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Sample records for astronomical beam combiner

  1. UV Written Integrated Optical Beam Combiner for Near Infrared Astronomical Interferometry

    DEFF Research Database (Denmark)

    Svalgaard, Mikael; Olivero, Massimo; Jocou, Laurent

    2006-01-01

    A near infrared integrated optical beam combiner for astronomical interferometry is demonstrated for the first time by direct UV writing. High fringe contrast >95%, low total loss (0.7 dB), low crosstalk and broadband performance is demonstrated....

  2. Coherent laser beam combining

    CERN Document Server

    Brignon, Arnaud

    2013-01-01

    Recently, the improvement of diode pumping in solid state lasers and the development of double clad fiber lasers have allowed to maintain excellent laser beam quality with single mode fibers. However, the fiber output power if often limited below a power damage threshold. Coherent laser beam combining (CLBC) brings a solution to these limitations by identifying the most efficient architectures and allowing for excellent spectral and spatial quality. This knowledge will become critical for the design of the next generation high-power lasers and is of major interest to many industrial, environme

  3. Beam Combination for Sparse Aperture Telescopes Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is for funding to continue development of an alternative beam combiner for Stellar Imager (SI), a 30-aperture, interferometric telescope chosen as one...

  4. Results from ATLAS Calorimeter Combined Test Beam

    CERN Document Server

    Tarrade, F

    2007-01-01

    Beam tests of combinations of ATLAS calorimeters have been performed both for the barrel and end cap parts. During a combined test beam in summer 2004 a slice of the ATLAS barrel detector - including all detector sub systems from the inner tracker, the calorimetry to the muon system - was exposed to particle beams (electrons, pions, photons, muons) with different energies (1GeV to 350GeV). The aim was to study the combined performance of the different detector sub systems in ATLAS-like conditions. We will present the electronics calibration scheme of the electromagnetic calorimeter and its implementation. The following studies on the combined testbeam data have been performed and will be presented: performance of the electromagnetic calorimetry down to very low energies (> GeV), photon reconstruction including converted photons and position measurements using the very precise ATLAS tracker and the electromagnetic calorimeter. These measurements have been compared to Monte Carlo simulations showing the good de...

  5. Measurement of antenna surfaces from in- and out-of-focus beam maps using astronomical sources

    Science.gov (United States)

    Nikolic, B.; Hills, R. E.; Richer, J. S.

    2007-04-01

    We present a technique for the accurate estimation of large-scale errors in an antenna surface using astronomical sources and detectors. The technique requires several out-of-focus images of a compact source and the signal-to-noise ratio needs to be good but not unreasonably high. For a given pattern of surface errors, the expected form of such images can be calculated directly. We show that it is possible to solve the inverse problem of finding the surface errors from the images in a stable manner using standard numerical techniques. To do this we describe the surface error as a linear combination of a suitable set of basis functions (we use Zernike polynomials). We present simulations illustrating the technique and in particular we investigate the effects of receiver noise and pointing errors. Measurements of the 15-m James Clerk Maxwell telescope made using this technique are presented as an example. The key result is that good measurements of errors on large spatial scales can be obtained if the input images have a signal-to-noise ratio of order 100 or more. The important advantage of this technique over transmitter-based holography is that it allows measurements at arbitrary elevation angles, so allowing one to characterise the large scale deformations in an antenna as a function of elevation.

  6. Spectral beam combining of diode lasers with high efficiency

    DEFF Research Database (Denmark)

    Müller, André; Vijayakumar, Deepak; Jensen, Ole Bjarlin

    2012-01-01

    Based on spectral beam combining we obtain 16 W of output power, combining two 1063 nm DBR-tapered diode lasers. The spectral separation within the combined beam can be used for subsequent sum-frequency generation.......Based on spectral beam combining we obtain 16 W of output power, combining two 1063 nm DBR-tapered diode lasers. The spectral separation within the combined beam can be used for subsequent sum-frequency generation....

  7. Direct UV-Written Integrated Optical Beam Combiner for Stellar Interferometry

    DEFF Research Database (Denmark)

    Olivero, Massimo; Svalgaard, Mikael; Jocou, L.

    2007-01-01

    In this paper, we report the fabrication of an optical-beam combiner for stellar interferometry by means of direct ultraviolet (UV) writing. The component is shown to have good performance (fringe contrast > 95%, total loss similar to 0.7, -40-dB crosstalk, broadband operation covering at least...... the range 1.49-1.65 mu m, and low differential chromatic dispersion). The overall performance exceeds that of similar components currently used for astronomical research. This result, combined with the fast-prototyping ability of UV writing, opens up new possibilities for the realization of highly optimized...

  8. Pixel-Tilecal-MDT Combined Test Beam

    CERN Document Server

    B. Di Girolamo

    A test with many expectations When an additional week of running (from September 11th to 18th) was allocated for the test-beam, it was decided to give priority to a combined run with the participation of the Pixel, Tilecal and MDT sub-detectors. The integration of these three sub-detectors was possible as they all use the baseline (DAQ-1/EF based) DAQ for test beams (as reported in a previous e-news). The tests and the addition of a common trigger and busy were organized in a short timescale by experts from the three sub-detectors and DAQ/EF. The expectations were many; both looking for problems and finding solutions. The setup The setup, shown in the figure, consisted of the Pixel telescope normally used during the sub-detector tests, two Tilecal barrel modules, two Tilecal extended barrel modules, and six MDT barrel chambers. This fully occupied a length of some 30 meters in the H8 line of the SPS North Area. Each sub-detector used their own specialized front-end electronics. The data collected by modu...

  9. The 2004 ATLAS Combined Test Beam

    CERN Multimedia

    The ATLAS CTB Team, .

    2004-01-01

    In the year 2004, ATLAS has been involved in a huge combined test beam (CTB) effort in H8. A complete slice of the barrel detector and of the Muon End-cap has been tested, with the following clear goals: pre-commission the final elements and study the detector performance in a realistic combined data taking. Thanks to this experience, a lot of expertise in the operations has been acquired and much data (~ 4.6 TB of data, ~ 90 million events on castor) has been collected and is already under analysis. The CTB has been characterized by different phases with an incremental presence of sub-detectors modules and associated DAQ infrastructure, as well as incremental improvement of analysis tools for prompt data certification. The physics goals of the CTB have been defined in consultation with the physics coordinator, all the sub-detector representatives and the combined performance group representative. With all these indications, a detailed run plan day-by-day schedule was defined before the CTB start and was foll...

  10. Test Beam Coordination: 2003 ATLAS Combined Test Beam

    CERN Multimedia

    Di Girolamo, B.

    The 2003 Test Beam Period The 2003 Test Beam period has been very fruitful for ATLAS. In spite of several days lost because of the accelerator problems, ATLAS has been able to achieve many results: FCAL has completed the calibration program in H6 Tilecal has completed the calibration program in H8 Pixel has performed extensive studies with normal and high intensity beams (up to 1.4*108 hadrons/spill) SCT has completed a variety of studies with quite a high number of modules operated concurrently TRT has performed several studies at high, low and very low energy (first use of the new H8 beam in the range 1 to 9 GeV) Muons (MDT,RPC and TGC) have been operating a large setup for about 5 months. The almost final MDT ROD (MROD) has been integrated in the readout and the final trigger electronics for TGC and RPC has been tested and certified with normal beam and during dedicated 40 MHz beam periods. The TDAQ has exploited a new generation prototype successfully and the new Event Filter infrastructure f...

  11. Coherent and spectral beam combining of fiber lasers

    Science.gov (United States)

    Augst, S. J.; Redmond, S. M.; Yu, C. X.; Ripin, D. J.; Fan, T. Y.; Goodno, G. D.; Thielen, P. A.; Rothenberg, J. E.; Sanchez-Rubio, A.

    2012-02-01

    State-of-the-art diffraction-limited fiber lasers are presently capable of producing kilowatts of power. Power levels produced by single elements are gradually increasing but beam combining techniques are attractive for rapidly scaling fiber laser systems to much higher power levels. We discuss both coherent and spectral beam combining techniques for scaling fiber laser systems to high brightness and high power. Recent results demonstrating beam combination of 500-W commercial fiber laser amplifiers will be presented.

  12. Combined phenomena of beam-beam and beam-electron cloud interactionsin circular e^{+}e^{-} colliders

    Directory of Open Access Journals (Sweden)

    Kazuhito Ohmi

    2002-10-01

    Full Text Available An electron cloud causes various effects in high intensity positron storage rings. The positron beam and the electron cloud can be considered a typical two-stream system with a certain plasma frequency. Beam-beam interaction is another important effect for high luminosity circular colliders. Colliding two beams can be considered as a two-stream system with another plasma frequency. We study the combined phenomena of the beam-electron cloud and beam-beam interactions from a viewpoint of two complex two-stream effects with two plasma frequencies.

  13. Coherent beam combiner for a high power laser

    Science.gov (United States)

    Dane, C. Brent; Hackel, Lloyd A.

    2002-01-01

    A phase conjugate laser mirror employing Brillouin-enhanced four wave mixing allows multiple independent laser apertures to be phase locked producing an array of diffraction-limited beams with no piston phase errors. The beam combiner has application in laser and optical systems requiring high average power, high pulse energy, and low beam divergence. A broad range of applications exist in laser systems for industrial processing, especially in the field of metal surface treatment and laser shot peening.

  14. Beam modulation due to thermal deformation of grating in a spectral beam combining system.

    Science.gov (United States)

    Li, Linxin; Jin, Yunxia; Kong, Fanyu; Wang, Leilei; Chen, Junming; Shao, Jianda

    2017-07-01

    As the power of a spectral beam combining (SBC) system increases, the temperature of the multilayer dielectric grating (MDG) inevitably rises under the influence of high-power continuous-wave (CW) laser irradiation. Hence, thermal deformation of the MDG occurs, along with degeneration of the combined beam properties. In this study, we experimentally and theoretically investigate the influence of the MDG thermal deformation on the combined beam properties. An experimental setup is first proposed, in which beam quality M2, beam profile, and MDG wavefront deformation are investigated. The experimental results indicate that the beam quality clearly degrades and the MDG wavefront deformation becomes more significant with increasing pump-CW power density. On this basis, a calculation model for MDG thermal deformation in SBC systems is proposed. The results indicate that MDG wavefront deformation becomes more significant, combined beam profile becomes deformed, and beam quality of the combined beam degrades with increasing power density. Further, thermal expansion of the substrate is a crucial factor that induces MDG wavefront deformation and far-field intensity modulation.

  15. New beam shaping: Matched filtering combined with GPC

    DEFF Research Database (Denmark)

    Glückstad, Jesper

    2010-01-01

    We adapt concepts frolll matched filtering 10 propose a method for generating rcconligurablc multiple beams. Combined with the Generalized Phase Contrast (GPC) technique, the proposed method coined mGPC can yield dynamically rcconfigurablc optical beam 31rdYS wilh high light efficiency for optical...

  16. Fast Vertical Beam Instability in the CTF3 Combiner Ring

    CERN Document Server

    Corsini, R; Biscari, C; Ghigo, A; Schulte, D; Skowronski, P K; Tecker, F

    2008-01-01

    The CLIC Test Facility CTF3 is being built at CERN by an international collaboration, in order to demonstrate the main feasibility issues of the CLIC two-beam technology by 2010. The facility includes an 84 m combiner ring, which was installed and put into operation in 2007. High-current operation has shown a vertical beam break-up instability, leading to high beam losses over the four turns required for nominal operation of the CTF3 ring. Such instability is most likely due to the vertically polarized transverse mode in the RF deflectors used for beam injection and combination. In this paper we report the experimental data and compare them with simulations. Possible methods to eliminate the instability are also outlined.

  17. Separating and combining single-mode and multimode optical beams

    Science.gov (United States)

    Ruggiero, Anthony J; Masquelier, Donald A; Cooke, Jeffery B; Kallman, Jeffery S

    2013-11-12

    Techniques for combining initially separate single mode and multimode optical beams into a single "Dual Mode" fiber optic have been developed. Bi-directional propagation of two beams that are differentiated only by their mode profiles (i.e., wavefront conditions) is provided. The beams can be different wavelengths and or contain different modulation information but still share a common aperture. This method allows the use of conventional micro optics and hybrid photonic packaging techniques to produce small rugged packages suitable for use in industrial or military environments.

  18. Coherent beam combining architectures for high power tapered laser arrays

    Science.gov (United States)

    Schimmel, G.; Janicot, S.; Hanna, M.; Decker, J.; Crump, P.; Erbert, G.; Witte, U.; Traub, M.; Georges, P.; Lucas-Leclin, G.

    2017-02-01

    Coherent beam combining (CBC) aims at increasing the spatial brightness of lasers. It consists in maintaining a constant phase relationship between different emitters, in order to combine them constructively in one single beam. We have investigated the CBC of an array of five individually-addressable high-power tapered laser diodes at λ = 976 nm, in two architectures: the first one utilizes the self-organization of the lasers in an interferometric extended-cavity, which ensures their mutual coherence; the second one relies on the injection of the emitters by a single-frequency laser diode. In both cases, the coherent combining of the phase-locked beams is ensured on the front side of the array by a transmission diffractive grating with 98% efficiency. The passive phase-locking of the laser bar is obtained up to 5 A (per emitter). An optimization algorithm is implemented to find the proper currents in the five ridge sections that ensured the maximum combined power on the front side. Under these conditions we achieve a maximum combined power of 7.5 W. In the active MOPA configuration, we can increase the currents in the tapered sections up to 6 A and get a combined power of 11.5 W, corresponding to a combining efficiency of 76%. It is limited by the beam quality of the tapered emitters and by fast phase fluctuations between emitters. Still, these results confirm the potential of CBC approaches with tapered lasers to provide a high-power and high-brightness beam, and compare with the current state-of-the-art with laser diodes.

  19. Blind Astronomers

    Science.gov (United States)

    Hockey, Thomas A.

    2011-01-01

    The phrase "blind astronomer” is used as an allegorical oxymoron. However, there were and are blind astronomers. What of famous blind astronomers? First, it must be stated that these astronomers were not martyrs to their craft. It is a myth that astronomers blind themselves by observing the Sun. As early as France's William of Saint-Cloud (circa 1290) astronomers knew that staring at the Sun was ill-advised and avoided it. Galileo Galilei did not invent the astronomical telescope and then proceed to blind himself with one. Galileo observed the Sun near sunrise and sunset or through projection. More than two decades later he became blind, as many septuagenarians do, unrelated to their profession. Even Isaac Newton temporarily blinded himself, staring at the reflection of the Sun when he was a twentysomething. But permanent Sun-induced blindness? No, it did not happen. For instance, it was a stroke that left Scotland's James Gregory (1638-1675) blind. (You will remember the Gregorian telescope.) However, he died days later. Thus, blindness little interfered with his occupation. English Abbot Richard of Wallingford (circa 1291 - circa 1335) wrote astronomical works and designed astronomical instruments. He was also blind in one eye. Yet as he further suffered from leprosy, his blindness seems the lesser of Richard's maladies. Perhaps the most famous professionally active, blind astronomer (or almost blind astronomer) is Dominique-Francois Arago (1786-1853), director until his death of the powerful nineteenth-century Paris Observatory. I will share other _ some poignant _ examples such as: William Campbell, whose blindness drove him to suicide; Leonhard Euler, astronomy's Beethoven, who did nearly half of his life's work while almost totally blind; and Edwin Frost, who "observed” a total solar eclipse while completely sightless.

  20. Common-Mode Spectral Broadening for Coherent Beam Combination (PREPRINT)

    Science.gov (United States)

    2015-04-03

    Common-Mode Spectral Broadening for Coherent Beam Combination Jason E. Langseth,∗ Andrew J. Benedick, Steven J. Augst, Michael S. Riley, and T.Y. Fan...which effectively suppresses SBS in the amplifier yet allows for efficient CBC. The fringe contrast at low and high power was greater than 96%. OCIS...large inten- sity fluctuation caused by the misaligned PRBS phase modulation disappears and clear interference fringes are observed. The SPGD phase

  1. FLUOR fibered beam combiner at the CHARA array

    Science.gov (United States)

    Coudé du Foresto, Vincent; Borde, Pascal J.; Merand, Antoine; Baudouin, Cyrille; Remond, Antonin; Perrin, Guy S.; Ridgway, Stephen T.; ten Brummelaar, Theo A.; McAlister, Harold A.

    2003-02-01

    The fibered beam combiner FLUOR, which has provided high accuracy visibility measurements on the IOTA interferometer, is being moved to the CHARA array which provides five 1m telescopes on baselines ranging from 35 to 330m. The combination CHARA/FLUOR makes it possible for the first time to achieve sub-milliarcsecond resolution in the K band, with a dynamic range of 100 or more. We explore the scientific potential of CHARA/FLUOR, most notably in the domains of high contrast binaries and the characterization of Cepheid pulsations, and present some of the anticipated developements.

  2. Astronomical Cybersketching

    CERN Document Server

    Grego, Peter

    2009-01-01

    Outlines the techniques involved in making observational sketches and more detailed 'scientific' drawings of a wide variety of astronomical subjects using modern digital equipment; primarily PDAs and tablet PCs. This book also discusses about choosing hardware and software

  3. Trigger and DAQ in the Combined Test Beam

    CERN Multimedia

    Dobson, M; Padilla, C

    2004-01-01

    Introduction During the Combined Test Beam the latest prototype of the ATLAS Trigger and DAQ system is being used to support the data taking of all the detectors. Further development of the TDAQ subsystems benefits from the direct experience given by the integration in the beam test. Support of detectors for the Combined Test Beam All ATLAS detectors need their own detector-specific DAQ development. The readout electronics is controlled by a Readout Driver (ROD), custom-built for each detector. The ROD receives data for events that are accepted by the first level trigger. The detector-specific part of the DAQ system needs to control the ROD and to respond to commands of the central DAQ (e.g. to "Start" a run). The ROD module then sends event data to a Readout System (ROS), a PC with special receiver modules/buffers. At this point the data enters the realm of the ATLAS DAQ and High Level Trigger system, constructed from Linux PCs connected with gigabit Ethernet networks. Most ATLAS detectors, representing s...

  4. Three beam-combining schemes in a color projection display

    Science.gov (United States)

    Scholl, Marija S.

    1987-01-01

    Several beam-combining schemes for on-axis and off-axis optical system layout are presented. The on-axis approaches include two crossed plates with dichroic coatings placed at 90 deg, with respect to each other, and a pentaprism arrangement. The off-axis layout of the cathode ray tubes requires that the images be combined at the display screen. These image-combining approaches are compared for the standard television rates of 525 lines and the high-resolution television at 1200/2000 lines under development in Japan. It is concluded that, for the high-performance, high-color fidelity, and high-resolution projection systems, which are expected to fit into a small volume of space such as a Space Station display or a cockpit panoramic display, a folded configuration with either crossed plates or pentaprism plates will result in an optimum color display.

  5. Combined electron beam and UV lithography in SU-8

    DEFF Research Database (Denmark)

    Gersborg-Hansen, Morten; Thamdrup, Lasse Højlund; Mironov, Andrej

    2007-01-01

    We present combined electron beam and UV lithography (CEUL) in SU-8 as a fast and flexible lithographic technique for prototyping of functional polymer devices and pattern transfer applications. CEUL is a lithographic technique suitable for defining both micrometer and nanometer scale features...... in a single polymer film on the wafer scale. The height of the micrometer and nanometer scale features is matched within 30 nm. As a pattern transfer application, we demonstrate stamp fabrication and thermal nanoimprint of a 2-dimensional array of 100 nm wide lines with a pitch of 380 nm in connection...

  6. The SPEDE Spectrometer: Combined In-Beam γ-ray and Conversion Electron Spectroscopy with Radioactive Ion Beams

    Science.gov (United States)

    Papadakis, Philippos; Pakarinen, Janne; Butler, Peter A.; Cox, Daniel M.; Davies, Paul; Greenlees, Paul; Herzberg, Rolf-Dietmar; Huyse, Mark; Jenkins, David G.; Konki, Joonas; O'Neill, George G.; Rahkila, Panu; Ranttila, Kimmo; Saarela, Ville-Peka; Thornhill, Jim; Van Duppen, Piet; Wells, David

    The SPEDE conversion electron spectrometer will be combined with the Miniball germanium detector array for combined in-beam electron and γ-ray spectroscopy with radioactive ion beams. SPEDE will be primarily employed in Coulomb excitation experiments at HIE-ISOLDE, CERN.

  7. Novel adaptive fiber-optics collimator for coherent beam combination.

    Science.gov (United States)

    Zhi, Dong; Ma, Pengfei; Ma, Yanxing; Wang, Xiaolin; Zhou, Pu; Si, Lei

    2014-12-15

    In this manuscript, we experimentally validate a novel design of adaptive fiber-optics collimator (AFOC), which utilizes two levers to enlarge the movable range of the fiber end cap. The enlargement of the range makes the new AFOC possible to compensate the end-cap/tilt aberration in fiber laser beam combining system. The new AFOC based on flexible hinges and levers was fabricated and the performance of the new AFOC was tested carefully, including its control range, frequency response and control accuracy. Coherent beam combination (CBC) of two 5-W fiber amplifiers array with simultaneously end-cap/tilt control and phase-locking control was implemented successfully with the novel AFOC. Experimental results show that the average normalized power in the bucket (PIB) value increases from 0.311 to 0.934 with active phasing and tilt aberration compensation simultaneously, and with both controls on, the fringe contrast improves to more than 82% from 0% for the case with both control off. This work presents a promising structure for tilt aberration control in high power CBC system.

  8. Beam splitter and combiner based on Bloch oscillations in spatially modulated waveguide arrays

    CERN Document Server

    Zhang, Yiqi; Zhong, Weiping; Wen, Feng; Guo, Yang; Guo, Yao; Lu, Keqing; Zhang, Yanpeng

    2014-01-01

    We numerically investigate the light beam propagation in periodic waveguide arrays which are elaborately modulated with certain structures. We find that the light beam may split, coalesce, deflect, and be localized during propagation in these spatially modulated waveguide arrays. All the phenomena originate from Bloch oscillations, and supply possible method for fabricating on-chip beam splitters and beam combiners.

  9. Astronomical Ecosystems

    Science.gov (United States)

    Neuenschwander, D. E.; Finkenbinder, L. R.

    2004-05-01

    Just as quetzals and jaguars require specific ecological habitats to survive, so too must planets occupy a tightly constrained astronomical habitat to support life as we know it. With this theme in mind we relate the transferable features of our elementary astronomy course, "The Astronomical Basis of Life on Earth." Over the last five years, in a team-taught course that features a spring break field trip to Costa Rica, we have introduced astronomy through "astronomical ecosystems," emphasizing astronomical constraints on the prospects for life on Earth. Life requires energy, chemical elements, and long timescales, and we emphasize how cosmological, astrophysical, and geological realities, through stabilities and catastrophes, create and eliminate niches for biological life. The linkage between astronomy and biology gets immediate and personal: for example, studies in solar energy production are followed by hikes in the forest to examine the light-gathering strategies of photosynthetic organisms; a lesson on tides is conducted while standing up to our necks in one on a Pacific beach. Further linkages between astronomy and the human timescale concerns of biological diversity, cultural diversity, and environmental sustainability are natural and direct. Our experience of teaching "astronomy as habitat" strongly influences our "Astronomy 101" course in Oklahoma as well. This "inverted astrobiology" seems to transform our student's outlook, from the universe being something "out there" into something "we're in!" We thank the SNU Science Alumni support group "The Catalysts," and the SNU Quetzal Education and Research Center, San Gerardo de Dota, Costa Rica, for their support.

  10. A survey of beam-combining technologies for laser space power transmission

    Science.gov (United States)

    Kwon, J. H.; Williams, M. D.; Lee, J. H.

    1988-01-01

    The combination of laser beams holds much promise for obtaining powerful beams. Methods are surveyed for beam combination (coherent and incoherent) and two of them are identified as the most effective means for achieving high power transmission in space. The two methods as applied to laser diode arrays are analyzed, and potentially productive work areas for the advancement of technology are delineated.

  11. Integrated optics prototype beam combiner for long baseline interferometry in the L and M bands

    Science.gov (United States)

    Tepper, J.; Labadie, L.; Diener, R.; Minardi, S.; Pott, J.-U.; Thomson, R.; Nolte, S.

    2017-06-01

    Context. Optical long baseline interferometry is a unique way to study astronomical objects at milli-arcsecond resolutions not attainable with current single-dish telescopes. Yet, the significance of its scientfic return strongly depends on a dense coverage of the uv-plane and a highly stable transfer function of the interferometric instrument. In the last few years, integrated optics (IO) beam combiners have facilitated the emergence of 4-telescope interferometers such as PIONIER or GRAVITY, boosting the imaging capabilities of the VLTI. However, the spectral range beyond 2.2 μm is not ideally covered by the conventional silica based IO. Here, we consider new laser-written IO prototypes made of gallium lanthanum sulfide (GLS) glass, a material that permits access to the mid-infrared spectral regime. Aims: Our goal is to conduct a full characterization of our mid-IR IO two-telescope coupler in order to measure the performance levels directly relevant for long-baseline interferometry. We focus in particular on the exploitation of the L and M astronomical bands. Methods: We use a dedicated Michelson-interferometer setup to perform Fourier transform spectroscopy on the coupler and measure its broadband interferometric performance. We also analyze the polarization properties of the coupler, the differential dispersion and phase degradation, as well as the modal behavior and the total throughput. Results: We measure broadband interferometric contrasts of 94.9% and 92.1% for unpolarized light in the L and M bands. Spectrally integrated splitting ratios are close to 50%, but show chromatic dependence over the considered bandwidths. Additionally, the phase variation due to the combiner is measured and does not exceed 0.04 rad and 0.07 rad across the L and M band, respectively. The total throughput of the coupler including Fresnel and injection losses from free-space is 25.4%. Furthermore, differential birefringence is low (technological solution with promising performance

  12. Combined performance studies for electrons at the 2004 ATLAS combined test-beam

    Science.gov (United States)

    Abat, E.; Abdallah, J. M.; Addy, T. N.; Adragna, P.; Aharrouche, M.; Ahmad, A.; Akesson, T. P. A.; Aleksa, M.; Alexa, C.; Anderson, K.; Andreazza, A.; Anghinolfi, F.; Antonaki, A.; Arabidze, G.; Arik, E.; Atkinson, T.; Baines, J.; Baker, O. K.; Banfi, D.; Baron, S.; Barr, A. J.; Beccherle, R.; Beck, H. P.; Belhorma, B.; Bell, P. J.; Benchekroun, D.; Benjamin, D. P.; Benslama, K.; Bergeaas Kuutmann, E.; Bernabeu, J.; Bertelsen, H.; Binet, S.; Biscarat, C.; Boldea, V.; Bondarenko, V. G.; Boonekamp, M.; Bosman, M.; Bourdarios, C.; Broklova, Z.; Burckhart Chromek, D.; Bychkov, V.; Callahan, J.; Calvet, D.; Canneri, M.; Capeáns Garrido, M.; Caprini, M.; Cardiel Sas, L.; Carli, T.; Carminati, L.; Carvalho, J.; Cascella, M.; Castillo, M. V.; Catinaccio, A.; Cauz, D.; Cavalli, D.; Cavalli Sforza, M.; Cavasinni, V.; Cetin, S. A.; Chen, H.; Cherkaoui, R.; Chevalier, L.; Chevallier, F.; Chouridou, S.; Ciobotaru, M.; Citterio, M.; Clark, A.; Cleland, B.; Cobal, M.; Cogneras, E.; Conde Muino, P.; Consonni, M.; Constantinescu, S.; Cornelissen, T.; Correard, S.; Corso Radu, A.; Costa, G.; Costa, M. J.; Costanzo, D.; Cuneo, S.; Cwetanski, P.; Da Silva, D.; Dam, M.; Dameri, M.; Danielsson, H. O.; Dannheim, D.; Darbo, G.; Davidek, T.; De, K.; Defay, P. O.; Dekhissi, B.; Del Peso, J.; Del Prete, T.; Delmastro, M.; Derue, F.; Di Ciaccio, L.; Di Girolamo, B.; Dita, S.; Dittus, F.; Djama, F.; Djobava, T.; Dobos, D.; Dobson, M.; Dolgoshein, B. A.; Dotti, A.; Drake, G.; Drasal, Z.; Dressnandt, N.; Driouchi, C.; Drohan, J.; Ebenstein, W. L.; Eerola, P.; Efthymiopoulos, I.; Egorov, K.; Eifert, T. F.; Einsweiler, K.; El Kacimi, M.; Elsing, M.; Emelyanov, D.; Escobar, C.; Etienvre, A. I.; Fabich, A.; Facius, K.; Fakhr-Edine, A. I.; Fanti, M.; Farbin, A.; Farthouat, P.; Fassouliotis, D.; Fayard, L.; Febbraro, R.; Fedin, O. L.; Fenyuk, A.; Fergusson, D.; Ferrari, P.; Ferrari, R.; Ferreira, B. C.; Ferrer, A.; Ferrere, D.; Filippini, G.; Flick, T.; Fournier, D.; Francavilla, P.; Francis, D.; Froeschl, R.; Froidevaux, D.; Fullana, E.; Gadomski, S.; Gagliardi, G.; Gagnon, P.; Gallas, M.; Gallop, B. J.; Gameiro, S.; Gan, K. K.; Garcia, R.; Garcia, C.; Gavrilenko, I. L.; Gemme, C.; Gerlach, P.; Ghodbane, N.; Giakoumopoulou, V.; Giangiobbe, V.; Giokaris, N.; Glonti, G.; Goettfert, T.; Golling, T.; Gollub, N.; Gomes, A.; Gomez, M. D.; Gonzalez-Sevilla, S.; Goodrick, M. J.; Gorfine, G.; Gorini, B.; Goujdami, D.; Grahn, K.-J.; Grenier, P.; Grigalashvili, N.; Grishkevich, Y.; Grosse-Knetter, J.; Gruwe, M.; Guicheney, C.; Gupta, A.; Haeberli, C.; Haertel, R.; Hajduk, Z.; Hakobyan, H.; Hance, M.; Hansen, J. D.; Hansen, P. H.; Hara, K.; Harvey, A., Jr.; Hawkings, R. J.; Heinemann, F. E. W.; Henriques Correia, A.; Henss, T.; Hervas, L.; Higon, E.; Hill, J. C.; Hoffman, J.; Hostachy, J. Y.; Hruska, I.; Hubaut, F.; Huegging, F.; Hulsbergen, W.; Hurwitz, M.; Iconomidou-Fayard, L.; Jansen, E.; Jen-La Plante, I.; Johansson, P. D. C.; Jon-And, K.; Joos, M.; Jorgensen, S.; Joseph, J.; Kaczmarska, A.; Kado, M.; Karyukhin, A.; Kataoka, M.; Kayumov, F.; Kazarov, A.; Keener, P. T.; Kekelidze, G. D.; Kerschen, N.; Kersten, S.; Khomich, A.; Khoriauli, G.; Khramov, E.; Khristachev, A.; Khubua, J.; Kittelmann, T. H.; Klingenberg, R.; Klinkby, E. B.; Kodys, P.; Koffas, T.; Kolos, S.; Konovalov, S. P.; Konstantinidis, N.; Kopikov, S.; Korolkov, I.; Kostyukhin, V.; Kovalenko, S.; Kowalski, T. Z.; Krüger, K.; Kramarenko, V.; Kudin, L. G.; Kulchitsky, Y.; Lacasta, C.; Lafaye, R.; Laforge, B.; Lampl, W.; Lanni, F.; Laplace, S.; Lari, T.; Le Bihan, A.-C.; Lechowski, M.; Ledroit-Guillon, F.; Lehmann, G.; Leitner, R.; Lelas, D.; Lester, C. G.; Liang, Z.; Lichard, P.; Liebig, W.; Lipniacka, A.; Lokajicek, M.; Louchard, L.; Lourerio, K. F.; Lucotte, A.; Luehring, F.; Lund-Jensen, B.; Lundberg, B.; Ma, H.; Mackeprang, R.; Maio, A.; Maleev, V. P.; Malek, F.; Mandelli, L.; Maneira, J.; Mangin-Brinet, M.; Manousakis, A.; Mapelli, L.; Marques, C.; Garcia, S. Marti i.; Martin, F.; Mathes, M.; Mazzanti, M.; McFarlane, K. W.; McPherson, R.; Mchedlidze, G.; Mehlhase, S.; Meirosu, C.; Meng, Z.; Meroni, C.; Mialkovski, V.; Mikulec, B.; Milstead, D.; Minashvili, I.; Mindur, B.; Mitsou, V. A.; Moed, S.; Monnier, E.; Moorhead, G.; Morettini, P.; Morozov, S. V.; Mosidze, M.; Mouraviev, S. V.; Moyse, E. W. J.; Munar, A.; Myagkov, A.; Nadtochi, A. V.; Nakamura, K.; Nechaeva, P.; Negri, A.; Nemecek, S.; Nessi, M.; Nesterov, S. Y.; Newcomer, F. M.; Nikitine, I.; Nikolaev, K.; Nikolic-Audit, I.; Ogren, H.; Oh, S. H.; Oleshko, S. B.; Olszowska, J.; Onofre, A.; Padilla Aranda, C.; Paganis, S.; Pallin, D.; Pantea, D.; Paolone, V.; Parodi, F.; Parsons, J.; Parzhitskiy, S.; Pasqualucci, E.; Passmored, S. M.; Pater, J.; Patrichev, S.; Peez, M.; Perez Reale, V.; Perini, L.; Peshekhonov, V. D.; Petersen, J.; Petersen, T. C.; Petti, R.; Phillips, P. W.; Pina, J.; Pinto, B.; Podlyski, F.; Poggioli, L.; Poppleton, A.; Poveda, J.; Pralavorio, P.; Pribyl, L.; Price, M. J.; Prieur, D.; Puigdengoles, C.; Puzo, P.; RØhne, O.; Ragusa, F.; Rajagopalan, S.; Reeves, K.; Reisinger, I.; Rembser, C.; Bruckman de Renstrom, P. A.; Reznicek, P.; Ridel, M.; Risso, P.; Riu, I.; Robinson, D.; Roda, C.; Roe, S.; Rohne, O.; Romaniouk, A.; Rousseau, D.; Rozanov, A.; Ruiz, A.; Rusakovich, N.; Rust, D.; Ryabov, Y. F.; Ryjov, V.; Salto, O.; Salvachua, B.; Salzburger, A.; Sandaker, H.; Santamarina Rios, C.; Santi, L.; Santoni, C.; Saraiva, J. G.; Sarri, F.; Sauvage, G.; Says, L. P.; Schaefer, M.; Schegelsky, V. A.; Schiavi, C.; Schieck, J.; Schlager, G.; Schlereth, J.; Schmitt, C.; Schultes, J.; Schwemling, P.; Schwindling, J.; Seixas, J. M.; Seliverstov, D. M.; Serin, L.; Sfyrla, A.; Shalanda, N.; Shaw, C.; Shin, T.; Shmeleva, A.; Silva, J.; Simion, S.; Simonyan, M.; Sloper, J. E.; Smirnov, S. Yu; Smirnova, L.; Solans, C.; Solodkov, A.; Solovianov, O.; Soloviev, I.; Sosnovtsev, V. V.; Spanò, F.; Speckmayer, P.; Stancu, S.; Stanek, R.; Starchenko, E.; Straessner, A.; Suchkov, S. I.; Suk, M.; Szczygiel, R.; Tarrade, F.; Tartarelli, F.; Tas, P.; Tayalati, Y.; Tegenfeldt, F.; Teuscher, R.; Thioye, M.; Tikhomirov, V. O.; Timmermans, C. J. W. P.; Tisserant, S.; Toczek, B.; Tremblet, L.; Troncon, C.; Tsiareshka, P.; Tyndel, M.; Karagoez Unel, M.; Unal, G.; Unel, G.; Usai, G.; Van Berg, R.; Valero, A.; Valkar, S.; Valls, J. A.; Vandelli, W.; Vannucci, F.; Vartapetian, A.; Vassilakopoulos, V. I.; Vasilyeva, L.; Vazeille, F.; Vernocchi, F.; Vetter-Cole, Y.; Vichou, I.; Vinogradov, V.; Virzi, J.; Vivarelli, I.; de Vivie, J. B.; Volpi, M.; Anh, T. Vu; Wang, C.; Warren, M.; Weber, J.; Weber, M.; Weidberg, A. R.; Weingarten, J.; Wells, P. S.; Werner, P.; Wheeler, S.; Wiessmann, M.; Wilkens, H.; Williams, H. H.; Wingerter-Seez, I.; Yasu, Y.; Zaitsev, A.; Zenin, A.; Zenis, T.; Zenonos, Z.; Zhang, H.; Zhelezko, A.; Zhou, N.

    2010-11-01

    In 2004 at the ATLAS (A Toroidal LHC ApparatuS) combined test beam, one slice of the ATLAS barrel detector (including an Inner Detector set-up and the Liquid Argon calorimeter) was exposed to particles from the H8 SPS beam line at CERN. It was the first occasion to test the combined electron performance of ATLAS. This paper presents results obtained for the momentum measurement p with the Inner Detector and for the performance of the electron measurement with the LAr calorimeter (energy E linearity and resolution) in the presence of a magnetic field in the Inner Detector for momenta ranging from 20 GeV/c to 100 GeV/c. Furthermore the particle identification capabilities of the Transition Radiation Tracker, Bremsstrahlungs-recovery algorithms relying on the LAr calorimeter and results obtained for the E/p ratio and a way how to extract scale parameters will be discussed.

  13. Improving external beam radiotherapy by combination with internal irradiation.

    Science.gov (United States)

    Dietrich, A; Koi, L; Zöphel, K; Sihver, W; Kotzerke, J; Baumann, M; Krause, M

    2015-07-01

    The efficacy of external beam radiotherapy (EBRT) is dose dependent, but the dose that can be applied to solid tumour lesions is limited by the sensitivity of the surrounding tissue. The combination of EBRT with systemically applied radioimmunotherapy (RIT) is a promising approach to increase efficacy of radiotherapy. Toxicities of both treatment modalities of this combination of internal and external radiotherapy (CIERT) are not additive, as different organs at risk are in target. However, advantages of both single treatments are combined, for example, precise high dose delivery to the bulk tumour via standard EBRT, which can be increased by addition of RIT, and potential targeting of micrometastases by RIT. Eventually, theragnostic radionuclide pairs can be used to predict uptake of the radiotherapeutic drug prior to and during therapy and find individual patients who may benefit from this treatment. This review aims to highlight the outcome of pre-clinical studies on CIERT and resultant questions for translation into the clinic. Few clinical data are available until now and reasons as well as challenges for clinical implementation are discussed.

  14. A combined nulling and imaging pupil-plane beam-combiner for DARWIN

    Science.gov (United States)

    Haaksman, Ron P. H.; de Vries, Cor P.; den Herder, Jan-Willem; Vosteen, L. L. A.; Bokhove, Henk; Mieremet, Arjan L.

    2006-06-01

    The primary goal of DARWIN is to detect earth-like extrasolar planets and to search for biomarkers. This is achieved by means of nulling interferometry, using three free-flying telescopes and a Beam-Combiner (BC) hub. DARWIN will be able to perform astrophysical imaging with high spectral and spatial resolution. Should one of Darwin's telescope flyers fail, then Darwin's capability of detecting earth-sized exo-planets is dramatically reduced. However, with only two telescopes the imaging mode can continue operating with minimal performance degradation, thus ensuring mission success. This work describes a trade-off study between four conceptual three-beam BC's, that are capable of performing both as a nuller and as an imager. A proposed breadboard design will demonstrate end-to-end Fringe-Tracking (FT) and Optical Path-Length (OPL) control. The BC concept is based on a pupil-plane (Michelson) beam combination scheme. Pupil-plane imaging BC's offer a large overlap in terms of optical layout with the nulling BC concept, making it possible to develop a combined nulling- and imaging BC. This means that a reduced number of optical components can be used compared to a scheme with separate BC's. The BC concept inherently compensates for unequal OPL's, which in ground-based interferometers is compensated for by long stroke Optical Delay Lines (ODL's).

  15. Astronomical optics

    CERN Document Server

    Schroeder, Daniel J

    1988-01-01

    Written by a recognized expert in the field, this clearly presented, well-illustrated book provides both advanced level students and professionals with an authoritative, thorough presentation of the characteristics, including advantages and limitations, of telescopes and spectrographic instruments used by astronomers of today.Key Features* Written by a recognized expert in the field* Provides both advanced level students and professionals with an authoritative, thorough presentation of the characteristics, including advantages and limitations, of telescopes and spectrographic i

  16. External-cavity beam combining of 4-channel quantum cascade lasers

    Science.gov (United States)

    Zhao, Yue; Zhang, Jin-Chuan; Zhou, Yu-Hong; Jia, Zhi-Wei; Zhuo, Ning; Zhai, Shen-Qiang; Wang, Li-Jun; Liu, Jun-Qi; Liu, Shu-Man; Liu, Feng-Qi; Wang, Zhan-Guo

    2017-09-01

    We demonstrate an external-cavity (EC) beam combining of 4-channel quantum cascade lasers (QCLs) with an output coupler which makes different QCL beams propagating coaxially. A beam combining efficiency of 35% (up to 75% near threshold) is obtained with a beam quality M2 of 5.5. A peak power of 0.64 W is achieved at a wavelength of 4.7 μm. The differences of spot characteristic between coupled and uncoupled are also showed in this letter. The QCLs in this EC system do not have heat crosstalk so that the system can be used for high power beam combining of QCLs.

  17. The combination of external beam radiotherapy and experimental radioimmunotargeting with a monoclonal anticytokeratin antibody

    National Research Council Canada - National Science Library

    Johansson, Amanda; Eriksson, David; Ullén, Anders; Löfroth, Per‐Olov; Johansson, Lennart; Riklund‐Åhlström, Katrine; Stigbrand, Torgny

    2002-01-01

    .... The purpose of this study was to detect potential benefits with different treatment timing strategies when combining external beam radiotherapy and radioimmunotargeting, with the anticytokeratin monoclonal antibody (MAb...

  18. Combined external beam and intraluminal radiotherapy for irresectable Klatskin tumors

    Energy Technology Data Exchange (ETDEWEB)

    Schleicher, U.M. [Klinik fuer Strahlentherapie, Technische Hochschule Aachen (Germany); Staatz, G. [Klinik fuer Radiologische Diagnostik, Technische Hochschule Aachen (Germany); Alzen, G. [Klinik fuer Radiologische Diagnostik, Technische Hochschule Aachen (Germany); Abt. Kinderradiologie, Giessen Univ. (Germany); Andreopoulos, D. [Klinik fuer Strahlentherapie, Technische Hochschule Aachen (Germany); BOC Oncology Centre, Nikosia (Cyprus)

    2002-12-01

    Background: In most cases of proximal cholangiocarcinoma, curative surgery is not possible. Radiotherapy can be used for palliative treatment. We report our experience with combined external beam and intraluminal radiotherapy of advanced Klatskin's tumors. Patients and Methods: 30 patients were treated for extrahepatic proximal bile duct cancer. Our schedule consisted for external beam radiotherapy (median dose 30 Gy) and a high-dose-rate brachytherapy boost (median dose 40 Gy) delivered in four or five fractions, which could be applied completely in twelve of our patients. 15 patients in the brachytherapy and nine patients in the non-brachytherapy group received additional low-dose chemotherapy with 5-fluorouracil. Results: The brachytherapy boost dose improved the effect of external beam radiotherapy by increasing survival from a median of 3.9 months in the non-brachytherapy group to 9.1 months in the brachytherapy group. The effect was obvious in patients receiving a brachytherapy dose above 30 Gy, and in those without jaundice at the beginning of radiotherapy (p<0.05). Conclusions: The poor prognosis in patients with advanced Klatskin's tumors may be improved by combination therapy, with the role of brachytherapy and chemotherapy still to be defined. Our results suggest that patients without jaundice should be offered brachytherapy, and that a full dose of more than 30 Gy should be applied. (orig.) [German] Hintergrund: Bei den meisten Patienten mit proximalen Cholangiokarzinomen ist eine kurative Operation nicht mehr moeglich. Im Rahmen der Palliativbehandlung kann die Strahlentherapie eingesetzt werden. Wir berichten ueber unsere Erfahrungen mit der Kombination aus perkutaner und intraluminaler Strahlentherapie fortgeschrittener Klatskin-Tumoren. Patienten und Methode: 30 Patienten wurden wegen extrahepatischer proximaler Gallengangskarzinome behandelt. Unser Therapieschema umfasste eine perkutane Strahlentherapie (mediane Dosis: 30 Gy) sowie einen

  19. Combining freeform-shaped holographic grating and curved detectors in a scheme of multi-slit astronomic spectrograph

    Science.gov (United States)

    Muslimov, Eduard R.; Hugot, Emmanuel; Ferrari, Marc

    2017-05-01

    In the present work we consider optical design of a multi-slit astronomic spectrograph for UV domain with freeform reflective elements. The scheme consists of only two reflective elements - a holographic grating imposed on freeform surface and a freeform mirror. The freeforms are described by standard Zernike polynomials and the hologram is recorded by two coherent point sources. We demonstrate that in such a scheme it's possible to obtain quite high optical quality for an extended field of view and relatively high dispersion on a curved image surface. The spectrograph works with linear field of view of 76x32 mm and provides reciprocal linear dispersion equal to 0.5 nm/mm and typical resolving power of 15 000 over the UV range of 100-200 nm. Feasibility of the optical components is discussed and coupling of the spectrograph with a TMA telescope is demonstrated.

  20. Deflection and Supporting Force Analysis of a Slender Beam under Combined Transverse and Tensile Axial Loads

    Science.gov (United States)

    2016-05-01

    UNCLASSIFIED UNCLASSIFIED Deflection and Supporting Force Analysis of a Slender Beam under Combined Transverse and Tensile Axial Loads Witold...Bernoulli beam theory, and a closed-form expression for the beam deflection as a function of the axial tension force is provided. The analytical solution...was checked by performing a separate nonlinear finite element analysis using beam elements. The value of the peak deflection and its position along

  1. Theory of using magnetic deflections to combine charged particle beams

    Energy Technology Data Exchange (ETDEWEB)

    Steckbeck, Mackenzie K. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Doyle, Barney Lee [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-09-01

    Several radiation effects projects in the Ion Beam Lab (IBL) have recently required two disparate charged particle beams to simultaneously strike a single sample through a single port of the target chamber. Because these beams have vastly different mass–energy products (MEP), the low-MEP beam requires a large angle of deflection toward the sample by a bending electromagnet. A second electromagnet located further upstream provides a means to compensate for the small angle deflection experienced by the high-MEP beam during its path through the bending magnet. This paper derives the equations used to select the magnetic fields required by these two magnets to achieve uniting both beams at the target sample. A simple result was obtained when the separation of the two magnets was equivalent to the distance from the bending magnet to the sample, and the equation is given by: Bs= 1/2(rc/rs) Bc, where Bs and Bc are the magnetic fields in the steering and bending magnet and rc/rs is the ratio of the radii of the bending magnet to that of the steering magnet. This result is not dependent upon the parameters of the high MEP beam, i.e. energy, mass, charge state. Therefore, once the field of the bending magnet is set for the low-MEP beam, and the field in the steering magnet is set as indicted in the equation, the trajectory path of any high-MEP beam will be directed into the sample.

  2. Free-Space Nonlinear Beam Combining Towards Filamentation

    CERN Document Server

    Rostami, Shermineh; Kepler, Daniel; Baudelet, Matthieu; Litchinitser, Natalia M; Richardson, Martin

    2016-01-01

    Multi-filamentation opens new degrees of freedom for manipulating electromagnetic waves in air. However, without control, multiple filament interactions, including attraction, repulsion or fusion often result in formation of complex disordered filament distributions. Moreover, high power beams conventionally used in multi-filament formation experiments often cause significant surface damage. The growing number of applications for laser filaments requires fine control of their formation and propagation. We demonstrate, experimentally and theoretically, that the attraction and fusion of ultrashort beams with initial powers below the critical value enable the eventual formation of a filament downstream. Filament formation is delayed to a predetermined distance in space, avoiding optical damage to external beam optics while still enabling robust filaments with controllable properties as if formed from a single high power beam. This paradigm introduces new opportunities for filament engineering eliminating the nee...

  3. All-fiber phase-control-free coherent-beam combining toward femtosecond-pulse amplification

    Science.gov (United States)

    Kambayashi, Yuta; Yoshida, Minoru; Sasaki, Toshiki; Yoshikawa, Masashi

    2017-01-01

    Our present work is to develop an all-fiber coherent-beam-combining system that achieves a high-energy femtosecond-pulse fiber laser beyond pulse energy limits due to the nonlinear effects in fiber amplifiers. Coherent-beam combining (CBC) using optical fibers is technically difficult because the optical phases and the polarizations in the optical fibers fluctuate due to disturbances. We developed an all-fiber passive CBC system that does not need to control optical phases and polarizations that achieved a beam-combining efficiency of 95.9%. The combined output changes of the passive CBC system are the less than 1.0% in full width.

  4. Electron beam characterization of a combined diode rf electron gun

    Directory of Open Access Journals (Sweden)

    R. Ganter

    2010-09-01

    Full Text Available Experimental and simulation results of an electron gun test facility, based on pulsed diode acceleration followed by a two-cell rf cavity at 1.5 GHz, are presented here. The main features of this diode-rf combination are: a high peak gradient in the diode (up to 100  MV/m obtained without breakdown conditioning, a cathode shape providing an electrostatic focusing, and an in-vacuum pulsed solenoid to focus the electron beam between the diode and the rf cavity. Although the test stand was initially developed for testing field emitter arrays cathodes, it became also interesting to explore the limits of this electron gun with metallic photocathodes illuminated by laser pulses. The ultimate goal of this test facility is to fulfill the requirements of the SwissFEL project of Paul Scherrer Institute [B. D. Patterson et al., New J. Phys. 12, 035012 (2010NJOPFM1367-263010.1088/1367-2630/12/3/035012]; a projected normalized emittance below 0.4  μm for a charge of 200 pC and a bunch length of less than 10 ps (rms. A normalized projected emittance of 0.23  μm with 13 pC has been measured at 5 MeV using a Gaussian laser longitudinal intensity distribution on the photocathode. Good agreements with simulations have been obtained for different electron bunch charge and diode geometries. Emittance measurements at a bunch charge below 1 pC were performed for different laser spot sizes in agreement with intrinsic emittance theory [e.g. 0.54  μm/mm of laser spot size (rms for Cu at 274 nm]. Finally, a projected emittance of 1.25+/-0.2  μm was measured with 200 pC and 100  MV/m diode gradient.

  5. Experimental demonstration of spatially coherent beam combining using optical parametric amplification.

    Science.gov (United States)

    Kurita, Takashi; Sueda, Keiichi; Tsubakimoto, Koji; Miyanaga, Noriaki

    2010-07-05

    We experimentally demonstrated coherent beam combining using optical parametric amplification with a nonlinear crystal pumped by random-phased multiple-beam array of the second harmonic of a Nd:YAG laser at 10-Hz repetition rate. In the proof-of-principle experiment, the phase jump between two pump beams was precisely controlled by a motorized actuator. For the demonstration of multiple-beam combining a random phase plate was used to create random-phased beamlets as a pump pulse. Far-field patterns of the pump, the signal, and the idler indicated that the spatially coherent signal beams were obtained on both cases. This approach allows scaling of the intensity of optical parametric chirped pulse amplification up to the exa-watt level while maintaining diffraction-limited beam quality.

  6. Astronomical Instrumentation System Markup Language

    Science.gov (United States)

    Goldbaum, Jesse M.

    2016-05-01

    The Astronomical Instrumentation System Markup Language (AISML) is an Extensible Markup Language (XML) based file format for maintaining and exchanging information about astronomical instrumentation. The factors behind the need for an AISML are first discussed followed by the reasons why XML was chosen as the format. Next it's shown how XML also provides the framework for a more precise definition of an astronomical instrument and how these instruments can be combined to form an Astronomical Instrumentation System (AIS). AISML files for several instruments as well as one for a sample AIS are provided. The files demonstrate how AISML can be utilized for various tasks from web page generation and programming interface to instrument maintenance and quality management. The advantages of widespread adoption of AISML are discussed.

  7. Coherent beam combination of three two-tone fiber amplifiers using stochastic parallel gradient descent algorithm.

    Science.gov (United States)

    Zhou, Pu; Ma, Yanxing; Wang, Xiaolin; Ma, Haotong; Xu, Xiaojun; Liu, Zejin

    2009-10-01

    Multitone radiation is a promising technique to mitigate stimulated Brillouin scattering effects in narrow-linewidth fiber amplifiers. We demonstrate coherent beam combination of three two-tone fiber amplifiers using a stochastic parallel gradient descent (SPGD) algorithm. Phase control on the fiber amplifiers are performed by running the SPGD algorithm on a digital signal processor. The contrast of far-field intensity pattern of a coherently combined beam is more than 85%. Experimental results validate that a single-frequency seed laser is not indispensable for coherent beam combination in master oscillator power amplifier configuration.

  8. First beam test of a combined ramp and squeeze at LHC

    CERN Document Server

    Wenninger, Jorg; Coello De Portugal - Martinez Vazquez, Jaime Maria; Gorzawski, Arkadiusz; Redaelli, Stefano; Schaumann, Michaela; Solfaroli Camillocci, Matteo; CERN. Geneva. ATS Department

    2015-01-01

    With increasing maturity of LHC operation it is possible to envisage more complex beam manipulations. At the same time operational efficiency receives increasing attention. So far ramping the beams to their target energy and squeezing the beams to smaller or higher beta are decoupled at the LHC. (De-)squeezing is always performed at the target energy, currently 6.5 TeV. Studies to combine the ramp and squeeze processes have been made for the LHC since 2011, but so far no experimental test with beam had ever performed. This note describes the first machine experiment with beam aiming at validating the combination of ramp and squeeze, the so-called combined ramp and squeeze (CRS).

  9. Combining generalized phase contrast with matched filtering into a versatile beam shaping system

    DEFF Research Database (Denmark)

    Glückstad, Jesper

    2009-01-01

    We adapt concepts from matched filtering to propose a method for generating reconfigurable multiple beams. Combined with the Generalized Phase Contrast (GPC) technique, the proposed method coined mGPC can yield dynamically reconfigurable optical beam arrays with high light efficiency for optical...

  10. Combined e-beam lithography using different energies

    Czech Academy of Sciences Publication Activity Database

    Krátký, Stanislav; Kolařík, Vladimír; Horáček, Miroslav; Meluzín, Petr; Král, Stanislav

    2017-01-01

    Roč. 177, JUN (2017), s. 30-34 ISSN 0167-9317 R&D Projects: GA TA ČR TE01020233; GA MŠk(CZ) LO1212; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : grayscale e-beam lithography * mix and match process * absorbed energy density * resist sensitivity * micro-optical elements Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.806, year: 2016

  11. Wavelength beam combining of a 980-nm tapered diode laser bar in an external cavity

    DEFF Research Database (Denmark)

    Vijayakumar, Deepak; Jensen, Ole Bjarlin; Thestrup Nielsen, Birgitte

    2010-01-01

    solution for preserving the beam quality of the bar in the range of that of a single emitter and at the same time, enabling the power scaling. We report spectral beam combining applied to a 12 emitter tapered laser bar at 980 nm. The external cavity has been designed for a wavelength separation of 4.0 nm......High power diode lasers are used in a large number of applications. A limiting factor for more widespread use of broad area lasers is the poor beam quality. Gain guided tapered diode lasers are ideal candidates for industrial applications that demands watt level output power with good beam quality...

  12. Combined in-beam gamma-ray and conversion electron spectroscopy with radioactive ion beams

    Directory of Open Access Journals (Sweden)

    Konki J.

    2013-12-01

    Full Text Available In-beam gamma-ray and electron spectroscopy have been widely used as tools to study the broad variety of phenomena in nuclear structure. The SPEDE spectrometer is a new device to be used in conjunction with the MINIBALL germanium detector array to enable the detection of internal conversion electrons in coincidence with gamma rays from de-exciting nuclei in radioactive ion beam experiments at the upcoming HIE-ISOLDE facility at CERN, Switzerland. Geant4 simulations were carried out in order to optimise the design and segmentation of the silicon detector to achieve good energy resolution and performance.

  13. A Plasma Based Beam Combiner for Very High Fluence and Energy

    Science.gov (United States)

    Kirkwood, Robert

    2017-10-01

    Recent work at NIF has demonstrated a plasma-based optic that combines the energy and fluence of many laser beams into a single bright beam, thus creating a new technique for designing future high energy density physics experiments. The technique uses the Cross Beam Energy Transfer (CBET) process and shows for the first time that a plasma can combine beams to produce a single beam that emerges with energy and fluence beyond that of any of those input for delivery to a range of experimental targets. In an initial demonstration multiple beams of the National Ignition Facility (NIF) laser have been combined in a plasma to produce a directed pulse of light with 4 +1 kJ of energy in its 1 ns duration which is 3.6 times the energy and 3.2 times the fluence of any of the incident beams during that period and is NIFs brightest 1ns duration beam of UV light. These enhancements are due to the non-linear interaction of the beams with a self-generated plasma diffractive optic which is far more damage resistant than existing solid state optics, and is inherently capable of producing much higher single beam fluence and radiance than solid state refractive or reflective optics can. The initial results are presently being used to further validate models of CBET which predict a larger number of non-resonant pump beams will scale up outputs still further. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  14. 30 Watts mid-infrared optical parametric oscillator based on spectral beam combination technology

    Science.gov (United States)

    Shang, Yaping; Wang, Peng; Li, Xiao; Xu, Xiaojun

    2017-01-01

    Limited by the thermal effects and the laser-induced damage characteristics of the non-linear crystals, mid-infrared (MIR) output power of single optical parametric oscillator (OPO) is hard to get further promoted with excellent beam quality. An alternative solution is the multiple-beams combination technology, which exactly provided an effective approach for decreasing the thermal effects and the damage risk of the OPO system under high power operation. In this letter, the experimental study on the spectral beam combination of three idler MIR lasers was carried out for the first time. An optical parametric system with MIR output power of 30 W at 3130nm, 3352nm, and 3670nm was finally obtained. Experimental results indicated that the beam quality M2 factors of the combined laser were measured to be 1.76 and 2.42 in the horizontal and vertical directions, respectively, which confirmed the feasibility of the schematic design.

  15. Biographical encyclopedia of astronomers

    CERN Document Server

    Trimble, Virginia; Williams, Thomas; Bracher, Katherine; Jarrell, Richard; Marché, Jordan; Palmeri, JoAnn; Green, Daniel

    2014-01-01

    The Biographical Encyclopedia of Astronomers is a unique and valuable resource for historians and astronomers alike. It includes approx. 1850 biographical sketches on astronomers from antiquity to modern times. It is the collective work of 430 authors edited by an editorial board of 8 historians and astronomers. This reference provides biographical information on astronomers and cosmologists by utilizing contemporary historical scholarship. The fully corrected and updated second edition adds approximately 300 biographical sketches. Based on ongoing research and feedback from the community, the new entries will fill gaps and provide expansions. In addition, greater emphasis on Russo phone astronomers and radio astronomers is given. Individual entries vary from 100 to 1500 words, including the likes of the super luminaries such as Newton and Einstein, as well as lesser-known astronomers like Galileo's acolyte, Mario Guiducci.

  16. Near-diffraction-limited segmented broad area diode laser based on off-axis spectral beam combining

    DEFF Research Database (Denmark)

    Jensen, O.B.; Thestrup Nielsen, Birgitte; Andersen, Peter E.

    2006-01-01

    The beam quality of a 500-mu m-wide broad area diode laser with five active segments has been improved beyond the beam quality of the individual segments. The principle of this new laser system is based on off-axis feedback in combination with spectral beam combining. By using a double-feedback s...

  17. Coherent Beam Combining of Fiber Amplifiers via LOCSET (Postprint)

    Science.gov (United States)

    2012-07-10

    relies on self-phase locking via passive coupling mechanisms (ie., fiber ring [13]and Self-Fom1er cavity [14]) to coherently combine multiple lasers...single-frequency Non-Planar Ring Oscillator (NPRO) was used to seed sixteen polarization maintaining (PM) fiber amplifiers. Each amplifier chain...of America B 22, 347-353 (2005). [21] A. Flores, T. M. Shay, C. A. Lu, C. A. Robin, B. Pulford, A. D. Sanchez, D. Hult, and K. Rowland , “Coherent

  18. Model for Atmospheric Propagation of Spatially Combined Laser Beams

    Science.gov (United States)

    2016-09-01

    are various types of SSL structures but only fiber and slab SSLs have been used as DE weapons. 2.4.2.1 Slab Solid-State Lasers In a slab SSL, the gain...Demonstration (MLD) that leveraged slab SSL technology. In 2010, the MLD project group coherently combined seven 15 kW slab SSLs to create a 1.064 µm laser with...an output power of 105 kW [1]. During field testing, the MLD successfully tracked and engaged small boats in a marine environment. In May 2011, a

  19. High-power spectral beam combining of linearly polarized Tm:fiber lasers.

    Science.gov (United States)

    Shah, Lawrence; Sims, R Andrew; Kadwani, Pankaj; Willis, Christina C C; Bradford, Joshua B; Sincore, Alex; Richardson, Martin

    2015-02-01

    To date, high-power scaling of Tm:fiber lasers has been accomplished by maximizing the power from a single fiber aperture. In this work, we investigate power scaling by spectral beam combination of three linearly polarized Tm:fiber MOPA lasers using dielectric mirrors with a steep transition from highly reflective to highly transmissive that enable a minimum wavelength separation of 6 nm between individual laser channels within the wavelength range from 2030 to 2050 nm. Maximum output power is 253 W with M(2)<2, ultimately limited by thermal lensing in the beam combining elements.

  20. Coherent beam combining and noise analysis of a colliding pulse modelocked VECSEL.

    Science.gov (United States)

    Link, Sandro M; Waldburger, Dominik; Alfieri, Cesare G E; Golling, Matthias; Keller, Ursula

    2017-08-07

    Optically-pumped SESAM-modelocked semiconductor disk lasers have become interesting ultrafast lasers with gigahertz pulse repetition rates, high average power and adjustable lasing wavelength. It is well established that colliding pulse modelocking (CPM) can generate both shorter pulses and improved stability. These improvements however typically come at the expense of a more complex ring cavity and two output beams. So far similar modelocking results have been obtained with CPM vertical external-cavity surface-emitting lasers (VECSELs) and with SESAM-modelocked VECSELs or modelocked integrated external-cavity surface-emitting lasers (MIXSELs) in a linear cavity. However coherent beam combining of the two output beams of a CPM VECSEL could result in a significantly higher peak power. This is interesting for example for applications in biomedical microscopy and frequency metrology. Here we demonstrate with a more detailed noise analysis that for both output beams of a CPM VECSEL the pulse repetition rates and the carrier envelope offset frequencies are locked to each other. In contrast to standard SESAM-modelocked VECSELs in a linear cavity, we only have been able to actively stabilize the pulse repetition rate of the CPM VECSEL by cavity length control and not by pump-power control. Furthermore, a first coherent beam combining experiment of the two output beams is demonstrated.

  1. Scintillation reduction for combined Gaussian-vortex beam propagating through turbulent atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Berman, Gennady P [Los Alamos National Laboratory; Gorshkov, V. N. [NATL' TECH. UNIV. OF UA; Torous, S. V. [NATL' TECH. UNIV. OF UA

    2010-12-14

    We numerically examine the spatial evolution of the structure of coherent and partially coherent laser beams (PCBs), including the optical vortices, propagating in turbulent atmospheres, The influence of beam fragmentation and wandering relative to the axis of propagation (z-axis) on the value of the scintillation index (SI) of the signal at the detector is analyzed. A method for significantly reducing the SI, by averaging the signal at the detector over a set of PCBs, is described, This novel method is to generate the PCBs by combining two laser beams - Gaussian and vortex beams, with different frequencies (the difference between these two frequencies being significantly smaller than the frequencies themselves). In this case, the SI is effectively suppressed without any high-frequency modulators.

  2. 16 W output power by high-efficient spectral beam combining of DBR-tapered diode lasers

    DEFF Research Database (Denmark)

    Müller, André; Vijayakumar, Deepak; Jensen, Ole Bjarlin

    2011-01-01

    Up to 16 W output power has been obtained using spectral beam combining of two 1063 nm DBR-tapered diode lasers. Using a reflecting volume Bragg grating, a combining efficiency as high as 93.7% is achieved, resulting in a single beam with high spatial coherence. The result represents the highest...... output power achieved by spectral beam combining of two single element tapered diode lasers. Since spectral beam combining does not affect beam propagation parameters, M2-values of 1.8 (fast axis) and 3.3 (slow axis) match the M2- values of the laser with lowest spatial coherence. The principle...... of spectral beam combining used in our experiments can be expanded to combine more than two tapered diode lasers and hence it is expected that the output power may be increased even further in the future....

  3. Cascaded multi-dithering technique using PZT modulators for high control bandwidth in coherent laser beam combining

    Science.gov (United States)

    Ahn, Hee Kyung; Kong, Hong Jin

    2017-09-01

    A cascaded multi-dithering (CMD) technique using piezoelectric ceramic transducer (PZT) tubes as phase modulators is proposed as a tool for obtaining high control bandwidth in coherent laser beam combination. To prove its validity, eight coherent fiber beam elements were combined using the CMD technique with PZT tubes. As a result, residual phase error was recorded to be λ/54 at 100 Hz control bandwidth, which is comparable to that of a four laser beam combination in the previous experiment. To our knowledge, this is the first case to date of combining eight laser beam elements using PZT tubes as phase modulators and achieving such good results.

  4. A large capacity time division multiplexed (TDM) laser beam combining technique enabled by nanosecond speed KTN deflector

    Science.gov (United States)

    Yin, Stuart (Shizhuo); Chao, Ju-Hung; Zhu, Wenbin; Chen, Chang-Jiang; Campbell, Adrian; Henry, Michael; Dubinskiy, Mark; Hoffman, Robert C.

    2017-08-01

    In this paper, we present a novel large capacity (a 1000+ channel) time division multiplexing (TDM) laser beam combining technique by harnessing a state-of-the-art nanosecond speed potassium tantalate niobate (KTN) electro-optic (EO) beam deflector as the time division multiplexer. The major advantages of TDM approach are: (1) large multiplexing capability (over 1000 channels), (2) high spatial beam quality (the combined beam has the same spatial profile as the individual beam), (3) high spectral beam quality (the combined beam has the same spectral width as the individual beam, and (4) insensitive to the phase fluctuation of individual laser because of the nature of the incoherent beam combining. The quantitative analyses show that it is possible to achieve over one hundred kW average power, single aperture, single transverse mode solid state and/or fiber laser by pursuing this innovative beam combining method, which represents a major technical advance in the field of high energy lasers. Such kind of 100+ kW average power diffraction limited beam quality lasers can play an important role in a variety of applications such as laser directed energy weapons (DEW) and large-capacity high-speed laser manufacturing, including cutting, welding, and printing.

  5. Direct Design of T-Beams for Combined Load of Bending and Torsion

    Directory of Open Access Journals (Sweden)

    A. S. Alnuaimi

    2007-12-01

    Full Text Available Tests were conducted on five reinforced concrete T-beams subjected to combined load of bending and torsion. Elastic stress field in conjunction with Nielsen's 2D yield criterion for reinforced concrete subjected to in-plane forces were used in the Direct Design Method for the design of reinforcement. The beam dimensions were: flange width = 600mm, flange thickness = 150mm, web width = 200mm, total depth = 600mm and beam length = 5.2m. Required reinforcement calculated using the Direct Design Method was compared with the ACI and BSI codes. It was found that the Direct Design Method requires longitudinal reinforcement similar to the ACI code but less than the BSI code. In the transverse direction, the Direct Design Method requires much less reinforcement than both codes. The main variable studied was the ratio of the maximum twisting moment to the bending moment which was varied between 0.6 and 1.5. Good agreement was found between the design and experimental failure loads. Most of the longitudinal and transverse steel yielded or reached near yield stress when the design load was approached. All beams failed near the design loads and undergone ductile behaviour until failure. The results indicate that the Direct Design Method can be successfully used to design reinforced concrete T-beams for the combined effect of bending and torsion loads.

  6. Fast Transverse Beam Instability Caused by Electron Cloud Trapped in Combined Function Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Antipov, Sergey [Univ. of Chicago, IL (United States)

    2017-03-01

    Electron cloud instabilities affect the performance of many circular high-intensity particle accelerators. They usually have a fast growth rate and might lead to an increase of the transverse emittance and beam loss. A peculiar example of such an instability is observed in the Fermilab Recycler proton storage ring. Although this instability might pose a challenge for future intensity upgrades, its nature had not been completely understood. The phenomena has been studied experimentally by comparing the dynamics of stable and unstable beam, numerically by simulating the build-up of the electron cloud and its interaction with the beam, and analytically by constructing a model of an electron cloud driven instability with the electrons trapped in combined function dipoles. Stabilization of the beam by a clearing bunch reveals that the instability is caused by the electron cloud, trapped in beam optics magnets. Measurements of microwave propagation confirm the presence of the cloud in the combined function dipoles. Numerical simulations show that up to 10$^{-2}$ of the particles can be trapped by their magnetic field. Since the process of electron cloud build-up is exponential, once trapped this amount of electrons significantly increases the density of the cloud on the next revolution. In a combined function dipole this multi-turn accumulation allows the electron cloud reaching final intensities orders of magnitude greater than in a pure dipole. The estimated fast instability growth rate of about 30 revolutions and low mode frequency of 0.4 MHz are consistent with experimental observations and agree with the simulations. The created instability model allows investigating the beam stability for the future intensity upgrades.

  7. Coherent beam combination using non-separable phase-controlled Dammann grating

    Science.gov (United States)

    Li, Shubin; Lu, Yancong

    2018-01-01

    We present an improved scheme for coherent beam combination using a type of non-separable phase-controlled Dammann grating (NPDG), which is capable of generating multiple equal-intensity diffraction orders with good uniformity and high efficiency in the far field. Compared with conventional separable two-dimensional (2D) Dammann gratings, the efficiency of such gratings is significantly improved around 10% due to the non-separable structure. Such improvement in the diffraction efficiency is of high significance for coherent laser combination. Furthermore, the phases of those diffraction orders for this type of gratings are only two-valued in the far field, which leads to a great simplification of phase matching during the procedure of coherent beam combination. As an example, a 5 × 5 NPDG with efficiency of 73.6% is theoretically designed and a NPDG sample with efficiency as high as 66.8% is experimentally fabricated by lithography and wet-etching techniques. Also, we implemented further a proof-of-principle experiment for coherent beam combination based on the 5 × 5 NPDG sample, and the results show that the combining efficiency is as high as 65.7%.

