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Sample records for crystal synthetic diamond

  1. Lateral IBIC characterization of single crystal synthetic diamond detectors

    CERN Document Server

    Giudice, A Lo; Manfredotti, C; Marinelli, M; Milani, E; Picollo, F; Prestopino, G; Re, A; Rigato, V; Verona, C; Verona-Rinati, G; Vittone, E

    2016-01-01

    In order to evaluate the charge collection efficiency (CCE) profile of single-crystal diamond devices based on a p type/intrinsic/metal configuration, a lateral Ion Beam Induced Charge (IBIC) analysis was performed over their cleaved cross sections using a 2 MeV proton microbeam. CCE profiles in the depth direction were extracted from the cross-sectional maps at variable bias voltage. IBIC spectra relevant to the depletion region extending beneath the frontal Schottky electrode show a 100% CCE, with a spectral resolution of about 1.5%. The dependence of the width of the high efficiency region from applied bias voltage allows the constant residual doping concentration of the active region to be evaluated. The region where the electric field is absent shows an exponentially decreasing CCE profile, from which it is possible to estimate the diffusion length of the minority carriers by means of a drift-diffusion model.

  2. ESR studies of high-energy phosphorus-ion implanted synthetic diamond crystals

    Energy Technology Data Exchange (ETDEWEB)

    Isoya, J. [University of Library and Information Science, Tsukuba, Ibaraki (Japan); Kanda, H.; Morita, Y.; Ohshima, T.

    1997-03-01

    Phosphorus is among potential n-type dopants in diamond. High pressure synthetic diamond crystals of type IIa implanted with high energy (9-18 MeV) phosphorus ions have been studied by using electron spin resonance (ESR) technique. The intensity and the linewidth of the ESR signal attributed to the dangling bond of the amorphous phase varied with the implantation dose, suggesting the nature of the amorphization varies with the dose. The ESR signals of point defects have been observed in the low dose as-implanted crystals and in the high dose crystals annealed at high temperature and at high pressure. (author)

  3. A novel synthetic single crystal diamond device for in vivo dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Marinelli, Marco; Prestopino, G., E-mail: giuseppe.prestopino@uniroma2.it; Tonnetti, A.; Verona, C.; Verona-Rinati, G. [INFN–Dipartimento di Ingegneria Industriale, Università di Roma “Tor Vergata,” Via del Politecnico 1, Roma 00133 (Italy); Falco, M. D.; Bagalà, P. [Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, Tor Vergata University General Hospital, Viale Oxford 81, Roma 00133 (Italy); Pimpinella, M.; Guerra, A. S.; De Coste, V. [Istituto Nazionale di Metrologia delle Radiazioni Ionizzanti, ENEA-INMRI C R Casaccia, Via Anguillarese 301, Roma 00123 (Italy)

    2015-08-15

    Purpose: Aim of the present work is to evaluate the synthetic single crystal diamond Schottky photodiode developed at the laboratories of “Tor Vergata” University in Rome in a new dosimeter configuration specifically designed for offline wireless in vivo dosimetry (IVD) applications. Methods: The new diamond based dosimeter, single crystal diamond detector (SCDD-iv), consists of a small unwired detector and a small external reading unit that can be connected to commercial electrometers for getting the detector readout after irradiation. Two nominally identical SCDD-iv dosimeter prototypes were fabricated and tested. A basic dosimetric characterization of detector performances relevant for IVD application was performed under irradiation with {sup 60}Co and 6 MV photon beams. Preirradiation procedure, response stability, short and long term reproducibility, leakage charge, fading effect, linearity with dose, dose rate dependence, temperature dependence, and angular response were investigated. Results: The SCDD-iv is simple, with no cables linked to the patient and the readout is immediate. The range of response with dose has been tested from 1 up to 12 Gy; the reading is independent of the accumulated dose and dose rate independent in the range between about 0.5 and 5 Gy/min; its temperature dependence is within 0.5% between 25 and 38 °C, and its directional dependence is within 2% from 0° to 90°. The combined relative standard uncertainty of absorbed dose to water measurements is estimated lower than the tolerance and action level of 5%. Conclusions: The reported results indicate the proposed novel offline dosimeter based on a synthetic single crystal diamond Schottky photodiode as a promising candidate for in vivo dosimetry applications with photon beams.

  4. Development of a synthetic single crystal diamond dosimeter for dose measurement of clinical proton beams

    Science.gov (United States)

    Moignier, Cyril; Tromson, Dominique; de Marzi, Ludovic; Marsolat, Fanny; García Hernández, Juan Carlos; Agelou, Mathieu; Pomorski, Michal; Woo, Romuald; Bourbotte, Jean-Michel; Moignau, Fabien; Lazaro, Delphine; Mazal, Alejandro

    2017-07-01

    The scope of this work was to develop a synthetic single crystal diamond dosimeter (SCDD-Pro) for accurate relative dose measurements of clinical proton beams in water. Monte Carlo simulations were carried out based on the MCNPX code in order to investigate and reduce the dose curve perturbation caused by the SCDD-Pro. In particular, various diamond thicknesses were simulated to evaluate the influence of the active volume thickness (e AV) as well as the influence of the addition of a front silver resin (250 µm in thickness in front of the diamond crystal) on depth-dose curves. The simulations indicated that the diamond crystal alone, with a small e AV of just 5 µm, already affects the dose at Bragg peak position (Bragg peak dose) by more than 2% with respect to the Bragg peak dose deposited in water. The optimal design that resulted from the Monte Carlo simulations consists of a diamond crystal of 1 mm in width and 150 µm in thickness with the front silver resin, enclosed by a water-equivalent packaging. This design leads to a deviation between the Bragg peak dose from the full detector modeling and the Bragg peak dose deposited in water of less than 1.2%. Based on those optimizations, an SCDD-Pro prototype was built and evaluated in broad passive scattering proton beams. The experimental evaluation led to probed SCDD-Pro repeatability, dose rate dependence and linearity, that were better than 0.2%, 0.4% (in the 1.0-5.5 Gy min-1 range) and 0.4% (for dose higher than 0.05 Gy), respectively. The depth-dose curves in the 90-160 MeV energy range, measured with the SCDD-Pro without applying any correction, were in good agreement with those measured using a commercial IBA PPC05 plane-parallel ionization chamber, differing by less than 1.6%. The experimental results confirmed that this SCDD-Pro is suitable for measurements with standard electrometers and that the depth-dose curve perturbation is negligible, with no energy dependence and no significant dose rate

  5. Multistrip synthetic single-crystal-diamond photodiode based on a p-type/intrinsic/Schottky metal transverse configuration

    Science.gov (United States)

    Ciancaglioni, I.; Marinelli, Marco; Milani, E.; Prestopino, G.; Verona, C.; Verona-Rinati, G.; Angelone, M.; Pillon, M.; Dolbnya, I.; Sawhney, K.; Tartoni, N.

    2011-04-01

    A synthetic multistrip single-crystal-diamond detector based on a p-type/intrinsic diamond/Schottky metal transverse configuration, operating at zero-bias voltage, was developed. The device was characterized at the Diamond Light Source synchrotron in Harwell (UK) under monochromatic high-flux X-ray beams from 6 to 20 keV and a micro-focused 10 keV beam with a spot size of ~3 μm. No significant pixel-to-pixel variation of both spectral responsivity and time response, high spatial resolution and good signal uniformity along each strip were found, suggesting the tested device structure as a promising sensor for X-ray and UV radiation imaging.

  6. 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.

  7. Evaluation of a synthetic single-crystal diamond detector for relative dosimetry on the Leksell Gamma Knife Perfexion radiosurgery system

    Energy Technology Data Exchange (ETDEWEB)

    Mancosu, Pietro; Reggiori, Giacomo, E-mail: giacomo.reggiori@humanitas.it; Stravato, Antonella; Gaudino, Anna; Lobefalo, Francesca; Palumbo, Valentina; Tomatis, Stefano [Physics Service of Radiation Oncology Department, Clinical and Research Center, Rozzano, Milan 20098 (Italy); Navarria, Piera; Ascolese, Anna; Scorsetti, Marta [Radiation Oncology Department, Humanitas Clinical and Research Center, Rozzano, Milan 20089 (Italy); Picozzi, Piero [Neurosurgery Department, Humanitas Clinical and Research Center, Rozzano, Milan 20089 (Italy); Marinelli, Marco; Verona-Rinati, Gianluca [Dipartimento di Ingegneria Industriale, Università di Roma Tor Vergata, Roma 00133 (Italy)

    2015-09-15

    Purpose: To evaluate the new commercial PTW-60019 synthetic single-crystal microDiamond detector (PTW, Freiburg, Germany) for relative dosimetry measurements on a clinical Leksell Gamma Knife Perfexion radiosurgery system. Methods: Detector output ratios (DORs) for 4 and 8 mm beams were measured using a microDiamond (PTW-60019), a stereotactic unshielded diode [IBA stereotactic field detector (SFD)], a shielded diode (IBA photon field detector), and GafChromic EBT3 films. Both parallel and transversal acquisition directions were considered for PTW-60019 measurements. Measured DORs were compared to the new output factor reference values for Gamma Knife Perfexion (0.814 and 0.900 for 4 and 8 mm, respectively). Profiles in the three directions were also measured for the 4 mm beam to evaluate full width at half maximum (FWHM) and penumbra and to compare them with the corresponding Leksell GammaPlan profiles. Results: FWHM and penumbra for PTW-60019 differed from the calculated values by less than 0.2 and 0.3 mm, for the parallel and transversal acquisitions, respectively. GafChromic films showed FWHM and penumbra within 0.1 mm. The output ratio obtained with the PTW-60019 for the 4 mm field was 1.6% greater in transverse direction compared to the nominal value. Comparable differences up to 0.8% and 1.0% for, respectively, GafChromic films and SFD were found. Conclusions: The microDiamond PTW-60019 is a suitable detector for commissioning and routine use of Gamma Knife with good agreement of both DORs and profiles in the three directions.

  8. Behavior of crystal defects in synthetic type-IIa single-crystalline diamond at high temperatures under normal pressure

    Science.gov (United States)

    Tatsumi, Natsuo; Tamasaku, Kenji; Ito, Toshimichi; Sumiya, Hitoshi

    2017-01-01

    The behavior of dislocation lines (DLs) and stacking faults (SFs) in synthetic type-IIa single-crystalline diamond at high temperatures under normal pressure has been investigated. After annealing the diamond at 1500 °C for 60 min in pure N2 atmosphere, straight DLs were bent to converge to fewer curved dislocation bundles, so that some of the stacking faults were extinct while new DLs appeared at the edges of the removed SFs. These results indicate that SFs in the diamond examined belong to the Shockley type, and that the Shockley partials changed to a perfect dislocation. From this result, the following generation mechanism has been proposed for SFs in diamond. On one hand, because [112] dislocations in the (111) growth sector are contained in the slip plane labelled as (1 ̅ 1 ̅ 1), one perfect dislocation tends to be split into two Shockley partials and a SF when an appropriate stress is applied. On the other hand, the angle between the {111} slip plane and the direction of bundled dislocations in the (001) growth sector is as high as 54.7°, so that a perfect dislocation can hardly slip into partial dislocations. Thus, SFs exist only in the (111) growth sector of type IIa diamond.

  9. Comparison of natural and synthetic diamond X-ray detectors.

    Science.gov (United States)

    Lansley, S P; Betzel, G T; Metcalfe, P; Reinisch, L; Meyer, J

    2010-12-01

    Diamond detectors are particularly well suited for dosimetry applications in radiotherapy for reasons including near-tissue equivalence and high-spatial resolution resulting from small sensitive volumes. However, these detectors have not become commonplace due to high cost and poor availability arising from the need for high-quality diamond. We have fabricated relatively cheap detectors from commercially-available synthetic diamond fabricated using chemical vapour deposition. Here, we present a comparison of one of these detectors with the only commercially-available diamond-based detector (which uses a natural diamond crystal). Parameters such as the energy dependence and linearity of charge with dose were investigated at orthovoltage energies (50-250 kV), and dose-rate dependence of charge at linear accelerator energy (6 MV). The energy dependence of a synthetic diamond detector was similar to that of the natural diamond detector, albeit with slightly less variation across the energy range. Both detectors displayed a linear response with dose (at 100 kV) over the limited dose range used. The sensitivity of the synthetic diamond detector was 302 nC/Gy, compared to 294 nC/Gy measured for the natural diamond detector; however, this was obtained with a bias of 246.50 V compared to a bias of 61.75 V used for the natural diamond detector. The natural diamond detector exhibited a greater dependency on dose-rate than the synthetic diamond detector. Overall, the synthetic diamond detector performed well in comparison to the natural diamond detector.

  10. Shape analysis of synthetic diamond

    CERN Document Server

    Mullan, C

    1997-01-01

    Two-dimensional images of synthetic industrial diamond particles were obtained using a camera, framegrabber and PC-based image analysis software. Various methods for shape quantification were applied, including two-dimensional shape factors, Fourier series expansion of radius as a function of angle, boundary fractal analysis, polygonal harmonics, and comer counting methods. The shape parameter found to be the most relevant was axis ratio, defined as the ratio of the minor axis to the major axis of the ellipse with the same second moments of area as the particle. Axis ratio was used in an analysis of the sorting of synthetic diamonds on a vibrating table. A model was derived based on the probability that a particle of a given axis ratio would travel to a certain bin. The model described the sorting of bulk material accurately but it was found not to be applicable if the shape mix of the feed material changed dramatically. This was attributed to the fact that the particle-particle interference was not taken int...

  11. Dynamic compression of synthetic diamond windows (final report for LDRD project 93531).

    Energy Technology Data Exchange (ETDEWEB)

    Dolan, Daniel H.,

    2008-09-01

    Diamond is an attractive dynamic compression window for many reasons: high elastic limit,large mechanical impedance, and broad transparency range. Natural diamonds, however, aretoo expensive to be used in destructive experiments. Chemical vapor deposition techniquesare now able to produce large single-crystal windows, opening up many potential dynamiccompression applications. This project studied the behavior of synthetic diamond undershock wave compression. The results suggest that synthetic diamond could be a usefulwindow in this field, though complete characterization proved elusive.3

  12. Anisotropy of synthetic diamond in catalytic etching using iron powder

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Junsha [College of Materials Science and Engineering, Hunan University, Hunan 410082 (China); Department of Mechanical Engineering, Keio University, Yokohama 223-8522 (Japan); Wan, Long, E-mail: wanlong1799@163.com [College of Materials Science and Engineering, Hunan University, Hunan 410082 (China); Chen, Jing [College of Materials Science and Engineering, Hunan University, Hunan 410082 (China); Yan, Jiwang [Department of Mechanical Engineering, Keio University, Yokohama 223-8522 (Japan)

    2015-08-15

    Highlights: • Synthetic diamond crystallites were etched using iron without requiring hydrogen. • The effect of temperature on the etching behaviour was demonstrated. • The anisotropy of etching on different crystal planes was investigated. • The extent of etching on diamond surface was examined quantitatively. • A schematic model for diamond etching by iron is being proposed. - Abstract: This paper demonstrated a novel technique for catalytic etching of synthetic diamond crystallites using iron (Fe) powder without flowing gas. The effect of temperature on the etching behaviour on different crystal planes of diamond was investigated. The surface morphology and surface roughness of the processed diamond were examined by scanning electron microscope (SEM) and laser-probe surface profiling. In addition, the material composition of the Fe-treated diamond was characterized using micro-Raman spectroscopy and the distribution of chemical elements and structural changes on Fe-loaded diamond surfaces were analyzed by energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD), respectively. Results showed that at the same temperature the {1 0 0} plane was etched faster than the {1 1 1} plane, and that the etching rate of both {1 0 0} and {1 1 1} plane increased with temperature. The etch pits on {1 0 0} plane were reversed pyramid with flat {1 1 1} walls, while the etch holes on {1 1 1} plane were characterized with flat bottom. It was also demonstrated that graphitization of diamond and subsequent carbon diffusion in molten iron were two main factors resulting in the removal of carbon from the diamond surface.

  13. 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.

  14. Spotting a fake[Telling natural and synthetic diamonds apart

    Energy Technology Data Exchange (ETDEWEB)

    Lawson, S. [Diamond Trading Company, Maidenhead, Berkshire (United Kingdom)]. E-mail: simon.lawson@dtc.com

    2006-06-15

    Diamonds are highly prized for their dazzling appearance and hardness, but would you be able to spot one that had been created in the laboratory? Simon Lawson describes how physics-based techniques can distinguish between natural and synthetic stones. For the last 50 years or so we have been able to make synthetic diamonds that replicate the superlative physical and chemical properties of natural diamonds, and these are used largely for industrial applications. But in the mind of the consumer, there is far more to a diamond than its hardness or brilliance. Research commissioned by the Diamond Trading Company (DTC) has shown that 94% of women surveyed prefer natural diamonds over synthetic ones as a symbol of love, possibly as a result of the immense age of natural stones. One of the key research activities at the DTC is therefore to ensure that synthetic diamonds can be spotted easily. (U.K.)

  15. Fracture behavior of HPHT synthetic diamond with micrometers metallic inclusions

    Institute of Scientific and Technical Information of China (English)

    He-sheng LI; Yong-xin QI; Yuan-pei ZHANG; Mu-sen LI

    2009-01-01

    The fracture behavior of the diamond single cwstals with metallic inclusions was investigated in the present paper.Single diamond crystals with metallic inclusions were formed by a special process with high pressure and high tempemture(HPHT).The inclusions trapped in the diamond were characterized mainly to be metallic carbide of(Fe,Ni)23C6 or Fe3C and solid solution of y-(Fe,Ni)by transmission electronic microscopy(TEM).The grain size of the inclusions is about micrometers. The fracture characteristics of the diamond single crystals,after compression and heating,were investigated by optical microscopy (OM) and scanning electron microscopy (SEM).The fracture sections of the compressed and heated diamonds were found to be parallel to the (111)plane. The interface of the inclusions and diamond is deduced to be the key factor and the original region Of the fracture formation. Mechanisms of the fracture behavior ofthe HPHT synthesized diamonds are discussed.

  16. Response function of single crystal synthetic diamond detectors to 1-4 MeV neutrons for spectroscopy of D plasmas

    Science.gov (United States)

    Rebai, M.; Giacomelli, L.; Milocco, A.; Nocente, M.; Rigamonti, D.; Tardocchi, M.; Camera, F.; Cazzaniga, C.; Chen, Z. J.; Du, T. F.; Fan, T. S.; Giaz, A.; Hu, Z. M.; Marchi, T.; Peng, X. Y.; Gorini, G.

    2016-11-01

    A Single-crystal Diamond (SD) detector prototype was installed at Joint European Torus (JET) in 2013 and the achieved results have shown its spectroscopic capability of measuring 2.5 MeV neutrons from deuterium plasmas. This paper presents measurements of the SD response function to monoenergetic neutrons, which is a key point for the development of a neutron spectrometer based on SDs and compares them with Monte Carlo simulations. The analysis procedure allows for a good reconstruction of the experimental results. The good pulse height energy resolution (equivalent FWHM of 80 keV at 2.5 MeV), gain stability, insensitivity to magnetic field, and compact size make SDs attractive as compact neutron spectrometers of high flux deuterium plasmas, such as for instance those needed for the ITER neutron camera.

  17. 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.

  18. 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.

  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. Relative electron dosimetry using a synthetic diamond probe

    CERN Document Server

    Merwe, D G

    1999-01-01

    Implementation of Bragg-Gray Cavity Theory in electron dosimetry is complicated by the fact that most commercial detector volumes behave as small field inhomogeneities. Several correction factors are necessary to establish the absorbed dose at a particular point in a homogenous tissue-equivalent phantom. The energy dependence of air and the replacement effects introduced as a result of air ionization chambers' construction and size, increase the uncertainty of electron beam calibrations. Preliminary relative dose measurements performed with a prototype synthetic diamond are presented here. Theoretically, the radiation response of diamond, synthetic or natural, has negligible energy dependence. The sensitivity and small size of the probe makes it an excellent candidate for measurements in fields of high dose gradient.

  1. Analysis of the carbon source for diamond crystal growth

    Institute of Scientific and Technical Information of China (English)

    LI Li; XU Bin; LI MuSen

    2008-01-01

    The lattice constants of diamond and graphite at high pressure and high temperature (HPHT) were calculated on the basis of linear expansion coefficient and elastic constant. According to the empirical electron theory of solids and molecules (EET), the valence electron structures (VESs) of diamond, graphite crystal and their common planes were calculated. The relationship between diamond and graphite structure was analyzed based on the boundary condition of the improved Thomas-Fermi-Dirac theory by Cheng (TFDC). It was found that the electron densities of common planes in graphite were not continuous with those of planes in diamond at the first order of approximation. The results show that during the course of diamond single crystal growth at HPHT with metal catalyst, the carbon sources forming diamond structure do not come from the graphite structure directly. The diamond growth mechanism was discussed from the viewpoint of valence electron structure.

  2. 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...

  3. Synthesis and characterization of p-type boron-doped IIb diamond large single crystals

    Institute of Scientific and Technical Information of China (English)

    Li Shang-Sheng; Ma Hong-An; Li Xiao-Lei; Su Tai-Chao; Huang Guo-Feng; Li Yong; Jia Xiao-Peng

    2011-01-01

    High-quality p-type boron-doped II0b diamond large single crystals are successfully synthesized by the temperature gradient method in a china-type cubic anvil high-pressure apparatus at about 5.5 GPa and 1600 K. The morphologies and surface textures of the synthetic diamond crystals with different boron additive quantities are characterized by using an optical microscope and a scanning electron microscope respectively. The impurities of nitrogen and boron in diamonds are detected by micro Fourier transform infrared technique. The electrical properties including resistivities, Hall coefficients, Hall mobilities and carrier densities of the synthesized samples are measured by a four-point probe and the Hall effect method. The results show that large p-type boron-doped diamond single crystals with few nitrogen impurities have been synthesized. With the increase of quantity of additive boron, some high-index crystal faces such as {113} gradually disappear, and some stripes and triangle pits occur on the crystal surface. This work is helpful for the further research and application of boron-doped semiconductor diamond.

  4. Colloidal crystals with diamond symmetry at optical lengthscales

    Science.gov (United States)

    Wang, Yifan; Jenkins, Ian C.; McGinley, James T.; Sinno, Talid; Crocker, John C.

    2017-02-01

    Future optical materials promise to do for photonics what semiconductors did for electronics, but the challenge has long been in creating the structure they require--a regular, three-dimensional array of transparent microspheres arranged like the atoms in a diamond crystal. Here we demonstrate a simple approach for spontaneously growing double-diamond (or B32) crystals that contain a suitable diamond structure, using DNA to direct the self-assembly process. While diamond symmetry crystals have been grown from much smaller nanoparticles, none of those previous methods suffice for the larger particles needed for photonic applications, whose size must be comparable to the wavelength of visible light. Intriguingly, the crystals we observe do not readily form in previously validated simulations; nor have they been predicted theoretically. This finding suggests that other unexpected microstructures may be accessible using this approach and bodes well for future efforts to inexpensively mass-produce metamaterials for an array of photonic applications.

  5. Colloidal crystals with diamond symmetry at optical lengthscales

    Science.gov (United States)

    Wang, Yifan; Jenkins, Ian C.; McGinley, James T.; Sinno, Talid; Crocker, John C.

    2017-01-01

    Future optical materials promise to do for photonics what semiconductors did for electronics, but the challenge has long been in creating the structure they require—a regular, three-dimensional array of transparent microspheres arranged like the atoms in a diamond crystal. Here we demonstrate a simple approach for spontaneously growing double-diamond (or B32) crystals that contain a suitable diamond structure, using DNA to direct the self-assembly process. While diamond symmetry crystals have been grown from much smaller nanoparticles, none of those previous methods suffice for the larger particles needed for photonic applications, whose size must be comparable to the wavelength of visible light. Intriguingly, the crystals we observe do not readily form in previously validated simulations; nor have they been predicted theoretically. This finding suggests that other unexpected microstructures may be accessible using this approach and bodes well for future efforts to inexpensively mass-produce metamaterials for an array of photonic applications. PMID:28194025

  6. Processing of Photonic Crystal Nanocavity for Quantum Information in Diamond

    CERN Document Server

    Bayn, Igal; Lahav, Alex; Salzman, Joseph; Kalish, Rafi; Fairchild, Barbara A; Prawer, Steven; Barth, Michael; Benson, Oliver; Wolf, Thomas; Siyushev, Petr; Jelezko, Fedor; Wrachtrup, Jorg

    2010-01-01

    The realization of photonic crystals (PC) in diamond is of major importance for the entire field of spintronics based on fluorescent centers in diamond. The processing steps for the case of diamond differ from those commonly used, due to the extreme chemical and mechanical properties of this material. The present work summarizes the state of the art in the realization of PC's in diamond. It is based on the creation of a free standing diamond membrane into which the desired nano-sized patterns are milled by the use of Focused-Ion-Beam (FIB). The optimal fabrication-oriented structure parameters are predicted by simulations. The milling strategies, the method of formation the diamond membrane, recipes for dielectric material-manipulation in FIB and optical characterization constraints are discussed in conjunction with their implication on PC cavity design. The thus produced structures are characterized via confocal photoluminescence.

  7. Nanofluidics of Single-crystal Diamond Nanomechanical Resonators

    CERN Document Server

    Kara, V; Atikian, H; Yakhot, V; Loncar, M; Ekinci, K L

    2015-01-01

    Single-crystal diamond nanomechanical resonators are being developed for countless applications. A number of these applications require that the resonator be operated in a fluid, i.e., a gas or a liquid. Here, we investigate the fluid dynamics of single-crystal diamond nanomechanical resonators in the form of nanocantilevers. First, we measure the pressure-dependent dissipation of diamond nanocantilevers with different linear dimensions and frequencies in three gases, He, N$_2$, and Ar. We observe that a subtle interplay between the length scale and the frequency governs the scaling of the fluidic dissipation. Second, we obtain a comparison of the surface accommodation of different gases on the diamond surface by analyzing the dissipation in the molecular flow regime. Finally, we measure the thermal fluctuations of the nanocantilevers in water, and compare the observed dissipation and frequency shifts with theoretical predictions. These findings set the stage for developing diamond nanomechanical resonators o...

  8. Luminescent properties of diamond single crystals of pyramidal shape

    Science.gov (United States)

    Alekseev, A. M.; Tuyakova, F. T.; Obraztsova, E. A.; Korostylev, E. V.; Klinov, D. V.; Prusakov, K. A.; Malykhin, S. A.; Ismagilov, R. R.; Obraztsov, A. N.

    2016-11-01

    The luminescence properties of needle-like crystals of diamond, obtained by selective oxidation of textured polycrystalline diamond films, are studied. Diamond films were grown by chemical vapor deposition from a methane-hydrogen mixture activated by a DC discharge. The spectra of photo- and cathodoluminescence and the spatial distribution of the intensity of radiation at different wavelengths are obtained for individual needle-like crystals. Based on the spectral characteristics, conclusions are made about the presence of optically active defects containing nitrogen and silicon impurities in their structure, as well as the significant effect of structural defects on their luminescence spectra.

  9. Single Crystal Diamond Needle as Point Electron Source

    Science.gov (United States)

    Kleshch, Victor I.; Purcell, Stephen T.; Obraztsov, Alexander N.

    2016-10-01

    Diamond has been considered to be one of the most attractive materials for cold-cathode applications during past two decades. However, its real application is hampered by the necessity to provide appropriate amount and transport of electrons to emitter surface which is usually achieved by using nanometer size or highly defective crystallites having much lower physical characteristics than the ideal diamond. Here, for the first time the use of single crystal diamond emitter with high aspect ratio as a point electron source is reported. Single crystal diamond needles were obtained by selective oxidation of polycrystalline diamond films produced by plasma enhanced chemical vapor deposition. Field emission currents and total electron energy distributions were measured for individual diamond needles as functions of extraction voltage and temperature. The needles demonstrate current saturation phenomenon and sensitivity of emission to temperature. The analysis of the voltage drops measured via electron energy analyzer shows that the conduction is provided by the surface of the diamond needles and is governed by Poole-Frenkel transport mechanism with characteristic trap energy of 0.2-0.3 eV. The temperature-sensitive FE characteristics of the diamond needles are of great interest for production of the point electron beam sources and sensors for vacuum electronics.

  10. Synthetic thermoelectric materials comprising phononic crystals

    Science.gov (United States)

    El-Kady, Ihab F; Olsson, Roy H; Hopkins, Patrick; Reinke, Charles; Kim, Bongsang

    2013-08-13

    Synthetic thermoelectric materials comprising phononic crystals can simultaneously have a large Seebeck coefficient, high electrical conductivity, and low thermal conductivity. Such synthetic thermoelectric materials can enable improved thermoelectric devices, such as thermoelectric generators and coolers, with improved performance. Such synthetic thermoelectric materials and devices can be fabricated using techniques that are compatible with standard microelectronics.

  11. Low-dissipation cavity optomechanics in single-crystal diamond

    CERN Document Server

    Mitchell, Matthew; Lake, David P; Barclay, Paul E

    2015-01-01

    Single-crystal diamond cavity optomechanical devices are a promising example of a hybrid quantum system: by coupling mechanical resonances to both light and electron spins, they can enable new ways for photons to control solid state qubits. However, creating devices from high quality bulk diamond chips is challenging. Here we demonstrate single-crystal diamond cavity optomechanical devices that can enable photon-phonon-spin coupling. Cavity optomechanical coupling to $2\\,\\text{GHz}$ frequency ($f_\\text{m}$) mechanical resonances is observed. In room temperature ambient conditions, the resonances have a record combination of low dissipation ($Q_\\text{m} > 9000$) and high frequency, with $Q_\\text{m}\\cdot f_\\text{m} \\sim 1.9\\times10^{13}$ sufficient for room temperature single phonon coherence. The system is nearly sideband resolved, and radiation pressure is used to excite $\\sim 31\\,\\text{pm}$ amplitude mechanical self-oscillations that can drive diamond color centre electron spin transitions.

  12. Structural peculiarities of single crystal diamond needles of nanometer thickness

    Science.gov (United States)

    Orekhov, Andrey S.; Tuyakova, Feruza T.; Obraztsova, Ekaterina A.; Loginov, Artem B.; Chuvilin, Andrey L.; Obraztsov, Alexander N.

    2016-11-01

    Diamond is attractive for various applications due to its unique mechanical and optical properties. In particular, single crystal diamond needles with high aspect ratios and sharp apexes of nanometer size are demanded for different types of optical sensors including optically sensing tip probes for scanning microscopy. This paper reports on electron microscopy and Raman spectroscopy characterization of the diamond needles having geometrically perfect pyramidal shapes with rectangular atomically flat bases with (001) crystallography orientation, 2-200 nm sharp apexes, and with lengths from about 10-160 μm. The needles were produced by selective oxidation of (001) textured polycrystalline diamond films grown by chemical vapor deposition. Here we study the types and distribution of defects inside and on the surface of the single crystal diamond needles. We show that sp3 type point defects are incorporated into the volume of the diamond crystal during growth, while the surface of the lateral facets is enriched by multiple extended defects. Nitrogen addition to the reaction mixture results in increase of the growth rate on {001} facets correlated with the rise in the concentration of sp3 type defects.

  13. Interface Instability of Diamond Crystals at High Temperature and High Pressure

    Institute of Scientific and Technical Information of China (English)

    尹龙卫; 李木森; 许斌; 崔建军; 郝兆印

    2002-01-01

    Diamond growth instability at high temperature and high pressure (HPHT) has been elucidated by observing the cellular interface in diamond crystals. The HPHIT diamond crystals grow layer by layer from solution of carbon in the molten catalyst. In the growth of any other crystals from solution, the growth interface is not stable and should be of the greatest significance to understand further the diamond growth mechanism. During the diamond growth, the carbon atoms are delivered to the growing diamond crystal by diffusion through a diamond crystal-solution boundary layer. In front of the boundary layer, there is a narrow constitutional supercooling zone related to the solubility difference between diamond and graphite in the molten catalyst. The diamond growth stability is broken, and the flat or planar growth interface transforms into a cellular interface due to the light supercooling. The phenomenon of solute trails in the diamonds was observed, the formation of solute trails was closely associated with the cellular interface.

  14. 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.

  15. Effects of additive NaN3 on the HPHT synthesis of large single crystal diamond grown by TGM

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this paper,large single crystal diamond with perfect shape and high nitrogen concentration approximately 1671-1742 ppm was successfully synthesized by temperature gradient method (TGM) under high pressure and high temperature (HPHT).The HPHT synthesis conditions were about 5.5 GPa and 1500-1550 K.Sodium azide (NaN3) with different amount was added as the source of nitrogen into the synthesis system of high pure graphite and kovar alloy.The effects of additive NaN3 on crystal growth habit were investigated in detail.The crystal morphology,nitrogen concentration and existing form in synthetic diamond were characterized by means of scanning electron microscope (SEM) and infrared (IR) absorption spectra,respectively.The results show that with an increase of the content of NaN3 added in the synthesis system,the region of synthesis temperature for high-quality diamond becomes narrow,and crystal growth rate is restricted,whereas the nitrogen concentration in synthetic diamond increases.Nitrogen exists in diamond mainly in dispersed form (C-centers) and partially aggregated form (A-centers).The defects occur more frequently on crystal surface when excessive NaN3 is added in the synthesis system.

  16. Electronic properties of graphene-single crystal diamond heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Fang; Thuong Nguyen, Thuong; Golsharifi, Mohammad; Amakubo, Suguru; Jackman, Richard B., E-mail: r.jackman@ucl.ac.uk [London Centre for Nanotechnology and Department of Electronic and Electrical Engineering, University College London, 17-19 Gordon Street, London WC1H 0AH (United Kingdom); Loh, K. P. [Department of Chemistry, National University of Singapore, 3 Science Drive, Singapore 117543 (Singapore)

    2013-08-07

    Single crystal diamond has been used as a substrate to support single layer graphene grown by chemical vapor deposition methods. It is possible to chemically functionalise the diamond surface, and in the present case H-, F-, O-, and N-group have been purposefully added prior to graphene deposition. The electronic properties of the resultant heterostructures vary strongly; a p-type layer with good mobility and a band gap of ∼0.7 eV is created when H-terminated diamond layers are used, whilst a layer with more metallic-like character (high carrier density and low carrier mobility) arises when N(O)-terminations are introduced. Since it is relatively easy to pattern these functional groups on the diamond surface, this suggests that this approach may offer an exciting route to 2D device structures on single layer graphene sheets.

  17. Diamond turning of Si and Ge single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Blake, P.; Scattergood, R.O.

    1988-12-01

    Single-point diamond turning studies have been completed on Si and Ge crystals. A new process model was developed for diamond turning which is based on a critical depth of cut for plastic flow-to-brittle fracture transitions. This concept, when combined with the actual machining geometry for single-point turning, predicts that {open_quotes}ductile{close_quotes} machining is a combined action of plasticity and fracture. Interrupted cutting experiments also provide a meant to directly measure the critical depth parameter for given machining conditions.

  18. Luminescence lifetimes of neutral nitrogen-vacancy centres in synthetic diamond containing nitrogen.

    Science.gov (United States)

    Liaugaudas, G; Davies, G; Suhling, K; Khan, R U A; Evans, D J F

    2012-10-31

    The decay time of luminescence from neutral nitrogen-vacancy (NV(0)) centres in synthetic diamond is reported. The intrinsic luminescence lifetime of NV (0) is measured as τ(r) = 19 ± 2 ns. Neutral substitutional nitrogen atoms (N(S)(0)) are shown to quench luminescence from NV(0) by dipole-dipole resonant energy transfer at a rate such that the transfer time would equal τ(r) if one (N(S)(0)) atom was ~3 nm from the NV(0). In chemical-vapour-deposited diamonds grown with a small nitrogen content, that are brown as a result of vacancy-cluster defects, the decay time of NV(0) equals τ(r) in the as-grown material. However, after annealing at ≥1700 °C to remove the brown colour, luminescence from the NV(0) centres is severely quenched. This effect is suggested to be a result of the destruction of NV(0) centres and the creation of new NV(0) centres localized in vacancy-rich regions of the crystals.

  19. Diamond-Structured Photonic Crystals with Graded Air Spheres Radii

    Directory of Open Access Journals (Sweden)

    Dichen Li

    2012-05-01

    Full Text Available A diamond-structured photonic crystal (PC with graded air spheres radii was fabricated successfully by stereolithography (SL and gel-casting process. The graded radii in photonic crystal were formed by uniting different radii in photonic crystals with a uniform radius together along the Г‑Х direction. The stop band was observed between 26.1 GHz and 34.3 GHz by reflection and transmission measurements in the direction. The result agreed well with the simulation attained by the Finite Integration Technique (FIT. The stop band width was 8.2 GHz and the resulting gap/midgap ratio was 27.2%, which became respectively 141.4% and 161.9% of the perfect PC. The results indicate that the stop band width of the diamond-structured PC can be expanded by graded air spheres radii along the Г‑Х direction, which is beneficial to develop a multi bandpass filter.

  20. Channeling of ultra-relativistic positrons in bent diamond crystals

    Directory of Open Access Journals (Sweden)

    R.G. Polozkov

    2015-06-01

    Full Text Available Results of numerical simulations of channeling of ultra-relativistic positrons are reported for straight and uniformly bent diamond crystals. The projectile trajectories in a crystal are computed using a newly developed module of the MBN Explorer package which simulates classical trajectories in a crystalline medium by integrating the relativistic equations of motion with account for the interaction between the projectile and the crystal atoms. The Monte Carlo method is employed to sample the incoming positrons and to account for thermal vibrations of the crystal atoms. The channeling parameters and emission spectra of incident positrons with a projecti le energy of 855 MeV along C(110 crystallographic planes are calculated for different bending radii of the crystal. Two features of the emission spectrum associated with positron oscillations in a channel and synchrotron radiation are studied as a function of crystal curvature.

  1. 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.

  2. Linear parabolic single-crystal diamond refractive lenses for synchrotron X-ray sources.

    Science.gov (United States)

    Terentyev, Sergey; Polikarpov, Maxim; Snigireva, Irina; Di Michiel, Marco; Zholudev, Sergey; Yunkin, Vyacheslav; Kuznetsov, Sergey; Blank, Vladimir; Snigirev, Anatoly

    2017-01-01

    Linear parabolic diamond refractive lenses are presented, designed to withstand high thermal and radiation loads coming from upgraded accelerator X-ray sources. Lenses were manufactured by picosecond laser treatment of a high-quality single-crystal synthetic diamond. Twelve lenses with radius of curvature at parabola apex R = 200 µm, geometrical aperture A = 900 µm and length L = 1.5 mm were stacked as a compound refractive lens and tested at the ESRF ID06 beamline. A focal spot of size 2.2 µm and a gain of 20 were measured at 8 keV. The lens profile and surface quality were estimated by grating interferometry and X-ray radiography. In addition, the influence of X-ray glitches on the focusing properties of the compound refractive lens were studied.

  3. Design of microcavities in diamond-based photonic crystals by Fourier- and real-space analysis of cavity fields

    CERN Document Server

    Riedrich-Möller, Janine; Becher, Christoph

    2010-01-01

    We present the design of two-dimensional photonic crystal microcavities in thin diamond membranes well suited for coupling of color centers in diamond. By comparing simulated and ideal field distributions in Fourier and real space and by according modification of air hole positions and size, we optimize the cavity structure yielding high quality factors up to Q = 320000 with a modal volume of V = 0.35 (lambda/n)^3. Using the very same approach we also improve previous designs of a small modal volume microcavity in silicon, gaining a factor of 3 in cavity Q. In view of practical realization of photonic crystals in synthetic diamond films, it is necessary to investigate the influence of material absorption on the quality factor. We show that this influence can be predicted by a simple model, replacing time consuming simulations.

  4. 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.

  5. 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.

  6. AG, TL, and IRSL dosimetric properties in X-ray irradiated HPHT diamond crystals

    Energy Technology Data Exchange (ETDEWEB)

    Gil-Tolano, M.I. [Programa de Posgrado, Departamento de Investigacion en Fisica, Universidad de Sonora, A. P. 5-088, Hermosillo, Sonora, 83190, Mexico (Mexico); Melendrez, R.; Lancheros-Olmos, J.C.; Soto-Puebla, D.; Chernov, V.; Pedroza-Montero, M.; Barboza-Flores, M. [Departamento de Investigacion en Fisica, Universidad de Sonora, A. P. 5-088, Hermosillo, Sonora, 83190, Mexico (Mexico); Castaneda, B. [Departamento de Fisica, Universidad de Sonora, Blvd. Luis Encinas y Rosales S/N, Hermosillo, Sonora, 83000, Mexico (Mexico)

    2014-10-15

    HPHT diamonds have been studied for several years for their potential in different applications. In previous studies it has been found that the thermoluminescence (TL) glow curves of ''as-grown'' HPHT diamonds are non-reproducible. In this work, we study the afterglow (AG), thermoluminescent (TL), and optically stimulated luminescence (OSL) response of commercial samples of synthetic HPHT type-Ib diamond crystals exposed to X-ray irradiation (0.75 mA, 35 kV) at a dose rate of 0.624 Gy/s, after a high gamma ({sup 60}Co) dose irradiation of 500 kGy followed by a thermal treatment at 1073 K for 1 h in nitrogen atmosphere. Deconvolution of the TL glow curves shows four peaks, located around 379, 509, 561, and 609 K. The crystals exhibit evident AG recorded for 300 s immediately after X-ray irradiation, due to the thermal emptying of the traps responsible for the low-temperature TL peaks (below 400 K). The stimulation of irradiated crystals with 870-nm light, creates pronounced OSL and destroys all TL peaks with the exception of the high-temperature peak at 609 K. The dose responses of the integrated AG, TL, and OSL are linear in the range of 0.6-5 Gy and saturated at higher doses. The reproducibility of AG, TL, and OSL measurements is about 5%. The fading in the first hour of storage in dark conditions at RT of TL signal of HPHT diamond is mainly associated to the emptying of the traps responsible for the 379-K TL peaks. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Large single-crystal diamond substrates for ionizing radiation detection

    Energy Technology Data Exchange (ETDEWEB)

    Girolami, Marco; Bellucci, Alessandro; Calvani, Paolo; Trucchi, Daniele M. [Istituto di Struttura della Materia (ISM), Consiglio Nazionale delle Ricerche (CNR), Sede Secondaria di Montelibretti, Monterotondo Stazione, Roma (Italy)

    2016-10-15

    The need for large active volume detectors for ionizing radiations and particles, with both large area and thickness, is becoming more and more compelling in a wide range of applications, spanning from X-ray dosimetry to neutron spectroscopy. Recently, 8.0 x 8.0 mm{sup 2} wide and 1.2 mm thick single-crystal diamond plates have been put on the market, representing a first step to the fabrication of large area monolithic diamond detectors with optimized charge transport properties, obtainable up to now only with smaller samples. The more-than-double thickness, if compared to standard plates (typically 500 μm thick), demonstrated to be effective in improving the detector response to highly penetrating ionizing radiations, such as γ-rays. Here we report on the first measurements performed on large active volume single-crystal diamond plates, both in the dark and under irradiation with optical wavelengths (190-1100 nm), X-rays, and radioactive γ-emitting sources ({sup 57}Co and {sup 22}Na). (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Characterization of Growth Hillocks on the Surface of High-Pressure Synthetic Diamond

    Institute of Scientific and Technical Information of China (English)

    尹龙卫; 李木森; 袁泉; 许斌; 郝兆印

    2002-01-01

    Diamond crystals, with dimensions of about 0.5-0.6mm, were synthesized in the presence of Fe-Ni and Fe-Ni Si catalyst solvents under high-pressure-high-temperature (HPHT) conditions. The as-known dendritic pattern was clearly seen on the (111) or (100) planes of diamond single crystals grown using Fe-Ni as a catalyst solvent.However, the conventional dendritic pattern was not observed in diamonds grown in the presence of Fe-Ni-Si alloy catalyst. Trigonal-type, pyramid-type, polygonal-type and rectangular-type growth hillocks were clearly observed on the (111) and (100) surfaces of diamonds grown from the Fe-Ni-Si-C system, and the density of the hillocks is very high at some positions. Clear successive growth layers can also be found on the (111) planes of the high-pressure diamond single crystals grown in the presence of Fe-Ni-Si alloy catalyst. The growth hillocks distributed on the (111) and (100) planes of the diamonds generally occur on or near growth steps, and some of the hillocks terminate at certain solid inclusions and voids. Growth hillocks on the (111) and (100) surfaces directly indicate the spiral growth mechanism under HPHT. A possible formation process for growth hillocks is proposed.

  9. Grey relationship analysis and grey forecasting modeling on thermal stability of synthetic single diamond

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Through analyzing 7 Ib-type samples of synthetic single diamonds by their DTA and TG in air, we ascertained the extrapolated onset temperature on the curves of DTA as the characteristic temperature of their thermal stabilities. Based on the grey system theory, we analyzed 4 factors influential in the thermal stability by the grey relationship analysis, a quantitative method, and derived the grey relationship sequence, that is, the rank of the influence extent of 4 factors on the thermal stability. Furthermore, we established the grey forecasting model, namely GM ( 1,5 ), for predicting the thermal stability of single diamonds with their intrinsic properties, which was then examined by a deviation-probability examination. The results illustrate that it is reasonable to take the Extrapolated Onset Temperature in DTA as the characteristic temperature for thermal stability (TS)of Ib -type synthetic single diamonds. The nitrogen content and grain shape regularity of diamonds are dominating factors. Likewise, grain size and compressive strength are minor factors. In addition, GM (1,5) can be used to predict the thermal stability of Ib-type synthetic single diamonds available. The precision rank of GM( 1,5 ) is‘GOOD’.

  10. Experimental and Theoretical Evidence for Surface-Induced Carbon and Nitrogen Fractionation during Diamond Crystallization at High Temperatures and High Pressures

    Directory of Open Access Journals (Sweden)

    Vadim N. Reutsky

    2017-06-01

    Full Text Available Isotopic and trace element variations within single diamond crystals are widely known from both natural stones and synthetic crystals. A number of processes can produce variations in carbon isotope composition and nitrogen abundance in the course of diamond crystallization. Here, we present evidence of carbon and nitrogen fractionation related to the growing surfaces of a diamond. We document that difference in the carbon isotope composition between cubic and octahedral growth sectors is solvent-dependent and varies from 0.7‰ in a carbonate system to 0.4‰ in a metal-carbon system. Ab initio calculations suggest up to 4‰ instantaneous 13C depletion of cubic faces in comparison to octahedral faces when grown simultaneously. Cubic growth sectors always have lower nitrogen abundance in comparison to octahedral sectors within synthetic diamond crystals in both carbonate and metal-carbon systems. The stability of any particular growth faces of a diamond crystal depends upon the degree of carbon association in the solution. Octahedron is the dominant form in a high-associated solution while the cube is the dominant form in a low-associated solution. Fine-scale data from natural crystals potentially can provide information on the form of carbon, which was present in the growth media.

  11. Thermal diffusion boron doping of single-crystal natural diamond

    Science.gov (United States)

    Seo, Jung-Hun; Wu, Henry; Mikael, Solomon; Mi, Hongyi; Blanchard, James P.; Venkataramanan, Giri; Zhou, Weidong; Gong, Shaoqin; Morgan, Dane; Ma, Zhenqiang

    2016-05-01

    With the best overall electronic and thermal properties, single crystal diamond (SCD) is the extreme wide bandgap material that is expected to revolutionize power electronics and radio-frequency electronics in the future. However, turning SCD into useful semiconductors requires overcoming doping challenges, as conventional substitutional doping techniques, such as thermal diffusion and ion implantation, are not easily applicable to SCD. Here we report a simple and easily accessible doping strategy demonstrating that electrically activated, substitutional doping in SCD without inducing graphitization transition or lattice damage can be readily realized with thermal diffusion at relatively low temperatures by using heavily doped Si nanomembranes as a unique dopant carrying medium. Atomistic simulations elucidate a vacancy exchange boron doping mechanism that occurs at the bonded interface between Si and diamond. We further demonstrate selectively doped high voltage diodes and half-wave rectifier circuits using such doped SCD. Our new doping strategy has established a reachable path toward using SCDs for future high voltage power conversion systems and for other novel diamond based electronic devices. The novel doping mechanism may find its critical use in other wide bandgap semiconductors.

  12. Triangular nanobeam photonic cavities in single crystal diamond

    CERN Document Server

    Bayn, Igal; Salzman, Joseph; Kalish, Rafi

    2011-01-01

    Diamond photonics provides an attractive architecture to explore room temperature cavity quantum electrodynamics and to realize scalable multi-qubit computing. Here we review the present state of diamond photonic technology. The design, fabrication and characterization of a novel triangular cross section nanobeam cavity produced in a single crystal diamond is demonstrated. The present cavity design, based on a triangular cross section allows vertical confinement and better signal collection efficiency than that of slab-based nanocavities, and eliminates the need for a pre-existing membrane. The nanobeam is fabricated by Focused-Ion-Beam (FIB) patterning. The cavity is characterized by a confocal photoluminescence. The modes display quality factors of Q ~220 and are deviated in wavelength by only ~1.7nm from the NV- color center zero phonon line (ZPL). The measured results are found in good agreement with 3D Finite-Difference-Time-Domain (FDTD) calculations. A more advanced cavity design with Q=22,000 is model...

  13. 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.

  14. Bragg-case limited projection topography study of surface damage in diamond-crystal plates

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Y; Krasnicki, S; Macrander, A T; Chu, Y S; Maj, J [Advanced Photon Source, Argonne National Laboratory, Argonne (United States)

    2005-05-21

    To characterize diamond monochromators for synchrotron radiation beamlines, images for a region 25 {mu}m below the surface were obtained. Topographical images of a Bragg-diffracted beam having a scattering angle (twice the Bragg angle) of 90 deg. were obtained from asymmetric reflections with a CCD area detector. A 25 {mu}m incident slit was used to section the sample topographically. Patchwork images for the full surface area, but limited in depth to the slit size, were assembled from microbeam images. The small extinction depths provided by the asymmetric reflection geometry, namely, 2.8 {mu}m and 3.5 {mu}m for ideal diamond crystals set for the (224) and (044) reflections, respectively, permitted data analyses for a region near the surface. The diamonds were synthetic type Ib (yellowish due to nitrogen impurities). They were in the shape of plates sized 6 x 5 mm and were 0.5 mm thick. Measurements were made using monochromatic bending magnet radiation at the Advanced Photon Source at 12.04 keV and 13.90 keV. Data obtained before and after chemical etching demonstrate that damage visible as contrast from saw grooves is largely removed by etching. Dislocation etch pits were observed after etching for the (111) surface but not for the (100) surface.

  15. AFM Study on Interface of HTHP As-grown Diamond Single Crystal and Metallic Film

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The study for the interface of as-grown diamond and metallic film surrounding diamond is an attractive way for understanding diamond growth mechanism at high temperature and high pressure (HTHP), because it is that through the interface carbon atom groups from the molten film are transported to growing diamond surface. It is of great interest to perform atomic force microscopy (AFM) experiment, which provides a unique technique different from that of normal optical and electron microscopy studies, to observe the interface morphology. In the present paper,we report first that the morphologies obtained by AFM on the film are similar to those of corresponding diamond surface, and they are the remaining traces after the carbon groups moving from the film to growing diamond. The fine particles and a terrace structure with homogeneous average step height are respectively found on the diamond (100) and (111) surface. Diamond growth conditions show that its growth rates and the temperature gradients in the boundary layer of the molten film at HTHP result in the differences of surface morphologies on diamond planes,being rough on (100) plane and even on the (111) plane. The diamond growth on the (100) surface at HPHT could be considered as a process of unification of these diamond fine particles or of carbon atom groups recombination on the growing diamond crystal surface. Successive growth layer steps directly suggest the layer growth mechanism of the diamond (111) plane. The sources of the layer steps might be two-dimensional nuclei and dislocations.

  16. 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.

  17. The stability of a crystal with diamond structure for patchy particles with tetrahedral symmetry.

    Science.gov (United States)

    Noya, Eva G; Vega, Carlos; Doye, Jonathan P K; Louis, Ard A

    2010-06-21

    The phase diagram of model anisotropic particles with four attractive patches in a tetrahedral arrangement has been computed at two different values of the range of the potential, with the aim of investigating the conditions under which a diamond crystal can be formed. We find that the diamond phase is never stable for our longer-ranged potential. At low temperatures and pressures, the fluid freezes into a body-centered-cubic solid that can be viewed as two interpenetrating diamond lattices with a weak interaction between the two sublattices. Upon compression, an orientationally ordered face-centered-cubic crystal becomes more stable than the body-centered-cubic crystal, and at higher temperatures, a plastic face-centered-cubic phase is stabilized by the increased entropy due to orientational disorder. A similar phase diagram is found for the shorter-ranged potential, but at low temperatures and pressures, we also find a region over which the diamond phase is thermodynamically favored over the body-centered-cubic phase. The higher vibrational entropy of the diamond structure with respect to the body-centered-cubic solid explains why it is stable even though the enthalpy of the latter phase is lower. Some preliminary studies on the growth of the diamond structure starting from a crystal seed were performed. Even though the diamond phase is never thermodynamically stable for the longer-ranged model, direct coexistence simulations of the interface between the fluid and the body-centered-cubic crystal and between the fluid and the diamond crystal show that at sufficiently low pressures, it is quite probable that in both cases the solid grows into a diamond crystal, albeit involving some defects. These results highlight the importance of kinetic effects in the formation of diamond crystals in systems of patchy particles.

  18. Crystal Structure Refinement of Synthetic Pure Gyrolite

    Directory of Open Access Journals (Sweden)

    Arūnas Baltušnikas

    2015-03-01

    Full Text Available Pure calcium silicate hydrate – gyrolite was prepared under the saturated steam pressure at 473 K temperature in rotating autoclave. The crystal structure of synthetic gyrolite was investigated by X-ray diffraction and refined using Le Bail, Rietveld and crystal structure modelling methods. Background, peak shape parameters and verification of the space group were performed by the Le Bail full pattern decomposition. Peculiarities of interlayer sheet X of gyrolite unit cell were highlighted by Rietveld refinement. Possible atomic arrangement in interlayer sheet X was solved by global optimization method. Most likelihood crystal structure model of gyrolite was calculated by final Rietveld refinement. It was crystallographically showed, that cell parameters are: a = 0.9713(2 nm, b = 0.9715(2 nm, c = 2.2442(3 nm and alfa = 95.48(2 º, beta = 91.45(2 °, gamma = l20.05(3 °.DOI: http://dx.doi.org/10.5755/j01.ms.21.1.5460

  19. 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.

