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Sample records for si beam developments

  1. Development of the fabrication process of SiC composite by radiation beam

    International Nuclear Information System (INIS)

    Park, Ji Yeon; Kim, Weon Ju; Jung, Choong Hwan; Woo, Chang Hyeon; Ryu, Woo Seog

    2006-01-01

    In order to operate the nuclear system at high temperatures, core materials with a good irradiation resistance at high temperatures must be developed. SiC composite is one of candidates for high temperature structural materials. Among several fabrication processes, the PIP process includes the curing and pyrolysis process. Generally, the thermal oxidation curing method has some disadvantages; difficulty in the control of oxygen contents and volatilization of many constituents. To overcome these disadvantages and reduce the process time, a new and improved method like the beam curing process has been proposed as one of the effective methods for the fabrication of SiC composite. In this study, the electron beam curing method in the PIP process was optimized to develop SiCf/SiC composite with low oxygen contents. Using the electron beam curing method with full doses of 2∼10 MGy and the pyrolysis process at 1300∼1400 .deg. C, composite with the oxygen content of less than 1 wt% could be obtained. Additionally, if the slurry impregnation and curing/pyrolysis processes were repeated several times, dense composite could be produced

  2. $^{31}$Si Self-Diffusion in Si-Ge Alloys and Si-(B-)C-N Ceramics and Diffusion Studies for Al and Si Beam Developments

    CERN Multimedia

    Nylandsted larsen, A; Voss, T L; Strohm, A

    2002-01-01

    An invaluable method for studying diffusion in solids is the radiotracer technique. However, its applicability had been restricted to radiotracer atoms with half-lives $t_{1/2}$ of about 1~d or longer. Within the framework of IS372 a facility was developed in which short-lived radiotracer atoms ( 5min $\\scriptstyle{\\lesssim}$ $t_{1/2}\\scriptstyle{\\lesssim}$1 d ) can be used. For the implantation of the short-lived tracers the facility is flanged to the ISOLDE beamline, and all post-implantation steps required in the radiotracer technique are done in situ.\\\\ After successful application of this novel technique in diffusion studies of $^{11}$C ($t_{1/2}$ = 20.3 min), this experiment aims at performing self-diffusion studies of $^{31}$Si ($t_{1/2}$ = 2.6~h) in Si--Ge alloys and in amorphous Si--(B--)C--N ceramics.\\\\ Our motivation for measuring diffusion in Si--Ge alloys is their recent technological renaissance as well as the purpose to test the prediction that in these alloys the self-diffusion mechanism chang...

  3. Ion beam processes in Si

    International Nuclear Information System (INIS)

    Holland, O.W.; Narayan, J.; Fathy, D.

    1984-07-01

    Observation of the effects of implants of energetic ions at high dose rates into Si have produced some exciting and interesting results. The mechanism whereby displacement damage produced by ions self-anneals during high dose rate implantation is discussed. It is shown that ion beam annealing (IBA) offers in certain situations unique possibilities for damage annealing. Annealing results of the near surface in Si with a buried oxide layer, formed by high dose implantation, are presented in order to illustrate the advantages offered by IBA. It is also shown that ion irradiation can stimulate the epitaxial recrystallization of amorphous overlayers in Si. The nonequilibrium alloying which results from such epitaxial processes is discussed as well as mechanisms which limit the solid solubility during irradiation. Finally, a dose rate dependency for the production of stable damage by ion irradiation at a constant fluence has been observed. For low fluence implants, the amount of damage is substantially greater in the case of high flux rather than low flux implantation

  4. RBS using {sup 28}Si beams

    Energy Technology Data Exchange (ETDEWEB)

    Ophel, T.R. [Australian National Univ., Canberra, ACT (Australia); Mitchell, I.V. [University of Western Ontario, London, ON (Canada). Dept. of Physics

    1996-12-31

    Measurements of RBS using {sup 28}Si beams have been made to evaluate the enhancement of sensitivity that should obtain from kinematic suppression of silicon substrate scattering. Two detection methods were tried. Aside from a surface barrier detector, a magnetic spectrometer, instrumented with a multi-electrode gas focal plane detector, was used to indicate the resolution attainable with low energy {sup 28}Si ions. The results confirm that kinematically suppressed RBS does provide greatly improved sensitivity. 5 refs., 2 figs.

  5. RBS using {sup 28}Si beams

    Energy Technology Data Exchange (ETDEWEB)

    Ophel, T R [Australian National Univ., Canberra, ACT (Australia); Mitchell, I V [University of Western Ontario, London, ON (Canada). Dept. of Physics

    1997-12-31

    Measurements of RBS using {sup 28}Si beams have been made to evaluate the enhancement of sensitivity that should obtain from kinematic suppression of silicon substrate scattering. Two detection methods were tried. Aside from a surface barrier detector, a magnetic spectrometer, instrumented with a multi-electrode gas focal plane detector, was used to indicate the resolution attainable with low energy {sup 28}Si ions. The results confirm that kinematically suppressed RBS does provide greatly improved sensitivity. 5 refs., 2 figs.

  6. Positron annihilation in SiO 2-Si studied by a pulsed slow positron beam

    Science.gov (United States)

    Suzuki, R.; Ohdaira, T.; Uedono, A.; Kobayashi, Y.

    2002-06-01

    Positron and positronium (Ps) behavior in SiO 2-Si have been studied by means of positron annihilation lifetime spectroscopy (PALS) and age-momentum correlation (AMOC) spectroscopy with a pulsed slow positron beam. The PALS study of SiO 2-Si samples, which were prepared by a dry-oxygen thermal process, revealed that the positrons implanted in the Si substrate and diffused back to the interface do not contribute to the ortho-Ps long-lived component, and the lifetime spectrum of the interface has at least two components. From the AMOC study, the momentum distribution of the ortho-Ps pick-off annihilation in SiO 2, which shows broader momentum distribution than that of crystalline Si, was found to be almost the same as that of free positron annihilation in SiO 2. A varied interface model was proposed to interpret the results of the metal-oxide-semiconductor (MOS) experiments. The narrow momentum distribution found in the n-type MOS with a negative gate bias voltage could be attributed to Ps formation and rapid spin exchange in the SiO 2-Si interface. We have developed a two-dimensional positron lifetime technique, which measures annihilation time and pulse height of the scintillation gamma-ray detector for each event. Using this technique, the positronium behavior in a porous SiO 2 film, grown by a sputtering method, has been studied.

  7. Gas-source molecular beam epitaxy of Si(111) on Si(110) substrates by insertion of 3C-SiC(111) interlayer for hybrid orientation technology

    Energy Technology Data Exchange (ETDEWEB)

    Bantaculo, Rolando, E-mail: rolandobantaculo@yahoo.com; Saitoh, Eiji; Miyamoto, Yu; Handa, Hiroyuki; Suemitsu, Maki

    2011-11-01

    A method to realize a novel hybrid orientations of Si surfaces, Si(111) on Si(110), has been developed by use of a Si(111)/3C-SiC(111)/Si(110) trilayer structure. This technology allows us to use the Si(111) portion for the n-type and the Si(110) portion for the p-type channels, providing a solution to the current drive imbalance between the two channels confronted in Si(100)-based complementary metal oxide semiconductor (CMOS) technology. The central idea is to use a rotated heteroepitaxy of 3C-SiC(111) on Si(110) substrate, which occurs when a 3C-SiC film is grown under certain growth conditions. Monomethylsilane (SiH{sub 3}-CH{sub 3}) gas-source molecular beam epitaxy (GSMBE) is used for this 3C-SiC interlayer formation while disilane (Si{sub 2}H{sub 6}) is used for the top Si(111) layer formation. Though the film quality of the Si epilayer leaves a lot of room for betterment, the present results may suffice to prove its potential as a new technology to be used in the next generation CMOS devices.

  8. Development of neutral beam source using electron beam excited plasma

    International Nuclear Information System (INIS)

    Hara, Yasuhiro; Hamagaki, Manabu; Mise, Takaya; Hara, Tamio

    2011-01-01

    A low-energy neutral beam (NB) source, which consists of an electron-beam-excited plasma (EBEP) source and two carbon electrodes, has been developed for damageless etching of ultra-large-scale integrated (ULSI) devices. It has been confirmed that the Ar ion beam energy was controlled by the acceleration voltage and the beam profile had good uniformity over the diameter of 80 mm. Dry etching of a Si wafer at the floating potential has been carried out by Ar NB. Si sputtering yield by an Ar NB clearly depends on the acceleration voltage. This result shows that the NB has been generated through the charge exchange reaction from the ion beam in the process chamber. (author)

  9. Si etching with reactive neutral beams of very low energy

    Energy Technology Data Exchange (ETDEWEB)

    Hara, Yasuhiro [Organization for Research and Development of Innovative Science and Technology, Kansai University, 3-3-35 Yamate-chou, Suita, Osaka 565-0871 (Japan); Hamagaki, Manabu; Mise, Takaya [RIKEN, 2-1, Hirosawa, Wako, Saitama 351-0198 (Japan); Iwata, Naotaka; Hara, Tamio [Toyota Technological Institute, 2-12-1 Hisakata, Tenpaku-ku, Nagoya 468-8511 (Japan)

    2014-12-14

    A Si etching process has been investigated with reactive neutral beams (NBs) extracted using a low acceleration voltage of less than 100 V from CF{sub 4} and Ar mixed plasmas. The etched Si profile shows that the etching process is predominantly anisotropic. The reactive NB has a constant Si etching rate in the acceleration voltage range from 20 V to 80 V. It is considered that low-energy NBs can trigger Si etching because F radicals adsorb onto the Si surface and weaken Si–Si bonds. The etching rate per unit beam flux is 33 times higher than that with Ar NB. These results show that the low-energy reactive NB is useful for damage-free high speed Si etching.

  10. Particle beam source development

    International Nuclear Information System (INIS)

    Anon.

    1978-01-01

    Electron beam research directed toward providing improved in-diode pinched beam sources and establishing the efficiency and feasibility for superposition of many beams progressed in three major areas. Focusing stability has been improved from large effective aspect ratio (radius/gap of emitting surface) diodes. Substantial progress toward establishing the feasibility of combining beams guided along ionized current-carrying channels has been made. Two beams have been transported and overlayed on a target. Theoretical and experimental measurements on channel formation have resulted in specifications for the capacitor bank channel initiation system for a 12-beam combination experiment on Proto II. An additional area of beam research has been the development of a small pulsed X-ray source to yield high quality flash X-radiography of pellets. A source yielding approximately 100-μm resolution of objects has been demonstrated and work continues to improve the convenience and reliability of this source. The effort to extend the capability of higher power conventional pulse power generators to accelerate ions (rather than electrons), and assess the feasibility of this technology variation for target experiments and reactors has progressed. Progress toward development of a multistage accelerator for ions with pulse power technology centered on development of a new laboratory facility and design and procurement of hardware for a five-stage test apparatus for the Pulslac concept

  11. Underling modification in ion beam induced Si wafers

    International Nuclear Information System (INIS)

    Hazra, S.; Chini, T.K.; Sanyal, M.K.; Grenzer, J.; Pietsch, U.

    2005-01-01

    Subsurface (amorphous-crystalline interface) structure of keV ion beam modified Si(001) wafers was studied for the first time using non-destructive technique and compared with that of the top one. Ion-beam modifications of the Si samples were done using state-of-art high-current ion implanter facility at Saha Institute of Nuclear Physics by changing energy, dose and angle of incidence of the Ar + ion beam. To bring out the underlying modification depth-resolved x-ray grazing incidence diffraction has been carried out using synchrotron radiation facility, while the structure of the top surface was studied through atomic force microscopy

  12. Neutral beam development plan

    International Nuclear Information System (INIS)

    Staten, H.S.

    1980-08-01

    The national plan is presented for developing advanced injection systems for use on upgrades of existing experiments, and use on future facilities such as ETF, to be built in the late 1980's or early 90's where power production from magnetic fusion will move closer to a reality. Not only must higher power and longer pulse length systems be developed , but they must operate reliably; they must be a tool for the experimenter, not the experiment itself. Neutral beam systems handle large amounts of energy and as such, they often are as complicated as the plasma physics experiment itself. This presents a significant challenge to the neutral beam developer

  13. Germanium growth on electron beam lithography patterned Si3N4/Si(001) substrate using molecular beam epitaxy

    Science.gov (United States)

    Sarkar, Subhendu Sinha; Katiyar, Ajit K.; Sarkar, Arijit; Dhar, Achintya; Rudra, Arun; Khatri, Ravinder K.; Ray, Samit Kumar

    2018-04-01

    It is important to investigate the growth dynamics of Ge adatoms under different surface stress regimes of the patterned dielectric to control the selective growth of self-assembled Ge nanostructures on silicon. In the present work, we have studied the growth of Ge by molecular beam epitaxy on nanometer scale patterned Si3N4/Si(001) substrates generated using electron beam lithography. The pitch of the patterns has been varied to investigate its effect on the growth of Ge in comparison to un-patterned Si3N4. For the patterned Si3N4 film, Ge did not desorbed completely from the Si3N4 film and hence no site selective growth pattern is observed. Instead, depending upon the pitch, Ge growth has occurred in different growth modes around the openings in the Si3N4. For the un-patterned substrate, the morphology exhibits the occurrence of uniform 3D clustering of Ge adatoms on Si3N4 film. This variation in the growth modes of Ge is attributed to the variation of residual stress in the Si3N4 film for different pitch of holes, which has been confirmed theoretically through Comsol Multiphysics simulation. The variation in stress for different pitches resulted in modulation of surface energy of the Si3N4 film leading to the different growth modes of Ge.

  14. Microstructure of SiC ceramics fabricated by pyrolysis of electron beam irradiated polycarbomethylsilane containing precursors

    International Nuclear Information System (INIS)

    Xu Yunshu; Tanaka, Shigeru

    2003-01-01

    A modified gel-casting method was developed to form the ceramics precursor matrix by using polycarbomehylsilane (PCMS) and SiC powder. The polymer precursor was mixed with SiC powder in toluene, and then the slurry samples were cast into designed shapes. The pre-ceramic samples were then irradiated by 2.0 MeV electron beam generated by a Cockcroft-Walton type accelerator in He gas flow to about 15 MGy. The cured samples were pyrolyzed and sintered into SiC ceramics at 1300degC in Ar gas. The modified gel-casting method leaves almost no internal stress in the pre-ceramic samples, and the electron beam curing not only diminished the amount of pyrolysis gaseous products but also enhanced the interface binding of the polymer converted SiC and the grains of SiC powder. Optical microscope, AFM and SEM detected no visible internal or surface cracks in the final SiC ceramics matrix. A maximum value of 122 MPa of flexural strength of the final SiC ceramics was achieved. (author)

  15. Irradiation effects of Ar cluster ion beams on Si substrates

    International Nuclear Information System (INIS)

    Ishii, Masahiro; Sugahara, Gaku; Takaoka, G.H.; Yamada, Isao

    1993-01-01

    Gas-cluster ion beams can be applied to new surface modification techniques such as surface cleaning, low damage sputtering and shallow junction formation. The effects of energetic Ar cluster impacts on solid surface were studied for cluster energies of 10-30keV. Irradiation effects were studied by RBS. For Si(111) substrates, irradiated with Ar ≥500 clusters to a dose of 1x10 15 ion/cm 2 at acceleration voltage 15kV, 2x10 14 atoms/cm 2 implanted Ar atoms were detected. In this case, the energy per cluster atom was smaller than 30eV; at this energy, no significant implantation occurs in the case of monomer ions. Ar cluster implantation into Si substrates occurred due to the high energy density irradiation. (author)

  16. Ion beam mixing of marker layers in Al and Si

    International Nuclear Information System (INIS)

    Mantl, S.; Rehn, L.E.; Averback, R.S.; Thompson, L.J. Jr.

    1984-07-01

    Ion beam mixing experiments on thin Pt, Au, and Ni markers in Al and Si have performed at 17, 85, and 300 K. After irradiation with 300-keV Ar ions the broadening and relative shifts of the markers have been determined by RBS measurements. The marker broadenings are more pronounced in Si than in Al; in both matrices the broadenings decrease in the following order: Au, Pt, and Ni. No dependence of mixing on irradiation temperature was observed between 17 and 300 K. The shifts of the heavy Au and Pt markers relative to the Ni markers are approximately equal to the experimental accuracy. However, a shift of the Ni marker toward the surface relative to the heavier Au and Pt markers was consistently observed. 13 references, 2 figures

  17. High performance Si immersion gratings patterned with electron beam lithography

    Science.gov (United States)

    Gully-Santiago, Michael A.; Jaffe, Daniel T.; Brooks, Cynthia B.; Wilson, Daniel W.; Muller, Richard E.

    2014-07-01

    Infrared spectrographs employing silicon immersion gratings can be significantly more compact than spectro- graphs using front-surface gratings. The Si gratings can also offer continuous wavelength coverage at high spectral resolution. The grooves in Si gratings are made with semiconductor lithography techniques, to date almost entirely using contact mask photolithography. Planned near-infrared astronomical spectrographs require either finer groove pitches or higher positional accuracy than standard UV contact mask photolithography can reach. A collaboration between the University of Texas at Austin Silicon Diffractive Optics Group and the Jet Propulsion Laboratory Microdevices Laboratory has experimented with direct writing silicon immersion grating grooves with electron beam lithography. The patterning process involves depositing positive e-beam resist on 1 to 30 mm thick, 100 mm diameter monolithic crystalline silicon substrates. We then use the facility JEOL 9300FS e-beam writer at JPL to produce the linear pattern that defines the gratings. There are three key challenges to produce high-performance e-beam written silicon immersion gratings. (1) E- beam field and subfield stitching boundaries cause periodic cross-hatch structures along the grating grooves. The structures manifest themselves as spectral and spatial dimension ghosts in the diffraction limited point spread function (PSF) of the diffraction grating. In this paper, we show that the effects of e-beam field boundaries must be mitigated. We have significantly reduced ghost power with only minor increases in write time by using four or more field sizes of less than 500 μm. (2) The finite e-beam stage drift and run-out error cause large-scale structure in the wavefront error. We deal with this problem by applying a mark detection loop to check for and correct out minuscule stage drifts. We measure the level and direction of stage drift and show that mark detection reduces peak-to-valley wavefront error

  18. Degradation effects ad Si-depth profiling in photoresists using ion beam analysis

    International Nuclear Information System (INIS)

    Ijzendoorn, L.J. van; Schellekens, J.P.W.

    1989-01-01

    The reaction of silicon-containing vapour with a photoresist layer, as used in dry developable lithographic processes, was studied with Rutherford backscattering spectrometry (RBS). Degradation of the polymer layer was observed, but the total amount of incorporated Si was found to be constant during the measurement. Si-depth profiles were found to be independent of dose and in agreement with profiles obtained with secondary ion mass spectrometry (SIMS). The detection of hydrogen by elastic recoil detection (ERD) was used to study the degradation in detail. The decrease in hydrogen countrate from a layer of polystyrene on Si in combination with the shift of the Si-substrate edge in the corresponding RBS spectra was used for a model description. Only one degradation cross-section for hydrogen and one for carbon, both independent of beam current and dose, were required for a successful fit of the experimental data. (orig.)

  19. Molecular beam epitaxy grown Ge/Si pin layer sequence for photonic devices

    International Nuclear Information System (INIS)

    Schulze, J.; Oehme, M.; Werner, J.

    2012-01-01

    A key challenge to obtain a convergence of classical Si-based microelectronics and optoelectronics is the manufacturing of photonic integrated circuits integrable into classical Si-based integrated circuits. This integration would be greatly enhanced if similar facilities and technologies could be used. Therefore one approach is the development of optoelectronic components and devices made from group-IV-based materials such as SiGe, Ge or Ge:Sn. In this paper the optoelectronic performances of a pin diode made from a Ge/Si heterostructure pin layer sequence grown by molecular beam epitaxy are discussed. After a detailed description of the layer sequence growth and the device manufacturing process it will be shown that – depending on the chosen operating point and device design – the diode serves as a broadband high speed photo detector, Franz–Keldysh effect modulator or light emitting diode.

  20. Molecular beam epitaxy grown Ge/Si pin layer sequence for photonic devices

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, J., E-mail: schulze@iht.uni-stuttgart.de; Oehme, M.; Werner, J.

    2012-02-01

    A key challenge to obtain a convergence of classical Si-based microelectronics and optoelectronics is the manufacturing of photonic integrated circuits integrable into classical Si-based integrated circuits. This integration would be greatly enhanced if similar facilities and technologies could be used. Therefore one approach is the development of optoelectronic components and devices made from group-IV-based materials such as SiGe, Ge or Ge:Sn. In this paper the optoelectronic performances of a pin diode made from a Ge/Si heterostructure pin layer sequence grown by molecular beam epitaxy are discussed. After a detailed description of the layer sequence growth and the device manufacturing process it will be shown that - depending on the chosen operating point and device design - the diode serves as a broadband high speed photo detector, Franz-Keldysh effect modulator or light emitting diode.

  1. Onset temperature for Si nanostructure growth on Si substrate during high vacuum electron beam annealing.

    Science.gov (United States)

    Fang, F; Markwitz, A

    2009-05-01

    Silicon nanostructures, called Si nanowhiskers, are successfully synthesized on Si(100) substrate by high vacuum electron beam annealing. The onset temperature and duration needed for the Si nanowhiskers to grow was investigated. It was found that the onset and growth morphology of Si nanowhiskers strongly depend on the annealing temperature and duration applied in the annealing cycle. The onset temperature for nanowhisker growth was determined as 680 degrees C using an annealing duration of 90 min and temperature ramps of +5 degrees C s(-1) for heating and -100 degrees C s(-1) for cooling. Decreasing the annealing time at peak temperature to 5 min required an increase in peak temperature to 800 degrees C to initiate the nanowhisker growth. At 900 degrees C the duration for annealing at peak temperature can be set to 0 s to grow silicon nanowhiskers. A correlation was found between the variation in annealing temperature and duration and the nanowhisker height and density. Annealing at 900 degrees C for 0 s, only 2-3 nanowhiskers (average height 2.4 nm) grow on a surface area of 5 x 5 microm, whereas more than 500 nanowhiskers with an important average height of 4.6 nm for field emission applications grow on the same surface area for a sample annealed at 970 degrees C for 0 s. Selected results are presented showing the possibility of controlling the density and height of Si nanowhisker growth for field emission applications by applying different annealing temperature and duration.

  2. Key technology for (V)HTR: laser beam joining of SiC

    International Nuclear Information System (INIS)

    Knorr, J.; Lippmann, W.; Reinecke, A.M.; Wolf, R.; Rasper, R.; Kerber, A.; Wolter, A.

    2005-01-01

    Laser beam joining has numerous advantages over other methods presently known. After having been developed successful for brazing silicon carbide for high temperature applications, this technology is now also available for silicon nitride. Thus the field of application of SiC and Si 3 N 4 which are very interesting materials for the nuclear sector is considerably extended thanks to this new technology. Ceramic encapsulation of fuel and absorber increases the margins for operation at very high temperatures. Additionally, without ceramic encapsulation of the main core components, it will be difficult to continue claiming non-catastrophic behaviour for the (V)HTR. (orig.)

  3. Heteroepitaxy of zinc-blende SiC nano-dots on Si substrate by organometallic ion beam

    International Nuclear Information System (INIS)

    Matsumoto, T.; Kiuchi, M.; Sugimoto, S.; Goto, S.

    2006-01-01

    The self-assembled SiC nano-dots were fabricated on Si(111) substrate at low-temperatures using the organometallic ion beam deposition technique. The single precursor of methylsilicenium ions (SiCH 3 + ) with the energy of 100 eV was deposited on Si(111) substrate at 500, 550 and 600 deg. C. The characteristics of the self-assembled SiC nano-dots were analyzed by reflection high-energy electron diffraction (RHEED), Raman spectroscopy and atomic force microscope (AFM). The RHEED patterns showed that the crystal structure of the SiC nano-dots formed on Si(111) substrate was zinc-blende SiC (3C-SiC) and it was heteroepitaxy. The self-assembled SiC nano-dots were like a dome in shape, and their sizes were the length of 200-300 nm and the height of 10-15 nm. Despite the low-temperature of 500 deg. C as SiC crystallization the heteroepitaxial SiC nano-dots were fabricated on Si(111) substrate using the organometallic ion beam

  4. Optical and electrical properties of semiconducting BaSi2 thin films on Si substrates grown by molecular beam epitaxy

    International Nuclear Information System (INIS)

    Morita, K.; Inomata, Y.; Suemasu, T.

    2006-01-01

    The electrical properties and optical absorption (OA) spectra of undoped BaSi 2 films grown by molecular beam epitaxy were investigated The electron density and mobility of BaSi 2 grown epitaxially on Si(111) were 5 x 10 15 cm -3 and 820 cm 2 /V.s at room temperature, respectively. The conduction-band discontinuity at the BaSi 2 /Si heterojunction was estimated to be 0.7 eV from the current-voltage characteristics of n-BaSi 2 /n-Si isotype diodes. OA spectra were measured on polycrystalline BaSi 2 films grown on transparent fused silica substrates with predeposited polycrystalline Si layer. The indirect absorption edge was derived to be 1.3 eV, and the optical absorption coefficient reached 10 5 cm -1 at 1.5 eV

  5. Wire Scanner Beam Profile Measurements: LANSCE Facility Beam Development

    International Nuclear Information System (INIS)

    Gilpatrick, John D.; Batygin, Yuri K.; Gonzales, Fermin; Gruchalla, Michael E.; Kutac, Vincent G.; Martinez, Derwin; Sedillo, James Daniel; Pillai, Chandra; Rodriguez Esparza, Sergio; Smith, Brian G.

    2012-01-01

    The Los Alamos Neutron Science Center (LANSCE) is replacing Wire Scanner (WS) beam profile measurement systems. Three beam development tests have taken place to test the new wire scanners under beam conditions. These beam development tests have integrated the WS actuator, cable plant, electronics processors and associated software and have used H - beams of different beam energy and current conditions. In addition, the WS measurement-system beam tests verified actuator control systems for minimum profile bin repeatability and speed, checked for actuator backlash and positional stability, tested the replacement of simple broadband potentiometers with narrow band resolvers, and tested resolver use with National Instruments Compact Reconfigurable Input and Output (cRIO) Virtual Instrumentation. These beam tests also have verified how trans-impedance amplifiers react with various types of beam line background noise and how noise currents were not generated. This paper will describe these beam development tests and show some resulting data.

  6. Wire Scanner Beam Profile Measurements: LANSCE Facility Beam Development

    Energy Technology Data Exchange (ETDEWEB)

    Gilpatrick, John D. [Los Alamos National Laboratory; Batygin, Yuri K. [Los Alamos National Laboratory; Gonzales, Fermin [Los Alamos National Laboratory; Gruchalla, Michael E. [Los Alamos National Laboratory; Kutac, Vincent G. [Los Alamos National Laboratory; Martinez, Derwin [Los Alamos National Laboratory; Sedillo, James Daniel [Los Alamos National Laboratory; Pillai, Chandra [Los Alamos National Laboratory; Rodriguez Esparza, Sergio [Los Alamos National Laboratory; Smith, Brian G. [Los Alamos National Laboratory

    2012-05-15

    The Los Alamos Neutron Science Center (LANSCE) is replacing Wire Scanner (WS) beam profile measurement systems. Three beam development tests have taken place to test the new wire scanners under beam conditions. These beam development tests have integrated the WS actuator, cable plant, electronics processors and associated software and have used H{sup -} beams of different beam energy and current conditions. In addition, the WS measurement-system beam tests verified actuator control systems for minimum profile bin repeatability and speed, checked for actuator backlash and positional stability, tested the replacement of simple broadband potentiometers with narrow band resolvers, and tested resolver use with National Instruments Compact Reconfigurable Input and Output (cRIO) Virtual Instrumentation. These beam tests also have verified how trans-impedance amplifiers react with various types of beam line background noise and how noise currents were not generated. This paper will describe these beam development tests and show some resulting data.

  7. Study of ion beam sputtered Fe/Si interfaces as a function of Si layer thickness

    Science.gov (United States)

    Kumar, Anil; Brajpuriya, Ranjeet; Singh, Priti

    2018-01-01

    The exchange interaction in metal/semiconductor interfaces is far from being completely understood. Therefore, in this paper, we have investigated the nature of silicon on the Fe interface in the ion beam deposited Fe/Si/Fe trilayers keeping the thickness of the Fe layers fixed at 3 nm and varying the thickness of the silicon sandwich layer from 1.5 nm to 4 nm. Grazing incidence x-ray diffraction and atomic force microscopy techniques were used, respectively, to study the structural and morphological changes in the deposited films as a function of layer thickness. The structural studies show silicide formation at the interfaces during deposition and better crystalline structure of Fe layers at a lower spacer layer thickness. The magnetization behavior was investigated using magneto-optical Kerr effect, which clearly shows that coupling between the ferromagnetic layers is highly influenced by the semiconductor spacer layer thickness. A strong antiferromagnetic coupling was observed for a value of tSi = 2.5 nm but above this value an unexpected behavior of hysteresis loop (step like) with two coercivity values is recorded. For spacer layer thickness greater than 2.5 nm, an elemental amorphous Si layer starts to appear in the spacer layer in addition to the silicide layer at the interfaces. It is observed that in the trilayer structure, Fe layers consist of various stacks, viz., Si doped Fe layers, ferromagnetic silicide layer, and nonmagnetic silicide layer at the interfaces. The two phase hysteresis loop is explained on the basis of magnetization reversal of two ferromagnetic layers, independent of each other, with different coercivities. X-ray photo electron spectroscopy technique was also used to study interfaces characteristics as a function of tSi.

  8. Molecular beam epitaxy of InN nanowires on Si

    Science.gov (United States)

    Golam Sarwar, A. T. M.; Carnevale, Santino D.; Kent, Thomas F.; Laskar, Masihhur R.; May, Brelon J.; Myers, Roberto C.

    2015-10-01

    We report on a systematic growth study of the nucleation process of InN nanowires on Si(1 1 1) substrates using plasma assisted molecular beam epitaxy (PAMBE). Samples are grown with various substrate temperatures and III/V ratios. Scanning electron microscopy, X-ray diffraction spectroscopy, energy dispersive X-ray spectroscopy, and photoluminescence are carried out to map out the variation in structural and optical properties versus growth conditions. Statistical averages of areal density, height, and radius are mapped as a function of substrate temperature and III/V ratio. Three different morphological phases are identified on the growth surface: InN, α-In and β-In. Based on SEM image analysis of samples grown at different conditions, the formation mechanism of these phases is proposed. Finally, the growth phase diagram of PAMBE grown InN on Si under N-rich condition is presented, and tapered versus non-tapered growth conditions are identified. It is found that high growth temperature and low III/V ratio plays a critical role in the growth of non-tapered InN nanowires.

  9. Metallization of ion beam synthesized Si/3C-SiC/Si layer systems by high-dose implantation of transition metal ions

    International Nuclear Information System (INIS)

    Lindner, J.K.N.; Wenzel, S.; Stritzker, B.

    2001-01-01

    The formation of metal silicide layers contacting an ion beam synthesized buried 3C-SiC layer in silicon by means of high-dose titanium and molybdenum implantations is reported. Two different strategies to form such contact layers are explored. The titanium implantation aims to convert the Si top layer of an epitaxial Si/SiC/Si layer sequence into TiSi 2 , while Mo implantations were performed directly into the SiC layer after selectively etching off all capping layers. Textured and high-temperature stable C54-TiSi 2 layers with small additions of more metal-rich silicides are obtained in the case of the Ti implantations. Mo implantations result in the formation of the high-temperature phase β-MoSi 2 , which also grows textured on the substrate. The formation of cavities in the silicon substrate at the lower SiC/Si interface due to the Si consumption by the growing silicide phase is observed in both cases. It probably constitutes a problem, occurring whenever thin SiC films on silicon have to be contacted by silicide forming metals independent of the deposition technique used. It is shown that this problem can be solved with ion beam synthesized contact layers by proper adjustment of the metal ion dose

  10. In-beam γ-ray spectroscopy of 38,40,42Si

    Directory of Open Access Journals (Sweden)

    Matsushita M.

    2014-03-01

    Full Text Available Excited states in the nuclei 38,40,42 Si have been studied using in-beam Γ-ray spectroscopy following multi-nucleon removal reactions to investigate the systematics of excitation energies along the Z=14 isotopic chain. The most probable candidates for the transition from the yrast 4+ state were tentatively assigned among several γ lines newly observed in the present study. The energy ratios between the 21+ and 41+ states were obtained to be 2.09(5, 2.56(5 and 2.93(5 for 38,40,42Si, respectively, indicating a rapid development of deformation in Si isotopes from N=24 to, at least, N=28.

  11. Synthesizing single-phase β-FeSi2 via ion beam irradiations of Fe/Si bilayers

    International Nuclear Information System (INIS)

    Milosavljevic, M.; Dhar, S.; Schaaf, P.; Bibic, N.; Lieb, K.P.

    2001-01-01

    This paper presents results on the direct synthesis of the β-FeSi 2 phase by ion beam mixing of Fe/Si bilayers with Xe ions. The influence of the substrate temperature, ion fluence and energy on the growth of this phase was investigated using Rutherford backscattering (RBS), X-ray diffraction (XRD) and conversion electron Moessbauer spectroscopy (CEMS). Complete growth of single-phase β-FeSi 2 was achieved by 205 keV Xe ion irradiation to a fluence of 2x10 16 ions/cm 2 at 600 deg. C. We propose a two-step reaction mechanism involving thermal and ion beam energy deposition

  12. Effect of hydrogen ion beam treatment on Si nanocrystal/SiO_2 superlattice-based memory devices

    International Nuclear Information System (INIS)

    Fu, Sheng-Wen; Chen, Hui-Ju; Wu, Hsuan-Ta; Chuang, Bing-Ru; Shih, Chuan-Feng

    2016-01-01

    Graphical abstract: - Highlights: • Memory window and retention properties are improved employing HIBAS technique. • The O/Si ratio and radiative recombination are changed by HIBAS. • Memory properties are affected not only by Si NCs and O/Si ratio but also the RDCs. • The mechanism of hydrogen ion beam alters the memory properties is investigated. - Abstract: This study presents a novel route for synthesizing silicon-rich oxide (SRO)/SiO_2 superlattice-based memory devices with an improved memory window and retention properties. The SiO_2 and SRO superlattices are deposited by reactive sputtering. Specifically, the hydrogen ion beam is used to irradiate the SRO layer immediately after its deposition in the vacuum chamber. The use of the hydrogen ion beam was determined to increase oxygen content and the density of the Si nanocrystals. The memory window increased from 16 to 25.6 V, and the leakage current decreased significantly by two orders, to under ±20 V, for the hydrogen ion beam-prepared devices. This study investigates the mechanism into how hydrogen ion beam treatment alters SRO films and influences memory properties.

  13. Kinetic study of group IV nanoparticles ion beam synthesized in SiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Bonafos, C. E-mail: bonafos@cemes.fr; Colombeau, B.; Altibelli, A.; Carrada, M.; Ben Assayag, G.; Garrido, B.; Lopez, M.; Perez-Rodriguez, A.; Morante, J.R.; Claverie, A

    2001-05-01

    Most studies concerning group IV (Si, Ge) ion beam synthesized nanocrystals in SiO{sub 2} have shown that a link exists between the observed physical properties and the characteristics of the 'populations' of nanoparticles (size-distribution, density, volume fraction). The aim of this paper is to study the influence of the initial supersaturation and annealing conditions on these characteristics. For this, experimental methods have been developed, that allow accurate statistical studies. Different transmission electron microscopy (TEM) imaging conditions have been tested and the most adequate ones have been identified for each system. An original method for the measurement of the density of precipitates embedded in an amorphous matrix has been developed and tested for Ge precipitates in SiO{sub 2} and has permitted to evidence a conservative Ostwald ripening during annealing. The kinetic behavior of Si nanoparticles has also been studied by coupling TEM measurements and 'atomistic' simulations. During annealing, the growth of these nanoparticles is very slow but their size significantly increases when increasing the initial Si excess. Simulations are in perfect agreement with experiment when taking into account interaction effects between particles.

  14. Fabrication of FeSi and Fe{sub 3}Si compounds by electron beam induced mixing of [Fe/Si]{sub 2} and [Fe{sub 3}/Si]{sub 2} multilayers grown by focused electron beam induced deposition

    Energy Technology Data Exchange (ETDEWEB)

    Porrati, F.; Sachser, R.; Huth, M. [Physikalisches Institut, Goethe-Universität, Max-von-Laue-Str. 1, D-60438 Frankfurt am Main (Germany); Gazzadi, G. C. [S3 Center, Nanoscience Institute-CNR, Via Campi 213/a, 41125 Modena (Italy); Frabboni, S. [S3 Center, Nanoscience Institute-CNR, Via Campi 213/a, 41125 Modena (Italy); FIM Department, University of Modena and Reggio Emilia, Via G. Campi 213/a, 41125 Modena (Italy)

    2016-06-21

    Fe-Si binary compounds have been fabricated by focused electron beam induced deposition by the alternating use of iron pentacarbonyl, Fe(CO){sub 5}, and neopentasilane, Si{sub 5}H{sub 12} as precursor gases. The fabrication procedure consisted in preparing multilayer structures which were treated by low-energy electron irradiation and annealing to induce atomic species intermixing. In this way, we are able to fabricate FeSi and Fe{sub 3}Si binary compounds from [Fe/Si]{sub 2} and [Fe{sub 3}/Si]{sub 2} multilayers, as shown by transmission electron microscopy investigations. This fabrication procedure is useful to obtain nanostructured binary alloys from precursors which compete for adsorption sites during growth and, therefore, cannot be used simultaneously.

  15. Influence of ion beam and geometrical parameters on properties of Si thin films grown by Ar ion beam sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Bundesmann, Carsten; Feder, Rene; Neumann, Horst [Leibniz-Institut fuer Oberflaechenmodifizierung e.V., Leipzig (Germany)

    2012-07-01

    Ion beam sputtering (IBS) offers, in contrast to other physical vapour deposition techniques, such as magnetron sputtering or electron beam evaporation, the opportunity to change the properties of the layer forming particles (sputtered and scattered particles) by varying ion beam parameters (ion species, ion energy) and geometrical parameters (ion incidence angle, emission angle). Consequently, these effects can be utilized to tailor thin film properties [1]. The goal is to study systematically the correlations between the primary and secondary parameters and, at last, the effects on the properties of Si thin films, such as optical properties, stress, surface topography and composition. First experimental results are presented for Ar-ion sputtering of Si.

  16. Quantitative SIMS analysis of SiGe composition with low energy O2+ beams

    International Nuclear Information System (INIS)

    Jiang, Z.X.; Kim, K.; Lerma, J.; Corbett, A.; Sieloff, D.; Kottke, M.; Gregory, R.; Schauer, S.

    2006-01-01

    This work explored quantitative analyses of SiGe films on either Si bulk or SOI wafers with low energy SIMS by assuming a constant ratio between the secondary ion yields of Si + and Ge + inside SiGe films. SiGe samples with Ge contents ranging from 15 to 65% have been analyzed with a 1 keV O 2 + beam at normal incidence. For comparison, the samples were also analyzed with RBS and/or AES. The Ge content as measured with SIMS, based on a single SiGe/Si or SiGe/SOI standard, exhibited good agreement with the corresponding RBS and AES data. It was concluded that SIMS was capable of providing accurate characterization of the SiGe composition with the Ge content up to 65%

  17. Structural and electrical characterization of ion beam synthesized and n-doped SiC layers

    Energy Technology Data Exchange (ETDEWEB)

    Serre, C.; Perez-Rodriguez, A.; Romano-Rodriguez, A.; Morante, J.R. [Barcelona Univ. (Spain). Dept. Electronica; Panknin, D.; Koegler, R.; Skorupa, W. [Forschungszentrum Rossendorf, Dresden (Germany); Esteve, J.; Acero, M.C. [CSIC, Bellaterra (Spain). Centre Nacional de Microelectronica

    2001-07-01

    This work reports preliminary data on the ion beam synthesis of n-doped SiC layers. For this, two approaches have been studied: (i) doping by ion implantation (with N{sup +}) of ion beam synthesized SiC layers and (ii) ion beam synthesis of SiC in previously doped (with P) Si wafers. In the first case, the electrical data show a p-type overcompensation of the SiC layer in the range of temperatures between -50 C and 125 C. The structural (XRD) and in-depth (SIMS, Spreading Resistance) analysis of the samples suggest this overcompensation to be induced by p-type active defects related to the N{sup +} ion implantation damage, and therefore the need for further optimization their thermal processing. In contrast, the P-doped SiC layers always show n-type doping. This is also accompanied by a higher structural quality, being the spectral features of the layers similar to those from the not doped material. Electrical activation of P in the SiC lattice is about one order of magnitude lower than in Si. These data constitute, to our knowledge, the first results reported on the doping of ion beam synthesized SiC layers. (orig.)

  18. Monolithic integration of AlGaInP laser diodes on SiGe/Si substrates by molecular beam epitaxy

    International Nuclear Information System (INIS)

    Kwon, O.; Boeckl, J. J.; Lee, M. L.; Pitera, A. J.; Fitzgerald, E. A.; Ringel, S. A.

    2006-01-01

    Room temperature operation of visible AlGaInP laser diodes epitaxially integrated on Si was demonstrated. Compressively strained laser heterostructures were grown by molecular beam epitaxy (MBE) on low dislocation density SiGe/Si substrates, where the threading dislocation density of the top relaxed Ge layers was measured in the range of 2x10 6 cm -2 . A threshold current density of J th ∼1.65 kA/cm 2 for the as-cleaved, gain-guided AlGaInP laser grown on SiGe/Si was obtained at the peak emission wavelength of 680 nm under pulsed mode current injection. These results show that not only can high quality AlGaInP materials grown by MBE be achieved on Si via relaxed SiGe interlayers, but the prototype demonstration of laser diode operation on Si illustrates that very defect sensitive optoelectronics in the III-P system can indeed be integrated with Si substrates by heteroepitaxial methods

  19. Gas cluster ion beam assisted NiPt germano-silicide formation on SiGe

    Energy Technology Data Exchange (ETDEWEB)

    Ozcan, Ahmet S., E-mail: asozcan@us.ibm.com [IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120 (United States); Lavoie, Christian; Jordan-Sweet, Jean [IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598 (United States); Alptekin, Emre; Zhu, Frank [IBM Semiconductor Research and Development Center, 2070 Route 52, Hopewell Junction, New York 12533 (United States); Leith, Allen; Pfeifer, Brian D.; LaRose, J. D.; Russell, N. M. [TEL Epion Inc., 900 Middlesex Turnpike, Bldg. 6, Billerica, Massachusetts 01821 (United States)

    2016-04-21

    We report the formation of very uniform and smooth Ni(Pt)Si on epitaxially grown SiGe using Si gas cluster ion beam treatment after metal-rich silicide formation. The gas cluster ion implantation process was optimized to infuse Si into the metal-rich silicide layer and lowered the NiSi nucleation temperature significantly according to in situ X-ray diffraction measurements. This novel method which leads to more uniform films can also be used to control silicide depth in ultra-shallow junctions, especially for high Ge containing devices, where silicidation is problematic as it leads to much rougher interfaces.

  20. Study of Si wafer surfaces irradiated by gas cluster ion beams

    International Nuclear Information System (INIS)

    Isogai, H.; Toyoda, E.; Senda, T.; Izunome, K.; Kashima, K.; Toyoda, N.; Yamada, I.

    2007-01-01

    The surface structures of Si (1 0 0) wafers subjected to gas cluster ion beam (GCIB) irradiation have been analyzed by cross-sectional transmission electron microscopy (XTEM) and atomic force microscopy (AFM). GCIB irradiation is a promising technique for both precise surface etching and planarization of Si wafers. However, it is very important to understand the crystalline structure of Si wafers after GCIB irradiation. An Ar-GCIB used for the physically sputtering of Si atoms and a SF 6 -GCIB used for the chemical etching of the Si surface are also analyzed. The GCIB irradiation increases the surface roughness of the wafers, and amorphous Si layers are formed on the wafer surface. However, when the Si wafers are annealed in hydrogen at a high temperature after the GCIB irradiation, the surface roughness decreases to the same level as that before the irradiation. Moreover, the amorphous Si layers disappear completely

  1. Interfacial stability of CoSi2/Si structures grown by molecular beam epitaxy

    Science.gov (United States)

    George, T.; Fathauer, R. W.

    1992-01-01

    The stability of CoSi2/Si interfaces was examined in this study using columnar silicide structures grown on (111) Si substrates. In the first set of experiments, Co and Si were codeposited using MBE at 800 C and the resulting columnar silicide layer was capped by epitaxial Si. Deposition of Co on the surface of the Si capping layer at 800 C results in the growth of the buried silicide columns. The buried columns grow by subsurface diffusion of the deposited Co, suppressing the formation of surface islands of CoSi2. The column sidewalls appear to be less stable than the top and bottom interfaces, resulting in preferential lateral growth and ultimately in the coalescence of the columns to form a continuous buried CoSi2 layer. In the second set of experiments, annealing of a 250 nm-thick buried columnar layer at 1000 C under a 100 nm-thick Si capping layer results in the formation of a surface layer of CoSi2 with a reduction in the sizes of the CoSi2 columns. For a sample having a thicker Si capping layer the annealing leads to Ostwald ripening producing buried equiaxed columns. The high CoSi2/Si interfacial strain could provide the driving force for the observed behavior of the buried columns under high-temperature annealing.

  2. The Growth of GaN on Si by the Beam Flux Modulation

    International Nuclear Information System (INIS)

    Roh, C. H.; Ha, M. W.; Song, H. J.; Choi, H. G.; Lee, J. H.; Ra, Y. W.; Hahn, C. K.

    2011-01-01

    AlGaN/GaN HEMT structure was grown on Si (111) substrate by plasma-assisted molecular beam epitaxy (PA-MBE) using a beam flux modulation methods. In this result, it was verified that the propagation of treading dislocation (TD) due to N-rich GaN layer was effectively suppressed.

  3. Development of the fabrication process of SiC composite by polycarbosilane

    International Nuclear Information System (INIS)

    Park, Ji Yeon; Kim, Weon Ju; Kim, Jung Il; Ryu, Woo Seog

    2004-11-01

    This technical report reviewed the fabrication process of fiber reinforced ceramic composites, characteristics of the PIP process, and applications of SiC f /SiC composite to develop a silicon carbide composite by PIP method. Additionally, characteristics and thermal behaviors of a PCS+SiC powder slurry and infiltration behaviors of slurry into the SiC fabric was evaluated. The stacking behaviors of SiC fabrics infiltrated a PCS+SiC powder slurry was also investigated. Using this stacked preforms, SiC f /SiC composites were fabricated by the electron beam curing and pyrolysis process and the thermal oxidation curing and pyrolysis process, respectively. And the characteristics of both composites were compared

  4. Developments in non-destructive beam diagnostics

    International Nuclear Information System (INIS)

    Fraser, J.S.

    1981-01-01

    With the large average beam currents being achieved in accelerators and storage rings, there is an increasing need for non-destructive beam diagnostic devices. For continuous beams, position monitors of the capacitive pick-up type are replaced by resonant devices that respond to the transverse displacement of the beam centroid. Bunch length monitors of the SLAC type using resonant cavities operating in the TM 010 mode can be used for continuous beams. The more detailed information derivable from beam profile scanners requires development of improved non-destructive devices. Profile monitors which scan the visible light produced by high current beams may be more reliable than ones using the residual ionization if the light intensity from gas molecules following nonionizing collisions with beam particles gives a measure of the beam current density independent of the local electron density. The intense Balmer series lines from neutral hydrogen beams have been used successfully to measure beam profiles. At CRNL and at LASL, beam light profile monitors are being developed for high average current accelerators. Three or more projections will be recorded to allow tomographic reconstruction of the two-dimensional beam current density. Light detection is either by intensified Reticons or ISIT vidicons. The use of three or more beam light monitors on a beam transport line will also permit estimates of the transverse emittance to be made through the reconstruction technique

  5. Structural and electrical properties of epitaxial Si layers prepared by E-beam evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Dogan, P. [Hahn-Meitner-Institut Berlin, Kekulestr. 5, 12489 Berlin (Germany)], E-mail: pinar.dogan@hmi.de; Rudigier, E.; Fenske, F.; Lee, K.Y.; Gorka, B.; Rau, B.; Conrad, E.; Gall, S. [Hahn-Meitner-Institut Berlin, Kekulestr. 5, 12489 Berlin (Germany)

    2008-08-30

    In this work, we present structural and electrical properties of thin Si films which are homoepitaxially grown at low substrate temperatures (T{sub s} 450-700 deg. C) by high-rate electron beam evaporation. As substrates, monocrystalline Si wafers with (100) and (111) orientations and polycrystalline Si (poly-Si) seed layers on glass were used. Applying Secco etching, films grown on Si(111) wafers exhibit a decreasing etch pit density with increasing T{sub s}. The best structural quality of the films was obtained on Si(100) wafers. Defect etching on epitaxially grown poly-Si absorbers reveal regions with different crystalline quality. Solar cells have been prepared on both wafers and seed layers. Applying Rapid Thermal Annealing (RTA) and Hydrogen plasma passivation an open circuit voltage of 570 mV for wafer based and 346 mV for seed layer based solar cells have been reached.

  6. Thermally induced formation of SiC nanoparticles from Si/C/Si multilayers deposited by ultra-high-vacuum ion beam sputtering

    International Nuclear Information System (INIS)

    Chung, C-K; Wu, B-H

    2006-01-01

    A novel approach for the formation of SiC nanoparticles (np-SiC) is reported. Deposition of Si/C/Si multilayers on Si(100) wafers by ultra-high-vacuum ion beam sputtering was followed by thermal annealing in vacuum for conversion into SiC nanoparticles. The annealing temperature significantly affected the size, density, and distribution of np-SiC. No nanoparticles were formed for multilayers annealed at 500 0 C, while a few particles started to appear when the annealing temperature was increased to 700 0 C. At an annealing temperature of 900 0 C, many small SiC nanoparticles, of several tens of nanometres, surrounding larger submicron ones appeared with a particle density approximately 16 times higher than that observed at 700 0 C. The higher the annealing temperature was, the larger the nanoparticle size, and the higher the density. The higher superheating at 900 0 C increased the amount of stable nuclei, and resulted in a higher particle density compared to that at 700 0 C. These particles grew larger at 900 0 C to reduce the total surface energy of smaller particles due to the higher atomic mobility and growth rate. The increased free energy of stacking defects during particle growth will limit the size of large particles, leaving many smaller particles surrounding the large ones. A mechanism for the np-SiC formation is proposed in this paper

  7. Model for efficient visible emission from Si nanocrystals ion beam synthesized in SiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, M. E-mail: mlopez@el.ub.es; Garrido, B.; Bonafos, C.; Perez-Rodriguez, A.; Morante, J.R.; Claverie, A

    2001-05-01

    The photoluminescence (PL) emission of Si nanocrystals ion beam synthesized in SiO{sub 2} is studied in this work as a function of annealing time and initial Si atomic excess (super-saturation). The optical properties of this system have been correlated with the characteristics of the nanocrystal population. The Si nanocrystals show a wide and very intense PL red/infrared emission. This emission peaks at about 1.7 eV for the low super-saturation range between 1% and 10% and shifts to the infrared for higher super-saturation (20% and 30%). Remarkably, there is a linear increase of PL intensity versus super-saturation in the low range. Moreover, the annealing kinetic studies show a typical behavior of PL intensity with annealing time, with a fast transitory increase that bends over to reach asymptotic saturation. The PL intensity saturation is satisfactorily explained by the Ostwald ripening stage of the nanocrystal population while the transient stage is a consequence of both nanocrystal growth and nanocrystal surface passivation mechanisms acting together. Indeed, electron spin resonance measurements demonstrate that the concentration of P{sub b} centers (Si dangling bonds) at the Si-SiO{sub 2} interface correlates inversely with PL intensity during most of the transient stage.

  8. Ion-beam synthesis and photoluminescence of SiC nanocrystals assisted by MeV-heavy-ion-beam annealing

    International Nuclear Information System (INIS)

    Khamsuwan, J.; Intarasiri, S.; Kirkby, K.; Chu, P.K.; Singkarat, S.; Yu, L.D.

    2012-01-01

    This work explored a novel way to synthesize silicon carbide (SiC) nanocrystals for photoluminescence. Carbon ions at 90 keV were implanted in single crystalline silicon wafers at elevated temperature, followed by irradiation using xenon ion beams at an energy of 4 MeV with two low fluences of 5 × 10 13 and 1 × 10 14 ions/cm 2 at elevated temperatures for annealing. X-ray diffraction, Raman scattering, infrared spectroscopy and transmission electron microscopy were used to characterize the formation of nanocrystalline SiC. Photoluminescence was measured from the samples. The results demonstrated that MeV-heavy-ion-beam annealing could indeed induce crystallization of SiC nanocrystals and enhance emission of photoluminescence with violet bands dominance due to the quantum confinement effect.

  9. Ion beam synthesis of semiconductor nanoparticles for Si based optoelectronic devices

    International Nuclear Information System (INIS)

    Gonzalez-Varona, O.; Perez-Rodriguez, A.; Garrido, B.; Bonafos, C.; Lopez, M.; Morante, J.R.; Montserrat, J.; Rodriguez, R.

    2000-01-01

    Intense white (to the eye) luminescence has been obtained by multiple implantation of Si + and C + ions into thermal SiO 2 and a post-implantation annealing process. This white emission is a consequence of the convolution of three luminescence peaks centred at about 1.45 eV (infrared with a long tail in the red), 2.1 eV (yellow) and 2.8 eV (blue). These emissions have been correlated to the synthesis of nanocrystals of Si and SiC, and the existence of C-rich precipitates. Cross section TEM shows a buried layer with dark contrast, which correlates with the maximum of the C implanted profile, and likely with a high density of C-rich amorphous domains. Besides, two kinds of nanocrystalline precipitates are found, which have been identified as Si and hexagonal 6H-SiC by electron diffraction experiments. To our knowledge, these data provide the first experimental evidence on the ion beam synthesis of nanocrystalline 6H-SiC embedded in SiO 2 . Correlation with previous data gives support to the assignment of the infrared, yellow and blue peaks with the Si, C-rich and SiC precipitate phases and/or its interfaces with SiO 2

  10. Ion beam synthesis of semiconductor nanoparticles for Si based optoelectronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Varona, O.; Perez-Rodriguez, A.; Garrido, B.; Bonafos, C.; Lopez, M.; Morante, J.R.; Montserrat, J.; Rodriguez, R

    2000-03-01

    Intense white (to the eye) luminescence has been obtained by multiple implantation of Si{sup +} and C{sup +} ions into thermal SiO{sub 2} and a post-implantation annealing process. This white emission is a consequence of the convolution of three luminescence peaks centred at about 1.45 eV (infrared with a long tail in the red), 2.1 eV (yellow) and 2.8 eV (blue). These emissions have been correlated to the synthesis of nanocrystals of Si and SiC, and the existence of C-rich precipitates. Cross section TEM shows a buried layer with dark contrast, which correlates with the maximum of the C implanted profile, and likely with a high density of C-rich amorphous domains. Besides, two kinds of nanocrystalline precipitates are found, which have been identified as Si and hexagonal 6H-SiC by electron diffraction experiments. To our knowledge, these data provide the first experimental evidence on the ion beam synthesis of nanocrystalline 6H-SiC embedded in SiO{sub 2}. Correlation with previous data gives support to the assignment of the infrared, yellow and blue peaks with the Si, C-rich and SiC precipitate phases and/or its interfaces with SiO{sub 2}.

  11. Beam chopper development at LAMPF

    International Nuclear Information System (INIS)

    Hutson, R.L.; Cooke, D.W.; Heffner, R.H.; Schillaci, M.E.; Dodds, S.A.; Gist, G.A.

    1986-01-01

    In order to reduce pileup limitations on μSR data rates, a fast chopper for surface muon beams was built and tested at LAMPF. The system allowed one muon at a time to be stopped in a μSR sample in the following way: A surface beam from the LAMPF Stopped Muon Channel was focused through a crossed-field beam separator and onto a chopper slit. With the separator E and B fields adjusted properly, the beam could pass through the slit. The beam to the μSR sample was turned on or off (chopped) rapidly by switching the high voltage applied to the separator plates on or off within approximately 500 ns; with the E field off, the B field deflected the beam, dumping it near the slit. We demonstrated that, with improved electronics, we will be able to stop a single muon in a μSR sample as frequently as once every 20 μs and that data rates for the system can be a factor of five higher than is attainable with unchopped beams. The observed positron contamination of the beam was less than five percent, and the ratio of the muon rate with beam on to the rate with beam off was 1540

  12. Beam chopper development at LAMPF

    International Nuclear Information System (INIS)

    Hutson, R.L.; Cooke, D.W.; Heffner, R.H.; Schillaci, M.E.; Dodds, S.A.; Gist, G.A.

    1986-01-01

    In order to reduce pileup limitations on μSR data rates, a fast chopper for surface muon beams was built and tested at LAMPF. The system allowed one muon at a time to be stopped in a μSR sample in the following way: A surface beam from the LAMPF Stopped Muon Channel was focused through a crossed-field beam separator and onto a chopper slit. With the separator E and B fields adjusted properly, the beam could pass through the slit. The beam to the μSR sample was turned on or off (chopped) rapidly by switching the high voltage applied to the separator plates on or off within approximately 500 ns; with the E field off, the B field deflected the beam, dumping it near the slit. We demonstrated that, with improved electronics, we will be able to stop a single muon in a μSR sample as frequently as once every 20 μs and that data rates for the system can be a factor of five higher than is attainable with unchopped beams. The observed positron contamination of the beam was less than five percent, and the ratio of the muon rate with beam on to the rate with beam off was 1540. (orig.)

  13. Investigation based on nano-electromechanical system double Si3N4 resonant beam pressure sensor.

    Science.gov (United States)

    Yang, Chuan; Guo, Can; Yuan, Xiaowei

    2011-12-01

    This paper presents a type of NEMS (Nano-Electromechanical System) double Si3N4 resonant beams pressure sensor. The mathematical models are established in allusion to the Si3N4 resonant beams and pressure sensitive diaphragm. The distribution state of stress has been analyzed theoretically based on the mathematical model of pressure sensitive diaphragm; from the analysis result, the position of the Si3N4 resonant beams above the pressure sensitive diaphragm was optimized and then the dominance observed after the double resonant beams are adopted is illustrated. From the analysis result, the position of the Si3N4 resonant beams above the pressure sensitive diaphragm is optimized, illustrating advantages in the adoption of double resonant beams. The capability of the optimized sensor was generally analyzed using the ANSYS software of finite element analysis. The range of measured pressure is 0-400 Kpa, the coefficient of linearity correlation is 0.99346, and the sensitivity of the sensor is 498.24 Hz/Kpa, higher than the traditional sensors. Finally the processing techniques of the sensor chip have been designed with sample being successfully processed.

  14. Development of high-spin isomer beams

    International Nuclear Information System (INIS)

    Zhou Xiaohong

    2000-01-01

    The physical motivations with high-spin isomer beams were introduced. Taking HSIB of RIKEN as an example, the methods to produce, separate, transport and purity high-spin isomer beams were described briefly, and the detection of γ rays emitted from the reactions induced by the high-spin isomer beams was presented. Finally, the progress to develop the high-spin isomers in the N = 83 isotones as second beams was stressed

  15. Combined sputtering yield and surface topography development studies on Si

    International Nuclear Information System (INIS)

    Carter, G.; Nobes, M.J.; Lewis, G.W.; Whitton, J.L.

    1981-01-01

    The sputtering yield-incidence angle function has been measured for 8 keV Ar + ions incident on Si by direct scanning electron microscope observation of the depths of sputtered craters on substrate boundaries. This function displays a maximum sputtering yield at an angle thetasub(p) approximately equal to 40 0 to the surface normal. The sequential ion fluence dependence of features developed beneath local surface contaminant was then studied, quasi dynamically, in the same on-line ion source-S.E.M. system. During erosion of the contaminant a steeply elevated pillar of Si forms, which then transforms to a cone, again of high elevation angle >>thetasub(p). This cone is gradually eroded into the surrounding surface with no special significance associated with orientations of angle thetasub(p). Pedal depressions surrounding the pillar-cone system are also noted. The reasons for these observations and their relevance to ion beam surface channel etching are discussed. (Auth.)

  16. Fabrication of bright and thin Zn₂SiO₄ luminescent film for electron beam excitation-assisted optical microscope.

    Science.gov (United States)

    Furukawa, Taichi; Kanamori, Satoshi; Fukuta, Masahiro; Nawa, Yasunori; Kominami, Hiroko; Nakanishi, Yoichiro; Sugita, Atsushi; Inami, Wataru; Kawata, Yoshimasa

    2015-07-13

    We fabricated a bright and thin Zn₂SiO₄ luminescent film to serve as a nanometric light source for high-spatial-resolution optical microscopy based on electron beam excitation. The Zn₂SiO₄ luminescent thin film was fabricated by annealing a ZnO film on a Si₃N₄ substrate at 1000 °C in N₂. The annealed film emitted bright cathodoluminescence compared with the as-deposited film. The film is promising for nano-imaging with electron beam excitation-assisted optical microscopy. We evaluated the spatial resolution of a microscope developed using this Zn₂SiO₄ luminescent thin film. This is the first report of the investigation and application of ZnO/Si₃N₄ annealed at a high temperature (1000 °C). The fabricated Zn₂SiO₄ film is expected to enable high-frame-rate dynamic observation with ultra-high resolution using our electron beam excitation-assisted optical microscopy.

  17. Development of high current electron beam generator

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Byeong Cheol; Lee, Jong Min; Kim, Sun Kook [and others

    1997-05-01

    A high-current electron beam generator has been developed. The energy and the average current of the electron beam are 2 MeV and 50 mA, respectively. The electron beam generator is composed of an electron gun, RF acceleration cavities, a 260-kW RF generator, electron beam optics components, and control system, etc. The electron beam generator will be used for the development of a millimeter-wave free-electron laser and a high average power infrared free-electron laser. The machine will also be used as a user facility in nuclear industry, environment industry, semiconductor industry, chemical industry, etc. (author). 15 tabs., 85 figs.

  18. Development of high current electron beam generator

    International Nuclear Information System (INIS)

    Lee, Byeong Cheol; Lee, Jong Min; Kim, Sun Kook

    1997-05-01

    A high-current electron beam generator has been developed. The energy and the average current of the electron beam are 2 MeV and 50 mA, respectively. The electron beam generator is composed of an electron gun, RF acceleration cavities, a 260-kW RF generator, electron beam optics components, and control system, etc. The electron beam generator will be used for the development of a millimeter-wave free-electron laser and a high average power infrared free-electron laser. The machine will also be used as a user facility in nuclear industry, environment industry, semiconductor industry, chemical industry, etc. (author). 15 tabs., 85 figs

  19. Strain-symmetrized Si/SiGe multi-quantum well structures grown by molecular beam epitaxy for intersubband engineering

    International Nuclear Information System (INIS)

    Zhao, M.; Karim, A.; Ni, W.-X.; Pidgeon, C.R.; Phillips, P.J.; Carder, D.; Murdin, B.N.; Fromherz, T.; Paul, D.J.

    2006-01-01

    Three strain-symmetrized Si/SiGe multi-quantum well structures, designed for probing the carrier lifetime of intrawell intersubband transitions between heavy hole 1 (HH1) and light hole 1 (LH1) states with transition energies below the optical phonon energy, were grown by molecular beam epitaxy at low temperature on fully relaxed SiGe virtual substrates. The grown structures were characterized by using various experimental techniques, showing a high crystalline quality and very precise growth control. The lifetime of the LH1 excited state was determined directly with pump-probe spectroscopy. The measurements indicated an increase of the lifetime by a factor of ∼2 due to the increasingly unconfined LH1 state, which agreed very well with the design. It also showed a very long lifetime of several hundred picoseconds for the holes excited out of the well to transit back to the well through a diagonal process

  20. High-rate deposition of SI absorber layers by electron beam evaporation and first electron beam crystallization tests

    OpenAIRE

    Saager, Stefan; Ben Yaala, Marwa; Heinß, Jens-Peter; Temmler, Dietmar; Pfefferling, Bert; Metzner, Christoph

    2014-01-01

    In earlier electron beam physical vapor deposition tests (EB-PVD), using a conventional copper crucible (A), high Si deposition rates at relatively high EB power together with a contamination level of 1016 cm-3 are demonstrated. To improve the rate vs. EB power relation as well as the Si layer purity, two alternative high rate EBPVD methods are investigated and reported here - a contact-less crucible setup (B) and a crucible-free setup (C).In these experiments comparable deposition rates of ~...

  1. Defect distribution in low-temperature molecular beam epitaxy grown Si/Si(100), improved depth profiling with monoenergetic positrons

    International Nuclear Information System (INIS)

    Szeles, C.; Asoka-Kumar, P.; Lynn, K.G.; Gossmann, H.; Unterwald, F.C.; Boone, T.

    1995-01-01

    The depth distribution of open-volume defects has been studied in Si(100) crystals grown by molecular beam epitaxy at 300 degree C by the variable-energy monoenergetic positron beam technique combined with well-controlled chemical etching. This procedure gave a 10 nm depth resolution which is a significant improvement over the inherent depth resolving power of the positron beam technique. The epitaxial layer was found to grow defect-free up to 80 nm, from the interface, where small vacancy clusters, larger than divacancies, appear. The defect density then sharply increases toward the film surface. The result clearly shows that the nucleation of small open-volume defects is a precursor state to the breakdown of epitaxy and to the evolution of an amorphous film

  2. Microstructural changes in silicon induced by patterning with focused ion beams of Ga, Si and Au

    International Nuclear Information System (INIS)

    Chee, See Wee; Kammler, Martin; Balasubramanian, Prabhu; Reuter, Mark C.; Hull, Robert; Ross, Frances M.

    2013-01-01

    We use focused beams of Ga + , Au + and Si ++ ions to induce local microstructural changes in single crystal silicon. The ions were delivered as single spot pulses into thin Si membranes that could subsequently be imaged and annealed in situ in a transmission electron microscope. For each ion, the focused ion beam implantation created an array of amorphous regions in the crystalline membrane. Annealing causes solid phase epitaxial regrowth to take place, but we show that the resulting microstructure depends on the ion species. For Ga + and Au + , precipitates remain after recrystallization, while for Si ++ , dislocation loops form around the periphery of each implanted spot. We attribute these loops to defects formed during solid phase epitaxial regrowth, with controlled placement of the loops possible. - Highlights: ► Ga + , Au + and Si ++ were implanted into thin membranes of Si. ► Samples were imaged and annealed in situ in a transmission electron microscope. ► Focused ion beam implantation created an array of amorphous spots. ► After recrystallization, precipitates form for Ga + and Au + , dislocation loops for Si ++ . ► Controlled placement of the dislocation loops possible

  3. Si Micro-turbine by Proton BeamWriting and Porous Silicon Micromachining

    International Nuclear Information System (INIS)

    Rajta, I.; Szilasi, S.Z.; Fekete, Z.

    2008-01-01

    Complete text of publication follows. A 3D Si micro-turbine characterized by high aspect ratio vertical walls was formed by the combination of proton beam writing (PBW) and subsequent selective porous Si (PS) etching. Crystal damages generated by the implanted protons result in increased resistivity, thereby limit or even prevent the current to flow through the implanted area during electrochemical etching. Characteristic feature of the proposed process is that the shape of the micro electromechanical (MEMS) components is defined by two implantation energies. A higher energy is applied for defining the housing of the device while the lower energy is used to write the moving components. The implantation energies were selected such as to result appropriate difference between the two projected ranges, thereby providing structures with different height after development. The thickness of the walls of the moving component and the isotropic etching profile of the electrochemical PS formation was also taken into consideration. The electrochemical etching is driven until the sacrificial PS layer completely under etches the moving components, but the etch-front does not reach the bottom of the housing. Therefore, the dissolution of PS results in a ready-to-operate device with a released moving component embedded in the cavity of the housing. The operation of the encapsulated device fabricated by the two-energy implantation is successfully demonstrated (Fig. 1). Rotation speed of the device is estimated in the range of thousands rpm, however, further analysis of the novel structure optimized for performance and MEMS compatible assembly will be done and precise characteristics will be determined by adequate optical read-out method. The feasibility of Proton Beam Writing combined with Porous Si Micromachining and conventional Si processing steps was successfully demonstrated by fabricating Si microturbine chip. The aligned, two-energy proton beam implantation can provide high

  4. Surface hardening of 30CrMnSiA steel using continuous electron beam

    Science.gov (United States)

    Fu, Yulei; Hu, Jing; Shen, Xianfeng; Wang, Yingying; Zhao, Wansheng

    2017-11-01

    30CrMnSiA high strength low alloy (HSLA) carbon structural steel is typically applied in equipment manufacturing and aerospace industries. In this work, the effects of continuous electron beam treatment on the surface hardening and microstructure modifications of 30CrMnSiA are investigated experimentally via a multi-purpose electron beam machine Pro-beam system. Micro hardness value in the electron beam treated area shows a double to triple increase, from 208 HV0.2 on the base metal to 520 HV0.2 on the irradiated area, while the surface roughness is relatively unchanged. Surface hardening parameters and mechanisms are clarified by investigation of the microstructural modification and the phase transformation both pre and post irradiation. The base metal is composed of ferrite and troostite. After continuous electron beam irradiation, the micro structure of the electron beam hardened area is composed of acicular lower bainite, feathered upper bainite and part of lath martensite. The optimal input energy density for 30CrMnSiA steel in this study is of 2.5 kJ/cm2 to attain the proper hardened depth and peak hardness without the surface quality deterioration. When the input irradiation energy exceeds 2.5 kJ/cm2 the convective mixing of the melted zone will become dominant. In the area with convective mixing, the cooling rate is relatively lower, thus the micro hardness is lower. The surface quality will deteriorate. Chemical composition and surface roughness pre and post electron beam treatment are also compared. The technology discussed give a picture of the potential of electron beam surface treatment for improving service life and reliability of the 30CrMnSiA steel.

  5. Preparation of SiC thin films by ion beam technology and PECVD

    International Nuclear Information System (INIS)

    Chen Changqing; Ren Congxin; Yang Lixin; Yan Jinlong; Zheng Zhihong; Zhou Zuyao; Chen Ping; Liu Xianghuai; Chen Xueliang

    1998-01-01

    The formation of β-SiC buried layers in p-type Si by ion beam methods is reported and a comparison of the results obtained under different experimental conditions is made. The preparation of amorphous SiC thin films by IBED is presented and the enhanced deposition of Xe + is found superior to that of Ar + . The work of synthesizing hydrogenated amorphous SiC films by RIBS and RIBAD is described with a discussion on the dependence of some physical parameters on the partial pressure ratio pCH 4 /pAr. Finally given is a brief introduction to a high quality α-SiC:H film which is prepared by PECVD and can exhibit green luminescence at room temperature

  6. Porous SiC/SiC composites development for industrial application

    International Nuclear Information System (INIS)

    Maeta, S.; Hinoki, T.