  8. Alignment of the Pixel and SCT Modules for the 2004 ATLAS Combined Test Beam

    Energy Technology Data Exchange (ETDEWEB)

    ATLAS Collaboration; Ahmad, A.; Andreazza, A.; Atkinson, T.; Baines, J.; Barr, A.J.; Beccherle, R.; Bell, P.J.; Bernabeu, J.; Broklova, Z.; Bruckman de Renstrom, P.A.; Cauz, D.; Chevalier, L.; Chouridou, S.; Citterio, M.; Clark, A.; Cobal, M.; Cornelissen, T.; Correard, S.; Costa, M.J.; Costanzo, D.; Cuneo, S.; Dameri, M.; Darbo, G.; de Vivie, J.B.; Di Girolamo, B.; Dobos, D.; Drasal, Z.; Drohan, J.; Einsweiler, K.; Elsing, M.; Emelyanov, D.; Escobar, C.; Facius, K.; Ferrari, P.; Fergusson, D.; Ferrere, D.; Flick,, T.; Froidevaux, D.; Gagliardi, G.; Gallas, M.; Gallop, B.J.; Gan, K.K.; Garcia, C.; Gavrilenko, I.L.; Gemme, C.; Gerlach, P.; Golling, T.; Gonzalez-Sevilla, S.; Goodrick, M.J.; Gorfine, G.; Gottfert, T.; Grosse-Knetter, J.; Hansen, P.H.; Hara, K.; Hartel, R.; Harvey, A.; Hawkings, R.J.; Heinemann, F.E.W.; Henss, T.; Hill, J.C.; Huegging, F.; Jansen, E.; Joseph, J.; Unel, M. Karagoz; Kataoka, M.; Kersten, S.; Khomich, A.; Klingenberg, R.; Kodys, P.; Koffas, T.; Konstantinidis, N.; Kostyukhin, V.; Lacasta, C.; Lari, T.; Latorre, S.; Lester, C.G.; Liebig, W.; Lipniacka, A.; Lourerio, K.F.; Mangin-Brinet, M.; Marti i Garcia, S.; Mathes, M.; Meroni, C.; Mikulec, B.; Mindur, B.; Moed, S.; Moorhead, G.; Morettini, P.; Moyse, E.W.J.; Nakamura, K.; Nechaeva, P.; Nikolaev, K.; Parodi, F.; Parzhitskiy, S.; Pater, J.; Petti, R.; Phillips, P.W.; Pinto, B.; Poppleton, A.; Reeves, K.; Reisinger, I.; Reznicek, P.; Risso, P.; Robinson, D.; Roe, S.; Rozanov, A.; Salzburger, A.; Sandaker, H.; Santi, L.; Schiavi, C.; Schieck, J.; Schultes, J.; Sfyrla, A.; Shaw, C.; Tegenfeldt, F.; Timmermans, C.J.W.P.; Toczek, B.; Troncon, C.; Tyndel, M.; Vernocchi, F.; Virzi, J.; Anh, T. Vu; Warren, M.; Weber, J.; Weber, M.; Weidberg, A.R.; Weingarten, J.; Wellsf, P.S.; Zhelezkow, A.

    2008-06-02

    A small set of final prototypes of the ATLAS Inner Detector silicon tracking system(Pixel Detector and SemiConductor Tracker), were used to take data during the 2004 Combined Test Beam. Data were collected from runs with beams of different flavour (electrons, pions, muons and photons) with a momentum range of 2 to 180 GeV/c. Four independent methods were used to align the silicon modules. The corrections obtained were validated using the known momenta of the beam particles and were shown to yield consistent results among the different alignment approaches. From the residual distributions, it is concluded that the precision attained in the alignmentof the silicon modules is of the order of 5 mm in their most precise coordinate.

  9. A layer correlation technique for pion energy calibration at the 2004 ATLAS Combined Beam Test

    Science.gov (United States)

    Abat, E.; Abdallah, J. M.; Addy, T. N.; Adragna, P.; Aharrouche, M.; Ahmad, A.; Akesson, T. P. A.; Aleksa, M.; Alexa, C.; Anderson, K.; Andreazza, A.; Anghinolfi, F.; Antonaki, A.; Arabidze, G.; Arik, E.; Atkinson, T.; Baines, J.; Baker, O. K.; Banfi, D.; Baron, S.; Barr, A. J.; Beccherle, R.; Beck, H. P.; Belhorma, B.; Bell, P. J.; Benchekroun, D.; Benjamin, D. P.; Benslama, K.; Bergeaas Kuutmann, E.; Bernabeu, J.; Bertelsen, H.; Binet, S.; Biscarat, C.; Boldea, V.; Bondarenko, V. G.; Boonekamp, M.; Bosman, M.; Bourdarios, C.; Broklova, Z.; Burckhart Chromek, D.; Bychkov, V.; Callahan, J.; Calvet, D.; Canneri, M.; Capeáns Garrido, M.; Caprini, M.; Cardiel Sas, L.; Carli, T.; Carminati, L.; Carvalho, J.; Cascella, M.; Castillo, M. V.; Catinaccio, A.; Cauz, D.; Cavalli, D.; Cavalli Sforza, M.; Cavasinni, V.; Cetin, S. A.; Chen, H.; Cherkaoui, R.; Chevalier, L.; Chevallier, F.; Chouridou, S.; Ciobotaru, M.; Citterio, M.; Clark, A.; Cleland, B.; Cobal, M.; Cogneras, E.; Conde Muino, P.; Consonni, M.; Constantinescu, S.; Cornelissen, T.; Correard, S.; Corso Radu, A.; Costa, G.; Costa, M. J.; Costanzo, D.; Cuneo, S.; Cwetanski, P.; Da Silva, D.; Dam, M.; Dameri, M.; Danielsson, H. O.; Dannheim, D.; Darbo, G.; Davidek, T.; De, K.; Defay, P. O.; Dekhissi, B.; Del Peso, J.; Del Prete, T.; Delmastro, M.; Derue, F.; Di Ciaccio, L.; Di Girolamo, B.; Dita, S.; Dittus, F.; Djama, F.; Djobava, T.; Dobos, D.; Dobson, M.; Dolgoshein, B. A.; Dotti, A.; Drake, G.; Drasal, Z.; Dressnandt, N.; Driouchi, C.; Drohan, J.; Ebenstein, W. L.; Eerola, P.; Efthymiopoulos, I.; Egorov, K.; Eifert, T. F.; Einsweiler, K.; El Kacimi, M.; Elsing, M.; Emelyanov, D.; Escobar, C.; Etienvre, A. I.; Fabich, A.; Facius, K.; Fakhr-Edine, A. I.; Fanti, M.; Farbin, A.; Farthouat, P.; Fassouliotis, D.; Fayard, L.; Febbraro, R.; Fedin, O. L.; Fenyuk, A.; Fergusson, D.; Ferrari, P.; Ferrari, R.; Ferreira, B. C.; Ferrer, A.; Ferrere, D.; Filippini, G.; Flick, T.; Fournier, D.; Francavilla, P.; Francis, D.; Froeschl, R.; Froidevaux, D.; Fullana, E.; Gadomski, S.; Gagliardi, G.; Gagnon, P.; Gallas, M.; Gallop, B. J.; Gameiro, S.; Gan, K. K.; Garcia, R.; Garcia, C.; Gavrilenko, I. L.; Gemme, C.; Gerlach, P.; Ghodbane, N.; Giakoumopoulou, V.; Giangiobbe, V.; Giokaris, N.; Glonti, G.; Goettfert, T.; Golling, T.; Gollub, N.; Gomes, A.; Gomez, M. D.; Gonzalez-Sevilla, S.; Goodrick, M. J.; Gorfine, G.; Gorini, B.; Goujdami, D.; Grahn, K.-J.; Grenier, P.; Grigalashvili, N.; Grishkevich, Y.; Grosse-Knetter, J.; Gruwe, M.; Guicheney, C.; Gupta, A.; Haeberli, C.; Haertel, R.; Hajduk, Z.; Hakobyan, H.; Hance, M.; Hansen, J. D.; Hansen, P. H.; Hara, K.; Harvey, A., Jr.; Hawkings, R. J.; Heinemann, F. E. W.; Henriques Correia, A.; Henss, T.; Hervas, L.; Higon, E.; Hill, J. C.; Hoffman, J.; Hostachy, J. Y.; Hruska, I.; Hubaut, F.; Huegging, F.; Hulsbergen, W.; Hurwitz, M.; Iconomidou-Fayard, L.; Jansen, E.; Jen-La Plante, I.; Johansson, P. D. C.; Jon-And, K.; Joos, M.; Jorgensen, S.; Joseph, J.; Kaczmarska, A.; Kado, M.; Karyukhin, A.; Kataoka, M.; Kayumov, F.; Kazarov, A.; Keener, P. T.; Kekelidze, G. D.; Kerschen, N.; Kersten, S.; Khomich, A.; Khoriauli, G.; Khramov, E.; Khristachev, A.; Khubua, J.; Kittelmann, T. H.; Klingenberg, R.; Klinkby, E. B.; Kodys, P.; Koffas, T.; Kolos, S.; Konovalov, S. P.; Konstantinidis, N.; Kopikov, S.; Korolkov, I.; Kostyukhin, V.; Kovalenko, S.; Kowalski, T. Z.; Krüger, K.; Kramarenko, V.; Kudin, L. G.; Kulchitsky, Y.; Lacasta, C.; Lafaye, R.; Laforge, B.; Lampl, W.; Lanni, F.; Laplace, S.; Lari, T.; Le Bihan, A.-C.; Lechowski, M.; Ledroit-Guillon, F.; Lehmann, G.; Leitner, R.; Lelas, D.; Lester, C. G.; Liang, Z.; Lichard, P.; Liebig, W.; Lipniacka, A.; Lokajicek, M.; Louchard, L.; Lourerio, K. F.; Lucotte, A.; Luehring, F.; Lund-Jensen, B.; Lundberg, B.; Ma, H.; Mackeprang, R.; Maio, A.; Maleev, V. P.; Malek, F.; Mandelli, L.; Maneira, J.; Mangin-Brinet, M.; Manousakis, A.; Mapelli, L.; Marques, C.; Garcia, S. Marti i.; Martin, F.; Mathes, M.; Mazzanti, M.; McFarlane, K. W.; McPherson, R.; Mchedlidze, G.; Mehlhase, S.; Meirosu, C.; Meng, Z.; Meroni, C.; Mialkovski, V.; Mikulec, B.; Milstead, D.; Minashvili, I.; Mindur, B.; Mitsou, V. A.; Moed, S.; Monnier, E.; Moorhead, G.; Morettini, P.; Morozov, S. V.; Mosidze, M.; Mouraviev, S. V.; Moyse, E. W. J.; Munar, A.; Myagkov, A.; Nadtochi, A. V.; Nakamura, K.; Nechaeva, P.; Negri, A.; Nemecek, S.; Nessi, M.; Nesterov, S. Y.; Newcomer, F. M.; Nikitine, I.; Nikolaev, K.; Nikolic-Audit, I.; Ogren, H.; Oh, S. H.; Oleshko, S. B.; Olszowska, J.; Onofre, A.; Padilla Aranda, C.; Paganis, S.; Pallin, D.; Pantea, D.; Paolone, V.; Parodi, F.; Parsons, J.; Parzhitskiy, S.; Pasqualucci, E.; Passmored, S. M.; Pater, J.; Patrichev, S.; Peez, M.; Perez Reale, V.; Perini, L.; Peshekhonov, V. D.; Petersen, J.; Petersen, T. C.; Petti, R.; Phillips, P. W.; Pina, J.; Pinto, B.; Podlyski, F.; Poggioli, L.; Poppleton, A.; Poveda, J.; Pralavorio, P.; Pribyl, L.; Price, M. J.; Prieur, D.; Puigdengoles, C.; Puzo, P.; RØhne, O.; Ragusa, F.; Rajagopalan, S.; Reeves, K.; Reisinger, I.; Rembser, C.; Bruckman de Renstrom, P. A.; Reznicek, P.; Ridel, M.; Risso, P.; Riu, I.; Robinson, D.; Roda, C.; Roe, S.; Rohne, O.; Romaniouk, A.; Rousseau, D.; Rozanov, A.; Ruiz, A.; Rusakovich, N.; Rust, D.; Ryabov, Y. F.; Ryjov, V.; Salto, O.; Salvachua, B.; Salzburger, A.; Sandaker, H.; Santamarina Rios, C.; Santi, L.; Santoni, C.; Saraiva, J. G.; Sarri, F.; Sauvage, G.; Says, L. P.; Schaefer, M.; Schegelsky, V. A.; Schiavi, C.; Schieck, J.; Schlager, G.; Schlereth, J.; Schmitt, C.; Schultes, J.; Schwemling, P.; Schwindling, J.; Seixas, J. M.; Seliverstov, D. M.; Serin, L.; Sfyrla, A.; Shalanda, N.; Shaw, C.; Shin, T.; Shmeleva, A.; Silva, J.; Simion, S.; Simonyan, M.; Sloper, J. E.; Smirnov, S. Yu; Smirnova, L.; Solans, C.; Solodkov, A.; Solovianov, O.; Soloviev, I.; Sosnovtsev, V. V.; Spanò, F.; Speckmayer, P.; Stancu, S.; Stanek, R.; Starchenko, E.; Straessner, A.; Suchkov, S. I.; Suk, M.; Szczygiel, R.; Tarrade, F.; Tartarelli, F.; Tas, P.; Tayalati, Y.; Tegenfeldt, F.; Teuscher, R.; Thioye, M.; Tikhomirov, V. O.; Timmermans, C. J. W. P.; Tisserant, S.; Toczek, B.; Tremblet, L.; Troncon, C.; Tsiareshka, P.; Tyndel, M.; Karagoez Unel, M.; Unal, G.; Unel, G.; Usai, G.; Van Berg, R.; Valero, A.; Valkar, S.; Valls, J. A.; Vandelli, W.; Vannucci, F.; Vartapetian, A.; Vassilakopoulos, V. I.; Vasilyeva, L.; Vazeille, F.; Vernocchi, F.; Vetter-Cole, Y.; Vichou, I.; Vinogradov, V.; Virzi, J.; Vivarelli, I.; de Vivie, J. B.; Volpi, M.; Anh, T. Vu; Wang, C.; Warren, M.; Weber, J.; Weber, M.; Weidberg, A. R.; Weingarten, J.; Wells, P. S.; Werner, P.; Wheeler, S.; Wiessmann, M.; Wilkens, H.; Williams, H. H.; Wingerter-Seez, I.; Yasu, Y.; Zaitsev, A.; Zenin, A.; Zenis, T.; Zenonos, Z.; Zhang, H.; Zhelezko, A.; Zhou, N.

    2011-06-01

    A new method for calibrating the hadron response of a segmented calorimeter is developed and successfully applied to beam test data. It is based on a principal component analysis of energy deposits in the calorimeter layers, exploiting longitudinal shower development information to improve the measured energy resolution. Corrections for invisible hadronic energy and energy lost in dead material in front of and between the calorimeters of the ATLAS experiment were calculated with simulated Geant4 Monte Carlo events and used to reconstruct the energy of pions impinging on the calorimeters during the 2004 Barrel Combined Beam Test at the CERN H8 area. For pion beams with energies between 20GeV and 180GeV, the particle energy is reconstructed within 3% and the energy resolution is improved by between 11% and 25% compared to the resolution at the electromagnetic scale.

  10. Alignment of the Pixel and SCT Modules for the 2004 ATLAS Combined Test Beam

    Science.gov (United States)

    Ahmad, A.; Andreazza, A.; Atkinson, T.; Baines, J.; Barr, A. J.; Beccherle, R.; Bell, P. J.; Bernabeu, J.; Broklova, Z.; Bruckman de Renstrom, P. A.; Cauz, D.; Chevalier, L.; Chouridou, S.; Citterio, M.; Clark, A.; Cobal, M.; Cornelissen, T.; Correard, S.; Costa, M. J.; Costanzo, D.; Cuneo, S.; Dameri, M.; Darbo, G.; de Vivie, J. B.; Di Girolamo, B.; Dobos, D.; Drasal, Z.; Drohan, J.; Einsweiler, K.; Elsing, M.; Emelyanov, D.; Escobar, C.; Facius, K.; Ferrari, P.; Fergusson, D.; Ferrere, D.; Flick, T.; Froidevaux, D.; Gagliardi, G.; Gallas, M.; Gallop, B. J.; Gan, K. K.; Garcia, C.; Gavrilenko, I. L.; Gemme, C.; Gerlach, P.; Golling, T.; Gonzalez-Sevilla, S.; Goodrick, M. J.; Gorfine, G.; Göttfert, T.; Grosse-Knetter, J.; Hansen, P. H.; Hara, K.; Härtel, R.; Harvey, A.; Hawkings, R. J.; Heinemann, F. E. W.; Henss, T.; Hill, J. C.; Huegging, F.; Jansen, E.; Joseph, J.; Karagöz Ünel, M.; Kataoka, M.; Kersten, S.; Khomich, A.; Klingenberg, R.; Kodys, P.; Koffas, T.; Konstantinidis, N.; Kostyukhin, V.; Lacasta, C.; Lari, T.; Latorre, S.; Lester, C. G.; Liebig, W.; Lipniacka, A.; Lourerio, K. F.; Mangin-Brinet, M.; Garcia, S. Marti i.; Mathes, M.; Meroni, C.; Mikulec, B.; Mindur, B.; Moed, S.; Moorhead, G.; Morettini, P.; Moyse, E. W. J.; Nakamura, K.; Nechaeva, P.; Nikolaev, K.; Parodi, F.; Parzhitskiy, S.; Pater, J.; Petti, R.; Phillips, P. W.; Pinto, B.; Poppleton, A.; Reeves, K.; Reisinger, I.; Reznicek, P.; Risso, P.; Robinson, D.; Roe, S.; Rozanov, A.; Salzburger, A.; Sandaker, H.; Santi, L.; Schiavi, C.; Schieck, J.; Schultes, J.; Sfyrla, A.; Shaw, C.; Tegenfeldt, F.; Timmermans, C. J. W. P.; Toczek, B.; Troncon, C.; Tyndel, M.; Vernocchi, F.; Virzi, J.; Anh, T. Vu; Warren, M.; Weber, J.; Weber, M.; Weidberg, A. R.; Weingarten, J.; Wells, P. S.; Zhelezko, A.

    2008-09-01

    A small set of final prototypes of the ATLAS Inner Detector silicon tracking system (Pixel Detector and SemiConductor Tracker), were used to take data during the 2004 Combined Test Beam. Data were collected from runs with beams of different flavour (electrons, pions, muons and photons) with a momentum range of 2 to 180 GeV/c. Four independent methods were used to align the silicon modules. The corrections obtained were validated using the known momenta of the beam particles and were shown to yield consistent results among the different alignment approaches. From the residual distributions, it is concluded that the precision attained in the alignment of the silicon modules is of the order of 5 μm in their most precise coordinate.

  11. Nicolaus Copernicus Astronomical Center

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    Nicolaus Copernicus Astronomical Center is the largest astronomical institution in Poland, located in Warsaw and founded in 1956. At present it is a government-funded research institute supervised by the Polish Academy of Sciences and licensed by the government of Poland to award PhD and doctor habilitatus degrees in astronomy and astrophysics. In September 1999 staff included 21 senior scientist...

  12. Euler: Genius Blind Astronomer Mathematician

    OpenAIRE

    Musielak, Dora

    2014-01-01

    Leonhard Euler, the most prolific mathematician in history, contributed to advance a wide spectrum of topics in celestial mechanics. At the Saint Petersburg Observatory, Euler observed sunspots and tracked the movements of the Moon. Combining astronomical observations with his own mathematical genius, he determined the orbits of planets and comets. Euler laid the foundations of the methods of planetary perturbations and solved many of the Newtonian mechanics problems of the eighteenth century...

  13. All-fiber 7x1 signal combiner for incoherent laser beam combining

    DEFF Research Database (Denmark)

    Noordegraaf, Danny; Maack, Martin D.; Skovgaard, Peter M. W.

    2011-01-01

    fibers have a core diameter of 17 μm and the output MM fiber has a core diameter of 100 μm. In a tapered section light gradually leaks out of the SM fibers and is captured by a surrounding fluorine-doped cladding. The combiner is tested up to 2.5 kW of combined output power and only a minor increase...

  14. Improved SPGD algorithm to avoid local extremum for incoherent beam combining

    Science.gov (United States)

    Yang, Guoqing; Liu, Lisheng; Jiang, Zhenhua; Wang, Tingfeng; Guo, Jin

    2017-01-01

    The stochastic parallel gradient descent (SPGD) algorithm and the fast steering mirrors (FSM) are applied for incoherent beam combining in this paper. An equation is derived to calculate the wavefront reflected from the FSM under certain control voltages and the relationship between the strength of random disturbances and the combing efficiency is discussed via simulations, indicating that the combining efficiency is inversely proportional to the square of the strength of disturbance. The maximum value of the acceptable disturbance can be determined though the fitting curve which presents an instructional way to reduce the disturbance in advance. Besides, the SPGD algorithm is improved to overcome the weakness of tending to be trapped in the local extremum in incoherent beam combining. In the proposed algorithm, pattern recognition is used to check whether the algorithm is trapped and an "additional move" can be applied to get out of local extremum. The results of simulations show that the proposed algorithm can improve the performance of the incoherent beam combining. Comparative simulations are conducted where the value of evaluation function is increased about 60% compared to the conventional algorithm under the same conditions. The threshold of disturbance also increases about 15% when the accepted value of evaluation function set to 0.8 in the normalized form showing the feasibility of the method. Also, statistical data shows the proposed method depends less on the gain coefficient.

  15. System analysis of wavelength beam combining of high-power diode lasers for photoacoustic endoscopy

    Science.gov (United States)

    Leggio, Luca; Gallego, Daniel C.; Gawali, Sandeep B.; Sánchez, Miguel; Rodriguez, Sergio; Osiński, Marek; Sacher, Joachim; Carpintero, Guillermo; Lamela, Horacio

    2016-04-01

    This paper, originally published on 27 April 2016, was replaced with a corrected/revised version on 8 June 2016. If you downloaded the original PDF but are unable to access the revision, please contact SPIE Digital Library Customer Service for assistance. The purpose of wavelength-beam combining (WBC) is to improve the output power of a multi-wavelength laser system while maintaining the quality of the combined beam. This technique has been primarily proposed for industrial applications, such as metal cutting and soldering, which require optical peak power between kilowatts and megawatts. In order to replace the bulkier solid-state lasers, we propose to use the WBC technique for photoacoustic (PA) applications, where a multi-wavelength focused beam with optical peak power between hundreds of watts up to several kilowatts is necessary to penetrate deeply into biological tissues. In this work we present an analytical study about the coupling of light beams emitted by diode laser bars at 808 nm, 880 nm, 910 nm, 940 nm, and 980 nm into a .

  16. Combined Compression and Shear Structural Evaluation of Stiffened Panels Fabricated Using Electron Beam Freeform Fabrication

    OpenAIRE

    Nelson, Erik Walter

    2008-01-01

    Unitized aircraft structures have the potential to be more efficient than current aircraft structures. The Electron Beam Freeform Fabrication (EBF3) process can be used to manufacture unitized aircraft structures. The structural efficiency of blade stiffened panels made with EBF3 was compared to panels made by integrally machining from thick plate. The panels were tested under two load cases in a combined compression-shear load test fixture. One load case tested the panels' responses to a...

  17. Combined Laser Beam Braze-Welding Process for Fluxless Al-Cu Connections

    OpenAIRE

    Solchenbach, Tobias; Plapper, Peter

    2013-01-01

    A combined laser beam welding and brazing process for Al-Cu connections in overlap configuration is investigated. Aluminium and copper for electric and electronic application is used for experiments without surface treatment or activation, e.g. by flux. Although Al and Cu have been considered as “not weldable”, the possibility of a thermal joining process, i.e., the weld-brazing, was proved. The inevitable formation of intermetallic compounds at the inter...

  18. Test of the ATLAS pion calibration scheme in the ATLAS combined test beam

    CERN Document Server

    Spanò, F

    2009-01-01

    Pion energy reconstruction is studied using the data collected during the 2004 ATLAS combined test beam. The strategy to extract corrections for the non-compensating nature of the ATLAS calorimeters for dead material losses and for leakage effects is discussed and assessed. The default ATLAS strategy based on a weighting technique of the energy deposits in calorimeter cells is presented and compared to a novel technique exploiting correlations among energy deposited in calorimeter layers.

  19. Fiber laser beam combining and power scaling progress: Air Force Research Laboratory Laser Division

    Science.gov (United States)

    Wagner, T. J.

    2012-02-01

    Numerous achievements have been made recently by researchers in the areas of fiber laser beam combining and power scaling. Industry has demonstrated multi-kW power from a single fiber amplifier, and a US national laboratory has coherently combined eight fiber amplifiers totaling 4 kW. This paper will survey the recent literature and then focus on fiber laser results from the Laser Division, Directed Energy Directorate of the Air Force Research Laboratory (AFRL). Progress has been made in the power scaling of narrow-linewidth fiber amplifiers, and we are transitioning lessons learned from PCF power scaling into monolithic architectures. SBS suppression has been achieved using a variety of techniques to lower the Brillioun gain, including acoustically tailored fiber, laser gain competition resulting from multitone seeding and inducing a longitudinal thermal gradient. We recently demonstrated a 32-channel coherent beam combination result using AFRL's phaselocking technique and are focused on exploring the limitations of this technique including linewidth broadening, kW-induced phase nonlinearities and auto-tuning methods for large channel counts. Additionally, we have recently refurbished our High Energy Laser Joint Technology Office-sponsored 16-amplifier fiber testbed to meet strict PER, spatial drift, power stability and beam quality requirements.

  20. Scaling to Ultra-High Intensities by High-Energy Petawatt Beam Combining

    Energy Technology Data Exchange (ETDEWEB)

    Siders, C W; Jovanovic, I; Crane, J; Rushford, M; Lucianetti, A; Barty, C J

    2006-06-23

    The output pulse energy from a single-aperture high-energy laser amplifier (e.g. fusion lasers such as NIF and LMJ) are critically limited by a number of factors including optical damage, which places an upper bound on the operating fluence; parasitic gain, which limits together with manufacturing costs the maximum aperture size to {approx} 40-cm; and non-linear phase effects which limits the peak intensity. For 20-ns narrow band pulses down to transform-limited sub-picosecond pulses, these limiters combine to yield 10-kJ to 1-kJ maximum pulse energies with up to petawatt peak power. For example, the Advanced Radiographic Capability (ARC) project at NIF is designed to provide kilo-Joule pulses from 0.75-ps to 50-ps, with peak focused intensity above 10{sup 19} W/cm{sup 2}. Using such a high-energy petawatt (HEPW) beamline as a modular unit, they discuss large-scale architectures for coherently combining multiple HEPW pulses from independent apertures, called CAPE (Coherent Addition of Pulses for Energy), to significantly increase the peak achievable focused intensity. Importantly, the maximum intensity achievable with CAPE increases non-linearly. Clearly, the total integrated energy grows linearly with the number of apertures N used. However, as CAPE combines beams in the focal plane by increasing the angular convergence to focus (i.e. the f-number decreases), the foal spot diameter scales inversely with N. Hence the peak intensity scales as N{sup 2}. Using design estimates for the focal spot size and output pulse energy (limited by damage fluence on the final compressor gratings) versus compressed pulse duration in the ARC system, Figure 2 shows the scaled focal spot intensity and total energy for various CAPE configurations from 1,2,4, ..., up to 192 total beams. They see from the fixture that the peak intensity for event modest 8 to 16 beam combinations reaches the 10{sup 21} to 10{sup 22} W/cm{sup 2} regime. With greater number of apertures, or with

  1. Thermal tuning of volume Bragg gratings for spectral beam combining of high-power fiber lasers.

    Science.gov (United States)

    Drachenberg, Derrek R; Andrusyak, Oleksiy; Venus, George; Smirnov, Vadim; Glebov, Leonid B

    2014-02-20

    High-radiance lasers are desired for many applications in defense and manufacturing. Spectral beam combining (SBC) by volume Bragg gratings (VBGs) is a very promising method for high-radiance lasers that need to achieve 100 kW level power. Laser-induced heating of VBGs under high-power radiation presents a challenge for maintaining Bragg resonance at various power levels without mechanical realignment. A novel thermal tuning technique and apparatus is presented that enables maintaining peak efficiency operation of the SBC system at various power levels without any mechanical adjustment. The method is demonstrated by combining two high-power ytterbium fiber lasers with high efficiency from low power to full combined power of 300 W (1.5 kW effective power), while maintaining peak combining efficiency within 0.5%.

  2. The amateur astronomer

    CERN Document Server

    Moore, Patrick

    2006-01-01

    Introduces astronomy and amateur observing together. This edition includes photographs and illustrations. The comprehensive appendices provide hints and tips, as well as data for every aspect of amateur astronomy. This work is useful for amateur astronomers

  3. The Galway astronomical Stokes polarimeter: optical development

    Directory of Open Access Journals (Sweden)

    Sheehan B.

    2010-06-01

    Full Text Available The acquisition time of astronomical polarimeters has in the past been restricted to by the use of polarimeters utilizing modulated or rotating components [1]. If the polarisation state being measured is changing in the order of nanoseconds, how does one measure this? The Galway Astronomical Stokes Polarimeter (GASP is an instantaneous full Stokes Division Of Amplitude Polarimeter (DOAP that has been developed for astronomical imaging polarimetry. It also uses just one camera thus restricting the acquisition time to photon statistics. Following the work of Compain and Drévillon [2], the main component - the Retarding Beam-Splitter, was redesigned and enhanced for imaging use. We present how the polarization and imaging optics were developed to create a broadband imaging instantaneous polarimeter.

  4. Astronomical Polarimeters and Features of Polarimetric Observations

    Science.gov (United States)

    Morozhenko, A. V.; Vid'machenko, A. P.

    2005-01-01

    We present a general description of ground-based astronomical polarimeters, and provide a detailed description of the spectropolarimeter of the Main astronomical observatory (MAO) of a National Academy of Sciences of Ukraine (NASU). Using a polarization modulator of a rotating quarter-wave phase plate (FP) allows us to measure the parameters of linear and circular polarization simultaneously. In 1983 O. I. Bugaenko with the colleagues from MAO of NASU produced an automatic astronomical spectropolarimeter (ASP), which used a continuous rotation of polarizer with frequency of 61 Hz. Observations in two beam modes allowed it to accommodate changes of transparency of the Earth's atmosphere, air mass the of observational object, inexactness of guiding and displacement from an optical axis because of atmospheric turbulence. In 1995 the spectropolarimeter was upgraded and its spectral interval expanded to 1 micron. Sources of errors and methods of their elimination are described.

  5. Durability of Steel Fibres Reinforcement Concrete Beams in Chloride Environment Combined with Inhibitor

    Directory of Open Access Journals (Sweden)

    AbdelMonem Masmoudi

    2016-01-01

    Full Text Available This paper presented the effect of the combination of an inhibitor and steel fibre reinforced concrete (SFRC for concrete structures in chloride environments. Twelve beams were cast and tested to study their flexural behavior. The morphology of steel surfaces using the inhibitor after observing the scanning electron microscope showed a low layer of corrosion products. The steel surface immersed in the inhibitor free solution was seen to have been subject to chloride ions attacks as shown in this study. The interest to the field of the present study is the relatively higher durability of the performance when using the inhibitor. Crack width and crack spacing for beams under the same load showed that the use of SFRC with the inhibitor for concrete structures in chloride environments must have transferred tension across cracks that led to reducing crack spacing without any chloride ions attack.

  6. A Layer Correlation Technique for Pion Energy Calibration at the 2004 ATLAS Combined Beam Test

    CERN Document Server

    Grahn, Karl-Johan

    2009-01-01

    A new method for calibrating the hadron response of a segmented calorimeter is developed. It is based on a principal component analysis of the calorimeter layer energy deposits, exploiting longitudinal shower development information to improve the measured energy resolution. Corrections for invisible hadronic energy and energy lost in dead material in front of and between the ATLAS calorimeters were calculated with simulated Geant4 Monte Carlo events and used to reconstruct the energy of pions impinging on the calorimeters during the 2004 Barrel Combined Beam Test at the CERN H8 area. For pion beams with energies between 20 and 180 GeV, the particle energy is reconstructed within 3% and the energy resolution is improved by about 20% compared to the electromagnetic scale.

  7. A Layer Correlation Technique for ATLAS Calorimetry Calibration at the 2004 ATLAS Combined Beam Test

    CERN Document Server

    Carli, T; Spanò, F; Speckmayer, P

    2008-01-01

    A method for calibrating the response of a segmented calorimeter to hadrons is developed. The ansatz is that information on longitudinal shower fluctuations gained from a principal component analysis of the layer energy depositions can improve energy resolution by correcting for hadronic invisible energy and dead material losses: projections along the eigenvectors of the correlation matrix are used as input for the calibration. The technique is used to reconstruct the energy of pions impinging on the ATLAS calorimeters during the 2004 Barrel Combined Beam Test at the CERN H8 area. Simulated Monte Carlo events are used to derive corrections for invisible energy lost in nuclear reactions and in dead material in front and in between the calorimeters. For pion beams with energies between 20 and 180 GeV, the particle energy is reconstructed within 3% and the resolution is improved by about 20%.

  8. Designing and optimizing highly efficient grating for high-brightness laser based on spectral beam combining

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ying-Ying, E-mail: xclin@semi.ac.cn, E-mail: yangyy@semi.ac.cn; Zhao, Ya-Ping; Wang, Li-Rong; Zhang, Ling; Lin, Xue-Chun, E-mail: xclin@semi.ac.cn, E-mail: yangyy@semi.ac.cn [Laboratory of All Solid State Light Sources, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China)

    2015-03-14

    A highly efficient nano-periodical grating is theoretically investigated for spectral beam combining (SBC) and is experimentally implemented for attaining high-brightness laser from a diode laser array. The rigorous coupled-wave analysis with the S matrix method is employed to optimize the parameters of the grating. According the optimized parameters, the grating is fabricated and plays a key role in SBC cavity. The diffraction efficiency of this grating is optimized to 95% for the output laser which is emitted from the diode laser array. The beam parameter product of 3.8 mm mrad of the diode laser array after SBC is achieved at the output power of 46.3 W. The optical-to-optical efficiency of SBC cavity is measured to be 93.5% at the maximum operating current in the experiment.

  9. Multi-octave spectral beam combiner on ultra-broadband photonic integrated circuit platform.

    Science.gov (United States)

    Stanton, Eric J; Heck, Martijn J R; Bovington, Jock; Spott, Alexander; Bowers, John E

    2015-05-04

    We present the design of a novel platform that is able to combine optical frequency bands spanning 4.2 octaves from ultraviolet to mid-wave infrared into a single, low M2 output waveguide. We present the design and realization of a key component in this platform that combines the wavelength bands of 350 nm - 1500 nm and 1500 nm - 6500 nm with demonstrated efficiency greater than 90% in near-infrared and mid-wave infrared. The multi-octave spectral beam combiner concept is realized using an integrated platform with silicon nitride waveguides and silicon waveguides. Simulated bandwidth is shown to be over four octaves, and measured bandwidth is shown over two octaves, limited by the availability of sources.

  10. Combining tissue-phantom ratios to provide a beam-quality specifier for flattening filter free photon beams.

    Science.gov (United States)

    Dalaryd, Mårten; Knöös, Tommy; Ceberg, Crister

    2014-11-01

    There are currently several commercially available radiotherapy treatment units without a flattening filter in the beam line. Unflattened photon beams have an energy and lateral fluence distribution that is different from conventional beams and, thus, their attenuation properties differ. As a consequence, for flattening filter free (FFF) beams, the relationship between the beam-quality specifier TPR20,10 and the Spencer-Attix restricted water-to-air mass collision stopping-power ratios, L̄/ρair (water), may have to be refined in order to be used with equivalent accuracy as for beams with a flattening filter. The purpose of this work was twofold. First, to study the relationship between TPR20,10 and L̄/ρair (water) for FFF beams, where the flattening filter has been replaced by a metal plate as in most clinical FFF beams. Second, to investigate the potential of increasing the accuracy in determining L̄/ρair (water) by adding another beam-quality metric, TPR10,5. The relationship between L̄/ρair (water) and %dd(10)x for beams with and without a flattening filter was also included in this study. A total of 24 realistic photon beams (10 with and 14 without a flattening filter) from three different treatment units have been used to calculate L̄/ρair (water), TPR20,10, and TPR10,5 using the EGSnrc Monte Carlo package. The relationship between L̄/ρair (water) and the dual beam-quality specifier TPR20,10 and TPR10,5 was described by a simple bilinear equation. The relationship between the photon beam-quality specifier %dd(10)x used in the AAPM's TG-51 dosimetry protocol and L̄/ρair (water) was also investigated for the beams used in this study, by calculating the photon component of the percentage depth dose at 10 cm depth with SSD 100 cm. The calculated L̄/ρair (water) for beams without a flattening filter was 0.3% lower, on average, than for beams with a flattening filter and comparable TPR20,10. Using the relationship in IAEA, TRS-398 resulted in a root

  11. Observatory Sponsoring Astronomical Image Contest

    Science.gov (United States)

    2005-05-01

    and to provide a showcase for a broad range of astronomical research and celestial objects," Adams added. In addition, NRAO is developing enhanced data visualization techniques and data-processing recipes to assist radio astronomers in making quality images and in combining radio data with data collected at other wavelengths, such as visible-light or infrared, to make composite images. "We encourage all our telescope users to take advantage of these techniques to showcase their research," said Juan Uson, a member of the NRAO scientific staff and the observatory's EPO scientist. "All these efforts should demonstrate the vital and exciting roles that radio telescopes, radio observers, and the NRAO play in modern astronomy," Lo said. "While we want to encourage images that capture the imagination, we also want to emphasize that extra effort invested in enhanced imagery also will certainly pay off scientifically, by revealing subtleties and details that may have great significance for our understanding of astronomical objects," he added. Details of the NRAO Image Contest, which will become an annual event, are on the observatory's Web site. The observatory will announce winners on October 15. The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

  12. JouFLU: an upgraded FLUOR beam combiner at the CHARA Array

    Science.gov (United States)

    Lhomé, E.; Scott, N.; ten Brummelaar, T.; Mollier, B.; Reess, J. M.; Chapron, F.; Buey, T.; Sevin, A.; Sturmann, J.; Sturmann, L.; Coudé du Foresto, V.

    2012-07-01

    FLUOR, which has been operational on CHARA since 2002, is an infrared fiber beam combiner. The telescope array will soon be fitted with an adaptive optics system, which will enhance the interferometer performance. In this framework, FLUOR has been entirely redeveloped and will be able to measure visibilities with higher accuracy and better sensitivity. The technical upgrades consist of improving some existing systems and developing new features. The bench, which is now remotely operable, primarily offers spectral dispersion (long fringes scanning), a more sensitive camera and a Fourier Transform Spectrometer mode. This paper presents the detailed opto-mechanical design of JouFLU (FLUOR rejuvenation), and the current instrument status.

  13. Blind deconvolution combined with level set method for correcting cupping artifacts in cone beam CT

    Science.gov (United States)

    Xie, Shipeng; Zhuang, Wenqin; Li, Baosheng; Bai, Peirui; Shao, Wenze; Tong, Yubing

    2017-02-01

    To reduce cupping artifacts and enhance contrast resolution in cone-beam CT (CBCT), in this paper, we introduce a new approach which combines blind deconvolution with a level set method. The proposed method focuses on the reconstructed image without requiring any additional physical equipment, is easily implemented on a single-scan acquisition. The results demonstrate that the algorithm is practical and effective for reducing the cupping artifacts and enhance contrast resolution on the images, preserves the quality of the reconstructed image, and is very robust.

  14. A new device for combined Coulomb excitation and isomeric conversion electron spectroscopy with fast fragmentation beams

    Energy Technology Data Exchange (ETDEWEB)

    Clement, E. [CEA Saclay, DSM/DAPNIA/SPhN, F-91191 Gif-sur-Yvette (France); GANIL, BP-5027, F-14076 Caen Cedex (France); Goergen, A. [CEA Saclay, DSM/DAPNIA/SPhN, F-91191 Gif-sur-Yvette (France)], E-mail: andreas.goergen@cea.fr; Korten, W. [CEA Saclay, DSM/DAPNIA/SPhN, F-91191 Gif-sur-Yvette (France); Buerger, A. [CEA Saclay, DSM/DAPNIA/SPhN, F-91191 Gif-sur-Yvette (France); Helmholtz-Institut fuer Strahlen- und Kernphysik, Universitaet Bonn, D-53115 Bonn (Germany); Chatillon, A.; Le Coz, Y.; Theisen, Ch. [CEA Saclay, DSM/DAPNIA/SPhN, F-91191 Gif-sur-Yvette (France); Zielinska, M. [CEA Saclay, DSM/DAPNIA/SPhN, F-91191 Gif-sur-Yvette (France); Heavy Ion Laboratory, Warsaw University, Warsaw PL-02097 (Poland); Blank, B. [CEN Bordeaux-Gradignan, Universite Bordeaux I-CNRS/IN2P3, F-33175 Gradignan Cedex (France); Davies, P.J.; Fox, S.P. [Department of Physics, University of York, York YO10 5DD (United Kingdom); Gerl, J. [Gesellschaft fuer Schwerionenforschung, D-64291 Darmstadt (Germany); Georgiev, G.; Grevy, S. [GANIL, BP-5027, F-14076 Caen Cedex (France); Iwanicki, J. [Heavy Ion Laboratory, Warsaw University, Warsaw PL-02097 (Poland); Jenkins, D.G.; Johnston-Theasby, F.; Joshi, P. [Department of Physics, University of York, York YO10 5DD (United Kingdom); Matea, I. [CEN Bordeaux-Gradignan, Universite Bordeaux I-CNRS/IN2P3, F-33175 Gradignan Cedex (France); Napiorkowski, P.J. [Heavy Ion Laboratory, Warsaw University, Warsaw PL-02097 (Poland)] (and others)

    2008-03-21

    A new setup has been designed to perform Coulomb excitation experiments with fragmentation beams at intermediate energy and to measure at the same time conversion electrons from isomeric states populated in the fragmentation reaction. The newly designed setup is described and experimental results from a first experiment are shown. Radioactive even-even nuclei in the mass region A{approx_equal}70 close to the N=Z line were Coulomb excited after fragmentation of an intense primary {sup 78}Kr beam and selection in flight with the LISE3 spectrometer at GANIL. The {gamma} rays emitted after Coulomb excitation were detected in an array of four large segmented HPGe clover detectors in a very close geometry. The scattered ions were identified in a stack of highly segmented annular silicon detectors combined with a time-of-flight measurement using beam tracking detectors. Conversion electrons from isomeric 0{sub 2}{sup +} states decaying via electric monopole transitions were detected in an array of segmented cooled silicon detectors surrounding a telescope of plastic scintillators. Reduced transitions probabilities B(E2;0{sub 1}{sup +}{yields}2{sub 1}{sup +}) were deduced for several stable and radioactive nuclei.

  15. Tests of Local Hadron Calibration approaches in ATLAS Combined Beam Tests

    CERN Document Server

    Pospelov, G; The ATLAS collaboration

    2010-01-01

    The three Atlas calorimeter systems in the region of the forward crack at |eta| = 3.2 in the nominal Atlas setup and a typical section of the two barrel calorimeters at |eta| = 0.45 of Atlas have been exposed to combined beam tests with single electrons and pions. Detailed shower shape studies of electrons and pions with comparisons to various Geant4 based simulations utilizing different physics lists are presented for the endcap testbeam. The local hadronic calibration approach as used in the full Atlas setup has been applied to the endcap test beam data. An extension of it using layer correlations has been tested on the barrel test beam data. Both methods utilize modular correction steps based on shower shape variables to correct for invisible energy inside the reconstructed clusters in the calorimeters (compensation) and for lost energy deposits outside of the reconstructed clusters (dead material and out-of-cluster deposits). Results for both methods and comparisons to MC simulations are presented.

  16. Two-beam combined 3.36  J, 100  Hz diode-pumped high beam quality Nd:YAG laser system.

    Science.gov (United States)

    Qiu, J S; Tang, X X; Fan, Z W; Wang, H C; Liu, H

    2016-07-20

    In this paper, we develop a diode-pumped all-solid-state high-energy and high beam quality Nd:YAG laser system. A master oscillator power amplifier structure is used to provide a high pulse energy laser output with a high repetition rate. In order to decrease the amplifier working current so as to reduce the impact of the thermal effect on the beam quality, a beam splitting-amplifying-combining scheme is adopted. The energy extraction efficiency of the laser system is 50.68%. We achieve 3.36 J pulse energy at a 100 Hz repetition rate with a pulse duration of 7.1 ns, a far-field beam spot 1.71 times the diffraction limit, and 1.07% energy stability (RMS).

  17. Atlas of Astronomical Discoveries

    CERN Document Server

    Schilling, Govert

    2011-01-01

    Four hundred years ago in Middelburg, in the Netherlands, the telescope was invented. The invention unleashed a revolution in the exploration of the universe. Galileo Galilei discovered mountains on the Moon, spots on the Sun, and moons around Jupiter. Christiaan Huygens saw details on Mars and rings around Saturn. William Herschel discovered a new planet and mapped binary stars and nebulae. Other astronomers determined the distances to stars, unraveled the structure of the Milky Way, and discovered the expansion of the universe. And, as telescopes became bigger and more powerful, astronomers delved deeper into the mysteries of the cosmos. In his Atlas of Astronomical Discoveries, astronomy journalist Govert Schilling tells the story of 400 years of telescopic astronomy. He looks at the 100 most important discoveries since the invention of the telescope. In his direct and accessible style, the author takes his readers on an exciting journey encompassing the highlights of four centuries of astronomy. Spectacul...

  18. Analysis of the effects of mismatched errors on coherent beam combining based on a self-imaging waveguide

    Energy Technology Data Exchange (ETDEWEB)

    Tao, R; Wang, X; Pu Zhou; Lei Si [College of Optoelectric Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

    2016-01-31

    A theoretical model of coherent beam combining (CBC) based on a self-imaging waveguide (SIW) is built and the effects of mismatched errors on SIW-based CBC are simulated and analysed numerically. With the combination of the theoretical model and the finite difference beam propagation method, two main categories of errors, assembly and nonassembly errors, are numerically studied to investigate their effect on the beam quality by using the M{sup 2} factor. The optimisation of the SIW and error control principle of the system is briefly discussed. The generalised methodology offers a good reference for investigating waveguide-based high-power coherent combining of fibre lasers in a comprehensive way. (lasers and laser beams)

  19. Measurements on Fast switches and combiners (FADIS-BC for High-Power Millimeter-wave beams based on dielectric beam splitters

    Directory of Open Access Journals (Sweden)

    Moro A.

    2012-09-01

    Full Text Available An upgraded version of a quasi-optical diplexer combiner, based on a resonating system coupling two transmission lines using three Dielectric Beam Splitters, has been realized and tested. This device is principally thought to combine power coming from different transmission lines into a single output or to switch the injected power between different outputs, but it could also be used as mode filter or in line viewing system for Electron Cyclotron Emission (ECE or Collective Thomson Scattering (CTS diagnostics. The design was implemented in order to link two transmission lines of the ECRH system on FTU, for power combination of two beams into a single line of the new ECRH launcher recently installed. This device is based on Dielectric Beam Splitters (DBS; it has been tested at low power in order to confirm the splitting ratio foreseen from simulation and its efficiency has been evaluated measuring the beam exiting the system. The design and the characterization of the diplexer combiner are reported in this paper.

  20. Korean Astronomical Calendar, Chiljeongsan

    Science.gov (United States)

    Lee, Eun Hee

    In fifteenth century Korea, there was a grand project for the astronomical calendar and instrument making by the order of King Sejong 世宗 (1418-1450). During this period, many astronomical and calendrical books including Islamic sources in Chinese versions were imported from Ming 明 China, and corrected and researched by the court astronomers of Joseon 朝鮮 (1392-1910). Moreover, the astronomers and technicians of Korea frequently visited China to study astronomy and instrument making, and they brought back useful information in the form of new published books or specifications of instruments. As a result, a royal observatory equipped with 15 types of instrument was completed in 1438. Two types of calendar, Chiljeongsan Naepyeon 七政算內篇 and Chiljeongsan Oepyeon 七政算外篇, based on the Chinese and Islamic calendar systems, respectively, were published in 1444 with a number of calendrical editions such as corrections and example supplements (假令) including calculation methods and results for solar and lunar eclipses.

  1. Combining the switched-beam and beam-steering capabilities in a 2-D phased array antenna system

    Science.gov (United States)

    Tsai, Yi-Che; Chen, Yin-Bing; Hwang, Ruey-Bing

    2016-01-01

    This paper presents the development, fabrication, and measurement of a novel beam-forming system consisting of 16 subarray antennas, each containing four aperture-coupled patch antennas, and the application of this system in smart wireless communication systems. The beam patterns of each of the subarray antennas can be switched toward one of nine zones over a half space by adjusting the specific phase delay angles among the four antenna elements. Furthermore, when all subarrays are pointed at the same zone, slightly continuous beam steering in around 1° increments can be achieved by dynamically altering the progressive phase delay angle among the subarrays. Phase angle calibration was implemented by coupling each transmitter output and down converter into the in-phase/quadrature baseband to calculate the correction factor to the weight. In addition, to validate the proposed concepts and the fabricated 2-D phased array antenna system, this study measured the far-field radiation patterns of the aperture-coupled patch array integrated with feeding networks and a phase-calibration system to carefully verify its spatially switched-beam and beam-steering characteristics at a center frequency of 2.4 GHz which can cover the industrial, scientific, and medical band and some long-term evolution applications. In addition, measured results were compared with calculated results, and agreement between them was observed.

  2. Tests of Local Hadron Calibration Approaches in ATLAS Combined Beam Tests

    CERN Document Server

    Grahn, KJ; The ATLAS collaboration; Pospelov, G

    2010-01-01

    Three ATLAS calorimeters in the region of the forward crack at $|eta| = 3.2$ in the nominal ATLAS setup and a typical section of the two barrel calorimeters at $|eta| = 0.45$ of ATLAS have been exposed to combined beam tests with single electrons and pions. Detailed shower shape studies of electrons and pions with comparisons to various Geant4 based simulations utilizing different physics lists are presented for the endcap testbeam. The local hadronic calibration approach as used in the full Atlas setup has been applied to the endcap testbeam data. An extension of it using layer correlations has been tested with the barrel test beam data. Both methods utilize modular correction steps based on shower shape variables to correct for invisible energy inside the reconstructed clusters in the calorimeters (compensation) and for lost energy deposits outside of the reconstructed clusters (dead material and out-of-cluster deposits). Results for both methods and comparisons to Monte-Carlo simulations are presented.

  3. TESTBEAM COORDINATION: 2nd ATLAS H8 Combined Test Beam Workshop

    CERN Document Server

    Di Girolamo, B

    The second ATLAS H8 Combined Test Beam Workshop took place at CERN on 24th and 25th November. After a first workshop in July to warm up the atmosphere, a lot of work has been done in the meantime and there was a clear need to get together again before the end of 2003. The morning of the first day has been devoted to an assessment of the status of the various elements needed for next year’s test beam in H8. Each sub-detector has been presenting the status of preparation, as well as the work in progress and still to be done. The picture has been completed with the first plans for the DAQ from the point of view of the sub-detectors requirements, and a status of the LVL1 elements. Finally, the status and the timescale for availability of the LVL2 and EF infrastructure have been presented. The final draft layout of the sub-detectors has been discussed (figures 1 and 2). A more detailed description of the layout is in preparation to include more information on dead material and on the ancillary detectors (scint...

  4. A deflection formula for single-span beams of constant section subjected to combined axial and transverse loads

    Science.gov (United States)

    Burke, Walter F

    1935-01-01

    In this paper there is presented a deflection formula for single-span beams of constant section subjected to combined axial and transverse loads of the types commonly encountered in airplane design. The form of the equation is obtainable by dimensional analysis. Tables and curves of the non dimensional coefficients are appended to facilitate the use of the formula. The equation is applied to the determination of the spring constant of a beam. Tables and curves are presented to show the variation of the spring constant with changes in the axial load and position along the beam.

  5. Quantitative measurements of electromechanical response with a combined optical beam and interferometric atomic force microscope

    Energy Technology Data Exchange (ETDEWEB)

    Labuda, Aleksander; Proksch, Roger [Asylum Research an Oxford Instruments Company, Santa Barbara, California 93117 (United States)

    2015-06-22

    An ongoing challenge in atomic force microscope (AFM) experiments is the quantitative measurement of cantilever motion. The vast majority of AFMs use the optical beam deflection (OBD) method to infer the deflection of the cantilever. The OBD method is easy to implement, has impressive noise performance, and tends to be mechanically robust. However, it represents an indirect measurement of the cantilever displacement, since it is fundamentally an angular rather than a displacement measurement. Here, we demonstrate a metrological AFM that combines an OBD sensor with a laser Doppler vibrometer (LDV) to enable accurate measurements of the cantilever velocity and displacement. The OBD/LDV AFM allows a host of quantitative measurements to be performed, including in-situ measurements of cantilever oscillation modes in piezoresponse force microscopy. As an example application, we demonstrate how this instrument can be used for accurate quantification of piezoelectric sensitivity—a longstanding goal in the electromechanical community.

  6. Jouvence of Fluor: Upgrades of a Fiber Beam Combiner at the CHARA Array

    Science.gov (United States)

    Scott, N. J.; Millan-Gabet, R.; Lhomé, E.; Ten Brummelaar, T. A.; Coudé Du Foresto, V.; Sturmann, J.; Sturmann, L.

    The FLUOR (Fiber Linked Unit for Optical Recombination) interferometric beam combiner located at the CHARA Array on Mt. Wilson, California has recently undergone a program of major upgrades known as Jouvence of FLUOR (JouFLU). These upgrades seek to improve the precision, use, and observing efficiency of FLUOR as well as introduce new modes of operation. A Fourier Transform Spectrograph (FTS) mode and a spectral dispersion mode have been added to improve calibration and data collection. New mechanized stages and new cameras have been added to FLUOR for alignment and pupil plane imaging. Entirely new control/command software has been written for FLUOR which brings it into compliance with CHARA software standards. This allows for continued software upgrades and full remote operation capability. The new JouFLU instrument is now operating on sky and is expected to achieve accurate interferometric visibility amplitude measurements with 0.1 to 0.3% precision.

  7. Quantitative measurements of electromechanical response with a combined optical beam and interferometric atomic force microscope

    Science.gov (United States)

    Labuda, Aleksander; Proksch, Roger

    2015-06-01

    An ongoing challenge in atomic force microscope (AFM) experiments is the quantitative measurement of cantilever motion. The vast majority of AFMs use the optical beam deflection (OBD) method to infer the deflection of the cantilever. The OBD method is easy to implement, has impressive noise performance, and tends to be mechanically robust. However, it represents an indirect measurement of the cantilever displacement, since it is fundamentally an angular rather than a displacement measurement. Here, we demonstrate a metrological AFM that combines an OBD sensor with a laser Doppler vibrometer (LDV) to enable accurate measurements of the cantilever velocity and displacement. The OBD/LDV AFM allows a host of quantitative measurements to be performed, including in-situ measurements of cantilever oscillation modes in piezoresponse force microscopy. As an example application, we demonstrate how this instrument can be used for accurate quantification of piezoelectric sensitivity—a longstanding goal in the electromechanical community.

  8. JouFLU: upgrades to the fiber linked unit for optical recombination (FLUOR) interferometric beam combiner.

    Science.gov (United States)

    Scott, N. J.; Lhomé, E.; ten Brummelaar, T. A.; Coudé du Foresto, V.; Millan-Gabet, R.; Sturmann, J.; Sturmann, L.

    2014-07-01

    The Fiber Linked Unit for Optical Recombination (FLUOR) is a precision interferometric beam combiner operating at the CHARA Array on Mt. Wilson, CA. It has recently been upgraded as part of a mission known as "Jouvence of FLUOR" or JouFLU. As part of this program JouFLU has new mechanic stages and optical payloads, new alignment systems, and new command/control software. Furthermore, new capabilities have been implemented such as a Fourier Transform Spectrograph (FTS) mode and spectral dispersion mode. These upgrades provide new capabilities to JouFLU as well as improving statistical precision and increasing observing efficiency. With these new systems, measurements of interferometric visibility to the level of 0.1% precision are expected on targets as faint as 6th magnitude in the K band. Here we detail the upgrades of JouFLU and report on its current status.

  9. The Astronomical Tables of Moses Farissol Botarel

    OpenAIRE

    Goldstein, Bernard R.; Chabás, José

    2017-01-01

    Moses Farissol Botarel (Avignon, late fifteenth century) was an astronomer who wrote in Hebrew and continued various traditions that depended on astronomy in al-Andalus which, in turn, derived in large part from the zij of al-Battānī (Raqqa, d. 929). His astronomical tables are unusual in that they combine elements from the Parisian Alfonsine Tables with elements from the tables of Levi ben Gerson (Orange, France, d. 1344), Immanuel ben Jacob Bonfils (Tarascon, France, fl. 1350), and Jacob be...

  10. Astronomical Spectroscopy for Amateurs

    CERN Document Server

    Harrison, Ken M

    2011-01-01

    Astronomical Spectroscopy for Amateurs is a complete guide for amateur astronomers who are looking for a new challenge beyond astrophotography. The book provides a brief overview of the history and development of the spectroscope, then a short introduction to the theory of stellar spectra, including details on the necessary reference spectra required for instrument testing and spectral comparison. The various types of spectroscopes available to the amateur are then described. Later sections cover all aspects of setting up and using various types of commercially available and home-built spectroscopes, starting with basic transmission gratings and going through more complex models, all the way to the sophisticated Littrow design. The final part of the text is about practical spectroscope design and construction. This book uniquely brings together a collection of observing, analyzing, and processing hints and tips that will allow the amateur to build skills in preparing scientifically acceptable spectra data. It...

  11. Ancient Egyptian Astronomical Calander

    Science.gov (United States)

    Marshall, Patrice; Lodhi, M. A. K.

    2001-03-01

    In this paper, we discuss how certain astronomical concepts are related to the ancient Egyptian culture and their daily life. One of them is different ways of creating their calendar systems. The ancient Egyptian calendar seems to have quite a bit of its origin in astronomy and its development over the course of history. There is an important role played by events, as determined in the heavens, in developing their calendar system. Along with astronomical observations by the ancient people of Egypt, there were several outside cultures that helped develop their calendar system and Egyptian idea of how life was created on this planet, most notably the inclusion of the star Sirius in the constellation of Canis Major. We give a brief discussion of these influences. For the ancient Egyptians, the cycle of life and death is a concept that ties in with a calendar system used to determine daily events.

  12. Astronomical Research Using Virtual Observatories

    Directory of Open Access Journals (Sweden)

    M Tanaka

    2010-01-01

    Full Text Available The Virtual Observatory (VO for Astronomy is a framework that empowers astronomical research by providing standard methods to find, access, and utilize astronomical data archives distributed around the world. VO projects in the world have been strenuously developing VO software tools and/or portal systems. Interoperability among VO projects has been achieved with the VO standard protocols defined by the International Virtual Observatory Alliance (IVOA. As a result, VO technologies are now used in obtaining astronomical research results from a huge amount of data. We describe typical examples of astronomical research enabled by the astronomical VO, and describe how the VO technologies are used in the research.

  13. MMW/IR beam combiner with graphene IR window for MMW/IR compact range compound test

    Science.gov (United States)

    Chen, Dong; Li, Yanhong; Pang, Xudong; Zhu, Weihua; Wang, Liquan; Liu, Zhigang; Wang, Tailei; Zhu, Shouzheng

    2017-06-01

    A millimeter wave (MMW)/infrared (IR) beam combiner with a graphene IR window for the MMW/IR compact range (CR) compound test is creatively proposed with comprehensive analysis and simulation. Graphene is used as the IR window material to transfer the IR feed signal behind a perforated MMW CR reflector for it has the unique property of high IR transmissivity and high MMW conductivity. This research shows that graphene IR windows have better IR transmissivity than conducting inductive mesh IR windows when the beam combiner meets the MMW CR test demanding. Graphene IR windows also show a better MMW test bandwidth than dielectric IR windows. Meanwhile, the graphene IR window MMW/IR beam combiner has a circular aperture test zone with which it is sufficient to test a cylindrical unit under test according to the requirement.

  14. On Tokugawa Bakufu's astronomical officials

    Science.gov (United States)

    Yamada, Keiji

    2005-06-01

    Tokugawa Bakufu's astronomical office, established in 1684, is the post for calendar reform. The reform was conducted when the calendar did not predict peculiar celestial phenomena, such as solar or lunar eclipses. It was, so to speak, the theme of the ancient astronomy. From removal of the embargo on importing western science books in 1720, Japanese astronomers studied European astronomy and attempted to apply its knowledge to calendar making. Moreover, they knew the Copernican system and also faced several modern astronomical subjects. The French astronomer Lalande's work "ASTRONOMY" exerted particularly strong influence on astronomers. This paper overviews the activities of Paris observatory and French astronomers in the 17th and 18th centuries, and survey what modern astronomical subjects were. Finally, it sketches a role of the Edo observatory played in the Japanese cultural history.

  15. Astronomical database and VO-tools of Nikolaev Astronomical Observatory

    Science.gov (United States)

    Mazhaev, A. E.; Protsyuk, Yu. I.

    2010-05-01

    , search and visualisation of spectra, spectral energy distribution (SED) building, search of cross-correlation between objects in different catalogues, statistical data processing of large data volumes etc. The second part includes database of observations, accumulated in NAO, with access via a browser. The database has a common interface for searching of textual and graphical information concerning photographic and CCD observations. The database contains: textual information about 7437 plates as well as 2700 preview images in JPEG format with resolution of 300 DPI (dots per inch); textual information about 16660 CCD frames as well as 1100 preview images in JPEG format. Absent preview images will be added to the database as soon as they will be ready after plates scanning and CCD frames processing. The user has to define the equatorial coordinates of search centre, a search radius and a period of observations. Then he or she may also specify additional filters, such as: any combination of objects given separately for plates and CCD frames, output parameters for plates, telescope names for CCD observations. Results of search are generated in the form of two tables for photographic and CCD observations. To obtain access to the source images in FITS format with support of World Coordinate System (WCS), the user has to fill and submit electronic form given after the tables. The third part includes database of observations with access via a standalone application such as Aladin, which has been developed by Strasbourg Astronomical Data Centre. To obtain access to the database, the user has to perform a series of simple actions, which are described on a corresponding site page. Then he or she may get access to the database via a server selector of Aladin, which has a menu with wide range of image and catalogue servers located world wide, including two menu items for photographic and CCD observations of a NVO image server. The user has to define the equatorial coordinates of

  16. IEC 61267: Feasibility of type 1100 aluminium and a copper/aluminium combination for RQA beam qualities.

    Science.gov (United States)

    Leong, David L; Rainford, Louise; Zhao, Wei; Brennan, Patrick C

    2016-01-01

    In the course of performance acceptance testing, benchmarking or quality control of X-ray imaging systems, it is sometimes necessary to harden the X-ray beam spectrum. IEC 61267 specifies materials and methods to accomplish beam hardening and, unfortunately, requires the use of 99.9% pure aluminium (Alloy 1190) for the RQA beam quality, which is expensive and difficult to obtain. Less expensive and more readily available filters, such as Alloy 1100 (99.0% pure) aluminium and copper/aluminium combinations, have been used clinically to produce RQA series without rigorous scientific investigation to support their use. In this paper, simulation and experimental methods are developed to determine the differences in beam quality using Alloy 1190 and Alloy 1100. Additional simulation investigated copper/aluminium combinations to produce RQA5 and outputs from this simulation are verified with laboratory tests using different filter samples. The results of the study demonstrate that although Alloy 1100 produces a harder beam spectrum compared to Alloy 1190, it is a reasonable substitute. A combination filter of 0.5 mm copper and 2 mm aluminium produced a spectrum closer to that of Alloy 1190 than Alloy 1100 with the added benefits of lower exposures and lower batch variability. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  17. Application of digital image processing techniques to astronomical imagery 1977

    Science.gov (United States)

    Lorre, J. J.; Lynn, D. J.

    1978-01-01

    Nine specific techniques of combination of techniques developed for applying digital image processing technology to existing astronomical imagery are described. Photoproducts are included to illustrate the results of each of these investigations.

  18. Astronomical Instruments in India

    Science.gov (United States)

    Sarma, Sreeramula Rajeswara

    The earliest astronomical instruments used in India were the gnomon and the water clock. In the early seventh century, Brahmagupta described ten types of instruments, which were adopted by all subsequent writers with minor modifications. Contact with Islamic astronomy in the second millennium AD led to a radical change. Sanskrit texts began to lay emphasis on the importance of observational instruments. Exclusive texts on instruments were composed. Islamic instruments like the astrolabe were adopted and some new types of instruments were developed. Production and use of these traditional instruments continued, along with the cultivation of traditional astronomy, up to the end of the nineteenth century.

  19. Note: Determination of torsional spring constant of atomic force microscopy cantilevers: Combining normal spring constant and classical beam theory

    DEFF Research Database (Denmark)

    Álvarez-Asencio, R.; Thormann, Esben; Rutland, M.W.

    2013-01-01

    A technique has been developed for the calculation of torsional spring constants for AFM cantilevers based on the combination of the normal spring constant and plate/beam theory. It is easy to apply and allow the determination of torsional constants for stiff cantilevers where the thermal power...

  20. Pion Energy Reconstruction by the Local Hadronic Calibration Method with ATLAS Combined Test Beam 2004 data

    CERN Document Server

    Kulchitsky, Y; Khubua, J; Russakovich, N; Shigaev, V; Vinogradov, V

    2008-01-01

    The pion energy reconstruction by the local hadronic calibration method on the basis of the 2004 combined test beam data in the energy range 10 -- 350 GeV and $\\eta = 0.25$ is performed. In this method energies deposited in each cell are weighted. The weights are determined by the Monte Carlo simulation using Calibration Hits software. We have modified this method by applying cuts in weights. The obtained fractional energy resolution with the conventional method of determination of the energy deposit in the dead material between LAr and Tile calorimeters is $\\sigma/E = (67\\pm2)\\%/\\sqrt{E} \\oplus (3.9\\pm0.2)\\% \\oplus (95\\pm22)\\%/E$. This is about 1.5 times better than the results for the hadronic calibration method obtained by the Oxford-Stockholm group and slightly better than the H1 method results for CTB04 obtained by Pisa group. The energy linearity is within $\\pm$1\\%. We have determined the general normalization constant of 0.91 for which the mean value linearity for the weight cut of 1.05 is about 1. At ...

  1. Grigor Narekatsi's astronomical insights

    Science.gov (United States)

    Poghosyan, Samvel

    2015-07-01

    What stand out in the solid system of Gr. Narekatsi's naturalistic views are his astronomical insights on the material nature of light, its high speed and the Sun being composed of "material air". Especially surprising and fascinating are his views on stars and their clusters. What astronomers, including great Armenian academician V. Ambartsumian (scattering of stellar associations), would understand and prove with much difficulty thousand years later, Narekatsi predicted in the 10th century: "Stars appear and disappear untimely", "You who gather and scatter the speechless constellations, like a flock of sheep". Gr. Narekatsti's reformative views were manifested in all the spheres of the 10th century social life; he is a reformer of church life, great language constructor, innovator in literature and music, freethinker in philosophy and science. His ideology is the reflection of the 10th century Armenian Renaissance. During the 9th-10th centuries, great masses of Armenians, forced to migrate to the Balkans, took with them and spread reformative ideas. The forefather of the western science, which originated in the period of Reformation, is considered to be the great philosopher Nicholas of Cusa. The study of Gr. Narekatsti's logic and naturalistic views enables us to claim that Gr. Narekatsti is the great grandfather of European science.

  2. La Plata Astronomical Observatory

    Science.gov (United States)

    Forte, Juan Carlos; Cora, Sofia A.

    La Plata, the current capital city of the province of Buenos Aires, was founded on 19 November 1882 by governor Dardo Rocha, and built on an innovative design giving emphasis to the quality of the public space, official and educational buildings. The Astronomical Observatory was one of the first inhabitants of the main park of the city; its construction started in 1883 including two telescopes that ranked among the largest in the southern hemisphere at that time and also several instruments devoted to positional astronomy (e.g. a meridian circle and a zenith telescope). A dedicated effort has being invested during the last 15 years in order to recover some of the original instrumentation (kept in a small museum) as well as the distinctive architectural values. In 1905, the Observatory, the School of Agriculture and the Museum of Natural Sciences (one of the most important museums in South America) became part of the backbone of La Plata National University, an institution with a strong and distinctive profile in exact and natural sciences. The First School for Astronomy and Related Sciences had been harboured by the Observatory since 1935, and became the current Faculty of Astronomical and Geophysical Sciences in 1983. This last institution carries PhD programs and also a number of teaching activities at different levels. These activities are the roots of a strong connection of the Observatory with the city.

  3. Human perception of indoor environment generated by chilled ceiling combined with mixing ventilation or localised chilled beam under cooling mode

    DEFF Research Database (Denmark)

    Bolashikov, Zhecho Dimitrov; Nygaard, Linette; Uth, Simon C.

    2014-01-01

    Experiments with 24 subjects were performed to study and compare the human perception of the indoor environment under summer conditions generated by a chilled ceiling combined with overhead mixing ventilation and localised chilled beam. The experiments were performed in an experimental chamber (4....../s during the 20 min period of physical activity, when the occupant was not at the desk with the localised chilled beam, resulting in increase of the air temperature in the room. Subjects used questionnaires to answer on thermal sensation and acceptability, perceived air quality, air movement and SBS...

