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Sample records for incidence beam expander

  1. Grazing incidence beam expander

    Energy Technology Data Exchange (ETDEWEB)

    Akkapeddi, P.R.; Glenn, P.; Fuschetto, A.; Appert, Q.; Viswanathan, V.K.

    1985-01-01

    A Grazing Incidence Beam Expander (GIBE) telescope is being designed and fabricated to be used as an equivalent end mirror in a long laser resonator cavity. The design requirements for this GIBE flow down from a generic Free Electron Laser (FEL) resonator. The nature of the FEL gain volume (a thin, pencil-like, on-axis region) dictates that the output beam be very small. Such a thin beam with the high power levels characteristic of FELs would have to travel perhaps hundreds of meters or more before expanding enough to allow reflection from cooled mirrors. A GIBE, on the other hand, would allow placing these optics closer to the gain region and thus reduces the cavity lengths substantially. Results are presented relating to optical and mechanical design, alignment sensitivity analysis, radius of curvature analysis, laser cavity stability analysis of a linear stable concentric laser cavity with a GIBE. Fabrication details of the GIBE are also given.

  2. Adjustable magnification anamorphic beam expander

    Science.gov (United States)

    Escobar, S. R.

    1990-08-01

    A visible laser diode package is proposed to substitute a Krpton-Ion laser for alignment purposes. The proposed system uses 5 Melles Griot AR coated stock lenses. Tests performed to the optics reveal some undesirable properties, such as, astigmatism and spherical aberration; however, the interference pattern and star test reveals what seems to be a good quality wavefront. The interference fringes seem to be very good, but there still is a small presence of a comalike aberration at the fringes extreme. The star test revealed the system to be about 3 times diffraction limited. The system has yet to be tested in an alignment situation. As for now, it is ready to be tested with some minor alignment adjustments necessary for a good wavefront quality. A safety memo was written for testing the prototype system at the alignment lab. The initial laser diode system alignment method suggested, uses a reverse alignment procedure. In this procedure, the expected output (30 mm diameter beam) is input into the system output and alignment is performed by moving the components until the desired system input is found; an elliptical beam with 1 mm in the horizontal axis and 4 mm in the vertical axis. Once this reverse alignment procedure is completed the laser diode is placed at the system input. Fine alignment is done with the help of shear plate interference patterns in both, the 1 mm axis and 4 mm axis. The proposed final opto-mechanical packaging of this system is formed with squared adapter plates that are connected by means of four support rods where the center of the plate becomes the optical axis. These components are commercially available and provide high mechanical stability.

  3. Principles of the fifth order tuning of beam expanders

    International Nuclear Information System (INIS)

    Meot, F.; Aniel, T.

    1995-01-01

    An analytical treatment of the third and fifth order optics of beam expanders is described, which allows precise tuning of the optical elements of the beam line, and efficient optimization of the beam uniformizing at the extended target. An application to a two-dimensional expander is given as an illustration. (authors)

  4. Expanded beam (macro-imaging) ellipsometry

    International Nuclear Information System (INIS)

    Fried, M.; Juhasz, G.; Major, C.; Petrik, P.; Polgar, O.; Horvath, Z.; Nutsch, A.

    2011-01-01

    Our aim was to make possible to use spectroscopic ellipsometry for mapping purposes during one measuring cycle (minimum one rotation period of polarizer or analyzer) on many sample points. Our new technique uses non-collimated (non-parallel, mostly diffuse) illumination with an angle of incidence sensitive pinhole camera detector system and it works as an unusual kind of imaging ellipsometry. Adding multicolour supplemets, it provides spectral (a few wavelengths on a 2D image or a full spectrum along a line) information from rapid measurements of many points on a large (several dm2) area. This technique can be expanded by upscaling the geometry (upscaling the dimensions of the instrument, and characteristic imaging parameters such as focal lengths, distances, etc.). The lateral resolution is limited by the minimum resolved-angle determined by the detector system, mainly by the diameter of the pinhole. (The diameter of the pinhole is a compromise between the light intensity and the lateral resolution.) Small-aperture (25 mm diameter) polarizers are incorporated into both the polarization state generator (PSG) and polarization state detection (PSD) components of the instrument. The detection is almost without background because the pinhole serves as a filter against the scattered light. One rapid measuring cycle (less than 10 s) is enough to determine the polarization state at all the points inside the illuminated area. The collected data can be processed very fast (seconds) providing nearly real-time thicknesses and/or refractive index maps over many points of the sample surface even in the case of multilayer samples. The speed of the measuring system makes it suitable for using even on production lines. The necessary (in each sample-point different) angle-of-incidence and the mirror-effect calibration are made via well-known and optimized structures such as silicon/silicon-dioxide samples. The precision is suitable for detecting sub-nanometer thickness and a

  5. A beam expander facility for studying x-ray optics

    DEFF Research Database (Denmark)

    Christensen, Finn Erland; Hornstrup, Allan; Frederiksen, P.

    1992-01-01

    The detailed study of the performance of full scale x-ray optics often requires the illumination of large areas. This paper describes a beam expander facility at the Daresbury Synchrotron Radiation Facility. It combines monochromatization and beam expansion in one dimension. The beam expansion...... x-ray telescope will be studied, is described in detail. Review of Scientific Instruments is copyrighted by The American Institute of Physics....

  6. Frequency threshold for ion beam formation in expanding RF plasma

    Science.gov (United States)

    Chakraborty Thakur, Saikat; Harvey, Zane; Biloiu, Ioana; Hansen, Alex; Hardin, Robert; Przybysz, William; Scime, Earl

    2008-11-01

    We observe a threshold frequency for ion beam formation in expanding, low pressure, argon helicon plasma. Mutually consistent measurements of ion beam energy and density relative to the background ion density obtained with a retarding field energy analyzer and laser induced fluorescence indicate that a stable ion beam of 15 eV appears for source frequencies above 11.5 MHz. Reducing the frequency increases the upstream beam amplitude. Downstream of the expansion region, a clear ion beam is seen only for the higher frequencies. At lower frequencies, large electrostatic instabilities appear and an ion beam is not observed. The upstream plasma density increases sharply at the same threshold frequency that leads to the appearance of a stable double layer. The observations are consistent with the theoretical prediction that downstream electrons accelerated into the source by the double layer lead to increased ionization, thus balancing the higher loss rates upstream [1]. 1. M. A. Lieberman, C. Charles and R. W. Boswell, J. Phys. D: Appl. Phys. 39 (2006) 3294-3304

  7. Expanding options in radiation oncology: neutron beam therapy

    International Nuclear Information System (INIS)

    Cohen, L.

    1982-01-01

    Twelve years experience with neutron beam therapy in Britain, the USA, Europe and Japan shows that local control is achievable in late-stage epidermoid cancer somewhat more frequently than with conventional radiotherapy. Tumours reputed to be radioresistant (salivary gland, bladder, rectosigmoid, melanoma, bone and soft-tissue sarcomas) have proved to be particularly responsive to neutrons. Pilot studies in brain and pancreatic tumours suggest promising new approaches to management of cancer in these sites. The availability of neutron therapy in the clinical environment opens new prospects for irradiation of 'radioresistant' tumours, permits more conservative cancer surgery, expands the use of elective chemotherapy and provides a wider range of options for cancer patients. (author)

  8. Flexural Behaviour Of Reinforced Concrete Beams Containing Expanded Glass As Lightweight Aggregates

    Directory of Open Access Journals (Sweden)

    Khatib Jamal

    2015-12-01

    Full Text Available The flexural properties of reinforced concrete beams containing expanded glass as a partial fine aggregate (sand replacement are investigated. Four concrete mixes were employed to conduct this study. The fine aggregate was replaced with 0%, 25%, 50% and 100% (by volume expanded glass. The results suggest that the incorporation of 50% expanded glass increased the workability of the concrete. The compressive strength was decreasing linearly with the increasing amount of expanded glass. The ductility of the concrete beam significantly improved with the incorporation of the expanded glass. However, the load-carrying capacity of the beam and load at which the first crack occurs was reduced. It was concluded that the inclusion of expanded glass in structural concrete applications is feasible.

  9. Behavior of obliquely incident vector Bessel beams at planar interfaces

    KAUST Repository

    Salem, Mohamed

    2013-01-01

    We investigate the behavior of full-vector electromagnetic Bessel beams obliquely incident at an interface between two electrically different media. We employ a Fourier transform domain representation of Bessel beams to determine their behavior upon reflection and transmission. This transform, which is geometric in nature, consists of elliptical support curves with complex weighting associated with them. The behavior of the scattered field at an interface is highly complex, owing to its full-vector nature; nevertheless, this behavior has a straightforward representation in the transform domain geometry. The analysis shows that the reflected field forms a different vector Bessel beam, but in general, the transmitted field cannot be represented as a Bessel beam. Nevertheless, using this approach, we demonstrate a method to propagate a Bessel beam in the refractive medium by launching a non- Bessel beam at the interface. Several interesting phenomena related to the behavior of Bessel beams are illustrated, such as polarized reflection at Brewster\\'s angle incidence, and the Goos-Hänchen and Imbert-Federov shifts in the case of total reflection. © 2013 Optical Society of America.

  10. Expanding Beam Laser Amplifier as a Basic Architecture for Scaling High Power Lasers

    National Research Council Canada - National Science Library

    Jacob, Jonah

    1989-01-01

    In this report, the expanding beam laser (EBL) amplifier concept is presented as a method for efficient scaling of lasers to the multi-megawatt average power levels required for strategic applications...

  11. Sodern development of a high LIDT laser beam expander for ATLID

    Science.gov (United States)

    Battarel, Denis C.; Barnasson, Elodie

    2017-11-01

    Sodern has been contracted for the development of the laser beam expander used on the lidar of the ATLID instrument developed by Airbus Defence & Space France and Germany (Formerly ASTRIUM) embarked on the EathCARE satellite, element of the ESA (European Space Agency) Living Planet Programme. The ATLID emission beam expander (E-BEX) has two functions: one is to reduce the divergence of the laser in order to achieve a high spatial resolution and the other is to enlarge the laser beam to reduce the power density and thus reduce Laser Induced Contamination (LIC) and Laser Induced Damage Threshold (LIDT) effects on the outer surface exposed to vacuum. This paper exposes the design drivers of the beam expander which are: having optical components withstanding very high laser fluence at a wavelength of 355nm and exhibiting a very low depolarization ratio., hermetically sealing the cavity with metallic gaskets in order to keep the pressure constant so that beam collimation is not affected, choosing housing material compatible with both hermiticity requirements and thermal control. To obtain a high spatial resolution on Earth, ATLID requires a means for controlling beam collimation. This is ensured by an active thermal control on the beam expander in order to change its Wavefront Error (WFE) by a few tens of nanometers.

  12. Establishing the impact of temporary tissue expanders on electron and photon beam dose distributions.

    Science.gov (United States)

    Asena, A; Kairn, T; Crowe, S B; Trapp, J V

    2015-05-01

    This study investigates the effects of temporary tissue expanders (TTEs) on the dose distributions in breast cancer radiotherapy treatments under a variety of conditions. Using EBT2 radiochromic film, both electron and photon beam dose distribution measurements were made for different phantoms, and beam geometries. This was done to establish a more comprehensive understanding of the implant's perturbation effects under a wider variety of conditions. The magnetic disk present in a tissue expander causes a dose reduction of approximately 20% in a photon tangent treatment and 56% in electron boost fields immediately downstream of the implant. The effects of the silicon elastomer are also much more apparent in an electron beam than a photon beam. Evidently, each component of the TTE attenuates the radiation beam to different degrees. This study has demonstrated that the accuracy of photon and electron treatments of post-mastectomy patients is influenced by the presence of a tissue expander for various beam orientations. The impact of TTEs on dose distributions establishes the importance of an accurately modelled high-density implant in the treatment planning system for post-mastectomy patients. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  13. Dependance of sputtering yield on incident angle for ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Tanizaki, Hironori; Ooba, Hikaru; Masuhara, Kenichi

    1987-07-01

    The relationship between sputtering yeild (S/sub theta/) and the incident angle (theta) of an ion beam to some metals such as Fe, Ni, Zn and SUS304, was studied by Ion Micro Analyzer (IMA). It was confirmed that S/sub theta/ varied as a function of (costheta)/sup -f/. The value of f was differed with each sample, and ranged from 1.0 to 1.5 in this study. As theta increased, the surface roughness of the sputtered samples became greater, and the depth resolution of the depth profile became worse. It is necessary to pay attention to depth resolution, when various data concerning different incident angles are compared.

  14. Development of a raster electronics system for expanding the APT proton beam

    International Nuclear Information System (INIS)

    Chapelle, S.; Hubbard, E.L.; Smith, T.L.; Schulze, M.E.; Shafer, R.E.

    1998-01-01

    A 1700 MeV, 100 mA proton linear accelerator is being designed for Accelerator Production of Tritium (APT). A beam expansion system is required to uniformly irradiate a 19 x 190 cm tritium production target. This paper describes a beam expansion system consisting of eight ferrite dipole magnets to raster the beam in the x- and y-planes and also describes the salient features of the design of the electronics that are unique to the expander. Eight Insulated Gate Bipolar Transistor (IGBT)-based modulators drive the raster magnets with triangular current waveforms that are synchronized using phase-locked loops (PLLs) and voltage controlled crystal oscillators (VCXOs). Fault detection circuitry shuts down the beam before the target can be damaged by a failure of the raster system. Test data are presented for the prototype system

  15. Development of a raster electronics system for expanding the APT proton beam

    Energy Technology Data Exchange (ETDEWEB)

    Chapelle, S.; Hubbard, E.L.; Smith, T.L. [General Atomics, San Diego, CA (United States); Schulze, M.E.; Shafer, R.E. [General Atomics, Los Alamos, NM (United States)

    1998-12-31

    A 1700 MeV, 100 mA proton linear accelerator is being designed for Accelerator Production of Tritium (APT). A beam expansion system is required to uniformly irradiate a 19 x 190 cm tritium production target. This paper describes a beam expansion system consisting of eight ferrite dipole magnets to raster the beam in the x- and y-planes and also describes the salient features of the design of the electronics that are unique to the expander. Eight Insulated Gate Bipolar Transistor (IGBT)-based modulators drive the raster magnets with triangular current waveforms that are synchronized using phase-locked loops (PLLs) and voltage controlled crystal oscillators (VCXOs). Fault detection circuitry shuts down the beam before the target can be damaged by a failure of the raster system. Test data are presented for the prototype system.

  16. Characteristics of off-waist incident anomalous vortex beams in highly nonlocal media

    Directory of Open Access Journals (Sweden)

    Zhen-Feng Yang

    Full Text Available In this paper, we focus on the effect of the off-waist incident condition on the propagation characteristics of anomalous vortex beams (AVBs in nonlocal media. An expression is derived mathematically in order to describe the propagation dynamics of AVBs in nonlocal media under the off-waist incident condition. Typical propagation characteristics induced by the off-waist incident condition are illustrated numerically. It is found that the propagation characteristics under the off-waist incident condition are much different from those under the on-waist incident condition. Keywords: Off-waist incidence, Anomalous vortex beam, Nonlocal media

  17. Multiple scattering of a zero-order Bessel beam with arbitrary incidence by an aggregate of uniaxial anisotropic spheres

    International Nuclear Information System (INIS)

    Li, Z.J.; Wu, Z.S.; Qu, T.; Shang, Q.C.; Bai, L.

    2016-01-01

    Based on the generalized multiparticle Mie theory, multiple scattering of an aggregate of uniaxial anisotropic spheres illuminated by a zero-order Bessel beam (ZOBB) with arbitrary propagation direction is investigated. The particle size and configuration are arbitrary. The arbitrary incident Bessel beam is expanded in terms of spherical vector wave functions (SVWFs). Utilizing the vector addition theorem of SVWFs, interactive and total scattering coefficients are derived through the continuous boundary conditions on which the interaction of the particles is considered. The accuracy of the theory and codes are verified by comparing results with those obtained for arbitrary plane wave incidence by CST simulation, and for ZOBB incidence by a numerical method. The effects of angle of incidence, pseudo-polarization angle, half-conical angle, beam center position, and permittivity tensor elements on the radar cross sections (RCSs) of several types of collective uniaxial anisotropic spheres, such as a linear chain, a 4×4×4 cube-shaped array, and other periodical structures consisting of massive spheres, are numerically analyzed. Selected results on the properties of typical particles such as TiO 2 , SiO 2 , or other particle lattices are calculated. This investigation could provide an effective test for further research on the scattering characteristics of an aggregate of anisotropic spheres by a high-order Bessel vortex beam. The results have important application in optical tweezers and particle manipulation. - Highlights: • Scattering of Bessel beam by an aggregate of uniaxial anisotropic spheres is studied. • The zero-order Bessel beam propagates and polarizes along arbitrary direction. • The accuracy of expansion coefficients, the scattering theory and codes is verified. • Effects of various parameters on scattering properties are numerically discussed. • Scattering properties of several type of periodical array are numerically analyzed.

  18. An expander system of high stable laser beam for cesium atomic fountain clocks

    Science.gov (United States)

    Chen, Jiang; Lin, Rui; Liu, Dandan; Zhang, Hui; Ruan, Jun; Shi, Junru; Yu, Fengxiang; Zhang, Shougang

    2017-10-01

    The quality of the cold atoms sample plays an important role to improve the performance of cesium atomic fountain clocks. The preparation of cold atoms sample has a strict requirement for cooling lasers characteristics such as power stability, polarization, collimation, uniformity and verticality. This work implements a design of an expander system of high stable laser beam for the cold atom preparation. The cooling laser characteristics can be adjusted by the design, and the use of non-magnetic materials to avoid the magnetic field on the impact of cold atom. The cold atom sample with the number of 2×108 and temperature of 5μk was obtained by expander system. The result meets the requirements of the preparation of cold atoms for cesium atomic fountain clocks.

  19. Influence of laser beam incidence angle on laser lap welding quality of galvanized steels

    Science.gov (United States)

    Mei, Lifang; Yan, Dongbing; Chen, Genyu; Wang, Zhenhui; Chen, Shuixuan

    2017-11-01

    Based on the characteristics of laser welded structural parts of auto bodies, the influence of variation in laser beam incidence angle on the lap welding performance of galvanized auto-body sheets was studied. Lap welding tests were carried out on the galvanized sheets for auto-body application at different laser beam incidence angles by using the optimal welding parameters obtained through orthogonal experiment. The effects of incidence angle variation on seam appearance, cross-sectional shape, joint mechanical properties and microstructure of weldments were analyzed. In addition, the main factors influencing the value of incidence angle were investigated. According to the results, the weld seams had a good appearance as well as a fine, and uniform microstructure when the laser beam incidence angle was smaller than the critical incidence angle, and thus they could withstand great tensile and shear loads. Moreover, all tensile-shear specimens were fractured in the base material zone. When the laser beam incidence angle was larger than the critical incidence angle, defects like shrinkage and collapse tended to emerge, thereby resulting in the deteriorated weldability of specimens. Meanwhile, factors like the type and thickness of sheet, weld width as well as inter-sheet gap all had a certain effect on the value of laser beam incidence angle. When the sheet thickness was small and the weld width was narrow, the laser beam incidence angle could be increased appropriately. At the same time, small changes in the inter-sheet gap could greatly impact the value of incidence angle. When the inter-sheet gap was small, the laser beam incidence angle should not be too large.

  20. Incidence of Inborn Errors of Metabolism by Expanded Newborn Screening in a Mexican Hospital

    Directory of Open Access Journals (Sweden)

    Consuelo Cantú-Reyna MD

    2016-09-01

    Full Text Available Newborn screening for the detection of inborn errors of metabolism (IEM, endocrinopathies, hemoglobinopathies, and other disorders is a public health initiative aimed at identifying specific diseases in a timely manner. Mexico initiated newborn screening in 1973, but the national incidence of this group of diseases is unknown or uncertain due to the lack of large sample sizes of expanded newborn screening (ENS programs and lack of related publications. The incidence of a specific group of IEM, endocrinopathies, hemoglobinopathies, and other disorders in newborns was obtained from a Mexican hospital. These newborns were part of a comprehensive ENS program at Ginequito (a private hospital in Mexico, from January 2012 to August 2014. The retrospective study included the examination of 10 000 newborns’ results obtained from the ENS program (comprising the possible detection of more than 50 screened disorders. The findings were the following: 34 newborns were confirmed with an IEM, endocrinopathies, hemoglobinopathies, or other disorders and 68 were identified as carriers. Consequently, the estimated global incidence for those disorders was 3.4 in 1000 newborns; and the carrier prevalence was 6.8 in 1000. Moreover, a 0.04% false-positive rate was unveiled as soon as diagnostic testing revealed negative results. The most frequent diagnosis was glucose-6-phosphate dehydrogenase deficiency; and in the case of carriers, it was hemoglobinopathies. The benefit of the ENS is clear as it offers prompt treatment on the basis of an early diagnosis including proper genetic counseling. Furthermore, these results provide a good estimation of the frequencies of different forms of newborn IEM, endocrinopathies, hemoglobinopathies, and other disorders at Ginequito.

  1. The effects of laser beam incident angle and intensity distribution on Fabry-Perot etalon spectrum

    Science.gov (United States)

    Shen, Fahua; Wang, Yingying; Shi, Wenjuan; Chen, Ying; Liu, Mengling; Guo, Wenxin

    2017-11-01

    Fabry-Perot(F-P) etalon has important applications in laser detection, lidar and laser communication systems. In practical applications, the spectrum of the F-P etalon is affected by various factors, such as incident angle, divergence angle, spectral width, intensity distribution of the incident beam, absorption loss, surface defects of the plate and so on. The effects of the incident angle and the beam intensity distribution on F-P etalon spectrum are mainly analyzed. For the first time, taking into account both the beam incident angle and divergence angle, the precise analytical expression of the F-P etalon transmission spectrum is derived. For the Gaussian light intensity distribution, the precise analytical expression of the F-P etalon transmission spectrum is derived. The simulation analysis is carried out and the results are as follows. When the beam divergence angle is not zero, the incident angle increases, on the one hand, the center of the etalon spectrum is moved to the high frequency, and the frequency shift is linear with the square of the incident angle. The slope decreases with the increase of the divergence angle. On the other hand, resulting in peak reduction, spectral line broadening, and with the divergence angle increases, the more obvious the phenomenon. Considering the distribution of Gaussian light intensity, the spectrum of the etalon will be improved with the increase concentration of beam energy. On the one hand, the peak value is increased, the spectral line is narrowed and with the incidence angle increases, the degree of improvement is more obvious. On the one hand, the center of the spectrum moves toward the low frequency, but the larger the incident angle, the smaller the movement amount. The error of frequency discrimination or frequency locking by using the F-P etalon spectrum increases rapidly with the increase of the beam incident angle and beam divergence angle, and the Gaussian light intensity distribution beam can effectively

  2. Radio frequency source of a weakly expanding wedge-shaped xenon ion beam for contactless removal of large-sized space debris objects

    Science.gov (United States)

    Balashov, Victor; Cherkasova, Maria; Kruglov, Kirill; Kudriavtsev, Arseny; Masherov, Pavel; Mogulkin, Andrey; Obukhov, Vladimir; Riaby, Valentin; Svotina, Victoria

    2017-08-01

    A theoretical-experimental research has been carried out to determine the characteristics of a radio frequency (RF) ion source for the generation of a weakly expanding wedge-shaped xenon ion beam. Such ion beam geometry is of interest as a prototype of an on-board ion injector for contactless "ion shepherding" by service spacecraft to remove large space debris objects from geostationary orbits. The wedge shape of the ion beam increases its range. The device described herein comprises an inductive gas discharge chamber and a slit-type three-electrode ion extraction grid (IEG) unit. Calculations of accelerating cell geometries and ion trajectories determined the dependence of beam expansion half-angle on normalized perveance based on the measurements of the spatial distributions of the xenon plasma parameters at the IEG entrance for a xenon flow rate q ≈ 0.2 mg/s and an incident RF power Pin ≤ 250 W at a driving frequency f = 2 MHz. Experimental studies showed that the ion beam, circular at the IEG exit, accepted the elliptical form at the distance of 580 mm with half-angle of beam expansion across IEG slits about 2°-3° and close to 0° along them. Thus, the obtained result proved the possibility of creating a new-generation on-board ion injector that could be used in spacecrafts for removal of debris.

  3. On the determination of stress profiles in expanded austenite by grazing incidence X-ray diffraction and successive layer removal

    DEFF Research Database (Denmark)

    Fernandes, Frederico Augusto Pires; Christiansen, Thomas L.; Winther, Grethe

    2015-01-01

    Surface layers of expanded austenite resulting from nitriding typically exhibit large gradients in residual stress and composition. Evaluation of residual-stress profiles is explored by means of grazing incidence X-ray diffraction (GI-XRD), probing shallow depths, combined with successive layer...

  4. Recovering about 5 km of LHC Beam Vacuum System after Sector 3-4 Incident

    CERN Document Server

    Baglin, Vincent; Jenninger, Berthold; Jimenez, Jose; Mahner, Edgar; Schneider, Gerhard; Sinturel, Alexandre; Vidal, Alexis

    2010-01-01

    During the sec­tor 3-4 incident, the two apertures of the 3 km long cryogenic vacuum sectors of the CERN Large Hadron Collider (LHC) were brutally vented to helium. A systematic visual inspection of the beam pipe revealed the presence of soot, metallic debris and super insulation debris. After four month of cleaning, the beam vacuum system was recovered. This paper describes the tools and methodologies developed during this period, the achieved performances and discusses possible upgrades

  5. Expanded beam spectro-ellipsometry for big area on-line monitoring

    Science.gov (United States)

    Fried, M.; Major, C.; Juhasz, G.; Petrik, P.; Horvath, Z.

    2015-05-01

    Non-destructive analysing tools are needed at all stages of thin film process-development, especially photovoltaic (PV) development, and on production lines. In the case of thin films, layer thicknesses, micro-structure, composition, layer optical properties, and their uniformity are important parameters. An important focus is to express the dielectric functions of each component material in terms of a handful of wavelength independent parameters whose variation can cover all process variants of that material. With the resulting database, spectroscopic ellipsometry coupled with multilayer analysis can be developed for on-line point-by-point mapping and on-line line-by-line imaging. Off-line point-by-point mapping can be effective for characterization of non-uniformities in full scale PV panels or big area (even 450 mm diameter) Si-wafers in developing labs but it is slow in the on-line mode when only 15 points can be obtained (within 1 min) as a 120 cm long panel moves by the mapping station. Last years [M. Fried et al, Thin Solid Films 519, 2730 (2011)], a new instrumentation was developed that provides a line image of spectroscopic ellipsometry (wl=350- 1000 nm) data. Earlier a single 30 point line image could be collected in 10 s over a 15 cm width of PV material. Recent years we have built a 30, a 45 and a 60 cm width expanded beam ellipsometer which speed is increased by 10x. Now, 1800 points can be mapped in a 1 min traverse of a 60*120 cm PV panel or flexible roll-to-roll substrate.

  6. Large-angle production of charged pions with incident pion beams on nuclear targets

    CERN Document Server

    Apollonio, M.; Bagulya, A.; Barr, G.; Blondel, A.; Bobisut, F.; Bogomilov, M.; Bonesini, M.; Booth, C.; Borghi, S.; Bunyatov, S.; Burguet-Castell, J.; Catanesi, M.G.; Cervera-Villanueva, A.; Chimenti, P.; Coney, L.; Di Capua, E.; Dore, U.; Dumarchez, J.; Edgecock, R.; Ellis, M.; Ferri, F.; Gastaldi, U.; Giani, S.; Giannini, G.; Gibin, D.; Gilardoni, S.; Gorbunov, P.; Gossling, C.; Gomez-Cadenas, J.J.; Grant, A.; Graulich, J.S.; Gregoire, G.; Grichine, V.; Grossheim, A.; Guglielmi, A.; Howlett, L.; Ivanchenko, A.; Ivanchenko, V.; Kayis-Topaksu, A.; Kirsanov, M.; Kolev, D.; Krasnoperov, A.; Martin-Albo, J.; Meurer, C.; Mezzetto, M.; Mills, G.B.; Morone, M.C.; Novella, P.; Orestano, D.; Palladino, V.; Panman, J.; Papadopoulos, I.; Pastore, F.; Piperov, S.; Polukhina, N.; Popov, B.; Prior, G.; Radicioni, E.; Schmitz, D.; Schroeter, R.; Skoro, G.; Sorel, M.; Tcherniaev, E.; Temnikov, P.; Tereschenko, V.; Tonazzo, A.; Tortora, L.; Tsenov, R.; Tsukerman, I.; Vidal-Sitjes, G.; Wiebusch, C.; Zucchelli, P.

    2009-01-01

    Measurements of the double-differential pi+/- production cross-section in the range of momentum 100 MeV/c <= p <= 800 MeV/c and angle 0.35 rad <= theta <= 2.15 rad using pi+/- beams incident on beryllium, aluminium, carbon, copper, tin, tantalum and lead targets are presented. The data were taken with the large acceptance HARP detector in the T9 beam line of the CERN PS. The secondary pions were produced by beams in a momentum range from 3 GeV/c to 12.9 GeV/c hitting a solid target with a thickness of 5% of a nuclear interaction length. The tracking and identification of the produced particles was performed using a small-radius cylindrical time projection chamber (TPC) placed inside a solenoidal magnet. Incident particles were identified by an elaborate system of beam detectors. Results are obtained for the double-differential cross-sections d2sigma/dpdtheta at six incident beam momenta. Data at 3 GeV/c, 5 GeV/c, 8 GeV/c, and 12 GeV/c are available for all targets while additional data at 8.9 GeV/...

  7. Study on laser welding of austenitic stainless steel by varying incident angle of pulsed laser beam

    Science.gov (United States)

    Kumar, Nikhil; Mukherjee, Manidipto; Bandyopadhyay, Asish

    2017-09-01

    In the present work, AISI 304 stainless steel sheets are laser welded in butt joint configuration using a robotic control 600 W pulsed Nd:YAG laser system. The objective of the work is of twofold. Firstly, the study aims to find out the effect of incident angle on the weld pool geometry, microstructure and tensile property of the welded joints. Secondly, a set of experiments are conducted, according to response surface design, to investigate the effects of process parameters, namely, incident angle of laser beam, laser power and welding speed, on ultimate tensile strength by developing a second order polynomial equation. Study with three different incident angle of laser beam 89.7 deg, 85.5 deg and 83 deg has been presented in this work. It is observed that the weld pool geometry has been significantly altered with the deviation in incident angle. The weld pool shape at the top surface has been altered from semispherical or nearly spherical shape to tear drop shape with decrease in incident angle. Simultaneously, planer, fine columnar dendritic and coarse columnar dendritic structures have been observed at 89.7 deg, 85.5 deg and 83 deg incident angle respectively. Weld metals with 85.5 deg incident angle has higher fraction of carbide and δ-ferrite precipitation in the austenitic matrix compared to other weld conditions. Hence, weld metal of 85.5 deg incident angle achieved higher micro-hardness of ∼280 HV and tensile strength of 579.26 MPa followed by 89.7 deg and 83 deg incident angle welds. Furthermore, the predicted maximum value of ultimate tensile strength of 580.50 MPa has been achieved for 85.95 deg incident angle using the developed equation where other two optimum parameter settings have been obtained as laser power of 455.52 W and welding speed of 4.95 mm/s. This observation has been satisfactorily validated by three confirmatory tests.

  8. Large diameter permanent-magnets-expanded plasma source for spontaneous generation of low-energy ion beam.

    Science.gov (United States)

    Takahashi, Kazunori; Suzuki, Tatsuya; Ando, Akira

    2014-02-01

    Diameter of a permanent-magnets-expanded, radiofrequency (rf) plasma source is enlarged up to ∼13 cm for an application to a space propulsion device and tested with being attached to a diffusion chamber. The source is operated at 13.56 MHz 300 W rf power in low-pressure (40 mPa) argon. Measurement of ion energy distribution functions downstream of the source exit shows generation of a supersonic ion beam of about 20 eV. The detailed radial measurements demonstrate that the diameter and energy of the ion beam corresponds to the source tube diameter and the potential difference between the source and downstream plasmas, and that the radial profile of the beam flux is similar to the plasma density profile in the source cavity.

  9. Expanded studies of linear collider final focus systems at the Final Focus Test Beam

    Energy Technology Data Exchange (ETDEWEB)

    Tenenbaum, Peter Gregory [Stanford Univ., CA (United States)

    1995-12-01

    In order to meet their luminosity goals, linear colliders operating in the center-of-mass energy range from 3,50 to 1,500 GeV will need to deliver beams which are as small as a few Manometers tall, with x:y aspect ratios as large as 100. The Final Focus Test Beam (FFTB) is a prototype for the final focus demanded by these colliders: its purpose is to provide demagnification equivalent to those in the future linear collider, which corresponds to a focused spot size in the FFTB of 1.7 microns (horizontal) by 60 manometers (vertical). In order to achieve the desired spot sizes, the FFTB beam optics must be tuned to eliminate aberrations and other errors, and to ensure that the optics conform to the desired final conditions and the measured initial conditions of the beam. Using a combination of incoming-beam diagnostics. beam-based local diagnostics, and global tuning algorithms, the FFTB beam size has been reduced to a stable final size of 1.7 microns by 70 manometers. In addition, the chromatic properties of the FFTB have been studied using two techniques and found to be acceptable. Descriptions of the hardware and techniques used in these studies are presented, along with results and suggestions for future research.

  10. Expanded studies of linear collider final focus systems at the Final Focus Test Beam

    International Nuclear Information System (INIS)

    Tenenbaum, P.G.

    1995-12-01

    In order to meet their luminosity goals, linear colliders operating in the center-of-mass energy range from 3,50 to 1,500 GeV will need to deliver beams which are as small as a few Manometers tall, with x:y aspect ratios as large as 100. The Final Focus Test Beam (FFTB) is a prototype for the final focus demanded by these colliders: its purpose is to provide demagnification equivalent to those in the future linear collider, which corresponds to a focused spot size in the FFTB of 1.7 microns (horizontal) by 60 manometers (vertical). In order to achieve the desired spot sizes, the FFTB beam optics must be tuned to eliminate aberrations and other errors, and to ensure that the optics conform to the desired final conditions and the measured initial conditions of the beam. Using a combination of incoming-beam diagnostics. beam-based local diagnostics, and global tuning algorithms, the FFTB beam size has been reduced to a stable final size of 1.7 microns by 70 manometers. In addition, the chromatic properties of the FFTB have been studied using two techniques and found to be acceptable. Descriptions of the hardware and techniques used in these studies are presented, along with results and suggestions for future research

  11. Magnetic design and measurement of nonlinear multipole magnets for the APT beam expander system

    International Nuclear Information System (INIS)

    Barlow, D.B.; Shafer, R.E.; Martinez, R.P.; Walstrom, P.L.; Kahn, S.; Jain, A.; Wanderer, P.

    1997-01-01

    Two prototype nonlinear multipole magnets have been designed for use in the 800-MeV beam test of the APT beam-expansion concept at LANSCE. The iron-dominated magnets each consist of three independent coils, two for producing a predominantly octupole field with a tunable duodecapole component, and one for canceling the residual quadrupole field. Two such magnets, one for shaping each transverse plane, are required to produce a rectangular, uniform beam current density distribution with sharp edges on the APT target. This report will describe the magnetic design of these magnets, along with field measurements, and a comparison to the magnetic design

  12. Correction of Magnetic Optics and Beam Trajectory Using LOCO Based Algorithm with Expanded Experimental Data Sets

    Energy Technology Data Exchange (ETDEWEB)

    Romanov, A.; Edstrom, D.; Emanov, F. A.; Koop, I. A.; Perevedentsev, E. A.; Rogovsky, Yu. A.; Shwartz, D. B.; Valishev, A.

    2017-03-28

    Precise beam based measurement and correction of magnetic optics is essential for the successful operation of accelerators. The LOCO algorithm is a proven and reliable tool, which in some situations can be improved by using a broader class of experimental data. The standard data sets for LOCO include the closed orbit responses to dipole corrector variation, dispersion, and betatron tunes. This paper discusses the benefits from augmenting the data with four additional classes of experimental data: the beam shape measured with beam profile monitors; responses of closed orbit bumps to focusing field variations; betatron tune responses to focusing field variations; BPM-to-BPM betatron phase advances and beta functions in BPMs from turn-by-turn coordinates of kicked beam. All of the described features were implemented in the Sixdsimulation software that was used to correct the optics of the VEPP-2000 collider, the VEPP-5 injector booster ring, and the FAST linac.

  13. Beam test measurements on GaAs pixel detectors at various angles of incidence

    Energy Technology Data Exchange (ETDEWEB)

    Braunschweig, W.; Breibach, J.; Graessel, D.; Koenig, St.; Kubicki, Th.; Luebelsmeyer, K.; Rente, C.; Roeper, Ch.; Siedling, R.; Syben, O.; Tenbusch, F.; Toporowski, M.; Xiao, W.J

    1999-08-01

    A GaAs pixel detector constructed in Aachen has been tested in a 4 GeV electron beam at DESY. The experimental setup allowed tilting the detector with respect to the beam line with angles of incidence from 0 deg. to 45 deg. . The sensor-array consisted of 8 x 16 pixels with a size of 125 x 125{mu}m{sup 2} each. The detector was made of a 250{mu}m thick Freiberger SI-GaAs wafer. An improved contact was formed on the backside, allowing safe operation of the detector in the soft breakdown regime. A double metal technique allowed bonding the single pixels linearly to the readout-chip. Using the the fast PreMux128 preamplifier multiplexer chip ({tau}{sub p} = 40ns) a signal to noise ratio of 29 was obtained for a beam angle of incidence of 0 deg. increasing up to 38 for 45 deg. The spatial resolution obtained with an angle of incidence of 45 deg. was (9.0 {+-} 6.0){mu}m while the resolution of the untilted detector is equal to the digital one (36.1{mu}m). For these testbeam-measurements the detector was connected to the electronics via wire-bonds. For future experiments bump-bonding connections are required. The results of a process for the formation of bump-bond connections on GaAs pixeldetectors are shown.

  14. Technical Note: On the impact of the incident electron beam energy on the primary dose component of flattening filter free photon beams.

    Science.gov (United States)

    Kuess, Peter; Georg, Dietmar; Palmans, Hugo; Lechner, Wolfgang

    2016-08-01

    For commercially available linear accelerators (Linacs), the electron energies of flattening filter free (FFF) and flattened (FF) beams are either identical or the electron energy of the FFF beam is increased to match the percentage depth dose curve (PDD) of the FF beam (in reference geometry). This study focuses on the primary dose components of FFF beams for both kinds of settings, studied on the same Linac. The measurements were conducted on a VersaHD Linac (Elekta, Crawley, UK) for both FF and FFF beams with nominal energies of 6 and 10 MV. In the clinical setting of the VersaHD, the energy of FFFM (Matched) beams is set to match the PDDs of the FF beams. In contrast the incident electron beam of the FFFU beam was set to the same energy as for the FF beam. Half value layers (HVLs) and a dual parameter beam quality specifier (DPBQS) were determined. For the 6 MV FFFM beam, HVL and DPBQS values were very similar compared to those of the 6 MV FF beam, while for the 10 MV FFFM and FF beams, only %dd(10)x and HVL values were comparable (differences below 1.5%). This shows that matching the PDD at one depth does not guarantee other beam quality dependent parameters to be matched. For FFFU beams, all investigated beam quality specifiers were significantly different compared to those for FF beams of the same nominal accelerator potential. The DPBQS of the 6 MV FF and FFFM beams was equal within the measurement uncertainty and was comparable to published data of a machine with similar TPR20,10 and %dd(10)x. In contrast to that, the DPBQS's two parameters of the 10 MV FFFM beam were substantially higher compared to those for the 10 MV FF beam. PDD-matched FF and FFF beams of both nominal accelerator potentials were observed to have similar HVL values, indicating similarity of their primary dose components. Using the DPBQS revealed that the mean attenuation coefficient was found to be the same within the uncertainty of 0.8% for 6 MV FF and 6 MV FFFM beams, while for 10 MV

  15. Technical Note: On the impact of the incident electron beam energy on the primary dose component of flattening filter free photon beams

    International Nuclear Information System (INIS)

    Kuess, Peter; Georg, Dietmar; Lechner, Wolfgang; Palmans, Hugo

    2016-01-01

    Purpose: For commercially available linear accelerators (Linacs), the electron energies of flattening filter free (FFF) and flattened (FF) beams are either identical or the electron energy of the FFF beam is increased to match the percentage depth dose curve (PDD) of the FF beam (in reference geometry). This study focuses on the primary dose components of FFF beams for both kinds of settings, studied on the same Linac. Methods: The measurements were conducted on a VersaHD Linac (Elekta, Crawley, UK) for both FF and FFF beams with nominal energies of 6 and 10 MV. In the clinical setting of the VersaHD, the energy of FFF M (Matched) beams is set to match the PDDs of the FF beams. In contrast the incident electron beam of the FFF U beam was set to the same energy as for the FF beam. Half value layers (HVLs) and a dual parameter beam quality specifier (DPBQS) were determined. Results: For the 6 MV FFF M beam, HVL and DPBQS values were very similar compared to those of the 6 MV FF beam, while for the 10 MV FFF M and FF beams, only %dd(10) x and HVL values were comparable (differences below 1.5%). This shows that matching the PDD at one depth does not guarantee other beam quality dependent parameters to be matched. For FFF U beams, all investigated beam quality specifiers were significantly different compared to those for FF beams of the same nominal accelerator potential. The DPBQS of the 6 MV FF and FFF M beams was equal within the measurement uncertainty and was comparable to published data of a machine with similar TPR 20,10 and %dd(10) x . In contrast to that, the DPBQS’s two parameters of the 10 MV FFF M beam were substantially higher compared to those for the 10 MV FF beam. Conclusions: PDD-matched FF and FFF beams of both nominal accelerator potentials were observed to have similar HVL values, indicating similarity of their primary dose components. Using the DPBQS revealed that the mean attenuation coefficient was found to be the same within the uncertainty of

  16. Optimum solution of dual-ring double-scattering system for an incident beam with given phase space for proton beam spreading

    CERN Document Server

    Takada, Y

    2002-01-01

    A systematic method is given for deriving optimum scatterer parameters for the dual-ring double-scattering system for the incident proton beam with the given phase space parameters. This is accomplished by relating it to the known optimum solution for zero-emittance beam. Limitations on the phase space parameters of the beam incident on the first scatterer have been clarified to obtain such valid solutions. It is shown that the dual-ring double-scattering method can be applied to an incident beam with emittance as large as 100-200 pi mm mrad. The effect of the change of phase space parameters on the lateral distribution has been investigated. It was found that the larger the emittance of the beam, the more sensitive the fluence distribution is to the change of phase space parameters. The effect of the different emittances of the incident beam in x-theta, y-phi spaces is discussed. It is shown that lateral distribution is sensitive to the misalignment of the beam.

  17. Argon Beam Coagulator in Breast Surgery: Effect on the Incidence of Breast Seroma.

    Science.gov (United States)

    Lefemine, Valentina; Cornish, Julie A; Abou-Samra, Walid

    2011-12-01

    Although Argon Beam Coagulators (ABCs) are widely used in urological and gynecological procedures, there have been only two studies published so far on their use and benefits in breast surgery. This study compares the incidence of breast seroma following mastectomy upon the use of ABC versus standard monopolar diathermy. This is a retrospective cohort study, with data collected from January 2006 to August 2008 for all patients who underwent a simple mastectomy and axillary surgery. Outcomes included incidence of seroma, amount of drainage on day of discharge, and timing of seroma formation. Fifty-six patients were studied, with 30 undergoing simple mastectomy using ABC diathermy and 25 using simple diathermy. The incidence of postoperative breast seroma development was 30% (n = 9) in the former group and 36% (n = 9) in the latter. In the ABC group, a high postoperative drainage at discharge was predictive of developing a seroma; this was not observed in the monopolar group. The search for methods to reduce the incidence of seroma in breast surgery is ongoing worldwide. Despite a previous report, this study failed to show any significant difference between ABC and monopolar diathermy in the incidence of breast seroma formation following simple mastectomy and axillary surgery. ABC diathermy is more costly, and its use needs to be carefully considered in an era of a stretched National Health Service financial budget.

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

    International Nuclear Information System (INIS)

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

    1987-08-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1987-08-01

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

  20. Second crossover energy of insulating materials using stationary electron beam under normal incidence

    Energy Technology Data Exchange (ETDEWEB)

    Rau, E.I. [Institute of Microelectronics Technology of Russian Academy of Science, 142432 Chernogolovka, Moscow District (Russian Federation)], E-mail: rau@phys.msu.ru; Fakhfakh, S. [LaMaCop, Faculte des Sciences, Route Soukra km 3, BP 802, CP 3018 Sfax (Tunisia); Andrianov, M.V.; Evstafeva, E.N. [Institute of Microelectronics Technology of Russian Academy of Science, 142432 Chernogolovka, Moscow District (Russian Federation); Jbara, O. [UTAP/LASSI, EA 3802, Faculte des Sciences, BP 1039, 51687 Reims Cedex 2 (France)], E-mail: omar.jbara@univ-reims.fr; Rondot, S.; Mouze, D. [UTAP/LASSI, EA 3802, Faculte des Sciences, BP 1039, 51687 Reims Cedex 2 (France)

    2008-03-15

    The purpose of this paper is to give some aspects of charging effects on dielectric materials submitted to continuous electron beam irradiation in a scanning electron microscope (SEM). When the dielectric is irradiated continuously, the so-called total yield approach (TYA) used to predict the sign of the charge appeared on electron irradiated insulators fails because the charge accumulated in the dielectric interferes with the electrons emission processes. Based on previous experimental and theoretical works found in the literature, an analysis of the evolution of the electron yield curves {sigma} = f(E{sub 0}) of insulators during irradiation is given. The aim of this work is firstly to determine experimentally the second crossover energy E{sub 2C} under continuous electron irradiation (charging conditions) and secondly to demonstrate that the charge balance occurs at this beam energy and not at E{sub 2} the energy deduced from non-charging conditions (pulse primary electron beam experiments) as commonly asserted. It is however possible to apply the TYA by substituting the critical energy E{sub 2} for E{sub 2C}. The experimental procedure is based on simultaneous time dependent measurements of surface potential, leakage current and displacement current. The study underlines the difference between the landing energy of primary electrons E{sub L} at the steady state and the second crossover energy, E{sub 2C}, for charged samples. Some preliminary results are also obtained concerning the influence of the incident beam density on the energy E{sub 2C}. The samples used for this study are PMMA, polycrystalline silicone dioxide (p-SiO{sub 2}), polycrystalline alumina (p-Al{sub 2}O{sub 3}) and soda lime glass (SLG)

  1. Second crossover energy of insulating materials using stationary electron beam under normal incidence

    International Nuclear Information System (INIS)

    Rau, E.I.; Fakhfakh, S.; Andrianov, M.V.; Evstafeva, E.N.; Jbara, O.; Rondot, S.; Mouze, D.

    2008-01-01

    The purpose of this paper is to give some aspects of charging effects on dielectric materials submitted to continuous electron beam irradiation in a scanning electron microscope (SEM). When the dielectric is irradiated continuously, the so-called total yield approach (TYA) used to predict the sign of the charge appeared on electron irradiated insulators fails because the charge accumulated in the dielectric interferes with the electrons emission processes. Based on previous experimental and theoretical works found in the literature, an analysis of the evolution of the electron yield curves σ = f(E 0 ) of insulators during irradiation is given. The aim of this work is firstly to determine experimentally the second crossover energy E 2C under continuous electron irradiation (charging conditions) and secondly to demonstrate that the charge balance occurs at this beam energy and not at E 2 the energy deduced from non-charging conditions (pulse primary electron beam experiments) as commonly asserted. It is however possible to apply the TYA by substituting the critical energy E 2 for E 2C . The experimental procedure is based on simultaneous time dependent measurements of surface potential, leakage current and displacement current. The study underlines the difference between the landing energy of primary electrons E L at the steady state and the second crossover energy, E 2C , for charged samples. Some preliminary results are also obtained concerning the influence of the incident beam density on the energy E 2C . The samples used for this study are PMMA, polycrystalline silicone dioxide (p-SiO 2 ), polycrystalline alumina (p-Al 2 O 3 ) and soda lime glass (SLG)

  2. Compensation of errors due to incident beam drift in a 3 DOF measurement system for linear guide motion.

    Science.gov (United States)

    Hu, Pengcheng; Mao, Shuai; Tan, Jiu-Bin

    2015-11-02

    A measurement system with three degrees of freedom (3 DOF) that compensates for errors caused by incident beam drift is proposed. The system's measurement model (i.e. its mathematical foundation) is analyzed, and a measurement module (i.e. the designed orientation measurement unit) is developed and adopted to measure simultaneously straightness errors and the incident beam direction; thus, the errors due to incident beam drift can be compensated. The experimental results show that the proposed system has a deviation of 1 μm in the range of 200 mm for distance measurements, and a deviation of 1.3 μm in the range of 2 mm for straightness error measurements.

  3. Dynamic grazing incidence fast atom diffraction during molecular beam epitaxial growth of GaAs

    International Nuclear Information System (INIS)

    Atkinson, P.; Eddrief, M.; Etgens, V. H.; Khemliche, H.; Debiossac, M.; Mulier, M.; Lalmi, B.; Roncin, P.; Momeni, A.

    2014-01-01

    A Grazing Incidence Fast Atom Diffraction (GIFAD) system has been mounted on a commercial molecular beam epitaxy chamber and used to monitor GaAs growth in real-time. In contrast to the conventionally used Reflection High Energy Electron Diffraction, all the GIFAD diffraction orders oscillate in phase, with the change in intensity related to diffuse scattering at step edges. We show that the scattered intensity integrated over the Laue circle is a robust method to monitor the periodic change in surface roughness during layer-by-layer growth, with oscillation phase and amplitude independent of incidence angle and crystal orientation. When there is a change in surface reconstruction at the start of growth, GIFAD intensity oscillations show that there is a corresponding delay in the onset of layer-by-layer growth. In addition, changes in the relative intensity of different diffraction orders have been observed during growth showing that GIFAD has the potential to provide insight into the preferential adatom attachment sites on the surface reconstruction during growth.

  4. Malfunctions of Implantable Cardiac Devices in Patients Receiving Proton Beam Therapy: Incidence and Predictors

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Daniel R., E-mail: dgomez@mdanderson.org [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Poenisch, Falk [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Pinnix, Chelsea C. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Sheu, Tommy [Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Chang, Joe Y. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Memon, Nada [Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Mohan, Radhe [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Rozner, Marc A. [Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Dougherty, Anne H. [Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2013-11-01

    Purpose: Photon therapy has been reported to induce resets of implanted cardiac devices, but the clinical sequelae of treating patients with such devices with proton beam therapy (PBT) are not well known. We reviewed the incidence of device malfunctions among patients undergoing PBT. Methods and Materials: From March 2009 through July 2012, 42 patients with implanted cardiac implantable electronic devices (CIED; 28 pacemakers and 14 cardioverter-defibrillators) underwent 42 courses of PBT for thoracic (23, 55%), prostate (15, 36%), liver (3, 7%), or base of skull (1, 2%) tumors at a single institution. The median prescribed dose was 74 Gy (relative biological effectiveness; range 46.8-87.5 Gy), and the median distance from the treatment field to the CIED was 10 cm (range 0.8-40 cm). Maximum proton and neutron doses were estimated for each treatment course. All CIEDs were checked before radiation delivery and monitored throughout treatment. Results: Median estimated peak proton and neutron doses to the CIED in all patients were 0.8 Gy (range 0.13-21 Gy) and 346 Sv (range 11-1100 mSv). Six CIED malfunctions occurred in 5 patients (2 pacemakers and 3 defibrillators). Five of these malfunctions were CIED resets, and 1 patient with a defibrillator (in a patient with a liver tumor) had an elective replacement indicator after therapy that was not influenced by radiation. The mean distance from the proton beam to the CIED among devices that reset was 7.0 cm (range 0.9-8 cm), and the mean maximum neutron dose was 655 mSv (range 330-1100 mSv). All resets occurred in patients receiving thoracic PBT and were corrected without clinical incident. The generator for the defibrillator with the elective replacement indicator message was replaced uneventfully after treatment. Conclusions: The incidence of CIED resets was about 20% among patients receiving PBT to the thorax. We recommend that PBT be avoided in pacing-dependent patients and that patients with any type of CIED receiving

  5. Malfunctions of Implantable Cardiac Devices in Patients Receiving Proton Beam Therapy: Incidence and Predictors

    International Nuclear Information System (INIS)

    Gomez, Daniel R.; Poenisch, Falk; Pinnix, Chelsea C.; Sheu, Tommy; Chang, Joe Y.; Memon, Nada; Mohan, Radhe; Rozner, Marc A.; Dougherty, Anne H.

    2013-01-01

    Purpose: Photon therapy has been reported to induce resets of implanted cardiac devices, but the clinical sequelae of treating patients with such devices with proton beam therapy (PBT) are not well known. We reviewed the incidence of device malfunctions among patients undergoing PBT. Methods and Materials: From March 2009 through July 2012, 42 patients with implanted cardiac implantable electronic devices (CIED; 28 pacemakers and 14 cardioverter-defibrillators) underwent 42 courses of PBT for thoracic (23, 55%), prostate (15, 36%), liver (3, 7%), or base of skull (1, 2%) tumors at a single institution. The median prescribed dose was 74 Gy (relative biological effectiveness; range 46.8-87.5 Gy), and the median distance from the treatment field to the CIED was 10 cm (range 0.8-40 cm). Maximum proton and neutron doses were estimated for each treatment course. All CIEDs were checked before radiation delivery and monitored throughout treatment. Results: Median estimated peak proton and neutron doses to the CIED in all patients were 0.8 Gy (range 0.13-21 Gy) and 346 Sv (range 11-1100 mSv). Six CIED malfunctions occurred in 5 patients (2 pacemakers and 3 defibrillators). Five of these malfunctions were CIED resets, and 1 patient with a defibrillator (in a patient with a liver tumor) had an elective replacement indicator after therapy that was not influenced by radiation. The mean distance from the proton beam to the CIED among devices that reset was 7.0 cm (range 0.9-8 cm), and the mean maximum neutron dose was 655 mSv (range 330-1100 mSv). All resets occurred in patients receiving thoracic PBT and were corrected without clinical incident. The generator for the defibrillator with the elective replacement indicator message was replaced uneventfully after treatment. Conclusions: The incidence of CIED resets was about 20% among patients receiving PBT to the thorax. We recommend that PBT be avoided in pacing-dependent patients and that patients with any type of CIED receiving

  6. Wideband converter of a charge of particle beam incident on a Faraday cylinder into a number of pulses

    International Nuclear Information System (INIS)

    Shchagin, A.V.; Lysenko, V.F.

    1985-01-01

    An electric circuit of a beam positive charge-pulse converter during beam incidence on a Faraday cylinder (conversion of Faraday cylinder current into F frequency, where F=10 10 J, where J - is the Faraday cylinder current) is described. Conversion ratio is 10 10 pulses/KP (10 10 Hz/A). Input current change limits are 10 -10 -10 -4 A. Conversion error is |ΔF| -3 F +0.1 Hz). ''Dead'' time is absent. Input resistance of the converter is close to zero

  7. A code to determine the energy distribution, the incident energy and the flux of a beam of light ions into a stack of foils

    International Nuclear Information System (INIS)

    Sonzogni, A.A.; Romo, A.S.M.A.; Frosch, W.R.; Nassiff, S.J.

    1992-01-01

    The stacked-foil technique is one of the most used methods to obtain excitation functions of nuclear reactions using light ions as projectiles. The purpose of this program is the calculation of the energy of the beam in the stack, as well as to obtain the incident energy and the flux of the beam by using monitor excitation functions. (orig.)

  8. Expanded level of sympathetic chain removal does not increase the incidence or severity of compensatory hyperhidrosis after endoscopic thoracic sympathectomy.

