WorldWideScience

Sample records for radio polarization measurements

  1. Polarized radio emission from extensive air showers measured with LOFAR

    NARCIS (Netherlands)

    Schellart, P.; Buitink, S.; Corstanje, A.; Enriquez, J. E.; Falcke, H.; Hörandel, J. R.; Krause, M.; Nelles, A.; Rachen, J. P.; Scholten, O.; ter Veen, S.; Thoudam, S.; Trinh, T.N.G.

    2014-01-01

    We present LOFAR measurements of radio emission from extensive air showers. We find that this emission is strongly polarized, with a median degree of polarization of nearly 99%, and that the angle between the polarization direction of the electric field and the Lorentz force acting on the particles,

  2. High-frequency radio polarization measurements of WMAP point sources

    CERN Document Server

    Jackson, N; Battye, R A; Gabuzda, D; Taylor, A C

    2009-01-01

    We present polarization measurements at 8.4, 22, and 43 GHz made with the VLA of a complete sample of extragalactic sources stronger than 1 Jy in the 5-year WMAP catalogue and with declinations north of -34 degrees. The observations were motivated by the need to know the polarization properties of radio sources at frequencies of tens of GHz in order to subtract polarized foregrounds for future sensitive Cosmic Microwave Background (CMB) experiments. The total intensity and polarization measurements are generally consistent with comparable VLA calibration measurements for less-variable sources, and within a similar range to WMAP fluxes for unresolved sources. A further paper will present correlations between measured parameters and derive implications for CMB measurements.

  3. Probing the radio emission from air showers with polarization measurements

    Science.gov (United States)

    Aab, A.; Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Antičić, T.; Aramo, C.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Badescu, A. M.; Barber, K. B.; Bardenet, R.; Bäuml, J.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellido, J. A.; BenZvi, S.; Berat, C.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brancus, I.; Brogueira, P.; Brown, W. C.; Buchholz, P.; Bueno, A.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, B.; Caccianiga, L.; Candusso, M.; Caramete, L.; Caruso, R.; Castellina, A.; Cataldi, G.; Cazon, L.; Cester, R.; Cheng, S. H.; Chiavassa, A.; Chinellato, J. A.; Chudoba, J.; Cilmo, M.; Clay, R. W.; Cocciolo, G.; Colalillo, R.; Collica, L.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cooper, M. J.; Coutu, S.; Covault, C. E.; Criss, A.; Cronin, J.; Curutiu, A.; Dallier, R.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; de Jong, S. J.; De La Vega, G.; de Mello Junior, W. J. M.; de Mello Neto, J. R. T.; De Mitri, I.; de Souza, V.; de Vries, K. D.; del Peral, L.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Di Matteo, A.; Diaz, J. C.; Díaz Castro, M. L.; Diep, P. N.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; dos Anjos, J. C.; Dova, M. T.; Ebr, J.; Engel, R.; Erdmann, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Fang, K.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fick, B.; Figueira, J. M.; Filevich, A.; Filipčič, A.; Foerster, N.; Fox, B. D.; Fracchiolla, C. E.; Fraenkel, E. D.; Fratu, O.; Fröhlich, U.; Fuchs, B.; Gaior, R.; Gamarra, R. F.; Gambetta, S.; García, B.; Garcia Roca, S. T.; Garcia-Gamez, D.; Garcia-Pinto, D.; Garilli, G.; Gascon Bravo, A.; Gemmeke, H.; Ghia, P. L.; Giammarchi, M.; Giller, M.; Gitto, J.; Glaser, C.; Glass, H.; Gomez Albarracin, F.; Gómez Berisso, M.; Gómez Vitale, P. F.; Gonçalves, P.; Gonzalez, J. G.; Gookin, B.; Gorgi, A.; Gorham, P.; Gouffon, P.; Grebe, S.; Griffith, N.; Grillo, A. F.; Grubb, T. D.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Hansen, P.; Harari, D.; Harrison, T. A.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Hollon, N.; Holt, E.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huber, D.; Huege, T.; Insolia, A.; Isar, P. G.; Jansen, S.; Jarne, C.; Josebachuili, M.; Kadija, K.; Kambeitz, O.; Kampert, K. H.; Karhan, P.; Kasper, P.; Katkov, I.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapp, J.; Krause, R.; Krohm, N.; Krömer, O.; Kruppke-Hansen, D.; Kuempel, D.; Kunka, N.; La Rosa, G.; LaHurd, D.; Latronico, L.; Lauer, R.; Lauscher, M.; Lautridou, P.; Le Coz, S.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; López, R.; Lopez Agüera, A.; Louedec, K.; Lozano Bahilo, J.; Lu, L.; Lucero, A.; Ludwig, M.; Lyberis, H.; Maccarone, M. C.; Malacari, M.; Maldera, S.; Maller, J.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, V.; Mariş, I. C.; Marquez Falcon, H. R.; Marsella, G.; Martello, D.; Martin, L.; Martinez, H.; Martínez Bravo, O.; Martraire, D.; Masías Meza, J. J.; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurel, D.; Maurizio, D.; Mayotte, E.; Mazur, P. O.; Medina, C.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Messina, S.; Meyhandan, R.; Mićanović, S.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Molina-Bueno, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morales, B.; Morello, C.; Moreno, J. C.; Mostafá, M.; Moura, C. A.; Muller, M. A.; Müller, G.; Münchmeyer, M.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Nhung, P. T.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Nožka, L.; Oehlschläger, J.; Olinto, A.; Oliveira, M.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Parente, G.; Parra, A.; Pastor, S.; Paul, T.; Pech, M.; PeÂķala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Petrera, S.; Petrolini, A.; Petrov, Y.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Pontz, M.; Porcelli, A.; Preda, T.; Privitera, P.; Prouza, M.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Revenu, B.; Ridky, J.; Riggi, S.; Risse, M.; Ristori, P.; Rivera, H.; Rizi, V.; Roberts, J.; Rodrigues de Carvalho, W.; Rodriguez Cabo, I.; Rodriguez Fernandez, G.; Rodriguez Martino, J.; Rodriguez Rojo, J.; Rodríguez-Frías, M. D.; Ros, G.; Rosado, J.; Rossler, T.; Roth, M.; Rouillé-d'Orfeuil, B.; Roulet, E.; Rovero, A. C.; Rühle, C.; Saffi, S. J.; Saftoiu, A.; Salamida, F.; Salazar, H.; Salesa Greus, F.; Salina, G.; Sánchez, F.; Sanchez-Lucas, P.; Santo, C. E.; Santos, E.; Santos, E. M.; Sarazin, F.; Sarkar, B.; Sarmento, R.; Sato, R.; Scharf, N.; Scherini, V.; Schieler, H.; Schiffer, P.; Schmidt, A.; Scholten, O.; Schoorlemmer, H.; Schovánek, P.; Schröder, F. G.; Schulz, A.; Schulz, J.; Sciutto, S. J.; Scuderi, M.; Segreto, A.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sidelnik, I.; Sigl, G.; Sima, O.; Śmiałkowski, A.; Šmída, R.; Snow, G. R.; Sommers, P.; Sorokin, J.; Spinka, H.; Squartini, R.; Srivastava, Y. N.; Stanič, S.; Stapleton, J.; Stasielak, J.; Stephan, M.; Straub, M.; Stutz, A.; Suarez, F.; Suomijärvi, T.; Supanitsky, A. D.; Šuša, T.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Szuba, M.; Tapia, A.; Tartare, M.; Taşcǎu, O.; Thao, N. T.; Tiffenberg, J.; Timmermans, C.; Tkaczyk, W.; Todero Peixoto, C. J.; Toma, G.; Tomankova, L.; Tomé, B.; Tonachini, A.; Torralba Elipe, G.; Torres Machado, D.; Travnicek, P.; Tridapalli, D. B.; Trovato, E.; Tueros, M.; Ulrich, R.; Unger, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van Aar, G.; van den Berg, A. M.; van Velzen, S.; van Vliet, A.; Varela, E.; Vargas Cárdenas, B.; Varner, G.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Verzi, V.; Vicha, J.; Videla, M.; Villaseñor, L.; Wahlberg, H.; Wahrlich, P.; Wainberg, O.; Walz, D.; Watson, A. A.; Weber, M.; Weidenhaupt, K.; Weindl, A.; Werner, F.; Westerhoff, S.; Whelan, B. J.; Widom, A.; Wieczorek, G.; Wiencke, L.; Wilczyńska, B.; Wilczyński, H.; Will, M.; Williams, C.; Winchen, T.; Wundheiler, B.; Wykes, S.; Yamamoto, T.; Yapici, T.; Younk, P.; Yuan, G.; Yushkov, A.; Zamorano, B.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zaw, I.; Zepeda, A.; Zhou, J.; Zhu, Y.; Zimbres Silva, M.; Ziolkowski, M.; Pierre Auger Collaboration

    2014-03-01

    The emission of radio waves from air showers has been attributed to the so-called geomagnetic emission process. At frequencies around 50 MHz this process leads to coherent radiation which can be observed with rather simple setups. The direction of the electric field induced by this emission process depends only on the local magnetic field vector and on the incoming direction of the air shower. We report on measurements of the electric field vector where, in addition to this geomagnetic component, another component has been observed that cannot be described by the geomagnetic emission process. The data provide strong evidence that the other electric field component is polarized radially with respect to the shower axis, in agreement with predictions made by Askaryan who described radio emission from particle showers due to a negative charge excess in the front of the shower. Our results are compared to calculations which include the radiation mechanism induced by this charge-excess process.

  4. Polarized radio emission from extensive air showers measured with LOFAR

    CERN Document Server

    Schellart, P; Corstanje, A; Enriquez, J E; Falcke, H; Hörandel, J R; Krause, M; Nelles, A; Rachen, J P; Scholten, O; ter Veen, S; Thoudam, S; Trinh, T N G

    2014-01-01

    We present LOFAR measurements of radio emission from extensive air showers. We find that this emission is strongly polarized, with a median degree of polarization exceeding $99\\%$, and that the angle between the polarization direction of the electric field and the Lorentz force acting on the particles, depends on the observer location in the shower plane. This can be understood as a superposition of the radially polarized charge-excess emission mechanism, first proposed by Askaryan and the geomagnetic emission mechanism proposed by Kahn and Lerche. We calculate the relative strengths of both contributions, as quantified by the charge-excess fraction, for $179$ individual air showers. We find that the measured charge-excess fraction is higher for air showers arriving from closer to zenith. Furthermore, the measured charge-excess fraction also increases with increasing observer distance from the air shower symmetry axis. The measured values range from $(3.47\\pm 0.79)\\%$ for very inclined air showers at $25\\, \\m...

  5. Radio emission of energetic cosmic ray air showers: Polarization measurements with LOPES

    Energy Technology Data Exchange (ETDEWEB)

    Isar, P.G. [Institut fuer Kernphysik, Forschungszentrum Karlsruhe (Germany)], E-mail: gina.isar@ik.fzk.de; Apel, W.D. [Institut fuer Kernphysik, Forschungszentrum Karlsruhe (Germany); Arteaga, J.C. [Institut fuer Experimentelle Kernphysik, Universitaet Karlsruhe (Germany); Asch, T. [Inst. Prozessdatenverarbeitung und Elektronik, Forschungszentrum Karlsruhe (Germany); Auffenberg, J. [Fachbereich Physik, Universitaet Wuppertal (Germany); Badea, F. [Institut fuer Kernphysik, Forschungszentrum Karlsruhe (Germany); Baehren, L. [Department of Astrophysics, Radboud University Nijmegen (Netherlands); Bekk, K. [Institut fuer Kernphysik, Forschungszentrum Karlsruhe (Germany); Bertaina, M. [Dipartimento di Fisica Generale dell' Universita Torino (Italy); Biermann, P.L. [Max-Planck-Institut fuer Radioastronomie Bonn (Germany); Bluemer, J. [Institut fuer Kernphysik, Forschungszentrum Karlsruhe (Germany); Institut fuer Experimentelle Kernphysik, Universitaet Karlsruhe (Germany); Bozdog, H. [Institut fuer Kernphysik, Forschungszentrum Karlsruhe (Germany); Brancus, I.M. [National Institute of Physics and Nuclear Engineering Bucharest (Romania); Brueggemann, M.; Buchholz, P. [Fachbereich Physik, Universitaet Siegen (Germany); Buitink, S. [Department of Astrophysics, Radboud University Nijmegen (Netherlands); Cantoni, E. [Dipartimento di Fisica Generale dell' Universita Torino (Italy); Istituto di Fisica dello Spazio Interplanetario, INAF Torino (Italy); Chiavassa, A. [Dipartimento di Fisica Generale dell' Universita Torino (Italy); Cossavella, F. [Institut fuer Experimentelle Kernphysik, Universitaet Karlsruhe (Germany); Daumiller, K. [Institut fuer Kernphysik, Forschungszentrum Karlsruhe (Germany)] (and others)

    2009-06-01

    LOPES is a radio antenna array co-located with the Karlsruhe Shower Core and Array DEtector, KASCADE-Grande in Forschungszentrum Karlsruhe, Germany, which provides well-calibrated trigger information and air shower parameters for primary energies up to 10{sup 18}eV. By the end of 2006, the radio antennas were re-configured to perform polarization measurements of the radio signal of cosmic ray air showers, recording in the same time both, the East-West and North-South polarization directions of the radio emission. The main goal of these measurements is to reconstruct the polarization characteristics of the emitted signal. This will allow a detailed comparison with theoretical predictions. The current status of these measurements is reported here.

  6. THE Q/U IMAGING EXPERIMENT: POLARIZATION MEASUREMENTS OF RADIO SOURCES AT 43 AND 95 GHz

    Energy Technology Data Exchange (ETDEWEB)

    Huffenberger, K. M. [Department of Physics, Florida State University, P.O. Box 3064350, Tallahassee, FL 32306-4350 (United States); Araujo, D.; Zwart, J. T. L. [Department of Physics and Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Bischoff, C.; Buder, I. [Kavli Institute for Cosmological Physics, Department of Physics, Enrico Fermi Institute, The University of Chicago, Chicago, IL 60637 (United States); Chinone, Y.; Hasegawa, M. [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Cleary, K. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 E. California Blvd M/C 249-17, Pasadena, CA 91125 (United States); Kusaka, A. [Physics Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Monsalve, R. [School of Earth and Space Exploration, Arizona State University, 781 E. Terrace Road, Tempe, AZ 85287 (United States); Næss, S. K. [Department of Astrophysics, University of Oxford, Keble Road, Oxford, OX1 3RH (United Kingdom); Newburgh, L. B. [Dunlap Institute, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Reeves, R. [CePIA, Departamento de Astronomía, Universidad de Concepción (Chile); Ruud, T. M.; Eriksen, H. K. [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, NO-0315 Oslo (Norway); Wehus, I. K.; Gaier, T. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Dickinson, C. [Jodrell Bank Centre for Astrophysics, Alan Turing Building, School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Gundersen, J. O., E-mail: huffenbe@physics.fsu.edu [Department of Physics, University of Miami, 1320 Campo Sano Drive, Coral Gables, FL 33146 (United States); Collaboration: QUIET Collaboration; and others

    2015-06-10

    We present polarization measurements of extragalactic radio sources observed during the cosmic microwave background polarization survey of the Q/U Imaging Experiment (QUIET), operating at 43 GHz (Q-band) and 95 GHz (W-band). We examine sources selected at 20 GHz from the public, >40 mJy catalog of the Australia Telescope (AT20G) survey. There are ∼480 such sources within QUIET’s four low-foreground survey patches, including the nearby radio galaxies Centaurus A and Pictor A. The median error on our polarized flux density measurements is 30–40 mJy per Stokes parameter. At signal-to-noise ratio > 3 significance, we detect linear polarization for seven sources in Q-band and six in W-band; only 1.3 ± 1.1 detections per frequency band are expected by chance. For sources without a detection of polarized emission, we find that half of the sources have polarization amplitudes below 90 mJy (Q-band) and 106 mJy (W-band), at 95% confidence. Finally, we compare our polarization measurements to intensity and polarization measurements of the same sources from the literature. For the four sources with WMAP and Planck intensity measurements >1 Jy, the polarization fractions are above 1% in both QUIET bands. At high significance, we compute polarization fractions as much as 10%–20% for some sources, but the effects of source variability may cut that level in half for contemporaneous comparisons. Our results indicate that simple models—ones that scale a fixed polarization fraction with frequency—are inadequate to model the behavior of these sources and their contributions to polarization maps.

  7. The Q/U Imaging Experiment: Polarization Measurements of Radio Sources at 43 and 95 GHz

    CERN Document Server

    Huffenberger, K M; Bischoff, C; Buder, I; Chinone, Y; Cleary, K; Kusaka, A; Monsalve, R; Næss, S K; Newburgh, L B; Reeves, R; Ruud, T M; Wehus, I K; Zwart, J T L; Dickinson, C; Eriksen, H K; Gaier, T; Gundersen, J O; Hasegawa, M; Hazumi, M; Miller, A D; Radford, S J E; Readhead, A C S; Staggs, S T; Tajima, O; Thompson, K L

    2014-01-01

    We present polarization measurements of extragalactic radio sources observed during the Cosmic Microwave Background polarization survey of the Q/U Imaging Experiment (QUIET), operating at 43 GHz (Q-band) and 95 GHz (W-band). We examine sources selected at 20 GHz from the public, $>$40 mJy catalog of the Australia Telescope (AT20G) survey. There are $\\sim$480 such sources within QUIET's four low-foreground survey patches, including the nearby radio galaxies Centaurus A and Pictor A. The median error on our polarized flux density measurements is 30--40 mJy per Stokes parameter. At S/N $> 3$ significance, we detect linear polarization for seven sources in Q-band and six in W-band; only $1.3 \\pm 1.1$ detections per frequency band are expected by chance. For sources without a detection of polarized emission, we find that half of the sources have polarization amplitudes below 90 mJy (Q-band) and 106 mJy (W-band), at 95% confidence. Finally, we compare our polarization measurements to intensity and polarization meas...

  8. Polarization Methods of Measuring the Roll Angle of an Object in Motion in Radio Beacon Navigation Systems

    Science.gov (United States)

    Gulko, V. L.; Mescheryakov, A. A.

    2016-06-01

    Polarization methods of measuring the roll angle of an object in motion with the help of radio beacon systems are considered. The polarization properties of the beacon signals received on board the object and amplitude-phase processing of their orthogonal polarized components are used to accomplish this goal.

  9. Measurement of the circular polarization in radio emission from extensive air showers confirms emission mechanisms

    CERN Document Server

    Scholten, O; Bonardi, A; Buitink, S; Correa, P; Corstanje, A; Hasankiadeh, Q Dorosti; Falcke, H; Hörandel, J R; Mitra, P; Mulrey, K; Nelles, A; Rachen, J P; Rossetto, L; Schellart, P; Thoudam, S; ter Veen, S; de Vries, K D; Winchen, T

    2016-01-01

    We report here on a novel analysis of the complete set of four Stokes parameters that uniquely determine the linear and/or circular polarization of the radio signal for an extensive air shower. The observed dependency of the circular polarization on azimuth angle and distance to the shower axis is a clear signature of the interfering contributions from two different radiation mechanisms, a main contribution due to a geomagnetically-induced transverse current and a secondary component due to the build-up of excess charge at the shower front. The data, as measured at LOFAR, agree very well with a calculation from first principles. This opens the possibility to use circular polarization as an investigative tool in the analysis of air shower structure, such as for the determination of atmospheric electric fields.

  10. Measurement of the circular polarization in radio emission from extensive air showers confirms emission mechanisms

    Science.gov (United States)

    Scholten, O.; Trinh, T. N. G.; Bonardi, A.; Buitink, S.; Correa, P.; Corstanje, A.; Dorosti Hasankiadeh, Q.; Falcke, H.; Hörandel, J. R.; Mitra, P.; Mulrey, K.; Nelles, A.; Rachen, J. P.; Rossetto, L.; Schellart, P.; Thoudam, S.; ter Veen, S.; de Vries, K. D.; Winchen, T.

    2016-11-01

    We report here on a novel analysis of the complete set of four Stokes parameters that uniquely determine the linear and/or circular polarization of the radio signal for an extensive air shower. The observed dependency of the circular polarization on azimuth angle and distance to the shower axis is a clear signature of the interfering contributions from two different radiation mechanisms, a main contribution due to a geomagnetically-induced transverse current and a secondary component due to the build-up of excess charge at the shower front. The data, as measured at LOFAR, agree very well with a calculation from first principles. This opens the possibility to use circular polarization as an investigative tool in the analysis of air shower structure, such as for the determination of atmospheric electric fields.

  11. Gain and Polarization Properties of a Large Radio Telescope from Calculation and Measurement: The John A. Galt Telescope

    CERN Document Server

    Du, Xuan; Robishaw, Timothy; Gray, Andrew D; Douglas, Kevin A; Wolleben, Maik

    2016-01-01

    Measurement of the brightness temperature of extended radio emission demands knowledge of the gain (or aperture efficiency) of the telescope and measurement of the polarized component of the emission requires correction for the conversion of unpolarized emission from sky and ground to apparently polarized signal. Radiation properties of the John A. Galt Telescope at the Dominion Radio Astrophysical Observatory were studied through analysis and measurement in order to provide absolute calibration of a survey of polarized emission from the entire northern sky from 1280 to 1750 MHz, and to understand the polarization performance of the telescope. Electromagnetic simulators CST and GRASP-10 were used to compute radiation patterns of the telescope in all Stokes parameters, and aperture efficiency. Aperture efficiency was also evaluated using geometrical optics and was measured using Cyg A. Measured aperture efficiency varied smoothly with frequency between values of 0.49 and 0.54; GRASP-10 yielded values 6.5% high...

  12. Polarization-Modulation Method of Measuring the Bearing of a Moving Object From Orthogonal Elliptically Polarized Signals of a Radio Beacon

    Science.gov (United States)

    Gulko, V. L.; Mescheryakov, A. A.

    2017-05-01

    A polarization-modulation method of estimating the bearing of a moving object using a radio beacon transmitting two mutually orthogonal elliptically polarized radio signals is considered. The signals received onboard the moving object are subject to polarization modulation. The bearing is estimated at the output from a single-channel receiver at the frequency multiple to the polarization modulation frequency.

  13. A new method of measuring radio source parameters of a partially polarized distributed source from spacecraft observations

    Science.gov (United States)

    Manning, R.; Fainberg, J.

    1980-01-01

    An experimental system is analyzed which is designed to determine the angular and polarization properties of low frequency radio sources from measurements made on a spinning spacecraft. The system has been optimized to provide high accuracies for sources at high as well as low elevation angles. Theoretical expressions are derived for the response of this system to a partially polarized point source. Integrations are then carried out to get the system response to a uniform circular distributed source. Data processing techniques are derived so that computer simulations can be carried out to investigate the accuracy of this technique. It is shown that using 24 measurements of a partially polarized source (with Q = U = V = 0.5), taken in one spacecraft rotation, the resulting rms errors in angular position are less than one degree and the errors in determining the Stokes parameters are generally 1-10% for a wide range of source elevations.

  14. A novel method for the evaluation of polarization and hemisphere coverage of HF radio noise measurement antennas

    NARCIS (Netherlands)

    Witvliet, Ben A.; van Maanen, Erik; Bentum, Marinus Jan; Slump, Cornelis H.; Schiphorst, Roelof

    2015-01-01

    In HF (3-30 MHz) communications the ambient electromagnetic background noise or 'radio noise' generally is the limiting factor in reception. Radio noise measurements are needed for spectrum pollution control and to provide reference levels for radio system design. This article discusses the influenc

  15. A novel method for the evaluation of polarization and hemisphere coverage of HF radio noise measurement antennas

    NARCIS (Netherlands)

    Witvliet, Ben A.; van Maanen, Erik; Bentum, Marinus Jan; Slump, Cornelis H.; Schiphorst, Roelof

    2015-01-01

    In HF (3-30 MHz) communications the ambient electromagnetic background noise or 'radio noise' generally is the limiting factor in reception. Radio noise measurements are needed for spectrum pollution control and to provide reference levels for radio system design. This article discusses the

  16. Polarized radio emission from a magnetar

    NARCIS (Netherlands)

    Kramer, M.; Stappers, B.W.; Jessner, A.; Lyne, A.G.; Jordan, C.A.

    2007-01-01

    We present polarization observations of the radio emitting magnetar AXPJ1810-197. Using simultaneous multifrequency observations performed at 1.4, 4.9 and 8.4 GHz, we obtained polarization information for single pulses and the average pulse profile at several epochs. We find that in several respects

  17. The effect of plasma density structure on HF radio wave propagation at auroral and polar latitudes measured by e-POP

    Science.gov (United States)

    Perry, G. W.; James, H. G.; Gillies, R.; McWilliams, K. A.; St-Maurice, J. P.; Yau, A. W.

    2015-12-01

    One of the scientific objectives of the enhanced Polar Outflow Probe (e-POP) Radio Receiver Instrument (RRI) is to study ionospheric density structure and its impact on High Frequency (HF) radio wave propagation. We present a survey of several ePOP RRI transits through isolated beams of the Super Dual Auroral Radar Network (SuperDARN) Saskatoon and Rankin Inlet radars. It reveals that the spreading of a SuperDARN beam beyond its nominal azimuthal beam width of 3.24° is a common occurrence at auroral and polar latitudes. Furthermore, on multiple occasions, lateral deviations of a beam's power peak by several beam widths was measured, indicating the presence of significant plasma density gradients along the ray path. The e-POP RRI measurements illustrate that our understanding and recognition of plasma density gradients and their influence on HF radio wave propagation is limited. We report on the results of employing HF ray tracing techniques to quantify the impact of ionospheric structuring on HF radio wave propagation, and consider the source of the gradients contributing to the spreading of the SuperDARN beams.

  18. Measurements of distributed polarized radio sources from spinning spacecraft - Effect of a tilted axial antenna ISEE-3 application and results

    Science.gov (United States)

    Fainberg, J.; Hoang, S.; Manning, R.

    1985-01-01

    An analysis is presented of the system response of a satellite receiver-antenna system to locate a radio source when the satellite is tilted on its axis. The satellite is spin stabilized but experiences a tilt due to either a mechanical misalignment or a shift in the electrical axis caused by parasitic currents in other spacecraft structures. The shorter the antenna, the more significant the effects. Numerical techniques are developed for obtaining the Stokes parameters and the angular parameters of a uniform conical source sensed by a linear antenna in order to derive the average power response of a synthesized dipole to a point on a distributed polarized source. Relative gains are calculated along the antenna at different angles to the source. The techniques are applied to sample ISEE-3 satellite data for Type III solar radio bursts which were sensed by an axial and an equatorial antenna. The two antennas permit localization of the source and quantification of the polarization and angular extent of the source. The resulting high precision in calculations of all three source parameters commends use of the model in analyses of data from the planned ULYSSES mission.

  19. Imaging Interplanetary CMEs at Radio Frequency From Solar Polar Orbit

    Science.gov (United States)

    Wu, Ji; Sun, Weiying; Zheng, Jianhua; Zhang, Cheng; Wang, Chi; Wang, C. B.; Wang, S.

    Coronal mass ejections (CMEs) are violent discharges of plasma and magnetic fields from the Sun's corona. They have come to be recognized as the major driver of physical conditions in the Sun-Earth system. Consequently, the detection of CMEs is important for un-derstanding and ultimately predicting space weather conditions. The Solar Polar Orbit Radio Telescope (SPORT) is a proposed mission to observe the propagation of interplanetary CMEs from solar polar orbit. The main payload (radio telescope) on board SPORT will be an in-terferometric imaging radiometer working at the meter wavelength band, which will follow the propagation of interplanetary CMEs from a distance of a few solar radii to near 1 AU from solar polar orbit. The SPORT spacecraft will also be equipped with a set of optical and in situ measurement instruments such as a EUV solar telescope, a solar wind plasma experiment, a solar wind ion composition instrument, an energetic particle detector, a wave detector, a mag-netometer and an interplanetary radio burst tracker. In this paper, we first describe the current shortage of interplanetary CME observations. Next, the scientific motivation and objectives of SPORT are introduced. We discuss the basic specifications of the main radio telescope of SPORT with reference to the radio emission mechanisms and the radio frequency band to be observed. Finally, we discuss the key technologies of the SPORT mission, including the con-ceptual design of the main telescope, the image retrieval algorithm and the solar polar orbit injection. Other payloads and their respective observation objectives are also briefly discussed. Key words: Interplanetary CMEs; Interferometric imaging; Solar polar orbit; Radiometer.

  20. Site Evaluation and RFI spectrum measurements in Portugal at the frequency range 0.408-10 GHz for a GEM polarized galactic radio emission experiment

    CERN Document Server

    Fonseca, R; Cupido, L; dos Santos, D M; Smoot, G F; Tello, C A S

    2004-01-01

    We probed for Radio Frequency Interference (RFI) for the three potential Galactic Emission Mapping Experiment (GEM) sites at Portugal using custom made omnidirectional disconic antennas. For the installation of a 10-meter dish dedicated to the mapping of Polarized Galactic Emission foreground planned for 2005-2007 in the 5-10 GHz band, the three sites chosen as suitable to host the antenna were surveyed for local radio pollution in the frequency range [0.01-10] GHz. Tests were done to look for radio broadcasting and mobile phone emission lines in the radio spectrum. The results show one of the sites to be almost entirely RFI clean and showing good conditions to host the experiment.

  1. Extracting Spectral Index of Intergalactic Magnetic Field from Radio Polarizations

    CERN Document Server

    Tiwari, Prabhakar

    2015-01-01

    We explain the large scale correlations in radio polarization in terms of the correlations of primordial/source magnetic field. The radio waves are dominantly produced by the synchrotron mechanism and hence their polarization angle is deemed to be correlated with the magnetic field of the radio source. The primordial intergalactic magnetic field seeds the source magnetic field and hence it is possible that during the source evolution the correlations of primordial magnetic field survived. We model the intergalactic magnetic field in all $3D$ space and fit its correlations with JVAS/CLASS radio polarization alignments. We find that the radio polarization alignments are best fitted with the magnetic field spectral index given by $-2.43\\pm 0.02$. We show that primordial magnetic field correlation provides a good explanation of the observed radio polarization alignment.

  2. Degree of Polarization and Source Counts of Faint Radio Sources from Stacking Polarized Intensity

    OpenAIRE

    Stil, J. M.; Keller, B. W.; George, S. J.; Taylor, A.R.

    2014-01-01

    We present stacking polarized intensity as a means to study the polarization of sources that are too faint to be detected individually in surveys of polarized radio sources. Stacking offers not only high sensitivity to the median signal of a class of radio sources, but also avoids a detection threshold in polarized intensity, and therefore an arbitrary exclusion of source with a low percentage of polarization. Correction for polarization bias is done through a Monte Carlo analysis and tested ...

  3. Radio polarization study in protostellar jet

    CERN Document Server

    Cécere, Mariana; Araudo, Anabella T; De Colle, Fabio; Esquivel, Alejandro; Carrasco-González, Carlos; Rodríguez, Luis F

    2015-01-01

    Synchrotron radiation is commonly observed associated with shocks of different velocities, ranging from relativistic shocks associated with, e.g., active galactic nuclei, gamma-ray bursts or microquasars to weakly- or non-relativistic flows as those observed e.g. in supernovae and supernova remnants. Recent observations of polarization in protostellar jets are important not only because they extend the range over which the acceleration process works, but also because they allow to measure directly the jet and interstellar magnetic field structure and intensity, thus giving insights on the jet ejection mechanism itself. In this paper, we compute for the first time polarized (synchrotron) and non polarized (thermal-X-ray) synthetic emission maps from axisymmetrical simulations of magnetized protostellar jets. We consider models with different jet velocities and variability, as well as models with toroidal or helical magnetic field. Our simulations show that variable, low-density jets with velocities ~ 1000km/s ...

  4. Directional Statistics for Polarization Observations of Individual Pulses from Radio Pulsars

    CERN Document Server

    McKinnon, M M

    2010-01-01

    Radio polarimetry is a three-dimensional statistical problem. The three-dimensional aspect of the problem arises from the Stokes parameters Q, U, and V, which completely describe the polarization of electromagnetic radiation and conceptually define the orientation of a polarization vector in the Poincar'e sphere. The statistical aspect of the problem arises from the random fluctuations in the source-intrinsic polarization and the instrumental noise. A simple model for the polarization of pulsar radio emission has been used to derive the three-dimensional statistics of radio polarimetry. The model is based upon the proposition that the observed polarization is due to the incoherent superposition of two, highly polarized, orthogonal modes. The directional statistics derived from the model follow the Bingham-Mardia and Fisher family of distributions. The model assumptions are supported by the qualitative agreement between the statistics derived from it and those measured with polarization observations of the ind...

  5. Canals in Milky Way radio polarization maps

    CERN Document Server

    Fletcher, A; Fletcher, Andrew; Shukurov, Anvar

    2006-01-01

    Narrow depolarized canals are common in maps of the polarized synchrotron emission of the Milky Way. Two physical effects that can produce these canals have been identified: the presence of Faraday rotation measure ($\\RM$) gradients in a foreground screen and the cumulative cancellation of polarization known as differential Faraday rotation. We show that the behaviour of the Stokes parameters $Q$ and $U$ in the vicinity of a canal can be used to identify its origin. In the case of canals produced by a Faraday screen we demonstrate that, if the polarization angle changes by $90\\degr$ across the canal, as is observed in all fields to-date, the gradients in $\\RM$ must be discontinuous. Shocks are an obvious source of such discontinuities and we derive a relation of the expected mean separation of canals to the abundance and Mach number of supernova driven shocks, and compare this with recent observations by \\citet{Haverkorn03}. We also predict the existence of less common canals with polarization angle changes o...

  6. Radio-frequency Attenuation Length, Basal-Reflectivity, Depth, and Polarization Measurements from Moore's Bay in the Ross Ice-Shelf

    CERN Document Server

    Barwick, S W; Besson, D; Duffin, T; Hanson, J C; Klein, S R; Kleinfelder, S A; Reed, C; Roumi, M; Stezelberger, T; Tatar, J; Walker, J; Zou, L

    2014-01-01

    Radio-glaciological parameters from Moore's Bay, in the Ross Ice Shelf, have been measured. The thickness of the ice shelf in Moore's Bay was measured from reflection times of radio-frequency pulses propagating vertically through the shelf and reflecting from the ocean. The average depth obtained is $576\\pm8$ m. The temperature-averaged attenuation length of the ice column, $\\langle L \\rangle$, is derived from the returned power assuming 100\\% reflection. A linear fit to the data yields $\\langle L(\

  7. Radio propagation measurement and channel modelling

    CERN Document Server

    Salous, Sana

    2013-01-01

    While there are numerous books describing modern wireless communication systems that contain overviews of radio propagation and radio channel modelling, there are none that contain detailed information on the design, implementation and calibration of radio channel measurement equipment, the planning of experiments and the in depth analysis of measured data. The book would begin with an explanation of the fundamentals of radio wave propagation and progress through a series of topics, including the measurement of radio channel characteristics, radio channel sounders, measurement strategies

  8. Relation between Radio Polarization and Spectral Index of Blazars

    Indian Academy of Sciences (India)

    Yuhai Yuan

    2014-09-01

    University Michigan RAdio Observatory (UMRAO) supply many radio photometries and polarimetries. We select a sample of 81 blazars from UMRAO and analyse the correlations between their spectral index and polarizations. Out of 35 BL Lacs and 46 FSRQs in the sample, 8 and 15 show strong correlation.

  9. On the high frequency polarization of pulsar radio emission

    CERN Document Server

    Von Hoensbroech, A; Krawczyk, A

    1998-01-01

    We have analyzed the polarization properties of pulsars at an observing frequency of 4.9 GHz. Together with low frequency data, we are able to trace polarization profiles over more than three octaves into an interesting frequency regime. At those high frequencies the polarization properties often undergo important changes such as significant depolarization. A detailed analysis allowed us to identify parameters, which regulate those changes. A significant correlation was found between the integrated degree of polarization and the loss of rotational energy E^dot. The data were also used to review the widely established pulsar profile classification scheme of core- and cone-type beams. We have discovered the existence of pulsars which show a strongly increasing degree of circular polarization towards high frequencies. Previously unpublished average polarization profiles, recorded at the 100m Effelsberg radio telescope, are presented for 32 radio pulsars at 4.9 GHz. The data were used to derive polarimetric param...

  10. A polarized fast radio burst at low Galactic latitude

    Science.gov (United States)

    Petroff, E.; Burke-Spolaor, S.; Keane, E. F.; McLaughlin, M. A.; Miller, R.; Andreoni, I.; Bailes, M.; Barr, E. D.; Bernard, S. R.; Bhandari, S.; Bhat, N. D. R.; Burgay, M.; Caleb, M.; Champion, D.; Chandra, P.; Cooke, J.; Dhillon, V. S.; Farnes, J. S.; Hardy, L. K.; Jaroenjittichai, P.; Johnston, S.; Kasliwal, M.; Kramer, M.; Littlefair, S. P.; Macquart, J. P.; Mickaliger, M.; Possenti, A.; Pritchard, T.; Ravi, V.; Rest, A.; Rowlinson, A.; Sawangwit, U.; Stappers, B.; Sullivan, M.; Tiburzi, C.; van Straten, W.; ANTARES Collaboration; Albert, A.; André, M.; Anghinolfi, M.; Anton, G.; Ardid, M.; Aubert, J.-J.; Avgitas, T.; Baret, B.; Barrios-Martí, J.; Basa, S.; Bertin, V.; Biagi, S.; Bormuth, R.; Bourret, S.; Bouwhuis, M. C.; Bruijn, R.; Brunner, J.; Busto, J.; Capone, A.; Caramete, L.; Carr, J.; Celli, S.; Chiarusi, T.; Circella, M.; Coelho, J. A. B.; Coleiro, A.; Coniglione, R.; Costantini, H.; Coyle, P.; Creusot, A.; Deschamps, A.; de Bonis, G.; Distefano, C.; di Palma, I.; Donzaud, C.; Dornic, D.; Drouhin, D.; Eberl, T.; El Bojaddaini, I.; Elsässer, D.; Enzenhöfer, A.; Felis, I.; Fusco, L. A.; Galatà, S.; Gay, P.; Geißelsöder, S.; Geyer, K.; Giordano, V.; Gleixner, A.; Glotin, H.; Grégoire, T.; Gracia-Ruiz, R.; Graf, K.; Hallmann, S.; van Haren, H.; Heijboer, A. J.; Hello, Y.; Hernández-Rey, J. J.; Hößl, J.; Hofestädt, J.; Hugon, C.; Illuminati, G.; James, C. W.; de Jong, M.; Jongen, M.; Kadler, M.; Kalekin, O.; Katz, U.; Kießling, D.; Kouchner, A.; Kreter, M.; Kreykenbohm, I.; Kulikovskiy, V.; Lachaud, C.; Lahmann, R.; Lefèvre, D.; Leonora, E.; Lotze, M.; Loucatos, S.; Marcelin, M.; Margiotta, A.; Marinelli, A.; Martínez-Mora, J. A.; Mathieu, A.; Mele, R.; Melis, K.; Michael, T.; Migliozzi, P.; Moussa, A.; Mueller, C.; Nezri, E.; Pǎvǎlaş, G. E.; Pellegrino, C.; Perrina, C.; Piattelli, P.; Popa, V.; Pradier, T.; Quinn, L.; Racca, C.; Riccobene, G.; Roensch, K.; Sánchez-Losa, A.; Saldaña, M.; Salvadori, I.; Samtleben, D. F. E.; Sanguineti, M.; Sapienza, P.; Schnabel, J.; Seitz, T.; Sieger, C.; Spurio, M.; Stolarczyk, Th.; Taiuti, M.; Tayalati, Y.; Trovato, A.; Tselengidou, M.; Turpin, D.; Tönnis, C.; Vallage, B.; Vallée, C.; van Elewyck, V.; Vivolo, D.; Vizzoca, A.; Wagner, S.; Wilms, J.; Zornoza, J. D.; Zúñiga, J.; H.E.S.S. Collaboration; Abdalla, H.; Abramowski, A.; Aharonian, F.; Ait Benkhali, F.; Akhperjanian, A. G.; Andersson, T.; Angüner, E. O.; Arrieta, M.; Aubert, P.; Backes, M.; Balzer, A.; Barnard, M.; Becherini, Y.; Tjus, J. Becker; Berge, D.; Bernhard, S.; Bernlöhr, K.; Blackwell, R.; Böttcher, M.; Boisson, C.; Bolmont, J.; Bordas, P.; Bregeon, J.; Brun, F.; Brun, P.; Bryan, M.; Bulik, T.; Capasso, M.; Casanova, S.; Cerruti, M.; Chakraborty, N.; Chalme-Calvet, R.; Chaves, R. C. G.; Chen, A.; Chevalier, J.; Chrétien, M.; Colafrancesco, S.; Cologna, G.; Condon, B.; Conrad, J.; Cui, Y.; Davids, I. D.; Decock, J.; Degrange, B.; Deil, C.; Devin, J.; Dewilt, P.; Dirson, L.; Djannati-Ataï, A.; Domainko, W.; Donath, A.; Drury, L. O'c.; Dubus, G.; Dutson, K.; Dyks, J.; Edwards, T.; Egberts, K.; Eger, P.; Ernenwein, J.-P.; Eschbach, S.; Farnier, C.; Fegan, S.; Fernandes, M. V.; Fiasson, A.; Fontaine, G.; Förster, A.; Funk, S.; Füßling, M.; Gabici, S.; Gajdus, M.; Gallant, Y. A.; Garrigoux, T.; Giavitto, G.; Giebels, B.; Glicenstein, J. F.; Gottschall, D.; Goyal, A.; Grondin, M.-H.; Hadasch, D.; Hahn, J.; Haupt, M.; Hawkes, J.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hervet, O.; Hinton, J. A.; Hofmann, W.; Hoischen, C.; Holler, M.; Horns, D.; Ivascenko, A.; Jacholkowska, A.; Jamrozy, M.; Janiak, M.; Jankowsky, D.; Jankowsky, F.; Jingo, M.; Jogler, T.; Jouvin, L.; Jung-Richardt, I.; Kastendieck, M. A.; Katarzyński, K.; Kerszberg, D.; Khélifi, B.; Kieffer, M.; King, J.; Klepser, S.; Klochkov, D.; Kluźniak, W.; Kolitzus, D.; Komin, Nu.; Kosack, K.; Krakau, S.; Kraus, M.; Krayzel, F.; Krüger, P. P.; Laffon, H.; Lamanna, G.; Lau, J.; Lees, J.-P.; Lefaucheur, J.; Lefranc, V.; Lemière, A.; Lemoine-Goumard, M.; Lenain, J.-P.; Leser, E.; Lohse, T.; Lorentz, M.; Liu, R.; López-Coto, R.; Lypova, I.; Marandon, V.; Marcowith, A.; Mariaud, C.; Marx, R.; Maurin, G.; Maxted, N.; Mayer, M.; Meintjes, P. J.; Meyer, M.; Mitchell, A. M. W.; Moderski, R.; Mohamed, M.; Mohrmann, L.; Morâ, K.; Moulin, E.; Murach, T.; de Naurois, M.; Niederwanger, F.; Niemiec, J.; Oakes, L.; O'Brien, P.; Odaka, H.; Öttl, S.; Ohm, S.; Ostrowski, M.; Oya, I.; Padovani, M.; Panter, M.; Parsons, R. D.; Pekeur, N. W.; Pelletier, G.; Perennes, C.; Petrucci, P.-O.; Peyaud, B.; Piel, Q.; Pita, S.; Poon, H.; Prokhorov, D.; Prokoph, H.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raab, S.; Reimer, A.; Reimer, O.; Renaud, M.; Reyes, R. De Los; Rieger, F.; Romoli, C.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Rulten, C. B.; Sahakian, V.; Salek, D.; Sanchez, D. A.; Santangelo, A.; Sasaki, M.; Schlickeiser, R.; Schulz, A.; Schüssler, F.; Schwanke, U.; Schwemmer, S.; Settimo, M.; Seyffert, A. S.; Shafi, N.; Shilon, I.; Simoni, R.; Sol, H.; Spanier, F.; Spengler, G.; Spies, F.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Stycz, K.; Sushch, I.; Tavernet, J.-P.; Tavernier, T.; Taylor, A. M.; Terrier, R.; Tibaldo, L.; Tiziani, D.; Tluczykont, M.; Trichard, C.; Tuffs, R.; Uchiyama, Y.; Walt, D. J. Van Der; van Eldik, C.; van Rensburg, C.; van Soelen, B.; Vasileiadis, G.; Veh, J.; Venter, C.; Viana, A.; Vincent, P.; Vink, J.; Voisin, F.; Völk, H. J.; Vuillaume, T.; Wadiasingh, Z.; Wagner, S. J.; Wagner, P.; Wagner, R. M.; White, R.; Wierzcholska, A.; Willmann, P.; Wörnlein, A.; Wouters, D.; Yang, R.; Zabalza, V.; Zaborov, D.; Zacharias, M.; Zanin, R.; Zdziarski, A. A.; Zech, A.; Zefi, F.; Ziegler, A.; Żywucka, N.

    2017-08-01

    We report on the discovery of a new fast radio burst (FRB), FRB 150215, with the Parkes radio telescope on 2015 February 15. The burst was detected in real time with a dispersion measure (DM) of 1105.6 ± 0.8 pc cm-3, a pulse duration of 2.8^{+1.2}_{-0.5} ms, and a measured peak flux density assuming that the burst was at beam centre of 0.7^{+0.2}_{-0.1} Jy. The FRB originated at a Galactic longitude and latitude of 24.66°, 5.28° and 25° away from the Galactic Center. The burst was found to be 43 ± 5 per cent linearly polarized with a rotation measure (RM) in the range -9 magnetic field reversals along the line of sight, a decreased total electron column density from the Milky Way, or some combination of these effects. A lower Galactic DM contribution might explain why this burst was detectable whereas previous searches at low latitude have had lower detection rates than those out of the plane.

  11. Cancer versus FM radio polarization types.

    Science.gov (United States)

    Hallberg, Örjan

    2016-07-01

    In 2002, a detailed analysis of skin melanoma in 289 Swedish municipalities showed a strong association with the number of horizontally polarized main FM transmitters covering a municipality. Basic antenna theory says that body-resonance and standing waves cannot appear above a metal spring mattress unless the electric field is horizontally polarized. To test the hypothesis that body-resonant radiation can cause increased cancer risk in other European countries, I collected and analysed reported data from 24 countries, among which six were using vertical polarization. The results showed a strong association between cancer risk and the use of horizontally polarized FM broadcasting radiation, whereas vertical polarization seemed to cause no health effects. This information should form the basis for initiating relevant corrective actions by responsible authorities.

  12. Measuring Polarization with DASI

    CERN Document Server

    Leitch, E M; Pryke, C L; Reddall, B; Sandberg, E S; Dragovan, M; Carlstrom, J E; Halverson, N W; Holzapfel, W L

    2002-01-01

    We describe an experiment to measure the polarization of the Cosmic Microwave Background (CMB) with the Degree Angular Scale Interferometer (DASI), a compact microwave interferometer optimized to detect CMB anisotropy at multipoles 140 to 900. The telescope has operated at the Amundsen-Scott South Pole research station since 2000 January. The telescope was retrofit as a polarimeter during the 2000--2001 austral summer, and throughout the 2001 and 2002 austral winters has made observations of the CMB with sensitivity to all four Stokes parameters. The telescope performance has been extensively characterized through observations of artificial sources, the Moon, and polarized and unpolarized Galactic sources. In 271 days of observation, DASI has differenced the CMB fluctuations in two fields to an rms noise level of 2.8 uK.

  13. Radio polarization characteristics of two RS CVn binaries

    Science.gov (United States)

    Mutel, R. L.; Lestrade, J.-F.; Doiron, D. J.

    1985-07-01

    The authors report the results of multifrequency epoch VLA observations of polarized radio emission from the nearby active RS CVn binaries UX Arietis and HR 1099. For both systems, there is an excellent correlation between handedness of circular polarization and frequency. Helicity reversal is almost always seen between 1.4 and 5.0 GHz, possibly due to optical depth effects. There may also be an anticorrelation between total intensity and fractional circular polarization, especially at 5 GHz. This is consistent with models in which intense flares are associated with compact self-absorbed synchrotron sources, while the quiescent emission arises from larger gyrosynchrotron-emitting plasma.

  14. Color and Polarization Models of High Redshift Radio Galaxies

    Science.gov (United States)

    Chambers, K. C.

    2000-05-01

    The scattering of an anisotropic quasar beam by dust swept-up by a bipolar outflow is used to construct model color and polarization images for comparison with high redshift radio galaxies and quasars. The swept-up shell is assumed to be optically thin to dust scattering outside the nuclear region. The spectral energy distributions and polarization characteristics of the extended aligned emission from HZRGs and QSRs can be reproduced using an input quasar spectrum and the Loar & Draine (1993) silicate-graphite grain model.

  15. Polarization measurement in the COMPASS polarized target

    CERN Document Server

    Kondo, K; Baum, G; Berglund, P; Doshita, N; Gautheron, F; Görtz, S; Hasegawa, T; Horikawa, N; Ishimoto, S; Iwata, T; Kisselev, Yu V; Koivuniemi, J H; Le Goff, J M; Magnon, A; Meyer, W; Reicherz, G; Matsuda, T

    2004-01-01

    Continuous wave nuclear magnetic resonance (NMR) is used to determine the target polarization in the COMPASS experiment. The system is made of the so-called Liverpool Q-meters, Yale-cards, and VME modules for data taking and system controlling. In 2001 the NMR coils were embedded in the target material, while in 2002 and 2003 the coils were mounted on the outer surface of the target cells to increase the packing factor of the material. Though the error of the measurement became larger with the outer coils than with the inner coils, we have performed stable measurements throughout the COMPASS run time for 3 years. The maximum polarization was +57% and -53% as the average in the target cells.

  16. A giant radio jet of very unusual polarization in a single-lobed radio galaxy

    CERN Document Server

    Bagchi, Joydeep; Krause, Marita; Konar, Chiranjib; Joshi, Santosh

    2009-01-01

    We report the discovery of a very unusual, predominantly one-sided radio galaxy CGCG049-033. Its radio jet, the largest detected so far, emits strongly polarized synchrotron radiation and can be traced all the way from the galactic nucleus to the hot spot located ~440 kpc away. This jet emanates from an extremely massive black-hole (mass > 10^9 times solar mass) and forms a strikingly compact radio lobe. To a surface brightness contrast of at least 20 no radio lobe is detected on the side of the counter-jet, which is similar to the main jet in brightness upto the scale of tens of kpc. Thus, contrary to the nearly universal trend, the brightness asymmetry in this radio galaxy increases with distance from the nucleus. With several unusual properties, including a predominantly toroidal magnetic field, this Fanaroff-Riley type II (FR-II) mega-jet is an exceptionally useful laboratory for testing the role of magnetic field in jet stabilization and radio lobe formation.

  17. The Discovery of Diffuse Radio Polarization Structures in the NVSS

    CERN Document Server

    Rudnick, Lawrence

    2008-01-01

    We have developed a method for recovering polarization structures from the NRAO Very Large Array Sky Survey (NVSS) on larger angular scales than the nominal 15 arc minute survey limit. The technique depends on the existence of smaller scale fluctuations in polarization angle, to which the interferometer is sensitive, while the undetected total intensity of the structures can be arbitrarily large. We recover the large scale structure of the polarized Milky Way, as seen in single dish surveys, as well as a wide variety of smaller scale galactic and extragalactic features. We present a brief discussion of the uncertainties and limitations of the reprocessed NVSS polarization survey, a comparison of single-dish and NVSS results, and a sampling of the new polarization structures. We show a companion feature 1.8 Mpc outside of Abell cluster 3744, apparent Mpc-scale extensions to the tailed radio galaxy 3C31, a possible new giant galactic loop,and a new bright polarized patch in supernova remnant CTA1. We note that ...

  18. Cosmological measurements with forthcoming radio continuum surveys

    CSIR Research Space (South Africa)

    Raccanelli

    2012-08-01

    Full Text Available –819 (2012) doi:10.1111/j.1365-2966.2012.20634.x Cosmological measurements with forthcoming radio continuum surveys Alvise Raccanelli,1� Gong-Bo Zhao,1 David J. Bacon,1 Matt J. Jarvis,2,3 Will J. Percival,1 Ray P. Norris,4 Huub Ro¨ttgering,5 Filipe B. Abdalla... of Universe – radio continuum: galaxies. 1 IN T RO D U C T I O N Radio surveys for cosmology are entering a new phase with the construction of the Low Frequency Array (LOFAR) for radio �E-mail: alvise.raccanelli@port.ac.uk astronomy (Ro¨ttgering 2003...

  19. The effect of multiple scattering on the aspect sensitivity and polarization of radio auroral echoes

    Energy Technology Data Exchange (ETDEWEB)

    Donovan, E.F.; Moorcroft, D.R. (Western Ontario, University, London (Canada))

    1992-04-01

    A Monte Carlo model of radio wave scattering in the auroral electrojet has been developed to investigate multiple scattering of radio auroral echoes. Using this model, predictions of the aspect angle behavior of first-, second-, and third-order scattered power have been made. The results indicate that multiple scattering may be an important effect for VHF radars which observe the auroral E region at large magnetic aspect angles. The model shows that linearly polarized radio waves can become depolarized because of multiple scattering if the radio transmitter is horizontally polarized but not if the radio transmitter is vertically polarized. 52 refs.

  20. A real-time fast radio burst: polarization detection and multiwavelength follow-up

    CERN Document Server

    Petroff, E; Barr, E D; Barsdell, B R; Bhat, N D R; Bian, F; Burke-Spolaor, S; Caleb, M; Champion, D; Chandra, P; Da Costa, G; Delvaux, C; Flynn, C; Gehrels, N; Greiner, J; Jameson, A; Johnston, S; Kasliwal, M M; Keane, E F; Keller, S; Kocz, J; Kramer, M; Leloudas, G; Malesani, D; Mulchaey, J S; Ng, C; Ofek, E O; Perley, D A; Possenti, A; Schmidt, B P; Shen, Yue; Stappers, B; Tisserand, P; van Straten, W; Wolf, C

    2014-01-01

    Fast radio bursts (FRBs) are one of the most tantalizing mysteries of the radio sky; their progenitors and origins remain unknown and until now no rapid multiwavelength follow-up of an FRB has been possible. New instrumentation has decreased the time between observation and discovery from years to seconds, and enables polarimetry to be performed on FRBs for the first time. We have discovered an FRB (FRB 140514) in real-time on 14 May, 2014 at 17:14:11.06 UTC at the Parkes radio telescope and triggered follow-up at other wavelengths within hours of the event. FRB 140514 was found with a dispersion measure (DM) of 562.7(6) cm$^{-3}$ pc, giving an upper limit on source redshift of $z \\lesssim 0.5$. FRB 140514 was found to be 21$\\pm$7% (3-$\\sigma$) circularly polarized on the leading edge with a 1-$\\sigma$ upper limit on linear polarization $<10%$. We conclude that this polarization is intrinsic to the FRB. If there was any intrinsic linear polarization, as might be expected from coherent emission, then it may...

  1. On the Radio Polarization Signature of Efficient and Inefficient Particle Acceleration in Supernova Remnant SN 1006

    CERN Document Server

    Reynoso, Estela M; Moffett, David A

    2013-01-01

    We present a radio polarization study of SN 1006, based on combined VLA and ATCA observations at 20 cm that resulted in sensitive images with an angular resolution of 10 arcsec. The fractional polarization in the two bright radio and X-ray lobes of the SNR is measured to be 0.17, while in the southeastern sector, where the radio and non-thermal X-ray emission are much weaker, the polarization fraction reaches a value of 0.6 +- 0.2, close to the theoretical limit of 0.7. We interpret this result as evidence of a disordered, turbulent magnetic field in the lobes, where particle acceleration is believed to be efficient, and a highly ordered field in the southeast, where the acceleration efficiency has been shown to be very low. Utilizing the frequency coverage of our observations, an average rotation measure of ~12 rad/m2 is determined from the combined data set, which is then used to obtain the intrinsic direction of the magnetic field vectors. While the orientation of magnetic field vectors across the SNR shel...

  2. Flare processes evolution and polarization changes of fine structures of solar radio emission in the April 11, 2013 event

    CERN Document Server

    Chernov, Gennady; Tan, Baolin; Yan, Yihua; Tan, Chengming; Fu, Qijun; Karlicky, Marian; Fomichev, Valery

    2015-01-01

    The measurement of positions and sizes of radio sources in the observations of solar radio spectral fine structures in an M6.5 flare on April 11, 2013 were observed simultaneously by several radio instruments at four different observatories: Chinese Solar Broadband Radio Spectrometers at Huairou (SBRS/Huairou), Ondrejov Radio spectrograph in the Czech Republic (ORSC/Ondrejov), Badary Broadband Microwave spectropolarimeter (BMS/Irkutsk), and spectrograph/IZMIRAN (Moscow, Troitsk). The fine structures include microwave zebra patterns (ZP), fast pulsations, and fibers. They were observed during the flare brightening located at the tops of a loop arcade. The dynamics of the polarization was associated with the motion of the flare exciter, which was observed in EUV images at 171A and 131A (SDO/AIA). Combining magnetograms observed by the SDO Helioseismic and Magnetic Imager (HMI) with the homologous assumption of EUV flare brightening and ZP bursts, we deduced that the observed ZPs correspond to the ordinary radio...

  3. Radio Science Measurements with Suppressed Carrier

    Science.gov (United States)

    Asmar, Sami; Divsalar, Dariush; Oudrhiri, Kamal

    2013-01-01

    Radio Science started when it became apparent with early Solar missions that occultations by planetary atmospheres would affect the quality of radio communications. Since then the atmospheric properties and other aspects of planetary science, solar science, and fundamental physics were studied by scientists. Radio Science data was always extracted from a received pure residual carrier (without data modulation). For some missions, it is very desirable to obtain Radio Science data from a suppressed carrier modulation. In this paper we propose a method to extract Radio Science data when a coded suppressed carrier modulation is used in deep space communications. Type of modulation can be BPSK, QPSK, OQPSK, MPSK or even GMSK. However we concentrate mostly on BPSK modulation. The proposed method for suppressed carrier simply tries to wipe out data that acts as an interference for Radio Science measurements. In order to measure the estimation errors in amplitude and phase of the Radio Science data we use Cramer-Rao bound (CRB). The CRB for the suppressed carrier modulation with non-ideal data wiping is then compared with residual carrier modulation under the same noise condition. The method of derivation of CRB for non-ideal data wiping is an innovative method that presented here. Some numerical results are provided for coded system.

  4. Correlation between the Flux Density and Polarization for Flat Spectrum Radio Quasars

    Indian Academy of Sciences (India)

    Fei-Peng Pi; Yong-Xiang Wang; Jing Pan

    2011-03-01

    In this paper, using the preliminary database of the University of Michigan Radio Astronomy Observatory (UMRAO) at the radio frequencies, we calculated the weighted polarization at 8 GHz and investigated the correlation between the polarization and the flux density for 92 flat spectrum radio quasars (FSRQs). We found that the two observations are closely and positively correlated for FSRQs. This is perhaps from a relativistic beaming effect.

  5. Stokes tomography of radio pulsar magnetospheres. I. Linear polarization

    CERN Document Server

    Chung, C T Y

    2010-01-01

    Polarimetric studies of pulsar radio emission traditionally concentrate on how the Stokes vector (I, Q, U, V) varies with pulse longitude, with special emphasis on the position angle (PA) swing of the linearly polarized component. The interpretation of the PA swing in terms of the rotating vector model is limited by the assumption of an axisymmetric magnetic field and the degeneracy of the output with respect to the orientation and magnetic geometry of the pulsar; different combinations of the latter two properties can produce similar PA swings. This paper introduces Stokes phase portraits as a supplementary diagnostic tool with which the orientation and magnetic geometry can be inferred more accurately. The Stokes phase portraits feature unique patterns in the I-Q, I-U, and Q-U planes, whose shapes depend sensitively on the magnetic geometry, inclination angle, beam and polarization patterns, and emission altitude. We construct look-up tables of Stokes phase portraits and PA swings for pure and current-modif...

  6. Radio polarization and magnetic field structure in M 101

    CERN Document Server

    Berkhuijsen, E M; Beck, R; Han, J L

    2016-01-01

    We observed total and polarized radio continuum emission from the spiral galaxy M 101 at 6.2 cm and 11.1 cm wavelengths with the Effelsberg telescope. We use these data to study various emission components in M 101 and properties of the magnetic field. Separation of thermal and non-thermal emission shows that the thermal emission is closely correlated with the spiral arms, while the non-thermal emission is more smoothly distributed indicating diffusion of cosmic ray electrons away from their places of origin. The radial distribution of both emissions has a break near R=16 kpc, where it steepens to an exponential scale length of about 5 kpc, which is about 2.5 times smaller than at R<16 kpc. The distribution of the polarized emission has a broad maximum near R=12 kpc and beyond R=16 kpc also decreases with about 5 kpc scalelength. It seems that near R=16 kpc a major change in the structure of M 101 takes place, which also affects the distributions of the strength of the random and ordered magnetic field. Be...

  7. Evidence for the alignment of quasar radio polarizations with large quasar group axes

    Science.gov (United States)

    Pelgrims, V.; Hutsemékers, D.

    2016-05-01

    Recently, evidence has been presented for the polarization vectors from quasars to preferentially align with the axes of the large quasar groups (LQG) to which they belong. This report was based on observations made at optical wavelengths for two LQGs at redshift ~1.3. The correlation suggests that the spin axes of quasars preferentially align with their surrounding large-scale structure that is assumed to be traced by the LQGs. Here, we consider a large sample of LQGs built from the Sloan Digital Sky Survey DR7 quasar catalogue in the redshift range 1.0-1.8. For quasars embedded in this sample, we collected radio polarization measurements with the goal to study possible correlations between quasar polarization vectors and the major axis of their host LQGs. Assuming the radio polarization vector is perpendicular to the quasar spin axis, we found that the quasar spin axis is preferentially parallel to the LQG major axis inside LQGs that have at least 20 members. This result independently supports the observations at optical wavelengths. We additionally found that when the richness of an LQG decreases, the quasar spin axis becomes preferentially perpendicular to the LQG major axis and that no correlation is detected for quasar groups with fewer than 10 members.

  8. Dual-polarization and dual-mode orbital angular momentum radio vortex beam generated by using reflective metasurface

    Science.gov (United States)

    Yu, Shixing; Li, Long; Shi, Guangming

    2016-08-01

    A metasurface, which is composed of printed cross-dipole elements with different arm lengths, is designed, fabricated, and experimentally demonstrated to generate orbital angular momentum (OAM) vortex waves of dual polarizations and dual modes in the radio frequency domain simultaneously. The prototype of a practical metasurface is fabricated and measured to validate the results of theoretical analysis and design at 5.8 GHz. Numerical and experimental results verify that vortex waves with dual OAM modes and dual polarizations can be flexibly generated by using a reflective metasurface. The proposed method paves a way to generate diverse OAM vortex waves for radio frequency and microwave wireless communication applications.

  9. Radio occultation measurements of the lunar ionosphere.

    Science.gov (United States)

    Pluchino, S.; Schillirò, F.; Salerno, E.; Pupillo, G.; Maccaferri, G.; Cassaro, P.

    Radio occultation measurements by using interplanetary probes is a well known technique to obtain information on planetary atmospheres. To further understand the morphology of the lunar ionosphere we performed radio occultation experiments by using the radio sounding technique. This method mainly consists in the analisys of the effects produced on the radio wave transmitted from the spacecraft to the Earth when it crosses the atmosphere. The wave amplitude and phase undergo modifications that are correlated to the physical parameters - i.e. electron density - of the crossed medium. The first data set was obtained during the lunar occultations of the European probe SMART-1 shortly before impacting the lunar soil on September 3rd, 2006. During this experiment several radio occultation measurements of the signal transmitted by the spacecraft were performed in S and X band by using the 32 meters radiotelescopes (at Medicina and Noto) of the Istituto di Radioastronomia - Istituto Nazionale di Astrofisica. Further experiments were performed during lunar occultations of Saturn and Venus. On May 22nd and June 18th 2007 the Cassini spacecraft, orbiting Saturn, and the Venus Express spacecraft, orbiting Venus, respectively were occulted by the Moon. The variation of the Total Electron Content (TEC) measured by our instruments (˜ 1013 el/m2) on this occasion is in agreement with values of the electron number density acquired by in situ measuments of the US Apollo missions and the USSR Luna 19 and 22 probes.

  10. Circular polarization of radio emission from air showers probes atmospheric electric fields in thunderclouds.

    Science.gov (United States)

    Gia Trinh, Thi Ngoc; Scholten, Olaf; Buitink, Stijn; Corstanje, Arthur; Ebert, Ute; Enriquez, Emilio; Falcke, Heino; Horandel, Jörg R.; Nelles, Anna; Schellart, Pim; Rachen, Jorg; Rossetto, Laura; Rutjes, Casper; ter Veen, Sander; Thoudam, Satyendra

    2016-04-01

    When a high-energy cosmic-ray particle enters the upper layer of the atmosphere, it generates many secondary high-energy particles and forms a cosmic-ray-induced air shower. In the leading plasma of this shower electric currents are induced that emit electromagnetic radiation. These radio waves can be detected with LOw-Frequency ARray (LOFAR) radio telescope. Events have been collected under fair-weather conditions as well as under atmospheric conditions where thunderstorms occur. For the events under the fair weather conditions the emission process is well understood by present models. For the events measured under the thunderstorm conditions, we observe a large fraction of the circular polarization near the core of the shower which is not shown in the events under the fair-weather conditions. This can be explained by the change of direction of the atmospheric electric fields with altitude. Therefore, measuring the circular polarization of radio emission from cosmic ray extensive air showers during the thunderstorm conditions helps to have a better understanding about the structure of atmospheric electric fields in the thunderclouds.

  11. Magnetic field disorder and Faraday effects on the polarization of extragalactic radio sources

    CERN Document Server

    Lamee, Mehdi; Farnes, Jamie S; Carretti, Ettore; Gaensler, B M; Haverkorn, Marijke; Poppi, Sergio

    2016-01-01

    We present a polarization catalog of 533 extragalactic radio sources with 2.3 GHz total intensity above 420 mJy from the S-band Polarization All Sky Survey, S-PASS, with corresponding 1.4 GHz polarization information from the NRAO VLA Sky Survey, NVSS. We studied selection effects and found that fractional polarization, $\\pi$, of radio objects at both wavelengths depends on the spectral index, source magnetic field disorder, source size and depolarization. The relationship between depolarization, spectrum and size shows that depolarization occurs primarily in the source vicinity. The median $\\pi_{2.3}$ of resolved objects in NVSS is approximately two times larger than that of unresolved sources. Sources with little depolarization are $\\sim2$ times more polarized than both highly depolarized and re-polarized sources. This indicates that intrinsic magnetic field disorder is the dominant mechanism responsible for the observed low fractional polarization of radio sources at high frequencies. We predict that numbe...