    2014-01-01

    Silicon carbide (SiC) is promising structural materials in nuclear fields due to an excellent irradiation resistance and low activation characteristics. Conventional SiC fibers reinforced SiC matrix (SiC/SiC composites) fabricated by liquid phase sintering (LPS-SiC/SiC composites) have been required high cost and long processing time. And microstructure and mechanical property data of finally obtained LPS-SiC/SiC composites are easily scattered, because quality of the composites depend on personal skill. Thus, conventional LPS-SiC/SiC composites are inadequate for industrial use. In order to overcome these issues, the novel “porous SiC/SiC composites” have been developed by means of liquid phase sintering fabrication process. The composites consist of porous SiC matrix and SiC fibers without conventional carbon interfacial layer. The composites don’t have concerns of the degradation interfacial layer at the severe accident. Porous SiC/SiC composites preform was prepared with a thin sheet shape of SiC, sintering additives and carbon powder mixture by tape casting process which was adopted because of productive and high yielding rate fabrication process. The preform was stacked with SiC fibers and sintered in hot-press at the high temperature in argon environment. The sintered preform was decarburized obtain porous matrix structure by heat-treatment in air. Moreover, mechanical property data scattering of the obtained porous SiC/SiC composites decreased. In the flexural test, the porous SiC/SiC composites showed pseudo-ductile behavior with sufficient strength even after heat treatment at high temperature in air. From these conclusions, it was proven that porous SiC/SiC composites were reliable material at severe environment such as high temperature in air, by introducing tape casting fabrication process that could produce reproducible materials with low cost and simple way. Therefore development of porous SiC/SiC composites for industrial application was

  7. In-beam γ-ray spectroscopy of the neutron rich 39Si

    International Nuclear Information System (INIS)

    Sohler, D.; Dombradi, Zs.; Achouri, N.L.; Angelique, J.C.; Bastin, B.; Azaiez, F.; Baiborodin, D.; Borcea, R.

    2009-01-01

    Complete text of publication follows. In order to clarify the role of proton excitations across the Z = 14 subshell closure in neutron-rich Si isotopes, we investigated the structure of the 14 39 Si 25 isotope, having three neutron-hole configurations with respect to an N = 28 core. The excited states of 39 Si were studied by in-beam γ-ray spectroscopy trough fragmentation of radioactive beams. The experiment was performed at the GANIL facility in France. The radioactive beams were produced by the fragmentation of the stable 48 Ca beam of 60 MeV/u energy and 4μA intensity on a 12 C target in the SISSI device. The cocktail beam produced was impinged onto a 9 Be target. The nuclei produced in the secondary fragmentation reaction were selected and unambiguously identified by the SPEG spectrometer. In the performed experiment the 39 Si nuclei were obtained via 1p, 1p1n, 2p1n and 2p2n knockout reactions from the 40,41 P and 42,43 S secondary beams. To measure the γ rays emitted from the excited states, the secondary target was surrounded by the 4π 'Chateau de Crystal' array consisting of 74 BaF 2 scintillators. The γ-ray spectra were generated by gating event-by-event on the incoming secondary beam particles and the ejectiles after the secondary target. For the γ rays emitted by the fast moving fragments accurate Doppler correction was performed. From the obtained γ spectra of 39 Si displayed in Figure 1, two strong γ transitions at 163 and 397 keV as well as weaker ones at 303, 657, 906, 1143 and 1551 keV have been identified. γγ coincidences were obtained in 39 Si after having added all data from the various reaction channels giving rise to 39 Si. Analysing these data the 163 keV transition was found to be in coincidence with the 657, 1143 and 1551 keV ones, but not with the 397 keV transition. The two lines of the 303+397 keV doublet are in mutual coincidence, and one or both of them are found in coincidence with the 906 keV transition.

  8. Status and prospects for SiC-SiC composite materials development for fusion applications

    International Nuclear Information System (INIS)

    Sharafat, S.; Jones, R.H.; Kohyama, A.; Fenici, P.

    1995-01-01

    Silicon carbide (SiC) composites are very attractive for fusion applications because of their low afterheat and low activation characteristics coupled with excellent high temperature properties. These composites are relatively new materials that will require material development as well as evaluation of hermiticity, thermal conductivity, radiation stability, high temperature strength, fatigue, thermal shock, and joining techniques. The radiation stability of SiC-SiC composites is a critical aspect of their application as fusion components and recent results will be reported. Many of the non-fusion specific issues are under evaluation by other ceramic composite development programs, such as the US national continuous fiber ceramic composites.The current development status of various SiC-SiC composites research and development efforts is given. Effect of neutron irradiation on the properties of SiC-SiC composite between 500 and 1200 C are reported. Novel high temperature properties specific to ceramic matrix composite (CMC) materials are discussed. The chemical stability of SiC is reviewed briefly. Ongoing research and development efforts for joining CMC materials including SiC-SiC composites are described. In conclusion, ongoing research and development efforts show extremely promising properties and behavior for SiC-SiC composites for fusion applications. (orig.)

  9. Linear dose dependence of ion beam mixing of metals on Si

    International Nuclear Information System (INIS)

    Poker, D.B.; Appleton, B.R.

    1985-01-01

    These experiments were conducted to determine the dose dependences of ion beam mixing of various metal-silicon couples. V/Si and Cr/Si were included because these couples were previously suspected of exhibiting a linear dose dependence. Pd/Si was chosen because it had been reported as exhibiting only the square root dependence. Samples were cut from wafers of (100) n-type Si. The samples were cleaned in organic solvents, etched in hydrofluoric acid, and rinsed with methanol before mounting in an oil-free vacuum system for thin-film deposition. Films of Au, V, Cr, or Pd were evaporated onto the Si samples with a nominal deposition rate of 10 A/s. The thicknesses were large compared with those usually used to measure ion beam mixing and were used to ensure that conditions of unlimited supply were met. Samples were mixed with Si ions ranging in energy from 300 to 375 keV, chosen to produce ion ranges that significantly exceeded the metal film depth. Si was used as the mixing ion to prevent impurity doping of the Si substrate and to exclude a background signal from the Rutherford backscattering (RBS) spectra. Samples were mixed at room temperature, with the exception of the Au/Si samples, which were mixed at liquid nitrogen temperature. The samples were alternately mixed and analyzed in situ without exposure to atmosphere between mixing doses. The compositional distributions after mixing were measured using RBS of 2.5-MeV 4 He atoms

  10. Energy variable monoenergetic positron beam study of oxygen atoms in Czochralski grown Si

    International Nuclear Information System (INIS)

    Tanigawa, S.; Wei, L.; Tabuki, Y.; Nagai, R.; Takeda, E.

    1992-01-01

    A monoenergetic positron beam has been used to investigate the state of interstitial oxygen in Czochralski-grown Si with the coverage of SiO 2 (100 nm) and poly-Si (200 nm)/SiO 2 (100 nm), respectively. It was found that (i) the growth of SiO 2 gives rise to a strong Doppler broadening of positron annihilation radiations in the bulk of Si, (ii) such a broadening can be recovered to the original level by annealing at 450degC, by the removal of overlayers using chemical etching and long-term aging at room temperature, (iii) the film stress over the CZ-grown Si is responsible for the rearrangement of oxygen atoms in S and (iv) only tensile stress gives rise to the clustering of oxygen atoms. The observed broadening was assigned to arise from the positron trapping by oxygen interstitial clusters. It was concluded that film stress is responsible for the rearrangement of oxygen atoms in CZ-grown Si. (author)

  11. Direct growth of Ge quantum dots on a graphene/SiO2/Si structure using ion beam sputtering deposition.

    Science.gov (United States)

    Zhang, Z; Wang, R F; Zhang, J; Li, H S; Zhang, J; Qiu, F; Yang, J; Wang, C; Yang, Y

    2016-07-29

    The growth of Ge quantum dots (QDs) using the ion beam sputtering deposition technique has been successfully conducted directly on single-layer graphene supported by SiO2/Si substrate. The results show that the morphology and size of Ge QDs on graphene can be modulated by tuning the Ge coverage. Charge transfer behavior, i.e. doping effect in graphene has been demonstrated at the interface of Ge/graphene. Compared with that of traditional Ge dots grown on Si substrate, the positions of both corresponding photoluminescence (PL) peaks of Ge QDs/graphene hybrid structure undergo a large red-shift, which can probably be attributed to the lack of atomic intermixing and the existence of surface states in this hybrid material. According to first-principles calculations, the Ge growth on the graphene should follow the so-called Volmer-Weber mode instead of the Stranski-Krastanow one which is observed generally in the traditional Ge QDs/Si system. The calculations also suggest that the interaction between Ge and graphene layer can be enhanced with the decrease of the Ge coverage. Our results may supply a prototype for fabricating novel optoelectronic devices based on a QDs/graphene hybrid nanostructure.

  12. Gamma and electron beam irradiation effects on SiR-EPDM blends

    Directory of Open Access Journals (Sweden)

    R. Deepalaxmi

    2014-07-01

    Full Text Available Ethylene Propylene Diene Monomer (EPDM is widely used as Cable Insulation Material (CIM due to its good mechanical strength. Silicone Rubber (SiR is used in high temperature environments due to its good di-electric properties/hydrophobicity. The blending of SiR-EPDM may result in the improvement in their specific properties. The SiR-EPDM blend of equal composition (50:50 was prepared. When such blends are used as Cable Insulation Materials (CIM, they should perform their safety functions throughout their installed life in Nuclear Power Plants (NPP. The CIM will be exposed to Gamma irradiation at the installed locations. The short time accelerated testing was carried out, in order to forecast long-term performance of CIM. Electron beam irradiation is widely used in cable manufacturing industries to improve the performance of the polymeric materials. In the current study, on the purpose to investigate the effect of gamma/electron beam irradiation on the 50–50 composition of SiR-EPDM blend, blend was exposed to 25 Mrad dose of gamma/electron beam irradiation. The electrical and mechanical parameters like Volume Resistivity (VRY, Surface Resistivity (SRY, Tensile Strength (TS, Elongation at Break (EB, Hardness (H of the virgin, gamma/electron beam irradiated blends were determined as per ASTM/IEC standards. The nature of degradation was investigated using Fourier Transform Infrared Spectroscopy (FTIR. To determine the elemental composition of the materials at the surface, Energy Dispersive X-ray Analysis (EDAX has been done. Scanning Electron Microscopy (SEM analysis has been done to study the morphological changes. The occurrence of cross-linking is found to be the mechanism for ageing in gamma/electron beam irradiated SiR-EPDM blends.

  13. Energy and time of flight measurements of REX-ISOLDE stable beams using Si detectors

    CERN Document Server

    Cantero, E D; Fraser, M A; Lanaia, D; Sosa, A; Voulot, D; Zocca, F

    2014-01-01

    In this paper we present energy and time spectroscopy measurements for the stable beams of REX-ISOLDE obtained using Si detectors. By using an alpha source as a calibration reference, the absolute energy E of stable beam particles (A/q = 4) was determined in spectroscopy mode in the energy range 1 MeV < E < 8 MeV (0.30 MeV/u < E/A < 1.87 MeV/u). The time of flight of the beam particles (2.18 MeV/u < E/A < 2.27 MeV/u) was determined by installing identical Si detectors in two diagnostic boxes separated by 7.7 m. The results obtained with these two techniques are compared with the values obtained by dipole scans using a bending magnet. The measurements took place between January and February of 2013.

  14. Development of SiC/SiC composite for fusion application

    International Nuclear Information System (INIS)

    Kohyama, A.; Katoh, Y.; Snead, L.L.; Jones, R.H.

    2001-01-01

    The recent efforts to develop SiC/SiC composite materials for fusion application under the collaboration with Japan and the USA are provided, where material performance with and without radiation damage has been greatly improved. One of the accomplishments is development of the high performance reaction sintering process. Mechanical and thermal conductivity are improved extensively by process modification and optimization with inexpensive fabrication process. The major efforts to make SiC matrix by CVI, PIP and RS methods are introduced together with the representing baseline properties. The resent results on mechanical properties of SiC/SiC under neutron irradiation are quite positive. The composites with new SiC fibers, Hi-Nicalon Type-S, did not exhibit mechanical property degradation up to 10 dpa. Based on the materials data recently obtained, a very preliminary design window is provided and the future prospects of SiC/SiC technology integration is provided. (author)

  15. InAs nanocrystals on SiO2/Si by molecular beam epitaxy for memory applications

    International Nuclear Information System (INIS)

    Hocevar, Moiera; Regreny, Philippe; Descamps, Armel; Albertini, David; Saint-Girons, Guillaume; Souifi, Abdelkader; Gendry, Michel; Patriarche, Gilles

    2007-01-01

    We studied a memory structure based on InAs nanocrystals grown by molecular beam epitaxy directly on thermal SiO 2 on silicon. Both nanocrystal diameter and density can be controlled by growth parameters. Transmission electron microscopy analysis shows high crystallinity and low size dispersion. In an electrical test structure with a 3.5 nm tunnel oxide, we observed that 80% of the initial injected electrons remain stored in the InAs nanocrystals after 3 months and that the retention time for electrons in InAs nanocrystals is four orders of magnitude higher than in silicon nanocrystals

  16. Defects in heavily phosphorus-doped Si epitaxial films probed by monoenergetic positron beams

    International Nuclear Information System (INIS)

    Uedono, Akira; Tanigawa, Shoichiro; Suzuki, Ryoichi; Ohgaki, Hideaki; Mikado, Tomohisa.

    1994-01-01

    Vacancy-type defects in heavily phosphorus-doped Si epitaxial films were probed by monoenergetic positron beams. Doppler broadening profiles of the annihilation radiation and lifetime spectra of positrons were measured for the epitaxial films grown on the Si substrates by plasma chemical vapor deposition. For the as-deposited film, divacancy-phosphorus complexes were found with high concentration. After 600degC annealing, vacancy clusters were formed near the Si/Si interface, while no drastic change in the depth distribution of the divacancy-phosphorus complexes was observed. By 900degC annealing, the vacancy clusters were annealed out; however, the average number of phosphorus atoms coupled with divacancies increased. The relationship between the vacancy-type defects probed by the positron annihilation technique and the carrier concentration was confirmed. (author)

  17. Defects in heavily phosphorus-doped Si epitaxial films probed by monoenergetic positron beams

    Energy Technology Data Exchange (ETDEWEB)

    Uedono, Akira; Tanigawa, Shoichiro [Tsukuba Univ., Ibaraki (Japan). Inst. of Materials Science; Suzuki, Ryoichi; Ohgaki, Hideaki; Mikado, Tomohisa

    1994-11-01

    Vacancy-type defects in heavily phosphorus-doped Si epitaxial films were probed by monoenergetic positron beams. Doppler broadening profiles of the annihilation radiation and lifetime spectra of positrons were measured for the epitaxial films grown on the Si substrates by plasma chemical vapor deposition. For the as-deposited film, divacancy-phosphorus complexes were found with high concentration. After 600degC annealing, vacancy clusters were formed near the Si/Si interface, while no drastic change in the depth distribution of the divacancy-phosphorus complexes was observed. By 900degC annealing, the vacancy clusters were annealed out; however, the average number of phosphorus atoms coupled with divacancies increased. The relationship between the vacancy-type defects probed by the positron annihilation technique and the carrier concentration was confirmed. (author).

  18. Interface plasmon-phonons modes in ion-beam synthesized Mg2Si nanolayers

    International Nuclear Information System (INIS)

    Baleva, M.; Zlateva, G.

    2009-01-01

    Raman scattering of samples, representing n- and p-type Si matrix with unburied Mg 2 Si nanolayers, formed by ion-beam synthesis, are studied. Despite the features in the Raman spectra attributed to the polariton modes with frequencies between those of the TO and LO phonons, additional features outside this interval are detected. The frequencies of these features are very sensitive to the plasma frequency, being different in the n- and p-type Si matrix and to the annealing time. The latter implies the generation of interface plasmonphonons modes. The frequencies of the interface plasmon-phonon modes are calculated and compared with the experimental results. The order of the carrier concentration in Mg 2 Si, the data of which are not available in the literature, is evaluated. (authors)

  19. Highly ordered nanopatterns on Ge and Si surfaces by ion beam sputtering

    International Nuclear Information System (INIS)

    Ziberi, B; Cornejo, M; Frost, F; Rauschenbach, B

    2009-01-01

    The bombardment of surfaces with low-energy ion beams leads to material erosion and can be accompanied by changes in the topography. Under certain conditions this surface erosion can result in well-ordered nanostructures. Here an overview of the pattern formation on Si and Ge surfaces under low-energy ion beam erosion at room temperature will be given. In particular, the formation of ripple and dot patterns, and the influence of different process parameters on their formation, ordering, shape and type will be discussed. Furthermore, the internal ion beam parameters inherent to broad beam ion sources are considered as an additional degree of freedom for controlling the pattern formation process. In this context: (i) formation of ripples at near-normal ion incidence, (ii) formation of dots at oblique ion incidence without sample rotation, (iii) transition between patterns, (iv) formation of ripples with different orientations and (v) long range ordered dot patterns will be presented and discussed.

  20. Ripple structures on surfaces and underlying crystalline layers in ion beam irradiated Si wafers

    Energy Technology Data Exchange (ETDEWEB)

    Grenzer, J.; Muecklich, A. [Forschungszentrum Rossendorf, Institut fuer Ionenstrahlphysik und Materialforschung, Dresden (Germany); Biermanns, A.; Grigorian, S.A.; Pietsch, U. [Institute of Physics, University of Siegen (Germany)

    2009-08-15

    We report on the formation of ion beam induced ripples in Si(001) wafers when bombarded with Ar+ ions at an energy of 60 keV. A set of samples varying incidence and azimuthal angles of the ion beam with respect to the crystalline surface orientation was studied by two complementary near surface sensitive techniques, namely atomic force microscopy and depth-resolved X-ray grazing incidence diffraction (GID). Additionally, cross-section TEM investigations were carried out. The ripple-like structures are formed at the sample surface as well as at the buried amorphous-crystalline interface. Best quality of the ripple pattern was found when the irradiating ion beam was aligned parallel to the (111) planes. The quality decreases rapidly if the direction of the ion beam deviates from (111). (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  1. Pulsed ion-beam induced nucleation and growth of Ge nanocrystals on SiO2

    International Nuclear Information System (INIS)

    Stepina, N. P.; Dvurechenskii, A. V.; Armbrister, V. A.; Kesler, V. G.; Novikov, P. L.; Gutakovskii, A. K.; Kirienko, V. V.; Smagina, Zh. V.; Groetzschel, R.

    2007-01-01

    Pulsed low-energy (200 eV) ion-beam induced nucleation during Ge deposition on thin SiO 2 film was used to form dense homogeneous arrays of Ge nanocrystals. The ion-beam action is shown to stimulate the nucleation of Ge nanocrystals when being applied after thin Ge layer deposition. Temperature and flux variation was used to optimize the nanocrystal size and array density required for memory device. Kinetic Monte Carlo simulation shows that ion impacts open an additional channel of atom displacement from a nanocrystal onto SiO 2 surface. This results both in a decrease in the average nanocrystal size and in an increase in nanocrystal density

  2. Defect layer in SiO2-Sic interface proved by a slow positron beam

    International Nuclear Information System (INIS)

    Maekawa, M.; Kawasuso, A.; Yoshikawa, M.; Miyashita, A.; Suzuki, R.; Ohdaira, T.

    2006-01-01

    The structure of the SiO 2 -4ph-SiC interface layer produced by dry oxidation has been studied by positron annihilation spectroscopy using slow positron beams. From Doppler broadening measurements, the interface layer was clearly distinguished from the SiO 2 and SiC layers and was observed to be defective. At the interface layer, a single long positron lifetime of 451 ps, which is close to the second lifetime in the SiO 2 layer, was obtained, thus suggesting that the structure of the interface layer resembles an amorphous SiO 2 network. A comparison was made between the obtained electron momentum distribution at the interface layer and the theoretical calculation. It was found that positrons annihilate with oxygen valence electrons. By annealing after the oxidation, the annihilation probability of the positrons with oxygen valence electrons and the number of interface traps decreased in the same temperature range, thus suggesting a correlation between interface traps and positron annihilation sites

  3. Resonant Raman scattering in ion-beam-synthesized Mg2Si in a silicon matrix

    International Nuclear Information System (INIS)

    Baleva, M.; Zlateva, G.; Atanassov, A.; Abrashev, M.; Goranova, E.

    2005-01-01

    Resonant Raman scattering by ion beam synthesized in silicon matrix Mg 2 Si phase is studied. The samples are prepared with the implantation of 24 Mg + ions with dose 4x10 17 cm -2 and with two different energies 40 and 60 keV into (100)Si substrates. The far infrared spectra are used as criteria for the formation of the Mg 2 Si phase. The Raman spectra are excited with different lines of Ar + laser, with energies of the lines lying in the interval from 2.40 to 2.75 eV. The resonant scattering can be investigated using these laser lines, as far as according to the Mg 2 Si band structure, there are direct gaps with energies in the same region. The energy dependences of the scattered intensities in the case of the scattering by the allowed F 2g and the forbidden LO-type modes are experimentally obtained and theoretically interpreted. On the base of the investigation energies of the interband transitions in the Mg 2 Si are determined. It is found also that the resonant Raman scattering appears to be a powerful tool for characterization of a material with inclusions in it. In the particular case it is concluded that the Mg 2 Si phase is present in the form of a surface layer in the sample, prepared with implantation energy 40 keV and as low-dimensional precipitates, embedded in the silicon matrix, in the sample, prepared with the higher implantation energy

  4. Single and multichannel scintillating fiber dosimeter for radiotherapic beams with SiPM readout

    Energy Technology Data Exchange (ETDEWEB)

    Berra, A., E-mail: alessandro.berra@gmail.it [Università degli Studi dell' Insubria e INFN sezione di Milano Bicocca (Italy); Ferri, A. [Fondazione Bruno Kessler, Centro per i Materiali e i Microsistemi (Italy); Novati, C. [Università degli Studi dell' Insubria e INFN sezione di Milano Bicocca (Italy); Ostinelli, A. [Ospedale Sant' Anna, Servizio di Fisica Sanitaria (Italy); Paternoster, G.; Piemonte, C. [Fondazione Bruno Kessler, Centro per i Materiali e i Microsistemi (Italy); Prest, M. [Università degli Studi dell' Insubria e INFN sezione di Milano Bicocca (Italy); Vallazza, E. [INFN Sezione di Trieste (Italy)

    2016-12-01

    The treatment of many neoplastic diseases requires the use of radiotherapy, which consists in the irradiation of the tumor, identified as the target volume, with ionizing radiations generated both by administered radiopharmaceuticals or by linear particle accelerators (LINACs). The radiotherapy beam delivered to the patient must be regularly checked to assure the best tumor control probability: this task is performed with dosimeters, i.e. devices able to provide a measurement of the dose deposited in their sensitive volume. This paper describes the development of two scintillator dosimeter prototypes for radiotherapic applications based on plastic scintillating fibers read out by high dynamic range Silicon PhotoMultipliers. The first dosimeter, consisting of a single-channel prototype with a pair of optical fibers, a scintillating and a white one, read out by two SiPMs, has been fully characterized and led to the development of a second multi-channel dosimeter based on an array of scintillating fibers: this device represents the first step towards the assembly of a “one-shot” device, capable to perform some of the daily quality controls in a few seconds. The dosimeters characterization was performed with a Varian Clinac iX linear accelerator at the Radiotherapy Department of the St. Anna Hospital in Como (IT).

  5. Optical and electrical properties of Si-nanocrystals ion beam synthesized in SiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Garrido, B. E-mail: blas@el.ub.es; Lopez, M.; Perez-Rodriguez, A.; Garcia, C.; Pellegrino, P.; Ferre, R.; Moreno, J.A.; Morante, J.R.; Bonafos, C.; Carrada, M.; Claverie, A.; Torre, J. de la; Souifi, A

    2004-02-01

    We review in this paper our recent results on the correlation between the structural and the optoelectronic properties of Si nano crystals (Si-nc) embedded in SiO{sub 2}. We describe as well the development of both materials and technology approaches that have allowed us to successfully produce efficient and reliable LEDs by using only CMOS processes. Si-nc were synthesised in SiO{sub 2} by ion implantation plus annealing and display average diameters from 2.5 to 6 nm, as measured by electron microscopy. By varying the annealing time in a large scale we have been able to track the nucleation, pure growth and Ostwald ripening stages of the nanocrystal population. The most efficient structures have Si-ncs with average size of 3 nm and densities of about 10{sup 19} cm{sup -3}. We have estimated band-gap energies, lifetimes (20-200 {mu}s) and absorption cross-sections (10{sup -15}-10{sup -16} cm{sup 2}) as a function of size and surface passivation. Based on these results, we propose a mechanism for exciton recombination based on the strong coupling of excitons with the heterointerfaces. From highly luminescent Si-nc, LEDs consisting of MOS capacitors were fabricated. Stable red electroluminescence has been obtained at room temperature and the I-V characteristics prove that the current is related to a pure tunnelling process. Fowler-Nordheim injection is not observed during light emission for electric fields below 5 MV/cm. Thus, hot carrier injection is avoided and efficient and reliable devices are obtained.

  6. Development of beam instruments at JAERI cyclotron facility

    Energy Technology Data Exchange (ETDEWEB)

    Okumura, Susumu; Fukuda, Mitsuhiro; Ishibori, Ikuo; Agematsu, Takashi; Yokota, Watalu; Nara, Takayuki; Nakamura, Yoshiteru; Arakawa, Kazuo [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1997-03-01

    A beam phase monitor and two kinds of fluence distribution monitors have been developed for measuring characteristics of cyclotron beams. The beam phase monitor provides a beam phase signal for tuning a beam chopping system and a beam phase selection system. A two-dimensional fluence distribution on a large area is measured with fluence distribution monitors. (author)

  7. Orientation-dependent ion beam sputtering at normal incidence conditions in FeSiAl alloy

    International Nuclear Information System (INIS)

    Batic, Barbara Setina; Jenko, Monika

    2010-01-01

    The authors have performed Ar+ broad ion beam sputtering of a polycrystalline Fe-Si-Al alloy at normal incidence at energies varying from 6 to 10 keV. Sputtering results in the formation of etch pits, which can be classified in three shapes: triangular, rectangular, and square. As each grain of individual orientation exhibits a certain type of pattern, the etch pits were correlated with the crystal orientations by electron backscattered diffraction technique.

  8. Electronic properties of single Ge/Si quantum dot grown by ion beam sputtering deposition.

    Science.gov (United States)

    Wang, C; Ke, S Y; Yang, J; Hu, W D; Qiu, F; Wang, R F; Yang, Y

    2015-03-13

    The dependence of the electronic properties of a single Ge/Si quantum dot (QD) grown by the ion-beam sputtering deposition technique on growth temperature and QD diameter is investigated by conductive atomic force microscopy (CAFM). The Si-Ge intermixing effect is demonstrated to be important for the current distribution of single QDs. The current staircase induced by the Coulomb blockade effect is observed at higher growth temperatures (>700 °C) due to the formation of an additional barrier between dislocated QDs and Si substrate for the resonant tunneling of holes. According to the proposed single-hole-tunneling model, the fact that the intermixing effect is observed to increase as the incoherent QD size decreases may explain the increase in the starting voltage of the current staircase and the decrease in the current step width.

  9. Thermoelectric Properties of Nanograined Si-Ge-Au Thin Films Grown by Molecular Beam Deposition

    Science.gov (United States)

    Nishino, Shunsuke; Ekino, Satoshi; Inukai, Manabu; Omprakash, Muthusamy; Adachi, Masahiro; Kiyama, Makoto; Yamamoto, Yoshiyuki; Takeuchi, Tsunehiro

    2018-06-01

    Conditions to achieve extremely large Seebeck coefficient and extremely small thermal conductivity in Si-Ge-Au thin films formed of nanosized grains precipitated in amorphous matrix have been investigated. We employed molecular beam deposition to prepare Si1- x Ge x Au y thin films on sapphire substrate. The deposited films were annealed under nitrogen gas atmosphere at 300°C to 500°C for 15 min to 30 min. Nanocrystals dispersed in amorphous matrix were clearly observed by transmission electron microscopy. We did not observe anomalously large Seebeck coefficient, but very low thermal conductivity of nearly 1.0 W K-1 m-1 was found at around 0.2 Si-Ge bulk material for which dimensionless figure of merit of ZT ≈ 1 was reported at high temperature.

  10. Development of spin polarized electron beam

    International Nuclear Information System (INIS)

    Nakanishi, Tsutomu

    2001-01-01

    Physical structure of the polarized electron beam production is explained in this paper. Nagoya University group has been improving the quality of beam. The present state of quality and the development objects are described. The new results of the polarized electron reported in 'RES-2000 Workshop' in October 2000, are introduced. The established ground of GaAs type polarized electron beam source, observation of the negative electron affinity (NEA) surface, some problems of NEA surface of high energy polarized electron beam such as the life, time response, the surface charge limited phenomena of NEA surface are explained. The interested reports in the RES-2000 Workshop consisted of observation by SPLEEM (Spin Low Energy Electron Microscope), Spin-STM and Spin-resolved Photoelectron Spectroscopy. To increase the performance of the polarized electron source, we will develop low emittance and large current. (S.Y.)

  11. Development and application of ion beam diagnostics

    International Nuclear Information System (INIS)

    Pfister, Jochen

    2010-01-01

    At GSI - Helmholtz Centre for Heavy Ion Research in Darmstadt/Germany the HITRAP project is in the commissioning phase. This world-wide unique facility consists of a linear decelerator for heavy, highly charged ions including atomic physics precision experiments. During commissioning of the cavities, transverse emittances were measured using the single-shot pepperpot method as well as the multi-gradient method. The extraction emittance of the experimental storage ring (ESR) was determined. Furthermore, the phase space distribution of an decelerated beam at an intermediate energy of 500keV/u was measured behind the IH-structure. New algorithms have been integrated into the analysis of digital images. The longitudinal bunch structure measurements of the ion beam at the entry point into the decelerator and the operation of the Double-drift Buncher is shown. The design, development and the first commissioning of a new single-shot pepperpot emittance meter for very low beam currents and beam energies in the order of some hundred nA is described, making it possible to measure the beam behind the deceleration cavities. In addition, transverse beam dynamics calculations were performed, which supported the hands-on commissioning of the accelerator. It is described how the entire beam line from the ESR to the radio-frequency quadrupole can be optimized using the new routine for transverse effects of the bunching and deceleration, which was successfully integrated into the software COSY Infinity. (orig.)

  12. Threshold stoichiometry for beam induced nitrogen depletion of SiN

    International Nuclear Information System (INIS)

    Timmers, H.; Weijers, T.D.M.; Elliman, R.G.; Uribasterra, J.; Whitlow, H.J.; Sarwe, E.-L.

    2002-01-01

    Measurements of the stoichiometry of silicon nitride films as a function of the number of incident ions using heavy ion elastic recoil detection (ERD) show that beam-induced nitrogen depletion depends on the projectile species, the beam energy, and the initial stoichiometry. A threshold stoichiometry exists in the range 1.3>N/Si≥1, below which the films are stable against nitrogen depletion. Above this threshold, depletion is essentially linear with incident fluence. The depletion rate correlates non-linearly with the electronic energy loss of the projectile ion in the film. Sufficiently long exposure of nitrogen-rich films renders the mechanism, which prevents depletion of nitrogen-poor films, ineffective. Compromising depth-resolution, nitrogen depletion from SiN films during ERD analysis can be reduced significantly by using projectile beams with low atomic numbers

  13. In-beam test of a DIRC Cherenkov radiator with SiPM

    International Nuclear Information System (INIS)

    Kroeck, B.; Hayrapetyan, A.; Foehl, K.; Merle, O.; Dueren, M.; Roy, B.J.; Peters, K.

    2009-01-01

    One of the crucial points for any high energy physics experiment is to obtain a good pion/kaon separation i.e. particle identification (PID). For particles in minimum ionising range, the conventional methods of PID using energy loss and time of flight become insufficient. In such a situation, the measurement of velocity of particles using Cherenkov radiation is an effective tool for PID in combination with momentum information from a tracking detector. The PANDA experiment at FAIR/ GSI plans to use a novel technique for PID with detection of internally reflected Cherenkov (DIRC) light. DIRC uses, in contrast to the conventional gas Cherenkov detectors, a solid radiator and total internal reflection to guide Cherenkov photons onto a detection plane where it will be detected by advanced photon counters. A SiPM is a very new generation photon counter that has several advantages over conventional PMTs. Several prototype Cherenkov detectors with different readout systems are being developed for R and D studies. One such prototype detector with Geiger-APD readout has been built at Giessen and was tested in-beam at GSI. The present report provides details of the very first test measurement

  14. Kinetics of Si and Ge nanowires growth through electron beam evaporation

    Directory of Open Access Journals (Sweden)

    Artoni Pietro

    2011-01-01

    Full Text Available Abstract Si and Ge have the same crystalline structure, and although Si-Au and Ge-Au binary alloys are thermodynamically similar (same phase diagram, with the eutectic temperature of about 360°C, in this study, it is proved that Si and Ge nanowires (NWs growth by electron beam evaporation occurs in very different temperature ranges and fluence regimes. In particular, it is demonstrated that Ge growth occurs just above the eutectic temperature, while Si NWs growth occurs at temperature higher than the eutectic temperature, at about 450°C. Moreover, Si NWs growth requires a higher evaporated fluence before the NWs become to be visible. These differences arise in the different kinetics behaviors of these systems. The authors investigate the microscopic growth mechanisms elucidating the contribution of the adatoms diffusion as a function of the evaporated atoms direct impingement, demonstrating that adatoms play a key role in physical vapor deposition (PVD NWs growth. The concept of incubation fluence, which is necessary for an interpretation of NWs growth in PVD growth conditions, is highlighted.

  15. Kinetics of Si and Ge nanowires growth through electron beam evaporation.

    Science.gov (United States)

    Artoni, Pietro; Pecora, Emanuele Francesco; Irrera, Alessia; Priolo, Francesco

    2011-02-21

    Si and Ge have the same crystalline structure, and although Si-Au and Ge-Au binary alloys are thermodynamically similar (same phase diagram, with the eutectic temperature of about 360°C), in this study, it is proved that Si and Ge nanowires (NWs) growth by electron beam evaporation occurs in very different temperature ranges and fluence regimes. In particular, it is demonstrated that Ge growth occurs just above the eutectic temperature, while Si NWs growth occurs at temperature higher than the eutectic temperature, at about 450°C. Moreover, Si NWs growth requires a higher evaporated fluence before the NWs become to be visible. These differences arise in the different kinetics behaviors of these systems. The authors investigate the microscopic growth mechanisms elucidating the contribution of the adatoms diffusion as a function of the evaporated atoms direct impingement, demonstrating that adatoms play a key role in physical vapor deposition (PVD) NWs growth. The concept of incubation fluence, which is necessary for an interpretation of NWs growth in PVD growth conditions, is highlighted.

  16. Fabrication of highly oriented β-FeSi2 by ion beam sputter deposition

    International Nuclear Information System (INIS)

    Nakanoya, Takamitsu; Sasase, Masato; Yamamoto, Hiroyuki; Saito, Takeru; Hojou, Kiichi

    2002-01-01

    We have prepared the 'environmentally friendly' semiconductor, β-FeSi 2 thin films by ion beam sputter deposition method. The temperature of Si (100) substrate during the deposition and total amount of deposited Fe have been changed in order to find the optimum condition of the film formation. The crystallinity and surface morphology of the formed silicides were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. It is understood that the domain of the epitaxially grown β-FeSi 2 increases with the substrate temperature up to 700degC at the fixed amount of deposited Fe (33 nm) by XRD spectra. On the other hand, α-FeSi 2 is appeared and increased with the temperature above 700degC. Granulation of the surface is also observed by SEM images at this temperature region. At the fixed temperature condition (700degC), formation of α phase, which is obtained at the higher temperature compared with β phase, is observed for the fewer deposited samples. These results suggest the possibility of the epitaxially grown β-FeSi 2 formation at the lower (< 700degC) temperature region. (author)

  17. Role of yttria-stabilized zirconia produced by ion-beam-assisted deposition on the properties of RuO2 on SiO2/Si

    International Nuclear Information System (INIS)

    Jia, Q.X.; Arendt, P.; Groves, J.R.; Fan, Y.; Roper, J.M.; Foltyn, S.R.

    1998-01-01

    Highly conductive biaxially textured RuO 2 thin films were deposited on technically important SiO 2 /Si substrates by pulsed laser deposition, where yttria-stabilized zirconia (YSZ) produced by ion-beam-assisted-deposition (IBAD) was used as a template to enhance the biaxial texture of RuO 2 on SiO 2 /Si. The biaxially oriented RuO 2 had a room-temperature resistivity of 37 μΩ-cm and residual resistivity ratio above 2. We then deposited Ba 0.5 Sr 0.5 TiO 3 thin films on RuO 2 /IBAD-YSZ/SiO 2 /Si. The Ba 0.5 Sr 0.5 TiO 3 had a pure (111) orientation normal to the substrate surface and a dielectric constant above 360 at 100 kHz. copyright 1998 Materials Research Society

  18. Beam developments for the Harwell microprobe system

    International Nuclear Information System (INIS)

    Read, P.M.; Cookson, J.A.; Alton, G.D.

    1986-01-01

    A consequence of the rapid development of micron and submicron size electronic devices is the diminished applicability of high energy ion microprobes with their present resolution limitations to the study of such components. Although submicron beams have been reported the available beam current is barely sufficiently for PIXE and is not adequate for RBS. This lack of lateral resolution is due to low beam brightness at the microprobe object and aberrations in the focusing elements. As part of a program to address these problems the Harwell microprobe lens has been relocated on a new 5 MV Laddertron accelerator. The increased brightness and improved stability of this facility has so far led to a reduction in beam size from 3 x 3 μm 2 to about 2 x 2 μm 2 . The feasibility of using a liquid metal ion source has been examined with a view to achieving more substantial increases in brightness. While such sources have brightness approximately 10 5 times greater than conventional gaseous sources the highly divergent nature of the beam presents problems for the beam transport system. The use of a liquid metal source on the accelerator has been successfully demonstrated but it indicates the need for a special low aberration injection lens if brightness is to be maintained

  19. Intense diagnostic neutral beam development for ITER

    International Nuclear Information System (INIS)

    Rej, D.J.; Henins, I.; Fonck, R.J.; Kim, Y.J.

    1992-01-01

    For the next-generation, burning tokamak plasmas such as ITER, diagnostic neutral beams and beam spectroscopy will continue to be used to determine a variety of plasma parameters such as ion temperature, rotation, fluctuations, impurity content, current density profile, and confined alpha particle density and energy distribution. Present-day low-current, long-pulse beam technology will be unable to provide the required signal intensities because of higher beam attenuation and background bremsstrahlung radiation in these larger, higher-density plasmas. To address this problem, we are developing a short-pulse, intense diagnostic neutral beam. Protons or deuterons are accelerated using magnetic-insulated ion-diode technology, and neutralized in a transient gas cell. A prototype 25-kA, 100-kV, 1-μs accelerator is under construction at Los Alamos. Initial experiments will focus on ITER-related issues of beam energy distribution, current density, pulse length, divergence, propagation, impurity content, reproducibility, and maintenance

  20. Tuning of Schottky barrier height of Al/n-Si by electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Vali, Indudhar Panduranga [Manipal Institute of Technology, Manipal University, Manipal 576104 (India); Shetty, Pramoda Kumara, E-mail: pramod.shetty@manipal.edu [Manipal Institute of Technology, Manipal University, Manipal 576104 (India); Mahesha, M.G. [Manipal Institute of Technology, Manipal University, Manipal 576104 (India); Petwal, V.C.; Dwivedi, Jishnu [Raja Ramanna Centre for Advanced Technology, Department of Atomic Energy, Government of India, Indore 452012 (India); Choudhary, R.J. [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452017 (India)

    2017-06-15

    Highlights: • Tuning of Schottky barrier height has been achieved by electron beam irradiation at different doses on n-Si wafer prior to the fabrication of Schottky contact. • The XPS analyses have shown irradiation induced defects and the formation of several localized chemical states in Si/SiOx interface that influences the Schottky barrier height. • High ideality factor indicates metal-insulator-semiconductor configuration of the Schottky diode and the inhomogeneous nature of the Schottky barrier height. • The modifications in I–V characteristics have been observed as a function of electron dose. This is caused due to changes in the Schottky diode parameters and different transport mechanisms. - Abstract: The effect of electron beam irradiation (EBI) on Al/n-Si Schottky diode has been studied by I–V characterization at room temperature. The behavior of the metal-semiconductor (MS) interface is analyzed by means of variations in the MS contact parameters such as, Schottky barrier height (Φ{sub B}), ideality factor (n) and series resistance (R{sub s}). These parameters were found to depend on the EBI dose having a fixed incident beam of energy 7.5 MeV. At different doses (500, 1000, 1500 kGy) of EBI, the Schottky contacts were prepared and extracted their contact parameters by applying thermionic emission and Cheung models. Remarkably, the tuning of Φ{sub B} was observed as a function of EBI dose. The improved n with increased Φ{sub B} is seen for all the EBI doses. As a consequence of which the thermionic emission is more favored. However, the competing transport mechanisms such as space charge limited emission, tunneling and tunneling through the trap states were ascribed due to n > 1. The analysis of XPS spectra have shown the presence of native oxide and increased radiation induced defect states. The thickness variation in the MS interface contributing to Schottky contact behavior is discussed. This study explains a new technique to tune

  1. Raman investigation of GaP–Si interfaces grown by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Bondi, A.; Cornet, C.; Boyer, S.; Nguyen Thanh, T.; Létoublon, A.; Pedesseau, L.; Durand, O. [Université Européenne de Bretagne, INSA, FOTON, UMR CNRS 6082, 20 Avenue des Buttes de Coësmes, F-35708 Rennes (France); Moreac, A. [Institut de Physique de Rennes, UMR-CNRS n°6251, Université Rennes1, Campus de Beaulieu — 35042 Rennes cedex (France); Ponchet, A. [CEMES, UPR CNRS 8011, F-31055 Toulouse (France); Le Corre, A. [Université Européenne de Bretagne, INSA, FOTON, UMR CNRS 6082, 20 Avenue des Buttes de Coësmes, F-35708 Rennes (France); Even, J., E-mail: jacky.even@insa.rennes.fr [Université Européenne de Bretagne, INSA, FOTON, UMR CNRS 6082, 20 Avenue des Buttes de Coësmes, F-35708 Rennes (France)

    2013-08-31

    Raman spectroscopy was used to investigate the residual strain in thin GaP layers deposited on Si substrates by molecular beam epitaxy. Different growth conditions were used to obtain a clean GaP–Si interface, including migration enhanced epitaxy. The strain induced Raman shifts of the longitudinal and the transverse optical GaP lattice modes were analyzed. The effects of crystalline defects are discussed, supported by high resolution transmission electron microscopy and X-ray scattering studies. Finally, Raman Spectroscopy reveals the presence of disorder (or surface)-activated optical phonons. This result is discussed in the light of surface morphology analyses. - Highlights: ► GaP thin layers grown by molecular beam epitaxy on Si substrates. ► Strain-induced Raman shifts of the optical GaP modes are analyzed. ► Simulation of optical GaP modes by density functional perturbation theory. ► Comparison with X-ray diffraction and electron and scanning probe microscopy data.

  2. Development of KSTAR Neutral Beam Heating System

    Energy Technology Data Exchange (ETDEWEB)

    Oh, B. H.; Song, W. S.; Yoon, B. J. (and others)

    2007-10-15

    The prototype components of a neutral beam injection (NBI) system have been developed for the KSTAR, and a capability of the manufactured components has been tested. High power ion source, acceleration power supply, other ion source power supplies, neutralizer, bending magnet for ion beam separation, calorimeter, and cryo-sorption pump have been developed by using the domestic technologies and tested for a neutral beam injection of 8 MW per beamline with a pulse duration of 300 seconds. The developed components have been continuously upgraded to achieve the design requirements. The development technology of high power and long pulse neutral beam injection system has been proved with the achievement of 5.2 MW output for a short pulse length and 1.6 MW output for a pulse length of 300 seconds. Using these development technologies, the domestic NB technology has been stabilized under the development of high power ion source, NB beamline components, high voltage and current power supplies, NB diagnostics, NB system operation and control.

  3. SiO2 Antireflection Coatings Fabricated by Electron-Beam Evaporation for Black Monocrystalline Silicon Solar Cells

    Directory of Open Access Journals (Sweden)

    Minghua Li

    2014-01-01

    Full Text Available In this work we prepared double-layer antireflection coatings (DARC by using the SiO2/SiNx:H heterostructure design. SiO2 thin films were deposited by electron-beam evaporation on the conventional solar cell with SiNx:H single-layer antireflection coatings (SARC, while to avoid the coverage of SiO2 on the front side busbars, a steel mask was utilized as the shelter. The thickness of the SiNx:H as bottom layer was fixed at 80 nm, and the varied thicknesses of the SiO2 as top layer were 105 nm and 122 nm. The results show that the SiO2/SiNx:H DARC have a much lower reflectance and higher external quantum efficiency (EQE in short wavelengths compared with the SiNx:H SARC. A higher energy conversion efficiency of 17.80% was obtained for solar cells with SiO2 (105 nm/SiNx:H (80 nm DARC, an absolute conversion efficiency increase of 0.32% compared with the conventional single SiNx:H-coated cells.

  4. Characterization of the crystalline quality of β-SiC formed by ion beam synthesis

    International Nuclear Information System (INIS)

    Intarasiri, S.; Hallen, A.; Kamwanna, T.; Yu, L.D.; Possnert, G.; Singkarat, S.

    2006-01-01

    The ion beam synthesis (IBS) technique is applied to form crystalline silicon carbide (SiC) for future optoelectronics applications. Carbon ions at 80 and 40 keV were implanted into (1 0 0) high-purity p-type silicon wafers at room temperature and 400 deg. C, respectively, to doses in excess of 10 17 ions/cm 2 . Subsequent thermal annealing of the implanted samples was performed in a vacuum furnace at temperatures of 800, 900 and 1000 deg. C, respectively. Elastic recoil detection analysis was used to investigate depth distributions of the implanted ions and infrared transmittance (IR) measurement was used to characterize formation of SiC in the implanted Si substrate. Complementary to IR, Raman scattering measurements were also carried out. Levels of the residual damage distribution of the samples annealed at different temperatures were compared with that of the as-implanted one by Rutherford backscattering spectrometry (RBS) in the channeling mode. The results show that C-ion implantation at the elevated temperature, followed by high-temperature annealing, enhances the synthesis of crystalline SiC

  5. Ellipsometric study of GaN/AIN/Si(111) heterostructures grown by molecular beam epitaxy

    International Nuclear Information System (INIS)

    Nabi, M. A. U.; Ashfaq, A.; Arshad, M. I.; Ali, A.; Mahmood, K.; Hasan, M. A.; Asghar, M.

    2013-01-01

    GaN and related structures attracted a great interest in the recent years for electronic and optoelectronic applications due to their promising properties. GaN is grown popularly on foreign substrates like sapphire and SiC. However, silicon due to its favourable properties attended the great attention of material scientists and researchers to utilize as substrate for heteroepitaxy of GaN based structures and devices. Silicon substrates are low cost, available in large diameters and have well characterized thermal and electrical properties. In this study, GaN/AlN/Si(111) heterostructures were grown by molecular beam epitaxy. We performed x-ray diffraction spectroscopy and spectroscopic ellipsometry on these samples to study their structural and optical properties. XRD measurements performed on these samples revealed the presence of high quality GaN films as well as the presence of AlN buffer layer with the following miller indices: GaN (002), GaN (004), GaN (006) and GaN (110) along with Si peak of phase (111). The ellipsometric data obtained were used to characterize the GaN/Si samples as a function of film thickness. Refractive index, extinction coefficient and dielectric constant were calculated by the measured data. (author)

  6. Si Incorporation in InP Nanowires Grown by Au-Assisted Molecular Beam Epitaxy

    Directory of Open Access Journals (Sweden)

    Lorenzo Rigutti

    2009-01-01

    Full Text Available We report on the growth, structural characterization, and conductivity studies of Si-doped InP nanowires grown by Au-assisted molecular beam epitaxy. It is shown that Si doping reduces the mean diffusion length of adatoms on the lateral nanowire surface and consequently reduces the nanowire growth rate and promotes lateral growth. A resistivity as low as 5.1±0.3×10−5 Ω⋅cm is measured for highly doped nanowires. Two dopant incorporation mechanisms are discussed: incorporation via catalyst particle and direct incorporation on the nanowire sidewalls. The first mechanism is shown to be less efficient than the second one, resulting in inhomogeneous radial dopant distribution.

  7. Development of electron beam deflection circuit

    International Nuclear Information System (INIS)

    Leo Kwee Wah; Lojius Lombigit; Abu Bakar Ghazali; Azaman

    2007-01-01

    This paper describes a development of a power supply circuit to deflect and move the electron beam across the window of the Baby electron beam machine. It comprises a discussion of circuit design, its assembly and the test results. A variety of input and output conditions have been tested and it was found that the design is capable to supply 1.0 A with 50Hz on X-axis coil and 0.4A with 500Hz on Y-axis coil. (Author)

  8. Neutral-beam-heating applications and development

    International Nuclear Information System (INIS)

    Menon, M.M.

    1981-01-01

    The technique of heating the plasma in magnetically confined fusion devices by the injection of intense beams of neutral atoms is described. The basic principles governing the physics of neutral beam heating and considerations involved in determining the injection energy, power, and pulse length required for a fusion reactor are discussed. The pertinent experimental results from various fusion devices are surveyed to illustrate the efficacy of this technique. The second part of the paper is devoted to the technology of producing the neutral beams. A state-of-the-art account o the development of neutral injectors is presented, and the prospects for utilizing neutral injection to heat the plasma in a fusion reactor are examined

  9. Development in distributed beam-view

    International Nuclear Information System (INIS)

    Bhole, R.B.; Pal, Satbajit; Dasgupta, S.

    2003-01-01

    A computerized distributed beam-viewer has been developed using PC-add on image digitizer card plugged into a Pentium PC running Windows NT. Image Acquisition card (IMAQ-1408) from National Instruments is driven to digitise inputs from CCD cameras placed along the beam transport lines. The multiple clients situated across a switched Ethernet LAN, collects the data and displays beam-views on a desirable Window size. Only one privilege client at the control room has the selection facility of the channel (camera), whereas image display processing and storing facility are provided at all other clients end. The client server S/W written on Window SDK is implemented using Window Socket ver 2.0 library functions. (author)

  10. Annealing of TiO2 Films Deposited on Si by Irradiating Nitrogen Ion Beams

    International Nuclear Information System (INIS)

    Yokota, Katsuhiro; Yano, Yoshinori; Miyashita, Fumiyoshi

    2006-01-01

    Thin TiO2 films were deposited on Si at a temperature of 600 deg. C by an ion beam assisted deposition (IBAD) method. The TiO2 films were annealed for 30 min in Ar at temperatures below 700 deg. C. The as-deposited TiO2 films had high permittivities such 200 εo and consisted of crystallites that were not preferentially oriented to the c-axis but had an expanded c-axis. On the annealed TiO2 films, permittivities became lower with increasing annealing temperature, and crystallites were oriented preferentially to the (110) plane

  11. Multi-beam injector development at LBL

    International Nuclear Information System (INIS)

    Rutkowski, H.L.; Faltens, A.; Brodzik, D.A.; Johnson, R.M.; Pike, C.D.; Vanecek, D.L.; Humphries, S. Jr.; Meyer, E.A.; Hewett, D.W.

    1990-06-01

    LBL is developing a multi-beam injector that will be used for scaled accelerator experiments related to Heavy Ion Fusion. The device will produce sixteen 0.5 Amp beams of C+ at 2 MeV energy. The carbon arc source has been developed to the point where the emittance is within a factor of four of the design target. Modelling of the source behavior to find ways to reduce the emittance is discussed. Source lifetime and reliability is also of paramount importance to us and data regarding the lifetime and failure modes of different source configurations is discussed. One half of the accelerating column has been constructed and tested at high voltage. One beam experiments in this half column are underway. The second half of the column is being built and the transition 2 MV experiments should begin soon. In addition to beam and source performance we also discuss the controls for the injector and the electronics associated with the source and current injection. 3 refs., 2 figs

  12. Electrical characterization of defects introduced in n-Si during electron beam deposition of Pt

    Energy Technology Data Exchange (ETDEWEB)

    Auret, F.D.; Coelho, S.M.M.; Nel, J.M.; Meyer, W.E. [Physics Department, University of Pretoria, Pretoria (South Africa)

    2012-10-15

    We have used deep level transient spectroscopy (DLTS) and high resolution DLTS to characterize the defects introduced in epitaxially grown n-type, P-doped, Si during electron beam deposition (EBD) of Pt for Schottky contact formation. The identity of some of these defects could be established by comparing their properties to those of well-known defects introduced by high energy electron irradiation of the same material. The most prominent EBD-induced defects thus identified were the E-center (VP center), the A-center (VO center), interstitial carbon (C{sub i}), and the interstitial carbon-substitutional carbon (C{sub i}C{sub s}) pair. EBD also introduced some defects that were not observed after high energy electron irradiation. DLTS depth profiling revealed that the main defects, VO and VP, could be detected up to 0.5 {mu}m below the metal-Si interface. Shielding the sample from particles originating in the region of the electron beam significantly reduced defect introduction and resulted in Schottky contacts with improved rectification properties. Finally, we have found that exposing the sample to EBD conditions, without actually depositing metal, introduced a different set of electron traps, not introduced by the EBD process. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Development of Readout Interconnections for the Si-W Calorimeter of SiD

    Energy Technology Data Exchange (ETDEWEB)

    Woods, M.; Fields, R.G.; Holbrook, B.; Lander, R.L.; Moskaleva, A.; Neher, C.; Pasner, J.; Tripathi, M.; /UC, Davis; Brau, J.E.; Frey, R.E.; Strom, D.; /Oregon U.; Breidenbach, M.; Freytag, D.; Haller, G.; Herbst, R.; Nelson, T.; /SLAC; Schier, S.; Schumm, B.; /UC, Santa Cruz

    2012-09-14

    The SiD collaboration is developing a Si-W sampling electromagnetic calorimeter, with anticipated application for the International Linear Collider. Assembling the modules for such a detector will involve special bonding technologies for the interconnections, especially for attaching a silicon detector wafer to a flex cable readout bus. We review the interconnect technologies involved, including oxidation removal processes, pad surface preparation, solder ball selection and placement, and bond quality assurance. Our results show that solder ball bonding is a promising technique for the Si-W ECAL, and unresolved issues are being addressed.

  14. Advanced Environmental Barrier Coating Development for SiC/SiC Ceramic Matrix Composites: NASA's Perspectives

    Science.gov (United States)

    Zhu, Dongming

    2016-01-01

    This presentation reviews NASA environmental barrier coating (EBC) system development programs and the coating materials evolutions for protecting the SiC/SiC Ceramic Matrix Composites in order to meet the next generation engine performance requirements. The presentation focuses on several generations of NASA EBC systems, EBC-CMC component system technologies for SiC/SiC ceramic matrix composite combustors and turbine airfoils, highlighting the temperature capability and durability improvements in simulated engine high heat flux, high pressure, high velocity, and with mechanical creep and fatigue loading conditions. The current EBC development emphasis is placed on advanced NASA 2700F candidate environmental barrier coating systems for SiC/SiC CMCs, their performance benefits and design limitations in long-term operation and combustion environments. Major technical barriers in developing environmental barrier coating systems, the coating integrations with next generation CMCs having the improved environmental stability, erosion-impact resistance, and long-term fatigue-environment system durability performance are described. The research and development opportunities for advanced turbine airfoil environmental barrier coating systems by utilizing improved compositions, state-of-the-art processing methods, and simulated environment testing and durability modeling are discussed.

  15. The role of Si as surfactant and donor in molecular-beam epitaxy of AlN

    International Nuclear Information System (INIS)

    Lebedev, V.; Morales, F.M.; Romanus, H.; Krischok, S.; Ecke, G.; Cimalla, V.; Himmerlich, M.; Stauden, T.; Cengher, D.; Ambacher, O.

    2005-01-01

    The growth of Si-doped AlN(0001) thin films on Al 2 O 3 (0001) substrates by plasma-induced molecular-beam epitaxy is reported. We have found that Si positively affects the epitaxy being an effective surfactant for AlN growth with a remarkable impact on the crystal quality. It was proven that the characteristic surface reconstruction sequences frequently related to the Al adatoms are obviously Si induced on AlN(0001) surfaces. It was also observed that heavy doping conditions result in volume segregation of Si on the threading dislocation network and in the formation of an amorphous (AlO)(SiO)N cap layer caused by surface oxidation of the accumulated Al and segregated Si. The electron affinity was measured to be smaller than 0.5 eV on the clean AlN surface after removing of the cap layer using Ar + sputtering

  16. Beam Delivery Simulation: BDSIM - Development & Optimization

    CERN Document Server

    Nevay, Laurence James; Garcia-Morales, H; Gibson, S M; Kwee-Hinzmann, R; Snuverink, J; Deacon, L C

    2014-01-01

    Beam Delivery Simulation (BDSIM) is a Geant4 and C++ based particle tracking code that seamlessly tracks particles through accelerators and detectors, including the full range of particle interaction physics processes from Geant4. BDSIM has been successfully used to model beam loss and background conditions for many current and future linear accelerators such as the Accelerator Test Facility 2 (ATF2) and the International Linear Collider (ILC). Current developments extend its application for use with storage rings, in particular for the Large Hadron Collider (LHC) and the High Luminosity upgrade project (HL-LHC). This paper presents the latest results from using BDSIM to model the LHC as well as the developments underway to improve performance.

  17. On nonlinear development of beam instability

    International Nuclear Information System (INIS)

    Popel', S.I.; Tsytovich, V.N.

    1990-01-01

    Radiation-resonance interactions are taken into account in the problem of dynamics of an electron beam inb plasma. The beam characteristics to be taken into account are determined. Stabilization conditions for beam instability are established

  18. A study of vacancy-type defects in B+-implanted SiO2/Si by a slow positron beam

    International Nuclear Information System (INIS)

    Uedono, Akira; Tanigawa, Shoichiro; Sugiura, Jun; Ogasawara, Makoto.

    1989-01-01

    Variable-energy (0∼30 keV) positron beam studies have been carried out on 80 keV B + -implanted SiO 2 (43 nm)/Si specimens. Doppler broadening profiles of the positron annihilation as a function of the incident positron energy were shown to be quite sensitive for the detection of vacancy-type defects introduced by B + -implantation. The average depth of the defected regions was found to shift towards the surface of the specimen with increasing the dose of B + ions. This effect is attributed to the accumulation of vacancy-type defects at the SiO 2 /Si interface. Dominant defect species were identified as vacancy clusters by their annealing stage. (author)

  19. Development of beam diagnostic devices for characterizing electron guns

    International Nuclear Information System (INIS)

    Bhattacharjee, D.; Tiwari, R.; Jayaprakash, D.; Mishra, R.L.; Sarukte, H.; Waghmare, A.; Thakur, N.; Dixit, K.P.

    2015-01-01

    The electron guns for the DC accelerators and RF Linacs are designed and developed at EBC/APPD/BARC, Kharghar. These electron guns need to be characterized for its design and performance. Two test benches were developed for characterizing the electron guns. Various beam diagnostic devices for measuring beam currents and beam sizes were developed. Conical faraday cup, segmented faraday cup, slit scanning bellows movement arrangement, multi-plate beam size measurement setup, multi- wire beam size measurement setup, Aluminum foil puncture assembly etc. were developed and used. The paper presents the in-house development of various beam diagnostics for characterizing electron guns and their use. (author)

  20. Dual deflectable beam strip engine development.

    Science.gov (United States)

    Dulgeroff, C. R.; Zuccaro, D. E.; Kami, S.; Schnelker, D. E.; Ward, J. W.

    1972-01-01

    This paper describes a dual beam thruster that has been designed, constructed, and tested. The system is suitable for two-axes attitude control and is comprised of two orthogonal strips, each capable of producing 0.30 mlb thrust and beam deflections of more than plus or minus 20 deg. The nominal specific impulse for the thruster is 5000 sec, and the thrust level from each strip can be varied from 0 to 100%. Neutralizer filaments that were developed and life tested over 2000 hours producing more than 40 mA of electron emission per watt of input power are also discussed. The system power required for clean ionizers is approximately 200 W.

  1. Room-Temperature Growth of SiC Thin Films by Dual-Ion-Beam Sputtering Deposition

    Directory of Open Access Journals (Sweden)

    C. G. Jin

    2008-01-01

    Full Text Available Silicon carbide (SiC films were prepared by single and dual-ion-beamsputtering deposition at room temperature. An assisted Ar+ ion beam (ion energy Ei = 150 eV was directed to bombard the substrate surface to be helpful for forming SiC films. The microstructure and optical properties of nonirradicated and assisted ion-beam irradicated films have been characterized by transmission electron microscopy (TEM, scanning electron microscopy (SEM, Fourier transform infrared spectroscopy (FTIR, and Raman spectra. TEM result shows that the films are amorphous. The films exposed to a low-energy assisted ion-beam irradicated during sputtering from a-SiC target have exhibited smoother and compacter surface topography than which deposited with nonirradicated. The ion-beam irradicated improves the adhesion between film and substrate and releases the stress between film and substrate. With assisted ion-beam irradicated, the density of the Si–C bond in the film has increased. At the same time, the excess C atoms or the size of the sp2 bonded clusters reduces, and the a-Si phase decreases. These results indicate that the composition of the film is mainly Si–C bond.

  2. Degradation effects and Si-depth profiling in photoresists using ion beam analysis

    NARCIS (Netherlands)

    IJzendoorn, van L.J.; Schellekens, J.P.W.

    1989-01-01

    The reaction of silicon-containing vapour with a photoresist layer, as used in dry developable lithographic processes, was studied with Rutherford backscattering spectrometry (RBS). Degradation of the polymer layer was observed, but the total amount of incorporated Si was found to be constant during

  3. Development of beam utilization/application technology

    Energy Technology Data Exchange (ETDEWEB)

    Choi, B H; Kim, Y K; Song, T Y [and others

    1999-05-01

    High power proton accelerator is considered as one of national fundamental research facilities and a key to advanced nuclear technology development, having been widely used in an un detachable relationship with nuclear research in advanced countries. The high power proton accelerator will be installed in several phases as an up front facility of the nuclear waste transmutation system. It is expected that a common understanding and a general agreement over proper utilization of the accelerator should be deduced and that a user program for beam utilization and application should be firmly established in time for the completion of each phase of the accelerator. This high power proton accelerator will consist of several component accelerators and, from up front, accelerators such as injector, RFQ, CCDTL, etc. will be installed in sequence and deliver respectively at each stage beams of 3MeV, 20MeV, 100Mev, etc. to be variously utilized forindustries, defence industry, medical treatment, environmental protection and basic science research. In order for the accelerator to be fully utilized as a national fundamental research facility beyond nuclear field, it is necessary to formulate a proceeding plan of the user program for the accelerator and to cultivate industrial utilization/application studies of proton beams accelerated by injector or RFQ of the accelerator. (author). 38 refs., 84 tabs., 39 figs.

  4. Development of beam utilization/application technology

    International Nuclear Information System (INIS)

    Choi, B. H.; Kim, Y.K.; Song, T.Y.

    1999-05-01

    High power proton accelerator is considered as one of national fundamental research facilities and a key to advanced nuclear technology development, having been widely used in an un detachable relationship with nuclear research in advanced countries. The high power proton accelerator will be installed in several phases as an up front facility of the nuclear waste transmutation system. It is expected that a common understanding and a general agreement over proper utilization of the accelerator should be deduced and that a user program for beam utilization and application should be firmly established in time for the completion of each phase of the accelerator. This high power proton accelerator will consist of several component accelerators and, from up front, accelerators such as injector, RFQ, CCDTL, etc. will be installed in sequence and deliver respectively at each stage beams of 3MeV, 20MeV, 100Mev, etc. to be variously utilized for industries, defence industry, medical treatment, environmental protection and basic science research. In order for the accelerator to be fully utilized as a national fundamental research facility beyond nuclear field, it is necessary to formulate a proceeding plan of the user program for the accelerator and to cultivate industrial utilization/application studies of proton beams accelerated by injector or RFQ of the accelerator. (author). 38 refs., 84 tabs., 39 figs

  5. Self-organization of nanocluster δ-layers at ion-beam-mixed Si-SiO2 interfaces

    International Nuclear Information System (INIS)

    Roentzsch, L.

    2003-11-01

    This diploma thesis presents experimental evidence of a theoretical concept which predicts the self-organization of δ-layers of silicon nanoclusters in the buried oxide of a MOS-like structure. This approach of ''bottom-up'' structuring might be of eminent importance in view of future semiconductor memory devices. Unconventionally, a 15 nm thin SiO 2 layer, which is enclosed by a 50 nm poly-Si capping layer and the Si substrate, is irradiated with Si + ions. Ion impact drives the system to a state far from thermodynamic equilibrium, i.e. the local composition of the target is modified to a degree unattainable in common processes. A region of SiO x (x 2 matrix at a distance of ∼3 nm from the Si substrate. The physical mechanisms of ion mixing of the two Si-SiO 2 interfaces and subsequent phase separation, which result in the desired sample structure, are elucidated from the viewpoint of computer simulations. In addition, experimental evidence is presented based on various methods, including TEM, RBS, and SIMS. A novel method of Si nanocluster decoration is of particular importance which applies Ge as contrast enhancing element in TEM studies of tiny Si nanoclusters. (orig.)

  6. Inhomogeneous Si-doping of gold-seeded InAs nanowires grown by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Rolland, Chloe; Coinon, Christophe; Wallart, Xavier; Leturcq, Renaud [Institute of Electronics Microelectronics and Nanotechnology, UMR CNRS 8520, ISEN Department, Avenue Poincare, CS60069, 59652 Villeneuve d' Ascq Cedex (France); Caroff, Philippe [Institute of Electronics Microelectronics and Nanotechnology, UMR CNRS 8520, ISEN Department, Avenue Poincare, CS60069, 59652 Villeneuve d' Ascq Cedex (France); Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia)

    2013-06-03

    We have investigated in situ Si doping of InAs nanowires grown by molecular beam epitaxy from gold seeds. The effectiveness of n-type doping is confirmed by electrical measurements showing an increase of the electron density with the Si flux. We also observe an increase of the electron density along the nanowires from the tip to the base, attributed to the dopant incorporation on the nanowire facets whereas no detectable incorporation occurs through the seed. Furthermore, the Si incorporation strongly influences the lateral growth of the nanowires without giving rise to significant tapering, revealing the complex interplay between axial and lateral growth.

  7. Interlayer exchange coupling, crystalline and magnetic structure in Fe/CsCl-FeSi multilayers grown by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Dekoster, J.; Degroote, S.; Meersschaut, J.; Moons, R.; Vantomme, A. [K.U. Leuven, Instituut voor Kern- en Stralingsfysica (Belgium); Bottyan, L.; Deak, L.; Szilagyi, E.; Nagy, D.L. [KFKI Research Institute for Particle and Nuclear Physics (Hungary); Baron, A.Q.R. [European Synchrotron Radiation Facility (France); Langouche, G. [K.U. Leuven, Instituut voor Kern- en Stralingsfysica (Belgium)

    1999-09-15

    Crystalline and magnetic structure as well as the interlayer exchange coupling in MBE grown Fe/FeSi multilayers are investigated. From conversion electron Moessbauer spectroscopy and ion beam channeling measurements the spacer FeSi material is found to be stabilized in a crystalline metastable metallic FeSi phase with the CsCl structure. Strong non-oscillatory interlayer exchange coupling is identified with magnetometry and synchrotron Moessbauer reflectometry. From the fits of the time spectrum and the resonant {phi}-{phi} scans a model for the sublayer magnetization of the multilayer is deduced.

  8. Epitaxial growth of SrTiO3 thin film on Si by laser molecular beam epitaxy

    International Nuclear Information System (INIS)

    Zhou, X. Y.; Miao, J.; Dai, J. Y.; Chan, H. L. W.; Choy, C. L.; Wang, Y.; Li, Q.

    2007-01-01

    SrTiO 3 thin films have been deposited on Si (001) wafers by laser molecular beam epitaxy using an ultrathin Sr layer as the template. X-ray diffraction measurements indicated that SrTiO 3 was well crystallized and epitaxially aligned with Si. Cross-sectional observations in a transmission electron microscope revealed that the SrTiO 3 /Si interface was sharp, smooth, and fully crystallized. The thickness of the Sr template was found to be a critical factor that influenced the quality of SrTiO 3 and the interfacial structure. Electrical measurements revealed that the SrTiO 3 film was highly resistive

  9. Growth of high-quality hexagonal InN on 3C-SiC (001) by molecular beam epitaxy

    International Nuclear Information System (INIS)

    Yaguchi, Hiroyuki; Hijikata, Yasuto; Yoshida, Sadafumi; Kitamura, Yoshihiro; Nishida, Kenji; Iwahashi, Yohei

    2005-01-01

    We have grown hexagonal InN (h-InN) films on 3C-SiC (001) substrates by RF-N 2 plasma molecular beam epitaxy taking account of small lattice mismatch between h-InN (10-10) and 3C-SiC (110). It was found from X-ray diffraction (XRD) measurements that h-InN grows with h-InN (0001) vertical stroke vertical stroke 3C-SiC (001) and h-InN (1-100) vertical stroke vertical stroke 3C-SiC (110). XRD measurements also revealed that the h-InN epitaxial layers grown on 3C-SiC (001) are composed of single domain. Strong and sharp photoluminescence from the h-InN was clearly observed at around 0.69 eV. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  10. Ge films grown on Si substrates by molecular-beam epitaxy below 450 deg. C

    International Nuclear Information System (INIS)

    Liu, J.; Kim, H.J.; Hul'ko, O.; Xie, Y.H.; Sahni, S.; Bandaru, P.; Yablonovitch, E.

    2004-01-01

    Ge thin films are grown on Si(001) substrates by molecular-beam epitaxy at 370 deg. C. The low-temperature epitaxial growth is compatible with the back-end thermal budget of current generation complementary metal-oxide-semiconductor technology, which is restricted to less than 450 deg. C. Reflection high-energy electron diffraction shows that single-crystal Ge thin films with smooth surfaces could be achieved below 450 deg. C. Double-axis x-ray θ/2θ scans also show that the epitaxial Ge films are almost fully strain-relaxed. As expected, cross-sectional transmission electron microscopy shows a network of dislocations at the interface. Hydrogen and oxide desorption techniques are proved to be necessary for improving the quality of the Ge films, which is reflected in improved minority carrier diffusion lengths and exceptionally low leakage currents

  11. Exploring of defects in He+ implanted Si(100) by slow positron beam

    International Nuclear Information System (INIS)

    Zhang Tianhao; Weng Huimin; Fan Yangmei; Du Jiangfeng; Zhou Xianyi; Han Rongdian; Zhang Miao; Lin Chenglu

    2001-01-01

    Si(100) crystal implanted by 5 x 10 16 cm -2 , 140 keV He + was probed by slow positron beam, and defect distribution along depth was obtained from the relation between S parameter and positron incidence energy. The near surface region of implanted sample was only slightly damaged. Small vacancies and vacancy clusters less than 1 nm in diameter were the dominant defects, while the deeper region around the He + projected range was heavily damaged and had dense larger helium micro-bubbles and microvoids. Thermal anneal study at different temperatures showed that low temperature annealing could remove most vacancy-type defects effectively. However, annealing at high temperature enlarged the diameters of micro-bubbles and microvoids

  12. Ion beam synthesis and characterization of large area 3C-SiC pseudo substrates for homo- and heteroepitaxy

    International Nuclear Information System (INIS)

    Haeberlen, Maik

    2006-12-01

    In this work, large area epitaxial 3C-SiC films on Si(100) and Si(111) were formed by ion beam synthesis and subsequently characterized for their structural and crystalline properties. These SiC/Si structures are meant to be used as SiC pseudosubstrates for the homo- and heteroepitaxial growth of other compound semiconductors. The suitability of these pseudosubstrates for this purpose was tested using various epitaxial systems and thin film growth methods. For this the homoepitaxial growth of 3C-SiC employing C 60 -MBE and the heteroepitaxial growth of hexagonal GaN films grown by MOCVD and IBAMBA was studied in detail. The comparison of the structural and crystalline properties with data from literature enabled a qualified judgement of the potential of the 3C-SiC pseudosubstrates as an alternative substrate for the epitaxial growth of such films. These new 3C-SiC pseudosubstrates also enabled studies of other little known epitaxial systems: For the first time hexagonal ZnO films on (111) oriented pseudosubstrates were grown using PLD. The method if IBAMBE enabled the growth of cubic GaN layers on (100)-oriented pseudosubstrates. (orig.)

