archean time and were xenocrysts in the kimberlites that brought them to the surface.

  8. Diamond turning machine controller implementation

    Energy Technology Data Exchange (ETDEWEB)

    Garrard, K.P.; Taylor, L.W.; Knight, B.F.; Fornaro, R.J.

    1988-12-01

    The standard controller for a Pnuemo ASG 2500 Diamond Turning Machine, an Allen Bradley 8200, has been replaced with a custom high-performance design. This controller consists of four major components. Axis position feedback information is provided by a Zygo Axiom 2/20 laser interferometer with 0.1 micro-inch resolution. Hardware interface logic couples the computers digital and analog I/O channels to the diamond turning machine`s analog motor controllers, the laser interferometer, and other machine status and control information. It also provides front panel switches for operator override of the computer controller and implement the emergency stop sequence. The remaining two components, the control computer hardware and software, are discussed in detail below.

  9. A Comparative Study of Three Different Chemical Vapor Deposition (CVD) Techniques of Carbon Nanotube Growth on Diamond Films

    Science.gov (United States)

    2013-01-01

    a,b , Paul N. Barnes c , Chakrapani V. Varanasi e , Jack Burke d , Bang -Hung Tsao d , and Sharmila M. Mukhopadhyay b a. Air Force Research...catalysts play a big role in the structure and properties of the resulting CNTs. The three different techniques compared here have two different approaches...catalysts at the interface suggests the silica nanolayer keeps them anchored and prevents them from migrating during CNT growth. Figure 5: Cross

  10. Development of a beam condition monitor for use in experiments at the CERN Large Hadron Collider using synthetic diamond

    CERN Document Server

    Fernández-Hernando, L; Ilgner, C; MacPherson, A; Oh, A; Pernegger, H; Pritchard, T; Stone, R; Worm, S

    2004-01-01

    The CERN Large Hadron Collider (LHC) will collide two counter rotating proton beams, each with a store energy about 350MJ; enough to melt 550kg of copper. If there is failure in an element of the accelerator, the resulting beam losses could cause damage not only to the machine but also to the experiments. A Beam Condition Monitor (BCM) is foreseen to monitor last increments of particle flux near the interaction point and if necessary, to generate an abort signal to the LHC accelerator control, to dump the beams. Due to its radiation hardness and minimal services requirements, synthetic CVD diamond is being considered as BCM sensor option. (12 refs).

  11. Conductive diamond electrodes for water purification

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Martínez-Huitle

    2007-12-01

    Full Text Available Nowadays, synthetic diamond has been studied for its application in wastewater treatment, electroanalysis, organic synthesis and sensor areas; however, its use in the water disinfection/purification is its most relevant application. The new electrochemistry applications of diamond electrodes open new perspectives for an easy, effective, and chemical free water treatment. This article highlights and summarizes the results of a selection of papers dealing with electrochemical disinfection using synthetic diamond films.

  12. Nanotwinned diamond with unprecedented hardness and stability.

    Science.gov (United States)

    Huang, Quan; Yu, Dongli; Xu, Bo; Hu, Wentao; Ma, Yanming; Wang, Yanbin; Zhao, Zhisheng; Wen, Bin; He, Julong; Liu, Zhongyuan; Tian, Yongjun

    2014-06-12

    Although diamond is the hardest material for cutting tools, poor thermal stability has limited its applications, especially at high temperatures. Simultaneous improvement of the hardness and thermal stability of diamond has long been desirable. According to the Hall-Petch effect, the hardness of diamond can be enhanced by nanostructuring (by means of nanograined and nanotwinned microstructures), as shown in previous studies. However, for well-sintered nanograined diamonds, the grain sizes are technically limited to 10-30 nm (ref. 3), with degraded thermal stability compared with that of natural diamond. Recent success in synthesizing nanotwinned cubic boron nitride (nt-cBN) with a twin thickness down to ∼3.8 nm makes it feasible to simultaneously achieve smaller nanosize, ultrahardness and superior thermal stability. At present, nanotwinned diamond (nt-diamond) has not been fabricated successfully through direct conversions of various carbon precursors (such as graphite, amorphous carbon, glassy carbon and C60). Here we report the direct synthesis of nt-diamond with an average twin thickness of ∼5 nm, using a precursor of onion carbon nanoparticles at high pressure and high temperature, and the observation of a new monoclinic crystalline form of diamond coexisting with nt-diamond. The pure synthetic bulk nt-diamond material shows unprecedented hardness and thermal stability, with Vickers hardness up to ∼200 GPa and an in-air oxidization temperature more than 200 °C higher than that of natural diamond. The creation of nanotwinned microstructures offers a general pathway for manufacturing new advanced carbon-based materials with exceptional thermal stability and mechanical properties.

  13. Diamond Light Source: status and perspectives

    OpenAIRE

    Materlik, Gerhard; Rayment, Trevor; Stuart, David I.

    2015-01-01

    Diamond Light Source, a third-generation synchrotron radiation (SR) facility in the UK, celebrated its 10th anniversary in 2012. A private limited company was set up in April 2002 to plan, construct and operate the new user-oriented SR facility, called in brief Diamond. It succeeded the Synchrotron Radiation Source in Daresbury, a second-generation synchrotron that opened in 1980 as the world's first dedicated X-ray-providing facility, closing finally in 2008, by which time Diamond's accelera...

  14. Diamond-silicon carbide composite and method

    Science.gov (United States)

    Zhao, Yusheng

    2011-06-14

    Uniformly dense, diamond-silicon carbide composites having high hardness, high fracture toughness, and high thermal stability are prepared by consolidating a powder mixture of diamond and amorphous silicon. A composite made at 5 GPa/1673K had a measured fracture toughness of 12 MPam.sup.1/2. By contrast, liquid infiltration of silicon into diamond powder at 5 GPa/1673K produces a composite with higher hardness but lower fracture toughness.

  15. Entanglement, holography and causal diamonds

    Science.gov (United States)

    de Boer, Jan; Haehl, Felix M.; Heller, Michal P.; Myers, Robert C.

    2016-08-01

    We argue that the degrees of freedom in a d-dimensional CFT can be reorganized in an insightful way by studying observables on the moduli space of causal diamonds (or equivalently, the space of pairs of timelike separated points). This 2 d-dimensional space naturally captures some of the fundamental nonlocality and causal structure inherent in the entanglement of CFT states. For any primary CFT operator, we construct an observable on this space, which is defined by smearing the associated one-point function over causal diamonds. Known examples of such quantities are the entanglement entropy of vacuum excitations and its higher spin generalizations. We show that in holographic CFTs, these observables are given by suitably defined integrals of dual bulk fields over the corresponding Ryu-Takayanagi minimal surfaces. Furthermore, we explain connections to the operator product expansion and the first law of entanglemententropy from this unifying point of view. We demonstrate that for small perturbations of the vacuum, our observables obey linear two-derivative equations of motion on the space of causal diamonds. In two dimensions, the latter is given by a product of two copies of a two-dimensional de Sitter space. For a class of universal states, we show that the entanglement entropy and its spin-three generalization obey nonlinear equations of motion with local interactions on this moduli space, which can be identified with Liouville and Toda equations, respectively. This suggests the possibility of extending the definition of our new observables beyond the linear level more generally and in such a way that they give rise to new dynamically interacting theories on the moduli space of causal diamonds. Various challenges one has to face in order to implement this idea are discussed.