  20. 人造金刚石杂质研究%Research on the impurities in synthetic diamond

    Institute of Scientific and Technical Information of China (English)

    王裕昌

    2014-01-01

    利用磁化率测定仪、扫描电镜/X 射线能谱仪、氧氮分析仪等仪器综合分析了使用铁镍合金触媒合成的磨料级系列金刚石内部杂质及其组分与含量。结果表明:人造金刚石磁化率与灰分/金刚石质量比成正比。人造金刚石的主要杂质为铁、镍、镁、硅、钙、氧和氮。随着人造金刚石杂质总量的减少,除氮以外所有杂质都在减少,但杂质中的硅和钙的占比增加,提示硅和钙除了随同触媒一道,以金属包裹体的方式进入金刚石晶体,可能还有其他方式。金刚石品级越高,氧质量分数越低,而氮质量分数与品级高低无关。为进一步考察金刚石杂质来源,分析了合成金刚石试样所使用的原料石墨和触媒。使用高纯度石墨和触媒有助于合成出高纯度金刚石,但不一定是顶级金刚石。%The impurities in a series of abrasive diamonds synthesized by using iron and nickel alloy as catalyst,ranging from low grade to high grade,were investigated by employing magnetic susceptibility tester,SEM/EDS and oxygen nitrogen analyzer.The results show that magnetic susceptibility of synthetic diamond is proportional to the mass ratio of the diamond ash and the diamond itself.The main impurities in the synthetic diamond are iron, nickel, magnesium, silicon, calcium, oxygen and nitrogen.With the decrease of the total amount of impurities in the diamond,all of the impurities except for nitrogen decrease,but share of silicon and calcium increase.This fact implies that there may be another way for silicon and calcium get into the diamond lattice in addition to accompanying metal inclusions.The higher the diamond grade the lower the oxygen mass fraction,while the nitrogen mass fraction shows no relationship with diamond grade.To further investigate the origin of impurities in the diamond,the graphite and catalyst used for synthesizing the diamond were analyzed,too.Using of high

  1. Synthetic diamond devices for medical dosimetry applied to radiotherapy; Etude et developpement de dispositifs en diamant synthetique pour la dosimetrie medicale: applications en radiotherapie

    Energy Technology Data Exchange (ETDEWEB)

    Descamps, C

    2007-06-15

    The aim of this thesis, lead in the framework of an integrated European project entitled M.A.E.S.T.R.O. for ' Methods and Advanced Equipment for Simulation and Treatment in Radio Oncology', was to develop and test synthetic diamond detector in clinical environment for new modalities used in radiotherapy. Diamond is a good candidate for the detection of high energy beams in medical fields. It can be used for passive dosimetry, as thermoluminescent dosimeters or for active dosimetry as ionisation chambers. These two applications are presented here. Concerning the thermoluminescence, several impurities or dopants (boron, phosphorus, and nitrogen) have been incorporated in the diamond films during growth, in order to modify the material dosimetric properties and a detailed study of nitrogen-containing films is proposed. The second part presents the results obtained in active dosimetry. Two guide lines were followed: the measurement set-up optimisation and the material modification. The first dosimetric studies under radiotherapy beams concerning nitrogen-containing polycrystalline diamond as well as high purity single crystal diamond are conclusive. The detectors behaviours are in agreement with the recommendations of the International Atomic Energy Agency (IAEA). (author)

  2. 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

  3. Parabolic single-crystal diamond compound refractive lenses for coherent x-ray imaging (Conference Presentation)

    Science.gov (United States)

    Terentyev, Sergey; Blank, Vladimir D.; Polyakov, Sergey; Zholudev, Sergey; Snigirev, Anatoly A.; Polikarpov, Maxim; Kolodziej, Tomasz; Qian, Jun; Zhou, Hua; Shvyd'ko, Yuri V.

    2016-09-01

    We demonstrate parabolic single-crystal diamond compound refractive lenses [1] designed for coherent x-ray imaging resilient to extreme thermal and radiation loading expected from next generation light sources. To ensure the preservation of coherence and resilience, the lenses are manufactured from the highest-quality single-crystalline synthetic diamond material grown by a high-pressure high-temperature technique. Picosecond laser milling is applied to machine lenses to parabolic shapes with a 1-micron precision and surface roughness. A compound refractive lens comprised of six lenses with a radius of curvature R=200 microns at the vertex of the parabola and a geometrical aperture A=900 microns focuses 10 keV x-ray photons from an undulator source at the Advanced Photon Source facility to a focal spot size of 10x40 microns^2 with a gain factor of 100. [1] S. Terentyev, V. Blank, S. Polyakov, S. Zholudev, A. Snigirev, M. Polikarpov, T. Kolodziej, J. Qian, H. Zhou, and Yu. Shvyd'ko Applied Physics Letters 107, 111108 (2015); doi: 10.1063/1.4931357

  4. Fluid inclusions in carbonado diamond_Implication to the crystal growth environment

    Science.gov (United States)

    Kagi, H.; Ishibashi, H.; Sakurai, H.; Ohfuji, H.

    2010-12-01

    Diamond is a unique geological material carrying inside fluid and solid inclusions which are pristine witnesses of diamond crystallization media. Carbonado is natural polycrystalline diamond whose origin is still under hot depate. Our previous study on Central African carbonado reported the presence of fluid inclusions and high residual pressure in the diamond [1]. These results suggested that C-O-H mantle fluid was trapped in the carbonado sample and carbonado had grown in the volatile-rich environment in the mantle. However, it was unclear that the fluid inclusions in carbonado existed inside of diamond grains or in the grain boundaries. In this study, we precisely investigated the location of fluid inclusions from spectroscopic measurements and TEM observations. A carbonado grain with hundreds of micrometer in diameter was heated incrementally at temperatures from 700 to 1100°C under vacuum. After heating at each temperature condition, infrared absorption spectra were measured. Dehydration of hydrous minerals were observed with increasing temperature. In contrast, absorption bands assignable to liquid water were observed up to 950°C right before graphitization occurred. This observation strongly suggests that the fluid was trapped inside of diamond grains. For obtaining direct evidence of fluid inclusion existing inside of a diamond grain, we conducted TEM observations on an FIB-fabricated thin foil of carbonado. We found a void in the carbonado sample. The void was surrounded by (111) equivalent crystal faces. The octahedral void controlled by crystal habit of host diamond strongly suggests that the void is the negative crystal of diamond. The existence of negative crystal of diamond indicates that the fluid equilibrated with surrounding diamond crystals. Moreover, it was found that the grain boundary of the polished carbonado sample was in zig-zag texture. The detailed EBSD analyses on the grain boundary indicated that the grain boundary corresponded to the

  5. Adhesion and friction of single-crystal diamond in contact with transition metals

    Science.gov (United States)

    Miyoshi, K.; Buckley, D. H.

    1980-01-01

    An investigation was conducted to examine the adhesion and friction of single-crystal diamond in contact with various transition metals and the nature of metal transfer to diamond. Sliding friction experiments were conducted with diamond in sliding contact with the metals yttrium, titanium, zirconium, vanadium, iron, cobalt, nickel, tungsten, platinum, rhenium and rhodium. All experiments were conducted with loads of 0.05 to 0.3 N, at a sliding velocity of 0.003 m per minute, in a vacuum of 10 to the -8th Pa, at room temperature, and on the (111) plane of diamond with sliding in the 110 line type direction. The results of the investigation indicate that the coefficient of friction for diamond in contact with various metals is related to the relative chemical activity of the metals in high vacuum. The more active the metal, the higher the coefficient of friction. All the metals examined transferred to the surface of diamond in sliding.

  6. Performance of a beam-multiplexing diamond crystal monochromator at the Linac Coherent Light Source

    OpenAIRE

    Zhu, Diling; Feng, Yiping; Stoupin, Stanislav; Terentyev, Sergey A.; Lemke, Henrik T.; Fritz, David M.; Chollet, Matthieu; Glownia, J. M.; Alonso-Mori, Roberto; Sikorski, Marcin; Song, Sanghoon; Brandt van Driel, Tim; Williams, Garth J; Messerschmidt, Marc; Boutet, Sébastien

    2014-01-01

    A double-crystal diamond monochromator was recently implemented at the Linac Coherent Light Source. It enables splitting pulses generated by the free electron laser in the hard x-ray regime and thus allows the simultaneous operations of two instruments. Both monochromator crystals are High-Pressure High-Temperature grown type-IIa diamond crystal plates with the (111) orientation. The first crystal has a thickness of ∼100 μm to allow high reflectivity within the Bragg bandwidth and good transm...

  7. EBS/C proton spectra from a virgin diamond crystal

    Energy Technology Data Exchange (ETDEWEB)

    Erich, M., E-mail: marko.erich@gmail.com [Laboratory of Physics, Vinča Institute of Nuclear Sciences, University of Belgrade, PO Box 552, Belgrade (Serbia); Kokkoris, M. [Department of Physics, National Technical University of Athens, Zografou Campus 157 80, Athens (Greece); Fazinić, S. [Laboratory for Ion Beam Interactions, Department of Experimental Physics, Institute Ruđer Bošković, Bijenička cesta 54, 10000 Zagreb (Croatia); Petrović, S. [Laboratory of Physics, Vinča Institute of Nuclear Sciences, University of Belgrade, PO Box 552, Belgrade (Serbia)

    2016-08-15

    In the present work, elastic backscattering channeling spectra, EBS/C, of protons in a 〈1 0 0〉 diamond crystal were experimentally and theoretically studied via a new computer simulation code. Proton incident energies for EBS/C spectra were in the energy range from 1.0 MeV to 1.9 MeV. The energy range was chosen in order to explore a distinct strong resonance of the {sup 12}C(p,p{sub 0}){sup 12}C elastic scattering at 1737 keV. The computer simulation code applied for the fitting of the experimental spectra in the random mode was compared with the corresponding SIMNRA results. In the channeling mode, it assumes a Gompertz type sigmoidal dechanneling function, which has two fitting parameters, x{sub c} and k, the dechanneling range and rate, respectively. It also uses α, ratio of the channeling to random energy losses, as a fitting parameter. It was observed that x{sub c} increases, k decreases and α stays relatively constant with the proton incident energy. These observations confirm the physical interpretation of the fitting parameters. Also, they constitute the basics for the further development of the code for the quantification of induced amorphization and depth profiling of implanted ions.

  8. EBS/C proton spectra from a virgin diamond crystal

    Science.gov (United States)

    Erich, M.; Kokkoris, M.; Fazinić, S.; Petrović, S.

    2016-08-01

    In the present work, elastic backscattering channeling spectra, EBS/C, of protons in a diamond crystal were experimentally and theoretically studied via a new computer simulation code. Proton incident energies for EBS/C spectra were in the energy range from 1.0 MeV to 1.9 MeV. The energy range was chosen in order to explore a distinct strong resonance of the 12C(p,p0)12C elastic scattering at 1737 keV. The computer simulation code applied for the fitting of the experimental spectra in the random mode was compared with the corresponding SIMNRA results. In the channeling mode, it assumes a Gompertz type sigmoidal dechanneling function, which has two fitting parameters, xc and k, the dechanneling range and rate, respectively. It also uses α, ratio of the channeling to random energy losses, as a fitting parameter. It was observed that xc increases, k decreases and α stays relatively constant with the proton incident energy. These observations confirm the physical interpretation of the fitting parameters. Also, they constitute the basics for the further development of the code for the quantification of induced amorphization and depth profiling of implanted ions.

  9. Diamond single crystal-surface modification under high- fluence ion irradiation

    Science.gov (United States)

    Anikin, V. A.; Borisov, A. M.; Kazakov, V. A.; Mashkova, E. S.; Palyanov, Yu N.; Popov, V. P.; Shmytkova, E. A.; Sigalaev, S. K.

    2016-09-01

    The modification of (111) face of synthetic diamond has been studied experimentally for high-fluence 30 keV argon bombardment. It has been found that ion irradiation leads to the electrically conductive layer formation the sheet resistance of which decreases more than 100 times while changing the temperature of the irradiated diamond from 70 to 400 oC. This effect, as well as significant changes of optical transmittance after ion irradiation are associated with ion-induced structural changes of irradiated diamond obtained by the methods of Raman spectroscopy.

  10. 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.

  11. Radial mosaic internal structure of rounded diamond crystals from alluvial placers of Siberian platform

    Science.gov (United States)

    Ragozin, A. L.; Zedgenizov, D. A.; Kuper, K. E.; Shatsky, V. S.

    2016-12-01

    The specific gray to almost black diamonds of rounded morphology are especially typical in alluvial placers of the northeastern part of the Siberian platform. The results of study of internal structure of these diamonds are presented. X-ray topography and birefringence patterns of polished plates of studied diamonds show their radial mosaic structure. Diamonds consists of slightly misorientated (up to 20') subindividuals which are combined to mosaic wedge-shaped sectors. Electron back-scatter diffraction technique has demonstrated that subindividuals are often combined in the single large blocks (subgrains). The whole crystals commonly consist of several large subgrains misoriented up to 5° to one another. The total nitrogen content of these diamonds vary in the range 900-3300 ppm and nitrogen aggregation state (NB/(NB + NA)*100) from 25 to 64 %. Rounded diamond crystals of variety V are suggested to have been formed at the high growth rate caused by the high oversaturation of carbon in the crystallization medium. It may result in the splitting of growing crystal and their radial mosaic structure as a sequence. High content of structural nitrogen defects and the great number of mechanical impurities - various mineral and fluid inclusions may also favor to generation of this structure.

  12. Invited Article: Precision nanoimplantation of nitrogen vacancy centers into diamond photonic crystal cavities and waveguides

    Science.gov (United States)

    Schukraft, M.; Zheng, J.; Schröder, T.; Mouradian, S. L.; Walsh, M.; Trusheim, M. E.; Bakhru, H.; Englund, D. R.

    2016-05-01

    We demonstrate a self-aligned lithographic technique for precision generation of nitrogen vacancy (NV) centers within photonic nanostructures on bulk diamond substrates. The process relies on a lithographic mask with nanoscale implantation apertures for NV creation, together with larger features for producing waveguides and photonic nanocavities. This mask allows targeted nitrogen ion implantation, and precision dry etching of nanostructures on bulk diamond. We demonstrate high-yield generation of single NVs at pre-determined nanoscale target regions on suspended diamond waveguides. We report implantation into the mode maximum of diamond photonic crystal nanocavities with a single-NV per cavity yield of ˜26% and Purcell induced intensity enhancement of the zero-phonon line. The generation of NV centers aligned with diamond photonic structures marks an important tool for scalable production of optically coupled spin memories.

  13. Growth of Large High-Quality Type-Ⅱ a Diamond Crystals

    Institute of Scientific and Technical Information of China (English)

    WANG Xian-Cheng; MA Hong-An; ZANG Chuan-Yi; TIAN Yu; LI Shang-Sheng; JIA Xiao-Peng

    2005-01-01

    @@ Large high-quality type-Ⅱ a diamond crystals in size of about 4.0mm have been grown under the condition of 5.5 GPa and 1200-1300 ℃ by using the temperature gradient method in a domestic cubic anvil high-pressure apparatus. The Fe55Co16Ni25 alloy (KOV) is used as the solvent metal, and Ti with the content 1.5wt.% of the solvent metal is selected as the nitrogen getter to reduce the impurity of nitrogen in the diamond crystal.To avoid the impurities and cave in the crystal, the growth rate of the initial stage of the growing process is controlled within 0.45mg/h and the ring carbon source of the size φ8mm-φ6mm×3 mm is used to gnow large diamond crystals.

  14. Numerical Modeling on Thermal Loading of Diamond Crystal in X-ray FEL Oscillator

    CERN Document Server

    Song, Meiqi; Guo, Yuhang; Li, Kai; Deng, Haixiao

    2015-01-01

    Due to high reflectivity and high resolution to X-ray pulse, diamond is one of the most popular Bragg crystals serving as the reflecting mirror and mono-chromator in the next generation free electrons lasers (FELs). The energy deposition of X-rays will result in thermal heating, and thus lattice expanding of diamond crystal, which may degrade the performance of X-ray FELs. In this paper, the thermal loading effect of diamond crystal for X-ray FEL oscillator has been systematically studied by the combined simulation of Geant4 and ANSYS, and its dependence on the environment temperature, crystal size, X-ray pulse repetition rate and pulse energy are presented.

  15. Performance of a beam-multiplexing diamond crystal monochromator at the Linac Coherent Light Source

    DEFF Research Database (Denmark)

    Zhu, Diling; Feng, Yiping; Stoupin, Stanislav

    2014-01-01

    A double-crystal diamond monochromator was recently implemented at the Linac Coherent Light Source. It enables splitting pulses generated by the free electron laser in the hard x-ray regime and thus allows the simultaneous operations of two instruments. Both monochromator crystals are High-Pressu...

  16. Laser-assisted synthesis of diamond crystals in open air through vibrational excitation of precursor molecules

    Science.gov (United States)

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

    2011-03-01

    Fast growth of diamond crystals in open air was achieved by laser-assisted combustion synthesis through vibrational excitation of precursor molecules. A wavelength-tunable CO2 laser (spectrum range from 9.2 to 10.9 μm) was used for the vibrational excitation in synthesis of diamond crystals. A pre-mixed C2H4/C2H2/O2 gas mixture was used as precursors. Through resonant excitation of the CH2-wagging mode of ethylene (C2H4) molecules using the CO2 laser tuned at 10.532 Μm, high-quality diamond crystals were grown on silicon substrates with a high growth rate of ~139 μm/hr. Diamond crystals with a length up to 5 mm and a diameter of 1 mm were grown in 36 hours. Sharp Raman peaks at 1332 cm-1 with full width at half maximum (FWHM) values around 4.5 cm-1 and distinct X-ray diffraction spectra demonstrated the high quality of the diamond crystals. The effects of the resonant excitation of precursor molecules by the CO2 laser were investigated using optical emission spectroscopy.

  17. Investigation of focused ion beam induced damage in single crystal diamond tools

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Zhen [Centre for Precision Manufacturing, Department of Design, Manufacture & Engineering Management, University of Strathclyde, Glasgow G1 1XQ (United Kingdom); Center for Precision Engineering, Harbin Institute of Technology, Harbin 150001 (China); Luo, Xichun, E-mail: Xichun.Luo@strath.ac.uk [Centre for Precision Manufacturing, Department of Design, Manufacture & Engineering Management, University of Strathclyde, Glasgow G1 1XQ (United Kingdom)

    2015-08-30

    Highlights: • The FIB-induced damage layer should be paid enough attention when shaping the cutting edges of nanoscale diamond tools. • During FIB processing cutting tools made of natural single crystal diamond, the Ga{sup +} collision will create a damage layer around tool tips. • The thicknesses of damaged layer and the level for amorphization of diamond significantly increase with beam energy. • The FIB-induced doping and defects during tool fabrication are responsible for the early detection of tool wear of nanoscale diamond tools. - Abstract: In this work, transmission electron microscope (TEM) measurements and molecular dynamics (MD) simulations were carried out to characterise the focused ion beam (FIB) induced damage layer in a single crystal diamond tool under different FIB processing voltages. The results obtained from the experiments and the simulations are in good agreement. The results indicate that during FIB processing cutting tools made of natural single crystal diamond, the energetic Ga{sup +} collision will create an impulse-dependent damage layer at the irradiated surface. For the tested beam voltages in a typical FIB system (from 8 kV to 30 kV), the thicknesses of the damaged layers formed on a diamond tool surface increased from 11.5 nm to 27.6 nm. The dynamic damage process of FIB irradiation and ion–solid interactions physics leading to processing defects in FIB milling were emulated by MD simulations. The research findings from this study provide the in-depth understanding of the wear of nanoscale multi-tip diamond tools considering the FIB irradiation induced doping and defects during the tool fabrication process.

  18. Focusing characteristics of diamond crystal x-ray monochromators. An experimental and theoretical comparison

    DEFF Research Database (Denmark)

    Rio, M.S. del; Grübel, G.; Als-Nielsen, J.

    1995-01-01

    Perfect crystals in transmission (Laue) geometry can be used effectively for x-ray monochromators, and moreover, perfect Laue crystals show an interesting focusing effect when the incident beam is white and divergent. This focusing is directly dependent on the incident beam divergence and on the ...... from a diamond crystal in Lane geometry, and we analyze and explain the results by comparison with ray-tracing simulations. (C) 1995 American Institute of Physics....

  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. On Room-Temperature Inversion of EPR Signals of P1 Centre in Synthetic Diamond

    Institute of Scientific and Technical Information of China (English)

    G. G. Fedoruk; O. N. Poklonskaya

    2009-01-01

    Room-temperature inversion of EPR absorption signals of P1 centre in synthetic diamond is studied by the tran-sient nutation technique. Use of the bichromatic field, consisting of a transverse microwave field and longitudinal radio frequency field, allows to investigate the dynamics of P1 centres in the same field configuration as in cw EPR spectrometers. It is shown that the annealing decreases the P1 centre concentration and, respectively, increases the spin-spin relaxation time. As a result, the periodic inversion (nutation) of the P1 centre absorption signal is observed longer. It is assumed that the P1 centre signal inversion, which was previously observed by cw EPR, might be caused by the Bloch-Siegert effect in the biehromatic field.

  1. Opal-like photonic crystal with diamond lattice

    CERN Document Server

    Garcia Santamaria, F; López, C; Meseguer, F; Miyazaki, H T; Sánchez-Dehesa, J

    2002-01-01

    In this contribution, a method to fabricate a diamond structure with a complete PBG in the near infrared is proposed. The procedure starts by building an opal composed of two types of microspheres (organic and inorganic) in a body-centered-cubic symmetry by means of a micro- robotic technique. Then, the organic particles may be selectively removed to obtain a diamond structure of inorganic particles. Once this structure is assembled its filling fraction may be controlled by sintering. Subsequently this template can be infiltrated with an adequate high refractive index material. In this way, the method can be extended to make diamond inverse opals of, for instance, silicon with gap to mid gap ratios as large as 13% for moderate filling fractions. An overview of micromanipulation as well as previous experimental results will be offered to show the feasibility of this method. (24 refs).

  2. A photoemission study of the diamond and the single crystal C{sub 60}

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jin

    1994-03-01

    This report studied the elctronic structure of diamond (100) and diamond/metal interface and C{sub 60}, using angle-resolved and core level photoemission. The C(100)-(2X1) surface electronic structure was studied using both core level and angle resolved valence band photoemission spectroscopy. The surface component of the C 1s core level spectrum agrees with theoretical existence of only symmetrical dimers. In the case of metal/diamond interfaces, core level and valence photoelectron spectroscopy and LEED studies WERE MADE OF B and Sb on diamond (100) and (111) surfaces. In the case of single-crystal C{sub 60}, photoemission spectra show sharp molecular features, indicating that the molecular orbitals are relatively undisturbed in solid C{sub 60}.

  3. Structure analysis on synthetic emerald crystals

    Science.gov (United States)

    Lee, Pei-Lun; Lee, Jiann-Shing; Huang, Eugene; Liao, Ju-Hsiou

    2013-05-01

    Single crystals of emerald synthesized by means of the flux method were adopted for crystallographic analyses. Emerald crystals with a wide range of Cr3+-doping content up to 3.16 wt% Cr2O3 were examined by X-ray single crystal diffraction refinement method. The crystal structures of the emerald crystals were refined to R 1 (all data) of 0.019-0.024 and w R 2 (all data) of 0.061-0.073. When Cr3+ substitutes for Al3+, the main adjustment takes place in the Al-octahedron and Be-tetrahedron. The effect of substitution of Cr3+ for Al3+ in the beryl structure results in progressively lengthening of the Al-O distance, while the length of the other bonds remains nearly unchanged. The substitution of Cr3+ for Al3+ may have caused the expansion of a axis, while keeping the c axis unchanged in the emerald lattice. As a consequence, the Al-O-Si and Al-O-Be bonding angles are found to decrease, while the angle of Si-O-Be increases as the Al-O distance increases during the Cr replacement.

  4. Free-standing nanomechanical and nanophotonic structures in single-crystal diamond

    Science.gov (United States)

    Burek, Michael John

    Realizing complex three-dimensional structures in a range of material systems is critical to a variety of emerging nanotechnologies. This is particularly true of nanomechanical and nanophotonic systems, both relying on free-standing small-scale components. In the case of nanomechanics, necessary mechanical degrees of freedom require physically isolated structures, such as suspended beams, cantilevers, and membranes. For nanophotonics, elements like waveguides and photonic crystal cavities rely on light confinement provided by total internal reflection or distributed Bragg reflection, both of which require refractive index contrast between the device and surrounding medium (often air). Such suspended nanostructures are typically fabricated in a heterolayer structure, comprising of device (top) and sacrificial (middle) layers supported by a substrate (bottom), using standard surface nanomachining techniques. A selective, isotropic etch is then used to remove the sacrificial layer, resulting in free-standing devices. While high-quality, crystalline, thin film heterolayer structures are readily available for silicon (as silicon-on-insulator (SOI)) or III-V semiconductors (i.e. GaAs/AlGaAs), there remains an extensive list of materials with attractive electro-optic, piezoelectric, quantum optical, and other properties for which high quality single-crystal thin film heterolayer structures are not available. These include complex metal oxides like lithium niobate (LiNbO3), silicon-based compounds such as silicon carbide (SiC), III-V nitrides including gallium nitride (GaN), and inert single-crystals such as diamond. Diamond is especially attractive for a variety of nanoscale technologies due to its exceptional physical and chemical properties, including high mechanical hardness, stiffness, and thermal conductivity. Optically, it is transparent over a wide wavelength range (from 220 nm to the far infrared), has a high refractive index (n ~ 2.4), and is host to a vast

  5. Entrapment of Inclusions in Diamond Crystals Grown from Fe-Ni-C System

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Diamond single crystals grown from Fe-Ni-C system at high temperature-high pressure (HPHT) usually contain inclusions related to the metallic catalyst. During the diamond growth, the metallic inclusions are trapped by the growth front or are formed through reaction between the contaminants trapped in the diamond. In the present paper, the metallic inclusions related to the catalyst were systematically examined by transmission electron microscopy (TEM). The chemical composition and crystal structure of the metallic inclusions were for the first time determined by selected area electron diffraction pattern (SADP) combined with energy dispersive X-ray spectrometry (EDS). It is shown that the inclusions are mainly composed of orthorhombic FeSi2, fcc (FeNi)23C6, and orthorhombic Fe3C,hexagonal Ni3C.

  6. Hemispherical Brillouin zone imaging of a diamond-type biological photonic crystal

    NARCIS (Netherlands)

    Wilts, Bodo D.; Michielsen, Kristel; De Raedt, Hans; Stavenga, Doekele G.

    2012-01-01

    The brilliant structural body colours of many animals are created by three-dimensional biological photonic crystals that act as wavelength-specific reflectors. Here, we report a study on the vividly coloured scales of the diamond weevil, Entimus imperialis. Electron microscopy identified the chitin

  7. Hemispherical Brillouin zone imaging of a diamond-type biological photonic crystal

    NARCIS (Netherlands)

    Wilts, Bodo D.; Michielsen, Kristel; De Raedt, Hans; Stavenga, Doekele G.

    2012-01-01

    The brilliant structural body colours of many animals are created by three-dimensional biological photonic crystals that act as wavelength-specific reflectors. Here, we report a study on the vividly coloured scales of the diamond weevil, Entimus imperialis. Electron microscopy identified the chitin

  8. Fabrication of Triangular Nanobeam Waveguide Networks in Bulk diamond Using Single-Crystal Silicon Hard Masks

    CERN Document Server

    Bayn, I; Li, L; Goldstein, J A; Schröder, T; Zhang, J; Chen, E H; Gaathon, O; Lu, M; Stein, A; Ruggiero, C A; Salzman, J; Kalish, R; Englund, D

    2014-01-01

    A scalable approach for integrated photonic networks in single-crystal diamond using triangular etching of bulk samples is presented. We describe designs of high quality factor (Q=2.51x10^6) photonic crystal cavities with low mode volume (Vm=1.062x({\\lambda}/n)^3), which are connected via waveguides supported by suspension structures with predicted transmission loss of only 0.05 dB. We demonstrate the fabrication of these structures using transferred single-crystal silicon hard masks and angular dry etching, yielding photonic crystal cavities in the visible spectrum with measured quality factors in excess of Q=3x103.

  9. Fabrication of Terahertz Wave Resonators with Alumina Diamond Photonic Crystals for Frequency Amplification in Water Solvents

    Energy Technology Data Exchange (ETDEWEB)

    Ohta, N; Niki, T; Kirihara, S, E-mail: n-ohta@jwri.osaka-u.ac.jp [Smart Processing Research Center, Joining and Welding Research Institute, Osaka University, Ibaraki, Osaka, 567-0047 (Japan)

    2011-05-15

    Terahertz wave resonators composed of alumina photonic crystals with diamond lattice structures were designed and fabricated by using micro stereolithography. These three dimensional periodic structures can reflect perfectly electromagnetic waves through Bragg diffraction. A micro glass cell including water solutions was put between the photonic crystals as a novel resonance sensor with terahertz frequency range. The localized and amplified waves in the resonators were measured by a spectroscopy, and visualized by theoretical simulations.

  10. Scalable Fabrication of Integrated Nanophotonic Circuits on Arrays of Thin Single Crystal Diamond Membrane Windows.

    Science.gov (United States)

    Piracha, Afaq H; Rath, Patrik; Ganesan, Kumaravelu; Kühn, Stefan; Pernice, Wolfram H P; Prawer, Steven

    2016-05-11

    Diamond has emerged as a promising platform for nanophotonic, optical, and quantum technologies. High-quality, single crystalline substrates of acceptable size are a prerequisite to meet the demanding requirements on low-level impurities and low absorption loss when targeting large photonic circuits. Here, we describe a scalable fabrication method for single crystal diamond membrane windows that achieves three major goals with one fabrication method: providing high quality diamond, as confirmed by Raman spectroscopy; achieving homogeneously thin membranes, enabled by ion implantation; and providing compatibility with established planar fabrication via lithography and vertical etching. On such suspended diamond membranes we demonstrate a suite of photonic components as building blocks for nanophotonic circuits. Monolithic grating couplers are used to efficiently couple light between photonic circuits and optical fibers. In waveguide coupled optical ring resonators, we find loaded quality factors up to 66 000 at a wavelength of 1560 nm, corresponding to propagation loss below 7.2 dB/cm. Our approach holds promise for the scalable implementation of future diamond quantum photonic technologies and all-diamond photonic metrology tools.

  11. Effects of catalyst height on diamond crystal morphology under high pressure and high temperature

    Science.gov (United States)

    Ya-Dong, Li; Xiao-Peng, Jia; Bing-Min, Yan; Ning, Chen; Chao, Fang; Yong, Li; Hong-An, Ma

    2016-04-01

    The effect of the catalyst height on the morphology of diamond crystal is investigated by means of temperature gradient growth (TGG) under high pressure and high temperature (HPHT) conditions with using a Ni-based catalyst in this article. The experimental results show that the morphology of diamond changes from an octahedral shape to a cub-octahedral shape as the catalyst height rises. Moreover, the finite element method (FEM) is used to simulate the temperature field of the melted catalyst/solvent. The results show that the temperature at the location of the seed diamond continues to decrease with the increase of catalyst height, which is conducive to changing the morphology of diamond. This work provides a new way to change the diamond crystal morphology. Project supported by the National Natural Science Foundation of China (Grant No. 51172089), the Program for New Century Excellent Talents in University, the Natural Science Foundation of Guizhou Provincial Education Department (Grant No. KY[2013]183), and the Collaborative Fund of Science and Technology Office of Guizhou Province, China (Grant No. LH[2015]7232).

  12. Dosimetry of cone-defined stereotactic radiosurgery fields with a commercial synthetic diamond detector

    Energy Technology Data Exchange (ETDEWEB)

    Morales, Johnny E., E-mail: johnny.morales@lh.org.au [Department of Radiation Oncology, Chris O’Brien Lifehouse, 119-143 Missenden Road, Camperdown, NSW 2050, Australia and School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Level 4 O Block, Garden’s Point, Brisbane, QLD 4001 (Australia); Crowe, Scott B.; Trapp, J. V. [School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Level 4 O Block, Garden’s Point, Brisbane, QLD 4001 (Australia); Hill, Robin [Department of Radiation Oncology, Chris O’Brien Lifehouse, 119-143 Missenden Road, Camperdown, NSW 2050 (Australia); Freeman, Nigel [Department of Radiation Oncology, St Vincent’s Hospital, Victoria Street, Darlinghurst, NSW 2010 (Australia)

    2014-11-01

    Purpose: Small field x-ray beam dosimetry is difficult due to lack of lateral electronic equilibrium, source occlusion, high dose gradients, and detector volume averaging. Currently, there is no single definitive detector recommended for small field dosimetry. The objective of this work was to evaluate the performance of a new commercial synthetic diamond detector, namely, the PTW 60019 microDiamond, for the dosimetry of small x-ray fields as used in stereotactic radiosurgery (SRS). Methods: Small field sizes were defined by BrainLAB circular cones (4–30 mm diameter) on a Novalis Trilogy linear accelerator and using the 6 MV SRS x-ray beam mode for all measurements. Percentage depth doses (PDDs) were measured and compared to an IBA SFD and a PTW 60012 E diode. Cross profiles were measured and compared to an IBA SFD diode. Field factors, Ω{sub Q{sub c{sub l{sub i{sub n,Q{sub m{sub s{sub r}{sup f{sub c}{sub l}{sub i}{sub n},f{sub m}{sub s}{sub r}}}}}}}}}, were calculated by Monte Carlo methods using BEAMnrc and correction factors, k{sub Q{sub c{sub l{sub i{sub n,Q{sub m{sub s{sub r}{sup f{sub c}{sub l}{sub i}{sub n},f{sub m}{sub s}{sub r}}}}}}}}}, were derived for the PTW 60019 microDiamond detector. Results: For the small fields of 4–30 mm diameter, there were dose differences in the PDDs of up to 1.5% when compared to an IBA SFD and PTW 60012 E diode detector. For the cross profile measurements the penumbra values varied, depending upon the orientation of the detector. The field factors, Ω{sub Q{sub c{sub l{sub i{sub n,Q{sub m{sub s{sub r}{sup f{sub c}{sub l}{sub i}{sub n},f{sub m}{sub s}{sub r}}}}}}}}}, were calculated for these field diameters at a depth of 1.4 cm in water and they were within 2.7% of published values for a similar linear accelerator. The corrections factors, k{sub Q{sub c{sub l{sub i{sub n,Q{sub m{sub s{sub r}{sup f{sub c}{sub l}{sub i}{sub n},f{sub m}{sub s}{sub r}}}}}}}}}, were derived for the PTW 60019 microDiamond detector. Conclusions

  13. Charge collection uniformity and irradiation effects of synthetic diamond detectors studied with a proton micro-beam

    Science.gov (United States)

    Cazzaniga, C.; Rebai, M.; Garcia Lopez, J.; Jimenez-Ramos, M. C.; Girolami, M.; Trucchi, D. M.; Bellucci, A.; Frost, C. D.; Garcia-Munoz, M.; Nocente, M.; Tardocchi, M.; Gorini, G.

    2017-08-01

    The proton micro-beam of the CNA accelerator in Seville has been used to test two detectors based on single crystal diamond grown by chemical vapor deposition. The first diamond has a more traditional design, with dimensions 4.5 × 4.5 × 0.5 mm3, and features a large contact of the same size as the crystal. The second, with dimensions 2.0 × 2.0 × 0.3 mm3, features a small contact of 0.5 × 0.5 mm2. By using the micro-beam, the map of the charge collection efficiency for both the detectors have been measured. We show that the charge collection efficiency of the diamond with large contacts is generally uniform, while the diamond with smaller contacts needs further developments in this respect. A proof of principle test with a fast electronic chain has been performed to demonstrate that spatially resolved pulse shape analysis can be performed with this system. The micro-beam allowed also studying radiation-induced permanent damage and polarization, which are two irradiation effects of importance for the development of diamonds used in spectroscopy applications.

  14. Raman scattering in heavily boron-doped single-crystal diamond

    Directory of Open Access Journals (Sweden)

    G. Faggio

    2011-09-01

    Full Text Available A series of boron-doped homoepitaxial diamond films grown by Microwave Plasma Enhanced Chemical Vapor Deposition at the University of Rome "Tor Vergata" have been investigated with Raman spectroscopy. As the boron content increases, we observed systematic modifications in the Raman spectra of single-crystal diamonds. A significant change in the lineshape of the first-order Raman peak as well as a wide and structured signal at lower wavenumbers appeared simultaneously in samples grown at higher boron content.

  15. SURFACE ROUGHNESS PREDICTION MODEL FOR ULTRAPRECISION TURNING ALUMINIUM ALLOYWITH A SINGLE CRYSTAL DIAMOND TOOL

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A surface roughness model utilizing regression analysis method is developed for predicting roughness of ultraprecision machined surface with a single crystal diamond tool. The effects of the main variables,such as cutting speed,feed,and depth of cut on surface roughness are also analyzed in diamond turning aluminum alloy. In order to predict and control the surface roughness before ultraprecision machining,constrained variable metric method is used to select the optimum cutting conditions during process planning. A lot of experimental results show that the model can predict the surface roughness effectively under a certain cutting conditions .

  16. Iron oxidation state in (Mg,Fe)O: Calibration of the flank method on synthetic samples and application to natural inclusions in Lower Mantle diamonds

    Science.gov (United States)

    Longo, M.; McCammon, C.; Bulanova, G.; Kaminsky, F.

    2008-12-01

    Ferropericlase (Mg,Fe)O and (Mg,Fe)(Si,Al)O3 perovskite are believed to form the bulk of the Lower Mantle (LM). The interval of redox conditions in the LM is still debatable. It was shown that the Fe3+ concentration in perovskite is insensitive to oxygen fugacity, therefore we have turned our attention to (Mg,Fe)O. Our work involves calibrating the so-called "flank method" for synthetic (Mg,Fe)O, and applying the results to determine Fe3+/Fetot in ferropericlase inclusions from LM diamonds, as a direct tool for investigating LM redox conditions during diamond formation. Experiments were performed in a multi anvil apparatus to obtain ferropericlase crystals with high quality surfaces, and Fe3+/Fetot in them was determined by Moessbauer spectroscopy. Samples were subsequently analyzed using the EMP. The flank method sensu strictu consists of measuring two pre-defined energy positions FeLAlfa and FeLBeta, whose ratio is sensitive to Fe2+/Fe3+. Positive correlations of LBeta/LAlfa as a function of Fetot (wt percent) and Fe2+ (wt percent) were observed for (Mg,Fe)O similar to those reported in the literature for garnets. We applied a least-squares regression model to fit the three variables Fetot, LBeta/LAlfa and Fe2+, and chose the simplest equation that fit the data. Our calibration for (Mg,Fe)O with xFe between 2 and 36.6 wt percent shows an agreement of 1 sigma with Fe3+/Fetot determined by Moessbauer spectroscopy, but with the additional advantage of a spatial resolution on the order of 10 microns (compared to no smaller than 100 microns for Moessbauer). We applied the flank method calibration to 6 ferropericlase inclusions from ultra deep diamonds (4 from Mato Grosso and 2 from Machado River, Brazil). Results show that LBeta/LAlfa ratios are consistent with the trend observed for synthetic (Mg,Fe)O, with no obvious evidence for magnesioferrite exsolution. The obtained Fe3+/Fetot values between 8 and 13 percent, and their correlations with Na, Cr and Al show that

  17. RESEARCH OF PROCESSES ON FORMATION AND TRIBOTECHNICAL PROPERTIES OF WEAR-RESISTANT COMPOSITE GAS THERMAL COATINGS BEING DISPERSIVELY STRENGTHENED BY SYNTHETIC DIAMONDS AND ELECTRO-CORUNDUM

    Directory of Open Access Journals (Sweden)

    O. S. Kobjakov

    2011-01-01

    Full Text Available Formation processes, tribotechnical and wear-resistant properties of composite gas thermal coatings being dispersively strengthened by synthetic diamonds and electro-corundum are investigated in the paper.

  18. 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)

  19. 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.

  20. Magnetic phase of the Fe-containing inclusions in synthetic diamond grits

    DEFF Research Database (Denmark)

    Bharuth-Ram, K.; Hansen, Mikkel Fougt

    2002-01-01

    temperature. Hysteresis was observed in the static field dependence of the magnetization, with coercive fields H-c of 40 and 70 Oe for the inclusions in the 63-75 and 30-18 mum grits; respectively. Within the temperature range of our measurements (10-300 K) the normalized magnetization curves did not scale...... of the inclusions play an important role in the durability of the grits.In order to obtain information on the size and composition Of the inclusions in MDAS(R) (1) synthetic diamond grits We have performed magnetization measurements as Well as elemental analysis of the inclusions in MDAS grits of US mesh 400......-500 (mean size, d=30-18 mum) and mesh 200-230 (d=63-75 mum) Temperature and field-dependent magnetization measurements Were made with a SQUID magnetometer. The ZFC/FC behaviour of both sets of grits supported the conclusion that the Curie temperature of the Fe-containing inclusions was above room...

  1. Numerical modeling of thermal loading of diamond crystal in X-ray FEL oscillators

    Science.gov (United States)

    Song, Mei-Qi; Zhang, Qing-Min; Guo, Yu-Hang; Li, Kai; Deng, Hai-Xiao

    2016-04-01

    Due to high reflectivity and high resolution of X-ray pulses, diamond is one of the most popular Bragg crystals serving as the reflecting mirror and mono-chromator in the next generation of free electron lasers (FELs). The energy deposition of X-rays will result in thermal heating, and thus lattice expansion of the diamond crystal, which may degrade the performance of X-ray FELs. In this paper, the thermal loading effect of diamond crystal for X-ray FEL oscillators has been systematically studied by combined simulation with Geant4 and ANSYS, and its dependence on the environmental temperature, crystal size, X-ray pulse repetition rate and pulse energy are presented. Our results show that taking the thermal loading effects into account, X-ray FEL oscillators are still robust and promising with an optimized design. Supported by National Natural Science Foundation of China (11175240, 11205234, 11322550) and Program for Changjiang Scholars and Innovative Research Team in University (IRT1280)

  2. Crystallization by Particle Attachment in Synthetic, Biogenic, and Geologic Environments

    Energy Technology Data Exchange (ETDEWEB)

    De Yoreo, James J.; Gilbert, Pupa U.; Sommerdijk, Nico; Penn, R. Lee; Whitelam, Stephen B.; Joester, Derk; Zhang, Hengzhong; Rimer, Jeffrey D.; Navrotsky, Alexandra; Banfield, Jillian F.; Wallace, Adam F.; Michel, F. M.; Meldrum, Fiona C.; Colfen, Helmut; Dove, Patricia M.

    2015-07-31

    Field and laboratory observations show that crystals commonly form by the addition and attachment of particles that range from multi-ion complexes to fully formed nanoparticles. These non-classical pathways to crystallization are diverse, in contrast to classical models that consider the addition of monomeric chemical species. We review progress toward understanding crystal growth by particle attachment processes and show that multiple pathways result from the interplay of free energy landscapes and reaction dynamics. Much remains unknown about the fundamental aspects; particularly the relationships between solution structure, interfacial forces, and particle motion. Developing a predictive description that connects molecular details to ensemble behavior will require revisiting long-standing interpretations of crystal formation in synthetic systems and patterns of mineralization in natural environments.

  3. Perfect preferential orientation of nitrogen-vacancy defects in a synthetic diamond sample

    Energy Technology Data Exchange (ETDEWEB)

    Lesik, M.; Roch, J.-F. [Laboratoire Aimé Cotton, CNRS, Université Paris-Sud and Ecole Normale Supérieure de Cachan, 91405 Orsay (France); Tetienne, J.-P.; Jacques, V., E-mail: vjacques@ens-cachan.fr [Laboratoire Aimé Cotton, CNRS, Université Paris-Sud and Ecole Normale Supérieure de Cachan, 91405 Orsay (France); Laboratoire de Photonique Quantique et Moléculaire, Ecole Normale Supérieure de Cachan and CNRS UMR 8537, 94235 Cachan (France); Tallaire, A., E-mail: alexandre.tallaire@lspm.cnrs.fr; Achard, J.; Mille, V.; Gicquel, A. [Laboratoire des Sciences des Procédés et des Matériaux, CNRS and Université Paris 13, 93340 Villetaneuse (France)

    2014-03-17

    We show that the orientation of nitrogen-vacancy (NV) defects in diamond can be efficiently controlled through chemical vapor deposition growth on a (111)-oriented diamond substrate. More precisely, we demonstrate that spontaneously generated NV defects are oriented with a ∼97% probability along the [111] axis, corresponding to the most appealing orientation among the four possible crystallographic axes. Such a nearly perfect preferential orientation is explained by analyzing the diamond growth mechanism on a (111)-oriented substrate and could be extended to other types of defects. This work is a significant step towards the design of optimized diamond samples for quantum information and sensing applications.

  4. Surface finishing of ZnGeP2 single crystal by diamond tool turning method

    Science.gov (United States)

    Yue, Xiaobin; Xu, Min; Du, Wenhao; Chu, Chong

    2017-09-01

    In this work, diamond tool turning of vertical gradient freeze (VGF) grown single crystal ZnGeP2 (ZGP) was investigated. The flatness of machined ZGP surface was measured with a Zygo interferometry to be less than λ/10 and the roughness was measured with a Taloy profilermeter to be 0.7-0.9 nm. The laser-induced damage threshold was measured with a 2.07 μm wavelength pulsed laser to be >3 J/cm2.

  5. Color center fluorescence and spin manipulation in single crystal, pyramidal diamond tips

    Science.gov (United States)

    Nelz, Richard; Fuchs, Philipp; Opaluch, Oliver; Sonusen, Selda; Savenko, Natalia; Podgursky, Vitali; Neu, Elke

    2016-11-01

    We investigate bright fluorescence of nitrogen (NV)- and silicon-vacancy color centers in pyramidal, single crystal diamond tips, which are commercially available as atomic force microscope probes. We coherently manipulate NV electronic spin ensembles with T2 = 7.7(3) μs. Color center lifetimes in different tip heights indicate effective refractive index effects and quenching. Using numerical simulations, we verify enhanced photon rates from emitters close to the pyramid apex rendering them promising as scanning probe sensors.

  6. Color center fluorescence and spin manipulation in single crystal, pyramidal diamond tips

    CERN Document Server

    Nelz, Richard; Opaluch, Oliver; Sonusen, Selda; Savenko, Natalia; Podgursky, Vitali; Neu, Elke

    2016-01-01

    We investigate bright fluorescence of nitrogen (NV)- and silicon-vacancy color centers in pyramidal, single crystal diamond tips which are commercially available as atomic force microscope probes. We coherently manipulate NV electronic spin ensembles with $T_2 = 7.7(3)\\,\\mu$s. Color center lifetimes in different tip heights indicate effective refractive index effects and quenching. Using numerical simulations, we verify enhanced photon rates from emitters close to the pyramid apex; a situation promising for scanning probe sensing.

  7. Electromagnetic wave control of ceramic/resin photonic crystals with diamond structure

    Directory of Open Access Journals (Sweden)

    Soshu Kirihara, Mitsuo Takeda, Kazuaki Sakoda and Yoshinari Miyamoto

    2004-01-01

    Full Text Available Millimeter-order photonic crystals with the periodic arrangement of the dielectric constant were fabricated by infiltrating the mixed slurry of ceramics and polyester into the epoxy molds with an inverse form of a diamond structure. The epoxy molds are designed and processed by using a CAD/CAM process of stereolithography. The photonic crystals were prepared to have the diamond structure of the ceramic/polyester composite lattice, which is embedded in the epoxy matrix. The ceramic powders mixed with polyester are TiO2, SrTiO3, and BaTiO3 with high dielectric constant. It is possible to control more freely and widely the dielectric constant of the photonic crystals by this method. These ceramic/resin photonic crystals formed the complete photonic band gaps in the microwave band of 7–11 GHz, which can totally reflect the electromagnetic wave for all crystal directions. Attenuation profiles of the transmission amplitude in the band gaps were controlled with the dielectric constant of the composite lattice. The obtained results fairly agreed with the theoretical simulation of the electromagnetic wave propagation through photonic crystals.

  8. 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.

  9. Rocking curve FWHM maps of a chemically etched (0 0 1) oriented HPHT type Ib diamond crystal plate

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Y; Macrander, A T; Krasnicki, S; Chu, Y S; Maj, J; Assoufid, L; Qian, J [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2007-09-07

    Synchrotron radiation and a CCD detector were employed to map the full width at half maximum (FWHM) of rocking curves for a synthetic (0 0 1) oriented type Ib diamond plate. The plate was sawed from a diamond grown in the high-pressure-high-temperature (HPHT) process. Maps for broadening relative to a reference point on the diamond for the (2 2 4) reflection at 12 keV are reported before and after chemical etching. Significant rocking curve narrowing over most of the diamond was found, and we conclude that the diffraction performance of (0 0 1) oriented type Ib diamonds can be significantly improved over a large area by chemical etching. Stripes in the map before etching corresponded to grooves formed in the process of sawing the plate out of the as-grown stone. The FWHM map did not correlate with the surface height profile measured after {approx}10 {mu}m were removed from the surface by etching.

  10. Nanoimplantation and Purcell enhancement of single nitrogen-vacancy centers in photonic crystal cavities in diamond

    Energy Technology Data Exchange (ETDEWEB)

    Riedrich-Möller, Janine; Becher, Christoph, E-mail: christoph.becher@physik.uni-saarland.de [Universität des Saarlandes, Fachrichtung 7.2 (Experimentalphysik), Campus E 2.6, 66123 Saarbrücken (Germany); Pezzagna, Sébastien; Meijer, Jan [Universität Leipzig, Institut für Experimentalphysik II, Linnéstraße 5, 04103 Leipzig (Germany); Pauly, Christoph; Mücklich, Frank [Universität des Saarlandes, Fachrichtung 8.4 (Materialwissenschaft und Werkstofftechnik), Campus D 3.3, 66123 Saarbrücken (Germany); Markham, Matthew; Edmonds, Andrew M. [Element Six Ltd., Global Innovation Centre, Fermi Avenue, Harwell Oxford, Didcot OX11 0QR (United Kingdom)

    2015-06-01

    We present the controlled creation of single nitrogen-vacancy (NV) centers via ion implantation at the center of a photonic crystal cavity which is fabricated in an ultrapure, single crystal diamond membrane. High-resolution placement of NV centers is achieved using collimation of a 5 keV-nitrogen ion beam through a pierced tip of an atomic force microscope. We demonstrate coupling of the implanted NV centers' broad band fluorescence to a cavity mode and observe Purcell enhancement of the spontaneous emission. The results are in good agreement with a master equation model for the cavity coupling.

  11. Nanoimplantation and Purcell enhancement of single NV centers in photonic crystal cavities in diamond

    CERN Document Server

    Riedrich-Möller, Janine; Meijer, Jan; Pauly, Christoph; Mücklich, Frank; Markham, Matthew; Edmonds, Andrew M; Becher, Christoph

    2015-01-01

    We present the controlled creation of single nitrogen-vacancy (NV) centers via ion implantation at the center of a photonic crystal cavity which is fabricated in an ultrapure, single crystal diamond membrane. High-resolution placement of NV centers is achieved using collimation of a 5keV-nitrogen ion beam through a pierced tip of an atomic force microscope (AFM). We demonstrate coupling of the implanted NV centers' broad band fluorescence to a cavity mode and observe Purcell enhancement of the spontaneous emission. The results are in good agreement with a master equation model for the cavity coupling.

  12. Growth and annealing study of hydrogen-doped single diamond crystals under high pressure and high temperature

    Institute of Scientific and Technical Information of China (English)

    Li Yong; Jia Xiao-Peng; Hu Mei-Hua; Liu Xiao-Bing; Yan Bing-Min; Zhou Zhen-Xiang; Zhang Zhuang-Fei; Ma Hong-An

    2012-01-01

    A series of diamond crystals doped with hydrogen is successfully synthesized using LiH as the hydrogen source in a catalyst-carbon system at a pressure of 6.0 GPa and temperature ranging from 1255 ℃ to 1350 ℃.It is shown that the high temperature plays a key role in the incorporation of hydrogen atoms during diamond crystallization.Fourier transform infrared micro-spectroscopy reveals that most of the hydrogen atoms in the synthesized diamond are incorporated into the crystal structure as sp3-CH2-symmetric(2850 cm-1)and sp3 CH2-antisymmetric vibrations(2920 cm-1).The intensities of these peaks increase gradually with an increase in the content of the hydrogen source in the catalyst.The incorporation of hydrogen impurity leads to a significant shift towards higher frequencies of the Raman peak from 1332.06 cm-1 to 1333.05 cm-1 and gives rise to some compressive stress in the diamond crystal lattice.Furthermore,hydrogen to carbon bonds are evident in the annealed diamond,indicating that the bonds that remain throughout the annealing process and the vibration frequencies centred at 2850 and 2920 cm-1 have no observable shift.Therefore,we suggest that the spa C-H bond is rather stable in diamond crystals.

  13. Observations on the crystallization of spodumene from aqueous solutions in a hydrothermal diamond-anvil cell

    Science.gov (United States)

    Li, Jianking; Chou, I-Ming; Yuan, Shunda; Burruss, Robert A.