  12. Mapping the Polarization of the Radio-Loud lya Nebula B3 J2330+3927

    Science.gov (United States)

    You, Chang; Zabludoff, Ann; Smith, Paul; Yang, Yujin; Kim, Eunchong; Jannuzi, Buell; Prescott, Moire K. M.; Matsuda, Yuichi; Lee, Myung Gyoon

    2017-01-01

    Lyα nebulae, or “Lyα blobs,” are extended (up to ∼100 kpc), bright (LLyα ≳ 1043 erg s‑1) clouds of Lyα emitting gas that tend to lie in overdense regions at z ∼ 2–5. The origin of the Lyα emission remains unknown, but recent theoretical work suggests that measuring the polarization might discriminate among powering mechanisms. Here we present the first narrowband imaging polarimetry of a radio-loud Lyα nebula, B3 J2330+3927, at z = 3.09, with an embedded active galactic nucleus (AGN). The AGN lies near the blob’s Lyα emission peak, and its radio lobes align roughly with the blob’s major axis. With the SPOL polarimeter on the 6.5 m MMT telescope, we map the total (Lyα + continuum) polarization in a grid of circular apertures of a radius of 0.″6 (4.4 kpc), detecting a significant (>2σ) polarization fraction P% in nine apertures and achieving strong upper limits (as low as 2%) elsewhere. P% increases from <2% at ∼5 kpc from the blob center to 17% at ∼15–25 kpc. The detections are distributed asymmetrically, roughly along the nebula’s major axis. The polarization angles θ are mostly perpendicular to this axis. Comparing the Lyα flux to that of the continuum and conservatively assuming that the continuum is highly polarized (20%–100%) and aligned with the total polarization, we place lower limits on the polarization of the Lyα emission P%,Lyα ranging from no significant polarization at ∼5 kpc from the blob center to 3%–17% at 10–25 kpc. Like the total polarization, the Lyα polarization detections occur more often along the blob’s major axis. The observations reported here were obtained at the MMT Observatory, a joint facility of the University of Arizona and the Smithsonian Institution.

  13. Future Nanosatellite Constellation for Radio Occultation Measurements

    Science.gov (United States)

    Fallet, C.; Mahfouf, J. F.; Hauchechrne, A.; Mathieu, R.; Martin, T.; Capet, N.; Mandea, M.

    2016-08-01

    The future nanosatellite constellation for radio occultation measurements aims to provide 10000 occultations per day (horizon 2020). The radio occultation technique based on the refraction of an electromagnetic signal between a GNSS satellite (Global Navigation Satellite System) and a receiver satellite located o a low orbit provides a way to observe the Earth's atmosphere, especially its temperature, pressure and water vapor, but also the ionosphere. This technique is now considered a mature concept, the benefits clearly recognized by the communities of weather prediction, climatology and space weather. Activities are underway at CNES to define a low cost system and instrumental concept to satisfy the specifications of the different communities.

  14. Polarizing Michelson interferometer for measuring thermospheric winds

    Energy Technology Data Exchange (ETDEWEB)

    Bird, J.C.

    1991-01-01

    The Polarizing Atmospheric Michelson Interferometer, PAMI, a new version of the Wide Angle Michelson Interferometer, is used to measure winds in the termosphere. In the polarizing instrument, the optical path difference is changed simply by rotating a polarizing filter external to the interferometer. This allows a very simple scanning mechanism. PAMI is similar to other instruments such as WAMDII that measure thermospheric winds and temperatures, retaining the benefits of high light throughput, while offering advantages including lower cost, simplicity, and portability. The instrument is highly sensitive and thus is designed to be used for field measurements at locations far from city lights. Results are shown from the AIDA observation campaign in Puerto Rico where coordinated observations were made by PAMI along with other optical and radio measurements during April and May 1989. Intensities of the green line layer at 95 km were compared to those observed by several other instruments. For example, MORTI (Mesopause Oxygen Rotational Temperature Imager), a colocated instrument which was looking at the 94 km 867.6 nm molecular oxygen emission. MORTI and PAMI emission rates were found to show the same trends. On the brightest night recorded during April, the zenith emission rate reached over 400 Rayleighs; emission enhancements were sometimes related to auroral events. During the observing period of April 4 to April 11, 1989, most of the observations of the 94 km airglow were after midnight where the winds were found to be generally towards the north east at about 50 to 100 m/s. During auroral activity this wind vector always turned counterclockwise, towards the west. During the nights of May 2 and May 6 these wind vectors follow a wave-like variation in magnitude and direction. It is concluded that auroral activity changes the global circulation in a way that sometimes transports increased amounts of oxygen atoms over Arecibo.

  15. Radio polarization and magnetic field structure in M 101

    Science.gov (United States)

    Berkhuijsen, E. M.; Urbanik, M.; Beck, R.; Han, J. L.

    2016-04-01

    We observed total and polarized radio continuum emission from the spiral galaxy M 101 at λλ 6.2 cm and 11.1 cm with the Effelsberg telescope. The angular resolutions are 2.´ 5 (=5.4 kpc) and 4.´ 4 (=9.5 kpc), respectively. We use these data to study various emission components in M 101 and properties of the magnetic field. Separation of thermal and non-thermal emission shows that the thermal emission is closely correlated with the spiral arms, while the non-thermal emission is more smoothly distributed indicating diffusion of cosmic ray electrons away from their places of origin. The radial distribution of both emissions has a break near R = 16 kpc (=7.´ 4), where it steepens to an exponential scale length of L ≃ 5 kpc, which is about 2.5 times smaller than at Rlength of both fields is about 20 kpc, which implies that they decrease to about 0.3 μG at R = 70 kpc, which is the largest optical extent. The equipartition strength of the total field ranges from nearly 10 μG at R< 2 kpc to 4 μG at R = 22-24 kpc. As the random field dominates in M 101 (Bran/Bord ≃ 2.4), wavelength-independent polarization is the main polarization mechanism. We show that energetic events causing H i shells of mean diameter < 625 pc could partly be responsible for this. At radii < 24 kpc, the random magnetic field depends on the star formation rate/area, ΣSFR, with a power-law exponent of b = 0.28 ± 0.02. The ordered magnetic field is generally aligned with the spiral arms with pitch angles that are about 8° larger than those of H i filaments. Based on observations with the 100 m telescope of the MPIfR at Effelsberg.FITS files of the images are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/588/A114

  16. Experimental Array for Generating Dual Circularly-Polarized Dual-Mode OAM Radio Beams

    Science.gov (United States)

    Bai, Xu-Dong; Liang, Xian-Ling; Sun, Yun-Tao; Hu, Peng-Cheng; Yao, Yu; Wang, Kun; Geng, Jun-Ping; Jin, Rong-Hong

    2017-01-01

    Recently, vortex beam carrying orbital angular momentum (OAM) for radio communications has attracted much attention for its potential of transmitting multiple signals simultaneously at the same frequency, which can be used to increase the channel capacity. However, most of the methods for getting multi-mode OAM radio beams are of complicated structure and very high cost. This paper provides an effective solution of generating dual circularly-polarized (CP) dual-mode OAM beams. The antenna consists of four dual-CP elements which are sequentially rotated 90 degrees in the clockwise direction. Different from all previous published research relating to OAM generation by phased arrays, the four elements are fed with the same phase for both left-hand circular polarization (LHCP) and right-hand circular polarization (RHCP). The dual-mode operation for OAM is achieved through the opposite phase differences generated for LHCP and RHCP, when the dual-CP elements are sequentially rotated in the clockwise direction. The measured results coincide well with the simulated ones, which verified the effectiveness of the proposed design.

  17. Radio polarization observations of large supernova remnants at 6cm

    CERN Document Server

    Han, J L; Sun, X H; Reich, W; Xiao, L; Reich, P; Xu, J W; Shi, W B; Fuerst, E; Wielebinski, R

    2013-01-01

    We have observed 79 supernova remnants (SNRs) with the Urumqi 25m telescope at 6cm during the Sino-German 6cm polarization survey of the Galactic plane. We measured flux densities of SNRs at 6cm, some of which are the first measurements or the data at highest frequencies, so that we can determine or improve spectra of SNRs. Our observations have ruled out the suggested spectral breaks or spectral flattening of a few SNRs, and confirmed the spectral break of S147. Combined our 6cm maps with 11cm and 21cm maps from the Effelsberg 100m telescope, we calculated the spectral index maps of several large SNRs. For many remnants, we obtained for the first time polarization images, which show the intrinsic magnetic field structures at 6 cm. We disapproved three "remnants", OA184, G192.8-1.1 and G16.8-1.1, which show a thermal spectrum and no polarization. We have discovered two large supernova remnant, G178.2-4.2 and G25.1-2.3, from the 6cm survey maps.

  18. CHANG-ES - VIII. Uncovering hidden AGN activity in radio polarization

    Science.gov (United States)

    Irwin, Judith A.; Schmidt, Philip; Damas-Segovia, A.; Beck, Rainer; English, Jayanne; Heald, George; Henriksen, Richard N.; Krause, Marita; Li, Jiang-Tao; Rand, Richard J.; Wang, Q. Daniel; Wiegert, Theresa; Kamieneski, Patrick; Paré, Dylan; Sullivan, Kendall

    2017-01-01

    We report on C-band (5-7 GHz) observations of the galaxy, NGC 2992, from the Continuum Halos in Nearby Galaxies - an EVLA Survey (CHANG-ES) sample. This galaxy displays an embedded nuclear double-lobed radio morphology within its spiral disc, as revealed in linearly polarized emission but not in total intensity emission. The radio lobes are kpc-sized, similar to what has been observed in the past for other Seyfert galaxies, and show ordered magnetic fields. NGC 2992 has shown previous evidence for AGN-related activity, but not the linearly polarized radio features that we present here. We draw attention to this galaxy as the first clear example (and prototype) of bipolar radio outflow that is revealed in linearly polarized emission only. Such polarization observations, which are unobscured by dust, provide a new tool for uncovering hidden weak active galactic nucleus (AGN) activity which may otherwise be masked by brighter unpolarized emission within which it is embedded. The radio lobes observed in NGC 2992 are interacting with the surrounding interstellar medium (ISM) and offer new opportunities to investigate the interactions between nuclear outflows and the ISM in nearby galaxies. We also compare the radio emission with a new CHANDRA X-ray image of this galaxy. A new CHANG-ES image of NGC 3079 is also briefly shown as another example as to how much more obvious radio lobes appear in linear polarization as opposed to total intensity.

  19. Rapid radio polarization variability in the quasar 0917 + 624

    Energy Technology Data Exchange (ETDEWEB)

    Quirrenbach, A.; Witzel, A.; Qian, S.J.; Krichbaum, T.; Hummel, C.A.; Alberdi, A. (Max-Planck-Institut fuer Radioastronomie, Bonn 1 (DE))

    1989-12-01

    We have made measurements of the total flux density and the polarization of the quasar 0917+624 with a sampling of {approx} 1 hour using the 100 m telescope of the Max-Planck-Institut fuer Radioastronomie (MPIfR) at 6 and 11 cm wavelength. The total flux density showed variations with an amplitude of {approx} 25% and a typical time scale of {approx} 1 day at both wavelengths. The polarized flux density P showed even more dramatic variations with an amplitude of a factor {approx} 3, correlated with the variability of the total flux density S, P being high whenever S was low and vice versa. At 6 cm wavelength a swing of the polarization position angle {chi} of 180{sup 0} wasobserved at a time when the total flux density showed a maximum. These findings make any extrinsic explanations of the effect (e.g. scattering in the interstellar medium) very unlikely. We discuss a model which gives an explanation of the observed variability in terms of shocks propagating in a magnetized jet.

  20. SNR radio spectral index distribution and its correlation with polarization: a case study of Lupus Loop

    CERN Document Server

    Jovanović, V Borka; Borka, D

    2016-01-01

    We use radio-continuum all-sky surveys at 1420 and 408 MHz with the aim to investigate properties of the Galactic radio source Lupus Loop. The survey data at 1435 MHz, with the linear polarization of the southern sky, is also used. We calculate properties of this supernova remnant: the brightness temperature, surface brightness and radio spectral index. For determining borders and calculation of its properties, we use the method we have developed. The non-thermal nature of its radiation is confirmed. The distribution of spectral index over its area is also given. A significant correlation between the radio spectral index distribution and the corresponding polarized intensity distribution inside the loop borders is found, indicating that the polarization maps could provide us information about the distribution of interstellar medium, and thus could represent one additional way to search for new Galactic loops.

  1. SNR radio spectral index distribution and its correlation with polarization. a case study: the Lupus Loop

    Science.gov (United States)

    Borka Jovanović, V.; Jovanović, P.; Borka, D.

    2017-04-01

    We use radio-continuum all-sky surveys at 1420 and 408 MHz with the aim to investigate properties of the Galactic radio source Lupus Loop. The survey data at 1435 MHz, with the linear polarization of the southern sky, are also used. We calculate properties of this supernova remnant: the brightness temperature, surface brightness and radio spectral index. To determine its borders and to calculate its properties, we use the method we have developed. The non-thermal nature of its radiation is confirmed. The distribution of spectral index over its area is also given. A significant correlation between the radio spectral index distribution and the corresponding polarized intensity distribution inside the loop borders is found, indicating that the polarization maps could provide us information about the distribution of the interstellar medium, and thus could represent one additional way to search for new Galactic loops.

  2. Radio emission from RS CVn binaries. II - Polarization and spectral properties

    Science.gov (United States)

    Mutel, R. L.; Morris, D. H.; Doiron, D. J.; Lestrade, J. F.

    1987-05-01

    Multi-epoch radio observations of circular polarization and spectral characteristics of several close, late-type stellar binaries (mainly of the RS CVn class) are reported. The median luminosity of four well-studied systems ranged from 16.2 ≤ log(LR) ≤ 17.1 erg s-1Hz-1. For individual systems, the fractional circular polarization decreases with increasing luminosity, particularly at frequencies f ≥ 5 GHz. Eclipsing binaries have significantly lower average circular polarization compared with non-eclipsing systems. Helicity reversal is almost always observed between 1.4 and 4.9 GHz for systems with high orbital inclination. These spectral and polarization characteristics, combined with direct measurements of the brightness temperature using previously published VLBI observations, strongly support a model of inhomogeneous gyrosynchrotron emission arising from electrons with power law energy spectra interacting with inhomogeneous magnetic fields. The source emission region is probably cospatial with the large coronal loops deduced from X-ray observations.

  3. Finding a faint polarized signal in wide-band radio data

    CERN Document Server

    Schnitzeler, D H F M

    2016-01-01

    We develop two algorithms, based on maximum likelihood (ML) inference, for estimating the parameters of polarized radio sources which emit at a single rotation measure (RM), e.g., pulsars. These algorithms incorporate the flux density spectrum of the source, either a power law or a scaled version of the Stokes I spectrum, and a variation in sensitivity across the observing band. We quantify the detection significance and measurement uncertainties in the fitted parameters, and we derive weighted versions of the RM synthesis algorithm which, under certain conditions, maximize the likelihood. We use Monte Carlo simulations to compare injected and recovered source parameters for a range of signal-to-noise ratios, investigate the quality of standard methods for estimating measurement uncertainties, and search for statistical biases. These simulations consider one frequency band each for the Australia Telescope Compact Array (ATCA), the Square Kilometre Array (SKA), and the Low Frequency Array (LOFAR). We find that...

  4. Measurement of polarization with the Degree Angular Scale Interferometer.

    Science.gov (United States)

    Leitch, E M; Kovac, J M; Pryke, C; Carlstrom, J E; Halverson, N W; Holzapfel, W L; Dragovan, M; Reddall, B; Sandberg, E S

    Measurements of the cosmic microwave background (CMB) radiation can reveal with remarkable precision the conditions of the Universe when it was approximately 400,000 years old. The three most fundamental properties of the CMB are its frequency spectrum (which determines the temperature), and the fluctuations in both the temperature and polarization across a range of angular scales. The frequency spectrum has been well determined, and considerable progress has been made in measuring the power spectrum of the temperature fluctuations. But despite many efforts to measure the polarization, detection of this property of the CMB has hitherto been beyond the reach of even the most sensitive observations. Here we describe the Degree Angular Scale Interferometer (DASI), an array of radio telescopes, which for the past two years has conducted polarization-sensitive observations of the CMB from the Amundsen-Scott South Pole research station.

  5. Observational Characteristics of Radio Emission Related to Multi-polar Magnetic Configuration

    Institute of Scientific and Technical Information of China (English)

    Min Wang; Rui-Xiang Xie; Chun Xu; Shuo-Biao Shi; Yi-Hua Yan

    2005-01-01

    We present a large complex radio burst and its associated fast time structures observed on 2001 April 10 in the frequency range of 0.65-7.6 GHz. The NoRH radio image observation shows very complex radio source structures which include preexisting, newly emerging, submerging/cancelling polarities and a biposuggests that the radio burst is generated from a very complicated loop structure.According to the spectral and image observations, we assume that the beginning connection structure. A composite of radio continuum and fast time structures is contained in this flare. The various fast radio emission phenomena include normal and reverse drifting type Ⅲ bursts, and slowly drifting and no-drift structures.ture, which is an important source of the various types of fast time structures.The two-loop reconnection model can lead simultaneously to electron acceleration and corona heating. We have also analyzed the behaviors of coronal magnetic polarities and the emission processes of different types radio emission qualitatively.Interactions of a bipolar or multi-polar loop are consistent with our observational results. Our observations favor the magnetic reconnection configurations of the lar).

  6. Cosmological measurements with forthcoming radio continuum surveys

    CSIR Research Space (South Africa)

    Raccanelli, A

    2012-08-01

    Full Text Available -correlation between radio sources and cosmic microwave background (CMB) maps (the integrated Sachs–Wolfe effect), the crosscorrelation of radio sources with foreground objects resulting from cosmic magnification, and a joint analysis together with the CMB power...

  7. Application of the elliptically polarized radio frequency fields in spin-3/2 nuclear quadrupole resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Sklyar, Anna; Ostafin, Michal; Nogaj, Boleslaw [Dept. of Physics, Adam Mickiewicz Univ., Poznan (Poland); Sinyavsky, Nikolay [Baltic State Academy, Kaliningrad (Russian Federation)

    2009-09-15

    A possibility to excite the spin-3/2 quadrupolar nuclei in sites with a non-zero asymmetry parameter of the electric field gradient (EFG) tensor by means of an elliptically polarized radio frequency (RF) magnetic fields is discussed. Closed analytical formulas for the intensities of nuclear quadrupole resonance (NQR) nutation spectra and nutation, frequencies of powder samples were obtained. Characteristic singularities in the nutation spectra were determined which allow the measurement of the asymmetry parameter {eta}. It was found that in the general case of {eta} {ne} 0 the excitation of the nuclear spins in +m and -m states by using the circularly polarized RF fields is not fully selective. (orig.)

  8. Hubble Space Telescope NICMOS Polarization Measurements of OMC-1

    Science.gov (United States)

    Simpson, Janet P.; Colgan, Sean W. J.; Erickson, Edwin F.; Burton, Michael G.; Schultz, A. S. B.

    2006-01-01

    We present 2 micrometer polarization measurements of positions in the BN region of the Orion Molecular Cloud (OMC-1) made with NICMOS Camera 2 (0.2" resolution) on Hubble Space Telescope. Our goals are to seek the sources of heating for IRc2, 3, 4, and 7, identify possible young stellar objects (YSOs), and characterize the grain alignment in the dust clouds along the lines-of-sight to the stars. Our results are as follows: BN is approximately 29% polarized by dichroic absorption and appears to be the illuminating source for most of the nebulosity to its north and up to approximately 5" to its south. Although the stars are probably all polarized by dichroic absorption, there are a number of compact, but non-point-source, objects that could be polarized by a combination of both dichroic absorption and local scattering of star light. We identify several candidate YSOs, including an approximately edge-on bipolar YSO 8.7" east of BN, and a deeply-embedded IRc7, all of which are obviously self-luminous at mid-infrared wavelengths and may be YSOs. None of these is a reflection nebula illuminated by a star located near radio source I, as was previously suggested. Other IRc sources are clearly reflection nebulae: IRc3 appears to be illuminated by IRc2-B or a combination of the IRc2 sources, and IRc4 and IRc5 appear to be illuminated by an unseen star in the vicinity of radio source I, or by Star n or IRc2-A. Trends in the magnetic field direction are inferred from the polarization of the 26 stars that are bright enough to be seen as NICMOS point sources. Their polarization ranges from N less than or equal to 1% (all stars with this low polarization are optically visible) to greater than 40%. The most polarized star has a polarization position angle different from its neighbors by approximately 40 degrees, but in agreement with the grain alignment inferred from millimeter polarization measurements of the cold dust cloud in the southern part of OMC-1. The polarization

  9. Polarization of radio cores as a test of the unified schemes

    CERN Document Server

    Saikia, D J

    1998-01-01

    In the unified schemes for extragalactic radio sources, the quasars and BL Lac objects are intrinsically similar to the Fanaroff-Riley class II and I radio galaxies respectively, but appear to be different because they are viewed at different angles to the line-of-sight. The quasars and BL Lac objects are observed at small viewing angles while the radio galaxies lie close to the plane of the sky. In such schemes, the quasar or BL Lac nucleus is hidden from our view by a putative torus when the source is inclined at a large angle to the line-of-sight and appears as a radio galaxy. Such a scenario should also affect the observed polarization properties of the cores, with the cores in the radio galaxies and weak-cored quasars being less polarized than the core-dominated quasars and BL Lacs due to Faraday depolarization by the magnetoionic medium in the obscuring torus or disk. In this paper, we report that the core polarization of radio galaxies and weak-cored quasars is indeed much smaller than for the core-dom...

  10. CHANG-ES VIII: Uncovering Hidden AGN Activity in Radio Polarization

    CERN Document Server

    Irwin, Judith A; Damas-Segovia, A; Beck, Rainer; English, Jayanne; Heald, George; Henriksen, Richard N; Krause, Marita; Li, Jiang-Tao; Rand, Richard J; Wang, Q Daniel; Wiegert, Theresa; Kamieneski, Patrick; Paré, Dylan; Sullivan, Kendall

    2016-01-01

    We report on C-band (5 - 7 GHz) observations of the galaxy, NGC~2992, from the CHANG-ES sample. This galaxy displays an embedded nuclear double-lobed radio morphology within its spiral disk, as revealed in linearly polarized emission but {\\it not} in total intensity emission. The radio lobes are kpc-sized, similar to what has been observed in the past for other Seyfert galaxies, and show ordered magnetic fields. NGC~2992 has shown previous evidence for AGN-related activity, but not the linearly polarized radio features that we present here. We draw attention to this galaxy as the first clear example (and prototype) of bipolar radio outflow that is revealed in linearly polarized emission only. Such polarization observations, which are unobscured by dust, provide a new tool for uncovering hidden weak AGN activity which may otherwise be masked by brighter unpolarized emission within which it is embedded. The radio lobes observed in NGC~2992 are interacting with the surrounding interstellar medium and offer new o...

  11. Interpretation of the Global Anisotropy in the Radio Polarizations of Cosmologically Distant Sources

    Indian Academy of Sciences (India)

    Pankaj Jain; S. Sarala

    2006-12-01

    We present a detailed statistical study of the observed anisotropy in radio polarizations from distant extragalactic objects. This anisotropy was earlier found by Birch (1982) and reconfirmed by Jain and Ralston (1999) in a larger data set. A very strong signal was seen after imposing the cut $|RM-\\overline{RM}| \\gt 6$ rad/m2, where RM is the rotation measure and $\\overline{RM}$ its mean value. In this paper, we show that there are several indications that this anisotropy cannot be attributed to bias in the data. We also find that a generalized statistic shows a very strong signal in the entire data without imposing the RM dependent cut. Finally we argue that an anisotropic background pseudoscalar field can explain the observations.

  12. Maximizing the utility of radio spectrum: Broadband spectrum measurements and occupancy model for use by cognitive radio

    Science.gov (United States)

    Petrin, Allen J.

    Radio spectrum is a vital national asset; proper management of this finite resource is essential to the operation and development of telecommunications, radio-navigation, radio astronomy, and passive remote sensing services. To maximize the utility of the radio spectrum, knowledge of its current usage is beneficial. As a result, several spectrum studies have been conducted in urban Atlanta, suburban Atlanta, and rural North Carolina. These studies improve upon past spectrum studies by resolving spectrum usage by nearly all its possible parameters: frequency, time, polarization, azimuth, and location type. The continuous frequency range from 400MHz to 7.2 GHz was measured with a custom-designed system. More than 8 billion spectrum measurements were taken over several months of observation. A multi-parameter spectrum usage detection method was developed and analyzed with data from the spectrum studies. This method was designed to exploit all the characteristics of spectral information that was available from the spectrum studies. Analysis of the spectrum studies showed significant levels of underuse. The level of spectrum usage in time and azimuthal space was determined to be only 6.5 % for the urban Atlanta, 5.3 % for suburban Atlanta, and 0.8 % for the rural North Carolina spectrum studies. Most of the frequencies measured never experienced usage. Interference was detected in several protected radio astronomy and sensitive radio navigation bands. A cognitive radio network architecture to share spectrum with fixed microwave systems was developed. The architecture uses a broker-based sharing method to control spectrum access and investigate interference issues.

  13. Characterization of dual-polarization LTE radio over a free-space optical turbulence channel.

    Science.gov (United States)

    Bohata, J; Zvanovec, S; Korinek, T; Mansour Abadi, M; Ghassemlooy, Z

    2015-08-10

    A dual polarization (DP) radio over a free-space optical (FSO) communication link using a long-term evolution (LTE) radio signal is proposed and analyzed under different turbulence channel conditions. Radio signal transmission over the DP FSO channel is experimentally verified by means of error vector magnitude (EVM) statistics. We demonstrate that such a system, employing a 64 quadrature amplitude modulation at the frequency bands of 800 MHz and 2.6 GHz, evinces reliability with LTE signal over the FSO channel is a potential solution for last-mile access or backbone networks, when using multiple-input multiple-output based DP signals.

  14. Measuring interstellar magnetic fields by radio synchrotron emission

    CERN Document Server

    Beck, Rainer

    2009-01-01

    Radio synchrotron emission, its polarization and its Faraday rotation are powerful tools to study the strength and structure of interstellar magnetic fields. The total intensity traces the strength and distribution of total magnetic fields. Total fields in gas-rich spiral arms and bars of nearby galaxies have strengths of 20-30 $\\mu$Gauss, due to the amplification of turbulent fields, and are dynamically important. In the Milky Way, the total field strength is about 6 $\\mu$G near the Sun and several 100 $\\mu$G in filaments near the Galactic Center. -- The polarized intensity measures ordered fields with a preferred orientation, which can be regular or anisotropic fields. Ordered fields with spiral structure exist in grand-design, barred, flocculent and even in irregular galaxies. The strongest ordered fields are found in interarm regions, sometimes forming "magnetic spiral arms" between the optical arms. Halo fields are X-shaped, probably due to outflows. -- The Faraday rotation of the polarization vectors tr...

  15. Faraday Rotation from Magnesium II Absorbers towards Polarized Background Radio Sources

    CERN Document Server

    Farnes, J S; Corrigan, M E; Gaensler, B M

    2014-01-01

    Strong magnesium II (MgII) absorption lines in quasar spectra typically serve as a proxy for an intervening galaxy along the line of sight. Previous studies have found a correlation between the number of these MgII absorbers and the rotation measure (RM) at $\\approx5$ GHz. We cross-match a sample of 35,752 optically-identified non-intrinsic MgII absorption systems with 25,649 polarized background radio sources for which we have measurements of both the spectral index and RM at 1.4 GHz. We use the spectral index to split the resulting sample of 599 sources into flat-spectrum and steep-spectrum subsamples. We find that our flat-spectrum sample shows significant ($\\sim3.5\\sigma$) evidence for a correlation between MgII absorption and RM at 1.4 GHz, while our steep-spectrum sample shows no such correlation. We argue that such an effect cannot be explained by either luminosity or other observational effects, by evolution in another confounding variable, by wavelength-dependent polarization structure in an active g...

  16. Spectropolarimetry with the Allen Telescope Array: Faraday Rotation toward Bright Polarized Radio Galaxies

    CERN Document Server

    Law, C J; Bower, G C; Backer, D C; Bauermeister, A; Croft, S; Forster, R; Gutierrez-Kraybill, C; Harvey-Smith, L; Heiles, C; Hull, C; Keating, G; MacMahon, D; Whysong, D; Williams, P K G; Wright, M

    2010-01-01

    We have observed 37 bright, polarized radio sources with the Allen Telescope Array (ATA) to present a novel analysis of their Faraday rotation properties. Each source was observed during the commissioning phase with 2 to 4 100-MHz bands at frequencies ranging from 1 to 2 GHz. These observations demonstrate how the continuous frequency coverage of the ATA's log-periodic receiver can be applied to the study of Faraday rotation measures (RMs). We use RM synthesis to show that wide-bandwidth data can find multiple RM components toward a single source. Roughly a quarter of the sources studied have extra RM components with high confidence (brighter than ~40 mJy), when observing with a RM resolution of roughly 100 rad/m2. These extra components contribute 10%-70% of the total polarized flux. This is the first time multiple RM components have been identified in a large sample of point sources. For our observing configuration, these extra RM components bias the measurement of the peak RM by 10-15 rad/m2 ; more general...

  17. Magnetic Field Disorder and Faraday Effects on the Polarization of Extragalactic Radio Sources

    Science.gov (United States)

    Lamee, Mehdi; Rudnick, Lawrence; Farnes, Jamie S.; Carretti, Ettore; Gaensler, B. M.; Haverkorn, Marijke; Poppi, Sergio

    2016-09-01

    We present a polarization catalog of 533 extragalactic radio sources that have a 2.3 GHz total intensity above 420 mJy from the S-band Polarization All Sky Survey, S-PASS, with corresponding 1.4 GHz polarization information from the NRAO VLA Sky Survey, NVSS. We studied the selection effects and found that fractional polarization, π, of radio objects at both wavelengths depends on the spectral index, the source magnetic field disorder, the source size, and depolarization. The relationship between depolarization, spectrum, and size shows that depolarization occurs primarily in the source vicinity. The median {π }2.3 of resolved objects in NVSS is approximately two times larger than that of unresolved sources. Sources with little depolarization are ∼2 times more polarized than both highly depolarized and re-polarized sources. This indicates that intrinsic magnetic field disorder is the dominant mechanism responsible for the observed low fractional polarization of radio sources at high frequencies. We predict that number counts from polarization surveys will be similar at 1.4 GHz and at 2.3 GHz, for fixed sensitivity, although ∼10% of all sources may currently be missing because of strong depolarization. Objects with {π }1.4≈ {π }2.3≥slant 4 % typically have simple Faraday structures, so they are most useful for background samples. Almost half of flat-spectrum (α ≥slant -0.5) and ∼25% of steep-spectrum objects are re-polarized. Steep-spectrum, depolarized sources show a weak negative correlation of depolarization with redshift in the range 0 < z < 2.3. Previous non-detections of redshift evolution are likely due the inclusion of re-polarized sources as well.

  18. The Growth, Polarization, and Motion of the Radio Afterglow from the Giant Flare from SGR 1806-20

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, G

    2005-04-20

    The extraordinary giant flare (GF) of 2004 December 27 from the soft gamma repeater (SGR) 1806-20 was followed by a bright radio afterglow. We present an analysis of VLA observations of this radio afterglow from SGR1806-20, consisting of previously reported 8.5 GHz data covering days 7 to 20 after the GF, plus new observations at 8.5 and 22 GHz from day 24 to 81. For a symmetric outflow, we find a deceleration in the expansion, from {approx}4.5 mas/day to <2.5 mas/day. The time of deceleration is roughly coincident with the rebrightening in the radio light curve, as expected to result when the ejecta from the GF sweeps up enough of the external medium, and transitions from a coasting phase to the Sedov-Taylor regime. The radio afterglow is elongated and maintains a 2:1 axis ratio with an average position angle of -40{sup o} (north through east), oriented perpendicular to the average intrinsic linear polarization angle. We also report on the discovery of motion in the flux centroid of the afterglow, at an average velocity of 0.26 {+-} 0.03 c (assuming a distance of 15 kpc) at a position angle of -45{sup o}. This motion, in combination with the growth and polarization measurements, suggests an initially asymmetric outflow, mainly from one side of the magnetar.

  19. A STUDY OF RADIO POLARIZATION IN PROTOSTELLAR JETS

    Energy Technology Data Exchange (ETDEWEB)

    Cécere, Mariana [Instituto de Astronomía Teórica y Experimental, Universidad Nacional de Córdoba, X5000BGR, Córdoba (Argentina); Velázquez, Pablo F.; De Colle, Fabio; Esquivel, Alejandro [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Apdo. Postal 70-543, CP: 04510, D.F., México (Mexico); Araudo, Anabella T. [University of Oxford, Astrophysics, Keble Road, Oxford OX1 3RH (United Kingdom); Carrasco-González, Carlos; Rodríguez, Luis F. [Instituto de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, Apdo. Postal 3-72, 58090, Morelia, Michoacán, México (Mexico)

    2016-01-10

    Synchrotron radiation is commonly observed in connection with shocks of different velocities, ranging from relativistic shocks associated with active galactic nuclei, gamma-ray bursts, or microquasars, to weakly or non-relativistic flows such as those observed in supernova remnants. Recent observations of synchrotron emission in protostellar jets are important not only because they extend the range over which the acceleration process works, but also because they allow us to determine the jet and/or interstellar magnetic field structure, thus giving insights into the jet ejection and collimation mechanisms. In this paper, we compute for the first time polarized (synchrotron) and non-polarized (thermal X-ray) synthetic emission maps from axisymmetrical simulations of magnetized protostellar jets. We consider models with different jet velocities and variability, as well as a toroidal or helical magnetic field. Our simulations show that variable, low-density jets with velocities of ∼1000 km s{sup −1} and ∼10 times lighter than the environment can produce internal knots with significant synchrotron emission and thermal X-rays in the shocked region of the leading bow shock moving in a dense medium. While models with a purely toroidal magnetic field show a very large degree of polarization, models with a helical magnetic field show lower values and a decrease of the degree of polarization, in agreement with observations of protostellar jets.

  20. Physical Conditions and Variability Processes in AGN Jets through Multi-Frequency Linear and Circular Radio Polarization Monitoring

    Science.gov (United States)

    Myserlis, Ioannis; Angelakis, Emmanouil; Kraus, Alex; Fuhrmann, Lars; Karamanavis, Vassilis; Zensus, J.

    2016-11-01

    Radio polarimetry is an invaluable tool to investigate the physical conditions and variability processes in active galactic nuclei (AGN) jets. However, detecting their linear and circular polarization properties is a challenging endeavor due to their low levels and possible depolarization effects. We have developed an end-to-end data analysis methodology to recover the polarization properties of unresolved sources with high accuracy. It has been applied to recover the linear and circular polarization of 87 AGNs measured by the F-GAMMA program from July 2010 to January 2015 with a mean cadence of 1.3 months. Their linear polarization was recovered at four frequencies between 2.64 and 10.45 GHz and the circular polarization at 4.85 and 8.35 GHz. The physical conditions required to reproduce the observed polarization properties and the processes which induce their variability were investigated with a full-Stokes radiative transfer code which emulates the synchrotron emission of modeled jets. The model was used to investigate the conditions needed to reproduce the observed polarization behavior for the blazar 3C 454.3, assuming that the observed variability is attributed to evolving internal shocks propagating downstream.

  1. Broadband radio circular polarization spectrum of the relativistic jet in PKS B2126-158

    CERN Document Server

    O'Sullivan, S P; Feain, I J; Gaensler, B M; Sault, R J

    2013-01-01

    We present full-Stokes radio polarization observations of the quasar PKS B2126-158 (z=3.268) from 1 to 10 GHz using the Australia Telescope Compact Array. The source has large fractional circular polarization, m_c \\equiv |V|/I, detected at high significance across the entire band (from 15 to 90\\sigma per 128 MHz sub-band). This allows us to construct the most robust circular polarization (CP) spectrum of an AGN jet to date. We find m_c \\propto \

  2. Photonic radio-frequency phase shifter based on polarization interference.

    Science.gov (United States)

    Chen, Han; Dong, Yi; He, Hao; Hu, Weisheng; Li, Lemin

    2009-08-01

    An rf photonic phase shifter based on polarization interference is presented, and the theoretical fundamentals of the design are explained. This phase shifter provides broad operational bandwidth and a full 360 degrees phase-shift tuning range with a single external electrical control. A prototype of the rf photonic phase shifter with a frequency of 26.75 GHz and 360 degrees tuning range is experimentally demonstrated.

  3. N-tupling the capacity of each polarization state in radio links by using electromagnetic vorticity

    CERN Document Server

    Tamburini, Fabrizio; Mari, Elettra; Parisi, Giuseppe; Spinello, Fabio; Oldoni, Matteo; Ravanelli, Roberto A; Coassini, Piero; Someda, Carlo G; Romanato, Filippo

    2013-01-01

    The congestion of the radio frequency bands imposes serious limitations on the capacity and capability of modern wireless information infrastructures. One approach to enable frequency re-use is to exploit other physical conserved quantities of the electromagnetic fields, such as the orbital angular momentum (OAM) in addition to linear momentum, which is exploited in present-day telecommunications. Whereas in the optical regime the increase of channel capacity by using OAM states was demonstrated recently, the receiving antennas in commercial radio links have a much smaller extent than the transmitted beam, making the signal reception and characterization of the OAM state demanding. Moreover, radio data transmission with more than two channels per polarization state at the same frequency for radio links is known to be notoriously difficult to realize even with multiport techniques, long antenna baselines and digital post-processing. Here we report results from an outdoor, proof of concept experiment where the ...

  4. Measurement of radio emission from extensive air showers with LOPES

    Energy Technology Data Exchange (ETDEWEB)

    Hoerandel, J.R., E-mail: j.horandel@astro.ru.n [Radboud University Nijmegen, Department of Astrophysics, P.O. Box 9010, 6500 GL Nijmegen (Netherlands); Apel, W.D. [Institut fuer Kernphysik, Forschungszentrum Karlsruhe (Germany); Arteaga, J.C. [Institut fuer Experimentelle Kernphysik, Universitaet Karlsruhe (Germany); Asch, T. [IPE, Forschungszentrum Karlsruhe (Germany); Badea, F. [Institut fuer Kernphysik, Forschungszentrum Karlsruhe (Germany); Baehren, L. [Radboud University Nijmegen, Department of Astrophysics, P.O. Box 9010, 6500 GL Nijmegen (Netherlands); Bekk, K. [Institut fuer Kernphysik, Forschungszentrum Karlsruhe (Germany); Bertaina, M. [Dipartimento di Fisica Generale dell' Universita di Torino (Italy); Biermann, P.L. [Max-Planck-Institut fuer Radioastronomie Bonn (Germany); Bluemer, J. [Institut fuer Kernphysik, Forschungszentrum Karlsruhe (Germany); Institut fuer Experimentelle Kernphysik, Universitaet Karlsruhe (Germany); Bozdog, H. [Institut fuer Kernphysik, Forschungszentrum Karlsruhe (Germany); Brancus, I.M. [National Institute of Physics and Nuclear Engineering, Bucharest (Romania); Brueggemann, M.; Buchholz, P. [Fachbereich Physik, Universitaet Siegen (Germany); Buitink, S. [Radboud University Nijmegen, Department of Astrophysics, P.O. Box 9010, 6500 GL Nijmegen (Netherlands); Cantoni, E. [Dipartimento di Fisica Generale dell' Universita di Torino (Italy); Istituto di Fisica dello Spazio Interplan etario, INAF Torino (Italy); Chiavassa, A. [Dipartimento di Fisica Generale dell' Universita di Torino (Italy); Cossavella, F. [Institut fuer Experimentelle Kernphysik, Universitaet Karlsruhe (Germany); Daumiller, K. [Institut fuer Kernphysik, Forschungszentrum Karlsruhe (Germany); Souza, V. de [Institut fuer Experimentelle Kernphysik, Universitaet Karlsruhe (Germany)

    2011-02-21

    A new method is explored to detect extensive air showers: the measurement of radio waves emitted during the propagation of the electromagnetic shower component in the magnetic field of the Earth. Recent results of the pioneering experiment LOPES are discussed. It registers radio signals in the frequency range between 40 and 80 MHz. The intensity of the measured radio emission is investigated as a function of different shower parameters, such as shower energy, angle of incidence, and distance to shower axis. In addition, new antenna types are developed in the framework of LOPES{sup star} and new methods are explored to realize a radio self-trigger algorithm in real time.

  5. Measurement of Radio Emission from Extensive Air Showers with LOPES

    CERN Document Server

    Hoerandel, J R

    2009-01-01

    A new method is explored to detect extensive air showers: the measurement of radio waves emitted during the propagation of the electromagnetic shower component in the magnetic field of the Earth. Recent results of the pioneering experiment LOPES are discussed. It registers radio signals in the frequency range between 40 and 80 MHz. The intensity of the measured radio emission is investigated as a function of different shower parameters, such as shower energy, angle of incidence, and distance to shower axis. In addition, new antenna types are developed in the framework of LOPES-Star and new methods are explored to realize a radio self-trigger algorithm in real time.

  6. Radio emission from RS CVn binaries. II. Polarization and spectral properties

    Energy Technology Data Exchange (ETDEWEB)

    Mutel, R.L.; Morris, D.H.; Doiron, D.J.; Lestrade, J.F.

    1987-05-01

    Multiepoch radio observations of circular polarization and spectral characteristics of several close, late-type stellar binaries are reported. The median luminosity of four well-studied systems ranged from 16.2 to 17.1 ergs/s/Hz. For individual systems, the fractional circular polarization decreases with increasing luminosity, particularly at frequencies above 5 GHz. Eclipsing binaries have significantly lower average circular polarization compared with noneclipsing systems. Helicity reversal is almost always observed between 1.4 and 4.9 GHz for systems with high orbital inclination. Comparison with ten years of previously published polarization observations for two RS CVn stellar systems show that the same helicity occurs at a given frequency for a given source, indicating a very stable, large-scale magnetic field geometry. These spectral and polarization characteristics strongly support a model of inhomogeneous gyrosynchrotron emission arising from electrons with power law energy spectra interacting with inhomogeneous magnetic fields. 35 references.

  7. Finding a faint polarized signal in wide-band radio data

    Science.gov (United States)

    Schnitzeler, D. H. F. M.; Lee, K. J.

    2017-04-01

    We develop two algorithms, based on maximum likelihood inference, for estimating the parameters of polarized radio sources which emit at a single rotation measure (RM), e.g. pulsars. These algorithms incorporate the flux density spectrum of the source, either a power law or a scaled version of the Stokes I spectrum, and a variation in sensitivity across the observing band. We quantify the detection significance and measurement uncertainties in the fitted parameters, and we derive weighted versions of the RM synthesis algorithm which, under certain conditions, maximize the likelihood. We use Monte Carlo simulations to compare injected and recovered source parameters for a range of signal-to-noise ratios, investigate the quality of standard methods for estimating measurement uncertainties and search for statistical biases. These simulations consider one frequency band each for the Australia Telescope Compact Array, the Square Kilometre Array (SKA) and the Low Frequency Array. We find that results obtained for one frequency band cannot be easily generalized, and that methods that were developed in the past for correcting bias in individual frequency channels do not apply to wide-band data sets. The standard method for estimating the measurement uncertainty in RM is not accurate for sources with non-zero spectral indices. Furthermore, dividing Stokes Q and U by Stokes I to correct for spectral index effects, in combination with RM synthesis, does not maximize the likelihood.

  8. Superficial microcirculation flow measurement using polarized light

    Science.gov (United States)

    Wu, Jiwei; Morgan, S. P.; Xiao, Yunshi

    2008-12-01

    Depth discrimination of polarized light is used in investigating laser Doppler measurement of the superficial microcirculation in tissue. Using polarization Monte Carlo simulation, temporal point spread function and power spectral distribution of backscattered polarization remaining light firstly are used to prove polarized light to be valid in measuring moving blood cell perfusion and mean flow velocity. Then simulation of layered medium model demonstrate that relationships between blood flow perfusion and mean frequency shift are linear to medium flowing velocity, and the Doppler shift information in polarization remaining light mainly comes from lower layer medium up to about 14 times of mean free path (MFP) of medium investigated and can be considered that Doppler effects come only from lower layer of the medium. Simulations in three-layer tissue model show that moving blood cell perfusion and mean blood cell moving velocity calculated from polarization remaining are much more sensitive to lower layer flow velocity variation, and more irrelevant to deeper layer flow rate fluctuations, that further confirms Doppler measurement from polarization remaining light to be effective for superficial microcirculation in tissue. Factors affecting Laser Doppler measurement like medium absorption, percentage of moving particles in blood detector size are discussed.

  9. A Highly Circularly Polarized Solar Radio Emission Component Observed at Hectometric Wavelengths

    Science.gov (United States)

    Reiner, M. J.; Kaiser, M. L.; Fainberg, J.; Bougeret, J.-L.

    2006-04-01

    We report here the observation of a rare solar radio event at hectometric wavelengths that was characterized by essentially 100% circularly polarized radiation and that was observed continuously for about six days, from May 17 to 23, 2002. This was the first time that a solar source with significantly polarized radiation was detected by the WAVES experiment on the Wind spacecraft. From May 19 to 22, the intense polarized radio emissions were characterized by quasi-periodic intensity variations with periods from one to two hours and with superposed drifting, narrowband, fine structures. The bandwidth of this radiation extended from about 400 kHz to 7 MHz, and the peak frequency of the frequency spectrum slowly decreased from 2 MHz to about 0.8 MHz over the course of four days. The radio source, at each frequency, was observed to slowly drift from east to west about the Sun, as viewed from the Earth and was estimated to lie between 26 and 82 R ⊙ ( R ⊙ = 696 000 km). We speculate that this unusual event may represent an interplanetary manifestation of a moving type IV burst and discuss possible radio emission mechanisms. The ISEE-3 spacecraft may possibly have detected a similar event some 26 years ago.

  10. Measurement of $\\Lambda$ polarization from Z decays

    CERN Document Server

    Buskulic, Damir; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Odier, P; Pietrzyk, B; Chmeissani, M; Crespo, J M; Delfino, M C; Efthymiopoulos, I; Fernández, E; Fernández-Bosman, M; Garrido, L; Juste, A; Martínez, M; Orteu, S; Pacheco, A; Padilla, C; Palla, Fabrizio; Pascual, A; Perlas, J A; Riu, I; Sánchez, F; Teubert, F; Colaleo, A; Creanza, D; De Palma, M; Farilla, A; Gelao, G; Girone, M; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Natali, S; Nuzzo, S; Ranieri, A; Raso, G; Romano, F; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Alemany, R; Bazarko, A O; Bonvicini, G; Cattaneo, M; Comas, P; Coyle, P; Drevermann, H; Forty, Roger W; Frank, M; Hagelberg, R; Harvey, J; Jacobsen, R; Janot, P; Jost, B; Kneringer, E; Knobloch, J; Lehraus, Ivan; Martin, E B; Mato, P; Minten, Adolf G; Miquel, R; Mir, L M; Moneta, L; Oest, T; Palazzi, P; Pater, J R; Pusztaszeri, J F; Ranjard, F; Rensing, P E; Rolandi, Luigi; Schlatter, W D; Schmelling, M; Schneider, O; Tejessy, W; Tomalin, I R; Venturi, A; Wachsmuth, H W; Wagner, A; Wildish, T; Witzeling, W; Wotschack, J; Ajaltouni, Ziad J; Barrès, A; Boyer, C; Falvard, A; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Montret, J C; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rossignol, J M; Fearnley, Tom; Hansen, J B; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Wäänänen, A; Kyriakis, A; Markou, C; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Zachariadou, K; Blondel, A; Bonneaud, G R; Brient, J C; Bourdon, P; Rougé, A; Rumpf, M; Tanaka, R; Valassi, Andrea; Verderi, M; Videau, H L; Candlin, D J; Parsons, M I; Focardi, E; Parrini, G; Corden, M; Georgiopoulos, C H; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Casper, David William; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Passalacqua, L; Pepé-Altarelli, M; Curtis, L; Dorris, S J; Halley, A W; Knowles, I G; Lynch, J G; O'Shea, V; Raine, C; Reeves, P; Scarr, J M; Smith, K; Thompson, A S; Thomson, F; Thorn, S; Turnbull, R M; Becker, U; Geweniger, C; Graefe, G; Hanke, P; Hansper, G; Hepp, V; Kluge, E E; Putzer, A; Rensch, B; Schmidt, M; Sommer, J; Stenzel, H; Tittel, K; Werner, S; Wunsch, M; Abbaneo, D; Beuselinck, R; Binnie, David M; Cameron, W; Dornan, Peter J; Moutoussi, A; Nash, J; Sedgbeer, J K; Stacey, A M; Williams, M D; Dissertori, G; Girtler, P; Kuhn, D; Rudolph, G; Bowdery, C K; Brodbeck, T J; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Sloan, Terence; Whelan, E P; Williams, M I; Galla, A; Greene, A M; Kleinknecht, K; Quast, G; Renk, B; Rohne, E; Sander, H G; Van Gemmeren, P; Zeitnitz, C; Aubert, Jean-Jacques; Bencheikh, A M; Benchouk, C; Bonissent, A; Bujosa, G; Calvet, D; Carr, J; Diaconu, C A; Etienne, F; Konstantinidis, N P; Nicod, D; Payre, P; Rousseau, D; Talby, M; Sadouki, A; Thulasidas, M; Trabelsi, K; Abt, I; Assmann, R W; Bauer, C; Blum, Walter; Dietl, H; Dydak, Friedrich; Ganis, G; Gotzhein, C; Jakobs, K; Kroha, H; Lütjens, G; Lutz, Gerhard; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Schael, S; Settles, Ronald; Seywerd, H C J; Saint-Denis, R; Wiedenmann, W; Wolf, G; Boucrot, J; Callot, O; Cordier, A; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Jacquet, M; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Nikolic, I A; Park, H J; Park, I C; Schune, M H; Simion, S; Veillet, J J; Videau, I; Azzurri, P; Bagliesi, G; Batignani, G; Bettarini, S; Bozzi, C; Calderini, G; Carpinelli, M; Ciocci, M A; Ciulli, V; Dell'Orso, R; Fantechi, R; Ferrante, I; Foà, L; Forti, F; Giassi, A; Giorgi, M A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Rizzo, G; Sanguinetti, G; Sciabà, A; Spagnolo, P; Steinberger, Jack; Tenchini, Roberto; Tonelli, G; Vannini, C; Verdini, P G; Walsh, J; Betteridge, A P; Blair, G A; Bryant, L M; Cerutti, F; Chambers, J T; Gao, Y; Green, M G; Johnson, D L; Medcalf, T; Perrodo, P; Strong, J A; Von Wimmersperg-Töller, J H; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Maley, P; Norton, P R; Thompson, J C; Wright, A E; Bloch-Devaux, B; Colas, P; Emery, S; Kozanecki, Witold; Lançon, E; Lemaire, M C; Locci, E; Marx, B; Pérez, P; Rander, J; Renardy, J F; Roussarie, A; Schuller, J P; Schwindling, J; Trabelsi, A; Vallage, B; Johnson, R P; Kim, H Y; Litke, A M; McNeil, M A; Taylor, G; Beddall, A; Booth, C N; Boswell, R; Brew, C A J; Cartwright, S L; Combley, F; Köksal, A; Letho, M; Newton, W M; Rankin, C; Reeve, J; Thompson, L F; Böhrer, A; Brandt, S; Büscher, V; Cowan, G D; Grupen, Claus; Lutters, G; Minguet-Rodríguez, J A; Rivera, F; Saraiva, P; Smolik, L; Stephan, F; Aleppo, M; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Musolino, G; Ragusa, F; Rothberg, J E; Wasserbaech, S R; Armstrong, S R; Bellantoni, L; Elmer, P; Feng, Z; Ferguson, D P S; Gao, Y S; González, S; Grahl, J; Greening, T C; Harton, J L; Hayes, O J; Hu, H; McNamara, P A; Nachtman, J M; Orejudos, W; Pan, Y B; Saadi, Y; Schmitt, M; Scott, I J; Sharma, V; Turk, J; Walsh, A M; Wu, X; Yamartino, J M; Zheng, M; Zobernig, G

    1996-01-01

    The polarization of \\Lambda baryons from Z decays is studied with the {\\sc Aleph} apparatus. Evidence of longitudinal polarization of s quarks from Z decay is observed for the first time. The measured longitudinal \\Lambda polarization is P^{\\Lambda}_{L} = -0.32 \\pm 0.07 for z = p/p_{\\mathrm{beam}} > 0.3. This agrees with the prediction of -0.39 \\pm 0.08 from the standard model and the constituent quark model, where the error is due to uncertainties in the mechanism for \\Lambda production. The observed \\Lambda polarization is diluted with respect to the primary s quark polarization by \\Lambda baryons without a primary s quark. Measurements of the \\Lambda forward-backward asymmetry and of the correlation between back-to-back \\Lambda \\bar{\\Lambda} pairs are used to check this dilution. In addition the transverse \\Lambda polarization is measured. An indication of transverse polarization, more than two standard deviations away from zero, is found along the normal to the plane defined by the thrust axis and the \\La...

  11. Hubble Space Telescope NICMOS Polarization Measurements of OMC-1

    CERN Document Server

    Simpson, J P; Colgan, S W J; Erickson, E F; Schultz, A S B; Burton, Michael G.; Colgan, Sean W. J.; Erickson, Edwin F.; Simpson, Janet P.

    2006-01-01

    We present 2micron polarization measurements of positions in the BN region of the Orion Molecular Cloud (OMC-1) made with NICMOS Camera 2 (0.2'' resolution) on HST. Our results are as follows: BN is sim 29% polarized by dichroic absorption and appears to be the illuminating source for most of the nebulosity to its north and up to sim 5'' to its south. Although the stars are probably all polarized by dichroic absorption, there are a number of compact, but non-point-source, objects that could be polarized by a combination of both dichroic absorption and local scattering of star light. We identify several candidate YSOs, including an approximately edge-on bipolar YSO 8.7'' east of BN, and a deeply-embedded variable star. Additional strongly polarized sources are IRc2-B, IRc2-D, and IRc7, all of which are obviously self-luminous at mid-infrared wavelengths and may be YSOs. None of these is a reflection nebula illuminated by a star located near radio source I, as was previously suggested. Other IRc sources are cle...

  12. Physical Conditions and Variability Processes in AGN Jets through Multi-Frequency Linear and Circular Radio Polarization Monitoring

    CERN Document Server

    Myserlis, Ioannis; Kraus, Alex; Fuhrmann, Lars; Karamanavis, Vassilis; Zensus, J Anton

    2016-01-01

    Radio polarimetry is an invaluable tool to investigate the physical conditions and variability processes in active galactic nuclei (AGN) jets. However, detecting their linear and circular polarization properties is a challenging endeavor due to their low levels and possible depolarization effects. We have developed an end-to-end data analysis methodology to recover the polarization properties of unresolved sources with high accuracy. It has been applied to recover the linear and circular polarization of 87 AGNs measured by the F-GAMMA program from July 2010 to January 2015 with a mean cadence of 1.3 months. Their linear polarization was recovered at four frequencies between 2.64 and 10.45 GHz and the circular polarization at 4.85 and 8.35 GHz. The physical conditions required to reproduce the observed polarization properties and the processes which induce their variability were investigated with a full-Stokes radiative transfer code which emulates the synchrotron emission of modeled jets. The model was used t...

  13. Are there real orthogonal polarization modes in pulsar radio emission?

    Institute of Scientific and Technical Information of China (English)

    徐仁新; 乔国俊

    2000-01-01

    The orthogonal polarization modes (OPM) have been reported observationally and widely accepted by pulsar researchers. However, no acceptable theory can explain the origin of the OPM, which becomes a mystery in pulsar research field. Here a possible way to solve this mystery is pre-sented. We ask a question: Does there exist any real so-called OPM in pulsar radiation? It is proposed that the ’observed OPM’ in individual pulses could be the results of depolarization of pulsar radiation and the observational uncertainties originated f rom polarimeter in observation. A possible method to check this idea is suggested. If the idea is verified, the pulsar research would be influenced significant-ly in theory and in observation.

  14. Are there real orthogonal polarization modes in pulsar radio emission?

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The orthogonal polarization modes (OPM) have been reported observationally and widely accepted by pulsar researchers. However, no acceptable theory can explain the origin of the OPM, which becomes a mystery in pulsar research field. Here a possible way to solve this mystery is presented. We ask a question: Does there exist any real so-called OPM in pulsar radiation? It is proposed that the 'observed OPM' in individual pulses could be the results of depolarization of pulsar radiation and the observational uncertainties originated from polarimeter in observation. A possible method to check this idea is suggested. If the idea is verified, the pulsar research would be influenced significantly in theory and in observation.

  15. Measurement of radio emission from extensive air showers with LOPES

    NARCIS (Netherlands)

    Horandel, J.R.; Apel, W.D.; Arteaga, J.C.; Asch, T.; Badea, F.; Bahren, L.; Bekk, K.; Bertaina, M.; Biermann, P.L.; Blumer, J.; Bozdog, H.; Brancus, I.M.; Bruggemann, M.; Buchholz, P.; Buitink, S.; Cantoni, E.; Chiavassa, A.; Cossavella, F.; Daumiller, K.; Souza, V. de; Pierro, F. di; Doll, P.; Ender, M.; Engel, R.; Falcke, H.; Finger, M.; Fuhrmann, D.; Gemmeke, H.; Ghia, P.L.; Glasstetter, R.; Grupen, C.; Haungs, A.; Heck, D.; Horneffer, A.; Huege, T.; Isar, P.G.; Kampert, K.H.; Kang, D.; Kickelbick, D.; Kromer, O.; Kuijpers, J; Lafebre, S.J.; Link, K.; Luczak, P.; Ludwig, M.; Mathes, H.J.; Mayer, H.J.; Melissas, M.; Mitrica, B.; Morello, C.; Navarra, G.; Nehls, S.; Nigl, A.; Oehlschlager, J.; Over, S.; Palmieri, N.; Petcu, M.; Pierog, T.; Rautenberg, J.; Rebel, H.; Roth, M.; Saftoiu, A.; Schieler, H.; Schmidt, A.; Schroder, F.; Sima, O.; Singh, K.; Toma, G.; Trinchero, G.C.; Ulrich, H.; Weindl, A.; Wochele, J.; Wommer, M.; Zabierowski, J.; Zensus, J.A.

    2011-01-01

    A new method is explored to detect extensive air showers: the measurement of radio waves emitted during the propagation of the electromagnetic shower component in the magnetic field of the Earth. Recent results of the pioneering experiment LOPES are discussed. It registers radio signals in the frequ

  16. FREQUENCY DEPENDENCE OF POLARIZATION OF ZEBRA PATTERN IN TYPE-IV SOLAR RADIO BURSTS

    Energy Technology Data Exchange (ETDEWEB)

    Kaneda, Kazutaka; Misawa, H.; Tsuchiya, F.; Obara, T. [Planetary Plasma and Atmospheric Research Center, Tohoku University, Sendai, Miyagi 980-8578 (Japan); Iwai, K., E-mail: k.kaneda@pparc.gp.tohoku.ac.jp [National Institute of Information and Communications Technology, 4-2-1, Nukui-Kitamachi, Koganei, Tokyo 184-8795 (Japan)

    2015-08-01

    We investigated the polarization characteristics of a zebra pattern (ZP) in a type-IV solar radio burst observed with AMATERAS on 2011 June 21 for the purpose of evaluating the generation processes of ZPs. Analyzing highly resolved spectral and polarization data revealed the frequency dependence of the degree of circular polarization and the delay between two polarized components for the first time. The degree of circular polarization was 50%–70% right-handed and it varied little as a function of frequency. Cross-correlation analysis determined that the left-handed circularly polarized component was delayed by 50–70 ms relative to the right-handed component over the entire frequency range of the ZP and this delay increased with the frequency. We examined the obtained polarization characteristics by using pre-existing ZP models and concluded that the ZP was generated by the double-plasma-resonance process. Our results suggest that the ZP emission was originally generated in a completely polarized state in the O-mode and was partly converted into the X-mode near the source. Subsequently, the difference between the group velocities of the O-mode and X-mode caused the temporal delay.

  17. Frequency Dependence of Polarization of Zebra Pattern in Type-IV Solar Radio Bursts

    CERN Document Server

    Kaneda, Kazutaka; Iwai, Kazumasa; Tsuchiya, Fuminori; Obara, Takahiro

    2015-01-01

    We investigated the polarization characteristics of a zebra pattern (ZP) in a type-IV solar radio burst observed with AMATERAS on 2011 June 21 for the purpose of evaluating the generation processes of ZP. Analyzing highly resolved spectral and polarization data revealed the frequency dependence of the degree of circular polarization and the delay between two polarized components for the first time. The degree of circular polarization was 50-70 percent right-handed and it varied little as a function of frequency. Cross-correlation analysis determined that the left-handed circularly polarized component was delayed by 50-70 ms relative to the right-handed component over the entire frequency range of the ZP and this delay increased with the frequency. We examined the obtained polarization characteristics by using pre-existing ZP models and concluded that the ZP was generated by the double plasma resonance process. Our results suggest that the ZP emission was originally generated in a completely polarized state in...

  18. Radio-frequency measurement in semiconductor quantum computation

    Science.gov (United States)

    Han, TianYi; Chen, MingBo; Cao, Gang; Li, HaiOu; Xiao, Ming; Guo, GuoPing

    2017-05-01

    Semiconductor quantum dots have attracted wide interest for the potential realization of quantum computation. To realize efficient quantum computation, fast manipulation and the corresponding readout are necessary. In the past few decades, considerable progress of quantum manipulation has been achieved experimentally. To meet the requirements of high-speed readout, radio-frequency (RF) measurement has been developed in recent years, such as RF-QPC (radio-frequency quantum point contact) and RF-DGS (radio-frequency dispersive gate sensor). Here we specifically demonstrate the principle of the radio-frequency reflectometry, then review the development and applications of RF measurement, which provides a feasible way to achieve high-bandwidth readout in quantum coherent control and also enriches the methods to study these artificial mesoscopic quantum systems. Finally, we prospect the future usage of radio-frequency reflectometry in scaling-up of the quantum computing models.

  19. Polarization measurement analysis III. Analysis of the polarization angle dispersion function with high precision polarization data

    CERN Document Server

    Alina, D; Ristorcelli, I; Bernard, J -P; Levrier, F; Abdikamalov, E

    2016-01-01

    High precision polarization measurements open new opportunities for the study of the magnetic field structure as traced by polarimetric measurements of the interstellar dust emission. Polarization parameters suffer from bias in the presence of measurement noise. It is critical to take into account all the information available in the data in order to accurately derive these parameters. The goal of this paper is to characterize the bias on the polarization angle dispersion function that is used to study the spatial coherence of the polarization angle. We characterize, for the first time, the bias on the conventional estimator of the polarization angle dispersion function (S hereafter) and show that it can be positive or negative depending on the true value. Monte Carlo simulations are performed in order to explore the impact of the noise properties of the polarization data, as well as the impact of the distribution of the true polarization angles on the bias. We show that in the case where the ellipticity of t...

  20. Mapping the Polarization of the Radio-Loud Ly$\\alpha$ Nebula B3 J2330+3927

    CERN Document Server

    You, Chang; Smith, Paul; Yang, Yujin; Kim, Eunchong; Jannuzi, Buell; Prescott, Moire K M; Matsuda, Yuichi; Lee, Myung Gyoon

    2016-01-01

    Lya nebulae, or "Lya blobs", are extended (up to ~100 kpc), bright (L[Lya] > 10^43 erg/s) clouds of Lya emitting gas that tend to lie in overdense regions at z ~ 2--5. The origin of the Lya emission remains unknown, but recent theoretical work suggests that measuring the polarization might discriminate among powering mechanisms. Here we present the first narrowband, imaging polarimetry of a radio-loud Lya nebula, B3 J2330+3927 at z=3.09, with an embedded active galactic nucleus (AGN). The AGN lies near the blob's Lya emission peak and its radio lobes align roughly with the blob's major axis. With the SPOL polarimeter on the 6.5m MMT telescope, we map the total (Lya + continuum) polarization in a grid of circular apertures of radius 0.6" (4.4kpc), detecting a significant (>2sigma) polarization fraction P in nine apertures and achieving strong upper-limits (as low as 2%) elsewhere. P increases from <2% at ~5kpc from the blob center to ~17% at ~15-25kpc. The detections are distributed asymmetrically, roughly ...

  1. Polarization measurement of laser-accelerated protons

    Energy Technology Data Exchange (ETDEWEB)

    Raab, Natascha; Engels, Ralf; Engin, Ilhan; Greven, Patrick; Holler, Astrid; Lehrach, Andreas; Maier, Rudolf [Institut für Kernphysik and Jülich Center for Hadron Physics, Forschungszentrum Jülich, 52425 Jülich (Germany); Büscher, Markus, E-mail: m.buescher@fz-juelich.de [Institut für Kernphysik and Jülich Center for Hadron Physics, Forschungszentrum Jülich, 52425 Jülich (Germany); Peter Grünberg Institut (PGI-6), Forschungszentrum Jülich, 52425 Jülich (Germany); Institute for Laser- and Plasma Physics, Heinrich-Heine Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf (Germany); Cerchez, Mirela; Swantusch, Marco; Toncian, Monika; Toncian, Toma; Willi, Oswald [Institute for Laser- and Plasma Physics, Heinrich-Heine Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf (Germany); Gibbon, Paul; Karmakar, Anupam [Institute for Advanced Simulation, Jülich Supercomputing Centre, Forschungszentrum Jülich, 52425 Jülich (Germany)

    2014-02-15

    We report on the successful use of a laser-driven few-MeV proton source to measure the differential cross section of a hadronic scattering reaction as well as on the measurement and simulation study of polarization observables of the laser-accelerated charged particle beams. These investigations were carried out with thin foil targets, illuminated by 100 TW laser pulses at the Arcturus laser facility; the polarization measurement is based on the spin dependence of hadronic proton scattering off nuclei in a Silicon target. We find proton beam polarizations consistent with zero magnitude which indicates that for these particular laser-target parameters the particle spins are not aligned by the strong magnetic fields inside the laser-generated plasmas.

  2. When measured spin polarization is not spin polarization

    Science.gov (United States)

    Dowben, P. A.; Wu, Ning; Binek, Christian

    2011-05-01

    Spin polarization is an unusually ambiguous scientific idiom and, as such, is rarely well defined. A given experimental methodology may allow one to quantify a spin polarization but only in its particular context. As one might expect, these ambiguities sometimes give rise to inappropriate interpretations when comparing the spin polarizations determined through different methods. The spin polarization of CrO2 and Cr2O3 illustrate some of the complications which hinders comparisons of spin polarization values.

  3. Radio emission of air showers with extremely high energy measured by the Yakutsk Radio Array

    Science.gov (United States)

    Knurenko, S. P.; Petrov, Z. E.; Petrov, I. S.