  16. CZ: Multiple Inheritance Without Diamonds

    Science.gov (United States)

    2008-12-01

    be solved by allowing renaming (e.g., Eiffel [24]) or by linearizing the class hierarchy [33, 32]. However, there is still no satisfactory solution to...desirable semantics; it is supported in languages such as Scala, Eiffel , and C++ (the last through virtual inheritance) [28, 24, 18]. Next, diamond...Languages that attempt to solve the object initialization problem include Eiffel [24], C++ [18], Scala [28] and Smalltalk with stateful traits [8

  17. Nonclassical radiation from diamond nanocrystals

    CERN Document Server

    Beveratos, A; Gacoin, T; Poizat, J P; Grangier, P; Beveratos, Alexios; Brouri, Rosa; Gacoin, Thierry; Poizat, Jean-Philippe; Grangier, Philippe

    2001-01-01

    The quantum properties of the fluorescence light emitted by diamond nanocrystals containing a single nitrogen-vacancy (NV) colored center is investigated. We have observed photon antibunching with very low background light. This system is therefore a very good candidate for the production of single photon on demand. In addition, we have measured larger NV center lifetime in nanocrystals than in the bulk, in good agreement with a simple quantum electrodynamical model.

  18. Thermal Conductivity of Diamond Composites

    Directory of Open Access Journals (Sweden)

    Fedor M. Shakhov

    2009-12-01

    Full Text Available A major problem challenging specialists in present-day materials sciences is the development of compact, cheap to fabricate heat sinks for electronic devices, primarily for computer processors, semiconductor lasers, high-power microchips, and electronics components. The materials currently used for heat sinks of such devices are aluminum and copper, with thermal conductivities of about 250 W/(m·K and 400 W/(m·K, respectively. Significantly, the thermal expansion coefficient of metals differs markedly from those of the materials employed in semiconductor electronics (mostly silicon; one should add here the low electrical resistivity metals possess. By contrast, natural single-crystal diamond is known to feature the highest thermal conductivity of all the bulk materials studied thus far, as high as 2,200 W/(m·K. Needless to say, it cannot be applied in heat removal technology because of high cost. Recently, SiC- and AlN-based ceramics have started enjoying wide use as heat sink materials; the thermal conductivity of such composites, however, is inferior to that of metals by nearly a factor two. This prompts a challenging scientific problem to develop diamond-based composites with thermal characteristics superior to those of aluminum and copper, adjustable thermal expansion coefficient, low electrical conductivity and a moderate cost, below that of the natural single-crystal diamond. The present review addresses this problem and appraises the results reached by now in studying the possibility of developing composites in diamond-containing systems with a view of obtaining materials with a high thermal conductivity.

  19. Diamond turning of thermoplastic polymers

    Energy Technology Data Exchange (ETDEWEB)

    Smith, E.; Scattergood, R.O.

    1988-12-01

    Single point diamond turning studies were made using a series of thermoplastic polymers with different glass transition temperatures. Variations in surface morphology and surface roughness were observed as a function of cutting speed. Lower glass transition temperatures facilitate smoother surface cuts and better surface finish. This can be attributed to the frictional heating that occurs during machining. Because of the very low glass transition temperatures in polymeric compared to inorganic glasses, the precision machining response can be very speed sensitive.

  20. ATLAS diamond Beam Condition Monitor

    CERN Document Server

    Gorišek, A; Dolenc, I; Frais-Kölbl, H; Griesmayer, E; Kagan, H; Korpar, S; Kramberger, G; Mandic, I; Meyer, M; Mikuz, M; Pernegger, H; Smith, S; Trischuk, W; Weilhammer, P; Zavrtanik, M

    2007-01-01

    The ATLAS experiment has chosen to use diamond for its Beam Condition Monitor (BCM) given its radiation hardness, low capacitance and short charge collection time. In addition, due to low leakage current diamonds do not require cooling. The ATLAS Beam Condition Monitoring system is based on single beam bunch crossing measurements rather than integrating the accumulated particle flux. Its fast electronics will allow separation of LHC collisions from background events such as beam gas interactions or beam accidents. There will be two stations placed symmetrically about the interaction point along the beam axis at . Timing of signals from the two stations will provide almost ideal separation of beam–beam interactions and background events. The ATLAS BCM module consists of diamond pad detectors of area and thickness coupled to a two-stage RF current amplifier. The production of the final detector modules is almost done. A S/N ratio of 10:1 has been achieved with minimum ionizing particles (MIPs) in the test bea...

  1. Generation of microdischarges in diamond substrates

    Science.gov (United States)

    Mitea, S.; Zeleznik, M.; Bowden, M. D.; May, P. W.; Fox, N. A.; Hart, J. N.; Fowler, C.; Stevens, R.; StJ Braithwaite, N.

    2012-04-01

    We report the generation of microdischarges in devices composed of microcrystalline diamond. Discharges were generated in device structures with microhollow cathode discharge geometries. One structure consisted of an insulating diamond wafer coated with boron-doped diamond layers on both sides. A second structure consisted of an insulating diamond wafer coated with metal layers on both sides. In each case, a single sub-millimetre hole was machined through the conductor-insulator-conductor structure. The discharges were generated in a helium atmosphere. Breakdown voltages were around 500 V and discharge currents in the range 0.1-2.5 mA were maintained by a sustaining dc voltage of 300 V.

  2. All diamond self-aligned thin film transistor

    Science.gov (United States)

    Gerbi, Jennifer [Champaign, IL

    2008-07-01

    A substantially all diamond transistor with an electrically insulating substrate, an electrically conductive diamond layer on the substrate, and a source and a drain contact on the electrically conductive diamond layer. An electrically insulating diamond layer is in contact with the electrically conductive diamond layer, and a gate contact is on the electrically insulating diamond layer. The diamond layers may be homoepitaxial, polycrystalline, nanocrystalline or ultrananocrystalline in various combinations.A method of making a substantially all diamond self-aligned gate transistor is disclosed in which seeding and patterning can be avoided or minimized, if desired.

  3. Boron doped diamond thin films on large area Ti6Al4V substrates for electrochemical application

    Directory of Open Access Journals (Sweden)

    Alessandra V. Diniz

    2003-01-01

    Full Text Available Boron doped diamond thin films were grown on titanium alloy substrates (Ti6Al4V with 36 × 35 × 1.3 mm at 873-933 K at 6.5 × 10³ Pa during 8 h by hot filament CVD assisted technique. The boron source was obtained from a H2 line forced to pass through a bubbler containing B2O3 dissolved in methanol (BC = 6000 ppm. The films were grown on both sides of perforated and non-perforated substrates. Emphasis for diamond growing on perforated substrates have been done in order to increase the active surface area and hereafter to promote an easier electrolyte flow for wastewater treatment. The electrode performance was determined by cyclic voltammetry measurements in KCl, KNO3, Na2SO4, HCl, HNO3 and H2SO4 solutions and the reversibility behavior of the Fe(CN6(3-/4- at the Ti6Al4V/Diamond electrode were studied. Also, Scaning Electron Microcopy and Raman Scattering Spectroscopy were used for morphology and diamond quality evaluation, respectively.