    2013-01-01

    Crystallization experiments were conducted in a new type of hydrothermal diamond-anvil cell (HDAC; type V) using LiAlSi2O6 (S) gel and H2O (W) as starting materials. A total of 21 experiments were performed at temperatures up to 950°C and pressures up to 788 MPa. In the samples with relatively low W/S ratios, many small crystals formed in the melt phase during cooling. In those with high W/S ratios, only a few crystals with smooth surfaces crystallized from the aqueous fluid in the presence of melt droplets, which were gradually consumed during crystal growth, indicating rapid transfer of material from the melt to the crystals through the aqueous fluid. The nucleation of crystals started at 710 (±70)°C and 520 (±80) MPa, and crystal growth ended at 570 (±40)°C and 320 (±90) MPa, with the cooling P-T path within the stability field of spodumene + quartz in the S-W system. The observed linear crystal growth rates in the aqueous phase, calculated by dividing the maximum length of a single crystal by the duration of the entire growth step, were 4.7 × 10−6 and 5.7 × 10−6 cm s−1 for the cooling rates of 0.5 and 1°C min−1, respectively. However, a rapid crystal growth rate of 3.6 × 10−5 cm s−1 in the aqueous fluid was observed when the components were supplied by nearby melt droplets. Our results show that when crystals nucleate in the aqueous fluid instead of the melt phase, there are fewer nuclei formed, and they grow much faster due to the low viscosity of the aqueous fluid, which accelerates diffusion of components for the growth of crystals. Therefore, the large crystals in granitic pegmatite can crystallize directly from aqueous fluids rather than hydrosilicate melt.

  14. Synthesis and characterization of a single diamond crystal with a high nitrogen concentration

    Institute of Scientific and Technical Information of China (English)

    Zhang Zhuang-Fei; Jia Xiao-Peng; Liu Xiao-Bing; Hu Mei-Hua; Li Yong; Yan Bing-Min; Ma Hong-An

    2012-01-01

    In this paper,we explore diamond synthesis with a series of experiments using an Fe-Ni catalyst and a P3N5 additive in the temperature range of 1250-1550 ℃ and the pressure range of 5.0-6.3 GPa.We also investigate the influence of nitrogen on diamond crystallization. Our results show that the synthesis conditions (temperature and pressure) increase with the amount of P3N5 additive increasing.The nitrogen impurity can significantly influence the diamond morphology.The diamonds stably grow into strip and lamellar shapes in the nitrogen-rich environment.The Fourier-transform infrared spectrum shows that the nitrogen concentration increases rapidly with the content of P3N5 additive increasing.By spectrum analysis,we find that with the increase of the nitrogen concentration,the Ib-type nitrogen atoms can aggregate in the A-centre form. The highest A-centre nitrogen concentration is approximately 840 ppm.

  15. Thermochemical micro imprinting of single-crystal diamond surface using a nickel mold under high-pressure conditions

    Science.gov (United States)

    Imoto, Yuji; Yan, Jiwang

    2017-05-01

    Single-crystal diamond is an important material for cutting tools, micro electro mechanical systems, optical devices, and semiconductor substrates. However, the techniques for producing microstructures on diamond surface with high efficiency and accuracy have not been established. This paper proposes a thermochemical imprinting method for transferring microstructures from a nickel (Ni) mold onto single-crystal diamond surface. The Ni mold was micro-structured by a nanoindenter and then pressed against the diamond surface under high temperature and pressure in argon atmosphere. Results show that microstructures on the Ni mold were successfully transferred onto the diamond surface, and their depth increased with both pressure and temperature. Laser micro-Raman spectroscopy, transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS) analyses indicate that a graphite layer was formed over the contact area between diamond and Ni during pressing, and after washing by a mixed acid, the graphite layer could be completely removed. This study demonstrated the feasibility of a cost-efficient fabrication method for large-area microstructures on single-crystal diamond.

  16. Modelling defect cavities formed in inverse three-dimensional rod-connected diamond photonic crystals

    Science.gov (United States)

    Taverne, M. P. C.; Ho, Y.-L. D.; Zheng, X.; Liu, S.; Chen, L.-F.; Lopez-Garcia, M.; Rarity, J. G.

    2016-12-01

    Defect cavities in 3D photonic crystal can trap and store light in the smallest volumes allowable in dielectric materials, enhancing non-linearities and cavity QED effects. Here, we study inverse rod-connected diamond (RCD) crystals containing point defect cavities using plane-wave expansion and finite-difference time domain methods. By optimizing the dimensions of the crystal, wide photonic bandgaps are obtained. Mid-bandgap resonances can then be engineered by introducing point defects in the crystal. We investigate a variety of single spherical defects at different locations in the unit cell focusing on high-refractive-index-contrast (3.3:1) inverse RCD structures; quality factors (Q-factors) and mode volumes of the resonant cavity modes are calculated. By choosing a symmetric arrangement, consisting of a single sphere defect located at the center of a tetrahedral arrangement, mode volumes < 0.06 cubic wavelengths are obtained, a record for high-index cavities.

  17. Modelling Defect Cavities Formed in Inverse Three-Dimensional Rod-Connected Diamond Photonic Crystals

    CERN Document Server

    Taverne, M P C; Zheng, X; Liu, S; Chen, L -F; Lopez-Garcia, M; Rarity, J G

    2016-01-01

    Defect cavities in 3D photonic crystal can trap and store light in the smallest volumes allowable in dielectric materials, enhancing non-linearities and cavity QED effects. Here, we study inverse rod-connected diamond (RCD) crystals containing point defect cavities using plane-wave expansion and finite-difference time domain methods. By optimizing the dimensions of the crystal, wide photonic band gaps are obtained. Mid-bandgap resonances can then be engineered by introducing point defects in the crystal. We investigate a variety of single spherical defects at different locations in the unit cell focusing on high-refractive-index contrast (3.3:1) inverse RCD structures; quality factors (Q-factors) and mode volumes of the resonant cavity modes are calculated. By choosing a symmetric arrangement, consisting of a single sphere defect located at the center of a tetrahedral arrangement, small mode volumes are obtained.

  18. Fabrication of triangular nanobeam waveguide networks in bulk diamond using single-crystal silicon hard masks

    Energy Technology Data Exchange (ETDEWEB)

    Bayn, I.; Mouradian, S.; Li, L.; Goldstein, J. A.; Schröder, T.; Zheng, J.; Chen, E. H.; Gaathon, O.; Englund, Dirk [Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, 77 Massachusetts Ave., Building 36, Cambridge, Massachusetts 02139 (United States); Lu, M.; Stein, A.; Ruggiero, C. A. [Brookhaven National Laboratory, Center for Functional Nanomaterials, Upton, New York 11973 (United States); Salzman, J. [Department of Electrical Engineering and Microelectronics Research Center, Technion, Haifa 32000 (Israel); Kalish, R. [Department of Physics and Solid State Institute, Technion, Haifa 32000 (Israel)

    2014-11-24

    A scalable approach for integrated photonic networks in single-crystal diamond using triangular etching of bulk samples is presented. We describe designs of high quality factor (Q = 2.51 × 10{sup 6}) photonic crystal cavities with low mode volume (V{sub m} = 1.062 × (λ/n){sup 3}), which are connected via waveguides supported by suspension structures with predicted transmission loss of only 0.05 dB. We demonstrate the fabrication of these structures using transferred single-crystal silicon hard masks and angular dry etching, yielding photonic crystal cavities in the visible spectrum with measured quality factors in excess of Q = 3 × 10{sup 3}.

  19. 温度对Ib型和I Ia型金刚石大单晶(100)表面特征的影响∗%Effect of temp erature on the (100) surface features of typ e Ib and typ e I Ia large single crystal diamonds

    Institute of Scientific and Technical Information of China (English)

    张贺; 肖宏宇; 李尚升; 宿太超; 胡美华; 周佑默; 樊浩天; 龚春生; 贾晓鹏; 马红安

    2015-01-01

    In this paper, by choosing FeNiMnCo alloy as a catalyst and the (100) face of a seed crystal as the growth face, high quality type Ib and type IIa large diamond single crystals (diameter about 3–4 mm) can be successfully synthesized using temperature gradient method, at 5.6 GPa pressure and different temperatures between 1250–1340 ◦C. To control the diamond crystal morphology, the growth temperature should be adjusted. Then the morphology of the synthesized large diamonds is plate-like at low temperatures, tower-like at medium temperatures, and spire tower-like at high temperatures. For the same crystal morphology, the synthetic temperature of type IIa diamond single crystals is about 30 ◦C higher than that of type Ib. The central and angularity regions of the top (100) surface, for the synthesized samples of type Ib and type IIa large diamond single crystals at different temperatures, are examined by laser Raman microscope respectively. It is found that the black lines of the type Ib and type IIa large diamond single crystals become dimmed and dense on the same top surface from center to the edge. It is indicated that the priority growth mechanism is in the angularity regions, compared with the central regions. Namely the solute of carbon is primarily precipitated in the angularity regions of the (100) surface. With increasing synthesis temperature, the black lines on the top surface (100) of type Ib diamond single crystals become gradually denser, and the characteristics of the lines are transformed from irregular distribution to typical dendritic distribution. The reason of the above results is that the rate of carbon deposition (the growth rate of diamond crystal), which is along the direction of the diamond crystal [100], will gradually rise as the synthesis temperature of the crystal is increased. The characteristics of the lines on the top surfaces (100) of type IIa large diamond single crystals, which are synthesized under different temperatures

  20. SU-E-T-485: Investigation of a Synthetic Diamond Detector for Tomotherapy Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Knill, C; Nalichowski, A; Halford, R [Karmanos Cancer Institute, Detroit, MI (United States); Zakjevskii, V; Zhuang, L [Wayne State University School of Medicine, Detroit, MI (United States); Snyder, M; Burmeister, J [Karmanos Cancer Institute, Detroit, MI (United States); Wayne State University School of Medicine, Detroit, MI (United States)

    2014-06-01

    Purpose: Tomotherapy treatments are characterized by rotational deliveries of flattening-filter free fields resulting in high-gradient dose distributions. Small volume, rotationally independent detectors are needed for accurate dosimetry. PTWs microDiamond detector, with its small sensitive volume (0.004mm{sup 3}), could potentially be an ideal detector for Tomotherapy. The microDiamond detector was tested against a small volume Exradin A1SL ion chamber for Tomotherapy open-field and IMRT commissioning measurements. Methods: Custom detector holders were fabricated to allow A1SL and microDiamond measurements in the Tomotherapy Cheese phantom and a square solid water phantom. The microDiamond rotational dependence within the Tomotherapy phantom was tested by incrementally rotating the detector in between static-gantry angle Tomotherapy irradiations. Longitudinal Tomotherapy profiles, for all field sizes, were measured with the microDiamond and A1SL detectors at 1.5cm depth in the square phantom, and compared to film. Detector axes were aligned parallel to table motion. Per TG-119 recommendations, both detectors were calibrated to known doses in phantoms and used to measure high-dose points in TG-119 H and N and Prostate plans. The measurements were compared to the treatment planning system and subsequently compared to published TG-119 confidence limits. Results: The microDiamond angular dependence was less than 0.5%. The average difference between the detectors and film-measured longitudinal profile 80–20% penumbras were 0.03+/-0.04mm and 1.36+/-0.22mm for the microDiamond and A1SL, respectively. The average difference between the detector and filmmeasured field sizes were 0.07+/-0.01mm and 0.09+/-0.02mm for the microDiamond and A1SL, respectively. The measured confidence limits were 0.023 and 0.015 for microDiamond and A1SL, respectively. TG-119 reported a confidence limit of 0.034. Conclusion: The microDiamond measured open-field longitudinal Tomotherapy profiles

  1. FEA analysis of diamond as IMCA{close_quote}s monochromator crystal

    Energy Technology Data Exchange (ETDEWEB)

    Chrzas, J.; Cimpoes, S.; Ivanov, I.N. [CSRRI, Illinois Institute of Technology, 3301 S. Dearborn Street, Chicago, IL 60616 (United States)

    1996-09-01

    A great deal of effort has been make in recent years in the field of undulator high heat load optics, and currently there are several tractable options [Rev. Sci. Instrum. {bold 69}, 2792 (1994); Nucl. Instrum. Methods A {bold 266}, 517 (1988); Nucl. Instrum. Methods A {bold 239}, 555 (1993)]. Diamond crystals offer some attractive options{endash}water as the coolant, the use of established monochromator mechanisms, simpler monochromator design as compared to the use of liquid nitrogen or gallium. The use of diamond crystals as the optical elements in a double-crystal monochromator for the IMCA-CAT and MR-CAT ID beamlines has been studied. A first crystal mounting scheme using an indium-gallium eutectic as the heat transfer medium developed in collaboration with DND-CAT and M. Hart will be presented. A FEA analysis of the IMCA-CAT ID beamline arrangement using the APS undulator A as the radiaiton source will be presented. {copyright} {ital 1996 American Institute of Physics.}

  2. Diamond Opal-Replica Photonic Crystals and Graphitic Metallic Photonic Band Gap Structures: Fabrication and Properties

    Science.gov (United States)

    Zakhidov, A. A.; Baughman, R. H.; Iqbal, Z.; Khayrullin, I. I.; Ralchenko, V. G.

    1998-03-01

    We demonstrate a new method for the formation of photonic bandgap crystals that operate at optical wavelengths. This method involves the templating of a self-assempled SiO2 lattice with diamond, graphite, or amorphous forms of carbon, followed by the removal of the original SiO2 lattice matrix by chemical means. Such carbon opal replicas are the "air type" of photonic crystal (where air replaces silica spheres) that are most favourable for photonic bandgap formation. Surprisingly, the structure of the original opal lattice having a typical cubic lattice dimension of 250 nm) is reliably replicated down to the nanometer scale using either a diamond, graphite, or amorphous carbon templated material. The optical properties of these photonic bandgap crystals are reported and compared with both theory and experimental results on other types of opal-derived lattices that we have investigated. The graphitic reverse opal is the first example of a network type metallic photonic crystal for the optical domain, for which a large photonic bandgap have been predicted.

  3. Single-crystal diamond refractive lens for focusing X-rays in two dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Antipov, S.; Baryshev, Sergey; Butler, J. E.; Antipova, O.; Liu, Zunping; Stoupin, S.

    2016-01-01

    The fabrication and performance evaluation of single-crystal diamond refractive X-ray lenses of which the surfaces are paraboloids of revolution for focusing X-rays in two dimensions simultaneously are reported. The lenses were manufactured using a femtosecond laser micromachining process and tested using X-ray synchrotron radiation. Such lenses were stacked together to form a standard compound refractive lens (CRL). Owing to the superior physical properties of the material, diamond CRLs could become indispensable wavefront-preserving primary focusing optics for X-ray free-electron lasers and the next-generation synchrotron storage rings. They can be used for highly efficient refocusing of the extremely bright X-ray sources for secondary optical schemes with limited aperture such as nanofocusing Fresnel zone plates and multilayer Laue lenses.

  4. 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.)

  5. Single-crystal diamond refractive lens for focusing X-rays in two dimensions.

    Science.gov (United States)

    Antipov, S; Baryshev, S V; Butler, J E; Antipova, O; Liu, Z; Stoupin, S

    2016-01-01

    The fabrication and performance evaluation of single-crystal diamond refractive X-ray lenses of which the surfaces are paraboloids of revolution for focusing X-rays in two dimensions simultaneously are reported. The lenses were manufactured using a femtosecond laser micromachining process and tested using X-ray synchrotron radiation. Such lenses were stacked together to form a standard compound refractive lens (CRL). Owing to the superior physical properties of the material, diamond CRLs could become indispensable wavefront-preserving primary focusing optics for X-ray free-electron lasers and the next-generation synchrotron storage rings. They can be used for highly efficient refocusing of the extremely bright X-ray sources for secondary optical schemes with limited aperture such as nanofocusing Fresnel zone plates and multilayer Laue lenses.

  6. Single Crystal Diamond Refractive Lens for Focusing X-rays in Two Dimensions

    CERN Document Server

    Antipov, S; Butler, J E; Antipova, O; Liu, Z; Stoupin, S

    2015-01-01

    We report the fabrication and performance evaluation of single crystal diamond refractive X-ray lenses with a paraboloid of rotation form factor for focusing X-rays in two dimensions simultaneously. The lenses were manufactured using a femtosecond laser micromachining process and tested using X-ray synchrotron radiation. Such lenses can be stacked together to form a traditional compound refractive lens (CRL). Due to the superior physical properties of the material, diamond CRLs are enabling and indispensable wavefront-preserving primary focusing optics for X-ray free-electron lasers and the next-generation synchrotron storage rings. They can be used for highly efficient refocusing of the extremely bright X-ray sources on secondary optical schemes with limited aperture such as nanofocusing Fresnel zone plates and multilayer Laue lenses.

  7. 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).

  8. Power scaling of Nd:YVO4 and Nd:GdVO4 disk lasers using synthetic diamond as a heat spreader.

    Science.gov (United States)

    Millar, P; Kemp, A J; Burns, D

    2009-03-15

    A newly developed low-birefringence synthetic diamond is shown to be an effective intracavity heat spreader in Nd:YVO4 and Nd:GdVO4 disk lasers. A cw output power of 25.7 W from only one double pass of the pump is reported. The diamond heat spreader is shown to increase the pump power density at which fracture occurs.

  9. Synthetic Strategies Toward DNA-Coated Colloids that Crystallize.

    Science.gov (United States)

    Wang, Yufeng; Wang, Yu; Zheng, Xiaolong; Ducrot, Étienne; Lee, Myung-Goo; Yi, Gi-Ra; Weck, Marcus; Pine, David J

    2015-08-26

    We report on synthetic strategies to fabricate DNA-coated micrometer-sized colloids that, upon thermal annealing, self-assemble into various crystal structures. Colloids of a wide range of chemical compositions, including poly(styrene), poly(methyl methacrylate), titania, silica, and a silica-methacrylate hybrid material, are fabricated with smooth particle surfaces and a dense layer of surface functional anchors. Single-stranded oligonucleotides with a short sticky end are covalently grafted onto particle surfaces employing a strain-promoted alkyne-azide cycloaddition reaction resulting in DNA coatings with areal densities an order of magnitude higher than previously reported. Our approach allows the DNA-coated colloids not only to aggregate upon cooling but also to anneal and rearrange while still bound together, leading to the formation of colloidal crystal compounds when particles of different sizes or different materials are combined.

  10. Coupling of Nitrogen-Vacancy Centers to Photonic Crystal Cavities in Monocrystalline Diamond

    CERN Document Server

    Faraon, Andrei; Huang, Zhihong; Acosta, Victor M; Beausoleil, Raymond G

    2012-01-01

    The zero-phonon transition rate of a nitrogen-vacancy center is enhanced by a factor of ~70 by coupling to a photonic crystal resonator fabricated in monocrystalline diamond using standard semiconductor fabrication techniques. Photon correlation measurements on the spectrally filtered zero-phonon line show antibunching, a signature that the collected photoluminescence is emitted primarily by a single nitrogen-vacancy center. The linewidth of the coupled nitrogen-vacancy center and the spectral diffusion are characterized using high-resolution photoluminescence and photoluminescence excitation spectroscopy.

  11. ANALYSIS OF THE FUNDAMENTAL CHARACTERISTICS OF DIAMOND-LIKE CRYSTALS AND LOW-DIMENSIONAL STRUCTURES

    Directory of Open Access Journals (Sweden)

    V.G.Litovchenko

    2004-01-01

    Full Text Available The principle has been developed for systematizing the diamond-like crystals with tetrahedral structure of the elementary cells and with valence chemical bonds, based on the calculation of the lattice constant. The approach proposed permits to predict basic parameters such as energy gap Eg, electron affinity (optical work function X, mechanical hardness H, melting temperature Tm, optical phonon frequency etc. These parameters have been calculated and the table is presented for a number of chemical compositions. For materials with mixed chemical bonds (valence and ionic the corrections can be calculated using Pouling electronegativity conception. The comparison with experiment demonstrates good agreement between the latter and the proposed procedure.

  12. Unusual paired pattern of radiohaloes on a diamond crystal from Guaniamo (Venezuela)

    Science.gov (United States)

    Schulze, Daniel J.; Nasdala, Lutz

    2016-11-01

    An octahedral diamond crystal from Guaniamo, Venezuela shows a multitude of round radiocolouration spots that indicate a remarkable formation history. Spots always occur in pairs, with similar spacing and intensity ratio between the two spots of each pair. We interpret this pattern to be the result of long-term irradiation of the stone emanating from a multitude of radioactive point sources. At some point during the irradiation, the stone must have experienced a translational movement which shifted it ca. 50 μm relative to the adjacent material [i.e., the (111) crystal face was a fault plane], after which irradiation continued. The Neoproterozoic age of the Guaniamo kimberlites and the high degree of radiation damage suggest that both of the two irradiation periods lasted over hundreds of millions of years. This interpretation is supported by results of He-irradiation experiments.

  13. Practical approach for a rod-connected diamond photonic crystal operating at optical wavelengths

    Science.gov (United States)

    Aoki, Kanna

    2009-11-01

    Production of a rod-connected diamond (RCD) photonic crystal structure in a semiconductor material is proposed. Periodic shifting of only one building block can create a complicated three-dimensional network, with a RCD structure exhibiting a full bandgap as wide as 0.20 on a gap/midgap (Δω /ωM) basis. A point defect cavity in the structure sustains single-mode resonance throughout the operative range because of its low symmetry. The resonant mode's highest quality factor (Q-factor) was calculated as 1.5×104 for a crystal of 11.5ax×4.25ay×12az for ai (i =x,y,z) representing three axes' period lengths.

  14. Radiation of high-energy electrons near crystallographic axes and planes of a diamond crystal

    Energy Technology Data Exchange (ETDEWEB)

    Avakyan, R.O.; Avakyan, E.O.; Avetisyan, A.E.

    1986-05-01

    The paper is devoted to the experimental study of high-energy electrons interaction with diamond crystals of different thicknesses at small incident angles with respect to crystallographic axes and planes. The effect of the so-called channeling phenomenon on the process of electron radiation in a crystal is studied. Results of the measurements of 4.5. GeV electrons radiation spectra at incident angles approximately O are given. For comparison, we have also presented the spectrum of the radiation on an amorphous target /sup 12/C of similar thickness. Results indicate that the low-energy part of spectra greatly surpass the amorphous spectrum with a pronounced peak structure, with peak widths being noticeably wider in the case of axial channeling than in the planar case. Spectra are measured by a No.I(Tl) total absorption detector. The experiment is performed on the Yerevan electron synchrotron beam with small angular divergence.

  15. I19, the small-molecule single-crystal diffraction beamline at Diamond Light Source.

    Science.gov (United States)

    Nowell, Harriott; Barnett, Sarah A; Christensen, Kirsten E; Teat, Simon J; Allan, David R

    2012-05-01

    The dedicated small-molecule single-crystal X-ray diffraction beamline (I19) at Diamond Light Source has been operational and supporting users for over three years. I19 is a high-flux tunable-wavelength beamline and its key details are described in this article. Much of the work performed on the beamline involves structure determination from small and weakly diffracting crystals. Other experiments that have been supported to date include structural studies at high pressure, studies of metastable species, variable-temperature crystallography, studies involving gas exchange in porous materials and structural characterizations that require analysis of the diffuse scattering between Bragg reflections. A range of sample environments to facilitate crystallographic studies under non-ambient conditions are available as well as a number of options for automation. An indication of the scope of the science carried out on the beamline is provided by the range of highlights selected for this paper.

  16. Tracking performance of a single-crystal and a polycrystalline diamond pixel-detector

    Energy Technology Data Exchange (ETDEWEB)

    Menasce, D.; et al.

    2013-06-01

    We present a comparative characterization of the performance of a single-crystal and a polycrystalline diamond pixel-detector employing the standard CMS pixel readout chips. Measurements were carried out at the Fermilab Test Beam Facility, FTBF, using protons of momentum 120 GeV/c tracked by a high-resolution pixel telescope. Particular attention was directed to the study of the charge-collection, the charge-sharing among adjacent pixels and the achievable position resolution. The performance of the single-crystal detector was excellent and comparable to the best available silicon pixel-detectors. The measured average detection-efficiency was near unity, ε = 0.99860±0.00006, and the position-resolution for shared hits was about 6 μm. On the other hand, the performance of the polycrystalline detector was hampered by its lower charge collection distance and the readout chip threshold. A new readout chip, capable of operating at much lower threshold (around 1 ke$-$), would be required to fully exploit the potential performance of the polycrystalline diamond pixel-detector.

  17. 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 ...

  18. A topological analysis of charge densities in diamond, silicon and germanium crystals

    Energy Technology Data Exchange (ETDEWEB)

    Abramov, Yu.A. [National Inst. for Research in Inorganic Materials, Tsukuba, Ibaraki (Japan); Okamura, F.P. [National Inst. for Research in Inorganic Materials, Tsukuba, Ibaraki (Japan)

    1997-03-01

    The Hansen-Coppens multipole model of charge density has been fitted to highly accurate published experimental and theoretical structure factors for diamond, silicon and germanium crystals. Analysis of both model experimental and theoretical charge densities using the resulting model parameters was performed in terms of Bader`s topological theory. The general topology of the charge density appeared to be identical for all crystals, containing the four possible types of critical points of rank three, and no non-nuclear attractors between neighboring atoms were found within achieved accuracy. Theoretical and experimental values of charge density and its Laplacian show quantitative and semiquantitative agreement, respectively, at the critical points of model charge densities. For Ge crystals, such agreement is worse at the ring critical point. These results suggest the possibility of semiquantitative (within 10-30%) study of the topological characteristics of highly accurate X-ray charge densities of crystals displaying shared interatomic interactions. Comparative topological analysis of the chemical bond in this series of crystals is discussed in terms of the quantum topological theory. (orig.).

  19. An X-Ray Diffraction Study of an Inclusion in Diamond from the Luobusha Chromite Deposit in Tibet,China

    Institute of Scientific and Technical Information of China (English)

    SHI Nicheng; BAI Wenji; MA Zhesheng; FANG Qingsong; XIONG Ming; YAN Binggang; DAI Mingquan; YANG Jingsui

    2003-01-01

    Diamond was found in podiform chromitites of ophiolite and harzburgite from Luobusha, Tibet. There are silicate inclusions in some diamond grains from this area. In the present work, the CCD (charge coupled detector) technology of X-ray powder diffraction was applied to the study of the inclusion in diamond from the ophiolite of Tibet. Diffraction patterns are obtained even though the inclusion is only 20 μm in crystal size. The results show that the inclusion in diamond consists of talc and clinochrysotile. Therefore, it is clear that the diamond from the ophiolite of Luobusha, Tibet, is natural diamond rather than a synthetic one.

  20. Twin Diamond Crystals Grown at High Temperature and High Pressure from the Fe-Ni-C System

    Institute of Scientific and Technical Information of China (English)

    尹龙卫; 袁泉; 李木森; 刘玉先; 许斌; 郝兆印

    2002-01-01

    Twin diamond crystals grown at high temperature and high pressure (HPHT) in the presence of FeNi catalyst have been examined by transmission electron microscopy (TEM). Direct observation by TEM shows that there are a large amount of twins which lie on the {111} planes in the HPHT-grown diamonds. The twins in the diamond may be formed and may extend into the inner crystal from the twin nucleus formed in the nucleation process.The twins can be formed due to the carbon atoms falling mistakenly into positions where a twin crystal can form during diamond growth, or condensation of supersaturated vacancies on the {111} plane. Some hexagonal dislocation loops related to supersaturated vacancies are found on the twins. The Moiré fringe image reveals that stacking faults terminate on the intersecting twin boundary. This suggests that, at the temperature that the HPHT diamond is grown, the bordering partial has propagated by gliding up to the twin interface, which can be described by the reaction of a Shockley partial dislocation with a twin on the {111} plane.

  1. The characterization of low energy molecular hydrogen ion—induced defects in synthetic diamond by optical absorption

    Institute of Scientific and Technical Information of China (English)

    MaZhong-Quan; AokiY; 等

    1998-01-01

    The results of optical absorption analysis of the synthetic diamonds(type Ib) which were implanted with 40 keV molecular hydrogen ions at doses of 1015-1017H/cm2(at 100K),showed that the increase of optical density(OD) of modified layer(-140nm) in UV-VIS region was dependent upon the damage level caused by ion implantation process.The range of relative optical band gap(Er.opt) around 2.0eV suggested that an amorphous carbon network structure like a-C film,which probably contains some localized subtetrabedral-coordinated clusters embedded in the fourflod(sp3) sites.was tentatively found in this layer,basing on the optical gap of carbon materials.The evolution of Er,opt with ion fluence indicated that no more hydrogenated carbon compositions were produced in as -implanted samples,while the increase of Er,opt with annealing temperature was very similar to that of hydrogen content dependence of Eopt in hydrogenately amorphous carbon(a-C:H):In addition the optical inhomogeneity of type Ib diamond has been revealed by a 2-dimension topograph in transmission mode at λ=430nm。

  2. Spin liquid in a single crystal of the frustrated diamond lattice antiferromagnet CoAl2O4

    DEFF Research Database (Denmark)

    Zaharko, O.; Christensen, Niels Bech; Cervellino, A.

    2011-01-01

    We study the evidence for spin liquid in the frustrated diamond lattice antiferromagnet CoAl2O4 by means of single-crystal neutron scattering in zero and applied magnetic fields. The magnetically ordered phase appearing below T-N = 8 K remains nonconventional down to 1.5 K. The magnetic Bragg peaks...

  3. 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.)

  4. Design of a three-dimensional photonic crystal nanocavity based on a \\langle 110\\rangle -layered diamond structure

    Science.gov (United States)

    Tajiri, Takeyoshi; Takahashi, Shun; Tandaechanurat, Aniwat; Iwamoto, Satoshi; Arakawa, Yasuhiko

    2014-01-01

    We design a three-dimensional (3D) photonic crystal (PC) nanocavity based on a \\langle 110\\rangle -layered diamond structure. The designed structure, comprised of self-sustainable layers, is suitable for fabrication by layer stacking techniques. Quality factors (Q-factors) of nanocavities were calculated for the \\langle 110\\rangle -layered diamond and a commonly-used woodpile structures, both of which are generated from the same diamond lattice with a lattice constant adiamond. The Q-factor of the designed nanocavity can reach as high as 230,000 with 35 stacked layers and a square in-plane PC area of the length of one side of 5\\sqrt{2} a^{\\text{diamond}}. This is 1.5 times higher than that of a 3D PC nanocavity based on the woodpile structure with the same in-plane PC size and with the same number of stacked layers. The higher Q-factor in the \\langle 110\\rangle -layered diamond structure originates from its stronger in-plane light confinement over the woodpile structure. The \\langle 110\\rangle -layered diamond structure will be beneficial for improving experimentally attainable Q-factors of 3D PC nanocavities particularly fabricated by a micromanipulation method.

  5. Improvement of the quality factor of single crystal diamond mechanical resonators

    Science.gov (United States)

    Liao, Meiyong; Toda, Masaya; Sang, Liwen; Teraji, Tokuyuki; Imura, Masataka; Koide, Yasuo

    2017-02-01

    Single-crystal diamond (SCD) has the potential to boost microelectromechanical system (MEMS) with unprecedented performance in terms of its intrinsic mechanical, chemical, and electronic properties, especially in the applications under extreme conditions. On the basis of the analysis of the energy dissipation in diamond mechanical resonators, the authors report on the marked improvement of the quality factor of SCD-MEMS resonators. Ion implantation assisted lift-off technique (IAL) is utilized to fabricate the SCD resonators. The quality factor of the resonator fabricated from the ion-damaged SCD layer alone is as low as 100-300 owing to the bulk or surface defects. The growth of homoepitaxial layers on the ion-implanted SCD substrates significantly improves the quality factor by more than 100 times. Cantilevers made of SCD epilayers of different thicknesses are examined. It is found that the quality factor increases with increasing the epilayer thickness. The maximum quality factor of the SCD cantilevers fabricated by the IAL technique reaches 3.9 × 104. A bilayer model is proposed to describe the variation of the quality factor.

  6. 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.

  7. A new on-line luminometer and beam conditions monitor using single crystal diamond sensors

    CERN Document Server

    CMS Collaboration

    2015-01-01

    Instrumentation near the beam-pipe requires extremely radiation hard sensors. Inside CMS two rings instrumented with 12 single crystal diamond sensors each are installed on both sides of the interaction point. The sensors are subdivided in two pads, and each pad is read out by a dedicated fast radiation hard ASIC in 130 nm CMOS technology. Due to the excellent time resolution collision products will be separated from machine induced background. In the backend a dead-time less histogramming unit is used, and a fast microTCA system with GHz sampling rate is under development. The detector will measure both the on-line luminosity and the background bunch-by-bunch. The performance of a prototype detector in a test-beam will be reported, and results from the operation during data taking will be presented.

  8. Single-crystal Diamond Detector for DT and DD plasmas diagnostic

    Science.gov (United States)

    Rebai, M.; Cazzaniga, C.; Tardocchi, M.; Grosso, G.; Croci, G.; Perelli Cippo, E.; Calvani, P.; Girolami, M.; Trucchi, D. M.; Gorini, G.

    2016-11-01

    Single-crystal Diamond Detectors (SDD) are good candidates as high-energy neutron detectors in the extreme conditions of the next generation thermonuclear fusion facilities like the ITER experiment, due to their high radiation hardness, fast response time and small size. Neutron detection in SDDs is based on the collection of electron-hole pairs produced by charged particles generated by neutron interaction on 12 C . In this work the SDD response to neutrons with energies between 2.8 and 3.8MeV was determined at the Legnaro CN accelerator at the INFN Laboratories in Legnaro (PD, Italy). This work is relevant for the characterization of SDDs response functions, which are key points for Deuterium-Deuterium and Deuterium-Tritium plasma diagnostic.

  9. Effects of a carbon convection field on large diamond growth under high-pressure high-temperature conditions

    Institute of Scientific and Technical Information of China (English)

    Hu Mei-Hua; Li Shang-Sheng; Ma Hong-An; Su Tai-Chao; Li Xiao-Lei; Hu Qiang; Jia Xiao-Peng

    2012-01-01

    Large diamond crystals were successfully synthesized by a FeNi-C system using the temperature gradient method under high-pressure high-temperature conditions.The assembly of the growth cell was improved and the growth process of diamond was investigated.Effects of the symmetry of the carbon convection field around the growing diamond crystal were investigated systematically by adjusting the position of the seed crystal in the melted catalyst/solvent.The results indicate that the morphologies and metal inclusion distributions of the synthetic diamond crystals vary obviously in both symmetric and non-symmetric carbon convection fields with temperature.Moreover,the finite element method was applied to analyze the carbon convection mode of the melted catalyst/solvent around the diamond crystal.This work is helpful for understanding the growth mechanism of diamond.

  10. Characterisation of irradiation damage and dopant distribution in synthetic diamonds by luminescence micro-spectroscopy

    CERN Document Server

    Charles, S J

    2002-01-01

    ground and two excited states. The lower energy excited state has a slow rate of decay and the second, higher energy excited state, which is thermally populated, has a high rate of decay to the ground state. The higher energy excited state has a spectrum with a local mode and the centre is metastably enhanced by exposure to UV light. DBI is not dependent on the isotope of boron used to elope the diamonds. The lines at 650.2 nm and 667.8 nm also come from the same centre as each other, designated DB2. The CVD B-doped diamond samples showed changes in boron level by approximately an order of magnitude on scales smaller than 5 mu m. These differences in boron level are due to different surface facet orientations of the grains that comprise the sample, and different facets have different rates of uptake of boron during growth. A simple, qualitative, way of showing the differences in boron level has been shown by using cathodoluminescence (CL) topography, which agrees with results from UV CL spectroscopy. Raman sp...

  11. Production and testing of a synthetic diamond film radiation dosimeter for radiotherapy

    CERN Document Server

    Fidanzio, A; Venanzi, C; Pinzari, F; Piermattei, A

    2002-01-01

    A detector, constituted by a polycrystalline chemical vapor deposited diamond film, has been made for on-line radiotherapy beam analysis in terms of dose distributions in water equivalent material. Preliminary results are reported which evidence that the leakage current can be a limiting parameter for an efficient collection of the charge carriers produced by the ionizing radiation. A signal to noise ratio near to 100 has been obtained. A priming effect similar to that found in natural diamond devices has also been evidenced, and a stable detector response was obtained after an accumulated dose of 5 Gy. The linearity has been achieved between the detector reading and the dose. The detector sensitivity resulted was equal to 77 nC/Gy per mm sup 3 of detector sensitive volume. A power law with exponent DELTA less than one has been found between detector reading and dose rate. However, when the dose rate dependence was corrected, the percentage depth doses, along an X-ray beam central axis, was in agreement with ...

  12. Generation and detection of the polarization of multi-GeV photons by use of two diamond crystals

    Science.gov (United States)

    Kirsebom, K.; Kononets, Yu. V.; Mikkelsen, U.; Møller, S. P.; Uggerhøj, E.; Worm, T.; Elsener, K.; Biino, C.; Ballestrero, S.; Sona, P.; Avakian, R. O.; Ispirian, K. A.; Taroian, S. P.; Connell, S. H.; Sellschop, J. P. F.; Vilakazi, Z. Z.

    1999-07-01

    Presented are experimental results for the difference in pair production probability (the asymmetry) for 5-150 GeV photons polarized parallel and perpendicular to a (110) plane in a 1.5 mm thick diamond crystal. The photons are produced by interaction of 150 GeV electrons with an aligned diamond crystal of 0.5 mm thickness. A significant asymmetry is found over the whole energy range, which corresponds to a high degree of linear polarization of the photons as well as a difference in the refractive index. This proof-of-principle result gives the possibility of producing high energy photons with circular polarization by use of a crystal. This might open for several opportunities in high energy physics like for instance the investigation of the contribution of the gluons to the spin of the nucleon.

  13. Large single crystal diamond grown in FeNiMnCo-S-C system under high pressure and high temperature conditions

    Science.gov (United States)

    Zhang, He; Li, Shangsheng; Su, Taichao; Hu, Meihua; Li, Guanghui; Ma, Hongan; Jia, Xiaopeng

    2016-11-01

    Large diamonds have successfully been synthesized from FeNiMnCo-S-C system at temperatures of 1255-1393 °C and pressures of 5.3-5.5 GPa. Because of the presence of sulfur additive, the morphology and color of the large diamond crystals change obviously. The content and shape of inclusions change with increasing sulfur additive. It is found that the pressure and temperature conditions required for the synthesis decrease to some extent with the increase of S additive, which results in left down of the V-shape region. The Raman spectra show that the introduction of additive sulfur reduces the quality of the large diamond crystals. The x-ray photoelectron spectroscopy (XPS) spectra show the presence of S in the diamonds. Furthermore, the electrical properties of the large diamond crystals are tested by a four-point probe and the Hall effect method. When sulfur in the cell of diamond is up to 4.0 wt.%, the resistance of the diamond is 9.628×105 Ω·cm. It is shown that the large single crystal samples are n type semiconductors. This work is helpful for the further research and application of sulfur-doped semiconductor large diamond. Project supported by the National Natural Science Foundation of China (Grant No. 51172089), the Education Department of Henan Province, China (Grant No. 12A430010), and the Fundamental Research Funds for the Universities of Henan Province, China (Grant No. NSFRF140110).

  14. Temperature and field dependent Mossbauer studies of the metallic inclusions in synthetic MDAS diamond grits

    DEFF Research Database (Denmark)

    Bharuth-Ram, K.; Hansen, Mikkel Fougt; Mørup, Steen

    2001-01-01

    at temperatures of 300 K and 80 K, in zero field and in an external field of 0.60 T, on the metallic inclusions in these grits. The Mossbauer spectra of the inclusions are rather complex, reflecting the contributions of several different magnetic phases. Our results show that the temperature variation...... order observed in the larger grits collapsing as one went to smaller grit sizes. Two sets of De Beers MDAS diamond grits of US mesh size 400-500 (d=30-38 mum) and 200-230 (d=63-75 mum) were selected for temperature- and field-dependent investigations. Transmission Mossbauer measurements were made...... of the Mossbauer spectra is not due to superparamagnetic relaxation of ferromagnetic inclusions but rather to magnetic ordering temperatures of the order of room temperature. Based on the spectral lineshapes and elemental analyses, we suggest the inclusions in the 63-75 mum grits contain iron mainly in Fe...

  15. Critical boron-doping levels for generation of dislocations in synthetic diamond

    Energy Technology Data Exchange (ETDEWEB)

    Alegre, M. P., E-mail: maripaz.alegre@uca.es; Araújo, D.; Pinero, J. C.; Lloret, F.; Villar, M. P. [Departamento de Ciencias de los Materiales e Ingeniería Metalúrgica y Química, Universidad de Cádiz, 11510 Puerto Real, Cádiz (Spain); Fiori, A.; Achatz, P.; Chicot, G.; Bustarret, E. [Université Grenoble Alpes, Institut NEEL, 25 av. des Martyrs, 38042 Grenoble (France); Jomard, F. [GEMaC, CNRS and Université de Versailles St Quentin, 45 Avenue des États-Unis, 78035 Versailles (France)

    2014-10-27

    Defects induced by boron doping in diamond layers were studied by transmission electron microscopy. The existence of a critical boron doping level above which defects are generated is reported. This level is found to be dependent on the CH{sub 4}/H{sub 2} molar ratios and on growth directions. The critical boron concentration lied in the 6.5–17.0 × 10{sup 20}at/cm{sup 3} range in the 〈111〉 direction and at 3.2 × 10{sup 21 }at/cm{sup 3} for the 〈001〉 one. Strain related effects induced by the doping are shown not to be responsible. From the location of dislocations and their Burger vectors, a model is proposed, together with their generation mechanism.

  16. Effects of Al and Ti/Cu on Synthesis of Type-Ⅱa Diamond Crystals in Ni70Mn25Co5-C System at HPHT

    Institute of Scientific and Technical Information of China (English)

    LI Shang-Sheng; LI Xiao-Lei; MA Hong-An; JIA Xiao-Peng; ZANG Chuan-Yi; TIAN Yu; ZHANG Ya-Fei; XIAO Hong-Yu; HUANG Guo-Feng; MA Li-Qiu; LI Yong

    2008-01-01

    High-quality type-Ⅱa gem diamond crystals are successfully synthesized in a Ni70Mn25Co5-C system by temperature gradient method (TGM) at about 5.5 GPa and 1560 K. Al and Ti/Cu are used as nitrogen getters respectively.While nitrogen getter Al or Ti/Cu is added into the synthesis system, some inclusions and caves tend to be introduced into the crystals. When Al is added into the solvent alloy, we would hardly gain high-quality type-Ⅱa diamond crystals with nitrogen concentration Nc<1 ppm because of the reversible reaction of Al and N at high pressure and high temperature (HPHT). However, when Ti/Cu is added into the solvent alloy, high-quality type-Ⅱa diamond crystals with Nc<1 ppm can be grown by decreasing the growth rate of diamonds.

  17. Carbide Identification in Different Regions of a Thin Metal Film Covering on an HPHT As-Grown Diamond Single Crystal from Ni-Mn-C System

    Institute of Scientific and Technical Information of China (English)

    XU Bin; CUI Jian-Jun; LI Mu-Sen; LI Cheng-Mei; CHU Fu-Min; FENG Li-Ming

    2005-01-01

    @@ Diamond single crystals were synthesized in the presence of Ni-Mn catalyst under high temperature and high pressure (HPHT). A thin metal film covering on as-grown diamond formed during diamond growth was examined using transmission electron microscopy. It was shown that phase compositions of the region near the as-grown diamond are different from those of other regions in the film. We found γ-(Ni,Mn) solid solution, diamond, Ni3C and Mn23C6 in the region near the as-grown diamond, while graphite, Mn7C3 and γ-(Ni,Mn) could be found in other regions of the film. The relationship between the diamond growth and the carbides in the film was analysed briefly. It is suggested that the carbon source for diamond growth should be closely related to the decomposition of carbides in the region near the diamond single crystal at HPHT, not being directly from that of the graphite structure.

  18. 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.

  19. System and method for forming synthetic protein crystals to determine the conformational structure by crystallography

    Science.gov (United States)

    Craig, George D.; Glass, Robert; Rupp, Bernhard

    1997-01-01

    A method for forming synthetic crystals of proteins in a carrier fluid by use of the dipole moments of protein macromolecules that self-align in the Helmholtz layer adjacent to an electrode. The voltage gradients of such layers easily exceed 10.sup.6 V/m. The synthetic protein crystals are subjected to x-ray crystallography to determine the conformational structure of the protein involved.

  20. 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.)

  1. Large-surface-area diamond (111) crystal plates for applications in high-heat-load wavefront-preserving x-ray crystal optics

    CERN Document Server

    Stoupin, S; Butler, J E; Kolyadin, A V; Katrusha, A

    2016-01-01

    We report fabrication and results of high-resolution X-ray topography characterization of diamond single crystal plates with a large surface area (10$\\times$10 mm$^2$) and (111) crystal surface orientation for applications in high-heat-load X-ray crystal optics. The plates were fabricated by laser cutting of the (111) facets of diamond crystals grown using high-pressure high-temperature method. The intrinsic crystal quality of a selected 3$\\times$7~mm$^2$ crystal region of one of the studied samples was found to be suitable for applications in wavefront-preserving high-heat-load crystal optics. The wavefront characterization was performed using sequential X-ray diffraction topography in the pseudo plane wave configuration and data analysis using rocking curve topography. The variation of the rocking curve width and peak position measured with a spatial resolution of 13$\\times$13 $\\mu m^2$ over the selected region were found to be less than one microradian.

  2. Large-surface-area diamond (111) crystal plates for applications in high-heat-load wavefront-preserving X-ray crystal optics.

    Science.gov (United States)

    Stoupin, Stanislav; Antipov, Sergey; Butler, James E; Kolyadin, Alexander V; Katrusha, Andrey

    2016-09-01

    Fabrication and results of high-resolution X-ray topography characterization of diamond single-crystal plates with large surface area (10 mm × 10 mm) and (111) crystal surface orientation for applications in high-heat-load X-ray crystal optics are reported. The plates were fabricated by laser-cutting of the (111) facets of diamond crystals grown using high-pressure high-temperature methods. The intrinsic crystal quality of a selected 3 mm × 7 mm crystal region of one of the studied samples was found to be suitable for applications in wavefront-preserving high-heat-load crystal optics. Wavefront characterization was performed using sequential X-ray diffraction topography in the pseudo plane wave configuration and data analysis using rocking-curve topography. The variations of the rocking-curve width and peak position measured with a spatial resolution of 13 µm × 13 µm over the selected region were found to be less than 1 µrad.

  3. Effect of Carbon Source with Different Graphitization Degrees on the Synthesis of Diamond

    Institute of Scientific and Technical Information of China (English)

    LIU Wan-Qiang; MA Hong-AN; LI Xiao-Lei; LINAG Zhong-Zhu; LIU Mi-Lan; LI Rui; JIA Xiao-Peng

    2007-01-01

    Using three kinds of graphites with different graphitization degrees as carbon source and Fe-Ni alloy powder as catalyst, the synthesis of diamond crystals is performed in a cubic anvil high-pressure and high-temperature apparatus (SPD-6×1200). Diamond crystals with perfect hexoctahedron shape are successfully synthesized at pressure from 5.0 to 5.5GPa and at temperature from 1570 to 1770K. The synthetic conditions, nucleation, morphology, inclusion and granularity of diamond crystals are studied. The temperature and pressure increase with the increase of the graphitization degree of graphite. The quantity of nucleation and granularity of diamonds decreases with the increase of graphitization degree of graphite under the same synthesis conditions. Moreover, according to the results of the Mossbauer spectrum, the composition of inclusions is mainly Fes C and Fe-Ni alloy phases in diamond crystals synthesized with three kinds of graphites.

  4. High-resolution magnetic field imaging with a nitrogen-vacancy diamond sensor integrated with a photonic-crystal fiber.

    Science.gov (United States)

    Fedotov, I V; Blakley, S M; Serebryannikov, E E; Hemmer, P; Scully, M O; Zheltikov, A M

    2016-02-01

    We demonstrate high-resolution magnetic field imaging with a scanning fiber-optic probe which couples nitrogen-vacancy (NV) centers in diamond to a high-numerical-aperture photonic-crystal fiber integrated with a two-wire microwave transmission line. Magnetic resonance excitation of NV centers driven by the microwave field is read out through optical interrogation through the photonic-crystal fiber to enable high-speed, high-sensitivity magnetic field imaging with sub 30 μm spatial resolution.

  5. Hyperentanglement purification and concentration assisted by diamond NV centers inside photonic crystal cavities

    Science.gov (United States)

    Ren, Bao-Cang; Deng, Fu-Guo

    2013-11-01

    Hyperentanglement has attracted much attention due to its fascinating applications in quantum communication. However, it is impossible to purify a pair of photon systems in a mixed hyperentangled state with errors in two degrees of freedom using linear optical elements only, far different from all the existing entanglement purification protocols in a degree of freedom (DOF) for quantum systems. Here, we investigate the possibility of purifying a spatial-polarization mixed hyperentangled Bell state with the errors in both the spatial-mode and polarization DOFs, resorting to the nonlinear optics of a nitrogen-vacancy (NV) center in a diamond embedded in a photonic crystal cavity coupled to a waveguide. We present the first hyperentanglement purification protocol for purifying a pair of two-photon systems in a mixed hyperentangled Bell state with the errors in two DOFs. We also propose an efficient hyperentanglement concentration protocol for a partially hyperentangled Bell pure state, which has the maximal success probability in principle. These two protocols are useful in long-distance quantum communication with hyperentanglement.

  6. First studies of 500-nm Cherenkov radiation from 255-MeV electrons in a diamond crystal

    Energy Technology Data Exchange (ETDEWEB)

    Takabayashi, Y., E-mail: takabayashi@saga-ls.jp [SAGA Light Source, 8-7 Yayoigaoka, Tosu, Saga 841-0005 (Japan); Fiks, E.I. [National Research Tomsk Polytechnic University, 634050 Tomsk (Russian Federation); Pivovarov, Yu.L. [National Research Tomsk Polytechnic University, 634050 Tomsk (Russian Federation); National Research Tomsk State University, 634050 Tomsk (Russian Federation)

    2015-06-12

    The first experiment on Cherenkov light from 255-MeV electrons passing through a 50-μm-thick diamond crystal in a special geometry allowing extraction of 500-nm Cherenkov light at a right angle with respect to the electron beam direction has been performed at the injector linac of SAGA Light Source accelerator facility. The dependence of 500-nm Cherenkov light intensity (separated by a band-pass filter) on the crystal rotation angle was measured by a CCD detector. The experimentally obtained rocking curve with an intense maximum is theoretically explained as the projector effect of Cherenkov light deflected by the exit surface of the crystal. The width of the rocking curve is explained by the convolution of the standard Tamm–Frank angular distribution of Cherenkov radiation with chromatic aberration, the multiple scattering of electrons in a crystal, and initial electron beam angular divergence. In addition, it is found that the Cherenkov light intensity did not change under the (220) planar channeling condition, which is consistent with a recent theory. - Highlights: • Cherenkov light from 255-MeV electrons in a diamond crystal has been investigated. • The Cherenkov light from channeled electrons has been observed for the first time. • The experimental results are in good agreement with theory.

  7. Synthesis of large diamond crystals containing high-nitrogen concentration at high pressure and high temperature using Ni-based solvent by temperature gradient methodHuang Guo-Feng1, Jia Xiao-Peng1,2, Li Shang-Sheng2,

    Institute of Scientific and Technical Information of China (English)

    Huang Guo-Feng; Jia Xiao-Peng; Li Shang-Sheng; Zhang Ya-Fei; Li Yong; Zhao Ming; Ma Hong-An

    2010-01-01

    This paper reprots that with Ni-based catalyst/solvent and with a dopant of NaN3>, large green single crystal diamonds with perfect shape are successfully synthesized by temperature gradient method under high pressure and high temperature in a China-type cubic anvil high-pressure apparatus (SPD-6×1200), and the highest nitrogen concentration reaches approximately 1214-1257 ppm calculated by infrared absorption spectra. The synthesis conditions are about 5.5 GPa and 1240-1300℃. The growth behaviour of diamond with high-nitrogen concentration is investigated in detail. The results show that, with increasing the content of NaN3> added in synthesis system, the width of synthesis temperature region for growth high-quality diamonds becomes narrower, and the morphology of diamond crystal is changed from cube-octahedral to octahedral at same temperature and pressure, the crystal growth rate is slowed down,nevertheless, the nitrogen concentration doped in synthetic diamond increases.

  8. The effect of substrate temperature and growth rate on the doping efficiency of single crystal boron doped diamond

    Energy Technology Data Exchange (ETDEWEB)

    Demlow, SN; Rechenberg, R; Grotjohn, T

    2014-10-01

    The substrate growth temperature dependence of the plasma gas-phase to solid-phase doping efficiency in single crystal, boron doped diamond (BDD) deposition is investigated. Single crystal diamond (SCD) is grown by microwave plasma assisted chemical vapor deposition (MPACVD) on high pressure, high temperature (HPHT) type Ib substrates. Samples are grown at substrate temperatures of 850-950 degrees C for each of five doping concentration levels, to determine the effect of the growth temperature on the doping efficiency and defect morphology. The substrate temperature during growth is shown to have a significant effect on the grown sample defect morphology, and a temperature dependence of the doping efficiency is also shown. The effect of the growth rate on the doping efficiency is discussed, and the ratio of the boron concentration in the gas phase to the flux of carbon incorporated into the solid diamond phase is shown to be a more predictive measure of the resulting boron concentration than the gas phase boron to carbon ratio that is more commonly reported. (C) 2014 Elsevier B.V. All rights reserved.

  9. Enhanced Extraction of Silicon-Vacancy Centers Light Emission Using Bottom-Up Engineered Polycrystalline Diamond Photonic Crystal Slabs.

    Science.gov (United States)

    Ondič, Lukáš; Varga, Marian; Hruška, Karel; Fait, Jan; Kapusta, Peter

    2017-03-28

    Silicon vacancy (SiV) centers are optically active defects in diamond. The SiV centers, in contrast to nitrogen vacancy (NV) centers, possess narrow and efficient luminescence spectrum (centered at ≈738 nm) even at room temperature, which can be utilized for quantum photonics and sensing applications. However, most of light generated in diamond is trapped in the material due to the phenomenon of total internal reflection. In order to overcome this issue, we have prepared two-dimensional photonic crystal slabs from polycrystalline diamond thin layers with high density of SiV centers employing bottom-up growth on quartz templates. We have shown that the spectral overlap between the narrow light emission of the SiV centers and the leaky modes extracting the emission into almost vertical direction (where it can be easily detected) can be obtained by controlling the deposition time. More than 14-fold extraction enhancement of the SiV centers photoluminescence was achieved compared to an uncorrugated sample. Computer simulation confirmed that the extraction enhancement originates from the efficient light-matter interaction between light emitted from the SiV centers and the photonic crystal slab.