    Science.gov (United States)

    Gunn, Tyler M; Davis, Diane M; Speicher, James E; Rossi, Nicholas P; Parekh, Kalpaj R; Lynch, William R; Iannettoni, Mark D

    2014-12-01

    Compensatory hyperhidrosis is a common devastating adverse effect after endoscopic thoracic sympathectomy for patients undergoing surgical treatment of primary hyperhidrosis. We sought to determine whether a correlation existed in our patient population between the level and extent of sympathetic chain resection and the subsequent development of compensatory hyperhidrosis. All patients undergoing endoscopic thoracic sympathectomy in the T2-T3, T2-T4, T2-T5, or T2-T6 levels for palmar or axillary hyperhidrosis at the University of Iowa Hospital and Clinics (n = 97) from January 2004 to January 2013 were retrospectively reviewed. Differences in the preoperative patient characteristics were not statistically significant among the patients receiving T2-T3, T2-T4, T2-T5, or T2-T6 level resections. Of the 97 included patients, 28 (29%) experienced transient compensatory hyperhidrosis and 4 (4%) complained of severe compensatory hyperhidrosis and required additional treatment. No operative mortalities occurred, and the morbidity was similar among the groups. Most patients had successful outcomes after undergoing extensive resection without changes in the incidence of compensatory hyperhidrosis. Therefore, we recommend performing complete and adequate resection for relief of symptoms in patients with primary hyperhidrosis. Copyright © 2014 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

  9. Expanded Level of Sympathetic Chain Removal Does Not Increase Incidence or Severity of Compensatory Hyperhidrosis Following Endoscopic Thoracic Sympathectomy

    Science.gov (United States)

    Gunn, Tyler M.; Davis, Diane M.; Speicher, James E.; Rossi, Nicholas P.; Parekh, Kalpaj R.; Lynch, William R.; Iannettoni, Mark D.

    2015-01-01

    Objective Compensatory hyperhidrosis is a common devastating adverse effect following endoscopic thoracic sympathectomy for patients undergoing surgical treatment of primary hyperhidrosis. We sought to determine if there was a correlation in our patient population between the level and extent of sympathetic chain resection and the subsequent development of compensatory hyperhidrosis. Methods All patients undergoing endoscopic thoracic sympathectomy in the T2-3, T2-4, T2-5, or T2-6 levels for palmar or axillary hyperhidrosis at the University of Iowa Hospital and Clinics (n=97) between January 2004 and January 2013 were retrospectively reviewed. Results Differences in preoperative patient characteristics were not statistically significant between patients receiving either T2-3, T2-4, T2-5, or T2-6 level resections. Of the ninety-seven patients included in this study, twenty-eight patients (29%) experienced transient compensatory hyperhidrosis and four patients (4%) complained of severe compensatory hyperhidrosis and required further treatment. There were no operative mortalities and morbidity was similar amongst the groups. Conclusions Most patients had successful outcomes after undergoing extensive resection without change in incidence of compensatory hyperhidrosis. Therefore, we recommend performing a complete and adequate resection for relief of symptoms in patients with primary hyperhidrosis. PMID:25131173

  10. Maximum dose angle for oblique incidence on primary beam protective barriers in the design of medical radiation therapy facilities

    International Nuclear Information System (INIS)

    Fondevila, Damian; Arbiser, Silvio; Sansogne, Rosana; Brunetto, Monica; Dosoretz, Bernardo

    2008-01-01

    Primary barrier determinations for the shielding of medical radiation therapy facilities are generally made assuming normal beam incidence on the barrier, since this is geometrically the most unfavorable condition for that shielding barrier whenever the occupation line is allowed to run along the barrier. However, when the occupation line (for example, the wall of an adjacent building) runs perpendicular to the barrier (especially roof barrier), then two opposing factors come in to play: increasing obliquity angle with respect to the barrier increases the attenuation, while the distance to the calculation point decreases, hence, increasing the dose. As a result, there exists an angle (α max ) for which the equivalent dose results in a maximum, constituting the most unfavorable geometric condition for that shielding barrier. Based on the usual NCRP Report No. 151 model, this article presents a simple formula for obtaining α max , which is a function of the thickness of the barrier (t E ) and the equilibrium tenth-value layer (TVL e ) of the shielding material for the nominal energy of the beam. It can be seen that α max increases for increasing TVL e (hence, beam energy) and decreases for increasing t E , with a range of variation that goes from 13 to 40 deg for concrete barriers thicknesses in the range of 50-300 cm and most commercially available teletherapy machines. This parameter has not been calculated in the existing literature for radiotherapy facilities design and has practical applications, as in calculating the required unoccupied roof shielding for the protection of a nearby building located in the plane of the primary beam rotation

  11. Peculiarities of the Self-Action of Inclined Wave Beams Incident on a Discrete System of Optical Fibers

    Science.gov (United States)

    Litvak, A. G.; Mironov, V. A.; Skobelev, S. A.; Smirnov, L. A.

    2018-01-01

    Based on a discrete nonlinear Schrödinger equation (DNSE), we studied analytically and numerically the peculiarities of the self-action of one-dimensional quasi-optic wave beams injected into a spatially inhomogeneous medium consisting of a set of equidistant mutually coupled optical fibers. A variational approach allowing the prediction of the global evolution of localized fields with the initially plane phase front was developed. The self-consistent equations are obtained for the main parameters of such beams (the position of the center of mass, the effective width, and linear and quadratic phase-front corrections) in the aberrationless approximation. The case of radiation incident on a periodic system of nonlinear optical fibers at an angle to the axis oriented along them is analyzed in detail. It is shown that for the radiation power exceeding a critical value, the self-focusing of the wave field is observed, which is accompanied by the shift of the intensity maximum followed by the concentration of the main part of radiation only in one of the structural elements of the array under study. In this case, the beams propagate along paths considerably different from linear and the direction of their propagation changes compared to the initial direction. Asymptotic expressions are found that allow us to estimate the self-focusing length and to determine quite accurately the final position of a point with the maximum field amplitude after radiation trapping a channel. The results of the qualitative study of the possible self-channeling regimes for wave beams in a system of weakly coupled optical fibers in the aberrationless approximation are compared with the results of direct numerical simulations within the DNSE framework.

  12. SU-E-T-115: Dose Perturbation Study of Self-Expandable Metal and Polyester Esophageal Stents in Proton Therapy Beams

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S; Li, Z [University of Florida Proton Therapy Institute, Jacksonville, FL (United States); Jalaj, S; McGaw, C; B K, John; J S, Scolapio; J C, Munoz [Division of Gastoenterology, Department of Medicine, University of Florida, Jacksonville, FL (United States)

    2014-06-01

    Purpose: This work investigates dose perturbations due to Self-expandable metal and polyester esophageal stents undergoing proton radiotherapy for esophageal cancer. Methods: Five commercially available esophageal stents made of nitinol (Evolution, Wallflex and Ultraflex), stainless steel (Z-Stent) and polyester (Polyflex) were tested. Radiochromic film (GafChromic EBT3 film, Ashland, Covington, KY) wrapped around a stent and a 12cc syringe was irradiated with 2CGE (Cobalt Gray Equivalent) of proton beam in a custom fabricated acrylic phantom. An air-hollow syringe simulates the esophagus. Results: The Z-stent created the largest dose perturbations ranges from -14.5% to 6.1% due to the steel composition. The WallFlex, Evolution and Ultraflex stents produced the dose perturbation ranges of (−9.2%∼8.6%), (−6.8%∼5.7%) and (−6.2%∼6.2%), respectively. The PolyFlex stent contains the radiopaque tungsten markers located top, middle and bottom portions. When the focal cold spots induced by the markers were excluded in the analysis, the dose perturbation range was changed from (−11.6%∼6.4%) to (−0.6%∼5.0%). Conclusion: The magnitude of dose perturbation is related to material of a metallic stent. The non-metallic stent such as PolyFlex shows relatively lower dose perturbation than metallic stents except a radiopaque marker region. Overall Evolution and Ultraflex stent appear to be less dose perturbations. The largest dose perturbations (cold spots) were located at both edges of stents in distal area for the single proton beam irradiation study. The analysis of more than two proton beam which is more typical clinical beam arrangement would be necessary to minimize the doe perturbation effect in proton ratiotherapy.

  13. X-ray study of a test quadrant of the SODART telescopes using the expanded beam x-ray optics facility at the Daresbury synchrotron

    DEFF Research Database (Denmark)

    Christensen, Finn Erland; Hornstrup, Allan; Frederiksen, P.

    1994-01-01

    The imaging properties of a test model of the SODART telescopes have been studied using an expanded beam X-ray facility at the Daresbury synchrotron. The encircled power and the point spread function at three energies 6.627 keV, 8.837 keV and 11.046 keV have been measured using 1D and 2D position......V the HPD is 2.5 - 3.0 arcmin for all detectors whereas it is somewhat larger at 11.046 keV for HEPC and LEPC but essentially unchanged for SIXA. Finally, the data are used to point to improvements that can be introduced during the manufacture of the flight telescopes....

  14. X-ray study of a SODART flight telescope using the expanded beam x-ray optics beamline at the Daresbury synchrotron

    DEFF Research Database (Denmark)

    Christensen, Finn Erland; Hornstrup, Allan; Frederiksen, P. K.

    1995-01-01

    The on- and off-axis imaging properties of the first of two SODART flight telescopes have been studied using the expanded beam x-ray facility at the Daresbury synchrotron. From on- axis measurements the encircled power distribution and the point spread function at three energies 6.627 keV, 8.837 ke...... element solid state array detector (SIXA). We found that the HPD decreases with increasing energy due to poorer figure error of the outermost mirrors. The HPD falls in the range from 2.3 to 3 arcmin for all detectors. Residual misalignment of the individual quadrants of the telescope was found...... to contribute to the HPD by approximately 10%. If 33% of the geometric telescope area near the edges of the quadrants are covered a reduction of 10% of the HPD can be obtained. On- and off-axis images generated from the one dimensional intensity distribution are presented. Finally the data have been used...

  15. Bigelow Expandable Activity Module Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Bigelow Expandable Activity Module (BEAM) project is a NASA-industry partnership with Bigelow Aerospace (BA) that has developing the first human-rated expandable...

  16. Diagnosis of secondary caries in esthetic restorations: influence of the incidence vertical angle of the X-ray beam.

    Science.gov (United States)

    Moreira, Patrícia Lima; Messora, Michel Reis; Pereira, Stela Márcia; Almeida, Solange Maria de; Cruz, Adriana Dibo da

    2011-01-01

    The aim of this study was to evaluate the accuracy on the diagnosis of secondary caries-like lesions simulated on esthetic restorations of different materials, changing the incidence vertical angle (IVA) of the x-ray beam. Twenty human teeth received MOD inlay preparations. In the experimental group (n=10), a round cavity was made in the floor of the proximal box to simulate the caries-like lesion. All teeth were restored with 3 composite resins (Charisma, Filtek-Z250 and TPH-Spectrum) at 3 moments. Two radiographic images were acquired with 0º and 10º IVA. Ten observers evaluated the images using a 5-point confidence scale. Intra- and interobserver reliability was analyzed with the Interclass Correlation Coefficient and the diagnostic accuracy was evaluated using the area under the ROC curve (A(z)), Friedman test and Wilcoxon test (α=0.05). Higher accuracy values were obtained with 10º IVA (A(z)=0.66, Filtek-Z250>A(z)=0.56, TPH-Spectrum) compared to 0º (A(z)=0.55, Charisma>A(z)=0.37, TPH-Spectrum), though without statistically significant difference (p>0.05). The detection of secondary caries-like lesions simulated on esthetic restorations of different materials suffered no negative influence by changing the IVA of the x-ray beam.

  17. Optimal design and fabrication method for antireflection coatings for P-polarized 193 nm laser beam at large angles of incidence (68°-74°).

    Science.gov (United States)

    Jin, Jingcheng; Jin, Chunshui; Li, Chun; Deng, Wenyuan; Chang, Yanhe

    2013-09-01

    Most of the optical axes in modern systems are bent for optomechanical considerations. Antireflection (AR) coatings for polarized light at oblique incidence are widely used in optical surfaces like prisms or multiform lenses to suppress undesirable reflections. The optimal design and fabrication method for AR coatings with large-angle range (68°-74°) for a P-polarized 193 nm laser beam is discussed in detail. Experimental results showed that after coating, the reflection loss of a P-polarized laser beam at large angles of incidence on the optical surfaces is reduced dramatically, which could greatly improve the output efficiency of the optical components in the deep ultraviolet vacuum range.

  18. Second cancer incidence risk estimates using BEIR VII models for standard and complex external beam radiotherapy for early breast cancer

    International Nuclear Information System (INIS)

    Donovan, E. M.; James, H.; Bonora, M.; Yarnold, J. R.; Evans, P. M.

    2012-01-01

    Purpose: To compare organ specific cancer incidence risks for standard and complex external beam radiotherapy (including cone beam CT verification) following breast conservation surgery for early breast cancer.Method: Doses from breast radiotherapy and kilovoltage cone beam CT (CBCT) exposures were obtained from thermoluminescent dosimeter measurements in an anthropomorphic phantom in which the positions of radiosensitive organs were delineated. Five treatment deliveries were investigated: (i) conventional tangential field whole breast radiotherapy (WBRT), (ii) noncoplanar conformal delivery applicable to accelerated partial beast irradiation (APBI), (iii) two-volume simultaneous integrated boost (SIB) treatment, (iv) forward planned three-volume SIB, and (v) inverse-planned three volume SIB. Conformal and intensity modulated radiotherapy methods were used to plan the complex treatments. Techniques spanned the range from simple methods appropriate for patient cohorts with a low cancer recurrence risk to complex plans relevant to cohorts with high recurrence risk. Delineated organs at risk included brain, salivary glands, thyroid, contralateral breast, left and right lung, esophagus, stomach, liver, colon, and bladder. Biological Effects of Ionizing Radiation (BEIR) VII cancer incidence models were applied to the measured mean organ doses to determine lifetime attributable risk (LAR) for ages at exposure from 35 to 80 yr according to radiotherapy techniques, and included dose from the CBCT imaging. Results: All LAR decreased with age at exposure and were lowest for brain, thyroid, liver, and bladder (<0.1%). There was little dependence of LAR on radiotherapy technique for these organs and for colon and stomach. LAR values for the lungs for the three SIB techniques were two to three times those from WBRT and APBI. Uncertainties in the LAR models outweigh any differences in lung LAR between the SIB methods. Constraints in the planning of the SIB methods ensured that

  19. Second cancer incidence risk estimates using BEIR VII models for standard and complex external beam radiotherapy for early breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Donovan, E. M.; James, H.; Bonora, M.; Yarnold, J. R.; Evans, P. M. [Joint Department of Physics, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Sutton SM2 5PT (United Kingdom); Physics Department, Ipswich Hospital NHS Foundation Trust, Ipswich IP4 5PD (United Kingdom); Department of Academic Radiotherapy, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Sutton SM2 5PT, United Kingdom and School of Radiotherapy, University of Milan, Milan 20122 (Italy); Department of Academic Radiotherapy, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Sutton SM2 5PT (United Kingdom); Centre for Vision Speech and Signal Processing, University of Surrey, Guildford GU2 7XH (United Kingdom)

    2012-10-15

    Purpose: To compare organ specific cancer incidence risks for standard and complex external beam radiotherapy (including cone beam CT verification) following breast conservation surgery for early breast cancer.Method: Doses from breast radiotherapy and kilovoltage cone beam CT (CBCT) exposures were obtained from thermoluminescent dosimeter measurements in an anthropomorphic phantom in which the positions of radiosensitive organs were delineated. Five treatment deliveries were investigated: (i) conventional tangential field whole breast radiotherapy (WBRT), (ii) noncoplanar conformal delivery applicable to accelerated partial beast irradiation (APBI), (iii) two-volume simultaneous integrated boost (SIB) treatment, (iv) forward planned three-volume SIB, and (v) inverse-planned three volume SIB. Conformal and intensity modulated radiotherapy methods were used to plan the complex treatments. Techniques spanned the range from simple methods appropriate for patient cohorts with a low cancer recurrence risk to complex plans relevant to cohorts with high recurrence risk. Delineated organs at risk included brain, salivary glands, thyroid, contralateral breast, left and right lung, esophagus, stomach, liver, colon, and bladder. Biological Effects of Ionizing Radiation (BEIR) VII cancer incidence models were applied to the measured mean organ doses to determine lifetime attributable risk (LAR) for ages at exposure from 35 to 80 yr according to radiotherapy techniques, and included dose from the CBCT imaging. Results: All LAR decreased with age at exposure and were lowest for brain, thyroid, liver, and bladder (<0.1%). There was little dependence of LAR on radiotherapy technique for these organs and for colon and stomach. LAR values for the lungs for the three SIB techniques were two to three times those from WBRT and APBI. Uncertainties in the LAR models outweigh any differences in lung LAR between the SIB methods. Constraints in the planning of the SIB methods ensured that

  20. Incidence, feasibility and outcome of percutaneous coronary intervention after transcatheter aortic valve implantation with a self-expanding prosthesis. Results from a single center experience.

    Science.gov (United States)

    Allali, Abdelhakim; El-Mawardy, Mohamed; Schwarz, Bettina; Sato, Takao; Geist, Volker; Toelg, Ralph; Richardt, Gert; Abdel-Wahab, Mohamed

    2016-09-01

    Percutaneous coronary intervention (PCI) after transcatheter aortic valve implantation (TAVI) can become technically challenging after implantation of the self-expanding Medtronic CoreValve (MCV) device, which completely covers the aortic root. The aim of this study was to report on the incidence, feasibility and outcome of PCI after TAVI with the MCV device. Between 2007 and 2014, all patients subjected to PCI after MCV implantation in a single-center institutional TAVI database were retrospectively identified. Clinical, angiographic and procedural characteristics were reviewed and analyzed. We identified a total of 17 patients (5.7%) treated with 24 PCI procedures for 29 lesions at a median of 17.7months (range 1-72) after MCV implantation. The mean age was 79.7±6.8years and the mean logistic EuroSCORE was 30.3%±18.9%. Nine procedures were performed for patients with acute coronary syndrome. 89.6% of the treated lesions were of type B2/C and 79.3% were de novo ones. A median of one guiding catheter was necessary to intubate the target coronary ostium (range 1-10) and 95% of the lesions on the left coronary artery were treated through a Judkins catheter. In one primary PCI for STEMI the intubation of the right coronary ostium was not successful. Final procedural success was obtained in 95.8%, and peri-procedural death occurred in one patient. The need for PCI after MCV is not uncommon and is mostly related to coronary artery disease progression. PCI after MCV is usually feasible and safe, but coronary intubation in an emergency setting can be challenging. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Molecular-beam epitaxy growth and structural characterization of semiconductor-ferromagnet heterostructures by grazing incidence X-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Satapathy, D.K.

    2005-12-19

    The present work is devoted to the growth of the ferromagnetic metal MnAs on the semiconductor GaAs by molecular-beam epitaxy (MBE). The MnAs thin films are deposited on GaAs by molecular-beam epitaxy (MBE). Grazing incidence diffraction (GID) and reflection high-energy electron diffraction (RHEED) are used in situ to investigate the nucleation, evolution of strain, morphology and interfacial structure during the MBE growth. Four stages of the nucleation process during growth of MnAs on GaAs(001) are revealed by RHEED azimuthal scans. GID shows that further growth of MnAs films proceed via the formation of relaxed islands at a nominal thickness of 2.5 ML which increase in size and finally coalesce to form a continuous film. Early on, an ordered array of misfit dislocations forms at the interface releasing the misfit strain even before complete coalescence occurs. The fascinating complex nucleation process of MnAs on GaAs(0 0 1) contains elements of both Volmer-Weber and Stranski-Krastanov growth. A nonuniform strain amounting to 0.66%, along the [1 -1 0] direction and 0.54%, along the [1 1 0] direction is demonstrated from x-ray line profile analysis. A high correlation between the defects is found along the GaAs[1 1 0] direction. An extremely periodic array of misfit dislocations with a period of 4.95{+-}0.05 nm is formed at the interface along the [1 1 0] direction which releases the 7.5% of misfit. The inhomogeneous strain due to the periodic dislocations is confined at the interface within a layer of 1.6 nm thickness. The misfit along the [1 -1 0] direction is released by the formation of a coincidence site lattice. (orig.)

  2. Fragmentation and direct transfer reactions for 40Ar incident beam on 27Al target at 1760 MeV

    International Nuclear Information System (INIS)

    Cisse, Ousmane

    1985-01-01

    Peripheral collision studies performed with 40 Ar projectiles at 44 MeV/A and 27 Al target show that both fragmentation and transfer reactions can be discerned in this type of interaction. The experimental observation of fragments with masses charges and velocities close to those of the incident beam are the signature of transfer reactions and a detailed analysis of the energy spectra of such fragments has been carried out and interpreted in terms of a direct diffraction transfer model. On the other hand, for large mass transfer reactions, abrasion is the suitable mechanism. Inclusive fragment measurement together with the appropriate residual nuclei-fragment coincidence results then provides experimental data in good agreement with the theoretical predictions obtained from a participant spectator model. These investigations also indicate that the separation energies of the participant from the spectator nucleus, at least within the framework of the above model, can be interpreted in terms of a friction force which becomes more efficient as the projectile energy decreases. (author) [fr

  3. Long range heliostat target using array of normal incidence pyranometers to evaluate a beam of solar radiation

    Science.gov (United States)

    Ghanbari, Cheryl M; Ho, Clifford K; Kolb, Gregory J

    2014-03-04

    Various technologies described herein pertain to evaluating a beam reflected by a heliostat. A portable target that has an array of sensors mounted thereupon is configured to capture the beam reflected by the heliostat. The sensors in the array output measured values indicative of a characteristic of the beam reflected by the heliostat. Moreover, a computing device can generate and output data corresponding to the beam reflected by the heliostat based on the measured values indicative of the characteristic of the beam received from the sensors in the array.

  4. Influence of Polarization of the Incident Beam on Integrated Intensities in X-Ray Energy-Dispersive Diffractometry

    DEFF Research Database (Denmark)

    Olsen, J. Staun; Buras, B.; Jensen, T.

    1978-01-01

    Polarization measurements of the primary X-ray beam produced by thick copper and tungsten anodes are reported and formulas derived for integrated intensities of Bragg reflections in energy-dispersive diffractometry with the polarization of the primary beam taken into account. It was found...

  5. Evaluation by dental cone-beam computed tomography of the incidence and sites of branches of the inferior dental canal that supply mandibular third molars.

    Science.gov (United States)

    Ogawa, A; Fukuta, Y; Nakasato, H; Nakasato, S

    2016-12-01

    Our aim was to assess the incidence and anatomical site of branches of the inferior dental canal that supply mandibular third molars using dental cone-beam computed tomography (CT). We evaluated the incidence and diameter of branches of the inferior dental canal using 272 cone-beam CT mandibular scans from 172 patients referred for imaging before the extraction of impacted mandibular third molars. We found three typical branching patterns from the inferior dental canal in the third molar region: the retromolar canal (in the retromolar triangle), the dental canal (that courses directly beneath the socket of the third molar), and the accessory canal (that courses through the socket and leads from the inferior dental canal to a bony ridge). The incidences of retromolar, dental, and accessory canals were 75 (28%), 223 (82%), and 21 (8%), respectively, with mean diameters of 0.9 (0.4), 0.7 (0.5), and 1.1 (0.4) mm, respectively. Operative injury to the neurovascular contents within the branches of the inferior dental canal can lead to excessive bleeding and postoperative paraesthesia, so identification of its branches on preoperative cone-beam CT images may prove useful during extraction of impacted mandibular third molars or when harvesting bone blocks from the region of mandibular third molars. We also describe two cases of branches detected on panoramic and cone-beam CT images that prompted this research. Copyright © 2016 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  6. Incident neutron spectra on the first wall and their application to energetic ion diagnostics in beam-injected deuterium-tritium tokamak plasmas

    Science.gov (United States)

    Sugiyama, S.; Matsuura, H.; Uchiyama, D.

    2017-09-01

    A diagnostic method for small non-Maxwellian tails in fuel-ion velocity distribution functions is proposed; this method uses the anisotropy of neutron emissions, and it is based on the numerical analysis of the incident fast neutron spectrum on the first wall of a fusion device. Neutron energy spectra are investigated for each incident position along the first wall and each angle of incidence assuming an ITER-like deuterium-tritium plasma; it is heated by tangential-neutral-beam injection. Evaluating the incident neutron spectra at all wall positions and angles of incidence enables the selective measurement of non-Gaussian components in the neutron emission spectrum for energetic ion diagnostics; in addition, the optimal detector position and orientation can be determined. At the optimal detector position and orientation, the ratio of non-Gaussian components to the Gaussian peak can be two orders of magnitude greater than the ratio in the neutron emission spectrum. This result can improve the accuracy of energetic ion diagnostics in plasmas when small, anisotropic non-Maxwellian tails are formed in fuel ion velocity distribution functions. We focus on the non-Gaussian components greater than 14 MeV, where the effect of the background noise (i.e., slowing-down neutrons by scattering throughout the machine structure) can be ignored.

  7. Single-beam integrating sphere spectrophotometer for reflectance and transmittance measurements versus angle of incidence in the solar wavelength range on diffuse and specular samples

    Science.gov (United States)

    Nostell, Per; Roos, Arne; Rönnow, Daniel

    1999-05-01

    A multipurpose instrument for the measurement of reflectance and transmittance versus angle of incidence for both specular and diffuse samples in the solar wavelength range has been constructed and evaluated. The instrument operates in the single-beam mode and uses a common light source for three experimental setups. Two integrating spheres, 20 cm in diameter, are used for diffuse transmittance and reflectance measurements. The transmittance sphere can be turned around an axis through the sample to vary the angle of incidence. The reflectance sphere uses a center mounted sample and a special feature is the position of the detector, which is mounted on the sample holder at the center of the sphere. This way the detector always sees the same part of the sphere wall and no light can reach the detector directly from the sample. The third setup is an absolute instrument for specular samples. It uses a small averaging sphere as a detector. The detector is mounted on an arm which rotates around the center of the sample, and it can thus pick up both the reflected and transmitted beams including all multiply reflected components. The averaging sphere detector is insensitive to small side shifts of the detected beams and no multiple reflections between detector and optical system occur. In this report a number of calibration procedures are presented for the three experimental setups and models for the calculation of correct transmittance and reflectance values from measured data are presented. It is shown that for integrating sphere measurements, the geometry of the sphere and the diffusivity of the sample as well as the sphere wall reflectance and port losses are important factors that influence the result. For the center mounted configuration these factors are particularly important and special emphasis is given to the evaluation of the reflectance sphere model. All three instrument setups are calibrated using certified reference materials and nonscattering mirrors and

  8. Incidence of primary hypothyroidism in patients exposed to therapeutic external beam radiation, where radiation portals include a part or whole of the thyroid gland

    Directory of Open Access Journals (Sweden)

    B A Laway

    2012-01-01

    Full Text Available Introduction: Hypothyroidism is a known consequence of external-beam radiotherapy to the neck encompassing a part or whole of the thyroid gland. In this non-randomized prospective study, we have tried to evaluate the response of the thyroid gland to radiation by assessing thyroid function before irradiation and at regular intervals after irradiation. Aims and Objectives: The aim of this study were to assess in the cancer patients, who were exposed to the therapeutic external beam radiation, where radiation portals include a part or whole of the thyroid gland: the incidence of primary hypothyroidism, the time required to become hypothyroid, any relation between the total dose for the development of hypothyroidism, and whether there are any patient or treatment-related factors that are predictive for the development of hypothyroidism, including the use of concurrent chemotherapy. Materials and Methods: This non-randomized, prospective study was conducted for a period of 2 years in which thyroid function was assessed in 59 patients (cases of head and neck cancer, breast cancer, lymphoma patients and other malignancies, who had received radiotherapy to the neck region. 59 euthyroid healthy patients (controls were also taken, who had not received the neck irradiation. These patients/controls were assessed periodically for 2 years. Results: The incidence of hypothyroidism after external beam radiation therapy (EBRT to neck where radiation portals include part or whole of the thyroid gland was 16.94%, seven cases had subclinical hypothyroidism (11.86% and three cases had clinical hypothyroidism (5.08%. Mean time for development of hypothyroidism was 4.5 months. There was no effect of age, gender, primary tumor site, radiation dose and chemotherapy, whether neoadjuvant or concurrent with the development of hypothyroidism. Conclusion: In summary, we found that thyroid dysfunction is a prevalent, yet easily treatable source of morbidity in patients

  9. Use of External Beam Radiotherapy Is Associated With Reduced Incidence of Second Primary Head and Neck Cancer: A SEER Database Analysis

    International Nuclear Information System (INIS)

    Rusthoven, Kyle; Chen Changhu; Raben, David; Kavanagh, Brian

    2008-01-01

    Purpose: Patients with head and neck cancer have a significant risk of developing a second primary cancer of the head and neck. We hypothesized that treatment with external beam radiotherapy (RT) might reduce this risk, because RT can eradicate occult foci of second head and neck cancer (HNCA). Methods and Materials: The data of patients with Surveillance, Epidemiology, and End Results Historic Stage A localized squamous cell carcinoma of the oral cavity, larynx, and pharynx were queried using the Surveillance, Epidemiology, and End Results database. For patients treated with or without RT, the incidence of second HNCA was determined and compared using the log-rank method. Cox proportional hazards analysis was performed for each site, evaluating the influence of covariates on the risk of second HNCA. Results: Between 1973 and 1997, 27,985 patients were entered with localized HNCA. Of these patients, 44% had received RT and 56% had not. The 15-year incidence of second HNCA was 7.7% with RT vs. 10.5% without RT (hazard ratio 0.71, p <0.0001). The effect of RT was more profound in patients diagnosed between 1988 and 1997 (hazard ratio 0.53, p <0.0001) and those with pharynx primaries (hazard ratio 0.47, p <0.0001). On multivariate analysis, RT was associated with a reduced risk of second HNCA for pharynx (p <0.0001) and larynx (p = 0.04) tumors. For oral cavity primaries, RT was associated with an increased risk of second HNCA in patients treated before 1988 (p <0.001), but had no influence on patients treated between 1988 and 1997 (p = 0.91). Conclusion: For localized HNCA, RT is associated with a reduced incidence of second HNCA. These observations are consistent with the eradication of microscopic foci of second HNCA with external beam RT

  10. Expanding subjectivities

    DEFF Research Database (Denmark)

    Lundgaard Andersen, Linda; Soldz, Stephen

    2012-01-01

    A major theme in recent psychoanalytic thinking concerns the use of therapist subjectivity, especially “countertransference,” in understanding patients. This thinking converges with and expands developments in qualitative research regarding the use of researcher subjectivity as a tool...... to understanding, especially but not exclusively in observational and interview-based studies. Psychodynamic or psychoanalytic approaches to research add an emphasis on unconscious motivational processes in both researchers and research participants that impact research experience and data. Building upon Anglo......-Saxon and continental traditions, this special issue provides examples of the use of researcher subjectivity, informed by psychoanalytic thinking, in expanding research understanding....

  11. Characterization of ion beam sputtered deposited W/Si multilayers by grazing incidence x-ray diffraction and x-ray reflectivity technique

    Science.gov (United States)

    Dhawan, Rajnish; Rai, Sanjay

    2016-05-01

    W/Si multilayers four samples have been deposited on silicon substrate using ion beam sputtering system. Thickness of tungsten (W) varies from around 10 Å to 40 Å while the silicon (Si) thickness remains constant at around 30 Å in multilayers [W-Si]x4. The samples have been characterized by grazing incidence X-ray diffraction (GIXRD) and X-ray reflectivity technique (XRR). GIXRD study shows the crystalline behaviour of W/Si multilayer by varying W thickness and it is found that above 20 Å the W film transform from amorphous to crystalline phase and X-ray reflectivity data shows that the roughnesses of W increases on increasing the W thicknesses in W/Si multilayers.

  12. Effective energies and exposure determinations of two different energy X-ray beams incident on a personnel monitor

    International Nuclear Information System (INIS)

    Okuno, E.; Cruz, M.T. da

    1984-01-01

    The effective energy of one X or gamma ray beam can be determined by means of two thermoluminescent (TL) dosemeters mounted between suitable filters. However, it has been observed that personnel monitors exposed to two different energy ionizing radiations provide different effective energies depeding on the type of TL phosphor used. This fact could be a powerful tool for identifying exposures to radiation with quite different effective energies which are very common in practice. Two types of TL dosemeters were used : pellets of cold pressed natural fluoride and NaCl developed in our own laboratory, and LiF, TLD-100 from Harshaw Chemical Co.. Experimental results obtained with these combined dosemeters after irradiation with different sets of exposures and energy values of ionizing radiations are also presented. (Author) [pt

  13. Study of Hadronic Jets Produced by Charged Pion and Proton Beams Incident on Hydrogen and Aluminum Targets

    Energy Technology Data Exchange (ETDEWEB)

    Yung, Kar Woo [California Inst. of Technology (CalTech), Pasadena, CA (United States)

    1979-09-19

    High transverse momentum ($P_T$) particles are thought to reflect the underlying parton (quark or gluon) mechanisms of hadron interactions. A particularly simple model by Feynman, Field and Fox (or FFF>, involves hard scattering of a pair of partons via gluon exchange (Quantum Chromodynamics or GCD) with subsequent fragmentation or the partons into hadrons. We present results from an experiment (E260 at Fermilab) on the production of Jets (groups of particles) and single charged particles, at both low and high $P_T$, in 200 Gev interactions. The experiment used a calorimeter triggered multiparticle spectrometer. Results are presented on the comparisons of cross sections and associated charged particle distributions for pion and proton beams and aluminium and hydrogen targets.

  14. Expander Codes

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 10; Issue 1. Expander Codes - The Sipser–Spielman Construction. Priti Shankar. General Article Volume 10 ... Author Affiliations. Priti Shankar1. Department of Computer Science and Automation, Indian Institute of Science Bangalore 560 012, India.

  15. Incidência de opacificação de cápsula posterior em pacientes submetidos à facoemulsificação e implante de lentes intra-oculares acrílicas hidrofílicas expansíveis Incidence of posterior capsule opacification in patients submitted to phacoemulsification and expandable acrylic intraocular lens implantation

    Directory of Open Access Journals (Sweden)

    Hilton Arcoverde Gonçalves de Medeiros

    2006-06-01

    Full Text Available OBJETIVO: Avaliar prospectivamente os resultados das lentes intra-oculares de polímeros expansíveis implantadas em pacientes submetidos à facoemulsificação, quanto à incidência de opacificação de cápsula posterior, levando em consideração a biocompatibilidade das lentes expansíveis. MÉTODOS: O grupo de estudo foi composto por 830 pacientes, 1.200 olhos, que foram submetidos a facoemulsificação, utilizando a mesma técnica, variando-se apenas o diâmetro da capsulorrexe, pelo mesmo cirurgião, no período de 1998 a 2002, com implante de lente intra-ocular hidrofílica expansível. O acompanhamento médio foi de 2,4 anos, variando de seis meses a quatro anos. RESULTADOS: O número total de opacificação de cápsula posterior foi de 54 casos. CONCLUSÃO: A incidência de opacificação de cápsula posterior encontrada no grupo foi de 4,6%.PURPOSE: To evaluate prospectively the results of expandable acrylic intraocular lenses in patients submitted to phacoemulsification as regard posterior capsule opacification. METHODS: The study group consisted of 830 patients, 1,200 eyes that underwent phacoemulsification from 1998 to 2002, by the same surgeon, using the same technique but with different diameters of capsulorrhexis, with expandable hydrophilic acrylic intraocular lens implantation. The mean follow-up was 2.4 years, ranging from 6 months to 4 years. RESULTS: The total number of posterior capsule opacification was 54 cases. CONCLUSIONS: The incidence of posterior capsule opacification was 4.6% in these patients.

  16. Partition expanders

    Czech Academy of Sciences Publication Activity Database

    Gavinsky, Dmitry; Pudlák, Pavel

    2017-01-01

    Roč. 60, č. 3 (2017), s. 378-395 ISSN 1432-4350 R&D Projects: GA ČR GBP202/12/G061 Institutional support: RVO:67985840 Keywords : expanders * pseudo randomness * communication complexity Subject RIV: BA - General Mathematics OBOR OECD: Computer sciences, information science, bioinformathics (hardware development to be 2.2, social aspect to be 5.8) Impact factor: 0.645, year: 2016 http://link.springer.com/article/10.1007%2Fs00224-016-9738-5

  17. Partition expanders

    Czech Academy of Sciences Publication Activity Database

    Gavinsky, Dmitry; Pudlák, Pavel

    2017-01-01

    Roč. 60, č. 3 (2017), s. 378-395 ISSN 1432-4350 R&D Projects: GA ČR GBP202/12/G061 Institutional support: RVO:67985840 Keywords : expanders * pseudorandomness * communication complexity Subject RIV: BA - General Mathematics OBOR OECD: Computer sciences, information science, bioinformathics (hardware development to be 2.2, social aspect to be 5.8) Impact factor: 0.645, year: 2016 http://link.springer.com/article/10.1007%2Fs00224-016-9738-5

  18. Incidence of Maxillary Sinus Disease Before Sinus Floor Elevation Surgery as Identified by Cone-Beam Computed Tomography: A Literature Review.

    Science.gov (United States)

    Costa, Fabio; Emanuelli, Enzo; Robiony, Massimo

    2018-04-01

    The purpose of this study is to review the literature to assess the incidence of maxillary sinus disease before sinus floor elevation surgery (SFE) as identified by cone-beam computerized tomography (CBCT). Only studies in which CBCT was performed in patients for dental implant placement in the past 10 years were considered. Eleven studies were identified. A total of 1792 patients were collected. All the studies reviewed reported on thickening of the sinus mucosa as a criterion for sinus disease with different threshold values. All studies reported mucosal thickening (MT) ranging between 25.5% and 93.1%. The mean incidence of MT was 54.99%. Two studies examined the correlation of MT with clinical symptoms. Three studies reported evaluation of the ostiomeatal complex (OMC). There is a high probability of detecting a certain degree of MT in patients referred for SFE. There is no consensus regarding the threshold values beyond which MT is considered pathological. Independently from the threshold values or the type of MT, the studies lack correlation with clinical data regarding patients' sinusitis-related history or symptoms. CBCT with a large field of view to evaluate the OMC is appropriate in patients scheduled for SFE. Future studies should include a systematic correlation with clinical symptoms and the possible presence of OMC obstruction. A clinical assessment that includes nasal endoscopy is indicated when MT and obstruction of the OMC are identified. Surgical correction of OMC obstruction seems to be appropriate to increase the success rate and to avoid possible complication after SFE.

  19. Reduction of the divergence angle of an incident beam to enhance the demagnification factor of a two-stage acceleration lens in a gas ion nanobeam system of several tens of keV

    Science.gov (United States)

    Ishii, Yasuyuki; Kojima, Takuji

    2018-04-01

    The demagnification factor of a two-stage acceleration lens in a gas ion nanobeam system that produces ion beams with energies in the order of 10 keV was enhanced in this study so that a hydrogen ion beam with a diameter of 115 nm could be produced. The reduction of the divergence angle of the incident beam into the two-stage acceleration lens is the effective method for enhancing the demagnification factor. The divergence angle has been gradually reduced by firstly introducing the preacceleration electrodes to control the divergence angle, namely divergence-angle-control electrodes, and secondly replacing an anode with a modified anode that possesses a Pierce electrode, both of which were in an ion source directly connected to the lens. In this study, the divergence angle of less than 3.6 × 10-4 rad that was previously used to produce a 160-nm hydrogen ion beam with the energy of 46 keV by the above procedure was numerically determined using an ion beam extraction simulation code. The determined minimum divergence angle of the incident ion beam was calculated to be 2.0 × 10-4 rad, which was about half of the previously obtained divergence angle; this was used to experimentally form a hydrogen beam with a diameter of 115 ± 10 nm and the energy of 47 keV. The demagnification factor was estimated to be 1,739 using the newly formed hydrogen beam, which was similar to the simulation result.

  20. A comparison of simple and realistic eye models for calculation of fluence to dose conversion coefficients in a broad parallel beam incident of protons

    International Nuclear Information System (INIS)

    Sakhaee, Mahmoud; Vejdani-Noghreiyan, Alireza; Ebrahimi-Khankook, Atiyeh

    2015-01-01

    Radiation induced cataract has been demonstrated among people who are exposed to ionizing radiation. To evaluate the deterministic effects of ionizing radiation on the eye lens, several papers dealing with the eye lens dose have been published. ICRP Publication 103 states that the lens of the eye may be more radiosensitive than previously considered. Detailed investigation of the response of the lens showed that there are strong differences in sensitivity to ionizing radiation exposure with respect to cataract induction among the tissues of the lens of the eye. This motivated several groups to look deeper into issue of the dose to a sensitive cell population within the lens, especially for radiations with low energy penetrability that have steep dose gradients inside the lens. Two sophisticated mathematical models of the eye including the inner structure have been designed for the accurate dose estimation in recent years. This study focuses on the calculations of the absorbed doses of different parts of the eye using the stylized models located in UF-ORNL phantom and comparison with the data calculated with the reference computational phantom in a broad parallel beam incident of protons with energies between 20 MeV and 10 GeV. The obtained results indicate that the total lens absorbed doses of reference phantom has good compliance with those of the more sensitive regions of stylized models. However, total eye absorbed dose of these models greatly differ with each other for lower energies. - Highlights: • The validation of reference data for the eye was studied for proton exposures. • Two real mathematical models of the eye were imported into the UF-ORNL phantom. • Fluence to dose conversion coefficients were calculated for different eye sections. • Obtained Results were compared with that of assessed by ICRP adult male phantom

  1. Asymmetric-cut variable-incident-angle monochromator.

    Science.gov (United States)

    Smither, R K; Graber, T J; Fernandez, P B; Mills, D M

    2012-03-01

    A novel asymmetric-cut variable-incident-angle monochromator was constructed and tested in 1997 at the Advanced Photon Source of Argonne National Laboratory. The monochromator was originally designed as a high heat load monochromator capable of handling 5-10 kW beams from a wiggler source. This was accomplished by spreading the x-ray beam out on the surface an asymmetric-cut crystal and by using liquid metal cooling of the first crystal. The monochromator turned out to be a highly versatile monochromator that could perform many different types of experiments. The monochromator consisted of two 18° asymmetrically cut Si crystals that could be rotated about 3 independent axes. The first stage (Φ) rotates the crystal around an axis perpendicular to the diffraction plane. This rotation changes the angle of the incident beam with the surface of the crystal without changing the Bragg angle. The second rotation (Ψ) is perpendicular to the first and is used to control the shape of the beam footprint on the crystal. The third rotation (Θ) controls the Bragg angle. Besides the high heat load application, the use of asymmetrically cut crystals allows one to increase or decrease the acceptance angle for crystal diffraction of a monochromatic x-ray beam and allows one to increase or decrease the wavelength bandwidth of the diffraction of a continuum source like a bending-magnet beam or a normal x-ray-tube source. When the monochromator is used in the doubly expanding mode, it is possible to expand the vertical size of the double-diffracted beam by a factor of 10-15. When this was combined with a bending magnet source, it was possible to generate an 8 keV area beam, 16 mm wide by 26 mm high with a uniform intensity and parallel to 1.2 arc sec that could be applied in imaging experiments.

  2. Uniformity of the soft-x-ray emissions from gold foils irradiated by OMEGA laser beams determined by a two-mirror normal-incidence microscope with multilayer coatings

    International Nuclear Information System (INIS)

    Seely, John F.; Boehly, Thomas; Pien, Gregory; Bradley, David

    1998-01-01

    A two-mirror normal-incidence microscope with multilayer coatings was used to image the soft-x-ray emissions from planar foils irradiated by OMEGA laser beams. The bandpass of the multilayer coatings was centered at a wavelength of 48.3 Angstrom (257-eV energy) and was 0.5 Angstrom wide. Five overlapping OMEGA beams, without beam smoothing, were typically incident on the gold foils. The total energy was 1500 J, and the focused intensity was 6x10 13 Wcm -2 . The 5.8x magnified images were recorded by a gated framing camera at various times during the 3-ns laser pulse. A pinhole camera imaged the x-ray emission in the energy range of >2 keV. On a spatial scale of 10 μm, it was found that the soft-x-ray images at 257 eV were quite uniform and featureless. In contrast, the hard-x-ray images in the energy range of >2 kev were highly nonuniform with numerous features of size 150 μm. copyright 1998 Optical Society of America

  3. Resonance scattering of a dielectric sphere illuminated by electromagnetic Bessel non-diffracting (vortex) beams with arbitrary incidence and selective polarizations

    Energy Technology Data Exchange (ETDEWEB)

    Mitri, F.G., E-mail: F.G.Mitri@ieee.org [Chevron, Area 52 Technology–ETC, 5 Bisbee Ct., Santa Fe, NM 87508 (United States); Li, R.X., E-mail: rxli@mail.xidian.edu.cn [School of Physics and Optoelectronic Engineering, Xidian University, Xi’an 710071 (China); Collaborative Innovation Center of Information Sensing and Understanding, Xidian University, Xi’an 710071 (China); Guo, L.X. [School of Physics and Optoelectronic Engineering, Xidian University, Xi’an 710071 (China); Collaborative Innovation Center of Information Sensing and Understanding, Xidian University, Xi’an 710071 (China); Ding, C.Y. [School of Physics and Optoelectronic Engineering, Xidian University, Xi’an 710071 (China)

    2015-10-15

    A complete description of vector Bessel (vortex) beams in the context of the generalized Lorenz–Mie theory (GLMT) for the electromagnetic (EM) resonance scattering by a dielectric sphere is presented, using the method of separation of variables and the subtraction of a non-resonant background (corresponding to a perfectly conducting sphere of the same size) from the standard Mie scattering coefficients. Unlike the conventional results of standard optical radiation, the resonance scattering of a dielectric sphere in air in the field of EM Bessel beams is examined and demonstrated with particular emphasis on the EM field’s polarization and beam order (or topological charge). Linear, circular, radial, azimuthal polarizations as well as unpolarized Bessel vortex beams are considered. The conditions required for the resonance scattering are analyzed, stemming from the vectorial description of the EM field using the angular spectrum decomposition, the derivation of the beam-shape coefficients (BSCs) using the integral localized approximation (ILA) and Neumann–Graf’s addition theorem, and the determination of the scattering coefficients of the sphere using Debye series. In contrast with the standard scattering theory, the resonance method presented here allows the quantitative description of the scattering using Debye series by separating diffraction effects from the external and internal reflections from the sphere. Furthermore, the analysis is extended to include rainbow formation in Bessel beams and the derivation of a generalized formula for the deviation angle of high-order rainbows. Potential applications for this analysis include Bessel beam-based laser imaging spectroscopy, atom cooling and quantum optics, electromagnetic instrumentation and profilometry, optical tweezers and tractor beams, to name a few emerging areas of research.

  4. Experimental study of the molecular beam destruction by beam-beam and beam-background scattering

    International Nuclear Information System (INIS)

    Bossel, U.; Dettleff, G.

    1974-01-01

    The extraction of flow properties related to the molecular motion normal to stream lines of an expanding gas jet from observed intensity profiles of supersonic beams is critically assessed. The perturbation of the profile curves by various effects is studied for a helium beam. Exponential laws appear to describe scattering effects to a satisfactory degree

  5. Influence of the presence of tissue expanders on energy deposition for post-mastectomy radiotherapy.

    Directory of Open Access Journals (Sweden)

    Débora M Trombetta

    Full Text Available An increasing number of studies have shown that post-mastectomy radiotherapy presents benefits associated with the patients survival and a significant fraction of the treated patients makes use of tissue expanders for breast reconstruction. Some models of tissue expanders have a magnetic disk on their surface that constitutes heterogeneity in the radiation field, which can affect the dose distribution during the radiotherapy treatment. In this study, the influence of a metallic heterogeneity positioned in a breast tissue expander was evaluated by means of Monte Carlo simulations using the MCNPX code and using Eclipse treatment planning system. Deposited energy values were calculated in structures which have clinical importance for the treatment. Additionally, the effect in the absorbed energy due to backscattering and attenuation of the incident beam caused by the heterogeneity, as well as due to the expansion of the prosthesis, was evaluated in target structures for a 6 MV photon beam by simulations. The dose distributions for a breast treatment were calculated using a convolution/superposition algorithm from the Eclipse treatment planning system. When compared with the smallest breast expander volume, underdosage of 7% was found for the largest volume of breast implant, in the case of frontal irradiation of the chest wall, by Monte Carlo simulations. No significant changes were found in dose distributions for the presence of the heterogeneity during the treatment planning of irradiation with an opposed pair of beams. Even considering the limitation of the treatment planning system, the results obtained with its use confirm those ones found by Monte Carlo simulations for a tangent beam irradiation. The presence of a heterogeneity didn't alters the dose distributions on treatment structures. The underdosage of 7% observed with Monte Carlo simulations were found for irradiation at 0°, not used frequently in a clinical routine.

  6. Light scattering of a Bessel beam by a nucleated biological cell: An eccentric sphere model

    Science.gov (United States)

    Wang, Jia Jie; Han, Yi Ping; Chang, Jiao Yong; Chen, Zhu Yang

    2018-02-01

    Within the framework of generalized Lorenz-Mie theory (GLMT), an eccentrically stratified dielectric sphere model illuminated by an arbitrarily incident Bessel beam is applied to investigate the scattering characteristics of a single nucleated biological cell. The Bessel beam propagating in an arbitrary direction is expanded in terms of vector spherical wave functions (VSWFs), where the beam shape coefficients (BSCs) are calculated rigorously in a closed analytical form. The effects of the half-cone angle of Bessel beam, the location of the particle in the beam, the size ratio of nucleus to cell, and the location of the nucleus inside the cell on the scattering properties of a nucleated cell are analyzed. The results provide useful references for optical diagnostic and imaging of particle having nucleated structure.

  7. Production of muon pairs in the continuum region by 39.5 GeV/c π+-, K+-, p and anti p beams incident on a copper target

    International Nuclear Information System (INIS)

    Corden, M.J.; Dowell, J.D.; Eastwood, D.; Garvey, J.; Homer, R.J.; Jobes, M.; Kenyon, I.R.; McMahon, T.J.; Vallance, R.J.; Watkins, P.M.; Wilson, J.A.; Gago, J.; Jung, M.; Sonderegger, P.; Treille, D.; Woodworth, P.L.; Eckardt, V.; Fent, J.; Pretzl, K.; Seyboth, P.; Seyerlein, J.; Perrin, D.; Sumorok, K.C.T.O.

    1978-01-01

    General features of the inclusive hadroproduction of muon pairs of mass greater than 1.5 GeV/c 2 are shown. For incident π - , the data extend up to M = 5.7 GeV/c 2 (i.e. M 2 /s approximately 0.4). The scaling cross section M 3 dsigma/dM for π - N reaction is much flatter than that for pN reactions and exceeds the latter by two to three orders of magnitude at large M 2 /s. (Auth.)

  8. Statistical multifragmentation of non-spherical expanding sources in central heavy-ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Le Fevre, A. E-mail: a.lefevre@gsi.de; Ploszajczak, M.; Toneev, V.D.; Auger, G.; Begemann-Blaich, M.L.; Bellaize, N.; Bittiger, R.; Bocage, F.; Borderie, B.; Bougault, R.; Bouriquet, B.; Charvet, J.L.; Chbihi, A.; Dayras, R.; Durand, D.; Frankland, J.D.; Galichet, E.; Gourio, D.; Guinet, D.; Hudan, S.; Hurst, B.; Lautesse, P.; Lavaud, F.; Legrain, R.; Lopez, O.; Lukasik, J.; Lynen, U.; Mueller, W.F.J.; Nalpas, L.; Orth, H.; Plagnol, E.; Rosato, E.; Saija, A.; Schwarz, C.; Sfienti, C.; Tamain, B.; Trautmann, W.; Trzcinski, A.; Turzo, K.; Vient, E.; Vigilante, M.; Volant, C.; Zwieglinski, B.; Botvina, A.S

    2004-04-19

    We study the anisotropy effects measured with INDRA at GSI in central collisions of {sup 129}Xe+{sup nat}Sn at 50 A MeV and {sup 197}Au+{sup 197}Au at 60, 80, 100 A MeV incident energy. The microcanonical multifragmentation model with non-spherical sources is used to simulate an incomplete shape relaxation of the multifragmenting system. This model is employed to interpret observed anisotropic distributions in the fragment size and mean kinetic energy. The data can be well reproduced if an expanding prolate source aligned along the beam direction is assumed. An either non-Hubblean or non-isotropic radial expansion is required to describe the fragment kinetic energies and their anisotropy. The qualitative similarity of the results for the studied reactions suggests that the concept of a longitudinally elongated freeze-out configuration is generally applicable for central collisions of heavy systems. The deformation decreases slightly with increasing beam energy.

  9. Evidence for evanescent waves at interfaces in a high-index prism/liquid-crystal-Au-NPs/glass/air structure and effects of relative concentration of gold nanoparticles, wavelength, polarization, and incident angle of the laser beam

    Science.gov (United States)

    Tiwari, Kunal; Singh, Ankit; Sharma, Suresh

    2011-10-01

    Incorporation of relatively small concentrations of gold nanoparticles (Au NPs) in a polymer-dispersed liquid crystal (PDLC) is known to lower the operating threshold voltage and increase optical transmission through the device.ootnotetextA. Hinojosa and S. C. Sharma, Applied Physics Letters, 97, 081114 (2010) In order to understand whether there is an interplay between the localized surface plasmon resonance at Au-NPs-dielectric interfaces and the electro-optical properties of PDLC devices, we have investigated propagation of light through a high-index prism/liquid-crystal-Au-NPs/glass/air structure by using Kretschmann geometry as functions of concentration of Au NPs in the liquid crystal, and the wavelength, polarization, and angle of incidence of the laser beam. We will discuss to what extent the results of these experiments support an interplay between the localized surface plasmon resonance at NPs/dielectric interfaces and optical propagation through the above-described structure.

  10. What Expands in an Expanding Universe?

    Directory of Open Access Journals (Sweden)

    JOSÉ A. DE FREITAS PACHECO

    2015-12-01

    Full Text Available ABSTRACT In the present investigation, the possible effects of the expansion of the Universe on systems bonded either by gravitational or electromagnetic forces, are reconsidered. It will be shown that the acceleration (positive or negative of the expanding background, is the determinant factor affecting planetary orbits and atomic sizes. In the presently accepted cosmology (ΛCDM all bonded systems are expanding at a decreasing rate that tends to be zero as the universe enters in a de Sitter phase. It is worth mentioning that the estimated expansion rates are rather small and they can be neglected for all practical purposes.

  11. What Expands in an Expanding Universe?

    Science.gov (United States)

    Pacheco, José A De Freitas

    2015-01-01

    In the present investigation, the possible effects of the expansion of the Universe on systems bonded either by gravitational or electromagnetic forces, are reconsidered. It will be shown that the acceleration (positive or negative) of the expanding background, is the determinant factor affecting planetary orbits and atomic sizes. In the presently accepted cosmology (ΛCDM) all bonded systems are expanding at a decreasing rate that tends to be zero as the universe enters in a de Sitter phase. It is worth mentioning that the estimated expansion rates are rather small and they can be neglected for all practical purposes.

  12. Improving x-ray fluorescence signal for benchtop polychromatic cone-beam x-ray fluorescence computed tomography by incident x-ray spectrum optimization: a Monte Carlo study.

