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Sample records for performance carbon beam

  1. Electron Beam Exposure of Thermal Control Paints on Carbon-Carbon and Carbon-Polyimide Composites

    NASA Technical Reports Server (NTRS)

    Jaworske, Donald A.

    2006-01-01

    Carbon-carbon and carbon-polyimide composites are being considered for use as radiator face sheets or fins for space radiator applications. Several traditional white thermal control paints are being considered for the surface of the composite face sheets or fins. One threat to radiator performance is high energy electrons. The durability of the thermal control paints applied to the carbon-carbon and carbon-polyimide composites was evaluated after extended exposure to 4.5 MeV electrons. Electron exposure was conducted under argon utilizing a Mylar(TradeMark) bag enclosure. Solar absorptance and infrared emittance was evaluated before and after exposure to identify optical properties degradation. Adhesion of the paints to the carbon-carbon and carbon-polyimide composite substrates was also of interest. Adhesion was evaluated on pristine and electron beam exposed coupons using a variation of the ASTM D-3359 tape test. Results of the optical properties evaluation and the adhesion tape tests are summarized.

  2. Scanned Carbon Pencil Beams for Tumor Therapy

    NASA Astrophysics Data System (ADS)

    Gemmel, A.; Saito, N.; Chaudhri, N.; Lü; chtenborg, R.; Schardt, D.; Rietzel, E.; Bert, Ch.

    2009-03-01

    At GSI a fully active beam application has been developed for tumor therapy with carbon ions. In this so-called rasterscan system the tumor volume is typically split into ˜60 slices of iso-energies taken from a list of 252 energies ranging from ˜90-430 MeV/u (range: 1.8-30.7 cm). The energies can be combined with variable beam diameters and intensities. For each iso-energy slice beam is requested from the synchrotron and delivered as a narrow pencil beam (beam's full width at half maximum 3-10 mm). For lateral target coverage this pencil beam is deflected to several hundreds of grid positions per iso-energy slice by orthogonal dipole magnets. At each grid position an optimized number of particles is deposited intensity-controlled, i.e. ionization chambers monitor the dose deposition and trigger deflection to the next grid position once the required dose level is achieved. This method allows intensity-modulated treatment fields necessary to deposit a uniform biological effective dose. Additionally, it allows for simultaneous optimization of multiple fields that allow better sparing of organs at risk partially or fully surrounded by the tumor. Scanned beam delivery facilitates target conformal and homogeneous dose delivery for stationary targets. For tumors located in the head & neck as well as tumors in the pelvic region very promising results were achieved in the carbon therapy pilot project started at GSI in 1993. A comparable project is conducted at Paul-Scherrer-Institut (PSI) in Switzerland with a scanned proton beam. One of the current research topics is the treatment of moving targets such as lung tumors. Scanned beam delivery requires but also offers possibilities to conformably irradiate moving target sites.

  3. Joining Carbon-Carbon Composites and High-Temperature Materials with High Energy Electron Beams

    NASA Technical Reports Server (NTRS)

    Goodman, Daniel; Singler, Robert

    1998-01-01

    1. Program goals addressed during this period. Experimental work was directed at formation of a low-stress bond between carbon- carbon and aluminum, with the objective of minimizing the heating of the aluminum substrate, thereby minimizing stresses resulting from the coefficient of thermal expansion (CTE) difference between the aluminum and carbon-carbon. A second objective was to form a bond between carbon-carbon and aluminum with good thermal conductivity for electronic thermal management (SEM-E) application. 2. Substrates and joining materials selected during this period. Carbon-Carbon Composite (CCC) to Aluminum. CCC (Cu coated) to Aluminum. Soldering compounds based on Sn/Pb and Sn/Ag/Cu/Bi compositions. 3. Soldering experiments performed. Conventional techniques. High Energy Electron Beam (HEEB) process.

  4. Focused Ion Beam Microscopy of ALH84001 Carbonate Disks

    NASA Astrophysics Data System (ADS)

    Thomas-Keprta, K. L.; Clemett, S. J.; Bazylinski, D. A.; Kirschvink, J. L.; McKay, D. S.; Vali, H.; Gibson, E. K., Jr.; Romanek, C. S.

    2005-03-01

    Our aim is to understand the mechanism(s) of formation of carbonate assemblages in ALH84001. We present here analyses by transmission electron microscopy (TEM) of carbonate thin sections produced by both focused ion beam (FIB) sectioning and ultramicrotomy.

  5. Performance Comparison: Superbeams, Beta Beams, Neutrino Factory

    SciTech Connect

    Winter, Walter

    2011-10-06

    In this talk, the performance comparison among superbeams (SB), beta beams (BB), and the Neutrino Factory (NF) is discussed. The ingredients to such a comparison are described, and the optimization and status of BB and NF are addressed. Finally, one example for the performance comparison is shown.

  6. Beam profile effects on NPB performance

    SciTech Connect

    Leclaire, R.J. Jr.; Bunker, W.J.

    1988-03-01

    A comparison of neutral particle beam (NPB) brightness for various neutral beam profiles indicates that the widely used assumption of a Gaussian profile may be misleading for collisional neutralizers. An analysis of available experimental evidence shows that lower peaks and higher tails, compared to a Gaussian beam profile, are observed out of collisional neutralizers, which implies that peak brightness is over estimated, and for a given NPB platform-to-target range, the beam current (power), dwell time or some combination of such engagement parameters would have to be altered to maintain a fixed dose on the target. Based on the present analysis, this factor is nominally about 2.4 but may actually be as low as 1.8 or as high as 8. This is an important consideration in estimating NPB constellation performance in SDI engagement contexts.

  7. Shunting arc plasma source for pure carbon ion beam.

    PubMed

    Koguchi, H; Sakakita, H; Kiyama, S; Shimada, T; Sato, Y; Hirano, Y

    2012-02-01

    A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA∕mm(2) at the peak of the pulse. PMID:22380206

  8. Geant4 simulations of proton beam transport through a carbon or beryllium degrader and following a beam line.

    PubMed

    van Goethem, M J; van der Meer, R; Reist, H W; Schippers, J M

    2009-10-01

    Monte Carlo simulations based on the Geant4 simulation toolkit were performed for the carbon wedge degrader used in the beam line at the Center of Proton Therapy of the Paul Scherrer Institute (PSI). The simulations are part of the beam line studies for the development and understanding of the GANTRY2 and OPTIS2 treatment facilities at PSI, but can also be applied to other beam lines. The simulated stopping power, momentum distributions at the degrader exit and beam line transmission have been compared to accurate benchmark measurements. Because the beam transport through magnetic elements is not easily modeled using Geant4a connection to the TURTLE beam line simulation program was made. After adjusting the mean ionization potential of the carbon degrader material from 78 eV to 95 eV, we found an accurate match between simulations and benchmark measurements, so that the simulation model could be validated. We found that the degrader does not completely erase the initial beam phase space even at low degraded beam energies. Using the validation results, we present a study of the usability of beryllium as a degrader material (mean ionization potential 63.7 eV). We found an improvement in the transmission of 30-45%, depending on the degraded beam energy, the higher value for the lower energies. PMID:19741273

  9. Numerical simulation of polarization beam splitter with triangular lattice of multi-walled carbon nanotube arrays

    NASA Astrophysics Data System (ADS)

    Wu, Xingxing; Yun, Maojin; Wang, Mei; Liu, Chao; Li, Kai; Qin, Xiheng; Kong, Weijin; Dong, Lifeng

    2015-12-01

    A kind of polarization beam splitter with triangular lattice of multi-walled carbon nanotube arrays is designed and simulated. In the employed structure transverse-electric (TE) light is confined in the line defect with photonic band gap effect, while transverse-magnetic (TM) light is guided through it with extremely low diffraction. The performance of the designed polarization beam splitter is evaluated by utilizing optical properties of multi-walled carbon nanotubes, finite element modeling of wave propagation and transmission through periodic arrays. Simulation results indicate that the designed polarization beam splitter has low loss and less cross talk, and thereby may have practical applications in the integrated optical field.

  10. Light beam deflector performance: a comparative analysis.

    PubMed

    Zook, J D

    1974-04-01

    The performance of various types of analog light beam deflectors is summarized, and their relative positions in a deflector hierarchy are defined. The three types of deflectors considered are (1) mechanical (galvanometer) mirror deflectors, (2) acoustooptic deflectors, and (3) analog electrooptic deflectors. Material figures of merit are defined and compared, and the theoretical trade-off between speed and resolution is given for each type of deflector. PMID:20126095

  11. Focused Ion Beam Microscopy of ALH84001 Carbonate Disks

    NASA Technical Reports Server (NTRS)

    Thomas-Keprta, Kathie L.; Clemett, Simon J.; Bazylinski, Dennis A.; Kirschvink, Joseph L.; McKay, David S.; Vali, Hojatollah; Gibson, Everett K., Jr.; Romanek, Christopher S.

    2005-01-01

    Our aim is to understand the mechanism(s) of formation of carbonate assemblages in ALH84001. A prerequisite is that a detailed characterization of the chemical and physical properties of the carbonate be established. We present here analyses by transmission electron microscopy (TEM) of carbonate thin sections produced by both focused ion beam (FIB) sectioning and ultramicrotomy. Our results suggest that the formation of ALH84001 carbonate assemblages were produced by considerably more complex process(es) than simple aqueous precipitation followed by partial thermal decomposition as proposed by other investigators [e.g., 1-3].

  12. Carbon Beam Radio-Therapy and Research Activities at HIMAC

    NASA Astrophysics Data System (ADS)

    Kanazawa, Mitsutaka

    2007-05-01

    Radio-therapy with carbon ion beam has been carried out since 1994 at HIMAC (Heavy Ion Medical Accelerator in Chiba) in NIRS (National Institute of Radiological Sciences). Now, many types of tumors can be treated with carbon beam with excellent local controls of the tumors. Stimulated with good clinical results, requirement of the dedicated compact facility for carbon beam radio-therapy is increased. To realize this requirement, design study of the facility and the R&D's of the key components in this design are promoted by NIRS. According successful results of these activities, the dedicated compact facility will be realized in Gunma University. In this facility, the established irradiation method is expected to use, which is passive irradiation method with wobbler magnets and ridge filter. In this presentation, above R&D's will be presented together with clinical results and basic research activities at HIMAC.

  13. Operational Performance of LCLS Beam Instrumentation

    SciTech Connect

    Loos, Henrik; Akre, R.; Brachmann, A.; Coffee, R.; Decker, F.-J.; Ding, Y.; Dowell, D.; Edstrom, S.; Emma, P.; Fisher, A.; Frisch, J.; Gilevich, S.; Hays, G.; Hering, Ph.; Huang, Z.; Iverson, R.; Messerschmidt, M.; Miahnahri, A.; Moeller, S.; Nuhn, H.-D.; Ratner, D.; /SLAC /LLNL, Livermore

    2010-06-15

    The Linac Coherent Light Source (LCLS) X-ray FEL utilizing the last km of the SLAC linac has been operational since April 2009 and finished its first successful user run last December. The various diagnostics for electron beam properties including beam position monitors, wire scanners, beam profile monitors, and bunch length diagnostics are presented as well as diagnostics for the X-ray beam. The low emittance and ultra-short electron beam required for X-ray FEL operation has implications on the transverse and longitudinal diagnostics. The coherence effects of the beam profile monitors and the challenges of measuring fs long bunches are discussed.

  14. Radiative instability of electron beam in carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Batrakov, Konstantin G.; Kuzhir, Polina P.; Maksimenko, Sergey A.

    2006-08-01

    Basic mechanisms of the interaction of electron beam tavelling through a carbon nanotube with electromagnetic wave, resulting in the radiative instability and generation of stimulated radiation, are considered. The effect of the surface electromagnetic wave slow-down in CNT (c/v > 100) [Slepyan et al., Phys. Rev. B 60, 17136, 1999] is exploited to synchronize the wave and the beam and thus to realize the Cherenkov radiation mechanism. Alternative mechanism of the electron beam instability is proposed based on the undulator emission arising due to the interband transitions of electrons moving in nanotube. The dispersion equations of the electron beam instability and threshold conditions for the stimulated radiation are derived and studied. The analysis of the threshold conditions estimates the possibility of the stimulated emission by electron beam as realistic and attainable at present-day experimental technique.

  15. FIDDLING CARBON STRINGS WITH POLARIZED PROTON BEAMS.

    SciTech Connect

    HUANG, H.; KURITA, K.

    2006-05-01

    An innovative polarimeter based on proton carbon elastic scattering in the Coulomb Nuclear Interference (CNI) region was first tested in the Brookhaven AGS successfully. CNI Polarimeters were then installed in the AGS and both RHIC rings. The polarimeter consists of ultra-thin carbon targets and silicon strip detectors. The waveform digitizers are used for signal readout, which allows deadtime-less data processing on the fly. Polarimeters are crucial instrumentation for the RHIC spin physics program. This paper summarizes the polarimeter design issues and operation results.

  16. Bulk Cutting of Carbon Nanotubes Using Electron Beam Irradiation

    NASA Technical Reports Server (NTRS)

    Ziegler, Kirk J. (Inventor); Rauwald, Urs (Inventor); Hauge, Robert H. (Inventor); Schmidt, Howard K. (Inventor); Smalley, Richard E. (Inventor); Kittrell, W. Carter (Inventor); Gu, Zhenning (Inventor)

    2013-01-01

    According to some embodiments, the present invention provides a method for attaining short carbon nanotubes utilizing electron beam irradiation, for example, of a carbon nanotube sample. The sample may be pretreated, for example by oxonation. The pretreatment may introduce defects to the sidewalls of the nanotubes. The method is shown to produces nanotubes with a distribution of lengths, with the majority of lengths shorter than 100 tun. Further, the median length of the nanotubes is between about 20 nm and about 100 nm.

  17. A family of carbon-based nanocomposite tubular structures created by in situ electron beam irradiation.

    PubMed

    Liu, Jian-Wei; Xu, Jie; Ni, Yong; Fan, Feng-Jia; Zhang, Chuan-Ling; Yu, Shu-Hong

    2012-05-22

    We report a unique approach for the fabrication of a family of curling tubular nanostructures rapidly created by a rolling up of carbon membranes under in situ TEM electron beam irradiation. Multiwall tubes can also be created if irradiation by electron beam is performed long enough. This general approach can be extended to curve the conductive carbon film loaded with various functional nanomaterials, such as nanocrystals, nanorods, nanowires, and nanosheets, providing a unique strategy to make composite tubular structures and composite materials by a combination of desired optical, electronic, and magnetic properties, which could find potential applications, including fluid transportation, encapsulation, and capillarity on the nanometer scale. PMID:22530775

  18. Hadron Cancer Therapy - relative merits of X-ray, proton and carbon beams

    NASA Astrophysics Data System (ADS)

    Jakel, Oliver

    2014-03-01

    -Heidelberg University has a long experience in radiotherapy with carbon ions, starting with a pilot project at GSI in 1997. This project was jointly run by the Dep. for Radiation Oncology of Heidelberg University, GSI and the German Cancer Research Center (DKFZ). A hospital based heavy ion center at Heidelberg University, the Heidelberg Ion Beam Therapy Center (HIT) was proposed by the same group in 1998 and started clinical operation in late 2009. Since then nearly 2000 patients were treated with beams of carbon ions and protons. Just recently the operation of the world's first and only gantry for heavy ions also started at HIT. Patient treatments are performed in three rooms. Besides that, a lot of research projects are run in the field of Medical Physics and Radiobiology using a dedicated experimental area and the possibility to use beams of protons, carbon, helium and oxygen ions being delivered with the raster scanning technique.

  19. Ion beam and plasma methods of producing diamondlike carbon films

    NASA Technical Reports Server (NTRS)

    Swec, Diane M.; Mirtich, Michael J.; Banks, Bruce A.

    1988-01-01

    A variety of plasma and ion beam techniques was employed to generate diamondlike carbon films. These methods included the use of RF sputtering, dc glow discharge, vacuum arc, plasma gun, ion beam sputtering, and both single and dual ion beam deposition. Since films were generated using a wide variety of techniques, the physico-chemical properties of these films varied considerably. In general, these films had characteristics that were desirable in a number of applications. For example, the films generated using both single and dual ion beam systems were evaluated for applications including power electronics as insulated gates and protective coatings on transmitting windows. These films were impervious to reagents which dissolve graphitic and polymeric carbon structures. Nuclear reaction and combustion analysis indicated hydrogen to carbon ratios to be 1.00, which allowed the films to have good transmittance not only in the infrared, but also in the visible. Other evaluated properties of these films include band gap, resistivity, adherence, density, microhardness, and intrinsic stress. The results of these studies and those of the other techniques for depositing diamondlike carbon films are presented.

  20. Carbon-nanotube electron-beam (C-beam) crystallization technique for silicon TFTs

    NASA Astrophysics Data System (ADS)

    Lee, Su Woong; Kang, Jung Su; Park, Kyu Chang

    2016-02-01

    We introduced a carbon-nanotube (CNT) electron beam (C-beam) for thin film crystallization and thin film transistor (TFT) applications. As a source of electron emission, a CNT emitter which had been grown on a silicon wafer with a resist-assisted patterning (RAP) process was used. By using the C-beam exposure, we successfully crystallized a silicon thin film that had nano-sized crystalline grains. The distribution of crystalline grain size was about 10 ˜ 30 nm. This nanocrystalline silicon thin film definitely had three crystalline directions which are (111), (220) and (311), respectively. The silicon TFTs crystallized by using a C-beam exposure showed a field effect mobility of 20 cm2/Vs and an on/off ratio of more than 107. The C-beam exposure can modify the bonding network of amorphous silicon with its proper energy.

  1. High performance carbon nanocomposites for ultracapacitors

    DOEpatents

    Lu, Wen

    2012-10-02

    The present invention relates to composite electrodes for electrochemical devices, particularly to carbon nanotube composite electrodes for high performance electrochemical devices, such as ultracapacitors.

  2. Coherent beam combining performance in harsh environment

    NASA Astrophysics Data System (ADS)

    Lombard, L.; Canat, G.; Durecu, A.; Bourdon, P.

    2014-03-01

    Coherent beam combining (CBC) is a promising solution for high power directed energy weapons. We investigate several particular issues for this application: First, we study the evolution of phase noise spectrum for increasing pump power in 100 W MOPFA. The main variations in the spectrum are located in the low frequency region corresponding to thermal transfer between the fiber core heated by the pump absorption and the fiber environment. The phase noise root mean square evolves linearly with the pump power. Noise spectrum is not shifted to higher frequencies. Second, we investigate the influence of fiber packaging and amplifier packaging on the phase noise and estimate the LOCSET controller bandwidth (BW) requirement in each case. Results show large variation of BW depending on the packaging, and not on the power. Then, we investigate the performances of CBC in harsh environment. For this purpose, we implement CBC of a 20-W fiber amplifier and a passive fiber using the LOCSET technique and simulate harsh environment by applying strong vibrations with a hammering drill on the optical table. The applied vibration spectrum ranges from 1 Hz to ~10 kHz with a standard deviation of 9 m/s2. CBC of the amplifier output and the passive fiber output is performed on a second table, isolated from vibrations. Measurements of the phase difference between both outputs and of the applied vibrations are simultaneously performed. Residual phase error of λ/40 (i.e. > 99 % CBC efficiency) is achieved under strong vibrations at 20 W. The -3 dB bandwidth of the LOCSET controller has been measured to be ~4.5 kHz. Results are in agreement with simulations.

  3. Electron Cloud in Steel Beam Pipe vs Titanium Nitride Coated and Amorphous Carbon Coated Beam Pipes in Fermilab's Main Injector

    SciTech Connect

    Backfish, Michael

    2013-04-01

    This paper documents the use of four retarding field analyzers (RFAs) to measure electron cloud signals created in Fermilab’s Main Injector during 120 GeV operations. The first data set was taken from September 11, 2009 to July 4, 2010. This data set is used to compare two different types of beam pipe that were installed in the accelerator. Two RFAs were installed in a normal steel beam pipe like the rest of the Main Injector while another two were installed in a one meter section of beam pipe that was coated on the inside with titanium nitride (TiN). A second data run started on August 23, 2010 and ended on January 10, 2011 when Main Injector beam intensities were reduced thus eliminating the electron cloud. This second run uses the same RFA setup but the TiN coated beam pipe was replaced by a one meter section coated with amorphous carbon (aC). This section of beam pipe was provided by CERN in an effort to better understand how an aC coating will perform over time in an accelerator. The research consists of three basic parts: (a) continuously monitoring the conditioning of the three different types of beam pipe over both time and absorbed electrons (b) measurement of the characteristics of the surrounding magnetic fields in the Main Injector in order to better relate actual data observed in the Main Injector with that of simulations (c) measurement of the energy spectrum of the electron cloud signals using retarding field analyzers in all three types of beam pipe.

  4. Reinforcing multiwall carbon nanotubes by electron beam irradiation

    SciTech Connect

    Duchamp, Martial; Meunier, Richard; Smajda, Rita; Mionic, Marijana; Forro, Laszlo; Magrez, Arnaud; Seo, Jin Won; Song, Bo; Tomanek, David

    2010-10-15

    We study the effect of electron beam irradiation on the bending modulus of multiwall carbon nanotubes grown by chemical vapor deposition. Atomic force microscopy observations of the nanotube deflection in the suspended-beam geometry suggest an internal, reversible stick-slip motion prior to irradiation, indicating presence of extended defects. Upon electron beam irradiation, nanotubes with an initial bending modulus exceeding 10 GPa initially get stiffer, before softening at high doses. Highly defective nanotubes with smaller initial bending moduli do not exhibit the initial reinforcement. These data are explained by ab initio molecular dynamics calculations suggesting a spontaneous cross-linking of neighboring nanotube walls at extended vacancy defects created by the electron beam, in agreement with electron microscopy observations. At low defect concentration, depending on the edge morphology, the covalent bonds between neighboring nanotube walls cause reinforcement by resisting relative motion of neighboring walls. At high concentration of defects that are present initially or induced by high electron beam dose, the structural integrity of the entire system suffers from increasing electron beam damage.

  5. Beam-induced graphitic carbon cage transformation from sumanene aggregates

    SciTech Connect

    Fujita, Jun-ichi Tachi, Masashi; Murakami, Katsuhisa; Sakurai, Hidehiro; Morita, Yuki; Higashibayashi, Shuhei; Takeguchi, Masaki

    2014-01-27

    We found that electron-beam irradiation of sumanene aggregates strongly enhanced their transformation into a graphitic carbon cage, having a diameter of about 20 nm. The threshold electron dose was about 32 mC/cm{sup 2} at 200 keV, but the transformation is still induced at 20 keV. The transformation sequence suggested that the cage was constructed accompanied by the dynamical movement of the transiently linked sumanene molecules in order to pile up inside the shell. Thus, bond excitation in the sumanene molecules rather than a knock-on of carbon atoms seems to be the main cause of the cage transformation.

  6. Dosimetric characterization of a microDiamond detector in clinical scanned carbon ion beams

    SciTech Connect

    Marinelli, Marco; Prestopino, G. Verona, C.; Verona-Rinati, G.; Ciocca, M.; Mirandola, A.; Mairani, A.; Raffaele, L.; Magro, G.

    2015-04-15

    direction. A strong distortion in Bragg peak measurement was observed, confirming manufacturer recommendation on avoiding such configuration. Very good results were obtained for SOBP measurements, with a difference below 1% between measured and TPS-calculated doses. The stability of detector sensitivity in the observation period was within the experimental uncertainty. Conclusions: Dosimetric characterization of a PTW microDiamond detector in high-energy scanned carbon ion beams was performed. The results of the present study showed that this detector is suitable for dosimetry of clinical carbon ion beams, with a negligible LET and dose-rate dependence.

  7. Antares beam-alignment-system performance

    SciTech Connect

    Appert, Q.D.; Bender, S.C.

    1983-01-01

    The beam alignment system for the 24-beam-sector Antares CO/sub 2/ fusion laser automatically aligns more than 200 optical elements. A visible-wavelength alignment technique is employed which uses a telescope/TV system to view point-light sources appropriately located down the beamline. The centroids of the light spots are determined by a video tracker, which generates error signals used by the computer control system to move appropriate mirrors in a closed-loop system. Final touch-up alignment is accomplished by projecting a CO/sub 2/ alignment laser beam through the system and sensing its position at the target location. The techniques and control algorithms employed have resulted in alignment accuracies exceeding design requirements. By employing video processing to determine the centroids of diffraction images and by averaging over multiple TV frames, we achieve alignment accuracies better than 0.1 times system diffraction limits in the presence of air turbulence.

  8. Carbon-Ion Beam Irradiation Effectively Suppresses Migration and Invasion of Human Non-Small-Cell Lung Cancer Cells

    SciTech Connect

    Akino, Yuichi; Teshima, Teruki Kihara, Ayaka; Kodera-Suzumoto, Yuko; Inaoka, Miho; Higashiyama, Shigeki; Furusawa, Yoshiya; Matsuura, Nariaki

    2009-10-01

    Purpose: Control of cancer metastasis is one of the most important issues in cancer treatment. We previously demonstrated that carbon particle irradiation suppresses the metastatic potential of cancer cells, and many studies have reported that photon irradiation promotes it. The purpose of this study was to investigate the effect of carbon beam on non-small-cell lung cancer (NSCLC) cell aggressiveness and gene expression. Methods and Materials: A549 (lung adenocarcinoma) and EBC-1 (lung squamous cell carcinoma) cells were treated with 290 MeV/nucleon carbon ion beam at the Heavy Ion Medical Accelerator in Chiba or with 4-MV X-ray at Osaka University. We tested proliferative, migratory, and invasive activities by cell proliferation assay, Boyden chamber assay, and Matrigel chemoinvasion assay, respectively. cDNA microarray and reverse transcription polymerase chain reaction were also performed to assess mRNA expression alteration. Results: X-irradiation increased cell proliferation of A549 cells at 0.5 Gy, whereas high-dose X-ray reduced migration and invasion of A549 cells. By contrast, carbon beam irradiation did not enhance proliferation, and it reduced the migration and invasion capabilities of both A549 and EBC-1 cells more effectively than did X-irradiation. Carbon beam irradiation induced alteration of various gene expression profiles differently from X-ray irradiation. mRNA expression of ANLN, a homologue of anillin, was suppressed to 60% levels of basal expression in carbon beam-irradiated A549 cells after 12 h. Conclusion: Carbon beam effectively suppresses the metastatic potential of A549 and EBC-1 cells. Carbon beam also has different effects on gene expressions, and downregulation of ANLN was induced only by carbon beam irradiation.

  9. Microdosimetry for a carbon ion beam using track-etched detectors.

    PubMed

    Ambrožová, I; Vondráček, V; Šefl, M; Štěpán, V; Pachnerová Brabcová, K; Ploc, O; Incerti, S; Davídková, M

    2015-09-01

    Track-etched detectors (TED) have been used as linear energy transfer (LET) spectrometers in heavy ion beams for many years. LET spectra and depth-dose distribution of a carbon ion beam were measured behind polymethylmethacrylate degraders at Heavy Ion Medical Accelerator in Chiba, Japan. The measurements were performed along monoenergetic beam with energy 290 MeV u(-1) in different positions: (1) at beam extraction area, (2) at beginning, (3) maximum and (4) behind the Bragg peak region (0, 117, 147 and 151 mm of water-equivalent depth, respectively). The LET spectra inside and outside of the primary ion beam have been evaluated. TED record only heavy charged particles with LET above 8-10 keV µm(-1), while electrons and ions with lower LET are not detected. The Geant4 simulation toolkit version 4.9.6.P01 has been used to estimate the contribution of non-detected particles to absorbed dose. Presented results demonstrate the applicability of TED for microdosimetry measurements in therapeutic carbon ion beams. PMID:25862534

  10. Performance and Controllability of Pulsed Ion Beam Ablation Propulsion

    SciTech Connect

    Yazawa, Masaru; Buttapeng, Chainarong; Harada, Nobuhiro; Suematsu, Hisayuki; Jiang Weihua; Yatsui, Kiyoshi

    2006-05-02

    We propose novel propulsion driven by ablation plasma pressures produced by the irradiation of pulsed ion beams onto a propellant. The ion beam ablation propulsion demonstrates by a thin foil (50 {mu}mt), and the flyer velocity of 7.7 km/s at the ion beam energy density of 2 kJ/cm2 adopted by using the Time-of-flight method is observed numerically and experimentally. We estimate the performance of the ion beam ablation propulsion as specific impulse of 3600 s and impulse bit density of 1700 Ns/m2 obtained from the demonstration results. In the numerical analysis, a one-dimensional hydrodynamic model with ion beam energy depositions is used. The control of the ion beam kinetic energy is only improvement of the performance but also propellant consumption. The spacecraft driven by the ion beam ablation provides high performance efficiency with short-pulsed ion beam irradiation. The numerical results of the advanced model explained latent heat and real gas equation of state agreed well with experimental ones over a wide range of the incident ion beam energy density.

  11. Charge equilibrium of a laser-generated carbon-ion beam in warm dense matter.

    PubMed

    Gauthier, M; Chen, S N; Levy, A; Audebert, P; Blancard, C; Ceccotti, T; Cerchez, M; Doria, D; Floquet, V; Lamour, E; Peth, C; Romagnani, L; Rozet, J-P; Scheinder, M; Shepherd, R; Toncian, T; Vernhet, D; Willi, O; Borghesi, M; Faussurier, G; Fuchs, J

    2013-03-29

    Using ion carbon beams generated by high intensity short pulse lasers we perform measurements of single shot mean charge equilibration in cold or isochorically heated solid density aluminum matter. We demonstrate that plasma effects in such matter heated up to 1 eV do not significantly impact the equilibration of carbon ions with energies 0.045-0.5  MeV/nucleon. Furthermore, these measurements allow for a first evaluation of semiempirical formulas or ab initio models that are being used to predict the mean of the equilibrium charge state distribution for light ions passing through warm dense matter. PMID:23581330

  12. High-Performance Beam Simulator for the LANSCE Linac

    SciTech Connect

    Pang, Xiaoying; Rybarcyk, Lawrence J.; Baily, Scott A.

    2012-05-14

    A high performance multiparticle tracking simulator is currently under development at Los Alamos. The heart of the simulator is based upon the beam dynamics simulation algorithms of the PARMILA code, but implemented in C++ on Graphics Processing Unit (GPU) hardware using NVIDIA's CUDA platform. Linac operating set points are provided to the simulator via the EPICS control system so that changes of the real time linac parameters are tracked and the simulation results updated automatically. This simulator will provide valuable insight into the beam dynamics along a linac in pseudo real-time, especially where direct measurements of the beam properties do not exist. Details regarding the approach, benefits and performance are presented.

  13. Molecular sputter depth profiling using carbon cluster beams

    PubMed Central

    Winograd, Nicholas

    2010-01-01

    Sputter depth profiling of organic films while maintaining the molecular integrity of the sample has long been deemed impossible because of the accumulation of ion bombardment-induced chemical damage. Only recently, it was found that this problem can be greatly reduced if cluster ion beams are used for sputter erosion. For organic samples, carbon cluster ions appear to be particularly well suited for such a task. Analysis of available data reveals that a projectile appears to be more effective as the number of carbon atoms in the cluster is increased, leaving fullerene ions as the most promising candidates to date. Using a commercially available, highly focused C60q+ cluster ion beam, we demonstrate the versatility of the technique for depth profiling various organic films deposited on a silicon substrate and elucidate the dependence of the results on properties such as projectile ion impact energy and angle, and sample temperature. Moreover, examples are shown where the technique is applied to organic multilayer structures in order to investigate the depth resolution across film-film interfaces. These model experiments allow collection of valuable information on how cluster impact molecular depth profiling works and how to understand and optimize the depth resolution achieved using this technique. PMID:19649771

  14. Dual ion beam deposition of carbon films with diamondlike properties

    NASA Technical Reports Server (NTRS)

    Mirtich, M. J.; Swec, D. M.; Angus, J. C.

    1984-01-01

    A single and dual ion beam system was used to generate amorphous carbon films with diamond like properties. A methane/argon mixture at a molar ratio of 0.28 was ionized in the low pressure discharge chamber of a 30-cm-diameter ion source. A second ion source, 8 cm in diameter was used to direct a beam of 600 eV Argon ions on the substrates (fused silica or silicon) while the deposition from the 30-cm ion source was taking place. Nuclear reaction and combustion analysis indicate H/C ratios for the films to be 1.00. This high value of H/C, it is felt, allowed the films to have good transmittance. The films were impervious to reagents which dissolve graphitic and polymeric carbon structures. Although the measured density of the films was approximately 1.8 gm/cu cm, a value lower than diamond, the films exhibited other properties that were relatively close to diamond. These films were compared with diamondlike films generated by sputtering a graphite target.

  15. High performance pitch-based carbon fiber

    SciTech Connect

    Tadokoro, Hiroyuki; Tsuji, Nobuyuki; Shibata, Hirotaka; Furuyama, Masatoshi

    1996-12-31

    The high performance pitch-based carbon fiber with smaller diameter, six micro in developed by Nippon Graphite Fiber Corporation. This fiber possesses high tensile modulus, high tensile strength, excellent yarn handle ability, low thermal expansion coefficient, and high thermal conductivity which make it an ideal material for space applications such as artificial satellites. Performance of this fiber as a reinforcement of composites was sufficient. With these characteristics, this pitch-based carbon fiber is expected to find wide variety of possible applications in space structures, industrial field, sporting goods and civil infrastructures.

  16. Non-invasive monitoring of therapeutic carbon ion beams in a homogeneous phantom by tracking of secondary ions.

    PubMed

    Gwosch, K; Hartmann, B; Jakubek, J; Granja, C; Soukup, P; Jäkel, O; Martišíková, M

    2013-06-01

    Radiotherapy with narrow scanned carbon ion beams enables a highly accurate treatment of tumours while sparing the surrounding healthy tissue. Changes in the patient's geometry can alter the actual ion range in tissue and result in unfavourable changes in the dose distribution. Consequently, it is desired to verify the actual beam delivery within the patient. Real-time and non-invasive measurement methods are preferable. Currently, the only technically feasible method to monitor the delivered dose distribution within the patient is based on tissue activation measurements by means of positron emission tomography (PET). An alternative monitoring method based on tracking of prompt secondary ions leaving a patient irradiated with carbon ion beams has been previously suggested. It is expected to help in overcoming the limitations of the PET-based technique like physiological washout of the beam induced activity, low signal and to allow for real-time measurements. In this paper, measurements of secondary charged particle tracks around a head-sized homogeneous PMMA phantom irradiated with pencil-like carbon ion beams are presented. The investigated energies and beam widths are within the therapeutically used range. The aim of the study is to deduce properties of the primary beam from the distribution of the secondary charged particles. Experiments were performed at the Heidelberg Ion Beam Therapy Center, Germany. The directions of secondary charged particles emerging from the PMMA phantom were measured using an arrangement of two parallel pixelated silicon detectors (Timepix). The distribution of the registered particle tracks was analysed to deduce its dependence on clinically important beam parameters: beam range, width and position. Distinct dependencies of the secondary particle tracks on the properties of the primary carbon ion beam were observed. In the particular experimental set-up used, beam range differences of 1.3 mm were detectable. In addition, variations in

  17. Dosimetric characterization of the iBEAM evo carbon fiber couch for radiotherapy

    SciTech Connect

    Smith, David W.; Christophides, Damianos; Dean, Christopher; Naisbit, Mitchell; Mason, Joshua; Morgan, Andrew

    2010-07-15

    Purpose: This study characterizes the dosimetric properties of the iBEAM evo carbon fiber couch manufactured by Medical Intelligence and examines the accuracy of the CMS XiO and Nucletron Oncentra Masterplan (OMP) treatment planning systems for calculating beam attenuation due to the presence of the couch. Methods: To assess the homogeneity of the couch, it was CT scanned at isocentric height and a number of signal intensity profiles were generated and analyzed. To simplify experimental procedures, surface dose and central axis depth dose measurements were performed in a solid water slab phantom using Gafchromic film for 6 and 10 MV photon beams at gantry angles of 0 deg. (normal incidence), 30 deg., and 60 deg. with an inverted iBEAM couch placed on top of the phantom. Attenuation measurements were performed in a cylindrical solid water phantom with an ionization chamber positioned at the isocenter. Measurements were taken for gantry angles from 0 deg. to 90 deg. in 10 deg. increments for both 6 and 10 MV photon beams. This setup was replicated in the XiO and OMP treatment planning systems. Dose was calculated using the pencil beam, collapsed cone, convolution, and superposition algorithms. Results: The CT scan of the couch showed that it was uniformly constructed. Surface dose increased by (510{+-}30)% for a 6 MV beam and (600{+-}20)% for a 10 MV beam passing through the couch at normal incidence. Obliquely incident beams resulted in a higher surface dose compared to normally incident beams for both open fields and fields with the couch present. Depth dose curves showed that the presence of the couch resulted in an increase in dose in the build up region. For 6 and 10 MV beams incident at 60 deg., nearly all skin sparing was lost. Attenuation measurements derived using the ionization chamber varied from 2.7% (0 deg.) to a maximum of 4.6% (50 deg.) for a 6 MV beam and from 1.9% (0 deg.) to a maximum of 4.0% (50 deg.) for a 10 MV beam. The pencil beam and

  18. Resolution of a High Performance Cavity Beam Position Monitor System

    SciTech Connect

    Walston, S; Chung, C; Fitsos, P; Gronberg, J; Ross, M; Khainovski, O; Kolomensky, Y; Loscutoff, P; Slater, M; Thomson, M; Ward, D; Boogert, S; Vogel, V; Meller, R; Lyapin, A; Malton, S; Miller, D; Frisch, J; Hinton, S; May, J; McCormick, D; Smith, S; Smith, T; White, G; Orimoto, T; Hayano, H; Honda, Y; Terunuma, N; Urakawa, J

    2005-09-12

    International Linear Collider (ILC) interaction region beam sizes and component position stability requirements will be as small as a few nanometers. It is important to the ILC design effort to demonstrate that these tolerances can be achieved - ideally using beam-based stability measurements. It has been estimated that RF cavity beam position monitors (BPMs) could provide position measurement resolutions of less than one nanometer and could form the basis of the desired beam-based stability measurement. We have developed a high resolution RF cavity BPM system. A triplet of these BPMs has been installed in the extraction line of the KEK Accelerator Test Facility (ATF) for testing with its ultra-low emittance beam. A metrology system for the three BPMs was recently installed. This system employed optical encoders to measure each BPM's position and orientation relative to a zero-coefficient of thermal expansion carbon fiber frame and has demonstrated that the three BPMs behave as a rigid-body to less than 5 nm. To date, we have demonstrated a BPM resolution of less than 20 nm over a dynamic range of +/- 20 microns.