  4. Nanostructured TaxC interlayer synthesized via double glow plasma surface alloying process for diamond deposition on cemented carbide

    Science.gov (United States)

    Rong, Wolong; Hei, Hongjun; Zhong, Qiang; Shen, Yanyan; Liu, Xiaoping; Wang, Xin; Zhou, Bing; He, Zhiyong; Yu, Shengwang

    2015-12-01

    The aim in this work was to improve the adhesion of diamond coating with pre-deposition of a TaxC interlayer on cemented carbide (WC-Co) substrate by double glow plasma surface alloying technique. The following deposition of diamond coating on the interlayer was performed in a microwave plasma chemical vapor deposition (MPCVD) reactor. TaxC interlayer with an inner diffusion layer and an outer deposition layer was composed of Ta2C and TaC nanocrystalline, and it exhibited a special compact surface morphology formed of flower-shaped pits. As the gradual element distributions existed in the diffusion layer, the interlayer displayed a superior adherence to the substrate with significantly enhanced surface microhardness to the original substrate. After CVD process, the preferred orientation of TaC changed from (2 2 2) to (2 0 0) plane, and a uniform and tense diamond coating with adhesion referred to class HF 2 at least (Verein Deutscher Ingenieure 3198 norm) was obtained on the interlayered substrate. It indicated that the diffusion of Co was effectively inhibited by the formation of TaxC diffusion-deposition interlayer. The TaxC interlayer is most likely to improve the performance of diamond coatings used in cutting tools.

  5. THE CONCENTRATION OF DIAMONDS INFLUENCES THE WEAR OF BEADS IN SAWING DIMENSION STONE WITH DIAMOND WIRE SAWING PLANT

    Directory of Open Access Journals (Sweden)

    Siniša Dunda

    1993-12-01

    Full Text Available The influence of diamond concentration to the wear or diamond layer and to the life time of the diamond wire has experimentally tested. The changes of the diamond concentration were achieved by changing the beads' pace per m' of diamond wire. Upon the obtained results of the experiment, the optimal concentration of diamonds has been established, also considering the least cost, per square meter of sawing (the paper is published in Croatian.

  6. Evaluation of a bivalent (CVD 103-HgR/CVD 111) live oral cholera vaccine in adult volunteers from the United States and Peru.

    Science.gov (United States)

    Taylor, D N; Tacket, C O; Losonsky, G; Castro, O; Gutierrez, J; Meza, R; Nataro, J P; Kaper, J B; Wasserman, S S; Edelman, R; Levine, M M; Cryz, S J

    1997-09-01

    To provide optimum protection against classical and El Tor biotypes of Vibrio cholerae O1, a single-dose, oral cholera vaccine was developed by combining two live, attenuated vaccine strains, CVD 103-HgR (classical, Inaba) and CVD 111 (El Tor, Ogawa). The vaccines were formulated in a double-chamber sachet; one chamber contained lyophilized bacteria, and the other contained buffer. In the first study, 23 U.S. adult volunteers received CVD 103-HgR at 10(8) CFU plus CVD 111 at 10(8), 10(7), or 10(6) CFU, CVD 111 alone at 10(7) CFU, or placebo. In the second study, 275 Peruvian adults were randomized to receive CVD 103-HgR at 10(9) CFU plus CVD 111 at 10(9) or 10(8) CFU, CVD 111 alone at 10(9) CFU, CVD 103-HgR alone at 10(9) CFU, or placebo. Three of 15 U.S. volunteers who received CVD 111 at 10(7) or 10(8) CFU developed mild diarrhea, compared to none of 4 who received CVD 111 at 10(6) CFU and 1 of 4 who received placebo. Twelve (63%) of 19 vaccine recipients shed the El Tor vaccine strain. All but one volunteer developed significant Ogawa and Inaba vibriocidal antibody titers. Volunteers who received CVD 111 at 10(7) CFU had geometric mean Ogawa titers four to five times higher than those of volunteers who received the lower dose. In the second study, all dosage regimens were well tolerated in Peruvians. About 20% of volunteers who received CVD 111 at the high dose excreted the El Tor organism, compared to 7% in the low-dose group. CVD 111 was detected in the stools of two placebo recipients, neither of whom had symptoms or seroconverted. In all vaccine groups, 69 to 76% developed fourfold rises in Inaba vibriocidal antibodies. Among those who received the bivalent vaccine, 53 to 75% also developed significant rises in Ogawa vibriocidal antibodies. We conclude that it is feasible to produce a single-dose, oral bivalent vaccine that is safe and immunogenic against both biotypes (El Tor and classical) and both serotypes (Inaba and Ogawa) of cholera for populations in

  7. The mechanical and strength properties of diamond.

    Science.gov (United States)

    Field, J E

    2012-12-01

    Diamond is an exciting material with many outstanding properties; see, for example Field J E (ed) 1979 The Properties of Diamond (London: Academic) and Field J E (ed) 1992 The Properties of Natural and Synthetic Diamond (London: Academic). It is pre-eminent as a gemstone, an industrial tool and as a material for solid state research. Since natural diamonds grew deep below the Earth's surface before their ejection to mineable levels, they also contain valuable information for geologists. The key to many of diamond's properties is the rigidity of its structure which explains, for example, its exceptional hardness and its high thermal conductivity. Since 1953, it has been possible to grow synthetic diamond. Before then, it was effectively only possible to have natural diamond, with a small number of these found in the vicinity of meteorite impacts. Techniques are now available to grow gem quality synthetic diamonds greater than 1 carat (0.2 g) using high temperatures and pressures (HTHP) similar to those found in nature. However, the costs are high, and the largest commercially available industrial diamonds are about 0.01 carat in weight or about 1 mm in linear dimension. The bulk of synthetic diamonds used industrially are 600 µm or less. Over 75% of diamond used for industrial purposes today is synthetic material. In recent years, there have been two significant developments. The first is the production of composites based on diamond; these materials have a significantly greater toughness than diamond while still maintaining very high hardness and reasonable thermal conductivity. The second is the production at low pressures by metastable growth using chemical vapour deposition techniques. Deposition onto non-diamond substrates was first demonstrated by Spitsyn et al 1981 J. Cryst. Growth 52 219-26 and confirmed by Matsumoto et al 1982 Japan J. Appl. Phys. 21 L183-5. These developments have added further to the versatility of diamond. Two other groups of

  8. The provenance of Borneo's enigmatic alluvial diamonds

    Science.gov (United States)

    White, Lloyd; Graham, Ian; Tanner, Dominique; Hall, Robert; Armstrong, Richard; Yaxley, Greg; Barron, Larry; Spencer, Lee; van Leeuwen, Theo

    2016-04-01

    Gem-quality diamonds occur in several alluvial deposits across central and southern Borneo. Borneo has been a known source of diamonds for centuries, but the location of their primary igneous source remains enigmatic. Numerous geological models have been proposed to explain the distribution of Borneo's diamonds. To assess these models, we used a variety of techniques to examine heavy minerals from Kalimantan's Cempaka paleoalluvial diamond deposit. This involved collecting U-Pb isotopic data, fission track and trace element geochemistry of zircon as well as major element geochemical data of spinels and morphological descriptions of zircon and diamond. Our results indicate that the Cempaka diamonds were likely derived from at least two sources, one which was relatively local and/or involved little reworking, and the other more distal recording several periods of reworking. The distal diamond source is interpreted to be diamond-bearing pipes that intruded the basement of a block that: (1) rifted from northwest Australia (East Java or SW Borneo) and the diamonds were recycled into its sedimentary cover, or: (2) were emplaced elsewhere (e.g. NW Australia) and transported to a block (e.g. East Java or SW Borneo). Both of these scenarios require the diamonds to be transported with the block when it rifted from NW Australia in the Late Jurassic. The 'local' diamonds could be associated with ophiolitic rocks that are exposed in the nearby Meratus Mountains, or could be diamondiferous diatremes associated with eroded Miocene high-K alkaline intrusions north of the Barito Basin. If this were the case, these intrusions would indicate that the lithosphere beneath SW Borneo is thick (~150 km or greater).