  10. Use of a miniature diamond-anvil cell in high-pressure single-crystal neutron Laue diffraction

    Directory of Open Access Journals (Sweden)

    Jack Binns

    2016-05-01

    Full Text Available The first high-pressure neutron diffraction study in a miniature diamond-anvil cell of a single crystal of size typical for X-ray diffraction is reported. This is made possible by modern Laue diffraction using a large solid-angle image-plate detector. An unexpected finding is that even reflections whose diffracted beams pass through the cell body are reliably observed, albeit with some attenuation. The cell body does limit the range of usable incident angles, but the crystallographic completeness for a high-symmetry unit cell is only slightly less than for a data collection without the cell. Data collections for two sizes of hexamine single crystals, with and without the pressure cell, and at 300 and 150 K, show that sample size and temperature are the most important factors that influence data quality. Despite the smaller crystal size and dominant parasitic scattering from the diamond-anvil cell, the data collected allow a full anisotropic refinement of hexamine with bond lengths and angles that agree with literature data within experimental error. This technique is shown to be suitable for low-symmetry crystals, and in these cases the transmission of diffracted beams through the cell body results in much higher completeness values than are possible with X-rays. The way is now open for joint X-ray and neutron studies on the same sample under identical conditions.

  11. Effects of isotopic disorder on the Raman spectra of crystals: Theory and ab initio calculations for diamond and germanium

    Science.gov (United States)

    Vast, Nathalie; Baroni, Stefano

    2000-04-01

    We present a method to study the effects of isotopic composition on the Raman spectra of crystals, in which disorder is treated exactly without resorting to any kind of mean-field approximation. The Raman cross section is expressed in terms of a suitable diagonal element of the vibrational Green's function, which is accurately and efficiently calculated using the recursion technique. This method can be used in conjunction with both semiempirical lattice-dynamical models and with first-principles interatomic force constants. We have applied our technique to diamond and germanium using the most accurate interatomic force constants presently available, obtained from density-functional perturbation theory. Our method correctly reproduces the light scattering in diamond-where isotopic effects dominates over the anharmonic ones-as well as in germanium, where anharmonic effects are larger.

  12. Tool wear of a single-crystal diamond tool in nano-groove machining of a quartz glass plate

    Science.gov (United States)

    Yoshino, Masahiko; Nakajima, Satoshi; Terano, Motoki

    2015-12-01

    Tool wear characteristics of a diamond tool in ductile mode machining are presented in this paper. Nano-groove machining of a quartz glass plate was conducted to examine the tool wear rate of a single-crystal diamond tool. Effects of lubrication on the tool wear rate were also evaluated. A numerical simulation technique was developed to evaluate the tool temperature and normal stress acting on the wear surface. From the simulation results it was found that the tool temperature does not increase during the machining experiment. It is also demonstrated that tool wear is attributed to the abrasive wear mechanism, but the effect of the adhesion wear mechanism is minor in nano-groove machining. It is found that the tool wear rate is reduced by using water or kerosene as a lubricant.

  13. Comparison between beryllium and diamond-backing plates in diamond-anvil cells: Application to single-crystal X-ray diffraction high-pressure data

    DEFF Research Database (Denmark)

    Periotto, Benedetta; Nestola, Fabrizio; Balic Zunic, Tonci;

    2011-01-01

    A direct comparison between two complete intensity datasets, collected on the same sample loaded in two identical diamond-anvil pressure cells equipped, respectively, with beryllium and diamond backing plates was performed. The results clearly demonstrate that the use of diamond-backing plates...

  14. Crystallization of Synthetic Blast Furnace Slags Pertaining to Heat Recovery

    Science.gov (United States)

    Esfahani, Shaghayegh

    Heat recovery from blast furnace slags is often contradicted by another requirement, to generate amorphous slag for its use in cement production. As both the rate and extent of heat recovery and slag structure are determined by its cooling rate, a relation between the crystallization kinetics and the cooling conditions is highly desired. In this study, CaO-SiO2-Al2O3-MgO (CSAM) slags with different basicities were studied by Single Hot Thermocouple Technique (SHTT) during isothermal treatment and non-isothermal cooling. Their time-temperature-transformation (TTT) and continuous-cooling-transformation (CCT) diagrams were plotted and compared with each other. Furthermore, kinetic parameters such as the Avrami exponent (n), rate coefficient (K) and effective activation energy of crystallization (EA) were found by analysis of data obtained from in-situ observation of glassy to crystalline transformation and image analysis. Also, the dependence of nucleation and growth rates of crystalline phases were quantified as a function of time, temperature, and slag basicity. Together with the observations of crystallization front, they facilitated establishing the dominant mechanisms of crystallization. In addition to the experimental work, a mathematical model was developed and validated that predicts the amount of crystallization during cooling. A second mathematical model that calculates temperature history of slag during its cooling was coupled with the above model, to allow studying the effect of parameters such as the slag/air ratio and granule size on the heat recovery and glass content of slag.

  15. Growth of large size diamond single crystals by plasma assisted chemical vapour deposition: Recent achievements and remaining challenges

    Science.gov (United States)

    Tallaire, Alexandre; Achard, Jocelyn; Silva, François; Brinza, Ovidiu; Gicquel, Alix

    2013-02-01

    Diamond is a material with outstanding properties making it particularly suited for high added-value applications such as optical windows, power electronics, radiation detection, quantum information, bio-sensing and many others. Tremendous progresses in its synthesis by microwave plasma assisted chemical vapour deposition have allowed obtaining single crystal optical-grade material with thicknesses of up to a few millimetres. However the requirements in terms of size, purity and crystalline quality are getting more and more difficult to achieve with respect to the forecasted applications, thus pushing the synthesis method to its scientific and technological limits. In this paper, after a short description of the operating principles of the growth technique, the challenges of increasing crystal dimensions both laterally and vertically, decreasing and controlling point and extended defects as well as modulating crystal conductivity by an efficient doping will be detailed before offering some insights into ways to overcome them.

  16. Design, Build & Test of a Double Crystal Monochromator for Beamlines I09 & I23 at the Diamond Light Source

    Science.gov (United States)

    Kelly, J.; Lee, T.; Alcock, S.; Patel, H.

    2013-03-01

    A high stability Double Crystal Monochromator has been developed at The Diamond Light Source for beamlines I09 and I23. The design specification was a cryogenic, fixed exit, energy scanning monochromator, operating over an energy range of 2.1 - 25 keV using a Si(111) crystal set. The novel design concepts are the direct drive, air bearing Bragg axis, low strain crystal mounts and the cooling scheme. The instrument exhibited superb stability and repeatability on the B16 Test Beamline. A 20 keV Si(555), 1.4 μrad rocking curve was demonstrated. The DCM showed good stability without any evidence of vibration or Bragg angle nonlinearity.

  17. 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.

  18. Performance of a polarizer using synthetic mica crystal in the 12-25 nm wavelength range

    Institute of Scientific and Technical Information of China (English)

    CUI Ming-Qi; CHEN Kai; ZHAO Jia; SUN Li-Juan; XI Shi-Bo; YAN Fen

    2011-01-01

    To develop polarizer functioning in the extreme ultraviolet (EUV) and soft X-ray region, the polar- ization performance of synthetic mica has been investigated theoretically with a simulation code using Fresnel equations and optical constants from the Henke database. The reflectance of synthetic mica crystal for s and p polarization was measured to investigate its polarization performance in a home-made synchrotron radiation soft X-ray polarimeter at beamline 3W1B, Beijing Synchrotron Radiation Facility (BSRF). The reflectivity of the synthetic mica crystal at an angle of grazing incidence of 48° was obtained from the experimental data, which is about 4.8x10 at 25 nm and 6.0×10 at 12 nm, and the linear polarizance of the X-ray reflected by the synthetic mica crystal that we measured using an analyzer-rotating method increases from 80% to 96.6% in this EUV region, while higher than 98.2% in the simulation. The result indicates that this synthetic mica crystal works as a practical polarizer in this EUV region of 12-25 nm, and also in an extensive wavelength region higher than 25 nm.

  19. Deterministic coupling of a single silicon-vacancy color center to a photonic crystal cavity in diamond

    CERN Document Server

    Riedrich-Möller, Janine; Pauly, Christoph; Mücklich, Frank; Fischer, Martin; Gsell, Stefan; Schreck, Matthias; Becher, Christoph

    2014-01-01

    Deterministic coupling of single solid-state emitters to nanocavities is the key for integrated quantum information devices. We here fabricate a photonic crystal cavity around a preselected single silicon-vacancy color center in diamond and demonstrate modification of the emitters internal population dynamics and radiative quantum efficiency. The controlled, room-temperature cavity coupling gives rise to a resonant Purcell enhancement of the zero-phonon transition by a factor of 19, coming along with a 2.5-fold reduction of the emitter's lifetime.

  20. Focusing of white synchrotron radiation using large-acceptance cylindrical refractive lenses made of single – crystal diamond

    Energy Technology Data Exchange (ETDEWEB)

    Polikarpov, M., E-mail: polikarpov.maxim@mail.ru [Immanuel Kant Baltic Federal University, Nevskogo 14a, 23600 Kaliningrad (Russian Federation); Snigireva, I. [European Synchrotron Radiation Facility, 71 avenue des Martyrs, Grenoble 38043 (France); Snigirev, A. [Immanuel Kant Baltic Federal University, Nevskogo 14a, 23600 Kaliningrad (Russian Federation); European Synchrotron Radiation Facility, 71 avenue des Martyrs, Grenoble 38043 (France)

    2016-07-27

    Large-aperture cylindrical refractive lenses were manufactured by laser cutting of single-crystal diamond. Five linear single lenses with apertures of 1 mm and the depth of the structure of 1.2 mm were fabricated and tested at the ESRF ID06 beamline performing the focusing of white-beam synchrotron radiation. Uniform linear focus was stable during hours of exposure, representing such lenses as pre-focusing and collimating devices suitable for the front-end sections of today synchrotron radiation sources.

  1. The hardness of synthetic products obtained from cooled and crystallized basaltic melts (in Romanian)

    OpenAIRE

    Daniela Ogrean

    2001-01-01

    The Hardness of Synthetic Products Obtained from Cooled and Crystallized Basaltic Melts. Hardness is one of the main properties of the products obtained from cooled and crystallized basaltic melts under a controlled thermal regime. It influences the abrasion tear resistance of the resulted material. The microhardness measurements on the samples (bricks, boards, gutters, armour plates, tubes) indicated Vickers hardness value between 757–926 for the materials obtained from Şanovita basalts (Tim...

  2. Post-synthetic Anisotropic Wet-Chemical Etching of Colloidal Sodalite ZIF Crystals

    Science.gov (United States)

    Avci, Civan; Ariñez-Soriano, Javier; Carné-Sánchez, Arnau; Guillerm, Vincent; Carbonell, Carlos; Imaz, Inhar; Maspoch, Daniel

    2016-01-01

    Controlling the shape of metal-organic framework (MOF) crystals is important for understanding their crystallization and useful for myriad applications. However, despite the many advances in shaping of inorganic nanoparticles, post-synthetic shape control of MOFs and, in general, molecular crystals remains embryonic. Herein we report using a simple wet-chemistry process at room temperature to control the anisotropic etching of colloidal ZIF-8 and ZIF-67 crystals. Our work enables uniform reshaping of these porous materials into unprecedented morphologies, including cubic and tetrahedral crystals, and even hollow boxes, via acid-base reaction and subsequent sequestration of leached metal ions. Etching tests on these ZIFs reveal that etching occurs preferentially in the crystallographic directions richer in metal-ligand bonds; that, among these directions, the etching rate tends to be faster on the crystal surfaces of higher dimensionality; and that the etching can be modulated by adjusting the pH of the etchant solution. PMID:26458081

  3. A Brief Review on Environmental Application of Boron Doped Diamond Electrodes as a New Way for Electrochemical Incineration of Synthetic Dyes

    Directory of Open Access Journals (Sweden)

    J. M. Peralta-Hernández

    2012-01-01

    Full Text Available The present study was stimulated by an authoritative review on decontamination of wastewaters containing synthetic organic dyes by electrochemical methods published in Martínez-Huitle and Brillas (2009. As reviewed by the authors, there have been significant efforts on investigating the decontamination of wastewaters containing synthetic dyes by electrochemical methods, and currently, more studies are being published. A high number of electrodes have been tested in this method, including boron doped diamond (BDD anodes. In this context, many papers have demonstrated that the use of a BDD thin film in electrochemical oxidation provides total mineralization with high current efficiency of different organics in real wastewaters. And this synthetic material deposited on several supports has been recently applied to dyestuff treatment. Although, in the last two years, more reports have been published treating electrochemically synthetic dyes wastewaters using BDD, there are few reports on the use of electrooxidation processes to degrade real textile effluents. The aim of this paper is to summarize and discuss the most important and recent results available in the literature about the application of BDD electrodes for removing azo dyes in synthetic and real wastewaters.

  4. Angular distribution of the emission from ultrarelativistic electrons moving near crystallographic axes in diamond and tungsten crystals

    Energy Technology Data Exchange (ETDEWEB)

    Aleinik, A.N.; Vorobev, S.A.; Kalinin, B.N.; Kurkov, A.A.; Potylitsyn, A.P.

    1986-07-01

    Data on the angular distribution of the emission from ultrarelativistic electrons moving near crystallographic axes in diamond and tungsten crystals are reviewed. A graph is presented of the orientational dependence of soft gamma rays measured by a thin-walled ionization chamber sensitive to gamma rays with energies greater than 0.3 MeV and a radiative loss measured by a total-absorption Gauss quantometer with a threshold of about 5 MeV at an angle to the primary electron-beam direction of motion. It is concluded that knowledge of the scattering processes of ultrarelativistic electrons near crytal axes makes it easier to choose the optimum type and thickness of a crystal to achieve the maximum yield of gamma radiation into a given solid angle. 8 references.

  5. Synthetic Crystals toward New Era%面向新世纪的人工晶体

    Institute of Scientific and Technical Information of China (English)

    蒋民华

    2001-01-01

    Synthetic crystals are the basic electronic and photonic materials.This paper reviews the development of synthetic crystals in the fields of electronic,opto-electronic and photonic materials with respect to the progress of IT.In new century(Tera-Era)the central role of single crystals is and will almost certainly continue to be in global IT.%人工晶体是重要的电子、光子材料。本文结合信息技术的进步来考察电子材料、光电子材料和光子材料中人工晶体的发展。在新世纪(太元世纪)的全球信息科技的构架材料中人工晶体仍起着中心作用。

  6. Ca(Ti,Si)O3 Diamond Inclusions Crystallized From Carbonate Melts in the Transition Zone: Experimental Constraints

    Science.gov (United States)

    Armstrong, L. S.; Walter, M. J.; Keshav, S.; Bulanova, G.; Pickles, J.; Lord, O. T.; Lennie, A.

    2007-12-01

    Composite diamond inclusions consisting of coexisting endmember CaSiO3 and CaTiO3 are rare but occur in diamond populations from Juina, Brazil1-2. Phase relations show that above ~9 GPa (at 1500 K) a perovskite-structured solid solution exists between these endmembers, while at lower pressures intermediate compositions produce coexisting CaTiO3-perovskite and CaSiO3 in the walstromite structure3. Inclusions with `perovskite' stoichiometry are commonly interpreted as fragments of solid mantle from the transition zone or lower mantle4-6. Here we report on two composite diamond inclusions from Juina kimberlite, and can effectively eliminate a subsolidus origin on the basis of experimental mineral phase relations. Instead, based on new melting experiments we find that the inclusions most likely crystallized directly from Ca-rich carbonate melts. Like other workers1-2 we interpret the composite inclusions as exsolution products of a high-pressure Ca(Ti,Si)O3 perovskite stable in the transition zone. Our bulk inclusion compositions are estimated to contain 50- 65 mol% CaTiO3, and are remarkably low in MgSiO3 component at less than 0.2 mol%. Experiments have shown that in peridotite or eclogite lithologies, Ca-rich perovskite in equilibrium with an MgSiO3-phase (majorite or Mg-perovskite) have about 3 to 7 mol% MgSiO37-8. Here we report on new subsolidus laser-heated diamond anvil cell experiments at 20-50 GPa in the ternary system CaSiO3-CaTiO3-MgSiO3 that bracket the CaTi-rich limb of the solvus between Ca- and Mg-rich perovskites. All experiments were made at 2000 (±200) K for 45-75 min, and were analysed using synchrotron micro-focus X-ray diffraction. We find that the solubility of MgSiO3 in CaTi-perovskite solid solutions increases significantly with increasing CaTiO3 component. Thus, Ti-rich calcium perovskite in peridotite or eclogite lithologies should have very high, not exceptionally low, MgSiO3 component. Accordingly, a subsolidus paragenesis is unlikely for

  7. Chromatographic performance of synthetic polycrystalline diamond as a stationary phase in normal phase high performance liquid chromatography.

    Science.gov (United States)

    Peristyy, Anton; Paull, Brett; Nesterenko, Pavel N

    2015-04-24

    The chromatographic properties of high pressure high temperature synthesised diamond (HPHT) are investigated in normal phase mode of high performance liquid chromatography. Purified nonporous irregular shape particles of average particles size 1.2 μm and specific surface area 5.1 m(2) g(-1) were used for packing 100×4.6 mm ID or 50×4.6 mm ID stainless steel columns. The retention behaviour of several classes of compounds including alkyl benzenes, polyaromatic hydrocarbons (PAH), alkylphenylketones, phenols, aromatic acids and bases were studied using n-hexane-2-propanol mixtures as mobile phase. The results are compared with those observed for microdispersed sintered detonation nanodiamond (MSDN) and porous graphitic carbon (PGC). HPHT diamond revealed distinctive separation selectivity, which is orthogonal to that observed for porous graphitic carbon; while selectivities of HPHT diamond and microdispersed sintered detonation nanodiamonds are similar. Owing to non-porous particle nature, columns packed with high pressure high temperature diamond exhibited excellent mass transfer and produce separations with maximum column efficiency of 128,200 theoretical plates per meter.

  8. Effects of disorder state and interfacial layer on thermal transport in copper/diamond system

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, V., E-mail: vikas.sinha.1.ctr@us.af.mil [Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433 (United States); UES, Inc., 4401 Dayton-Xenia Road, Dayton, Ohio 45432 (United States); Gengler, J. J. [Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433 (United States); Spectral Energies, LLC, 5100 Springfield Street, Suite 301, Dayton, Ohio 45431 (United States); Muratore, C. [Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433 (United States); University of Dayton Research Institute, 300 College Park, Dayton, Ohio 45469 (United States); Spowart, J. E. [Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433 (United States)

    2015-02-21

    The characterization of Cu/diamond interface thermal conductance (h{sub c}) along with an improved understanding of factors affecting it are becoming increasingly important, as Cu-diamond composites are being considered for electronic packaging applications. In this study, ∼90 nm thick Cu layers were deposited on synthetic and natural single crystal diamond substrates. In several specimens, a Ti-interface layer of thickness ≤3.5 nm was sputtered between the diamond substrate and the Cu top layer. The h{sub c} across Cu/diamond interfaces for specimens with and without a Ti-interface layer was determined using time-domain thermoreflectance. The h{sub c} is ∼2× higher for similar interfacial layers on synthetic versus natural diamond substrate. The nitrogen concentration of synthetic diamond substrate is four orders of magnitude lower than natural diamond. The difference in nitrogen concentration can lead to variations in disorder state, with a higher nitrogen content resulting in a higher level of disorder. This difference in disorder state potentially can explain the variations in h{sub c}. Furthermore, h{sub c} was observed to increase with an increase of Ti-interface layer thickness. This was attributed to an increased adhesion of Cu top layer with increasing Ti-interface layer thickness, as observed qualitatively in the current study.

  9. Effects of Cr 3+ impurity concentration on the crystallography of synthetic emerald crystals

    Science.gov (United States)

    Lee, Pei-Lun; Huang, Eugene; Lee, Jan-Shing; Yu, Shu-Cheng

    2011-06-01

    Flux method has been adopted for the synthesis of emerald crystals using PbO-V 2O 5 as a flux in order to study the crystallography of the synthetic crystals. In general, the hue of green color of emerald deepens with the addition of Cr 3+. The molar volume of the synthesized crystals was found to increase with the incorporation of Cr 2O 3 dopant. The substitution of Cr 3+ for Al 3+ in the octahedral sites of beryl results in the expansion of a-axis, while c-axis remains nearly unchanged. The maximum Cr 2O 3-content allowed in the crystal lattice of emerald has been found to be about 3.5 wt%. When the doping Cr 2O 3-content exceeds 3.5 wt%, a significant anomaly in lattice parameters starts to take place, accompanying the precipitation of an unknown phase in the emerald matrix.

  10. Improvement of radiation stability of semi-insulating gallium arsenide crystals by deposition of diamond-like carbon films

    Science.gov (United States)

    Klyui, N. I.; Lozinskii, V. B.; Liptuga, A. I.; Izotov, V. Yu.; Han, Wei; Liu, Bingbing

    2016-12-01

    We studied the properties of optical elements for the IR spectral range based on semi-insulating gallium arsenide (SI-GaAs) and antireflecting diamond-like carbon films (DLCF). Particular attention has been paid to the effect of penetrating γ-radiation on transmission of the developed optical elements. A Co60 source and step-by-step gaining of γ-irradiation dose were used for treatment of both an initial SI-GaAs crystal and DLCF/SI-GaAs structures. It was shown that DLCF deposition essentially increases degradation resistance of the SI-GaAs-based optical elements to γ-radiation. Particularly, the transmittance of the DLCF/SI-GaAs structure after γ-irradiation with a dose 9ṡ104 Gy even exceeds that of initial structures. The possible mechanism that explains the effect of γ-radiation on the SI-GaAs crystals and the DLCF/SI-GaAs structures at different irradiation doses was proposed. The effect of small doses is responsible for non-monotonic transmission changes in both SI-GaAs crystals and DLCF/SI-GaAs structures. At further increasing the γ-irradiation dose, the variation of properties of both DLCF and SI-GaAs crystal influences on the transmission of DLCF/SI-GaAs system. At high γ-irradiation dose 1.4ṡ105 Gy, passivation of radiation defects in the SI-GaAs bulk by hydrogen diffused from DLCF leads to increasing the degradation resistance of the SI-GaAs crystals coated with DLCF as compared with the crystals without DLCF.

  11. Ultimate strength of crystals, nanoparticles and nano-ceramics having diamond-like structure

    Directory of Open Access Journals (Sweden)

    Dora Zakarian

    2016-11-01

    Full Text Available A mathematical model for calculating the interplanar interaction energy of diamond-like structure ceramics at free surface of stock material in pseudopotential method has been developed. We have considered uniaxial [111] deformation of materials and obtained the “inverse Hall–Petch’s law” for strength. It is shown that nanoceramics has higher strength than the nanoparticles included in its composition.

  12. Selective data analysis for diamond detectors in neutron fields

    Science.gov (United States)

    Weiss, Christina; Frais-Kölbl, Helmut; Griesmayer, Erich; Kavrigin, Pavel

    2017-09-01

    Detectors based on synthetic chemical vapor deposition diamond gain importance in various neutron applications. The superior thermal robustness and the excellent radiation hardness of diamond as well as its excellent electronic properties make this material uniquely suited for rough environments, such as nuclear fission and fusion reactors. The intrinsic electronic properties of single-crystal diamond sensors allow distinguishing various interactions in the detector. This can be used to successfully suppress background of γ-rays and charged particles in different neutron experiments, such as neutron flux measurements in thermal nuclear reactors or cross-section measurements in fast neutron fields. A novel technique of distinguishing background reactions in neutron experiments with diamond detectors will be presented. A proof of principle will be given on the basis of experimental results in thermal and fast neutron fields.

  13. Selective data analysis for diamond detectors in neutron fields

    Directory of Open Access Journals (Sweden)

    Weiss Christina

    2017-01-01

    Full Text Available Detectors based on synthetic chemical vapor deposition diamond gain importance in various neutron applications. The superior thermal robustness and the excellent radiation hardness of diamond as well as its excellent electronic properties make this material uniquely suited for rough environments, such as nuclear fission and fusion reactors. The intrinsic electronic properties of single-crystal diamond sensors allow distinguishing various interactions in the detector. This can be used to successfully suppress background of γ-rays and charged particles in different neutron experiments, such as neutron flux measurements in thermal nuclear reactors or cross-section measurements in fast neutron fields. A novel technique of distinguishing background reactions in neutron experiments with diamond detectors will be presented. A proof of principle will be given on the basis of experimental results in thermal and fast neutron fields.

  14. 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

  15. High-pressure crystal structure investigation of synthetic Fe2SiO4 spinel

    DEFF Research Database (Denmark)

    Nestola, F.; Balic Zunic, Tonci; Koch-Müller, M.;

    2011-01-01

    The crystal structure of Fe2SiO4 spinel at room temperature was investigated at seven different pressures by X-ray diffraction, using a diamond anvil cell to examine the influence of Fe substitution on ringwoodite behaviour at high pressure. The results compared with those of a pure Mg endmember...... show that the substitution of Fe into the spinel structure causes only small changes in the compression rate of coordination polyhedra and the distortion of the octahedron. The data show that the compression rate for the octahedron and tetrahedron in (Mg,Fe)2SiO4 can be considered statistically equal...... for FeO6 and MgO6, as well as for SiO4 in both the endmembers. This shows why almost identical bulk moduli are reported along the solid solution in recent literature....

  16. Design of a 3D photonic band gap cavity in a diamond-like inverse woodpile photonic crystal

    CERN Document Server

    Woldering, Léon A; Vos, Willem L

    2014-01-01

    We theoretically investigate the design of cavities in a three-dimensional (3D) inverse woodpile photonic crystal. This class of cubic diamond-like crystals has a very broad photonic band gap and consists of two perpendicular arrays of pores with a rectangular structure. The point defect that acts as a cavity is centred on the intersection of two intersecting perpendicular pores with a radius that differs from the ones in the bulk of the crystal. We have performed supercell bandstructure calculations with up to $5 \\times 5 \\times 5$ unit cells. We find that up to five isolated and dispersionless bands appear within the 3D photonic band gap. For each isolated band, the electric-field energy is localized in a volume centred on the point defect, hence the point defect acts as a 3D photonic band gap cavity. The mode volume of the cavities resonances is as small as 0.8 $\\lambda^{3}$ (resonance wavelength cubed), indicating a strong confinement of the light. By varying the radius of the defect pores we found that o...

  17. Hybrid Group IV Nanophotonic Structures Incorporating Diamond Silicon-Vacancy Color Centers.

    Science.gov (United States)

    Zhang, Jingyuan Linda; Ishiwata, Hitoshi; Babinec, Thomas M; Radulaski, Marina; Müller, Kai; Lagoudakis, Konstantinos G; Dory, Constantin; Dahl, Jeremy; Edgington, Robert; Soulière, Veronique; Ferro, Gabriel; Fokin, Andrey A; Schreiner, Peter R; Shen, Zhi-Xun; Melosh, Nicholas A; Vučković, Jelena

    2016-01-13

    We demonstrate a new approach for engineering group IV semiconductor-based quantum photonic structures containing negatively charged silicon-vacancy (SiV(-)) color centers in diamond as quantum emitters. Hybrid diamond-SiC structures are realized by combining the growth of nano- and microdiamonds on silicon carbide (3C or 4H polytype) substrates, with the subsequent use of these diamond crystals as a hard mask for pattern transfer. SiV(-) color centers are incorporated in diamond during its synthesis from molecular diamond seeds (diamondoids), with no need for ion-implantation or annealing. We show that the same growth technique can be used to grow a diamond layer controllably doped with SiV(-) on top of a high purity bulk diamond, in which we subsequently fabricate nanopillar arrays containing high quality SiV(-) centers. Scanning confocal photoluminescence measurements reveal optically active SiV(-) lines both at room temperature and low temperature (5 K) from all fabricated structures, and, in particular, very narrow line widths and small inhomogeneous broadening of SiV(-) lines from all-diamond nanopillar arrays, which is a critical requirement for quantum computation. At low temperatures (5 K) we observe in these structures the signature typical of SiV(-) centers in bulk diamond, consistent with a double lambda. These results indicate that high quality color centers can be incorporated into nanophotonic structures synthetically with properties equivalent to those in bulk diamond, thereby opening opportunities for applications in classical and quantum information processing.

  18. Process of negative-muon-induced formation of an ionized acceptor center ({sub μ}A){sup –} in crystals with the diamond structure

    Energy Technology Data Exchange (ETDEWEB)

    Belousov, Yu. M., E-mail: theorphys@phystech.edu [Moscow Institute of Physics and Technology (State University) (Russian Federation)

    2016-12-15

    The formation of an ionized acceptor center by a negative muon in crystals with the diamond structure is considered. The negative muon entering a target is captured by a nucleus, forming a muonic atom {sub μ}A coupled to a lattice. The appearing radiation-induced defect has a significant electric dipole moment because of the violation of the local symmetry of the lattice and changes the phonon spectrum of the crystal. The ionized acceptor center is formed owing to the capture of an electron interacting with the electric dipole moment of the defect and with the radiation of a deformation-induced local-mode phonon. Upper and lower bounds of the formation rate of the ionized acceptor center in diamond, silicon, and germanium crystals are estimated. It is shown that the kinetics of the formation of the acceptor center should be taken into account when processing μSR experimental data.

  19. Surface characterization and orientation interaction between diamond- like carbon layer structure and dimeric liquid crystals

    Science.gov (United States)

    Naradikian, H.; Petrov, M.; Katranchev, B.; Milenov, T.; Tinchev, S.

    2017-01-01

    Diamond-like carbon (DLC) and amorphous carbon films are very promising type of semiconductor materials. Depending on the hybridization sp2/sp3 ratio, the material’s band gap varies between 0.8 and 3 eV. Moreover carbon films possess different interesting for practice properties: comparable to the Silicon, Diamond like structure has 22-time better thermal conductivity etc. Here we present one type of implementation of such type nanostructure. That is one attempt for orientation of dimeric LC by using of pre-deposited DLC layer with different ratio of sp2/sp3 hybridized carbon content. It could be expected a pronounced π1-π2interaction between s and p orbital levels on the surface and the dimeric ring of LC. We present comparison of surface anchoring strengths of both orientation inter-surfaces DLC/dimeric LC and single wall carbon nanotubes (SWCNT)/dimeric LC. The mechanism of interaction of dimeric LC and activated surfaces with DLC or SWCNT will be discussed. In both cases we have π-π interaction, which in combination with hydrogen bonding, typical for the dimeric LCs, influence the LC alignment. The Raman spectroscopy data evidenced the presence of charge transfer between contacting hexagonal rings of DLC and the C = O groups of the LC molecules.

  20. 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.

  1. 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.

  2. Crystals, colloids, or molecules?: Early controversies about the origin of life and synthetic life.

    Science.gov (United States)

    Deichmann, Ute

    2012-01-01

    Crystals, colloids, and (macro-)molecules have played major roles in theoretical concepts and experimental approaches concerning the generation of life from the mid-19th century on. The notion of the crystallization of life out of a nonliving fluid, a special case of the doctrine of spontaneous generation, was most prominently incorporated into Schleiden's and Schwann's version of cell theory. Refutation at the end of the 19th century of spontaneous generation of life and cells, in particular by Pasteur, Remak, and Virchow, not only gave rise to the flourishing fields of microbiology and cytology, but it also opened up research on synthetic life. These approaches focused on growth and form and colloidal chemistry on the one hand, and on the specificity of organisms' macromolecules and chemical reactions on the other. This article analyzes the contribution of these approaches to synthetic life research and argues that researchers' philosophical predilections and basic beliefs have played important roles in the choice of experimental and theoretical approaches towards synthetic life.

  3. 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.

  4. Interface between metallic film from Fe-Ni-C system and HPHT as-grown diamond single crystal

    Institute of Scientific and Technical Information of China (English)

    许斌; 李木森; 尹龙卫; 刘玉先; 崔建军; 宫建红

    2003-01-01

    Microstructures of surface layer (near diamond) of the metallic film from Fe-Ni-C system are composed of (Fe,Ni)3C, (Fe,Ni)23C6 and γ-(Fe,Ni), from which it can be assumed that graphite isn't directly catalyzed into diamond through the film and there exists a transition phase (Fe,Ni)3C that can decompose into diamond structure. AFM morphologies on the film/diamond interface are traces preserved after carbon groups moving from the film to diamond. The morphologies on the as-grown diamond are similar to those on corresponding films, being spherical on (100) face and sawtooth-like steps on (111) face. Diamond growth rates and temperature gradients in boundary layer of the molten film at HPHT result in morphology differences.

  5. Experimental study of diamond resorption during mantle metasomatism

    Science.gov (United States)

    Fedorchuk, Yana; Schmidt, Max W.; Liebske, Christian

    2014-05-01

    Many of kimberlite-derived diamonds are partially dissolved to various degree but show similar resorption style. This resorption style has been observed in experiments with aqueous fluid at the conditions corresponding to kimberlite emplacement (1-2 GPa). At the same time, each diamond population has more than ten percent of diamond crystals with several drastically different resorption styles, which have not been observed in experiments, and may represent partial dissolution of diamonds during metasomatism in different mantle domains. Metasomatic processes modify the composition of subcratonic mantle, may trigger the formation of kimberlite magma, and result in the growth and partial dissolution of diamonds. Composition of metasomatic agents as constrained from studies of the reaction rims on mantle minerals (garnet, clinopyroxene) and experimental studies vary between carbonatitic melt, aqueous silicate melt, and CHO fluid. However, complex chemical pattern of mantle minerals and estimates of redox regime in subcratonic mantle allow different interpretations. Here we explore diamond dissolution morphology as an indicator of the composition of mantle metasomatic agents. Towards this end we examine diamond dissolution morphologies developed in experiments at the conditions of mantle metasomatism in different reacting media and compare them to the mantle-derived dissolution features of natural diamonds. The experiments were conducted in multi-anvil (Walker-Type) apparatus at 6 GPa and 1200-1500oC. Dissolution morphology of natural octahedral diamond crystals (0.5 mg) was examined in various compositions in synthetic system MgO-CaO- SiO2-CO2-H2O. The runs had the following phases present: solid crystals with fluid (various ratio of H2O-CO2-SiO2, and in the air), carbonate melt, carbonate-silicate melt, and carbonate melt with CHO fluid. Experiments produced three different styles of diamond resorption. In the presence of a fluid phase with variable proportions of H2O

  6. Graphene-based liquid-crystal microlens arrays for synthetic-aperture imaging

    Science.gov (United States)

    Wu, Yong; Hu, Wei; Tong, Qing; Lei, Yu; Xin, Zhaowei; Wei, Dong; Zhang, Xinyu; Liao, Jing; Wang, Haiwei; Xie, Changsheng

    2017-09-01

    In this paper, a new kind of liquid-crystal microlens array with graphene electrodes controlled electrically are designed and fabricated successfully. The graphene-based liquid-crystal microlens arrays (GLCMAs) exhibit excellent beam focusing performances in both the visible and near infrared (NIR) wavelength regions and also synthetic aperture imaging function. The graphene films used to fabricate the electrodes of the GLCMAs are grown by chemical vapor deposition over copper foils, demonstrating several characters of low sheet resistance and high transmittance in both wavelength ranges above. The key processes for shaping the GLCMAs include: transferring graphene films from copper foils to wafers selected, conventional UV-photolithography, ICP etching, and liquid-crystal encapsulation. Through performing common optical measurements, the point spread functions of incident lasers with different wavelength, such as red lasers of ∼600 nm, green lasers of ∼532 nm, and NIR lasers of ∼980 nm, have been obtained. Several key parameters including focal spots size, average normalized light intensity, focal length, average deviation rate and contrast ratio have been acquired and analyzed. A particular synthetic-aperture imaging based on the GLCMA is realized so as to certify a fact that a single target pattern can be constructed effectively based on some sub-aperture patterns with several tens or hundreds of micrometer scale, and thus highlight a way to fast process partial or small-zoned patterns for enhancing the detection efficiency of special targets.

  7. The crystal structures of the synthetic C-terminal octa- and dodecapeptides of trichovirin.

    Science.gov (United States)

    Gessmann, R; Benos, P; Brückner, H; Kokkinidis, M

    1999-02-01

    The structures of two synthetic peptides with sequences corresponding to the C-terminal region of the naturally occurring 14-residue peptaibol trichovirin have been determined. The crystal structures of 8- and 12-residue segments are presented and are compared with the structures of the tetrapeptide and of the 9-residue segment, which have been reported earlier. A comparison between these segments leads to the hypothesis that the three-dimensional structure of trichovirin is to a large extent determined by the properties of a periodically repeating -Aib-Pro- pattern in the sequence of the peptide.

  8. The hardness of synthetic products obtained from cooled and crystallized basaltic melts (in Romanian

    Directory of Open Access Journals (Sweden)

    Daniela Ogrean

    2001-04-01

    Full Text Available The Hardness of Synthetic Products Obtained from Cooled and Crystallized Basaltic Melts. Hardness is one of the main properties of the products obtained from cooled and crystallized basaltic melts under a controlled thermal regime. It influences the abrasion tear resistance of the resulted material. The microhardness measurements on the samples (bricks, boards, gutters, armour plates, tubes indicated Vickers hardness value between 757–926 for the materials obtained from Şanovita basalts (Timiş district and between 539–958 respectively, in case of the Racoş basalts (Braşov district. There is a certain variation of the hardness within the same sample, in various measurement points, within the theoretical limits of the hardnesses of the pyroxenes and that of the spinels.

  9. Synthetic

    Directory of Open Access Journals (Sweden)

    Anna Maria Manferdini

    2010-06-01

    Full Text Available Traditionally materials have been associated with a series of physical properties that can be used as inputs to production and manufacturing. Recently we witnessed an interest in materials considered not only as ‘true matter’, but also as new breeds where geometry, texture, tooling and finish are able to provoke new sensations when they are applied to a substance. These artificial materials can be described as synthetic because they are the outcome of various qualities that are not necessarily true to the original matter, but they are the combination of two or more parts, whether by design or by natural processes. The aim of this paper is to investigate the potential of architectural surfaces to produce effects through the invention of new breeds of artificial matter, using micro-scale details derived from Nature as an inspiration.

  10. 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

  11. 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.)

  12. Enhanced nucleation and post-growth investigations on HFCVD diamond films grown on silicon single crystals pretreated with Zr:diamond mixed slurry

    Energy Technology Data Exchange (ETDEWEB)

    Dua, A.K.; Roy, M.; Nuwad, J.; George, V.C.; Sawant, S.N

    2004-05-15

    Two sets, one deposited for {approx}20 min and other for {approx}1 h of diamond thin film samples are prepared following pretreatment of silicon substrates using mixed slurry containing different weight ratio of zirconium and diamond particles. The films are characterized ex situ using XRD, Raman spectroscopy, photoluminescence (PL), FTIR and atomic force microscopy (AFM). As evidenced from AFM topography, nucleation density as high as 2.5x10{sup 9} particles/cm{sup 2} could be achieved in spite of posttreatment cleaning of the substrates with methanol. It has been found that the nucleation density increases, while particle size and RMS surface roughness subsides with increasing metal concentration in the mixed slurry. Raman and PL spectra of both the 20 min and 1 h samples have been recorded to check the quality of the deposits. Although a significant amount non-diamond carbon impurities is found to be present mostly at the grain boundaries of the films, the concentration of defects due to [Si-V]{sup 0} complex reduces substantially for full-grown samples and also for 20 min samples pretreated with metal-rich slurries. The plausible role of the intermediate layers behind these effects has been explored.

  13. Free-Standing Nanomechanical and Nanophotonic Structures in Single-Crystal Diamond

    OpenAIRE

    Burek, Michael John

    2016-01-01

    Realizing complex three-dimensional structures in a range of material systems is critical to a variety of emerging nanotechnologies. This is particularly true of nanomechanical and nanophotonic systems, both relying on free-standing small-scale components. In the case of nanomechanics, necessary mechanical degrees of freedom require physically isolated structures, such as suspended beams, cantilevers, and membranes. For nanophotonics, elements like waveguides and photonic crystal cavities rel...

  14. Cracking the Diamond: Testing White Dwarf Crystallization Theory with BPM 37093

    Science.gov (United States)

    Metcalfe, T. S.; Montgomery, M. H.; Kanaan, A.

    2003-12-01

    More than four decades have passed since it was predicted that the cores of the coolest white dwarf stars should theoretically crystallize. This effect is one of the largest sources of uncertainty in white dwarf cooling models, which are now routinely used to estimate the ages of stellar populations in both the galactic disk and the halo. We are attempting to minimize this source of uncertainty by calibrating the models, using observations of pulsating white dwarfs. In a typical mass white dwarf model, crystallization does not begin until the surface temperature reaches 6000-8000 K. In more massive white dwarf models the effect begins at higher surface temperatures, where pulsations are observed in the ZZ Ceti (DAV) stars. The most massive DAV white dwarf presently known is BPM 37093. We are using the observed pulsation periods of this star to probe the interior and determine the size of the crystallized core empirically. We will present preliminary results from our application of a genetic-algorithm-based fitting method to address this enormous computational problem. This research was partially supported by a grant from NASA administered by the American Astronomical Society.

  15. Bismuth-ceramic nanocomposites through ball milling and liquid crystal synthetic methods

    Science.gov (United States)

    Dellinger, Timothy Michael

    Three methods were developed for the synthesis of bismuth-ceramic nanocomposites, which are of interest due to possible use as thermoelectric materials. In the first synthetic method, high energy ball milling of bismuth metal with either MgO or SiO2 was found to produce nanostructured bismuth dispersed on a ceramic material. The morphology of the resulting bismuth depended on its wetting behavior with respect to the ceramic: the metal wet the MgO, but did not wet on the SiO2. Differential Scanning Calorimetry measurements on these composites revealed unusual thermal stability, with nanostructure retained after multiple cycles of heating and cooling through the metal's melting point. The second synthesis methodology was based on the use of lyotropic liquid crystals. These mixtures of water and amphiphilic molecules self-assemble to form periodic structures with nanometer-scale hydrophilic and hydrophobic domains. A novel shear mixing methodology was developed for bringing together reactants which were added to the liquid crystals as dissolved salts. The liquid crystals served to mediate synthesis by acting as nanoreactors to confine chemical reactions within the nanoscale domains of the mesophase, and resulted in the production of nanoparticles. By synthesizing lead sulfide (PbS) and bismuth (Bi) particles as proof-of-concept, it was shown that nanoparticle size could be controlled by controlling the dimensionality of the nanoreactors through control of the liquid crystalline phase. Particle size was shown to decrease upon going from three-dimensionally percolating nanoreactors, to two dimensional sheet-like nanoreactors, to one dimensional rod-like nanoreactors. Additionally, particle size could be controlled by varying the precursor salt concentration. Since the nanoparticles did not agglomerate in the liquid crystal immediately after synthesis, bismuth-ceramic nanocomposites could be prepared by synthesizing Bi nanoparticles and mixing in SiO2 particles which

  16. 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...

  17. Growth and characterization of large, high quality single crystal diamond substrates via microwave plasma assisted chemical vapor deposition

    Science.gov (United States)

    Nad, Shreya

    Single crystal diamond (SCD) substrates can be utilized in a wide range of applications. Important issues in the chemical vapor deposition (CVD) of such substrates include: shrinking of the SCD substrate area, stress and cracking, high defect density and hence low electronic quality and low optical quality due to high nitrogen impurities. The primary objective of this thesis is to begin to address these issues and to find possible solutions for enhancing the substrate dimensions and simultaneously improving the quality of the grown substrates. The deposition of SCD substrates is carried out in a microwave cavity plasma reactor via the microwave plasma assisted chemical vapor deposition technique. The operation of the reactor was first optimized to determine the safe and efficient operating regime. By adjusting the matching of the reactor cavity with the help of four internal tuning length variables, the system was further matched to operate at a maximum overall microwave coupling efficiency of ˜ 98%. Even with adjustments in the substrate holder position, the reactor remains well matched with a coupling efficiency of ˜ 95% indicating good experimental performance over a wide range of operating conditions. SCD substrates were synthesized at a high pressure of 240 Torr and with a high absorbed power density of 500 W/cm3. To counter the issue of shrinking substrate size during growth, the effect of different substrate holder designs was studied. An increase in the substrate dimensions (1.23 -- 2.5 times) after growth was achieved when the sides of the seeds were shielded from the intense microwave electromagnetic fields in a pocket holder design. Using such pocket holders, high growth rates of 16 -- 32 mum/hr were obtained for growth times of 8 -- 72 hours. The polycrystalline diamond rim deposition was minimized/eliminated from these growth runs, hence successfully enlarging the substrate size. Several synthesized CVD SCD substrates were laser cut and separated

  18. On-Chip Diamond Raman Laser

    CERN Document Server

    Latawiec, Pawel; Burek, Michael J; Hausmann, Birgit J M; Bulu, Irfan; Loncar, Marko

    2015-01-01

    Synthetic single-crystal diamond has recently emerged as a promising platform for Raman lasers at exotic wavelengths due to its giant Raman shift, large transparency window and excellent thermal properties yielding a greatly enhanced figure-of-merit compared to conventional materials. To date, diamond Raman lasers have been realized using bulk plates placed inside macroscopic cavities, requiring careful alignment and resulting in high threshold powers (~W-kW). Here we demonstrate an on-chip Raman laser based on fully-integrated, high quality-factor, diamond racetrack micro-resonators embedded in silica. Pumping at telecom wavelengths, we show Stokes output discretely tunable over a ~100nm bandwidth around 2-{\\mu}m with output powers >250 {\\mu}W, extending the functionality of diamond Raman lasers to an interesting wavelength range at the edge of the mid-infrared spectrum. Continuous-wave operation with only ~85 mW pump threshold power in the feeding waveguide is demonstrated along with continuous, mode-hop-fr...

  19. Fast ion energy distribution from third harmonic radio frequency heating measured with a single crystal diamond detector at the Joint European Torus

    Energy Technology Data Exchange (ETDEWEB)

    Nocente, M.; Rebai, M.; Gorini, G. [EUROfusion Consortium, JET, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Dipartimento di Fisica “G. Occhialini,” Università degli Studi di Milano-Bicocca, Milano (Italy); Istituto di Fisica del Plasma “P. Caldirola,” Consiglio Nazionale delle Ricerche, Milano (Italy); Cazzaniga, C. [EUROfusion Consortium, JET, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Istituto di Fisica del Plasma “P. Caldirola,” Consiglio Nazionale delle Ricerche, Milano (Italy); Rutherford Appleton Laboratory, ISIS Facility, Didcot (United Kingdom); Tardocchi, M.; Giacomelli, L.; Muraro, A. [EUROfusion Consortium, JET, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Istituto di Fisica del Plasma “P. Caldirola,” Consiglio Nazionale delle Ricerche, Milano (Italy); Binda, F.; Eriksson, J. [EUROfusion Consortium, JET, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Department of Physics and Astronomy, Uppsala University, Uppsala (Sweden); Sharapov, S. [EUROfusion Consortium, JET, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); CCFE, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB (United Kingdom); Collaboration: (EUROfusion Consortium, JET, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom)

    2015-10-15

    Neutron spectroscopy measurements with a single crystal diamond detector have been carried out at JET, for the first time in an experiment aimed at accelerating deuterons to MeV energies with radio frequency heating at the third harmonic. Data are interpreted by means of the expected response function of the detector and are used to extract parameters of the highly non-Maxwellian distribution function generated in this scenario. A comparison with observations using a time of flight and liquid scintillator neutron spectrometers is also presented. The results demonstrate the capability of diamond detectors to contribute to fast ion physics studies at JET and are of more general relevance in view of the application of such detectors for spectroscopy measurements in the neutron camera of next step tokamak devices.

  20. Fast ion energy distribution from third harmonic radio frequency heating measured with a single crystal diamond detector at the Joint European Torus.

    Science.gov (United States)

    Nocente, M; Cazzaniga, C; Tardocchi, M; Binda, F; Eriksson, J; Giacomelli, L; Muraro, A; Rebai, M; Sharapov, S; Gorini, G

    2015-10-01

    Neutron spectroscopy measurements with a single crystal diamond detector have been carried out at JET, for the first time in an experiment aimed at accelerating deuterons to MeV energies with radio frequency heating at the third harmonic. Data are interpreted by means of the expected response function of the detector and are used to extract parameters of the highly non-Maxwellian distribution function generated in this scenario. A comparison with observations using a time of flight and liquid scintillator neutron spectrometers is also presented. The results demonstrate the capability of diamond detectors to contribute to fast ion physics studies at JET and are of more general relevance in view of the application of such detectors for spectroscopy measurements in the neutron camera of next step tokamak devices.

  1. 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)

  2. Electrical Conductivity of Synthetic Quartz Crystals at High Temperature and Pressure from Complex Impedance Measurements

    Institute of Scientific and Technical Information of China (English)

    王多君; 李和平; 刘丛强; 易丽; 丁东业; 苏根利; 张卫刚

    2002-01-01

    An electrical conductivity measurement system under high-pressure conditions with a multi-anvil high-pressure apparatus by an ac complex impedance method was set up. With this system, we have successfully measured the electrical conductivity of synthetic quartz under pressure up to approximately 1.0 GPa in the temperature range 661-987K. The values of electrical conductivity decrease with the increasing pressure and increase with the increasing temperature. The activation enthalpies for the α-quartz crystals are 1.10-1.28eV. The electrical conductivity of α-quartz is ionic, with Na ions moving in channels parallel to the c-axis being the predominant current carrier.

  3. Temperature-related performance of Yb3+:YAG disc lasers and optimum design for diamond cooling

    Institute of Scientific and Technical Information of China (English)

    Cao Ding-Xiang; Yu Hai-Wu; Zheng Wan-Guo; He Shao-Bo; Wang Xiao-Feng

    2006-01-01

    In this paper the temperature-related performances of the Yb3+:YAG disc laser has been investigated based on quasi-three level rate equation model. A compact diamond window cooling scheme also has been demonstrated. In this cooling scheme, laser disc is placed between two thin discs of single crystal synthetic diamond, the heat transfer from Yb3+:YAG to the diamond, in the direction of the optical axis, and then rapidly conducted radically outward through the diamond to the cooling water at the circumference of the diamond/Yb3+ :YAG assembly. Simulation results show that increasing the thickness of the diamond and the overlap-length (between diamond and water) decreases the disc temperature. Therefore a 0.3-0.5 mm thick diamond window with the overlap-length of 1.5-2.0 mm will provide acceptable cost effective cooling, e.g., with a pump intensity of 15 kW/cm2 and repetitive rate of 10 Hz, to keep the maximum temperature of the lasing disc below a reasonable value (310K), the heat exchange coefficient of water should be about 3000 W/m2K.

  4. A new on-line luminometer and beam conditions monitor using single crystal diamond sensors

    CERN Document Server

    Karacheban, Olena

    2015-01-01

    Instrumentation near the beam-pipe requires extremely radiation hardsensors. Inside CMS two rings instrumented with 12 single crystal diamondsensors each are installed on both sides of the interaction point. Thesensors are subdivided in two pads, and each pad is read out by adedicated fast radiation hard ASIC in 130 nm CMOS technology.Due to the excellent time resolution collision products will be separatedfrom machine induced background. In the backend a dead-time lesshistogramming unit is udsed, and a fast microTCA system with GHz samplingrate is under development.The detector will measure both the on-line luminosity and the backgroundbunch-by-bunch.The performance of a prototype detector in a test-beam will be reported,and results from the operation during data taking will be presented.

  5. 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.

  6. Lattice dynamics of diamond-like crystals from a tight-binding calculation of valence bands

    Science.gov (United States)

    Roman, R.; Pascual, J.

    1988-11-01

    We report on the results of calculations of the TA(X) phonon energy in the series of C, Si, Ge, Sn homopolar crystals. The starting point is the tight-binding model for the electronic Hamiltonian where Es and Ep are taken to be the free atomic energies while the interatomic matrix elements are described by a universal d-2 Harrison's scaling law. The change of the total energy with the atomic distortion is given in terms of changes in the valence band energy and changes in the overlap energy. The numerical calculations for Si gives U1 = -21.77eV and U2 = 60.44eV, close to the values predicted by Harrison U1 = -17.76eV and U2 = 53.28eV. The calculations of the TA(X) phonon energy gives (in the case the interatomic distances are held constant): 26.09 THz (C), 6.46 THz (Si), 3.37THz (Ge) and 1.91 THz (Sn), in reasonably good agreement with the experimental results 24.1 THz (C), 4.49 THz (Si), 2.39 THz (Ge) and 1.26 THz (Sn).

  7. 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.

  8. Radiation emission and its influence on the motion of multi-GeV electrons and positrons incident on a single diamond crystal

    CERN Document Server

    Kirsebom, K; Uggerhøj, Erik; Elsener, K; Ballestrero, S; Sona, P; Connell, S H; Sellschop, J P Friedel; Vilakazi, Z Z

    2001-01-01

    A few years ago the CERN NA-43 collaboration installed an upgraded detector system which allows a detailed analysis of the particle motion before, during and after penetration of a crystal. Also, essentially perfect diamond crystals were produced by the collaborators from Schonland Research Centre. These facts have led to new and very detailed investigations of QED-processes in strong crystalline fields. Along axial directions the radiation emission is enhanced by more than two orders of magnitude. For incidence on a 0.7 mm thick diamond crystal of well-aligned 149 GeV electrons, 35% give rise to a high energy photon peak at approximately=120 GeV. For 243 GeV electrons and approximately=200 GeV photons, this number decreases to 25%-which may be an indication of quantum suppression. Different measurements of the photon multiplicities show that in most cases positrons and electrons emit equal number of photons. The dramatic radiation emission leads to a strong reduction in transverse energy and all electrons in...

  9. Experimental investigation of photon multiplicity and radiation cooling for 150 GeV electrons/positrons traversing diamond and Si crystals

    Science.gov (United States)

    Kirsebom, K.; Medenwaldt, R.; Mikkelsen, U.; Møller, S. P.; Paludan, K.; Uggerhøj, E.; Worm, T.; Elsener, K.; Ballestrero, S.; Sona, P.; Romano, J.; Connell, S. H.; Sellschop, J. P. F.; Avakian, R. O.; Avetisian, A. E.; Taroian, S. P.