  19. Resolution of a High Performance Cavity Beam Positron Monitor System

    SciTech Connect

    Walston, S.; Chung, C.; Fitsos, P.; Gronberg, J.; Ross, M.; Khainovski, O.; Kolomensky, Y.; Loscutoff, P.; Slater, M.; Thomson, M.; Ward, D.; Boogert, S.; Vogel, V.; Meller, R.; Lyapin, A.; Malton, S.; Miller, D.; Frisch, J.; Hinton, S.; May, J.; McCormick, D.; /SLAC /Caltech /KEK, Tsukuba

    2007-07-06

    International Linear Collider (ILC) interaction region beam sizes and component position stability requirements will be as small as a few nanometers. It is important to the ILC design effort to demonstrate that these tolerances can be achieved--ideally using beam-based stability measurements. It has been estimated that RF cavity beam position monitors (BPMs) could provide position measurement resolutions of less than one nanometer and could form the basis of the desired beam-based stability measurement. We have developed a high resolution RF cavity BPM system. A triplet of these BPMs has been installed in the extraction line of the KEK Accelerator Test Facility (ATF) for testing with its ultra-low emittance beam. A metrology system for the three BPMs was recently installed. This system employed optical encoders to measure each BPM's position and orientation relative to a zero-coefficient of thermal expansion carbon fiber frame and has demonstrated that the three BPMs behave as a rigid-body to less than 5 nm. To date, we have demonstrated a BPM resolution of less than 20 nm over a dynamic range of +/- 20 microns.

  20. Performance predictions of a focused ion beam from a laser cooled and compressed atomic beam

    SciTech Connect

    Haaf, G. ten; Wouters, S. H. W.; Vredenbregt, E. J. D.; Mutsaers, P. H. A.; Geer, S. B. van der

    2014-12-28

    Focused ion beams are indispensable tools in the semiconductor industry because of their ability to image and modify structures at the nanometer length scale. Here, we report on performance predictions of a new type of focused ion beam based on photo-ionization of a laser cooled and compressed atomic beam. Particle tracing simulations are performed to investigate the effects of disorder-induced heating after ionization in a large electric field. They lead to a constraint on this electric field strength which is used as input for an analytical model which predicts the minimum attainable spot size as a function of, amongst others, the flux density of the atomic beam, the temperature of this beam, and the total current. At low currents (I < 10 pA), the spot size will be limited by a combination of spherical aberration and brightness, while at higher currents, this is a combination of chromatic aberration and brightness. It is expected that a nanometer size spot is possible at a current of 1 pA. The analytical model was verified with particle tracing simulations of a complete focused ion beam setup. A genetic algorithm was used to find the optimum acceleration electric field as a function of the current. At low currents, the result agrees well with the analytical model, while at higher currents, the spot sizes found are even lower due to effects that are not taken into account in the analytical model.

  1. Enhanced piezoelectric performance from carbon fluoropolymer nanocomposites

    NASA Astrophysics Data System (ADS)

    Baur, Cary; DiMaio, Jeffrey R.; McAllister, Elliot; Hossini, Reza; Wagener, Earl; Ballato, John; Priya, Shashank; Ballato, Arthur; Smith, Dennis W.

    2012-12-01

    The piezoelectric performance of polyvinylidene fluoride (PVDF) is shown to double through the controlled incorporation of carbon nanomaterial. Specifically, PVDF composites containing carbon fullerenes (C60) and single-walled carbon nanotubes (SWNT) are fabricated over a range of compositions and optimized for their Young's modulus, dielectric constant, and d31 piezoelectric coefficient. Thermally stimulated current measurements show a large increase in internal charge and polarization in the composites over pure PVDF. The electromechanical coupling coefficients (k31) at optimal loading levels are found to be 1.84 and 2 times greater than pure PVDF for the PVDF-C60 and PVDF-SWNT composites, respectively. Such property-enhanced nanocomposites could have significant benefit to electromechanical systems employed for structural sensing, energy scavenging, sonar, and biomedical imaging.

  2. Electron beam-induced nanopatterning of multilayer graphene and amorphous carbon films with metal layers

    SciTech Connect

    Rodriguez-Manzo, Julio A.; Banhart, Florian

    2011-05-02

    Thin Co and Ni lamellae grow under electron irradiation of metal crystals supported on multilayer graphene or amorphous carbon films. The lateral growth of a lamella from a source crystal is achieved by directing an electron beam to the periphery of the metal crystal and moving the beam over the surrounding carbon. Patterns of linear, branched, or ringlike metal lamellae can be created. The patterning is carried out in situ in a transmission electron microscope, allowing simultaneous structuring and imaging. The process is driven by the metal-carbon interaction at a beam-activated carbon surface.

  3. Dissociation phenomena in electron-beam sustained carbon dioxide lasers

    NASA Technical Reports Server (NTRS)

    Harris, Michael R.; Willetts, David V.

    1990-01-01

    A number of applications are emerging requiring efficient, long pulse, long-life sealed CO2 lasers. Examples include the proposed NASA and ESA wind lidars. Electron-beam sustained discharge devices are strong contenders. Unlike self-sustained discharges, e-beam sustenance readily provides efficient performance from large volume discharges and offers pulse lengths well in excess of the microsecond or so generally associated with self-sustained devices. In the case of the e-beam sustained laser, since the plasma is externally maintained and operated at electric field strengths less than that associated with the glow to arc transition, the discharges can be run even in the presence of strongly attacking species such as O2. Build up of large levels of attacking contaminants is nevertheless undesirable as their presence reduces the current drawn by the plasma and thus the pumping rate to the upper laser level. The impedance rise leads to a mismatch of the pulse forming network with a consequent loss of control over energy deposition, operating E/N, and gain. Clearly CO2 dissociation rates, the influence of dissociation products on the discharge and gain, and tolerance of the discharge to these products need to be determined. This information can then be used to assess co-oxidation catalyst requirements for sealed operation.

  4. Dissociation phenomena in electron-beam sustained carbon dioxide lasers

    NASA Astrophysics Data System (ADS)

    Harris, Michael R.; Willetts, David V.

    1990-06-01

    A number of applications are emerging requiring efficient, long pulse, long-life sealed CO2 lasers. Examples include the proposed NASA and ESA wind lidars. Electron-beam sustained discharge devices are strong contenders. Unlike self-sustained discharges, e-beam sustenance readily provides efficient performance from large volume discharges and offers pulse lengths well in excess of the microsecond or so generally associated with self-sustained devices. In the case of the e-beam sustained laser, since the plasma is externally maintained and operated at electric field strengths less than that associated with the glow to arc transition, the discharges can be run even in the presence of strongly attacking species such as O2. Build up of large levels of attacking contaminants is nevertheless undesirable as their presence reduces the current drawn by the plasma and thus the pumping rate to the upper laser level. The impedance rise leads to a mismatch of the pulse forming network with a consequent loss of control over energy deposition, operating E/N, and gain. Clearly CO2 dissociation rates, the influence of dissociation products on the discharge and gain, and tolerance of the discharge to these products need to be determined. This information can then be used to assess co-oxidation catalyst requirements for sealed operation.

  5. Assessment of carbon layer growth induced by resists outgassing in multi e-beams lithography

    NASA Astrophysics Data System (ADS)

    Marusic, JC; Pourteau, ML; Cêtre, S.; Pain, L.; Mebiene-Engohang, AP; David, S.; Labau, S.; Boussey, J.

    2014-10-01

    The development of multiple e-beam lithography equipment is seen as an alternative for next generation lithography. However, similarly to EUV lithography, this technology faces important challenges in controlling the contamination of the optics due to deposition of carbon layer induced by the outgassed chemical species from resist under electron bombardment. An experimental setup was designed and built at LETI to study the outgassed species and observe the carbon layer. In this setup, resist coated wafers 100 mm size are exposed under a 5 kV e-beam gun. During exposure, byproducts from outgassed species are monitored with a Residual Gas Analyzer (RGA). The identification of outgassed chemical species is done with an ex-situ TD-GC-MS analysis (ThermoDesorption-Gaz Chromatography-Mass Spectrometry). In a second part of this investigation, we observed the contamination carbon layer growth induced by the outgassing. Thereby, we fabricated a device which consists of a silicon membrane with micro-machined apertures. During e-beam exposure, this device simulates the multiple parallel beams of the optic system of a maskless lithography tool. The deposited contamination layer on device is then observed and thickness measured under SEM. In this paper, we present the results of outgassing and contamination on 3 chemically amplified resists showing that contamination is not directly dependent of the overall outgassing rate but on first order of the outgassing from Photo Acid Generator (PAG). It also reports on the performance in reducing outgassing and contamination of applying a top-coat layer on top of the resist and shows that reduction is more important for contamination than for outgassing.

  6. Performance model of molten carbonate fuel cell

    SciTech Connect

    Matsumoto, S.; Sasaki, A.; Urushibata, H.; Tanaka, T. )

    1990-06-01

    A performance model of a molten carbonate fuel cell (MCFC), that is an electrochemical energy conversion device for electric power generation, is discussed. The authors' purpose is to improve the presumptive ability of the MCFC model and to investigate the impact of MCFC characteristics in fuel cell system simulations. Basic data are obtained experimentally by single-cell tests. The authors pay special attention to the MCFC overall characteristics with respect to oxidant composition. A correlation formula based on the experimental data is derived as for the cell voltage, oxygen and carbon dioxide partial pressures. After three types of the MCFC system option are assumed, trade-off studies are made dependant on the performance models.

  7. A trichrome beam model for biological dose calculation in scanned carbon-ion radiotherapy treatment planning

    NASA Astrophysics Data System (ADS)

    Inaniwa, T.; Kanematsu, N.

    2015-01-01

    In scanned carbon-ion (C-ion) radiotherapy, some primary C-ions undergo nuclear reactions before reaching the target and the resulting particles deliver doses to regions at a significant distance from the central axis of the beam. The effects of these particles on physical dose distribution are accounted for in treatment planning by representing the transverse profile of the scanned C-ion beam as the superposition of three Gaussian distributions. In the calculation of biological dose distribution, however, the radiation quality of the scanned C-ion beam has been assumed to be uniform over its cross-section, taking the average value over the plane at a given depth (monochrome model). Since these particles, which have relatively low radiation quality, spread widely compared to the primary C-ions, the radiation quality of the beam should vary with radial distance from the central beam axis. To represent its transverse distribution, we propose a trichrome beam model in which primary C-ions, heavy fragments with atomic number Z ≥ 3, and light fragments with Z ≤ 2 are assigned to the first, second, and third Gaussian components, respectively. Assuming a realistic beam-delivery system, we performed computer simulations using Geant4 Monte Carlo code for analytical beam modeling of the monochrome and trichrome models. The analytical beam models were integrated into a treatment planning system for scanned C-ion radiotherapy. A target volume of 20  ×  20  ×  40 mm3 was defined within a water phantom. A uniform biological dose of 2.65 Gy (RBE) was planned for the target with the two beam models based on the microdosimetric kinetic model (MKM). The plans were recalculated with Geant4, and the recalculated biological dose distributions were compared with the planned distributions. The mean target dose of the recalculated distribution with the monochrome model was 2.72 Gy (RBE), while the dose with the trichrome model was 2.64 Gy (RBE). The monochrome model

  8. Comparison of the TESLA, NLC and CLIC beam collimation performance

    SciTech Connect

    Alexandr I Drozhdin et al.

    2003-03-27

    This note describes studies performed in the framework of the Collimation Task Force organized to support the work of the International Linear Collider Technical Review Committee. The post-linac beam-collimation systems in the TESLA, JLC/NLC and CLIC linear-collider designs are compared using the same computer code under the same assumptions. Their performance is quantified in terms of beam-halo and synchrotron-radiation collimation efficiency. The performance of the current designs varies across projects, and does not always meet the original design goals. But these comparisons suggest that achieving the required performance in a future linear collider is feasible. The post-TRC plans of the Collimation Task Force are briefly outlined in closing.

  9. Test beam performance of CDF plug upgrade EM calorimeter

    SciTech Connect

    Fukui, Y.; CDF Upgrade Group

    1998-01-01

    CDF Plug Upgrade(tile-fiber) EM Calorimeter performed resolution of 15%/{radical}E{circle_plus}0.7% with non-linearity less than 1% in a energy range of 5-180 GeV at Fermilab Test Beam. Transverse uniformity of inside-tower-response of the EM Calorimeter was 2.2% with 56 GeV positron, which was reduced to 1.0% with response map correction. We observed 300 photo electron/GeV in the EM Calorimeter. Ratios of EM Calorimeter response to positron beam to that to {sup 137}Cs Source was stable within 1% in the period of 8 months.

  10. Dose-Response Effect of Charged Carbon Beam on Normal Rat Retina Assessed by Electroretinography

    SciTech Connect

    Mizota, Atsushi; Tanaka, Minoru; Kubota, Mariko; Negishi, Hisanari; Watanabe, Emiko; Tsuji, Hiroshi; Miyahara, Nobuyuki; Furusawa, Yoshiya

    2010-12-01

    Purpose: To compare the effects of carbon beam irradiation with those of proton beam irradiation on the physiology of the retina of rats. Methods and Materials: Eight-week-old Wister rats were used. The right eyes were irradiated with carbon beam (1, 2, 4, 8, and 16 Gy) or proton beam (4, 8, 16, and 24 Gy) with the rats under general anesthesia. Electroretinograms were recorded 1, 3, 6, and 12 months after the irradiation, and the amplitudes of the a and b waves were compared with those of control rats. Results: The amplitude of b waves was reduced more than that of a waves at lower irradiation doses with both types of irradiation. With carbon ion irradiation, the amplitudes of the b wave were significantly reduced after radiation doses of 8 and 16 Gy at 6 months and by radiation doses of 4, 8, and 16 Gy at 12 months. With proton beam irradiation, the b-wave amplitudes were significantly reduced after 16 and 24 Gy at 6 months and with doses of 8 Gy or greater at 12 months. For the maximum b-wave amplitude, a significant difference was observed in rats irradiated with carbon beams of 4 Gy or more and with proton beams of 8 Gy or more at 12 months after irradiation. Conclusions: These results indicate that carbon beam irradiation is about two times more damaging than proton beam irradiation on the rat retina at the same dose.

  11. Influence of electron beam halos on the FEL performance

    NASA Astrophysics Data System (ADS)

    Faatz, B.; Reiche, S.

    1999-06-01

    For single-pass free-electron lasers (FEL), such as amplifiers and SASE devices, saturation of the radiation power has to be reached within the length of the undulator. Therefore, detailed knowledge of electron beam parameters is crucial. So far, simulations have been performed with a given rms emittance and energy spread. At short radiation wavelengths, bunch compressors are used to compress the electron beam to achieve the desired high peak currents. In addition, external focusing along the entire undulator is used to maintain a constant small radius. The rotation of phase space due to compression might lead to a significant part of the bunch in tails that could increase the gain length. Furthermore, it is in general not possible to match both the beam core and the tail to the focusing structure. In this contribution, the influence of these tails, both transverse and in energy, on the FEL performance will be investigated. Simulations will be performed for beam parameters that have been assumed for the TESLA Test Facility FEL at DESY.

  12. Fast beam condition monitor for CMS: Performance and upgrade

    NASA Astrophysics Data System (ADS)

    Leonard, Jessica L.; Bell, Alan; Burtowy, Piotr; Dabrowski, Anne; Hempel, Maria; Henschel, Hans; Lange, Wolfgang; Lohmann, Wolfgang; Odell, Nathaniel; Penno, Marek; Pollack, Brian; Przyborowski, Dominik; Ryjov, Vladimir; Stickland, David; Walsh, Roberval; Warzycha, Weronika; Zagozdzinska, Agnieszka

    2014-11-01

    The CMS beam and radiation monitoring subsystem BCM1F (Fast Beam Condition Monitor) consists of 8 individual diamond sensors situated around the beam pipe within the pixel detector volume, for the purpose of fast bunch-by-bunch monitoring of beam background and collision products. In addition, effort is ongoing to use BCM1F as an online luminosity monitor. BCM1F will be running whenever there is beam in LHC, and its data acquisition is independent from the data acquisition of the CMS detector, hence it delivers luminosity even when CMS is not taking data. A report is given on the performance of BCM1F during LHC run I, including results of the van der Meer scan and on-line luminosity monitoring done in 2012. In order to match the requirements due to higher luminosity and 25 ns bunch spacing, several changes to the system must be implemented during the upcoming shutdown, including upgraded electronics and precise gain monitoring. First results from Run II preparation are shown.

  13. Analytical, Numerical and Experimental Examination of Reinforced Composites Beams Covered with Carbon Fiber Reinforced Plastic

    NASA Astrophysics Data System (ADS)

    Kasimzade, A. A.; Tuhta, S.

    2012-03-01

    In the article, analytical, numerical (Finite Element Method) and experimental investigation results of beam that was strengthened with fiber reinforced plastic-FRP composite has been given as comparative, the effect of FRP wrapping number to the maximum load and moment capacity has been evaluated depending on this results. Carbon FRP qualitative dependences have been occurred between wrapping number and beam load and moment capacity for repair-strengthen the reinforced concrete beams with carbon fiber. Shown possibilities of application traditional known analysis programs, for the analysis of Carbon Fiber Reinforced Plastic (CFRP) strengthened structures.

  14. Integration and evaluation of automated Monte Carlo simulations in the clinical practice of scanned proton and carbon ion beam therapy

    NASA Astrophysics Data System (ADS)

    Bauer, J.; Sommerer, F.; Mairani, A.; Unholtz, D.; Farook, R.; Handrack, J.; Frey, K.; Marcelos, T.; Tessonnier, T.; Ecker, S.; Ackermann, B.; Ellerbrock, M.; Debus, J.; Parodi, K.

    2014-08-01

    Monte Carlo (MC) simulations of beam interaction and transport in matter are increasingly considered as essential tools to support several aspects of radiation therapy. Despite the vast application of MC to photon therapy and scattered proton therapy, clinical experience in scanned ion beam therapy is still scarce. This is especially the case for ions heavier than protons, which pose additional issues like nuclear fragmentation and varying biological effectiveness. In this work, we present the evaluation of a dedicated framework which has been developed at the Heidelberg Ion Beam Therapy Center to provide automated FLUKA MC simulations of clinical patient treatments with scanned proton and carbon ion beams. Investigations on the number of transported primaries and the dimension of the geometry and scoring grids have been performed for a representative class of patient cases in order to provide recommendations on the simulation settings, showing that recommendations derived from the experience in proton therapy cannot be directly translated to the case of carbon ion beams. The MC results with the optimized settings have been compared to the calculations of the analytical treatment planning system (TPS), showing that regardless of the consistency of the two systems (in terms of beam model in water and range calculation in different materials) relevant differences can be found in dosimetric quantities and range, especially in the case of heterogeneous and deep seated treatment sites depending on the ion beam species and energies, homogeneity of the traversed tissue and size of the treated volume. The analysis of typical TPS speed-up approximations highlighted effects which deserve accurate treatment, in contrast to adequate beam model simplifications for scanned ion beam therapy. In terms of biological dose calculations, the investigation of the mixed field components in realistic anatomical situations confirmed the findings of previous groups so far reported only in

  15. Parellel beam dynamics calculations on high performance computers

    SciTech Connect

    Ryne, R.; Habib, S.

    1996-12-01

    Faced with a backlog of nuclear waste and weapons plutonium, as well as an ever-increasing public concern about safety and environmental issues associated with conventional nuclear reactors, many countries are studying new, accelerator-driven technologies that hold the promise of providing safe and effective solutions to these problems. Proposed projects include accelerator transmutation of waste (ATW), accelerator-based conversion of plutonium (ABC), accelerator-driven energy production (ADEP), and accelerator production of tritium (APT). Also, next-generation spallation neutron sources based on similar technology will play a major role in materials science and biological science research. The design of accelerators for these projects will require a major advance in numerical modeling capability. For example, beam dynamics simulations with approximately 100 million particles will be needed to ensure that extremely stringent beam loss requirements (less than a nanoampere per meter) can be met. Compared with typical present-day modeling using 10,000-100,000 particles, this represents an increase of 3-4 orders of magnitude. High performance computing (HPC) platforms make it possible to perform such large scale simulations, which require 10`s of GBytes of memory. They also make it possible to perform smaller simulations in a matter of hours that would require months to run on a single processor workstation. This paper will describe how HPC platforms can be used to perform the numerically intensive beam dynamics simulations required for development of these new accelerator-driven technologies.

  16. Parallel beam dynamics calculations on high performance computers

    NASA Astrophysics Data System (ADS)

    Ryne, Robert; Habib, Salman

    1997-02-01

    Faced with a backlog of nuclear waste and weapons plutonium, as well as an ever-increasing public concern about safety and environmental issues associated with conventional nuclear reactors, many countries are studying new, accelerator-driven technologies that hold the promise of providing safe and effective solutions to these problems. Proposed projects include accelerator transmutation of waste (ATW), accelerator-based conversion of plutonium (ABC), accelerator-driven energy production (ADEP), and accelerator production of tritium (APT). Also, next-generation spallation neutron sources based on similar technology will play a major role in materials science and biological science research. The design of accelerators for these projects will require a major advance in numerical modeling capability. For example, beam dynamics simulations with approximately 100 million particles will be needed to ensure that extremely stringent beam loss requirements (less than a nanoampere per meter) can be met. Compared with typical present-day modeling using 10,000-100,000 particles, this represents an increase of 3-4 orders of magnitude. High performance computing (HPC) platforms make it possible to perform such large scale simulations, which require 10's of GBytes of memory. They also make it possible to perform smaller simulations in a matter of hours that would require months to run on a single processor workstation. This paper will describe how HPC platforms can be used to perform the numerically intensive beam dynamics simulations required for development of these new accelerator-driven technologies.

  17. Performance of the KTeV high-energy neutral kaon beam at Fermilab

    SciTech Connect

    Bocean, V.

    1998-06-01

    The performance of the primary and secondary beams for the KTeV experiments E832 and E799-II is reviewed. The beam was commissioned in the summer of 1996 and initially operated for approximately one year. The report includes results on the primary beam, target station including primary beam dump and muon sweeping system, neutral beam collimation system, and alignment.

  18. Ion beam deposition of amorphous carbon films with diamond like properties

    NASA Technical Reports Server (NTRS)

    Angus, John C.; Mirtich, Michael J.; Wintucky, Edwin G.

    1982-01-01

    Carbon films were deposited on silicon, quartz, and potassium bromide substrates from an ion beam. Growth rates were approximately 0.3 micron/hour. The films were featureless and amorphous and contained only carbon and hydrogen in significant amounts. The density and carbon/hydrogen ratio indicate the film is a hydrogen deficient polymer. One possible structure, consistent with the data, is a random network of methylene linkages and tetrahedrally coordinated carbon atoms.

  19. Robust, easily shaped, and epoxy-free carbon-fiber-aluminum cathodes for generating high-current electron beams

    NASA Astrophysics Data System (ADS)

    Liu, Lie; Li, Limin; Wen, Jianchun; Wan, Hong

    2009-02-01

    This paper presents the construction of carbon-fiber-aluminum (CFA) cathode by squeezing casting and its applications for generating high-current electron beams to drive high-power microwave sources. The fabrication process avoided using epoxy, a volatile deteriorating the vacuum system. These cathodes had a higher hardness than conventional aluminum, facilitating machining. After surface treatment, carbon fibers became the dominator determining emission property. A multineedle CFA cathode was utilized in a triode virtual cathode oscillator (vircator), powered by a ˜450 kV, ˜400 ns pulse. It was found that 300-400 MW, ˜250 ns microwave was radiated at a dominant frequency of 2.6 GHz. Further, this cathode can endure high-current-density emission without detectable degradation in performance as the pulse shot proceeded, showing the robust nature of carbon fibers as explosive emitters. Overall, this new class of cold cathodes offers a potential prospect of developing high-current electron beam sources.

  20. Test beam performance of the CDF plug upgrade hadron calorimeter

    SciTech Connect

    de Barbaro, P.; CDF Plug Upgrade Group

    1998-01-13

    We report on the performance of the CDF End Plug Hadron Calorimeter in a test beam. The sampling calorimeter is constructed using 2 inch iron absorber plates and scintillator planes with wavelength shifting fibers for readout. The linearity and energy resolution of the calorimeter response to pions, and the transverse uniformity of the response to muons and pions are presented. The parameter e/h, representing the ratio of the electromagnetic to hadronic response, is extracted from the data.

  1. Performance of a reentrant cavity beam position monitor

    NASA Astrophysics Data System (ADS)

    Simon, Claire; Luong, Michel; Chel, Stéphane; Napoly, Olivier; Novo, Jorge; Roudier, Dominique; Rouvière, Nelly; Baboi, Nicoleta; Mildner, Nils; Nölle, Dirk

    2008-08-01

    The beam-based alignment and feedback systems, essential operations for the future colliders, require high resolution beam position monitors (BPMs). In the framework of the European CARE/SRF program, a reentrant cavity BPM with its associated electronics was developed by the CEA/DSM/Irfu in collaboration with DESY. The design, the fabrication, and the beam test of this monitor are detailed within this paper. This BPM is designed to be inserted in a cryomodule, work at cryogenic temperature in a clean environment. It has achieved a resolution better than 10μm and has the possibility to perform bunch to bunch measurements for the x-ray free electron laser (X-FEL) and the International Linear Collider (ILC). Its other features are a small size of the rf cavity, a large aperture (78 mm), and an excellent linearity. A first prototype of a reentrant cavity BPM was installed in the free electron laser in Hamburg (FLASH), at Deutsches Elektronen-Synchrotron (DESY) and demonstrated its operation at cryogenic temperature inside a cryomodule. The second, installed, also, in the FLASH linac to be tested with beam, measured a resolution of approximately 4μm over a dynamic range ±5mm in single bunch.

  2. Physical and engineering aspect of carbon beam therapy

    NASA Astrophysics Data System (ADS)

    Kanai, Tatsuaki; Kanematsu, Nobuyuki; Minohara, Shinichi; Yusa, Ken; Urakabe, Eriko; Mizuno, Hideyuki; Iseki, Yasushi; Kanazawa, Mitsutaka; Kitagawa, Atsushi; Tomitani, Takehiro

    2003-08-01

    Conformal irradiation system of HIMAC has been up-graded for a clinical trial using a technique of a layer-stacking method. The system has been developed for localizing irradiation dose to target volume more effectively than the present irradiation dose. With dynamic control of the beam modifying devices, a pair of wobbler magnets, and multileaf collimator and range shifter, during the irradiation, more conformal radiotherapy can be achieved. The system, which has to be adequately safe for patient irradiations, was constructed and tested from a viewpoint of safety and the quality of the dose localization realized. A secondary beam line has been constructed for use of radioactive beam in heavy-ion radiotherapy. Spot scanning method has been adapted for the beam delivery system of the radioactive beam. Dose distributions of the spot beam were measured and analyzed taking into account of aberration of the beam optics. Distributions of the stopped positron-emitter beam can be observed by PET. Pencil beam of the positron-emitter, about 1 mm size, can also be used for measurements ranges of the test beam in patients using positron camera. The positron camera, consisting of a pair of Anger-type scintillation detectors, has been developed for this verification before treatment. Wash-out effect of the positron-emitter was examined using the positron camera installed. In this report, present status of the HIMAC irradiation system is described in detail.

  3. Physical and engineering aspect of carbon beam therapy

    SciTech Connect

    Kanai, Tatsuaki; Kanematsu, Nobuyuki; Minohara, Shinichi; Yusa, Ken; Urakabe, Eriko; Kanazawa, Mitsutaka; Kitagawa, Atsushi; Tomitani, Takehiro; Mizuno, Hideyuki; Iseki, Yasushi

    2003-08-26

    Conformal irradiation system of HIMAC has been up-graded for a clinical trial using a technique of a layer-stacking method. The system has been developed for localizing irradiation dose to target volume more effectively than the present irradiation dose. With dynamic control of the beam modifying devices, a pair of wobbler magnets, and multileaf collimator and range shifter, during the irradiation, more conformal radiotherapy can be achieved. The system, which has to be adequately safe for patient irradiations, was constructed and tested from a viewpoint of safety and the quality of the dose localization realized. A secondary beam line has been constructed for use of radioactive beam in heavy-ion radiotherapy. Spot scanning method has been adapted for the beam delivery system of the radioactive beam. Dose distributions of the spot beam were measured and analyzed taking into account of aberration of the beam optics. Distributions of the stopped positron-emitter beam can be observed by PET. Pencil beam of the positron-emitter, about 1 mm size, can also be used for measurements ranges of the test beam in patients using positron camera. The positron camera, consisting of a pair of Anger-type scintillation detectors, has been developed for this verification before treatment. Wash-out effect of the positron-emitter was examined using the positron camera installed. In this report, present status of the HIMAC irradiation system is described in detail.

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

    NASA Astrophysics Data System (ADS)

    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

  5. Electron beam evaporated carbon doping of InGaAs layers grown by gas source molecular beam epitaxy

    SciTech Connect

    Salokatve, A.; Toivonen, M.; Asonen, H.; Pessa, M.; Likonen, J.

    1996-12-31

    The authors have studied carbon doping of GaInAs grown by gas-source molecular beam epitaxy. Graphite was used as a source material for carbon evaporation. GaInAs was studied due to its importance as a base layer in InP-based heterojunction bipolar transistors. They show that useful p-type acceptor concentrations can be achieved by evaporation from graphite source for GaInAs grown by gas-source molecular beam epitaxy. Secondary ion mass spectroscopy and Van der Pauw Hall measurements were used to characterize the carbon and net acceptor concentrations of their GaInAs layers. The effect of rapid thermal annealing on acceptor concentrations and Hall mobilities was also studied.

  6. Measurement of large angle fragments induced by 400 MeV n-1 carbon ion beams

    NASA Astrophysics Data System (ADS)

    Aleksandrov, Andrey; Consiglio, Lucia; De Lellis, Giovanni; Di Crescenzo, Antonia; Lauria, Adele; Montesi, Maria Cristina; Patera, Vincenzo; Sirignano, Chiara; Tioukov, Valeri

    2015-09-01

    The use of carbon ion beams in radiotherapy presents significant advantages when compared to traditional x-ray. In fact, carbon ions deposit their energy inside the human body at the end of their range, the Bragg peak. Unlike x-ray beams, where the energy deposition decreases exponentially inside the irradiated volume, the shape of carbon beams is sharp and focused. Advantages are an increased energy released in the cancer volume while minimizing the irradiation to healthy tissues. Currently, the use of carbon beams is limited by the poor knowledge we have about the effects of the secondary fragments on the irradiated tissues. The secondary particles produced and their angular distribution is crucial to determine the global dose deposition. The knowledge of the flux of secondary particles plays a key role in the real time monitoring of the dose profile in hadron therapy. We present a detector based on nuclear emulsions for fragmentation measurements that performs a sub-micrometric tridimensional spatial resolution, excellent multi-particle separation and large angle track recognition. Nuclear emulsions are assembled in order to realize a hybrid detector (emulsion cloud chamber (ECC)) made of 300 μm nuclear emulsion films alternated with lead as passive material. Data reported here have been obtained by exposing two ECC detectors to the fragments produced by a 400 MeV n-1 12C beam on a composite target at the GSI laboratory in Germany. The ECC was exposed inside a more complex detector, named FIRST, in order to collect fragments with a continuous angular distribution in the range 47°-81° with respect to the beam axis. Results on the angular distribution of fragments as well as their momentum estimations are reported here.

  7. Test beam performance of CDF plug upgrade EM calorimeter

    SciTech Connect

    Fukui, Y.

    1998-11-01

    CDF Plug Upgrade(tile-fiber) EM Calorimeter performed resolution of 15{percent}/{radical} (E) {circle_plus}0.7{percent} with non-linearity less than 1{percent} in a energy range of 5{endash}180 GeV at Fermilab Test Beam. Transverse uniformity of inside-tower-response of the EM Calorimeter was 2.2{percent} with 56 GeV positron, which was reduced to 1.0{percent} with response map correction. We observed 300 photo electron/GeV in the EM Calorimeter. Ratios of EM Calorimeter response to positron beam to that to {sup 137}C{sub s} Source was stable within 1{percent} in the period of 8 months. {copyright} {ital 1998 American Institute of Physics.}

  8. Effects of scattered radiation and beam quality on low contrast performance in cone beam breast CT

    NASA Astrophysics Data System (ADS)

    Altunbas, M. Cem; Shaw, Chris; Chen, Lingyun; Wang, Tianpeng; Tu, Shuju

    2006-03-01

    In this work, we investigated the effects of scattered radiation and beam quality on the low contrast performance relevant to cone beam breast CT imaging. For experiments, we used our benchtop conebeam CT system and constructed a phantom consisting of simulated fat and soft tissues. We varied the field of view (FOV) along the z direction to observe its effect on scattered radiation. The beam quality was altered by varying the tube voltage from 50 to 100 kV. We computed the contrast-to-noise ratio (CNR) from reconstructed images and normalized it to the square root of dose measured at the center of the phantom. The results were used as the figure of merit (FOM). The effect of the beam quality on the scatter to primary ratio (SPR) had minimal impact and the SPR was primarily dominated by the FOV. In the central section of the phantom, increasing the FOV from 4 to 16 cm resulted in drop of CNR in the order of 15-20% at any given kVp setting. For a given FOV, the beam quality had insignificant effect on the FOM in the central section of the phantom. In the peripheral section, a 10 % drop in FOM was observed when the kVp setting was increased from 50 to 100. At lower kVp values, the primary x-ray transmission through the thicker parts of the phantom was severely reduced. Under such circumstances, ring artifacts were observed due to imperfect flat field correction at very low signal intensities. Higher kVp settings and higher SPRs helped to increase the signal intensity in highly attenuating regions and suppressed the ring artifacts.

  9. Multi-pulsed intense electron beam emission from velvet, carbon fibers, carbon nano-tubes and dispenser cathodes

    NASA Astrophysics Data System (ADS)

    Xia, Lian-Sheng; Yang, An-Min; Chen, Yi; Zhang, Huang; Liu, Xing-Guang; Li, Jin; Jiang, Xiao-Guo; Zhang, Kai-Zhi; Shi, Jin-Shui; Deng, Jian-Jun; Zhang, Lin-Wen

    2010-11-01

    The experimental results of studies of four kinds of cathode emitting intense electron beams are demonstrated under multi-pulsed mode based on an experimental setup including two multi-pulse high voltage sources. The tested cathodes include velvet, carbon fibers, carbon nano-tubes (CNTs) and dispenser cathodes. The results indicate that all four are able to emit multi-pulsed beams. For velvet, carbon fiber and CNTs, the electron induced cathode plasma emission may be the main process and this means that there are differences in beam parameters from pulse to pulse. For dispenser cathodes tested in the experiment, although there is a little difference from pulse to pulse for some reason, thermal-electric field emission may be the main process.

  10. Using Pyrolysis Molecular Beam Mass Spectrometry to Characterize Soil Organic Carbon in Native Prairie Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to characterize soil organic carbon (SOC) with pyrolysis molecular beam mass spectrometry (py-MBMS) and then to determine correlations between the mass spectra and associated soil characterization data. Both soil carbon chemistry and the organic forms in which SOC is...