  4. Photon reconstruction in the ATLAS Inner Detector and Liquid Argon Barrel Calorimeter at the 2004 Combined Test Beam

    CERN Document Server

    Abat, E; Addy, T N; Adragna, P; Aharrouche, M; Ahmad, A; Akesson, T.P A; Aleksa, M; Alexa, C; Anderson, K; Andreazza, A; Anghinolfi, F; Antonaki, A; Arabidze, G; Arik, E; Atkinson, T; Baines, J; Baker, O K; Banfi, D; Baron, S; Barr, A J; Beccherle, R; Beck, H P; Belhorma, B; Bell, P J; Benchekroun, D; Benjamin, D P; Benslama, K; Bergeaas Kuutmann, E; Bernabeu, J; Bertelsen, H; Binet, S; Biscarat, C; Boldea, V; Bondarenko, V G; Boonekamp, M; Bosman, M; Bourdarios, C; Broklova, Z; Burckhart-Chromek, D; Bychkov, V; Callahan, J; Calvet, D; Canneri, M; Capeans Garrido, M; Caprini, M; Cardiel Sas, L; Carli, T; Carminati, L; Carvalho, J; Cascella, M; Castillo, M V; Catinaccio, A; Cauz, D; Cavalli, D; Cavalli-Sforza, M; Cavasinni, V; Cetin, S A; Chen, H; Cherkaoui, R; Chevalier, L; Chevallier, F; Chouridou, S; Ciobotaru, M; Citterio, M; Clark, A; Cleland, B; Cobal, M; Cogneras, E; Conde Muino, P; Consonni, M; Constantinescu, S; Cornelissen, T; Correard, S; Corso-Radu, A; Costa, G; Costa, M J; Costanzo, D; Cuneo, S; Cwetanski, P; Da Silva, D; Dam, M; Dameri, M; Danielsson, H O; Dannheim, D; Darbo, G; Davidek, T; De, K; Defay, P O; Dekhissi, B; Del Peso, J; Del Prete, T; Delmastro, M; Derue, F; Di Ciaccio, L; Di Girolamo, B; Dita, S; Dittus, F; Djama, F; Djobava, T; Dobos, D; Dobson, M; Dolgoshein, B A; Dotti, A; Drake, G; Drasal, Z; Dressnandt, N; Driouchi, C; Drohan, J; Ebenstein, W L; Eerola, P; Efthymiopoulos, I; Egorov, K; Eifert, T F; Einsweiler, K; El Kacimi, M; Elsing, M; Emelyanov, D; Escobar, C; Etienvre, A I; Fabich, A; Facius, K; Idrissi Fakhr-Eddine, A; Fanti, M; Farbin, A; Farthouat, P; Fassouliotis, D; Fayard, L; Febbraro, R; Fedin, O L; Fenyuk, A; Fergusson, D; Ferrari, P; Ferrari, R; Ferreira, B C; Ferrer, A; Ferrere, D; Filippini, G; Flick, T; Fournier, D; Francavilla, P; Francis, D; Froeschl, R; Froidevaux, D; Fullana, E; Gadomski, S; Gagliardi, G; Gagnon, P; Gallas, M; Gallop, B J; Gameiro, S; Gan, K K; Garcia, R; Garcia, C; Gavrilenko, I L; Gemme, C; Gerlach, P; Ghodbane, N; Giakoumopoulou, V; Giangiobbe, V; Giokaris, N; Glonti, G; Gottfert, T.; Golling, T; Gollub, N; Gomes, A; Gomez, M D; Gonzalez-Sevilla, S; Goodrick, M J; Gorfine, G; Gorini, B; Goujdami, D; Grahn, K J; Grenier, P; Grigalashvili, N; Grishkevich, Y; Grosse-Knetter, J; Gruwe, M; Guicheney, C; Gupta, A; Haeberli, C; Hartel, R.; Hajduk, Z; Hakobyan, H; Hance, M; Hansen, J D; Hansen, P H; Hara, K; Harvey, A., Jr; Hawkings, R J; Heinemann, F.E W; Henriques Correia, A; Henss, T; Hervas, L; Higon, E; Hill, J C; Hoffman, J; Hostachy, J Y; Hruska, I; Hubaut, F; Huegging, F; Hulsbergen, W; Hurwitz, M; Iconomidou-Fayard, L; Jansen, E; Jen-La Plante, I; Johansson, P.D C; Jon-And, K; Joos, M; Jorgensen, S; Joseph, J; Kaczmarska, A; Kado, M; Karyukhin, A; Kataoka, M; Kayumov, F; Kazarov, A; Keener, P T; Kekelidze, G D; Kerschen, N; Kersten, S; Khomich, A; Khoriauli, G; Khramov, E; Khristachev, A; Khubua, J; Kittelmann, T H; Klingenberg, R; Klinkby, E B; Kodys, P; Koffas, T; Kolos, S; Konovalov, S P; Konstantinidis, N; Kopikov, S; Korolkov, I; Kostyukhin, V; Kovalenko, S; Kowalski, T Z; Kruger, K.; Kramarenko, V; Kudin, L G; Kulchitsky, Y; Lacasta, C; Lafaye, R; Laforge, B; Lampl, W; Lanni, F; Laplace, S; Lari, T; Le Bihan, A C; Lechowski, M; Ledroit-Guillon, F; Lehmann, G; Leitner, R; Lelas, D; Lester, C G; Liang, Z; Lichard, P; Liebig, W; Lipniacka, A; Lokajicek, M; Louchard, L; Loureiro, K F; Lucotte, A; Luehring, F; Lund-Jensen, B; Lundberg, B; Ma, H; Mackeprang, R; Maio, A; Maleev, V P; Malek, F; Mandelli, L; Maneira, J; Mangin-Brinet, M; Manousakis, A; Mapelli, L; Marques, C; Marti i Garcia, S; Martin, F; Mathes, M; Mazzanti, M; McFarlane, K W; McPherson, R; Mchedlidze, G; Mehlhase, S; Meirosu, C; Meng, Z; Meroni, C; Mialkovski, V; Mikulec, B; Milstead, D; Minashvili, I; Mindur, B; Mitsou, V A; Moed, S; Monnier, E; Moorhead, G; Morettini, P; Morozov, S V; Mosidze, M; Mouraviev, S V; Moyse, E.W J; Munar, A; Myagkov, A; Nadtochi, A V; Nakamura, K; Nechaeva, P; Negri, A; Nemecek, S; Nessi, M; Nesterov, S Y; Newcomer, F M; Nikitine, I; Nikolaev, K; Nikolic-Audit, I; Ogren, H; Oh, S H; Oleshko, S B; Olszowska, J; Onofre, A; Padilla Aranda, C; Paganis, S; Pallin, D; Pantea, D; Paolone, V; Parodi, F; Parsons, J; Parzhitski, S; Pasqualucci, E; Passmore, S M; Pater, J; Patrichev, S; Peez, M; Perez Reale, V; Perini, L; Peshekhonov, V D; Petersen, J; Petersen, T C; Petti, R; Phillips, P W; Pilcher, J; Pina, J; Pinto, B; Podlyski, F; Poggioli, L; Poppleton, A; Poveda, J; Pralavorio, P; Pribyl, L; Price, M J; Prieur, D; Puigdengoles, C; Puzo, P; Ragusa, F; Rajagopalan, S; Reeves, K; Reisinger, I; Rembser, C; Bruckman de Renstrom, P.A.; Reznicek, P; Ridel, M; Risso, P; Riu, I; Robinson, D; Roda, C; Roe, S; Rohne, O.; Romaniouk, A; Rousseau, D; Rozanov, A; Ruiz, A; Rusakovich, N; Rust, D; Ryabov, Y F; Ryjov, V; Salto, O; Salvachua, B; Salzburger, A; Sandaker, H; Santamarina Rios, C.Santamarina; Santi, L; Santoni, C; Saraiva, J G; Sarri, F; Sauvage, G; Says, L P; Schaefer, M; Schegelsky, V A; Schiavi, C; Schieck, J; Schlager, G; Schlereth, J; Schmitt, C; Schultes, J; Schwemling, P; Schwindling, J; Seixas, J M; Seliverstov, D M; Serin, L; Sfyrla, A; Shalanda, N; Shaw, C; Shin, T; Shmeleva, A; Silva, J; Simion, S; Simonyan, M; Sloper, J E; Smirnov, S.Yu; Smirnova, L; Solans, C; Solodkov, A; Solovianov, O; Soloviev, I; Sosnovtsev, V V; Spano, F; Speckmayer, P; Stancu, S; Stanek, R; Starchenko, E; Straessner, A; Suchkov, S I; Suk, M; Szczygiel, R; Tarrade, F; Tartarelli, F; Tas, P; Tayalati, Y; Tegenfeldt, F; Teuscher, R; Thioye, M; Tikhomirov, V O; Timmermans, C.J.W P; Tisserant, S; Toczek, B; Tremblet, L; Troncon, C; Tsiareshka, P; Tyndel, M; Karagoz Unel, M.; Unal, G; Unel, G; Usai, G; Van Berg, R; Valero, A; Valkar, S; Valls, J A; Vandelli, W; Vannucci, F; Vartapetian, A; Vassilakopoulos, V I; Vasilyeva, L; Vazeille, F; Vernocchi, F; Vetter-Cole, Y; Vichou, I; Vinogradov, V; Virzi, J; Vivarelli, I; de Vivie, J B; Volpi, M; Vu Anh, T; Wang, C; Warren, M; Weber, J; Weber, M; Weidberg, A R; Weingarten, J; Wells, P S; Werner, P; Wheeler, S; Wiesmann, M; Wilkens, H; Williams, H H; Wingerter-Seez, I; Yasu, Y; Zaitsev, A; Zenin, A; Zenis, T; Zenonos, Z; Zhang, H; Zhelezko, A; Zhou, N

    2011-01-01

    The reconstruction of photons in the ATLAS detector is studied with data taken during the 2004 Combined Test Beam, where a full slice of the ATLAS detector was exposed to beams of particles of known energy at the CERN SPS. The results presented show significant differences in the longitudinal development of the electromagnetic shower between converted and unconverted photons as well as in the total measured energy. The potential to use the reconstructed converted photons as a means to precisely map the material of the tracker in front of the electromagnetic calorimeter is also considered. All results obtained are compared with a detailed Monte-Carlo simulation of the test-beam setup which is based on the same simulation and reconstruction tools as those used for the ATLAS detector itself.

  5. Photon reconstruction in the ATLAS Inner Detector and Liquid Argon Barrel Calorimeter at the 2004 Combined Test Beam

    Science.gov (United States)

    Abat, E.; Abdallah, J. M.; Addy, T. N.; Adragna, P.; Aharrouche, M.; Ahmad, A.; Akesson, T. P. A.; Aleksa, M.; Alexa, C.; Anderson, K.; Andreazza, A.; Anghinolfi, F.; Antonaki, A.; Arabidze, G.; Arik, E.; Atkinson, T.; Baines, J.; Baker, O. K.; Banfi, D.; Baron, S.; Barr, A. J.; Beccherle, R.; Beck, H. P.; Belhorma, B.; Bell, P. J.; Benchekroun, D.; Benjamin, D. P.; Benslama, K.; Bergeaas Kuutmann, E.; Bernabeu, J.; Bertelsen, H.; Binet, S.; Biscarat, C.; Boldea, V.; Bondarenko, V. G.; Boonekamp, M.; Bosman, M.; Bourdarios, C.; Broklova, Z.; Burckhart Chromek, D.; Bychkov, V.; Callahan, J.; Calvet, D.; Canneri, M.; Capeáns Garrido, M.; Caprini, M.; Cardiel Sas, L.; Carli, T.; Carminati, L.; Carvalho, J.; Cascella, M.; Castillo, M. V.; Catinaccio, A.; Cauz, D.; Cavalli, D.; Cavalli Sforza, M.; Cavasinni, V.; Cetin, S. A.; Chen, H.; Cherkaoui, R.; Chevalier, L.; Chevallier, F.; Chouridou, S.; Ciobotaru, M.; Citterio, M.; Clark, A.; Cleland, B.; Cobal, M.; Cogneras, E.; Conde Muino, P.; Consonni, M.; Constantinescu, S.; Cornelissen, T.; Correard, S.; Corso Radu, A.; Costa, G.; Costa, M. J.; Costanzo, D.; Cuneo, S.; Cwetanski, P.; Da Silva, D.; Dam, M.; Dameri, M.; Danielsson, H. O.; Dannheim, D.; Darbo, G.; Davidek, T.; De, K.; Defay, P. O.; Dekhissi, B.; Del Peso, J.; Del Prete, T.; Delmastro, M.; Derue, F.; Di Ciaccio, L.; Di Girolamo, B.; Dita, S.; Dittus, F.; Djama, F.; Djobava, T.; Dobos, D.; Dobson, M.; Dolgoshein, B. A.; Dotti, A.; Drake, G.; Drasal, Z.; Dressnandt, N.; Driouchi, C.; Drohan, J.; Ebenstein, W. L.; Eerola, P.; Efthymiopoulos, I.; Egorov, K.; Eifert, T. F.; Einsweiler, K.; El Kacimi, M.; Elsing, M.; Emelyanov, D.; Escobar, C.; Etienvre, A. I.; Fabich, A.; Facius, K.; Fakhr-Edine, A. I.; Fanti, M.; Farbin, A.; Farthouat, P.; Fassouliotis, D.; Fayard, L.; Febbraro, R.; Fedin, O. L.; Fenyuk, A.; Fergusson, D.; Ferrari, P.; Ferrari, R.; Ferreira, B. C.; Ferrer, A.; Ferrere, D.; Filippini, G.; Flick, T.; Fournier, D.; Francavilla, P.; Francis, D.; Froeschl, R.; Froidevaux, D.; Fullana, E.; Gadomski, S.; Gagliardi, G.; Gagnon, P.; Gallas, M.; Gallop, B. J.; Gameiro, S.; Gan, K. K.; Garcia, R.; Garcia, C.; Gavrilenko, I. L.; Gemme, C.; Gerlach, P.; Ghodbane, N.; Giakoumopoulou, V.; Giangiobbe, V.; Giokaris, N.; Glonti, G.; Goettfert, T.; Golling, T.; Gollub, N.; Gomes, A.; Gomez, M. D.; Gonzalez-Sevilla, S.; Goodrick, M. J.; Gorfine, G.; Gorini, B.; Goujdami, D.; Grahn, K.-J.; Grenier, P.; Grigalashvili, N.; Grishkevich, Y.; Grosse-Knetter, J.; Gruwe, M.; Guicheney, C.; Gupta, A.; Haeberli, C.; Haertel, R.; Hajduk, Z.; Hakobyan, H.; Hance, M.; Hansen, J. D.; Hansen, P. H.; Hara, K.; Harvey, A., Jr.; Hawkings, R. J.; Heinemann, F. E. W.; Henriques Correia, A.; Henss, T.; Hervas, L.; Higon, E.; Hill, J. C.; Hoffman, J.; Hostachy, J. Y.; Hruska, I.; Hubaut, F.; Huegging, F.; Hulsbergen, W.; Hurwitz, M.; Iconomidou-Fayard, L.; Jansen, E.; Jen-La Plante, I.; Johansson, P. D. C.; Jon-And, K.; Joos, M.; Jorgensen, S.; Joseph, J.; Kaczmarska, A.; Kado, M.; Karyukhin, A.; Kataoka, M.; Kayumov, F.; Kazarov, A.; Keener, P. T.; Kekelidze, G. D.; Kerschen, N.; Kersten, S.; Khomich, A.; Khoriauli, G.; Khramov, E.; Khristachev, A.; Khubua, J.; Kittelmann, T. H.; Klingenberg, R.; Klinkby, E. B.; Kodys, P.; Koffas, T.; Kolos, S.; Konovalov, S. P.; Konstantinidis, N.; Kopikov, S.; Korolkov, I.; Kostyukhin, V.; Kovalenko, S.; Kowalski, T. Z.; Krüger, K.; Kramarenko, V.; Kudin, L. G.; Kulchitsky, Y.; Lacasta, C.; Lafaye, R.; Laforge, B.; Lampl, W.; Lanni, F.; Laplace, S.; Lari, T.; Le Bihan, A.-C.; Lechowski, M.; Ledroit-Guillon, F.; Lehmann, G.; Leitner, R.; Lelas, D.; Lester, C. G.; Liang, Z.; Lichard, P.; Liebig, W.; Lipniacka, A.; Lokajicek, M.; Louchard, L.; Loureiro, K. F.; Lucotte, A.; Luehring, F.; Lund-Jensen, B.; Lundberg, B.; Ma, H.; Mackeprang, R.; Maio, A.; Maleev, V. P.; Malek, F.; Mandelli, L.; Maneira, J.; Mangin-Brinet, M.; Manousakis, A.; Mapelli, L.; Marques, C.; Garcia, S. Marti i.; Martin, F.; Mathes, M.; Mazzanti, M.; McFarlane, K. W.; McPherson, R.; Mchedlidze, G.; Mehlhase, S.; Meirosu, C.; Meng, Z.; Meroni, C.; Mialkovski, V.; Mikulec, B.; Milstead, D.; Minashvili, I.; Mindur, B.; Mitsou, V. A.; Moed, S.; Monnier, E.; Moorhead, G.; Morettini, P.; Morozov, S. V.; Mosidze, M.; Mouraviev, S. V.; Moyse, E. W. J.; Munar, A.; Myagkov, A.; Nadtochi, A. V.; Nakamura, K.; Nechaeva, P.; Negri, A.; Nemecek, S.; Nessi, M.; Nesterov, S. Y.; Newcomer, F. M.; Nikitine, I.; Nikolaev, K.; Nikolic-Audit, I.; Ogren, H.; Oh, S. H.; Oleshko, S. B.; Olszowska, J.; Onofre, A.; Padilla Aranda, C.; Paganis, S.; Pallin, D.; Pantea, D.; Paolone, V.; Parodi, F.; Parsons, J.; Parzhitskiy, S.; Pasqualucci, E.; Passmored, S. M.; Pater, J.; Patrichev, S.; Peez, M.; Perez Reale, V.; Perini, L.; Peshekhonov, V. D.; Petersen, J.; Petersen, T. C.; Petti, R.; Phillips, P. W.; Pilcher, J.; Pina, J.; Pinto, B.; Podlyski, F.; Poggioli, L.; Poppleton, A.; Poveda, J.; Pralavorio, P.; Pribyl, L.; Price, M. J.; Prieur, D.; Puigdengoles, C.; Puzo, P.; Ragusa, F.; Rajagopalan, S.; Reeves, K.; Reisinger, I.; Rembser, C.; Bruckman de Renstrom, P. A.; Reznicek, P.; Ridel, M.; Risso, P.; Riu, I.; Robinson, D.; Roda, C.; Roe, S.; Røhne, O.; Romaniouk, A.; Rousseau, D.; Rozanov, A.; Ruiz, A.; Rusakovich, N.; Rust, D.; Ryabov, Y. F.; Ryjov, V.; Salto, O.; Salvachua, B.; Salzburger, A.; Sandaker, H.; Santamarina Rios, C.; Santi, L.; Santoni, C.; Saraiva, J. G.; Sarri, F.; Sauvage, G.; Says, L. P.; Schaefer, M.; Schegelsky, V. A.; Schiavi, C.; Schieck, J.; Schlager, G.; Schlereth, J.; Schmitt, C.; Schultes, J.; Schwemling, P.; Schwindling, J.; Seixas, J. M.; Seliverstov, D. M.; Serin, L.; Sfyrla, A.; Shalanda, N.; Shaw, C.; Shin, T.; Shmeleva, A.; Silva, J.; Simion, S.; Simonyan, M.; Sloper, J. E.; Smirnov, S. Yu; Smirnova, L.; Solans, C.; Solodkov, A.; Solovianov, O.; Soloviev, I.; Sosnovtsev, V. V.; Spanò, F.; Speckmayer, P.; Stancu, S.; Stanek, R.; Starchenko, E.; Straessner, A.; Suchkov, S. I.; Suk, M.; Szczygiel, R.; Tarrade, F.; Tartarelli, F.; Tas, P.; Tayalati, Y.; Tegenfeldt, F.; Teuscher, R.; Thioye, M.; Tikhomirov, V. O.; Timmermans, C. J. W. P.; Tisserant, S.; Toczek, B.; Tremblet, L.; Troncon, C.; Tsiareshka, P.; Tyndel, M.; Karagoez Unel, M.; Unal, G.; Unel, G.; Usai, G.; Van Berg, R.; Valero, A.; Valkar, S.; Valls, J. A.; Vandelli, W.; Vannucci, F.; Vartapetian, A.; Vassilakopoulos, V. I.; Vasilyeva, L.; Vazeille, F.; Vernocchi, F.; Vetter-Cole, Y.; Vichou, I.; Vinogradov, V.; Virzi, J.; Vivarelli, I.; de Vivie, J. B.; Volpi, M.; Anh, T. Vu; Wang, C.; Warren, M.; Weber, J.; Weber, M.; Weidberg, A. R.; Weingarten, J.; Wells, P. S.; Werner, P.; Wheeler, S.; Wiessmann, M.; Wilkens, H.; Williams, H. H.; Wingerter-Seez, I.; Yasu, Y.; Zaitsev, A.; Zenin, A.; Zenis, T.; Zenonos, Z.; Zhang, H.; Zhelezko, A.; Zhou, N.

    2011-04-01

    The reconstruction of photons in the ATLAS detector is studied with data taken during the 2004 Combined Test Beam, where a full slice of the ATLAS detector was exposed to beams of particles of known energy at the CERN SPS. The results presented show significant differences in the longitudinal development of the electromagnetic shower between converted and unconverted photons as well as in the total measured energy. The potential to use the reconstructed converted photons as a means to precisely map the material of the tracker in front of the electromagnetic calorimeter is also considered. All results obtained are compared with a detailed Monte-Carlo simulation of the test-beam setup which is based on the same simulation and reconstruction tools as those used for the ATLAS detector itself.

  6. Combined hydrogen and lithium beam emission spectroscopy observation system for Korea Superconducting Tokamak Advanced Research

    Energy Technology Data Exchange (ETDEWEB)

    Lampert, M. [Wigner RCP, Euratom Association-HAS, Budapest (Hungary); BME NTI, Budapest (Hungary); Anda, G.; Réfy, D.; Zoletnik, S. [Wigner RCP, Euratom Association-HAS, Budapest (Hungary); Czopf, A.; Erdei, G. [Department of Atomic Physics, BME IOP, Budapest (Hungary); Guszejnov, D.; Kovácsik, Á.; Pokol, G. I. [BME NTI, Budapest (Hungary); Nam, Y. U. [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2015-07-15

    A novel beam emission spectroscopy observation system was designed, built, and installed onto the Korea Superconducting Tokamak Advanced Research tokamak. The system is designed in a way to be capable of measuring beam emission either from a heating deuterium or from a diagnostic lithium beam. The two beams have somewhat complementary capabilities: edge density profile and turbulence measurement with the lithium beam and two dimensional turbulence measurement with the heating beam. Two detectors can be used in parallel: a CMOS camera provides overview of the scene and lithium beam light intensity distribution at maximum few hundred Hz frame rate, while a 4 × 16 pixel avalanche photo-diode (APD) camera gives 500 kHz bandwidth data from a 4 cm × 16 cm region. The optics use direct imaging through lenses and mirrors from the observation window to the detectors, thus avoid the use of costly and inflexible fiber guides. Remotely controlled mechanisms allow adjustment of the APD camera’s measurement location on a shot-to-shot basis, while temperature stabilized filter holders provide selection of either the Doppler shifted deuterium alpha or lithium resonance line. The capabilities of the system are illustrated by measurements of basic plasma turbulence properties.

  7. East Asian astronomical records

    Science.gov (United States)

    Stephenson, F. Richard

    Chinese, Japanese and Korean celestial observations have made major contributions to Applied Historical Astronomy, especially in the study of supernovae, comets, Earth's rotation (using eclipses) and solar variability (via sunspots and aurorae). Few original texts now survive; almost all extant records exist only in printed versions, often with the loss of much detail. The earliest Chinese astronomical observations extend back to before 1000 BC. However, fairly systematic records are only available since 200 BC - and even these have suffered losses through wars, etc. By around AD 800, many independent observations are available from Japan and Korea and these provide a valuable supplement to the Chinese data. Throughout East Asia dates were expressed in terms of a luni-solar calendar and conversion to the Julian or Gregorian calendar can be readily effected.

  8. pwkit: Astronomical utilities in Python

    Science.gov (United States)

    Williams, Peter K. G.; Clavel, Maïca; Newton, Elisabeth; Ryzhkov, Denis

    2017-04-01

    pwkit is a collection of miscellaneous astronomical utilities in Python, with an emphasis on radio astronomy, reading and writing various data formats, and convenient command-line utilities. Utilities include basic astronomical calculations, data visualization tools such as mapping arbitrary data to color scales and tracing contours, and data input and output utilities such as streaming output from other programs.

  9. SU-E-T-279: A Novel Electron-Beam Combined with Magnetic Field Application for Radiotherapy.

    Science.gov (United States)

    Alezra, D; Nardi, E; Koren, S; Bragilovski, D; Orion, I

    2012-06-01

    The new beam and delivery system consists of an electron accelerator and a system of magnets (one or more). Introducing a transverse magnetic field in and near the tumor, causes the electrons to spiral in this region, thereby producing an effective peak in the depth dose distribution, within the tumor volume. Although the basic idea is not new, we suggest here for the first time, a viable as well as a workable, magnetic field configuration, which in addition to focusing the beam does not interfere with its propagation to the target. The electron accelerator: can be a linear accelerator or any other type electron accelerator, capable of producing different electron energies for different depths and dose absorption accumulation. The Field size can be as small as a pencil beam and as big as any of the other standard field sizes that are used in radiotherapy. The scatter filter can be used or removed. The dose rate accumulation can be as higher as possible.The magnets are able to produce magnetic fields. The order, direction, width, place, shape and number of the magnetic fields define the shape and the Percentage Depth Dose (PDD) curve of the electron beam. Prototypes were successfully tested by means of computer simulation, using:COMSOL-Multiphsics for magnetic fields calculations. FLUKA package, for electron beam MC simulation. Our results suggest that by using an electron beam at different energies, combined with magnetic fields, we could modify the delivered dose. This is caused by manipulating the electron motion via the Lorentz force. The applied magnetic field, will focus the electron beam at a given depth and deposit the energy in a given volume and depth, where otherwise the electron energy will have spread deeper. The direction and magnitude of the magnetic fields will prevent the scattering of the electron beam and its absorption in remote volumes. In practice, we get a pseudo Bragg peak depth dose distribution, applying a relatively low cost system. The

  10. Combined electron-beam and adsorption purification of water from mercury and chromium using materials of vegetable origin as sorbents

    Science.gov (United States)

    Ponomarev, A. V.; Bludenko, A. V.; Makarov, I. E.; Pikaev, A. K.; Kyung Kim, Duk; Kim, Yuri; Han, Bumsoo

    1997-04-01

    Combined electron-beam and adsorption method of purification of water from Hg(II) and Cr(VI) using materials of vegetable origin as sorbents was developed. It consists in the addition of materials of vegetable origin (e.g. cellulose, carboxymethyl cellulose, starch, and wheat flour) into water, subsequent electron-beam irradiation, sedimentation and filtration of additives with captured Hg(II) or Cr(VI). The method is based on the synergistic effect of the combined action of irradiation and sorbent. The best results were obtained with the wheat flour. For example, the addition of 25 mg/I of the flour to the water containing 1 mg/I Hg(II) and irradiation with dose 1.1 kGy upon bubbling inert gas through the system led to the 98% removal of the pollutant. The possible mechanism of the processes causing the purification of water is discussed.

  11. Re-irradiation using proton beam therapy combined with weekly intra-arterial chemotherapy for recurrent oral cancer.

    Science.gov (United States)

    Hayashi, Yuichiro; Nakamura, Tatsuya; Mitsudo, Kenji; Kimura, Kanako; Yamaguchi, Hisashi; Ono, Takashi; Azami, Yusuke; Takayama, Kanako; Hirose, Katsumi; Yabuuchi, Tomonori; Suzuki, Motohisa; Hatayama, Yoshiomi; Kikuchi, Yasuhiro; Wada, Hitoshi; Fuwa, Nobukazu; Hareyama, Masato; Tohnai, Iwai

    2017-10-01

    The purpose of this study was to clarify the efficacy and toxicities of re-irradiation using proton beam therapy combined with weekly intra-arterial chemotherapy for recurrent oral cancer. Between October 2009 and July 2014, 34 patients who had recurrent oral cancer were treated by proton beam therapy combined with intra-arterial infusion chemotherapy at the Southern Tohoku Proton Therapy Center, Japan. For all patients, the median follow-up was 25 months (range, 3-77 months). After treatment, 22 patients (65%) achieved a complete response, and 12 patients (35%) achieved a partial response at the primary tumor site. One-year and 2-year overall survival (OS) rates were 62% and 42%, respectively. One-year and 2-year LC rates were 77% and 60%, respectively. No treatment-related deaths were observed during the treatment and follow-up periods. Re-irradiation using proton beam therapy combined with weekly intra-arterial chemotherapy improved OS and local control rates compared with other treatment modalities and could become a new treatment modality for patients with recurrent oral cancer. © 2016 John Wiley & Sons Australia, Ltd.

  12. Philosophy for the Creation of Astronomical Images

    Science.gov (United States)

    Rector, T.; Levay, Z. G.; Frattare, L. M.; English, J.; Pu'Uohau-Pummill, K.

    2005-12-01

    The quality of modern astronomical data, the power of modern computers and the agility of current image-processing software enable the creation of high-quality images in a purely digital form. The combination of these technological advancements has created a new ability to make colour astronomical images. These programs use a layering metaphor that allows for an unlimited number of astronomical datasets to be combined in any desired colour scheme, creating an immense parameter space to be explored. A philosophy is presented on how to use scaling, colour and composition to create images that simultaneously highlight scientific detail and are aesthetically appealing. This philosophy is necessary because most datasets do not correspond to the wavelength range of sensitivity of the human eye. The use of visual grammar, defined as the elements that affect the interpretation of an image, can maximize the richness and detail in an image while maintaining scientific accuracy. By properly using visual grammar, one can imply qualities that a two-dimensional image cannot show intrinsically, such as depth, motion and energy. In addition, composition can be used to engage viewers and keep them interested for a longer period of time. The use of these techniques can result in a striking image that will effectively convey the science within the image to scientists and to the public. Details of the pictorial examples used are presented in the conference web-proceedings and webcast.

  13. Astrophotonics: a new era for astronomical instruments.

    Science.gov (United States)

    Bland-Hawthorn, Joss; Kern, Pierre

    2009-02-02

    Astrophotonics lies at the interface of astronomy and photonics. This burgeoning field has emerged over the past decade in response to the increasing demands of astronomical instrumentation. Early successes include: (i) planar waveguides to combine signals from widely spaced telescopes in stellar interferometry; (ii) frequency combs for ultra-high precision spectroscopy to detect planets around nearby stars; (iii) ultra-broadband fibre Bragg gratings to suppress unwanted background; (iv) photonic lanterns that allow single-mode behaviour within a multimode fibre; (v) planar waveguides to miniaturize astronomical spectrographs; (vi) large mode area fibres to generate artificial stars in the upper atmosphere for adaptive optics correction; (vii) liquid crystal polymers in optical vortex coronographs and adaptive optics systems. Astrophotonics, a field that has already created new photonic capabilities, is now extending its reach down to the Rayleigh scattering limit at ultraviolet wavelengths, and out to mid infrared wavelengths beyond 2500 nm.

  14. Beam steering for circular switched parasitic arrays using a combinational approach

    CSIR Research Space (South Africa)

    Mofolo, ROM

    2011-09-01

    Full Text Available because of the array symmetry advantage [12]. This beam steering approach produces limited beam steering resolution. The On/Off RF switches are mostly used in the design of SPA antennas [14] to electronically switch the parasitic elements between... and isolated from the ground plane using a thin sheet of insulation material. III. SYSTEM MODEL The system studied in this paper is a single ring circular switched parasitic array antenna with a total of five elements (N=5): one central active element...

  15. Two-color above threshold ionization of atoms and ions in XUV Bessel beams and combined with intense laser light

    CERN Document Server

    Seipt, D; Surzhykov, A; Fritzsche, S

    2016-01-01

    The two-color above-threshold ionization (ATI) of atoms and ions is investigated for a vortex Bessel beam in the presence of a strong near-infrared (NIR) light field. While the photoionization is caused by the photons from the weak but extreme ultra-violet (XUV) vortex Bessel beam, the energy and angular distribution of the photoelectrons and their sideband structure are affected by the plane-wave NIR field. We here explore the energy spectra and angular emission of the photoelectrons in such two-color fields as a function of the size and location of the target (atoms) with regard to the beam axis. In addition, analogue to the circular dichroism in typical two-color ATI experiments with circularly polarized light, we define and discuss seven different dichroism signals for such vortex Bessel beams that arise from the various combinations of the orbital and spin angular momenta of the two light fields. For localized targets, it is found that these dichroism signals strongly depend on the size and position of t...

  16. Optimizing significance testing of astronomical forcing in cyclostratigraphy

    Science.gov (United States)

    Kemp, David B.

    2016-12-01

    The recognition of astronomically forced (Milankovitch) climate cycles in geological archives marked a major advance in Earth science, revealing a heartbeat within the climate system of general importance and key utility. Power spectral analysis is the primary tool used to facilitate identification of astronomical cycles in stratigraphic data, but commonly employed methods for testing the statistical significance of relatively high narrow-band variance of potential astronomical origin in spectra have been criticized for inadequately balancing the respective probabilities of type I (false positive) and type II (false negative) errors. This has led to suggestions that the importance of astronomical forcing in Earth history is overstated. It can be readily demonstrated, however, that the imperfect nature of the stratigraphic record and the quasiperiodicity of astronomical cycles sets an upper limit on the attainable significance of astronomical signals. Optimized significance testing is that which minimizes the combined probability of type I and type II errors. Numerical simulations of stratigraphically preserved astronomical signals suggest that optimum significance levels at which to reject a null hypothesis of no astronomical forcing are between 0.01 and 0.001 (i.e., 99-99.9% confidence level). This is lower than commonly employed in the literature (90-99% confidence levels). Nevertheless, in consonance with the emergent view from other scientific disciplines, fixed-value null hypothesis significance testing of power spectra is implicitly ill suited to demonstrating astronomical forcing, and the use of spectral analysis remains a difficult and subjective endeavor in the absence of additional supporting evidence.

  17. Using commercial amateur astronomical spectrographs

    CERN Document Server

    Hopkins, Jeffrey L

    2014-01-01

    Amateur astronomers interested in learning more about astronomical spectroscopy now have the guide they need. It provides detailed information about how to get started inexpensively with low-resolution spectroscopy, and then how to move on to more advanced  high-resolution spectroscopy. Uniquely, the instructions concentrate very much on the practical aspects of using commercially-available spectroscopes, rather than simply explaining how spectroscopes work. The book includes a clear explanation of the laboratory theory behind astronomical spectrographs, and goes on to extensively cover the practical application of astronomical spectroscopy in detail. Four popular and reasonably-priced commercially available diffraction grating spectrographs are used as examples. The first is a low-resolution transmission diffraction grating, the Star Analyser spectrograph. The second is an inexpensive fiber optic coupled bench spectrograph that can be used to learn more about spectroscopy. The third is a newcomer, the ALPY ...

  18. Astronomical Significance of Ancient Monuments

    Science.gov (United States)

    Simonia, I.

    2011-06-01

    Astronomical significance of Gokhnari megalithic monument (eastern Georgia) is considered. Possible connection of Amirani ancient legend with Gokhnari monument is discussed. Concepts of starry practicality and solar stations are proposed.

  19. Annotations of a Public Astronomer

    Science.gov (United States)

    Adamo, A.

    2011-06-01

    Angelo Adamo is an Italian astronomer and artist interested in inspiring people with scientifically-based tales. He has recently published two illustrated books exploring the relationships between mankind and cosmos through physics, art, literature, music, cartoons, and movies.

  20. A Layer Correlation Technique for Pion Energy Calibration at the 2004 ATLAS Combined Beam Test (Conference record)

    CERN Document Server

    Grahn, K-J; The ATLAS collaboration

    2009-01-01

    A new method for calibrating the hadron response of a segmented calorimeter is developed. It is based on a principal component analysis of the calorimeter layer energy deposits, exploiting longitudinal shower development information to improve the measured energy resolution. Corrections for invisible hadronic energy and energy lost in dead material in front of and between the ATLAS calorimeters were calculated with simulated Geant4 Monte Carlo events and used to reconstruct the energy of pions impinging on the calorimeters during the 2004 Barrel Combined Beam Test at the CERN H8 area. For pion beams with energies between 20 and 180 GeV, the particle energy is reconstructed within 3% and the energy resolution is improved by about 20% compared to the electromagnetic scale.

  1. Respiratory gated beam delivery cannot facilitate margin reduction, unless combined with respiratory correlated image guidance

    DEFF Research Database (Denmark)

    Korreman, S.S.; Boyer, A.L.; Juhler-Nøttrup, Trine

    2008-01-01

    PURPOSE/OBJECTIVE: In radiotherapy of targets moving with respiration, beam gating is offered as a means of reducing the target motion. The purpose of this study is to evaluate the safe magnitude of margin reduction for respiratory gated beam delivery. MATERIALS/METHODS: The study is based on data...... for 17 lung cancer patients in separate protocols at Rigshospitalet and Stanford Cancer Center. Respiratory curves for external optical markers and implanted fiducials were collected using equipment based on the RPM system (Varian Medical Systems). A total of 861 respiratory curves represented external...... measurements over 30 fraction treatment courses for 10 patients, and synchronous external/internal measurements in single sessions for seven patients. Variations in respiratory amplitude (simulated coaching) and external/internal phase shifts were simulated by perturbation with realistic values. Variations...

  2. Care of astronomical telescopes and accessories a manual for the astronomical observer and amateur telescope maker

    CERN Document Server

    Pepin, M Barlow

    2005-01-01

    Commercially-made astronomical telescopes are better and less expensive than ever before, and their optical and mechanical performance can be superb. When a good-quality telescope fails to perform as well as it might, the reason is quite probably that it needs a little care and attention! Here is a complete guide for anyone who wants to understand more than just the basics of astronomical telescopes and accessories, and how to maintain them in the peak of condition. The latest on safely adjusting, cleaning, and maintaining your equipment is combined with thoroughly updated methods from the old masters. Here, too, are details of choosing new and used optics and accessories, along with enhancements you can make to extend their versatility and useful lifetime. This book is for you. Really. Looking after an astronomical telescope isn't only for the experts - although there are some things that only an expert should attempt - and every serious amateur astronomer will find invaluable information here, gleaned from ...

  3. Enhanced radar precipitation estimates using a combined clutter and beam blockage correction technique

    Directory of Open Access Journals (Sweden)

    A. Fornasiero

    2006-01-01

    Full Text Available Weather radar observations are currently the most reliable method for remote sensing of precipitation. However, a number of factors affect the quality of radar observations and may limit seriously automated quantitative applications of radar precipitation estimates such as those required in Numerical Weather Prediction (NWP data assimilation or in hydrological models. In this paper, a technique to correct two different problems typically present in radar data is presented and evaluated. The aspects dealt with are non-precipitating echoes – caused either by permanent ground clutter or by anomalous propagation of the radar beam (anaprop echoes – and also topographical beam blockage. The correction technique is based in the computation of realistic beam propagation trajectories based upon recent radiosonde observations instead of assuming standard radio propagation conditions. The correction consists of three different steps: 1 calculation of a Dynamic Elevation Map which provides the minimum clutter-free antenna elevation for each pixel within the radar coverage; 2 correction for residual anaprop, checking the vertical reflectivity gradients within the radar volume; and 3 topographical beam blockage estimation and correction using a geometric optics approach. The technique is evaluated with four case studies in the region of the Po Valley (N Italy using a C-band Doppler radar and a network of raingauges providing hourly precipitation measurements. The case studies cover different seasons, different radio propagation conditions and also stratiform and convective precipitation type events. After applying the proposed correction, a comparison of the radar precipitation estimates with raingauges indicates a general reduction in both the root mean squared error and the fractional error variance indicating the efficiency and robustness of the procedure. Moreover, the technique presented is not computationally expensive so it seems well suited to be

  4. Flexural Behaviour of Combined FA/GGBFS Geopolymer Concrete Beams after Exposure to Elevated Temperatures

    OpenAIRE

    Jun-ru Ren; Hui-guo Chen; Tao Sun; Hao Song; Miao-shuo Wang

    2017-01-01

    As a promising alternative to OPC concrete, geopolymer concrete has been investigated and has demonstrated superior mechanical performance. Studying the thermal behaviour on the scale of a structural element is significant for introducing a new material to engineering applications. Four geopolymer concrete beams and four OPC concrete counterparts with the same reinforcement structure and similar concrete strength were subjected to three different heating cases at the rate of ISO834. The exper...

  5. X-ray Interferometry with Transmissive Beam Combiners for Ultra-High Angular Resolution Astronomy

    Science.gov (United States)

    Skinner, G. K.; Krismanic, John F.

    2009-01-01

    Abstract Interferometry provides one of the possible routes to ultra-high angular resolution for X-ray and gamma-ray astronomy. Sub-micro-arc-second angular resolution, necessary to achieve objectives such as imaging the regions around the event horizon of a super-massive black hole at the center of an active galaxy, can be achieved if beams from parts of the incoming wavefront separated by 100s of meters can be stably and accurately brought together at small angles. One way of achieving this is by using grazing incidence mirrors. We here investigate an alternative approach in which the beams are recombined by optical elements working in transmission. It is shown that the use of diffractive elements is a particularly attractive option. We report experimental results from a simple 2-beam interferometer using a low-cost commercially available profiled film as the diffractive elements. A rotationally symmetric filled (or mostly filled) aperture variant of such an interferometer, equivalent to an X-ray axicon, is shown to offer a much wider bandpass than either a Phase Fresnel Lens (PFL) or a PFL with a refractive lens in an achromatic pair. Simulations of an example system are presented.

  6. The New Amateur Astronomer

    Science.gov (United States)

    Mobberley, Martin

    Amateur astronomy has changed beyond recognition in less than two decades. The reason is, of course, technology. Affordable high-quality telescopes, computer-controlled 'go to' mountings, autoguiders, CCD cameras, video, and (as always) computers and the Internet, are just a few of the advances that have revolutionized astronomy for the twenty-first century. Martin Mobberley first looks at the basics before going into an in-depth study of what’s available commercially. He then moves on to the revolutionary possibilities that are open to amateurs, from imaging, through spectroscopy and photometry, to patrolling for near-earth objects - the search for comets and asteroids that may come close to, or even hit, the earth. The New Amateur Astronomer is a road map of the new astronomy, equally suitable for newcomers who want an introduction, or old hands who need to keep abreast of innovations. From the reviews: "This is one of several dozen books in Patrick Moore's "Practical Astronomy" series. Amid this large family, Mobberley finds his niche: the beginning high-tech amateur. The book's first half discusses equipment: computer-driven telescopes, CCD cameras, imaging processing software, etc. This market is changing every bit as rapidly as the computer world, so these details will be current for only a year or two. The rest of the book offers an overview of scientific projects that serious amateurs are carrying out these days. Throughout, basic formulas and technical terms are provided as needed, without formal derivations. An appendix with useful references and Web sites is also included. Readers will need more than this book if they are considering a plunge into high-tech amateur astronomy, but it certainly will whet their appetites. Mobberley's most valuable advice will save the book's owner many times its cover price: buy a quality telescope from a reputable dealer and install it in a simple shelter so it can be used with as little set-up time as possible. A poor

  7. Enthusiastic Little Astronomers

    Science.gov (United States)

    Novak, Ines

    2016-04-01

    Younger primary school students often show great interest in the vast Universe hiding behind the starry night's sky, but don't have a way of learning about it and exploring it in regular classes. Some of them would search children's books, Internet or encyclopedias for information or facts they are interested in, but there are those whose hunger for knowledge would go unfulfilled. Such students were the real initiators of our extracurricular activity called Little Astronomers. With great enthusiasm they would name everything that interests them about the Universe that we live in and I would provide the information in a fun and interactive yet acceptable way for their level of understanding. In our class we learn about Earth and its place in the Solar System, we learn about the planets and other objects of our Solar System and about the Sun itself. We also explore the night sky using programs such as Stellarium, learning to recognize constellations and name them. Most of our activities are done using a PowerPoint presentation, YouTube videos, and Internet simulations followed by some practical work the students do themselves. Because of the lack of available materials and funds, most of materials are hand made by the teacher leading the class. We also use the school's galileoscope as often as possible. Every year the students are given the opportunity to go to an observatory in a town 90 km away so that they could gaze at the sky through the real telescope for the first time. Our goal is to start stepping into the world of astronomy by exploring the secrets of the Universe and understanding the process of rotation and revolution of our planet and its effects on our everyday lives and also to become more aware of our own role in our part of the Universe. The hunger for knowledge and enthusiasm these students have is contagious. They are becoming more aware of their surroundings and also understanding their place in the Universe that helps them remain humble and helps

  8. Homogeneity study of proton and carbon ion scanning beams using combinations of different spot sizes and grid sizes.

    Science.gov (United States)

    Xing, Ying; Wu, Xianwei; Li, Yongqiang; Zhao, Jun

    2017-09-08

    Different scanning ion beam delivery systems have different delivery accuracies, and the resulting delivery errors will affect field homogeneity. This study was performed to determine an appropriate combination of spot size (FWHM) and spot grid size (GS), which can provide homogenous dose distributions for both proton and carbon ion scanning beam radiotherapy. The combination of the two parameters is represented by a combination factor named n, which is the quotient of FWHM divided by GS. Delivery uncertainties of our beam delivery system were analyzed using log files from the treatment of 28 patients. Square fields for different n values were simulated with and without considering the delivery uncertainties, and the homogeneity of these square fields was analyzed. All spots were located on a rectilinear grid with equal spacing in the x and y directions. In addition to the simulations, we performed experimental measurements using both protons and carbon ions. We selected six energy levels for both proton and carbon ions. For each energy level, we created six square field plans with different n values (1, 1.5, 2, 2.5, 3, 3.5). These plans were delivered and the field homogeneity was determined using a film measurement. The simulations demonstrated that under ideal condition (i.e., the delivery system has no delivery errors), the homogeneity is within 3% when n ≥ 1.1. When delivery uncertainties were included in the simulation, the homogeneity is within 3% when n ≥ 2.3. For film measurements, homogeneity under 3% was achieved when n ≥ 2.5. A practical method to determine the appropriate combination of spot size and grid size is here presented. Considering the uncertainties of the beam delivery system, an n value of 2.5 is good enough to meet the lateral homogeneity requests in our center. The methods used here can be easily repeated in other particle therapy centers. © 2017 American Association of Physicists in Medicine.

  9. The SAGE spectrometer: A tool for combined in-beam γ-ray and conversion electron spectroscopy

    Science.gov (United States)

    Papadakis, P.; Herzberg, R.-D.; Pakarinen, J.; Greenlees, P. T.; Sorri, J.; Butler, P. A.; Coleman-Smith, P. J.; Cox, D.; Cresswell, J. R.; Hauschild, K.; Jones, P.; Julin, R.; Lazarus, I. H.; Letts, S. C.; Parr, E.; Peura, P.; Pucknell, V. F. E.; Rahkila, P.; Sampson, J.; Sandzelius, M.; Seddon, D. A.; Simpson, J.; Thornhill, J.; Wells, D.

    2011-09-01

    The SAGE spectrometer allows simultaneous in-beam γ-ray and internal conversion electron measurements, by combining a germanium detector array with a highly segmented silicon detector and an electron transport system. SAGE is coupled with the ritu gas-filled recoil separator and the great focal-plane spectrometer for recoil-decay tagging studies. Digital electronics are used both for the γ ray and the electron parts of the spectrometer. SAGE was commissioned in the Accelerator Laboratory of the University of Jyväskylä in the beginning of 2010.

  10. High Charge PHIN Photo Injector at CERN with Fast Phase switching within the Bunch Train for Beam Combination

    CERN Document Server

    Csatari Divall, M; Bolzon, B; Bravin, E; Chevallay, E; Dabrowski, A; Doebert, S; Drozdy, A; Fedosseev, V; Hessler, C; Lefevre, T; Livesley, S; Losito, R; Olvegaard, M; Petrarca, M; Rabiller, A N; Egger, D; Mete, O

    2011-01-01

    The high charge PHIN photo-injector was developed within the framework of the European CARE program to provide an alternative to the drive beam thermionic gun in the CTF3 (CLIC Test Facility) at CERN. In PHIN 1908 electron bunches are delivered with bunch spacing of 1.5 GHz and 2.33 nC charge per bunch. Furthermore the drive beam generated by CTF3 requires several fast 180 deg phase-shifts with respect to the 1.5 GHz bunch repetition frequency in order to allow the beam combination scheme developed at CTF3. A total of 8 subtrains, each 140 ns long and shifted in phase with respect to each other, have to be produced with very high phase and amplitude stability. A novel fiber modulator based phase-switching technique developed on the laser system provides this phase-shift between two consecutive pulses much faster and cleaner than the base line scheme, where a thermionic electron gun and sub-harmonic bunching are used. The paper describes the fiber-based switching system and the measurements verifying the schem...

  11. Choosing and using astronomical eyepieces

    CERN Document Server

    Paolini, William

    2013-01-01

    This valuable reference fills a number of needs in the field of astronomical eyepieces, including that of a buyer's guide, observer's field guide and technical desk reference. It documents the past market for eyepieces and its evolution right up to the present day. In addition to appealing to practical astronomers - and potentially saving them money - it is useful both as a historical reference and as a detailed review of the current market place for this bustling astronomical consumer product. What distinguishes this book from other publications on astronomy is the involvement of observers from all aspects of the astronomical community, and also the major manufacturers of equipment. It not only catalogs the technical aspects of the many modern eyepieces but also documents amateur observer reactions and impressions of their utility over the years, using many different eyepieces. Eyepieces are the most talked-about accessories and collectible items available to the amateur astronomer. No other item of equi...

  12. Combined effects of microwaves, electron beams and polyfunctional monomers on rubber vulcanization.

    Science.gov (United States)

    Manaila, Elena; Martin, Diana; Stelescu, Daniela Zuga; Craciun, Gabriela; Ighigeanu, Daniel; Matei, Constantin

    2009-01-01

    This paper presents comparative results obtained by conventional vulcanization with benzoyl peroxide (CV-BP), separate electron beam vulcanization (EB-V) and simultaneous electron beam and microwave vulcanization (EB+MW-V) applied to two kind of rubber samples: EVA (ethylene vinyl acetate) rubber-sample (EVA-sample) and EPDM (ethylene-propylene terpolymer) rubber-sample (EPDM-sample). The EVA-samples contain 61.54% EVA Elvax 260, 30.77% carbon black, 1.85% TAC (triallylcyanurate) polyfunctional monomer and 5.84% filler (zinc oxide, stearic acid, polyethylene glycol and antioxidant). The EPDM-samples contain 61.54% EPDM Nordel 4760, 30.77% carbon black, 1.85% TMPT (trimethylopropane trimethacrylate) polyfunctional monomer and 5.84% filler (zinc oxide, stearic acid, polyethylene glycol and antioxidant). The rubber samples designed for different vulcanization methods were obtained from raw rubber mixtures, as compressed sheets of 2 mm in the polyethylene foils to minimize oxidation. For EB and EB + MW treatments the sheets were cut in rectangular shape 0.15 x 0.15 m2. The physical properties of samples obtained by CV-BP EV-Vand EB + MW-V methods were evaluated by measuring the tearing strength, residual elongation, elongation at break, tensile strength, 300% modulus, 100% modulus, elasticity and hardness. The obtained results demonstrate an improvement of rubber several properties obtained by EB and EB + MW processing as compared to classical procedure using benzoyl peroxide.

  13. Astronomical Image and Data Analysis

    CERN Document Server

    Starck, J.-L

    2006-01-01

    With information and scale as central themes, this comprehensive survey explains how to handle real problems in astronomical data analysis using a modern arsenal of powerful techniques. It treats those innovative methods of image, signal, and data processing that are proving to be both effective and widely relevant. The authors are leaders in this rapidly developing field and draw upon decades of experience. They have been playing leading roles in international projects such as the Virtual Observatory and the Grid. The book addresses not only students and professional astronomers and astrophysicists, but also serious amateur astronomers and specialists in earth observation, medical imaging, and data mining. The coverage includes chapters or appendices on: detection and filtering; image compression; multichannel, multiscale, and catalog data analytical methods; wavelets transforms, Picard iteration, and software tools. This second edition of Starck and Murtagh's highly appreciated reference again deals with to...

  14. Chesley Bonestell's astronomical visions.

    Science.gov (United States)

    Miller, R.

    1994-05-01

    Chesley Bonestell was born before the Wright brothers flew, and he painted cinema backdrops. But fascination with astronomy and friendship with Wernher von Braun led him to paint planetscapes that made spaceflight real to the popular imagination. His unique combination of technical knowledge and graphic prowess brought astronomy alive and helped to advance the manned spaceflight program.

  15. Astronomical Observations by Speckle Interferometry.

    Science.gov (United States)

    1986-06-12

    NUMBER ORGANIZATION O osf appi)81-061 %A mc’S z &I -- St ADRES (ft, Stat. &WCode) 10. SOURCE OF FUNDING NUMBERS C1X1’Z"/A~N ~ ~rf.. PROGRAM IPROJECT...34Masses and Luminosities of the Giant Spectroscopic/Speckle Interferometric Binaries Gamma Persei and Phi Cygni" H.A. McAlister, THE ASTRONOMICAL JOURNAL...Topical Meeting on Information Processing in Astronomy and Optics sponsored by the American Astronomical Society and the Optical Society of America, St

  16. Choosing and using astronomical filters

    CERN Document Server

    Griffiths, Martin

    2014-01-01

    As a casual read through any of the major amateur astronomical magazines will demonstrate, there are filters available for all aspects of optical astronomy. This book provides a ready resource on the use of the following filters, among others, for observational astronomy or for imaging: Light pollution filters Planetary filters Solar filters Neutral density filters for Moon observation Deep-sky filters, for such objects as galaxies, nebulae and more Deep-sky objects can be imaged in much greater detail than was possible many years ago. Amateur astronomers can take

  17. American Brachytherapy Society Task Group Report: Combination of brachytherapy and external beam radiation for high-risk prostate cancer.

    Science.gov (United States)

    Spratt, Daniel E; Soni, Payal D; McLaughlin, Patrick W; Merrick, Gregory S; Stock, Richard G; Blasko, John C; Zelefsky, Michael J

    To review outcomes for high-risk prostate cancer treated with combined modality radiation therapy (CMRT) utilizing external beam radiation therapy (EBRT) with a brachytherapy boost. The available literature for high-risk prostate cancer treated with combined modality radiation therapy was reviewed and summarized. At this time, the literature suggests that the majority of high-risk cancers are curable with multimodal treatment. Several large retrospective studies and three prospective randomized trials comparing CMRT to dose-escalated EBRT have demonstrated superior biochemical control with CMRT. Longer followup of the randomized trials will be required to determine if this will translate to a benefit in metastasis-free survival, disease-specific survival, and overall survival. Although greater toxicity has been associated with CMRT compared to EBRT, recent studies suggest that technological advances that allow better definition and sparing of critical adjacent structures as well as increasing experience with brachytherapy have improved implant quality and the toxicity profile of brachytherapy. The role of androgen deprivation therapy is well established in the external beam literature for high-risk disease, but there is controversy regarding the applicability of these data in the setting of dose escalation. At this time, there is not sufficient evidence for the omission of androgen deprivation therapy with dose escalation in this population. Comparisons with surgery remain limited by differences in patient selection, but the evidence would suggest better disease control with CMRT compared to surgery alone. Due to a series of technological advances, modern combination series have demonstrated unparalleled rates of disease control in the high-risk population. Given the evidence from recent randomized trials, combination therapy may become the standard of care for high-risk cancers. Copyright © 2016 American Brachytherapy Society. Published by Elsevier Inc. All

  18. Silicon-based photonic crystals fabricated using proton beam writing combined with electrochemical etching method.

    Science.gov (United States)

    Dang, Zhiya; Breese, Mark Bh; Recio-Sánchez, Gonzalo; Azimi, Sara; Song, Jiao; Liang, Haidong; Banas, Agnieszka; Torres-Costa, Vicente; Martín-Palma, Raúl José

    2012-07-23

    A method for fabrication of three-dimensional (3D) silicon nanostructures based on selective formation of porous silicon using ion beam irradiation of bulk p-type silicon followed by electrochemical etching is shown. It opens a route towards the fabrication of two-dimensional (2D) and 3D silicon-based photonic crystals with high flexibility and industrial compatibility. In this work, we present the fabrication of 2D photonic lattice and photonic slab structures and propose a process for the fabrication of 3D woodpile photonic crystals based on this approach. Simulated results of photonic band structures for the fabricated 2D photonic crystals show the presence of TE or TM gap in mid-infrared range.

  19. Focus on astronomical predictable events

    DEFF Research Database (Denmark)

    Jacobsen, Aase Roland

    2006-01-01

    At the Steno Museum Planetarium we have for many occasions used a countdown clock to get focus om astronomical events. A countdown clock can provide actuality to predictable events, for example The Venus Transit, Opportunity landing on Mars and The Solar Eclipse. The movement of the clock attracs...

  20. Orbit Modeller - Virtual Astronomical Laboratory

    Science.gov (United States)

    Avdyushev, V. A.; Banshchikova, M. A.; Bordovitsyna, T. V.; Chuvashov, I. N.; Ryabova, G. O.

    2017-09-01

    We present a virtual astronomical laboratory project - "Orbit Modeller" (OM). This should be an interactive web-tool enabling one to simulate numerically the orbital motion of any celestial body within or beyond the solar system. Another function of OM is a repository of old observations and documents.

  1. Astronomical Spectroscopy A Short History

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 5. Astronomical Spectroscopy A Short History. J C Bhattacharyya. General Article Volume 3 Issue 5 May 1998 pp 24-29. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/003/05/0024-0029 ...

  2. High biologically effective dose radiation therapy using brachytherapy in combination with external beam radiotherapy for high-risk prostate cancer

    Directory of Open Access Journals (Sweden)

    Keisei Okamoto

    2017-02-01

    Full Text Available Purpose : To evaluate the outcomes of high-risk prostate cancer patients treated with biologically effective dose (BED ≥ 220 Gy of high-dose radiotherapy, using low-dose-rate (LDR brachytherapy in combination with external beam radiotherapy (EBRT and short-term androgen deprivation therapy (ADT. Material and methods : From 2005 to 2013, a total of 143 patients with high-risk prostate cancer were treated by radiotherapy of BED ≥ 220 Gy with a combination of LDR brachytherapy, EBRT, and androgen deprivation therapy (ADT. The high-risk patients in the present study included both high-risk and very high-risk prostate cancer. The number of high-risk features were: 60 patients with 1 high-risk factor (42%, 61 patients with 2 high-risk factors (43%, and 22 patients with 3 high-risk factors (15% including five N1 disease. External beam radiotherapy fields included prostate and seminal vesicles only or whole pelvis depending on the extension of the disease. Biochemical failure was defined by the Phoenix definition. Results : Six patients developed biochemical failure, thus providing a 5-year actual biochemical failure-free survival (BFFS rate of 95.2%. Biochemical failure was observed exclusively in cases with distant metastasis in the present study. All six patients with biochemical relapse had clinical failure due to bone metastasis, thus yielding a 5-year freedom from clinical failure (FFCF rate of 93.0%. None of the cases with N1 disease experienced biochemical failure. We observed four deaths, including one death from prostate cancer, therefore yielding a cause-specific survival (CSS rate of 97.2%, and an overall survival (OS rate of 95.5%. Conclusions : High-dose (BED ≥ 220 Gy radiotherapy by LDR in combination with EBRT has shown an excellent outcome on BFFS in high-risk and very high-risk cancer, although causal relationship between BED and BFFS remain to be explained further.

  3. Astronomical phenomena in Dresden codex

    Directory of Open Access Journals (Sweden)

    Böhm V.

    2013-01-01

    Full Text Available The relationship between Maya and our calendar is expressed by a coefficient known as ‘correlation’ which is a number of days that we have to add to the Mayan Long Count date to get Julian Date used in astronomy. There is surprisingly large uncertainty in the value of the correlation, yielding a shift between both calendars (and thus between the history of Maya and of our world to typically several hundred years. There are more than 50 diverse values of the correlation, some of them derived from historical, other by astronomical data. We test here (among others the well established Goodman-Martínez-Thompson correlation (GMT, based on historical data, and the Böhms’ one (B&B, based on astronomical data decoded from the Dresden Codex (DC; this correlation differs by about +104 years from the GMT. In our previous works we used several astronomical phenomena as recorded in the DC for a check. We clearly demonstrated that (i the GMT was not capable to predict these phenomena that really happened in nature and (ii that the GMT predicts them on the days when they did not occur. The phenomena used till now in the test are, however, short-periodic and the test then may suffer from ambiguity. Therefore, we add long-periodic astronomical phenomena, decoded successfully from the DC, to the testing. These are (i a synchrony of Venusian heliacal risings with the solar eclipses, (ii a synchrony of Venus and Mars conjunctions with the eclipses, (iii conjunctions of Jupiter and Saturn repeated in a rare way, and (iv a synchrony of synodic and sideric periods of Mercury with the tropical year. Based on our analysis, we find that the B&B correlation yields the best agreement with the astronomical phenomena observed by the Maya. Therefore we recommend to reject the GMT and support the B&B correlation.

  4. Latin American astronomers and the International Astronomical Union

    Science.gov (United States)

    Torres-Peimbert, S.

    2017-07-01

    Selected aspects of the participation of the Latin American astronomers in the International Astronomical Union are presented: Membership, Governing bodies, IAU meetings, and other activities. The Union was founded in 1919 with 7 initial member states, soon to be followed by Brazil. In 1921 Mexico joined, and in 1928 Argentina also formed part of the Union, while Chile joined in 1947. In 1961 Argentina, Brazil, Chile, Mexico and Venezuela were already member countries. At present (October 2016) 72 countries contribute financially to the Union. The Union lists 12,391 professional astronomers as individual members; of those, 692 astronomers work in Latin America and the Caribbean, from 13 member states (Argentina, Bolivia , Brazil, Chile, Colombia, Costa Rica, Cuba, Honduras, Mexico, Panamá, Perú, Uruguay and Venezuela) as well as from Ecuador and Puerto Rico. This group comprises 5.58% of the total membership, a figure somewhat lower than the fraction of the population in the region, which is 8.6% of the world population. Of the Latin American members, 23.4% are women and 76.6% are men; slightly higher than the whole membership of Union, which is of 16.9%. In the governing bodies it can be mentioned that there have been 2 Presidents of the Union (Jorge Sahade and Silvia Torres-Peimbert), 7 VicePresidents (Guillermo Haro, Jorge Sahade, Manuel Peimbert Claudio Anguita, Silvia Torres-Peimbert, Beatriz Barbuy, and Marta G. Rovira). The IAU meetings held in the region, include 2 General Assemblies (the 1991 XXI GA took place in Buenos Aires, Argentina and the 2009 XXVIII GA, in Rio de Janeiro, Brazil), 15 Regional Meetings (in Argentina, Brazil, Chile, Colombia, Mexico, Venezuela and Uruguay), 29 Symposia (in Argentina, Brazil, Chile, Colombia, Costa Rica, Ecuador, Peru and Mexico), 5 Colloquia (in Argentina and Mexico), 8 International Schools for Young Astronomers (in Argentina, Brazil, Cuba, Honduras and Mexico), and 11 projects sponsored by the Office of Astronomy

  5. Combining Acceleration Techniques for Low-Dose X-Ray Cone Beam Computed Tomography Image Reconstruction

    Directory of Open Access Journals (Sweden)

    Hsuan-Ming Huang

    2017-01-01

    Full Text Available Background and Objective. Over the past decade, image quality in low-dose computed tomography has been greatly improved by various compressive sensing- (CS- based reconstruction methods. However, these methods have some disadvantages including high computational cost and slow convergence rate. Many different speed-up techniques for CS-based reconstruction algorithms have been developed. The purpose of this paper is to propose a fast reconstruction framework that combines a CS-based reconstruction algorithm with several speed-up techniques. Methods. First, total difference minimization (TDM was implemented using the soft-threshold filtering (STF. Second, we combined TDM-STF with the ordered subsets transmission (OSTR algorithm for accelerating the convergence. To further speed up the convergence of the proposed method, we applied the power factor and the fast iterative shrinkage thresholding algorithm to OSTR and TDM-STF, respectively. Results. Results obtained from simulation and phantom studies showed that many speed-up techniques could be combined to greatly improve the convergence speed of a CS-based reconstruction algorithm. More importantly, the increased computation time (≤10% was minor as compared to the acceleration provided by the proposed method. Conclusions. In this paper, we have presented a CS-based reconstruction framework that combines several acceleration techniques. Both simulation and phantom studies provide evidence that the proposed method has the potential to satisfy the requirement of fast image reconstruction in practical CT.

  6. Engaging Students through Astronomically Inspired Music

    Science.gov (United States)

    Whitehouse, M.

    2011-09-01

    This paper describes a lesson outline in which astronomically inspired musical compositions are used to teach astronomical concepts via an introductory activity, close listening, and critical/creative reflection.

  7. The astronomical tables of Giovanni Bianchini

    CERN Document Server

    Chabas, Jose

    2009-01-01

    This book describes and analyses, for the first time, the astronomical tables of Giovanni Bianchini of Ferrara (d. after 1469), explains their context, inserts them into an astronomical tradition that began in Toledo, and addresses their diffusion.

  8. Combined external-beam PIXE and /μ-Raman characterisation of garnets used in Merovingian jewellery

    Science.gov (United States)

    Calligaro, T.; Colinart, S.; Poirot, J.-P.; Sudres, C.

    2002-04-01

    Red garnets were the dominant gemstones used for jewels in Europe during the Early Middle Ages. We have studied over 350 garnets set on 12 jewels unearthed in the royal necropolis of the Saint-Denis Basilica, close to Paris. This famous collection of "cloisonné" style artefacts dates from the Merovingian period (late fifth century AD to early seventh century AD). The archaeological issue addressed is the identification of the geographical origin of these garnets, in view to establish the gem trading routes during the Dark Ages. External beam PIXE was used to determine the major constituents (Mg, Al, Si, Ca, Mn, Fe), specifying the garnet type (composition in various mineralogical end-members, e.g. almandine, pyrope, spessartite, …), and the trace element content (Cr, Y). Three sorts of garnets were identified. Ten jewels are adorned with almandine garnets (Fe-rich). One jewel has intermediate almandine-pyrope garnets ("rhodolite"). The last and most recent jewel is inlaid with pyrope (Mg-rich) garnets. Trace element content and slight differences in major composition allowed to distinguish five different sources: two sources for pyrope garnets (with and without chromium), and two sources for almandine garnets (distinctive calcium, magnesium and yttrium contents). A preliminary comparison with literature data suggested that almandine garnets may have been mined from India while the "rhodolite" garnets may have been imported from Sri Lanka. The sources of pyrope garnets could be the Bohemian deposits (Czech republic). In addition, μ-Raman spectrometry was used to identify most of the mineral inclusions (apatite, zircon, ilmenite, monazite, calcite, quartz) present in almandine garnets. Even if two specific types of inclusions were not identified, due to the lack of corresponding reference spectra in our database, the Raman spectra collected provided an interesting inclusion fingerprint.

  9. Combined external-beam PIXE and {mu}-Raman characterisation of garnets used in Merovingian jewellery

    Energy Technology Data Exchange (ETDEWEB)

    Calligaro, T. E-mail: thomas.calligaro@culture.gouv.fr; Colinart, S.; Poirot, J.-P.; Sudres, C

    2002-04-01

    Red garnets were the dominant gemstones used for jewels in Europe during the Early Middle Ages. We have studied over 350 garnets set on 12 jewels unearthed in the royal necropolis of the Saint-Denis Basilica, close to Paris. This famous collection of 'cloisonne' style artefacts dates from the Merovingian period (late fifth century AD to early seventh century AD). The archaeological issue addressed is the identification of the geographical origin of these garnets, in view to establish the gem trading routes during the Dark Ages. External beam PIXE was used to determine the major constituents (Mg, Al, Si, Ca, Mn, Fe), specifying the garnet type (composition in various mineralogical end-members, e.g. almandine, pyrope, spessartite, ...), and the trace element content (Cr, Y). Three sorts of garnets were identified. Ten jewels are adorned with almandine garnets (Fe-rich). One jewel has intermediate almandine-pyrope garnets ('rhodolite'). The last and most recent jewel is inlaid with pyrope (Mg-rich) garnets. Trace element content and slight differences in major composition allowed to distinguish five different sources: two sources for pyrope garnets (with and without chromium), and two sources for almandine garnets (distinctive calcium, magnesium and yttrium contents). A preliminary comparison with literature data suggested that almandine garnets may have been mined from India while the 'rhodolite' garnets may have been imported from Sri Lanka. The sources of pyrope garnets could be the Bohemian deposits (Czech republic). In addition, {mu}-Raman spectrometry was used to identify most of the mineral inclusions (apatite, zircon, ilmenite, monazite, calcite, quartz) present in almandine garnets. Even if two specific types of inclusions were not identified, due to the lack of corresponding reference spectra in our database, the Raman spectra collected provided an interesting inclusion fingerprint.

  10. On the combination of a low energy hydrogen atom beam with a cold multipole ion trap

    Energy Technology Data Exchange (ETDEWEB)

    Borodi, Gheorghe

    2008-12-09

    The first part of the activities of this thesis was to develop a sophisticated ion storage apparatus dedicated to study chemical processes with atomic hydrogen. The integration of a differentially pumped radical beam source into an existing temperature variable 22- pole trapping machine has required major modifications. Since astrophysical questions have been in the center of our interest, the introduction first gives a short overview of astrophysics and -chemistry. The basics of ion trapping in temperature variable rf traps is well-documented in the literature; therefore, the description of the basic instrument (Chapter 2) is kept rather short. Much effort has been put into the development of an intense and stable source for hydrogen atoms the kinetic energy of which can be changed. Chapter 3 describes this module in detail with emphasis on the integration of magnetic hexapoles for guiding the atoms and special treatments of the surfaces for reducing H-H recombination. Due to the unique sensitivity of the rf ion trapping technique, this instrument allows one to study a variety of reactions of astrochemical and fundamental interest. The results of this work are summarized in Chapter 4. Reactions of CO{sub 2}{sup +} with hydrogen atoms and molecules have been established as calibration standard for in situ determination of H and H{sub 2} densities over the full temperature range of the apparatus (10 K-300 K). For the first time, reactions of H- and D-atoms with the ionic hydrocarbons CH{sup +}, CH{sub 2}{sup +}, and CH{sub 4}{sup +} have been studied at temperatures of interstellar space. A very interesting, not yet fully understood collision system is the interaction of protonated methane with H. The outlook presents some ideas, how to improve the new instrument and a few reaction systems are mentioned which may be studied next. (orig.)

  11. A study on port plug distortion caused by narrow gap combined GTAW and SMAW and Electron Beam Welding

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, Pankaj, E-mail: panu012@yahoo.co.in [Department of Ocean Engineering and Naval Architecture, Indian Institute of Technology, Kharagpur, 721302, W.B. (India); Mandal, N.R., E-mail: nrm@naval.iitkgp.ernet.in [Department of Ocean Engineering and Naval Architecture, Indian Institute of Technology, Kharagpur, 721302, W.B. (India); Vasu, Parameswaran, E-mail: parameswaran.vasu@iter-india.org [ITER-India, Institute of Plasma Research, Ahmedabad (India); Padasalag, Shrishail B., E-mail: subhasis.panja@iter-india.org [ITER-India, Institute of Plasma Research, Ahmedabad (India)

    2011-01-15

    A study of port plug distortion resulting from narrow gap combined GTAW and SMAW and Electron Beam Welding was carried out. Thermomechanical finite element analysis of port plug becomes virtually impossible because of the requirement of huge number of nodes and elements. Hence an analysis method based on the concept of inherent strain was used in this work. The computational time required was about 40-50 min only in a Core (TM) 2 Duo, 2.66 GHz computer with 2 GB RAM, which otherwise was not possible with other conventional computation techniques. As was expected the overall distortion due to EB welding was found to be less compared to that of narrow gap GTAW and SMAW.

  12. Combined microfiber knot resonator and focused ion beam-milled Mach-Zehnder interferometer for refractive index measurement

    Science.gov (United States)

    Gomes, André D.; André, Ricardo M.; Warren-Smith, Stephen C.; Dellith, Jan; Becker, Martin; Rothhardt, Manfred; Frazão, Orlando

    2017-04-01

    A Mach-Zehnder interferometer was created from a cavity milled in the taper region next to a microfiber knot resonator. A focused ion beam was used to mill the cavity with 47.8 μm in length. The microfiber knot resonator was created from an 11 μm diameter taper, produced using a filament fusion splicer. After milling the cavity, the microfiber knot resonator spectrum is still visible. The final response of the presented sensor is a microfiber knot resonator spectrum modulated by the Mach-Zehnder interference spectrum. A preliminary result of -8935 ± 108 nm/RIU was obtained for the refractive index sensitivity of the cavity component in a refractive index range of n = 1.333 to 1.341. Simultaneous measurement of refractive index and temperature using this combined structure is a future goal.

  13. Leveraging data lineage to infer logical relationships between astronomical catalogs

    NARCIS (Netherlands)

    Buddelmeijer, Hugo; Valentijn, Edwin A.

    A novel method to infer logical relationships between sets is presented. These sets can be any collection of elements, for example astronomical catalogs of celestial objects. The method does not require the contents of the sets to be known explicitly. It combines incomplete knowledge about the

  14. Astronomical optics and elasticity theory

    CERN Document Server

    Lemaitre, Gerard Rene

    2008-01-01

    Astronomical Optics and Elasticity Theory provides a very thorough and comprehensive account of what is known in this field. After an extensive introduction to optics and elasticity, the book discusses variable curvature and multimode deformable mirrors, as well as, in depth, active optics, its theory and applications. Further, optical design utilizing the Schmidt concept and various types of Schmidt correctors, as well as the elasticity theory of thin plates and shells are elaborated upon. Several active optics methods are developed for obtaining aberration corrected diffraction gratings. Further, a weakly conical shell theory of elasticity is elaborated for the aspherization of grazing incidence telescope mirrors. The very didactic and fairly easy-to-read presentation of the topic will enable PhD students and young researchers to actively participate in challenging astronomical optics and instrumentation projects.

  15. Representations of astronomers in literature.

    Science.gov (United States)

    Haynes, R. D.