  13. Development of picosecond pulsed electron beam monitor

    International Nuclear Information System (INIS)

    Hosono, Y.; Nakazawa, M.; Ueda, T.; Kobayasi, T.; Yosida, Y.; Ohkuma, J.; Okuda, S.; Suemine, S.

    1993-01-01

    For the picosecond pulsed electron beam of a linear accelerator a simple monitor using an electric connector has been developed which is constructed with SMA, BNC, N type electric connector through pipe (inner diameter = 50 mm or 100 mm). Under the measurement conditions of peak current (26A-900A) and narrow pulse width (Pw = 10 ps(FWHM), Pw = 30 ps(FWHM)), the following characteristics of this monitor were obtained, (A) rise time is less than 25 ps (B) the amplitude of the monitor output pulse is proportional directly to the area of cross section of the electrode. (author)

  14. Conduction mechanism in electron beam irradiated Al/n-Si Schottky diode

    International Nuclear Information System (INIS)

    Vali, Indudhar Panduranga; Shetty, Pramoda Kumara; Mahesha, M.G.; Petwal, V.C.

    2016-01-01

    In the high energy physics experiments, silicon based diodes are used to fabricate radiation detector to detect the charged particles. The Schottky barrier diodes have been studied extensively to understand the behavior of metal semiconductor interface, since such interfaces have been utilized as typical contacts in silicon devices. Because of surface states, interfacial layer, microscopic clusters of metal-semiconductor phases and other effects, it is difficult to fabricate junctions with barriers near the ideal values predicted from the work functions of the two isolated materials, therefore measured barrier heights are used in the device design. In this work, the Al/n-Si Schottky contacts are employed to study the diode parameters (Schottky barrier height and ideality factor), where the Schottky contacts were fabricated on electron beam irradiated silicon wafers. The interface behavior between electron irradiated Si wafer and post metal deposition is so far not reported. This method could be an alternative way to tailor the Schottky barrier height (SBH) without subjecting semiconductor sample to pre chemical and/or post heat treatments during fabrication

  15. aSi EPIDs for the in-vivo dosimetry of static and dynamic beams

    Science.gov (United States)

    Piermattei, A.; Cilla, S.; Azario, L.; Greco, F.; Russo, M.; Grusio, M.; Orlandini, L.; Fidanzio, A.

    2015-10-01

    Portal imaging by amorphous silicon (aSi) photodiode is currently the most applied technology for in-vivo dosimetry (IVD) of static and dynamic radiotherapy beams. The strategy, adopted in this work to perform the IVD procedure by aSi EPID, is based on: in patient reconstruction of the isocenter dose and day to day comparison between 2D-portal images to verify the reproducibility of treatment delivery. About 20.000 tests have been carried out in this last 3 years in 8 radiotherapy centers using the SOFTDISO program. The IVD results show that: (i) the procedure can be implemented for linacs of different manufacturer, (ii) the IVD analysis can be obtained on a computer screen, in quasi real time (about 2 min after the treatment delivery) and (iii) once the causes of the discrepancies were eliminated, all the global IVD tests for single patient were within the acceptance criteria defined by: ±5% for the isocenter dose, and PγFisica Nucleare (INFN) and Università Cattolica del S.Cuore (UCSC).

  16. Xe{sup +} ion beam induced rippled structures on Si miscut wafers

    Energy Technology Data Exchange (ETDEWEB)

    Hanisch, Antje; Grenzer, Joerg [Forschungszentrum Dresden-Rossendorf, Dresden (Germany); Biermanns, Andreas; Pietsch, Ullrich [Institute of Physics, University of Siegen (Germany)

    2009-07-01

    We report on the influence of the initial roughness and crystallography of the substrate on the formation of self-organized ripple structures on semiconductors surfaces by noble gas ion bombardment. The Bradley-Harper theory predicts that an initial roughness is most important for starting the sputtering process which in the ends leads to the evolution of regular patterns. We produced periodic structures with intermediate Xe{sup +} ion energies (5-70 keV) at different incidence and azimuthal angles which lead to the assumption that also crystallography plays a role at the beginning of ripple evolution. Most of the previous investigations started from the original roughness of a polished silicon wafer. We used (001) silicon wafers with a miscut angle of 1 , 5 and 10 towards[110]. We studied the ripple formation keeping the ion beam parallel to the[111],[-1-11] or[-111] direction, i.e. parallel, antiparallel or perpendicular to the miscut direction[110]. The parallel and antiparallel case implies a variation of the incidence angle with increased roughness over the surface step terraces. The perpendicular orientation means almost no roughness. The results were compared to normal Si(001) and Si(111) wafers.

  17. On-beam calibration of the ΔE(Si)-Sci/PD charged particle telescope

    International Nuclear Information System (INIS)

    Avdeichikov, V.; Jakobsson, B.; Nikitin, V.A.; Nomokonov, P.V.; Veldhuizen, E.J. van

    2001-01-01

    The reaction products emitted in the 14 N(45A MeV)+(CH 2 /CD 2 ) interactions are identified by a ΔE(Si)-E(Scintillator/Photodiode) telescope by the conventional ΔE-E method. The position of 'jumps' in the amplitude of the photodiode signal for ions passing through the scintillator (Sci) is used to calibrate on-beam both the ΔE and the Sci/PD scales in MeV. The accuracy of an absolute energy calibration is better than 2.3% and 1.8% for CsI(Tl) and GSO(Ce) detectors, respectively. It is defined mostly by the correctness of the range-energy relations of ions in the Si and Sci crystals. The light response function, L(E,Z,A), of isotopes up to Z(A)=8(16) in the range of energy ∼(2.5-60)A MeV is extracted. The effects of doping concentration and pulse shaping on the light response are analyzed. The validity of the existing empirical light-energy relations is checked in a wide interval of ion energies and a new power law relation is proposed. Calculations of the response function based on the Murray-Mayer model are found to be in excellent agreement with experimental data for the CsI(Tl) crystal

  18. On-beam calibration of the {delta}E(Si)-Sci/PD charged particle telescope

    Energy Technology Data Exchange (ETDEWEB)

    Avdeichikov, V. E-mail: vladimir.Avdeichikov@kosufy.lu.se; Jakobsson, B.; Nikitin, V.A.; Nomokonov, P.V.; Veldhuizen, E.J. van

    2001-07-11

    The reaction products emitted in the {sup 14}N(45A MeV)+(CH{sub 2}/CD{sub 2}) interactions are identified by a {delta}E(Si)-E(Scintillator/Photodiode) telescope by the conventional {delta}E-E method. The position of 'jumps' in the amplitude of the photodiode signal for ions passing through the scintillator (Sci) is used to calibrate on-beam both the {delta}E and the Sci/PD scales in MeV. The accuracy of an absolute energy calibration is better than 2.3% and 1.8% for CsI(Tl) and GSO(Ce) detectors, respectively. It is defined mostly by the correctness of the range-energy relations of ions in the Si and Sci crystals. The light response function, L(E,Z,A), of isotopes up to Z(A)=8(16) in the range of energy {approx}(2.5-60)A MeV is extracted. The effects of doping concentration and pulse shaping on the light response are analyzed. The validity of the existing empirical light-energy relations is checked in a wide interval of ion energies and a new power law relation is proposed. Calculations of the response function based on the Murray-Mayer model are found to be in excellent agreement with experimental data for the CsI(Tl) crystal.

  19. Technique development for modulus, microcracking, hermeticity, and coating evaluation capability characterization of SiC/SiC tubes

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Xunxiang [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Ang, Caen K. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Singh, Gyanender P. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Katoh, Yutai [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

    2016-08-01

    Driven by the need to enlarge the safety margins of nuclear fission reactors in accident scenarios, research and development of accident-tolerant fuel has become an important topic in the nuclear engineering and materials community. A continuous-fiber SiC/SiC composite is under consideration as a replacement for traditional zirconium alloy cladding owing to its high-temperature stability, chemical inertness, and exceptional irradiation resistance. An important task is the development of characterization techniques for SiC/SiC cladding, since traditional work using rectangular bars or disks cannot directly provide useful information on the properties of SiC/SiC composite tubes for fuel cladding applications. At Oak Ridge National Laboratory, experimental capabilities are under development to characterize the modulus, microcracking, and hermeticity of as-fabricated, as-irradiated SiC/SiC composite tubes. Resonant ultrasound spectroscopy has been validated as a promising technique to evaluate the elastic properties of SiC/SiC composite tubes and microcracking within the material. A similar technique, impulse excitation, is efficient in determining the basic mechanical properties of SiC bars prepared by chemical vapor deposition; it also has potential for application in studying the mechanical properties of SiC/SiC composite tubes. Complete evaluation of the quality of the developed coatings, a major mitigation strategy against gas permeation and hydrothermal corrosion, requires the deployment of various experimental techniques, such as scratch indentation, tensile pulling-off tests, and scanning electron microscopy. In addition, a comprehensive permeation test station is being established to assess the hermeticity of SiC/SiC composite tubes and to determine the H/D/He permeability of SiC/SiC composites. This report summarizes the current status of the development of these experimental capabilities.

  20. Research and development of advanced materials using ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Namba, Susumu [Nagasaki Inst. of Applied Science, Nagasaki (Japan)

    1997-03-01

    A wide range of research and development activities of advanced material synthesis using ion beams will be discussed, including ion beam applications to the state-of-the-art electronics from giant to nano electronics. (author)

  1. Development of disease animal models using proton beam

    International Nuclear Information System (INIS)

    Nam, K. H.; Kim, E. K.; Kim, H. R.; Seo, Y. W.

    2010-03-01

    To identify proper proton beam dose for mutant mouse development, total 7 times of proton beam were performed. There are too low incidence of mutation in pup mouse which were derived embryos radiated by 1Gy proton beam. Some mutation could be identified in pup mice which were derived embryos radiated by 1.5-2.5Gy proton beam. Mouse embryos irradiated with 1-10Gy of proton beam were inhibited in their in vitro development to 2 cell stage. There was no pups born from embryos which were irradiated with proton beam over 3 Gy. Early mouse development were greatly inhibited by proton beam irradiation of over 10Gy when cultured in vitro. In conclusion, it is efficient to irradiate mouse embryo with 1.5-2.5Gy of proton beam for development of mutant mice

  2. Selective area growth of InAs nanowires from SiO2/Si(1 1 1) templates direct-written by focused helium ion beam technology

    Science.gov (United States)

    Yang, Che-Wei; Chen, Wei-Chieh; Chou, Chieh; Lin, Hao-Hsiung

    2018-02-01

    We report on the selective area growth of InAs nanowires on patterned SiO2/Si (1 1 1) nano-holes, prepared by focused helium ion beam technology. We used a single spot mode, in which the focused helium ion beam was fixed on a single point with a He+-ion dosage, ranging from 1.5 pC to 8 pC, to drill the nano-holes. The smallest hole diameter achieved is ∼8 nm. We found that low He+-ion dosage is able to facilitate the nucleation of (1 1 1)B InAs on the highly mismatched Si, leading to the vertical growth of InAs nanowires (NWs). High He-ion dosage, on the contrary, severely damaged Si surface, resulting in tilted and stripe-like NWs. In addition to titled NW grown from (1 1 1)A InAs domain, a new titled growth direction due to defect induced twinning was observed. Cross-sectional TEM images of vertical NWs show mixed wurtizite (WZ) and zincblende (ZB) phases, while WZ phase dominants. The stacking faults resulting from the phase change is proportional to NW diameter, suggesting that the critical diameter of phase turning is larger than 110 nm, the maximum diameter of our NWs. Period of misfit dislocation at the InAs/Si interface of vertical NW is also found larger than the theoretical value when the diameter of heterointerface is smaller than 50 nm, indicating that the small contact area is able to accommodate the large lattice and thermal mismatch between InAs and Si.

  3. Photocarrier radiometry for predicting the degradation of electrical parameters of monocrystalline silicon (c-Si) solar cell irradiated by 100 KeV proton beams

    Energy Technology Data Exchange (ETDEWEB)

    Song, P. [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China); Liu, J.Y., E-mail: ljywlj@hit.edu.cn [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China); State Key Laboratory of Robotics and System (HIT), Harbin 150001 (China); Yuan, H.M.; Oliullah, Md.; Wang, F. [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China); Wang, Y., E-mail: songpengkevin@126.com [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China); State Key Laboratory of Robotics and System (HIT), Harbin 150001 (China)

    2016-09-15

    In this study, the monocrystalline silicon (c-Si) solar cell irradiated by 100 KeV proton beams at various fluences is investigated. A one-dimensional two-layer carrier density wave model has been developed to estimate the minority carrier lifetime of n-region and p-region of the non-irradiated c-Si solar cell by best fitting with the experimental photocarrier radiometry (PCR) signal (the amplitude and the phase). Furthermore, the lifetime is used to determine the initial defect density of the quasi-neutral region (QNR) of the solar cell to predict its I–V characteristics. The theoretically predicted short-circuit current density (J{sub sc}), and open-circuit voltage (V{sub oc}) of the non-irradiated samples are in good agreement with experiment. Then a three-region defect distribution model for the c-Si solar cell irradiated by proton beams is carried out to describe the defect density distribution according to Monte Carlo simulation results and the initial defect density of the non-irradiated sample. Finally, we find that the electrical measurements of J{sub sc} and V{sub oc} of the solar cells irradiated at different fluences using 100 KeV proton beams are consistent with the PCR predicting results.

  4. Photocarrier radiometry for predicting the degradation of electrical parameters of monocrystalline silicon (c-Si) solar cell irradiated by 100 KeV proton beams

    International Nuclear Information System (INIS)

    Song, P.; Liu, J.Y.; Yuan, H.M.; Oliullah, Md.; Wang, F.; Wang, Y.

    2016-01-01

    In this study, the monocrystalline silicon (c-Si) solar cell irradiated by 100 KeV proton beams at various fluences is investigated. A one-dimensional two-layer carrier density wave model has been developed to estimate the minority carrier lifetime of n-region and p-region of the non-irradiated c-Si solar cell by best fitting with the experimental photocarrier radiometry (PCR) signal (the amplitude and the phase). Furthermore, the lifetime is used to determine the initial defect density of the quasi-neutral region (QNR) of the solar cell to predict its I–V characteristics. The theoretically predicted short-circuit current density (J_s_c), and open-circuit voltage (V_o_c) of the non-irradiated samples are in good agreement with experiment. Then a three-region defect distribution model for the c-Si solar cell irradiated by proton beams is carried out to describe the defect density distribution according to Monte Carlo simulation results and the initial defect density of the non-irradiated sample. Finally, we find that the electrical measurements of J_s_c and V_o_c of the solar cells irradiated at different fluences using 100 KeV proton beams are consistent with the PCR predicting results.

  5. Modification of H2O adsorbed Si(100)-(2 x 1) surface by photon and electron beam

    International Nuclear Information System (INIS)

    Moon, S.W.; Chung, S.M.; Hwang, C.C.; Ihm, K.W.; Kang, T.-H.; Chen, C.H.; Park, C.-Y.

    2004-01-01

    Full text: Oxidation of silicon has been the subject of intense scientific and technological interest due to the several uses of thin oxide films as insulating layers in microelectronic devices. The great strides have been made in understanding about the formation and thermal evolution of the Si/SiO 2 interface. In this presentation, we provide synchrotron radiation photoemission spectroscopy (SRPES) and photoemission electron microscope (PEEM) results, showing how a H 2 O adsorbed Si(100) surface evolves into an ultra-thin silicon oxide m when exposed to monochromatized synchrotron radiation and electron beam at room temperature. All SRPES, PEEM experiments have been performed at the beam line, 4B1, of Pohang Light Source (PLS) in Korea. Water dissociates into OH(a) and H(a) species upon adsorption on the Si(100)-(2 - 1) at room temperature. The bonding (b 2 ) and antibonding (a 1 ) OH orbital and the oxygen lone pair orbital (b 1 ) from the dissociated OH and H species has been identified in ultraviolet photoemission spectra (UPS). These structures gradually changed and a new silicon oxide peak appeared with the photon/E-beam irradiation. This indicates that the H 2 O adsorbed on Si surface transforms into a thin silicon oxide film by photon/E-beam irradiation. We have shown in our PEEM images that one can make micro-patterns on silicon surface by using the photon induced surface modification. The fabricated patterns can be clearly identified through the inverse contrast images between photon exposed region and unexposed one. The near edge x-ray absorption fine structure (NEXAFS) results revealed that the OH adsorbed Si surface transforms into a thin silicon oxide film by photon irradiation

  6. Formation of hexagonal silicon carbide by high energy ion beam irradiation on Si (1 0 0) substrate

    International Nuclear Information System (INIS)

    Bhuyan, H; Favre, M; Valderrama, E; Avaria, G; Chuaqui, H; Mitchell, I; Wyndham, E; Saavedra, R; Paulraj, M

    2007-01-01

    We report the investigation of high energy ion beam irradiation on Si (1 0 0) substrates at room temperature using a low energy plasma focus (PF) device operating in methane gas. The unexposed and ion exposed substrates were characterized by x-ray diffraction, scanning electron microscopy (SEM), photothermal beam deflection, energy-dispersive x-ray analysis and atomic force microscopy (AFM) and the results are reported. The interaction of the pulsed PF ion beams, with characteristic energy in the 60-450 keV range, with the Si surface, results in the formation of a surface layer of hexagonal silicon carbide. The SEM and AFM analyses indicate clear step bunching on the silicon carbide surface with an average step height of 50 nm and a terrace width of 800 nm

  7. Growth of fullerene on Ag and hydrogen-passivated Si substrates: Effect of electron beam exposure on growth modes

    International Nuclear Information System (INIS)

    Rundhe, M.V.; Dev, B.N.

    2008-01-01

    We have used Auger electron spectroscopy (AES) to investigate the effect of electron beam exposure on growth modes of fullerene (C 60 ) on substrates like Ag and hydrogen-passivated Si(1 1 1). The electron beam comprises of 3.4 keV electrons, which are used in the AES study. To investigate the effect, Auger signal (AS) vs. deposition time (t) measurements were conducted in a sequential mode, i.e., alternating deposition of C 60 and analysis using the electron beam. Duration of AES data collection after each deposition was the duration of exposure to electron beam in this experiment. For the growth study of C 60 on Ag, three AS-t plots were recorded for three different durations of exposure to electron beam. Changes in the AS-t plot, depending on the duration of exposure to the electron beam, reflect the electron beam-induced damage. Electron beam-induced damages of C 60 produce carbon materials of different densities and consequently transmission coefficient (α) of Auger electron through this material changes. In order to fit the AES (AS vs. t) data a model has been used which simultaneously provides the growth mode and the transmission coefficient. Observation of an increasing transmission coefficient with the increasing duration of exposure to the electron beam from α=0.34 to 0.60 indicates the change of the nature of the carbon material due to the partial damage of C 60

  8. Unraveling the role of SiC or Si substrates in water vapor incorporation in SiO 2 films thermally grown using ion beam analyses

    Science.gov (United States)

    Corrêa, S. A.; Soares, G. V.; Radtke, C.; Stedile, F. C.

    2012-02-01

    The incorporation of water vapor in SiO 2 films thermally grown on 6H-SiC(0 0 0 1) and on Si (0 0 1) was investigated using nuclear reaction analyses. Water isotopically enriched in deuterium ( 2H or D) and in 18O was used. The dependence of incorporated D with the water annealing temperature and initial oxide thickness were inspected. The D amount in SiO 2/SiC structures increases continuously with temperature and with initial oxide thickness, being incorporated in the surface, bulk, and interface regions of SiO 2 films. However, in SiO 2/Si, D is observed mostly in near-surface regions of the oxide and no remarkable dependence with temperature or initial oxide thickness was observed. At any annealing temperature, oxygen from water vapor was incorporated in all depths of the oxide films grown on SiC, in contrast with the SiO 2/Si.

  9. Endotaxially stabilized B2-FeSi nanodots in Si (100) via ion beam co-sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Cassidy, Cathal, E-mail: c.cassidy@oist.jp; Singh, Vidyadhar; Grammatikopoulos, Panagiotis [Nanoparticles by Design Unit, Okinawa Institute of Science and Technology (OIST) Graduate University, 1919-1 Onna-Son, Okinawa 904-0495 (Japan); Kioseoglou, Joseph [Department of Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki (Greece); Lal, Chhagan [Department of Physics, University of Rajasthan, Jaipur, Rajasthan 302005 (India); Sowwan, Mukhles, E-mail: mukhles@oist.jp [Nanoparticles by Design Unit, Okinawa Institute of Science and Technology (OIST) Graduate University, 1919-1 Onna-Son, Okinawa 904-0495 (Japan); Nanotechnology Research Laboratory, Al-Quds University, East Jerusalem, P.O. Box 51000, Palestine (Country Unknown)

    2014-04-21

    We report on the formation of embedded B2-FeSi nanodots in [100]-oriented Si substrates, and investigate the crystallographic mechanism underlying the stabilization of this uncommon, bulk-unstable, phase. The nanodots were approximately 10 nm in size, and were formed by iron thin film deposition and subsequent annealing. Cross-sectional transmission electron microscopy, energy loss spectroscopy mapping, and quantitative image simulation and analysis were utilized to identify the phase, strain, and orientational relationship of the nanodots to the host silicon lattice. X-ray photoelectron spectroscopy was utilized to analyze the surface composition and local bonding. Elasticity calculations yielded a nanodot residual strain value of −18%. Geometrical phase analysis graphically pinpointed the positions of misfit dislocations, and clearly showed the presence of pinned (11{sup ¯}1{sup ¯}){sub Si}//(100){sub FeSi}, and unpinned (2{sup ¯}42){sub Si}//(010){sub FeSi}, interfaces. This partial endotaxy in the host silicon lattice was the mechanism that stabilized the B2-FeSi phase.

  10. Advanced Environmental Barrier Coating Development for SiC-SiC Ceramic Matrix Composite Components

    Science.gov (United States)

    Zhu, Dongming; Harder, Bryan; Hurst, Janet B.; Halbig, Michael Charles; Puleo, Bernadette J.; Costa, Gustavo; Mccue, Terry R.

    2017-01-01

    This presentation reviews the NASA advanced environmental barrier coating (EBC) system development for SiC-SiC Ceramic Matrix Composite (CMC) combustors particularly under the NASA Environmentally Responsible Aviation, Fundamental Aeronautics and Transformative Aeronautics Concepts Programs. The emphases have been placed on the current design challenges of the 2700-3000F capable environmental barrier coatings for low NOX emission combustors for next generation turbine engines by using advanced plasma spray based processes, and the coating processing and integration with SiC-SiC CMCs and component systems. The developments also have included candidate coating composition system designs, degradation mechanisms, performance evaluation and down-selects; the processing optimizations using TriplexPro Air Plasma Spray Low Pressure Plasma Spray (LPPS), Plasma Spray Physical Vapor Deposition and demonstration of EBC-CMC systems. This presentation also highlights the EBC-CMC system temperature capability and durability improvements under the NASA development programs, as demonstrated in the simulated engine high heat flux, combustion environments, in conjunction with high heat flux, mechanical creep and fatigue loading testing conditions.

  11. Development and Performance Evaluations of HfO2-Si and Rare Earth-Si Based Environmental Barrier Bond Coat Systems for SiC/SiC Ceramic Matrix Composites

    Science.gov (United States)

    Zhu, Dongming

    2014-01-01

    Ceramic environmental barrier coatings (EBC) and SiCSiC ceramic matrix composites (CMCs) will play a crucial role in future aircraft propulsion systems because of their ability to significantly increase engine operating temperatures, improve component durability, reduce engine weight and cooling requirements. Advanced EBC systems for SiCSiC CMC turbine and combustor hot section components are currently being developed to meet future turbine engine emission and performance goals. One of the significant material development challenges for the high temperature CMC components is to develop prime-reliant, high strength and high temperature capable environmental barrier coating bond coat systems, since the current silicon bond coat cannot meet the advanced EBC-CMC temperature and stability requirements. In this paper, advanced NASA HfO2-Si based EBC bond coat systems for SiCSiC CMC combustor and turbine airfoil applications are investigated. The coating design approach and stability requirements are specifically emphasized, with the development and implementation focusing on Plasma Sprayed (PS) and Electron Beam-Physic Vapor Deposited (EB-PVD) coating systems and the composition optimizations. High temperature properties of the HfO2-Si based bond coat systems, including the strength, fracture toughness, creep resistance, and oxidation resistance were evaluated in the temperature range of 1200 to 1500 C. Thermal gradient heat flux low cycle fatigue and furnace cyclic oxidation durability tests were also performed at temperatures up to 1500 C. The coating strength improvements, degradation and failure modes of the environmental barrier coating bond coat systems on SiCSiC CMCs tested in simulated stress-environment interactions are briefly discussed and supported by modeling. The performance enhancements of the HfO2-Si bond coat systems with rare earth element dopants and rare earth-silicon based bond coats are also highlighted. The advanced bond coat systems, when

  12. Electron-impact ionization of SiCl{sub 3} using an improved crossed fast-neutral-beam - electron-beam apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Mahoney, J M; Gutkin, M V; Tarnovsky, V; Becker, K [Department of Physics and Engineering Physics, Stevens Institute of Technology, Hoboken, NJ 07030 (United States)], E-mail: kbecker@poly.edu

    2008-05-15

    The fast-neutral-beam technique is a versatile approach to the determination of absolute cross sections for electron-impact ionization of atoms, stable molecules as well as free radicals and metastable species. A fast neutral beam of the species under study is prepared by charge-transfer neutralization of a mass-selected ion beam and the species are subsequently ionized by an electron beam. Mass- and energy-dispersive selection separates singly from multiply charged ions and parent from fragment ions and allows the determination of partial ionization cross sections. Here we describe some major improvements that were made recently to the fast-beam apparatus that has been used extensively for ionization cross section measurements for the past 15 years in our group. Experiments using well-established ionization cross sections in conjunction with extensive ion trajectory simulations were carried out to test the satisfactory performance of the modified fast-neutral-beam apparatus. We also report absolute partial cross sections for the formation of various singly charged positive ions produced by electron impact on SiCl{sub 3} for impact energies from threshold to 200 eV in the modified fast-beam apparatus.

  13. The CALICE hadron calorimeters - beam test results and new developments

    International Nuclear Information System (INIS)

    Cvach, J.

    2009-01-01

    A prototype of a highly granular CALICE scintillator-steel hadron calorimeter using SiPMs as photodetectors has been tested in electron and hadron beams at CERN and Fermilab in the energy range 1-80 GeV. More than 7600 SiPMs - the highest number ever used - performed well over a period longer than 2 years and did not show an increase of noise. The electron data were used to validate the detector understanding and its calibration. The analysis of the first part of data from hadron beams leads to the energy resolution of 61% which can be further improved to 49% applying energy dependent weights. The data on the longitudinal and transverse shower shapes allow discrimination among hadronization models of GEANT4. Specifically QGSP B ERT and LHEP predictions were compared to the data. The beam test data allow in situ calibration possibilities to be evaluated. The next step in the calorimeter development for the ILD detector of the ILC, is the construction of a technical prototype - a calorimeter wedge segment of dimensions 80 x 110 x 230 cm 3 with most of the front-end and calibration electronics included in the detector volume. The electronics aims at several new goals - power pulsing, auto-triggering, analogue pipelining and ADC and TDC integration. We also present the alternative concept of a Digital Hadron Calorimeter (DHCAL) for use in a detector optimized for the application of Particle Flow Algorithms to the measurement of jet energies. We report on two lines of R being pursued by the CALICE Collaboration following different read-out and integration concepts. Both are based on glass resistive pad chambers with 1 cm 2 pad read-out, alternative amplification techniques like GEMs or Micromegas are also being considered. One series of studies applies a single threshold (1-bit) to the signal charges, providing digital readout with the front end part integrated on the pad board. We report on detailed measurements with a small scale prototype in the Fermilab test beam

  14. Development of the TFTR neutral beam injection system

    International Nuclear Information System (INIS)

    Prichard, B.A. Jr.

    1977-01-01

    The TFTR Neutral Beam Lines are designed to inject 20 MW of 120 keV neutral deuterium atoms into the plasma. This is accomplished using 12 sources, 65 amperes each, mounted in 4 beam lines. The 120 kV sources and a prototype beam line are being developed. The implementation of these beam lines has required the development of several associated pieces of hardware. 200 kV switch tubes for the power supplies are being developed for modulation and regulation of the accelerating supplies. A 90 cm metallic seal gate valve capable of sealing against atmosphere in either direction is being developed for separating the torus and beam line vacuum systems. A 70 x 80 cm fast shutter valve is also being developed to limit tritium migration from the torus into the beam line. Internal to the beam line a calorimeter, ion dump and deflection magnet have been designed to handle three beams, and optical diagnostics utilizing the doppler broadening and doppler shift of light emitted from the accelerated beam are being developed. The control and monitoring of the 12 sources will be done via the TFTR computer control system (CICADA) as will other parts of the machine, and software is being developed to condition and operate the sources automatically. The prototype beam line is scheduled to begin operation in the fall of 1978 and all four production beam lines on TFTR in 1982

  15. Practical applications of SiC-MOSFETs and further developments

    Science.gov (United States)

    Furuhashi, Masayuki; Tomohisa, Shingo; Kuroiwa, Takeharu; Yamakawa, Satoshi

    2016-03-01

    The next generation power modules using SiC-MOSFETs have been developed for over ten years. From our successful results, we have released SiC power modules which have been used in railway vehicles, industrial machines and home appliances, etc. Low on-resistance 3.3 kV SiC-MOSFETs have been realized by JFET doping and they demonstrated a loss reduction of 55% in a traction inverter compared to a conventional system. In the case of a 1.2 kV MOSFET, a 1 cm2 die verified that it can control a large current of over 600 A. For home appliances, we reduce the trade-off between the threshold voltage and channel mobility by a new gate oxide process. High threshold voltage SiC-MOSFETs having a low on-resistance contribute to the low cost installation of SiC-MOSFETs into air conditioners and achieved a loss reduction of 45% in DC converters. For further reduction of conduction loss, we investigated new structures and technologies. Trench SiC-MOSFETs having a bottom p-well verify lower on-resistance and a larger SCSOA than those of planar MOSFETs. The optimization of the dopant concentration in the drift layer and a reduction of wafer thickness verified the reduction of on-resistance. They are expected to contribute to a lower power loss.

  16. Practical applications of SiC-MOSFETs and further developments

    International Nuclear Information System (INIS)

    Furuhashi, Masayuki; Tomohisa, Shingo; Kuroiwa, Takeharu; Yamakawa, Satoshi

    2016-01-01

    The next generation power modules using SiC-MOSFETs have been developed for over ten years. From our successful results, we have released SiC power modules which have been used in railway vehicles, industrial machines and home appliances, etc. Low on-resistance 3.3 kV SiC-MOSFETs have been realized by JFET doping and they demonstrated a loss reduction of 55% in a traction inverter compared to a conventional system. In the case of a 1.2 kV MOSFET, a 1 cm 2 die verified that it can control a large current of over 600 A. For home appliances, we reduce the trade-off between the threshold voltage and channel mobility by a new gate oxide process. High threshold voltage SiC-MOSFETs having a low on-resistance contribute to the low cost installation of SiC-MOSFETs into air conditioners and achieved a loss reduction of 45% in DC converters. For further reduction of conduction loss, we investigated new structures and technologies. Trench SiC-MOSFETs having a bottom p-well verify lower on-resistance and a larger SCSOA than those of planar MOSFETs. The optimization of the dopant concentration in the drift layer and a reduction of wafer thickness verified the reduction of on-resistance. They are expected to contribute to a lower power loss. (paper)

  17. Beam Delivery Simulation - Recent Developments and Optimization

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00232566; Boogert, Stewart Takashi; Garcia-Morales, H; Gibson, Stephen; Kwee-Hinzmann, Regina; Nevay, Laurence James; Deacon, Lawrence Charles

    2015-01-01

    Beam Delivery Simulation (BDSIM) is a particle tracking code that simulates the passage of particles through both the magnetic accelerator lattice as well as their interaction with the material of the accelerator itself. The Geant4 toolkit is used to give a full range of physics processes needed to simulate both the interaction of primary particles and the production and subsequent propagation of secondaries. BDSIM has already been used to simulate linear accelerators such as the International Linear Collider (ILC) and the Compact Linear Collider (CLIC), but it has recently been adapted to simulate circular accelerators as well, producing loss maps for the Large Hadron Collider (LHC). In this paper the most recent developments, which extend BDSIM’s functionality as well as improve its efficiency are presented. Improvement and refactorisation of the tracking algorithms are presented alongside improved automatic geometry construction for increased particle tracking speed.

  18. Pulsed ion-beam assisted deposition of Ge nanocrystals on SiO2 for non-volatile memory device

    International Nuclear Information System (INIS)

    Stepina, N.P.; Dvurechenskii, A.V.; Armbrister, V.A.; Kirienko, V.V.; Novikov, P.L.; Kesler, V.G.; Gutakovskii, A.K.; Smagina, Z.V.; Spesivtzev, E.V.

    2008-01-01

    A floating gate memory structure, utilizing Ge nanocrystals (NCs) deposited on tunnel SiO 2 , have been fabricated using pulsed low energy ion-beam induced molecular-beam deposition (MBD) in ultra-high vacuum. The ion-beam action is shown to stimulate the nucleation of Ge NCs when being applied after thin Ge layer deposition. Growth conditions for independent change of NCs size and array density were established allowing to optimize the structure parameters required for memory device. Activation energy E = 0.25 eV was determined from the temperature dependence of NCs array density. Monte Carlo simulation has shown that the process, determining NCs array density, is the surface diffusion. Embedding of the crystalline Ge dots into silicon oxide was carried out by selective oxidation of Si(100)/SiO 2 /Ge(NCs)/poly-Si structure. MOS-capacitor obtained after oxidation showed a hysteresis in its C-V curves attributed to charge retention in the Ge dots

  19. Ultra-low-energy ion-beam synthesis of nanometer-separated Si nanoparticles and Ag nanocrystals 2D layers

    Science.gov (United States)

    Carrada, M.; Haj Salem, A.; Pecassou, B.; Paillard, V.; Ben Assayag, G.

    2018-03-01

    2D networks of Si and Ag nanocrystals have been fabricated in the same SiO2 matrix by Ultra-Low-Energy Ion-Beam-Synthesis. Our synthesis scheme differs from a simple sequential ion implantation and its key point is the control of the matrix integrity through an appropriate intermediate thermal annealing. Si nanocrystal layer is synthesised first due to high thermal budget required for nucleation, while the second Ag nanocrystal plane is formed during a subsequent implantation due to the high diffusivity of Ag in silica. The aim of this work is to show how it is possible to overcome the limitation related to ion mixing and implantation damage to obtain double layers of Si-NCs and Ag-NCs with controlled characteristics. For this, we take advantage of annealing under slight oxidizing ambient to control the oxidation of Si-NCs and the Si excess in the matrix. The nanocrystal characteristics and in particular their position and size can be adjusted thanks to a compromise between the implantation energy, the implanted dose for both Si and Ag ions and the intermediate annealing conditions (atmosphere, temperature and duration).

  20. Application of electron beam irradiation, (1). Development and application of electron beam processors

    International Nuclear Information System (INIS)

    Katsumura, Yosuke

    1994-01-01

    This paper deals with characteristics, equipment (principle and kinds), present conditions, and future issues in the application of electron beam irradiation. Characteristics of electron beams are described in terms of the following: chemical and biological effects of radiation; energy and penetrating power of electron beams; and principle and kinds of electron beam accelerator. Industrial application of electron beam irradiation has advantages of high speed procedure and producibility, less energy, avoidance of poisonous gas, and extreme reduction of organic solvents to be used. The present application of electron beam irradiation cen be divided into the following: (1) hardening of resin or coated membrane; (2) improvement of macromolecular materials; (3) environmental protection; (4) sterilization; (5) food sterilization. The present equipment for electron beam irradiation is introduced according to low energy, medium energy, and high energy equipment. Finally, future issues focuses on (1) the improvement of traceability system and development of electron dosimetric techniques and (2) food sterilization. (N.K.)

  1. Development of the Holifield Radioactive Ion Beam Facility

    International Nuclear Information System (INIS)

    Tatum, B.A.

    1997-01-01

    The Holifield Radioactive Ion Beam Facility (HRIBF) construction project has been completed and the first radioactive ion beam has been successfully accelerated. The project, which began in 1992, has involved numerous facility modifications. The Oak Ridge Isochronous Cyclotron has been converted from an energy booster for heavy ion beams to a light ion accelerator with internal ion source. A target-ion source and mass analysis system have been commissioned as key components of the facility's radioactive ion beam injector to the 25MV tandem electrostatic accelerator. Beam transport lines have been completed, and new diagnostics for very low intensity beams have been developed. Work continues on a unified control system. Development of research quality radioactive beams for the nuclear structure and nuclear astrophysics communities continues. This paper details facility development to date

  2. Low energy beam transport system developments

    Energy Technology Data Exchange (ETDEWEB)

    Dudnikov, V., E-mail: vadim@muonsinc.com [Muons, Inc., Batavia, IL 60510 (United States); Han, B.; Stockli, M.; Welton, R. [ORNL, Oak Ridge, TN 37831 (United States); Dudnikova, G. [University of Maryland, College Park, MD 3261 (United States); Institute of Computational Technologies SBRAS, Novosibirsk (Russian Federation)

    2015-04-08

    For high brightness beam production it is important to preserve the brightness in the low energy beam transport system (LEBT) used to transport and match the ion beams to the next stage of acceleration, usually an RFQ. While electrostatic focusing can be problematic for high current beam transport, reliable electrostatic LEBT operation has been demonstrated with H{sup −} beams up to 60 mA. Now, however, it is commonly accepted that an optimal LEBT for high current accelerator applications consists of focusing solenoids with space charge compensation. Two-solenoid LEBTs are successfully used for high current (>100 mA) proton beam transport. Preservation of low emittances (~0.15 π mm-mrad) requires the addition of a heavy gas (Xe, Kr), which causes ~5% of proton loss in a 1 m long LEBT. Similar Xe densities would be required to preserve low emittances of H{sup −} beams, but such gas densities cause unacceptably high H{sup −} beam losses. A short LEBT with only one short solenoid, movable for RFQ matching, can be used for reduced negative ion stripping. A strong electrostatic-focusing LEBT has been successfully adopted for transport of high current H{sup −} beams in the SNS Front End. Some modifications of such electrostatic LEBTs are expected to improve the reliable transport of intense positive and negative ion beams without greatly degrading their low emittances. We concentrate on processes that determine the beam brightness degradation and on their prevention. Proposed improvements to the SNS electrostatic LEBT are discussed.

  3. Point defects in MnSi and YBCO studied by Doppler Broadening Spectroscopy using a positron beam

    Energy Technology Data Exchange (ETDEWEB)

    Reiner, Markus

    2015-10-28

    The positron beam NEPOMUC was used in order to investigate MnSi and YBa{sub 2}Cu{sub 3}O{sub 7-δ} (YBCO) single crystals. The Doppler broadening of the annihilation radiation of electron-positron pairs was analyzed. Thus, the concentration of Mn vacancies in MnSi crystals was determined. In thin YBCO films, the Doppler broadening is correlated with the oxygen deficiency δ. Its spatial distribution and its high-temperature behavior were studied using positrons.

  4. Development of atomic beam probe for tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Berta, M., E-mail: bertam@sze.hu [Széchenyi István University, EURATOM Association, Győr (Hungary); Institute of Plasma Physics AS CR, v.v.i., Prague (Czech Republic); Anda, G.; Aradi, M.; Bencze, A.; Buday, Cs.; Kiss, I.G.; Tulipán, Sz.; Veres, G.; Zoletnik, S. [Wigner – RCP, HAS, EURATOM Association, Budapest (Hungary); Havlícek, J.; Háček, P. [Institute of Plasma Physics AS CR, v.v.i., Prague (Czech Republic); Charles University in Prague, Faculty of Mathematics and Physics (Czech Republic)

    2013-11-15

    Highlights: • ABP is newly developed diagnostic. • Unique measurement method for the determination of plasma edge current variations caused by different transient events such as ELMs. • The design process has been fruitfully supported by the physically motivated computer simulations. • Li-BES system has been modified accordingly to the needs of the ABP. -- Abstract: The concept and development of a new detection method for light alkali ions stemming from diagnostic beams installed on medium size tokamak is described. The method allows us the simultaneous measurement of plasma density fluctuations and fast variations in poloidal magnetic field, therefore one can infer the fast changes in edge plasma current. The concept has been worked out and the whole design process has been done at Wigner RCP. The test detector with appropriate mechanics and electronics is already installed on COMPASS tokamak. General ion trajectory calculation code (ABPIons) has also been developed. Detailed calculations show the possibility of reconstruction of edge plasma current density profile changes with high temporal resolution, and the possibility of density profile reconstruction with better spatial resolution compared to standard Li-BES measurement, this is important for pedestal studies.

  5. Development of atomic beam probe for tokamaks

    International Nuclear Information System (INIS)

    Berta, M.; Anda, G.; Aradi, M.; Bencze, A.; Buday, Cs.; Kiss, I.G.; Tulipán, Sz.; Veres, G.; Zoletnik, S.; Havlícek, J.; Háček, P.

    2013-01-01

    Highlights: • ABP is newly developed diagnostic. • Unique measurement method for the determination of plasma edge current variations caused by different transient events such as ELMs. • The design process has been fruitfully supported by the physically motivated computer simulations. • Li-BES system has been modified accordingly to the needs of the ABP. -- Abstract: The concept and development of a new detection method for light alkali ions stemming from diagnostic beams installed on medium size tokamak is described. The method allows us the simultaneous measurement of plasma density fluctuations and fast variations in poloidal magnetic field, therefore one can infer the fast changes in edge plasma current. The concept has been worked out and the whole design process has been done at Wigner RCP. The test detector with appropriate mechanics and electronics is already installed on COMPASS tokamak. General ion trajectory calculation code (ABPIons) has also been developed. Detailed calculations show the possibility of reconstruction of edge plasma current density profile changes with high temporal resolution, and the possibility of density profile reconstruction with better spatial resolution compared to standard Li-BES measurement, this is important for pedestal studies

  6. Progress in the development of a SiC{sub f}/SiC creep test

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, M.L.; Lewinsohn, C.A.; Jones, R.H.; Youngblood, G.E.; Garner, F.A. [Pacific Northwest National Lab., Richland, WA (United States); Hecht, S.L.

    1996-10-01

    An effort is now underway to design an experiment that will allow the irradiation creep behavior of SiC{sub f}/SiC composites to be quantified. Numerous difficulties must be overcome to achieve this goal, including determining an appropriate specimen geometry that will fit their radiation volumes available and developing a fabrication procedure for such a specimen. A specimen design has been selected, and development of fabrication methods is proceeding. Thermal and stress analyses are being performed to evaluate the viability of the specimen and to assist with determining the design parameters. A possible alternate type of creep test is also being considered. Progress in each of these areas is described in this report.

  7. Progress in the development of a SiCf/SiC creep test

    International Nuclear Information System (INIS)

    Hamilton, M.L.; Lewinsohn, C.A.; Jones, R.H.; Youngblood, G.E.; Garner, F.A.; Hecht, S.L.

    1996-01-01

    An effort is now underway to design an experiment that will allow the irradiation creep behavior of SiC f /SiC composites to be quantified. Numerous difficulties must be overcome to achieve this goal, including determining an appropriate specimen geometry that will fit their radiation volumes available and developing a fabrication procedure for such a specimen. A specimen design has been selected, and development of fabrication methods is proceeding. Thermal and stress analyses are being performed to evaluate the viability of the specimen and to assist with determining the design parameters. A possible alternate type of creep test is also being considered. Progress in each of these areas is described in this report

  8. Development of a compact 25-channel preamplifier module for Si-pad detectors of the BARC-CPDA

    International Nuclear Information System (INIS)

    Inkar, A.; John, Bency; Vind, R.P.; Kinage, L.; Jangale, R.V.; Biswas, D.C.; Nayak, B.K.

    2011-01-01

    The BARC Charged Particle Detector Array modules use indigenously developed Si pad detectors as their first element. Total number of charge sensitive pre-amplifiers required for the Si-pad detectors is 250. One of the main ideas here is a layout of five pre-amplifiers connected with one Si-pad detector (called a bank of preamplifiers). In the present work, a 25-channel pre-amplifier module that can cater to 5 independent Si-pad detectors, or a five-bank module, has been developed. This module uses pre-amp hybrid chips A1422H from CAEN S.p.A. and is housed in a double width NIM standard box. The module has been tested for performance using proton and ''7Li beams from FOTIA facility, Trombay

  9. Development of advanced neutron beam technology

    Energy Technology Data Exchange (ETDEWEB)

    Seong, B S; Lee, J S; Sim, C M [and others

    2007-06-15

    The purpose of this work is to timely support the national science and technology policy through development of the advanced application techniques for neutron spectrometers, built in the previous project, in order to improve the neutron spectrometer techniques up to the world-class level in both quantity and quality and to reinforce industrial competitiveness. The importance of the research and development (R and D) is as follows: 1. Technological aspects - Development of a high value-added technology through performing the advanced R and D in the broad research areas from basic to applied science and from hard to soft condensed matter using neutron scattering technique. - Achievement of an important role in development of the new technology for the following industries aerospace, defense industry, atomic energy, hydrogen fuel cell etc. by the non-destructive inspection and analysis using neutron radiography. - Development of a system supporting the academic-industry users for the HANARO facility 2. Economical and Industrial Aspects - Essential technology in the industrial application of neutron spectrometer, in the basic and applied research of the diverse materials sciences, and in NT, BT, and IT areas - Broad impact on the economics and the domestic and international collaborative research by using the neutron instruments in the mega-scale research facility, HANARO, that is a unique source of neutron in Korea. 3. Social Aspects - Creating the scientific knowledge and contributing to the advanced industrial society through the neutron beam application - Improving quality of life and building a national consensus on the application of nuclear power by developing the RT fusion technology using the HANARO facility. - Widening the national research area and strengthening the national R and D capability by performing advanced R and D using the HANARO facility.

  10. Development of advanced neutron beam technology

    International Nuclear Information System (INIS)

    Seong, B. S.; Lee, J. S.; Sim, C. M.

    2007-06-01

    The purpose of this work is to timely support the national science and technology policy through development of the advanced application techniques for neutron spectrometers, built in the previous project, in order to improve the neutron spectrometer techniques up to the world-class level in both quantity and quality and to reinforce industrial competitiveness. The importance of the research and development (R and D) is as follows: 1. Technological aspects - Development of a high value-added technology through performing the advanced R and D in the broad research areas from basic to applied science and from hard to soft condensed matter using neutron scattering technique. - Achievement of an important role in development of the new technology for the following industries aerospace, defense industry, atomic energy, hydrogen fuel cell etc. by the non-destructive inspection and analysis using neutron radiography. - Development of a system supporting the academic-industry users for the HANARO facility 2. Economical and Industrial Aspects - Essential technology in the industrial application of neutron spectrometer, in the basic and applied research of the diverse materials sciences, and in NT, BT, and IT areas - Broad impact on the economics and the domestic and international collaborative research by using the neutron instruments in the mega-scale research facility, HANARO, that is a unique source of neutron in Korea. 3. Social Aspects - Creating the scientific knowledge and contributing to the advanced industrial society through the neutron beam application - Improving quality of life and building a national consensus on the application of nuclear power by developing the RT fusion technology using the HANARO facility. - Widening the national research area and strengthening the national R and D capability by performing advanced R and D using the HANARO facility

  11. Study of Radiation Hardness of Gd2SiO5 scintillator for Heavy Ion Beam

    CERN Document Server

    Kawade, K; Itow, Y; Masuda, K; Murakami, T; Sako,T; Suzuki, K; Suzuki, T; Taki, K

    2011-01-01

    Gd2SiO5 (GSO) scintillator has very excellent radiation resistance, a fast decay time and a large light yield. Because of these features, GSO scintillator is a suitable material for high radiation environment experiments such as those encountered at high energy accelerators. The radiation hardness of GSO has been measured with Carbon ion beams at the Heavy Ion Medical Accelerator in Chiba (HIMAC). During two nights of irradiation the GSO received a total radiation dose of 7 × 10$^5$ Gy and no decrease of light yield was observed. On the other hand an increase of light yield by 25% was observed. The increase is proportional to the total dose, increasing at a rate of 0.025%/Gy and saturating at around 1 kGy. Recovery to the initial light yield was also observed during the day between two nights of radiation exposure. The recovery was observed to have a slow exponential time constant of approximately 1.5 × 10$^4$ seconds together with a faster component. In case of the LHCf experiment, a very forward region ex...

  12. Vacancy-type defects induced by grinding of Si wafers studied by monoenergetic positron beams

    Energy Technology Data Exchange (ETDEWEB)

    Uedono, Akira; Yoshihara, Nakaaki [Division of Applied Physics, Faculty of Pure and Applied Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan); Mizushima, Yoriko [Devices and Materials Labs Fujitsu Laboratories Ltd., Atsugi, Kanagawa 243-0197 (Japan); ICE Cube Center, Tokyo Institute of Technology, Yokohama 226-8503 (Japan); Kim, Youngsuk [ICE Cube Center, Tokyo Institute of Technology, Yokohama 226-8503 (Japan); Disco Corporation, Ota, Tokyo 143-8580 (Japan); Nakamura, Tomoji [Devices and Materials Labs Fujitsu Laboratories Ltd., Atsugi, Kanagawa 243-0197 (Japan); Ohba, Takayuki [ICE Cube Center, Tokyo Institute of Technology, Yokohama 226-8503 (Japan); Oshima, Nagayasu; Suzuki, Ryoichi [Research Institute of Instrumentation Frontier, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568 (Japan)

    2014-10-07

    Vacancy-type defects introduced by the grinding of Czochralski-grown Si wafers were studied using monoenergetic positron beams. Measurements of Doppler broadening spectra of the annihilation radiation and the lifetime spectra of positrons showed that vacancy-type defects were introduced in the surface region (<98 nm), and the major defect species were identified as (i) relatively small vacancies incorporated in dislocations and (ii) large vacancy clusters. Annealing experiments showed that the defect concentration decreased with increasing annealing temperature in the range between 100 and 500°C. After 600–700°C annealing, the defect-rich region expanded up to about 170 nm, which was attributed to rearrangements of dislocation networks, and a resultant emission of point defects toward the inside of the sample. Above 800°C, the stability limit of those vacancies was reached and they started to disappear. After the vacancies were annealed out (900°C), oxygen-related defects were the major point defects and they were located at <25 nm.

  13. Modification of composite por -Si/SnOx power ion beam of nanosecond duration

    International Nuclear Information System (INIS)

    Korusenko, P.M.; Bolotov, V.V.; Knyazev, E.V.; Kovivchak, V.S.; Korepanov, A.A.; Nesov, S.N.; Povoroznyuk, S.N.

    2011-01-01

    The results of XPS (X-ray photoelectron spectroscopy), AES (Auger electron spectroscopy) and SEM (Scanning electron microscopy) investigation of tin oxide nanolayers on the samples of the composite por-Si/SnO x with different porosity of the matrix, formed under the influence of a powerful ion beam of nanosecond duration was presented. It is shown that fast melting and crystallization of the surface leads to the formation of globular structures with a typical size of 200 nm. Established that the tin is included in structure of the nanocomposite in the oxidized state with little inclusion of metallic β-tin. With increasing porosity, phase composition of nanolayers of tin is close to the state corresponding to the higher tin oxide SnO 2 . Also shows that with increasing porosity, the intensity of subvalent 4d lines of tin, which is apparently associated with an increased degree of hybridization of the tin atoms and oxygen atoms. According to the results stratified etching was to evaluate the changes of the elemental structure of the composite and the depth of penetration of tin. (authors)

  14. Fabrication of Si surface pattern by Ar beam irradiation and annealing method

    International Nuclear Information System (INIS)

    Zhang, J.; Momota, S.; Maeda, K.; Terauchi, H.; Furuta, M.; Kawaharamura, T.; Nitta, N.; Wang, D.

    2012-01-01

    The fabrication process of crater structures on Si crystal has been studied by an irradiation of Ar beam and a thermal annealing at 600 °C. The fabricated surface was measured by field emission scanning electron microscope and atomic force microscope. The results have shown the controllability of specifications of crater formation such as density, diameter and depth by changing two irradiation parameters, fluence and energy of Ar ions. By changing the fluence over a range of 1 ∼ 10 × 10 16 /cm 2 , we could control a density of crater 0 ∼ 39 counts/100μm 2 . By changing the energy over a range of 90 ∼ 270 keV, we could control a diameter and a depth of crater in 0.8 ∼ 4.1μm and 99 ∼ 229nm, respectively. The present result is consistent with the previously proposed model that the crater structure would be arising from an exfoliated surface layer of silicon. The present result has indicated the possibility of the crater production phenomena as a hopeful method to fabricate the surface pattern on a micro-nano meter scale.

  15. InGaAs quantum dots grown by molecular beam epitaxy for light emission on Si substrates.

    Science.gov (United States)

    Bru-Chevallier, C; El Akra, A; Pelloux-Gervais, D; Dumont, H; Canut, B; Chauvin, N; Regreny, P; Gendry, M; Patriarche, G; Jancu, J M; Even, J; Noe, P; Calvo, V; Salem, B

    2011-10-01

    The aim of this study is to achieve homogeneous, high density and dislocation free InGaAs quantum dots grown by molecular beam epitaxy for light emission on silicon substrates. This work is part of a project which aims at overcoming the severe limitation suffered by silicon regarding its optoelectronic applications, especially efficient light emission device. For this study, one of the key points is to overcome the expected type II InGaAs/Si interface by inserting the InGaAs quantum dots inside a thin silicon quantum well in SiO2 fabricated on a SOI substrate. Confinement effects of the Si/SiO2 quantum well are expected to heighten the indirect silicon bandgap and then give rise to a type I interface with the InGaAs quantum dots. Band structure and optical properties are modeled within the tight binding approximation: direct energy bandgap is demonstrated in SiO2/Si/InAs/Si/SiO2 heterostructures for very thin Si layers and absorption coefficient is calculated. Thinned SOI substrates are successfully prepared using successive etching process resulting in a 2 nm-thick Si layer on top of silica. Another key point to get light emission from InGaAs quantum dots is to avoid any dislocations or defects in the quantum dots. We investigate the quantum dot size distribution, density and structural quality at different V/III beam equivalent pressure ratios, different growth temperatures and as a function of the amount of deposited material. This study was performed for InGaAs quantum dots grown on Si(001) substrates. The capping of InGaAs quantum dots by a silicon epilayer is performed in order to get efficient photoluminescence emission from quantum dots. Scanning transmission electronic microscopy images are used to study the structural quality of the quantum dots. Dislocation free In50Ga50As QDs are successfully obtained on a (001) silicon substrate. The analysis of QDs capped with silicon by Rutherford Backscattering Spectrometry in a channeling geometry is also presented.

  16. A SiPM based real time dosimeter for radiotherapic beams

    Energy Technology Data Exchange (ETDEWEB)

    Berra, A., E-mail: alessandro.berra@gmail.it [Università degli Studi dell' Insubria e INFN sezione di Milano Bicocca, Via Valleggio, 11 22100 Como (Italy); Conti, V. [Ospedale Sant' Anna, Servizio di Fisica Sanitaria, Como (Italy); Lietti, D.; Milan, L.; Novati, C. [Università degli Studi dell' Insubria e INFN sezione di Milano Bicocca, Via Valleggio, 11 22100 Como (Italy); Ostinelli, A. [Ospedale Sant' Anna, Servizio di Fisica Sanitaria, Como (Italy); Prest, M.; Romanó, C. [Università degli Studi dell' Insubria e INFN sezione di Milano Bicocca, Via Valleggio, 11 22100 Como (Italy); Vallazza, E. [INFN sezione di Trieste (Italy)

    2015-02-11

    This paper describes the development of a scintillator dosimeter prototype for radiotherapic applications based on plastic scintillating fibers readout by Silicon PhotoMultipliers. The dosimeter, whose probes are water equivalent, could be used for quality control measurements, beam characterization and in vivo dosimetry, allowing a real time measurement of the dose spatial distribution. This paper describes the preliminary percentual depth dose scan performed with clinical 6 and 18 MV photon beams, comparing the results with a reference curve. The measurements were performed using a Varian Clinac iX linear accelerator at the Radiotherapy Department of the St. Anna Hospital in Como (IT). The prototype has given promising results, allowing real time measurements of relative dose without applying any correction factors.

  17. Development of ion/proton beam equipment for industrial uses

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Byung Ho; Lee, J. H.; Cho, Y. S.; Joo, P. K.; Kang, S. S.; Song, W. S.; Kim, H. J.; Chang, G. H.; Bang, S. W

    1999-12-01

    KAERI has possessed design and fabrication technologies of various ion sources including Duoplasmatron and DuoPiGatron developed by R and D projects of the long-term nuclear technology development program. In order to industrialize ion beam equipments utilizing these ion sources, a technology transfer project for a technology transfer project for a domestic firm has been performed. Under this project, engineers of the firm have been trained through classroom lectures of ion beam principles and OJT, an ion/proton beam equipment (DEMO equipment) has been designed, assembled and commissioned jointly with the engineers. Quality of the ion sources has been quantified, and technologies for ion beam equipment construction, functional test and application research have been developed. The DEMO equipment, which consists of an ion source, power supplies, vacuum, cooling and target systems, has been fabricated and tested to secure stability and reliability for industrial uses. Various characteristic tests including high voltage insulation, beam extraction, beam current measuring, etc. have been performed. This DEMO can be utilized for ion sources development as well as ion beam process development for various industrial products. Engineers of the firm have been trained for the industrialization of ion beam equipment and joined in beam application technology development to create industrial needs of beam equipment. (author)

  18. Site-specific forest-assembly of single-wall carbon nanotubes on electron-beam patterned SiOx/Si substrates

    International Nuclear Information System (INIS)

    Wei Haoyan; Kim, Sang Nyon; Kim, Sejong; Huey, Bryan D.; Papadimitrakopoulos, Fotios; Marcus, Harris L.

    2008-01-01

    Based on electron-beam direct writing on the SiO x /Si substrates, favorable absorption sites for ferric cations (Fe 3+ ions) were created on the surface oxide layer. This allowed Fe 3+ -assisted self-assembled arrays of single-wall carbon nanotube (SWNT) probes to be produced. Auger investigation indicated that the incident energetic electrons depleted oxygen, creating more dangling bonds around Si atoms at the surface of the SiO x layer. This resulted in a distinct difference in the friction forces from unexposed regions as measured by lateral force microscopy (LFM). Atomic force microscopy (AFM) affirmed that the irradiated domains absorbed considerably more Fe 3+ ions upon immersion into pH 2.2 aqueous FeCl 3 solution. This rendered a greater yield of FeO(OH)/FeOCl precipitates, primarily FeO(OH), upon subsequent washing with lightly basic dimethylformamide (DMF) solution. Such selective metal-functionalization established the basis for the subsequent patterned forest-assembly of SWNTs as demonstrated by resonance Raman spectroscopy

  19. Fabrication of nano-scaled polymer-derived SiAlCN ceramic components using focused ion beam

    Science.gov (United States)

    Tian, Ye; Shao, Gang; Wang, Xingwei; An, Linan

    2013-09-01

    Fully dense polymer-derived amorphous silicoaluminum carbonitride (SiAlCN) ceramics were synthesized from polysilazane as preceramic precursors followed by a thermal decomposition process. The nanofabrication of amorphous SiAlCN ceramics was implemented with a focused ion beam (FIB). FIB conditions such as the milling rate, the beam current, and the number of passes were considered. It was found that nanopatterns with a feature size of less than 100 nm could be fabricated onto polymer-derived ceramics (PDCs) precisely and quickly. Specific nanostructures of thin walls, nozzle, and gear have been fabricated as demonstrations, indicating that the FIB technique was a promising method to realize nanostructures on PDCs, especially for microelectromechanical system and micro/nano-sensor applications.

  20. Fabrication of nano-scaled polymer-derived SiAlCN ceramic components using focused ion beam

    International Nuclear Information System (INIS)

    Tian, Ye; Wang, Xingwei; Shao, Gang; An, Linan

    2013-01-01

    Fully dense polymer-derived amorphous silicoaluminum carbonitride (SiAlCN) ceramics were synthesized from polysilazane as preceramic precursors followed by a thermal decomposition process. The nanofabrication of amorphous SiAlCN ceramics was implemented with a focused ion beam (FIB). FIB conditions such as the milling rate, the beam current, and the number of passes were considered. It was found that nanopatterns with a feature size of less than 100 nm could be fabricated onto polymer-derived ceramics (PDCs) precisely and quickly. Specific nanostructures of thin walls, nozzle, and gear have been fabricated as demonstrations, indicating that the FIB technique was a promising method to realize nanostructures on PDCs, especially for microelectromechanical system and micro/nano-sensor applications. (paper)

  1. Development of Emittance Analysis Software for Ion Beam Characterization

    International Nuclear Information System (INIS)

    Padilla, M.J.; Liu, Yuan

    2007-01-01

    Transverse beam emittance is a crucial property of charged particle beams that describes their angular and spatial spread. It is a figure of merit frequently used to determine the quality of ion beams, the compatibility of an ion beam with a given beam transport system, and the ability to suppress neighboring isotopes at on-line mass separator facilities. Generally, a high-quality beam is characterized by a small emittance. In order to determine and improve the quality of ion beams used at the Holifield Radioactive Ion Beam Facility (HRIBF) for nuclear physics and nuclear astrophysics research, the emittances of the ion beams are measured at the off-line Ion Source Test Facilities. In this project, emittance analysis software was developed to perform various data processing tasks for noise reduction, to evaluate root-mean-square emittance, Twiss parameters, and area emittance of different beam fractions. The software also provides 2D and 3D graphical views of the emittance data, beam profiles, emittance contours, and RMS. Noise exclusion is essential for accurate determination of beam emittance values. A Self-Consistent, Unbiased Elliptical Exclusion (SCUBEEx) method is employed. Numerical data analysis techniques such as interpolation and nonlinear fitting are also incorporated into the software. The software will provide a simplified, fast tool for comprehensive emittance analysis. The main functions of the software package have been completed. In preliminary tests with experimental emittance data, the analysis results using the software were shown to be accurate

  2. DEVELOPMENT OF EMITTANCE ANALYSIS SOFTWARE FOR ION BEAM CHARACTERIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Padilla, M. J.; Liu, Y.

    2007-01-01

    Transverse beam emittance is a crucial property of charged particle beams that describes their angular and spatial spread. It is a fi gure of merit frequently used to determine the quality of ion beams, the compatibility of an ion beam with a given beam transport system, and the ability to suppress neighboring isotopes at on-line mass separator facilities. Generally a high quality beam is characterized by a small emittance. In order to determine and improve the quality of ion beams used at the Holifi eld Radioactive Ion beam Facility (HRIBF) for nuclear physics and nuclear astrophysics research, the emittances of the ion beams are measured at the off-line Ion Source Test Facilities. In this project, emittance analysis software was developed to perform various data processing tasks for noise reduction, to evaluate root-mean-square emittance, Twiss parameters, and area emittance of different beam fractions. The software also provides 2D and 3D graphical views of the emittance data, beam profi les, emittance contours, and RMS. Noise exclusion is essential for accurate determination of beam emittance values. A Self-Consistent, Unbiased Elliptical Exclusion (SCUBEEx) method is employed. Numerical data analysis techniques such as interpolation and nonlinear fi tting are also incorporated into the software. The software will provide a simplifi ed, fast tool for comprehensive emittance analysis. The main functions of the software package have been completed. In preliminary tests with experimental emittance data, the analysis results using the software were shown to be accurate.

  3. Development of highly polished, grazing incidence mirrors for synchrotron radiation beam lines at SSRL

    Energy Technology Data Exchange (ETDEWEB)

    Tirsell, K.G.; Berglin, E.J.; Fuchs, B.A.; Holdener, F.R.; Humpal, H.H.; Karpenko, V.P.; Kulkarni, S.; Fantone, S.D.

    1987-08-01

    New platinum-coated grazing incidence mirrors with low surface roughnesses have been developed to focus bending magnet radiation from the SSRL/SLAC SPEAR storage ring on the entrance slits of two Beam Line VIII grating monochromators. The first mirror in the toroidal grating monochromator (TGM) branch is a cooled SiC cylinder capable of absorbing synchrotron radiation power levels of up to 260 watts without excessive distortion. This mirror deflects the beam vertically through a 12/degree/ angle and focuses it sagitally on the TGM entrance slit plane. The second TGM optical element is a fused-silica spherical mirror with a large radius of curvature that deflects the beam vertically through an additional 12/degree/ and focuses it tangentially with 3/1 demagnification. The first mirror in our spherical grating branch is a 5/degree/-vertically deflecting, cooled SiC toroid designed to focus tangentially on the monochromator entrance slits and sagitally in the exit slits. A 4/degree/-deflecting fused silica mirror is used after the exit sites in each beam line to refocus on to the sample. For this application a thin cylinder is bent to approximate an ellipsoid. The mirrors are now installed at SSRL and performance measurements are planned. Qualitatively the focus of the TGM optics at the entrance slit plane appears very good. In this paper we discuss considerations leading to the choice of SiC for each of the two first mirrors. We present highlights of the development of these mirrors with some emphasis on SiC polishing techniques. In addition, the specialized metrology developed to produce the more difficult figure of the toroid will be described. Measured surface roughness and figure results will be presented. 19 refs., 11 figs.

  4. Development of highly polished, grazing incidence mirrors for synchrotron radiation beam lines at SSRL

    International Nuclear Information System (INIS)

    Tirsell, K.G.; Berglin, E.J.; Fuchs, B.A.; Holdener, F.R.; Humpal, H.H.; Karpenko, V.P.; Kulkarni, S.; Fantone, S.D.

    1987-08-01

    New platinum-coated grazing incidence mirrors with low surface roughnesses have been developed to focus bending magnet radiation from the SSRL/SLAC SPEAR storage ring on the entrance slits of two Beam Line VIII grating monochromators. The first mirror in the toroidal grating monochromator (TGM) branch is a cooled SiC cylinder capable of absorbing synchrotron radiation power levels of up to 260 watts without excessive distortion. This mirror deflects the beam vertically through a 12/degree/ angle and focuses it sagitally on the TGM entrance slit plane. The second TGM optical element is a fused-silica spherical mirror with a large radius of curvature that deflects the beam vertically through an additional 12/degree/ and focuses it tangentially with 3/1 demagnification. The first mirror in our spherical grating branch is a 5/degree/-vertically deflecting, cooled SiC toroid designed to focus tangentially on the monochromator entrance slits and sagitally in the exit slits. A 4/degree/-deflecting fused silica mirror is used after the exit sites in each beam line to refocus on to the sample. For this application a thin cylinder is bent to approximate an ellipsoid. The mirrors are now installed at SSRL and performance measurements are planned. Qualitatively the focus of the TGM optics at the entrance slit plane appears very good. In this paper we discuss considerations leading to the choice of SiC for each of the two first mirrors. We present highlights of the development of these mirrors with some emphasis on SiC polishing techniques. In addition, the specialized metrology developed to produce the more difficult figure of the toroid will be described. Measured surface roughness and figure results will be presented. 19 refs., 11 figs

  5. Neutral-beam development plan, FY 1982-1987

    International Nuclear Information System (INIS)

    1981-09-01

    The following chapters are included: (1) status of BNL negative ion source development, (2) source development program plan, (3) status of beam transport and acceleration, (4) accelerator development program plan, (5) neutralizer concepts, (6) neutralization program plan, (7) neutral beam systems, (8) test facilities, (9) program milestones and time schedules, (10) organization and Grumman participation, and (11) funding tables

  6. Development of the TFTR neutral beam injection system

    International Nuclear Information System (INIS)

    Prichard, B.A. Jr.

    1978-01-01

    The TFTR Neutral Beam Lines are designed to inject 20 MW of 120 keV neutral deuterium atoms into the plasma. This is accomplished using 12 sources, 65 amperes each, mounted in 4 beam lines. The 120 kV sources are being developed by LBL and a prototype beam line which will be tested at Berkeley is being developed as a cooperative effort by LLL and LBL. The implementation of these beam lines has required the development of several associated pieces of hardware. The control and monitoring of the 12 sources will be done via the TFTR computer control system (CICADA) as will other parts of the machine, and software is being developed to condition and operate the sources automatically. The prototype beam line is scheduled to begin operation in the fall of 1978 and all four production beam lines on TFTR in 1982

  7. The structural evolution of InN nanorods to microstructures on Si (111) by molecular beam epitaxy

    International Nuclear Information System (INIS)

    Anyebe, E A; Zhuang, Q; Kesaria, M; Krier, A

    2014-01-01

    We report the catalyst free growth of wurtzite InN nanorods (NRs) and microislands on bare Si (111) by plasma-assisted molecular beam epitaxy at various temperatures. The morphological evolution from NRs to three dimensional (3D) islands as a function of growth temperature is investigated. A combination of tapered, non-tapered, and pyramidal InN NRs are observed at 490 °C, whereas the InN evolves to faceted microislands with an increase in growth temperature to 540 °C and further developed to indented and smooth hemispherical structures at extremely high temperatures (630 °C). The evolution from NRs to microislands with increase in growth temperature is attributed to the lowering of the surface free energy of the growing crystals with disproportionate growth velocities along different growth fronts. The preferential adsorption of In atoms on the (0001) c-plane and (10-10) m-plane promotes the growth of NRs at relatively low growth temperature and 3D microislands at higher temperatures. The growth rate imbalance along different planes facilitates the development of facets on 3D microislands. A strong correlation between the morphological and structural properties of the 3D films is established. XRD studies reveal that the NRs and the faceted microislands are crystalline, whereas the hemispherical microislands grown at extremely high growth temperature contain In adlayers. Finally, photoluminescent emissions were observed at ∼0.75 eV from the InN NRs. (paper)

  8. Recent developments in electron beam machine technology

    International Nuclear Information System (INIS)

    Sadat, T.; Ross, A.; Leveziel, H.

    1994-01-01

    Electron beam accelerator provides ionisation energy for industrial processing. Electron beam accelerators are increasingly used for decontamination, conservation and disinfestation of food, for sterilization of medical products, and for polymerisation of materials. These machines are easy to install into a production factory as the radiation stops as soon as the machine is switched off. This safety advantage, together with the flexibility of use of these highly automated machines, has allowed the electron beam accelerator to become an important production tool. (author). 23 refs., 6 figs., 2 tabs

  9. The development of MEMS device packaging technology using proton beam

    International Nuclear Information System (INIS)

    Hyeon, J. W.; Kong, Y. J.; Kim, E. H.; Kim, H. S.; No, S. J.