  9. Electrochemical diamond sensors for TNT detection in water

    Energy Technology Data Exchange (ETDEWEB)

    Sanoit, J. de [CEA-LIST-DETECS, Laboratoire Capteur Diamant, CEA-Saclay, Gif-sur Yvette, F-91191 (France)], E-mail: jacques.desanoit@cea.fr; Vanhove, Emilie [CEA-LIST-DETECS, Laboratoire Capteur Diamant, CEA-Saclay, Gif-sur Yvette, F-91191 (France); Mailley, Pascal [INAC, SPrAM, CREAB (CEA-Grenoble), F-38021 (France); Bergonzo, Philippe [CEA-LIST-DETECS, Laboratoire Capteur Diamant, CEA-Saclay, Gif-sur Yvette, F-91191 (France)

    2009-10-01

    An electrochemically stabilized boron doped diamond electrode prepared by chemical vapour deposition (CVD) is used for electrochemical TNT sensing in aqueous solutions. Square wave voltammograms (SWVs) exhibit three highly resolved peaks at -0.47, -0.62 and -0.76 V vs. Ag-AgCl reference electrode, respectively. The current vs. TNT concentration plot shows a linear relationship with a same slope for the two first TNT peaks at {mu}g L{sup -1} and mg L{sup -1} concentration ranges. Detection and quantification limits of 10 and 25 {mu}g L{sup -1}, respectively, were obtained without any preconcentration step. Relative standard deviation (RSD) of less than 1% measured over 10 runs has been found for the -0.47 V peak current showing the very high stability of the electrode without any significant fouling effect. An interference study with nitro aromatic compounds of the same family (nitro toluene and dinitrotoluene) has shown that the -0.47 V reduction peak enables TNT discrimination. Measurement of TNT in a natural medium (sea water without any purification step except filtering) has been also investigated.

  10. Laser diagnostics of chemical vapour deposition of diamond films

    CERN Document Server

    Wills, J B

    2002-01-01

    Cavity ring down spectroscopy (CRDS) has been used to make diagnostic measurements of chemically activated CH sub 4 / H sub 2 gas mixtures during the chemical vapour deposition (CVD) of thin diamond films. Absolute absorbances, concentrations and temperatures are presented for CH sub 3 , NH and C sub 2 H sub 2 in a hot filament (HF) activated gas mixture and CH, C sub 2 and C sub 2 H sub 2 in a DC arc plasma jet activated mixture. Measurements of the radical species were made using a pulsed dye laser system to generate tuneable visible and UV wavelengths. These species have greatest concentration in the hottest, activated regions of the reactors. Spatial profiling of the number densities of CH sub 3 and NH radicals have been used as stringent tests of predictions of radical absorbance and number densities made by 3-D numerical simulations, with near quantitative agreement. O sub 2 has been shown to reside in the activated region of the Bristol DC arc jet at concentrations (approx 10 sup 1 sup 3 molecules / cm...

  11. Oats and CVD risk markers: a systematic literature review.

    Science.gov (United States)

    Thies, Frank; Masson, Lindsey F; Boffetta, Paolo; Kris-Etherton, Penny

    2014-10-01

    High consumption of whole-grain food such as oats is associated with a reduced risk of CVD and type 2 diabetes. The present study aimed to systematically review the literature describing long-term intervention studies that investigated the effects of oats or oat bran on CVD risk factors. The literature search was conducted using Embase, Medline and the Cochrane library, which identified 654 potential articles. Seventy-six articles describing sixty-nine studies met the inclusion criteria. Most studies lacked statistical power to detect a significant effect of oats on any of the risk factors considered: 59 % of studies had less than thirty subjects in the oat intervention group. Out of sixty-four studies that assessed systemic lipid markers, thirty-seven (58 %) and thirty-four (49 %) showed a significant reduction in total cholesterol (2-19 % reduction) and LDL-cholesterol (4-23 % reduction) respectively, mostly in hypercholesterolaemic subjects. Few studies (three and five, respectively) described significant effects on HDL-cholesterol and TAG concentrations. Only three out of twenty-five studies found a reduction in blood pressure after oat consumption. None of the few studies that measured markers of insulin sensitivity and inflammation found any effect after long-term oat consumption. Long-term dietary intake of oats or oat bran has a beneficial effect on blood cholesterol. However, there is no evidence that it favourably modulates insulin sensitivity. It is still unclear whether increased oat consumption significantly affects other risk markers for CVD risk, and comprehensive, adequately powered and controlled intervention trials are required to address this question.

  12. Epigenetic modifications and human pathologies: cancer and CVD.

    Science.gov (United States)

    Duthie, Susan J

    2011-02-01

    Epigenetic changes are inherited alterations in DNA that affect gene expression and function without altering the DNA sequence. DNA methylation is one epigenetic process implicated in human disease that is influenced by diet. DNA methylation involves addition of a 1-C moiety to cytosine groups in DNA. Methylated genes are not transcribed or are transcribed at a reduced rate. Global under-methylation (hypomethylation) and site-specific over-methylation (hypermethylation) are common features of human tumours. DNA hypomethylation, leading to increased expression of specific proto-oncogenes (e.g. genes involved in proliferation or metastasis) can increase the risk of cancer as can hypermethylation and reduced expression of tumour suppressor (TS) genes (e.g. DNA repair genes). DNA methyltransferases (DNMT), together with the methyl donor S-adenosylmethionine (SAM), facilitate DNA methylation. Abnormal DNA methylation is implicated not only in the development of human cancer but also in CVD. Polyphenols, a group of phytochemicals consumed in significant amounts in the human diet, effect risk of cancer. Flavonoids from tea, soft fruits and soya are potent inhibitors of DNMT in vitro, capable of reversing hypermethylation and reactivating TS genes. Folates, a group of water-soluble B vitamins found in high concentration in green leafy vegetables, regulate DNA methylation through their ability to generate SAM. People who habitually consume the lowest level of folate or with the lowest blood folate concentrations have a significantly increased risk of developing several cancers and CVD. This review describes how flavonoids and folates in the human diet alter DNA methylation and may modify the risk of human colon cancer and CVD.

  13. Homoepitaxial Boron Doped Diamond Anvil as Heating Element in a Diamond Anvil Cell

    Science.gov (United States)

    Montgomery, Jeffrey; Samudrala, Gopi; Vohra, Yogesh

    2012-02-01

    Recent advances in designer-diamond technology have allowed for the use of electrically and thermally conducting homoepitaxially-grown layers of boron-doped diamond (grown at 1200 C with a 2% mixture of CH4 in H, resulting in extremely high doping levels ˜ 10^20/cm^3) to be used as heating elements in a diamond anvil cell (DAC). These diamonds allow for precise control of the temperature inside of the diamond anvil itself, particularly when coupled with a cryostat. Furthermore, the unmatched thermally conducting nature of diamond ensures that no significant spatial gradient in temperature occurs across the culet area. Since a thermocouple can easily be attached anywhere on the diamond surface, we can also measure diamond temperatures directly. With two such heaters, one can raise sample temperatures uniformly, or with any desired gradient along the pressure axis while preserving optical access. In our initial experiments with these diamond anvils we report on the measurement of the thermal conductivity of copper-beryllium using a single diamond heater and two thermocouples. We augment these measurements with measurements of sample pressure via ruby fluorescence and electrical resistance of the sample and diamond heater.