    1996-10-01

    Detailed experimental investigations of photon multiplicities for 150 GeV electrons/positrons traversing thin diamond and Si crystals have been performed. Along axial directions up to 10 photons are emitted in 1.5 mm diamond for a radiative energy loss larger than 4 GeV. This corresponds to a mean free path for photon emission of about two orders of magnitude shorter than in an amorphous target. This is in agreement with an enhanced radiative energy loss of ˜ 30 times that in amorphous targets. The strongly enhanced photon emission leads to radiation cooling which can result in particles exiting the crystal with a reduced angle to the axis. For incidences along planar directions the average multiplicity is still above one, even for the thinnest crystals used in the present experiment, so a single-photon spectrum can only be obtained for thicknesses ≤50 μm, which, on the other hand, is comparable to the coherence lengths for GeV photons, leading to destruction of the coherent effects.

  10. Relationship between the orientation of texture and heteroepitaxy of diamond and related materials films on silicon single crystal and the valence electron structure of the interface

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Diamond and cubic boron nitride films have already been applied practically because of their excellent properties. The specific orientations of the films have special meaning on their application in optics and microelectronics fields. In this paper, the relative electron density differences of the interface between the different crystal planes of silicon substrate and those of diamond and cubic boron films are calculated with the empirical electron theory in solids and molecules. Analyses on the calculation results show that in the range of the researched films, the smaller the relative electron density difference between the film and the substrate is, the stabler the film is in thermodynamics. Therefore, the electron density difference is the essential factor of determining the orientation of the texture and heteroepitaxy of the films. The deductions accord well with the experimental facts. The calculation methods and the theory not only provide a new angle of view for the research of the growth mechanism of diamond film and cubic boron nitride film on the silicon substrate, but also provide a possible direction for the prediction of the orientation of other films.

  11. Electrical Conductivity Of Diamond Up To 1,200 Degrees C

    Science.gov (United States)

    Vandersande, Jan W.; Zoltan, Leslie D.

    1993-01-01

    Report discusses measurements of electrical conductivities of two synthetic diamond films, three synthetic diamondlike films, and two natural type IIa diamonds at temperatures from ambient to 1,200 degrees C. Measurements performed to compare electrical conductivities of state-of-the-art diamond films with those of natural insulating diamond, particularly at temperatures above 700 degrees C.

  12. 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.

  13. 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.

  14. Effects of titanium coating on property of diamond

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The titanium film was coated on the surface of diamond crystal in order to improve the chemical properties of diamond and the effect of titanium coating on the property of diamond was discussed. The anti-impacting strength, the oxidization process and the soakage property between vitrified bond and diamond were investigated. It is found that, when the titanium film is coated on the surface of diamond crystal, the soakage angle between vitrified bond and diamond decreases from 39.5° to 34.5° at 993 K, and the oxidization degree on the surface of diamonds is lowered greatly.

  15. 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)

  16. Freeform Fabrication of Magnetophotonic Crystals with Diamond Lattices of Oxide and Metallic Glasses for Terahertz Wave Control by Micro Patterning Stereolithography and Low Temperature Sintering

    Directory of Open Access Journals (Sweden)

    Maasa Nakano

    2013-04-01

    Full Text Available Micrometer order magnetophotonic crystals with periodic arranged metallic glass and oxide glass composite materials were fabricated by stereolithographic method to reflect electromagnetic waves in terahertz frequency ranges through Bragg diffraction. In the fabrication process, the photo sensitive acrylic resin paste mixed with micrometer sized metallic glass of Fe72B14.4Si9.6Nb4 and oxide glass of B2O3·Bi2O3 particles was spread on a metal substrate, and cross sectional images of ultra violet ray were exposed. Through the layer by layer stacking, micro lattice structures with a diamond type periodic arrangement were successfully formed. The composite structures could be obtained through the dewaxing and sintering process with the lower temperature under the transition point of metallic glass. Transmission spectra of the terahertz waves through the magnetophotonic crystals were measured by using a terahertz time domain spectroscopy.

  17. 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

  18. Natural occurrence of pure nano-polycrystalline diamond from impact crater.

    Science.gov (United States)

    Ohfuji, Hiroaki; Irifune, Tetsuo; Litasov, Konstantin D; Yamashita, Tomoharu; Isobe, Futoshi; Afanasiev, Valentin P; Pokhilenko, Nikolai P

    2015-10-01

    Consolidated bodies of polycrystalline diamond with grain sizes less than 100 nm, nano-polycrystalline diamond (NPD), has been experimentally produced by direct conversion of graphite at high pressure and high temperature. NPD has superior hardness, toughness and wear resistance to single-crystalline diamonds because of its peculiar nano-textures, and has been successfully used for industrial and scientific applications. Such sintered nanodiamonds have, however, not been found in natural mantle diamonds. Here we identified natural pure NPD, which was produced by a large meteoritic impact about 35 Ma ago in Russia. The impact diamonds consist of well-sintered equigranular nanocrystals (5-50 nm), similar to synthetic NPD, but with distinct [111] preferred orientation. They formed through the martensitic transformation from single-crystal graphite. Stress-induced local fragmentation of the source graphite and subsequent rapid transformation to diamond in the limited time scale result in multiple diamond nucleation and suppression of the overall grain growth, producing the unique nanocrystalline texture of natural NPD. A huge amount of natural NPD is expected to be present in the Popigai crater, which is potentially important for applications as novel ultra-hard material.

  19. Natural occurrence of pure nano-polycrystalline diamond from impact crater

    Science.gov (United States)

    Ohfuji, Hiroaki; Irifune, Tetsuo; Litasov, Konstantin D.; Yamashita, Tomoharu; Isobe, Futoshi; Afanasiev, Valentin P.; Pokhilenko, Nikolai P.

    2015-10-01

    Consolidated bodies of polycrystalline diamond with grain sizes less than 100 nm, nano-polycrystalline diamond (NPD), has been experimentally produced by direct conversion of graphite at high pressure and high temperature. NPD has superior hardness, toughness and wear resistance to single-crystalline diamonds because of its peculiar nano-textures, and has been successfully used for industrial and scientific applications. Such sintered nanodiamonds have, however, not been found in natural mantle diamonds. Here we identified natural pure NPD, which was produced by a large meteoritic impact about 35 Ma ago in Russia. The impact diamonds consist of well-sintered equigranular nanocrystals (5-50 nm), similar to synthetic NPD, but with distinct [111] preferred orientation. They formed through the martensitic transformation from single-crystal graphite. Stress-induced local fragmentation of the source graphite and subsequent rapid transformation to diamond in the limited time scale result in multiple diamond nucleation and suppression of the overall grain growth, producing the unique nanocrystalline texture of natural NPD. A huge amount of natural NPD is expected to be present in the Popigai crater, which is potentially important for applications as novel ultra-hard material.

  20. Natural occurrence of pure nano-polycrystalline diamond from impact crater

    Science.gov (United States)

    Ohfuji, Hiroaki; Irifune, Tetsuo; Litasov, Konstantin D.; Yamashita, Tomoharu; Isobe, Futoshi; Afanasiev, Valentin P.; Pokhilenko, Nikolai P.

    2015-01-01

    Consolidated bodies of polycrystalline diamond with grain sizes less than 100 nm, nano-polycrystalline diamond (NPD), has been experimentally produced by direct conversion of graphite at high pressure and high temperature. NPD has superior hardness, toughness and wear resistance to single-crystalline diamonds because of its peculiar nano-textures, and has been successfully used for industrial and scientific applications. Such sintered nanodiamonds have, however, not been found in natural mantle diamonds. Here we identified natural pure NPD, which was produced by a large meteoritic impact about 35 Ma ago in Russia. The impact diamonds consist of well-sintered equigranular nanocrystals (5–50 nm), similar to synthetic NPD, but with distinct [111] preferred orientation. They formed through the martensitic transformation from single-crystal graphite. Stress-induced local fragmentation of the source graphite and subsequent rapid transformation to diamond in the limited time scale result in multiple diamond nucleation and suppression of the overall grain growth, producing the unique nanocrystalline texture of natural NPD. A huge amount of natural NPD is expected to be present in the Popigai crater, which is potentially important for applications as novel ultra-hard material. PMID:26424384

  1. 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.

  2. 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

  3. 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...

  4. Study on characteristic parameters influencing laser-induced damage threshold of KH(2)PO(4) crystal surface machined by single point diamond turning.

    Science.gov (United States)

    Chen, Mingjun; Li, Mingquan; Cheng, Jian; Jiang, Wei; Wang, Jian; Xu, Qiao

    2011-12-01

    It has fundamental meaning to find the elements influencing the laser-induced damage threshold (LIDT) of KH(2)PO(4) (KDP) crystal and to provide suitable characterization parameters for these factors in order to improve the LIDT of KDP. Using single-point diamond turning (SPDT) to process the KDP crystal, the machined surface quality has important effects on its LIDT. However, there are still not suitable characteristic parameters of surface quality of KDP to correspond with the LIDT nowadays. In this paper, guided by the Fourier model theory, we study deeply the relationship between the relevant characteristic parameters of surface topography of KDP crystal and the experimental LIDT. Research results indicate that the waviness rather than the roughness is the leading topography element on the KDP surface machined by the SPDT method when the LIDT is considered and the amplitude of micro-waviness has greater influence on the light intensity inside the KDP crystal within the scope of dangerous frequencies between (180 μm)(-1) and (90 μm)(-1); with suitable testing equipment, the characteristic parameters of waviness amplitude, such as the arithmetical mean deviation of three-dimensional profile S(a) or root mean square deviation of three-dimensional contour S(q), are able to be considered as suitable parameters to reflect the optical quality of the machined surface in order to judge approximately the LIDT of the KDP surface and guide the machining course.

  5. 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...

  6. Coherent radiation from 70 GeV and 150 GeV electrons and positrons traversing diamond and Si crystals near axial and planar directions

    Science.gov (United States)

    Medenwaldt, R.; Møller, S. P.; Uggerhøj, E.; Worm, T.; Elsener, K.; Sona, P.; Connell, S. H.; Sellschop, J. P. F.; Avakian, R. O.; Avetisian, A. E.; Taroian, S. P.

    1995-10-01

    Channeling radiation and energy loss for 150 GeV electrons and positrons incident on a 0.5 mm thick diamond and a 0.6 mm thick Si crystal have been measured — near axial and planar directions. It is found that yields from well channeled electrons are enhanced by a factor of two, and those for positrons are reduced by a factor of five, as compared to yields outside the channeling region. The experimental critical angle for channeling agrees very well with the Lindhard angle ψ1. For incidence along planes and close to axial directions, the overall picture of the radiation spectra for electrons and positrons is the same for the high-energy photons, where a strongly enhanced peak is found, as was first discovered in an earlier electron experiment. In diamond, the standard coherent bremsstrahlung has been measured close to the 110 planes but for 10 mrad and 50 mrad from the axis. These experimental results agree well with calculations using the Born approximation.

  7. TECHNIQUE OF ESTIMATE OF ABSORPTION COEFFICIENT LASER RADIATION IN BORON DOPED DIAMONDS BY INTENSITY OF RAMAN SCATTERING

    Directory of Open Access Journals (Sweden)

    O. N. Poklonskaya

    2013-01-01

    Full Text Available Results of measurements of Raman scattering at the room temperature in air in boron doped synthetic diamonds (five with boron concentrations 2·1017; 6·1017; 2·1018; 1,7·1019; 1·1020 cm–3 and one intentionally undoped are presented. The laser with wavelength 532 nm was used for Raman scattering excitation. Dependences of integral intensity and halfwidth of diamond Raman line with respect to the doping level are presented. In the geometrical optics approximation an expression for doped to undoped integral intensity ratio is obtained. Qualitative estimates of conductivity of the studied samples are conducted. The obtained results can be applied for mapping of near-surface laser radiation absorption coefficient of synthetic single crystal diamonds and for their quality control.

  8. Radiation emission and its influence on the motion of multi-GeV electrons and positrons incident on a single diamond crystal

    Energy Technology Data Exchange (ETDEWEB)

    Kirsebom, K.; Mikkelsen, U.; Uggerhoej, E. E-mail: ugh@ifa.au.dk; Elsener, K.; Ballestrero, S.; Sona, P.; Connell, S.H.; Sellschop, J.P.F.; Vilakazi, Z.Z

    2001-04-01

    A few years ago the CERN NA-43 collaboration installed an upgraded detector system which allows a detailed analysis of the particle motion before, during and after penetration of a crystal. Also, essentially perfect diamond crystals were produced by the collaborators from Schonland Research Centre. These facts have led to new and very detailed investigations of QED-processes in strong crystalline fields. Along axial directions the radiation emission is enhanced by more than two orders of magnitude. For incidence on a 0.7 mm thick diamond crystal of well-aligned 149 GeV electrons, 35% give rise to a high energy photon peak at {approx_equal}120 GeV. For 243 GeV electrons and {approx_equal}200 GeV photons, this number decreases to 25% - which may be an indication of quantum suppression. Different measurements of the photon multiplicities show that in most cases positrons and electrons emit equal number of photons. The dramatic radiation emission leads to a strong reduction in transverse energy and all electrons incident within the critical angle are captured to high lying channeling states and exit at channeling angles corresponding to their final energy - a completely new result for negatively charged particles. For the first time, we present an analysis where the photon is used as a 'messenger' for the transverse energy of the electron during the formation time and we conclude that the more energetic photons are created closer to the string and emitted in the axial direction - in contrast to earlier calculations using the Dirac equation. The strongly enhanced radiation emission leads to angular cooling for electrons but angular heating for positrons and we show that at higher electron energies the cooling becomes stronger as expected from theory. For electrons, the radiative cooling gives rise to a capture of above-barrier particles into the channeled beam. The total radiative energy loss is shown as not to follow the {gamma}{sup 2}-law expected from

  9. Radiation emission and its influence on the motion of multi-GeV electrons and positrons incident on a single diamond crystal

    Science.gov (United States)

    Kirsebom, K.; Mikkelsen, U.; Uggerhøj, E.; Elsener, K.; Ballestrero, S.; Sona, P.; Connell, S. H.; Sellschop, J. P. F.; Vilakazi, Z. Z.

    2001-04-01

    A few years ago the CERN NA-43 collaboration installed an upgraded detector system which allows a detailed analysis of the particle motion before, during and after penetration of a crystal. Also, essentially perfect diamond crystals were produced by the collaborators from Schonland Research Centre. These facts have led to new and very detailed investigations of QED-processes in strong crystalline fields. Along axial directions the radiation emission is enhanced by more than two orders of magnitude. For incidence on a 0.7 mm thick diamond crystal of well-aligned 149 GeV electrons, 35% give rise to a high energy photon peak at ≃120 GeV. For 243 GeV electrons and ≃200 GeV photons, this number decreases to 25% - which may be an indication of quantum suppression. Different measurements of the photon multiplicities show that in most cases positrons and electrons emit equal number of photons. The dramatic radiation emission leads to a strong reduction in transverse energy and all electrons incident within the critical angle are captured to high lying channeling states and exit at channeling angles corresponding to their final energy - a completely new result for negatively charged particles. For the first time, we present an analysis where the photon is used as a `messenger' for the transverse energy of the electron during the formation time and we conclude that the more energetic photons are created closer to the string and emitted in the axial direction - in contrast to earlier calculations using the Dirac equation. The strongly enhanced radiation emission leads to angular cooling for electrons but angular heating for positrons and we show that at higher electron energies the cooling becomes stronger as expected from theory. For electrons, the radiative cooling gives rise to a capture of above-barrier particles into the channeled beam. The total radiative energy loss is shown as not to follow the γ2-law expected from classical electrodynamics, but turns over

  10. New Synthetic and Assembly Methodology for Guiding Nanomaterial Assembly with High Fidelity into 1D Clusters and 3D Crystals Using Biomimetic Interactions

    Science.gov (United States)

    2015-03-26

    AFRL-OSR-VA-TR-2015-0105 NEW SYNTHETIC AND ASSEMBLY METHODOLOGY FOR GUIDING NANOMATERIAL ASSEMBLY WITH HI Mathew Maye SYRACUSE UNIVERSITY Final...2010 - 12/31/2014 New Synthetic and Assembly Methodology for Guiding Nanomaterial Assembly with High Fidelity into ID cluster and 3D Crystals Using...1) Principle Investigator Name: Mathew M. Maye (2) Grant/Contract Title: PECASE: New Synthetic and Assembly Methodology for Guiding Nanomaterial

  11. Assessing the quality of x-ray optic surfaces of Si crystals cut by diamond-wire and rotating-blade sawing techniques.

    Energy Technology Data Exchange (ETDEWEB)

    Wieczorek, M.; Huang, X.; Maj, J.; Conley, R.; Qian, J.; Macrander, A.; Christensen, C.; Hodsden, J.; Khachatryan, R. (X-Ray Science Division); (Diamondwire Technology)

    2008-01-01

    The next generation of X-ray diffraction optics will benefit from crystal surfaces with very high quality (extremely flat and strain-free), but knowledge on how to achieve such surfaces and how surface imperfections affect the diffraction properties is sparse in the literature. As a first step to initialize a systematic study on this topic, we evaluate in this paper the surface quality of two Si (111) wafers cut by a diamond-wire saw and a rotating blade saw, respectively. We concentrate on revealing lattice strains induced by the two cutting methods and on strain evolution during three rounds of chemical etching (without polishing). The measurements also provide some important clues as to how surface roughness affects rocking curve widths and other diffraction properties.

  12. The crystal structure of synthetic kutinaite, Cu14Ag6As7

    DEFF Research Database (Denmark)

    Karanovic, Ljiljana; Poleti, Dejan; Makovicky, Emil;

    2002-01-01

    kutinaite, X-ray diffraction, powder method, crystal structure, icosahedral alloy, arsenide, metal clusters......kutinaite, X-ray diffraction, powder method, crystal structure, icosahedral alloy, arsenide, metal clusters...

  13. 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.

  14. 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.

  15. UV-Raman and NMR spectroscopic studies on the crystallization of zeolite A and a new synthetic route.

    Science.gov (United States)

    Ren, Limin; Li, Caijin; Fan, Fengtao; Guo, Qiang; Liang, Desheng; Feng, Zhaochi; Li, Can; Li, Shougui; Xiao, Feng-Shou

    2011-05-23

    UV-Raman and NMR spectroscopy, combined with other techniques, have been used to characterize crystallization of zeolite A. In situ UV-Raman spectroscopy shows that the starting gel for crystallization of zeolite A contains a lot of four-ring (4R) building units and the appearance of six-ring (6R) building blocks is the signal for crystal formation. (29)Si NMR spectroscopy results suggest that the starting gel is double four-ring (D4R) rich and during crystallization of zeolite A both α and β cages appear. (27)Al NMR spectroscopy results indicate the absence of Al (2Si) species in the starting gel, suggesting the absence of single 4R building units in the starting gel. Furthermore, composition analysis of both solid and liquid samples shows that the solid rather than liquid phase predominates for the crystallization of zeolite A. Therefore, it is proposed that the crystallization of zeolite A mainly occurs in the solid phase by self-assembly or rearrangement starting from the zeolite building units mainly consisting of D4R. The essential role of D4R is directly confirmed by successful conversion from a solution of D4R to zeolite A in the presence of NaCl, and the importance of solid phase is reasonably demonstrated by the successful synthesis of zeolite A from a dry aluminosilicate gel. By considering that the solid phase has a major contribution to crystallization, a novel route was designed to synthesizing zeolite A from the raw materials water glass (Na(2)SiO(3) in aqueous solution) and NaAlO(2), without additional water and NaOH; this route not only simplifies synthetic procedures, but reduces water consumption. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Mechanism of diamond-to-graphite transformation at diamond-stable conditions

    Institute of Scientific and Technical Information of China (English)

    ZANG ChuangYi; CHEN XiaoZhou; HU Qiang; MA HongAn; JIAXiaoPeng

    2009-01-01

    The diamond-to-graphite transformation at diamond-stable conditions is studied by temperature gradient method (TGM) under high pressure and high temperature (HPHT), although it is unreasonable from the view of thermodynamic considerations. It is found that, at diamond-stable conditions, for example, at 5.5 GPa and 1550 K, with fine diamond grits as carbon source and NiMnCo alloy as metal solvent assisted, not only large diamond crystals, but metastable regrown graphite crystals would be grown by layer growth mechanism, and the abundance of carbon source in the higher temperature region is indispensable for the presence of metastable regrown graphite crystals. From this transformation, it is concluded that, with metal solvent assisted, although the mechanism of crystal growth could be understood by the macro-mechanism of solubility difference between diamond and graphite in metal solvents, from the point of micro-mechanism, the minimum growth units for diamond or graphite crystals should be at atomic level and unrelated to the kinds of carbon source (diamond or graphite), which could be accumulated free-selectively on the graphite with sp2Tr or diamond crystals with sp3 bond structure.

  17. Electric transport measurements on micro-structured CePt2In7 single crystals in a diamond anvil cell

    Science.gov (United States)

    Kanter, J.; Moll, P.; Ronning, F.; Bauer, E.; Tobash, P.; Thompson, J.; Batlogg, B.

    2012-02-01

    We report Shubnikov--de Haas and resistivity measurements of CePt2In7 samples under hydrostatic pressures using a diamond anvil cell. CePt2In7 belongs to the CemMnIn3m+2n heavy fermion family. Compared to the CeMIn5 members of this group, the structure of CePt2In7 has a more two dimensional character, but also exhibits an antiferromagnetically ordered and a superconducting phase. Upon increasing pressure the AFM order is suppressed with the N'eel temperature extrapolating to a quantum critical point. The fluctuations associated with the QCP are thought to stabilize the unconventional superconducting phase. To investigate the weight of the different scattering channels the anisotropy of the resistivity above the N'eel temperature was measured for various applied pressures. Shubnikov--de Haas measurements were conducted to deduce the changes in the effective electron masses in the AFM and superconducting phases under applied hydrostatic pressure. To this end we developed a method to conduct four terminal resistance measurements on micro-structured samples inside a diamond anvil cell.

  18. Latest Progress in Synthetic Inlay Structured Diamond Coatings%镶嵌结构界面金刚石涂层研究进展

    Institute of Scientific and Technical Information of China (English)

    邱万奇; 陈星婷; 刘仲武; 钟喜春; 余红雅; 曾德长

    2011-01-01

    The latest progress in the fields of synthesis of the plane and inlay structured diamond coatings, the adhesion strength and microstructures at the interface of the coating and substrate, and the mechanisms responsible for cracking and failures under bending stress was tentatively reviewed in a thought-provoking way. The discussions centered on the state-of-the-art synthesis technologies of the inlay structured diamond coatings, the intensively studied subjects of basic interest , and the development trends. The preliminary results show that the inlay structured interlayer significantly enhances the adhesion strength at the interface of the inlay structured diamond coatings and the substrate.%对平面结构和镶嵌结构界面金刚石涂层的界面结构特点、受弯曲应力应变时的失效方式进行了分析,指出镶嵌结构界面金刚石涂层是提高膜/基体结合力的有效方法;综述了镶嵌结构界面金刚石涂层的国内外研究现状,并指出了今后镶嵌结构界面金刚石涂层的发展方向.

  19. 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

  20. Sub-band gap photo-enhanced secondary electron emission from high-purity single-crystal chemical-vapor-deposited diamond

    Science.gov (United States)

    Yater, J. E.; Shaw, J. L.; Pate, B. B.; Feygelson, T. I.

    2016-02-01

    Secondary-electron-emission (SEE) current measured from high-purity, single-crystal (100) chemical-vapor-deposited diamond is found to increase when sub-band gap (3.06 eV) photons are incident on the hydrogenated surface. Although the light does not produce photoemission directly, the SEE current increases by more than a factor of 2 before saturating with increasing laser power. In energy distribution curves (EDCs), the emission peak shows a corresponding increase in intensity with increasing laser power. However, the emission-onset energy in the EDCs remains constant, indicating that the bands are pinned at the surface. On the other hand, changes are observed on the high-energy side of the distribution as the laser power increases, with a well-defined shoulder becoming more pronounced. From an analysis of this feature in the EDCs, it is deduced that upward band bending is present in the near-surface region during the SEE measurements and this band bending suppresses the SEE yield. However, sub-band gap photon illumination reduces the band bending and thereby increases the SEE current. Because the bands are pinned at the surface, we conclude that the changes in the band levels occur below the surface in the electron transport region. Sample heating produces similar effects as observed with sub-band gap photon illumination, namely, an increase in SEE current and a reduction in band bending. However, the upward band bending is not fully removed by either increasing laser power or temperature, and a minimum band bending of ˜0.8 eV is established in both cases. The sub-band gap photo-excitation mechanism is under further investigation, although it appears likely at present that defect or gap states play a role in the photo-enhanced SEE process. In the meantime, the study demonstrates the ability of visible light to modify the electronic properties of diamond and enhance the emission capabilities, which may have potential impact for diamond-based vacuum electron

  1. 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

  2. Dependence of Growing High-Quality Gem Diamonds on Growth Rates by Temperature Gradient Method

    Institute of Scientific and Technical Information of China (English)

    ZANG Chuan-Yi; JIA Xiao-Peng; REN Guo-Zhong; WANG Xian-Cheng

    2004-01-01

    @@ Using the temperature gradient method under high pressure and high temperature, we investigate the dependence of growing high-quality gem diamond crystals on the growth rates. It is found that the lower the growth rate of gem diamond crystals, the larger the temperature range of growing high-quality gem diamond crystals, and the easier the control of temperature.

  3. 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.

  4. 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...

  5. 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

  6. Research of work stability of diamond detectors used in SCR DDIR

    Science.gov (United States)

    Ibragimov, R. F.; Tyurin, E. M.; Kadilin, V. V.; Kolyubin, V. A.; Zaharchenko, K. V.; Nedosekin, P. G.

    2016-02-01

    In this work we study influence of various factors on stability of ionizing radiation detectors installed in the cosmic ray spectrometer (SCR) based on diamond detectors of ionization radiation (DDIR). Diamond detectors for SCR are made of single crystals of synthetic diamond type IIa. Diamond detectors were studied successively in three different experiments. Checking detector stability with ambient temperature increased up to 70 degrees Celsius was the first experiment. At next we change the geometry of detector irradiation by rotating nuclear source around it and measuring changes in detector count rate. And last one experiment was about checking the phenomenon of polarization by prolonged detector irradiation by ionizing radiation of various types and energies. The study revealed the presence of the strong influence of the polarization effect on the work of diamond detectors for registration of ionizing particles with short mean free path (in our experiment they were the alfa-particles of 238Pu). In this work correspondence of the experimental results of the “rotation” the source around the detector with the data obtained by simulation in GEANT-4 was shown.

  7. Crystal structure of the new diamond-like semiconductor CuMn$_2$InSe$_4$

    Indian Academy of Sciences (India)

    G E DELGADO; V SAGREDO

    2016-12-01

    The crystal structure of the semiconductor compound CuMn$_2$InSe$_4$ was analysed using X-ray powder diffraction data. CuMn$_2$InSe$_4$ crystallizes, with a stannite structure, in the tetragonal space group I$\\bar{4}$2m (No. 121), $Z = 2$, with unit cell parameters $a = 5.8111(2) \\AA$, $c = 11.5739(8) \\AA$ and $V = 390.84(3) \\AA^#$. The refinement of 28 instrumental and structural parameters led to $R_{\\rm p} = 8.1$%, $R_{\\rm wp} = 10.5$%, $R_{\\rm exp} = 6.5$% and $S = 1.6,$ for 86 independent reflections.

  8. Isophthalate-Hydrazone 2D Zinc-Organic Framework: Crystal Structure, Selective Adsorption, and Tuning of Mechanochemical Synthetic Conditions.

    Science.gov (United States)

    Roztocki, Kornel; Jędrzejowski, Damian; Hodorowicz, Maciej; Senkovska, Irena; Kaskel, Stefan; Matoga, Dariusz

    2016-10-03

    A new layered mixed-linker metal-organic framework [Zn2(iso)2(pcih)2]n (MOF) built from isophthalate ions (iso(2-)) and 4-pyridinecarbaldehyde isonicotinoyl hydrazone (pcih) was prepared using both solution and mechanochemical methods. By use of the latter, the 2D MOF is obtained either in a one-mortar three-component grinding or on the way of a two-step mechanosynthesis. Tuning of mechanochemical synthetic conditions allowed us to identify both necessary and favorable factors for the solid-state formation of the MOF. Single-crystal X-ray diffraction reveals the presence of interdigitated layers in the ABAB arrangement and interlayer 0D cavities filled with guest molecules. Upon thermal activation, the dynamic framework exhibits stepwise and selective adsorption of CO2 over N2 as well as high-pressure H2 adsorption reaching maximum excess of 1.15 wt% at 77 K. The mechanochemical synthetic protocol is expanded to a few other interdigitated structures.

  9. Plasma test on industrial diamond powder in hydrogen and air for fracture strength study

    Science.gov (United States)

    Chary, Rohit Asuri Sudharshana

    Diamonds are the most precious material all over the world. Ever since their discovery, the desire for natural diamonds has been great; recently, the demand has steeply increased, leading to scarcity. For example, in 2010, diamonds worth $50 billion were marketed. This increased demand has led to discovering alternative sources to replace diamonds. The diamond, being the hardest material on earth, could be replaced with no other material except another diamond. Thus, the industrial or synthetic diamond was invented. Because of extreme hardness is one of diamond's properties, diamonds are used in cutting operations. The fracture strength of diamond is one of the crucial factors that determine its life time as a cutting tool. Glow discharge is one of the techniques used for plasma formation. The glow discharge process is conducted in a vacuum chamber by ionizing gas atoms. Ions penetrate into the atomic structure, ejecting a secondary electron. The objective of this study is to determine the change in fracture strength of industrial diamond powder before and after plasma treatment. This study focuses mainly on the change in crystal defects and crushing strength (CS) of industrial diamond powder after the penetration of hydrogen gas, air and hydrogen-air mixture ions into the sample powder. For this study, an industrial diamond powder sample of 100 carats weight, along with its average fracture strength value was received from Engis Corporation, Illinois. The sample was divided into parts, each weighing 10-12 carats. At the University of Nevada, Las Vegas (UNLV), a plasma test was conducted on six sample parts for a total of 16 hours on each part. The three gas types mentioned above were used during plasma tests, with the pressure in vacuum chamber between 200 mTorr and 2 Torr. The plasma test on four sample parts was in the presence of hydrogen-air mixture. The first sample had chamber pressures between 200 mTorr and 400 mTorr. The remaining three samples had chamber

  10. Optical properties of synthetic crystals of brushite (CaHPO 4·2H 2O)

    Science.gov (United States)

    Lundager Madsen, Hans E.

    2008-02-01

    The principal refractive indices of brushite (CaHPO 4·2H 2O) crystals for sodium light, 589 nm, have been determined by a combination of several methods: microscopic interferometry, retardation measurements with an Ehringhaus 6 λ compensator, and determination of the angle 2 V between optic axes from the measurements of extinction directions using a spindle stage and evaluating the data with the computer program EXCALIBRW. The following values were found: n α=1.54089, n β=1.54620, n γ=1.55191, and 2 V=88.2°. The standard deviations of the three indices lie in the range 7-8×10 -5. The results are regarded valuable in connection with studies of crystal growth kinetics in biological mineralization and related fields.

  11. Single-crystal X-ray diffraction study of synthetic sodium-hydronium jarosite

    Science.gov (United States)

    Najorka, Jens; Lewis, James M. T.; Spratt, John; Sephton, Mark A.

    2016-05-01

    Na-H3O jarosite was synthesized hydrothermally at 413 K for 8 days and investigated using single-crystal X-ray diffraction (XRD) and electron microprobe analysis (EMPA). The chemical composition of the studied crystal is [Na0.57(3) (H3O)0.36 (H2O)0.07]A Fe2.93(3) (SO4)2 (OH)5.70 (H2O)0.30, and Fe deficiency was confirmed by both EMPA and XRD analysis. The single-crystal XRD data were collected at 298 and 102 K, and crystal structures were refined in space group Roverline{3}m. The room-temperature data match structural trends of the jarosite group, which vary linearly with the c axis. The low-temperature structure at 102 K shows an anisotropic decrease in the unit cell parameters, with c and a decreasing by 0.45 and 0.03 %, respectively. Structural changes are mainly confined to the A site environment. Only minor changes occur in FeO6 and SO4 polyhedra. The structure responds upon cooling by increasing bond length distortion and by decreasing quadratic elongation of the large AO12 polyhedra. The structural parameters at low temperature follow very similar patterns to structural changes that correspond to compositional variation in the jarosite group, which is characterised by the flexibility of AO12 polyhedra and rigidity of Fe(OH)4O2-SO4 layers. The most flexible areas in the jarosite structure are localized at AO12 edges that are not shared with neighbouring FeO6 octahedra. Importantly, for the application of XRD in planetary settings, the temperature-related changes in jarosite can mimic compositional change.

  12. A novel synthetic route to freely adjust the crystal structures of Ni-P compounds

    Science.gov (United States)

    Xu, Hanghui; Lu, Shaoxiang; Ren, Lili

    2016-10-01

    Crystal-structure-controllable Ni-P compounds were synthesized using nickel chloride, nontoxic red phosphorus and polyethylene glycol. The hexagonal Ni2P and tetragonal Ni12P5 could be freely transformed via adjusting the amount of polyethylene glycol, and the mechanism of phase transformation was discussed. The catalytic performances of Ni-P compounds were promoted markedly with moderate quantity of PEG. However, excessive PEG will cover the active sites of catalysts and decrease the catalytic activity.

  13. Isolation of brassicasterol, its synthetic prodrug-crystal structure, stereochemistry and theoretical studies

    Science.gov (United States)

    Sethi, Arun; Prakash, Rohit; Srivastava, Sangeeta; Amandeep; Bishnoi, Abha; Singh, Ranvijay Pratap

    2014-07-01

    In the present study brassicasterol (1), was isolated from the chloroform extract of the flowers of Allamanda violacea and identified with the help of different spectroscopic techniques like 1H, 13C, 2D NMR (1H-1H COSY), IR, UV and mass spectrometry. A novel prodrug was synthesized by carrying out esterification of brassicasterol (1) with the well known drug naproxen using Steglich esterification to give 3β-(2-(6-methoxynaphthalene-2yl) propionoxy) 24 methyl cholest-5, 22-dien (2). Compounds 2 was subjected to single crystal X-ray diffraction technique and crystallized out in monoclinic form having P21 space group and stabilized by CH-π interactions. Structure and stereochemistry of compound 2 was established with the help of modern spectroscopic techniques like 1H NMR, IR, UV, mass spectrometry as well as with single crystal X-ray diffraction. Molecular geometry and vibrational frequencies of compounds 1 and 2 were calculated by density functional method (DFT/B3LYP) using 6-31G (d, p) basis set, bond parameters and IR frequencies were correlated with the experimental data. 1H and 13C chemical shifts of compound 1 and 1H chemical shifts of compound 2 were calculated with GIAO method and correlated with experimental data. Hyperconjugative interactions were studied with the help of natural bond order analysis (NBO). Electronic properties of both the compounds such as HOMO-LUMO energies were measured with the help of time dependent DFT method.

  14. 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.

  15. A Mathematica package for calculation of planar channeling radiation spectra of relativistic electrons channeled in a diamond-structure single crystal (quantum approach)

    Science.gov (United States)

    Azadegan, B.

    2013-03-01

    The presented Mathematica code is an efficient tool for simulation of planar channeling radiation spectra of relativistic electrons channeled along major crystallographic planes of a diamond-structure single crystal. The program is based on the quantum theory of channeling radiation which has been successfully applied to study planar channeling at electron energies between 10 and 100 MeV. Continuum potentials for different planes of diamond, silicon and germanium single crystals are calculated using the Doyle-Turner approximation to the atomic scattering factor and taking thermal vibrations of the crystal atoms into account. Numerical methods are applied to solve the one-dimensional Schrödinger equation. The code is designed to calculate the electron wave functions, transverse electron states in the planar continuum potential, transition energies, line widths of channeling radiation and depth dependencies of the population of quantum states. Finally the spectral distribution of spontaneously emitted channeling radiation is obtained. The simulation of radiation spectra considerably facilitates the interpretation of experimental data. Catalog identifier: AEOH_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEOH_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 446 No. of bytes in distributed program, including test data, etc.: 209805 Distribution format: tar.gz Programming language: Mathematica. Computer: Platforms on which Mathematica is available. Operating system: Operating systems on which Mathematica is available. RAM: 1 MB Classification: 7.10. Nature of problem: Planar channeling radiation is emitted by relativistic charged particles during traversing a single crystal in direction parallel to a crystallographic plane. Channeling is modeled as the motion

  16. 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.

  17. Fine Structural and Carbon Source Analysis for Diamond Crystal Growth using an Fe-Ni-C System at High Pressure and High Temperature

    Institute of Scientific and Technical Information of China (English)

    FAN Xiao-Hong; XU Bin; NIU Zhen; ZHAI Tong-Guang; TIAN Bin

    2012-01-01

    Diamond is synthesized in an Fe-Ni-C system at high pressure and high temperature,the C sp3 content profile through different thicknesses of interface between diamond and the catalyst film is measured by using electron energy loss spectroscopy.It is found that the Csp3 content varies from 87.33% to 78.15% when the measured position is located at the inner face near the diamond and then changes to 6 μm further away.Transmission electron microscope examinations show that there are different phases in the interface,such as Fe3C,γ-(Fe,Ni),and graphite,but the graphite phase diminishes gradually towards the inner face of the interface.These results profoundly indicate that the carbon atoms,required for diamond growth,could only come from the carbon-rich phase,Fe3C,but not directly from the graphite.It is possible that carbon atoms from the graphite in the interface first react with Fe atoms to produce carbide Fe3 C during diamond synthesis at high pressure and high temperature.The Fe3 C finally decomposes into carbon atoms with the sp3 electron state at the interface to form the diamond.%Diamond is synthesized in an Fe-Ni-C system at high pressure and high temperature, the Csp3 content profile through different thicknesses of interface between diamond and the catalyst film is measured by using electron energy loss spectroscopy. It is found that the Csp3 content varies from 87.33% to 78.15% when the measured position is located at the inner face near the diamond and then changes to 6μm further away. Transmission electron microscope examinations show that there are different phases in the interface, such as Fe3 C1 γ-(Fe,Ni), and graphite, but the graphite phase diminishes gradually towards the inner face of the interface. These results profoundly indicate that the carbon atoms, required for diamond growth, could only come from the carbon-rich phase, Fe3C, but not directly from the graphite. It is possible that carbon atoms from the graphite in the interface first

  18. DiamondViewTM在宝石检测中的应用%On the application of DiamondViewTM in gem identiifcation

    Institute of Scientific and Technical Information of China (English)

    涂彩; 汤红云; 陆晓颖

    2014-01-01

    通过对天然、合成钻石,充填处理祖母绿及合成红宝石的检测实验,证明了DiamondViewTM在宝石检测中的多样化应用。实验结果表明,DiamondViewTM还可以直观快速地观察到祖母绿裂隙中的充填物;同时也可以用来检测例如焰熔法合成红宝石等其他合成宝石,是一台比较直观方便的珠宝检测辅助仪器。%This article test natural, synthetic diamonds, filled emeralds and synthetic ruby using DiamondViewTM, and prove that DiamondViewTM is a useful tool for gem identification. DiamondViewTM is always used for identifying synthetic diamonds by fluorescence image which can show the structural characteristics of growth of diamond. But in our results, DiamondViewTM can also observe fillers in fissure of emerald quickly and directly;and also, DiamondViewTM can be used to identify other synthetic gemstones, like synthetic ruby by flame fusion method. These prove that DiamondViewTM is a more intuitive and convenient instrumentation for gem identification.

  19. 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.

  20. Evaluating Multidimensional Queries by Diamond Dicing

    CERN Document Server

    Webb, Hazel; Lemire, Daniel

    2010-01-01

    Queries that constrain multiple dimensions simultaneously are difficult to express and compute efficiently in both Structured Query Language (SQL) and multidimensional languages. We introduce the diamond cube operator to facilitate the expression of one such class of multidimensional query. We have developed, implemented and tested algorithms to compute diamonds on both real and synthetic large data sets. We show that our custom implementation is more than twenty-five times faster, on a large data set, than popular database engines.

  1. Crystal Structures of the Nuclear Receptor, Liver Receptor Homolog 1, Bound to Synthetic Agonists.

    Science.gov (United States)

    Mays, Suzanne G; Okafor, C Denise; Whitby, Richard J; Goswami, Devrishi; Stec, Józef; Flynn, Autumn R; Dugan, Michael C; Jui, Nathan T; Griffin, Patrick R; Ortlund, Eric A

    2016-12-02

    Liver receptor homolog 1 (NR5A2, LRH-1) is an orphan nuclear hormone receptor that regulates diverse biological processes, including metabolism, proliferation, and the resolution of endoplasmic reticulum stress. Although preclinical and cellular studies demonstrate that LRH-1 has great potential as a therapeutic target for metabolic diseases and cancer, development of LRH-1 modulators has been difficult. Recently, systematic modifications to one of the few known chemical scaffolds capable of activating LRH-1 failed to improve efficacy substantially. Moreover, mechanisms through which LRH-1 is activated by synthetic ligands are entirely unknown. Here, we use x-ray crystallography and other structural methods to explore conformational changes and receptor-ligand interactions associated with LRH-1 activation by a set of related agonists. Unlike phospholipid LRH-1 ligands, these agonists bind deep in the pocket and do not interact with residues near the mouth nor do they expand the pocket like phospholipids. Unexpectedly, two closely related agonists with similar efficacies (GSK8470 and RJW100) exhibit completely different binding modes. The dramatic repositioning is influenced by a differential ability to establish stable face-to-face π-π-stacking with the LRH-1 residue His-390, as well as by a novel polar interaction mediated by the RJW100 hydroxyl group. The differing binding modes result in distinct mechanisms of action for the two agonists. Finally, we identify a network of conserved water molecules near the ligand-binding site that are important for activation by both agonists. This work reveals a previously unappreciated complexity associated with LRH-1 agonist development and offers insights into rational design strategies.

  2. Facile Synthetic Method and Crystal Structure of 2, 3, 3', 4'-Biphenyltetracarboxylic Dianhydride

    Institute of Scientific and Technical Information of China (English)

    YI Shi-xu; GAO Guo-wei; YANG Mei-jia; CHEN Hua; WU Di-feng; MEN Jian

    2012-01-01

    A facile method for the synthesis of 2,3,3',4'-biphenyltetracarboxylic dianhydride(a-BPDA)was reported,which comprises the steps of the dehalogenative coupling of dimethyl 4-chlorophthalate(4-DMCP)and dimethyl3-chlorophthalate(3-DMCP)catalyzed by low-cost(Ph3P)2NiCl2,the hydrolysis of tetra-ester and the dehydration of tetra-acid.In contrast to the conventional methods,this method has the advantage of low cost,convenient manipulation,available condition,high purity and good overall yield.Moreover,the single crystal structure of a-BPDA was analyzed by X-ray diffraction method.The X-ray data suggest that a-BPDA is a rigid,non-coplanar and non-linear structure.It contains three crystallographically independent molecules,in which the dihedral angles of the two linked phenyl rings are 44.75(4)°,46.37(3)° and 42.32(3)°,respectively.The title molecule is governed by a stronger intermolecular interaction in contrast to van der Waals interaction because of the special positions of anhydride groups.

  3. 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.

  4. High-pressure-high-temperature treatment of natural diamonds

    CERN Document Server

    Royen, J V

    2002-01-01

    The results are reported of high-pressure-high-temperature (HPHT) treatment experiments on natural diamonds of different origins and with different impurity contents. The diamonds are annealed in a temperature range up to 2000 sup o C at stabilizing pressures up to 7 GPa. The evolution is studied of different defects in the diamond crystal lattice. The influence of substitutional nitrogen atoms, plastic deformation and the combination of these is discussed. Diamonds are characterized at room and liquid nitrogen temperature using UV-visible spectrophotometry, Fourier transform infrared spectrophotometry and photoluminescence spectrometry. The economic implications of diamond HPHT treatments are discussed.

  5. 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...

  6. 山东金刚石晶体中氮片晶的分布特征及其表面微形貌%Distribution Characteristics and Surface Microtopography of Nitrogen Platelets in Diamond Crystals from Shandong Province,China

    Institute of Scientific and Technical Information of China (English)

    张健; 陈华; 陆太进; 丘志力; 魏然

    2011-01-01

    In order to study the distribution characteristics of nitrogen platelets in diamond crystals from Shandong Province,China,116 pieces of gem quality diamond crystal samples are investigated by using FTIR.The surface microstructures related to the nitrogen platelets are observed by differential interference microscope.The results show that 80.2% of the diamond samples contain nitrogen platelets.The stripe-like etch figures parallel to directions on {111} planes are discovered on the surfaces of several brown octahedral diamond samples.These etch figures lie parallel to each other and vary in size.The microanalysis of the {111} planes show that there are stronger IR absorption peaks at 1359-1375cm-1 in the diamond samples,revealing the existence of huge quantities of nitrogen platelets.Judging from their appearances and IR spectra,the formation of the stripe-like etch figures parallel to directions on {111} planes may result from selective etching of the platelets.%为研究山东蒙阴金伯利岩型金刚石晶体中氮片晶的分布特征,采用红外光谱仪对116粒宝石级金刚石晶体样品中的氮片晶进行分析,并采用微分干涉显微镜观察氮片晶在金刚石表面所具有的物理化学性质及其表面微细结构。结果表明,80.2%的金刚石样品中具有氮片晶;在个别浅褐色、八面体金刚石样品{111}面上观察到平行于[100]晶带方向的长条状蚀像,这些蚀像相互平行,大小不等。显微红外光谱对具长条状蚀像的金刚石样品{111}面的测试结果表明,该类晶体均具有较强的氮片晶的吸收峰(1359~1375cm-1)。综合浅褐色、八面体金刚石样品的红外光谱及其表面微形貌特征,推测长条状蚀像是由氮片晶的出露点受优先选择性腐蚀而致。

  7. 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.

  8. 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

  9. Neutron emission spectroscopy of DT plasmas at enhanced energy resolution with diamond detectors

    Science.gov (United States)

    Giacomelli, L.; Nocente, M.; Rebai, M.; Rigamonti, D.; Milocco, A.; Tardocchi, M.; Chen, Z. J.; Du, T. F.; Fan, T. S.; Hu, Z. M.; Peng, X. Y.; Hjalmarsson, A.; Gorini, G.

    2016-11-01

    This work presents measurements done at the Peking University Van de Graaff neutron source of the response of single crystal synthetic diamond (SD) detectors to quasi-monoenergetic neutrons of 14-20 MeV. The results show an energy resolution of 1% for incoming 20 MeV neutrons, which, together with 1% detection efficiency, opens up to new prospects for fast ion physics studies in high performance nuclear fusion devices such as SD neutron spectrometry of deuterium-tritium plasmas heated by neutral beam injection.

  10. Crystallization and preliminary X-ray diffraction studies of a toxic phospholipase A2 from the venom of Vipera ammodytes meridionalis complexed to a synthetic inhibitor.

    Science.gov (United States)

    Georgieva, Dessislava Nikolova; Rypniewski, Wojciech; Perbandt, Markus; Jain, Mahendra; Genov, Nicolay; Betzel, Christian

    2003-08-21

    A toxic phospholipase A(2) (PLA(2)) is isolated from the neurotoxic complex Vipoxin, the major lethal component of the venom of Vipera ammodytes meridionalis. The enzyme is complexed to the synthetic inhibitor elaidoylamide and crystallized. The crystals belong to the space group P2(1)2(1)2(1), with unit cell dimensions a=46.57 A, b=82.68 A, c=119.47 A and beta=90 degrees. Initial diffraction data to 3.3 A resolution are collected.

  11. 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.

  12. Investigation of planar channeling radiation on diamond and quartz crystals at electron energies between 14 and 34 MeV and probing the influence of ultrasonic waves on channeling radiation

    Energy Technology Data Exchange (ETDEWEB)

    Azadegan, B.

    2007-11-15

    Measurements of planar channeling radiation (CR) have been performed at the electron beam of ELBE within an energy range between 14 and 34 MeV and for thicknesses of the diamond crystals between 42.5 and 500 {mu}m. Absolute CR photon yields have for the first time been obtained for the above given ranges of electron energy and crystal thickness. The square-root dependence of the planar CR photon yield on the thickness of diamond crystals has been confirmed. A systematic quantitative investigation of the influence of the crystal thickness on the CR line shape has for the first time been performed. The mean-squared multiple-scattering angle effective for planar CR observed in forward direction has been found to be weaker as assumed from scattering in amorphous targets. Scaling laws deduced from the measured CR data are of advantage for the operation of a CR source. The second part of this thesis deals with the possibility of stimulation of CR emission by means of ultrasonic vibrations excited in a piezoelectric single crystal. Since the knowledge of the CR spectra generated on undisturbed quartz crystals is a necessary precondition for some investigation of the influence of US, planar CR has for the first time been measured at medium electron energies for a variety of planes in quartz. As a consequence of the hexagonal structure of this crystal, relative intense CR could be registered even out of planes with indices larger than one. On the base of the non-linear optics method, occupation functions and spectral distributions of planar CR have been calculated for channeling of 20 MeV electrons in the (01 anti 15) plane of a 20 {mu}m thick quartz crystal at resonant influence of ultrasound (US). The resonance frequencies have been deduced from the measurements of CR spectra performed on quartz. First experimental investigations of the influence of US on CR started at ELBE aimed at the study of the effect of non-resonant ultrasonic vibrations excited in a 500 {mu}m thick

  13. An Analysis of the Retention of a Diamond Particle in a Metallic Matrix after Hot Pressing

    Directory of Open Access Journals (Sweden)

    Borowiecka-Jamrozek J.

    2017-03-01

    Full Text Available This paper deals with computer modelling of the retention of a synthetic diamond particle in a metallic matrix produced by powder metallurgy. The analyzed sintered powders can be used as matrices for diamond impregnated tools. First, the behaviour of sintered cobalt powder was analyzed. The model of a diamond particle embedded in a metallic matrix was created using Abaqus software. The preliminary analysis was performed to determine the mechanical parameters that are independent of the shape of the crystal. The calculation results were compared with the experimental data. Next, sintered specimens obtained from two commercially available powder mixtures were studied. The aim of the investigations was to determine the influence of the mechanical and thermal parameters of the matrix materials on their retentive properties. The analysis indicated the mechanical parameters that are responsible for the retention of diamond particles in a matrix. These mechanical variables have been: the elastic energy of particle, the elastic energy of matrix and the radius of plastic zone around particle.

  14. Advanced Bonded Diamond for Optical Applications

    Science.gov (United States)

    2011-11-28

    demonstrates a doublet structure. As we know , diamond crystal will give a typical Raman peak at 1332 (1/cm). If the diamond grain is under tensile stress, the...1617nm to 1645 nm. Illuaiiri«nt: MHITI Htdiu»: AIB Sub-sttftt-e: GLASS Ixlt: CLASS D«tact or : U>1AL Angle: 0.0 (dag) Mf* MUt : 1430.0

  15. 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.

  16. Response measurement of single-crystal chemical vapor deposition diamond radiation detector for intense X-rays aiming at neutron bang-time and neutron burn-history measurement on an inertial confinement fusion with fast ignition

    Energy Technology Data Exchange (ETDEWEB)

    Shimaoka, T., E-mail: t.shimaoka@eng.hokudai.ac.jp; Kaneko, J. H.; Tsubota, M. [Graduate School of Engineering, Hokkaido University, Sapporo 060-8628 (Japan); Arikawa, Y.; Nagai, T.; Kojima, S.; Abe, Y.; Sakata, S.; Fujioka, S.; Nakai, M.; Shiraga, H.; Azechi, H. [Osaka University, 2-6 Yamada-Oka, Suita, Osaka 565-0871 (Japan); Isobe, M. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292 (Japan); Sato, Y. [The Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Chayahara, A.; Umezawa, H.; Shikata, S. [Diamond Research Laboratory, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577 (Japan)

    2015-05-15

    A neutron bang time and burn history monitor in inertial confinement fusion with fast ignition are necessary for plasma diagnostics. In the FIREX project, however, no detector attained those capabilities because high-intensity X-rays accompanied fast electrons used for plasma heating. To solve this problem, single-crystal CVD diamond was grown and fabricated into a radiation detector. The detector, which had excellent charge transportation property, was tested to obtain a response function for intense X-rays. The applicability for neutron bang time and burn history monitor was verified experimentally. Charge collection efficiency of 99.5% ± 0.8% and 97.1% ± 1.4% for holes and electrons were obtained using 5.486 MeV alpha particles. The drift velocity at electric field which saturates charge collection efficiency was 1.1 ± 0.4 × 10{sup 7} cm/s and 1.0 ± 0.3 × 10{sup 7} cm/s for holes and electrons. Fast response of several ns pulse width for intense X-ray was obtained at the GEKKO XII experiment, which is sufficiently fast for ToF measurements to obtain a neutron signal separately from X-rays. Based on these results, we confirmed that the single-crystal CVD diamond detector obtained neutron signal with good S/N under ion temperature 0.5–1 keV and neutron yield of more than 10{sup 9} neutrons/shot.