    The depiction of astronomers as characters in fiction during the last four centuries provides a useful historical indication of the changing popular perception of astronomy and its practitioners. It is apparent that lay attitudes to astronomy, even in any given period, are complex. On the one hand there is the continuing, innate attraction which the spectacle of the night sky has for people of all ages, the sense of wonder it generates and the preception of astronomy as a "pure" science, free from military and environmentally damaging spin-offs. But, on the other hand, astronomy poses particular and radical challenges to the humanist tradition and these have elicited from many writers not only expressions of anguish and confusion but, at times, a personal attack on the astronomers who were considered responsible for the unwelcome views.

  16. National Astronomical Observatory of Japan

    CERN Document Server

    Haubold, Hans J; UN/ESA/NASA Workshop on the International Heliophysical Year 2007 and Basic Space Science, hosted by the National Astronomical Observatory of Japan

    2010-01-01

    This book represents Volume II of the Proceedings of the UN/ESA/NASA Workshop on the International Heliophysical Year 2007 and Basic Space Science, hosted by the National Astronomical Observatory of Japan, Tokyo, 18 - 22 June, 2007. It covers two programme topics explored in this and past workshops of this nature: (i) non-extensive statistical mechanics as applicable to astrophysics, addressing q-distribution, fractional reaction and diffusion, and the reaction coefficient, as well as the Mittag-Leffler function and (ii) the TRIPOD concept, developed for astronomical telescope facilities. The companion publication, Volume I of the proceedings of this workshop, is a special issue in the journal Earth, Moon, and Planets, Volume 104, Numbers 1-4, April 2009.

  17. The Pisgah Astronomical Research Institute

    Science.gov (United States)

    Cline, J. Donald; Castelaz, M.

    2009-01-01

    Pisgah Astronomical Research Institute is a not-for-profit foundation located at a former NASA tracking station in the Pisgah National Forest in western North Carolina. PARI is celebrating its 10th year. During its ten years, PARI has developed and implemented innovative science education programs. The science education programs are hands-on experimentally based, mixing disciplines in astronomy, computer science, earth and atmospheric science, engineering, and multimedia. The basic tools for the educational programs include a 4.6-m radio telescope accessible via the Internet, a StarLab planetarium, the Astronomical Photographic Data Archive (APDA), a distributed computing online environment to classify stars called SCOPE, and remotely accessible optical telescopes. The PARI 200 acre campus has a 4.6-m, a 12-m and two 26-m radio telescopes, optical solar telescopes, a Polaris monitoring telescope, 0.4-m and 0.35-m optical research telescopes, and earth and atmospheric science instruments. PARI is also the home of APDA, a repository for astronomical photographic plate collections which will eventually be digitized and made available online. PARI has collaborated with visiting scientists who have developed their research with PARI telescopes and lab facilities. Current experiments include: the Dedicated Interferometer for Rapid Variability (Dennison et al. 2007, Astronomical and Astrophysical Transactions, 26, 557); the Plate Boundary Observatory operated by UNAVCO; the Clemson University Fabry-Perot Interferometers (Meriwether 2008, Journal of Geophysical Research, submitted) measuring high velocity winds and temperatures in the Thermosphere, and the Western Carolina University - PARI variable star program. Current status of the education and research programs and instruments will be presented. Also, development plans will be reviewed. Development plans include the greening of PARI with the installation of solar panels to power the optical telescopes, a new distance

  18. Anaximandro : astronomía

    OpenAIRE

    Alonso Bernal, Sonsoles

    2009-01-01

    Anaximander successfully speculated about the origin of the cosmos: an initial explosion which condensated fragments form the stars. He also worked as an empirical astronomer who observed with a helioscope the Sun’s gaseous surface and its protuberances. He observed Solar and Lunar expectrums of light, probably working with certain set of pinhole cameras that he could optimize with fitted mirrors. Anaximandro especuló acertadamente sobre el origen del cosmos: describe una explosión inicial...

  19. Random Numbers from Astronomical Imaging

    OpenAIRE

    Pimbblet, Kevin A.; Bulmer, Michael

    2004-01-01

    This article describes a method to turn astronomical imaging into a random number generator by using the positions of incident cosmic rays and hot pixels to generate bit streams. We subject the resultant bit streams to a battery of standard benchmark statistical tests for randomness and show that these bit streams are statistically the same as a perfect random bit stream. Strategies for improving and building upon this method are outlined.

  20. Astronomical calibration of the Maastrichtian (Late Cretaceous)

    DEFF Research Database (Denmark)

    Husson, Dorothée; Galbrun, Bruno; Laskar, Jacques

    2011-01-01

    Recent improvements to astronomical modeling of the Solar System have contributed to important refinements of the Cenozoic time scale through astronomical calibration of sedimentary series. We extend this astronomical calibration into the Cretaceous, on the base of the 405 ka orbital eccentricity...... of each magnetochron from C32r.2r to C29n are inferred by cycle counting. Astronomical calibrations of Maastrichtian sedimentary series are proposed, based on the 405 ka eccentricity variation according to the most recent astronomical solution La2010a. Two different ages are suggested for the K...

  1. Imaging reconstruction based on improved wavelet denoising combined with parallel-beam filtered back-projection algorithm

    Science.gov (United States)

    Ren, Zhong; Liu, Guodong; Huang, Zhen

    2012-11-01

    The image reconstruction is a key step in medical imaging (MI) and its algorithm's performance determinates the quality and resolution of reconstructed image. Although some algorithms have been used, filter back-projection (FBP) algorithm is still the classical and commonly-used algorithm in clinical MI. In FBP algorithm, filtering of original projection data is a key step in order to overcome artifact of the reconstructed image. Since simple using of classical filters, such as Shepp-Logan (SL), Ram-Lak (RL) filter have some drawbacks and limitations in practice, especially for the projection data polluted by non-stationary random noises. So, an improved wavelet denoising combined with parallel-beam FBP algorithm is used to enhance the quality of reconstructed image in this paper. In the experiments, the reconstructed effects were compared between the improved wavelet denoising and others (directly FBP, mean filter combined FBP and median filter combined FBP method). To determine the optimum reconstruction effect, different algorithms, and different wavelet bases combined with three filters were respectively test. Experimental results show the reconstruction effect of improved FBP algorithm is better than that of others. Comparing the results of different algorithms based on two evaluation standards i.e. mean-square error (MSE), peak-to-peak signal-noise ratio (PSNR), it was found that the reconstructed effects of the improved FBP based on db2 and Hanning filter at decomposition scale 2 was best, its MSE value was less and the PSNR value was higher than others. Therefore, this improved FBP algorithm has potential value in the medical imaging.

  2. Combination of electron beam irradiation and thermal treatment to enhance the shelf-life of traditional Indian fermented food (Idli)

    Science.gov (United States)

    Mulmule, Manoj D.; Shimmy, Shankar M.; Bambole, Vaishali; Jamdar, Sahayog N.; Rawat, K. P.; Sarma, K. S. S.

    2017-02-01

    Idli, a steam-cooked breakfast food item consumed in India, is famous as a staple food for its spongy texture and unique fermented taste. Idli preparation is a time consuming process; although instant Idli pre-mixes as powder or batter are available in the market, they do not have the distinctive taste and aroma similar to the Idli prepared at home. Hence ready-to-eat (RTE) form of this food is in demand. Therefore, an attempt was made to prepare RTE Idli bearing similar taste as home-cooked Idli with an extended shelf-life of up to two months at an ambient temperature using Electron Beam Irradiation (EBI) at dosages 2.5 kGy, 5 kGy and 7.5 kGy and combination processing comprised of EBI dosage at 2.5 kGy and thermal treatment (80 °C for 20 min). The treated Idli's were microbiologically and sensorially evaluated at storage periods of zero day, 14 days, 30 days and 60 days. Idli's irradiated at 7.5 kGy and subjected to combination processing at 2.5 kGy and thermal treatment were shelf-stable for 60 days. 2.5 kGy and 5 kGy radiation dosages alone were not sufficient to preserve Idli samples for more than 14 days. Undesirable change in sensory properties of Idli was observed at an EBI dosage of 7.5 kGy. Sensory properties of combination processed Idli's were found to undergo minor change over the storage period. The present work suggests that lowest radiation dosage in combination with thermal treatment could be useful to achieve the extended shelf-life without considerably impairing the organoleptic quality of Ready-to-Eat Idli.

  3. Parametrial boosting in locally advanced cervical cancer: combined intracavitary/interstitial brachytherapy vs. intracavitary brachytherapy plus external beam radiotherapy.

    Science.gov (United States)

    Mohamed, Sandy; Kallehauge, Jesper; Fokdal, Lars; Lindegaard, Jacob Christian; Tanderup, Kari

    2015-01-01

    Parametrial boost (PB) with external beam radiotherapy (EBRT) aims to increase the dose in the parametrial regions where the contribution from intracavitary brachytherapy (IC BT) is insufficient. An alternative technique for parametrial boosting is combined intracavitary and interstitial (IC-IS) BT. We compared doses delivered by IC BT plus EBRT PB with doses delivered by IC-IS BT. We reviewed 51 consecutive patients with locally advanced cervical cancer with parametrial involvement at diagnosis. At BT, 23 patients had persistent parametrial involvement and were treated with IC-IS BT. For the 23 patients, we simulated a treatment of IC BT combined with EBRT PB and compared it with the delivered IC-IS BT. Equivalent total doses in 2-Gy fractions of the target and organs at risk were evaluated, and the normal tissue volume irradiated to at least 60 Gy (V60). The mean high-risk clinical target volume D90 was comparable (p = 0.8) for both techniques. However, with the EBRT PB scenario, 3 patients received high-risk clinical target volume D90 of 84 Gy for all patients. Organs at risk D(2cm(3)) were significantly higher by a mean of 4-6 Gy (p < 0.001) with EBRT PB. The PB scenario resulted in a significantly higher V60 of 594 ± 596 cm(3) as compared with 228 ± 82 cm(3) with IC-IS BT (p = 0.004). Combined IC-IS BT is superior than IC BT + EBRT PB both in terms of organ sparing and target coverage. The IC-IS BT was more conformal with less normal tissue exposure to intermediate doses (V60). Copyright © 2015 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  4. Californium-252 Brachytherapy Combined With External-Beam Radiotherapy for Cervical Cancer: Long-Term Treatment Results

    Energy Technology Data Exchange (ETDEWEB)

    Lei Xin; Qian Chengyuan; Qing Yi; Zhao Kewei; Yang Zhengzhou; Dai Nan; Zhong Zhaoyang; Tang Cheng; Li Zheng; Gu Xianqing; Zhou Qian; Feng Yan; Xiong Yanli; Shan Jinlu [Cancer Center, Research Institute of Surgery and Daping Hospital, Third Military Medical University, Chongqing (China); Wang Dong, E-mail: dongwang64@hotmail.com [Cancer Center, Research Institute of Surgery and Daping Hospital, Third Military Medical University, Chongqing (China)

    2011-12-01

    Purpose: To observe, by retrospective analysis, the curative effects and complications due to californium-252 ({sup 252}Cf) neutron intracavitary brachytherapy (ICBT) combined with external-beam radiotherapy (EBRT) in the treatment of cervical cancer. Methods and Materials: From February 1999 to December 2007, 696 patients with cervical cancer (Stages IB to IIIB) were treated with {sup 252}Cf-ICBT in combination of EBRT. Of all, 31 patients were at Stage IB, 104 at IIA, 363 at IIB, 64 at IIIA, and 134 at IIIB. Californium-252 ICBT was delivered at 7-12 Gy per insertion per week, with a total dose of 29-45 Gy to reference point A in three to five insertions. The whole pelvic cavity was treated with 8-MV X-ray external irradiation at 2 Gy per fraction, four times per week. After 16-38 Gy of external irradiation, the center of the whole pelvic field was blocked with a 4-cm-wide lead shield, with a total external irradiation dose of 44-56 Gy. The total treatment course was 5 to 6 weeks. Results: Overall survival rate at 3 and 5 years for all patients was 76.0% and 64.9%, respectively. Disease-free 3- and 5-year survival rates of patients were 71.2% and 58.4%, respectively. Late complications included vaginal contracture and adhesion, radiation proctitis, radiation cystitis, and inflammatory bowel, which accounted for 5.8%, 7.1%, 6.2%, and 4.9%, respectively. Univariate analysis results showed significant correlation of stage, age, histopathologic grade, and lymph node status with overall survival. Cox multiple regression analysis showed that the independent variables were stage, histopathologic grade, tumor size, and lymphatic metastasis in all patients. Conclusion: Results of this series suggest that the combined use of {sup 252}Cf-ICBT with EBRT is an effective method for treatment of cervical cancer.

  5. Combined in-beam gamma-ray and conversion electron spectroscopy with radioactive ion beams. Simulations of a silicon detector for the SPEDE spectrometer

    Science.gov (United States)

    Konki, J.; Papadakis, P.; Pakarinen, J.; Butler, P. A.; Davies, P.; Greenlees, P. T.; Herzberg, R. D.; Huyse, M.; Jenkins, D. G.; Julin, R.; O'Neill, G.; Page, R. D.; Rahkila, P.; Ranttila, K.; Thornhill, J.; Van Duppen, P.

    2013-12-01

    In-beam gamma-ray and electron spectroscopy have been widely used as tools to study the broad variety of phenomena in nuclear structure. The SPEDE spectrometer is a new device to be used in conjunction with the MINIBALL germanium detector array to enable the detection of internal conversion electrons in coincidence with gamma rays from de-exciting nuclei in radioactive ion beam experiments at the upcoming HIE-ISOLDE facility at CERN, Switzerland. Geant4 simulations were carried out in order to optimise the design and segmentation of the silicon detector to achieve good energy resolution and performance.

  6. Cultural contacts at International Astronomical Olympiads

    Science.gov (United States)

    Babakhanova, Siranush

    2016-12-01

    It is surprising, but the fact is that the International Olympiads are often only combined with the competition, whereas the intercultural communication between the representatives of different nationalities and the expanding of ideologies of young people are the general-purpose components of not only in frames of the boundaries of scientific expertise, but also such communications, the Olympiads. Worldviews meeting and collaboration are driving forces of progress and play the most important role in the development of the modern science. Armenia participates in the International Astronomical Olympiads since 1997, and in the International Olympiads on Astronomy and Astrophysics since 2013. The Armenian team has always shown high results in competitions and is actively involved in cultural activities.

  7. Comparison of treatment using teletherapy (external beam radiation) alone versus teletherapy combined with brachytherapy for advanced squamous cell carcinoma of the esophagus

    Energy Technology Data Exchange (ETDEWEB)

    Samea, Renato; Lourenco, Laercio Gomes, E-mail: renatosamea@globo.com [Department of Surgical Oncology of Dr. Arnaldo Vieira de Carvalho Hospital, Sao Paulo, SP (Brazil)

    2011-10-15

    Background - Squamous cell carcinoma of the esophagus is still a difficult tumor to treat with very poor prognosis. Aim - To compare the response to teletherapy treatment (external beam radiotherapy) alone versus teletherapy combined with brachytherapy for patients with advanced squamous cell carcinoma of the esophagus. Methods - Were studied 49 patients with advanced squamous cell carcinoma of the esophagus on clinical stage III (TNM-1999). They were separated into two groups. The first, underwent radiation therapy alone with linear accelerator of particles, average dose of 6000 cGy and the second to external beam radiation therapy at a dose of 5040 cGy combined with brachytherapy with Iridium 192 at a dose of 1500 cGy. Brachytherapy started one to two weeks after the end of teletherapy, and it was divided into three weekly applications of 500 cGy. Age, gender, race, habits (smoking and drinking), body mass index (BMI), complications with treatment benefits (pain relief and food satisfaction) and survival were analyzed. Results - The quality of life (food satisfaction, and pain palliation of dysphagia) were better in the group treated with external beam radiation therapy combined with brachytherapy. Survival was higher in the brachytherapy combined with external beam radiation therapy alone. Conclusion - Although the cure rate of squamous cell cancer of the esophagus is almost nil when treated with irradiation alone, this therapy is a form of palliative treatment for most patients in whom surgical contraindication exists. (author)

  8. Astronomical measurement a concise guide

    CERN Document Server

    Lawrence, Andy

    2014-01-01

    This book on astronomical measurement takes a fresh approach to teaching the subject. After discussing some general principles, it follows the chain of measurement through atmosphere, imaging, detection, spectroscopy, timing, and hypothesis testing. The various wavelength regimes are covered in each section, emphasising what is the same, and what is different. The author concentrates on the physics of detection and the principles of measurement, aiming to make this logically coherent. The book is based on a short self contained lecture course for advanced undergraduate students developed and taught by the author over several years.

  9. Explanatory supplement to the astronomical almanac

    CERN Document Server

    Urban, Sean E

    2013-01-01

    The Explanatory Supplement to the Astronomical Almanac offers explanatory material, supplemental information and detailed descriptions of the computational models and algorithms used to produce The Astronomical Almanac, which is an annual publication prepared jointly by the US Naval Observatory and Her Majesty's Nautical Almanac Office in the UK. Like The Astronomical Almanac, The Explanatory Supplement provides detailed coverage of modern positional astronomy. Chapters are devoted to the celestial and terrestrial reference frames, orbital ephemerides, precession, nutation, Earth rotation, and coordinate transformations. These topics have undergone substantial revisions since the last edition was published. Astronomical positions are intertwined with timescales and relativity in The Astronomical Almanac, so related chapters are provided in The Explanatory Supplement. The Astronomical Almanac also includes information on lunar and solar eclipses, physical ephemerides of solar system bodies, and calendars, so T...

  10. Perioperative high-dose-rate interstitial brachytherapy combined with external beam radiation therapy for soft tissue sarcoma.

    Science.gov (United States)

    Sharma, Daya Nand; Deo, S V Suryanarayana; Rath, Goura Kisor; Shukla, Nootan Kumar; Bakhshi, Sameer; Gandhi, Ajeet Kumar; Julka, Pramod Kumar

    2015-01-01

    The aim of our study was to evaluate the role of perioperative high-dose-rate interstitial brachytherapy (PHDRIBT) in combination with external beam radiation therapy (EBRT) in patients with localized soft tissue sarcoma (STS). From year 2004 to 2010, 52 patients with localized STS were treated with wide local excision plus PHDRIBT followed by EBRT. Median size of the tumor was 8 cm (range, 4-19 cm). A single-plane interstitial brachytherapy implant with an average of nine catheters was performed during the surgical resection. The PHDRIBT was started on third postoperative day to deliver a high-dose-rate dose of 16 Gy in four fractions over 2 days using twice-a-day fractionation schedule. After 4 weeks, EBRT was started for a prescription dose of 50 Gy by conventional fractionation. Subsequently, chemotherapy was administered, if indicated as per our institutional policy. Patients were followed up regularly to study local control, survival, and toxicity. At a median followup of 46 months, no patient developed local recurrence, but 12 patients developed distant metastases. The 5-year overall survival and disease-free survival were 67% and 63%, respectively. Main acute toxicity was delayed wound healing observed in 3 patients (5.7%). Commonest late toxicity was chronic skin/subcutaneous fibrosis noticed in 5 patients (9.6%). The PHDRIBT combined with EBRT provides excellent local control and survival rates with acceptable acute and late toxicity in patients with localized STS. Copyright © 2015 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  11. SU-E-J-181: Effect of Prostate Motion On Combined Brachytherapy and External Beam Dose Based On Daily Motion of the Prostate

    Energy Technology Data Exchange (ETDEWEB)

    Narayana, V; McLaughlin, P [Providence Cancer Center, Southfield, MI (United States); University of Michigan, Ann Arbor, MI (United States); Ealbaj, J [University of Michigan, Ann Arbor, MI (United States)

    2015-06-15

    Purpose: In this study, the adequacy of target expansions on the combined external beam and implant dose was examined based on the measured daily motion of the prostate. Methods: Thirty patients received an I–125 prostate implant prescribed to dose of 90Gy. This was followed by external beam to deliver a dose of 90Gyeq (external beam equivalent) to the prostate over 25 to 30 fractions. An ideal IMRT plan was developed by optimizing the external beam dose based on the delivered implant dose. The implant dose was converted to an equivalent external beam dose using the linear quadratic model. Patients were set up on the treatment table by daily orthogonal imaging and aligning the marker seeds in the prostate. Orthogonal images were obtained at the end of treatment to assess prostate intrafraction motion. Based on the observed motion of the markers between the initial and final images, 5 individual plans showing the actual dose delivered to the patient were calculated. A final true dose distribution was established based on summing the implant dose and the 5 external beam plans. Dose to the prostate, seminal vesicles, lymphnodes and normal tissues, rectal wall, urethra and lower sphincter were calculated and compared to ideal. On 18 patients who were sexually active, dose to the corpus cavernosum and internal pudendal artery was also calculated. Results: The average prostate motion in 3 orthogonal directions was less than 1 mm with a standard deviation of less than +2 mm. Dose and volume parameters showed that there was no decrease in dose to the targets and a marginal decrease in dose to in normal tissues. Conclusion: Dose delivered by seed implant moves with the prostate, decreasing the impact of intrafractions dose movement on actual dose delivered. Combined brachytherapy and external beam dose delivered to the prostate was not sensitive to prostate motion.

  12. LGBT Workplace Issues for Astronomers

    Science.gov (United States)

    Kay, Laura E.; Danner, R.; Sellgren, K.; Dixon, V.; GLBTQastro

    2011-01-01

    Federal Equal Employment Opportunity laws and regulations do not provide protection from discrimination on the basis of sexual orientation or gender identity or gender expression. Sexual minority astronomers (including lesbian, gay, bisexual and transgender people; LGBT) can face additional challenges at school and work. Studies show that LGBT students on many campuses report experiences of harassment. Cities, counties, and states may or may not have statutes to protect against such discrimination. There is wide variation in how states and insurance plans handle legal and medical issues for transgender people. Federal law does not acknowledge same-sex partners, including those legally married in the U.S. or in other countries. Immigration rules in the U.S. (and many other, but not all) countries do not recognize same-sex partners for visas, employment, etc. State `defense of marriage act' laws have been used to remove existing domestic partner benefits at some institutions, or benefits can disappear with a change in governor. LGBT astronomers who change schools, institutions, or countries during their career may experience significant differences in their legal, medical, and marital status.

  13. Astronomical Signatures of Dark Matter

    Directory of Open Access Journals (Sweden)

    Paul Gorenstein

    2014-01-01

    Full Text Available Several independent astronomical observations in different wavelength bands reveal the existence of much larger quantities of matter than what we would deduce from assuming a solar mass to light ratio. They are very high velocities of individual galaxies within clusters of galaxies, higher than expected rotation rates of stars in the outer regions of galaxies, 21 cm line studies indicative of increasing mass to light ratios with radius in the halos of spiral galaxies, hot gaseous X-ray emitting halos around many elliptical galaxies, and clusters of galaxies requiring a much larger component of unseen mass for the hot gas to be bound. The level of gravitational attraction needed for the spatial distribution of galaxies to evolve from the small perturbations implied by the very slightly anisotropic cosmic microwave background radiation to its current web-like configuration requires much more mass than is observed across the entire electromagnetic spectrum. Distorted shapes of galaxies and other features created by gravitational lensing in the images of many astronomical objects require an amount of dark matter consistent with other estimates. The unambiguous detection of dark matter and more recently evidence for dark energy has positioned astronomy at the frontier of fundamental physics as it was in the 17th century.

  14. Storing Astronomical Information on the Romanian Territory

    Science.gov (United States)

    Stavinschi, M.; Mioc, V.

    2004-12-01

    Romanian astronomy has a more than 2000-year old tradition, which is, however, little known abroad. The first known archive of astronomical information is the Dacian sanctuary at Sarmizegetusa Regia, erected in the first century AD, having similarities with that of Stonehenge. After a gap of more than 1000 years, more sources of astronomical information become available, mainly records of astronomical events. Monasteries were the safest storage places of these genuine archives. We present a classification of the ways of storing astronomical information, along with characteristic examples.

  15. Astronomical Symbolism in Australian Aboriginal Rock Art

    CERN Document Server

    Norris, Ray P

    2010-01-01

    Traditional Aboriginal Australian cultures include a significant astronomical component, perpetuated through oral tradition and ceremony. This knowledge has practical navigational and calendrical functions, and sometimes extends to a deep understanding of the motion of objects in the sky. Here we explore whether this astronomical tradition is reflected in the rock art of Aboriginal Australians. We find several plausible examples of depictions of astronomical figures and symbols, and also evidence that astronomical observations were used to set out stone arrangements. However, we recognise that the case is not yet strong enough to make an unequivocal statement, and describe our plans for further research.

  16. Instrument Remote Control via the Astronomical Instrument Markup Language

    Science.gov (United States)

    Sall, Ken; Ames, Troy; Warsaw, Craig; Koons, Lisa; Shafer, Richard

    1998-01-01

    The Instrument Remote Control (IRC) project ongoing at NASA's Goddard Space Flight Center's (GSFC) Information Systems Center (ISC) supports NASA's mission by defining an adaptive intranet-based framework that provides robust interactive and distributed control and monitoring of remote instruments. An astronomical IRC architecture that combines the platform-independent processing capabilities of Java with the power of Extensible Markup Language (XML) to express hierarchical data in an equally platform-independent, as well as human readable manner, has been developed. This architecture is implemented using a variety of XML support tools and Application Programming Interfaces (API) written in Java. IRC will enable trusted astronomers from around the world to easily access infrared instruments (e.g., telescopes, cameras, and spectrometers) located in remote, inhospitable environments, such as the South Pole, a high Chilean mountaintop, or an airborne observatory aboard a Boeing 747. Using IRC's frameworks, an astronomer or other scientist can easily define the type of onboard instrument, control the instrument remotely, and return monitoring data all through the intranet. The Astronomical Instrument Markup Language (AIML) is the first implementation of the more general Instrument Markup Language (IML). The key aspects of our approach to instrument description and control applies to many domains, from medical instruments to machine assembly lines. The concepts behind AIML apply equally well to the description and control of instruments in general. IRC enables us to apply our techniques to several instruments, preferably from different observatories.

  17. Validation of the Local Hadronic Calibration Scheme of ATLAS with Combined Beam Test Data in the End-Cap and Forward Regions of ATLAS

    CERN Document Server

    Kiryunin, A; The ATLAS collaboration

    2011-01-01

    The three Atlas calorimeter systems in the region of the forward crack at |eta| = 3.2 in the nominal Atlas setup have been exposed to combined beam tests with single electrons and pions. Detailed shower shape studies of electrons and pions with comparisons to various Geant4 based simulations utilizing different physics lists are presented. The Local Hadron Calibration developed for the energy reconstruction and the calibration of jets and missing transverse energy in ATLAS, has been validated using data obtained during these beam tests. The analysis has been carried out by using special sets of calibration weights and corrections obtained with the Geant4 simulation of a detailed beam test set-up. The validation itself has been performed by careful studying specific calorimeter performance parameters such as e.g. energy response, energy resolution, shower shapes, cluster energy density as well as different physics lists of the Geant4 simulation.

  18. Multidimensional characterisation of biomechanical structures by combining Atomic Force Microscopy and Focused Ion Beam: A study of the rat whisker.

    Science.gov (United States)

    Adineh, Vahid Reza; Liu, Boyin; Rajan, Ramesh; Yan, Wenyi; Fu, Jing

    2015-07-01

    Understanding the heterogeneity of biological structures, particularly at the micro/nano scale can offer insights valuable for multidisciplinary research in tissue engineering and biomimicry designs. Here we propose to combine nanocharacterisation tools, particularly Focused Ion Beam (FIB) and Atomic Force Microscopy (AFM) for three dimensional mapping of mechanical modulus and chemical signatures. The prototype platform is applied to image and investigate the fundamental mechanics of the rat face whiskers, a high-acuity sensor used to gain detailed information about the world. Grazing angle FIB milling was first applied to expose the interior cross section of the rat whisker sample, followed by a "lift-out" method to retrieve and position the target sample for further analyses. AFM force spectroscopy measurements revealed a non-uniform pattern of elastic modulus across the cross section, with a range from 0.8GPa to 13.5GPa. The highest elastic modulus was found at the outer cuticle region of the whisker, and values gradually decreased towards the interior cortex and medulla regions. Elemental mapping with EDS confirmed that the interior of the rat whisker is dominated by C, O, N, S, Cl and K, with a significant change of elemental distribution close to the exterior cuticle region. Based on these data, a novel comprehensive three dimensional (3D) elastic modulus model was constructed, and stress distributions under realistic conditions were investigated with Finite Element Analysis (FEA). The simulations could well account for the passive whisker deflections, with calculated resonant frequency as well as force-deflection for the whiskers being in good agreement with reported experimental data. Limitations and further applications are discussed for the proposed FIB/AFM approach, which holds good promise as a unique platform to gain insights on various heterogeneous biomaterials and biomechanical systems. Copyright © 2015 Acta Materialia Inc. Published by Elsevier

  19. Asteroids astronomical and geological bodies

    CERN Document Server

    Burbine, Thomas H

    2016-01-01

    Asteroid science is a fundamental topic in planetary science and is key to furthering our understanding of planetary formation and the evolution of the Solar System. Ground-based observations and missions have provided a wealth of new data in recent years, and forthcoming missions promise further exciting results. This accessible book presents a comprehensive introduction to asteroid science, summarising the astronomical and geological characteristics of asteroids. The interdisciplinary nature of asteroid science is reflected in the broad range of topics covered, including asteroid and meteorite classification, chemical and physical properties of asteroids, observational techniques, cratering, and the discovery of asteroids and how they are named. Other chapters discuss past, present and future space missions and the threat that these bodies pose for Earth. Based on an upper-level course on asteroids and meteorites taught by the author, this book is ideal for students, researchers and professional scientists ...

  20. Christopher Clavius astronomer and mathematician

    CERN Document Server

    Sigismondi, Costantino

    2012-01-01

    The Jesuit scientist Christopher Clavius (1538-1612) has been the most influential teacher of the renaissance. His contributions to algebra, geometry, astronomy and cartography are enormous. He paved the way, with his texts and his teaching for 40 years in the the Collegio Romano, to the development of these sciences and their fruitful spread all around the World, along the commercial paths of Portugal, which become also the missionary paths for the Jesuits. The books of Clavius were translated into Chinese, by one of his students Matteo Ricci "Li Madou" (1562-1610), and his influence for the development of science in China was crucial. The Jesuits become skilled astronomers, cartographers and mathematicians thanks to the example and the impulse given by Clavius. This success was possible also thanks to the contribution of Clavius in the definition of the Ratio Studiorum, the program of studies, in the Jesuit colleges, so influential for the whole history of modern Europe and all western World.

  1. Ancient Astronomical Monuments of Athens

    Science.gov (United States)

    Theodossiou, E.; Manimanis, V. N.

    2010-07-01

    In this work, four ancient monuments of astronomical significance found in Athens and still kept in the same city in good condition are presented. The first one is the conical sundial on the southern slope of the Acropolis. The second one is the Tower of the Winds and its vertical sundials in the Roman Forum of Athens, a small octagonal marble tower with sundials on all 8 of its sides, plus a water-clock inside the tower. The third monument-instrument is the ancient clepsydra of Athens, one of the findings from the Ancient Agora of Athens, a unique water-clock dated from 400 B.C. Finally, the fourth one is the carved ancient Athenian calendar over the main entrance of the small Byzantine temple of the 8th Century, St. Eleftherios, located to the south of the temple of the Annunciation of Virgin Mary, the modern Cathedral of the city of Athens.

  2. An astronomical observatory for Peru

    Science.gov (United States)

    del Mar, Juan Quintanilla; Sicardy, Bruno; Giraldo, Víctor Ayma; Callo, Víctor Raúl Aguilar

    2011-06-01

    Peru and France are to conclude an agreement to provide Peru with an astronomical observatory equipped with a 60-cm diameter telescope. The principal aims of this project are to establish and develop research and teaching in astronomy. Since 2004, a team of researchers from Paris Observatory has been working with the University of Cusco (UNSAAC) on the educational, technical and financial aspects of implementing this venture. During an international astronomy conference in Cusco in July 2009, the foundation stone of the future Peruvian Observatory was laid at the top of Pachatusan Mountain. UNSAAC, represented by its Rector, together with the town of Oropesa and the Cusco regional authority, undertook to make the sum of 300,000€ available to the project. An agreement between Paris Observatory and UNSAAC now enables Peruvian students to study astronomy through online teaching.

  3. Astronomical Data in Undergraduate courses

    Science.gov (United States)

    Clarkson, William I.; Swift, Carrie; Hughes, Kelli; Burke, Christopher J. F.; Burgess, Colin C.; Elrod, Aunna V.; Howard, Brittany; Stahl, Lucas; Matzke, David; Bord, Donald J.

    2016-06-01

    We present status and plans for our ongoing efforts to develop data analysis and problem-solving skills through Undergraduate Astronomy instruction. While our initiatives were developed with UM-Dearborn’s student body primarily in mind, they should be applicable for a wide range of institution and of student demographics. We focus here on two strands of our effort.Firstly, students in our Introductory Astronomy (ASTR 130) general-education course now perform several “Data Investigations”, in which they interrogate the Hubble Legacy Archive to illustrate important course concepts. This was motivated in part by the realization that typical public data archives now include tools to interrogate the observations that are sufficiently accessible that introductory astronomy students can use them to perform real science, albeit mostly at a descriptive level. We are continuing to refine these investigations, and, most importantly, to critically assess their effectiveness in terms of the student learning outcomes we wish to achieve. This work is supported by grant HST-EO-13758, provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.Secondly, at the advanced-undergraduate level, students taking courses in our Astronomy minor are encouraged to gain early experience in techniques of astronomical observation and analysis that are used by professionals. We present two example projects from the Fall 2015 iteration of our upper-division course ASTR330 (The Cosmic Distance Ladder), one involving Solar System measurements, the second producing calibrated aperture photometry. For both projects students conducted, analysed, and interpreted observations using our 0.4m campus telescope, and used many of the same analysis tools as professional astronomers. This work is supported partly from a Research Initiation and Seed grant from the

  4. Beam instability induced by rf deflectors in the combiner ring of the CLIC test facility and mitigation by damped deflecting structures

    CERN Document Server

    Alesini, D; Biscari, C; Ghigo, A; Corsini, R

    2011-01-01

    In the CTF3 (CLIC test facility 3) run of November 2007, a vertical beam instability has been found in the combiner ring during operation. After a careful analysis, the source of the instability has been identified in the vertical deflecting modes trapped in the rf deflectors and excited by the beam passage. A dedicated tracking code that includes the induced transverse wakefield and the multibunch multipassage effects has been written and the results of the beam dynamics analysis are presented in the paper. The mechanism of the instability was similar to the beam breakup in a linear accelerator or in an energy recovery linac. The results of the code allowed identifying the main key parameters driving such instability and allowed finding the main knobs to mitigate it. To completely suppress such beam instability, two new rf deflectors have been designed, constructed, and installed in the ring. In the new structures the frequency separation between the vertical and horizontal deflecting modes has been increase...

  5. Planetary imaging with amateur astronomical instruments

    Science.gov (United States)

    Papathanasopoulos, k.; Giannaris, G.

    2017-09-01

    Planetary imaging can be varied by the types and size of instruments and processing. With basic amateur telescopes and software, can be captured images of our planetary system, mainly Jupiter, Saturn and Mars, but also solar eclipses, solar flares, and many more. Planetary photos can be useful for professional astronomers, and how amateur astronomers can play a role on that field.

  6. Novel Algorithms for Astronomical Plate Analyses

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... Powerful computers and dedicated software allow effective data mining and scientific analyses in astronomical plate archives. We give and discuss examples of newly developed algorithms for astronomical plate analyses, e.g., searches for optical transients, as well as for major spectral and brightness ...

  7. Astronomers Discover Fastest-Spinning Pulsar

    Science.gov (United States)

    2006-01-01

    Astronomers using the National Science Foundation's Robert C. Byrd Green Bank Telescope have discovered the fastest-spinning neutron star ever found, a 20-mile-diameter superdense pulsar whirling faster than the blades of a kitchen blender. Their work yields important new information about the nature of one of the most exotic forms of matter known in the Universe. Pulsar Graphic Pulsars Are Spinning Neutron Stars CREDIT: Bill Saxton, NRAO/AUI/NSF (Click on image for larger version) "We believe that the matter in neutron stars is denser than an atomic nucleus, but it is unclear by how much. Our observations of such a rapidly rotating star set a hard upper limit on its size, and hence on how dense the star can be.," said Jason Hessels, a graduate student at McGill University in Montreal. Hessels and his colleagues presented their findings to the American Astronomical Society's meeting in Washington, DC. Pulsars are spinning neutron stars that sling "lighthouse beams" of radio waves or light around as they spin. A neutron star is what is left after a massive star explodes at the end of its "normal" life. With no nuclear fuel left to produce energy to offset the stellar remnant's weight, its material is compressed to extreme densities. The pressure squeezes together most of its protons and electrons to form neutrons; hence, the name "neutron star." "Neutron stars are incredible laboratories for learning about the physics of the fundamental particles of nature, and this pulsar has given us an important new limit," explained Scott Ransom, an astronomer at the National Radio Astronomy Observatory and one of Hessels' collaborators on this work. The scientists discovered the pulsar, named PSR J1748-2446ad, in a globular cluster of stars called Terzan 5, located some 28,000 light-years from Earth in the constellation Sagittarius. The newly-discovered pulsar is spinning 716 times per second, or at 716 Hertz (Hz), readily beating the previous record of 642 Hz from a pulsar

  8. Astronomical Polarimetry : new concepts, new instruments, new measurements & observations

    NARCIS (Netherlands)

    Snik, F.

    2009-01-01

    All astronomical sources are polarized to some degree. Polarimetry is therefore a powerful astronomical technique. It furnishes unique diagnostics of e.g. magnetic fields and scattering media. This thesis presents new polarimetric concepts, instruments, and measurements targeting astronomical

  9. A SURVEY OF ASTRONOMICAL RESEARCH: A BASELINE FOR ASTRONOMICAL DEVELOPMENT

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, V. A. R. M. [Astrophysics, Cosmology and Gravity Centre, Department of Astronomy, University of Cape Town, Private Bag X3, Rondebosch 7701 (South Africa); Russo, P. [EU Universe Awareness, Leiden Observatory, Leiden University, PO 9513 Leiden, 2300 RA (Netherlands); Cárdenas-Avendaño, A., E-mail: vribeiro@ast.uct.ac.za, E-mail: russo@strw.leidenuniv.nl [Departamento de Física, Universidad Nacional de Colombia, Carrera 45 No 26-85, Edificio Gutierréz, Bogotá, DC (Colombia)

    2013-12-01

    Measuring scientific development is a difficult task. Different metrics have been put forward to evaluate scientific development; in this paper we explore a metric that uses the number of peer-reviewed, and when available non-peer-reviewed, research articles as an indicator of development in the field of astronomy. We analyzed the available publication record, using the Smithsonian Astrophysical Observatory/NASA Astrophysics Database System, by country affiliation in the time span between 1950 and 2011 for countries with a gross national income of less than 14,365 USD in 2010. This represents 149 countries. We propose that this metric identifies countries in ''astronomical development'' with a culture of research publishing. We also propose that for a country to develop in astronomy, it should invest in outside expert visits, send its staff abroad to study, and establish a culture of scientific publishing. Furthermore, we propose that this paper may be used as a baseline to measure the success of major international projects, such as the International Year of Astronomy 2009.

  10. Astronomers Discover Six-Image Gravitational Lens

    Science.gov (United States)

    2001-08-01

    -Smithsonian Center for Astrophysics (CfA). "When we understand this system, we will have a much clearer picture of how galaxies are changed by being part of a bigger cluster of galaxies," he added. B1359+154 was discovered in 1999 by the Cosmic Lens All-Sky Survey, an international collaboration of astronomers who use radio telescopes to search the sky for gravitational lenses. Images made by the NSF's Very Large Array in New Mexico and by Britain's MERLIN radio telescope showed six objects suspected of being gravitational-lens images, but the results were inconclusive. Rusin and his team used the VLBA and HST in 1999 and 2000 to make more-detailed studies of B1359+154. The combination of data from the VLBA and HST convinced the astronomers that B1359+154 actually consists of six lensed images of a single background galaxy. The VLBA images were made from data collected during observations at a radio frequency of 1.7 GHz. "This is a great example of modern, multi-wavelength astronomy," said Rusin. "We need the radio telescopes to detect the gravitational lenses in the first place, then we need the visible-light information from Hubble to show us additional detail about the structure of the system." Armed with the combined VLBA and HST data about the positions and brightnesses of the six images of the background galaxy as well as the positions of the three intermediate galaxies, the astronomers did computer simulations to show how the gravitation of the three galaxies could produce the lens effect. They were able to design a computer model of the system that, in fact, produces the six images seen in B1359+154. "Our computer model certainly is not perfect, and we need to do more observations of this system to refine it, but we have clearly demonstrated that the three galaxies we see can produce a six-image lens system," said Martin Norbury, a graduate student at Jodrell Bank Observatory in Britain. "We think this work will give us an excellent tool for studying much-denser clusters of

  11. High-Performance Three-Terminal Fin Field-Effect Transistors Fabricated by a Combination of Damage-Free Neutral-Beam Etching and Neutral-Beam Oxidation

    Science.gov (United States)

    Wada, Akira; Sano, Keisuke; Yonemoto, Masahiro; Endo, Kazuhiko; Matsukawa, Takashi; Masahara, Meishoku; Yamasaki, Satoshi; Samukawa, Seiji

    2010-04-01

    Three-terminal fin field-effect transistors (3T-FinFETs) were fabricated by neutral-beam oxidation (NBO) to form gate silicon dioxide (SiO2). The 3T-FinFET fabricated by NBO showed higher device performance - namely, a higher subthreshold slope and a higher effective mobility - than that fabricated by conventional thermal oxidation. It is considered that those improved subthreshold slope and mobility are due to the fact that the three-dimensional structure of a SiO2 film fabricated by NBO has a lower interfacial state density and a lower roughness than a similar structure fabricated by the conventional thermal oxidation of a SiO2 film. The reasons for the lower interfacial state density and lower roughness are the low temperature and lattice plane independence of NBO in comparison with conventional thermal oxidation processes.

  12. Beam-beam instability

    Energy Technology Data Exchange (ETDEWEB)

    Chao, A.W.

    1983-08-01

    The subject of beam-beam instability has been studied since the invention of the colliding beam storage rings. Today, with several colliding beam storage rings in operation, it is not yet fully understood and remains an outstanding problem for the storage ring designers. No doubt that good progress has been made over the years, but what we have at present is still rather primitive. It is perhaps possible to divide the beam-beam subject into two areas: one on luminosity optimization and another on the dynamics of the beam-beam interaction. The former area concerns mostly the design and operational features of a colliding beam storage ring, while the later concentrates on the experimental and theoretical aspects of the beam-beam interaction. Although both areas are of interest, our emphasis is on the second area only. In particular, we are most interested in the various possible mechanisms that cause the beam-beam instability.

  13. beam-beam interaction

    CERN Multimedia

    2017-01-01

    The Beam 1 (represented in blue) and the Beam 2 (represented in red) are colliding with an angle at the Interaction Point (IP). The angle is needed to avoid unwanted multiple collisions along the interaction region. Despite of the separation introduced by the angle, the two beams interact via their electromagnetic field, the so called "beam-beam" interaction.

  14. External Beam Radiation Therapy (EBRT) for Patients with Malignant Pheochromocytoma and Non-Head and Neck Paraganglioma: Combination with 131I-MIBG

    Science.gov (United States)

    Fishbein, Lauren; Bonner, Lara; Torigian, Drew A.; Nathanson, Katherine L.; Cohen, Debbie L.; Pryma, Daniel; Cengel, Keith

    2015-01-01

    In patients with malignant pheochromocytoma and paraganglioma, 131I-MIBG radiotherapy can achieve an objective response rate of 30–50% with the dose limiting toxicity being hematologic. Patients with disseminated disease, who also have a few index bulky or symptomatic lesions, may benefit from the addition of targeted external beam radiotherapy alone or in combination with systemic 131I-MIBG. The records of patients with malignant paraganglioma who were treated with external beam radiotherapy at the University of Pennsylvania from February 1973 to February 2011 were reviewed in an institutional review board approved retrospective study. Of the 17 patients with tumors in the thorax, abdomen, or pelvis, 76% had local control or clinically significant symptomatic relief for at least one year or until death. As expected, the predominant toxicity was due to irradiation of tumor-adjacent normal tissues without clinically significant hematologic toxicity. Due to widespread systemic metastases with areas of bulky, symptomatic tumor, five of the 17 patients were treated with sequential 131I-MIBG (2 mCi/kg per treatment) and external beam radiotherapy to nine sites. In these patients, all areas that were irradiated with external beam radiotherapy showed durable objective response despite all patients eventually experiencing out-of-field systemic progression requiring other treatment. Four of these patients remain alive with excellent performance status 16, 18, 23, and 24 months after external beam radiotherapy. External beam radiotherapy can be highly effective in local management of malignant paraganglioma and can be used in conjunction with 131I-MIBG due to non-overlapping toxicities with excellent control of locally bulky tumors. PMID:22566196

  15. SweepSAR: Beam-forming on Receive Using a Reflector-Phased Array Feed Combination for Spaceborne SAR

    Science.gov (United States)

    Freeman, A.; Krieger, G.; Rosen, P.; Younis, M.; Johnson, W. T. K.; Huber, S.; Jordan, R.; Moreira, A.

    2012-01-01

    In this paper, an alternative approach is described that is suited for longer wavelength SARs in particular, employing a large, deployable reflector antenna and a much simpler phased array feed. To illuminate a wide swath, a substantial fraction of the phased array feed is excited on transmit to sub-illuminate the reflector. Shorter transmit pulses are required than for conventional SAR. On receive, a much smaller portion of the phased array feed is used to collect the return echo, so that a greater portion of the reflector antenna area is used. The locus of the portion of the phased array used on receive is adjusted using an analog beam steering network, to 'sweep' the receive beam(s) across the illuminated swath, tracking the return echo. This is similar in some respects to the whiskbroom approach to optical sensors, hence the name: SweepSAR.SweepSAR has advantages over conventional SAR in that it requires less transmit power, and if the receive beam is narrow enough, it is relatively immune to range ambiguities. Compared to direct radiating arrays with digital beam- forming, it is much simpler to implement, uses currently available technologies, is better suited for longer wavelength systems, and does not require extremely high data rates or onboard processing.

  16. Astronomical background of global huge earthquakes

    Science.gov (United States)

    Hu, Hui; Han, Yan-Ben

    2006-03-01

    This paper analyzes the astronomical background of the global huge earthquakes with M≥8.5. The result shows that most of the earthquakes has occurred in the seismic belts (regions) where is being corresponding seismic active period with the lunar path, solar active falling period and accelerating period of earth rotation. This is as for the variation of long period of astronomical factors. For the variation of short period of astronomical factors, whether for local time or local sidereal time and lunar phase there is the phenomenon of occurrence of concentrating a interval time for the earthquakes. For the short variation of earth rotation this phenomenon is clear; either the earthquakes occur in most fast or in lowest of earth rotation. The above-mentioned results indicate that the eartquakes occurrence is affected by astronomical factors. The astronomical factors are one of motive force causing earthquake from external world. The astronomical factors with long period may act as modulation for the earthquake-pregnant process. And the astronomical factors with short period will causing huge fluctuations of the system and earthquake occur when it act on seismic structure of away from balance state.

  17. Olfactory Neuroblastoma Treated by Endoscopic Surgery Followed by Combined External Beam Radiation and Gamma Knife for Optic Nerve and Chiasm Sparing: A Case Report

    Directory of Open Access Journals (Sweden)

    Hansi Z. Jiang

    2011-01-01

    Full Text Available We describe the multimodality treatment regimen of a 53-year-old man diagnosed with olfactory neuroblastoma (Kadish stage C in the right nasal cavity extending into the ethmoid sinus and across the cribriform plate. Endoscopic surgery for tumor resection was followed by a combination of external beam radiotherapy and stereotactic radiosurgery boost with concurrent chemotherapy. The novel combination of dual radiation therapies allowed for the preservation of the nearby optic structures while providing an adequate dosage to a sufficient volume of the afflicted tissue.

  18. Astronomical Knowledge in Holy Books

    Science.gov (United States)

    Farmanyan, Sona V.; Mickaelian, Areg M.

    2015-08-01

    We investigate religious myths related to astronomy from different cultures in an attempt to identify common subjects and characteristics. The paper focuses on astronomy in religion. The initial review covers records from Holy books about sky related superstitious beliefs and cosmological understanding. The purpose of this study is to introduce sky related religious and national traditions (particularly based on different calendars; Solar or Lunar). We carried out a comparative study of astronomical issues contained in a number of Holy books: Ancient Egyptian Religion (Pyramid Texts), Zoroastrianism (Avesta), Hinduism (Vedas), Buddhism (Tipitaka), Confucianism (Five Classics), Sikhism (Guru Granth Sahib), Christianity (Bible), Islam (Quran), Druidism (Mabinogion) and Maya Religion (Popol Vuh). These books include various information on the creation of the Universe, Sun and Moon, the age of the Universe, Cosmic sizes, understanding about the planets, stars, Milky Way and description of the Heavens in different religions. We come to the conclusion that the perception of celestial objects varies from culture to culture, and from religion to religion and preastronomical views had a significant impact on humankind, particularly on religious diversities. We prove that Astronomy is the basis of cultures, and that national identity and mythology and religion were formed due to the special understanding of celestial objects.

  19. Lunar astronomical observatories - Design studies

    Science.gov (United States)

    Johnson, Stewart W.; Burns, Jack O.; Chua, Koon Meng; Duric, Nebojsa; Gerstle, Walter H.

    1990-01-01

    The best location in the inner solar system for the grand observatories of the 21st century may be the moon. A multidisciplinary team including university students and faculty in engineering, astronomy, physics, and geology, and engineers from industry is investigating the moon as a site for astronomical observatories and is doing conceptual and preliminary designs for these future observatories. Studies encompass lunar facilities for radio astronomy and astronomy at optical, ultraviolet, and infrared wavelengths of the electromagnetic spectrum. Although there are significant engineering challenges in design and construction on the moon, the rewards for astronomy can be great, such as detection and study of earth-like planets orbiting nearby stars, and the task for engineers promises to stimulate advances in analysis and design, materials and structures, automation and robotics, foundations, and controls. Fabricating structures in the reduced-gravity environment of the moon will be easier than in the zero-gravity environment of earth orbit, as Apollo and space-shuttle missions have revealed. Construction of observatories on the moon can be adapted from techniques developed on the earth, with the advantage that the moon's weaker gravitational pull makes it possible to build larger devices than are practical on earth.

  20. Astronomical problems an introductory course in astronomy

    CERN Document Server

    Vorontsov-Vel'Yaminov, B A

    1969-01-01

    Astronomical Problems: An Introductory Course in Astronomy covers astronomical problems, together with a summary of the theory and the formula to be exercised. The book discusses the types of problems solved with the help of the celestial globe and how to solve astronomical problems. The text tackles problems on interpolation, the celestial sphere, systems of celestial coordinates, and culmination. Problems about the rising and setting of a heavenly body, precession, planetary movement, and parallax and aberration are also considered. The book presents problems about refraction, the apparent m

  1. Knowledge Discovery Workflows in the Exploration of Complex Astronomical Datasets

    Science.gov (United States)

    D'Abrusco, Raffaele; Fabbiano, Giuseppina; Laurino, Omar; Massaro, Francesco

    2015-03-01

    The massive amount of data produced by the recent multi-wavelength large-area surveys has spurred the growth of unprecedentedly massive and complex astronomical datasets that are proving the traditional data analysis techniques more and more inadequate. Knowledge discovery techniques, while relatively new to astronomy, have been successfully applied in several other quantitative disciplines for the determination of patterns in extremely complex datasets. The concerted use of different unsupervised and supervised machine learning techniques, in particular, can be a powerful approach to answer specific questions involving high-dimensional datasets and degenerate observables. In this paper I will present CLaSPS, a data-driven methodology for the discovery of patterns in high-dimensional astronomical datasets based on the combination of clustering techniques and pattern recognition algorithms. I shall also describe the result of the application of CLaSPS to a sample of a peculiar class of AGNs, the blazars.

  2. Astronomical optical interferometry, I: Methods and instrumentation

    Directory of Open Access Journals (Sweden)

    Jankov S.

    2010-01-01

    Full Text Available Previous decade has seen an achievement of large interferometric projects including 8-10m telescopes and 100m class baselines. Modern computer and control technology has enabled the interferometric combination of light from separate telescopes also in the visible and infrared regimes. Imaging with milli-arcsecond (mas resolution and astrometry with micro-arcsecond (µas precision have thus become reality. Here, I review the methods and instrumentation corresponding to the current state in the field of astronomical optical interferometry. First, this review summarizes the development from the pioneering works of Fizeau and Michelson. Next, the fundamental observables are described, followed by the discussion of the basic design principles of modern interferometers. The basic interferometric techniques such as speckle and aperture masking interferometry, aperture synthesis and nulling interferometry are discussed as well. Using the experience of past and existing facilities to illustrate important points, I consider particularly the new generation of large interferometers that has been recently commissioned (most notably, the CHARA, Keck, VLT and LBT Interferometers. Finally, I discuss the longer-term future of optical interferometry, including the possibilities of new large-scale ground-based projects and prospects for space interferometry.

  3. Longwave Imaging for Astronomical Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a compact portable longwave camera for astronomical applications. In Phase 1, we will develop and deliver the focal plane array (FPA) - a...

  4. Longwave Imaging for Astronomical Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a compact portable longwave camera for astronomical applications. In Phase 1, we successfully developed the eye of the camera, i.e. the focal...

  5. Astronomers no longer in the dark

    CERN Multimedia

    MacMillan, L

    2002-01-01

    In a significant breakthrough, British and US astronomers have begun to pin down the most elusive material in the universe. They have made a map of dark matter - the heavy, invisible stuff that gives the galaxies their shape (1 page).

  6. Astronomers find distant planet like Jupiter

    CERN Multimedia

    2003-01-01

    Astronomers searching for planetary systems like our solar system have found a planet similar to Jupiter orbiting a nearby star similar to our Sun, about 90 light-years from Earth, according to researchers (1/2 page).

  7. Astronomers Unveiling Life's Cosmic Origins

    Science.gov (United States)

    2009-02-01

    Processes that laid the foundation for life on Earth -- star and planet formation and the production of complex organic molecules in interstellar space -- are yielding their secrets to astronomers armed with powerful new research tools, and even better tools soon will be available. Astronomers described three important developments at a symposium on the "Cosmic Cradle of Life" at the annual meeting of the American Association for the Advancement of Science in Chicago, IL. Chemistry Cycle The Cosmic Chemistry Cycle CREDIT: Bill Saxton, NRAO/AUI/NSF Full Size Image Files Chemical Cycle Graphic (above image, JPEG, 129K) Graphic With Text Blocks (JPEG, 165K) High-Res TIFF (44.2M) High-Res TIFF With Text Blocks (44.2M) In one development, a team of astrochemists released a major new resource for seeking complex interstellar molecules that are the precursors to life. The chemical data released by Anthony Remijan of the National Radio Astronomy Observatory (NRAO) and his university colleagues is part of the Prebiotic Interstellar Molecule Survey, or PRIMOS, a project studying a star-forming region near the center of our Milky Way Galaxy. PRIMOS is an effort of the National Science Foundation's Center for Chemistry of the Universe, started at the University of Virginia (UVa) in October 2008, and led by UVa Professor Brooks H. Pate. The data, produced by the NSF's Robert C. Byrd Green Bank Telescope (GBT) in West Virginia, came from more than 45 individual observations totalling more than nine GigaBytes of data and over 1.4 million individual frequency channels. Scientists can search the GBT data for specific radio frequencies, called spectral lines -- telltale "fingerprints" -- naturally emitted by molecules in interstellar space. "We've identified more than 720 spectral lines in this collection, and about 240 of those are from unknown molecules," Remijan said. He added, "We're making available to all scientists the best collection of data below 50 GHz ever produced for

  8. Astronomical technology - the past and the future

    OpenAIRE

    Appenzeller, Immo

    2017-01-01

    The past fifty years have been an epoch of impressive progress in the field of astronomical technology. Practically all the technical tools, which we use today, have been developed during that time span. While the first half of this period has been dominated by advances in the detector technologies, during the past two decades innovative telescope concepts have been developed for practically all wavelength ranges where astronomical observations are possible. Further important advances can be ...

  9. Recent Development in Astronomic Position Determinations.

    Science.gov (United States)

    1984-10-25

    community. The comparison of astronomic position determinations using the DanJon and the VUGTK astrolabes published by the German Geodetic Commission...these tests indicated that astrolabes were capable of precision and accuracy surpassing those obtainable with astronomic theodolites, even though some...the urgent need to replace the base instrument with a precise astrolable designed for.maximum optical efficiency with the CID eyepiece. An astrolabe

  10. Basic Optics for the Astronomical Sciences

    CERN Document Server

    Breckinridge, James

    2012-01-01

    This text was written to provide students of astronomy and engineers an understanding of optical science - the study of the generation, propagation, control, and measurement of optical radiation - as it applies to telescopes and instruments for astronomical research in the areas of astrophysics, astrometry, exoplanet characterization, and planetary science. The book provides an overview of the elements of optical design and physical optics within the framework of the needs of the astronomical community.

  11. Combined photon-electron beams in the treatment of the supraclavicular lymph nodes in breast cancer: A novel technique that achieves adequate coverage while reducing lung dose.

    Science.gov (United States)

    Salem, Ahmed; Mohamad, Issa; Dayyat, Abdulmajeed; Kanaa'n, Haitham; Sarhan, Nasim; Roujob, Ibrahim; Salem, Abdel-Fattah; Afifi, Shatha; Jaradat, Imad; Mubiden, Rasmi; Almousa, Abdelateif

    2015-01-01

    Radiation pneumonitis is a well-documented side effect of radiation therapy for breast cancer. The purpose of this study was to compare combined photon-electron, photon-only, and electron-only plans in the radiation treatment of the supraclavicular lymph nodes. In total, 13 patients requiring chest wall and supraclavicular nodal irradiation were planned retrospectively using combined photon-electron, photon-only, and electron-only supraclavicular beams. A dose of 50Gy over 25 fractions was prescribed. Chest wall irradiation parameters were fixed for all plans. The goal of this planning effort was to cover 95% of the supraclavicular clinical target volume (CTV) with 95% of the prescribed dose and to minimize the volume receiving ≥ 105% of the dose. Comparative end points were supraclavicular CTV coverage (volume covered by the 95% isodose line), hotspot volume, maximum radiation dose, contralateral breast dose, mean total lung dose, total lung volume percentage receiving at least 20 Gy (V(20 Gy)), heart volume percentage receiving at least 25 Gy (V(25 Gy)). Electron and photon energies ranged from 8 to 18 MeV and 4 to 6 MV, respectively. The ratio of photon-to-electron fractions in combined beams ranged from 5:20 to 15:10. Supraclavicular nodal coverage was highest in photon-only (mean = 96.2 ± 3.5%) followed closely by combined photon-electron (mean = 94.2 ± 2.5%) and lowest in electron-only plans (mean = 81.7 ± 14.8%, p photon-electron (mean = 50.8 ± 40.9 cm(3)) and photon-only beams (mean = 32.2 ± 28.1 cm(3), p = 0.114). Heart V(25 Gy) was not statistically different among the plans (p = 0.999). Total lung V(20 Gy) was lowest in electron-only (mean = 10.9 ± 2.3%) followed by combined photon-electron (mean = 13.8 ± 2.3%) and highest in photon-only plans (mean = 16.2 ± 3%, p photon-only plans demonstrated the highest target coverage and total lung V(20 Gy). The superiority of electron-only beams, in terms of decreasing lung dose, is set back by the

  12. Free vibration analysis of straight-line beam regarded as distributed system by combining Wittrick-Williams algorithm and transfer dynamic stiffness coefficient method

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Myung Soo; Yang, Kyong Uk [Chonnam National University, Yeosu (Korea, Republic of); Kondou, Takahiro [Kyushu University, Fukuoka (Japan); Bonkobara, Yasuhiro [University of Miyazaki, Miyazaki (Japan)

    2016-03-15

    We developed a method for analyzing the free vibration of a structure regarded as a distributed system, by combining the Wittrick-Williams algorithm and the transfer dynamic stiffness coefficient method. A computational algorithm was formulated for analyzing the free vibration of a straight-line beam regarded as a distributed system, to explain the concept of the developed method. To verify the effectiveness of the developed method, the natural frequencies of straight-line beams were computed using the finite element method, transfer matrix method, transfer dynamic stiffness coefficient method, the exact solution, and the developed method. By comparing the computational results of the developed method with those of the other methods, we confirmed that the developed method exhibited superior performance over the other methods in terms of computational accuracy, cost and user convenience.

  13. Determination of the D/T fuel mixture using two-photon laser induced fluorescence in combination with neutral beam injection

    Energy Technology Data Exchange (ETDEWEB)

    Voslamber, D.; Mandl, W

    1997-08-01

    Doppler-free two-photon induced fluorescence in the Lyman-{alpha} lines of H, D and T has been suggested previously as a local and isotope-selective diagnostic of the intrinsic neutral hydrogen densities in magnetically confined fusion plasmas. In the present paper it is shown that the diagnostic potential of this method is significantly increased if it is combined with neutral atom beams whose characteristics are such that efficient production of thermal ground state atoms via charge exchange reactions is achieved. Considerably deeper plasma regions than just the plasma edge can thus be probed and local, isotope-selective information is obtained on the more relevant ions rather than on the neutrals. Additional diagnostic possibilities, e.g. those arising from the spectroscopic investigation of the beam particles themselves, are also discussed. (author) 21 refs.

  14. A Real-Time FPGA based Algorithm for the combination of Beam Loss Acquisition Methods used for Measurement Dynamic Range expansion

    CERN Document Server

    Kwiatkowski, M; Alsdorf, M; Dehning, B; Vigano, W

    2012-01-01

    The aim of the Beam Loss Monitoring Dual Polarity (BLEDP) module under development at the European Organisation for Nuclear Research (CERN) is to measure and digitise with high precision the current produced by several types of beam loss detectors. The BLEDP module consists of eight analogue channels each with a fully differential integrator and an accompanying 16 bit ADC at the output of each analogue integrator. The on-board FPGA device controls the integral periods, instructs the ADC devices to perform measurements at the end of each period and collects the measurements. In the next stage it combines the number of charge and discharge cycles accounted in the last interval together with the cycle fractions observed using the ADC samples to produce a digitised high precision value of the charges collected. This paper describes briefly the principle of the fully differential integrator and focuses on the algorithm employed to process the digital data.

  15. A Refined Astronomically Calibrated 40Ar/39Ar Age for Fish Canyon Sanidine

    DEFF Research Database (Denmark)

    Rivera, Tiffany; Storey, Michael; Zeeden, Christian

    2011-01-01

    Intercalibration between the astronomical and radio-isotopic dating methods provides a means to improving accuracy and reducing uncertainty of an integrated, multi-chronometer geologic timescale. Here we report a high-precision 40Ar/39Ar age for the Fish Canyon sanidine (FCs) neutron fluence...... monitor, by multi-collector noble gas mass spectrometry, through cross-calibration with A1 tephra sanidines (A1Ts) of the direct astronomically tuned Faneromeni section (Crete). The astronomically intercalibrated 40Ar/39Ar age of FCs of 28.172±0.028 Ma (2σ, external errors) is within the uncertainty of......, but more precise (±0.10%) than, the previous 40Ar/39Ar age determined by intercalibration with astronomically tuned tephras from the Melilla Basin (Morocco). Using this proposed age for FCs, combined with measurements using the A1Ts as the neutron fluence monitor, a weighted mean Bishop Tuff 40Ar/39Ar...

  16. Small field depth dose profile of 6 MV photon beam in a simple air-water heterogeneity combination: A comparison between anisotropic analytical algorithm dose estimation with thermoluminescent dosimeter dose measurement

    Directory of Open Access Journals (Sweden)

    Abhijit Mandal

    2017-01-01

    Conclusion: The trend of estimation error of AAA dose calculation algorithm with respect to measured value have been formulated throughout the radiation path length along the central axis of 6 MV photon beam in air-water heterogeneity combination for small field size photon beam generated from a 6 MV linear accelerator.

  17. Multi-arm spectrometer for parallel frequency analysis of radio-wave signals oriented to astronomical observations

    Science.gov (United States)

    Shcherbakov, Alexandre S.; Chavez Dagostino, Miguel; Arellanes, Adan Omar; Tepichin Rodriguez, Eduardo

    2017-08-01

    We describe a potential prototype of modern spectrometer based on acousto-optical technique with three parallel optical arms for analysis of radio-wave signals specific to astronomical observations. Each optical arm exhibits original performances to provide parallel multi-band observations with different scales simultaneously. Similar multi-band instrument is able to realize measurements within various scenarios from planetary atmospheres to attractive objects in the distant Universe. The arrangement under development has two novelties. First, each optical arm represents an individual spectrum analyzer with its individual performances. Such an approach is conditioned by exploiting various materials for acousto-optical cells operating within various regimes, frequency ranges, and light wavelengths from independent light sources. Individually produced beam shapers give both the needed incident light polarization and the required apodization for light beam to increase the dynamic range of the system as a whole. After parallel acousto-optical processing, a few data flows from these optical arms are united by the joint CCD matrix on the stage of the combined extremely high-bit rate electronic data processing that provides the system performances as well. The other novelty consists in the usage of various materials for designing wide-aperture acousto-optical cells exhibiting the best performances within each of optical arms. Here, one can mention specifically selected cuts of tellurium dioxide, bastron, and lithium niobate, which overlap selected areas within the frequency range from 40 MHz to 2.0 GHz. Thus one yields the united versatile instrument for comprehensive studies of astronomical objects simultaneously with precise synchronization in various frequency ranges.

  18. Astronomers Get New Tools for Gravitational-Wave Detection

    Science.gov (United States)

    2010-01-01

    exclaimed. "Fermi showed us where to look." "This is a huge help in our effort to use millisecond pulsars to detect gravitational waves," Ransom said. The more such pulsars scientists can find and observe over time, the more likely they are to detect gravitational waves, he explained. He said that astronomers now have barely enough millisecond pulsars to make a convincing gravitational-wave detection. "With Fermi guiding the way, though, we can change that picture quickly," Ray said. "We've just started to follow up on the objects located by Fermi, and have many more to go, with a great success rate so far," he added. Ransom, along with his colleague Mallory Roberts of Eureka Scientific, used the National Science Foundation's Robert C. Byrd Green Bank Telescope (GBT) to find eight of the 17 new pulsars. The scientists announced their discoveries at the American Astronomical Society's meeting in Washington, DC. Pulsars are neutron stars -- the dense cores left after a massive star has exploded as a supernova. About as large as a medium-sized city, these neutron stars have strong magnetic fields that channel lighthouse-like beams of radio waves that sweep through space as the star rotates. When such a beam strikes the Earth, radio telescopes can detect the strong radio waves. As they age, pulsars slow their rotation rates. However, if the pulsar is part of a binary-star system and can draw in material from its companion, its rotation can be sped up. When the neutron star has been sped up to rotate hundreds of times a second, it is called a millisecond pulsar. In addition to helping scientists detect gravitational waves, study of millisecond pulars also can yield important new information about other effects of General Relativity and about fundamental particle physics. "This new ability to find many more millisecond pulsars really is a treasure chest that can yield many valuable gems of scientific discovery," Ransom said.

  19. Numerical simulations on conformable laser-induced interstitial thermotherapy through combined use of multi-beam heating and biodegradable nanoparticles.

    Science.gov (United States)

    Zhang, Jie; Jin, Chao; He, Zhi-Zhu; Liu, Jing

    2014-07-01

    Clinically, precisely heating and thus completely ablating diseased tumor tissue through laser beam is still facing many technical challenges. In this study, numerical simulation of a conformal heating modality based on multi-beam laser along with biodegradable magnesium nanoparticles (Mg-NPs) was put forward to treat liver tumor with large size or irregular shape. Further, a Gaussian-like distribution was proposed to investigate the influence of Mg-NP deposition on the nanoenhanced laser-induced interstitial thermotherapy (LITT). A temperature feedback system was adopted to control the temperature range to avoid overheating. To preliminarily validate the heating enhancement induced by the applied multi-beam laser and Mg-NPs, a conceptual experiment was performed. Both theoretical simulation and experimental measurements demonstrated that multi-beam laser with Mg-NPs could improve efficiency in the conformal heating of tumors with irregular shape or large size. In addition, the distribution and content of Mg-NPs produced significant impact on thermotherapy: (1) The adjustable parameter σ in the Gaussian-like distribution could reflect various practical situations and diffusivities of Mg-NPs; (2) under the premise of the same concentration of Mg-NPs and short time to heat a small-sized target, the whole liver tumor containing Mg-NPs could not improve the efficiency as the nanoparticles limited the photons to be absorbed only around the fibers, while liver tumor partially containing Mg-NPs could improve the thermotherapy efficiency up to 20 %; and (3) the addition of Mg-NPs was rather beneficial for realizing a conformal heating as the residual thermal energy was much less than that without Mg-NPs. This study suggests a feasible and promising modality for planning a high-performance LITT in future clinics.

  20. The combination of digital surface scanners and cone beam computed tomography technology for guided implant surgery using 3Shape implant studio software: a case history report.

    Science.gov (United States)

    Lanis, Alejandro; Álvarez Del Canto, Orlando

    2015-01-01

    The incorporation of virtual engineering into dentistry and the digitization of information are providing new perspectives and innovative alternatives for dental treatment modalities. The use of digital surface scanners with surgical planning software allows for the combination of the radiographic, prosthetic, surgical, and laboratory fields under a common virtual scenario, permitting complete digital treatment planning. In this article, the authors present a clinical case in which a guided implant surgery was performed based on a complete digital surgical plan combining the information from a cone beam computed tomography scan and the virtual simulation obtained from the 3Shape TRIOS intraoral surface scanner. The information was imported to and combined in the 3Shape Implant Studio software for guided implant surgery planning. A surgical guide was obtained by a 3D printer, and the surgical procedure was done using the Biohorizons Guided Surgery Kit and its protocol.

  1. Advances in Exoplanet Observing by Amateur Astronomers (Abstract)

    Science.gov (United States)

    Conti, D. M.

    2017-06-01

    (Abstract only) This past year has seen a marked increase in amateur astronomer participation in exoplanet research. This has ranged from amateur astronomers helping professional astronomers confirm candidate exoplanets, to helping refine the ephemeris of known exoplanets. In addition, amateur astronomers have been involved in characterizing such exotic objects as disintegrating planetesimals. However, the involvement in such pro/am collaborations has also required that amateur astronomers follow a more disciplined approach to exoplanet observing.

  2. A Kalman filter approach to realize the lowest astronomical tide surface

    NARCIS (Netherlands)

    Slobbe, D.C.; Sumihar, JH; Frederikse, T.; Verlaan, M.; Klees, R.; Zijl, F; Hashemi Farahani, H.; Broekman, R

    2017-01-01

    In this paper, we present a novel Kalman filter approach to combine a hydrodynamic model-derived lowest astronomical tide (LAT) surface with tide gauge record-derived LAT values. In the approach, tidal water levels are assimilated into the model. As such, the combination is guided by the model

  3. Beam-surface scattering studies of the individual and combined effects of VUV radiation and hyperthermal O, O2, or Ar on FEP Teflon surfaces.

    Science.gov (United States)

    Brunsvold, Amy L; Zhang, Jianming; Upadhyaya, Hari P; Minton, Timothy K

    2009-01-01

    Beam-surface scattering experiments were used to probe products that scattered from FEP Teflon surfaces during bombardment by various combinations of atomic and molecular oxygen, Ar atoms, and vacuum ultraviolet (VUV) light. A laser-breakdown source was used to create hyperthermal (translational energies in the range 4-13 eV) beams of argon and atomic/molecular oxygen. The average incidence energy of these beams was tunable and was controlled precisely with a synchronized chopper wheel. A filtered deuterium lamp provided a source of VUV light in a narrow-wavelength range centered at 161 nm. Volatile products that exited the surfaces were monitored with a rotatable mass spectrometer detector. Hyperthermal O atoms with average translational energies above approximately 4 eV may react directly with a pristine FEP Teflon surface, and the reactivity appears to increase with the translational energy of the incident O atoms. VUV light or highly energetic collisions of O2 or Ar may break chemical bonds and lead to the ejection of volatile products; the ejection of volatile products is enhanced when the surface is subjected to VUV light and energetic collisions simultaneously. Exposure to VUV light or to hyperthermal O2 or Ar may increase the reactivity of an FEP Teflon surface to O atoms.