  11. Practical biological spread-out Bragg peak design for a carbon beam

    NASA Astrophysics Data System (ADS)

    Kim, Chang Hyeuk; Lee, Hwa-Ryun; Chang, Seduk; Jang, Hong Suk; Kim, Jeong Hwan; Park, Dong Wook; Hwang, Won Taek; Yang, Tea-Keun

    2015-10-01

    In radiation therapy, the carbon beams has more advantages with respect to biological properties then a proton beam. The carbon beam has a high linear energy transfer (LET) to the medium and a higher relative biological effectiveness (RBE). To design the spread-out Bragg peak (SOBP) of biological dose for a carbon beam, we propose a practical method using the linear-quadratic (LQ) model and the Geant4-based Monte Carlo simulation code. Various Bragg peak profiles and LETs were calculated for each slice in the target region. To generate an appropriate biological SOBP, we applied a set of weighting factors, which are power functions in terms of energy steps, to each obtained physical dose. The designed biological SOBP showed a uniformity of 1.34%.

  12. Fabrication of carbon layer coated FE-nanoparticles using an electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Kim, Hyun Bin; Jeun, Joon Pyo; Kang, Phil Hyun; Oh, Seung-Hwan

    2016-01-01

    A novel synthesis of carbon encapsulated Fe nanoparticles was developed in this study. Fe chloride (III) and polyacrylonitrile (PAN) were used as precursors. The crosslinking of PAN molecules and the nucleation of Fe nanoparticles were controlled by the electron beam irradiation dose. Stabilization and carbonization processes were carried out using a vacuum furnace at 275 °C and 1000 °C, respectively. Micro structures were evaluated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Fe nanoparticles were formed with diameters of 100 nm, and the Fe nanoparticles were encapsulated by carbon layers. As the electron beam irradiation dose increased, it was observed that the particle sizes decreased.

  13. The measurement results of carbon ion beam structure extracted by bent crystal from U-70 accelerator

    NASA Astrophysics Data System (ADS)

    Afonin, A. G.; Barnov, E. V.; Britvich, G. I.; Chesnokov, Yu A.; Chirkov, P. N.; Durum, A. A.; Kostin, M. Yu; Maisheev, V. A.; Pitalev, V. I.; Reshetnikov, S. F.; Yanovich, A. A.; Nazhmudinov, R. M.; Kubankin, A. S.; Shchagin, A. V.

    2016-07-01

    The carbon ion +6C beam with energy 25 GeV/nucleon was extracted by bent crystal from the U-70 ring. The bent angle of silicon crystal was 85 mrad. About 2×105 particles for 109 circulated ions in the ring were observed in beam line 4a after bent crystal. Geometrical parameters, time structure and ion beam structure were measured. The ability of the bent monocrystal to extract and generate ion beam with necessary parameters for regular usage in physical experiments is shown in the first time.

  14. Engineering catalytic activity via ion beam bombardment of catalyst supports for vertically aligned carbon nanotube growth

    DOE PAGESBeta

    Islam, A. E.; Zakharov, D.; Stach, E. A.; Nikoleav, P.; Amama, P. B.; Sargent, G.; Saber, S.; Huffman, D.; Erford, M.; Semiatin, S. L.; et al

    2015-09-16

    Carbon nanotube growth depends on the catalytic activity of metal nanoparticles on alumina or silica supports. The control on catalytic activity is generally achieved by variations in water concentration, carbon feed, and sample placement on a few types of alumina or silica catalyst supports obtained via thin film deposition. We have recently expanded the choice of catalyst supports by engineering inactive substrates like c-cut sapphire via ion beam bombardment. The deterministic control on the structure and chemistry of catalyst supports obtained by tuning the degree of beam-induced damage have enabled better regulation of the activity of Fe catalysts only inmore » the ion beam bombarded areas and hence enabled controllable super growth of carbon nanotubes. A wide range of surface characterization techniques were used to monitor the catalytically active surface engineered via ion beam bombardment. The proposed method offers a versatile way to control carbon nanotube growth in patterned areas and also enhances the current understanding of the growth process. As a result, with the right choice of water concentration, carbon feed and sample placement, engineered catalyst supports may extend the carbon nanotube growth yield to a level that is even higher than the ones reported here, and thus offers promising applications of carbon nanotubes in electronics, heat exchanger, and energy storage.« less

  15. Engineering catalytic activity via ion beam bombardment of catalyst supports for vertically aligned carbon nanotube growth

    SciTech Connect

    Islam, A. E.; Zakharov, D.; Stach, E. A.; Nikoleav, P.; Amama, P. B.; Sargent, G.; Saber, S.; Huffman, D.; Erford, M.; Semiatin, S. L.; Maruyama, B.

    2015-09-16

    Carbon nanotube growth depends on the catalytic activity of metal nanoparticles on alumina or silica supports. The control on catalytic activity is generally achieved by variations in water concentration, carbon feed, and sample placement on a few types of alumina or silica catalyst supports obtained via thin film deposition. We have recently expanded the choice of catalyst supports by engineering inactive substrates like c-cut sapphire via ion beam bombardment. The deterministic control on the structure and chemistry of catalyst supports obtained by tuning the degree of beam-induced damage have enabled better regulation of the activity of Fe catalysts only in the ion beam bombarded areas and hence enabled controllable super growth of carbon nanotubes. A wide range of surface characterization techniques were used to monitor the catalytically active surface engineered via ion beam bombardment. The proposed method offers a versatile way to control carbon nanotube growth in patterned areas and also enhances the current understanding of the growth process. As a result, with the right choice of water concentration, carbon feed and sample placement, engineered catalyst supports may extend the carbon nanotube growth yield to a level that is even higher than the ones reported here, and thus offers promising applications of carbon nanotubes in electronics, heat exchanger, and energy storage.

  16. Water equivalent thickness values of materials used in beams of protons, helium, carbon and iron ions

    PubMed Central

    Zhang, Rui; Taddei, Phillip J; Fitzek, Markus M; Newhauser, Wayne D

    2010-01-01

    Heavy charged particle beam radiotherapy for cancer is of increasing interest because it delivers a highly conformal radiation dose to the target volume. Accurate knowledge of the range of a heavy charged particle beam after it penetrates a patient’s body or other materials in the beam line is very important and is usually stated in terms of the water equivalent thickness (WET). However, methods of calculating WET for heavy charged particle beams are lacking. Our objective was to test several simple analytical formulas previously developed for proton beams for their ability to calculate WET values for materials exposed to beams of protons, helium, carbon and iron ions. Experimentally measured heavy charged particle beam ranges and WET values from an iterative numerical method were compared with the WET values calculated by the analytical formulas. Inmost cases, the deviations were within 1 mm. We conclude that the analytical formulas originally developed for proton beams can also be used to calculate WET values for helium, carbon and iron ion beams with good accuracy. PMID:20371908

  17. Water equivalent thickness values of materials used in beams of protons, helium, carbon and iron ions.

    PubMed

    Zhang, Rui; Taddei, Phillip J; Fitzek, Markus M; Newhauser, Wayne D

    2010-05-01

    Heavy charged particle beam radiotherapy for cancer is of increasing interest because it delivers a highly conformal radiation dose to the target volume. Accurate knowledge of the range of a heavy charged particle beam after it penetrates a patient's body or other materials in the beam line is very important and is usually stated in terms of the water equivalent thickness (WET). However, methods of calculating WET for heavy charged particle beams are lacking. Our objective was to test several simple analytical formulas previously developed for proton beams for their ability to calculate WET values for materials exposed to beams of protons, helium, carbon and iron ions. Experimentally measured heavy charged particle beam ranges and WET values from an iterative numerical method were compared with the WET values calculated by the analytical formulas. In most cases, the deviations were within 1 mm. We conclude that the analytical formulas originally developed for proton beams can also be used to calculate WET values for helium, carbon and iron ion beams with good accuracy. PMID:20371908

  18. Neutron beam design, development, and performance for neutron capture therapy

    SciTech Connect

    Harling, O.K.; Bernard, J.A. ); Zamenhof, R.G. )

    1990-01-01

    The report presents topics presented at a workshop on neutron beams and neutron capture therapy. Topics include: neutron beam design; reactor-based neutron beams; accelerator-based neutron beams; and dosimetry and treatment planning. Individual projects are processed separately for the databases. (CBS)

  19. Evaluation of beam delivery and ripple filter design for non-isocentric proton and carbon ion therapy

    NASA Astrophysics Data System (ADS)

    Grevillot, L.; Stock, M.; Vatnitsky, S.

    2015-10-01

    This study aims at selecting and evaluating a ripple filter design compatible with non-isocentric proton and carbon ion scanning beam treatment delivery for a compact nozzle. The use of non-isocentric treatments when the patient is shifted as close as possible towards the nozzle exit allows for a reduction in the air gap and thus an improvement in the quality of scanning proton beam treatment delivery. Reducing the air gap is less important for scanning carbon ions, but ripple filters are still necessary for scanning carbon ion beams to reduce the number of energy steps required to deliver homogeneous SOBP. The proper selection of ripple filters also allows a reduction in the possible transverse and depth-dose inhomogeneities that could appear in non-isocentric conditions in particular. A thorough review of existing ripple filter designs over the past 16 years is performed and a design for non-isocentric treatment delivery is presented. A unique ripple filter quality index (QIRiFi) independent of the particle type and energy and representative of the ratio between energy modulation and induced scattering is proposed. The Bragg peak width evaluated at the 80% dose level (BPW80) is proposed to relate the energy modulation of the delivered Bragg peaks and the energy layer step size allowing the production of homogeneous SOBP. Gate/Geant4 Monte Carlo simulations have been validated for carbon ion and ripple filter simulations based on measurements performed at CNAO and subsequently used for a detailed analysis of the proposed ripple filter design. A combination of two ripple filters in a series has been validated for non-isocentric delivery and did not show significant transverse and depth-dose inhomogeneities. Non-isocentric conditions allow a significant reduction in the spot size at the patient entrance (up to 350% and 200% for protons and carbon ions with range shifter, respectively), and therefore in the lateral penumbra in the patients.

  20. Evaluation of beam delivery and ripple filter design for non-isocentric proton and carbon ion therapy.

    PubMed

    Grevillot, L; Stock, M; Vatnitsky, S

    2015-10-21

    This study aims at selecting and evaluating a ripple filter design compatible with non-isocentric proton and carbon ion scanning beam treatment delivery for a compact nozzle. The use of non-isocentric treatments when the patient is shifted as close as possible towards the nozzle exit allows for a reduction in the air gap and thus an improvement in the quality of scanning proton beam treatment delivery. Reducing the air gap is less important for scanning carbon ions, but ripple filters are still necessary for scanning carbon ion beams to reduce the number of energy steps required to deliver homogeneous SOBP. The proper selection of ripple filters also allows a reduction in the possible transverse and depth-dose inhomogeneities that could appear in non-isocentric conditions in particular. A thorough review of existing ripple filter designs over the past 16 years is performed and a design for non-isocentric treatment delivery is presented. A unique ripple filter quality index (QIRiFi) independent of the particle type and energy and representative of the ratio between energy modulation and induced scattering is proposed. The Bragg peak width evaluated at the 80% dose level (BPW80) is proposed to relate the energy modulation of the delivered Bragg peaks and the energy layer step size allowing the production of homogeneous SOBP. Gate/Geant4 Monte Carlo simulations have been validated for carbon ion and ripple filter simulations based on measurements performed at CNAO and subsequently used for a detailed analysis of the proposed ripple filter design. A combination of two ripple filters in a series has been validated for non-isocentric delivery and did not show significant transverse and depth-dose inhomogeneities. Non-isocentric conditions allow a significant reduction in the spot size at the patient entrance (up to 350% and 200% for protons and carbon ions with range shifter, respectively), and therefore in the lateral penumbra in the patients. PMID:26418366

  1. Structural Modification of Single Wall and Multiwalled Carbon Nanotubes under Carbon, Nickel and Gold Ion Beam Irradiation

    SciTech Connect

    Jeet, Kiran; Jindal, V. K.; Dharamvir, Keya; Bharadwaj, L. M.

    2011-12-12

    Thin film samples of carbon nanotubes were irradiated with ion beam of carbon, nickel and gold. The irradiation results were characterized using Raman Spectroscopy. Modifications of the disorder mode (D mode) and the tangential mode (G mode) under different irradiation fluences were studied in detail. Raman results of carbon ion beam indicate the interesting phenomenon of ordering of the system under irradiation. Under the effect of nickel and gold ion irradiation, the structural evolution of CNTs occurs in three different stages. At lower fluences the process of healing occurs; at intermediate fluences damages on the surface of CNTs occurs and finally at very high fluences of the order of 1x10{sup 14} ions/cm{sup 2} the system gets amorphised.

  2. Electron-Muon Ranger: Performance in the MICE muon beam

    DOE PAGESBeta

    Adams, D.

    2015-12-16

    The Muon Ionization Cooling Experiment (MICE) will perform a detailed study of ionization cooling to evaluate the feasibility of the technique. To carry out this program, MICE requires an efficient particle-identification (PID) system to identify muons. The Electron-Muon Ranger (EMR) is a fully-active tracking-calorimeter that forms part of the PID system and tags muons that traverse the cooling channel without decaying. The detector is capable of identifying electrons with an efficiency of 98.6%, providing a purity for the MICE beam that exceeds 99.8%. Lastly, the EMR also proved to be a powerful tool for the reconstruction of muon momenta inmore » the range 100–280 MeV/c.« less

  3. Electron-Muon Ranger: Performance in the MICE muon beam

    SciTech Connect

    Adams, D.

    2015-12-16

    The Muon Ionization Cooling Experiment (MICE) will perform a detailed study of ionization cooling to evaluate the feasibility of the technique. To carry out this program, MICE requires an efficient particle-identification (PID) system to identify muons. The Electron-Muon Ranger (EMR) is a fully-active tracking-calorimeter that forms part of the PID system and tags muons that traverse the cooling channel without decaying. The detector is capable of identifying electrons with an efficiency of 98.6%, providing a purity for the MICE beam that exceeds 99.8%. Lastly, the EMR also proved to be a powerful tool for the reconstruction of muon momenta in the range 100–280 MeV/c.

  4. Electron-muon ranger: performance in the MICE muon beam

    NASA Astrophysics Data System (ADS)

    Adams, D.; Alekou, A.; Apollonio, M.; Asfandiyarov, R.; Barber, G.; Barclay, P.; de Bari, A.; Bayes, R.; Bayliss, V.; Bene, P.; Bertoni, R.; Blackmore, V. J.; Blondel, A.; Blot, S.; Bogomilov, M.; Bonesini, M.; Booth, C. N.; Bowring, D.; Boyd, S.; Bradshaw, T. W.; Bravar, U.; Bross, A. D.; Cadoux, F.; Capponi, M.; Carlisle, T.; Cecchet, G.; Charnley, C.; Chignoli, F.; Cline, D.; Cobb, J. H.; Colling, G.; Collomb, N.; Coney, L.; Cooke, P.; Courthold, M.; Cremaldi, L. M.; Debieux, S.; DeMello, A.; Dick, A.; Dobbs, A.; Dornan, P.; Drielsma, F.; Filthaut, F.; Fitzpatrick, T.; Franchini, P.; Francis, V.; Fry, L.; Gallagher, A.; Gamet, R.; Gardener, R.; Gourlay, S.; Grant, A.; Graulich, J. S.; Greis, J.; Griffiths, S.; Hanlet, P.; Hansen, O. M.; Hanson, G. G.; Hart, T. L.; Hartnett, T.; Hayler, T.; Heidt, C.; Hills, M.; Hodgson, P.; Hunt, C.; Husi, C.; Iaciofano, A.; Ishimoto, S.; Kafka, G.; Kaplan, D. M.; Karadzhov, Y.; Kim, Y. K.; Kuno, Y.; Kyberd, P.; Lagrange, J.-B.; Langlands, J.; Lau, W.; Leonova, M.; Li, D.; Lintern, A.; Littlefield, M.; Long, K.; Luo, T.; Macwaters, C.; Martlew, B.; Martyniak, J.; Masciocchi, F.; Mazza, R.; Middleton, S.; Moretti, A.; Moss, A.; Muir, A.; Mullacrane, I.; Nebrensky, J. J.; Neuffer, D.; Nichols, A.; Nicholson, R.; Nicola, L.; Noah Messomo, E.; Nugent, J. C.; Oates, A.; Onel, Y.; Orestano, D.; Overton, E.; Owens, P.; Palladino, V.; Pasternak, J.; Pastore, F.; Pidcott, C.; Popovic, M.; Preece, R.; Prestemon, S.; Rajaram, D.; Ramberger, S.; Rayner, M. A.; Ricciardi, S.; Roberts, T. J.; Robinson, M.; Rogers, C.; Ronald, K.; Rothenfusser, K.; Rubinov, P.; Rucinski, P.; Sakamato, H.; Sanders, D. A.; Sandström, R.; Santos, E.; Savidge, T.; Smith, P. J.; Snopok, P.; Soler, F. J. P.; Speirs, D.; Stanley, T.; Stokes, G.; Summers, D. J.; Tarrant, J.; Taylor, I.; Tortora, L.; Torun, Y.; Tsenov, R.; Tunnell, C. D.; Uchida, M. A.; Vankova-Kirilova, G.; Virostek, S.; Vretenar, M.; Warburton, P.; Watson, S.; White, C.; Whyte, C. G.; Wilson, A.; Wisting, H.; Yang, X.; Young, A.; Zisman, M.

    2015-12-01

    The Muon Ionization Cooling Experiment (MICE) will perform a detailed study of ionization cooling to evaluate the feasibility of the technique. To carry out this program, MICE requires an efficient particle-identification (PID) system to identify muons. The Electron-Muon Ranger (EMR) is a fully-active tracking-calorimeter that forms part of the PID system and tags muons that traverse the cooling channel without decaying. The detector is capable of identifying electrons with an efficiency of 98.6%, providing a purity for the MICE beam that exceeds 99.8%. The EMR also proved to be a powerful tool for the reconstruction of muon momenta in the range 100-280 MeV/c.

  5. Cancer stem cells: The potential of carbon ion beam radiation and new radiosensitizers (Review).

    PubMed

    Baek, Sung-Jae; Ishii, Hideshi; Tamari, Keisuke; Hayashi, Kazuhiko; Nishida, Naohiro; Konno, Masamitsu; Kawamoto, Koichi; Koseki, Jun; Fukusumi, Takahito; Hasegawa, Shinichiro; Ogawa, Hisataka; Hamabe, Atsushi; Miyo, Masaaki; Noguchi, Kozo; Seo, Yuji; Doki, Yuichiro; Mori, Masaki; Ogawa, Kazuhiko

    2015-11-01

    Cancer stem cells (CSCs) are a small population of cells in cancer with stem-like properties such as cell proliferation, multiple differentiation and tumor initiation capacities. CSCs are therapy-resistant and cause cancer metastasis and recurrence. One key issue in cancer therapy is how to target and eliminate CSCs, in order to cure cancer completely without relapse and metastasis. To target CSCs, many cell surface markers, DNAs and microRNAs are considered as CSC markers. To date, the majority of the reported markers are not very specific to CSCs and are also present in non-CSCs. However, the combination of several markers is quite valuable for identifying and targeting CSCs, although more specific identification methods are needed. While CSCs are considered as critical therapeutic targets, useful treatment methods remain to be established. Epigenetic gene regulators, microRNAs, are associated with tumor initiation and progression. MicroRNAs have been recently considered as promising therapeutic targets, which can alter the therapeutic resistance of CSCs through epigenetic modification. Moreover, carbon ion beam radiotherapy is a promising treatment for CSCs. Evidence indicates that the carbon ion beam is more effective against CSCs than the conventional X-ray beam. Combination therapies of radiosensitizing microRNAs and carbon ion beam radiotherapy may be a promising cancer strategy. This review focuses on the identification and treatment resistance of CSCs and the potential of microRNAs as new radiosensitizers and carbon ion beam radiotherapy as a promising therapeutic strategy against CSCs. PMID:26330103

  6. GPU-accelerated automatic identification of robust beam setups for proton and carbon-ion radiotherapy

    NASA Astrophysics Data System (ADS)

    Ammazzalorso, F.; Bednarz, T.; Jelen, U.

    2014-03-01

    We demonstrate acceleration on graphic processing units (GPU) of automatic identification of robust particle therapy beam setups, minimizing negative dosimetric effects of Bragg peak displacement caused by treatment-time patient positioning errors. Our particle therapy research toolkit, RobuR, was extended with OpenCL support and used to implement calculation on GPU of the Port Homogeneity Index, a metric scoring irradiation port robustness through analysis of tissue density patterns prior to dose optimization and computation. Results were benchmarked against an independent native CPU implementation. Numerical results were in agreement between the GPU implementation and native CPU implementation. For 10 skull base cases, the GPU-accelerated implementation was employed to select beam setups for proton and carbon ion treatment plans, which proved to be dosimetrically robust, when recomputed in presence of various simulated positioning errors. From the point of view of performance, average running time on the GPU decreased by at least one order of magnitude compared to the CPU, rendering the GPU-accelerated analysis a feasible step in a clinical treatment planning interactive session. In conclusion, selection of robust particle therapy beam setups can be effectively accelerated on a GPU and become an unintrusive part of the particle therapy treatment planning workflow. Additionally, the speed gain opens new usage scenarios, like interactive analysis manipulation (e.g. constraining of some setup) and re-execution. Finally, through OpenCL portable parallelism, the new implementation is suitable also for CPU-only use, taking advantage of multiple cores, and can potentially exploit types of accelerators other than GPUs.

  7. Rehabilitation of notch damaged steel beam using a carbon fiber reinforced multiphase-matrix composite

    SciTech Connect

    Zhou, HongYu; Attard, Dr. Thomas L.; Wang, Yanli; Wang, Jy-An John; Ren, Fei

    2013-01-01

    The retrofit of notch damaged steel beams is investigated via the experimental testing of nine wide-flange steel beam specimens and finite element simulation. Three notch configurations representing various damage levels were identified, and the beam specimens were retrofitted using CFRP laminates and a recently developed polymeric matrix composite - CarbonFlex - that exhibits superior energy dissipation and ductility properties, where the peak-load deflections were between 49.4% and 65.2% higher using the CarbonFlex-retrofitted beams. The results are attributed to the substantially higher damage tolerance capability of CarbonFlex than conventional CFRP. Finite element models were developed to investigate the damage processes and strain/ stress distributions near the notch tips. The numerical results match closely with the experimentally determined load-deflection curves and the strain fields obtained by the digital imaging correlations (DIC) system. Both experimental and numerical results clearly indicate the effectiveness of CarbonFlex, as a candidate retrofitting material, to retrofit damaged steel structures. Lastly, the micro-mechanisms by which CarbonFlex could sufficiently sustain a significant amount of the peak strength at large displacement ductility values are discussed with the aid of scanning electron microscopy (SEM) pictures.

  8. Advanced Electron Beam Ion Sources (EBIS) for 2-nd generation carbon radiotherapy facilities

    NASA Astrophysics Data System (ADS)

    Shornikov, A.; Wenander, F.

    2016-04-01

    In this work we analyze how advanced Electron Beam Ion Sources (EBIS) can facilitate the progress of carbon therapy facilities. We will demonstrate that advanced ion sources enable operation of 2-nd generation ion beam therapy (IBT) accelerators. These new accelerator concepts with designs dedicated to IBT provide beams better suited for therapy and, are more cost efficient than contemporary IBT facilities. We will give a sort overview of the existing new IBT concepts and focus on those where ion source technology is the limiting factor. We will analyse whether this limitation can be overcome in the near future thanks to ongoing EBIS development.

  9. Role of lattice structure and low temperature resistivity in fast-electron-beam filamentation in carbon

    NASA Astrophysics Data System (ADS)

    Dance, R. J.; Butler, N. M. H.; Gray, R. J.; MacLellan, D. A.; Rusby, D. R.; Scott, G. G.; Zielbauer, B.; Bagnoud, V.; Xu, H.; Robinson, A. P. L.; Desjarlais, M. P.; Neely, D.; McKenna, P.

    2016-01-01

    The influence of low temperature (eV to tens-of-eV) electrical resistivity on the onset of the filamentation instability in fast-electron transport is investigated in targets comprising of layers of ordered (diamond) and disordered (vitreous) carbon. It is shown experimentally and numerically that the thickness of the disordered carbon layer influences the degree of filamentation of the fast-electron beam. Strong filamentation is produced if the thickness is of the order of 60 μm or greater, for an electron distribution driven by a sub-picosecond, mid-1020 Wcm‑2 laser pulse. It is shown that the position of the vitreous carbon layer relative to the fast-electron source (where the beam current density and background temperature are highest) does not have a strong effect because the resistive filamentation growth rate is high in disordered carbon over a wide range of temperatures up to the Spitzer regime.

  10. Beam-hardening artifacts on computed tomography images caused by lanthanum carbonate hydrate in a patient on dialysis.

    PubMed

    Hayashi, Hiromitsu; Machida, Minoru; Sekine, Tetsuro; Yamaguchi, Hidenori; Kiriyama, Tomonari; Kumita, Shin-Ichiro

    2010-05-01

    Lanthanum carbonate hydrate is a nonaluminum, noncalcium phosphate binder containing lanthanum (La). It is effective in decreasing the serum phosphate level in patients on dialysis. Because the atomic number of the La contained in lanthanum carbonate hydrate is relatively high, at 57, this agent may cause strong artifacts on computed tomography (CT) images, which may be mistakenly interpreted as foreign bodies. We recently performed CT examination of a patient on Fosrenol chewable tablets (i.e., lanthanum carbonate hydrate). The CT images were difficult to evaluate because of strong beam hardening artifacts, and differentiation from foreign body aspiration was required. We report here our experience and a discussion of the characteristics of this artifact. PMID:20512553

  11. Studies on the Performance of RC Beam-Column Joints Strengthened Using Different Composite Materials

    NASA Astrophysics Data System (ADS)

    Sheela, S.; Anu Geetha, B.

    2012-02-01

    Many reinforced concrete structures in our country are in a deteriorated or distressed state. Hence strengthening such structures or reducing the load limit on them is becoming necessary to extend their service life. Beam-column joint is the crucial zone in a reinforced concrete moment resisting frame since it is subjected to large forces during severe ground shaking. In the present study, an attempt has been made to determine the cost-effective composite material and optimum number of layers of composite material for strengthening beam-column joints. Specimens were strengthened using ferrocement, glass fibre reinforced polymer (GFRP) and carbon fibre reinforced polymer (CFRP) and studied their behaviour under static as well as cyclic loading. It was found that the rotation at ultimate moment of all the strengthened beam-column joints were greater than that of the control specimens. The specimens strengthened with more number of layers of strengthening material showed better moment-rotation characteristics. The joints strengthened using GFRP showed better performance in terms of ultimate load, moment rotation characteristics, ductility, energy absorption capacity and strength-to-cost ratio, when compared to that of the specimens strengthened with other composite materials. However, CFRP strengthened specimens showed good ductility and better cracking characteristics and prevented the failure at the joint.

  12. Quasi-steady carbon plasma source for neutral beam injector

    NASA Astrophysics Data System (ADS)

    Koguchi, H.; Sakakita, H.; Kiyama, S.; Shimada, T.; Sato, Y.; Hirano, Y.

    2014-02-01

    Carbon plasma is successfully sustained during 1000 s without any carrier gas in the bucket type ionization chamber with cusp magnetic field. Every several seconds, seed plasmas having ˜3 ms duration time are injected into the ionization chamber by a shunting arch plasma gun. The weakly ionized carbon plasma ejected from the shunting arch is also ionized by 2.45 GHz microwave at the electron cyclotron resonance surface and the plasma can be sustained even in the interval of gun discharges. Control of the gun discharge interval allows to keep high pressure and to sustain the plasma for long duration.

  13. Quasi-steady carbon plasma source for neutral beam injector.

    PubMed

    Koguchi, H; Sakakita, H; Kiyama, S; Shimada, T; Sato, Y; Hirano, Y

    2014-02-01

    Carbon plasma is successfully sustained during 1000 s without any carrier gas in the bucket type ionization chamber with cusp magnetic field. Every several seconds, seed plasmas having ∼3 ms duration time are injected into the ionization chamber by a shunting arch plasma gun. The weakly ionized carbon plasma ejected from the shunting arch is also ionized by 2.45 GHz microwave at the electron cyclotron resonance surface and the plasma can be sustained even in the interval of gun discharges. Control of the gun discharge interval allows to keep high pressure and to sustain the plasma for long duration. PMID:24593646

  14. Quasi-steady carbon plasma source for neutral beam injector

    SciTech Connect

    Koguchi, H. Sakakita, H.; Kiyama, S.; Shimada, T.; Sato, Y.; Hirano, Y.

    2014-02-15

    Carbon plasma is successfully sustained during 1000 s without any carrier gas in the bucket type ionization chamber with cusp magnetic field. Every several seconds, seed plasmas having ∼3 ms duration time are injected into the ionization chamber by a shunting arch plasma gun. The weakly ionized carbon plasma ejected from the shunting arch is also ionized by 2.45 GHz microwave at the electron cyclotron resonance surface and the plasma can be sustained even in the interval of gun discharges. Control of the gun discharge interval allows to keep high pressure and to sustain the plasma for long duration.

  15. SU-E-T-509: Validation of the Use of OSLD for Carbon Beam Remote Dosimetry

    SciTech Connect

    Summers, P; Lowenstein, J; Alvarez, P; Followill, D; Jakel, O; Prokesch, H

    2014-06-01

    Purpose: To describe the commissioning of Aluminum Oxide Optically Stimulated Luminescent Dosimeters (OSLD) for the use in Carbon beam remote dosimetry for centers participating in NCI-funded cooperative group clinical trials. Methods: As Carbon therapy centers express interest in participating in cooperative group clinical trials, the Imaging and Radiation Oncology Core Group (IROC) Houston QA Center (formerly RPC) is developing a way to remotely monitor the machine output of these Carbon facilities. OSLD have been commissioned for photon, electron and proton dosimetry, so an experiment was designed to commission the same dosimeters for Carbon. OSLD were irradiated in a Carbon therapy beam produced by the Siemens synchrotron at the Heidelberg Ion Therapy facility in Heidelberg, Germany. The OSLD were placed in acrylic phantoms, imaged with a CT scanner, and plans were developed using the Siemens treatment planning system. The OSLD were irradiated in uniform fields with maximum energies of 216, 301, and 402 MeV and at dose levels of 50, 100, 200 and 300 cGy. Results: The response of the OSLD in the Carbon beam, as compared to the Cobalt-60 reference condition, required an energy correction of 1.85 to account for the particle correction. OSLD dose calculations typically have a linearity correction to account for the change in response relative to the change in dose delivered. However, the response of the OSLD in the Carbon beam was found to be independent of the dose level; thus the linearity correction is 1.00. Conclusion: IROC Houston has commissioned OSLD for the use of remote output checks for Carbon therapy facilities to help ensure consistency across clinical trial participants. Work supported by grant CA10953 (NCI, DHHS)

  16. Future carbon beams at SPIRAL1 facility: Which method is the most efficient?

    SciTech Connect

    Maunoury, L. Delahaye, P.; Dubois, M.; Dupuis, M.; Frigot, R.; Grinyer, J.; Jardin, P.; Leboucher, C.

    2014-02-15

    Compared to in-flight facilities, Isotope Separator On-Line ones can in principle produce significantly higher radioactive ion beam intensities. On the other hand, they have to cope with delays for the release and ionization which make the production of short-lived isotopes ion beams of reactive and refractory elements particularly difficult. Many efforts are focused on extending the capabilities of ISOL facilities to those challenging beams. In this context, the development of carbon beams is triggering interest [H. Frånberg, M. Ammann, H. W. Gäggeler, and U. Köster, Rev. Sci. Instrum. 77, 03A708 (2006); M. Kronberger, A. Gottberg, T. M. Mendonca, J. P. Ramos, C. Seiffert, P. Suominen, and T. Stora, in Proceedings of the EMIS 2012 [Nucl. Instrum. Methods Phys. Res. B Production of molecular sideband radioisotope beams at CERN-ISOLDE using a Helicon-type plasma ion source (to be published)]: despite its refractory nature, radioactive carbon beams can be produced from molecules (CO or CO{sub 2}), which can subsequently be broken up and multi-ionized to the required charge state in charge breeders or ECR sources. This contribution will present results of experiments conducted at LPSC with the Phoenix charge breeder and at GANIL with the Nanogan ECR ion source for the ionization of carbon beams in the frame of the ENSAR and EMILIE projects. Carbon is to date the lightest condensable element charge bred with an ECR ion source. Charge breeding efficiencies will be compared with those obtained using Nanogan ECRIS and charge breeding times will be presented as well.

  17. Digital-image-correlation-based experimental stress analysis of reinforced concrete beams, strengthened using carbon composites

    NASA Astrophysics Data System (ADS)

    Helm, Jeffrey; Kurtz, Stephen

    2004-12-01

    The strengthening of reinforced concrete beams through the use of epoxy-bonded carbon composites has been widely researched in the United States since 1991. Despite the widespread attention of researchers, however, there are no reliable methods of predicting the failure of the repaired and strengthened beams by peeling of the fiber reinforced polymer (FRP) material from the parent concrete. To better understand peeling failure, several investigators have presented analytical work to predict the distribution of stresses along the interface between the FRP and the concrete. Several closed-form solutions can be found in the literature to predict the levels of shear stress present between the bonded composite plate and the parent concrete beam. However, there has been very little experimental verification of these analytical predictions because few experiments on large-scale beams have had sufficient instrumentation to facilitate the comparison. Some experiments have been presented1 in which electrical resistance strain gages were placed along the length of the carbon plate in order to deduce the interfacial shear stress using first differences. This method, though very crude, demonstrated that there are substantial differences between the distributions of interfacial shear stresses in actual repaired beams versus the analytical predictions. This paper presents a new test program in which large-scale carbon-fiber-strengthened reinforced concrete beams are load-tested to failure, while employing digital image correlation (DIC) to record the strains in the carbon fiber plate. Relying on the linear elasticity of carbon fiber, the interfacial shear can be determined and compared with the analytical predictions of the literature. The focus of this paper is the presentation of the experimental shear stress distributions and comparisons of these distributions with previous results available in the literature.

  18. Digital-image-correlation-based experimental stress analysis of reinforced concrete beams strengthened using carbon composites

    NASA Astrophysics Data System (ADS)

    Helm, Jeffrey; Kurtz, Stephen

    2005-01-01

    The strengthening of reinforced concrete beams through the use of epoxy-bonded carbon composites has been widely researched in the United States since 1991. Despite the widespread attention of researchers, however, there are no reliable methods of predicting the failure of the repaired and strengthened beams by peeling of the fiber reinforced polymer (FRP) material from the parent concrete. To better understand peeling failure, several investigators have presented analytical work to predict the distribution of stresses along the interface between the FRP and the concrete. Several closed-form solutions can be found in the literature to predict the levels of shear stress present between the bonded composite plate and the parent concrete beam. However, there has been very little experimental verification of these analytical predictions because few experiments on large-scale beams have had sufficient instrumentation to facilitate the comparison. Some experiments have been presented1 in which electrical resistance strain gages were placed along the length of the carbon plate in order to deduce the interfacial shear stress using first differences. This method, though very crude, demonstrated that there are substantial differences between the distributions of interfacial shear stresses in actual repaired beams versus the analytical predictions. This paper presents a new test program in which large-scale carbon-fiber-strengthened reinforced concrete beams are load-tested to failure, while employing digital image correlation (DIC) to record the strains in the carbon fiber plate. Relying on the linear elasticity of carbon fiber, the interfacial shear can be determined and compared with the analytical predictions of the literature. The focus of this paper is the presentation of the experimental shear stress distributions and comparisons of these distributions with previous results available in the literature.

  19. Evaluation of w values for carbon beams in air, using a graphite calorimeter.

    PubMed

    Sakama, Makoto; Kanai, Tatsuaki; Fukumura, Akifumi; Abe, Kyoko

    2009-03-01

    Despite recent progress in carbon therapy, accurate values for physical data such as the w value in air or stopping power ratios for ionization chamber dosimetry have not been obtained. The absorbed dose to graphite obtained with the graphite calorimeter was compared with that obtained using the ionization chambers following the IAEA protocol in order to evaluate the w values in air for mono-energetic carbon beams of 135, 290, 400 and 430 MeV/n. Two cylindrical chambers (PTW type 30001 and PTW type 30011, Farmer) and two plane-parallel chambers (PTW type 23343, Markus and PTW type 34001, Roos) calibrated by the absorbed dose to graphite and exposure to the (60)Co photon beam were used. The comparisons to our calorimeter measurements revealed that, using the ionization chambers, the absorbed dose to graphite comes out low by 2-6% in this experimental energy range and with these chamber types and calibration methods. In the therapeutic energy range, the w values in air for carbon beams indicated a slight energy dependence; we, however, assumed these values to be constant for practical use because of the large uncertainty and unknown perturbation factors of the ionization chambers. The w values in air of the carbon beams were evaluated to be 35.72 J C(-1) +/- 1.5% in the energy range used in this study. This value is 3.5% larger than that recommended by the IAEA TRS 398 for heavy-ion beams. Using this evaluated result, the absorbed dose to water in the carbon beams would be increased by the same amount. PMID:19174597

  20. Reactions of carbon atoms in pulsed molecular beams

    SciTech Connect

    Reisler, H.