    Science.gov (United States)

    Manohar, Nivedh; Jones, Bernard L; Cho, Sang Hyun

    2014-10-01

    To develop an accurate and comprehensive Monte Carlo (MC) model of an experimental benchtop polychromatic cone-beam x-ray fluorescence computed tomography (XFCT) setup and apply this MC model to optimize incident x-ray spectrum for improving production/detection of x-ray fluorescence photons from gold nanoparticles (GNPs). A detailed MC model, based on an experimental XFCT system, was created using the Monte Carlo N-Particle (MCNP) transport code. The model was validated by comparing MC results including x-ray fluorescence (XRF) and scatter photon spectra with measured data obtained under identical conditions using 105 kVp cone-beam x-rays filtered by either 1 mm of lead (Pb) or 0.9 mm of tin (Sn). After validation, the model was used to investigate the effects of additional filtration of the incident beam with Pb and Sn. Supplementary incident x-ray spectra, representing heavier filtration (Pb: 2 and 3 mm; Sn: 1, 2, and 3 mm) were computationally generated and used with the model to obtain XRF/scatter spectra. Quasimonochromatic incident x-ray spectra (81, 85, 90, 95, and 100 keV with 10 keV full width at half maximum) were also investigated to determine the ideal energy for distinguishing gold XRF signal from the scatter background. Fluorescence signal-to-dose ratio (FSDR) and fluorescence-normalized scan time (FNST) were used as metrics to assess results. Calculated XRF/scatter spectra for 1-mm Pb and 0.9-mm Sn filters matched (r ≥ 0.996) experimental measurements. Calculated spectra representing additional filtration for both filter materials showed that the spectral hardening improved the FSDR at the expense of requiring a much longer FNST. In general, using Sn instead of Pb, at a given filter thickness, allowed an increase of up to 20% in FSDR, more prominent gold XRF peaks, and up to an order of magnitude decrease in FNST. Simulations using quasimonochromatic spectra suggested that increasing source x-ray energy, in the investigated range of 81-100 ke

  13. Improving x-ray fluorescence signal for benchtop polychromatic cone-beam x-ray fluorescence computed tomography by incident x-ray spectrum optimization: A Monte Carlo study

    Science.gov (United States)

    Manohar, Nivedh; Jones, Bernard L.; Cho, Sang Hyun

    2014-01-01

    Purpose: To develop an accurate and comprehensive Monte Carlo (MC) model of an experimental benchtop polychromatic cone-beam x-ray fluorescence computed tomography (XFCT) setup and apply this MC model to optimize incident x-ray spectrum for improving production/detection of x-ray fluorescence photons from gold nanoparticles (GNPs). Methods: A detailed MC model, based on an experimental XFCT system, was created using the Monte Carlo N-Particle (MCNP) transport code. The model was validated by comparing MC results including x-ray fluorescence (XRF) and scatter photon spectra with measured data obtained under identical conditions using 105 kVp cone-beam x-rays filtered by either 1 mm of lead (Pb) or 0.9 mm of tin (Sn). After validation, the model was used to investigate the effects of additional filtration of the incident beam with Pb and Sn. Supplementary incident x-ray spectra, representing heavier filtration (Pb: 2 and 3 mm; Sn: 1, 2, and 3 mm) were computationally generated and used with the model to obtain XRF/scatter spectra. Quasimonochromatic incident x-ray spectra (81, 85, 90, 95, and 100 keV with 10 keV full width at half maximum) were also investigated to determine the ideal energy for distinguishing gold XRF signal from the scatter background. Fluorescence signal-to-dose ratio (FSDR) and fluorescence-normalized scan time (FNST) were used as metrics to assess results. Results: Calculated XRF/scatter spectra for 1-mm Pb and 0.9-mm Sn filters matched (r ≥ 0.996) experimental measurements. Calculated spectra representing additional filtration for both filter materials showed that the spectral hardening improved the FSDR at the expense of requiring a much longer FNST. In general, using Sn instead of Pb, at a given filter thickness, allowed an increase of up to 20% in FSDR, more prominent gold XRF peaks, and up to an order of magnitude decrease in FNST. Simulations using quasimonochromatic spectra suggested that increasing source x-ray energy, in the

  14. Beam Profile Measurement in MTA Beam Line for High Pressure RF Cavity Beam Test

    International Nuclear Information System (INIS)

    Jana, M.R.; Bross, A.; Chung, M.; Greer, S.; Johnstone, C.; Kobilarcik, T.; Koizumi, G.; Leonova, M.; Moretti, A.; Popovic, M.; Schwartz, T.

    2012-01-01

    Recent High Pressure RF (HPRF) cavity experiment at MuCool Test Area (MTA) has used 400 MeV Linac proton beam to study the beam loading effect. When the energetic proton beam passes through the cavity, it ionizes the inside gas and produces the electrons. These electrons consume RF power inside the cavity. Number of electrons produced per cm inside the cavity (at 950 psi Hydrogen gas) per incident proton is ∼ 1200. The measurement of beam position and profile are necessary. MTA is flammable gas (Hydrogen) hazard zone so we have developed a passive beam diagnostic instrument using Chromox-6 scintillation screen and CCD camera. This paper presents quantitative information about beam position and beam profile. Neutral density filter was used to avoid saturation of CCD camera. Image data is filtered and fitted with Gaussian function to compute the beam size. The beam profile obtained from scintillation screen shall be compared with multi-wire beam profile.

  15. Layouts of Expander Graphs

    OpenAIRE

    Dujmović, Vida; Sidiropoulos, Anastasios; Wood, David R.

    2015-01-01

    Bourgain and Yehudayoff recently constructed $O(1)$-monotone bipartite expanders. By combining this result with a generalisation of the unraveling method of Kannan, we construct 3-monotone bipartite expanders, which is best possible. We then show that the same graphs admit 3-page book embeddings, 2-queue layouts, 4-track layouts, and have simple thickness 2. All these results are best possible.

  16. Photon collider beam simulation with CAIN

    Indian Academy of Sciences (India)

    the laser pulse and the beam–beam interaction, is presented in figure 1. Energy flow obtained from the simulation was scaled to the average beam power. After the. Compton scattering, most of the incident electron beam power is transfered to the photon beam. However, the high-energy photons are very well-collimated ...

  17. Functionalized expanded porphyrins

    Science.gov (United States)

    Sessler, Jonathan L; Pantos, Patricia J

    2013-11-12

    Disclosed are functionalized expanded porphyrins that can be used as spectrometric sensors for high-valent actinide cations. The disclosed functionalized expanded porphyrins have the advantage over unfunctionalized systems in that they can be immobilized via covalent attachment to a solid support comprising an inorganic or organic polymer or other common substrates. Substrates comprising the disclosed functionalized expanded porphyrins are also disclosed. Further, disclosed are methods of making the disclosed compounds (immobilized and free), methods of using them as sensors to detect high valent actinides, devices that comprise the disclosed compounds, and kits.

  18. Controlling Second Harmonic Efficiency of Laser Beam Interactions

    Science.gov (United States)

    Barnes, Norman P. (Inventor); Walsh, Brian M. (Inventor); Reichle, Donald J. (Inventor)

    2011-01-01

    A method is provided for controlling second harmonic efficiency of laser beam interactions. A laser system generates two laser beams (e.g., a laser beam with two polarizations) for incidence on a nonlinear crystal having a preferred direction of propagation. Prior to incidence on the crystal, the beams are optically processed based on the crystal's beam separation characteristics to thereby control a position in the crystal along the preferred direction of propagation at which the beams interact.

  19. Expanding Thurston maps

    CERN Document Server

    Bonk, Mario

    2017-01-01

    This monograph is devoted to the study of the dynamics of expanding Thurston maps under iteration. A Thurston map is a branched covering map on a two-dimensional topological sphere such that each critical point of the map has a finite orbit under iteration. It is called expanding if, roughly speaking, preimages of a fine open cover of the underlying sphere under iterates of the map become finer and finer as the order of the iterate increases. Every expanding Thurston map gives rise to a fractal space, called its visual sphere. Many dynamical properties of the map are encoded in the geometry of this visual sphere. For example, an expanding Thurston map is topologically conjugate to a rational map if and only if its visual sphere is quasisymmetrically equivalent to the Riemann sphere. This relation between dynamics and fractal geometry is the main focus for the investigations in this work.

  20. Expanding mediation theory

    NARCIS (Netherlands)

    Verbeek, Peter P.C.C.

    2012-01-01

    In his article In Between Us, Yoni van den Eede expands existing theories of mediation into the realm of the social and the political, focusing on the notions of opacity and transparency. His approach is rich and promising, but two pitfalls should be avoided. First, his concept of ‘in-between’ runs

  1. Wheelchair incidents

    NARCIS (Netherlands)

    Drongelen AW van; Roszek B; Hilbers-Modderman ESM; Kallewaard M; Wassenaar C; LGM

    2002-01-01

    This RIVM study was performed to gain insight into wheelchair-related incidents with powered and manual wheelchairs reported to the USA FDA, the British MDA and the Dutch Center for Quality and Usability Research of Technical Aids (KBOH). The data in the databases do not indicate that incidents with

  2. Transverse beam shape measurements of intense proton beams using optical transition radiation

    Energy Technology Data Exchange (ETDEWEB)

    Scarpine, Victor E.; /Fermilab

    2012-03-01

    A number of particle physics experiments are being proposed as part of the Department of Energy HEP Intensity Frontier. Many of these experiments will utilize megawatt level proton beams onto targets to form secondary beams of muons, kaons and neutrinos. These experiments require transverse size measurements of the incident proton beam onto target for each beam spill. Because of the high power levels, most beam intercepting profiling techniques will not work at full beam intensity. The possibility of utilizing optical transition radiation (OTR) for high intensity proton beam profiling is discussed. In addition, previous measurements of OTR beam profiles from the NuMI beamline are presented.

  3. Coherent beam-beam effects

    International Nuclear Information System (INIS)

    Chao, A.W.

    1992-01-01

    There are two physical pictures that describe the beam-beam interaction in a storage ring collider: The weak-strong and the strong-strong pictures. Both pictures play a role in determining the beam-beam behavior. This review addresses only the strong-strong picture. The corresponding beam dynamical effects are referred to as the coherent beam-beam effects. Some basic knowledge of the weak-strong picture is assumed. To be specific, two beams of opposite charges are considered. (orig.)

  4. Expandable LED array interconnect

    Science.gov (United States)

    Yuan, Thomas Cheng-Hsin; Keller, Bernd

    2011-03-01

    A light emitting device that can function as an array element in an expandable array of such devices. The light emitting device comprises a substrate that has a top surface and a plurality of edges. Input and output terminals are mounted to the top surface of the substrate. Both terminals comprise a plurality of contact pads disposed proximate to the edges of the substrate, allowing for easy access to both terminals from multiple edges of the substrate. A lighting element is mounted to the top surface of the substrate. The lighting element is connected between the input and output terminals. The contact pads provide multiple access points to the terminals which allow for greater flexibility in design when the devices are used as array elements in an expandable array.

  5. Short Rayleigh Length Free Electron Laser Simulations in Expanding Coordinates

    CERN Document Server

    Armstead, Robert L; Colson, William B

    2004-01-01

    For compact short-Rayleigh length FELs, the area of the optical beam can be thousands of times greater at the mirrors than at the beam waist. A fixed numerical grid of sufficient resolution to represent the narrow mode at the waist and the broad mode at the mirrors would be prohibitively large. To accommodate this extreme change of scale with no loss of information, we employ a coordinate system that expands with the diffracting optical mode. The simulation using the new expanding coordinates has been validated by comparison to analytical cold-cavity theory, and is now used to simulate short-Rayleigh length FELs.

  6. Expanding the HAWC Observatory

    Energy Technology Data Exchange (ETDEWEB)

    Mori, Johanna [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-17

    The High Altitude Water Cherenkov Gamma-Ray Observatory is expanding its current array of 300 water tanks to include 350 outrigger tanks to increase sensitivity to gamma rays above 10 TeV. This involves creating and testing hardware with which to build the new tanks, including photomultiplier tubes, high voltage supply units, and flash analog to digital converters. My responsibilities this summer included preparing, testing and calibrating that equipment.

  7. Superresolution beams

    CSIR Research Space (South Africa)

    Ngcobo, S

    2011-11-01

    Full Text Available zones capable of introducing a phase shift of zero or p on the alternately out of phase rings of the TEMp0 beams into a unified phase and then focusing the rectified beam to generate a high resolution beam which has a Gaussian beam intensity distribution...

  8. Expanding Your Horizon 2015

    CERN Multimedia

    Kaltenhauser, Kristin

    2015-01-01

    Expanding your horizons is a bi-annual “Science Day” for girls aged 11 to 14, held at the University of Geneva on 14 November. The girls had the opportunity to take part in hands-on workshops held by local professional women in the field of science, mathematics, engineering and technology. For the fourth time, CERN was part of this event, offering three workshops as well as a booth at the Discovery Fair, including Higgnite, an interactive visualization of the Higgs Field.

  9. The expanding universe

    CERN Document Server

    Lew, Kristi

    2011-01-01

    People have always been fascinated with the stars above and the universe that contains them. Over the years, astronomers have developed numerous theories to explain how the universe began, how it works, and what its ultimate fate will be. But all of the scientists' questions are far from answered. The Expanding Universe goes beyond the creation of the universe to explain how scientists think the universe works, grows, and changes, including what great thinkers Isaac Newton and Albert Einstein had to say about its fate. Readers will also learn about how researchers are slowly shedding light on

  10. Beam-beam and impedance

    CERN Document Server

    White, S.

    2014-07-17

    As two counter-rotating beams interact they can give rise to coherent dipole modes. Under the influence of impedance these coherent beam-beam modes can couple to higher order head-tail modes and lead to strong instabilities. A fully self-consistent approach including beam-beam and impedance was used to characterize this new coupled mode instability and study possible cures such as a transverse damper and high chromaticity.

  11. Data transfer through beam steering using agile lensing

    Science.gov (United States)

    Arshad, Muhammad Assad; Reza, Syed Azer; Muhammad, Ahsan

    2016-04-01

    This paper presents a data transfer scheme using multi-focus tunable lenses. The design involves the use of a standard laser source and a variable focus agile lens to steer to the laser beam that passes through the lens. In our proposed system, the beam steer angle depends on an input electrical signal which drives the tunable lens. Therefore the beam steer angle is made to follow the variations in the input electrical drive signal. This is extremely interesting for data transfer applications as the data signal can be used as the input drive signal to the lens. The laser beam is steered according to the input data voltage levels and when the beam is incident on a photo-detector of a finite size, only a fraction of its total incident optical power is received by the photo-detector. This power contribution is proportional to the fraction of the total number of photons per unit area which are incident on the active area of the detector. The remaining photons which are not incident on the photo-detector do not contribute to the received power at the photo-detector. We present the theory of beam steering through a tunable lens and present a theoretical framework which governs data transfer through the proposed method. We also present the transfer function of the proposed system which helps us to calculate its essential theoretical performance parameters such as modulation depth and bit error rates. We also present experimental results to demonstrate efficient data transfer through the proposed method. As tunable lenses are primarily deployed in motion-free multi-focus cameras hence most of the modern portable devices such as cellphones and tablets use these lenses to operate the in-built variable focus cameras that are part of these devices. Because tunable lenses are commonly present in several different portable devices, the proposed method of data transfer between two devices is highly promising as it expands the use of the already deployed tunable lenses with

  12. Incidents analysis

    International Nuclear Information System (INIS)

    Francois, P.

    1996-01-01

    We undertook a study programme at the end of 1991. To start with, we performed some exploratory studies aimed at learning some preliminary lessons on this type of analysis: Assessment of the interest of probabilistic incident analysis; possibility of using PSA scenarios; skills and resources required. At the same time, EPN created a working group whose assignment was to define a new approach for analysis of incidents on NPPs. This working group gave thought to both aspects of Operating Feedback that EPN wished to improve: Analysis of significant incidents; analysis of potential consequences. We took part in the work of this group, and for the second aspects, we proposed a method based on an adaptation of the event-tree method in order to establish a link between existing PSA models and actual incidents. Since PSA provides an exhaustive database of accident scenarios applicable to the two most common types of units in France, they are obviously of interest for this sort of analysis. With this method we performed some incident analyses, and at the same time explores some methods employed abroad, particularly ASP (Accident Sequence Precursor, a method used by the NRC). Early in 1994 EDF began a systematic analysis programme. The first, transient phase will set up methods and an organizational structure. 7 figs

  13. Factors leading to tracheobronchial self-expandable metallic stent fracture.

    Science.gov (United States)

    Chung, Fu-Tsai; Lin, Shu-Min; Chen, Hao-Cheng; Chou, Chun-Liang; Yu, Chih-Teng; Liu, Chien-Ying; Wang, Chun-Hua; Lin, Horng-Chyuan; Huang, Chien-Da; Kuo, Han-Pin

    2008-11-01

    This retrospective study was to determine factors that contribute to self-expandable metallic stent fracture in patients with tracheobronchial disease. From 2001 to 2006, 139 patients (age, 62.1 +/- 15.4 years; range, 23-87 years) with benign (n = 62) and malignant (n = 77) tracheobronchial disease received 192 Ultraflex (Boston Scientific, Natick, Mass) self-expandable metallic stents (98 in patients with benign disease and 94 in patients with malignant disease). Seventeen fractured self-expandable metallic stents were found; the incidence was 12.2% (17/139 patients) among patients with tracheobronchial disease. Tortuous airway (odds ratio, 4.06; 95% confidence interval, 1.04-18.34; P = .04) independently predicted self-expandable metallic stent fracture. Most self-expandable metallic stent fractures (64.7%, 11/17) were detected 500 to 1000 days after self-expandable metallic stent implantation. Clinical presentations for patients with fractured self-expandable metallic stents included dyspnea exacerbation (70.6%, 12/17) and cough (23.5%, 4/17). Self-expandable metallic stent fracture is not uncommon in patients with tracheobronchial disease. Tortuous airway is an independent predictor for it. Although management of the fractured self-expandable metallic stent in our study was feasible and safe, self-expandable metallic stents should be restricted to a more select population.

  14. Tissue expander infections in children: look beyond the expander pocket.

    Science.gov (United States)

    Mason, A C; Davison, S P; Manders, E K

    1999-11-01

    Infection of the expander pocket is the most common complication encountered with soft-tissue expansion. It is usually due to direct inoculation with skin flora either at the time of expander insertion or from extrusion of the device. The authors report two cases of infection of tissue expanders in which the children had concomitant infected sites distant from the prosthesis. Etiological bacteria of common pediatric infections like otitis media and pharyngitis were cultured from the infected expander pocket, raising suspicion that translocation of the organism to the expander had occurred. Aggressive antibiotic treatment, removal of the prosthesis, and flap advancement is advocated.

  15. Expanding hollow metal rings

    Science.gov (United States)

    Peacock, Harold B [Evans, GA; Imrich, Kenneth J [Grovetown, GA

    2009-03-17

    A sealing device that may expand more planar dimensions due to internal thermal expansion of a filler material. The sealing material is of a composition such that when desired environment temperatures and internal actuating pressures are reached, the sealing materials undergoes a permanent deformation. For metallic compounds, this permanent deformation occurs when the material enters the plastic deformation phase. Polymers, and other materials, may be using a sealing mechanism depending on the temperatures and corrosivity of the use. Internal pressures are generated by either rapid thermal expansion or material phase change and may include either liquid or solid to gas phase change, or in the gaseous state with significant pressure generation in accordance with the gas laws. Sealing material thickness and material composition may be used to selectively control geometric expansion of the seal such that expansion is limited to a specific facing and or geometric plane.

  16. Expandable pattern casting research

    Science.gov (United States)

    1993-09-01

    The Expandable Pattern Casting (EPC) Process is a developing foundry technology that allows designers the opportunity to consolidate parts, reduce machining, and minimize assembly operations. An air gauging system was developed for measuring foam patterns; exact shrinkage depended on type and density of the foam. Compaction studies showed that maximum sand densities in cavities and under overhangs are achieved with vibrational amplitudes 0.001-0.004 in., and that sand moved most freely within a few inches of the top free surface. Key to complete mold filling while minimizing casting defects lies in removing the foam decomposition products. The most precise iron castings were made by EPC in four commercial EPC foundries, with attention paid to molding and compaction. EP cast 60-45-12 ductile iron had yield strengths, ultimate strengths, and elastic modulus similar to conventionally cast ductile iron cast from the same ladle.

  17. Expanding or postponing?

    DEFF Research Database (Denmark)

    Jensen, Tanja Dall; Caswell, Dorte

    2017-01-01

    setting. Working with data from 97 team meetings in a social work setting, we identify two patterns of negotiation in talk; expanding and postponing. ‘Expanding’ covers a group of interactional actions involving turn-taking and closure, while ‘postponing’ includes a group of actions whereby assessments......In this paper, we examine patterns of negotiation in multi-party interaction in social work. We draw on Strauss’ theory of negotiated order and a conversation analytical approach, seeking to gain insight into the complex accomplishment of making a decision in an inter-professional and multiparty...... or topics are avoided or made irrelevant. Both are examples of the complex ways in which team members negotiate both the institutional order and the decision to be made in the specific case in situ....

  18. Beam cooling

    OpenAIRE

    Danared, H

    2006-01-01

    Beam cooling is the technique of reducing the momentum spread and increasing the phase-space density of stored particle beams. This paper gives an introduction to beam cooling and Liouville’s theorem, and then it describes the three methods of active beam cooling that have been proven to work so far, namely electron cooling, stochastic cooling, and laser cooling. Ionization cooling is also mentioned briefly.

  19. Molecular beams

    International Nuclear Information System (INIS)

    Pendelbury, J.M.; Smith, K.F.

    1987-01-01

    Studies with directed collision-free beams of particles continue to play an important role in the development of modern physics and chemistry. The deflections suffered by such beams as they pass through electric and magnetic fields or laser radiation provide some of the most direct information about the individual constituents of the beam; the scattering observed when two beams intersect yields important data about the intermolecular forces responsible for the scattering. (author)

  20. Funnel cone for focusing intense ion beams on a target

    International Nuclear Information System (INIS)

    Bieniosek, F.M.; Henestroza, E.; Ni, P.

    2009-01-01

    We describe a funnel cone for concentrating an ion beam on a target. The cone utilizes the reflection characteristic of ion beams on solid walls to focus the incident beam andincrease beam intensity on target. The cone has been modeled with the TRIM code. A prototype has been tested and installed for use in the 350-keV K+ NDCX target chamber.

  1. Photon beam position monitor

    Science.gov (United States)

    Kuzay, Tuncer M.; Shu, Deming

    1995-01-01

    A photon beam position monitor for use in the front end of a beamline of a high heat flux and high energy photon source such as a synchrotron radiation storage ring detects and measures the position and, when a pair of such monitors are used in tandem, the slope of a photon beam emanating from an insertion device such as a wiggler or an undulator inserted in the straight sections of the ring. The photon beam position monitor includes a plurality of spaced blades for precisely locating the photon beam, with each blade comprised of chemical vapor deposition (CVD) diamond with an outer metal coating of a photon sensitive metal such as tungsten, molybdenum, etc., which combination emits electrons when a high energy photon beam is incident upon the blade. Two such monitors are contemplated for use in the front end of the beamline, with the two monitors having vertically and horizontally offset detector blades to avoid blade "shadowing". Provision is made for aligning the detector blades with the photon beam and limiting detector blade temperature during operation.

  2. The Artful Universe Expanded

    Energy Technology Data Exchange (ETDEWEB)

    Bassett, B A [Institute of Cosmology and Gravitation, University of Portsmouth (United Kingdom)

    2005-07-29

    The cosmos is an awfully big place and there is no better guide to its vast expanse and fascinating nooks and crannies than John Barrow. A professor of mathematical sciences at Cambridge University, Barrow embodies that rare combination of highly polished writer and expert scientist. His deft touch brings together the disparate threads of human knowledge and weaves them into a tapestry as rich and interesting for the expert as it is for the layperson. The Artful Universe Expanded is an updated edition of this popular book first published in 1995. It explores the deeply profound manner in which natural law and the nature of the cosmos have moulded and shaped us, our cultures and the very form of our arts and music-a new type of 'cosmic' anthropology. The main themes Barrow chooses for revealing this new anthropology are the subjects of evolution, the size of things, the heavens and the nature of music. The book is a large, eclectic repository of knowledge often unavailable to the layperson, hidden in esoteric libraries around the world. It rivals The Da Vinci Code for entertainment value and insights, but this time it is Nature's code that is revealed. It is rare indeed to find common threads drawn through topics as diverse as The Beetles, Bach and Beethoven or between Jackson Pollock, the Aztecs, Kant, Picasso, Byzantine mosaics, uranium-235 and the helix nebula. Barrow unerringly binds them together, presenting them in a stimulating, conversational style that belies the amount of time that must have gone into researching this book. Dip into it at random, or read it from cover to cover, but do read it. The Artful Universe Expanded is an entertaining antidote to the oft-lamented pressures to know more and more about less and less and the apparently inexorable march of specialization. On reading this book one can, for a short time at least, hold in one's mind a vision that unifies science, art and culture and glimpse a universal tapestry of great

  3. The Artful Universe Expanded

    International Nuclear Information System (INIS)

    Bassett, B A

    2005-01-01

    The cosmos is an awfully big place and there is no better guide to its vast expanse and fascinating nooks and crannies than John Barrow. A professor of mathematical sciences at Cambridge University, Barrow embodies that rare combination of highly polished writer and expert scientist. His deft touch brings together the disparate threads of human knowledge and weaves them into a tapestry as rich and interesting for the expert as it is for the layperson. The Artful Universe Expanded is an updated edition of this popular book first published in 1995. It explores the deeply profound manner in which natural law and the nature of the cosmos have moulded and shaped us, our cultures and the very form of our arts and music-a new type of 'cosmic' anthropology. The main themes Barrow chooses for revealing this new anthropology are the subjects of evolution, the size of things, the heavens and the nature of music. The book is a large, eclectic repository of knowledge often unavailable to the layperson, hidden in esoteric libraries around the world. It rivals The Da Vinci Code for entertainment value and insights, but this time it is Nature's code that is revealed. It is rare indeed to find common threads drawn through topics as diverse as The Beetles, Bach and Beethoven or between Jackson Pollock, the Aztecs, Kant, Picasso, Byzantine mosaics, uranium-235 and the helix nebula. Barrow unerringly binds them together, presenting them in a stimulating, conversational style that belies the amount of time that must have gone into researching this book. Dip into it at random, or read it from cover to cover, but do read it. The Artful Universe Expanded is an entertaining antidote to the oft-lamented pressures to know more and more about less and less and the apparently inexorable march of specialization. On reading this book one can, for a short time at least, hold in one's mind a vision that unifies science, art and culture and glimpse a universal tapestry of great beauty. (book review)

  4. Beam diagnostics

    International Nuclear Information System (INIS)

    Bogaty, J.; Clifft, B.E.; Zinkann, G.P.; Pardo, R.C.

    1995-01-01

    The ECR-PII injector beam line is operated at a fixed ion velocity. The platform high voltage is chosen so that all ions have a velocity of 0.0085c at the PII entrance. If a previous tune configuration for the linac is to be used, the beam arrival time must be matched to the previous tune as well. A nondestructive beam-phase pickup detector was developed and installed at the entrance to the PII linac. This device provides continuous phase and beam current information and allows quick optimization of the beam injected into PII. Bunches traverse a short tubular electrode thereby inducing displacement currents. These currents are brought outside the vacuum interface where a lumped inductance resonates electrode capacitance at one of the bunching harmonic frequencies. This configuration yields a basic sensitivity of a few hundred millivolts signal per microampere of beam current. Beam-induced radiofrequency signals are summed against an offset frequency generated by our master oscillator. The resulting kilohertz difference frequency conveys beam intensity and bunch phase information which is sent to separate processing channels. One channel utilizes a phase locked loop which stabilizes phase readings if beam is unstable. The other channel uses a linear full wave active rectifier circuit which converts kilohertz sine wave signal amplitude to a D.C. voltage representing beam current. A prototype set of electronics is now in use with the detector and we began to use the system in operation to set the arrival beam phase. A permanent version of the electronics system for the phase detector is now under construction. Additional nondestructive beam intensity and phase monitors at the open-quotes Boosterclose quotes and open-quotes ATLASclose quotes linac sections are planned as well as on some of the high-energy beam lines. Such a monitor will be particularly useful for FMA experiments where the primary beam hits one of the electric deflector plates

  5. The Artful Universe Expanded

    Science.gov (United States)

    Barrow, John D.

    2005-07-01

    Our love of art, writes John Barrow, is the end product of millions of years of evolution. How we react to a beautiful painting or symphony draws upon instincts laid down long before humans existed. Now, in this enhanced edition of the highly popular The Artful Universe , Barrow further explores the close ties between our aesthetic appreciation and the basic nature of the Universe. Barrow argues that the laws of the Universe have imprinted themselves upon our thoughts and actions in subtle and unexpected ways. Why do we like certain types of art or music? What games and puzzles do we find challenging? Why do so many myths and legends have common elements? In this eclectic and entertaining survey, Barrow answers these questions and more as he explains how the landscape of the Universe has influenced the development of philosophy and mythology, and how millions of years of evolutionary history have fashioned our attraction to certain patterns of sound and color. Barrow casts the story of human creativity and thought in a fascinating light, considering such diverse topics as our instinct for language, the origins and uses of color in nature, why we divide time into intervals as we do, the sources of our appreciation of landscape painting, and whether computer-generated fractal art is really art. Drawing on a wide variety of examples, from the theological questions raised by St. Augustine and C.S. Lewis to the relationship between the pure math of Pythagoras and the music of the Beatles, The Artful Universe Expanded covers new ground and enters a wide-ranging debate about the meaning and significance of the links between art and science.

  6. Elliptical beams.

    Science.gov (United States)

    Bandres, Miguel A; Gutiérrez-Vega, Julio C

    2008-12-08

    A very general beam solution of the paraxial wave equation in elliptic cylindrical coordinates is presented. We call such a field an elliptic beam (EB). The complex amplitude of the EB is described by either the generalized Ince functions or the Whittaker-Hill functions and is characterized by four parameters that are complex in the most general situation. The propagation through complex ABCD optical systems and the conditions for square integrability are studied in detail. Special cases of the EB are the standard, elegant, and generalized Ince-Gauss beams, Mathieu-Gauss beams, among others.

  7. Bigelow Expandable Activity Module Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The BEAM project advances inflatable habitat technology further and conducts flight demonstration of a commercially-designed inflatable system to achieve Technology...

  8. The Expanding Universe: Dark Energy

    Energy Technology Data Exchange (ETDEWEB)

    Lincoln, Don [Fermilab; Nord, Brian [Fermilab

    2014-09-01

    In 1998, observations of distant supernovae led physicists that not only was the universe expanding, but the expansion was speeding up. In this article, we describe the evidence for an expanding universe and describe what physicists and cosmologists have learned in the intervening years. The target audience for this article is high school physics teachers and college physics professors at teaching institutions.

  9. Superresolution beams

    CSIR Research Space (South Africa)

    Ngcobo, S

    2012-07-01

    Full Text Available positions of p zeros of intensity distributions on the Gaussian beam, resulting to a generation of TEMp0 beams where there are minimum losses. The LGBs are well-known family of exact orthogonal solutions of free-space paraxial wave equation in cylindrical...

  10. The effect of laser beam size in a zig-zag collimator on transverse ...

    Indian Academy of Sciences (India)

    The effect of size of a cooling laser beam in a zig-zag atomic beam collimator on transverse cooling of a krypton atomic beam is investigated. The simulation results show that discreteness in the interaction between the cooling laser beam and atomic beam, arising due to finite size and incidence angle of the cooling laser ...

  11. RIKEN RI Beam Factory project

    Energy Technology Data Exchange (ETDEWEB)

    Yano, Yasushige; Goto, Akira; Katayama, Takeshi [Institute of Physical and Chemical Research, Wako, Saitama (Japan)

    1997-03-01

    The RARF proposes `RIKEN RI Beam Factory` as a next facility-expanding project. The factory makes it the primary aim to provide RI (Radioactive Isotope) beams covering over the whole atomic-mass range with the world-highest intensity in a wide energy range up to several hundreds MeV/nucleon. These RI beams are generated by the fragmentation of high-intensity heavy-ion beams. For the efficient production heavy-ion energies will be boosted up to over 100 MeV/nucleon even for very heavy ions by a K2500-MeV superconducting ring cyclotron serving as a post accelerator of the existing K540-MeV ring cyclotron. A new type of experimental installation called `MUSES` (Multi-USe Experimental Storage rings) will be constructed as well. With MUSES, various types of unique colliding experiments will become possible. (author)

  12. Beam diagnostics

    CERN Document Server

    Raich, U

    2008-01-01

    Most beam measurements are based on the electro-magnetic interaction of fields induced by the beam with their environment. Beam current transformers as well as beam position monitors are based on this principle. The signals induced in the sensors must be amplified and shaped before they are converted into numerical values. These values are further treated numerically in order to extract meaningful machine parameter measurements. The lecture introduces the architecture of an instrument and shows where in the treatment chain digital signal analysis can be introduced. Then the use of digital signal processing is presented using tune measurements, orbit and trajectory measurements as well as beam loss detection and longitudinal phase space tomography as examples. The hardware as well as the treatment algorithms and their implementation on Digital Signal Processors (DSPs) or in Field Programmable Gate Arrays (FPGAs) are presented.

  13. Particles formation in an expanding plasma

    Energy Technology Data Exchange (ETDEWEB)

    Lescoute, E.; Hallo, L.; Chimier, B.; Tikhonchuk, V.T.; Stenz, C. [Bordeaux-1 Univ., CELIA, CNRS-CEA, 33 - Talence (France); Hebert, D.; Chevalier, J.M.; Rullier, J.L.; Palmier, S. [CEA Centre d' Etudes Scientifiques et Techniques d' Aquitaine, 33 - Le Barp (France)

    2009-08-15

    Interaction of a laser beam with a target generates a high velocity expanding plasma plume, solid debris and liquid nano- and micro-particles. They are produced from plasma recombination and vapor condensation and can be deposited on optical elements located nearby the target. Two distinct kinds of particles were observed depending on the temperature achieved in the plasma plume: large micrometer-size fragments for temperatures lower than the critical temperature, and very small nanometer-size particles for higher temperatures. The paper presents experimental observations of fragments and nano-particles in plasma plumes and a comparison with models. A good agreement has been found for nano-particle sizes and distributions. This simple modeling can also be used for nuclei production in the nanosecond time scale. Our estimates show that particle size can be correlated to laser wavelength and fluences.

  14. Acoustic radiation force on a sphere in a progressive and standing zero-order quasi-Bessel-Gauss beam.

    Science.gov (United States)

    Jiang, Chen; Liu, Xiaozhou; Liu, Jiehui; Mao, Yiwei; Marston, Philip L

    2017-04-01

    By means of series expansion theory, the incident quasi-Bessel-Gauss beam is expanded using spherical harmonic functions, and the beam coefficients of the quasi-Bessel-Gauss beam are calculated. According to the theory, the acoustic radiation force function, which is the radiation force per unit energy on a unit cross-sectional surface on a sphere made of diverse materials and immersed in an ideal fluid along the propagation axis of zero-order quasi-Bessel-Gauss progressive and standing beams, is investigated. The acoustic radiation force function is calculated as a function of the spherical radius parameter ka and the half-cone angle β with different beam widths in a progressive and standing zero-order Bessel-Gauss beam. Simulation results indicate that the acoustic radiation forces with different waist radii demonstrate remarkably different features from those found in previous studies. The results are expected to be useful in potential applications such as acoustic tweezers. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Gaussian beam shooting algorithm based on iterative frame decomposition

    OpenAIRE

    Ghannoum, Ihssan; Letrou, Christine; Beauquet, Gilles

    2010-01-01

    International audience; Adaptive beam re-shooting is proposed as a solution to overcome essential limitations of the Gaussian Beam Shooting technique. The proposed algorithm is based on iterative frame decompositions of beam fields in situations where usual paraxial formulas fail to give accurate enough results, such as interactions with finite obstacle edges. Collimated beam fields are successively re-expanded on narrow and wide window frames, allowing for re-shooting and further propagation...

  16. Electron beam processing of polymers

    International Nuclear Information System (INIS)

    Silva, Leonardo G. Andrade e; Dias, Djalma B.; Calvo, Wilson A.P.; Miranda, Leila F. de

    2011-01-01

    The aim of this work is the use of electron beam produced by industrial electron accelerators to process polymers. There are several applications, such as, irradiation of wires and electric cables for automotive, aerospace, household appliance, naval and computing industries. The effect of different radiation doses in low density polyethylene (LDPE) was also studied. After irradiation and crosslinking it was thermally expanded forming LDPE foam. In addition, poly(N-vinyl-2-pyrrolidone) (PVP) hydrogels using electron beam processing were prepared. In all cases studied crosslinking percentages of the samples were determined. (author)

  17. Radioactive Ion Beams and Radiopharmaceuticals

    Science.gov (United States)

    Laxdal, R. E.; Morton, A. C.; Schaffer, P.

    2014-02-01

    Experiments performed at radioactive ion beam facilities shed new light on nuclear physics and nuclear structure, as well as nuclear astrophysics, materials science and medical science. The many existing facilities, as well as the new generation of facilities being built and those proposed for the future, are a testament to the high interest in this rapidly expanding field. The opportunities inherent in radioactive beam facilities have enabled the search for radioisotopes suitable for medical diagnosis or therapy. In this article, an overview of the production techniques and the current status of RIB facilities and proposals will be presented. In addition, accelerator-generated radiopharmaceuticals will be reviewed.

  18. Fragmentation in Carbon Therapy Beams

    CERN Document Server

    Charara, Y M

    2010-01-01

    The state of the art Monte Carlo code HETC-HEDS was used to simulate spallation products, secondary neutron, and secondary proton production in A-150 Tissue Equivalent Plastic phantoms to investigate fragmentation of carbon therapy beams. For a 356 MeV/Nucleon carbon ion beam, production of charged particles heavier than protons was 0.24 spallation products per incident carbon ion with atomic numbers ranging from 1 through 5 (hydrogen to boron). In addition, there were 4.73 neutrons and 2.95 protons produced per incident carbon ion. Furthermore, as the incident energy increases, the neutron production rate increases at a rate of 20% per 10 MeV/nucleon. Secondary protons were created at a rate between 2.62-2.87 per carbon ion, while spallation products were created at a rate between 0.20-0.24 per carbon ion.

  19. Molecular beams

    International Nuclear Information System (INIS)

    Ramsey, N.F.

    1985-01-01

    This book is a timeless and rather complete theoretical and experimental treatment of electric and magnetic resonance molecular-beam experiments for studying the radio frequency spectra of atoms and molecules. The theory of interactions of the nucleus with atomic and molecular fields is extensively presented. Measurements of atomic and nuclear magnetic moments, electric multipole moments, and atomic fine and hyperfine structure are detailed. Useful but somewhat outdated chapters on gas kinetics, molecular beam design, and experimental techniques are also included

  20. Beam transport

    International Nuclear Information System (INIS)

    1988-01-01

    Considerable experience has now been gained with the various beam transport lines, and a number of minor changes have been made to improve the ease of operation. These include: replacement of certain little-used slits by profile monitors (harps or scanners); relocation of steering magnets, closer to diagnostic harps or profile scanners; installation of a scanner inside the isocentric neutron therapy system; and conversion of a 2-doublet quadrupole telescope (on the neutron therapy beamline) to a 2-triplet telescope. The beam-swinger project has been delayed by very late delivery of the magnet iron to the manufacturer, but is now progressing smoothly. The K=600 spectrometer magnets have now been delivered and are being assembled for field mapping. The x,y-table with its associated mapping equipment is complete, together with the driver software. One of the experimental areas has been dedicated to the production of collimated neutron beams and has been equipped with a bending magnet and beam dump, together with steel collimators fixed at 4 degrees intervals from 0 degrees to 16 degrees. Changes to the target cooling and shielding system for isotope production have led to a request for much smaller beam spot sizes on target, and preparations have been made for rearrangement of the isotope beamline to permit installation of quadrupole triplets on the three beamlines after the switching magnet. A practical system of quadrupoles for matching beam properties to the spectrometer has been designed. 6 figs

  1. A pencil beam algorithm for helium ion beam therapy.

    Science.gov (United States)

    Fuchs, Hermann; Strobele, Julia; Schreiner, Thomas; Hirtl, Albert; Georg, Dietmar

    2012-11-01

    To develop a flexible pencil beam algorithm for helium ion beam therapy. Dose distributions were calculated using the newly developed pencil beam algorithm and validated using Monte Carlo (MC) methods. The algorithm was based on the established theory of fluence weighted elemental pencil beam (PB) kernels. Using a new real-time splitting approach, a minimization routine selects the optimal shape for each sub-beam. Dose depositions along the beam path were determined using a look-up table (LUT). Data for LUT generation were derived from MC simulations in water using GATE 6.1. For materials other than water, dose depositions were calculated by the algorithm using water-equivalent depth scaling. Lateral beam spreading caused by multiple scattering has been accounted for by implementing a non-local scattering formula developed by Gottschalk. A new nuclear correction was modelled using a Voigt function and implemented by a LUT approach. Validation simulations have been performed using a phantom filled with homogeneous materials or heterogeneous slabs of up to 3 cm. The beams were incident perpendicular to the phantoms surface with initial particle energies ranging from 50 to 250 MeV/A with a total number of 10(7) ions per beam. For comparison a special evaluation software was developed calculating the gamma indices for dose distributions. In homogeneous phantoms, maximum range deviations between PB and MC of less than 1.1% and differences in the width of the distal energy fall off of the Bragg-Peak from 80% to 20% of less than 0.1 mm were found. Heterogeneous phantoms using layered slabs satisfied a γ-index criterion of 2%/2mm of the local value except for some single voxels. For more complex phantoms using laterally arranged bone-air slabs, the γ-index criterion was exceeded in some areas giving a maximum γ-index of 1.75 and 4.9% of the voxels showed γ-index values larger than one. The calculation precision of the presented algorithm was considered to be sufficient

  2. Doppler-shifted neutral beam line shape and beam transmission

    Energy Technology Data Exchange (ETDEWEB)

    Kamperschroer, J.H.; Grisham, L.R.; Kokatnur, N.; Lagin, L.J.; Newman, R.A.; O`Connor, T.E.; Stevenson, T.N.; von Halle, A.

    1994-04-01

    Analysis of Doppler-shifted Balmer-{alpha} line emission from the TFTR neutral beam injection systems has revealed that the line shape is well approximated by the sum of two Gaussians, or, alternatively, by a Lorentzian. For the sum of two Gaussians, the broad portion of the distribution contains 40% of the beam power and has a divergence five times that of the narrow part. Assuming a narrow 1/e- divergence of 1.3{degrees} (based on fits to the beam shape on the calorimeter), the broad part has a divergence of 6.9{degrees}. The entire line shape is also well approximated by a Lorentzian with a half-maximum divergence of 0.9{degrees}. Up to now, fusion neutral beam modelers have assumed a single Gaussian velocity distribution, at the extraction plane, in each direction perpendicular to beam propagation. This predicts a beam transmission efficiency from the ion source to the calorimeter of 97%. Waterflow calorimetry data, however, yield a transmission efficiency of {approximately}75%, a value in rough agreement with predictions of the Gaussian or Lorentzian models presented here. The broad wing of the two Gaussian distribution also accurately predicts the loss in the neutralizer. An average angle of incidence for beam loss at the exit of the neutralizer is 2.2{degrees}, rather than the 4.95{degrees} subtended by the center of the ion source. This average angle of incidence, which is used in computing power densities on collimators, is shown to be a function of beam divergence.

  3. Doppler-shifted neutral beam line shape and beam transmission

    International Nuclear Information System (INIS)

    Kamperschroer, J.H.; Grisham, L.R.; Kokatnur, N.; Lagin, L.J.; Newman, R.A.; O'Connor, T.E.; Stevenson, T.N.; von Halle, A.

    1994-04-01

    Analysis of Doppler-shifted Balmer-α line emission from the TFTR neutral beam injection systems has revealed that the line shape is well approximated by the sum of two Gaussians, or, alternatively, by a Lorentzian. For the sum of two Gaussians, the broad portion of the distribution contains 40% of the beam power and has a divergence five times that of the narrow part. Assuming a narrow 1/e- divergence of 1.3 degrees (based on fits to the beam shape on the calorimeter), the broad part has a divergence of 6.9 degrees. The entire line shape is also well approximated by a Lorentzian with a half-maximum divergence of 0.9 degrees. Up to now, fusion neutral beam modelers have assumed a single Gaussian velocity distribution, at the extraction plane, in each direction perpendicular to beam propagation. This predicts a beam transmission efficiency from the ion source to the calorimeter of 97%. Waterflow calorimetry data, however, yield a transmission efficiency of ∼75%, a value in rough agreement with predictions of the Gaussian or Lorentzian models presented here. The broad wing of the two Gaussian distribution also accurately predicts the loss in the neutralizer. An average angle of incidence for beam loss at the exit of the neutralizer is 2.2 degrees, rather than the 4.95 degrees subtended by the center of the ion source. This average angle of incidence, which is used in computing power densities on collimators, is shown to be a function of beam divergence

  4. Winding light beams along elliptical helical trajectories

    Science.gov (United States)

    Wen, Yuanhui; Chen, Yujie; Zhang, Yanfeng; Chen, Hui; Yu, Siyuan

    2016-07-01

    Conventional caustic methods in real or Fourier space produced accelerating optical beams only with convex trajectories. We developed a superposition caustic method capable of winding light beams along nonconvex trajectories. We ascertain this method by constructing a one-dimensional (1D) accelerating beam moving along a sinusoidal trajectory, and subsequently extending to two-dimensional (2D) accelerating beams along arbitrarily elliptical helical trajectories. We experimentally implemented the method with a compact and robust integrated optics approach by fabricating micro-optical structures on quartz glass plates to perform the spatial phase and amplitude modulation to the incident light, generating beam trajectories highly consistent with prediction. The theoretical and implementation methods can in principle be extended to the construction of accelerating beams with a wide variety of nonconvex trajectories, thereby opening up a route of manipulating light beams for fundamental research and practical applications.

  5. Using prepulsing: a useful way for increasing absorption efficiency of high intensity laser beam

    International Nuclear Information System (INIS)

    Peng Huimin; Zhang Guoping; Sheng Jiatian

    1990-01-01

    Using prepulse to irradiate target for increasing absorption efficiency of high intensity incident laser beam is considered and some theoretical simulations have been done. 1-D non-LTE radiative hydrodynamic code is used to simulate the interactions of laser beam with matter. A gaussian laser prepulse of wavelength 1.06 μm, FWHM 600 ps and peak intensity 1.5 x 10 12 W/cm 2 was used to irradiate 20 μm thick Au plate target, after 3ns a main gaussian pulse with wavelength 1.06 μm, FWHM 600 ps and peak intensity 3.0 x 10 14 W/cm 2 irradiated the expanding Au plasma. The responces of laser-produced plasma conditions are shown. By comparing with without prepulsing, under the condition of same main incident laser pulse, the absorption efficiency is increased from 0.36 to 0.60 and the laser-x-ray conversion efficiency is increased from 0.16 to 0.25. The electron temperature of hot plasma is also higher than without prepulsing, and the x-ray spectrum which is emitted from laser-produced hot plasma is harder and more intense than without prepulsing. The responces of laser-produced plasma for Fe target with prepulsing are shown as well. The conclusion is that using prepulsing is a useful way for getting high absorption laser beam

  6. Experimental study and theoretical modeling of bidimensional beam fanning: application to DPCM

    Science.gov (United States)

    Mailhan, C.; Goetz, M.; Fressengeas, N.; Kugel, G.

    2001-10-01

    Features like efficiency and stability of the double phase conjugate mirror (DPCM) in BaTiO 3 obviously depend on the beam fanning (BF) experienced by each incident beam. We propose here a new approach to DPCM optimization which consists in studying the BF phenomenon for each interacting beam. This allows one to choose the best angular configuration of the incident beams in DPCM. The investigation is experimental, by recording the fanning patterns, and also theoretical, by interpreting numerically these patterns on the basis of the coupling gain maximization in the two-wave mixing theory. We focus on the influence of the incident beam width and incidence angle.

  7. Muon Beam Studies in the H4 beam line and the Gamma Irradiation Facility (GIF++)

    CERN Document Server

    Margraf, Rachel; CERN. Geneva. ATS Department

    2018-01-01

    In this note, we present detailed simulation results for the trajectory of a muon beam, traversing beam zones PPE-134 and PPE-154, produced by a 150 GeV positive hadron beam incident on collimators 9 & 10 in the H4 beam line when these collimators are placed off-beam axis to stop all hadrons and electrons. Using G4Beamline, a GEANT-4 based Monte-Carlo program, the trajectory of the muon beam has been studied for several field strengths of the GOLIATH magnet, as well as for different polarities. The position of the beam at the Gamma Irradiation Facility (GIF++), located downstream the PPE-144 area, is also presented. In addition, two configurations of the two XTDV’s present in the line (XTDV.022.520 and XTDV.022.610) have been studied, with the purpose to simulate the pion contamination of the beam both in PPE134 and GIF++.

  8. Particle reflection and TFTR neutral beam diagnostics

    International Nuclear Information System (INIS)

    Kamperschroer, J.H.; Grisham, L.R.; Kugel, H.W.; O'Connor, T.E.; Newman, R.A.; Stevenson, T.N.; von Halle, A.; Williams, M.D.

    1992-04-01

    Determination of two critical neutral beam parameters, power and divergence, are affected by the reflection of a fraction of the incident energy from the surface of the measuring calorimeter. On the TFTR Neutral Beam Test Stand, greater than 30% of the incident power directed at the target chamber calorimeter was unaccounted for. Most of this loss is believed due to reflection from the surface of the flat calorimeter, which was struck at a near grazing incidence (12 degrees). Beamline calorimeters, of a ''V''-shape design, while retaining the beam power, also suffer from reflection effects. Reflection, in this latter case, artificially peaks the power toward the apex of the ''V'', complicating the fitting technique, and increasing the power density on axis by 10 to 20%; an effect of import to future beamline designers. Agreement is found between measured and expected divergence values, even with 24% of the incident energy reflected

  9. Particle reflection and TFTR neutral beam diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Kamperschroer, J.H.; Grisham, L.R.; Kugel, H.W.; O`Connor, T.E.; Newman, R.A.; Stevenson, T.N.; von Halle, A.; Williams, M.D.

    1992-04-01

    Determination of two critical neutral beam parameters, power and divergence, are affected by the reflection of a fraction of the incident energy from the surface of the measuring calorimeter. On the TFTR Neutral Beam Test Stand, greater than 30% of the incident power directed at the target chamber calorimeter was unaccounted for. Most of this loss is believed due to reflection from the surface of the flat calorimeter, which was struck at a near grazing incidence (12{degrees}). Beamline calorimeters, of a ``V``-shape design, while retaining the beam power, also suffer from reflection effects. Reflection, in this latter case, artificially peaks the power toward the apex of the ``V``, complicating the fitting technique, and increasing the power density on axis by 10 to 20%; an effect of import to future beamline designers. Agreement is found between measured and expected divergence values, even with 24% of the incident energy reflected.

  10. Particle reflection and TFTR neutral beam diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Kamperschroer, J.H.; Grisham, L.R.; Kugel, H.W.; O' Connor, T.E.; Newman, R.A.; Stevenson, T.N.; von Halle, A.; Williams, M.D.

    1992-04-01

    Determination of two critical neutral beam parameters, power and divergence, are affected by the reflection of a fraction of the incident energy from the surface of the measuring calorimeter. On the TFTR Neutral Beam Test Stand, greater than 30% of the incident power directed at the target chamber calorimeter was unaccounted for. Most of this loss is believed due to reflection from the surface of the flat calorimeter, which was struck at a near grazing incidence (12{degrees}). Beamline calorimeters, of a V''-shape design, while retaining the beam power, also suffer from reflection effects. Reflection, in this latter case, artificially peaks the power toward the apex of the V'', complicating the fitting technique, and increasing the power density on axis by 10 to 20%; an effect of import to future beamline designers. Agreement is found between measured and expected divergence values, even with 24% of the incident energy reflected.

  11. Photon beam asymmetry Σ for η and η′ photoproduction from the proton

    Directory of Open Access Journals (Sweden)

    P. Collins

    2017-08-01

    Full Text Available Measurements of the linearly-polarized photon beam asymmetry Σ for photoproduction from the proton of η and η′ mesons are reported. A linearly-polarized tagged photon beam produced by coherent bremsstrahlung was incident on a cryogenic hydrogen target within the CEBAF Large Acceptance Spectrometer. Results are presented for the γp→ηp reaction for incident photon energies from 1.070 to 1.876 GeV, and from 1.516 to 1.836 GeV for the γp→η′p reaction. For γp→ηp, the data reported here considerably extend the range of measurements to higher energies, and are consistent with the few previously published measurements for this observable near threshold. For γp→η′p, the results obtained are consistent with the few previously published measurements for this observable near threshold, but also greatly expand the incident photon energy coverage for that reaction. Initial analysis of the data reported here with the Bonn–Gatchina model strengthens the evidence for four nucleon resonances – the N(18951/2−, N(19003/2+, N(21001/2+ and N(21203/2− resonances – which presently lack the “four-star” status in the current Particle Data Group compilation, providing examples of how these new measurements help refine models of the photoproduction process.

  12. Quantum beams

    International Nuclear Information System (INIS)

    Uesaka, Mitsuru

    2003-01-01

    Present state and future prospect are described on quantum beams for medical use. Efforts for compactness of linac for advanced cancer therapy have brought about the production of machines like Accuray's CyberKnife and TOMOTHERAPY (Tomo Therapy Inc.) where the acceleration frequency of X-band (9-11 GHz) is used. For cervical vein angiography by the X-band linac, a compact hard X-ray source is developed which is based on the (reverse) Compton scattering through laser-electron collision. More intense beam and laser are necessary at present. A compact machine generating the particle beam of 10 MeV-1 GeV (laser-plasma accelerator) for cancer therapy is also developed using the recent compression technique (chirped-pulse amplification) to generate laser of >10 TW. Tokyo University is studying for the electron beam with energy of GeV order, for the laser-based synchrotron X-ray, and for imaging by the short pulse ion beam. Development of advanced compact accelerators is globally attempted. In Japan, a virtual laboratory by National Institute of Radiological Sciences (NIRS), a working group of universities and research facilities through the Ministry of Education, Culture, Sports, Science and Technology, started in 2001 for practical manufacturing of the above-mentioned machines for cancer therapy and for angiography. Virtual Factory (Inc.), a business venture, is to be stood in future. (N.I.)

  13. Flow boiling in expanding microchannels

    CERN Document Server

    Alam, Tamanna

    2017-01-01

    This Brief presents an up to date summary of details of the flow boiling heat transfer, pressure drop and instability characteristics; two phase flow patterns of expanding microchannels. Results obtained from the different expanding microscale geometries are presented for comparison and addition to that, comparison with literatures is also performed. Finally, parametric studies are performed and presented in the brief. The findings from this study could help in understanding the complex microscale flow boiling behavior and aid in the design and implementation of reliable compact heat sinks for practical applications.

  14. Beam profile measurement on HITU transducers using a thermal intensity sensor technique

    International Nuclear Information System (INIS)

    Wilkens, V; Sonntag, S; Jenderka, K-V

    2011-01-01

    Thermal intensity sensors based on the transformation of the incident ultrasonic energy into heat inside a small cylindrical absorber have been developed at PTB in the past, in particular to determine the acoustic output of medical diagnostic ultrasound equipment. Currently, this sensor technique is being expanded to match the measurement challenges of high intensity therapeutic ultrasound (HITU) fields. At the high acoustic power levels as utilized in the clinical application of HITU transducers, beam characterization using hydrophones is critical due to the possible damage of the sensitive and expensive measurement devices. Therefore, the low-cost and robust thermal sensors developed offer a promising alternative for the determination of high intensity output beam profiles. A sensor prototype with a spatial resolution of 0.5 mm was applied to the beam characterization of an HITU transducer operated at several driving amplitude levels. Axial beam plots and lateral profiles at focus were acquired. The absolute continuous wave output power was, in addition, determined using a radiation force balance.

  15. BEAM-BEAM SIMULATIONS FOR DOUBLE-GAUSSIAN BEAMS.

    Energy Technology Data Exchange (ETDEWEB)

    MONTAG, C.; MALITSKY, N.; BEN-ZVI, I.; LITVINENKO, V.

    2005-05-16

    Electron cooling together with intra-beam scattering results in a transverse distribution that can best be described by a sum of two gaussians, one for the high-density core and one for the tails of the distribution. Simulation studies are being performed to understand the beam-beam interaction of these double-gaussian beams. Here we report the effect of low-frequency random tune modulations on diffusion in double-gaussian beams and compare the effects to those in beam-beam interactions with regular gaussian beams and identical tune shift parameters.