    2017-09-01

    The Yakutsk Array is designed to study cosmic rays at energy 1015 -1020 eV . It consists several independent arrays that register charged particles, muons with energy E ≥ 1 GeV , Cherenkov light and radio emission. The paper presents a technical description of the Yakutsk Radio Array and some preliminary results obtained from measurements of radio emission at 30-35 MHz frequency induced by air shower particles with energy ε ≥ 1 ·1017 eV . The data obtained at the Yakutsk array in 1986-1989 (first set of measurements) and 2009-2014 (new set of measurements). Based on the obtained results we determined: Lateral distribution function (LDF) of air showers radio emission with energy ≥1017 eV . Radio emission amplitude empirical connection with air shower energy. Determination of depth of maximum by ratio of amplitude at different distances from the shower axis. For the first time, at the Yakutsk array radio emission from the air shower with energy >1019 eV was registered including the shower with the highest energy ever registered at the Yakutsk array with energy ∼ 2 ·1020 eV .

  4. Reconfigurable Wideband Circularly Polarized Stacked Square Patch Antenna for Cognitive Radios

    Science.gov (United States)

    Barbosa Kortright, Miguel A.; Waldstein, Seth W.; Simons, Rainee N.

    2017-01-01

    An almost square patch, a square patch and a stacked square patch with corner truncation for circular polarization (CP) are researched and developed at X-band for cognitive radios. Experimental results indicate, first, that the impedance bandwidth of a CP almost square patch fed from the edge by a 50 ohm line is 1.70% and second, that of a CP square patch fed from the ground plane side by a surface launch connector is 1.87%. Third, the impedance bandwidth of a CP stacked square patch fed by a surface launch connector is 2.22%. The measured center frequency for the CP square patch fed by a surface launch connector without and with an identical stacked patch is 8.45 and 8.1017 GHz, respectively. By stacking a patch, separated by a fixed air gap of 0.254 mm, the center frequency is observed to shift by as much as 348.3 MHz. The shift in center frequency, brought about by the reconfiguring of the physical layer antenna, can be exploited in a cognitive system since it expands the usable frequency spectrum for software reconfiguration in the presence of interference. In addition, varying the fixed air gap in the stacked antenna geometry by increments of 0.254 mm further expands the usable frequency spectrum.

  5. The application of compressive sampling to radio astronomy II: Faraday rotation measure synthesis

    CERN Document Server

    Li, Feng; Cornwell, Tim J; de Hoog, Frank

    2011-01-01

    Faraday rotation measure (RM) synthesis is an important tool to study and analyze galactic and extra-galactic magnetic fields. Since there is a Fourier relation between the Faraday dispersion function and the polarized radio emission, full reconstruction of the dispersion function requires knowledge of the polarized radio emission at both positive and negative square wavelengths $\\lambda^2$. However, one can only make observations for $\\lambda^2 > 0$. Furthermore observations are possible only for a limited range of wavelengths. Thus reconstructing the Faraday dispersion function from these limited measurements is ill-conditioned. In this paper, we propose three new reconstruction algorithms for RM synthesis based upon compressive sensing/sampling (CS). These algorithms are designed to be appropriate for Faraday thin sources only, thick sources only, and mixed sources respectively. Both visual and numerical results show that the new RM synthesis methods provide superior reconstructions of both magnitude and p...

  6. Detection of Low-Lattitude Plumes in the Outer Corona by Ulysses Radio Ranging Measurements

    Science.gov (United States)

    Woo, Richard; Bird, Michael K.; Pold, Martin

    1996-01-01

    Plumes have been detected beyond the field of view of coronagraphs in the range of 23-42 R(sub o) in an equatorial coronal hole by Ulysses radio ranging measurements conducted in 1991 at 13 and 3.6 cm wavelengths. These results show that plumes are not exclusive to polar regions, but appear to be intrinsic to open magnetic field regions at any latitude.

  7. Detection of Low-Lattitude Plumes in the Outer Corona by Ulysses Radio Ranging Measurements

    Science.gov (United States)

    Woo, Richard; Bird, Michael K.; Pold, Martin

    1996-01-01

    Plumes have been detected beyond the field of view of coronagraphs in the range of 23-42 R(sub o) in an equatorial coronal hole by Ulysses radio ranging measurements conducted in 1991 at 13 and 3.6 cm wavelengths. These results show that plumes are not exclusive to polar regions, but appear to be intrinsic to open magnetic field regions at any latitude.

  8. Low-Mach-number turbulence in interstellar gas revealed by radio polarization gradients

    CERN Document Server

    Gaensler, Bryan M; Burkhart, Blakesley; Newton-McGee, Katherine J; Ekers, Ronald D; Lazarian, Alex; McClure-Griffiths, Naomi M; Robishaw, Timothy; Dickey, John M; Green, Anne J; 10.1038/nature10446

    2011-01-01

    The interstellar medium of the Milky Way is multi-phase, magnetized and turbulent. Turbulence in the interstellar medium produces a global cascade of random gas motions, spanning scales ranging from 100 parsecs to 1000 kilometres. Fundamental parameters of interstellar turbulence such as the sonic Mach number (the speed of sound) have been difficult to determine because observations have lacked the sensitivity and resolution to directly image the small-scale structure associated with turbulent motion. Observations of linear polarization and Faraday rotation in radio emission from the Milky Way have identified unusual polarized structures that often have no counterparts in the total radiation intensity or at other wavelengths, and whose physical significance has been unclear. Here we report that the gradient of the Stokes vector (Q,U), where Q and U are parameters describing the polarization state of radiation, provides an image of magnetized turbulence in diffuse ionized gas, manifested as a complex filamenta...

  9. First detection of 350 micron polarization from a radio-loud AGN

    CERN Document Server

    Lee, Sang-Sung; Byun, Do-Young; Chapman, Nicholas; Novak, Giles; Trippe, Sascha; Algaba, Juan Carlos; Kino, Motoki

    2015-01-01

    We report the first detection of linearly polarized emission at an observing wavelength of 350~$\\mu$m from the radio-loud Active Galactic Nucleus (AGN) 3C~279. We conducted polarization observations for 3C~279 using the SHARP polarimeter in the Caltech Submillimeter Observatory (CSO) on 2014 March 13 and 14. For the first time, we detected the linear polarization with the degree of polarization of 13.3\\%$\\pm$3.4\\% {\\bf($3.9\\sigma$)} and the Electric Vector Position Angle (EVPA) of 34.7$^\\circ\\pm5.6^\\circ$. We also observed 3C~279 simultaneously at 22, 43, and 86~GHz in dual polarization with the Korean VLBI Network (KVN) on 2014 March 6 (single dish) and imaged in milliarcsecond (mas) scales at 22, 43, 86, and 129~GHz on March 22 (VLBI). We found that the degree of linear polarization increases from 10\\% to 13\\% at 22~GHz to 350~$\\mu$m and the EVPAs at all observing frequencies are parallel within $<10^\\circ$ to the direction of the jet at mas scale, implying that the integrated magnetic fields are perpend...

  10. Detection of Transionospheric SuperDARN HF Waves by the Radio Receiver Instrument on the enhanced Polar Outflow Probe Satellite

    Science.gov (United States)

    Gillies, R. G.; Yau, A. W.; James, H. G.; Hussey, G. C.; McWilliams, K. A.

    2014-12-01

    The enhanced Polar Outflow Probe (ePOP) Canadian small-satellite was launched in September 2013. Included in this suite of eight scientific instruments is the Radio Receiver Instrument (RRI). The RRI has been used to measure VLF and HF radio waves from various ground and spontaneous ionospheric sources. The first dedicated ground transmission that was detected by RRI was from the Saskatoon Super Dual Auroral Radar Network (SuperDARN) radar on Nov. 7, 2013 at 14 MHz. Several other passes over the Saskatoon SuperDARN radar have been recorded since then. Ground transmissions have also been observed from other radars, such as the SPEAR, HAARP, and SURA ionospheric heaters. However, the focus of this study will be on the results obtained from the SuperDARN passes. An analysis of the signal recorded by the RRI provides estimates of signal power, Doppler shift, polarization, absolute time delay, differential mode delay, and angle of arrival. By comparing these parameters to similar parameters derived from ray tracing simulations, ionospheric electron density structures may be detected and measured. Further analysis of the results from the other ground transmitters and future SuperDARN passes will be used to refine these results.

  11. When measured spin polarization is not spin polarization

    Energy Technology Data Exchange (ETDEWEB)

    Dowben, P A; Wu Ning; Binek, Christian, E-mail: pdowben@unl.edu [Department of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, NE 68588-0299 (United States)

    2011-05-04

    Spin polarization is an unusually ambiguous scientific idiom and, as such, is rarely well defined. A given experimental methodology may allow one to quantify a spin polarization but only in its particular context. As one might expect, these ambiguities sometimes give rise to inappropriate interpretations when comparing the spin polarizations determined through different methods. The spin polarization of CrO{sub 2} and Cr{sub 2}O{sub 3} illustrate some of the complications which hinders comparisons of spin polarization values. (viewpoint)

  12. When measured spin polarization is not spin polarization.

    Science.gov (United States)

    Dowben, P A; Wu, Ning; Binek, Christian

    2011-05-04

    Spin polarization is an unusually ambiguous scientific idiom and, as such, is rarely well defined. A given experimental methodology may allow one to quantify a spin polarization but only in its particular context. As one might expect, these ambiguities sometimes give rise to inappropriate interpretations when comparing the spin polarizations determined through different methods. The spin polarization of CrO(2) and Cr(2)O(3) illustrate some of the complications which hinders comparisons of spin polarization values. © 2011 IOP Publishing Ltd

  13. Progress in Air Shower Radio Measurements: Detection of Distant Events

    CERN Document Server

    Apel, W D; Badea, A F; Bähren, L; Bekk, K; Bercuci, A; Bertaina, M; Biermann, P L; Blumer, J; Bozdog, H; Brancus, I M; Buitink, S; Bruggemann, M; Buchholz, P; Butcher, H; Chiavassa, A; Cossavella, F; Daumiller, K; Di Pierro, F; Doll, P; Engel, R; Falcke, H; Gemmeke, H; Ghia, P L; Glasstetter, R; Grupen, C; Haungs, A; Heck, D; Hörandel, J R; Horneffer, A; Huege, T; Kampert, K H; Kolotaev, Yu; Krömer, O; Kuijpers, J; Lafebre, S; Mathes, H J; Mayer, H J; Meurer, C; Milke, J; Mitrica, B; Morello, C; Navarra, G; Nehls, S; Nigl, A; Obenland, R; Oehlschläger, J; Ostapchenko, S; Over, S; Petcu, M; Petrovic, J; Pierog, T; Plewnia, S; Rebel, H; Risse, A; Roth, M; Schieler, H; Sima, O; Singh, K; Stumpert, M; Toma, G; Trinchero, G C; Ulrich, H; Van Buren, J; Walkowiak, W; Weindl, A; Wochele, J; Zabierowski, J; Zensus, J A; Zimmermann, D

    2006-01-01

    Data taken during half a year of operation of 10 LOPES antennas (LOPES-10), triggered by EAS observed with KASCADE-Grande have been analysed. We report about the analysis of correlations of radio signals measured by LOPES-10 with extensive air shower events reconstructed by KASCADE-Grande, including shower cores at large distances. The efficiency of detecting radio signals induced by air showers up to distances of 700 m from the shower axis has been investigated. The results are discussed with special emphasis on the effects of the reconstruction accuracy for shower core and arrival direction on the coherence of the measured radio signal. In addition, the correlations of the radio pulse amplitude with the primary cosmic ray energy and with the lateral distance from the shower core are studied.

  14. White Paper: Radio Emission and Polarization Properties of Galaxy Clusters with VLASS

    CERN Document Server

    Clarke, Tracy; Brown, Shea; Brunetti, Gianfranco; Cassano, Rossella; Dallacasa, Daniele; Feretti, Luigina; Giacintucci, Simona; Giovannini, Gabriele; Govoni, Federica; Markevitch, Maxim; Murgia, Matteo; Rudnick, Lawrence; Scaife, Anna; Vacca, Valentina; Venturi, Tiziana; van Weeren, Reinout

    2014-01-01

    We outline the science case for extended radio emission and polarization in galaxy clusters which would be a scientifically important area of research for an upcoming Jansky Very Large Array Sky Survey. The survey would provide a major contribution in three key areas of the physics of clusters: 1) the active galactic nucleus population and the impact of feedback on the evolution of the intra-cluster medium, 2) the origin and evolution of diffuse cluster radio sources to probe the physics of mergers with implications for cosmology, and 3) the origin and role of magnetic fields in the ICM and in large scale structures. Considering all three areas, a survey must have sufficient spatial resolution to study the tailed galaxies which trace the cluster weather as well as the radio lobes driving energy into the cluster from the central AGN. The survey must also have sensitivity to low surface brightness emission and large angular scales to probe radio halos and relics as well as the WHIM residing in the large scale s...

  15. Data Analysis And Polarization Measurements With GEMS

    Science.gov (United States)

    Stohmayer, Tod

    2011-01-01

    The Gravity and Extreme Magnetism SMEX (GEMS) mission was selected by NASA for flight in 2014. GEMS will make the first sensitive survey of X-ray polarization across a wide range of source classes including black hole and neutron star binaries, AGN of different types, rotation and accretion-powered pulsars, magnetars, shell supernova remnants and pulsar wind nebulae. GEMS employs grazing-incidence foil mirrors and novel time-projection chamber (TPC) polarimeters leveraging the photoelectric effect. The GEMS detectors image the charge tracks of photoelectrons produced by 2 - 10 keV X-rays. The initial direction of the photoelectron is determined by the linear polarization of the photon. We present an overview of the data analysis challenges and methods for GEMS, including procedures for producing optimally filtered images of the charge tracks and estimating their initial directions. We illustrate our methods using laboratory measurements of polarized and unpolarized X-rays with flight-like detectors as well as from simulated tracks. We also present detailed simulations exploring the statistics of polarization measurements appropriate for GEMS, and make comparisons with previous work.

  16. Long-term Periodicity Analysis of Polarization Variation for Radio Sources

    Indian Academy of Sciences (India)

    Yuhai Yuan

    2011-03-01

    We use the database of University of Michigan Radio Astronomy Observatory (UMRAO) at three radio bands (4.8, 8 and 14.5 GHz) to analyse the long-term polarization variation in search of the possible periodicity. Using the power spectral analysis method (PSA), the Jurkevich method and the discrete correlation function (DCF) method, we find that there are 16 sources lying in periodicity. The results show the astrophysically meaningful periodicity covering 2.1 years to 16.2 years at 4.8 GHz, 2.8 years to 16.3 years at 8 GHz, and 1.8 years to 16.6 years at 14.5 GHz.

  17. Majorization and Measures of Classical Polarization in Three Dimensions

    CERN Document Server

    Gamel, Omar

    2014-01-01

    There has been much discussion in the literature about rival measures of classical polarization in three dimensions. We gather and compare the various proposed measures of polarization, creating a geometric representation of the polarization state space in the process. We use majorization, previously used in quantum information, as a criterion to establish a partial ordering on the polarization state space. An additional criterion of analogous polarization states based on the di?fferences between eigenvalues of the polarization matrix is introduced. Using these criteria and other considerations, the most useful polarization measure in three dimensions is found to be one dependent on the Bloch vector decomposition of the polarization matrix.

  18. GRB Polarization Measurements with CGRO/COMPTEL

    Science.gov (United States)

    McConnell, Mark L.; Collmar, Werner

    2016-04-01

    We have embarked on a program to analyze CGRO/COMPTEL data in search for evidence of polarization in both transient sources and in brighter steady sources. We are pursuing this work because of the heightened interest in high energy polarimetry, the recognition that some high energy sources may be highly polarized (thus improving our chances of a making useful measurements), and the ready availability of modern computing resources that provide the ability to carry out more comprehensive simulations in support of the analysis. The only significant work done to date with regards to COMPTEL polarimetry was published almost 20 years ago and used a simplified mass model of COMPTEL for simulating the instrument response. Estimates of the minimum detectable polarization (MDP) near 1 MeV included 30% for a two-week observation of the Crab, as low as 10% for bright GRBs, and as low as 10% for bright solar flares. The data analysis performed at the time led to inconclusive results and suggested some unknown systematic error. We contend that a self-consistent analysis will be feasible with high fidelity simulations, simulations that were not easily generated 20 years ago. Our analysis utilizes the latest GEANT4 simulation tools in conjunction with a high-fidelity mass model of the COMPTEL instrument, and incorporate updated analysis tools originally developed by the COMPTEL collaboration. Given the nine years of COMPTEL data, we expect that this work will likely add to our understanding of the polarization properties of transient sources, such as GRBs and solar flares, as well as brighter steady sources, such as the Crab and Cyg X-1. Here we present results from simulations of the COMPTEL polarization response and examine prospects for studying GRB polarization.

  19. The Tunka radio extension (Tunka-Rex): Radio measurements of cosmic rays in Siberia

    Science.gov (United States)

    Schröder, F. G.; Bezyazeekov, P. A.; Budnev, N. M.; Gress, O. A.; Haungs, A.; Hiller, R.; Huege, T.; Kazarina, Y.; Kleifges, M.; Konstantinov, E. N.; Korosteleva, E. E.; Kostunin, D.; Krömer, O.; Kuzmichev, L. A.; Lubsandorzhiev, N.; Mirgazov, R. R.; Monkhoev, R.; Pakhorukov, A.; Pankov, L.; Prosin, V. V.; Rubtsov, G. I.; Wischnewski, R.; Zagorodnikov, A.

    2016-07-01

    The Tunka observatory is located close to Lake Baikal in Siberia, Russia. Its main detector, Tunka-133, is an array of photomultipliers measuring Cherenkov light of air showers initiated by cosmic rays in the energy range of approximately 1016 -1018 eV. In the last years, several extensions have been built at the Tunka site, e.g., a scintillator array named Tunka-Grande, a sophisticated air-Cherenkov-detector prototype named HiSCORE, and the radio extension Tunka-Rex. Tunka-Rex started operation in October 2012 and currently features 44 antennas distributed over an area of about 3km2, which measure the radio emission of the same air showers detected by Tunka-133 and Tunka-Grande. Tunka-Rex is a technological demonstrator that the radio technique can provide an economic extension of existing air-shower arrays. The main scientific goal is the cross-calibration with the air-Cherenkov measurements. By this cross-calibration, the precision for the reconstruction of the energy and mass of the primary cosmic-ray particles can be determined. Finally, Tunka-Rex can be used for cosmic-ray physics at energies close to 1 EeV, where the standard Tunka-133 analysis is limited by statistics. In contrast to the air-Cherenkov measurements, radio measurements are not limited to dark, clear nights and can provide an order of magnitude larger exposure.

  20. Status of air-shower measurements with sparse radio arrays

    Science.gov (United States)

    Schröder, Frank G.

    2017-03-01

    This proceeding gives a summary of the current status and open questions of the radio technique for cosmic-ray air showers, assuming that the reader is already familiar with the principles. It includes recent results of selected experiments not present at this conference, e.g., LOPES and TREND. Current radio arrays like AERA or Tunka-Rex have demonstrated that areas of several km2 can be instrumented for reasonable costs with antenna spacings of the order of 200m. For the energy of the primary particle such sparse antenna arrays can already compete in absolute accuracy with other precise techniques, like the detection of air-fluorescence or air-Cherenkov light. With further improvements in the antenna calibration, the radio detection might become even more accurate. For the atmospheric depth of the shower maximum, Xmax, currently only the dense array LOFAR features a precision similar to the fluorescence technique, but analysis methods for the radio measurement of Xmax are still under development. Moreover, the combination of radio and muon measurements is expected to increase the accuracy of the mass composition, and this around-the-clock recording is not limited to clear nights as are the light-detection methods. Consequently, radio antennas will be a valuable add-on for any air shower array targeting the energy range above 100 PeV.

  1. First modulation of high-frequency polar mesospheric summer echoes by radio heating of the ionosphere

    Science.gov (United States)

    Senior, A.; Mahmoudian, A.; Pinedo, H.; La Hoz, C.; Rietveld, M. T.; Scales, W. A.; Kosch, M. J.

    2014-08-01

    The first high-frequency (HF, 8 MHz) observations of the modulation of polar mesospheric summer echoes (PMSE) by artificial radio heating of the ionosphere are presented and compared to observations at 224 MHz and model predictions. The experiments were performed at the European Incoherent Scatter facility in northern Norway. It is shown that model results are in qualitative and partial quantitative agreement with the observations, supporting the prediction that with certain ranges of ice particle radii and concentration, PMSE at HF radar wavelengths can be enhanced by heating due to the dominance of dust charging over plasma diffusion.

  2. Variations of Saturn's radio rotation period measured at kilometer wavelengths

    Science.gov (United States)

    Galopeau, Patrick H. M.; Lecacheux, Alain

    2000-06-01

    The Unified Radio and Plasma Wave (URAP) experiment on the interplanetary spacecraft Ulysses is able to detect the Saturnian kilometric radiation (SKR) thanks to the high sensitivity of the receiver and in spite of the remoteness of the planet (8-13 AU). Our knowledge about Saturn comes essentially from the observations by the two Voyager spacecraft. Ulysses allows us to reassess the main properties of the SKR as they had been observed by Voyager 1 and 2: average flux density, spectrum, periodicity, and polarization. A striking difference between the results obtained from Voyager and those obtained from Ulysses is the periodicity of the radio emission linked to the planetary rotation (10 hours 39 min 24 s): The period deduced from Ulysses' observations is not constant and may differ by 1% from that of Voyager. The northern and southern sources of SKR are distributed along magnetic field lines which are fixed in local time. We interpret the source location by a Kelvin-Helmholtz instability developing on the flanks of Saturn's magnetopause, in the morningside. This instability could be at the origin of the acceleration of the particles responsible for the radio emission. Because of the solar wind fluctuations, the position of the magnetopause and the magnetohydrodynamic flow around it are modified so that the zone of Kelvin-Helmholtz instability slowly moves, implying a drift of the radio sources in local time. We examine and discuss the possibility for this drift to be the cause of the variations observed for the SKR period.

  3. Polarization measurements of proton capture gamma rays

    NARCIS (Netherlands)

    Suffert, M.; Endt, P.M.; Hoogenboom, A.M.

    1959-01-01

    The linear polarization has been measured of eight different gamma rays of widely differing energies (Eγ = 0.8 - 8.0 MeV) emitted at resonances in the 24Mg(p, γ)25Al, 30Si(p, γ)31P, and 32S(p, γ)33Cl reactions. The gamma rays emitted at 90° to the proton beam were Compton scattered in a 2″ NaI scint

  4. Montblanc: GPU accelerated Radio Interferometer Measurement Equations in support of Bayesian Inference for Radio Observations

    CERN Document Server

    Perkins, Simon; Zwart, Jonathan; Natarajan, Iniyan; Smirnov, Oleg

    2015-01-01

    We present Montblanc, a GPU implementation of the Radio interferometer measurement equation (RIME) in support of the Bayesian inference for radio observations (BIRO) technique. BIRO uses Bayesian inference to select sky models that best match the visibilities observed by a radio interferometer. To accomplish this, BIRO evaluates the RIME multiple times, varying sky model parameters to produce multiple model visibilities. Chi-squared values computed from the model and observed visibilities are used as likelihood values to drive the Bayesian sampling process and select the best sky model. As most of the elements of the RIME and chi-squared calculation are independent of one another, they are highly amenable to parallel computation. Additionally, Montblanc caters for iterative RIME evaluation to produce multiple chi-squared values. Only modified model parameters are transferred to the GPU between each iteration. We implemented Montblanc as a Python package based upon NVIDIA's CUDA architecture. As such, it is ea...

  5. Theoretical Models for Producing Circularly Polarized Radiation in Extragalactic Radio Sources

    CERN Document Server

    Wardle, J F C; Wardle, John F. C.; Homan, Daniel C.

    2003-01-01

    We discuss the production of circular polarization in compact radio sources both by the intrinsic mechanism and by Faraday conversion. We pay particular attention to the magnetic field structure, considering partially ordered fiel ds and Laing sheets, and distinguishing between uniform and unidirectional fields. (The latter can be constrained b y flux conservation arguments.) In most cases, Faraday conversion is the more important mechanism. Conversion opera tes on Stokes U, which can be generated by internal Faraday rotation, or by magnetic field fluctuations, which can therefore produce circular polarization even in a pure pair plasma. We also show that the spectrum of circular pola rization in an inhomogeneous jet can be quite different from that in a uniform source, being flat or even inverted.

  6. Air shower measurements with the LOPES radio antenna array

    Energy Technology Data Exchange (ETDEWEB)

    Haungs, A. [Institut fuer Kernphysik, Forschungszentrum Karlsruhe (Germany)], E-mail: andreas.haungs@ik.fzk.de; Apel, W.D. [Institut fuer Kernphysik, Forschungszentrum Karlsruhe (Germany); Arteaga, J.C. [Institut fuer Experimentelle Kernphysik, Universitaet Karlsruhe (Germany); Asch, T. [Inst. Prozessdatenverarbeitung und Elektronik, Forschungszentrum Karlsruhe (Germany); Auffenberg, J. [Fachbereich Physik, Universitaet Wuppertal (Germany); Badea, F. [Institut fuer Kernphysik, Forschungszentrum Karlsruhe (Germany); Baehren, L. [Department of Astrophysics, Radboud University Nijmegen (Netherlands); Bekk, K. [Institut fuer Kernphysik, Forschungszentrum Karlsruhe (Germany); Bertaina, M. [Dipartimento di Fisica Generale dell' Universita, Torino (Italy); Biermann, P.L. [Max-Planck-Institut fuer Radioastronomie, Bonn (Germany); Bluemer, J. [Institut fuer Kernphysik, Forschungszentrum Karlsruhe (Germany); Institut fuer Experimentelle Kernphysik, Universitaet Karlsruhe (Germany); Bozdog, H. [Institut fuer Kernphysik, Forschungszentrum Karlsruhe (Germany); Brancus, I.M. [National Institute of Physics and Nuclear Engineering, Bucharest (Romania); Brueggemann, M.; Buchholz, P. [Fachbereich Physik, Universitaet Siegen (Germany); Buitink, S. [Department of Astrophysics, Radboud University Nijmegen (Netherlands); Cantoni, E. [Dipartimento di Fisica Generale dell' Universita, Torino (Italy); Istituto di Fisica dello Spazio Interplanetario, INAF, Torino (Italy); Chiavassa, A. [Dipartimento di Fisica Generale dell' Universita, Torino (Italy); Cossavella, F. [Institut fuer Experimentelle Kernphysik, Universitaet Karlsruhe (Germany); Daumiller, K. [Institut fuer Kernphysik, Forschungszentrum Karlsruhe (Germany)] (and others)

    2009-06-01

    LOPES is set up at the location of the KASCADE-Grande extensive air shower experiment in Karlsruhe, Germany and aims to measure and investigate radio pulses from extensive air showers. Since radio waves suffer very little attenuation, radio measurements allow the detection of very distant or highly inclined showers. These waves can be recorded day and night, and provide a bolometric measure of the leptonic shower component. LOPES is designed as a digital radio interferometer using high bandwidths and fast data processing and profits from the reconstructed air shower observables of KASCADE-Grande. The LOPES antennas are absolutely amplitude calibrated allowing to reconstruct the electric field strength which can be compared with predictions from detailed Monte-Carlo simulations. We report about the analysis of correlations present in the radio signals measured by the LOPES 30 antenna array. Additionally, LOPES operates antennas of a different type (LOPES{sup STAR}) which are optimized for an application at the Pierre Auger Observatory. Status, recent results of the data analysis and further perspectives of LOPES and the possible large scale application of this new detection technique are discussed.

  7. A study of broadband Faraday rotation and polarization behaviour over 1.3--10 GHz in 36 discrete radio sources

    CERN Document Server

    Anderson, C S; Feain, I J

    2016-01-01

    We present a broadband polarization analysis of 36 discrete polarized radio sources over a very broad, densely-sampled frequency band. Our sample was selected on the basis of polarization behaviour apparent in narrowband archival data at 1.4 GHz: half the sample show complicated frequency-dependent polarization behaviour (i.e. Faraday complexity) at these frequencies, while half show comparatively simple behaviour (i.e. they appear Faraday simple). We re-observed the sample using the Australia Telescope Compact Array (ATCA) in full polarization, with 6 GHz of densely sampled frequency coverage spanning 1.3 to 10 GHz. We have devised a general polarization modelling technique that allows us to identify multiple polarized emission components in a source, and to characterize their properties. We detect Faraday complex behaviour in almost every source in our sample. Several sources exhibit particularly remarkable polarization behaviour. By comparing our new and archival data, we have identified temporal variabili...

  8. Indoor radio channel modeling and mitigation of fading effects using linear and circular polarized antennas in combination for smart home system at 868 MHz

    Science.gov (United States)

    Wunderlich, S.; Welpot, M.; Gaspard, I.

    2014-11-01

    The markets for smart home products and services are expected to grow over the next years, driven by the increasing demands of homeowners considering energy monitoring, management, environmental controls and security. Many of these new systems will be installed in existing homes and offices and therefore using radio based systems for cost reduction. A drawback of radio based systems in indoor environments are fading effects which lead to a high variance of the received signal strength and thereby to a difficult predictability of the encountered path loss of the various communication links. For that reason it is necessary to derive a statistical path loss model which can be used to plan a reliable and cost effective radio network. This paper presents the results of a measurement campaign, which was performed in six buildings to deduce realistic radio channel models for a high variety of indoor radio propagation scenarios in the short range devices (SRD) band at 868 MHz. Furthermore, a potential concept to reduce the variance of the received signal strength using a circular polarized (CP) patch antenna in combination with a linear polarized antenna in an one-to-one communication link is presented.

  9. Polar nephelometer for sea truth measurements

    Energy Technology Data Exchange (ETDEWEB)

    Haltrin, V.I. [Naval Research Lab., Stennis Space Center, MS (United States); Lee, M.E.; Martynov, O.V. [Optical Oceanography Lab., Crimea (United Kingdom)

    1996-11-01

    The SeaWiFS Pre-launch Science Working Group pointed out the importance of in situ measurements of the volume scattering function for sea water. Thus a need has arisen for the development of a new polar nephelometer which can support such measurements, because presently used instruments are not adequate to this task. We propose here a new approach to measure the volume scattering function, in which a light source and photodetector are fixed and angle deviation is implemented via rotation of a special periscope prism with three reflecting facets. The shape of this special periscope prism together with precisely adjusted dimensions allow the detection of the scattered radiance practically over the full angular range including the case of direct beam attenuation measurement. This approach gives us the opportunity to develop a fast and compact polar nephelometer, capable of measuring the volume scattering function over the full angular range using modem systems of data acquisition, managing and processing. 11 refs., 2 figs.

  10. When less is more: Are radio galaxies below the Fanaroff-Riley break more polarized on parsec scales ?

    CERN Document Server

    Kharb, P; Gabuzda, D C

    2005-01-01

    We present images showing the first detections of polarization on parsec scales in the nuclei of four Fanaroff-Riley type I (low-luminosity) radio galaxies. Observations with Very Long Baseline Interferometry at \\lambda 3.6cm reveal the presence of ordered magnetic fields within ~1650 Schwarzchild radii of the putative central supermassive black hole. The relatively high fractional polarization in the pc-scale jets of these galaxies is consistent with the standard scheme unifying low-luminosity radio galaxies with BL Lac objects. This result also suggests that these radio galaxies lack the obscuring tori that apparently depolarize the nuclear emission in the more powerful FRII radio galaxies, and that their supermassive blackholes are poorly fed and/or inefficient radiators.

  11. How could quark polarization be measured

    CERN Document Server

    Efremov, A V

    2000-01-01

    The perspectives of two new nonstandard methods of transversal quark polarization measurement are considered: the jet handedness and the so-called "Collins effect" due to a spin dependent T-odd fragmentation function responsible for the left-right asymmetry in fragmenting of transversally polarized quarks. Recent experimental indications in favor of these effects are observed: 1. The correlation of the T-odd one-particle fragmentation functions found by DELPHI in Z to 2-jet decay. Integrated over the fraction of longitudinal and transversal momenta, this correlation is of 1.6% order, which means order of 13% for the analyzing power. 2. A rather large ( approximately=10%) handedness transversal to the production plane observed in the diffractive production of ( pi /sup -/ pi /sup +/ pi /sup -/) triples from nuclei by the 40 GeV/c pi /sup -/-beam. It shows a clear dynamic origin and resembles the single spin asymmetry behavior. All this makes us hope to use these effects in polarized DIS experiments for transve...

  12. The New Horizons Bistatic Radio Science Experiment to Measure Pluto's Surface Properties

    Science.gov (United States)

    Linscott, I.; Hinson, D. P.; Tyler, G. L.; Vincent, M.

    2014-12-01

    The New Horizons (NH) payload includes a Radio Science Experiment (REX) for principally occultation and radiometric measurement of Pluto and Charon during the flyby in July 2015. The REX subsystem is contained, together with the NH X-Band radio, in the Integrated Electronics Module (IEM) in the New Horizons spacecraft. REX samples and records in two polarizations both total RF power in a 4.5 MHz bandwidth, and radio signal waveforms in a narrow, 1.25 kHz band. During the encounter, and at closest approach to Pluto, the spacecraft's high gain antenna (HGA) will scan Pluto's equatorial latitudes, intercepting the specular zone, a region near Pluto's limb that geometrically favors reflection from the earth's direction. At the same time, a powerful 80 kW uplink beacon will have been transmitted from earth by the DSN to arrive at Pluto during spacecraft closest approach. Reflection from the specular zone is expected to be sufficiently strong to observe the bistatic uplink in the REX narrowband record. Measurements in both polarizations will then be combined to yield surface reflectivity, roughness and limits on the dielectric constant in the specular zone.

  13. Measurement of radio emission from extensive air showers

    OpenAIRE

    Hoerandel, Joerg R.

    2009-01-01

    A new promising development in astroparticle physics is to measure the radio emission from extensive air showers. The particles in the cascade emit synchrotron radiation (30 - 90 MHz) which is detected with arrays of dipole antennas. Recent experimental efforts are discussed.

  14. Measurements of radio frequent cavity volt ages by X-ray spectrum measurements

    Directory of Open Access Journals (Sweden)

    Toprek Dragan

    2005-01-01

    Full Text Available This paper deals with X-ray spectrum measurement as a method for the measurement of radio frequent cavity voltage and the theory of X-ray spectrum calculation. Experimental results at 72 MHz for three different values of the radio frequent power of ACCEL K250 super conducting cyclotron are being presented.

  15. Radio occultation measurements of Pluto's neutral atmosphere with New Horizons

    Science.gov (United States)

    Hinson, D. P.; Linscott, I. R.; Young, L. A.; Tyler, G. L.; Stern, S. A.; Beyer, R. A.; Bird, M. K.; Ennico, K.; Gladstone, G. R.; Olkin, C. B.; Pätzold, M.; Schenk, P. M.; Strobel, D. F.; Summers, M. E.; Weaver, H. A.; Woods, W. W.

    2017-07-01

    On 14 July 2015 New Horizons performed a radio occultation (RO) that sounded Pluto's atmosphere down to the surface. The sensitivity of the measurements was enhanced by a unique configuration of ground equipment and spacecraft instrumentation. Signals were transmitted simultaneously by four antennas of the NASA Deep Space Network, each radiating 20 kW at a wavelength of 4.2 cm. The polarization was right circular for one pair of signals and left circular for the other pair. New Horizons received the four signals and separated them by polarization for processing by two independent receivers, each referenced to a different ultra-stable oscillator. The two data streams were digitized, filtered, and stored on the spacecraft for later transmission to Earth. The results reported here are the first to utilize the complete set of observations. We calibrated each signal to remove effects not associated with Pluto's atmosphere, including the limb diffraction pattern. We then applied a specialized method of analysis to retrieve profiles of number density, pressure, and temperature from the combined phase measurements. Occultation entry sounded the atmosphere at sunset at 193.5°E, 17.0°S - on the southeast margin of an ice-filled basin known informally as Sputnik Planitia (SP); occultation exit occurred at sunrise at 15.7°E, 15.1°N - near the center of the Charon-facing hemisphere. Above 1215 km radius (∼25 km altitude) there is no discernible difference between the measurements at entry and exit, and the RO profiles are consistent with results derived from ground-based stellar occultation measurements. At lower altitudes the RO measurements reveal horizontal variations in atmospheric structure that had not been observed previously, and they are the first to reach the ground. The entry profile has a strong temperature inversion that ends 3.5 km above the surface, and the temperature in the cold boundary layer beneath the inversion is nearly constant, 38.9 ± 2.1 K, and

  16. Measuring the continuum linear polarization with ESPaDOnS

    CERN Document Server

    Pereyra, A; Martioli, E

    2014-01-01

    Our goal is to test the feasibility to obtain accurate measurements of the continuum linear polarization from high-resolution spectra using the spectropolarimetric mode of ESPaDOnS. We used the new pipeline OPERA to reduce recent and archived ESPaDOnS data. A couple of standard polarization stars and several science objects were tested. Synthetic broad-band polarization was computed from the ESPaDOnS continuum linear polarization spectra and compared with published values to quantify the accuracy of the instrument. The continuum linear polarization measured by ESPaDOnS is consistent with the broad-band polarimetry measurements available in the literature. The polarization degree accuracy is better than 0.2% considering the full sample. The accuracy in polarization position angle using the most polarized objects is better than 5deg. Our results suggest that measurements of the continuum linear polarization using ESPaDOnS are viable.

  17. The Tunka Radio Extension (Tunka-Rex): Radio Measurements of Cosmic Rays in Siberia (PISA 2015)

    CERN Document Server

    Schröder, F G; Budnev, N M; Gress, O A; Haungs, A; Hiller, R; Huege, T; Kazarina, Y; Kleifges, M; Konstantinov, E N; Korosteleva, E E; Kostunin, D; Krömer, O; Kuzmichev, L A; Lubsandorzhiev, N; Mirgazov, R R; Monkhoev, R; Pakhorukov, A; Pankov, L; Prosin, V V; Rubtsov, G I; Wischnewski, R; Zagorodnikov, A

    2015-01-01

    The Tunka observatory is located close to Lake Baikal in Siberia, Russia. Its main detector, Tunka-133, is an array of photomultipliers measuring Cherenkov light of air showers initiated by cosmic rays in the energy range of approximately $10^{16}-10^{18}\\,$eV. In the last years, several extensions have been built at the Tunka site, e.g., a scintillator array named Tunka-Grande, a sophisticated air-Cherenkov-detector prototype named HiSCORE, and the radio extension Tunka-Rex. Tunka-Rex started operation in October 2012 and currently features 44 antennas distributed over an area of about $3\\,$km$^2$, which measure the radio emission of the same air showers detected by Tunka-133 and Tunka-Grande. Tunka-Rex is a technological demonstrator that the radio technique can provide an economic extension of existing air-shower arrays. The main scientific goal is the cross-calibration with the air-Cherenkov measurements. By this cross-calibration, the precision for the reconstruction of the energy and mass of the primary...

  18. When less is more: Are radio galaxies below the Fanaroff-Riley break more polarized on parsec scales ?

    OpenAIRE

    Kharb, P.; Shastri, P; Gabuzda, D. C.

    2005-01-01

    We present images showing the first detections of polarization on parsec scales in the nuclei of four Fanaroff-Riley type I (low-luminosity) radio galaxies. Observations with Very Long Baseline Interferometry at \\lambda 3.6cm reveal the presence of ordered magnetic fields within ~1650 Schwarzchild radii of the putative central supermassive black hole. The relatively high fractional polarization in the pc-scale jets of these galaxies is consistent with the standard scheme unifying low-luminosi...

  19. Measuring the radio emission of cosmic ray air showers with LOPES

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, F.G., E-mail: Frank.Schroeder@kit.ed [Institut fuer Kernphysik, Karlsruhe Institute of Technology (KIT) (Germany); Apel, W.D. [Institut fuer Kernphysik, Karlsruhe Institute of Technology (KIT) (Germany); Arteaga, J.C. [Institut fuer Experimentelle Kernphysik, Karlsruhe Institute of Technology (KIT) (Germany); Asch, T. [Institut fuer Prozessdatenverarbeitung und Elektronik, Karlsruhe Institute of Technology (KIT) (Germany); Badea, F. [Institut fuer Kernphysik, Karlsruhe Institute of Technology (KIT) (Germany); Baehren, L. [Department of Astrophysics, Radboud University Nijmegen (Netherlands); Bekk, K. [Institut fuer Kernphysik, Karlsruhe Institute of Technology (KIT) (Germany); Bertaina, M. [Dipartimento di Fisica Generale dell' Universita Torino (Italy); Biermann, P.L. [Max-Planck-Institut fuer Radioastronomie Bonn (Germany); Bluemer, J. [Institut fuer Kernphysik, Karlsruhe Institute of Technology (KIT) (Germany); Institut fuer Experimentelle Kernphysik, Karlsruhe Institute of Technology (KIT) (Germany); Bozdog, H. [Institut fuer Kernphysik, Karlsruhe Institute of Technology (KIT) (Germany); Brancus, I.M. [National Institute of Physics and Nuclear Engineering, Bucharest (Romania); Brueggemann, M.; Buchholz, P. [Fachbereich Physik, Universitaet Siegen (Germany); Buitink, S. [Department of Astrophysics, Radboud University Nijmegen (Netherlands); Cantoni, E. [Dipartimento di Fisica Generale dell' Universita Torino (Italy); Istituto di Fisica dello Spazio Interplanetario, INAF Torino (Italy); Chiavassa, A. [Dipartimento di Fisica Generale dell' Universita Torino (Italy); Cossavella, F. [Institut fuer Experimentelle Kernphysik, Karlsruhe Institute of Technology (KIT) (Germany); Daumiller, K. [Institut fuer Kernphysik, Karlsruhe Institute of Technology (KIT) (Germany); Souza, V. de [Institut fuer Experimentelle Kernphysik, Karlsruhe Institute of Technology (KIT) (Germany)

    2010-05-21

    When ultra high energy cosmic rays hit the atmosphere, they produce a shower of millions of secondary particles. Thereby the charged particles in the shower emit a radio pulse whilst deflected in the Earth's magnetic field. LOPES is a digital antenna array measuring these radio pulses in the frequency range from 40 to 80 MHz. It is located at the site of and triggered by the air shower experiment KASCADE-Grande at Karlsruhe Institute of Technology (KIT), Germany. In its present configuration, it consists of 15 east-west-polarized and 15 north-south-polarized, absolutely calibrated short dipole antennas, as well as 10 LPDAs (with two channels each). Furthermore, it serves as a test bench for technological developments, like new antenna types or a radio-based self-triggering (LOPES{sup STAR}). To achieve a good angular reconstruction and to digitally form a beam into the arrival direction of the shower, it has a precise time calibration.

  20. Rotation Measure Synthesis of Galactic Polarized Emission with the DRAO 26-m Telescope

    CERN Document Server

    Wolleben, M; Hovey, G J; Messing, R; Davison, O S; House, N L; Somaratne, K H M S; Tashev, I

    2010-01-01

    Radio polarimetry at decimetre wavelengths is the principal source of information on the Galactic magnetic field. The diffuse polarized emission is strongly influenced by Faraday rotation in the magneto-ionic medium and rotation measure is the prime quantity of interest, implying that all Stokes parameters must be measured over wide frequency bands with many frequency channels. The DRAO 26-m Telescope has been equipped with a wideband feed, a polarization transducer to deliver both hands of circular polarization, and a receiver, all operating from 1277 to 1762 MHz. Half-power beamwidth is between 40 and 30 arcminutes. A digital FPGA spectrometer, based on commercially available components, produces all Stokes parameters in 2048 frequency channels over a 485-MHz bandwidth. Signals are digitized to 8 bits and a Fast Fourier Transform is applied to each data stream. Stokes parameters are then generated in each frequency channel. This instrument is in use at DRAO for a Northern sky polarization survey. Observatio...

  1. Polarization factor measurements of flat crystals using synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Wohrer, K.; Touati, A.; Chetioui, A.; Rozet, J.P.; Chevallier, P.; Wang, J.X.; Bouisset, P.

    1989-01-01

    A method for measuring polarization factors of flat crystals, using a highly polarized beam source provided by synchrotron radiation, is presented. Application to the test of a graphite mosaic crystal, performed at the LURE-DCI facility in Orsay (France), is reported. Results concerning polarization factors at different energies are discussed in connection with measured crystal reflectivities.

  2. A measurement of τ polarization at LEP

    Science.gov (United States)

    Acciarri, M.; Adam, A.; Adriani, O.; Aguilar-Benitez, M.; Ahlen, S.; Alcaraz, J.; Aloisio, A.; Alverson, G.; Alviggi, M. G.; Ambrosi, G.; An, Q.; Anderhub, H.; Anderson, A. L.; Andreev, V. P.; Angelescu, T.; Antonov, L.; Antreasyan, D.; Alkhazov, G.; Arce, P.; Arefiev, A.; Azemoon, T.; Aziz, T.; Baba, P. V. K. S.; Bagnaia, P.; Bakken, J. A.; Baksay, L.; Ball, R. C.; Banerjee, S.; Banicz, K.; Barillère, R.; Barone, L.; Baschirotto, A.; Basile, M.; Battiston, R.; Bay, A.; Becattini, F.; Becker, U.; Behner, F.; Bencze, Gy. L.; Berdugo, J.; Berges, P.; Bertucci, B.; Betev, B. L.; Biasini, M.; Biland, A.; Bilei, G. M.; Bizzarri, R.; Blaising, J. J.; Bobbink, G. J.; Bock, R.; Böhm, A.; Borgia, B.; Boucham, A.; Bourilkov, D.; Bourquin, M.; Boutigny, D.; Bouwens, B.; Brambilla, E.; Branson, J. G.; Brigljevic, V.; Brock, I. C.; Brooks, M.; Bujak, A.; Burger, J. D.; Burger, W. J.; Burgos, C.; Busenitz, J.; Buytenhuijs, A.; Bykov, A.; Cai, X. D.; Capell, M.; Romeo, G. Cara; Caria, M.; Carlino, G.; Cartacci, A. M.; Casaus, J.; Castello, R.; Cavallo, N.; Cerrada, M.; Cesaroni, F.; Chamizo, M.; Chang, Y. H.; Chaturvedi, U. K.; Chemarin, M.; Chen, A.; Chen, G.; Chen, G.; Chen, G. M.; Chen, H. F.; Chen, H. S.; Chen, M.; Chiefari, G.; Chien, C. Y.; Choi, M. T.; Chung, S.; Cifarelli, L.; Cindolo, F.; Civinini, C.; Clare, I.; Clare, R.; Coan, T. E.; Cohn, H. O.; Coignet, G.; Colino, N.; Costantini, S.; Cotorobai, F.; de la Cruz, B.; Cui, X. T.; Cui, X. Y.; Dai, T. S.; D'Alessandro, R.; de Asmundis, R.; Degré, A.; Deiters, K.; Dénes, E.; Denes, P.; DeNotaristefani, F.; DiBitonto, D.; Diemoz, M.; Dimitrov, H. R.; Dionisi, C.; Dittmar, M.; Djambazov, L.; Dorne, I.; Dova, M. T.; Drago, E.; Duchesneau, D.; Duhem, F.; Duinker, P.; Duran, I.; Dutta, S.; Easo, S.; El Mamouni, H.; Engler, A.; Eppling, F. J.; Erné, F. C.; Extermann, P.; Fabbretti, R.; Fabre, M.; Falciano, S.; Favara, A.; Fay, J.; Felcini, M.; Ferguson, T.; Fernandez, D.; Fernandez, G.; Ferroni, F.; Fesefeldt, H.; Fiandrini, E.; Field, J. H.; Filthaut, F.; Fisher, P. H.; Forconi, G.; Fredj, L.; Freudenreich, K.; Gailloud, M.; Galaktionov, Yu.; Gallo, E.; Ganguli, S. N.; Garcia-Abia, P.; Gentile, S.; Gerald, J.; Gheordanescu, N.; Giagu, S.; Goldfarb, S.; Goldstein, J.; Gong, Z. F.; Gonzalez, E.; Gougas, A.; Goujon, D.; Gratta, G.; Gruenewald, M. W.; Gu, C.; Guanziroli, M.; Gupta, V. K.; Gurtu, A.; Gustafson, H. R.; Gutay, L. J.; Hasan, A.; Hauschildt, D.; He, J. T.; Hebbeker, T.; Hebert, M.; Hervé, A.; Hilgers, K.; Hofer, H.; Hoorani, H.; Hou, S. R.; Hu, G.; Ille, B.; Ilyas, M. M.; Innocente, V.; Janssen, H.; Jin, B. N.; Jones, L. W.; de Jong, P.; Josa-Mutuberria, I.; Kasser, A.; Khan, R. A.; Kamyshkov, Yu.; Kapinos, P.; Kapustinsky, J. S.; Karyotakis, Y.; Kaur, M.; Khokhar, S.; Kienzle-Focacci, M. N.; Kim, D.; Kim, J. K.; Kim, S. C.; Kim, Y. G.; Kinnison, W. W.; Kirkby, A.; Kirkby, D.; Kirsch, S.; Kittel, W.; Klimentov, A.; König, A. C.; Koffeman, E.; Kornadt, O.; Koutsenko, V.; Koulbardis, A.; Kraemer, R. W.; Kramer, T.; Krastev, V. R.; Krenz, W.; Kuijten, H.; Kumar, K. S.; Kunin, A.; Ladron de Guevara, P.; Landi, G.; Lanske, D.; Lanzano, S.; Lebedev, A.; Lebrun, P.; Lecomte, P.; Lecoq, P.; Le Coultre, P.; Lee, D. M.; Lee, J. S.; Lee, K. Y.; Leedom, I.; Leggett, C.; Le Goff, J. M.; Leiste, R.; Lenti, M.; Leonardi, E.; Levtchenko, P.; Li, C.; Lieb, E.; Lin, W. T.; Linde, F. L.; Lindemann, B.; Lista, L.; Liu, Y.; Lohmann, W.; Longo, E.; Lu, W.; Lu, Y. S.; Lubbers, J. M.; Lübelsmeyer, K.; Luci, C.; Luckey, D.; Ludovici, L.; Luminari, L.; Lustermann, W.; Ma, W. G.; MacDermott, M.; Maity, M.; Malgeri, L.; Malik, R.; Malinin, A.; Maña, C.; Mangla, S.; Maolinbay, M.; Marchesini, P.; Marin, A.; Martin, J. P.; Marzano, F.; Massaro, G. G. G.; Mazumdar, K.; McBride, P.; McMahon, T.; McNally, D.; Mele, S.; Merk, M.; Merola, L.; Meschini, M.; Metzger, W. J.; Mi, Y.; Mihul, A.; Mills, G. B.; Mir, Y.; Mirabelli, G.; Mnich, J.; Möller, M.; Monaco, V.; Monteleoni, B.; Morand, R.; Morganti, S.; Moulai, N. E.; Mount, R.; Müller, S.; Nagy, E.; Napolitano, M.; Nessi-Tedaldi, F.; Newman, H.; Niaz, M. A.; Nippe, A.; Nowak, H.; Organtini, G.; Pandoulas, D.; Paoletti, S.; Paolucci, P.; Pascale, G.; Passaleva, G.; Patricelli, S.; Paul, T.; Pauluzzi, M.; Paus, C.; Pauss, F.; Pei, Y. J.; Pensotti, S.; Perret-Gallix, D.; Pevsner, A.; Piccolo, D.; Pieri, M.; Pinto, J. C.; Piroué, P. A.; Pistolesi, E.; Plasil, F.; Plyaskin, V.; Pohl, M.; Pojidaev, V.; Postema, H.; Produit, N.; Qian, J. M.; Qureshi, K. N.; Raghavan, R.; Rahal-Callot, G.; Rancoita, P. G.; Rattaggi, M.; Raven, G.; Razis, P.; Read, K.; Redaelli, M.; Ren, D.; Ren, Z.; Rescigno, M.; Reucroft, S.; Ricker, A.; Riemann, S.; Riemers, B. C.; Riles, K.; Rind, O.; Rizvi, H. A.; Ro, S.; Robohm, A.; Rodriguez, F. J.; Roe, B. P.; Röhner, M.; Röhner, S.; Romero, L.; Rosier-Lees, S.; Rosmalen, R.; Rosselet, Ph.; van Rossum, W.; Roth, S.; Rubbia, A.; Rubio, J. A.; Rykaczewski, H.; Salicio, J.; Sanchez, E.; Sanders, G. S.; Santocchia, A.; Sarakinos, M. E.; Sarkar, S.; Sartorelli, G.; Sassowsky, M.; Sauvage, G.; Schäfer, C.; Schegelsky, V.; Schmitz, D.; Schmitz, P.; Schneegans, M.; Scholz, N.; Schopper, H.; Schotanus, D. J.; Shotkin, S.; Schreiber, H. J.; Shukla, J.; Schulte, R.; Schultze, K.; Schwenke, J.; Schwering, G.; Sciacca, C.; Scott, I.; Sehgal, R.; Seiler, P. G.; Sens, J. C.; Servoli, L.; Sheer, I.; Shevchenko, S.; Shi, X. R.; Shumilov, E.; Shoutko, V.; Son, D.; Sopczak, A.; Soulimov, V.; Spartiotis, C.; Spickermann, T.; Spillantini, P.; Steuer, M.; Stickland, D. P.; Sticozzi, F.; Stone, H.; Strauch, K.; Sudhakar, K.; Sultanov, G.; Sun, L. Z.; Susinno, G. F.; Suter, H.; Swain, J. D.; Syed, A. A.; Tang, X. W.; Taylor, L.; Timellini, R.; Ting, Samuel C. C.; Toker, O.; Tonutti, M.; Tonwar, S. C.; Tóth, J.; Trowitzsch, G.; Tsaregorodtsev, A.; Tsipolitis, G.; Tully, C.; Ulbricht, J.; Urbán, L.; Uwer, U.; Valente, E.; Van de Walle, R. T.; Vetlitsky, I.; Viertel, G.; Vikas, P.; Vikas, U.; Vivargent, M.; Vogel, H.; Vogt, H.; Vorobiev, I.; Vorobyov, A. A.; Vorobyov, An. A.; Vuilleumier, L.; Wadhwa, M.; Wallraff, W.; Wang, J. C.; Wang, X. L.; Wang, Y. F.; Wang, Z. M.; Weber, A.; Weber, J.; Weill, R.; Willmott, C.; Wittgenstein, F.; Wright, D.; Wu, S. X.; Wynhoff, S.; Xu, Z. Z.; Yang, B. Z.; Yang, C. G.; Yang, G.; Yao, X. Y.; Ye, C. H.; Ye, J. B.; Ye, Q.; Yeh, S. C.; You, J. M.; Yunus, N.; Yzerman, M.; Zaccardelli, C.; Zemp, P.; Zeng, M.; Zeng, Y.; Zhang, D. H.; Zhang, Z. P.; Zhou, B.; Zhou, G. J.; Zhou, J. F.; Zhu, R. Y.; Zichichi, A.; van der Zwaan, B. C. C.; L3 Collaboration

    1994-12-01

    With a data sample of 86 000 Z → τ +τ -(γ) events collected in 1990 through 1993 we have measured the polarization of τ-leptons as a function of the production polar angle using the following 1-prong τ decay modes: τ -→ e-overlinevev τ, τ -→π - (K -)v τ, τ -→ϱ -v τand τ -→a 1-v τ. We obtain for the ratio vector to axial-vector weak neutral couplings for electrons gVe/ gAe=0.0791±0.0099(stat)±0.0025 (syst) and taus gVτ/ gAτ=0.0752±0.0063 (stat)±0.0045 (syst) consistent with the hypothesis of e - τ universality. Assuming universality of the e - τ neutral current we determine the effective electroweak mixing angle to be sin 2 θ effw = 0.2309 ± 0.0016.

  3. Measurement of Black Hole Mass Radio-Loud Quasars

    Indian Academy of Sciences (India)

    Cheng-Yue Su; Z.-F. Chen; R.-L. He; C.-H. Zhang; T.-T. Wang

    2011-03-01

    In this work, we construct a sample of 1585 radio-loud quasars to measure their black hole masses using broad emission lines. We compare our black hole masses with the virial black hole masses measured by Shen et al. (2010).We find that there is a large deviation between them if our black hole mass is measured from the CIV broad emission line. Whereas, if our black hole mass is measured from broad emission line of Mg II or H, both the values are consistent.

  4. Measurement of the polarization effects of an instrument using partially polarized light

    Science.gov (United States)

    Howell, B. J.

    1979-01-01

    Accuracy of a radiometer is adversely affected by scene polarization if the receiving optical system is sensitive to polarization. It is therefore necessary to specify and measure the sensitivity of the system to polarized light. The Mueller-Stokes matrix of an instrument may be determined experimentally and used to predict the effects of the instrument on any beam. The specification of a maximum polarization sensitivity stated in terms of the degree of polarization produced in an unpolarized beam can be experimentally verified even though an unpolarized beam is not available in the laboratory for direct measurement.

  5. Radio Frequency Radiation (RFR) Measurements in Operational Settings.

    Science.gov (United States)

    1984-12-01

    1NURAT0 OF -HSAG Deport No. 84-028CV111ARA USAF OCCUPATIONAL AND ENVIRONMENTAL HEALTH LABORATORY Brooks AFB, Texas 78235 RADIO FREQUENCY RADIATION (RFR...with a 60 Watt/cm3 peak power burnout rating. First attempts to use these early instruments (Model 8300). in the investigation of an alleged...an aside, Narda also makes several other probe series for measurements to as low as 300 Kiz. All Narda probes are susceptible to burnout when exposed

  6. A 3mm band dual polarization MMIC receiver for the 30-m Pico Veleta Radio Telescope

    Science.gov (United States)

    Serres, Patrice; Garnier, Olivier; Bortolotti, Yves; Navarro, Santiago; John, Dave; Pissard, Bruno; Navarrini, Alessandro; Schuster, Karl F.

    2012-09-01

    We present the design, construction and test results of a prototype MMIC receiver for the 3 mm band (84-116 GHz). The receiver cryogenic module consists of a single corrugated feed horn cascaded with an Ortho Mode Traducer (OMT) that splits the two incoming linear polarized signals in two independent single-mode rectangular waveguides. Low noise MMIC HEMT amplification modules, attached to the OMT WR10 waveguide outputs, amplify the signal of each polarization channel. Outside the dewar, each signal is filtered, down-converted, and further amplified to provide a final 8 GHz IF bandwidth across 4-12 GHz. The receiver was installed on the Pico Veleta 30 m telescope in August 2010 where it was used to perform spectral line surveys of astronomical sources. The measured receiver noise temperature was below 75 K with an average value of ~55 K for both polarization channels across 84-116 GHz.

  7. Radio-controlled boat for measuring water velocities and bathymetry

    Science.gov (United States)

    Vidmar, Andrej; Bezak, Nejc; Sečnik, Matej

    2016-04-01

    Radio-controlled boat named "Hi3" was designed and developed in order to facilitate water velocity and bathymetry measurements. The boat is equipped with the SonTek RiverSurveyor M9 instrument that is designed for measuring open channel hydraulics (discharge and bathymetry). Usually channel cross sections measurements are performed either from a bridge or from a vessel. However, these approaches have some limitations such as performing bathymetry measurements close to the hydropower plant turbine or downstream from a hydropower plant gate where bathymetry changes are often the most extreme. Therefore, the radio-controlled boat was designed, built and tested in order overcome these limitations. The boat is made from a surf board and two additional small balance support floats. Additional floats are used to improve stability in fast flowing and turbulent parts of rivers. The boat is powered by two electric motors, steering is achieved with changing the power applied to left and right motor. Furthermore, remotely controlled boat "Hi3" can be powered in two ways, either by a gasoline electric generator or by lithium batteries. Lithium batteries are lighter, quieter, but they operation time is shorter compared to an electrical generator. With the radio-controlled boat "Hi3" we can perform measurements in potentially dangerous areas such as under the lock gates at hydroelectric power plant or near the turbine outflow. Until today, the boat "Hi3" has driven more than 200 km in lakes and rivers, performing various water speed and bathymetry measurements. Moreover, in future development the boat "Hi3" will be upgraded in order to be able to perform measurements automatically. The future plans are to develop and implement the autopilot. With this approach the user will define the route that has to be driven by the boat and the boat will drive the pre-defined route automatically. This will be possible because of the very accurate differential GPS from the Sontek River

  8. RadioAstron space VLBI imaging of polarized radio emission in the high-redshift quasar 0642+449 at 1.6 GHz

    CERN Document Server

    Lobanov, A P; Bruni, G; Kovalev, Y Y; Anderson, J; Bach, U; Kraus, A; Zensus, J A; Lisakov, M M; Sokolovsky, K V; Voytsik, P A

    2015-01-01

    Polarization of radio emission in extragalactic jets at a sub-milliarcsecond angular resolution holds important clues for understanding the structure of the magnetic field in the inner regions of the jets and in close vicinity of the supermassive black holes in the centers of active galaxies. Space VLBI observations provide a unique tool for polarimetric imaging at a sub-milliarcsecond angular resolution and studying the properties of magnetic field in active galactic nuclei on scales of less than 10^4 gravitational radii. A space VLBI observation of high-redshift quasar TXS 0642+449 (OH 471), made at a wavelength of 18 cm (frequency of 1.6 GHz) as part of the Early Science Programme (ESP) of the RadioAstron} mission, is used here to test the polarimetric performance of the orbiting Space Radio Telescope (SRT) employed by the mission, to establish a methodology for making full Stokes polarimetry with space VLBI at 1.6 GHz, and to study the polarized emission in the target object on sub-milliarcsecond scales. ...

  9. Electron-ion temperature ratio estimations in the summer polar mesosphere when subject to HF radio wave heating

    Science.gov (United States)

    Pinedo, H.; La Hoz, C.; Havnes, O.; Rietveld, M.

    2014-10-01

    We have inferred the electron temperature enhancements above mesospheric altitudes under Polar Mesospheric Summer Echoes (PMSE) conditions when the ionosphere is exposed to artificial HF radio wave heating. The proposed method uses the dependence of the radar cross section on the electron-to-ion temperature ratio to infer the heating factor from incoherent scatter radar (ISR) power measurements above 90 km. Model heating temperatures match our ISR estimations between 90 and 130 km with 0.94 Pearson correlation index. The PMSE strength measured by the MORRO MST radar is about 50% weaker during the heater-on period when the modeled electron-to-ion mesospheric temperature is approximately 10 times greater than the unperturbed value. No PMSE weakening is found when the mesospheric temperature enhancement is by a factor of three or less. The PMSE weakening and its absence are consistent with the modeled mesospheric electron temperatures. This consistency supports to the proposed method for estimating mesospheric electron temperatures achieved by independent MST and ISR radar measurements.

  10. Accuracy of circular polarization as a measure of spin polarization in quantum dot qubits.

    Science.gov (United States)

    Pryor, C E; Flatté, M E

    2003-12-19

    A quantum dot spin light emitting diode provides a test of carrier spin injection into a qubit and a means for analyzing carrier spin injection and local spin polarization. Even with 100% spin-polarized carriers the emitted light may be only partially circularly polarized due to the geometry of the dot. We have calculated carrier polarization-dependent optical matrix elements for InAs/GaAs self-assembled quantum dots (SAQDs) for electron and hole spin injection into a range of quantum dot sizes and shapes, and for arbitrary emission directions. Calculations for typical SAQD geometries with emission along [110] show light that is only 5% circularly polarized for spin states that are 100% polarized along [110]. Measuring along the growth direction gives near unity conversion of spin to photon polarization and is the least sensitive to uncertainties in SAQD geometry.

  11. A compendium of AGN inclinations with corresponding UV/optical continuum polarization measurements

    Science.gov (United States)

    Marin, F.

    2014-06-01

    The anisotropic nature of active galactic nuclei (AGN) is thought to be responsible for the observational differences between type-1 (pole-on) and type-2 (edge-on) nearby Seyfert-like galaxies. In this picture, the detection of emission and/or absorption features is directly correlated to the inclination of the system. The AGN structure can be further probed by using the geometry-sensitive technique of polarimetry, yet the pairing between observed polarization and Seyfert type remains poorly examined. Based on archival data, I report here the first compilation of 53 estimated AGN inclinations matched with ultraviolet/optical continuum polarization measurements. Corrections, based on the polarization of broad emission lines, are applied to the sample of Seyfert-2 AGN to remove dilution by starburst light and derive information about the scattered continuum alone. The resulting compendium agrees with past empirical results, i.e. type-1 AGN show low polarization degrees (P ≤ 1 per cent) predominantly associated with a polarization position angle parallel to the projected radio axis of the system, while type-2 objects show stronger polarization percentages (P > 7 per cent) with perpendicular polarization angles. The transition between type-1 and type-2 inclination occurs between 45° and 60° without noticeable impact on P. The compendium is further used as a test to investigate the relevance of four AGN models. While an AGN model with fragmented regions matches observations better than uniform models, a structure with a failed dusty wind along the equator and disc-born, ionized, polar outflows is by far closer to observations. However, although the models correctly reproduce the observed dichotomy between parallel and perpendicular polarization, as well as correct polarization percentages at type-2 inclinations, further work is needed to account for some highly polarized type-1 AGN.

  12. The effect of raindrop vibration on the polarization characteristics of a radio echo

    Science.gov (United States)

    Gorelik, A. G.; Sterliadkin, V. V.

    1989-09-01

    The effect of the nonsphericity and vibration of raindrops on scattering microwave radiation and on the recorded signal spectrum is considered. The possibility of controlling the contribution of vibration to the recorded signal spectrum by the selection of the sounding radiation polarization angle is demonstrated. Prospects for increasing the accuracy of a radar measurement of the intensity of precipitation by obtaining data on the microstructure of rain are discussed.

  13. Measuring the Symmetry of Supernova Remnants in the Radio

    Science.gov (United States)

    Stafford, Jennifer; Lopez, Laura A.

    2017-01-01

    Nearly 300 supernova remnants (SNRs) are known in the MIlky Way galaxy, and they offer an important means to study the explosions and interactions of supernovae at sub-pc scales. In this poster, we present analysis of the morphology of Galactic SNRs at radio wavelengths. Specifically, we measure the symmetry of several tens of SNRs in 6- and 20-cm Very Large Array images using a multipole expansion technique, the power-ratio method. We explore how the SNRs' morphology changes as a function of their size and estimated dynamical ages, with the aim of probing how SNR shapes evolve with time.

  14. Experimental verification of long-term evolution radio transmissions over dual-polarization combined fiber and free-space optics optical infrastructures.