  14. Improved CVD Techniques for Depositing Passivation Layers of ICs

    Science.gov (United States)

    1975-10-01

    went into compressive stress of 1.3 x 10 dynes/cm2. Results NX • thus show that room-temperature stress in CVD films can be reduced to nearly 35 -4 0...fluorescence working curves. X-ray fluorescence radiation measurements were carried out using a Siemens Crystalloflex 4 x-ray generator with a chromium target x...ray tube (2000 W) and a Siemens Vacuum X-Ray Spectrometer Model VRS. Sample area of measurement was usually 0.50 cm2 . 2= Experimental results will be

  15. CVD growth and processing of graphene for electronic applications

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Shishir; Rezvani, Ehsan; Nolan, Hugo; Duesberg, Georg S. [School of Chemistry, Trinity College Dublin, Dublin 2 (Ireland); Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2 (Ireland); McEvoy, Niall; Kim, Hye-Young; Lee, Kangho; Peltekis, Nikos; Weidlich, Anne; Daly, Ronan [Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2 (Ireland)

    2011-11-15

    The remarkable properties of graphene have potential for numerous applications; however, their exploitation depends on its reliable production. The chemical vapour deposition (CVD) growth of graphene on metal surfaces has become one of the most promising strategies for the production of high quality graphene in a scaleable manner. Here, we discuss graphene growth on nickel (Ni) and copper (Cu) directly from both gaseous hydrocarbons and solid carbon precursors. Further, we discuss in detail the transfer of graphene films to insulating substrates, by direct and polymer supported transfer methods. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Facility for continuous CVD coating of ceramic fibers

    Science.gov (United States)

    Moore, Arthur W.

    1992-01-01

    An inductively heated CVD furnace of pilot-plant scale, whose hot zone is 150 mm in diameter x 300 mm in length, has been adapted for continuous coating of ceramic yarns. Coatings at very low pressures are possible in this facility due to the fact that the entire apparatus, including yarn feeding and collecting equipment, is under vacuum. SiC yarn has been coated with 0.1-0.2 microns of BN at yarn speeds of 60 cm/min; a 500-m spool; was coated in about 14 hrs. Coating capacity was tripled by adding pulleys to allow three yarn passes through the furnace.

  17. CVD of pure copper films from amidinate precursor

    OpenAIRE

    2009-01-01

    Copper(I) amidinate [Cu(i-Pr-Me-AMD)]2 was investigated to produce copper films in conventional low pressure chemical vapor deposition (CVD) using hydrogen as reducing gas-reagent. Copper films were deposited on steel, silicon, and SiO2/Si substrates in the temperature range 200–350°C at a total pressure of 1333 Pa. The growth rate on steel follows the surface reaction between atomic hydrogen and the entire precursor molecule up to 240°C. A significant increase of the growth rate at tempera...

  18. Development of CVD Mullite Coatings for SiC Fibers

    Energy Technology Data Exchange (ETDEWEB)

    Sarin, V.K.; Varadarajan, S.

    2000-03-15

    A process for depositing CVD mullite coatings on SiC fibers for enhanced oxidation and corrosion, and/or act as an interfacial protective barrier has been developed. Process optimization via systematic investigation of system parameters yielded uniform crystalline mullite coatings on SiC fibers. Structural characterization has allowed for tailoring of coating structure and therefore properties. High temperature oxidation/corrosion testing of the optimized coatings has shown that the coatings remain adherent and protective for extended periods. However, preliminary tests of coated fibers showed considerable degradation in tensile strength.

  19. Chromized Layers Produced on Steel Surface by Means of CVD

    Institute of Scientific and Technical Information of China (English)

    KASPRZYCKA Ewa; BOGDA(N)SKI Bogdan; JEZIORSKI Leopold; JASI(N)SKI J(o)zef; TORBUS Roman

    2004-01-01

    Chemical vapour deposition of chromium on the surface of carbon steel has been investigated using a novel CVD method that combines the low cost of pack cementation method with advantages of vacuum technique. The processes have been performed in chromium chlorides atmosphere at a low pressure range from 1 to 800 hPa, the treatment temperature 800 to 950℃. Studies of the layers thickness, the phase composition, Cr, C and Fe depth profiles in diffusion zone have been conducted. The effect of the vacuum level during the process and the process parameters such as time and temperature on layer diffusion growth on the carbon steel surface has been investigated.

  20. Trace elements in Gem-Quality Diamonds - Origin and evolution of diamond-forming fluid inclusions

    Science.gov (United States)

    Pearson, Graham; Krebs, Mandy; Stachel, Thomas; Woodland, Sarah; Chinn, Ingrid; Kong, Julie

    2017-04-01

    In the same way that melt inclusions in phenocrysts have expanded our idea of melt formation and evolution in basalts, studying fluids trapped in diamonds is providing important new constraints on the nature of diamond-forming fluids. Fibrous and cloudy diamonds trap a high but variable density of fluid inclusions and so have been extensively studied using major and trace element compositions. In contrast, constraining the nature of the diamond-forming fluid for high purity gem-quality diamonds has been restricted by the rarity of available high quality trace element data. This is due to the extremely low concentrations of impurities that gem diamonds contain - often in the ppt range. The recent discovery of fluids in gem diamonds showing similar major element chemistry to fluid-rich diamonds suggest that many diamonds may share a common spectrum of parental fluids. Here we test this idea further. Recent advances in analytical techniques, in particular the development of the "off-line" laser ablation pre-concentration approach, have allowed fully quantitative trace element data to be recovered from "fluid-poor", high quality gem diamonds. We present trace element data for gem diamonds from a variety of locations from Canada, S. Africa and Russia, containing either silicate or sulphide inclusions to examine possible paragenetic or genetic differences between fluids. REE abundance in the "gem" diamonds vary from 0.1 to 0.0001 x chondrite. To a first order, we observe the same spectrum of trace element compositions in the gem diamonds as that seen in fluid-rich "fibrous" diamonds, supporting a common origin for the fluids. REE patterns range from extremely flat (Ce/Yb)n 2.5 to 5 (commonly in sulphide-bearing diamonds) to >70, the latter having significantly greater inter-element HFSE/LILE fractionation. In general, the fluids from the sulphide-bearing diamonds are less REE-enriched than the silicate-bearing diamonds, but the ranges overlap significantly. The very

  1. The Returns on Investment Grade Diamonds

    NARCIS (Netherlands)

    Renneboog, L.D.R.

    2013-01-01

    Abstract: This paper examines the risk-return characteristics of investment grade gems (white diamonds, colored diamonds and other types of gems including sapphires, rubies, and emeralds). The transactions are coming from gem auctions and span the period 1999-2012. Over our time frame, the annual no

  2. Nature and genesis of Kalimantan diamonds

    Science.gov (United States)

    Smith, Chris B.; Bulanova, Galina P.; Kohn, Simon C.; Milledge, H. Judith; Hall, Anne E.; Griffin, Brendan J.; Pearson, D. Graham

    2009-11-01

    The origin of alluvial diamonds from the four main diamond mining districts in Kalimantan was studied through characterisation of their properties, and determination of PT and age of formation of representative collections of diamonds from four localities of the island. The diamonds are mostly colourless, yellow or pale brown, shiny surfaced, dodecahedroids, octahedron/dodecahedroids, and more rarely cube combination forms. They are intensively resorbed. They have surface radiation damage and show abrasion features indicative of fluvial transportation and crustal recycling. The diamonds were polished down to expose internal structures and mineral inclusions. The majority of the diamonds are internally homogeneous or have simple octahedral zonation and show plastic deformation. Analysis by Fourier transform infra red spectroscopy of their N content and aggregation characteristics shows that many diamonds are well-aggregated type IaB implying a long-term, mantle residence time and/or high temperatures of formation. Identified inclusion parageneses are 68% peridotitic and 32% eclogitic. The peridotitic inclusions are represented by olivine, chromite, garnet, orthopyroxene and pentlandite. Olivines (Fo 92-93) belong to the dunite-harzburgite paragenesis, with one at Fo 90 identified as lherzolitic. Chromite inclusions with 65-66 wt.% Cr 2O 3 and 4.2 GPa) are consistent with a paleo-heat flow of 38 to 40 mW/m 2 and derivation from 120 to 160 km depth, i.e. subcontinental mantle lithosphere conditions similar to diamonds from African and Yakutian cratonic situations.