  16. BEAM-BEAM SIMULATIONS FOR DOUBLE-GAUSSIAN BEAMS

    International Nuclear Information System (INIS)

    MONTAG, C.; MALITSKY, N.; BEN-ZVI, I.; LITVINENKO, V.

    2005-01-01

    Electron cooling together with intra-beam scattering results in a transverse distribution that can best be described by a sum of two gaussians, one for the high-density core and one for the tails of the distribution. Simulation studies are being performed to understand the beam-beam interaction of these double-gaussian beams. Here we report the effect of loW--frequency random tune modulations on diffusion in double-gaussian beams and compare the effects to those in beam-beam interactions with regular gaussian beams and identical tune shift parameters

  17. Beam-Beam Simulations for Double-Gaussian Beams

    CERN Document Server

    Montag, Christoph; Litvinenko, Vladimir N; Malitsky, Nikolay

    2005-01-01

    Electron cooling together with intra-beam scattering results in a transverse distribution that can best be described by a sum of two Gaussians, one for the high-density core and one for the tails of the distribution. Simulation studies are being performed to understand the beam-beam interaction of these double-Gaussian beams. Here we report the effect of low-frequency random tune modulations on diffusion in double-Gaussian beams and compare the effects to those in beam-beam interactions with regular Gaussian beams and identical tuneshift parameters.

  18. Expanding nail or expanding femur? An adverse event with the expandable intramedullary nail.

    Science.gov (United States)

    Gangopadhyay, Soham; Riley, Nicholas D; Sivaji, Chellappan K

    2010-01-01

    The expandable intramedullary nail is self-locking and has the advantage of reducing operating time and exposure to ionizing radiation. The nail is recommended for simple diaphyseal fractures involving the middle third of long bones, where the nail can bypass the fracture site by at least 5 cm. We encountered a unique complication with the expandable nail in a simple transverse shaft fracture at the junction of the middle and distal third of the left femur in an otherwise healthy 57-year-old man. The fracture was reduced and a 12-mm expandable nail was inserted. Following full expansion, intraoperative radiographs were obtained prior to closure. After six postoperative weeks, it was noted that the nail expanded the femoral canal, converting a simple fracture to a distally progressing comminuted fracture with a butterfly fragment. A review of the intraoperative radiographs showed slight widening of the medullary canal at the level of the fracture. As the alignment was satisfactory and callus was present, no further surgical intervention was considered. The patient was advised not to bear weight and was provided with a locked knee brace in extension to wear for six weeks. Radiographs at 12 weeks demonstrated good progress of healing with adequate callus and the patient was permitted to bear weight as tolerated and commence knee flexion. The fracture united satisfactorily at four months. This adverse experience emphasizes that caution should be exercised when expanding the nail, with close observation of the medullary canal diameter during the later stages of expansion.

  19. Dependence of extinction cross-section on incident polarization state and particle orientation

    International Nuclear Information System (INIS)

    Yang Ping; Wendisch, Manfred; Bi Lei; Kattawar, George; Mishchenko, Michael; Hu, Yongxiang

    2011-01-01

    This note reports on the effects of the polarization state of an incident quasi-monochromatic parallel beam of radiation and the orientation of a hexagonal ice particle with respect to the incident direction on the extinction process. When the incident beam is aligned with the six-fold rotational symmetry axis, the extinction is independent of the polarization state of the incident light. For other orientations, the extinction cross-section for linearly polarized light can be either larger or smaller than its counterpart for an unpolarized incident beam. Therefore, the attenuation of a quasi-monochromatic radiation beam by an ice cloud depends on the polarization state of the beam if ice crystals within the cloud are not randomly oriented. Furthermore, a case study of the extinction of light by a quartz particle is also presented to illustrate the dependence of the extinction cross-section on the polarization state of the incident light.

  20. Expanding the eukaryotic genetic code

    Energy Technology Data Exchange (ETDEWEB)

    Chin, Jason W.; Cropp, T. Ashton; Anderson, J. Christopher; Schultz, Peter G.

    2017-02-28

    This invention provides compositions and methods for producing translational components that expand the number of genetically encoded amino acids in eukaryotic cells. The components include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, orthogonal pairs of tRNAs/synthetases and unnatural amino acids. Proteins and methods of producing proteins with unnatural amino acids in eukaryotic cells are also provided.

  1. Expanding the eukaryotic genetic code

    Science.gov (United States)

    Chin, Jason W.; Cropp, T. Ashton; Anderson, J. Christopher; Schultz, Peter G.

    2013-01-22

    This invention provides compositions and methods for producing translational components that expand the number of genetically encoded amino acids in eukaryotic cells. The components include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, orthogonal pairs of tRNAs/synthetases and unnatural amino acids. Proteins and methods of producing proteins with unnatural amino acids in eukaryotic cells are also provided.

  2. 77 FR 38747 - Reports by Air Carriers on Incidents Involving Animals During Air Transport

    Science.gov (United States)

    2012-06-29

    ...-2010-0211] RIN 2105-AE07 Reports by Air Carriers on Incidents Involving Animals During Air Transport... incidents involving animals during air transport, 14 CFR 234.13, to expand the reporting requirement to U.S... seats, to expand the definition of ``animal'' to include all cats and dogs transported by the carrier...

  3. Plane waves as tractor beams

    Science.gov (United States)

    Forgács, Péter; Lukács, Árpád; Romańczukiewicz, Tomasz

    2013-12-01

    It is shown that in a large class of systems, plane waves act as tractor beams: i.e., an incident plane wave can exert a pulling force on the scatterer. The underlying physical mechanism for the pulling force is due to the sufficiently strong scattering of the incoming wave into another mode carrying more momentum, in which case excess momentum is created behind the scatterer. This tractor beam or negative radiation pressure (NRP) effect, is found to be generic in systems with multiple scattering channels. In a birefringent medium, electromagnetic plane waves incident on a thin plate exert NRP of the same order of magnitude as optical radiation pressure, while in artificial dielectrics (metamaterials), the magnitude of NRP can even be macroscopic. In two dimensions, we study various scattering situations on vortices, and NRP is shown to occur by the scattering of heavy baryons into light leptons off cosmic strings, and by neutron scattering off vortices in the XY model.

  4. Expanding the Game Design Space

    DEFF Research Database (Denmark)

    Larsen, Lasse Juel; Majgaard, Gunver

    2016-01-01

    This article considers game design research in educational settings. Its focus is on how undergraduate students – particularly engineering students – learn computer game design. From observations conducted during our game design courses we have developed a model of expanded game design space....... It encapsulates the entire development process from the first ideas to the final game with emphasis on game design thinking. Our model of expanded game design space consists of four separate – yet interconnected – layers in the process of game development. The first layer addresses the importance of framing......, providing a clear game design assignment that involves the formulation of intended player experience and a description of game mechanics. The second layer focuses on game design thinking from six different aspects of game design chosen in relation to the framing of the game design assignment. The third...

  5. Helical screw expander evaluation project

    Science.gov (United States)

    McKay, R.

    1982-03-01

    A one MW helical rotary screw expander power system for electric power generation from geothermal brine was evaluated. The technology explored in the testing is simple, potentially very efficient, and ideally suited to wellhead installations in moderate to high enthalpy, liquid dominated field. A functional one MW geothermal electric power plant that featured a helical screw expander was produced and then tested with a demonstrated average performance of approximately 45% machine efficiency over a wide range of test conditions in noncondensing, operation on two-phase geothermal fluids. The Project also produced a computer equipped data system, an instrumentation and control van, and a 1000 kW variable load bank, all integrated into a test array designed for operation at a variety of remote test sites. Data are presented for the Utah testing and for the noncondensing phases of the testing in Mexico. Test time logged was 437 hours during the Utah tests and 1101 hours during the Mexico tests.

  6. Seal-less cryogenic expander

    International Nuclear Information System (INIS)

    Faria, L.E.; Christopher, E.H.

    1987-01-01

    In an expander for use in a split Stirling cycle refrigeration system of the type wherein a displacer moves with reciprocating motion inside an expander housing, and wherein a plunger force and a regenerator force are formed on the displacer, the plunger force cyclically varying and having a time of minimum and maximum plunger force amplitude, and the regenerator force cyclically varying and having a time of minimum and maximum regenerator force amplitude, the improvement is described comprising: (a) means for maintaining displacer forces, such that the maximum plunger force amplitude is substantially equal to the maximum regenerator force amplitude; and (b) means for adjusting a time difference, the time difference being the time between the time of maximum plunger force and the time of maximum regenerator force such that a measure of the cooling power of the refrigeration system is maximized

  7. RIKEN RI Beam Factory project

    International Nuclear Information System (INIS)

    Yano, Y.; Katayama, T.

    1996-01-01

    The RARF has a heavy-ion accelerator complex consisting of a K540-MeV ring cyclotron as a booster accelerator and two different types of injectors. The facility provides not only nuclear physicists but also researchers of atomic physics, nuclear chemistry, material science, radiobiology and others with various kinds of heavy-ion beams of an energy range of 10 MeV/nucleon to 100 MeV/nucleon. One of remarkable features of this facility is capability of supplying RI (radioactive isotope) beams with the world-highest level of intensities. In these several years the RI beam has opened up a quite new and fascinating heavy-ion science. In order to further promote this new science, we propose open-quote open-quote RIKEN RI Beam Factory close-quote close-quote as a future project of the RARF: The existing facility will be expanded into the open-quote open-quote Factory close-quote close-quote where high-intensity RI beams of the whole mass range will become available in a wide energy range up to several hundred MeV/nucleon. The concept of this new proposal as well as currently-running upgrade programs relevant to the project will be presented. copyright 1996 American Institute of Physics

  8. Beam transport

    International Nuclear Information System (INIS)

    1988-01-01

    The beam diagnostic components for both the transfer and the high-energy beamlines perform well except for some of the scanners whose noise pick-up has become a problem, especially at low beam intensities. This noise pick-up is primarily due to deterioration of the bearings in the scanner. At some locations in the high-energy beamlines, scanners were replaced by harps as the scanners proved to be practically useless for the low-intensity beams required in the experimental areas. The slits in the low-energy beamline, which are not water-cooled, have to be repaired at regular intervals because of vacuum leaks. Overheating causes the ceramic feedthroughs to deteriorate resulting in the vacuum leaks. Water-cooled slits have been ordered to replace the existing slits which will later be used in the beamlines associated with the second injector cyclotron SPC2. The current-measurement system will be slightly modified and should then be much more reliable. 3 figs

  9. Closed form formula for Mie scattering of nonparaxial analogues of Gaussian beams.

    Science.gov (United States)

    Moore, Nicole J; Alonso, Miguel A

    2008-04-14

    A closed form formula is found for the Mie scattering coefficients of incident complex focus beams (which are a nonparaxial generalization of Gaussian beams) with any numerical aperture. This formula takes the compact form of multipoles evaluated at a single complex point. Included are the cases of incident scalar fields as well as electromagnetic fields with many polarizations, such as linear, circular, azimuthal and radial. Examples of incident radially and azimuthally polarized beams are presented.

  10. Accelerator business in Japan expanding

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    Accelerators have become to be used increasingly in Japan in such fields as medicine, physics research and industry. This has caused stiff competition for market share by the manufacturers of accelerators. Electron beam accelerators for industrial use provide an indispensable means for adding values to products, for example, electric cables with incombustible insulators. Linear accelerators for the nondestructive inspection of nuclear components have been widely installed at equipment manufacturing plants. Active efforts have been exerted to develop small synchrotron radiation accelerators for next generation electronic industry. Cyclotrons for producing short life radioisotopes for medical diagnosis and electron beam accelerators for radiation therapy are also used routinely. The suppliers of accelerators include the companies manufacturing heavy electric machinery, heavy machinery and the engineering division of steelmakers. Accelerator physics is being formed, but universities do not yet offer the course regarding accelerators. Accelerator use in Japan and the trend of accelerator manufacturers are reported. (K.I.)

  11. Short Rayleigh length free electron laser simulations in expanding coordinates / Proceedings of the 2004 FEL Conference

    OpenAIRE

    Armstead, R.L.; Colson, W.B.; Blau, J.

    2004-01-01

    For compact short-Rayleigh length free electron lasers (FELs), the area of the optical beam can be thousands of times greater at the mirrors than at the beam waist. A fixed numerical grid of sufficient resolution to represent the narrow mode at the waist and the broad mode at the mirrors would be prohibitively large. To accommodate this extreme change of scale with no loss of information, we employ a coordinate system that expands with the diffracting optical mode. The...

  12. Laser beam shaping design based on micromirror array

    Science.gov (United States)

    Fang, Han; Su, Bida; Liu, Jiaguo; Fan, Xiaoli; Jing, Wang

    2017-10-01

    In the practical application of the laser, it is necessary to use the laser beam shaping technology to shape the output beam of laser device to the uniform light intensity distribution. The shaping divergent optical system of compound eye integrator way is composed of beam expanding mirror group and lens array. Its working principle is to expand the output laser to a certain size of caliber, and then divide the beam with lens array into multiple sub beam, where the lens unit of lens array can control the divergence angle of sub beam through the design of focal length, with mutual superposition of the sub beam in far field, to make up for the nonuniformity of beam, so that the radiant exitance on the radiated surface may become uniform. In this paper, we use a reflective microlens array to realize the laser beam shaping. By through of the practical optical path model established, the ray tracing is carried out and the simulation results for single-mode Gaussian beam with noise circumstance is provided. The analysis results show that the laser beam shaping under different inputs can be effectively realized by use of microlens array. All the energy is within the signal window, with a high energy efficiency of more than 90%; The measured surface has a better uniformity, and the uniformity is better than 99.5% at 150m.

  13. Beam divergence scaling in neutral beam injectors

    International Nuclear Information System (INIS)

    Holmes, A.J.T.

    1976-01-01

    One of the main considerations in the design of neutral beam injectors is to monimize the divergence of the primary ion beam and hence maximize the beam transport and minimize the input of thermal gas. Experimental measurements of the divergence of a cylindrical ion beam are presented and these measurements are used to analyze the major components of ion beam divergence, namely: space charge expansion, gas-ion scattering, emittance and optical aberrations. The implication of these divergence components in the design of a neutral beam injector system is discussed and a method of maximizing the beam current is described for a given area of source plasma

  14. Beam screens for the LHC beam pipes

    CERN Multimedia

    Patrice Loïez

    1997-01-01

    Cross-section of LHC prototype beam pipes showing the beam screens. Slits in the screens allow residual gas molecules to be pumped out and become frozen to the walls of the ultra-cold beam pipe. Beam screens like these have been designed to line the beam pipes, absorbing radiation before it can hit the magnets and warm them up, an effect that would greatly reduce the magnetic field and cause serious damage.

  15. Expanding Business With Effective Networking

    OpenAIRE

    Lehto, Tanja

    2012-01-01

    The aim of the thesis process was to investigate networking, personal selling and Russian markets in order to create a clear view of what is vital for effective networking in Russia. The objective of the study was to observe the case company´s readiness for expanding operations to Russia as well as analyzing the company´s existing values and how they could be developed further. Additionally the purpose of the thesis was to give recommendations of the factors needed to be developed and suggest...

  16. Beam geometry selection using sequential beam addition.

    Science.gov (United States)

    Popple, Richard A; Brezovich, Ivan A; Fiveash, John B

    2014-05-01

    The selection of optimal beam geometry has been of interest since the inception of conformal radiotherapy. The authors report on sequential beam addition, a simple beam geometry selection method, for intensity modulated radiation therapy. The sequential beam addition algorithm (SBA) requires definition of an objective function (score) and a set of candidate beam geometries (pool). In the first iteration, the optimal score is determined for each beam in the pool and the beam with the best score selected. In the next iteration, the optimal score is calculated for each beam remaining in the pool combined with the beam selected in the first iteration, and the best scoring beam is selected. The process is repeated until the desired number of beams is reached. The authors selected three treatment sites, breast, lung, and brain, and determined beam arrangements for up to 11 beams from a pool comprised of 25 equiangular transverse beams. For the brain, arrangements were additionally selected from a pool of 22 noncoplanar beams. Scores were determined for geometries comprised equiangular transverse beams (EQA), as well as two tangential beams for the breast case. In all cases, SBA resulted in scores superior to EQA. The breast case had the strongest dependence on beam geometry, for which only the 7-beam EQA geometry had a score better than the two tangential beams, whereas all SBA geometries with more than two beams were superior. In the lung case, EQA and SBA scores monotonically improved with increasing number of beams; however, SBA required fewer beams to achieve scores equivalent to EQA. For the brain case, SBA with a coplanar pool was equivalent to EQA, while the noncoplanar pool resulted in slightly better scores; however, the dose-volume histograms demonstrated that the differences were not clinically significant. For situations in which beam geometry has a significant effect on the objective function, SBA can identify arrangements equivalent to equiangular

  17. Beam geometry selection using sequential beam addition

    Energy Technology Data Exchange (ETDEWEB)

    Popple, Richard A., E-mail: rpopple@uabmc.edu; Brezovich, Ivan A.; Fiveash, John B. [Department of Radiation Oncology, The University of Alabama at Birmingham, 1720 2nd Avenue South, Birmingham, Alabama 35294 (United States)

    2014-05-15

    Purpose: The selection of optimal beam geometry has been of interest since the inception of conformal radiotherapy. The authors report on sequential beam addition, a simple beam geometry selection method, for intensity modulated radiation therapy. Methods: The sequential beam addition algorithm (SBA) requires definition of an objective function (score) and a set of candidate beam geometries (pool). In the first iteration, the optimal score is determined for each beam in the pool and the beam with the best score selected. In the next iteration, the optimal score is calculated for each beam remaining in the pool combined with the beam selected in the first iteration, and the best scoring beam is selected. The process is repeated until the desired number of beams is reached. The authors selected three treatment sites, breast, lung, and brain, and determined beam arrangements for up to 11 beams from a pool comprised of 25 equiangular transverse beams. For the brain, arrangements were additionally selected from a pool of 22 noncoplanar beams. Scores were determined for geometries comprised equiangular transverse beams (EQA), as well as two tangential beams for the breast case. Results: In all cases, SBA resulted in scores superior to EQA. The breast case had the strongest dependence on beam geometry, for which only the 7-beam EQA geometry had a score better than the two tangential beams, whereas all SBA geometries with more than two beams were superior. In the lung case, EQA and SBA scores monotonically improved with increasing number of beams; however, SBA required fewer beams to achieve scores equivalent to EQA. For the brain case, SBA with a coplanar pool was equivalent to EQA, while the noncoplanar pool resulted in slightly better scores; however, the dose-volume histograms demonstrated that the differences were not clinically significant. Conclusions: For situations in which beam geometry has a significant effect on the objective function, SBA can identify

  18. Stable beams

    CERN Multimedia

    2015-01-01

    Stable beams: two simple words that carry so much meaning at CERN. When LHC page one switched from "squeeze" to "stable beams" at 10.40 a.m. on Wednesday, 3 June, it triggered scenes of jubilation in control rooms around the CERN sites, as the LHC experiments started to record physics data for the first time in 27 months. This is what CERN is here for, and it’s great to be back in business after such a long period of preparation for the next stage in the LHC adventure.   I’ve said it before, but I’ll say it again. This was a great achievement, and testimony to the hard and dedicated work of so many people in the global CERN community. I could start to list the teams that have contributed, but that would be a mistake. Instead, I’d simply like to say that an achievement as impressive as running the LHC – a machine of superlatives in every respect – takes the combined effort and enthusiasm of everyone ...

  19. Optics with an Atom Laser Beam

    International Nuclear Information System (INIS)

    Bloch, Immanuel; Koehl, Michael; Greiner, Markus; Haensch, Theodor W.; Esslinger, Tilman

    2001-01-01

    We report on the atom optical manipulation of an atom laser beam. Reflection, focusing, and its storage in a resonator are demonstrated. Precise and versatile mechanical control over an atom laser beam propagating in an inhomogeneous magnetic field is achieved by optically inducing spin flips between atomic ground states with different magnetic moment. The magnetic force acting on the atoms can thereby be effectively switched on and off. The surface of the atom optical element is determined by the resonance condition for the spin flip in the inhomogeneous magnetic field. More than 98% of the incident atom laser beam is reflected specularly

  20. Simulation and Measurements of Beam Losses on LHC Collimators During Beam Abort Failures

    CERN Document Server

    Lari, L; Bruce, R; Goddard, B; Redaelli, S; Salvachua, B; Valentino, G; Faus-Golfe, A

    2013-01-01

    One of the main purposes of tracking simulations for collimation studies is to produce loss maps along the LHC ring, in order to identify the level of local beam losses during nominal and abnormal operation scenarios. The SixTrack program is the standard tracking tool used at CERN to perform these studies. Recently, it was expanded in order to evaluate the proton load on different collimators in case of fast beam failures. Simulations are compared with beam measurements at 4 TeV. Combined failures are assumed which provide worst-case scenarios of the load on tungsten tertiary collimators.

  1. Carbon sputtering yield measurements at grazing incidence

    International Nuclear Information System (INIS)

    Kolasinski, Robert D.; Polk, James E.; Goebel, Dan; Johnson, Lee K.

    2008-01-01

    In this investigation, carbon sputtering yields were measured experimentally at varying angles of incidence under Xe + bombardment. The measurements were obtained by etching a coated quartz crystal microbalance (QCM) with a low energy ion beam. The material properties of the carbon targets were characterized with a scanning electron microscope (SEM) and Raman spectroscopy. C sputtering yields measured under Ar + and Xe + bombardment at normal incidence displayed satisfactory agreement with previously published data over an energy range of 200 eV-1 keV. For Xe + ions, the dependence of the yields on angle of incidence θ was determined for 0 o ≤ θ ≤ 80 deg. Over this range, an increase in C sputtering yield by a factor of 4.8 was observed, with the peak in yield occurring at 70 o . This is a much higher variation compared to Xe + → Mo yields under similar conditions, a difference that may be attributed to higher scattering of the incident particles transverse to the beam direction than in the case of Xe + → C. In addition, the variation of the yields with θ was not strongly energy dependent. Trapping of Xe in the surface was observed, in contrast to observations using the QCM technique with metallic target materials. Finally, target surface roughness was characterized using atomic force microscope measurements to distinguish between the effects of local and overall angle of incidence of the target

  2. Confocal retinal imaging using scanning laser opthalmoscopy with annular beams

    NARCIS (Netherlands)

    Vohnsen, Brian; Lochocki, Benjamin; Vela-Garcia, Carmen; Rativa, Diego

    2012-01-01

    The human retina has been imaged in-vivo using scanning laser ophthalmoscopy employing annular incident beams adapted for resolution optimization. The pros and cons of the approach are discussed and the importance of coherence is explored.

  3. Applications of power beaming from space-based nuclear power stations. [Laser beaming to airplanes; microwave beaming to ground

    Energy Technology Data Exchange (ETDEWEB)

    Powell, J.R.; Botts, T.E.; Hertzberg, A.

    1981-01-01

    Power beaming from space-based reactor systems is examined using an advanced compact, lightweight Rotating Bed Reactor (RBR). Closed Brayton power conversion efficiencies in the range of 30 to 40% can be achieved with turbines, with reactor exit temperatures on the order of 2000/sup 0/K and a liquid drop radiator to reject heat at temperatures of approx. 500/sup 0/K. Higher RBR coolant temperatures (up to approx. 3000/sup 0/K) are possible, but gains in power conversion efficiency are minimal, due to lower expander efficiency (e.g., a MHD generator). Two power beaming applications are examined - laser beaming to airplanes and microwave beaming to fixed ground receivers. Use of the RBR greatly reduces system weight and cost, as compared to solar power sources. Payback times are a few years at present prices for power and airplane fuel.

  4. Strategies for mitigating the ionization-induced beam head erosion problem in an electron-beam-driven plasma wakefield accelerator

    Directory of Open Access Journals (Sweden)

    W. An

    2013-10-01

    Full Text Available Strategies for mitigating ionization-induced beam head erosion in an electron-beam-driven plasma wakefield accelerator (PWFA are explored when the plasma and the wake are both formed by the transverse electric field of the beam itself. Beam head erosion can occur in a preformed plasma because of a lack of focusing force from the wake at the rising edge (head of the beam due to the finite inertia of the electrons. When the plasma is produced by field ionization from the space charge field of the beam, the head erosion is significantly exacerbated due to the gradual recession (in the beam frame of the 100% ionization contour. Beam particles in front of the ionization front cannot be focused (guided causing them to expand as in vacuum. When they expand, the location of the ionization front recedes such that even more beam particles are completely unguided. Eventually this process terminates the wake formation prematurely, i.e., well before the beam is depleted of its energy. Ionization-induced head erosion can be mitigated by controlling the beam parameters (emittance, charge, and energy and/or the plasma conditions. In this paper we explore how the latter can be optimized so as to extend the beam propagation distance and thereby increase the energy gain. In particular we show that, by using a combination of the alkali atoms of the lowest practical ionization potential (Cs for plasma formation and a precursor laser pulse to generate a narrow plasma filament in front of the beam, the head erosion rate can be dramatically reduced. Simulation results show that in the upcoming “two-bunch PWFA experiments” on the FACET facility at SLAC national accelerator laboratory the energy gain of the trailing beam can be up to 10 times larger for the given parameters when employing these techniques. Comparison of the effect of beam head erosion in preformed and ionization produced plasmas is also presented.

  5. Hot ion buildup by low current neutron beam injection in LITE

    International Nuclear Information System (INIS)

    Tomlinson, R.G.; Ard, W.B.; Fader, W.J.; Polk, D.H.; Mensing, A.E.; Stufflebeam, J.H.

    1976-01-01

    The laser produced target plasma confined in the LITE minimum-B mirror magnetic field is shown along with a drawing of the confinement field line configuration. The plasma is generated by two beam, 1.06 micron, Nd-glass laser irradiation of LiH particles approximately 100 microns in diameter producing a plasma of approximately 10 16 hydrogen and lithium ions which expands in and is captured by the ''baseball'' confinement field. The plasma luminosity displays a plasma configuration which corresponds to the magnetic field geometry and indicates a plasma volume of approximately 400 cm 3 . Probe and microwave measurements confirm the plasma distribution indicated by the luminosity photographs. Charge collector probes located at a series of positions over a 120 0 arc in the mirror fan permit simultaneous observations of the plasma decay along field lines which pass through the mid-plane at different radial distances from the magnetic field axis. Plasma flux is observed with these probes to field lines 6 cm from the axis. Microwave measurements have been made with a strongly focused, 75 GHz (lambda = 4 mm) beam passing through the mid-plane, orthogonal to the mirror axis. Cut-off of the microwave beam transmission early in the confined plasma time history indicates that the radial dimension of the high density plasma region exceeds 2 cm. Measurement of the line density via interferometric measurements of the phase shift of the transmitted beam when the density has fallen below cut-off indicates an ''effective'' diameter of approximately 5 cm and an axial extent of approximately 20 cm. Thus, the plasma presents approximately 100 cm 2 target area to an incident neutral beam and occupies approximately 400 cm 3 volume

  6. MCFRS Incidents by Station

    Data.gov (United States)

    Montgomery County of Maryland — This dataset contains the monthly summary data indicating incident occurred in each fire station response area. The summary data is the incident count broken down by...

  7. Police Incident Reports Written

    Data.gov (United States)

    Town of Chapel Hill, North Carolina — This table contains incident reports filed with the Chapel Hill Police Department. Multiple incidents may have been reported at the same time. The most serious...

  8. Beam-beam effects in the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Shiltsev, V.; Alexahin, Y.; Lebedev, V.; Lebrun, P.; Moore, R.S.; Sen, T.; Tollestrup, A.; Valishev, A.; Zhang, X.L.; /Fermilab

    2005-01-01

    The Tevatron in Collider Run II (2001-present) is operating with 6 times more bunches, many times higher beam intensities and luminosities than in Run I (1992-1995). Electromagnetic long-range and head-on interactions of high intensity proton and antiproton beams have been significant sources of beam loss and lifetime limitations. We present observations of the beam-beam phenomena in the Tevatron and results of relevant beam studies. We analyze the data and various methods employed in operations, predict the performance for planned luminosity upgrades, and discuss ways to improve it.

  9. Crystalline beams

    International Nuclear Information System (INIS)

    Schiffer, J.P.

    1989-01-01

    Ions in a storage ring are confined to a mean orbit by focusing elements. To a first approximation these may be described by a constant harmonic restoring force: F = -Kr. If the particles in the frame moving along with the beam have small random thermal energies, then they will occupy a cylindrical volume around the mean orbit and the focusing force will be balanced by that from the mutual repulsion of the particles. Inside the cylinder only residual two-particle interactions will play a significant role and some form of ordering might be expected to take place. The results of some of the first MD calculations showed a surprising result: not only were the particles arranged in the form of a tube, but they formed well-defined layers: concentric shells, with the particles in each shell arranged in a hexagonal lattice that is characteristic of two-dimensional Coulomb systems. This paper discusses the condense layer structure

  10. Leak detection with expandable coatings

    Science.gov (United States)

    1971-01-01

    Developed and evaluated is a system for leak detection that can be easily applied over separable connectors and that expands into a bubble or balloon if a leak is present. This objective is accomplished by using thin films of Parafilm tape wrapped over connectors, which are then overcoated with a special formulation. The low yield strength and the high elongation of the envelope permit bubble formation if leakage occurs. This system is appropriate for welds and other hardware besides separable connectors. The practical limit of this system appears to be for leaks exceeding 0.000001 cc/sec. If this envelope is used to trap gases for mass spectrometer inspection, leaks in the range of ten to the minus 8th power cc/sec. may be detectable.

  11. OCT Expanded Clinical Data Analysis

    Science.gov (United States)

    Van Baalen, Mary; Tafreshi, Ali; Patel, Nimesh; Young, Millennia; Mason, Sara; Otto, Christian; Samuels, Brian; Koslovsky, Matthew; Schaefer, Caroline; Taiym, Wafa; hide

    2017-01-01

    Vision changes identified in long duration space fliers has led to a more comprehensive clinical monitoring protocol. Optical Coherence Tomography (OCT) was recently implemented on board the International Space Station in 2013. NASA is collaborating with Heidelberg Engineering to expand our current OCT data analysis capability by implementing a volumetric approach. Volumetric maps will be created by combining the circle scan, the disc block scan, and the radial scan. This assessment may provide additional information about the optic nerve and further characterize changes related microgravity exposure. We will discuss challenges with collection and analysis of OCT data, present the results of this reanalysis and outline the potential benefits and limitations of the additional data.

  12. Instability of expanding bacterial droplets.

    Science.gov (United States)

    Sokolov, Andrey; Rubio, Leonardo Dominguez; Brady, John F; Aranson, Igor S

    2018-04-03

    Suspensions of motile bacteria or synthetic microswimmers, termed active matter, manifest a remarkable propensity for self-organization, and formation of large-scale coherent structures. Most active matter research deals with almost homogeneous in space systems and little is known about the dynamics of strongly heterogeneous active matter. Here we report on experimental and theoretical studies on the expansion of highly concentrated bacterial droplets into an ambient bacteria-free fluid. The droplet is formed beneath a rapidly rotating solid macroscopic particle inserted in the suspension. We observe vigorous instability of the droplet reminiscent of a violent explosion. The phenomenon is explained in terms of continuum first-principle theory based on the swim pressure concept. Our findings provide insights into the dynamics of active matter with strong density gradients and significantly expand the scope of experimental and analytic tools for control and manipulation of active systems.

  13. Preventive Ethics Through Expanding Education.

    Science.gov (United States)

    Ho, Anita; MacDonald, Lisa Mei-Hwa; Unger, David

    2016-03-01

    Healthcare institutions have been making increasing efforts to standardize consultation methodology and to accredit both bioethics training programs and the consultants accordingly. The focus has traditionally been on the ethics consultation as the relevant unit of ethics intervention. Outcome measures are studied in relation to consultations, and the hidden assumption is that consultations are the preferred or best way to address day-to-day ethical dilemmas. Reflecting on the data from an internal quality improvement survey and the literature, we argue that having general ethics education as a key function of ethics services may be more important in meeting the contemporaneous needs of acute care settings. An expanded and varied ethics education, with attention to the time constraints of healthcare workers' schedules, was a key recommendation brought forward by survey respondents. Promoting ethical reflection and creating a culture of ethics may serve to prevent ethical dilemmas or mitigate their effects.

  14. SHEAR ACCELERATION IN EXPANDING FLOWS

    Energy Technology Data Exchange (ETDEWEB)

    Rieger, F. M. [ZAH, Institut für Theoretische Astrophysik, Universität Heidelberg, Philosophenweg 12, D-69120 Heidelberg (Germany); Duffy, P., E-mail: frank.rieger@mpi-hd.mpg.de, E-mail: peter.duffy@ucd.ie [University College Dublin, Belfield, Dublin 4 (Ireland)

    2016-12-10

    Shear flows are naturally expected to occur in astrophysical environments and potential sites of continuous non-thermal Fermi-type particle acceleration. Here we investigate the efficiency of expanding relativistic outflows to facilitate the acceleration of energetic charged particles to higher energies. To this end, the gradual shear acceleration coefficient is derived based on an analytical treatment. The results are applied to the context of the relativistic jets from active galactic nuclei. The inferred acceleration timescale is investigated for a variety of conical flow profiles (i.e., power law, Gaussian, Fermi–Dirac) and compared to the relevant radiative and non-radiative loss timescales. The results exemplify that relativistic shear flows are capable of boosting cosmic-rays to extreme energies. Efficient electron acceleration, on the other hand, requires weak magnetic fields and may thus be accompanied by a delayed onset of particle energization and affect the overall jet appearance (e.g., core, ridge line, and limb-brightening).

  15. Incident Information Management Tool

    CERN Document Server

    Pejovic, Vladimir

    2015-01-01

    Flaws of\tcurrent incident information management at CMS and CERN\tare discussed. A new data\tmodel for future incident database is\tproposed and briefly described. Recently developed draft version of GIS-­‐based tool for incident tracking is presented.

  16. Optical design of multi-multiple expander structure of laser gas analysis and measurement device

    Science.gov (United States)

    Fu, Xiang; Wei, Biao

    2018-03-01

    The installation and debugging of optical circuit structure in the application of carbon monoxide distributed laser gas analysis and measurement, there are difficult key technical problems. Based on the three-component expansion theory, multi-multiple expander structure with expansion ratio of 4, 5, 6 and 7 is adopted in the absorption chamber to enhance the adaptability of the installation environment of the gas analysis and measurement device. According to the basic theory of aberration, the optimal design of multi-multiple beam expander structure is carried out. By using image quality evaluation method, the difference of image quality under different magnifications is analyzed. The results show that the optical quality of the optical system with the expanded beam structure is the best when the expansion ratio is 5-7.

  17. Improvements in or relating to electron beam deflection arrangements

    International Nuclear Information System (INIS)

    Bull, E.W.

    1979-01-01

    This relates to the deflection of ribbon-like electron beams in X-ray tubes particularly in radiographic equipment. The X-ray tubes includes a source of a ribbon-shaped beam of electrons relatively narrow in a direction orthogonal to the direction of the beam and relatively wide in a second orthogonal direction. An elongated target projects X-rays about a chosen direction in response to the incident beam. There is a means (toroidal former, deflection coils or plates) for deflecting the electron beam to scan the region of incidence along the target and correction means for changing the shape of the electron beam depending on the deflection so that the region of incidence of the deflected beam remains a linear region substantially parallel to the region of incidence of the undeflected beam. The apparatus for this, and variations, are described. A medical radiography unit (computerise axial tomography) including the X-ray tube described is also detailed. (U.K.)

  18. Beam halo in high-intensity beams

    International Nuclear Information System (INIS)

    Wangler, T.P.

    1993-01-01

    In space-charge dominated beams the nonlinear space-charge forces produce a filamentation pattern, which in projection to the 2-D phase spaces results in a 2-component beam consisting of an inner core and a diffuse outer halo. The beam-halo is of concern for a next generation of cw, high-power proton linacs that could be applied to intense neutron generators for nuclear materials processing. The author describes what has been learned about beam halo and the evolution of space-charge dominated beams using numerical simulations of initial laminar beams in uniform linear focusing channels. Initial results are presented from a study of beam entropy for an intense space-charge dominated beam

  19. Incident spectrum determination for time-of-flight neutron powder diffraction data analysis

    International Nuclear Information System (INIS)

    Hodges, J. P.

    1998-01-01

    Accurate characterization of the incident neutron spectrum is an important requirement for precise Rietveld analysis of time-of-flight powder neutron diffraction data. Without an accurate incident spectrum the calculated model for the measured relative intensities of individual Bragg reflections will possess systematic errors. We describe a method for obtaining an accurate numerical incident spectrum using data from a transmitted beam monitor

  20. Laser Incident Lessons Learned and Action List

    Energy Technology Data Exchange (ETDEWEB)

    Yarotski, Dmitry Anatolievitch [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-02-29

    On Thursday November 19, 2015, LANL postdoc received an eye injury from a reflected, nonvisible laser beam (Class 4, pulsed, wavelength 800 nanometer). The setup is configured to split the laser output into two work areas in which qualified operators conduct research experiments. During this incident, the laser output beam was being projected to both experimental work areas, although only one experimental area was actively being used. The second laser beam directed to the second work area was blocked by an inappropriate device (Plexiglas, reflective, non-normal incidence) that reflected substantial portion of the beam toward the first setup. In preparation for the measurements, worker stepped on the stepstool and decided to remove the laser goggles to better see the micrometer readings which were difficult to see due to insufficient lighting. Immediately, he noticed a flash of light in his eye. The operator quickly replaced the laser eye-wear and then, using an infrared viewer, located a stray laser beam being reflected from the plexiglas beam block. The operator did not think he had sustained any injury and continued working. Later that day, however, he noticed a blurry spot in the vision of his left eye. He notified his supervisor on Friday morning, November 20, 2015, and was taken by CINT management to Sandia National Laboratories (SNL) medical facility for evaluation. SNL Medical did not find any abnormalities, but referred the operator to a local ophthalmologist for further evaluation. Further evaluations by the ophthalmologist on November 21 and November 23 identified a small spot of inflammation near the fovea on the retina in his left eye. The ophthalmologist stated that this spot would most likely heal on its own and that the blurry spot on the operator's vision would go away. A follow-up visit was scheduled. The employee was released back to work without restrictions.

  1. Semi-analytical solution to arbitrarily shaped beam scattering

    Science.gov (United States)

    Wang, Wenjie; Zhang, Huayong; Sun, Yufa

    2017-07-01

    Based on the field expansions in terms of appropriate spherical vector wave functions and the method of moments scheme, an exact semi-analytical solution to the scattering of an arbitrarily shaped beam is given. For incidence of a Gaussian beam, zero-order Bessel beam and Hertzian electric dipole radiation, numerical results of the normalized differential scattering cross section are presented to a spheroid and a circular cylinder of finite length, and the scattering properties are analyzed concisely.

  2. Molecular-beam scattering

    International Nuclear Information System (INIS)

    Vernon, M.F.

    1983-07-01

    The molecular-beam technique has been used in three different experimental arrangements to study a wide range of inter-atomic and molecular forces. Chapter 1 reports results of a low-energy (0.2 kcal/mole) elastic-scattering study of the He-Ar pair potential. The purpose of the study was to accurately characterize the shape of the potential in the well region, by scattering slow He atoms produced by expanding a mixture of He in N 2 from a cooled nozzle. Chapter 2 contains measurements of the vibrational predissociation spectra and product translational energy for clusters of water, benzene, and ammonia. The experiments show that most of the product energy remains in the internal molecular motions. Chapter 3 presents measurements of the reaction Na + HCl → NaCl + H at collision energies of 5.38 and 19.4 kcal/mole. This is the first study to resolve both scattering angle and velocity for the reaction of a short lived (16 nsec) electronic excited state. Descriptions are given of computer programs written to analyze molecular-beam expansions to extract information characterizing their velocity distributions, and to calculate accurate laboratory elastic-scattering differential cross sections accounting for the finite apparatus resolution. Experimental results which attempted to determine the efficiency of optically pumping the Li(2 2 P/sub 3/2/) and Na(3 2 P/sub 3/2/) excited states are given. A simple three-level model for predicting the steady-state fraction of atoms in the excited state is included

  3. Reflection and transmission of normally incident full-vector X waves on planar interfaces

    KAUST Repository

    Salem, Mohamed

    2011-12-23

    The reflection and transmission of full-vector X waves normally incident on planar half-spaces and slabs are studied. For this purpose, X waves are expanded in terms of weighted vector Bessel beams; this new decomposition and reconstruction method offers a more lucid and intuitive interpretation of the physical phenomena observed upon the reflection or transmission of X waves when compared to the conventional plane-wave decomposition technique. Using the Bessel beam expansion approach, we have characterized changes in the field shape and the intensity distribution of the transmitted and reflected full-vector X waves. We have also identified a novel longitudinal shift, which is observed when a full-vector X wave is transmitted through a dielectric slab under frustrated total reflection condition. The results of our studies presented here are valuable in understanding the behavior of full-vector X waves when they are utilized in practical applications in electromagnetics, optics, and photonics, such as trap and tweezer setups, optical lithography, and immaterial probing. © 2011 Optical Society of America.

  4. Revealing the radial modes in vortex beams

    CSIR Research Space (South Africa)

    Sephton, Bereneice C

    2016-10-01

    Full Text Available is neglected in this generation approach. Here, we show that a consequence of this is that vortex beams carry very little energy in the desired zeroth radial order, as little as only a few percent of the incident power. We demonstrate this experimentally...

  5. Computer control of the beam transport system of the Chalk River electron test accelerator

    International Nuclear Information System (INIS)

    McMichael, G.E.; Kidner, S.H.; Fraser, J.S.

    1977-05-01

    The beam transport system of the Chalk River Electron Test Accelerator comprises steering coils and solenoidal focusing magnets driven by voltage-programmed, current-regulated power supplies. This report describes the beam transport and beam diagnostics systems presently in use. The computer controls all beam transport magnets from a single, allocatable control knob. The system is currently being expanded to two knobs and two readouts. (author)

  6. Attitudes toward expanding nurses' authority.

    Science.gov (United States)

    Kerzman, Hana; Van Dijk, Dina; Eizenberg, Limor; Khaikin, Rut; Phridman, Shoshi; Siman-Tov, Maya; Goldberg, Shoshi

    2015-01-01

    In recent years, an increasing number of care procedures previously under the physician's authority have been placed in the hands of registered nurses. The purpose of this study was to examine the attitudes of nurses towards expanding nurses' authority and the relationships between these attitudes and job satisfaction facets, professional characteristics, and demographics. A cross-sectional study was conducted between 2010 and 2011 in three major medical centers in Israel. Participants included 833 nurses working in 89 departments. Attitudes toward the expansion of nurses' authority were assessed by self-report questionnaire, as well as job satisfaction facets including perception of professional autonomy, nurse-physician working relations, workload and burnout, perceptions of quality of care, and nursing staff satisfaction at work. Nurses reported positive attitudes toward the expansion of nurses' authority and moderate attitudes for interpretation of diagnostic tests in selected situations. The results of multivariate regression analyses demonstrate that the nurses' satisfaction from professional autonomy and work relations were the most influential factors in explaining their attitudes toward the expansion of nurses' authority. In addition, professionally young nurses tend to be more positive regarding changes in nurses' authority. In the Israeli reality of a nurse's shortage, we are witnessing professional transitions toward expansion of the scope of nurses' accountability and decision-making authority. The current research contributes to our understanding of attitudes toward the expansion of nurses' authority among the nursing staffs. The findings indicate the necessity of redefining the scope of nursing practice within the current professional context.

  7. Possibility of high efficient beam extraction from the CERN SPS with a bent crystal. Simulation results

    Energy Technology Data Exchange (ETDEWEB)

    Scandale, W. [CERN, European Organization for Nuclear Research, CH-1211 Geneva 23 (Switzerland); Laboratoire de l' AccelerateurLineaire (LAL), Universite Paris SudOrsay, Orsay (France); INFN Sezione di Roma, Piazzale Aldo Moro 2, 00185 Rome (Italy); Kovalenko, A.D.; Taratin, A.M. [Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region (Russian Federation)

    2017-03-11

    The extraction of the SPS beam of 270 GeV/c protons assisted by a bent crystal was studied by simulation. Two methods for delivering the SPS beam onto a crystal were considered: transverse diffusion and orbit bump of the beam. It was shown that the main condition for high efficient beam extraction with a bent crystal, which is a small divergence of the incident beam, can be fulfilled. Extraction efficiency up to 99% can be reached for both methods of the beam delivering. The irradiation of the electrostatic septum wires during the beam extraction can be considerably reduced.

  8. Electron beam control for barely separated beams

    Energy Technology Data Exchange (ETDEWEB)

    Douglas, David R.; Ament, Lucas J. P.

    2017-04-18

    A method for achieving independent control of multiple beams in close proximity to one another, such as in a multi-pass accelerator where coaxial beams are at different energies, but moving on a common axis, and need to be split into spatially separated beams for efficient recirculation transport. The method for independent control includes placing a magnet arrangement in the path of the barely separated beams with the magnet arrangement including at least two multipole magnets spaced closely together and having a multipole distribution including at least one odd multipole and one even multipole. The magnetic fields are then tuned to cancel out for a first of the barely separated beams to allow independent control of the second beam with common magnets. The magnetic fields may be tuned to cancel out either the dipole component or tuned to cancel out the quadrupole component in order to independently control the separate beams.

  9. Literature in Focus Beta Beams: Neutrino Beams

    CERN Multimedia

    2009-01-01

    By Mats Lindroos (CERN) and Mauro Mezzetto (INFN Padova, Italy) Imperial Press, 2009 The beta-beam concept for the generation of electron neutrino beams was first proposed by Piero Zucchelli in 2002. The idea created quite a stir, challenging the idea that intense neutrino beams only could be produced from the decay of pions or muons in classical neutrino beams facilities or in future neutrino factories. The concept initially struggled to make an impact but the hard work by many machine physicists, phenomenologists and theoreticians over the last five years has won the beta-beam a well-earned position as one of the frontrunners for a possible future world laboratory for high intensity neutrino oscillation physics. This is the first complete monograph on the beta-beam concept. The book describes both technical aspects and experimental aspects of the beta-beam, providing students and scientists with an insight into the possibilities o...

  10. Beam Techniques - Beam Control and Manipulation

    Energy Technology Data Exchange (ETDEWEB)

    Minty, Michiko G

    2003-04-24

    We describe commonly used strategies for the control of charged particle beams and the manipulation of their properties. Emphasis is placed on relativistic beams in linear accelerators and storage rings. After a brief review of linear optics, we discuss basic and advanced beam control techniques, such as transverse and longitudinal lattice diagnostics, matching, orbit correction and steering, beam-based alignment, and linac emittance preservation. A variety of methods for the manipulation of particle beam properties are also presented, for instance, bunch length and energy compression, bunch rotation, changes to the damping partition number, and beam collimation. The different procedures are illustrated by examples from various accelerators. Special topics include injection and extraction methods, beam cooling, spin transport and polarization.

  11. Energy dependent charge spread function in a dedicated synchrotron beam pnCCD detector

    Energy Technology Data Exchange (ETDEWEB)

    Yousef, Hazem

    2011-05-20

    A scan on the pixel edges is the method which is used to resolve the electron cloud size in the pixel array of the pnCCD detector. The EDR synchrotron radiation in BESSY is the source of the X-ray photons which are used in the scans. The radius of the electron cloud as a function of the impinging photon energy is analyzed. The angle of incidence of the X-ray beam is employed in the measurements. The measurements are validated by the numerical simulation models. The inclined X-ray track leads to distribute the electron clouds in a certain number of pixels according to the incident angle of the X-ray beam. The pixels detect different electron clouds according to their generation position in the detector bulk. A collimated X-ray beam of 12.14 keV is used in the measurements with 30 and 40 entrance angles. It is shown that the two factors that leads to expand the electron clouds namely the diffusion and the mutual electrostatic repulsion can be separated from the measured electron clouds. It is noticed as well that the influence of the mutual electrostatic repulsion dominates the cloud expansion over the diffusion process in the collection time of the detector. The perpendicular X-ray track leads to determine the average radius of the electron cloud per photon energy. The results show that the size of the electron clouds (RMS) in the energy range of [5.0-21.6] keV is smaller than the pixel size. (orig.)

  12. Energy dependent charge spread function in a dedicated synchrotron beam pnCCD detector

    International Nuclear Information System (INIS)

    Yousef, Hazem

    2011-01-01

    A scan on the pixel edges is the method which is used to resolve the electron cloud size in the pixel array of the pnCCD detector. The EDR synchrotron radiation in BESSY is the source of the X-ray photons which are used in the scans. The radius of the electron cloud as a function of the impinging photon energy is analyzed. The angle of incidence of the X-ray beam is employed in the measurements. The measurements are validated by the numerical simulation models. The inclined X-ray track leads to distribute the electron clouds in a certain number of pixels according to the incident angle of the X-ray beam. The pixels detect different electron clouds according to their generation position in the detector bulk. A collimated X-ray beam of 12.14 keV is used in the measurements with 30 and 40 entrance angles. It is shown that the two factors that leads to expand the electron clouds namely the diffusion and the mutual electrostatic repulsion can be separated from the measured electron clouds. It is noticed as well that the influence of the mutual electrostatic repulsion dominates the cloud expansion over the diffusion process in the collection time of the detector. The perpendicular X-ray track leads to determine the average radius of the electron cloud per photon energy. The results show that the size of the electron clouds (RMS) in the energy range of [5.0-21.6] keV is smaller than the pixel size. (orig.)

  13. Underling modification in ion beam induced Si wafers

    International Nuclear Information System (INIS)

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

    2005-01-01

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

  14. Beam test of CSES silicon strip detector module

    Science.gov (United States)

    Zhang, Da-Li; Lu, Hong; Wang, Huan-Yu; Li, Xin-Qiao; Xu, Yan-Bing; An, Zheng-Hua; Yu, Xiao-xia; Wang, Hui; Shi, Feng; Wang, Ping; Zhao, Xiao-Yun

    2017-05-01

    The silicon-strip tracker of the China Seismo-Electromagnetic Satellite (CSES) consists of two double-sided silicon strip detectors (DSSDs) which provide incident particle tracking information. A low-noise analog ASIC VA140 was used in this study for DSSD signal readout. A beam test on the DSSD module was performed at the Beijing Test Beam Facility of the Beijing Electron Positron Collider (BEPC) using a 400-800 MeV/c proton beam. The pedestal analysis results, RMSE noise, gain correction, and intensity distribution of incident particles of the DSSD module are presented. Supported by the XXX Civil Space Programme

  15. Expanding the Interaction Equivalency Theorem

    Directory of Open Access Journals (Sweden)

    Brenda Cecilia Padilla Rodriguez

    2015-06-01

    Full Text Available Although interaction is recognised as a key element for learning, its incorporation in online courses can be challenging. The interaction equivalency theorem provides guidelines: Meaningful learning can be supported as long as one of three types of interactions (learner-content, learner-teacher and learner-learner is present at a high level. This study sought to apply this theorem to the corporate sector, and to expand it to include other indicators of course effectiveness: satisfaction, knowledge transfer, business results and return on expectations. A large Mexican organisation participated in this research, with 146 learners, 30 teachers and 3 academic assistants. Three versions of an online course were designed, each emphasising a different type of interaction. Data were collected through surveys, exams, observations, activity logs, think aloud protocols and sales records. All course versions yielded high levels of effectiveness, in terms of satisfaction, learning and return on expectations. Yet, course design did not dictate the types of interactions in which students engaged within the courses. Findings suggest that the interaction equivalency theorem can be reformulated as follows: In corporate settings, an online course can be effective in terms of satisfaction, learning, knowledge transfer, business results and return on expectations, as long as (a at least one of three types of interaction (learner-content, learner-teacher or learner-learner features prominently in the design of the course, and (b course delivery is consistent with the chosen type of interaction. Focusing on only one type of interaction carries a high risk of confusion, disengagement or missed learning opportunities, which can be managed by incorporating other forms of interactions.

  16. ISR beam scrapers

    CERN Multimedia

    CERN PhotoLab

    1972-01-01

    Beam scrapers seen in the direction of the beam. The two horizontal scraper foils are near the centre of the beam pipe andthe two scrapers for protection of the vacuum chamber are further outside. In the lower part of the beam pipe is the vertical halo scraping blade.

  17. Telecommunication using muon beams

    International Nuclear Information System (INIS)

    Arnold, R.C.

    1976-01-01

    Telecommunication is effected by generating a beam of mu mesons or muons, varying a property of the beam at a modulating rate to generate a modulated beam of muons, and detecting the information in the modulated beam at a remote location

  18. Analysis of orthotropic beams

    Science.gov (United States)

    Jen Y. Liu; S. Cheng

    1979-01-01

    A plane-stress analysis of orthotropic or isotropic beams is presented. The loading conditions considered are: (1) a concentrated normal load arbitrarily located on the beam, and (2) a distributed normal load covering an arbitrary length of the beam. exhibit close agreement with existing experimental data from Sitka spruce beams. Other loading conditions can similarly...

  19. Telecommunication using muon beams

    Science.gov (United States)

    Arnold, Richard C.

    1976-01-01

    Telecommunication is effected by generating a beam of mu mesons or muons, varying a property of the beam at a modulating rate to generate a modulated beam of muons, and detecting the information in the modulated beam at a remote location.

  20. Monte Carlo calculations for beam dump shield design for K-130 cyclotron at VECC

    International Nuclear Information System (INIS)

    Chatterjee, S.; Banerjee, K.; Roy, Pratap; Bhattacharya, C.; Bhattacharya, S.; Bandyopadhyay, T.

    2013-01-01

    In any accelerator based nuclear physics experiment most of incident beam passes through the target material and stopped in the beam dump. So the beam dump becomes the major source of neutron and γ-radiations. This contribution is much larger than that of actual neutron and γ-rays produced from the nuclear reactions with target nuclei

  1. Acoustic beam splitting in a sonic crystal around a directional band gap

    International Nuclear Information System (INIS)

    Cicek Ahmet; Kaya Olgun Adem; Ulug Bulent

    2013-01-01

    Beam splitting upon refraction in a triangular sonic crystal composed of aluminum cylinders in air is experimentally and numerically demonstrated to occur due to finite source size, which facilitates circumvention of a directional band gap. Experiments reveal that two distinct beams emerge at crystal output, in agreement with the numerical results obtained through the finite-element method. Beam splitting occurs at sufficiently-small source sizes comparable to lattice periodicity determined by the spatial gap width in reciprocal space. Split beams propagate in equal amplitude, whereas beam splitting is destructed for oblique incidence above a critical incidence angle

  2. LANSCE beam current limiter

    International Nuclear Information System (INIS)

    Gallegos, F.R.

    1996-01-01

    The Radiation Security System (RSS) at the Los Alamos Neutron Science Center (LANSCE) provides personnel protection from prompt radiation due to accelerated beam. Active instrumentation, such as the Beam Current Limiter, is a component of the RSS. The current limiter is designed to limit the average current in a beam line below a specific level, thus minimizing the maximum current available for a beam spill accident. The beam current limiter is a self-contained, electrically isolated toroidal beam transformer which continuously monitors beam current. It is designed as fail-safe instrumentation. The design philosophy, hardware design, operation, and limitations of the device are described

  3. The beam dump tunnels

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    In these images workers are digging the tunnels that will be used to dump the counter-circulating beams. Travelling just a fraction under the speed of light, the beams at the LHC will each carry the energy of an aircraft carrier travelling at 12 knots. In order to dispose of these beams safely, a beam dump is used to extract the beam and diffuse it before it collides with a radiation shielded graphite target.

  4. Ion beam diagnosis

    International Nuclear Information System (INIS)

    Strehl, P.

    1994-04-01

    This report is an introduction to ion beam diagnosis. After a short description of the most important ion beam parameters measurements of the beam current by means of Faraday cups, calorimetry, and beam current transformers and measurements of the beam profile by means of viewing screens, profile grids and scanning devices, and residual gas ionization monitors are described. Finally measurements in the transverse and longitudinal phase space are considered. (HSI)

  5. Acute incidents during anaesthesia

    African Journals Online (AJOL)

    Incidents can occur during induction, maintenance and emergence from anaesthesia. The following acute critical incidents are discussed in this article: • Anaphylaxis. • Aspiration ..... Already used in South Africa and Malawi, a scale-up of the technique is under way in Tanzania, Rwanda and Ghana. The report found that.