  17. Synthesis and electrical prop erties study of Ib typ e diamond single crystal co-dop ed with b oron and hydrogen under HPHT conditions%硼氢协同掺杂Ib型金刚石大单晶的高温高压合成与电学性能研究∗

    Institute of Scientific and Technical Information of China (English)

    李勇; 李宗宝; 宋谋胜; 王应; 贾晓鹏; 马红安

    2016-01-01

    Diamond is well known for its excellent properties, such as its hardness, high thermal conductivity, high electron and hole mobility, high breakdown field strength and large band gap (5.4 eV), which has been extensively used in many fields. However, its application in semiconductor area needs to be further understood, because it is irreplaceable by conventional semiconductor materials, especially in the extreme working conditions. In order to obtain diamond semiconductor with excellent electrical performances, diamond crystals co-doped with boron (B) and hydrogen (H) are synthesized in an FeNi-C system by temperature gradient growth at pressure 6.0 GPa and temperature 1600 K. Fourier infrared spectra measurements displayed that H is the formation of sp3 CH2-antisymmetric and sp3 -CH2-symmetric vibrations in the obtained diamond. Furthermore, the corresponding absorption peaks of H element are located at 2920 cm−1 and 2850 cm−1, respectively. Hall effects measurements demonstrated that the co-doped diamond exhibited that p-type material semiconductor performance, and the conductivity of the co-doped diamond is significantly enhanced comparing tocompared with the conductivity of the B-doping diamond. The results indicated that the Hall mobility mobilities is nearly equivalent between B-doped and co-doped diamond crystals are nearly equivalent, while the concentrations of the carriers and conductivity of the co-doped diamonds are higher than those of the B-doped diamond crystals. It is also noticed that the nitrogen concentration of the co-doped diamond decreases obviously, when the H and B are introduced into the diamond structure. Additionally, the change of the conductivity is investigated by first-principles calculation. In the B-doping diamond, two impurity levels are located in the forbidden band with small gaps. These impurity states above the Fermi level can trap the photo-excited electrons, while those below Fermi level can trap the photo

  18. Synthesis, Crystal Structures, and DFT Calculations of Three New Cyano(phenylsulfonylindoles and a Key Synthetic Precursor Compound

    Directory of Open Access Journals (Sweden)

    William L. Montgomery

    2015-09-01

    Full Text Available Three cyano-1-(phenylsulfonylindole derivatives, 3-cyano-1-(phenylsulfonyl indole, (I, 2-cyano-1-(phenylsulfonylindole, (II, and 2,3-dicyano-1-(phenylsulfonyl indole, (III, and a key synthetic precursor 1-(phenylsulfonyl-1-(1,1-dimethylethyl indole-3-carboxamide, (IV, have been synthesized and their structures determined by single crystal X-ray crystallography. (I, C15H10N2O2S, is orthorhombic with space group P 212121 and cell constants: a = 4.9459(3 Å, b = 10.5401(7 Å, c = 25.0813(14 Å, V = 1307.50(14 Å3 and Z = 4. (II, C15H10N2O2S, is monoclinic with space group C 2/c and cell constants: a = 18.062(2 Å, b = 11.293(2 Å, c = 15.922(3 Å, α = 90°, β = 124.49(2°, g = 90°, V = 2676.7 Å3 and Z = 8. (III, C16H9N3O2S, is triclinic with space group P-1 and cell constants: a = 8.1986(8 Å, b = 9.6381(11 Å, c = 9.8113(5 Å, α = 95.053(6°, β = 101.441(6°, g = 108.071(9°, V = 713.02(11 Å3 and Z = 2. (IV, C19H20N2O3S, is orthorhombic with space group P ccn and cell constants: a = 13.7605(8 Å, b = 27.3177(14 Å, c = 9.7584(6 Å, α = 90°, β = 90°, g =90°, V = 3668.2(4 Å3 and Z = 8. All four compounds have the same indole nitrogen phenylsulfonyl substituent and (I, (II, and (III are nitrile derivatives. (IV is a tert-butylamide. In the crystals, the dihedral angle between the mean planes of the indole and phenylsulfonyl groups are 85.4(2° (I, 87.2(7° (II, 75.1(7° (III, and 88.6(2° (IV, respectively. Additionally, DFT geometry-optimized molecular orbital calculations were performed and frontier molecular orbitals of each compound are displayed. Correlation between the calculated molecular orbital energies (eV for the surfaces of the frontier molecular orbitals to the electronic excitation transitions from the absorption spectra of each compound has been proposed.

  19. Diamond Field Emission Source using Transfer Mold Technique Prepared by Diamond Powder Seeding

    Science.gov (United States)

    Tezuka, Sachiaki; Matsuba, Yohei; Takahashi, Kohro

    Diamond thin films fabricated by MPCVD (microwave plasma chemical vapor deposition) are available for use as a field emitter material, because of its high mechanical quality, thermal conductivity, chemical stability, environmental tolerance, and NEA (negative electron affinity). Diode and triode emitter arrays using P-doped polycrystalline diamond were manufactured on a SiO2/Si(100) substrate with reverse pyramids formed by the transfer mold technique. As the diamond nucleation process, spin-coat seeding with pure diamond powder dispersed in isoamyl acetate has been introduced in place of the bias method. SEM (scanning electron microscopy) images and Raman spectroscopy indicate that the crystal quality of the diamond thin film fabricated by spin-coat seeding is superior to that fabricated by the bias method. The diamond crystal completely grew on top of the diode emitter by the US (ultrasonic) treatment in a diamond powder solution before spin-coat seeding. The tip radius was smaller than 50 nm. The beginning voltage of the emission of the diode emitter is 3 V after the DC glow discharge treatment in H2, which is lower than that of an emitter array fabricated by the bias method, 40 V. On the other hand, the emission of the diamond triode emitter starts at a gate voltage of only 0.5 V, and the emission current of 50∼60 mA is obtained at a gate voltage of 2 V.

  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. A Review on the Low-Dimensional and Hybridized Nanostructured Diamond Films

    Directory of Open Access Journals (Sweden)

    Hongdong Li

    2015-01-01

    Full Text Available In the last decade, besides the breakthrough of high-rate growth of chemical vapor deposited single-crystal diamonds, numerous nanostructured diamond films have been rapidly developed in the research fields of the diamond-based sciences and industrial applications. The low-dimensional diamonds of two-dimensional atomic-thick nanofilms and nanostructural diamond on the surface of bulk diamond films have been theoretically and experimentally investigated. In addition, the diamond-related hybrid nanostructures of n-type oxide/p-type diamond and n-type nitride/p-type diamond, having high performance physical and chemical properties, are proposed for further applications. In this review, we first briefly introduce the three categories of diamond nanostructures and then outline the current advances in these topics, including their design, fabrication, characterization, and properties. Finally, we address the remaining challenges in the research field and the future activities.

  2. Diamond particle detectors systems in high energy physics

    CERN Document Server

    Gan, Kock Kiam

    2015-01-01

    The measurement of luminosity at the Large Hadron Collider (LHC) using diamond detect or s has matured from devices based on a rather large pads to highly granular pixelated device s . The ATLAS experiment has recently installed a diamond pixel detector, the Diamond Beam Monitor (DBM), to measure the luminosity in the upgraded LHC with higher instantaneous luminosity. Polycrystalline diamonds were used to fabricate the diamond pixel modules. The design , production, and test beam result s are described. CMS also has a similar plan to construct a diamond based luminosity monitor, the Pixel Luminos ity Telescope s (PLT) . In a pilot run using single crystal diamond, the pulse height was found to depend on the luminosity . Consequently the collaboration decided to use silicon instead due to time constrain ts .

  3. Effect of Regrown Graphite on the Growth of Large Gem Diamonds by Temperature Gradient Method

    Institute of Scientific and Technical Information of China (English)

    ZANG Chuan-Yi; JIA Xiao-Peng; MA Hong-An; TIAN Yu; XIAO Hong-Yu

    2005-01-01

    @@ Generally, when growing high-quality large gem diamond crystals by temperature gradient method under high pressure and high temperature, the crystal growth rate is only determined by the temperature gradient. However,we find that the seed crystal cannot completely absorb all the diffused carbon sources, when growing gem diamonds under a higher temperature gradient. Other influence factors appear, and the growth rate of growing diamonds is partly dependent on the crystalline form of superfluous unabsorbed carbon source, flaky regrown graphite or small diamond crystals nucleated spontaneously. The present form is determined by the growth temperature if the pressure isfixed. Different from spontaneous diamond nuclei, the appearance of regrown graphite in the diamondstable region can retard the growth rate of gem diamonds substantially, even if the temperature gradient keeps unchanged. On the other hand, the formation mechanism of metastable regrown graphite in the diamond-stable region is also explained.

  4. 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.

  5. The character of FeMn-1# powder catalyst and its influence on the synthesis of diamond

    Science.gov (United States)

    Liu, W. Q.; Ma, H. A.; Han, Q. G.; Hu, M. H.; Li, R.; Zeng, M. F.; Jia, X.

    2009-06-01

    In this paper industrial diamond crystal was synthesized using FeMn-1# powder catalyst in China-type cubic high-pressure apparatus at 5.7 GPa and 1400-1600 °C. The growth feature of diamond in the graphite-FeMn-1# system was researched. Optical microscope observation showed that all the diamond crystals were light yellow octahedral with grain size of 0.3-0.5 mm. There are also plenty of bubbles in the crystals. By SEM, we can see that the surface of diamond is smooth and the crystal is intact. Mössbauer spectrum was used to detect the impurity in the diamonds.

  6. 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.

  7. 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.

  8. 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.

  9. Simultaneous Determination of Oxygen and Nitrogen in Synthetic Diamonds by Inert Gas High Temperature Extraction-Impulse Heating Method%惰气高温萃取-脉冲加热法同时测定人造金刚石中氧和氮

    Institute of Scientific and Technical Information of China (English)

    高光洁子; 李艳萍; 冯圣雅; 谢琰军; 况春江; 曹枨

    2014-01-01

    A method for the simultaneous determination of oxygen and nitrogen in synthetic diamonds by inert gas high temperature extraction-impulse heating method was proposed. The sample weight, the selection of analysis power and the calibration curves of oxygen and nitrogen were discussed. Oxygen and nitrogen in analytical samples are determined. Values of RSDs (n=7) for oxygen and nitrogen were less than 4. 5% and 4. 0% respectively. The analytical results of oxygen and nitrogen obtained by the proposed method were in good agreement with those by inert gas fusion-impulse heating method.

  10. A comparison of the abilities of natural rubber (NR) and synthetic polyisoprene cis-1,4 rubber (IR) to crystallize under strain at high strain rates.

    Science.gov (United States)

    Candau, Nicolas; Chazeau, Laurent; Chenal, Jean-Marc; Gauthier, Catherine; Munch, Etienne

    2016-02-07

    Strain induced crystallization (SIC) of a natural rubber (NR) and a synthetic rubber (IR) with a high amount of cis-1,4 units (98.6%) is studied, thanks to in situ wide angle X-ray (WAXS) experiments at room temperature performed in a large range of strain rates. During stretching at a low strain rate (4.2 × 10(-3) s(-1)), SIC in IR occurs at a larger stretching ratio than in NR. As a result, the crystallinity index at a given stretching ratio is lower in IR than in NR, in spite of the similar crosslink densities of the chains involved in the crystallization in both materials. This lower ability for crystallization in IR is attributed to the presence of branching along its backbone and its lower stereoregularity. Conversely, dynamic experiments performed at high strain rates (10(1)/10(2) s(-1)) show for both materials a similar ability to crystallize. This unexpected result is confirmed by monotonic tensile tests performed in a large range of strain rates. The reason is thermodynamic: the chain extension plays a predominant role compared to the role of the microstructure defects when the strain rate is high, i.e. when the kinetics of the crystallite nucleation forces the crystallization to occur at a large stretching ratio. A thermodynamic model enables qualitative reproduction of the experimental results.

  11. Ion implantation of diamond: Damage, doping, and lift-off

    Energy Technology Data Exchange (ETDEWEB)

    Parikh, N.R.; McGucken, E.; Swanson, M.L. [North Carolina Univ., Chapel Hill, NC (United States). Dept. of Physics and Astronomy; Hunn, J.D.; White, C.W.; Zuhr, R.A. [Oak Ridge National Lab., TN (United States)

    1993-09-01

    In order to make good quality economical diamond electronic devices, it is essential to grow films and to dope these films to obtain n- and p- type conductivity. This review talk discuss first doping by ion implantation plus annealing of the implantation damage, and second flow to make large area single crystal diamonds. C implantation damage below an estimated Frenkel defect concentration of 7% could be recovered almost completely by annealing at 950C. For a defect concentration between 7 and 10%, a stable damage form of diamond (``green diamond``) was formed by annealing. At still higher damage levels, the diamond graphitized. To introduce p-type doping, we have co-implanted B and C into natural diamond at 77K, followed by annealing up to 1100C. The resulting semiconducting material has electrical properties similar to those of natural B-doped diamond. To create n-type diamond, we have implanted Na{sup +}, P+ and As{sup +} ions and have observed semiconducting behavior. This has been compared with carbon or noble element implantation, in an attempt to isolate the effect of radiation damage. Recently, in order to obtain large area signal crystals, we have developed a novel technique for removing thin layers of diamond from bulk or homoepitaxial films. This method consists of ion implantation, followed by selective etching. High energy (4--5 MeV) implantation of carbon or oxygen ions creates a well-defined layer of damaged diamond buried at a controlled depth. This layer is graphitized and selectivity etched either by heating at 550C in an oxygen ambient or by electrolysis. This process successfully lifts off the diamond plate above the graphite layer. The lift-off method, combined with well-established homoepitaxial growth processes, has potential for fabrication of large area single-crystal diamond sheets.

  12. High-temperature long-lasting stability assessment of a single-crystal diamond detector under high-flux neutron irradiation

    Science.gov (United States)

    Pilotti, R.; Angelone, M.; Marinelli, M.; Milani, E.; Verona-Rinati, G.; Verona, C.; Prestopino, G.; Montereali, R. M.; Vincenti, M. A.; Schooneveld, E. M.; Scherillo, A.; Pietropaolo, A.

    2016-11-01

    An innovative diamond detector layout is presented that is designed to operate at high temperature under intense neutron and gamma fluxes. It is made of a 500 μm “electronic grade” diamond film with 100 nm thick Ag metal contacts deposited onto each surface of the film by means of thermal evaporation. A 2 μ \\text{m} thick layer of 6LiF has been deposited on top of one of the two Ag contacts to make the detector sensitive to thermal neutrons. The device was tested at the ISIS spallation neutron source (Rutherford Appleton Laboratory, UK) using the INES beam line. The detector was continuously irradiated for 100 hours in vacuum (p = 10-5 \\text{mbar}) , exposed to a neutron flux of about 106 n cm-2 s-1 at a temperature T =150 ^\\circ \\text{C} . The aim of this experiment was to study the time dependence of the diamond detector performance while operating at high temperature under irradiation, providing a first experimental proof of reliable continuous operation for 100 hours at high temperature in a harsh environment.

  13. 动压法合成金刚石的发展史①--动压合成金刚石之一%Development History of Diamond Synthesis by Dynamic Pressure Technique---synthetic diamond by dynamic pressure technique NO.1

    Institute of Scientific and Technical Information of China (English)

    张书达

    2014-01-01

    This article expounds the development histroy of the diamond synthesis.By the inspiration of the earliest discovery of diamond from meteorite,people started to research on diamond synthesis by dynamic pressure technique.The development and perspective of the dynamic pressure technique in diamond industry in China has also been discussed in this article.%文章论述了最早人们从陨石中发现金刚石,并从中受到启发,开始研究通过动态高压的方法合成金刚石的发展历程,并论述了我国金刚石行业动态高压法合成的发展和前景。

  14. Noble gases in diamonds - Occurrences of solarlike helium and neon

    Science.gov (United States)

    Honda, M.; Reynolds, J. H.; Roedder, E.; Epstein, S.

    1987-01-01

    Seventeen diamond samples from diverse locations were analyzed for the contents of He, Ar, Kr, and Xe, and of their isotopes, using a Reynolds (1956) type glass mass spectrometer. The results disclosed a large spread in the He-3/He-4 ratios, ranging from values below atmospheric to close to the solar ratio. In particular, solarlike He-3/He-4 ratios were seen for an Australian colorless diamond composite and an Arkansas diamond, which also displayed solarlike neon isotopic ratios. Wide variation was also observed in the He-4/Ar-40 ratios, suggesting a complex history for the source regions and the diamond crystallization processes.

  15. Fabrication of three dimensional diamond ultraviolet photodetector through down-top method

    Science.gov (United States)

    Liu, Zhangcheng; Ao, Jin-Ping; Li, Fengnan; Wang, Wei; Wang, Jingjing; Zhang, Jingwen; Wang, Hong-Xing

    2016-10-01

    Three dimensional diamond ultraviolet (UV) photodetector have been fabricated on diamond epitaxial layer through down-top approach, where diamond epitaxial layer was grown between metal electrodes. A thin diamond epitaxial layer was first grown on high-pressure high-temperature single crystal diamond substrate. Then, the diamond epitaxial layer was covered by interdigitated tungsten electrodes. Furthermore, another diamond epitaxial layer was grown on uncovered area. At last, UV-Ozone treatment was used to oxidize the surface. The optoelectronic performance of the photodetector was characterized, exhibiting a large responsivity and a repeatable transient response behavior. Moreover, down-top process is beneficial for the electrode conductivity stability. Also, an ohmic contact could be formed between tungsten and diamond during growth. The results indicate that down-top process is an efficient way for fabrication of three dimensional diamond photodetectors.

  16. 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

  17. Thermally induced crystallization kinetics of uncrosslinked and unfilled synthetic cis-1,4-polyisoprene rubber monitored by shear rheological tests

    Science.gov (United States)

    Yang, Wei; Hong, Daesun; Kim, Hyungsu; Kim, Byungsoo; Chang, Wenji V.

    2016-11-01

    This study demonstrates the unique capability of a shear rotational rheometer for studying the thermally induced crystallization (TIC) of uncrosslinked and unfilled cis-1,4-polyisoprene rubber (IR). At temperatures below -15°C, a crystallization phenomenon (TIC) occurred in a quasi-unstrained IR specimen. Such a distinguished phenomenon was determined from the steady and sharp changes of both tanδ and the modulus. The changing ratio of those parameters with time characterizes the crystallization rate, on which the effects of the compressive force magnitude, testing repeat, and temperature are studied. The crystallization rate was shown to depend less on the magnitude of normal force, but depended largely on the specimen's previous testing history. A specimen not fully recovered from the previous crystallized memory showed a faster rate than before. More cooling to -25°C increased the crystallization rate, but the slow crystallization helped increase the final crystallinity. The crystallization rate was further interpreted by the Avrami equation to propose the crystal structure, whose morphological feature was shown in agreement with the reported TEM and X-ray results. However, our study found a thermo-mechanically aged specimen showed a very different rheological behavior at the late stage of crystallization suggesting the crystalline metamorphosis. But this unexpected behavior turned out to be unrecoverable indicating a property failure due to material aging more plausibly. All these findings were successfully monitored by the rheometer. It is expected the well-organized rheometric measurements can sufficiently supplement some instrumental limitations of the traditional crystallization monitoring analyzers on soft materials.

  18. Formation of Mixture of A and C Centres in Diamond Synthesized with Fe90Ni10-C-High-Content Additive NaN3 by HPHT

    Institute of Scientific and Technical Information of China (English)

    LIANG Zhong-Zhu; JIA xiao-Peng; LIANG Jing-Qiu

    2007-01-01

    Very rich nitrogen concentration with the dominant C centres and some A centres are found in diamonds grown from a Fe90Ni10-C-high-content NaN3 additive system.The concentrations of C centres rapidly increase with increasing content of NaN3 additive,while the concentrations of A centres increase slowly.The total nitrogen concentration tends to increa.rapidly with increasing content of NaN3 additive when the content of NaNa is below 0.7wt%.However,the total concentration of nitrogen in the diamonds increases slowly when the content of NaN3 is further increased up to 1.0wt%,and the total nitrogen average concentration are calculated to be around 2230ppm for most of the analysed synthetic diamonds.Furthermore,the nitrogen impurities in different crystal sectors of the diamonds are inhomogeneously distributed.The nitrogen impurities in the diamonds in [111] zones are incorporated more easily than that in[100].

  19. 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.

  20. 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.

  1. Extended depth-of-field 3D endoscopy with synthetic aperture integral imaging using an electrically tunable focal-length liquid-crystal lens.

    Science.gov (United States)

    Wang, Yu-Jen; Shen, Xin; Lin, Yi-Hsin; Javidi, Bahram

    2015-08-01

    Conventional synthetic-aperture integral imaging uses a lens array to sense the three-dimensional (3D) object or scene that can then be reconstructed digitally or optically. However, integral imaging generally suffers from a fixed and limited range of depth of field (DOF). In this Letter, we experimentally demonstrate a 3D integral-imaging endoscopy with tunable DOF by using a single large-aperture focal-length-tunable liquid crystal (LC) lens. The proposed system can provide high spatial resolution and an extended DOF in synthetic-aperture integral imaging 3D endoscope. In our experiments, the image plane in the integral imaging pickup process can be tuned from 18 to 38 mm continuously using a large-aperture LC lens, and the total DOF is extended from 12 to 51 mm. To the best of our knowledge, this is the first report on synthetic aperture integral imaging 3D endoscopy with a large-aperture LC lens that can provide high spatial resolution 3D imaging with an extend DOF.

  2. 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.

  3. Evolution of diamond resorption in a silicic aqueous fluid at 1-3 GPa: Application to kimberlite emplacement and mantle metasomatism

    Science.gov (United States)

    Zhang, Zhihai; Fedortchouk, Yana; Hanley, Jacob J.

    2015-06-01

    Natural diamonds grow and partially dissolve during mantle metasomatism and undergo further resorption during the ascent to the Earth's surface in kimberlite magmas. This study uses atomic force microscopy (AFM) for quantitative characterization of diamond resorption morphology in order to provide robust constraints of the composition of kimberlitic and mantle metasomatic fluids. We performed experiments in a piston-cylinder apparatus at pressures (P) of 1-3 GPa and temperatures (T) of 1150-1400 °C to examine the impact of P, T, and silica content of an aqueous fluid on diamond dissolution. Petrographic observation and microthermometry of synthetic fluid inclusions trapped in olivine at the run conditions provide constraints on the composition and density of the fluid reacting with the diamond. Our results confirm an inverse relationship between P and T on diamond dissolution kinetics. A P increase of 1 GPa suppresses diamond oxidation rates by the same value as a T decrease by 50 °C, while the transformation rate of diamond crystal morphology from octahedron to tetrahexahedron increases with both P and T. All dissolved diamonds develop glossy surfaces, ditrigonal {111} faces, sheaf striations, and negative trigons, while circular pits only occur in aqueous fluids with low silica content (≤ 4.2 mol/kg) at 1 GPa. We identify five distinct morphological groups of trigons: two types of point-bottomed (p/b) (trumpet- and V-shaped) and three types of flat-bottomed (f/b) (trumpet-shaped, trapezoid-shaped and rounded). AFM measurements of trigons from two successive runs showed three stages of their evolution. Etch pits nucleate at defects as trumpet p/b trigons with the vertical dissolution rate (Vd) faster than the dissolution rates at the surface free of defects; they further develop by growth of the bottoms in (111) plane to create trumpet-shaped f/b trigons accompanied by decrease in Vd; and finally form trapezoid-shaped f/b trigon with constant wall angles. The

  4. Synthesis of silicon carbide coating on diamond by microwave heating of diamond and silicon powder: A heteroepitaxial growth

    Energy Technology Data Exchange (ETDEWEB)

    Leparoux, S. [Empa, Department of Materials Technology, Feuerwerkerstrasse 39, CH-3602 Thun (Switzerland)], E-mail: susanne.leparoux@empa.ch; Diot, C. [Consultant, allee de Mozart 10, F-92300 Chatillon (France); Dubach, A. [Empa, Department of Materials Technology, Feuerwerkerstrasse 39, CH-3602 Thun (Switzerland); Vaucher, S. [Empa, Department of Materials Technology, Feuerwerkerstrasse 39, CH-3602 Thun (Switzerland)

    2007-10-15

    When a powder mixture of diamond and silicon is heated by microwaves, heteroepitaxial growth of SiC is observed on the (1 1 1) as well as on the (1 0 0) faces of the diamond. The SiC over-layer was characterized by X-ray diffraction and scanning electron microscopy. High-resolution scanning electron microscopy shows the presence of triangular silicon carbide on the (1 1 1) faces of diamond while prismatic crystals are found on the (1 0 0) faces. The crystal growth seems to be favored in the plane parallel to the face (1 1 1)

  5. Synthetic Hemozoin (β-Hematin) Crystals Nucleate at the Surface of Neutral Lipid Droplets that Control Their Sizes.

    Science.gov (United States)

    Ambele, Melvin A; Sewell, B Trevor; Cummings, Franscious R; Smith, Peter J; Egan, Timothy J

    2013-10-02

    Emulsions of monopalmitoylglycerol (MPG) and of a neutral lipid blend (NLB), consisting of MPG, monostearoylglycerol, dipalmitoylglycerol, dioleoylglycerol and dilineoylglycerol (4:2:1:1:1), the composition associated with hemozoin from the malaria parasite Plasmodium falciparum, have been used to mediate the formation of β-hematin microcrystals. Transmission electron microscopy (TEM), electron diffraction and electron spectroscopic imaging/electron energy loss spectroscopy (ESI/EELS) have been used to characterize both the lipid emulsion and β-hematin crystals. The latter have been compared with β-hematin formed at a pentanol/aqueous interface and with hemozoin both within P. falciparum parasites and extracted from the parasites. When lipid and ferriprotoporphyrin IX solutions in 1:9 v/v acetone/methanol were thoroughly pre-mixed either using an extruder or ultrasound, β-hematin crystals were found formed in intimate association with the lipid droplets. These crystals resembled hemozoin crystals, with prominent {100} faces. Lattice fringes in TEM indicated that these faces made contact with the lipid surface. The average length of these crystals was 0.62 times the average diameter of NLB droplets and their size distributions were statistically equivalent after 10 min incubation, suggesting that the lipid droplets also controlled the sizes of the crystals. This most closely resembles hemozoin formation in the helminth worm Schistosoma mansoni, while in P. falciparum, crystal formation appears to be associated with the much more gently curved digestive vacuole membrane which apparently leads to formation of much larger hemozoin crystals, similar to those formed at the flat pentanol-water interface.

  6. Distribution and characteristics of diamonds from Myanmar

    Science.gov (United States)

    Win, T. T.; Davies, R. M.; Griffin, W. L.; Wathanakul, P.; French, D. H.

    2001-08-01

    Diamonds occur in headless placers at several locations within Myanmar. Twenty-six stones from the Momeik area of northern Myanmar and 111 stones from the Theindaw area of southern Myanmar have been studied to characterise their morphology, crystal forms, colour, degree of resorption, surface features, internal structures, mineral inclusions, and nitrogen content and aggregation state. Most stones grew originally as octahedra, but now show very high degrees of resorption, and highly polished surfaces, reflecting transport in a magma. Etch features are abundant, and breakage and abrasion are common, due to alluvial transport. Brown radiation spots are common, suggesting that these diamonds have a long history in surface environments. Cathodoluminescence (CL) images of plates and whole stones commonly display marked oscillatory zoning of yellow and blue bands, outlining octahedral growth zones. Many other stones show uniform yellow CL. Syngenetic mineral inclusions identified thus far are mainly of peridotitic paragenesis and include olivine, chromite and native iron. Infrared spectroscopy studies show that ˜10% of the diamonds have very low-N contents (Type II diamonds). More N-rich diamonds show high degrees of aggregation (Type IaAB). Both types are consistent with derivation from the upper mantle, rather than from crustal metamorphic sources. The primary source of these diamonds is believed to be an alkaline igneous rock (lamproitic rather than kimberlitic) but they may have reached their present locations via a secondary collector such as a sedimentary rock.

  7. X-ray Structure of Snow Flea Antifreeze Protein Determined by Racemic Crystallization of Synthetic Protein Enantiomers

    Energy Technology Data Exchange (ETDEWEB)

    Pentelute, Brad L.; Gates, Zachary P.; Tereshko, Valentina; Dashnau, Jennifer L.; Vanderkooi, Jane M.; Kossiakoff, Anthony A.; Kent, Stephen B.H. (UPENN); (UC)

    2008-08-20

    Chemical protein synthesis and racemic protein crystallization were used to determine the X-ray structure of the snow flea antifreeze protein (sfAFP). Crystal formation from a racemic solution containing equal amounts of the chemically synthesized proteins d-sfAFP and l-sfAFP occurred much more readily than for l-sfAFP alone. More facile crystal formation also occurred from a quasi-racemic mixture of d-sfAFP and l-Se-sfAFP, a chemical protein analogue that contains an additional -SeCH2- moiety at one residue and thus differs slightly from the true enantiomer. Multiple wavelength anomalous dispersion (MAD) phasing from quasi-racemate crystals was then used to determine the X-ray structure of the sfAFP protein molecule. The resulting model was used to solve by molecular replacement the X-ray structure of l-sfAFP to a resolution of 0.98 {angstrom}. The l-sfAFP molecule is made up of six antiparallel left-handed PPII helixes, stacked in two sets of three, to form a compact brick-like structure with one hydrophilic face and one hydrophobic face. This is a novel experimental protein structure and closely resembles a structural model proposed for sfAFP. These results illustrate the utility of total chemical synthesis combined with racemic crystallization and X-ray crystallography for determining the unknown structure of a protein.

  8. 单晶金刚石机械研磨与化学机械抛光工艺%Mechanical Lapping and Chemical-Mechanical Polishing Process for Single Crystal Diamond

    Institute of Scientific and Technical Information of China (English)

    薛洪明; 金洙吉; 史卓颖

    2015-01-01

    单晶金刚石在工业、国防等领域的应用日益广泛,对其加工表面质量的要求不断提高,使用常温低压的化学机械抛光可实现金刚石的超光滑低损伤表面加工。通过理论分析及实验研究得出,使用硅酸盐玻璃材质研磨盘进行研磨加工,可以将金刚石表面粗糙度Ra降至15~25 nm,且无明显机械划痕;在2 MPa压力及室温环境下进行单晶金刚石化学机械抛光实验,优选出Fenton试剂酸性水基抛光液,使用该抛光液抛光单晶金刚石可获得粗糙度Ra值4 nm以下的光滑表面。%Single crystal diamond is more and more widely used in national defense and industrial field , which requires better surface quality .The technique of chemical-mechanical polishing at normal-tempera-ture and low-pressure environment can achieve ultra-smooth diamond surface with low damage .Theoreti-cal analysis and experimental research show that the polished diamond surface roughness Ra can be re-duced to 15—25 nm without obvious mechanical scratches by using silicate glass as grinding disc .The chemical-mechanical polishing experiment was held under the condition of 2 MPa pressure and normal-temperature .Experimental results show that the water-based acidic Fenton reagent was effective in parti-cular process parameters , and overall surface roughness Ra was processed to be less than 4 nm.

  9. Acoustic and NMR investigations of melting and crystallization of indium-gallium alloys in pores of synthetic opal matrices

    Science.gov (United States)

    Pirozerskii, A. L.; Charnaya, E. V.; Lee, M. K.; Chang, L. J.; Nedbai, A. I.; Kumzerov, Yu. A.; Fokin, A. V.; Samoilovich, M. I.; Lebedeva, E. L.; Bugaev, A. S.

    2016-05-01

    The paper presents the results of studying the crystallization and melting processes of Ga-In eutectic alloys, which are embedded in opal matrices, using acoustic and NMR methods. The indium concentrations in the alloys were 4, 6, 9, and 15 at %. Measurements were performed upon cooling from room temperature to complete crystallization of the alloys and subsequent heating. It is revealed how the size effects and alloy composition influence the formation of phases with α- and β-Ga structures and on changes in the melting-temperature ranges. A difference was observed between the results obtained using acoustic and NMR methods, which was attributed to different temperature measurement conditions.

  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. Alpha particle response study of polycrstalline diamond radiation detector

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Amit; Topkar, Anita [Electronics Division, Bhabha Atomic Research Centre, Trombay, Mumbai-400085 (India)

    2016-05-23

    Chemical vapor deposition has opened the possibility to grow high purity synthetic diamond at relatively low cost. This has opened up uses of diamond based detectors for wide range of applications. These detectors are most suitable for harsh environments where standard semiconductor detectors cannot work. In this paper, we present the fabrication details and performance study of polycrystalline diamond based radiation detector. Effect of different operating parameters such as bias voltage and shaping time for charge collection on the performance of detector has been studied.

  12. 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.

  13. 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.

  14. 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.

  15. Facts and Artifacts in Interstellar Diamond Spectra

    Science.gov (United States)

    Mutschke, H.; Dorschner, J.; Henning, T.; Jager, C.; Ott, U.

    1995-12-01

    Absorption spectra of presolar diamonds extracted from the Murchison meteorite have been measured in the extended wavelength range 0.2--500 mu m in order to make available optical properties of this supposed component of interstellar carbon dust. In contrast to terrestrial natural and synthetic diamonds, spectra of the meteoritic diamonds show prominent bands in the middle-IR. In this Letter, experimental evidence is presented that the OH band at 3200 cm-1 and the CH bands in the 2800--3000 cm-1 range are not intrinsic features of the diamonds and that the band at 1100 cm-1 contains an artificial component due to the extraction procedure. In addition, in our spectra a conspicuous band at 120 cm-1 was found. If the intrinsic character of this band, which, up to now, is unidentified, is confirmed, it would offer a chance to observe interstellar diamonds, e.g., by the ISO satellite. We encourage laboratory astrophysicists and observers to study this promising possibility.

  16. 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.

  17. Mantle Degassing and Diamond Genesis:A Carbon Isotope Perspective

    Institute of Scientific and Technical Information of China (English)

    郑永飞

    1994-01-01

    The effect of Co2 and CH4 degassing from the mantle on the carbon isotopic composition of diamond has been quantitatively modeled in terms of the principles of Rayleigh distillation.Assuming the δ13 C value of -5‰ for the mantle,the outgassing of CO2 can result in the large negative δ13 C values of diamond,whereas the outgassing of CH4 can drive the δ13C values of diamond in the positive direction.The theoretical expectations can be used to explain the full range of δ13 C values from-34.4‰5 to+5‰ observed for natural diamonds.It is possible that diamond formation was triggered by the degassing of Co2 and/or CH4 from the mantle and the associated fractional crystallization of carbonate-bearing melt.

  18. An on-chip diamond optical parametric oscillator

    CERN Document Server

    Hausmann, B J M; Venkataraman, V; Deotare, P; Loncar, M

    2013-01-01

    Efficient, on-chip optical nonlinear processes are of great interest for the development of compact, robust, low-power consuming systems for applications in spectroscopy, metrology, sensing and classical and quantum optical information processing. Diamond holds promise for these applications, owing to its exceptional properties. However, although significant progress has been made in the development of an integrated diamond photonics platform, optical nonlinearities in diamond have not been explored much apart from Raman processes in bulk samples. Here, we demonstrate optical parametric oscillations (OPO) via four wave mixing (FWM) in single crystal diamond (SCD) optical networks on-chip consisting of waveguide-coupled microring resonators. Threshold powers as low as 20mW are enabled by ultra-high quality factor (1*10^6) diamond ring resonators operating at telecom wavelengths, and up to 20 new wavelengths are generated from a single-frequency pump laser. We also report the inferred nonlinear refractive index...

  19. Tracing the depositional history of Kalimantan diamonds by zircon provenance and diamond morphology studies

    Science.gov (United States)

    Kueter, Nico; Soesilo, Joko; Fedortchouk, Yana; Nestola, Fabrizio; Belluco, Lorenzo; Troch, Juliana; Wälle, Markus; Guillong, Marcel; Von Quadt, Albrecht; Driesner, Thomas

    2016-11-01

    Diamonds in alluvial deposits in Southeast Asia are not accompanied by indicator minerals suggesting primary kimberlite or lamproite sources. The Meratus Mountains in Southeast Borneo (Province Kalimantan Selatan, Indonesia) provide the largest known deposit of these so-called "headless" diamond deposits. Proposals for the origin of Kalimantan diamonds include the adjacent Meratus ophiolite complex, ultra-high pressure (UHP) metamorphic terranes, obducted subcontinental lithospheric mantle and undiscovered kimberlite-type sources. Here we report results from detailed sediment provenance analysis of diamond-bearing Quaternary river channel material and from representative outcrops of the oldest known formations within the Alino Group, including the diamond-bearing Campanian-Maastrichtian Manunggul Formation. Optical examination of surfaces of diamonds collected from artisanal miners in the Meratus area (247 stones) and in West Borneo (Sanggau Area, Province Kalimantan Barat; 85 stones) points toward a classical kimberlite-type source for the majority of these diamonds. Some of the diamonds host mineral inclusions suitable for deep single-crystal X-ray diffraction investigation. We determined the depth of formation of two olivines, one coesite and one peridotitic garnet inclusion. Pressure of formation estimates for the peridotitic garnet at independently derived temperatures of 930-1250 °C are between 4.8 and 6.0 GPa. Sediment provenance analysis includes petrography coupled to analyses of detrital garnet and glaucophane. The compositions of these key minerals do not indicate kimberlite-derived material. By analyzing almost 1400 zircons for trace element concentrations with laser ablation ICP-MS (LA-ICP-MS) we tested the mineral's potential as an alternative kimberlite indicator. The screening ultimately resulted in a small subset of ten zircons with a kimberlitic affinity. Subsequent U-Pb dating resulting in Cretaceous ages plus a detailed chemical reflection make

  20. Re-investigation of the crystal structure of enstatite under high-pressure conditions

    DEFF Research Database (Denmark)

    Periotto, Benedetta; Balic Zunic, Tonci; Nestola, Fabrizio

    2012-01-01

    A synthetic single crystal of pure orthoenstatite (MgSiO3, space group Pbca) has been investigated at high pressure for structural determinations by in situ single-crystal X‑ray diffraction using a diamond-anvil cell. Ten complete intensity data collections were performed up to 9.36 GPa. This study...... is mostly governed by significant volume decrease of the Mg1 and Mg2 octahedra, affecting in turn the kink of the tetrahedral chains, especially the TB chain of larger SiO4 tetrahedra. The Mg2 polyhedron undergoes the largest volume variation, 8.7%, due especially to the strong contraction of the longest...

  1. Coherent bremsstrahlung and channeling radiation from 40 and 150 GeV electrons and positrons traversing Si and diamond single crystals near planar directions

    Energy Technology Data Exchange (ETDEWEB)

    Medenwaldt, R.; Moeller, S.P.; Soerensen, A.H.; Uggerhoej, E. (Aarhus Univ. (Denmark). Inst. for Synchrotron Radiation); Elsener, K. (European Organization for Nuclear Research, Geneva (Switzerland)); Hage-Ali, M.; Siffert, P.; Stoquert, J. (Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires); Sona, P. (Florence Univ. (Italy). Dipt. di Fisica Istituto Nazionale di Fisica Nucleare, Florence (Italy))

    1991-05-09

    Along planar directions in both Si and C single crystals the radiation yields from 150GeV electrons are enhanced 40 times or more and the data present the first use of C crystals in the multi-hundred GeV region. For channeled electrons in Si the experimental results agree with calculations using the constant field approximation (CFA). Increasing incident angles reduce rapidly soft photon yields as expected from first order corrections to CFA. The first Born approximation only describes experimental results for large incident angles to planes. (orig.).

  2. Coherent bremsstrahlung and channeling radiation from 40 and 150 GeV electrons and positrons traversing Si and diamond single crystals near planar directions

    Science.gov (United States)

    Medenwaldt, R.; Møller, S. P.; Sørensen, A. H.; Uggerhøj, E.; Elsener, K.; Hage-Ali, M.; Siffert, P.; Stoquert, J.; Sona, P.

    1991-05-01

    Along planar directions in both Si and C single crystals the radiation yields from 150 GeV electrons are enhanced 40 times or more and the data present the first use of C crystals in the multi-hundred GeV region. For channeled electrons in Si the experimental results agree with calculations using the constant field approximation (CFA). Increasing incident angles reduce rapidly soft photon yields as expected from first order corrections to CFA. The first born approximation only describes experimental results for large incident angles to planes.

  3. Simultaneous measurement of pressure evolution of crystal structure and superconductivity in FeSe[subscript 0.92] using designer diamonds

    Energy Technology Data Exchange (ETDEWEB)

    Uhoya, Walter; Tsoi, Georgiy; Vohra, Yogesh; Wolanyk, Nathaniel; Rao, Sistla Muralidhara; Wu, Maw-Kuen; Weir, Samuel (LLNL); (UAB); (IP-Taiwan); (IWU)

    2017-04-19

    Simultaneous high-pressure X-ray diffraction and electrical resistance measurements have been carried out on a PbO-type {alpha}-FeSe{sub 0.92} compound to a pressure of 44 GPa and temperatures down to 4 K using designer diamond anvils at synchrotron source. A ambient temperature, a structural phase transition from a tetragonal (P4/nmm) phase to an orthorhombic (Pbnm) phase is observed at 11 GPa and the Pbnm phase persists up to 74 GPa. The superconducting transition temperature (T{sub c}) increases rapidly with pressure reaching a maximum of {approx}28 K at {approx}6 GPa and decreases at higher pressures, disappearing completely at 14.6 GPa. Simultaneous pressure-dependent X-ray diffraction and resistance measurements at low temperatures show superconductivity only in a low-pressure orthorhombic (Cmma) phase of the {alpha}-FeSe{sub 0.92}. Upon increasing pressure at 10 K near T{sub c}, crystalline phases change from a mixture of orthorhombic (Cmma) and hexagonal (P63/mmc) phases to a high-pressure orthorhombic (Pbnm) phase near 6.4 GPa where T{sub c} is maximum.

  4. Evidence of light guiding in ion-implanted diamond

    CERN Document Server

    Lagomarsino, S; Bosia, F; Vannoni, M; Calusi, S; Giuntini, L; Massi, M

    2016-01-01

    We demonstrate the feasibility of fabricating light-waveguiding microstructures in bulk single-crystal diamond by means of direct ion implantation with a scanning microbeam, resulting in the modulation of the refractive index of the ion-beam damaged crystal. Direct evidence of waveguiding through such buried microchannels is obtained with a phase-shift micro-interferometric method allowing the study of the multi-modal structure of the propagating electromagnetic field. The possibility of defining optical and photonic structures by direct ion writing opens a range of new possibilities in the design of quantum-optical devices in bulk single crystal diamond.

  5. Magnetically Orchestrated Formation of Diamond at Lower Temperatures and Pressures

    Science.gov (United States)

    Little, Reginald B.; Lochner, Eric; Goddard, Robert

    2005-01-01

    magnetic organization of carbon, metal and hydrogen radicals for lower temperature and pressure synthesis. Here we show that strong static external magnetic field (>15 T) enhances the formation of single crystal diamond at lower pressure and even atmospheric pressure with implications for much better, faster high quality diamond formation by magnetization of current high pressure and temperature technology.

  6. Bases of the Mantle-Carbonatite Conception of Diamond Genesis

    Science.gov (United States)

    Litvin, Yuriy; Spivak, Anna; Kuzyura, Anastasia

    2016-04-01

    In the mantle-carbonatite conception of diamond genesis, the results of physic-chemical experiments are coordinated with the data of analytic mineralogy of primary inclusions in natural diamonds. Generalization of the solutions of principal genetic problems constitutes the bases of the conception. The solutions are following: (1) it is grounded that diamond-parental melts of the upper mantle have peridotite/eclogite - carbonatite - carbon compositions, of the transition zone - (wadsleite↔ringwoodite) - majorite - stishovite - carbonatite - carbon compositions, and of the lower mantle - periclase/wustite - bridgmanite - Ca-perovskite -stishovite - carbonatite - carbon compositions; (2) a construction of generalized diagrams for the diamond-parental media, which reveal changeable compositions of the growth melts of diamonds and associated phases, their genetic relations to the mantle substance, and classification connections of the primary inclusions in natural diamonds; (3) experimental equilibrium phase diagrams of syngenesis of diamonds and primary inclusions, which characterize the nucleation and growth conditions of diamonds and a capture of paragenetic and xenogenetic minerals by the growing diamonds; (4) a determination of the phase diagrams of diamonds and inclusions syngenesis under the regime of fractional crystallization, which discover the regularities of ultrabasic-basic evolution and paragenesis transitions in the diamond-forming systems of the upper and lower mantle. The evidence of the physic-chemically united mode of diamond genesis at the mantle depths with different mineralogy is obtained. References. Litvin Yu.A. (2007). High-pressure mineralogy of diamond genesis. In: Advances in High-Pressure Mineralogy (edited by Eiji Ohtani), Geological Society of America Special paper 421, 83-103. Litvin Yu.A. (2012). Experimental study of physic-chemical conditions of natural diamond formation on an example of the eclogite-carbonatite-sulphide-diamond

  7. Spectroscopic constraints on growth of Siberian mixed-habit diamonds

    Science.gov (United States)

    Skuzovatov, Sergei Yu.; Zedgenizov, Dmitry A.; Rakevich, Alexander L.

    2017-06-01

    Notable within-crystal variability of mineralogical and geochemical properties of single natural diamonds are commonly attributed to changing chemistry of parental fluids, sources of carbon and redox conditions of diamond precipitation. A distinct type of compositional heterogeneity (mixed-habit structure) is well-known to occur in diamonds as well as in many other minerals due to purely "structural" reasons that are unequal crystal chemistry of crystallographically different faces and selective absorption and fractionation of impurities between adjacent growth pyramids. Based on the combined cathodoluminescence, Fourier-transformed infrared spectroscopy and photoluminescence spectroscopy, study of nine diamond crystals with different growth histories and external morphology, but all showing mixed-habit patterns at different growth stages, we show that mixed-diamonds may grow in closed system conditions or with a slowly decreasing growth rate from a media with a much lower impurity content than previously thought. Intracrystal nitrogen distribution seems to be a function of growth rate even in the cases of unusual impurity partitioning between growth sectors. Generally poor with IR-active hydrogen at moderate nitrogen aggregation parameters, studied diamonds likely resemble the low hydrogen content from the growth medium that, for cubic diamonds, was typically suggested hydrogen-rich and a crucial factor for growth of cubic and mixed-habit diamonds. We also show that mixed-habit diamond growth may occur not only in peridotitic suite but also in an extended field of geochemical affinities from high-Ni to low-Ni or maybe even Ni-free environments, such as pyroxenitic or eclogitic.

  8. 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.

  9. 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

  10. 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

  11. 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.

  12. 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...

  13. Diamond Processing by Focused Ion Beam - Surface Damage and Recovery

    CERN Document Server

    Bayn, Igal; Cytermann, Catherine; Meyler, Boris; Richter, Vladimir; Salzman, Joseph; Kalish, Rafi

    2011-01-01

    The Nitrogen Vacancy color center (NV-) in diamond is of great interest for novel photonic applications. Diamond nano-photonic structures are often implemented using Focused-Ion-Beam (FIB) processing, leaving a damaged surface which has a detrimental effect on the color center luminescence. The FIB processing effect on single crystal diamond surfaces and their photonic properties is studied by Time of Flight Secondary Ion Mass Spectrometry (TOF-SIMS) and photoluminescence (PL). Exposing the processed surface to hydrogen plasma, followed by chemical etching, drastically decreases implanted Ga concentration, resulting in a recovery of the NV- photo-emission and in a significant increase of the NV-/NV0 ratio.

  14. Single-color centers implanted in diamond nanostructures

    Science.gov (United States)

    Hausmann, Birgit J. M.; Babinec, Thomas M.; Choy, Jennifer T.; Hodges, Jonathan S.; Hong, Sungkun; Bulu, Irfan; Yacoby, Amir; Lukin, Mikhail D.; Lončar, Marko

    2011-04-01

    The development of material-processing techniques that can be used to generate optical diamond nanostructures containing a single-color center is an important problem in quantum science and technology. In this work, we present the combination of ion implantation and top-down diamond nanofabrication in two scenarios: diamond nanopillars and diamond nanowires. The first device consists of a 'shallow' implant (~20 nm) to generate nitrogen-vacancy (NV) color centers near the top surface of the diamond crystal prior to device fabrication. Individual NV centers are then mechanically isolated by etching a regular array of nanopillars in the diamond surface. Photon anti-bunching measurements indicate that a high yield (>10%) of the devices contain a single NV center. The second device demonstrates 'deep' (~1 μm) implantation of individual NV centers into diamond nanowires as a post-processing step. The high single-photon flux of the nanowire geometry, combined with the low background fluorescence of the ultrapure diamond, allowed us to observe sustained photon anti-bunching even at high pump powers.

  15. Fabrication of Diamond Based Sensors for Use in Extreme Environments

    Directory of Open Access Journals (Sweden)

    Gopi K. Samudrala

    2015-04-01

    Full Text Available Electrical and magnetic sensors can be lithographically fabricated on top of diamond substrates and encapsulated in a protective layer of chemical vapor deposited single crystalline diamond. This process when carried out on single crystal diamond anvils employed in high pressure research is termed as designer diamond anvil fabrication. These designer diamond anvils allow researchers to study electrical and magnetic properties of materials under extreme conditions without any possibility of damaging the sensing elements. We describe a novel method for the fabrication of designer diamond anvils with the use of maskless lithography and chemical vapor deposition in this paper. This method can be utilized to produce diamond based sensors which can function in extreme environments of high pressures, high and low temperatures, corrosive and high radiation conditions. We demonstrate applicability of these diamonds under extreme environments by performing electrical resistance measurements during superconducting transition in rare earth doped iron-based compounds under high pressures to 12 GPa and low temperatures to 10 K.

  16. Diamond-cBN alloy: A universal cutting material

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Pei [Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China); High Pressure Science and Engineering Center and Department of Physics and Astronomy, University of Nevada Las Vegas, Las Vegas, Nevada 89154 (United States); He, Duanwei, E-mail: duanweihe@scu.edu.cn; Kou, Zili; Li, Yong; Hu, Qiwei; Xu, Chao; Lei, Li; Wang, Qiming [Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China); Wang, Liping; Zhao, Yusheng [High Pressure Science and Engineering Center and Department of Physics and Astronomy, University of Nevada Las Vegas, Las Vegas, Nevada 89154 (United States); Xiong, Lun; Liu, Jing [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

    2015-09-07

    Diamond and cubic boron nitride (cBN) as conventional superhard materials have found widespread industrial applications, but both have inherent limitations. Diamond is not suitable for high-speed cutting of ferrous materials due to its poor chemical inertness, while cBN is only about half as hard as diamond. Because of their affinity in structural lattices and covalent bonding character, diamond and cBN could form alloys that can potentially fill the performance gap. However, the idea has never been demonstrated because samples obtained in the previous studies were too small to be tested for their practical performance. Here, we report the synthesis and characterization of transparent bulk diamond-cBN alloy compacts whose diameters (3 mm) are sufficiently large for them to be processed into cutting tools. The testing results show that the diamond-cBN alloy has superior chemical inertness over polycrystalline diamond and higher hardness than single crystal cBN. High-speed cutting tests on hardened steel and granite suggest that diamond-cBN alloy is indeed a universal cutting material.

  17. 各向异性金刚石结构的光子晶体%Anisotropic Photonic Crystals with Diamond Lattice

    Institute of Scientific and Technical Information of China (English)

    詹仪; 郑义; 李效增; 李秀霞

    2009-01-01

    基于平面波展开法,理论分析了填充率、介质各向异性的程度对单轴金刚石结构三维光子晶体禁带的影响.结果表明,当填充率和介质各向异性取合适的值,单轴各向异性金刚石结构光子晶体存在着完全带隙.介质各向异性的引入使该晶体的带隙变窄甚至完全关闭.在各个布里渊区域里,带隙率和带隙宽度随介质各向异性程度的变化而变化.各向异性的引入为调整光子禁带提供了一种方法.%With the plane-wave expansion method, the photonic-band-gap structure for a diamond lattice consisting of a uniaxial anisotropic-dielectric sphere in air was studied through tuning three inequivalent 1/3 Brillouin zone. The results show that choosing the suitable range of filling fraction and anisotropy, a full band gap opens in the whole Brillouin zone for this anisotropic PBG structure. The gap to midgap ratio and bandgap width is tunable as a result of the changing extraordinary axis orientation of the uniaxial sphere. Anisotropy in sphere dielectric function is found to narrow or even close band gaps. The band gap width and close rate are affected by the extraordinary axis directions and anisotropy. The results in turn suggest a potential approach to obtain some degree of tunability of the photonic band structures.

  18. Polycrystalline diamond detectors with three-dimensional electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Lagomarsino, S., E-mail: lagomarsino@fi.infn.it [University of Florence, Department of Physics, Via Sansone 1, 50019 Sesto Fiorentino (Italy); INFN Firenze, Via B. Rossi 1, 50019 Sesto Fiorentino (Italy); Bellini, M. [INO-CNR Firenze, Largo E. Fermi 6, 50125 Firenze (Italy); Brianzi, M. [INFN Firenze, Via B. Rossi 1, 50019 Sesto Fiorentino (Italy); Carzino, R. [Smart Materials-Nanophysics, Istituto Italiano di Tecnologia, Genova, Via Morego 30, 16163 Genova (Italy); Cindro, V. [Joseph Stefan Institute, Jamova Cesta 39, 1000 Ljubljana (Slovenia); Corsi, C. [University of Florence, Department of Physics, Via Sansone 1, 50019 Sesto Fiorentino (Italy); LENS Firenze, Via N. Carrara 1, 50019 Sesto Fiorentino (Italy); Morozzi, A.; Passeri, D. [INFN Perugia, Perugia (Italy); Università degli Studi di Perugia, Dipartimento di Ingegneria, via G. Duranti 93, 06125 Perugia (Italy); Sciortino, S. [University of Florence, Department of Physics, Via Sansone 1, 50019 Sesto Fiorentino (Italy); INFN Firenze, Via B. Rossi 1, 50019 Sesto Fiorentino (Italy); Servoli, L. [INFN Perugia, Perugia (Italy)

    2015-10-01

    The three-dimensional concept in diamond detectors has been applied, so far, to high quality single-crystal material, in order to test this technology in the best available conditions. However, its application to polycrystalline chemical vapor deposited diamond could be desirable for two reasons: first, the short inter-electrode distance of three-dimensional detectors should improve the intrinsically lower collection efficiency of polycrystalline diamond, and second, at high levels of radiation damage the performances of the poly-crystal material are not expected to be much lower than those of the single crystal one. We report on the fabrication and test of three-dimensional polycrystalline diamond detectors with several inter-electrode distances, and we demonstrate that their collection efficiency is equal or higher than that obtained with conventional planar detectors fabricated with the same material. - Highlights: • Pulsed laser fabrication of polycristalline diamond detectors with 3D electrodes. • Measurement of the charge collection efficiency (CCE) under beta irradiation. • Comparation between the CCE of 3D and conventional planar diamond sensors. • A rationale for the behavior of three-dimensional and planar sensors is given.