    1993-12-01

    This research program consists of a broad scope of experiments designed to unravel the chemistry of atomic carbon in its two spin states, P and D, by using well-controlled initial conditions and state-resolved detection of products. Prerequisite to the proposed studies (and the reason why so little is known about carbon atom reactions), is the development of clean sources of carbon atoms. Therefore, in parallel with the studies of its chemistry and reaction dynamics, the authors continuously explore new, state-specific and efficient ways of producing atomic carbon. In the current program, C({sup 3}P) is produced via laser ablation of graphite, and three areas of study are being pursued: (i) exothermic reactions with small inorganic molecules (e.g., O{sub 2}, N{sub 2}O, NO{sub 2}) that can proceed via multiple pathways; (ii) the influence of vibrational and translational energy on endothermic reactions involving H-containing reactants that yield CH products (e.g., H{sub 2}O H{sub 2}CO); (iii) reactions of C({sup 3}P) with free radicals (e.g., HCO, CH{sub 3}O). In addition, the authors plan to develop a source of C({sup 1}D) atoms by exploiting the pyrolysis of diazotetrazole and its salts in the ablation source. Another important goal involves collaboration with theoreticians in order to obtain relevant potential energy surfaces, rationalize the experimental results and predict the roles of translational and vibrational energies.

  1. Characterization of laser beam interaction with carbon materials

    NASA Astrophysics Data System (ADS)

    Janićijević, Milovan; Srećković, Milesa; Kaluđerović, Branka; Bojanić, Slobodan; Družijanić, Dragan; Dinulović, Mirko; Kovačević, Aleksander

    2013-05-01

    This paper presents simulation and experimental results for the exposure of some carbon-based materials to alexandrite and Nd3+:YAG (yttrium aluminum garnet) laser radiation. Simulation of the heating effects was carried out using the COMSOL Multiphysics 3.5 package for samples of carbon-based P7295-2 fiber irradiated using an alexandrite laser and carbon-based P4396-2 fiber irradiated using an Nd3+:YAG laser, as well as by applying finite element modeling for P7295-2 samples irradiated using an Nd3+:YAG laser. In the experimental part, P7295-2 samples were exposed to alexandrite laser radiation while samples of carbon-based composite 3D C/C were exposed to Nd3+:YAG laser radiation. Micrographs of the laser induced craters were obtained by light and scanning electron microscopy, and the images analyzed using the ImageJ software. The results obtained enable identification of the laser-material interaction spots, and characterization of the laser induced changes in the materials investigated.

  2. Preliminary studies of PQS PET detector module for dose verification of carbon beam therapy

    NASA Astrophysics Data System (ADS)

    Kim, H.-I.; An, S. Jung; Lee, C. Y.; Jo, W. J.; Min, E.; Lee, K.; Kim, Y.; Joung, J.; Chung, Y. H.

    2014-05-01

    PET imaging can be used to verify dose distributions of therapeutic particle beams such as carbon ion beams. The purpose of this study was to develop a PET detector module which was designed for an in-beam PET scanner geometry integrated into a carbon beam therapy system, and to evaluate its feasibility as a monitoring system of patient dose distribution. A C-shaped PET geometry was proposed to avoid blockage of the carbon beam by the detector modules. The proposed PET system consisted of 14 detector modules forming a bore with 30.2 cm inner diameter for brain imaging. Each detector module is composed of a 9 × 9 array of 4.0 mm × 4.0 mm × 20.0 mm LYSO crystal module optically coupled with four 29 mm diameter PMTs using Photomultiplier-quadrant-sharing (PQS) technique. Because the crystal pixel was identified based upon the distribution of scintillation lights of four PMTs, the design of the reflector between crystal elements should be well optimized. The optical design of reflectors was optimized using DETECT2000, a Monte Carlo code for light photon transport. A laser-cut reflector set was developed using the Enhanced Specular Reflector (ESR, 3M Co.) mirror-film with a high reflectance of 98% and a thickness of 0.064 mm. All 81 crystal elements of detector module were identified. Our result demonstrates that the C-shaped PET system is under development and we present the first reconstructed image.

  3. Some Aspects of the Two Beam Performance of DCI

    SciTech Connect

    Krishnagopal, S.; Siemann, R.H.

    1991-09-01

    The results of beam-beam simulations that model DCI operating as an e{sup +}e{sup -} collider are reported. The simulation techniques, including a new procedure for incorporating synchrotron radiation, are described. Phase advance errors between the interaction points explain the beam-beam limit at the operating point q{sub x} = q{sub y} = 0.725 (q denotes the fractional part of the tune). The effects of radiation damping are also studied near that operating point. Simulation and experiments disagree in a second operating region, q{sub x} = q{sub y} {approx} 0.795, indicating additional physics outside the scope of our model.

  4. Interfacial electrical properties of ion-beam sputter deposited amorphous carbon on silicon

    NASA Technical Reports Server (NTRS)

    Khan, A. A.; Woollam, J. A.; Chung, Y.; Banks, B.

    1983-01-01

    Amorphous, 'diamond-like' carbon films have been deposited on Si substrates, using ion-beam sputtering. The interfacial properties are studied using capacitance and conductance measurements. Data are analyzed using existing theories for interfacial electrical properties. The density of electronic states at the interface, along with corresponding time constants are determined.

  5. Protective effects of shikonin on brain injury induced by carbon ion beam irradiation in mice.

    PubMed

    Gan, Lu; Wang, Zhen Hua; Zhang, Hong; Zhou, Rong; Sun, Chao; Liu, Yang; Si, Jing; Liu, Yuan Yuan; Wang, Zhen Guo

    2015-02-01

    Radiation encephalopathy is the main complication of cranial radiotherapy. It can cause necrosis of brain tissue and cognitive dysfunction. Our previous work had proved that a natural antioxidant shikonin possessed protective effect on cerebral ischemic injury. Here we investigated the effects of shikonin on carbon ion beam induced radiation brain injury in mice. Pretreatment with shikonin significantly increased the SOD and CAT activities and the ratio of GSH/GSSG in mouse brain tissues compared with irradiated group (P<0.01), while obviously reduced the MDA and PCO contents and the ROS levels derived from of the brain mitochondria. The shikonin also noticeably improved the spatial memory deficits caused by carbon ion beam irradiation. All results demonstrated that shikonin could improve the irradiated brain injury which might resulted from its modulation effects on the oxidative stress induced by the 12C6+ ion beam. PMID:25716567

  6. Investigation of industrial-scale carbon dioxide reduction using pulsed electron beams

    NASA Astrophysics Data System (ADS)

    Petrov, G. M.; Apruzese, J. P.; Petrova, Tz. B.; Wolford, M. F.

    2016-03-01

    Carbon dioxide is the most important greenhouse gas contributing to global warming. To help mitigate increasing CO2 concentrations, we investigate a method of carbon dioxide reduction using high-power electron beams, which can be used on an industrial scale. A series of experiments are conducted in which the reduction of CO2 is measured for different gas compositions and power deposition rates. An electron beam deposition model is applied to compute reduction rates of CO2 and energy cost for breaking a CO2 molecule in flue gas and pure carbon dioxide at atmospheric pressure. For flue gas consisting of 82% N2, 6% O2, and 12% CO2, the calculated energy cost is 85 eV per molecule. In order to dissociate 50% of the CO2 molecules, beam energy density deposition on the order of 20 J/cm3 is required. Electron beam irradiation of 12.6 liter gas volume containing 90% CO2 and 10% CH4 at beam energy density deposition of 4.2 J/cm3, accumulated over 43 shots in a 20 min interval, reduced the CO2 concentration to 78%. Analogous experiments with a gas mixture containing 11.5% CO2, 11.5% CH4, and balance of Ar, reduced the CO2 concentration to below 11% with energy deposition 0.71 J/cm3, accumulated over 10 shots in a 5 min interval. The experimental data and the theoretical predictions of CO2 reduction using pulsed electron beams are in agreement within the experimental error. Other techniques to enhance the removal of CO2 with pulsed electron beams are also explored, yielding new possible avenues of research.

  7. Analysis of carbon in SrTiO{sub 3} grown by hybrid molecular beam epitaxy

    SciTech Connect

    Jalan, Bharat; Cagnon, Joeel; Mates, Thomas E.; Stemmer, Susanne

    2009-11-15

    Secondary ion mass spectroscopy (SIMS) was used to investigate carbon impurity concentrations in stoichiometric SrTiO{sub 3} films grown by a hybrid molecular beam epitaxy approach that uses an effusion cell to supply strontium, a rf plasma source for oxygen and a metal organic titanium source (titanium tetra isopropoxide). The carbon concentration in the films was measured as a function of growth parameters. At sufficiently high growth temperatures (>800 degree sign C), the films contain a few ppm of carbon. The challenges in accurately quantifying low carbon concentrations are discussed. A carbon-containing contamination layer is detected on the surfaces of SrTiO{sub 3} substrates and air-exposed films by SIMS and in scanning transmission electron microscopy. The contamination layer could be removed by high-temperature predeposition oxygen plasma cleaning.

  8. Lifetime dependence of nitrided carbon stripper foils on sputter angle during N+ ion beam sputtering

    NASA Astrophysics Data System (ADS)

    Sugai, I.; Oyaizu, M.; Takeda, Y.; Kawakami, H.; Kawasaki, K.; Hattori, T.; Kadono, T.

    2015-09-01

    We fabricated high-lifetime thin nitride carbon stripper (NCS) foils with high nitrogen contents using ion-beam sputtering with reactive nitrogen gas and investigated the dependence of their lifetimes on the sputter angle. The nitrogen in carbon foils plays a critical role in determining their lifetime. Therefore, in order to investigate the effects of the nitrogen level in NCS foils on foil lifetime, we measured the sputtering yield for different sputter angles at a sputtering voltage of 10 kV while using carbon-based targets. We also measured the nitrogen-to-carbon thickness ratios of the foils using Rutherford backscattering spectrometry. The foils made at a sputter angle of 15° using a glassy amorphous carbon target exhibited an average increase of 200-fold in lifetime when compared to commercially available foils.

  9. Friction and Wear of Ion-Beam-Deposited Diamondlike Carbon on Chemical-Vapor-Deposited, Fine-Grain Diamond

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa; Wu, Richard L. C.; Lanter, William C.

    1996-01-01

    Friction and wear behavior of ion-beam-deposited diamondlike carbon (DLC) films coated on chemical-vapor-deposited (CVD), fine-grain diamond coatings were examined in ultrahigh vacuum, dry nitrogen, and humid air environments. The DLC films were produced by the direct impact of an ion beam (composed of a 3:17 mixture of Ar and CH4) at ion energies of 1500 and 700 eV and an RF power of 99 W. Sliding friction experiments were conducted with hemispherical CVD diamond pins sliding on four different carbon-base coating systems: DLC films on CVD diamond; DLC films on silicon; as-deposited, fine-grain CVD diamond; and carbon-ion-implanted, fine-grain CVD diamond on silicon. Results indicate that in ultrahigh vacuum the ion-beam-deposited DLC films on fine-grain CVD diamond (similar to the ion-implanted CVD diamond) greatly decrease both the friction and wear of fine-grain CVD diamond films and provide solid lubrication. In dry nitrogen and in humid air, ion-beam-deposited DLC films on fine-grain CVD diamond films also had a low steady-state coefficient of friction and a low wear rate. These tribological performance benefits, coupled with a wider range of coating thicknesses, led to longer endurance life and improved wear resistance for the DLC deposited on fine-grain CVD diamond in comparison to the ion-implanted diamond films. Thus, DLC deposited on fine-grain CVD diamond films can be an effective wear-resistant, lubricating coating regardless of environment.

  10. Performance of laser inter-satellite links with dynamic beam waist adjustment.

    PubMed

    Song, Tianyu; Wang, Qian; Wu, Ming-Wei; Kam, Pooi-Yuen

    2016-05-30

    In this paper, we propose the idea of dynamic beam waist adjustment for laser inter-satellite communications, and study the performance of this dynamic-beam scheme. The beam waist adjustment is based on continuous detection of the instantaneous pointing error angle, which is performed at the transmitter side. Using a square to approximate the circular detector region, we obtain a closed-form expression for calculating the proportion of power that can be collected by the receiver aperture, and derive a simple algebraic solution for the optimum dynamic beam waist. Due to its simple form, the dynamic beam waist value can be computed in real time at the transmitter, and therefore, the adjustment is practically implementable. It is shown that the performance of laser inter-satellite links with dynamic beam waist is better than that with fixed beam waist. PMID:27410117

  11. Effect of Electron Beam Irradiation on the Tensile Properties of Carbon Nanotubes Sheets and Yarns

    NASA Technical Reports Server (NTRS)

    Williams, Tiffany S.; Miller, Sandi G.; Baker, James S.; McCorkle, Linda S.; Meador, Michael A.

    2013-01-01

    Carbon nanotube sheets and yarns were irradiated using electron beam (e-beam) energy to determine the effect of irradiation dose on the tensile properties. Results showed that a slight change in tensile strength occurred after irradiating as-received CNT sheets for 20 minutes, and a slight decrease in tensile strength as the irradiation time approached 90 minutes. On the other hand, the addition of small molecules to the CNT sheet surface had a greater effect on the tensile properties of e-beam irradiated CNT sheets. Some functionalized CNT sheets displayed up to a 57% increase in tensile strength following 90 minutes of e-beam exposure. In addition, as-received CNT yarns showed a significant increase in tensile strength as the irradiation time increased.

  12. Experimental study on fatigue crack propagation rate of RC beam strengthened with carbon fiber laminate

    NASA Astrophysics Data System (ADS)

    Huang, Peiyan; Liu, Guangwan; Guo, Xinyan; Huang, Man

    2008-11-01

    The experimental research on fatigue crack propagation rate of reinforced concrete (RC) beams strengthened with carbon fiber laminate (CFL) is carried out by MTS system in this paper. The experimental results show that, the main crack propagation on strengthened beam can be summarized into three phases: 1) fast propagation phase; 2) steady propagation and rest phase; 3) unsteady propagation phase. The phase 2-i.e. steady propagation and rest stage makes up about 95% of fatigue life of the strengthened beam. The propagation rate of the main crack, da/dN, in phase 2 can be described by Paris formula, and the constant C and m can be confirmed by the fatigue crack propagation experiments of the RC beams strengthened with CFL under three-point bending loads.

  13. The RHIC p-Carbon CNI Polarimeter Upgrade For The Beam Polarization And Intensity Measurements

    SciTech Connect

    Zelenski, A.; Bazilevski, A.; Bunce, G.; Gill, R.; Huang, H.; Mahler, G.; Makdisi, Y.; Morozov, B.; Nemesure, S.; Russo, T.; Steski, D.; Sivertz, M.

    2009-08-04

    Proton polarization measurements in the AGS and RHIC (Relativistic Heavy Ion Collider at the beam energies 24-250 GeV) are based on proton-carbon and proton-proton elastic scattering in the Coulomb Nuclear Interference (CNI) region. Polarimeter operation in the scanning mode also gives polarization profile and beam intensity profile (beam emittance) measurements. Bunch by bunch emittance measurement is a very powerful tool for machine setup. Presently, the polarization and beam intensity profile measurements (in both vertical and horizontal planes) are restricted by the long target switching time and possible target destruction during this complicated motion. The RHIC polarimeters were operated near the limit of the counting rate for present silicon strip detectors. The ongoing polarimeter upgrade for the 2009 run will address all these problems. The upgrade should allow significant reduction of the polarization measurement errors by making feasible the complete polarization measurements, which includes polarization profiles in both the horizontal and vertical planes.

  14. Thermal and Mechanical Performance of a Carbon/Carbon Composite Spacecraft Radiator

    NASA Technical Reports Server (NTRS)

    Kuhn, Jonathan; Benner, Steve; Butler, Dan; Silk, Eric

    1999-01-01

    Carbon-carbon composite materials offer greater thermal efficiency, stiffness to weight ratio, tailorability, and dimensional stability than aluminum. These lightweight thermal materials could significantly reduce the overall costs associated with satellite thermal control and weight. However, the high cost and long lead-time for carbon-carbon manufacture have limited their widespread usage. Consequently, an informal partnership between government and industrial personnel called the Carbon-Carbon Spacecraft Radiator Partnership (CSRP) was created to foster carbon-carbon composite use for thermally and structurally demanding space radiator applications. The first CSRP flight opportunity is on the New Millennium Program (NMP) Earth Orbiter-1 (EO-1) spacecraft, scheduled for launch in late 1999. For EO-1, the CSRP designed and fabricated a Carbon-Carbon Radiator (CCR) with carbon-carbon facesheets and aluminum honeycomb core, which will also serve as a structural shear panel. While carbon-carbon is an ideal thermal candidate for spacecraft radiators, in practice there are technical challenges that may compromise performance. In this work, the thermal and mechanical performance of the EO-1 CCR is assessed by analysis and testing. Both then-nal and mechanical analyses were conducted to predict the radiator response to anticipated launch and on-orbit loads. The thermal model developed was based on thermal balance test conditions. The thermal analysis was performed using SINDA version 4.0. Structural finite element modeling and analysis were performed using SDRC/1-DEAS and UAI/NASTRAN, respectively. In addition, the CCR was subjected to flight qualification thermal/vacuum and vibration tests. The panel meets or exceeds the requirements for space flight and demonstrates promise for future satellite missions.

  15. The E-beam resist test facility: performance testing and benchmarking of E-beam resists for advanced mask writers

    NASA Astrophysics Data System (ADS)

    Malloy, Matt; Jang, Il Yong; Mellish, Mac; Litt, Lloyd C.; Raghunathan, Ananthan; Hartley, John

    2012-11-01

    With each new generation of e-beam mask writers comes the ability to write leading edge photomasks with improved patterning performance and increased throughput. However, these cutting-edge e-beam tools are often used with older generation resists, preventing the end-user from taking full advantage of the tool's potential. The generation gap between tool and resist will become even more apparent with the commercialization of multi-beam mask writers, which are expected to be available for pilot line use around 2015. The mask industry needs resists capable of meeting the resolution, roughness, and sensitivity requirements of these advanced tools and applications. The E-beam Resist Test Facility (ERTF) has been established to fill the need for consortium-based testing of e-beam resists for mask writing applications on advanced mask writers out to the 11nm half-pitch node and beyond. SEMATECH and the College of Nanoscale Science and Engineering (CNSE) began establishing the ERTF in early 2012 to test e-beam resist samples from commercial suppliers and university labs against the required performance metrics for each application at the target node. Operations officially began on June 12, 2012, at which time the first e-beam resist samples were tested. The ERTF uses the process and metrology infrastructure available at CNSE, including a Vistec VB300 Vectorscan e-beam tool adjusted to operate at 50kv. Initial testing results show that multiple resists already meet, or are close to meeting, the resolution requirements for mask writing at the 11nm node, but other metrics such as line width roughness still need improvement. An overview of the ERTF and its capabilities is provided here. Tools, baseline processes, and operation strategy details are discussed, and resist testing and benchmarking results are shown. The long-term outlook for the ERTF and plans to expand capability and testing capacity, including resist testing for e-beam direct write lithography, are also

  16. Carbon and carbon-coated electrodes for multistage depressed collectors for electron-beam devices - A technology review

    NASA Technical Reports Server (NTRS)

    Curren, Arthur N.

    1986-01-01

    Various aspects of carbon and carbon-coated multistaged depressed collector (MDC) electrode technology are reviewed. The physical properties of untreated graphite electrodes, ion-textured graphite electrodes, and textured, carbon-coated copper electrodes, and surface treatment procedures for these electrodes are described. The secondary electron emissions of the three electrode types are analyzed. MDC fabrication methods are discussed. The performances of MDCs fabricated with untreated graphite electrodes, ion-textured graphite electrodes, and textured, carbon-coated copper electrodes are evaluated. MDC and TWT efficiency levels for tubes fabricated with the three materials are measured.

  17. In silico carbon molecular beam epitaxial growth of graphene on the h-BN substrate: carbon source effect on van der Waals epitaxy.

    PubMed

    Lee, Jonghoon; Varshney, Vikas; Park, Jeongho; Farmer, Barry L; Roy, Ajit K

    2016-05-01

    Against the presumption that hexagonal boron-nitride (h-BN) should provide an ideal substrate for van der Waals (vdW) epitaxy to grow high quality graphene films, carbon molecular beam epitaxy (CMBE) techniques using solid carbon sublimation have reported relatively poor quality of the graphene. In this article, the CMBE growth of graphene on the h-BN substrate is numerically studied in order to identify the effect of the carbon source on the quality of the graphene film. The carbon molecular beam generated by the sublimation of solid carbon source materials such as graphite and glassy carbon is mostly composed of atomic carbon, carbon dimers and carbon trimers. Therefore, the graphene film growth becomes a complex process involving various deposition characteristics of a multitude of carbon entities. Based on the study of surface adsorption and film growth characteristics of these three major carbon entities comprising graphite vapour, we report that carbon trimers convey strong traits of vdW epitaxy prone to high quality graphene growth, while atomic carbon deposition is a surface-reaction limited process accompanied by strong chemisorption. The vdW epitaxial behaviour of carbon trimers is found to be substantial enough to nucleate and develop into graphene like planar films within a nanosecond of high flux growth simulation, while reactive atomic carbons tend to impair the structural integrity of the crystalline h-BN substrate upon deposition to form an amorphous interface between the substrate and the growing carbon film. The content of reactive atomic carbons in the molecular beam is suspected to be the primary cause of low quality graphene reported in the literature. A possible optimization of the molecular beam composition towards the synthesis of better quality graphene films is suggested. PMID:27108606

  18. Robust, easily shaped, and epoxy-free carbon-fiber-aluminum cathodes for generating high-current electron beams.

    PubMed

    Liu, Lie; Li, Limin; Wen, Jianchun; Wan, Hong

    2009-02-01

    This paper presents the construction of carbon-fiber-aluminum (CFA) cathode by squeezing casting and its applications for generating high-current electron beams to drive high-power microwave sources. The fabrication process avoided using epoxy, a volatile deteriorating the vacuum system. These cathodes had a higher hardness than conventional aluminum, facilitating machining. After surface treatment, carbon fibers became the dominator determining emission property. A multineedle CFA cathode was utilized in a triode virtual cathode oscillator (vircator), powered by a approximately 450 kV, approximately 400 ns pulse. It was found that 300-400 MW, approximately 250 ns microwave was radiated at a dominant frequency of 2.6 GHz. Further, this cathode can endure high-current-density emission without detectable degradation in performance as the pulse shot proceeded, showing the robust nature of carbon fibers as explosive emitters. Overall, this new class of cold cathodes offers a potential prospect of developing high-current electron beam sources. PMID:19256641

  19. Carbon ion beam focusing using laser irradiated heated diamond hemispherical shells

    SciTech Connect

    Offermann, Dustin T; Flippo, Kirk A; Gaillard, Sandrine A

    2009-01-01

    Experiments preformed at the Los Alamos National Laboratory's Trident Laser Facility were conducted to observe the acceleration and focusing of carbon ions via the TNSA mechanism using hemispherical diamond targets. Trident is a 200TW class laser system with 80J of 1 {micro}m, short-pulse light delivered in 0.5ps, with a peak intensity of 5 x 10{sup 20} W/cm{sup 2}. Targets where Chemical Vapor Deposition (CVD) diamonds formed into hemispheres with a radius of curvature of 400{micro}m and a thickness of 5{micro}m. The accelerated ions from the hemisphere were diagnosed by imaging the shadow of a witness copper mesh grid located 2mm behind the target onto a film pack located 5cm behind the target. Ray tracing was used to determine the location of the ion focal spot. The TNSA mechanism favorably accelerates hydrogen found in and on the targets. To make the carbon beam detectable, targets were first heated to several hundred degrees Celsius using a CW, 532nm, 8W laser. Imaging of the carbon beam was accomplished via an auto-radiograph of a nuclear activated lithium fluoride window in the first layer of the film pack. The focus of the carbon ion beam was determined to be located 630 {+-} 110 {micro}m from the vertex of the hemisphere.

  20. Optimizing the thermoelectric performance of zigzag and chiral carbon nanotubes

    PubMed Central

    2012-01-01

    Using nonequilibrium molecular dynamics simulations and nonequilibrium Green's function method, we investigate the thermoelectric properties of a series of zigzag and chiral carbon nanotubes which exhibit interesting diameter and chirality dependence. Our calculated results indicate that these carbon nanotubes could have higher ZT values at appropriate carrier concentration and operating temperature. Moreover, their thermoelectric performance can be significantly enhanced via isotope substitution, isoelectronic impurities, and hydrogen adsorption. It is thus reasonable to expect that carbon nanotubes may be promising candidates for high-performance thermoelectric materials. PMID:22325623

  1. Optical and scratch resistant properties of diamondlike carbon films deposited with single and dual ion beams

    NASA Technical Reports Server (NTRS)

    Kussmaul, Michael T.; Bogdanski, Michael S.; Banks, Bruce A.; Mirtich, Michael J.

    1993-01-01

    Amorphous diamondlike carbon (DLC) films were deposited using both single and dual ion beam techniques utilizing filament and hollow cathode ion sources. Continuous DLC films up to 3000 A thick were deposited on fused quartz plates. Ion beam process parameters were varied in an effort to create hard, clear films. Total DLC film absorption over visible wavelengths was obtained using a Perkin-Elmer spectrophotometer. An ellipsometer, with an Ar-He laser (wavelength 6328 A) was used to determine index of refraction for the DLC films. Scratch resistance and frictional and adherence properties were determined for select films. Applications for these films range from military to the ophthalmic industries.

  2. Optical and Scratch Resistant Properties of Diamondlike Carbon Films Deposited with Single and Dual Ion Beams

    NASA Technical Reports Server (NTRS)

    Kussmaul, Michael T.; Bogdanski, Michael S.; Banks, Bruce A.; Mirtich, Michael J.

    1993-01-01

    Amorphous diamond-like carbon (DLC) films were deposited using both single and dual ion beam techniques utilizing filament and hollow cathode ion sources. Continuous DLC films up to 3000 A thick were deposited on fused quartz plates. Ion beam process parameters were varied in an effort to create hard, clear films. Total DLC film absorption over visible wavelengths was obtained using a Perkin-Elmer spectrophotometer. An ellipsometer, with an Ar-He laser (wavelength 6328 A) was used to determine index of refraction for the DLC films. Scratch resistance, frictional, and adherence properties were determined for select films. Applications for these films range from military to the ophthalmic industries.

  3. Experimental study of the water-to-air stopping power ratio of monoenergetic carbon ion beams for particle therapy

    NASA Astrophysics Data System (ADS)

    Sánchez-Parcerisa, D.; Gemmel, A.; Jäkel, O.; Parodi, K.; Rietzel, E.

    2012-06-01

    Reference dosimetry with ionization chambers requires a number of chamber-specific and beam-specific calibration factors. For carbon ion beams, IAEA report TRS-398 yields a total uncertainty of 3% in the determination of the absorbed dose to water, for which the biggest contribution arises from the water-to-air stopping power ratio (sw, air), with an uncertainty of 2%. The variation of (sw, air) along the treatment field has been studied in several Monte Carlo works presented over the last few years. Their results were, in all cases, strongly dependent on the choice of mean ionization potentials (I-values) for air and water. A smaller dependence of (sw, air) with penetration depth was observed. Since a consensus on Iw, air and Iair has not yet been reached, the validity of such studies for clinical use cannot be assessed independently. Our approach is based on a direct experimental measurement of water-equivalent thicknesses of different air gaps at different beam energies. A theoretical expression describing the variation of the stopping power ratio with kinetic energy, sw,air(E), was derived from the Bethe-Bloch formula and fit to the measured data, yielding a coherent pair of Iw and Iair values with Iair/Iw = 1.157 ± 0.023. Additionally, the data from five different beam energies were combined in an average value of sw,air = 1.132 ± 0.003 (statistical) ± 0.003 (variation over energy range), valid for monoenergetic carbon ion beams at the plateau area of the depth dose distribution. A detailed uncertainty analysis was performed on the data, in order to assess the limitations of the method, yielding an overall standard uncertainty below 1% in sw,air(E). Therefore, when properly combined with the appropriate models for the fragment spectra, our experimental work can contribute to narrow the uncertainty margins currently in use in absorbed dose to water determination for dosimetry of carbon ion beam radiotherapy.

  4. Experimental study of the water-to-air stopping power ratio of monoenergetic carbon ion beams for particle therapy.

    PubMed

    Sánchez-Parcerisa, D; Gemmel, A; Jäkel, O; Parodi, K; Rietzel, E

    2012-06-01

    Reference dosimetry with ionization chambers requires a number of chamber-specific and beam-specific calibration factors. For carbon ion beams, IAEA report TRS-398 yields a total uncertainty of 3% in the determination of the absorbed dose to water, for which the biggest contribution arises from the water-to-air stopping power ratio (s(w, air)), with an uncertainty of 2%. The variation of (s(w, air)) along the treatment field has been studied in several Monte Carlo works presented over the last few years. Their results were, in all cases, strongly dependent on the choice of mean ionization potentials (I-values) for air and water. A smaller dependence of (s(w, air)) with penetration depth was observed. Since a consensus on I(w, air) and I(air) has not yet been reached, the validity of such studies for clinical use cannot be assessed independently. Our approach is based on a direct experimental measurement of water-equivalent thicknesses of different air gaps at different beam energies. A theoretical expression describing the variation of the stopping power ratio with kinetic energy, s(w,air)(E), was derived from the Bethe-Bloch formula and fit to the measured data, yielding a coherent pair of I(w) and I(air) values with I(air)/I(w) = 1.157 ± 0.023. Additionally, the data from five different beam energies were combined in an average value of s(w,air) = 1.132 ± 0.003 (statistical) ± 0.003 (variation over energy range), valid for monoenergetic carbon ion beams at the plateau area of the depth dose distribution. A detailed uncertainty analysis was performed on the data, in order to assess the limitations of the method, yielding an overall standard uncertainty below 1% in s(w,air)(E). Therefore, when properly combined with the appropriate models for the fragment spectra, our experimental work can contribute to narrow the uncertainty margins currently in use in absorbed dose to water determination for dosimetry of carbon ion beam radiotherapy. PMID:22596046

  5. Formation of Carbonized Polystyrene Sphere/hemisphere Shell Arrays by Ion Beam Irradiation and Subsequent Annealing or Chloroform Treatment

    NASA Astrophysics Data System (ADS)

    Song, Xianyin; Dai, Zhigao; Xiao, Xiangheng; Li, Wenqing; Zheng, Xudong; Shang, Xunzhong; Zhang, Xiaolei; Cai, Guangxu; Wu, Wei; Meng, Fanli; Jiang, Changzhong

    2015-12-01

    Heat-resistant two-dimensional (2D) sphere/hemisphere shell array is significant for the fabrication of novel nanostructures. Here large-area, well-ordered arrays of carbonized polystyrene (PS) hollow sphere/hemisphere with controlled size and morphology are prepared by combining the nanosphere self-assembly, kV Ag ion beam modification, and subsequent annealing or chloroform treatment. Potential mechanisms for the formation and evolution of the heat-resistant carbonized PS spherical shell with increasing ion fluence and energy are discussed. Combined with noble metal or semiconductor, these modified PS sphere arrays should open up new possibilities for high-performance nanoscale optical sensors or photoelectric devices.

  6. Formation of Carbonized Polystyrene Sphere/hemisphere Shell Arrays by Ion Beam Irradiation and Subsequent Annealing or Chloroform Treatment

    PubMed Central

    Song, Xianyin; Dai, Zhigao; Xiao, Xiangheng; Li, Wenqing; Zheng, Xudong; Shang, Xunzhong; Zhang, Xiaolei; Cai, Guangxu; Wu, Wei; Meng, Fanli; Jiang, Changzhong

    2015-01-01

    Heat-resistant two-dimensional (2D) sphere/hemisphere shell array is significant for the fabrication of novel nanostructures. Here large-area, well-ordered arrays of carbonized polystyrene (PS) hollow sphere/hemisphere with controlled size and morphology are prepared by combining the nanosphere self-assembly, kV Ag ion beam modification, and subsequent annealing or chloroform treatment. Potential mechanisms for the formation and evolution of the heat-resistant carbonized PS spherical shell with increasing ion fluence and energy are discussed. Combined with noble metal or semiconductor, these modified PS sphere arrays should open up new possibilities for high-performance nanoscale optical sensors or photoelectric devices. PMID:26640125

  7. Formation of Carbonized Polystyrene Sphere/hemisphere Shell Arrays by Ion Beam Irradiation and Subsequent Annealing or Chloroform Treatment.

    PubMed

    Song, Xianyin; Dai, Zhigao; Xiao, Xiangheng; Li, Wenqing; Zheng, Xudong; Shang, Xunzhong; Zhang, Xiaolei; Cai, Guangxu; Wu, Wei; Meng, Fanli; Jiang, Changzhong

    2015-01-01

    Heat-resistant two-dimensional (2D) sphere/hemisphere shell array is significant for the fabrication of novel nanostructures. Here large-area, well-ordered arrays of carbonized polystyrene (PS) hollow sphere/hemisphere with controlled size and morphology are prepared by combining the nanosphere self-assembly, kV Ag ion beam modification, and subsequent annealing or chloroform treatment. Potential mechanisms for the formation and evolution of the heat-resistant carbonized PS spherical shell with increasing ion fluence and energy are discussed. Combined with noble metal or semiconductor, these modified PS sphere arrays should open up new possibilities for high-performance nanoscale optical sensors or photoelectric devices. PMID:26640125

  8. Modeling and simulation performance of sucker rod beam pump

    SciTech Connect

    Aditsania, Annisa; Rahmawati, Silvy Dewi Sukarno, Pudjo; Soewono, Edy

    2015-09-30

    Artificial lift is a mechanism to lift hydrocarbon, generally petroleum, from a well to surface. This is used in the case that the natural pressure from the reservoir has significantly decreased. Sucker rod beam pumping is a method of artificial lift. Sucker rod beam pump is modeled in this research as a function of geometry of the surface part, the size of sucker rod string, and fluid properties. Besides its length, sucker rod string also classified into tapered and un-tapered. At the beginning of this research, for easy modeling, the sucker rod string was assumed as un-tapered. The assumption proved non-realistic to use. Therefore, the tapered sucker rod string modeling needs building. The numerical solution of this sucker rod beam pump model is computed using finite difference method. The numerical result shows that the peak of polished rod load for sucker rod beam pump unit C-456-D-256-120, for non-tapered sucker rod string is 38504.2 lb, while for tapered rod string is 25723.3 lb. For that reason, to avoid the sucker rod string breaks due to the overload, the use of tapered sucker rod beam string is suggested in this research.

  9. Modeling and simulation performance of sucker rod beam pump

    NASA Astrophysics Data System (ADS)

    Aditsania, Annisa; Rahmawati, Silvy Dewi; Sukarno, Pudjo; Soewono, Edy

    2015-09-01

    Artificial lift is a mechanism to lift hydrocarbon, generally petroleum, from a well to surface. This is used in the case that the natural pressure from the reservoir has significantly decreased. Sucker rod beam pumping is a method of artificial lift. Sucker rod beam pump is modeled in this research as a function of geometry of the surface part, the size of sucker rod string, and fluid properties. Besides its length, sucker rod string also classified into tapered and un-tapered. At the beginning of this research, for easy modeling, the sucker rod string was assumed as un-tapered. The assumption proved non-realistic to use. Therefore, the tapered sucker rod string modeling needs building. The numerical solution of this sucker rod beam pump model is computed using finite difference method. The numerical result shows that the peak of polished rod load for sucker rod beam pump unit C-456-D-256-120, for non-tapered sucker rod string is 38504.2 lb, while for tapered rod string is 25723.3 lb. For that reason, to avoid the sucker rod string breaks due to the overload, the use of tapered sucker rod beam string is suggested in this research.

  10. Performance of a High Resolution Cavity Beam Position Monitor System

    SciTech Connect

    Walston, S; Boogert, S; Chung, C; Fitsos, P; Frisch, J; Gronberg, J; Hayano, H; Honda, Y; Kolomensky, Y; Lyapin, A; Malton, S; May, J; McCormick, D; Meller, R; Miller, D; Orimoto, T; Ross, M; Slater, M; Smith, S; Smith, T; Terunuma, N; Thomson, M; Urakawa, J; Vogel, V; Ward, D; White, G

    2006-12-18

    It has been estimated that an RF cavity Beam Position Monitor (BPM) could provide a position measurement resolution of less than one nanometer. We have developed a high resolution cavity BPM and associated electronics. A triplet comprised of these BPMs was installed in the extraction line of the Accelerator Test Facility (ATF) at the High Energy Accelerator Research Organization (KEK) for testing with its ultra-low emittance beam. The three BPMs were each rigidly mounted inside an alignment frame on six variable-length struts which could be used to move the BPMs in position and angle. We have developed novel methods for extracting the position and tilt information from the BPM signals including a robust calibration algorithm which is immune to beam jitter. To date, we have demonstrated a position resolution of 15.6 nm and a tilt resolution of 2.1 {micro}rad over a dynamic range of approximately {+-} 20 {micro}m.