  4. Test facility for astronomical x-ray optics

    DEFF Research Database (Denmark)

    Christensen, Finn Erland; Lewis, Robert A.; Bordas, J.

    1990-01-01

    Grazing incidence x-ray optics for x-ray astronomical applications are used outside the earth's atmosphere. These devices require a large collection aperture and the imaging of an x-ray source that is essentially placed at infinity. The ideal testing system for these optical elements has...... to approximate that encountered under working conditions; however, the testing of these optical elements is notoriously difficult with conventional x-ray generators. Synchrotron radiation (SR) sources are sufficiently brilliant to produce a nearly perfect parallel beam over a large area while still retaining...... a flux considerably higher than that available from conventional x-ray generators. A facility designed for the testing of x-ray optics, particularly in connection with x-ray telescopes, is described. It is proposed that this facility will be accommodated at the Synchrotron Radiation Source...

  5. A Test Facility For Astronomical X-Ray Optics

    DEFF Research Database (Denmark)

    Lewis, R. A.; Bordas, J.; Christensen, Finn Erland

    1989-01-01

    Grazing incidence x-ray optics for x-ray astronomical applications are used outside the earths atmosphere. These devices require a large collection aperture and the imaging of an x-ray source which is essentially placed at infinity. The ideal testing system for these optical elements has...... to approximate that encountered under working conditions, however the testing of these optical elements is notoriously difficult with conventional x-ray generators. Synchrotron Radiation (SR) sources are sufficiently brilliant to produce a nearly perfect parallel beam over a large area whilst still retaining...... a flux considerably higher than that available from conventional x-ray generators. A facility designed for the testing of x-ray optics, particularly in connection with x-ray telescopes is described below. It is proposed that this facility will be accommodated at the Synchrotron Radiation Source...

  6. SU-G-JeP1-01: A Combination of Real Time Electromagnetic Localization and Tracking with Cone Beam Computed Tomography in Stereotactic Radiosurgery for Brain Tumors

    Energy Technology Data Exchange (ETDEWEB)

    Muralidhar, K Raja; Pangam, Suresh; Ponaganti, Srinivas; Krishna, Jayarama; Sujana, Kolla V; Komanduri, Priya K [American Oncology Institute, Hyderabad, Telangana (India)

    2016-06-15

    Purpose: 1. online verification of patient position during treatment using calypso electromagnetic localization and tracking system. 2. Verification and comparison of positional accuracy between cone beam computed tomography and calypso system. 3. Presenting the advantage of continuation localization in Stereotactic radiosurgery treatments. Methods: Ten brain tumor cases were taken for this study. Patients with head mask were under gone Computed Tomography (CT). Before scanning, mask was cut on the fore head area to keep surface beacons on the skin. Slice thickness of 0.65 mm were taken for this study. x, y, z coordinates of these beacons in TPS were entered into tracking station. Varian True Beam accelerator, equipped with On Board Imager was used to take Cone beam Computed Tomography (CBCT) to localize the patient. Simultaneously Surface beacons were used to localize and track the patient throughout the treatment. The localization values were compared in both systems. For localization CBCT considered as reference. Tracking was done throughout the treatment using Calypso tracking system using electromagnetic array. This array was in tracking position during imaging and treatment. Flattening Filter free beams of 6MV photons along with Volumetric Modulated Arc Therapy was used for the treatment. The patient movement was observed throughout the treatment ranging from 2 min to 4 min. Results: The average variation observed between calypso system and CBCT localization was less than 0.5 mm. These variations were due to manual errors while keeping beacon on the patient. Less than 0.05 cm intra-fraction motion was observed throughout the treatment with the help of continuous tracking. Conclusion: Calypso target localization system is one of the finest tools to perform radiosurgery in combination with CBCT. This non radiographic method of tracking is a real beneficial method to treat patients confidently while observing real-time motion information of the patient.

  7. Profile fitting in crowded astronomical images

    Science.gov (United States)

    Manish, Raja

    Around 18,000 known objects currently populate the near Earth space. These constitute active space assets as well as space debris objects. The tracking and cataloging of such objects relies on observations, most of which are ground based. Also, because of the great distance to the objects, only non-resolved object images can be obtained from the observations. Optical systems consist of telescope optics and a detector. Nowadays, usually CCD detectors are used. The information that is sought to be extracted from the frames are the individual object's astrometric position. In order to do so, the center of the object's image on the CCD frame has to be found. However, the observation frames that are read out of the detector are subject to noise. There are three different sources of noise: celestial background sources, the object signal itself and the sensor noise. The noise statistics are usually modeled as Gaussian or Poisson distributed or their combined distribution. In order to achieve a near real time processing, computationally fast and reliable methods for the so-called centroiding are desired; analytical methods are preferred over numerical ones of comparable accuracy. In this work, an analytic method for the centroiding is investigated and compared to numerical methods. Though the work focuses mainly on astronomical images, same principle could be applied on non-celestial images containing similar data. The method is based on minimizing weighted least squared (LS) error between observed data and the theoretical model of point sources in a novel yet simple way. Synthetic image frames have been simulated. The newly developed method is tested in both crowded and non-crowded fields where former needs additional image handling procedures to separate closely packed objects. Subsequent analysis on real celestial images corroborate the effectiveness of the approach.

  8. Astronomers Discover Most Massive Neutron Star Yet Known

    Science.gov (United States)

    2010-10-01

    Astronomers using the National Science Foundation's Green Bank Telescope (GBT) have discovered the most massive neutron star yet found, a discovery with strong and wide-ranging impacts across several fields of physics and astrophysics. "This neutron star is twice as massive as our Sun. This is surprising, and that much mass means that several theoretical models for the internal composition of neutron stars now are ruled out," said Paul Demorest, of the National Radio Astronomy Observatory (NRAO). "This mass measurement also has implications for our understanding of all matter at extremely high densities and many details of nuclear physics," he added. Neutron stars are the superdense "corpses" of massive stars that have exploded as supernovae. With all their mass packed into a sphere the size of a small city, their protons and electrons are crushed together into neutrons. A neutron star can be several times more dense than an atomic nucleus, and a thimbleful of neutron-star material would weigh more than 500 million tons. This tremendous density makes neutron stars an ideal natural "laboratory" for studying the most dense and exotic states of matter known to physics. The scientists used an effect of Albert Einstein's theory of General Relativity to measure the mass of the neutron star and its orbiting companion, a white dwarf star. The neutron star is a pulsar, emitting lighthouse-like beams of radio waves that sweep through space as it rotates. This pulsar, called PSR J1614-2230, spins 317 times per second, and the companion completes an orbit in just under nine days. The pair, some 3,000 light-years distant, are in an orbit seen almost exactly edge-on from Earth. That orientation was the key to making the mass measurement. As the orbit carries the white dwarf directly in front of the pulsar, the radio waves from the pulsar that reach Earth must travel very close to the white dwarf. This close passage causes them to be delayed in their arrival by the distortion of

  9. A combined crossed molecular beams and theoretical study of the reaction CN + C{sub 2}H{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Balucani, Nadia, E-mail: nadia.balucani@unipg.it [Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, Perugia (Italy); Leonori, Francesca; Petrucci, Raffaele [Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, Perugia (Italy); Wang, Xingan [Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, Perugia (Italy); Department of Chemical Physics, University of Science and Technology of China, Hefei 230026 (China); Casavecchia, Piergiorgio [Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, Perugia (Italy); Skouteris, Dimitrios [Scuola Normale Superiore, Pisa (Italy); Albernaz, Alessandra F. [Instituto de Física, Universidade de Brasília, Brasília (Brazil); Gargano, Ricardo [Instituto de Física, Universidade de Brasília, Brasília (Brazil); Departments of Chemistry and Physics, University of Florida, Quantum Theory Project, Gainesville, FL 32611 (United States)

    2015-03-01

    Highlights: • The CN + C{sub 2}H{sub 4} reaction was investigated in crossed beam experiments. • Electronic structure calculations of the potential energy surface were performed. • RRKM estimates qualitatively reproduce the experimental C{sub 2}H{sub 3}NC yield. - Abstract: The CN + C{sub 2}H{sub 4} reaction has been investigated experimentally, in crossed molecular beam (CMB) experiments at the collision energy of 33.4 kJ/mol, and theoretically, by electronic structure calculations of the relevant potential energy surface and Rice–Ramsperger–Kassel–Marcus (RRKM) estimates of the product branching ratio. Differently from previous CMB experiments at lower collision energies, but similarly to a high energy study, we have some indication that a second reaction channel is open at this collision energy, the characteristics of which are consistent with the channel leading to CH{sub 2}CHNC + H. The RRKM estimates using M06L electronic structure calculations qualitatively support the experimental observation of C{sub 2}H{sub 3}NC formation at this and at the higher collision energy of 42.7 kJ/mol of previous experiments.

  10. Astronomical Data Integration Beyond the Virtual Observatory

    Science.gov (United States)

    Lemson, G.; Laurino, O.

    2015-09-01

    "Data integration" generally refers to the process of combining data from different source data bases into a unified view. Much work has been devoted in this area by the International Virtual Observatory Alliance (IVOA), allowing users to discover and access databases through standard protocols. However, different archives present their data through their own schemas and users must still select, filter, and combine data for each archive individually. An important reason for this is that the creation of common data models that satisfy all sub-disciplines is fraught with difficulties. Furthermore it requires a substantial amount of work for data providers to present their data according to some standard representation. We will argue that existing standards allow us to build a data integration framework that works around these problems. The particular framework requires the implementation of the IVOA Table Access Protocol (TAP) only. It uses the newly developed VO data modelling language (VO-DML) specification, which allows one to define extensible object-oriented data models using a subset of UML concepts through a simple XML serialization language. A rich mapping language allows one to describe how instances of VO-DML data models are represented by the TAP service, bridging the possible mismatch between a local archive's schema and some agreed-upon representation of the astronomical domain. In this so called local-as-view approach to data integration, “mediators" use the mapping prescriptions to translate queries phrased in terms of the common schema to the underlying TAP service. This mapping language has a graphical representation, which we expose through a web based graphical “drag-and-drop-and-connect" interface. This service allows any user to map the holdings of any TAP service to the data model(s) of choice. The mappings are defined and stored outside of the data sources themselves, which allows the interface to be used in a kind of crowd-sourcing effort

  11. Astronomers celebrate a year of new Hubble results

    Science.gov (United States)

    1995-02-01

    "We are beginning to understand that because of these observations we are going to have to change the way we look at the Universe," said ESA's Dr Duccio Macchetto, Associate Director for Science Programs at the Space Telescope Science Institute (STScI), Baltimore, Maryland, USA. The European Space Agency plays a major role in the Hubble Space Telescope programme. The Agency provided one of the telescope's four major instruments, called the Faint Object Camera, and two sets of electricity-generating solar arrays. In addition, 15 ESA scientific and technical staff work at the STScI. In return for this contribution, European astronomers are entitled to 15 percent of the telescope's observing time, although currently they account for 20 percent of all observations. "This is a testimony to the quality of the European science community", said Dr Roger Bonnet, Director of Science at ESA. "We are only guaranteed 15 percent of the telescope's use, but consistently receive much more than that." Astronomers from universities, observatories and research institutes across Europe lead more than 60 investigations planned for the telescope's fifth observing cycle, which begins this summer. Many more Europeans contribute to teams led by other astronomers. Looking back to the very start of time European astronomer Dr Peter Jakobsen used ESA's Faint Object Camera to confirm that helium was present in the early Universe. Astronomers had long predicted that 90 percent of the newly born Universe consisted of hydrogen, with helium making up the remainder. Before the refurbished Hubble came along, it was easy to detect the hydrogen, but the primordial helium remained elusive. The ultraviolet capabilities of the telescope, combined with the improvement in spatial resolution following the repair, made it possible for Dr Jakobsen to obtain an image of a quasar close to the edge of the known Universe. A spectral analysis of this picture revealed the quasar's light, which took 13 billion years

  12. Cosmic Blasts Much More Common, Astronomers Discover

    Science.gov (United States)

    2006-08-01

    A cosmic explosion seen last February may have been the "tip of an iceberg," showing that powerful, distant gamma ray bursts are outnumbered ten-to-one by less-energetic cousins, according to an international team of astronomers. The VLA The Very Large Array CREDIT: NRAO/AUI/NSF (Click on image for VLA gallery) A study of the explosion with X-ray and radio telescopes showed that it is "100 times less energetic than gamma ray bursts seen in the distant universe. We were able to see it because it's relatively nearby," said Alicia Soderberg, of Caltech, leader of the research team. The scientists reported their findings in the August 31 issue of the journal Nature. The explosion is called an X-ray flash, and was detected by the Swift satellite on February 18. The astronomers subsequently studied the object using the National Science Foundation's Very Large Array (VLA) radio telescope, NASA's Chandra X-ray Observatory, and the Ryle radio telescope in the UK. "This object tells us that there probably is a rich diversity of cosmic explosions in our local Universe that we only now are starting to detect. These explosions aren't playing by the rules that we thought we understood," said Dale Frail of the National Radio Astronomy Observatory. The February blast seems to fill a gap between ordinary supernova explosions, which leave behind a dense neutron star, and gamma ray bursts, which leave behind a black hole, a concentration of mass so dense that not even light can escape it. Some X-ray flashes, the new research suggests, leave behind a magnetar, a neutron star with a magnetic field 100-1000 times stronger than that of an ordinary neutron star. "This explosion occurred in a galaxy about 470 million light-years away. If it had been at the distances of gamma ray bursts, as much as billions of light-years away, we would not have been able to see it," Frail said. "We think that the principal difference between gamma ray bursts and X-ray flashes and ordinary supernova

  13. Design of a multifunction astronomical CCD camera

    Science.gov (United States)

    Yao, Dalei; Wen, Desheng; Xue, Jianru; Chen, Zhi; Wen, Yan; Jiang, Baotan; Xi, Jiangbo

    2015-07-01

    To satisfy the requirement of the astronomical observation, a novel timing sequence of frame transfer CCD is proposed. The multiple functions such as the adjustments of work pattern, exposure time and frame frequency are achieved. There are four work patterns: normal, standby, zero exposure and test. The adjustment of exposure time can set multiple exposure time according to the astronomical observation. The fame frequency can be adjusted when dark target is imaged and the maximum exposure time cannot satisfy the requirement. On the design of the video processing, offset correction and adjustment of multiple gains are proposed. Offset correction is used for eliminating the fixed pattern noise of CCD. Three gains pattern can improve the signal to noise ratio of astronomical observation. Finally, the images in different situations are collected and the system readout noise is calculated. The calculation results show that the designs in this paper are practicable.

  14. Decoding the mechanisms of Antikythera astronomical device

    CERN Document Server

    Lin, Jian-Liang

    2016-01-01

    This book presents a systematic design methodology for decoding the interior structure of the Antikythera mechanism, an astronomical device from ancient Greece. The historical background, surviving evidence and reconstructions of the mechanism are introduced, and the historical development of astronomical achievements and various astronomical instruments are investigated. Pursuing an approach based on the conceptual design of modern mechanisms and bearing in mind the standards of science and technology at the time, all feasible designs of the six lost/incomplete/unclear subsystems are synthesized as illustrated examples, and 48 feasible designs of the complete interior structure are presented. This approach provides not only a logical tool for applying modern mechanical engineering knowledge to the reconstruction of the Antikythera mechanism, but also an innovative research direction for identifying the original structures of the mechanism in the future. In short, the book offers valuable new insights for all...

  15. Romanian Astronomical Activity in the Middle Ages

    Science.gov (United States)

    Stavinschi, Magdalena; Mioc, Vasile

    The authors describe the main astronomical events and personalities in Romania since th Middle Ages, which begun aproximately at the threeshold between the first and second milleniums of ours era and ends only at the beggining of the 19-th century. The contributions by Ioan Vitez, Ioan Honterus, Conrad Haas, Sevastos Kymnitis, Israel Hubner, Constantin Cantacuzino, Hrisant Notara, Nicolae Mavrocordat, Maximilian Hell, Ignatius Bathyanni, Iosif Bede are underlined. The main contacts of Romanian astronomers with foreigners in such areas as teaching and observations are mentioned. The existing today museums of astronomical instruments are also mentioned. Bibliography: 4. The authors ommit to mention in the bibliography the outstanding book by George Stefan Andonie, concerning the History of Mathematics in Romania as well as few other sources.

  16. Thirteenth Joint European and National Astronomical Meeting

    CERN Document Server

    Iniesta, J C

    2006-01-01

    The book gathers the invited talks to the XIII JENAM conference, organized this time by the European Astronomical Society (EAS) and the Spanish Astronomical Society (SEA), and hosted by the Instituto de Astrofísica de Andalucía (CSIC). All branches of astrophysics are encompassed from the largest scales and cosmology to the solar system and the Sun, through the galaxies and the stars, including a section on astronomical instrumentation. Very relevant experts from all over the world speak in a single book about the most recent, exciting results from their fields in a way which is useful for both researchers in these fields and colleagues working in other disciplines. The book is accompanied by a CD-ROM including the remaining contributions of the meeting in PDF format, hence opening a wide panorama of what is going on in astrophysics nowadays.

  17. Ancient Maya astronomical tables from Xultun, Guatemala.

    Science.gov (United States)

    Saturno, William A; Stuart, David; Aveni, Anthony F; Rossi, Franco

    2012-05-11

    Maya astronomical tables are recognized in bark-paper books from the Late Postclassic period (1300 to 1521 C.E.), but Classic period (200 to 900 C.E.) precursors have not been found. In 2011, a small painted room was excavated at the extensive ancient Maya ruins of Xultun, Guatemala, dating to the early 9th century C.E. The walls and ceiling of the room are painted with several human figures. Two walls also display a large number of delicate black, red, and incised hieroglyphs. Many of these hieroglyphs are calendrical in nature and relate astronomical computations, including at least two tables concerning the movement of the Moon, and perhaps Mars and Venus. These apparently represent early astronomical tables and may shed light on the later books.

  18. The Astronomical Society of New York

    Science.gov (United States)

    Philip, A. G. D.

    2000-05-01

    The New York Astronomical Corporation was formed in 1968 by astronomers at New York State universities, colleges and observatories with the aim of building a large telescope for the use of astronomers in the state. Hawaii was selected as a possible site for a 150-in telescope and for a period of five years a vigorous effort was made at fund raising. A grant was received from the New York State Science and Technology Foundation to help in the organization of the group. By 1973 it was decided to stop plans for a New York Telescope since we had no success in the fund raising. However our group was already involved in holding meetings at the member institutions and staff and students would give reports on their work. In 1973 we formally set up the Astronomical Society of New York. Meetings are held twice a year. The Fall meeting is held at Union College or RPI and at this time the business meeting of NYAC is held. The Spring meeting is held at the other member institutions, from Alfred University in the west and the State University of New York at Stony Brook, in the east. The proceedings of the meetings are published in the News Letter of the Astronomical Society of New York. Prizes are awarded for the best graduate and the best undergraduate papers submitted to the Prize Committee. The winners give invited talks at a meeting following the award. Travel grants are awarded to both graduate and undergraduate students who are granted time to observe on optical or radio telescopes. ASNY has provided a good platform for students to give their first papers and by awarding the prizes and travel grants ASNY has been able to support student research. The meetings help to maintain good contacts among New York astronomers.

  19. Novel Algorithms for Astronomical Plate Analyses

    Czech Academy of Sciences Publication Activity Database

    Hudec, René; Hudec, L.

    2011-01-01

    Roč. 32, 1-2 (2011), s. 121-123 ISSN 0250-6335. [Conference on Multiwavelength Variability of Blazars. Guangzhou, 22,09,2010-24,09,2010] R&D Projects: GA ČR GA205/08/1207 Grant - others:GA ČR(CZ) GA102/09/0997; MŠMT(CZ) ME09027 Institutional research plan: CEZ:AV0Z10030501 Keywords : astronomical plates * plate archives archives * astronomical algorithms Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.400, year: 2011

  20. Astronomical Network for Teachers in Thailand

    Science.gov (United States)

    Kramer (Hutawarakorn), Busaba; Soonthornthum, Boonraksar; Poshyachinda, Saran

    We report the latest development of a pilot project in establishing the astronomical network for teachers in Thailand. The project has been recently granted by the Institute for the Promotion of Teaching Science and Technology Thailand and operated by Sirindhorn Observatory Chiangmai University. The objectives of the project are (1) to establish a16-inch semi-robotic telescope which can be accessed from schools nationwide; and (2) to establish an educational website in Thai language which contains electronic textbook of astronomy online encyclopedia of astronomy observing projects astronomical database and links to other educational websites worldwide. The network will play important role in the development of teaching and learning astronomy in Thailand.

  1. Combined experimental and numerical investigation of energy harness utilizing vortex induced vibration over half cylinder using piezoelectric beams

    Science.gov (United States)

    Ahmed, Md. Tusher; Hossain, Md. Tanver; Rahman, Md. Ashiqur

    2017-06-01

    Energy harvesting technology has the ability to create self-powered electronic systems that do not rely on battery power for their operation. Wind energy can be converted into electricity via a piezoelectric transducer during the air flow over a cylinder. The vortex-induced vibration over the cylinder causes the piezoelectric beam to vibrate. Thus useful electric energy at the range 0.2-0.3V is found which can be useful for self-powering small electronic devices. In the present study, prototypes of micro-energy harvester with a shape of 65 mm × 37 mm × 0.4 mm are developed and tested for airflow over D-shaped bluff body for diameters of 15, 20 and 28mm in an experimental setup consisting of a long wind tunnel of 57cm × 57cm with variable speeds of the motor for different flow velocities and the experimental setup is connected at the downstream where flow velocity is the maximum. Experimental results show that the velocity and induced voltage follows a regular linear pattern. A maximum electrical potential of 140 mV for velocity of 1.1 ms-1 at a bluff body diameter of 15 mm is observed in the energy harvester that can be applied in many practical cases for self-powering electronic devices. The simulation of this energy harvesting phenomena is then simulated using COMSOLE multi-physics. Diameter of the bluff bodies as well as flow velocity and size of cantilever beam are varied and the experimental findings are found to be in good agreement with the simulated ones. The simulations along with the experimental data show the possibility of generating electricity from vortex induced vibration and can be applied in many practical cases for self-powering electronic devices.

  2. Combined photon-electron beams in the treatment of the supraclavicular lymph nodes in breast cancer: A novel technique that achieves adequate coverage while reducing lung dose

    Energy Technology Data Exchange (ETDEWEB)

    Salem, Ahmed, E-mail: ahmed.salem@doctors.org.uk [Department of Radiation Oncology, King Hussein Cancer Center, Amman (Jordan); Mohamad, Issa; Dayyat, Abdulmajeed [Department of Radiation Oncology, King Hussein Cancer Center, Amman (Jordan); Kanaa’n, Haitham [Section of Medical Physics, Department of Radiation Oncology, King Hussein Cancer Center, Amman (Jordan); Sarhan, Nasim [Department of Radiation Oncology, King Hussein Cancer Center, Amman (Jordan); Roujob, Ibrahim [Section of Medical Physics, Department of Radiation Oncology, King Hussein Cancer Center, Amman (Jordan); Salem, Abdel-Fattah [Department of Obstetrics and Gynecology, Hashemite University, Zarqa (Jordan); Afifi, Shatha [Section of Medical Physics, Department of Radiation Oncology, King Hussein Cancer Center, Amman (Jordan); Jaradat, Imad; Mubiden, Rasmi; Almousa, Abdelateif [Department of Radiation Oncology, King Hussein Cancer Center, Amman (Jordan)

    2015-10-01

    Radiation pneumonitis is a well-documented side effect of radiation therapy for breast cancer. The purpose of this study was to compare combined photon-electron, photon-only, and electron-only plans in the radiation treatment of the supraclavicular lymph nodes. In total, 13 patients requiring chest wall and supraclavicular nodal irradiation were planned retrospectively using combined photon-electron, photon-only, and electron-only supraclavicular beams. A dose of 50 Gy over 25 fractions was prescribed. Chest wall irradiation parameters were fixed for all plans. The goal of this planning effort was to cover 95% of the supraclavicular clinical target volume (CTV) with 95% of the prescribed dose and to minimize the volume receiving ≥ 105% of the dose. Comparative end points were supraclavicular CTV coverage (volume covered by the 95% isodose line), hotspot volume, maximum radiation dose, contralateral breast dose, mean total lung dose, total lung volume percentage receiving at least 20 Gy (V{sub 20} {sub Gy}), heart volume percentage receiving at least 25 Gy (V{sub 25} {sub Gy}). Electron and photon energies ranged from 8 to 18 MeV and 4 to 6 MV, respectively. The ratio of photon-to-electron fractions in combined beams ranged from 5:20 to 15:10. Supraclavicular nodal coverage was highest in photon-only (mean = 96.2 ± 3.5%) followed closely by combined photon-electron (mean = 94.2 ± 2.5%) and lowest in electron-only plans (mean = 81.7 ± 14.8%, p < 0.001). The volume of tissue receiving ≥ 105% of the prescription dose was higher in the electron-only (mean = 69.7 ± 56.1 cm{sup 3}) as opposed to combined photon-electron (mean = 50.8 ± 40.9 cm{sup 3}) and photon-only beams (mean = 32.2 ± 28.1 cm{sup 3}, p = 0.114). Heart V{sub 25} {sub Gy} was not statistically different among the plans (p = 0.999). Total lung V{sub 20} {sub Gy} was lowest in electron-only (mean = 10.9 ± 2.3%) followed by combined photon-electron (mean = 13.8 ± 2.3%) and highest in photon

  3. The Virtual Astronomical Observatory Users Forum

    Science.gov (United States)

    Muench, August A.; Emery Bunn, S.; Astronomical Observatory, Virtual

    2013-01-01

    We present the online forum astrobabel.com, which has the goal of being a gathering place for the collective community intelligence about astronomical computing. The audience for this forum is anyone engaged in the analysis of astronomical or planetary data, whether that data be observational or theoretical. It is a free, community driven site where discussions are formulated primarily around the "question and answer" format. Current topics on the forum range from “Is there a photometry package in Python?” to “Where are the support forums for astronomy software packages?” and “Why is my SDSS SkyQuery query missing galaxies?” The poster will detail the full scope of discussions in the forum, and provide some basic guidelines for ensuring high quality forum posts. We will highlight the ways astronomers can discover and participate in discussions. Further, we view this as an excellent opportunity to gather feedback and feature requests from AAS221 attendees. Acknowledgement: The Virtual Astronomical Observatory (VAO) is managed by the VAO, LLC, a non-profit company established as a partnership of the Associated Universities, Inc. and the Association of Universities for Research in Astronomy, Inc. The VAO is sponsored by the National Science Foundation and the National Aeronautics and Space Administration.

  4. Astronomía en la cultura

    Science.gov (United States)

    López, A.; Giménez Benitez, S.; Fernández, L.

    La Astronomía en la Cultura es el estudio interdisciplinario a nivel global de la astronomía prehistórica, antigua y tradicional, en el marco de su contexto cultural. Esta disciplina abarca cualquier tipo de estudios o líneas de investigación en que se relacione a la astronomía con las ciencias humanas o sociales. En ella se incluyen tanto fuentes escritas, relatos orales como fuentes arqueológicas, abarcando entre otros, los siguientes temas: calendarios, observación práctica, cultos y mitos, representación simbólica de eventos, conceptos y objetos astronómicos, orientación astronómica de tumbas, templos, santuarios y centros urbanos, cosmología tradicional y la aplicación ceremonial de tradiciones astronómicas, la propia historia de la astronomía y la etnoastronomía (Krupp, 1989) (Iwaniszewski, 1994). En nuestro trabajo abordamos la historia y situación actual de esta disciplina, sus métodos y sus relaciones con otras áreas de investigación.

  5. Astronomical Plate Archives and Binary Blazars Studies

    Indian Academy of Sciences (India)

    There are about 3 million astronomical photographic plates around the globe, representing an important data source for various aspects of astrophysics. The main advantage is the large time coverage of 100 years or even more. Recent digitization efforts, together with the development of dedicated software, enables for the ...

  6. Astronomers Detect Powerful Bursting Radio Source Discovery Points to New Class of Astronomical Objects

    Science.gov (United States)

    2005-03-01

    Astronomers at Sweet Briar College and the Naval Research Laboratory (NRL) have detected a powerful new bursting radio source whose unique properties suggest the discovery of a new class of astronomical objects. The researchers have monitored the center of the Milky Way Galaxy for several years and reveal their findings in the March 3, 2005 edition of the journal, “Nature”. This radio image of the central region of the Milky Way Galaxy holds a new radio source, GCRT J1745-3009. The arrow points to an expanding ring of debris expelled by a supernova. CREDIT: N.E. Kassim et al., Naval Research Laboratory, NRAO/AUI/NSF Principal investigator, Dr. Scott Hyman, professor of physics at Sweet Briar College, said the discovery came after analyzing some additional observations from 2002 provided by researchers at Northwestern University. “"We hit the jackpot!” Hyman said referring to the observations. “An image of the Galactic center, made by collecting radio waves of about 1-meter in wavelength, revealed multiple bursts from the source during a seven-hour period from Sept. 30 to Oct. 1, 2002 — five bursts in fact, and repeating at remarkably constant intervals.” Hyman, four Sweet Briar students, and his NRL collaborators, Drs. Namir Kassim and Joseph Lazio, happened upon transient emission from two radio sources while studying the Galactic center in 1998. This prompted the team to propose an ongoing monitoring program using the National Science Foundation’s Very Large Array (VLA) radio telescope in New Mexico. The National Radio Astronomy Observatory, which operates the VLA, approved the program. The data collected, laid the groundwork for the detection of the new radio source. “Amazingly, even though the sky is known to be full of transient objects emitting at X- and gamma-ray wavelengths,” NRL astronomer Dr. Joseph Lazio pointed out, “very little has been done to look for radio bursts, which are often easier for astronomical objects to produce

  7. Matrix-mediated biomineralization in marine mollusks: a combined transmission electron microscopy and focused ion beam approach.

    Science.gov (United States)

    Saunders, Martin; Kong, Charlie; Shaw, Jeremy A; Clode, Peta L

    2011-04-01

    The teeth of the marine mollusk Acanthopleura hirtosa are an excellent example of a complex, organic, matrix-mediated biomineral, with the fully mineralized teeth comprising layers of iron oxide and iron oxyhydroxide minerals around a calcium apatite core. To investigate the relationship between the various mineral layers and the organic matrix fibers on which they grew, sections have been prepared from specific features in the teeth at controlled orientations using focused ion beam processing. Compositional and microstructural details of heterophase interfaces, and the fate of the organic matrix fibers within the mineral layers, can then be analyzed by a range of transmission electron microscopy (TEM) techniques. Energy-filtered TEM highlights the interlocking nature of the various mineral phases, while high-angle annular dark-field scanning TEM imaging demonstrates that the organic matrix continues to exist in the fully mineralized teeth. These new insights into the structure of this complex biomaterial are an important step in understanding the relationship between its structural and physical properties and may help explain its high strength and crack-resistance behavior.

  8. Combined elemental analysis of ancient glass beads by means of ion beam, portable XRF, and EPMA techniques.

    Science.gov (United States)

    Sokaras, D; Karydas, A G; Oikonomou, A; Zacharias, N; Beltsios, K; Kantarelou, V

    2009-12-01

    Ion beam analysis (IBA)- and X-ray fluorescence (XRF)-based techniques have been well adopted in cultural-heritage-related analytical studies covering a wide range of diagnostic role, i.e., from screening purposes up to full quantitative characterization. In this work, a systematic research was carried out towards the identification and evaluation of the advantages and the limitations of laboratory-based (IBA, electron probe microanalyzer) and portable (milli-XRF and micro-XRF) techniques. The study focused on the analysis of an Archaic glass bead collection recently excavated from the city of Thebes (mainland, Greece), in order to suggest an optimized and synergistic analytical methodology for similar studies and to assess the reliability of the quantification procedure of analyses conducted in particular by portable XRF spectrometers. All the employed analytical techniques and methodologies proved efficient to provide in a consistent way characterization of the glass bead composition, with analytical range and sensitivity depending on the particular technique. The obtained compositional data suggest a solid basis for the understanding of the main technological features related to the raw major and minor materials utilized for the manufacture of the Thebian ancient glass bead collection.

  9. Relationship between the position of the mental foramen and the anterior loop of the inferior alveolar nerve as determined by cone beam computed tomography combined with mimics.

    Science.gov (United States)

    Chen, Zhuogeng; Chen, Donghui; Tang, Li; Wang, Fenfen

    2015-01-01

    The position of the mental foramen and the anterior loop length of the inferior alveolar nerve serve as important anatomical landmarks for surgical procedures in the anterior mandibular region. The purpose of this study was to determine the relationship between the anterior loop of the inferior alveolar nerve and the mental foramen by combining cone beam computed tomography and Mimics, a software used to construct 3-dimensional (3D) interactive models of anatomical structures. Cone beam computed tomography images from a total of 60 patients were obtained and studied using GALAXY viewer or were imported into Mimics. The anterior loop of the inferior alveolar nerve was reconstructed 3-dimensionally, and then relevant parameters were measured. The parameters were measured, and their values include mean (SD) anterior loop length, 1.16 (1.78) mm; anterior loop angle, 19.13 (26.89) degrees; inferior alveolar canal diameter, 3.01 (0.67) mm; height of the inferior alveolar canal, 10.32 (1.56) mm; 2-dimensional mental foramen diameter, 2.97 (0.61) mm; 3D mental foramen diameter, 2.95 (0.59) mm; 2-dimensional vertical height of the mental foramen, 14.67 (1.67) mm; and 3D vertical height of the mental foramen, 14.61 (1.69) mm. The mental foramen was located apically between the first and second premolars in 51.67% and below the second premolar in 40.83% of the cases. A relationship was observed between the location of the mental foramen and the presence of the anterior loop of the inferior alveolar nerve. We highlight the effectiveness of cone beam computed tomography and 3D reconstruction in the identification of important anatomical structures relevant for preoperative assessment for surgical procedures in the anterior region of the mandible.

  10. Sociological Profile of Astronomers in Spain

    Science.gov (United States)

    Iglesias de Ussel, Julio; Trinidad, Antonio; Ruiz, Diego; Battaner, Eduardo; Delgado, Antonio J.; Rodriguez-Espinosa, José M.; Salvador-Solé, Eduard; Torrelles, José M.

    In this paper the main findings are presented of a recent study made by a team of sociologists from the University of Granada on the professional astronomers currently working in Spain. Despite the peculiarities of this group - its youth, twentyfold increase in size over the last 20 years, and extremely high rate of specialization abroad - in comparison with other Spanish professionals, this is the first time that the sociological characteristics of the group have been studied discretely. The most significant results of the study are presented in the following sections. Section 1 gives a brief historical background of the development of Astronomy in Spain. Section 2 analyzes the socio-demographic profile of Spanish Astronomy professionals (sex, age, marital status, etc.). Sections 3-5 are devoted to the college education and study programs followed by Spanish astronomers, focusing on the features and evaluations of the training received, and pre- and postdoctoral study trips made to research centers abroad. The results for the latter clearly show the importance that Spanish astronomers place on having experience abroad. Special attention is paid to scientific papers published as a result of joint research projects carried out with colleagues from centers abroad as a result of these study trips. Section 6 describes the situation of Astronomy professionals within the Spanish job market, the different positions available and the time taken to find a job after graduation. Section 7 examines Astronomy as a discipline in Spain, including the astronomers' own opinions of the social status of the discipline within Spanish society. Particular attention is paid to how Spanish astronomers view the status of Astronomy in Spain in comparison with that of other European countries.

  11. Direct writing of gold nanostructures with an electron beam: On the way to pure nanostructures by combining optimized deposition with oxygen-plasma treatment

    Directory of Open Access Journals (Sweden)

    Domagoj Belić

    2017-11-01

    Full Text Available This work presents a highly effective approach for the chemical purification of directly written 2D and 3D gold nanostructures suitable for plasmonics, biomolecule immobilisation, and nanoelectronics. Gold nano- and microstructures can be fabricated by one-step direct-write lithography process using focused electron beam induced deposition (FEBID. Typically, as-deposited gold nanostructures suffer from a low Au content and unacceptably high carbon contamination. We show that the undesirable carbon contamination can be diminished using a two-step process – a combination of optimized deposition followed by appropriate postdeposition cleaning. Starting from the common metal-organic precursor Me2-Au-tfac, it is demonstrated that the Au content in pristine FEBID nanostructures can be increased from 30 atom % to as much as 72 atom %, depending on the sustained electron beam dose. As a second step, oxygen-plasma treatment is established to further enhance the Au content in the structures, while preserving their morphology to a high degree. This two-step process represents a simple, feasible and high-throughput method for direct writing of purer gold nanostructures that can enable their future use for demanding applications.

  12. Direct writing of gold nanostructures with an electron beam: On the way to pure nanostructures by combining optimized deposition with oxygen-plasma treatment.

    Science.gov (United States)

    Belić, Domagoj; Shawrav, Mostafa M; Bertagnolli, Emmerich; Wanzenboeck, Heinz D

    2017-01-01

    This work presents a highly effective approach for the chemical purification of directly written 2D and 3D gold nanostructures suitable for plasmonics, biomolecule immobilisation, and nanoelectronics. Gold nano- and microstructures can be fabricated by one-step direct-write lithography process using focused electron beam induced deposition (FEBID). Typically, as-deposited gold nanostructures suffer from a low Au content and unacceptably high carbon contamination. We show that the undesirable carbon contamination can be diminished using a two-step process - a combination of optimized deposition followed by appropriate postdeposition cleaning. Starting from the common metal-organic precursor Me2-Au-tfac, it is demonstrated that the Au content in pristine FEBID nanostructures can be increased from 30 atom % to as much as 72 atom %, depending on the sustained electron beam dose. As a second step, oxygen-plasma treatment is established to further enhance the Au content in the structures, while preserving their morphology to a high degree. This two-step process represents a simple, feasible and high-throughput method for direct writing of purer gold nanostructures that can enable their future use for demanding applications.

  13. Finding Hidden Treasures: Investigations in US Astronomical Plate Archives

    Directory of Open Access Journals (Sweden)

    René Hudec

    2013-01-01

    Full Text Available We report here on an ongoing investigation of US astronomical plate archives and tests of the suitability of transportable scanning devices for in situ digitization of archival astronomical plates.

  14. The Virtual Astronomical Observatory: Re-engineering access to astronomical data

    OpenAIRE

    Hanisch, R. J.; Berriman, G. B.; Lazio, T. J. W.; Emery Bunn, S.; Evans, J; McGlynn, T. A.; Plante, R.

    2015-01-01

    The US Virtual Astronomical Observatory was a software infrastructure and development project designed both to begin the establishment of an operational Virtual Observatory (VO) and to provide the US coordination with the international VO effort. The concept of the VO is to provide the means by which an astronomer is able to discover, access, and process data seamlessly, regardless of its physical location. This paper describes the origins of the VAO, including the predecessor efforts within ...

  15. In situ investigation of the surface silvering of late Roman coins by combined use of high energy broad-beam and low energy micro-beam X-ray fluorescence techniques

    Energy Technology Data Exchange (ETDEWEB)

    Romano, F.P., E-mail: romanop@lns.infn.it [IBAM, CNR, Via Biblioteca 4, 95124 Catania (Italy); LNS, INFN, Via S. Sofia 62, 95123 Catania (Italy); Garraffo, S. [ITABC, CNR, Via Salaria km 29.300, 00016 Monterotondo, Roma (Italy); Pappalardo, L. [IBAM, CNR, Via Biblioteca 4, 95124 Catania (Italy); LNS, INFN, Via S. Sofia 62, 95123 Catania (Italy); Rizzo, F. [LNS, INFN, Via S. Sofia 62, 95123 Catania (Italy); Dipartimento di Fisica e Astronomia, Universita di Catania, Via S. Sofia 64, 95123 Catania (Italy)

    2012-07-15

    The compositional analysis of archeological metals performed with the X-ray Fluorescence technique (XRF) provides information on the ancient technology. One of the most interesting case-study concerns the techniques used by Romans for silvering the surface of coins. Different metallurgical processes have been suggested in previous studies. Recently the investigation has been addressed to the mercury-silvering and to its possible use in the mass-production of coins minted during the late period (after 294 AD). In the present paper the non-destructive investigation of the silvering process used for manufacturing the Roman nummi - the important typology of coin introduced by Diocletian in his monetary reform - is approached by the combined use of the standard X-Ray Fluorescence (XRF) and the low energy micro-X-Ray Fluorescence (LE-{mu}XRF) portable methods. The research was focused on the systematic determination of the mercury presence in a large number of samples and on its correlation with silver in the surface of the coins. 1041 Roman nummi belonging to the Misurata Treasure were analyzed in situ, at the Leptis Magna Museum (Al Khums, Libya). The treasure, composed of about 108 thousand silvered coins, gives the unique opportunity to study the Roman coinage in a wide interval of time (about 40 years in the period 294-333 AD) and in almost all the imperial mints operating in the Roman world. - Highlights: Black-Right-Pointing-Pointer Custom-building of a high energy broad-beam and a low energy micro-beam XRF Black-Right-Pointing-Pointer In situ analysis of the silvering methods in late Roman nummi with plated surfaces Black-Right-Pointing-Pointer The broad-beam XRF was applied for the detection of mercury traces in the coin alloy. Black-Right-Pointing-Pointer The low energy micro-XRF was used to scan the surface patina of the coins. Black-Right-Pointing-Pointer The correlation between mercury and silver at the coin surface was evidenced.

  16. Astronomical Orientation of Pyramid Tombs in North China

    Science.gov (United States)

    Rusell Tiede, Vance

    2010-01-01

    Two ancient Chinese texts, the Chou Bei Suan Ching and Chou Li (Western Han Dynasty, ca. 100 BC), record that the Imperial Astronomer (Feng Hsian Shin) made solar observations to determine the solstices and equinoxes, and for determining the cardinal directions with a circle and gnomon. By combining the techniques of astro-archaeology (G. S. Hawkins, 1968) with both overhead imagery and ground survey, the present study seeks to link historical Chinese descriptions of astronomical phenomena with contemporary architectural orientation. In the process, several unexpected astronomical orientation patterns emerged which apparently do not appear in the surviving historical record. For example, at the imperial Western Han capital of Ch'ang-an (N 34° latitude), the diagonals of cardinally oriented square pyramid mounds (ling) align to zenith (+34° declination) and nadir (-34° declination) star rise and set points on the skyline. This is in accord with the Chou (Zhou) Dynasty's name of Chung-Kuo, meaning Central Country or Middle Kingdom. That is, the imperial capital is centered both politico-geographically with respect to its vassal states of the Eastern Yi, Southern Man, Western Rong, and Northern Di, as well as astro-geomantically regarding the color-coded Five Sacred Directions East-South-West-North-Zenith/Nadir in the Cosmos. Our ground survey also confirmed pyramid orientation to the lunar standstills (+28°, +18° and +5° declination) that we reported from overhead imagery in 1980 (155th AAS Meeting, HAD 18.CE.12, Lunar and Solar Alignments of Ancient Chinese Pyramids). Grateful acknowledgment is given to the Chinese Academy of Sciences for the invitation to conduct an astro-archaeological survey of the Wei-ho valley, Shensi (Shaanxi) Province.

  17. New flexible origination technology based on electron-beam lithography and its integration into security devices in combination with covert features based on DNA authentication

    Science.gov (United States)

    Drinkwater, John K.; Ryzi, Zbynek; Outwater, Chris S.

    2002-04-01

    Embossed diffractive optically variable devices are becoming increasingly familiar security items on plastic cards, banknotes, security documents and on branded goods and media to protect against counterfeit, protect copyright and to evidence tamper. Equally as this devices become both more widely available there is a pressing requirement for security technology upgrades to keep ahead of technology advances available to potential counterfeiters. This paper describes a new generation electron beam DOVID origination technology particularly suitable for high security applications. Covert marking of security devices is provided using the DNA matrix by creating and verifying unique DNA sequences. This integration of this into practical security features in combination with covert features based on DNA matrix authentication and other more straightforwardly authenticable features to provide multi- technology security solutions will be described.

  18. Tilted pillar array fabrication by the combination of proton beam writing and soft lithography for microfluidic cell capture Part 2: Image sequence analysis based evaluation and biological application.

    Science.gov (United States)

    Járvás, Gábor; Varga, Tamás; Szigeti, Márton; Hajba, László; Fürjes, Péter; Rajta, István; Guttman, András

    2017-07-17

    As a continuation of our previously published work, this paper presents a detailed evaluation of a microfabricated cell capture device utilizing a doubly tilted micropillar array. The device was fabricated using a novel hybrid technology based on the combination of proton beam writing and conventional lithography techniques. Tilted pillars offer unique flow characteristics and support enhanced fluidic interaction for improved immunoaffinity based cell capture. The performance of the microdevice was evaluated by an image sequence analysis based in-house developed single-cell tracking system. Individual cell tracking allowed in-depth analysis of the cell-chip surface interaction mechanism from hydrodynamic point of view. Simulation results were validated by using the hybrid device and the optimized surface functionalization procedure. Finally, the cell capture capability of this new generation microdevice was demonstrated by efficiently arresting cells from a HT29 cell-line suspension. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Pretreatment Endorectal Coil Magnetic Resonance Imaging Findings Predict Biochemical Tumor Control in Prostate Cancer Patients Treated With Combination Brachytherapy and External-Beam Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Riaz, Nadeem [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Afaq, Asim; Akin, Oguz [Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Pei Xin; Kollmeier, Marisa A.; Cox, Brett [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Hricak, Hedvig [Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Zelefsky, Michael J., E-mail: zelefskm@mskcc.org [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)

    2012-11-01

    Purpose: To investigate the utility of endorectal coil magenetic resonance imaging (eMRI) in predicting biochemical relapse in prostate cancer patients treated with combination brachytherapy and external-beam radiotherapy. Methods and Materials: Between 2000 and 2008, 279 men with intermediate- or high-risk prostate cancer underwent eMRI of their prostate before receiving brachytherapy and supplemental intensity-modulated radiotherapy. Endorectal coil MRI was performed before treatment and retrospectively reviewed by two radiologists experienced in genitourinary MRI. Image-based variables, including tumor diameter, location, number of sextants involved, and the presence of extracapsular extension (ECE), were incorporated with other established clinical variables to predict biochemical control outcomes. The median follow-up was 49 months (range, 1-13 years). Results: The 5-year biochemical relapse-free survival for the cohort was 92%. Clinical findings predicting recurrence on univariate analysis included Gleason score (hazard ratio [HR] 3.6, p = 0.001), PSA (HR 1.04, p = 0.005), and National Comprehensive Cancer Network risk group (HR 4.1, p = 0.002). Clinical T stage and the use of androgen deprivation therapy were not correlated with biochemical failure. Imaging findings on univariate analysis associated with relapse included ECE on MRI (HR 3.79, p = 0.003), tumor size (HR 2.58, p = 0.04), and T stage (HR 1.71, p = 0.004). On multivariate analysis incorporating both clinical and imaging findings, only ECE on MRI and Gleason score were independent predictors of recurrence. Conclusions: Pretreatment eMRI findings predict for biochemical recurrence in intermediate- and high-risk prostate cancer patients treated with combination brachytherapy and external-beam radiotherapy. Gleason score and the presence of ECE on MRI were the only significant predictors of biochemical relapse in this group of patients.

  20. Coherent Beam Combining Element for Five 150-W Fiber Lasers by Volume Bragg Gratings in PTR Glass

    Science.gov (United States)

    2011-08-03

    centimeter, make PTR-glass holograms attractive for high-power laser applications. A volume holographic optical element is an interference pattern...PTR glass……………………………………….. 3 2 Optical scheme of coherent coupling of laser diodes. a) combining of independent diodes, b) spectral locking of LD-1, c...the split beams…………………………………… 14 13 Optical setup for the measurement of the phase shift induced by Laser heating in an optical flat. W: wedge, L

  1. Towards a robust and consistent middle Eocene astronomical timescale

    Science.gov (United States)

    Boulila, Slah; Vahlenkamp, Maximilian; De Vleeschouwer, David; Laskar, Jacques; Yamamoto, Yuhji; Pälike, Heiko; Kirtland Turner, Sandra; Sexton, Philip F.; Westerhold, Thomas; Röhl, Ursula

    2018-03-01

    present a revision of previous astronomical timescales from the Equatorial and South Atlantic, to overcome the differences between different mid-Eocene astrochronologies. Using our new records from the North Atlantic, combined with existing records from the South Atlantic (ODP Site 1263 and Hole 702B) and Equatorial Atlantic (ODP Site 1260), we revise the durations of magnetic polarity Chrons C18n.1n to C21n, thereby arriving at a robust and self-consistent closure of the middle Eocene astronomical timescale gap.

  2. Image-Processing Techniques for the Creation of Presentation-Quality Astronomical Images

    Science.gov (United States)

    Rector, Travis A.; Levay, Zoltan G.; Frattare, Lisa M.; English, Jayanne; Pu'uohau-Pummill, Kirk

    2007-02-01

    The quality of modern astronomical data and the agility of current image-processing software enable the visualization of data in a way that exceeds the traditional definition of an astronomical image. Two developments in particular have led to a fundamental change in how astronomical images can be assembled. First, the availability of high-quality multiwavelength and narrowband data allow for images that do not correspond to the wavelength sensitivity of the human eye, thereby introducing ambiguity in the usage and interpretation of color. Second, many image-processing software packages now use a layering metaphor that allows for any number of astronomical data sets to be combined into a color image. With this technique, images with as many as eight data sets have been produced. Each data set is intensity-scaled and colorized independently, creating an immense parameter space that can be used to assemble the image. Since such images are intended for data visualization, scaling and color schemes must be chosen that best illustrate the science. A practical guide is presented on how to use the layering metaphor to generate publication-ready astronomical images from as many data sets as desired. A methodology is also given on how to use intensity scaling, color, and composition to create contrasts in an image that highlight the scientific detail. Examples of image creation are discussed.

  3. Precise Astronomical Azimuth Determination By Qdaedalus System to the Sun, Moon, and Planets in Daytime Conditions

    Science.gov (United States)

    Völgyesi, L.; Tóth, G.; Bürki, B.; Guillaume, S.

    2014-12-01

    The traditional method of astronomical azimuth determination involves measurements at night to stars (Polaris). QDAEDALUS, developed by the team of the Geodesy and Geodynamics Lab (GGL, led by Prof. M. Rothacher) of ETH Zürich is a unique system combining Total Stations and modern CCD technique. It provides precise astronomical azimuths within 15 minutes of observation time at night. Furthermore, observations in daytime conditions are a challenging requirement in practice of Astro-geodetic azimuth determination. In order to perform daylight measurements, the QDAEDALUS system has been improved by allowing precise azimuth measurements to Sun, Moon, and Planets in daylight conditions by expanding the processing software with precise solar, lunar, and planetary ephemerides. With such functionality the system has a unique capability to measure astronomical azimuths with an accuracy of 0.3-0.5 arcsecs in normal daylight conditions within 20 to 25 minutes of measurement time.

  4. Using Astronomical Photographs to Investigate Misconceptions about Galaxies and Spectra: Question Development for Clicker Use

    CERN Document Server

    Lee, Hyunju

    2015-01-01

    Many topics in introductory astronomy at the college or high-school level rely implicitly on using astronomical photographs and visual data in class. However, students bring many preconceptions to their understanding of these materials that ultimately lead to misconceptions, and research about students' interpretation of astronomical images has been scarcely conducted. In this study we probed college students' understanding of astronomical photographs and visual data about galaxies and spectra, and developed a set of concept questions based on their common misconceptions. The study was conducted mainly in three successive surveys: 1) open-ended questions looking for students' ideas and common misconceptions, 2) combined multiple-choice and open-ended questions seeking to explore student reasoning and to improve concept questions for clickers, and 3) a finalized version of the concept questions used to investigate the strength of each misconception among the students in introductory astronomy courses. This stu...

  5. Revista Mexicana de Astronomía y Astrofísica, a real option for astronomical publication

    Science.gov (United States)

    Torres-Peimbert, S.; Allen, C.

    2011-10-01

    We present statistical data about the Revista Mexicana de Astronomía y Astrofísica. We consider that this journal is well positioned in the international astronomical literature. Similarly we present information about the Serie de Conferencias, which also has a wide level of acceptance by the astronomical community.

  6. Astronomical context coder for image compression

    Science.gov (United States)

    Pata, Petr; Schindler, Jaromir

    2015-10-01

    Recent lossless still image compression formats are powerful tools for compression of all kind of common images (pictures, text, schemes, etc.). Generally, the performance of a compression algorithm depends on its ability to anticipate the image function of the processed image. In other words, a compression algorithm to be successful, it has to take perfectly the advantage of coded image properties. Astronomical data form a special class of images and they have, among general image properties, also some specific characteristics which are unique. If a new coder is able to correctly use the knowledge of these special properties it should lead to its superior performance on this specific class of images at least in terms of the compression ratio. In this work, the novel lossless astronomical image data compression method will be presented. The achievable compression ratio of this new coder will be compared to theoretical lossless compression limit and also to the recent compression standards of the astronomy and general multimedia.

  7. Astronomical Photometry Past, Present, and Future

    CERN Document Server

    Milone, Eugene F

    2011-01-01

    This book brings together experts in the field of astronomical photometry to discuss how their subfields provide the precision and accuracy in astronomical energy flux measurements that are needed to permit tests of astrophysical theories. Differential photometers and photometry, improvements in infrared precision, the improvements in precision and accuracy of CCD photometry, the absolute calibration of flux, the development of the Johnson UBVRI photometric system and other passband systems to measure and precisely classify specific types of stars and astrophysical quantities, and the current capabilities of spectrophotometry and polarimetry to provide precise and accurate data, are all discussed in this volume. The discussion of `differential’ or `two-star’ photometers ranges from early experiments in visual photometry through the Harvard and Princeton polarizing photometers to the pioneering work of Walraven and differential photometers designed to minimize effects of atmospheric extinction and to count...

  8. Astronomical Instrumentation Systems Quality Management Planning: AISQMP

    Science.gov (United States)

    Goldbaum, Jesse

    2017-06-01

    The capability of small aperture astronomical instrumentation systems (AIS) to make meaningful scientific contributions has never been better. The purpose of AIS quality management planning (AISQMP) is to ensure the quality of these contributions such that they are both valid and reliable. The first step involved with AISQMP is to specify objective quality measures not just for the AIS final product, but also for the instrumentation used in its production. The next step is to set up a process to track these measures and control for any unwanted variation. The final step is continual effort applied to reducing variation and obtaining measured values near optimal theoretical performance. This paper provides an overview of AISQMP while focusing on objective quality measures applied to astronomical imaging systems.

  9. Astronomía Mocoví

    Science.gov (United States)

    López, A.; Giménez Benitez, S.; Fernández, L.

    El presente trabajo, es una revisión crítica de la astronomía en la cultura Mocoví, aportando a lo realizado previamente por Lehmann Nistche (Lehmann Nistche, 1924 y 1927) el resultado de nuestro trabajo de campo. Un mayor conocimiento de las cosmovisiones de las etnias de esta área es fundamental para una mejor comprensión de la dispersión de las ideas cosmológicas entre los pueblos aborígenes americanos, dada la importancia del corredor chaqueño como conexión entre las altas culturas andinas, la mesopotamia y la región pampeana (Susnik, 1972). Para ello se realiza una comparación con otras cosmovisiones del área americana. Nuestro aporte se enmarca dentro de las actuales líneas de trabajo mundialmente en desarrollo en Astronomía en la Cultura.

  10. The origins of Ptolemy's astronomical tables.

    Science.gov (United States)

    Newton, R. R.

    Following the line set by his earlier book 'The crime of Claudius Ptolemy' the author discusses here the numerous astronomical tables in Ptolemy's work that have been calculated with the aid of trigonometric tables, as well as a few that are nonlinear but that do not involve trigonometry. The purpose in this study is to determine, if possible, whether Ptolemy calculated these tables or whether he copied them from now-lost original works. The conclusion isthat Ptolemy made few if any original contributions to astronomy, either observational or computational.Contents: 1. Introduction; thetable of chords. 2. The tables of the latitude and of gnomon shadows.3. Tables of the Sun. 4. Astronomical geography. 5. The tables of theMoon. 6. Eclipse tables. 7. Tables of the planets. 8. The empirical basis for Hipparchus's mean motions of the Moon. 9. Summary and conclusions.

  11. WWW Access to Astronomical Archives and Databases

    Science.gov (United States)

    Pasian, Fabio; Smareglia, Riccardo

    In this document, an approach to the development of WWW-accessible astronomical archives and databases is described, which can easily be extended also to other disciplines. The architecture is based on a set of servers running at the archive site, each performing a specialized task: accessing an SQL-based DBMS, retrieving and downlinking 1-D or 2-D data (measurements), displaying quicklook data, or plotting the results of a query to the database. All of the information on the user interface is dynamically stored in the database, allowing the pages to be prepared on-the-fly; no additional software needs to be run on the user’s computer. A WWW-accessible test astronomical archive, containing both 2-D (images) and 1-D (spectra) data, and having NCSA/Mosaic as an interface is described as an example of successful application of the above concepts.

  12. Isaac Newton and the astronomical refraction.

    Science.gov (United States)

    Lehn, Waldemar H

    2008-12-01

    In a short interval toward the end of 1694, Isaac Newton developed two mathematical models for the theory of the astronomical refraction and calculated two refraction tables, but did not publish his theory. Much effort has been expended, starting with Biot in 1836, in the attempt to identify the methods and equations that Newton used. In contrast to previous work, a closed form solution is identified for the refraction integral that reproduces the table for his first model (in which density decays linearly with elevation). The parameters of his second model, which includes the exponential variation of pressure in an isothermal atmosphere, have also been identified by reproducing his results. The implication is clear that in each case Newton had derived exactly the correct equations for the astronomical refraction; furthermore, he was the first to do so.

  13. Statistical methods for astronomical data analysis

    CERN Document Server

    Chattopadhyay, Asis Kumar

    2014-01-01

    This book introduces “Astrostatistics” as a subject in its own right with rewarding examples, including work by the authors with galaxy and Gamma Ray Burst data to engage the reader. This includes a comprehensive blending of Astrophysics and Statistics. The first chapter’s coverage of preliminary concepts and terminologies for astronomical phenomenon will appeal to both Statistics and Astrophysics readers as helpful context. Statistics concepts covered in the book provide a methodological framework. A unique feature is the inclusion of different possible sources of astronomical data, as well as software packages for converting the raw data into appropriate forms for data analysis. Readers can then use the appropriate statistical packages for their particular data analysis needs. The ideas of statistical inference discussed in the book help readers determine how to apply statistical tests. The authors cover different applications of statistical techniques already developed or specifically introduced for ...

  14. Recruitment and Retention of LGBTIQ Astronomers

    Science.gov (United States)

    Dixon, William Van Dyke

    2012-01-01

    While lesbian, gay, bisexual, transgender, intersex, or questioning (LGBTIQ) astronomers face many of the same workplace challenges as women and racial/ethnic minorities, from implicit bias to overt discrimination, other challenges are unique to this group. An obvious example is the absence at many institutions of health insurance and other benefits for the same-sex domestic partners of their employees. More subtle is the psychological toll paid by LGBTIQ astronomers who remain "in the closet," self-censoring every statement about their personal lives. Paradoxically, the culture of the physical sciences, in which sexuality, gender identity, and gender expression are considered irrelevant, can discourage their discussion, further isolating LGBTIQ researchers. Addressing these challenges is not just a matter of fairness; it is an essential tool in the recruitment and retention of the brightest researchers and in assuring their productivity. We will discuss these issues and what individuals and departments can to make their institutions more welcoming to their LGBTIQ colleagues.

  15. International Astronomical Union Sympoisum No.50

    CERN Document Server

    Westerlund, B

    1973-01-01

    Dr J. Landi Dessy, Director of the Astronomical Observatory, Cordoba, Argentina, invited the International Astronomical Union to hold a Symposium in Cordoba in connection with the celebration of the Centennial of the Cordoba Observatory; the date of foundation is October 24, 1871. He proposed that the Symposium should deal with Spectral Classification and Multicolour Photometry as seven years had elapsed since the Symposium No. 24 in Saltsj6baden, and much development had occurred in the field. The invitation and the proposal were accepted by the IAU, and the Symposium was held in Villa Carlos Paz, near Cordoba, between October 18 and October 24, 1971. It was attended by about 50 scientists representing Argentina, Canada, Chile, Den­ mark, France, Germany, Italy, Mexico, Sweden, Switzerland, U.K., U.S.A., Vatican City State and Venezuela. The Symposium was divided into four sessions: 1. Classification of slit spectra, 2. Classification of objective-prism spectra, 3. Photometric classification, 4. Catalogues ...

  16. EDUCATIONAL ASTRONOMICAL OBSERVATIONS ON REMOTE ACCESS TELESCOPES

    Directory of Open Access Journals (Sweden)

    Ivan P. Kriachko

    2016-01-01

    Full Text Available The purpose of this article is to show the way of overcoming one of the major problems of astronomy teaching methods in upper secondary school – organization of educational astronomical observations. Nowadays it became possible to perform such observations on remote access telescopes. By using up-to-date informational and communicational technologies, having an opportunity to work with robotic telescopes allows us to organize a unique cognitive and research oriented activities for students while conducting their specialized astronomical studies. Below here is given a brief description of the most significant robotic telescopes and the way of the usage of open remote access telescopic network which was created by professors and scientists of Harvard-Smithsonian Center for Astrophysics, USA.

  17. Tailored stoichiometries of silicon carbonitride thin films prepared by combined radio frequency magnetron sputtering and ion beam synthesis

    Science.gov (United States)

    Bruns, M.; Geckle, U.; Trouillet, V.; Rudolphi, M.; Baumann, H.

    2005-07-01

    Homogenous Si-C-N films of 120 nm thickness have been successfully fabricated by means of rf magnetron sputtering combined with ion implantation. These means are capable of producing various tailored stoichiometries of so far unequaled nitrogen concentration and high purity (O<0.2 at. %, H<0.5 at. %). The achieved compounds Si2CN4,SiCN2, and SiC2N2.2 consist of SiN4 tetrahedron layers interconnected by carbodiimid bridges. Stoichiometry, chemical binding states, and homogeneity of these layers as well as the reproducibility have been investigated by means of x-ray photoelectron spectroscopy, Fourier transform infrared, non-Rutherford back scattering spectroscopy, and resonant nuclear reaction analyses. Furthermore, sputter induced effects on the Si-C-N system during surface analytical characterization using Ar+ ions at 250 and 3250 eV for sputter cleaning have been studied carefully.

  18. Digitizer of astronomical plates at Shanghai Astronomical Observatory and its performance test

    Science.gov (United States)

    Yu, Yong; Zhao, Jian-Hai; Tang, Zheng-Hong; Shang, Zheng-Jun

    2017-02-01

    Before CCD detectors were widely employed in observational astronomy, the main method of detection was the use of glass astrophotographic plates. Astronomical plates have been used to record information on the position and activity of celestial bodies for more than 100 years. There are about 30 000 astronomical plates in China, and the digitization of astronomical plates is of great significance for permanent preservation and to make full use of these valuable observation data. A digitizer with high precision and high measuring speed is a key piece of equipment for carrying out the task of digitizing these astronomical plates. A digitizer for glass astrophotographic plates was developed jointly by Shanghai Astronomical Observatory and Nishimura Co., Ltd of Japan. The digitizer’s hardware was manufactured by Nishimura Co., Ltd, and the performance test, error corrections as well as image processing of the digitizer were carried out by Shanghai Astronomical Observatory. The main structure and working mode of the digitizer are introduced in this paper. A performance test shows that brightness uniformity of illumination within the measuring area is better than 0.15%, the repeatability of digitized positions is better than 0.2 µm and the repeatability of digitized brightness is better than 0.01 instrumental magnitude. The systematic factors affecting digitized positions, such as lens distortion, the actual optical resolution, non-linearity of guide rails, non-uniformity of linear motors in the mobile platform, deviation of the image mosaic, and non-orthogonality between the direction of scanning and camera linear array, are calibrated and evaluated. Based on an astronomical plate with a size of 300mm × 300mm, which was digitized at different angles, the conversion residuals of positions of common stars on different images were investigated. The results show that the standard deviations of the residuals are better than 0.9 µm and the residual distribution is almost

  19. Astronomical Dating of Monet's Paintings on the Normandy Coast

    Science.gov (United States)

    Olson, D. W.

    2016-01-01

    Claude Monet (1840-1926) is famous for landscapes accurately capturing the changing nature of seas and skies. Monet created almost two thousand paintings during his long career, and several hundred of these works depict the skies above the spectacular cliffs, arches, rocks, harbors, and beaches on the Normandy coast. Our Texas State University group made a research trip to Normandy in the summer of 2012 and found dozens of the locations where Monet set up his easel. Astronomical considerations of daylight, twilight, night skies, and tides can be used to enhance our understanding of the artist's creative process. Monet himself said, “I need the Sun or the cloudy weather to coincide again with the tide, which must be low or high in accordance with my motifs.” Astronomical methods can be used to help in dating these works, many of which have uncertain dates in the existing catalogues and literature about Monet in Normandy. Analysis using the direction of sunlight and the direction of shadows, combined with calculations of lunar phases and tide levels, meteorological records, and the artist's letters, enables us to determine the exact date and the precise time, accurate to the minute, when Monet observed the sky that inspired a painting.

  20. Linear feature detection algorithm for astronomical surveys - I. Algorithm description

    Science.gov (United States)

    Bektešević, Dino; Vinković, Dejan

    2017-11-01

    Computer vision algorithms are powerful tools in astronomical image analyses, especially when automation of object detection and extraction is required. Modern object detection algorithms in astronomy are oriented towards detection of stars and galaxies, ignoring completely the detection of existing linear features. With the emergence of wide-field sky surveys, linear features attract scientific interest as possible trails of fast flybys of near-Earth asteroids and meteors. In this work, we describe a new linear feature detection algorithm designed specifically for implementation in big data astronomy. The algorithm combines a series of algorithmic steps that first remove other objects (stars and galaxies) from the image and then enhance the line to enable more efficient line detection with the Hough algorithm. The rate of false positives is greatly reduced thanks to a step that replaces possible line segments with rectangles and then compares lines fitted to the rectangles with the lines obtained directly from the image. The speed of the algorithm and its applicability in astronomical surveys are also discussed.

  1. Astronomic Bioethics: Terraforming X Planetary protection

    OpenAIRE

    Palhares, Dario; Santos, Íris Almeida dos

    2017-01-01

    A hard difficulty in Astrobiology is the precise definition of what life is. All living beings have a cellular structure, so it is not possible to have a broader concept of life hence the search for extraterrestrial life is restricted to extraterrestrial cells. Earth is an astronomical rarity because it is difficult for a planet to present liquid water on the surface. Two antagonistic bioethical principles arise: planetary protection and terraforming. Planetary protection is based on the fear...

  2. The Astronomical Pulse of Global Extinction Events

    Directory of Open Access Journals (Sweden)

    David F.V. Lewis

    2006-01-01

    Full Text Available The linkage between astronomical cycles and the periodicity of mass extinctions is reviewed and discussed. In particular, the apparent 26 million year cycle of global extinctions may be related to the motion of the solar system around the galaxy, especially perpendicular to the galactic plane. The potential relevance of Milankovitch cycles is also explored in the light of current evidence for the possible causes of extinction events over a geological timescale.

  3. The Astronomical Code of the Rgveda

    Science.gov (United States)

    Kak, Subhash

    This is the extensively revised edition of the classic book that presented the author's discovery of an astronomical code in the organization of the Rgveda. This code has changed our understanding of the Vedic system of knowledge, rise of earliest astronomy, history of science, and the chronology of ancient India. The work was first reported in a series of journal articles; this book brings together these discoveries between the same two covers for the first time.

  4. A website for astronomical news in Spanish

    Science.gov (United States)

    Ortiz-Gil, A.

    2008-06-01

    Noticias del Cosmos is a collection of web pages within the Astronomical Observatory of the University of Valencia's website where we publish short daily summaries of astronomical press releases. Most, if not all of, the releases are originally written in English, and often Spanish readers may find them difficult to understand because not many people are familiar with the scientific language employed in these releases. Noticias del Cosmos has two principal aims. First, we want to communicate the latest astronomical news on a daily basis to a wide Spanish-speaking public who would otherwise not be able to read them because of the language barrier. Second, daily news can be used as a tool to introduce the astronomical topics of the school curriculum in a more immediate and relevant way. Most of the students at school have not yet reached a good enough level in their knowledge of English to fully understand a press release, and Noticias del Cosmos offers them and their teachers this news in their mother tongue. During the regular programme of school visits at the Observatory we use the news as a means of showing that there is still a lot to be discovered. So far the visits to the website have been growing steadily. Between June 2003 and June 2007 we had more than 30,000 visits (excluding 2006). More than 50% of the visits come from Spain, followed by visitors from South and Central America. The feedback we have received from teachers so far has been very positive, showing the usefulness of news items in the classroom when teaching astronomy.

  5. Preserving Dark Skies: Do Astronomers Care?

    Science.gov (United States)

    Davis, D. R.; Crawford, D. L.

    2001-12-01

    Ground based telescopes are, even in this era of planetary missions and space telescopes, the dominant source of data on solar system objects. Yet many of the premier observing sites in the world are threatened by increasing artificial light that is scattered into the sky - light pollution. World class observing sites such as Mt. Wilson have long since lost the ability to do cutting edge faint object science and observatories in Southern Arizona have been recently threatened - the Canoa Ranch development being the most recent example. Yet there are actions that can be taken to preserve dark skies, not only for astronomy, but also for the benefit of all humanity. Lead by astronomers, effective outdoor lighting codes have been produced and adopted by many jurisdictional authorities. Advocacy organizations such as the International Dark-sky Association (IDA) distribute educational material on how to preserve dark skies through good outdoor lighting practices. Other institutions, such as the National Park Service, are realizing that dark skies are an integral part of the wilderness experience and are taking steps to preserve the quality of their skies. However, the primary beneficaries of dark sky preservation efforts, namely the ground based astronomical community, have largely failed to become involved in efforts to preserve dark skies. For example, only a few percent of the membership of the American Astronomical Society is active in light pollution work or is even a member of IDA. In this presentation, Iwe will outline what is being done locally to preserve dark skies througout the world. In addition, some observations on the level of support from the astronomical community will be offered.

  6. Radio-Astronomical Instruments Observations (Selected Articles),

    Science.gov (United States)

    1982-08-02

    etc. merged into this translation were extracted from the best quality copy available. iii DOC = 82056401 PAGE 1 RADIO-ASTRONOMICAL INSTRUMENTS...itself the series/row of the positive qualities : the possibility of tracking the observed object and the accumulation of signal, the possibility of...L-intoduc ;j~i.a~r DC 82056409 PAGE the installation of quasi-zero mode/conditions this attenuator has remote contril . I’ DOC =82056409 PAGE NA 4 ly

  7. Astronomical random numbers for quantum foundations experiments

    OpenAIRE

    Leung, Calvin; Brown, Amy; Nguyen, Hien; Friedman, Andrew S.; Kaiser, David I.; Gallicchio, Jason

    2017-01-01

    Photons from distant astronomical sources can be used as a classical source of randomness to improve fundamental tests of quantum nonlocality, wave-particle duality, and local realism through Bell's inequality and delayed-choice quantum eraser tests inspired by Wheeler's cosmic-scale Mach-Zehnder interferometer gedankenexperiment. Such sources of random numbers may also be useful for information-theoretic applications such as key distribution for quantum cryptography. Building on the design o...