  3. The Returns on Investment Grade Diamonds

    NARCIS (Netherlands)

    Renneboog, L.D.R.

    2013-01-01

    Abstract: This paper examines the risk-return characteristics of investment grade gems (white diamonds, colored diamonds and other types of gems including sapphires, rubies, and emeralds). The transactions are coming from gem auctions and span the period 1999-2012. Over our time frame, the annual

  4. Anisotropic mechanical amorphization drives wear in diamond.

    Science.gov (United States)

    Pastewka, Lars; Moser, Stefan; Gumbsch, Peter; Moseler, Michael

    2011-01-01

    Diamond is the hardest material on Earth. Nevertheless, polishing diamond is possible with a process that has remained unaltered for centuries and is still used for jewellery and coatings: the diamond is pressed against a rotating disc with embedded diamond grit. When polishing polycrystalline diamond, surface topographies become non-uniform because wear rates depend on crystal orientations. This anisotropy is not fully understood and impedes diamond's widespread use in applications that require planar polycrystalline films, ranging from cutting tools to confinement fusion. Here, we use molecular dynamics to show that polished diamond undergoes an sp(3)-sp(2) order-disorder transition resulting in an amorphous adlayer with a growth rate that strongly depends on surface orientation and sliding direction, in excellent correlation with experimental wear rates. This anisotropy originates in mechanically steered dissociation of individual crystal bonds. Similarly to other planarization processes, the diamond surface is chemically activated by mechanical means. Final removal of the amorphous interlayer proceeds either mechanically or through etching by ambient oxygen.

  5. Bending diamonds by femtosecond laser ablation

    DEFF Research Database (Denmark)

    Balling, Peter; Esberg, Jakob; Kirsebom, Kim;

    2009-01-01

    We present a new method based on femtosecond laser ablation for the fabrication of statically bent diamond crystals. Using this method, curvature radii of 1 m can easily be achieved, and the curvature obtained is very uniform. Since diamond is extremely tolerant to high radiation doses, partly due...

  6. He-3 in diamonds - The cosmogenic component

    Science.gov (United States)

    Lal, D.; Craig, H.; Wacker, J. F.; Poreda, R.

    1989-02-01

    Results are presented of measurements of He-3 and He-4 concentrations in diamonds received directly from mines, as well as in industrual samples. None of the diamonds recovered from underground mining was found to have a He-3/He-4 ratio, R, exceeding three times the atmospheric He-3/He-4 ratio R(A), while one of the industrial diamonds was found to have an R value of 142 R(A). It is concluded that the hypothesis of Ozima et al. (1983) of high primordial He-3/He-4 ratios in diamonds exceeding MORB ratios is not required. The present findings on the He-3/He-4 ratios are explained as the result of cosmogenic and nucleogenic production of He-3 within the diamonds.

  7. Fiber-Coupled Diamond Quantum Nanophotonic Interface

    Science.gov (United States)

    Burek, Michael J.; Meuwly, Charles; Evans, Ruffin E.; Bhaskar, Mihir K.; Sipahigil, Alp; Meesala, Srujan; Machielse, Bartholomeus; Sukachev, Denis D.; Nguyen, Christian T.; Pacheco, Jose L.; Bielejec, Edward; Lukin, Mikhail D.; Lončar, Marko

    2017-08-01

    Color centers in diamond provide a promising platform for quantum optics in the solid state, with coherent optical transitions and long-lived electron and nuclear spins. Building upon recent demonstrations of nanophotonic waveguides and optical cavities in single-crystal diamond, we now demonstrate on-chip diamond nanophotonics with a high-efficiency fiber-optical interface achieving >90 % power coupling at visible wavelengths. We use this approach to demonstrate a bright source of narrow-band single photons based on a silicon-vacancy color center embedded within a waveguide-coupled diamond photonic crystal cavity. Our fiber-coupled diamond quantum nanophotonic interface results in a high flux (approximately 38 kHz) of coherent single photons (near Fourier limited at quantum networks that interface multiple emitters, both on chip and separated by long distances.

  8. Review Article: Quantum Nanophotonics in Diamond

    CERN Document Server

    Schröder, Tim; Zheng, Jiabao; Trusheim, Matthew E; Walsh, Michael; Chen, Edward H; Li, Luozhou; Bayn, Igal; Englund, Dirk

    2016-01-01

    The past decade has seen great advances in developing color centers in diamond for sensing, quantum information processing, and tests of quantum foundations. Increasingly, the success of these applications as well as fundamental investigations of light-matter interaction depend on improved control of optical interactions with color centers -- from better fluorescence collection to efficient and precise coupling with confined single optical modes. Wide ranging research efforts have been undertaken to address these demands through advanced nanofabrication of diamond. This review will cover recent advances in diamond nano- and microphotonic structures for efficient light collection, color center to nanocavity coupling, hybrid integration of diamond devices with other material systems, and the wide range of fabrication methods that have enabled these complex photonic diamond systems.

  9. Diamond electrophoretic microchips-Joule heating effects

    Energy Technology Data Exchange (ETDEWEB)

    Karczemska, Anna T., E-mail: anna.karczemska@p.lodz.pl [Technical University of Lodz, Institute of Turbomachinery, 219/223 Wolczanska str., Lodz (Poland); Witkowski, Dariusz [Technical University of Lodz, Institute of Turbomachinery, 219/223 Wolczanska str., Lodz (Poland); Ralchenko, Victor, E-mail: ralchenko@nsc.gpi.ru [General Physics Institute, Russian Academy of Science, 38 Vavilov str., Moscow (Russian Federation); Bolshakov, Andrey; Sovyk, Dmitry [General Physics Institute, Russian Academy of Science, 38 Vavilov str., Moscow (Russian Federation); Lysko, Jan M., E-mail: jmlysko@ite.waw.pl [Institute of Electron Technology, Al. Lotnikow 32/46, 02-668 Warsaw (Poland); Fijalkowski, Mateusz, E-mail: petr.louda@vslib.cz [Technical University of Liberec, Faculty of Mechanical Engineering (Czech Republic); Bodzenta, Jerzy, E-mail: jerzy.bodzenta@polsl.pl [Silesian University of Technology, Institute of Physics, 2 Krzywoustego str., 44-100 Gliwice (Poland); Hassard, John, E-mail: j.hassard@imperial.ac.uk [Imperial College of Science, Technology and Medicine, London (United Kingdom)

    2011-03-15

    Microchip electrophoresis (MCE) has become a mature separation technique in the recent years. In the presented research, a polycrystalline diamond electrophoretic microchip was manufactured with a microwave plasma chemical vapour deposition (MPCVD) method. A replica technique (mould method) was used to manufacture microstructures in diamond. A numerical analysis with CoventorWare{sup TM} was used to compare thermal properties during chip electrophoresis of diamond and glass microchips of the same geometries. Temperature distributions in microchips were demonstrated. Thermal, electrical, optical, chemical and mechanical parameters of the polycrystalline diamond layers are advantageous over traditionally used materials for microfluidic devices. Especially, a very high thermal conductivity coefficient gives a possibility of very efficient dissipation of Joule heat from the diamond electrophoretic microchip. This enables manufacturing of a new generation of microdevices.