  6. Reflectors Made from Membranes Stretched Between Beams

    Science.gov (United States)

    Dooley, Jennifer; Dragovan, Mark; Tolomeo, Jason

    2009-01-01

    Lightweight cylindrical reflectors of a proposed type would be made from reflective membranes stretched between pairs of identically curved and identically oriented end rails. In each such reflector, the curvature of the two beams would define the reflector shape required for the intended application. For example, the beams could be curved to define a reflector of parabolic cross section, so that light incident along the axis of symmetry perpendicular to the cylindrical axis would be focused to a line. In addition, by applying suitable forces to the ends of the beams, one could bend the beams to adjust the reflector surface figure to within a precision of the order of the wavelength of the radiation to be reflected. The figure depicts an example of beams shaped so that in the absence of applied forces, each would be flat on one side and would have a radius of curvature R on the opposite side. Alternatively, the curvature of the reflector-membrane side could be other than circular. In general, the initial curvature would be chosen to optimize the final reflector shape. Then by applying forces F between the beam ends in the positions and orientations shown in the figure, one could bend beams to adjust their shape to a closer approximation of the desired precise circular or noncircular curvature.

  7. Radiological incidents in radiotherapy

    International Nuclear Information System (INIS)

    Hobzova, L.; Novotny, J.

    2008-01-01

    In many countries a reporting system of radiological incidents to national regulatory body exists and providers of radiotherapy treatment are obliged to report all major and/or in some countries all incidents occurring in institution. State Office for Nuclear Safety (SONS) is providing a systematic guidance for radiotherapy departments from 1997 by requiring inclusion of radiation safety problems into Quality assurance manual, which is the basic document for obtaining a license of SONS for handling with sources of ionizing radiation. For that purpose SONS also issued the recommendation 'Introduction of QA system for important sources in radiotherapy-radiological incidents' in which the radiological incidents are defined and the basic guidance for their classification (category A, B, C, D), investigation and reporting are given. At regular periods the SONS in co-operation with radiotherapy centers is making a survey of all radiological incidents occurring in institutions and it is presenting obtained information in synoptic communication (2003 Motolske dny, 2005 Novy Jicin). This presentation is another summary report of radiological incidents that occurred in our radiotherapy institutions during last 3 years. Emphasis is given not only to survey and statistics, but also to analysis of reasons of the radiological incidents and to their detection and prevention. Analyses of incidents in radiotherapy have led to a much broader understanding of incident causation. Information about the error should be shared as early as possible during or after investigation by all radiotherapy centers. Learning from incidents, errors and near misses should be a part of improvement of the QA system in institutions. Generally, it is recommended that all radiotherapy facilities should participate in the reporting, analyzing and learning system to facilitate the dissemination of knowledge throughout the whole country to prevent errors in radiotherapy.(authors)

  8. Characterization of low energy radioactive beams using direct reactions

    DEFF Research Database (Denmark)

    Johansen, J.G.; Fraser, M.A.; Bildstein, V.

    2013-01-01

    of an accelerated radioactive beam produced at ISOLDE. We use data from an experiment with an 11Be beam incident on a deuteron target producing 10Be from a (d,t) reaction. The T-REX Si detector array was used for particle detection, but the technique is applicable for other setups.......We demonstrate a new technique to determine the beam structure of low energy radioactive beams using coincidence events from a direct reaction. The technique will be described and tested using Geant4 simulations. We use the technique to determine for the first time the width, divergence and energy...

  9. Flexible PVC flame retarded with expandable graphite

    CSIR Research Space (South Africa)

    Focke, WW

    2014-02-01

    Full Text Available The utility of expandable graphite as a flame retardant for PVC, plasticized with 60 phr of a phosphate ester, was investigated. Cone calorimeter results, at a radiant flux of 35 kW m 2, revealed that adding only 5 wt.% expandable graphite lowered...

  10. Beam diagnostics for low energy beams

    Directory of Open Access Journals (Sweden)

    J. Harasimowicz

    2012-12-01

    Full Text Available Low-energetic ion and antimatter beams are very attractive for a number of fundamental studies. The diagnostics of such beams, however, is a challenge due to low currents down to only a few thousands of particles per second and significant fraction of energy loss in matter at keV beam energies. A modular set of particle detectors has been developed to suit the particular beam diagnostic needs of the ultralow-energy storage ring (USR at the future facility for low-energy antiproton and ion research, accommodating very low beam intensities at energies down to 20 keV. The detectors include beam-profile monitors based on scintillating screens and secondary electron emission, sensitive Faraday cups for absolute intensity measurements, and capacitive pickups for beam position monitoring. In this paper, the design of all detectors is presented in detail and results from beam measurements are shown. The resolution limits of all detectors are described and options for further improvement summarized. Whilst initially developed for the USR, the instrumentation described in this paper is also well suited for use in other low-intensity, low-energy accelerators, storage rings, and beam lines.

  11. Revisit of combined parallel-beam/cone-beam or fan-beam/cone-beam imaging.

    Science.gov (United States)

    Zeng, Gengsheng L

    2013-10-01

    This aim of this paper is to revisit the parallel-beam/cone-beam or fan-beam/cone-beam imaging configuration, and to investigate whether this configuration has any advantages. Twenty years ago, it was suggested to simultaneously use a parallel-beam (or a fan-beam) collimator and a cone-beam collimator to acquire single photon emission computed tomography data. The motivation was that the parallel-beam (or the fan-beam) collimator can provide sufficient sampling, while the cone-beam collimator is able to provide higher photon counts. Even with higher total counts, this hybrid system does not give significant improvement (if any) in terms of image noise and artifacts reduction. If a conventional iterative maximum-likelihood expectation-maximization algorithm is used to reconstruct the image, the resultant reconstruction may be worse than the parallel-beam-only (or fan-beam-only) system. This paper uses the singular value decomposition (SVD) analysis to explain this phenomenon. The SVD results indicate that the parallel-beam-only and the fan-beam-only system outperform the combined systems. The optimal imaging system does not necessary to be the one that generates the projections with highest signal-to-noise ratio and best resolution.

  12. Low current beam techniques

    Energy Technology Data Exchange (ETDEWEB)

    Saint, A.; Laird, J.S.; Bardos, R.A.; Legge, G.J.F. [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Nishijima, T.; Sekiguchi, H. [Electrotechnical Laboratory, Tsukuba (Japan).

    1993-12-31

    Since the development of Scanning Transmission Microscopy (STIM) imaging in 1983 many low current beam techniques have been developed for the scanning (ion) microprobe. These include STIM tomography, Ion Beam Induced Current, Ion Beam Micromachining and Microlithography and Ionoluminense. Most of these techniques utilise beam currents of 10{sup -15} A down to single ions controlled by beam switching techniques This paper will discuss some of the low beam current techniques mentioned above, and indicate, some of their recent applications at MARC. A new STIM technique will be introduced that can be used to obtain Z-contrast with STIM resolution. 4 refs., 3 figs.

  13. Time to Grow: Year Two Report on ExpandED Schools. A TASC Report

    Science.gov (United States)

    Traill, Saskia; Brohawn, Katie

    2014-01-01

    An analysis of data from the second year of The After-School Corporation's (TASC's) national demonstration of an expanded school day for elementary and middle school students shows that ExpandED Schools improved school culture, decreased rates of students' chronic absenteeism and helped students develop positive learning habits and attitudes.…

  14. Studies on normal incidence backscattering in nodule areas using the multibeam-hydrosweep system

    Digital Repository Service at National Institute of Oceanography (India)

    Pathak, D.; Chakraborty, B.

    The acoustic response from areas of varying nodule abundance and number densities in the Central Indian Ocean has been studied by using the echo peak amplitudes of the normal incidence beam in the Multibeam Hydrosweep system. It is observed...

  15. Comprehensive proton dose algorithm using pencil beam redefinition and recursive dynamic splitting

    OpenAIRE

    Gottschalk, Bernard

    2016-01-01

    We compute, from first principles, the absolute dose or fluence distribution per incident proton charge in a known heterogeneous terrain exposed to known proton beams. The algorithm is equally amenable to scattered or scanned beams. All objects in the terrain (including collimators) are sliced into slabs, of any convenient thickness, perpendicular to the nominal beam direction. Transport is by standard Fermi-Eyges theory. Transverse heterogeneities are handled by breaking up pencil beams (PBs...

  16. Spatial modifications of three-dimensional elliptic Gaussian beam scattered by two-dimensional periodic array.

    Directory of Open Access Journals (Sweden)

    A. Gribovsky

    2012-06-01

    Full Text Available The diffraction problem of a three-dimensional elliptic p- polarized Gaussian beam on an aperture array of rectangular holes is solved. The new algorithm for the solution of three-dimensional scattering problems of linearly polarized wave beams on two-dimensional periodic structures is offered. The given algorithm allows exploring of wave beams with any allocation of a field on cross section. The case of oblique incidence of linearly polarized elliptic Gaussian wave beam on two-dimensional periodic structure is viewed. As structure the rectangular waveguides phased antenna array is chosen. The elliptic shape of a beam cross section gives the chance to proportion energy of an incident field in a plane of an antenna array in the chosen direction. The frequency dependence of the reflection coefficient intensity for the Gaussian beam is calculated. For the analysis of patterns of the reflected and transmitted beams in a far zone the frequencies on which the strongest interaction between next waveguides channels is observed have been chosen. Dynamics of patterns transformation of the reflected and transmitted beams depending on the form of cross-section and a polarization direction of an incident beam on different frequencies is investigated. It is determined that shape of the pattern of reflected and transmitted beams (symmetry, asymmetry, bifurcation, amplitude, width depends on chosen spatial orientation of the ellipse axes of the cross section in the incident beam. Frequency ranges, in which the form of the reflected and transmitted beams is not Gaussian, are defined. The nature of transformation of the patterns of scattered beams was examined. Narrowing effect of the pattern of transmitted beam and deformation of the pattern of reflected beam is detected. A physical explanation of these effects is given. The results are presented in the form of two- and three-dimensional patterns of the scattered field of beams in the far field.

  17. Beam Dynamics and Beam Losses - Circular Machines

    CERN Document Server

    Kain, V

    2016-01-01

    A basic introduction to transverse and longitudinal beam dynamics as well as the most relevant beam loss mechanisms in circular machines will be presented in this lecture. This lecture is intended for physicists and engineers with little or no knowledge of this subject.

  18. T10 Beam Studies & Beam Simulation

    CERN Document Server

    Bergmann, Michael Georges; Van Dijk, Maarten; CERN. Geneva. EN Department

    2017-01-01

    In order to test detector components before their installation in actual experiments, one uses test beams in which one can control particle typ, momentum and size to high degree. For this project the focus of a secondary beam at T10 in the East Area at CERN was analysed using an AZALEA telescope from DESY.

  19. Incorporating prior knowledge into beam orientation optimization in IMRT

    International Nuclear Information System (INIS)

    Pugachev, Andrei M.S.; Lei Xing

    2002-01-01

    Purpose: Selection of beam configuration in currently available intensity-modulated radiotherapy (IMRT) treatment planning systems is still based on trial-and-error search. Computer beam orientation optimization has the potential to improve the situation, but its practical implementation is hindered by the excessive computing time associated with the calculation. The purpose of this work is to provide an effective means to speed up the beam orientation optimization by incorporating a priori geometric and dosimetric knowledge of the system and to demonstrate the utility of the new algorithm for beam placement in IMRT. Methods and Materials: Beam orientation optimization was performed in two steps. First, the quality of each possible beam orientation was evaluated using beam's-eye-view dosimetrics (BEVD) developed in our previous study. A simulated annealing algorithm was then employed to search for the optimal set of beam orientations, taking into account the BEVD scores of different incident beam directions. During the calculation, sampling of gantry angles was weighted according to the BEVD score computed before the optimization. A beam direction with a higher BEVD score had a higher probability of being included in the trial configuration, and vice versa. The inclusion of the BEVD weighting in the stochastic beam angle sampling process made it possible to avoid spending valuable computing time unnecessarily at 'bad' beam angles. An iterative inverse treatment planning algorithm was used for beam intensity profile optimization during the optimization process. The BEVD-guided beam orientation optimization was applied to an IMRT treatment of paraspinal tumor. The advantage of the new optimization algorithm was demonstrated by comparing the calculation with the conventional scheme without the BEVD weighting in the beam sampling. Results: The BEVD tool provided useful guidance for the selection of the potentially good directions for the beams to incident and was used

  20. Critical incident stress management.

    Science.gov (United States)

    Lim, J J; Childs, J; Gonsalves, K

    2000-10-01

    Recent studies have indicated implementation of the CISM Program has impacted and reduced the cost of workers' compensation claims for stress related conditions and the number of lost work days (Ott, 1997; Western Management Consultants, 1996). Occupational health professionals need to be ready to develop and implement a comprehensive critical incident stress management process in anticipation of a major event. The ability to organize, lead, or administer critical incident stress debriefings for affected employees is a key role for the occupational health professional. Familiarity with these concepts and the ability to identify a critical incident enhances value to the business by mitigating the stress and impact to the workplace. Critical Incident Stress Management Systems have the potential for decreasing stress and restoring employees to normal life function--a win/win situation for both the employees and the organization.

  1. Marine Animal Incident Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Large whale stranding, death, ship strike and entanglement incidents are all recorded to monitor the health of each population and track anthropogenic factors that...

  2. Police Incident Blotter (Archive)

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — The Police Blotter Archive contains crime incident data after it has been validated and processed to meet Uniform Crime Reporting (UCR) standards, published on a...

  3. Prediction of Safety Incidents

    Data.gov (United States)

    National Aeronautics and Space Administration — Safety incidents, including injuries, property damage and mission failures, cost NASA and contractors thousands of dollars in direct and indirect costs. This project...

  4. 2011 Japanese Nuclear Incident

    Science.gov (United States)

    EPA’s RadNet system monitored the environmental radiation levels in the United States and parts of the Pacific following the Japanese Nuclear Incident. Learn about EPA’s response and view historical laboratory data and news releases.

  5. Accelerator beam application in science and industry

    International Nuclear Information System (INIS)

    Hagiwara, M.

    1996-01-01

    Various accelerator beams are being used widely in science and industry. The area of their applications is so wide and rapidly expanding. This paper focuses on recent efforts made in the field of radiation chemistry, especially in materials development using electron and ion beams. Concerning the applications of electron beams, synthesis of SiC fibers, improvement of radiation resistance of polytetrafluoroethylene (PTFE) and preparation of an adsorbent for uranium recovery from sea water were described. In the synthesis of SiC, the electron beams were used effectively to cross-link precursor fibers to prevent their deformation upon heating for their pyrolysis to SiC fibers. The improvement of radiation resistance of PTFE was resulted successfully by its crosslinking. As to the preparation of the adsorbent for uranium recovery, chelating resins containing amidoxime groups were shown to work as a good adsorbent of uranium from sea water. The Takasaki Radiation Chemistry Research Establishment of JAERI completed the accelerator facility named TIARA for R and D of ion beam applications three years ago. Some results were presented on the studies about radiation effects on solar cells and LSIs for space use and synthesis of functional materials. Radiation resistance of solar cells was tested with both electron and proton beams using a beam scanning technique for the irradiation to a wide area, and ultra-fast transient current induced by heavy ion microbeam was measured for studies on mechanisms of single event upset (SEU) in LSIs. In the synthesis of organic functional materials, a temperature responsive particle track membrane was developed. Techniques for RBS and NRA using heavy ion beams were established for analyzing structures of multi-layered materials. Single crystalline thin film of diamond was successfully formed on Si substrate under the deposition of mass separated C-12 ions of 100 eV. (author)

  6. BEAMS3D Neutral Beam Injection Model

    Energy Technology Data Exchange (ETDEWEB)

    Lazerson, Samuel

    2014-04-14

    With the advent of applied 3D fi elds in Tokamaks and modern high performance stellarators, a need has arisen to address non-axisymmetric effects on neutral beam heating and fueling. We report on the development of a fully 3D neutral beam injection (NBI) model, BEAMS3D, which addresses this need by coupling 3D equilibria to a guiding center code capable of modeling neutral and charged particle trajectories across the separatrix and into the plasma core. Ionization, neutralization, charge-exchange, viscous velocity reduction, and pitch angle scattering are modeled with the ADAS atomic physics database [1]. Benchmark calculations are presented to validate the collisionless particle orbits, neutral beam injection model, frictional drag, and pitch angle scattering effects. A calculation of neutral beam heating in the NCSX device is performed, highlighting the capability of the code to handle 3D magnetic fields.

  7. Successful Beam-Beam Tuneshift Compensation

    Energy Technology Data Exchange (ETDEWEB)

    Bishofberger, Kip Aaron [Univ. of California, Los Angeles, CA (United States)

    2005-01-01

    The performance of synchrotron colliders has been limited by the beam-beam limit, a maximum tuneshift that colliding bunches could sustain. Due to bunch-to-bunch tune variation and intra-bunch tune spread, larger tuneshifts produce severe emittance growth. Breaking through this constraint has been viewed as impossible for several decades. This dissertation introduces the physics of ultra-relativistic synchrotrons and low-energy electron beams, with emphasis placed on the limits of the Tevatron and the needs of a tuneshift-compensation device. A detailed analysis of the Tevatron Electron Lens (TEL) is given, comparing theoretical models to experimental data whenever possible. Finally, results of Tevatron operations with inclusion of the TEL are presented and analyzed. It is shown that the TEL provides a way to shatter the previously inescapable beam-beam limit.

  8. Information Security Incident Management

    Directory of Open Access Journals (Sweden)

    D. I. Persanov

    2010-03-01

    Full Text Available The present report highlights the points of information security incident management in an enterprise. Some aspects of the incident and event classification are given. The author presents his view of the process scheme over the monitoring and processing information security events. Also, the report determines a few critical points of the listed process and gives the practical recommendations over its development and optimization.

  9. Evaporation studies of liquid oxide fuel at very high temperatures using laser beam heating

    International Nuclear Information System (INIS)

    Bober, M.; Breitung, W.; Karow, H.U.; Schretzmann, K.

    1976-11-01

    Evaporation experiments with oxide fuel are carried out based laser beam heating of the fuel specimen surface. The measuring quantities are the recoil momentum of the target, the evaporation area, the evaporation time and the mass and momentum of the supersonic vapor jet expanding into vacuum, and the thermal radiation density of the evaporating surface. From the mechanical measuring quantities we derive the vapor pressure of the target material and, in a first approach, also the evaporation temperature by applying a gas dynamic evaluation model. In a second approach, after having measured the spectral emissivity of liquid UO 2 at 633 nm, we determine the evaporation temperature at the liquid surface also from its thermal radiation. For the determination of the vapor pressure from the measured quantities a gas dynamic evaluation model has been developed. An application limit of the measuring technique is given by onset of plasma interaction of the vapor plume with the incident laser beam at temperatures above 4500 K. Experimental values for the saturated vapor pressure of UO 2 are presented, determined from three series of laser evaporation measurements obtained at temperatures around 3500 K, 3950 K, and 4200 K. The average vapor pressures found are 0.6 bar, 3 bar, and 7 bar, respectively. Laser vapor pressure measurements performed by other authors and theoretical extrapolations of the UO 2 vapor pressure curve known from literature show fairly good agreement within their confidence interval with the vapor pressure measurements reported here. (orig./HR) [de

  10. A-coupled-expanding and distributional chaos

    International Nuclear Information System (INIS)

    Kim, Cholsan; Ju, Hyonhui; Chen, Minghao; Raith, Peter

    2015-01-01

    The concept of A-coupled-expanding maps is one of the more natural and useful ideas generalized from the horseshoe map which is commonly known as a criterion of chaos. It is well known that distributional chaos is one of the concepts which reflect strong chaotic behavior. In this paper, we focus on the relationship between A-coupled-expanding and distributional chaos. We prove two theorems which give sufficient conditions for a strictly A-coupled-expanding map to be distributionally chaotic in the senses of two kinds, where A is an m × m irreducible transition matrix

  11. Grazing Incidence Neutron Optics

    Science.gov (United States)

    Gubarev, Mikhail V. (Inventor); Ramsey, Brian D. (Inventor); Engelhaupt, Darell E. (Inventor)

    2013-01-01

    Neutron optics based on the two-reflection geometries are capable of controlling beams of long wavelength neutrons with low angular divergence. The preferred mirror fabrication technique is a replication process with electroform nickel replication process being preferable. In the preliminary demonstration test an electroform nickel optics gave the neutron current density gain at the focal spot of the mirror at least 8 for neutron wavelengths in the range from 6 to 20.ANG.. The replication techniques can be also be used to fabricate neutron beam controlling guides.

  12. Beam Loss in Linacs

    CERN Document Server

    Plum, M.A.

    2016-01-01

    Beam loss is a critical issue in high-intensity accelerators, and much effort is expended during both the design and operation phases to minimize the loss and to keep it to manageable levels. As new accelerators become ever more powerful, beam loss becomes even more critical. Linacs for H- ion beams, such as the one at the Oak Ridge Spallation Neutron Source, have many more loss mechanisms compared to H+ (proton) linacs, such as the one being designed for the European Spallation Neutron Source. Interesting H- beam loss mechanisms include residual gas stripping, H+ capture and acceleration, field stripping, black-body radiation and the recently discovered intra-beam stripping mechanism. Beam halo formation, and ion source or RF turn on/off transients, are examples of beam loss mechanisms that are common for both H+ and H- accelerators. Machine protection systems play an important role in limiting the beam loss.

  13. Beam scanning system

    International Nuclear Information System (INIS)

    Enge, H.A.

    1977-01-01

    A system for deflecting a beam of particles having different momenta, preferably through a 90 0 angle, so as to cause the beam to impinge upon a moving target and to scan across the target is described. The system includes a means responsive to a beam from a suitable source for causing the beam to periodically scan in a scanning plane and further means for deflecting the periodically scanned beam through the desired angle in a deflection plane so that the deflected beam impinges on the target. Means are included in the system for reducing the momentum dispersion at the target in both the deflection and the scanning planes and for spatially focussing the beam so as to produce a desired beam diameter at the target

  14. Reconstruction of laser beam wavefronts based on mode analysis

    CSIR Research Space (South Africa)

    Schulze, C

    2013-07-01

    Full Text Available . Experimental Setup To measure the influence of defined Zernike aberra- tions on a laser beam, we used an experimental setup as outlined in Fig. 3. The beam of a helium–neon laser (10 mW power, 633 nm wavelength) was expanded and collimated [ f �L 1 � � 15 mm, f.... Insets depict the shapes of the corresponding aberrations. Fig. 3. Schematic of the experimental setup to modally decom- pose differently aberrated Gaussian beams. He–Ne, helium–neon laser; L 1–5 , lenses; M, mirror; SLM 1;2, spatial light modulator...

  15. DOE's Computer Incident Advisory Capability (CIAC)

    Energy Technology Data Exchange (ETDEWEB)

    Schultz, E.

    1990-09-01

    Computer security is essential in maintaining quality in the computing environment. Computer security incidents, however, are becoming more sophisticated. The DOE Computer Incident Advisory Capability (CIAC) team was formed primarily to assist DOE sites in responding to computer security incidents. Among CIAC's other responsibilities are gathering and distributing information to DOE sites, providing training workshops, coordinating with other agencies, response teams, and vendors, creating guidelines for incident handling, and developing software tools. CIAC has already provided considerable assistance to DOE sites faced with virus infections and worm and hacker attacks, has issued over 40 information bulletins, and has developed and presented a workshop on incident handling. CIAC's experience in helping sites has produced several lessons learned, including the need to follow effective procedures to avoid virus infections in small systems and the need for sound password management and system administration in networked systems. CIAC's activity and scope will expand in the future. 4 refs.

  16. Crossed beam experiments

    International Nuclear Information System (INIS)

    Dolder, K.T.

    1976-01-01

    Many natural phenomena can only be properly understood if one has a detailed knowledge of interactions involving atoms, molecules, ions, electrons or photons. In the laboratory these processes are often studied by preparing beams of two types of particle and observing the reactions which occur when the beams intersect. Some of the more interesting of these crossed beam experiments and their results are discussed. Proposals to extend colliding beam techniques to high energy particle physics are also outlined. (author)

  17. Adapting Cognitive Task Analysis to Investigate Clinical Decision Making and Medication Safety Incidents.

    Science.gov (United States)

    Russ, Alissa L; Militello, Laura G; Glassman, Peter A; Arthur, Karen J; Zillich, Alan J; Weiner, Michael

    2017-05-03

    Cognitive task analysis (CTA) can yield valuable insights into healthcare professionals' cognition and inform system design to promote safe, quality care. Our objective was to adapt CTA-the critical decision method, specifically-to investigate patient safety incidents, overcome barriers to implementing this method, and facilitate more widespread use of cognitive task analysis in healthcare. We adapted CTA to facilitate recruitment of healthcare professionals and developed a data collection tool to capture incidents as they occurred. We also leveraged the electronic health record (EHR) to expand data capture and used EHR-stimulated recall to aid reconstruction of safety incidents. We investigated 3 categories of medication-related incidents: adverse drug reactions, drug-drug interactions, and drug-disease interactions. Healthcare professionals submitted incidents, and a subset of incidents was selected for CTA. We analyzed several outcomes to characterize incident capture and completed CTA interviews. We captured 101 incidents. Eighty incidents (79%) met eligibility criteria. We completed 60 CTA interviews, 20 for each incident category. Capturing incidents before interviews allowed us to shorten the interview duration and reduced reliance on healthcare professionals' recall. Incorporating the EHR into CTA enriched data collection. The adapted CTA technique was successful in capturing specific categories of safety incidents. Our approach may be especially useful for investigating safety incidents that healthcare professionals "fix and forget." Our innovations to CTA are expected to expand the application of this method in healthcare and inform a wide range of studies on clinical decision making and patient safety.

  18. An Electromagnetic Beam Converter

    DEFF Research Database (Denmark)

    2009-01-01

    The present invention relates to an electromagnetic beam converter and a method for conversion of an input beam of electromagnetic radiation having a bell shaped intensity profile a(x,y) into an output beam having a prescribed target intensity profile l(x',y') based on a further development...

  19. Beams 92: Proceedings

    International Nuclear Information System (INIS)

    Mosher, D.; Cooperstein, G.

    1993-01-01

    This report contains papers on the following topics: Ion beam papers; electron beam, bremsstrahlung, and diagnostics papers; radiating Z- pinch papers; microwave papers; electron laser papers; advanced accelerator papers; beam and pulsed power applications papers; pulsed power papers; and these papers have been indexed separately elsewhere

  20. Radiation produced by electrons incident on molecules

    International Nuclear Information System (INIS)

    Moehlman, G.R.

    1977-01-01

    The work described in this thesis deals with light intensity measurements of emission spectra (1850-9000 A) produced by a continuous or pulsed beam of monoenergetic electrons (0 - 2000 eV) incident on a variety of molecular gases like H 2 , D 2 , H 2 O, HCl, NH 3 and several hydrocarbons. The emission spectra are dominated by fluorescence from excited fragments produced via dissociative excitation, besides fluorescence from excited parent molecules themselves. The experimental results thus obtained are expressed in terms of emission cross sections and lifetimes

  1. Manufacture of Strand Board Bonded with Disposal Expanded Polystyrene as Binder

    OpenAIRE

    Hermawan, Andi; Ohuchi, Takeshi; Fujimoto, Noboru; 大内, 毅; 藤本, 登留

    2010-01-01

    The objective of this study was to evaluate the physical and mechanical properties of strand board bonded with disposal expanded polystyrene (EPS) as binder. The strand board was manufactured using strand made from Douglas-fir beams selected from construction scrap wood. The strands were oriented, and two types of three-layer (face-core-face) strand board were manufactured: one in which the board bounded with only disposal EPS (P board), and the other in which the board bonded with disposal...

  2. Beam Expansion of Blind Spot Detection Radar Antennas Using a Radome with Defected Corrugated Inner Wall

    Directory of Open Access Journals (Sweden)

    Hayeon Kim

    2017-01-01

    Full Text Available A beam expanding radome for 76.5 GHz automotive radar antennas is presented whose inner surface is engraved with corrugations. The radar used for blind spot detection (BSD requires a very wide beam width to ensure longer time for tracking out-of-sight objects. It is found that the corrugations modulate the phase velocities of the waves along the surface, which increases beam width in the far field. In addition, defects in the corrugation increase beam width even further. The presented structure satisfies the beam width requirement while keeping a low profile.

  3. Measurement of beam energy spectrum and impurity content in high-power neutral beam injectors

    International Nuclear Information System (INIS)

    Langley, R.A.; Ryan, P.M.; Tsai, C.C.; Menon, M.M.; Botnick, E.M.; Magee, C.W.

    1985-01-01

    The energy spectrum and impurity content of a high-power neutral beam are measured by implanting the beam into high-purity silicon crystals. The depth distribution of the beam particles is then measured by secondary ion mass spectrometry (SIMS); the penetration depth is a function of the incident particle energy. This is one of the few measurement techniques that can determine neutral beam energy components directly. From the results, percentages of atomic and molecular ions in the source plasma can be inferred. Use of deuterium as the source gas provides insight into the role of residual hydrogen in the ion source and accelerating grids and in the SIMS analysis. The principal impurities are carbon and oxygen. Preliminary data indicate that carbon can originate from both methane and carbon monoxide, while oxygen can come from molecular oxygen, carbon monoxide, and water. Results are given and future plans are discussed

  4. A plasma amplifier to combine multiple beams at NIF

    Science.gov (United States)

    Kirkwood, R. K.; Turnbull, D. P.; Chapman, T.; Wilks, S. C.; Rosen, M. D.; London, R. A.; Pickworth, L. A.; Colaitis, A.; Dunlop, W. H.; Poole, P.; Moody, J. D.; Strozzi, D. J.; Michel, P. A.; Divol, L.; Landen, O. L.; MacGowan, B. J.; Van Wonterghem, B. M.; Fournier, K. B.; Blue, B. E.

    2018-05-01

    Combining laser beams in a plasma is enabled by seeded stimulated Brillouin scattering which allows cross-beam energy transfer (CBET) to occur and re-distributes the energy between beams that cross with different incident angles and small differences in wavelength [Kirkwood et al. Phys. Plasmas 4, 1800 (1997)]. Indirect-drive implosions at the National Ignition Facility (NIF) [Haynam et al. Appl. Opt. 46, 3276-3303 (2007)] have controlled drive symmetry by using plasma amplifiers to transfer energy between beams [Kirkwood et al., Plasma Phys. Controlled Fusion 55, 103001 (2013); Lindl et al., Phys. Plasmas 21, 020501 (2014); and Hurricane et al. Nature 506, 343-348 (2014)]. In this work, we show that the existing models are well enough validated by experiments to allow a design of a plasma beam combiner that, once optimized, is expected to produce a pulse of light in a single beam with the energy greatly enhanced over existing sources. The scheme combines up to 61 NIF beams with 120 kJ of available energy into a single f/20 beam with a 1 ns pulse duration and a 351 nm wavelength by both resonant and off-resonance CBET. Initial experiments are also described that have already succeeded in producing a 4 kJ, 1 ns pulse in a single beam by combination of up to eight incident pump beams containing <1.1 kJ/beam, which are maintained near resonance for CBET in a plasma that is formed by 60 pre-heating beams [Kirkwood et al., Nat. Phys. 14, 80 (2018)].

  5. Establishment of mouse expanded potential stem cells.

    Science.gov (United States)

    Yang, Jian; Ryan, David J; Wang, Wei; Tsang, Jason Cheuk-Ho; Lan, Guocheng; Masaki, Hideki; Gao, Xuefei; Antunes, Liliana; Yu, Yong; Zhu, Zhexin; Wang, Juexuan; Kolodziejczyk, Aleksandra A; Campos, Lia S; Wang, Cui; Yang, Fengtang; Zhong, Zhen; Fu, Beiyuan; Eckersley-Maslin, Melanie A; Woods, Michael; Tanaka, Yosuke; Chen, Xi; Wilkinson, Adam C; Bussell, James; White, Jacqui; Ramirez-Solis, Ramiro; Reik, Wolf; Göttgens, Berthold; Teichmann, Sarah A; Tam, Patrick P L; Nakauchi, Hiromitsu; Zou, Xiangang; Lu, Liming; Liu, Pentao

    2017-10-19

    Mouse embryonic stem cells derived from the epiblast contribute to the somatic lineages and the germline but are excluded from the extra-embryonic tissues that are derived from the trophectoderm and the primitive endoderm upon reintroduction to the blastocyst. Here we report that cultures of expanded potential stem cells can be established from individual eight-cell blastomeres, and by direct conversion of mouse embryonic stem cells and induced pluripotent stem cells. Remarkably, a single expanded potential stem cell can contribute both to the embryo proper and to the trophectoderm lineages in a chimaera assay. Bona fide trophoblast stem cell lines and extra-embryonic endoderm stem cells can be directly derived from expanded potential stem cells in vitro. Molecular analyses of the epigenome and single-cell transcriptome reveal enrichment for blastomere-specific signature and a dynamic DNA methylome in expanded potential stem cells. The generation of mouse expanded potential stem cells highlights the feasibility of establishing expanded potential stem cells for other mammalian species.

  6. Energy spectrum control for modulated proton beams

    International Nuclear Information System (INIS)

    Hsi, Wen C.; Moyers, Michael F.; Nichiporov, Dmitri; Anferov, Vladimir; Wolanski, Mark; Allgower, Chris E.; Farr, Jonathan B.; Mascia, Anthony E.; Schreuder, Andries N.

    2009-01-01

    In proton therapy delivered with range modulated beams, the energy spectrum of protons entering the delivery nozzle can affect the dose uniformity within the target region and the dose gradient around its periphery. For a cyclotron with a fixed extraction energy, a rangeshifter is used to change the energy but this produces increasing energy spreads for decreasing energies. This study investigated the magnitude of the effects of different energy spreads on dose uniformity and distal edge dose gradient and determined the limits for controlling the incident spectrum. A multilayer Faraday cup (MLFC) was calibrated against depth dose curves measured in water for nonmodulated beams with various incident spectra. Depth dose curves were measured in a water phantom and in a multilayer ionization chamber detector for modulated beams using different incident energy spreads. Some nozzle entrance energy spectra can produce unacceptable dose nonuniformities of up to ±21% over the modulated region. For modulated beams and small beam ranges, the width of the distal penumbra can vary by a factor of 2.5. When the energy spread was controlled within the defined limits, the dose nonuniformity was less than ±3%. To facilitate understanding of the results, the data were compared to the measured and Monte Carlo calculated data from a variable extraction energy synchrotron which has a narrow spectrum for all energies. Dose uniformity is only maintained within prescription limits when the energy spread is controlled. At low energies, a large spread can be beneficial for extending the energy range at which a single range modulator device can be used. An MLFC can be used as part of a feedback to provide specified energy spreads for different energies.

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

    Directory of Open Access Journals (Sweden)

    Lohse, Christian

    2015-11-01

    Full Text Available 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 and computed tomography.

  8. Analytical formula for a circular flattened Gaussian beam propagating through a misaligned paraxial ABCD optical system

    International Nuclear Information System (INIS)

    Hu Li; Cai Yangjian

    2006-01-01

    Based on the generalized diffraction integral formula for treating the propagation of a laser beam through a misaligned paraxial ABCD optical system in the cylindrical coordinate system, analytical formula for a circular flattened Gaussian beam propagating through such optical system is derived. Furthermore, an approximate analytical formula is derived for a circular flattened Gaussian beam propagating through an apertured misaligned ABCD optical system by expanding the hard aperture function as a finite sum of complex Gaussian functions. Numerical examples are given

  9. Radiation incidents in dentistry

    International Nuclear Information System (INIS)

    Lovelock, D.J.

    1996-01-01

    Most dental practitioners act as their own radiographer and radiologist, unlike their medical colleagues. Virtually all dental surgeons have a dental X-ray machine for intraoral radiography available to them and 40% of dental practices have equipment for dental panoramic tomography. Because of the low energy of X-ray equipment used in dentistry, radiation incidents tend to be less serious than those associated with other aspects of patient care. Details of 47 known incidents are given. The advent of the 1985 and 1988 Ionising Radiation Regulations has made dental surgeons more aware of the hazards of radiation. These regulations, and general health and safety legislation, have led to a few dental surgeons facing legal action. Because of the publicity associated with these court cases, it is expected that there will be a decrease in radiation incidents arising from the practice of dentistry. (author)

  10. Extension of filament propagation in water with Bessel-Gaussian beams

    International Nuclear Information System (INIS)

    Kaya, G.; Sayrac, M.; Boran, Y.; Kolomenskii, A. A.; Kaya, N.; Schuessler, H. A.; Strohaber, J.; Amani, M.

    2016-01-01

    We experimentally studied intense femtosecond pulse filamentation and propagation in water for Bessel-Gaussian beams with different numbers of radial modal lobes. The transverse modes of the incident Bessel-Gaussian beam were created from a Gaussian beam of a Ti:sapphire laser system by using computer generated hologram techniques. We found that filament propagation length increased with increasing number of lobes under the conditions of the same peak intensity, pulse duration, and the size of the central peak of the incident beam, suggesting that the radial modal lobes may serve as an energy reservoir for the filaments formed by the central intensity peak.

  11. Risk factors for radiotherapy incidents: a single institutional experience.

    Science.gov (United States)

    Ishiyama, Hiromichi; Shuto, Nobuaki; Terazaki, Tsuyoshi; Noda, Shigetoshi; Ishigami, Minoru; Yogo, Katsunori; Hayakawa, Kazushige

    2018-01-30

    We aimed to analyze risk factors for incidents occurring during the practice of external beam radiotherapy (EBRT) at a single Japanese center. Treatment data for EBRT from June 2014 to March 2017 were collected. Data from incident reports submitted during this period were reviewed. Near-miss cases were not included. Risk factors for incidents, including patient characteristics and treatment-related factors, were explored using uni- and multivariate analyses. Factors contributing to each incident were also retrospectively categorized according to the recommendations of the American Association of Physicists in Medicine (AAPM). A total of 2887 patients were treated during the study period, and 26 incidents occurred (0.90% per patient). Previous history of radiotherapy and large fraction size were identified as risk factors for incidents by univariate analysis. Only previous history of radiotherapy was detected as a risk factor in multivariate analysis. Identified categories of contributing factors were human behavior (50.0%), communication (40.6%), and technical (9.4%). The incident rate of EBRT was 0.90% per patient in our institution. Previous history of radiotherapy and large fraction size were detected as risk factors for incidents. Human behavior and communication errors were identified as contributing factors for most incidents. Copyright © 2018 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

  12. Pulling cylindrical particles using a soft-nonparaxial tractor beam

    DEFF Research Database (Denmark)

    Novitsky, Andrey; Ding, Weiqiang; Wang, Maoyan

    2017-01-01

    In order to pull objects towards the light source a single tractor beam inevitably needs to be strongly nonparaxial. This stringent requirement makes such a tractor beam somewhat hypothetical. Here we reveal that the cylindrical shape of dielectric particles can effectively mitigate...... the nonparaxiality requirements, reducing the incidence angle of the partial plane waves of the light beam down to 45 degrees and even to 30 degrees for respectively dipole and dipole-quadrupole objects. The optical pulling force attributed to the interaction of magnetic dipole and magnetic quadrupole moments...... of dielectric cylinders occurs due to the TE rather than TM polarization. Therefore, the polarization state of the incident beam can be utilized as an external control for switching between the pushing and pulling forces. The results have application values towards optical micromanipulation, transportation...

  13. Strong-strong beam-beam simulation on parallel computer

    Energy Technology Data Exchange (ETDEWEB)

    Qiang, Ji

    2004-08-02

    The beam-beam interaction puts a strong limit on the luminosity of the high energy storage ring colliders. At the interaction points, the electromagnetic fields generated by one beam focus or defocus the opposite beam. This can cause beam blowup and a reduction of luminosity. An accurate simulation of the beam-beam interaction is needed to help optimize the luminosity in high energy colliders.

  14. Strong-strong beam-beam simulation on parallel computer

    International Nuclear Information System (INIS)

    Qiang, Ji

    2004-01-01

    The beam-beam interaction puts a strong limit on the luminosity of the high energy storage ring colliders. At the interaction points, the electromagnetic fields generated by one beam focus or defocus the opposite beam. This can cause beam blowup and a reduction of luminosity. An accurate simulation of the beam-beam interaction is needed to help optimize the luminosity in high energy colliders

  15. Incidents in nuclear installations

    International Nuclear Information System (INIS)

    Franzen, L.F.; Wienhold, W.

    1976-09-01

    With reference to the incident list of the Ministry for the period 1971-74, Prof. Bechert has expressed a lot of questions and statements in a letter to the Government. The letter is quoted in full. Inadequate conclusions drawn by Prof. Bechert in connection with quotations from daily newspapers and other documents are put right. (HP) [de

  16. Lightning incidents in Mongolia

    Directory of Open Access Journals (Sweden)

    Myagmar Doljinsuren

    2015-11-01

    Full Text Available This is one of the first studies that has been conducted in Mongolia on the distribution of lightning incidents. The study covers a 10-year period from 2004 to 2013. The country records a human death rate of 15.4 deaths per 10 million people per year, which is much higher than that of many countries with similar isokeraunic level. The reason may be the low-grown vegetation observed in most rural areas of Mongolia, a surface topography, typical to steppe climate. We suggest modifications to Gomes–Kadir equation for such countries, as it predicts a much lower annual death rate for Mongolia. The lightning incidents spread over the period from May to August with the peak of the number of incidents occurring in July. The worst lightning affected region in the country is the central part. Compared with impacts of other convective disasters such as squalls, thunderstorms and hail, lightning stands as the second highest in the number of incidents, human deaths and animal deaths. Economic losses due to lightning is only about 1% of the total losses due to the four extreme weather phenomena. However, unless precautionary measures are not promoted among the public, this figure of losses may significantly increase with time as the country is undergoing rapid industrialization at present.

  17. Fire Incident Reporting Manual

    Science.gov (United States)

    1984-02-01

    the result of an incident that requires (or should require) treatment by a practitioner of medicine , a registered emergency medical technician, or a...UNANNOUNCED AIRCRAFT EMERGENCYS ~~PRIOR TO TAKE OFF OR AFTERLADN 5 FUEL OPERATIONS REQUIRING 1AREING G A FIRE10 ARRESTING GEAR’BARRIER FR . ENGAGEMENTS AND

  18. Bank Directors’ Perceptions of Expanded Auditor's Reports

    DEFF Research Database (Denmark)

    Boolaky, Pran Krishansing; Quick, Reiner

    2016-01-01

    Subsequent to the financial crisis, standard setters developed suggestions for enhancing the audit function, in order to increase financial stability. One related idea is to expand the audit report disclosed to the public, to ensure that it is fit for purpose. This study investigates the impact...... of expanded audit reports, namely information on the assurance level, materiality levels and key audit matters (KAM), on bank director perceptions of the quality of the financial statements, the audit and the audit report, as well as on their credit approval decisions. We conduct an experiment involving...... a sample of 105 bank directors and use ANCOVA to determine the predictors of bank director perceptions and decisions. Our findings suggest that disclosing the assurance level has a significantly positive impact. In contrast, we cannot demonstrate a material effect of expanding the audit report to include...

  19. Acoustics of finite asymmetric exotic beams: Examples of Airy and fractional Bessel beams

    Science.gov (United States)

    Mitri, F. G.

    2017-12-01

    The purpose of this investigation is to examine the properties of finite asymmetric exotic scalar (acoustic) beams with unusual properties using the angular spectrum decomposition in plane waves. Such beams possess intrinsic uncommon characteristics that make them attractive from the standpoint of particle manipulation, handling and rotation, and possibly other applications in particle clearing and separation. Assuming a specific apodization function at the acoustic source, the angular spectrum function is calculated and used to synthesize the radiated pressure field (i.e., excluding evanescent waves that decay away from the source) in the forward direction of wave motion (i.e., away from the source). Moreover, a generalized hybrid method combining the angular spectrum approach with the multipole expansion formalism in spherical coordinates is developed, which is applicable to any finite beam of arbitrary wavefront. The improved approach allows adequate computation of the resonance scattering, radiation force, and spin torque components on an object of arbitrary shape, located on or off the axis of the incident beam in space. Considering the illustrative example of a viscous fluid sphere submerged in a non-viscous liquid and illuminated by finite asymmetric beams such as the Airy and the Bessel vortex beam with fractional order, numerical computations for the scattering, radiation force, and torque components are performed with an emphasis on the distance from the source, the arbitrary location of the particle ,and the asymmetric nature of the incident field. Moreover, beamforming calculations are presented with supplementary animations for the pressure field distribution in space, with an emphasis on the intrinsic properties of the selected beams. The numerical predictions illustrate the scattering, radiation force, and spin torque properties depending on the beam parameters and the distance separating the sphere from the source. This study provides a generalized

  20. Laser beam shaping techniques

    Energy Technology Data Exchange (ETDEWEB)

    DICKEY,FRED M.; WEICHMAN,LOUIS S.; SHAGAM,RICHARD N.

    2000-03-16

    Industrial, military, medical, and research and development applications of lasers frequently require a beam with a specified irradiance distribution in some plane. A common requirement is a laser profile that is uniform over some cross-section. Such applications include laser/material processing, laser material interaction studies, fiber injection systems, optical data image processing, lithography, medical applications, and military applications. Laser beam shaping techniques can be divided into three areas: apertured beams, field mappers, and multi-aperture beam integrators. An uncertainty relation exists for laser beam shaping that puts constraints on system design. In this paper the authors review the basics of laser beam shaping and present applications and limitations of various techniques.

  1. Beam induced RF heating

    CERN Document Server

    Salvant, B; Arduini, G; Assmann, R; Baglin, V; Barnes, M J; Bartmann, W; Baudrenghien, P; Berrig, O; Bracco, C; Bravin, E; Bregliozzi, G; Bruce, R; Bertarelli, A; Carra, F; Cattenoz, G; Caspers, F; Claudet, S; Day, H; Garlasche, M; Gentini, L; Goddard, B; Grudiev, A; Henrist, B; Jones, R; Kononenko, O; Lanza, G; Lari, L; Mastoridis, T; Mertens, V; Métral, E; Mounet, N; Muller, J E; Nosych, A A; Nougaret, J L; Persichelli, S; Piguiet, A M; Redaelli, S; Roncarolo, F; Rumolo, G; Salvachua, B; Sapinski, M; Schmidt, R; Shaposhnikova, E; Tavian, L; Timmins, M; Uythoven, J; Vidal, A; Wenninger, J; Wollmann, D; Zerlauth, M

    2012-01-01

    After the 2011 run, actions were put in place during the 2011/2012 winter stop to limit beam induced radio frequency (RF) heating of LHC components. However, some components could not be changed during this short stop and continued to represent a limitation throughout 2012. In addition, the stored beam intensity increased in 2012 and the temperature of certain components became critical. In this contribution, the beam induced heating limitations for 2012 and the expected beam induced heating limitations for the restart after the Long Shutdown 1 (LS1) will be compiled. The expected consequences of running with 25 ns or 50 ns bunch spacing will be detailed, as well as the consequences of running with shorter bunch length. Finally, actions on hardware or beam parameters to monitor and mitigate the impact of beam induced heating to LHC operation after LS1 will be discussed.

  2. Craft Stick Beams

    Science.gov (United States)

    Karplus, Alan K.

    1996-01-01

    The objective of this exercise is to provide a phenomenological 'hands-on' experience that shows how geometry can affect the load carrying capacity of a material used in construction, how different materials have different failure characteristics, and how construction affects the performance of a composite material. This will be accomplished by building beams of a single material and composite beams of a mixture of materials (popsicle sticks, fiberboard sheets, and tongue depressors); testing these layered beams to determine how and where they fail; and based on the failure analysis, designing a layered beam that will fail in a predicted manner. The students will learn the effects of lamination, adhesion, and geometry in layered beam construction on beam strength and failure location.

  3. Theoretical models for recombination in expanding gas

    International Nuclear Information System (INIS)

    Avron, Y.; Kahane, S.

    1978-09-01

    In laser isotope separation of atomic uranium, one is confronted with the theoretical problem of estimating the concentration of thermally ionized uranium atoms. To investigate this problem theoretical models for recombination in an expanding gas and in the absence of local thermal equilibrium have been constructed. The expansion of the gas is described by soluble models of the hydrodynamic equation, and the recombination by rate equations. General results for the freezing effect for the suitable ranges of the gas parameters are obtained. The impossibility of thermal equilibrium in expanding two-component systems is proven

  4. Expanding your horizons in science and mathematics

    Science.gov (United States)

    1985-01-01

    Through the presentation of its Expanding Your Horizons in Science and Mathematics career education conferences for secondary school young women, the Math/Science Network continues its efforts to remove the educational, psychological, and cultural barriers which prevent women from entering math-and science-based careers. The Expanding Your Horizons conferences were presented on 77 college, university and high school campuses across the United States. This year, these unique one day conferences reached 15,500 students, 3,000 parents and educators, and involved 3,000 career women who volunteered their services as conference planners, workshop leaders, speakers, and role models.

  5. Beam Extraction and Transport

    CERN Document Server

    Kalvas, T.

    2013-12-16

    This chapter gives an introduction to low-energy beam transport systems, and discusses the typically used magnetostatic elements (solenoid, dipoles and quadrupoles) and electrostatic elements (einzel lens, dipoles and quadrupoles). The ion beam emittance, beam space-charge effects and the physics of ion source extraction are introduced. Typical computer codes for analysing and designing ion optical systems are mentioned, and the trajectory tracking method most often used for extraction simulations is described in more detail.

  6. Mechanical beam isolator

    International Nuclear Information System (INIS)

    Post, R.F.; Vann, C.S.

    1996-10-01

    Back-reflections from a target, lenses, etc. can gain energy passing backwards through a laser just like the main beam gains energy passing forwards. Unless something blocks these back-reflections early in their path, they can seriously damage the laser. A Mechanical Beam Isolator is a device that blocks back-reflections early, relatively inexpensively, and without introducing aberrations to the laser beam

  7. Cyclotron radiation beam control

    International Nuclear Information System (INIS)

    Dominke, P.

    1983-01-01

    This patent application describes an apparatus for attenuating a beam of particulate radiation comprising a series of modules, each module being constituted by a sphere having a passage, a cupola covering said sphere and a base supporting said sphere, and means for causing movement of the spheres for aligning said passages with an axis of a beam line and arranging said passages out of alignment so as to attenuate the beam. (author)

  8. Chilled beam application guidebook

    CERN Document Server

    Butler, David; Gräslund, Jonas; Hogeling, Jaap; Lund Kristiansen, Erik; Reinikanen, Mika; Svensson, Gunnar

    2007-01-01

    Chilled beam systems are primarily used for cooling and ventilation in spaces, which appreciate good indoor environmental quality and individual space control. Active chilled beams are connected to the ventilation ductwork, high temperature cold water, and when desired, low temperature hot water system. Primary air supply induces room air to be recirculated through the heat exchanger of the chilled beam. In order to cool or heat the room either cold or warm water is cycled through the heat exchanger.

  9. Who needs hyperon beams

    International Nuclear Information System (INIS)

    Lipkin, H.J.

    1976-01-01

    Hyperon beams can provide new interesting information about hadron structure and their strong, electromagnetic and weak interactions. The dependence of hadron interactions on strangeness and baryon number is not understood, and data from hyperon beams can provide new clues to paradoxes which arise in the interpretation of data from conventional beams. Examples of interesting data are total and differential cross sections, magnetic moments and values of Gsub(A)/Gsub(V) for weak semileptonic decays. (author)

  10. Measurement and tailoring of residual stress in expanded austenite on austenitic stainless steel

    DEFF Research Database (Denmark)

    Fernandes, Frederico Augusto Pires; Christiansen, Thomas Lundin; Winther, Grethe

    2017-01-01

    Expanded austenite on stainless steel with a high interstitial nitrogen content is characterized by elasto-plastic accommodation of the large composition-induced lattice expansion leading to huge compressive residual stress. The elasto-plastic accommodation as well as the (steep) concentration...... profile has implications for the measurement strategy to determine lattice strains and associated residual stresses with X-ray diffraction. Lattice strain measurements were performed on nitrided as well as subsequently de-nitrided expanded austenite on AISI 316L stainless steel, for various grazing...... incidence angles. It is demonstrated that keeping the information depth constant by choosing appropriate combinations of grazing incidence and tilt angle leads to reliable results for the 111 reflection, while the 200 reflection should be avoided. Further, it is shown for the first time that the residual...

  11. Instability of compensated beam-beam collisions

    International Nuclear Information System (INIS)

    Rosenzweig, J.B.; Autin, B.; Chen, Pisin.

    1989-01-01

    The beam-beam disruption phenomena in linear colliders are increasingly seen as a source of serious problems for these machines. A plasma compensation scheme, in which the motion of the plasma electrons in the presence of the colliding beams provides neutralizing charge and current densities, has been proposed and studied. But natural alternative to this scheme is to consider the overlapping of nearly identical high energy e + and e/sup /minus// bunches, and the collision of two such pairs - in other words, collision of two opposing relativistic positronium plasmas. It should be noticed that while the luminosity for all collisions is increased by a factor of four in this scheme, the event rate for e + e/sup /minus// collisions is only increased by a factor of two. The other factor of two corresponds to the addition of e + e + and e/sup /minus//e/sup /minus// collisions to the interaction point. This beam compensation scheme, which has been examined through computer simulation by Balakin and Solyak in the Soviet Union, promises full neutralization of beam charges and currents. These numerical investigations have shown that plasma instabilities exist in this nominally neutral system. Although the implementation of this idea seems technically daunting, the potential benefits (beamstrahlung and disruption suppression, relaxation of final focus system constraints) are such that we should consider the physics of these collisions further. In the remainder of this paper, we theoretically analyze the issues of stability and bunch parameter tolerances in this scheme. 11 refs

  12. Dual-beam CRT

    International Nuclear Information System (INIS)

    1975-01-01

    A dual-beam cathode-ray tube having a pair of electron guns and associated deflection means disposed side-by-side on each side of a central axis is described. The electron guns are parallel and the deflection means includes beam centering plates and angled horizontal deflection plates to direct the electron beams toward the central axis, precluding the need for a large-diameter tube neck in which the entire gun structures are angled. Bowing control plates are disposed adjacent to the beam centering plates to minimize trace bowing, and an intergun shield is disposed between the horizontal deflection plates to control and correct display pattern geometry distortion

  13. GANIL beam profile detectors

    International Nuclear Information System (INIS)

    Tribouillard, C.

    1997-01-01

    In the design phase of GANIL which started in 1977, one of the priorities of the project management was equipping the beamlines with a fast and efficient system for visualizing the beam position, thus making possible adjustment of the beam transport lines optics and facilitating beam control. The implantation of some thirty detectors was foreseen in the initial design. The assembly of installed detectors (around 190) proves the advantages of these detectors for displaying all the beams extracted from GANIL: transfer and transport lines, beam extracted from SISSI, very high intensity beam, secondary ion beams from the production target of the LISE and SPEG spectrometers, different SPIRAL project lines. All of these detectors are based on standard characteristics: - standard flange diameter (DN 160) with a standard booster for all the sensors; - identical analog electronics for all the detectors, with networking; - unique display system. The new micro-channel plate non-interceptive detectors (beam profile and ion packet lengths) make possible in-line control of the beam quality and accelerator stability. (author)

  14. ALFA beam halo

    CERN Document Server

    Komarek, Tomas

    2014-01-01

    This note serves as a final report about CERN Summer Student Programme 2014 project. The beam halo is an undesired phenomenon for physics analyses on particle accelerators. It surrounds the beam core and constitutes an important part of background for signal measurements on some detectors, eg. in the forward region. In this study, the data from the ALFA detector were used, specifically from the run 191373 ($\\beta^*=90\\unit{m}$) and the run 213268 ($\\beta^*=1\\unit{km}$). Using the ROOT framework, a software for beam halo events selection was created and beam halo properties were examined. In the run 213268, excessive beam halo is suspected to be the reason for multiple beam scrapings that occurred. A kinematic reconstruction of beam halo particles is attempted in order to understand beam halo properties in the interaction point. Some further simulations are employed to find constraints for beam halo particles in order to survive in the accelerator for a longer time/many revolutions. This work represents a st...