  8. The la Plata Astronomical Data Center

    Science.gov (United States)

    Marraco, H. G.

    1990-11-01

    RESUMEN. El Centro de Datos Astron6micos tiene su sede en la Facuitad de Ciencias Astron6micas y Geofisicas d la Universidad Nacional de La Plata y funciona por convenio entre esta facultad y el Centre des Stellaires de la Universite' Louis Pasteur en Estrasburgo (CDS), Francia. La finalidad de este centro es la de proveer a los astr6nomos del area con copias de los alrededor de 500 acumulados y/o preparados por el CDS a la vez que promover la producci6n y/o acumulaci6n de en el rea. Para la realizaci6n de esta tarea se cuenta con el apoyo del Centro Superior para el Procesamiento de la Informaci6n (CESPI) de la UNLP cuyos equipos se describen. Las tareas que se estan realizando incluyen la distribuci6n de SIMBAD a los astr6nomos argentinos y se efectuan ensayos de distribuci6n en linea de CD-ROM TEST DISK del Astronomical Data Center (ADC) de la NASA que contiene los 31 mas solicitados por los astr6nomos de todo el mundo. ABSTRACl The La Plata Astronomical Data Center operates by an agreement between the Facultad de Ciencias Astron6micas y Geofisicas at La Plata University and the Centre des Donnees Stellaires of Louis Pasteur University at Strasbourg (CDS), France. The purpose of the Center is to provide to the area astronomers with copies of the catalogs they need amongst those stored and/or prepared at CDS. At the same time the center will act of the astronomical data produced within its area. K words: DATA ANALYSIS

  9. Astronomical Orientations in Sanctuaries of Daunia

    Science.gov (United States)

    Antonello, E.; Polcaro, V. F.; Sisto, A. M. Tunzi; Zupone, M. Lo

    2015-05-01

    Prehistoric sanctuaries of Daunia date back several thousand years. During the Neolithic and Bronze Ages the farmers in that region dug hypogea and holes whose characteristics suggest a ritual use. In the present article we summarize the results of the astronomical analysis of the orientation of the rows of holes in three different sites, and we point out the possible use of the setting of the stars of Centaurus. An interesting archaeological confirmation of an archaeoastronomical prediction is also reported.

  10. Despite Appearances, Cosmic Explosions Have Common Origin, Astronomers Discover

    Science.gov (United States)

    2003-11-01

    A Fourth of July fireworks display features bright explosions that light the sky with different colors, yet all have the same cause. They just put their explosive energy into different colors of light. Similarly, astronomers have discovered, a variety of bright cosmic explosions all have the same origin and the same amount of total energy. This is the conclusion of an international team of astronomers that used the National Science Foundation's Very Large Array (VLA) radio telescope to study the closest known gamma-ray burst earlier this year. Artist's conception of burst Artist's Conception of Twin Jets in Energetic Cosmic Explosion CREDIT: Dana Berry, SkyWorks Digital (Click on Image for Larger Version) "For some reason we don't yet understand, these explosions put greatly varying percentages of their explosive energy into the gamma-ray portion of their output," said Dale Frail, of the National Radio Astronomy Observatory (NRAO) in Socorro, NM. That means, he said, that both strong and weak gamma-ray bursts, along with X-ray flashes, which emit almost no gamma rays, are just different forms of the same cosmic beast. The research team reported their results in the November 13 issue of the scientific journal Nature. The scientists trained the VLA on a gamma-ray burst discovered using NASA's HETE-2 satellite last March 29. This burst, dubbed GRB 030329, was the closest such burst yet seen, about 2.6 billion light-years from Earth. Because of this relative proximity, the burst was bright, with visible light from its explosion reaching a level that could be seen in amateur telescopes. As the burst faded, astronomers noted an underlying distinctive signature of a supernova explosion, confirming that the event was associated with the death of a massive star. Since 1999, astronomers have known that the strong outbursts of gamma rays, X-rays, visible light and radio waves from these bursts form beams, like those from a flashlight, rather than spreading in all directions

  11. GASP-Galway astronomical Stokes polarimeter

    Directory of Open Access Journals (Sweden)

    Shearer A.

    2010-06-01

    Full Text Available The Galway Astronomical Stokes Polarimeter (GASP is an ultra-high-speed, full Stokes, astronomical imaging polarimeter based upon a Division of Amplitude Polarimeter. It has been developed to resolve extremely rapid stochastic (~ms variations in objects such as optical pulsars, magnetars and magnetic cataclysmic variables. The polarimeter has no moving parts or modulated components so the complete Stokes vector can be measured from just one exposure - making it unique to astronomy. The time required for the determination of the full Stokes vector is limited only by detector efficiency and photon fluxes. The polarimeter utilizes a modified Fresnel rhomb that acts as a highly achromatic quarter wave plate and a beamsplitter (referred to as an RBS. We present a description of how the DOAP works, some of the optical design for the polarimeter. Calibration is an important and difficult issue with all polarimeters, but particularly in astronomical polarimeters. We give a description of calibration techniques appropriate to this type of polarimeter.

  12. Astronomical Virtual Observatories Through International Collaboration

    Directory of Open Access Journals (Sweden)

    Masatoshi Ohishi

    2010-03-01

    Full Text Available Astronomical Virtual Observatories (VOs are emerging research environment for astronomy, and 16 countries and a region have funded to develop their VOs based on international standard protocols for interoperability. The 16 funded VO projects have established the International Virtual Observatory Alliance (http://www.ivoa.net/ to develop the standard interoperable interfaces such as registry (meta data, data access, query languages, output format (VOTable, data model, application interface, and so on. The IVOA members have constructed each VO environment through the IVOA interfaces. National Astronomical Observatory of Japan (NAOJ started its VO project (Japanese Virtual Observatory - JVO in 2002, and developed its VO system. We have succeeded to interoperate the latest JVO system with other VOs in the USA and Europe since December 2004. Observed data by the Subaru telescope, satellite data taken by the JAXA/ISAS, etc. are connected to the JVO system. Successful interoperation of the JVO system with other VOs means that astronomers in the world will be able to utilize top-level data obtained by these telescopes from anywhere in the world at anytime. System design of the JVO system, experiences during our development including problems of current standard protocols defined in the IVOA, and proposals to resolve these problems in the near future are described.

  13. AAS Publishing News: Astronomical Software Citation Workshop

    Science.gov (United States)

    Kohler, Susanna

    2015-07-01

    Do you write code for your research? Use astronomical software? Do you wish there were a better way of citing, sharing, archiving, or discovering software for astronomy research? You're not alone! In April 2015, AAS's publishing team joined other leaders in the astronomical software community in a meeting funded by the Sloan Foundation, with the purpose of discussing these issues and potential solutions. In attendance were representatives from academic astronomy, publishing, libraries, for-profit software sharing platforms, telescope facilities, and grantmaking institutions. The goal of the group was to establish “protocols, policies, and platforms for astronomical software citation, sharing, and archiving,” in the hopes of encouraging a set of normalized standards across the field. The AAS is now collaborating with leaders at GitHub to write grant proposals for a project to develop strategies for software discoverability and citation, in astronomy and beyond. If this topic interests you, you can find more details in this document released by the group after the meeting: http://astronomy-software-index.github.io/2015-workshop/ The group hopes to move this project forward with input and support from the broader community. Please share the above document, discuss it on social media using the hashtag #astroware (so that your conversations can be found!), or send private comments to julie.steffen@aas.org.

  14. GalileoMobile: Astronomical activities in schools

    Science.gov (United States)

    Dasi Espuig, Maria; Vasquez, Mayte; Kobel, Philippe

    GalileoMobile is an itinerant science education initiative run on a voluntary basis by an international team of astronomers, educators, and science communicators. Our team's main goal is to make astronomy accessible to schools and communities around the globe that have little or no access to outreach actions. We do this by performing teacher workshops, activities with students, and donating educational material. Since the creation of GalileoMobile in 2008, we have travelled to Chile, Bolivia, Peru, India, and Uganda, and worked with 56 schools in total. Our activities are centred on the GalileoMobile Handbook of Activities that comprises around 20 astronomical activities which we adapted from many different sources, and translated into 4 languages. The experience we gained in Chile, Bolivia, Peru, India, and Uganda taught us that (1) bringing experts from other countries was very stimulating for children as they are naturally curious about other cultures and encourages a collaboration beyond borders; (2) high-school students who were already interested in science were always very eager to interact with real astronomers doing research to ask for career advice; (3) inquiry-based methods are important to make the learning process more effective and we have therefore, re-adapted the activities in our Handbook according to these; (4) local teachers and university students involved in our activities have the potential to carry out follow-up activities, and examples are those from Uganda and India.

  15. SU-F-T-430: Validation of IBEAM Evo Couch Top for Different Relative Electron Density (RED) Combination During Photon Beam Dose Calculation in Monaco− Treatment Planning System

    Energy Technology Data Exchange (ETDEWEB)

    Manigandan, D; Kumar, M; Mohandas, P; Puri, A; Bhalla, N [Fortis Cancer Institute, Mohali, Punjab (India)

    2016-06-15

    Purpose: Validation of iBEAM™ evo couch-top for different relative electron density (RED) combination during photon beam dose calculation in Monaco− TPS. Methods: The iBEAM™ evo couch-top has two layers:outer carbon fiber (CF) and inner foam core (FC). To study the beam intensity attenuation of couch-top, measured doses were compared with doses calculated for different REDs. Measurements were performed in solid water phantom with PTW-0.125cc ion-chamber positioned at center of the phantom with 5.3cm thickness slabs placed above and below the chamber. Similarly, in TPS, iBEAM™ evo couch-top was simulated and doses were calculated for different RED combinations (0.2CF-0.2FC, 0.4CF-0.2FC, 0.6CF-0.2FC, 0.8CF-0.2FC, and 1.0CF-0.2FC) by using Monte Carlo dose calculation algorithm in Monaco TPS (V5.1). Doses were measured for every 10 degree gantry angle separation, 10×10cm{sup 2} field size and 6MV photons. Then, attenuation is defined as the ratio of output at posterior gantry angle to output of its opposed anterior gantry angle (e.g.225°/45°). output fluctuation with different gantry angle was within ±0.21%. To confirm above results, dose-planes were measured for five pelvic VMAT plans (360°arc) in PTW two-dimensional array and compared with different calculated dose-planes of above-mentioned couch REDs. Gamma pass rates<1.00) were analyzed for 3%/2mm criteria. Results: Measured and calculated attenuation was in good agreement for the RED combination of 0.2CF-0.2FC and difference was within ±0.515%. However, other density combination showed difference of ±0.9841%, ±1.667%, ±2.9241% and ±2.8832% for 0.4CF-0.2FC, 0.6CF-0.2FC, 0.8CF-0.2FC, and 1.0CF-0.2FC, respectively. Maximum couch-top attenuation was observed at 110°–120° and 240°–250° and decreases linearly as the gantry angle approaches 180°. Moreover, gamma pass rate confirmed the above results and showed maximum pass rate of 96.23% for 0.2CF-0.2FC, whereas others were 95.72%, 95.12%, 94

  16. The distribution of InCl sub x compounds in model polymeric LEDs A combined low and high-energy ion beam analysis study

    CERN Document Server

    Reijme, M A; Simons, D P L; Schok, M; Ijzendoorn, L J V; Brongersma, H H; De Voigt, M J A

    2002-01-01

    A combination of low- and high-energy ion beam analysis techniques was used to determine the distribution of indium chloride compounds in model polymeric light-emitting diodes (p-LEDs). Parts of polymeric LEDs (polydialkoxyphenylenevinylene (OC sub 1 C sub 1 sub 0 -PPV) on indium-tin-oxide (ITO) substrates) were exposed to a HCl/Ar flow to simulate the processes occurring during conversion of precursor PPVs and acid treatment of polymers. Samples with variable exposure times as well as pristine samples were studied with Rutherford backscattering spectrometry (RBS), low energy ion scattering (LEIS), X-ray photoelectron spectroscopy (XPS) and particle induced X-ray emission (PIXE). The RBS measurements show that after HCl exposure indium is distributed throughout the OC sub 1 C sub 1 sub 0 -PPV layer. LEIS and XPS measurements indicate that the indium and chlorine are present at the outermost surface of the OC sub 1 C sub 1 sub 0 -PPV layer. PIXE measurements in combination with the RBS data demonstrate that th...

  17. Focused ion beam (FIB) combined with high resolution scanning electron microscopy: a promising tool for 3D analysis of chromosome architecture.

    Science.gov (United States)

    Schroeder-Reiter, Elizabeth; Pérez-Willard, Fabián; Zeile, Ulrike; Wanner, Gerhard

    2009-02-01

    Focused ion beam (FIB) milling in combination with field emission scanning electron microscopy (FESEM) was applied to investigations of metaphase barley chromosomes, providing new insight into the chromatin packaging in the chromosome interior and 3D distribution of histone variants in the centromeric region. Whole mount chromosomes were sectioned with FIB with thicknesses in the range of 7-20nm, resulting in up to 2000 sections, which allow high resolution three-dimensional reconstruction. For the first time, it could be shown that the chromosome interior is characterized by a network of interconnected cavities, with openings to the chromosome surface. In combination with immunogold labeling, the centromere-correlated distribution of histone variants (phosphorylated histone H3, CENH3) could be investigated with FIB in three dimensions. Limitations of classical SEM analysis of whole mount chromosomes with back-scattered electrons requiring higher accelerating voltages, e.g. faint and blurred interior signals, could be overcome with FIB milling: from within the chromosome even very small labels in the range of 10nm could be precisely visualized. This allowed direct quantification of marker molecules in a three-dimensional context. Distribution of DNA in the chromosome interior could be directly analyzed after staining with a DNA-specific platinorganic compound Platinum Blue. Higher resolution visualization of DNA distribution could be performed by preparation of FIB lamellae with the in situ lift-out technique followed by investigation in dark field with a scanning transmission electron detector (STEM) at 30kV.

  18. Using radio astronomical receivers for molecular spectroscopic characterization in astrochemical laboratory simulations: A proof of concept

    Science.gov (United States)

    Tanarro, I.; Alemán, B.; de Vicente, P.; Gallego, J. D.; Pardo, J. R.; Santoro, G.; Lauwaet, K.; Tercero, F.; Díaz-Pulido, A.; Moreno, E.; Agúndez, M.; Goicoechea, J. R.; Sobrado, J. M.; López, J. A.; Martínez, L.; Doménech, J. L.; Herrero, V. J.; Hernández, J. M.; Peláez, R. J.; López-Pérez, J. A.; Gómez-González, J.; Alonso, J. L.; Jiménez, E.; Teyssier, D.; Makasheva, K.; Castellanos, M.; Joblin, C.; Martín-Gago, J. A.; Cernicharo, J.

    2018-01-01

    We present a proof of concept on the coupling of radio astronomical receivers and spectrometers with chemical reactors and the performances of the resulting setup for spectroscopy and chemical simulations in laboratory astrophysics. Several experiments including cold plasma generation and UV photochemistry were performed in a 40 cm long gas cell placed in the beam path of the Aries 40 m radio telescope receivers operating in the 41-49 GHz frequency range interfaced with fast Fourier transform spectrometers providing 2 GHz bandwidth and 38 kHz resolution. The impedance matching of the cell windows has been studied using different materials. The choice of the material and its thickness was critical to obtain a sensitivity identical to that of standard radio astronomical observations. Spectroscopic signals arising from very low partial pressures of CH3OH, CH3CH2OH, HCOOH, OCS, CS, SO2 (http://www.aanda.org

  19. Amateur astronomers in support of observing campaigns

    Science.gov (United States)

    Yanamandra-Fisher, P.

    2014-07-01

    The Pro-Am Collaborative Astronomy (PACA) project evolved from the observational campaign of C/2012 S1 or C/ISON. The success of the paradigm shift in scientific research is now implemented in other comet observing campaigns. While PACA identifies a consistent collaborative approach to pro-am collaborations, given the volume of data generated for each campaign, new ways of rapid data analysis, mining access, and storage are needed. Several interesting results emerged from the synergistic inclusion of both social media and amateur astronomers: - the establishment of a network of astronomers and related professionals that can be galvanized into action on short notice to support observing campaigns; - assist in various science investigations pertinent to the campaign; - provide an alert-sounding mechanism should the need arise; - immediate outreach and dissemination of results via our media/blogger members; - provide a forum for discussions between the imagers and modelers to help strategize the observing campaign for maximum benefit. In 2014, two new comet observing campaigns involving pro-am collaborations have been identified: (1) C/2013 A1 (C/Siding Spring) and (2) 67P/Churyumov-Gerasimenko (CG). The evolving need for individual customized observing campaigns has been incorporated into the evolution of PACA (Pro-Am Collaborative Astronomy) portal that currently is focused on comets: from supporting observing campaigns for current comets, legacy data, historical comets; interconnected with social media and a set of shareable documents addressing observational strategies; consistent standards for data; data access, use, and storage, to align with the needs of professional observers. The integration of science, observations by professional and amateur astronomers, and various social media provides a dynamic and evolving collaborative partnership between professional and amateur astronomers. The recent observation of comet 67P, at a magnitude of 21.2, from Siding

  20. Next VLT Instrument Ready for the Astronomers

    Science.gov (United States)

    2000-02-01

    -years away. It is one of the largest known star-forming regions in the Local Group of Galaxies. It was first catalogued as a star, but then recognized to be a nebula by the French astronomer A. Lacaille in 1751-52. The Tarantula Nebula is the only extra-galactic nebula which can be seen with the unaided eye. It contains in the centre the open stellar cluster R 136 with many of the largest, hottest, and most massive stars known. Radio Galaxy Centaurus A ESO Press Photo 05b/00 ESO Press Photo 05b/00 [Preview; JPEG: 400 x 448; 40k] [Normal; JPEG: 800 x 896; 110k] [Full-Res; JPEG: 2048 x 2293; 2.0Mb] The radio galaxy Centarus A , as obtained with FORS2 at KUEYEN during the recent Commissioning period. It was taken during the night of January 31 - February 1, 2000. It is a composite of three exposures in B (300 sec exposure, image quality 0.60 arcsec; here rendered in blue colour), V (240 sec, 0.60 arcsec; green) and R (240 sec, 0.55 arcsec; red). The full-resolution version of this photo retains the orginal pixels. ESO Press Photo 05c/00 ESO Press Photo 05c/00 [Preview; JPEG: 400 x 446; 52k] [Normal; JPEG: 801 x 894; 112k] An area, north-west of the centre of Centaurus A with a detailed view of the dust lane and clusters of luminous blue stars. The normal version of this photo retains the orginal pixels. The new FORS2 image of Centaurus A , also known as NGC 5128 , is an example of how frontier science can be combined with esthetic aspects. This galaxy is a most interesting object for the present attempts to understand active galaxies . It is being investigated by means of observations in all spectral regions, from radio via infrared and optical wavelengths to X- and gamma-rays. It is one of the most extensively studied objects in the southern sky. FORS2 , with its large field-of-view and excellent optical resolution, makes it possible to study the global context of the active region in Centaurus A in great detail. Note for instance the great number of massive and luminous blue

  1. MICRONERVA: A Novel Approach to Large Aperture Astronomical Spectroscopy

    Science.gov (United States)

    Hall, Ryan; Plavchan, Peter; Geneser, Claire; Giddens, Frank; Klenke, Christopher; Weigand, Denise

    2017-01-01

    MICRONERVA (MICRO Novel Exoplanet Radial Velocity Array) is a prototype observatory for measuring spectroscopic radial velocities. The primary goal of MICRONERVA is to demonstrate that an array of 8-inch CPC Celestron telescopes can be used at a lower cost in place of a single, larger telescope. The equivalent light gathering power of the larger telescope is achieved by sending the starlight from each of the eight-inch telescopes down single mode fibers and combining the fiber output at a single entrance slit to a multi-object high resolution spectrograph. All of the hardware from the system is automated using Python programs, ASCOM and MaximDL drivers. The detection of exoplanets using the techniques of MICRONERVA opens the door to reducing costs for astronomical spectroscopy.

  2. Community College Class Devoted to Astronomical Research

    Science.gov (United States)

    Genet, R. M.; Genet, C. L.

    2002-05-01

    A class at a small community college, Central Arizona College, was dedicated to astronomical research. Although hands-on research is usually reserved for professionals or graduate students, and occasionally individual undergraduate seniors, we decided to introduce community college students to science by devoting an entire class to research. Nine students were formed into three closely cooperating teams. The class as a whole decided that all three teams would observe Cepheid stars photometrically using a robotic telescope at the Fairborn Observatory. Speaker-phone conference calls were made to Kenneth E. Kissell for help on Cepheid selection, Michael A. Seeds for instructions on the use of the Phoenix-10 robotic telescope, and Douglas S. Hall for assitance in selecting appropriate comparison and check stars. The students obtained critical references on past observations from Konkoly Observatory via airmail. They spent several long night sessions at our apartment compiling the data, making phase calculations, and creating graphs. Finally, the students wrote up their results for publication in a forthcoming special issue of the international journal on stellar photometry, the IAPPP Communication. We concluded that conducting team research is an excellent way to introduce community college students to science, that a class devoted to cooperation as opposed to competition was refreshing, and that group student conference calls with working astronomers were inspiring. A semester, however, is a rather short time to initiate and complete research projects. The students were Sally Baldwin, Cory Bushnell, Bryan Dehart, Pamela Frantz, Carl Fugate, Mike Grill, Jessica Harger, Klay Lapa, and Diane Wiseman. We are pleased to acknowledge the assistance provided by the astronomers mentioned above, James Stuckey (Campus Dean), and our Union Institute and University doctoral committee members Florence Pittman Matusky, Donald S. Hayes, and Karen S. Grove.

  3. Young Astronomers' Observe with ESO Telescopes

    Science.gov (United States)

    1995-11-01

    Today, forty 16-18 year old students and their teachers are concluding a one-week, educational `working visit' to the ESO Headquarters in Garching (See ESO Press Release 14/95 of 8 November 1995). They are the winners of the Europe-wide contest `Europe Towards the Stars', organised by ESO with the support of the European Union, under the auspices of the Third European Week for Scientific and Technological Culture. From November 14-20, they have worked with professional ESO astronomers in order to get insight into the methods and principles of modern astronomy and astrophysics, as carried out at one of the world's foremost international centres. This included very successful remote observations with the ESO 3.5-m New Technology Telescope (NTT) and the 1.4-m Coude Auxiliary Telescope (CAT) via a satellite link between the ESO Headquarters and the La Silla observatory in Chile, 12,000 kilometres away. After a general introduction to modern astronomy on the first day of the visit, the participants divided into six teams, according to their interests. Some chose to observe distant galaxies, others prefered to have a closer look on binary stars, and one team decided to investigate a star which is thought to be surrounded by a proto-planetary system. Each team was supported by an experienced ESO astronomer. Then followed the observations at the remote consoles during three nights, the first at the NTT and the following at the CAT. Each team had access to the telescope during half a night. Although the work schedule - exactly as in `real' science - was quite hard, especially during the following data reduction and interpretative phase, all teams managed extremely well and in high spirits. The young astronomers' observations were favoured by excellent atmospheric conditions. At the NTT, the seeing was better than 0.5 arcsecond during several hours, an exceptional value that allows very good images to be obtained. All observations represent solid and interesting science, and

  4. The astronomical orientation of ancient Greek temples.

    Science.gov (United States)

    Salt, Alun M

    2009-11-19

    Despite its appearing to be a simple question to answer, there has been no consensus as to whether or not the alignments of ancient Greek temples reflect astronomical intentions. Here I present the results of a survey of archaic and classical Greek temples in Sicily and compare them with temples in Greece. Using a binomial test I show strong evidence that there is a preference for solar orientations. I then speculate that differences in alignment patterns between Sicily and Greece reflect differing pressures in the expression of ethnic identity.

  5. Technology advancements for future astronomical missions

    Science.gov (United States)

    Barnes, Arnold A.; Knight, J. Scott; Lightsey, Paul A.; Harwit, Alex; Coyle, Laura

    2017-09-01

    Future astronomical telescopes in space will have architectures with complex and demanding requirements in order to meet their science goals. The missions currently being studied by NASA for consideration in the next Decadal Survey range in wavelength from the X-ray to Far infrared; examining phenomenon from imaging exoplanets and characterizing their atmospheres to detecting gravitational waves. These missions have technical challenges that are near or beyond the state of the art from the telescope to the detectors. This paper describes some of these challenges and possible solutions. Promising measurements and future demonstrations are discussed that can enhance or enable these missions.

  6. Astronomical Plate Archives and Binary Blazars Studies

    Czech Academy of Sciences Publication Activity Database

    Hudec, René

    2011-01-01

    Roč. 32, 1-2 (2011), s. 91-95 ISSN 0250-6335. [Conference on Multiwavelength Variability of Blazars. Guangzhou, 22,09,2010-24,09,2010] R&D Projects: GA ČR GA205/08/1207 Grant - others:GA ČR(CZ) GA102/09/0997; MŠMT(CZ) ME09027 Institutional research plan: CEZ:AV0Z10030501 Keywords : astronomical plates * plate archives archives * binary blazars Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.400, year: 2011

  7. Weizmann Fast Astronomical Survey Telescope (WFAST)

    Science.gov (United States)

    Nir, Guy; Ofek, Eran Oded; Ben-Ami, Sagi; Manulis, Ilan; Gal-Yam, Avishay; Diner, Oz; Rappaport, Michael

    2017-01-01

    The Weizmann Fast Astronomical Survey Telescope (W-FAST) is an experiment designed to explore variability on sub-second time scales. When completed it will consist of two robotic 55-cm f/2 Schmidt telescopes. The optics is capable of providing $\\sim0.5$" image quality over 23 deg$^2$. The focal plane will be equipped with fast readout, low read-noise sCMOS detectors. The first generation focal plane is expected to have 6.2 deg$^2$ field of view. WFAST is designed to study occultations by solar system objects (KBOs and Oort cloud objects), short time scale stellar variability, and high resolution imaging via proper coaddition.

  8. Le Verrier magnificent and detestable astronomer

    CERN Document Server

    Lequeux, James

    2013-01-01

    Le Verrier was a superb scientist. His discovery of Neptune in 1846 made him the most famous astronomer of his time. He produced a complete theory of the motions of the planets which served as a basis for planetary ephemeris for a full century. Doing this, he discovered an anomaly in the motion of Mercury which later became the first proof of General Relativity. He also founded European meteorology. However his arrogance and bad temper created many enemies, and he was even fired from his position of Director of the Paris Observatory.

  9. Far-infrared spectrophotometer for astronomical observations

    Science.gov (United States)

    Moseley, H.; Silverberg, R. F.

    1981-01-01

    A liquid-helium-cooled far infrared spectrophotometer was built and used to make low resolution observations of the continua of several kinds of astronomical objects using the Kuiper Airborne Observatory. This instrument fills a gap in both sensitivity to continuum sources and spectral resolution between the broadband photometers with lambda/Delta lambda approximately 1 and spectrometers with lambda/Delta lambda greater than 50. While designed primarily to study planetary nebulae, the instrument permits study of the shape of the continua of many weak sources which cannot easily be observed with high resolution systems.

  10. ESO's Studentship Programmes: Training Tomorrow's Astronomers Today

    Science.gov (United States)

    West, Michael; Rejkuba, Marina; Leibundgut, Bruno; Emsellem, Eric

    2009-03-01

    Students are the lifeblood of astronomy, the next generation of astronomers. While other scientific disciplines are facing declining student enrollments, the ASTRONET strategic plan for European Astronomy notes “young students have continued to enter the field at a steady level”. Indeed, with Very Large Telescope (VLT), Atacama Large Millimeter/submillimeter Array (ALMA) the European Extremely Large Telescope (E-ELT) and other exciting new facilities on the horizon, it is hard to imagine a better time to be an astronomy student.

  11. The astronomical revolution Copernicus, Kepler, Borelli

    CERN Document Server

    Koyre, Alexandre

    2013-01-01

    Originally published in English in 1973. This volume traces the development of the revolution which so drastically altered man's view of the universe in the sixteenth and seventeenth centuries. The ""astronomical revolution"" was accomplished in three stages, each linked with the work of one man. With Copernicus, the sun became the centre of the universe. With Kepler, celestial dynamics replaced the kinematics of circles and spheres used by Copernicus. With Borelli the unification of celestial and terrestrial physics was completed by abandonment of the circle in favour the straight line to inf

  12. Astronomical analysis of the taosi observatory site

    Science.gov (United States)

    Liu, C. Y.

    2009-01-01

    An ancient observatory was unearthed recently at Taosi site. This paper discussed the figure of the relic, analyzed the relationship between the 12 backsights and calendar date using astronomical method, and compared the simulated observation with theoretic computation. The investigation shows that backsight E2---E12 indicated the directions of sunrise in the whole year, which were roughly equally distributed and offered an unequal calendar system. The backsight E1 indicated the south-end of the moonrise, giving a time symbol of 18---19 years. This building must be a complex of solar observation, time service, solar worship, and sacrificial ritual

  13. Algorithms for classification of astronomical object spectra

    Science.gov (United States)

    Wasiewicz, P.; Szuppe, J.; Hryniewicz, K.

    2015-09-01

    Obtaining interesting celestial objects from tens of thousands or even millions of recorded optical-ultraviolet spectra depends not only on the data quality but also on the accuracy of spectra decomposition. Additionally rapidly growing data volumes demands higher computing power and/or more efficient algorithms implementations. In this paper we speed up the process of substracting iron transitions and fitting Gaussian functions to emission peaks utilising C++ and OpenCL methods together with the NOSQL database. In this paper we implemented typical astronomical methods of detecting peaks in comparison to our previous hybrid methods implemented with CUDA.

  14. A low-noise HAWAII detector system and new cold optics for the CLASSIC/CLIMB beam combiner instrument of the CHARA array

    Science.gov (United States)

    Beckmann, Udo; Connot, Claus; Heininger, Matthias; Hofmann, Karl-Heinz; Nußbaum, Eddy; Schertl, Dieter; Solscheid, Walter; ten Brummelaar, Theo; Turner, Nils; Weigelt, Gerd

    2014-07-01

    As part of a new collaboration between CHARA and the Max Planck Institute for Radio Astronomy, we have developed a new detector system for the CLASSIC/CLIMB beam combiner of the CHARA Array. This detector is based on the Rockwell HAWAII-1 HgCdTe focal plane array and has lower readout noise (˜5 electrons) than the current PICNIC based system. Presently, CLASSIC/CLIMB observations at different wavelength bands can be made only successively by selecting individual filters in a filter wheel. Therefore, another upgrade goal is to install a non-deviating prism in order to image the H- and K'-band light onto separate detector pixels and to simultaneously observe in the H and K' bands. The detector control electronics were built at the Max Planck Institute for Radio Astronomy. The goal was to achieve the lowest possible readout noise and electronic pick-up noise. The detector readout noise can be significantly reduced by the following approach: First, the analog detector output signal is processed by a moving boxcar filter consisting of an analog approximation of a finite impulse response filter with a response time adapted to the 10 MHz sample rate of an analog-to-digital converter. Second, a digital filter averages up to 1024 samples for each addressed pixel. This hybrid (analog plus digital) filter approach gives a unique flexibility of a programmable bandwidth for optimum noise reduction.

  15. Improvement of Galilean refractive beam shaping system for accurately generating near-diffraction-limited flattop beam with arbitrary beam size.

    Science.gov (United States)

    Ma, Haotong; Liu, Zejin; Jiang, Pengzhi; Xu, Xiaojun; Du, Shaojun

    2011-07-04

    We propose and demonstrate the improvement of conventional Galilean refractive beam shaping system for accurately generating near-diffraction-limited flattop beam with arbitrary beam size. Based on the detailed study of the refractive beam shaping system, we found that the conventional Galilean beam shaper can only work well for the magnifying beam shaping. Taking the transformation of input beam with Gaussian irradiance distribution into target beam with high order Fermi-Dirac flattop profile as an example, the shaper can only work well at the condition that the size of input and target beam meets R(0) ≥ 1.3 w(0). For the improvement, the shaper is regarded as the combination of magnifying and demagnifying beam shaping system. The surface and phase distributions of the improved Galilean beam shaping system are derived based on Geometric and Fourier Optics. By using the improved Galilean beam shaper, the accurate transformation of input beam with Gaussian irradiance distribution into target beam with flattop irradiance distribution is realized. The irradiance distribution of the output beam is coincident with that of the target beam and the corresponding phase distribution is maintained. The propagation performance of the output beam is greatly improved. Studies of the influences of beam size and beam order on the improved Galilean beam shaping system show that restriction of beam size has been greatly reduced. This improvement can also be used to redistribute the input beam with complicated irradiance distribution into output beam with complicated irradiance distribution.

  16. The FLUOR interferometric beam combiner

    Science.gov (United States)

    Coudé du Foresto, Vincent; Chagnon, Gilles; Lacasse, Marc; Mennesson, Bertrand; Morel, Sébastien; Perrin, Guy; Ridgway, Steve; Traub, Wesley

    2001-01-01

    FLUOR stands for Fibered Linked Unit for Optical Recombination and is an interferometric instrument which started out as a technology demonstrator, demonstrated the potential of single-mode fiber optics for high precision visibility measurements, and has been operated as a focal instrument of the IOTA interferometer since 1995. After a presentation of the instrument, the programs carried out with FLUOR are reviewed, as well as the perspectives introduced by interferometric observations with a high dynamic range.

  17. Detection and Implications of Laser-Induced Raman Scattering at Astronomical Observatories

    Directory of Open Access Journals (Sweden)

    Frédéric P. A. Vogt

    2017-06-01

    Full Text Available Laser guide stars employed at astronomical observatories provide artificial wavefront reference sources to help correct (in part the impact of atmospheric turbulence on astrophysical observations. Following the recent commissioning of the 4 Laser Guide Star Facility (4LGSF on Unit Telescope 4 (UT4 of the Very Large Telescope (VLT, we characterize the spectral signature of the uplink beams from the 22-W lasers to assess the impact of laser scattering from the 4LGSF on science observations. We use the Multi-Unit Spectroscopic Explorer (MUSE optical integral field spectrograph mounted on the Nasmyth B focus of UT4 to acquire spectra at a resolution of R≅3000 of the uplink laser beams over the wavelength range of 4750 Å–9350 Å. We report the first detection of laser-induced Raman scattering by N_{2}, O_{2}, CO_{2}, H_{2}O, and (tentatively CH_{4} molecules in the atmosphere above the astronomical observatory of Cerro Paranal. In particular, our observations reveal the characteristic spectral signature of laser photons—but 480 Å to 2210 Å redder than the original laser wavelength of 5889.959 Å—landing on the 8.2-m primary mirror of UT4 after being Raman-scattered on their way up to the sodium layer. Laser-induced Raman scattering, a phenomenon not usually discussed in the astronomical context, is not unique to the observatory of Cerro Paranal, but it is common to any astronomical telescope employing a laser guide star (LGS system. It is thus essential for any optical spectrograph coupled to a LGS system to thoroughly handle the possibility of a Raman spectral contamination via a proper baffling of the instrument and suitable calibrations procedures. These considerations are particularly applicable for the HARMONI optical spectrograph on the upcoming Extremely Large Telescope (ELT. At sites hosting multiple telescopes, laser-collision-prediction tools should also account for the presence of Raman emission from the uplink laser beam(s

  18. Detection and Implications of Laser-Induced Raman Scattering at Astronomical Observatories

    Science.gov (United States)

    Vogt, Frédéric P. A.; Bonaccini Calia, Domenico; Hackenberg, Wolfgang; Opitom, Cyrielle; Comin, Mauro; Schmidtobreik, Linda; Smoker, Jonathan; Blanchard, Israel; Espinoza Contreras, Marcela; Aranda, Ivan; Milli, Julien; Jaffe, Yara L.; Selman, Fernando; Kolb, Johann; Hibon, Pascale; Kuntschner, Harald; Madec, Pierre-Yves

    2017-04-01

    Laser guide stars employed at astronomical observatories provide artificial wavefront reference sources to help correct (in part) the impact of atmospheric turbulence on astrophysical observations. Following the recent commissioning of the 4 Laser Guide Star Facility (4LGSF) on Unit Telescope 4 (UT4) of the Very Large Telescope (VLT), we characterize the spectral signature of the uplink beams from the 22-W lasers to assess the impact of laser scattering from the 4LGSF on science observations. We use the Multi-Unit Spectroscopic Explorer (MUSE) optical integral field spectrograph mounted on the Nasmyth B focus of UT4 to acquire spectra at a resolution of R ≅3000 of the uplink laser beams over the wavelength range of 4750 Å-9350 Å. We report the first detection of laser-induced Raman scattering by N2 , O2 , CO2 , H2O , and (tentatively) CH4 molecules in the atmosphere above the astronomical observatory of Cerro Paranal. In particular, our observations reveal the characteristic spectral signature of laser photons—but 480 Å to 2210 Å redder than the original laser wavelength of 5889.959 Å—landing on the 8.2-m primary mirror of UT4 after being Raman-scattered on their way up to the sodium layer. Laser-induced Raman scattering, a phenomenon not usually discussed in the astronomical context, is not unique to the observatory of Cerro Paranal, but it is common to any astronomical telescope employing a laser guide star (LGS) system. It is thus essential for any optical spectrograph coupled to a LGS system to thoroughly handle the possibility of a Raman spectral contamination via a proper baffling of the instrument and suitable calibrations procedures. These considerations are particularly applicable for the HARMONI optical spectrograph on the upcoming Extremely Large Telescope (ELT). At sites hosting multiple telescopes, laser-collision-prediction tools should also account for the presence of Raman emission from the uplink laser beam(s) to avoid the unintentional

  19. Astronomical Alignments in a Neolithic Chinese Site?

    Science.gov (United States)

    Nelson, S.; Stencel, R. E.

    1997-12-01

    In the Manchurian province of Liaoning, near 41N19' and 119E30', exist ruins of a middle Neolithic society (2500 to 4000 BC) known as the Hongshan culture. This location, called Niuheliang, is comprised of 16 locations with monumental structures scattered over 80 square kilometers of hills. Most are stone burial structures that contain jade artifacts implying wealth and power. One structure is unique in being unusually shaped and containing oversized effigies of goddess figures. This structure also has a commanding view of the surrounding landscape. The presence of decorated pottery, jade and worked copper suggests the Hongshan people were sophisticated artisans and engaged in long-distance trading. During 1997, we've conducted a course at Denver as part of our Core Curriculum program for upper division students, that has examined the astronomical and cultural aspects of the Niuheliang site, to attempt to determine whether these contemporaries of the builders of Stonehenge may have included astronomical alignments into their constructions. The preliminary result of our studies suggests that certain monuments have potential for lunar standstill observation from the "goddess temple". For updates on these results, please see our website: www.du.edu/ rstencel/core2103.html.

  20. Astronomers Discover Spectacular Structure in Distant Galaxy

    Science.gov (United States)

    1999-01-01

    Researchers using the National Science Foundation's Very Large Array (VLA) radio telescope have imaged a "spectacular and complex structure" in a galaxy 50 million light-years away. Their work both resolves a decades-old observational mystery and revises current theories about the origin of X-ray emission coming from gas surrounding the galaxy. The new VLA image is of the galaxy M87, which harbors at its core a supermassive black hole spewing out jets of subatomic particles at nearly the speed of light and also is the central galaxy of the Virgo Cluster of galaxies. The VLA image is the first to show detail of a larger structure that originally was detected by radio astronomers more than a half-century ago. Analysis of the new image indicates that astronomers will have to revise their ideas about the physics of what causes X-ray emission in the cores of many galaxy clusters. Frazer Owen of the National Radio Astronomy Observatory (NRAO) in Socorro, NM; Jean Eilek of the New Mexico Institute of Mining and Technology (NM Tech) in Socorro, NM; and Namir Kassim of the Naval Research Laboratory in Washington, DC, announced their discovery at the American Astronomical Society's meeting today in Austin, TX. The new observations show two large, bubble-like lobes, more than 200,000 light-years across, that emit radio waves. These lobes, which are intricately detailed, apparently are powered by gravitational energy released from the black hole at the galaxy's center. "We think that material is flowing outward from the galaxy's core into these large, bright, radio-emitting 'bubbles,'" Owen said. The newly-discovered "bubbles" sit inside a region of the galaxy known to be emitting X-rays. Theorists have speculated that this X-ray emission arises when gas that originally was part of the Virgo Cluster of galaxies, cools and falls inwards onto M87 itself, at the center of the cluster. Such "cooling flows" are commonly thought to be responsible for strong X-ray emission in many

  1. Young Astronomers and Astronomy teaching in Moldavia

    Science.gov (United States)

    Gaina, Alex

    1998-09-01

    Curricular Astronomy is taught in Moldavia , except Transnistria and Gagauzia, in the final (11th class) of the secondary schools and gymnasiums, and in the 12th class of the lyceums. The program takes 35 academic hours. The basic book is by Vorontsov-Veliaminov, used in the former USSR, but the Romanian one is also used, in spite of many criticisms addressed to both by our astronomy teachers. In Transinstria (on the left of the Dniester river)astronomy is taught 17 hours. Extracurricular activities develop at the Real Lyceum, where students and amateur astronomers carry out regular observations. Particularly, photographs of the comet Hale-Bopp have been realized using a Cassegrain 450 mm telescope by young astronomers under supervision of S. Luca and D. Gorodetzky (Gorodetchi). Except the telescope from the Real Lyceum other few telescopes are in construction. Unfortunately, no planetarium exists now in Chisinau, since the old one was returned to church. Astronomy courses are taught at the physical and mathematical departments of the Pedagogical University, Transnistrian Moldavian University in Tiraspol and the State University of |Moldavia. Many efforts were made by the State University lecturers and scientists to popularize Astronomy and Astrophysics in the books and in the press, at the radio and TV. No astronomy is taught at the Gagauzian National University in Comrat. No astronomiucal departments exist in Universities of |Moldavia.

  2. Sketching the moon an astronomical artist's guide

    CERN Document Server

    Handy, Richard; McCague, Thomas; Rix, Erika; Russell, Sally

    2012-01-01

    Soon after you begin studying the sky through your small telescope or binoculars, you will probably be encouraged by others to make sketches of what you see. Sketching is a time-honored tradition in amateur astronomy and dates back to the earliest times, when telescopes were invented. Even though we have lots of new imaging technologies nowadays, including astrophotography, most observers still use sketching to keep a record of what they see, make them better observers, and in hopes of perhaps contributing something to the body of scientific knowledge about the Moon. Some even sketch because it satisfies their artistic side. The Moon presents some unique challenges to the astronomer-artist, the Moon being so fond of tricks of the light. Sketching the Moon: An Astronomical Artist’s Guide, by five of the best lunar observer-artists working today, will guide you along your way and help you to achieve really high-quality sketches. All the major types of lunar features are covered, with a variety of sketching te...

  3. Harvey Butcher: a passion for astronomical instrumentation

    Science.gov (United States)

    Bhathal, Ragbir

    2014-11-01

    This paper covers some aspects of the scientific life of Harvey Butcher who was the Director of the Research School for Astronomy and Astrophysics at the Australian National University in Canberra from September 2007 to January 2013. He has made significant contributions to research on the evolution of galaxies, nucleosynthesis, and on the design and implementation of advanced astronomical instrumentation including LOFAR (Low Frequency Array Radio telescope). He is well known for his discovery of the Butcher-Oemler effect. Before coming to Australia he was the Director of the Netherlands Foundation for Research in Astronomy from September 1991 to January 2007. In 2005 he was awarded a Knighthood in the Order of the Netherlands Lion for contributions to interdisciplinary science, innovation and public outreach.This paper is based on an interview conducted by the author with Harvey Butcher for the National Project on Significant Australian Astronomers sponsored by the National Library of Australia. Except otherwise stated, all quotations used in this paper are from the Butcher interview which has been deposited in the Oral History Archives of the National Library.

  4. Powerful Radio Burst Indicates New Astronomical Phenomenon

    Science.gov (United States)

    2007-09-01

    Astronomers studying archival data from an Australian radio telescope have discovered a powerful, short-lived burst of radio waves that they say indicates an entirely new type of astronomical phenomenon. Region of Strong Radio Burst Visible-light (negative greyscale) and radio (contours) image of Small Magellanic Cloud and area where burst originated. CREDIT: Lorimer et al., NRAO/AUI/NSF Click on image for high-resolution file ( 114 KB) "This burst appears to have originated from the distant Universe and may have been produced by an exotic event such as the collision of two neutron stars or the death throes of an evaporating black hole," said Duncan Lorimer, Assistant Professor of Physics at West Virginia University (WVU) and the National Radio Astronomy Observatory (NRAO). The research team led by Lorimer consists of Matthew Bailes of Swinburne University in Australia, Maura McLaughlin of WVU and NRAO, David Narkevic of WVU, and Fronefield Crawford of Franklin and Marshall College in Lancaster, Pennsylvania. The astronomers announced their findings in the September 27 issue of the online journal Science Express. The startling discovery came as WVU undergraduate student David Narkevic re-analyzed data from observations of the Small Magellanic Cloud made by the 210-foot Parkes radio telescope in Australia. The data came from a survey of the Magellanic Clouds that included 480 hours of observations. "This survey had sought to discover new pulsars, and the data already had been searched for the type of pulsating signals they produce," Lorimer said. "We re-examined the data, looking for bursts that, unlike the usual ones from pulsars, are not periodic," he added. The survey had covered the Magellanic Clouds, a pair of small galaxies in orbit around our own Milky Way Galaxy. Some 200,000 light-years from Earth, the Magellanic Clouds are prominent features in the Southern sky. Ironically, the new discovery is not part of these galaxies, but rather is much more distant

  5. Heavens Open Up for UK Astronomers

    Science.gov (United States)

    2002-07-01

    A significant milestone for British and European science occurred today (July 8, 2002) when the Council of the European Southern Observatory (ESO) met in London. At this historical meeting, the United Kingdom was formally welcomed into ESO by the nine other member states. The UK, one of the leading nations in astronomical research, now joins one of the world's major astronomical organisations. UK astronomers will now be able to use the four 8.2-metre and several 1.8-metre telescopes that comprise the Very Large Telescope (VLT) facility located at the Paranal Observatory in the northern part of the Atacama desert in Chile, as well as two 4-m class telescopes and several smaller ones at the ESO La Silla Observatory further south. The UK will also benefit from increased involvement in the design and construction of the Atacama Large Millimetre Array (ALMA), a network of 64 twelve-metre telescopes also sited in Chile, and play a defining role in ESO's 100-metre Overwhelmingly Large Telescope (OWL). Sir Martin Rees , The Astronomer Royal, said, "Joining ESO is good for UK science, and I think good for Europe as well. It offers us access to the VLT's 8-m class telescopes and restores the UK's full competitiveness in optical astronomy. We're now guaranteed full involvement in ALMA and in the next generation of giant optical instruments - projects that will be at the forefront of the research in the next decade and beyond. Moreover, our commitment to ESO should enhance its chances of forging ahead of the US in these technically challenging and high profile scientific projects. UK membership of ESO is a significant and welcome outcome of this government's increasing investment in science". Prof. Ian Halliday , Chief Executive of the Particle Physics and Astronomy Research Council (PPARC), the UK's strategic science investment agency said, "The United Kingdom already participates in Europe's flagship particle physics research and the space science research programmes through

  6. The First Astronomical Observatory in Cluj-Napoca

    Science.gov (United States)

    Szenkovits, Ferenc

    2008-09-01

    One of the most important cities of Romania is Cluj-Napoca (Kolozsvár, Klausenburg). This is a traditional center of education, with many universities and high schools. From the second half of the 18th century the University of Cluj has its own Astronomical Observatory, serving for didactical activities and scientific researches. The famous astronomer Maximillian Hell was one of those Jesuits who put the base of this Astronomical Observatory. Our purpose is to offer a short history of the beginnings of this Astronomical Observatory.

  7. Grid-Enabled Interactive Data Language for Astronomical Data Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Grid technologies provide a valuable solution for data intensive scientific applications but are not readily available for astronomical data and Interactive Data...

  8. Astronomers Make First Images With Space Radio Telescope

    Science.gov (United States)

    1997-07-01

    Marking an important new milestone in radio astronomy history, scientists at the National Radio Astronomy Observatory (NRAO) in Socorro, New Mexico, have made the first images using a radio telescope antenna in space. The images, more than a million times more detailed than those produced by the human eye, used the new Japanese HALCA satellite, working in conjunction with the National Science Foundation's (NSF) Very Long Baseline Array (VLBA) and Very Large Array (VLA) ground-based radio telescopes. The landmark images are the result of a long-term NRAO effort supported by the National Aeronautics and Space Administration (NASA). "This success means that our ability to make detailed radio images of objects in the universe is no longer limited by the size of the Earth," said NRAO Director Paul Vanden Bout. "Astronomy's vision has just become much sharper." HALCA, launched on Feb. 11 by Japan's Institute of Space and Astronautical Science (ISAS), is the first satellite designed for radio astronomy imaging. It is part of an international collaboration led by ISAS and backed by NRAO; Japan's National Astronomical Observatory; NASA's Jet Propulsion Laboratory (JPL); the Canadian Space Agency; the Australia Telescope National Facility; the European VLBI Network and the Joint Institute for Very Long Baseline Interferometry in Europe. On May 22, HALCA observed a distant active galaxy called PKS 1519-273, while the VLBA and VLA also observed it. Data from the satellite was received by a tracking station at the NRAO facility in Green Bank, West Virginia. Tape-recorded data from the satellite and from the radio telescopes on the ground were sent to NRAO's Array Operations Center (AOC) in Socorro, NM. In Socorro, astronomers and computer scientists used a special-purpose computer to digitally combine the signals from the satellite and the ground telescopes to make them all work together as a single, giant radio telescope. This dedicated machine, the VLBA Correlator, built as

  9. 16 years of airglow measurement with astronomical facilities

    Science.gov (United States)

    Kausch, Wolfgang; Noll, Stefan; Kimeswenger, Stefan; Unterguggenberger, Stefanie; Jones, Amy; Proxauf, Bastian

    2017-04-01

    Observations taken with ground-based astronomical telescopes are affected by various airglow emission processes in the Earth's upper atmosphere. This chemiluminescent emission can be used to investigate the physical state of the meso- and the thermosphere. By applying a modified approach of techniques originally developed to characterise and remove these features from the astronomical spectra, which are not primarily taken for airglow studies, these spectra are suitable for airglow research. For our studies, we currently use data from two observing sites on both hemispheres for our studies: The European Southern Observatory operates four 8m telescopes at the Very Large Telescope (VLT) in the Chilean Atacama desert (24.6°S, 70.4°W). The 2.5m Sloan Digital Sky Survey telescope (SDSS) located in New Mexico/USA (32.8°N, 105.8°W) provides observations from the northern hemisphere. Each of these telescopes is equipped with several astronomical instruments. Among them are several spectrographs operating in the optical and near-IR regime with medium to high spectral resolution. Currently, we work on data from the following three spectrographs (1) UVES@VLT (Ultraviolet and Visual Echelle Spectrograph): This instrument provides spectra in the wavelength regime from 0.3 to 1.1μm in small spectral ranges. Its high resolving power (up to R˜110 000) allows a detailed study of oxygen (OI@557nm, OI@630nm), sodium (NaD@589nm), nitrogen (NI@520nm), and many OH bands. UVES has been in operation since 1999 providing the longest time series. (2) X-Shooter@VLT: This spectrograph is unique as it provides the whole wavelength range from 0.3 to 2.5μm at once with medium resolving power (R˜3 300 to 18 000, depending on the setup). This enables us to study the dependency of optical and near-IR airglow processes simultaneously, e.g. the OH bands. In addition, weak airglow continuum emission, e.g. arising from FeO and NiO can be studied. In operation since 2009, the data cover half a

  10. Digital Image Processing Techniques to Create Attractive Astronomical Images from Research Data

    Science.gov (United States)

    Rector, T. A.; Levay, Z.; Frattare, L.; English, J.; Pu'uohau-Pummill, K.

    2004-05-01

    The quality of modern astronomical data, the power of modern computers and the agility of current image processing software enable the creation of high-quality images in a purely digital form that rival the quality of traditional photographic astronomical images. The combination of these technological advancements has created a new ability to make color astronomical images. And in many ways, it has led to a new philosophy towards how to create them. We present a practical guide to generate astronomical images from research data by using powerful image processing programs. These programs use a layering metaphor that allows an unlimited number of astronomical datasets to be combined in any desired color scheme, creating an immense parameter space to be explored using an iterative approach. Several examples of image creation are presented. We also present a philosophy on how to use color and composition to create images that simultaneously highlight the scientific detail within an image and are aesthetically appealing. We advocate an approach that uses visual grammar, defined as the elements which affect the interpretation of an image, to maximize the richness and detail in an image while maintaining scientific accuracy. By properly using visual grammar, one can imply qualities that a two-dimensional image intrinsically cannot show, such as depth, motion and energy. In addition, composition can be used to engage the viewer and keep him or her interested for a longer period of time. The effective use of these techniques can result in a striking image that will effectively convey the science within the image, to scientists and to the public.

  11. A New Bibliographical Feature for SIMBAD: Highlighting the Most Relevant Papers for One Astronomical Object

    Science.gov (United States)

    Oberto, A.; Lesteven, S.; Derriere, S.; Bonnin, C.; Buga, M.; Brouty, M.; Bruneau, C.; Brunet, C.; Eisele, A.; Genova, F.; Guéhenneux, S.; Neuville, M.; Ochsenbein, F.; Perret, E.; Son, E.; Vannier, P.; Vonflie, P.; Wenger, M.; Woelfel, F.

    2015-04-01

    The number of bibliographical references attached to an astronomical object in SIMBAD is has been growing continuously over the years. It is important for astronomers to retrieve the most relevant papers, those that give important information about the object of study. This is not easy since there can be many references attached to one object. For instance, in 2014, more than 15,000 objects had been attached to more than 50 references. The location of the object's citations inside the paper and its number of occurrences are important criteria to extract the most relevant papers. Since 2008, because of the DJIN application (a semi-automatic tool to search for object names in full text) this information has been collected. For each article associated with an astronomical object, we know where it is cited and how many times and with which name it appears. Since September 2013, the users of SIMBAD web site can choose to retrieve the most relevant references for an astronomical object depending on its location in the publication. A new formula to sort references by combining all locations, number of occurrences, total number of objects studied, citation count, and year is presented in this paper.

  12. Multinational History of Strasbourg Astronomical Observatory

    CERN Document Server

    Heck, André

    2005-01-01

    Strasbourg Astronomical Observatory is quite an interesting place for historians: several changes of nationality between France and Germany, high-profile scientists having been based there, big projects born or installed in its walls, and so on. Most of the documents circulating on the history of the Observatory and on related matters have however been so far poorly referenced, if at all. This made necessary the compilation of a volume such as this one, offering fully-documented historical facts and references on the first decades of the Observatory history, authored by both French and German specialists. The experts contributing to this book have done their best to write in a way understandable to readers not necessarily hyperspecialized in astronomy nor in the details of European history. After an introductory chapter by the Editor, contributions by Wolfschmidt and by Duerbeck respectively deal extensively with the German periods and review people and instrumentation, while another paper by Duerbeck is more...

  13. Young astronomer in Denmark 1946 to 1958

    CERN Document Server

    Høg, Erik

    2015-01-01

    This is a personal account of how I became an astronomer. Fascinated by the stars and planets in the dark sky over Lolland, an island 100 km south of Copenhagen, the interest in astronomy was growing. Encouraged by my teachers, I polished mirrors and built telescopes with generous help from the local blacksmith and I observed light curves of variable stars. Studies at the Copenhagen University from 1950 gradually led me deeper into astronomy, especially astrometry (the astronomy of positions), guided by professor Bengt Str\\"omgren and my mentor dr. phil. Peter Naur. I was lucky to take part in the buildup of the new observatory at Brorfelde during the first difficult years and the ideas I gathered there have contributed to the two astrometry satellites Hipparcos and Gaia launched by the European Space Agency (ESA) in respectively 1989 and 2013.

  14. Astronomical knowledge transmission through illustrated Aratea manuscripts

    CERN Document Server

    Dolan, Marion

    2017-01-01

    This carefully researched monograph is a historical investigation of the illustrated Aratea astronomical manuscript and its many interpretations over the centuries. Aratus' 270 B.C.E. Greek poem describing the constellations and astrological phenomena was translated and copied over 800 years into illuminated manuscripts that preserved and illustrated these ancient stories about the constellations. The Aratea survives in its entirety due to multiple translations from Greek to Latin and even to Arabic, with many illuminated versions being commissioned over the ages. The survey encompasses four interrelated disciplines: history of literature, history of myth, history of science, and history of art. Aratea manuscripts by their nature are a meeting place of these distinct branches, and the culling of information from historical literature and from the manuscripts themselves focuses on a wider, holistic view; a narrow approach could not provide a proper prospective. What is most essential to know about this work is...

  15. Shirakatsi Astronomical and Natural Philosophical Views

    Science.gov (United States)

    Mkrtchyan, Lilit

    2016-12-01

    Our work is aimed at presenting Shirakatsi astronomical and natural philosophical views. Karl Anania Shirakatsi is classified as one of the world-class intellectual geniuses. He was endowed with exceptional talent and analyzing scientific understanding of natural phenomena. He refers his philosophical works to almost all fields of science, cosmography, mathematics, calendarology, historiography, etc. Shirakatsy's earnings of natural science and natural philosophy in medieval is too big He was the first prominent scholar and thinker of his time, creating a unique, comprehensive gitapilisopayakan system that still feeds the human mind. The scientific value of Shirakatsi has great importance not only for Armenians but also for the whole world of science, history, culture and philosophy. Shirakatsi can be considered not only national but also universal greatness.

  16. Dacic Ancient Astronomical Research in Sarmizegetuza

    Directory of Open Access Journals (Sweden)

    Emanuel George Oprea

    2015-11-01

    Full Text Available The actual Romanian territory belongs to Carpatho-Danubian Space and to Ancient Europe. The Ancient European Society was a vast cultural entity based on a theocratic, matriarchal society, peaceful and art creating.Temples of Sarmizegetusa have given rise to several theories over time, proven by historians with the most diverse arguments. The largest complex of temples and sanctuaries was founded in Sarmizegetusa Regia, the Dacian’s main fortress and ancient capital of Dacia in the time of King Decebalus. The mysterious form of settlements has led researchers to the conclusion that the locations were astronomical observation shrines. Among the places of Dacian worship in Orastie Mountains the most impressive is the Great Circular Sanctuary, used to perform some celestial observations, and also as original solar calendar. This paper had the purpose to re-discover the Dacian Civilization and Dacian cosmogony based on the accumulated knowledge upon our country’s past.

  17. A Star Formation/ISM Astronomical Database

    Science.gov (United States)

    Molinari, Sergio; Ali, Babar; Good, John; Noriega-Crespo, Alberto

    2003-02-01

    The Star Formation/ISM Astronomical Database (hereafter SFD) will be a set of on-line services adding value to existing data archives and published journals, along the lines of the very successful NASA/IPAC Extragalactic Database (NED) and SIMBAD projects but with a focus on star formation an the interstellar medium (ISM) within the Milky Way. Unlike NED and SIMBAD, however, the SFD must deal with multi-wavelength measurements of extended regions and cross-correlative relationships between disparate measurements. The SFD will rely heavily on existing databases, primarily adding data content and connectivity between datasets around the world, and custom tailoring of existing tools to provide interfaces (programming API, Web, and JAVA GUI) specific to this application. We consider the SFD as a valuable component in the broader context of a future Virtual Observatory.

  18. A possible Harappan Astronomical Observatory at Dholavira

    CERN Document Server

    Vahia, Mayank N

    2013-01-01

    Astronomy arises very early in a civilization and evolves as the civilization advances. It is therefore reasonable to assume that a vibrant knowledge of astronomy would have been a feature of a civilization the size of the Harappan Civilization. We suggest that structures dedicated to astronomy existed in every major Harappan city. One such city was Dholavira, an important trading port that was located on an island in what is now the Rann of Kutch during the peak of the Harappan Civilization. We have analyzed an unusual structure at Dholavira that includes two circular rooms. Upon assuming strategically-placed holes in their ceilings we examine the internal movement of sunlight within these rooms and suggest that the larger structure of which they formed a part could have functioned as an astronomical observatory.

  19. Preparing Colorful Astronomical Images III: Cosmetic Cleaning

    Science.gov (United States)

    Frattare, L. M.; Levay, Z. G.

    2003-12-01

    We present cosmetic cleaning techniques for use with mainstream graphics software (Adobe Photoshop) to produce presentation-quality images and illustrations from astronomical data. These techniques have been used on numerous images from the Hubble Space Telescope when producing photographic, print and web-based products for news, education and public presentation as well as illustrations for technical publication. We expand on a previous paper to discuss the treatment of various detector-attributed artifacts such as cosmic rays, chip seams, gaps, optical ghosts, diffraction spikes and the like. While Photoshop is not intended for quantitative analysis of full dynamic range data (as are IRAF or IDL, for example), we have had much success applying Photoshop's numerous, versatile tools to final presentation images. Other pixel-to-pixel applications such as filter smoothing and global noise reduction will be discussed.

  20. Thirty years of astronomical discovery with UKIRT

    CERN Document Server

    Davies, John; Robson, Ian; The Scientific Achievement of the United Kingdom InfraRed Telescope

    2013-01-01

    These are the proceedings of an international meeting hosted by the Royal Observatory, Edinburgh, to commemorate the 30th anniversary of the dedication of the UKIRT, the United Kingdom InfraRed Telescope. The volume comprises 31 professional level papers. The first part of the book has 10 thorough reviews of the conception, design and build of the telescope, as well as accounts of some its key instruments such as IRCAM (the common-user infrared camera), CGS4 (the fourth Cooled Grating Spectrometer) and the Wide Field Camera. The second part of the book comprises 14 reviews of scientific achievements during its twenty years of visitor mode operations. The final part of the book is a series of 7 reviews of the results from the multiple surveys being done as part of UKIDSS (UKIRT Infrared Deep Sky Survey). The authors are all experts in their respective fields, for example instrument scientists, operations staff and leading astronomers.

  1. Polarization in astronomical spectra - Theoretical evidence

    Science.gov (United States)

    Fymat, A. L.

    1974-01-01

    Theoretical evidence for the existence and behavior of polarization in astronomical spectra is provided. The theory for the study of spectral multiple scattering of arbitrarily polarized light is first developed, and the detailed and integrated spectropolarimetry of a planetary atmosphere is then studied for cases in which the spectra are formed in the presence of either very small nonspherical particles (Rayleigh-Cabannes scattering) or large polydisperse spherical particles (Mie scattering). It is shown in both cases that polarization is indeed present; it increases with the line strength but decreases afterwards as the line becomes very strong and tends to saturation. A polarization reversal is also predicted during latitudinal (pole-to-equator) scan and possibly also during longitudinal (terminator-to-limb) scan of the planet. The reversal happened at all phase angles considered. Our companion article (Forbes and Fymat) will provide observational substantiation to these theoretical predictions.

  2. Integral Programme of Basic Astronomic Literacy Development

    Science.gov (United States)

    Tignanelli, H.

    2009-05-01

    We discuss the development and optimization of an ongoing educational project involving the whole population of the province of San Luis, Argentina. The core of the project includes activities and resources that capture formal curricular aspects directed towards all levels of teaching. The educational activities related to this project have been benefited by the acquisition of two planetariums made in Argentina, a MEADE 16'' telescope to be operated by remote control from any school-room in San Luis, and a naked-eye observatory with more than 30 pre-telescopic instruments, and other didactic tools specially designed for the teaching of Astronomy. Furthermore, an Internet site to upload all the astronomical activities suggested that has been developed along with a number of didactic and general-interest publications.

  3. The astronomical revolution. Copernicus - Kepler - Borelli.

    Science.gov (United States)

    Koyré, A.

    The work was originally published in 1961 under the title "La révolution astronomique" as part of the series, Histoire de la pensée. This book is an unabridged and unaltered republication of the English translation, by R. E. W. Maddison, originally published in 1973 (see 10.003.074). The author elucidates, precisely and in stages, the revolutionary ideas of Nicolaus Copernicus as well as the work of two other thinkers who made major contributions to the astronomical revolution: Johannes Kepler and Giovanni Borelli. He illuminates the exact contribution of each man, placing his work in its historical context and dispelling a host of misconceptions about it. In order to effectively recapture the ferment and flavor of the times, the author, whenever possible, has allowed Copernicus, Kepler and Borelli to speak for themselves by quoting key passages from their writings. Many of these passages were here translated for the first time.

  4. Geographic Information Processings for Astronomical Site Survey

    Science.gov (United States)

    Wu, N.; Liu, Y.; Zhao, M. Y.

    2015-01-01

    The geographic information is of great importance for the site survey of ground-based telescopes. Especially, an effective utilization of the geographic information system (GIS) has been one of the most significant methods for the remote analysis of modern site survey. The astronomical site survey should give consideration to the following geographical conditions: a large relative fall, convenient traffic conditions, and far away from populated areas. Taking into account of the convenience of construction and maintenance of the observatories as well as the living conditions of the scientists-in-residence, the optimum candidate locations may meet the conditions to be at a altitude between 3000 m and 5000 m and within one-hour drive from villages/towns. In this paper, as an example, we take the regions of the Great Baicao mountain ridge at Dayao county in Yunnan province to research the role of the GIS for site survey task. The results indicate that the GIS can provide accurate and intuitive data for us to understand the three dimensional landforms, rivers, roads, villages, and the distributions of the electric power as well as to forecast the tendency of the population and city development around. According to the analysis based on the GIS, we find that the top of the Great Baicao mountain ridge is flat and droughty. There are few inhabitants to distribute around the place while the traffic conditions are convenient. Moreover, it is a natural conservation area protected by the local government, and no industry with pollution sources exists in this region. Its top is 1500 m higher than the nearby village 10 km away, and 1800 m higher than the town center 50 km away. The Great Baicao mountain ridge is definitely an isolated peak in the area of the Yi nationality of Yunnan. Therefore, the GIS data analysis is a very useful for the remote investigation stage for site survey, and the GIS is the indispensable source for modern astronomical site survey.

  5. US Astronomers Access to SIMBAD in Strasbourg

    Science.gov (United States)

    Oliversen, Ronald (Technical Monitor); Eichhorn, Guenther

    2004-01-01

    During the last year the US SIMBAD Gateway Project continued to provide services like user registration to the US users of the SIMBAD database in France. Currently there are over 4500 US users registered. We also provided user support by answering questions from users and handling requests for lost passwords when still necessary. Even though almost all users now access SIMBAD without a password, based on hostnames/IP addresses, there are still some users that need individual passwords. We continued to maintain the mirror copy of the SIMBAD database on a server at SAO. This allows much faster access for the US users. During the past year we again moved this mirror to a faster server to improve access for the US users. We again supported a demonstration of the SIMBAD database at the meeting of the American Astronomical Society in January. We provided support for the demonstration activities at the SIMBAD booth. We paid part of the fee for the SIMBAD demonstration. We continued to improve the cross-linking between the SIMBAD project and the Astrophysics Data System. This cross-linking between these systems is very much appreciated by the users of both the SIMBAD database and the ADS Abstract Service. The mirror of the SIMBAD database at SA0 makes this connection faster for the US astronomers. We exchange information between the ADS and SIMBAD on a daily basis. During the last year we also installed a mirror copy of the Vizier system from the CDS, in addition to the SIMBAD mirror.

  6. US Gateway to SIMBAD Astronomical Database

    Science.gov (United States)

    Eichhorn, G.; Oliversen, R. (Technical Monitor)

    1999-01-01

    During the last year the US SIMBAD Gateway Project continued to provide services like user registration to the US users of the SIMBAD database in France. Currently there are over 3400 US users registered. We also provide user support by answering questions from users and handling requests for lost passwords when still necessary. We have implemented in cooperation with the CDS SIMBAD project access to the SIMBAD database for US users on an Internet address basis. This allows most US users to access SIMBAD without having to enter passwords. We have maintained the mirror copy of the SIMBAD database on a server at SAO. This has allowed much faster access for the US users. We also supported a demonstration of the SIMBAD database at the meeting of the American Astronomical Society in January. We shipped computer equipment to the meeting and provided support for the demonstration activities at the SIMBAD booth. We continued to improve the cross-linking between the SIMBAD project and the Astrophysics Data System. This cross-linking between these systems is very much appreciated by the users of both the SIMBAD database and the ADS Abstract Service. The mirror of the SIMBAD database at SAO makes this connection faster for the US astronomers. We exchange information between the ADS and SIMBAD on a daily basis. The close cooperation between the CDS in Strasbourg and SAO, facilitated by this project, is an important part of the astronomy-wide digital library initiative called Urania. It has proven to be a model in how different data centers can collaborate and enhance the value of their products by linking with other data centers.

  7. World's fastest and most sensitive astronomical camera

    Science.gov (United States)

    2009-06-01

    The next generation of instruments for ground-based telescopes took a leap forward with the development of a new ultra-fast camera that can take 1500 finely exposed images per second even when observing extremely faint objects. The first 240x240 pixel images with the world's fastest high precision faint light camera were obtained through a collaborative effort between ESO and three French laboratories from the French Centre National de la Recherche Scientifique/Institut National des Sciences de l'Univers (CNRS/INSU). Cameras such as this are key components of the next generation of adaptive optics instruments of Europe's ground-based astronomy flagship facility, the ESO Very Large Telescope (VLT). ESO PR Photo 22a/09 The CCD220 detector ESO PR Photo 22b/09 The OCam camera ESO PR Video 22a/09 OCam images "The performance of this breakthrough camera is without an equivalent anywhere in the world. The camera will enable great leaps forward in many areas of the study of the Universe," says Norbert Hubin, head of the Adaptive Optics department at ESO. OCam will be part of the second-generation VLT instrument SPHERE. To be installed in 2011, SPHERE will take images of giant exoplanets orbiting nearby stars. A fast camera such as this is needed as an essential component for the modern adaptive optics instruments used on the largest ground-based telescopes. Telescopes on the ground suffer from the blurring effect induced by atmospheric turbulence. This turbulence causes the stars to twinkle in a way that delights poets, but frustrates astronomers, since it blurs the finest details of the images. Adaptive optics techniques overcome this major drawback, so that ground-based telescopes can produce images that are as sharp as if taken from space. Adaptive optics is based on real-time corrections computed from images obtained by a special camera working at very high speeds. Nowadays, this means many hundreds of times each second. The new generation instruments require these

  8. Combination of the H1 and ZEUS inclusive cross-section measurements at proton beam energies of 460 GeV and 575 GeV and tests of low Bjorken-x phenomenological models

    Energy Technology Data Exchange (ETDEWEB)

    Belov, Pavel

    2013-06-15

    A combination is presented of the inclusive neutral current e{sup {+-}}p scattering cross section data collected by the H1 and ZEUS collaborations during the last months of the HERA II operation period with proton beam energies E{sub p} of 460 and 575 GeV. The kinematic range of the cross section data covers low absolute four-momentum transfers squared, 1.5 GeV{sup 2} {<=} Q{sup 2} {<=} 110 GeV{sup 2}, small values of Bjorken-x, 2.8.10{sup -5} {<=} x {<=} 1.5.10{sup -2}, and high inelasticity y {<=} 0.85. The combination algorithm is based on the method of least squares and takes into account correlations of the systematic uncertainties. The combined data are used in the QCD fits to extract the parton distribution functions. The phenomenological low-x dipole models are tested and parameters of the models are obtained. A good description of the data by the dipole model taking into account the evolution of the gluon distribution is observed. The longitudinal structure function F{sub L} is extracted from the combination of the currently used H1 and ZEUS reduced proton beam energy data with previously published H1 nominal proton beam energy data of 920 GeV. A precision of the obtained values of F{sub L} is improved at medium Q{sup 2} compared to the published results of the H1 collaboration.