  19. Nanophotonics for quantum optics using nitrogen-vacancy centers in diamond.

    Science.gov (United States)

    Santori, C; Barclay, P E; Fu, K-M C; Beausoleil, R G; Spillane, S; Fisch, M

    2010-07-09

    Optical microcavities and waveguides coupled to diamond are needed to enable efficient communication between quantum systems such as nitrogen-vacancy centers which are known already to have long electron spin coherence lifetimes. This paper describes recent progress in realizing microcavities with low loss and small mode volume in two hybrid systems: silica microdisks coupled to diamond nanoparticles, and gallium phosphide microdisks coupled to single-crystal diamond. A theoretical proposal for a gallium phosphide nanowire photonic crystal cavity coupled to diamond is also discussed. Comparing the two material systems, silica microdisks are easier to fabricate and test. However, at low temperature, nitrogen-vacancy centers in bulk diamond are spectrally more stable, and we expect that in the long term the bulk diamond approach will be better suited for on-chip integration of a photonic network.

  20. Helium isotopic variability within single diamonds from the Orapa kimberlite pipe

    Science.gov (United States)

    Kurz, Mark D.; Jenkins, William J.; Lott, Dempsey E., III; Gurney, John J.

    1987-01-01

    The possible relationships between diamond mineralogy and helium isotopes were investigated by measuring the distribution and isotopic composition of He in a suite of well-characterized one-carat diamonds from the Orapa kimberlite, Botswana. The results of crushing in vacuo experiments indicated that most of He was contained in the matrix, rather than in the inclusions of the diamonds. Step-heating of individual diamonds at 2000 C released He of He-3/He-4 ratios that differed by up to a factor of 100 among the two heating steps, revealing large isotopic variations within individual diamonds. It is suggested that this internal isotopic variability is the result of stepwise graphitization: the first heating step initiates graphitization which nucleates around defects in a diamond, and the second step graphitizes the relatively defect-free regions of the diamond. This explanation predicts that the highest He-3/He-4 ratios should be found in most perfect crystals.

  1. Grow Large High-Quality Diamonds with Different Seed Surfaces

    Institute of Scientific and Technical Information of China (English)

    ZANG Chuan-Yi; JIA Xiao-Peng; MA Hong-An; LI Shang-Sheng; TIAN Yu; XIAO Hong-Yu

    2006-01-01

    Large high-quality type Ib diamond crystals have been grown with different seed surfaces by temperature gradient method at 5.5GPa, 1500-1600K, with NiMnCo alloy as the metal solvent. Compared with {100} as the growth surface, the growth region of large high-quality diamond crystals with {111} as the growth surface at a higher growth rate shifts markedly from lower temperatures (suitable for {100}-facet growth) to higher temperatures (suitable for {lll}-facet growth). However, regardless of different growth surfaces, {100} or {111}, the grown crystals of sheet-shaped shape are most difficult for metal inclusions to be trapped into, and whether or not matched growth between the seed surfaces and the growth temperatures determines the crystal shapes. In view of the growth rates, large high-quality diamond crystals of sheet-shaped shapes can be grown at a growth rate of above 2.5mg/h, while the growth rate of large high-quality diamond crystals should not be beyond 1.5mg/h for tower-shaped crystals.

  2. Crystal Dislocations

    Directory of Open Access Journals (Sweden)

    Ronald W. Armstrong

    2016-01-01

    Full Text Available Crystal dislocations were invisible until the mid-20th century although their presence had been inferred; the atomic and molecular scale dimensions had prevented earlier discovery. Now they are normally known to be just about everywhere, for example, in the softest molecularly-bonded crystals as well as within the hardest covalently-bonded diamonds. The advent of advanced techniques of atomic-scale probing has facilitated modern observations of dislocations in every crystal structure-type, particularly by X-ray diffraction topography and transmission electron microscopy. The present Special Issue provides a flavor of their ubiquitous presences, their characterizations and, especially, their influence on mechanical and electrical properties.

  3. Post-Synthetic Shaping of Porosity and Crystal Structure of Ln-Bipy-MOFs by Thermal Treatment

    Directory of Open Access Journals (Sweden)

    Philipp R. Matthes

    2015-07-01

    Full Text Available The reaction of anhydrous lanthanide chlorides together with 4,4′-bipyridine yields the MOFs 2∞[Ln2Cl6(bipy3]·2bipy, with Ln = Pr − Yb, bipy = 4,4′-bipyridine, and 3∞[La2Cl6(bipy5]·4bipy. Post-synthetic thermal treatment in combination with different vacuum conditions was successfully used to shape the porosity of the MOFs. In addition to the MOFs microporosity, a tuneable mesoporosity can be implemented depending on the treatment conditions as a surface morphological modification. Furthermore, thermal treatment without vacuum results in several identifiable crystalline high-temperature phases. Instead of collapse of the frameworks upon heating, further aggregation under release of bipy is observed. 3∞[LaCl3(bipy] and 2∞[Ln3Cl9(bipy3], with Ln = La, Pr, Sm, and 1∞[Ho2Cl6(bipy2] were identified and characterized, which can also exhibit luminescence. Besides being released upon heating, the linker 4,4′-bipyridine can undergo activation of C-C bonding in ortho-position leading to the in-situ formation of 4,4′:2′,2′′:4′′,4′′′-quaterpyridine (qtpy. qtpy can thereby function as linker itself, as shown for the formation of the network 2∞[Gd2Cl6(qtpy2(bipy2]·bipy. Altogether, the manuscript elaborates the influence of thermal treatment beyond the usual activation procedures reported for MOFs.

  4. MSR Studies in the Progress Towards Diamond Electronics

    Energy Technology Data Exchange (ETDEWEB)

    Connell, S. H., E-mail: connell@src.wits.ac.za [University of the Witwatersrand, Schonland Research Institute for Nuclear Sciences (South Africa); Machi, I. Z. [University of South Africa, Physics Department (South Africa); Bharuth-Ram, K. [University of KwaZulu Natal, School of Pure and Applied Physics (South Africa)

    2004-12-15

    The recent development of device quality synthetic diamond dramatically increases the potential of diamond as a wide band gap semiconductor. A remaining obstacle is the lack of shallow n-type dopants. Molecular dopant systems have been shown theoretically to lead to the shallowing of levels in the band gap. Some of these systems involve defect-hydrogen complexes. This, and other phenomena, motivate the study of the chemistry and dynamics of hydrogen in diamond. Much information on this topic has been obtained from Muon Spin Rotation (MSR) experiments. These experiments view the muonium (Mu {identical_to} {mu}{sup +}e{sup -}) atom as a light chemical analogue of hydrogen. Data on isolated muonium in diamond is reviewed, and evidence on formation of N-Mu-N (a shallow dopant candidate), the trapping of Mu at B-dopants, and fast quantum diffusion of muonium are discussed.

  5. Twinning of cubic diamond explains reported nanodiamond polymorphs

    Science.gov (United States)

    Németh, Péter; Garvie, Laurence A. J.; Buseck, Peter R.

    2015-12-01

    The unusual physical properties and formation conditions attributed to h-, i-, m-, and n-nanodiamond polymorphs has resulted in their receiving much attention in the materials and planetary science literature. Their identification is based on diffraction features that are absent in ordinary cubic (c-) diamond (space group: Fd-3m). We show, using ultra-high-resolution transmission electron microscope (HRTEM) images of natural and synthetic nanodiamonds, that the diffraction features attributed to the reported polymorphs are consistent with c-diamond containing abundant defects. Combinations of {113} reflection and rotation twins produce HRTEM images and d-spacings that match those attributed to h-, i-, and m-diamond. The diagnostic features of n-diamond in TEM images can arise from thickness effects of c-diamonds. Our data and interpretations strongly suggest that the reported nanodiamond polymorphs are in fact twinned c-diamond. We also report a new type of twin ( rotational), which can give rise to grains with dodecagonal symmetry. Our results show that twins are widespread in diamond nanocrystals. A high density of twins could strongly influence their applications.

  6. Nuclear techniques of analysis in diamond synthesis and annealing

    Energy Technology Data Exchange (ETDEWEB)

    Jamieson, D. N.; Prawer, S.; Gonon, P.; Walker, R.; Dooley, S.; Bettiol, A.; Pearce, J. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1996-12-31

    Nuclear techniques of analysis have played an important role in the study of synthetic and laser annealed diamond. These measurements have mainly used ion beam analysis with a focused MeV ion beam in a nuclear microprobe system. A variety of techniques have been employed. One of the most important is nuclear elastic scattering, sometimes called non-Rutherford scattering, which has been used to accurately characterise diamond films for thickness and composition. This is possible by the use of a database of measured scattering cross sections. Recently, this work has been extended and nuclear elastic scattering cross sections for both natural boron isotopes have been measured. For radiation damaged diamond, a focused laser annealing scheme has been developed which produces near complete regrowth of MeV phosphorus implanted diamonds. In the laser annealed regions, proton induced x-ray emission has been used to show that 50 % of the P atoms occupy lattice sites. This opens the way to produce n-type diamond for microelectronic device applications. All these analytical applications utilize a focused MeV microbeam which is ideally suited for diamond analysis. This presentation reviews these applications, as well as the technology of nuclear techniques of analysis for diamond with a focused beam. 9 refs., 6 figs.

  7. 高温高压下掺硼宝石级金刚石单晶生长特性的研究%Studies on synthesis of b oron-dop ed Gem-diamond single crystals under high temp erature and high presure

    Institute of Scientific and Technical Information of China (English)

    肖宏宇; 李尚升; 秦玉琨; 梁中翥; 张永胜; 张东梅; 张义顺

    2014-01-01

    In this paper, by choosing catalyst of FeNiMnCo alloy, boron-doped diamond single crystals are synthesized under 5.1-5.6 GPa and 1230-1600 ◦C; the temperature field is studied by finite element method (FEM). First, the P-T phase diagram for diamond single crystal growth, in the synthesis system of FeNiMnCo-C-B, is obtained, and the lowest synthesis conditions of 5.1 GPa and 1230 ◦C is found in the studies. By simulation with FEM, it is found that the content of boron element should be less and less in the growth of diamond single crystal in the {111} sector, and the reason is that the growth speed is reduced in the sectors. By growing diamond crystals with{111}faces, it is also found that the content of boron element in {111} secondary sector is greater than that in {111} primary sector, which is duo to the rapid growth of {111} secondary sector. Compared with the synthesis of diamond single crystal by film growth method, the diamond crystals thus obtained has no pits, the doping content of boron can be greater, and the diamond can be synthesized by temperature gradient method.%本文在5.1-5.6 GPa,1230-1600◦C的压力、温度条件下,以FeNiMnCo作为触媒,进行单质硼添加宝石级金刚石单晶的生长研究.借助于有限元法,对触媒内的温度场进行模拟.研究得到了FeNiMnCo-C-B体系下,金刚石单晶生长的P-T相图.该体系下合成金刚石单晶的最低压力、温度条件分别为5.1 GPa,1230◦C左右.研究发现,在单晶同一{111}扇区内部,硼元素呈内多外少的分布规律.有限元模拟结果给出,该分布规律是由在晶体生长过程中,{111}扇区的增长速度逐渐减小所致.{111}晶向的晶体生长实验结果表明,硼元素优先从{111}次扇区进入晶体.研究发现,这是该扇区增长速度相对较快,硼元素扩散逃离可用时间短导致的.另外,同磨料级掺硼金刚石单晶生长相比,对于温度梯度法生长掺硼宝石级金刚石单晶,由于晶体的增厚

  8. Tailoring of crystal phase and Néel temperature of cobalt monoxides nanocrystals with synthetic approach conditions

    Energy Technology Data Exchange (ETDEWEB)

    Ravindra, A. V.; Behera, B. C.; Padhan, P. [Department of Physics, Indian Institute of Technology Madras, Chennai 600036 (India); Lebedev, O. I.; Prellier, W. [Laboratoire CRISMAT, CNRS UMR 6508, ENSICAEN, 6 Bd du Marechal Juin, F-14050 Caen Cedex (France)

    2014-07-21

    Cobalt monoxide (CoO) nanocrystals were synthesized by thermal decomposition of cobalt oleate precursor in a high boiling point organic solvent 1-octadecene. The X-ray diffraction pattern and transmission electron microscopy studies suggest that pure face-centered-cubic (fcc) phase of CoO can be synthesized in the temperature range of 569–575 K. Thermolysis product at higher synthesis temperature 585 K is a mixture of fcc and hexagonal-closed-packed (hcp) phases. These nanocrystals are single crystals of CoO and exhibit mixture of two types of morphologies; one is nearly spherical with 5–25 nm diameter, and other one is 5–10 nm thick flake. The pure fcc-CoO nanocrystals show enhanced, and mixture of fcc- and hcp-CoO nanocrystals show reduced antiferromagnetic ordering temperature. Such results provide new opportunities for optimizing and enhancing the properties and performance of cobalt oxide nanomaterials.

  9. Study on growth of coarse grains of diamond with high quality under HPHT

    Institute of Scientific and Technical Information of China (English)

    ZHOU ShengGuo; ZANG ChuanYi; MA HongAn; LI XiaoLei; ZHANG HeMin; JIA XiaoPeng

    2009-01-01

    The growth of coarse grains of diamond was observed with graphite as carbon source and Fe80Ni20 alloy powder as catalyst at HPHT in a China-type SPD 6x1670T cubic high-pressure apparatus with highly exact control system. To synthesize coarse grains of diamond crystal with high quality, ad-vanced indirect heat assembly, powder catalyst technology and catalyst with optimal granularity were used. Especially the nucleation of diamond and the growth rate were strictly controlled by the opti-mized synthesis craft. At last, diamond crystals (about 0.85 mm) in the perfect hex-octahedron shape were successfully synthesized at ~5.4 Gpa and ~1360℃ in 60 min. The characteristic of crystal growth with powder catalyst technology under HPHT was discussed. The results and techniques might be useful for production of coarse grains of diamond.

  10. Localized vibrational modes in diamond

    Science.gov (United States)

    Murzaev, R. T.; Bachurin, D. V.; Korznikova, E. A.; Dmitriev, S. V.

    2017-03-01

    Discrete breather (DB) or, synonymously, intrinsic localized mode (ILM) is a spatially localized and time-periodic vibrational mode in a defect-free nonlinear lattice, e.g., in a crystal lattice. Standing DB and DB clusters (double and triple) are studied in diamond using molecular dynamics method with the AIREBO interatomic potentials. Single DB can be easily excited by applying initial shifts, A0, to a pair of nearest atoms along the valence bond in the opposite directions. Admissible excitation amplitudes are 0.09 ≤A0 /a0 ≤ 0.12, where a0 is the equilibrium interatomic distance. The core of a DB is a pair of nearest carbon atoms oscillating out-of-phase, while the neighboring atoms oscillate with one order of magnitude lower amplitudes. DB frequency is above the top of the phonon spectrum and increases with the oscillation amplitude. DB lives for more than 100 oscillation periods which approximately corresponds to 2 ps. The range of initial amplitudes and other conditions necessary for the excitation of double and triple DB clusters as well as their lifetime are investigated in detail. Two different mechanisms of energy exchange between DBs in the DB clusters are revealed, which is the main result of the present study. Our results contribute to a deeper understanding of the nonlinear lattice dynamics of diamond.

  11. 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.

  12. 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.

  13. 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.

  14. Regulatory roles of the N-terminal domain based on crystal structures of human pyruvate dehydrogenase kinase 2 containing physiological and synthetic ligands.

    Science.gov (United States)

    Knoechel, Thorsten R; Tucker, Alec D; Robinson, Colin M; Phillips, Chris; Taylor, Wendy; Bungay, Peter J; Kasten, Shane A; Roche, Thomas E; Brown, David G

    2006-01-17

    Pyruvate dehydrogenase kinase (PDHK) regulates the activity of the pyruvate dehydrogenase multienzyme complex. PDHK inhibition provides a route for therapeutic intervention in diabetes and cardiovascular disorders. We report crystal structures of human PDHK isozyme 2 complexed with physiological and synthetic ligands. Several of the PDHK2 structures disclosed have C-terminal cross arms that span a large trough region between the N-terminal regulatory (R) domains of the PDHK2 dimers. The structures containing bound ATP and ADP demonstrate variation in the conformation of the active site lid, residues 316-321, which enclose the nucleotide beta and gamma phosphates at the active site in the C-terminal catalytic domain. We have identified three novel ligand binding sites located in the R domain of PDHK2. Dichloroacetate (DCA) binds at the pyruvate binding site in the center of the R domain, which together with ADP, induces significant changes at the active site. Nov3r and AZ12 inhibitors bind at the lipoamide binding site that is located at one end of the R domain. Pfz3 (an allosteric inhibitor) binds in an extended site at the other end of the R domain. We conclude that the N-terminal domain of PDHK has a key regulatory function and propose that the different inhibitor classes act by discrete mechanisms. The structures we describe provide insights that can be used for structure-based design of PDHK inhibitors.

  15. 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.

  16. Dependence of Limited Growth Rate of High-Quality Gem Diamond on Growth Conditions

    Institute of Scientific and Technical Information of China (English)

    TIAN Yu; MA Hong-An; LI Shang-Sheng; XIAO Hong-Yu; ZHANG Ya-Fei; HUANG Guo-Feng; MA Li-Qiu; JIA Xiao-Peng

    2007-01-01

    The growth rate of diamond has been investigated for a long time and researchers have been attempting to enhance the growth rate of high-quality gem diamond infinitely. However, it has been found according to previous research results that the quality of diamond is debased with the increase of growth rate. Thus, under specific conditions, the growth rate of high-quality diamond cannot exceed a limited value that is called the limited growth rate of diamond. We synthesize a series of type Ib gem diamonds by temperature gradient method under high pressure and high temperature (HPHT) using the as-grown {100} face. The dependence of limited growth rate on growth conditions is studied. The results show that the limited growth rate increases when synthetic temperature decreases, also when growth time is prolonged.

  17. Resonant enhancement of the zero-phonon emission from a color center in a diamond cavity

    CERN Document Server

    Faraon, Andrei; Santori, Charles; Fu, Kai-Mei C; Beausoleil, Raymond G

    2010-01-01

    We demonstrate coupling of the zero-phonon line of individual nitrogen-vacancy centers and the modes of microring resonators fabricated in single-crystal diamond. A zero-phonon line enhancement exceeding ten-fold is estimated from lifetime measurements at cryogenic temperatures. The devices are fabricated using standard semiconductor techniques and off-the-shelf materials, thus enabling integrated diamond photonics.

  18. Diamond and silicon pixel detectors in high radiation environments

    Energy Technology Data Exchange (ETDEWEB)

    Tsung, Jieh-Wen

    2012-10-15

    Diamond pixel detector is a promising candidate for tracking of collider experiments because of the good radiation tolerance of diamond. The diamond pixel detector must withstand the radiation damage from 10{sup 16} particles per cm{sup 2}, which is the expected total fluence in High Luminosity Large Hadron Collider. The performance of diamond and silicon pixel detectors are evaluated in this research in terms of the signal-to-noise ratio (SNR). Single-crystal diamond pixel detectors with the most recent readout chip ATLAS FE-I4 are produced and characterized. Based on the results of the measurement, the SNR of diamond pixel detector is evaluated as a function of radiation fluence, and compared to that of planar-silicon ones. The deterioration of signal due to radiation damage is formulated using the mean free path of charge carriers in the sensor. The noise from the pixel readout circuit is simulated and calculated with leakage current and input capacitance to the amplifier as important parameters. The measured SNR shows good agreement with the calculated and simulated results, proving that the performance of diamond pixel detectors can exceed the silicon ones if the particle fluence is more than 10{sup 15} particles per cm{sup 2}.

  19. Diamond growth history from in situ measurement of Pb and S isotopic compositions of sulfide inclusions

    Science.gov (United States)

    Rudnick, Roberta L.; Eldridge, C. Stewart; Bulanova, Galina P.

    1993-01-01

    In a continuing effort to understand crust-mantle dynamics, we have determined the S and Pb isotopic compositions of mantle sulfides encapsulated within diamonds from under the Siberian craton and compared these results to those of previously investigated African counterparts. Because diamond inclusions are isolated from exchange with surrounding mantle, they may preserve the history of diamond growth and act as direct tracers of the origins of mantle materials. Study of these inclusions may thus offer the best chance of recognizing global-scale interaction between Earth's crust and mantle. Although δ34S values of the Siberian sulfides do not deviate significantly from the mantle value of 0‰ ± 3‰, Pb isotopic compositions are highly variable. Pb isotopic compositions of sulfides from peridotitic suite diamonds generally plot near the terrestrial Pb growth curve, with model ages ranging between 0 and 2 Ga, whereas sulfides from eclogitic suite diamonds have radiogenic compositions, plotting beyond the growth curve. These results, which are similar to those for sulfides in African diamonds, suggest that the sulfides from eclogitic suite diamonds were derived from a source with an unusually high U/Pb ratio and may indicate a common process (such as subduction of crystal materials into the mantle) operating beneath Africa and Siberia. The absence of extremely radiogenic Pb in sulfides from eclogite xenoliths suggests that the radiogenic material from which eclogitic suite diamonds grew was a transient feature of the mantle, associated with diamond growth. The ultimate origin of this high U/Pb signature, however, remains enigmatic. Large variations in Pb isotopic composition of sulfides from different zones in a single peridotitic suite diamond document (1) crystallization of the diamond's core near 2.0 Ga, (2) growth of its outer zone in an environment with a high U/Pb ratio similar to the growth environment of eclogitic suite diamonds, and (3) growth of the

  20. 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.

  1. Measurement & Minimization of Mount Induced Strain on Double Crystal Monochromator Crystals

    Science.gov (United States)

    Kelly, J.; Alcock, S. G.

    2013-03-01

    Opto-mechanical mounts can cause significant distortions to monochromator crystals and mirrors if not designed or implemented carefully. A slope measuring profiler, the Diamond-NOM [1], was used to measure the change in tangential slope as a function of crystal clamping configuration and load. A three point mount was found to exhibit the lowest surface distortion (Diamond Light Source.

  2. Effect of grain size of polycrystalline diamond on its heat spreading properties

    Science.gov (United States)

    Simon, Roland B.; Anaya, Julian; Faili, Firooz; Balmer, Richard; Williams, Gruffudd T.; Twitchen, Daniel J.; Kuball, Martin

    2016-06-01

    The exceptionally high thermal conductivity of polycrystalline diamond (>2000 W m-1 K-1) makes it a very attractive material for optimizing the thermal management of high-power devices. In this paper, the thermal conductivity of a diamond sample capturing grain size evolution from nucleation towards the growth surface is studied using an optimized 3ω technique. The thermal conductivity is found to decrease with decreasing grain size, which is in good agreement with theory. These results clearly reveal the minimum film thickness and polishing thickness from nucleation needed to achieve single-crystal diamond performance, and thus enable production of an optimal polycrystalline diamond for heat-spreading applications.

  3. Sound speed and thermal property measurements of inert materials: laser spectroscopy and the diamond-anvil cell

    Energy Technology Data Exchange (ETDEWEB)

    Zaug, J.M.

    1997-07-01

    An indispensable companion to dynamical physics experimentation, static high-pressure diamond-anvil cell research continues to evolve, with laser diagnostic, as an accurate and versatile experimental deep planetary properties have bootstrapped each other in a process that has produced even higher pressures; consistently improved calibrations of temperature and pressure under static and dynamic conditions; and unprecedented data and understanding of materials, their elasticity, equations of state (EOS), and transport properties under extreme conditions. A collection of recent pressure and/or temperature dependent acoustic and thermal measurements and deduced mechanical properties and EOS data are summarized for a wide range of materials including H2, H2O, H2S, D2S, CO2, CH4, N2O, CH3OH,, SiO2, synthetic lubricants, PMMA, single crystal silicates, and ceramic superconductors. Room P&T sound speed measurements are presented for the first time on single crystals of beta-HMX. New high-pressure and temperature diamond cell designed and pressure calibrant materials are reviewed.

  4. Kinetics of diamond-silicon reaction under high pressure-high temperature conditions

    Science.gov (United States)

    Pantea, Cristian

    In this dissertation work, the kinetics of the reaction between diamond and silicon at high pressure-high temperature conditions was investigated. This study was motivated by the extremely limited amount of information related to the kinetics of the reaction in diamond-silicon carbide composites formation. It was found that the reaction between diamond and melted silicon and the subsequent silicon carbide formation is a two-stage process. The initial stage is a result of direct reaction of melted silicon with carbon atoms from the diamond surface, the phase boundary reaction. Further growth of SiC is much more complicated and when the outer surfaces of diamond crystals are covered with the silicon carbide layer it involves diffusion of carbon and silicon atoms through the SiC layer. The reaction takes place differently for the two regions of stability of carbon. In the graphite-stable region, the reaction between diamond and melted silicon is associated with the diamond-to-graphite phase transition, while in the diamond-stable region there is no intermediary step for the reaction. The data obtained at HPHT were fitted by the Avrami-Erofeev equation. It was found that the reaction is isotropic, the beta-SiC grown on different faces of the diamond crystals showing the same reaction rate, and that the controlling mechanism for the reaction is the diffusion. In the graphite-stable region the activation energy, 402 kJ/mol is slightly higher than in the diamond-stable region, 260 kJ/mol, as the reaction between diamond and melted silicon is associated with the diamond-to-graphite phase transition, which has higher activation energy. In the diamond-stable region, the calculated activation energy is higher for micron size diamond powders (≈260 kJ/mol), while for nanocrystalline diamond powders a lower value of 170 kJ/mol was obtained. This effect was attributed to nanocrystalline structure and strained bonds within grain boundaries in SiC formed from nanosize diamond

  5. 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...

  6. 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.

  7. Crystal violet: Study of the photo-fading of an early synthetic dye in aqueous solution and on paper with HPLC-PDA, LC-MS and FORS

    Energy Technology Data Exchange (ETDEWEB)

    Confortin, Daria; Brustolon, Marina; Franco, Lorenzo [Dipartimento di Scienze Chimiche, Universita degli Studi di Padova, via Marzolo 1, 35131 Padova (Italy); Neevel, Han; Bommel, Maarten R van [Netherlands Institute for Cultural Heritage (ICN), PO Box 76709, 1070 KA, Amsterdam (Netherlands); Kettelarij, Albert J; Williams, Rene M, E-mail: daria.confortin@gmail.co [Molecular Photonics Group, Van' t Hoff Institute for Molecular Sciences, Faculty of Science, Universiteit van Amsterdam, Nieuwe Achtergracht 129, 1018 WS Amsterdam (Netherlands)

    2010-06-01

    The photo-fading of crystal violet (CV), one of the earliest synthetic dyes and an ink component, is examined both in solution and on paper. Aqueous solutions of CV were exposed to UV light (365nm) and samples were taken at constant time intervals and analysed with a High Performance Liquid Chromatography-Photo Diode Array (HPLC-PDA) and Liquid Chromatography-Mass Spectroscopy (LC-MS). Demethylation products were positively identified. Also, deamination probably occurred. The oxidation at the central carbon likely generates Michler's ketone (MK) or its derivatives, but still needs confirmation. To study CV on paper, Whatman paper was immersed in CV and exposed to UV light. Before and after different irradiation periods, reflectance spectra were recorded with Fibre Optic Reflectance Spectrophotometry (FORS). A decrease in CV concentration and a change in aggregation type for CV molecules upon irradiation was observed. Colorimetric L*a*b* values before and during irradiation were also measured. Also, CV was extracted from paper before and after different irradiation periods and analysed with HPLC-PDA. Photo-fading of CV on paper produced the same products as in solution, at least within the first 100 hours of irradiation. Finally, a photo-fading of CV in the presence of MK on Whatman paper was performed. It was demonstrated that MK both accelerates CV degradation and is consumed during the reaction. The degradation pathway identified in this work is suitable for explaining the photo/fading of other dyes belonging to the triarylmethane group.

  8. Investigation of Diamonds defects with Synchrotron Radiation Faculty

    Institute of Scientific and Technical Information of China (English)

    YuWanli; TIANYulian

    2001-01-01

    Infrared absorption measurements showed that the samples belong to type Ia variety of diamond and contained varying concentrations of A and B froms of nitrogen aggregates as well as platelets.The synchrotron radiation was employed to study the structure of these specimens.Growth bands are observed near the center of the crystals situated within(001)and (010) planes in high crystalline quality diamonds and the growth bads parallel to (100)and (010) cyrstalline plane.In the imperfect cystals low-angle boundaries are observed and the angles were determined to be larger than 2.5 degrees,The perfection of diamond crystals has no obvious relationship with the concentration of nitrogen.

  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. Quantum optical signal processing in diamond

    CERN Document Server

    Fisher, Kent A G; Maclean, Jean-Phillipe W; Bustard, Philip J; Resch, Kevin J; Sussman, Benjamin J

    2015-01-01

    Controlling the properties of single photons is essential for a wide array of emerging optical quantum technologies spanning quantum sensing, quantum computing, and quantum communications. Essential components for these technologies include single photon sources, quantum memories, waveguides, and detectors. The ideal spectral operating parameters (wavelength and bandwidth) of these components are rarely similar; thus, frequency conversion and spectral control are key enabling steps for component hybridization. Here we perform signal processing of single photons by coherently manipulating their spectra via a modified quantum memory. We store 723.5 nm photons, with 4.1 nm bandwidth, in a room-temperature diamond crystal; upon retrieval we demonstrate centre frequency tunability over 4.2 times the input bandwidth, and bandwidth modulation between 0.5 to 1.9 times the input bandwidth. Our results demonstrate the potential for diamond, and Raman memories in general, to be an integrated platform for photon storage ...

  11. Superhard BC(3) in cubic diamond structure.

    Science.gov (United States)

    Zhang, Miao; Liu, Hanyu; Li, Quan; Gao, Bo; Wang, Yanchao; Li, Hongdong; Chen, Changfeng; Ma, Yanming

    2015-01-01

    We solve the crystal structure of recently synthesized cubic BC(3) using an unbiased swarm structure search, which identifies a highly symmetric BC(3) phase in the cubic diamond structure (d-BC(3)) that contains a distinct B-B bonding network along the body diagonals of a large 64-atom unit cell. Simulated x-ray diffraction and Raman peaks of d-BC(3) are in excellent agreement with experimental data. Calculated stress-strain relations of d-BC(3) demonstrate its intrinsic superhard nature and reveal intriguing sequential bond-breaking modes that produce superior ductility and extended elasticity, which are unique among superhard solids. The present results establish the first boron carbide in the cubic diamond structure with remarkable properties, and these new findings also provide insights for exploring other covalent solids with complex bonding configurations.

  12. 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.

  13. Investigating the role of hydrogen in ultra-nanocrystalline diamond thin film growth

    Science.gov (United States)

    Birrell, James; Gerbi, J. E.; Auciello, O. A.; Carlisle, J. A.

    2006-08-01

    Hydrogen has long been known to be critical for the growth of high-quality microcrystalline diamond thin films as well as homoepitaxial single-crystal diamond. A hydrogen-poor growth process that results in ultra-nanocrystalline diamond thin films has also been developed, and it has been theorized that diamond growth with this gas chemistry can occur in the absence of hydrogen. This study investigates the role of hydrogen in the growth of ultra-nanocrystalline diamond thin films in two different regimes. First, we add hydrogen to the gas phase during growth, and observe that there seems to be a competitive growth process occurring between microcrystalline diamond and ultra-nanocrystalline diamond, rather than a simple increase in the grain size of ultra-nanocrystalline diamond. Second, we remove hydrogen from the plasma by changing the hydrocarbon precursor from methane to acetylene and observe that there does seem to be some sort of lower limit to the amount of hydrogen that can sustain ultra-nanocrystalline diamond growth. We speculate that this is due to the amount of hydrogen needed to stabilize the surface of the growing diamond nanocrystals.

  14. Large-acceptance diamond planar refractive lenses manufactured by laser cutting.

    Science.gov (United States)

    Polikarpov, Maxim; Snigireva, Irina; Morse, John; Yunkin, Vyacheslav; Kuznetsov, Sergey; Snigirev, Anatoly

    2015-01-01

    For the first time, single-crystal diamond planar refractive lenses have been fabricated by laser micromachining in 300 µm-thick diamond plates which were grown by chemical vapour deposition. Linear lenses with apertures up to 1 mm and parabola apex radii up to 500 µm were manufactured and tested at the ESRF ID06 beamline. The large acceptance of these lenses allows them to be used as beam-conditioning elements. Owing to the unsurpassed thermal properties of single-crystal diamond, these lenses should be suitable to withstand the extreme flux densities expected at the planned fourth-generation X-ray sources.

  15. Trace elements in sulfide inclusions from Yakutian diamonds

    Science.gov (United States)

    Bulanova, G. P.; Griffin, W. L.; Ryan, C. G.; Shestakova, O. Y.; Barnes, S.-J.

    1996-07-01

    Sulfide inclusions in diamonds may provide the only pristine samples of mantle sulfides, and they carry important information on the distribution and abundances of chalcophile elements in the deep lithosphere. Trace-element abundances were measured by proton microprobe in >50 sulfide inclusions (SDI) from Yakutian diamonds; about half of these were measured in situ in polished plates of diamonds, providing information on the spatial distribution of compositional variations. Many of the diamonds were identified as peridotitic or eclogitic from the nature of coexisting silicate or oxide inclusions. Known peridotitic diamonds contain SDIs with Ni contents of 22 36%, consistent with equilibration between olivine, monosulfide solid solution (MSS) and sulfide melt, whereas SDIs in eclogitic diamonds contain 0 12% Ni. A group of diamonds without silicate or oxide inclusions has SDIs with 11 18% Ni, and may be derived from pyroxenitic parageneses. Eclogitic SDIs have lower Ni, Cu and Te than peridotitic SDIs; the ranges of the two parageneses overlap for Se, As and Mo. The Mo and Se contents range up to 700 and 300 ppm, respectively; the highest levels are found in peridotitic diamonds. Among the in-situ SDIs, significant Zn and Pb levels are found in those connected by cracks to diamond surfaces, and these elements reflect interaction with kimberlitic melt. Significant levels of Ru (30 1300 ppm) and Rh (10 170 ppm) are found in many peridotitic SDIs; SDIs in one diamond with wustite and olivine inclusions and complex internal structures have high levels of other platinum-group elements (PGEs) as well, and high chondrite-normalized Ir/Pd. Comparison with experimental data on element partitioning between crystals of monosulfide solid solution (MSS) and sulfide melts suggests that most of the inclusions in both parageneses were trapped as MSS, while some high-Cu SDIs with high Pd±Rh may represent fractionated sulfide melts. Spatial variations of SDI composition within

  16. Investigation of Surface Magnetic Noise by Shallow Spins in Diamond

    NARCIS (Netherlands)

    Rosskopf, T; Dussaux, A; Ohashi, K; Loretz, M; Schirhagl, R; Watanabe, H; Shikata, S; Itoh, KM; Degen, CL

    2014-01-01

    We present measurements of spin relaxation times (T1, T1ρ, T2) on very shallow (≲5  nm) nitrogen-vacancy centers in high-purity diamond single crystals. We find a reduction of spin relaxation times up to 30 times compared to bulk values, indicating the presence of ubiquitous magnetic impurities asso

  17. 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...

  18. 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.

  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. Determination of output factor for 6 MV small photon beam: comparison between Monte Carlo simulation technique and microDiamond detector

    Science.gov (United States)

    Krongkietlearts, K.; Tangboonduangjit, P.; Paisangittisakul, N.

    2016-03-01

    In order to improve the life's quality for a cancer patient, the radiation techniques are constantly evolving. Especially, the two modern techniques which are intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) are quite promising. They comprise of many small beam sizes (beamlets) with various intensities to achieve the intended radiation dose to the tumor and minimal dose to the nearby normal tissue. The study investigates whether the microDiamond detector (PTW manufacturer), a synthetic single crystal diamond detector, is suitable for small field output factor measurement. The results were compared with those measured by the stereotactic field detector (SFD) and the Monte Carlo simulation (EGSnrc/BEAMnrc/DOSXYZ). The calibration of Monte Carlo simulation was done using the percentage depth dose and dose profile measured by the photon field detector (PFD) of the 10×10 cm2 field size with 100 cm SSD. Comparison of the values obtained from the calculations and measurements are consistent, no more than 1% difference. The output factors obtained from the microDiamond detector have been compared with those of SFD and Monte Carlo simulation, the results demonstrate the percentage difference of less than 2%.

  2. Broadly wavelength- and pulse width-tunable high-repetition rate light pulses from soliton self-frequency shifting photonic crystal fiber integrated with a frequency doubling crystal.

    Science.gov (United States)

    Lanin, Aleksandr A; Fedotov, Andrei B; Zheltikov, Aleksei M

    2012-09-01

    Soliton self-frequency shift (SSFS) in a photonic crystal fiber (PCF) pumped by a long-cavity mode-locked Cr:forsterite laser is integrated with second harmonic generation (SHG) in a nonlinear crystal to generate ultrashort light pulses tunable within the range of wavelengths from 680 to 1800 nm at a repetition rate of 20 MHz. The pulse width of the second harmonic output is tuned from 70 to 600 fs by varying the thickness of the nonlinear crystal, beam-focusing geometry, and the wavelength of the soliton PCF output. Wavelength-tunable pulses generated through a combination of SSFS and SHG are ideally suited for coherent Raman microspectroscopy at high repetition rates, as verified by experiments on synthetic diamond and polystyrene films.

  3. Characterization of a HPHT diamond detector for clinical applications

    Energy Technology Data Exchange (ETDEWEB)

    De Angelis, C., E-mail: cinzia.deangelis@iss.i [Department of Technology and Health, Istituto Superiore di Sanita Viale Regina Elena 299, 00161 Roma (Italy); Bucciolini, M. [Dipartimento di Fisiopatologia Clinica, Universita di Firenze (Italy); Viscomi, D. [Department of Technology and Health, Istituto Superiore di Sanita Viale Regina Elena 299, 00161 Roma (Italy); Marczewska, B. [IFJ, Institute of Nuclear Physics, Krakow (Poland); Onori, S. [Department of Technology and Health, Istituto Superiore di Sanita Viale Regina Elena 299, 00161 Roma (Italy)

    2010-01-11

    An investigation of a high-pressure high-temperature (HPHT) synthetic diamond detector was performed with the aim to evaluate the potentiality of the detector for use in IMRT beams. Dosimetric parameters such as dynamics, stability of the response, linearity with dose and dose-rate dependence were studied and the HPHT sample behaviour was compared with that of a PTW natural diamond used as a reference system. In addition, a test in IMRT field using the step-and-shoot technique was also carried out on HPHT device. The main result of this study was the fast response shown by the HPHT sample, comparable to that of the natural diamond. Nevertheless, strong dose-rate dependence and the presence of the overshoot still limit the use of this system.

  4. Diamonds are a chemist's best friend: diamondoid chemistry beyond adamantane.

    Science.gov (United States)

    Schwertfeger, Hartmut; Fokin, Andrey A; Schreiner, Peter R

    2008-01-01

    Marilyn Monroe knew that "diamonds are a girl's best friend" but, in the meantime, many chemists have realized that they are also extremely attractive objects in contemporary chemistry. The chemist's diamonds are usually quite small (herein: nanometer-sized "diamondoids") and as a result of their unique structure are unusual chemical building blocks. Since lower diamondoids (up to triamantane) have recently become available in large amounts from petroleum and higher diamondoids (starting from tetramantane) are now also accessible from crude oil new research involving them has begun to emerge. Having well-defined structures makes these cage compounds so special compared to other nanometer-scale diamonds. Selective and high-yielding synthetic approaches to the functionalization of diamondoids gives derivatives that can find applications in, for example, polymers, coating materials, drugs, and molecular electronics.

  5. 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.

  6. Anodic oxidation with doped diamond electrodes: a new advanced oxidation process

    Energy Technology Data Exchange (ETDEWEB)

    Kraft, Alexander; Stadelmann, Manuela; Blaschke, Manfred

    2003-10-31

    Boron-doped diamond anodes allow to directly produce OH{center_dot} radicals from water electrolysis with very high current efficiencies. This has been explained by the very high overvoltage for oxygen production and many other anodic electrode processes on diamond anodes. Additionally, the boron-doped diamond electrodes exhibit a high mechanical and chemical stability. Anodic oxidation with diamond anodes is a new advanced oxidation process (AOP) with many advantages compared to other known chemical and photochemical AOPs. The present work reports on the use of diamond anodes for the chemical oxygen demand (COD) removal from several industrial wastewaters and from two synthetic wastewaters with malic acid and ethylenediaminetetraacetic (EDTA) acid. Current efficiencies for the COD removal between 85 and 100% have been found. The formation and subsequent removal of by-products of the COD oxidation has been investigated for the first time. Economical considerations of this new AOP are included.

  7. 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...

  8. Inclusions of nanocrystalline hydrous aluminium silicate “Phase Egg” in superdeep diamonds from Juina (Mato Grosso State, Brazil)

    Science.gov (United States)

    Wirth, Richard; Vollmer, Christian; Brenker, Frank; Matsyuk, Stanislav; Kaminsky, Felix

    2007-07-01

    Inclusions in alluvial diamond from Juina (Mato Grosso, Brazil) have been investigated by TEM methods (electron diffraction, HRTEM, AEM, HAADF, EELS) and Raman spectroscopy. The inclusion paragenesis of Juina diamonds is dominated by ultrahigh-pressure ("superdeep") phases. One of these diamonds, sample #1.1/4, contains several micrometer-sized (approximately 200 μm by 50-70 μm) inclusions, which have been studied. TEM foils prepared applying Focused Ion Beam (FIB) technique revealed that these inclusions consist of a porous, nanocrystalline groundmass, which is composed of nanometre-sized crystals of a hydrous aluminium silicate phase with Al:Si approximately 1:1 and chemical composition of phase "Egg" (AlSiO 3(OH)), a minor volume fraction of nanocrystalline stishovite and pore space, which was originally filled with a fluid or gas. The nanocrystalline hydrous aluminium silicate phase is idiomorphic, randomly oriented (approximately 20-30 nm in size) predominantly with tetragonal crystal structure ( a0 = 0.743 nm, c0 = 0.706 nm). The monoclinic structure of synthetic phase "Egg" determined at ambient conditions [M.W. Schmidt, L.W. Finger, R.J. Ross, R.E. Dinnebier, Synthesis, crystal structure, and phase relations of AlSiO 3OH, a high-pressure hydrous phase, American Mineralogist 83 (1998) 881 - 888] is only occasionally observed. The fluid filling in the porosity has been released into the vacuum of the FIB during TEM specimen preparation. Quench products of the fluid containing minor concentrations of F- P- S- Cl- K- Ca and Ba were detected at the walls of the pores. In addition phase "Egg" is identified by μ-Raman spectroscopy within a second sample (RS 43a) from the same location. The presence of Phase "Egg" in the inclusions in diamond may suggest that crustal material has been subducted to a depth of the lower Transition Zone. Although, metastable growth of nanocrystalline high-pressure phases or extension of their respective stability fields to lower

  9. Novel phase of carbon, ferromagnetism, and conversion into diamond

    Energy Technology Data Exchange (ETDEWEB)

    Narayan, Jagdish, E-mail: narayan@ncsu.edu; Bhaumik, Anagh [Department of Materials Science and Engineering, Centennial Campus, North Carolina State University, Raleigh, North Carolina 27695-7907 (United States)

    2015-12-07

    We report the discovery of a new phase of carbon (referred to as Q-carbon) and address fundamental issues related to direct conversion of carbon into diamond at ambient temperatures and pressures in air without any need for catalyst and presence of hydrogen. The Q-carbon is formed as result of quenching from super undercooled state by using high-power nanosecond laser pulses. We discuss the equilibrium phase diagram (P vs. T) of carbon and show that by rapid quenching kinetics can shift thermodynamic graphite/diamond/liquid carbon triple point from 5000 K/12 GPa to super undercooled carbon at atmospheric pressure in air. It is shown that nanosecond laser heating of diamond-like amorphous carbon on sapphire, glass, and polymer substrates can be confined to melt carbon in a super undercooled state. By quenching the carbon from the super undercooled state, we have created a new state of carbon (Q-carbon) from which nanodiamond, microdiamond, microneedles, and single-crystal thin films are formed depending upon the nucleation and growth times allowed for diamond formation. The Q-carbon quenched from liquid is a new state of solid carbon with a higher mass density than amorphous carbon and a mixture of mostly fourfold sp{sup 3} (75%–85%) with the rest being threefold sp{sup 2} bonded carbon (with distinct entropy). It is expected to have new and improved mechanical hardness, electrical conductivity, chemical, and physical properties, including room-temperature ferromagnetism (RTFM) and enhanced field emission. Here we present interesting results on RTFM, enhanced electrical conductivity and surface potential of Q-carbon to emphasize its unique properties. The Q-carbon exhibits robust bulk ferromagnetism with estimated Curie temperature of about 500 K and saturation magnetization value of 20 emu g{sup −1}. From the Q-carbon, diamond phase is nucleated and a variety of micro- and nanostructures and large-area single-crystal diamond sheets are grown by allowing

  10. 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.

  11. Cobalt-related impurity centers in diamond: electronic properties and hyperfine parameters

    CERN Document Server

    Larico, R; Machado, W V M; Justo, J F

    2013-01-01

    Cobalt-related impurity centers in diamond have been studied using first principles calculations. We computed the symmetry, formation and transition energies, and hyperfine parameters of cobalt impurities in isolated configurations and in complexes involving vacancies and nitrogen atoms. We found that the Co impurity in a divacant site is energetically favorable and segregates nitrogen atoms in its neighborhood. Our results were discussed in the context of the recently observed Co-related electrically active centers in synthetic diamond.

  12. Microscopy of nitride layers grown on diamond

    DEFF Research Database (Denmark)

    Pécz, B.; Tóth, L.; Barna, Á.;

    2011-01-01

    are determined by selected area electron diffraction. Besides threading dislocations a high number of inversion domains (ID) were formed in some GaN films. The preparation of the diamond surface and the growth conditions proved to affect significantly the formation of crystal defects such as threading...... dislocations and IDs. Single polarity GaN films with a low density of dislocations were achieved for the optimized growth conditions. The highest quality GaN layers were grown on AlN buffer in which two crystalline variants were nucleated, but one of them was overgrown already in the thickness of the buffer...

  13. Long-term data storage in diamond

    Science.gov (United States)

    Dhomkar, Siddharth; Henshaw, Jacob; Jayakumar, Harishankar; Meriles, Carlos A.

    2016-01-01

    The negatively charged nitrogen vacancy (NV−) center in diamond is the focus of widespread attention for applications ranging from quantum information processing to nanoscale metrology. Although most work so far has focused on the NV− optical and spin properties, control of the charge state promises complementary opportunities. One intriguing possibility is the long-term storage of information, a notion we hereby introduce using NV-rich, type 1b diamond. As a proof of principle, we use multicolor optical microscopy to read, write, and reset arbitrary data sets with two-dimensional (2D) binary bit density comparable to present digital-video-disk (DVD) technology. Leveraging on the singular dynamics of NV− ionization, we encode information on different planes of the diamond crystal with no cross-talk, hence extending the storage capacity to three dimensions. Furthermore, we correlate the center’s charge state and the nuclear spin polarization of the nitrogen host and show that the latter is robust to a cycle of NV− ionization and recharge. In combination with super-resolution microscopy techniques, these observations provide a route toward subdiffraction NV charge control, a regime where the storage capacity could exceed present technologies.

  14. Kinetic equation for the reaction of titanium tetrachloride with hydride functional groups of diamond

    Energy Technology Data Exchange (ETDEWEB)

    Zhidkov, A.B.; Smirnov, E.P.

    1989-02-01

    This work is devoted to the study of the kinetics of the reaction of titanium tetrachloride with the hydride functional groups of diamond. The research was performed on submicron powders of ASM 0.7/0.3 grade synthetic diamond with a specific surface area of 8.0 m/sup 2//g as measured from the adsorption of nitrogen. The reaction was carried out in a flow-through quartz reactor in a flow of dry He. The content of the titanium in the samples was determined by a photocolorimetric method. A kinetic equation for the reaction of diamond with titanium tetrachloride was found on the basis of a statistical approach.

  15. 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.

  16. Optical hyperpolarization of nitrogen donor spins in bulk diamond

    Science.gov (United States)

    Loretz, M.; Takahashi, H.; Segawa, T. F.; Boss, J. M.; Degen, C. L.

    2017-02-01

    We report hyperpolarization of the electronic spins associated with substitutional nitrogen defects in bulk diamond crystals. Hyperpolarization is achieved by optical pumping of nitrogen vacancy centers followed by rapid cross relaxation at the energy level matching condition in a 51 mT bias field. The maximum observed donor spin polarization is 0.9 % , corresponding to an enhancement of 25 compared to the thermal Boltzmann polarization. A further accumulation of polarization is impeded by an anomalous optical saturation effect that we attribute to charge state conversion processes. Hyperpolarized nitrogen donors may form a useful resource for increasing the efficiency of diamond-based dynamic nuclear polarization devices.

  17. Transforming graphite to nanoscale diamonds by a femtosecond laser pulse

    Energy Technology Data Exchange (ETDEWEB)

    Nueske, R.; Jurgilaitis, A.; Enquist, H.; Harb, M.; Larsson, J. [Atomic Physics Division, Department of Physics, Lund University, P.O. Box 118, SE-221 00 Lund (Sweden); Fang, Y.; Haakanson, U. [Division of Solid State Physics/Nanometer Structure Consortium at Lund University, P.O. Box 118, S-221 00 Lund (Sweden); Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603-146, 100190 Beijing (China)

    2012-01-23

    Formation of cubic diamond from graphite following irradiation by a single, intense, ultra-short laser pulse has been observed. Highly oriented pyrolytic graphite (HOPG) samples were irradiated by a 100 fs pulse with a center wavelength of 800 nm. Following laser exposure, the HOPG samples were studied using Raman spectroscopy of the sample surface. In the laser-irradiated areas, nanoscale cubic diamond crystals have been formed. The exposed areas were also studied using grazing incidence x-ray powder diffraction showing a restacking of planes from hexagonal graphite to rhombohedral graphite.

  18. Study on the diamond/ultrafine WC-Co cermets interface formed in a SPS consolidated composite

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Nanocrystalline WC-Co composite powder and coated tungsten diamond by using vacuum vapor deposition were consolidated by the spark plasma sintering (SPS) process to prepare diamond-enhanced WC-Co cemented carbide composite materials. The interface microstructures between coated tungsten diamond and WC-Co cemented carbide matrix were investigated by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDXS). The results showed that there is a transitional layer between the diamond and the matrix, in which the carbon content is 62.97wt.%, and the content of cobalt in the transitional zone is 6.19wt.%; the content of cobalt in the WC-Co cemented carbide matrix is 6.07wt.%, in which the carbon content is 15.95wt.%, and the content of cobalt on the surface of diamond is 7.30wt.%, in which the carbon content is 80.38wt.%. The transitional zone prevents the carbon atom of the diamond from spreading to the matrix, in which the carbon content does coincide with the theoretical value of the raw nanocomposite powders, and the carbon content forms a graded distribution among the matrix, transitional zone, and the surface of diamond; after the 1280℃ SPS consolidated process the diamond still maintains a very good crystal shape, the coated tungsten on the surface of the diamond improves thermal stability of the diamond and increases the bonding strength of the interface between the diamond and the matrix.

  19. Non-destructive NIR-FT-raman analyses in practice. Part II. Analyses of 'jumping' crystals, photosensitive crystals and gems.

    Science.gov (United States)

    Andreev, G N; Schrader, B; Boese, R; Rademacher, P; von Cranach, L

    2001-12-01

    Using an improved sampling arrangement we observed the FT Raman spectra of the different phases of a 'jumping crystal', an inositol derivative. The phase transition produced--as consequences of large changes of the unit cell constants--changes in frequency and intensity mainly of CH deformation vibrations. Photochemical reactions, usually produced with light quanta in the visible range, are not activated with the quanta from the Nd:YAG laser at 1064 nm. The Raman spectra of the 'dark' form of a dinitrobenzyl pyridine and afterwards the 'light' form, the product of its illumination in the visible range, were recorded. We could not observe changes of most bands, especially not of the NO2-vibrations; however, a new strong band appeared at 1253 cm(-1), which may be due to the expected NH-photo-isomer. Genuine gemstones and fakes can be unambiguously identified by FT Raman spectroscopy. This is especially useful for the stones whose physical properties are quite similar to those of diamonds--moissanite and zirconia. The quality of diamonds can be estimated from relative band intensities; however, this is not in complete agreement with the internationally accepted visual qualification. Synthetic diamonds produced by CVD (chemical vapor deposition) show remarkable differences from natural ones in their FT-Raman spectra.

  20. Band alignment and defects of the diamond zinc oxide heterojunction; Bandstruktur und Defekte der Diamant-Zinkoxid-Heterostruktur

    Energy Technology Data Exchange (ETDEWEB)

    Geithner, Peter

    2008-09-12

    Zinc oxide films were grown on diamond single crystals by rf sputtering of zinc oxide. The valence and conduction band offset was determined by photoelectron spectroscopy. A deep defect occurring in the zinc oxide films on diamond was characterized by cathodoluminescence spectroscopy. (orig.)

  1. 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 ...

  2. 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...

  3. 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...

  4. New finding of micro-diamonds in eclogites from Dabie-Sulu region in central-eastern China

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Micro-diamonds were only found ten years ago in eclogite associated with marble at Xindian in the Dabie Mountains. This paper reports our new finding of micro-diamonds not only in eclogites at Maobei in the Sulu region and at Xindian and Laoyoufang in the south part of the Dabie Mountains (South Dabie), but also in eclogites at Baizhangya and Huangweihe in the northern part of the Dabie Mountains (North Dabie) that has usually been considered not to experience ultrahigh pressure metamorphism. Except the micro-diamond at Huangweihe that was found from the artificial heavy sands of zircons used for isotopic dating, the micro-diamonds from other localities were identified in thin sections of the eclogites. Besides a few interstitial grains, most of the micro-diamond grains in thin sections occur as inclusion in garnet. Three crystals of micro- diamond at Maobei in the Sulu region are sized in 120, 60 and 30 (m, respectively. Crystal forms look like octahedron and the composite of octahedron and hexahedron. The largest micro-diamond crystal comes from Xindian, which is measured to be 180 (m in diameter with distinct zonal structure and inclusions. The zonal structure occurs as an inclined octahedron inside rounded by an incomplete hexagonal girdle. A smaller micro-diamond inclusion occurs inside the central octahedron, and a larger graphite inclusion is within the outer zone. The Laoyoufang micro-diamond is partially retrograded to graphite. Micro-diamond from the Baizhangya eclogite in the ultramafic rock belt of North Dabie is an aggregate of 70 (m×90 (m in size. All the micro-diamonds are confirmed by the Raman spectrum analysis. The occurrence of the micro-diamonds from the eclogites in the ultramafic rock belt of North Dabie demonstrates that this region was also subjected to ultrahigh pressure metamorphism as well as the South Dabie did.