  15. Measurement system with high accuracy for laser beam quality.

    Science.gov (United States)

    Ke, Yi; Zeng, Ciling; Xie, Peiyuan; Jiang, Qingshan; Liang, Ke; Yang, Zhenyu; Zhao, Ming

    2015-05-20

    Presently, most of the laser beam quality measurement system collimates the optical path manually with low efficiency and low repeatability. To solve these problems, this paper proposed a new collimated method to improve the reliability and accuracy of the measurement results. The system accuracy controlled the position of the mirror to change laser beam propagation direction, which can realize the beam perpendicularly incident to the photosurface of camera. The experiment results show that the proposed system has good repeatability and the measuring deviation of M2 factor is less than 0.6%.

  16. Formation of focused laser beams with a hollow metal cone

    International Nuclear Information System (INIS)

    Wu, Pinghui; Pan, Quanjun; Wei, Kaihua; Wu, Bo; Jiang, Peipei; Li, Jia; Peng, Xuefeng

    2015-01-01

    A hollow metal cone is designed to focus a laser beam into a tiny highly localized beam spot. The finite difference time domain method has been introduced to investigate the beam focusing effect along the propagation direction. Without considering the laser–plasma nonlinear interaction, the numerical calculation results show that a focal spot with a full width at half maximum of ∼0.7λ at greatly enhanced intensity and a depth of focus of ∼3λ can be achieved. In addition, the influences of cone angle, cone tip size, metal materials, sidewall thickness and incident wavelength on the focusing properties are analyzed in detail. (letter)

  17. Simulation of Beam-Beam Background at CLIC

    CERN Document Server

    Sailer, Andre

    2010-01-01

    The dense beams used at CLIC to achieve a high luminosity will cause a large amount of background particles through beam-beam interactions. Generator level studies with GuineaPig and full detector simulation studies with an ILD based CLIC detector have been performed to evaluate the amount of beam-beam background hitting the vertex detector.

  18. Simulation of Beam-Beam Background at CLIC

    CERN Document Server

    Sailer, A

    2010-01-01

    The dense beams used at CLIC to achieve a high luminosity will cause a large amount of background particles through beam-beam interactions. Generator level studies with GUINEAPIG and full detector simulation studies with an ILD based CLIC detector have been performed to evaluate the amount of beam-beam back- ground hitting the vertex detector.

  19. Stable sheath formation in expanding magnetic field to divertor plate

    International Nuclear Information System (INIS)

    Tomita, Y.; Takayama, A.; Takamaru, H.; Sato, T.

    2001-01-01

    The stable sheath formation in expanding magnetic field to a divertor plate was studied theoretically by one-dimensional analysis. In fusion devices the magnetic field is expanding in the direction of the plate, i.e. the magnitude of magnetic field is decreasing to the plate. In this configuration ions are accelerated to the plate due to the gradient of the magnetic field strength, so called a mirror force. The bombardment of accelerated ions to the plate may cause several severe problems to fusion plasmas, for example, release of large amount of impurities from the diverter plate. Limited research efforts have been carried out describing magnetic field effects on various potential formation and particle and heat fluxes to the divertor plate. The plasma-wall interaction in an oblique to the plate but uniform magnetic field has been studied by means of 1D-PIC numerical simulation. This analysis shows the formation of a quasi-neutral magnetic pre-sheath preceding the electrostatic Debye sheath, which scales to the ion gyroradius at the sound speed and to the incidence angle of the magnetic field. Sato clarifies this magnetic pre-sheath is attributed to the ion polarisation drift by the two dimensional kinetic analysis. None of effects, however, of non-uniformity of the magnetic field has been taken into account on the stable electrostatic potential and sheath formation. In this paper, we consider a collisionless sheath model between an infinite metal plate and a quasi-neutral plasma in the expanding magnetic field to the plate. One dimensional kinetic analysis leads that a condition for flow velocity of ions at a plasma-sheath boundary is more restricted than that of the uniform magnetic field, which should be larger than the ion sound speed. The difference, however, between both cases is an order of the Debye length to a plasma radius, which is negligible small. The requirement for the ion flow velocity inside the plasma is obtained from the condition of the quasi

  20. Final design of kaon beam K2 at KEK

    International Nuclear Information System (INIS)

    Kurokawa, Shin-ichi; Yamamoto, Akira.

    1977-09-01

    Final design of the 2.3 GeV/c kaon beam K2 is given. The K2 beam starts from the production target in slow extracted beam. Momentum range is 1 GeV/c through 2.3 GeV/c. Nominal total beam length is 27.9 m and solid-angle momentum acceptance is 6.25 msr%ΔP/P. Using a platinum target of diameter 3 mm and length 6 cm, 2.0 GeV/c beam fluxes of 1.0 x 10 6 K + and 5.2 x 10 5 K - per 10 12 13 GeV/c incident protons are expected at the final focus. (auth.)

  1. Analysis of inborn errors of metabolism: disease spectrum for expanded newborn screening in Hong Kong.

    Science.gov (United States)

    Lee, Han-Chih Hencher; Mak, Chloe Miu; Lam, Ching-Wan; Yuen, Yuet-Ping; Chan, Angel On-Kei; Shek, Chi-Chung; Siu, Tak-Shing; Lai, Chi-Kong; Ching, Chor-Kwan; Siu, Wai-Kwan; Chen, Sammy Pak-Lam; Law, Chun-Yiu; Tai, Hok-Leung Morris; Tam, Sidney; Chan, Albert Yan-Wo

    2011-04-01

    Data of classical inborn errors of metabolism (IEM) of amino acids, organic acids and fatty acid oxidation are largely lacking in Hong Kong, where mass spectrometry-based expanded newborn screening for IEM has not been initiated. The current study aimed to evaluate the approximate incidence, spectrum and other characteristics of classical IEM in Hong Kong, which would be important in developing an expanded newborn screening program for the local area. The laboratory records of plasma amino acids, plasma acylcarnitines and urine organic acids analyses from year 2005 to 2009 inclusive in three regional chemical pathology laboratories providing biochemical and genetic diagnostic services for IEM were retrospectively reviewed. Among the cohort, 43 patients were diagnosed of IEM, including 30 cases (69%) of amino acidemias (predominantly citrin deficiency, hyperphenylalaninemia due to 6-pyruvoyl-tetrahydropterin synthase deficiency and tyrosinemia type I), 5 cases (12%) of organic acidemias (predominantly holocarboxylase synthetase deficiency) and 8 cases (19%) of fatty acid oxidation defects (predominantly carnitine-acylcarnitine translocase deficiency). The incidence of classical IEM in Hong Kong was roughly estimated to be at least 1 case per 4122 lives births, or 0.243 cases per 1000 live births. This incidence is similar to those reported worldwide, including the mainland of China. The estimated incidence of hyperphenylalaninemia was 1 in 29 542 live births. Our data indicate that it is indisputable for the introduction of expanded newborn screening program in Hong Kong. Since Hong Kong is a metropolitan city, a comprehensive expanded newborn screening program and referral system should be available to serve the neonates born in the area.

  2. Equilibrium-Based Nonhomogeneous Anisotropic Beam Element

    DEFF Research Database (Denmark)

    Krenk, Steen; Couturier, Philippe

    2017-01-01

    The stiffness matrix and the nodal forces associated with distributed loads are obtained for a nonhomogeneous anisotropic elastic beam element by the use of complementary energy. The element flexibility matrix is obtained by integrating the complementary-energy density corresponding to six beam...... equilibrium states, and then inverted and expanded to provide the element-stiffness matrix. Distributed element loads are represented via corresponding internal-force distributions in local equilibrium with the loads. The element formulation does not depend on assumed shape functions and can, in principle......, include any variation of cross-sectional properties and load variation, provided that these are integrated with sufficient accuracy in the process. The ability to represent variable cross-sectional properties, coupling from anisotropic materials, and distributed element loads is illustrated by numerical...

  3. Field flattening in superconducting beam transport magnets

    International Nuclear Information System (INIS)

    Morgan, G.H.

    1994-01-01

    Dipoles in which the beam traverses the midplane well away from tie magnet axis may benefit from flattening of the vertical field on the midplane. A procedure is described for doing so, making use of Chebyshev polynomials. In the case of the large aperture ''DX'' magnets located immediately on each side of the six intersection regions of the Relativistic Heavy Ion Powder (RHIC), a comparison is made of the field of coils optimized in this way and of coils optimized in the more common way by minimizing the leading coefficients of the Fourier expansion about the magnet axis. The comparison is of the integrated Fourier coefficients of the field expanded locally along the beam trajectory

  4. Constipation and Incident CKD.

    Science.gov (United States)

    Sumida, Keiichi; Molnar, Miklos Z; Potukuchi, Praveen K; Thomas, Fridtjof; Lu, Jun Ling; Matsushita, Kunihiro; Yamagata, Kunihiro; Kalantar-Zadeh, Kamyar; Kovesdy, Csaba P

    2017-04-01

    Constipation is one of the most prevalent conditions in primary care settings and increases the risk of cardiovascular disease, potentially through processes mediated by altered gut microbiota. However, little is known about the association of constipation with CKD. In a nationwide cohort of 3,504,732 United States veterans with an eGFR ≥60 ml/min per 1.73 m 2 , we examined the association of constipation status and severity (absent, mild, or moderate/severe), defined using diagnostic codes and laxative use, with incident CKD, incident ESRD, and change in eGFR in Cox models (for time-to-event analyses) and multinomial logistic regression models (for change in eGFR). Among patients, the mean (SD) age was 60.0 (14.1) years old; 93.2% of patients were men, and 24.7% were diabetic. After multivariable adjustments, compared with patients without constipation, patients with constipation had higher incidence rates of CKD (hazard ratio, 1.13; 95% confidence interval [95% CI], 1.11 to 1.14) and ESRD (hazard ratio, 1.09; 95% CI, 1.01 to 1.18) and faster eGFR decline (multinomial odds ratios for eGFR slope constipation associated with an incrementally higher risk for each renal outcome. In conclusion, constipation status and severity associate with higher risk of incident CKD and ESRD and with progressive eGFR decline, independent of known risk factors. Further studies should elucidate the underlying mechanisms. Copyright © 2017 by the American Society of Nephrology.

  5. Cancer incidence among firefighters

    DEFF Research Database (Denmark)

    Pukkala, Eero; Martinsen, Jan Ivar; Weiderpass, Elisabete

    2014-01-01

    .51), adenocarcinoma of the lung (SIR=1.90, 95% CI 1.34 to 2.62), and mesothelioma (SIR=2.59, 95% CI 1.24 to 4.77). By contrast with earlier studies, the incidence of testicular cancer was decreased (SIR=0.51, 95% CI 0.23 to 0.98). CONCLUSIONS: Some of these associations have been observed previously, and potential...

  6. Circle diffeomorphisms forced by expanding circle maps

    NARCIS (Netherlands)

    Homburg, A.J.

    2012-01-01

    We discuss the dynamics of skew product maps defined by circle diffeomorphisms forced by expanding circle maps. We construct an open class of such systems that are robustly topologically mixing and for which almost all points in the same fiber converge under iteration. This property follows from the

  7. Strengthening youth friendly health services through expanding ...

    African Journals Online (AJOL)

    Strengthening youth friendly health services through expanding method choice to include long-acting reversible contraceptives for Ethiopian youth. ... Odds of adopting LARCs at pre-intervention (0.70); rose to 1.30 for the post-intervention phase (p-value <0.0001); comparing intervention to non-intervention study arms.

  8. Expanding economic opportunities in protracted displacement

    Directory of Open Access Journals (Sweden)

    Miki Takahashi

    2018-02-01

    Full Text Available Welcome progress has been made towards realising commitments made by international donors and host country governments to expand economic opportunities for Syrian refugees and host communities in neighbouring countries. However targets and commitments also bring new challenges, and evidence must underpin new policies.

  9. Expanded austenite; crystallography and residual stress

    DEFF Research Database (Denmark)

    Christiansen, Thomas; Hummelshøj, Thomas Strabo; Somers, Marcel A. J.

    2009-01-01

    The identity of expanded austenite as developing during low temperature nitriding and/or carburizing of austenitic stainless steel has been under debate since the very first observation of this phase. In the present article recent results obtained with i) homogeneous samples of various uniform co...

  10. Expanded austenite, crystallography and residual stress

    DEFF Research Database (Denmark)

    Christiansen, Thomas; Hummelshøj, Thomas Strabo; Somers, Marcel A. J.

    2010-01-01

    The identity of expanded austenite as developing during low temperature nitriding and/or carburising of austenitic stainless steel has been under debate since the very first observation of this phase. In the present article, recent results obtained with (a) homogeneous samples of various uniform ...

  11. Expanding Arts Education in a Digital Age

    Science.gov (United States)

    Choi, Haeryun; Piro, Joseph M.

    2009-01-01

    This article proposes a way to expand the study of arts education within new contexts of technology and globalization. Drawing upon theories that have informed arts and aesthetic education in the past, the authors suggest new applications for these ideas to ensure that arts education sustains its significance in twenty-first-century society. The…

  12. FDA Expands Abiraterone Approval for Prostate Cancer

    Science.gov (United States)

    The FDA has expanded the approval of abiraterone (Zytiga) to treat men with metastatic prostate cancer. The agency approved abiraterone, in combination with prednisone, for men whose cancer that is responsive to hormone-blocking treatments (also known as castration-sensitive) and is at high risk of progressing.

  13. Sulfonated graphenes catalyzed synthesis of expanded porphyrins ...

    Indian Academy of Sciences (India)

    Sulfonated graphene; expanded porphyrins; heterogeneous catalysis; solid acid; non-covalent interaction. 1. Introduction. Graphene, an important allotropic member of carbon, has received much attention owing to its interest- ing properties in material science with wide range of applications in energy devices, electronics, ...

  14. Expanding the applicability of Heallth Technology Assessments

    DEFF Research Database (Denmark)

    Draborg, Eva; Hansen, Helle Ploug

    2012-01-01

    The objective of the presentation is to expand the foundations of input into policy decision making relying on health technology assessments (HTA). HTAs are primarily based on systematic reviews (SR) and thereby mostly on randomized controlled trials (RCT). RCTs can be distinguished on a continuu...

  15. Hubble, Hubble's Law and the Expanding Universe

    Indian Academy of Sciences (India)

    Srimath

    Hubble, Hubble's Law and the Expanding Universe. J S Bagla. Jasjeet Bagla works at the. Harish-Chandra Research. Institute, Allahabad. His research is mainly on cosmology and he is interested in all areas of physics. Keywords. Cosmology, Big Bang, expan- sion of universe. H ubble's nam e is associated closely w ith ...

  16. Hubble, Hubble's Law and the Expanding Universe

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 14; Issue 3. Hubble, Hubble's Law and the Expanding Universe. J S Bagla. General Article Volume 14 Issue 3 March 2009 pp 216-225. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/014/03/0216-0225 ...

  17. Women Engineering Faculty: Expanding the Pipeline

    Science.gov (United States)

    Greni, Nadene Deiterman

    2006-01-01

    The purpose for this case study was to explore the features of undergraduate engineering departmental and college support that influenced the persistence of women students. Women engineering faculty members were among the participants at three Land Grant universities in the Midwest. The data revealed the theme, Expanding the Pipeline, and…

  18. CLASSICS WHY THE UNIVERSE IS EXPANDING

    Indian Academy of Sciences (India)

    accuracy, to the product of the particle velocity u and the time t: r = ut. But this is nothing other than Hubble's law of the expanding Universe. Rewriting the formula as u = (1/t)r and putting 1/t = H (Hubble's constant), we obtain u = Hr. So, the two principal similarities of a chemical explosion and the “Big Bang” are: cooling.

  19. Sulfonated graphenes catalyzed synthesis of expanded porphyrins ...

    Indian Academy of Sciences (India)

    A newer synthesis of sulfonic acid functionalized graphenes have been developed, which have been characterized, examined as heterogeneous solid acid carbocatalyst in the synthesis of selected expanded porphyrins in different reaction conditions. This environment-friendly catalyst avoids the use of toxic catalysts and ...

  20. Heptaphyrins: Expanded porphyrins with seven heterocyclic rings

    Indian Academy of Sciences (India)

    Unknown

    -mail: tkc@iitk.ac.in ... The syntheses of expanded porphyrins continue to attract the attention of chemists because of their diverse .... The aromatic nature of the heptaphyrins, 7–9, was proved by various analytical methods. The Soret-like ...

  1. Heptaphyrins: Expanded porphyrins with seven heterocyclic rings

    Indian Academy of Sciences (India)

    Unknown

    ring inversion. 1. Introduction. The syntheses of expanded porphyrins continue to attract the attention of chemists because of their diverse biological applications such as: anion receptors, photosensitizing agents, MRI contrast agents1 etc. They are also of interest, theoretically, to study the fundamental property of aromaticity ...

  2. Technical Note: Effect of Incorporating Expanded Polystyrene ...

    African Journals Online (AJOL)

    Workability which is an important property of concrete, aects the rate of placement and the degree of compaction of concrete. Inadequate compaction leads to reduction in both strength and durability of concrete. In this research work, the effect of incorporation of expanded polystyrene aggregate granules in concrete was ...

  3. Hubble, Hubble's Law and the Expanding Universe

    Indian Academy of Sciences (India)

    Srimath

    Cosmology, Big Bang, expan- sion of universe. H ubble's nam e is associated closely w ith the idea of an expanding universe as he discovered the relation between the recession velocity and the distances of galaxies. H ubble also did a lot of pioneering w ork on the distribution of galaxies in the universe. In this article we ...

  4. Properties of extruded expandable breadfruit products

    Science.gov (United States)

    Dried breadfruit was extruded with a twin screw extruder to develop a value-added expanded fruit product. This research studied the effects of barrel temperature (120-160°C), moisture content (13-25%), feeding rate (13-25 kg/h) and screw speed (115-175rpm) on physicochemical properties (bulk densit...

  5. Expanding Your Horizons Conference in Geneva

    CERN Multimedia

    Chromek-Burckhart, Doris

    2011-01-01

    CERN and its experiments participated in Expanding Your Horizons (EYH) in Science and Mathematics conference in Geneva on 12th November. EYH nurture girls' interest in science and math courses to encourage them to consider careers in science, technology, engineering, and math.

  6. Expanded Core Curriculum: 12 Years Later

    Science.gov (United States)

    Lohmeier, Keri; Blankenship, Karen; Hatlen, Phil

    2009-01-01

    This study investigated changes in teachers' and parents' understanding and implementation of or philosophy on the implementation of the content areas of the expanded core curriculum for students who are visually impaired. The results demonstrated some changes since the original survey results were reported in 1998 and a discrepancy between the…

  7. Heat expanded starch-based compositions.

    Science.gov (United States)

    Glenn, Gregory M; Klamczynski, Artur K; Holtman, Kevin M; Shey, Justin; Chiou, Bor-Sen; Berrios, Jose; Wood, Delilah; Orts, William J; Imam, Syed H

    2007-05-16

    A heat expansion process similar to that used for expanded bead polystyrene was used to expand starch-based compositions. Foam beads made by solvent extraction had the appearance of polystyrene beads but did not expand when heated due to an open-cell structure. Nonporous beads, pellets, or particles were made by extrusion or by drying and milling cooked starch slurries. The samples expanded into a low-density foam by heating 190-210 degrees C for more than 20 s at ambient pressures. Formulations containing starch (50-85%), sorbitol (5-15%), glycerol (4-12%), ethylene vinyl alcohol (EVAL, 5-15%), and water (10-20%) were studied. The bulk density was negatively correlated to sorbitol, glycerol, and water content. Increasing the EVAL content increased the bulk density, especially at concentrations higher than 15%. Poly(vinyl alcohol) (PVAL) increased the bulk density more than EVAL. The bulk density was lowest in samples made of wheat and potato starch as compared to corn starch. The expansion temperature for the starch pellets decreased more than 20 degrees C as the moisture content was increased from 10 to 25%. The addition of EVAL in the formulations decreased the equilibrium moisture content of the foam and reduced the water absorption during a 1 h soaking period.

  8. Exploiting cellophane birefringence to generate radially and azimuthally polarised vector beams

    International Nuclear Information System (INIS)

    Kalwe, Johnston; Ominde, Calvine; Rurimo, Geoffrey; Neugebauer, Martin; Leuchs, Gerd; Banzer, Peter

    2015-01-01

    We exploit the birefringence of cellophane to convert a linearly polarised Gaussian beam into either a radially or azimuthally polarised beam. For that, we fabricated a low-cost polarisation mask consisting of four segments of cellophane. The fast axis of each segment is oriented appropriately in order to rotate the polarisation of the incident linearly polarised beam as desired. To ensure the correct operation of the polarisation mask, we tested the polarisation state of the generated beam by measuring the spatial distribution of the Stokes parameters. Such a device is very cost efficient and allows for the generation of cylindrical vector beams of high quality. (paper)

  9. Spatial Distribution of Black Bear Incident Reports in Michigan.

    Directory of Open Access Journals (Sweden)

    Jamie E McFadden-Hiller

    Full Text Available Interactions between humans and carnivores have existed for centuries due to competition for food and space. American black bears are increasing in abundance and populations are expanding geographically in many portions of its range, including areas that are also increasing in human density, often resulting in associated increases in human-bear conflict (hereafter, bear incidents. We used public reports of bear incidents in Michigan, USA, from 2003-2011 to assess the relative contributions of ecological and anthropogenic variables in explaining the spatial distribution of bear incidents and estimated the potential risk of bear incidents. We used weighted Normalized Difference Vegetation Index mean as an index of primary productivity, region (i.e., Upper Peninsula or Lower Peninsula, primary and secondary road densities, and percentage land cover type within 6.5-km2 circular buffers around bear incidents and random points. We developed 22 a priori models and used generalized linear models and Akaike's Information Criterion (AIC to rank models. The global model was the best compromise between model complexity and model fit (w = 0.99, with a ΔAIC 8.99 units from the second best performing model. We found that as deciduous forest cover increased, the probability of bear incident occurrence increased. Among the measured anthropogenic variables, cultivated crops and primary roads were the most important in our AIC-best model and were both positively related to the probability of bear incident occurrence. The spatial distribution of relative bear incident risk varied markedly throughout Michigan. Forest cover fragmented with agriculture and other anthropogenic activities presents an environment that likely facilitates bear incidents. Our map can help wildlife managers identify areas of bear incident occurrence, which in turn can be used to help develop strategies aimed at reducing incidents. Researchers and wildlife managers can use similar mapping

  10. Spatial Distribution of Black Bear Incident Reports in Michigan.

    Science.gov (United States)

    McFadden-Hiller, Jamie E; Beyer, Dean E; Belant, Jerrold L

    2016-01-01

    Interactions between humans and carnivores have existed for centuries due to competition for food and space. American black bears are increasing in abundance and populations are expanding geographically in many portions of its range, including areas that are also increasing in human density, often resulting in associated increases in human-bear conflict (hereafter, bear incidents). We used public reports of bear incidents in Michigan, USA, from 2003-2011 to assess the relative contributions of ecological and anthropogenic variables in explaining the spatial distribution of bear incidents and estimated the potential risk of bear incidents. We used weighted Normalized Difference Vegetation Index mean as an index of primary productivity, region (i.e., Upper Peninsula or Lower Peninsula), primary and secondary road densities, and percentage land cover type within 6.5-km2 circular buffers around bear incidents and random points. We developed 22 a priori models and used generalized linear models and Akaike's Information Criterion (AIC) to rank models. The global model was the best compromise between model complexity and model fit (w = 0.99), with a ΔAIC 8.99 units from the second best performing model. We found that as deciduous forest cover increased, the probability of bear incident occurrence increased. Among the measured anthropogenic variables, cultivated crops and primary roads were the most important in our AIC-best model and were both positively related to the probability of bear incident occurrence. The spatial distribution of relative bear incident risk varied markedly throughout Michigan. Forest cover fragmented with agriculture and other anthropogenic activities presents an environment that likely facilitates bear incidents. Our map can help wildlife managers identify areas of bear incident occurrence, which in turn can be used to help develop strategies aimed at reducing incidents. Researchers and wildlife managers can use similar mapping techniques to

  11. Cancer incidence among waiters

    DEFF Research Database (Denmark)

    Reijula, Jere; Kjaerheim, Kristina; Lynge, Elsebeth

    2015-01-01

    AIMS: To study cancer risk patterns among waiters in the Nordic countries. METHODS: We identified a cohort of 16,134 male and 81,838 female waiters from Denmark, Finland, Iceland, Norway and Sweden. During the follow-up period from 1961 to 2005, we found that 19,388 incident cancer cases were...... diagnosed. Standardised incidence ratio (SIR) was defined as the observed number of cancer cases divided by the expected number, based on national age, time period and gender-specific cancer incidence rates in the general population. RESULTS: The SIR of all cancers in waiters, in the five countries combined......, was 1.46 (95% CI 1.41-1.51) in men and 1.09 (1.07-1.11) in women. In male waiters, the SIR decreased from 1.79 (1.63-1.96) in 1961-1975, to 1.33 (1.26-1.40) in 1991-2005, but remained stable among women. The SIR among male waiters was highest for cancers in the pharynx (6.11; 95% CI 5.02-7.37), oral...

  12. Contaminated Mexican steel incident

    International Nuclear Information System (INIS)

    1985-01-01

    This report documents the circumstances contributing to the inadvertent melting of cobalt 60 (Co-60) contaminated scrap metal in two Mexican steel foundries and the subsequent distribution of contaminated steel products into the United States. The report addresses mainly those actions taken by US Federal and state agencies to protect the US population from radiation risks associated with the incident. Mexico had much more serious radiation exposure and contamination problems to manage. The United States Government maintained a standing offer to provide technical and medical assistance to the Mexican Government. The report covers the tracing of the source to its origin, response actions to recover radioactive steel in the United States, and return of the contaminated materials to Mexico. The incident resulted in significant radiation exposures within Mexico, but no known significant exposure within the United States. Response to the incident required the combined efforts of the Nuclear Regulatory Commission (NRC), Department of Energy, Department of Transportation, Department of State, and US Customs Service (Department of Treasury) personnel at the Federal level and representatives of all 50 State Radiation Control Programs and, in some instances, local and county government personnel. The response also required a diplomatic interface with the Mexican Government and cooperation of numerous commercial establishments and members of the general public. The report describes the factual information associated with the event and may serve as information for subsequent recommendations and actions by the NRC. 8 figures

  13. Examination of the CLIC drive beam pipe design for thermal distortion caused by distributed beam loss

    CERN Document Server

    Johnson, C D

    1997-01-01

    Beam transport programs are widely used to estimate the distribution of power deposited in accelerator structures by particle beams, either intentionally as for targets or beam dumps or accidentally owing to beam loss incidents. While this is usually adequate for considerations of radiation safety, it does not reveal the expected temperature rise and its effect on structural integrity. To find this, thermal diffusion must be taken into account, requiring another step in the analysis. The method that has been proposed is to use the output of a transport program, perhaps modified, as input for a finite element analysis program that can solve the thermal diffusion equation. At CERN, the design of the CLIC drive beam pipe has been treated in this fashion. The power distribution produced in the walls by a distributed beam loss was found using the electron gamma shower code EGS4. The distribution of power density was then used to form the input for the finite element analysis program ANSYS, which was able to find t...

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

    Science.gov (United States)

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

    2015-10-01

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

  15. Refrigeration generation using expander-generator units

    Science.gov (United States)

    Klimenko, A. V.; Agababov, V. S.; Koryagin, A. V.; Baidakova, Yu. O.

    2016-05-01

    The problems of using the expander-generator unit (EGU) to generate refrigeration, along with electricity were considered. It is shown that, on the level of the temperatures of refrigeration flows using the EGU, one can provide the refrigeration supply of the different consumers: ventilation and air conditioning plants and industrial refrigerators and freezers. The analysis of influence of process parameters on the cooling power of the EGU, which depends on the parameters of the gas expansion process in the expander and temperatures of cooled environment, was carried out. The schematic diagram of refrigeration generation plant based on EGU is presented. The features and advantages of EGU to generate refrigeration compared with thermotransformer of steam compressive and absorption types were shown, namely: there is no need to use the energy generated by burning fuel to operate the EGU; beneficial use of the heat delivered to gas from the flow being cooled in equipment operating on gas; energy production along with refrigeration generation, which makes it possible to create, using EGU, the trigeneration plants without using the energy power equipment. It is shown that the level of the temperatures of refrigeration flows, which can be obtained by using the EGU on existing technological decompression stations of the transported gas, allows providing the refrigeration supply of various consumers. The information that the refrigeration capacity of an expander-generator unit not only depends on the parameters of the process of expansion of gas flowing in the expander (flow rate, temperatures and pressures at the inlet and outlet) but it is also determined by the temperature needed for a consumer and the initial temperature of the flow of the refrigeration-carrier being cooled. The conclusion was made that the expander-generator units can be used to create trigeneration plants both at major power plants and at small energy.

  16. Adjustable hollow-cone output x-ray beam from an ellipsoidal monocapillary with a pinhole and a beam stop.

    Science.gov (United States)

    Sun, Xue-Peng; Liu, Zhi-Gou; Yi, Long-Tao; Sun, Wei-Yun; Li, Fang-Zou; Jiang, Bo-Wen; Ma, Yong-Zhong; Sun, Tian-Xi

    2015-12-10

    A combined shading system (CSS) consisting of a beam stop and a pinhole is proposed to be used between an ellipsoidal monocapillary (EM) and a conventional laboratory x-ray source to obtain an adjustable hollow-cone output beam for different experiments with no need for changing the EM. The CSS can change the incident x-ray beam on the EM by adjusting the position of the beam stop and the pinhole, with the corresponding change of the output beam of the EM. In this study, the adjustable hollow-cone output x-ray beam of an 80-mm-long EM with a CSS was studied in detail with a laboratory Cu x-ray generator with a focal spot diameter of 50 μm. The adjustable range of the focal spot size of the EM was from 8.6 to 58.7 μm. The adjustable range of the gain of the focal spot of the EM was from 0 to 1350. The beam divergence of the hollow-cone output beam of the EM ranged from 6 to 16.75 mrad. The illumination angle of the hollow-cone output beam of the EM ranged from 0 to 5.95 mrad. In addition, the potential application of the proposed adjusting method in testing the performance of the EM is briefly discussed.

  17. Electron beam diagnostics study

    International Nuclear Information System (INIS)

    Garganne, P.

    1989-08-01

    This paper summarizes the results of a study on beam diagnostics, using carbon wire scanners and optical transition radiation (DTR) monitors. The main consideration consists in the material selection, taking their thermal properties and their effect on the beam into account [fr

  18. Atomic Ferris wheel beams

    OpenAIRE

    Lembessis, Vasileios E.

    2017-01-01

    We study the generation of atom vortex beams in the case where an atomic wave-packet, moving in free space, is diffracted from a properly tailored light mask with a spiral transverse profile. We show how such a diffraction scheme could lead to the production of an atomic Ferris wheel beam.

  19. Atomic Ferris wheel beams

    Science.gov (United States)

    Lembessis, Vasileios E.

    2017-07-01

    We study the generation of atom vortex beams in the case where a Bose-Einstein condensate, released from a trap and moving in free space, is diffracted from a properly tailored light mask with a spiral transverse profile. We show how such a diffraction scheme could lead to the production of an atomic Ferris wheel beam.

  20. Ionization beam scanner

    CERN Multimedia

    CERN PhotoLab

    1973-01-01

    Inner structure of an ionization beam scanner, a rather intricate piece of apparatus which permits one to measure the density distribution of the proton beam passing through it. On the outside of the tank wall there is the coil for the longitudinal magnetic field, on the inside, one can see the arrangement of electrodes creating a highly homogeneous transverse electric field.

  1. Electron beam transport

    International Nuclear Information System (INIS)

    Rudjak, Yu.V.; Vladyko, V.B.

    1993-01-01

    The electron beam transport in ion channel has been investigated. The influence of the external longitudinal magnetic field and self beam magnetic field on the charge neutralization process was defined. Beam head erosion under channel is curved or the availability of transverse external magnetic field was numerically simulated. The numerical investigation of the ion-hose instability was performed. The conditions, when as a result of ion-hose instability development may be coming out of the channel by beam tail, were founded. It was shown, that supplementary creation of plasma by electron beam and ions did not lead to the reduction of ion-hose instability. Sufficient slowing down of ion-hose instability development could be achieved if betatron length increased to impulse tail. In the case of a weak initial nonsymmetrical perturbation, sausage instability was investigated. Numerical simulation showed that this instability could lead to beam radius increasing in order. The electron beam guiding by low conductive plasma channel was considered. The attractive force of beam to this channel under nonsymmetrical injection was defined analytically

  2. Durnin-Whitney beams

    Science.gov (United States)

    de Jesús Cabrera-Rosas, Omar; Espíndola-Ramos, Ernesto; Alejandro Juárez-Reyes, Salvador; Julián-Macías, Israel; Ortega-Vidals, Paula; Rickenstorff-Parrao, Carolina; Silva-Ortigoza, Gilberto; Silva-Ortigoza, Ramón; Sosa-Sánchez, Citlalli Teresa

    2017-05-01

    The aim of the present work is to define a Durnin-Whitney beam as a nondiffracting beam such that its associated caustic locally only has singularities of the fold and cusp types. Since the caustic is structurally stable then the intensity pattern of this beam is also stable and this property is what makes its definition and its theoretical and experimental study worthwhile. These properties are important in applications such as uniform optical drilling in waveguides and communications through weak turbulent atmosphere. We find that in accordance with Whitney's theorem on the stability of maps from a two-dimensional manifold to a two-dimensional manifold the phase g({{Φ }}), of the complex function A({{Φ }}) characterizing the beam, locally is given by g({{Φ }})=a{{Φ }} for a fold and g({{Φ }})=b{{{Φ }}}2 for a cusp. This result implies that the Bessel beam of order zero is not stable and that any other Bessel beam is stable because locally it has a caustic of fold type. Finally, we present an example of a Durnin-Whitney beam given by g({{Φ }})=m{{Φ }}+b{{{Φ }}}2, which is a natural generalization of the Bessel beam of order m with a singularity of cusp ridge type.

  3. Dosimetry of pion beams

    International Nuclear Information System (INIS)

    Dicello, J.F.

    1975-01-01

    Negative pion beams are probably the most esoteric and most complicated type of radiation which has been suggested for use in clinical radiotherapy. Because of the limited availability of pion beams in the past, even to nuclear physicists, there exist relatively fewer basic data for this modality. Pion dosimetry is discussed

  4. Beaming teaching application

    DEFF Research Database (Denmark)

    Markovic, Milos; Madsen, Esben; Olesen, Søren Krarup

    2012-01-01

    BEAMING is a telepresence research project aiming at providing a multimodal interaction between two or more participants located at distant locations. One of the BEAMING applications allows a distant teacher to give a xylophone playing lecture to the students. Therefore, rendering of the xylophon...

  5. Beam director design report

    International Nuclear Information System (INIS)

    Younger, F.C.

    1986-08-01

    A design and fabrication effort for a beam director is documented. The conceptual design provides for the beam to pass first through a bending and focusing system (or ''achromat''), through a second achromat, through an air-to-vacuum interface (the ''beam window''), and finally through the vernier steering system. Following an initial concept study for a beam director, a prototype permanent magnet 30 0 beam-bending achromat and prototype vernier steering magnet were designed and built. In volume II, copies are included of the funding instruments, requests for quotations, purchase orders, a complete set of as-built drawings, magnetic measurement reports, the concept design report, and the final report on the design and fabrication project

  6. Vortices in Gaussian beams

    CSIR Research Space (South Africa)

    Roux, FS

    2009-01-01

    Full Text Available , t0)} = P(du, dv) {FR{g(u, v, t0)}} Replacement: u→ du = t− t0 i2 ∂ ∂u′ v → dv = t− t0 i2 ∂ ∂v′ CSIR National Laser Centre – p.13/30 Differentiation i.s.o integration Evaluate the integral over the Gaussian beam (once and for all). Then, instead... . Gaussian beams with vortex dipoles CSIR National Laser Centre – p.2/30 Gaussian beam notation Gaussian beam in normalised coordinates: g(u, v, t) = exp ( −u 2 + v2 1− it ) u = xω0 v = yω0 t = zρ ρ = piω20 λ ω0 — 1/e2 beam waist radius; ρ— Rayleigh range ω ω...

  7. Bunched beam diagnostics

    International Nuclear Information System (INIS)

    Siemann, R.H.

    1989-01-01

    There is a remarkable diversity in the field of accelerator physics. Look at the proceedings of any conference. Papers range from Hamiltonian dynamics to the latest improvements of performance in accelerator X to the engineering of specialized equipment. Beam diagnostics is somewhere in the middle of this. Diagnostic instruments make the connection between theories and observations, and the capabilities of these instruments influence strongly our ability to improve performance. The gave a series of lectures in 1987 on the general topic of Principles of Beam Observation. The emphasis was on frequency domain analysis of beam generated signals in storage rings, and that is the subject of this paper. The goal is to connect spectrum analyzer observations to what the beam is doing. In addition, understanding beam spectra is essential for understanding coherent effects and instabilities in storage rings, and this is discussed extensively. 23 figures, 4 tables

  8. Atom beam source

    International Nuclear Information System (INIS)

    Franks, J.

    1984-01-01

    Ion beam V etching may give rise to undesirable effects such as uneven erosion and ion migration in dielectrics, even when the surface is neutralized by electron flooding. The effects appear due to a remaining charge imbalance on a microscopic scale, which is absent when bombarding with an uncharged beam. Saddle field sources provide a convenient means of producing energetic neutral beams of inert and reactive gases (which may be dissociated into radicals). The construction and characteristics of the sources are described and a mechanism of internal neutralization proposed. Evidence is given that uncharged beams introduce less damage than equivalent ion beams. Disruptive effects may be initiated by charge accumulation or possibly by neutralization processes which occur when ions closely approach the target surface. (author)

  9. Ion beam monitoring

    International Nuclear Information System (INIS)

    McKinney, C.R.

    1980-01-01

    An ion beam analyzer is specified, having an ion source for generating ions of a sample to be analyzed, means for extracting the sample ions, means for focusing the sample ions into a beam, separation means positioned along the ion beam for selectively deflecting species of ions, and means for detecting the selected species of ions. According to the specification, the analyzer further comprises (a) means for disabling at least a portion of the separation means, such that the ion beam from the source remains undeflected; (b) means located along the path of the undeflected ion beam for sensing the sample ions; and (c) enabling means responsive to the sensing means for automatically re-enabling the separation means when the sample ions reach a predetermined intensity level. (author)

  10. Beam director design report

    Energy Technology Data Exchange (ETDEWEB)

    Younger, F.C.

    1986-08-01

    A design and fabrication effort for a beam director is documented. The conceptual design provides for the beam to pass first through a bending and focusing system (or ''achromat''), through a second achromat, through an air-to-vacuum interface (the ''beam window''), and finally through the vernier steering system. Following an initial concept study for a beam director, a prototype permanent magnet 30/sup 0/ beam-bending achromat and prototype vernier steering magnet were designed and built. In volume II, copies are included of the funding instruments, requests for quotations, purchase orders, a complete set of as-built drawings, magnetic measurement reports, the concept design report, and the final report on the design and fabrication project. (LEW)

  11. Minimally invasive transforaminal lumbar interbody fusion with expandable versus static interbody devices: radiographic assessment of sagittal segmental and pelvic parameters.

    Science.gov (United States)

    Hawasli, Ammar H; Khalifeh, Jawad M; Chatrath, Ajay; Yarbrough, Chester K; Ray, Wilson Z

    2017-08-01

    OBJECTIVE Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) has been adopted as an alternative technique to hasten recovery and minimize postoperative morbidity. Advances in instrumentation technologies and operative techniques have evolved to maximize patient outcomes as well as radiographic results. The development of expandable interbody devices allows a surgeon to perform MIS-TLIF with minimal tissue disruption. However, sagittal segmental and pelvic radiographic outcomes after MIS-TLIF with expandable interbody devices are not well characterized. The object of this study is to evaluate the radiographic sagittal lumbar segmental and pelvic parameter outcomes of MIS-TLIF performed using an expandable interbody device. METHODS A retrospective review of MIS-TLIFs performed between 2014 and 2016 at a high-volume center was performed. Radiographic measurements were performed on lateral radiographs before and after MIS-TLIF with static or expandable interbody devices. Radiographic measurements included disc height, foraminal height, fused disc angle, lumbar lordosis, pelvic incidence, sacral slope, and pelvic tilt. Mismatch between pelvic incidence and lumbar lordosis were calculated for each radiograph. RESULTS A total of 48 MIS-TLIFs were performed, predominantly at the L4-5 level, in 44 patients. MIS-TLIF with an expandable interbody device led to a greater and more sustained increase in disc height when compared with static interbody devices. Foraminal height increased after MIS-TLIF with expandable but not with static interbody devices. MIS-TLIF with expandable interbody devices increased index-level segmental lordosis more than with static interbody devices. The increase in segmental lordosis was sustained in the patients with expandable interbody devices but not in patients with static interbody devices. For patients with a collapsed disc space, MIS-TLIF with an expandable interbody device provided superior and longer-lasting increases in

  12. Medication incidents reported to an online incident reporting system.

    LENUS (Irish Health Repository)

    Alrwisan, Adel

    2011-01-15

    AIMS: Approximately 20% of deaths from adverse events are related to medication incidents, costing the NHS an additional £500 million annually. Less than 5% of adverse events are reported. This study aims to assess the reporting rate of medication incidents in NHS facilities in the north east of Scotland, and to describe the types and outcomes of reported incidents among different services. Furthermore, we wished to quantify the proportion of reported incidents according to the reporters\\' profession. METHODS: A retrospective description was made of medication incidents reported to an online reporting system (DATIX) over a 46-month-period (July 2005 to April 2009). Reports originated from acute and community hospitals, mental health, and primary care facilities. RESULTS: Over the study period there were 2,666 incidents reported with a mean monthly reporting rate of 78.2\\/month (SD±16.9). 6.1% of all incidents resulted in harm, with insulin being the most commonly implicated medication. Nearly three-quarters (74.2%, n=1,978) of total incidents originated from acute hospitals. Administration incidents were implicated in the majority of the reported medication incidents (59%), followed by prescribing (10.8%) and dispensing (9.9%), while the nondescript "other medication incidents" accounted for 20.3% of total incidents. The majority of reports were made by nursing and midwifery staff (80%), with medical and dental professionals reporting the lowest number of incidents (n=56, 2%). CONCLUSIONS: The majority of medication incidents in this study were reported by nursing and midwifery staff, and were due to administration incidents. There is a clear need to elucidate the reasons for the limited contribution of the medical and dental professionals to reporting medication incidents.

  13. Survey of beam-beam limitations

    International Nuclear Information System (INIS)

    Courant, E.; Cornacchia, M.; Donald, M.M.R.; Evans, L.R.; Tazzari, S.; Wilson, E.J.N.

    1979-01-01

    The effect of beam-beam interaction is known to limit the luminosity of electron-positron storage rings and will, no doubt, limit the proton-antiproton collision scheme for the SPS. While theorists are struggling to explain this phenomenon it is more instructive to list their failures than their rather limited successes, in the hope that experiments may emerge which will direct their endeavors. The search for a description of a nonlinear system as it approaches the limit in which ordered motion breaks down, is the nub of the problem. It has engaged many fine mathematical intellects for decades and will no doubt continue to do so long after ISABELLE, the p antip and LEP are past achievements. Empirical scaling laws are emerging which relate electron machines to each other but their extrapolation to proton machines remain a very speculative exercise. Experimental data on proton limits is confined to one machine, the ISR, which does not normally suffer the beam-beam effect and where it must be artificially induced or simulated. This machine is also very different in important ways from the p antip collider. The gloomy picture which has emerged recently is that the fixed limits which were conventionally assumed for proton and electron machines can only be said to be valid for the machines which engendered them - the best guess that could be made at the time. They are very difficult to extrapolate to other sets of parameters

  14. Beam-width spreading of vortex beams in free space

    Science.gov (United States)

    Wang, Weiwei; Li, Jinhong; Duan, Meiling

    2018-01-01

    Based on the extended Huygens-Fresnel principle and the definition of second-order moments of the Wigner distribution function, the analytical expression for the beam-width spreading of Gaussian Schell-model (GSM) vortex beams in free space are derived, and used to study the influence of beam parameters on the beam-width spreading of GSM vortex beams. With the increment of the propagation distance, the beam-width spreading of GSM vortex beams will increase; the bigger the topological charge, spatial correlation length, wavelength and waist width are, the smaller the beam-width spreading is.

  15. Dose computation for therapeutic electron beams

    Science.gov (United States)

    Glegg, Martin Mackenzie

    The accuracy of electron dose calculations performed by two commercially available treatment planning computers, Varian Cadplan and Helax TMS, has been assessed. Measured values of absorbed dose delivered by a Varian 2100C linear accelerator, under a wide variety of irradiation conditions, were compared with doses calculated by the treatment planning computers. Much of the motivation for this work was provided by a requirement to verify the accuracy of calculated electron dose distributions in situations encountered clinically at Glasgow's Beatson Oncology Centre. Calculated dose distributions are required in a significant minority of electron treatments, usually in cases involving treatment to the head and neck. Here, therapeutic electron beams are subject to factors which may cause non-uniformity in the distribution of dose, and which may complicate the calculation of dose. The beam shape is often irregular, the beam may enter the patient at an oblique angle or at an extended source to skin distance (SSD), tissue inhomogeneities can alter the dose distribution, and tissue equivalent material (such as wax) may be added to reduce dose to critical organs. Technological advances have allowed the current generation of treatment planning computers to implement dose calculation algorithms with the ability to model electron beams in these complex situations. These calculations have, however, yet to be verified by measurement. This work has assessed the accuracy of calculations in a number of specific instances. Chapter two contains a comparison of measured and calculated planar electron isodose distributions. Three situations were considered: oblique incidence, incidence on an irregular surface (such as that which would be arise from the use of wax to reduce dose to spinal cord), and incidence on a phantom containing a small air cavity. Calculations were compared with measurements made by thermoluminescent dosimetry (TLD) in a WTe electron solid water phantom. Chapter

  16. Effect of the selective adsorption on the reactive scattering process of molecular beams from stepped surfaces

    International Nuclear Information System (INIS)

    Garcia, N.

    1977-01-01

    An indicative proposal which may explain the diffusion of incident atomic beams scattered by a crystal surface is made in terms of the selective adsorption mechanism. In this sense, the stepped metallic surfaces present characteristics which enhance the displacements and the lifetimes of the beams on the surface. This may be important for increasing the exchange reactive scattering of molecules from crystal surfaces

  17. Scattering of flexural waves in Euler-Bernoulli beams by short-range potentials

    DEFF Research Database (Denmark)

    Christiansen, Peter Leth; Iermakova, Sofia V.; Gaididei, Yuri B.

    2018-01-01

    Time-harmonic flexural waves on a beam and on two elastically coupled beams with short-range localized imperfections in the mass distribution and in the position dependant coupling are considered. Thus scattering of an incident wave solution to the Euler-Bernoulli equation by a Dirac delta function...

  18. Theoretical study of cylindrical energy analyzers for MeV range heavy ion beam probes

    International Nuclear Information System (INIS)

    Fujisawa, A.; Hamada, Y.

    1993-07-01

    A cylindrical energy analyzer with drift spaces is shown to have a second order focusing for beam incident angle when the deflection angle is properly chosen. The analyzer has a possibility to be applied to MeV range heavy ion beam probes, and will be also available for accurate particle energy measurements in many other fields. (author)

  19. Modelling pencil-beam divergence with the electron pencil-beam redefinition algorithm

    Science.gov (United States)

    Boyd, Robert A.; Hogstrom, Kenneth R.; White, R. Allen; Starkschall, George

    2001-11-01

    The electron pencil-beam redefinition algorithm (PBRA), which is used to calculate electron beam dose distributions, assumes that the virtual source of each pencil beam is identical to that of the broad beam incident on the patient. In the present work, a virtual source specific for each pencil beam is modelled by including the source distance as a pencil-beam parameter to be redefined with depth. To incorporate a variable pencil-beam source distance parameter, the transport equation was reformulated to explicitly model divergence resulting in the algorithm divPBRA. Allowing the virtual source position to vary with individual pencil beams is expected to better model the effects of heterogeneities on local electron fluence divergence (or convergence). Selected experiments from a measured data set developed at The University of Texas M D Anderson Cancer Center were used to evaluate the accuracy of the dose calculated using divPBRA. Results of the calculation showed that the theory accurately predicted the virtual source position in regions of side-scatter equilibrium and predicted reasonable virtual source positions in regions lacking side-scatter equilibrium (i.e. penumbra and in the vicinity and shadow of internal heterogeneities). Results of the evaluation showed the dose accuracy of divPBRA to be marginally better to that of PBRA, except in regions of extremely sharp dose perturbations, where the divPBRA calculations were significantly greater than the measured data. Dose calculations using divPBRA took 45% longer than those using PBRA. Therefore, we concluded that divPBRA offers no significant advantage over PBRA for the purposes of clinical treatment planning. However, the results were promising and divPBRA might prove useful if further modelling were to include large-angle scattering, low-energy delta rays and brehmsstrahlung.

  20. Modelling pencil-beam divergence with the electron pencil-beam redefinition algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Boyd, Robert A.; Hogstrom, Kenneth R.; Starkschall, George [Department of Radiation Physics, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); White, R. Allen [Department of Biomathematics, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States)

    2001-11-01

    The electron pencil-beam redefinition algorithm (PBRA), which is used to calculate electron beam dose distributions, assumes that the virtual source of each pencil beam is identical to that of the broad beam incident on the patient. In the present work, a virtual source specific for each pencil beam is modelled by including the source distance as a pencil-beam parameter to be redefined with depth. To incorporate a variable pencil-beam source distance parameter, the transport equation was reformulated to explicitly model divergence resulting in the algorithm divPBRA. Allowing the virtual source position to vary with individual pencil beams is expected to better model the effects of heterogeneities on local electron fluence divergence (or convergence). Selected experiments from a measured data set developed at The University of Texas M D Anderson Cancer Center were used to evaluate the accuracy of the dose calculated using divPBRA. Results of the calculation showed that the theory accurately predicted the virtual source position in regions of side-scatter equilibrium and predicted reasonable virtual source positions in regions lacking side-scatter equilibrium (i.e. penumbra and in the vicinity and shadow of internal heterogeneities). Results of the evaluation showed the dose accuracy of divPBRA to be marginally better to that of PBRA, except in regions of extremely sharp dose perturbations, where the divPBRA calculations were significantly greater than the measured data. Dose calculations using divPBRA took 45% longer than those using PBRA. Therefore, we concluded that divPBRA offers no significant advantage over PBRA for the purposes of clinical treatment planning. However, the results were promising and divPBRA might prove useful if further modelling were to include large-angle scattering, low-energy delta rays and brehmsstrahlung. (author)

  1. Modelling pencil-beam divergence with the electron pencil-beam redefinition algorithm.

    Science.gov (United States)

    Boyd, R A; Hogstrom, K R; White, R A; Starkschall, G

    2001-11-01

    The electron pencil-beam redefinition algorithm (PBRA), which is used to calculate electron beam dose distributions, assumes that the virtual source of each pencil beam is identical to that of the broad beam incident on the patient. In the present work, a virtual source specific for each pencil beam is modelled by including the source distance as a pencil-beam parameter to be redefined with depth. To incorporate a variable pencil-beam source distance parameter, the transport equation was reformulated to explicitly model divergence resulting in the algorithm divPBRA. Allowing the virtual source position to vary with individual pencil beams is expected to better model the effects of heterogeneities on local electron fluence divergence (or convergence). Selected experiments from a measured data set developed at The University of Texas M D Anderson Cancer Center were used to evaluate the accuracy of the dose calculated using divPBRA. Results of the calculation showed that the theory accurately predicted the virtual source position in regions of side-scatter equilibrium and predicted reasonable virtual source positions in regions lacking side-scatter equilibrium (i.e. penumbra and in the vicinity and shadow of internal heterogeneities). Results of the evaluation showed the dose accuracy of divPBRA to be marginally better to that of PBRA, except in regions of extremely sharp dose perturbations, where the divPBRA calculations were significantly greater than the measured data. Dose calculations using divPBRA took 45% longer than those using PBRA. Therefore, we concluded that divPBRA offers no significant advantage over PBRA for the purposes of clinical treatment planning. However, the results were promising and divPBRA might prove useful if further modelling were to include large-angle scattering, low-energy delta rays and brehmsstrahlung.

  2. Incident users of antipsychotics

    DEFF Research Database (Denmark)

    Baandrup, Lone; Kruse, Marie

    2016-01-01

    PURPOSE: In Denmark, as well as in many other countries, consumption of antipsychotics is on the rise, partly due to increasing off-label use. The aim of this study was to analyze and quantify the extent of off-label use and polypharmacy in incident users of antipsychotic medication, and to examine...... initial antipsychotic prescribing patterns and associated use of mental health care services. METHOD: Population-based cohort study linking the following Danish national registers: the Central Psychiatric Research Register, the Register of Medicinal Product Statistics, and Statistics Denmark. RESULTS...

  3. Electron Beam Lithography

    Science.gov (United States)

    Harriott, Lloyd R.

    1997-04-01

    Electron beams have played a significant role in semiconductor technology for more than twenty years. Early electron beam machines used a raster scanned beam spot to write patterns in electron-sensitive polymer resist materials. The main application of electron beam lithography has been in mask making. Despite the inherently high spatial resolution and wide process margins of electron beam lithography, the writing rate for semiconductor wafers has been too slow to be economically viable on a large scale. In the late 1970's, variable shape electron beam writing was developed, projecting a rectangular beam whose size can be varied for each "shot" exposure of a particular pattern, allowing some integrated circuits to be made economically where a variety of "customized" patterns are desired. In the cell or block projection electron beam exposure technique, a unit cell of a repetitive pattern is projected repeatedly to increase the level of parallelism. This can work well for highly repetitive patterns such as memory chips but is not well suited to complex varying patterns such as microprocessors. The rapid progress in the performance of integrated circuits has been largely driven by progress in optical lithography, through improvements in lens design and fabrication as well as the use of shorter wavelengths for the exposure radiation. Due to limitations from the opacity of lens and mask materials, it is unlikely that conventional optical printing methods can be used at wavelengths below 193 nm or feature sizes much below 180 nm. One candidate technology for a post-optical era is the Scattering with Angular Limitation Projection Electron-beam Lithography (SCALPEL) approach, which combines the high resolution and wide process latitude inherent in electron beam lithography with the throughput of a parallel projection system. A mask consisting of a low atomic number membrane and a high atomic number pattern layer is uniformly illuminated with high energy (100 ke

  4. Proton core-beam system in the expanding solar wind: Hybrid simulations

    Czech Academy of Sciences Publication Activity Database

    Hellinger, Petr; Trávníček, Pavel M.

    2011-01-01

    Roč. 116, A11 (2011), A11101/1-A11101/13 ISSN 0148-0227 R&D Projects: GA AV ČR IAA300420702 Grant - others:European Space Agency(XE) PECS contract No. 98068; European Commissions(XE) SWIFF (project 263340) Institutional research plan: CEZ:AV0Z30420517; CEZ:AV0Z10030501 Keywords : ELECTROMAGNETIC PROTON/PROTON INSTABILITIES * VELOCITY SPACE DIFFUSION * WAVE-WAVE SCATTERING * TEMPERATURE ANISOTROPY * PLASMA * DRIFT * DISTRIBUTIONS Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.021, year: 2011 http://www.agu.org/pubs/crossref/2011/2011JA016940.shtml

  5. Improving freight crash incident management.

    Science.gov (United States)

    2015-06-01

    The objective of this study was to determine the most effective way to mitigate the effect of freight : crash incidents on Louisiana freeways. Candidate incident management strategies were reviewed from : practice in other states and from those publi...

  6. Common Causes of Pesticide Incidents

    Science.gov (United States)

    There are many types of pesticide incidents. EPA staff analyze pesticide incident reports involving people (including children and farm workers), pets, domestic animals, wildlife including bees and other pollinators, and the environment.