  9. Planet Formation in Action? - Astronomers may have found the first object clearing its path in the natal disc surrounding a young star

    Science.gov (United States)

    2011-02-01

    gap in the dust disc around T Cha was a smoking gun, and we asked ourselves: could we be witnessing a companion digging a gap inside its protoplanetary disc?" However, finding a faint companion so close to a bright star is a huge challenge and the team had to use the VLT instrument NACO in a novel and powerful way, called sparse aperture masking, to reach their goal [4]. After careful analysis they found the clear signature of an object located within the gap in the dust disc, about one billion kilometres from the star - slightly further out than Jupiter is within our Solar System and close to the outer edge of the gap. This is the first detection of an object much smaller than a star within a gap in the planet-forming dust disc around a young star. The evidence suggests that the companion object cannot be a normal star [5] but it could be either a brown dwarf [6] surrounded by dust or, most excitingly, a recently formed planet. Huélamo concludes: "This is a remarkable joint study that combines two different state-of-the-art instruments at ESO's Paranal Observatory. Future observations will allow us to find out more about the companion and the disc, and also understand what fuels the inner dusty disc." Notes [1] The transitional discs can be spotted because they give off less radiation at mid-infrared wavelengths. The clearing of the dust close to the star and the creation of gaps and holes can explain this missing radiation. Recently formed planets may have created these gaps, although there are also other possibilities. [2] T Cha is a T Tauri star, a very young star that is still contracting towards the main sequence. [3] The astronomers used the AMBER instrument (Astronomical Multi-BEam combineR) and the VLTI to combine the light from all four of the 8.2-metre VLT Unit Telescopes and create a "virtual telescope" 130 metres across. [4] NACO (or NAOS-CONICA in full) is an adaptive optics instrument attached to ESO's Very Large Telescope. Thanks to adaptive optics

  10. Software Package for Preparing and Processing of an Astronomical Observation

    Science.gov (United States)

    Vaduvescu, Ovidiu; Birlan, Mirel

    This paper presents an astronomical software package which draws celestial charts. It was conceived taking into account the technical possibilities available for the Romanian astronomers and the actual trend of the observational astronomy. The software package, now to its third version, comes to decrease the time to prepare an observation and to perform accurate charts for searching and identification.

  11. Project ASTRO: How-To Manual for Teachers and Astronomers.

    Science.gov (United States)

    Richter, Jessica; Fraknoi, Andrew

    Project ASTRO is an innovative program to support science education by linking teachers and students in grades 4-9 with amateur and professional astronomers with the overall goal being to increase students' interest in astronomy and science in general. This manual was designed for teachers, amateur and professional astronomers, youth group…

  12. Astronomical Books and Charts in the Book of Bibliographie Coreenne

    Directory of Open Access Journals (Sweden)

    Ki-Won Lee

    2008-06-01

    Full Text Available We investigate astronomical materials listed in the book of Bibliographie Coreenne written by Maurice Courant. He classified ancient Korean books into nine Divisions (部 and thirty six Classes (類, and published them as three volumes (ranging from 1894 to 1896 and one supplement (in 1901. In total, 3,821 books including astronomical ones are listed together with information on physical size, possessional place, bibliographical note, and so forth. Although this book is an essential one in the field of Korea bibliography and contains many astronomical materials such as Cheon-Mun-Ryu-Cho 天文類抄, Si-Heon-Seo 時憲書, and Cheon-Sang-Yeol-Cha-Bun-Ya-Ji-Do 天象列次分野之圖, it has not been well known to the public nor to astronomical society. Of 3,821 catalogues, we found that about 50 Items (種 are related to astronomy or astrology, and verified that most of them are located in the Kyujanggak Royal Library 奎章閣. We also found an unknown astronomical chart, Hon-Cheon-Chong-Seong-Yeol-Cha-Bun-Ya-Ji-Do 渾天總星列次分野之圖. Because those astronomical materials are not well known to international astronomical community and there have been few studies on the materials in Korea, we here introduce and review them, particularly with the astronomical viewpoint.

  13. Astronomical Books and Charts in the Book of Bibliographie Coreenne

    Science.gov (United States)

    Lee, Ki-Won; Yang, Hong-Jin; Park, Myeong-Gu

    2008-06-01

    We investigate astronomical materials listed in the book of Bibliographie Coréenne written by Maurice Courant. He classified ancient Korean books into nine Divisions (?) and thirty six Classes (?), and published them as three volumes (ranging from 1894 to 1896) and one supplement (in 1901). In total, 3,821 books including astronomical ones are listed together with information on physical size, possessional place, bibliographical note, and so forth. Although this book is an essential one in the field of Korea bibliography and contains many astronomical materials such as Cheon-Mun-Ryu-Cho ????, Si-Heon-Seo ??????, and Cheon-Sang-Yeol-Cha-Bun-Ya-Ji-Do ????????, it has not been well known to the public nor to astronomical society. Of 3,821 catalogues, we found that about 50 Items (?) are related to astronomy or astrology, and verified that most ! of them are located in the Kyujanggak Royal Library ???. We also found an unknown astronomical chart, Hon-Cheon-Chong-Seong-Yeol-Cha-Bun-Ya-Ji-Do ??????????. Because those astronomical materials are not well known to international astronomical community and there have been few studies on the materials in Korea, we here introduce and review them, particularly with the astronomical viewpoint.

  14. AIBLE: An Inquiry-Based Augmented Reality Environment for Teaching Astronomical Phenomena

    OpenAIRE

    Fleck, Stéphanie; Simon, Gilles; Bastien, Christian

    2014-01-01

    International audience; We present an inquiry-based augmented reality (AR) learning environment (AIBLE) designed for teaching basic astronomical phenomena in elementary classroom (children of 8-11 years old). The novelty of this environment lies in the combination of both Inquiry Based Sciences Education and didactics principles with AR features. This environment was user tested by 69 pupils in order to assess its impact on learning. The main results indicate that AIBLE provides new opportuni...

  15. How Astronomers Focused the Scope of their Discussions: The Formation of the Astronomical Society of Australia

    Science.gov (United States)

    Lomb, Nick

    2015-05-01

    Scientific societies provide an important forum for scientists to meet and exchange ideas. In the early days of European settlement in Australia the few people interested in the sciences joined together to form societies that embraced all their individual disciplines. From 1888 the Australasian Association for the Advancement of Science with its different sections allowed a growing number of astronomers to share meetings only with researchers in the closely allied fields of mathematics and physics. Eventually, all three of these groups formed their own societies with the Astronomical Society of Australia (ASA) being the last in 1966. Archival records are used to illustrate how the formation of the ASA came about and to identify the people involved. The makeup of Australian astronomy at that period and some of its research fields are looked at, as well as the debates and discussions in the Society's first year while its future structure and role were established.

  16. Astronomical Orientation in the Ancient Dacian Sanctuaries of Romania

    Science.gov (United States)

    Stănescu, Florin

    Sarmizegetusa Regia, the former capital city of the Dacians' kingdom, is situated in the Şureanu (Orăştie) Mountains in the Southern Carpathians, Romania. This chapter reviews, from the astronomical point of view, two of the monuments located on its Sacred Terrace - the altar known as the "Andesite Sun" and the Central Apse of the Great Round Sanctuary - as well as sanctuaries at the nearby site of Costeşti. Astronomical analyses taking into consideration (a) the astronomical-geometrical methods of the time (the analemma of a sundial after Vitruvius and the stereographical projection in the sense of Hipparchus), (b) astronomical instruments of the time (the gnomon, the sundial and the astrolabe), and (c) other instruments known to the Dacians (the compass), have concluded that these monuments may have enabled the Dacians to carry out a number of astronomical observations. This would confirm several reports by contemporary historians regarding the Dacians' knowledge of astronomy.

  17. The Role of Amateur Astronomy to Outreach Astronomical Knowledge

    Science.gov (United States)

    Khachatryan, Vachik; Voskanyan, Tsovak

    2016-12-01

    It is known that in the educational system of republic the astronomy is not taught as a separate subject. Moreover, there are no telescopes in the vast majority of schools. "Goodricke John" NGO of amateur astronomers tries to fill this gap by organizing practical lessons of astronomy in secondary schools. NGO is equipped with high quality portable amateur telescopes and organizes periodic mass observations of planets, Moon, star clusters, nebulae in Yerevan and in regions. In addition, mass observations of rare astronomical phenomena are organized, such as the transit of Venus and Mercury across the disk of the Sun. Being the only NGO of amateur astronomers, it has a goal to contribute to publicizing astronomical knowledge and to ensure the availability of astronomical equipment, telescopes also to those segments of the society who have no opportunity to deal with them, in particular, persons with disabilities, prisoners, persons with disabilities, prisoners, soldiers, children from orphanages, school children and others.

  18. Linking Young Astronomers in Southeast Asia: The SEAYAC Story

    Science.gov (United States)

    Dionisio Sese, Rogel Mari

    2015-08-01

    The importance of involving young astronomers in developing astronomy cannot be overemphasized. This is very much true in areas where astronomy is still an emerging and minor field, such as in the Southeast Asian (SEA) region. However, recent years have seen a sudden spark of interest in developing professional astronomy within SEA, primarily for young astronomers and students. This was especially highlighted during the 2009 International Year of Astronomy. In this presentation, we introduce the Southeast Asian Young Astronomers Collaboration (SEAYAC), a recently formed organization that aims to provide a venue for professional and personal interaction for young astronomers in the SEA region. Here we present the background and rationale behind the formation of SEAYAC, its current status as well as planned future activities aimed at developing collaborations between young astronomers in the SEA region. We will also discuss the problems and challenges being faced by SEAYAC as well as its future plan of actions.

  19. IYL Blog: Astronomers travel in time and space with light

    Science.gov (United States)

    Mather, John C.

    2015-01-01

    also using light to find out whether we are alone in the universe. The Kepler observatory showed that thousands of stars blink a little when their orbiting planets pass between us and them, and other observatories use light to measure the wobble of stars as their planets pull on them. Eventually, we will find out whether planets like Earth have atmospheres like Earth's too - with water, carbon dioxide, oxygen, methane, and other gases that would be evidence of photosynthetic life. I think in a few decades we will have evidence that some planets do have life, and it will be done using light for remote chemical analysis. Also, astronomers at the SETI project are using light (long wavelength light we can pick up with radio telescopes) to look for signals from intelligent civilizations. That's a harder project because we don't know what to look for. But if we wanted to send signals all the way across the Milky Way, we could do it with laser beams, and if somebody over there knew what to look for, he or she could decode the message. On with the search! Dr. John C. Mather is a Senior Astrophysicist and is the Senior Project Scientist for the James Webb Space Telescope at NASA's Goddard Space Flight Center in Greenbelt, MD. His research centers on infrared astronomy and cosmology. With the Cosmic Background Explorer (COBE) team, he showed that the cosmic microwave background radiation has a blackbody spectrum within 50 parts per million, confirming the expanding universe model (aka the Big Bang Theory) to extraordinary accuracy, and initiating the study of cosmology as a precision science. The COBE team also made the first map of the hot and cold spots in the background radiation. The COBE maps have been confirmed and improved by two succeeding space missions, the Wilkinson Microwave Anisotropy Probe (WMAP, built by GSFC with Princeton University), and the Planck mission built by ESA. Based on these maps, astronomers have now developed a "standard model" of cosmology and have

  20. Staring/focusing lobster-eye hard x-ray imaging for non-astronomical objects

    Science.gov (United States)

    Gertsenshteyn, Michael; Jannson, Tomasz; Savant, Gajendra

    2005-08-01

    A new approach to hard X-ray imaging is proposed, based on staring optics consisting of a lobster-eye lens. This new Staring Imaging Lobster-Eye X-Ray approach is especially suited to X-ray lobster-eye imaging of non-astronomical objects at finite distances, because the staring optics replacing the standard scanning optics, result in an extremely efficient power budget, making possible not only the use of low-efficiency Compton backscattering but also operation with low-flux X-ray beams, increasing operator safety. The lobster-eye optics, consisting of square-cross-section microchannels, transmit an X-ray beam by total external reflection. This mode of operation has already been verified for viewing astronomical objects. Its major challenge is minimizing image defocusing by apodization. For this purpose, a new lens imaging equation is derived, and a new local optical axis concept is defined. Applications include medical imaging, cargo inspection, non-destructive testing, industrial and security safeguards, and surveillance.

  1. 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 ...

  2. The impact of astronomical forcing on the Late Devonian greenhouse climate

    Science.gov (United States)

    De Vleeschouwer, David; Crucifix, Michel; Bounceur, Nabila; Claeys, Philippe

    2014-09-01

    The geological record of the Paleozoic often exhibits cyclic features, in many cases the result of changes in paleoclimate. However, a thorough understanding of the processes that were driving Paleozoic climate change has not yet been reached. The main reason is relatively poor time-control on Paleozoic paleoclimate proxy records. This problem can be overcome by the identification of cyclic features resulting from astronomical climate forcing in the stratigraphic record. To correctly identify these cyclic features, it is necessary to quantify the effects of astronomical climate forcing under conditions different from today. In this work, we apply Late Devonian (375 Ma) boundary conditions to the Hadley Centre general circulation model (HadSM3). We estimate the response of Late Devonian climate to astronomical forcing by keeping all other forcing factors (e.g. paleogeography, pCO2, vegetation distribution) fixed. Thirty-one different "snapshots" of Late Devonian climate are simulated, by running the model with different combinations of eccentricity (e), obliquity (ε) and precession (ω˜). From the comparison of these 31 simulations, it appears that feedback mechanisms play an important role in the conversion of astronomically driven insolation variations into climate change, such as the formation of sea-ice and the development of an extensive snow cover on Gondwana. We compare the "median orbit" simulation to lithic indicators of paleoclimate to evaluate whether or not HadSM3 validly simulates Late Devonian climates. This comparison suggests that the model correctly locates the major climate zones. This study also tests the proposed link between the formation of ocean anoxia and high eccentricity (De Vleeschouwer et al., 2013) by comparing the δ18Ocarb record of the Frasnian-Famennian boundary interval from the Kowala section (Poland) with a simulated time series of astronomically forced changes in mean annual temperature at the paleolocation of Poland. The

  3. Database-Driven Analyses of Astronomical Spectra

    Science.gov (United States)

    Cami, Jan

    2012-03-01

    Spectroscopy is one of the most powerful tools to study the physical properties and chemical composition of very diverse astrophysical environments. In principle, each nuclide has a unique set of spectral features; thus, establishing the presence of a specific material at astronomical distances requires no more than finding a laboratory spectrum of the right material that perfectly matches the astronomical observations. Once the presence of a substance is established, a careful analysis of the observational characteristics (wavelengths or frequencies, intensities, and line profiles) allows one to determine many physical parameters of the environment in which the substance resides, such as temperature, density, velocity, and so on. Because of this great diagnostic potential, ground-based and space-borne astronomical observatories often include instruments to carry out spectroscopic analyses of various celestial objects and events. Of particular interest is molecular spectroscopy at infrared wavelengths. From the spectroscopic point of view, molecules differ from atoms in their ability to vibrate and rotate, and quantum physics inevitably causes those motions to be quantized. The energies required to excite vibrations or rotations are such that vibrational transitions generally occur at infrared wavelengths, whereas pure rotational transitions typically occur at sub-mm wavelengths. Molecular vibration and rotation are coupled though, and thus at infrared wavelengths, one commonly observes a multitude of ro-vibrational transitions (see Figure 13.1). At lower spectral resolution, all transitions blend into one broad ro-vibrational molecular band. The isotope. Molecular spectroscopy thus allows us to see a difference of one neutron in an atomic nucleus that is located at astronomical distances! Since the detection of the first interstellar molecules (the CH [21] and CN [14] radicals), more than 150 species have been detected in space, ranging in size from diatomic

  4. Pulsed dose rate brachytherapy as the boost in combination with external beam irradiation in base of tongue cancer. Long-term results from a uniform clinical series

    Directory of Open Access Journals (Sweden)

    Bengt Johansson

    2011-03-01

    Full Text Available Purpose: To evaluate long time outcome with regard to local tumour control, side effects and quality of life of combined pulsed dose rate (PDR boost and hyperfractionated accelerated external beam radiotherapy (EBRT for primary base of tongue (BOT cancers. Material and methods: Between 1994 and 2007, the number of 83 patients were treated with primary T1-T4 BOT cancers. Seven patients (8% were T1-2N0 (AJCC stage I-II and 76 (92% patients were T1-2N+ or T3-4N0-2 (AJCC stage III-IV. The mean estimated primary tumour volume was 15.4 (1-75 cm3. EBRT was given with 1.7 Gy bid to 40.8 Gy to primary tumour and bilateral neck lymph nodes in 2.5 weeks. PDR boost of 35 Gy and a neck dissection in clinical node positive case was performed 2-3 weeks later. The patients were followed for a median of 54 (2-168 months. Results: The 2-, 5- and 10-years rates of actuarial local control were 91%, 89% and 85%, overall survival 85%, 65% and 44%, disease free survival 86%, 80% and 76%, respectively. The regional control rate was 95%. Six patients (7% developed distant metastases. A dosimetric analysis showed a mean of 100% isodose volume of 58.2 (16.7-134 cm3. In a review of late complications 11 cases of minor (13% and 5 of major soft tissue necroses (6%, as well as 6 cases of osteoradionecroses (7% were found. The patients median subjective SOMA/LENT scoring at last follow up was as follow: grade 0 for pain and trismus, grade 1 for dysphagia and taste alteration, and grade 2 for xerostomia. Global visual- analogue-scale (VAS scoring of quality of life was 8. Conclusion: Local and regional tumour control rate was excellent in this treatment protocol. The data shows the PDR boost as at least as effective as published continuous low dose rate (CLDR results.

  5. Survival Outcomes of Dose-Escalated External Beam Radiotherapy versus Combined Brachytherapy for Intermediate and High Risk Prostate Cancer Using the National Cancer Data Base.

    Science.gov (United States)

    Amini, Arya; Jones, Bernard; Jackson, Matthew W; Yeh, Norman; Waxweiler, Timothy V; Maroni, Paul; Kavanagh, Brian D; Raben, David

    2016-05-01

    We evaluated survival outcomes between dose-escalated EBRT (external beam radiotherapy) vs EBRT plus brachytherapy for intermediate and high risk prostate cancer using NCDB (National Cancer Data Base). Patients with cN0M0 prostate cancer treated from 2004 to 2006 were divided into radiotherapy comparison groups, including EBRT alone (75.6 to 81 Gy) and EBRT (40 to 50.4 Gy) plus brachytherapy with EBRT delivered at 1.8 to 2.0 Gy per fraction. Brachytherapy data were limited to yes/no with no information on modality, dose or schedule. Eligible patients were known to have received androgen deprivation therapy. Overall survival was evaluated using multivariate Cox regression and propensity score matched analyses. Of the 20,279 study patients with prostate cancer, including 12,617 at intermediate risk and 7,662 at high risk, 71.3% received EBRT alone and 28.7% received EBRT plus brachytherapy. Median followup was 82 months (range 3 to 120) and median age was 70 years (range 36 to 90). On multivariate analysis compared to EBRT alone (75.6 to 81 Gy) EBRT plus brachytherapy was associated with improved survival (HR 0.75, p <0.001). This significance remained consistent for intermediate and high risk when analyzed separately (HR 0.73 and 0.76, respectively, each p <0.001). However on subset analysis compared to very high dose EBRT alone (79.2 to 81 Gy) in all patients combined EBRT plus brachytherapy was not associated with improved survival (HR 0.91, p = 0.083). Compared to EBRT (75.6 to 81 Gy) we observed an association of EBRT plus brachytherapy with a decreased risk of death in men with intermediate and high risk prostate cancer. However this association was no longer significant when EBRT doses of 79.2 to 81 Gy were used. Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  6. Radiation events in astronomical CCD images

    Energy Technology Data Exchange (ETDEWEB)

    Smith, A.R.; McDonald, R.J.; Hurley, D.L.; Holland, S.E.; Groom, D.E.; Brown, W.E.; Gilmore, D.K.; Stover, R.J.; Wei, M.

    2001-12-18

    The remarkable sensitivity of depleted silicon to ionizing radiation is a nuisance to astronomers. ''Cosmic rays'' degrade images because of struck pixels, leading to modified observing strategies and the development of algorithms to remove the unwanted artifacts. In the new-generation CCD's with thick sensitive regions, cosmic-ray muons make recognizable straight tracks and there is enhanced sensitivity to ambient gamma radiation via Compton-scattered electrons (''worms''). Beta emitters inside the dewar, for example high-potassium glasses such as BK7, also produce worm-like tracks. The cosmic-ray muon rate is irreducible and increases with altitude. The gamma rays are mostly by-products of the U and Th decay chains; these elements always appear as traces in concrete and other materials. The Compton recoil event rate can be reduced significantly by the choice of materials in the environment and dewar and by careful shielding. Telescope domes appear to be significantly cleaner than basement laboratories and Coude spectrograph rooms. Radiation sources inside the dewar can be eliminated by judicious choice of materials. Cosmogenic activation during high-altitude flights does not appear to be a problem. Our conclusions are supported by tests at the Lawrence Berkeley National Laboratory low-level counting facilities in Berkeley and at Oroville, California (180 m underground).

  7. Is astronomical research appropriate for developing countries?

    Science.gov (United States)

    Snowden, Michael S.

    An unproductive 45-cm astronomical telescope, given by JICA (Japan) to Sri Lanka, raises general questions as to the reasons for unproductive pure science in developing countries. Before installation, site, maintenance, and scientific objectives were discussed. The facility was launched with a conference organised by the UN Office for Outer Space Affairs. Unfortunately, no research or significant education has resulted after four years. The annual operating cost is U.S. $5000 per year, including salary for a trainee, maintenance, and a modest promotional programme. Comparison with a similar installation in Auckland suggests lack of funding or technical competence do not explain the failure in Sri Lanka. The facility in New Zealand, on the roof of Auckland University's Physics Department, has a slightly smaller budget but has led to modest but useful research and teaching. Lack of financial backing and expertise are often blamed for weak science in developing countries, but examination shows most of these countries have adequately skilled people, and plenty of resources for religion and military. General lack of motivation for science appears to be the principal reason. This lack of interest and highly inefficient bureaucracies are common to scientifically unproductive countries. They mostly lack the cultural and philosophical base of the European Renaissance that motivate the pursuit of modern science, an activity that violates human preferences. There are excellent facilities (ESO, SAAO, Cerro Tololo, and GONG) in some of these same countries, when administered from the West.

  8. Book Review: Scientific Writing for Young Astronomers

    Science.gov (United States)

    Uyttenhove, Jos

    2011-12-01

    EDP Sciences, Les Ulis, France. Part 1 : 162 pp. € 35 ISBN 978-2-7598-0506-8 Part 2 : 298 pp. € 60 ISBN 978-2-7598-0639-3 The journal Astronomy & Astrophysics (A&A) and EDP Sciences decided in 2007 to organize a School on the various aspects of scientific writing and publishing. In 2008 and 2009 Scientific Writing for Young Astronomers (SWYA) Schools were held in Blankenberge (B) under the direction of Christiaan Sterken (FWO-VUB). These two books (EAS publication series, Vol. 49 and 50) reflect the outcome of these Schools. Part 1 contains a set of contributions that discuss various aspects of scientific publication; it includes A&A Editors' view of the peer review and publishing process. A very interesting short paper by S.R. Pottasch (Kapteyn Astronomical Institute, Groningen, and one of the two first Editors-in Chief of A&A) deals with the history of the creation of the journal Astronomy & Astrophysics. Two papers by J. Adams et al. (Observatoire de Paris) discuss language editing, including a detailed guide for any non-native user of the English language. In 2002 the Board of Directors decided that all articles in A&A must be written in clear and correct English. Part 2 consists of three very extensive and elaborated papers by Christiaan Sterken, supplying guidelines to PhD students and postdoctoral fellows to help them compose scientific papers for different forums (journals, proceedings, thesis, etc.). This part is of interest not only for young astronomers but it is very useful for scholars of all ages and disciplines. Paper I "The writing process" (60 pp.) copes with the preparation of manuscripts, with communicating with editors and referees and with avoiding common errors. Delicate problems on authorship, refereeing, revising multi-authored papers etc. are treated in 26 FAQ's. Paper II "Communication by graphics" (120 pp.) is entirely dedicated to the important topic of communication with images, graphs, diagrams, tables etc. Design types of graphs

  9. An embeddable control system for astronomical instrumentation

    Science.gov (United States)

    Cirami, Roberto; Comari, Maurizio; Corte, Claudio; Golob, Damjan; Di Marcantonio, Paolo; Plesko, Mark; Pucillo, Mauro; Santin, Paolo; Sekoranja, Matej; Vuerli, Claudio

    2004-09-01

    Large experimental facilities, like telescopes and focal plane instrumentation in the astronomical domain, are becoming more and more complex and expensive, as well as control systems for managing such instruments. The general trend, as can be learned by realizations carried out in the most recent years, clearly drives to most cost-effective solutions: widespread, stable standards in the software field, COTS (commercial off-the-shelf) components and industry standards in the hardware field. Therefore a new generation of control system products needs to be developed, in order to help the scientific community to minimize the cost and efforts required for maintenance and control of their facilities. In the spirit of the aforementioned requirements and to provide a low-cost software and hardware environment we present a working prototype of a control system, based on RTAI Linux and on ACS (Advanced Control System) framework ported to an embedded platform. The hardware has been chosen among COTS components: a PC/104+ platform equipped with a PMAC2A motion controller card and a commercial StrongARM single board controller. In this way we achieved a very powerful, inexpensive and robust real-time control system which can be used as a general purpose building block in the design of new instruments and could also be proposed as a standard in the field.

  10. An Astronomical Life Salted by Pure Chance

    Science.gov (United States)

    Kraft, Robert P.

    2009-09-01

    My childhood upbringing in no way suggested that I would become an astronomer, but accidents of fate pushed me in the direction of science, and I have benefited greatly from being in the right place at the right time. I grew up in Seattle, earned B.S. and M.S. degrees in mathematics at the University of Washington, and eventually a Ph.D. in astronomy from the University of California, Berkeley. I was a postdoc at the Mt. Wilson Observatory, an assistant professor at Indiana University, later the Yerkes Observatory (University of Chicago), and still later I became a staff member of the Mt. Wilson and Palomar Observatories. After several years, I returned to the University of California, this time with the Lick Observatory staff at its new academic home on the Santa Cruz campus, where I have been ever since. My research has focused on the relation of Cepheids and RR Lyrae stars to problems of Galactic structure, the binary nature of cataclysmic variables, the decay of angular momentum of solar type stars, and the chemical history of the Galaxy as revealed by the abundances of very old stars in globular clusters and the Galactic halo field. None of this work would have been possible without the help of excellent teachers and mentors, great colleagues, and superb postdocs and graduate students. Most of all, I am grateful for the educational opportunities afforded me by state-supported public Universities.

  11. Conceptualizing Astronomical Distances for Urban Populations

    Science.gov (United States)

    Popinchalk, Mark; Olson, Kristen; Ingber, Jenny; O'Brien, Mariel

    2017-01-01

    Students living in urban environments may have a washed-out night sky, but their enthusiasm for astronomy can still shine bright. As an educator, it can sometimes be a challenge to see the opportunities afforded by city living to the teaching of astronomy; however, several benefits can be identified. For example, the intrinsic understanding children have of the distances and scales involved in their everyday life is enhanced when they live in a regimented urban structure. This existing understanding of scale is critical to building a foundation for later conceptualizing of the universe.Leveraging the assets of New York City and the resources found in the American Museum of Natural History, The Science and Nature Program offers students (PreK through 8th grade) robust science learning experiences. To address concepts important for studying astronomy, we present a novel twist on the classic lesson “Earth as a Peppercorn,” by scaling the solar system to the size of New York City. Using local landmarks and their distance in relation to the Museum to represent the planets, students can use their prior knowledge of their surroundings to appreciate the impressive scale of our neighborhood in space in the context of their own neighborhoods. We correlate the activity with NGSS standards, present preliminary feedback on it’s success, and discuss the opportunities to apply a similar model lesson to other astronomical systems.

  12. Astronomers Find Enormous Hole in the Universe

    Science.gov (United States)

    2007-08-01

    Astronomers have found an enormous hole in the Universe, nearly a billion light-years across, empty of both normal matter such as stars, galaxies, and gas, and the mysterious, unseen "dark matter." While earlier studies have shown holes, or voids, in the large-scale structure of the Universe, this new discovery dwarfs them all. Void Illustration Hole in Universe revealed by its effect on Cosmic Microwave Background radiation. CREDIT: Bill Saxton, NRAO/AUI/NSF, NASA Click on image for page of graphics and detailed information "Not only has no one ever found a void this big, but we never even expected to find one this size," said Lawrence Rudnick of the University of Minnesota. Rudnick, along with Shea Brown and Liliya R. Williams, also of the University of Minnesota, reported their findings in a paper accepted for publication in the Astrophysical Journal. Astronomers have known for years that, on large scales, the Universe has voids largely empty of matter. However, most of these voids are much smaller than the one found by Rudnick and his colleagues. In addition, the number of discovered voids decreases as the size increases. "What we've found is not normal, based on either observational studies or on computer simulations of the large-scale evolution of the Universe," Williams said. The astronomers drew their conclusion by studying data from the NRAO VLA Sky Survey (NVSS), a project that imaged the entire sky visible to the Very Large Array (VLA) radio telescope, part of the National Science Foundation's National Radio Astronomy Observatory (NRAO). Their careful study of the NVSS data showed a remarkable drop in the number of galaxies in a region of sky in the constellation Eridanus. "We already knew there was something different about this spot in the sky," Rudnick said. The region had been dubbed the "WMAP Cold Spot," because it stood out in a map of the Cosmic Microwave Background (CMB) radiation made by the Wilkinson Microwave Anisotopy Probe (WMAP) satellite

  13. Model based systems engineering for astronomical projects

    Science.gov (United States)

    Karban, R.; Andolfato, L.; Bristow, P.; Chiozzi, G.; Esselborn, M.; Schilling, M.; Schmid, C.; Sommer, H.; Zamparelli, M.

    2014-08-01

    Model Based Systems Engineering (MBSE) is an emerging field of systems engineering for which the System Modeling Language (SysML) is a key enabler for descriptive, prescriptive and predictive models. This paper surveys some of the capabilities, expectations and peculiarities of tools-assisted MBSE experienced in real-life astronomical projects. The examples range in depth and scope across a wide spectrum of applications (for example documentation, requirements, analysis, trade studies) and purposes (addressing a particular development need, or accompanying a project throughout many - if not all - its lifecycle phases, fostering reuse and minimizing ambiguity). From the beginnings of the Active Phasing Experiment, through VLT instrumentation, VLTI infrastructure, Telescope Control System for the E-ELT, until Wavefront Control for the E-ELT, we show how stepwise refinements of tools, processes and methods have provided tangible benefits to customary system engineering activities like requirement flow-down, design trade studies, interfaces definition, and validation, by means of a variety of approaches (like Model Checking, Simulation, Model Transformation) and methodologies (like OOSEM, State Analysis)

  14. Astronomical Constraints on Quantum Cold Dark Matter

    Science.gov (United States)

    Spivey, Shane; Musielak, Z.; Fry, J.

    2012-01-01

    A model of quantum (`fuzzy') cold dark matter that accounts for both the halo core problem and the missing dwarf galaxies problem, which plague the usual cold dark matter paradigm, is developed. The model requires that a cold dark matter particle has a mass so small that its only allowed physical description is a quantum wave function. Each such particle in a galactic halo is bound to a gravitational potential that is created by luminous matter and by the halo itself, and the resulting wave function is described by a Schrödinger equation. To solve this equation on a galactic scale, we impose astronomical constraints that involve several density profiles used to fit data from simulations of dark matter galactic halos. The solutions to the Schrödinger equation are quantum waves which resemble the density profiles acquired from simulations, and they are used to determine the mass of the cold dark matter particle. The effects of adding certain types of baryonic matter to the halo, such as a dwarf elliptical galaxy or a supermassive black hole, are also discussed.

  15. The Blue Comet: A Railroad's Astronomical Heritage

    Science.gov (United States)

    Rumstay, Kenneth S.

    2009-01-01

    Between 1929 February 21 and 1941 September 27, the Central New Jersey Railroad operated a luxury passenger train between Jersey City and Atlantic City. Named The Blue Comet, the locomotive, tender, and coaches sported a unique royal blue paint scheme designed to evoke images of celestial bodies speeding through space. Inside each car were etched window panes and lampshades featuring stars and comets. And each coach sported the name of a famous comet on its side; these comets were of course named for their discoverers. Some of the astronomers honored in this unique fashion remain famous to this day, or at least their comets do. The names D'Arrest, Barnard, Encke, Faye, Giacobini, Halley, Olbers, Temple, Tuttle, and Westphal are familiar ones. But Biela, Brorsen, deVico, Spitaler, and Winnecke have now largely faded into obscurity; their stories are recounted here. Although more than sixty years have elapsed since its last run, The Blue Comet, perhaps the most famous passenger train in American history, lives on in the memories of millions of passengers and railfans. This famous train returned to the attention of millions of television viewers on the evening of 2007 June 3, in an episode of the HBO series The Sopranos. This work was supported by a faculty development grant from Valdosta State University.

  16. Spatial Statistical Analysis of Large Astronomical Datasets

    Science.gov (United States)

    Szapudi, Istvan

    2002-12-01

    The future of astronomy will be dominated with large and complex data bases. Megapixel CMB maps, joint analyses of surveys across several wavelengths, as envisioned in the planned National Virtual Observatory (NVO), TByte/day data rate of future surveys (Pan-STARRS) put stringent constraints on future data analysis methods: they have to achieve at least N log N scaling to be viable in the long term. This warrants special attention to computational requirements, which were ignored during the initial development of current analysis tools in favor of statistical optimality. Even an optimal measurement, however, has residual errors due to statistical sample variance. Hence a suboptimal technique with significantly smaller measurement errors than the unavoidable sample variance produces results which are nearly identical to that of a statistically optimal technique. For instance, for analyzing CMB maps, I present a suboptimal alternative, indistinguishable from the standard optimal method with N3 scaling, that can be rendered N log N with a hierarchical representation of the data; a speed up of a trillion times compared to other methods. In this spirit I will present a set of novel algorithms and methods for spatial statistical analyses of future large astronomical data bases, such as galaxy catalogs, megapixel CMB maps, or any point source catalog.

  17. Phase II multi-institutional clinical trial on a new mixed beam RT scheme of IMRT on pelvis combined with a carbon ion boost for high-risk prostate cancer patients.

    Science.gov (United States)

    Marvaso, Giulia; Jereczek-Fossa, Barbara A; Vischioni, Barbara; Ciardo, Delia; Giandini, Tommaso; Hasegawa, Azusa; Cattani, Federica; Carrara, Mauro; Ciocca, Mario; Bedini, Nice; Villa, Sergio; Morlino, Sara; Russo, Stefania; Zerini, Dario; Colangione, Sarah Pia; Panaino, Costanza Maria Vittoria; Fodor, Cristiana; Santoro, Luigi; Pignoli, Emanuele; Valvo, Francesca; Valdagni, Riccardo; De Cobelli, Ottavio; Orecchia, Roberto

    2017-05-12

    Definition of the optimal treatment schedule for high-risk prostate cancer is under debate. A combination of photon intensity modulated radiotherapy (IMRT) on pelvis with a carbon ion boost might be the optimal treatment scheme to escalate the dose on prostate and deliver curative dose with respect to normal tissue and quality of dose distributions. In fact, carbon ion beams offer the advantage to deliver hypofractionated radiotherapy (RT) using a significantly smaller number of fractions compared to conventional RT without increasing risks of late effects. This study is a prospective phase II clinical trial exploring safety and feasibility of a mixed beam scheme of carbon ion prostate boost followed by photon IMRT on pelvis. The study is designed to enroll 65 patients with localized high-risk prostate cancer at 3 different oncologic hospitals: Istituto Europeo di Oncologia, Fondazione IRCCS Istituto Nazionale dei Tumori, and Centro Nazionale di Adroterapia Oncologica. The primary endpoint is the evaluation of safety and feasibility with acute toxicity scored up to 1 month after the end of RT. Secondary endpoints are treatment early (3 months after the end of RT) and long-term tolerability, quality of life, and efficacy. The study is not yet recruiting; in silico studies are ongoing and we expect to start recruitment by 2017. The present clinical trial aims at improving the current treatment for high-risk prostate cancer, evaluating safety and feasibility of a new RT mixed-beam scheme including photons and carbon ions. Encouraging results are coming from carbon ion facilities worldwide on the treatment of different tumors including prostate cancers. Carbon ions combine physical properties allowing for high dose conformity and advantageous radiobiological characteristics. The proposed mixed beam treatment has the advantage to combine a photon high conformity standard of care IMRT phase with a hypofractionated carbon ion RT boost delivered in a short overall

  18. Are opthalmic hydrophobic coatings useful for astronomical optics?

    Science.gov (United States)

    Schwab, Christian; Phillips, Andrew C.

    2010-07-01

    Astronomical optics are often exposed to moisture and dust in observatory environments, which frequently compromises their high-performance coatings. Suitable protective layers to resist dust and moisture accumulation would be extremely advantageous, but have received scant attention thus far. Hydrophobic and scratch-resistant coatings, developed primarily for opthalmic use, exhibit several attractive properties for astronomical optics. We examine the properties of one such coating and its applicability to astronomical mirrors and lenses. This includes efficiency of dust removal, abrasion resistance, moisture resistance, ease of stripping, and transmission across a wide wavelength range.

  19. Astronomical Dating of Edvard Munch's Summer Sky Paintings

    Science.gov (United States)

    Pope, Ava; Olson, Donald

    2010-02-01

    Norwegian painter Edvard Munch, most famous for The Scream, created many spectacular works depicting the skies of Norway. Our Texas State group used astronomical methods to analyze three of these paintings: Starry Night, The Storm, and Sunrise in Asgardstrand. Astronomical dating of these paintings has some importance because the precise days when Munch visited Asgardstrand are unknown. Our research group traveled to Norway in August 2008 to find the locations from which Munch painted these three works. We then used astronomical calculations, topographical analysis, historical photographs, and weather records to determine the precise dates and times for the scenes depicted in these paintings. )

  20. Serbian Astronomers in Science Citation Index in the XX Century

    Science.gov (United States)

    Dimitrijevic, Milan S.

    The book is written paralelly in Serbian and English. The presence of works of Serbian astronomers and works in astronomical journals published by other Serbian scientists, in Science Citation Index within the period from 1945 up to the end of 2000, has been analyzed. Also is presented the list of 38 papers which had some influence on the development of astronomy in the twentieth century. A review of the development of astronomy in Serbia in the last century is given as well. Particular attention is payed to the Astronomical Observatory, the principal astronomical institution in Serbia, where it is one of the oldest scientific organizations and the only autonomous astronomical institute. Its past development forms an important part of the history of science and culture in these regions. In the book is also considered and the history of the university teaching of astronomy in Serbia after the second world war. First of all the development of the Chair of Astronomy at the Faculty of Mathematics in Belgrade, but also the teaching of astronomy at University in Novi Sad, Ni and Kragujevac is discussed. In addition to professional Astronomy, well developed in Serbia is also the amateur Astronomy. In the review is first of all included the largest and the oldest organization of amateur-astronomers in Serbia, founded in 1934. Besides, here are the Astronomical Society "Novi Sad", ADNOS and Research Station "Petnica". In Valjevo, within the framework of the Society of researchers "Vladimir Mandic - Manda", there is active also the Astronomical Group. In Kragujevac, on the roof of the Institute of Physics of the Faculty of Sciences, there is the "Belerofont" Observatory. In Ni, at the close of the sixties and the start of the seventies, there was operating a branch of the Astronomical Society "Rudjer Bokovic", while at the Faculty of Philosophy there existed in the period 1976-1980 the "Astro-Geophysical Society". In the year 1996 there was founded Astronomical Society

  1. The Moon in Close-up A Next Generation Astronomer's Guide

    CERN Document Server

    Wilkinson, John

    2010-01-01

    Information collected by recent space probes sent to explore the Moon by the USA, the European Space Agency, Japan, China and India has changed our knowledge and understanding of the Moon, particularly its geology, since the Apollo missions. This book presents those findings in a way that will be welcomed by amateur astronomers, students, educators and anyone interested in the Moon. Enhanced by many colour photos, it combines newly acquired scientific understanding with detailed descriptions and labelled photographic maps of the lunar surface. Guided by observation methods explained in the book and 17 Study Areas presented and carefully explained in the last chapter, amateur astronomers can observe these features from Earth using telescopes and binoculars. Readers who consult the photographic maps will gain a better understanding about the Moon’s topography and geology. The book is rounded out by a helpful glossary.

  2. Beam Diagnostics

    CERN Document Server

    Raich, U

    2013-01-01

    As soon as the first particles emerge from an ion source, the source characteristics need to be determined. The total beam intensity, the transverse particle distributions, the beam divergence and emittance as well as the longitudinal parameters of the beam must be measured. This chapter provides an overview of typical measurement methods and the instruments used, and shows the results obtained.

  3. Revolutionary visible and infrared sensor detectors for the most advanced astronomical AO systems

    Science.gov (United States)

    Feautrier, Philippe; Gach, Jean-Luc; Guieu, Sylvain; Downing, Mark; Jorden, Paul; Rothman, Johan; de Borniol, Eric D.; Balard, Philippe; Stadler, Eric; Guillaume, Christian; Boutolleau, David; Coussement, Jérome; Kolb, Johann; Hubin, Norbert; Derelle, Sophie; Robert, Clélia; Tanchon, Julien; Trollier, Thierry; Ravex, Alain; Zins, Gérard; Kern, Pierre; Moulin, Thibaut; Rochat, Sylvain; Delpoulbé, Alain; Lebouqun, Jean-Baptiste

    2014-07-01

    cooled device without liquid nitrogen in very demanding environmental conditions. A successful test of this device was performed on sky on the PIONIER 4 telescopes beam combiner on the VLTi at ESOParanal in June 2014. First Light Imaging, which will commercialize a camera system using also APD infrared arrays in its proprietary wavefront sensor camera platform. These programs are held with several partners, among them are the French astronomical laboratories (LAM, OHP, IPAG), the detector manufacturers (e2v technologies, Sofradir, CEA/LETI) and other partners (ESO, ONERA, IAC, GTC, First Light Imaging). Funding is: Opticon FP7 from European Commission, ESO, CNRS and Université de Provence, Sofradir, ONERA, CEA/LETI the French FUI (DGCIS), the FOCUS Labex and OSEO.

  4. The Virtual Astronomical Observatory: Re-engineering access to astronomical data

    Science.gov (United States)

    Hanisch, R. J.; Berriman, G. B.; Lazio, T. J. W.; Emery Bunn, S.; Evans, J.; McGlynn, T. A.; Plante, R.

    2015-06-01

    The US Virtual Astronomical Observatory was a software infrastructure and development project designed both to begin the establishment of an operational Virtual Observatory (VO) and to provide the US coordination with the international VO effort. The concept of the VO is to provide the means by which an astronomer is able to discover, access, and process data seamlessly, regardless of its physical location. This paper describes the origins of the VAO, including the predecessor efforts within the US National Virtual Observatory, and summarizes its main accomplishments. These accomplishments include the development of both scripting toolkits that allow scientists to incorporate VO data directly into their reduction and analysis environments and high-level science applications for data discovery, integration, analysis, and catalog cross-comparison. Working with the international community, and based on the experience from the software development, the VAO was a major contributor to international standards within the International Virtual Observatory Alliance. The VAO also demonstrated how an operational virtual observatory could be deployed, providing a robust operational environment in which VO services worldwide were routinely checked for aliveness and compliance with international standards. Finally, the VAO engaged in community outreach, developing a comprehensive web site with on-line tutorials, announcements, links to both US and internationally developed tools and services, and exhibits and hands-on training at annual meetings of the American Astronomical Society and through summer schools and community days. All digital products of the VAO Project, including software, documentation, and tutorials, are stored in a repository for community access. The enduring legacy of the VAO is an increasing expectation that new telescopes and facilities incorporate VO capabilities during the design of their data management systems.

  5. Ground-Based High Energy Power Beaming in Support of Spacecraft Power Requirements

    Science.gov (United States)

    2006-06-01

    spending a hot day at the beach on anything that was to pass xxv into the beam. Further more, the beam will be invisible to the naked eye as it is...other galaxies for probing cosmology . As such, the multibeam system will have a broad appeal to astronomers from all over the world.34 d. ChAOS The

  6. The Double Didactic Astronomical Quadrant for the XIII International Astronomical Olympiad

    CERN Document Server

    Maris, Michele; Boehm, Conrad; Iafrate, Giulia; Ramella, Massimo

    2010-01-01

    Here we present the development of a simplified version of double astronomical quadrant, designed for educational aims and realized on the occasion of the observational round of the XIII International Astronomy Olympiad, held in Trieste (Italy) October 13-21, 2008. (Italia: In questo contributo illustriamo il progetto di una versione semplificata di doppio quadrante astronomico, progettato per fini didattici e realizzato in occasione dello svolgimento della gara osservativa delle XIII Olimpiadi Internazionali di Astronomia (XIII International Astronomy Olympiad, XIII IAO), Trieste (I), 13-21 ottobre 2008))

  7. An Astronomer In The Classroom: Observatoire de Paris's Partnership Between Teachers and Astronomers

    Science.gov (United States)

    Doressoundiram, A.; Barban, C.

    2006-08-01

    The Observatoire de Paris is offering a partnership between teachers and astronomers. The principle is simple: any teacher wishing to undertake a pedagogical project in astronomy, in the classroom or involving the entire school, can request the help of a mentor. An astronomer from the Observatoire de Paris will then follow the teacher's project progress and offer advice and scientific support throughout the school year. The projects may take different forms: construction projects (models, instruments), lectures, posters, exhibitions, etc. The type of assistance offered is as varied as the projects: lecture(s) in class, telephone and e-mail exchanges, visits to the Observatoire; an almost made-to-measure approach that delighted the thirty or so groups that benefited such partnership in the 2005-2006 academic year. And this number is continuously growing. There was a rich variety of projects undertaken, from mounting a show and building a solar clock to visiting a high altitude observatory, or resolving the mystery of Jupiter's great red spot. The Universe and its mysteries fascinate the young (and the not so- young) and provide a multitude of scientific topics that can be exploited in class. Astronomy offers the added advantage of being a multidisciplinary field. Thus, if most projects are generally initiated by a motivated teacher, they are often taken over by teachers in other subjects: Life and Earth Sciences (SVT), history, mathematics, French, and so forth. The project may consist in an astronomy workshop or be part of the school curriculum. Whatever the case, the astronomer's task is not to replace the teacher or the textbooks, but to propose activities or experiments that are easy to implement. Representing the Solar system on a school-yard scale, for instance, is a perfect way to make youngsters realize that the Universe consists mostly of empty space. There is no shortage of topics, and the students' enthusiasm, seldom absent, is the best reward for the

  8. Detection and removal of artifacts in astronomical images

    Science.gov (United States)

    Desai, S.; Mohr, J. J.; Bertin, E.; Kümmel, M.; Wetzstein, M.

    2016-07-01

    Astronomical images from optical photometric surveys are typically contaminated with transient artifacts such as cosmic rays, satellite trails and scattered light. We have developed and tested an algorithm that removes these artifacts using a deep, artifact free, static sky coadd image built up through the median combination of point spread function (PSF) homogenized, overlapping single epoch images. Transient artifacts are detected and masked in each single epoch image through comparison with an artifact free, PSF-matched simulated image that is constructed using the PSF-corrected, model fitting catalog from the artifact free coadd image together with the position variable PSF model of the single epoch image. This approach works well not only for cleaning single epoch images with worse seeing than the PSF homogenized coadd, but also the traditionally much more challenging problem of cleaning single epoch images with better seeing. In addition to masking transient artifacts, we have developed an interpolation approach that uses the local PSF and performs well in removing artifacts whose widths are smaller than the PSF full width at half maximum, including cosmic rays, the peaks of saturated stars and bleed trails. We have tested this algorithm on Dark Energy Survey Science Verification data and present performance metrics. More generally, our algorithm can be applied to any survey which images the same part of the sky multiple times.

  9. Spectroscopy for amateur astronomers recording, processing, analysis and interpretation

    CERN Document Server

    Trypsteen , Marc F M

    2017-01-01

    This accessible guide presents the astrophysical concepts behind astronomical spectroscopy, covering both the theory and the practical elements of recording, processing, analysing and interpreting your spectra. It covers astronomical objects, such as stars, planets, nebulae, novae, supernovae, and events such as eclipses and comet passages. Suitable for anyone with only a little background knowledge and access to amateur-level equipment, the guide's many illustrations, sketches and figures will help you understand and practise this scientifically important and growing field of amateur astronomy, up to the level of Pro-Am collaborations. Accessible to non-academics, it benefits many groups from novices and learners in astronomy clubs, to advanced students and teachers of astrophysics. This volume is the perfect companion to the Spectral Atlas for Amateur Astronomers, which provides detailed commented spectral profiles of more than 100 astronomical objects.

  10. The application of interferometry to optical astronomical imaging.

    Science.gov (United States)

    Baldwin, John E; Haniff, Christopher A

    2002-05-15

    In the first part of this review we survey the role optical/infrared interferometry now plays in ground-based astronomy. We discuss in turn the origins of astronomical interferometry, the motivation for its development, the techniques of its implementation, examples of its astronomical significance, and the limitations of the current generation of interferometric arrays. The second part focuses on the prospects for ground-based astronomical imaging interferometry over the near to mid-term (i.e. 10 years) at optical and near-infrared wavelengths. An assessment is made of the astronomical and technical factors which determine the optimal designs for imaging arrays. An analysis based on scientific capability, technical feasibility and cost argues for an array of large numbers of moderate-sized (2 m class) telescopes rather than one comprising a small number of much larger collectors.

  11. Lessons from the masters current concepts in astronomical image processing

    CERN Document Server

    2013-01-01

    There are currently thousands of amateur astronomers around the world engaged in astrophotography at increasingly sophisticated levels. Their ranks far outnumber professional astronomers doing the same and their contributions both technically and artistically are the dominant drivers of progress in the field today. This book is a unique collaboration of individuals, all world-renowned in their particular area, and covers in detail each of the major sub-disciplines of astrophotography. This approach offers the reader the greatest opportunity to learn the most current information and the latest techniques directly from the foremost innovators in the field today.   The book as a whole covers all types of astronomical image processing, including processing of eclipses and solar phenomena, extracting detail from deep-sky, planetary, and widefield images, and offers solutions to some of the most challenging and vexing problems in astronomical image processing. Recognized chapter authors include deep sky experts su...

  12. Astronomical sketching a step-by-step introduction

    CERN Document Server

    Handy, Richard; Perez, Jeremy; Rix, Erika; Robbins, Sol

    2007-01-01

    This book presents the amateur with fine examples of astronomical sketches and step-by-step tutorials in each medium, from pencil to computer graphics programs. This unique book can teach almost anyone to create beautiful sketches of celestial objects.

  13. PPARC: Grid technology helps astronomers keep pace with the Universe

    CERN Multimedia

    2003-01-01

    "Intelligent Agent" computer programs are roaming the Internet and watching the skies. These programs, using Grid computing technology, will help astronomers detect some of the most dramatic events in the universe, such as massive supernova explosions (1 page).

  14. Reliability centered maintenance in astronomical infrastructure facilities

    Science.gov (United States)

    Ansorge, W. R.

    2006-06-01

    Hundreds of mirror segment, thousands of high precision actuators, highly complex mechanical, hydraulic, electrical and other technology subsystems, and highly sophisticated control systems: an ELT system consists of millions of individual parts and components, each of them may fail and lead to a partial or complete system breakdown. The traditional maintenance concepts characterized by predefined preventive maintenance activities and rigid schedules are not suitable for handling this large number of potential failures and malfunctions and the extreme maintenance workload. New maintenance strategies have to be found suitable to increase reliability while reducing the cost of needless maintenance services. The Reliability Centred Maintenance (RCM) methodology is already used extensively by airlines, and in industrial and marine facilities and even by scientific institutions like NASA. Its application increases the operational reliability while reducing the cost of unnecessary maintenance activities and is certainly also a solution for current and future ELT facilities. RCM is a concept of developing a maintenance scheme based on the reliability of the various components of a system by using "feedback loops between instrument / system performance monitoring and preventive/corrective maintenance cycles." Ideally RCM has to be designed within a system and should be located in the requirement definition, the preliminary and final design phases of new equipment and complicated systems. However, under certain conditions, an implementation of RCM into the maintenance management strategy of already existing astronomical infrastructure facilities is also possible. This presentation outlines the principles of the RCM methodology, explains the advantages, and highlights necessary changes in the observatory development, operation and maintenance philosophies. Presently, it is the right time to implement RCM into current and future ELT projects and to save up to 50% maintenance

  15. Preservation and maintenance of the astronomical sites in Armenia

    Science.gov (United States)

    Mickaelian, A. M.

    2008-01-01

    Astronomy in Armenia was popular since ancient times. There are signs of astronomical observations coming from a few thousands years ago. Two ancient observatories, Karahunge and Metzamor are especially well known. Karahunge is the Armenian twin of the Stonehenge and is even older. However, there is no proper attention from the state authorities and efforts are needed for preservation of such historical-astronomical monuments. The Byurakan Astrophysical Observatory (BAO) is the modern famous Armenian observatory founded in 1946 by the outstanding scientist Victor Ambartsumian. It was one of the world astronomical centres in 1950-s to 1970-s, and at present is the largest observatory in the Middle East area. As the ancient astronomical sites, Byurakan also needs a proper attitude from the state authorities and corresponding international organizations to preserve its values and importance for the present and future astronomical activities in the region, including its rich observational archive, telescopes, and human resources. Despite all the difficulties, the Armenian astronomers keep high international level of research and display various activities organizing international meetings and schools, preparing new young generation for the future research. The Armenian Astronomical Society (ArAS) is an affiliated member of EAS. Armenia has its Virtual Observatory project (ArVO) as well. The next Joint European and National Astronomy Meeting (JENAM-2007) will be held in Yerevan, Armenia, in August 2007. There are plans to organize astronomical tours to Armenia for making observations from various sites, including the ancient observatories. The future of astronomy in Armenia strongly depends on all of this activities and the proper attention both from state authorities and society.

  16. Applying artificial intelligence to astronomical databases - a surveyof applicable technology.

    Science.gov (United States)

    Rosenthal, D. A.

    This paper surveys several emerging technologies which are relevant to astronomical database issues such as interface technology, internal database representation, and intelligent data reduction aids. Among the technologies discussed are natural language understanding, frame and object representations, planning, pattern analysis, machine learning and the nascent study of simulated neural nets. These techniques will become increasingly important for astronomical research, and in particular, for applications with large databases.

  17. Astronomical guidance for directed searches for continuous gravitational waves

    Science.gov (United States)

    Owen, Benjamin

    2014-01-01

    The LIGO Scientic Collaboration and Virgo Collaboration have published a search for continuous gravitational-waves from the non-pulsing neutron star in supernova remnant Cas A and, more recently, from the galactic center. More such searches, where the direction is known but no pulsar timing is available, are under way. I describe the astronomical criteria for good targets for such gravitational-wave searches, list classes of astronomical objects, and give examples of each class.

  18. Astronomers watch the stars come out in berkeley.

    Science.gov (United States)

    1993-06-25

    New and strange sightings caught the attention of astronomers at this June's American Astronomical Society (AAS) meeting in Berkeley: a supernova that has changed its identity, a clutch of mysterious blue stars, and objects at the edge of the universe, shining brilliantly at the far end of the ultraviolet spectrum. Meanwhile, a more familiar object-one species of supernova-is raising hopes of predicting the ultimate fate of this cosmic zoo.

  19. Blowing bubbles in the cosmos astronomical winds, jets, and explosions

    CERN Document Server

    Hartquist, T W; Ruffle, D P

    2004-01-01

    1. The First Discoveries of Astronomical Winds2. The Magnitudes of Astronomical Quantities3. Stellar Evolution4. Basic Structures of Winds and Windblown Bubbles5. Star Formation and Low-Mass Young Stellar Objects6. Regions of High-Mass Star Formation7. Winds from Main-Sequence and Post-Main-Sequence Stars8. Supernovae and Their Remnants9. Galactic Winds, Starburst Superwinds, and the Epoch of Galaxy Formation10. Active Galaxies and Their Nuclei11. Some Other Windy and Explosive Sources

  20. Evaluation of a combined respiratory-gating system comprising the TrueBeam linear accelerator and a new real-time tumor-tracking radiotherapy system: a preliminary study.

    Science.gov (United States)

    Shiinoki, Takehiro; Kawamura, Shinji; Uehara, Takuya; Yuasa, Yuki; Fujimoto, Koya; Koike, Masahiro; Sera, Tatsuhiro; Emoto, Yuki; Hanazawa, Hideki; Shibuya, Keiko

    2016-07-08

    A combined system comprising the TrueBeam linear accelerator and a new real-time, tumor-tracking radiotherapy system, SyncTraX, was installed in our institution. The goals of this study were to assess the capability of SyncTraX in measuring the position of a fiducial marker using color fluoroscopic images, and to evaluate the dosimetric and geometric accuracy of respiratory-gated radiotherapy using this combined system for the simple geometry. For the fundamental evaluation of respiratory-gated radiotherapy using SyncTraX, the following were performed:1) determination of dosimetric and positional characteristics of sinusoidal patterns using a motor-driven base for several gating windows; 2) measurement of time delay using an oscilloscope; 3) positional verification of sinusoidal patterns and the pattern in the case of a lung cancer patient; 4) measurement of the half-value layer (HVL in mm AL), effective kVp, and air kerma, using a solid-state detector for each fluoroscopic condition, to determine the patient dose. The dose profile in a moving phantom with gated radiotherapy having a gating window ≤ 4 mm was in good agreement with that under static conditions for each photon beam. The total time delay between TrueBeam and SyncTraX was system comprising TrueBeam and SyncTraX could track the motion of the fiducial marker and control radiation delivery with reasonable accuracy; therefore, this system provides significant dosimetric improvement. However, patient exposure dose from fluoroscopy was not clinically negligible. © 2016 The Authors.

  1. Modelling MEMS deformable mirrors for astronomical adaptive optics

    Science.gov (United States)

    Blain, Celia

    As of July 2012, 777 exoplanets have been discovered utilizing mainly indirect detection techniques. The direct imaging of exoplanets is the next goal for astronomers, because it will reveal the diversity of planets and planetary systems, and will give access to the exoplanet's chemical composition via spectroscopy. With this spectroscopic knowledge, astronomers will be able to know, if a planet is terrestrial and, possibly, even find evidence of life. With so much potential, this branch of astronomy has also captivated the general public attention. The direct imaging of exoplanets remains a challenging task, due to (i) the extremely high contrast between the parent star and the orbiting exoplanet and (ii) their small angular separation. For ground-based observatories, this task is made even more difficult, due to the presence of atmospheric turbulence. High Contrast Imaging (HCI) instruments have been designed to meet this challenge. HCI instruments are usually composed of a coronagraph coupled with the full onaxis corrective capability of an Extreme Adaptive Optics (ExAO) system. An efficient coronagraph separates the faint planet's light from the much brighter starlight, but the dynamic boiling speckles, created by the stellar image, make exoplanet detection impossible without the help of a wavefront correction device. The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system is a high performance HCI instrument developed at Subaru Telescope. The wavefront control system of SCExAO consists of three wavefront sensors (WFS) coupled with a 1024- actuator Micro-Electro-Mechanical-System (MEMS) deformable mirror (DM). MEMS DMs offer a large actuator density, allowing high count DMs to be deployed in small size beams. Therefore, MEMS DMs are an attractive technology for Adaptive Optics (AO) systems and are particularly well suited for HCI instruments employing ExAO technologies. SCExAO uses coherent light modulation in the focal plane introduced by the DM, for

  2. The Expansion of the Astronomical Photographic Data Archive at PARI

    Science.gov (United States)

    Cline, J. Donald; Barker, Thurburn; Castelaz, Michael

    2017-01-01

    A diverse set of photometric, astrometric, spectral and surface brightness data exist on decades of photographic glass plates. The Astronomical Photographic Data Archive (APDA) at the Pisgah Astronomical Research Institute (PARI) was established in November 2007 and is dedicated to the task of collecting, restoring, preserving and storing astronomical photographic data and PARI continues to accept collections. APDA is also tasked with scanning each image and establishing a database of images that can be accessed via the Internet by the global community of scientists, researchers and students. APDA is a new type of astronomical observatory - one that harnesses analog data of the night sky taken for more than a century and making that data available in a digital format.In 2016, APDA expanded from 50 collections with about 220,000 plates to more than 55 collections and more than 340,000 plates and films. These account for more than 30% of all astronomical photographic data in the United States. The largest of the new acquisitions are the astronomical photographic plates in the Yale University collection. We present details of the newly added collections and review of other collections in APDA.

  3. Novel gratings for next-generation instruments of astronomical observations

    Science.gov (United States)

    Ebizuka, N.; Okamoto, T.; Takeda, M.; Hosobata, T.; Yamagata, Y.; Sasaki, M.; Uomoto, M.; Shimatsu, T.; Sato, S.; Hashimoto, N.; Tanaka, I.; Hattori, T.; Ozaki, S.; Aoki, W.

    2017-05-01

    We will introduce current status of development of a birefringence volume phase holographic (B-VPH) grating, volume binary (VB) grating and reflector facet transmission (RFT) grating developing as the novel dispersive optical element for astronomical instruments for the 8.2m Subaru Telescope, for next generation 30 m class huge ground-based telescopes and for next generation large space-bone telescopes. We will also introduce a hybrid grism developed for MOIRCS (Multi-Object InfraRed Camera and Spectrograph) of the Subaru Telescope and a quasi-Bragg (QB) immersion grating. Test fabrication of B-VPH gratings with a liquid crystal (LC) of UV curable and normal LCs or a resin of visible light curable are performed. We successfully fabricated VB gratings of silicon as a mold with ridges of a high aspect ratio by means of the cycle etching process, oxidation and removal of silicon oxide. The RFT grating which is a surface-relief (SR) transmission grating with sawtooth shaped ridges of an acute vertex angle. The hybrid grism, as a prototype of the RFT grating, combines a high-index prism and SR transmission grating with sawtooth shape ridges of an acute vertex angle. The mold of the SR grating for the hybrid grism on to a work of Ni-P alloy of non-electrolysic plating successfully fabricated by using our ultra-precision machine and a single-crystal diamond bite. The QB immersion grating was fabricated by a combination of an inclined QB grating, Littrow prism and surface reflection mirror.

  4. SPHEREx: Science Opportunities for the Astronomical Community

    Science.gov (United States)

    Cooray, Asantha; SPHEREx Science Team

    2018-01-01

    SPHEREx, a mission in NASA's Medium Explorer (MIDEX) program that was selected for Phase A study in August 2017, will perform an all-sky near-infrared spectral survey between 0.75 - 5.0 microns. The survey will reach 18.3 AB mag (5 sigma) in R=41 filters, with R=135 coverage between 4.2 - 5.0 microns. The key science topics of the SPHEREx team are: (a) primordial non-Gaussianity through 3-dimensional galaxy clustering; (b) extragalactic background light fluctuations; and (c) ices and biogenic molecules in the interstellar medium and towards protoplanetary environments.The large legacy dataset of SPHEREx will enable a large number of scientific studies and find interesting targets for follow-up observations with Hubble, JWST, ALMA, among other facilities. The SPHEREx catalog will include 1.4 billion galaxies, with redshifts secured for more than 10 and 120 million with fractional accuracies in error/(1+z) better than 0.3% and 3%, respectively. The spectral coverage and resolution provided by SPHEREx are adequate to determine redshifts for most WISE-detected sources with an accuracy better than 3%. The catalog will contain close to 1.5 million quasars including 300 bright QSOs at z > 7 during the epoch of reionization, based on observational extrapolations. The catalog will be adequate to obtain redshifts for all 25,000 galaxy clusters expected to be detected in X-rays with e-Rosita. SPHEREx produces all-sky maps of the Galactic emission lines, including hydrocarbon emission around 3 microns.In this poster, we will show example science studies the broader astronomical community will be able to lead using the SPHEREx database. We will also outline existing plans within the SPHEREx team to develop software tools to enable easy access to the data and to conduct catalog searches, and ways in which the community can provide input to the SPHEREx Science Team on scientific studies and data/software requirements for those studies. The team is eager to develop best software

  5. Beam Dynamics

    CERN Document Server

    Wilson, E

    2013-01-01

    This document is part of Subvolume C 'Accelerators and Colliders' of Volume 21 'Elementary Particles' of Landolt-Börnstein - Group I 'Elementary Particles, Nuclei and Atoms'. It contains the Chapter '2 Beam Dynamics' with the content: 2 Beam Dynamics 2.1 Linear Transverse Beam Dynamics 2.2 Coupling 2.3 Liouville's Theorem 2.4 Momentum Dependent Transverse Motion 2.5 Longitudinal Motion

  6. Phase II Trial of Combined High Dose Rate Brachytherapy and External Beam Radiotherapy for Adenocarcinoma of the Prostate: Preliminary Results of RTOG 0321

    Science.gov (United States)

    Hsu, I-Chow; Bae, Kyounghwa; Shinohara, Katsuto; Pouliot, Jean; Purdy, James; Ibbott, Geoffrey; Speight, Joycelyn; Vigneault, Eric; Ivker, Robert; Sandler, Howard

    2010-01-01

    Purpose To estimate the rate of late grade 3 or greater genitourinary (GU) and gastrointestinal (GI) adverse events (AEs) following treatment with external beam radiation therapy and prostate high dose rate (HDR) brachytherapy. Methods and Materials Each participating institution submitted CT based HDR brachytherapy dosimetry data electronically for credentialing and for each study patient. Patients with locally confined T1c-T3b prostate cancer were eligible for this study. All patients were treated with 45 Gy in 25 fractions from external beam radiotherapy and one HDR implant delivering 19 Gy in 2 fractions. All AEs were graded according to CTCAEv3.0. Late GU/ GI AEs were defined as those occurring more than nine months from the start of the protocol treatment, in patients with at least 18 months of potential follow-up. Results A total of 129 patients from 14 institutions were enrolled in this study. 125 patients were eligible and AE data was available for 112 patients. The pretreatment characteristics of the patients were as follows: T1c-T2c 91%, T3a-T3b 9%, PSA ≤ 10 70%, PSA >10-≤20 30%, GS 2-6 10%, GS 7 72%, and GS 8-10 18%. At a median follow-up time of 29.6 months, 3 acute and 4 late grade 3 GU/GI AEs were reported. The estimated rate of late grade 3-5 GU and GI AE at 18 months was 2.56%. Conclusion This is the first prospective, multi-institutional trial of CT based HDR brachytherapy and external beam radiotherapy. The technique and doses used in this study resulted in acceptable levels of adverse events. PMID:20207506

  7. Recollections of life as a student and a young astronomer in Germany in the 1920s

    Science.gov (United States)

    Brück, Hermann A.; Brück, Mary T.

    2000-12-01

    The author of this essay, Hermann Alexander Brück, Emeritus Professor of Astronomy at the University of Edinburgh and former Astronomer Royal for Scotland, died on 4 March 2000 in his 95th year. He was the last of his generation of astronomers in both Germany and Britain, and among the oldest members, if not the oldest, of the Royal Astronomical Society and of the Astronomische Gesellschaft. Hermann Brück was born in Berlin in 1905 and, as he recounts below, received his education at the Universities of Kiel, Bonn and Munich in 1924-1928. To the end of his life he looked back on his student days in Munich as the most profitable and exciting he ever experienced. From Munich he began his astronomical career at the Potsdam Astrophysical Observatory. These, too, were happy days, destined, however, to be blighted within a few years by the rise of Nazism. In 1936 Brück left Germany, and obtained a temporary Research Assistantship at the Vatican Observatory. From there he went a year later to Cambridge, rising to the rank of John Couch Adams Astronomer and Assistant Director of the Observatory. In 1947, in response to an invitation from Eamon de Valera, then Taoiseach (Prime Minister) of Ireland, he moved to Dublin where he undertook the task of re-founding the defunct Dunsink Observatory under the auspices of the Dublin Institute for Advanced Studies. He moved from Dublin to the Royal Observatory Edinburgh in 1957, taking up the combined post of Astronomer Royal for Scotland and Regius Professor of Astronomy in the University of Edinburgh. He retired in 1975 at the age of 70. Always interested in history, he occupied himself in his retirement with various historical projects. These included writing the histories of the Royal Observatory Edinburgh (The Story of Astronomy in Edinburgh, Edinburgh 1983) and of the earlier Dun Echt Observatory in Aberdeenshire (Lord Crawford's Observatory at Dun Echt 1872-1892, Vistas in Astronomy 35, 1992) as well as a record of his own

  8. Long-Term Results of an RTOG Phase II Trial (00-19) of External-Beam Radiation Therapy Combined With Permanent Source Brachytherapy for Intermediate-Risk Clinically Localized Adenocarcinoma of the Prostate

    Energy Technology Data Exchange (ETDEWEB)

    Lawton, Colleen A., E-mail: clawton@mcw.edu [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI (United States); Yan, Yan [Radiation Therapy Oncology Group Statistical Center, Philadelphia, PA (United States); Lee, W. Robert [Department of Radiation Oncology, Duke University School of Medicine, Durham, NC (United States); Gillin, Michael [Department of Radiation Oncology, MD Anderson Cancer Center, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Firat, Selim [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI (United States); Baikadi, Madhava [Department of Radiation Oncology, Northeast Radiation Oncology Center, Scranton, PA (United States); Crook, Juanita [Department of Radiation Oncology, University of British Columbia, Kelowna, BC (Canada); Kuettel, Michael [Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, NY (United States); Morton, Gerald [Department of Radiation Oncology, Toronto-Sunnybrook Regional Cancer Center, Toronto, ON (Canada); Sandler, Howard [Department of Radiation Oncology, Cedars-Sinai Medical Center, Los Angeles, CA (United States)

    2012-04-01

    Purpose: External-beam radiation therapy combined with low-doserate permanent brachytherapy are commonly used to treat men with localized prostate cancer. This Phase II trial was performed to document late gastrointestinal or genitourinary toxicity as well as biochemical control for this treatment in a multi-institutional cooperative group setting. This report defines the long-term results of this trial. Methods and Materials: All eligible patients received external-beam radiation (45 Gy in 25 fractions) followed 2-6 weeks later by a permanent iodine 125 implant of 108 Gy. Late toxicity was defined by the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer late radiation morbidity scoring scheme. Biochemical control was defined by the American Society for Therapeutic Radiology and Oncology (ASTRO) Consensus definition and the ASTRO Phoenix definition. Results: One hundred thirty-eight patients were enrolled from 20 institutions, and 131 were eligible. Median follow-up (living patients) was 8.2 years (range, 2.7-9.3 years). The 8-year estimate of late grade >3 genitourinary and/or gastrointestinal toxicity was 15%. The most common grade >3 toxicities were urinary frequency, dysuria, and proctitis. There were two grade 4 toxicities, both bladder necrosis, and no grade 5 toxicities. In addition, 42% of patients complained of grade 3 impotence (no erections) at 8 years. The 8-year estimate of biochemical failure was 18% and 21% by the Phoenix and ASTRO consensus definitions, respectively. Conclusion: Biochemical control for this treatment seems durable with 8 years of follow-up and is similar to high-dose external beam radiation alone or brachytherapy alone. Late toxicity in this multi-institutional trial is higher than reports from similar cohorts of patients treated with high-dose external-beam radiation alone or permanent low-doserate brachytherapy alone, perhaps suggesting further attention to strategies that limit doses to

  9. The Sensitization of French Observatory Directors to Astronomical Heritage

    Science.gov (United States)

    Le Guet Tully, Françoise; Davoigneau, Jean

    2012-09-01

    An inventory of the heritage of historical astronomical observatories was launched in the mid 1990s as part of a collaboration between the Ministry of Research and the Ministry of Culture. This has produced a significant body of knowledge not only on astronomical instruments, but also on the specificities of astronomical sites and on the architecture of observatories. Other major results of this operation are (i) the development of numerous works on the institutional history of observatories and (ii), at the request of a few directors, the protection as "historical monuments" of some buildings and of collections of instruments. Given that knowledge about astronomical heritage is a prerequisite for proper conservation and intelligent outreach, and given also that the protection of such heritage (as historical monuments) is a major asset that bolsters its cultural value, the long term sustainability of such heritage depends on political decisions and the search for financial support. We shall describe the complex administrative situation of French observatories and outline the various actions undertaken recently to sensitize their directors to astronomical heritage issues.