    2006-05-01

    atmospheric pressure using 8, 13 MeV of proton beam energy, current ranging from 1 μA to 20 μA. which proton beam energy is transported to maximum in bonding interface when thickness of pyrex glass is 0.5, 1 mm. The size of Si wafer and the pyrex glass were 1 cm x 1 cm respectively. Thickness were 650 μm-(Si) and 1 mm-(Pyrex). In our experiments, pyrex glass to Si wafer bonding are successfully achieved without extra heating or electric fields

  10. Development of a high current 60 keV neutral lithium beam injector for beam emission spectroscopy measurements on fusion experiments

    Science.gov (United States)

    Anda, G.; Dunai, D.; Lampert, M.; Krizsanóczi, T.; Németh, J.; Bató, S.; Nam, Y. U.; Hu, G. H.; Zoletnik, S.

    2018-01-01

    A 60 keV neutral lithium beam system was designed and built up for beam emission spectroscopy measurement of edge plasma on the KSTAR and EAST tokamaks. The electron density profile and its fluctuation can be measured using the accelerated lithium beam-based emission spectroscopy system. A thermionic ion source was developed with a SiC heater to emit around 4-5 mA ion current from a 14 mm diameter surface. The ion optic is following the 2 step design used on other devices with small modifications to reach about 2-3 cm beam diameter in the plasma at about 4 m from the ion source. A newly developed recirculating sodium vapour neutralizer neutralizes the accelerated ion beam at around 260-280 °C even during long (manipulation techniques are applied to allow optimization, aiming, cleaning, and beam modulation. The maximum 60 keV beam energy with 4 mA ion current was successfully reached at KSTAR and at EAST. Combined with an efficient observation system, the Li-beam diagnostic enables the measurement of the density profile and fluctuations on the plasma turbulence time scale.

  11. Novel microstructural growth in the surface of Inconel 625 by the addition of SiC under electron beam melting

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, M., E-mail: maqomer@yahoo.com [Physics Division, Pakistan Institute of Nuclear Science and Technology (PINSTECH), P.O. Nilore, Islamabad (Pakistan); Ali, G.; Ahmed, Ejaz; Haq, M.A.; Akhter, J.I. [Physics Division, Pakistan Institute of Nuclear Science and Technology (PINSTECH), P.O. Nilore, Islamabad (Pakistan)

    2011-06-15

    Electron beam melting is being used to modify the microstructure of the surfaces of materials due to its ability to cause localized melting and supercooling of the melt. This article presents an experimental study on the surface modification of Ni-based superalloy (Inconel 625) reinforced with SiC ceramic particles under electron beam melting. Scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction techniques have been applied to characterize the resulted microstructure. The results revealed growth of novel structures like wire, rod, tubular, pyramid, bamboo and tweezers type morphologies in the modified surface. In addition to that fibrous like structure was also observed. Formation of thin carbon sheet has been found at the regions of decomposed SiC. Electron beam modified surface of Inconel 625 alloy has been hardened twice as compared to the as-received samples. Surface hardening effect may be attributed to both the formation of the novel structures as well as the introduction of Si and C atom in the lattice of Inconel 625 alloy.

  12. Novel microstructural growth in the surface of Inconel 625 by the addition of SiC under electron beam melting

    Science.gov (United States)

    Ahmad, M.; Ali, G.; Ahmed, Ejaz; Haq, M. A.; Akhter, J. I.

    2011-06-01

    Electron beam melting is being used to modify the microstructure of the surfaces of materials due to its ability to cause localized melting and supercooling of the melt. This article presents an experimental study on the surface modification of Ni-based superalloy (Inconel 625) reinforced with SiC ceramic particles under electron beam melting. Scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction techniques have been applied to characterize the resulted microstructure. The results revealed growth of novel structures like wire, rod, tubular, pyramid, bamboo and tweezers type morphologies in the modified surface. In addition to that fibrous like structure was also observed. Formation of thin carbon sheet has been found at the regions of decomposed SiC. Electron beam modified surface of Inconel 625 alloy has been hardened twice as compared to the as-received samples. Surface hardening effect may be attributed to both the formation of the novel structures as well as the introduction of Si and C atom in the lattice of Inconel 625 alloy.

  13. Novel microstructural growth in the surface of Inconel 625 by the addition of SiC under electron beam melting

    International Nuclear Information System (INIS)

    Ahmad, M.; Ali, G.; Ahmed, Ejaz; Haq, M.A.; Akhter, J.I.

    2011-01-01

    Electron beam melting is being used to modify the microstructure of the surfaces of materials due to its ability to cause localized melting and supercooling of the melt. This article presents an experimental study on the surface modification of Ni-based superalloy (Inconel 625) reinforced with SiC ceramic particles under electron beam melting. Scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction techniques have been applied to characterize the resulted microstructure. The results revealed growth of novel structures like wire, rod, tubular, pyramid, bamboo and tweezers type morphologies in the modified surface. In addition to that fibrous like structure was also observed. Formation of thin carbon sheet has been found at the regions of decomposed SiC. Electron beam modified surface of Inconel 625 alloy has been hardened twice as compared to the as-received samples. Surface hardening effect may be attributed to both the formation of the novel structures as well as the introduction of Si and C atom in the lattice of Inconel 625 alloy.

  14. Development of focused ion beam systems with various ion species

    International Nuclear Information System (INIS)

    Ji Qing; Leung, K.-N.; King, Tsu-Jae; Jiang Ximan; Appleton, Bill R.

    2005-01-01

    Conventional focused ion beam systems employ a liquid-metal ion source (LMIS) to generate high-brightness beams, such as Ga + beams. Recently there has been an increased need for focused ion beams in areas like biological studies, advanced magnetic-film manufacturing and secondary-ion mass spectroscopy (SIMS). In this article, status of development on focused ion beam systems with ion species such as O 2 + , P + , and B + will be reviewed. Compact columns for forming focused ion beams from low energy (∼3keV), to intermediate energy (∼35keV) are discussed. By using focused ion beams, a SOI MOSFET is fabricated entirely without any masks or resist

  15. Ion beam analysis of the dry thermal oxidation of thin polycrystalline SiGe films

    International Nuclear Information System (INIS)

    Kling, A.; Soares, J.C.; Prieto, A.C.; Jimenez, J.; Rodriguez, A.; Sangrador, J.; Rodriguez, T.

    2005-01-01

    Nanoparticles of Ge embedded in a formed dielectric matrix appear as very promising systems for electronic and photonic applications. We present here an exhaustive characterization of the oxidation process of polycrystalline SiGe layers from the starting of its oxidation process to the total oxidation of it. We have characterized the process by RBS, FTIR and Raman spectroscopy, showing the necessity to use different techniques in order to get a full view of the process. First the Si-Si and Si-Ge bonds are oxidized growing SiO 2 , and Ge segregates from the SiO 2 . As soon as all Si is oxidized GeO 2 is growing gradually. RBS has demonstrated to be very useful to characterize the SiO 2 and the remaining non-oxidized poly-SiGe layer thickness, as well as for the determination of the Ge fraction, where the high sensitivity of this technique allows to explore its whole range. On the other hand, for the reliable determination of the GeO 2 thickness, information on the amount of Ge-O bonding had to be obtained from FTIR spectra. Raman spectroscopy yields detailed information about the oxidation processes for different bonds (Si-Si, Si-Ge, Ge-Ge)

  16. Photoluminescent characteristics of ion beam synthesized Ge nanoparticles in thermally grown SiO2 films

    International Nuclear Information System (INIS)

    Yu, C.F.; Chao, D.S.; Chen, Y.-F.; Liang, J.H.

    2013-01-01

    Prospects of developing into numerous silicon-based optoelectronic applications have prompted many studies on the optical properties of Ge nanoparticles within a silicon oxide (SiO 2 ) matrix. Even with such abundant studies, the fundamental mechanism underlying the Ge nanoparticle-induced photoluminescence (PL) is still an open question. In order to elucidate the mechanism, we dedicate this study to investigating the correlation between the PL properties and microstructure of the Ge nanoparticles synthesized in thermally grown SiO 2 films. Our spectral data show that the peak position, at ∼3.1 eV or 400 nm, of the PL band arising from the Ge nanoparticles was essentially unchanged under different Ge implantation fluences and the temperatures of the following annealing process, whereas the sample preparation parameters modified or even fluctuated (in the case of the annealing temperature) the peak intensity considerably. Given the microscopically observed correlation between the nanoparticle structure and the sample preparation parameters, this phenomenon is consistent with the mechanism in which the oxygen-deficiency-related defects in the Ge/SiO 2 interface act as the major luminescence centers; this mechanism also successfully explains the peak intensity fluctuation with the annealing temperature. Moreover, our FTIR data indicate the formation of GeO x upon ion implantation. Since decreasing of the oxygen-related defects by the GeO x formation is expected to be correlated with the annealing temperature, presence of the GeO x renders further experimental support to the oxygen defect mechanism. This understanding may assist the designing of the manufacturing process to optimize the Ge nanoparticle-based PL materials for different technological applications

  17. Preclinical and clinical development of siRNA-based therapeutics.

    Science.gov (United States)

    Ozcan, Gulnihal; Ozpolat, Bulent; Coleman, Robert L; Sood, Anil K; Lopez-Berestein, Gabriel

    2015-06-29

    The discovery of RNA interference, first in plants and Caenorhabditis elegans and later in mammalian cells, led to the emergence of a transformative view in biomedical research. Knowledge of the multiple actions of non-coding RNAs has truly allowed viewing DNA, RNA and proteins in novel ways. Small interfering RNAs (siRNAs) can be used as tools to study single gene function both in vitro and in vivo and are an attractive new class of therapeutics, especially against undruggable targets for the treatment of cancer and other diseases. Despite the potential of siRNAs in cancer therapy, many challenges remain, including rapid degradation, poor cellular uptake and off-target effects. Rational design strategies, selection algorithms, chemical modifications and nanocarriers offer significant opportunities to overcome these challenges. Here, we review the development of siRNAs as therapeutic agents from early design to clinical trial, with special emphasis on the development of EphA2-targeting siRNAs for ovarian cancer treatment. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Mechanism of the nanoscale localization of Ge quantum dot nucleation on focused ion beam templated Si(001) surfaces

    International Nuclear Information System (INIS)

    Portavoce, A; Kammler, M; Hull, R; Reuter, M C; Ross, F M

    2006-01-01

    We investigate the fundamental mechanism by which self-assembled Ge islands can be nucleated at specific sites on Si(001) using ultra-low-dose focused ion beam (FIB) pre-patterning. Island nucleation is controlled by a nanotopography that forms after the implantation of Ga ions during subsequent thermal annealing of the substrate. This nanotopography evolves during the annealing stage, changing from a nanoscale annular depression associated with each focused ion beam spot to a nanoscale pit, and eventually disappearing (planarizing). The correspondence of Ge quantum dot nucleation sites to the focused ion beam features requires a growth surface upon which the nanotopography is preserved. A further key observation is that the Ge wetting layer thickness is reduced in patterned regions, allowing the formation of islands on the templated regions without nucleation elsewhere. These results provide routes to the greatly enhanced design and control of quantum dot distributions and dimensions

  19. Suppression of dilution in Ni-Cr-Si-B alloy cladding layer by controlling diode laser beam profile

    Science.gov (United States)

    Tanigawa, Daichi; Funada, Yoshinori; Abe, Nobuyuki; Tsukamoto, Masahiro; Hayashi, Yoshihiko; Yamazaki, Hiroyuki; Tatsumi, Yoshihiro; Yoneyama, Mikio

    2018-02-01

    A Ni-Cr-Si-B alloy layer was produced on a type 304 stainless steel plate by laser cladding. In order to produce cladding layer with smooth surface and low dilution, influence of laser beam profile on cladding layer was investigated. A laser beam with a constant spatial intensity at the focus spot was used to suppress droplet formation during the cladding layer formation. This line spot, formed with a focussing unit designed by our group, suppressed droplet generation. The layer formed using this line spot with a constant spatial intensity had a much smoother surface compared to a layer formed using a line spot with a Gaussian-like beam. In addition, the dilution of the former layer was much smaller. These results indicated that a line spot with a constant spatial intensity was more effective in producing a cladding layer with smooth surface and low dilution because it suppressed droplet generation.

  20. Evolution of spirals during molecular beam epitaxy of GaN on 6H-SiC(0001)

    International Nuclear Information System (INIS)

    Cui, Y.; Li, L.

    2002-01-01

    Evolution of spirals during molecular beam epitaxy growth of GaN films on 6H-SiC(0001) was studied by in situ scanning tunneling microscopy. It was found that dislocations emerge at the film surface, creating straight steps with orientation along directions with a density of 10 10 cm -2 for 40-nm-thick films. During subsequent growth, these straight steps wind around dislocations and develop into spirals with a density of 10 9 cm -2 for 100-nm-thick films. The spirals can be classified into three types: single arm, interlocking double arm, and closed loop. The first two types originate from steps with one end pinned, and the third type results from steps with both ends pinned. At film thickness larger than 200 nm, these spirals further evolve into spiral mounds with a density of 10 7 cm -2 . Based on the Burton, Cabrera, and Frank theory, a model is proposed to explain the formation of different types of spirals and the reduction of their densities

  1. Development of gamma spectrometer using silicon photomultiplier (SiPM)

    International Nuclear Information System (INIS)

    Kim, Chan Kyu

    2011-02-01

    Gamma spectroscopy is used to determine the identity and quantity of gamma-emitters in nuclear physics, geochemistry and astrophysics. The scintillation detectors are being used as a gamma spectrometer generally, because of their higher gamma-ray detection efficiency and cheaper price than germanium semi-conductor detectors. A typical scintillation detector is composed of a scintillator, a window, and a photodetector. The photomultiplier (PM) tube has been the most widely used as a photodetector because of its advantages like high sensitivity, high signal-to-noise ratio, and wide dynamic range. Recently, the Silicon Photomultiplier (SiPM) is being studied as a substitute of PM tube. The SiPM has almost same performance compared to PM tube but it has additional advantages; low operating voltage, small volume, and cheap production cost. In this research, the gamma spectrometer using SiPM instead of PM tube is developed. The use of SiPM as a photodetector makes the gamma spectrometer smaller, cheaper, easier to use. For photon transport and collection from the large area scintillator to the small area SiPM, a light guide is applied in this gamma spectrometer system. Before fabrication of light guide, DETECT simulation is performed to study and prospect characteristics of light guide structure. And actual light guides are fabricated on the basis of this simulation result. Poly(methyl methacrylate) (PMMA) is chosen as material of light guide, 5 sample light guides are fabricated in different lengths and coatings. As a scintillator crystal, same NaI(Tl) crystal is chosen. For measurement and analysis of gamma spectrometer system, 3 gamma spectrometer systems are composed: PM tube-based system, PM tube-based system with the light guide, SiPM-based system with the light guide. Through comparison between the results of each gamma spectrometer, the performances of gamma spectrometer system are analyzed by each component. Measurement results of the second system is well

  2. Development of a Compton camera for online ion beam range verification via prompt γ detection

    Energy Technology Data Exchange (ETDEWEB)

    Aldawood, S. [LMU Munich, Garching (Germany); King Saud University, Riyadh (Saudi Arabia); Liprandi, S.; Marinsek, T.; Bortfeldt, J.; Lang, C.; Lutter, R.; Dedes, G.; Parodi, K.; Thirolf, P.G. [LMU Munich, Garching (Germany); Maier, L.; Gernhaeuser, R. [TU Munich, Garching (Germany); Kolff, H. van der [LMU Munich, Garching (Germany); TU Delft (Netherlands); Castelhano, I. [LMU Munich, Garching (Germany); University of Lisbon, Lisbon (Portugal); Schaart, D.R. [TU Delft (Netherlands)

    2015-07-01

    Precise and preferably online ion beam range verification is a mandatory prerequisite to fully exploit the advantages of hadron therapy in cancer treatment. An imaging system is being developed in Garching aiming to detect promptγ rays induced by nuclear reactions between the ion beam and biological tissue. The Compton camera prototype consists of a stack of six customized double-sided Si-strip detectors (DSSSD, 50 x 50 mm{sup 2}, 0.5 mm thick, 128 strips/side) acting as scatterer, while the absorber is formed by a monolithic LaBr{sub 3}:Ce scintillator crystal (50 x 50 x 30 mm{sup 3}) read out by a position-sensitive multi-anode photomultiplier (Hamamatsu H9500). The on going characterization of the Compton camera properties and its individual components both offline in the laboratory as well as online using proton beam are presented.

  3. Accelerator development for a radioactive beam facility based on ATLAS

    International Nuclear Information System (INIS)

    Shepard, K. W.

    1998-01-01

    The existing superconducting linac ATLAS is in many respects an ideal secondary beam accelerator for an ISOL (Isotope separator on-line) type radioactive beam facility. Such a facility would require the addition of two major accelerator elements: a low charge state injector for the existing heavy ion linac, and a primary beam accelerator providing 220 MV of acceleration for protons and light ions. Development work for both of these elements, including the option of superconducting cavities for the primary beam accelerator is discussed

  4. Development of high intensity beam handling system, 4

    International Nuclear Information System (INIS)

    Yamanoi, Yutaka; Tanaka, Kazuhiro; Minakawa, Michifumi

    1992-01-01

    We have constructed the new counter experimental hall at the KEK 12 GeV Proton Synchrotron (KEK-PS) in order to handle high intensity primary proton beams of up to 1x10 3 pps (protons per second), which is one order of magnitude greater than the present beam intensity of the KEK-PS, 1x10 12 pps. New technologies for handling high-intensity beams have, then, been developed and employed in the construction of the new hall. A part of our R/D work on handling high intensity beams will be reported. (author)

  5. Accelerator development for a radioactive beam facility based on ATLAS.

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, K. W.

    1998-01-08

    The existing superconducting linac ATLAS is in many respects an ideal secondary beam accelerator for an ISOL (Isotope separator on-line) type radioactive beam facility. Such a facility would require the addition of two major accelerator elements: a low charge state injector for the existing heavy ion linac, and a primary beam accelerator providing 220 MV of acceleration for protons and light ions. Development work for both of these elements, including the option of superconducting cavities for the primary beam accelerator is discussed.

  6. Selective-area growth of GaN nanowires on SiO{sub 2}-masked Si (111) substrates by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Kruse, J. E.; Doundoulakis, G. [Department of Physics, University of Crete, P. O. Box 2208, 71003 Heraklion (Greece); Institute of Electronic Structure and Laser, Foundation for Research and Technology–Hellas, N. Plastira 100, 70013 Heraklion (Greece); Lymperakis, L. [Max-Planck-Institut für Eisenforschung, Max-Planck-Straße 1, 40237 Düsseldorf (Germany); Eftychis, S.; Georgakilas, A., E-mail: alexandr@physics.uoc.gr [Department of Physics, University of Crete, P. O. Box 2208, 71003 Heraklion (Greece); Adikimenakis, A.; Tsagaraki, K.; Androulidaki, M.; Konstantinidis, G. [Institute of Electronic Structure and Laser, Foundation for Research and Technology–Hellas, N. Plastira 100, 70013 Heraklion (Greece); Olziersky, A.; Dimitrakis, P.; Ioannou-Sougleridis, V.; Normand, P. [Institute of Nanoscience and Nanotechnology, NCSR Demokritos, Patriarchou Grigoriou and Neapoleos 27, 15310 Aghia Paraskevi, Athens (Greece); Koukoula, T.; Kehagias, Th.; Komninou, Ph. [Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)

    2016-06-14

    We analyze a method to selectively grow straight, vertical gallium nitride nanowires by plasma-assisted molecular beam epitaxy (MBE) at sites specified by a silicon oxide mask, which is thermally grown on silicon (111) substrates and patterned by electron-beam lithography and reactive-ion etching. The investigated method requires only one single molecular beam epitaxy MBE growth process, i.e., the SiO{sub 2} mask is formed on silicon instead of on a previously grown GaN or AlN buffer layer. We present a systematic and analytical study involving various mask patterns, characterization by scanning electron microscopy, transmission electron microscopy, and photoluminescence spectroscopy, as well as numerical simulations, to evaluate how the dimensions (window diameter and spacing) of the mask affect the distribution of the nanowires, their morphology, and alignment, as well as their photonic properties. Capabilities and limitations for this method of selective-area growth of nanowires have been identified. A window diameter less than 50 nm and a window spacing larger than 500 nm can provide single nanowire nucleation in nearly all mask windows. The results are consistent with a Ga diffusion length on the silicon dioxide surface in the order of approximately 1 μm.

  7. Flexural Cracks Development in Reinforced Concrete Beams Under ...

    African Journals Online (AJOL)

    This work attempts to describe the stress-strain state of beams which is gradually changing with the number of load cycles applied and, especially, to analyses formation and development of cracks which greatly affect the whole behaviour of the beams. The method of assessment of maximum cracks' width giving good ...

  8. Development of a focused ion beam micromachining system

    Energy Technology Data Exchange (ETDEWEB)

    Pellerin, J.G.; Griffis, D.; Russell, P.E.

    1988-12-01

    Focused ion beams are currently being investigated for many submicron fabrication and analytical purposes. An FIB micromachining system consisting of a UHV vacuum system, a liquid metal ion gun, and a control and data acquisition computer has been constructed. This system is being used to develop nanofabrication and nanomachining techniques involving focused ion beams and scanning tunneling microscopes.

  9. Test beam studies of the light yield, time and coordinate resolutions of scintillator strips with WLS fibers and SiPM readout

    Energy Technology Data Exchange (ETDEWEB)

    Denisov, Dmitri [Fermilab, Batavia IL (United States); Evdokimov, Valery [Institute for High Energy Physics, Protvino (Russian Federation); Lukić, Strahinja; Ujić, Predrag [Vinča Institute, University of Belgrade (Serbia)

    2017-03-11

    Prototype scintilator+WLS strips with SiPM readout for large muon detection systems were tested in the muon beam of the Fermilab Test Beam Facility. Light yield of up to 137 photoelectrons per muon per strip has been observed , as well as time resolution of 330 ps and position resolution along the strip of 5.4 cm.

  10. Large area electron beam diode development

    International Nuclear Information System (INIS)

    Helava, H.; Gilman, C.M.; Stringfield, R.M.; Young, T.

    1983-01-01

    A large area annular electron beam diode has been tested at Physics International Co. on the multi-terawatt PITHON generator. A twelve element post hole convolute converted the coaxial MITL into a triaxial arrangement of anode current return structures both inside and outside the cathode structure. The presence of both inner and outer current return paths provide magnetic pressure balance for the beam, as determined by diode current measurements. X-ray pinhole photographs indicated uniform emission with intensity maxima between the post positions. Current losses in the post hole region were negligible, as evidenced by the absence of damage to the aluminum hardware. Radial electron flow near the cathode ring however did damage the inner anode cylinder between the post positions. Cutting away these regions prevented further damage of the transmission lines

  11. Interface properties of 4H-SiC MOS structures studied by a slow positron beam

    International Nuclear Information System (INIS)

    Maekawa, M.; Kawasuso, A.; Ichimiya, A.; Yoshikawa, M.

    2004-01-01

    Interfacial defects existing near the SiO 2 /SiC interface are an important issue for fabrication of high performance SiC devices. We investigate a thermally grown SiO 2 /SiC layer of 4H-SiC MOS structure by positron annihilation spectroscopy. The Doppler broadening of annihilation quanta was measured as a function of the incident positron energy and the gate bias. Applying a negative gate bias, significant increases in S-parameters were observed. This indicates the migration of implanted positrons towards the SiO 2 /SiC interface and annihilation at interfacial defects. Ultraviolet (UV) ray irradiation was used to extract the influence of the positron trapping to the interfacial states. S-parameters in the interface region were reduced by UV irradiation. This shows that positron trapping probability decreased because the charge state of interfacial defects changed to positive. From the recovery of S-parameters after 24 hours, the interfacial states discharge slowly and exist in large quantities, because the changes of S-parameter by the UV irradiation are larger than changes induced by bias change. (orig.)

  12. Development of Beam Conditions Monitor for the ATLAS experiment

    CERN Document Server

    Dolenc Kittelmann, Irena; Mikuž, M

    2008-01-01

    If there is a failure in an element of the accelerator the resulting beam losses could cause damage to the inner tracking devices of the experiments. This thesis presents the work performed during the development phase of a protection system for the ATLAS experiment at the LHC. The Beam Conditions Monitor (BCM) system is a stand-alone system designed to detect early signs of beam instabilities and trigger a beam abort in case of beam failures. It consists of two detector stations positioned at z=±1.84m from the interaction point. Each station comprises four BCM detector modules installed symmetrically around the beam pipe with sensors located at r=55 mm. This structure will allow distinguishing between anomalous events (beam gas and beam halo interactions, beam instabilities) and normal events due to proton-proton interaction by measuring the time-of-flight as well as the signal pulse amplitude from detector modules on the timescale of nanoseconds. Additionally, the BCM system aims to provide a coarse instan...

  13. Investigation of microstructure and morphology for the Ge on porous silicon/Si substrate hetero-structure obtained by molecular beam epitaxy

    International Nuclear Information System (INIS)

    Gouder, S.; Mahamdi, R.; Aouassa, M.; Escoubas, S.; Favre, L.; Ronda, A.; Berbezier, I.

    2014-01-01

    Thick porous silicon (PS) buffer layers are used as sacrificial layers to epitaxially grow planar and fully relaxed Ge membranes. The single crystal Ge layers have been deposited by molecular beam epitaxy (MBE) on PS substrate. During deposition, the pore network of PS layers has been filled with Ge. We investigate the structure and morphology of PS as fabricated and after annealing at various temperatures. We show that the PS crystalline lattice is distorted and expanded in the direction perpendicular to the substrate plane due to the presence of chemisorbed –OH. An annealing at high temperature (> 500 °C), greatly changes the PS morphology and structure. This change is marked by an increase of the pore diameter while the lattice parameter becomes tensily strained in the plane (compressed in the direction perpendicular). The morphology and structure of Ge layers are investigated by transmission electron microscopy, high resolution X-ray diffraction and atomic force microscopy as a function of the deposition temperature and deposited thickness. The results show that the surface roughness, level of relaxation and Si-Ge intermixing (Ge content) depend on the growth temperature and deposited thickness. Two sub-layers are distinguished: the layer incorporated inside the PS pores (high level of intermixing) and the layer on top of the PS surface (low level of intermixing). When deposited at temperature > 500 °C, the Ge layers are fully relaxed with a top Si 1−x Ge x layer x = 0.74 and a very flat surface. Such layer can serve as fully relaxed ultra-thin SiGe pseudo-substrate with high Ge content. The epitaxy of Ge on sacrificial soft PS pseudo-substrate in the experimental conditions described here provides an easy way to fabricate fully relaxed SiGe pseudo-substrates. Moreover, Ge thin films epitaxially deposited by MBE on PS could be used as relaxed pseudo-substrate in conventional microelectronic technology. - Highlights: • We have developed a rapid and low

  14. Growth of InN on 6H-SiC by plasma assisted molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Brown, April S.; Kim, Tong-Ho; Choi, Soojeong; Wu, Pae; Morse, Michael [Department of Electrical and Computer Engineering, Duke University, 128 Hudson Hall, Durham, NC (United States); Losurdo, Maria; Giangregorio, Maria M.; Bruno, Giovanni [Institute of Inorganic Methodologies and of Plasmas, IMIP-CNR and INSTM UdR Bari, via Orabona, 4, 70126 Bari (Italy); Moto, Akihiro [Innovation Core SEI, Inc., 3235 Kifer Road, Santa Clara, CA 95051 (United States)

    2006-06-15

    We have investigated the growth of InN films by plasma assisted molecular beam epitaxy on the Si-face of 6H-SiC(0001). Growth is performed under In-rich conditions using a two-step process consisting of the deposition of a thin, low-temperature 350 C InN buffer layer, followed by the subsequent deposition of the InN epitaxial layer at 450 C. The effect of buffer annealing is investigated. The structural and optical evolution of the growing layer has been monitored in real time using RHEED and spectroscopic ellipsometry. Structural, morphological, electrical and optic properties are discussed. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Transfer-free synthesis of graphene-like atomically thin carbon films on SiC by ion beam mixing technique

    Science.gov (United States)

    Zhang, Rui; Chen, Fenghua; Wang, Jinbin; Fu, Dejun

    2018-03-01

    Here we demonstrate the synthesis of graphene directly on SiC substrates at 900 °C using ion beam mixing technique with energetic carbon cluster ions on Ni/SiC structures. The thickness of 7-8 nm Ni films was evaporated on the SiC substrates, followed by C cluster ion bombarding. Carbon cluster ions C4 were bombarded at 16 keV with the dosage of 4 × 1016 atoms/cm2. After thermal annealing process Ni silicides were formed, whereas C atoms either from the decomposition of the SiC substrates or the implanted contributes to the graphene synthesis by segregating and precipitating process. The limited solubility of carbon atoms in silicides, involving SiC, Ni2Si, Ni5Si2, Ni3Si, resulted in diffusion and precipitation of carbon atoms to form graphene on top of Ni and the interface of Ni/SiC. The ion beam mixing technique provides an attractive production method of a transfer-free graphene growth on SiC and be compatible with current device fabrication.

  16. Development of splitting convergent beam electron diffraction (SCBED)

    Energy Technology Data Exchange (ETDEWEB)

    Houdellier, Florent, E-mail: Florent.Houdellier@cemes.fr [CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse (France); Röder, Falk [CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse (France); Triebenberg Lab, Institut für Strukturphysik, Technische Universität Dresden, D-01062 Dresden (Germany); Snoeck, Etienne [CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse (France)

    2015-12-15

    Using a combination of condenser electrostatic biprism with dedicated electron optic conditions for sample illumination, we were able to split a convergent beam electron probe focused on the sample in two half focused probes without introducing any tilt between them. As a consequence, a combined convergent beam electron diffraction pattern is obtained in the back focal plane of the objective lens arising from two different sample areas, which could be analyzed in a single pattern. This splitting convergent beam electron diffraction (SCBED) pattern has been tested first on a well-characterized test sample of Si/SiGe multilayers epitaxially grown on a Si substrate. The SCBED pattern contains information from the strained area, which exhibits HOLZ lines broadening induced by surface relaxation, with fine HOLZ lines observed in the unstrained reference part of the sample. These patterns have been analyzed quantitatively using both parts of the SCBED transmitted disk. The fine HOLZ line positions are used to determine the precise acceleration voltage of the microscope while the perturbed HOLZ rocking curves in the stained area are compared to dynamical simulated ones. The combination of these two information leads to a precise evaluation of the sample strain state. Finally, several SCBED setups are proposed to tackle fundamental physics questions as well as applied materials science ones and demonstrate how SCBED has the potential to greatly expand the range of applications of electron diffraction and electron holography. - Highlights: • Using a condenser biprism, we split the CBED pattern in two half-CBED disks. • We have determined the electron optical conditions used to perform various SCBED. • We propose new applications possible for this new SCBED configuration.

  17. Oxide-nitride-oxide dielectric stacks with Si nanoparticles obtained by low-energy ion beam synthesis

    International Nuclear Information System (INIS)

    Ioannou-Sougleridis, V; Dimitrakis, P; Vamvakas, V Em; Normand, P; Bonafos, C; Schamm, S; Mouti, A; Assayag, G Ben; Paillard, V

    2007-01-01

    Formation of a thin band of silicon nanoparticles within silicon nitride films by low-energy (1 keV) silicon ion implantation and subsequent thermal annealing is demonstrated. Electrical characterization of metal-insulator-semiconductor capacitors reveals that oxide/Si-nanoparticles-nitride/oxide dielectric stacks exhibit enhanced charge transfer characteristics between the substrate and the silicon nitride layer compared to dielectric stacks using unimplanted silicon nitride. Attractive results are obtained in terms of write/erase memory characteristics and data retention, indicating the large potential of the low-energy ion-beam-synthesis technique in SONOS memory technology

  18. Broad and focused ion beams Ga+ implantation damage in the fabrication of p+-n Si shallow junctions

    International Nuclear Information System (INIS)

    Steckl, A.J.; Lin, C.M.; Patrizio, D.; Rai, A.K.; Pronko, P.P.

    1989-01-01

    The use of focused and broad beam Ga + implantation for the fabrication of p + -n Si shallow junctions is explored. In particular, the issue of ion induced damage and its effect on diode electrical properties is explored. FIB-fabricated junctions exhibit a deeper junction with lower sheet resistance and higher leakage current than the BB-implanted diodes. TEM analysis exhibits similar amorphization and recrystallization behavior for both implantation techniques with the BB case generating a higher dislocation loop density after a 900 degree C anneal. 6 refs., 5 figs., 1 tab

  19. Polarized infrared reflectance studies for wurtzite InN epilayers on Si(111) grown by molecular beam expitaxy

    International Nuclear Information System (INIS)

    Ooi, P.K.; Lee, S.C.; Ng, S.S.; Hassan, Z.; Abu Hassan, H.; Chen, W.L.

    2011-01-01

    Room temperature polarized infrared reflectance technique is employed to study the optical properties of wurtzite InN epilayers on Si(111) grown by molecular beam expitaxy. The reflection spectra are compared to the calculated spectra generated based on the anisotropic dielectric function model. Good agreement between the measured and calculated spectra is obtained. From the fit of the experimental curve, the reststrahlen parameters at the center of Brillouin zone, the carrier concentration and mobility as well as the epilayers thicknesses are determined. The values of the carrier concentration and mobility are in good agreement with the results obtained from the Hall effects measurements.

  20. The latest development of EAST neutral beam injector

    International Nuclear Information System (INIS)

    Hu Chundong; Xu Yongjian

    2014-01-01

    As the first full superconducting non-circular cross section Tokomak in the world, EAST is used to explore the forefront physics and engineering issues on the construction of Tokomak fusion reactor. Neutral beam injection has been recognized as one of the most effective means for plasma heating. According to the research plan of the EAST physics experiment, a set of neutral beam injector (4∼8 MW, 10∼100 s)will be built and operational in 2014. The paper presents the latest development of EAST neutral beam injector and the latest experiment results of long pulse beam extraction and high power beam extraction are reported, those results show that all targets reach or almost reach the design targets. All these will lay a solid foundation for the achievement of plasma heating and current drive for EAST in 2014. (authors)

  1. Radioactive beam diagnostics status and development at the Spiral facility

    International Nuclear Information System (INIS)

    Chautard, F.; Baelde, J.L.; Bucaille, F.; Duneau, P.; Galard, C.; Le Blay, J.P.; Loyant, J.M.; Martina, L.; Ulrich, M.; Laune, B.

    2001-01-01

    In 2001 the first radioactive beam will be accelerated in the CIME cyclotron of the SPIRAL project at GANIL. In order to be able to tune such low intensity beams in the cyclotron (down to few particles per second), a silicon and a scintillator detectors are mounted on probes. They measure the beam energy and the beam phase/RF in the cyclotron as a function of the radius. Such fragile diagnostics are meant to be used routinely from the control room by non-specialists in instrumentation and in presence of various beam intensities. Therefore, a program is developed to control and secure the acquisition procedure, the measurements and the isochronism correction. Additional detectors are installed at a fixed position in the ejection line before the experimental areas. Additionally, a diamond detector is foreseen to be installed in the machine to be tested in order to ease the CIME operation. (authors)

  2. Ion beam mixing to produce disordered AlSi superconducting alloys

    International Nuclear Information System (INIS)

    Xi Xiaoxing; Ran Qize; Liu Jiarui; Guan Weiyan

    1987-01-01

    Multilayered Al/Si films were bombarded with Ar ions at LHe temperature and superconducting transition temperature Tsub(c) was measured in situ. The highest Tsub(c) thus obtained was 7.53 K. The systematic studies on samples with different compositions suggest that ion induced disorder might be the main reason for Tsub(c) enhancement in these AlSi alloys. (author)

  3. Development of picosecond pulsed electron beam monitor. 2

    International Nuclear Information System (INIS)

    Hosono, Y.; Nakazawa, M.; Ueda, T.

    1994-01-01

    A picosecond pulsed electron beam monitor for a 35 MeV linear accelerator has been developed. The monitor consists of an electric SMA connector and aluminium pipe(inner diameter of 50mm). The following characteristics of this monitor were obtained, (a) the rise time is less than 17.5 ps (b) linearity of the monitor output voltage is proportional to the peak current of beam. It is shown that this monitor can be successfully used for bunch measurements of picosecond pulsed electron beam of 35 MeV linac. (author)

  4. Nucleation sites of Ge nanoislands grown on pit-patterned Si substrate prepared by electron-beam lithography

    Science.gov (United States)

    Smagina, Zh. V.; Zinovyev, V. A.; Rudin, S. A.; Novikov, P. L.; Rodyakina, E. E.; Dvurechenskii, A. V.

    2018-04-01

    Regular pit-patterned Si(001) substrates were prepared by electron-beam lithography followed by plasma chemical etching. The geometry of the pits was controlled by varying the etching conditions and the electron-beam exposure duration. It was shown that the location of three-dimensional (3D) Ge nanoislands subsequently grown on the pit-patterned Si substrates depends on the shape of the pit bottom. In the case of pits having a sharp bottom, 3D Ge islands nucleate inside the pits. For pits with a wide flat bottom, the 3D Ge island nucleation takes place at the pit periphery. This effect is attributed to the strain relaxation depending not only on the initial pit shape, but also on its evolution during the Ge wetting layer deposition. It was shown by Monte Carlo simulations that in the case of a pit with a pointed bottom, the relaxation is most effective inside the pit, while for a pit with a wide bottom, the most relaxed area migrates during Ge deposition from the pit bottom to its edges, where 3D Ge islands nucleate.

  5. Optical beam induced current measurements based on two-photon absorption process in 4H-SiC bipolar diodes

    Energy Technology Data Exchange (ETDEWEB)

    Hamad, H.; Raynaud, C.; Bevilacqua, P.; Tournier, D.; Planson, D. [Ampère Laboratory - UMR 5005, 21, Avenue Jean Capelle, 69621 Villeurbanne Cedex (France); Vergne, B. [Franco-Allemand Institute of Saint-Louis ISL, 5, Rue du Général Cassagnou, 68300 Saint-Louis (France)

    2014-02-24

    Using a pulsed green laser with a wavelength of 532 nm, a duration pulse of ∼1 ns, and a mean power varying between 1 and 100 mW, induced photocurrents have been measured in 4H-SiC bipolar diodes. Considering the photon energy (2.33 eV) and the bandgap of 4H-SiC (3.2 eV), the generation of electron-hole pair by the conventional single photon absorption process should be negligible. The intensity of the measured photocurrents depends quadratically on the power beam intensity. This clearly shows that they are generated using two-photon absorption process. As in conventional OBIC (Optical Beam Induced Current), the measurements give an image of the electric field distribution in the structure under test, and the minority carrier lifetime can be extracted from the decrease of the photocurrent at the edge of the structure. The extracted minority carrier lifetime of 210 ns is consistent with results obtained in case of single photon absorption.

  6. Optical beam induced current measurements based on two-photon absorption process in 4H-SiC bipolar diodes

    International Nuclear Information System (INIS)

    Hamad, H.; Raynaud, C.; Bevilacqua, P.; Tournier, D.; Planson, D.; Vergne, B.

    2014-01-01

    Using a pulsed green laser with a wavelength of 532 nm, a duration pulse of ∼1 ns, and a mean power varying between 1 and 100 mW, induced photocurrents have been measured in 4H-SiC bipolar diodes. Considering the photon energy (2.33 eV) and the bandgap of 4H-SiC (3.2 eV), the generation of electron-hole pair by the conventional single photon absorption process should be negligible. The intensity of the measured photocurrents depends quadratically on the power beam intensity. This clearly shows that they are generated using two-photon absorption process. As in conventional OBIC (Optical Beam Induced Current), the measurements give an image of the electric field distribution in the structure under test, and the minority carrier lifetime can be extracted from the decrease of the photocurrent at the edge of the structure. The extracted minority carrier lifetime of 210 ns is consistent with results obtained in case of single photon absorption

  7. Direct atomic fabrication and dopant positioning in Si using electron beams with active real-time image-based feedback

    Science.gov (United States)

    Jesse, Stephen; Hudak, Bethany M.; Zarkadoula, Eva; Song, Jiaming; Maksov, Artem; Fuentes-Cabrera, Miguel; Ganesh, Panchapakesan; Kravchenko, Ivan; Snijders, Panchapakesan C.; Lupini, Andrew R.; Borisevich, Albina Y.; Kalinin, Sergei V.

    2018-06-01

    Semiconductor fabrication is a mainstay of modern civilization, enabling the myriad applications and technologies that underpin everyday life. However, while sub-10 nanometer devices are already entering the mainstream, the end of the Moore’s law roadmap still lacks tools capable of bulk semiconductor fabrication on sub-nanometer and atomic levels, with probe-based manipulation being explored as the only known pathway. Here we demonstrate that the atomic-sized focused beam of a scanning transmission electron microscope can be used to manipulate semiconductors such as Si on the atomic level, inducing growth of crystalline Si from the amorphous phase, reentrant amorphization, milling, and dopant front motion. These phenomena are visualized in real-time with atomic resolution. We further implement active feedback control based on real-time image analytics to automatically control the e-beam motion, enabling shape control and providing a pathway for atom-by-atom correction of fabricated structures in the near future. These observations open a new epoch for atom-by-atom manufacturing in bulk, the long-held dream of nanotechnology.

  8. Investigation of the effect of the incorporated Fe atoms in the ion-beam induced nanopatterns on Si(001)

    Energy Technology Data Exchange (ETDEWEB)

    Khanbabaee, Behnam; Biermanns, Andreas; Pietsch, Ullrich [Siegen Univ. (Germany). Festkoerperphysik; Cornejo, Marina; Frost, Frank [Leibniz-Institute fuer Oberflaechenmodifizierung e.V. (IOM), Leipzig (Germany)

    2012-07-01

    Ion beam erosion of semiconductor surfaces can modify the surface and depends on main sputtering parameters; different surface topographies such as ripple or dot like pattern are fabricated on the surface. Recent experiments have shown that the incorporation of foreign metallic atoms during the sputtering process plays a crucial role in pattern formation on surfaces. In the result of investigation we report on the depth profile of Fe atoms incorporated in sputtering process on Si(100) with low energy Kr ion beam. X-ray reflectivity (XRR) measurements determine the concentration profile of Fe atoms. X-ray absorption near edge spectroscopy (XANES) at the Fe K-edge (7112 eV) shows the formation of Fe rich silicide near surface region. X-ray photoelectron spectroscopy (XPS) shows a shift in the binding energy of Si2p levels at the surface compared top bulk confirming the formation of different phases of Fe-silicide on tope and below the surface. The depth profiles obtained by XRR are compared to results obtained by complementary secondary-ion mass spectrometry (SIMS).

  9. Direct atomic fabrication and dopant positioning in Si using electron beams with active real-time image-based feedback.

    Science.gov (United States)

    Jesse, Stephen; Hudak, Bethany M; Zarkadoula, Eva; Song, Jiaming; Maksov, Artem; Fuentes-Cabrera, Miguel; Ganesh, Panchapakesan; Kravchenko, Ivan; Snijders, Panchapakesan C; Lupini, Andrew R; Borisevich, Albina Y; Kalinin, Sergei V

    2018-06-22

    Semiconductor fabrication is a mainstay of modern civilization, enabling the myriad applications and technologies that underpin everyday life. However, while sub-10 nanometer devices are already entering the mainstream, the end of the Moore's law roadmap still lacks tools capable of bulk semiconductor fabrication on sub-nanometer and atomic levels, with probe-based manipulation being explored as the only known pathway. Here we demonstrate that the atomic-sized focused beam of a scanning transmission electron microscope can be used to manipulate semiconductors such as Si on the atomic level, inducing growth of crystalline Si from the amorphous phase, reentrant amorphization, milling, and dopant front motion. These phenomena are visualized in real-time with atomic resolution. We further implement active feedback control based on real-time image analytics to automatically control the e-beam motion, enabling shape control and providing a pathway for atom-by-atom correction of fabricated structures in the near future. These observations open a new epoch for atom-by-atom manufacturing in bulk, the long-held dream of nanotechnology.

  10. Development and Commissioning of an External Beam Facility in the Union College Ion Beam Analysis Laboratory

    Science.gov (United States)

    Yoskowitz, Joshua; Clark, Morgan; Labrake, Scott; Vineyard, Michael

    2015-10-01

    We have developed an external beam facility for the 1.1-MV tandem Pelletron accelerator in the Union College Ion Beam Analysis Laboratory. The beam is extracted from an aluminum pipe through a 1 / 4 ' ' diameter window with a 7.5- μm thick Kapton foil. This external beam facility allows us to perform ion beam analysis on samples that cannot be put under vacuum, including wet samples and samples too large to fit into the scattering chamber. We have commissioned the new facility by performing proton induced X-ray emission (PIXE) analysis of several samples of environmental interest. These include samples of artificial turf, running tracks, and a human tooth with an amalgam filling. A 1.7-MeV external proton beam was incident on the samples positioned 2 cm from the window. The resulting X-rays were measured using a silicon drift detector and were analyzed using GUPIX software to determine the concentrations of elements in the samples. The results on the human tooth indicate that while significant concentrations of Hg, Ag, and Sn are present in the amalgam filling, only trace amounts of Hg appear to have leached into the tooth. The artificial turf and running tracks show rather large concentrations of a broad range of elements and trace amounts of Pb in the turf infill.

  11. Non-equilibrium ionization by a periodic electron beam. II. Synthetic Si IV and O IV transition region spectra

    Science.gov (United States)

    Dzifčáková, Elena; Dudík, Jaroslav

    2018-03-01

    Context. Transition region (TR) spectra typically show the Si IV 1402.8 Å line to be enhanced by a factor of 5 or more compared to the neighboring O IV 1401.2 Å, contrary to predictions of ionization equilibrium models and the Maxwellian distribution of particle energies. Non-equilibrium effects in TR spectra are therefore expected. Aims: To investigate the combination of non-equilibrium ionization and high-energy particles, we apply the model of the periodic electron beam, represented by a κ-distribution that recurs at periods of several seconds, to plasma at chromospheric temperatures of 104 K. This simple model can approximate a burst of energy release involving accelerated particles. Methods: Instantaneous time-dependent charge states of silicon and oxygen were calculated and used to synthesize the instantaneous and period-averaged spectra of Si IV and O IV. Results: The electron beam drives the plasma out of equilibrium. At electron densities of Ne = 1010 cm-3, the plasma is out of ionization equilibrium at all times in all cases we considered, while for a higher density of Ne = 1011 cm-3, ionization equilibrium can be reached toward the end of each period, depending on the conditions. In turn, the character of the period-averaged synthetic spectra also depends on the properties of the beam. While the case of κ = 2 results in spectra with strong or even dominant O IV, higher values of κ can approximate a range of observed TR spectra. Spectra similar to typically observed spectra, with the Si IV 1402.8 Å line about a factor 5 higher than O IV 1401.2 Å, are obtained for κ = 3. An even higher value of κ = 5 results in spectra that are exclusively dominated by Si IV, with negligible O IV emission. This is a possible interpretation of the TR spectra of UV (Ellerman) bursts, although an interpretation that requires a density that is 1-3 orders of magnitude lower than for equilibrium estimates. Movies associated to Fig. A.1 are available at http://https://www.aanda.org

  12. High-energy ion-beam-induced phase separation in SiOx films

    International Nuclear Information System (INIS)

    Arnoldbik, W.M.; Tomozeiu, N.; Hattum, E.D. van; Lof, R.W.; Vredenberg, A.M.; Habraken, F.H.P.M.

    2005-01-01

    The modification of the nanostructure of silicon suboxide (SiO x ) films as a result of high-energy heavy-ion irradiation has been studied for the entire range 0.1≤x x films have been obtained by radio-frequency magnetron sputter deposition. For 50 MeV 63 Cu 8+ ions and an angle of incidence of 20 deg. with the plane of the surface, and for x≥0.5, it takes a fluence of about 10 14 /cm 2 to reach a Si-O-Si infrared absorption spectrum, which is supposed to be characteristic for a Si-SiO 2 composite film structure. For smaller x values, it takes a much larger fluence. The interpretation of the IR spectra is corroborated for the surface region by results from x-ray photoelectron spectroscopy. The results present evidence for a mechanism, in which the phase separation takes place in the thermal spike, initiated by the energy deposited in many overlapping independent ion tracks. Such a process is possible since the suboxides fulfill the conditions for spinodal decomposition

  13. Environmental Barrier Coating Development for SiC/SiC Ceramic Matrix Composites: Recent Advances and Future Directions

    Science.gov (United States)

    Zhu, Dongming

    2016-01-01

    This presentation briefly reviews the SiC/SiC major environmental and environment-fatigue degradations encountered in simulated turbine combustion environments, and thus NASA environmental barrier coating system evolution for protecting the SiC/SiC Ceramic Matrix Composites for meeting the engine performance requirements. The presentation will review several generations of NASA EBC materials systems, EBC-CMC component system technologies for SiC/SiC ceramic matrix composite combustors and turbine airfoils, highlighting the temperature capability and durability improvements in simulated engine high heat flux, high pressure, high velocity, and with mechanical creep and fatigue loading conditions. This paper will also focus on the performance requirements and design considerations of environmental barrier coatings for next generation turbine engine applications. The current development emphasis is placed on advanced NASA candidate environmental barrier coating systems for SiC/SiC CMCs, their performance benefits and design limitations in long-term operation and combustion environments. The efforts have been also directed to developing prime-reliant, self-healing 2700F EBC bond coat; and high stability, lower thermal conductivity, and durable EBC top coats. Major technical barriers in developing environmental barrier coating systems, the coating integrations with next generation CMCs having the improved environmental stability, erosion-impact resistance, and long-term fatigue-environment system durability performance will be described. The research and development opportunities for turbine engine environmental barrier coating systems by utilizing improved compositions, state-of-the-art processing methods, and simulated environment testing and durability modeling will be briefly discussed.

  14. Vacancy-type defects and their annealing processes in ion-implanted Si studied by a variable-energy positron beam

    International Nuclear Information System (INIS)

    Uedono, A.; Wei, L.; Tanigawa, S.; Sugiura, J.; Ogasawara, M.

    1992-01-01

    Vacancy-type defects in B + -, P + - and Si + -ion implanted SiO 2 (43 nm)/Si(100) and Si(100) were studied by a variable-energy positron beam. Depth distributions of vacancy-type defects were obtained from measurements of Doppler broadening profiles of the positron annihilation as a function of incident positron energy. For 200-keV P + -implanted specimen with a dose of 5 x 10 13 P/cm 2 , the damaged layers induced by ion-implantation were found to extend far beyond the stopping range of P-atoms. For 80-keV B + -implanted SiO 2 (43 nm)/Si(100) specimens with different ion-currents, an increase of the ion-current introduced a homogeneous amorphous layer in the subsurface region. Dominant defect species in B + - and P + -implanted specimen were identified as vacancy clusters from their annealing behavior. (author)

  15. Effects of recoil-implanted oxygen on depth profiles of defects and annealing processes in P{sup +}-implanted Si studied using monoenergetic positron beams

    Energy Technology Data Exchange (ETDEWEB)

    Uedono, Akira; Moriya, Tsuyoshi; Tanigawa, Shoichiro [Tsukuba Univ., Ibaraki (Japan). Inst. of Materials Science; Kitano, Tomohisa; Watanabe, Masahito; Kawano, Takao; Suzuki, Ryoichi; Ohdaira, Toshiyuki; Mikado, Tomohisa

    1996-04-01

    Effects of oxygen atoms recoiled from SiO{sub 2} films on depth profiles of defects and annealing processes in P{sup +}-implanted Si were studied using monoenergetic positron beams. For an epitaxial Si specimen, the depth profile of defects was found to be shifted toward the surface by recoil implantation of oxygen atoms. This was attributed to the formation of vacancy-oxygen complexes and a resultant decrease in the diffusion length of vacancy-type defects. The recoiled oxygen atoms stabilized amorphous regions introduced by P{sup +}-implantation, and the annealing of these regions was observed after rapid thermal annealing (RTA) at 700degC. For a Czochralski-grown Si specimen fabricated by through-oxide implantation, the recoiled oxygen atoms introduced interstitial-type defects upon RTA below the SiO{sub 2}/Si interface, and such defects were dissociated by annealing at 1000degC. (author)

  16. Enhancement of optical absorption of Si (100) surfaces by low energy N+ ion beam irradiation

    Science.gov (United States)

    Bhowmik, Dipak; Karmakar, Prasanta

    2018-05-01

    The increase of optical absorption efficiency of Si (100) surface by 7 keV and 8 keV N+ ions bombardment has been reported here. A periodic ripple pattern on surface has been observed as well as silicon nitride is formed at the ion impact zones by these low energy N+ ion bombardment [P. Karmakar et al., J. Appl. Phys. 120, 025301 (2016)]. The light absorption efficiency increases due to the presence of silicon nitride compound as well as surface nanopatterns. The Atomic Force Microscopy (AFM) study shows the formation of periodic ripple pattern and increase of surface roughness with N+ ion energy. The enhancement of optical absorption by the ion bombarded Si, compared to the bare Si have been measured by UV - visible spectrophotometer.

  17. Development of an external Faraday cup for beam current measurements

    International Nuclear Information System (INIS)

    Kim, Kye-Ryung; Jung, Myung-Hwan; Ra, Se-Jin; Lee, Seok-Ki

    2010-01-01

    In general, beam current measurements are very important for many kinds of experiments using highly energetic particle beams at accelerators, such as cyclotrons, linacs, etc. The Faraday cup is known to be one of the most popular beam current measurement tools. We developed an external Faraday cup to measure the beam current at a dedicated beam line for low-flux experiments installed at the MC-50 cyclotron of Korea Institute of Radiological and Medical Sciences (KIRAMS). It was designed for external beam current measurements and is composed of a vacuum chamber, an entrance window, a collimator, a electrostatic suppressor ring, and a cup. The window is made of 75-um-thick Kapton film, and the diameter of the collimator is 10 mm or 20 mm. The ring and the cup has 5-cm inner diameters, and the thickness of the bottom of the cup is 2 cm, which is enough to absorb the total proton energy up to 45 MeV. Using this external Faraday cup, we measured the beam current from the cyclotron, and we compared measured flux to the results from film dosimetry using GAF films.

  18. Development of a Supersonic Atomic Oxygen Nozzle Beam Source for Crossed Beam Scattering Experiments

    Science.gov (United States)

    Sibener, S. J.; Buss, R. J.; Lee, Y. T.

    1978-05-01

    A high pressure, supersonic, radio frequency discharge nozzle beam source was developed for the production of intense beams of ground state oxygen atoms. An efficient impedance matching scheme was devised for coupling the radio frequency power to the plasma as a function of both gas pressure and composition. Techniques for localizing the discharge directly behind the orifice of a water-cooled quartz nozzle were also developed. The above combine to yield an atomic oxygen beam source which produces high molecular dissociation in oxygen seeded rare gas mixtures at total pressures up to 200 torr: 80 to 90% dissociation for oxygen/argon mixtures and 60 to 70% for oxygen/helium mixtures. Atomic oxygen intensities are found to be greater than 10{sup 17} atom sr{sup -1} sec{sup -1}. A brief discussion of the reaction dynamics of 0 + IC1 ..-->.. I0 + C1 is also presented.

  19. Development of Beam Utilization Technologies and Support for Users

    International Nuclear Information System (INIS)

    Kim, Kyeryung; Jung, Myunghwan; Noh, Yongoh; Lee, Sooyeon; Kim, Hyukwook; Kil, Jaekeun; Lee, Nayoung; Ra, Sekin; Lee, Miejeen; Kim, Sora

    2013-02-01

    The Final goals are to achieve the 2nd goals of the Proton Engineering Frontier Project, development of proton beam utilization technologies, to incubate the potential users, and to develop fundamental technologies. Based on these achievements, we are going to enhance the accelerator utilization and maximize contribution to the local society after accelerator construction completion. For the these goals, we were operating user program reflecting the results of 3rd step planning. We support 38 small projects during 2 years. As results of activation of beam utilization, we acquired 768 users at the end of 2012. We survey proton beam technology proposals, individuals and institutions participation letter of intent through the research of 'Planning of a support program for both basic research by using accelerator and manpower cultivation'. And inaugurated KOPUA (Korea Proton Accelerator User Association) on March 28, 2012 with 152 members. We secured experimental conditions at TR23 and TR103 and reflected in the target room design and operation scenarios via investigate the requirements. Through these requirements, we make a remote sample transfer system, beam regulating system, hot cell and sample transport container. Moreover, we develop proton beam technologies such as in-vivo proton beam irradiation system, comparison of the biological effects for pulse beam and continuous beam, basic experiments for the metal nanopaticle synthesis, research for radioactivatied samples and devices, conceptual design and calculation for neutron source target and calculation of the isotope production yield. Proton accelerator can be utilized in a variety of field, including NT, BT, IT, ST, ET, Nuclear, medical, and some of the user facilities required were constructed through this project, Experience for the construction and operation of these facilities can be reflected to the construction of the rest 8 target room of proton accelerator center

  20. Secondary growth mechanism of SiGe islands deposited on a mixed-phase microcrystalline Si by ion beam co-sputtering.

    Science.gov (United States)

    Ke, S Y; Yang, J; Qiu, F; Wang, Z Q; Wang, C; Yang, Y

    2015-11-06

    We discuss the SiGe island co-sputtering deposition on a microcrystalline silicon (μc-Si) buffer layer and the secondary island growth based on this pre-SiGe island layer. The growth phenomenon of SiGe islands on crystalline silicon (c-Si) is also investigated for comparison. The pre-SiGe layer grown on μc-Si exhibits a mixed-phase structure, including SiGe islands and amorphous SiGe (a-SiGe) alloy, while the layer deposited on c-Si shows a single-phase island structure. The preferential growth and Ostwald ripening growth are shown to be the secondary growth mechanism of SiGe islands on μc-Si and c-Si, respectively. This difference may result from the effect of amorphous phase Si (AP-Si) in μc-Si on the island growth. In addition, the Si-Ge intermixing behavior of the secondary-grown islands on μc-Si is interpreted by constructing the model of lateral atomic migration, while this behavior on c-Si is ascribed to traditional uphill atomic diffusion. It is found that the aspect ratios of the preferential-grown super islands are higher than those of the Ostwald-ripening ones. The lower lateral growth rate of super islands due to the lower surface energy of AP-Si on the μc-Si buffer layer for the non-wetting of Ge at 700 °C and the stronger Si-Ge intermixing effect at 730 °C may be responsible for this aspect ratio difference.

  1. Microstructural Development in Al-Si Powder During Rapid Solidification

    Energy Technology Data Exchange (ETDEWEB)

    Genau, Amber Lynn [Iowa State Univ., Ames, IA (United States)

    2004-01-01

    Powder metallurgy has become an increasingly important form of metal processing because of its ability to produce materials with superior mechanical properties. These properties are due in part to the unique and often desirable microstructures which arise as a result of the extreme levels of undercooling achieved, especially in the finest size powder, and the subsequent rapid solidification which occurs. A better understanding of the fundamental processes of nucleation and growth is required to further exploit the potential of rapid solidification processing. Aluminum-silicon, an alloy of significant industrial importance, was chosen as a model for simple eutectic systems displaying an unfaceted/faceted interface and skewed coupled eutectic growth zone, Al-Si powder produced by high pressure gas atomization was studied to determine the relationship between microstructure and alloy composition as a function of powder size and atomization gas. Critical experimental measurements of hypereutectic (Si-rich) compositions were used to determine undercooling and interface velocity, based on the theoretical models which are available. Solidification conditions were analyzed as a function of particle diameter and distance from nucleation site. A revised microstructural map is proposed which allows the prediction of particle morphology based on temperature and composition. It is hoped that this work, by providing enhanced understanding of the processes which govern the development of the solidification morphology of gas atomized powder, will eventually allow for better control of processing conditions so that particle microstructures can be optimized for specific applications.

  2. Investigation of the depth profile of ion beam induced nanopatterns on Si with simultaneous metal incorporation

    Energy Technology Data Exchange (ETDEWEB)

    Khanbabaee, Behnam; Arezki, Bahia; Biermanns, Andreas; Pietsch, Ullrich [Festkoerperphysik, Universitaet Siegen, Siegen (Germany); Cornejo, Marina; Frost, Frank [Leibniz-Institut fuer Oberflaechenmodifizierung (IOM), Leipzig (Germany)

    2011-07-01

    Ion beam sputtering of semiconductor surfaces can modify the surface and produce a diversity of surface topographies such as periodic ripples or dot structures depended on sputtering parameters. Well ordered nanostructured surfaces have widely technological applications. Recent experiments have shown that the incorporation of metallic impurity atoms during the sputtering process plays a crucial role in pattern formation on the surfaces. These findings offer a new degree of freedom to control pattern formation. In this contribution we report on surface patterning due to Kr ion beam erosion on silicon surfaces with simultaneous Fe and Cr incorporation. We used X-ray reflectivity (XRR) to determine the depth profiles of metal ions as function of ion beam divergence angles and the mean incidence angle of the ions with respect to the surface normal. Depth profiles are correlated with degree of pattern formation determined by AFM. We show that the mean penetration depth and concentration of metal ions depends on the divergence angle of Kr beam provided by Kaufman source which supports the assumption that metal ions are created due to parasitic interaction of the Kr beam with the steel plate lining. The evaluated depth profile by XRR is in good agreement with SIMS and RBS results.

  3. Design development of bellows for the DNB beam source

    International Nuclear Information System (INIS)

    Singh, Dhananjay Kumar; Venkata Nagaraju, M.; Joshi, Jaydeep; Patel, Hitesh; Yadav, Ashish; Pillai, Suraj; Singh, Mahendrajit; Bandyopadhyay, Mainak; Chakraborty, A.K.; Sharma, Dheeraj

    2017-01-01

    Establishing a procedure and mechanism for alignment of Ion beams in Neutral Beam (NB) sources for ITER like systems are complex due to large traversal distances (∼21 m) and restricted use of flexible elements into the system. For the beam source of DNB, movement requirements for beam alignment are the combination of tilting (±9mrad), rotation (±9mrad) and translation (±25mm). The present work describes the design development of a system composed of three single ply ‘Gimbal’ type bellow system, placed in series, in L-shaped hydraulic lines (size DN50, DN20 and DN15). The paper shall detail out the generation of initial requirements, transformation of movements at bellow locations, selection of bellows/combination of bellows, minimizing the induced movements by optimization of bellows location, estimation of movements through CEASAR II and the design compliance with respect to EJMA code

  4. The development of beam current monitors in the APS

    International Nuclear Information System (INIS)

    Wang, X.; Lenkszus, F.; Rotela, E.

    1995-01-01

    The Advanced Photon Source (APS) is a third-generation 7-GeV synchrotron radiation source. The precision measurement of beam current is a challenging task in high energy accelerators, such as the APS, with a wide range of beam parameters and complicated noise, radiation, and thermal environments. The beam pulses in the APS injector and storage ring have charge ranging from 50pC to 25nC with pulse durations varying from 30ps to 30ns. A total of nine non- intercepting beam current monitors have been installed in the APS facility (excluding those in the linac) for general current measurement. In addition, several independent current monitors with specially designed redundant interlock electronics are installed for personnel safety and machine protection. This paper documents the design and development of current monitors in the APS,. discusses the commissioning experience in the past year, and presents the results of recent operations

  5. Holifield Radioactive Ion Beam Facility Development and Status

    CERN Document Server

    Tatum, Alan

    2005-01-01

    The Holifield Radioactive Ion Beam Facility (HRIBF) is a national user facility dedicated to nuclear structure, reactions, and nuclear astrophysics research with radioactive ion beams (RIBs) using the isotope separator on-line (ISOL) technique. An integrated strategic plan for physics, experimental systems, and RIB production facilities have been developed and implementation of the plan is under way. Specific research objectives are defined for studying the nature of nucleonic matter, the origin of elements, solar physics, and synthesis of heavy elements. Experimental systems upgrade plans include new detector arrays and beam lines, and expansion and upgrade of existing devices. A multifaceted facility expansion plan includes a $4.75M High Power Target Laboratory (HPTL), presently under construction, to provide a facility for testing new target materials, target geometries, ion sources, and beam preparation techniques. Additional planned upgrades include a second RIB production system (IRIS2), an external axi...

  6. Design and development of radiation absorber for sighting beam line

    International Nuclear Information System (INIS)

    Sridhar, R.; Shukla, S.K.

    2005-01-01

    During the commissioning of Indus-2 , it is necessary to view the synchrotron radiation that will be emanating from the dipole exit ports. The 10 0 beam line from dipole 11 was earmarked for sighting beam line. The synchrotron radiation power density would be around 340 watts on the photon absorber inside the radiation absorber module, at the specified beam power of Indus-2. The beam striking on this photon absorber produces x-rays and Bremsstrahlung radiation. These are to be stopped and absorbed by radiation absorber. The photon absorber and the radiation absorber are integrated in a single vacuum chamber and actuated by a pneumatic cylinder connected using a bellow. Radiation absorber was needed to isolate the diagnostic components and to protect them from radiation a well as heat when they were not in use. The paper describes the design, calculation and development of the dynamic photon cum radiation absorber. The ultimate vacuum performance is also described. (author)

  7. Bremsstrahlung and Ion Beam Current Measurements with SuSI ECR Ion Source

    International Nuclear Information System (INIS)

    Ropponen, T.

    2012-01-01

    This series of slides presents: the Superconducting Source for Ions (SuSI), the X-ray measurement setup, the different collimation schemes, the flat B operation versus B(min) operation, and the impact of tuning ∇B while keeping fixed field profile

  8. Formation of Si single-crystal hetero photocells structure by the beam technologies

    International Nuclear Information System (INIS)

    Dovbnya, A.N.; Efimov, V.P.; Efimov, S.V.

    1997-01-01

    To increase the service time of solar photo elements new methods are proposed. One of them consists in three-step conversion of solar spectrum in geterogenic structures. This can solve the problem of light flux control in c-Si semiconductors and to create a silicon photo element of high efficiency and protection from solar plasma particle action

  9. Ion beam synthesis and characterization of large area 3C-SiC pseudo substrates for homo- and heteroepitaxy; Ionenstrahlsynthese und Charakterisierung grossflaechiger 3C-SiC-Pseudosubstrate fuer die Homo- und Heteroepitaxie

    Energy Technology Data Exchange (ETDEWEB)

    Haeberlen, Maik

    2006-12-15

    In this work, large area epitaxial 3C-SiC films on Si(100) and Si(111) were formed by ion beam synthesis and subsequently characterized for their structural and crystalline properties. These SiC/Si structures are meant to be used as SiC pseudosubstrates for the homo- and heteroepitaxial growth of other compound semiconductors. The suitability of these pseudosubstrates for this purpose was tested using various epitaxial systems and thin film growth methods. For this the homoepitaxial growth of 3C-SiC employing C{sub 60}-MBE and the heteroepitaxial growth of hexagonal GaN films grown by MOCVD and IBAMBA was studied in detail. The comparison of the structural and crystalline properties with data from literature enabled a qualified judgement of the potential of the 3C-SiC pseudosubstrates as an alternative substrate for the epitaxial growth of such films. These new 3C-SiC pseudosubstrates also enabled studies of other little known epitaxial systems: For the first time hexagonal ZnO films on (111) oriented pseudosubstrates were grown using PLD. The method if IBAMBE enabled the growth of cubic GaN layers on (100)-oriented pseudosubstrates. (orig.)

  10. Development of a beam ion velocity detector for the heavy ion beam probe

    Energy Technology Data Exchange (ETDEWEB)

    Fimognari, P. J., E-mail: PJFimognari@XanthoTechnologies.com; Crowley, T. P.; Demers, D. R. [Xantho Technologies, LLC, Madison, Wisconsin 53705 (United States)

    2016-11-15

    In an axisymmetric plasma, the conservation of canonical angular momentum constrains heavy ion beam probe (HIBP) trajectories such that measurement of the toroidal velocity component of secondary ions provides a localized determination of the poloidal flux at the volume where they originated. We have developed a prototype detector which is designed to determine the beam angle in one dimension through the detection of ion current landing on two parallel planes of detecting elements. A set of apertures creates a pattern of ion current on wires in the first plane and solid metal plates behind them; the relative amounts detected by the wires and plates determine the angle which beam ions enter the detector, which is used to infer the toroidal velocity component. The design evolved from a series of simulations within which we modeled ion beam velocity changes due to equilibrium and fluctuating magnetic fields, along with the ion beam profile and velocity dispersion, and studied how these and characteristics such as the size, cross section, and spacing of the detector elements affect performance.

  11. Development of a beam ion velocity detector for the heavy ion beam probe

    International Nuclear Information System (INIS)

    Fimognari, P. J.; Crowley, T. P.; Demers, D. R.

    2016-01-01

    In an axisymmetric plasma, the conservation of canonical angular momentum constrains heavy ion beam probe (HIBP) trajectories such that measurement of the toroidal velocity component of secondary ions provides a localized determination of the poloidal flux at the volume where they originated. We have developed a prototype detector which is designed to determine the beam angle in one dimension through the detection of ion current landing on two parallel planes of detecting elements. A set of apertures creates a pattern of ion current on wires in the first plane and solid metal plates behind them; the relative amounts detected by the wires and plates determine the angle which beam ions enter the detector, which is used to infer the toroidal velocity component. The design evolved from a series of simulations within which we modeled ion beam velocity changes due to equilibrium and fluctuating magnetic fields, along with the ion beam profile and velocity dispersion, and studied how these and characteristics such as the size, cross section, and spacing of the detector elements affect performance.

  12. Estimation of interface resistivity in bonded Si for the development of high performance radiation detectors

    International Nuclear Information System (INIS)

    Kanno, Ikuo; Yamashita, Makoto; Nomiya, Seiichiro; Onabe, Hideaki

    2007-01-01

    For the development of high performance radiation detectors, direct bonding of Si wafers would be an useful method. Previously, p-n bonded Si were fabricated and they showed diode characteristics. The interface resistivity was, however, not investigated in detail. For the study of interface resistivity, n-type Si wafers with different resistivities were bonded. The resistivity of bonded Si wafers were measured and the interface resistivity was estimated by comparing with the results of model calculations. (author)

  13. Growth of BaSi2 continuous films on Ge(111) by molecular beam epitaxy and fabrication of p-BaSi2/n-Ge heterojunction solar cells

    Science.gov (United States)

    Takabe, Ryota; Yachi, Suguru; Tsukahara, Daichi; Toko, Kaoru; Suemasu, Takashi

    2017-05-01

    We grew BaSi2 films on Ge(111) substrates by various growth methods based on molecular beam epitaxy (MBE). First, we attempted to form BaSi2 films directly on Ge(111) by MBE without templates. We next formed BaSi2 films using BaGe2 templates as commonly used for MBE growth of BaSi2 on Si substrates. Contrary to our prediction, the lateral growth of BaSi2 was not promoted by these two methods; BaSi2 formed not into a continuous film but into islands. Although streaky patterns of reflection high-energy electron diffraction were observed inside the growth chamber, no X-ray diffraction lines of BaSi2 were observed in samples taken out from the growth chamber. Such BaSi2 islands were easily to get oxidized. We finally attempted to form a continuous BaSi2 template layer on Ge(111) by solid phase epitaxy, that is, the deposition of amorphous Ba-Si layers onto MBE-grown BaSi2 epitaxial islands, followed by post annealing. We achieved the formation of an approximately 5-nm-thick BaSi2 continuous layer by this method. Using this BaSi2 layer as a template, we succeeded in forming a-axis-oriented 520-nm-thick BaSi2 epitaxial films on Ge substrates, although (111)-oriented Si grains were included in the grown layer. We next formed a B-doped p-BaSi2(20 nm)/n-Ge(111) heterojunction solar cell. A wide-spectrum response from 400 to 2000 nm was achieved. At an external bias voltage of 1 V, the external quantum efficiency reached as high as 60%, demonstrating the great potential of BaSi2/Ge combination. However, the efficiency of a solar cell under AM1.5 illumination was quite low (0.1%). The origin of such a low efficiency was examined.