  7. High bandwidth beam current monitor

    International Nuclear Information System (INIS)

    Baltrusaitis, R.M.; Ekdahl, C.A.; Cooper, R.G.; Peterson, E.; Warn, C.E.

    1993-01-01

    A stripline directional coupler beam current monitor capable of measuring the time structure of a 30-ps electron beam bunch has been developed. The time response performance of the monitor compares very well with Cherenkov light produced in quartz by the electron beam. The four-pickup monitor is now used on a routine basis for measuring the beam duration, tuning for optimized beam bunching, and centering the bunch in the beam pipe

  8. Inextendibility of expanding cosmological models with symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Dafermos, Mihalis [University of Cambridge, Department of Pure Mathematics and Mathematical Statistics, Wilberforce Road, Cambridge CB3 0WB (United Kingdom); Rendall, Alan D [Max Planck Institute for Gravitational Physics, Albert Einstein Institute, Am Muehlenberg 1, D-14476 Golm (Germany)

    2005-12-07

    A new criterion for inextendibility of expanding cosmological models with symmetry is presented. It is applied to derive a number of new results and to simplify the proofs of existing ones. In particular, it shows that the solutions of the Einstein-Vlasov system with T{sup 2} symmetry, including the vacuum solutions, are inextendible in the future. The technique introduced adds a qualitatively new element to the available tool-kit for studying strong cosmic censorship. (letter to the editor)

  9. Expanding the senses of drawing through colour

    OpenAIRE

    Moutinho, Natacha Antão; Durão, Maria João

    2013-01-01

    By equating the creative use of colour with the disciplinary boundaries of architecture, this paper integrates observations, reflections and insights on a variety of alternative graphic strategies, and also expands the meanings attached to a drawing when the significance of colour is highlighted within the creative process of architectural design. Through the observations of numerous drawings from Portuguese architects we have already detected several functions or uses of colour in the design...

  10. Expanding roles for GILT in immunity

    OpenAIRE

    West, Laura Ciaccia; Cresswell, Peter

    2012-01-01

    Gamma-interferon-inducible lysosomal thiol reductase (GILT), a thioredoxin-related oxidoreductase, functions in MHC class II-restricted antigen processing and MHC class I-restricted cross-presentation by reducing disulfide bonds of endocytosed proteins and facilitating their unfolding and optimal degradation. However, recent reports have greatly expanded our understanding of GILT’s function. Several studies of GILT and antigen processing have shown that the influence of GILT on the peptide re...

  11. Strings, Fivebranes and an Expanding Universe

    OpenAIRE

    Khuri, Ramzi R.; Pokotilov, Andriy

    2002-01-01

    It was recently shown that velocity-dependent forces between parallel fundamental strings moving apart in a $D-$dimensional spacetime implied an accelerating expanding universe in $D-1$-dimensional space-time. Exact solutions were obtained for the early time expansion in $D=5,6$. Here we show that this result also holds for fundamental strings in the background of a fivebrane, and argue that the feature of an accelerating universe would hold for more general $p$-brane-seeded models.

  12. Expanding Policy Imagination in Political Economy

    DEFF Research Database (Denmark)

    Seabrooke, Leonard

    2006-01-01

    Much of the literature in political economy seeks to capture an essential insight into the evolution of political and economic systems to provide a foundation for policy advice. This article suggests that attempts to nut out the kernels of change often restrict rather than expand policy imagination...... be implemented. Historical sociology provides a way to generate information about contextual constellations through two "tonics": intentional rationality and social mechanisms. With the assistance of these tonics, historical sociology widens political economy's policy imagination....

  13. Beam-beam limit in e+e- circular colliders

    International Nuclear Information System (INIS)

    Ohmi, K.; Tawada, M.; Kamada, S.; Oide, K.; Cai, Y.; Qiang, J.

    2004-01-01

    Beam-beam effects limit the luminosity of circular colliders. Once the bunch population exceeds a threshold, the luminosity increases at a slower rate. This phenomenon is called the beam-beam limit. Onset of the beam-beam limit has been analyzed with various simulation methods based on the weak-strong and strong-strong models. We have observed that an incoherent phenomenon is mainly concerned in the beam-beam limit. The simulation have shown that equilibrium distributions of the two colliding beams are distorted from Gaussians when the luminosity is limited. The beam-beam limit is estimated to be ξ∼0.1 for a B factory with damping time of several thousand turns

  14. Increasing incidence of pyogenic spondylodiscitis

    DEFF Research Database (Denmark)

    Kehrer, Michala; Pedersen, Court; Jensen, Thøger G

    2014-01-01

    Smaller studies indicate that the incidence of pyogenic spondylodiscitis is increasing, possible related to a growing elderly population. Data supporting this is sparse, and we therefore studied patient characteristics and changes in spondylodiscitis incidence 1995-2008.......Smaller studies indicate that the incidence of pyogenic spondylodiscitis is increasing, possible related to a growing elderly population. Data supporting this is sparse, and we therefore studied patient characteristics and changes in spondylodiscitis incidence 1995-2008....

  15. Depth profiling of aluminium metal using slow positron beam ...

    African Journals Online (AJOL)

    Slow positron beam Doppler-broadening technique was used to study depth profiling of aluminium metals sample. The variation of the line-shape parameters with incident positron energy was studied. Also, the depth profile of the S parameter was investigated. The positron implantation profile and backscattering fraction for ...

  16. Structural and electrical properties of swift heavy ion beam irradiated ...

    Indian Academy of Sciences (India)

    Unknown

    at the Co/Si interface for investigation of ion beam mixing at various doses: 8 × 1012, 5 × 1013 and 1 × 1014 cm–2. Formation of different phases of cobalt silicide is identified by the grazing incidence X-ray diffraction. (GIXRD) technique, which shows enhancement of intermixing and silicide formation as a result of irradiation ...

  17. Two dimensional simulation of ion beam-plasm interaction | Echi ...

    African Journals Online (AJOL)

    Hybrid plasma simulation is a model in which different components of the plasma are treated differently. In this work the ions are treated as particles while the electrons are treated as a neutralizing background fluid through which electric signals may propagate. Deuterium ion beams incident on the tritium plasma interact ...

  18. Programming balanced optical beam splitters in white paint

    NARCIS (Netherlands)

    Huisman, S.R.; Huisman, T.J.; Huisman, T.J.; Goorden, S.A.; Mosk, Allard; Pinkse, Pepijn Willemszoon Harry

    2014-01-01

    Wavefront shaping allows for ultimate control of light propagation in multiple-scattering media by adaptive manipulation of incident waves. We shine two separate wavefront-shaped beams on a layer of dry white paint to create two enhanced output spots of equal intensity. We experimentally confirm by

  19. Use of radiation processing technology gradually expands in industry

    International Nuclear Information System (INIS)

    Anon.

    1989-01-01

    The use of radioisotopes and radiation is expanding in the fields of industries and medicine with a high potentiality of the application to environmental protection. The technology transfer on the use of isotopes and radiation is progressing in the framework of international cooperation. But the industry has maintained wait and see attitude on the commercialization of food irradiation. Such present features were the highlight in the 19th Japan Conference on Radiation and Radioisotopes held on November 14-16. 72 papers from 19 countries were presented and discussed in 13 sessions. The progress of accelerator technology has contributed to the expansion of radiation processing market. The importance of the application of isotopes and radiation to environmental protection has been gradually acknowledged, and the electron beam treatment of flue gas for acid rain abatement and the elimination of chlorinated ethylene from drinking water were discussed. Drastic change has not been seen in the climate of food irradiation, however there are several positive indicators which support the prediction of slow but steady progress in the commercialization of the process and the trade of irradiated foods. (K.I.)

  20. Optimisation of electron beam characteristics by simulated annealing

    International Nuclear Information System (INIS)

    Ebert, M.A.; University of Adelaide, SA; Hoban, P.W.

    1996-01-01

    Full text: With the development of technology in the field of treatment beam delivery, the possibility of tailoring radiation beams (via manipulation of the beam's phase space) is foreseeable. This investigation involved evaluating a method for determining the characteristics of pure electron beams which provided dose distributions that best approximated desired distributions. The aim is to determine which degrees of freedom are advantageous and worth pursuing in a clinical setting. A simulated annealing routine was developed to determine optimum electron beam characteristics. A set of beam elements are defined at the surface of a homogeneous water equivalent phantom defining discrete positions and angles of incidence, and electron energies. The optimal weighting of these elements is determined by the (generally approximate) solution to the linear equation, Dw = d, where d represents the dose distribution calculated over the phantom, w the vector of (50 - 2x10 4 ) beam element relative weights, and D a normalised matrix of dose deposition kernels. In the iterative annealing procedure, beam elements are randomly selected and beam weighting distributions are sampled and used to perturb the selected elements. Perturbations are accepted or rejected according to standard simulated annealing criteria. The result (after the algorithm has terminated due to meeting an iteration or optimisation specification) is an approximate solution for the beam weight vector (w) specified by the above equation. This technique has been applied for several sample dose distributions and phase space restrictions. An example is given of the phase space obtained when endeavouring to conform to a rectangular 100% dose region with polyenergetic though normally incident electrons. For regular distributions, intuitive conclusions regarding the benefits of energy/angular manipulation may be made, whereas for complex distributions, variations in intensity over beam elements of varying energy and

  1. Characterization of commercial expandable graphite fire retardants

    Energy Technology Data Exchange (ETDEWEB)

    Focke, Walter Wilhelm, E-mail: walter.focke@up.ac.za; Badenhorst, Heinrich; Mhike, Washington; Kruger, Hermanus Joachim; Lombaard, Dewan

    2014-05-01

    Highlights: • Expandable graphite is less well-ordered than its graphite bisulfate progenitor. • It includes graphite oxide as a randomly interstratified phase. • CO{sub 2}, CO and SO{sub 2} are released during thermal-driven exfoliation. - Abstract: Thermal analysis and other techniques were employed to characterize two expandable graphite samples. The expansion onset temperatures of the expandable graphite's were ca. 220 °C and 300 °C respectively. The key finding is that the commercial products are not just pure graphite intercalation compounds with sulfuric acid species intercalated as guest ions and molecules in between intact graphene layers. A more realistic model is proposed where graphite oxide-like layers are also randomly interstratified in the graphite flakes. These graphite oxide-like layers comprise highly oxidized graphene sheets which contain many different oxygen-containing functional groups. This model explains the high oxygen to sulfur atomic ratios found in both elemental analysis of the neat materials and in the gas generated during the main exfoliation event.

  2. Intermittency Statistics in the Expanding Solar Wind

    Science.gov (United States)

    Cuesta, M. E.; Parashar, T. N.; Matthaeus, W. H.

    2017-12-01

    The solar wind is observed to be turbulent. One of the open questions in solar wind research is how the turbulence evolves as the solar wind expands to great distances. Some studies have focused on evolution of the outer scale but not much has been done to understand how intermittency evolves in the expanding wind beyond 1 AU (see [1,2]). We use magnetic field data from Voyager I spacecraft from 1 to 10AU to study the evolution of statistics of magnetic discontinuities. We perform various statistical tests on these discontinuities and make connections to the physical processes occurring in the expanding wind.[1] Tsurutani, Bruce T., and Edward J. Smith. "Interplanetary discontinuities: Temporal variations and the radial gradient from 1 to 8.5 AU." Journal of Geophysical Research: Space Physics 84.A6 (1979): 2773-2787.[2] Greco, A., et al. "Evidence for nonlinear development of magnetohydrodynamic scale intermittency in the inner heliosphere." The Astrophysical Journal 749.2 (2012): 105.

  3. 3D Terahertz Beam Profiling

    DEFF Research Database (Denmark)

    Pedersen, Pernille Klarskov; Strikwerda, Andrew; Jepsen, Peter Uhd

    2013-01-01

    We present a characterization of THz beams generated in both a two-color air plasma and in a LiNbO3 crystal. Using a commercial THz camera, we record intensity images as a function of distance through the beam waist, from which we extract 2D beam profiles and visualize our measurements into 3D beam...... profiles. For the two-color air-plasma, we measure a conical beam profile that is focused to a bell-shape at the beam waist, whereas we observe a Gaussian beam profile for the THz beam generated from the LiNbO3 crystal....

  4. Incident Management: Process into Practice

    Science.gov (United States)

    Isaac, Gayle; Moore, Brian

    2011-01-01

    Tornados, shootings, fires--these are emergencies that require fast action by school district personnel, but they are not the only incidents that require risk management. The authors have introduced the National Incident Management System (NIMS) and the Incident Command System (ICS) and assured that these systems can help educators plan for and…

  5. Forming of space charge wave with broad frequency spectrum in helical relativistic two-stream electron beams

    DEFF Research Database (Denmark)

    Lysenko, Alexander V.; Volk, Iurii I.; Serozhko, A.

    2017-01-01

    expands with the increase of the beam entrance angle. Moreover, we obtain that utilizing helical electron beams in multiharmonic two-stream superheterodyne free-electron lasers leads to the improvement of their amplification characteristics, the frequency spectrum broadening in multiharmonic signal...

  6. Luminescent beam stop

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, Diane; Morton, Simon A.

    2017-10-25

    This disclosure provides systems, methods, and apparatus related to beam stops. In one aspect, a device comprises a luminescent material, a beam stop plate, and an optical fiber. The luminescent material is a parallelepiped having a first side and a second side that are squares and having a third side that is a rectangle or a square. The first side and the second side are perpendicular to the third side. The beam stop plate is attached to the first side of the luminescent material. The optical fiber has a first end and a second end, with the first end of the optical fiber attached to the third side of the luminescent material.

  7. WORKSHOP: Crystalline beams

    International Nuclear Information System (INIS)

    Anon.

    1989-01-01

    Following pioneer work by specialists at the Soviet Novosibirsk Laboratory some ten years ago, interest developed in the possibility of 'freezing' ion beams in storage rings by pushing cooling (to smooth out beam behaviour) to its limits, the final goal being to lock the ions into a neat crystal pattern. After advances by groups working on laser cooled ions in traps, and with several cooling rings now in operation, a workshop on crystalline ion beams was organized recently by the GSI (Darmstadt) Laboratory and held at Wertheim in Germany

  8. Mass spectrometer beam monitor

    International Nuclear Information System (INIS)

    McKinney, C.R.

    1980-01-01

    Improved apparatus and system were developed for determining the field desorption characteristics of a sample prior to field desorption mass spectrometry. A portion of the ion beam from the ion source is disabled so that it is undeflected in the beam analyzer. When sample ions are detected by a sensor in this portion of the beam it is then allowed to be deflected and the mass analysis occurs. Thus the source position, temperature and electric field strength can be varied until ions are produced from the sample and the field desorption characteristics can be determined. The source characteristics can be varied either automatically or manually. (DN)

  9. Is every quasar beamed?

    Science.gov (United States)

    Barthel, Peter D.

    1989-01-01

    A companion paper (Barthel et al.) reports the discovery of superluminal motion in the core of 4C 34.47, the largest known quasi-stellar radio source. Superluminal motion, the apparent continuity of small- and large-scale one-sided radio jets, and the recently established depolarization asymmetry in luminous quasars find a natural explanation in the effects of relativistic beaming. In the frameworkof of this relativistic beaming model, the available data imply that all radio-loud quasars are beamed toward the earth. Powerful radio galaxies may well form the unbeamed parent population. Radio-quiet QSOs and powerful infrared galaxies can be unified using similar orientation effects.

  10. Secondary beams at GANIL

    International Nuclear Information System (INIS)

    Doubre, H.

    1992-01-01

    GANIL, a user's facility since 1983, can deliver a broad spectrum of heavy-ion beams, from He to U, to well-equipped experimental areas. Their very large intensities are to be exploited to produce secondary beams, either using the fragmentation method (beams at energy per nucleon larger than 30 MeV/u), or the ISOL method. With the latter one, these ions have to be re-accelerated. The project of a cyclotron as a post-accelerator is described. (author) 11 refs.; 7 figs.; 3 tabs

  11. ICFA Beam Dynamics Newsletter

    Energy Technology Data Exchange (ETDEWEB)

    Pikin, A. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2017-11-21

    Electron beam ion sources technology made significant progress since 1968 when this method of producing highly charged ions in a potential trap within electron beam was proposed by E. Donets. Better understanding of physical processes in EBIS, technological advances and better simulation tools determined significant progress in key EBIS parameters: electron beam current and current density, ion trap capacity, attainable charge states. Greatly increased the scope of EBIS and EBIT applications. An attempt is made to compile some of EBIS engineering problems and solutions and to demonstrate a present stage of understanding the processes and approaches to build a better EBIS.

  12. Field size and dose distribution of electron beam

    International Nuclear Information System (INIS)

    Kang, Wee Saing

    1980-01-01

    The author concerns some relations between the field size and dose distribution of electron beams. The doses of electron beams are measured by either an ion chamber with an electrometer or by film for dosimetry. We analyzes qualitatively some relations; the energy of incident electron beams and depths of maximum dose, field sizes of electron beams and depth of maximum dose, field size and scatter factor, electron energy and scatter factor, collimator shape and scatter factor, electron energy and surface dose, field size and surface dose, field size and central axis depth dose, and field size and practical range. He meets with some results. They are that the field size of electron beam has influence on the depth of maximum dose, scatter factor, surface dose and central axis depth dose, scatter factor depends on the field size and energy of electron beam, and the shape of the collimator, and the depth of maximum dose and the surface dose depend on the energy of electron beam, but the practical range of electron beam is independent of field size

  13. Precision atomic beam density characterization by diode laser absorption spectroscopy

    International Nuclear Information System (INIS)

    Oxley, Paul; Wihbey, Joseph

    2016-01-01

    We provide experimental and theoretical details of a simple technique to determine absolute line-of-sight integrated atomic beam densities based on resonant laser absorption. In our experiments, a thermal lithium beam is chopped on and off while the frequency of a laser crossing the beam at right angles is scanned slowly across the resonance transition. A lock-in amplifier detects the laser absorption signal at the chop frequency from which the atomic density is determined. The accuracy of our experimental method is confirmed using the related technique of wavelength modulation spectroscopy. For beams which absorb of order 1% of the incident laser light, our measurements allow the beam density to be determined to an accuracy better than 5% and with a precision of 3% on a time scale of order 1 s. Fractional absorptions of order 10 −5 are detectable on a one-minute time scale when we employ a double laser beam technique which limits laser intensity noise. For a lithium beam with a thickness of 9 mm, we have measured atomic densities as low as 5 × 10 4 atoms cm −3 . The simplicity of our technique and the details we provide should allow our method to be easily implemented in most atomic or molecular beam apparatuses.

  14. Precision atomic beam density characterization by diode laser absorption spectroscopy.

    Science.gov (United States)

    Oxley, Paul; Wihbey, Joseph

    2016-09-01

    We provide experimental and theoretical details of a simple technique to determine absolute line-of-sight integrated atomic beam densities based on resonant laser absorption. In our experiments, a thermal lithium beam is chopped on and off while the frequency of a laser crossing the beam at right angles is scanned slowly across the resonance transition. A lock-in amplifier detects the laser absorption signal at the chop frequency from which the atomic density is determined. The accuracy of our experimental method is confirmed using the related technique of wavelength modulation spectroscopy. For beams which absorb of order 1% of the incident laser light, our measurements allow the beam density to be determined to an accuracy better than 5% and with a precision of 3% on a time scale of order 1 s. Fractional absorptions of order 10 -5 are detectable on a one-minute time scale when we employ a double laser beam technique which limits laser intensity noise. For a lithium beam with a thickness of 9 mm, we have measured atomic densities as low as 5 × 10 4 atoms cm -3 . The simplicity of our technique and the details we provide should allow our method to be easily implemented in most atomic or molecular beam apparatuses.

  15. Generation of monoenergetic ion beams with a laser accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Pfotenhauer, Sebastian M.

    2009-01-29

    A method for the generation of monoenergetic proton and ion beams from a laser-based particle accelerator is presented. This method utilizes the unique space-charge effects occurring during relativistic laser-plasma interactions on solid targets in combination with a dot-like particle source. Due to this unique interaction geometry, MeV proton beams with an intrinsically narrow energy spectrum were obtained, for the first time, from a micrometer-scale laser accelerator. Over the past three years, the acceleration scheme has been consistently improved to enhance both the maximum particle energy and the reliability of the setup. The achieved degree of reliability allowed to derive the first scaling laws specifically for monoenergetic proton beams. Furthermore, the acceleration scheme was expanded on other target materials, enabling the generation of monoenergetic carbon beams. The experimental work was strongly supported by the parallel development of a complex theoretical model, which fully accounts for the observations and is in excellent agreement with numerical simulations. The presented results have an extraordinarily broad scope way beyond the current thesis: The availability of monoenergetic ion beams from a compact laser-plasma beam source - in conjunction with the unique properties of laser-produced particle beams - addresses a number of outstanding applications in fundamental research, material science and medical physics, and will help to shape a new generation of accelerators. (orig.)

  16. Generation of monoenergetic ion beams with a laser accelerator

    International Nuclear Information System (INIS)

    Pfotenhauer, Sebastian M.

    2009-01-01

    A method for the generation of monoenergetic proton and ion beams from a laser-based particle accelerator is presented. This method utilizes the unique space-charge effects occurring during relativistic laser-plasma interactions on solid targets in combination with a dot-like particle source. Due to this unique interaction geometry, MeV proton beams with an intrinsically narrow energy spectrum were obtained, for the first time, from a micrometer-scale laser accelerator. Over the past three years, the acceleration scheme has been consistently improved to enhance both the maximum particle energy and the reliability of the setup. The achieved degree of reliability allowed to derive the first scaling laws specifically for monoenergetic proton beams. Furthermore, the acceleration scheme was expanded on other target materials, enabling the generation of monoenergetic carbon beams. The experimental work was strongly supported by the parallel development of a complex theoretical model, which fully accounts for the observations and is in excellent agreement with numerical simulations. The presented results have an extraordinarily broad scope way beyond the current thesis: The availability of monoenergetic ion beams from a compact laser-plasma beam source - in conjunction with the unique properties of laser-produced particle beams - addresses a number of outstanding applications in fundamental research, material science and medical physics, and will help to shape a new generation of accelerators. (orig.)

  17. Investigation of effect of electron beam on various polyethylene blends

    CERN Document Server

    Morshedian, J

    2003-01-01

    With regards to the expanding usage of electron beams irradiation in polymer industries such as sterilization of polymeric disposable medical products; cable manufacturing; pipes, heat shrinkable materials, etc. In this project the effect of electron beam on polyethylene used in manufacturing of pipe and heat shrinkable products was studied. Results showed that by increasing the applied dose on samples; the crosslink density would increase and polymers with tertiary carbon atoms in their backbone structure tend to crosslink more readily. The melting temperature and crystallinity percent decreased and degradation temperature increased. Density in low doses decreased and in high doses increased.

  18. DART: a simulation code for charged particle beams

    International Nuclear Information System (INIS)

    White, R.C.; Barr, W.L.; Moir, R.W.

    1988-01-01

    This paper presents a recently modified verion of the 2-D DART code designed to simulate the behavior of a beam of charged particles whose paths are affected by electric and magnetic fields. This code was originally used to design laboratory-scale and full-scale beam direct converters. Since then, its utility has been expanded to allow more general applications. The simulation technique includes space charge, secondary electron effects, and neutral gas ionization. Calculations of electrode placement and energy conversion efficiency are described. Basic operation procedures are given including sample input files and output. 7 refs., 18 figs

  19. Neutral particle beam intensity controller

    Science.gov (United States)

    Dagenhart, W.K.

    1984-05-29

    The neutral beam intensity controller is based on selected magnetic defocusing of the ion beam prior to neutralization. The defocused portion of the beam is dumped onto a beam dump disposed perpendicular to the beam axis. Selective defocusing is accomplished by means of a magnetic field generator disposed about the neutralizer so that the field is transverse to the beam axis. The magnetic field intensity is varied to provide the selected partial beam defocusing of the ions prior to neutralization. The desired focused neutral beam portion passes along the beam path through a defining aperture in the beam dump, thereby controlling the desired fraction of neutral particles transmitted to a utilization device without altering the kinetic energy level of the desired neutral particle fraction. By proper selection of the magnetic field intensity, virtually zero through 100% intensity control of the neutral beam is achieved.

  20. Acoustic manipulation: Bessel beams and active carriers

    Science.gov (United States)

    Rajabi, Majid; Mojahed, Alireza

    2017-10-01

    In this paper, we address the interaction of zero-order acoustic Bessel beams as an acoustic manipulation tool, with an active spherical shell, as a carrier in drug, agent, or material delivery systems, in order to investigate the controllability of exerted acoustic radiation force as the driver. The active body is comprised of a spherical elastic shell stimulated in its monopole mode of vibrations with the same frequency as the incident wave field via an internally bonded and spatially uniformly excited piezoelectric actuator. The main aim of this work is to examine the performance of a nondiffracting and self-reconstructing zero-order Bessel beam to obtain the full manipulability condition of active carriers in comparison with the case of a plane wave field. The results unveil some unique potentials of the Bessel beams in the company of active carriers, with emphasis on the consumed power of the actuation system. This paper will widen the path toward the single-beam robust acoustic manipulation techniques and may lead to the prospect of combined tweezers and fields, with applications in delivery systems, microswimmers, and trapper designs.

  1. A phase-space beam position monitor for synchrotron radiation

    International Nuclear Information System (INIS)

    Samadi, Nazanin; Bassey, Bassey; Martinson, Mercedes; Belev, George; Dallin, Les; Jong, Mark de; Chapman, Dean

    2015-01-01

    A system has been developed to measure the vertical position and angle of the electron beam at a single location from a synchrotron source. The system uses a monochromator tuned to the absorption edge of a contrast material and has a sensitivity comparable with other beam position monitors. The stability of the photon beam position on synchrotron beamlines is critical for most if not all synchrotron radiation experiments. The position of the beam at the experiment or optical element location is set by the position and angle of the electron beam source as it traverses the magnetic field of the bend-magnet or insertion device. Thus an ideal photon beam monitor would be able to simultaneously measure the photon beam’s position and angle, and thus infer the electron beam’s position in phase space. X-ray diffraction is commonly used to prepare monochromatic beams on X-ray beamlines usually in the form of a double-crystal monochromator. Diffraction couples the photon wavelength or energy to the incident angle on the lattice planes within the crystal. The beam from such a monochromator will contain a spread of energies due to the vertical divergence of the photon beam from the source. This range of energies can easily cover the absorption edge of a filter element such as iodine at 33.17 keV. A vertical profile measurement of the photon beam footprint with and without the filter can be used to determine the vertical centroid position and angle of the photon beam. In the measurements described here an imaging detector is used to measure these vertical profiles with an iodine filter that horizontally covers part of the monochromatic beam. The goal was to investigate the use of a combined monochromator, filter and detector as a phase-space beam position monitor. The system was tested for sensitivity to position and angle under a number of synchrotron operating conditions, such as normal operations and special operating modes where the photon beam is intentionally altered

  2. Electron beam curing paint

    International Nuclear Information System (INIS)

    Maruyama, Tsutomu

    1991-04-01

    Electron beam curing (EBC) type paint is paint that is specially prepared so that it can be cured and dried by electron beam irradiation. Electron beam irradiation achieves hardly any curing and drying of ordinary normal-temperature drying type paint or heat-drying type paint. The main type of paint in which an electron beam produces a curing reaction is one in which a radical polymerization reaction takes place under irradiation. The use of this EBC painting - drying system has been considered for a variety of fields since it has a number of special features such as the fact that the paint dries instantaneously, no heat is applied and no solvent is used. (Author)

  3. Electron Beam Ion Sources

    CERN Document Server

    Zschornacka, G.; Thorn, A.

    2013-12-16

    Electron beam ion sources (EBISs) are ion sources that work based on the principle of electron impact ionization, allowing the production of very highly charged ions. The ions produced can be extracted as a DC ion beam as well as ion pulses of different time structures. In comparison to most of the other known ion sources, EBISs feature ion beams with very good beam emittances and a low energy spread. Furthermore, EBISs are excellent sources of photons (X-rays, ultraviolet, extreme ultraviolet, visible light) from highly charged ions. This chapter gives an overview of EBIS physics, the principle of operation, and the known technical solutions. Using examples, the performance of EBISs as well as their applications in various fields of basic research, technology and medicine are discussed.

  4. Final focus test beam

    International Nuclear Information System (INIS)

    1991-03-01

    This report discusses the following: the Final Focus Test Beam Project; optical design; magnets; instrumentation; magnetic measurement and BPM calibration; mechanical alignment and stabilization; vacuum system; power supplies; control system; radiation shielding and personnel protection; infrastructure; and administration

  5. HIRENASD Beam FEM

    Data.gov (United States)

    National Aeronautics and Space Administration — This contains attempts to create BEAM FEM model. I have started a Blog to discuss this... please put your comments there and I will attempt to keep everything...

  6. Single Beam Holography.

    Science.gov (United States)

    Chen, Hsuan; Ruterbusch, Paul H.

    1979-01-01

    Discusses how holography can be used as part of undergraduate physics laboratories. The authors propose a single beam technique of holography, which will reduce the recording scheme as well as relax the isolation requirements. (HM)

  7. Beam-beam diagnostics from closed-orbit distortion

    Energy Technology Data Exchange (ETDEWEB)

    Furman, M.; Chin, Y.H.; Eden, J. [Lawrence Berkeley Lab., CA (United States); Kozanecki, W. [DAPNIA/SPP, CEN Saclay Gif-sur-Yvette, (FR)]|[Stanford Linear Accelerator Center, Menlo Park, CA (United States); Tennyson, J.; Ziemann, V. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)

    1992-07-01

    We study the applicability of beam-beam deflection techniques as a tuning tool for asymmetric B factories, focusing on PEP-II as an example. Assuming that the closed orbits of the two beams are separated vertically at the interaction point by a local orbit bump that is nominally closed, we calculate the residual beam orbit distortions due to the beam-beam interaction. Difference orbit measurements, performed at points conveniently distant from the interaction point (IP), provide distinct signatures that can be used to maintain the beams in collision and perform detailed optical diagnostics at the IP. A proposal to test this method experimentally at the TRISTAN ring is briefly discussed.

  8. SPIDER beam dump as diagnostic of the particle beam

    Energy Technology Data Exchange (ETDEWEB)

    Zaupa, M., E-mail: matteo.zaupa@igi.cnr.it; Sartori, E. [Università degli Studi di Padova, Via 8 Febbraio 2, Padova 35122 (Italy); Consorzio RFX, Corso Stati Uniti 4, Padova 35127 (Italy); Dalla Palma, M.; Brombin, M.; Pasqualotto, R. [Consorzio RFX, Corso Stati Uniti 4, Padova 35127 (Italy)

    2016-11-15

    The beam power produced by the negative ion source for the production of ion of deuterium extracted from RF plasma is mainly absorbed by the beam dump component which has been designed also for measuring the temperatures on the dumping panels for beam diagnostics. A finite element code has been developed to characterize, by thermo-hydraulic analysis, the sensitivity of the beam dump to the different beam parameters. The results prove the capability of diagnosing the beam divergence and the horizontal misalignment, while the entity of the halo fraction appears hardly detectable without considering the other foreseen diagnostics like tomography and beam emission spectroscopy.

  9. Beam-beam simulation of Möbius-modified CESR

    Science.gov (United States)

    Talman, R.; Malitsky, N.; Koyama, T.

    1997-05-01

    Colliding beam experiments at CESR with beams made round by running on the coupling resonance have been performed,(E. Young et al.), abstract, this conference and runs are planned with the beams made round by Möbius modification.(R. Talman, Phys. Rev. Lett. 74), 1590, (1995) Performance in these configurations has been simulated using TEAPOT++ tracking, map generation, stochastic, and beam-beam modules within the Unified Accelerator Libraries(N. Malitsky et al.), abstract, this conference The true CESR lattice including sextupoles and element apertures is used. Outputs from the calculation include beam profile modification, tune optimization, maximum luminosity, and (with extrapolation) beam lifetimes.

  10. Backscatter spectra measurements of the two beams on the same cone on Shenguang-III laser facility

    Science.gov (United States)

    Zha, Weiyi; Yang, Dong; Xu, Tao; Liu, Yonggang; Wang, Feng; Peng, Xiaoshi; Li, Yulong; Wei, Huiyue; Liu, Xiangming; Mei, Yu; Yan, Yadong; He, Junhua; Li, Zhichao; Li, Sanwei; Jiang, Xiaohua; Guo, Liang; Xie, Xufei; Pan, Kaiqiang; Liu, Shenye; Jiang, Shaoen; Zhang, Baohan; Ding, Yongkun

    2018-01-01

    In laser driven hohlraums, laser beams on the same incident cone may have different beam and plasma conditions, causing beam-to-beam backscatter difference and subsequent azimuthal variations in the x-ray drive on the capsule. To elucidate the large variation of backscatter proportion from beam to beam in some gas-filled hohlraum shots on Shenguang-III, two 28.5° beams have been measured with the Stimulated Raman Scattering (SRS) time-resolved spectra. A bifurcated fiber is used to sample two beams and then coupled to a spectrometer and streak camera combination to reduce the cost. The SRS spectra, characterized by a broad wavelength, were further corrected considering the temporal distortion and intensity modulation caused by components along the light path. This measurement will improve the understanding of the beam propagation inside the hohlraum and related laser plasma instabilities.

  11. Beam-beam simulations: dynamical effects and beam-beam limit for LEP3

    CERN Document Server

    Ohmi, K

    2012-01-01

    Beam-beam simulations are reported for LEP3 and TLEP-H, including a rough tune scan. The results suggest that to achieve the design luminosity in LEP3, 10% higher bunch population may be necessary, while TLEP-H can achieve the design performance without any changes. The simulations indicate that the large synchrotron tune, in conjunction with a large hourglass effect, degrades the luminosity performance. This talk was given at CERN on 4 December 2012.

  12. Betatrons with kiloampere beams

    International Nuclear Information System (INIS)

    Peterson, J.M.

    1982-11-01

    Although the magnetic-induction method of acceleration used in the betatron is inherently capable of accelerating intense particle beams to high energy, many beam-instability questions arise when beams in the kilo-ampere range are considered. The intense electromagnetic fields produced by the beam, and by the image currents and charges induced in the surrounding walls, can produce very disruptive effects. Several unstable modes of collective oscillation are possible; the suppression of any one of them usually involves energy spread for Landau damping and careful design of the electrical character of the vacuum chamber. The various design criteria are often mutually incompatible. Space-charge detuning can be severe unless large beam apertures and high-energy injection are used. In order to have an acceptably low degree of space-charge detuning in the acceleration of a 10-kilo-ampere electron beam, for example, an injection energy on the order of 50 MeV seems necessary, in which case the forces due to nearby wall images can have a larger effect than the internal forces of the beam. A method of image compensation was invented for reducing the net image forces; it serves also to decrease the longitudinal beam impedance and thus helps alleviate the longitudinal instability as well. In order to avoid the ion-electron collective instability a vacuum in the range of 10 - 8 torr is required for an acceleration time of 1 millisecond. A multi-ring betatron system using the 50-MeV Advanced Test Accelerator at LLNL as an injector was conceptually designed

  13. LHCb: Beam Pipe portrait

    CERN Multimedia

    LHCb, Collaboration

    2005-01-01

    The proton beams circulate in the accelerator in Ultra High Vacuum to make them interact only with each other when colliding at the interaction point. A special beam pipe "holds" the vacuum where they pass through the LHCb detector: it has to be mechanically very strong to stand the difference in pressure between the vacuum inside it and the air in the cavern but also be as transparent as possible for the particles originating in the proton−proton collisions.

  14. LHCb: Beam Pipe

    CERN Multimedia

    LHCb, Collaboration

    2005-01-01

    The proton beams circulate in the accelerator in Ultra High Vacuum to make them interact only with each other when colliding at the interaction point. A special beam pipe "holds" the vacuum where they pass through the LHCb detector:it has to be mechanically very strong to stand the difference in pressure between the vacuum inside it and the air in the cavern but also be as transparent as possible for the particles originating in the proton−proton collisions.

  15. PARTICLE BEAMS: Frontier course

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    Driven by the quest for higher energies and optimal physics conditions, the behaviour of particle beams in accelerators and storage rings is the subject of increasing attention. Thus the second course organized jointly by the US and CERN Accelerator Schools looked towards the frontiers of particle beam knowledge. The programme held at South Padre Island, Texas, from 23-29 October attracted 125 participants including some 35 from Europe

  16. LHC First Beam 2008

    CERN Multimedia

    Tuura, L

    2008-01-01

    The CMS Centre played a major part in the LHC First Beam Event on September 10th 2008: it was a central point for CMS, hosting journalists from all over the world and providing live link-ups to collaborating institutes as well as, of course, monitoring events as they happened at Point 5. It was also a venue for celebration as the beam completed circuits of the LHC in both directions, passing successfully through the detector (Courtesy of Lassi Tuura)

  17. Terascale Beam-Beam Simulations for Tevatron, RHIC and LHC

    Energy Technology Data Exchange (ETDEWEB)

    Qiang, J.

    2005-05-16

    In this paper, we report on recent advances in terascale simulations of the beam-beam interaction in Tevatron, RHIC and LHC.Computational methods for self consistent calculation of beam-beam forces are reviewed. New method for solving the two-dimensional Poisson equation with open boundary conditions is proposed and tested. This new spectral-finite difference method is a factor of four faster than the widely used FFT based Green function method for beam-beam interaction on axis. We also present applications to the study of antiproton losses during the injection stage at Tevatron, to the study of multiple bunch coherent beam-beam modes at RHIC, and to the study of beam-beam driven emittance growth at LHC.

  18. Terascale Beam-Beam Simulations for Tevatron, RHIC and LHC

    International Nuclear Information System (INIS)

    Qiang, J.

    2005-01-01

    In this paper, we report on recent advances in terascale simulations of the beam-beam interaction in Tevatron, RHIC and LHC.Computational methods for self consistent calculation of beam-beam forces are reviewed. New method for solving the two-dimensional Poisson equation with open boundary conditions is proposed and tested. This new spectral-finite difference method is a factor of four faster than the widely used FFT based Green function method for beam-beam interaction on axis. We also present applications to the study of antiproton losses during the injection stage at Tevatron, to the study of multiple bunch coherent beam-beam modes at RHIC, and to the study of beam-beam driven emittance growth at LHC

  19. Transverse equilibria in linear collider beam-beam collisions

    International Nuclear Information System (INIS)

    Rosenzweig, J.B.; Chen, Pisin

    1991-01-01

    It has been observed in simulations of the beam-beam interaction in linear colliders that a near equilibrium pinched state of the colliding beams develops when the disruption parameter is large (D much-gt 1). In this state the beam transverse density distributions are peaked at center, with long tails. The authors present here an analytical model of the equilibrium approached by the beams, that of a generalized Bennett pinch which develops through collisionless damping due to the strong nonlinearity of the beam-beam interaction. In order to calculate the equilibrium pinched beam size, an estimation of the rms emittance growth is made which takes into account the partial adiabaticity of the collision. This pinched beam size is used to derive the luminosity enhancement factors whose scaling is in agreement with the simulation results for both D and thermal factor A = σ z /β * large, and explains the previously noted cubic relationship between round and flat beam enhancement factors

  20. Beam structure studies of low-energy ion beams

    Science.gov (United States)

    Saadatmand, K.; Schneider, J. D.; Geisik, C.; Stevens, R. R.

    1991-05-01

    The ion beam structure at various axial positions along the beam-transport line has been monitored and studied utilizing a fluor screen and a video camera. The fluor material is aluminum oxide that is plasma-jet sprayed onto the surface of an aluminum or a water-cooled copper substrate. The visual representation of the beam structure is digitized and enhanced through use of false-color coding and displayed on a TV monitor for the on-line viewing by the experimentalist. Digitized video signals are stored for further off-line processing and extracting more information about the beam, such as beam profiles. This inexpensive and effective diagnostic enables the experimentalist to observe the real-time beam response (such as evolution of the beam structure, shifts in the beam intensity at various spatial locations within the beam perimeter, and shifts in the beam center and position) to parameter changes.

  1. Polarized proton beams

    International Nuclear Information System (INIS)

    Roser, T.

    1995-01-01

    The acceleration of polarized proton beams in circular accelerators is complicated by the presence of numerous depolarizing spin resonances. Careful and tedious minimization of polarization loss at each of these resonances allowed acceleration of polarized proton beams up to 22 GeV. It has been the hope that Siberian Snakes, which are local spin rotators inserted into ring accelerators, would eliminate these resonances and allow acceleration of polarized beams with the same ease and efficiency that is now routine for unpolarized beams. First tests at IUCF with a full Siberian Snake showed that the spin dynamics with a Snake can be understood in detail. The author now has results of the first tests of a partial Siberian Snake at the AGS, accelerating polarized protons to an energy of about 25 GeV. These successful tests of storage and acceleration of polarized proton beams open up new possibilities such as stored polarized beams for internal target experiments and high energy polarized proton colliders

  2. Aortic Regurgitation in Patients Undergoing Transcatheter Aortic Valve Replacement With the Self-Expanding CoreValve Versus the Balloon-Expandable SAPIEN XT Valve.

    Science.gov (United States)

    Kiramijyan, Sarkis; Magalhaes, Marco A; Koifman, Edward; Didier, Romain; Escarcega, Ricardo O; Baker, Nevin C; Negi, Smita I; Minha, Sa'ar; Torguson, Rebecca; Jiaxiang, Gai; Asch, Federico M; Wang, Zuyue; Okubagzi, Petros; Gaglia, Michael A; Ben-Dor, Itsik; Satler, Lowell F; Pichard, Augusto D; Waksman, Ron

    2016-05-01

    The incidence of aortic regurgitation (AR) after transcatheter aortic valve replacement (TAVR) in a self-expanding and a balloon-expandable system is controversial. This study aimed to examine the incidence and severity of post-TAVR AR with the CoreValve (CV) versus the Edwards XT Valve (XT). Baseline, procedural, and postprocedural inhospital outcomes were compared. The primary end point was the incidence of post-TAVR AR of any severity, assessed with a transthoracic echocardiogram, in the CV versus XT groups. A multivariate logistic regression analysis was completed to evaluate for correlates of the primary end point. The secondary end points included the change in severity of AR at 30-day and 1-year follow-up. A total of 223 consecutive patients (53% men, mean age 82 years) who had transfemoral TAVR with either a CV (n = 119) or XT (n = 104) were evaluated. The rates of post-TAVR AR in the groups were similar, and there was no evidence of more-than-moderate AR in either group. There were significant differences in the rates of intraprocedural balloon postdilation with the CV (17.1%) versus XT valve (5.8%; p = 0.009) and in the rates of intraprocedural implantation of a second valve-in-valve prosthesis with the CV (9.9%) versus XT valve (2.2%; p = 0.036). There were no significant differences in inhospital safety outcomes between the 2 groups. In conclusion, the incidence of post-TAVR AR is similar between the CV and the XT valve when performed by experienced operators using optimal intraprocedural strategies, as deemed appropriate, to mitigate the severity of AR. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Expanding Technological Frames Towards Mediated Collaboration

    DEFF Research Database (Denmark)

    Bjørn, Pernille; Scupola, Ada; Fitzgerald, Brian

    2006-01-01

    This paper provides an in-depth analysis of technological and social factors leading to the successful adoption of groupware in a virtual team in educational setting. Drawing on a theoretical framework based on the concept of technological frames, we conducted an action research study to analyze...... the chronological sequence of events leading to groupware adoption. We argue that groupware adoption can be conceptualized as a three-step process of expanding and aligning individual technological frames towards groupware: The first step comprises activities facilitating participants in articulation and evaluation...... collaborative practice and use of technology, and that this activity cannot take place at the outset....

  4. Expanding the Bethe/Gauge dictionary

    Science.gov (United States)

    Bullimore, Mathew; Kim, Hee-Cheol; Lukowski, Tomasz

    2017-11-01

    We expand the Bethe/Gauge dictionary between the XXX Heisenberg spin chain and 2d N = (2, 2) supersymmetric gauge theories to include aspects of the algebraic Bethe ansatz. We construct the wave functions of off-shell Bethe states as orbifold defects in the A-twisted supersymmetric gauge theory and study their correlation functions. We also present an alternative description of off-shell Bethe states as boundary conditions in an effective N = 4 supersymmetric quantum mechanics. Finally, we interpret spin chain R-matrices as correlation functions of Janus interfaces for mass parameters in the supersymmetric quantum mechanics.

  5. Ion Accelerator Merges Several Beams

    Science.gov (United States)

    Aston, G.

    1984-01-01

    Intense ion beam formed by merging multiple ion beamlets into one concentrated beam. Beamlet holes in graphite screen and focusing grids arranged in hexagonal pattern. Merged beam passes through single hole in each of aluminum accelerator and decelerator grids. Ion extraction efficiency, beam intensity, and focusing improved.

  6. Summary of Session 4 "Beam Energy"

    CERN Document Server

    Siemko, A

    2011-01-01

    In this session, the possible scenarios for the beam energy in the LHC 2011 run were discussed. The benefits for the physics reach for physics operations at s larger than 7 TeV were reviewed. The main goal was, however, to establish the necessary information for a sound risk analysis by assessing the probability of thermal runaway and evaluating the consequences of a hypothetical incident. A new technique to improve the knowledge of joint resistances of the cooper busbars and therefore the reliability of the risk analysis has also been discussed.

  7. Reversible wavefront shaping between Gaussian and Airy beams by mimicking gravitational field

    Science.gov (United States)

    Wang, Xiangyang; Liu, Hui; Sheng, Chong; Zhu, Shining

    2018-02-01

    In this paper, we experimentally demonstrate reversible wavefront shaping through mimicking gravitational field. A gradient-index micro-structured optical waveguide with special refractive index profile was constructed whose effective index satisfying a gravitational field profile. Inside the waveguide, an incident broad Gaussian beam is firstly transformed into an accelerating beam, and the generated accelerating beam is gradually changed back to a Gaussian beam afterwards. To validate our experiment, we performed full-wave continuum simulations that agree with the experimental results. Furthermore, a theoretical model was established to describe the evolution of the laser beam based on Landau’s method, showing that the accelerating beam behaves like the Airy beam in the small range in which the linear potential approaches zero. To our knowledge, such a reversible wavefront shaping technique has not been reported before.

  8. Method of measuring a profile of the density of charged particles in a particle beam

    International Nuclear Information System (INIS)

    Hyman, L.G.; Jankowski, D.J.

    1975-01-01

    A profile of the relative density of charged particles in a beam is obtained by disposing a number of rods parallel to each other in a plane perpendicular to the beam and shadowing the beam. A second number of rods is disposed perpendicular to the first rods in a plane perpendicular to the beam and also shadowing the beam. Irradiation of the rods by the beam of charged particles creates radioactive isotopes in a quantity proportional to the number of charged particles incident upon the rods. Measurement of the radioactivity of each of the rods provides a measure of the quantity of radioactive material generated thereby and, together with the location of the rods, provides information sufficient to identify a profile of the density of charged particles in the beam

  9. Broadband and high-efficiency vortex beam generator based on a hybrid helix array.

    Science.gov (United States)

    Fang, Chaoqun; Wu, Chao; Gong, Zhijie; Zhao, Song; Sun, Anqi; Wei, Zeyong; Li, Hongqiang

    2018-04-01

    The vortex beam which carries the orbital angular momentum has versatile applications, such as high-resolution imaging, optical communications, and particle manipulation. Generating vortex beams with the Pancharatnam-Berry (PB) phase has drawn considerable attention for its unique spin-to-orbital conversion features. Despite the PB phase being frequency independent, an optical element with broadband high-efficiency circular polarization conversion feature is still needed for the broadband high-efficiency vortex beam generation. In this work, a broadband and high-efficiency vortex beam generator based on the PB phase is built with a hybrid helix array. Such devices can generate vortex beams with arbitrary topological charge. Moreover, vortex beams with opposite topological charge can be generated with an opposite handedness incident beam that propagates backward. The measured efficiency of our device is above 65% for a wide frequency range, with the relative bandwidth of 46.5%.

  10. Pediatric melanoma: incidence, treatment, and prognosis

    Directory of Open Access Journals (Sweden)

    Saiyed FK

    2017-04-01

    Full Text Available Faiez K Saiyed,1 Emma C Hamilton,1 Mary T Austin,1,2 1Department of Pediatric Surgery, McGovern Medical School, 2Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA Abstract: The purpose of this review is to outline recent advancements in diagnosis, treatment, and prevention of pediatric melanoma. Despite the recent decline in incidence, it continues to be the deadliest form of skin cancer in children and adolescents. Pediatric melanoma presents differently from adult melanoma; thus, the traditional asymmetry, border irregularity, color variegation, diameter >6 mm, and evolution (ABCDE criteria have been modified to include features unique to pediatric melanoma (amelanotic, bleeding/bump, color uniformity, de novo/any diameter, evolution of mole. Surgical and medical management of pediatric melanoma continues to derive guidelines from adult melanoma treatment. However, more drug trials are being conducted to determine the specific impact of drug combinations on pediatric patients. Alongside medical and surgical treatment, prevention is a central component of battling the incidence, as ultraviolet (UV-related mutations play a central role in the vast majority of pediatric melanoma cases. Aggressive prevention measures targeting sun safety and tanning bed usage have shown positive sun-safety behavior trends, as well as the potential to decrease melanomas that manifest later in life. As research into the field of pediatric melanoma continues to expand, a prevention paradigm needs to continue on a community-wide level. Keywords: melanoma, pediatric, adolescent, childhood

  11. An expanded dengue syndrome patient with manifestation myocarditis: case report

    Science.gov (United States)

    Arifijanto, M. V.; Luqmana, H. P.; Rusli, M.; Bramantono

    2018-03-01

    Dengue infection may manifest asymptomatic, dengue fever, dengue hemorrhagic fever, dengue shock syndrome. However, atypical manifestations in other organs have been increasingly reported and called expanded dengue syndrome. One of the cardiac complications in dengue is myocarditis. An 18-year-old woman complains of high fever since 3 days, epistaxis, chest pain, dyspnea, and vomiting. Laboratory examination obtained thrombocytopenia, hemoconcentration, NS1, IgG-IgM dengue positive, CKMB and Troponin- I increase. Electrocardiogram result ischemic anterior-posterior. Echocardiography results hyperechogenic on myocardial suspicious a myocarditis. The patient was diagnosed with acute myocarditis and dengue hemorrhagic fever. Condition improved after five days of treatment. Cardiac complications in dengue are now increasingly observed with the most common case is myocarditis. The main mechanism of dengue myocarditis is still unknown though both direct viral infection and immune mediated damage have been suggested to be the cause of myocardial damage. The low incidence of dengue myocarditis is because it’s asymptomatic and diagnosis is easily missed. Almost all cases of dengue myocarditis are self-limiting and severe myocarditis leading to dilated cardiomyopathy is extremely rare. There have been reported a patient with dengue hemorrhagic fever with manifestation myocarditis. Condition improve with supportive management.

  12. Beam abort detection of SSRF

    International Nuclear Information System (INIS)

    Feng Chenxia; Zhou Weimin; Leng Yongbin

    2010-01-01

    Beam abort signal is a timing signal of the SSRF (Shanghai Synchrotron Radiation Facility) storage ring. It is used to synchronize BPM processor Libera logging beam position data to identify beam abort source and improve the stability of accelerator. The concept design and engineering design of beam abort trigger module are introduced in this paper, and lab test results of this module using RF signal source also presented. Online beam test results show that this module has achieved design goal, could be used to log beam position data before beam abort. (authors)

  13. A SIMPLE METHOD FOR MEASURING THE ELECTRON-BEAM MAGNETIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Halavanau, A. [Fermilab; Qiang, G. [Tsinghua U., Beijing, Dept. Eng. Phys.; Wisniewski, E. [Argonne; Ha, G. [POSTECH, Pohang; Power, J. [Argonne; Piot, P. [Fermilab

    2016-10-18

    There are a number of projects that require magnetized beams, such as electron cooling or aiding in “flat” beam transforms. Here we explore a simple technique to characterize the magnetization, observed through the angular momentum of magnetized beams. These beams are produced through photoemission. The generating drive laser first passes through microlens arrays (fly-eye light condensers) to form a transversely modulated pulse incident on the photocathode surface [1]. The resulting charge distribution is then accelerated from the photocathode. We explore the evolution of the pattern via the relative shearing of the beamlets, providing information about the angular momentum. This method is illustrated through numerical simulations and preliminary measurements carried out at the Argonne Wakefield Accelerator (AWA) facility are presented.

  14. Driver beam-led EURISOL target design constraints

    CERN Document Server

    Noah, Etam; Catherall, Richard; Kadi, Yacine; Kharoua, Cyril; Lettry, Jacques

    2008-01-01

    The EURISOL (European Isotope Separation Online) Design Study is addressing new high power target design challenges. A three-step method [1] was proposed to split the high power linac proton driver beam into one $H^{-}$ branch for the 4 $MW_{b}$ [2] mercury target that produces radioactive ion beams (RIB) via spallation neutroninduced fission in a secondary actinide target and three 100 $kW_{b}$ $H^{+}$ branches for the direct targets producing RIBs via fragmentation and spallation reactions. This scheme minimises transient thermo-mechanical stresses on targets and preserves the cw nature of the driver beam in the four branches. The heat load for oxides, carbides, refractory metal foils and liquid metals is driven by the incident proton driver beam while for actinides, exothermic fission reactions are an additional contribution. This paper discusses the constraints that are specific to each class of material and the target design strategies.

  15. Expectations for prospective applications of new beam technology to atomic energy research

    International Nuclear Information System (INIS)

    Tomimasu, Takio; Yamazaki, Tetsuo; Tanaka, Ryuichi; Tanigawa, Shoichiro; Konashi, Kenji; Mizumoti, Motoharu.

    1991-01-01

    Recently, the new beam technology based on high energy electron beam, for example free electron laser, low speed positrons and so on, has developed remarkably. Moreover, also in the field of ion beams, toward the utilization of further high level, the plans of using micro-beams, heightening energy, increasing electric current and so on are in progress. In near future, it is expected that the advanced application of such new beam technology expands more and more in the fields of materials, physical properties, isotope separation, biology, medical science, medical treatment and so on. In this report, placing emphasis on the examples of application, the development and application of new beam technology are described. Takasaki ion accelerators for advanced radiation application in Japan Atomic Energy Research Institute, the generation of low speed positrons and the utilization for physical property studies, the annihilation treatment of long life radioactive nuclides, and the generation of free electron laser and its application are reported. (K.I.)

  16. Historical Notes on the Expanding Universe

    Science.gov (United States)

    Way, Michael J.; Belenkyi, Ari; Nussbaumer, Harry; Peacock, John

    2014-01-01

    The article Measuring the Hubble constant by Mario Livio and Adam Riess (Physics Today, October 2013, page 41) reviewed studies of the expanding universe from the 1920s to the present. Although the history of the subject underwent considerable compression to fit the length of a magazine article, we think it may leave a misleading impression of some of the key steps to our current understanding. We therefore offer the following clarifications. Most significantly, papers by Arthur Eddington and by Willem de Sitter in 1930, who successfully promoted Georges Lematres 1927 article for the Scientific Society of Brussels, effected a paradigm shift in interpretation of extragalactic redshifts in 1930. Before then, the astronomical community was generally unaware of the existence of nonstatic cosmological solutions and did not broadly appreciate that redshifts could be thought of locally as Doppler shifts in an expanding matter distribution. Certainly, in 1929 Edwin Hubble referred only to the de Sitter solution of 1917. At the time, the relation between distance and redshift predicted in that model was generally seen purely as a manifestation of static spacetime curvature.