    Science.gov (United States)

    Bohata, J; Zvanovec, S; Pesek, P; Korinek, T; Mansour Abadi, M; Ghassemlooy, Z

    2016-03-10

    This paper describes the experimental verification of the utilization of long-term evolution radio over fiber (RoF) and radio over free space optics (RoFSO) systems using dual-polarization signals for cloud radio access network applications determining the specific utilization limits. A number of free space optics configurations are proposed and investigated under different atmospheric turbulence regimes in order to recommend the best setup configuration. We show that the performance of the proposed link, based on the combination of RoF and RoFSO for 64 QAM at 2.6 GHz, is more affected by the turbulence based on the measured difference error vector magnitude value of 5.5%. It is further demonstrated the proposed systems can offer higher noise immunity under particular scenarios with the signal-to-noise ratio reliability limit of 5 dB in the radio frequency domain for RoF and 19.3 dB in the optical domain for a combination of RoF and RoFSO links.

  15. Variable and polarized radio emission from the T6 brown dwarf WISEP J112254.73+255021.5

    CERN Document Server

    Williams, P K G; Berger, E

    2016-01-01

    Route & Wolszczan (2016) recently detected five radio bursts from the T6 dwarf WISEP J112254.73+255021.5 and used the timing of these events to propose that this object rotates with an ultra-short period of ~17.3 minutes. We conducted follow-up observations with the Very Large Array and Gemini-North but found no evidence for this periodicity. We do, however, observe variable, highly circularly polarized radio emission possibly with a period of 116 minutes, although our observation lasted only 162 minutes and so more data are needed to confirm it. Our proposed periodicity is typical of other radio-active ultracool dwarfs. The handedness of the circular polarization alternates with time and there is no evidence for any unpolarized emission component, the first time such a phenomenology has been observed in radio studies of very low-mass stars and brown dwarfs. We suggest that the object's magnetic dipole axis may be highly misaligned relative to its rotation axis.

  16. Measurement of ocular counterrolling /OCR/ by polarized light

    Science.gov (United States)

    Kenyon, R. V.; Lichtenberg, B. K.

    1982-01-01

    The assessment of the activation of the otolith gravitoinertial sensors in the vestibular system of the inner ear may be accomplished by observing the occular counterrolling (OCR) movements which rotate the eyes about the line of sight. A method is presented for the continuous measurement of OCR by means of polarized light, a system of polarizers, and a contact lens. A polarized hard contact lens is placed between two soft lenses before application to the eye, and the measured phase difference between the incident rotating polarized light and the reflected light from this lens provides readings uncontaminated by other eye movement modes.

  17. Polarization Invariants and Retrieval of Surface Parameters Using Polarization Measurements in Remote Sensing Applications

    CERN Document Server

    Shestopaloff, Yu K

    2012-01-01

    Using polarization measurements in remote sensing and optical studies allows retrieving more information. We consider relationship between the reflection coefficients of plane and rough surfaces for linearly polarized waves. Certain polarization properties of reflected waves and polarization invariants, in particular at incident angle of forty five degrees, allow finding amplitude and phase characteristics of reflected waves. Based on this study, we introduce methods for finding dielectric permittivity, temperature and geometrical characteristics of observed surfaces. Experimental results prove that these methods can be used for different practical purposes in technological and remote sensing applications, in a broad range of electromagnetic spectrum.

  18. Mesosphere Study by Wide-Field Twilight Polarization Measurements: First Results beyond the Polar Circle

    CERN Document Server

    Ugolnikov, Oleg S

    2015-01-01

    The paper contains the observations description and first results of mesosphere temperature and dust study based on twilight wide-field polarization analysis started in 2015 in Apatity, northern Russia (67.6 deg N, 33.4 deg E) with original all-sky camera. It is the first twilight polarization measurements set in the polar region and the first one during the winter and early spring epoch. The general polarization properties of the twilight sky and single scattering separation procedure are described. The basic results are the Boltzmann temperature decrease above 70 km and lack of mesosphere dust that is typical for this season.

  19. Software-defined Radio Based Measurement Platform for Wireless Networks.

    Science.gov (United States)

    Chao, I-Chun; Lee, Kang B; Candell, Richard; Proctor, Frederick; Shen, Chien-Chung; Lin, Shinn-Yan

    2015-10-01

    End-to-end latency is critical to many distributed applications and services that are based on computer networks. There has been a dramatic push to adopt wireless networking technologies and protocols (such as WiFi, ZigBee, WirelessHART, Bluetooth, ISA100.11a, etc.) into time-critical applications. Examples of such applications include industrial automation, telecommunications, power utility, and financial services. While performance measurement of wired networks has been extensively studied, measuring and quantifying the performance of wireless networks face new challenges and demand different approaches and techniques. In this paper, we describe the design of a measurement platform based on the technologies of software-defined radio (SDR) and IEEE 1588 Precision Time Protocol (PTP) for evaluating the performance of wireless networks.

  20. Radio-loud AGN-jet morphology and polarization: the role of ultra-high resolution radio surveys

    CERN Document Server

    Agudo, Ivan

    2016-01-01

    A review of the current challenges for the understanding of the physics of extragalactic radio jets from supermassive black holes is presented. Also, a prospect is given about how both very long baseline interferometry (VLBI) and polarimetric observations help us to understand their physics and the ones of their magnetic fields. This paper focuses on the impact that previous ultra-high resolution polarimetric surveys have had on our current knowledge on radio loud AGN. It first concentrates on the expectations about the improvement that the Square Kilometer Array, used as a super-sensitive VLBI station on existing and future very long baseline interferometric arrays, will provide in terms of access to new source classes, and in terms of a deeper portion of the Universe than currently accessible. A series of key new radio loud AGN science fields, to be opened by the Square Kilometer Array, are outlined together with a collection of preliminary ideas about possible programs of interest to deep in such fields. T...

  1. Generalized formalisms of the radio interferometer measurement equation

    Science.gov (United States)

    Price, D. C.; Smirnov, O. M.

    2015-05-01

    The radio interferometer measurement equation (RIME) is a matrix-based mathematical model that describes the response of a radio interferometer. The Jones calculus it employs is not suitable for describing the analogue components of a telescope. This is because it does not consider the effect of impedance mismatches between components. This paper aims to highlight the limitations of Jones calculus, and suggests some alternative methods that are more applicable. We reformulate the RIME with a different basis that includes magnetic and mixed coherency statistics. We present a microwave network inspired 2N-port version of the RIME, and a tensor formalism based upon the electromagnetic tensor from special relativity. We elucidate the limitations of the Jones-matrix-based RIME for describing analogue components. We show how measured scattering parameters of analogue components can be used in a 2N-port version of the RIME. In addition, we show how motion at relativistic speed affects the observed flux. We present reformulations of the RIME that correctly account for magnetic field coherency. These reformulations extend the standard formulation, highlight its limitations, and may have applications in space-based interferometry and precise absolute calibration experiments.

  2. Generalized Formalisms of the Radio Interferometer Measurement Equation

    CERN Document Server

    Price, Danny C

    2015-01-01

    The Radio Interferometer Measurement Equation (RIME) is a matrix-based mathematical model that describes the response of a radio interferometer. The Jones calculus it employs is not suitable for describing the analogue components of a telescope. This is because it does not consider the effect of impedance mismatches between components. This paper aims to highlight the limitations of Jones calculus, and suggests some alternative methods that are more applicable. We reformulate the RIME with a different basis that includes magnetic and mixed coherency statistics. We present a microwave network inspired 2N-port version of the RIME, and a tensor formalism based upon the electromagnetic tensor from special relativity. We elucidate the limitations of the Jones-matrix-based RIME for describing analogue components. We show how measured scattering parameters of analogue components can be used in a 2N-port version of the RIME. In addition, we show how motion at relativistic speed affects the observed flux. We present r...

  3. GaN layers with different polarities prepared by radio frequency molecular beam epitaxy and characterized by Raman scattering

    Institute of Scientific and Technical Information of China (English)

    Zhong Fei; Li Xin-Hua; Qiu Kai; Yin Zhi-Jun; Ji Chang-Jian; Cao Xian-Cun; Han Qi-Feng; Chen Jia-Rong; Wang Yu-Qi

    2007-01-01

    GaN layers with different polarities have been prepared by radio-frequency molecular beam epitaxy (RF-MBE) and characterized by Raman scattering. Polarity control are realized by controlling Al/N flux ratio during high temperature AlN buffer growth. The Raman results illustrate that the N-polarity GaN films have frequency shifts at A1(LO) mode because of their high carrier density; the forbidden A1 (TO) mode occurs for mixed-polarity GaN films due to the destroyed translation symmetry by inversion domain boundaries (IDBS); Raman spectra for Ga-polarity GaN films show that they have neither frequency shifts mode nor forbidden mode. These results indicate that Ga-polarity GaN films have a better quality, and they are in good agreement with the results obtained from the room temperature Hall mobility. The best values of Ga-polarity GaN films are 1042 cm2/Vs with a carrier density of 1.0×1017 cm-3.

  4. Design of a Device for Sky Light Polarization Measurements

    Directory of Open Access Journals (Sweden)

    Yujie Wang

    2014-08-01

    Full Text Available ky polarization patterns can be used both as indicators of atmospheric turbidity and as a sun compass for navigation. The objective of this study is to improve the precision of sky light polarization measurements by optimal design of the device used. The central part of the system is composed of a Charge Coupled Device (CCD camera; a fish-eye lens and a linear polarizer. Algorithms for estimating parameters of the polarized light based on three images are derived and the optimal alignments of the polarizer are analyzed. The least-squares estimation is introduced for sky light polarization pattern measurement. The polarization patterns of sky light are obtained using the designed system and they follow almost the same patterns of the single-scattering Rayleigh model. Deviations of polarization angles between observation and the theory are analyzed. The largest deviations occur near the sun and anti-sun directions. Ninety percent of the deviations are less than 5° and 40% percent of them are less than 1°. The deviations decrease evidently as the degree of polarization increases. It also shows that the polarization pattern of the cloudy sky is almost identical as in the blue sky.

  5. Improved degree of polarization-based differential group delay measurements.

    Science.gov (United States)

    Pye, Jason; Yevick, David

    2014-06-01

    The time-averaged Stokes vectors obtained after polarization-scrambled light containing multiple, independently polarized frequency components traverses an optical fiber collectively form a surface in Stokes space. The geometry of this surface can be directly related to the polarization mode dispersion of the fiber. This paper examines both numerically and experimentally an improved method for performing such measurements. Additionally, it quantifies the surfaces associated with input pulses containing an arbitrary set of equally spaced frequencies.

  6. Polarization Measurements in Photoproduction with CEBAF Large Acceptance Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    E. Pasyuk

    2010-05-01

    A significant part of the experimental program in Hall-B of the Jefferson Lab is dedicated to the studies of the structure of baryons. CEBAF Large Acceptance Spectrometer (CLAS), availability of circularly and linearly polarized photon beams and recent addition of polarized targets provides remarkable opportunity for single, double and in some cases triple polarization measurements in photoproduction. An overview of the experiments will be presented.

  7. XTE J1752-223 in outburst: a persistent radio jet, dramatic flaring, multiple ejections and linear polarization

    Science.gov (United States)

    Brocksopp, C.; Corbel, S.; Tzioumis, A.; Broderick, J. W.; Rodriguez, J.; Yang, J.; Fender, R. P.; Paragi, Z.

    2013-06-01

    The black hole candidate, XTE J1752-223, was discovered in 2009 October when it entered an outburst. We obtained radio data from the Australia Telescope Compact Array for the duration of the ˜9 month event. The light curves show that the radio emission from the compact jet persisted for the duration of an extended hard state and through the transition to the intermediate state. The flux then rose rapidly by a factor of 10 and the radio source entered a series of at least seven maxima, the first of which was likely to be emission associated with the compact jet. The subsequent six flares were accompanied by variable behaviour in terms of radio spectrum, degree of linear polarization, morphology and associated X-ray behaviour. They were, however, remarkably similar in terms of the estimated minimum power required to launch such an ejection event. We compare the timing of radio peaks with the location of the ejecta, imaged by contemporaneous Very Long Baseline Interferometry experiments. We then discuss the mechanism behind the events, in terms of whether discrete ejections are the most likely description of the behaviour. One ejection, at least, appears to be travelling with apparent superluminal motion. The range of properties, however, suggests that multiple mechanisms may be relevant and that at least some of the emission is coming from shocked interactions amongst the ejecta and between the ejecta and the interstellar medium. We also compare the radio flux density with the X-ray source during the hard state and conclude that XTE J1752-223 is a radio-weak/X-ray-bright outlier on the universal correlation for black hole transient sources.

  8. Polarization of the Poor: Multivariate Relative Poverty Measurement Sans Frontiers

    OpenAIRE

    Gordon Anderson

    2009-01-01

    A major impediment to poverty evaluation in multivariate environments are the difficulties associated with formulating poverty frontiers. This paper proposes a new multivariate polarization measure which, in appropriate circumstances, works as a multivariate poverty measure which does not require computation of a poverty frontier. As a poverty measure it has the intuitive appeal of reflecting the degree to which societies poor and non-poor are polarized. (The measure would also have considera...

  9. Polarization features of the ELF emissions excited in the outer ionosphere through modification of the ionospheric F-region by high-power HF radio emission

    Science.gov (United States)

    Belov, Alexey

    indent=1cm The results of in-situ measurements performed by the onboard equipment of the DEMETER satellite show that the guided ELF emissions can be excited through modification of the ionospheric F-region by high-power HF radio emission from the SURA heating facility. The power spectra of the excited ELF waves have a sharp upper frequency cutoff at the local proton gyrofrequency. In this work, we study the propagation and polarization characteristics of the observed ELF emissions using multicomponent measurement of electric and magnetic fields from the DEMETER satellite. For analysis we make use of singular value decomposition (SVD) technique. It is shown that the polar angle of the observed emissions wave vector with respect to ambient magnetic field is less than pi/6. The waves propagate upward in the left-hand-polarized mode. The wave polarization changes from right- to left-handed at the so-called crossover frequency. The obtained results improve the understanding of the generation mechanisms of observed ELF emissions. This work was supported by the Russian Foundation for Basic Research (project No. 12-02-00747-a), and the Government of the Russian Federation (contract No. 11.G34.31.0048).

  10. Cross-polarization from quadrupolar nuclei to silicon using low-radio-frequency amplitudes during magic-angle spinning

    Energy Technology Data Exchange (ETDEWEB)

    De Paul, S.M.; Ernst, M.; Shore, J.S.; Pines, A. [Lawrence Berkeley National Lab., CA (United States)]|[Univ. of California, Berkeley, CA (United States); Stebbins, J.F. [Stanford Univ., CA (United States)

    1997-04-17

    The dynamics of cross-polarization from the central transition of a quadrupolar nucleus ({sup 27}Al or {sup 23}Na) to a spin-1/2 nucleus ({sup 29}Si) during magic-angle spinning and using low-radio-frequency field strengths are analyzed for the mineral low albite. Under these conditions additional complications in the spin-lock behavior of the quadrupolar nucleus and in the cross-polarization process were found experimentally and are examined in detail. A step-by-step procedure for optimizing cross-polarization from the central transition of a quadrupolar nucleus to a spin-1/2 nucleus is described. Significant enhancement of {sup 29}Si NMR sensitivity and several applications are demonstrated. 50 refs., 8 figs., 4 tabs.

  11. On the Statistical Analysis of X-ray Polarization Measurements

    CERN Document Server

    Strohmayer, Tod E

    2013-01-01

    In many polarimetry applications, including observations in the X-ray band, the measurement of a polarization signal can be reduced to the detection and quantification of a deviation from uniformity of a distribution of measured angles. We explore the statistics of such polarization measurements using Monte Carlo simulations and chi-squared fitting methods. We compare our results to those derived using the traditional probability density used to characterize polarization measurements and quantify how they deviate as the intrinsic modulation amplitude grows. We derive relations for the number of counts required to reach a given detection level (parameterized by beta, the "number of sigma's" of the measurement) appropriate for measuring the modulation amplitude by itself (single interesting parameter case) or jointly with the position angle (two interesting parameters case). We show that for the former case when the intrinsic amplitude is equal to the well known minimum detectable polarization (MDP) it is, on a...

  12. Circular polarization measurements with a Ge(Li) detector

    DEFF Research Database (Denmark)

    Kopecký, J.; Warming, Inge Elisabeth

    1969-01-01

    This paper presents the results obtained in measurements of the degree of circular polarization of gamma transitions to bound states of 33S, 36Cl, 49Ti, 56Mn, 57Fe, 60Co and 64Cu following the capture of polarized thermal neutrons. Spin values have been determined on the basis of these results....

  13. Measurements of optical polarization properties in dental tissues and biomaterials

    Science.gov (United States)

    Fernández-Oliveras, Alicia; Pecho, Oscar E.; Rubiño, Manuel; Pérez, María M.

    2011-05-01

    Since biological tissues can have the intrinsic property of altering the polarization of incident light, optical polarization studies are important for a complete characterization. We have measured the polarized light scattered off of different dental tissues and biomaterials for a comparative study of their optical polarization property. The experimental setup was composed by a He-Ne laser, two linear polarizers and a detection system based on a photodiode. The laser beam was passed through one linear polarizer placed in front of the sample, beyond which the second linear polarizer (analyzer) and the photodiode detector were placed. First, the maximum laser-light intensity (reference condition) was attained without the sample in the laser path. Then, the sample was placed between the two polarizers and the polarization shift of the scattered laser light was determined by rotating the analyzer until the reference condition was reached. Two dental-resin composites (nanocomposite and hybrid) and two human dental tissues (enamel and dentine) were analyzed under repeatability conditions at three different locations on the sample: 20 measurements of the shift were taken and the average value and the uncertainty associated were calculated. For the human dentine the average value of the polarization shift found was 7 degrees, with an associated uncertainty of 2 degrees. For the human enamel and both dental-resin composites the average shift values were found to be similar to their corresponding uncertainties (2 degrees). The results suggest that although human dentine has notable polarization properties, dental-resin composites and human enamel do not show significant polarization shifts.

  14. Measures of quantum state purity and classical degree of polarization

    CERN Document Server

    Gamel, Omar

    2013-01-01

    There is a well-known mathematical similarity between two-dimensional classical polarization optics and two-level quantum systems, where the Poincare and Bloch spheres are identical mathematical structures. This analogy implies that the classical degree of polarization and quantum purity are in fact the same quantity. We make extensive use of this analogy to analyze various measures of polarization for higher dimensions proposed in the literature, in particular the N = 3 case, illustrating interesting relationships that emerge as well as the advantages of each measure. We also propose a different class of measures of entanglement based on the purity of subsystems.

  15. The signal selection and processing method for polarization measurement radar

    Institute of Scientific and Technical Information of China (English)

    CHANG YuLiang; WANG XueSong; LI YongZhen; XIAO ShunPing

    2009-01-01

    Based on the ambiguity function, a novel signal processing method for the polarization measurement radar is developed. One advantage of this method is that the two orthogonal polarized signals do not have to be perpendicular to each other, which is required by traditional methods. The error due to the correlation of the two transmitting signals in the traditional method, can be reduced by this new approach. A concept called ambiguity function matrix (AFM) is introduced based on this method. AFM is a promising tool for the signal selection and design in the polarization scattering matrix measurement. The waveforms of the polarimetric radar are categorized and analyzed based on AFM in this paper. The signal processing flow of this method is explained. And the polarization scattering matrix measurement performance is testified by simulation. Furthermore, this signal processing method can be used in the inter-pulse interval measurement technique as well as in the instantaneous measurement technique.

  16. Radio Occultation Measurements of Pluto's Atmosphere with New Horizons

    Science.gov (United States)

    Hinson, David P.; Linscott, Ivan; Young, Leslie; Stern, S. Alan; Bird, Mike; Ennico, Kimberly; Gladstone, Randy; Olkin, Catherine B.; Pätzold, Martin; Strobel, Darrell F.; Summers, Michael; Tyler, G. Leonard; Weaver, Harold A.; Woods, Will; New Horizons Science Team

    2016-10-01

    The reconnaissance of the Pluto System by New Horizons in July 2015 included a radio occultation at Pluto. The observation was performed with signals transmitted simultaneously by four antennas of the NASA Deep Space Network, two at the Goldstone complex in California and two at the Canberra complex in Australia. Each antenna radiated 20 kW without modulation at a wavelength of 4.17 cm. New Horizons received the four signals with its 2.1-m high-gain antenna, where the signals were split into pairs and processed independently by two identical REX radio science instruments. Each REX relied on a different ultra-stable oscillator as its frequency reference. The signals were digitized and filtered, and the data samples were stored on the spacecraft for later transmission to Earth. Six months elapsed before all data had arrived on the ground, and the results reported here are the first to utilize the complete set of observations. Pluto's tenuous atmosphere is a significant challenge for radio occultation sounding, which led us to develop a specialized method of analysis. We began by calibrating each signal to remove effects not associated with Pluto's atmosphere, including the diffraction pattern from Pluto's surface. We reduced the noise and increased our sensitivity to the atmosphere by averaging the results from the four signals, while using other combinations of the signals to characterize the noise. We then retrieved profiles of number density, pressure, and temperature from the averaged phase profiles at both occultation entry and exit. Finally, we used a combination of analytical methods and Monte Carlo simulations to determine the accuracy of the measurements. The REX profiles provide the first direct measure of the surface pressure and temperature structure in Pluto's lower atmosphere. There are significant differences between the structure at entry (193.5°E, 17.0°S, sunset) and exit (15.7°E, 15.1°N, sunrise), which arise from spatial variations in surface

  17. The magnetic field and turbulence of the cosmic web measured using a brilliant fast radio burst

    CERN Document Server

    Ravi, V; Bailes, M; Bannister, K; Bhandari, S; Bhat, N D R; Burke-Spolaor, S; Caleb, M; Flynn, C; Jameson, A; Johnston, S; Keane, E F; Kerr, M; Tiburzi, C; Tuntsov, A V; Vedantham, H K

    2016-01-01

    Fast radio bursts (FRBs) are millisecond-duration events thought to originate beyond the Milky Way galaxy. Uncertainty surrounding the burst sources, and their propagation through intervening plasma, has limited their use as cosmological probes. We report on a mildly dispersed (dispersion measure 266.5+-0.1 pc cm^-3), exceptionally intense (120+-30 Jy), linearly polarized, scintillating burst (FRB 150807) that we directly localize to 9 arcmin^2. Based on a low Faraday rotation (12.0+-0.7 rad m^-2), we infer negligible magnetization in the circum-burst plasma and constrain the net magnetization of the cosmic web along this sightline to <21 nG, parallel to the line-of-sight. The burst scintillation suggests weak turbulence in the ionized intergalactic medium.

  18. Diffraction and polarization effects in Earth radiation budget measurements.

    Science.gov (United States)

    Mahan, J R; Barki, A R; Priestley, K J

    2016-12-01

    Thermal radiation emitted and reflected from the Earth and viewed from near-Earth orbit may be characterized by its spectral distribution, its degree of coherence, and its state of polarization. The current generation of broadband Earth radiation budget instruments has been designed to minimize the effect of diffraction and polarization on science products. We used Monte Carlo ray-trace (MCRT) models that treat individual rays as quasi-monochromatic, polarized entities to explore the possibility of improving the performance of such instruments by including measures of diffraction and polarization during calibration and operation. We have demonstrated that diffraction and polarization sensitivity associated with typical Earth radiation budget instrument design features has a negligible effect on measurements.

  19. Potential radio frequency interference with the GPS L5 band for radio occultation measurements

    Directory of Open Access Journals (Sweden)

    A. M. Wolff

    2014-05-01

    Full Text Available New Radio Occultation (RO receivers are planned to utilize the newly implemented Global Positioning System (GPS L5 signal centered at 1176.45 MHz. Since there are currently no operational GPS L5 receivers used for space-based RO applications, the interference environment is unclear. Distance Measuring Equipment (DME and Tactical Air Navigation (TACAN stations share the same frequency band as the GPS L5 signal. DME/TACAN signals have been identified to be a means of interference for any GPS L5 receiver. This study focuses on implementing a Systems Tools Kit (STK simulation to gain insight into the power received by a RO satellite in Low Earth Orbit (LEO from a DME/TACAN transmission. In order to confirm the validity of utilizing STK for communication purposes, a theoretical scenario was recreated as a simulation and the results were confirmed. Once the method was validated, STK was used to output a received power level aboard a RO satellite from a DME/TACAN station as well as a tool to predict the number of interfering DME/TACAN stations at any point in time. Taking a conservative approach, the signal power received was much greater than the typical power level received by a RO satellite from a GPS satellite transmission. This relatively high received power along with a high number of interfering DME/TACAN stations as an RO satellite passes over North America or Western Europe indicate that DME/TACAN interference may conflict with RO receivers.

  20. Performance measurement of broadband, wide-angle polarizing beam splitter

    Institute of Scientific and Technical Information of China (English)

    CHEN Wei-bin; ZHENG Zhen-rong; GU Pei-fu; ZHANG Yue-guang

    2007-01-01

    Polarizing beam splitter (PBS) is a critical optical component in projection display system because PBS performance greatly influences the contrast and brightness of the system. PBS performance is usually measured by spectrophotometer after coating and cementing, but the measured result cannot represent the actual performance in practice because people usually change the incident angle in one plane (horizontal plane) and do not consider the other plane (vertical plane). Geometrical polarization rotation occurring at reduced F-number influences the measuring precision of s-polarization transmittance (Ts) and p-polarization reflectance (Rp). A more accurate and practical way to measure the performance of broadband, wide-angle PBS is presented in this paper.

  1. HIGH-FIDELITY RADIO ASTRONOMICAL POLARIMETRY USING A MILLISECOND PULSAR AS A POLARIZED REFERENCE SOURCE

    Energy Technology Data Exchange (ETDEWEB)

    Van Straten, W., E-mail: vanstraten.willem@gmail.com [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, VIC 3122 (Australia)

    2013-01-15

    A new method of polarimetric calibration is presented in which the instrumental response is derived from regular observations of PSR J0437-4715 based on the assumption that the mean polarized emission from this millisecond pulsar remains constant over time. The technique is applicable to any experiment in which high-fidelity polarimetry is required over long timescales; it is demonstrated by calibrating 7.2 years of high-precision timing observations of PSR J1022+1001 made at the Parkes Observatory. Application of the new technique followed by arrival time estimation using matrix template matching yields post-fit residuals with an uncertainty-weighted standard deviation of 880 ns, two times smaller than that of arrival time residuals obtained via conventional methods of calibration and arrival time estimation. The precision achieved by this experiment yields the first significant measurements of the secular variation of the projected semimajor axis, the precession of periastron, and the Shapiro delay; it also places PSR J1022+1001 among the 10 best pulsars regularly observed as part of the Parkes Pulsar Timing Array (PPTA) project. It is shown that the timing accuracy of a large fraction of the pulsars in the PPTA is currently limited by the systematic timing error due to instrumental polarization artifacts. More importantly, long-term variations of systematic error are correlated between different pulsars, which adversely affects the primary objectives of any pulsar timing array experiment. These limitations may be overcome by adopting the techniques presented in this work, which relax the demand for instrumental polarization purity and thereby have the potential to reduce the development cost of next-generation telescopes such as the Square Kilometre Array.

  2. Radio Astronomers Set New Standard for Accurate Cosmic Distance Measurement

    Science.gov (United States)

    1999-06-01

    A team of radio astronomers has used the National Science Foundation's Very Long Baseline Array (VLBA) to make the most accurate measurement ever made of the distance to a faraway galaxy. Their direct measurement calls into question the precision of distance determinations made by other techniques, including those announced last week by a team using the Hubble Space Telescope. The radio astronomers measured a distance of 23.5 million light-years to a galaxy called NGC 4258 in Ursa Major. "Ours is a direct measurement, using geometry, and is independent of all other methods of determining cosmic distances," said Jim Herrnstein, of the National Radio Astronomy Observatory (NRAO) in Socorro, NM. The team says their measurement is accurate to within less than a million light-years, or four percent. The galaxy is also known as Messier 106 and is visible with amateur telescopes. Herrnstein, along with James Moran and Lincoln Greenhill of the Harvard- Smithsonian Center for Astrophysics; Phillip Diamond, of the Merlin radio telescope facility at Jodrell Bank and the University of Manchester in England; Makato Inoue and Naomasa Nakai of Japan's Nobeyama Radio Observatory; Mikato Miyoshi of Japan's National Astronomical Observatory; Christian Henkel of Germany's Max Planck Institute for Radio Astronomy; and Adam Riess of the University of California at Berkeley, announced their findings at the American Astronomical Society's meeting in Chicago. "This is an incredible achievement to measure the distance to another galaxy with this precision," said Miller Goss, NRAO's Director of VLA/VLBA Operations. "This is the first time such a great distance has been measured this accurately. It took painstaking work on the part of the observing team, and it took a radio telescope the size of the Earth -- the VLBA -- to make it possible," Goss said. "Astronomers have sought to determine the Hubble Constant, the rate of expansion of the universe, for decades. This will in turn lead to an

  3. POLARBEAR-2: an instrument for CMB polarization measurements

    CERN Document Server

    Inoue, Y; Akiba, Y; Aleman, C; Arnold, K; Baccigalupi, C; Barch, B; Barron, D; Bender, A; Boettger, D; Borrill, J; Chapman, S; Chinone, Y; Cukierman, A; de Haan, T; Dobbs, M A; Ducout, A; Dunner, R; Elleflot, T; Errard, J; Fabbian, G; Feeney, S; Feng, C; Fuller, G; Gilbert, A J; Goeckner-Wald, N; Groh, J; Hall, G; Halverson, N; Hamada, T; Hasegawa, M; Hattori, K; Hazumi, M; Hill, C; Holzapfel, W L; Hori, Y; Howe, L; Irie, F; Jaehnig, G; Jaffe, A; Jeongh, O; Katayama, N; Kaufman, J P; Kazemzadeh, K; Keating, B G; Kermish, Z; Keskital, R; Kisner, T; Kusaka, A; Jeune, M Le; Lee, A T; Leon, D; Linder, E V; Lowry, L; Matsuda, F; Matsumura, T; Miller, N; Mizukami, K; Montgomery, J; Navaroli, M; Nishino, H; Paar, H; Peloton, J; Poletti, D; Puglisi, G; Raum, C R; Rebeiz, G M; Reichardt, C L; Richards, P L; Ross, C; Rotermund, K M; Segaw, Y; Sherwin, B D; Shirley, I; Siritanasak, P; Stebor, N; Suzuki, R Stompor A; Tajima, O; Takada, S; Takatori, S; Teply, G P; Tikhomirol, A; Tomaru, T; Whitehorn, N; Zahn, A; Zahn, O

    2016-01-01

    POLARBEAR-2 (PB-2) is a cosmic microwave background (CMB) polarization experiment that will be located in the Atacama highland in Chile at an altitude of 5200 m. Its science goals are to measure the CMB polarization signals originating from both primordial gravitational waves and weak lensing. PB-2 is designed to measure the tensor to scalar ratio, r, with precision {\\sigma}(r) < 0.01, and the sum of neutrino masses, {\\Sigma}m{\

  4. Polarization measurement and vertical aperture optimization for obtaining circularly polarized bend-magnet radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kortright, J.B.; Rice, M.; Hussain, Z. [Lawrence Berkeley National Lab., CA (United States)] [and others

    1997-04-01

    Growing interest in utilizing circular polarization prompted the design of bend-magnet beamline 9.3.2 at the Advanced Light Source, covering the 30-1500 eV spectral region, to include vertical aperturing capabilities for optimizing the collection of circular polarization above and below the orbit plane. After commissioning and early use of the beamline, a multilayer polarimeter was used to characterize the polarization state of the beam as a function of vertical aperture position. This report partially summarizes the polarimetry measurements and compares results with theoretical calculations intended to simulate experimental conditions.

  5. Polarized Reflectance Measurement of Burned Skin Tissues

    Science.gov (United States)

    de Pedro, Hector Michael; Chang, Chuan-I.; Zarnani, Faranak; Glosser, Robert; Maas, D.; Idris, A.

    2011-10-01

    In the US, there are over 400,000 burn victims with 3,500 deaths in 2010. Recent evidence suggests that early removal of burn tissues can significantly increase the success of their recovery, since burns continue to spread and damage surrounding tissues after hours of injury. The rationale behind this procedure is that burns trigger the body's immune system to overreact, causing additional damage. Therefore, it is important to distinguish burn areas so that it can be removed. The problem with this is that it is difficult to recognize the margins of the burn area. In our project, we use polarized reflectance as a tool to identify the burned tissues from unburned ones.

  6. On noise treatment in radio measurements of cosmic ray air showers

    CERN Document Server

    Schröder, F G; Arteaga, J C; Asch, T; Bähren, L; Bekk, K; Bertaina, M; Biermann, P L; Blümer, J; Bozdog, H; Brancus, I M; Buchholz, P; Buitink, S; Cantoni, E; Chiavassa, A; Daumiller, K; de Souza, V; Doll, P; Engel, R; Falcke, H; Finger, M; Fuhrmann, D; Gemmeke, H; Grupen, C; Haungs, A; Heck, D; Hörandel, J R; Horneffer, A; Huber, D; Huege, T; Isar, P G; Kampert, K -H; Kang, D; Krömer, O; Kuijpers, J; Lafebre, S; Link, K; Łuczak, P; Ludwig, M; Mathes, H J; Melissas, M; Morello, C; Nehls, S; Oehlschläger, J; Palmieri, N; Pierog, T; Rautenberg, J; Rebel, H; Roth, M; Rühle, C; Saftoiu, A; Schieler, H; Schmidt, A; Sima, O; Toma, G; Trinchero, G C; Weindl, A; Wochele, J; Wommer, M; Zabierowski, J

    2010-01-01

    Precise measurements of the radio emission by cosmic ray air showers require an adequate treatment of noise. Unlike to usual experiments in particle physics, where noise always adds to the signal, radio noise can in principle decrease or increase the signal if it interferes by chance destructively or constructively. Consequently, noise cannot simply be subtracted from the signal, and its influence on amplitude and time measurement of radio pulses must be studied with care. First, noise has to be determined consistently with the definition of the radio signal which typically is the maximum field strength of the radio pulse. Second, the average impact of noise on radio pulse measurements at individual antennas is studied for LOPES. It is shown that a correct treatment of noise is especially important at low signal-to-noise ratios: noise can be the dominant source of uncertainty for pulse height and time measurements, and it can systematically flatten the slope of lateral distributions. The presented method can ...

  7. Compressed Measurements Based Spectrum Sensing for Wideband Cognitive Radio Systems

    Directory of Open Access Journals (Sweden)

    Taha A. Khalaf

    2015-01-01

    Full Text Available Spectrum sensing is the most important component in the cognitive radio (CR technology. Spectrum sensing has considerable technical challenges, especially in wideband systems where higher sampling rates are required which increases the complexity and the power consumption of the hardware circuits. Compressive sensing (CS is successfully deployed to solve this problem. Although CS solves the higher sampling rate problem, it does not reduce complexity to a large extent. Spectrum sensing via CS technique is performed in three steps: sensing compressed measurements, reconstructing the Nyquist rate signal, and performing spectrum sensing on the reconstructed signal. Compressed detectors perform spectrum sensing from the compressed measurements skipping the reconstruction step which is the most complex step in CS. In this paper, we propose a novel compressed detector using energy detection technique on compressed measurements sensed by the discrete cosine transform (DCT matrix. The proposed algorithm not only reduces the computational complexity but also provides a better performance than the traditional energy detector and the traditional compressed detector in terms of the receiver operating characteristics. We also derive closed form expressions for the false alarm and detection probabilities. Numerical results show that the analytical expressions coincide with the exact probabilities obtained from simulations.

  8. Polarization dependence of Z-scan measurement: theory and experiment.

    Science.gov (United States)

    Yan, Xiao-Qing; Liu, Zhi-Bo; Zhang, Xiao-Liang; Zhou, Wen-Yuan; Tian, Jian-Guo

    2009-04-13

    Here we report on an extension of common Z-scan method to arbitrary polarized incidence light for measurements of anisotropic third-order nonlinear susceptibility in isotropic medium. The normalized transmittance formulas of closed-aperture Z-scan are obtained for linearly, elliptically and circularly polarized incidence beam. The theoretical analysis is examined experimentally by studying third-order nonlinear susceptibility of CS2 liquid. Results show that the elliptically polarized light Z-scan method can be used to measure simultaneously the two third-order nonlinear susceptibility components chi(3)(xyyx) and chi(3)(xxyy). Furthermore, the elliptically polarized light Z-scan measurements of large nonlinear phase shift are also analyzed theoretically and experimentally.

  9. Accelerator Measurements of Magnetically Induced Radio Emission from Particle Cascades with Applications to Cosmic-Ray Air Showers.

    Science.gov (United States)

    Belov, K; Mulrey, K; Romero-Wolf, A; Wissel, S A; Zilles, A; Bechtol, K; Borch, K; Chen, P; Clem, J; Gorham, P W; Hast, C; Huege, T; Hyneman, R; Jobe, K; Kuwatani, K; Lam, J; Liu, T C; Nam, J; Naudet, C; Nichol, R J; Rauch, B F; Rotter, B; Saltzberg, D; Schoorlemmer, H; Seckel, D; Strutt, B; Vieregg, A G; Williams, C

    2016-04-08

    For 50 years, cosmic-ray air showers have been detected by their radio emission. We present the first laboratory measurements that validate electrodynamics simulations used in air shower modeling. An experiment at SLAC provides a beam test of radio-frequency (rf) radiation from charged particle cascades in the presence of a magnetic field, a model system of a cosmic-ray air shower. This experiment provides a suite of controlled laboratory measurements to compare to particle-level simulations of rf emission, which are relied upon in ultrahigh-energy cosmic-ray air shower detection. We compare simulations to data for intensity, linearity with magnetic field, angular distribution, polarization, and spectral content. In particular, we confirm modern predictions that the magnetically induced emission in a dielectric forms a cone that peaks at the Cherenkov angle and show that the simulations reproduce the data within systematic uncertainties.

  10. Accelerator Measurements of Magnetically Induced Radio Emission from Particle Cascades with Applications to Cosmic-Ray Air Showers

    Science.gov (United States)

    Belov, K.; Mulrey, K.; Romero-Wolf, A.; Wissel, S. A.; Zilles, A.; Bechtol, K.; Borch, K.; Chen, P.; Clem, J.; Gorham, P. W.; Hast, C.; Huege, T.; Hyneman, R.; Jobe, K.; Kuwatani, K.; Lam, J.; Liu, T. C.; Nam, J.; Naudet, C.; Nichol, R. J.; Rauch, B. F.; Rotter, B.; Saltzberg, D.; Schoorlemmer, H.; Seckel, D.; Strutt, B.; Vieregg, A. G.; Williams, C.; T-510 Collaboration

    2016-04-01

    For 50 years, cosmic-ray air showers have been detected by their radio emission. We present the first laboratory measurements that validate electrodynamics simulations used in air shower modeling. An experiment at SLAC provides a beam test of radio-frequency (rf) radiation from charged particle cascades in the presence of a magnetic field, a model system of a cosmic-ray air shower. This experiment provides a suite of controlled laboratory measurements to compare to particle-level simulations of rf emission, which are relied upon in ultrahigh-energy cosmic-ray air shower detection. We compare simulations to data for intensity, linearity with magnetic field, angular distribution, polarization, and spectral content. In particular, we confirm modern predictions that the magnetically induced emission in a dielectric forms a cone that peaks at the Cherenkov angle and show that the simulations reproduce the data within systematic uncertainties.

  11. Amplitude calibration of a digital radio antenna array for measuring cosmic ray air showers

    CERN Document Server

    Nehls, S; Arts, M J; Bluemer, J; Bozdog, H; van Cappellen, W A; Falcke, H; Haungs, A; Horneffer, A; Huege, T; Isar, P G; Krömer, O

    2008-01-01

    Radio pulses are emitted during the development of air showers, where air showers are generated by ultra-high energy cosmic rays entering the Earth's atmosphere. These nanosecond short pulses are presently investigated by various experiments for the purpose of using them as a new detection technique for cosmic particles. For an array of 30 digital radio antennas (LOPES experiment) an absolute amplitude calibration of the radio antennas including the full electronic chain of the data acquisition system is performed, in order to estimate absolute values of the electric field strength for these short radio pulses. This is mandatory, because the measured radio signals in the MHz frequency range have to be compared with theoretical estimates and with predictions from Monte Carlo simulations to reconstruct features of the primary cosmic particle. A commercial reference radio emitter is used to estimate frequency dependent correction factors for each single antenna of the radio antenna array. The expected received p...

  12. Altitudinal dependence of meteor radio afterglows measured via optical counterparts

    CERN Document Server

    Obenberger, K S; Dowell, J D; Schinzel, F K; Stovall, K; Sutton, E K; Taylor, G B

    2016-01-01

    Utilizing the all-sky imaging capabilities of the LWA1 radio telescope along with a host of all-sky optical cameras, we have now observed 44 optical meteor counterparts to radio afterglows. Combining these observations we have determined the geographic positions of all 44 afterglows. Comparing the number of radio detections as a function of altitude above sea level to the number of expected bright meteors we find a strong altitudinal dependence characterized by a cutoff below $\\sim$ 90 km, below which no radio emission occurs, despite the fact that many of the observed optical meteors penetrated well below this altitude. This cutoff suggests that wave damping from electron collisions is an important factor for the evolution of radio afterglows, which agrees with the hypothesis that the emission is the result of electron plasma wave emission.

  13. A New Approach to Suppress the Effect of Machining Error for Waveguide Septum Circular Polarizer at 230 GHz Band in Radio Astronomy

    Science.gov (United States)

    Hasegawa, Yutaka; Harada, Ryohei; Tokuda, Kazuki; Kimura, Kimihiro; Ogawa, Hideo; Onishi, Toshikazu; Nishimura, Atsushi; Han, Johnson; Inoue, Makoto

    2017-02-01

    A new stepped septum-type waveguide circular polarizer (SST-CP) was developed to operate in the 230 GHz band for radio astronomy, especially submillimeter-band VLBI observations. For previously reported SST-CP models, the 230 GHz band is too high to achieve the design characteristics in manufactured devices because of unexpected machining errors. To realize a functional SST-CP that can operate in the submillimeter band, a new method was developed, in which the division surface is shifted from the top step of the septum to the second step from the top, and we simulated the expected machining error. The SST-CP using this method can compensate for specified machining errors and suppress serious deterioration. To verify the proposed method, several test pieces were manufactured, and their characteristics were measured using a VNA. These results indicated that the insertion losses were approximately 0.75 dB, and the input return losses and the crosstalk of the left- and right-hand circular polarization were greater than 20 dB at 220-245 GHz on 300 K. Moreover, a 230 GHz SST-CP was developed by the proposed method and installed in a 1.85-m radio telescope receiver systems, and then had used for scientific observations during one observation season without any problems. These achievements demonstrate the successful development of a 230 GHz SST-CP for radio astronomical observations. Furthermore, the proposed method can be applicable for observations in higher frequency bands, such as 345 GHz.

  14. Measuring the influence of aerosols and albedo on sky polarization.

    Science.gov (United States)

    Kreuter, A; Emde, C; Blumthaler, M

    2010-11-01

    All-sky distributions of the polarized radiance are measured using an automated fish-eye camera system with a rotating polarizer. For a large range of aerosol and surface albedo situations, the influence on the degree of polarization and sky radiance is investigated. The range of aerosol optical depth and albedo is 0.05-0.5 and 0.1-0.75, respectively. For this range of parameters, a reduction of the degree of polarization from about 0.7 to 0.4 was observed. The analysis is done for 90° scattering angle in the principal plane under clear sky conditions for a broadband channel of 450 ± 25 nm and solar zenith angles between 55° and 60°. Radiative transfer calculations considering three different aerosol mixtures are performed and and agree with the measurements within the statistical error.

  15. Measuring the polarization of a rapidly precessing deuteron beam

    Science.gov (United States)

    Bagdasarian, Z.; Bertelli, S.; Chiladze, D.; Ciullo, G.; Dietrich, J.; Dymov, S.; Eversmann, D.; Fanourakis, G.; Gaisser, M.; Gebel, R.; Gou, B.; Guidoboni, G.; Hejny, V.; Kacharava, A.; Kamerdzhiev, V.; Lehrach, A.; Lenisa, P.; Lorentz, B.; Magallanes, L.; Maier, R.; Mchedlishvili, D.; Morse, W. M.; Nass, A.; Oellers, D.; Pesce, A.; Prasuhn, D.; Pretz, J.; Rathmann, F.; Shmakova, V.; Semertzidis, Y. K.; Stephenson, E. J.; Stockhorst, H.; Ströher, H.; Talman, R.; Thörngren Engblom, P.; Valdau, Yu.; Weidemann, C.; Wüstner, P.

    2014-05-01

    This paper describes a time-marking system that enables a measurement of the in-plane (horizontal) polarization of a 0.97-GeV/c deuteron beam circulating in the Cooler Synchrotron (COSY) at the Forschungszentrum Jülich. The clock time of each polarimeter event is used to unfold the 120-kHz spin precession and assign events to bins according to the direction of the horizontal polarization. After accumulation for one or more seconds, the down-up scattering asymmetry can be calculated for each direction and matched to a sinusoidal function whose magnitude is proportional to the horizontal polarization. This requires prior knowledge of the spin tune or polarization precession rate. An initial estimate is refined by resorting the events as the spin tune is adjusted across a narrow range and searching for the maximum polarization magnitude. The result is biased toward polarization values that are too large, in part because of statistical fluctuations but also because sinusoidal fits to even random data will produce sizable magnitudes when the phase is left free to vary. An analysis procedure is described that matches the time dependence of the horizontal polarization to templates based on emittance-driven polarization loss while correcting for the positive bias. This information will be used to study ways to extend the horizontal polarization lifetime by correcting spin tune spread using ring sextupole fields and thereby to support the feasibility of searching for an intrinsic electric dipole moment using polarized beams in a storage ring. This paper is a combined effort of the Storage Ring EDM collaboration and the JEDI collaboration.

  16. Walkie-Talkie Measurements for the Speed of Radio Waves in Air

    Science.gov (United States)

    Dombi, Andra; Tunyagi, Arthur; Neda, Zoltan

    2013-01-01

    A handheld emitter-receiver device suitable for the direct estimation of the velocity of radio waves in air is presented. The velocity of radio waves is measured using the direct time-of-flight method, without the need for any tedious and precise settings. The results for two measurement series are reported. Both sets of results give an estimate…

  17. Walkie-Talkie Measurements for the Speed of Radio Waves in Air

    Science.gov (United States)

    Dombi, Andra; Tunyagi, Arthur; Neda, Zoltan

    2013-01-01

    A handheld emitter-receiver device suitable for the direct estimation of the velocity of radio waves in air is presented. The velocity of radio waves is measured using the direct time-of-flight method, without the need for any tedious and precise settings. The results for two measurement series are reported. Both sets of results give an estimate…

  18. [Accuracy analysis on a sort of polarized measurement in remote sensing].

    Science.gov (United States)

    Chen, Li-gang; Hong, Jin; Qiao, Yan-li; Sun, Xiao-bing; Wang, Yuan-jun

    2008-10-01

    Angular error of polarizer in polarimetric measurement is an important element affecting the measurement accuracy of degree of polarization, so angular error of polarizer should be considered in remote sensing of high-accuracy quantitative polarization. Simulation study shows that polarimetric measurement is relative to the polarization state (polarization angle or degree of polarization) of incident light in a specific measurement system of polarization. In the measurement mode of polarizer setting (0 degree, 60 degrees, 120 degrees), there is a maximum error of polarization measurement at the 0 degree or 180 degrees polarization angle while a minimum error at the 30 degrees, 90 degrees and 150 degrees polarization angle; In the measurement mode of polarizer setting (0 degree, 45 degrees, 90 degrees), there is a maximum error of polarization measurement near the 45 degrees polarization angle while a minimum error at the 0 degree, 90 degrees and 135 degrees polarization angle. The larger degree of polarization of incident light often contributes to the bigger measurement error except for incident light with several polarization angles. So the polarization measurement may be evaluated by the average degree of polarizatioo of linearly polarized light introduced in this paper. It is indicated that the measurement mode of polarizer setting (0 degree, 60 degrees, 120 degrees) is better than that of (0 degree, 45 degrees, 90 degrees).

  19. An in situ measurement of the radio-frequency attenuation in ice at Summit Station, Greenland

    CERN Document Server

    Avva, J; Miki, C; Saltzberg, D; Vieregg, A G

    2014-01-01

    We report an in situ measurement of the electric field attenuation length at radio frequencies for the bulk ice at Summit Station, Greenland, made by broadcasting radio-frequency signals vertically through the ice and measuring the relative power in the return ground bounce signal. We find the depth-averaged field attenuation length to be 947 +92/-85 meters at 75 MHz. While this measurement has clear radioglaciological applications, the radio clarity of the ice also has implications for the detection of ultra-high energy (UHE) astrophysical particles via their radio emission in dielectric media such as ice. The measured attenuation length at Summit Station is comparable to previously measured radio-frequency attenuation lengths at candidate particle detector sites around the world, and strengthens the case for Summit Station as the most promising northern site for UHE neutrino detection.

  20. SIMULTANEOUS MEASUREMENT OF CIRCULAR DICHROISM AND FLUORESCENCE POLARIZATION ANISOTROPY.

    Energy Technology Data Exchange (ETDEWEB)

    SUTHERLAND,J.C.

    2002-01-19

    Circular dichroism and fluorescence polarization anisotropy are important tools for characterizing biomolecular systems. Both are used extensively in kinetic experiments involving stopped- or continuous flow systems as well as titrations and steady-state spectroscopy. This paper presents the theory for determining circular dichroism and fluorescence polarization anisotropy simultaneously, thus insuring the two parameters are recorded under exactly the same conditions and at exactly the same time in kinetic experiments. The approach to measuring circular dichroism is that used in almost all conventional dichrographs. Two arrangements for measuring fluorescence polarization anisotropy are described. One uses a single fluorescence detector and signal processing with a lock-in amplifier that is similar to the measurement of circular dichroism. The second approach uses classic ''T'' format detection optics, and thus can be used with conventional photon-counting detection electronics. Simple extensions permit the simultaneous measurement of the absorption and excitation intensity corrected fluorescence intensity.

  1. MEASURING THE JET POWER OF FLAT-SPECTRUM RADIO QUASARS

    Energy Technology Data Exchange (ETDEWEB)

    Shabala, S. S.; Santoso, J. S. [School of Mathematics and Physics, University of Tasmania, Private Bag 37, Hobart, TAS 7001 (Australia); Godfrey, L. E. H. [International Centre for Radio Astronomy Research, Curtin University, GPO Box U1987, Perth, Western Australia 6845 (Australia)

    2012-09-10

    We use frequency-dependent position shifts of flat-spectrum radio cores to estimate the kinetic power of active galactic nucleus (AGN) jets. We find a correlation between the derived jet powers and AGN narrow-line luminosity, consistent with the well-known relation for radio galaxies and steep spectrum quasars. This technique can be applied to intrinsically weak jets even at high redshift.

  2. Automation of Mode Locking in a Nonlinear Polarization Rotation Fiber Laser through Output Polarization Measurements.

    Science.gov (United States)

    Olivier, Michel; Gagnon, Marc-Daniel; Habel, Joé

    2016-02-28

    When a laser is mode-locked, it emits a train of ultra-short pulses at a repetition rate determined by the laser cavity length. This article outlines a new and inexpensive procedure to force mode locking in a pre-adjusted nonlinear polarization rotation fiber laser. This procedure is based on the detection of a sudden change in the output polarization state when mode locking occurs. This change is used to command the alignment of the intra-cavity polarization controller in order to find mode-locking conditions. More specifically, the value of the first Stokes parameter varies when the angle of the polarization controller is swept and, moreover, it undergoes an abrupt variation when the laser enters the mode-locked state. Monitoring this abrupt variation provides a practical easy-to-detect signal that can be used to command the alignment of the polarization controller and drive the laser towards mode locking. This monitoring is achieved by feeding a small portion of the signal to a polarization analyzer measuring the first Stokes parameter. A sudden change in the read out of this parameter from the analyzer will occur when the laser enters the mode-locked state. At this moment, the required angle of the polarization controller is kept fixed. The alignment is completed. This procedure provides an alternate way to existing automating procedures that use equipment such as an optical spectrum analyzer, an RF spectrum analyzer, a photodiode connected to an electronic pulse-counter or a nonlinear detecting scheme based on two-photon absorption or second harmonic generation. It is suitable for lasers mode locked by nonlinear polarization rotation. It is relatively easy to implement, it requires inexpensive means, especially at a wavelength of 1550 nm, and it lowers the production and operation costs incurred in comparison to the above-mentioned techniques.

  3. Measuring Political Polarization: Twitter shows the two sides of Venezuela

    CERN Document Server

    Morales, A J; Losada, J C; Benito, R M

    2015-01-01

    We say that a population is perfectly polarized when divided in two groups of the same size and opposite opinions. In this paper, we propose a methodology to study and measure the emergence of polarization from social interactions. We begin by proposing a model to estimate opinions in which a minority of influential individuals propagate their opinions through a social network. The result of the model is an opinion probability density function. Next, we propose an index to quantify the extent to which the resulting distribution is polarized. Finally, we apply the proposed methodology to a Twitter conversation about the late Venezuelan president, Hugo Ch\\'avez, finding a good agreement between our results and offline data. Hence, we show that our methodology can detect different degrees of polarization, depending on the structure of the network.

  4. Measuring political polarization: Twitter shows the two sides of Venezuela

    Science.gov (United States)

    Morales, A. J.; Borondo, J.; Losada, J. C.; Benito, R. M.

    2015-03-01

    We say that a population is perfectly polarized when divided in two groups of the same size and opposite opinions. In this paper, we propose a methodology to study and measure the emergence of polarization from social interactions. We begin by proposing a model to estimate opinions in which a minority of influential individuals propagate their opinions through a social network. The result of the model is an opinion probability density function. Next, we propose an index to quantify the extent to which the resulting distribution is polarized. Finally, we apply the proposed methodology to a Twitter conversation about the late Venezuelan president, Hugo Chávez, finding a good agreement between our results and offline data. Hence, we show that our methodology can detect different degrees of polarization, depending on the structure of the network.

  5. Radio polarization maps of shell-type SNRs I. Effects of a random magnetic field component, and thin-shell models

    CERN Document Server

    Bandiera, Rino

    2016-01-01

    The maps of intensity and polarization of the radio synchrotron emission from shell-type supernova remnants (SNRs) contain a considerable amount of information, although of not easy interpretation. With the aim of deriving constraints on the 3-D spatial distribution of the emissivity, as well as on the structure of both ordered and random magnetic fields (MFs), we present here a scheme to model maps of the emission and polarization in SNRs. We first generalize the classical treatment of the synchrotron emission to the case in which the MF is composed by an ordered MF plus an isotropic random component, with arbitrary relative strengths. In the case of a power-law particle energy distribution, we derive analytic formulae that formally resemble those for the classical case. We also treat the case of a shock compression of a fully random upstream field and we predict that the polarization fraction in this case should be higher than typically measured in SNRs. We implement the above treatment into a code, which s...

  6. Correcting systematic errors in high-sensitivity deuteron polarization measurements

    Energy Technology Data Exchange (ETDEWEB)

    Brantjes, N.P.M. [Kernfysisch Versneller Instituut, University of Groningen, NL-9747AA Groningen (Netherlands); Dzordzhadze, V. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Gebel, R. [Institut fuer Kernphysik, Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany); Gonnella, F. [Physica Department of ' Tor Vergata' University, Rome (Italy); INFN-Sez. ' Roma tor Vergata,' Rome (Italy); Gray, F.E. [Regis University, Denver, CO 80221 (United States); Hoek, D.J. van der [Kernfysisch Versneller Instituut, University of Groningen, NL-9747AA Groningen (Netherlands); Imig, A. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Kruithof, W.L. [Kernfysisch Versneller Instituut, University of Groningen, NL-9747AA Groningen (Netherlands); Lazarus, D.M. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Lehrach, A.; Lorentz, B. [Institut fuer Kernphysik, Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany); Messi, R. [Physica Department of ' Tor Vergata' University, Rome (Italy); INFN-Sez. ' Roma tor Vergata,' Rome (Italy); Moricciani, D. [INFN-Sez. ' Roma tor Vergata,' Rome (Italy); Morse, W.M. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Noid, G.A. [Indiana University Cyclotron Facility, Bloomington, IN 47408 (United States); and others

    2012-02-01

    This paper reports deuteron vector and tensor beam polarization measurements taken to investigate the systematic variations due to geometric beam misalignments and high data rates. The experiments used the In-Beam Polarimeter at the KVI-Groningen and the EDDA detector at the Cooler Synchrotron COSY at Juelich. By measuring with very high statistical precision, the contributions that are second-order in the systematic errors become apparent. By calibrating the sensitivity of the polarimeter to such errors, it becomes possible to obtain information from the raw count rate values on the size of the errors and to use this information to correct the polarization measurements. During the experiment, it was possible to demonstrate that corrections were satisfactory at the level of 10{sup -5} for deliberately large errors. This may facilitate the real time observation of vector polarization changes smaller than 10{sup -6} in a search for an electric dipole moment using a storage ring.

  7. High-fidelity radio astronomical polarimetry using a millisecond pulsar as a polarized reference source

    CERN Document Server

    van Straten, W

    2012-01-01

    A new method of polarimetric calibration is presented in which the instrumental response is derived from regular observations of PSR J0437-4715 based on the assumption that the mean polarized emission from this millisecond pulsar remains constant over time. The technique is applicable to any experiment in which high-fidelity polarimetry is required over long time scales; it is demonstrated by calibrating 7.2 years of high-precision timing observations of PSR J1022+1001 made at the Parkes Observatory. Application of the new technique followed by arrival time estimation using matrix template matching yields post-fit residuals with an uncertainty-weighted standard deviation of 880 ns, two times smaller than that of arrival time residuals obtained via conventional methods of calibration and arrival time estimation. The precision achieved by this experiment yields the first significant measurements of the secular variation of the projected semi-major axis, the precession of periastron, and the Shapiro delay; it al...

  8. Heterodyne detector for measuring the characteristic of elliptically polarized microwaves

    DEFF Research Database (Denmark)

    Leipold, Frank; Nielsen, Stefan Kragh; Michelsen, Susanne

    2008-01-01

    In the present paper, a device is introduced, which is capable of determining the three characteristic parameters of elliptically polarized light (ellipticity, angle of ellipticity, and direction of rotation) for microwave radiation at a frequency of 110 GHz. The device consists of two...... be calculated. Results from measured and calculated wave characteristics of an elliptically polarized 110 GHz microwave beam for plasma heating launched into the TEXTOR-tokamak experiment are presented. Measurement and calculation are in good agreement. ©2008 American Institute of Physics...

  9. Measurement of $\\Lambda_{b}$ polarization in Z decays

    CERN Document Server

    Buskulic, Damir; De Bonis, I; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Odier, P; Pietrzyk, B; Chmeissani, M; Crespo, J M; Efthymiopoulos, I; Fernández, E; Fernández-Bosman, M; Garrido, L; Juste, A; Martínez, M; Orteu, S; Pacheco, A; Padilla, C; Palla, Fabrizio; Pascual, A; Perlas, J A; Riu, I; Sánchez, F; Teubert, F; Colaleo, A; Creanza, D; De Palma, M; Farilla, A; Gelao, G; Girone, M; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Natali, S; Nuzzo, S; Ranieri, A; Raso, G; Romano, F; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Alemany, R; Bazarko, A O; Bonvicini, G; Cattaneo, M; Comas, P; Coyle, P; Drevermann, H; Forty, Roger W; Frank, M; Hagelberg, R; Harvey, J; Jacobsen, R; Janot, P; Jost, B; Kneringer, E; Knobloch, J; Lehraus, Ivan; Martin, E B; Mato, P; Minten, Adolf G; Miquel, R; Mir, L M; Moneta, L; Oest, T; Palazzi, P; Pater, J R; Pusztaszeri, J F; Ranjard, F; Rensing, P E; Rolandi, Luigi; Schlatter, W D; Schmelling, M; Schneider, O; Tejessy, W; Tomalin, I R; Venturi, A; Wachsmuth, H W; Wildish, T; Witzeling, W; Wotschack, J; Ajaltouni, Ziad J; Bardadin-Otwinowska, Maria; Barrès, A; Boyer, C; Falvard, A; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Montret, J C; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rossignol, J M; Saadi, F; Fearnley, Tom; Hansen, J B; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Kyriakis, A; Markou, C; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Zachariadou, K; Blondel, A; Bonneaud, G R; Brient, J C; Bourdon, P; Rougé, A; Rumpf, M; Tanaka, R; Valassi, Andrea; Verderi, M; Videau, H L; Candlin, D J; Parsons, M I; Focardi, E; Parrini, G; Corden, M; Delfino, M C; Georgiopoulos, C H; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Passalacqua, L; Pepé-Altarelli, M; Curtis, L; Dorris, S J; Halley, A W; Knowles, I G; Lynch, J G; O'Shea, V; Raine, C; Reeves, P; Scarr, J M; Smith, K; Thompson, A S; Thomson, F; Thorn, S; Turnbull, R M; Becker, U; Braun, O; Geweniger, C; Graefe, G; Hanke, P; Hepp, V; Kluge, E E; Putzer, A; Rensch, B; Schmidt, M; Sommer, J; Stenzel, H; Tittel, K; Werner, S; Wunsch, M; Abbaneo, D; Beuselinck, R; Binnie, David M; Cameron, W; Colling, D J; Dornan, Peter J; Konstantinidis, N P; Moutoussi, A; Nash, J; San Martin, G; Sedgbeer, J K; Stacey, A M; Dissertori, G; Girtler, P; Kuhn, D; Rudolph, G; Bowdery, C K; Brodbeck, T J; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Sloan, Terence; Whelan, E P; Williams, M I; Galla, A; Greene, A M; Kleinknecht, K; Quast, G; Raab, J; Renk, B; Sander, H G; Wanke, R; Van Gemmeren, P; Zeitnitz, C; Aubert, Jean-Jacques; Bencheikh, A M; Benchouk, C; Bonissent, A; Bujosa, G; Calvet, D; Carr, J; Diaconu, C A; Etienne, F; Thulasidas, M; Nicod, D; Payre, P; Rousseau, D; Talby, M; Abt, I; Assmann, R W; Bauer, C; Blum, Walter; Brown, D; Dietl, H; Dydak, Friedrich; Ganis, G; Gotzhein, C; Jakobs, K; Kroha, H; Lütjens, G; Lutz, Gerhard; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Schael, S; Settles, Ronald; Seywerd, H C J; Saint-Denis, R; Wiedenmann, W; Wolf, G; Boucrot, J; Callot, O; Cordier, A; Courault, F; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Jacquet, M; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Nikolic, I A; Park, H J; Park, I C; Schune, M H; Simion, S; Veillet, J J; Videau, I; Azzurri, P; Bagliesi, G; Batignani, G; Bettarini, S; Bozzi, C; Calderini, G; Carpinelli, M; Ciocci, M A; Ciulli, V; Dell'Orso, R; Fantechi, R; Ferrante, I; Foà, L; Forti, F; Giassi, A; Giorgi, M A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Rizzo, G; Sanguinetti, G; Sciabà, A; Spagnolo, P; Steinberger, Jack; Tenchini, Roberto; Tonelli, G; Vannini, C; Verdini, P G; Walsh, J; Betteridge, A P; Blair, G A; Bryant, L M; Cerutti, F; Chambers, J T; Gao, Y; Green, M G; Johnson, D L; Medcalf, T; Perrodo, P; Strong, J A; Von Wimmersperg-Töller, J H; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Edwards, M; Maley, P; Norton, P R; Thompson, J C; Bloch-Devaux, B; Colas, P; Emery, S; Kozanecki, Witold; Lançon, E; Lemaire, M C; Locci, E; Marx, B; Pérez, P; Rander, J; Renardy, J F; Roussarie, A; Schuller, J P; Schwindling, J; Trabelsi, A; Vallage, B; Johnson, R P; Kim, H Y; Litke, A M; McNeil, M A; Taylor, G; Beddall, A; Booth, C N; Boswell, R; Brew, C A J; Cartwright, S L; Combley, F; Köksal, A; Letho, M; Newton, W M; Rankin, C; Reeve, J; Thompson, L F; Böhrer, A; Brandt, S; Cowan, G D; Feigl, E; Grupen, Claus; Lutters, G; Minguet-Rodríguez, J A; Rivera, F; Saraiva, P; Smolik, L; Stephan, F; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Musolino, G; Ragusa, F; Rothberg, J E; Wasserbaech, S R; Armstrong, S R; Bellantoni, L; Elmer, P; Feng, Z; Ferguson, D P S; Gao, Y S; González, S; Grahl, J; Greening, T C; Harton, J L; Hayes, O J; Hu, H; McNamara, P A; Nachtman, J M; Orejudos, W; Pan, Y B; Saadi, Y; Schmitt, M; Scott, I J; Sharma, V; Turk, J; Walsh, A M; Wu Sau Lan; Wu, X; Yamartino, J M; Zheng, M; Zobernig, G

    1996-01-01

    The \\Lambda_{\\mathrm{b}} polarization in hadronic \\mathrm{Z} decays is measured in semileptonic decays from the average energies of the charged lepton and the neutrino. In a data sample of approximately 3 million hadronic \\mathrm{Z} decays collected by the ALEPH detector at LEP between 1991 and 1994, 462\\pm 31 \\Lambda_{\\mathrm{b}} candidates are selected using (\\Lambda \\pi^+)--lepton correlations. From this event sample, the \\Lambda_{\\m athrm{b}} polarization is measured to be \\cal P_{\\Lambda_{\\mathrm{b}}}=-0.23^{+0.24}_{-0.20}(\\m athrm{stat}.)^{+0.08}_{-0.07} (\\mathrm{syst.})\\,.

  10. The shape of the radio wavefront of extensive air showers as measured with LOFAR

    NARCIS (Netherlands)

    Corstanje, A.; et al., [Unknown; Swinbank, J.

    2015-01-01

    Extensive air showers, induced by high energy cosmic rays impinging on the Earth’s atmosphere, produce radio emission that is measured with the LOFAR radio telescope. As the emission comes from a finite distance of a few kilometers, the incident wavefront is non-planar. A spherical, conical or hyper

  11. Measuring the Polarization of a Rapidly Precessing Deuteron Beam

    CERN Document Server

    Bagdasarian, Z; Chiladze, D; Ciullo, G; Dietrich, J; Dymov, S; Eversmann, D; Fanourakis, G; Gaisser, M; Gebel, R; Gou, B; Guidoboni, G; Hejny, V; Kacharava, A; Kamerdzhiev, V; Lehrach, A; Lenisa, P; Lorentz, B; Magallanes, L; Maier, R; Mchedlishvili, D; Morse, W M; Nass, A; Oellers, D; Pesce, A; Prasuhn, D; Pretz, J; Rathmann, F; Shmakova, V; Semertzidis, Y K; Stephenson, E J; Stockhorst, H; Ströher, H; Talman, R; Engblom, P Thörngren; Valdau, Yu; Weidemann, C; Wüstner, P

    2014-01-01

    This paper describes a time-marking system that enables a measurement of the in-plane (horizontal) polarization of a 0.97-GeV/c deuteron beam circulating in the Cooler Synchrotron (COSY) at the Forschungszentrum J\\"ulich. The clock time of each polarimeter event is used to unfold the 120-kHz spin precession and assign events to bins according to the direction of the horizontal polarization. After accumulation for one or more seconds, the down-up scattering asymmetry can be calculated for each direction and matched to a sinusoidal function whose magnitude is proportional to the horizontal polarization. This requires prior knowledge of the spin tune or polarization precession rate. An initial estimate is refined by re-sorting the events as the spin tune is adjusted across a narrow range and searching for the maximum polarization magnitude. The result is biased toward polarization values that are too large, in part because of statistical fluctuations but also because sinusoidal fits to even random data will prod...