  11. Performance of a High Resolution Cavity Beam Position Monitor System

    SciTech Connect

    Walston, Sean; Boogert, Stewart; Chung, Carl; Fitsos, Joe; Frisch, Joe; Gronberg, Jeff; Hayano, Hitoshi; Honda, Yosuke; Kolomensky, Yury; Lyapin, Alexey; Malton, Stephen; May, Justin; McCormick, Douglas; Meller, Robert; Miller, David John; Orimoto, Toyoko; Ross, Marc; Slater, Mark; Smith, Steve; Smith, Tonee; Terunuma, Nobuhiro; /Fermilab /UC, Berkeley /LBL, Berkeley /Cambridge U. /Royal Holloway, U. of London /Cornell U., LNS /LLNL, Livermore /University Coll. London /SLAC /Caltech /KEK, Tsukuba

    2007-06-08

    It has been estimated that an RF cavity Beam Position Monitor (BPM) could provide a position measurement resolution of less than one nanometer. We have developed a high resolution cavity BPM and associated electronics. A triplet comprised of these BPMs was installed in the extraction line of the Accelerator Test Facility (ATF) at the High Energy Accelerator Research Organization (KEK) for testing with its ultra-low emittance beam. The three BPMs were each rigidly mounted inside an alignment frame on six variable-length struts which could be used to move the BPMs in position and angle. We have developed novel methods for extracting the position and tilt information from the BPM signals including a robust calibration algorithm which is immune to beam jitter. To date, we have demonstrated a position resolution of 15.6 nm and a tilt resolution of 2.1 {mu}rad over a dynamic range of approximately {+-} 20 {mu}m.

  12. Performance and beam characteristics of the Siemens Primus linear accelerator.

    PubMed

    Sontag, M R; Steinberg, T H

    1999-05-01

    Siemens Primus is a small footprint, klystron driven medical linear accelerator incorporating a compact solid state modulator. A double focused multileaf collimator (MLC) replaces the lower jaw. The first Primus in the world was installed at St. Jude Children's Research Hospital in early 1997 with x-ray energies of 6 and 15 MV and electron energies of 8, 10, 12, 15, 18, and 21 MeV. The 10 cm depth dose for a 100 cm SSD 10 X 10 cm2 beam is 68% and 77% for 6 and 15 MV x rays, respectively. For both x-ray energies, beam flatness is slightly better than the manufacturers specification of 3% and beam symmetry is considerably better than 1%. The double focus design of the MLC produces a sharp penumbra (5-7 mm at 6 MV and 6-8 mm at 15 MV), increasing modestly with beam size. MLC leaf leakage is less than 1.25%. The depths of the 80% depth dose for the six electron energies of 8, 10, 12, 15, 18, and 21 MeV are 2.6, 3.2, 4.0, 4.9, 6.0, and 7.4 cm, respectively. Beam flatness is typically 2%-3% for all electron energies except 21 MeV, where it reaches 4% for a 25 X 25 cm2 cone. Electron beam symmetry is better than 1% for all energies except 21 MeV, where it is equal to 1%. The results are stored electronically and may be retrieved using anonymous ftp from the American Institute of Physics, Physics Auxiliary Publication Service. PMID:10360534

  13. Radiological characteristics of MRI-based VIP polymer gel under carbon beam irradiation

    NASA Astrophysics Data System (ADS)

    Maeyama, T.; Fukunishi, N.; Ishikawa, K. L.; Furuta, T.; Fukasaku, K.; Takagi, S.; Noda, S.; Himeno, R.; Fukuda, S.

    2015-02-01

    We study the radiological characteristics of VIP polymer gel dosimeters under carbon beam irradiation with energy of 135 and 290 AMeV. To evaluate dose response of VIP polymer gels, the transverse (or spin-spin) relaxation rate R2 of the dosimeters measured by magnetic resonance imaging (MRI) as a function of linear energy transfer (LET), rather than penetration depth, as is usually done in previous reports. LET is evaluated by use of the particle transport simulation code PHITS. Our results reveal that the dose response decreases with increasing dose-averaged LET and that the dose response-LET relation also varies with incident carbon beam energy. The latter can be explained by taking into account the contribution from fragmentation products.

  14. Structure and performance of carbon aerogel electrodes

    SciTech Connect

    Pekala, R.W.; Mayer, S.T.; Poco, J.F.; Kaschmitter, J.L.

    1994-03-01

    The chemistry and physics of small clusters of atoms (1--100 nm) has received considerable attention in recent years because these assemblies often have properties between the molecular and bulk solid-state limits. The different properties can be explained in terms of the large fraction of atoms that are at the surface of a cluster as compared to the interior. Although the synthesis and properties of metal and. semiconductor clusters, metallocarbohedrenes, fullerenes, and nanotubes are the subject of extensive investigations, little attention has been paid to cluster-assembled porous materials. This oversight is of particular interest to us since we believe that aerogels are one of the few monolithic materials presently available where the benefits of cluster assembly can be demonstrated. In particular, the unique optical, thermal, acoustic, mechanical, and electrical properties of aerogels are directly related to their nanostructure, which is composed of interconnected particles (3--30 nm) with small interstitial pores (< 50 nm). This structure leads to extremely high surface areas (400--1100 m{sup 2}/g) with a large fraction of the atoms covering the surface of the interconnected particles. As a result of these structural features, carbon aerogels are finding applications as electrodes in supercapacitors with high energy and power densities.

  15. Advanced carbon-based material C60 modification using partially ionized cluster and energetic beams

    NASA Astrophysics Data System (ADS)

    Yuancheng, Du; Zhongmin, Ren; Zhifeng, Ying; Ning, Xu; Fuming, Li

    1997-06-01

    Two processes have been undertaken using Partially ionized cluster deposition (PICBD) and energetic ion bombardment beams deposition (IBD) respectively. C60 films deposited by PICBD at V=0 and 65 V, which result in highly textured close-packed structure in orientation (110) and being more polycrystalline respectively, the resistance of C60 films to oxygen diffusion contamination will be improved. In the case of PICBD, the ionized C60 soccer-balls molecules in the evaporation beams will be fragmented in collision with the substrate under the elevated accelerating fields Va. As a new synthetic IBD processing, two low energy (400 and 1000 eV) nitrogen ion beams have been used to bombard C60 films to synthesize the carbon nitride films.

  16. Demonstrated Efficient Quasi-Monoenergetic Carbon-Ion Beams Approaching Fast Ignition (FI) Requirements

    NASA Astrophysics Data System (ADS)

    Fernández, Juan C.; Palaniyappan, S.; Huang, C.; Gautier, D. C.; Santiago, M.

    2015-11-01

    Using massive computer simulations of relativistic laser-plasma interactions, we have identified a self-organizing scheme that exploits persisting self-generated plasma electric (~TV/m) and magnetic (~104 Tesla) fields to reduce the ion energy spread of intense laser-driven ion beams after the laser exits the plasma. Consistent with the scheme, we have demonstrated on the LANL Trident laser carbon-ion beams with narrow spectral peaks at 220 MeV, with high conversion efficiency (~ 5%). These parameters are within a factor of 2 of FI requirements. The remaining gap may be bridged by increasing the laser intensity by a factor of 4, according to our data. We also discuss how this beam may be focused, to address the remaining requirement for FI, besides the total laser energy. This work is sponsored by the LANL LDRD Program.

  17. Antimony-assisted carbonization of Si(111) with solid source molecular beam epitaxy

    SciTech Connect

    Hackley, Justin; Richardson, Christopher J. K.; Sarney, Wendy L.

    2013-11-15

    The carbonization of an antimony-terminated Si (111) surface in a solid source molecular beam epitaxy system is presented. Reflection high-energy electron diffraction, atomic force microscopy, x-ray photoelectron spectroscopy, and cross-sectional transmission electron microscopy are used to characterize samples grown with and without antimony termination. It is shown that the antimony-terminated surface promotes the formation of thin, smooth and continuous SiC films at a relatively low temperature of 800 °C.

  18. Focused-Ion-Beam-Milled Carbon Nanoelectrodes for Scanning Electrochemical Microscopy

    PubMed Central

    Chen, Ran; Hu, Keke; Yu, Yun; Mirkin, Michael V.; Amemiya, Shigeru

    2016-01-01

    Nanoscale scanning electrochemical microscopy (SECM) has emerged as a powerful electrochemical method that enables the study of interfacial reactions with unprecedentedly high spatial and kinetic resolution. In this work, we develop carbon nanoprobes with high electrochemical reactivity and well-controlled size and geometry based on chemical vapor deposition of carbon in quartz nanopipets. Carbon-filled nanopipets are milled by focused ion beam (FIB) technology to yield a flat disk tip with a thin quartz sheath as confirmed by transmission electron microscopy. The extremely high electroactivity of FIB-milled carbon nanotips is quantified by enormously high standard electron-transfer rate constants of ≥10 cm/s for Ru(NH3)63+. The tip size and geometry are characterized in electrolyte solutions by SECM approach curve measurements not only to determine inner and outer tip radii of down to ~27 and ~38 nm, respectively, but also to ensure the absence of a conductive carbon layer on the outer wall. In addition, FIB-milled carbon nanotips reveal the limited conductivity of ~100 nm-thick gold films under nanoscale mass-transport conditions. Importantly, carbon nanotips must be protected from electrostatic damage to enable reliable and quantitative nanoelectrochemical measurements.

  19. The atomistic mechanism of carbon nanotube cutting catalyzed by nickel under an electron beam

    NASA Astrophysics Data System (ADS)

    Lebedeva, Irina V.; Chamberlain, Thomas W.; Popov, Andrey M.; Knizhnik, Andrey A.; Zoberbier, Thilo; Biskupek, Johannes; Kaiser, Ute; Khlobystov, Andrei N.

    2014-11-01

    The cutting of single-walled carbon nanotubes by an 80 keV electron beam catalyzed by nickel clusters is imaged in situ using aberration-corrected high-resolution transmission electron microscopy. Extensive molecular dynamics simulations within the CompuTEM approach provide insight into the mechanism of this process and demonstrate that the combination of irradiation and the nickel catalyst is crucial for the cutting process to take place. The atomistic mechanism of cutting is revealed by a detailed analysis of irradiation-induced reactions of bond reorganization and atom ejection in the vicinity of the nickel cluster, showing a highly complex interplay of different chemical transformations catalysed by the metal cluster. One of the most prevalent pathways includes three consecutive stages: formation of polyyne carbon chains from the carbon nanotube, dissociation of the carbon chains into single and pairs of adatoms adsorbed on the nickel cluster, and ejection of these adatoms leading to the cutting of the nanotube. Significant variations in the atom ejection rate are discovered depending on the process stage and nanotube diameter. The revealed mechanism and kinetic characteristics of the cutting process provide fundamental knowledge for the development of new methodologies for control and manipulation of carbon structures at the nanoscale.The cutting of single-walled carbon nanotubes by an 80 keV electron beam catalyzed by nickel clusters is imaged in situ using aberration-corrected high-resolution transmission electron microscopy. Extensive molecular dynamics simulations within the CompuTEM approach provide insight into the mechanism of this process and demonstrate that the combination of irradiation and the nickel catalyst is crucial for the cutting process to take place. The atomistic mechanism of cutting is revealed by a detailed analysis of irradiation-induced reactions of bond reorganization and atom ejection in the vicinity of the nickel cluster, showing a

  20. Studies on PAN-based carbon fibers irradiated by Ar+ ion beams.

    PubMed

    Park, Soo-Jin; Seo, Min-Kang; Kim, Hak-Yong; Lee, Douk-Rae

    2003-05-15

    In this work, the effects of Ar+ ion beam irradiation on carbon fibers were studied using tensile and surface analytical techniques. The single-fiber pull-out test was executed in order to characterize the fiber/epoxy matrix interfacial adhesion. The Ar+ ion beam was irradiated using an ion-assisted reaction (IAR) method in reactive gas conditions under an oxygen environment with 1 x 10(16) ions/cm(2) Ar+ ion dose (ID), 6 sccm blown gas flow rate, and different ion beam energy intensities. From the experimental results, both the interfacial shear strength (IFSS) and fracture toughness (Gi) were found to increase with increasing Ar+ ion irradiation intensity. This was probably due to the fact that Ar+ ion beam irradiation on carbon fibers was effective in altering their surface physical chemistry and structural morphology, resulting in improved interfacial adhesion in the fiber/epoxy matrix. The reliability of single-fiber pull-out test data could be improved by statistical analysis using the Weibull distribution, which served to predict the variation of the mechanical interfacial properties in a composite system. PMID:16256547

  1. Mutagenic effects of carbon ion beam irradiations on dry Lotus japonicus seeds

    NASA Astrophysics Data System (ADS)

    Luo, Shanwei; Zhou, Libin; Li, Wenjian; Du, Yan; Yu, Lixia; Feng, Hui; Mu, Jinhu; Chen, Yuze

    2016-09-01

    Carbon ion beam irradiation is a powerful method for creating mutants and has been used in crop breeding more and more. To investigate the effects of carbon ion beams on Lotus japonicus, dry seeds were irradiated by 80 MeV/u carbon ion beam at dosages of 0, 100, 200, 300, 400, 500 and 600 Gy. The germination rate, survival rate and root length of M1 populations were explored and the dose of 400 Gy was selected as the median lethal dose (LD50) for a large-scale mutant screening. Among 2472 M2 plants, 127 morphological mutants including leaf, stem, flower and fruit phenotypic variation were found, and the mutation frequency was approximately 5.14%. Inter simple sequence repeat (ISSR) assays were utilized to investigate the DNA polymorphism between seven mutants and eight plants without phenotypic variation from M2 populations. No remarkable differences were detected between these two groups, and the total polymorphic rate was 0.567%.

  2. Performance of Conformable Phenolic Impregnated Carbon Ablator in Aerothermal Environments

    NASA Technical Reports Server (NTRS)

    Thornton, Jeremy; Fan, Wendy; Stackpoole, Mairead; Kao, David; Skokova, Kristina; Chavez-Garcia, Jose

    2012-01-01

    Conformable Phenolic Impregnated Carbon Ablator, a cousin of Phenolic Impregnated Carbon Ablator (PICA), was developed at NASA Ames Research Center as a lightweight thermal protection system under the Fundamental Aeronautics Program. PICA is made using a brittle carbon substrate, which has a very low strain to failure. Conformable PICA is made using a flexible carbon substrate, a felt in this case. The flexible felt significantly increases the strain to failure of the ablator. PICA is limited by its thermal mechanical properties. Future NASA missions will require heatshields that are more fracture resistant than PICA and, as a result, NASA Ames is working to improve PICA's performance by developing conformable PICA to meet these needs. Research efforts include tailoring the chemistry of conformable PICA with varying amounts of additives to enhance mechanical properties and testing them in aerothermal environments. This poster shows the performance of conformable PICA variants in arc jets tests. Some mechanical and thermal properties will also be presented.

  3. Tilting of carbon encapsulated metallic nanocolumns in carbon-nickel nanocomposite films by ion beam assisted deposition

    SciTech Connect

    Krause, Matthias; Muecklich, Arndt; Zschornak, Matthias; Wintz, Sebastian; Gemming, Sibylle; Abrasonis, Gintautas; Oates, Thomas W. H.; Luis Endrino, Jose

    2012-07-30

    The influence of assisting low-energy ({approx}50-100 eV) ion irradiation effects on the morphology of C:Ni ({approx}15 at. %) nanocomposite films during ion beam assisted deposition (IBAD) is investigated. It is shown that IBAD promotes the columnar growth of carbon encapsulated metallic nanoparticles. The momentum transfer from assisting ions results in tilting of the columns in relation to the growing film surface. Complex secondary structures are obtained, in which a significant part of the columns grows under local epitaxy via the junction of sequentially deposited thin film fractions. The influence of such anisotropic film morphology on the optical properties is highlighted.

  4. Unusual High Oxygen Reduction Performance in All-Carbon Electrocatalysts

    PubMed Central

    Wei, Wei; Tao, Ying; Lv, Wei; Su, Fang-Yuan; Ke, Lei; Li, Jia; Wang, Da-Wei; Li, Baohua; Kang, Feiyu; Yang, Quan-Hong

    2014-01-01

    Carbon-based electrocatalysts are more durable and cost-effective than noble materials for the oxygen reduction reaction (ORR), which is an important process in energy conversion technologies. Heteroatoms are considered responsible for the excellent ORR performance in many carbon-based electrocatalysts. But whether an all-carbon electrocatalyst can effectively reduce oxygen is unknown. We subtly engineered the interfaces between planar graphene sheets and curved carbon nanotubes (G-CNT) and gained a remarkable activity/selectivity for ORR (larger current, and n = 3.86, ~93% hydroxide + ~7% peroxide). This performance is close to that of Pt; and the durability is much better than Pt. We further demonstrate the application of this G-CNT hybrid as an all-carbon cathode catalyst for lithium oxygen batteries.We speculate that the high ORR activity of this G-CNT hybrid stems from the localized charge separation at the interface of the graphene and carbon nanotube, which results from the tunneling electron transfer due to the Fermi level mismatch on the planar and curved sp2 surfaces. Our result represents a conceptual breakthrough and pioneers the new avenues towards practical all-carbon electrocatalysis. PMID:25189141

  5. Focused-electron-beam-induced processing (FEBIP) for emerging applications in carbon nanoelectronics

    NASA Astrophysics Data System (ADS)

    Fedorov, Andrei G.; Kim, Songkil; Henry, Mathias; Kulkarni, Dhaval; Tsukruk, Vladimir V.

    2014-12-01

    Focused-electron-beam-induced processing (FEBIP), a resist-free additive nanomanufacturing technique, is an actively researched method for "direct-write" processing of a wide range of structural and functional nanomaterials, with high degree of spatial and time-domain control. This article attempts to critically assess the FEBIP capabilities and unique value proposition in the context of processing of electronics materials, with a particular emphasis on emerging carbon (i.e., based on graphene and carbon nanotubes) devices and interconnect structures. One of the major hurdles in advancing the carbon-based electronic materials and device fabrication is a disjoint nature of various processing steps involved in making a functional device from the precursor graphene/CNT materials. Not only this multi-step sequence severely limits the throughput and increases the cost, but also dramatically reduces the processing reproducibility and negatively impacts the quality because of possible between-the-step contamination, especially for impurity-susceptible materials such as graphene. The FEBIP provides a unique opportunity to address many challenges of carbon nanoelectronics, especially when it is employed as part of an integrated processing environment based on multiple "beams" of energetic particles, including electrons, photons, and molecules. This avenue is promising from the applications' prospective, as such a multi-functional (electron/photon/molecule beam) enables one to define shapes (patterning), form structures (deposition/etching), and modify (cleaning/doping/annealing) properties with locally resolved control on nanoscale using the same tool without ever changing the processing environment. It thus will have a direct positive impact on enhancing functionality, improving quality and reducing fabrication costs for electronic devices, based on both conventional CMOS and emerging carbon (CNT/graphene) materials.

  6. Performance of MACACO Compton telescope for ion-beam therapy monitoring: first test with proton beams.

    PubMed

    Solevi, Paola; Muñoz, Enrique; Solaz, Carles; Trovato, Marco; Dendooven, Peter; Gillam, John E; Lacasta, Carlos; Oliver, Josep F; Rafecas, Magdalena; Torres-Espallardo, Irene; Llosá, Gabriela

    2016-07-21

    In order to exploit the advantages of ion-beam therapy in a clinical setting, delivery verification techniques are necessary to detect deviations from the planned treatment. Efforts are currently oriented towards the development of devices for real-time range monitoring. Among the different detector concepts proposed, Compton cameras are employed to detect prompt gammas and represent a valid candidate for real-time range verification. We present the first on-beam test of MACACO, a Compton telescope (multi-layer Compton camera) based on lanthanum bromide crystals and silicon photo-multipliers. The Compton telescope was first characterized through measurements and Monte Carlo simulations. The detector linearity was measured employing (22)Na and Am-Be sources, obtaining about 10% deviation from linearity at 3.44 MeV. A spectral image reconstruction algorithm was tested on synthetic data. Point-like sources emitting gamma rays with energy between 2 and 7 MeV were reconstructed with 3-5 mm resolution. The two-layer Compton telescope was employed to measure radiation emitted from a beam of 150 MeV protons impinging on a cylindrical PMMA target. Bragg-peak shifts were achieved via adjustment of the PMMA target location and the resulting measurements used during image reconstruction. Reconstructed Bragg peak profiles proved sufficient to observe peak-location differences within 10 mm demonstrating the potential of the MACACO Compton Telescope as a monitoring device for ion-beam therapy. PMID:27352107

  7. Performance of MACACO Compton telescope for ion-beam therapy monitoring: first test with proton beams

    NASA Astrophysics Data System (ADS)

    Solevi, Paola; Muñoz, Enrique; Solaz, Carles; Trovato, Marco; Dendooven, Peter; Gillam, John E.; Lacasta, Carlos; Oliver, Josep F.; Rafecas, Magdalena; Torres-Espallardo, Irene; Llosá, Gabriela

    2016-07-01

    In order to exploit the advantages of ion-beam therapy in a clinical setting, delivery verification techniques are necessary to detect deviations from the planned treatment. Efforts are currently oriented towards the development of devices for real-time range monitoring. Among the different detector concepts proposed, Compton cameras are employed to detect prompt gammas and represent a valid candidate for real-time range verification. We present the first on-beam test of MACACO, a Compton telescope (multi-layer Compton camera) based on lanthanum bromide crystals and silicon photo-multipliers. The Compton telescope was first characterized through measurements and Monte Carlo simulations. The detector linearity was measured employing 22Na and Am-Be sources, obtaining about 10% deviation from linearity at 3.44 MeV. A spectral image reconstruction algorithm was tested on synthetic data. Point-like sources emitting gamma rays with energy between 2 and 7 MeV were reconstructed with 3–5 mm resolution. The two-layer Compton telescope was employed to measure radiation emitted from a beam of 150 MeV protons impinging on a cylindrical PMMA target. Bragg-peak shifts were achieved via adjustment of the PMMA target location and the resulting measurements used during image reconstruction. Reconstructed Bragg peak profiles proved sufficient to observe peak-location differences within 10 mm demonstrating the potential of the MACACO Compton Telescope as a monitoring device for ion-beam therapy.

  8. Superior performance of cone beam tomography in detecting a calcaneus fracture

    PubMed Central

    Lohse, Christian; Catala-Lehnen, Philip; Regier, Marc; Heiland, Max

    2015-01-01

    Cone beam computed tomography is a state-of-the-art imaging tool, initially developed for dental and maxillofacial application. With its high resolution and low radiation dose, cone beam tomography has been expanding its application fields, for example, to diagnosis of traumata and fractures in the head and neck area. In this study, we demonstrate superior and satisfactory performance of cone beam tomography for the imaging of a calcaneus fracture in comparison to conventional X-ray and computed tomography. PMID:26605132

  9. Performance Studies of the Vibration Wire Monitor on the Test Stand with Low Energy Electron Beam

    NASA Astrophysics Data System (ADS)

    Okabe, Kota; Yoshimoto, Masahiro; Kinsho, Michikazu

    In the high intensity proton accelerator as the Japan Proton Accelerator Research Complex (J-PARC) accelerators, serious radiation and residual dose is induced by a small beam loss such a beam halo. Therefore, diagnostics of the beam halo formation is one of the most important issues to control the beam loss. For the beam halo monitor, the vibration wire monitor (VWM) has a potential for investigating the beam halo and weak beam scanning. The VWM has a wide dynamic range, high resolution and the VWM is not susceptible to secondary electrons and electric noises. We have studied the VWM features as a new beam-halo monitor on the test stand with low energy electron gun. The frequency shift of the irradiated vibration wire was confirmed about wire material and the electron beam profile measured by using the VWM was consistent with the results of the Faraday cup measurement. Also we calculated a temperature distribution on the vibration wire which is irradiated by the electron beam with the numerical simulation. The simulations have been fairly successful in reproducing the transient of the irradiated vibration wire frequency measured by test stand experiments. In this paper, we will report a result of performance evaluation for the VWM on the test stands and discuss the VWM for beam halo diagnostic

  10. Low-z gas stripper as an alternative to carbon foils for the acceleration of high-power uranium beams

    SciTech Connect

    Okuno, H.; Hershcovitch, A.; Fukunishi, N.; Goto, A.; Hasebe, H.; Imao, H.; Kamigaito, O.; Kase, M.; Kuboki, H.; Yano, Y.; Yokouchi, S.

    2011-04-23

    The RIKEN accelerator complex started feeding the next-generation exotic beam facility radioisotope beam factory (RIBF) with heavy-ion beams from 2007 after the successful commissioning of RIBF at the end of 2006. Many improvements made from 2007 to 2010 were instrumental in increasing the intensity of various heavy-ion beams. However, the available beam intensity of very heavy ion beams, especially uranium beams, is far below our goal of 1 p{mu}A (6 x 10{sup 12} particles/s). In order to achieve this goal, upgrade programs are already in progress; the programs include the construction of a new 28-GHz superconducting electron cyclotron resonance ion source and a new injector linac. However, the most serious problem, that of a charge stripper for high-power uranium beams, still remains unsolved, despite extensive research and development work using large foils mounted on a rotating cylinder and a N{sup 2} gas stripper. A gas stripper is free from problems related to lifetime, though the equilibrium charge state in this stripper is considerably lower than that in a carbon foil, owing to the absence of the density effect. Nevertheless, the merits of gas strippers motivated us to develop a low-Z gas stripper to achieve a higher equilibrium charge state even in gases. We measured the electron-loss and electron-capture cross sections of uranium ions in He gas as a function of their charge state at 11, 14, and 15 MeV/nucleon. The equilibrium charge states extracted from the intersection of the lines of the two cross sections were promisingly higher than those in N{sub 2} gas by more than 10. Simple simulations of charge development along the stripper thickness were performed by assuming the measured cross sections. The simulation results show that about 1 mg/cm{sup 2} of He gas should be accumulated to achieve a charge state higher than that of N{sub 2} gas, notwithstanding the difficulty in accumulation of this helium amount owing to its fast dispersion. However, we now

  11. Phase Space Generation for Proton and Carbon Ion Beams for External Users’ Applications at the Heidelberg Ion Therapy Center

    PubMed Central

    Tessonnier, Thomas; Marcelos, Tiago; Mairani, Andrea; Brons, Stephan; Parodi, Katia

    2016-01-01

    In the field of radiation therapy, accurate and robust dose calculation is required. For this purpose, precise modeling of the irradiation system and reliable computational platforms are needed. At the Heidelberg Ion Therapy Center (HIT), the beamline has been already modeled in the FLUKA Monte Carlo (MC) code. However, this model was kept confidential for disclosure reasons and was not available for any external team. The main goal of this study was to create efficiently phase space (PS) files for proton and carbon ion beams, for all energies and foci available at HIT. PSs are representing the characteristics of each particle recorded (charge, mass, energy, coordinates, direction cosines, generation) at a certain position along the beam path. In order to achieve this goal, keeping a reasonable data size but maintaining the requested accuracy for the calculation, we developed a new approach of beam PS generation with the MC code FLUKA. The generated PSs were obtained using an infinitely narrow beam and recording the desired quantities after the last element of the beamline, with a discrimination of primaries or secondaries. In this way, a unique PS can be used for each energy to accommodate the different foci by combining the narrow-beam scenario with a random sampling of its theoretical Gaussian beam in vacuum. PS can also reproduce the different patterns from the delivery system, when properly combined with the beam scanning information. MC simulations using PS have been compared to simulations, including the full beamline geometry and have been found in very good agreement for several cases (depth dose distributions, lateral dose profiles), with relative dose differences below 0.5%. This approach has also been compared with measured data of ion beams with different energies and foci, resulting in a very satisfactory agreement. Hence, the proposed approach was able to fulfill the different requirements and has demonstrated its capability for application to

  12. Low-Z gas stripper as an alternative to carbon foils for the acceleration of high-power uranium beams

    NASA Astrophysics Data System (ADS)

    Okuno, H.; Fukunishi, N.; Goto, A.; Hasebe, H.; Imao, H.; Kamigaito, O.; Kase, M.; Kuboki, H.; Yano, Y.; Yokouchi, S.; Hershcovitch, A.

    2011-03-01

    The RIKEN accelerator complex started feeding the next-generation exotic beam facility radioisotope beam factory (RIBF) with heavy-ion beams from 2007 after the successful commissioning of RIBF at the end of 2006. Many improvements made from 2007 to 2010 were instrumental in increasing the intensity of various heavy-ion beams. However, the available beam intensity of very heavy ion beams, especially uranium beams, is far below our goal of 1pμA (6×1012particles/s). In order to achieve this goal, upgrade programs are already in progress; the programs include the construction of a new 28-GHz superconducting electron cyclotron resonance ion source and a new injector linac. However, the most serious problem, that of a charge stripper for high-power uranium beams, still remains unsolved, despite extensive research and development work using large foils mounted on a rotating cylinder and a N2 gas stripper. A gas stripper is free from problems related to lifetime, though the equilibrium charge state in this stripper is considerably lower than that in a carbon foil, owing to the absence of the density effect. Nevertheless, the merits of gas strippers motivated us to develop a low-Z gas stripper to achieve a higher equilibrium charge state even in gases. We measured the electron-loss and electron-capture cross sections of uranium ions in He gas as a function of their charge state at 11, 14, and 15MeV/nucleon. The equilibrium charge states extracted from the intersection of the lines of the two cross sections were promisingly higher than those in N2 gas by more than 10. Simple simulations of charge development along the stripper thickness were performed by assuming the measured cross sections. The simulation results show that about 1mg/cm2 of He gas should be accumulated to achieve a charge state higher than that of N2 gas, notwithstanding the difficulty in accumulation of this helium amount owing to its fast dispersion. However, we now believe that the following two

  13. A two-bunch beam position monitor performance evaluation

    SciTech Connect

    Traller, R.; Medvedko, E.; Smith, S.; Aiello, R.

    1998-12-01

    New beam position processing electronics for the Linear Accelerator allow faster feedback and processing of both positron and electron bunch positions in a single machine pulse. More than 30 electron-positron beam position monitors (epBPMs) have been installed at SLAC in various applications and have met all design requirements. The SLC production electron bunch follows the positron bunch down the linac separated by 58.8 nS. The epBPM measures the position of both bunches with an accuracy of better than 5 {mu}m at nominal operating intensities. For SLC, the epBPMs have measured the position of bunches consisting of from 1 to 8{times}10{sup 10} particles per bunch. For PEP-II ({ital B} Factory) injection, epBPMs have been used with larger electrodes and several BPMs have been combined on a single cable set. The signals are separated for measurement in the epBPM by timing. In PEP-II injection we have measured the position of bunches of as little as 2{times}10{sup 9} particles per bunch. To meet the demands of SLC and PEP-II injection, the epBPM has been designed with three triggering modes: 1. As a self-triggering detector, it can trigger off the beam and hold the peak signal until read out by the control program. 2. The gated mode uses external timing signals to gate the beam trigger. 3. The external trigger mode uses the external timing signals offset with internal vernier delays to precisely catch peak signals in noisy environments. Finally, the epBPM also has built-in timing verniers capable of nulling errors in cable set fabrication and differences in channel-to-channel signal delay. Software has made all this functionality available through the SLC control system. {copyright} {ital 1998 American Institute of Physics.}

  14. A two-bunch beam position monitor performance evaluation

    SciTech Connect

    Traller, Robert; Medvedko, Evgeny; Smith, Steve; Aiello, Roberto

    1998-12-10

    New beam position processing electronics for the Linear Accelerator allow faster feedback and processing of both positron and electron bunch positions in a single machine pulse. More than 30 electron-positron beam position monitors (epBPMs) have been installed at SLAC in various applications and have met all design requirements. The SLC production electron bunch follows the positron bunch down the linac separated by 58.8 nS. The epBPM measures the position of both bunches with an accuracy of better than 5 {mu}m at nominal operating intensities. For SLC, the epBPMs have measured the position of bunches consisting of from 1 to 8x10{sup 10} particles per bunch. For PEP-II (B Factory) injection, epBPMs have been used with larger electrodes and several BPMs have been combined on a single cable set. The signals are separated for measurement in the epBPM by timing. In PEP-II injection we have measured the position of bunches of as little as 2x10{sup 9} particles per bunch. To meet the demands of SLC and PEP-II injection, the epBPM has been designed with three triggering modes: 1. As a self-triggering detector, it can trigger off the beam and hold the peak signal until read out by the control program. 2. The gated mode uses external timing signals to gate the beam trigger. 3. The external trigger mode uses the external timing signals offset with internal vernier delays to precisely catch peak signals in noisy environments. Finally, the epBPM also has built-in timing verniers capable of nulling errors in cable set fabrication and differences in channel-to-channel signal delay. Software has made all this functionality available through the SLC control system.

  15. A high-performance electron beam ion source

    SciTech Connect

    Alessi,J.; Beebe, E.; Bellavia, S.; Gould, O.; Kponou, A.; Lambiase, R.; Lockey, R.; McCafferty, D.; Okamura, M.; Pikin, A. I.; Raparia, D.; Ritter, J.; Syndstrup, L.

    2009-06-08

    At Brookhaven National Laboratory, a high current Electron Beam Ion Source (EBIS) has been developed as part of a new preinjector that is under construction to replace the Tandem Van de Graaffs as the heavy ion preinjector for the RHIC and NASA experimental programs. This preinjector will produce milliampere-level currents of essentially any ion species, with q/A {ge} 1/6, in short pulses, for injection into the Booster synchrotron. In order to produce the required intensities, this EBIS uses a 10A electron gun, and an electron collector designed to handle 300 kW of pulsed electron beam power. The EBIS trap region is 1.5 m long, inside a 5T, 2m long, 8-inch bore superconducting solenoid. The source is designed to switch ion species on a pulse-to-pulse basis, at a 5 Hz repetition rate. Singly-charged ions of the appropriate species, produced external to the EBIS, are injected into the trap and confined until the desired charge state is reached via stepwise ionization by the electron beam. Ions are then extracted and matched into an RFQ, followed by a short IH Linac, for acceleration to 2 MeV/A, prior to injection into the Booster synchrotron. An overview of the preinjector is presented, along with experimental results from the prototype EBIS, where all essential requirements have already been demonstrated. Design features and status of construction of the final high intensity EBIS is also be presented.

  16. Carbon doping in molecular beam epitaxy of GaAs from a heated graphite filament

    NASA Technical Reports Server (NTRS)

    Malik, R. J.; Nottenberg, R. N.; Schubert, E. F.; Walker, J. F.; Ryan, R. W.

    1988-01-01

    Carbon doping of GaAs grown by molecular beam epitaxy has been obtained for the first time by use of a heated graphite filament. Controlled carbon acceptor concentrations over the range of 10 to the 17th-10 to the 20th/cu cm were achieved by resistively heating a graphite filament with a direct current power supply. Capacitance-voltage, p/n junction and secondary-ion mass spectrometry measurements indicate that there is negligible diffusion of carbon during growth and with postgrowth rapid thermal annealing. Carbon was used for p-type doping in the base of Npn AlGaAs/GaAs heterojunction bipolar transistors. Current gains greater than 100 and near-ideal emitter heterojunctions were obtained in transistors with a carbon base doping of 1 x 10 to the 19th/cu cm. These preliminary results indicate that carbon doping from a solid graphite source may be an attractive substitute for beryllium, which is known to have a relatively high diffusion coefficient in GaAs.

  17. In situ mass measurement of electron-beam-induced nanometer-sized W-related deposits using a carbon nanotube cantilever

    SciTech Connect

    Sawaya, Shintaro; Akita, Seiji; Nakayama, Yoshikazu

    2006-11-06

    Using a carbon nanotube oscillator, the authors performed in situ measurements of densities of electron-beam-induced tungsten compounds with size of less than 100 nm. Total mass of the deposit was proportional to the deposition time. A higher deposition rate was obtained at lower electron-beam acceleration voltage. Density of the deposit decreased from 2.7 to 1.4 g/cm{sup 3} with increasing acceleration voltage from 5 to 15 kV. These results indicate that the increased density with low-acceleration voltage produces effective decomposition of W(CO){sub 6}.