  10. Analysis of Korean astronomical records with Chinese equatorial coordinates

    Science.gov (United States)

    Lee, K. W.

    2012-08-01

    The historical documents of ancient Korea contain abundant records on various astronomical phenomena. The historical documents of the Joseon dynasty contain observational values based on Chinese equatorial coordinate system (i.e., angular distances from the reference star of a lunar mansion and the North Pole). However, quantitative analysis of the observational values has not been carried out. In this study, we investigate the observational accuracy during the Joseon dynasty by comparing the astronomical records of Joseonwangjo Sillok (Annals of the Joseon Dynasty) and Seungjeongwon Ilgi (Daily Records of the Royal Secretariat) with modern astronomical calculations. Consequently, we find that the observational accuracy during the early Joseon dynasty was approximately 1.2° 0.3° in the right ascension and declination, respectively. On the other hand, we find that the observational accuracy during the later Joseon dynasty was considerably poor. Observations of Halley's comet in 1759 were off by approximately 7° in declination. We believe that further investigation is required to verify the reason for this poor accuracy. Thus, we list the complete records used for this study in the appendix. We believe that these records also can contribute to modern studies on phenomena such as supernovae or Halley's comet. In conclusion, we believe that this study is useful for understanding ancient Korean astronomical records, even though we have considered a small number of astronomical events.

  11. Beam diagnostics

    CERN Document Server

    Raich, U

    2006-01-01

    The instrumentation measuring beam parameters constitutes an important part of any particle accelerator. These lectures aim at giving an overview of detection and measurement techniques without going too much into details of implementation. Instruments for linear accelerators, transfer lines, and small synchrotrons are described with an emphasis on opportunities and problems specific to low-energy particle beams.

  12. NETWORK CODING BY BEAM FORMING

    DEFF Research Database (Denmark)

    2013-01-01

    Network coding by beam forming in networks, for example, in single frequency networks, can provide aid in increasing spectral efficiency. When network coding by beam forming and user cooperation are combined, spectral efficiency gains may be achieved. According to certain embodiments, a method...

  13. Concept of the solar-pumped laser-photovoltaics combined system and its application to laser beam power feeding to electric vehicles

    Science.gov (United States)

    Motohiro, Tomoyoshi; Takeda, Yasuhiko; Ito, Hiroshi; Hasegawa, Kazuo; Ikesue, Akio; Ichikawa, Tadashi; Higuchi, Kazuo; Ichiki, Akihisa; Mizuno, Shintaro; Ito, Tadashi; Yamada, Noboru; Nath Luitel, Hom; Kajino, Tsutomu; Terazawa, Hidetaka; Takimoto, Satoshi; Watanabe, Kemmei

    2017-08-01

    We have developed a compact solar-pumped laser (µSPL) employing an off-axis parabolic mirror with an aperture of 76.2 mm diameter and an yttrium aluminum garnet (YAG) ceramic rod of φ1 mm × 10 mm doped with 1% Nd and 0.1% Cr as a laser medium. The laser oscillation wavelength of 1.06 µm, just below the optical absorption edge of Si cells, is suitable for photoelectric conversion with minimal thermal loss. The concept of laser beam power feeding to an electric vehicle equipped with a photovoltaic panel on the roof was proposed by Ueda in 2010, in which the electricity generated by solar panels over the road is utilized to drive a semiconductor laser located on each traffic signal along the road. By substituting this solar-electricity-driven semiconductor laser with a solar-pumped laser, the energy loss of over 50% in converting the solar electricity to a laser beam can be eliminated. The overall feasibility of this system in an urban area such as Tokyo was investigated.

  14. 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.

  15. Ashra Neutrino Telescope Array (NTA): Combined Imaging Observation of Astroparticles — For Clear Identification of Cosmic Accelerators and Fundamental Physics Using Cosmic Beams

    Science.gov (United States)

    Sasaki, Makoto; Kifune, Tadashi

    In VHEPA (very high energy particle astronomy) 2014 workshop, focused on the next generation explorers for the origin of cosmic rays, held in Kashiwa, Japan, reviewing and discussions were presented on the status of the observation of GeV-TeV photons, TeV-PeV neutrinos, EeV-ZeV hadrons, test of interaction models with Large Hadron Collider (LHC), and theoretical aspects of astrophysics. The acceleration sites of hadrons, i.e., sources of PeV-EeV cosmic rays, should exist in the universe within the GZK-horizon even in the remotest case. We also affirmed that the hadron acceleration mechanism correlates with cosmic ray composition so that it is important to investigate the acceleration mechanism in relevance to the composition survey at PeV-EeV energy. We regard that LHC and astrophysics theories are ready to be used to probe into hadron acceleration mechanism in the universe. Recently, IceCube has reported detection of three events of neutrinos with energies around 1 PeV and additional events at lower energies, which significantly deviate from the expected level of background events. It is necessary to observe GeV-TeV photon, EeV-ZeV hadron and TeV-PeV neutrino all together, in order to understand hadronic interactions of cosmic rays in the PeV-EeV energy region. It is required to make a step further toward exploring the PeV-EeV universe with high accuracy and high statistics observations for both neutrinos and gamma rays simultaneously, by using the instrument such as Ashra Neutrino Telescope Array (NTA). Wide and fine survey of gamma-rays and neutrinos with simultaneously detecting Cherenkov and fluorescence light with NTA will guide us to a new intriguing stage of recognizing astronomical objects and non-thermal phenomena in ultra-high energy region, in addition, new aspect about the fundamental concepts of physics beyond our presently limited understanding; the longstanding problem of cosmic ray origin, the radiation mechanism of gamma-rays, neutrino and

  16. The Church of San Miniato al Monte, Florence: Astronomical and Astrological Connections

    Science.gov (United States)

    Shrimplin, V.

    2011-06-01

    The church of San Miniato al Monte is examined in the context of interest in astrology and astronomy in early Renaissance Florence. Vitruvius emphasised the need for architects to "be acquainted with astronomy and the theory of the heavens" in his famous Ten Books of Architecture and, at San Miniato, astronomical and astrological features are combined in order to link humanity with the celestial or spiritual realm. The particular significance of Pisces and Taurus is explored in relation to Christian symbolism, raising questions about the role of astronomy and astrology in art and architecture.

  17. Teaching astronomical navigation at the university: an historical overview

    Science.gov (United States)

    López Varela, P.; Salgado Don, A.; Manteiga Outeiro, M.

    2011-11-01

    Astronomy and navigation are two sciences whose historical evolution have been linked for centuries through relationships of mutual dependency, up to the point of leading to a new science: astronomical or celestial navigation. Currently, astronomy has a very important well defined area within all university nautical degrees. Knowledge of astronomical navigation is still mandatory for deck officers in merchant ships. In the GPS era, practicing astronomical navigation has been relegated to a mere control procedure, and the tendency is to falling into disuse. Nevertheless, it is still the only method through which seamen can depend on their own means and knowledge to keep a track in a safe way. The new syllabi of our majors contemplates a drastic reduction of the contents of this subject, whose importance in the seafarer's profession we want to highlight in this paper.

  18. The Astronomer Alexander I. Postoiev (1900-1976)

    Science.gov (United States)

    Dos Santos, P. M.; Matsuura, O. T.

    This is a biographical note on the life of Dr Alexander I. Postoiev, a victim of Stalin's purge of Soviet astronomers in 1936-1937 (McCutcheon, 1985). Along with his family, he left the Soviet Union in 1943, and lived in Germany as a refugee and "displaced person" until 1952, when he moved to Brazil. Then he started the second part of his professional career. Thanks to his efforts the Astronomical and Geophysical Institute (IAG) from the University of Sao Paulo (USP) was involved, for the first time, in programme of international cooperation, thus contributing to the institutional consolidation of IAG/USP as a leading centre of astronomical research and teaching today in Brazil.

  19. Profiling Some of the Lesser-Known Historical Women Astronomers

    Science.gov (United States)

    Pagnotta, Ashley

    2016-01-01

    Although some historical women astronomers such as Henrietta Swan Leavitt and Cecilia Payne Gaposchkin have recently become somewhat well known among the astronomical community, many others--especially those from non-Western cultures--remain a mystery even to those of us who are actively aware of and interested in the role of early women in astronomy. As part of a project to educate myself on some of these women, I started a blog series (http://ashpags.tumblr.com/tagged/lady-astronomers) to share this newfound knowledge with a population that is on average relatively young, extremely tech savvy, and generally would not consider themselves to be science-inclined. I will discuss some of the more interesting women I have profiled, as well as my observations on the efficacy of this method of history education.

  20. ImgCutout, an Engine of Instantaneous Astronomical Discovery

    Science.gov (United States)

    Nieto-Santisteban, M. A.; Szalay, A. S.; Gray, J.

    2004-07-01

    ImgCutout is a Web application that enables professional astronomers and the general public to interactively visualize and explore large, complex astronomical data sets. The application consists of a Web interface that calls a Web service, which accesses SkyServer, a 1 TB SQL Server database containing catalog data for 100 million objects, spectra and images from the Sloan Digital Sky Survey. ImgCutout builds, in real time, color mosaic-images of user-selected regions of the sky, and overlays additional information about astronomical and spatial objects in the database including: boundaries of survey fields and aperture plates, outlines of individual objects and data quality masks, in addition to locations of photometric and spectroscopic objects. The tool can search for lists of known objects, allows new database queries, and provides detailed information about selected objects.

  1. Optical studies conducted by Shogunal astronomers of Edo-period

    Science.gov (United States)

    Nakamura, Tsuko

    2005-05-01

    Although basic duty for astronomical officers of the Tokugawa Shogunal government had been to compile yearly and sometimes improve luni-solar calendars, they were obliged from necessity, toward the 19th century, to learn the astronomical navigation and optical instruments as well. This paper discusses why and how they coped with the fundamental optics. We also shed light on that Cornelis Douwes (1712-1773), the principal of the Amsterdam Naval Academy, made an important contribution to the Japanese astronomy of the Edo-period, through both the booklet on the octant written by him and his Dutch-translation enterprise of the four-volume books "Astronomie" authored by the famed French astronomer J. J. F. Lalande.

  2. Using Modern Technologies to Capture and Share Indigenous Astronomical Knowledge

    CERN Document Server

    Nakata, N M; Warren, J; Byrne, A; Pagnucco, M; Harley, R; Venugopal, S; Thorpe, K; Neville, R; Bolt, R

    2014-01-01

    Indigenous Knowledge is important for Indigenous communities across the globe and for the advancement of our general scientific knowledge. In particular, Indigenous astronomical knowledge integrates many aspects of Indigenous Knowledge, including seasonal calendars, navigation, food economics, law, ceremony, and social structure. We aim to develop innovative ways of capturing, managing, and disseminating Indigenous astronomical knowledge for Indigenous communities and the general public for the future. Capturing, managing, and disseminating this knowledge in the digital environment poses a number of challenges, which we aim to address using a collaborative project involving experts in the higher education, library, and industry sectors. Using Microsoft's WorldWide Telescope and Rich Interactive Narratives technologies, we propose to develop software, media design, and archival management solutions to allow Indigenous communities to share their astronomical knowledge with the world on their terms and in a cult...

  3. Photonic ring resonator filters for astronomical OH suppression

    Science.gov (United States)

    Ellis, S. C.; Kuhlmann, S.; Kuehn, K.; Spinka, H.; Underwood, D.; Gupta, R. R.; Ocola, L. E.; Liu, P.; Wei, G.; Stern, N. P.; Bland-Hawthorn, J.; Tuthill, P.

    2017-07-01

    Ring resonators provide a means of filtering specific wavelengths from a waveguide, and optionally dropping the filtered wavelengths into a second waveguide. Both of these features are potentially useful for astronomical instruments. In this paper we focus on their use as notch filters to remove the signal from atmospheric OH emission lines from astronomical spectra, however we also briefly discuss their use as frequency combs for wavelength calibration and as drop filters for Doppler planet searches. We derive the design requirements for ring resonators for OH suppression from theory and finite difference time domain simulations. We find that rings with small radii (0.9), but further optimisation is required to achieve higher Q and deeper notches, with current devices having $Q \\approx 4000$ and $\\approx 10$ dB suppression. The overall prospects for the use of ring resonators in astronomical instruments is promising, provided efficient fibre-chip coupling can be achieved.

  4. Examination and notes to the astronomical records in >SUISHU<.

    Science.gov (United States)

    Liu, Ciyuan

    1996-06-01

    Astronomical records are an important part in Chinese official historical books. Their main purpose was for astrology and they are an obstacle for historians who read those books. With modern astronomical methods, one can compute and examine most of those ancient records. By comparing the computed results with the original texts, one can examine the texts, find their mistakes, study their observation method and regulation, inspect astrological theory, take a deeper understanding to those important historical materials. As an example the author deals with the astronomcial records of Dynasties Liang and Chen for 60 years in >SUISHU<, the official history of Dynasty Sui. He also synthesized other historical sources in addition to the astronomical computation.

  5. Xia-Shang-Zhou Chronology Project and its astronomical problems

    Science.gov (United States)

    Liu, Ciyuan

    2001-06-01

    "Xia-Shang-Zhou Chronology Project" incorporates more than 200 experts on historical literature, ancient script, archeology, astronomy and C-14 measurement to promote early Chinese chronology (Xia, Shang, Zhou dynasties). Various astronomical problems have been studied in 12 separate groups. They are conjunctions of the five planets during the dynasties; Fire star for seasons determination; the famous solar eclipse in King Zhongkang's time; horizontal stars positions in Calendar Xiaxiaozheng; solar eclipse in King Yu; the lunar and solar eclipses recorded on oracle bones; celestial phenomena took place on King Wu's conquest; "double dawn" solar eclipse; lunar phase series on bronzes; calendar regulation of Zhou dynasty, and a comparison with foreign chronolgy. The astronomical conclusions of King Wuding by 5 lunar eclipses, King Wu by various astronomical records, King Yi by "double dawn" eclipse have been accepted as important frame of the Xia Shang Zhou chronology list while the years of west Zhou dynasty depended on the records of lunar phases.

  6. Radio Recombination Lines as Tools for Astronomers and Physicists

    Science.gov (United States)

    Gordon, M. A.

    2008-10-01

    Described by simple atomic theory published in 1913 by Niels Bohr, spectral lines in the radio range arising from transitions between large principal quantum numbers of atoms have proved to be useful tools for astronomers and physicists. Called ``radio recombination lines'' because of the wavelength range where most are observed, they are usually easy to detect, give unique information about astronomical objects, and facilitate the study of physical effects in environments that cannot be created in terrestrial laboratories. Observations have revealed unexpected results regarding thermodynamic populations of the principal quantum levels and about pressure broadening in astronomical environments. Detections of large-n lines, such as the n = 1006-->1010 absorption line of interstellar carbon, show the existence of atoms with classical diameters of about 0.1 mm, the thickness of a sheet of typing paper. This paper briefly discusses observations of Stark broadening reported by Bell et al. in 2002.

  7. IBC - ION BEAM CENTER

    Directory of Open Access Journals (Sweden)

    Johannes von Borany

    2017-12-01

    Full Text Available In the Ion Beam Center (IBC, various set-ups – electrostatic accelerators, ion implanters, plasma-based ion implantation equipment, low-energy ion tools, an ion microscope etc. – are combined into a unique facility for research and applications using ion beams. Almost all ions from stable chemical nuclides are available in the ion energy range from 10 eV to about 60 MeV. In addition to broad beams, also focused (down to 1 nm and highly-charged (charge state up to 45+ ion beams, or ions extracted from a plasma can be provided. In total, the IBC operates more than 30 dedicated tools or beamline end-stations. The specific expertise of IBC is the modification and analysis of solids by energetic ions aimed to develop novel materials for information technology, electronics or energy systems. In addition, ion beam analysis techniques became of increasing importance for interdisciplinary fields like geochemistry, climate or environmental research and resources technology. Special add-on services offered ensure a successful realization of user experiments. Based on a long-term expertise, specific equipment and common commercial procedures, the IBC is strongly active in the use of ion beam techniques for industrial applications aimed to initiate valuable product innovation.

  8. Dynamic analysis of centrifugal machines rotors supported on ball bearings by combined application of 3D and beam finite element models

    Science.gov (United States)

    Pavlenko, I. V.; Simonovskiy, V. I.; Demianenko, M. M.

    2017-08-01

    This research paper is aimed to investigating rotor dynamics of multistage centrifugal machines with ball bearings by using the computer programs “Critical frequencies of the rotor” and “Forced oscillations of the rotor,” which are implemented the mathematical model based on the use of beam finite elements. Free and forces oscillations of the rotor for the multistage centrifugal oil pump NPS 200-700 are observed by taking into account the analytical dependence of bearing stiffness on rotor speed, which is previously defined on the basis of results’ approximation for the numerical simulation in ANSYS by applying 3D finite elements. The calculations found that characteristic and constrained oscillations of rotor and corresponded to them forms of vibrations, as well as the form of constrained oscillation on the actual frequency for acceptable residual unbalance are determined.

  9. The Research Tools of the Virtual Astronomical Observatory

    Science.gov (United States)

    Hanisch, Robert J.; Berriman, G. B.; Lazio, T. J.; Project, VAO

    2013-01-01

    Astronomy is being transformed by the vast quantities of data, models, and simulations that are becoming available to astronomers at an ever-accelerating rate. The U.S. Virtual Astronomical Observatory (VAO) has been funded to provide an operational facility that is intended to be a resource for discovery and access of data, and to provide science services that use these data. Over the course of the past year, the VAO has been developing and releasing for community use five science tools: 1) "Iris", for dynamically building and analyzing spectral energy distributions, 2) a web-based data discovery tool that allows astronomers to identify and retrieve catalog, image, and spectral data on sources of interest, 3) a scalable cross-comparison service that allows astronomers to conduct pair-wise positional matches between very large catalogs stored remotely as well as between remote and local catalogs, 4) time series tools that allow astronomers to compute periodograms of the public data held at the NASA Star and Exoplanet Database (NStED) and the Harvard Time Series Center, and 5) A VO-aware release of the Image Reduction and Analysis Facility (IRAF) that provides transparent access to VO-available data collections and is SAMP-enabled, so that IRAF users can easily use tools such as Aladin and Topcat in conjuction with IRAF tasks. Additional VAO services will be built to make it easy for researchers to provide access to their data in VO-compliant ways, to build VO-enabled custom applications in Python, and to respond generally to the growing size and complexity of astronomy data. Acknowledgements: The Virtual Astronomical Observatory (VAO) is managed by the VAO, LLC, a non-profit company established as a partnership of the Associated Universities, Inc. and the Association of Universities for Research in Astronomy, Inc. The VAO is sponsored by the National Science Foundation and the National Aeronautics and Space Administration.

  10. Eminent Astronomers - Odessa University Graduates - In European Astronomy

    Science.gov (United States)

    Volyanskaya, M. Yu.

    1998-09-01

    A brief description of scientific activity of some eminent astronomers - graduates of the Odessa University named after I.I. Mechnikov (earlier - Novorossiiski University) in European astronomy is given: * Stratonov V.V. (1869-1938), professor, wellknown specialist in stellar astronomy, who was exiled abroad in 1992 among many scientists and writers, lived in Germany and Prague, where died; * Gansky A.P. (1870-1908) - famous investagator of the Sun, worked at the Meudon Observatory, ascended 9 times to Mount Blanc to make observations, was awarded by P.Z.C. Jansen medal of the Paris Academy of Sciences; * Donitch N.N. (1874-1956) - wellknown investigator of the Solar system, one of the first Romanian astronomers, a brilliant personality of the astronomical community of his time, a honorary member of the Romanian Academy of Sciences, died in Nice (France); * Zalesky Bogdan (1887-1927), specialist in astrometry, which became a wellknown astronomer in Poland. One of the founders and the first director of the University Observatory in Poznan; * Witkowsky Josef (1892- 1976) - specialist in astrometry, practical astronomy, and tidal phenomena studies, history of astronomy. Professor, Director of the Astronomical Centre in Poznan; *Stoiko N.M. ((1894-1976) - investigator of the irregularities of the Earth's rotation, the Earth's poles motions and the universal time determination. A member of many scientific societies. He was awarded by prizes of the Paris Academy of Sciences, of the French astronomical society, of the Royal Academy of Belgium. He worked at the Paris Observatory and was one of the Directors of the International Time Service; * Jardecky (Zhardecky) Vietcheslaw (1896-1962), worked at the Department of Mathematics of the Beograd University; eminent specialist in the field of Mechanics of Fluids; After the Second World War he emmigrated to the USA, Professor of Geophysics at the Columbia Univeristy (New York), where died.

  11. Application of Astronomical Compositions in Small Architectural Forms

    Science.gov (United States)

    Haykazun, Ani

    2016-12-01

    The small architectural forms are an important part of the Armenian architecture. Their compositions are diverse including quadrihedral structures, cross-stones, monuments, gravestones, memorial stones, etc. From ancient times to the late middle ages, and up to themodern small architectural forms, there are many decorative elements of astronomical character. Among them, one can more often see stars, the sun, the moon, the sky, the planets, the sign of eternity and other symbolic decorative images, which play a major role in the formation of the artistic image of the architectural compositions. The analysis of application of astronomical compositions will help more comprehensively introduce the compositional peculiarities of the small architectural forms.

  12. The Potential of Deep Learning with Astronomical Data

    Science.gov (United States)

    Schafer, Chad

    2017-06-01

    Modern astronomical surveys yield massive catalogs of noisy high-dimensional objects, e.g., images, spectra, and light curves. Valuable information stored in individual objects can be lost when ad hoc approaches of feature extraction are used in an effort to build data sets amenable to established data analysis tools. Deep learning procedures provide a promising avenue to enabling the use of data in their raw form and hence allowing both for estimates of greater accuracy and for novel discoveries with greater confidence. This talk will give an overview of deep learning and its potential in astronomical applications.

  13. Astroinformatics, data mining and the future of astronomical research

    Energy Technology Data Exchange (ETDEWEB)

    Brescia, Massimo, E-mail: longo@na.infn.it [INAF, Astronomical Obs. of Capodimonte, Via Moiariello 16, I-80131 Napoli (Italy); Longo, Giuseppe [Department of Physics, University Federico II, Via Cintia 6, 80126 Napoli (Italy); Department of Astronomy, Caltech, Pasadena (United States)

    2013-08-21

    Astronomy, as many other scientific disciplines, is facing a true data deluge which is bound to change both the praxis and the methodology of every day research work. The emerging field of astroinformatics, while on the one end appears crucial to face the technological challenges, on the other is opening new exciting perspectives for new astronomical discoveries through the implementation of advanced data mining procedures. The complexity of astronomical data and the variety of scientific problems, however, call for innovative algorithms and methods as well as for an extreme usage of ICT technologies.

  14. Beam collimator

    CERN Multimedia

    1977-01-01

    A four-block collimator installed on a control table for positioning the alignment reference marks. Designed for use with SPS secondary beams, the collimator operates under vacuum conditions. See Annual Report 1976 p. 121 and photo 7701014.

  15. Simulation of the beam halo from the beam-beam interaction in LEP

    Energy Technology Data Exchange (ETDEWEB)

    Chen, T.; Irwin, J.; Siemann, R.

    1994-02-01

    The luminosity lifetimes of e{sup +}e{sup {minus}} colliders are often dominated by the halo produced by the beam-beam interaction. They have developed a simulation technique to model this halo using the flux across boundaries in amplitude space to decrease the CPU time by a factor of one-hundred or more over `brute force` tracking. It allows simulation of density distributions and halos corresponding to realistic lifetimes. Reference 1 shows the agreement with brute force tracking in a number of cases and the importance of beam-beam resonances in determining the density distribution of large amplitudes. this research is now directed towards comparisons with operating colliders and studies of the combined effects of lattice and beam-beam nonlinearities. LEP offers an ideal opportunity for both, and in this paper they are presenting the first results of LEP simulations.

  16. Potential of 80-kV high-resolution cone-beam CT imaging combined with an optimized protocol for neurological surgery

    Energy Technology Data Exchange (ETDEWEB)

    Kanayama, Seisaku; Hara, Takayuki [Toranomon Hospital, Department of Neurosurgery, Tokyo (Japan); Hamada, Yusuke [Toranomon Hospital, Department of Radiology, Tokyo (Japan); Matsumaru, Yuji [Toranomon Hospital, Department of Neuro-Endovascular Therapy, Tokyo (Japan)

    2014-11-05

    With the development of computed tomography (CT) and magnetic resonance imaging (MRI), the use of conventional X-ray angiography including digital subtraction angiography (DSA) for diagnosis has decreased, as it is an invasive technique with a risk of neurological complications. However, X-ray angiography imaging technologies have progressed markedly, along with the development of endovascular treatments. A newly developed angiography technique using cone-beam CT (CBCT) technology provides higher spatial resolution than conventional CT. Herein, we describe the potential of this technology for neurosurgical operations with reference to clinical cases. Two hundred twenty-five patients who received 80-kV high-resolution CBCT from July 2011 to June 2014 for preoperative examinations were included in this study. For pathognomonical cases, images were taken with suitable reconstruction modes and contrast protocols. Cases were compared with intraoperative findings or images from other modalities. We observed the following pathognomonical types: (1) imaging of the distal dural ring (DDR) and the surrounding structure for paraclinoid aneurysms, (2) imaging of thin blood vessels, and (3) imaging of both brain tumors and their surrounding anatomy. Our devised 80-kV high-resolution CBCT imaging system provided clear visualization of detailed anatomy when compared with other modalities in almost all cases. Only two cases provided poor visualization due to movement artifact. Eighty-kilovolt high-resolution CBCT has the potential to provide detailed anatomy for neurosurgical operations when utilizing suitable modes and contrast protocols. (orig.)

  17. Evaluation study of the sinus lift technique in combination with autologous bone augmentation in dogs' frontal sinus. Limited cone beam CT image and histopathological analyses

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Tatsuo [Tokyo Women' s Medical Coll. (Japan). School of Medicine

    2002-08-01

    The posterior area of the maxilla has often been considered inadequate for the insertion of dental implants due to insufficient height of the alveolar bone by atrophic reduction and the maxillary sinus expansion. This anatomic problem may be resolved with augmentation of the floor of the maxillary sinus. The purpose of this study is to evaluate the effectiveness of sinus lift and grafting with the iliac crest bone performed in the dog frontal sinus as a model of the human maxillary sinus. Time course evaluations of bone volume after insertion of implants were performed by the limited cone beam CT (Ortho-CT), histopathological study and NIH-image digital analysis. New bone formation was identified as early as 2 weeks after the implant insertion. The bone volume was increased continuously until 13th week. High-density bone was found in the cervix of the implant after 26 weeks. However, the bone was lost at apex area of the implant and air cavity of the frontal sinus expanded. Ortho-CT findings showed good correlation with histopathological course of the lesion and bone volume identified by the NIH image analysis. The results revealed first time whole course of the bone remodeling after implant insertion into the frontal sinus of a dog. The data also provide an appropriate timing of the implant prosthesis and promise usefulness of the Ortho-CT in planning efficient implant treatment. (author)

  18. Recent Advances for LGBT Astronomers in the United States

    Science.gov (United States)

    Dixon, William V.; Rigby, Jane; Oppenheimer, Rebecca

    2015-08-01

    The legal environment for lesbian, gay, bisexual, and transgender (LGBT) astronomers in the United States has changed dramatically in recent years. In 2013, the Supreme Court ruled that Section 3 of the Defense of Marriage Act (DOMA), which had barred the federal government from recognizing same-sex marriages, was unconstitutional. This decision particularly affects astronomers, since astronomers in the U.S. are more likely than the general population to be foreign nationals, to have a foreign-born spouse, or to work for the federal government. In 2014, the Attorney General directed the Department of Justice to take the position in litigation that the protection of Title VII of the Civil Rights Act of 1964 extends to claims of discrimination based on an individual’s gender identity, including transgender status. Title VII makes it unlawful for employers to discriminate in the employment of an individual “because of such individual’s... sex,” among other protected characteristics. As of March 2015, more than 70% of the population lives in states that recognize same-sex marriage, and the Supreme Court is expected to rule on the constitutionality of the remaining same-sex marriage bans during the current term. In this poster, we discuss these advances and their implications for the personal and professional lives of LGBT astronomers across the United States.

  19. Factors Contributing to Lifelong Science Learning: Amateur Astronomers and Birders

    Science.gov (United States)

    Jones, M. Gail; Corin, Elysa Nicole; Andre, Thomas; Childers, Gina M.; Stevens, Vanessa

    2017-01-01

    This research examined lifelong science learning reported by amateur astronomers and birders. One hundred seven adults who reported engaging in an informal (out-of-school) science interest were interviewed as part of an ongoing series of studies of lifelong science learners. The goal of the study was to gain insight into how and why amateur…

  20. Astronomy for Astronomical Numbers: A Worldwide Massive Open Online Class

    Science.gov (United States)

    Impey, Chris D.; Wenger, Matthew C.; Austin, Carmen L.

    2015-01-01

    Astronomy: State of the Art is a massive, open, online class (MOOC) offered through Udemy by an instructional team at the University of Arizona. With nearly 24,000 enrolled as of early 2015, it is the largest astronomy MOOC available. The astronomical numbers enrolled do not translate into a similar level of engagement. The content consists of 14…

  1. The Astronomical Information Infrastructure from the End-User Perspective

    NARCIS (Netherlands)

    Hogeveen, S.J.

    1995-01-01

    Information Technology (IT) today has found so many applications in as- tronomy, that we may speak of an electronic `Astronomical Information Infrastructure' (AII). At this moment, the AII really is nothing but a collection of disparate services. Over the last few years the collection has grown

  2. How did the Supreme Court ruling on DOMA affect astronomers?

    Science.gov (United States)

    Rigby, Jane R.; The AAS Working Group on LGBTIQ Equality

    2014-01-01

    In June 2013, the United States Supreme Court ruled that Section 3 of the Defense of Marriage Act (DOMA) was unconstitutional. Section 3 had barred the federal government from recognizing same-sex marriages. The decision in United States v. Windsor, made headlines around the world, and particularly affected astronomers, since astronomers in the US are more likely than the general population to be foreign nationals, to have a foreign-born spouse, or to work for the federal government. In this poster, we highlight some of the real-world ways that the Windsor case has affected US astronomers and our profession. Bi-national couples can now apply for green cards granting permanent residency. Scientists who work for the federal government, including NASA and the NSF, can now obtain health insurance for a same-sex spouse. From taxes to death benefits, health insurance to daycare, immigration to ethics laws, the end of S3 of DOMA has had profoundly improved the lives of US scientists who are lesbian, gay, bisexual, or transgender (LGBT). Here we, highlight several real-world examples of how DOMA's demise has improved the lives and careers of US astronomer.

  3. GPU accelerated processing of astronomical high frame-rate videosequences

    Science.gov (United States)

    Vítek, Stanislav; Švihlík, Jan; Krasula, Lukáš; Fliegel, Karel; Páta, Petr

    2015-09-01

    Astronomical instruments located around the world are producing an incredibly large amount of possibly interesting scientific data. Astronomical research is expanding into large and highly sensitive telescopes. Total volume of data rates per night of operations also increases with the quality and resolution of state-of-the-art CCD/CMOS detectors. Since many of the ground-based astronomical experiments are placed in remote locations with limited access to the Internet, it is necessary to solve the problem of the data storage. It mostly means that current data acquistion, processing and analyses algorithm require review. Decision about importance of the data has to be taken in very short time. This work deals with GPU accelerated processing of high frame-rate astronomical video-sequences, mostly originating from experiment MAIA (Meteor Automatic Imager and Analyser), an instrument primarily focused to observing of faint meteoric events with a high time resolution. The instrument with price bellow 2000 euro consists of image intensifier and gigabite ethernet camera running at 61 fps. With resolution better than VGA the system produces up to 2TB of scientifically valuable video data per night. Main goal of the paper is not to optimize any GPU algorithm, but to propose and evaluate parallel GPU algorithms able to process huge amount of video-sequences in order to delete all uninteresting data.

  4. Jan Hendrik Oort – A Complete Astronomer (1900 –1992)

    Indian Academy of Sciences (India)

    IAS Admin

    therefore makes our vision shortsighted. The radio map revealed spiral arms of our Galaxy, and showed that the Milky Way was similar in appearance to other spiral galaxies. Oort is remembered not only as the father of Dutch astronomy, but also as a major figure in spearheading astronomical research in Europe, and in ...

  5. This Month in Astronomical History: Preliminary Survey Results

    Science.gov (United States)

    Wilson, Teresa

    2017-01-01

    This Month in Astronomical History is a short (~500 word) column on the AAS website that revisits significant astronomical events or the lives of people who have made a large impact on the field. The monthly column began in July 2016 at the request of the Historical Astronomical Division. Examples of topics that have been covered include Comet Shoemaker-Levy’s collision with Jupiter, the discovery of the moons of Mars, the life of Edwin Hubble, Maria Mitchell’s comet discovery, and the launch of Sputnik II. A survey concerning the column is in progress to ensure the column addresses the interests and needs of a broad readership, including historians, educators, research astronomers, and the general public. Eleven questions focus on the style and content of the column, while eight collect simple demographics. The survey has been available on the AAS website since and was mentioned in several AAS newsletters; however, non-members of AAS were also recruited to include respondents from a variety of backgrounds. Preliminary results of the survey are presented and will be used to hone the style and content of the column to serve the widest possible audience. Responses continue to be collected at: https://goo.gl/forms/Lhwl2aWJl2Vkoo7v1

  6. Revised Miocene splice, astronomical tuning and calcareous plankton biochronology

    NARCIS (Netherlands)

    Zeeden, C.; Hilgen, F.; Westerwold, T.; Lourens, L.; Röhl, Ursula; Bickert, Torsten

    2013-01-01

    The distinctly cyclic sediments recovered during ODP Leg 154 played an important role in constructing the astronomical time scale and associated astro(bio)chronology for the Miocene, and in deciphering ocean–climate history. The accuracy of the timescale critically depends on the reliability of

  7. The Top Ten Astronomical 'breakthroughs' of the 20th century

    Directory of Open Access Journals (Sweden)

    Hughes, D. W.

    2007-10-01

    Full Text Available Astronomy was revolutionized in the 20th century. The electron was discovered in 1897 and this transformed spectroscopy and introduced plasma and magnetohydrodynamic physics and astro-chemistry. Einstein’s E = mc2, solved the problem of stellar energy generation and spawned the study of elemental nuclear synthesis. Large telescopes led to a boom in astronomical spectroscopic and photometric data collection, leading to such cornerstones as the Hertzprung-Russell diagram and the mass-luminosity relationship, and to the realization that the Universe contained a multitude of galaxies and was expanding. Radio astronomy was introduced and the advent of the space age saw the astronomical wavelength range expand into the ultraviolet, X-ray and gamma-ray regions, as well as the infrared and millimetre. We also startedwandering around roaming the Solar System instead of merely glimpsing its members from the bottom of our warm, turbulent atmosphere. Astronomical “breakthroughs” abounded. We have asked astronomers to select their “top ten” and these are listed and discussed in this paper.

  8. Analytical algorithms of relativistic reduction of astronomical observations.

    Science.gov (United States)

    Brumberg, V. A.; Bretagnon, P.; Francou, G.

    Using the analytical planetary theories VSOP87 (Bretagnon and Francou, 1988) and the relativistic theory of astronomical reference systems of Brumberg and Kopejkin (1989) the authors have derived the analytical expressions of the relativistic quantities enabling one to set the relationships between (1) TCB and TCG, (2) barycentric spatial coordinates and geocentric spatial coordinates and (3) observer's proper time and TCG.

  9. Radio Recombination Lines. Their Physics and Astronomical Applications

    Science.gov (United States)

    Gordon, M. A.; Sorochenko, R. L.

    2002-11-01

    This book is a comprehensive guide to the physics and observations of Radio Recombination Lines from astronomical sources, written for astronomers, physicists, and graduate students. It serves as a graduate-level textbook. It includes the history of RRL detections, the astrophysics underlying their intensities and line shapes including topics like departures from LTE and Stark broadening, the maximum possible size of an atom, as well as detailed descriptions of the astronomical topics for which RRLs have proved to be effective tools. The text includes more than 250 equations and 110 illustrations. It also contains hundreds of specific references to the astronomical literature to enable readers to explore additional details. The appendix includes supplementary information such as the detailed physics underlying the Bohr atomic model, tables of RRL frequencies including fine structure components, techniques for calculating hydrogenic oscillator strengths, FORTRAN code for calculating departure coefficients, and a discussion with formulas for converting observational (telescope) intensity units to astrophysical ones. Link: http://www.wkap.nl/prod/b/1-4020-1016-8

  10. Brightness Variations of Sun-like Stars: The Mystery Deepens - Astronomers facing Socratic "ignorance"

    Science.gov (United States)

    2009-12-01

    An extensive study made with ESO's Very Large Telescope deepens a long-standing mystery in the study of stars similar to the Sun. Unusual year-long variations in the brightness of about one third of all Sun-like stars during the latter stages of their lives still remain unexplained. Over the past few decades, astronomers have offered many possible explanations, but the new, painstaking observations contradict them all and only deepen the mystery. The search for a suitable interpretation is on. "Astronomers are left in the dark, and for once, we do not enjoy it," says Christine Nicholls from Mount Stromlo Observatory, Australia, lead author of a paper reporting the study. "We have obtained the most comprehensive set of observations to date for this class of Sun-like stars, and they clearly show that all the possible explanations for their unusual behaviour just fail." The mystery investigated by the team dates back to the 1930s and affects about a third of Sun-like stars in our Milky Way and other galaxies. All stars with masses similar to our Sun become, towards the end of their lives, red, cool and extremely large, just before retiring as white dwarfs. Also known as red giants, these elderly stars exhibit very strong periodic variations in their luminosity over timescales up to a couple of years. "Such variations are thought to be caused by what we call 'stellar pulsations'," says Nicholls. "Roughly speaking, the giant star swells and shrinks, becoming brighter and dimmer in a regular pattern. However, one third of these stars show an unexplained additional periodic variation, on even longer timescales - up to five years." In order to find out the origin of this secondary feature, the astronomers monitored 58 stars in our galactic neighbour, the Large Magellanic Cloud, over two and a half years. They acquired spectra using the high resolution FLAMES/GIRAFFE spectrograph on ESO's Very Large Telescope and combined them with images from other telescopes [1

  11. Laser beam splitting by polarization encoding.

    Science.gov (United States)

    Wan, Chenhao

    2015-03-20

    A scheme is proposed to design a polarization grating that splits an incident linearly polarized beam to an array of linearly polarized beams of identical intensity distribution and various azimuth angles of linear polarization. The grating is equivalent to a wave plate with space-variant azimuth angle and space-variant phase retardation. The linear polarization states of all split beams make the grating suitable for coherent beam combining architectures based on Dammann gratings.

  12. Specification of the Beam Position Measurement in the PS Machine

    CERN Document Server

    Bravin, Enrico; Chanel, M; Ludwig, M; Métral, Elias; Métral, G; Potier, J P; Raich, U; Scrivens, R; Steerenberg, R; CERN. Geneva. AB Department

    2003-01-01

    This specification, drawn up by the instrumentation specification board 2, describes the requirements concerning orbit and trajectory measurements in the PS machine. The orbit measurement and the trajectory measurement are both indispensable in order to be able to guarantee the correct beam quality for beams like LHC, the future Grand Sasso beam, the nTOF beam and surely the combined operation of the nTOF beam and the East Area beam.

  13. The Astronomical Virtual Observatory: Lessons Learned, Looking Forward

    Science.gov (United States)

    Genova, F.

    2012-09-01

    The astronomical Virtual Observatory (VO) aims at providing seamless access to the wealth of the discipline's on-line resources, hence at developing global interoperability between them. This is coordinated by the International Virtual Observatory Alliance (IVOA). The paper summarizes the VO history and current evolution. During the first period of VO development, a huge amount of work has been devoted to the development of basic interoperability standards, to set up the VO framework for publication of data and for tools interoperability. This has proven to be a major asset for seamless usage of data. Now the VO is in operation, and the emphasis on supporting the take-up by astronomers and data providers, as well as on outreach, is increasing. A census of European astronomical data centres performed in 2009/2010 shows a large interest in the VO, and a wide diversity of sizes and organisations, in the data centre community. The different strands of work of an operational VO, and the challenges ahead are described, taking in particular the example of the European VO. The European implementation of the VO has been moulded by the specific organisation of European astronomy, with complementary roles of the national and European levels. Local and national projects contribute to the VO development and implementation in their domains of interest and expertise. Several projects supported by the European Commission have helped to shape Euro-VO, with a strong emphasis on coordination of national and intergovernmental agency projects, with actions towards astronomers, data centres and VO developers, including during the last period of outreach towards education and the public. The Astronet Infrastructure Roadmap for European astronomy (2009) has recognized data and the VO as one of the infrastructures of astronomy. The way forward in this context is discussed. In conclusion, the astronomical data infrastructure is put in perspective with the general trends around scientific

  14. Proton-beam, intensity-modulated, and/or intraoperative electron radiation therapy combined with aggressive anterior surgical resection for retroperitoneal sarcomas.

    Science.gov (United States)

    Yoon, Sam S; Chen, Yen-Lin; Kirsch, David G; Maduekwe, Ugwuji N; Rosenberg, Andrew E; Nielsen, G Petur; Sahani, Dushyant V; Choy, Edwin; Harmon, David C; DeLaney, Thomas F

    2010-06-01

    We sought to reduce local recurrence for retroperitoneal sarcomas by using a coordinated strategy of advanced radiation techniques and aggressive en-bloc surgical resection. Proton-beam radiation therapy (PBRT) and/or intensity-modulated radiation therapy (IMRT) were delivered to improve tumor target coverage and spare selected adjacent organs. Surgical resection of tumor and adjacent organs was performed to obtain a disease-free anterior margin. Intraoperative electron radiation therapy (IOERT) was delivered to any close posterior margin. Twenty patients had primary tumors and eight had recurrent tumors. Tumors were large (median size 9.75 cm), primarily liposarcomas and leiomyosarcomas (71%), and were mostly of intermediate or high grade (81%). PBRT and/or IMRT were delivered to all patients, preferably preoperatively (75%), to a median dose of 50 Gy. Surgical resection included up to five adjacent organs, most commonly the colon (n = 7) and kidney (n = 7). Margins were positive for disease, usually posteriorly, in 15 patients (54%). IOERT was delivered to the posterior margin in 12 patients (43%) to a median dose of 11 Gy. Surgical complications occurred in eight patients (28.6%), and radiation-related complications occurred in four patients (14%). After a median follow-up of 33 months, only two patients (10%) with primary disease experienced local recurrence, while three patients (37.5%) with recurrent disease experienced local recurrence. Aggressive resection of retroperitoneal sarcomas can achieve a disease-negative anterior margin. PBRT and/or IMRT with IOERT may possibly deliver sufficient radiation dose to the posterior margin to control microscopic residual disease. This strategy may minimize radiation-related morbidity and reduce local recurrence, especially in patients with primary disease.

  15. Simulation of bending stress variation in long buried thick-walled pipes under the earth’s movement using combined linear dynamics and beam theories

    Directory of Open Access Journals (Sweden)

    Salau Tajudeen A.O.

    2014-01-01

    Full Text Available This study reported a simulation approach to the understanding of the interactions between a buried pipe and the soil system by computing the bending stress variation of harmonically-excited buried pipes. The established principles of linear dynamics theory and simple beam theory were utilised in the analysis of the problem of buried pipe bending stress accumulation and its dynamics. With regards to the parameters that influence the bending stress variations, the most important are the isolation factor, uniform external load, and the corresponding limiting conditions. The simulated mathematical expressions, containing static and dynamic parameters of the buried pipe and earth, were coded in Fortran programming language and applied in the simulation experiment. The results obtained showed that harmonically-excited buried thick-walled pipe became stable and effective when the ratio of the natural frequency of vibration to the forced frequency is greater than 2.0, whenever the damped factor is used as the control parameter for the maximum bending stress. The mirror image of the stress variation produces variation in the location of the maximum bending stress in quantitative terms. The acceptable pipe materials for the simulated cases must have yield strength in bending greater than or equal to 13.95 MPa. The results obtained in this work fill a gap in the literature and will be useful to pipeline engineers and designers, as well as to environmental scientists in initialising and controlling environmental issues and policy formulation concerning the influence of buried pipe on the soil and water in the environment.

  16. International Astronomical Search Collaboration -- Astronomical Discovery Program for High School and College Students

    Science.gov (United States)

    Miller, Patrick

    2012-01-01

    Centered at Hardin-Simmons University (Abilene, TX) the International Astronomical Search Collaboration (IASC) has conducted successful student-based asteroid search programs, called campaigns. Since 2006 these campaigns have engaged 3,000 high school and college students per year. These students come from 300 schools worldwide located in more than 40 countries on 5 continents. Students have made thousands of observations of near-Earth objects and >300 provisional discoveries of Main Belt asteroids, both reported to the Minor Planet Center (Harvard). To date students have 15 numbered discoveries, catalogued by the IAU and currently being named by the student discoverers. The first telescope of the Panoramic Survey and Rapid Response System (PS1, University of Hawaii) is conducting the largest optical survey ever attempted. In support of education and public outreach, Pan-STARRS collaborated with IASC in 2010-2012 to use the PS1 images in the student asteroid search and discovery campaigns. The PS1 images are wide field with 7o FOV and 1.4 Gpix in size. These were partitioned into 144 sub-images and distributed to 40 high schools in Texas, Hawaii, Washington, Germany, Taiwan, Poland, Brazil, and Bulgaria. In two 6-week campaigns per year, students from these schools made 1000 preliminary asteroid discoveries. This poster presents the results of the first and second year of the IASC-PS1 campaigns plus other asteroid search campaigns conducted by IASC. Also, plans will be described for future campaigns. These future campaigns will reach 500 schools in 2012 and 1,000 high schools within the coming 36 months.

  17. Precise deformation measurement of prestressed concrete beam during a strain test using the combination of intersection photogrammetry and micro-network measurement

    Science.gov (United States)

    Urban, Rudolf; Braun, Jaroslav; Štroner, Martin

    2015-05-01

    The prestressed thin-walled concrete elements enable the bridge a relatively large span. These structures are advantageous in economic and environmental way due to their thickness and lower consumption of materials. The bending moments can be effectively influenced by using the pre-stress. The experiment was done to monitor deformation of the under load. During the experiment the discrete points were monitored. To determine a large number of points, the intersection photogrammetry combined with precise micro-network were chosen. Keywords:

  18. Sports stars: analyzing the performance of astronomers at visualization-based discovery

    OpenAIRE

    Fluke, C. J.; Parrington, L.; Hegarty, S.; MacMahon, C.; Morgan, S.; Hassan, A. H.; Kilborn, V. A.

    2017-01-01

    In this data-rich era of astronomy, there is a growing reliance on automated techniques to discover new knowledge. The role of the astronomer may change from being a discoverer to being a confirmer. But what do astronomers actually look at when they distinguish between "sources" and "noise?" What are the differences between novice and expert astronomers when it comes to visual-based discovery? Can we identify elite talent or coach astronomers to maximize their potential for discovery? By look...

  19. Method and apparatus for laser-controlled proton beam radiology

    Science.gov (United States)

    Johnstone, Carol J.

    1998-01-01

    A proton beam radiology system provides cancer treatment and proton radiography. The system includes an accelerator for producing an H.sup.- beam and a laser source for generating a laser beam. A photodetachment module is located proximate the periphery of the accelerator. The photodetachment module combines the H.sup.- beam and laser beam to produce a neutral beam therefrom within a subsection of the H.sup.- beam. The photodetachment module emits the neutral beam along a trajectory defined by the laser beam. The photodetachment module includes a stripping foil which forms a proton beam from the neutral beam. The proton beam is delivered to a conveyance segment which transports the proton beam to a patient treatment station. The photodetachment module further includes a laser scanner which moves the laser beam along a path transverse to the cross-section of the H.sup.- beam in order to form the neutral beam in subsections of the H.sup.- beam. As the scanning laser moves across the H.sup.- beam, it similarly varies the trajectory of the proton beam emitted from the photodetachment module and in turn varies the target location of the proton beam upon the patient. Intensity modulation of the proton beam can also be achieved by controlling the output of the laser.

  20. Different Categories of Astronomical Heritage: Issues and Challenges

    Science.gov (United States)

    Ruggles, Clive

    2012-09-01

    Since 2008 the AWHWG has, on behalf of the IAU, been working with UNESCO and its advisory bodies to help identify, safeguard and promote cultural properties relating to astronomy and, where possible, to try to facilitate the eventual nomination of key astronomical heritage sites onto the World Heritage List. Unfortunately, the World Heritage Convention only covers fixed sites (i.e., the tangible immovable heritage of astronomy), and a key question for the UNESCO-IAU Astronomy and World Heritage Initiative (AWHI) is the extent to which the tangible moveable and intangible heritage of astronomy (e.g. moveable instruments; ideas and theories) influence the assessment of the tangible immovable heritage. Clearly, in an ideal world we should be concerned not only with tangible immovable heritage but, to quote the AWHWG's own Terms of Reference, ``to help ensure that cultural properties and artefacts significant in the development of astronomy, together with the intangible heritage of astronomy, are duly studied, protected and maintained, both for the greater benefit of humankind and to the potential benefit of future historical research''. With this in mind, the IAU/INAF symposium on ``Astronomy and its Instruments before and after Galileo'' held in Venice in Sep-Oct 2009 recommended that urgent steps should be taken 1. to sensitise astronomers and the general public, and particularly observatory directors and others with direct influence and control over astronomical resources, to the importance of identifying, protecting and preserving the various material products of astronomical research and discovery that already have, or have significant potential to acquire, universal value; (N.B. National or regional interests and concerns have no relevance in the assessment of ``universal value'', which, by definition, extends beyond cultural boundaries and, by reasonable expectation, down the generations into the future. 2. to identify modes of interconnectivity between

  1. Astronomical Optical Interferometry. I. Methods and Instrumentation

    Directory of Open Access Journals (Sweden)

    Jankov, S.

    2010-12-01

    Full Text Available Previous decade has seen an achievement of large interferometricprojects including 8-10m telescopes and 100m class baselines. Modern computerand control technology has enabled the interferometric combination of lightfrom separate telescopes also in the visible and infrared regimes. Imagingwith milli-arcsecond (mas resolution and astrometry with micro-arcsecond($mu$as precision have thus become reality. Here, I review the methods andinstrumentation corresponding to the current state in the field ofastronomical optical interferometry. First, this review summarizes thedevelopment from the pioneering works of Fizeau and Michelson. Next, thefundamental observables are described, followed by the discussion of the basicdesign principles of modern interferometers. The basic interferometrictechniques such as speckle and aperture masking interferometry, aperture synthesisand nulling interferometry are disscused as well. Using the experience ofpast and existing facilities to illustrate important points, I considerparticularly the new generation of large interferometers that has beenrecently commissioned (most notably, the CHARA, Keck, VLT and LBTInterferometers. Finally, I discuss the longer-term future of opticalinterferometry, including the possibilities of new large-scale ground-based projects and prospects for space interferometry.

  2. Top astronomers head to the city. Experts to talk on exciting quasar discoveries.

    CERN Multimedia

    Grant, S

    2002-01-01

    The UK National Astronomy Meeting - NAM 2002 - is at Bristol University this week. The meeting is one of the most important regular gatherings of astronomers in the UK. Sponsored by the Royal Astronomical Society and PPARC, it should attract about 300 astronomers from the UK and beyond.

  3. Superresolution beams

    CSIR Research Space (South Africa)

    Ngcobo, S

    2012-07-01

    Full Text Available stream_source_info Ngcobo2_2012.pdf.txt stream_content_type text/plain stream_size 3697 Content-Encoding ISO-8859-1 stream_name Ngcobo2_2012.pdf.txt Content-Type text/plain; charset=ISO-8859-1 SUPERRESOLUTION BEAMS S... University of Johannesburg, PO Box 524, Auckland Park, 2006, South Africa Slide 2 ? CSIR 2011 www.csir.co.za Outline ? Introduction ? Concept of superresolution beams ? Transformation of TEM00 to TEM10 ? Resonator...

  4. Superresolution beams

    CSIR Research Space (South Africa)

    Ngcobo, S

    2011-11-01

    Full Text Available stream_source_info Ngcobo3_2012.pdf.txt stream_content_type text/plain stream_size 4467 Content-Encoding ISO-8859-1 stream_name Ngcobo3_2012.pdf.txt Content-Type text/plain; charset=ISO-8859-1 SUPERRESOLUTION BEAMS S... 2011 www.csir.co.za Outline ? Introduction ? Concept of superresolution beams ? Transformation of TEM00 to TEM10 ? Resonator design and experimental setup ? Results ? Conclusions ? Future work Slide 3 ? CSIR 2011...

  5. Chemoradiation in cervical cancer with cisplatin and high-dose rate brachytherapy combined with external beam radiotherapy. Results of a phase-II study

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, H.G.; Laban, C.; Puschmann, D.; Koelbl, H. [Dept. of Gynecology, Martin-Luther Univ. Halle-Wittenberg (Germany); Kuhnt, T.; Pigorsch, S.; Dunst, J.; Haensgen, G. [Dept. of Radiotherapy, Martin-Luther Univ. Halle-Wittenberg (Germany)

    2002-07-01

    Background: In 1999, five randomized studies demonstrated that chemoradiation with cisplatin and low-dose rate (LDR) brachytherapy has a benefit in locally advanced cervical cancer and for surgically treated patients in high-risk situations. We evaluated the safety and efficacy of concomitant chemoradiation with cisplatin and high-dose rate (HDR) brachytherapy in patients with cervical cancer. Patients and Method: 27 patients were included in our phase-II trial: 13 locally advanced cases (group A) and 14 adjuvant-therapy patients in high-risk situations (group B). A definitive radiotherapy was performed with 25 fractions of external beam therapy (1.8 Gy per fraction/middle shielded after eleven fractions). Brachytherapy was delivered at HDR schedules with 7 Gy in point A per fraction (total dose 35 Gy) in FIGO Stages IIB-IIIB. The total dose of external and brachytherapy was 70 Gy in point A and 52-54 Gy in point B. All patients in stage IVA were treated without brachytherapy. Adjuvant radiotherapy was performed with external beam radiotherapy of the pelvis with 1.8 Gy single-dose up to 50.4 Gy. Brachytherapy was delivered at HDR schedules with two fractions of 5 Gy only in patients with tumor-positive margins or tumor involvement of the upper vagina. The chemotherapeutic treatment schedule provided six courses of cisplatin 40 mg/m{sup 2} weekly recommended in the randomized studies GOG-120 and -123. Results: A total of 18/27 patients (66.7%) completed all six courses of chemotherapy. Discontinuation of radiotherapy due to therapy-related morbidity was not necessary in the whole study group. G3 leukopenia (29.6%) was the only relevant acute toxicity. There were no differences in toxicity between group A and B. Serious late morbidity occurred in 2/27 patients (7.4%). 12/13 patients (92.3%) with IIB-IVA cervical cancer showed a complete response (CR). 13/14 adjuvant cases (92.8%) are free of recurrence (median follow up: 19.1 months). Conclusion: Concomitant

  6. The PACA Project: When Amateur Astronomers Become Citizen Scientists

    Science.gov (United States)

    Yanamandra-Fisher, P. A.

    2014-12-01

    The Pro-Am Collaborative Astronomy (PACA) project evolved from the observational campaign of C/2012 S1 or C/ISON in 2013. Following the success of the professional-amateur astronomer collaboration in scientific research via social media, it is now implemented in other comet observing campaigns. While PACA identifies a consistent collaborative approach to pro-am collaborations, given the volume of data generated for each campaign, new ways of rapid data analysis, mining access and storage are needed. Several interesting results emerged from the synergistic inclusion of both social media and amateur astronomers: (1) the establishment of a network of astronomers and related professionals, that can be galvanized into action on short notice to support observing campaigns; (2) assist in various science investigations pertinent to the campaign; (3) provide an alert-sounding mechanism should the need arise; (4) immediate outreach and dissemination of results via our media/blogger members; (5) provide a forum for discussions between the imagers and modelers to help strategize the observing campaign for maximum benefit. In 2014, two new comet observing campaigns involving pro-am collaborations have been initiated: (1) C/2013 A1 (C/SidingSpring) and (2) 67P/Churyumov-Gerasimenko (CG), target for ESA/Rosetta mission. The evolving need for individual customized observing campaigns has been incorporated into the evolution of PACA portal that currently is focused on comets: from supporting observing campaigns of current comets, legacy data, historical comets; interconnected with social media and a set of shareable documents addressing observational strategies; consistent standards for data; data access, use, and storage, to align with the needs of professional observers. The integration of science, observations by professional and amateur astronomers, and various social media provides a dynamic and evolving collaborative partnership between professional and amateur astronomers

  7. Geometric optics theory and design of astronomical optical systems using Mathematica

    CERN Document Server

    Romano, Antonio

    2016-01-01

    This text, now in its second edition, presents the mathematical background needed to design many optical combinations that are used in astronomical telescopes and cameras. It uses a novel approach to third-order aberration theory based on Fermat’s principle and the use of particular optical paths (called stigmatic paths) instead of rays, allowing for easier derivation of third-order formulae. Each optical combination analyzed is accompanied by a downloadable Mathematica® notebook that automates its third-order design, eliminating the need for lengthy calculations. The essential aspects of an optical system with an axis of rotational symmetry are introduced first, along with a development of Gaussian optics from Fermat’s principal. A simpler approach to third-order monochromatic aberrations based on both Fermat’s principle and stigmatic paths is then described, followed by a new chapter on fifth-order aberrations and their classification. Several specific optical devices are discussed and analyzed, incl...

  8. Laboratory measurements and astronomical search for cyanomethanimine

    Science.gov (United States)

    Melosso, M.; Melli, A.; Puzzarini, C.; Codella, C.; Spada, L.; Dore, L.; Degli Esposti, C.; Lefloch, B.; Bachiller, R.; Ceccarelli, C.; Cernicharo, J.; Barone, V.

    2018-02-01

    Context. C-cyanomethanimine (HNCHCN), existing in the two Z and E isomeric forms, is a key prebiotic molecule, but, so far, only the E isomer has been detected toward the massive star-forming region Sagittarius B2(N) using transitions in the radio wavelength domain. Aims: With the aim of detecting HNCHCN in Sun-like-star forming regions, the laboratory investigation of its rotational spectrum has been extended to the millimeter-/submillimeter-wave (mm-/submm-) spectral window in which several unbiased spectral surveys have been already carried out. Methods: High-resolution laboratory measurements of the rotational spectrum of C-cyanomethanimine were carried out in the 100-420 GHz range using a frequency-modulation absorption spectrometer. We then searched for the C-cyanomethanimine spectral features in the mm-wave range using the high-sensitivity and unbiased spectral surveys obtained with the IRAM 30-m antenna in the ASAI context, the earliest stages of star formation from starless to evolved Class I objects being sampled. Results: For both the Z and E isomers, the spectroscopic work has led to an improved and extended knowledge of the spectroscopic parameters, thus providing accurate predictions of the rotational signatures up to 700 GHz. So far, no C-cyanomethanimine emission has been detected toward the ASAI targets, and upper limits of the column density of 1011-1012 cm-2 could only be derived. Consequently, the C-cyanomethanimine abundances have to be less than a few 10-10 for starless and hot-corinos. A less stringent constraint, ≤10-9, is obtained for shocks sites. Conclusions: The combination of the upper limits of the abundances of C-cyanomethanimine together with accurate laboratory frequencies up to 700 GHz poses the basis for future higher sensitivity searches around Sun-like-star forming regions. For compact (typically less than 1″) and chemically enriched sources such as hot-corinos, the use of interferometers as NOEMA and ALMA in their extended

  9. La mujer en la astronomía: pasado y presente

    Science.gov (United States)

    Dubner, G.

    There exists a long and honorable tradition of participation of women in astronomy, affording many significant contributions to the field. Historically, however, many of these contributions have remained ignored, or recorded under the names of husbands, brothers or bosses. The present report includes an historical perspective, summarizing some of the most signicant contributions done along the last three centuries by female astronomers. Briefly: Catherina Hevelius (1646-1693), author of the largest and last stars catalog made without the aid of a telescope; Nicole-Reine Lepaute (1723-1788) extraordinary mathematician who predicted the path of Halley's Comet in 1757; Caroline Herschel (1750-1848) assistant of her brother William, discovered 8 comets, reduced the positions to a common epoch and published the catalog of 2500 nebulae observed by her brother, was elected honorary member of the Royal Astronomical Society (RAS); Maria Mitchell (1818-1889), professor of astronomy and director of the Vassar College Observatory, dedicated her life to women's education; Williamina Fleming (1857-1911)discovered 94 of the 107 Wolf-Rayet stars known at her time, the bulk of the first HD catalog was based on her spectral types classification; Annie Cannon (1863-1941) examined and classified nearly 500.000 stars, rearranged Fleming's spectral system, defining the OBAFGKM series; Henrietta Swan Leavitt (1868-1921) worked cataloging variable stars, discovered the period-luminosity relations in Cepheids; Cecilia Payne-Gaposhkin combined observations with theory to obtain a temperature scale for Cannon's spectral types; Ruby Payne-Scott (1912-1981), the first female radioastronomer in the world, developed the theory of aperture synthesis, in which most of the larger radio interferometers are based. The present trends are analized based on statistics of the International Astronomical Union (IAU): women represent 11.8% of the total of IAU members; in Argentina the percentage is 33

  10. Patient-specific scatter correction in clinical cone beam computed tomography imaging made possible by the combination of Monte Carlo simulations and a ray tracing algorithm

    DEFF Research Database (Denmark)

    Slot Thing, Rune; Bernchou, Uffe; Mainegra-Hing, Ernesto

    2013-01-01

    _cbct), was used to perform MC simulations of an Elekta XVI CBCT imaging system. A 60keV x-ray source was used, and air kerma scored at the detector plane. Several variance reduction techniques (VRTs) were used to increase the scatter calculation efficiency. Three patient phantoms based on CT scans were simulated...... being fully implemented in a clinical setting. This study investigates the combination of using fast MC simulations to predict scatter distributions with a ray tracing algorithm to allow calibration between simulated and clinical CBCT images. Material and methods. An EGSnrc-based user code (egs......, namely a brain, a thorax and a pelvis scan. A ray tracing algorithm was used to calculate the detector signal due to primary photons. A total of 288 projections were simulated, one for each thread on the computer cluster used for the investigation. Results. Scatter distributions for the brain, thorax...

  11. DeTeCt 3.0: A software tool to detect impacts of small objects in video observations of Jupiter obtained by amateur astronomers

    Science.gov (United States)

    Juaristi, J.; Delcroix, M.; Hueso, R.; Sánchez-Lavega, A.

    2017-09-01

    Impacts of small size objects (10-20 m in diameter) with Jupiter atmosphere result in luminous superbolides that can be observed from the Earth with small size telescopes. Impacts of this kind have been observed four times by amateur astronomers since July 2010. The probability of observing one of these events is very small. Amateur astronomers observe Jupiter using fast video cameras that record thousands of frames during a few minutes which combine into a single image that generally results in a high-resolution image. Flashes are brief, faint and often lost by image reconstruction software. We present major upgrades in a software tool DeTeCt initially developed by amateur astronomer Marc Delcroix and our current project to maximize the chances of detecting more of these impacts in Jupiter.

  12. Gaussian-Beam/Physical-Optics Design Of Beam Waveguide

    Science.gov (United States)

    Veruttipong, Watt; Chen, Jacqueline C.; Bathker, Dan A.

    1993-01-01

    In iterative method of designing wideband beam-waveguide feed for paraboloidal-reflector antenna, Gaussian-beam approximation alternated with more nearly exact physical-optics analysis of diffraction. Includes curved and straight reflectors guiding radiation from feed horn to subreflector. For iterative design calculations, curved mirrors mathematically modeled as thin lenses. Each distance Li is combined length of two straight-line segments intersecting at one of flat mirrors. Method useful for designing beam-waveguide reflectors or mirrors required to have diameters approximately less than 30 wavelengths at one or more intended operating frequencies.

  13. Eighth Scientific Meeting of the Spanish Astronomical Society

    CERN Document Server

    Diego, Jose M; González-Serrano, J. Ignacio; Gorgas, Javier; Highlights of Spanish Astrophysics V

    2010-01-01

    This volume collects the invited contributions and plenary sessions presented at the Eighth Scientific Meeting of the Spanish Astronomical Society (Sociedad Española de Astronomía, SEA) held on July 7-11, 2008 in Santander. These contributions cover all fields of astronomy and astrophysics, i.e., the Sun and solar system, the galaxy and its components, galaxies and cosmology, observatories and instrumentation, as well as astronomy teaching and dissemination. Further plenary sessions were devoted to selected hot topics, including the exploration of the solar system, gravitational lensing, exoplanets, X-ray binaries, solar magnetism, gravitational waves, the ALHAMBRA collaboration, and the OSIRIS instrument on the new 10-m GTC. Abstracts of the contributions presented at the parallels sessions and posters are also included in the book. Complete versions of those papers are available online.

  14. Astrophysics is easy! an introduction for the amateur astronomer

    CERN Document Server

    Inglis, Mike

    2007-01-01

    With some justification, many amateur astronomers believe astrophysics is a very difficult subject, requiring at least degree-level mathematics to understand it properly. This isn’t necessarily the case. Mike Inglis' quantitative approach to the subject explains all aspects of astrophysics in simple terms and cuts through the incomprehensible mathematics with which this fascinating subject is all too often associated. Astrophysics is Easy! begins by looking at the H-R diagram and other basic tools of astrophysics, then ranges across the universe, from a first look at the interstellar medium and nebulae, through the birth, evolution and death of stars, to the physics of galaxies and clusters of galaxies. A unique feature of this book is the way that Dr. Inglis lists example objects for practical observation at every stage, so that practical astronomers can go and look at the object or objects under discussion – using only easily-available commercial amateur equipment.

  15. Astronomical Correlates of Architecture and Landscape in Mesoamerica

    Science.gov (United States)

    Šprajc, Ivan

    Mesoamerican civic and ceremonial buildings were largely oriented to astronomical phenomena on the horizon, mostly to sunrises and sunsets on particular dates; some orientations were probably intended to mark major lunar standstills and Venus extremes. Solar orientations must have had a practical function, allowing the use of observational calendars that facilitated a proper scheduling of agricultural activities. Moreover, some important buildings seem to have been erected on carefully selected places, with the purpose of employing prominent peaks on the local horizon as natural markers of sunrises and sunsets on relevant dates. However, the characteristics of buildings incorporating deliberate alignments, their predominant clockwise skew from cardinal directions, and their relations to the surrounding natural and cultural landscape reveal that the architectural and urban planning in Mesoamerica was dictated by a complex set of rules, in which astronomical considerations were embedded in a broader framework of cosmological concepts substantiated by political ideology.

  16. On AIPS++, A New Astronomical Information Processing System

    Science.gov (United States)

    Croes, G. A.

    1993-01-01

    The AIPS system that has served the needs of the radio astronomical community remarkably well during the last 15 years, is showing signs of age, and is being replaced by a more modern system, AIPS++. As the name implies AIPS++ will be developed in an object-oriented fashion, and use C++ as its main programming language. The work is being done by a consortium of seven organizations, with coordinated activities worldwide. After a review of the history of the project to this date, from management, astronomical and technical viewpoints and the current state of the project, the paper concentrates on the tradeoffs implied by the choice of implementation style, and the lessons we have learned, good and bad.

  17. Unveiling galaxies the role of images in astronomical discovery

    CERN Document Server

    Roy, Jean-René

    2017-01-01

    Galaxies are known as the building blocks of the universe, but arriving at this understanding has been a thousand-year odyssey. This journey is told through the lens of the evolving use of images as investigative tools. Initial chapters explore how early insights developed in line with new methods of scientific imaging, particularly photography. The volume then explores the impact of optical, radio and x-ray imaging techniques. The final part of the story discusses the importance of atlases of galaxies; how astronomers organised images in ways that educated, promoted ideas and pushed for new knowledge. Images that created confusion as well as advanced knowledge are included to demonstrate the challenges faced by astronomers and the long road to understanding galaxies. By examining developments in imaging, this text places the study of galaxies in its broader historical context, contributing to both astronomy and the history of science.

  18. A Further Survey of Multiple Authorship in the Astronomical Literature

    Science.gov (United States)

    Smith, Graeme H.

    2017-11-01

    Authorship trends within the astronomical community have been studied using data drawn from the publication records of 12 refereed journals. The period covered by the study is 1991-2015. Across all journals, the annual fraction of papers with one or two authors has decreased with time, typically accompanied by an increased propensity for papers to have six or more co-authors. There is considerable variability in the behavior of three-to-five author papers. Reports on instrumentation developments within Publications of the Astronomical Society of the Pacific (PASP), a journal that places specific emphasis on publishing instrumentation papers, have a higher number of authors than average. The trends away from one-to-two author papers and toward papers with six or more authors show no correlation with either the annual number of papers per journal or the geographical diversity of the contributing author pools.

  19. A component based astronomical visualization tool for instrument control

    Science.gov (United States)

    Briegel, Florian; Berwein, Jürgen; Kittmann, Frank; Pavlov, Alexey

    2008-07-01

    For various astronomical instruments developed at the Max-Planck-Institute-Heidelberg there was a need for a highly flexible display and control tool. Many display tools (ximtool, DS9, skycat,...) are available for astronomy, but all this applications are monolitic and can't be easily enriched by plugins for interaction with the graphical display, and other functionalities for remote access and control of the instrument and data pipepline. It was developed on top of Trolltechs Cross-Platform Rich Client Development Framework Qt,1 the modern middleware Internet Communications Engine 2 from ZeroC and the template based SOA developer framework for astronomical instrumentation - NICE.3 The display tool is used on the Calar Alto Observatory, Spain) as a guider, for a wide field imager and guider at the Wise Observatory (Israel; for the LBT interferometer Linc-Nirvana, USA).

  20. Using Modern Technologies to Capture and Share Indigenous Astronomical Knowledge

    Science.gov (United States)

    Nakata, Martin; Hamacher, Duane W.; Warren, John; Byrne, Alex; Pagnucco, Maurice; Harley, Ross; Venugopal, Srikumar; Thorpe, Kirsten; Neville, Richard; Bolt, Reuben

    2014-06-01

    Indigenous Knowledge is important for Indigenous communities across the globe and for the advancement of our general scientific knowledge. In particular, Indigenous astronomical knowledge integrates many aspects of Indigenous Knowledge, including seasonal calendars, navigation, food economics, law, ceremony, and social structure. Capturing, managing, and disseminating this knowledge in the digital environment poses a number of challenges, which we aim to address using a collaborative project emerging between experts in the higher education, library, archive and industry sectors. Using Microsoft's WorldWide Telescope and Rich Interactive Narratives technologies, we propose to develop software, media design, and archival management solutions to allow Indigenous communities to share their astronomical knowledge with the world on their terms and in a culturally sensitive manner.