  12. Dispersion Measure Variation of Repeating Fast Radio Burst Sources

    Science.gov (United States)

    Yang, Yuan-Pei; Zhang, Bing

    2017-09-01

    The repeating fast radio burst (FRB) 121102 was recently localized in a dwarf galaxy at a cosmological distance. The dispersion measure (DM) derived for each burst from FRB 121102 so far has not shown significant evolution, even though an apparent increase was recently seen with newly detected VLA bursts. It is expected that more repeating FRB sources may be detected in the future. In this work, we investigate a list of possible astrophysical processes that might cause DM variation of a particular FRB source. The processes include (1) cosmological scale effects such as Hubble expansion and large-scale structure fluctuations; (2) FRB local effects such as gas density fluctuation, expansion of a supernova remnant (SNR), a pulsar wind nebula, and an H ii region; and (3) the propagation effect due to plasma lensing. We find that the DM variations contributed by the large-scale structure are extremely small, and any observable DM variation is likely caused by the plasma local to the FRB source. In addition to mechanisms that decrease DM over time, we suggest that an FRB source in an expanding SNR around a nearly neutral ambient medium during the deceleration (Sedov–Taylor and snowplow) phases or in a growing H ii region can increase DM. Some effects (e.g., an FRB source moving in an H ii region or plasma lensing) can produce either positive or negative DM variations. Future observations of DM variations of FRB 121102 and other repeating FRB sources can provide important clues regarding the physical origin of these sources.

  13. Reconfigurable Wideband Circularly Polarized Stacked Square Patch Antenna for Cognitive Radios

    Science.gov (United States)

    Barbosa Kortright, Miguel A.; Waldstein, Seth W.; Simons, Rainee N.

    2017-01-01

    An almost square patch and a square patch with corner truncation for circularly polarized (CP) and a stacked CP square patch are researched and developed at X-band for cognitive devices. A draft set of presentation charts are attached.

  14. Simple measures of ozone depletion in the polar stratosphere

    Directory of Open Access Journals (Sweden)

    R. Müller

    2008-01-01

    Full Text Available We investigate the extent to which quantities that are based on total column ozone are applicable as measures of ozone loss in the polar vortices. Such quantities have been used frequently in ozone assessments by the World Meteorological Organization (WMO and also to assess the performance of chemistry-climate models. The most commonly considered quantities are March and October mean column ozone poleward of geometric latitude 63° and the spring minimum of daily total ozone minima poleward of a given latitude. Particularly in the Arctic, the former measure is affected by vortex variability and vortex break-up in spring. The minimum of daily total ozone minima poleward of a particular latitude is debatable, insofar as it relies on one single measurement or model grid point. We find that, for Arctic conditions, this minimum value often occurs in air outside the polar vortex, both in the observations and in a chemistry-climate model. Neither of the two measures shows a good correlation with chemical ozone loss in the vortex deduced from observations. We recommend that the minimum of daily minima should no longer be used when comparing polar ozone loss in observations and models. As an alternative to the March and October mean column polar ozone we suggest considering the minimum of daily average total ozone poleward of 63° equivalent latitude in spring (except for winters with an early vortex break-up. Such a definition both obviates relying on one single data point and reduces the impact of year-to-year variability in the Arctic vortex break-up on ozone loss measures. Further, this measure shows a reasonable correlation (r=–0.75 with observed chemical ozone loss. Nonetheless, simple measures of polar ozone loss must be used with caution; if possible, it is preferable to use more sophisticated measures that include additional information to disentangle the impact of transport and chemistry on ozone.

  15. Ultrasmall polarization rotation measurements via weak value amplification

    Energy Technology Data Exchange (ETDEWEB)

    Lima Bernardo, Bertúlio de, E-mail: bertulio@fisica.ufpb.br; Azevedo, Sérgio; Rosas, Alexandre

    2014-06-13

    Highlights: • We present a class of weak measurements where the measurer is an angular variable of the system. • Photon-energy qubits are required, which seems to be the first application of this kind of light. • Both weak optical activity and reflection-induced polarization rotation can be amplified. • This protocol can amplify the optical activity signal in nanostructures and biological tissues. - Abstract: We propose a framework to analyze weak measurements based on an angular version of the von Neumann measurement scheme, where the coupling between the system and the meter causes rotation of the measuring variable. We also discuss an experimental application of this theory in which measurements of weak optical activity and reflection-induced polarization rotation could be amplified in nearly two orders of magnitude. It can shed a new light on a great variety of physical chemistry, molecular biology and nanotechnology studies.

  16. Dual polarized receiving steering antenna array for measurement of ultrawideband pulse polarization structure

    Science.gov (United States)

    Balzovsky, E. V.; Buyanov, Yu. I.; Koshelev, V. I.; Nekrasov, E. S.

    2016-03-01

    To measure simultaneously two orthogonal components of the electromagnetic field of nano- and subnano-second duration, an antenna array has been developed. The antenna elements of the array are the crossed dipoles of dimension 5 × 5 cm. The arms of the dipoles are connected to the active four-pole devices to compensate the frequency response variations of a short dipole in the frequency band ranging from 0.4 to 4 GHz. The dipoles have superimposed phase centers allowing measuring the polarization structure of the field in different directions. The developed antenna array is the linear one containing four elements. The pattern maximum position is controlled by means of the switched ultrawideband true time delay lines. Discrete steering in seven directions in the range from -40° to +40° has been realized. The error at setting the pattern maximum position is less than 4°. The isolation of the polarization exceeds 29 dB in the direction orthogonal to the array axis and in the whole steering range it exceeds 23 dB. Measurement results of the polarization structure of radiated and scattered pulses with different polarization are presented as well.

  17. Dual polarized receiving steering antenna array for measurement of ultrawideband pulse polarization structure

    Energy Technology Data Exchange (ETDEWEB)

    Balzovsky, E. V.; Buyanov, Yu. I.; Koshelev, V. I., E-mail: koshelev@lhfe.hcei.tsc.ru; Nekrasov, E. S. [Institute of High Current Electronics SB RAS, IHCE SB RAS, Tomsk 634055 (Russian Federation)

    2016-03-15

    To measure simultaneously two orthogonal components of the electromagnetic field of nano- and subnano-second duration, an antenna array has been developed. The antenna elements of the array are the crossed dipoles of dimension 5 × 5 cm. The arms of the dipoles are connected to the active four-pole devices to compensate the frequency response variations of a short dipole in the frequency band ranging from 0.4 to 4 GHz. The dipoles have superimposed phase centers allowing measuring the polarization structure of the field in different directions. The developed antenna array is the linear one containing four elements. The pattern maximum position is controlled by means of the switched ultrawideband true time delay lines. Discrete steering in seven directions in the range from −40° to +40° has been realized. The error at setting the pattern maximum position is less than 4°. The isolation of the polarization exceeds 29 dB in the direction orthogonal to the array axis and in the whole steering range it exceeds 23 dB. Measurement results of the polarization structure of radiated and scattered pulses with different polarization are presented as well.

  18. THE AUGER ENGINEERING RADIO ARRAY

    Directory of Open Access Journals (Sweden)

    Klaus Weidenhaupt

    2013-12-01

    Full Text Available The Auger Engineering Radio Array currently measures MHz radio emission from extensive air showers induced by high energy cosmic rays with 24 self-triggered radio detector stations. Its unique site, embedded into the baseline detectors and extensions of the Pierre Auger Observatory, allows to study air showers in great detail and to calibrate the radio emission. In its final stage AERA will expand to an area of approximately 20km2 to explore the feasibility of the radio-detection technique for future cosmic-ray detectors. The concept and hardware design of AERA as well as strategies to enable self-triggered radio detection are presented. Radio emission mechanisms are discussed based on polarization analysis of the first AERA data.

  19. Synchronous Optical and Radio Polarization Variability in the Blazar OJ287

    Science.gov (United States)

    D'arcangelo, Francesca D.; Marscher, Alan P.; Jorstad, Svetlana G.; Smith, Paul S.; Larionov, Valeri M.; Hagen-Thorn, Vladimir A.; Williams, G. Grant; Gear, Walter K.; Clemens, Dan P.; Sarcia, Domenic; Grabau, Alex; Tollestrup, Eric V.; Buie, Marc W.; Taylor, Brian; Dunham, Edward

    2009-06-01

    We explore the variability and cross-frequency correlation of the flux density and polarization of the blazar OJ287, using imaging at 43 GHz with the Very Long Baseline Array, as well as optical and near-infrared (near-IR) polarimetry. The polarization and flux density in both the optical waveband and the 43 GHz compact core increased by a small amount in late 2005, and increased significantly along with the near-IR polarization and flux density over the course of 10 days in early 2006. Furthermore, the values of the electric vector position angle (EVPA) at the three wavebands are similar. At 43 GHz, the EVPA of the blazar core is perpendicular to the flow of the jet, while the EVPAs of emerging superluminal knots are aligned parallel to the jet axis. The core polarization is that expected if shear aligns the magnetic field at the boundary between flows of disparate velocities within the jet. Using variations in flux density, percentage polarization, and EVPA, we model the inner jet as a spine-sheath system. The model jet contains a turbulent spine of half-width 1fdg2 and maximum Lorentz factor of 16.5, a turbulent sheath with Lorentz factor of 5, and a boundary region of sheared field between the spine and sheath. Transverse shocks propagating along the fast, turbulent spine can explain the superluminal knots. The observed flux density and polarization variations are then compatible with changes in the direction of the inner jet caused by a temporary change in the position of the core if the spine contains wiggles owing to an instability. In addition, we can explain a stable offset of optical and near-IR percentage polarization by a steepening of spectral index with frequency, as supported by the data.

  20. Rainfall measurement using radio links from cellular communication networks

    NARCIS (Netherlands)

    Leijnse, H.; Uijlenhoet, R.; Stricker, J.N.M.

    2007-01-01

    We investigate the potential of radio links such as employed by commercial cellular communication companies to monitor path-averaged rainfall. We present an analysis of data collected using two 38-GHz links during eight rainfall events over a 2-month period (October¿November 2003) during mostly stra

  1. Synchronous Optical and Radio Polarization Variability in the Blazar OJ287

    CERN Document Server

    D'Arcangelo, F D; Jorstad, S G; Smith, P S; Larionov, V M; Hagen-Thorn, V A; Williams, G G; Gear, W K; Clemens, D P; Sarcia, D; Grabau, A; Tollestrup, E V; Buie, M W; Taylor, B; Dunham, E

    2009-01-01

    We explore the variability and cross-frequency correlation of the flux density and polarization of the blazar OJ287, using imaging at 43 GHz with the Very Long Baseline Array, as well as optical and near-infrared polarimetry. The polarization and flux density in both the optical waveband and the 43 GHz compact core increased by a small amount in late 2005, and increased significantly along with the near-IR polarization and flux density over the course of 10 days in early 2006. Furthermore, the values of the electric vector position angle (EVPA) at the three wavebands are similar. At 43 GHz, the EVPA of the blazar core is perpendicular to the flow of the jet, while the EVPAs of emerging superluminal knots are aligned parallel to the jet axis. The core polarization is that expected if shear aligns the magnetic field at the boundary between flows of disparate velocities within the jet. Using variations in flux density, percentage polarization, and EVPA, we model the inner jet as a spine-sheath system. The model ...

  2. Quantum key distribution based on phase encoding and polarization measurement

    CERN Document Server

    Ma, H Q; Zhao, J L; Ma, Hai-Qiang; Wu, Ling-An; Zhao, Jian-Ling

    2007-01-01

    A one-way quantum key distribution scheme based on intrinsically stable Faraday-mirror type Michelson interferometers with four-port polarizing beampslitters has been demonstrated which can compensate for birefringence effects automatically. The encoding is performed with phase modulators, but decoding is accomplished through measurement of the polarization state of Bob's photons. An extinction ratio of about 30dB was maintained for several hours over 50km of fiber at 1310nm without any adjustment to the setup, which shows its good potential for practical systems

  3. The JLab polarization transfer measurements of proton elastic form factor

    Indian Academy of Sciences (India)

    C F Perdrisat; V Punjabi

    2003-11-01

    The ratio of the electric and magnetic proton form factors, /, has been obtained in two Hall A experiments, from measurements of the longitudinal and transverse polarizations of the recoil proton, ℓ and , in the elastic scattering of polarized electrons, $\\overrightarrow{e}p→ e\\overrightarrow{p}$. Together these experiments cover the 2 range of 0.5 to 5.6 GeV2. A new experiment is currently being prepared, to extend the 2 range to 9 GeV2 in Hall C.

  4. Absolute kinematics of radio-source components in the complete S5 polar cap sample. IV. Proper motions of the radio cores over a decade and spectral properties

    CERN Document Server

    Marti-Vidal, I; Marcaide, J M; Guirado, J C; Perez-Torres, M A; Ros, E

    2016-01-01

    We have carried out a high-precision astrometric analysis of two very-long-baseline-interferometry (VLBI) epochs of observation of the 13 extragalactic radio sources in the complete S5 polar cap sample. The VLBI epochs span a time baseline of 10 years and enable us to achieve precisions in the proper motions of the source cores up to a few micro-arcseconds per year. The observations were performed at 14.4 GHz and 43.1 GHz, and enable us to estimate the frequency core-shifts in a subset of sources, for which the spectral-index distributions can be computed. We study the source-position stability by analysing the changes in the relative positions of fiducial source points (the jet cores) over a decade. We find motions of 0.1-0.9 mas among close-by sources between the two epochs, which imply drifts in the jet cores of approximately a few tens of micro-as per year. These results have implications for the standard Active Galactic Nucleus (AGN) jet model (where the core locations are supposed to be stable in time)....

  5. Measuring the cosmic microwave background polarization with POLARBEAR

    Science.gov (United States)

    Barron, Darcy; Polarbear Collaboration

    2015-01-01

    POLARBEAR is a cosmic microwave background (CMB) polarization experiment located in the Atacama desert in Chile. POLARBEAR-1 started observations in 2012, and in 2014, the POLARBEAR team published results from its first season of observations on a small fraction of the sky. These results include the first measurement of a non-zero B-mode polarization angular power spectrum, measured at sub-degree scales where the dominant signal is gravitational lensing of the CMB. We also published a measurement of the large-scale gravitational structure deflection power spectrum derived from CMB polarization alone, which demonstrates a powerful technique that can be used to measure nearly all of the gravitational structure in the universe. Improving these measurements requires precision characterization of the CMB polarization signal over large fractions of the sky, at multiple frequencies. To achieve these goals, POLARBEAR has begun expanding to include an additional two 3.5 meter telescopes with multi-chroic receivers, known as the Simons Array. Phased upgrades to receiver technology will improve sensitivity and capabilities, while continuing a deep survey of 80% of the sky. POLARBEAR-2 is the next receiver that will be installed in 2015 on a new telescope, with a larger area focal plane with dichroic pixels, with bands at 95 GHz and 150 GHz, and a total of 7,588 polarization sensitive antenna-coupled transition edge sensor bolometers. The focal plane is cooled to 250 milliKelvin, and the bolometers will be read-out by SQUID amplifiers with 40x frequency domain multiplexing. The array is designed to have a noise equivalent temperature of 5.7 μK√s.

  6. Preliminary Study on Active Modulation of Polar Mesosphere Summer Echoes with the Radio Propagation in Layered Space Dusty Plasma

    Science.gov (United States)

    Zhou, Shengguo; Li, Hailong; Fu, Luyao; Wang, Maoyan

    2016-06-01

    Radar echoes intensity of polar mesosphere summer echoes (PMSE) is greatly affected by the temperature of dusty plasma and the frequency of electromagnetic wave about the radar. In this paper, a new method is developed to explain the active experiment results of PMSE. The theory of wave propagation in a layered media is used to study the propagation characteristics of an electromagnetic wave at different electron temperatures. The simulation results show that the variation tendency of the reflected power fraction almost agrees with the results observed by radar in the European Incoherent Scatter Scientific Association (EISCAT). The radar echoes intensity of PMSE greatly decreases with the increase of the radio frequency and the enhancement of the electron temperature. supported by National Natural Science Foundation of China (Nos. 41104097 and 41304119) and by the National Key Laboratory of Electromagnetic Environment, China Research Institute of Radiowave Propagation (CRIRP)

  7. On noise treatment in radio measurements of cosmic ray air showers

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, F.G., E-mail: frank.schroeder@kit.edu [Karlsruhe Institute of Technology (KIT) - Campus North, Institut fuer Kernphysik (Germany); Apel, W.D. [Karlsruhe Institute of Technology (KIT) - Campus North, Institut fuer Kernphysik (Germany); Arteaga, J.C. [Karlsruhe Institute of Technology (KIT) - Campus South, Institut fuer Experimentelle Kernphysik (Germany); Asch, T. [Karlsruhe Institute of Technology (KIT) - Campus North, Institut fuer Prozessdatenverarbeitung und Elektronik (Germany); Baehren, L. [Radboud University Nijmegen, Department of Astrophysics (Netherlands); Bekk, K. [Karlsruhe Institute of Technology (KIT) - Campus North, Institut fuer Kernphysik (Germany); Bertaina, M. [Dipartimento di Fisica Generale dell& #x27; Universita, Torino (Italy); Biermann, P.L. [Max-Planck-Institut fuer Radioastronomie, Bonn (Germany); Bluemer, J. [Karlsruhe Institute of Technology (KIT) - Campus North, Institut fuer Kernphysik (Germany); Karlsruhe Institute of Technology (KIT) - Campus South, Institut fuer Experimentelle Kernphysik (Germany); Bozdog, H. [Karlsruhe Institute of Technology (KIT) - Campus North, Institut fuer Kernphysik (Germany); Brancus, I.M. [National Institute of Physics and Nuclear Engineering, Bucharest (Romania); Buchholz, P. [Universitaet Siegen, Fachbereich Physik (Germany); Buitink, S. [Radboud University Nijmegen, Department of Astrophysics (Netherlands); Cantoni, E. [Dipartimento di Fisica Generale dell& #x27; Universita, Torino (Italy); INAF Torino, Istituto di Fisica dello Spazio Interplanetario (Italy); and others

    2012-01-11

    Precise measurements of the radio emission by cosmic ray air showers require an adequate treatment of noise. Unlike to usual experiments in particle physics, where noise always adds to the signal, radio noise can in principle decrease or increase the signal if it interferes by chance destructively or constructively. Consequently, noise cannot simply be subtracted from the signal, and its influence on amplitude and time measurement of radio pulses must be studied with care. First, noise has to be determined consistently with the definition of the radio signal which typically is the maximum field strength of the radio pulse. Second, the average impact of noise on radio pulse measurements at individual antennas is studied for LOPES. It is shown that a correct treatment of noise is especially important at low signal-to-noise ratios: noise can be the dominant source of uncertainty for pulse height and time measurements, and it can systematically flatten the slope of lateral distributions. The presented method can also be transferred to other experiments in radio and acoustic detection of cosmic rays and neutrinos.

  8. Measurement of P_{mu}xi in Polarized Muon Decay

    CERN Document Server

    Jamieson, B; Davydov, Y I; Depommier, P; Doornbos, J; Faszer, W; Fujiwara, M C; Gagliardi, C A; Gaponenko, A N; Gill, D R; Gumplinger, P; Hasinoff, M D; Henderson, R S; Hu, J; Kitching, P; Koetke, D D; MacDonald, J A; MacDonald, R P; Marshall, G M; Mathie, E L; Mischke, R E; Musser, J R; Nozar, M; Olchanski, K; Olin, A; Openshaw, R; Porcelli, T A; Poutissou, J M; Poutissou, R; Quraan, M A; Rodning, N L; Selivanov, V; Sheffer, G; Shin, B; Stanislaus, T D S; Tacik, R; Torokhov, V D; Tribble, R E; Vasilev, M A; Davydov, Yu.I.

    2006-01-01

    The quantity P_{mu}xi, where xi is one of the muon decay parameters and P_{\\mu} is the degree of muon polarization in pion decay, has been measured. The value P_{mu}xi = 1.0003 +- 0.0006 (stat) +- 0.0038 (syst.) was obtained. This result is in agreement with indirect measurements of P_{mu}xi, and confirms their implications for left-right symmetric models and other extensions of the Standard Model.

  9. A Study of Dispersion Compensation of Polarization Multiplexing-Based OFDM-OCDMA for Radio-over-Fiber Transmissions

    Directory of Open Access Journals (Sweden)

    Chih-Ta Yen

    2016-09-01

    Full Text Available Chromatic dispersion from optical fiber is the most important problem that produces temporal skews and destroys the rectangular structure of code patterns in the spectra-amplitude-coding-based optical code-division multiple-access (SAC-OCDMA system. Thus, the balance detection scheme does not work perfectly to cancel multiple access interference (MAI and the system performance will be degraded. Orthogonal frequency-division multiplexing (OFDM is the fastest developing technology in the academic and industrial fields of wireless transmission. In this study, the radio-over-fiber system is realized by integrating OFDM and OCDMA via polarization multiplexing scheme. The electronic dispersion compensation (EDC equalizer element of OFDM integrated with the dispersion compensation fiber (DCF is used in the proposed radio-over-fiber (RoF system, which can efficiently suppress the chromatic dispersion influence in long-haul transmitted distance. A set of length differences for 10 km-long single-mode fiber (SMF and 4 km-long DCF is to verify the compensation scheme by relative equalizer algorithms and constellation diagrams. In the simulation result, the proposed dispersion mechanism successfully compensates the dispersion from SMF and the system performance with dispersion equalizer is highly improved.

  10. A Study of Dispersion Compensation of Polarization Multiplexing-Based OFDM-OCDMA for Radio-over-Fiber Transmissions.

    Science.gov (United States)

    Yen, Chih-Ta; Chen, Wen-Bin

    2016-09-07

    Chromatic dispersion from optical fiber is the most important problem that produces temporal skews and destroys the rectangular structure of code patterns in the spectra-amplitude-coding-based optical code-division multiple-access (SAC-OCDMA) system. Thus, the balance detection scheme does not work perfectly to cancel multiple access interference (MAI) and the system performance will be degraded. Orthogonal frequency-division multiplexing (OFDM) is the fastest developing technology in the academic and industrial fields of wireless transmission. In this study, the radio-over-fiber system is realized by integrating OFDM and OCDMA via polarization multiplexing scheme. The electronic dispersion compensation (EDC) equalizer element of OFDM integrated with the dispersion compensation fiber (DCF) is used in the proposed radio-over-fiber (RoF) system, which can efficiently suppress the chromatic dispersion influence in long-haul transmitted distance. A set of length differences for 10 km-long single-mode fiber (SMF) and 4 km-long DCF is to verify the compensation scheme by relative equalizer algorithms and constellation diagrams. In the simulation result, the proposed dispersion mechanism successfully compensates the dispersion from SMF and the system performance with dispersion equalizer is highly improved.

  11. Digital beacon receiver for ionospheric TEC measurement developed with GNU Radio

    Science.gov (United States)

    Yamamoto, M.

    2008-11-01

    A simple digital receiver named GNU Radio Beacon Receiver (GRBR) was developed for the satellite-ground beacon experiment to measure the ionospheric total electron content (TEC). The open-source software toolkit for the software defined radio, GNU Radio, is utilized to realize the basic function of the receiver and perform fast signal processing. The software is written in Python for a LINUX PC. The open-source hardware called Universal Software Radio Peripheral (USRP), which best matches the GNU Radio, is used as a front-end to acquire the satellite beacon signals of 150 and 400 MHz. The first experiment was successful as results from GRBR showed very good agreement to those from the co-located analog beacon receiver. Detailed design information and software codes are open at the URL http://www.rish.kyoto-u.ac.jp/digitalbeacon/.

  12. ON THE STATISTICAL ANALYSIS OF X-RAY POLARIZATION MEASUREMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Strohmayer, T. E.; Kallman, T. R. [X-ray Astrophysics Lab, Astrophysics Science Division, NASA' s Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2013-08-20

    In many polarimetry applications, including observations in the X-ray band, the measurement of a polarization signal can be reduced to the detection and quantification of a deviation from uniformity of a distribution of measured angles of the form A + Bcos {sup 2}({phi} - {phi}{sub 0}) (0 < {phi} < {pi}). We explore the statistics of such polarization measurements using Monte Carlo simulations and {chi}{sup 2} fitting methods. We compare our results to those derived using the traditional probability density used to characterize polarization measurements and quantify how they deviate as the intrinsic modulation amplitude grows. We derive relations for the number of counts required to reach a given detection level (parameterized by {beta} the ''number of {sigma}'s'' of the measurement) appropriate for measuring the modulation amplitude a by itself (single interesting parameter case) or jointly with the position angle {phi} (two interesting parameters case). We show that for the former case, when the intrinsic amplitude is equal to the well-known minimum detectable polarization, (MDP) it is, on average, detected at the 3{sigma} level. For the latter case, when one requires a joint measurement at the same confidence level, then more counts are needed than what was required to achieve the MDP level. This additional factor is amplitude-dependent, but is Almost-Equal-To 2.2 for intrinsic amplitudes less than about 20%. It decreases slowly with amplitude and is Almost-Equal-To 1.8 when the amplitude is 50%. We find that the position angle uncertainty at 1{sigma} confidence is well described by the relation {sigma}{sub {phi}} = 28. Degree-Sign 5/{beta}.

  13. Radio Frequency (RF) Measurements for Human Detection, Tracking, and Identification

    Science.gov (United States)

    2007-10-01

    of tick bites and the potential for Lyme disease . Insect repellent will be available at the test site and we will ask volunteers to inspect...2003, 150 (4). 6. Chen, Victor C.; Ling, Hao. Time Frequency for Radar Imaging and Signal Analysis; Artech House, 2002. 7. Natecz, Marek ; Rytel... disease that is the direct result of participating in this project (under the provisions of AR 40-38 and AR 70-25). Title of Research Project: Radio

  14. Radio frequency sensing measurements and methods for location classification in wireless networks

    Science.gov (United States)

    Maas, Dustin C.

    The wireless radio channel is typically thought of as a means to move information from transmitter to receiver, but the radio channel can also be used to detect changes in the environment of the radio link. This dissertation is focused on the measurements we can make at the physical layer of wireless networks, and how we can use those measurements to obtain information about the locations of transceivers and people. The first contribution of this work is the development and testing of an open source, 802.11b sounder and receiver, which is capable of decoding packets and using them to estimate the channel impulse response (CIR) of a radio link at a fraction of the cost of traditional channel sounders. This receiver improves on previous implementations by performing optimized matched filtering on the field-programmable gate array (FPGA) of the Universal Software Radio Peripheral (USRP), allowing it to operate at full bandwidth. The second contribution of this work is an extensive experimental evaluation of a technology called location distinction, i.e., the ability to identify changes in radio transceiver position, via CIR measurements. Previous location distinction work has focused on single-input single-output (SISO) radio links. We extend this work to the context of multiple-input multiple-output (MIMO) radio links, and study system design trade-offs which affect the performance of MIMO location distinction. The third contribution of this work introduces the "exploiting radio windows" (ERW) attack, in which an attacker outside of a building surreptitiously uses the transmissions of an otherwise secure wireless network inside of the building to infer location information about people inside the building. This is possible because of the relative transparency of external walls to radio transmissions. The final contribution of this dissertation is a feasibility study for building a rapidly deployable radio tomographic (RTI) imaging system for special operations forces

  15. Primordial gravitational waves measurements and anisotropies of CMB polarization rotation

    Directory of Open Access Journals (Sweden)

    Si-Yu Li

    2015-12-01

    Full Text Available Searching for the signal of primordial gravitational waves in the B-modes (BB power spectrum is one of the key scientific aims of the cosmic microwave background (CMB polarization experiments. However, this could be easily contaminated by several foreground issues, such as the interstellar dust grains and the galactic cyclotron electrons. In this paper we study another mechanism, the cosmic birefringence, which can be introduced by a CPT-violating interaction between CMB photons and an external scalar field. Such kind of interaction could give rise to the rotation of the linear polarization state of CMB photons, and consequently induce the CMB BB power spectrum, which could mimic the signal of primordial gravitational waves at large scales. With the recently released polarization data of BICEP2 and the joint analysis data of BICEP2/Keck Array and Planck, we perform a global fitting analysis on constraining the tensor-to-scalar ratio r by considering the polarization rotation angle [α(nˆ] which can be separated into a background isotropic part [α¯] and a small anisotropic part [Δα(nˆ]. Since the data of BICEP2 and Keck Array experiments have already been corrected by using the “self-calibration” method, here we mainly focus on the effects from the anisotropies of CMB polarization rotation angle. We find that including Δα(nˆ in the analysis could slightly weaken the constraints on the tensor-to-scalar ratio r, when using current CMB polarization measurements. We also simulate the mock CMB data with the BICEP3-like sensitivity. Very interestingly, we find that if the effects of the anisotropic polarization rotation angle could not be taken into account properly in the analysis, the constraints on r will be dramatically biased. This implies that we need to break the degeneracy between the anisotropies of the CMB polarization rotation angle and the CMB primordial tensor perturbations, in order to measure the signal of primordial

  16. MAGNETIC FIELD STRUCTURE OF THE LARGE MAGELLANIC CLOUD FROM FARADAY ROTATION MEASURES OF DIFFUSE POLARIZED EMISSION

    Energy Technology Data Exchange (ETDEWEB)

    Mao, S. A. [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States); McClure-Griffiths, N. M.; McConnell, D. [Australia Telescope National Facility, CSIRO Astronomy and Space Science, Epping, NSW 1710 (Australia); Gaensler, B. M. [Sydney Institute for Astronomy, School of Physics, University of Sydney, Sydney, NSW 2006 (Australia); Haverkorn, M. [Department of Astrophysics, Radboud University, P.O. Box 9010, 6500-GL Nijmegen (Netherlands); Beck, R. [Max-Planck-Institut fuer Radioastronomie, D-53121 Bonn (Germany); Wolleben, M. [Square Kilometre Array South Africa, The Park, Pinelands 7405 (South Africa); Stanimirovic, S. [Department of Astronomy, University of Wisconsin, Madison, WI 53706 (United States); Dickey, J. M. [Physics Department, University of Tasmania, Hobart, TAS 7001 (Australia); Staveley-Smith, L., E-mail: mao@astro.wisc.edu [International Centre for Radio Astronomy Research (ICRAR), The University of Western Australia, Crawley, WA 6009 (Australia)

    2012-11-01

    We present a study of the magnetic field of the Large Magellanic Cloud (LMC), carried out using diffuse polarized synchrotron emission data at 1.4 GHz acquired at the Parkes Radio Telescope and the Australia Telescope Compact Array. The observed diffuse polarized emission is likely to originate above the LMC disk on the near side of the galaxy. Consistent negative rotation measures (RMs) derived from the diffuse emission indicate that the line-of-sight magnetic field in the LMC's near-side halo is directed coherently away from us. In combination with RMs of extragalactic sources that lie behind the galaxy, we show that the LMC's large-scale magnetic field is likely to be of quadrupolar geometry, consistent with the prediction of dynamo theory. On smaller scales, we identify two brightly polarized filaments southeast of the LMC, associated with neutral hydrogen arms. The filaments' magnetic field potentially aligns with the direction toward the Small Magellanic Cloud (SMC). We suggest that tidal interactions between the SMC and the LMC in the past 10{sup 9} years are likely to have shaped the magnetic field in these filaments.

  17. Measuring gravitational lens time delays using low-resolution radio monitoring observations

    CERN Document Server

    Gurkan, G; Koopmans, L V E; Fassnacht, C D; Alba, A Berciano

    2014-01-01

    Obtaining lensing time delay measurements requires long-term monitoring campaigns with a high enough resolution (< 1 arcsec) to separate the multiple images. In the radio, a limited number of high-resolution interferometer arrays make these observations difficult to schedule. To overcome this problem, we propose a technique for measuring gravitational time delays which relies on monitoring the total flux density with low-resolution but high-sensitivity radio telescopes to follow the variation of the brighter image. This is then used to trigger high-resolution observations in optimal numbers which then reveal the variation in the fainter image. We present simulations to assess the efficiency of this method together with a pilot project observing radio lens systems with the Westerbork Synthesis Radio Telescope (WSRT) to trigger Very Large Array (VLA) observations. This new method is promising for measuring time delays because it uses relatively small amounts of time on high-resolution telescopes. This will b...

  18. Radio Weak Lensing Shear Measurement in the Visibility Domain - I. Methodology

    CERN Document Server

    Rivi, Marzia; Makhathini, Sphesihle; Abdalla, Filipe Batoni

    2016-01-01

    The high sensitivity of the new generation of radio telescopes such as the Square Kilometre Array (SKA) will allow cosmological weak lensing measurements at radio wavelengths that are competitive with optical surveys. We present an adaptation to radio data of "lensfit", a method for galaxy shape measurement originally developed and used for optical weak lensing surveys. This likelihood method uses an analytical galaxy model and makes a Bayesian marginalisation of the likelihood over uninteresting parameters. It has the feature of working directly in the visibility domain, which is the natural approach to adopt with radio interferometer data, avoiding systematics introduced by the imaging process. As a proof of concept, we provide results for visibility simulations of individual galaxies with flux density S >= 10muJy at the phase centre of the proposed SKA1-MID baseline configuration, adopting 12 frequency channels in the band 950-1190 MHz. Weak lensing shear measurements from a population of galaxies with rea...

  19. Radio polarization maps of shell-type SNRs - II. Sedov models with evolution of turbulent magnetic field

    Science.gov (United States)

    Petruk, O.; Bandiera, R.; Beshley, V.; Orlando, S.; Miceli, M.

    2017-09-01

    Polarized radio emission has been mapped with great detail in several Galactic supernova remnants (SNRs), but has not yet been exploited to the extent it deserves. We have developed a method to model maps of the Stokes parameters for shell-like SNRs during their Sedov evolution phase. At first, three-dimensional structure of an SNR has been computed, by modelling the distribution of the magnetohydrodynamic parameters and of the accelerated particles. The generation and dissipation of the turbulent component of magnetic field everywhere in SNR are also considered taking into account its interaction with accelerated particles. Then, in order to model the emission, we have used a generalization of the classical synchrotron theory, valid for the case in which the magnetic field has ordered and disordered components. Finally, two-dimensional projected maps have been derived, for different orientations of SNR and of interstellar magnetic field with respect to the observer. An important effect to consider is the Faraday rotation of the polarization planes inside the SNR interior. In this paper, we present details of the model, and describe general properties of the images.

  20. Facility for the (p, n) polarization transfer measurement

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, H. [Tokyo Univ. (Japan). Dept. of Phys.; Okamura, H. [Tokyo Univ. (Japan). Dept. of Phys.; Otsu, H. [Tokyo Univ. (Japan). Dept. of Phys.; Wakasa, T. [Tokyo Univ. (Japan). Dept. of Phys.; Ishida, S. [Tokyo Univ. (Japan). Dept. of Phys.; Sakamoto, N. [Tokyo Univ. (Japan). Dept. of Phys.; Uesaka, T. [Tokyo Univ. (Japan). Dept. of Phys.; Satou, Y. [Tokyo Univ. (Japan). Dept. of Phys.; Fujita, S. [Tokyo Univ. (Japan). Dept. of Phys.; Hatanaka, K. [Research Center for Nuclear Physics, Osaka University, Mihogaoka, Ibaraki 567 (Japan)

    1996-01-21

    We have designed and constructed a facility to measure the complete polarization transfer coefficient D{sub ij} for the (p,n) reaction at intermediate energies. The facility consists of a beam swinger dipole magnet used for angular distribution measurements and a 100 m tunnel for the neutron energy measurement by the time-of-flight method. Typical neutron energy resolution is about 1.85 MeV for 290 MeV neutrons including a contribution of 1 MeV due to the target thickness. The background associated with this tunnel system was carefully investigated and found to be negligibly small. A dipole magnet for the neutron spin rotation is installed in the neutron flight path to measure the longitudinal polarization as well as the induced polarization. The neutron polarimeter which consists of 6 planes of the two-dimensional position-sensitive neutron detectors with a size of 1 m x 1 m x 0.1 m has been constructed. Its effective left-right analyzing power left angle A{sup eff}{sub y} right angle has been calibrated at 194, 290 and 384 MeV. The figure-of-merit value defined by left angle A{sup eff}{sub y} right angle {sup 2} x {epsilon}{sub DS} at 290 MeV is 4.05 x 10{sup -4}, where {epsilon}{sub DS} is the double scattering efficiency. (orig.).

  1. Dynamic phase measurements based on a polarization Michelson interferometer employing a pixelated polarization camera

    Science.gov (United States)

    Serrano-Garcia, David I.; Otani, Yukitoshi

    2017-02-01

    We implemented an interferometric configuration capable of following a phase variation in time. By using a pixelated polarization camera, the system is able to retrieve the phase information instantaneously avoiding the usage of moving components and the necessity of an extra replication method attached at the output of the interferometer. Taking into account the temporal stability obtained from the system, a spatial-temporal phase demodulation algorithm can be implemented on frequency domain for the dynamic phase measurement. Spatial resolution is analyzed experimentally using a USAF pattern, and dynamic phase measurements were done on air and water medium variations due to a jet flame and a living fish as a biological sample, respectively.

  2. Influence of vibration disturbance during polarization coupling measurement of polarization-maintaining fiber.

    Science.gov (United States)

    Guo, Zhenwu; Zhang, Hongxia; Chen, Xinwei; Jia, Dagong; Liu, Tiegen

    2011-07-10

    The principle of the mode cross coupling in polarization-maintaining fiber based on white-light interferometry was analyzed. The method of measuring the polarization mode coupling with a spatial Michelson interferometer was presented. Analysis and emulation were carried out for the vibration disturbance signal caused by the mechanical scanning and the influence the vibration imposed on the judgment of coupling intensity. The interference signal envelope is extracted by a Hilbert transform and fitted by a Gaussian least-squares method under the different scanning speed. It is indicated that the detection accuracy varies with the vibration amplitude, which varies with scanning speed. The best scanning speed of the system should be from 0.7 mm/s to 0.9 mm/s to achieve the minimum detection error.

  3. The Sky Polarization Observatory (SPOrt): a project to measure the diffused sky polarization from the International Space Station Alpha (ISSA)

    Science.gov (United States)

    Cortiglioni, S.

    1999-07-01

    The Sky Polarization Observatory (SPOrt), a project to measure the diffused sky polarization in the frequency range of 22-90 GHz from the International Space Station, is described in its current configuration. Some preliminary considerations about the general topic of polarization in radiometric observations are made, in order to introduce the importance of polarimetric measurements in the more general context of Cosmic Microwave Background observations. The International Space Station is also introduced as a quite good opportunity to address such problematics.

  4. Precise measurement of parity violation in polarized muon decay

    CERN Document Server

    Bueno, J F; Davydov, Yu I; Depommier, P; Faszer, W; Gagliardi, C A; Gaponenko, A; Gill, D R; Grossheim, A; Gumplinger, P; Hasinoff, M D; Henderson, R S; Hillairet, A; Hu, J; Koetke, D D; MacDonald, R P; Marshall, G M; Mathie, E L; Mischke, R E; Olchanski, K; Olin, A; Openshaw, R; Poutissou, J -M; Poutissou, R; Selivanov, V; Sheffer, G; Shin, B; Stanislaus, T D S; Tacik, R; Tribble, R E

    2011-01-01

    We present a new high precision measurement of parity violation in the weak interaction, using polarized muon decay. The TWIST collaboration has measured $P_\\mu^\\pi \\xi$, where $P_\\mu^\\pi$ is the polarization of the muon in pion decay and $\\xi$ describes the intrinsic asymmetry in muon decay. We find $P_\\mu^\\pi \\xi = 1.00084 \\pm 0.00029\\,(\\textrm{stat.})_{-0.00063}^{+0.00165}\\,(\\textrm{syst.})$, in good agreement with the standard model prediction of $P_\\mu^\\pi=\\xi=1$. Our result is a factor of seven more precise than the pre-TWIST value, setting new limits in left-right symmetric electroweak extensions to the standard model.

  5. Emittance measurements for the Illinois/CEBAF polarized electron source

    Energy Technology Data Exchange (ETDEWEB)

    Dunham, B.M.; Cardman, L.S. [Illinois Univ., Urbana, IL (United States); Sinclair, C.K. [Continuous Electron Beam Accelerator Facility, Newport News, VA (United States)

    1995-01-01

    The transverse thermal properties of the electrons photoemitted from GaAs determine the intrinsic beam emittance, an important quantity in applications such as polarized electron sources and high-brightness sources. In this paper, emittance measurements using the Illinois/CEBAF polarized electron source are described. The emittance was measured as a function of both the laser beam spot size and laser wavelength at low currents. The data was used to infer the transverse thermal energy of the electrons photoemitted from GaAs for wavelengths between 514 and 840 nm. Near the bandgap the transverse energy is {approximately}34 meV, a factor of 3 lower than that of the beam from a typical thermionic electron gun. 8 refs., 2 figs.

  6. Muon polarization in the MEG experiment: predictions and measurements

    CERN Document Server

    Baldini, A M; Baracchini, E; Bemporad, C; Berg, F; Biasotti, M; Boca, G; Cattaneo, P W; Cavoto, G; Cei, F; Chiarello, G; Chiri, C; De Bari, A; De Gerone, M; DÓnofrio, A; Dussoni, S; Fujii, Y; Galli, L; Gatti, F; Grancagnolo, F; Grassi, M; Graziosi, A; Grigoriev, D N; Haruyama, T; Hildebrandt, M; Hodge, Z; Ieki, K; Ignatov, F; Iwamoto, T; Kaneko, D; Kang, T I; Kettle, P R; Khazin, B I; Khomutov, N; Korenchenko, A; Kravchuk, N; Lim, G M A; Mihara, S; Molzon, W; Mori, T; Mtchedlishvili, A; Nakaura, S; Nicolò, D; Nishiguchi, H; Nishimura, M; Ogawa, S; Ootani, W; Panareo, M; Papa, A; Pepino, A; Piredda, G; Pizzigoni, G; Popov, A; Renga, F; Ripiccini, E; Ritt, S; Rossella, M; Rutar, G; Sawada, R; Sergiampietri, F; Signorelli, G; Tassielli, G; Tenchini, F; Uchiyama, Y; Venturini, M; Voena, C; Yamamoto, A; Yoshida, K; You, Z; Yudin, Y V

    2015-01-01

    The MEG experiment makes use of one of the world's most intense low energy muon beams, in order to search for the lepton flavour violating process $\\mu^{+} \\rightarrow {\\rm e}^{+} \\gamma$. We determined the residual beam polarization at the thin stopping target, by measuring the asymmetry of the angular distribution of Michel decay positrons as a function of energy. The initial muon beam polarization at the production is predicted to be $P_{\\mu} = -1$ by the Standard Model (SM) with massless neutrinos. We estimated our residual muon polarization to be $P_{\\mu} = -0.85 \\pm 0.03 ~ {\\rm (stat)} ~ { }^{+ 0.04}_{-0.05} ~ {\\rm (syst)}$ at the stopping target, which is consistent with the SM predictions when the depolarizing effects occurring during the muon production, propagation and moderation in the target are taken into account. The knowledge of beam polarization is of fundamental importance in order to model the background of our ${\\megsign}$ search induced by the muon radiative decay: $\\mu^{+} \\rightarrow {\\r...

  7. Muon polarization in the MEG experiment: predictions and measurements

    Energy Technology Data Exchange (ETDEWEB)

    Baldini, A.M.; Dussoni, S.; Galli, L.; Grassi, M.; Sergiampietri, F.; Signorelli, G. [Pisa Univ. (Italy); INFN Sezione di Pisa, Pisa (Italy); Bao, Y.; Hildebrandt, M.; Kettle, P.R.; Mtchedlishvili, A.; Papa, A.; Ritt, S. [Paul Scherrer Institut PSI, Villigen (Switzerland); Baracchini, E. [University of Tokyo, ICEPP, Tokyo (Japan); INFN, Laboratori Nazionali di Frascati, Rome (Italy); Bemporad, C.; Cei, F.; D' Onofrio, A.; Nicolo, D.; Tenchini, F. [INFN Sezione di Pisa, Pisa (Italy); Pisa Univ., Dipartimento di Fisica, Pisa (Italy); Berg, F.; Hodge, Z.; Rutar, G. [Paul Scherrer Institut PSI, Villigen (Switzerland); Swiss Federal Institute of Technology ETH, Zurich (Switzerland); Biasotti, M.; Gatti, F.; Pizzigoni, G. [INFN Sezione di Genova, Genova (Italy); Genova Univ., Dipartimento di Fisica, Genova (Italy); Boca, G.; De Bari, A. [INFN Sezione di Pavia, Pavia (Italy); Pavia Univ., Dipartimento di Fisica, Pavia (Italy); Cattaneo, P.W.; Rossella, M. [Pavia Univ. (Italy); INFN Sezione di Pavia, Pavia (Italy); Cavoto, G.; Piredda, G.; Renga, F.; Voena, C. [Univ. ' ' Sapienza' ' , Rome (Italy); INFN Sezione di Roma, Rome (Italy); Chiarello, G.; Panareo, M.; Pepino, A. [INFN Sezione di Lecce, Lecce (Italy); Univ. del Salento, Dipartimento di Matematica e Fisica, Lecce (Italy); Chiri, C.; Grancagnolo, F.; Tassielli, G.F. [Univ. del Salento (Italy); INFN Sezione di Lecce, Lecce (Italy); De Gerone, M. [Genova Univ. (Italy); INFN Sezione di Genova, Genova (Italy); Fujii, Y.; Iwamoto, T.; Kaneko, D.; Mori, Toshinori; Nakaura, S.; Nishimura, M.; Ogawa, S.; Ootani, W.; Sawada, R.; Uchiyama, Y.; Yoshida, K. [University of Tokyo, ICEPP, Tokyo (Japan); Graziosi, A.; Ripiccini, E. [INFN Sezione di Roma, Rome (Italy); Univ. ' ' Sapienza' ' , Dipartimento di Fisica, Rome (Italy); Grigoriev, D.N. [Budker Institute of Nuclear Physics of Siberian Branch of Russian Academy of Sciences, Novosibirsk (Russian Federation); Novosibirsk State Technical University, Novosibirsk (Russian Federation); Novosibirsk State University, Novosibirsk (Russian Federation); Haruyama, T.; Mihara, S.; Nishiguchi, H.; Yamamoto, A. [KEK, High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan); Ieki, K. [Paul Scherrer Institut PSI, Villigen (Switzerland); University of Tokyo, ICEPP, Tokyo (Japan); Ignatov, F.; Khazin, B.I.; Popov, A.; Yudin, Yu.V. [Budker Institute of Nuclear Physics of Siberian Branch of Russian Academy of Sciences, Novosibirsk (Russian Federation); Novosibirsk State University, Novosibirsk (Russian Federation); Kang, T.I.; Lim, G.M.A.; Molzon, W.; You, Z. [University of California, Irvine, CA (United States); Khomutov, N.; Korenchenko, A.; Kravchuk, N. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Venturini, M. [Pisa Univ. (Italy); INFN Sezione di Pisa, Pisa (Italy); Scuola Normale Superiore, Pisa (Italy); Collaboration: The MEG Collaboration

    2016-04-15

    The MEG experiment makes use of one of the world's most intense low energy muon beams, in order to search for the lepton flavour violating process μ{sup +} → e{sup +}γ. We determined the residual beam polarization at the thin stopping target, by measuring the asymmetry of the angular distribution of Michel decay positrons as a function of energy. The initial muon beam polarization at the production is predicted to be P{sub μ} = -1 by the Standard Model (SM) with massless neutrinos. We estimated our residual muon polarization to be P{sub μ} =.0.86 ± 0.02 (stat){sub -0.06}{sup +0.05} (syst) at the stopping target, which is consistent with the SM predictions when the depolarizing effects occurring during the muon production, propagation and moderation in the target are taken into account. The knowledge of beam polarization is of fundamental importance in order to model the background of our μ{sup +} → e{sup +}γ search induced by the muon radiative decay: μ{sup +} → e{sup +} anti ν{sub μ}ν{sub e}γ. (orig.)

  8. Measuring vacuum polarization with high-power lasers

    Institute of Scientific and Technical Information of China (English)

    B.King; T.Heinzl

    2016-01-01

    When exposed to intense electromagnetic fields, the quantum vacuum is expected to exhibit properties of a polarizable medium akin to a weakly nonlinear dielectric material. Various schemes have been proposed to measure such vacuum polarization effects using a combination of high- power lasers. Motivated by several planned experiments, we provide an overview of experimental signatures that have been suggested to confirm this prediction of quantum electrodynamics of real photon–photon scattering.

  9. Absolute kinematics of radio-source components in the complete S5 polar cap sample. IV. Proper motions of the radio cores over a decade and spectral properties

    Science.gov (United States)

    Martí-Vidal, I.; Abellán, F. J.; Marcaide, J. M.; Guirado, J. C.; Pérez-Torres, M. A.; Ros, E.

    2016-11-01

    We have carried out a high-precision astrometric analysis of two very-long-baseline-interferometry (VLBI) epochs of observation of the 13 extragalactic radio sources in the complete S5 polar cap sample. The VLBI epochs span a time baseline of ten years and enable us to achieve precisions in the proper motions of the source cores up to a few micro-arcseconds per year. The observations were performed at 14.4 GHz and 43.1 GHz, and enable us to estimate the frequency core-shifts in a subset of sources, for which the spectral-index distributions can be computed. We study the source-position stability by analysing the changes in the relative positions of fiducial source points (the jet cores) over a decade. We find motions of 0.1-0.9 mas among close-by sources between the two epochs, which imply drifts in the jet cores of approximately a few tens of μas per year. These results have implications for the standard Active Galactic Nucleus (AGN) jet model (where the core locations are supposed to be stable in time). For one of our sources, 0615+820, the morphological and spectral properties in year 2010, as well as the relative astrometry between years 2000 and 2010, suggest the possibility of either a strong parsec-scale interaction of the AGN jet with the ISM, a gravitational lens with 1 mas diameter, or a resolved massive binary black hole. Reduced images as FITS files are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/596/A27

  10. Probing magnetar magnetosphere through X-ray polarization measurements

    Science.gov (United States)

    Taverna, R.; Muleri, F.; Turolla, R.; Soffitta, P.; Fabiani, S.; Nobili, L.

    2014-02-01

    The study of magnetars is of particular relevance since these objects are the only laboratories where the physics in ultra-strong magnetic fields can be directly tested. Until now, spectroscopic and timing measurements at X-ray energies in soft gamma repeaters and anomalous X-ray pulsars (AXPs) have been the main source of information about the physical properties of a magnetar and of its magnetosphere. Spectral fitting in the ˜0.5-10 keV range allowed us to validate the `twisted magnetosphere' model, probing the structure of the external field and estimating the density and velocity of the magnetospheric currents. Spectroscopy alone, however, may fail in disambiguating the two key parameters governing magnetospheric scattering (the charge velocity and the twist angle) and is quite insensitive to the source geometry. X-ray polarimetry, on the other hand, can provide a quantum leap in the field by adding two extra observables, the linear polarization degree and the polarization angle. Using the bright AXP 1RXS J170849.0-400910 as a template, we show that phase-resolved polarimetric measurements can unambiguously determine the model parameters, even with a small X-ray polarimetry mission carrying modern photoelectric detectors and existing X-ray optics. We also show that polarimetric measurements can pinpoint vacuum polarization effects and thus provide indirect evidence for ultra-strong magnetic fields.

  11. Radio emission in air showers measured by LOPES-10 in concidence with KASCADE-Grande observations

    Energy Technology Data Exchange (ETDEWEB)

    Badea, A.F.; Apel, W.D.; Asch, T. (and others)

    2006-05-15

    Data taken during half a year of operation of 10 LOPES antennas (LOPES-10), triggered by EAS observed with KASCADE-Grande have been analysed. We report about the analysis of correlations of radio signals measured by LOPES-10 with extensive air shower events reconstructed by KASCADE-Grande, including shower cores at large distances. The efficiency of detecting radio signals induced by air showers up to distances of 700m from the shower axis has been investigated. The results are discussed with special emphasis on the effects of the reconstruction accuracy for shower core and arrival direction on the coherence of the measured radio signal. In addition, the correlations of the radio pulse amplitude with the primary cosmic ray energy and with the lateral distance from the shower core are studied. (Orig.)

  12. Polarization measurements through space-to-ground atmospheric propagation paths by using a highly polarized laser source in space.

    Science.gov (United States)

    Toyoshima, Morio; Takenaka, Hideki; Shoji, Yozo; Takayama, Yoshihisa; Koyama, Yoshisada; Kunimori, Hiroo

    2009-12-07

    The polarization characteristics of an artificial laser source in space were measured through space-to-ground atmospheric transmission paths. An existing Japanese laser communication satellite and optical ground station were used to measure Stokes parameters and the degree of polarization of the laser beam transmitted from the satellite. As a result, the polarization was preserved within an rms error of 1.6 degrees, and the degree of polarization was 99.4+/-4.4% through the space-to-ground atmosphere. These results contribute to the link estimation for quantum key distribution via space and provide the potential for enhancements in quantum cryptography worldwide in the future.

  13. Measuring CMB polarization from ISS: the SPOrt experiment

    Energy Technology Data Exchange (ETDEWEB)

    Colombo, L.P.L. [Physics Dep. ' G. Occhialini' , Universita di Milano-Bicocca and INFN sezione di Milano-Bicocca, Piazza della Scienza, 3 I-20126 Milan (Italy)

    2004-09-01

    The SPOrt (Sky Polarization Observatory) experiment aims to measure CMBP (cosmic microwave background polarization) on about 80% of the sky from space. Selected by ESA to fly on board the ISS in 2006, it is funded by the Italian Space Agency (ASI). As shown also by the recent WMAP release, CMBP data, besides of removing various degeneracies among cosmological parameters, provided new and important information on the cosmic opacity {tau} and, therefore, on very early cosmic objects which reionized the world at z {approx} 15. Most such information is obtained from low-l spectral components, that SPOrt, with its HPBW resolution of 7 degrees will explore with a high level of sensitivity. The 4 polarimeters of SPOrt work at 22, 32 and (2x) 90 GHz. At lower frequencies they will provide a (nearly) all-sky survey of Galactic synchrotron polarized emission, while data at the higher frequency will measure the CMBP signal. Correlating SPOrt with anisotropy data, by other experiments, shall therefore provide significant cosmological information. We performed a number of simulations of SPOrt performance, aimed to determine how far {tau} and/or other parameter(s) concerning reionization are constrained by the expected data. We also considered a possible interplay between reionization histories and Dark Energy nature. Besides of information on technological developments for systematics reduction, long term stability and observing time efficiency, we report here recent outputs on the expected SPOrt performance in constraining cosmological models.

  14. A measurement of τ polarization in Z 0 decays

    Science.gov (United States)

    Adriani, O.; Aguilar-Benitez, M.; Ahlen, S.; Akbari, H.; Alcaraz, J.; Aloisio, A.; Alverson, G.; Alviggi, M. G.; Ambrosi, G.; An, Q.; Anderhub, H.; Anderson, A. L.; Andreev, V. P.; Angelov, T.; Antonov, L.; Antreasyan, D.; Arce, P.; Arefiev, A.; Atamanchuk, A.; Azemoon, T.; Aziz, T.; Baba, P. V. K. S.; Bagnaia, P.; Bakken, J. A.; Baksay, L.; Ball, R. C.; Banerjee, S.; Bao, J.; Barillère, R.; Barone, L.; Baschirotto, A.; Battiston, R.; Bay, A.; Becattini, F.; Becker, U.; Behner, F.; Behrens, J.; Beingessner, S.; Bencze, Gy. L.; Berdugo, J.; Berges, P.; Bertucci, B.; Betev, B. L.; Biasini, M.; Biland, A.; Bilei, G. M.; Bizzarri, R.; Blaising, J. J.; Blumenfeld, B.; Bobbink, G. J.; Bocciolini, M.; Bock, R.; Böhm, A.; Borgia, B.; Boseti, M.; Bourilkov, D.; Bourquin, M.; Boutigny, D.; Bouwens, B.; Brambilla, E.; Branson, J. G.; Brock, I. C.; Brooks, M.; Buisson, C.; Bujak, A.; Burger, J. D.; Burger, W. J.; Burq, J. P.; Busenitz, J.; Cai, X. D.; Capell, M.; Caria, M.; Carlino, G.; Carminati, F.; Cartacci, A. M.; Castello, R.; Cerrada, M.; Cesaroni, F.; Chang, Y. H.; Chaturvedi, U. K.; Chemarin, M.; Chen, A.; Chen, C.; Chen, G. M.; Chen, H. F.; Chen, H. S.; Chen, J.; Chen, M.; Chen, M. L.; Chen, W. Y.; Chiefari, G.; Chien, C. Y.; Chmeissani, M.; Choi, M. T.; Chung, S.; Civinini, C.; Clare, I.; Clare, R.; Coan, T. E.; Cohn, H. O.; Coignet, G.; Colino, N.; Contin, A.; Crijns, F.; Cui, X. T.; Cui, X. Y.; Dai, T. S.; D'Alessandro, R.; de Asmundis, R.; Degré, A.; Deiters, K.; Dénes, E.; Denes, P.; DeNotaristefani, F.; Dhina, M.; DiBitonto, D.; Diemoz, M.; Dimitrov, H. R.; Dionisi, C.; Dova, M. T.; Drago, E.; Driever, T.; Duchesneau, D.; Duinker, P.; Duran, I.; Easo, S.; El Mamouni, H.; Engler, A.; Eppling, F. J.; Erné, F. C.; Extermann, P.; Fabbretti, R.; Fabre, M.; Falciano, S.; Fan, S. J.; Fackler, O.; Fay, J.; Felcini, M.; Ferguson, T.; Fernandez, D.; Fernandez, G.; Ferroni, F.; Fesefeldt, H.; Fiandrini, E.; Field, J.; Filthaut, F.; Finocchiaro, G.; Fisher, P. H.; Forconi, G.; Foreman, T.; Freudenreich, K.; Friebel, W.; Fukushima, M.; Gailloud, M.; Galaktionov, Yu.; Gallo, E.; Ganguli, S. N.; Garcia-Abia, P.; Gau, S. S.; Gele, D.; Gentile, S.; Goldfarb, S.; Gong, Z. F.; Gonzalez, E.; Göttlicher, P.; Gougas, A.; Goujon, D.; Gratta, G.; Grinnell, C.; Gruenewald, M.; Gu, C.; Guanziroli, M.; Guo, J. K.; Gupta, V. K.; Gurtu, A.; Gustafson, H. R.; Gutay, L. J.; Hangarter, K.; Hasan, A.; Hauschildt, D.; He, C. F.; Hebbeker, T.; Hebert, M.; Herten, G.; Herten, U.; Hervé, A.; Hilgers, K.; Hofer, H.; Hoorani, H.; Hu, G.; Hu, G. Q.; Ille, B.; Ilyas, M. M.; Innocente, V.; Janssen, H.; Jezequel, S.; Jin, B. N.; Jones, L. W.; Kasser, A.; Khan, R. A.; Kamyshkov, Yu.; Kapinos, P.; Kapustinsky, J. S.; Karyotakis, Y.; Kaur, M.; Khokar, S.; Kienzle-Focacci, M. N.; Kim, J. K.; Kim, S. C.; Kim, Y. G.; Kinnison, W. W.; Kirkby, D.; Kirsch, S.; Kittel, W.; Klimentov, A.; König, A. C.; Koffeman, E.; Kornadt, O.; Koutsenko, V.; Koulbardis, A.; Kraemer, R. W.; Kramer, T.; Krastev, V. R.; Krenz, W.; Krivshich, A.; Kuijten, H.; Kumar, K. S.; Kunin, A.; Landi, G.; Lanske, D.; Lanzano, S.; Lebrun, P.; Lecomte, P.; Lecoq, P.; Le Coultre, P.; Lee, D. M.; Leedom, I.; Le Goff, J. M.; Leiste, R.; Lenti, M.; Leonardi, E.; Lettry, J.; Leytens, X.; Li, C.; Li, H. T.; Li, P. J.; Li, X. G.; Liao, J. Y.; Lin, W. T.; Lin, Z. Y.; Linde, F. L.; Lindemann, B.; Linnhofer, D.; Lista, L.; Liu, Y.; Lohmann, W.; Longo, E.; Lu, Y. S.; Lubbers, J. M.; Lübelsmeyer, K.; Luci, C.; Luckey, D.; Ludovici, L.; Luminari, L.; Lustermann, W.; Ma, J. M.; Ma, W. G.; MacDermott, M.; Malhotra, P. K.; Malik, R.; Malinin, A.; Ma˜na, C.; Mao, D. N.; Mao, Y. F.; Maolinbay, M.; Marchesini, P.; Marion, F.; Marin, A.; Martin, J. P.; Martinez-Laso, L.; Marzano, F.; Massaro, G. G. G.; Matsuda, T.; Mazumdar, K.; McBride, P.; McMahon, T.; McNally, D.; Meinholz, Th.; Merk, M.; Merola, L.; Meschini, M.; Metzger, W. J.; Mi, Y.; Mills, G. B.; Mir, Y.; Mirabelli, G.; Mnich, J.; Möller, M.; Monteleoni, B.; Morand, R.; Morganti, S.; Moulai, N. E.; Mount, R.; Müller, S.; Nadtochy, A.; Nagy, E.; Napolitano, M.; Newman, H.; Neyer, C.; Niaz, M. A.; Nippe, A.; Nowak, H.; Organtini, G.; Pandoulas, D.; Paoletti, S.; Paolucci, P.; Passaleva, G.; Patricelli, S.; Paul, T.; Pauluzzi, M.; Pauss, F.; Pei, Y. J.; Pensotti, S.; Perret-Gallix, D.; Perrier, J.; Pevsner, A.; Piccolo, D.; Peiri, M.; Piroué, P. A.; Plasil, F.; Plyaskin, V.; Pohl, M.; Pojidaev, V.; Produit, N.; Qian, J. M.; Qureshi, K. N.; Raghavan, R.; Rahal-Callot, G.; Rancoita, P. G.; Rattaggi, M.; Raven, G.; Razis, P.; Read, K.; Ren, D.; Ren, Z.; Rescigno, M.; Reucroft, S.; Ricker, A.; Riemann, S.; Riemers, W.; Rind, O.; Rizvi, H. A.; Rodriguez, F. J.; Roe, B. P.; Röhner, M.; Röhner, S.; Romero, L.; Rose, J.; Rosier-Lees, S.; Rosmalen, R.; Rosselet, Ph.; Rubbia, A.; Rubio, J. A.; Rykaczewski, H.; Sachwitz, M.; Sajan, E.; Salicio, J.; Salicio, J. M.; Sanders, G. S.; Santocchia, A.; Sarakinos, M. S.; Sartorelli, G.; Sassowsky, M.; Sauvage, G.; Schegelsky, V.; Schmiemann, K.; Schmitz, D.; Schmitz, P.; Schneegans, M.; Schopper, H.; Schotanus, D. J.; Shotkin, S.; Schreiber, H. J.; Shukla, J.; Schulte, R.; Schulte, S.; Schultze, K.; Schütte, J.; Schwenke, J.; Schwering, G.; Sciacca, C.; Scott, I.; Sehgal, R.; Seiler, P. G.; Sens, J. C.; Servoli, L.; Sheer, I.; Shen, D. Z.; Shevchenko, S.; Shi, X. R.; Shumilov, E.; Shoutko, V.; Soderstrom, E.; Son, D.; Sopczak, A.; Spartiotis, C.; Spickermann, T.; Spillantini, P.; Starosta, R.; Steuer, M.; Stickland, D. P.; Sticozzi, F.; Stone, H.; Strauch, K.; Stringfellow, B. C.; Sudhakar, K.; Sultanov, G.; Sumner, R. L.; Sun, L. Z.; Suter, H.; Sutton, R. B.; Swain, J. D.; Syed, A. A.; Tang, X. W.; Taylor, L.; Terzi, G.; Timmermans, C.; Ting, Samuel C. C.; Ting, S. M.; Tonutti, M.; Tonwar, S. C.; Tóth, J.; Tsaregorodtsev, A.; Tsipolitis, G.; Tully, C.; Tung, K. L.; Ulbricht, J.; Urbán, L.; Uwer, U.; Valente, E.; Van de Walle, R. T.; Vetlitsky, I.; Viertel, G.; Vikas, P.; Vikas, U.; Vivargent, M.; Vogel, H.; Vogt, H.; Vorobiev, I.; Vorobyov, A. A.; Vuilleumier, L.; Wadhwa, M.; Wallraff, W.; Wang, C. R.; Wang, G. H.; Wang, J. H.; Wang, Q. F.; Wang, X. L.; Wang, Y. F.; Wang, Z. M.; Weber, A.; Weber, J.; Weill, R.; Wenaus, T. J.; Wenninger, J.; White, M.; Willmott, C.; Wittgenstein, F.; Wright, D.; Wu, R. J.; Wu, S. X.; Wu, Y. G.; Wysłouch, B.; Xie, Y. Y.; Xu, Y. D.; Xu, Z. Z.; Xue, Z. L.; Yan, D. S.; Yan, X. J.; Yang, B. Z.; Yang, C. G.; Yang, G.; Yang, K. S.; Yang, Q. Y.; Yang, Z. Q.; Ye, C. H.; Ye, J. B.; Ye, Q.; Yeh, S. C.; Yin, Z. W.; You, J. M.; Yunus, N.; Yzerman, M.; Zaccardelli, C.; Zemp, P.; Zeng, M.; Zeng, Y.; Zhang, D. H.; Zhang, Z. P.; Zhou, B.; Zhou, J. F.; Zhu, R. Y.; Zhuang, H. L.; Zichichi, A.; van der Zwaan, B. C. C.; L3 Collaboration

    1992-11-01

    The polarization of τ leptons produced in e +e - → τ+τ-( γ) is measured using a sample of 8977 τ+τ- pairs collected near the peak of the Z 0 resonance. A polarization of -0.132±0.026(stat)±0.021(syst.) is determined. This corresponds to a ratio of the vector to the axial-vector coupling constants of the τ lepton to the weak neutral current of gVτ/ gAeffτ = 0.067±0.017. This leads to a value of the effective sin 2θw at the Z 0 resonance of sin2θeff = 0.2326±0.0043.