  18. Impact of Intrafractional Bowel Gas Movement on Carbon Ion Beam Dose Distribution in Pancreatic Radiotherapy

    SciTech Connect

    Kumagai, Motoki; Hara, Ryusuke; Mori, Shinichiro Yanagi, Takeshi; Asakura, Hiroshi; Kishimoto, Riwa; Kato, Hirotoshi; Yamada, Shigeru; Kandatsu, Susumu; Kamada, Tadashi

    2009-03-15

    Purpose: To assess carbon ion beam dose variation due to bowel gas movement in pancreatic radiotherapy. Methods and Materials: Ten pancreatic cancer inpatients were subject to diagnostic contrast-enhanced dynamic helical CT examination under breath-holding conditions, which included multiple-phase dynamic CT with arterial, venous, and delayed phases. The arterial-venous phase and arterial-delayed phase intervals were 35 and 145 s, respectively. A compensating bolus was designed to cover the target obtained at the arterial phase. Carbon ion dose distribution was calculated by applying the bolus to the CT data sets at the other two phases. Results: Dose conformation to the clinical target volume was degraded by beam overshoot/undershoot due to bowel gas movement. The D95 for clinical target volume was degraded from 98.2% (range, 98.0-99.1%) of the prescribed dose to 94.7% (range, 88.0-99.0%) at 145 s. Excessive dosing to normal tissues varied among tissues and was, for example, 12.2 GyE/13.1 GyE (0 s/145 s) for the cord and 38.8 GyE/39.8 GyE (0 s/145 s) for the duodenum. The magnitude of beam overshoot/undershoot was particularly exacerbated from the anterior and left directions. Conclusions: Bowel gas movement causes dosimetric variation to the target during treatment for radiotherapy. The effect of bowel gas movement varies with beam angle, with greatest influence on the anterior-posterior and left-right beams.

  19. Performance of the (n,{gamma})-Based Positron Beam Facility NEPOMUC

    SciTech Connect

    Schreckenbach, K.; Hugenschmidt, C.; Piochacz, C.; Stadlbauer, M.; Loewe, B.; Maier, J.; Pikart, P.

    2009-01-28

    The in-pile positron source of NEPOMUC at the neutron source Heinz Maier-Leibnitz (FRM II) provides at the experimental site an intense beam of monoenergetic positrons with selectable energy between 15 eV and 3 keV. The principle of the source is based on neutron capture gamma rays produced by cadmium in a beam tube tip close to the reactor core. The gamma ray absorption in platinum produces positrons which are moderated and formed to the beam. An unprecedented beam intensity of 9.10{sup 8} e{sup +}/s is achieved (1 keV). The performance and applications of the facility are presented.

  20. Performance of the (n,γ)-Based Positron Beam Facility NEPOMUC

    NASA Astrophysics Data System (ADS)

    Schreckenbach, K.; Hugenschmidt, C.; Löwe, B.; Maier, J.; Pikart, P.; Piochacz, C.; Stadlbauer, M.

    2009-01-01

    The in-pile positron source of NEPOMUC at the neutron source Heinz Maier-Leibnitz (FRM II) provides at the experimental site an intense beam of monoenergetic positrons with selectable energy between 15 eV and 3 keV. The principle of the source is based on neutron capture gamma rays produced by cadmium in a beam tube tip close to the reactor core. The gamma ray absorption in platinum produces positrons which are moderated and formed to the beam. An unprecedented beam intensity of 9.108 e+/s is achieved (1 keV). The performance and applications of the facility are presented.

  1. Carbon Material Optimized Biocathode for Improving Microbial Fuel Cell Performance.

    PubMed

    Tursun, Hairti; Liu, Rui; Li, Jing; Abro, Rashid; Wang, Xiaohui; Gao, Yanmei; Li, Yuan

    2016-01-01

    To improve the performance of microbial fuel cells (MFCs), the biocathode electrode material of double-chamber was optimized. Alongside the basic carbon fiber brush, three carbon materials namely graphite granules, activated carbon granules (ACG) and activated carbon powder, were added to the cathode-chambers to improve power generation. The result shows that the addition of carbon materials increased the amount of available electroactive microbes on the electrode surface and thus promote oxygen reduction rate, which improved the generation performance of the MFCs. The Output current (external resistance = 1000 Ω) greatly increased after addition of the three carbon materials and maximum power densities in current stable phase increased by 47.4, 166.1, and 33.5%, respectively. Additionally, coulombic efficiencies of the MFC increased by 16.3, 64.3, and 20.1%, respectively. These results show that MFC when optimized with ACG show better power generation, higher chemical oxygen demands removal rate and coulombic efficiency. PMID:26858695

  2. Carbon Material Optimized Biocathode for Improving Microbial Fuel Cell Performance

    PubMed Central

    Tursun, Hairti; Liu, Rui; Li, Jing; Abro, Rashid; Wang, Xiaohui; Gao, Yanmei; Li, Yuan

    2016-01-01

    To improve the performance of microbial fuel cells (MFCs), the biocathode electrode material of double-chamber was optimized. Alongside the basic carbon fiber brush, three carbon materials namely graphite granules, activated carbon granules (ACG) and activated carbon powder, were added to the cathode-chambers to improve power generation. The result shows that the addition of carbon materials increased the amount of available electroactive microbes on the electrode surface and thus promote oxygen reduction rate, which improved the generation performance of the MFCs. The Output current (external resistance = 1000 Ω) greatly increased after addition of the three carbon materials and maximum power densities in current stable phase increased by 47.4, 166.1, and 33.5%, respectively. Additionally, coulombic efficiencies of the MFC increased by 16.3, 64.3, and 20.1%, respectively. These results show that MFC when optimized with ACG show better power generation, higher chemical oxygen demands removal rate and coulombic efficiency. PMID:26858695

  3. Performance of a fast acquisition system for in-beam PET monitoring tested with clinical proton beams

    NASA Astrophysics Data System (ADS)

    Piliero, M. A.; Bisogni, M. G.; Cerello, P.; Del Guerra, A.; Fiorina, E.; Liu, B.; Morrocchi, M.; Pennazio, F.; Pirrone, G.; Wheadon, R.

    2015-12-01

    In this work we present the performance of a fast acquisition system for in-beam PET monitoring during the irradiation of a PMMA phantom with a clinical proton beam. The experimental set-up was based on 4 independent detection modules. Two detection modules were placed at one side of a PMMA phantom and the other two modules were placed at the opposite side of the phantom. One detection module was composed of a Silicon Photon Multiplier produced by AdvanSiD coupled to a single scintillating LYSO crystal. The read-out system was based on the TOFPET ASIC managed by a Xilinx ML605 FPGA Evaluation Board (Virtex 6). The irradiation of the PMMA phantom was performed at the CNAO hadrontherapy facility (Pavia, Italy) with a 95 MeV pulsed proton beam. The pulsed time structure of the proton beam was reconstructed by each detection module. The β+ annihilation peak was successfully measured and the production of β+ isotopes emitters was observed as increasing number of 511 keV events detected during irradiation. Finally, after the irradiation, the half lives of the 11C and 15O radioactive isotopes were estimated.

  4. Influence of thermal history on the mechanical properties of carbon fiber-acrylate composites cured by electron beam and thermal processes

    SciTech Connect

    Vautard, Frederic; Ozcan, Soydan; Poland, Laura E; Meyer III, Harry M

    2013-01-01

    The mechanical properties of an acrylate resin and its carbon fiber composite, as well as the adhesion strength between them, were characterized in the case of thermal and electron beam curing. The thermal history during the cure was also recorded. It was shown that the properties of the matrix were similar but that the thermal history during the curing had a direct influence on the type of interactions that were generated at the interface, leading to different level of adhesion strength and level of performance for the associated composites. In the case of a thermal cure, the thermal profile allowed the generation of covalent bonding at the interface, leading to a high level of adhesion strength, which was not the case for electron beam curing. The thermal history during the cure appeared to be a determining parameter for the level of performance of composites cured by electron beam.

  5. Lithium Ion Battery Performance of Silicon Nanowires With Carbon Skin

    SciTech Connect

    Bogart, Timothy D.; Oka, Daichi; Lu, Xiaotang; Gu, Meng; Wang, Chong M.; Korgel, Brian A.

    2013-12-06

    Silicon (Si) nanomaterials have emerged as a leading candidate for next generation lithium-ion battery anodes. However, the low electrical conductivity of Si requires the use of conductive additives in the anode film. Here we report a solution-based synthesis of Si nanowires with a conductive carbon skin. Without any conductive additive, the Si nanowire electrodes exhibited capacities of over 2000 mA h g-1 for 100 cycles when cycled at C/10 and over 1200 mA h g-1 when cycled more rapidly at 1C against Li metal.. In situ transmission electron microscopy (TEM) observation reveals that the carbon skin performs dual roles: it speeds lithiation of the Si nanowires significantly, while also constraining the final volume expansion. The present work sheds light on ways to optimize lithium battery performance by smartly tailoring the nanostructure of composition of materials based on silicon and carbon.

  6. Performance of a 10 Gbps FSO System Implementing Novel Beam Tracking a Dynamic Buffering Modem

    NASA Technical Reports Server (NTRS)

    Kiriazes, John; Valencia, J. Emilio; Peach, Robert; Visone, Chris; Burdge, Geoffrey; Vickers, John; Leclerc, Troy; Sauer, Paul; Andrews, Larry; Phillips, Ron

    2012-01-01

    A 10 Gbps Free space optical (FSO) system implements beam tracking, a high dynamic range optical receiver, and a dynamic buffering packet modem. Performance was characterized at the 4.5 km Shuttle Landing Facility at Kennedy Space Center Florida.

  7. The atomistic mechanism of carbon nanotube cutting catalyzed by nickel under an electron beam.

    PubMed

    Lebedeva, Irina V; Chamberlain, Thomas W; Popov, Andrey M; Knizhnik, Andrey A; Zoberbier, Thilo; Biskupek, Johannes; Kaiser, Ute; Khlobystov, Andrei N

    2014-12-21

    The cutting of single-walled carbon nanotubes by an 80 keV electron beam catalyzed by nickel clusters is imaged in situ using aberration-corrected high-resolution transmission electron microscopy. Extensive molecular dynamics simulations within the CompuTEM approach provide insight into the mechanism of this process and demonstrate that the combination of irradiation and the nickel catalyst is crucial for the cutting process to take place. The atomistic mechanism of cutting is revealed by a detailed analysis of irradiation-induced reactions of bond reorganization and atom ejection in the vicinity of the nickel cluster, showing a highly complex interplay of different chemical transformations catalysed by the metal cluster. One of the most prevalent pathways includes three consecutive stages: formation of polyyne carbon chains from the carbon nanotube, dissociation of the carbon chains into single and pairs of adatoms adsorbed on the nickel cluster, and ejection of these adatoms leading to the cutting of the nanotube. Significant variations in the atom ejection rate are discovered depending on the process stage and nanotube diameter. The revealed mechanism and kinetic characteristics of the cutting process provide fundamental knowledge for the development of new methodologies for control and manipulation of carbon structures at the nanoscale. PMID:25363681

  8. Crystallization effects and diamond formation in amorphous carbon films under low energy ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Patsalas, P.; Logothetidis, S.

    2001-05-01

    The crystallization effects occurring in various types of amorphous carbon (a-C) thin films with different structure and bonding induced by post-growth low energy (<1.5 keV) Ar + ion beam irradiation are presented. Detailed X-ray diffraction (XRD) measurements were used to identify several allotropic forms of carbon such as graphite and diamond as well as SiC detected in a-C films after ion irradiation. The diamond and SiC nucleation occurs close to the a-C/Si interface, beyond the ion penetration depth suggesting a non-direct nucleation mechanism. The relative content, grain size, distribution and orientation of each particular crystalline phase in the films depend strongly on the microstructural characteristics of the as-grown films. We also consider the effects of ion energy and fluence and substrate material on the crystallization process in an effort to get a deeper insight of the fundamental mechanisms occurring during the interaction of various carbon materials with low energy ion beams.

  9. Soft-Templated Mesoporous Carbon-Carbon Nanotube Composites for High Performance Lithium-ion Batteries

    SciTech Connect

    Guo, Bingkun; Wang, Xiqing; Fulvio, Pasquale F.; Chi, Miaofang; Mahurin, Shannon M.; Sun, Xiao-Guang; Dai, Sheng

    2011-09-13

    Mesoporous carbon with homogeneously dispersed multi-walled carbon nanotubes (MWNTs) are synthesized via a one-step "brick and mortar" soft-templating approach. Nanocomposites exhibit a reversible lithium storage capacity of 900 mA h g⁻¹ and a good rate performance. Such homogeneous nanocomposites are ideal candidates for electric vehicle applications where high power and energy density are primary requirements.

  10. ASR DIAGNOSIS BY PETROGRAPHIC INVESTIGATION AND EVALUATION OF MECHANICAL PERFORMANCE OF ASR DETERIORATED PRETENSIONED PC BEAM

    NASA Astrophysics Data System (ADS)

    Tomiyama, Jun; Yamada, Kazuo; Kaneda, Kazuo; Iraha, Shigeo; Oshiro, Takeshi

    ASR diagnosis and evaluation of load carrying capacity have been performed on the pre-tensioned PC beam which was cut out of a national high way bridge. The bridge was replaced lately after 25years service due to ASR deterioration. Comprehensive investigations such as crack measurement, material strength test, petrographic investigation, beam bending test have been performed on the deteriorated beam. Cracks have been observed on all sides and the appearance has been classified as severe deterioration grade. Petrographic investigation concluded that the reacted mineral was mainly reactive cristobalite contained in andesite of fine aggregates and EPMA investigation found that the reaction seemed to be the final stage. The late expansive ASR has been superimposed by cryptocrystalline quartz in coarse aggregates and it is still in progress. Deteriorated concrete cores with no visual crack have reduced only 10% of compressive strength compared with design strength, but significant loss has been observed on the elastic modulus. The static bending load test on the deteriorated test beam showed 95% of design load capacity indicating that the visual deterioration on surfaces has affected slight damages at this moment. But loss of bending rigidity has been appeared on the deteriorated beam .after bending cracks have started. This comprehensive study including the petrographic diagnosis and the appraisal on mechanical performance of the deteriorated beam conclude that there is a possibility of ASR deterioration in progress and further loss of mechanical performance though the beam had some margin for loading capacity at this moment.

  11. In silico carbon molecular beam epitaxial growth of graphene on the h-BN substrate: carbon source effect on van der Waals epitaxy

    NASA Astrophysics Data System (ADS)

    Lee, Jonghoon; Varshney, Vikas; Park, Jeongho; Farmer, Barry L.; Roy, Ajit K.

    2016-05-01

    Against the presumption that hexagonal boron-nitride (h-BN) should provide an ideal substrate for van der Waals (vdW) epitaxy to grow high quality graphene films, carbon molecular beam epitaxy (CMBE) techniques using solid carbon sublimation have reported relatively poor quality of the graphene. In this article, the CMBE growth of graphene on the h-BN substrate is numerically studied in order to identify the effect of the carbon source on the quality of the graphene film. The carbon molecular beam generated by the sublimation of solid carbon source materials such as graphite and glassy carbon is mostly composed of atomic carbon, carbon dimers and carbon trimers. Therefore, the graphene film growth becomes a complex process involving various deposition characteristics of a multitude of carbon entities. Based on the study of surface adsorption and film growth characteristics of these three major carbon entities comprising graphite vapour, we report that carbon trimers convey strong traits of vdW epitaxy prone to high quality graphene growth, while atomic carbon deposition is a surface-reaction limited process accompanied by strong chemisorption. The vdW epitaxial behaviour of carbon trimers is found to be substantial enough to nucleate and develop into graphene like planar films within a nanosecond of high flux growth simulation, while reactive atomic carbons tend to impair the structural integrity of the crystalline h-BN substrate upon deposition to form an amorphous interface between the substrate and the growing carbon film. The content of reactive atomic carbons in the molecular beam is suspected to be the primary cause of low quality graphene reported in the literature. A possible optimization of the molecular beam composition towards the synthesis of better quality graphene films is suggested.Against the presumption that hexagonal boron-nitride (h-BN) should provide an ideal substrate for van der Waals (vdW) epitaxy to grow high quality graphene films, carbon

  12. Non uniform shrinkages of double-walled carbon nanotube as induced by electron beam irradiation

    SciTech Connect

    Zhu, Xianfang Li, Lunxiong; Gong, Huimin; Yang, Lan; Sun, Chenghua

    2014-09-01

    Electron beam-induced nanoinstabilities of pristine double-walled carbon nanotubes (DWCNTs) of two different configurations, one fixed at both ends and another fixed at only one end, were in-situ investigated in transmission electron microscope at room temperature. It was observed that the DWCNT fixed at both ends shrank in its diameter uniformly. Meanwhile, the DWCNT fixed at only one end intriguingly shrank preferentially from its free cap end along its axial direction whereas its diameter shrinkage was offset. A mechanism of “diffusion” along with “evaporation” at room temperature which is driven by the nanocurvature of the DWCNTs, and the athermal activation induced by the electron beam was proposed to elucidate the observed phenomena. The effect of the interlayer interaction of the DWCNTs was also discussed.

  13. Ranges of applicability for the continuum beam model in the mechanics of carbon nanotubes and nanorods

    NASA Technical Reports Server (NTRS)

    Harik, V. M.

    2001-01-01

    Limitations in the validity of the continuum beam model for carbon nanotubes (NTs) and nanorods are examined. Applicability of all assumptions used in the model is restricted by the two criteria for geometric parameters that characterize the structure of NTs. The key non-dimensional parameters that control the NT buckling behavior are derived via dimensional analysis of the nanomechanical problem. A mechanical law of geometric similitude for NT buckling is extended from continuum mechanics for different molecular structures. A model applicability map, where two classes of beam-like NTs are identified, is constructed for distinct ranges of non-dimensional parameters. Expressions for the critical buckling loads and strains are tailored for two classes of NTs and compared with the data provided by the molecular dynamics simulations. copyright 2001 Elsevier Science Ltd. All rights reserved.

  14. Performance and measurements of the AGS and Booster beams

    SciTech Connect

    Weng, W.T.

    1996-06-01

    In May 1995, the AGS reached its upgrade intensity goal of 6{times}10{sup 13} ppp, the highest world intensity record for a proton synchrotron on a single pulse basis. At the same time, the Booster reached 2.2{times}10{sup 13} ppp surpassing the design goal of 1.5{times}10{sup 13} ppp due to the introduction of second harmonic cavity during injection. The critical accelerator manipulations, such as resonance stopband corrections, second harmonics cavity, direct rf feedback, gamma-transition jump, longitudinal phase space dilution, and transverse instability damping, will be described as well as some beam measurements. Possible future intensity and brightness upgrades will also be reported. {copyright} {ital 1996 American Institute of Physics.}

  15. Electroanalytical performance of carbon films with near-atomic flatness.

    PubMed

    Ranganathan, S; McCreery, R L

    2001-03-01

    Physicochemical and electrochemical characterization of carbon films obtained by pyrolyzing a commercially available photoresist has been performed. Photoresist spin-coated on to a silicon wafer was pyrolyzed at 1,000 degrees C in a reducing atmosphere (95% nitrogen and 5% hydrogen) to produce conducting carbon films. The pyrolyzed photoresist films (PPF) show unusual surface properties compared to other carbon electrodes. The surfaces are nearly atomically smooth with a root-mean-square roughness of <0.5 nm. PPF have a very low background current and oxygen/carbon atomic ratio compared to conventional glassy carbon and show relatively weak adsorption of methylene blue and anthraquinone-2,6-disulfonate. The low oxygen/carbon ratio and the relative stability of PPF indicate that surfaces may be partially hydrogen terminated. The pyrolyzed films were compared to glassy carbon (GC) heat treated under the same conditions as pyrolysis to evaluate the electroanalytical utility of PPF. Heterogeneous electron-transfer kinetics of various redox systems were evaluated. For Ru(NH3)6(3+/2+), Fe(CN)6(3-/4-), and chlorpromazine, fresh PPF surfaces show electron-transfer rates similar to those on GC, but for redox systems such as Fe3+/2+, ascorbic acid, dopamine, and oxygen, the kinetics on PPF are slower. Very weak interactions between the PPF surface and these redox systems lead to their slow electron-transfer kinetics. Electrochemical anodization results in a simultaneous increase in background current, adsorption, and electron-transfer kinetics. The PPF surfaces can be chemically modified via diazonium ion reduction to yield a covalently attached monolayer. Such a modification could help in the preparation of low-cost, high-volume analyte-specific electrodes for diverse electroanalytical applications. Overall, pyrolysis of the photoresist yields an electrode surface with properties similar to a very smooth version of glassy carbon, with some important differences in surface

  16. Structural performance of notch damaged steel beams repaired with composite materials

    NASA Astrophysics Data System (ADS)

    El-Taly, Boshra

    2016-06-01

    An experimental program and an analytical model using ANSYS program were employed to estimate the structural performance of repaired damaged steel beams using fiber reinforced polymer (FRP) composite materials. The beams were artificially notched in the tension flanges at mid-spans and retrofitted by FRP flexible sheets on the tension flanges and the sheets were extended to cover parts of the beams webs with different heights. Eleven box steel beams, including one intact beam, one notch damaged beam and nine notches damaged beam and retrofitted with composite materials, were tested in two-point loading up to failure. The parameters considered were the FRP type (GFRP and CFRP) and number of layers. The results indicated that bonding CFRP sheets to both of the tension steel flange and part of the webs, instead of the tension flange only, enhances the ultimate load of the retrofitted beams, avoids the occurrence of the debonding and increases the beam ductility. Also the numerical models give acceptable results in comparison with the experimental results.

  17. Structural performance of notch damaged steel beams repaired with composite materials

    NASA Astrophysics Data System (ADS)

    El-Taly, Boshra

    2016-03-01

    An experimental program and an analytical model using ANSYS program were employed to estimate the structural performance of repaired damaged steel beams using fiber reinforced polymer (FRP) composite materials. The beams were artificially notched in the tension flanges at mid-spans and retrofitted by FRP flexible sheets on the tension flanges and the sheets were extended to cover parts of the beams webs with different heights. Eleven box steel beams, including one intact beam, one notch damaged beam and nine notches damaged beam and retrofitted with composite materials, were tested in two-point loading up to failure. The parameters considered were the FRP type (GFRP and CFRP) and number of layers. The results indicated that bonding CFRP sheets to both of the tension steel flange and part of the webs, instead of the tension flange only, enhances the ultimate load of the retrofitted beams, avoids the occurrence of the debonding and increases the beam ductility. Also the numerical models give acceptable results in comparison with the experimental results.

  18. Design and performance of an automated video-based laser beam alignment system

    SciTech Connect

    Rundle, W.J. ); Kartz, M.W. ); Bliss, E.S.; English, R.E. Jr.; Peterson, R.L.; Thompson, G.R.; Uhlich, D.M. )

    1992-07-14

    This paper describes the design and performance of an automated, closed-loop, laser beam alignment system. Its function is to sense a beam alignment error in a laser beam transport system and automatically steer mirrors preceding the sensor location as required to maintain beam alignment. The laser beam is sampled by an optomechanical package which uses video cameras to sense pointing and centering errors. The camera outputs are fed to an image processing module, which includes video digitizers and uses image storage and software to sense the centroid of the image. Signals are sent through a VMEbus to an optical device controller'' (ODC), which drives stepper-motor actuators on mirror mounts preceding the beam-sampling location to return the beam alignment to the prescribed condition. Photodiodes are also used to extend the control bandwidth beyond that which is achievable with video cameras. This system has been operated at LLNL in the Atomic Vapor Laser Isotope Separation (AVLIS) program to maintain the alignment of copper and dye laser beams, the latter to within [plus minus]2 [mu]r in pointing and less than 1 mm in centering. The optomechanical design of the instrumented package, which includes lens, mirror, and video mounts in a rigid housing, the automated control system architecture, and the performance of this equipment is described.

  19. Design and performance of an automated video-based laser beam alignment system

    SciTech Connect

    Rundle, W.J.; Kartz, M.W.; Bliss, E.S.; English, R.E. Jr.; Peterson, R.L.; Thompson, G.R.; Uhlich, D.M.

    1992-07-14

    This paper describes the design and performance of an automated, closed-loop, laser beam alignment system. Its function is to sense a beam alignment error in a laser beam transport system and automatically steer mirrors preceding the sensor location as required to maintain beam alignment. The laser beam is sampled by an optomechanical package which uses video cameras to sense pointing and centering errors. The camera outputs are fed to an image processing module, which includes video digitizers and uses image storage and software to sense the centroid of the image. Signals are sent through a VMEbus to an ``optical device controller`` (ODC), which drives stepper-motor actuators on mirror mounts preceding the beam-sampling location to return the beam alignment to the prescribed condition. Photodiodes are also used to extend the control bandwidth beyond that which is achievable with video cameras. This system has been operated at LLNL in the Atomic Vapor Laser Isotope Separation (AVLIS) program to maintain the alignment of copper and dye laser beams, the latter to within {plus_minus}2 {mu}r in pointing and less than 1 mm in centering. The optomechanical design of the instrumented package, which includes lens, mirror, and video mounts in a rigid housing, the automated control system architecture, and the performance of this equipment is described.

  20. Improving the electrochemical performance of carbon filaments by solvent cleansing

    SciTech Connect

    Shui, X.; Chung, D.D.L.; Frysz, C.A.

    1995-12-31

    Found inherent in the submicron-diameter vapor-grown carbon filament fabrication process was a tarry residue, which comprised polyaromatic hydrocarbons. Cyclic voltammetry conducted using carbon working electrodes and an iron cyanide electrolyte showed that the residue harmed the electrochemical performance. Removal of the residue from the filaments using a solvent resulted in increases in the electron transfer rate (to values as high as 0.2 cm/s) and reversibility of the iron cyanide redox species, increase in the packing density and decrease in the filament-filament contact electrical resistivity.

  1. Measurement of inclusive charged current interactions on carbon in a few-GeV neutrino beam

    SciTech Connect

    Nakajima, Y.; jima, Y.Naka; Alcaraz-Aunion, J.L.; Brice, S.J.; Bugel, L.; Catala-Perez, J.; Cheng, G.; Conrad, J.M.; Djurcic, Z.; Dore, U.; Finley, D.A.; /Kyoto U. /Barcelona, IFAE /Fermilab /MIT /Valencia U. /Columbia U. /MIT /Columbia U. /INFN, Rome /Rome U. /Fermilab /Columbia U. /INFN, Rome /Rome U.

    2010-11-01

    The SciBooNE Collaboration reports a measurement of inclusive charged current interactions of muon neutrinos on carbon with an average energy of 0.8 GeV using the Fermilab Booster Neutrino Beam. We compare our measurement with two neutrino interaction simulations: NEUT and NUANCE. The charged current interaction rates (product of flux and cross section) are extracted by fitting the muon kinematics, with a precision of 6-15% for the energy dependent and 3% for the energy integrated analyses. We also extract CC inclusive interaction cross sections from the observed rates, with a precision of 10-30% for the energy dependent and 8% for the energy integrated analyses. This is the first measurement of the CC inclusive cross section on carbon around 1 GeV. These results can be used to convert previous SciBooNE cross section ratio measurements to absolute cross section values.

  2. ENGINEERED INTERFACE CHEMISTRY TO IMPROVE THE MECHANICAL PROPERTIES OF CARBON FIBER COMPOSITES CURED BY ELECTRON BEAM

    SciTech Connect

    Vautard, Frederic; Grappe, Hippolyte A.; Ozcan, Soydan

    2014-01-01

    A reactive sizing was designed to achieve high levels of interfacial adhesion and mechanical properties with a carbon fiber-acrylate system cured by electron beam (EB). The sizing was made of a partially cured epoxy sizing with a high density of pendant functional groups (acrylate functionality) able to generate a covalent bonding with the matrix. The interlaminar shear strength was clearly improved from 61 MPa to 81 MPa (+ 33 %) without any post-processing, reaching a similar value to the one obtained with the same system cured by a thermal treatment. Observation of the fracture profiles clearly highlighted a change in the fracture mechanism from a purely adhesive failure to a cohesive failure. Such improvements of the mechanical properties of carbon fiber composites cured by EB, without any post-cure, have not been reported previously to the best of our knowledge. This constitutes a breakthrough for the industrial development of composites EB curing.

  3. Design and performance of a high resolution, low latency stripline beam position monitor system

    NASA Astrophysics Data System (ADS)

    Apsimon, R. J.; Bett, D. R.; Blaskovic Kraljevic, N.; Burrows, P. N.; Christian, G. B.; Clarke, C. I.; Constance, B. D.; Dabiri Khah, H.; Davis, M. R.; Perry, C.; Resta López, J.; Swinson, C. J.

    2015-03-01

    A high-resolution, low-latency beam position monitor (BPM) system has been developed for use in particle accelerators and beam lines that operate with trains of particle bunches with bunch separations as low as several tens of nanoseconds, such as future linear electron-positron colliders and free-electron lasers. The system was tested with electron beams in the extraction line of the Accelerator Test Facility at the High Energy Accelerator Research Organization (KEK) in Japan. It consists of three stripline BPMs instrumented with analogue signal-processing electronics and a custom digitizer for logging the data. The design of the analogue processor units is presented in detail, along with measurements of the system performance. The processor latency is 15.6 ±0.1 ns . A single-pass beam position resolution of 291 ±10 nm has been achieved, using a beam with a bunch charge of approximately 1 nC.

  4. Effect of Graphitic Content on Carbon Supported Catalyst Performance

    SciTech Connect

    A. Patel; K. Artyushkova; P. Atanassov; David Harvey; M. Dutta; V. Colbow; S. Wessel

    2011-07-01

    The effect of graphitic content on carbon supported platinum catalysts was investigated in order to investigate its influence on catalyst performance. Four catalysts of varying surface areas and graphitic content were analyzed using XPS, HREELS, and tested using RDE experiments. The catalysts were also heat treated at 150 C and 100%RH as means to uniformly age them. The heat treated samples were analyzed using the same methods to determine what changes had occurred due to this aging process. When compared to the BOL catalysts, heat treated catalysts displayed increased graphitic carbon and platinum metallic content, however they also showed depressed catalytic activity. The primary cause is still under investigation, though it is believed to be related to loss of amorphous carbon content.

  5. Effect of Graphitic Content on Carbon Supported Catalyst Performance

    SciTech Connect

    Patel, Anant; Artyushkova, Kateryna; Atanassov, Plamen; Harvey, David; Dutta, Monica; Colbow, Vesna

    2011-07-01

    The effect of graphitic content on carbon supported platinum catalysts was investigated in order to investigate its influence on catalyst performance. Four catalysts of varying surface areas and graphitic content were analyzed using XPS, HREELS, and tested using RDE experiments. The catalysts were also heat treated at 150oC and 100%RH as means to uniformly age them. The heat treated samples were analyzed using the same methods to determine what changes had occurred due to this aging process. When compared to the BOL catalysts, heat treated catalysts displayed increased graphitic carbon and platinum metalic content, however they also showed depressed catalytic activity. The primary cause is still under investigation, though it is believed to be related to loss of amorphous carbon content.

  6. Performance of Doublet III neutral beam injector cryopumping system

    SciTech Connect

    Langhorn, A.R.; Kim, J.; Tupper, M.L.; Williams, J.P.; Fasolo, J.

    1984-04-01

    The Doublet III neutral beam injector system is based on three beamlines; each beamline employs two 80 kV/80 A hydrogen ion sources. Two liquid helium (LHe) cooled cryopanel arrays were designed as an integral part of the beamline in order to provide high differential pumping of hydrogen gas along the beamline. The cryopanel arrays consist of a front (nearer to the torus) disk panel (3 m/sup 2/ each side) with liquid nitrogen (LN/sub 2/) cooled chevrons and a rear cylindrical panel of modified Santeler panels (8 m/sup 2/) which also employs LN/sub 2/ cooled surfaces shielding LHe cooled surfaces. These cryopanels are piped in series. The LHe delivery is based on a closed-loop, forced-flow scheme intended for variable panel temperatures (3.7 to 4.3 K). It uses small tubes for mechanical flexibility and thermal resiliency providing ease of economic defrosting. The cryogenic system consists of a liquefier (100 l/h), a large Dewar, a heat exchanger, and a liquid ring pump. Three beamlines are serviced simultaneously by the system. Pumping speeds measured locally at ionization gauges, were well in excess of the 1.4 x 10/sup 6/ l/s design goal.

  7. Thermally induced transformations of amorphous carbon nanostructures fabricated by electron beam induced deposition.

    PubMed

    Kulkarni, Dhaval D; Rykaczewski, Konrad; Singamaneni, Srikanth; Kim, Songkil; Fedorov, Andrei G; Tsukruk, Vladimir V

    2011-03-01

    We studied the thermally induced phase transformations of electron-beam-induced deposited (EBID) amorphous carbon nanostructures by correlating the changes in its morphology with internal microstructure by using combined atomic force microscopy (AFM) and high resolution confocal Raman microscopy. These carbon deposits can be used to create heterogeneous junctions in electronic devices commonly known as carbon-metal interconnects. We compared two basic shapes of EBID deposits: dots/pillars with widths from 50 to 600 nm and heights from 50 to 500 nm and lines with variable heights from 10 to 150 nm but having a constant length of 6 μm. We observed that during thermal annealing, the nanoscale amorphous deposits go through multistage transformation including dehydration and stress-relaxation around 150 °C, dehydrogenation within 150-300 °C, followed by graphitization (>350 °C) and formation of nanocrystalline, highly densified graphitic deposits around 450 °C. The later stage of transformation occurs well below commonly observed graphitization for bulk carbon (600-800 °C). It was observed that the shape of the deposits contribute significantly to the phase transformations. We suggested that this difference is controlled by different contributions from interfacial footprints area. Moreover, the rate of graphitization was different for deposits of different shapes with the lines showing a much stronger dependence of its structure on the density than the dots. PMID:21319745

  8. In silico carbon molecular beam epitaxial growth of graphene on the h-BN substrate: carbon source effect on van der Waals epitaxy

    NASA Astrophysics Data System (ADS)

    Lee, Jonghoon; Varshney, Vikas; Park, Jeongho; Farmer, Barry L.; Roy, Ajit K.

    2016-05-01

    Against the presumption that hexagonal boron-nitride (h-BN) should provide an ideal substrate for van der Waals (vdW) epitaxy to grow high quality graphene films, carbon molecular beam epitaxy (CMBE) techniques using solid carbon sublimation have reported relatively poor quality of the graphene. In this article, the CMBE growth of graphene on the h-BN substrate is numerically studied in order to identify the effect of the carbon source on the quality of the graphene film. The carbon molecular beam generated by the sublimation of solid carbon source materials such as graphite and glassy carbon is mostly composed of atomic carbon, carbon dimers and carbon trimers. Therefore, the graphene film growth becomes a complex process involving various deposition characteristics of a multitude of carbon entities. Based on the study of surface adsorption and film growth characteristics of these three major carbon entities comprising graphite vapour, we report that carbon trimers convey strong traits of vdW epitaxy prone to high quality graphene growth, while atomic carbon deposition is a surface-reaction limited process accompanied by strong chemisorption. The vdW epitaxial behaviour of carbon trimers is found to be substantial enough to nucleate and develop into graphene like planar films within a nanosecond of high flux growth simulation, while reactive atomic carbons tend to impair the structural integrity of the crystalline h-BN substrate upon deposition to form an amorphous interface between the substrate and the growing carbon film. The content of reactive atomic carbons in the molecular beam is suspected to be the primary cause of low quality graphene reported in the literature. A possible optimization of the molecular beam composition towards the synthesis of better quality graphene films is suggested.Against the presumption that hexagonal boron-nitride (h-BN) should provide an ideal substrate for van der Waals (vdW) epitaxy to grow high quality graphene films, carbon

  9. Enhanced magnetorheological performance of highly uniform magnetic carbon nanoparticles

    NASA Astrophysics Data System (ADS)

    Lee, Seungae; Shin, Keun-Young; Jang, Jyongsik

    2015-05-01

    Magnetic carbon nanoparticles (MC NPs) are prepared on a multi-gram scale through carbonization of iron-doped polypyrrole nanoparticles (PPy NPs). Three different-sized MC NPs (ca. 40, 60 and 90 nm) are prepared and adopted as dispersing materials for magnetorheological (MR) fluids to investigate the influence of particle size on MR properties. The MC NP-based MR fluids exhibit outstanding MR performances compared to the conventional magnetic carbon material-based fluids. In addition, the MR activities are enhanced with decreasing particle diameter and increasing applied magnetic field strength. Furthermore, anti-sedimentation properties are examined in order to achieve in-depth insight into the effect of the particle size on MR fluids.Magnetic carbon nanoparticles (MC NPs) are prepared on a multi-gram scale through carbonization of iron-doped polypyrrole nanoparticles (PPy NPs). Three different-sized MC NPs (ca. 40, 60 and 90 nm) are prepared and adopted as dispersing materials for magnetorheological (MR) fluids to investigate the influence of particle size on MR properties. The MC NP-based MR fluids exhibit outstanding MR performances compared to the conventional magnetic carbon material-based fluids. In addition, the MR activities are enhanced with decreasing particle diameter and increasing applied magnetic field strength. Furthermore, anti-sedimentation properties are examined in order to achieve in-depth insight into the effect of the particle size on MR fluids. Electronic supplementary information (ESI) available: The reaction mechanism at each step, and high-resolution TEM and SAED pattern analysis. See DOI: 10.1039/c4nr07168a

  10. Correlation between cell death and induction of non-rejoining PCC breaks by carbon-ion beams

    NASA Astrophysics Data System (ADS)

    Suzuki, M.; Kase, Y.; Kanai, T.; Ando, K.