  17. RI beam factory and its expected pioneering work

    International Nuclear Information System (INIS)

    Yano, Yasushige

    1996-01-01

    The RARF (RIKEN Accelerator Research Facility) houses an intermediate-energy heavy-ion accelerator complex consisting of a K540-MeV ring cyclotron (RRC) and a couple of different types of the injectors: a variable-frequency heavy-ion linac and a K70-MeV AVF cyclotron. One of remarkable features of this facility is capability of supplying light-atomic-mass RI (radioactive isotope) beams with the world-highest level of intensities by the projectile-fragment separator, RIPS. In these several years nuclear physicists have opened up a quite new and fascinating heavy-ion science exploiting such RI beams. In order to further promote this new science, the RARF proposes 'RIKEN RI Beam Factory' as a next facility-expanding project. The factory takes the aim at providing RI beams covering over the whole atomic-mass range with the world-highest intensities in a wide energy range up to several hundreds MeV/nucleon. To realize the 'Factory' a K2500-MeV superconducting ring cyclotron will be built which boosts output energies of the RRC beams up to 400 MeV/nucleon for light ions and up to 100 MeV/nucleon for very heavy ions, preserving their beam intensities (typically 1 pμA). RI beams will be generated by the projectile fragmentation. A new type of experimental installation called 'MUSES' (Multi-USe Experimental Storage rings) will also be constructed. It consists of an accumulator-cooler ring, booster synchrotron ring and double storage rings. With MUSES, various types of unique colliding experiments will become possible: ion-ion merging or head-on collisions; collisions of either electrons or X-rays with ion (stable isotope or RI) beams; internal target experiments; and atomic and molecular physics with cooler electron beams. (author)

  18. A Rapidly Expanding Bose-Einstein Condensate: An Expanding Universe in the Lab

    Science.gov (United States)

    Eckel, S.; Kumar, A.; Jacobson, T.; Spielman, I. B.; Campbell, G. K.

    2018-04-01

    We study the dynamics of a supersonically expanding, ring-shaped Bose-Einstein condensate both experimentally and theoretically. The expansion redshifts long-wavelength excitations, as in an expanding universe. After expansion, energy in the radial mode leads to the production of bulk topological excitations—solitons and vortices—driving the production of a large number of azimuthal phonons and, at late times, causing stochastic persistent currents. These complex nonlinear dynamics, fueled by the energy stored coherently in one mode, are reminiscent of a type of "preheating" that may have taken place at the end of inflation.

  19. Beam-beam observations in the Relativistic Heavy Ion Collider

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Y. [Brookhaven National Laboratory (BNL), Upton, NY (United States); Fischer, W. [Brookhaven National Laboratory (BNL), Upton, NY (United States); White, S. [Brookhaven National Laboratory (BNL), Upton, NY (United States)

    2015-06-24

    The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory has been operating since 2000. Over the past decade, thanks to the continuously increased bunch intensity and reduced β*s at the interaction points, the maximum peak luminosity in the polarized proton operation has been increased by more than two orders of magnitude. In this article, we first present the beam-beam observations in the previous RHIC polarized proton runs. Then we analyze the mechanisms for the beam loss and emittance growth in the presence of beam-beam interaction. The operational challenges and limitations imposed by beam-beam interaction and their remedies are also presented. In the end, we briefly introduce head-on beam-beam compensation with electron lenses in RHIC.

  20. A 10 MHz beam counter and a multiplicity detector for the E864 spectrometer

    Science.gov (United States)

    Haridas, P.; Pless, I. A.; Van Buren, G.; Tomasi, J.; Rabin, M. S. Z.; Barish, K.; Majka, R. D.

    1997-02-01

    The E864 experiment at BNL requires a beam counter and multiplicity detector system that can perform at an incident beam rate of 10 7 Au ions per second. We have developed and tested a 150 μm thick quartz Cherenkov beam counter and a scintillator based multiplicity-trigger counter during the first run of this experiment in 1994. We obtained a time resolution of 78 ps for the beam counter at an incident beam rate 5 × 10 5 Hz and 100 ps at a rate of 1 × 10 7 Hz. Pulse height discrimination is used to obtain a minimum bias and a 10% centrality trigger from the multiplicity detectors. The multiplicity counter has a time resolution of 250 ps.

  1. Nanoscale orbital angular momentum beam instabilities in engineered nonlinear colloidal media

    Science.gov (United States)

    Sun, Jingbo; Silahli, Salih Z.; Walasik, Wiktor; Li, Qi; Johnson, Eric; Litchinitser, Natalia M.

    2018-03-01

    In this letter, we experimentally demonstrate the evolution of the optical vortex beams of different topological charges propagating in engineered nano-colloidal suspension of negative polarizability with saturable nonlinearities. Due to the high power of the incident beam, the modulation instability leads to an exponential growth of weak perturbations and thus splits the original vortex beam into a necklace beam consisting of several bright spots. The number of observed bright spots is intrinsically determined by the topological charge of the incident beam and agrees well with the predictions of our linear stability analysis and numerical simulations. Besides contributing to the fundamental science of light-matter interactions in engineered soft-matter media, this work opens new opportunities for dynamic optical manipulation and transmission of light through scattering media as well as formation of complex optical patterns and light filamentation in naturally existing colloids such as fog and clouds.

  2. A 10 MHz beam counter and a multiplicity detector for the E864 spectrometer

    International Nuclear Information System (INIS)

    Haridas, P.; Pless, I.A.; Buren, G. van; Tomasi, J.; Rabin, M.S.Z.; Barish, K.; Majka, R.D.

    1997-01-01

    The E864 experiment at BNL requires a beam counter and multiplicity detector system that can perform at an incident beam rate of 10 7 Au ions per second. We have developed and tested a 150 μm thick quartz Cherenkov beam counter and a scintillator based multiplicity-trigger counter during the first run of this experiment in 1994. We obtained a time resolution of 78 ps for the beam counter at an incident beam rate 5 x 10 5 Hz and 100 ps at a rate of 1 x 10 7 Hz. Pulse height discrimination is used to obtain a minimum bias and a 10% centrality trigger from the multiplicity detectors. The multiplicity counter has a time resolution of 250 ps. (orig.)

  3. Adaptive Laguerre-Gaussian variant of the Gaussian beam expansion method.

    Science.gov (United States)

    Cagniot, Emmanuel; Fromager, Michael; Ait-Ameur, Kamel

    2009-11-01

    A variant of the Gaussian beam expansion method consists in expanding the Bessel function J0 appearing in the Fresnel-Kirchhoff integral into a finite sum of complex Gaussian functions to derive an analytical expression for a Laguerre-Gaussian beam diffracted through a hard-edge aperture. However, the validity range of the approximation depends on the number of expansion coefficients that are obtained by optimization-computation directly. We propose another solution consisting in expanding J0 onto a set of collimated Laguerre-Gaussian functions whose waist depends on their number and then, depending on its argument, predicting the suitable number of expansion functions to calculate the integral recursively.

  4. ICFA Beam Dynamics Newsletter

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Zvi I.; Kuczewski A.; Altinbas, Z.; Beavis, D.; Belomestnykh,; Dai, J. et al

    2012-07-01

    The Collider-Accelerator Department at Brookhaven National Laboratory is building a high-brightness 500 mA capable Energy Recovery Linac (ERL) as one of its main R&D thrusts towards eRHIC, the polarized electron - hadron collider as an upgrade of the operating RHIC facility. The ERL is in final assembly stages, with injection commisioning starting in October 2012. The objective of this ERL is to serve as a platform for R&D into high current ERL, in particular issues of halo generation and control, Higher-Order Mode (HOM) issues, coherent emissions for the beam and high-brightness, high-power beam generation and preservation. The R&D ERL features a superconducting laser-photocathode RF gun with a high quantum efficiency photoccathode served with a load-lock cathode delivery system, a highly damped 5-cell accelerating cavity, a highly flexible single-pass loop and a comprehensive system of beam instrumentation. In this ICFA Beam Dynamics Newsletter article we will describe the ERL in a degree of detail that is not usually found in regular publications. We will discuss the various systems of the ERL, following the electrons from the photocathode to the beam dump, cover the control system, machine protection etc and summarize with the status of the ERL systems.

  5. Beam Time Accounting

    CERN Document Server

    Seitova, Diana

    2016-01-01

    ISOLDE is one of the leading research facilities in the field of nuclear physics. A proton beam with an energy 1.4 GeV coming from the Proton Synchrotron Booster (PSB) hits one of the targets at ISOLDE and produces Radioactive Ion Beams (RIBs). Then, the RIBs of interest is selected and delivered to the different experimental stations. In order to deliver the beam to the certain experimental station, the positions of the devices along the beamline should satisfy certain conditions. The purpose of this project is to define the conditions for the beam to pass through the different beamlines and to store the data about device’s status for later analysis and statistics, so it would be possible to know when the beam was used for different experiments. The data with the settings of the different devices is saved in the Timber database and the first steps for making virtual devices to compile the status of the beamlines were completed.

  6. Bringing up beams

    CERN Document Server

    Katarina Anthony

    2013-01-01

    Last month, commissioning began on CERN’s newest linear accelerator: Linac4. As the replacement machine for Linac2, Linac4 will take a negative hydrogen ion beam to a staggering 160 MeV. We check in to see how the Linac4 team is preparing its machine for its new role as the first link in the accelerator chain.   The Linac4 3 MeV beam line, with the ion source in the back, the RFQ in the middle and the chopping line in the front. On 14 November, members of the Linac4 collaboration and the CERN Operations Group were brought together for their first “real day” in the Linac4 Control Room. Together, they successfully accelerated their first hydrogen ion beam to 3 MeV. It was an exciting moment for everyone involved and marked the start of one of the most critical commissioning phases for the new accelerator. At the start of the Linac4 beam line sits the CERN-made Radio Frequency Quadrupole (RFQ). This vital piece of machinery takes the beam from 45 keV to 3 MeV in ju...

  7. A better beam quality

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    Progress has been made on two fronts, providing physics data and preparing for higher intensities. Over the Whitsun weekend of May 22 to 24, 5 fills for physics provided almost 30 hours of stable colliding beams, all with bunch intensities around 2x1010 protons and at a β* of 2m. The first three of these fills were with 6 bunches per beam, giving 3 pairs of collisions in all experiments. For the other two fills, the number of bunches per beam was increased to 13, giving 8 pairs of colliding bunches, and for the first time luminosities were pushed above 1029 cm-2s-1, 2 orders of magnitude higher than first collisions in March. In between and after these physics fills, nominal bunches of 1011 protons were successfully ramped and brought into collision in ATLAS and CMS for the first time (not in stable beam conditions and without squeeze). Event rates seen by the experiments were in the expected range for these conditions. In the middle of this work, a short fill with beams of 7 nominal bunches was ...

  8. Paul Collier : Balancing beams

    CERN Multimedia

    2009-01-01

    As former head of AB Operations, Paul Collier and his group were in the ‘cockpit’ for the LHC’s maiden voyage - piloting the first beam around the ring. But now, as Head of the Beams Department, he will need his feet firmly on the ground in order to balance all the beam activities at CERN. "As Department Head, I’ll have less direct contact with the machines," Collier says with a hint of regret. "I’ll still obviously be very involved, but they won’t actually let me loose in front of the keyboard anymore!" As the new Head of the BE Department, Collier will be in charge of nearly 400 people, and will oversee all the beam activities, including the preparations for the longest period of beam operation in the history of CERN. In the new organization, the BE, TE and EN Departments have been grouped together in the Accelerator and Technology Sector. "‘Partnership’ is a key word for the three departments," says Collier. "The n...

  9. Lightweight HPC beam OMEGA

    Science.gov (United States)

    Sýkora, Michal; Jedlinský, Petr; Komanec, Jan

    2017-09-01

    In the design and construction of precast bridge structures, a general goal is to achieve the maximum possible span length. Often, the weight of individual beams makes them difficult to handle, which may be a limiting factor in achieving the desired span. The design of the OMEGA beam aims to solve a part of these problems. It is a thin-walled shell made of prestressed high-performance concrete (HPC) in the shape of inverted Ω character. The concrete shell with prestressed strands is fitted with a non-stressed tendon already in the casting yard and is more easily transported and installed on the site. The shells are subsequently completed with mild steel reinforcement and cores are cast in situ together with the deck. The OMEGA beams can also be used as an alternative to steel - concrete composite bridges. Due to the higher production complexity, OMEGA beam can hardly substitute conventional prestressed beams like T or PETRA completely, but it can be a useful alternative for specific construction needs.

  10. Active beam integrator for high power coherent lasers

    Energy Technology Data Exchange (ETDEWEB)

    Laguarta, F.; Armengol, J.; Vega, F.; Lupon, N. [Univ. Politecnica de Catalunya, Terrassa (Spain). Dept. d`Optica i Optometria

    1996-12-31

    In laser materials processing applications it is often necessary to work with uniform intensity distributions. This goal is quite difficult to achieve when dealing with high power laser beams, and becomes critical for a successful application involving surface heat treatment of non-metallic materials. The authors have designed and tested a very simple beam shaper for transforming the initial intensity distribution of a CO{sub 2} laser beam mode into a more uniform intensity profile. The beam shaper is a two-faceted mirror for active integration of high power coherent laser beams. After reflection in the faceted mirror, a TEM00 or TEM01 CO{sub 2} laser beam is divided into two beamlets that overlap to give a more uniform intensity distribution. A sharp interference pattern due to the high spatial coherence of the incident beam appears. This interference pattern is actively integrated by a high-frequency longitudinal displacement of one of the facets. This provides a change in the relative phase of the two beamlets, and consequently the interference pattern vibrates and its contribution to the intensity distribution averages out. When sweeping this distribution over a sample, a uniform amount of energy is deposited at every point of its surface. It must be emphasized that unlike multifaceted mirrors, the two-facet integrator may provide uniform intensity profiles over any working distance. Finally, as in other integration devices an imaging system may be used to obtain a spot of the shape and the size desired for a particular application.

  11. Metal impurity injection into DIVA plasmas with a Q-switched laser beam

    International Nuclear Information System (INIS)

    Yamauchi, Toshihiko; Nagami, Masayuki; Sengoku, Seio; Kumagai, Katsuaki

    1978-08-01

    Metal impurity injection into DIVA plasmas with a Q-switched ruby laser beam is described. Metal materials used are aluminium and gold. The Q-switched laser beam is incident onto a thin metal film thickness about 0.2 μm coated on pyrex glass plate surface. The metal film is vaporized by the laser beam and injected into DIVA plasma. The laser-beam injection method has advantages of sharp profile of vaporized metal, easy control of vaporized metal quantity and injection rate control of metal vapor. (author)

  12. Hydrodynamic simulations of light ion beam-matter interactions: ablative acceleration of thin foils

    International Nuclear Information System (INIS)

    Devore, C.R.; Gardner, J.H.; Boris, J.P.; Mosher, D.

    1984-01-01

    A one-dimensional model is used to study the hydrodynamic response of thin foils to bombardment by an intense proton beam. The beam targets are single- and multilayer planar foils of gold and polystyrene. The main conclusion is that the efficiency of conversion of incident beam energy to directed kinetic energy of the target is maximized by using a multilayer design. For beam parameters associated with the Gamble II device at the Naval Research Laboratory, the simulations yield payload velocities of over 5 cm/μs and energy conversion efficiencies of over 30%. The implications of these results for inertial confinement fusion research are discussed. (author)

  13. A beam position monitor for low current dc beams

    International Nuclear Information System (INIS)

    Adderley, P.; Barry, W.; Heefner, J.; Kloeppel, P.; Rossmanith, R.; Wise, M.; Jachim, S.

    1989-01-01

    The 4 GeV recirculating linac, CEBAF, if presently under construction and will produce a CW beam with average current between.1 and 200 μA. In order to measure beam position, the beam current will be amplitude modulated at a frequency of 10 MHz. The modulation is detected by an inductive loop type monitor with electronics sensitive only to the modulation frequency. The first test with beam from the CEBAF injector indicate that beam position can be measured with an accuracy of .1 mm at a modulated beam current of 1 μA. 1 ref., 6 figs., 1 tab

  14. Beam-beam studies for FCC-hh

    CERN Document Server

    AUTHOR|(CDS)2068329; Pieloni, Tatiana; Buffat, Xavier; Furuseth, Sondre Vik

    2017-01-01

    The Future Circular Collider hadron-hadron (FCC-hh) design study is currently exploring different IR design possibilities including round and flat optics or different crossing schemes. The present study intends to evaluate each scenario from the beam-beam effects point of view. In particular the single particle long term stability to maximize beam lifetimes and luminosity reach is used to quantify the differences. The impact of strong head on interactions on the beam quality and lifetime is addressed by means of GPU accelerated simulations code featuring a weak-strong 6-dimensional beam-beam interaction.

  15. High intensity beam dump for the Tevatron beam abort system

    International Nuclear Information System (INIS)

    Kidd, J.; Mokhov, N.; Murphy, T.; Palmer, M.; Toohig, T.; Turkot, F.; VanGinneken, A.

    1981-01-01

    The beam abort system proposed for the Fermilab Tevatron Accelerator will extract the proton beam from the ring in a single turn (approximately 20/mu/s) and direct it to an external beam dump. It is the function of the beam dump to absorb the unwanted beam and limit the escaping radiation to levels that are acceptable to the surrounding populace and apparatus. A beam dump that is expected to meet these requirements has been designed and constructed. Detailed design of the dump, including considerations leading to the choice of materials, are given. 6 refs

  16. Cervical cancer incidence and mortality in Fiji 2003-2009.

    Science.gov (United States)

    Kuehn, Rebecca; Fong, James; Taylor, Richard; Gyaneshwar, Rajanishwar; Carter, Karen

    2012-08-01

    Previous studies indicate that cervical cancer is the second most frequent cancer and most common cause of cancer mortality among women in Fiji. There is little published data on the epidemiology of cervical cancer in Pacific countries. To determine the incidence 2003-2009 of, and mortality 2003-2008 from, cervical cancer by ethnicity and period in Fiji, identify evidence of secular change and relate these data to other Pacific countries, Australia and New Zealand. Counts of incident cervical cancer cases (2003-2009) and unit record mortality data (2003-2008) from the Fiji Ministry of Health were used to calculate age-standardised (to the WHO World Population) cervical cancer incidence and mortality rates, and cervical or uterine cancer mortality rates, by ethnicity, with 95% confidence intervals. On the basis of comparison of cervical cancer mortality with cervical or uterine cancer mortality in Fiji with similar populations, misclassification of cervical cancer deaths is unlikely. There is no evidence of secular change in cervical cancer incidence and mortality rates for the study period. For women of all ages and ethnicities, the age-standardised incidence rate of cervical cancer (2003-2009) was 27.6 per 100,000 (95% CI 25.4-29.8) and the age-standardised mortality rate (2003-2008) was 23.9 per 100,000 (95% CI 21.5-26.4). The mortality/incidence ratio was 87%. Fijians had statistically significant higher age-standardised incidence and mortality rates than Indians. Fiji has one of the highest estimated rates of cervical cancer incidence and mortality in the Pacific region. Cervical cancer screening in Fiji needs to be expanded and strengthened. © 2012 The Authors ANZJOG © 2012 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.

  17. Grazing Incidence Optics Technology

    Science.gov (United States)

    Ramsey, Brian; Smith, W. Scott; Gubarev, Mikhail; McCracken, Jeff

    2015-01-01

    This project is to demonstrate the capability to directly fabricate lightweight, high-resolution, grazing-incidence x-ray optics using a commercially available robotic polishing machine. Typical x-ray optics production at NASA Marshall Space Flight Center (MSFC) uses a replication process in which metal mirrors are electroformed on to figured and polished mandrels from which they are later removed. The attraction of this process is that multiple copies can be made from a single master. The drawback is that the replication process limits the angular resolution that can be attained. By directly fabricating each shell, errors inherent in the replication process are removed. The principal challenge now becomes how to support the mirror shell during all aspects of fabrication, including the necessary metrology to converge on the required mirror performance specifications. This program makes use of a Zeeko seven-axis computer-controlled polishing machine (see fig. 1) and supporting fabrication, metrology, and test equipment at MSFC. The overall development plan calls for proof-of-concept demonstration with relatively thick mirror shells (5-6 mm, fig. 2) which are straightforward to support and then a transition to much thinner shells (2-3 mm), which are an order of magnitude thinner than those used for Chandra. Both glass and metal substrates are being investigated. Currently, a thick glass shell is being figured. This has enabled experience to be gained with programming and operating the polishing machine without worrying about shell distortions or breakage. It has also allowed time for more complex support mechanisms for figuring/ polishing and metrology to be designed for the more challenging thinner shells. These are now in fabrication. Figure 1: Zeeko polishing machine.

  18. Goiania incident case study

    International Nuclear Information System (INIS)

    Petterson, J.S.

    1988-06-01

    The reasons for wanting to document this case study and present the findings are simple. According to USDOE technical risk assessments (and our own initial work on the Hanford socioeconomic study), the likelihood of a major accident involving exposure to radioactive materials in the process of site characterization, construction, operation, and closure of a high-level waste repository is extremely remote. Most would agree, however, that there is a relatively high probability that a minor accident involving radiological contamination will occur sometime during the lifetime of the repository -- for example, during transport, at an MRS site or at the permanent site itself during repacking and deposition. Thus, one of the major concerns of the Yucca Mountain Socioeconomic Study is the potential impact of a relatively minor radiation-related accident. A large number of potential impact of a relatively minor radiation-related accident. A large number of potential accident scenarios have been under consideration (such as a transportation or other surface accident which results in a significant decline in tourism, the number of conventions, or the selection of Nevada as a retirement residence). The results of the work in Goiania make it clear, however, that such a significant shift in established social patterns and trends is not likely to occur as a direct outcome of a single nuclear-related accident (even, perhaps, a relatively major one), but rather, are likely to occur as a result of the enduring social interpretations of such an accident -- that is, as a result of the process of understanding, communicating, and socially sustaining a particular set of associations with respect to the initial incident

  19. 46 CFR 56.30-15 - Expanded or rolled joints.

    Science.gov (United States)

    2010-10-01

    ... design conditions and where adequate provisions are made to prevent separation of the joint. Specific... 46 Shipping 2 2010-10-01 2010-10-01 false Expanded or rolled joints. 56.30-15 Section 56.30-15... APPURTENANCES Selection and Limitations of Piping Joints § 56.30-15 Expanded or rolled joints. (a) Expanded or...

  20. Light Beam Generation

    DEFF Research Database (Denmark)

    2007-01-01

    The invention relates to a method and a system for synthesizing a set of controllable light beams by provision of a system for synthesizing a set of light beams, comprising a spatially modulated light source for generation of electromagnetic radiation with a set of replicas of a predetermined......(x-xs, y-ys), a Fourier transforming lens for Fourier transforming the electromagnetic radiation, a first spatial light modulator for phase shifting the Fourier transformed electromagnetic radiation with the phase -F(u, v) of S*, S* is the complex conjugate of the Fourier transformed symbol s, a Fourier...... transforming lens for Inverse Fourier transforming the spatially modulated radiation, whereby a set of light beams are formed propagating through the inverse Fourier plane (x', y') at desired positions (x's, y's), and a controller for controlling the position of a replica of the symbol, s, for movement...

  1. Is every quasar beamed?

    International Nuclear Information System (INIS)

    Barthel, P.D.

    1989-01-01

    A companion paper (Barthel et al.) reports the discovery of superluminal motion in the core of 4C 34.47, the largest known quasi-stellar radio source. Superluminal motion, the apparent continuity of small- and large-scale one-sided radio jets, and the recently established depolarization asymmetry in luminous quasars find a natural explanation in the effects of relativistic beaming. In the frameworkof of this relativistic beaming model, the available data imply that all radio-loud quasars are beamed toward the earth. Powerful radio galaxies may well form the unbeamed parent population. Radio-quiet QSOs and powerful infrared galaxies can be unified using similar orientation effects. 76 references

  2. Laser Beam Focus Analyser

    DEFF Research Database (Denmark)

    Nielsen, Peter Carøe; Hansen, Hans Nørgaard; Olsen, Flemming Ove

    2007-01-01

    the obtainable features in direct laser machining as well as heat affected zones in welding processes. This paper describes the development of a measuring unit capable of analysing beam shape and diameter of lasers to be used in manufacturing processes. The analyser is based on the principle of a rotating...... mechanical wire being swept through the laser beam at varying Z-heights. The reflected signal is analysed and the resulting beam profile determined. The development comprised the design of a flexible fixture capable of providing both rotation and Z-axis movement, control software including data capture...... and finally data analysis based on the ISO approach. The device was calibrated and tested on commercially available laser systems. It showed good reproducibility. It was the target to be able to measure CW lasers with a power up to 200 W, focused down to spot diameters in the range of 10µm. In order...

  3. Fracture of the delivery balloon shaft during balloon-expandable prosthesis alignment during implantation of an Edwards SAPIEN 3.

    Science.gov (United States)

    Arai, Takahide; Hovasse, Thomas; Chevalier, Bernard

    2018-04-01

    The expandable sheath was designed with a lower profile in order to reduce the incidence of vascular complications of transcatheter aortic valve implantation using transfemoral approach. However, once the prosthesis has crossed the sheath, it could be difficult to retrieve it from the body. This is the first case of successful bail-out in an instance of delivery balloon shaft malfunction subsequent to the crossing of an expandable sheath during implantation of an Edwards SAPIEN 3 prosthesis. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  4. Painful Na-channelopathies: an expanding universe.

    Science.gov (United States)

    Waxman, Stephen G

    2013-07-01

    The universe of painful Na-channelopathies--human disorders caused by mutations in voltage-gated sodium channels--has recently expanded in three dimensions. We now know that mutations of sodium channels cause not only rare genetic 'model disorders' such as inherited erythromelalgia and channelopathy-associated insensitivity to pain but also common painful neuropathies. We have learned that mutations of NaV1.8, as well as mutations of NaV1.7, can cause painful Na-channelopathies. Moreover, recent studies combining atomic level structural models and pharmacogenomics suggest that the goal of genomically guided pain therapy may not be unrealistic. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Ergodic theory of expanding thurston maps

    CERN Document Server

    Li, Zhiqiang

    2017-01-01

    Thurston maps are topological generalizations of postcritically-finite rational maps. This book provides a comprehensive study of ergodic theory of expanding Thurston maps, focusing on the measure of maximal entropy, as well as a more general class of invariant measures, called equilibrium states, and certain weak expansion properties of such maps. In particular, we present equidistribution results for iterated preimages and periodic points with respect to the unique measure of maximal entropy by investigating the number and locations of fixed points. We then use the thermodynamical formalism to establish the existence, uniqueness, and various other properties of the equilibrium state for a Holder continuous potential on the sphere equipped with a visual metric. After studying some weak expansion properties of such maps, we obtain certain large deviation principles for iterated preimages and periodic points under an additional assumption on the critical orbits of the maps. This enables us to obtain general eq...

  6. Expanding Greenland’s Glacial Record

    DEFF Research Database (Denmark)

    Bjørk, Anders Anker

    Mass loss from the Greenland Ice Sheet and adjecent glaciers and ice caps has accelerated within the last decades, and these changes are accurately observed using a variety of different data products. However, the observational era is relatively short offering little insight into past dynamics....... On order to expand the glacial history of Greenland, this thesis explores physical and geological archives for evidence of the glaciers’ past response to climatic variations. Using aerial photographs, the dynamic history of the Greenland Ice Sheet is extended back to 1900 C.E. Glacier changes covering...... the entire 20th century show rapid and widespread responses to climate change. On a longer time-scale is the Holocene history of Helheim Glacier reconstructed using evidence of glacial presence accumulated in lake sediments...

  7. Expanding forensic science through forensic intelligence.

    Science.gov (United States)

    Ribaux, Olivier; Talbot Wright, Benjamin

    2014-12-01

    Research and Development ('R&D') in forensic science currently focuses on innovative technologies improving the efficiency of existing forensic processes, from the detection of marks and traces at the scene, to their presentation in Court. R&D approached from this perspective provides no response to doubts raised by recent criminological studies, which question the effective contribution of forensic science to crime reduction, and to policing in general. Traces (i.e. forensic case data), as remnants of criminal activity are collected and used in various forms of crime monitoring and investigation. The aforementioned doubts therefore need to be addressed by expressing how information is conveyed by traces in these processes. Modelling from this standpoint expands the scope of forensic science and provides new R&D opportunities. Twelve propositions for R&D are stated in order to pave the way. Copyright © 2014 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved.

  8. Expanding Policy Imagination in Political Economy

    DEFF Research Database (Denmark)

    Seabrooke, Leonard

    2006-01-01

    Much of the literature in political economy seeks to capture an essential insight into the evolution of political and economic systems to provide a foundation for policy advice. This article suggests that attempts to nut out the kernels of change often restrict rather than expand policy imagination...... capacity to see political, social, and economic changes that do not conform to conventional theories, as well as distorting our understanding of how the contemporary world works. What policymakers want, more than prediction or recitation of conventional theories, is context to understand how policy can...... be implemented. Historical sociology provides a way to generate information about contextual constellations through two "tonics": intentional rationality and social mechanisms. With the assistance of these tonics, historical sociology widens political economy's policy imagination....

  9. Extremozymes: expanding the limits of biocatalysis.

    Science.gov (United States)

    Adams, M W; Perler, F B; Kelly, R M

    1995-07-01

    The study of enzymes isolated from organisms inhabiting unconventional ecosystems has led to the realization that biocatalysis need not be constrained to mild conditions and can be considered at pH's, temperatures, pressures, ionic and solvent environments long thought to be destructive to biomolecules. Parallel to this, it has been demonstrated that even conventional enzymes will catalyze reactions in solvents other than water. However, the intrinsic basis for biological function under extreme conditions is only starting to be addressed, as are associated applications. This was the focus of a recent NSF/NIST-sponsored workshop on extremozymes. Given the information acquired from the study of extremozymes, modification of enzymes to improve their ranges of stability and activity remains a possibility. Ultimately, by expanding the range of conditions suitable for enzyme function, new opportunities to use biocatalysis will be created.

  10. The Expanded Very Large Array Project

    Science.gov (United States)

    Perley, Rick

    2012-10-01

    The Expanded Very Large Array Project, begun in 2001, is now completed -- on time, on budget, and ``on spec.'' The major goal of the project was to multiply the key observational capabilities of the Very Large Array -- the world's most powerful, versatile, and productive radio telescope -- by a factor of at least an order of magnitude by implementation of modern technologies. The result of the project is an operationally new telescope -- renamed the Jansky Very Large Array -- which is capable of new science unimagined in 1980, when the original VLA was completed. In this talk, I will review the goals of the project, and describe the new capabilities of the Jansky Very Large Array. Already, the array is providing fabulous new insights into the physics of the universe,and I will spend the majority of the time describing examples of new results.

  11. Cosmic strings in an expanding spacetime

    International Nuclear Information System (INIS)

    Stein-Schabes, J.A.; Burd, A.B.

    1987-04-01

    We investigate the stability of a static, infinitely long and straight vacuum string solution under inhomogeneous axisymmetric time-dependent perturbations. We find it to be perturbatively stable. We further extend our work by finding a string solutions in an expanding Universe. The back reaction of the string on the gravitational field has been ignored. The background is assumed to be a Friedman-Robertson-Walker (FRW) cosmology. By numerically integrating the field equations in a radiation and matter dominated models, we discover oscillatory solutions. The possible damping of these oscillations is discussed. For late times the solution becomes identical to the static one studied in the first part of the paper. 19 refs., 8 figs

  12. Ultrasonic velocity measurements in expanded liquid mercury

    International Nuclear Information System (INIS)

    Suzuki, K.; Inutake, M.; Fujiwaka, S.

    1977-10-01

    In this paper we present the first results of the sound velocity measurements in expanded liquid mercury. The measurements were made at temperatures up to 1600 0 C and pressures up to 1700 kg/cm 2 by means of an ultrasonic pulse transmission/echo technique which was newly developed for such high temperature/pressure condition. When the density is larger than 9 g/cm 3 , the observed sound velocity decreases linearly with decreasing density. At densities smaller than 9 g/cm 3 , the linear dependence on the density is no longer observed. The observed sound velocity approaches a minimum near the liquid-gas critical point (rho sub(cr) asymptotically equals 5.5 g/cm 3 ). The existing theories for sound velocity in liquid metals fail to explain the observed results. (auth.)

  13. Roots Air Management System with Integrated Expander

    Energy Technology Data Exchange (ETDEWEB)

    Stretch, Dale [Eaton Corporation, Menomonee Falls, WI (United States); Wright, Brad [Eaton Corporation, Menomonee Falls, WI (United States); Fortini, Matt [Eaton Corporation, Menomonee Falls, WI (United States); Fink, Neal [Ballard Power Systems, Burnaby, BC (Canada); Ramadan, Bassem [Kettering Univ., Flint, MI (United States); Eybergen, William [Eaton Corporation, Menomonee Falls, WI (United States)

    2016-07-06

    PEM fuel cells remain an emerging technology in the vehicle market with several cost and reliability challenges that must be overcome in order to increase market penetration and acceptance. The DOE has identified the lack of a cost effective, reliable, and efficient air supply system that meets the operational requirements of a pressurized PEM 80kW fuel cell as one of the major technological barriers that must be overcome. This project leveraged Roots positive displacement development advancements and demonstrated an efficient and low cost fuel cell air management system. Eaton built upon its P-Series Roots positive displacement design and shifted the peak efficiency making it ideal for use on an 80kW PEM stack. Advantages to this solution include: • Lower speed of the Roots device eliminates complex air bearings present on other systems. • Broad efficiency map of Roots based systems provides an overall higher drive cycle fuel economy. • Core Roots technology has been developed and validated for other transportation applications. Eaton modified their novel R340 Twin Vortices Series (TVS) Roots-type supercharger for this application. The TVS delivers more power and better fuel economy in a smaller package as compared to other supercharger technologies. By properly matching the helix angle with the rotor’s physical aspect ratio, the supercharger’s peak efficiency can be moved to the operating range where it is most beneficial for the application. The compressor was designed to meet the 90 g/s flow at a pressure ratio of 2.5, similar in design to the P-Series 340. A net shape plastic expander housing with integrated motor and compressor was developed to significantly reduce the cost of the system. This integrated design reduced part count by incorporating an overhung expander and motor rotors into the design such that only four bearings and two shafts were utilized.

  14. Interactive Exploration for Continuously Expanding Neuron Databases.

    Science.gov (United States)

    Li, Zhongyu; Metaxas, Dimitris N; Lu, Aidong; Zhang, Shaoting

    2017-02-15

    This paper proposes a novel framework to help biologists explore and analyze neurons based on retrieval of data from neuron morphological databases. In recent years, the continuously expanding neuron databases provide a rich source of information to associate neuronal morphologies with their functional properties. We design a coarse-to-fine framework for efficient and effective data retrieval from large-scale neuron databases. In the coarse-level, for efficiency in large-scale, we employ a binary coding method to compress morphological features into binary codes of tens of bits. Short binary codes allow for real-time similarity searching in Hamming space. Because the neuron databases are continuously expanding, it is inefficient to re-train the binary coding model from scratch when adding new neurons. To solve this problem, we extend binary coding with online updating schemes, which only considers the newly added neurons and update the model on-the-fly, without accessing the whole neuron databases. In the fine-grained level, we introduce domain experts/users in the framework, which can give relevance feedback for the binary coding based retrieval results. This interactive strategy can improve the retrieval performance through re-ranking the above coarse results, where we design a new similarity measure and take the feedback into account. Our framework is validated on more than 17,000 neuron cells, showing promising retrieval accuracy and efficiency. Moreover, we demonstrate its use case in assisting biologists to identify and explore unknown neurons. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Propagation of truncated modified Laguerre-Gaussian beams

    Science.gov (United States)

    Deng, D.; Li, J.; Guo, Q.

    2010-01-01

    By expanding the circ function into a finite sum of complex Gaussian functions and applying the Collins formula, the propagation of hard-edge diffracted modified Laguerre-Gaussian beams (MLGBs) through a paraxial ABCD system is studied, and the approximate closed-form propagation expression of hard-edge diffracted MLGBs is obtained. The transverse intensity distribution of the MLGB carrying finite power can be characterized by a single bright and symmetric ring during propagation when the aperture radius is very large. Starting from the definition of the generalized truncated second-order moments, the beam quality factor of MLGBs through a hard-edged circular aperture is investigated in a cylindrical coordinate system, which turns out to be dependent on the truncated radius and the beam orders.

  16. DART: A simulation code for charged particle beams

    International Nuclear Information System (INIS)

    White, R.C.; Barr, W.L.; Moir, R.W.

    1989-01-01

    This paper presents a recently modified version of the 2-D code, DART, which can simulate the behavior of a beam of charged particles whose trajectories are determined by electric and magnetic fields. This code was originally used to design laboratory-scale and full-scale beam direct converters. Since then, its utility has been expanded to allow more general applications. The simulation includes space charge, secondary electrons, and the ionization of neutral gas. A beam can contain up to nine superimposed beamlets of different energy and species. The calculation of energy conversion efficiency and the method of specifying the electrode geometry are described. Basic procedures for using the code are given, and sample input and output fields are shown. 7 refs., 18 figs

  17. Scattering of linearly polarized Bessel beams by dielectric spheres

    Science.gov (United States)

    Shoorian, Hamed

    2017-09-01

    The scattering of a Linearly Polarized Bessel Beam (LPBB) by an isotropic and homogenous dielectric sphere is investigated. Using analytical relation between the cylindrical and the spherical vector wave functions, all the closed- form analytical expressions, in terms of spherical wave-functions expansions, are derived for the scattered field. It is shown that in the case of conical angle of incident Bessel beam is equal to zero, the Linearly Polarized Bessel Beam becomes a plane wave and its scattering coefficients become the same as the expansion coefficients of plane wave in Mie theory. The transverse Cartesian and spherical components of the electric field, scattered by a sphere are shown in the z-plane for different cases, moreover the intensity of the incident Bessel beam and the effects of its conical angle on the scattered field and the field inside the sphere are investigated. To quantitatively study the scattering phenomenon and the variations of the fields inside and outside of the sphere, the scattering and absorption efficiencies are obtained for the scattering of the linearly-polarized Bessel beam, and are compared with those of the plane wave scattering.

  18. Supersonic molecular beam experiments on surface chemical reactions.

    Science.gov (United States)

    Okada, Michio

    2014-10-01

    The interaction of a molecule and a surface is important in various fields, and in particular in complex systems like biomaterials and their related chemistry. However, the detailed understanding of the elementary steps in the surface chemistry, for example, stereodynamics, is still insufficient even for simple model systems. In this Personal Account, I review our recent studies of chemical reactions on single-crystalline Cu and Si surfaces induced by hyperthermal oxygen molecular beams and by oriented molecular beams, respectively. Studies of oxide formation on Cu induced by hyperthermal molecular beams demonstrate a significant role of the translational energy of the incident molecules. The use of hyperthermal molecular beams enables us to open up new chemical reaction paths specific for the hyperthermal energy region, and to develop new methods for the fabrication of thin films. On the other hand, oriented molecular beams also demonstrate the possibility of understanding surface chemical reactions in detail by varying the orientation of the incident molecules. The steric effects found on Si surfaces hint at new ways of material fabrication on Si surfaces. Controlling the initial conditions of incoming molecules is a powerful tool for finely monitoring the elementary step of the surface chemical reactions and creating new materials on surfaces. Copyright © 2014 The Chemical Society of Japan and Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Consistency checks in beam emission modeling for neutral beam injectors

    International Nuclear Information System (INIS)

    Punyapu, Bharathi; Vattipalle, Prahlad; Sharma, Sanjeev Kumar; Baruah, Ujjwal Kumar; Crowley, Brendan

    2015-01-01

    In positive neutral beam systems, the beam parameters such as ion species fractions, power fractions and beam divergence are routinely measured using Doppler shifted beam emission spectrum. The accuracy with which these parameters are estimated depend on the accuracy of the atomic modeling involved in these estimations. In this work, an effective procedure to check the consistency of the beam emission modeling in neutral beam injectors is proposed. As a first consistency check, at a constant beam voltage and current, the intensity of the beam emission spectrum is measured by varying the pressure in the neutralizer. Then, the scaling of measured intensity of un-shifted (target) and Doppler shifted intensities (projectile) of the beam emission spectrum at these pressure values are studied. If the un-shifted component scales with pressure, then the intensity of this component will be used as a second consistency check on the beam emission modeling. As a further check, the modeled beam fractions and emission cross sections of projectile and target are used to predict the intensity of the un-shifted component and then compared with the value of measured target intensity. An agreement between the predicted and measured target intensities provide the degree of discrepancy in the beam emission modeling. In order to test this methodology, a systematic analysis of Doppler shift spectroscopy data obtained on the JET neutral beam test stand data was carried out

  20. Beam dancer fusion device

    International Nuclear Information System (INIS)

    Maier, H.B.

    1984-01-01

    To accomplish fusion of two or more fusion fuel elements numerous minute spots of energy or laser light are directed to a micro target area, there to be moved or danced about by a precision mechanical controlling apparatus at the source of the laser light or electromagnetic energy beams, so that merging and coinciding patterns of light or energy beams can occur around the area of the fuel atoms or ions. The projecting of these merging patterns may be considered as target searching techniques to locate responsive clusters of fuel elements and to compress such elements into a condition in which fusion may occur. Computerized programming may be used

  1. Diamonds for beam instrumentation

    International Nuclear Information System (INIS)

    Griesmayer, Erich

    2013-01-01

    Diamond is perhaps the most versatile, efficient and radiation tolerant material available for use in beam detectors with a correspondingly wide range of applications in beam instrumentation. Numerous practical applications have demonstrated and exploited the sensitivity of diamond to charged particles, photons and neutrons. In this paper, a brief description of a generic diamond detector is given and the interaction of the CVD diamond detector material with protons, electrons, photons and neutrons is presented. Latest results of the interaction of sCVD diamond with 14 MeV mono-energetic neutrons are shown.

  2. Euroschool on Exotic Beams

    CERN Document Server

    Pfützner, Marek; The Euroschool on Exotic Beams, vol. IV

    2014-01-01

    This is the forth volume in a series of Lecture Notes based on the highly successful Euro Summer School on Exotic Beams. The aim of these notes is to provide a thorough introduction to radioactive ion-beam physics at the level of graduate students and young postdocs starting out in the field. Each volume covers a range of topics from nuclear theory to experiment and applications. Vol I has been published as LNP 651, Vol II has been published as LNP 700, and Vol. III has been published as LNP 764.

  3. The Colliding Beams Sequencer

    International Nuclear Information System (INIS)

    Johnson, D.E.; Johnson, R.P.

    1989-01-01

    The Colliding Beam Sequencer (CBS) is a computer program used to operate the pbar-p Collider by synchronizing the applications programs and simulating the activities of the accelerator operators during filling and storage. The Sequencer acts as a meta-program, running otherwise stand alone applications programs, to do the set-up, beam transfers, acceleration, low beta turn on, and diagnostics for the transfers and storage. The Sequencer and its operational performance will be described along with its special features which include a periodic scheduler and command logger. 14 refs., 3 figs

  4. GTK beam test 2017

    CERN Document Server

    Vostinic, Snezana

    2017-01-01

    The GTK is in operation at NA62 since 2014 and is among the few silicon pixel detectors performing 4D tracking. This summer, a beam test was conducted to study the phenomena determining the detector time resolution. The project described here contributed to the beam test preparation, data taking and data analyses. One of the main goals of the test was to understand the weight field contribution to the detector time resolution. This field is distorting the signal pulse shape at the edge of the pixel. Hence, to study this effect, the position of the hits inside the pixel has to be determined. An external telescope was therefore used for this purpose.

  5. Molecular beam epitaxy

    CERN Document Server

    Pamplin, Brian R

    1980-01-01

    Molecular Beam Epitaxy introduces the reader to the use of molecular beam epitaxy (MBE) in the generation of III-V and IV-VI compounds and alloys and describes the semiconductor and integrated optics reasons for using the technique. Topics covered include semiconductor superlattices by MBE; design considerations for MBE systems; periodic doping structure in gallium arsenide (GaAs); nonstoichiometry and carrier concentration control in MBE of compound semiconductors; and MBE techniques for IV-VI optoelectronic devices. The use of MBE to fabricate integrated optical devices and to study semicond

  6. Grazing incidence optics; Proceedings of the Meeting, Orlando, FL, Apr. 3, 4, 1986

    Science.gov (United States)

    Osantowski, John F. (Editor); Van Speybroeck, Leon (Editor)

    1986-01-01

    Papers are presented on the diffraction-limited performance of grazing incidence optical systems; transverse ray aberrations of Wolter type 1 telescopes; hybrid X-ray telescope systems; surface characterization of grazing incidence optics in the extreme UV and X-ray regions; and the surface roughness properties of synchrotron radiation optics. Topics discussed include the simulation of free-abrasive grinding of grazing incidence mirrors with vertical-honing and flexible blades; mirrors for the Extreme Ultraviolet Explorer; the design and development of conical X-ray imaging mirrors; thermal loading considerations for synchrotron radiation mirrors; and grazing incidence optics for synchrotron radiation insertion-device beams. Consideration is given to the interpretation of glancing incidence scattering measurements; damage processes in short wavelength coated FEL optics; the replication of grain incidence optics; and the assembly and alignment of the Technology Mirror Assembly.

  7. CLIC expands to include the Southern Hemisphere

    CERN Multimedia

    Roberto Cantoni

    2010-01-01

    Australia has recently joined the CLIC collaboration: the enlargement will bring new expertise and resources to the project, and is especially welcome in the wake of CERN budget redistributions following the recent adoption of the Medium Term Plan.   The countries involved in CLIC collaboration With the signing of a Memorandum of Understanding on 26 August 2010, the ACAS network (Australian Collaboration for Accelerator Science) became the 40th member of in the multilateral CLIC collaboration making Australia the 22nd country to join the collaboration. “The new MoU was signed by the ACAS network, which includes the Australian Synchrotron and the University of Melbourne”, explains Jean-Pierre Delahaye, CLIC Study Leader. “Thanks to their expertise, the Australian institutes will contribute greatly to the CLIC damping rings and the two-beam test modules." Institutes from any country wishing to join the CLIC collaboration are invited to assume responsibility o...

  8. Incident-angle dependency found in track formation sensitivity of a plastic nuclear track detector (TD-1)

    International Nuclear Information System (INIS)

    Yasuda, Hiroshi

    1999-01-01

    The present study was done since data are hardly available on the incident-angle dependency of track formation sensitivity (S) of the plastic nuclear track detector. Chips of a TD-1 plate, an antioxidant-doped CR-39 (diethyleglycol-bis-allylcarbonate, HARZLAS, Fukuvi Chem. Ind.), were used as a high-LET radiation detector and were exposed to heavy ion beams of C, Ne, and Si under different incident angles in Heavy Ion Medical Accelerator in Chiba of National Institute of Radiological Sciences. After exposed and etched, the chips were observed with an optical microscope and a program for image analysis to calculate S. The S values calculated were found smaller for the beams having lower incident angles. Thus the estimated LET values from the S-LET relationship for vertical incident beams showed large reduction for low-angle particles. Those potential errors should be quantified and corrected in determination of LET spectra in space. (K.H.)

  9. Real time freeway incident detection.

    Science.gov (United States)

    2014-04-01

    The US Department of Transportation (US-DOT) estimates that over half of all congestion : events are caused by highway incidents rather than by rush-hour traffic in big cities. Real-time : incident detection on freeways is an important part of any mo...

  10. The cooling of particle beams

    International Nuclear Information System (INIS)

    Sessler, A.M.

    1994-10-01

    A review is given of the various methods which can be employed for cooling particle beams. These methods include radiation damping, stimulated radiation damping, ionization cooling, stochastic cooling, electron cooling, laser cooling, and laser cooling with beam coupling. Laser Cooling has provided beams of the lowest temperatures, namely 1 mK, but only for ions and only for the longitudinal temperature. Recent theoretical work has suggested how laser cooling, with the coupling of beam motion, can be used to reduce the ion beam temperature in all three directions. The majority of this paper is devoted to describing laser cooling and laser cooling with beam coupling

  11. [Risk assessment expanded accident insurance for children].

    Science.gov (United States)

    Sittaro, N A

    1998-08-01

    Disability is a well known and tragic event for children. While adults are an established group for specific disability insurance cover, children were often neglected in the past. Although parents, organizations and paediatricans are aware of the risk, children specific incidence rates for disability are hardly available. The only sufficient source for some statistical data are the accident statistics because they represent a substantial group of specific cause related disability for children. Incidence rates for disease related chronic severe impairment or disability in children are either derived by single disease research or actuarial calculation of the German Social Disability Registration. Based on this statistical background, an extended accident insurance for children was introduced in Germany covering both accidents and disabling diseases. The key limitation for all variations of this insurance are exclusion clauses for congential diseases and mental disorders. This insurance requires a new approach in underwriting of the health risks. Because of the substantial number of impaired children, a simple decline of substandard cases are unacceptable. The early experience or medical underwriting shows predominantly health impairments of the following types: allergies, bronchial asthma, ectopic eczema (neurodermitis), disorders of speech and articulation, vision disorders and mental impairments. The suggested solution for underwriting of substandard risks is the predetermination of the possible future maximum degree of disability. The need for underwriting guidelines is supported by the market impact of the new disability cover with thousands of insurance policies issued in the first month after introduction.

  12. Beam-beam effects and generalized luminosity

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, J.E.

    1996-01-01

    The assumption is made that before an NLC is approved, a prototype will be necessary that demonstrates the feasibility of a general purpose linear collider capable of {rvec e}{sup {+-}}{rvec e}{sup {+-}}, {rvec {gamma}}{rvec e} and {rvec {gamma}}{rvec {gamma}} incident channels. At an upgraded SLC, such channels could provide new physics over a range of energies upwards of a few GeV. Effects that limit the luminosity of a GLC are discussed together with their possible mitigations. The expected luminosities in the different channels are then predicted in a consistent way for {radical}s{sub ee} = 0.5 TeV.

  13. Investigation of the flat-beam model of the beam-beam interaction

    Directory of Open Access Journals (Sweden)

    Bjoern S. Schmekel

    2003-10-01

    Full Text Available At the interaction point of a storage ring collider each beam is subject to perturbations due to the electromagnetic field of the counterrotating beam. For flat beams, a well-known approximation models the beam by a current sheet which is uniform in the horizontal plane, restricting the particle motion to the vertical direction. In this classical model a water-bag beam distribution has been used to find working points and beam-beam tune shift parameters which lead to a stable beam distribution. We investigate the stability of a more realistic Gaussian equilibrium distribution. A linearized Vlasov equation written in action-angle variables is used to compute the radial and angular modes of a perturbation in two-dimensional phase space to first order in the displacement from the design trajectory. We find that the radial modes, which are often neglected, can have a stabilizing effect on the beam motion.

  14. In situ micro-focused X-ray beam characterization with a lensless camera using a hybrid pixel detector

    International Nuclear Information System (INIS)

    Kachatkou, Anton; Marchal, Julien; Silfhout, Roelof van

    2014-01-01

    Position and size measurements of a micro-focused X-ray beam, using an X-ray beam imaging device based on a lensless camera that collects radiation scattered from a thin foil placed in the path of the beam at an oblique angle, are reported. Results of studies on micro-focused X-ray beam diagnostics using an X-ray beam imaging (XBI) instrument based on the idea of recording radiation scattered from a thin foil of a low-Z material with a lensless camera are reported. The XBI instrument captures magnified images of the scattering region within the foil as illuminated by the incident beam. These images contain information about beam size, beam position and beam intensity that is extracted during dedicated signal processing steps. In this work the use of the device with beams for which the beam size is significantly smaller than that of a single detector pixel is explored. The performance of the XBI device equipped with a state-of-the-art hybrid pixel X-ray imaging sensor is analysed. Compared with traditional methods such as slit edge or wire scanners, the XBI micro-focused beam characterization is significantly faster and does not interfere with on-going experiments. The challenges associated with measuring micrometre-sized beams are described and ways of optimizing the resolution of beam position and size measurements of the XBI instrument are discussed

  15. Literature review on medical incident command.

    Science.gov (United States)

    Rimstad, Rune; Braut, Geir Sverre

    2015-04-01

    It is not known what constitutes the optimal emergency management system, nor is there a consensus on how effectiveness and efficiency in emergency response should be measured or evaluated. Literature on the role and tasks of commanders in the prehospital emergency services in the setting of mass-casualty incidents has not been summarized and published. This comprehensive literature review addresses some of the needs for future research in emergency management through three research questions: (1) What are the basic assumptions underlying incident command systems (ICSs)? (2) What are the tasks of ambulance and medical commanders in the field? And (3) How can field commanders' performances be measured and assessed? A systematic literature search in MEDLINE, PubMed, PsycINFO, Embase, Cochrane Central Register of Controlled Trials, Cochrane Library, ISI Web of Science, Scopus, International Security & Counter Terrorism Reference Center, Current Controlled Trials, and PROSPERO covering January 1, 1990 through March 1, 2014 was conducted. Reference lists of included literature were hand searched. Included papers were analyzed using Framework synthesis. The literature search identified 6,049 unique records, of which, 76 articles and books where included in qualitative synthesis. Most ICSs are described commonly as hierarchical, bureaucratic, and based on military principles. These assumptions are contested strongly, as is the applicability of such systems. Linking of the chains of command in cooperating agencies is a basic difficulty. Incident command systems are flexible in the sense that the organization may be expanded as needed. Commanders may command by direction, by planning, or by influence. Commanders' tasks may be summarized as: conducting scene assessment, developing an action plan, distributing resources, monitoring operations, and making decisions. There is considerable variation between authors in nomenclature and what tasks are included or highlighted

  16. Noncoaxial Bessel-Gauss beams.

    Science.gov (United States)

    Huang, Chaohong; Zheng, Yishu; Li, Hanqing

    2016-04-01

    We proposed a new family of noncoaxial Gauss-truncated Bessel beams through multiplying conventional symmetrical Bessel beams by a noncoaxial Gauss function. These beams can also be regarded as the exponential-truncated version of Bessel-Gauss beams since they can be transformed into the product of Bessel-Gauss beams and an exponential window function along a certain Cartesian axis. The closed-form solutions of the angular spectra and paraxial propagation of these beams were derived. These beams have asymmetrical intensity distributions and carry the same orbit angular momentum per photon as the corresponding Bessel-Gauss beams. While propagating along the z axis, the mth (m≠0) noncoaxial Bessel-Gauss beams rotate their intensity distributions and the mth-order vortex at the beam center has a transverse shift along the direction perpendicular to the offset axis. Depending on the product of the transverse scalar factor of the Bessel beams and the offset between the Gaussian window function and the center of the Bessel beams, the noncoaxial Bessel-Gauss beams can produce unit vortices with opposite signs in pairs during propagation.

  17. Expanding arch aneurysm causing a "kink" in a Bentall graft and heart failure.

    Science.gov (United States)

    Al-Mohaissen, Maha A; Skarsgard, Peter; Khoo, Clarence; Virani, Sean A; Munt, Brad; Leipsic, Jonathon; Ignaszewski, Andrew

    2012-07-01

    Marfan syndrome is associated with a high incidence of aortic root aneurysm and life-threatening aortic dissection. With the successful use of surgical aortic root replacement, dissection-related mortality has been significantly reduced. We present the case of a patient with Marfan syndrome who presented with heart failure secondary to an unusual graft-related complication 14 years after a Bentall procedure. Investigations revealed a supra-aortic stenosis resulting from a kink in the Bentall graft caused by pressure from an expanding aortic arch aneurysm. The patient underwent surgery with improvement in his ejection fraction and heart failure symptoms.

  18. WORKSHOP: Beam cooling

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    Cooling - the control of unruly particles to provide well-behaved beams - has become a major new tool in accelerator physics. The main approaches of electron cooling pioneered by Gersh Budker at Novosibirsk and stochastic cooling by Simon van der Meer at CERN, are now complemented by additional ideas, such as laser cooling of ions and ionization cooling of muons

  19. Neutrino beam plasma instability

    Indian Academy of Sciences (India)

    Abstract. We derive relativistic fluid set of equations for neutrinos and electrons from relativistic. Vlasov equations with Fermi weak interaction force. Using these fluid equations, we obtain a dis- persion relation describing neutrino beam plasma instability, which is little different from normal dispersion relation of streaming ...

  20. Neutrino beam plasma instability

    Indian Academy of Sciences (India)

    We derive relativistic fluid set of equations for neutrinos and electrons from relativistic Vlasov equations with Fermi weak interaction force. Using these fluid equations, we obtain a dispersion relation describing neutrino beam plasma instability, which is little different from normal dispersion relation of streaming instability.