  15. Towards polarization measurements of laser-accelerated helium-3 ions

    Energy Technology Data Exchange (ETDEWEB)

    Engin, Ilhan

    2015-08-28

    In the framework of this thesis, preparatory investigations for the spin-polarization measurement of {sup 3}He ions from laser-induced plasmas have been performed. Therefore, experiments aiming at an efficient laser-induced ion acceleration out of a {sup 4}He gas target were carried out at two high-intensity laser facilities: the Arcturus laser at Heinrich-Heine-Universitaet Duesseldorf as well as PHELIX at GSI Darmstadt. The scientific goal of both experiments was to investigate the ion-acceleration process in underdense plasmas by measuring the ion energy spectra and the angular distribution of the ion signal around the gas-jet target. Laser-accelerated MeV-He-ions could successfully be detected. The main acceleration direction at large angles with regard to the laser propagation direction was determined. In a second step, unpolarized {sup 3}He gas was attached in order to cross-check the experimental results with those of {sup 4}He. With the help of the achieved ion yield data, the expected rates of the fusion reaction D({sup 3}He,p){sup 4}He in the polarized case have been estimated: the information regarding the fusion proton yield from this nuclear reaction allows an experimentally based estimation for future experiments with pre-polarized {sup 3}He gas as plasma target. The experimental data is in line with supporting Particle-in-Cell (PIC) simulations performed on the Juelich supercomputers. For this purpose, the simulated target was defined as a neutral gas. The use of pre-polarized {sup 3}He gas demands a special preparation of a polarized {sup 3}He target for laser-acceleration experiments. This layout includes an (external) homogeneous magnetic holding field (field strength of ∝1.4 mT) for storing the pre-polarized gas for long time durations inside the PHELIX target chamber. For this purpose, a precise Halbach array consisting of horizontally arranged rings with built-in permanent magnets had to be designed, optimized, and constructed to deliver high

  16. Performance and retention of lightweight satellite radio tags applied to the ears of polar bears (Ursus maritimus)

    Science.gov (United States)

    Wiig, Øystein; Born, Erik W.; Laidre, Kristin L.; Dietz, Rune; Jensen, Mikkel Villum; Durner, George M.; Pagano, Anthony M.; Regehr, Eric V.; St. Martin, Michelle; Atkinson, Stephen N.; Dyck, Markus

    2017-01-01

    BackgroundSatellite telemetry studies provide information that is critical to the conservation and management of species affected by ecological change. Here we report on the performance and retention of two types (SPOT-227 and SPOT-305A) of ear-mounted Argos-linked satellite transmitters (i.e., platform transmitter terminal, or PTT) deployed on free-ranging polar bears in Eastern Greenland, Baffin Bay, Kane Basin, the southern Beaufort Sea, and the Chukchi Sea during 2007–2013.ResultsTransmissions from 142 out of 145 PTTs deployed on polar bears were received for an average of 69.3 days. The average functional longevity, defined as the number of days they transmitted while still attached to polar bears, for SPOT-227 was 56.8 days and for SPOT-305A was 48.6 days. Thirty-four of the 142 (24%) PTTs showed signs of being detached before they stopped transmitting, indicating that tag loss was an important aspect of tag failure. Furthermore, 10 of 26 (38%) bears that were re-observed following application of a PTT had a split ear pinna, suggesting that some transmitters were detached by force. All six PTTs that were still on bears upon recapture had lost the antenna, which indicates that antenna breakage was a significant contributor to PTT failure. Finally, only nine of the 142 (6%) PTTs—three of which were still attached to bears—had a final voltage reading close to the value indicating battery exhaustion. This suggests that battery exhaustion was not a major factor in tag performance.ConclusionsThe average functional longevity of approximately 2 months for ear-mounted PTTs (this study) is poor compared to PTT collars fitted to adult female polar bears, which can last for several years. Early failure of the ear-mounted PTTs appeared to be caused primarily by detachment from the ear or antenna breakage. We suggest that much smaller and lighter ear-mounted transmitters are necessary to reduce the risk of tissue irritation, tissue damage, and tag detachment, and

  17. Polarizers, optical bridges and Sagnac interferometers for nanoradian polarization rotation measurements

    CERN Document Server

    Rowe, Alistair; Dilasser, Guillaume; Lassailly, Yves; Peretti, Jacques

    2016-01-01

    The ability to measure nanoradian polarization rotations, $\\theta_F$, in the photon shot noise limit is investigated for partially crossed polarizers (PCP), a static Sagnac interferometer and an optical bridge, each of which can in principal be used in this limit with equivalent figures-of-merit (FOM). In practice a common mode source noise rejection ratio of $1/2\\theta_F$ obtained with the bridge enables this configuration to operate in the photon shot noise limit even at high light intensities. This is demonstrated for a rotation angle of 38 $\\mu$rad, obtained via the Faraday effect in a terbium gallium garnet (TGG), where the experimentally measured FOM in units of $10^{-11}$/photon are 2 (PCP), 1 (Sagnac), and 3.5 (bridge). The superior performance of the bridge is illustrated via the measurement of a 3 nrad rotation occuring when the TGG is placed in an axial magnetic field of 0.9 nT. While the Sagnac is shown to be functionally equivalent to the PCP in terms of the FOM, unlike the PCP it is able to disc...

  18. Calibrating 100 Years of Polar Faculae Measurements: Implications for the Evolution of the Heliospheric Magnetic Field

    CERN Document Server

    Muñoz-Jaramillo, Andrés; Zhang, Jie; DeLuca, Edward E; 10.1088/0004-637X/753/2/146

    2013-01-01

    Although the Sun's polar magnetic fields are thought to provide important clues for understanding the 11-year sunspot cycle, including the observed variations of its amplitude and period, the current database of high-quality polar-field measurements spans relatively few sunspot cycles. In this paper we address this deficiency by consolidating Mount Wilson Observatory polar faculae data from four data reduction campaigns, validating it through a comparison with facular data counted automatically from MDI intensitygrams, and calibrating it against polar field measurements taken by the Wilcox Solar Observatory and average polar field and total polar flux calculated using MDI line-of-sight magnetograms. Our results show that the consolidated polar facular measurements are in excellent agreement with both polar field and polar flux estimates, making them an ideal proxy to study the evolution of the polar magnetic field. Additionally, we combine this database with sunspot area measurements to study the role of the ...

  19. RadioLensfit: Bayesian weak lensing measurement in the visibility domain

    CERN Document Server

    Rivi, Marzia; Makhathini, Spheshile; Abdalla, Filipe Batoni

    2016-01-01

    Observationally, weak lensing has been served so far by optical surveys due to the much larger number densities of background galaxies achieved, which is typically by two to three orders of magnitude compared to radio. However, the high sensitivity of the new generation of radio telescopes such as the Square Kilometre Array (SKA) will provide a density of detected galaxies that is comparable to that found at optical wavelengths, and with significant source shape measurements to make large area radio surveys competitive for weak lensing studies. This will lead weak lensing to become one of the primary science drivers in radio surveys too, with the advantage that they will access the largest scales in the Universe going beyond optical surveys, like LSST and Euclid, in terms of redshifts that are probed. RadioLensfit is an adaptation to radio data of "lensfit", a model-fitting approach for galaxy shear measurement, originally developed for optical weak lensing surveys. Its key advantage is working directly in th...

  20. Remote Measurement of Shallow Media Depth Using Polarization Lidar

    Science.gov (United States)

    Mitchell, Steven E.

    Active noncontact range measurement sensors transmit electromagnetic radiation onto a remote target and process the received scattered signals to resolve the separation distance, or range, between the sensor and target. For lidar sensors, range is resolved by halving the roundtrip transit time multiplied by the speed of light, accounting for the refractive indices of the transit media. The ranging technique enables remote measurement of depth by resolving the range to sequential surfaces. Depth measurement in the shallow regime has conventionally been limited by the presence of ambiguous, overlapping optical pulses scattered from sequential surfaces. Enhanced performance in the shallow regime has conventionally come at the expense of the increased cost and complexity associated with high performance componentry. The issue of remote shallow depth measurement presents an opportunity for a novel approach to lidar sensor development. In this work, I discuss how the issue of ambiguity in the shallow depth measurement may be addressed by exploiting the polarization orientation of the transmitted and received optical signals, the components of which are modified during the range observation by naturally-occurring phenomena. Conventional pulsed time of flight laser ranging sensors are unable to resolve the shallow depth between overlapping pulses received from sequential surfaces due to operation in the scalar lidar regime, where the intensity of the received scattered signal is measured with no regard for polarization information. Enhanced performance by scalar lidar sensors in the shallow media regime has been conventionally enabled through incorporation of picosecond pulse width lasers and fast photodetectors, along with their associated increase in cost and complexity. The polarization lidar approach to shallow depth measurement developed in the dissertation facilitates the use of common lasers, optics, and detection componentry, making it comparatively less complex

  1. Measurements of electronic properties of the Miyun 50 m Radio Telescope

    Institute of Scientific and Technical Information of China (English)

    Xi-Zhen Zhang; Xin-Ying Zhu; De-Qing Kong; Lei Zheng; Cheng Yao; Hong-Bo Zhang; Yan Su; Ting-Yi Piao

    2009-01-01

    Measurement results of some properties of the Miyun 50 m radio telescope (MRT50) of the National Astronomical Observatories, such as pointing calibration, an-tenna beams, system noise temperature, gain and gain variations with elevation are intro-duced. By using a new de-convolution technique developed by our group, the broadening effect on measured beams caused by the width of an extended radio source has been re-moved so that we obtained higher accuracy on the measurements of MRT50 beams.

  2. Polarization Measurement of Spin-Polarized Electrons by Optical Electron Polarimeter

    Institute of Scientific and Technical Information of China (English)

    DING Hai-Bing; PANG Wen-Ning; LIU Yi-Bao; SHANG Ren-Cheng

    2005-01-01

    @@ The polarization of spin-polarized electrons, produced from a new GaAs spin-polarized electron source, is determined by an optical electron polarimeter. The He 3 3p → 23S1 (388.9nm) transition is used for the optical electron polarimetry. The structure and performance of the experimental setup of spin-polarized electron source and optical electron polarimeter are described. The result of polarization of 30.8% averaged spin-up and spindown polarized electrons is obtained and presented.

  3. Data processing workflow for time of flight polarized neutrons inelastic measurements

    Energy Technology Data Exchange (ETDEWEB)

    Savici, Andrei T [ORNL; Zaliznyak, Igor [Brookhaven National Laboratory (BNL); Garlea, Vasile O [ORNL; Winn, Barry L [ORNL

    2017-01-01

    We discuss the data processing workflow for polarized neutron scattering measurements performed at HYSPEC spectrometer at the Spallation Neutron Source, Oak Ridge National Laboratory. The effects of the focusing Heusler crystal polarizer and the wide-angle supermirror transmission polarization analyzer are added to the data processing flow of the non-polarized case. The implementation is done using the Mantid software package.

  4. Determination of the Structure of the Coronal Magnetic Field Using Microwave Polarization Measurements

    Science.gov (United States)

    Bogod, V. M.; Yasnov, L. V.

    2016-11-01

    An analysis of the oscillatory motions and wave processes in active regions requires knowledge of the structure of the magnetic fields in the chromosphere and corona. We study the magnetic field structure of active regions at coronal heights, as they are determined by means of multiwave observations of polarized radio emission of active regions in the microwave range. Two methods, a stereoscopic method and the analysis of the radio spectrum are used. The method of stereoscopy rotation allows estimating the height of radio sources in a stable active region relative to the photosphere, based on its apparent motion in the image plane recorded over several days of observation. At various times one-dimensional scans at multiple frequencies spanning the 5.98 - 15.95 GHz frequency range from the RATAN-600 instrument are used. The gyroresonance emission mechanism, which is sensitive to the coronal magnetic field strength, is applied to convert the radio source estimated heights at various frequencies, h(f), to information as regards magnetic field vs. height, B(h). Diagrams of longitude - height of some polarized radio sources revealed multiple reversals, suggestive of a spiral magnetic structure. In all cases, the magnetic field strength maintains high values (800 - 1000 G) at the highest altitudes analysed, which reflects a relatively weak divergence in the field of magnetic flux tubes (in the height range 8 - 14 Mm) responsible for the main part of the radio emission of active regions.

  5. Measurement of W Boson Polarization in Top Quark Decay

    Energy Technology Data Exchange (ETDEWEB)

    Vickey, Trevor Neil

    2004-11-01

    A measurement of the polarization of the W boson from top quark decay is an excellent test of the V-A form of the charged-current weak interaction in the standard model. Since the longitudinal W boson is intimately related to the electroweak symmetry breaking mechanism, and the standard model gives a specific prediction for the fraction of longitudinal W bosons from top decays, it is of particular interest for study. This thesis presents a measurement of W boson polarization in top quark decays through an analysis of the cos{theta}* distribution in the lepton-plus-jets channel of t{bar t} candidate events from p{bar p} collisions at {radical}s = 1.96 TeV. This measurement uses an integrated luminosity of {approx} 162 pb{sup -1} of data collected with the CDF Run II detector, resulting in 31 t{bar t} candidate events with at least one identified b jet. Using a binned likelihood fit to the cos{theta}* distribution from the t{bar t} candidate events found in this sample, the fraction of W bosons with longitudinal polarization is determined to be F{sub 0} = 0.99{sub -0.35}{sup +0.29}(stat.) {+-} 0.19(syst.), F{sub 0} > 0.33 {at} 95% CL. This result is consistent with the standard model prediction, given a top quark mass of 174.3 GeV/c{sup 2}, of F{sub 0} = 0.701 {+-} 0.012.

  6. Measurement of W Boson Polarization in Top Quark Decay

    Energy Technology Data Exchange (ETDEWEB)

    Vickey, Trevor Neil [Univ. of Illinois, Urbana-Champaign, IL (United States)

    2004-01-01

    A measurement of the polarization of the W boson from top quark decay is an excellent test of the V-A form of the charged-current weak interaction in the standard model. Since the longitudinal W boson is intimately related to the electroweak symmetry breaking mechanism, and the standard model gives a specific prediction for the fraction of longitudinal W bosons from top decays, it is of particular interest for study. This thesis presents a measurement of W boson polarization in top quark decays through an analysis of the cosθ* distribution in the lepton-plus-jets channel of t$\\bar{t}$ candidate events from p$\\bar{p}$ collisions at √s = 1.96 TeV. This measurement uses an integrated luminosity of ~ 162 pb-1 of data collected with the CDF Run II detector, resulting in 31 t$\\bar{t}$ candidate events with at least one identified b jet. Using a binned likelihood fit to the cosθ* distribution from the t$\\bar{t}$ candidate events found in this sample, the fraction of W bosons with longitudinal polarization is determined to be F0 = 0.99$+0.29\\atop{-0.35}$stat.) ± 0.19(syst.), F0 > 0.33 @ 95% CL. This result is consistent with the standard model prediction, given a top quark mass of 174.3 GeV/c2, of F0 = 0.701 ± 0.012.

  7. The Parsec-scale Structure, Kinematics, and Polarization of Radio-Loud Narrow-Line Seyfert 1 Galaxies

    CERN Document Server

    Richards, J L; Foschini, L; Savolainen, T; Homan, D C; Kadler, M; Hovatta, T; Readhead, A C S; Arshakian, T G; Chavushyan, V

    2014-01-01

    Several narrow-line Seyfert 1 galaxies (NLS1s) have now been detected in gamma rays, providing firm evidence that at least some of this class of active galactic nuclei (AGN) produce relativistic jets. The presence of jets in NLS1s is surprising, as these sources are typified by comparatively small black hole masses and near- or super-Eddington accretion rates. This challenges the current understanding of the conditions necessary for jet production. Comparing the properties of the jets in NLS1s with those in more familiar jetted systems is thus essential to improve jet production models. We present early results from our campaign to monitor the kinematics and polarization of the parsec-scale jets in a sample of 15 NLS1s through multifrequency observations with the Very Long Baseline Array. These observations are complemented by fast-cadence 15 GHz monitoring with the Owens Valley Radio Observatory 40m telescope and optical spectroscopic monitoring with with the 2m class telescope at the Guillermo Haro Astrophy...

  8. Retrieval of aerosol single scattering albedo and polarized phase function from polarized sun-photometer measurements for Zanjan atmosphere

    Directory of Open Access Journals (Sweden)

    A. Bayat

    2013-04-01

    Full Text Available Aerosol optical depth, Ångström exponent, single scattering albedo, and polarized phase function have been retrieved from polarized sun-photometer measurements for atmosphere of Zanjan (36.70° N, 48.51° E, and 1800 m a.m.s.l. from January 2010 to December 2012. The results show that the maximum value of aerosol polarized phase function as well as the polarized phase function retrieved for a specific scattering angle (i.e. 60°, are strongly correlated with the Ångström exponent. The latter one has a meaningful variations respect to the changes in the complex refractive index of the atmospheric aerosols. Furthermore the polarized phase function shows a moderate negative correlation respect to atmospheric aerosol optical depth and single scattering albedo. Therefore the polarized phase function can be regarded as a key parameter to characterize the atmospheric particles.

  9. Using Polar Coronal Hole Area Measurements to Determine the Solar Polar Magnetic Field Reversal in Solar Cycle 24

    Science.gov (United States)

    Karna, N.; Webber, S.A. Hess; Pesnell, W.D.

    2014-01-01

    An analysis of solar polar coronal hole (PCH) areas since the launch of the Solar Dynamics Observatory (SDO) shows how the polar regions have evolved during Solar Cycle 24. We present PCH areas from mid-2010 through 2013 using data from the Atmospheric Imager Assembly (AIA) and Helioseismic and Magnetic Imager (HMI) instruments onboard SDO. Our analysis shows that both the northern and southern PCH areas have decreased significantly in size since 2010. Linear fits to the areas derived from the magnetic-field properties indicate that, although the northern hemisphere went through polar-field reversal and reached solar-maximum conditions in mid-2012, the southern hemisphere had not reached solar-maximum conditions in the polar regions by the end of 2013. Our results show that solar-maximum conditions in each hemisphere, as measured by the area of the polar coronal holes and polar magnetic field, will be offset in time.

  10. Towards Polarization Measurements of Laser-accelerated Helium-3 Ions

    OpenAIRE

    Engin, Ilhan

    2016-01-01

    In the framework of this thesis, preparatory investigations for the spin-polarization measurement of 3He ions from laser-induced plasmas have been performed.Therefore, experiments aiming at an efficient laser-induced ion acceleration out of a 4He gas target were carried out at two high-intensity laser facilities: the Arcturus laser at Heinrich-Heine-Universität Düsseldorf as well as PHELIX at GSI Darmstadt. The scientific goal of both experiments was to investigate the ion-acceleration proces...

  11. Measurement Of W Boson Polarization In Top Quark Decay

    CERN Document Server

    Vickey, T N

    2004-01-01

    A measurement of the polarization of the W boson from top quark decay is an excellent test of the V − A form of the charged-current weak interaction in the standard model. Since the longitudinal W boson is intimately related to the electroweak symmetry breaking mechanism, and the standard model gives a specific prediction for the fraction of longitudinal W bosons from top decays, it is of particular interest for study. This thesis presents a measurement of W boson polarization in top quark decays through an analysis of the cos&thetas;* distribution in the lepton-plus-jets channel of tt¯ candidate vents from pp¯ collisions at s = 1.96 TeV. This measurement uses an integrated luminosity of ∼162 pb−1 of data collected with the CDF Run II detector, resulting in 31 tt¯ candidate events with at least one identified b jet. Using a binned likelihood fit to the cos&thetas;* distribution from the tt¯ candidate events found in this sample, the f...

  12. Accelerator measurements of magnetically-induced radio emission from particle cascades with applications to cosmic-ray air showers

    CERN Document Server

    Belov, K; Romero-Wolf, A; Wissel, S A; Zilles, A; Bechtol, K; Borch, K; Chen, P; Clem, J; Gorham, P W; Hast, C; Huege, T; Hyneman, R; Jobe, K; Kuwatani, K; Lam, J; Liu, T; Nam, J; Naudet, C; Nichol, R; Rauch, B F; Rotter, B; Saltzberg, D; Schoorlemmer, H; Seckel, D; Strutt, B; Vieregg, A G; Williams, C

    2015-01-01

    An experiment at SLAC provides the first beam test of radio-frequency (RF) radiation from a charged particle cascade in the presence of a magnetic field (up to $\\sim$1~kG), a model system for RF emission from a cosmic-ray air shower. This experiment provides a suite of controlled laboratory measurements to compare to particle-level simulations of RF emission, which are relied upon in ultra-high-energy cosmic-ray air shower detection. We compare simulations to data for intensity, linearity with magnetic field, angular distribution, polarization, and spectral content. In particular, we confirm recent predictions that the magnetically induced emission forms a beam that peaks at the Cherenkov angle and show that the simulations reproduce the data within systematic uncertainties.

  13. Search for Physics Beyond the Standard Model via Positron Polarization Measurements with Polarized $ ^{17} $F.

    CERN Multimedia

    Versyck, S

    2002-01-01

    This proposal aims at measuring the longitudinal polarization of positrons emitted from polarized $^{17} $F~nuclei. The experiment will have a comparable sensitivity to possible right-handed current contributions in the weak interaction as the experiment which was recently carried out with $ ^{107} $In in Louvain-la-Neuve, but will provide a more stringent limit due to the fact that, since $ ^{17} $F decays through a superallowed $\\beta$ -transition, the recoil-order corrections to the allowed approximation can be taken into account very precisely. Furthermore, because $ ^{17} $F decays via a mixed Fermi/Gamow-Teller $\\beta$ -transition, this experiment will also yield a new limit on possible scalar contributions to the weak interaction. While the $^{17}$F beam is being developed, part of the beamtime was used to perform a similar experiment with $^{118}$ Sb. As this isotope decays via a pure GT $\\beta$ -transition, this experiment will yield new limits on the possible presence of both right-handed and tensor...

  14. Distributed measurement of mode coupling in birefringent fibers with random polarization modes

    CERN Document Server

    Xu, Tianhua; Jing, Wencai; Zhang, Hongxia; Jia, Dagong; Zhang, Xuemin; Zhou, Ge; Zhang, Yimo

    2016-01-01

    A scanning white light interferometer is developed to measure the distributed polarization coupling (DPC) in high birefringence polarization maintaining fibers (PMFs). Traditionally, this technique requests only one polarization mode to be excited or both polarization modes to be excited with equal intensity in the PMF. Thus, an accurate alignment of the polarization direction with the principal axis in PMF is strictly required, which is not facilely realized in practical measurement. This paper develops a method to measure the spatial distribution of polarization mode coupling with random modes excited using a white light Michelson interferometer. The influence of incident polarization extinction ratio (PER) on polarization coupling detection is evaluated theoretically and experimentally. It is also analyzed and validated in corresponding measurement that the sensitivity of the polarization coupling detection system can be improved more than 100 times with the rotation of the analyzer.

  15. Receiver for 6-cm Polarization Observation Starts Working

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ A 6-cm receiving system with a polarimeter, made by engineers of German MaxPlanck-Institute for Radioastronomy, has been installed to the 25 radio telescope in Urumqi, the capital of western China's Xinjiang Uygur Autonomous Region. The new instrument for Sino-German cooperation on radio astronomy will enable Chinese astronomers to measure the polarization of radio sources for the first time.

  16. Design of Measurement System for Determining the Radioclimatology Effect on the Radio Signal Propagation Using Universal Software Radio

    Directory of Open Access Journals (Sweden)

    Martin Tomis

    2013-01-01

    Full Text Available In this paper, a developed point-to-point wireless link using Universal Software Radio Peripheral (USRP is presented. The aim of the research is focused on the monitoring and analysing the transmission characteristics on the physical layer of such wireless communication link with the consideration that these parameters could be affected by atmospheric phenomenon and air pollution. For that reason, the wireless link is situated to heavily loaded environment of Ostrava agglomeration where it is assumed extreme atmospheric phenomena such as smog or inverse situation. In the next part, a developed application which perform a fully automatic long term measurement of the transmission characteristics using a wireless link is presented. Finally, the first experimental results based on mathematical regression are presented.

  17. LOPES 3D - vectorial measurements of radio emission from cosmic ray induced air showers

    CERN Document Server

    Apel, W D; Bähren, L; Bekk, K; Bertaina, M; Biermann, P L; Blümer, J; Bozdog, H; Brancus, I M; Chiavassa, A; Daumiller, K; de Souza, V; Di Pierro, F; Doll, P; Engel, R; Falcke, H; Fuchs, B; Fuhrmann, D; Gemmeke, H; Grupen, C; Haungs, A; Heck, D; Hörandel, J R; Horneffer, A; Huber, D; Huege, T; Isar, P G; Kampert, K -H; Kang, D; Krömer, O; Kuijpers, J; Link, K; Luczak, P; Ludwig, M; Mathes, H J; Melissas, M; Morello, C; Oehlschläger, J; Palmieri, N; Pierog, T; Rautenberg, J; Rebel, H; Roth, M; Rühle, C; Saftoiu, A; Schieler, H; Schmidt, A; Schröder, F G; Sima, O; Toma, G; Trinchero, G C; Weindl, A; Wochele, J; Zabierowski, J; Zensus, J A

    2013-01-01

    LOPES 3D is able to measure all three components of the electric field vector of the radio emission from air showers. This allows a better comparison with emission models. The measurement of the vertical component increases the sensitivity to inclined showers. By measuring all three components of the electric field vector LOPES 3D demonstrates by how much the reconstruction accuracy of primary cosmic ray parameters increases. Thus LOPES 3D evaluates the usefulness of vectorial measurements for large scale applications.

  18. Neutron Polarization Measurements with a 3He Spin Filter for the NPDGamma Experiment

    Science.gov (United States)

    Musgrave, Matthew

    2012-10-01

    The Fundamental Neutron Physics Beamline (FNPB) at the Spallation Neutron Source (SNS) provides a pulsed beam of polarized cold neutrons for the NPDGamma experiment which intends to measure the parity violating asymmetry in the emitted gamma rays from the capture of polarized neutrons on protons in a para-hydrogen target. The neutrons are polarized by a multi-channel super mirror polarizer, and the polarization of each neutron pulse can be flipped with an RF spin rotator. The accuracy of the NPDGamma experiment and various commissioning experiments is dependent on the polarization of the neutron beam and the efficiency of the RF spin rotator. These parameters are measured with a polarized 3He spin filter at multiple points in the beam cross section and with multiple 3He polarizations. The measured neutron polarization is compared to a McStas model to validate our results and our beam averaging technique. The analysis methods, background effects, and results will be discussed.

  19. Measurement of horizontal air showers with the Auger Engineering Radio Array

    CERN Document Server

    Kambeitz, Olga

    2016-01-01

    The Auger Engineering Radio Array (AERA), at the Pierre Auger Observatory in Argentina, measures the radio emission of extensive air showers in the 30-80 MHz frequency range. AERA consists of more than 150 antenna stations distributed over 17 km$^2$. Together with the Auger surface detector, the fluorescence detector and the under-ground muon detector (AMIGA), AERA is able to measure cosmic rays with energies above 10$^{17}$ eV in a hybrid detection mode. AERA is optimized for the detection of air showers up to 60$^{\\circ}$ zenith angle, however, using the reconstruction of horizontal air showers with the Auger surface array, very inclined showers can also be measured. In this contribution an analysis of the AERA data in the zenith angle range from 62$^{\\circ}$ to 80$^{\\circ}$ will be presented. CoREAS simulations predict radio emission footprints of several km$^2$ for horizontal air showers, which are now confirmed by AERA measurements. This can lead to radio-based composition measurements and energy determi...

  20. Occupational exposure of personnel operating military radio equipment: measurements and simulation.

    Science.gov (United States)

    Paljanos, Annamaria; Miclaus, Simona; Munteanu, Calin

    2015-09-01

    Technical literature provides numerous studies concerning radiofrequency exposure measurements for various radio communication devices, but there are few studies related to exposure of personnel operating military radio equipment. In order to evaluate exposure and identify cases when safety requirements are not entirely met, both measurements and simulations are needed for accurate results. Moreover, given the technical characteristics of the radio devices used in the military, personnel mainly operate in the near-field region so both measurements and simulation becomes more complex. Measurements were made in situ using a broadband personal exposimeter equipped with two isotropic probes for both electric and magnetic components of the field. The experiment was designed for three different operating frequencies of the same radio equipment, while simulations were made in FEKO software using hybrid numerical methods to solve complex electromagnetic field problems. The paper aims to discuss the comparative results of the measurements and simulation, as well as comparing them to reference levels specified in military or civilian radiofrequency exposure standards.

  1. Probing magnetars magnetosphere through X-ray polarization measurements

    CERN Document Server

    Taverna, Roberto; Turolla, Roberto; Soffitta, Paolo; Fabiani, Sergio; Nobili, Luciano

    2013-01-01

    The study of magnetars is of particular relevance since these objects are the only laboratories where the physics in ultra-strong magnetic fields can be directly tested. Until now, spectroscopic and timing measurements at X-ray energies in soft gamma-repeaters (SGRs) and anomalous X-ray pulsar (AXPs) have been the main source of information about the physical properties of a magnetar and of its magnetosphere. Spectral fitting in the ~ 0.5-10 keV range allowed to validate the "twisted magnetosphere" model, probing the structure of the external field and estimating the density and velocity of the magnetospheric currents. Spectroscopy alone, however, may fail in disambiguating the two key parameters governing magnetospheric scattering (the charge velocity and the twist angle) and is quite insensitive to the source geometry. X-ray polarimetry, on the other hand, can provide a quantum leap in the field by adding two extra observables, the linear polarization degree and the polarization angle. Using the bright AXP ...

  2. Angular Scattering Reflectance and Polarization Measurements of Candidate Regolith Materials Measured in the Laboratory

    Science.gov (United States)

    Nelson, Robert M.; Boryta, Mark D.; Hapke, Bruce W.; Shkuratov, Yuriy; Vandervoort, Kurt; Vides, Christina L.

    2016-10-01

    The reflectance and polarization of light reflected from a solar system object indicates the chemical and textural state of the regolith. Remote sensing data are compared to laboratory angular scattering measurements and surface properties are determined.We use a Goniometric Photopolarimeter (GPP) to make angular reflectance and polarization measurements of particulate materials that simulate planetary regoliths. The GPP employs the Helmholtz Reciprocity Principle ( 2, 1) - the incident light is linearly polarized - the intensity of the reflected component is measured. The light encounters fewer optical surfaces improving signal to noise. The lab data are physically equivalent to the astronomical data.Our reflectance and polarization phase curves of highly reflective, fine grained, media simulate the regolith of Jupiter's satellite Europa. Our lab data exhibit polarization phase curves that are very similar to reports by experienced astronomers (4). Our previous reflectance phase curve data of the same materials agree with the same astronomical observers (5). We find these materials exhibit an increase in circular polarization ratio with decreasing phase angle (3). This suggests coherent backscattering (CB) of photons in the regolith (3). Shkuratov et al.(3) report that the polarization properties of these particulate media are also consistent with the CB enhancement process (5). Our results replicate the astronomical data indicating Europa's regolith is fine-grained, high porous with void space exceeding 90%.1. Hapke, B. W. (2012). ISBN 978-0-521-88349-82. Minnaert, M. (1941).Asrophys. J., 93, 403-410.3. Nelson, R. M. et al. (1998). Icarus, 131, 223-230.4. Rosenbush, V. et al. (2015). ISBN 978-1-107-04390-9, pp 340-359.5. Shkuratov, Yu. et al. (2002) Icarus 159, 396-416.

  3. Measuring the self-healing of the spatially inhomogeneous states of polarization of vector Bessel beams

    CSIR Research Space (South Africa)

    Milione, G

    2015-02-01

    Full Text Available We experimentally measured the self-healing of the spatially inhomogeneous states of polarization of vector Bessel beams. Radially and azimuthally polarized vector Bessel beams were experimentally generated via a digital version of Durnin's method...

  4. Lunar occultation of the diffuse radio sky: LOFAR measurements between 35 and 80 MHz

    NARCIS (Netherlands)

    H.K. Vedantham; . et al.; S. Markoff; J. Swinbank; M.W. Wise

    2015-01-01

    We present radio observations of the Moon between 35 and 80 MHz to demonstrate a novel technique of interferometrically measuring large-scale diffuse emission extending far beyond the primary beam (global signal) for the first time. In particular, we show that (i) the Moon appears as a negative-flux

  5. The Large Office Environment - Measurement and Modeling of the Wideband Radio Channel

    DEFF Research Database (Denmark)

    Andersen, Jørgen Bach; Nielsen, Jesper Ødum; Bauch, Gerhard

    2006-01-01

    In a future 4G or WLAN wideband application we can imagine multiple users in a large office environment con-sisting of a single room with partitions. Up to now, indoor radio channel measurement and modelling has mainly concentrated on scenarios with several office rooms and corridors. We present...

  6. Measurement of cosmic-ray air showers with the Tunka Radio Extension (Tunka-Rex)

    CERN Document Server

    Bezyazeekov, P A; Gress, O A; Haungs, A; Hiller, R; Huege, T; Kazarina, Y; Kleifges, M; Konstantinov, E N; Korosteleva, E E; Kostunin, D; Krömer, O; Kuzmichev, L A; Levinson, E; Lubsandorzhiev, N; Mirgazov, R R; Monkhoev, R; Pakhorukov, A; Pankov, L; Prosin, V V; Rubtsov, G I; Rühle, C; Schröder, F G; Wischnewski, R; Zagorodnikov, A

    2015-01-01

    Tunka-Rex is a radio detector for cosmic-ray air showers in Siberia, triggered by Tunka-133, a co-located air-Cherenkov detector. The main goal of Tunka-Rex is the cross-calibration of the two detectors by measuring the air-Cherenkov light and the radio signal emitted by the same air showers. This way we can explore the precision of the radio-detection technique, especially for the reconstruction of the primary energy and the depth of the shower maximum. The latter is sensitive to the mass of the primary cosmic-ray particles. In this paper we describe the detector setup and explain how electronics and antennas have been calibrated. The analysis of data of the first season proves the detection of cosmic-ray air showers and therefore, the functionality of the detector. We confirm the expected dependence of the detection threshold on the geomagnetic angle and the correlation between the energy of the primary cosmic-ray particle and the radio amplitude. Furthermore, we compare reconstructed amplitudes of radio pu...

  7. Measurements and modelling of radio propagation in subway tunnels

    OpenAIRE

    2013-01-01

    The work presented in this article is focused on the RF measurement campaign carried out in several subway tunnels in Metro Madrid (Spain). Most common segments such as straight lines, curves and passing through station as well as other unique scenarios in metropolitan lines were the selected locations during this campaign. Measurements were conducted in tunnels of diverse cross section shapes and taken at three frequency bands: 900 MHz, 2.4GHz and 5.7 GHz for both horizontal and vertical pol...

  8. Measurement of Deuteron Tensor Polarization in Elastic Electron Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Gustafsson, Kenneth K. [Univ. of Maryland, College Park, MD (United States)

    2000-01-01

    Nuclear physics traces it roots back to the very beginning of the last century. The concept of the nuclear atom was introduced by Rutherford around 1910. The discovery of the neutron Chadwick in 1932 gave us the concept of two nucleons: the proton and the neutron. The Jlab electron accelerator with its intermediate energy high current continuous wave beam combined with the Hall C high resolution electron spectrometer and a deutron recoil polarimeter provided experiment E94018 with the opportunity to study the deuteron electomagnetic structure, in particular to measure the tensor polarization observable t20, at high four momentum transfers than ever before. This dissertation presents results of JLab experiment E94018.

  9. Radio Weak Lensing Shear Measurement in the Visibility Domain - I. Methodology

    Science.gov (United States)

    Rivi, M.; Miller, L.; Makhathini, S.; Abdalla, F. B.

    2016-08-01

    The high sensitivity of the new generation of radio telescopes such as the Square Kilometre Array (SKA) will allow cosmological weak lensing measurements at radio wavelengths that are competitive with optical surveys. We present an adaptation to radio data of lensfit, a method for galaxy shape measurement originally developed and used for optical weak lensing surveys. This likelihood method uses an analytical galaxy model and makes a Bayesian marginalisation of the likelihood over uninteresting parameters. It has the feature of working directly in the visibility domain, which is the natural approach to adopt with radio interferometer data, avoiding systematics introduced by the imaging process. As a proof of concept, we provide results for visibility simulations of individual galaxies with flux density S ≥ 10μJy at the phase centre of the proposed SKA1-MID baseline configuration, adopting 12 frequency channels in the band 950 - 1190 MHz. Weak lensing shear measurements from a population of galaxies with realistic flux and scalelength distributions are obtained after natural gridding of the raw visibilities. Shear measurements are expected to be affected by `noise bias': we estimate the bias in the method as a function of signal-to-noise ratio (SNR). We obtain additive and multiplicative bias values that are comparable to SKA1 requirements for SNR > 18 and SNR > 30, respectively. The multiplicative bias for SNR >10 is comparable to that found in ground-based optical surveys such as CFHTLenS, and we anticipate that similar shear measurement calibration strategies to those used for optical surveys may be used to good effect in the analysis of SKA radio interferometer data.

  10. Radio weak lensing shear measurement in the visibility domain - I. Methodology

    Science.gov (United States)

    Rivi, M.; Miller, L.; Makhathini, S.; Abdalla, F. B.

    2016-12-01

    The high sensitivity of the new generation of radio telescopes such as the Square Kilometre Array (SKA) will allow cosmological weak lensing measurements at radio wavelengths that are competitive with optical surveys. We present an adaptation to radio data of lensfit, a method for galaxy shape measurement originally developed and used for optical weak lensing surveys. This likelihood method uses an analytical galaxy model and makes a Bayesian marginalization of the likelihood over uninteresting parameters. It has the feature of working directly in the visibility domain, which is the natural approach to adopt with radio interferometer data, avoiding systematics introduced by the imaging process. As a proof of concept, we provide results for visibility simulations of individual galaxies with flux density S ≥ 10 μJy at the phase centre of the proposed SKA1-MID baseline configuration, adopting 12 frequency channels in the band 950-1190 MHz. Weak lensing shear measurements from a population of galaxies with realistic flux and scalelength distributions are obtained after natural gridding of the raw visibilities. Shear measurements are expected to be affected by `noise bias': we estimate the bias in the method as a function of signal-to-noise ratio (SNR). We obtain additive and multiplicative bias values that are comparable to SKA1 requirements for SNR > 18 and SNR > 30, respectively. The multiplicative bias for SNR >10 is comparable to that found in ground-based optical surveys such as CFHTLenS, and we anticipate that similar shear measurement calibration strategies to those used for optical surveys may be used to good effect in the analysis of SKA radio interferometer data.

  11. Radio emission of the sun and planets

    CERN Document Server

    Zheleznyakov, V V

    1970-01-01

    International Series of Monographs in Natural Philosophy, Volume 25: Radio Emission of the Sun and Planets presents the origin of the radio emission of the planets. This book examines the outstanding triumphs achieved by radio astronomy of the solar system. Comprised of 10 chapters, this volume begins with an overview of the physical conditions in the upper layers of the Sun, the Moon, and the planets. This text then examines the three characteristics of radio emission, namely, the frequency spectrum, the polarization, and the angular spectrum. Other chapters consider the measurements of the i

  12. Radio Polarization Observations of the Snail: A Crushed Pulsar Wind Nebula in G327.1-1.1 with a Highly Ordered Magnetic Field

    CERN Document Server

    Ma, Y K; Bucciantini, N; Slane, P O; Gaensler, B M; Temim, T

    2016-01-01

    Pulsar wind nebulae (PWNe) are suggested to be acceleration sites of cosmic rays in the Galaxy. While the magnetic field plays an important role in the acceleration process, previous observations of magnetic field configurations of PWNe are rare, particularly for evolved systems. We present a radio polarization study of the "Snail" PWN inside the supernova remnant G327.1-1.1 using the Australia Telescope Compact Array. This PWN is believed to have been recently crushed by the supernova (SN) reverse shock. The radio morphology is composed of a main circular body with a finger-like protrusion. We detected a strong linear polarization signal from the emission, which reflects a highly ordered magnetic field in the PWN and is in contrast to the turbulent environment with a tangled magnetic field generally expected from hydrodynamical simulations. This could suggest that the characteristic turbulence scale is larger than the radio beam size. We built a toy model to explore this possibility, and found that a simulat...

  13. RADIO POLARIZATION OBSERVATIONS OF THE SNAIL: A CRUSHED PULSAR WIND NEBULA IN G327.1–1.1 WITH A HIGHLY ORDERED MAGNETIC FIELD

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Y. K.; Ng, C.-Y. [Department of Physics, The University of Hong Kong, Pokfulam Road (Hong Kong); Bucciantini, N. [INAF—Osservatorio Astrofisico di Arcetri, L.go E. Fermi 5, I-50125 Firenze (Italy); Slane, P. O. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Gaensler, B. M. [Dunlap Institute for Astronomy and Astrophysics, The University of Toronto, Toronto, ON M5S 3H4 (Canada); Temim, T., E-mail: ncy@bohr.physics.hku.hk [Observational Cosmology Lab, Code 665, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2016-04-01

    Pulsar wind nebulae (PWNe) are suggested to be acceleration sites of cosmic rays in the Galaxy. While the magnetic field plays an important role in the acceleration process, previous observations of magnetic field configurations of PWNe are rare, particularly for evolved systems. We present a radio polarization study of the “Snail” PWN inside the supernova remnant G327.1−1.1 using the Australia Telescope Compact Array. This PWN is believed to have been recently crushed by the supernova (SN) reverse shock. The radio morphology is composed of a main circular body with a finger-like protrusion. We detected a strong linear polarization signal from the emission, which reflects a highly ordered magnetic field in the PWN and is in contrast to the turbulent environment with a tangled magnetic field generally expected from hydrodynamical simulations. This could suggest that the characteristic turbulence scale is larger than the radio beam size. We built a toy model to explore this possibility, and found that a simulated PWN with a turbulence scale of about one-eighth to one-sixth of the nebula radius and a pulsar wind filling factor of 50%–75% provides the best match to observations. This implies substantial mixing between the SN ejecta and pulsar wind material in this system.

  14. Method for using polarization gating to measure a scattering sample

    Energy Technology Data Exchange (ETDEWEB)

    Baba, Justin S.

    2015-08-04

    Described herein are systems, devices, and methods facilitating optical characterization of scattering samples. A polarized optical beam can be directed to pass through a sample to be tested. The optical beam exiting the sample can then be analyzed to determine its degree of polarization, from which other properties of the sample can be determined. In some cases, an apparatus can include a source of an optical beam, an input polarizer, a sample, an output polarizer, and a photodetector. In some cases, a signal from a photodetector can be processed through attenuation, variable offset, and variable gain.

  15. Retrieval of aerosol single-scattering albedo and polarized phase function from polarized sun-photometer measurements for Zanjan's atmosphere

    Directory of Open Access Journals (Sweden)

    A. Bayat

    2013-10-01

    Full Text Available The polarized phase function of atmospheric aerosols has been investigated for the atmosphere of Zanjan, a city in northwest Iran. To do this, aerosol optical depth, Ångström exponent, single-scattering albedo, and polarized phase function have been retrieved from the measurements of a Cimel CE 318-2 polarized sun-photometer from February 2010 to December 2012. The results show that the maximum value of aerosol polarized phase function as well as the polarized phase function retrieved for a specific scattering angle (i.e., 60° are strongly correlated (R = 0.95 and 0.95, respectively with the Ångström exponent. The latter has a meaningful variation with respect to the changes in the complex refractive index of the atmospheric aerosols. Furthermore the polarized phase function shows a moderate negative correlation with respect to the atmospheric aerosol optical depth and single-scattering albedo (R = −0.76 and −0.33, respectively. Therefore the polarized phase function can be regarded as a key parameter to characterize the atmospheric particles of the region – a populated city in the semi-arid area and surrounded by some dust sources of the Earth's dust belt.

  16. Measuring x-ray polarization in the presence of systematic effects: Known background

    CERN Document Server

    Elsner, Ronald F; Weisskopf, Martin C

    2012-01-01

    The prospects for accomplishing x-ray polarization measurements of astronomical sources have grown in recent years, after a hiatus of more than 37 years. Unfortunately, accompanying this long hiatus has been some confusion over the statistical uncertainties associated with x-ray polarization measurements of these sources. We have initiated a program to perform the detailed calculations that will offer insights into the uncertainties associated with x-ray polarization measurements. Here we describe a mathematical formalism for determining the 1- and 2-parameter errors in the magnitude and position angle of x-ray (linear) polarization in the presence of a (polarized or unpolarized) background. We further review relevant statistics-including clearly distinguishing between the Minimum Detectable Polarization (MDP) and the accuracy of a polarization measurement.

  17. Light-scattering polarization measurements as a new parameter in flow cytometry

    NARCIS (Netherlands)

    Grooth, de B.G.; Terstappen, L.W.M.M.; Puppels, G.J.; Greve, J.

    1987-01-01

    Polarization measurement of orthogonal light scattering is introduced as a new optical parameter in flow cytometry. In the experimental setup, the electrical field of the incident laser beam is polarized in the direction of the sample flow. The intensity of the orthogonal light scattering polarized

  18. Numerical modeling of the inception, morphology and radio signals of sprites produced by lightning discharges with positive and negative polarity

    Science.gov (United States)

    Qin, Jianqi

    conditions (i.e., the ambient electron and ion density) on the threshold charge moment changes required to produce column sprites and carrot sprites. To understand the lightning polarity asymmetry in producing sprites, we investigate possible differences between the requirements for the initiation of positive and negative sprites. A parametric study shows that positive sprites require an ambient electric field with smaller magnitude and shorter persistence when compared to those required for the initiation of negative sprites. Consequently, the initiation of positive sprites requires a smaller threshold charge moment change than that of negative sprites (320 C km and 500 C km, respectively, under typical nighttime conditions). This difference between the initiation thresholds represents one of the key factors accounting for the polarity asymmetry of sprites. Other factors, including the charge moment contrast of +CGs and -CGs, and the differences originating from physical properties of streamers and observability of positive and negative sprites are also discussed. This dissertation work presents the first theoretical estimates of the electromagnetic radiation produced by individual sprite streamers using simulation results from plasma fluid modeling. It is demonstrated that the spectral content of the sprite radiation is highly dependent on the air density and the ambient electric field, i.e., sprite streamers propagating at lower altitudes with higher air density or propagating in a higher electric field produce a higher frequency radiation. Most interestingly, we quantitatively demonstrate that sprite streamers at low altitudes (˜40 km) can produce VLF and LF radiation, that needs to be confirmed by future radio observations. Finally, this dissertation work presents research efforts that are devoted to a direct comparison of morphological features predicted by the streamer model with those appearing in video observations in order to derive the mechanism of column and

  19. A technique for measurement of vector and tensor polarization in solid spin one polarized targets

    Energy Technology Data Exchange (ETDEWEB)

    Kielhorn, W.F.

    1991-06-01

    Vector and tensor polarizations are explicitly defined and used to characterize the polarization states of spin one polarized targets, and a technique for extracting these polarizations from nuclear magnetic resonance (NMR) data is developed. This technique is independent of assumptions about spin temperature, but assumes the target's crystal structure induces a quadrupole interaction with the spin one particles. Analysis of the NMR signals involves a computer curve fitting algorithm implemented with a fast Fourier transform method which speeds and simplifies curve fitting algorithms used previously. For accurate curve fitting, the NMR electronic circuit must be modeled by the fitting algorithm. Details of a circuit, its model, and data collected from this circuit are given for a solid deuterated ammonia target. 37 refs., 19 figs., 3 tabs.

  20. Spectral induced polarization (SIP) measurement of NAPL contaminated soils

    Science.gov (United States)

    Schwartz, N.; Huisman, J. A.; Furman, A.

    2010-12-01

    The potential applicability of spectral induce polarization (SIP) as a tool to map NAPLs (non aqueous phase liquids) contaminants at the subsurface lead researchers to investigate the electric signature of those contaminant on the spectral response. However, and despite the cumulative efforts, the effect of NAPL on the electrical properties of soil, and the mechanisms that control this effect are largely unknown. In this work a novel experiment is designed to further examine the effect of NAPL on the electrical properties of partially saturated soil. The measurement system that used is the ZEL-SIP04 impedance meter developed at the Forschungszentrum Julich, Germany. The system accurately (nominal phase precision of 0.1 mrad below 1 kHz) measures the phase and the amplitude of a material possessing a very low polarization (such as soil). The sample holder has a dimension of 60 cm long and 4.6 cm in diameter. Current and potential electrodes were made of brass, and while the current electrodes were inserted in full into the soil, the contact between the potential electrode and the soil was made through an Agarose bridge. Two types of soils were used: clean quartz sand, and a mixture of sand with clean Bentonite. Each soil (sandy or clayey) was mixed with water to get saturation degree of 30%. Following the mixture with water, NAPL was added and the composite were mixed again. Packing was done by adding and compressing small portions of the soil to the column. A triplicate of each mixture was made with a good reproducible bulk density. Both for the sandy and clayey soils, the results indicate that additions of NAPL decrease the real part of the complex resistivity. Additionally, for the sandy soil this process is time depended, and that a further decrease in resistivity develops over time. The results are analyzed considering geometrical factors: while the NAPL is electrically insulator, addition of NAPL to the soil is expected to increase the connectivity of the

  1. A proposed space mission around the Moon to measure the Moon Radio-Quiet Zone

    Science.gov (United States)

    Antonietti, N.; Pagana, G.; Pluchino, S.; Maccone, C.

    In a series of papers published since 2000 mainly in Acta Astronautica the senior author Maccone dealt with the advantages of the Farside of the Moon for future utilization Clearly the Moon Farside is free from RFI Radio Frequency Interference produced in larger and larger amounts by the increasing human exploitation of radio technologies That author suggested that crater Daedalus located at the center of the Farside was the best possible location to build up in the future one or more radiotelescopes or phased arrays to achieve the maximum sensitivity in radioastronomical and SETI searches Also a radio-quiet region of space above the Farside of the Moon exists and is called the Quiet Cone The Quiet Cone actual size however is largely unknown since it depends on the orbits of radio-emitting satellites around the Earth that are themselves largely unknown due to the military involvements In addition diffraction of electromagnetic waves grazing the surface of the Moon causes further changes in the geometrical shape of the Quiet Cone This riddle can be solved only by direct measurements of the radio attenuation above the Farside of the Moon performed by satellites orbiting the Moon itself In this paper we propose to let one or more low cost radiometers be put into orbit around the Moon to measure the RFI attenuation at different frequencies and altitudes above the Moon The opportunity of adding more payload s such as an ion detector and or a temperature sensor is evaluated also In this regard we present in this paper the experience gained by

  2. Highly precise and accurate terahertz polarization measurements based on electro-optic sampling with polarization modulation of probe pulses.

    Science.gov (United States)

    Nemoto, Natsuki; Higuchi, Takuya; Kanda, Natsuki; Konishi, Kuniaki; Kuwata-Gonokami, Makoto

    2014-07-28

    We have developed an electro-optic (EO) sampling method with polarization modulation of probe pulses; this method allows us to measure the direction of a terahertz (THz) electric-field vector with a precision of 0.1 mrad in a data acquisition time of 660 ms using a 14.0-kHz repetition rate pulsed light source. Through combination with a THz time-domain spectroscopy technique, a time-dependent two-dimensional THz electric field was obtained. We used a photoelastic modulator for probe-polarization modulation and a (111)-oriented zincblende crystal as the EO crystal. Using the tilted pulse front excitation method with stable regeneratively amplified pulses, we prepared stable and intense THz pulses and performed pulse-by-pulse analog-to-digital conversion of the signals. These techniques significantly reduced statistical errors and enabled sub-mrad THz polarization measurements. We examined the performance of this method by measuring a wire-grid polarizer as a sample. The present method will open a new frontier of high-precision THz polarization sensitive measurements.

  3. Precipitation measurements with GNSS polarimetric Radio Occultations: Status of the ROHP-PAZ mission and anticipated retrievals

    Science.gov (United States)

    Padullés, Ramon; Cardellach, Estel; de la Torre Juárez, Manuel; Tomás, Sergio; Turk, F. Joseph; Ao, Chi O.; Rius, Toni; Oliveras, Santi

    2016-04-01

    The upcoming ROHP-PAZ (Radio Occultations and Heavy Precipitation experiment aboard the spanish PAZ satellite) mission aims to detect, for the first time, precipitation using Global Navigation Satellite System Radio Occultations (GNSS-RO). The electromagnetic signals coming from the GNSS satellites travel tangentially through the atmosphere and will be collected in the PAZ Low Earth Orbiter at two polarizations (vertical and horizontal). This sounding-like technique of the atmosphere will measure all the atmospheric phenomena that are inducing depolarization effects, in addition to all the thermodynamic profiles that standard RO are nowadays providing. The main contributors to depolarization in the troposphere are known to be the hydrometeors, both rain drops from heavy precipitation events and horizontally oriented ice particles in the top of clouds. Their effects on the GNSS signals were predicted in Cardellach et. al. 2015 (IEEE Trans. Geosci. Remote Sens.), and measured in the ROHP-PAZ field campaign Padullés et. al. 2016 (Atmos. Chem. Phys.). Prior to the launch, a complete characterization of all the possible effects, including hydrometeors but also taking into account other elements was needed. To do so, actual data from the COSMIC - FORMOSAT 3 mission (Radio Occultation events) have been collocated with the TRMM, GPM and CloudSat missions (precipitation and clouds missions). Thousands of events have been analyzed, in terms of SNR and phase delays. For the same events, the effect of hydrometeors has been simulated as well as the most known ionospheric effects, such as Faraday Rotation and Cotton-Mouton effects. And finally, the predicted noise, actual measurements of the antenna pattern and some tolerance in the purity of the emitted signal have been included. This has resulted in an extensive data base that is key in the understanding of the upcoming actual data, as well as for the characterization of all the unpredicted effects. We will discuss here the

  4. Indoor radio measurement and planning for UMTS/HSDPA with antennas

    Science.gov (United States)

    Eheduru, Marcellinus

    Over the last decade, mobile communication networks have evolved tremendously with a key focus on providing high speed data services in addition to voice. The third generation of mobile networks in the form of Universal Mobile Telecommunications System (UMTS) is already offering revolutionary mobile broadband experience to its users by deploying High Speed Downlink Packet Access (HSDPA) as its packet-data technology. With data speeds up to 14.4 Mbps and ubiquitous mobility, HSDPA is anticipated to become a preferred broadband access medium for end-users via mobile phones, laptops etc. While majority of these end-users are located indoors most of the time, approximately 70-80% of the HSDPA traffic is estimated to originate from inside buildings. Thus for network operators, indoor coverage has become a necessity for technical and business reasons. Macro-cellular (outdoor) to indoor coverage is a natural inexpensive way of providing network coverage inside the buildings. However, it does not guarantee sufficient link quality required for optimal HSDPA operation. On the contrary, deploying a dedicated indoor system may be far too expensive from an operator's point of view. In this thesis, the concept is laid for the understanding of indoor radio wave propagation in a campus building environment which could be used to plan and improve outdoor-to-indoor UMTS/HSDPA radio propagation performance. It will be shown that indoor range performance depends not only on the transmit power of an indoor antenna, but also on the product's response to multipath and obstructions in the environment along the radio propagation path. An extensive measurement campaign will be executed in different indoor environments analogous to easy, medium and hard radio conditions. The effects of walls, ceilings, doors and other obstacles on measurement results would be observed. Chapter one gives a brief introduction to the evolution of UMTS and HSDPA. It goes on to talk about radio wave propagation

  5. Status of air-shower measurements with sparse radio arrays (ARENA 2016)

    CERN Document Server

    Schröder, Frank G

    2016-01-01

    This proceeding gives a summary of the current status and open questions of the radio technique for cosmic-ray air showers, assuming that the reader is already familiar with the principles. It includes recent results of selected experiments not present at this conference, e.g., LOPES and TREND. Current radio arrays like AERA or Tunka-Rex have demonstrated that areas of several km^2 can be instrumented for reasonable costs with antenna spacings of the order of 200 m. For the energy of the primary particle such sparse antenna arrays can already compete in absolute accuracy with other precise techniques, like the detection of air-fluorescence or air-Cherenkov light. With further improvements in the antenna calibration, the radio detection might become even more accurate. For the atmospheric depth of the shower maximum, Xmax, currently only the dense array LOFAR features a precision similar to the fluorescence technique, but analysis methods for the radio measurement of Xmax are still under development. Moreover,...

  6. Measuring the kinetic power of active galactic nuclei in the radio mode

    Science.gov (United States)

    Merloni, Andrea; Heinz, Sebastian

    2007-10-01

    We have studied the relationship among nuclear radio and X-ray power, Bondi rate and the kinetic luminosity of sub-Eddington active galactic nucleus (AGN) jets, as estimated from the pdV work done to inflate the cavities and bubbles observed in the hot X-ray-emitting atmospheres of their host galaxies and clusters. Besides the recently discovered correlation between jet kinetic and Bondi power, we show that a clear correlation exists also between Eddington-scaled kinetic power and bolometric luminosity, given by log(Lkin/LEdd) = (0.49 +/- 0.07) log(Lbol/LEdd) - (0.78 +/- 0.36). The measured slope suggests that these objects are in a radiatively inefficient accretion mode, and have been used to put stringent constraints on the properties of the accretion flow. Interestingly, we found no statistically significant correlations between Bondi power and bolometric AGN luminosity, apart from that induced by their common dependence on Lkin, thus confirming the idea that most of the accretion power emerges from these systems in kinetic form. We have then analysed the relation between kinetic power and radio core luminosity. Combining the measures of jet power with estimators of the unbeamed radio flux of the jet cores as, for example, the so-called Fundamental Plane of active black holes, we are able to determine, in a statistical sense, both the probability distribution of the mean jet Lorentz factor, which peaks at Γm ~ 7, and the intrinsic relationship between kinetic and radio core luminosity (and thus the jet radiative efficiency), which we estimate as logLkin = (0.81 +/- 0.11) logLR + 11.9+4.1-4.4, in good agreement with theoretical predictions of synchrotron jet models. With the aid of these findings, quantitative assessments of kinetic feedback from supermassive black holes in the radio mode (i.e. at low dimensionless accretion rates) will be possible based on accurate determinations of the central engine properties alone, such as mass, radio core and/or X

  7. Measurement of Coherence Bandwidth in UHF Radio Channels for Narrowband Networks

    Directory of Open Access Journals (Sweden)

    Jaroslaw Sadowski

    2015-01-01

    Full Text Available This paper presents results of investigation on the coherence bandwidth of narrowband radio channels in 430 MHz band. The coherence bandwidth values were estimated from a power delay profile obtained by recording CDMA2000 forward channel signals during real-field measurements in various environments: medium city, flat terrain, and hilly terrain in northern Poland. The results of measurements are compared with characteristic parameters of UHF radio channel models defined for exemplary narrowband digital system from the TETRA standard. In all of the tested environments, the coherence bandwidth values during most of an observation time were much higher than 25 kHz. Therefore, the fading in tested UHF narrowband channels should be classified as flat fading.

  8. A Unified Model of the Fermi Bubbles, Microwave Haze, and Polarized Radio Lobes: Reverse Shocks in the Galactic Center's Giant Outflows

    OpenAIRE

    2014-01-01

    The Galactic Center's giant outflows are manifest in three different, non-thermal phenomena: i) the hard-spectrum, \\gamma-ray `Fermi Bubbles' emanating from the nucleus and extending to |b| ~ 50 degrees; ii) the hard-spectrum, total-intensity microwave (~ 20-40 GHz) `Haze' extending to |b| ~ 35 degrees in the lower reaches of the Fermi Bubbles; and iii) the steep spectrum, polarized, `S-PASS' radio (~ 2-20 GHz) Lobes that envelop the Bubbles and extend to |b| ~ 60 degrees. We find that the nu...

  9. Quantum measurement of the degree of polarization of a light beam

    CERN Document Server

    Legré, M; Gisin, Nicolas

    2003-01-01

    We demonstrate a coherent quantum measurement for the determination of the degree of polarization (DOP). This method allows to measure the DOP in the presence of fast polarization state fluctuations, difficult to achieve with the typically used polarimetric technique. A good precision of the DOP measurements is obtained using 8 type II nonlinear crystals assembled for spatial walk-off compensation.

  10. Lunar occultation of the diffuse radio sky: LOFAR measurements between 35 and 80 MHz

    CERN Document Server

    Vedantham, H K; de Bruyn, A G; Wijnholds, S J; Brentjens, M; Abdalla, F B; Asad, K M B; Bernardi, G; Bus, S; Chapman, E; Ciardi, B; Daiboo, S; Fernandez, E R; Ghosh, A; Harker, G; Jelic, V; Jensen, H; Kazemi, S; Lambropoulos, P; Martinez-Rubi, O; Mellema, G; Mevius, M; Offringa, A R; Pandey, V N; Patil, A H; Thomas, R M; Veligatla, V; Yatawatta, S; Zaroubi, S; Anderson, J; Asgekar, A; Bell, M E; Bentum, M J; Best, P; Bonafede, A; Breitling, F; Broderick, J; Brüggen, M; Butcher, H R; Corstanje, A; de Gasperin, F; de Geus, E; Deller, A; Duscha, S; Eislöffel, J; Engels, D; Falcke, H; Fallows, R A; Fender, R; Ferrari, C; Frieswijk, W; Garrett, M A; Grießmeier, J; Gunst, A W; Hassall, T E; Heald, G; Hoeft, M; Hörandel, J; Iacobelli, M; Juette, E; Kondratiev, V I; Kuniyoshi, M; Kuper, G; Mann, G; Markoff, S; McFadden, R; McKay-Bukowski, D; Mulcahy, D D; Munk, H; Nelles, A; Norden, M J; Orru, E; Pandey-Pommier, M; Pizzo, R; Polatidis, A G; Reich, W; Renting, A; Röttgering, H; Schwarz, D; Shulevski, A; Smirnov, O; Stappers, B W; Steinmetz, M; Swinbank, J; Tagger, M; Tang, Y; Tasse, C; ter Veen, S; Thoudam, S; Toribio, C; vocks, C; Wise, M W; Wucknitz, O; Zarka, P

    2014-01-01

    We present radio observations of the Moon between $35$ and $80$ MHz to demonstrate a novel technique of interferometrically measuring large-scale diffuse emission extending far beyond the primary beam (global signal) for the first time. In particular, we show that (i) the Moon appears as a negative-flux source at frequencies $35z>12$) and the Epoch of Reionization ($12>z>5$).

  11. High radio fluxes of PKS2023-07 measured with RATAN-600

    Science.gov (United States)

    Trushkin, S. A.; Nizhelskij, N. A.; Tsybulev, P. G.

    2016-04-01

    After the AGILE detection the gamma-ray flare from the quasar PSK2023-07 (correctly PKS B2022-077) by Piano et al, ATel #8879 we carried out its observations with the RATAN-600 radio telescope SAO RAS. The measured flux densities are equal to 1.50, 1.96, 2.54 Jy at 4.8, 11.2, 21.7 GHz respectively on 1 Apr 2016.

  12. The sensitivity to polarization in stratospheric aerosol retrievals from limb scattered sunlight measurements

    Science.gov (United States)

    Elash, B. J.; Bourassa, A. E.; Rieger, L. A.; Dueck, S. R.; Zawada, D. J.; Degenstein, D. A.

    2017-03-01

    Satellite measurements of limb scattered sunlight at visible and near infrared wavelengths have been used successfully for several years to retrieve the vertical profile of stratospheric aerosol extinction coefficient. The existing satellite measurements are of the total radiance, with very little knowledge or impact of the polarization state of the limb radiance. Recently proposed instrument concepts for stratospheric aerosol profiling have been designed to measure the linearly polarized radiance. Yet, to date, the impact of the polarized measurement on the retrievals has not been systematically studied. Here we use a fully spherical, multiple scattering radiative transfer model to perform a sensitivity study on the effects of the polarized measurement on stratospheric aerosol extinction retrievals through specific investigations of the aerosol signal fraction in polarized measurements, potential retrieval bias, and achievable precision. In this study,we simulate both total and linearly polarized measurements, for a wide range of limb viewing geometries that are encountered in typical low earth orbits and for various aerosol loading scenarios. The orientation of the linear polarization with respect to the horizon is also studied. Taking into account instrument signal to noise levels it is found that in general, the linear polarization can be used as effectively as the total radiance measurement, with consideration of instrument signal to noise capabilities; however the horizontal polarization is more promising in terms of signal magnitude.

  13. An electrodeless system for measurement of liquid sample dielectric properties in radio frequency band.

    Science.gov (United States)

    Hartwig, V; Giovannetti, G; Vanello, N; Costantino, M; Landini, L; Benassi, A

    2006-01-01

    An electrodeless measurement system based on a resonant circuit is proposed for the measurement of dielectric properties of liquid samples at RF (radio frequency). Generally, properties as dielectric constant, loss factor and conductivity are measured by parallel plate capacitor cells: this method has several limitations in the case of particular liquid samples and in the range of radiofrequencies. Our method is based on the measurements of resonance frequency and quality factor of a LC resonant circuit in different measuring conditions, without and with the liquid sample placed inside a test tube around which the home made coil is wrapped. The measurement is performed using a network analyzer and a dual loop probe, inductively coupled with the resonant circuit. One of the advantages of this method is the contactless between the liquid sample and the measurement electrodes. In this paper the measurement system is described and test measurements of conventional liquids dielectric properties are reported.

  14. Quantum measurement corrections to chemically induced dynamic nuclear polarization

    CERN Document Server

    Kominis, I K

    2013-01-01

    Chemically induced dynamic nuclear polarization has emerged as a universal signature of spin order in photosynthetic reaction centers. Such polarization, significantly enhanced above thermal equilibrium, is known to result from the nuclear spin sorting inherent in the radical pair mechanism underlying long-lived charge-separated states in photosynthetic reaction centers. We will here show that the recently understood fundamental quantum dynamics of radical-ion-pair reactions open up a new and completely unexpected venue towards obtaining CIDNP signals. The fundamental decoherence mechanism inherent in the recombination process of radical pairs is shown to produce nuclear spin polarizations on the order of $10^4$ times or more higher than thermal equilibrium values at low fields relevant to natural photosynthesis in earth's magnetic field. This opens up the possibility of a fundamentally new exploration of the biological significance of high nuclear polarizations in photosynthesis.

  15. SPOrt an Experiment Aimed at Measuring the Large Scale Cosmic Microwave Background Polarization

    CERN Document Server

    Carretti, E; Bernardi, G; Cecchini, S; Macculi, C; Sbarra, C; Monari, J; Orfei, A; Poloni, M; Poppi, S; Bölla, G; Bonometto, S A; Gervasi, M; Sironi, G; Zannoni, M; Tucci, M; Baralis, M; Peverini, O A; Tascone, R; Virone, G; Fabbri, R; Nicastro, L; Ng, K W; Razin, V A; Vinyajkin, E N; Sazhin, M V; Strukov, I A

    2002-01-01

    SPOrt (Sky Polarization Observatory) is a space experiment to be flown on the International Space Station during Early Utilization Phase aimed at measuring the microwave polarized emission with FWHM = 7deg, in the frequency range 22-90 GHz. The Galactic polarized emission can be observed at the lower frequencies and the polarization of Cosmic Microwave Background (CMB) at 90 GHz, where contaminants are expected to be less important. The extremely low level of the CMB Polarization signal (< 1 uK) calls for intrinsically stable radiometers. The SPOrt instrument is expressly devoted to CMB polarization measurements and the whole design has been optimized for minimizing instrumental polarization effects. In this contribution we present the receiver architecture based on correlation techniques, the analysis showing its intrinsic stability and the custom hardware development carried out to detect such a low signal.