    We have shown a correlation between cell death and induction of non-rejoining chromatin breaks in two normal human cells and three human tumor cell lines irradiated by carbon-ion beams and X rays. Non-rejoining chromatin breaks were measured by counting the number of remaining chromatin fragments detected by the premature chromosome condensation (PCC) technique. Carbon-ion beams were accelerated by the Heavy Ion Medical Accelerator in Chiba (HIMAC). The cells were irradiated by two different mono-LET beams (LET = 13 keV/mum and 77 keV/mum) and 200kV X rays. The RBE values of cell death for carbon-ion beams relative to X rays were 1.1 to 1.4 for 13 keV/mum beams and 2.5 to 2.9 for 77 keV/mum beams. The induction rate of non-rejoining PCC breaks per cell per Gy was found to be highest for the 77 keV/mum beams for all of the cell lines. The results found in this study show that there is a good correlation between cell death and induction of non-rejoining PCC breaks for these human cell lines.

  11. Correlation between cell death and induction of non-rejoining PCC breaks by carbon-ion beams.

    PubMed

    Suzuki, M; Kase, Y; Kanai, T; Ando, K

    1998-01-01

    We have shown a correlation between cell death and induction of non-rejoining chromatin breaks in two normal human cells and three human tumor cell lines irradiated by carbon-ion beams and X rays. Non-rejoining chromatin breaks were measured by counting the number of remaining chromatin fragments detected by the premature chromosome condensation (PCC) technique. Carbon-ion beams were accelerated by the Heavy Ion Medical Accelerator in Chiba (HIMAC). The cells were irradiated by two different mono-LET beams (LET = 13 keV/micrometer and 77 keV/micrometer ) and 200 kV X rays. The RBE values of cell death for carbon-ion beams relative to X rays were 1.1 to 1.4 for 13 keV/micrometer beams and 2.5 to 2.9 for 77 keV/micrometer beams. The induction rate of non-rejoining PCC breaks per cell per Gy was found to be highest for the 77 keV/micrometer beams for all of the cell lines. The results found in this study show that there is a good correlation between cell death and induction of non-rejoining PCC breaks for these human cell lines. PMID:11542786

  12. Optimizing 50kV hydrogen diagnostic neutral beam performance for active spectroscopy in MST

    NASA Astrophysics Data System (ADS)

    Feng, X.; Boguski, J.; Craig, D.; den Hartog, D. J.; Munaretto, S.; Nornberg, M. D.; Olivia, S.

    2015-11-01

    The 50 kV hydrogen diagnostic neutral beam on MST provides local measurements of impurity ion emission through charge exchange recombination spectroscopy (CHERS) and of core-localized magnetic field through the motional Stark effect (MSE). The beam, which was designed to provide 5A of neutral current at 50 kV to meet these needs, is currently on a test stand to accommodate diagnosis, in order to increase the reliability of beam formation, sustain a steady current of 5 amps for 20ms, and optimize the primary energy fraction. The reliability of arc formation was increased from 40% to 80% success rate with increase of cathode gas pressure from 150kPa to 200kPa, and the stability of the arc current is improved with a decrease of the insulation magnetic field. A calorimeter with 5 thermocouples is installed to measure the horizontal and vertical beam profiles as well as beam divergence. Beam energy components are quantified through Doppler-shift spectroscopy. Preliminary simulation results of the beam using the ALCBEAM code as well as a description of how changes to the beam performance can affect CHERS and MSE measurements are presented. This work is supported by the U.S. DOE.

  13. Approaching maximal performance of longitudinal beam compression in induction accelerator drivers

    SciTech Connect

    Mark, J.W.K.; Ho, D.D.M.; Brandon, S.T.; Chang, C.L.; Drobot, A.T.; Faltens, A.; Lee, E.P.; Krafft, G.A.

    1986-05-27

    Longitudinal beam compression is an integral part of the US induction accelerator development effort for heavy ion fusion. Producing maximal performance for key accelerator components is an essential element of the effort to reduce driver costs. We outline here initial studies directed towards defining the limits of final beam compression including considerations such as: maximal available compression, effects of longitudinal dispersion and beam emittance, combining pulse-shaping with beam compression to reduce the total number of beam manipulations, etc. The use of higher ion charge state Z greater than or equal to 3 is likely to test the limits of the previously envisaged beam compression and final focus hardware. A more conservative approach is to use additional beamlets in final compression and focus. On the other end of the spectrum of choices, alternate approaches might consider new final focus with greater tolerances for systematic momentum and current variations. Development of such final focus concepts would also allow more compact (and hopefully cheaper) hardware packages where the previously separate processes of beam compression, pulse-shaping and final focus occur as partially combined and nearly concurrent beam manipulations.

  14. Investigation of beamed-energy ERH thruster performance

    NASA Technical Reports Server (NTRS)

    Myrabo, Leik N.; Strayer, T. Darton; Bossard, John A.; Richard, Jacques C.; Gallimore, Alec D.

    1986-01-01

    The objective of this study was to determine the performance of an External Radiation Heated (ERH) thruster. In this thruster, high intensity laser energy is focused to ignite either a Laser Supported Combustion (LSC) wave or a Laser Supported Detonation (LSD) wave. Thrust is generated as the LSC or LSD wave propagates over the thruster's surface, or in the proposed thruster configuration, the vehicle afterbody. Thrust models for the LSC and LSD waves were developed and simulated on a computer. Performance parameters investigated include the effect of laser intensity, flight Mach number, and altitude on mean-thrust and coupling coefficient of the ERH thruster. Results from these models suggest that the ERH thruster using LSC/LSD wave ignition could provide propulsion performance considerably greater than any propulsion system currently available.

  15. Structure and properties of titanium surface layers after electron beam alloying with powder mixtures containing carbon

    NASA Astrophysics Data System (ADS)

    Lenivtseva, O. G.; Bataev, I. A.; Golkovskii, M. G.; Bataev, A. A.; Samoilenko, V. V.; Plotnikova, N. V.

    2015-11-01

    The structure and tribological properties of commercially pure titanium (cp-Ti) samples after non-vacuum electron beam surface alloying with carbon were studied. Two types of powders were used to introduce carbon in surface layer of cp-Ti: titanium carbide (TiC) and mixture of pure titanium and graphite ("Ti + C"). Single layer and multilayer coatings were studied. Application of electron beam for alloying provided cladding rate of 4.5 m2/h. The thickness of the clad coatings was 1.6-2.0 mm. The main phases received after "Ti + C" powder cladding were α-titanium, TiC, and retained graphite. In the samples obtained by cladding of TiC, graphite was not observed. A factor determining the microhardness and tribological properties of the cladded layer was the volume fraction of TiC. Maximum coating microhardness of 8 GPa was obtained by cladding of single layer of TiC powder or two layers of the "Ti + C" mixture. Two types of tests were carried out to evaluate the wear resistance of the samples. In friction tests against loose abrasive particles, the wear rate of the best samples was 9.3 times lower than that of cp-Ti. In wear tests using fixed abrasive particles, the relative wear resistance of the best samples was 2.3 times higher than that of cp-Ti.

  16. Physical properties of nitrogenated amorphous carbon films produced by ion-beam-assisted deposition

    NASA Astrophysics Data System (ADS)

    Rossi, Francois; Andre, Bernard; Veen, A. Van; Mijnarends, P. E.; Schut, H.; Labohm, F.; Delplancke, Marie Paule; Dunlop, Hugh; Anger, Eric

    1994-12-01

    Carbon films with up to 32 at.% N (a-C:N) have been prepared using an ion-beam-assisted magnetron, with an N2(+) beam at energies between 50 and 300 eV. The composition and density of the films vary strongly with the deposition parameters. Electron energy loss spectroscopy shows that these a-C:N films are mostly graphitic with up to 20% C Sp3 bonding. Rutherford backscattering spectroscopy and neutron depth profiling show that the density goes through a maximum as the average deposited energy per unit depth increases. X-ray photoelectron spectroscopy shows that nitrogen is mostly combined with carbon in triple (C(triple bond)N and double (C=N) bonds. Positron annihilation spectroscopy shows that the void concentration in the films goes through a minimum with deposited energy. These results are consistent with a densification induced by the collisions at low deposited energy, and damage-induced graphitization at high deposited energy values.

  17. Dual-ion-beam deposition of carbon films with diamond-like properties

    NASA Technical Reports Server (NTRS)

    Mirtich, M. J.; Swec, D. M.; Angus, J. C.

    1985-01-01

    A single and dual ion beam system was used to generate amorphous carbon films with diamond like properties. A methane/argon mixture at a molar ratio of 0.28 was ionized in the low pressure discharge chamber of a 30-cm-diameter ion source. A second ion source, 8 cm in diameter was used to direct a beam of 600 eV Argon ions on the substrates (fused silica or silicon) while the deposition from the 30-cm ion source was taking place. Nuclear reaction and combustion analysis indicate H/C ratios for the films to be 1.00. This high value of H/C, it is felt, allowed the films to have good transmittance. The films were impervious to reagents which dissolve graphitic and polymeric carbon structures. Although the measured density of the films was approximately 1.8 gm/cu cm, a value lower than diamond, the films exhibited other properties that were relatively close to diamond. These films were compared with diamond like films generated by sputtering a graphite target.

  18. High performance testbed for four-beam infrared interferometric nulling and exoplanet detection.

    PubMed

    Martin, Stefan; Booth, Andrew; Liewer, Kurt; Raouf, Nasrat; Loya, Frank; Tang, Hong

    2012-06-10

    Technology development for a space-based infrared nulling interferometer capable of earthlike exoplanet detection and characterization started in earnest in the last 10 years. At the Jet Propulsion Laboratory, the planet detection testbed was developed to demonstrate the principal components of the beam combiner train for a high performance four-beam nulling interferometer. Early in the development of the testbed, the importance of "instability noise" for nulling interferometer sensitivity was recognized, and the four-beam testbed would produce this noise, allowing investigation of methods for mitigating this noise source. The testbed contains the required features of a four-beam combiner for a space interferometer and performs at a level matching that needed for the space mission. This paper describes in detail the design, functions, and controls of the testbed. PMID:22695670

  19. Enhanced Performance Assessment System (EPAS) for carbon sequestration.

    SciTech Connect

    Wang, Yifeng; Sun, Amy Cha-Tien; McNeish, Jerry A.; Dewers, Thomas A.; Hadgu, Teklu; Jove-Colon, Carlos F.

    2010-09-01

    Carbon capture and sequestration (CCS) is an option to mitigate impacts of atmospheric carbon emission. Numerous factors are important in determining the overall effectiveness of long-term geologic storage of carbon, including leakage rates, volume of storage available, and system costs. Recent efforts have been made to apply an existing probabilistic performance assessment (PA) methodology developed for deep nuclear waste geologic repositories to evaluate the effectiveness of subsurface carbon storage (Viswanathan et al., 2008; Stauffer et al., 2009). However, to address the most pressing management, regulatory, and scientific concerns with subsurface carbon storage (CS), the existing PA methodology and tools must be enhanced and upgraded. For example, in the evaluation of a nuclear waste repository, a PA model is essentially a forward model that samples input parameters and runs multiple realizations to estimate future consequences and determine important parameters driving the system performance. In the CS evaluation, however, a PA model must be able to run both forward and inverse calculations to support optimization of CO{sub 2} injection and real-time site monitoring as an integral part of the system design and operation. The monitoring data must be continually fused into the PA model through model inversion and parameter estimation. Model calculations will in turn guide the design of optimal monitoring and carbon-injection strategies (e.g., in terms of monitoring techniques, locations, and time intervals). Under the support of Laboratory-Directed Research & Development (LDRD), a late-start LDRD project was initiated in June of Fiscal Year 2010 to explore the concept of an enhanced performance assessment system (EPAS) for carbon sequestration and storage. In spite of the tight time constraints, significant progress has been made on the project: (1) Following the general PA methodology, a preliminary Feature, Event, and Process (FEP) analysis was performed for

  20. Comparison of Biological Effectiveness of Carbon-Ion Beams in Japan and Germany

    SciTech Connect

    Uzawa, Akiko; Ando, Koichi Koike, Sachiko; Furusawa, Yoshiya; Matsumoto, Yoshitaka; Takai, Nobuhiko; Hirayama, Ryoichi; Watanabe, Masahiko; Scholz, Michael; Elsaesser, Thilo; Peschke, Peter

    2009-04-01

    Purpose: To compare the biological effectiveness of 290 MeV/amu carbon-ion beams in Chiba, Japan and in Darmstadt, Germany, given that different methods for beam delivery are used for each. Methods and Materials: Murine small intestine and human salivary gland tumor (HSG) cells exponentially growing in vitro were irradiated with 6-cm width of spread-out Bragg peaks (SOBPs) adjusted to achieve nearly identical beam depth-dose profiles at the Heavy-Ion Medical Accelerator in Chiba, and the SchwerIonen Synchrotron in Darmstadt. Cell kill efficiencies of carbon ions were measured by colony formation for HSG cells and jejunum crypts survival in mice. Cobalt-60 {gamma} rays were used as the reference radiation. Isoeffective doses at given survivals were used for relative biological effectiveness (RBE) calculations and interinstitutional comparisons. Results: Isoeffective D{sub 10} doses (mean {+-} standard deviation) of HSG cells ranged from 2.37 {+-} 0.14 Gy to 3.47 {+-} 0.19 Gy for Chiba and from 2.31 {+-} 0.11 Gy to 3.66 {+-} 0.17 Gy for Darmstadt. Isoeffective D{sub 10} doses of gut crypts after single doses ranged from 8.25 {+-} 0.17 Gy to 10.32 {+-} 0.14 Gy for Chiba and from 8.27 {+-} 0.10 Gy to 10.27 {+-} 0.27 Gy for Darmstadt, whereas isoeffective D{sub 30} doses after three fractionated doses were 9.89 {+-} 0.17 Gy through 13.70 {+-} 0.54 Gy and 10.14 {+-} 0.20 Gy through 13.30 {+-} 0.41 Gy for Chiba and Darmstadt, respectively. Overall difference of RBE between the two facilities was 0-5% or 3-7% for gut crypt survival or HSG cell kill, respectively. Conclusion: The carbon-ion beams at the National Institute of Radiological Sciences in Chiba, Japan and the Gesellschaft fuer Schwerionenforschung in Darmstadt, Germany are biologically identical after single and daily fractionated irradiation.

  1. Effects of evolving surface morphology on yield during focused ion beam milling of carbon.

    SciTech Connect

    Mayer, Thomas Michael; Adams, David Price; Archuleta, Kim M.; Vasile, Michael J.

    2005-07-01

    We investigate evolving surface morphology during focused ion beam bombardment of C and determine its effects on sputter yield over a large range of ion dose (10{sup 17}-10{sup 19} ions/cm{sup 2}) and incidence angles ({Theta} = 0-80{sup o}). Carbon bombarded by 20 keV Ga{sup +} either retains a smooth sputtered surface or develops one of two rough surface morphologies (sinusoidal ripples or steps/terraces) depending on the angle of ion incidence. For conditions that lead to smooth sputter-eroded surfaces there is no change in yield with ion dose after erosion of the solid commences. However, for all conditions that lead to surface roughening we observe coarsening of morphology with increased ion dose and a concomitant decrease in yield. A decrease in yield occurs as surface ripples increase wavelength and, for large {Theta}, as step/terrace morphologies evolve. The yield also decreases with dose as rippled surfaces transition to have steps and terraces at {Theta} = 75{sup o}. Similar trends of decreasing yield are found for H{sub 2}O-assisted focused ion beam milling. The effects of changing surface morphology on yield are explained by the varying incidence angles exposed to the high-energy beam.

  2. Performance of the H- Ion Source Supporting 1-MW Beam Operations at SNS

    NASA Astrophysics Data System (ADS)

    Han, B. X.; Hardek, T.; Kang, Y.; Murray, S. N.; Pennisi, T. R.; Piller, C.; Santana, M.; Welton, R. F.; Stockli, M. P.

    2011-09-01

    The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory reached 1-MW of beam power in September 2009, and now routinely operates near 1-MW for the production of neutrons. This paper reviews the performance, operational issues, implemented and planned mitigations of the SNS H- ion source to support such high power-level beams with high availability. Some results from R&D activities are also briefly described.

  3. Performance of the H{sup -} Ion Source Supporting 1-MW Beam Operations at SNS

    SciTech Connect

    Han, B. X.; Hardek, T.; Kang, Y.; Murray, S. N. Jr.; Pennisi, T. R.; Piller, C.; Santana, M.; Welton, R. F.; Stockli, M. P.

    2011-09-26

    The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory reached 1-MW of beam power in September 2009, and now routinely operates near 1-MW for the production of neutrons. This paper reviews the performance, operational issues, implemented and planned mitigations of the SNS H{sup -} ion source to support such high power-level beams with high availability. Some results from R and D activities are also briefly described.

  4. Performance of the H- Ion Source Supporting 1-MW Beam Operations at SNS

    SciTech Connect

    Han, Baoxi; Hardek, Thomas W; Kang, Yoon W; Murray Jr, S N; Pennisi, Terry R; Piller, Chip; Santana, Manuel; Welton, Robert F; Stockli, Martin P

    2011-01-01

    The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory reached 1-MW of beam power in September 2009, and now routinely operates near 1-MW for the production of neutrons. This paper reviews the performance, operational issues, implemented and planned mitigations of the SNS H- ion source to support such high power-level beams with high availability. Some results from R&D activities are also briefly described.

  5. {gamma}-Spectroscopy and Radioactive Beams: How To Perform Channel Selection ?

    SciTech Connect

    Rosse, B.; Redon, N.; Stezowski, O.; Schmitt, Ch.; Guinet, D.; Meyer, M.; Lautesse, Ph.; De France, G.; Bhattachasyya, S.; Mukherjee, G.

    2006-04-26

    An experiment has been performed using a SPIRAL 76Kr radioactive beam at GANIL to investigate rare-earth nuclei near the proton drip-line. The EXOGAM gamma array was coupled with the DIAMANT light charged-particle detector and the VAMOS spectrometer. We report here on the powerful of this setup to extract fusion-evaporation {gamma}-rays from a large beam contamination.

  6. Cost and performance of activated carbon injection for mercury control

    SciTech Connect

    2006-08-15

    Activated carbon injection (ACI) is one technology being developed to absorb mercury from mercury emitted from coal-fired power plants. In 2003/04, the USDOE and NETL selected 14 projects to test and evaluate mercury control technologies. While field testing is still ongoing, DOE/NETL recently completed an economic analysis of mercury control for six test sites spanning three ACI variations - conventional powdered activated carbon (PAC), brominated PAC and conventional PAC combined with a sorbent enhancement additive (SEA) applied to the coal. To evaluate the progress of the field testing program and discern the performance of ACI, a data adjustment methodology was developed to account for baseline methane capture. This data were used to perform economic analyses to achieve low, mid and high levels of mercury control. The costs are given in the article. Full details are available on the DOE/NETL website, www.netl.doe.gov. 2 figs., 1 photo.

  7. Effects of carbon ion beam irradiation on the shoot regeneration from in vitro axillary bud explants of the Impatiens hawkeri

    NASA Astrophysics Data System (ADS)

    Zhou, Libin; Zhou, Libin; Li, Wenjian; Li, Ping; Dong, Xicun; Qu, Ying; Ma, Shuang; Li, Qiang

    Accelerated ion beams is an excellent mutagen in plant breeding which can induce higher mutation frequencies and wider mutation spectrum than those of low linear energy transfer (LET) irradiations, such as X-rays (Okamura et al. 2003, Yamaguchi et al. 2003). Mutation breeding operation of two Saintpaulia ionahta cultivars using the method combining plant tissue culture technique and carbon ion beam irradiations were set out at Institute of Modern Physics from 2005 (Zhou et al. 2006). The effects of 960 MeV carbon ion beam and 8 MeV X-ray irradiations on regenerated shoots of Impatiens hawkeri from another kind of explants named in vitro axillary buds explants were studied recently. The biology endpoints in this study included relative number of roots (RNR), relative length of roots (RLR), relative height of shoots (RHS), relative number of nodes (RNN), survival fraction (SF) and morphology changes in the regenerated shoots. The experimental results showed that carbon ion beams inhibited the root and stem developments of axillary bud explants more severely than X-rays did. And the 50% lethal dose (LD50 ) is about 23.3 Gy for the carbon ion beam and 49.1 Gy for the X-rays, respectively. Relative biological effectiveness (RBE) of Impatiens hawkeri with respect to X-rays according to 50% SF was about two. Secondly, the percentage of shoots regenerated with malformed shoots including curliness, carnification, nicks in all Impatiens hawkeri axillary bud explants irradiated with carbon ion beam at 20 Gy accounted for 55.6%, while the highest number for the 40 Gy X-ray irradiation was 40%. Last, many regenerated shoots whose vascular bundle fused together were obtained only from explants irradiated with carbon ion beams. Based on the results above, it can be concluded that the effect of mutation induction by carbon ion beam irradiation on the axillary explants of Impatiens hawkeri is better than that by X-ray irradiation; and the optimal mutagenic dose varies from 20 Gy

  8. The emission carbonate crystallite and oxide cathode performance in electron tubes

    NASA Astrophysics Data System (ADS)

    Shafer, Don; Turnbull, John

    Emission from an oxide cathode is dependent upon the ratio of alkaline earth carbonates present at the cathodes surface. The method by which each carbonate is made plays a key role in its function in a cathode. Other factors effecting the performance of the oxide cathode are the type of constituents in the base metal. These constituents play key roles in barium diffusion and evaporation. It has been found that the crystalline structure of the alkaline earth carbonates affects the life of oxide cathode tubes. The rates of diffusion and evaporation of alkaline earth oxides, were studied with the use of the SEM-electron beam probe and energy dispersive X-ray Edax. Cathode surfaces to the depths of 1000 Å (approximately 200 atomic layers) were scanned. Many cathodes were studied after conversion from carbonates to oxides. It was found that barium oxide evaporated to 1/3 of the original formulation at oxide conversion. This diffusion and evaporation reaction took place throughout tube life. This work has shown that the crystal size, structure, and composition may be modified to lengthen the BaO half life and therefore lengthen the overall life of the electron tube.

  9. The influence of lateral beam profile modifications in scanned proton and carbon ion therapy: a Monte Carlo study

    NASA Astrophysics Data System (ADS)

    Parodi, K.; Mairani, A.; Brons, S.; Naumann, J.; Krämer, M.; Sommerer, F.; Haberer, T.

    2010-09-01

    Scanned ion beam delivery promises superior flexibility and accuracy for highly conformal tumour therapy in comparison to the usage of passive beam shaping systems. The attainable precision demands correct overlapping of the pencil-like beams which build up the entire dose distribution in the treatment field. In particular, improper dose application due to deviations of the lateral beam profiles from the nominal planning conditions must be prevented via appropriate beam monitoring in the beamline, prior to the entrance in the patient. To assess the necessary tolerance thresholds of the beam monitoring system at the Heidelberg Ion Beam Therapy Center, Germany, this study has investigated several worst-case scenarios for a sensitive treatment plan, namely scanned proton and carbon ion delivery to a small target volume at a shallow depth. Deviations from the nominal lateral beam profiles were simulated, which may occur because of misaligned elements or changes of the beam optic in the beamline. Data have been analysed with respect to the lateral penumbra, homogeneity and coverage of the dose deposition in the target volume. The results indicate that homogeneity is not seriously compromised by extremely narrow profiles for the standard planning choices of the lateral raster scan stepping and dose grid. Differently, broad beam distributions can significantly deteriorate the conformality of the dose delivery and too large increases (above ≈150-200% of the nominal spotsize) must be prevented.

  10. THE MEASURED PERFORMANCE OF A MILLIMETER WAVE BEAM SPLITTER

    SciTech Connect

    C.P. MOELLER; J. LOHR; J.L. DOANE

    2002-09-01

    An essential component of any high power transmission system is a directional coupler that provides a sample of the forward and reflected power when this power is being delivered to the intended load. In the case of millimeter power delivered through a highly oversized corrugated waveguide, there is the much more complex issue of mode purity. It is possible to design an effective mode selective branch guide directional coupler in smooth wall overmoded waveguide. In the typical highly overmoded corrugated waveguide propagating the HE{sub 11} mode, however, obtaining an adequate coupling factor can be difficult, and branch guide attenuation and phase velocity matching over several meters become concerns. A more practical approach for large diameter corrugated waveguide is to obtain a sample of the propagating beam at a miter bend mirror. At low power, the mirror could be a thin metal screen. At the megawatt level, however, heat removal must be considered. For example, at 110 GHz at 1 MW, taking the surface resistance of copper to be 0.10 {Omega}, the dissipation on a 45{sup o} copper mirror would be 750 W or 1500 W for H or E plane reflection, respectively. With a peak to average power ratio of 3.7 for the circular HE{sub 11} mode, in 31.75 cm diameter corrugated waveguide the peak dissipation can be as high as 500 W/cm{sup 2} at the center of the mirror. An edge cooled thin metal screen is not therefore practical, but a thick plate containing a single narrow channel, at the bottom of which is a row of holes in the remaining thin wall, can be adequately water-cooled on its face. To maintain vacuum and focus the radiation from the holes, the narrow channel is filled by a fused quartz plate, the shape of which is a 45{sup o} sector of a circle having a truncated apex at the coupling holes. These are being used as power monitors on the DIII-D ECH system and on other systems. Since this single row of holes samples only part of the wave field, however, interference among

  11. Analytic expressions for the inelastic scattering and energy loss of electron and proton beams in carbon nanotubes

    SciTech Connect

    Emfietzoglou, D.; Kyriakou, I.; Garcia-Molina, R.; Abril, I.; Kostarelos, K.

    2010-09-15

    We have determined ''effective'' Bethe coefficients and the mean excitation energy of stopping theory (I-value) for multiwalled carbon nanotubes (MWCNTs) and single-walled carbon nanotube (SWCNT) bundles based on a sum-rule constrained optical-data model energy loss function with improved asymptotic properties. Noticeable differences between MWCNTs, SWCNT bundles, and the three allotropes of carbon (diamond, graphite, glassy carbon) are found. By means of Bethe's asymptotic approximation, the inelastic scattering cross section, the electronic stopping power, and the average energy transfer to target electrons in a single inelastic collision, are calculated analytically for a broad range of electron and proton beam energies using realistic excitation parameters.

  12. Analytic expressions for the inelastic scattering and energy loss of electron and proton beams in carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Emfietzoglou, D.; Kyriakou, I.; Garcia-Molina, R.; Abril, I.; Kostarelos, K.

    2010-09-01

    We have determined "effective" Bethe coefficients and the mean excitation energy of stopping theory (I-value) for multiwalled carbon nanotubes (MWCNTs) and single-walled carbon nanotube (SWCNT) bundles based on a sum-rule constrained optical-data model energy loss function with improved asymptotic properties. Noticeable differences between MWCNTs, SWCNT bundles, and the three allotropes of carbon (diamond, graphite, glassy carbon) are found. By means of Bethe's asymptotic approximation, the inelastic scattering cross section, the electronic stopping power, and the average energy transfer to target electrons in a single inelastic collision, are calculated analytically for a broad range of electron and proton beam energies using realistic excitation parameters.

  13. Improvement of capacitive performances of symmetric carbon/carbon supercapacitors by addition of nanostructured polypyrrole powder

    NASA Astrophysics Data System (ADS)

    Benhaddad, L.; Gamby, J.; Makhloufi, L.; Pailleret, A.; Pillier, F.; Takenouti, H.

    2016-03-01

    A nanostructured polypyrrole powder was synthesized in a previous work from the oxidation of pyrrole by a nanostructured MnO2 powder used simultaneously as an oxidizing agent and a sacrificial template in a redox heterogeneous mechanism. In this study, this original PPy powder was used as an active additive material with different ratio in carbon/carbon symmetrical supercapacitors whose performances were studied by cyclic voltammetry and electrochemical impedance spectroscopy (EIS) using a Swagelok-type cell. From the EIS spectra, the complex capacitance was extracted using a model involving two Cole-Cole type complex capacitances linked in series. The specific capacitance values evaluated by EIS and cyclic voltammetry are in a good agreement between them. The results show that the addition of nanostructured polypyrrole powder improves significantly the specific capacitance of the carbon electrode and consequently the performances of carbon/carbon supercapacitors. The original and versatile synthesis method used to produce this polypyrrole powder appears to be attractive for large scale production of promising additives for electrode materials of supercapacitors.

  14. High performance hybrid slow positron beam and its user application spectrum

    NASA Astrophysics Data System (ADS)

    Waeber, W. B.; Shi, M.

    1997-05-01

    A true hybrid beam is operational at PSI. From a β+ radioisotope source and a premoderation of the positrons to medium energies in a high magnetic field confinement of Tesla order, a 3 keV wide spectrum of positrons is extracted and adiabatically guided to low fields of less than 100 G allowing extraction in a highly efficient and quasi-divergency-free way into field free space by increasing the positron's transverse energy spread by less than 20 eV. Double electrostatic focussing followed each time by W-remoderators (air lock anneal is possible) results in a beam diameter of μm dimensions. The microbeam is then transported through a cylindrical mirror beam switch device to five different user ports (one at a time, within minutes). The first target station is equipped with a retractable beam gun and a high precision sample manipulator with six movements for low (-200°C) and high (+950°C) temperatures (sample introduction by an air lock system). At the target chamber a UHV of 3.5 × 10 -11 mbar has been reached and the chamber can be equipped for surface physics experiments, for example to perform PAES. The sample is always at ground potential and the beam energy can be tuned between a few eV and 60 keV. The facility, initially equipped with a source of 500 mCi 58Co, produces a monoenergetic beam intensity (energy spread < 2 eV) at the target of 3 × 10 6 e +/s with an average transverse phase space corresponding to 100 μm × 50 mrad. In one of the user ports an optional 7 mm diameter beam of intensity 10 7 e +/s will be available. Initial beam experiments and possible applications will be discussed and the full potential of beam performance up-grade (intensity > 10 10e+/ s, pulsing, repolarization) will be outlined.

  15. Response of the FBX system to a carbon beam: its potential as a dosimeter in heavy particle radiotherapy.

    PubMed

    Semwal, M K; Banerjee, Milan; Sarma, Asiti; Vidyasagar, P B

    2002-06-21

    The FBX aqueous chemical dosimeter contains 0.2 mol m(-3) ferrous ammonium sulphate, 5.0 mol m(-3) benzoic acid and 0.20 mol m(-3) xylenol orange in 40.0 mol m(-3) sulphuric acid. The dosimeter can measure photon and electron doses in the range 0.1 to 3000 cGy in radiotherapy. The response of this dosimeter was measured for a 53.2 MeV carbon beam in the present work. Our initial result indicates that the sensitivity of the FBX system to the carbon beam as compared to cobalt-60 gamma rays is 25.5%, and thus we believe that the FBX system could be a useful dosimeter for carbon beams and similar heavy ions considered useful in radiotherapy. PMID:12118611

  16. Performance projections for laser beam power to space

    NASA Technical Reports Server (NTRS)

    Greenwood, Darryl P.

    1992-01-01

    We examine the requirements placed on an adaptive-optics system used to compensate atmospheric effects in propagating high-power lasers from ground to space. The particular application involves energy transfer from a ground station to a satellite. Our analysis explores performance associated with various beacon configurations, including satellite-based beacons, beacons in the lead-ahead direction, and synthetic beacons. Other system parameters are adjusted as well, including number of actuators in the deformable mirror and bandwidth of the servo system. We show that with an optimized system design it is possible to achieve collection efficiencies of 10-50 percent over zenith angles as great as 70 deg.

  17. Fabrication of carbon nanotube emitters on the graphite rod and their high field emission performance

    SciTech Connect

    Sun, Yuning; Hoon Shin, Dong; Nam Yun, Ki; Song, Yenan; Saito, Yahachi; Jin Lee, Cheol

    2014-01-27

    Carbon nanotube (CNT) emitters with small emission area were fabricated on graphite rods using CNT films. By introducing the edge polishing process, the field emission performance of the CNT emitter was much improved, which showed a very high emission current of 6.34 mA (1.6 A/cm{sup 2}) under an applied electric field of 5.3 V/μm. It also indicates good long-term emission stability, which reveals no degradation in the emission current for 20 h. The emission patterns demonstrate uniform and well-focused electron beam spots. The enhanced field emission performance is mainly attributed to the suppressed edge emission after the edge polishing process.

  18. Ion Beam Optimized Mechanical Characteristics of Glassy Polymeric Carbon for Medical Applications

    NASA Astrophysics Data System (ADS)

    Rodrigues, M. G.; da Cruz, N. C.; Rangel, E. C.; Zimmerman, R. L.; Ila, D.; Poker, D. B.; Hensley, D. K.

    2003-08-01

    Glassy Polymeric Carbon (GPC) has medical applications owing to its inertness and biocompatible characteristics. Commercial GPC prosthetics include mitral, aortic and hydrocephalic valves. Surface treatment of GPC increases the adhesion of endothelic tissue on GPC and avoids the occurrence of thrombus in cardiac implant. In this work, ion beam was used to improve the mechanical characteristics of GPC surface. Hardness was measured as a function of depth in precursor and GPC samples heat treated from 300 to 2500 °C before and after bombardment with energetic ions of silicon, carbon, oxygen and gold at energies of 5, 6, 8 and 10 MeV and fluences between 1.0×1013 and 1.0×1016 ions/cm2. Comparison shows that hardness increases of the bombarded samples depend on heat treatment temperature. We verify that ion bombardment promotes carbonization due to an increased linkage between the chains of the polymeric material in lateral groups that are more numerous for samples heat treated to 700 °C.

  19. Rapid phase-correlated rescanning irradiation improves treatment time in carbon-ion scanning beam treatment under irregular breathing

    NASA Astrophysics Data System (ADS)

    Mori, Shinichiro; Furukawa, Takuji

    2016-05-01

    To shorten treatment time in pencil beam scanning irradiation, we developed rapid phase-controlled rescanning (rPCR), which irradiates two or more isoenergy layers in a single gating window. Here, we evaluated carbon-ion beam dose distribution with rapid and conventional PCR (cPCR). 4 dimensional computed tomography (4DCT) imaging was performed on 12 subjects with lung or liver tumors. To compensate for intrafractional range variation, the field-specific target volume (FTV) was calculated using 4DCT within the gating window (T20–T80). We applied an amplitude-based gating strategy, in which the beam is on when the tumor is within the gating window defined by treatment planning. Dose distributions were calculated for layered phase-controlled rescanning under an irregular respiratory pattern, although a single 4DCT data set was used. The number of rescannings was eight times. The prescribed doses were 48 Gy(RBE)/1 fr (where RBE is relative biological effectiveness) delivered via four beam ports to the FTV for the lung cases and 45 Gy(RBE)/2 fr delivered via two beam ports to the FTV for the liver cases. In the liver cases, the accumulated dose distributions showed an increased magnitude of hot/cold spots with rPCR compared with cPCR. The results of the dose assessment metrics for the cPCR and rPCR were very similar. The D 95, D max, and D min values (cPCR/rPCR) averaged over all the patients were 96.3  ±  0.9%/96.0  ±  1.2%, 107.3  ±  3.6%/107.1  ±  2.9%, and 88.8  ±  3.2%/88.1  ±  3.1%, respectively. The treatment times in cPCR and rPCR were 110.7 s and 53.5 s, respectively. rPCR preserved dose conformation under irregular respiratory motion and reduced the total treatment time compared with cPCR.

  20. Rapid phase-correlated rescanning irradiation improves treatment time in carbon-ion scanning beam treatment under irregular breathing.