  14. National negative-ion-based neutral-beam development plan

    International Nuclear Information System (INIS)

    Cooper, W.S.; Pyle, R.V.

    1983-08-01

    The plan covers facilities required, program milestones, and decision points. It includes identification of applications, experiments, theoretical research areas, development of specific technologies and reactor development and demonstration facilities required to bring about the successful application of negative-ion-based neutral beams. Particular emphasis is placed on those activities leading to use on existing plasma confinement experiments or their upgrades

  15. BNL neutral-beam development group. Progress report FY 1982

    International Nuclear Information System (INIS)

    Prelec, K.; Sluyters, T.

    1983-01-01

    Efforts were concentrated on the development of H - /D - sources capable of delivering about 1A of beam current, operating steady state at an energy of several tens of keV and having properties that would allow a scaling up to 10A and their use in a high energy neutral beam line. In the seventies we have developed negative ion sources of the plasms surface type with extracted current densities of several hundred mA/cm 2 . Particularly successful was the development of the magnetron source, from which pulsed beam currents in excess of one ampere have been obtained and accelerated up to 120 kV. These magnetrons have become standard sources in high energy accelerator laboratories around the world and they are candidates for application in polarized H - ion sources as well. Work on hollow cathode deuterium sources and neutraizers is reported

  16. Modification of mechanical properties of Si crystal irradiated by Kr-beam

    International Nuclear Information System (INIS)

    Guo, Xiaowei; Momota, Sadao; Nitta, Noriko; Yamaguchi, Takaharu; Sato, Noriyuki; Tokaji, Hideto

    2015-01-01

    Graphical abstract: - Highlights: • Modification of mechanical properties of silicon crystal irradiated by Kr-beam was observed by means of continuous measurements of nano-indentation technique. • Modified mechanical properties show fluence-dependence. • Young's modulus is more sensitive to crystal to amorphous phase transition while hardness is more sensitive to damage induced by ion beam irradiation. • The depth profile of modified mechanical properties have a potential application of determining the longitudinal size of phase transition region induced by nanoindentation. - Abstract: The application of ion-beam irradiation in fabrication of structures with micro-/nanometer scale has achieved striking improvement. However, an inevitable damage results in the change of mechanical properties in irradiated materials. To investigate the relation between mechanical properties and ion-irradiation damages, nanoindentation was performed on crystalline silicon irradiated by Kr-beam with an energy of 240 keV. Modified Young's modulus and nanohardness, provided from the indentation, indicated fluence dependence. Stopping and range of ions in matter (SRIM) calculation, transmission electron microscopy (TEM) observation, and Rutherford backscattering-channeling (RBS-C) measurement were utilized to understand the irradiation effect on mechanical properties. In addition, the longitudinal size of the phase transition region induced by indentation was firstly evaluated based on the depth profile of modified nanohardness

  17. Film Cooled Recession of SiC/SiC Ceramic Matrix Composites: Test Development, CFD Modeling and Experimental Observations

    Science.gov (United States)

    Zhu, Dongming; Sakowski, Barbara A.; Fisher, Caleb

    2014-01-01

    SiCSiC ceramic matrix composites (CMCs) systems will play a crucial role in next generation turbine engines for hot-section component applications because of their ability to significantly increase engine operating temperatures, reduce engine weight and cooling requirements. However, the environmental stability of Si-based ceramics in high pressure, high velocity turbine engine combustion environment is of major concern. The water vapor containing combustion gas leads to accelerated oxidation and corrosion of the SiC based ceramics due to the water vapor reactions with silica (SiO2) scales forming non-protective volatile hydroxide species, resulting in recession of the ceramic components. Although environmental barrier coatings are being developed to help protect the CMC components, there is a need to better understand the fundamental recession behavior of in more realistic cooled engine component environments.In this paper, we describe a comprehensive film cooled high pressure burner rig based testing approach, by using standardized film cooled SiCSiC disc test specimen configurations. The SiCSiC specimens were designed for implementing the burner rig testing in turbine engine relevant combustion environments, obtaining generic film cooled recession rate data under the combustion water vapor conditions, and helping developing the Computational Fluid Dynamics (CFD) film cooled models and performing model validation. Factors affecting the film cooled recession such as temperature, water vapor concentration, combustion gas velocity, and pressure are particularly investigated and modeled, and compared with impingement cooling only recession data in similar combustion flow environments. The experimental and modeling work will help predict the SiCSiC CMC recession behavior, and developing durable CMC systems in complex turbine engine operating conditions.

  18. Displacement of group III, IV, V, and VI impurities in Si by the analyzing beam

    International Nuclear Information System (INIS)

    Wiggers, L.W.; Saris, F.W.

    1978-01-01

    By means of 2MeV He + backscattering and 1.5 MeV H + backscattering and nuclear reaction analysis in combination with the channeling technique displacement of impurity atoms in Si from substitutional into non-substitutional positions under bombardment is studied. In this paper the authors report on the displacement of Ga, Ge, P, As, Sb, Bi, Se, and Te in Si single crystals. It appears that displacement of impurity atoms is not an exception but almost a rule. The only element for which an effect was not found was Ge. Values for the displacement rate were derived and appeared to be, with the exception for Ge, all of the same order of magnitude. (Auth.)

  19. Production of Rare Earth Isotope Beams for Radiotracer-DLTS on SiC

    CERN Multimedia

    2002-01-01

    Electrical properties of semiconductors are extremely sensitive to minor traces of impurities and defects. This fact allows to intentionally modify material properties and is thus the very basis of semiconductor electronics and optoelectronics. In the present project, electronic properties and doping effects of rare-earth elements in the technologically important semiconductor SiC are to be investigated using optical and electrical characterization techniques like Photoluminescence, Deep Level Transient Spectroscopy and Thermal Admittance Spectroscopy. By using the elemental transmutation of radioactive isotopes as a tracer, it will be guaranteed that the impurity-related band gap states can definitively be distinguished from intrinsic or process-induced defects. For SiC up to now only detailed investigation of Er- related deep levels have been reported, preliminary data exist for Sm- and Gd- impurities. In this project we propose the implantation of Pr and Eu isotopes for detailed level studies.

  20. Development of functional polymers by electron beam

    International Nuclear Information System (INIS)

    Okamoto, Jiro

    1992-01-01

    Radiation-induced grafting is known as a method for introducing functional groups in a variety of polymers and inorganic substances. Various radiation grafting methods have been extensively developed in the early years and these have been the basis for radiation grafting research and development since that time. These are the preirradiation, the mutual, and the peroxide methods. Most of these methods investigated have been to create active sites on a polymer backbone by irradiation and reacting these with monomer which can then propagate to form grafted side chains of different structure. In this paper, the radiation grafting methods will be described and discussed in some detail together with their advantages and disadvantages. A few typical examples will be discussed with reference to research and development of functional materials such as ion exchange membrane, pervaporation membrane, fibrous ion exchanger and fibrous chelating agent for metal ions. (author)

  1. Steel-SiC Metal Matrix Composite Development. Final report

    International Nuclear Information System (INIS)

    Smith, Don D.

    2005-01-01

    One of the key materials challenges for Generation IV reactor technology is to improve the strength and resistance to corrosion and radiation damage in the metal cladding of the fuel pins during high-temperature operation. Various candidate Gen IV designs call for increasing core temperature to improve efficiency and facilitate hydrogen production, operation with molten lead moderator to use fast neutrons. Fuel pin lifetime against swelling and fracture is a significant limit in both respects. The goal of this project is to develop a method for fabricating SiC-reinforced high-strength steel. We are developing a metal-matrix composite (MMC) in which SiC fibers are be embedded within a metal matrix of steel, with adequate interfacial bonding to deliver the full benefit of the tensile strength of the SiC fibers in the composite. In the context of the mission of the SBIR program, this Phase I grant has been successful. The development of a means to attain interfacial bonding between metal and ceramic has been a pacing challenge in materials science and technology for a century. It entails matching or grading of thermal expansion across the interface and attaining a graded chemical composition so that impurities do not concentrate at the boundary to create a slip layer. To date these challenges have been solved in only a modest number of pairings of compatible materials, e.g. Kovar and glass, titanium and ceramic, and aluminum and ceramic. The latter two cases have given rise to the only presently available MMC materials, developed for aerospace applications. Those materials have been possible because the matrix metal is highly reactive at elevated temperature so that graded composition and intimate bonding happens naturally at the fiber-matrix interface. For metals that are not highly reactive at processing temperature, however, successful bonding is much more difficult. Recent success has been made with copper MMCs for cooling channels in first-wall designs for fusion

  2. Growth of CdTe on Si(100) surface by ionized cluster beam technique: Experimental and molecular dynamics simulation

    Energy Technology Data Exchange (ETDEWEB)

    Araghi, Houshang, E-mail: araghi@aut.ac.ir [Department of Physics, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Zabihi, Zabiholah [Department of Physics, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Nayebi, Payman [Department of Physics, College of Technical and Engineering, Saveh Branch, Islamic Azad University, Saveh (Iran, Islamic Republic of); Ehsani, Mohammad Mahdi [Department of Physics, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of)

    2016-10-15

    II–VI semiconductor CdTe was grown on the Si(100) substrate surface by the ionized cluster beam (ICB) technique. In the ICB method, when vapors of solid materials such as CdTe were ejected through a nozzle of a heated crucible into a vacuum region, nanoclusters were created by an adiabatic expansion phenomenon. The clusters thus obtained were partially ionized by electron bombardment and then accelerated onto the silicon substrate at 473 K by high potentials. The cluster size was determined using a retarding field energy analyzer. The results of X-ray diffraction measurements indicate the cubic zinc blende (ZB) crystalline structure of the CdTe thin film on the silicon substrate. The CdTe thin film prepared by the ICB method had high crystalline quality. The microscopic processes involved in the ICB deposition technique, such as impact and coalescence processes, have been studied in detail by molecular dynamics (MD) simulation.

  3. The growth of III-V nitrides heterostructure on Si substrate by plasma-assisted molecular beam epitaxy

    International Nuclear Information System (INIS)

    Beh, K.P.; Yam, F.K.; Chin, C.W.; Tneh, S.S.; Hassan, Z.

    2010-01-01

    This paper reports the growth of InGaN/GaN/AlN epitaxial layer on Si(1 1 1) substrate by utilizing plasma-assisted molecular beam epitaxy (PA-MBE) system. The as-grown film was characterized using high-resolution X-ray diffraction (HR-XRD) and photoluminescence (PL). High work function metals, iridium and gold were deposited on the film as metal contacts and their electrical characteristics at pre- and post-annealing were studied. The structural quality of this film is comparative to the values reported in the literature, and the indium molar fraction is 0.57 by employing Vegard's law. The relatively low yellow band emission signifies the grown film is of high quality. For metal contact studies it was found that the post-annealed sample for 5 min shows good conductivity as compared to the other samples.

  4. Erosion behaviour of physically vapour-deposited and chemically vapour-deposited SiC films coated on molybdenum during oxygenated argon beam thinning

    International Nuclear Information System (INIS)

    Shikama, T.; Kitajima, M.; Fukutomi, M.; Okada, M.

    1984-01-01

    The erosion behaviour during bombardment with a 5 keV argon beam at room temperature was studied for silicon carbide (SiC) films of thickness of about 10 μm coated on molybdenum by physical vapour deposition (PVD) and chemical vapour deposition (CVD). The PVD SiC (plasma-assisted ion plating) exhibited a greater thinning rate than the CVD SiC film. Electron probe X-ray microanalysis revealed that the chemical composition of PVD SiC was changed to a composition enriched in silicon by the bombardment, and there was a notable change in its surface morphology. The CVD SiC retained its initial chemical composition with only a small change in its surface morphology. Auger electron spectroscopy indicated that silicon oxide was formed on the surface of PVD SiC by the bombardment. The greater thinning rate and easier change in chemical composition in PVD SiC could be attributed to its readier chemical reaction with oxygen due to its more non-uniform structure and weaker chemical bonding. Oxygen was present as one of the impurities in the argon beam. (Auth.)

  5. Measurement of strain and strain relaxation in free-standing Si membranes by convergent beam electron diffraction and finite element method

    Energy Technology Data Exchange (ETDEWEB)

    Gao, H., E-mail: hongye18@mm.kyushu-u.ac.jp [Faculty of Engineering Sciences, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan); Ikeda, K.; Hata, S.; Nakashima, H. [Faculty of Engineering Sciences, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan); Wang, D.; Nakashima, H. [Art, Science and Technology Center for Cooperative Research, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan)

    2011-04-15

    Bridge-shaped free-standing Si membranes (FSSM), strained by low-pressure (LP) Si{sub x}N{sub y}, plasma-enhanced (PE) Si{sub x}N{sub y} and Si{sub x}Ge{sub 1-x} stressors, were measured by convergent beam electron diffraction (CBED) and the finite element method (FEM). The results of CBED show that, while the strain along the length of the FSSM is compressive in an LPSi{sub x}N{sub y}/Si sample, those along the length of the FSSM are tensile in PESi{sub x}N{sub y}/Si and Si{sub x}Ge{sub 1-x}/Si samples. The average absolute values of strains are different in FSSM with LPSi{sub x}N{sub y}, PESi{sub x}N{sub y} and Si{sub x}Ge{sub 1-x} as stressors. The FEM was used to compensate the results of CBED taking into account the strain relaxation in transmission electron microscopy (TEM) sample preparation. The FEM results give the strain properties in three dimensions, and are in good agreement with the results of CBED. There is approximately no strain relaxation along the length of FSSM, and the elastic strains along the other two axes in FSSM are partially relaxed by thinning down for the preparation of TEM samples.

  6. Measurement of strain and strain relaxation in free-standing Si membranes by convergent beam electron diffraction and finite element method

    International Nuclear Information System (INIS)

    Gao, H.; Ikeda, K.; Hata, S.; Nakashima, H.; Wang, D.; Nakashima, H.

    2011-01-01

    Bridge-shaped free-standing Si membranes (FSSM), strained by low-pressure (LP) Si x N y , plasma-enhanced (PE) Si x N y and Si x Ge 1-x stressors, were measured by convergent beam electron diffraction (CBED) and the finite element method (FEM). The results of CBED show that, while the strain along the length of the FSSM is compressive in an LPSi x N y /Si sample, those along the length of the FSSM are tensile in PESi x N y /Si and Si x Ge 1-x /Si samples. The average absolute values of strains are different in FSSM with LPSi x N y , PESi x N y and Si x Ge 1-x as stressors. The FEM was used to compensate the results of CBED taking into account the strain relaxation in transmission electron microscopy (TEM) sample preparation. The FEM results give the strain properties in three dimensions, and are in good agreement with the results of CBED. There is approximately no strain relaxation along the length of FSSM, and the elastic strains along the other two axes in FSSM are partially relaxed by thinning down for the preparation of TEM samples.

  7. Study on the nanostructure formation mechanism of hypereutectic Al–17.5Si alloy induced by high current pulsed electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Bo, E-mail: gaob@smm.neu.edu.cn [School of Materials and Metallurgy, Northeastern University, Shenyang 110004 (China); Hu, Liang [School of Materials and Metallurgy, Northeastern University, Shenyang 110004 (China); Li, Shi-wei [School of Materials and Metallurgy, Northeastern University, Shenyang 110004 (China); Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093 (China); Hao, Yi [School of Materials and Metallurgy, Northeastern University, Shenyang 110004 (China); Zhang, Yu-dong [Laboratoire d’Etude des Textures et Applications aux Matériaux (LETAM, UMR-CNRS 7078), Université Paul Verlaine de Metz, Ile du Saulcy, Metz 57012 (France); Tu, Gan-feng [School of Materials and Metallurgy, Northeastern University, Shenyang 110004 (China); Grosdidier, Thierry [Laboratoire d’Etude des Textures et Applications aux Matériaux (LETAM, UMR-CNRS 7078), Université Paul Verlaine de Metz, Ile du Saulcy, Metz 57012 (France)

    2015-08-15

    This work investigates the nanostructure forming mechanism of hypereutectic Al–17.5Si alloy associated with the high current pulsed electron beam (HCPEB) treatment with increasing number of pulses by electron backscatter diffraction (EBSD) and SEM. The surface layers were melted and resolidified rapidly. The treated surfaces show different structural characteristics in different compositions and distribution zones. The top melted-layer zone can be divided into three zones: Si-rich, Ai-rich, and intermediate zone. The Al-rich zone has a nano-cellular microstructure with a diameter of ∼100 nm. The microstructure in the Si-rich zone consists of fine, dispersive, and spherical nano-sized Si crystals surrounded by α(Al) cells. Some superfine eutectic structures form in the boundary of the two zones. With the increase of number of pulses, the proportion of Si-rich zone to the whole top surface increases, and more cellular substructures are transformed to fine equiaxed grain. In other words, with increasing number of pulses, more Si elements diffuse to the Al-rich zone and provide heterogeneous nucleation sites, and Al grains are refined dramatically. Moreover, the relationship between the substrate Si phase and crystalline phase is determined by EBSD; that is, (1 1 1){sub Al}//(0 0 1){sub Si} with a value of disregistry δ at approximately 5%. The HCPEB technique is a versatile technique for refining the surface microstructure of hypereutectic Al–Si alloys.

  8. Development of a dc, broad beam, Mevva ion source

    International Nuclear Information System (INIS)

    Brown, I.G.; Dickinson, M.R.; Galvin, J.E.; MacGill, R.A.

    1991-09-01

    We are developing an embodiment of metal vapor vacuum arc (Mevva) ion source which will operate dc and have very large area beam. In preliminary testing, a dc titanium ion beam was formed with a current of approximately 0.6 amperes at an extraction voltage of 9kV (about 18 keV ion energy, by virtue of the ion charge state distribution) and using an 18 cm diameter set of multi-aperture. Separately, we have tested and formed beam from a 50 cm diameter (2000 cm 2 ) set of grids using a pulsed plasma gun. This configuration appears to be very efficient in terms of plasma utilization, and we have formed beams with diameter 33 cm (FWHM) and ion current up to 7 amperes at an extraction voltage of 50 kV (about 100 keV mean ion energy) and up to 20 amperes peak at the current overshoot part of the beam pulse. Here we describe this Part Of our Mevva development program and summarize the results obtained to-date

  9. In situ study of interface reactions of ion beam sputter deposited (Ba0.5Sr0.5)TiO3 films on Si, SiO2, and Ir

    International Nuclear Information System (INIS)

    Gao, Y.; Mueller, A.H.; Irene, E.A.; Auciello, O.; Krauss, A.; Schultz, J.A.

    1999-01-01

    (Ba 0.5 ,Sr 0.5 )TiO 3 (BST) thin films were deposited on MgO, Si, SiO 2 and Ir surfaces by ion beam sputter deposition in oxygen at 700 degree C. In situ spectroscopic ellipsometry (SE) has been used to investigate the evolution of the BST films on different surfaces during both deposition and postannealing processes. First, the optical constants of the BST films in the photon energy range of 1.5 - 4.5 eV were determined by SE analysis on crystallized BST films deposited on MgO single crystal substrates. The interfaces in BST/Si and BST/SiO 2 /Si structure were examined by SE and Auger electron spectroscopy depth profiles. Subcutaneous oxidation in the BST/Ir structure was observed by in situ SE during both ion beam sputter deposition and postdeposition annealing in oxygen at 700 degree C. A study of the thermal stability of the Ir/TiN/SiO 2 /Si structure in oxygen at 700 degree C was carried out using in situ SE. The oxidation of Ir was confirmed by x-ray diffraction. The surface composition and morphology evolution after oxidation were investigated by time of flight mass spectroscopy of recoiled ions (TOF-MSRI) and atomic force microscopy. It has been found that Ti from the underlying TiN barrier layer diffused through the Ir layer onto the surface and thereupon became oxidized. It was also shown that the surface roughness increases with increasing oxidation time. The implications of the instability of Ir/TiN/SiO 2 /Si structure on the performance of capacitor devices based on this substrate are discussed. It has been shown that a combination of in situ SE and TOF-MSRI provides a powerful methodology for in situ monitoring of complex oxide film growth and postannealing processes. copyright 1999 American Vacuum Society

  10. Xe ion beam induced rippled structures on differently oriented single-crystalline Si surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Hanisch, Antje; Grenzer, Joerg; Facsko, Stefan [Forschungszentrum Dresden-Rossendorf, Institut fuer Ionenstrahlphysik und Materialforschung, PO Box 510119, 01314 Dresden (Germany); Biermanns, Andreas; Pietsch, Ullrich, E-mail: A.Hanisch@fzd.d [Universitaet Siegen, Festkoerperphysik, 57068 Siegen (Germany)

    2010-03-24

    We report on Xe{sup +} induced ripple formation at medium energy on single-crystalline silicon surfaces of different orientations using substrates with an intentional miscut from the [0 0 1] direction and a [1 1 1] oriented wafer. The ion beam incidence angle with respect to the surface normal was kept fixed at 65{sup 0} and the ion beam projection was parallel or perpendicular to the [1 1 0] direction. By a combination of atomic force microscopy, x-ray diffraction and high-resolution transmission electron microscopy we found that the features of the surface and subsurface rippled structures such as ripple wavelength and amplitude and the degree of order do not depend on the surface orientation as assumed in recent models of pattern formation for semiconductor surfaces. (fast track communication)

  11. Electron beam and laser surface alloying of Al-Si base alloys

    International Nuclear Information System (INIS)

    Vanhille, P.; Tosto, S.; Pelletier, J.M.; Issa, A.; Vannes, A.B.; Criqui, B.

    1992-01-01

    Surface alloying on aluminium-base alloys is achieved either by using an electron beam or a laser beam, in order to improve the mechanical properties of the near-surface region. A predeposit of nickel is first realized by plasma spraying. Melting of both the coating and part of the substrate produces a surface alloy with a fine, dendritic microstructure with a high hardness. Enhancement of this property requires an increase in the nickel content. Various problems occur during the formation of nickel-rich surface layers: incomplete homogenization owing to a progressive increase of the liquidus temperature, cracks owing to the brittleness of this hard suface alloy, formation of a plasma when experiments are carried out in a gaseous environment (laser surface alloying). Nevertheless, various kinds of surface layers may be achieved; for example very hard surface alloys (HV 0.2 =900), with a thickness of about 500-600 μm, or very thick surface alloys (e>2 mm), with a fairly good hardness (greater than 350 HV 0.2 ). Thus, it is possible to obtain a large variety of new materials by using high energy beams on aluminium substrates. (orig.)

  12. Microstructure and mechanical properties of Al-Fe-V-Si aluminum alloy produced by electron beam melting

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Shaobo; Zheng, Lijing, E-mail: zhenglijing@buaa.edu.cn; Peng, Hui; Zhang, Hu

    2016-04-06

    Atomized, pre-alloyed Al-8.5Fe-1.3V-1.7Si (wt%) powder was used to fabricate solid components by electron beam melting (EBM). The residual porosity, chemical composition, microstructure and mechanical properties have been investigated. Results show that the relative density of as-built alloy under the optimized processing parameters was 98.2%. Compare to the initial alloy powder, the EBM parts demonstrated a restricted aluminum loss (~1 wt%) and a quite low oxygen pickup. The microstructure of the deposits was non-uniform. The fusion zone and heat affected zone exhibited a large number of fine spherical Al{sub 12}(Fe,V){sub 3}Si particles (30–110 nm) distributed uniformly in the α-Al matrix. Some coarser Fe- and V-riched rectangle-like Al{sub m}Fe phase (m=4.0–4.4) with 100–400 nm in size was precipitated in the melting boundary zone. The microhardness of the EBM samples was 153 HV in average. The average ultimate tensile strength (UTS) reached 438 MPa with the elongation of 12%. A ductile fracture mode of the tensile specimens was also revealed.

  13. Systematic investigations of low energy Ar ion beam sputtering of Si and Ag

    Energy Technology Data Exchange (ETDEWEB)

    Feder, R., E-mail: rene.feder@iom-leipzig.de [Leibniz-Institut für Oberflächenmodifizierung, Permoserstraße 15, 04318 Leipzig (Germany); Frost, F.; Neumann, H.; Bundesmann, C.; Rauschenbach, B. [Leibniz-Institut für Oberflächenmodifizierung, Permoserstraße 15, 04318 Leipzig (Germany)

    2013-12-15

    Ion beam sputter deposition (IBD) delivers some intrinsic features influencing the growing film properties, because ion properties and geometrical process conditions generate different energy and spatial distributions of the sputtered and scattered particles. Even though IBD has been used for decades, the full capabilities are not investigated systematically and specifically used yet. Therefore, a systematic and comprehensive analysis of the correlation between the properties of the ion beam, the generated secondary particles and backscattered ions and the deposited films needs to be done. A vacuum deposition chamber has been set up which allows ion beam sputtering of different targets under variation of geometrical parameters (ion incidence angle, position of substrates and analytics in respect to the target) and of ion beam parameters (ion species, ion energy) to perform a systematic and comprehensive analysis of the correlation between the properties of the ion beam, the properties of the sputtered and scattered particles, and the properties of the deposited films. A set of samples was prepared and characterized with respect to selected film properties, such as thickness and surface topography. The experiments indicate a systematic influence of the deposition parameters on the film properties as hypothesized before. Because of this influence, the energy distribution of secondary particles was measured using an energy-selective mass spectrometer. Among others, experiments revealed a high-energetic maximum for backscattered primary ions, which shifts with increasing emission angle to higher energies. Experimental data are compared with Monte Carlo simulations done with the well-known Transport and Range of Ions in Matter, Sputtering version (TRIM.SP) code [J.P. Biersack, W. Eckstein, Appl. Phys. A: Mater. Sci. Process. 34 (1984) 73]. The thicknesses of the films are in good agreement with those calculated from simulated particle fluxes. For the positions of the

  14. Medium-energy ion-beam simulation of the effect of ionizing radiation and displacement damage on SiO{sub 2}-based memristive nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Belov, Alexey; Mikhaylov, Alexey; Korolev, Dmitry; Guseinov, Davud; Gryaznov, Eugeny; Okulich, Eugenia; Sergeev, Victor; Antonov, Ivan; Kasatkin, Alexandr; Gorshkov, Oleg [Lobachevsky University, 23/3 Gagarin prospect, 603950 Nizhny Novgorod (Russian Federation); Tetelbaum, David, E-mail: tetelbaum@phys.unn.ru [Lobachevsky University, 23/3 Gagarin prospect, 603950 Nizhny Novgorod (Russian Federation); Kozlovski, Vitali [St. Petersburg State Polytechnic University, 29 Polytechnicheskaya street, 195251 St. Petersburg (Russian Federation)

    2016-07-15

    The principles of ion-beam simulation of the effect of fast (fission) neutrons and high-energy protons based on medium-energy ion irradiation have been developed for the Au/Zr/SiO{sub 2}/TiN/Ti capacitor-like memristive nanostructures demonstrating the repeatable resistive switching phenomenon. By using the Monte-Carlo approach, the irradiation fluences of H{sup +}, Si{sup +} and O{sup +} ions at the energy of 150 keV are determined that provide the ionization and displacement damage equivalent to the cases of space protons (15 MeV) and fission neutrons (1 MeV) irradiation. No significant change in the resistive switching parameters is observed under ion irradiation up to the fluences corresponding to the extreme fluence of 10{sup 17} cm{sup −2} of space protons or fission neutrons. The high-level radiation tolerance of the memristive nanostructures is experimentally confirmed with the application of 15 MeV proton irradiation and is interpreted as related to the local nature of conducting filaments and high concentration of the initial field-induced defects in oxide film.

  15. Low-energy positron beams - origins, developments and applications

    International Nuclear Information System (INIS)

    Beling, C.D.; Charlton, M.

    1987-01-01

    Over the last 15 years there have been rapid advances in the technology associated with low-energy positron beams. The origins of these advances, and some of the major developments, are discussed. Some applications from the diverse fields of surface physics, atomic scattering and positronium studies are highlighted. (author)

  16. Development of nanometer resolution C-Band radio frequency beam position monitors in the Final Focus Test Beam

    International Nuclear Information System (INIS)

    Slaton, T.; Mazaheri, G.

    1998-08-01

    Using a 47 GeV electron beam, the Final Focus Test Beam (FFTB) produces vertical spot sizes around 70 nm. These small beam sizes introduce an excellent opportunity to develop and test high resolution Radio Frequency Beam Position Monitors (RF-BPMs). These BPMs are designed to measure pulse to pulse beam motion (jitter) at a theoretical resolution of approximately 1 nm. The beam induces a TM 110 mode with an amplitude linearly proportional to its charge and displacement from the BPM's (cylindrical cavity) axis. The C-band (5,712 MHz) TM 110 signal is processed and converted into beam position for use by the Stanford Linear Collider (SLC) control system. Presented are the experimental procedures, acquisition, and analysis of data demonstrating resolution of jitter near 25 nm. With the design of future e + e - linear colliders requiring spot sizes close to 3 nm, understanding and developing RF-BPMs will be essential in resolving and controlling jitter

  17. Improving the growth of Ge/Si islands by modulating the spacing between screen and accelerator grids in ion beam sputtering deposition system

    International Nuclear Information System (INIS)

    Yang, Jie; Zhao, Bo; Wang, Chong; Qiu, Feng; Wang, Rongfei; Yang, Yu

    2016-01-01

    Highlights: • Ge islands were prepared by ion beam sputtering with different grid-to-grid gaps. • Ge islands with larger sizes and low density are observed in 1-mm-spaced samples. • The island growth was determined by sputter energy and the quality of Si buffer. • The crystalline volume fraction of buffer must be higher than 72% to grow islands. - Abstract: Ge islands were fabricated on Si buffer layer by ion beam sputtering deposition with a spacing between the screen and accelerator grids of either 1 mm or 2 mm. The Si buffer layer exhibits mixed-phase microcrystallinity for samples grown with 1 mm spacing and crystallinity for those with 2 mm spacing. Ge islands are larger and less dense than those grown on the crystalline buffer because of the selective growth mechanism on the microcrystalline buffer. Moreover, the nucleation site of Ge islands formed on the crystalline Si buffer is random. Ge islands grown at different grid-to-grid gaps are characterized by two key factors, namely, divergence half angle of ion beam and crystallinity of buffer layer. High grid-to-grid spacing results in small divergence half angle, thereby enhancing the sputtering energy and redistribution of sputtered atoms. The crystalline volume fraction of the microcrystalline Si buffer was obtained based on the integrated intensity ratio of Raman peaks. The islands show decreased density with decreasing crystalline volume fraction and are difficult to observe at crystalline volume fractions lower than 72%.

  18. Improving the growth of Ge/Si islands by modulating the spacing between screen and accelerator grids in ion beam sputtering deposition system

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jie; Zhao, Bo [Institute of Optoelectronic Information Materials, School of Materials Science and Engineering, Yunnan University, Kunming 650091 (China); Yunnan Key Laboratory for Micro/Nano Materials and Technology, Yunnan University, Kunming 650091 (China); Wang, Chong, E-mail: cwang@mail.sitp.ac.cn [Institute of Optoelectronic Information Materials, School of Materials Science and Engineering, Yunnan University, Kunming 650091 (China); Yunnan Key Laboratory for Micro/Nano Materials and Technology, Yunnan University, Kunming 650091 (China); Qiu, Feng; Wang, Rongfei [Institute of Optoelectronic Information Materials, School of Materials Science and Engineering, Yunnan University, Kunming 650091 (China); Yunnan Key Laboratory for Micro/Nano Materials and Technology, Yunnan University, Kunming 650091 (China); Yang, Yu, E-mail: yuyang@ynu.edu.cn [Institute of Optoelectronic Information Materials, School of Materials Science and Engineering, Yunnan University, Kunming 650091 (China); Yunnan Key Laboratory for Micro/Nano Materials and Technology, Yunnan University, Kunming 650091 (China)

    2016-11-15

    Highlights: • Ge islands were prepared by ion beam sputtering with different grid-to-grid gaps. • Ge islands with larger sizes and low density are observed in 1-mm-spaced samples. • The island growth was determined by sputter energy and the quality of Si buffer. • The crystalline volume fraction of buffer must be higher than 72% to grow islands. - Abstract: Ge islands were fabricated on Si buffer layer by ion beam sputtering deposition with a spacing between the screen and accelerator grids of either 1 mm or 2 mm. The Si buffer layer exhibits mixed-phase microcrystallinity for samples grown with 1 mm spacing and crystallinity for those with 2 mm spacing. Ge islands are larger and less dense than those grown on the crystalline buffer because of the selective growth mechanism on the microcrystalline buffer. Moreover, the nucleation site of Ge islands formed on the crystalline Si buffer is random. Ge islands grown at different grid-to-grid gaps are characterized by two key factors, namely, divergence half angle of ion beam and crystallinity of buffer layer. High grid-to-grid spacing results in small divergence half angle, thereby enhancing the sputtering energy and redistribution of sputtered atoms. The crystalline volume fraction of the microcrystalline Si buffer was obtained based on the integrated intensity ratio of Raman peaks. The islands show decreased density with decreasing crystalline volume fraction and are difficult to observe at crystalline volume fractions lower than 72%.

  19. Present and future radioactive nuclear beam developments at Argonne

    International Nuclear Information System (INIS)

    Decrock, P.

    1996-01-01

    A scheme for building an ISOL-based radioactive nuclear beam facility at the Argonne Physics Division, is currently evaluated. The feasibility and efficiency of the different steps in the proposed production- and acceleration cycles are being tested. At the Dynamitron Facility of the ANL Physics Division, stripping yields of Kr, Xe and Ph beams in a windowless gas cell have been measured and the study of fission of 238 U induced by fast neutrons from the 9 Be(dn) reaction is in progress. Different aspects of the post-acceleration procedure are currently being investigated. In parallel with this work, energetic radioactive beams such as 17 F, 18 F and 56 Ni have recently been developed at Argonne using the present ATLAS facility

  20. The development of enabling technologies for producing active interrogation beams.

    Science.gov (United States)

    Kwan, Thomas J T; Morgado, Richard E; Wang, Tai-Sen F; Vodolaga, B; Terekhin, V; Onischenko, L M; Vorozhtsov, S B; Samsonov, E V; Vorozhtsov, A S; Alenitsky, Yu G; Perpelkin, E E; Glazov, A A; Novikov, D L; Parkhomchuk, V; Reva, V; Vostrikov, V; Mashinin, V A; Fedotov, S N; Minayev, S A

    2010-10-01

    A U.S./Russian collaboration of accelerator scientists was directed to the development of high averaged-current (∼1 mA) and high-quality (emittance ∼15 πmm mrad; energy spread ∼0.1%) 1.75 MeV proton beams to produce active interrogation beams that could be applied to counterterrorism. Several accelerator technologies were investigated. These included an electrostatic tandem accelerator of novel design, a compact cyclotron, and a storage ring with energy compensation and electron cooling. Production targets capable of withstanding the beam power levels were designed, fabricated, and tested. The cyclotron/storage-ring system was theoretically studied and computationally designed, and the electrostatic vacuum tandem accelerator at BINP was demonstrated for its potential in active interrogation of explosives and special nuclear materials.

  1. Diagnostics development for E-beam excited air channels

    Science.gov (United States)

    Eckstrom, D. J.; Dickenson, J. S.

    1982-02-01

    As the tempo of development of particle beam weapons increases, more detailed diagnostics of the interaction of the particle beam with the atmosphere are being proposed and implemented. Some of these diagnostics involve probing of the excited air channel with visible wavelength laser radiation. Examples include the use of visible wavelength interferometry to measure electron density profiles in the nose of the beam Ri81 and Stark shift measurements to determine self-induced electric fields Hi81, DR81. In these diagnostics, the change in laser intensity due to the desired diagnostic effect can be quite small, leading to the possibility that other effects, such as gas phase absorption, could seriously interfere with the measurement.

  2. New development for low energy electron beam processor

    International Nuclear Information System (INIS)

    Takei, Taro; Goto, Hitoshi; Oizumi, Matsutoshi; Hirakawa, Tetsuya; Ochi, Masafumi

    2003-01-01

    Newly developed low-energy electron beam (EB) processors that have unique designs and configurations compared to conventional ones enable electron-beam treatment of small three-dimensional objects, such as grain-like agricultural products and small plastic parts. As the EB processor can irradiate the products from the whole angles, the uniform EB treatment can be achieved at one time regardless the complex shapes of the product. Here presented are two new EB processors: the first system has cylindrical process zone, which allows three-dimensional objects to be irradiated with one-pass treatment. The second is a tube-type small EB processor, achieving not only its compactor design, but also higher beam extraction efficiency and flexible installation of the irradiation heads. The basic design of each processor and potential applications with them will be presented in this paper. (author)

  3. Pulsed Cs beam development for the BNL polarized H- source

    International Nuclear Information System (INIS)

    Alessi, J.G.

    1983-01-01

    A pulsed Cs + beam has been developed for use on a polarized H - source. Cesium ion production is by surface ionization using a porous tungsten ionizer. While satisfactory current pulses (5 to 10 mA greater than or equal to 0.5 ms) can be obtained, the pulse shapes are a sensitive function of the ionizer temperature and Cs surface coverage. The beam optical requirements are stringent, and the optics have been studied experimentally for both Cs + and Cs 0 beams. Computer calculations are in good agreement with the observed results. The present source has delivered 2.6 mA of Cs + through the interaction region of the polarized ion source, and as much as 2.0 particle mA of Cs 0 . A new source is being built which is designed to give 15 mA through the interaction region

  4. An EUDET/AIDA Pixel Beam Telescope for Detector Development

    CERN Document Server

    Rubinskiy, I

    2015-01-01

    Ahigh resolution(σ< 2 μm) beam telescope based on monolithic active pixel sensors (MAPS) was developed within the EUDET collaboration. EUDET was a coordinated detector R&D programme for the future International Linear Collider providing test beam infrastructure to detector R&D groups. The telescope consists of six sensor planes with a pixel pitch of either 18.4 μm or 10 μmand canbe operated insidea solenoidal magnetic fieldofupto1.2T.Ageneral purpose cooling, positioning, data acquisition (DAQ) and offine data analysis tools are available for the users. The excellent resolution, readout rate andDAQintegration capabilities made the telescopea primary beam tests tool also for several CERN based experiments. In this report the performance of the final telescope is presented. The plans for an even more flexible telescope with three differentpixel technologies(ATLASPixel, Mimosa,Timepix) withinthenew European detector infrastructure project AIDA are presented.

  5. Development of high temperature resistant ceramic matrix composites based on SiC- and novel SiBNC-fibres

    International Nuclear Information System (INIS)

    Daenicke, Enrico

    2014-01-01

    Novel ceramic fibres in the quaternary system Si-B-C-N exhibit excellent high temperature stability and creep resistance. In th is work it was investigated, to what extent these outstanding properties of SiBNC-fibres can be transferred into ceramic matrix composites (CMC) in comparison to commercial silicon carbide (SiC) fibres. For the CMC development the liquid silicon infiltration (LSI) as well as the polymer infiltration and pyrolysis process (PIP) was applied. Extensive correlations between fibre properties, fibre coating (without, pyrolytic carbon, lanthanum phosphate), process parameters of the CMC manufacturing method and the mechanical and microstructural properties of the CMC before and after exposure to air could be established. Hence, the potential of novel CMCs can be assessed and application fields can be derived.

  6. Control over the morphology of AlN during molecular beam epitaxy with the plasma activation of nitrogen on Si (111) substrates

    International Nuclear Information System (INIS)

    Mizerov, A. M.; Kladko, P. N.; Nikitina, E. V.; Egorov, A. Yu.

    2015-01-01

    The results of studies of the growth kinetics of AlN layers during molecular beam epitaxy with the plasma activation of nitrogen using Si (111) substrates are presented. The possibility of the growth of individual AlN/Si (111) nanocolumns using growth conditions with enrichment of the surface with metal near the formation mode of Al drops, at a substrate temperature close to maximal, during molecular beam epitaxy with the plasma activation of nitrogen (T s ≈ 850°C) is shown. The possibility of growing smooth AlN layers on a nanocolumnar AlN/Si (111) buffer with the use of T s ≈ 750°C and growth conditions providing enrichment with metal is shown

  7. Control over the morphology of AlN during molecular beam epitaxy with the plasma activation of nitrogen on Si (111) substrates

    Energy Technology Data Exchange (ETDEWEB)

    Mizerov, A. M., E-mail: mizerov@beam.ioffe.ru; Kladko, P. N.; Nikitina, E. V.; Egorov, A. Yu. [Russian Academy of Sciences, St. Petersburg Academic University-Nanotechnology Research and Education Centre (Russian Federation)

    2015-02-15

    The results of studies of the growth kinetics of AlN layers during molecular beam epitaxy with the plasma activation of nitrogen using Si (111) substrates are presented. The possibility of the growth of individual AlN/Si (111) nanocolumns using growth conditions with enrichment of the surface with metal near the formation mode of Al drops, at a substrate temperature close to maximal, during molecular beam epitaxy with the plasma activation of nitrogen (T{sub s} ≈ 850°C) is shown. The possibility of growing smooth AlN layers on a nanocolumnar AlN/Si (111) buffer with the use of T{sub s} ≈ 750°C and growth conditions providing enrichment with metal is shown.

  8. Si(001):B gas-source molecular-beam epitaxy: Boron surface segregation and its effect on film growth kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Kim, H.; Glass, G.; Spila, T.; Taylor, N.; Park, S.Y.; Abelson, J.R.; Greene, J.E. [Department of Materials Science, Coordinated Science Laboratory, and Materials Research Laboratory, University of Illinois, 1101 West Springfield, Urbana, Illinois 61801 (United States)

    1997-09-01

    B-doped Si(001) films, with concentrations C{sub B} up to 1.7{times}10{sup 22}cm{sup {minus}3}, were grown by gas-source molecular-beam epitaxy from Si{sub 2}H{sub 6} and B{sub 2}H{sub 6} at T{sub s}=500{endash}800{degree}C. D{sub 2} temperature-programed desorption (TPD) spectra were then used to determine B coverages {theta}{sub B} as a function of C{sub B} and T{sub s}. In these measurements, as-deposited films were flash heated to desorb surface hydrogen, cooled, and exposed to atomic deuterium until saturation coverage. Strong B surface segregation was observed with surface-to-bulk B concentration ratios ranging up to 1200. TPD spectra exhibited {beta}{sub 2} and {beta}{sub 1} peaks associated with dideuteride and monodeuteride desorption as well as lower-temperature B-induced peaks {beta}{sub 2}{sup {asterisk}} and {beta}{sub 1}{sup {asterisk}}. Increasing {theta}{sub B} increased the area under {beta}{sub 2}{sup {asterisk}} and {beta}{sub 1}{sup {asterisk}} at the expense of {beta}{sub 2} and {beta}{sub 1} and decreased the total D coverage {theta}{sub D}. The TPD results were used to determine the B segregation enthalpy, {minus}0.53eV, and to explain and model the effects of high B coverages on Si(001) growth kinetics. Film deposition rates R increase by {ge}50{percent} with increasing C{sub B}{tilde {gt}}1{times}10{sup 19}cm{sup {minus}3} at T{sub s}{le}550{degree}C, due primarily to increased H desorption rates from B-backbonded Si adatoms, and decrease by corresponding amounts at T{sub s}{ge}600{degree}C due to decreased adsorption site densities. At T{sub s}{ge}700{degree}C, high B coverages also induce {l_brace}113{r_brace} facetting. {copyright} {ital 1997 American Institute of Physics.}

  9. Development of III-V/Si Multijunction Space Photovoltaics

    Data.gov (United States)

    National Aeronautics and Space Administration — High substrate costs, as well as weight, typically play a major role in the high costs of multijunction space solar cell production and deployment. III-V/Si...

  10. Development of a polarized neutron beam line at Algerian research reactors using McStas software

    Science.gov (United States)

    Makhloufi, M.; Salah, H.

    2017-02-01

    Unpolarized instrumentation has long been studied and designed using McStas simulation tool. But, only recently new models were developed for McStas to simulate polarized neutron scattering instruments. In the present contribution, we used McStas software to design a polarized neutron beam line, taking advantage of the available spectrometers reflectometer and diffractometer in Algeria. Both thermal and cold neutron was considered. The polarization was made by two types of supermirrors polarizers FeSi and CoCu provided by the HZB institute. For sake of performance and comparison, the polarizers were characterized and their characteristics reproduced. The simulated instruments are reported. Flipper and electromagnets for guide field are developed. Further developments including analyzers and upgrading of the existing spectrometers are underway.

  11. Analysis of the crystalline characteristics of nc-Si:H thin film using a hyperthermal neutral beam generated by an inclined slot-excited antenna

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong-Bae; Kim, Young-Woo; Kim, Dae Chul; Kim, Jongsik; Hong, Seung Pyo; Yoo, Suk Jae; Oh, Kyoung Suk, E-mail: ksoh@nfri.re.kr

    2013-11-29

    The deposition of hydrogenated nano-crystal silicon (nc-Si:H) thin film for manufacturing quantum dot solar cells, which has received attention due to the use of this film third-generation solar cells, is studied here. A hyperthermal neutral beam (HNB) generated by an inclined slot-excited antenna plasma source is used to reduce damage to the silicon thin film and deposition of the crystalline thin film is carried out on a substrate at a low temperature (< 200 °C). The size and the crystalline fraction of the nc-Si:H of the deposited thin film were analyzed by scanning transmission electron microscopy and a Raman microscope. As a result, silicon crystals 1–10 nm in size were observed in the amorphous silicon matrix. According to previous studies, the size and the crystalline fraction of nc-Si:H in deposited thin films increase as the hydrogen flow rate is increased. However, the increment of hydrogen flow rate decreases the deposition rate rapidly. The size and the crystalline fraction of nc-Si:H are adjustable by varying the substrate temperature and HNB energy without a change of the hydrogen flow rate. There are optimum conditions between the HNB energy and the substrate temperature for an appropriate amount of nc-Si:H in silicon thin film. - Highlights: • The appropriate hyperthermal neutral beam energy seems to assist film formation. • The Si crystal size can be adjusted by varying hyperthermal neutral beam energy. • The nc-Si:H 1 ∼ 10 in nm size was observed in the amorphous silicon matrix.

  12. Development of KOMAC Beam Monitoring System Using EPICS

    Energy Technology Data Exchange (ETDEWEB)

    Song, Young-Gi; Yun, Sang-Pil; Kim, Han-Sung; Kwon, Hyeok-Jung; Cho, Yong-Sub [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    The beam loss signals must be digitized and the sampling has to be synchronized to a reference signal which is an external trigger for beam operation. The digitized data must be accessible by the Experimental Physics and Industrial Control System (EPICS)-based control system, which manages the whole accelerator control. In order to satisfy the requirement, an Input /Output Controller (IOC), which runs Linux on a CPU module with PCI express based Analog to Digital Converter (ADC) modules, has been adopted. An associated linux driver and EPICS device support module also have been developed. The IOC meets the requirements and the development and maintenance of the software for the IOC is considerably efficient. The data acquisition system running EPICS will be used in increasing phase of KOrea Multi-purpose Accelerator Complex (KOMAC) beam power. The beam monitoring system integrates BLM and BPM signals into control system and offers real-time data to operators. The IOC, which is implemented with Linux and PCI driver, has supported data acquisition as a very flexible solution.

  13. BNL neutral beam development group. Progress report FY 1980

    International Nuclear Information System (INIS)

    Prelec, K.; Sluyters, T.

    1981-01-01

    The objective of the BNL Neutral Beam Program is to develop a 250 keV neutral beam system suitable for heating and other experiments in toroidal or mirror plasma devices. The system is based on acceleration and neutralization of negative hydrogen ions produced in and directly extracted from a source. The objective of source studies is to develop a module delivering 10 A of negative ion currents, with pulse lengths ranging from several seconds duration up to a steady-state operation. The extracted current density should be several hundred mA/cm 2 , and the source should operate with power and gas efficiencies acceptable from the beam line point of view. The objective of beam extraction and transport studies is to design a system matching the 10 A source module to the acceleration stage. The 250 keV acceleration studies cover several options, including a d.c. close-coupled system, a large aperture d.c. system matched to the source by a bending magnet, a multiaperture d.c. system following a multiaperture strong focusing transport line, and a MEQALAC structure

  14. Development of KOMAC Beam Monitoring System Using EPICS

    International Nuclear Information System (INIS)

    Song, Young-Gi; Yun, Sang-Pil; Kim, Han-Sung; Kwon, Hyeok-Jung; Cho, Yong-Sub

    2014-01-01

    The beam loss signals must be digitized and the sampling has to be synchronized to a reference signal which is an external trigger for beam operation. The digitized data must be accessible by the Experimental Physics and Industrial Control System (EPICS)-based control system, which manages the whole accelerator control. In order to satisfy the requirement, an Input /Output Controller (IOC), which runs Linux on a CPU module with PCI express based Analog to Digital Converter (ADC) modules, has been adopted. An associated linux driver and EPICS device support module also have been developed. The IOC meets the requirements and the development and maintenance of the software for the IOC is considerably efficient. The data acquisition system running EPICS will be used in increasing phase of KOrea Multi-purpose Accelerator Complex (KOMAC) beam power. The beam monitoring system integrates BLM and BPM signals into control system and offers real-time data to operators. The IOC, which is implemented with Linux and PCI driver, has supported data acquisition as a very flexible solution

  15. Initial oxidation processes of Si(001) surfaces by supersonic O2 molecular beams. Different oxidation mechanisms for clean and partially-oxidized surfaces

    International Nuclear Information System (INIS)

    Teraoka, Yuden; Yoshigoe, Akitaka

    2002-01-01

    Potential energy barriers for dissociative chemisorption of O 2 molecules on Si(001) clean surfaces were investigated using supersonic O 2 molecular beams and photoemission spectroscopy. Relative initial sticking probabilities of O 2 molecules and the saturated oxygen amount on the Si(001) surface were measured as a function of incident energy of O 2 molecules. Although the probability was independent on the incident energy in the region larger than 1 eV, the saturated oxygen amount was dependent on the incident energy without energy thresholds. An Si-2p photoemission spectrum of the Si(001) surface oxidized by thermal O 2 gas revealed the oxygen insertion into dimer backbond sites. These facts indicate that a reaction path of the oxygen insertion into dimer backbonds through bridge sites is open for the clean surface oxidation, and the direct chemisorption probability at the backbonds is negligibly small comparing with that at the bridge sites. (author)

  16. Effect of oxygen on the processes of ion beam synthesis of buried SiC layers in silicon

    International Nuclear Information System (INIS)

    Artamonov, V.V.; Valakh, M.Ya.; Klyuj, N.I.; Mel'nik, V.P.; Romanyuk, A.B.; Romanyuk, B.N.; Yukhimchuk, V.A.

    1998-01-01

    The properties of Si-structures with buried silicon carbide (SiC) layers created by high dose carbon implantation into Cz-Si or Fz-Si wafers followed by high-temperature annealing were studied by Raman and infrared spectroscopy. Effect of additional oxygen implantation on the peculiarities of SiC layer formation was also studied. It was shown that under the same implantation and post-implantation annealing conditions the buried SiC layers are more effectively formed in Cz-Si or in Si subjected to additional oxygen implantation. Thus, oxygen in silicon promotes the SiC layer formation due to SiO x precipitate creation and accommodation of the crystal volume in the region where SiC phase is formed

  17. Investigation of electric fields in B-implanted Si by positron beam spectroscopy

    International Nuclear Information System (INIS)

    Abdulmalik, D.A.; Coleman, P.G.

    2007-01-01

    Besides its conventional applications in defect characterization, variable-energy positron annihilation spectroscopy can be employed to monitor internal electric fields in the depletion regions in semiconductor structures. In this work, electric fields were studied in pre-amorphized Cz Si wafers (background dopant level ∝10 15 cm -3 ) implanted with 0.5 keV B ions at a dose of 10 15 cm -2 , and then annealed isothermally at 800 C for times ranging from 1 to 2700 s. Differences in the S parameter with annealing time were observed in samples implanted (a) with B ions only and (b) with B followed by F ions at 10 keV; these were attributed to different electric fields, which drift positrons back (a) to the surface, or (b) to a vacancy-like defected layer. Fitting of the data revealed depletion regions of widths between 150-350 nm centered at depths between 250-350 nm, with electric field values in the range -9 x 10 6 to -3 x 10 6 Vm -1 . The depth and width of the depletion regions increase significantly for annealing times greater than 100 s, attributed to B diffusion. The results are consistent with simple theoretical estimates, but the uncertainties on the latter are large. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Ion beam effects on the surface and near-surface composition of TaSi2

    International Nuclear Information System (INIS)

    Valeri, S.; Di Bona, A.; Ottaviani, G.; Procop, M.

    1991-01-01

    Low-energy (0.7-4.5 keV) ion bombardment effects on polycrystalline TaSi 2 at sputter steady state and in various intermediate steps have been investigated, in the temperature range up to 550degC, to determine the time and temperature dependence of the altered layer formation. This in turn enables a better knowledge of the synergistic effects of the processes mentioned above. At low temperatures (T≤410degC) the surface is silicon depleted, and the depletion is even more severe in the subsurface region up to a depth of several tens of angstroems; silicon preferential sputtering and radiation-enhanced segregation assisted by the displacement mixing-induced motion of atoms are assumed to be responsible for this composition profile, while thermally activated diffusion processes become operative above 410degC, reducing progressively the concentration gradient between the surface and the subsurface zone. The composition at different depths has been determined from Auger peaks for different kinetic energies, by varying the take-off angle and finally by sputter profiling at low in energy the high energy processed surfaces. Quantitative analysis has been performed by XPS and AES by using the elemental standard method. (orig.)

  19. An EUDET/AIDA Pixel Beam Telescope for Detector Development

    CERN Document Server

    Perrey, Hanno

    2013-01-01

    A high resolution ($\\sigma 2 \\sim \\mu$) beam telescope based on monolithic active pixel sensors (MAPS) was developed within the EUDET collaboration. The telescope consists of six sensor planes using Mimosa26 MAPS with a pixel pitch of $18.4 \\mu$ and thinned down to $50 \\mu$. The excellent resolution, readout rate and DAQ integration capabilities made the telescope a primary test beam tool for many groups including several CERN based experiments. Within the new European detector infrastructure project AIDA the test beam telescope will be further extended in terms of cooling infrastructure, readout speed and precision. In order to provide a system optimized for the different requirements by the user community, a combination of various pixel technologies is foreseen. In this report the design of this even more flexible telescope with three different pixel technologies (TimePix, Mimosa, ATLAS FE-I4) will be presented. First test beam results with the HitOR signal provided by the FE-I4 integrated into the trigger...

  20. Development of stereotactic radiosurgery using carbon beams (carbon-knife)

    Science.gov (United States)

    Keawsamur, Mintra; Matsumura, Akihiko; Souda, Hikaru; Kano, Yosuke; Torikoshi, Masami; Nakano, Takashi; Kanai, Tatsuaki

    2018-02-01

    The aim of this research is to develop a stereotactic-radiosurgery (SRS) technique using carbon beams to treat small intracranial lesions; we call this device the carbon knife. A 2D-scanning method is adapted to broaden a pencil beam to an appropriate size for an irradiation field. A Mitsubishi slow extraction using third order resonance through a rf acceleration system stabilized by a feed-forward scanning beam using steering magnets with a 290 MeV/u initial beam energy was used for this purpose. Ridge filters for spread-out Bragg peaks (SOBPs) with widths of 5 mm, 7.5 mm, and 10 mm were designed to include fluence-attenuation effects. The collimator, which defines field shape, was used to reduce the lateral penumbra. The lateral-penumbra width at the SOBP region was less than 2 mm for the carbon knife. The penumbras behaved almost the same when changing the air gap, but on the other hand, increasing the range-shifter thickness mostly broadened the lateral penumbra. The physical-dose rates were approximate 6 Gy s-1 and 4.5 Gy s-1 for the 10  ×  10 mm2 and 5  ×  5 mm2 collimators, respectively.

  1. Development and cytotoxicity evaluation of SiAlONs ceramics

    International Nuclear Information System (INIS)

    Santos, C.; Ribeiro, S.; Daguano, J.K.M.F.; Rogero, S.O.; Strecker, K.; Silva, C.R.M.

    2007-01-01

    SiAlONs are ceramics with high potential as biomaterials due to their chemical stability, associated with suitable mechanical properties, such as high fracture toughness and fracture resistance. The objective of this work was to investigate the mechanical properties and the cytotoxicity of these ceramic materials. Three different compositions were prepared, using silicon nitride, aluminum nitride and a rare earth oxide mixture as starting powders, yielding Si 3 N 4 -SiAlON composites or pure SiAlON ceramics, after hot-pressing at 1750 deg. C, for 30 min. The sintered samples were characterized by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). Furthermore, hardness and fracture toughness were determined using the Vicker's indentation method. The biological compatibility was evaluated by in vitro cytotoxicity tests. Ceramic with elevated hardness, ranging between 17 and 21 GPa, and high fracture toughness of 5 to 6 MPa m 1/2 were obtained. Since a nontoxic behavior was observed in the cytotoxicity tests, it may be assumed that SiAlON-based ceramics are viable materials for clinical applications

  2. Depth profile investigation of the incorporated iron atoms during Kr{sup +} ion beam sputtering on Si (001)

    Energy Technology Data Exchange (ETDEWEB)

    Khanbabaee, B., E-mail: khanbabaee@physik.uni-siegen.de [Solid State Physics, University of Siegen, D-57068 Siegen (Germany); Arezki, B.; Biermanns, A. [Solid State Physics, University of Siegen, D-57068 Siegen (Germany); Cornejo, M.; Hirsch, D. [Leibniz-Institut für Oberflächenmodifizierung e. V. (IOM), Permoserstraße 15, D-04318 Leipzig (Germany); Lützenkirchen-Hecht, D. [Abteilung Physik, Bergische Universität Wuppertal, D-42097 Wuppertal (Germany); Frost, F. [Leibniz-Institut für Oberflächenmodifizierung e. V. (IOM), Permoserstraße 15, D-04318 Leipzig (Germany); Pietsch, U. [Solid State Physics, University of Siegen, D-57068 Siegen (Germany)

    2013-01-01

    We investigate the incorporation of iron atoms during nano-patterning of Si surfaces induced by 2 keV Kr{sup +} ion beam erosion under an off-normal incidence angle of 15°. Considering the low penetration depth of the ions, we have used X-ray reflectivity (XRR) and X-ray absorption near edge spectroscopy (XANES) under grazing-incidence angles in order to determine the depth profile and phase composition of the incorporated iron atoms in the near surface region, complemented by secondary ion mass spectrometry and atomic force microscopy. XRR analysis shows the accumulation of metallic atoms within a near surface layer of a few nanometer thickness. We verify that surface pattern formation takes place only when the co-sputtered Fe concentration exceeds a certain limit. For high Fe concentration, the ripple formation is accompanied by the enhancement of Fe close to the surface, whereas no Fe enhancement is found for low Fe concentration at samples with smooth surfaces. Modeling of the measured XANES spectra reveals the appearance of different silicide phases with decreasing Fe content from the top towards the volume. - Highlights: ► We investigate the incorporation of iron atoms during nano-patterning of Si surfaces. ► Pattern formation occurs when the areal density of Fe exceeds a certain threshold. ► X-ray reflectivity shows a layering at near surface due to incorporated Fe atoms. ► It is shown that the patterning is accompanied with the appearance of Fe-rich silicide.

  3. Ion-beam mixed ultra-thin cobalt suicide (CoSi2) films by cobalt sputtering and rapid thermal annealing

    Science.gov (United States)

    Kal, S.; Kasko, I.; Ryssel, H.

    1995-10-01

    The influence of ion-beam mixing on ultra-thin cobalt silicide (CoSi2) formation was investigated by characterizing the ion-beam mixed and unmixed CoSi2 films. A Ge+ ion-implantation through the Co film prior to silicidation causes an interface mixing of the cobalt film with the silicon substrate and results in improved silicide-to-silicon interface roughness. Rapid thermal annealing was used to form Ge+ ion mixed and unmixed thin CoSi2 layer from 10 nm sputter deposited Co film. The silicide films were characterized by secondary neutral mass spectroscopy, x-ray diffraction, tunneling electron microscopy (TEM), Rutherford backscattering, and sheet resistance measurements. The experi-mental results indicate that the final rapid thermal annealing temperature should not exceed 800°C for thin (micrographs of the ion-beam mixed and unmixed CoSi2 films reveals that Ge+ ion mixing (45 keV, 1 × 1015 cm-2) produces homogeneous silicide with smooth silicide-to-silicon interface.

  4. Pulsed ion-beam assisted deposition of Ge nanocrystals on SiO{sub 2} for non-volatile memory device

    Energy Technology Data Exchange (ETDEWEB)

    Stepina, N.P. [Institute of Semiconductor Physics, Lavrenteva 13, 630090 Novosibirsk (Russian Federation)], E-mail: nstepina@mail.ru; Dvurechenskii, A.V.; Armbrister, V.A.; Kirienko, V.V.; Novikov, P.L.; Kesler, V.G.; Gutakovskii, A.K.; Smagina, Z.V.; Spesivtzev, E.V. [Institute of Semiconductor Physics, Lavrenteva 13, 630090 Novosibirsk (Russian Federation)

    2008-11-03

    A floating gate memory structure, utilizing Ge nanocrystals (NCs) deposited on tunnel SiO{sub 2}, have been fabricated using pulsed low energy ion-beam induced molecular-beam deposition (MBD) in ultra-high vacuum. The ion-beam action is shown to stimulate the nucleation of Ge NCs when being applied after thin Ge layer deposition. Growth conditions for independent change of NCs size and array density were established allowing to optimize the structure parameters required for memory device. Activation energy E = 0.25 eV was determined from the temperature dependence of NCs array density. Monte Carlo simulation has shown that the process, determining NCs array density, is the surface diffusion. Embedding of the crystalline Ge dots into silicon oxide was carried out by selective oxidation of Si(100)/SiO{sub 2} /Ge(NCs)/poly-Si structure. MOS-capacitor obtained after oxidation showed a hysteresis in its C-V curves attributed to charge retention in the Ge dots.

  5. Development of ion beam sputtering techniques for actinide target preparation

    International Nuclear Information System (INIS)

    Aaron, W.S.; Zevenbergen, L.A.; Adair, H.L.

    1985-01-01

    Ion beam sputtering is a routine method for the preparation of thin films used as targets because it allows the use of minimum quantity of starting material, and losses are much lower than most other vacuum deposition techniques. Work is underway in the Isotope Research Materials Laboratory (IRML) at ORNL to develop the techniques that will make the preparation of actinide targets up to 100 μg/cm 2 by ion beam sputtering a routinely available service from IRML. The preparation of the actinide material in a form suitable for sputtering is a key to this technique, as is designing a sputtering system that allows the flexibility required for custom-ordered target production. At present, development work is being conducted on low-activity in a bench-top system. The system will then be installed in a hood or glove box approved for radioactive materials handling where processing of radium, actinium, and plutonium isotopes among others will be performed. (orig.)

  6. Development of a nuclear data base for relativistic ion beams

    International Nuclear Information System (INIS)

    Townsend, L.W.; Wong, M.; Schimmerling, W.; Wilson, J.W.

    1987-01-01

    The primary limitation on the development of heavy ion beam transport methods is the lack of an accurate nuclear data base. Because of the large number of ion/target combinations, the complexity of the reaction products, and the broad range of energies required, it is unlikely that the data base will ever be compiled from experiments alone. For the last 15 years, relativistic heavy-ion accelerators have been available, but the experimental data base remains inadequate. However, theoretical models of heavy-ion reactions are being derived to provide cross section data for beam transport problems. A concurrent experimental program to provide sufficient experimental data to validate the model is also in progress. Model development and experimental results for model validation are discussed. The need for additional nuclear fragmentation data is identified

  7. Development of the ion source for PDX neutral beam injection

    International Nuclear Information System (INIS)

    Menon, M.M.; Tsai, C.C.; Gardner, W.L.; Barber, G.C.; Haselton, H.H.; Ponte, N.S.; Ryan, P.M.; Schechter, D.E.; Stirling, W.L.; Whealton, J.H.

    1979-01-01

    The paper describes the development of the ion source for neutral beam injection heating of PDX plasma. After a brief description of the plasma generator, the performance characteristics of the source, with different types of grids, are described. Based on test stand results it is concluded that at least two different versions of the source should be able to meet and even exceed the neutral power and energy requirements expected out of PDX injectors

  8. Non-equilibrium surface conditions and microstructural changes following pulsed laser irradiation and ion beam mixing of Ni overlayers on sintered alpha-SiC

    International Nuclear Information System (INIS)

    More, K.L.; Davis, R.F.

    1986-01-01

    Pulsed laser irradiation and ion beam mixing of thin Ni overlayers on sintered alpha-SiC have been investigated as potential surface modification techniques for the enhancement of the mechanical properties of the SiC. Each of these surface processing methods are nonequilibrium techniques; materials interactions can be induced at the specimen surface which are not possible with conventional thermal techniques. As a result of the surface modification, the physical properties of the ceramic can be altered under the correct processing conditions. Following laser irradiation using a pulsed ruby or krypton fluoride (KrF) excimer laser, the fracture strength of the SiC was increased by approximately 50 percent and 20 percent, respectively. However, ion-beam mixing of Ni on SiC resulted in no change in fracture strength. Cross-sectional transmission electron microscopy, scanning electron microscopy, secondary ion mass spectroscopy, and Rutherford backscattering techniques, have been used to characterize the extent of mixing between the Ni and SiC as a result of the surface modification and to determine the reason(s) for the observed changes in fracture strength. 19 references

  9. Development of ion beam sputtering technology for mold and die

    International Nuclear Information System (INIS)

    Lee, Jaehyung; Park, J.; Lee, J.; Jil, J.; Yang, D.; Noh, Y.; You, B.; You, J.

    2003-06-01

    Ion beam sputtering technique, one of the surface modification techniques, is to reduce surface roughness of materials with selective detaching atoms and micro particles from the surface by bombarding energetic ions of a few to a few tens keV onto the materials surfaces. This technique can be applied for the surfaces that need to have sub micrometer surface roughness, and it has already been used by companies and/or Institute over the world. Although this is relatively high cost process, it has been widely demanded in the industries with developing the eco-friend equipment due to its high quality of products. In the domestic industry, it has been pointed out that the mechanical polishing technique for molds and dies is relatively expensive and does not produce the required surface roughness. Therefore, in this R and D, techniques obtained from the ion source and the ion beam irradiation techniques developed for the proton accelerator has been applied to polish the surface of molds and dies to solve the above-mentioned problems that take place during mechanical polishing. In case that ion beam polishing technique is used, we expect not only producing the high quality polished surfaces but also producing the economically valuable end-products. In this R and D project, we are aiming at establishing ion beam techniques for industrialization as well as mass production of low cost products with developing the economical instrumentation techniques. Also, as a result of this R and D it is expected that importing of precise molds and dies may be reduced and technical competitiveness will be enhanced

  10. Development of a polarized neutron beam line at Algerian research reactors using McStas software

    Energy Technology Data Exchange (ETDEWEB)

    Makhloufi, M., E-mail: makhloufi_8m@yahoo.fr [Centre de Recherche Nucléaire de Birine (Algeria); Salah, H. [Centre de Recherche Nucléaire d' Alger (Algeria)

    2017-02-01

    Unpolarized instrumentation has long been studied and designed using McStas simulation tool. But, only recently new models were developed for McStas to simulate polarized neutron scattering instruments. In the present contribution, we used McStas software to design a polarized neutron beam line, taking advantage of the available spectrometers reflectometer and diffractometer in Algeria. Both thermal and cold neutron was considered. The polarization was made by two types of supermirrors polarizers FeSi and CoCu provided by the HZB institute. For sake of performance and comparison, the polarizers were characterized and their characteristics reproduced. The simulated instruments are reported. Flipper and electromagnets for guide field are developed. Further developments including analyzers and upgrading of the existing spectrometers are underway. - Highlights: • Permit to evaluate the feasibility of a polarized neutron scattering instrument prior to its implementation. • Help to understand the origin of instrumental imperfections and offer an optimized set up configuration. • Provide the possibility to use the FeSi and CoCu supermirrors, designed to polarize spin up cold neutron, to polarize thermal neutron.

  11. Development of a polarized neutron beam line at Algerian research reactors using McStas software

    International Nuclear Information System (INIS)

    Makhloufi, M.; Salah, H.

    2017-01-01

    Unpolarized instrumentation has long been studied and designed using McStas simulation tool. But, only recently new models were developed for McStas to simulate polarized neutron scattering instruments. In the present contribution, we used McStas software to design a polarized neutron beam line, taking advantage of the available spectrometers reflectometer and diffractometer in Algeria. Both thermal and cold neutron was considered. The polarization was made by two types of supermirrors polarizers FeSi and CoCu provided by the HZB institute. For sake of performance and comparison, the polarizers were characterized and their characteristics reproduced. The simulated instruments are reported. Flipper and electromagnets for guide field are developed. Further developments including analyzers and upgrading of the existing spectrometers are underway. - Highlights: • Permit to evaluate the feasibility of a polarized neutron scattering instrument prior to its implementation. • Help to understand the origin of instrumental imperfections and offer an optimized set up configuration. • Provide the possibility to use the FeSi and CoCu supermirrors, designed to polarize spin up cold neutron, to polarize thermal neutron.

  12. Development of ASTM Standard for SiC-SiC Joint Testing Final Scientific/Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Jacobsen, George [General Atomics, San Diego, CA (United States); Back, Christina [General Atomics, San Diego, CA (United States)

    2015-10-30

    As the nuclear industry moves to advanced ceramic based materials for cladding and core structural materials for a variety of advanced reactors, new standards and test methods are required for material development and licensing purposes. For example, General Atomics (GA) is actively developing silicon carbide (SiC) based composite cladding (SiC-SiC) for its Energy Multiplier Module (EM2), a high efficiency gas cooled fast reactor. Through DOE funding via the advanced reactor concept program, GA developed a new test method for the nominal joint strength of an endplug sealed to advanced ceramic tubes, Fig. 1-1, at ambient and elevated temperatures called the endplug pushout (EPPO) test. This test utilizes widely available universal mechanical testers coupled with clam shell heaters, and specimen size is relatively small, making it a viable post irradiation test method. The culmination of this effort was a draft of an ASTM test standard that will be submitted for approval to the ASTM C28 ceramic committee. Once the standard has been vetted by the ceramics test community, an industry wide standard methodology to test joined tubular ceramic components will be available for the entire nuclear materials community.

  13. Growth temperature and dopant species effects on deep levels in Si grown by low temperature molecular beam epitaxy

    International Nuclear Information System (INIS)

    Chung, Sung-Yong; Jin, Niu; Rice, Anthony T.; Berger, Paul R.; Yu, Ronghua; Fang, Z-Q.; Thompson, Phillip E.