  16. Measuring c-quark polarization in W + c samples at ATLAS and CMS

    Science.gov (United States)

    Kats, Yevgeny

    2016-11-01

    The process pp → W - c produces polarized charm quarks. The polarization is expected to be partly retained in Λ c baryons when those form in the c-quark hadronization. We argue that it will likely be possible for ATLAS and CMS to measure the Λ c polarization in the W + c samples in Run 2 of the LHC. This can become the first measurement ever of a longitudinal polarization of charm quarks. Its results will provide a unique input to the understanding of polarization transfer in fragmentation. They will also allow applying the same measurement technique to other (e.g., new physics) samples of charm quarks in which the polarization is a priori unknown. The proposed analysis is similar to the ATLAS and CMS measurements of the W + c cross section in the 7 TeV run that used reconstructed D-meson decays for charm tagging.

  17. Lunar occultation of the diffuse radio sky: LOFAR measurements between 35 and 80 MHz

    Science.gov (United States)

    Vedantham, H. K.; Koopmans, L. V. E.; de Bruyn, A. G.; Wijnholds, S. J.; Brentjens, M.; Abdalla, F. B.; Asad, K. M. B.; Bernardi, G.; Bus, S.; Chapman, E.; Ciardi, B.; Daiboo, S.; Fernandez, E. R.; Ghosh, A.; Harker, G.; Jelic, V.; Jensen, H.; Kazemi, S.; Lambropoulos, P.; Martinez-Rubi, O.; Mellema, G.; Mevius, M.; Offringa, A. R.; Pandey, V. N.; Patil, A. H.; Thomas, R. M.; Veligatla, V.; Yatawatta, S.; Zaroubi, S.; Anderson, J.; Asgekar, A.; Bell, M. E.; Bentum, M. J.; Best, P.; Bonafede, A.; Breitling, F.; Broderick, J.; Brüggen, M.; Butcher, H. R.; Corstanje, A.; de Gasperin, F.; de Geus, E.; Deller, A.; Duscha, S.; Eislöffel, J.; Engels, D.; Falcke, H.; Fallows, R. A.; Fender, R.; Ferrari, C.; Frieswijk, W.; Garrett, M. A.; Grießmeier, J.; Gunst, A. W.; Hassall, T. E.; Heald, G.; Hoeft, M.; Hörandel, J.; Iacobelli, M.; Juette, E.; Kondratiev, V. I.; Kuniyoshi, M.; Kuper, G.; Mann, G.; Markoff, S.; McFadden, R.; McKay-Bukowski, D.; McKean, J. P.; Mulcahy, D. D.; Munk, H.; Nelles, A.; Norden, M. J.; Orru, E.; Pandey-Pommier, M.; Pizzo, R.; Polatidis, A. G.; Reich, W.; Renting, A.; Röttgering, H.; Schwarz, D.; Shulevski, A.; Smirnov, O.; Stappers, B. W.; Steinmetz, M.; Swinbank, J.; Tagger, M.; Tang, Y.; Tasse, C.; ter Veen, S.; Thoudam, S.; Toribio, C.; Vocks, C.; Wise, M. W.; Wucknitz, O.; Zarka, P.

    2015-07-01

    We present radio observations of the Moon between 35 and 80 MHz to demonstrate a novel technique of interferometrically measuring large-scale diffuse emission extending far beyond the primary beam (global signal) for the first time. In particular, we show that (i) the Moon appears as a negative-flux source at frequencies 35 specular nature of reflection, and can be independently measured. Our RFI measurements show that (i) Moon-based Cosmic Dawn experiments must design for an Earth-isolation of better than 80 dB to achieve an RFI temperature z > 12) and the Epoch of Reionization (12 > z > 5).

  18. On understanding the figures of merit for detection and measurement of x-ray polarization

    CERN Document Server

    Weisskopf, Martin C; O'Dell, Stephen L

    2010-01-01

    The prospects for accomplishing X-ray polarization measurements appear to have grown in recent years after a more than 35-year hiatus. Unfortunately, this long hiatus has brought with it some confusion over the statistical uncertainties associated with polarization measurements of astronomical sources. The heart of this confusion stems from a misunderstanding (or potential misunderstanding) of a standard figure of merit-the minimum detectable polarization (MDP)-that one of us introduced many years ago. We review the relevant statistics, and quantify the differences between the MDP and the uncertainty of an actual polarization measurement. We discuss the implications for future missions.

  19. Path loss modelling and comparison based on the radio propagation measurement at 3.5GHz

    Institute of Scientific and Technical Information of China (English)

    Wang Ping; Li Yingzhe; Chang Ruoting; Sun Kun; Xu Hui

    2009-01-01

    Wideband IMT-Advanced mobile communication systems tend to operate in the high frequency bands due to a relatively large capacity available. Thus, Measurement and modelling methods of radio propagation characteristics are proposed for the field test of Chinese 4th generation (4G) trial system. The measurement system is established for 3.5GHz based on the sophisticated measurement instruments and the virtual instrument technology. The characteristic parameters of radio propagation such as path loss (PL) exponent and shadow fading standard deviation are extracted from measurement data, which result in the path loss model finally. The comparisons with other existing international models results validate our measurement in terms of path loss model. Based on the analysis of the existing extension model assumed for the microwave frequency at 3.5GHz, we find that the Stanford University Interim (SUI) model fits very well with the measurement result in the hotspot scenario, while the COST 231 model is closer to the measurement result in the suburban scenario. This result provides a measurement-based channel reference for the development of the future IMT-Advanced systems in China.

  20. Laboratory measurements of super-resolving Toraldo pupils for radio astronomical applications

    CERN Document Server

    Olmi, Luca; Cresci, Luca; D'Agostino, Francesco; Migliozzi, Massimo; Mugnai, Daniela; Natale, Enzo; Nesti, Renzo; Panella, Dario; Stefani, Lorenzo

    2016-01-01

    The concept of super-resolution refers to various methods for improving the angular resolution of an optical imaging system beyond the classical diffraction limit. Although several techniques to narrow the central lobe of the illumination Point Spread Function have been developed in optical microscopy, most of these methods cannot be implemented on astronomical telescopes. A possible exception is represented by the variable transmittance filters, also known as "Toraldo Pupils" (TPs) since they were introduced for the first time by G. Toraldo di Francia in 1952. In the microwave range, the first successful laboratory test of TPs was performed in 2003. These first results suggested that TPs could represent a viable approach to achieve super-resolution in Radio Astronomy. We have therefore started a project devoted to a more exhaustive analysis of TPs and how they could be implemented on a radio telescope. In the present work we report on the results of extensive microwave measurements, using TPs with different ...

  1. Spirally polarized beams for polarimetry measurements of deterministic and homogeneous samples

    Science.gov (United States)

    de Sande, Juan Carlos González; Santarsiero, Massimo; Piquero, Gemma

    2017-04-01

    The use of spirally polarized beams (SPBs) in polarimetric measurements of homogeneous and deterministic samples is proposed. Since across any transverse plane such beams present all possible linearly polarized states at once, the complete Mueller matrix of deterministic samples can be recovered with a reduced number of measurements and small errors. Furthermore, SPBs present the same polarization pattern across any transverse plane during propagation, and the same happens for the field propagated after the sample, so that both the sample plane and the plane where the polarization of the field is measured can be chosen at will. Experimental results are presented for the particular case of an azimuthally polarized beam and samples consisting of rotated retardation plates and linear polarizers.

  2. The effect of airborne dust on astronomical polarization measurements

    Science.gov (United States)

    Bailey, Jeremy; Ulanowski, Z.; Lucas, P. W.; Hough, J. H.; Hirst, E.; Tamura, M.

    2008-05-01

    In the past, it has generally been assumed that polarization observations made with ground-based telescopes are unaffected by the passage of light through the Earth's atmosphere. Here, we report observations with a new high-sensitivity astronomical polarimeter (PlanetPol) made during a Saharan dust event over the La Palma observatory in 2005 May that show excess linear polarization in the horizontal direction due to the passage of the starlight through the dust. The polarization reached a maximum value of 4.8 × 10-5 at 56° zenith distance and varied over five nights in proportion to the change in dust optical depth. Polarization of transmitted light (dichroism) does not occur for spherical or randomly oriented non-spherical particles. Thus, these results imply that some fraction of the dust grain population aligns with a preferred orientation. We use T-matrix models to demonstrate that the observed polarization direction implies a vertical orientation for the long axis of the particles. We suggest a possible mechanism for vertical orientation resulting from the electric field in the atmosphere. These results will need to be taken into account in the design and use of future instruments for high-sensitivity astronomical polarimetry. The results also indicate possible new approaches to studying aerosol particles and their effects on the Earth's atmosphere.

  3. Measurement of polarization of cumulative protons in the reaction. gamma. A. -->. pX

    Energy Technology Data Exchange (ETDEWEB)

    Avakyan, R.A.; Avakyan, E.O.; Avetisyan, A.; Asatryan, R.A.; Gavalyan, V.G.; Garibyan, Y.A.; Danagulyan, S.S.; Eganov, V.S.; Keropyan, I.A.; Marukyan, G.O.

    1985-09-01

    Polarization of cumulative protons in the reaction ..gamma..A..-->..pX has been measured in the 190--270 MeV proton energy range for the nuclei C, Cu, Sn, and Pb. The measured polarization is practically independent of the mass number of the nucleus and of the proton energy.

  4. Systematic errors in cosmic microwave background polarization measurements

    CERN Document Server

    O'Dea, D; Johnson, B R; Dea, Daniel O'; Challinor, Anthony

    2006-01-01

    We investigate the impact of instrumental systematic errors on the potential of cosmic microwave background polarization experiments targeting primordial B-modes. To do so, we introduce spin-weighted Muller matrix-valued fields describing the linear response of the imperfect optical system and receiver, and give a careful discussion of the behaviour of the induced systematic effects under rotation of the instrument. We give the correspondence between the matrix components and known optical and receiver imperfections, and compare the likely performance of pseudo-correlation receivers and those that modulate the polarization with a half-wave plate. The latter is shown to have the significant advantage of not coupling the total intensity into polarization for perfect optics, but potential effects like optical distortions that may be introduced by the quasi-optical wave plate warrant further investigation. A fast method for tolerancing time-invariant systematic effects is presented, which propagates errors throug...

  5. Polarization measurement of Cs using the pump laser beam

    CERN Document Server

    Fang, Jiancheng; Duan, Lihong; Fan, Wenfeng; Jiang, Liwei

    2015-01-01

    In the optical pumping systems based on the pump-probe arrangement, the spin polarization of the atoms is generally monitored utilizing the probe laser beam, in which way an extra perturbation must be introduced and thus affects the normal operation of the sensors. By investigating the absorption rate of the circularly polarized pump laser, here we demonstrate the feasibility of extracting the electron-spin polarization from the transmitted pump laser intensity. We experimentally validate the method in a spin-exchange relaxation free (SERF) magnetometer and the results are in excellent agreement with the theory. The scheme operates in a silent mode and features a real-time observation. We also study the corresponding magnetic field response of the SERF magnetometer and a term arising from the diffusion effects has been added to the original model to explain the discrepancy of the response.

  6. High resolution kilometric range optical telemetry in air by radio frequency phase measurement

    Energy Technology Data Exchange (ETDEWEB)

    Guillory, Joffray; García-Márquez, Jorge; Truong, Daniel; Wallerand, Jean-Pierre [Laboratoire Commun de Métrologie LNE-Cnam (LCM), LNE, 1 rue Gaston Boissier, 75015 Paris (France); Šmíd, Radek [Laboratoire Commun de Métrologie LNE-Cnam (LCM), LNE, 1 rue Gaston Boissier, 75015 Paris (France); Institute of Scientific Instruments of the CAS, Kralovopolska 147, 612 64 Brno (Czech Republic); Alexandre, Christophe [Centre d’Études et de Recherche en Informatique et Communications (CEDRIC), Cnam, 292 rue St-Martin, 75003 Paris (France)

    2016-07-15

    We have developed an optical Absolute Distance Meter (ADM) based on the measurement of the phase accumulated by a Radio Frequency wave during its propagation in the air by a laser beam. In this article, the ADM principle will be described and the main results will be presented. In particular, we will emphasize how the choice of an appropriate photodetector can significantly improve the telemeter performances by minimizing the amplitude to phase conversion. Our prototype, tested in the field, has proven its efficiency with a resolution better than 15 μm for a measurement time of 10 ms and distances up to 1.2 km.

  7. Spectrum Measurement and Analysis of TV Band in Support of Cognitive Radio Operation in India

    DEFF Research Database (Denmark)

    Patil, Kishor P.; Skouby, Knud Erik; Prasad, Ramjee

    2013-01-01

    have estimated the spectrum utilization of TV band in Pune, India. We have designed the measurement set up and methodology for the measurement campaign. Our spectrum occupancy analysis provides the realistic view on the spectrum opportunities in India for (i) spectrum refarming of TV band; (ii......) Cognitive Radio operation in TV band. Also we have stressed on the need of quantitative analysis of TVWSs availability and compatibility studies for protection of incumbent services for CR access of TVWSs in India. Also this paper reviews the state-of-the-art in standardization of cognitive access to TVWS....

  8. High resolution kilometric range optical telemetry in air by radio frequency phase measurement

    Science.gov (United States)

    Guillory, Joffray; Šmíd, Radek; García-Márquez, Jorge; Truong, Daniel; Alexandre, Christophe; Wallerand, Jean-Pierre

    2016-07-01

    We have developed an optical Absolute Distance Meter (ADM) based on the measurement of the phase accumulated by a Radio Frequency wave during its propagation in the air by a laser beam. In this article, the ADM principle will be described and the main results will be presented. In particular, we will emphasize how the choice of an appropriate photodetector can significantly improve the telemeter performances by minimizing the amplitude to phase conversion. Our prototype, tested in the field, has proven its efficiency with a resolution better than 15 μm for a measurement time of 10 ms and distances up to 1.2 km.

  9. Low-noise correlation measurements based on software-defined-radio receivers and cooled microwave amplifiers

    Science.gov (United States)

    Nieminen, Teemu; Lähteenmäki, Pasi; Tan, Zhenbing; Cox, Daniel; Hakonen, Pertti J.

    2016-11-01

    We present a microwave correlation measurement system based on two low-cost USB-connected software defined radio dongles modified to operate as coherent receivers by using a common local oscillator. Existing software is used to obtain I/Q samples from both dongles simultaneously at a software tunable frequency. To achieve low noise, we introduce an easy low-noise solution for cryogenic amplification at 600-900 MHz based on single discrete HEMT with 21 dB gain and 7 K noise temperature. In addition, we discuss the quantization effects in a digital correlation measurement and determination of optimal integration time by applying Allan deviation analysis.

  10. Measurement of the nuclear polarization of hydrogen and deuterium molecules using a Lamb-shift polarimeter

    Energy Technology Data Exchange (ETDEWEB)

    Engels, Ralf, E-mail: r.w.engels@fz-juelich.de; Gorski, Robert; Grigoryev, Kiril; Mikirtychyants, Maxim; Rathmann, Frank; Seyfarth, Hellmut; Ströher, Hans; Weiss, Philipp [Institut für Kernphysik, Forschungszentrum Jülich, Wilhelm-Johnen-Str. 1, 52428 Jülich (Germany); Kochenda, Leonid; Kravtsov, Peter; Trofimov, Viktor; Tschernov, Nikolay; Vasilyev, Alexander; Vznuzdaev, Marat [Laboratory of Cryogenic and Superconductive Technique, Petersburg Nuclear Physics Institute, Orlova Roscha 1, 188300 Gatchina (Russian Federation); Schieck, Hans Paetz gen. [Institut für Kernphysik, Universität zu Köln, Zülpicher Str. 77, 50937 Köln (Germany)

    2014-10-15

    Lamb-shift polarimeters are used to measure the nuclear polarization of protons and deuterons at energies of a few keV. In combination with an ionizer, the polarization of hydrogen and deuterium atoms was determined after taking into account the loss of polarization during the ionization process. The present work shows that the nuclear polarization of hydrogen or deuterium molecules can be measured as well, by ionizing the molecules and injecting the H{sub 2}{sup +} (or D{sub 2}{sup +}) ions into the Lamb-shift polarimeter.

  11. Towards Measurement of Polarization Properties of Skin using the Ellipsometry Technique

    Directory of Open Access Journals (Sweden)

    Pejhman Ghassemi

    2009-03-01

    Full Text Available Introduction: The human skin is an active medium from the optical point of view. Therefore, the diagnostic and therapeutic techniques employing light are increasing. Current optical techniques are based on the measurement of the intensity of reflected absorbed or backscattered light from or within skin. Studies have shown that biological tissues, and in particular skin, demonstrate polarization properties. Scattering of light from the surface of skin or the layers within it is a function of incident polarization. Therefore, by changing the polarization of the incident light and measuring the backscattered light, we can study those skin properties which affect the state of polarization. Material and methods: We have implemented a scattering ellipsometry system in order to investigate the polarization properties of a phantom representing skin. Using the Stocks vector defining the state of polarization and measuring the elements of the Mueller matrix representing the phantom under study, we have shown that by changing the reflection and scattering properties of the sample, polarization characteristics of the backscattered light will be affected. Results: The results of this investigation showed that some elements of the Mueller matrix of the phantom under study were affected by the polarization state of the incident light and the scattering component within the phantom. Therefore, these elements have the potential of being used as polarization markers of the biological tissue. Discussion and conclusion: Upon interaction of polarized light with the skin tissue, the backscattered light will contain optical and polarization information about the skin. Using a simple laboratory-made phantom, we have shown that by analyzing the polarization information within the backscattered light we can study the cause, and possibly the disease, which affected the polarization characteristics of the skin.

  12. The shape of the radio wavefront of extensive air showers as measured with LOFAR

    CERN Document Server

    Corstanje, A; Nelles, A; Buitink, S; Enriquez, J E; Falcke, H; Frieswijk, W; Hörandel, J R; Krause, M; Rachen, J P; Scholten, O; ter Veen, S; Thoudam, S; Trinh, G; Akker, M van den; Alexov, A; Anderson, J; Avruch, I M; Bell, M E; Bentum, M J; Bernardi, G; Best, P; Bonafede, A; Breitling, F; Broderick, J; Butcher, H R; Ciardi, B; de Gasperin, F; de Geus, E; de Vos, M; Duscha, S; Eislöffel, J; Engels, D; Fallows, R A; Ferrari, C; Garrett, M A; Griessmeier, J; Gunst, A W; Hamaker, J P; Hoeft, M; Horneffer, A; Iacobelli, M; Juette, E; Karastergiou, A; Kohler, J; Kondratiev, V I; Kuniyoshi, M; Kuper, G; Maat, P; Mann, G; McFadden, R; McKay-Bukowski, D; Mevius, M; Munk, H; Norden, M J; Orru, E; Paas, H; Pandey-Pommier, M; Pandey, V N; Pizzo, R; Polatidis, A G; Reich, W; Röttgering, H; Scaife, A M M; Schwarz, D; Smirnov, O; Stewart, A; Swinbank, J; Tagger, M; Tang, Y; Tasse, C; Toribio, C; Vermeulen, R; Vocks, C; van Weeren, R J; Wijnholds, S J; Wucknitz, O; Yatawatta, S; Zarka, P

    2014-01-01

    Extensive air showers, induced by high energy cosmic rays impinging on the Earth's atmosphere, produce radio emission that is measured with the LOFAR radio telescope. As the emission comes from a finite distance of a few kilometers, the incident wavefront is non-planar. A spherical or conical shape of the wavefront has been proposed, but measurements of individual air showers have been inconclusive so far. For a selected high-quality sample of 161 measured extensive air showers, we have reconstructed the wavefront by measuring pulse arrival times to sub-nanosecond accuracy in 200 to 350 individual antennas. For each measured air shower, we have fitted a conical, spherical, and hyperboloid shape to the arrival times. The fit quality and a likelihood analysis show that a hyperboloid is the best parametrization. Using a non-planar wavefront shape gives an improved angular resolution, when reconstructing the shower arrival direction. Furthermore, a dependence of the wavefront shape on the shower geometry can be s...

  13. Measurement of top quark polarization in t t ¯ lepton +jets final states

    Science.gov (United States)

    Abazov, V. M.; Abbott, B.; Acharya, B. S.; Adams, M.; Adams, T.; Agnew, J. P.; Alexeev, G. D.; Alkhazov, G.; Alton, A.; Askew, A.; Atkins, S.; Augsten, K.; Aushev, V.; Aushev, Y.; Avila, C.; Badaud, F.; Bagby, L.; Baldin, B.; Bandurin, D. V.; Banerjee, S.; Barberis, E.; Baringer, P.; Bartlett, J. F.; Bassler, U.; Bazterra, V.; Bean, A.; Begalli, M.; Bellantoni, L.; Beri, S. B.; Bernardi, G.; Bernhard, R.; Bertram, I.; Besançon, M.; Beuselinck, R.; Bhat, P. C.; Bhatia, S.; Bhatnagar, V.; Blazey, G.; Blessing, S.; Bloom, K.; Boehnlein, A.; Boline, D.; Boos, E. E.; Borissov, G.; Borysova, M.; Brandt, A.; Brandt, O.; Brochmann, M.; Brock, R.; Bross, A.; Brown, D.; Bu, X. B.; Buehler, M.; Buescher, V.; Bunichev, V.; Burdin, S.; Buszello, C. P.; Camacho-Pérez, E.; Casey, B. C. K.; Castilla-Valdez, H.; Caughron, S.; Chakrabarti, S.; Chan, K. M.; Chandra, A.; Chapon, E.; Chen, G.; Cho, S. W.; Choi, S.; Choudhary, B.; Cihangir, S.; Claes, D.; Clutter, J.; Cooke, M.; Cooper, W. E.; Corcoran, M.; Couderc, F.; Cousinou, M.-C.; Cuth, J.; Cutts, D.; Das, A.; Davies, G.; de Jong, S. J.; De La Cruz-Burelo, E.; Déliot, F.; Demina, R.; Denisov, D.; Denisov, S. P.; Desai, S.; Deterre, C.; DeVaughan, K.; Diehl, H. T.; Diesburg, M.; Ding, P. F.; Dominguez, A.; Dubey, A.; Dudko, L. V.; Duperrin, A.; Dutt, S.; Eads, M.; Edmunds, D.; Ellison, J.; Elvira, V. D.; Enari, Y.; Evans, H.; Evdokimov, A.; Evdokimov, V. N.; Fauré, A.; Feng, L.; Ferbel, T.; Fiedler, F.; Filthaut, F.; Fisher, W.; Fisk, H. E.; Fortner, M.; Fox, H.; Franc, J.; Fuess, S.; Garbincius, P. H.; Garcia-Bellido, A.; García-González, J. A.; Gavrilov, V.; Geng, W.; Gerber, C. E.; Gershtein, Y.; Ginther, G.; Gogota, O.; Golovanov, G.; Grannis, P. D.; Greder, S.; Greenlee, H.; Grenier, G.; Gris, Ph.; Grivaz, J.-F.; Grohsjean, A.; Grünendahl, S.; Grünewald, M. W.; Guillemin, T.; Gutierrez, G.; Gutierrez, P.; Haley, J.; Han, L.; Harder, K.; Harel, A.; Hauptman, J. M.; Hays, J.; Head, T.; Hebbeker, T.; Hedin, D.; Hegab, H.; Heinson, A. P.; Heintz, U.; Hensel, C.; Heredia-De La Cruz, I.; Herner, K.; Hesketh, G.; Hildreth, M. D.; Hirosky, R.; Hoang, T.; Hobbs, J. D.; Hoeneisen, B.; Hogan, J.; Hohlfeld, M.; Holzbauer, J. L.; Howley, I.; Hubacek, Z.; Hynek, V.; Iashvili, I.; Ilchenko, Y.; Illingworth, R.; Ito, A. S.; Jabeen, S.; Jaffré, M.; Jayasinghe, A.; Jeong, M. S.; Jesik, R.; Jiang, P.; Johns, K.; Johnson, E.; Johnson, M.; Jonckheere, A.; Jonsson, P.; Joshi, J.; Jung, A. W.; Juste, A.; Kajfasz, E.; Karmanov, D.; Katsanos, I.; Kaur, M.; Kehoe, R.; Kermiche, S.; Khalatyan, N.; Khanov, A.; Kharchilava, A.; Kharzheev, Y. N.; Kiselevich, I.; Kohli, J. M.; Kozelov, A. V.; Kraus, J.; Kumar, A.; Kupco, A.; Kurča, T.; Kuzmin, V. A.; Lammers, S.; Lebrun, P.; Lee, H. S.; Lee, S. W.; Lee, W. M.; Lei, X.; Lellouch, J.; Li, D.; Li, H.; Li, L.; Li, Q. Z.; Lim, J. K.; Lincoln, D.; Linnemann, J.; Lipaev, V. V.; Lipton, R.; Liu, H.; Liu, Y.; Lobodenko, A.; Lokajicek, M.; Lopes de Sa, R.; Luna-Garcia, R.; Lyon, A. L.; Maciel, A. K. A.; Madar, R.; Magaña-Villalba, R.; Malik, S.; Malyshev, V. L.; Mansour, J.; Martínez-Ortega, J.; McCarthy, R.; McGivern, C. L.; Meijer, M. M.; Melnitchouk, A.; Menezes, D.; Mercadante, P. G.; Merkin, M.; Meyer, A.; Meyer, J.; Miconi, F.; Mondal, N. K.; Mulhearn, M.; Nagy, E.; Narain, M.; Nayyar, R.; Neal, H. A.; Negret, J. P.; Neustroev, P.; Nguyen, H. T.; Nunnemann, T.; Orduna, J.; Osman, N.; Pal, A.; Parashar, N.; Parihar, V.; Park, S. K.; Partridge, R.; Parua, N.; Patwa, A.; Penning, B.; Perfilov, M.; Peters, Y.; Petridis, K.; Petrillo, G.; Pétroff, P.; Pleier, M.-A.; Podstavkov, V. M.; Popov, A. V.; Prewitt, M.; Price, D.; Prokopenko, N.; Qian, J.; Quadt, A.; Quinn, B.; Ratoff, P. N.; Razumov, I.; Ripp-Baudot, I.; Rizatdinova, F.; Rominsky, M.; Ross, A.; Royon, C.; Rubinov, P.; Ruchti, R.; Sajot, G.; Sánchez-Hernández, A.; Sanders, M. P.; Santos, A. S.; Savage, G.; Savitskyi, M.; Sawyer, L.; Scanlon, T.; Schamberger, R. D.; Scheglov, Y.; Schellman, H.; Schott, M.; Schwanenberger, C.; Schwienhorst, R.; Sekaric, J.; Severini, H.; Shabalina, E.; Shary, V.; Shaw, S.; Shchukin, A. A.; Shkola, O.; Simak, V.; Skubic, P.; Slattery, P.; Snow, G. R.; Snow, J.; Snyder, S.; Söldner-Rembold, S.; Sonnenschein, L.; Soustruznik, K.; Stark, J.; Stefaniuk, N.; Stoyanova, D. A.; Strauss, M.; Suter, L.; Svoisky, P.; Titov, M.; Tokmenin, V. V.; Tsai, Y.-T.; Tsybychev, D.; Tuchming, B.; Tully, C.; Uvarov, L.; Uvarov, S.; Uzunyan, S.; Van Kooten, R.; van Leeuwen, W. M.; Varelas, N.; Varnes, E. W.; Vasilyev, I. A.; Verkheev, A. Y.; Vertogradov, L. S.; Verzocchi, M.; Vesterinen, M.; Vilanova, D.; Vokac, P.; Wahl, H. D.; Wang, M. H. L. S.; Warchol, J.; Watts, G.; Wayne, M.; Weichert, J.; Welty-Rieger, L.; Williams, M. R. J.; Wilson, G. W.; Wobisch, M.; Wood, D. R.; Wyatt, T. R.; Xie, Y.; Yamada, R.; Yang, S.; Yasuda, T.; Yatsunenko, Y. A.; Ye, W.; Ye, Z.; Yin, H.; Yip, K.; Youn, S. W.; Yu, J. M.; Zennamo, J.; Zhao, T. G.; Zhou, B.; Zhu, J.; Zielinski, M.; Zieminska, D.; Zivkovic, L.; D0 Collaboration

    2017-01-01

    We present a measurement of top quark polarization in t t ¯ pair production in p p ¯ collisions at √{s }=1.96 TeV using data corresponding to 9.7 fb-1 of integrated luminosity recorded with the D0 detector at the Fermilab Tevatron Collider. We consider final states containing a lepton and at least three jets. The polarization is measured through the distribution of lepton angles along three axes: the beam axis, the helicity axis, and the transverse axis normal to the t t ¯ production plane. This is the first measurement of top quark polarization at the Tevatron using lepton +jet final states and the first measurement of the transverse polarization in t t ¯ production. The observed distributions are consistent with standard model predictions of nearly no polarization.

  14. CTS attenuation and cross-polarization measurements at 11.7 GHz

    Science.gov (United States)

    Vogel, W. J.; Straiton, A. W.

    1977-01-01

    The results of data obtained 80 days preceding the solar eclipse shutdown of the CTS 11.7 GHz righthand circularly polarized beacon transmitter are presented. Attenuation and cross polarization isolation were measured. It was determined that depolarization presents a serious limitation to satellite system reliability when frequency reuse by polarization diversity is employed. A 27 db isolation margin would reduce reliability below 99.95%. For the same percentage the required fade margin was below 3 db.

  15. MgII Linear Polarization Measurements Using the MSFC Solar Ultraviolet Magnetograph

    Science.gov (United States)

    West, Edward; Cirtain, Jonathan; Kobayahsi, Ken; Davis, John; Gary, Allen; Adams, Mitzi

    2011-01-01

    This paper will describe the Marshall Space Flight Center's Solar Ultraviolet Magnetograph (SUMI) sounding rocket program, with emphasis on the polarization characteristics of the VUV optics and their spectral, spatial and polarization resolution. SUMI's first flight (7/30/2010) met all of its mission success criteria and this paper will describe the data that was acquired with emphasis on the MgII linear polarization measurements.

  16. MgII Linear Polarization Measurements Using the MSFC Solar Ultraviolet Magnetograph Sounding Rocket

    Science.gov (United States)

    West, Edward; Cirtain, Jonathan; Kobayashi, Ken; Davis, John; Gary, Allen

    2011-01-01

    This paper will describe the Marshall Space Flight Center's Solar Ultraviolet Magnetograph Investigation (SUMI) sounding rocket program, with emphasis on the polarization characteristics of the VUV optics and their spectral, spatial and polarization resolution. SUMI's first flight (7/30/2010) met all of its mission success criteria and this paper will describe the data that was acquired with emphasis on the MgII linear polarization measurements.

  17. Measurements of radio propagation in rock salt for the detection of high-energy neutrinos

    Science.gov (United States)

    Connolly, Amy; Goodhue, Abigail; Miki, Christian; Nichol, Ryan; Saltzberg, David

    2009-02-01

    We present measurements of the transmission of radio/microwave pulses through salt in the Cote Blanche salt mine operated by the North American Salt Company in St. Mary Parish, Louisiana. These results are from data taken in the southwestern region of the 1500 ft (457 m) deep level of the mine on our third and most recent visit to the mine. We transmitted and received a fast, high-power, broadband pulse from within three vertical boreholes that were drilled to depths of 100 ft (30 m) and 200 ft below the 1500 ft level using three different pairs of dipole antennas whose bandwidths span 125-900 MHz. By measuring the relative strength of the received pulses between boreholes with separations of 50 and 169 m, we deduce the attenuation of the signal attributed to the salt medium. We fit the frequency dependence of the attenuation to a power law and find the best fit field attenuation lengths to be 93±7m at 150 MHz, 63±3m at 300 MHz, and 36±2m at 800 MHz. This is the most precise measurement of radio attenuation in a natural salt formation to date. We assess the implications of this measurement for a future neutrino detector in salt.

  18. Comparing LOPES measurements of air-shower radio emission with REAS 3.11 and CoREAS simulations

    CERN Document Server

    Apel, W D; Bähren, L; Bekk, K; Bertaina, M; Biermann, P L; Blümer, J; Bozdog, H; Brancus, I M; Chiavassa, A; Daumiller, K; de Souza, V; Di Pierro, F; Doll, P; Engel, R; Falcke, H; Fuchs, B; Fuhrmann, D; Gemmeke, H; Grupen, C; Haungs, A; Heck, D; Hörandel, J R; Horneffer, A; Huber, D; Huege, T; Isar, P G; Kampert, K -H; Kang, D; Krömer, O; Kuijpers, J; Link, K; Luczak, P; Ludwig, M; Mathes, H J; Melissas, M; Morello, C; Oehlschläger, J; Palmieri, N; Pierog, T; Rautenberg, J; Rebel, H; Roth, M; Rühle, C; Saftoiu, A; Schieler, H; Schmidt, A; Schröder, F G; Sima, O; Toma, G; Trinchero, G C; Weindl, A; Wochele, J; Zabierowski, J; Zensus, J A

    2013-01-01

    Cosmic ray air showers emit radio pulses at MHz frequencies, which can be measured with radio antenna arrays - like LOPES at the Karlsruhe Institute of Technology in Germany. To improve the understanding of the radio emission, we test theoretical descriptions with measured data. The observables used for these tests are the absolute amplitude of the radio signal, and the shape of the radio lateral distribution. We compare lateral distributions of more than 500 LOPES events with two recent and public Monte Carlo simulation codes, REAS 3.11 and CoREAS (v 1.0). The absolute radio amplitudes predicted by REAS 3.11 are in good agreement with the LOPES measurements. The amplitudes predicted by CoREAS are lower by a factor of two, and marginally compatible with the LOPES measurements within the systematic scale uncertainties. In contrast to any previous versions of REAS, REAS 3.11 and CoREAS now reproduce the shape of the measured lateral distributions correctly. This reflects a remarkable progress compared to the si...

  19. Remote beating of parallel or orthogonally polarized dual-wavelength optical carriers for 5G millimeter-wave radio-over-fiber link.

    Science.gov (United States)

    Wang, Huai-Yung; Chi, Yu-Chieh; Lin, Gong-Ru

    2016-08-08

    A novel millimeter-wave radio over fiber (MMW-RoF) link at carrier frequency of 35-GHz is proposed with the use of remotely beating MMW generation from reference master and injected slave colorless laser diode (LD) carriers at orthogonally polarized dual-wavelength injection-locking. The slave colorless LD supports lasing one of the dual-wavelength master modes with orthogonal polarizations, which facilitates the single-mode direct modulation of the quadrature amplitude modulation (QAM) orthogonal frequency division multiplexing (OFDM) data. Such an injected single-carrier encoding and coupled dual-carrier transmission with orthogonal polarization effectively suppresses the cross-heterodyne mode-beating intensity noise, the nonlinear modulation (NLM) and four-wave mixing (FWM) sidemodes during injection locking and fiber transmission. In 25-km single-mode fiber (SMF) based wireline system, the dual-carrier under single-mode encoding provides baseband 24-Gbit/s 64-QAM OFDM transmission with an error vector magnitude (EVM) of 8.8%, a bit error rate (BER) of 3.7 × 10-3, a power penalty of wireless transmission, the beat MMW carrier at 35 GHz can deliver the passband 16-QAM OFDM at 4 Gbit/s to show corresponding EVM and BER of 15.5% and 1.4 × 10-3, respectively, after 25-km SMF and 1.6-m free-space transmission.

  20. Polarized digital shearography for simultaneous dual shearing directions measurements

    Science.gov (United States)

    Xie, Xin; Lee, Cheok Peng; Li, Junrui; Zhang, Boyang; Yang, Lianxiang

    2016-08-01

    The selection of the direction of sensitivity for digital shearography is determined by its shearing direction. As a result, directionally shaped defects could be missed in non-destructive testing using a digital shearography system with only one shearing direction. This paper reports a polarized digital shearography system based on two Mach-Zehnder interferometers, which can create two orthogonal shearing directions and record shearograms in the two orthogonal directions simultaneously. The two shearograms are separated from each other by proper polarization design so that no cross interference occurs. The phase maps of the shearograms are generated by spatial phase shift methods through the introduction of different carrier frequencies in the two orthogonal shearograms and use of the Fourier transform method. This enabled simultaneous dual directional non-destructive testing during continuous loading. Theory derivation, spectrum analysis, and non-destructive testing application results are shown in detail.

  1. Rayleigh beacon for measuring the surface profile of a radio telescope.

    Science.gov (United States)

    Padin, S

    2014-12-01

    Millimeter-wavelength Rayleigh scattering from water droplets in a cloud is proposed as a means of generating a bright beacon for measuring the surface profile of a radio telescope. A λ=3  mm transmitter, with an output power of a few watts, illuminating a stratiform cloud, can generate a beacon with the same flux as Mars in 10 GHz bandwidth, but the beacon has a narrow line width, so it is extremely bright. The key advantage of the beacon is that it can be used at any time, and positioned anywhere in the sky, as long as there are clouds.

  2. First simultaneous measurements of thermospheric winds and zonal ion drifts from the Jicamarca Radio Observatory

    Science.gov (United States)

    Meriwether, John; Baker, Brooke; Twork, Greg; Chau, Jorge; Veliz, Oskar; Woodman, Ronald; Hedden, Russell; Hysell, David

    The first simultaneous observations of thermospheric winds and zonal ion drifts have been ob-tained at the Jicamarca Radio Observatory using a new Fabry-Perot interferometer observatory installed on a mountain ridge overlooking the valley where the JRO radar is located. The re-sults show that the neutral winds and ion drifts generally have the same speed and temporal variation characteristics. These results illustrate the simultaneous detection of the midnight temperature maximum as well. The paper will also describe efforts to obtain common volume measurements of thermospheric winds and temperatures utilizing the FPI Arequipa observatory which is located 4 degrees south of the geomagnetic equator.

  3. Depth-resolved measurements with elliptically polarized reflectance spectroscopy.

    Science.gov (United States)

    Bailey, Maria J; Sokolov, Konstantin

    2016-07-01

    The ability of elliptical polarized reflectance spectroscopy (EPRS) to detect spectroscopic alterations in tissue mimicking phantoms and in biological tissue in situ is demonstrated. It is shown that there is a linear relationship between light penetration depth and ellipticity. This dependence is used to demonstrate the feasibility of a depth-resolved spectroscopic imaging using EPRS. The advantages and drawbacks of EPRS in evaluation of biological tissue are analyzed and discussed.

  4. A Measurement of the Recoil Polarization of Electroproduced Λ(1116)

    Energy Technology Data Exchange (ETDEWEB)

    McAleer, Simeon B. [Florida State Univ., Tallahassee, FL (United States)

    2002-01-01

    The CEBAF Large Acceptance Spectrometer at the Thomas Jefferson National Laboratory was used to study the reaction e + p → e' + K+ + Λ(1116) for events where Λ(1116) subsequently decayed via the channel Λ(1116) → p + π-. Data were taken at incident electron beam energies of 2.5, 4.0, and 4.2 GeV during the 1999 E1C run period. They hyperon production spectra span the Q2 range from 0.5 to 2.8 GeV2 and nearly the entire range in the center of mass angles. The proton angular distribution in the Λ(1116) rest frame is used to deduce the recoil polarization of the hyperon, and the W and cos θ$K+\\atop{cm}$ dependence of the recoil polarization will be presented. The data show sizeable negative polarizations for the Λ(1116) as a function of both cos θ$K+\\atop{cm}$ and W.

  5. Optical modeling and polarization calibration for CMB measurements with ACTPol and Advanced ACTPol

    CERN Document Server

    Koopman, Brian; Cho, Hsiao-Mei; Coughlin, Kevin P; Duff, Shannon M; Gallardo, Patricio A; Hasselfield, Matthew; Henderson, Shawn W; Ho, Shuay-Pwu Patty; Hubmayr, Johannes; Irwin, Kent D; Li, Dale; McMahon, Jeff; Nati, Federico; Niemack, Michael D; Newburgh, Laura; Page, Lyman A; Salatino, Maria; Schillaci, Alessandro; Schmitt, Benjamin L; Simon, Sara M; Vavagiakis, Eve M; Ward, Jonathan T; Wollack, Edward J

    2016-01-01

    The Atacama Cosmology Telescope Polarimeter (ACTPol) is a polarization sensitive upgrade to the Atacama Cosmology Telescope. Located at an elevation of 5190 m, ACTPol measures the Cosmic Microwave Background (CMB) temperature and polarization with arcminute-scale angular resolution. Calibration of the detector angles is a critical step in producing maps of the CMB polarization. Polarization angle offsets in the detector calibration can cause leakage in polarization from E to B modes and induce a spurious signal in the EB and TB cross correlations, which eliminates our ability to measure potential cosmological sources of EB and TB signals, such as cosmic birefringence. We present our optical modeling and measurements associated with calibrating the detector angles in ACTPol.

  6. Measurements of the Suitability of Large Rock Salt Formations for Radio Detection of High Energy Neutrinos

    CERN Document Server

    Gorham, P W; Odian, A; Williams, D; Besson, D; Frichter, G; Tantawi, S G; Gorham, Peter; Saltzberg, David; Odian, Allen; Williams, Dawn; Besson, David; Frichter, George; Tantawi, Sami

    2002-01-01

    We have investigated the possibility that large rock salt formations might be suitable as target masses for detection of neutrinos of energies about 10 PeV and above. In neutrino interactions at these energies, the secondary electromagnetic cascade produces a coherent radio pulse well above ambient thermal noise via the Askaryan effect. We describe measurements of radio-frequency attenuation lengths and ambient thermal noise in two salt formations. Measurements in the Waste Isolation Pilot Plant (WIPP), located in an evaporite salt bed in Carlsbad, NM yielded short attenuation lengths, 3-7 m over 150-300 MHz. However, measurements at United Salt's Hockley mine, located in a salt dome near Houston, Texas yielded attenuation lengths in excess of 250 m at similar frequencies. We have also analyzed early ground-penetrating radar data at Hockley mine and have found additional evidence for attenuation lengths in excess of several hundred meters at 440 MHz. We conclude that salt domes, which may individually contain...

  7. Recent results of gluon and sea quark polarization measurements in polarized proton-proton collisions at STAR

    CERN Document Server

    Li, Xuan

    2014-01-01

    The STAR experiment at RHIC is carrying out a comprehensive high-energy spin physics program to understand the internal structure and dynamics of the proton in polarized proton-proton collisions at $\\sqrt{s} = 200$ GeV and $\\sqrt{s} = 500/510$ GeV. STAR has the capability, with nearly full azimuthal coverage, to reconstruct leptons, hadrons and jets in the mid-rapidity region ($|\\eta|<1$). The results for inclusive jet longitudinal double spin asymmetries taken during the 2009 RHIC run indicate the first non-zero gluon contribution ($\\Delta g(x,Q^{2}) / g(x,Q^{2})$) to the proton spin for $0.05measurements of $W^{+/-}$ bosons at $\\sqrt{s} = 500/510$ GeV in polarized proton-proton collisions provide a direct probe of the polarized anti-u and anti-d quark distributions ($\\Delta \\bar{u}(x,Q^{2})$, $\\Delta \\bar{d}(x,Q^{2})$). These results better constrain the polarized gluon and sea quark distributions of the prot...

  8. A Measurement Method of Time Jitter of a Laser Pulse with Respect to the Radio-Frequency Wave Phase in a Photocathode Radio-Frequency Gun

    Institute of Scientific and Technical Information of China (English)

    刘圣广; 李永贵; 王鸣凯

    2002-01-01

    In a photo-cathode radio-frequency (rf) gun, the micro-bunched charge output from the gun is dependent linearly on the laser injection phase, due to the Scottay effect in the process of photoemission and the procedure of the electron longitudinal acceleration. Based on this principle, a new method is proposed, which should be utilized to measure the time jitter between the driving laser pulse and the rf phase with a very high resolution of a few tens of femtoseconds.

  9. Interaction of polar molecules with resonant radio frequency electric fields: imaging of the NO molecular beam splitting.

    Science.gov (United States)

    Cáceres, J O; Morato, M; González Ureña, A

    2006-12-28

    The interaction between a NO supersonic beam and a resonant radio frequency (RF) field is investigated using laser ionization coupled to imaging techniques. It is shown how the resonant interaction leads to a beam splitting of +/-0.2 degrees toward both positive and negative direction perpendicular to the beam propagation axis. This phenomenon is rationalized using a model based on molecular interferences produced by the action of the resonant RF electric field.

  10. Design Studies for Flux and Polarization Measurements of Photons and Positrons for SLAC Proposal E166: An experiment to test polarized positron production in the FFTB (LCC-0107)

    Energy Technology Data Exchange (ETDEWEB)

    Woods, M

    2003-10-02

    We present results from design studies carried out to investigate measurements of the flux, spectrum and polarization of undulator photons for SLAC Proposal E166. A transmission Compton polarimeter is considered for measuring the photon circular polarization. We also present results for measuring the flux and spectrum of positrons produced by the undulator photons in an 0.5X{sub 0} Titanium target. And we present some considerations for use of a transmission Compton polarimeter to measure the circular polarization of bremsstrahlung photons emitted by the polarized positrons in a thin radiator.

  11. Measurement of polarization of τ-leptons produced in Z decays at CMS

    Energy Technology Data Exchange (ETDEWEB)

    Cherepanov, Vladimir; Fluegge, Guenter; Kargoll, Bastian; Nehrkorn, Alexander; Nugent, Ian M.; Perchalla, Lars; Sauerland, Philip; Stahl, Achim [RWTH Aachen Univ. (Germany). III. Physikalisches Inst. B

    2013-07-01

    Extensive measurements of the τ-lepton polarization and its forward-backward asymmetry at the Z resonance have been performed at LEP. Today, the LHC with ∝20 fb{sup -1} recorded provides the large opportunity for testing Standart Model of Electroweak interactions with τ-leptons and measuring forward-backward asymmetry, τ-lepton polarization and its forward-backward asymmetry. The additional challenges at the LHC are the huge QCD background and the unknown τ-lepton energy. First results on τ-lepton polarization measurements at CMS using Z →τ{sub μ}τ{sub 3π} final state are presented.

  12. Device for measurement of power and shape of radio frequency pulses in nuclear magnetic resonance

    Science.gov (United States)

    Pfeffer, M.; Řezníček, R.; Křišťan, P.; Štěpánková, H.

    2012-05-01

    A design of an instrument to measure the power and shape of radio frequency (RF) pulses operating in a broad frequency range is described. The device is capable of measuring the pulse power up to 500 W of both CW and extremely short (˜1 μs) RF pulses of arbitrary period. The pulse envelope can be observed on a logarithmic scale on a corresponding instrument output using an inexpensive storage oscilloscope. The instrument consists of a coaxial measurement head, the RF processing circuits and an AD conversion and display unit. The whole device is based on widely available integrated circuits; thus, good reproducibility and adaptability of the design is ensured. Since the construction is intended to be used in particular (but not solely) in nuclear magnetic resonance spectroscopy, we found it useful to provide a demonstration of two typical usage scenarios. Other application fields may comprise magnetic resonance imaging, radar and laser technology, power amplifier testing, etc.

  13. Inferences from the Distributions of Fast Radio Burst Pulse Widths, Dispersion Measures and Fluences

    CERN Document Server

    Katz, J I

    2015-01-01

    The widths, dispersion measures, dispersion indices and fluences of Fast Radio Bursts (FRB) impose coupled constraints that all models must satisfy. Observation of dispersion indices close to their low density limit of $-2$ sets a model-independent upper bound on the electron density and a lower bound on the size of any dispersive plasma cloud. The non-monotonic dependence of burst widths (after deconvolution of instrumental effects) on dispersion measure excludes the intergalactic medium as the location of scattering that broadens the FRB in time. Temporal broadening far greater than that of pulsars at similar high Galactic latitudes implies that scattering occurs close to the sources, where high densities and strong turbulence are plausible. FRB energetics are consistent with supergiant pulses from young, fast, high-field pulsars at cosmological distances. The distribution of FRB dispersion measures is inconsistent with expanding clouds (such as SNR). It excludes space-limited distributions (such as the loc...

  14. Study on an On-line Measurement System of Corrosion Rate by Linear Polarization Resistance

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Jeon Soo; Lee, Jae Kun; Lee, Jae Bong; Park, Pyl Yang [Korea Electric Power Research Institute, Daejeon (Korea, Republic of)

    2012-04-15

    The linear polarization resistance method is one of the widely used techniques for the corrosion rate monitoring in the water circulating systems of plants. The measurement is simple and rapid, so that a continuous on-line monitoring is possible without any shutdown of plants. A 2-electrode polarization corrosion rate measurement system was installed in a laboratory using a data acquisition board and PC. The signal processing parameters were optimized for the accurate corrosion rate measurement, and the polarization resistance was compensated with the solution resistance measured by the high frequency sine wave signal of an output channel. The precision of corrosion rate data was greatly improved by removing the initial noise signals on measuring the polarization resistance.

  15. American West Tephras – Geomagnetic polarity events redefined through calibration of radio-isotopic and astronomical time

    DEFF Research Database (Denmark)

    Rivera, Tiffany; Storey, Michael

    . Using an astronomically calibrated age for the monitor mineral Fish Canyon sanidine (FCs;28.201 ± 0.046 Ma, Kuiper, et al., 2008), ages of Pleistocene geomagnetic polarity events are reexamined. Of particular interest, the Quaternary mineral dating standard Alder Creek sandine (ACs) is the type locality...... an astronomically relative 40Ar/39Ar age for the eruption and associated Matuyama/Brunhes magnetic polarity transition. Singlecrystal astronomically relative 40Ar/39Ar ages for the Huckleberry Ridge Tuff are indistinguishable from previously determined ages, and provide a degree of confidence in the astronomical...... ACs that reflects the astronomical calibration of FCs and age of the Cobb Mountain polarity event. It is suggested that this 40Ar/39Ar age replace that of Renne, et al. (1998) when using ACs as the monitor in argon age determinations. The research leading to these results has received funding from...

  16. Measurements of Antenna Surface for Millimeter-Wave Space Radio Telescope

    CERN Document Server

    Kamegai, Kazuhisa; Doi, Akihiro; Sato, Eiichi

    2011-01-01

    In the construction of a space radio telescope, it is essential to use materials with a low noise factor and high mechanical robustness for the antenna surface. We present the results of measurements of the reflection performance of two candidates for antenna surface materials for use in a radio telescope installed in a new millimeter-wave astronomical satellite, ASTRO-G. To estimate the amount of degradation caused by fluctuations in the thermal environment in the projected orbit of the satellite, a thermal cycle test was carried out for two candidates, namely, copper foil carbon fiber reinforced plastic (CFRP) and aluminum-coated CFRP. At certain points during the thermal cycle test, the reflection loss of the surfaces was measured precisely by using a radiometer in the 41-45 GHz band. In both candidates, cracks appeared on the surface after the thermal cycle test, where the number density of the cracks increased as the thermal cycle progressed. The reflection loss also increased in proportion to the number...

  17. Lateral Distribution of the Radio Signal in Extensive Air Showers Measured with LOPES

    CERN Document Server

    Apel, W D; Asch, T; Badea, A F; Bähren, L; Bekk, K; Bertaina, M; Biermann, P L; Bluemer, J; Bozdog, H; Brancus, I M; Brueggemann, M; Buchholz, P; Buitink, S; Cantoni, E; Chiavassa, A; Cossavella, F; Daumiller, K; De Souza, V; Di Pierro, F; Doll, P; Engel, R; Falcke, H; Finger, M; Fuhrmann, D; Gemmeke, H; Ghia, P L; Glasstetter, R; Grupen, C; Haungs, A; Heck, D; Hörandel, J R; Horneffer, A; Huege, T; Isar, P G; Kampert, K H; Kang, D; Kickelbick, D; Krömer, O; Kuijpers, J; Lafebre, S; Luczak, P; Ludwig, M; Mathes, H J; Mayer, H J; Melissas, M; Mitrica, B; Morello, C; Navarra, G; Nehls, S; Nigl, A; Oehlschläger, J; Over, S; Palmieri, N; Petcu, M; Pierog, T; Rautenberg, J; Rebel, H; Roth, M; Saftoiu, A; Schieler, H; Schmidt, A; Schroeder, F; Sima, O; Singh, K; Toma, G; Trinchero, G C; Ulrich, H; Weindl, A; Wochele, J; Wommer, M; Zabierowski, J; Zensus, J A

    2009-01-01

    The antenna array LOPES is set up at the location of the KASCADE-Grande extensive air shower experiment in Karlsruhe, Germany and aims to measure and investigate radio pulses from Extensive Air Showers. The coincident measurements allow us to reconstruct the electric field strength at observation level in dependence of general EAS parameters. In the present work, the lateral distribution of the radio signal in air showers is studied in detail. It is found that the lateral distributions of the electric field strengths in individual EAS can be described by an exponential function. For about 20% of the events a flattening towards the shower axis is observed, preferentially for showers with large inclination angle. The estimated scale parameters R0 describing the slope of the lateral profiles range between 100 and 200 m. No evidence for a direct correlation of R0 with shower parameters like azimuth angle, geomagnetic angle, or primary energy can be found. This indicates that the lateral profile is an intrinsic pr...

  18. The Atacama Cosmology Telescope: measuring radio galaxy bias through cross-correlation with lensing

    CERN Document Server

    Allison, Rupert; Sherwin, Blake D; de Bernardis, Francesco; Bond, J Richard; Calabrese, Erminia; Devlin, Mark J; Dunkley, Joanna; Gallardo, Patricio; Henderson, Shawn; Hincks, Adam D; Hlozek, Renee; Jarvis, Matt; Kosowsky, Arthur; Louis, Thibaut; Madhavacheril, Mathew; McMahon, Jeff; Moodley, Kavilan; Naess, Sigurd; Newburgh, Laura; Niemack, Michael D; Page, Lyman A; Partridge, Bruce; Sehgal, Neelima; Spergel, David N; Staggs, Suzanne T; van Engelen, Alexander; Wollack, Edward J

    2015-01-01

    We correlate the positions of radio galaxies in the FIRST survey with the CMB lensing convergence estimated from the Atacama Cosmology Telescope over 470 square degrees to determine the bias of these galaxies. We remove optically cross-matched sources below redshift $z=0.2$ to preferentially select Active Galactic Nuclei (AGN). We measure the angular cross-power spectrum $C_l^{\\kappa g}$ at $4.4\\sigma$ significance in the multipole range $100measurement characterizes the typical halo mass of radio-loud AGN: we find $\\l...

  19. Radio Measurements of the stellar proper motions in the core of the Orion Nebula Cluster

    CERN Document Server

    Dzib, Sergio A; Rodríguez, Luis F; Gómez, Laura; Forbrich, Jan; Menten, Karl M; Kounkel, Marina A; Mioduszewski, Amy J; Hartmann, Lee; Tobin, John J; Rivera, Juana L

    2016-01-01

    Using multi-epoch VLA observations, covering a time baseline of 29.1 years, we have measured the proper motions of 88 young stars with compact radio emission in the core of the Orion Nebula Cluster (ONC) and the neighboring BN/KL region. Our work increases the number of young stars with measured proper motion at radio frequencies by a factor of 2.5 and enables us to perform a better statistical analysis of the kinematics of the region than was previously possible. Most stars (79 out of 88) have proper motions consistent with a Gaussian distribution centered on $\\overline{\\mu_{\\alpha}\\cos{\\delta}}=1.07\\pm0.09\\quad{\\rm mas\\,yr^{-1}}$, and $\\overline{\\mu_{\\delta}}=-0.84\\pm0.16\\quad{\\rm mas\\,yr^{-1}}$, with velocity dispersions of $\\sigma_{\\alpha}=1.08\\pm0.07\\quad{\\rm mas\\,\\,yr^{-1}},$ $\\sigma_{\\delta}=1.27\\pm0.15\\quad{\\rm mas\\,\\,yr^{-1}}$. We looked for organized movements of these stars but found no clear indication of radial expansion/contraction or rotation. The remaining nine stars in our sample show peculia...

  20. Plasma Diagnostics of the Interstellar Medium with Radio Astronomy

    CERN Document Server

    Haverkorn, Marijke

    2013-01-01

    We discuss the degree to which radio propagation measurements diagnose conditions in the ionized gas of the interstellar medium (ISM). The "signal generators" of the radio waves of interest are extragalactic radio sources (quasars and radio galaxies), as well as Galactic sources, primarily pulsars. The polarized synchrotron radiation of the Galactic non-thermal radiation also serves to probe the ISM, including space between the emitting regions and the solar system. Radio propagation measurements provide unique information on turbulence in the ISM as well as the mean plasma properties such as density and magnetic field strength. Radio propagation observations can provide input to the major contemporary questions on the nature of ISM turbulence, such as its dissipation mechanisms and the processes responsible for generating the turbulence on large spatial scales. Measurements of the large scale Galactic magnetic field via Faraday rotation provide unique observational input to theories of the generation of the ...

  1. A Unified Model of the Fermi Bubbles, Microwave Haze, and Polarized Radio Lobes: Reverse Shocks in the Galactic Center’s Giant Outflows

    Science.gov (United States)

    Crocker, Roland M.; Bicknell, Geoffrey V.; Taylor, Andrew M.; Carretti, Ettore

    2015-08-01

    The Galactic center’s giant outflows are manifest in three different, nonthermal phenomena: (1) the hard-spectrum, γ-ray “Fermi bubbles” emanating from the nucleus and extending to | b| ˜ 50^\\circ ; (2) the hard-spectrum, total-intensity microwave (˜20-40 GHz) “haze” extending to | b| ˜ 35^\\circ in the lower reaches of the Fermi bubbles; and (3) the steep-spectrum, polarized, “S-PASS” radio (˜2-20 GHz) lobes that envelop the bubbles and extend to | b| ˜ 60^\\circ . We find that the nuclear outflows inflate a genuine bubble in each Galactic hemisphere that has the classical structure, working outward, of reverse shock, contact discontinuity (CD), and forward shock. Expanding into the finite pressure of the halo and given appreciable cooling and gravitational losses, the CD of each bubble is now expanding only very slowly. We find observational signatures in both hemispheres of giant, reverse shocks at heights of ˜1 kpc above the nucleus; their presence ultimately explains all three of the nonthermal phenomena mentioned above. Synchrotron emission from shock-reaccelerated cosmic-ray electrons explains the spectrum, morphology, and vertical extent of the microwave haze and the polarized radio lobes. Collisions between shock-reaccelerated hadrons and denser gas in cooling condensations that form inside the CD account for most of the bubbles’ γ-ray emissivity. Inverse Compton emission from primary electrons contributes at the 10%-30% level. Our model suggests that the bubbles are signatures of a comparatively weak but sustained nuclear outflow driven by Galactic center star formation over ≳few × 108 yr.

  2. ATS-6 radio beacon electron content measurements at Ootacamund, India, October 1975-July 1976

    Energy Technology Data Exchange (ETDEWEB)

    Bouwer, S.D.; Davies, K.; Donnelly, R.F.; Grubb, R.N.; Jones, J.E.

    1980-03-01

    An atlas of total slant-path columnar electron content data measured between the ATS-6 satellite and Ootacamund, India, a site near the magnetic Equator is presented. Although these measurements were taken during a solar minimum, the general level of flare and geomagnetic activity that occurred during the observation period is summarized. These total content (N(T)) data were derived from the modulation phase (group delay) of a carrier signal transmitted from the geostationary satellite's Radio Beacon Experiment. This atlas contains two data sets: (1) N(T) as 2-min subsamples digitally recorded between 2 October 1975 and 28 January 1976 corrected for ATS-6 pitch maneuvers and (2) N(T) as 15-min subsamples chart recorded between 21 October 1975 and 22 July 1976 but uncorrected for changes in satellite orientation.

  3. The occultation of Mariner 10 by Mercury. [planetary radius and atmospheric radio measurements

    Science.gov (United States)

    Fjeldbo, G.; Kliore, A.; Sweetnam, D.; Esposito, P.; Seidel, B.; Howard, T.

    1976-01-01

    Analysis of Mariner 10 dual-frequency radio-occultation recordings has yielded new information on the radius and atmosphere of Mercury. The ingress measurements, which were conducted near 1.1 deg north latitude and 67.4 deg east longitude on the night side of the planet, gave a value for the radius of 2439.5 + or - 1 km. Egress near 67.6 deg north latitude and 258.4 deg east longitude on the sunlit side yielded a radius of 2439.0 + or - 1 km. The atmospheric measurements showed the electron density to be less than 1000 per cu cm on both sides of the planet. From the latter result one may infer an upper limit to the dayside surface gas density of 1 million molecules per cu cm.

  4. Measurement of Quarkonium Polarization to Probe QCD at the LHC

    CERN Document Server

    Knunz, Valentin Karl; Strauss, Josef

    2015-01-01

    With the first proton-proton collisions in the Large Hadron Collider (LHC) at CERNin 2010, a new era in high energy physics has been initiated. The data collected bythe various experiments open up the possibility to study standard model processes withhigh precision, in new areas of phase space. The LHC provides excellent conditions forstudies of quarkonium production, due to the high quarkonium production rates giventhe high center-of-mass energy and high instantaneous luminosity of the colliding protonbeams. Studies of the production of heavy quarkonium mesons – bound states of a heavyquark and its respective antiquark – are very important to improve our understanding ofhadron formation. Until quite recently, experimental and phenomenological efforts havenot resulted in a satisfactory overall picture of quarkonium production cross sections andquarkonium polarizations.The Compact Muon Solenoid (CMS) detector is ideally suited to study quarkoniumproduction in the experimentally very clean dimuon decay ch...

  5. Reconstruction of the energy and depth of maximum of cosmic-ray air-showers from LOPES radio measurements

    CERN Document Server

    Apel, W D; Bähren, L; Bekk, K; Bertaina, M; Biermann, P L; Blümer, J; Bozdog, H; Brancus, I M; Cantoni, E; Chiavassa, A; Daumiller, K; de Souza, V; Di Pierro, F; Doll, P; Engel, R; Falcke, H; Fuchs, B; Fuhrmann, D; Gemmeke, H; Grupen, C; Haungs, A; Heck, D; Hörandel, J R; Horneffer, A; Huber, D; Huege, T; Isar, P G; Kampert, K -H; Kang, D; Krömer, O; Kuijpers, J; Link, K; Łuczak, P; Ludwig, M; Mathes, H J; Melissas, M; Morello, C; Oehlschläger, J; Palmieri, N; Pierog, T; Rautenberg, J; Rebel, H; Roth, M; Rühle, C; Saftoiu, A; Schieler, H; Schmidt, A; Schröder, F G; Sima, O; Toma, G; Trinchero, G C; Weindl, A; Wochele, J; Zabierowski, J; Zensus, J A

    2014-01-01

    LOPES is a digital radio interferometer located at Karlsruhe Institute of Technology (KIT), Germany, which measures radio emission from extensive air showers at MHz frequencies in coincidence with KASCADE-Grande. In this article, we explore a method (slope method) which leverages the slope of the measured radio lateral distribution to reconstruct crucial attributes of primary cosmic rays. First, we present an investigation of the method on the basis of pure simulations. Second, we directly apply the slope method to LOPES measurements. Applying the slope method to simulations, we obtain uncertainties on the reconstruction of energy and depth of shower maximum Xmax of 13% and 50 g/cm^2, respectively. Applying it to LOPES measurements, we are able to reconstruct energy and Xmax of individual events with upper limits on the precision of 20-25% for the primary energy and 95 g/cm^2 for Xmax, despite strong human-made noise at the LOPES site.

  6. Measuring a Cherenkov ring in the radio emission from air showers at 110-190 MHz with LOFAR

    CERN Document Server

    Nelles, A; Buitink, S; Corstanje, A; de Vries, K D; Enriquez, J E; Falcke, H; Frieswijk, W; Hörandel, J R; Scholten, O; ter Veen, S; Thoudam, S; Akker, M van den; Anderson, J; Asgekar, A; Bell, M E; Bentum, M J; Bernardi, G; Best, P; Bregman, J; Breitling, F; Broderick, J; Brouw, W N; Brüggen, M; Butcher, H R; Ciardi, B; Deller, A; Duscha, S; Eislöffel, J; Fallows, R A; Garrett, M A; Gunst, A W; Hassall, T E; Heald, G; Horneffer, A; Iacobelli, M; Juette, E; Karastergiou, A; Kondratiev, V I; Kramer, M; Kuniyoshi, M; Kuper, G; Maat, P; Mann, G; Mevius, M; Norden, M J; Paas, H; Pandey-Pommier, M; Pietka, G; Pizzo, R; Polatidis, A G; Reich, W; Röttgering, H; Scaife, A M M; Schwarz, D; Smirnov, O; Stapper, B W; Steinmetz, M; Stewart, A; Tagger, M; Tang, Y; Tasse, C; Vermeulen, R; Vocks, C; van Weeren, R J; Wijnholds, S J; Wucknitz, O; Yatawatta, S; Zarka, P

    2014-01-01

    Measuring radio emission from air showers offers a novel way to determine properties of the primary cosmic rays such as their mass and energy. Theory predicts that relativistic time compression effects lead to a ring of amplified emission which starts to dominate the emission pattern for frequencies above ~100 MHz. In this article we present the first detailed measurements of this structure. Ring structures in the radio emission of air showers are measured with the LOFAR radio telescope in the frequency range of 110 - 190 MHz. These data are well described by CoREAS simulations. They clearly confirm the importance of including the index of refraction of air as a function of height. Furthermore, the presence of the Cherenkov ring offers the possibility for a geometrical measurement of the depth of shower maximum, which in turn depends on the mass of the primary particle.

  7. New expansion rate measurements of the Crab Nebula in radio and optical

    CERN Document Server

    Bietenholz, Michael F

    2015-01-01

    We present new radio measurements of the expansion rate of the Crab nebula's synchrotron nebula over a ~30-yr period. We find a convergence date for the radio synchrotron nebula of CE 1255 +- 27. We also re-evaluated the expansion rate of the optical line emitting filaments, and we show that the traditional estimates of their convergence dates are slightly biased. Using an un-biased Bayesian analysis, we find a convergence date for the filaments of CE 1091 +- 34 (~40 yr earlier than previous estimates). Our results show that both the synchrotron nebula and the optical line-emitting filaments have been accelerated since the explosion in CE 1054, but that the synchrotron nebula has been relatively strongly accelerated, while the optical filaments have been only slightly accelerated. The finding that the synchrotron emission expands more rapidly than the filaments supports the picture that the latter are the result of the Rayleigh-Taylor instability at the interface between the pulsar-wind nebula and the surroun...

  8. New expansion rate measurements of the Crab nebula in radio and optical

    Science.gov (United States)

    Bietenholz, M. F.; Nugent, R. L.