  10. A MEMS diamond hemispherical resonator

    Science.gov (United States)

    Bernstein, J. J.; Bancu, M. G.; Cook, E. H.; Chaparala, M. V.; Teynor, W. A.; Weinberg, M. S.

    2013-12-01

    In this paper we report the fabrication of hemispherical polycrystalline diamond resonators fabricated on a novel high-temperature glass substrate. The hemispherical resonator gyroscope is one of the most accurate and rugged of the mechanical gyroscopes, and can be operated in either rate or whole-angle mode due to its high degree of symmetry. A fabrication sequence for creating extremely symmetric 3D MEMS hemispheres is presented. Mode shapes and frequencies obtained with a laser vibrometer are shown, as well as curves of Q versus pressure, and the dependence of frequency on anchor size. Fundamental mode frequency matching to gyroscope operation in whole-angle mode.

  11. Epitaxial nucleation of CVD bilayer graphene on copper.

    Science.gov (United States)

    Song, Yenan; Zhuang, Jianing; Song, Meng; Yin, Shaoqian; Cheng, Yu; Zhang, Xuewei; Wang, Miao; Xiang, Rong; Xia, Yang; Maruyama, Shigeo; Zhao, Pei; Ding, Feng; Wang, Hongtao

    2016-12-08

    Bilayer graphene (BLG) has emerged as a promising candidate for next-generation electronic applications, especially when it exists in the Bernal-stacked form, but its large-scale production remains a challenge. Here we present an experimental and first-principles calculation study of the epitaxial chemical vapor deposition (CVD) nucleation process for Bernal-stacked BLG growth on Cu using ethanol as a precursor. Results show that a carefully adjusted flow rate of ethanol can yield a uniform BLG film with a surface coverage of nearly 90% and a Bernal-stacking ratio of nearly 100% on ordinary flat Cu substrates, and its epitaxial nucleation of the second layer is mainly due to the active CH3 radicals with the presence of a monolayer-graphene-covered Cu surface. We believe that this nucleation mechanism will help clarify the formation of BLG by the epitaxial CVD process, and lead to many new strategies for scalable synthesis of graphene with more controllable structures and numbers of layers.

  12. Oxide Dispersion Strengthened Iron Aluminide by CVD Coated Powders

    Energy Technology Data Exchange (ETDEWEB)

    Asit Biswas Andrew J. Sherman

    2006-09-25

    This I &I Category2 program developed chemical vapor deposition (CVD) of iron, aluminum and aluminum oxide coated iron powders and the availability of high temperature oxidation, corrosion and erosion resistant coating for future power generation equipment and can be used for retrofitting existing fossil-fired power plant equipment. This coating will provide enhanced life and performance of Coal-Fired Boilers components such as fire side corrosion on the outer diameter (OD) of the water wall and superheater tubing as well as on the inner diameter (ID) and OD of larger diameter headers. The program also developed a manufacturing route for readily available thermal spray powders for iron aluminide coating and fabrication of net shape component by powder metallurgy route using this CVD coated powders. This coating can also be applid on jet engine compressor blade and housing, industrial heat treating furnace fixtures, magnetic electronic parts, heating element, piping and tubing for fossil energy application and automotive application, chemical processing equipment , heat exchanger, and structural member of aircraft. The program also resulted in developing a new fabrication route of thermal spray coating and oxide dispersion strengthened (ODS) iron aluminide composites enabling more precise control over material microstructures.

  13. Organic solar cells using CVD-grown graphene electrodes

    Science.gov (United States)

    Kim, Hobeom; Bae, Sang-Hoon; Han, Tae-Hee; Lim, Kyung-Geun; Ahn, Jong-Hyun; Lee, Tae-Woo

    2014-01-01

    We report on the development of flexible organic solar cells (OSCs) incorporating graphene sheets synthesized by chemical vapor deposition (CVD) as transparent conducting electrodes on polyethylene terephthalate (PET) substrates. A key barrier that must be overcome for the successful fabrication of OSCs with graphene electrodes is the poor-film properties of water-based poly(3,4-ethylenedioxythiphene):poly(styrenesulfonate) (PEDOT:PSS) when coated onto hydrophobic graphene surfaces. To form a uniform PEDOT:PSS film on a graphene surface, we added perfluorinated ionomers (PFI) to pristine PEDOT:PSS to create ‘GraHEL’, which we then successfully spin coated onto the graphene surface. We systematically investigated the effect of number of layers in layer-by-layer stacked graphene anode of an OSC on the performance parameters including the open-circuit voltage (Voc), short-circuit current (Jsc), and fill factor (FF). As the number of graphene layers increased, the FF tended to increase owing to lower sheet resistance, while Jsc tended to decrease owing to the lower light absorption. In light of this trade-off between sheet resistance and transmittance, we determined that three-layer graphene (3LG) represents the best configuration for obtaining the optimal power conversion efficiency (PCE) in OSC anodes, even at suboptimal sheet resistances. We finally developed efficient, flexible OSCs with a PCE of 4.33%, which is the highest efficiency attained so far by an OSC with CVD-grown graphene electrodes to the best of our knowledge.

  14. PE-CVD fabrication of germanium nanoclusters for memory applications

    Energy Technology Data Exchange (ETDEWEB)

    Duerkop, T. [Institut fuer Materialien und Bauelemente der Elektronik, Leibniz Universitaet Hannover, Appelstrasse 11a, 30167 Hannover (Germany)], E-mail: duerkop@mbe.uni-hannover.de; Bugiel, E. [Institut fuer Materialien und Bauelemente der Elektronik, Leibniz Universitaet Hannover, Appelstrasse 11a, 30167 Hannover (Germany); Costina, I. [IHP GmbH, Im Technologiepark 25, 15236 Frankfurt (Oder) (Germany); Ott, A.; Peibst, R.; Hofmann, K.R. [Institut fuer Materialien und Bauelemente der Elektronik, Leibniz Universitaet Hannover, Appelstrasse 11a, 30167 Hannover (Germany)

    2008-02-15

    We have investigated Ge nanoclusters (Ge-NC) embedded in silicon dioxide, whose fundamental properties promise improved characteristics in NC flash memory devices as compared to Si nanoclusters. We present a simple new method, based on plasma-enhanced CVD (PE-CVD) deposition of amorphous Ge (a-Ge) onto SiO{sub 2}, to create gate stacks with embedded Ge-NC at vertically well-controlled positions suitable for use in flash memory devices. This process minimizes the exposure of Ge to environmental influences by depositing a-Ge as well as a SiO{sub 2} cap layer in situ within the same deposition chamber. Subsequent high-temperature anneals compatible with the temperature budget of CMOS processing are used for the actual cluster formation. Variation of annealing temperature and duration of this step as well as the thickness of the initial Ge layer controls the average cluster radius and density, as determined by transmission electron microscopy (TEM). Measurements of electrical properties show the capability of samples with NC to store charge.

  15. CVD Rhenium Engines for Solar-Thermal Propulsion Systems

    Science.gov (United States)

    Williams, Brian E.; Fortini, Arthur J.; Tuffias, Robert H.; Duffy, Andrew J.; Tucker, Stephen P.