    2003-01-01

    Deep-level transient spectroscopy measurements were performed in order to investigate the effects of substrate growth temperature and dopant species on deep levels in Si layers during low-temperature molecular beam epitaxial growth. The structures studied were n + -p junctions using B doping for the p layer and p + -n junctions using P doping for the n layer. While the density of hole traps H1 (0.38-0.41 eV) in the B-doped p layers showed a clear increase with decreasing growth temperature from 600 to 370 degree sign C, the electron trap density was relatively constant. Interestingly, the minority carrier electron traps E1 (0.42-0.45 eV) and E2 (0.257 eV), found in the B-doped p layers, are similar to the majority carrier electron traps E11 (0.48 eV) and E22 (0.269 eV) observed in P-doped n layers grown at 600 degree sign C. It is hypothesized that these dominating electron traps are associated with pure divacancy defects and are independent of the dopant species

  14. Synthesis of Pt nanoparticles and their burrowing into Si due to synergistic effects of ion beam energy losses

    Directory of Open Access Journals (Sweden)

    Pravin Kumar

    2014-10-01

    Full Text Available We report the synthesis of Pt nanoparticles and their burrowing into silicon upon irradiation of a Pt–Si thin film with medium-energy neon ions at constant fluence (1.0 × 1017 ions/cm2. Several values of medium-energy neon ions were chosen in order to vary the ratio of the electronic energy loss to the nuclear energy loss (Se/Sn from 1 to 10. The irradiated films were characterized using Rutherford backscattering spectroscopy (RBS, atomic force microscopy (AFM, scanning electron microscopy (SEM, X-ray diffraction (XRD and high resolution transmission electron microscopy (HRTEM. A TEM image of a cross section of the film irradiated with Se/Sn = 1 shows ≈5 nm Pt NPs were buried up to ≈240 nm into the silicon. No silicide phase was detected in the XRD pattern of the film irradiated at the highest value of Se/Sn. The synergistic effect of the energy losses of the ion beam (molten zones are produced by Se, and sputtering and local defects are produced by Sn leading to the synthesis and burrowing of Pt NPs is evidenced. The Pt NP synthesis mechanism and their burrowing into the silicon is discussed in detail.

  15. Development of an energy analyzer as diagnostic of beam-generated plasma in negative ion beam systems

    Science.gov (United States)

    Sartori, E.; Carozzi, G.; Veltri, P.; Spolaore, M.; Cavazzana, R.; Antoni, V.; Serianni, G.

    2017-08-01

    The measurement of the plasma potential and the energy spectrum of secondary particles in the drift region of a negative ion beam offers an insight into beam-induced plasma formation and beam transport in low pressure gasses. Plasma formation in negative-ion beam systems, and the characteristics of such a plasma are of interest especially for space charge compensation, plasma formation in neutralizers, and the development of improved schemes of beam-induced plasma neutralisers for future fusion devices. All these aspects have direct implications in the ITER Heating Neutral Beam and the operation of the prototypes, SPIDER and MITICA, and also have important role in the conceptual studies for NBI systems of DEMO, while at present experimental data are lacking. In this paper we present the design and development of an ion energy analyzer to measure the beam plasma formation and space charge compensation in negative ion beams. The diagnostic is a retarding field energy analyzer (RFEA), and will measure the transverse energy spectra of plasma molecular ions. The calculations that supported the design are reported, and a method to interpret the measurements in negative ion beam systems is also proposed. Finally, the experimental results of the first test in a magnetron plasma are presented.

  16. Development of an irradiation device for electron beam wastewater treatment

    International Nuclear Information System (INIS)

    Rela, Paulo Roberto

    2003-01-01

    When domestic or industrial effluents with synthetic compounds are disposed without an adequate treatment, they impact negatively the environment with damages to aquatic life and for the human being. Both population and use of goods and services that contribute for the hazardous waste are growing. Hazardous regulations are becoming more restrictive and technologies, which do not destroy these products, are becoming less acceptable. The electron beam radiation process is an advanced oxidation process, that produces highly reactive radicals resulting in mineralization of the contaminant. In this work was developed an irradiation system in order to optimize the interaction of electron beam delivered from the accelerator with the processed effluent. It is composed by an irradiation device where the effluent presents to the electron beam in an up flow stream and a process control unit that uses the calorimetric principle. The developed irradiation device has a different configuration from the devices used by others researchers that are working with this technology. It was studied the technical and economic feasibility, comparing with the literature the results of the irradiation device demonstrated that it has a superior performance, becoming an process for use in disinfection and degradation of hazardous organic compounds of wastewater from domestic and industrial origin, contributing as an alternative technology for Sanitary Engineering. (author)

  17. Development of L-band, 10MW multi beam klystron

    International Nuclear Information System (INIS)

    Irikura, M.; Miyake, S.; Yano, A.; Kazakov, S.; Larionov, A.; Teryaev, V.; Chin, Y.H.

    2004-01-01

    A 10-MW, L-band multi beam klystron (MBK) for TESLA linear collider and TESLA XFEL has been under development at Toshiba Electron Tubes and Devices Co., Ltd. (TETD) in collaboration with KEK. The TESLA requires pulsed klystrons capable of 10 MW output power at 1300 MHz with 1.5 ms pulse length and a repetition rate of 10 pps. The MBK with 6 low-perveance beams in parallel enables us to operate at lower cathode voltage with higher efficiency. The design work has been accomplished and the fabrication is under way. We are going to start conditioning and testing of prototype no.0 in the middle of July 2004. The design overview will be presented. (author)

  18. Electron-beam-induced reactivation of Si dopants in hydrogenated two-dimensional AlGaAs heterostructures: a possible new route for III-V nanostructure fabrication

    International Nuclear Information System (INIS)

    Kurowski, Ludovic; Bernard, Dorothee; Constant, Eugene; Decoster, Didier

    2004-01-01

    Hydrogen incorporation in n-type Si-doped GaAs epilayers is a well-known process which leads to the neutralization of the active Si impurities with the formation of SiH complexes. Recently, we have shown that SiH complex dissociation and, consequently, Si-dopant reactivation could occur when the epilayers are exposed to an electron beam. Two epilayers have been studied: the first is a 0.35 μm thick hydrogenated Si-doped GaAs epilayer and the second is Si planar-doped AlGaAs/GaAs/InGaAs heterostructures. Firstly, Hall effect measurements have been carried out on the epilayers exposed, after RF hydrogen plasma exposition, to increasing electron doses with different injection energies. For the 2D heterostructures, we have observed that the free carrier density N s does not vary significantly for weak electron densities. This reactivation presents a threshold value, contrary to the 0.35 μm epilayer in which N s varies quite linearly. It will be shown that such phenomena might be attributed to the filling of surface states as the dopants are progressively reactivated. Then, using a high spatial resolution electron beam lithography system, nanometric conductive patterns have been fabricated starting from hydrogenated epilayers. Electric measurements have been performed and the results obtained show that about 15 nm spatial resolution could be expected. In conclusion, taking into account this spatial resolution, the high spatial contrast of conductivity which could be expected due to the existence of an electron dose threshold, and the high mobility of the AlGaAs/GaAs/InGaAs heterostructure, the effects described in this paper could open a new way for the fabrication of III-V 1D or 2D mesoscopic structures for electronic or optoelectronic applications

  19. Rare isotope beam energy measurements and scintillator developments for ReA3

    Science.gov (United States)

    Lin, Ling-Ying

    The ReAccelerator for 3 MeV/u beams (ReA3) at the National Superconducting Cyclotron Laboratory (NSCL) in Michigan State University can stop rare isotope beams produced by in-flight fragmentation and reaccelerate them in a superconducting linac. The precise knowledge of the energy and the energy spread of the ion beams extracted from the ReA3 linac is essential for experimental requirement in many applications. Beam energy determination methods such as implantation on a Si detector and/or using calibrated linac settings are precise within a few tens of keV/u. In order to determine beam energies with good resolution of less than 0.5 % FWHM, a 45 degree bending magnet with a movable slit is used to determine the absolute beam energy based on the magnetic rigidity. Two methods have been developed for the energy calibration of the beam analyzing magnet: gamma-ray nuclear resonance reactions and a time-of-flight (TOF) technique. The resonance energies of gamma-ray resonant reactions provide well-known and precise calibration points. The gamma ray yields of the 27Al(p,gamma)28Si at Ep= 992 keV and 632 keV resonances and 58Ni(p,gamma)59Cu at Ep= 1843 keV resonance have been measured with the high efficiency CAESAR (CAESium iodide ARray) and SuN (Summing NaI(Tl)) detectors. By fitting the observed resonant gamma-ray yields, not only the beam energy can be precisely correlated with the magnetic field but also beam energy spread can be obtained. The measured beam energy spread is consistent with beam optics calculations. A time-of-flight system for determining the absolute energy of ion beams and calibrating the 45 degree magnetic analyzer has been developed in ReA3 by using two identical secondary electron monitors (grid-MCP detectors) with appropriate separation. The TOF technique is applicable to the variety of beam energies and ion particles. Velocities of ion beam are determined by simultaneously measuring the arrival time of beam bunches at the two detectors with

  20. Conceptual development of the Laser Beam Manifold (LBM)

    Science.gov (United States)

    Campbell, W.; Owen, R. B.

    1979-01-01

    The laser beam manifold, a device for transforming a single, narrow, collimated beam of light into several beams of desired intensity ratios is described. The device consists of a single optical substrate with a metallic coating on both optical surfaces. By changing the entry point, the number of outgoing beams can be varied.

  1. Thickness-dependent blue shift in the excitonic peak of conformally grown ZnO:Al on ion-beam fabricated self-organized Si ripples

    Energy Technology Data Exchange (ETDEWEB)

    Basu, T.; Kumar, M.; Som, T., E-mail: tsom@iopb.res.in [Institute of Physics, Sachivalaya Marg, Bhubaneswar 751 005 (India); Nandy, S. [CENIMAT, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, Caparica 2829 516 (Portugal); Satpati, B. [Surface Physics and Material Science Division, Saha Institute of Nuclear Physics, Kolkata 700 064 (India); Saini, C. P.; Kanjilal, A. [Department of Physics, School of Natural Sciences, Shiv Nadar University, Gautam Budh Nagar, Uttar Pradesh 201 314 (India)

    2015-09-14

    Al-doped ZnO (AZO) thin films of thicknesses 5,10, 15, 20, and 30 nm were deposited on 500 eV argon ion-beam fabricated nanoscale self-organized rippled-Si substrates at room temperature and are compared with similar films deposited on pristine-Si substrates (without ripples). It is observed that morphology of self-organized AZO films is driven by the underlying substrate morphology. For instance, for pristine-Si substrates, a granular morphology evolves for all AZO films. On the other hand, for rippled-Si substrates, morphologies having chain-like arrangement (anisotropic in nature) are observed up to a thickness of 20 nm, while a granular morphology evolves (isotropic in nature) for 30 nm-thick film. Photoluminescence studies reveal that excitonic peaks corresponding to 5–15 nm-thick AZO films, grown on rippled-Si templates, show a blue shift of 8 nm and 3 nm, respectively, whereas the peak shift is negligible for 20-nm thick film (with respect to their pristine counter parts). The observed blue shifts are substantiated by diffuse reflectance study and attributed to quantum confinement effect, associated with the size of the AZO grains and their spatial arrangements driven by the anisotropic morphology of underlying rippled-Si templates. The present findings will be useful for making tunable AZO-based light-emitting devices.

  2. Low temperature growth of Co{sub 2}MnSi films on diamond semiconductors by ion-beam assisted sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Nishiwaki, M.; Ueda, K., E-mail: k-ueda@numse.nagoya-u.ac.jp; Asano, H. [Department of Crystalline Materials Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

    2015-05-07

    High quality Schottky junctions using Co{sub 2}MnSi/diamond heterostructures were fabricated. Low temperature growth at ∼300–400 °C by using ion-beam assisted sputtering (IBAS) was necessary to obtain abrupt Co{sub 2}MnSi/diamond interfaces. Only the Co{sub 2}MnSi films formed at ∼300–400 °C showed both saturation magnetization comparable to the bulk values and large negative anisotropic magnetoresistance, which suggests half-metallic nature of the Co{sub 2}MnSi films, of ∼0.3% at 10 K. Schottky junctions formed using the Co{sub 2}MnSi films showed clear rectification properties with rectification ratio of more than 10{sup 7} with Schottky barrier heights of ∼0.8 eV and ideality factors (n) of ∼1.2. These results indicate that Co{sub 2}MnSi films formed at ∼300–400 °C by IBAS are a promising spin source for spin injection into diamond semiconductors.

  3. Chemical effect of Si+ ions on the implantation-induced defects in ZnO studied by a slow positron beam

    Science.gov (United States)

    Jiang, M.; Wang, D. D.; Chen, Z. Q.; Kimura, S.; Yamashita, Y.; Mori, A.; Uedono, A.

    2013-01-01

    Undoped ZnO single crystals were implanted with 300 keV Si+ ions to a dose of 6 × 1016 cm-2. A combination of X-ray diffraction (XRD), positron annihilation, Raman scattering, high resolution transmission electron microscopy (HRTEM), and photoluminescence (PL) was used to study the microstructure evolution after implantation and subsequent annealing. A very large increase of Doppler broadening S parameters in Si+-implanted region was detected by using a slow positron beam, indicating that vacancy clusters or microvoids are induced by implantation. The S parameters increase further after annealing up to 700 °C, suggesting agglomeration of these vacancies or microvoids to larger size. Most of these defects are removed after annealing up to 1100 °C. The other measurements such as XRD, Raman scattering, and PL all indicate severe damage and even disordered structure induced by Si+ implantation. The damage and disordered lattice shows recovery after annealing above 700 °C. Amorphous regions are observed by HRTEM measurement, directly testifies that amorphous phase is induced by Si+ implantation in ZnO. Analysis of the S - W correlation and the coincidence Doppler broadening spectra gives direct evidence of SiO2 precipitates in the sample annealed at 700 °C, which strongly supports the chemical effect of Si ions on the amorphization of ZnO lattice.

  4. Development of thin-film Si HYBRID solar module

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Akihiko; Gotoh, Masahiro; Sawada, Toru; Fukuda, Susumu; Yoshimi, Masashi; Yamamoto, Kenji; Nomura, Takuji [Kaneka Corporation, 2-1-1, Hieitsuji, Otsu, Shiga 520-0104 (Japan)

    2009-06-15

    The device current-voltage (I-V) characteristics of thin-film silicon stacked tandem solar modules (HYBRID modules), consisting of a hydrogenated amorphous silicon (a-Si:H) cell and a thin-film crystalline silicon solar cell ({mu}c-Si), have been investigated under various spectral irradiance distributions. The performance of the HYBRID module varied periodically in natural sunlight due to the current-limiting property of the HYBRID module and the environmental effects. The behavior based on the current-limiting property was demonstrated by the modelling of the I-V curves using the linear interpolation method for each component cell. The improvement of the performance for the HYBRID module in natural sunlight will also be discussed from the viewpoint of the device design of the component cells. (author)

  5. Development of the microstrip silicon detector for imaging of fast processes at a synchrotron radiation beam

    Energy Technology Data Exchange (ETDEWEB)

    Aulchenko, V. [Budker Institute of Nuclear Physics, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, 630090 Novosibirsk, Russian Federtion (Russian Federation); Pruuel, E. [Lavrentiev Institute of Hydrodynamics, 630090 Novosibirsk, Russian Federtion (Russian Federation); Novosibirsk State University, 630090 Novosibirsk, Russian Federtion (Russian Federation); Shekhtman, L. [Budker Institute of Nuclear Physics, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, 630090 Novosibirsk, Russian Federtion (Russian Federation); Ten, K. [Lavrentiev Institute of Hydrodynamics, 630090 Novosibirsk, Russian Federtion (Russian Federation); Tolochko, B. [Institute of Solid State chemistry and Mechanochemistry, 630090 Novosibirsk, Russian Federtion (Russian Federation); Novosibirsk State University, 630090 Novosibirsk, Russian Federtion (Russian Federation); Zhulanov, V. [Budker Institute of Nuclear Physics, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, 630090 Novosibirsk, Russian Federtion (Russian Federation)

    2017-02-11

    In situ imaging of explosions allows to study material properties under very high pressures and temperatures. Synchrotron radiation (SR) is a powerful tool for such studies because of its unique time structure. Flashes of X-rays from individual bunches in a storage ring are so short that an object under study does not move more than 1–10 μm during exposure. If a detector is able to store images synchronously with bunches of an SR source the time resolution of such method will be determined by the duration of SR flash from individual bunch. New beam line at the VEPP-4M storage ring will allow to get X-Ray flux from each bunch close to 10{sup 6} photons/channel where channel area is 0.05×0.5 mm{sup 2} and average beam energy is about 30 keV. Bunches in the machine can be grouped into trains with 20 ns time gap. In order to meet these requirements a new detector development was started based on Si microstrip technology. The detector with a new dedicated front-end chip will be able to record images with maximum signal equivalent to 10{sup 6} photons/channel, with signal to noise ratio of ∼10{sup 3}, spatial resolution of 50 μm and maximum frame rate of 50 MHz. The detector has to drive very high peak and average currents without affecting the front-end chip, therefore a specific design of Si sensor should be developed. The front-end chip has to provide signal measurements with the dynamic range of about 10{sup 4} or more and recording of the signal to an analogue memory with the rate of 50 MHz. The concept of such detector is discussed in the paper. The results of the simulations of the main detector parameters and the results of the first measurements with the prototype sensors are presented.

  6. Development of laser beam welding for the lip seal configuration

    International Nuclear Information System (INIS)

    Yadav, Ashish; Joshi, Jaydeep; Singh, Dhananjay Kumar; Natu, Harshad; Rotti, Chandramouli; Bandyopadhyay, Mainak; Chakraborty, Arun

    2015-01-01

    Highlights: • Laser welding parameter optimization for required weld penetration. • Parametric study of actual scenarios like air gap, plate & beam misalignment. • Destructive and non-destructive examination of the welds and He-leak testing. - Abstract: A vacuum seal using the lip sealing technique is emerging as the most likely choice for fusion devices, to comply with the requirement of maintainability. The welding technology considered for lip sealing is laser welding, due to the attributes of small spot diameter, low concentrated heat input, high precision and penetration. To establish the process, an experiment has been conducted on a sample size of 150 mm × 50 mm having thickness of 2 mm, material AISI304L to assess the dependence of beam parameters like, laser power, speed and focusing distance on penetration and quality of weld joint. Further, the assessment of the effect of welding set-up variables like air-gap between plates, plate misalignment, and laser beam misalignment on the weld quality is also required. This paper presents the results of this experimental study and also the plan for developing a large (∼10 m) size laser welded seal, that simulates, appropriately, the configuration required in large dimension fusion devices.

  7. Development of a diplexer based on dielectric beam splitters

    International Nuclear Information System (INIS)

    D'Arcangelo, O.; Alessi, E.; Bin, W.; Bruschi, A.; Moro, A.; Muzzini, V.

    2011-01-01

    Controllable power combination and distribution of multiple sources into multiple transmission lines may increase efficiency and flexibility of ECRH systems. A new quasi-optical version of diplexer based on a resonating system, coupling two transmission lines, is under development at IFP-CNR. Two dielectric beam splitters work as input/output ports for the diplexer, which can be thought as a Fabry-Perot resonator. A third beam splitter can be inserted in the middle of the resonator. In this case the diplexer looks like a pair of mirrored resonators coupled by through the central splitter. Each beam splitter is made of a water-free silica layer, three quarter of wavelength thick at 140 GHz. The simulated performances were tested as a function of the frequency on the two splitters simpler model. Preliminary results confirm qualitatively theoretical predictions as well as the good channel separation obtainable with the three splitters version. Present work describes the system realization together with the low power tests performed.

  8. Development of a radioactive ion beam test stand at LBNL

    International Nuclear Information System (INIS)

    Burke, J.; Freedman, S.J.; Fujikawa, B.; Gough, R.A.; Lyneis, C.M.; Vetter, P.; Wutte, D.; Xie, Z.Q.

    1998-01-01

    For the on-line production of a 14 O + ion beam, an integrated target--transfer line ion source system is now under development at LBNL. 14 O is produced in the form of CO in a high temperature carbon target using a 20 MeV 3 He beam from the LBNL 88'' Cyclotron via the reaction 12 C( 3 He,n) 14 O. The neutral radioactive CO molecules diffuse through an 8 m room temperature stainless steel line from the target chamber into a cusp ion source. The molecules are dissociated, ionized and extracted at energies of 20 to 30 keV and mass separated with a double focusing bending magnet. The different components of the setup are described. The release and transport efficiency for the CO molecules from the target through the transfer line was measured for various target temperatures. The ion beam transport efficiencies and the off-line ion source efficiencies for Ar, O 2 and CO are presented. Ionization efficiencies of 28% for Ar + , 1% for CO, 0.7% for O + , 0.33 for C + have been measured

  9. Achievement and development of neutron beam utilization in research reactors

    International Nuclear Information System (INIS)

    Isshiki, Masahiko

    1996-01-01

    Especially regarding the neutron beam experiment in Japan, the basic research has been developed by utilizing the JRR-2 of Japan Atomic Energy Research Institute and the KUR of Kyoto University over long years. Now, the JRR-3M of JAERI was revived as a high performance, general purpose reactor, and bears important roles as the neutron beam experiment center in Japan. Thanks to one of the most powerful reactor neutron sources in the world and the cold neutron source, the environment of research was greatly improved, and the excellent results of researches began to be reported. The discovery of neutrons by Chadwick and the history of the related researches are described. As neutron sources, radioisotopes, accelerators and nuclear reactors are properly used corresponding to purposes. As the utilization of research reactors for neutron sources, the utilization for irradiation and neutron beam experiment are carried out. The outline of the research reactor JRR-3M is explained. The state of utilization in neutron scattering experiment, neutron radiography, prompt γ-ray analysis and the medical irradiation of neutrons is reported. (K.I.)

  10. Development of the RRR cold neutron beam facility

    International Nuclear Information System (INIS)

    Lovotti, Osvaldo; Masriera, Nestor; Lecot, Carlos; Hergenreder, Daniel

    2002-01-01

    This paper describes some general design issues on the neutron beam facilities (cold neutron source and neutron beam transport system) of the Replacement Research Reactor (RRR) for the Australian Nuclear Science and Technology Organisation (ANSTO). The description covers different aspect of the design: the requirements that lead to an innovative design, the overall design itself, the definition of a technical approach in order to develop the necessary design solutions, and finally the organizational framework by which international expertise from five different institutions is integrated. From the technical viewpoint, the RRR-CNS is a liquid Deuterium (LD2) moderator, sub-cooled to ensure maximum moderation efficiency, flowing within a closed natural circulation thermosyphon loop. The thermosyphon is surrounded by a zirconium alloy CNS vacuum containment that provides thermal insulation and a multiple barriers scheme to prevent Deuterium from mixing with water or air. Consistent with international practice, this vessel is designed to withstand any hypothetical energy reaction should Deuterium and air mix in its interior. The 'cold' neutrons are then taken by the NBTS and transported by the neutron guide system into the reactor beam hall and neutron guide hall, where neutron scattering instruments are located. From the management viewpoint, the adopted distributed scheme is successful to manage the complex interfacing between highly specialized technologies, allowing a smooth integration within the project. (author)

  11. Development of laser beam welding for the lip seal configuration

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Ashish, E-mail: ashish.yadav@iter-india.org [ITER-India, Institute for Plasma Research, Sector 25, Gandhinagar 382016, Gujarat (India); Joshi, Jaydeep; Singh, Dhananjay Kumar [ITER-India, Institute for Plasma Research, Sector 25, Gandhinagar 382016, Gujarat (India); Natu, Harshad [Magod Laser Machining Pvt. Ltd., KIADB Ind. Area, Jigani, Anekal Taluk, Bengaluru 560105 (India); Rotti, Chandramouli; Bandyopadhyay, Mainak; Chakraborty, Arun [ITER-India, Institute for Plasma Research, Sector 25, Gandhinagar 382016, Gujarat (India)

    2015-10-15

    Highlights: • Laser welding parameter optimization for required weld penetration. • Parametric study of actual scenarios like air gap, plate & beam misalignment. • Destructive and non-destructive examination of the welds and He-leak testing. - Abstract: A vacuum seal using the lip sealing technique is emerging as the most likely choice for fusion devices, to comply with the requirement of maintainability. The welding technology considered for lip sealing is laser welding, due to the attributes of small spot diameter, low concentrated heat input, high precision and penetration. To establish the process, an experiment has been conducted on a sample size of 150 mm × 50 mm having thickness of 2 mm, material AISI304L to assess the dependence of beam parameters like, laser power, speed and focusing distance on penetration and quality of weld joint. Further, the assessment of the effect of welding set-up variables like air-gap between plates, plate misalignment, and laser beam misalignment on the weld quality is also required. This paper presents the results of this experimental study and also the plan for developing a large (∼10 m) size laser welded seal, that simulates, appropriately, the configuration required in large dimension fusion devices.

  12. Latest R&D news and beam test performance of the highly granular SiW-ECAL technological prototype for the ILC

    Science.gov (United States)

    Irles, A.

    2018-02-01

    High precision physics at future colliders as the International Linear Collider (ILC) require unprecedented high precision in the determination of the energy of final state particles. The needed precision will be achieved thanks to the Particle Flow algorithms (PF) which require highly granular and hermetic calorimeters systems. The physical proof of concept of the PF was performed in the previous campaign of beam tests of physic prototypes within the CALICE collaboration. One of these prototypes was the physics prototype of the Silicon-Tungsten Electromagnetic Calorimeter (SiW-ECAL) for the ILC. In this document we present the latest news on R&D of the next generation prototype, the technological prototype with fully embedded very front-end (VFE) electronics, of the SiW-ECAL. Special emphasis is given to the presentation and discussion of the first results from the beam test done at DESY in June 2017. The physics program for such beam test consisted in the calibration and commissioning of the current set of available SiW ECAL modules; the test of performance of individual slabs under 1T magnetic fields; and the study of electromagnetic showers events.

  13. Study of the structural and optical properties of GaP(N) layers synthesized by molecular-beam epitaxy on Si(100) 4° substrates

    Energy Technology Data Exchange (ETDEWEB)

    Kryzhanovskaya, N. V., E-mail: NataliaKryzh@gmail.com; Polubavkina, Yu. S. [Russian Academy of Sciences, St. Petersburg National Research Academic University–Nanotechnology Research and Education Center (Russian Federation); Nevedomskiy, V. N. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation); Nikitina, E. V.; Lazarenko, A. A. [Russian Academy of Sciences, St. Petersburg National Research Academic University–Nanotechnology Research and Education Center (Russian Federation); Egorov, A. Yu. [St. Petersburg National Research University of Information Technologies, Mechanics, and Optics (Russian Federation); Maximov, M. V.; Moiseev, E. I.; Zhukov, A. E. [Russian Academy of Sciences, St. Petersburg National Research Academic University–Nanotechnology Research and Education Center (Russian Federation)

    2017-02-15

    The structural and optical properties of GaP and GaPN layers synthesized by molecular-beam epitaxy on Si(100) substrates misoriented by 4° are studied. The possibility of producing GaP buffer layers that exhibit a high degree of heterointerface planarity and an outcropping dislocation density of no higher than ~2 × 10{sup 8} cm{sup –2} is shown. Emission from the Si/GaP/GaPN structure in the spectral range of 630–640 nm at room temperature is observed. Annealing during growth of the Si/GaP/GaPN structure makes it possible to enhance the room-temperature photoluminescence intensity by a factor of 2.6, with no shift of the maximum of the emission line.

  14. Effects of B4C Addition on the Laser Beam Welding Characteristics of Al/SiC MMCs Produced By P/M

    Directory of Open Access Journals (Sweden)

    Serdar KARAOĞLU

    2011-01-01

    Full Text Available Fusion weldability characteristics of metal matrix composites (MMC produced by powder metallurgy (P/M are usually insufficient due to unwanted micro-structural changes that occur during welding. This study aims to investigate the effects of B4C addition as reinforcement on the weld quality of Al/SiC MMCs. After the production of Al/SiC MMCs by P/M with or without the addition of B4C, laser beam welding (LBW characteristics of the materials were investigated by focusing on the integrity of the welds. Optical microscopy (OM, scanning electron microscopy (SEM, and energy dispersive X-ray analysis (EDX were utilized for the characterization of the welds. Results show that Al/SiC MMCs produced by P/M can not be easily welded by LBW, but weldability characteristics of the material can be improved by the addition of B4C.

  15. Study of the structural and optical properties of GaP(N) layers synthesized by molecular-beam epitaxy on Si(100) 4° substrates

    International Nuclear Information System (INIS)

    Kryzhanovskaya, N. V.; Polubavkina, Yu. S.; Nevedomskiy, V. N.; Nikitina, E. V.; Lazarenko, A. A.; Egorov, A. Yu.; Maximov, M. V.; Moiseev, E. I.; Zhukov, A. E.

    2017-01-01

    The structural and optical properties of GaP and GaPN layers synthesized by molecular-beam epitaxy on Si(100) substrates misoriented by 4° are studied. The possibility of producing GaP buffer layers that exhibit a high degree of heterointerface planarity and an outcropping dislocation density of no higher than ~2 × 10"8 cm"–"2 is shown. Emission from the Si/GaP/GaPN structure in the spectral range of 630–640 nm at room temperature is observed. Annealing during growth of the Si/GaP/GaPN structure makes it possible to enhance the room-temperature photoluminescence intensity by a factor of 2.6, with no shift of the maximum of the emission line.

  16. Relaxation of a strained 3C-SiC(1 1 1) thin film on silicon by He+ and O+ ion beam defect engineering

    International Nuclear Information System (INIS)

    Häberlen, M.; Murphy, B.; Stritzker, B.; Lindner, J.K.N.

    2012-01-01

    In this paper we report on the successful reduction of tensile strain in a thin strained ion-beam synthesized 3C-SiC(1 1 1) layer on silicon. The creation of a near-interface defect structure consisting of nanometric voids and stacking fault type defects by He ion implantation and subsequent annealing yields significant relaxation in the top SiC film. The microstructure of the defect layer is studied by transmission electron microscopy, and the strain state of the 3C-SiC layer was studied by high-resolution X-ray diffraction in a parallel beam configuration. Typical process conditions for the growth of GaN films on the SiC layer were emulated by high temperature treatments in a rapid thermal annealer or a quartz tube furnace. It is found that prolonged annealing at high temperatures leads to ripening of the voids and to a weaker reduction of the tensile strain. It is shown that this problem can be overcome by the co-implantation of oxygen ions to form highly thermally stable void/extended defect structures.

  17. Development Status and Performance Comparisons of Environmental Barrier Coating Systems for SiCSiC Ceramic Matrix Composites

    Science.gov (United States)

    Zhu, Dongming; Harder, Bryan

    2016-01-01

    Environmental barrier coatings (EBC) and SiCSiC ceramic matrix composites (CMCs) will play a crucial role in future aircraft turbine engine systems, because of their ability to significantly increase engine operating temperatures, reduce engine weight and cooling requirements. This paper presents current NASA EBC-CMC development emphases including: the coating composition and processing improvements, laser high heat flux-thermal gradient thermo-mechanical fatigue - environmental testing methodology development, and property evaluations for next generation EBC-CMC systems. EBCs processed with various deposition techniques including Plasma Spray, Electron Beam - Physical Vapor Deposition, and Plasma Spray Physical Vapor Deposition (PS-PVD) will be particularly discussed. The testing results and demonstrations of advanced EBCs-CMCs in complex simulated engine thermal gradient cyclic fatigue, oxidizing-steam and CMAS environments will help provide insights into the coating development strategies to meet long-term engine component durability goals.

  18. Development of applications for Indian industry using electron beam technology

    International Nuclear Information System (INIS)

    Sarma, K.S.S.; Khader, S.A.; Sabharwal, S.

    2009-01-01

    This paper presents a report on the industrial applications that have been developed and demonstrated to the Indian industry using 2MeV/20kW Electron Beam accelerator at BARC-BRIT in the field of polymer modifications (crosslinking and degradation), gem stone coloration etc. Technological scale demonstration of the applications citing the benefits in terms of clean technology and better economics, encouraged three companies in private industry to set up EB facilities for the treatment of cable insulations, heat shrinkable products, diamond and gem stones during the last five years. Recent work on EB processing of automobile rubber tires is also included. (author)

  19. Development of neutral beams for fusion plasma heating

    International Nuclear Information System (INIS)

    Haselton, H.H.; Pyle, R.V.

    1980-01-01

    A state-of-the-art account of neutral beam technology at the LBL/LLNL and ORNL facilities is given with emphasis on positive-ion-based systems. The advances made in the last few years are elaborated and problem areas are identified. The ORNL program has successfully completed the neutral injection systems for PLT, ISX-B, and most recently, PDX and the ISX-B upgrade. All of these are high current (60 to 100 A), medium energy (40 to 50 keV) systems. This program is also engaged in the development of a reactor-grade advanced positive ion system (150 to 200 kV/100 A/5 to 10 s) and a multimegawatt, long pulse (30 s) heating system for ISX-C. In a joint program, LBL and LLNL are developing and testing neutral beam injection systems based on the acceleration of positive ions for application in the 80- to 160-keV range on MFTF-B, D-III, TFTR/TFM, ETF, MNS, etc. A conceptual design of a 160-keV injection system for the German ZEPHYR project is in progress at LBL/LLNL and independently at ORNL. The laboratories are also engaged in the development of negative-ion-based systems for future applications at higher energies

  20. Development of neutral beams for fusion plasma heating

    Energy Technology Data Exchange (ETDEWEB)

    Haselton, H.H.; Pyle, R.V.

    1980-01-01

    A state-of-the-art account of neutral beam technology at the LBL/LLNL and ORNL facilities is given with emphasis on positive-ion-based systems. The advances made in the last few years are elaborated and problem areas are identified. The ORNL program has successfully completed the neutral injection systems for PLT, ISX-B, and most recently, PDX and the ISX-B upgrade. All of these are high current (60 to 100 A), medium energy (40 to 50 keV) systems. This program is also engaged in the development of a reactor-grade advanced positive ion system (150 to 200 kV/100 A/5 to 10 s) and a multimegawatt, long pulse (30 s) heating system for ISX-C. In a joint program, LBL and LLNL are developing and testing neutral beam injection systems based on the acceleration of positive ions for application in the 80- to 160-keV range on MFTF-B, D-III, TFTR/TFM, ETF, MNS, etc. A conceptual design of a 160-keV injection system for the German ZEPHYR project is in progress at LBL/LLNL and independently at ORNL. The laboratories are also engaged in the development of negative-ion-based systems for future applications at higher energies.

  1. Recovery effects due to the interaction between nuclear and electronic energy losses in SiC irradiated with a dual-ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Thomé, Lionel, E-mail: thome@csnsm.in2p3.fr; Debelle, Aurélien; Garrido, Frédérico; Sattonnay, Gaël; Mylonas, Stamatis [Centre de Sciences Nucléaires et de Sciences de la Matière, CNRS-IN2P3-Université Paris-Sud, Bât. 108, F-91405 Orsay (France); Velisa, Gihan [CEA, DEN, Service de Recherches de Métallurgie Physique, Laboratoire JANNUS, F-91191 Gif-sur-Yvette (France); Horia Hulubei National Institute for Physics and Nuclear Engineering, P.O.B. MG-6, 077125 Magurele (Romania); Miro, Sandrine; Trocellier, Patrick; Serruys, Yves [CEA, DEN, Service de Recherches de Métallurgie Physique, Laboratoire JANNUS, F-91191 Gif-sur-Yvette (France)

    2015-03-14

    Single and dual-beam ion irradiations of silicon carbide (SiC) were performed to study possible Synergetic effects between Nuclear (S{sub n}) and Electronic (S{sub e}) Energy Losses. Results obtained combining Rutherford backscattering in channeling conditions, Raman spectroscopy, and transmission electron microscopy techniques show that dual-beam irradiation of SiC induces a dramatic change in the final sample microstructure with a substantial decrease of radiation damage as compared to single-beam irradiation. Actually, a defective layer containing dislocations is formed upon dual-beam irradiation (S{sub n} and S{sub e}), whereas single low-energy irradiation (S{sub n} alone) or even sequential (S{sub n} + S{sub e}) irradiations lead to full amorphization. The healing process is ascribed to the electronic excitation arising from the electronic energy loss of swift ions. These results shed new light on the long-standing puzzling problem of the existence of a possible synergy between S{sub n} and S{sub e} in ion-irradiation experiments. This work is interesting for both fundamental understanding of the ion-solid interactions and technological applications in the nuclear industry where recovery S{sub n}/S{sub e} effects may preserve the integrity of nuclear devices.

  2. Electron-beam-induced structure transformation of the quasicrystalline phases of the Al 62Cu 20Co 15Si 3 alloy

    Science.gov (United States)

    Reyes-Gasga, J.; R. Garcia, G.; Jose-Yacaman, M.

    1995-02-01

    Some details on the phase transformation experienced by the quasicrystalline phases of the Al 62Cu 20Co 15Si 3 alloy under a 400 kV electron beam are given. The transition is observed in situ with a high resolution electron microscope and recorded on video tape. The results show that the electron beam radiation produces a sequence of changes similar to the ones observed in an ion-beam-induced amorphization process. Considering electron radiation damage analysis, the results agree well with the "flip-flop" model [Coddens, Bellisent, Calvayrac and Ambroise (1991) Europhys. Lett.16, 271] where the transition from a quasicrystalline phase to a crystalline phase is produced by atomic displacements but not in a cascade way.

  3. Development and characterization of HIP joining techniques for Si3N4 materials

    International Nuclear Information System (INIS)

    Sun Woo, J.

    1991-09-01

    The report deals with the development and optimization of reproducible techniques for joining Si 3 N 4 with Si 3 N 4 without interlayers consisting of other materials, applying hot isostatic pressing and vacuum plasma spraying. Furthermore, experiments are reported that have been performed in addition to the above-mentioned, for preparing Si 3 N 4 sintered specimens without sintering additives, applying the HIP technique. The resulting specimens have been tested for their joining characteristics, which are reported. All reported experiments have been performed varying essential parameters such as HIP temperature, pressure, holding time, surface roughness, and heat treatment. Every parameter has been examined individually for its effect on the bonding strength of the prepared Si 3 N 4 -Si 3 N 4 joint, applying 4P bending tests at room temperature and at 1200deg C. (orig./MM) [de

  4. Development of mobile electron beam plant for environmental applications

    International Nuclear Information System (INIS)

    Han, Bumsoo; Kim, Jinkyu; Kang, Wongu; Choi, Jang Seung; Jeong, Kwang-Young

    2016-01-01

    Due to the necessity of pilot scale test facility for continuous treatment of wastewater and gases on site, a mobile electron beam irradiation system mounted on a trailer has developed. This mobile electron beam irradiation system is designed for the individual field application with self-shielded structure of steel plate and lead block which will satisfy the required safety figures of International Commission on Radiological Protection (ICRP). Shielding of a mobile electron accelerator of 0.7 MeV, 30 mA has been designed and examined by Monte Carlo technique. Based on a 3-D model of electron accelerator shielding which is designed with steel and lead shield, radiation leakage was examined using the Monte Carlo N-Particle Transport (MCNP) Code. Simulations with two different versions (version 4c2 and version 5) of MCNP code showed agreements within statistical uncertainties, and the highest leakage expected is 5.5061×10 −01 (1±0.0454) μSv/h, which is far below the tolerable radiation dose limit for occupational workers. This unit could treat up to 500 m 3 of liquid waste per day at 2 kGy or 10,000 N m 3 of gases per hour at 15 kGy. - Highlights: • A mobile electron beam irradiation system mounted on a trailer has developed. • It is designed for treatment of wastewater and flue gas on site. • Shielding of 0.7 MeV, 30 mA accelerator has done by a Monte Carlo technique. • It can treat up to 500 m 3 /d of liquid waste at 2 kGy or 10,000 N m 3 /h of gas at 15 kGy.

  5. Process heat exchanger for SO3 decomposer fabricated with Ni-based alloys surface modified by SiC film deposition and N ion beam bombardment

    International Nuclear Information System (INIS)

    Park, Jae-Won; Kim, Hyung-Jin; Choi, Yong-Woon; Kim, Yong-Wan

    2007-01-01

    In the iodine-sulfur (IS) cycle for the hydrogen production using the high temperature gas-cooled reactor (HTGR), one of the important components is the SO 3 decomposer which generates SO 2 and SO 3 gases under high temperature conditions. Since this environment is extremely corrosive, the materials used for the decomposer should meet excellent mechanical properties at the elevated temperature as well as high corrosion resistance in SO 2 /SO 3 atmospheres. In general, ceramics are protective against the corrosion, but metals exhibit limited corrosion resistance. In this work, the ceramic coating on the metallic substrate was studied. We selected SiC as coating materials and Ni-based alloys as the substrate materials. Since the adhesion between the coated layer and the substrate is most crucial in this application, we attempted to develop Ion Beam Mixing (IBM) technique to produce a highly adherent coated layer. For the fabrication of process heat exchange for SO 3 decomposer, the diffusion bonding at ∼900 .deg. C is employed because this temperature does not affect the mechanical properties of materials

  6. Development of capacitive beam position, beam current and Schottky-signal monitors for the Cryogenic Storage Ring (CSR)

    International Nuclear Information System (INIS)

    Laux, Felix

    2011-01-01

    In this thesis novel techniques based on capacitive pickups for the determination of the beam current, the beam position and the Schottky-signal in storage rings have been developed. Beam current measurements at the heavy ion storage ring TSR with a capacitive pickup have been found in very good agreement with the theory. Using this device the accurate measurement of beam currents at the TSR far below 1 μA is now possible. This method will also be used at the Cryogenic Storage Ring (CSR) at which beam currents in the range of 1 nA-1 μA are expected. For the first time, position measurements with a resonant amplifier system for capacitive pickups have been examined at the TSR for later use of this technique in the CSR. With this method an increased signal-to-noise ratio can be achieved using a parallel inductance. A comparison with measurements using the rest gas beam profile monitor has shown very good agreement even at very low intensities. Experiments with the cryo-capable electronics for the CSR beam position monitors have shown an achievable quality factor of Q=500, resulting in the prospect of precise position measurements at the CSR even at very low beam currents. The CSR Schottky-Pickup will also be equipped with a resonant amplifier system with a comparable quality factor. An estimation of the signal-to-noise ratio suggests a detection limit of a few protons. (orig.)

  7. Preliminary study in development of glass-ceramic based on SiO2-LiO2 system, starting of different SiO2 starting powders

    International Nuclear Information System (INIS)

    Daguano, J.K.M.F.; Santos, F.A.; Santos, C.; Marton, L.F.M.; Conte, R.A.; Rodrigues Junior, D.; Melo, F.C.L.

    2009-01-01

    In this work, lithium disilicate glass-ceramics were developed starting of the rice ash- SiO 2 and Li 2 CO 3 powders. The results were compared with glass ceramics based on the lithium disilicate obtained by commercial SiO 2 powders. Glass were melted at 1580 deg C, and annealed at 850 deg C. X-Ray diffraction and scanning electron microscopy were used for characterization of the materials, and hardness and fracture toughness were evaluated using Vickers indentation method. Glasses with amorphous structure were obtained in both materials. After annealing, 'rice-ash' samples presented Li 2 SiO 3 and residual SiO 2 as crystalline phases. On the other side, commercial SiO 2 - Samples presented only Li 2 Si 2 O 5 as crystalline phases and the better results of hardness and fracture toughness. (author)

  8. Development of ion beam sputtering techniques for actinide target preparation

    Science.gov (United States)

    Aaron, W. S.; Zevenbergen, L. A.; Adair, H. L.

    1985-06-01

    Ion beam sputtering is a routine method for the preparation of thin films used as targets because it allows the use of a minimum quantity of starting material, and losses are much lower than most other vacuum deposition techniques. Work is underway in the Isotope Research Materials Laboratory (IRML) at ORNL to develop the techniques that will make the preparation of actinide targets up to 100 μg/cm 2 by ion beam sputtering a routinely available service from IRML. The preparation of the actinide material in a form suitable for sputtering is a key to this technique, as is designing a sputtering system that allows the flexibility required for custom-ordered target production. At present, development work is being conducted on low-activity actinides in a bench-top system. The system will then be installed in a hood or glove box approved for radioactive materials handling where processing of radium, actinium, and plutonium isotopes among others will be performed.

  9. Ge quantum dot arrays grown by ultrahigh vacuum molecular-beam epitaxy on the Si(001) surface: nucleation, morphology, and CMOS compatibility.

    Science.gov (United States)

    Yuryev, Vladimir A; Arapkina, Larisa V

    2011-09-05

    Issues of morphology, nucleation, and growth of Ge cluster arrays deposited by ultrahigh vacuum molecular beam epitaxy on the Si(001) surface are considered. Difference in nucleation of quantum dots during Ge deposition at low (≲600°C) and high (≳600°C) temperatures is studied by high resolution scanning tunneling microscopy. The atomic models of growth of both species of Ge huts--pyramids and wedges-- are proposed. The growth cycle of Ge QD arrays at low temperatures is explored. A problem of lowering of the array formation temperature is discussed with the focus on CMOS compatibility of the entire process; a special attention is paid upon approaches to reduction of treatment temperature during the Si(001) surface pre-growth cleaning, which is at once a key and the highest-temperature phase of the Ge/Si(001) quantum dot dense array formation process. The temperature of the Si clean surface preparation, the final high-temperature step of which is, as a rule, carried out directly in the MBE chamber just before the structure deposition, determines the compatibility of formation process of Ge-QD-array based devices with the CMOS manufacturing cycle. Silicon surface hydrogenation at the final stage of its wet chemical etching during the preliminary cleaning is proposed as a possible way of efficient reduction of the Si wafer pre-growth annealing temperature.

  10. Ge quantum dot arrays grown by ultrahigh vacuum molecular-beam epitaxy on the Si(001 surface: nucleation, morphology, and CMOS compatibility

    Directory of Open Access Journals (Sweden)

    Yuryev Vladimir

    2011-01-01

    Full Text Available Abstract Issues of morphology, nucleation, and growth of Ge cluster arrays deposited by ultrahigh vacuum molecular beam epitaxy on the Si(001 surface are considered. Difference in nucleation of quantum dots during Ge deposition at low (≲600°C and high (≳600°C temperatures is studied by high resolution scanning tunneling microscopy. The atomic models of growth of both species of Ge huts--pyramids and wedges-- are proposed. The growth cycle of Ge QD arrays at low temperatures is explored. A problem of lowering of the array formation temperature is discussed with the focus on CMOS compatibility of the entire process; a special attention is paid upon approaches to reduction of treatment temperature during the Si(001 surface pre-growth cleaning, which is at once a key and the highest-temperature phase of the Ge/Si(001 quantum dot dense array formation process. The temperature of the Si clean surface preparation, the final high-temperature step of which is, as a rule, carried out directly in the MBE chamber just before the structure deposition, determines the compatibility of formation process of Ge-QD-array based devices with the CMOS manufacturing cycle. Silicon surface hydrogenation at the final stage of its wet chemical etching during the preliminary cleaning is proposed as a possible way of efficient reduction of the Si wafer pre-growth annealing temperature.

  11. Measurement of key resonances for the 24Al(p ,γ )25Si reaction rate using in-beam γ -ray spectroscopy

    Science.gov (United States)

    Longfellow, B.; Gade, A.; Brown, B. A.; Richter, W. A.; Bazin, D.; Bender, P. C.; Bowry, M.; Elman, B.; Lunderberg, E.; Weisshaar, D.; Williams, S. J.

    2018-05-01

    Energy levels and branching ratios for the rp-process nucleus 25Si were determined from the reactions 9Be(26Si,25Si)X and 9Be(25Al,25Si)X using in-beam γ -ray spectroscopy with both high-efficiency and high-resolution detector arrays. Proton-unbound states at 3695(14) and 3802(11) keV were identified and assigned tentative spins and parities based on comparison to theory and the mirror nucleus. The 24Al(p ,γ )25Si reaction rate was calculated using the experimental states and states from charge-dependent USDA and USDB shell-model calculations with downward shifts of the 1 s1 /2 proton orbital to account for the observed Thomas-Ehrman shift, leading to a factor of 10-100 increase in rate for the temperature region of 0.22 GK as compared to a previous calculation. These shifts may be applicable to neighboring nuclei, impacting the proton capture rates in this region of the chart.

  12. Development of nanometer resolution C-Band radio frequency beam position monitors in the Final Focus Test Beam

    Energy Technology Data Exchange (ETDEWEB)

    Slaton, T.; Mazaheri, G. [Stanford Univ., CA (US). Stanford Linear Accelerator Center; Shintake, T. [National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan)

    1998-08-01

    Using a 47 GeV electron beam, the Final Focus Test Beam (FFTB) produces vertical spot sizes around 70 nm. These small beam sizes introduce an excellent opportunity to develop and test high resolution Radio Frequency Beam Position Monitors (RF-BPMs). These BPMs are designed to measure pulse to pulse beam motion (jitter) at a theoretical resolution of approximately 1 nm. The beam induces a TM{sub 110} mode with an amplitude linearly proportional to its charge and displacement from the BPM's (cylindrical cavity) axis. The C-band (5,712 MHz) TM{sub 110} signal is processed and converted into beam position for use by the Stanford Linear Collider (SLC) control system. Presented are the experimental procedures, acquisition, and analysis of data demonstrating resolution of jitter near 25 nm. With the design of future e{sup +}e{sup -} linear colliders requiring spot sizes close to 3 nm, understanding and developing RF-BPMs will be essential in resolving and controlling jitter.

  13. Plastic relaxation of GeSi/Si(001) films grown by molecular-beam epitaxy in the presence of the Sb surfactant

    International Nuclear Information System (INIS)

    Bolkhovityanov, Yu. B.; Deryabin, A. S.; Gutakovskii, A. K.; Kolesnikov, A. V.; Sokolov, L. V.

    2007-01-01

    Plastically relaxed GeSi films with the Ge fraction equal to 0.29-0.42 and thickness as large as 0.5 μm were grown on Si (001) substrates using the low-temperature (350 deg. C) buffer Si layer and Sb as a surfactant. It is shown that introduction of Sb that smoothens the film surface at the stage of pseudomorphic growth lowers the density of threading dislocations in the plastically relaxed heterostructure by 1-1.5 orders of magnitude and also reduces the final roughness of the surface. The root-mean-square value of roughness smaller than 1 nm was obtained for a film with the Ge content of 0.29 and the density of threading dislocations of about 10 6 cm -2 . It is assumed that the effect of surfactant is based on the fact that the activity of surface sources of dislocations is reduced in the presence of Sb

  14. Thermal cyclic oxidation behavior of the developed compositionally gradient graphite material of SiC/C in air environment

    International Nuclear Information System (INIS)

    Nakano, Junichi; Fujii, Kimio; Shindo, Masami

    1993-08-01

    For the developed compositionally gradient graphite material composed of surface SiC coating layer, middle SiC/C layer and graphite matrix, the thermal cyclic oxidation test was performed together with two kinds of the SiC coated graphite materials in air environment. It was made clear that the developed material exhibited high performance under severe thermal cyclic condition independent of the morphology of middle SiC/C layers and had the longer time or the more cycle margins from crack initiation to failure for surface SiC coating layer compared with the SiC coated graphite materials. (author)

  15. Simulation of the development and interaction of instabilities in a relativistic electron beam under variation of the beam wall thickness

    Energy Technology Data Exchange (ETDEWEB)

    Badarin, A. A.; Kurkin, S. A. [Saratov State University (Russian Federation); Koronovskii, A. A. [Yuri Gagarin State Technical University (Russian Federation); Rak, A. O. [Belorussian State University of Informatics and Radioelectronics (Belarus); Hramov, A. E., E-mail: hramovae@gmail.com [Saratov State University (Russian Federation)

    2017-03-15

    The development and interaction of Bursian and diocotron instabilities in an annular relativistic electron beam propagating in a cylindrical drift chamber are investigated analytically and numerically as functions of the beam wall thickness and the magnitude of the external uniform magnetic field. It is found that the interaction of instabilities results in the formation of a virtual cathode with a complicated rotating helical structure and several reflection regions (electron bunches) in the azimuthal direction. It is shown that the number of electron bunches in the azimuthal direction increases with decreasing beam wall thickness and depends in a complicated manner on the magnitude of the external magnetic field.

  16. The interaction of C60 on Si(111 7x7 studied by Supersonic Molecular Beams: interplay between precursor kinetic energy and substrate temperature in surface activated processes.

    Directory of Open Access Journals (Sweden)

    Lucrezia eAversa

    2015-06-01

    Full Text Available Buckminsterfullerene (C60 is a molecule fully formed of carbon that can be used, owing to its electronic and mechanical properties, as clean precursor for the growth of carbon-based materials, ranging from -conjugated systems (graphenes to synthesized species, e.g. carbides such as silicon carbide (SiC. To this goal, C60 cage rupture is the main physical process that triggers material growth. Cage breaking can be obtained either thermally by heating up the substrate to high temperatures (630°C, after C60 physisorption, or kinetically by using Supersonic Molecular Beam Epitaxy (SuMBE techniques. In this work, aiming at demonstrating the growth of SiC thin films by C60 supersonic beams, we present the experimental investigation of C60 impacts on Si(111 7x7 kept at 500°C for translational kinetic energies ranging from 18 to 30 eV. The attained kinetically activated synthesis of SiC submonolayer films is probed by in-situ surface electron spectroscopies (XPS and UPS. Furthermore, in these experimental conditions the C60-Si(111 7×7 collision has been studied by computer simulations based on a tight-binding approximation to Density Functional Theory, DFT. Our theoretical and experimental findings point towards a kinetically driven growth of SiC on Si, where C60 precursor kinetic energy plays a crucial role, while temperature is relevant only after cage rupture to enhance Si and carbon reactivity. In particular, we observe a counterintuitive effect in which for low kinetic energy (below 22 eV, C60 bounces back without breaking more effectively at high temperature due to energy transfer from excited phonons. At higher kinetic energy (22 < K < 30 eV, for which cage rupture occurs, temperature enhances reactivity without playing a major role in the cage break. These results are in good agreement with ab-initio molecular dynamics simulations. SuMBE is thus a technique able to drive materials growth at low temperature regime.

  17. Development of a Beam Trajectory Monitoring System Using e+/e- Pair Production Events

    Science.gov (United States)

    Kimura, Shota; Emoto, Yusaku; Fujihara, Kento; Ito, Hiroshi; Kawai, Hideyuki; Kobayashi, Atsushi; Mizuno, Takahiro

    2018-01-01

    In particle therapy, it is important to monitor the Bragg-peak position. It was simulated by GEANT4 Monte Carlo Simulation Code that the distribution of secondary generated gamma rays on the carbon beam therapy and the proton beam therapy. This simulation shows that gamma rays whose energy is 10 MeV or more are intensively generated at the Bragg-peak position. We are developing the system to monitor the Bragg-peak position which can measure pair production events occurred in the detector by gamma rays from irradiation points. The momentum direction of the gamma ray can be determined by measuring passing points and energy of e+ and e- generated by pair production. This system has 5 parts. The first is the conversion part. This part consists of several layers. Each layer is composed of a La-GPS ((Gd0.75La0.24Ce0.01)2Si2O7) scintillator plate and wavelength-shifting fibre (WLSF) sheets. The scintillator plate is sandwiched between sheets, where the directions of the sheets are in orthogonally x and y directions. In this part, gamma rays are converted to e+ e- pairs and the position where the conversion occured is determined. The second is the tracking part. This part consists of 2 layers of scintillating fibre tracker. Each layer has 6 scintillating fibre sheets for x, x', u, u', v, and v'. The third is the energy measurement part. It measures the energy of e+ and e- by scintillator array and Silicon Photomultipliers. The fourth is the veto counter for bremsstrahlung gamma rays from e+ and e-. The fifth is the beam monitor. By experiment, the number of photoelectrons of La-GPS with a WLSF (B-3(300)MJ, Kuraray) sheet and scintillating fibre (SCSF-78, Kuraray) when charged particle passed was measured as 9.7 and 7.6 respectively.

  18. Development of a Beam Trajectory Monitoring System Using e+/e− Pair Production Events

    Directory of Open Access Journals (Sweden)

    KIMURA Shota

    2018-01-01

    Full Text Available In particle therapy, it is important to monitor the Bragg-peak position. It was simulated by GEANT4 Monte Carlo Simulation Code that the distribution of secondary generated gamma rays on the carbon beam therapy and the proton beam therapy. This simulation shows that gamma rays whose energy is 10 MeV or more are intensively generated at the Bragg-peak position. We are developing the system to monitor the Bragg-peak position which can measure pair production events occurred in the detector by gamma rays from irradiation points. The momentum direction of the gamma ray can be determined by measuring passing points and energy of e+ and e− generated by pair production. This system has 5 parts. The first is the conversion part. This part consists of several layers. Each layer is composed of a La-GPS ((Gd0.75La0.24Ce0.012Si2O7 scintillator plate and wavelength-shifting fibre (WLSF sheets. The scintillator plate is sandwiched between sheets, where the directions of the sheets are in orthogonally x and y directions. In this part, gamma rays are converted to e+ e- pairs and the position where the conversion occured is determined. The second is the tracking part. This part consists of 2 layers of scintillating fibre tracker. Each layer has 6 scintillating fibre sheets for x, x’, u, u’, v, and v’. The third is the energy measurement part. It measures the energy of e+ and e− by scintillator array and Silicon Photomultipliers. The fourth is the veto counter for bremsstrahlung gamma rays from e+ and e-. The fifth is the beam monitor. By experiment, the number of photoelectrons of La-GPS with a WLSF (B-3(300MJ, Kuraray sheet and scintillating fibre (SCSF-78, Kuraray when charged particle passed was measured as 9.7 and 7.6 respectively.

  19. Molecular beam electric deflection of the tetrahalides CF4, CCl4, SiF4, SiCl4, GeCl4, TiF4, TiCl4, VF4, and VCl4

    International Nuclear Information System (INIS)

    Muenter, A.A.; Dyke, T.R.; Falconer, W.E.; Klemperer, W.

    1975-01-01

    Using molecular beam electric deflection, the temperature dependence of polar behavior has been studied for the molecules CF 4 , CCl 4 , SiF 4 , SiCl 4 , GeCl 4 , TiF 4 TiCl 4 , VF 4 , VF 4 , and VCl 4 . A number of these molecules show polar behavior consistent with a vibrationally induced dipole moment for states with one or both of the triply degenerate vibrations excited. In four of the tetrachloride species, the presence of a vibrationally induced dipole moment was confirmed by the change in polar behavior with isotopic substituion of the Cl atoms. The deflection behavior of the transition metal tetrahalides varied from nonpolar in VCl 4 to very polar in TiF 4

  20. SiO mass spectrometry and Si-2p photoemission spectroscopy for the study of oxidation reaction dynamics of Si(001) surface by supersonic O sub 2 molecular beams under 1000K

    CERN Document Server

    Teraoka, Y; Moritani, K

    2003-01-01

    The Si sup 1 sup 8 O desorption yield was measured in the Si(001) surface temperature region from 900K to 1300K at the sup 1 sup 8 O sub 2 incident energies of 0.7eV, 2.2eV and 3.3eV. The Si sup 1 sup 8 O desorption yield in a surface temperature region higher than 1000K increased with increasing incident energy, indicating the incident-energy-induced oxidation and the variation of angular distribution of Si sup 1 sup 8 O desorption. Inversely, the Si sup 1 sup 8 O desorption yield decreased with increasing incident energy in the region from 900K to 1000K, indicating the coexistence of the passive and the active oxidation. In order to clarify the reaction mechanisms of the later phenomenon, real-time in-situ Si-2p photoemission spectroscopy has been performed. The obtained Si-2p spectra showed the variation of the oxide-nuclei quality from the sub-oxide-rich structure to the SiO sub 2 -rich structure. The formation of the SiO sub 2 structure suppresses the SiO desorption due to the enhanced O sub 2 sticking a...

  1. Influence of copper content on microstructure development of AlSi9Cu3 alloy

    Directory of Open Access Journals (Sweden)

    Brodarac Zovko Z.

    2014-01-01

    Full Text Available Microstructure development and possible interaction of present elements have been determined in charge material of EN AlSi9Cu3 quality. Literature review enables prediction of solidification sequence. Modelling of equilibrium phase diagram for examined chemical composition has been performed, which enables determination of equilibrium solidification sequence. Microstructural investigation indicated distribution and morphology of particular phase. Metallographic analysis tools enable exact determination of microstructural constituents: matrix αAl, eutectic αAl+βSi, iron base intermetallic phase - Al5FeSi, Alx(Fe,MnyCuuSiw and/or Alx(Fe,MnyMgzCuuSiw and copper base phases in ternary eutectic morphology Al-Al2Cu-Si and in complex intermetallic ramified morphology Alx(Fe,MnyMgzSiuCuw. Microstructure development examination reveals potential differences due to copper content which is prerequisite for high values of final mechanical, physical and technological properties of cast products.

  2. The development of SiC whisker fabrication technology for nuclear applications

    International Nuclear Information System (INIS)

    Kang, Thae Khapp; Kuk, Il Hiun; Kim, Chang Kyu; Lee, Jae Chun; Lee, Ho Jin; Park, Soon Dong; Im, Gyeong Soo

    1991-02-01

    Some important experiments for whisker growth reactions, fabrication processes, and experiments for fabricarion of whisker reinforced composites have been performed. In order to investigate growth reaction of SiC whiskers, a conventional carbothermic reaction was tested. Based on the results of carbothermic process, a new process called silicothermic reaction was planned and some basic experiments were performed. Reaction characteristics of silicon monoxide, core material for SiC whisker growth in both of the reactions were investigated for basic data. Additionally, a hydrofluoric acid leaching process was tested for developing SiC whisker recovery process, and powder metallurgy process and melt sqeeze process were tried to develop aluminum-SiC whisker composites. (Author)

  3. Development of compact low energy election beam accelerator

    International Nuclear Information System (INIS)

    Katsura, Ichiro

    1996-01-01

    Sumitomo Heavy Industries has developed new compact accelerator jointly with its affiliated company RPC industries and some of which have already been in use in industries. Named WIPL, or WIP, which stands for Wire Ion Plasma, this accelerator is almost half the size of existing accelerators yet with performance as high as well enough to cope with industrial requirements. Background of our determination to develop such accelerator was that there prevails fairly good numbers of small laboratory units but only small numbers of production machines are in use. The main reason which brought such environment was that those production units were husky and costly. To overcome such problem and to turn situation in favor we launched the development programme and eventually succeeded to complete WIPL. Unique feature of WIPL was materialized by adopting special method of generating electrons. Unlike existing accelerators which use heated filaments WIPL utilizes the system using electron emission by bombardment of cathode plate by helium ions as electron source. Electrons are to be generated in following manner. 1) Thin helium gas is introduced in plasma chamber in which wire(s) for applying electric power. When power is supplied helium gas is turned into helium plasma by electric field. 2) Being energized by separate high voltage power source cathode plate is charged minus simultaneously. 3) Plus charged helium ions in plasma are then accelerated toward cathode plate and hit the surface. 4) Cathode plate emits electrons by bombardment and emitted electrons are compelled by the field and accelerated to the direction which helium ion came. Since such system no longer requires insulated transformers and control system for controlling electron beam current used in filament type machines equipment becomes remarkably small and economical. We really hope that this machine is accepted widely and contributes for exploiting the new horizon of electron beam market. (author)

  4. The development of chemically vapor deposited mullite coatings for the corrosion protection of SiC

    Energy Technology Data Exchange (ETDEWEB)

    Auger, M.; Hou, P.; Sengupta, A.; Basu, S.; Sarin, V. [Boston Univ., MA (United States)

    1998-05-01

    Crystalline mullite coatings have been chemically vapor deposited onto SiC substrates to enhance the corrosion and oxidation resistance of the substrate. Current research has been divided into three distinct areas: (1) Development of the deposition processing conditions for increased control over coating`s growth rate, microstructure, and morphology; (2) Analysis of the coating`s crystal structure and stability; (3) The corrosion resistance of the CVD mullite coating on SiC.

  5. Development of Universal Controller Architecture for SiC Based Power Electronic Building Blocks

    Science.gov (United States)

    2017-10-30

    SiC Based Power Electronic Building Blocks Award Number Title of Research 30 October 2017 SUBMITTED BY D R. HERBERT L. G INN, Pl DEPT. OF...Naval Research , Philadelphia PA, Aug. 2017. • Ginn, H.L. Bakos J., "Development of Universal Controller Architecture for SiC Based Power Electronic...Controller Implementation for MMC Converters", Workshop on Control Architectures for Modular Power Conversion Systems, Office of Naval Research , Arlington VA

  6. Development of nano SiO2 incorporated nano zinc phosphate coatings on mild steel

    International Nuclear Information System (INIS)

    Tamilselvi, M.; Kamaraj, P.; Arthanareeswari, M.; Devikala, S.; Selvi, J. Arockia

    2015-01-01

    Highlights: • Nano SiO 2 incorporated nano zinc phosphate coating on mild steel was developed. • Coatings showed enhanced corrosion resistance. • The nano SiO 2 is adsorbed on mild steel surface and become nucleation sites. • The nano SiO 2 accelerates the phosphating process. - Abstract: This paper reports the development of nano SiO 2 incorporated nano zinc phosphate coatings on mild steel at low temperature for achieving better corrosion protection. A new formulation of phosphating bath at low temperature with nano SiO 2 was attempted to explore the possibilities of development of nano zinc phosphate coatings on mild steel with improved corrosion resistance. The coatings developed were studied by Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDX), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Electrochemical measurements. Significant variation in the coating weight, morphology and corrosion resistance was observed as nano SiO 2 concentrations varied from 0.5–4 g/L. The results showed that, the nano SiO 2 in the phosphating solution changed the initial potential of the interface between mild steel substrate and phosphating solution and reduce the activation energy of the phosphating process, increase the nucleation sites and yielded zinc phosphate coatings of higher coating weight, greater surface coverage and enhanced corrosion resistance. Better corrosion resistance was observed for coatings derived from phosphating bath containing 1.5 g/L nano SiO 2 . The new formulation reported in the present study was free from Ni or Mn salts and had very low concentration of sodium nitrite (0.4 g/L) as accelerator

  7. Mechanically reinforced glass beams

    DEFF Research Database (Denmark)

    Nielsen, Jens Henrik; Olesen, John Forbes

    2007-01-01

    laminated float glass beam is constructed and tested in four-point bending. The beam consist of 4 layers of glass laminated together with a slack steel band glued onto the bottom face of the beam. The glass parts of the tested beams are \\SI{1700}{mm} long and \\SI{100}{mm} high, and the total width of one...

  8. IOP Latest R&D news and beam test performance of the highly granular SiW-ECAL technological prototype for the ILC

    CERN Document Server

    Irles, Adrián

    2018-02-22

    High precision physics at future colliders as the International Linear Collider (ILC) require unprecedented high precision in the determination of the energy of final state particles. The needed precision will be achieved thanks to the Particle Flow algorithms (PF) which require highly granular and hermetic calorimeters systems. The physical proof of concept of the PF was performed in the previous campaign of beam tests of physic prototypes within the CALICE collaboration. One of these prototypes was the physics prototype of the Silicon-Tungsten Electromagnetic Calorimeter (SiW-ECAL) for the International Large Detector at the ILC. In this document we present the latest nes on R&D of the next generation prototype, the technological prototype with fully embedded very front-end (VFE) electronics, of the SiW-ECAL. Special emphasis is given to the presentation and discussion of the first results from the beam test done at DESY in June 2017. The physics program for such beam test consisted in the calibration a...

  9. Ion sources development at GANIL for radioactive beams and high charge state ions

    International Nuclear Information System (INIS)

    Leroy, R.; Barue, C.; Canet, C.; Dupuis, M.; Flambard, J.L.; Gaubert, G.; Gibouin, S.; Huguet, Y.; Jardin, P.; Lecesne, N.; Leherissier, P.; Lemagnen, F.; Pacquet, J.Y.; Pellemoine-Landre, F.; Rataud, J.P.; Saint-Laurent, M.G.; Villari, A.C.C.; Maunoury, L.

    2001-01-01

    The GANIL laboratory has in charge the production of ion beams for nuclear and non nuclear physics. This article reviews the last developments that are underway in the fields of radioactive ion beam production, increase of the metallic ion intensities and production of highly charges ion beams. (authors)

  10. Development of high current beam ns pulsed system

    CERN Document Server

    Shen Guan Ren; Gao Fu; Guan Xia Ling; LiuNaiYi

    2001-01-01

    The development of high current beam ns pulsed system of CPNG and its characteristic, main technological performance and application are introduced. Firstly, important parameters of the system are calculated using theoretical model, the design requirements of some important parts are understood. Some mistakes in physics conception are corrected. Second, the chopper is designed for parallel plate deflector, chopping aperture and sine wave voltage sweeping device. It is emphasized that the conception of parallel plate load impedance is the capacitance load, but not the 50 ohm load impedance. The dynamic capacitance value has been measured. The output emphasizes the output voltage amplitude, but not the output power for sweeping device. The display system of output sweeping voltage was set up and it is sure that the maximum output voltage(V-V) is >=4000 V. The klystron buncher are re-designed. It is emphasized to overcome difficulty of support high voltage electrode in the klystron and insulator of input sine wa...

  11. Development of polarized e+ beams for future linear colliders

    International Nuclear Information System (INIS)

    Chiba, M.; Hamatsu, R.; Endo, A.

    1995-01-01

    We have so far been carrying out systematic investigations to create polarized e + on the basis of two new methods. One method is to use β + decay of radioactive nuclei with short life-time produced with a proton cyclotron and the other method is to use e + e - pair creation from polarized γ beams made through backward Compton scattering of laser lights. Here we describe technical details on productions of polarized e + and measurements of the polarization. The experiments of producing polarized e + will soon start. Although the e + intensity is not sufficiently high, we will acquire lots of know-how for further development of polarized e + sources with high quality which will possibly be applied to future linear colliders. (author)

  12. Development of useful genetic resources by proton-beam irradiation

    International Nuclear Information System (INIS)

    Kim, In Gyu; Kim, Kug Chan; Park, Hyi Gook; Jung, Il Lae; Seo, Yong Won; Chang, Chul Seong; Kim, Jae Yoon; Ham, Jae Woong

    2005-08-01

    The aim of this study is to develop new, useful and high-valuable genetic resources through the overproduction of biodegradable plastics and the propagation of wheat using proton-beam irradiation. Useful host strain was isolated through the mutagenization of the Escherichia coli K-12 strain, followed by characterizing the genetic and physiological properties of the E. coli mutant strains. The selected E. coli mutant strain produced above 85g/L of PHB, showed above 99% of PHB intracellular content and spontaneously liberated intracellular PHB granules. Based on the results, the production cost of PHB has been estimated to approximately 2$/kg, leading effective cost-down. Investigated the propagation of wheat and its variation, a selectable criterion of wet pro of was established and genetic analysis of useful mutant was carried out

  13. Development of global data warehouse for beam diagnostics at SSRF

    International Nuclear Information System (INIS)

    Lai Longwei; Leng Yongbin; Yan Yingbing; Chen Zhichu

    2015-01-01

    The beam diagnostic system is adequate during the daily operation and machine study at the Shanghai Synchrotron Radiation Facility (SSRF). Without the effective event detecting mechanism, it is difficult to dump and analyze abnormal phenomena such as the global orbital disturbance, the malfunction of the BPM and the noise of the DCCT. The global beam diagnostic data warehouse was built in order to monitor the status of the accelerator and the beam instruments. The data warehouse was designed as a Soft IOC hosted on an independent server. Once abnormal phenomena happen it will be triggered and will store the relevant data for further analysis. The results show that the data warehouse can detect abnormal phenomena of the machine and the beam diagnostic system effectively, and can be used for calculating confidential indicators of the beam instruments. It provides an efficient tool for the improvement of the beam diagnostic system and accelerator. (authors)

  14. Pion beam development for the LAMPF biomedical project

    International Nuclear Information System (INIS)

    Paciotti, M.; Amols, H.; Bradbury, J.; Rivera, O.; Hogstrom, K.; Smith, A.; Inoue, H.; Laubacher, D.; Sandford, S.