  5. 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.

  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. Determination of L- and D-fucose using amperometric electrodes based on diamond paste.

    Science.gov (United States)

    Stefan-van Staden, Raluca-Ioana; Nejem, R'afat Mahmoud; van Staden, Jacobus Frederick; Aboul-Enein, Hassan Y

    2012-02-21

    Monocrystalline diamond (natural diamond, synthetic-1 and synthetic-2) based electrochemical electrodes were designed for the analysis of L- and D-fucose. Response characteristics of the electrochemical electrodes were determined using cyclic voltammetry and differential pulse voltammetry (DPV). L-fucose was determined using DPV with electrodes based on natural diamond, synthetic-1 and synthetic-2, respectively, at 240 mV using NaCl as the electrolyte (pH 3.0); at 160 mV using KNO(3) (pH 10.0) and at 80 mV using KCl as the electrolyte (pH 10.0) while D-fucose was analyzed at 120 mV using KCl as the electrolyte (pH 1.0); at 140 mV using KNO(3) as the electrolyte (pH 1.0) and at 160 mV using NaNO(3) as the electrolyte (pH 3.0). The linear concentration ranges for L-fucose were between 10(-13) and 10(-9) mol L(-1) (natural diamond), 10(-11) and 10(-8) mol L(-1) (synthetic-1) and 10(-6) and 10(-3) mol L(-1) (synthetic-2) with detection limits of 10(-14), 10(-12) and 10(-8) mol L(-1) magnitude order, respectively. For D-fucose, the linear concentration ranges were 10(-6) to 10(-3) mol L(-1) (natural diamond), 10(-5) to 10(-3) mol L(-1) (synthetic-1) and 10(-9) to 10(-3) mol L(-1) (synthetic-2) with detection limits of 10(-7), 10(-7) and 10(-10) mol L(-1) magnitude order, respectively. The sensors were used for the assay of L-fucose in serum and urine samples.

  8. Diamond resorption features as a new method for examining conditions of kimberlite emplacement

    Science.gov (United States)

    Fedortchouk, Yana

    2015-10-01

    The study develops a new approach utilizing parameters of trigonal etch pits on diamond crystals to infer the conditions of diamond residence in kimberlite magma. Diamond crystals from dissolution experiments conducted at 1 GPa and 1150-1350 °C in the presence of H2O-rich or CO2-rich fluid were studied with atomic force microscopy (AFM). The AFM data of resorbed diamond surfaces show that much deeper surface relief was produced in CO2 fluid. It also clearly distinguishes the profiles of the trigonal etch pits forming regular flat-bottomed trigons in H2O fluid, and round- or pointed-bottomed trigons in CO2 fluid. The relationship between the diameter and the depth of the trigonal pits is found to be another important indicator of the fluid composition. Dissolution in H2O fluid develops trigons with constant diameter and variable depth where the diameter increases with temperature. Trigons developed in CO2 fluid have a large range of diameters showing a strong positive correlation with the depth. The developed criteria applied to the natural diamond crystals from three Ekati Mine kimberlites indicate significant variation in CO2-H2O ratio and temperature of their magmatic fluid. This conclusion based on diamond resorption agrees with the mineralogy of microphenocrysts and groundmass of the studied kimberlites offering new method to study crystallization conditions of kimberlite magma.

  9. Large gem diamonds from metallic liquid in Earth's deep mantle.

    Science.gov (United States)

    Smith, Evan M; Shirey, Steven B; Nestola, Fabrizio; Bullock, Emma S; Wang, Jianhua; Richardson, Stephen H; Wang, Wuyi

    2016-12-16

    The redox state of Earth's convecting mantle, masked by the lithospheric plates and basaltic magmatism of plate tectonics, is a key unknown in the evolutionary history of our planet. Here we report that large, exceptional gem diamonds like the Cullinan, Constellation, and Koh-i-Noor carry direct evidence of crystallization from a redox-sensitive metallic liquid phase in the deep mantle. These sublithospheric diamonds contain inclusions of solidified iron-nickel-carbon-sulfur melt, accompanied by a thin fluid layer of methane ± hydrogen, and sometimes majoritic garnet or former calcium silicate perovskite. The metal-dominated mineral assemblages and reduced volatiles in large gem diamonds indicate formation under metal-saturated conditions. We verify previous predictions that Earth has highly reducing deep mantle regions capable of precipitating a metallic iron phase that contains dissolved carbon and hydrogen.

  10. Selective-Area Growth of Thick Diamond Films Using Chemically Stable Masks of Ru/Au and Mo/Au

    Science.gov (United States)

    Nagase, Masanori; Watanabe, Katsumi; Umezawa, Hitoshi; Shikata, Shinichi

    2012-07-01

    Selective-area growth of diamond films in microwave-plasma chemical vapor deposition was performed using newly developed masks. By forming chemically stable masks made of Ru/Au or Mo/Au, which have high melting points, good adhesion to diamond, and difficulty in forming carbide compounds, patterned diamond films with a large thickness of 50 µm, a large area of 5 mm2, and a high orientation in the [001] direction were successfully grown on (001) diamond substrates without degradation of the crystal quality of masked areas.

  11. 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.

  12. Fabrication of UV Photodetector on TiO2/Diamond Film.

    Science.gov (United States)

    Liu, Zhangcheng; Li, Fengnan; Li, Shuoye; Hu, Chao; Wang, Wei; Wang, Fei; Lin, Fang; Wang, Hongxing

    2015-09-24

    The properties of ultraviolet (UV) photodetector fabricated on TiO2/diamond film were investigated. Single crystal diamond layer was grown on high-pressure-high-temperature Ib-type diamond substrate by microwave plasma chemical vapor deposition method, upon which TiO2 film was prepared directly using radio frequency magnetron sputtering technique in Ar and O2 mixing atmosphere. Tungsten was used as electrode material to fabricate metal-semiconductor-metal UV photodetector. The dark current is measured to be 1.12 pA at 30 V. The photo response of the device displays an obvious selectivity between UV and visible light, and the UV-to-visible rejection ratio can reach 2 orders of magnitude. Compared with that directly on diamond film, photodetector on TiO2/diamond film shows higher responsivity.

  13. 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.

  14. 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.)

  15. 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.

  16. Source assemblage types for cratonic diamonds from X-ray synchrotron diffraction

    Science.gov (United States)

    Nestola, F.; Alvaro, M.; Casati, M. N.; Wilhelm, H.; Kleppe, A. K.; Jephcoat, A. P.; Domeneghetti, M. C.; Harris, J. W.

    2016-11-01

    Three single crystals of clinopyroxene trapped within three different gem-quality diamonds from the Udachnaya kimberlite (Siberia, Russia) were analysed in situ by single-crystal synchrotron X-ray diffraction in order to obtain information on their chemical composition and infer source assemblage type. A non-destructive approach was used with high-energy (≈ 60 keV; λ ≈ 0.206 Å) at I15, the extreme-conditions beamline at Diamond Light Source. A dedicated protocol was used to center the mineral inclusions located deep inside the diamonds in the X-ray beam. Our results reveal that two of the inclusions can be associated with peridotitic paragenesis whereas the third is eclogitic. This study also demonstrates that this non-destructive experimental approach is extremely efficient in evaluating the origin of minerals trapped in their diamond hosts.

  17. 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.

  18. A New Dopant of NaN3 for High-Concentration-Nitrogen Diamond Synthesized by HPHT

    Institute of Scientific and Technical Information of China (English)

    LIANG Zhong-Zhu; JIA Xiao-Peng; Hisao Kan-da; MA Hong-An; WANG Dong-Mei; LIU Wan-Qiang; YU Run-Ze

    2007-01-01

    Nitrogen is successfully doped in diamond by adding sodium azide (NaN3) as the source of nitrogen to the graphite and iron powders. The diamond crystals with high nitrogen concentration, 1000-2200 ppm, which contain the same concentrations of nitrogen with natural diamond, have been synthesized by using the system of iron-carbonadditive NaN3. The nitrogen concentrations in diamond increase with the increasing content of NaN3. When the content of NaN3 is increased to 0.7-1.3 wt.%, the nitrogen concentration in the diamond almost remains in a nitrogen concentration range from 1250 ppm to 2200 ppm, which is the highest value and several times higher than that in the diamond synthesized by a conventional method without additive NaN3 under high pressure and high temperature (HPHT) conditions.

  19. Level-crossing spectroscopy of nitrogen-vacancy centers in diamond: sensitive detection of paramagnetic defect centers

    CERN Document Server

    Anishchik, S V; Ivanov, K L

    2016-01-01

    We report a magnetic field dependence of fluorescence of diamond single crystals containing NV$^-$ centers. In such spectra, numerous sharp lines are found, which correspond to Level Anti-Crossings (LACs) in coupled spins systems comprising an NV$^-$ center. Theoretical modeling of such "LAC-spectra" enables characterization of paramagnetic defect centers and determination of their magnetic resonance parameters, such as zero-field splitting and hyperfine coupling constants. The outlined method thus enables sensitive detection of paramagnetic impurities in diamond crystals.

  20. Results on the Coherent Interaction of High Energy Electrons and Photons in Oriented Single Crystals

    CERN Document Server

    Apyan, A; Badelek, B; Ballestrero, S; Biino, C; Birol, I; Cenci, P; Connell, S H; Eichblatt, S; Fonseca, T; Freund, A; Gorini, B; Groess, R; Ispirian, K; Ketel, T; Kononets, Y V; López, A; Mangiarotti, A; Van Rens, B; Sellschop, J P Friedel; Shieh, M; Sona, P; Strakhovenko, V M; Uggerhøj, Erik; Uggerhøj, U; Ünel, G; Velasco, M; Vilakazi, Z Z; Wessely, O; Kononets, Yu.V.

    2005-01-01

    The CERN-NA-59 experiment examined a wide range of electromagnetic processes for multi-GeV electrons and photons interacting with oriented single crystals. The various types of crystals and their orientations were used for producing photon beams and for converting and measuring their polarisation. The radiation emitted by 178 GeV unpolarised electrons incident on a 1.5 cm thick Si crystal oriented in the Coherent Bremsstrahlung (CB) and the String-of-Strings (SOS) modes was used to obtain multi-GeV linearly polarised photon beams. A new crystal polarimetry technique was established for measuring the linear polarisation of the photon beam. The polarimeter is based on the dependence of the Coherent Pair Production (CPP) cross section in oriented single crystals on the direction of the photon polarisation with respect to the crystal plane. Both a 1 mm thick single crystal of Germanium and a 4 mm thick multi-tile set of synthetic Diamond crystals were used as analyzers of the linear polarisation. A birefringence ...

  1. 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.

  2. 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.

  3. 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.

  4. NCD Diamond Semiconductor System for Advanced Power Electronics Systems Integration : CRADA report

    Energy Technology Data Exchange (ETDEWEB)

    Sumant, Anirudha [AKHAN Semiconductor, Inc., Hoffman Estates, IL (United States)

    2016-07-22

    The integration of 2D materials such as molybdenum disulphide (MoS2) with diamond (3D) was achieved by forming an heterojunction between these two materials and its electrical performance was studied experimentally. The device charactertics did show good rectifying nature when p-type single crystal diamond was integrated with n-type MoS2. These results are very encouraging indicating possible applications in semiconductor electronics, however further studies are required for a detailed understanding of the transport phenomena at the MoS2/diamond interface.

  5. High-temperature Superconductivity in Diamond Films - from Fundamentals to Device Applications

    Science.gov (United States)

    2014-12-20

    AND ADDRESS(ES) University of Melbourne Corner Swanston St. and Tin Alley Parkville, VIC Australia 8. PERFORMING ORGANIZATION REPORT...investigated the feasibility of ion implanting diamond plates with boron to create highly conducting, sub-surface layers. These layers hold great...implanted 2 MeV boron (B) ions into type-IIa diamond plates (followed by high temperature annealing to repair crystal damage) to create heavily doped

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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...

  12. Laser writing of coherent colour centres in diamond

    CERN Document Server

    Chen, Yu-Chen; Knauer, Sebastian; Weng, Laiyi; Frangeskou, Angelo C; Stephen, Colin J; Dolan, Philip R; Johnson, Sam; Green, Ben L; Morley, Gavin W; Newton, Mark E; Rarity, John G; Booth, Martin J; Smith, Jason M

    2016-01-01

    Optically active point defects in crystals have gained widespread attention as photonic systems that can find use in quantum information technologies. However challenges remain in the placing of individual defects at desired locations, an essential element of device fabrication. Here we report the controlled generation of single nitrogen-vacancy (NV) centres in diamond using laser writing. The use of aberration correction in the writing optics allows precise positioning of vacancies within the diamond crystal, and subsequent annealing produces single NV centres with up to 45% success probability, within about 200 nm of the desired position. Selected NV centres fabricated by this method display stable, coherent optical transitions at cryogenic temperatures, a pre-requisite for the creation of distributed quantum networks of solid-state qubits. The results illustrate the potential of laser writing as a new tool for defect engineering in quantum technologies.

  13. New route to the fabrication of nanocrystalline diamond films

    Science.gov (United States)

    Varshney, Deepak; Palomino, Javier; Gil, Jennifer; Resto, Oscar; Weiner, Brad R.; Morell, Gerardo

    2014-02-01

    Nanocrystalline diamond (NCD) thin films offer applications in various fields, but the existing synthetic approaches are cumbersome and destructive. A major breakthrough has been achieved by our group in the direction of a non-destructive, scalable, and economic process of NCD thin-film fabrication. Here, we report a cheap precursor for the growth of nanocrystalline diamond in the form of paraffin wax. We show that NCD thin films can be fabricated on a copper support by using simple, commonplace paraffin wax under reaction conditions of Hot Filament Chemical Vapor Deposition (HFCVD). Surprisingly, even the presence of any catalyst or seeding that has been conventionally used in the state-of-the-art is not required. The structure of the obtained films was analyzed by scanning electron microscopy and transmission electron microscopy. Raman spectroscopy and electron energy-loss spectroscopy recorded at the carbon K-edge region confirm the presence of nanocrystalline diamond. The process is a significant step towards cost-effective and non-cumbersome fabrication of nanocrystalline diamond thin films for commercial production.

  14. New route to the fabrication of nanocrystalline diamond films

    Energy Technology Data Exchange (ETDEWEB)

    Varshney, Deepak, E-mail: deepvar20@gmail.com; Morell, Gerardo [Institute of Functional Nanomaterials, University of Puerto Rico, San Juan, Puerto Rico 00931, Puerto Rico (United States); Department of Physics, University of Puerto Rico, San Juan, PO Box 70377, Puerto Rico 00936, Puerto Rico (United States); Palomino, Javier; Resto, Oscar [Department of Physics, University of Puerto Rico, San Juan, PO Box 70377, Puerto Rico 00936, Puerto Rico (United States); Gil, Jennifer [Department of Chemistry, University of Puerto Rico, San Juan, Puerto Rico 00936, Puerto Rico (United States); Weiner, Brad R. [Institute of Functional Nanomaterials, University of Puerto Rico, San Juan, Puerto Rico 00931, Puerto Rico (United States); Department of Chemistry, University of Puerto Rico, San Juan, Puerto Rico 00936, Puerto Rico (United States)

    2014-02-07

    Nanocrystalline diamond (NCD) thin films offer applications in various fields, but the existing synthetic approaches are cumbersome and destructive. A major breakthrough has been achieved by our group in the direction of a non-destructive, scalable, and economic process of NCD thin-film fabrication. Here, we report a cheap precursor for the growth of nanocrystalline diamond in the form of paraffin wax. We show that NCD thin films can be fabricated on a copper support by using simple, commonplace paraffin wax under reaction conditions of Hot Filament Chemical Vapor Deposition (HFCVD). Surprisingly, even the presence of any catalyst or seeding that has been conventionally used in the state-of-the-art is not required. The structure of the obtained films was analyzed by scanning electron microscopy and transmission electron microscopy. Raman spectroscopy and electron energy-loss spectroscopy recorded at the carbon K-edge region confirm the presence of nanocrystalline diamond. The process is a significant step towards cost-effective and non-cumbersome fabrication of nanocrystalline diamond thin films for commercial production.

  15. Experimental determination of third-order elastic constants of diamond.

    Science.gov (United States)

    Lang, J M; Gupta, Y M

    2011-03-25

    To determine the nonlinear elastic response of diamond, single crystals were shock compressed along the [100], [110], and [111] orientations to 120 GPa peak elastic stresses. Particle velocity histories and elastic wave velocities were measured by using laser interferometry. The measured elastic wave profiles were used, in combination with published acoustic measurements, to determine the complete set of third-order elastic constants. These constants represent the first experimental determination, and several differ significantly from those calculated by using theoretical models.

  16. Theory and modelling of diamond fracture from an atomic perspective.

    Science.gov (United States)

    Brenner, Donald W; Shenderova, Olga A

    2015-03-28

    Discussed in this paper are several theoretical and computational approaches that have been used to better understand the fracture of both single-crystal and polycrystalline diamond at the atomic level. The studies, which include first principles calculations, analytic models and molecular simulations, have been chosen to illustrate the different ways in which this problem has been approached, the conclusions and their reliability that have been reached by these methods, and how these theory and modelling methods can be effectively used together.

  17. Plasmonic resonators for enhanced diamond NV- center single photon sources

    OpenAIRE

    Bulu, Irfan; Babinec, Thomas; Hausmann, Birgit; Choy, Jennifer T.; Loncar, Marko

    2011-01-01

    We propose a novel source of non-classical light consisting of plasmonic aperture with single-crystal diamond containing a single Nitrogen-Vacancy (NV) color center. Theoretical calculations of optimal structures show that these devices can simultaneously enhance optical pumping by a factor of 7, spontaneous emission rates by Fp ~ 50 (Purcell factor), and offer collection efficiencies up to 40%. These excitation and collection enhancements occur over a broad range of wavelengths (~30nm), and ...

  18. Synthetic environments

    Science.gov (United States)

    Lukes, George E.; Cain, Joel M.

    1996-02-01

    The Advanced Distributed Simulation (ADS) Synthetic Environments Program seeks to create robust virtual worlds from operational terrain and environmental data sources of sufficient fidelity and currency to interact with the real world. While some applications can be met by direct exploitation of standard digital terrain data, more demanding applications -- particularly those support operations 'close to the ground' -- are well-served by emerging capabilities for 'value-adding' by the user working with controlled imagery. For users to rigorously refine and exploit controlled imagery within functionally different workstations they must have a shared framework to allow interoperability within and between these environments in terms of passing image and object coordinates and other information using a variety of validated sensor models. The Synthetic Environments Program is now being expanded to address rapid construction of virtual worlds with research initiatives in digital mapping, softcopy workstations, and cartographic image understanding. The Synthetic Environments Program is also participating in a joint initiative for a sensor model applications programer's interface (API) to ensure that a common controlled imagery exploitation framework is available to all researchers, developers and users. This presentation provides an introduction to ADS and the associated requirements for synthetic environments to support synthetic theaters of war. It provides a technical rationale for exploring applications of image understanding technology to automated cartography in support of ADS and related programs benefitting from automated analysis of mapping, earth resources and reconnaissance imagery. And it provides an overview and status of the joint initiative for a sensor model API.

  19. 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.

  20. Correlated carbon and oxygen isotope signatures in eclogitic diamonds with coesite inclusions: A SIMS investigation of diamonds from Guaniamo, Argyle and Orapa mines

    Science.gov (United States)

    Schulze, D. J.; Page, Z.; Harte, B.; Valley, J.; Channer, D.; Jaques, L.

    2006-12-01

    Using ion microprobes and secondary-ion mass spectrometry we have analyzed the carbon and oxygen isotopic composition of eclogite-suite diamonds and their coesite inclusions, respectively, from three suites of diamonds of Proterozoic age. Extremely high (for the mantle) oxygen isotope values (delta 18O of +10.2 to +16.9 per mil VSMOW) are preserved in coesites included in eclogitic diamonds from Guaniamo, Venezuela (Schulze et al., Nature, 2003), providing compelling evidence for an origin of their eclogite hosts by subduction of sea water altered ocean floor basalts. In situ SIMS analyses of their host diamonds yield carbon isotope values (delta 13C) of -12 to -18 per mil PDB. SIMS analyses of coesite inclusions from Argyle, Australia diamonds previously analyzed by combustion methods for d13C composition (Jaques et al., Proc. 4th Kimb. Conf, 1989), also yield anomalously high d18O values (+6.8 to +16.0 per mil VSMOW), that correlate with the anomalously low carbon isotope values (-10.3 to -14.1 per mil PDB). One coesite-bearing diamond from Orapa, Botswana analyzed in situ by SIMS has a d18O value of the coesite of +8.5 per mil VSMOW and a d13C value of the adjacent diamond host of -9.0 per mil PDB. A second Orapa stone has a SIMS carbon isotope compositional range of d13C = -14 to -16 per mil PDB, but the coesite is too small for ion probe analysis. At each of these localities, carbon isotope values of coesite-bearing diamonds that are lower than typical of mantle carbon are correlated with oxygen isotope compositions of included coesites that are substantially above the common mantle oxygen isotope range. Such results are not in accord with diamond genesis models involving formation of eclogitic diamonds from igneous melts undergoing fractionation in the mantle or by crystallization from primordial inhomogeneities in Earth's mantle. By analogy with the oxygen isotope compositions of altered ocean floor basalts and Alpine (subduction zone) eclogites they are

  1. The Development of Open Water-lubricated Polycrystalline Diamond (PCD) Thrust Bearings for Use in Marine Hydrokinetic (MHK) Energy Machines

    Energy Technology Data Exchange (ETDEWEB)

    Cooley, Craig, H.; Khonsari, Michael,, M; Lingwall, Brent

    2012-11-28

    Polycrstalline diamond (PCD) bearings were designed, fabricated and tested for marine-hydro-kinetic (MHK) application. Bearing efficiency and life were evaluated using the US Synthetic bearing test facility. Three iterations of design, build and test were conducted to arrive at the best bearing design. In addition life testing that simulated the starting and stopping and the loading of real MHK applications were performed. Results showed polycrystalline diamond bearings are well suited for MHK applications and that diamond bearing technology is TRL4 ready. Based on life tests results bearing life is estimated to be at least 11.5 years. A calculation method for evaluating the performance of diamond bearings of round geometry was also investigated and developed. Finally, as part of this effort test bearings were supplied free of charge to the University of Alaska for further evaluation. The University of Alaska test program will subject the diamond bearings to sediment laden lubricating fluid.

  2. Valance electron structure of carbide-diamond interface and catalytic mechanism for diamond synthesis under high-pressure and high-temperature

    Institute of Scientific and Technical Information of China (English)

    GONG Jianhong; XU Bin; YIN Longwei; QI Yongxin; LI Li; SU Qingcai; LI Musen

    2006-01-01

    The metallic films surrounding a synthetic diamond formed under high-pressure and high-temperature (HPHT) in the presence of Fe-based and Ni-based catalysts were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). It was showed that the carbide was the primary carbon source for the nucleation and growth of diamond. Based on the EET (empirical electron theory in solid and molecules) theory, the valence electron structure of interface between carbide (Fe3C, Ni3C, (Fe, Ni)3C) and diamond was calculated using the bonding length difference (BLD) method. The boundary criterion of Thomas-Fermi-Dirac-Cheng (TFDC): "the electron density being equal on the contacting surfaces of atoms" was applied to analyze the valence structure of carbide-diamond interface. The result based on the calculation valance electron structure is in good accordance with the experimental result. This study is very helpful to reveal the catalytic mechanism of diamond nucleation and growth and design the new catalyst for diamond synthesis.

  3. A Study of Diamond Growth Instability t High Temperature-High Pressure

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In this paper, crystal growth instability of diamond was studied in a Fe-Ni-C system at high temperature-high pressure (HPHT). As any other crystal grown from solution, the flat or smooth growth interface of the diamond crystal is highly sensitive to growth conditions. The growth front interface should be of great importance to understand the diamond growth process. The presence of cellular growth interface by transmission electron microscopy indicated that there existed a narrow constitutional supercooling zone in front of the growth interface. Several parallel layers with cellular interface by TEM directly suggested that the diamond grows from the solution of carbon in the molten catalyst layer by layer, which is in accordance with the result obtained by scanning electron microscopy in this paper.Impurities are trapped by rapidly advancing growth layers during the diamond growth and they impose a great effect on the growth front stability. As the growth front interface approaches the impurity particle to a distance of about 10-5~10-7 cm, appreciable molecular forces begin to operate between them, and the impurity particle is trapped as the growth rate reaches a critical value. As a result, the driving force for crystallization under the impurity particles becomes smaller, the front buckles under the particle. An impurity naturally reduces the growth rate to a different extent.

  4. Synthetic foldamers.

    Science.gov (United States)

    Guichard, Gilles; Huc, Ivan

    2011-06-07

    Foldamers are artificial folded molecular architectures inspired by the structures and functions of biopolymers. This highlight focuses on important developments concerning foldamers produced by chemical synthesis and on the perspectives that these new self-organized molecular scaffolds offer. Progress in the field has led to synthetic objects that resemble small proteins in terms of size and complexity yet that may not contain any α-amino acids. Foldamers have introduced new tools and concepts to develop biologically active substances, synthetic receptors and novel materials.

  5. Decrease of FIB-induced lateral damage for diamond tool used in nano cutting

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Wei [State Key Laboratory of Precision Measuring Technology and Instruments, Centre of MicroNano Manufacturing Technology, Tianjin University, Tianjin 300072 (China); Xu, Zongwei, E-mail: zongweixu@163.com [State Key Laboratory of Precision Measuring Technology and Instruments, Centre of MicroNano Manufacturing Technology, Tianjin University, Tianjin 300072 (China); Fang, Fengzhou, E-mail: fzfang@gmail.com [State Key Laboratory of Precision Measuring Technology and Instruments, Centre of MicroNano Manufacturing Technology, Tianjin University, Tianjin 300072 (China); Liu, Bing; Xiao, Yinjing; Chen, Jinping [State Key Laboratory of Precision Measuring Technology and Instruments, Centre of MicroNano Manufacturing Technology, Tianjin University, Tianjin 300072 (China); Wang, Xibin [School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081 (China); Liu, Hongzhong [State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049 (China)

    2014-07-01

    Highlights: • We mainly aim to characterize and decrease the FIB-induced damage on diamond tool. • Raman and XPS methods were used to characterize the nanoscale FIB-induced damage. • Lower energy FIB can effectively lessen the FIB-induced damage on diamond tool. • The diamond tools’ performance was greatly improved after FIB process optimization. • 6 nm chip thickness of copper was achieved by diamond tool with 22 nm edge radius. - Abstract: Diamond cutting tools with nanometric edge radius used in ultra-precision machining can be fabricated by focused ion beam (FIB) technology. However, due to the nanoscale effects, the diamond tools performance and the cutting edge lifetime in nano cutting would be degraded because of the FIB-induced nanoscale lateral damage. In this study, the methods of how to effectively characterize and decrease the FIB-induced lateral damage for diamond tool are intensively studied. Based on the performance optimization diamond machining tools, the controllable chip thickness of less than 10 nm was achieved on a single-crystal copper in nano cutting. In addition, the ratio of minimum thickness of chip (MTC) to tool edge radius of around 0.3–0.4 in nano cutting is achieved. Methods for decreasing the FIB-induced damage on diamond tools and adding coolant during the nano cutting are very beneficial in improving the research of nano cutting and MTC. The nano cutting experiments based on the sharp and high performance of diamond tools would validate the nano cutting mechanisms that many molecular dynamic simulation studies have put forward and provide new findings for nano cutting.

  6. Understanding the source: The nitrogen isotope composition of Type II mantle diamonds

    Science.gov (United States)

    Mikhail, Sami; Howell, Dan; Jones, Adrian; Milledge, Judith; Verchovsky, Sasha

    2010-05-01

    Diamonds can be broadly subdivided into 2 groups based on their nitrogen content; type I with > 10ppm nitrogen and type II with growth nitrogen can be incorporated into diamond as a compatible element in a closed system and therefore the N/C ratio in the source can be depleted by Rayleigh fractionation as the first diamonds to crystallise will partition nitrogen atoms into their lattice as a 1:1 substitution for carbon atoms (type I diamonds). However nitrogen may behave as an incompatible element in diamond (and be a compatible element in the metasomatic fluid), this coupled with an open system would lead to the removal of nitrogen by the metasomatic fluids, thus causing the source to progressively become depleted in nitrogen. Continued diamond crystallization in either system will produce diamonds with ever decreasing nitrogen concentrations with time, possibly to the point of them being almost nitrogen free. 2- It is conceivable that type I & II diamonds found in the same deposit and sharing a common paragenesis (eclogitic or peridotitic) may have formed from different metasomatic fluids in separate diamond forming events. The latter has been proposed for samples from the Cullinan mine (South Africa) based on their carbon isotope compositions (3). Both models can be tested using the stable isotope compositions of carbon and nitrogen with the N/C ratio of the diamonds in a given population with varying nitrogen content (from type I to type II). 1.D. G. Pearson, D. Canil, S. B. Shirey, D. H. Heinrich, K. T. Karl, in Treatise on Geochemistry. (Pergamon, Oxford, 2003), pp. 171-275. 2.C. McCammon, Science 293, 813 (August 3, 2001, 2001). 3.A. E. Moore, South African Journal of Geology 112, 23 (March 1, 2009, 2009).

  7. 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,

  8. New sapphire and ruby components and their manufacture using diamond abrasives

    Science.gov (United States)

    Sauser, D.

    The properties of synthetic aluminum oxides (sapphire and ruby) and their applications in watchmaking (watch bearings and watchglasses) and as hard-wearing components such as centering devices for optical fibres and water jet nozzles for material cutting are discussed. Examples are given of the use of diamonds tools for machining such components, including sawing, drilling, grinding and polishing operations.

  9. 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...

  10. 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.

  11. Kinetic study of isothermal crystallization process of Gd2Ti2O7 precursor's powder prepared through the Pechini synthetic approach

    Science.gov (United States)

    Janković, Bojan; Marinović-Cincović, Milena; Dramićanin, Miroslav

    2015-10-01

    Crystallization process of Gd2Ti2O7 precursor's powder prepared by Pechini-type polymerized complex route has been studied under isothermal experimental conditions in an air atmosphere. It was found that the crystallization proceeds through two-parameter Šesták-Berggren (SB) autocatalytic model, in the operating temperature range of 550 °C≤T≤750 °C. Based on the behavior of SB parameters (M, N), it was found that in the lower operating temperature range, the crystallites with relatively low compactness exist, which probably disclosed low dimensionality of crystal growth from numerous nucleation sites, where the amorphous solid is produced. In the higher operating temperature region (above 750 °C), it was established that a morphological well-defined and high-dimensional particles of the formed pyrochlore phase can be expected. It was found that at T=850 °C, there is a change in the rate-determining reaction step, from autocatalytic into the contracting volume mechanism.

  12. 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.

  13. HRTEM study of Popigai impact diamond: heterogeneous diamond nanostructures in native amorphous carbon matrix

    Science.gov (United States)

    Kis, Viktoria K.; Shumilova, Tatyana; Masaitis, Victor

    2016-07-01

    High-resolution transmission electron microscopy was applied for the detailed nanostructural investigation of Popigai impact diamonds with the aim of revealing the nature of the amorphous carbon of the matrix. The successful application of two complementary specimen preparation methods, focused ion beam (FIB) milling and mechanical cleavage, allowed direct imaging of nanotwinned nanodiamond crystals embedded in a native amorphous carbon matrix for the first time. Based on its stability under the electron beam, native amorphous carbon can be easily distinguished from the amorphous carbon layer produced by FIB milling during specimen preparation. Electron energy loss spectroscopy of the native amorphous carbon revealed the dominance of sp 2-bonded carbon and the presence of a small amount of oxygen. The heterogeneous size distribution and twin density of the nanodiamond crystals and the structural properties of the native amorphous carbon are presumably related to non-graphitic (organic) carbon precursor material.

  14. Synthetic Astrobiology

    Science.gov (United States)

    Rothschild, Lynn J.

    2016-01-01

    Synthetic biology - the design and construction of new biological parts and systems and the redesign of existing ones for useful purposes - has the potential to transform fields from pharmaceuticals to fuels. Our lab has focused on the potential of synthetic biology to revolutionize all three major parts of astrobiology: Where do we come from? Where are we going? and Are we alone? For the first and third, synthetic biology is allowing us to answer whether the evolutionary narrative that has played out on planet earth is likely to have been unique or universal. For example, in our lab we are re-evolving the biosynthetic pathways of amino acids in order to understand potential capabilities of an early organism with a limited repertoire of amino acids and developing techniques for the recovery of metals from spent electronics on other planetary bodies. And what about the limits for life? Can we create organisms that expand the envelope for life? In the future synthetic biology will play an increasing role in human activities both on earth, in fields as diverse as human health and the industrial production of novel bio-composites. Beyond earth, we will rely increasingly on biologically-provided life support, as we have throughout our evolutionary history. In order to do this, the field will build on two of the great contributions of astrobiology: studies of the origin of life and life in extreme environments.

  15. Synthetic Astrobiology

    Science.gov (United States)

    Rothschild, Lynn J.

    2015-01-01

    Synthetic biology - the design and construction of new biological parts and systems and the redesign of existing ones for useful purposes - has the potential to transform fields from pharmaceuticals to fuels. Our lab has focused on the potential of synthetic biology to revolutionize all three major parts of astrobiology: Where do we come from? Where are we going? and Are we alone? For the first and third, synthetic biology is allowing us to answer whether the evolutionary narrative that has played out on planet earth is likely to have been unique or universal. For example, in our lab we are re-evolving the biosynthetic pathways of amino acids in order to understand potential capabilities of an early organism with a limited repertoire of amino acids and developing techniques for the recovery of metals from spent electronics on other planetary bodies. In the future synthetic biology will play an increasing role in human activities both on earth, in fields as diverse as human health and the industrial production of novel bio-composites. Beyond earth, we will rely increasingly on biologically-provided life support, as we have throughout our evolutionary history. In order to do this, the field will build on two of the great contributions of astrobiology: studies of the origin of life and life in extreme environments.

  16. 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.

  17. Band gap opening in strongly compressed diamond observed by x-ray energy loss spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gamboa, E. J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Fletcher, L. B. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Lee, H. J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); MacDonald, M. J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Univ. of Michigan, Ann Arbor, MI (United States); Zastrau, U. [High-Energy Density Science Group, Hamburg (Germany); Gauthier, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Gericke, D. O. [Univ. of Warwick (United Kingdom); Vorberger, J. [Helmholtz Association of German Research Centres, Dresden (Germany); Granados, E. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Hastings, J. B. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Glenzer, S. H. [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2016-01-25

    The extraordinary mechanical and optical properties of diamond are the basis of numerous technical applications and make diamond anvil cells a premier device to explore the high-pressure behavior of materials. However, at applied pressures above a few hundred GPa, optical probing through the anvils becomes difficult because of the pressure-induced changes of the transmission and the excitation of a strong optical emission. Such features have been interpreted as the onset of a closure of the optical gap in diamond, and can significantly impair spectroscopy of the material inside the cell. In contrast, a comparable widening has been predicted for purely hydrostatic compressions, forming a basis for the presumed pressure stiffening of diamond and resilience to the eventual phase change to BC8. We here present the first experimental evidence of this effect at geo-planetary pressures, exceeding the highest ever reported hydrostatic compression of diamond by more than 200 GPa and any other measurement of the band gap by more than 350 GPa. We here apply laser driven-ablation to create a dynamic, high pressure state in a thin, synthetic diamond foil together with frequency-resolved x-ray scattering as a probe. The frequency shift of the inelastically scattered x-rays encodes the optical properties and, thus, the behavior of the band gap in the sample. Using the ultra-bright x-ray beam from the Linac Coherent Light Source (LCLS), we observe an increasing direct band gap in diamond up to a pressure of 370 GPa. This finding points to the enormous strains in the anvils and the impurities in natural Type Ia diamonds as the source of the observed closure of the optical window. Our results demonstrate that diamond remains an insulating solid to pressures approaching its limit strength.

  18. The first find of a melt inclusion in diamond from the Mir pipe

    Science.gov (United States)

    Bulanova, G. P.; Novgorodov, P. G.; Pavlova, L. A.

    1988-05-01

    Using the sequential-grinding method of Bulanova et al. (1986), designed for the gradual uncovering of diamond inclusions, deep-lying inclusions (including a central partly crystallized melt inclusion, six zonally distributed omphacites, and two pyrope-almandines) were brought to the surface in single-crystal diamond and analyzed using an energy spectrometer. The melt inclusion was found to consist of four phases: the rutile phase, the clinopyroxene phase, the K-Al-Si phase, and the Fe-Ti-Si phase. It is suggested that the melt inclusion is a fragment of a primary melt of rutilic eclogite.

  19. 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

  20. 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 ...

  1. 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.

  2. Elastic and mechanical softening in boron-doped diamond

    Science.gov (United States)

    Liu, Xiaobing; Chang, Yun-Yuan; Tkachev, Sergey N.; Bina, Craig R.; Jacobsen, Steven D.

    2017-01-01

    Alternative approaches to evaluating the hardness and elastic properties of materials exhibiting physical properties comparable to pure diamond have recently become necessary. The classic linear relationship between shear modulus (G) and Vickers hardness (HV), along with more recent non-linear formulations based on Pugh’s modulus extending into the superhard region (HV > 40 GPa) have guided synthesis and identification of novel superabrasives. These schemes rely on accurately quantifying HV of diamond-like materials approaching or potentially exceeding the hardness of the diamond indenter, leading to debate about methodology and the very definition of hardness. Elasticity measurements on such materials are equally challenging. Here we used a high-precision, GHz-ultrasonic interferometer in conjunction with a newly developed optical contact micrometer and 3D optical microscopy of indentations to evaluate elasticity-hardness relations in the ultrahard range (HV > 80 GPa) by examining single-crystal boron-doped diamond (BDD) with boron contents ranging from 50–3000 ppm. We observe a drastic elastic-mechanical softening in highly doped BDD relative to the trends observed for superhard materials, providing insight into elasticity-hardness relations for ultrahard materials. PMID:28233808

  3. Elastic and mechanical softening in boron-doped diamond.

    Science.gov (United States)

    Liu, Xiaobing; Chang, Yun-Yuan; Tkachev, Sergey N; Bina, Craig R; Jacobsen, Steven D

    2017-02-24

    Alternative approaches to evaluating the hardness and elastic properties of materials exhibiting physical properties comparable to pure diamond have recently become necessary. The classic linear relationship between shear modulus (G) and Vickers hardness (HV), along with more recent non-linear formulations based on Pugh's modulus extending into the superhard region (HV > 40 GPa) have guided synthesis and identification of novel superabrasives. These schemes rely on accurately quantifying HV of diamond-like materials approaching or potentially exceeding the hardness of the diamond indenter, leading to debate about methodology and the very definition of hardness. Elasticity measurements on such materials are equally challenging. Here we used a high-precision, GHz-ultrasonic interferometer in conjunction with a newly developed optical contact micrometer and 3D optical microscopy of indentations to evaluate elasticity-hardness relations in the ultrahard range (HV > 80 GPa) by examining single-crystal boron-doped diamond (BDD) with boron contents ranging from 50-3000 ppm. We observe a drastic elastic-mechanical softening in highly doped BDD relative to the trends observed for superhard materials, providing insight into elasticity-hardness relations for ultrahard materials.

  4. Large piezoresistive effect in surface conductive nanocrystalline diamond

    Energy Technology Data Exchange (ETDEWEB)

    Janssens, S. D., E-mail: stoffel.d.janssens@gmail.com; Haenen, K., E-mail: ken.haenen@uhasselt.be [Institute for Materials Research (IMO), Hasselt University, Wetenschapspark 1, B-3590 Diepenbeek (Belgium); IMOMEC, IMEC vzw, Wetenschapspark 1, B-3590 Diepenbeek (Belgium); Drijkoningen, S. [Institute for Materials Research (IMO), Hasselt University, Wetenschapspark 1, B-3590 Diepenbeek (Belgium)

    2014-09-08

    Surface conductivity in hydrogen-terminated single crystal diamond is an intriguing phenomenon for fundamental reasons as well as for application driven research. Surface conductivity is also observed in hydrogen-terminated nanocrystalline diamond although the electronic transport mechanisms remain unclear. In this work, the piezoresistive properties of intrinsic surface conductive nanocrystalline diamond are investigated. A gauge factor of 35 is calculated from bulging a diamond membrane of 350 nm thick, with a diameter of 656 μm and a sheet resistance of 1.45 MΩ/sq. The large piezoresistive effect is reasoned to originate directly from strain-induced changes in the resistivity of the grain boundaries. Additionally, we ascribe a small time-dependent fraction of the piezoresistive effect to charge trapping of charge carriers at grain boundaries. In conclusion, time-dependent piezoresistive effect measurements act as a tool for deeper understanding the complex electronic transport mechanisms induced by grain boundaries in a polycrystalline material or nanocomposite.

  5. Nanostructured diamond-TiC composites with high fracture toughness

    Science.gov (United States)

    Wang, Haikuo; He, Duanwei; Xu, Chao; Tang, Mingjun; Li, Yu; Dong, Haini; Meng, Chuanmin; Wang, Zhigang; Zhu, Wenjun

    2013-01-01

    We report the preparation of nanostructured diamond-TiC composites with high fracture toughness and high hardness starting from a ball-milled mixture of nano-sized Ti3SiC2 and submicron-sized diamond by simultaneously tuning the pressure-temperature conditions. The phase segregation of Ti3SiC2 at pressure of 5.5 GPa were investigated by X-ray diffraction and high resolution transmission electron microscopy, we found that the Ti3SiC2 could decompose into nanosized TiC and amorphous Ti-Si at 600-700 °C. The subsequent reaction between diamond and Ti-Si led to an amorphous Ti-Si-C matrix in which diamond and TiC crystals are embedded. With a loading force of 98 N, the measured fracture toughness KIC and Vicker's hardness HV of the synthesized composites reach up to 14 MPa m1/2 and 45.5 GPa, respectively. Our results demonstrate that the nanocrystalline/amorphous bonding matrix could largely enhance the toughness of the brittle composites.

  6. Elastic and mechanical softening in boron-doped diamond

    Science.gov (United States)

    Liu, Xiaobing; Chang, Yun-Yuan; Tkachev, Sergey N.; Bina, Craig R.; Jacobsen, Steven D.

    2017-02-01

    Alternative approaches to evaluating the hardness and elastic properties of materials exhibiting physical properties comparable to pure diamond have recently become necessary. The classic linear relationship between shear modulus (G) and Vickers hardness (HV), along with more recent non-linear formulations based on Pugh’s modulus extending into the superhard region (HV > 40 GPa) have guided synthesis and identification of novel superabrasives. These schemes rely on accurately quantifying HV of diamond-like materials approaching or potentially exceeding the hardness of the diamond indenter, leading to debate about methodology and the very definition of hardness. Elasticity measurements on such materials are equally challenging. Here we used a high-precision, GHz-ultrasonic interferometer in conjunction with a newly developed optical contact micrometer and 3D optical microscopy of indentations to evaluate elasticity-hardness relations in the ultrahard range (HV > 80 GPa) by examining single-crystal boron-doped diamond (BDD) with boron contents ranging from 50–3000 ppm. We observe a drastic elastic-mechanical softening in highly doped BDD relative to the trends observed for superhard materials, providing insight into elasticity-hardness relations for ultrahard materials.

  7. Biological evaluation of ultrananocrystalline and nanocrystalline diamond coatings.

    Science.gov (United States)

    Skoog, Shelby A; Kumar, Girish; Zheng, Jiwen; Sumant, Anirudha V; Goering, Peter L; Narayan, Roger J

    2016-12-01

    Nanostructured biomaterials have been investigated for achieving desirable tissue-material interactions in medical implants. Ultrananocrystalline diamond (UNCD) and nanocrystalline diamond (NCD) coatings are the two most studied classes of synthetic diamond coatings; these materials are grown using chemical vapor deposition and are classified based on their nanostructure, grain size, and sp(3) content. UNCD and NCD are mechanically robust, chemically inert, biocompatible, and wear resistant, making them ideal implant coatings. UNCD and NCD have been recently investigated for ophthalmic, cardiovascular, dental, and orthopaedic device applications. The aim of this study was (a) to evaluate the in vitro biocompatibility of UNCD and NCD coatings and (b) to determine if variations in surface topography and sp(3) content affect cellular response. Diamond coatings with various nanoscale topographies (grain sizes 5-400 nm) were deposited on silicon substrates using microwave plasma chemical vapor deposition. Scanning electron microscopy and atomic force microscopy revealed uniform coatings with different scales of surface topography; Raman spectroscopy confirmed the presence of carbon bonding typical of diamond coatings. Cell viability, proliferation, and morphology responses of human bone marrow-derived mesenchymal stem cells (hBMSCs) to UNCD and NCD surfaces were evaluated. The hBMSCs on UNCD and NCD coatings exhibited similar cell viability, proliferation, and morphology as those on the control material, tissue culture polystyrene. No significant differences in cellular response were observed on UNCD and NCD coatings with different nanoscale topographies. Our data shows that both UNCD and NCD coatings demonstrate in vitro biocompatibility irrespective of surface topography.

  8. 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

  9. 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.

  10. The crystal structure of Z-Aib-Gly-Aib-Leu-Aib-OtBu, the synthetic, protected N-terminal pentapeptide of trichotoxin.

    Science.gov (United States)

    Gessmann, R; Brueckner, H; Kokkinidis, M

    1991-01-01

    Z-Aib-Gly-Aib-Leu-Aib-OtBu, the alpha-aminoisobutyric acid (Aib)-containing N-terminal pentapeptide of the antibiotic trichotoxin, has been studied by x-ray crystallography. The molecule forms a right-handed helix with a reversal of the sense of the helix at the C-terminus. Torsion angles and hydrogen bonding pattern are consistent with a mixed 3(10)-/alpha-helical conformation. In the crystal, continuous columns are formed by head-to-tail arrangement of hydrogen-bonded molecules along the helix axis. The helical columns associate via hydrogen bonds forming closely packed parallel pairs.

  11. Hybrid nanocavities for resonant enhancement of color center emission in diamond

    CERN Document Server

    Barclay, Paul E; Santori, Charles; Faraon, Andrei; Beausoleil, Raymond G

    2011-01-01

    Resonantly enhanced emission from the zero phonon line of a diamond nitrogen-vacancy (NV) center in single crystal diamond is demonstrated experimentally using a hybrid whispering gallery mode nanocavity. A 900 nm diameter ring nanocavity formed from gallium phosphide, whose sidewalls extend into a diamond substrate, is tuned onto resonance at low-temperature with the zero phonon line of a negatively charged NV center implanted near the diamond surface. When the nanocavity is on resonance, the zero phonon line intensity is enhanced by approximately an order of magnitude, and the spontaneous emission lifetime of the NV is reduced as much as 18%, corresponding to a 6.3X enhancement of emission in the zero photon line.

  12. The chemo-mechanical effect of cutting fluid on material removal in diamond scribing of silicon

    Science.gov (United States)

    Kumar, Arkadeep; Melkote, Shreyes N.

    2017-07-01

    The mechanical integrity of silicon wafers cut by diamond wire sawing depends on the damage (e.g., micro-cracks) caused by the cutting process. The damage type and extent depends on the material removal mode, i.e., ductile or brittle. This paper investigates the effect of cutting fluid on the mode of material removal in diamond scribing of single crystal silicon, which simulates the material removal process in diamond wire sawing of silicon wafers. We conducted scribing experiments with a diamond tipped indenter in the absence (dry) and in the presence of a water-based cutting fluid. We found that the cutting mode is more ductile when scribing in the presence of cutting fluid compared to dry scribing. We explain the experimental observations by the chemo-mechanical effect of the cutting fluid on silicon, which lowers its hardness and promotes ductile mode material removal.

  13. Influence of brazing parameters and alloy composition on interface morphology of brazed diamond

    Energy Technology Data Exchange (ETDEWEB)

    Klotz, Ulrich E. [Empa, Swiss Federal Laboratories for Materials Testing and Research, Laboratory for Joining and Interface Technology, Uberlandstrasse 129, CH-8600 Duebendorf (Switzerland)], E-mail: klotz@fem-online.de; Liu Chunlei [Empa, Swiss Federal Laboratories for Materials Testing and Research, Laboratory for Joining and Interface Technology, Uberlandstrasse 129, CH-8600 Duebendorf (Switzerland); Khalid, Fazal A. [Faculty of Metallurgy and Materials Engineering, GIK Institute, Topi, NWFP (Pakistan); Elsener, Hans-Rudolf [Empa, Swiss Federal Laboratories for Materials Testing and Research, Laboratory for Joining and Interface Technology, Uberlandstrasse 129, CH-8600 Duebendorf (Switzerland)

    2008-11-15

    Active brazing is an effective technique for joining diamond or cBN grit to metallic substrates. This technique is currently used to manufacture superabrasive, high-performance tools. The investigation of interface reactions between diamond and active brazing alloys plays an important role in understanding and improving the brazing process and the resultant tool performance. Focused ion beam (FIB) milling enabled the high resolution investigation of these extremely difficult to prepare metal-diamond joints. The interfacial nanostructure is characterized by the formation of two layers of TiC with different morphologies. First a cuboidal layer forms directly on the diamond and reaches a thickness of approximately 70 nm. Then a second layer with columnar TiC crystals grows on the first layer into the brazing filler metal by a diffusion-controlled process. The combined thickness of both TiC layers varies between 50 nm and 600 nm depending on the brazing temperature and holding time.

  14. 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.

  15. Synthetic chromosomes.

    Science.gov (United States)

    Schindler, Daniel; Waldminghaus, Torsten

    2015-11-01

    What a living organism looks like and how it works and what are its components-all this is encoded on DNA, the genetic blueprint. Consequently, the way to change an organism is to change its genetic information. Since the first pieces of recombinant DNA have been used to transform cells in the 1970s, this approach has been enormously extended. Bigger and bigger parts of the genetic information have been exchanged or added over the years. Now we are at a point where the construction of entire chromosomes becomes a reachable goal and first examples appear. This development leads to fundamental new questions, for example, about what is possible and desirable to build or what construction rules one needs to follow when building synthetic chromosomes. Here we review the recent progress in the field, discuss current challenges and speculate on the appearance of future synthetic chromosomes.

  16. 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.

  17. 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.

  18. Tracking Crust-Mantle Recycling through Superdeep Diamonds and their Mineral Inclusions

    Science.gov (United States)

    Walter, Michael; Bulanova, Galina; Smith, Chris; Thomson, Andrew; Kohn, Simon; Burnham, Antony

    2013-04-01

    Sublithospheric, or 'superdeep' diamonds, originate in the deep upper mantle, transition zone, and at least as deep as the shallow lower mantle. When diamonds crystallize in the mantle from fluids or melts they occasionally entrap coexisting mineral phases. Because of their great physical resiliency, diamonds can potentially preserve information over long distance- and time-scales, revealing important information about the petrologic, tectonic and geodynamic environment in which the diamonds grew and were transported. Superdeep diamonds and their inclusions have proven especially powerful for probing processes related to subduction of slabs into the deep mantle [1-3]. In contrast to lithospheric diamonds that are effectively frozen-in geodynamically, mineral inclusions in superdeep diamonds often record hundreds of kilometers of uplift in the convecting mantle from their original depth of origin [3-5]. The phase equilibria of unmixing of original deep mantle phases such as Ca- and Mg-perovskite, NAL-phase, CF-phase, CAS-phase, and majorite provide a means to establish amounts of uplift. The few available age constraints indicate superdeep diamond growth from the Proterozoic to the Cretaceous, and further dating can potentially lead to constraining mantle upwelling rates [4]. Here we will provide several examples showing how superdeep diamonds and their inclusions record processes of subduction and slab foundering, and ultimately recycling of slab material from the transition zone and lower mantle into the shallow upper mantle. 1. Harte, B., Mineralogical Magazine, 2010. 74: p. 189-215. 2. Tappert, R., et al., Geology, 2005. 33: p. 565-568. 3. Walter, M.J., et al., Science, 2011. 333: p. 54-57. 4. Bulanova, G.P., et al., Contributions to Mineralogy and Petrology, 2010. 160: p. 489-510. 5. Harte, B. and N. Cayzer, Physics and Chemistry of Minerals, 2007.

  19. Microscopic properties of MPCVD diamond coatings studied by micro-Raman and micro-photoluminescence spectroscopy

    Indian Academy of Sciences (India)

    Kalyan S Pal; Awadesh K Mallik; Nandadulal Dandapat; Nihar R Ray; Someswar Datta; Sandip Bysakh; Bichitra K Guha

    2015-04-01

    Diamond coatings were deposited on silicon (100) substrate using the microwave plasma chemical vapour deposition (MPCVD) technique at different process conditions. Process parameters such as CH4–H2 gas mixture concentration, microwave power, chamber pressure and substrate temperature were varied. The diamond coatings were characterized by micro-Raman and micro-photoluminescence (PL) spectroscopy techniques. In this paper we report a comparison of the overall quality of MPCVD polycrystalline diamond coatings grown under different processing conditions in terms of stress distribution, thickness uniformity and surface roughness. Micro-Raman spectroscopy studies over various points on the deposited coating showed that the Raman line widths of diamond peak varied from 3.2 to 18.3 cm−1 with the variation of CH4 and H2 gas concentration. The micro-PL spectra suggested the presence of impurity concentration and defects within the diamond coating synthesized at different processing conditions. Transmission electron microscopy (TEM) images provide the direct evidence of the presence of crystal defects which corroborates the Raman and PL results. The coherence scanning interferometry (CSI) showed that surface roughness of diamond coating varied from 0.43 to 11 m with thickness at different positions of the three coating samples. It has been concluded that Raman line-width broadening and Raman-shift are due to the presence of crystal defects as well as non-uniform distribution of stresses present in the diamond crystals of the coating, due to the incorporation of Si as impurity element and non-uniform temperature distribution during growth. Defect density gets reduced at higher processing temperatures. It is also being proposed that better thickness uniformity and lower surface roughness can be achieved for coatings deposited at low methane concentration under optimized process conditions.

  20. 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...