    1999-01-01

    Solar-thermal upper-stage propulsion systems have the potential to provide specific impulse approaching 900 seconds, with 760 seconds already demonstrated in ground testing. Such performance levels offer a 100% increase in payload capability compared to state-of-the-art chemical upper-stage systems, at lower cost. Although alternatives such as electric propulsion offer even greater performance, the 6- to 18- month orbital transfer time is a far greater deviation from the state of the art than the one to two months required for solar propulsion. Rhenium metal is the only material that is capable of withstanding the predicted thermal, mechanical, and chemical environment of a solar-thermal propulsion device. Chemical vapor deposition (CVD) is the most well-established and cost-effective process for the fabrication of complex rhenium structures. CVD rhenium engines have been successfully constructed for the Air Force ISUS program (bimodal thrust/electricity) and the NASA Shooting Star program (thrust only), as well as under an Air Force SBIR project (thrust only). The bimodal engine represents a more long-term and versatile approach to solar-thermal propulsion, while the thrust-only engines provide a potentially lower weight/lower cost and more near-term replacement for current upper-stage propulsion systems.

  16. CVD-graphene growth on different polycrystalline transition metals

    Directory of Open Access Journals (Sweden)

    M. P. Lavin-Lopez

    2017-01-01

    Full Text Available The chemical vapor deposition (CVD graphene growth on two polycrystalline transition metals (Ni and Cu was investigated in detail using Raman spectroscopy and optical microscopy as a way to synthesize graphene of the highest quality (i.e. uniform growth of monolayer graphene, which is considered a key issue for electronic devices. Key CVD process parameters (reaction temperature, CH4/H2flow rate ratio, total flow of gases (CH4+H2, reaction time were optimized for both metals in order to obtain the highest graphene uniformity and quality. The conclusions previously reported in literature about the performance of low and high carbon solubility metals in the synthesis of graphene and their associated reaction mechanisms, i.e. surface depositionand precipitation on cooling, respectively, was not corroborated by the results obtained in this work. Under the optimal reaction conditions, a large percentage of monolayer graphene was obtained over the Ni foil since the carbon saturation was not complete, allowing carbon atoms to be stored in the bulk metal, which could diffuse forming high quality monolayer graphene at the surface. However, under the optimal reaction conditions, the formation of a non-uniform mixture of few layers and multilayer graphene on the Cu foil was related to the presence of an excess of active carbon atoms on the Cu surface.

  17. Analysis of Residual Thermal Stress in CVD-W Coating as Plasma Facing Material

    Institute of Scientific and Technical Information of China (English)

    朱大焕; 王坤; 王先平; 陈俊凌; 方前锋

    2012-01-01

    Chemical vapor deposition-tungsten (CVD-W) coating covering the surface of the plasma facing component (PFC) is an effective method to implement the tungsten material as plasma facing material (PFM) in fusion devices. Residual thermal stress in CVD-W coating due to thermal mismatch between coating and substrate was successfully simulated by using a finite element method (ANSYS 10.0 code). The deposition parametric effects, i.e., coating thickness and deposition temperature, and interlayer were investigated to get a description of the residual thermal stress in the CVD-W coating-substrate system. And the influence of the substrate materials on the generation of residual thermal stress in the CVD-W coating was analyzed with respect to the CVD-W coating application as PFM. This analysis is beneficial for the preparation and application of CVD-W coating.

  18. Analysis of Residual Thermal Stress in CVD-W Coating as Plasma Facing Material

    Science.gov (United States)

    Zhu, Dahuan; Wang, Kun; Wang, Xianping; Chen, Junling; Fang, Qianfeng

    2012-07-01

    Chemical vapor deposition-tungsten (CVD-W) coating covering the surface of the plasma facing component (PFC) is an effective method to implement the tungsten material as plasma facing material (PFM) in fusion devices. Residual thermal stress in CVD-W coating due to thermal mismatch between coating and substrate was successfully simulated by using a finite element method (ANSYS 10.0 code). The deposition parametric effects, i.e., coating thickness and deposition temperature, and interlayer were investigated to get a description of the residual thermal stress in the CVD-W coating-substrate system. And the influence of the substrate materials on the generation of residual thermal stress in the CVD-W coating was analyzed with respect to the CVD-W coating application as PFM. This analysis is beneficial for the preparation and application of CVD-W coating.

  19. Severe signal loss in diamond beam loss monitors in high particle rate environments by charge trapping in radiation-induced defects

    Energy Technology Data Exchange (ETDEWEB)

    Kassel, Florian; Boer, Wim de [Institute for Experimental Nuclear Physics (IEKP), KIT, Karlsruhe (Germany); Guthoff, Moritz; Dabrowski, Anne [CERN, Meyrin (Switzerland)

    2016-10-15

    The beam condition monitoring leakage (BCML) system is a beam monitoring device in the compact muon solenoid (CMS) experiment at the large hadron collider (LHC). As detectors 32 poly-crystalline (pCVD) diamond sensors are positioned in rings around the beam pipe. Here, high particle rates occur from the colliding beams scattering particles outside the beam pipe. These particles cause defects, which act as traps for the ionization, thus reducing the charge collection efficiency (CCE). However, the loss in CCE was much more severe than expected from low rate laboratory measurements and simulations, especially in single-crystalline (sCVD) diamonds, which have a low initial concentration of defects. After an integrated luminosity of a few fb{sup -1} corresponding to a few weeks of LHC operation, the CCE of the sCVD diamonds dropped by a factor of five or more and quickly approached the poor CCE of pCVD diamonds. The reason why in real experiments the CCE is much worse than in laboratory experiments is related to the ionization rate. At high particle rates the trapping rate of the ionization is so high compared with the detrapping rate, that space charge builds up. This space charge reduces locally the internal electric field, which in turn increases the trapping rate and recombination and hence reduces the CCE in a strongly non-linear way. A diamond irradiation campaign was started to investigate the rate-dependent electrical field deformation with respect to the radiation damage. Besides the electrical field measurements via the transient current technique (TCT), the CCE was measured. The experimental results were used to create an effective deep trap model that takes the radiation damage into account. Using this trap model, the rate-dependent electrical field deformation and the CCE were simulated with the software SILVACO TCAD. The simulation, tuned to rate-dependent measurements from a strong radioactive source, was able to predict the non-linear decrease of the

  20. Optical investigations on the wide bandgap semiconductors diamond and aluminum nitride

    Energy Technology Data Exchange (ETDEWEB)

    Teofilov, Nikolai

    2007-07-01

    In the context of this thesis, new results about optical defects and intrinsic properties of diamond, AlN and AlGaN alloys have been obtained. The main experimental techniques used were low temperature cathodoluminescence and photoluminescence spectroscopy. First, different aspects of intentional and background doping of diamond were discussed. Thus, the most commonly observed green luminescence emission from boron doped HPHT diamonds has been studied by means of temperature dependent CL in a wide temperature range from 10 K to 450 K. One further subject, addressing deep defect nitrogen related luminescence was a study of nitrogen addition in combustion flame grown CVD diamond layers. Two further topics concern intrinsic excitations in diamond, free excitons and electron-hole drops. Several important parameters like the critical density, the critical temperature, and the low-temperature density inside the drops were evaluated. The ground state density of the electron-hole condensate in diamond is about {approx} 42 times larger than that in Si, and the critical temperature takes very high values in the range of 165K.. 173K. Cathodoluminescence investigations on epitaxial wurtzite AlN layers grown on sapphire, SiC, and Si substrates, have shown that although the material is generally of good optical quality, deep level luminescence are still dominating the spectra. Relatively sharp near-band-edge transitions have been observed in all three samples that exhibit significantly reduced line widths for the AlN/sapphire and the AlN/SiC samples. Much broader emission lines in the near band-gap region have been observed for the first time from the AlN sample grown on Si (111) substrate. Temperature dependent CL measurements and numerical line decompositions reveal complicated substructures in the excitonic lines. The temperature dependence of the energy positions and broadening parameters of the transition have been studied and compared with the other materials. Epitaxial Al