    1979-01-01

    Common to both static and dynamic patient irradiations at the LAMPF linac is the problem of maintaining good quality control of beams form a secondary channel. A major contributor to therapy beam variation has been change in electron contamination due to the change in target geometry and proton beam steering. The electron variation problem is described and a solution is presented that has been realized as a result o a new target geometry that allows some control of the electron fraction

  15. Fusion reactor development using high power particle beams

    International Nuclear Information System (INIS)

    Ohara, Y.

    1990-01-01

    The present paper outlines major applications of the ion source/accelerator to fusion research and also addresses the present status and future plans for accelerator development. Applications of ion sources/accelerators for fusion research are discussed first, focusing on plasma heating, plasma current drive, plasma current profile control, and plasma diagnostics. The present status and future plan of ion sources/accelerators development are then described focusing on the features of existing and future tokamak equipment. Positive-ion-based NBI systems of 100 keV class have contributed to obtaining high temperature plasmas whose parameters are close to the fusion break-even condition. For the next tokamak fusion devices, a MeV class high power neutral beam injector, which will be used to obtain a steady state burning plasma, is considered to become the primary heating and current drive system. Development of such a system is a key to realize nuclear fusion reactor. It will be entirely indebted to the development of a MeV class high current negative deuterium ion source/accelerator. (N.K.)

  16. Structure-phase states evolution in Al-Si alloy under electron-beam treatment and high-cycle fatigue

    International Nuclear Information System (INIS)

    Konovalov, Sergey; Alsaraeva, Krestina; Gromov, Victor; Semina, Olga; Ivanov, Yurii

    2015-01-01

    By methods of scanning and transmission electron diffraction microscopy the analysis of structure-phase states and defect substructure of silumin subjected to high-intensity electron beam irradiation in various regimes and subsequent fatigue loading up to failure was carried out. It is revealed that the sources of fatigue microcracks are silicon plates of micron and submicron size are not soluble in electron beam processing. The possible reasons of the silumin fatigue life increase under electron-beam treatment are discussed

  17. Strong band edge luminescence from InN films grown on Si substrates by electron cyclotron resonance-assisted molecular beam epitaxy

    International Nuclear Information System (INIS)

    Yodo, Tokuo; Yona, Hiroaki; Ando, Hironori; Nosei, Daiki; Harada, Yoshiyuki

    2002-01-01

    We observed strong band edge luminescence at 8.5-200 K from 200-880 nm thick InN films grown on 10 nm thick InN buffer layers on Si(001) and Si(111) substrates by electron cyclotron resonance-assisted molecular beam epitaxy. The InN film on the Si(001) substrate exhibited strong band edge photoluminescence (PL) emission at 1.814 eV at 8.5 K, tentatively assigned as donor to acceptor pair [DAP (α-InN)] emission from wurtzite-InN (α-InN) crystal grains, while those on Si(111) showed other stronger band edge PL emissions at 1.880, 2.081 and 2.156 eV, tentatively assigned as donor bound exciton [D 0 X(α-InN)] from α-InN grains, DAP (β-InN) and D 0 X (β-InN) emissions from zinc blende-InN (β-InN) grains, respectively

  18. Development of hollow electron beams for proton and ion collimation

    CERN Document Server

    Stancari, G; Kuznetsov, G; Shiltsev, V; Still, D A; Valishev, A; Vorobiev, L G; Assmann, R; Kabantsev, A

    2012-01-01

    Magnetically confined hollow electron beams for controlled halo removal in high-energy colliders such as the Tevatron or the LHC may extend traditional collimation systems beyond the intensity limits imposed by tolerable material damage. They may also improve collimation performance by suppressing loss spikes due to beam jitter and by increasing capture efficiency. A hollow electron gun was designed and built. Its performance and stability were measured at the Fermilab test stand. The gun will be installed in one of the existing Tevatron electron lenses for preliminary tests of the hollow-beam collimator concept, addressing critical issues such as alignment and instabilities of the overlapping proton and electron beams.

  19. Development of hollow electron beams for proton and ion collimation

    CERN Document Server

    Stancari, G.; Kuznetsov, G.; Shiltsev, V.; Still, D.A.; Valishev, A.; Vorobiev, L.G.; Assmann, R.; Kabantsev, A.

    2010-01-01

    Magnetically confined hollow electron beams for controlled halo removal in high-energy colliders such as the Tevatron or the LHC may extend traditional collimation systems beyond the intensity limits imposed by tolerable material damage. They may also improve collimation performance by suppressing loss spikes due to beam jitter and by increasing capture efficiency. A hollow electron gun was designed and built. Its performance and stability were measured at the Fermilab test stand. The gun will be installed in one of the existing Tevatron electron lenses for preliminary tests of the hollow-beam collimator concept, addressing critical issues such as alignment and instabilities of the overlapping proton and electron beams

  20. Design and development of neutral beam module components

    International Nuclear Information System (INIS)

    Holl, P.M.; Bulmer, R.H.; Dilgard, L.W.; Horvath, J.A.; Molvik, A.W.; Porter, G.D.; Shearer, J.W.; Slack, D.S.; Colonias, J.S.

    1979-01-01

    The Mirror Fusion Test Facility (MFTF) injection system consists of twenty 20 keV start-up, and twenty-four 80 keV sustaining neutral beam source modules. The neutral beam modules are mounted in four clusters equally spaced around the waist of the vacuum vessel which contains the superconducting magnets. A module is defined here as an assembly consisting of a beam source and the interfacing components between that beam source and the vacuum chamber. Six major interfacing components are the subject of this paper. They are the magnetic shield, the neutralizer duct, the isolation valve, mounting gimbals, aiming bellows and actuators

  1. In situ observation of electron-beam-induced dewetting of CdSe thin film embedded in SiO2

    DEFF Research Database (Denmark)

    Fabrim, Zacarias Eduardo; Kjelstrup-Hansen, Jakob; Fichtner, Paulo F. P.

    In this work we show the dewetting process of the CdSe thin films induced by electron beam irradiation. A multilayer heterostructure of SiO2/CdSe/SiO2 was made by a magnetron sputtering process. A plan-view (PV) sample was irradiated with 200 kV electrons in the TEM with two current densities: 0.......33 A.cm2 and 1.0 A.cm2 and at 80 kV with 0.37 A.cm2. The dewetting of the CdSe film is inferred by a number of micrographs taken during the irradiation. The microstructural changes were analyzed under the assumption of being induced by ballistic collision effects in the absence of sample heating....

  2. H0 candidates from the decays Σ-p and Λpπ-, produced in heavy ion collisions Si beam on Pb target

    International Nuclear Information System (INIS)

    Longacre, R.S.

    1997-01-01

    There is considerable interest in searching for strange quark matter (strangelets). The lowest strangelet state is thought to be a six quark dibaryon singlet spin zero state called the H 0 predicted by R.L. Jaffe. The authors present H 0 candidate events, where H 0 (2210) is observed through the weak decay modes Σ - p and Λpπ - , produced in central heavy ion collisions with 14.6 x A Gev/c Si beam on Pb target. The lifetime is consistent with ∼4 cm cr in both channels approximately 1/3 of an H 0 (2210) which decays into Σ - p is produced per central Si Pb collision. The branching ratio between Λpπ - and Σ - p is around 11% ± 3%

  3. Characterization of GaN P-N Junction Grown on Si (111) Substrate by Plasma-assisted Molecular Beam Epitaxy

    International Nuclear Information System (INIS)

    Rosfariza Radzali; Rosfariza Radzali; Mohd Anas Ahmad; Zainuriah Hassan; Norzaini Zainal; Kwong, Y.F.; Woei, C.C.; Mohd Zaki Mohd Yusoff; Mohd Zaki Mohd Yusoff

    2011-01-01

    In this report, the growth of GaN pn junction on Si (111) substrate by plasma assisted molecular beam epitaxy (PAMBE) is presented. Doping of GaN p-n junction has been carried out using Si and Mg as n-type dopant and p-type dopants, respectively. The sample had been characterized by PL, Raman spectroscopy, HR-XRD and SEM. PL spectrum showed strong band edge emission of GaN at ∼364 nm, indicating good quality of the sample. The image of SEM cross section of the sample showed sharp interfaces. The presence of peak ∼657 cm -1 in Raman measurement exhibited successful doping of Mg in the sample. (author)

  4. Characterization of vacancy-type defects induced by the implantation of Se and Si ions into GaAs by a slow positron beam

    International Nuclear Information System (INIS)

    Fujii, Satoshi; Shikata, Shinichi; Wei Long; Tanigawa, Shoichiro.

    1992-01-01

    Variable-energy (0-30keV) positron beam studies have been carried out on 200 keV Se-implanted and 70 keV Si-implanted GaAs specimens before and after annealing for electrical activation. From the measurements of Doppler broadened profiles as a function of incident positron energy, it was found that vacancy clusters with high concentration were introduced in the annealed specimen after Se implantation. From the parallel measurement of electrical characteristics, a higher activation efficiency was found for the higher concentration of vacancy clusters. That fact implies that electrons supplied by the activation of Se also convert the charge state of As vacancies from positive to negative. In contrast, no vacancy clusters were introduced in the Si-implanted GaAs. (author)

  5. Construction and beam-tests of silicon-tungsten and scintillator-SiPM modules for the CMS High Granularity Calorimeter for HL-LHC

    CERN Document Server

    Chang, Yung-wei

    2018-01-01

    A High Granularity Calorimeter (HGCAL) is being designed to replace the existing endcap calorimeters in CMS for the HL-LHC era. It features unprecedented transverse and longitudinal segmentation for both electromagnetic (ECAL) and hadronic (HCAL) compartments, with silicon sensors being chosen for the high-pseudorapidity regions due to their radiation tolerance. The remainder of the HGCAL, in the lower radiation environment, will use plastic scintillator with on-tile SiPM readout. Prototype hexagonal silicon modules, featuring a new Skiroc2-CMS front-end chip, together with a modified version of the scintillator-SiPM CALICE AHCAL, have been built and tested in beams at CERN in 2017. In this poster, we present measurements of noise, calibration, shower shapes and performance with electrons, pions and muons.

  6. Stress evolution of GaN/AlN heterostructure grown on 6H-SiC substrate by plasma assisted molecular beam epitaxy

    Science.gov (United States)

    Agrawal, M.; Ravikiran, L.; Dharmarasu, N.; Radhakrishnan, K.; Karthikeyan, G. S.; Zheng, Y.

    2017-01-01

    The stress evolution of GaN/AlN heterostructure grown on 6H-SiC substrate by plasma assisted molecular beam epitaxy (PA-MBE) has been studied. AlN nucleation layer and GaN layer were grown as a function of III/V ratio. GaN/AlN structure is found to form buried cracks when AlN is grown in the intermediate growth regime(III/V˜1)and GaN is grown under N-rich growth regime (III/VHEMT) heterostructure was demonstrated on 2-inch SiC that showed good two dimensional electron gas (2DEG) properties with a sheet resistance of 480 Ω/sq, mobility of 1280 cm2/V.s and sheet carrier density of 1×1013 cm-2.

  7. Impact of growth and annealing conditions on the parameters of Ge/Si(001) relaxed layers grown by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Yurasov, D. V., E-mail: Inquisitor@ipm.sci-nnov.ru [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Bobrov, A. I. [Lobachevsky State University of Nizhny Novgorod (Russian Federation); Daniltsev, V. M.; Novikov, A. V. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Pavlov, D. A. [Lobachevsky State University of Nizhny Novgorod (Russian Federation); Skorokhodov, E. V.; Shaleev, M. V.; Yunin, P. A. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation)

    2015-11-15

    Influence of the Ge layer thickness and annealing conditions on the parameters of relaxed Ge/Si(001) layers grown by molecular beam epitaxy via two-stage growth is investigated. The dependences of the threading dislocation density and surface roughness on the Ge layer thickness, annealing temperature and time, and the presence of a hydrogen atmosphere are obtained. As a result of optimization of the growth and annealing conditions, relaxed Ge/Si(001) layers which are thinner than 1 μm with a low threading dislocation density on the order of 10{sup 7} cm{sup –2} and a root mean square roughness of less than 1 nm are obtained.

  8. Molecular-beam epitaxial growth of insulating AlN on surface-controlled 6H-SiC substrate by HCl gas etching

    International Nuclear Information System (INIS)

    Onojima, Norio; Suda, Jun; Matsunami, Hiroyuki

    2002-01-01

    Insulating AlN layers were grown on surface-controlled 6H-SiC subtrates by molecular-beam epitaxy (MBE) using elemental Al and rf plasma-excited nitrogen (N*). HCl gas etching was introduced as an effective pretreatment method of substrate for MBE growth of AlN. 6H-SiC substrates pretreated by HCl gas etching had no surface polishing scratches and an atomically flat surface. In addition, evident ( 3 √x 3 √)R30 deg. surface reconstruction was observed even before thermal cleaning. AlN layers grown on this substrate had no defects related to surface polishing scratches and excellent insulating characteristics

  9. Proton beam micromachining on strippable aqueous base developable negative resist

    International Nuclear Information System (INIS)

    Rajta, I.; Uzonyi, I.; Baradacs, E.; Chatzichristidi, M.; Raptis, I.; Valamontes, E.S.

    2004-01-01

    Complete text of publication follows. Proton Beam Micromachining (PBM, also known as P-beam writing), a novel direct- write process for the production of 3D microstructures, can be used to make multilevel structures in a single layer of resist by varying the ion energy. The interaction between the bombarding ions and the target material is mainly ionization, and very few ions suffer high angle nuclear collisions, therefore structures made with PBM have smooth near vertical side walls. The most commony applied resists in PBM are the positive, conventional, polymethyl methacrylate (PMMA); and the negative, chemically amplified, SU-8 (Micro Chem Corp). SU-8 is an epoxy based resist suitable also for LIGA and UV-LIGA processes, it offers good sensitivity, good process latitude, very high aspect ratio and therefore it dominates in the high aspect ratio micromachining applications. SU-8 requires 30 nC/mm 2 fluence for PBM irradiations at 2 MeV protons. Its crosslinking chemistry is based on the eight epoxy rings in the polymer chain, which provide a very dense three dimensional network in the presence of suitably activated photo acid generators (PAGs) which is very difficult to be stripped away after development. Thus, stripping has to be assisted with plasma processes or with special liquid removers. Moreover, the SU-8 developer is organic, propylene glycol methyl ether acetate (PGMEA), and thus environmentally non-friendly. To overcome the SU-8 stripping limitations, design of a negative resist system where solubility change is not based solely on cross- linking but also on the differentiation of hydrophilicity between exposed and non-exposed areas is desirable. A new resist formulation, fulfilling the above specifications has been developed recently [1]. This formulation is based on a specific grade epoxy novolac (EP) polymer, a partially hydrogenated poly-4-hydroxy styrene (PHS) polymer, and an onium salt as photoacid generator (PAG), and has been successfully

  10. Electron-beam induced amorphization of stishovite: Silicon-coordination change observed using Si K-edge extended electron energy-loss fine structure

    Science.gov (United States)

    van Aken, P. A.; Sharp, T. G.; Seifert, F.

    modelling the amorphization as a decay process. Using the EXELFS data for amorphization, a new method is developed to derive the relative amounts of Si coordinations in high-pressure minerals with mixed coordination. For the radiation-induced amorphization process of stishovite the formation of a transitory structure with Si largely in fivefold coordination is deduced.

  11. Development of a relativistic Particle In Cell code PARTDYN for linear accelerator beam transport

    Energy Technology Data Exchange (ETDEWEB)

    Phadte, D., E-mail: deepraj@rrcat.gov.in [LPD, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India); Patidar, C.B.; Pal, M.K. [MAASD, Raja Ramanna Centre for Advanced Technology, Indore (India)

    2017-04-11

    A relativistic Particle In Cell (PIC) code PARTDYN is developed for the beam dynamics simulation of z-continuous and bunched beams. The code is implemented in MATLAB using its MEX functionality which allows both ease of development as well higher performance similar to a compiled language like C. The beam dynamics calculations carried out by the code are compared with analytical results and with other well developed codes like PARMELA and BEAMPATH. The effect of finite number of simulation particles on the emittance growth of intense beams has been studied. Corrections to the RF cavity field expressions were incorporated in the code so that the fields could be calculated correctly. The deviations of the beam dynamics results between PARTDYN and BEAMPATH for a cavity driven in zero-mode have been discussed. The beam dynamics studies of the Low Energy Beam Transport (LEBT) using PARTDYN have been presented.

  12. Ion beam synthesis of IrSi3 by implantation of 2 MeV Ir ions

    International Nuclear Information System (INIS)

    Sjoreen, T.P.; Chisholm, M.F.; Hinneberg, H.J.

    1992-11-01

    Formation of a buried IrSi 3 layer in (111) oriented Si by ion implantation and annealing has been studied at an implantation energy of 2 MeV for substrate temperatures of 450--550C. Rutherford backscattering (RBS), ion channeling and cross-sectional transmission electron microscopy showed that a buried epitaxial IrSi 3 layer is produced at 550C by implanting ≥ 3.4 x 10 17 Ir/cm 2 and subsequently annealing for 1 h at 1000C plus 5 h at 1100C. At a dose of 3.4 x 10 17 Ir/cm 2 , the thickness of the layer varied between 120 and 190 nm and many large IrSi 3 precipitates were present above and below the film. Increasing the dose to 4.4 x 10 17 Ir/cm 2 improved the layer uniformity at the expense of increased lattice damage in the overlying Si. RBS analysis of layer formation as a function of substrate temperature revealed the competition between the mechanisms for optimizing surface crystallinity vs. IrSi 3 layer formation. Little apparent substrate temperature dependence was evident in the as-implanted state but after annealing the crystallinity of the top Si layer was observed to deteriorate with increasing substrate temperature while the precipitate coarsening and coalescence improved

  13. Three-dimensional fabrication and characterisation of core-shell nano-columns using electron beam patterning of Ge-doped SiO2

    DEFF Research Database (Denmark)

    Gontard, Lionel C.; Jinschek, Joerg R.; Ou, Haiyan

    2012-01-01

    electron tomography. The results show that transformations in insulators that have been subjected to intense irradiation using charged particles can be studied directly in three dimensions. The fabricated structures include core-shell nano-columns, sputtered regions, voids, and clusters. (C) 2012 American......A focused electron beam in a scanning transmission electron microscope (STEM) is used to create arrays of core-shell structures in a specimen of amorphous SiO2 doped with Ge. The same electron microscope is then used to measure the changes that occurred in the specimen in three dimensions using...

  14. A SAP/Al-Mg-Si composite alloy for use as a proton beam window of a high-power proton accelerator

    International Nuclear Information System (INIS)

    Schroeder, G.; Ribbens, A.; Fiorini, P.; Giordano, G.

    1987-12-01

    A composite material consisting of a sintered aluminium product (SAP) core surrounded by an Al-Mg-Si alloy rim was studied with respect to its applicability as a stationary window inside a high-power proton beam. This paper summarizes the experimental procedures and results on both the composite material and individual SAP alloys in terms of materials preparation, microstructural characterization, leak tightness, deformation and burst behaviour, sensitivity to hydrogen embrittlement, and irradiation effects after helium preimplantation. Regarding any of these items, the material either proved good or showed only minor degradation. It is thus considered as promising for uses involving high thermomechanical load inside a high-radiation environment. (orig.)

  15. M3FT-16OR020202112 - Report on viability of hydrothermal corrosion resistant SiC/SiC Joint development

    Energy Technology Data Exchange (ETDEWEB)

    Katoh, Yutai [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Koyanagi, Takaaki [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kiggans Jr, James O. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Terrani, Kurt A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-06-30

    Hydrothermal corrosion of four types of the silicon carbide (SiC) to SiC plate joints were investigated under PWR and BWR relevant chemical conditions without irradiation. The joints were formed by metal diffusion bonding using molybdenum or titanium interlayer, reaction sintering using Ti-Si-C system, and SiC nanopowder sintering. Most of the formed joints withstood the corrosion tests for five weeks. The recession of the SiC substrates was limited. Based on the recession rate of the bonding layers, it was concluded that all the joints except for the molybdenum diffusion bond are promising under the reducing activity environments. The SiC nanopowder sintered joint was the most corrosion tolerant under the oxidizing activity environment among the four joints.

  16. Development of Raman-shifted probe laser beam for plasma ...

    Indian Academy of Sciences (India)

    laser chain that works on master oscillator-power amplifier configuration. It is .... beam is the same as that of the green beam and hence is matched to the input ... and Ramesh Chandra for the electronics support and wiring the power supply of.

  17. Beam dynamics studies to develop LHC luminosity model

    CERN Document Server

    Campogiani, Giovanna; Papaphilippou, Ioannis

    The thesis project aims at studying the different physical processes that are impacting luminosity, one of the key figures of merit of a collider operation. In particular the project focuses on extracting the most relevant parameters for the high-energy part of the model, which is mostly dominated by the beam-beam effect. LHC luminosity is degraded by parasitic collisions that reduce the beam lifetime and the particles stability in the collider. This instability is due to the non-linear effects of one beam electromagnetic field on another in the interaction region. Such parasitic encounters can be as many as 16 per interaction region, piling up to around 180 000 per second. Our goal is to study the evolution of charge density distribution in the beam, by tracking particles through a symplectic integrator that includes the beam-beam effect. In particular we want to obtain data on the halo particles, which are more sensible to instability, to better characterise the beam lifetime and monitor the luminosity evol...

  18. Beam diagnostic developments at the cooler synchrotron COSY-J ...

    Indian Academy of Sciences (India)

    To measure the beam quality in case of fast and slow ... Four internal target areas [1,2] are available for experiments with the circulating beam. ..... tors work at normal air condition which is a great advantage concerning costs and service.

  19. Development of an external beam nuclear microprobe on the Aglae facility of the Louvre museum

    Energy Technology Data Exchange (ETDEWEB)

    Calligaro, T.; Dran, J.-C. E-mail: dran@culture.fr; Ioannidou, E.; Moignard, B.; Pichon, L.; Salomon, J

    2000-03-01

    The external beam line of our facility has been recently equipped with the focusing system previously mounted on a classical nuclear microprobe. When using a 0.1 {mu}m thick Si{sub 3}N{sub 4} foil for the exit window and flowing helium on the sample under analysis, a beam spot as small as 10 {mu}m is attainable at a distance of 3 mm from the window. Elemental micromapping is performed by mechanical scanning. An electronic device has been designed which allows XY scanning by moving the sample under the beam by steps down to 0.1 {mu}m. Beam monitoring is carried out by means of the weak X-ray signal emitted by the exit foil and detected by a specially designed Si(Li) detector cooled by Peltier effect. The characteristics of external beams of protons and alpha particles are evaluated by means of resonance scanning and elemental mapping of a grid. An example of application is presented, dealing with elemental micro-mapping of inclusions in gemstones.

  20. Development of Advanced Environmental Barrier Coatings for SiC/SiC Ceramic Matrix Composites: Path Toward 2700 F Temperature Capability and Beyond

    Science.gov (United States)

    Zhu, Dongming; Harder, Bryan; Hurst, Janet B.; Good, Brian; Costa, Gustavo; Bhatt, Ramakrishna T.; Fox, Dennis S.

    2017-01-01

    Advanced environmental barrier coating systems for SiC-SiC Ceramic Matrix Composite (CMC) turbine and combustor hot section components are currently being developed to meet future turbine engine emission and performance goals. One of the significant coating development challenges is to achieve prime-reliant environmental barrier coating systems to meet the future 2700F EBC-CMC temperature stability and environmental durability requirements. This presentation will emphasize recent NASA environmental barrier coating system testing and down-selects, particularly the development path and properties towards 2700-3000F durability goals by using NASA hafnium-hafnia-rare earth-silicon-silicate composition EBC systems for the SiC-SiC CMC turbine component applications. Advanced hafnium-based compositions for enabling next generation EBC and CMCs capabilities towards ultra-high temperature ceramic coating systems will also be briefly mentioned.

  1. Effect of radiation damage on luminescence of erbium-implanted SiO sub 2 /Si studied by slow positron beam

    CERN Document Server

    Kawasuso, A; Hirata, K; Sekiguchi, T; Kobayashi, Y; Okada, S

    2000-01-01

    The effect of damage on 1.54 mu m luminescence for 30 keV-Er-implanted SiO sub 2 films has been studied by positron annihilation and cathodoluminescence. It was found that S-parameter in the films decreased after implantation, indicating the suppression of positronium formation. The luminescence appeared with the recovery of the S-parameter after 600 deg. C annealing. The intensity reached a maximum at 900 deg. C annealing whereas the S-parameter did not change significantly. It seems that most damages recover at 600 deg. C and thereafter Er ions transform to an optically active state at 900 deg. C.

  2. The Development of Si and SiGe Technologies for Microwave and Millimeter-Wave Integrated Circuits

    Science.gov (United States)

    Ponchak, George E.; Alterovitz, Samuel A.; Katehi, Linda P. B.; Bhattacharya, Pallab K.

    1997-01-01

    Historically, microwave technology was developed by military and space agencies from around the world to satisfy their unique radar, communication, and science applications. Throughout this development phase, the sole goal was to improve the performance of the microwave circuits and components comprising the systems. For example, power amplifiers with output powers of several watts over broad bandwidths, low noise amplifiers with noise figures as low as 3 dB at 94 GHz, stable oscillators with low noise characteristics and high output power, and electronically steerable antennas were required. In addition, the reliability of the systems had to be increased because of the high monetary and human cost if a failure occurred. To achieve these goals, industry, academia and the government agencies supporting them chose to develop technologies with the greatest possibility of surpassing the state of the art performance. Thus, Si, which was already widely used for digital circuits but had material characteristics that were perceived to limit its high frequency performance, was bypassed for a progression of devices starting with GaAs Metal Semiconductor Field Effect Transistors (MESFETs) and ending with InP Pseudomorphic High Electron Mobility Transistors (PHEMTs). For each new material or device structure, the electron mobility increased, and therefore, the high frequency characteristics of the device were improved. In addition, ultra small geometry lithographic processes were developed to reduce the gate length to 0.1 pm which further increases the cutoff frequency. The resulting devices had excellent performance through the millimeter-wave spectrum.

  3. Development and Optimisation of the SPS and LHC beam diagnostics based on Synchrotron Radiation monitors

    CERN Document Server

    AUTHOR|(CDS)2081364; Roncarolo, Federico

    Measuring the beam transverse emittance is fundamental in every accelerator, in particular for colliders, where its precise determination is essential to maximize the luminosity and thus the performance of the colliding beams.
 Synchrotron Radiation (SR) is a versatile tool for non-destructive beam diagnostics, since its characteristics are closely related to those of the source beam. At CERN, being the only available diagnostics at high beam intensity and energy, SR monitors are exploited as the proton beam size monitor of the two higher energy machines, the Super Proton Synchrotron (SPS) and the Large Hadron Collider (LHC). The thesis work documented in this report focused on the design, development, characterization and optimization of these beam size monitors. Such studies were based on a comprehensive set of theoretical calculations, numerical simulations and experiments. A powerful simulation tool has been developed combining conventional softwares for SR simulation and optics design, thus allowing t...

  4. Cathodoluminescence and ion beam analysis of ion-implanted combinatorial materials libraries on thermally grown SiO2

    International Nuclear Information System (INIS)

    Chen, C.-M.; Pan, H.C.; Zhu, D.Z.; Hu, J.; Li, M.Q.

    1999-01-01

    A method combining ion implantation and physical masking technique has been used to generate material libraries of various ion-implanted samples. Ion species of C, Ga, N, Pb, Sn, Y have been sequentially implanted to an SiO 2 film grown on a silicon wafer through combinatorial masks and consequently a library of 64 (2 6 ) samples is generated by 6 masking combinations. This approach offers rapid synthesis of samples with potential new compounds formed in the matrix, which may have specific luminescent properties. The depth-resolved cathodoluminescence (CL) measurements revealed some specific optical property in the samples correlated with implanted ion distributions. A marker-based technique is developed for the convenient location of sample site in the analysis of Rutherford backscattering spectrometry (RBS) and proton elastic scattering (PES), intended to characterize rapidly the ion implanted film libraries. These measurements demonstrate the power of nondestructively and rapidly characterizing composition and the inhomogeneity of the combinatorial film libraries, which may determine their physical properties

  5. Optical refractive index and static permittivity of mixed Zr-Si oxide thin films prepared by ion beam induced CVD

    Energy Technology Data Exchange (ETDEWEB)

    Ferrer, F.J. [Centro Nacional de Aceleradores, Av. Thomas A. Edison, 7, 41092 Sevilla (Spain)], E-mail: fjferrer@us.es; Frutos, F. [E.T.S. de Ingenieria Informatica, Avda. Reina Mercedes, s/n, 41012 Sevilla (Spain); Garcia-Lopez, J. [Centro Nacional de Aceleradores, Av. Thomas A. Edison, 7, 41092 Sevilla (Spain); Gonzalez-Elipe, A.R.; Yubero, F. [Insituto de Ciencia de Materiales de Sevilla, c/ Americo vespucio, no. 49, 41092 Sevilla (Spain)

    2007-12-03

    Mixed oxides Zr{sub x}Si{sub 1-x}O{sub 2} (0 < x < 1) thin films have been prepared at room temperature by decomposition of (CH{sub 3}CH{sub 2}O){sub 3}SiH and Zr[OC(CH{sub 3}){sub 3}]{sub 4} volatile precursors induced by mixtures of O{sub 2}{sup +} and Ar{sup +} ions. The films were flat and amorphous independently of the Si/Zr ratio and did not present phase segregation of the pure single oxides (SiO{sub 2} and ZrO{sub 2}). A 10-23 at.% of H and 1-5 at.% of C atoms remained incorporated in the films depending on the mixture ratio of the Si and Zr precursors and the composition of the bombarding gas used during the deposition process. These impurities are mainly forming hydroxyl and carboxylic groups. Optical refractive index and static permittivity of the films were determined by reflection NIR-Vis spectroscopy and C-V electrical characterization, respectively. It is found that the refractive index increases non-linearly from 1.45 to 2.10 as the Zr content in the thin films increases. The static permittivity also increases non-linearly from {approx} 4 for pure SiO{sub 2} to {approx} 15 for pure ZrO{sub 2}. Optical and electrical characteristics of the films are justified by their impurity content and the available theories.

  6. Development of a reusable beam profile analyzer for laser accelerated proton beams

    Energy Technology Data Exchange (ETDEWEB)

    Frydrych, Simon; Busold, Simon; Deppert, Oliver; Roth, Markus [Technische Univ. Darmstadt (Germany). Inst. fuer Kernphysik

    2013-07-01

    At the GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, proton beams are generated with the PHELIX laser system through target normal sheath acceleration (TNSA). Within 1 ps, 10{sup 13} protons are produced with an exponential energy spectrum up to 50 MeV. For characterisation, the spatial beam profile is currently detected by a stack of radiochromatic films (RCF). These are blued depending on the beam intensity. One disadvantage of RCFs is its one-time usability. Therefore, they shall be replaced by a scintillator array. To ensure the longest possible shelf life of this new detector, the scintillator material used must be very robust against radiation damage. Also a point of current research is the maximal amount of particles, which can be detected separately.

  7. Development of a Positive-readout Mouse Model of siRNA Pharmacodynamics

    Directory of Open Access Journals (Sweden)

    Mark Stevenson

    2013-01-01

    Full Text Available Development of RNAi-based therapeutics has the potential to revolutionize treatment options for a range of human diseases. However, as with gene therapy, a major barrier to progress is the lack of methods to achieve and measure efficient delivery for systemic administration. We have developed a positive-readout pharmacodynamic transgenic reporter mouse model allowing noninvasive real-time assessment of siRNA activity. The model combines a luciferase reporter gene under the control of regulatory elements from the lac operon of Escherichia coli. Introduction of siRNA targeting lac repressor results in increased luciferase expression in cells where siRNA is biologically active. Five founder luciferase-expressing and three founder Lac-expressing lines were generated and characterized. Mating of ubiquitously expressing luciferase and lac lines generated progeny in which luciferase expression was significantly reduced compared with the parental line. Administration of isopropyl β-D-1-thiogalactopyranoside either in drinking water or given intraperitoneally increased luciferase expression in eight of the mice examined, which fell rapidly when withdrawn. Intraperitoneal administration of siRNA targeting lac in combination with Lipofectamine 2000 resulted in increased luciferase expression in the liver while control nontargeting siRNA had no effect. We believe a sensitive positive readout pharmacodynamics reporter model will be of use to the research community in RNAi-based vector development.

  8. Methodology Development for SiC Sensor Signal Modelling in the Nuclear Reactor Radiation Environments

    International Nuclear Information System (INIS)

    Cetnar, J.; Krolikowski, I.P.

    2013-06-01

    This paper deals with SiC detector simulation methodology for signal formation by neutrons and induced secondary radiation as well as its inverse interpretation. The primary goal is to achieve the SiC capability of simultaneous spectroscopic measurements of neutrons and gamma-rays for which an appropriate methodology of the detector signal modelling and its interpretation must be adopted. The process of detector simulation is divided into two basically separate but actually interconnected sections. The first one is the forward simulation of detector signal formation in the field of the primary neutron and secondary radiations, whereas the second one is the inverse problem of finding a representation of the primary radiation, based on the measured detector signals. The applied methodology under development is based on the Monte Carlo description of radiation transport and analysis of the reactor physics. The methodology of SiC detector signal interpretation will be based on the existing experience in neutron metrology developed in the past for various neutron and gamma-ray detection systems. Since the novel sensors based on SiC are characterised by a new structure, yet to be finally designed, the methodology for particle spectroscopic fluence measurement must be developed while giving a productive feed back to the designing process of SiC sensor, in order to arrive at the best possible design. (authors)

  9. Nitridation effects of Si(1 1 1) substrate surface on InN nanorods grown by plasma-assisted molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Shan [Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074 (China); Tan, Jin, E-mail: jintan_cug@163.com [Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074 (China); Engineering Research Center of Nano-Geomaterials of Ministry of Education, China University of Geosciences, Wuhan 430074 (China); Li, Bin; Song, Hao; Wu, Zhengbo; Chen, Xin [Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074 (China)

    2015-02-05

    Graphical abstract: The morphology evolution of InN nanorods in samples (g)–(i). The alignment of InN nanorods is improved and the deviation angle distribution narrows down with increase in nitriding time. It suggests that extending the nitriding time can enhance the vertical orientation of InN nanorods. - Highlights: • InN nanorods were grown on surface nitrided Si(1 1 1) substrate using PAMBE system. • Nitridation of substrate surface has a strong effect on morphology of InN nanorods. • InN nanorods cannot be formed with 1 min nitridation of Si(1 1 1) substrate. • Increasing nitriding time will increase optimum growth temperature of InN nanorods. • Increasing nitriding time can enhance vertical orientation of InN nanorods. - Abstract: The InN nanorods were grown on Si(1 1 1) substrate by plasma-assisted molecular beam epitaxy (PAMBE) system, with a substrate nitridation process. The effect of nitriding time of Si(1 1 1) substrate on morphology, orientation and growth temperature of InN nanorods was characterized via scanning electron microscopy (SEM) and X-ray diffraction (XRD). The deviation angle of InN nanorods was measured to evaluate the alignment of arrays. The results showed that InN nanorods could not be formed with 1 min nitridation of Si(1 1 1) substrate, but they could be obtained again when the nitriding time was increased to more than 10 min. In order to get aligned InN nanorods, the growth temperature needed to increase with longer nitriding time. The vertical orientation of InN nanorods could be enhanced with increase in nitriding time. The influence of the substrate nitridation on the photoluminescence (PL) spectra of InN nanorods has been investigated.

  10. Structural properties of In0.53Ga0.47As epitaxial films grown on Si (111) substrates by molecular beam epitaxy

    International Nuclear Information System (INIS)

    Gao, Fangliang; Wen, Lei; Zhang, Xiaona; Guan, Yunfang; Li, Jingling; Zhang, Shuguang; Li, Guoqiang

    2015-01-01

    In 0.53 Ga 0.47 As epitaxial films are grown on 2-inch diameter Si (111) substrates by growing a low-temperature In 0.4 Ga 0.6 As buffer layer using molecular beam epitaxy. The effect of the buffer layer thickness on the as-grown In 0.53 Ga 0.47 As films is characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy and transmission electron microscopy (TEM). It is revealed that the crystalline quality and surface morphology of as-grown In 0.53 Ga 0.47 As epilayer are strongly affected by the thickness of the In 0.4 Ga 0.6 As buffer layer. From TEM investigation, we understand that the type and the distribution of dislocations of the buffer layer and the as-grown In 0.53 Ga 0.47 As film are different. We have demonstrated that the In 0.4 Ga 0.6 As buffer layer with a thickness of 12 nm can advantageously release the lattice mismatch stress between the In 0.53 Ga 0.47 As and Si substrate, ultimately leading to a high-quality In 0.53 Ga 0.47 As epitaxial film with low surface roughness. - Highlights: • We provide a simple approach to achieve high-quality In 0.53 Ga 0.47 As films on Si. • An appropriate thickness of In 0.4 Ga 0.6 As buffer layer can release mismatch strain. • High-quality In 0.53 Ga 0.47 As film is grown on Si using 12-nm-thick buffer layer. • Smooth surface In 0.53 Ga 0.47 As film is grown on Si using 12-nm-thick buffer layer

  11. Tasks for development of SiC/SiC composites as structural material in a fusion reactor

    International Nuclear Information System (INIS)

    Yamada, Reiji

    1997-01-01

    SiC/SiC composites are chosen for a structural material of blankets in DREAM Reactor that has been proposed as a power reactor by JAERI. The main requirements and the target values in the DREAM conceptual design were described, and compared to available experimental data. (author)

  12. Development of slow positron beam lines and applications

    Science.gov (United States)

    Mondal, Nagendra Nath

    2018-05-01

    A positron is an antiparticle of an electron that can be formed in diverse methods: natural or artificial β-decay process, fission and fusion reactions, and a pair production of electron-positron occurred in the reactor and the high energy accelerator centers. Usually a long-lifetime radio isotope is customized for the construction of a slow positron beam lines in many laboratories. The typical intensity of this beam depends upon the strength of the positron source, moderator efficiency, and guiding, pulsing, focusing and detecting systems. This article will review a few positron beam lines and their potential applications in research, especially in the Positronium Bose-Einstein Condensation.

  13. Isotope-beam modification of materials at eV energies

    International Nuclear Information System (INIS)

    Krug, C.; Radtke, C.; Stedile, F.C.; Baumvol, I.J.R.

    2001-01-01

    We developed a low energy ion beam deposition system for isotope-selective modification of materials. It consists of a conventional ion implanter (HVEE 500 kV) and an attachable deceleration system. 29 (N 2 ) + ion beams were used for the nitridation of Si(0 0 1) and the resulting 15 N retained doses and profiles were determined by narrow nuclear resonance profiling. 29 Si was deposited on amorphous carbon films on Si(0 0 1) and the doses evaluated by channeled α particle beams with detection of scattered α at grazing angles. 29 Si was also deposited on Si(0 0 1) and the resulting profiles determined by narrow nuclear resonance

  14. Development of a computerized tomographic system based on the FAN-BEAM technique

    International Nuclear Information System (INIS)

    Junqueira, M.M.; Santos, C.A.C.; Borges, J.C.

    1986-01-01

    The Nuclear Instrumentation Laboratory, at COPPE/UFRJ, concentrates its researches in the development of computerized tomographic systems, looking for applications in industrial and medical non destructive analysing techniques. In this work we have projected and constructed a tomographic prototype, based on the FAN-BEAM technique for irradiating the object under analysis. An algorithm previously developed to analyse parallel beams, was modified and adapted to the FAN-BEAM geometry. (Author) [pt

  15. Development of Simulink-Based SiC MOSFET Modeling Platform for Series Connected Devices

    DEFF Research Database (Denmark)

    Tsolaridis, Georgios; Ilves, Kalle; Reigosa, Paula Diaz

    2016-01-01

    A new MATLAB/Simulink-based modeling platform has been developed for SiC MOSFET power modules. The modeling platform describes the electrical behavior f a single 1.2 kV/ 350 A SiC MOSFET power module, as well as the series connection of two of them. A fast parameter initialization is followed...... by an optimization process to facilitate the extraction of the model’s parameters in a more automated way relying on a small number of experimental waveforms. Through extensive experimental work, it is shown that the model accurately predicts both static and dynamic performances. The series connection of two Si......C power modules has been investigated through the validation of the static and dynamic conditions. Thanks to the developed model, a better understanding of the challenges introduced by uneven voltage balance sharing among series connected devices is possible....

  16. Improving surface smoothness and photoluminescence of CdTe(1 1 1)A on Si(1 1 1) substrates grown by molecular beam epitaxy using Mn atoms

    International Nuclear Information System (INIS)

    Wang, Jyh-Shyang; Tsai, Yu-Hsuan; Chen, Chang-Wei; Dai, Zi-Yuan; Tong, Shih-Chang; Yang, Chu-Shou; Wu, Chih-Hung; Yuan, Chi-Tsu; Shen, Ji-Lin

    2014-01-01

    Highlights: • CdTe(1 1 1)A epilayers were grown on Si(1 1 1) substrates by molecular beam epitaxy. • We report an enhanced growth using Mn atoms. • The significant improvements in surface quality and optical properties were found. - Abstract: This work demonstrates an improvement of the molecular beam epitaxial growth of CdTe(1 1 1)A epilayer on Si(1 1 1) substrates using Mn atoms. The reflection high-energy electron diffraction patterns show that the involvement of some Mn atoms in the growth of CdTe(1 1 1)A is even more effective than the use of a buffer layer with a smooth surface for forming good CdTe(1 1 1)A epilayers. 10 K Photoluminescence spectra show that the incorporation of only 2% Mn significantly reduced the intensity of defect-related emissions and considerably increased the integral intensity of exciton-related emissions by a large factor of about 400

  17. Development of reaction-sintered SiC mirror for space-borne optics

    Science.gov (United States)

    Yui, Yukari Y.; Kimura, Toshiyoshi; Tange, Yoshio

    2017-11-01

    We are developing high-strength reaction-sintered silicon carbide (RS-SiC) mirror as one of the new promising candidates for large-diameter space-borne optics. In order to observe earth surface or atmosphere with high spatial resolution from geostationary orbit, larger diameter primary mirrors of 1-2 m are required. One of the difficult problems to be solved to realize such optical system is to obtain as flat mirror surface as possible that ensures imaging performance in infrared - visible - ultraviolet wavelength region. This means that homogeneous nano-order surface flatness/roughness is required for the mirror. The high-strength RS-SiC developed and manufactured by TOSHIBA is one of the most excellent and feasible candidates for such purpose. Small RS-SiC plane sample mirrors have been manufactured and basic physical parameters and optical performances of them have been measured. We show the current state of the art of the RS-SiC mirror and the feasibility of a large-diameter RS-SiC mirror for space-borne optics.

  18. Development of a Si-PM-based high-resolution PET system for small animals

    International Nuclear Information System (INIS)

    Yamamoto, Seiichi; Imaizumi, Masao; Watabe, Tadashi; Shimosegawa, Eku; Hatazawa, Jun; Watabe, Hiroshi; Kanai, Yasukazu

    2010-01-01

    A Geiger-mode avalanche photodiode (Si-PM) is a promising photodetector for PET, especially for use in a magnetic resonance imaging (MRI) system, because it has high gain and is less sensitive to a static magnetic field. We developed a Si-PM-based depth-of-interaction (DOI) PET system for small animals. Hamamatsu 4 x 4 Si-PM arrays (S11065-025P) were used for its detector blocks. Two types of LGSO scintillator of 0.75 mol% Ce (decay time: ∼45 ns; 1.1 mm x 1.2 mm x 5 mm) and 0.025 mol% Ce (decay time: ∼31 ns; 1.1 mm x 1.2 mm x 6 mm) were optically coupled in the DOI direction to form a DOI detector, arranged in a 11 x 9 matrix, and optically coupled to the Si-PM array. Pulse shape analysis was used for the DOI detection of these two types of LGSOs. Sixteen detector blocks were arranged in a 68 mm diameter ring to form the PET system. Spatial resolution was 1.6 mm FWHM and sensitivity was 0.6% at the center of the field of view. High-resolution mouse and rat images were successfully obtained using the PET system. We confirmed that the developed Si-PM-based PET system is promising for molecular imaging research.

  19. Development of a SiPM-based PET imaging system for small animals

    International Nuclear Information System (INIS)

    Lu, Yanye; Yang, Kun; Zhou, Kedi; Zhang, Qiushi; Pang, Bo; Ren, Qiushi

    2014-01-01

    Advances in small animal positron emission tomography (PET) imaging have been accelerated by many new technologies such as the successful incorporation of silicon photomultiplier (SiPM). In this paper, we have developed a compact, lightweight PET imaging system that is based on SiPM detectors for small animals imaging, which could be integrated into a multi-modality imaging system. This PET imaging system consists of a stationary detector gantry, a motor-controlled animal bed module, electronics modules, and power supply modules. The PET detector, which was designed as a multi-slice circular ring geometry of 27 discrete block detectors, is composed of a cerium doped lutetium–yttrium oxyorthosilicate (LYSO) scintillation crystal and SiPM arrays. The system has a 60 mm transaxial field of view (FOV) and a 26 mm axial FOV. Performance tests (e.g. spatial resolution, energy resolution, and sensitivity) and phantom and animal imaging studies were performed to evaluate the imaging performance of the PET imaging system. The performance tests and animal imaging results demonstrate the feasibility of an animal PET system based on SiPM detectors and indicate that SiPM detectors can be promising photodetectors in animal PET instrumentation development

  20. Development of a SiPM-based PET imaging system for small animals

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yanye [Department of Biomedicine and Engineering, College of Engineering, Peking University, Beijing 100871 (China); Yang, Kun, E-mail: yangkun9999@hotmail.com [Department of Control Technology and Instrumentation, College of Quality and Technical Supervision, Hebei University, Baoding, 071000 (China); Zhou, Kedi; Zhang, Qiushi; Pang, Bo [Department of Biomedicine and Engineering, College of Engineering, Peking University, Beijing 100871 (China); Ren, Qiushi, E-mail: renqsh@coe.pku.edu.cn [Department of Biomedicine and Engineering, College of Engineering, Peking University, Beijing 100871 (China)

    2014-04-11

    Advances in small animal positron emission tomography (PET) imaging have been accelerated by many new technologies such as the successful incorporation of silicon photomultiplier (SiPM). In this paper, we have developed a compact, lightweight PET imaging system that is based on SiPM detectors for small animals imaging, which could be integrated into a multi-modality imaging system. This PET imaging system consists of a stationary detector gantry, a motor-controlled animal bed module, electronics modules, and power supply modules. The PET detector, which was designed as a multi-slice circular ring geometry of 27 discrete block detectors, is composed of a cerium doped lutetium–yttrium oxyorthosilicate (LYSO) scintillation crystal and SiPM arrays. The system has a 60 mm transaxial field of view (FOV) and a 26 mm axial FOV. Performance tests (e.g. spatial resolution, energy resolution, and sensitivity) and phantom and animal imaging studies were performed to evaluate the imaging performance of the PET imaging system. The performance tests and animal imaging results demonstrate the feasibility of an animal PET system based on SiPM detectors and indicate that SiPM detectors can be promising photodetectors in animal PET instrumentation development.

  1. The european programme on negative ion beam development

    International Nuclear Information System (INIS)

    Pamela, J.; Hemsworth, R.; Jacquot, C.; Holmes, A.J.T.

    1991-01-01

    The European Programme on Negative Ion Beam development consists presently of three main tasks: (i) the DRAGON experiment starting at Culham, with the objective of accelerating 4 A of D - to 200 keV; (ii) the conceptual study of a 1 MV, 15 A power supply, conducted in european industry under the supervision of Cadarache; (iii) the design study of a 1MV, 4 A, deuterium test bed at Cadarache, conducted by the EURATOM-CEA Association (Cadarache) with support from the EURATOM-UKAEA association (Culham) and the FOM institute (Amsterdam). The conclusions of these three tasks are to be brought together during the first half of 1992, in order to prepare a proposal for a 1 MV, 4 A, deuterium test bed. Other experimental activities are being conducted in european laboratories, either directly related to the main programme (RF source and plasma neutralizer at Culham; discharge pulsing at Dublin and FOM-Amsterdam) or under separate contracts (energy recovery and cesium seeding at Cadarache)

  2. Understanding focused ion beam guided anodic alumina nanopore development

    International Nuclear Information System (INIS)

    Chen Bo; Lu, Kathy; Tian Zhipeng

    2011-01-01

    Graphical abstract: Display Omitted Highlights: → We study the effect of FIB patterning on pore evolution during anodization. → FIB patterned concaves with 1.5 nm depth can effectively guide nanopore growth. → The edge effect of FIB guided patterns causes nanopores to bend. → Anodization window is enlarged to 50-80 V for 150 nm interpore distance hexagonal arrays. - Abstract: Focused ion beam (FIB) patterning in combination with anodization has shown great promise in creating unique pore patterns. This work is aimed to understand the effect of the FIB patterned sites in guiding anodized pore development. Highly ordered porous anodic alumina has been created with the guidance of FIB created patterns on electropolished aluminum followed by oxalic acid anodization. Shallow concaves created by the FIB with only 1.5 nm depth can effectively guide the growth of ordered nanopore patterns. With the guidance of the FIB pattern, the anodization rate is much faster and the nanopore growth direction bends at the boundary of the FIB patterned and un-patterned regions. FIB patterning also enlarges the anodization window; ordered nanopore arrays with 150 nm interpore distances can be produced under an applied potential from 50 V to 80 V. The fundamental understanding of these unique processes is discussed.

  3. Electron beam weld parameter set development and cavity cost

    International Nuclear Information System (INIS)

    John Brawley; John Mammossor; Larry Philips

    1997-01-01

    Various methods have recently been considered for use in the cost-effective manufacturing of large numbers of niobium cavities. A method commonly assumed to be too expensive is the joining of half cells by electron beam welding (EBW), as has been done with multipurpose EBW equipment for producing small numbers of cavities at accelerator laboratories. The authors have begun to investigate the advantages that would be available if a single-purpose, task-specific EBW processing tool were used to produce cavities in a high-volume commercial-industrial context. For such a tool and context they have sought to define an EBW parameter set that is cost-effective not only in terms of per-cavity production cost, but also in terms of the minimization of quench-producing weld defects. That is, they define cavity cost-effectiveness to include both production and performance costs. For such an EBW parameter set, they have developed a set of ideal characteristics, produced and tested samples and a complete cavity, studied the weld-defect question, and obtained industrial estimates of cavity high-volume production costs. The investigation in ongoing. This paper reports preliminary findings

  4. The development of UK protocols for electron beam dosimetry

    International Nuclear Information System (INIS)

    Thwaites, D.I.

    1995-01-01

    The IPSM Electron Dosimetry Working Party has completed a new set of recommendations for clinical electron beam dosimetry to replace the 1985 Code of Practice and its 1992 addendum. The current approach takes account of the significant body of relevant work over the last ten years and adopts the best consistent set of physical data currently available. It is still an air-kerma based approach, but adopts the N D formalism. This means that single conversion/correction factors are no longer retained. The new Code of Practice is intended to provide a solid basis for clinical practice at present, and to allow confident assessment of the introduction of the direct absorbed dose calibration service for electrons, currently under development by NPL, when that is ready. The structure of the new Code is reviewed, with discussion of changes from the 1985 approach and of the physical data incorporated. In particular the changes for parallel plate chamber calibration and use are discussed. Points of similarity and difference to other international codes are noted and the doses measured using different codes are compared

  5. Development, Production and Testing of 4500 Beam Loss Monitors

    CERN Document Server

    Holzer, E B; Dehning, B; Ferioli, G; Grishin, V; Jimenez, T M; Koshelev, A; Kramer, Daniel; Larionov, A; Taborelli, M; Seleznev, V; Sleptsov, M; Sytin, A; Wevers, I

    2008-01-01

    Beam-loss monitoring (BLM) [1] is a key element in the LHC machine protection. 4250 nitrogen filled ionization chambers (IC) and 350 secondary emission monitors (SEM) have been manufactured and tested at the Institute for High Energy Physics (IHEP) in Protvino, Russia, following their development at CERN. Signal speed and robustness against aging were the main design criteria. Each monitor is permanently sealed inside a stainless-steel cylinder. The quality of the welding was a critical aspect during production. The SEMs are requested to hold a vacuum of $10^{-7}$ bar. Impurity levels from thermal and radiationinduced desorption should remain in the range of parts per million in the ICs. To avoid radiation aging (up to $2·10^{8}$ Gy in 20 years) production of the chambers followed strict UHV requirements. IHEP designed and built the UHV production stand. Due to the required dynamic range of $10^{8}$, the leakage current of the monitors has to stay below 2 pA. Several tests during and after production were ...

  6. Developments on positron scattering experiments including beam production and detection

    International Nuclear Information System (INIS)

    Selim, F.A.; Golovchenko, J.A.

    2001-01-01

    Positron scattering and channeling experiments require high quality (low emittance) beams. A new electrostatic optics system for extracting positrons from a moderator is presented. The system features improved efficiency of focusing and beam transport of moderated positrons emitted with angular spreads up to ± 30 , with good phase space characteristics. The presented optics also provides a high degree of freedom in controlling exit beam trajectories. The system has been installed in the LLNL Pelletron accelerator and showed great enhancement on the beam quality. On the detection side, image plates were used to measure the angular distributions of positrons transmitted through the gold crystals. The measurements demonstrate the advantages of image plates as quantitative position sensitive detectors for positrons. (orig.)

  7. Design and development of multi-megawatt beam dumps

    International Nuclear Information System (INIS)

    Haughian, J.M.; Cooper, W.S.; Paterson, J.A.

    1976-11-01

    The next generation of U.S. fusion experiments which includes TFTR, MFTF, and Doublet III, will utilize neutral-beam injection for plasma heating. TFTR, for example, desires 20 MW of 120-keV deuterium atoms in pulses of 0.5-sec duration. In order to meet these requirements, a 15-A, 120-keV, 0.5-sec pulse per minute module is presently under test at the neutral-beam test facility at the Lawrence Berkeley Laboratory. A 65-A, 120-keV, 0.5-sec module is under construction and is scheduled for assembly in April of this year. Some of the features of a calorimeter/beam dump that is presently being used in the testing and evaluation of these neutral beam sources are discussed

  8. Development of a Hard X-ray Beam Position Monitor for Insertion Device Beams at the APS

    Science.gov (United States)

    Decker, Glenn; Rosenbaum, Gerd; Singh, Om

    2006-11-01

    Long-term pointing stability requirements at the Advanced Photon Source (APS) are very stringent, at the level of 500 nanoradians peak-to-peak or better over a one-week time frame. Conventional rf beam position monitors (BPMs) close to the insertion device source points are incapable of assuring this level of stability, owing to mechanical, thermal, and electronic stability limitations. Insertion device gap-dependent systematic errors associated with the present ultraviolet photon beam position monitors similarly limit their ability to control long-term pointing stability. We report on the development of a new BPM design sensitive only to hard x-rays. Early experimental results will be presented.

  9. Development of an angled Si-PM-based detector unit for positron emission mammography (PEM) system

    Energy Technology Data Exchange (ETDEWEB)

    Nakanishi, Kouhei, E-mail: nakanishi.kouhei@c.mbox.nagoya-u.ac.jp; Yamamoto, Seiichi

    2016-11-21

    Positron emission mammography (PEM) systems have higher sensitivity than clinical whole body PET systems because they have a smaller ring diameter. However, the spatial resolution of PEM systems is not high enough to detect early stage breast cancer. To solve this problem, we developed a silicon photomultiplier (Si-PM) based detector unit for the development of a PEM system. Since a Si-PM's channel is small, Si-PM can resolve small scintillator pixels to improve the spatial resolution. Also Si-PM based detectors have inherently high timing resolution and are able to reduce the random coincidence events by reducing the time window. We used 1.5×1.9×15 mm LGSO scintillation pixels and arranged them in an 8×24 matrix to form scintillator blocks. Four scintillator blocks were optically coupled to Si-PM arrays with an angled light guide to form a detector unit. Since the light guide has angles of 5.625°, we can arrange 64 scintillator blocks in a nearly circular shape (a regular 64-sided polygon) using 16 detector units. We clearly resolved the pixels of the scintillator blocks in a 2-dimensional position histogram where the averages of the peak-to-valley ratios (P/Vs) were 3.7±0.3 and 5.7±0.8 in the transverse and axial directions, respectively. The average energy resolution was 14.2±2.1% full-width at half-maximum (FWHM). By including the temperature dependent gain control electronics, the photo-peak channel shifts were controlled within ±1.5% with the temperature from 23 °C to 28 °C. With these results, in addition to the potential high timing performance of Si-PM based detectors, our developed detector unit is promising for the development of a high-resolution PEM system.

  10. Electron-beam induced amorphization of stishovite: Silicon-coordination change observed using Si K-edge extended electron energy-loss fine structure

    International Nuclear Information System (INIS)

    Aken, P.A. van; Sharp, T.G.; Seifert, F.

    1998-01-01

    The analysis of the extended energy-loss fine structure (EXELFS) of the Si K-edge for sixfold-coordinated Si in synthetic stishovite and fourfold-coordinated Si in natural α-quartz is reported by using electron energy-loss spectroscopy (EELS) in combination with transmission electron microscopy (TEM). The stishovite Si K-edge EXELFS spectra were measured as a time-dependent series to document irradiation-induced amorphization. The amorphization was also investigated through the change in Si K- and O K-edge energy-loss near edge structure (ELNES). For α-quartz, in contrast to stishovite, electron irradiation-induced vitrification, produced no detectable changes of the EXELFS. The Si K-edge EXELFS were analysed with the classical extended X-ray absorption fine structure (EXAFS) treatment and compared to ab initio curve-waved multiple-scattering (MS) calculations of EXAFS spectra for stishovite and α-quartz. Highly accurate information on the local atomic environment of the silicon atoms during the irradiation-induced amorphization of stishovite is obtained from the EXELFS structure parameters The mean Si-O bond distance R and mean Si coordination number N changes from R=0.1775 nm and N=6 for stishovite through a disordered intermediate state (R∼0.172 nm and N∼5) to R∼0.167 nm and N∼4.5 for a nearly amorphous state similar to α-quartz (R=0.1609 nm and N=4). During the amorphization process, the Debye-Waller factor (DWF) passes through a maximum value of σ N 2 ∼83.8pm 2 as it changes from σ st 2 =51.8pm 2 for sixfold to σ qu 2 =18.4pm 2 for fourfold coordination of Si. This increase in Debye-Waller factor indicates an increase in mean-square relative displacement (MSRD) between the central silicon atom and its oxygen neighbours. Using the EXELFS data for amorphization, a new method is developed to derive the relative amounts of Si coordinations in high-pressure minerals with mixed coordination. For the radiation-induced amorphization process of

  11. Development of a Laser-based Emittance Monitor for Negative Hydrogen Beams

    CERN Document Server

    AUTHOR|(CDS)2078368; Schmauss, Bernhard; Gibson, Stephen; Boorman, Gary; Bosco, Alessio

    High energy particle accelerators are designed to collide charged particle beams and thus study the collision products. Maximising the collision rate, to generate sufficient statistics for precise measurements of rare processes, is one of the key parameters for optimising the overall collider performance. The CERN Large Hadron Collider (LHC) Injectors Upgrade (LIU) includes the construction of LINAC4, a completely new machine working as a first linear acceleration stage for the LHC beam. By accelerating a negative hydrogen beam (H-) instead of protons, it aims to double the beam brightness via a more efficient transfer to the first circular accelerator and subsequently boost the LHC collision rate. To achieve this, a precise knowledge of the transverse beam characteristics in terms of beam emittance is essential. This thesis work covers the development of a laser-based monitor meant to measure non-destructively the LINAC4 beam transverse profile and emittance. This included the implementation of dif...

  12. Development of a high-resolution electron-beam profile monitor using Fresnel zone plates

    International Nuclear Information System (INIS)

    Nakamura, Norio; Sakai, Hiroshi; Muto, Toshiya; Hayano, Hitoshi

    2004-01-01

    We present a high-resolution and real-time beam profile monitor using Fresnel zone plates (FZPs) developed in the KEK-ATF damping ring. The monitor system has an X-ray imaging optics with two FZPs. In this monitor, the synchrotron radiation from the electron beam at the bending magnet is monochromatized by a crystal monochromator and the transverse electron beam image is twenty-times magnified by the two FZPs and detected on an X-ray CCD camera. The expected spatial resolution for the selected photon energy of 3.235 keV is less than 1 μm. With the beam profile monitor, we succeeded in obtaining a clear electron-beam image and measuring the extremely small beam size less than 10 μm. It is greatly expected that the beam profile monitor will be used in high-brilliance light sources and low-emittance accelerators. (author)

  13. Current developments in CZ Si crystal growing technology; Aktuelle Entwicklungen in der Zuechtungstechnologie von CZ-Si-Kristallen

    Energy Technology Data Exchange (ETDEWEB)

    Altekrueger, Burkhard; Volk, Michael [PVA TePla AG, Wettenberg (Germany)

    2011-02-15

    The industrial growing of increasingly large and perfect silicon (Si) monocrystals for applications in microelectronics and photovoltaics requires continuous improvement of process control and growing technology. Continuous adaptation and optimization of system technology in terms of reliability, process flexibility and dimensioning are also necessary. The basic principles of industrial silicon crystal growing and the resultant requirements for the Si process and system technologies are described in the first part of this series of articles. The constantly increasing requirements for the performance and complexity of the electronic circuits (chips) in accordance with Moore's Law mean that the requirements for the perfection and dimensions of monocrystalline Si wafers and Si crystals are also continuously rising. After the introduction of the 300 mm Si wafer generation in recent years, the next Si wafer generation (450 mm) is therefore being discussed already. The technological and economic effects of these constantly increasing requirements for the necessary system technologies will be set out and discussed in the subsequent articles on the basis of current Si CZ crystal growing systems as well as new system concepts. (orig.)

  14. siRNA-loaded cationic liposomes for cancer therapy: Development, characterization and efficacy evaluation

    Science.gov (United States)

    Ying, Bo

    Cancer is a major health problem in the United States and many other parts of the world. However, cancer treatment is severely limited by the lack of highly effective cytotoxic agents and selective delivery methods which can serve as the "magic bullet" (first raised by Dr. Paul Ehrlich, the goal of targeting a specific location without causing harm to surrounding tissues or to more distant regions in the body). The revolutionary finding that tumors cannot grow beyond a microscopic size without dedicated blood supply provided a highly effective alternative for the treatment of cancer. Currently, anti-angiogenic therapy and the discovery of RNA interference makes it possible to treat some conditions by silencing disorder-causing genes of targeting cells which are otherwise difficult to eradicate with more conventional therapies. However, before siRNA technology could be widely used as a therapeutic approach, the construct must be efficiently and safely delivered to target cells. Strategies used for siRNA delivery should minimize uptake by phagocytes, enzymatic degradation by nucleases and should be taken up preferentially, if not specifically, by the intended cell population. Kinesin spindle proteins (KSP) are the motor proteins which play critical roles during mitosis. Different from tubulins which are also present in post-mitotic cells, such as axons, KSP is exclusively expressed in mitotic cells, which makes them the ideal target for anti-mitotics. In the present study, we intend to develop, characterize and evaluate a liposome-based delivery system which can deliver KSP siRNA selectively to the tumor vasculature (thus inhibiting angiogenesis, destroying tumor vasculature and eventually, eradicating tumor growth). We first developed ten different liposome preparation types with different compositions of lipids. Next, the capacity for loading siRNA and efficiency of targeting the tumor vascular supply was evaluated using relevant cellular and tumor models

  15. Beam Development/Implementation and Futher Development of the ISOLDE Laser Ion Source

    CERN Multimedia

    Kugler, E; Van duppen, P L E; Lettry, J

    2002-01-01

    % IS335 \\\\ \\\\ Already before the move to the PS-Booster (PSB) the proton-beam time-structure of 7 pulses of 2.4~$\\mu$s duration every 1.2~s was identified as the major challenge to the target and ion-source technique. It was also recognized that an intensive target development programme should be undertaken in order to exploit efficiently the properties of the Booster beam. This beam structure can have both beneficial effects and deleterious effects on the performance of the targets. On the one side the power deposition, the shock wave and the cascade of nuclear reactions may enhance the release and make the targets faster. \\\\ \\\\The selectivity with which ISOLDE can separate the products according to the chemical element is another important parameter for the experiments. Online test experiments at the SC ISOLDE-3 successfully demonstrated that resonant multi-photon excitation and final ionization by pulsed lasers is an efficient tool for the production of isobarically pure ion beams. The installation of a pe...

  16. Development of atomic-beam resonance method to measure the nuclear moments of unstable nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Sugimoto, T., E-mail: sugimoto@ribf.riken.jp [SPring-8 (Japan); Asahi, K. [Tokyo Institute of Technology, Department of Physics (Japan); Kawamura, H.; Murata, J. [Rikkyo University, Department of Physics (Japan); Nagae, D.; Shimada, K. [Tokyo Institute of Technology, Department of Physics (Japan); Ueno, H.; Yoshimi, A. [RIKEN Nishina Center (Japan)

    2008-01-15

    We have been working on the development of a new technique of atomic-beam resonance method to measure the nuclear moments of unstable nuclei. In the present study, an ion-guiding system to be used as an atomic-beam source have been developed.

  17. The Development of a Hibachi Window for Electron Beam Transmission in a KrF Laser

    International Nuclear Information System (INIS)

    Gentile, C.A.; Parsells, R.; Butler, J.E.; Sethian, J.D.; Ciebiera, L.; Hegeler, F.; Jun, C.; Langish, S.; Myers, M.

    2003-01-01

    In support of Inertial Fusion Energy (IFE), a 150 (micro)m thick silicon (Si) wafer coated on one side with a 1.2 (micro)m nanocrystalline diamond foil is being fabricated as an electron beam transmission (hibachi) window for use in KrF lasers. The hibachi window separates the lasing medium from the electron beam source while allowing the electron beam to pass through. The hibachi window must be capable of withstanding the challenging environment presented in the lasing chamber, which include: fluorine gas, delta pressure >2 atm at 5 Hz, and a high heat flux due to the transmission of electrons passing through the foil. Tests at NRL/Electra and at PPPL have shown that a device employing these novel components in the stated configuration provide for a robust hibachi window with structural integrity

  18. Development of an efficient grain refiner for Al-7Si alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kori, S.A.; Murty, B.S.; Chakraborty, M. [Indian Inst. of Technol., Kharagpur (India). Dept. of Metall. and Mater. Eng.

    2000-03-15

    The response of Al-7Si alloy towards grain refinement by Al-Ti-B master alloys (with different Ti-B ratios) at different addition levels has been studied in detail. The results indicate that high B-containing master alloys are powerful grain refiners when compared to conventional grain refiners like Al-5Ti-lB master alloys. In the present study, indigenously developed master alloys have been used for the grain refinement of alloys Al-7Si and LM-25. Significant improvements in mechanical properties have been obtained with a combination of grain refiner and Sr as modifier. (orig.)

  19. Development and Testing of Atomic Beam-Based Plasma Edge Diagnostics in the CIEMAT Fusion Devices

    International Nuclear Information System (INIS)

    Tafalla, D.; Tabares, F.L.; Ortiz, P.; Herrero, V.J.; Tanarro, I.

    1998-01-01

    In this report the development of plasma edge diagnostic based on atomic beam techniques fir their application in the CIEMAT fusion devices is described. The characterisation of the beams in laboratory experiments at the CSIC, together with first results in the Torsatron TJ-II are reported. Two types of beam diagnostics have been developed: a thermal (effusive) Li and a supersonic, pulsed He beams. This work has been carried out in collaboration between the institutions mentioned above under partial financial support by EURATOM. (Author) 17 refs

  20. Status of U3Si2-Al fuel development in China

    International Nuclear Information System (INIS)

    Sun Rongxian; Huang Dechen; Yin Changgeng; Zhang Qindi; He Fengqi; Li Shuhua; Xiang Xingbi; Zhang Zhiyi; Wang Zhaoyue

    1995-01-01

    On the basis of the research and development work, a production line of U 3 Si 2 -Al dispersion fuel elements has been established and tens of the fuel elements have been produced. A lot of technical improvements and reliable inspection system ensure that all technical performance of the fuel elements meet International standards. (author)

  1. Topography development on selected inert gas and self-ion bombarded Si

    International Nuclear Information System (INIS)

    Vishnyakov, V.; Carter, G.; Goddard, D.T.; Nobes, M.J.

    1995-01-01

    An AFM and SEM study of the topography induced by 20 keV Si + , Ar + and Xe + ion bombardment of Si at 45 o incidence angles and for ion fluences between 10 17 and 10 20 cm -2 has been undertaken at room temperature. All species generate an atomic scale random roughness, the magnitude of which does not increase extensively with ion fluence, suggesting the operation of a local relaxation process. This nanometre scale roughness forms, for Ar and Xe, a background for coarser micrometre scale structures such as pits, chevrons and waves. Apart from isolated etch pits Si + irradiation generates no repetitive micrometre scale structures. Xe + irradiation produces well developed transverse waves while Ar + irradiation results in isolated chevron-like etch pit trains and ripple patches. This latter pattern evolves, with increasing ion fluence, to a corrugated facet structure. The reasons for the different behaviours are still not fully clarified. (author)

  2. Progress in the development of uranium silicide (U3Si2) fuel at BATAN

    International Nuclear Information System (INIS)

    Suripto, A.; Soentono, S.