    PubMed

    Mori, Shinichiro; Furukawa, Takuji

    2016-05-21

    To shorten treatment time in pencil beam scanning irradiation, we developed rapid phase-controlled rescanning (rPCR), which irradiates two or more isoenergy layers in a single gating window. Here, we evaluated carbon-ion beam dose distribution with rapid and conventional PCR (cPCR). 4 dimensional computed tomography (4DCT) imaging was performed on 12 subjects with lung or liver tumors. To compensate for intrafractional range variation, the field-specific target volume (FTV) was calculated using 4DCT within the gating window (T20-T80). We applied an amplitude-based gating strategy, in which the beam is on when the tumor is within the gating window defined by treatment planning. Dose distributions were calculated for layered phase-controlled rescanning under an irregular respiratory pattern, although a single 4DCT data set was used. The number of rescannings was eight times. The prescribed doses were 48 Gy(RBE)/1 fr (where RBE is relative biological effectiveness) delivered via four beam ports to the FTV for the lung cases and 45 Gy(RBE)/2 fr delivered via two beam ports to the FTV for the liver cases. In the liver cases, the accumulated dose distributions showed an increased magnitude of hot/cold spots with rPCR compared with cPCR. The results of the dose assessment metrics for the cPCR and rPCR were very similar. The D 95, D max, and D min values (cPCR/rPCR) averaged over all the patients were 96.3  ±  0.9%/96.0  ±  1.2%, 107.3  ±  3.6%/107.1  ±  2.9%, and 88.8  ±  3.2%/88.1  ±  3.1%, respectively. The treatment times in cPCR and rPCR were 110.7 s and 53.5 s, respectively. rPCR preserved dose conformation under irregular respiratory motion and reduced the total treatment time compared with cPCR. PMID:27100312

  1. Robustness of target dose coverage to motion uncertainties for scanned carbon ion beam tracking therapy of moving tumors

    NASA Astrophysics Data System (ADS)

    Eley, John Gordon; Newhauser, Wayne David; Richter, Daniel; Lüchtenborg, Robert; Saito, Nami; Bert, Christoph

    2015-02-01

    Beam tracking with scanned carbon ion radiotherapy achieves highly conformal target dose by steering carbon pencil beams to follow moving tumors using real-time magnetic deflection and range modulation. The purpose of this study was to evaluate the robustness of target dose coverage from beam tracking in light of positional uncertainties of moving targets and beams. To accomplish this, we simulated beam tracking for moving targets in both water phantoms and a sample of lung cancer patients using a research treatment planning system. We modeled various deviations from perfect tracking that could arise due to uncertainty in organ motion and limited precision of a scanned ion beam tracking system. We also investigated the effects of interfractional changes in organ motion on target dose coverage by simulating a complete course of treatment using serial (weekly) 4DCTs from six lung cancer patients. For perfect tracking of moving targets, we found that target dose coverage was high ({{\\overline{V}}95} was 94.8% for phantoms and 94.3% for lung cancer patients, respectively) but sensitive to changes in the phase of respiration at the start of treatment and to the respiratory period. Phase delays in tracking the moving targets led to large degradation of target dose coverage (up to 22% drop for a 15° delay). Sensitivity to technical uncertainties in beam tracking delivery was minimal for a lung cancer case. However, interfractional changes in anatomy and organ motion led to large decreases in target dose coverage (target coverage dropped approximately 8% due to anatomy and motion changes after 1 week). Our findings provide a better understand of the importance of each of these uncertainties for beam tracking with scanned carbon ion therapy and can be used to inform the design of future scanned ion beam tracking systems.

  2. Robustness of target dose coverage to motion uncertainties for scanned carbon ion beam tracking therapy of moving tumors.

    PubMed

    Eley, John Gordon; Newhauser, Wayne David; Richter, Daniel; Lüchtenborg, Robert; Saito, Nami; Bert, Christoph

    2015-02-21

    Beam tracking with scanned carbon ion radiotherapy achieves highly conformal target dose by steering carbon pencil beams to follow moving tumors using real-time magnetic deflection and range modulation. The purpose of this study was to evaluate the robustness of target dose coverage from beam tracking in light of positional uncertainties of moving targets and beams. To accomplish this, we simulated beam tracking for moving targets in both water phantoms and a sample of lung cancer patients using a research treatment planning system. We modeled various deviations from perfect tracking that could arise due to uncertainty in organ motion and limited precision of a scanned ion beam tracking system. We also investigated the effects of interfractional changes in organ motion on target dose coverage by simulating a complete course of treatment using serial (weekly) 4DCTs from six lung cancer patients. For perfect tracking of moving targets, we found that target dose coverage was high ([Formula: see text] was 94.8% for phantoms and 94.3% for lung cancer patients, respectively) but sensitive to changes in the phase of respiration at the start of treatment and to the respiratory period. Phase delays in tracking the moving targets led to large degradation of target dose coverage (up to 22% drop for a 15° delay). Sensitivity to technical uncertainties in beam tracking delivery was minimal for a lung cancer case. However, interfractional changes in anatomy and organ motion led to large decreases in target dose coverage (target coverage dropped approximately 8% due to anatomy and motion changes after 1 week). Our findings provide a better understand of the importance of each of these uncertainties for beam tracking with scanned carbon ion therapy and can be used to inform the design of future scanned ion beam tracking systems. PMID:25650520

  3. Robustness of Target Dose Coverage to Motion Uncertainties for Scanned Carbon Ion Beam Tracking Therapy of Moving Tumors

    PubMed Central

    Eley, John Gordon; Newhauser, Wayne David; Richter, Daniel; Lüchtenborg, Robert; Saito, Nami; Bert, Christoph

    2015-01-01

    Beam tracking with scanned carbon ion radiotherapy achieves highly conformal target dose by steering carbon pencil beams to follow moving tumors using real-time magnetic deflection and range modulation. The purpose of this study was to evaluate the robustness of target dose coverage from beam tracking in light of positional uncertainties of moving targets and beams. To accomplish this, we simulated beam tracking for moving targets in both water phantoms and a sample of lung cancer patients using a research treatment planning system. We modeled various deviations from perfect tracking that could arise due to uncertainty in organ motion and limited precision of a scanned ion beam tracking system. We also investigated the effects of interfractional changes in organ motion on target dose coverage by simulating a complete course of treatment using serial (weekly) 4DCTs from 6 lung cancer patients. For perfect tracking of moving targets, we found that target dose coverage was high (V̄95 was 94.8% for phantoms and 94.3% for lung cancer patients, respectively) but sensitive to changes in the phase of respiration at the start of treatment and to the respiratory period. Phase delays in tracking the moving targets led to large degradation of target dose coverage (up to 22% drop for a 15 degree delay). Sensitivity to technical uncertainties in beam tracking delivery was minimal for a lung cancer case. However, interfractional changes in anatomy and organ motion led to large decreases in target dose coverage (target coverage dropped approximately 8% due to anatomy and motion changes after 1 week). Our findings provide a better understand of the importance of each of these uncertainties for beam tracking with scanned carbon ion therapy and can be used to inform the design of future scanned ion beam tracking systems. PMID:25650520

  4. Chemical investigations of isotope separation on line target units for carbon and nitrogen beams

    SciTech Connect

    Fraanberg, H.; Ammann, M.; Gaeggeler, H.W.; Koester, U.

    2006-03-15

    Radioactive ion beams (RIBs) are of significant interest in a number of applications. Isotope separation on line (ISOL) facilities provide RIB with high beam intensities and good beam quality. An atom that is produced within the ISOL target will first diffuse out from the target material. During the effusion towards the transfer line and into the ion source the many contacts with the surrounding surfaces may cause unacceptable delays in the transport and, hence, losses of the shorter-lived isotopes. We performed systematic chemical investigations of adsorption in a temperature and concentration regime relevant for ISOL targets and ion source units, with regard to CO{sub x} and NO{sub x} on Al{sub 2}O{sub 3} and SiO{sub 2}. These materials are potential construction materials for the above-mentioned areas. Off-line and on-line tests have been performed using a gas thermochromatography setup with radioactive tracers. The experiments were performed at the production of tracers for atmospheric chemistry (PROTRAC) facility at the Paul Scherrer Institute in Villigen, Switzerland.

  5. Beam tail effect of a performance-enhanced EC-ITC RF gun

    NASA Astrophysics Data System (ADS)

    Hu, Tong-Ning; Pei, Yuan-Ji; Qin, Bin; Chen, Qu-Shan

    2013-12-01

    The beam tail effect of multi-bunches will influence the electron beam performance in a high intensity thermionic RF gun. Beam dynamic calculations that illustrate the working states of single beam tail and multi-pulse feed-in of a performance-enhanced EC-ITC (external cathode independent tunable cavity) RF gun for an FEL (free electron laser) injector are performed to estimate the extracted bunch properties. By using both Parmela and homemade MATLAB codes, the effects of a single beam tail as well as interactions of multi-pulses are analyzed, where a ring-based electron algorithm is adopted to calculated RF fields and the space-charge field. Furthermore, the procedure of unexpected deviated-energy particles mixed with an effective bunch head is described by the MATLAB code as well. As a result, the performance-enhanced EC-ITC RF gun is proved to have the capability to extract continual stable bunches suitable for a high requirement THz-FEL.

  6. Performance of a scanning pencil-beam spaceborne scatterometer for ocean wind measurements

    NASA Technical Reports Server (NTRS)

    Moore, R. K.; Kennett, R. G.; Fuk, K.

    1988-01-01

    Simulation results show that a scatterometer design using two pencil beams scanning at different incidence angles measures the near-surface oceanic winds from a satellite better under most conditions than previous designs. The return signals from the ocean surface are much stronger than those from the fan beams used previously. Performance on a polar-orbiting satellite is compared with that of a fan beam spaceborne scatterometer. A wider and continuous swath is covered. The improvement in performance is higher at low wind speeds, so it is particularly suitable for measuring the low-mean-speed tropical wind fields. Performance on a low altitude tropic-orbiting platform such as the Space Station is also shown.

  7. High-resolution adaptive nulling performance for a lightweight agile EHF multiple beam antenna

    NASA Astrophysics Data System (ADS)

    Fenn, A. J.; Johnson, J. R.; Rispin, L. W.; Cummings, W. C.; Potts, B. M.

    The design and experimental performance of a lightweight high-resolution adaptive nulling extremely high-frequency multiple beam antenna (MBA) are addressed. A 127-beam MBA and a four-channel RF nulling network operating over the 43.5-to-45.5-GHz band were used to adaptively null a jammer in anechoic chamber measurements. Lightweight waveguide transmission lines together with ferrite switches were used to select beam ports from the 127-beam MBA. The MBA was designed to provide simultaneous coverage for three communications system users while providing pattern discrimination or nulling of jammers located within 0.1 deg of the user. Cancellation greater than 30 dB when operating in a wideband mode was experimentally demonstrated.

  8. Ultra stable carbon fiber high power CO2 laser with high quality laser beam and AOM implementation

    NASA Astrophysics Data System (ADS)

    Bohrer, Markus

    2015-03-01

    High security printing as well as ultra high precision engraving need laser resonators with very stable laser beams (600 - 800W) especially in combination with AOMs. Based upon a unique carbon fiber structure - stable within the sub-micrometer range - a new resonator has been developed, accompanied by most recent thermo-mechanical FEM calculations. The resulting beam is evaluated on an automated optical bench allowing to optimize the complete beam path with collimators and AOM. Synchronous on-line evaluation with PyroCams and thus knowledge about how to minimize distortions within the nonlinear elements is presented in this paper.

  9. High Performance Image Processing And Laser Beam Recording System

    NASA Astrophysics Data System (ADS)

    Fanelli, Anthony R.

    1980-09-01

    The article is meant to provide the digital image recording community with an overview of digital image processing, and recording. The Digital Interactive Image Processing System (DIIPS) was assembled by ESL for Air Force Systems Command under ROME AIR DEVELOPMENT CENTER's guidance. The system provides the capability of mensuration and exploitation of digital imagery with both mono and stereo digital images as inputs. This development provided for system design, basic hardware, software and operational procedures to enable the Air Force's System Command photo analyst to perform digital mensuration and exploitation of stereo digital images as inputs. The engineering model was based on state-of-the-art technology and to the extent possible off-the-shelf hardware and software. A LASER RECORDER was also developed for the DIIPS Systems and is known as the Ultra High Resolution Image Recorder (UHRIR). The UHRIR is a prototype model that will enable the Air Force Systems Command to record computer enhanced digital image data on photographic film at high resolution with geometric and radiometric distortion minimized.

  10. SU-E-T-470: Beam Performance of the Radiance 330 Proton Therapy System

    SciTech Connect

    Nazaryan, H; Nazaryan, V; Wang, F; Flanz, J; Alexandrov, V

    2014-06-01

    Purpose: The ProTom Radiance 330 proton radiotherapy system is a fully functional, compact proton radiotherapy system that provides advanced proton delivery capabilities. It supports three-dimensional beam scanning with energy and intensity modulation. A series of measurements have been conducted to characterize the beam performance of the first installation of the system at the McLaren Proton Therapy Center in Flint, Michigan. These measurements were part of the technical commissioning of the system. Select measurements and results are presented. Methods: The Radiance 330 proton beam energy range is 70–250 MeV for treatment, and up to 330 MeV for proton tomography and radiography. Its 3-D scanning capability, together with a small beam emittance and momentum spread, provides a highly efficient beam delivery. During the technical commissioning, treatment plans were created to deliver uniform maps at various energies to perform Gamma Index analysis. EBT3 Gafchromic films were irradiated using the Planned irradiation maps. Bragg Peak chamber was used to test the dynamic range during a scan in one layer for high (250 MeV) and Low (70 MeV) energies. The maximum and minimum range, range adjustment and modulation, distal dose falloff (80%–20%), pencil beam spot size, spot placement accuracy were also measured. The accuracy testing included acquiring images, image registration, receiving correction vectors and applying the corrections to the robotic patient positioner. Results: Gamma Index analysis of the Treatment Planning System (TPS) data vs. Measured data showed more than 90% of points within (3%, 3mm) for the maps created by the TPS. At Isocenter Beam Size (One sigma) < 3mm at highest energy (250 MeV) in air. Beam delivery was within 0.6 mm of the intended target at the entrance and the exit of the beam, through the phantom. Conclusion: The Radiance 330 Beam Performance Measurements have confirmed that the system operates as designed with excellent clinical

  11. Engineering heterojunctions with carbon nanostructures: towards high-performance optoelectronics

    NASA Astrophysics Data System (ADS)

    Wu, Judy Z.

    2015-08-01

    Low-dimensional carbon nanostructures such as nanotubes (CNTs) and graphene have excellent electronic, optoelectronic and mechanical properties, which provide fresh opportunities for designs of optoelectronic devices of extraordinary performance in addition to the benefits of low cost, large abundance, and light weight. This work investigates photodetectors made with CNTs and graphene with a particular focus on carbon-based nanohybrids aiming at a nanoscale control of photon absorption, exciton dissociation and charge transfer. Through several examples including graphene/GaSe-nanosheets, graphene/aligned ZnO nanorods, SWCNT/P3HT, and SWCNT/biomolecule, we show an atomic-scale control on the interfacial heterojunctions is the key to high responsivity and fast photoresponse in these nanohybrids optoelectronic devices.

  12. Electrochemical performance of Si anode modified with carbonized gelatin binder

    NASA Astrophysics Data System (ADS)

    Jiang, Ying; Mu, Daobin; Chen, Shi; Wu, Borong; Cheng, Kailin; Li, Luyu; Wu, Feng

    2016-09-01

    Gelatin is alternatively adopted as the binder to modify Si anode coupling with its carbonization treatment. The binder can provide good bonding and uniform dispersion of the particles besides its environmental benignancy. Importantly, the carbonized binder containing nitrogen will be advantageous to the electrical conductivity of the electrode. In addition, some spaces are formed in the electrode due to the decomposition and shrinkage of the gelatin binder during heat-treatment, which may facilitate electrolyte penetration and accommodate volume change during cycling. All these merits make contribution to the good electrochemical performance of the modified Si electrode. It exhibits a reversible capacity of 990.3 mA h g-1 after 70 cycles at a current density of 100 mA g-1 and 904 mA h g-1 after 100 cycles at 400 mA g-1.

  13. Performance of three pencil-type ionization chambers (10 cm) in computed tomography standard beams

    NASA Astrophysics Data System (ADS)

    de Castro, Maysa C.; Xavier, Marcos; Caldas, Linda V. E.

    2016-07-01

    The use of computed tomography (CT) has increased over the years, thus generating a concern about the doses received by patients undergoing this procedure. Therefore, it is necessary to perform routinely beam dosimetry with the use of a pencil-type ionization chamber. This detector is the most utilized in the procedures of quality control tests on this kind of equipment. The objective of this work was to perform some characterization tests in standard CT beams, as the saturation curve, polarity effect, ion collection efficiency and linearity of response, using three ionization chambers, one commercial and two developed at the IPEN.

  14. Shear deformable deformation of carbon nanotubes based on a new analytical nonlocal Timoshenko beam nodel

    SciTech Connect

    Zhang, Jianming; Yang, Yang

    2015-03-10

    According to Hamilton’s principle, a new mathematical model and analytical solutions for nonlocal Timoshenko beam model (ANT) is established based on nonlocal elastic continuum theory when shear deformation and nonlocal effect are considered. The new ANT equilibrium equations and boundary conditions are derived for bending analysis of carbon nanotubes (CNTs) with simply supported, clamped and cantilever. The ANT deflection solutions demonstrate that the CNT stiffness is enhanced by the presence of nonlocal stress effects. Furthermore, the new ANT model concluded verifiable bending behaviors for a cantilever CNT with point load at the free end, which depends on the strength of nonlocal stress. Therefore, this new model will gives a better prediction for mechanical behaviors of nanostructures.

  15. Enhancing capacitive deionization performance of electrospun activated carbon nanofibers by coupling with carbon nanotubes.

    PubMed

    Dong, Qiang; Wang, Gang; Wu, Tingting; Peng, Senpei; Qiu, Jieshan

    2015-05-15

    Capacitive deionization (CDI) is an alternative, effective and environmentally friendly technology for desalination of brackish water. The performance of the CDI device is highly determined by the electrode materials. In this paper, a composite of carbon nanotubes (CNTs) embedded in activated carbon nanofiber (ACF) was prepared by a direct co-electrospinning way and subsequent CO2 activation. The introduction of CNTs can greatly improve the conductivity while the CO2-mediated activation can render the final product with high porosity. As such, the hybrid structure can provide an excellent storage space and pathways for ion adsorption and conduction. When evaluated as electrode materials for CDI, the as-prepared CNT/ACF composites with higher electrical conductivity and mesopore ratios exhibited higher electrosorption capacity and good regeneration performance in comparison with the pure ACF. PMID:25595622

  16. The performance of heterodyne detection system for partially coherent beams in turbulent atmosphere

    NASA Astrophysics Data System (ADS)

    Chengqiang, Li; Tingfeng, Wang; Heyong, Zhang; Jingjiang, Xie; Lisheng, Liu; Shuai, Zhao; Jin, Guo

    2015-12-01

    The performance of heterodyne system is discussed for partially coherent beams in turbulent atmosphere by introducing turbulence spectrum of refractive-index fluctuations. Several analytic formulae for the heterodyne detection system using the partially coherent Gaussian Schell-model beam are presented. Based on Tatarskii spectrum model, some numerical results are given for the variation in the heterodyne efficiency with the misalignment angle, detector diameter, turbulence conditions, and parameters of the overlapping beams. According to the numerical results, we find that the turbulent atmosphere degrades the heterodyne efficiency significantly, and the variation in heterodyne efficiency is even slower against the misalignment angle in turbulence. For the deterministic received signal and the detector, the performance of the heterodyne detection can be adjusted by controlling the local oscillator signal parameters.

  17. Curative treatment of Stage I non-small-cell lung cancer with carbon ion beams using a hypofractionated regimen

    SciTech Connect

    Miyamoto, Tadaaki . E-mail: t_miyamt@nirs.go.jp; Baba, Masayuki; Yamamoto, Naoyoshi; Koto, Masashi; Sugawara, Toshiyuki; Yashiro, Tomoyasu; Kadono, Kennoshuke; Ezawa, Hidefumi; Tsujii, Hirohiko; Mizoe, Jun-Etsu; Yoshikawa, Kyosan; Kandatsu, Susumu; Fujisawa, Takehiko

    2007-03-01

    Purpose: A phase I/II study on carbon ion radiotherapy for Stage I non-small-cell lung cancer (NSCLC) was first conducted between 1994 and 1999 and determined the optimal dose. Second, a Phase II study using the optimal dose was performed. The purpose of the present study was to clarify the local control and 5-year survival rates. Methods and Materials: Between April 1999 and December 2000, 50 patients with 51 primary lesions were treated. Using a fixed dose of 72 GyE in nine fractions over 3 weeks, the primary tumors were irradiated with carbon ion beams alone. The average age of the patients was 74.5 years. Thirty-three (66%) of these were medically inoperable. Local control and survival were determined by using the Kaplan-Meier method and the data were statistically processed by using the log-rank test. Results: All patients were observed for a minimum of 5 years or until death with a median follow-up time of 59.2 months (range, 6.0-83.0 months). The local control rate for all patients was 94.7%. The patients' 5-year cause-specific survival rate was 75.7% (IA: 89.4; IB: 55.1), and overall survival 50.0% (IA: 55.2; IB: 42.9). No toxic reactions in the lung greater than Grade 3 were detected. Conclusions: Carbon ion radiotherapy, a new treatment modality with superior benefits in terms of quality of life and activity of daily living, has been proven as a valid alternative to surgery for Stage I NSCLC and to offer particular benefits, especially for elderly and inoperable patients.

  18. High performance ultracapacitors with carbon nanomaterials and ionic liquids

    DOEpatents

    Lu, Wen; Henry, Kent Douglas

    2012-10-09

    The present invention is directed to the use of carbon nanotubes and/or electrolyte structures in various electrochemical devices, such as ultracapacitors having an ionic liquid electrolyte. The carbon nanotubes are preferably aligned carbon nanotubes. Compared to randomly entangled carbon nanotubes, aligned carbon nanotubes can have better defined pore structures and higher specific surface areas.

  19. Crystalline magnetic carbon nanoparticle assisted photothermal delivery into cells using CW near-infrared laser beam

    PubMed Central

    Gu, Ling; Koymen, Ali R.; Mohanty, Samarendra K.

    2014-01-01

    Efficient and targeted delivery of impermeable exogenous material such as small molecules, proteins, and plasmids into cells in culture as well as in vivo is of great importance for drug, vaccine and gene delivery for different therapeutic strategies. Though advent of optoporation by ultrafast laser microbeam has allowed spatial targeting in cells, the requirement of high peak power to create holes on the cell membrane is not practical and also challenging in vivo. Here, we report development and use of uniquely non-reactive crystalline magnetic carbon nanoparticles (CMCNPs) for photothermal delivery (PTD) of impermeable dyes and plasmids encoding light-sensitive proteins into cells using low power continuous wave near-infrared (NIR) laser beam. Further, we utilized the magnetic nature of these CMCNPs to localize them in desired region by external magnetic field, thus minimizing the required number of nanoparticles. We discovered that irradiation of the CMCNPs near the desired cell(s) with NIR laser beam leads to temperature rise that not only stretch the cell-membrane to ease delivery, it also creates fluid flow to allow mobilization of exogenous substances to the delivery. Due to significant absorption properties of the CMCNPs in the NIR therapeutic window, PTD under in vivo condition is highly possible. PMID:24870227

  20. Crystalline magnetic carbon nanoparticle assisted photothermal delivery into cells using CW near-infrared laser beam

    NASA Astrophysics Data System (ADS)

    Gu, Ling; Koymen, Ali R.; Mohanty, Samarendra K.

    2014-05-01

    Efficient and targeted delivery of impermeable exogenous material such as small molecules, proteins, and plasmids into cells in culture as well as in vivo is of great importance for drug, vaccine and gene delivery for different therapeutic strategies. Though advent of optoporation by ultrafast laser microbeam has allowed spatial targeting in cells, the requirement of high peak power to create holes on the cell membrane is not practical and also challenging in vivo. Here, we report development and use of uniquely non-reactive crystalline magnetic carbon nanoparticles (CMCNPs) for photothermal delivery (PTD) of impermeable dyes and plasmids encoding light-sensitive proteins into cells using low power continuous wave near-infrared (NIR) laser beam. Further, we utilized the magnetic nature of these CMCNPs to localize them in desired region by external magnetic field, thus minimizing the required number of nanoparticles. We discovered that irradiation of the CMCNPs near the desired cell(s) with NIR laser beam leads to temperature rise that not only stretch the cell-membrane to ease delivery, it also creates fluid flow to allow mobilization of exogenous substances to the delivery. Due to significant absorption properties of the CMCNPs in the NIR therapeutic window, PTD under in vivo condition is highly possible.

  1. Nitrated carbon nanoblisters for high-performance glucose dehydrogenase bioanodes.

    PubMed

    de Souza, João C P; Iost, Rodrigo M; Crespilho, Frank N

    2016-03-15

    Recently, many strategies are being explored for efficiently wiring glucose dehydrogenase (GDh) enzymes capable of glucose (fuel) oxidation. For instance, the use of GDh NAD(+)-dependent for glucose oxidation is of great interest in biofuel cell technology because the enzyme are unaffected by the presence of molecular oxygen commonly present in electrolyte. Here we present the fabrication of flexible carbon fibers modified with nitrated carbon nanoblisters and their application as high-performance GDh bioanodes. These bioelectrodes could electro-oxidize glucose at -360 mV (vs. Ag/AgClsat) in the presence of a molecular oxygen saturated electrolyte with current densities higher than 1.0 mAcm(-2) at 0.0 V. It is corroborated by open circuit potential, where a potential stabilization occurs at -150 mV in a long term stability current-transient experiment. This value is in agreement with the quasi-steady current obtained at very low scan rate (0.1 mVs(-1)), where the onset potential for glucose oxidation is -180 mV. X-ray photoelectron spectroscopy and scanning electron microscopy revealed that the nitrated blisters and edge-like carbon structures, enabling highly efficient enzyme immobilization and low overpotential for electron transfer, allowing for glucose oxidation with potential values close to the thermodynamic cofactor. PMID:26516686

  2. Pumpkin-Derived Porous Carbon for Supercapacitors with High Performance.

    PubMed

    Bai, Suying; Tan, Guangqun; Li, Xiaoqin; Zhao, Qian; Meng, Yan; Wang, Yujue; Zhang, Yongzhi; Xiao, Dan

    2016-06-21

    Pumpkin has been employed for the first time as a renewable, low-cost precursor for the preparation of porous carbon materials with excellent performance. Unlike most other precursors, pumpkin is rich in sugars and starch, and it has advantageous properties for large-scale production. The as-prepared materials adopted a unique morphology that consisted of numerous fused sphere-like carbon grains with a high specific surface area (2968 m(2)  g(-1) ), abundant micro and mesopores, and excellent electrochemical properties. The pumpkin-derived activated carbon (PAC) material not only exhibited a high specific capacitance of 419 F g(-1) , but also showed considerable cycling stability, with 93.6 % retention after 10 000 cycles. Moreover, a symmetrical supercapacitor that was based on PAC showed a high energy density of 22.1 W h kg(-1) in aqueous electrolyte. These superior properties demonstrate that PAC holds great promise for applications in electrochemical energy-storage devices. PMID:27124360

  3. Preparation and electrochemical performance of ultra-short carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Wang, Xiao X.; Wang, Jian N.; Su, Lian F.

    Current carbon nanotubes (CNTs) are typically synthesized with micrometer lengths, low dispersion and low purity and thus oppose their applications in many fields. In this study, we make the first report on using a Fe compound (FeS) as a catalyst for controlling the length of CNTs to be less than 300 nm. This is achieved by dissolution of a proper proportion of ferrocene and thiophene in alcohol and pyrolysis of this solution at high temperature. Sulfur, resulting from the decomposition of thiophene, is shown to play key roles in promoting the growth of CNTs and limiting their length. The reason is suggested to be that FeS retards the dissociation of carbon source and diffusion of carbon in it as compared with pure Fe. Short CNTs from the present direct synthesis and from our previous solid-state cutting are used as an electrode material in Li-ion batteries and catalyst supports in fuel cells. Compared with conventional long CNTs, short CNTs show much better electrochemical performance. Due to the simplicity of the present synthetic technique, it may be used for mass production of short CNTs. Furthermore, the application of such a new material may be investigated in wide areas such as information technology, biomedicine, environmental and energy industries.

  4. Measurements of the performance of a beam condition monitor prototype in a 5 GeV electron beam

    NASA Astrophysics Data System (ADS)

    Hempel, M.; Afanaciev, K.; Burtowy, P.; Dabrowski, A.; Henschel, H.; Idzik, M.; Karacheban, O.; Lange, W.; Leonard, J.; Levy, I.; Lohmann, W.; Pollak, B.; Przyborowski, D.; Ryjov, V.; Schuwalow, S.; Stickland, D.; Walsh, R.; Zagozdzinska, A.

    2016-08-01

    The Fast Beam Conditions Monitor, BCM1F, in the Compact Muon Solenoid, CMS, experiment was operated since 2008 and delivered invaluable information on the machine induced background in the inner part of the CMS detector supporting a safe operation of the inner tracker and high quality data. Due to the shortening of the time between two bunch crossings from 50 ns to 25 ns and higher expected luminosity at the Large Hadron Collider, LHC, in 2015, BCM1F needed an upgrade to higher bandwidth. In addition, BCM1F is used as an on-line luminometer operated independently of CMS. To match these requirements, the number of single crystal diamond sensors was enhanced from 8 to 24. Each sensor is subdivided into two pads, leading to 48 readout channels. Dedicated fast front-end ASICs were developed in 130 nm technology, and the back-end electronics is completely upgraded. An assembled prototype BCM1F detector comprising sensors, a fast front-end ASIC and optical analog readout was studied in a 5 GeV electron beam at the DESY-II accelerator. Results on the performance are given.

  5. Performance of portable XRF and micro-XRF on carbonates

    NASA Astrophysics Data System (ADS)

    de Winter, Niels; Sinnesael, Matthias; Makarona, Christina; Claeys, Philippe

    2016-04-01

    Variations in elemental abundances in various carbonate archives offer a wealth of paleoenvironmental proxy information. State of the art portable handheld X-Ray Fluorescence (pXRF) and laboratory micro X-Ray Fluorescence (μXRF) instruments provide a relatively inexpensive and fast way of acquiring elemental composition data. However, there are well-known issues and limitations regarding the conversion of XRF spectral data into elemental concentrations. This study aims to offer a guideline for the appropriate use of these XRF techniques for the study of carbonates. Using a certified calcium carbonate standard, accuracy and reproducibility of both a pXRF (Bruker AXS Tracer IV) and a μXRF (Bruker M4 Tornado) instrument are tested under various measurement conditions. The experimental set-up allowed for the variation of several parameters, including measurement area, integration time, quantification method and filter use. The effects on the accuracy and reproducibility of the quantified elemental abundance results are examined in order to investigate under which conditions both devices perform best in determining trace element abundances in natural carbonates. The limits of detection and quantification are evaluated for both instruments for a range of commonly used trace elements (e.g. Sr, Mg, Zn, Fe …). The quality of the XRF spectra is evaluated using spectral processing software. Additionally, different methods of quantification are discussed. As a result, optimized parameter combinations are proposed for a range of commonly used elements. Finally, a comparison between the two X-Ray Fluorescence instruments allows the evaluation of their respective advantages and disadvantages and helps to determine which technique is best suited for a specific research question.

  6. Design and Near-Field Measurement Performance Evaluation of the Sea Winds Dual- Beam Reflector Antenna

    NASA Technical Reports Server (NTRS)

    Hussein, Z.; Rahmat-Samii, Y.; Kellogg, K.

    1997-01-01

    This paper presents the design and performance evaluation of a lightweight, composite material, elliptical-aperture, parabolic-reflector antenna. The performance characterization is obtained using the cylindrical near-field measurement facility at JPL as shown. The reflector has been designed and calibrated for the SeaWinds spaceborne scatterometer instrument. The instrument operates at Ku-band and is designed to accurately measure wind speed and direction over Earth's ocean surface. The SeaWinds antenna design requires two linearly polarized independent beams pointed at 40 deg.and 46 deg. from nadir as shown. The inner beam, pointed at 40 deg. from nadir, is horizontally polarized with 1.6 in x 1.8 in required beamwidths in the elevation and azimuth planes, respectively. The outer beam, pointed at 46 deg. from nadir, is vertically polarized with 1.4 in x 1.7 in required beamwidths. Noteworthy, the reflector boresight axis is pointed at 43 deg. from nadir. Both beams are required to have the first sidelobe level below -15 dB relative to the peak of the beam.

  7. Plasma and ion beam enhanced chemical vapour deposition of diamond and diamond-like carbon

    NASA Astrophysics Data System (ADS)

    Tang, Yongji

    WC-Co cutting tools are widely used in the machining industry. The application of diamond coatings on the surfaces of the tools would prolong the cutting lifetime and improves the manufacturing efficiency. However, direct chemical vapor deposition (CVD) of diamond coatings on WC-Co suffer from severe premature adhesion failure due to interfacial graphitization induced by the binder phase Co. In this research, a combination of hydrochloric acid (HCl) and hydrogen (H2) plasma pretreatments and a novel double interlayer of carbide forming element (CFE)/Al were developed to enhance diamond nucleation and adhesion. The results showed that both the pretreatments and interlayers were effective in forming continuous and adhesive nanocrystalline diamond coatings. The method is a promising replacement of the hazardous Murakami's regent currently used in WC-Co pretreatment with a more environmental friendly approach. Apart from coatings, diamond can be fabricated into other forms of nanostructures, such as nanotips. In this work, it was demonstrated that oriented diamond nanotip arrays can be fabricated by ion beam etching of as-grown CVD diamond. The orientation of diamond nanotips can be controlled by adjusting the direction of incident ion beam. This method overcomes the limits of other techniques in producing nanotip arrays on large areas with controlled orientation. Oriented diamond nano-tip arrays have been used to produce anisotropic frictional surface, which is successfully used in ultra-precision positioning systems. Diamond-like carbon (DLC) has many properties comparable to diamond. In this thesis, the preparation of alpha-C:H thin films by end-Hall (EH) ion source and the effects of ion energy and nitrogen doping on the microstructure and mechanical properties of the as-deposited thin films were investigated. The results have demonstrated that smooth and uniform alpha-C:H and alpha-C:H:N films with large area and reasonably high hardness and Young's modulus can be

  8. The Interaction of Functional and Dysfunctional Emotions during Balance Beam Performance

    ERIC Educational Resources Information Center

    Cottyn, Jorge; De Clercq, Dirk; Crombez, Geert; Lenoir, Matthieu

    2012-01-01

    The interaction between functional and dysfunctional emotions, as one of the major tenets of the Individual Zones of Optimal Functioning (IZOF) model (Hanin, 2000), was studied in a sport specific setting. Fourteen female gymnasts performed three attempts of a compulsory balance beam routine at three different heights. Heart rate and self-report…

  9. Increased Tensile Strength of Carbon Nanotube Yarns and Sheets through Chemical Modification and Electron Beam Irradiation

    NASA Technical Reports Server (NTRS)

    Miller, Sandi G.; Williams, Tiffany S.; Baker, James S.; Sola, Francisco; Lebron-Colon, Marisabel; McCorkle, Linda S.; Wilmoth, Nathan G.; Gaier, James; Chen, Michelle; Meador, Michael A.

    2014-01-01

    The inherent strength of individual carbon nanotubes offers considerable opportunity for the development of advanced, lightweight composite structures. Recent work in the fabrication and application of carbon nanotube (CNT) forms such as yarns and sheets has addressed early nanocomposite limitations with respect to nanotube dispersion and loading; and has pushed the technology toward structural composite applications. However, the high tensile strength of an individual CNT has not directly translated to macro-scale CNT forms where bulk material strength is limited by inter-tube electrostatic attraction and slippage. The focus of this work was to assess post processing of CNT sheet and yarn to improve the macro-scale strength of these material forms. Both small molecule functionalization and e-beam irradiation was evaluated as a means to enhance tensile strength and Youngs modulus of the bulk CNT material. Mechanical testing results revealed a tensile strength increase in CNT sheets by 57 when functionalized, while an additional 48 increase in tensile strength was observed when functionalized sheets were irradiated; compared to unfunctionalized sheets. Similarly, small molecule functionalization increased yarn tensile strength up to 25, whereas irradiation of the functionalized yarns pushed the tensile strength to 88 beyond that of the baseline yarn.

  10. One-dimensional carbon nanostructures for terahertz electron-beam radiation

    NASA Astrophysics Data System (ADS)

    Tantiwanichapan, Khwanchai; Swan, Anna K.; Paiella, Roberto

    2016-06-01

    One-dimensional carbon nanostructures such as nanotubes and nanoribbons can feature near-ballistic electronic transport over micron-scale distances even at room temperature. As a result, these materials provide a uniquely suited solid-state platform for radiation mechanisms that so far have been the exclusive domain of electron beams in vacuum. Here we consider the generation of terahertz light based on two such mechanisms, namely, the emission of cyclotronlike radiation in a sinusoidally corrugated nanowire (where periodic angular motion is produced by the mechanical corrugation rather than an externally applied magnetic field), and the Smith-Purcell effect in a rectilinear nanowire over a dielectric grating. In both cases, the radiation properties of the individual charge carriers are investigated via full-wave electrodynamic simulations, including dephasing effects caused by carrier collisions. The overall light output is then computed with a standard model of charge transport for two particularly suitable types of carbon nanostructures, i.e., zigzag graphene nanoribbons and armchair single-wall nanotubes. Relatively sharp emission peaks at geometrically tunable terahertz frequencies are obtained in each case. The corresponding output powers are experimentally accessible even with individual nanowires, and can be scaled to technologically significant levels using array configurations. These radiation mechanisms therefore represent a promising paradigm for light emission in condensed matter, which may find important applications in nanoelectronics and terahertz photonics.