    1995-01-01

    After successful fabrication of two full-size prototype fuel elements containing ∼3.0 gU/cm 3 in the form of U 3 Si 2 -Al dispersion now undergoing irradiation in the Reaktor Serba Guna G.A. Siwabessy (RSG-GAS) core since 1990, further development in U 3 Si 2 -A2 dispersion fuel element manufacturing has been pursued, whose progress in discussed in this paper, with a special attention on the use of much higher-loading aimed at obtaining a better understanding on the influence of higher-loading on fuel core and plate manufacturing and quality. At present, high-loading U 3 Si 2 -AI dispersion miniplates are being manufactured for preparing some mini-fuel elements to be test-irradiated in the new MTR in-pile loop of the RSG-GAS. (author)

  3. Development of an energy selector system for laser-driven proton beam applications

    Energy Technology Data Exchange (ETDEWEB)

    Scuderi, V., E-mail: scuderiv@lns.infn.it [Department of Experimental Program at ELI-Beamlines, Institute of Physics of the ASCR, ELI-Beamlines project, Na Slovance 2, Prague (Czech Republic); Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Bijan Jia, S. [Ferdowsi University of Mashhad, Azadi Square, Mashhad (Iran, Islamic Republic of); Carpinelli, M. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Cirrone, G.A.P. [Department of Experimental Program at ELI-Beamlines, Institute of Physics of the ASCR, ELI-Beamlines project, Na Slovance 2, Prague (Czech Republic); Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Cuttone, G. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Korn, G. [Department of Experimental Program at ELI-Beamlines, Institute of Physics of the ASCR, ELI-Beamlines project, Na Slovance 2, Prague (Czech Republic); Licciardello, T. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Maggiore, M. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, Viale dell' Universit 2, Legnaro (Pd) (Italy); Margarone, D. [Department of Experimental Program at ELI-Beamlines, Institute of Physics of the ASCR, ELI-Beamlines project, Na Slovance 2, Prague (Czech Republic); Pisciotta, P.; Romano, F. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Schillaci, F. [Department of Experimental Program at ELI-Beamlines, Institute of Physics of the ASCR, ELI-Beamlines project, Na Slovance 2, Prague (Czech Republic); Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Stancampiano, C. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); and others

    2014-03-11

    Nowadays, laser-driven proton beams generated by the interaction of high power lasers with solid targets represent a fascinating attraction in the field of the new acceleration techniques. These beams can be potentially accelerated up to hundreds of MeV and, therefore, they can represent a promising opportunity for medical applications. Laser-accelerated proton beams typically show high flux (up to 10{sup 11} particles per bunch), very short temporal profile (ps), broad energy spectra and poor reproducibility. In order to overcome these limitations, these beams have be controlled and transported by means of a proper beam handling system. Furthermore, suitable dosimetric diagnostic systems must be developed and tested. In the framework of the ELIMED project, we started to design a dedicated beam transport line and we have developed a first prototype of a beam line key-element: an Energy Selector System (ESS). It is based on permanent dipoles, capable to control and select in energy laser-accelerated proton beams. Monte Carlo simulations and some preliminary experimental tests have been already performed to characterize the device. A calibration of the ESS system with a conventional proton beam will be performed in September at the LNS in Catania. Moreover, an experimental campaign with laser-driven proton beam at the Centre for Plasma Physics, Queens University in Belfast is already scheduled and will be completed within 2014.

  4. Development of plant mutation techniques using ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Si Yong; Park, In Sook; Song, Hi Sup; Kim, Dong Sub; Kim, Soo Yeon

    2006-06-15

    It has been reported that ion beam with high liner energy transfer (LET) show relative high biological effectiveness (RBE) and more effective for induced plant mutation than low LET radiation i.e., X-rays, gamma rays and electrons. This study was conducted to induce mutation of in vitro cultured orchid and Chrysanthemum using proton beam of the MC-50 cyclotron (50 MeV) at the Korea Institute of Radiological and Medical Science. In vitro cultured stems of chrysanthemum(cv. Migok) and protocom-like bodies(PLBs) of Dendrobium orchid (cv. Kingianum) placed in the plastic petridish (5.5cm in diameter) with agar medium were irradiated by the proton beam with various dose ranges of 10, 25, 50, 100 Gy under the condition of 5nA beam current. Those irradiated plants were transferred to subculture media and then investigated growth characteristics. Shoot growth of chrysanthemum and orchid was decreased by increase of irradiation dose. In particular, new shoot formation was hardly founded over 50Gy in chrysanthemum and 100 Gy in orchid. Some leaf mutants were observed at the 25 Gy and 50 Gy irradiated PLBs of the orchid. The dry seeds of hot pepper, rapeseed, rice and perilla also were irradiated with proton beam of MC-50 cyclotron and then measured germination rate and early growth of M1 plants compared with gamma ray irradiation.

  5. Development of plant mutation techniques using ion beam

    International Nuclear Information System (INIS)

    Kang, Si Yong; Park, In Sook; Song, Hi Sup; Kim, Dong Sub; Kim, Soo Yeon

    2006-06-01

    It has been reported that ion beam with high liner energy transfer (LET) show relative high biological effectiveness (RBE) and more effective for induced plant mutation than low LET radiation i.e., X-rays, gamma rays and electrons. This study was conducted to induce mutation of in vitro cultured orchid and Chrysanthemum using proton beam of the MC-50 cyclotron (50 MeV) at the Korea Institute of Radiological and Medical Science. In vitro cultured stems of chrysanthemum(cv. Migok) and protocom-like bodies(PLBs) of Dendrobium orchid (cv. Kingianum) placed in the plastic petridish (5.5cm in diameter) with agar medium were irradiated by the proton beam with various dose ranges of 10, 25, 50, 100 Gy under the condition of 5nA beam current. Those irradiated plants were transferred to subculture media and then investigated growth characteristics. Shoot growth of chrysanthemum and orchid was decreased by increase of irradiation dose. In particular, new shoot formation was hardly founded over 50Gy in chrysanthemum and 100 Gy in orchid. Some leaf mutants were observed at the 25 Gy and 50 Gy irradiated PLBs of the orchid. The dry seeds of hot pepper, rapeseed, rice and perilla also were irradiated with proton beam of MC-50 cyclotron and then measured germination rate and early growth of M1 plants compared with gamma ray irradiation

  6. Si Nanopores Development for External Control of Transport of Biomolecules

    Energy Technology Data Exchange (ETDEWEB)

    Ileri, N; Tringe, J; Letant, S; Palozoglu, A; Stroeve, P; Faller, R

    2008-06-13

    Nazar Ileri has been involved in an independent, multidisciplinary effort to create a new class of molecular sieves for proteins and viruses. Her experimental work has been performed concurrently at two campuses, LLNL and UC Davis, while theoretical components have been largely accomplished at UC Davis. As will be described, the devices she is creating have great potential to improve very significantly the efficiency and selectivity of molecular transport over what is presently available from state-of-the-art membranes. Our biotechnology training program is based on an integrated study of the transport of biomolecules through conically-shaped, nanoporous silicon membranes. The overall objective of this effort is to demonstrate an efficient, highly selective membrane technology that is manufacturable for macroscopic areas and can be employed in sensing, diagnostic and biomedical applications. Our specific aims are to (1) fabricate and characterize the physical characteristics of the membranes, (2) to demonstrate their utility for molecular transport and separation, and (3) to develop models that will facilitate understanding of these devices as well as improved performance of the next generation of devices. We have proposed that the conical pores have superior performance characteristics compared to other porous filters. To study this hypothesis, complementary approaches from different disciplines, such as membrane synthesis, experiment, and molecular simulation need to be combined. This provides an ideal training environment for a future leader in biotechnology. Hence, for this study, Nazar Ileri has started to carry out a full range of experimental and theoretical investigations under our guidance. First, she has begun fabrication of filters with conical/pyramidal pores. She characterized the pores by AFM and SEM, and analyzed the images using wavelets and other mathematical tools. She has also started to conduct biomolecule transport experiments to compare the

  7. Si Nanopores Development for External Control of Transport of Biomolecules

    International Nuclear Information System (INIS)

    Ileri, N.; Tringe, J.; Letant, S.; Palozoglu, A.; Stroeve, P.; Faller, R.

    2008-01-01

    Nazar Ileri has been involved in an independent, multidisciplinary effort to create a new class of molecular sieves for proteins and viruses. Her experimental work has been performed concurrently at two campuses, LLNL and UC Davis, while theoretical components have been largely accomplished at UC Davis. As will be described, the devices she is creating have great potential to improve very significantly the efficiency and selectivity of molecular transport over what is presently available from state-of-the-art membranes. Our biotechnology training program is based on an integrated study of the transport of biomolecules through conically-shaped, nanoporous silicon membranes. The overall objective of this effort is to demonstrate an efficient, highly selective membrane technology that is manufacturable for macroscopic areas and can be employed in sensing, diagnostic and biomedical applications. Our specific aims are to (1) fabricate and characterize the physical characteristics of the membranes, (2) to demonstrate their utility for molecular transport and separation, and (3) to develop models that will facilitate understanding of these devices as well as improved performance of the next generation of devices. We have proposed that the conical pores have superior performance characteristics compared to other porous filters. To study this hypothesis, complementary approaches from different disciplines, such as membrane synthesis, experiment, and molecular simulation need to be combined. This provides an ideal training environment for a future leader in biotechnology. Hence, for this study, Nazar Ileri has started to carry out a full range of experimental and theoretical investigations under our guidance. First, she has begun fabrication of filters with conical/pyramidal pores. She characterized the pores by AFM and SEM, and analyzed the images using wavelets and other mathematical tools. She has also started to conduct biomolecule transport experiments to compare the

  8. Influencing factors on the size uniformity of self-assembled SiGe quantum rings grown by molecular beam epitaxy.

    Science.gov (United States)

    Cui, J; Lv, Y; Yang, X J; Fan, Y L; Zhong, Z; Jiang, Z M

    2011-03-25

    The size uniformity of self-assembled SiGe quantum rings, which are formed by capping SiGe quantum dots with a thin Si layer, is found to be greatly influenced by the growth temperature and the areal density of SiGe quantum dots. Higher growth temperature benefits the size uniformity of quantum dots, but results in low Ge concentration as well as asymmetric Ge distribution in the dots, which induces the subsequently formed quantum rings to be asymmetric in shape or even broken somewhere in the ridge of rings. Low growth temperature degrades the size uniformity of quantum dots, and thus that of quantum rings. A high areal density results in the expansion and coalescence of neighboring quantum dots to form a chain, rather than quantum rings. Uniform quantum rings with a size dispersion of 4.6% and an areal density of 7.8×10(8) cm(-2) are obtained at the optimized growth temperature of 640°C.

  9. Advanced development of particle beam probe diagnostic systems

    International Nuclear Information System (INIS)

    Hickok, R.L.; Crowley, T.P.; Connor, K.A.

    1990-11-01

    This progress report covers the period starting with the approval to go ahead with the 2 MeV heavy ion beam probe (HIBP) for TEXT Upgrade to the submission of the grant renewal proposal. During this period the co-principal investigators, R. L. Hickok and T. P. Crowley have each devoted 45% of their time to this Grant. Their effort has been almost exclusively devoted to the design and fabrication of the 2 MeV HIBP system. The 1989 report that described the advantages of a 2 MeV HIBP for TEXT Upgrade compared to the existing 0.5 MeV HIBP and outlined the design of the 2 MeV system is attached as Appendix A. Since the major effort under the renewal proposal will be the continued fabrication, installation and operation of the 2 MeV system on TEXT Upgrade, we describe some of the unique results that have been obtained with the 0.5 MeV system on TEXT. For completeness, we also include the preliminary operation of the 160 keV HIBP on ATF. We present the present fabrication status of the 2 MeV system with the exception of the electrostatic energy analyzer. The energy analyzer which is designed to operate with 400 kV on the top plate is a major development effort and is treated separately. Included in this section are the results obtained with a prototype no guard ring analyzer, the conceptual design for the 2 MeV analyzer, the status of the high voltage testing of full size analyzer systems and backup plans if it turns out that it is impossible to hold 400 kV on an analyzer this size

  10. New High-Performance SiC Fiber Developed for Ceramic Composites

    Science.gov (United States)

    DiCarlo, James A.; Yun, Hee Mann

    2002-01-01

    Sylramic-iBN fiber is a new type of small-diameter (10-mm) SiC fiber that was developed at the NASA Glenn Research Center and was recently given an R&D 100 Award for 2001. It is produced by subjecting commercially available Sylramic (Dow Corning, Midland, MI) SiC fibers, fabrics, or preforms to a specially designed high-temperature treatment in a controlled nitrogen environment for a specific time. It can be used in a variety of applications, but it currently has the greatest advantage as a reinforcement for SiC/SiC ceramic composites that are targeted for long-term structural applications at temperatures higher than the capability of metallic superalloys. The commercial Sylramic SiC fiber, which is the precursor for the Sylramic-iBN fiber, is produced by Dow Corning, Midland, Michigan. It is derived from polymers at low temperatures and then pyrolyzed and sintered at high temperatures using boron-containing sintering aids (ref. 1). The sintering process results in very strong fibers (>3 GPa) that are dense, oxygen-free, and nearly stoichiometric. They also display an optimum grain size that is beneficial for high tensile strength, good creep resistance, and good thermal conductivity (ref. 2). The NASA-developed treatment allows the excess boron in the bulk to diffuse to the fiber surface where it reacts with nitrogen to form an in situ boron nitride (BN) coating on the fiber surface (thus the product name of Sylramic-iBN fiber). The removal of boron from the fiber bulk allows the retention of high tensile strength while significantly improving creep resistance and electrical conductivity, and probably thermal conductivity since the grains are slightly larger and the grain boundaries cleaner (ref. 2). Also, as shown in the graph, these improvements allow the fiber to display the best rupture strength at high temperatures in air for any available SiC fiber. In addition, for CMC applications under oxidizing conditions, the formation of an in situ BN surface layer

  11. Facilities for radiotherapy with ion beams status and worldwide developments

    CERN Document Server

    Wolf, B H

    1999-01-01

    Forty-five years after the first ion beam therapy in Berkeley around 25,000 cancer patients worldwide have been treated successfully. Ion accelerators, designed for nuclear research, delivered most of this treatment. The first hospital-based facility started operation in 1998 at Loma Linda California, the first for heavier ions at Chiba, Japan in 1994 and the first commercially delivered facilities started operation in 1998 at Kashiwa, Japan. In 2000, the Harvard Medical Centre, Boston, US, will commence operation and several new facilities are planned or under construction worldwide, although none in Australia. This paper will discuss the physical and biological advantages of ion beams over x-rays and electrons. In the treatment of cancer patients ion beam therapy is especially suited for localised tumours in radiation sensitive areas like skull or spine. Heavier ions are also effective in anoxic tumour cells (found around the normally oxygenated cell population). An additional advantage of the heavier carbo...

  12. The effect of neodymium on the microcracks generated on the Al–17.5Si alloy surface treated by high current pulsed electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Liang; Gao, Bo, E-mail: gaob@smm.neu.edu.cn; Zhu, Guanglin; Hao, Yi; Sun, Shuchen; Tu, Ganfeng

    2016-02-28

    Graphical abstract: SEM results demonstrate that microcracks are remarkably removed from the Al–17.5Si alloy surface after HCPEB treatment due to Nd element, and they decrease in length at high pulse number, showing a decrease in the stress concentration in the primary Si phase during the cooling process of HCPEB, as shown in Fig. 1. Therefore, the microcrack elimination is attributed to reducing the stress concentration. - Highlights: • The main highlights in this paper are summarized as follows: (1) After adding rare earth Nd, the microcracks are remarkably removed from an Al–17.5Si alloy surface by HCPEB, resulting in an improved corrosion resistance of the alloy surface. (2) A site-fixed observation of SEM is first proposed in HCPEB-treated technology, and a microcrack evolution with increasing pulsed numbers is observed for alloy surfaces using this method. (3) The elimination mechanism of microcracks with rare earth Nd is first presented in the present work. (4) Compound modification of rare earth Nd and HCPEB technology on the Al–17.5Si alloy is first investigated. - Abstract: In the present work, the effect of Nd on the microcracks generated on an Al–17.5Si alloy surface by a high current pulsed electron beam (HCPEB) was investigated. By a newly proposed site-fixed observation, the propagation of microcracks with increasing pulsed numbers first increases and then decreases due to the Nd element. The crack density decreases from 0.0669 mm/mm{sup 2} of 5 pulses to 0.00687 mm/mm{sup 2} of 50 pulses. EPMA analysis results indicate that Nd is uniformly distributed on the HCPEB-treated alloy surface. Nano-silicon particles and nano-Al cellular structures were formed by TEM observation, showing grain refinement of the alloy surface. The microcrack elimination is attributed to a decrease in the stress concentration in the primary Si phase during the cooling process of HCPEB. The electrochemical measurement shows that the corrosion current density

  13. Development of vacuum components for neutral beam injection applications

    International Nuclear Information System (INIS)

    Schwenterly, S.W.

    1977-01-01

    Neutral beam injectors and divertors for fusion devices require very high-speed pumping capabilities to remove cold gas and impurities from the beam and plasma drift regions. Cryopumping is one of the most favorable methods due to its freedom from contamination and relatively low capital cost. The theory of cryosorption pumping is summarized and contrasted with the process of cryocondensation. A variable-temperature cryostat for basic studies on small test cryosorption panels is described. Using results of these studies, a large sorption panel with an inlet area of 2 m 2 is being designed and fabricated. The design characteristics of this pump are discussed

  14. Development of an Efficient Steel Beam Section for Modular Construction Based on Six-Sigma

    Directory of Open Access Journals (Sweden)

    Tae-Hyu Ha

    2016-01-01

    Full Text Available This study presents a systematic approach for the development of an efficient steel beam section for modular construction based on Six-Sigma. Although the Six-Sigma is frequently implemented in manufacturing and other service industries, it is a relatively new concept in the area of building design and construction. As a first step in this approach, market studies and surveys are conducted to obtain the opinions of potential customers. Then the opinions of customers are converted into quality characteristics for the steel beam using the quality function deployment methodology. A steel hollow flanged channel is chosen as the main modular beam shape, and the design concept is derived and developed by applying the Pugh matrix methodology. A pilot test was performed to validate the effectiveness of the developed beam section. The results indicated that the developed channel beam section showed excellent performance and retained high accuracy in fabrication, thus resulting in a significant reduction of steel consumption.

  15. Development of a new RFQ beam cooler and buncher for the CANREB project at TRIUMF

    Energy Technology Data Exchange (ETDEWEB)

    Barquest, B.R. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3 (Canada); Bale, J.C.; Dilling, J. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3 (Canada); UBC Department of Physics and Astronomy, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Gwinner, G. [University of Manitoba, Department of Physics and Astronomy, Allen Building, Winnipeg, MB R3T 2N2 (Canada); Kanungo, R. [Saint Mary’s University, Astronomy and Physics Department, 923 Robie Street, Halifax, NS B3H 3C3 (Canada); Krücken, R. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3 (Canada); UBC Department of Physics and Astronomy, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Pearson, M.R. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3 (Canada)

    2016-06-01

    A new radiofrequency quadrupole (RFQ) based ion beam cooler and buncher is under development for the CANadian Rare-isotope facility with Electron Beam ion source (CANREB) project at TRIUMF. The CANREB project requires an RFQ buncher that will efficiently accept continuous beams of rare isotopes from either the Advanced Rare IsotopE Laboratory (ARIEL) or Isotope Separator and ACcelerator (ISAC) target by way of a high resolution magnetic spectrometer, with energies up to 60 keV and deliver bunched beams to an electron beam ion source (EBIS) for charge breeding. The energy of the bunched beam delivered to the EBIS will be adjustable to match the requirements of the existing post acceleration infrastructure. The CANREB RFQ incorporates design considerations to facilitate ease of use over a wide range of ion masses, and is intended to accommodate incident beam rates as high as 10{sup 8} pps, delivering beam bunches at 100 Hz. An overview of the CANREB RFQ design concept will be presented, informed by results from both ion optical simulations as well as commissioning efforts with other beam cooler and buncher devices. Simulation results indicate that the design is well suited to deliver high quality bunched beams with high efficiency with as many as 10{sup 6} ions per bunch.

  16. Metallic beam developments for the SPIRAL 2 project

    Energy Technology Data Exchange (ETDEWEB)

    Barué, C., E-mail: barue@ganil.fr; Canet, C.; Dupuis, M.; Flambard, J. L.; Frigot, R.; Jardin, P.; Lemagnen, F.; Maunoury, L.; Osmond, B. [GANIL, CEA/CNRS, Bd Henri Becquerel, BP 55027, 14076 Caen Cedex 5 (France); Lamy, T.; Sole, P.; Thuillier, T. [LPSC, Université Joseph Fourier Grenoble 1, Grenoble INP, 53 rue des Martyrs, 38026 Grenoble Cedex (France); Peaucelle, C. [IPNL, Université de Lyon, Université de Lyon 1,CNRS/IN2P3 CERN, 4 rue E. Fermi, 69622 Villeurbanne Cedex (France)

    2014-02-15

    The SPIRAL 2 facility, currently under construction, will provide either stable or radioactive beams at high intensity. In addition to the high intensity of stable beams, high charge states must be produced by the ion source to fulfill the RFQ LINAC injection requirements: Q/A = 1/3 at 60 kV ion source extraction voltage. Excepting deuterons and hydrogen, most of the stable beam requests concern metallic elements. The existing 18 GHz electron cyclotron resonance ion source (ECRIS) Phoenix V2 designed at LPSC Grenoble has been used for the tests and will be the source for the SPIRAL 2 commissioning. The tests performed at LPSC for calcium ({sup 40}Ca{sup 14+} and {sup 40}Ca{sup 16+}), nickel ({sup 58}Ni{sup 19+}), and sulfur ({sup 32}S{sup 11+}) are described and discussed. Due to the very high charge states required, the oven method has been chosen. An intensity of 1 pμA has been reached for those elements. The performance and the beam stability have been studied using different buffer gases, and some ionization efficiency preliminary results are given.

  17. Recent developments in high charge state heavy ion beams at the LBL 88-inch Cyclotron

    International Nuclear Information System (INIS)

    Gough, R.A.; Clark, D.J.; Glasgow, L.R.

    1978-01-01

    Recent advances in design and operation of the internal PIG sources at the LBL 88-Inch Cyclotron have led to the development of high charge state (0.4 16 O 8+ . Total external intensities of these beams range from 10 12 particles/s for 6 Li 3+ to 0.1 particles/s for 16 O 8+ . Techniques have been developed for routine tune-out of the low intensity beams. These include use of model beams and reliance on the large systematic data base of cyclotron parameters which has been developed over many years of operation. Techniques for delivery of these weak beams to the experimental target areas are presented. Source design and operation, including special problems associated with Li, Be, and B beams are discussed

  18. Development of over-production strain of saccharification enzyme and biomass pretreatment by proton beam irradiation

    International Nuclear Information System (INIS)

    Kim, S. O.; Lee, J. Y.; Song, Y. S.; Shin, H. S.

    2009-04-01

    - The first year : Pre-treatment of biomass by proton beam irradiation and characterization of the pretreated biomass by IR and SEM - The second year : Strain development by proton beam irradiation for the production of cellulase and hemicellulase - The third year : Optimization of Saccharification process by cellulase and hemicellulase

  19. Development of x-y table for baby electron beam detection using dispose printer

    International Nuclear Information System (INIS)

    Leo Kwee Wah; Mohd Rizal Md Chulan; Muhamad Zahidee Taat; Abu Bakar Md Ghazali; Mohamad Nor Atan; Siti A'iasah Hashim

    2005-01-01

    This paper describes the development of X-Y table using the dispose printer. It consists the mechanical part and the control (Interfacing and software/programming) part description. As the result, the x-y table will be used to moves the electron beam detector for the baby electron beam machine. (Author)

  20. In-beam γ-ray Spectroscopy of {sup 30}P via the {sup 28}Si({sup 3}He,pγ){sup 30}P Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Mcneice, E.; Setoodehnia, K. [Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1 (Canada); Singh, B., E-mail: ndgroup@mcmaster.ca [Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1 (Canada); Abe, Y. [Institute of Physics, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8577 (Japan); Binh, D.N. [Center for Nuclear Study (CNS), the University of Tokyo, Wako Branch at RIKEN, Wako, Saitama 351-0198 (Japan); Chen, A.A.; Chen, J. [Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1 (Canada); Cherubini, S. [INFN-Laboratori Nazionali del Sud and Dipartimento di Fisica ed Astronomia, Università di Catania, 95123 Catania (Italy); Center for Nuclear Study (CNS), the University of Tokyo, Wako Branch at RIKEN, Wako, Saitama 351-0198 (Japan); Fukuoka, S. [Institute of Physics, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8577 (Japan); Hashimoto, T. [Center for Nuclear Study (CNS), the University of Tokyo, Wako Branch at RIKEN, Wako, Saitama 351-0198 (Japan); Hayakawa, T. [Japan Atomic Energy Agency (JAEA), Tokai–mura, Ibaraki 319-1195 (Japan); Ishibashi, Y.; Ito, Y. [Institute of Physics, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8577 (Japan); Kahl, D. [Center for Nuclear Study (CNS), the University of Tokyo, Wako Branch at RIKEN, Wako, Saitama 351-0198 (Japan); Komatsubara, T. [Institute of Physics, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8577 (Japan); Kubono, S. [Nishina Center, the Institute of Physical and Chemical Research (RIKEN), Wako, Saitama 351-0198 (Japan); Moriguchi, T.; Nagae, D.; Nishikiori, R.; Niwa, T. [Institute of Physics, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8577 (Japan); and others

    2014-06-15

    The level structure of {sup 30}P up to 8.25 MeV was investigated via in-beam γ-ray spectroscopy using the {sup 28}Si({sup 3}He,pγ){sup 30}P reaction at 9 MeV at the University of Tsukuba Tandem Accelerator Complex in Japan. An energy level scheme was deduced from γ-γ coincidence measurements. 47 new transitions have been observed from the previously known states (mostly resonances), thereby reducing the uncertainties in the excitation energies of 17 states from 3 to 10 keV to values of < 1 keV. Furthermore, spin assignments based on measurements of γ-ray angular distributions and γ-γ directional correlation of oriented nuclei (DCO ratios) were made for several observed levels of {sup 30}P.

  1. Ion-beam-induced ferromagnetism in Mn-doped PrFeO{sub 3} thin films grown on Si (100)

    Energy Technology Data Exchange (ETDEWEB)

    Sultan, Khalid; Ikram, M.; Mir, Sajad Ahmad; Habib, Zubida; Aarif ul Islam, Shah [National Institute of Technology, Solid State Physics Lab. Department of Physics, Srinagar, J and K (India); Ali, Yasir [Saint Longwal Institute of Engineering and Technology, Sangrur, Punjab (India); Asokan, K. [Inter University Accelerator Centre, Materials Science Division, New Delhi (India)

    2016-01-15

    The present study shows that the ion beam irradiation induces room-temperature ferromagnetic ordering in pulsed laser-deposited Mn-doped PrFeO{sub 3} thin films on Si (100) apart from change in the morphological, structural and electrical properties. Dense electronic excitation produced by high-energy 120 MeV Ag{sup 9+} ion irradiation causes change in surface roughness, crystallinity and strain. It is also evident that these excitations induce the magnetic ordering in this system. The observed modifications are due to the large electronic energy deposited by swift heavy ions irradiation. The appearance of ferromagnetism at 300 K in these samples after irradiation may be attributed to the canting of the antiferromagnetically ordered spins due to the structural distortion. (orig.)

  2. Real-time observation of rotational twin formation during molecular-beam epitaxial growth of GaAs on Si (111) by x-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Hidetoshi, E-mail: hsuzuki@cc.miyazaki-u.ac.jp [Faculty of Engineering, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192 (Japan); Nakata, Yuka; Takahasi, Masamitu [Graduate School of Materials Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Hyogo 678-1297 (Japan); Quantum Beam Science Center, Japan Atomic Energy Agency, 1-1-1 Koto, Sayo-cho, Hyogo 679-5148 (Japan); Ikeda, Kazuma [Toyota Technological Institute, 2-12-1 Hisakata, Tempaku, Nagoya 468-8511 (Japan); Ohshita, Yoshio; Morohara, Osamu; Geka, Hirotaka; Moriyasu, Yoshitaka [Advanced Devices and Sensor Systems Development Center, Asahi Kasei Co. Ltd., 2-1 Samejima, Fuji 416-8501 (Japan)

    2016-03-15

    The formation and evolution of rotational twin (TW) domains introduced by a stacking fault during molecular-beam epitaxial growth of GaAs on Si (111) substrates were studied by in situ x-ray diffraction. To modify the volume ratio of TW to total GaAs domains, GaAs was deposited under high and low group V/group III (V/III) flux ratios. For low V/III, there was less nucleation of TW than normal growth (NG) domains, although the NG and TW growth rates were similar. For high V/III, the NG and TW growth rates varied until a few GaAs monolayers were deposited; the mean TW domain size was smaller for all film thicknesses.

  3. Formation of oxygen-related defects enhanced by fluorine in BF{sub 2}{sup +}-implanted Si studied by a monoenergetic positron beam

    Energy Technology Data Exchange (ETDEWEB)

    Uedono, Akira; Moriya, Tsuyoshi; Tanigawa, Shoichiro [Tsukuba Univ., Ibaraki (Japan). Inst. of Materials Science; Kawano, Takao; Nagai, Ryo; Umeda, Kazunori

    1995-12-01

    Defects in 25-keV BF{sub 2}{sup +}- or As{sup +}-implanted Si specimens were probed by a monoenergetic positron beam. For the As{sup +}-implanted specimen, the depth profile of defects was obtained from measurements of Doppler broadening profiles as a function of incident positron energy. The major species of the defects was identified as divacancies. For ion-implanted specimens after annealing treatment, oxygen-related defects were found to be formed. For the BF{sub 2}{sup +}-implanted specimen before annealing treatment, such defects were formed in the subsurface region, where oxygen atoms were implanted by recoil from oxide films. This was attributed to enhanced formation of oxygen-related defects by the presence of F atoms. (author)

  4. Structural, optical, and hydrogenation properties of ZnO nanowall networks grown on a Si (1 1 1) substrate by plasma-assisted molecular beam epitaxy

    International Nuclear Information System (INIS)

    Su, S.C.; Lu, Y.M.; Zhang, Z.Z.; Li, B.H.; Shen, D.Z.; Yao, B.; Zhang, J.Y.; Zhao, D.X.; Fan, X.W.

    2008-01-01

    ZnO nanowall networks were grown on a Si (1 1 1) substrate by plasma-assisted molecular beam epitaxy (P-MBE) without using catalysts. Scanning electronic microscopy (FE-SEM) confirmed the formation of nanowalls with a thickness of about 10-20 nm. X-ray diffraction (XRD) showed that the ZnO nanowall networks were crystallized in a wurtzite structure with their height parallel to the direction. Photoluminescence (PL) of the ZnO nanowall networks exhibited free excitons (FEs), donor-bound exciton (D 0 X), donor-acceptor pair (DAP), and free exciton to acceptor (FA) emissions. The growth mechanism of the ZnO nanowall networks was discussed, and their hydrogenation was also studied

  5. Pulsed EPR study of low-dose irradiation effects in L-alanine crystals irradiated with γ-rays, Ne and Si ion beams

    International Nuclear Information System (INIS)

    Rakvin, B.; Maltar-Strmecki, N.; Nakagawa, K.

    2007-01-01

    Low-dose irradiation effects in L-alanine single crystals irradiated with γ-rays, Ne and Si ion beams have been investigated by means of a two-pulse electron spin echo (ESE) technique. An effective phase memory time, T M , was measured from the first stable L-alanine radical, SAR1, and its complex relaxation mechanism is discussed. Both spectral and instantaneous diffusion contributions to the total effective relaxation rate have been extrapolated through the detection of the two-pulse ESE signal as a function of turning angle. The local microscopic concentration of paramagnetic centers C(ions)/C(γ-ray) for low-dose heavy-ion irradiation has been deduced from the corresponding spin-spin interaction

  6. SiGe Integrated Circuit Developments for SQUID/TES Readout

    Science.gov (United States)

    Prêle, D.; Voisin, F.; Beillimaz, C.; Chen, S.; Piat, M.; Goldwurm, A.; Laurent, P.

    2018-03-01

    SiGe integrated circuits dedicated to the readout of superconducting bolometer arrays for astrophysics have been developed since more than 10 years at APC. Whether for Cosmic Microwave Background (CMB) observations with the QUBIC ground-based experiment (Aumont et al. in astro-ph.IM, 2016. arXiv:1609.04372) or for the Hot and Energetic Universe science theme with the X-IFU instrument on-board of the ATHENA space mission (Barret et al. in SPIE 9905, space telescopes & instrumentation 2016: UV to γ Ray, 2016. https://doi.org/10.1117/12.2232432), several kinds of Transition Edge Sensor (TES) (Irwin and Hilton, in ENSS (ed) Cryogenic particle detection, Springer, Berlin, 2005) arrays have been investigated. To readout such superconducting detector arrays, we use time or frequency domain multiplexers (TDM, FDM) (Prêle in JINST 10:C08015, 2016. https://doi.org/10.1088/1748-0221/10/08/C08015) with Superconducting QUantum Interference Devices (SQUID). In addition to the SQUID devices, low-noise biasing and amplification are needed. These last functions can be obtained by using BiCMOS SiGe technology in an Application Specific Integrated Circuit (ASIC). ASIC technology allows integration of highly optimised circuits specifically designed for a unique application. Moreover, we could reach very low-noise and wide band amplification using SiGe bipolar transistor either at room or cryogenic temperatures (Cressler in J Phys IV 04(C6):C6-101, 1994. https://doi.org/10.1051/jp4:1994616). This paper discusses the use of SiGe integrated circuits for SQUID/TES readout and gives an update of the last developments dedicated to the QUBIC telescope and to the X-IFU instrument. Both ASIC called SQmux128 and AwaXe are described showing the interest of such SiGe technology for SQUID multiplexer controls.

  7. Development of Beam Diagnostic Tools for Monitoring Cyclotron Beams at Production Intensities

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Mikael [Hevesy Laboratory, Risoe-DTU National Laboratory, DK-4000 Roskilde (Denmark)

    2009-07-01

    This final report for the IAEA-CRP on “Improved High Current Liquid and Gas Targets for Cyclotron Produced Radioisotopes” reports the progress made as part of the Danish participation in the above CRP. Some of the work is the result of international, multi-institutional collaboration and/or research student education, and credit is hereby given to my former students Helge Thisgaard and Jesper Jørgensen, Katie Gagnon, student of Tom Ruth at Triumf, Canada, and, last but not least, to Tom himself. The people at the Edmonton PET centre, for beam time. David Schlyer and Rick Carson of BNL for access to the Tandem accelerator calibration shots. (author)

  8. Development of Beam Diagnostic Tools for Monitoring Cyclotron Beams at Production Intensities

    International Nuclear Information System (INIS)

    Jensen, Mikael

    2009-01-01

    This final report for the IAEA-CRP on “Improved High Current Liquid and Gas Targets for Cyclotron Produced Radioisotopes” reports the progress made as part of the Danish participation in the above CRP. Some of the work is the result of international, multi-institutional collaboration and/or research student education, and credit is hereby given to my former students Helge Thisgaard and Jesper Jørgensen, Katie Gagnon, student of Tom Ruth at Triumf, Canada, and, last but not least, to Tom himself. The people at the Edmonton PET centre, for beam time. David Schlyer and Rick Carson of BNL for access to the Tandem accelerator calibration shots. (author)

  9. Ultrahigh B doping (≤1022 cm-3) during Si(001) gas-source molecular-beam epitaxy: B incorporation, electrical activation, and hole transport

    International Nuclear Information System (INIS)

    Glass, G.; Kim, H.; Desjardins, P.; Taylor, N.; Spila, T.; Lu, Q.; Greene, J. E.

    2000-01-01

    Si(001) layers doped with B concentrations C B between 1x10 17 and 1.2x10 22 cm -3 (24 at %) were grown on Si(001)2x1 at temperatures T s =500-850 degree sign C by gas-source molecular-beam epitaxy from Si 2 H 6 and B 2 H 6 . C B increases linearly with the incident precursor flux ratio J B 2 H 6 /J Si 2 H 6 and B is incorporated into substitutional electrically active sites at concentrations up to C B * (T s ) which, for T s =600 degree sign C, is 2.5x10 20 cm -3 . At higher B concentrations, C B increases faster than J B 2 H 6 /J Si 2 H 6 and there is a large and discontinuous decrease in the activated fraction of incorporated B. However, the total activated B concentration continues to increase and reaches a value of N B =1.3x10 21 cm -3 with C B =1.2x10 22 cm -3 . High-resolution x-ray diffraction (HR-XRD) and reciprocal space mapping measurements show that all films, irrespective of C B and T s , are fully strained. No B precipitates or misfit dislocations were detected by HR-XRD or transmission electron microscopy. The lattice constant in the film growth direction a (perpendicular sign) decreases linearly with increasing C B up to the limit of full electrical activation and continues to decrease, but nonlinearly, with C B >C B * . Room-temperature resistivity and conductivity mobility values are in good agreement with theoretical values for B concentrations up to C B =2.5x10 20 and 2x10 21 cm -3 , respectively. All results can be explained on the basis of a model which accounts for strong B surface segregation to the second-layer with a saturation coverage θ B,sat of 0.5 ML (corresponding to C B =C B * ). At higher C B (i.e., θ B >θ B,sat ), B accumulates in the upper layer as shown by thermally programmed desorption measurements, and a parallel incorporation channel becomes available in which B is incorporated into substitutional sites as B pairs that are electrically inactive but have a low charge-scattering cross section. (c) 2000 The American Physical

  10. Effect of InGaAs interlayer on the properties of GaAs grown on Si (111) substrate by molecular beam epitaxy

    International Nuclear Information System (INIS)

    Wen, Lei; Gao, Fangliang; Li, Jingling; Guan, Yunfang; Wang, Wenliang; Zhou, Shizhong; Lin, Zhiting; Zhang, Xiaona; Zhang, Shuguang; Li, Guoqiang

    2014-01-01

    High-quality GaAs films have been epitaxially grown on Si (111) substrates by inserting an In x Ga 1−x As interlayer with proper In composition by molecular beam epitaxy (MBE). The effect of In x Ga 1−x As (0 < x < 0.2) interlayers on the properties of GaAs films grown on Si (111) substrates by MBE has been studied in detailed. Due to the high compressive strain between InGaAs and Si, InGaAs undergoes partial strain relaxation. Unstrained InGaAs has a larger lattice constant than GaAs. Therefore, a thin InGaAs layer with proper In composition may adopt a close lattice constant with that of GaAs, which is beneficial to the growth of high-quality GaAs epilayer on top. It is found that the proper In composition in In x Ga 1−x As interlayer of 10% is beneficial to obtaining high-quality GaAs films, which, on the one hand, greatly compensates the misfit stress between GaAs film and Si substrate, and on the other hand, suppresses the formation of multiple twin during the heteroepitaxial growth of GaAs film. However, when the In composition does not reach the proper value (∼10%), the In x Ga 1−x As adopts a lower strain relaxation and undergoes a lattice constant smaller than unstrained GaAs, and therefore introduces compressive stress to GaAs grown on top. When In composition exceeds the proper value, the In x Ga 1−x As will adopt a higher strain relaxation and undergoes a lattice constant larger than unstrained GaAs, and therefore introduces tensile stress to GaAs grown on top. As a result, In x Ga 1−x As interlayers with improper In composition introduces enlarged misfit stress to GaAs epilayers grown on top, and deteriorates the quality of GaAs epilayers. This work demonstrates a simple but effective method to grow high-quality GaAs epilayers and brings up a broad prospect for the application of GaAs-based optoelectronic devices on Si substrates

  11. Development of electron beam flue gas treatment technology

    International Nuclear Information System (INIS)

    Tokunaga, Okihiro; Namba, Hideki; Tanaka, Tadashi; Ogura, Yoshimi; Doi, Yoshitake; Aoki, Shinji; Izutsu, Masahiro.

    1995-01-01

    Smoke treatment system making use of electron beam irradiation made it possible to simultaneously eliminate SOx and NOn from exhaust gas. The fundamental study of the system was started in the seventies and at present, its application in practical use is under way. A pilot plant for the smoke treatment system was constructed in cooperation of Chubu Electric Power Company, Inc., Japan Atomic Energy Research Institute and Ebara Corporation and several tests with the actual exhaust gas were conducted during the period, Oct. 1992-Dec. 1993 and the treatment efficiency and the control capacity of this system was confirmed to be so high as the conventional systems and many engineering data were obtained. A high treatment efficiency (>94% for desulfurization and >80% for denitrification) was obtainable by choosing the optimum irradiation amount of electron beam and the optimum temperature of gas to treat. And this system was found superior from a financial aspect to the conventional smoke treatment system. (M.N.)

  12. Radioactive ion beam development for the SPIRAL 2 project

    International Nuclear Information System (INIS)

    Pichard, A.

    2010-01-01

    This thesis focuses on the study of radioactive ion beam production by the ISOL method for the SPIRAL 2 project. The production of light ion beams is studied and the potential in-target yields of two beams are appraised. The neutron-rich 15 C yield in an oxide target is estimated with simulations (MCNPx, EAF-07) and experimental data bases; the neutron-deficient 14 O yield is estimated thanks to a new measurement of the 12 C( 3 He, n) 14 O reaction excitation function. Based on thermal simulations, a first design of the production target is presented. This thermal study gives the necessary answers for the detailed design of the system able to reach a production yield 140 times higher than with SPIRAL 1. The production of radioactive ion beams coming from fissions in the UCx target is also studied and more particularly effusion and ionisation processes. A global study and an off-line tests campaign allow essential knowledge to the design of the surface ionisation source for SPIRAL 2 to be acquired. A first prototype of this ion source dedicated to alkali and alkaline-earth element production has been built and a thermal calibration performed. Ionisation efficiency and time response of the target-ion source system have been measured at different target temperatures and for different noble gases. These measurements allow evaluation of the impact of effusion and ionisation processes on the production efficiency of different alkali and noble gases isotopes as a function of their half-life. (author) [fr

  13. Development of electron beam flue gas treatment technology

    International Nuclear Information System (INIS)

    Tanaka, T.

    1995-01-01

    The electron beam flue gas treatment technology is expected to bring many advantages such as the simultaneous reduction of SO x and NO x emissions, a dry process without waste water, valuable fertilizer byproducts, etc. In order to verify the feasibility and performances of the process, a practical application test is carried out with a pilot plant which treats the actual flue gas from a coal-fired boiler. Results are presented. 4 figs., 2 tabs

  14. Al2O3 e-Beam Evaporated onto Silicon (100)/SiO2, by XPS

    Energy Technology Data Exchange (ETDEWEB)

    Madaan, Nitesh; Kanyal, Supriya S.; Jensen, David S.; Vail, Michael A.; Dadson, Andrew; Engelhard, Mark H.; Samha, Hussein; Linford, Matthew R.

    2013-09-25

    We report the XPS characterization of a thin film of Al2O3 (35 nm) deposited via e-beam evaporation onto silicon (100). The film was characterized with monochromatic Al Ka radiation. An XPS survey scan, an Al 2p narrow scan, and the valence band spectrum were collected. The Al2O3 thin film is used as a diffusion barrier layer for templated carbon nanotube (CNT) growth in the preparation of microfabricated thin layer chromatography plates.

  15. Development of Solar Grade Silicon (SoG-Si) Feedstock by Recycling SoG-Si Wastes

    Energy Technology Data Exchange (ETDEWEB)

    Lifeng Zhang; Anping Dong; Lucas Nana Wiredu Damoah

    2013-01-24

    Experiment results of EM separation show that the non-metallic inclusions were successfully pushed to the boundary layer of the crucible under EM force. Larger frequency and smaller current generate smaller thickness of accumulated inclusions. More detailed EM separation experiments are undergoing to investigate the factors that affect the removal efficient of inclusions from SoG-Si

  16. Development of an MeV ion beam lithography system in Jyvaeskylae

    Energy Technology Data Exchange (ETDEWEB)

    Gorelick, Sergey [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FIN-40014 (Finland)]. E-mail: Sergey.Gorelick@phys.jyu.fi; Ylimaeki, Tommi [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FIN-40014 (Finland); Sajavaara, Timo [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FIN-40014 (Finland); Laitinen, Mikko [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FIN-40014 (Finland); Sagari, A.R.A. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FIN-40014 (Finland); Whitlow, Harry J. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FIN-40014 (Finland)

    2007-07-15

    A lithographic facility for writing patterns with ion beams from cyclotron beams is under development for the Jyvaeskylae cyclotron. Instead of focusing and deflecting the beam with electrostatic and magnetic fields a different approach is used. Here a small rectangular beam spot is defined by the shadow of a computer-controlled variable aperture in close proximity to the sample. This allows parallel exposure of rectangular pattern elements of 5-500 {mu}m side with protons up to 6 MeV and heavy ions ({sup 20}Ne, {sup 85}Kr) up to few 100 MeV. Here we present a short overview of the system under construction and development of the aperture design, which is a critical aspect for all ion beam lithography systems.

  17. Silicon-substituted hydroxyapatite coating with Si content on the nanotube-formed Ti–Nb–Zr alloy using electron beam-physical vapor deposition

    International Nuclear Information System (INIS)

    Jeong, Yong-Hoon; Choe, Han-Cheol; Brantley, William A.

    2013-01-01

    The purpose of this study was to investigate the electrochemical characteristics of silicon-substituted hydroxyapatite coatings on the nanotube-formed Ti–35Nb–10Zr alloy. The silicon-substituted hydroxyapatite (Si–HA) coatings on the nanotube structure were deposited by electron beam-physical vapor deposition and anodization methods, and biodegradation properties were analyzed by potentiodynamic polarization and electrochemical impedance spectroscopy measurement. The surface characteristics were analyzed by field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction (XRD). The Si–HA layers were deposited with rough features having highly ordered nanotube structures on the titanium alloy substrate. The thickness of the Si–HA coating was less than that of the HA coating. The XRD results confirmed that the Si–HA coating on the nanotube structure consisted of TiO 2 anatase, TiO 2 rutile, hydroxyapatite, and calcium phosphate silicate. The Si–HA coating surface exhibited lower I corr than the HA coating, and the polarization resistance was increased by substitution of silicon in hydroxyapatite. - Highlights: • Silicon substituted hydroxyapatite (Si–HA) was coated on nanotubular titanium alloy. • The Si–HA coating thickness was less than single hydroxyapatite (HA) coating. • Si–HA coatings consisted of TiO 2 , HA, and Ca 5 (PO 4 ) 2 SiO 4 . • Polarization resistance of the coating was increased by Si substitution in HA

  18. High Al-content AlxGa1-xN epilayers grown on Si substrate by plasma-assisted molecular beam epitaxy

    International Nuclear Information System (INIS)

    Hussein, A.SH.; Thahab, S.M.; Hassan, Z.; Chin, C.W.; Abu Hassan, H.; Ng, S.S.

    2009-01-01

    The microstructure and optical properties of Al x Ga 1-x N/GaN/AlN films on Si (1 1 1) substrate grown by plasma-assisted molecular beam epitaxy (MBE) have been studied and investigated. Reflection high energy electron diffraction (RHEED), scanning electron microscopy (SEM), high-resolution X-ray diffraction (HR-XRD), energy dispersive X-ray spectroscopy (EDS) line analysis and photoluminescence (PL) were used to investigate a reconstruction pattern, cross-section, mole fraction and crystalline quality of the heterostructure. By applying the Vegard's law, a high Al-mole fraction of Al x Ga 1-x N sample with value of 0.43 has been obtained and compared with EDS line analysis measurement value. PL spectrum has exhibited a sharp and intense band edge emission of GaN with the absence of yellow emission band, indicating good crystal quality of the Al x Ga 1-x N has been successfully grown on Si substrate.

  19. Correlation between morphological defects, electron beam-induced current imaging, and the electrical properties of 4H-SiC Schottky diodes

    International Nuclear Information System (INIS)

    Wang, Y.; Ali, G.N.; Mikhov, M.K.; Vaidyanathan, V.; Skromme, B.J.; Raghothamachar, B.; Dudley, M.

    2005-01-01

    Defects in SiC degrade the electrical properties and yield of devices made from this material. This article examines morphological defects in 4H-SiC and defects visible in electron beam-induced current (EBIC) images and their effects on the electrical characteristics of Schottky diodes. Optical Nomarski microscopy and atomic force microscopy were used to observe the morphological defects, which are classified into 26 types based on appearance alone. Forward and reverse current-voltage characteristics were used to extract barrier heights, ideality factors, and breakdown voltages. Barrier heights decrease about linearly with increasing ideality factor, which is explained by discrete patches of low barrier height within the main contact. Barrier height, ideality, and breakdown voltage all degrade with increasing device diameter, suggesting that discrete defects are responsible. Electroluminescence was observed under reverse bias from microplasmas associated with defects containing micropipes. EBIC measurements reveal several types of features corresponding to recombination centers. The density of dark spots observed by EBIC correlates strongly with ideality factor and barrier height. Most morphological defects do not affect the reverse characteristics when no micropipes are present, but lower the barrier height and worsen the ideality factor. However, certain multiple-tailed defects, irregularly shaped defects and triangular defects with 3C inclusions substantially degrade both breakdown voltage and barrier height, and account for most of the bad devices that do not contain micropipes. Micropipes in these wafers are also frequently found to be of Type II, which do not run parallel to the c axis

  20. Hydrogen Charging Effects in Pd/Ti/TiO2/Ti Thin Films Deposited on Si(111 Studied by Ion Beam Analysis Methods

    Directory of Open Access Journals (Sweden)

    K. Drogowska

    2012-01-01

    Full Text Available Titanium and titanium dioxide thin films were deposited onto Si(111 substrates by magnetron sputtering from a metallic Ti target in a reactive Ar+O2 atmosphere, the composition of which was controlled by precision gas controllers. For some samples, 1/3 of the surface was covered with palladium using molecular beam epitaxy. Chemical composition, density, and layer thickness of the layers were determined by Auger electron spectroscopy (AES and Rutherford backscattering spectrometry (RBS. The surface morphology was studied using high-resolution scanning electron microscopy (HRSEM. After deposition, smooth, homogenous sample surfaces were observed. Hydrogen charging for 5 hours under pressure of 1 bar and at temperature of 300°C results in granulation of the surface. Hydrogen depth profile was determined using secondary ion mass spectrometry (SIMS and nuclear Reaction Analysis (N-15 method, using a 15N beam at and above the resonance energy of 6.417 MeV. NRA measurements proved a higher hydrogen concentration in samples with partially covered top layers, than in samples without palladium. The highest value of H concentration after charging was about 50% (in the palladium-covered part and about 40% in titanium that was not covered by Pd. These values are in good agreement with the results of SIMS measurements.

  1. Assessment of laser ablation techniques in a-si technologies for position-sensor development

    Science.gov (United States)

    Molpeceres, C.; Lauzurica, S.; Ocana, J. L.; Gandia, J. J.; Urbina, L.; Carabe, J.

    2005-07-01

    Laser micromachining of semiconductor and Transparent Conductive Oxides (TCO) materials is very important for the practical applications in photovoltaic industry. In particular, a problem of controlled ablation of those materials with minimum of debris and small heat affected zone is one of the most vital for the successful implementation of laser micromachining. In particular, selective ablation of thin films for the development of new photovoltaic panels and sensoring devices based on amorphous silicon (a-Si) is an emerging field, in which laser micromachining systems appear as appropriate tools for process development and device fabrication. In particular, a promising application is the development of purely photovoltaic position sensors. Standard p-i-n or Schottky configurations using Transparent Conductive Oxides (TCO), a-Si and metals are especially well suited for these applications, appearing selective laser ablation as an ideal process for controlled material patterning and isolation. In this work a detailed study of laser ablation of a widely used TCO, Indium-tin-oxide (ITO), and a-Si thin films of different thicknesses is presented, with special emphasis on the morphological analysis of the generated grooves. The profiles of ablated grooves have been studied in order to determine the best processing conditions, i.e. laser pulse energy and wavelength, and to asses this technology as potentially competitive to standard photolithographic processes. The encouraging results obtained, with well defined ablation grooves having thicknesses in the order of 10 μm both in ITO and a-Si, open up the possibility of developing a high-performance double Schottky photovoltaic matrix position sensor.

  2. Development of a radio-frequency quadrupole cooler for high beam currents

    Science.gov (United States)

    Boussaid, Ramzi; Ban, G.; Quéméner, G.; Merrer, Y.; Lorry, J.

    2017-12-01

    The SHIRaC prototype is a recently developed radio-frequency quadrupole (RFQ) beam cooler with an improved optics design to deliver the required beam quality to a high resolution separator (HRS). For an isobaric separation of isotopes, the HRS demands beams with emittance not exceeding 3 π mm mrad and longitudinal energy spread ˜1 eV . Simulation studies showed a significant contribution of the buffer gas diffusion, space charge effect and mainly the rf fringe field to degrade the achieved beam quality at the RFQ exit. A miniature rf quadrupole (μ RFQ ) has been implemented at that exit to remove the degrading effects and provide beams with 1 eV of energy spread and around 1.75 π mm mrad of emittance for 4 Pa gas pressure. This solution enables also to transmit more than 60% of the incoming ions for currents up to 1 μ A . Detailed studies of this development are presented and discussed in this paper. Transport of beams from SHIRaC towards the HRS has been done with an electrostatic quadrupole triplet. Simulations and first experimental tests showed that more than 95% of ions can reach the HRS. Because SPIRAL-2 beams are of high current and very radioactive, the buffer gas will be highly contaminated. Safe maintenance of the SHIRaC beam line needs exceptional treatment of radioactive contaminants. For that, special vinyl sleep should be mounted on elements to be maintained. A detailed maintenance process will be presented.

  3. Technology roadmap for development of SiC sensors at plasma processes laboratory

    Directory of Open Access Journals (Sweden)

    Mariana Amorim Fraga

    2010-08-01

    Full Text Available Recognizing the need to consolidate the research and development (R&D activities in microelectronics fields in a strategic manner, the Plasma Processes Laboratory of the Technological Institute of Aeronautics (LPP-ITA has established a technology roadmap to serve as a guide for activities related to development of sensors based on silicon carbide (SiC thin films. These sensors have also potential interest to the aerospace field due to their ability to operate in harsh environment such as high temperatures and intense radiation. In the present paper, this roadmap is described and presented in four main sections: i introduction, ii what we have already done in the past, iii what we are doing in this moment, and iv our targets up to 2015. The critical technological issues were evaluated for different categories: SiC deposition techniques, SiC processing techniques for sensors fabrication and sensors characterization. This roadmap also presents a shared vision of how R&D activities in microelectronics should develop over the next five years in our laboratory.

  4. Development of Core Simulator (CoSi) for APR1400 And Analysis of LPPT Result using APR1400-CoSi

    International Nuclear Information System (INIS)

    Moon, Sang-Rae; Kim, Yong-Bae; Lee, Eun-Ki

    2014-01-01

    According to NRC guidelines, Low Power Physics Test (LPPT) is required to be performed in low temperature/low pressure (160 .deg. C/42.2 kg/cm 2 ) as well as NOT/NOP (291.3 .deg. C/158.2 kg/cm 2 ) because Shin-Kori Unit 3 is FOAK nuclear power plant. Low Power Physics Test (LPPT) is essential to verify the nuclear design and robustness of reactor safety. LPPT consists of initial criticality, Point of Adding Heat (POAH), All Rod Out (ARO) Boron Concentration, Isothermal Temperature Coefficient (ITC), Control Rod Worth measurements and so on. KHNP-CRI has developed the Core Simulator for APR1400 (APR1400-CoSi) in order to improve the ability performing the LPPT. Especially, APR1400-CoSi has enhanced capability to calculate the full Core neutronic parameters by revising RAST-K that is three dimensional real time core kinetic program. APR1400-CoSi has been developed for education-training of Low Power Physics Test(LPPT). Particularly, APR1400-CoSi has an enhanced capability to calculate the full core neutronic parameters by revising RAST-K which is a three dimensional real time core kinetics program. Low Power Physics Test (LPPT) was performed using APR1400-CoSi and the results showed very similar values with the predicted ones. In other words, the initial core model of Shin-Kori Unit 3 in APR1400-CoSi system has been verified to be appropriate enough. Also, it was confirmed that the test range of Low Power Physics Test (LPPT) reamains effective even though the largest incremental bank reactivity is inserted in core by analyzing the power change during the rod SWAP test

  5. RF ion source development for neutral beam application

    International Nuclear Information System (INIS)

    Leung, K.N.; Ehlers, K.W.; Kippenhan, D.; Vella, M.C.

    1983-11-01

    At Lawrence Berkeley Laboratory, a 24 x 24 cm 2 RF source has been tested with beam acceleration. Recently, we have been investigating the characteristics of plasmas generated with different kinds of antenna coatings. The antenna coil was installed inside a cylindrical multicusp source (20-cm diam by 24-cm long) and was driven by a 500 W amplifier. A tiny light bulb filament was used to start a background plasma. The RF was then switched on and a steady-state hydrogen plasma of moderate density (n approx. = 10 11 /cm 3 ) could be sustained even with the filament turned off

  6. Development of a micro-tomography technique by ion beams

    International Nuclear Information System (INIS)

    Moretto, Ph.; Michelet, C.

    1997-01-01

    The capability for an ion beam to penetrate easily the matter is an original feature for the nuclear microprobe analysis when compared to other techniques. Information in death of the sample can thus be obtained. Scanning Transmission Ion Microscopy (STIM) takes advantage of this capability to provide two dimensional maps of the sample thickness. Cross-sectional images of an object may be calculated from a set of STIM projections allowing the determination of the three-dimensional structure. This is the principle of STIM-Tomography. When PIXE analysis is carried out rotating the object under investigation, the elemental 3-D chemical distribution may also be elucidated at a microscopic scale. (authors)

  7. Emission control of InGaN nanocolumns grown by molecular-beam epitaxy on Si(111) substrates

    International Nuclear Information System (INIS)

    Albert, S.; Bengoechea-Encabo, A.; Sanchez-Garcia, M. A.; Calleja, E.; Lefebvre, P.; Jahn, U.; Trampert, A.

    2011-01-01

    This work studies the effect of the growth temperature on the morphology and emission characteristics of self-assembled InGaN nanocolumns grown by plasma assisted molecular beam epitaxy. Morphology changes are assessed by scanning electron microscopy, while emission is measured by photoluminescence. Within the growth temperature range of 750 to 650 deg. C, an increase in In incorporation for decreasing temperature is observed. This effect allows tailoring the InGaN nanocolumns emission line shape by using temperature gradients during growth. Depending on the gradient rate, span, and sign, broad emission line shapes are obtained, covering the yellow to green range, even yielding white emission.

  8. Developing an expert system to control a beam line at the Los Alamos Meson Physics Facility

    International Nuclear Information System (INIS)

    Clearwater, S.H.; Papcun, G.; Clark, D.A.

    1985-01-01

    High energy particle experiments require an accelerator as a source of high energy particles. To increase the productivity of an accelerator facility, we wish to develop an expert system to control beam lines. Expert Systems are a branch of Artificial Intelligence where a computer program performs tasks requiring human expertise. Unlike most expert systems we have a physical model underlying our beam line and this model can be used with the expert system to improve performance. The development of the expert system will lead to an increased understanding of the beam line as well as the possibility of state-of-the-art expert system building

  9. Research summary: experiments which use the X-ray charge changed beam apparatus and equipment development

    International Nuclear Information System (INIS)

    Shafroth, S.M.; Clark, M.W.; Swenson, J.K.; Anthony, J.M.; Reed, M.

    1985-01-01

    Several atomic physics experiments are briefly described. These include resonant and nonresonant transfer excitation, simultaneous excitation and ionization, bare H-like and He-like beam experiments and single and double electron capture. Equipment development is also discussed

  10. Development of accurate techniques for controlling polarization of a long wavelength neutron beam in very low magnetic fields. I

    International Nuclear Information System (INIS)

    Kawai, Takeshi; Ebisawa, Toru; Tasaki, Seiji; Akiyoshi, Tsunekazu; Eguchi, Yoshiaki; Hino, Masahiro; Achiwa, Norio.

    1995-01-01

    The purpose of our study is to develop accurate techniques for controlling polarization of a long wavelength neutron beam and to make a thin-film dynamical spin-flip device operated in magnetizing fields less than 100 gauss and in a shorter switching time up to 20 kHz. The device would work as a chopper for a polarized neutron beam and as a magnetic switching device for a multilayer neutron interferometer. We have started to develop multilayer polarizing mirrors functioning under magnetizing fields less than 100 gauss. The multilayers of Permalloy-Ge and Fe-Ge have been produced using the evaporation method under magnetizing fields of about 100 gauss parallel to the Si-wafer substrate surface. The hysteresis loop for in-plane magnetization of the multilayers were measured to discuss their feasibilities for the polarizing device functioning under very low magnetizing fields. The polarizing efficiencies of Fe-Ge and Permalloy-Ge multilayers were 95 % and 91 % with reflectivities of 50 % and 66 % respectively under magnetizing fields of 80 gauss. The report also discusses problems in applying these multilayer polarizing mirrors to ultracold neutrons. (author)

  11. Development of an IH-type linac for the acceleration of high current heavy ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Haehnel, Jan Hendrik

    2017-07-20

    The Facility for Antiproton and Ion Research (FAIR) at GSI Darmstadt will provide unprecedented intensities of protons and heavy ions up to uranium at energies of up to 29 GeV for protons and 2.7 GeV/u for U{sup 28+}. To achieve high intensities in the synchrotron accelerators, high beam currents have to be provided by the injector linear accelerators. High current heavy ion beams are provided by the Universal Linear Accelerator (UNILAC), which in its current state will not be able to provide the required FAIR beam currents. This thesis deals with the development of upgrades for the UNILAC to ensure its high current capability. The first improvement is a matching section (MEBT) for the interface between the RFQ and the IH-DTL of the existing high current injector HSI at the UNILAC. With this new MEBT section, particle losses are eliminated and the overall beam quality is improved. As a second improvement, a complete replacement of the existing Alvarez-DTL is presented. A combination of efficient IH-type cavities and KONUS beam dynamics results in a reduction of the linac length from about 60 m (Alvarez) to just 23 m (new IH-DTL) while providing the same energy and fulfilling FAIR requirements of a high beam current and beam quality. This thesis contains a detailed beam dynamics design of the new linac including some fundamental investigations of the KONUS beam dynamics concept. A cross-check of the beam dynamics design was performed with two independent multi-particle simulation codes. Detailed error studies were conducted to investigate the influence of manufacturing, alignment and operating errors on the beam dynamics performance. Additionally, all five linac cavities were designed, optimized, and their RF parameters including power requirements calculated to provide a comprehensive linac design.

  12. Development of an IH-type linac for the acceleration of high current heavy ion beams

    International Nuclear Information System (INIS)

    Haehnel, Jan Hendrik

    2017-01-01

    The Facility for Antiproton and Ion Research (FAIR) at GSI Darmstadt will provide unprecedented intensities of protons and heavy ions up to uranium at energies of up to 29 GeV for protons and 2.7 GeV/u for U 28+ . To achieve high intensities in the synchrotron accelerators, high beam currents have to be provided by the injector linear accelerators. High current heavy ion beams are provided by the Universal Linear Accelerator (UNILAC), which in its current state will not be able to provide the required FAIR beam currents. This thesis deals with the development of upgrades for the UNILAC to ensure its high current capability. The first improvement is a matching section (MEBT) for the interface between the RFQ and the IH-DTL of the existing high current injector HSI at the UNILAC. With this new MEBT section, particle losses are eliminated and the overall beam quality is improved. As a second improvement, a complete replacement of the existing Alvarez-DTL is presented. A combination of efficient IH-type cavities and KONUS beam dynamics results in a reduction of the linac length from about 60 m (Alvarez) to just 23 m (new IH-DTL) while providing the same energy and fulfilling FAIR requirements of a high beam current and beam quality. This thesis contains a detailed beam dynamics design of the new linac including some fundamental investigations of the KONUS beam dynamics concept. A cross-check of the beam dynamics design was performed with two independent multi-particle simulation codes. Detailed error studies were conducted to investigate the influence of manufacturing, alignment and operating errors on the beam dynamics performance. Additionally, all five linac cavities were designed, optimized, and their RF parameters including power requirements calculated to provide a comprehensive linac design.

  13. Application of high power modulated intense relativistic electron beams for development of Wake Field Accelerator

    International Nuclear Information System (INIS)

    Friedman, M.

    1989-01-01

    This final Progress Report addresses DOE-sponsored research on the development of future high-gradient particle accelerators. The experimental and the theoretical research, which lasted three years, investigated the Two Beam Accelerator (TBA). This high-voltage-gradient accelerator was powered by a modulated intense relativistic electron beam (MIREB) of power >10 10 watts. This research was conceived after a series of successful experiments performed at NRL generating and using MIREBs. This work showed that an RF structure could be built which was directly powered by a modulated intense relativistic electron beam. This structure was then used to accelerate a second electron beam. At the end of the three year project the proof-of-principle accelerator demonstrated the generation of a high current beam of electrons with energy >60 MeV. Scaling laws needed to design practical devices for future applications were also derived

  14. Development of a multi-lane X-ray mirror providing variable beam sizes

    Energy Technology Data Exchange (ETDEWEB)

    Laundy, D., E-mail: david.laundy@diamond.ac.uk; Sawhney, K.; Nistea, I.; Alcock, S. G.; Pape, I.; Sutter, J.; Alianelli, L.; Evans, G. [Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0DE (United Kingdom)

    2016-05-15

    Grazing incidence mirrors are used on most X-ray synchrotron beamlines to focus, collimate or suppress harmonics. Increasingly beamline users are demanding variable beam shapes and sizes at the sample position. We have now developed a new concept to rapidly vary the beam size and shape of a focused X-ray beam. The surface of an elliptically figured mirror is divided into a number of laterally separated lanes, each of which is given an additional longitudinal height profile calculated to shape the X-ray beam to a top-hat profile in the focal plane. We have now fabricated two prototype mirrors and present the results of metrology tests and measurements made with one of the mirrors focusing the X-rays on a synchrotron beamline. We envisage that such mirrors could be widely applied to rapid beam-size switching on many synchrotron beamlines.

  15. Treatment facilities, human resource development, and future prospect of particle beam therapy

    International Nuclear Information System (INIS)

    Tamaki, Tomoaki; Nakano, Takashi

    2015-01-01

    The number of particle beam therapy facilities is increasing globally. Among the countries practicing particle beam therapy, Japan is one of the leading countries in the field with four operating carbon-ion therapy facilities and ten operating proton therapy facilities. With the increasing number of particle beam therapy facilities, the human resource development is becoming extremely important, and there has been many such efforts including the Gunma University Program for Cultivating Global Leaders in Heavy Ion Therapeutics and Engineering, which aimed to educate and train the radiation oncologists, medical physicists, accelerator engineers, and radiation biologists to become global leaders in the field of particle beam therapy. In the future, the benefit and effectiveness of particle beam therapy should be discussed and elucidated objectively in a framework of comprehensive cancer care. (author)

  16. Developing of the protocol for electron beam food irradiation facility

    International Nuclear Information System (INIS)

    Petreska, Svetlana

    2012-01-01

    By establishing the needs for institution of new technologies in the process of food processing, in this case a randomized choice of electron beam accelerator facility, arises the need for designing a protocol for safe and secure performance of the facility. The protocol encompasses safety and security measures for protection from ionizing radiation of the individuals who work at the facility, as well as, the population and the environment in the immediate neighborhood of the facility. Thus, the adopted approach is the establishment of appropriate systems responding to the protocol. Dosimetry system, which includes appropriate procedures for accurate measure and recording of the absorbed dose values, according to the provisions for protection from ionizing radiation. Ionizing radiation protection system and providing the safety and security of the facility for food processing by means of ionizing radiation. System for providing quality and safety control of the facility for food processing by means of ionizing radiation. Pursuant to the designed a protocol for safe and secure performance of the facility for electron beam food processing, contributes to protection against ionizing radiation as occupationally exposed persons as well the population. (Author)

  17. Development of a classical force field for the oxidized Si surface: application to hydrophilic wafer bonding.

    Science.gov (United States)

    Cole, Daniel J; Payne, Mike C; Csányi, Gábor; Spearing, S Mark; Colombi Ciacchi, Lucio

    2007-11-28

    We have developed a classical two- and three-body interaction potential to simulate the hydroxylated, natively oxidized Si surface in contact with water solutions, based on the combination and extension of the Stillinger-Weber potential and of a potential originally developed to simulate SiO(2) polymorphs. The potential parameters are chosen to reproduce the structure, charge distribution, tensile surface stress, and interactions with single water molecules of a natively oxidized Si surface model previously obtained by means of accurate density functional theory simulations. We have applied the potential to the case of hydrophilic silicon wafer bonding at room temperature, revealing maximum room temperature work of adhesion values for natively oxidized and amorphous silica surfaces of 97 and 90 mJm(2), respectively, at a water adsorption coverage of approximately 1 ML. The difference arises from the stronger interaction of the natively oxidized surface with liquid water, resulting in a higher heat of immersion (203 vs 166 mJm(2)), and may be explained in terms of the more pronounced water structuring close to the surface in alternating layers of larger and smaller densities with respect to the liquid bulk. The computed force-displacement bonding curves may be a useful input for cohesive zone models where both the topographic details of the surfaces and the dependence of the attractive force on the initial surface separation and wetting can be taken into account.

  18. Development and characterization of Si3N4 coated AlCrN ceramic cutting tool

    International Nuclear Information System (INIS)

    Souza, J.V.C.; Nono, M.C.A.; Martins, G.V.; Machado, J.P.B.; Silva, O.M.M.

    2009-01-01

    Nowadays, silicon nitride based cutting tools are used to machine cast iron from the automotive industry and nickel superalloys from the aero industries. Advances in manufacturing technologies (increased cutting speeds, dry machining, etc.) induced the fast commercial growth of physical vapor deposition (PVD) coatings for cutting tools, in order to increase their life time. In this work, a new composition of the Si 3 N 4 ceramic cutting tool was developed, characterized and subsequently coated, using a PVD process, with aluminum chromium nitride (AlCrN). The Si 3 N 4 substrate properties were analyzed by XRD, AFM, hardness and fracture toughness. The AlCrN coating was analyzed by AFM, grazing incidence X-ray diffraction (GIXRD) and hardness. The results showed that this PVD coating could be formed homogeneously, without cracks and promoted a higher surface hardness to the insert and consequently it can produce a better wear resistance during its application on high speed machining. (author)

  19. Development of an integrated response generator for Si/CdTe semiconductor Compton cameras

    International Nuclear Information System (INIS)

    Odaka, Hirokazu; Sugimoto, Soichiro; Ishikawa, Shin-nosuke; Katsuta, Junichiro; Koseki, Yuu; Fukuyama, Taro; Saito, Shinya; Sato, Rie; Sato, Goro; Watanabe, Shin

    2010-01-01

    We have developed an integrated response generator based on Monte Carlo simulation for Compton cameras composed of silicon (Si) and cadmium telluride (CdTe) semiconductor detectors. In order to construct an accurate detector response function, the simulation is required to include a comprehensive treatment of the semiconductor detector devices and the data processing system in addition to simulating particle tracking. Although CdTe is an excellent semiconductor material for detection of soft gamma rays, its ineffective charge transport property distorts its spectral response. We investigated the response of CdTe pad detectors in the simulation and present our initial results here. We also performed the full simulation of prototypes of Si/CdTe semiconductor Compton cameras and report on the reproducibility of detection efficiencies and angular resolutions of the cameras, both of which are essential performance parameters of astrophysical instruments.

  20. Development of an intermediate energy heavy-ion micro-beam irradiation system

    International Nuclear Information System (INIS)

    Song Mingtao; Wang Zhiguang; He Yuan; Gao Daqing; Yang Xiaotian; Liu Jie; Su Hong; Man Kaidi; Sheng Li'na

    2008-01-01

    The micro-beam irradiation system, which focuses the beam down the micron order and precisely delivers a predefined number of ions to a predefined spot of micron order, is a powerful tool for radio-biology, radio-biomedicine and micromachining. The Institute of Modern Physics of Chinese Academy of Sciences is developing a heavy-ion micro-beam irradiation system up to intermediate energy. Based on the intermediate and low energy beam provided by Heavy Ion Research Facility of Lanzhou, the micro-beam system takes the form of the magnetic focusing. The heavy-ion beam is conducted to the basement by a symmetrical achromatic system consisting of two vertical bending magnets and a quadrupole in between. Then a beam spot of micron order is formed by magnetic triplet quadrupole of very high gradient. The sample can be irradiated either in vacuum or in the air. This system will be the first opening platform capable of providing heavy ion micro-beam, ranging from low (10 MeV/u) to intermediate energy (100 MeV/u), for irradiation experiment with positioning and counting accuracy. Target material may be biology cell, tissue or other non-biological materials. It will be a help for unveiling the essence of heavy-ion interaction with matter and also a new means for exploring the application of heavy-ion irradiation. (authors)