    2015-12-01

    We present new radio measurements of the expansion rate of the Crab nebula's synchrotron nebula over a ˜30-yr period. We find a convergence date for the radio synchrotron nebula of CE 1255 ± 27. We also re-evaluated the expansion rate of the optical-line-emitting filaments, and we show that the traditional estimates of their convergence date are slightly biased. Using an unbiased Bayesian analysis, we find a convergence date for the filaments of CE 1091 ± 34 (˜40 yr earlier than previous estimates). Our results show that both the synchrotron nebula and the optical-line-emitting filaments have been accelerated since the explosion in CE 1054, but that the synchrotron nebula has been relatively strongly accelerated, while the optical filaments have been only slightly accelerated. The finding that the synchrotron emission expands more rapidly than the filaments supports the picture that the latter are the result of the Rayleigh-Taylor instability at the interface between the pulsar-wind nebula and the surrounding freely expanding supernova ejecta, and rules out models where the pulsar-wind bubble is interacting directly with the pre-supernova wind of the Crab's progenitor.

  9. Biodegradable X-ray markers of controlled radio-opacity. Temporary position measurements in bone.

    Science.gov (United States)

    Stallmann, Hein P; Faber, Chris; Plokker, Herbert M; Wuisman, Paul I J M

    2005-02-01

    In order to analyze X-ray markers for potential use in biodegradable implants or radiostereogrammatic analysis (RSA), we combined iopromide contrast fluid with biodegradable calcium phosphate cement. The radio-opacity of 10 x 10 mm markers containing different iodine concentrations (0, 120, 240, 360 and 720 mg per gram cement) was compared to an aluminium wedge of increasing (1-10 mm) thickness. The addition of iopromide increased the radio-opacity in a dose-dependent manner, which was comparable to 9-mm aluminium at concentrations of 240-720 mg/g. Radiographs of markers placed in explanted rabbit and in human femora were made to investigate the clinical accuracy for position determination. Markers of 1 x 1 mm (120 mg/g) were clearly discernable in all femora, and could be used to adequately measure distances of 5-45 mm (accuracy 0.10-2.19 mm). These markers might be embedded in biodegradable implants or used as temporary markers in the bone to analyze postoperative position on radiographs.

  10. Measurement of top quark polarization in top-antitop lepton+jets final states at DØ

    Energy Technology Data Exchange (ETDEWEB)

    Augsten, Kamil [Czech Technical Univ., Prague (Czech Republic)

    2017-01-01

    This thesis presents a measurement of the top quark polarization in the $t\\overline{t}$ events produced in $p\\overline{p}$ collisions at $\\sqrt{s}=1.96$ TeV using data corresponding to 9.7 fb$^{-1}$ of integrated luminosity collected with the D0 detector at the Fermilab Tevatron Collider. The final states used in the measurement contain one lepton and at least three jets. The polarization is measured using the angular distribution of leptons along three different axes: the beam axis, the helicity axis, and the transverse axis normal to the $t\\overline{t}$ production plane. This is the first measurement of top quark polarization at the Tevatron Collider in lepton+jets final states, and the first measurement of transverse polarization in $t\\overline{t}$ production. The polarization along the beam axis is combined with the previous result in the dilepton final states by the D0 experiment. The observed distributions are consistent with the Standard Model of nearly no polarization and no indication for beyond Standard Model physics is observed. The measurement offers legacy result from unique Tevatron Collider data and provides more information about the top quark production and decays, about the properties of the heaviest elementary particle.

  11. Absolute Polarization Measurements at RHIC in the Coulomb Nuclear Interference Region

    CERN Document Server

    Eyser, K O; Bravar, A; Bunce, G; Dhawan, S; Gill, R; Haeberli, W; Huang, H; Jinnouchi, O; Makdisi, Y; Nakagawa, I; Nass, A; Okada, H; Stephenson, E; Svirida, D; Wise, T; Wood, J; Zelenski, A

    2007-01-01

    The Relativistic Heavy Ion Collider at Brookhaven National Laboratory provides polarized proton beams for the investigation of the nucleon spin structure. For polarimetry, carbon-proton and proton-proton scattering is used in the Coulomb nuclear interference region at small momentum transfer ($-t$). Fast polarization measurements of each beam are carried out with carbon fiber targets at several times during an accelerator store. A polarized hydrogen gas jet target is needed for absolute normalization over multiple stores, while the target polarization is constantly monitored in a Breit-Rabi polarimeter. In 2005, the jet polarimeter has been used with both RHIC beams. We present results from the jet polarimeter including a detailed analysis of background contributions to asymmetries and to the beam polarization.

  12. Study of Linearly Polarized Light Measuring Fiber Diameter

    Energy Technology Data Exchange (ETDEWEB)

    Liang Hong, E-mail: lianghong@cuc.edu.cn [School of science, Communication University of China 100024 (China)

    2011-02-01

    The letter discusses a new way to measure fiber diameters, studies the theory of measuring fiber radius using this way, carries out numerical simulation based on this and provides experiment method as well.

  13. Measurement of top quark polarization in $t \\overline{t}$ lepton+jets final states

    CERN Document Server

    Abazov, Victor Mukhamedovich; Acharya, Bannanje Sripath; Adams, Mark Raymond; Adams, Todd; Agnew, James P; Alexeev, Guennadi D; Alkhazov, Georgiy D; Alton, Andrew K; Askew, Andrew Warren; Atkins, Scott; Augsten, Kamil; Aushev, Volodymyr; Aushev, Yegor; Avila, Carlos A; Badaud, Frederique; Bagby, Linda F; Baldin, Boris; Bandurin, Dmitry V; Banerjee, Sunanda; Barberis, Emanuela; Baringer, Philip S; Bartlett, JFrederick; Bassler, Ursula Rita; Bazterra, Victor; Bean, Alice L; Begalli, Marcia; Bellantoni, Leo; Beri, Suman B; Bernardi, Gregorio; Bernhard, Ralf Patrick; Bertram, Iain A; Besancon, Marc; Beuselinck, Raymond; Bhat, Pushpalatha C; Bhatia, Sudeep; Bhatnagar, Vipin; Blazey, Gerald Charles; Blessing, Susan K; Bloom, Kenneth A; Boehnlein, Amber S; Boline, Daniel Dooley; Boos, Edward E; Borissov, Guennadi; Borysova, Maryna; Brandt, Andrew; Brandt, Oleg; Brochmann, Michelle; Brock, Raymond L; Bross, Alan D; Brown, Duncan Paul; Bu, Xue-Bing; Buehler, Marc; Buescher, Volker; Bunichev, Viacheslav Yevgenyevich; Burdin, Sergey; Buszello, Claus Peter; Camacho-Perez, Enrique; Casey, Brendan Cameron Kieran; Castilla-Valdez, Heriberto; Caughron, Seth Aaron; Chakrabarti, Subhendu; Chan, Kwok Ming Leo; Chandra, Avdhesh; Chapon, Emilien; Chen, Guo; Cho, Sung-Woong; Choi, Suyong; Choudhary, Brajesh C; Cihangir, Selcuk; Claes, Daniel R; Clutter, Justace Randall; Cooke, Michael P; Cooper, William Edward; Corcoran, Marjorie D; Couderc, Fabrice; Cousinou, Marie-Claude; Cuth, Jakub; Cutts, David; Das, Amitabha; Davies, Gavin John; de Jong, Sijbrand Jan; De La Cruz-Burelo, Eduard; Deliot, Frederic; Demina, Regina; Denisov, Dmitri S; Denisov, Sergei P; Desai, Satish Vijay; Deterre, Cecile; DeVaughan, Kayle Otis; Diehl, HThomas; Diesburg, Michael; Ding, Pengfei; Dominguez, DAaron M; Dubey, Abhinav Kumar; Dudko, Lev V; Duperrin, Arnaud; Dutt, Suneel; Eads, Michael T; Edmunds, Daniel L; Ellison, John A; Elvira, VDaniel; Enari, Yuji; Evans, Harold G; Evdokimov, Anatoly V; Evdokimov, Valeri N; Faure, Alexandre; Feng, Lei; Ferbel, Thomas; Fiedler, Frank; Filthaut, Frank; Fisher, Wade Cameron; Fisk, HEugene; Fortner, Michael R; Fox, Harald; Franc, Jiri; Fuess, Stuart C; Garbincius, Peter H; Garcia-Bellido, Aran; Garcia-Gonzalez, Jose Andres; Gavrilov, Vladimir B; Geng, Weigang; Gerber, Cecilia Elena; Gershtein, Yuri S; Ginther, George E; Gogota, Olga; Golovanov, Georgy Anatolievich; Grannis, Paul D; Greder, Sebastien; Greenlee, Herbert B; Grenier, Gerald Jean; Gris, Phillipe Luc; Grivaz, Jean-Francois; Grohsjean, Alexander; Gruenendahl, Stefan; Gruenewald, Martin Werner; Guillemin, Thibault; Gutierrez, Gaston R; Gutierrez, Phillip; Haley, Joseph Glenn Biddle; Han, Liang; Harder, Kristian; Harel, Amnon; Hauptman, John Michael; Hays, Jonathan M; Head, Tim; Hebbeker, Thomas; Hedin, David R; Hegab, Hatim; Heinson, Ann; Heintz, Ulrich; Hensel, Carsten; Heredia-De La Cruz, Ivan; Herner, Kenneth Richard; Hesketh, Gavin G; Hildreth, Michael D; Hirosky, Robert James; Hoang, Trang; Hobbs, John D; Hoeneisen, Bruce; Hogan, Julie; Hohlfeld, Mark; Holzbauer, Jenny Lyn; Howley, Ian James; Hubacek, Zdenek; Hynek, Vlastislav; Iashvili, Ia; Ilchenko, Yuriy; Illingworth, Robert A; Ito, Albert S; Jabeen, Shabnam; Jaffre, Michel J; Jayasinghe, Ayesh; Jeong, Min-Soo; Jesik, Richard L; Jiang, Peng; Johns, Kenneth Arthur; Johnson, Emily; Johnson, Marvin E; Jonckheere, Alan M; Jonsson, Per Martin; Joshi, Jyoti; Jung, Andreas Werner; Juste, Aurelio; Kajfasz, Eric; Karmanov, Dmitriy Y; Katsanos, Ioannis; Kaur, Manbir; Kehoe, Robert Leo Patrick; Kermiche, Smain; Khalatyan, Norayr; Khanov, Alexander; Kharchilava, Avto; Kharzheev, Yuri N; Kiselevich, Ivan Lvovich; Kohli, Jatinder M; Kozelov, Alexander V; Kraus, James Alexander; Kumar, Ashish; Kupco, Alexander; Kurca, Tibor; Kuzmin, Valentin Alexandrovich; Lammers, Sabine Wedam; Lebrun, Patrice; Lee, Hyeon-Seung; Lee, Seh-Wook; Lee, William M; Lei, Xiaowen; Lellouch, Jeremie; Li, Dikai; Li, Hengne; Li, Liang; Li, Qi-Zhong; Lim, Jeong Ku; Lincoln, Donald W; Linnemann, James Thomas; Lipaev, Vladimir V; Lipton, Ronald J; Liu, Huanzhao; Liu, Yanwen; Lobodenko, Alexandre; Lokajicek, Milos; Lopes de Sa, Rafael; Luna-Garcia, Rene; Lyon, Adam Leonard; Maciel, Arthur KA; Madar, Romain; Magana-Villalba, Ricardo; Malik, Sudhir; Malyshev, Vladimir L; Mansour, Jason; Martinez-Ortega, Jorge; McCarthy, Robert L; Mcgivern, Carrie Lynne; Meijer, Melvin M; Melnitchouk, Alexander S; Menezes, Diego D; Mercadante, Pedro Galli; Merkin, Mikhail M; Meyer, Arnd; Meyer, Jorg Manfred; Miconi, Florian; Mondal, Naba K; Mulhearn, Michael James; Nagy, Elemer; Narain, Meenakshi; Nayyar, Ruchika; Neal, Homer A; Negret, Juan Pablo; Neustroev, Petr V; Nguyen, Huong Thi; Nunnemann, Thomas P; Hernandez Orduna, Jose de Jesus; Osman, Nicolas Ahmed; Pal, Arnab; Parashar, Neeti; Parihar, Vivek; Park, Sung Keun; Partridge, Richard A; Parua, Nirmalya; Patwa, Abid; Penning, Bjoern; Perfilov, Maxim Anatolyevich; Peters, Reinhild Yvonne Fatima; Petridis, Konstantinos; Petrillo, Gianluca; Petroff, Pierre; Pleier, Marc-Andre; Podstavkov, Vladimir M; Popov, Alexey V; Prewitt, Michelle; Price, Darren; Prokopenko, Nikolay N; Qian, Jianming; Quadt, Arnulf; Quinn, Gene Breese; Ratoff, Peter N; Razumov, Ivan A; Ripp-Baudot, Isabelle; Rizatdinova, Flera; Rominsky, Mandy Kathleen; Ross, Anthony; Royon, Christophe; Rubinov, Paul Michael; Ruchti, Randal C; Sajot, Gerard; Sanchez-Hernandez, Alberto; Sanders, Michiel P; Santos, Angelo Souza; Savage, David G; Savitskyi, Mykola; Sawyer, HLee; Scanlon, Timothy P; Schamberger, RDean; Scheglov, Yury A; Schellman, Heidi M; Schott, Matthias; Schwanenberger, Christian; Schwienhorst, Reinhard H; Sekaric, Jadranka; Severini, Horst; Shabalina, Elizaveta K; Shary, Viacheslav V; Shaw, Savanna; Shchukin, Andrey A; Simak, Vladislav J; Skubic, Patrick Louis; Slattery, Paul F; Snow, Gregory R; Snow, Joel Mark; Snyder, Scott Stuart; Soldner-Rembold, Stefan; Sonnenschein, Lars; Soustruznik, Karel; Stark, Jan; Stefaniuk, Nazar; Stoyanova, Dina A; Strauss, Michael G; Suter, Louise; Svoisky, Peter V; Titov, Maxim; Tokmenin, Valeriy V; Tsai, Yun-Tse; Tsybychev, Dmitri; Tuchming, Boris; Tully, Christopher George T; Uvarov, Lev; Uvarov, Sergey L; Uzunyan, Sergey A; Van Kooten, Richard J; van Leeuwen, Willem M; Varelas, Nikos; Varnes, Erich W; Vasilyev, Igor A; Verkheev, Alexander Yurievich; Vertogradov, Leonid S; Verzocchi, Marco; Vesterinen, Mika; Vilanova, Didier; Vokac, Petr; Wahl, Horst D; Wang, Michael HLS; Warchol, Jadwiga; Watts, Gordon Thomas; Wayne, Mitchell R; Weichert, Jonas; Welty-Rieger, Leah Christine; Williams, Mark Richard James; Wilson, Graham Wallace; Wobisch, Markus; Wood, Darien Robert; Wyatt, Terence R; Xie, Yunhe; Yamada, Ryuji; Yang, Siqi; Yasuda, Takahiro; Yatsunenko, Yuriy A; Ye, Wanyu; Ye, Zhenyu; Yin, Hang; Yip, Kin; Youn, Sungwoo; Yu, Jiaming; Zennamo, Joseph; Zhao, Tianqi Gilbert; Zhou, Bing; Zhu, Junjie; Zielinski, Marek; Zieminska, Daria; Zivkovic, Lidija

    2016-01-01

    We present a study of top quark polarization in $t \\overline{t}$ events produced in $p \\overline{p}$ collisions at $\\sqrt{s}=1.96$ TeV. Data correspond to 9.7 fb$^{-1}$ collected with the D0 detector at the Tevatron. We use final states containing a lepton and at least three jets. The polarization is measured using the distribution of leptons along the beam and helicity axes, and the axis normal to the production plane. This is the first measurement of top quark polarization at the Tevatron in $\\ell$+jets final states, and first measurement of transverse polarization in $t \\overline{t}$ production. The observed distributions are consistent with the standard model.

  14. HIGH-RESOLUTION RADIO CONTINUUM MEASUREMENTS OF THE NUCLEAR DISKS OF Arp 220

    Energy Technology Data Exchange (ETDEWEB)

    Barcos-Muñoz, L.; Evans, A. S.; Privon, G. C.; Stierwalt, S. [Department of Astronomy, University of Virginia, 530 McCormick Road, Charlottesville, VA 22904 (United States); Leroy, A. K.; Condon, J.; Reichardt, A. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22904 (United States); Armus, L. [Spitzer Science Center, California Institute of Technology, MC 220-6, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Mazzarella, J. M.; Murphy, E. J. [Infrared Processing and Analysis Center, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States); Meier, D. S. [New Mexico Institute of Mining and Technology, 801 Leroy Place, Socorro, NM 87801 (United States); Momjian, E.; Ott, J. [National Radio Astronomy Observatory, P.O. Box O, 1003 Lopezville Road, Socorro, NM 87801 (United States); Sakamoto, K. [Academia Sinica, Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China); Sanders, D. B. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96816 (United States); Schinnerer, E.; Walter, F. [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Surace, J. A. [Spitzer Science Center, MS 314-6, California Institute of Technology, Pasadena, CA 91125 (United States); Thompson, T. A., E-mail: ldb7et@virginia.edu [Department of Astronomy and Center for Cosmology and Astro-Particle Physics, The Ohio State University, Columbus, OH 43210 (United States)

    2015-01-20

    We present new Karl G. Jansky Very Large Array radio continuum images of the nuclei of Arp 220, the nearest ultra-luminous infrared galaxy. These new images have both the angular resolution to study the detailed morphologies of the two nuclei that power the galaxy merger and sensitivity to a wide range of spatial scales. At 33 GHz, we achieve a resolution of 0.''081 × 0.''063 (29.9 × 23.3 pc) and resolve the radio emission surrounding both nuclei. We conclude from the decomposition of the radio spectral energy distribution that a majority of the 33 GHz emission is synchrotron radiation. The spatial distributions of radio emission in both nuclei are well described by exponential profiles. These have deconvolved half-light radii (R {sub 50d}) of 51 and 35 pc for the eastern and western nuclei, respectively, and they match the number density profile of radio supernovae observed with very long baseline interferometry. This similarity might be due to the fast cooling of cosmic rays electrons caused by the presence of a strong (∼mG) magnetic field in this system. We estimate extremely high molecular gas surface densities of 2.2{sub −1.0}{sup +2.1}×10{sup 5} (east) and 4.5{sub −1.9}{sup +4.5}×10{sup 5} (west) M {sub ☉} pc{sup –2}, corresponding to total hydrogen column densities of N {sub H} = 2.7{sub −1.2}{sup +2.7}×10{sup 25} (east) and 5.6{sub −2.4}{sup +5.5}×10{sup 25} cm{sup –2} (west). The implied gas volume densities are similarly high, n{sub H{sub {sub 2}}}∼3.8{sub −1.6}{sup +3.8}×10{sup 4} (east) and ∼11{sub −4.5}{sup +12}×10{sup 4} cm{sup –3} (west). We also estimate very high luminosity surface densities of Σ{sub IR}∼4.2{sub −0.7}{sup +1.6}×10{sup 13} (east) and Σ{sub IR}∼9.7{sub −2.4}{sup +3.7}×10{sup 13} (west) L{sub ⊙} kpc{sup −2}, and star formation rate surface densities of Σ{sub SFR} ∼ 10{sup 3.7} {sup ±} {sup 0.1} (east) and Σ{sub SFR} ∼ 10{sup 4.1} {sup ±} {sup 0.1}(west) M

  15. Precision measurement of the nuclear polarization in laser-cooled, optically pumped $^{37}\\mathrm{K}$

    CERN Document Server

    Fenker, Benjamin; Melconian, Dan; Anderson, Rhys M A; Anholm, Melissa; Ashery, Daniel; Behling, Richard S; Cohen, Iuliana; Craiciu, Ioana; Donohue, John M; Farfan, Christian; Friesen, Daniel; Gorelov, Alexandre; McNeil, James; Mehlman, Michael; Norton, Heather; Olchanski, Konstantin; Smale, Scott; Theriault, O; Vantyghem, Adrian N; Warner, Claire L

    2016-01-01

    We report a measurement of the nuclear polarization of laser-cooled, optically-pumped $^{37}\\mathrm{K}$ atoms which will allow us to precisely measure angular correlation parameters in the beta-decay of the same atoms. These results will be used to test the $V-A$ framework of the weak interaction at high precision. At the TRIUMF Neutral Atom Trap (TRINAT), a magneto-optical trap (MOT) confines and cools neutral $^{37}\\mathrm{K}$ atoms and optical pumping spin-polarizes them. We monitor the nuclear polarization of the same atoms that are decaying in situ by photoionizing a small fraction of the partially polarized atoms and then use the standard optical Bloch equations to model their population distribution. We obtain an average nuclear polarization of $P = 0.9913\\pm0.0008$, which is significantly more precise than previous measurements with this technique. Since our current measurement of the beta-asymmetry has $0.2\\%$ statistical uncertainty, the polarization measurement reported here will not limit its over...

  16. High-Resolution Group Quantization Phase Processing Method in Radio Frequency Measurement Range.

    Science.gov (United States)

    Du, Baoqing; Feng, Dazheng; Tang, Yaohua; Geng, Xin; Zhang, Duo; Cai, Chaofeng; Wan, Maoquan; Yang, Zhigang

    2016-07-08

    Aiming at the more complex frequency translation, the longer response time and the limited measurement precision in the traditional phase processing, a high-resolution phase processing method by group quantization higher than 100 fs level is proposed in radio frequency measurement range. First, the phase quantization is used as a step value to quantize every phase difference in a group by using the fixed phase relationships between different frequencies signals. The group quantization is formed by the results of the quantized phase difference. In the light of frequency drift mainly caused by phase noise of measurement device, a regular phase shift of the group quantization is produced, which results in the phase coincidence of two comparing signals which obtain high-resolution measurement. Second, in order to achieve the best coincidences pulse, a subtle delay is initiatively used to reduce the width of the coincidences fuzzy area according to the transmission characteristics of the coincidences in the specific medium. Third, a series of feature coincidences pulses of fuzzy area can be captured by logic gate to achieve the best phase coincidences information for the improvement of the measurement precision. The method provides a novel way to precise time and frequency measurement.

  17. Radio Propagation in Open-pit Mines: a First Look at Measurements in the 2.6 GHz Band

    DEFF Research Database (Denmark)

    Portela Lopes de Almeida, Erika; Caldwell, George; Rodriguez Larrad, Ignacio

    2017-01-01

    In this paper we present the results of an extensive measurement campaign performed at two large iron ore mining centers in Brazil at the 2.6 GHz band. Although several studies focusing on radio propagation in underground mines have been published, measurement data and careful analyses for open...

  18. Calibrating high-precision Faraday rotation measurements for LOFAR and the next generation of low-frequency radio telescopes

    NARCIS (Netherlands)

    Sotomayor-Beltran, C.; Sobey, C.; Hessels, J.W.T.; Bruyn, de G.; Noutsos, A.; Alexov, A.; Anderson, J.; Asgekar, A.; Avruch, I.M.; Beck, R.; Bell, M.E.; Bell, M.R.; Bentum, M.J.; Bernardi, G.; Best, P.; Birzan, L.; Bonafede, A.; Breitling, F.; Broderick, J.; Brouw, W.N.; Brüggen, M.; Ciardi, B.; Gasperin, de F.; Dettmar, R.-J.; Duin, van A.; Duscha, S.; Eislöffel, J.; Falcke, H.; Fallows, R.A.; Fender, R.; Ferrari, C.; Frieswijk, W.; Garrett, M.A.; Griessmeier, J.; Grit, T.; Gunst, A.W.; Hassall, T.E.; Heald, G.; Hoeft, M.; Horneffer, A.; Iacobelli, M.; Juette, E.; Karastergiou, A.; Keane, E.; Kohler, J; Kramer, M.; Kondratiev, V.I.; Koopmans, L.V.E.; Kuniyoshi, M.; Kuper, G.; Leeuwen, van J.; Maat, P.; Macario, G.; Markoff, S.; McKean, J.P.; Mulcahy, D.D.; Munk, H.; Orrú, E.; Paas, H.; Pandey-Pommier, M.; Pilia, M.; Pizzo, R.; Polatidis, A.G.; Reich, W.; Röttgering, H.; Serylak, M.; Sluman, J.; Stappers, B.W.; Tagger, M.; Tang, Y.; Tasse, C.; Veen, ter S.; Vermeulen, R.; Weeren, van R.J.; Wijers, R.A.M.J.; Wijnholds, S.J.; Wise, M.W.; Wucknitz, O.; Yatawatta, S.; Zarka, P.

    2013-01-01

    Faraday rotation measurements using the current and next generation of low-frequency radio telescopes will provide a powerful probe of astronomical magnetic fields. However, achieving the full potential of these measurements requires accurate removal of the time-variable ionospheric Faraday rotation

  19. Calibrating high-precision Faraday rotation measurements for LOFAR and the next generation of low-frequency radio telescopes

    NARCIS (Netherlands)

    Sotomayor-Beltran, C.; et al., [Unknown; Hessels, J.W.T.; Alexov, A.; van Leeuwen, J.; Markoff, S.; Wijers, R.A.M.J.; Wise, M.W.

    2013-01-01

    Faraday rotation measurements using the current and next generation of low-frequency radio telescopes will provide a powerful probe of astronomical magnetic fields. However, achieving the full potential of these measurements requires accurate removal of the time-variable ionospheric Faraday rotation

  20. Measurement of complicated temperature-dependent polarization of multiferroic RMn2O5

    Science.gov (United States)

    Fukunaga, Mamoru; Noda, Yukio

    2011-09-01

    We have measured the temperature-dependent electric polarization P(T) of multiferroic rare-earth (R) manganese oxides RMn2O5 using both typical pyroelectric measurements and hysteresis loops with the double-wave method (DWM), and revealed the complicated behavior of the P(T). RMn2O5 single crystal samples often exhibit a tendency to macroscopically polarize without applying an external electric field. We have found that the tendency appeared in P(T) by the pyroelectric measurement can be measured by the DWM loops. The tendency to polarize is equivalent to asymmetric non-hystersis loops obtained by the DWM. We clarify the relationship between P(T) by pyroelectric measurement and that by the DWM loops, which can warrant the measured P(T).

  1. Passive remote sensing of aerosol layer height using near-UV multiangle polarization measurements

    Science.gov (United States)

    Wu, Lianghai; Hasekamp, Otto; Diedenhoven, Bastiaan; Cairns, Brian; Yorks, John E.; Chowdhary, Jacek

    2016-08-01

    We demonstrate that multiangle polarization measurements in the near-UV and blue part of the spectrum are very well suited for passive remote sensing of aerosol layer height. For this purpose we use simulated measurements with different setups (different wavelength ranges, with and without polarization, different polarimetric accuracies) as well as airborne measurements from the Research Scanning Polarimeter (RSP) obtained over the continental USA. We find good agreement of the retrieved aerosol layer height from RSP with measurements from the Cloud Physics Lidar showing a mean absolute difference of less than 1 km. Furthermore, we found that the information on aerosol layer height is provided for large part by the multiangle polarization measurements with high accuracy rather than the multiangle intensity measurements. The information on aerosol layer height is significantly decreased when the shortest RSP wavelength (410 nm) is excluded from the retrieval and is virtually absent when 550 nm is used as shortest wavelength.

  2. FPGA-based digital signal processing for the next generation radio astronomy instruments: ultra-pure sideband separation and polarization detection

    Science.gov (United States)

    Alvear, Andrés.; Finger, Ricardo; Fuentes, Roberto; Sapunar, Raúl; Geelen, Tom; Curotto, Franco; Rodríguez, Rafael; Monasterio, David; Reyes, Nicolás.; Mena, Patricio; Bronfman, Leonardo

    2016-07-01

    Field Programmable Gate Arrays (FPGAs) capacity and Analog to Digital Converters (ADCs) speed have largely increased in the last decade. Nowadays we can find one million or more logic blocks (slices) as well as several thousand arithmetic units (ALUs/DSP) available on a single FPGA chip. We can also commercially procure ADC chips reaching 10 GSPS, with 8 bits resolution or more. This unprecedented power of computing hardware has allowed the digitalization of signal processes traditionally performed by analog components. In radio astronomy, the clearest example has been the development of digital sideband separating receivers which, by replacing the IF hybrid and calibrating the system imbalances, have exhibited a sideband rejection above 40dB; this is 20 to 30dB higher than traditional analog sideband separating (2SB) receivers. In Rodriguez et al.,1 and Finger et al.,2 we have demonstrated very high digital sideband separation at 3mm and 1mm wavelengths, using laboratory setups. We here show the first implementation of such technique with a 3mm receiver integrated into a telescope, where the calibration was performed by quasi-optical injection of the test tone in front of the Cassegrain antenna. We also reported progress in digital polarization synthesis, particularly in the implementation of a calibrated Digital Ortho-Mode Transducer (DOMT) based on the Morgan et al. proof of concept.3 They showed off- line synthesis of polarization with isolation higher than 40dB. We plan to implement a digital polarimeter in a real-time FPGA-based (ROACH-2) platform, to show ultra-pure polarization isolation in a non-stop integrating spectrometer.

  3. Polar Sea Ice Monitoring Using HY-2A Scatterometer Measurements

    Directory of Open Access Journals (Sweden)

    Mingming Li

    2016-08-01

    Full Text Available A sea ice detection algorithm based on Fisher’s linear discriminant analysis is developed to segment sea ice and open water for the Ku-band scatterometer onboard the China’s Hai Yang 2A Satellite (HY-2A/SCAT. Residual classification errors are reduced through image erosion/dilation techniques and sea ice growth/retreat constraint methods. The arctic sea-ice-type classification is estimated via a time-dependent threshold derived from the annual backscatter trends based on previous HY-2A/SCAT derived sea ice extent. The extent and edge of the sea ice obtained in this study is compared with the Special Sensor Microwave Imager/Sounder (SSMIS sea ice concentration data and the Sentinel-1 SAR imagery for verification, respectively. Meanwhile, the classified sea ice type is compared with a multi-sensor sea ice type product based on data from the Advanced Scatterometer (ASCAT and SSMIS. Results show that HY-2A/SCAT is powerful in providing sea ice extent and type information, while differences in the sensitivities of active/passive products are found. In addition, HY-2A/SCAT derived sea ice products are also proved to be valuable complements for existing polar sea ice data products.

  4. Experimental measurement of the self-healing of the spatially inhomogeneous states of polarization of radially and azimuthally polarized vector Bessel beams

    CERN Document Server

    Milione, Giovanni; Nguyen, Thien An; Chakraborty, Ougni; Karimi, Ebrahim; Forbes, Andrew; Alfano, Robert R

    2014-01-01

    We experimentally measured the self-healing of the spatially inhomogeneous states of polarization of radial and azimuthal polarized vector Bessel beams. Radial and azimuthal polarized vector Bessel beams were generated via a digital version of Durnin's method, using a spatial light modulator in concert with a liquid crystal $q$-plate. As a proof of principle, their intensities and spatially inhomogeneous states of polarization were measured using Stokes polarimetry as they propagated through two disparate obstructions. It was found, similar to their intensities, the spatially inhomogeneous states of polarization of a radial and azimuthal polarized vector Bessel beams self-heal. Similar to scalar Bessel beams, the self-healing of vector Bessel beams can be understood via geometric optics, i.e., the interference of the unobstructed conical rays in the shadow region of the obstruction. The self-healing of vector Bessel beams may have applications in, for example, optical trapping.

  5. Electric field and radio frequency measurements for rocket engine health monitoring applications

    Science.gov (United States)

    Valenti, Elizabeth L.

    1992-10-01

    Electric-field (EF) and radio-frequency (RF) emissions generated in the exhaust plumes of the diagnostic testbed facility thruster (DTFT) and the SSME are examined briefly for potential applications to plume diagnostics and engine health monitoring. Hypothetically, anomalous engine conditions could produce measurable changes in any characteristic EF and RF spectral signatures identifiable with a 'healthly' plumes. Tests to determine the presence of EF and RF emissions in the DTFT and SSME exhaust plumes were conducted. EF and RF emissions were detected using state-of-the-art sensors. Analysis of limited data sets show some apparent consistencies in spectral signatures. Significant emissions increases were detected during controlled tests using dopants injected into the DTFT.

  6. A Database for Storing the Results of Material Radio-purity Measurements

    CERN Document Server

    Loach, J C; Cox, G A; Li, Z; Nguyen, K D; Poon, A W P

    2016-01-01

    Searches for rare nuclear processes, such as neutrinoless double beta-decay and the interactions of WIMP dark matter, are motivating experiments with ever-decreasing levels of radioactive backgrounds. These background reductions are achieved using various techniques, but amongst the most important is minimizing radioactive contamination in the materials from which the experiment is constructed. To this end there have been decades of advances in material sourcing, manufacture and certification, during which researchers have accumulated many thousands of measurements of material radio-purity. Some of these assays are described in publications, others are in databases, but many are still communicated informally. Until this work, there has been no standard format for encoding assay results and no effective, central location for storing them. The aim of this work is to address these long-standing problems by creating a concise and flexible material assay data format and powerful software application to manipulate ...

  7. A computationally assisted spectroscopic technique to measure secondary electron emission coefficients in radio frequency plasmas

    CERN Document Server

    Daksha, M; Schuengel, E; Korolov, I; Derzsi, A; Koepke, M; Donko, Z; Schulze, J

    2016-01-01

    A Computationally Assisted Spectroscopic Technique to measure secondary electron emission coefficients ($\\gamma$-CAST) in capacitively-coupled radio-frequency plasmas is proposed. This non-intrusive, sensitive diagnostic is based on a combination of Phase Resolved Optical Emission Spectroscopy and particle-based kinetic simulations. In such plasmas (under most conditions in electropositive gases) the spatio-temporally resolved electron-impact excitation/ionization rate features two distinct maxima adjacent to each electrode at different times within each RF period. While one maximum is the consequence of the energy gain of electrons due to sheath expansion, the second maximum is produced by secondary electrons accelerated towards the plasma bulk by the sheath electric field at the time of maximum voltage drop across the adjacent sheath. Due to these different excitation/ionization mechanisms, the ratio of the intensities of these maxima is very sensitive to the secondary electron emission coefficient $\\gamma$...

  8. The Correlation between Dispersion Measure and X-ray Column Density from Radio Pulsars

    CERN Document Server

    He, C; Kaspi, V M

    2013-01-01

    Pulsars are remarkable objects that emit across the entire electromagnetic spectrum, providing a powerful probe of the interstellar medium. In this study, we investigate the relation between dispersion measure (DM) and X-ray absorption column density NH using 68 radio pulsars detected at X-ray energies with the Chandra X-ray Observatory or XMM-Newton. We find a best-fit empirical linear relation of NH (10^20 cm^-2)= 0.30+0.13-0.09 DM (pc cm^-3), which corresponds to an average ionization of 10+4-3%, confirming the ratio of one free electron per ten neutral hydrogen atoms commonly assumed in the literature. We also compare different NH estimates and note that some NH values obtained from X-ray observations are higher than the total Galactic HI column density along the same line of sight, while the optical extinction generally gives the best NH predictions.

  9. MEASUREMENT STAND FOR STUDY PROPERTIES OF ISOLATION MATERIALS USING POLARIZATION METHOD

    Directory of Open Access Journals (Sweden)

    P. Zukowski

    2014-01-01

    Full Text Available The article presents measurement stand, which is used to measure polarization and depolarization currents, using PDC method, in wet transformer oil-impregnated cellulose isolation. Maximum resolution of measured currents reaches 10-15  A. The accuracy of thermal stabilization, in three-electrode capacitor system, comes to 0,001 °C.

  10. Calculation of smoke plume mass from passive UV satellite measurements by GOME-2 polarization measurement devices

    Science.gov (United States)

    Penning de Vries, M. J. M.; Tuinder, O. N. E.; Wagner, T.; Fromm, M.

    2012-04-01

    The Wallow wildfire of 2011 was one of the most devastating fires ever in Arizona, burning over 2,000 km2 in the states of Arizona and New Mexico. The fire originated in the Bear Wallow Wilderness area in June, 2011, and raged for more than a month. The intense heat of the fire caused the formation of a pyro-convective cloud. The resulting smoke plume, partially located above low-lying clouds, was detected by several satellite instruments, including GOME-2 on June 2. The UV Aerosol Index, indicative of aerosol absorption, reached a maximum of 12 on that day, pointing to an elevated plume with moderately absorbing aerosols. We have performed extensive model calculations assuming different aerosol optical properties to determine the total aerosol optical depth of the plume. The plume altitude, needed to constrain the aerosol optical depth, was obtained from independent satellite measurements. The model results were compared with UV Aerosol Index and UV reflectances measured by the GOME-2 polarization measurement devices, which have a spatial resolution of roughly 10x40 km2. Although neither the exact aerosol optical properties nor optical depth can be obtained with this method, the range in aerosol optical depth values that we calculate, combined with the assumed specific extinction mass factor of 5 m2/kg lead us to a rough estimate of the smoke plume mass that cannot, at present, be assessed in another way.

  11. Extracting Host Galaxy Dispersion Measure and Constraining Cosmological Parameters using Fast Radio Burst Data

    Science.gov (United States)

    Yang, Yuan-Pei; Zhang, Bing

    2016-10-01

    The excessive dispersion measures (DMs) and high Galactic latitudes of fast radio bursts (FRBs) hint toward a cosmological origin of these mysterious transients. Methods of using measured DM and redshift z to study cosmology have been proposed, but one needs to assume a certain amount of DM contribution from the host galaxy ({{DM}}{HG}) in order to apply those methods. We introduce a slope parameter β (z)\\equiv d{ln} /d{ln}z (where {{DM}}{{E}} is the observed DM subtracting the Galactic contribution), which can be directly measured when a sample of FRBs have z measured. We show that can be roughly inferred from β and the mean values, \\overline{ } and \\bar{z}, of the sample. Through Monte Carlo simulations, we show that the mean value of local host galaxy DM, , along with other cosmological parameters (mass density {{{Ω }}}m in the ΛCDM model, and the IGM portion of the baryon energy density {{{Ω }}}b{f}{IGM}), can be independently measured through Markov Chain Monte Carlo fitting to the data.

  12. Beam emittance measurements and simulations of injector line for radio frequency quadrupole

    Science.gov (United States)

    Mathew, Jose V.; Rao, S. V. L. S.; Pande, Rajni; Singh, P.

    2015-07-01

    A 400 keV deuteron (D+) radio frequency quadrupole (RFQ) accelerator has been designed, built, and commissioned at the Bhabha Atomic Research Centre, India. A beam line has been developed for injecting deuterons into the 400 keV RFQ. This comprises of a RF plasma ion source and a low energy beam transport (LEBT) system, consisting of two solenoid magnets and two steerer magnets. The ion source is characterized in terms of transverse beam emittance. A slit-wire scanner based emittance measurement setup has been developed for the transverse emittance measurements of H+ and D+ beams. The measured emittance values are found to be well within the acceptance value for the RFQ. These measured emittance parameters are used to optimize the solenoid fields in LEBT to match the beam from the ion source to RFQ. TRACEWIN simulation code is used for the beam transport simulations. The simulations show 99% transmission of D+ beam through the RFQ, while 95% transmission has been measured experimentally.

  13. Extracting host galaxy dispersion measure and constraining cosmological parameters using fast radio burst data

    CERN Document Server

    Yang, Yuan-Pei

    2016-01-01

    The excessive dispersion measures (DMs) and high Galactic latitudes of fast radio bursts (FRBs) hint toward a cosmological origin of these mysterious transients. Methods of using measured DM and redshift $z$ to study cosmology have been proposed, but one needs to assume a certain amount of DM contribution from the host galaxy (DM$_{\\rm HG}$) in order to apply those methods. We introduce a slope parameter $\\beta(z) \\equiv d \\ln \\left / d \\ln z$ (where DM$_{\\rm E}$ is the observed DM subtracting the Galactic contribution), which can be directly measured when a sample of FRBs have $z$ measured. We show that $\\left$ can be roughly inferred from $\\beta$ and the mean values, $\\overline{\\rm \\left}$ and $\\bar z$, of the sample. Through Monte Carlo simulations, we show that the mean value of local host galaxy DM, $\\left$, along with other cosmological parameters (mass density $\\Omega_m$ in the $\\Lambda$CDM model, and the IGM portion of the baryon energy density $\\Omega_b f_{\\rm IGM}$) can be independently measured thr...

  14. Radio Measurements of the Stellar Proper Motions in the Core of the Orion Nebula Cluster

    Science.gov (United States)

    Dzib, Sergio A.; Loinard, Laurent; Rodríguez, Luis F.; Gómez, Laura; Forbrich, Jan; Menten, Karl M.; Kounkel, Marina A.; Mioduszewski, Amy J.; Hartmann, Lee; Tobin, John J.; Rivera, Juana L.

    2017-01-01

    Using multi-epoch Very Large Array observations, covering a time baseline of 29.1 years, we have measured the proper motions of 88 young stars with compact radio emission in the core of the Orion Nebula Cluster (ONC) and the neighboring BN/KL region. Our work increases the number of young stars with measured proper motion at radio frequencies by a factor of 2.5 and enables us to perform a better statistical analysis of the kinematics of the region than was previously possible. Most stars (79 out of 88) have proper motions consistent with a Gaussian distribution centered on \\overline{{μ }α \\cos δ }=1.07+/- 0.09 mas yr‑1, and \\overline{{μ }δ }=-0.84+/- 0.16 mas yr‑1, with velocity dispersions of {σ }α =1.08+/- 0.07 mas yr‑1, {σ }δ =1.27+/- 0.15 mas yr‑1. We looked for organized movements of these stars but found no clear indication of radial expansion/contraction or rotation. The remaining nine stars in our sample show peculiar proper motions that differ from the mean proper motions of the ONC by more than 3σ. One of these stars, V 1326 Ori, could have been expelled from the Orion Trapezium 7000 years ago. Two could be related to the multi-stellar disintegration in the BN/KL region, in addition to the previously known sources BN, I and n. The others either have high uncertainties (so their anomalous proper motions are not firmly established) or could be foreground objects.

  15. Photoproduction of meson pairs: First measurement of the polarization observable I^s

    CERN Document Server

    Gutz, E; van Pee, H; Anisovich, A V; Bacelar, J C S; Bantes, B; Bartholomy, O; Bayadilov, D; Beck, R; Beloglazov, Yu; Castelijns, R; Crede, V; Dutz, H; Elsner, D; Ewald, R; Frommberger, F; Fuchs, M; Funke, Ch; Gregor, R; Gridnev, A; Hillert, W; Hoffmeister, Ph; Horn, I; Jaegle, I; Junkersfeld, J; Kalinowsky, H; Kammer, S; Kleber, V; Klein, Frank; Klein, Friedrich; Klempt, E; Kotulla, M; Krusche, B; Lang, M; Loehner, H; Lopatin, I; Lugert, S; Menze, D; Mertens, T; Messchendorp, J G; Metag, V; Nanova, M; Nikonov, V; Novinski, D; Novotny, R; Ostrick, M; Pant, L; Pfeiffer, M; Piontek, D; Roberts, W; Roy, A; Sarantsev, A; Schadmand, S; Schmidt, Ch; Schmieden, H; Schoch, B; Shende, S; Suele, A; Sumachev, V; Szczepanek, T; Thiel, A; Thoma, U; Trnka, D; Varma, R; Walther, D; Weinheimer, Ch; Wendel, Ch

    2009-01-01

    The polarization observable I^s, a feature exclusive to the acoplanar kinematics of multi-meson final states produced via linearly polarized photons, has been measured for the first time. Results for the reaction g p -> p pi0 eta are presented for incoming photon energies between 970 MeV and 1650 MeV along with the beam asymmetry I^c. The comparably large asymmetries demonstrate a high sensitivity of I^s to the dynamics of the reaction. Fits using Bonn-Gatchina partial wave analysis demonstrate that the new polarization observables carry significant information on the contributing partial waves.

  16. Long storage times for hyperpolarized 129Xe and precise measurement of its absolute polarization

    Energy Technology Data Exchange (ETDEWEB)

    Repetto, Maricel; Zimmer, Stefan; Karpuk, Sergei; Bluemler, Peter; Heil, Werner [Johannes Gutenberg Universitaet, Institut fuer Physik. Staudingerweg 7 55099, Mainz (Germany)

    2014-07-01

    Applications of hyperpolarized (HP) 129Xe in medical research and fundamental physics experiments increased significantly in recent years. All uses profit from high degrees of polarization (PXe) which not only needs to be generated but also preserved during transport and storage. PXe is usually determined via comparison of the NMR signals from HP Xe with the NMR signal of thermally polarized H2O or Xe. All these procedures have experimental errors which are hard to eliminate. We present a simple method for the measurement of absolute PXe which best resolution is 0.6 % together with wall storage times > 12 hs using a homebuilt, mobile Xe polarizer.

  17. Xi0 and anti-Xi0 Polarization Measurements at 800-GeV/c

    Energy Technology Data Exchange (ETDEWEB)

    Abouzaid, E.; Alavi-Harati, A.; Alexopoulos, T.; Arenton, M.; Barker, A.R.; Bellantoni, L.; Bellavance, A.; Blucher, E.; Bock, G.J.; Bright, S.; Cheu, E.; /Arizona U.

    2006-08-01

    The polarization of {Xi}{sup 0} and {bar {Xi}}{sup 0} hyperons produced by 800 GeV/c protons on a BeO target at a fixed targeting angle of 4.8 mrad is measured by the KTeV experiment at Fermilab. The result of 9.7% for {Xi}{sup 0} polarization shows no significant energy dependence when compared to a result obtained at 400 GeV/c production energy and at twice the targeting angle. The polarization of the {Xi}{sup 0} is measured for the first time and found to be consistent with zero. They also examine the dependence of polarization on production p{sub t}.

  18. Shallow water radio-magnetotelluric (RMT) measurements in urban environment: A case study from Stockholm city

    Science.gov (United States)

    Mehta, Suman; Bastani, Mehrdad; Malehmir, Alireza; Wang, Shunguo; Pedersen, Laust

    2014-05-01

    The Radio-MagnetoTelluric (RMT) method uses the electromagnetic signal from distant radio transmitters in the frequency range 15 to 250 kHz. RMT applications in near-surface studies have already been well established. Two components of electric field and three components of magnetic field are measured. These measured components are related to each other via transfer functions which contain detailed information about the variation of electrical resistivity of the subsurface. The present study is carried out in the frame of TRUST (TRansparent Underground STructure) project supported by several research and public organizations as well as industry. The study area is located close to central Stockholm in Sweden where the Swedish traffic authority has planned to construct a 21-km long motorway to bypass the city. In order to reduce the impact on natural and cultural environments, 18 km of the motorway will be located in tunnels. The main objective of this study is thus to identify potential fracture zones and faults as well as the general geological settings. The proposed path of the tunnel partly passes under the Lake Mälaren at a depth of about 60 m. Thus a challenge was posed on the applicability of RMT method in shallow water environments. Successful applications of RMT measurements using the Uppsala University's EnviroMT system on land encouraged us to modify the system to acquire data over lake water especially in urban areas. Pioneered by the Geological Survey of Sweden (SGU), RMT data were collected over the Lake Mälaren in spring 2012. The prototype acquisition system did not only turn out to be appropriate for such a challenging environment, but it was also much more efficient as compared with land surveys. Fifty two lines including 1160 stations with an average spacing of 15 m were covered in three days. Cultural noise associated with the city-related environment had to be identified and filtered out before inversion could be carried out. Reliable estimates

  19. Interference measurements on amplitude compandored single sideband (ACSB) land mobil radio

    Science.gov (United States)

    Wootton, H.

    1983-06-01

    The National Telecommunications and Information Administration (NTIA) funded the ECAC to conduct adjacent-signal interference tests on a new radio system technology that shows promise of allowing smaller channel spacing in the Government land mobile radio band (162-174 MHz). The system tested was an amplitude compandored single-sideband radio (ACSB) manufactured by Sideband Technology, Inc. This report presents the adjacent-signal interference (ASI) result which will be employed by NTIA in evaluation of the potential usage of the ACSB technology in the Government land mobile radio band.

  20. Study of Ice Crystal Orientation in Cirrus Clouds based on Satellite Polarized Radiance Measurements

    OpenAIRE

    Noel, Vincent; Chepfer, Hélène

    2004-01-01

    International audience; The goal of this paper is to retrieve information about ice particle orientation in cirrus clouds. This is achieved by comparing simulations of sunlight reflection on a cirrus cloud with measurements of polarized radiances from the spaceborne instrument Polarization and Directionality of the Earth's Reflectance (POLDER-1) on Advanced Earth Observing Satellite-1 (ADEOS-1). Results show that horizontal orientation of cr ystals can be spotted by the presence of a local ma...

  1. Quadrantids 2008 and 2009: Detection of Dust in the Atmosphere by Polarization Twilight Sky Measurements

    CERN Document Server

    Ugolnikov, Oleg S

    2009-01-01

    The paper contains the results of the polarization measurements of twilight sky background during the wintertime including the epoch of Quadrantids activity in January 2008 and 2009 in Crimea (Ukraine). Analysis of the twilight sky polarization behavior had shown the barely detectable depolarization effect at the scattering altitudes above 90 km right after the Quadrantids maximum. This effect can be related with the meteoric dust in the upper atmosphere of the Earth.

  2. Measurement of polarization observables of the associated strangeness production in proton proton interactions

    Science.gov (United States)

    Hauenstein, F.; Borodina, E.; Clement, H.; Doroshkevich, E.; Dzhygadlo, R.; Ehrhardt, K.; Eyrich, W.; Gast, W.; Gillitzer, A.; Grzonka, D.; Jowzaee, S.; Klaja, P.; Kober, L.; Kilian, K.; Krapp, M.; Mertens, M.; Moskal, P.; Ritman, J.; Roderburg, E.; Röder, M.; Schroeder, W.; Sefzick, T.; Smyrski, J.; Wintz, P.; Wüstner, P.

    2016-11-01

    The Λ polarization, the analyzing power, and the Λ spin transfer coefficient of the reaction pp → pK + Λ were measured at beam momenta of 2.70GeV/c and 2.95GeV/c corresponding to excess energies of 122MeV and 204MeV. While the analyzing power and the spin transfer coefficient do not change significantly with the excess energy, the Λ polarization varies strongly and changes its sign. As this is the first measurement of polarization observables below an excess energy of 200MeV, the change of the sign of the Λ polarization was not observed before. The high statistics of the data ( ≈ 200 k events for each momentum) enables detailed studies of the dependence of the Λ polarization and the analyzing power on the center-of-mass momentum of the particles. The results of the spin transfer coefficient are in qualitative agreement with the DISTO experiment. The Λ polarization data of 2.95GeV/c are only conform with the DISTO experiment, while both the 2.70GeV/c and 2.95GeV/c data differ strongly from all previous measurements, whether exclusive or inclusive.

  3. Measurement of polarization observables of the associated strangeness production in proton proton interactions

    CERN Document Server

    :,; Borodina, E; Clement, H; Doroshkevich, E; Dzhygadlo, R; Ehrhardt, K; Eyrich, W; Gast, W; Gillitzer, A; Grzonka, D; Jowzaee, S; Klaja, P; Kober, L; Kilian, K; Krapp, M; Mertens, M; Moskal, P; Ritman, J; Roderburg, E; Röder, M; Schroeder, W; Sefzick, T; Smyrski, J; Wintz, P; Wüstner, P

    2016-01-01

    The Lambda polarization, the analyzing power, and the Lambda spin transfer coefficient of the reaction pp -> p K+ Lambda were measured at beam momenta of 2.70 GeV/c and 2.95 GeV/c, corresponding to excess energies of 122 MeV and 204 MeV. While the analyzing power and the spin transfer coefficient do not change significantly with the excess energy, the Lambda polarization varies strongly and changes its sign. As this is the first measurement of polarization observables below an excess energy of 200 MeV, the change of the sign of the Lambda polarization was not observed before. The high statistics of the data (~200 k events for each momentum) enables detailed studies of the dependence of the Lambda polarization and the analyzing power on the center of mass momentum of the particles. The results of the spin transfer coefficient are in agreement with data from the DISTO experiment. No obvious agreement of the Lambda polarization can be found in comparison with data of high momentum measurements.

  4. Measuring the drinking behaviour of individual pigs housed in group using radio frequency identification (RFID).

    Science.gov (United States)

    Maselyne, J; Adriaens, I; Huybrechts, T; De Ketelaere, B; Millet, S; Vangeyte, J; Van Nuffel, A; Saeys, W

    2016-09-01

    Changes in the drinking behaviour of pigs may indicate health, welfare or productivity problems. Automated monitoring and analysis of drinking behaviour could allow problems to be detected, thus improving farm productivity. A high frequency radio frequency identification (HF RFID) system was designed to register the drinking behaviour of individual pigs. HF RFID antennas were placed around four nipple drinkers and connected to a reader via a multiplexer. A total of 55 growing-finishing pigs were fitted with radio frequency identification (RFID) ear tags, one in each ear. RFID-based drinking visits were created from the RFID registrations using a bout criterion and a minimum and maximum duration criterion. The HF RFID system was successfully validated by comparing RFID-based visits with visual observations and flow meter measurements based on visit overlap. Sensitivity was at least 92%, specificity 93%, precision 90% and accuracy 93%. RFID-based drinking duration had a high correlation with observed drinking duration (R 2=0.88) and water usage (R 2=0.71). The number of registrations after applying the visit criteria had an even higher correlation with the same two variables (R 2=0.90 and 0.75, respectively). There was also a correlation between number of RFID visits and number of observed visits (R 2=0.84). The system provides good quality information about the drinking behaviour of individual pigs. As health or other problems affect the pigs' drinking behaviour, analysis of the RFID data could allow problems to be detected and signalled to the farmer. This information can help to improve the productivity and economics of the farm as well as the health and welfare of the pigs.

  5. Effect of Ⅲ/Ⅴ Ratio of HT-AlN Buffer Layer on Polarity Selection and Electrical Quality of GaN Films Grown by Radio Frequency Molecular Beam Epitaxy

    Institute of Scientific and Technical Information of China (English)

    ZHONG Fei; CHEN Jia-Rong; WANG Yu-Qi; QIU Kai; LI Xin-Hua; YIN Zhi-Jun; XIE Xin-Jian; WANG Yang; JI Chang-Jian; CAO Xian-Cun; HAN Qi-Feng

    2007-01-01

    @@ We investigate the effect of Al/N ratio of the high temperature (HT) AlN buffer layer on polarity selection and electrical quality of GaN films grown by radio frequency molecular beam epitaxy. The results show that low Al/N ratio results in N-polarity GaN films and intermediate Al/N ratio leads to mixed-polarity GaN films with poor electrical quality. GaN films tend to grow with Ga polarity on Al-rich AlN buffer layers. GaN films with different polarities are confirmed by in-situ reflection high-energy electron diffraction during the growth process.Wet chemical etching, together with atomic force microscopy, also proves the polarity assignments. The optimum value for room-temperature Hall mobility of the Ga-polarity GaN film is 703cm2/V.s, which is superior to the N-polarity and mixed-polarity GaN films.

  6. Frequency and Angular Resolution for Measuring, Presenting and Predicting Loudspeaker Polar Data

    DEFF Research Database (Denmark)

    Staffeldt, Henrik; Seidel, Felicity

    1996-01-01

    The spherical polar loudspeaker data available today are usually measured with such a coarse resolution that only rough estimates of the performance of sound systems can be predicted by applying these data. Complex, spherical polar data with higher angular and frequency resolutions than used today...... measurement principles and systems, in terms of specific levels of accuracy, are also discussed. The presented material consists of research the authors have done for the AES Standards Committee SC-04-03, working group on loudspeaker modeling and measurement, toward a goal set by that working group...

  7. Measurement of ultrashort-pulse cross-polarization scattering in a tandem mirror

    Energy Technology Data Exchange (ETDEWEB)

    Kogi, Yuichiro; Mase, Atsushi [Advanced Science and Technology Center for Cooperative Research, Kyushu University, Kasuga, Fukuoka (Japan); Hojo, Hitoshi; Itakura, Akiyoshi; Ichimura, Makoto; Yatsu, Kiyoshi [Plasma Research Center, Tsukuba Univ., Tsukuba, Ibaraki (Japan)

    2001-08-01

    Cross-polarization scattering (CPS) diagnostics using ultrashort pulse microwaves is applied to the GAMMA 10 tandem mirror for the measurement of internal magnetic fluctuations. The CPS process uses the mode conversion effect of electromagnetic waves by means of magnetic fluctuations in a plasma. The mode contamination of antennas and multiple reflections from the vacuum vessel make the CPS measurement difficult since they easily mask the CPS signal. By using polarizers and performing time-of-flight measurement on the ultrashort pulse, the spurious electromagnetic waves are eliminated and the identification of the CPS process is successful. (author)

  8. Measurements of Ion Drifts and Thermospheric Neutral Winds at the Jicamarca Radio Observatory

    Science.gov (United States)

    Meriwether, J. W.; Navarro, L.; Chau, J. L.; Fejer, B. G.

    2010-12-01

    Measurements of ion drifts and thermospheric neutral winds obtained simultaneously with zonal and vertical ion drift measurements of F-region plasma have been made at the Jicamarca Radio Observatory at different times during the year since August, 2009. This period is coincident with an anomalous period of extremely low solar activity. For campaigns taking place in September, 2009, March, 2010, and September, 2010, the Jicamarca 50 MHz radar operated to measure both vertical ion drifts and horizontal neutral winds from 200 to 800 km. The Jicamarca Fabry-Perot interferometer (FPI) was installed in August, 2009, and measurements have been ongoing since first light on 15 August, 2010. The FPI instrument is located in an observatory installed on a hill overlooking the Jicamarca valley and located above the cloud inversion layer, which improved the chances of observing during local summer. This instrument after an upgrade in August 2010 is able to make zonal and meridional thermospheric wind and temperature measurements with an accuracy of 5 to 10 ms-1 and 15 to 30 K. Also obtained during the measurement campaigns with the JRO radar facility were simultaneous measurements of thermospheric winds from the FPI observatory located in Arequipa, Peru, which is located 4 degrees latitude to the south of Jicamarca. The results obtained generally showed good agreement between the observed neutral winds and ion drifts. The vertical variation of the ion drifts is significant from the early evening twilight period to midnight suggesting that the transition from the E-region dynamo to the F-region dynamo takes place rather slowly as compared with more active solar flux periods.

  9. 12 GHz Radio-Holographic surface measurement of the RRI 10.4 m telescope

    CERN Document Server

    Balasubramanyam, Ramesh; Raju, Sharath B

    2009-01-01

    A modern Q-band low noise amplifier (LNA) front-end is being fitted to the 10.4 m millimeter-wave telescope at the Raman Research Institute (RRI) to support observations in the 40-50 GHz frequency range. To assess the suitability of the surface for this purpose, we measured the deviations of the primary surface from an ideal paraboloid using radio holography. We used the 11.6996 GHz beacon signal from the GSAT3 satellite, a 1.2 m reference antenna, commercial Ku-band Low Noise Block Convereters (LNBC) as the receiver front-ends and a Stanford Research Systems (SRS) lock-in amplifier as the backend. The LNBCs had independent free-running first local oscillators (LO). Yet, we recovered the correlation by using a radiatively injected common tone that served as the second local oscillator. With this setup, we mapped the surface deviations on a 64 x 64 grid and measured an rms surface deviation of ~350 um with a measurement accuracy of ~50 um.

  10. A Survey of Worldwide Spectrum Occupancy Measurement Campaigns for Cognitive Radio

    DEFF Research Database (Denmark)

    Patil, Kishor P.; Prasad, Ramjee; Skouby, Knud Erik

    2011-01-01

    Cognitive radio is the emerging technology which provide the innovative approach to improve the spectrum utilization and alleviate the spectrum scarcity. Evaluation of the spectrum occupancy is the step toward the future deployment of cognitive radio. Worldwide several spectrum occupancy measurem...... in India....

  11. Measuring the Impact on Farmers of Agricultural Radio and Television Programs in Southwest Nigeria.

    Science.gov (United States)

    Yahaya, Mohammed Kuta; Badiru, Olabode Idris

    2002-01-01

    A survey examined the effectiveness of two long-running Nigerian agricultural programs on television and radio as perceived by 198 farmers. Results indicate a positive assessment of their value for improving agricultural production. Although more listen to the radio, the television program also received high marks. (Contains 17 references.) (JOW)

  12. Optical modeling and polarization calibration for CMB measurements with ACTPol and Advanced ACTPol

    Science.gov (United States)

    Koopman, Brian; Austermann, Jason; Cho, Hsiao-Mei; Coughlin, Kevin P.; Duff, Shannon M.; Gallardo, Patricio A.; Hasselfield, Matthew; Henderson, Shawn W.; Ho, Shuay-Pwu Patty; Hubmayr, Johannes; Irwin, Kent D.; Li, Dale; McMahon, Jeff; Nati, Federico; Niemack, Michael D.; Newburgh, Laura; Page, Lyman A.; Salatino, Maria; Schillaci, Alessandro; Schmitt, Benjamin L.; Simon, Sara M.; Vavagiakis, Eve M.; Ward, Jonathan T.; Wollack, Edward J.

    2016-07-01

    The Atacama Cosmology Telescope Polarimeter (ACTPol) is a polarization sensitive upgrade to the Atacama Cosmology Telescope, located at an elevation of 5190 m on Cerro Toco in Chile. ACTPol uses transition edge sensor bolometers coupled to orthomode transducers to measure both the temperature and polarization of the Cosmic Microwave Background (CMB). Calibration of the detector angles is a critical step in producing polarization maps of the CMB. Polarization angle offsets in the detector calibration can cause leakage in polarization from E to B modes and induce a spurious signal in the EB and TB cross correlations, which eliminates our ability to measure potential cosmological sources of EB and TB signals, such as cosmic birefringence. We calibrate the ACTPol detector angles by ray tracing the designed detector angle through the entire optical chain to determine the projection of each detector angle on the sky. The distribution of calibrated detector polarization angles are consistent with a global offset angle from zero when compared to the EB-nulling offset angle, the angle required to null the EB cross-correlation power spectrum. We present the optical modeling process. The detector angles can be cross checked through observations of known polarized sources, whether this be a galactic source or a laboratory reference standard. To cross check the ACTPol detector angles, we use a thin film polarization grid placed in front of the receiver of the telescope, between the receiver and the secondary reflector. Making use of a rapidly rotating half-wave plate (HWP) mount we spin the polarizing grid at a constant speed, polarizing and rotating the incoming atmospheric signal. The resulting sinusoidal signal is used to determine the detector angles. The optical modeling calibration was shown to be consistent with a global offset angle of zero when compared to EB nulling in the first ACTPol results and will continue to be a part of our calibration implementation. The first

  13. Radiative transfer with POLARIS: I. Analysis of magnetic fields through synthetic dust continuum polarization measurements

    CERN Document Server

    Reissl, Stefan; Wolf, Sebastian

    2016-01-01

    \\textbf{Aims}: We present POLARIS (\\textbf{POLA}rized \\textbf{R}ad\\textbf{I}ation \\textbf{S}imulator), a newly developed three-dimensional Monte-Carlo radiative transfer code. POLARIS was designed to calculate dust temperature, polarization maps, and spectral energy distributions. It is optimized to handle data that results from sophisticated magneto-hydrodynamic simulations. The main purpose of the code is to prepare and analyze multi-wavelength continuum polarization measurements in the context of magnetic field studies in the interstellar medium. An exemplary application is the investigation of the role of magnetic fields in star formation processes.\\\\ \\textbf{Methods}: We combine currently discussed state-of-the-art grain alignment theories with existing dust heating and polarization algorithms. We test the POLARIS code on multiple scales in complex astrophysical systems that are associated with different stages of star formation. POLARIS uses the full spectrum of dust polarization mechanisms to trace the...

  14. Constraining axion coupling constants from measuring the Casimir interaction between polarized test bodies

    CERN Document Server

    Bezerra, V B; Mostepanenko, V M; Romero, C

    2016-01-01

    We propose an experiment for measuring the effective Casimir pressure between two parallel SiC plates with aligned nuclear spins. The prospective constraints on an axion-neutron coupling constant for both hadronic and GUT axions are calculated using the process of one-axion exchange. For this purpose, a general expression for the additional pressure arising between two polarized plates due to the exchange of one axion between their constituent fermions is derived. We demonstrate that only the polarization component perpendicular to the plates contribute to the pressure. The obtained pressure can be both repulsive and attractive depending on whether the polarizations of both plates are unidirectional or directed in opposite directions. It is shown that although the constraints on an axion-electron coupling obtained in the case of magnetized plates are not competitive, the constraints on an axion-neutron coupling found for plates with polarized nuclear spins are of the same order of magnitude of those obtained ...

  15. B-Machine Polarimeter: A Telescope to Measure the Polarization of the Cosmic Microwave Background

    CERN Document Server

    Williams, Brian D

    2013-01-01

    The B-Machine Telescope is the culmination of several years of development, construction, characterization and observation. The telescope is a departure from standard polarization chopping of correlation receivers to a half wave plate technique. Typical polarimeters use a correlation receiver to chop the polarization signal to overcome the $1/f$ noise inherent in HEMT amplifiers. B-Machine uses a room temperature half wave plate technology to chop between polarization states and measure the polarization signature of the CMB. The telescope has a demodulated $1/f$ knee of 5 mHz and an average sensitivity of 1.6 $\\mathrm{mK}\\sqrt{\\mathrm{s}}$. This document examines the construction, characterization, observation of astronomical sources, and data set analysis of B-Machine. Preliminary power spectra and sky maps with large sky coverage for the first year data set are included.

  16. B-machine polarimeter: A telescope to measure the polarization of the cosmic microwave background

    Science.gov (United States)

    Williams, Brian Dean

    The B-Machine Telescope is the culmination of several years of development, construction, characterization and observation. The telescope is a departure from standard polarization chopping of correlation receivers to a half wave plate technique. Typical polarimeters use a correlation receiver to chop the polarization signal to overcome the 1/f noise inherent in HEMT amplifiers. B-Machine uses a room temperature half wave plate technology to chop between polarization states and measure the polarization signature of the CMB. The telescope has a demodulated 1/f knee of 5 mHz and an average sensitivity of 1.6 mK s . This document examines the construction, characterization, observation of astronomical sources, and data set analysis of B-Machine. Preliminary power spectra and sky maps with large sky coverage for the first year data set are included.

  17. Polarization measurement of dielectronic recombination transitions in highly charged krypton ions

    CERN Document Server

    Shah, Chintan; Bernitt, Sven; Dobrodey, Stepan; Steinbrügge, René; Beilmann, Christian; Amaro, Pedro; Hu, Zhimin; Weber, Sebastian; Fritzsche, Stephan; Surzhykov, Andrey; López-Urrutia, José R Crespo; Tashenov, Stanislav

    2016-01-01

    We report linear polarization measurements of x rays emitted due to dielectronic recombination into highly charged krypton ions. The ions in the He-like through O-like charge states were populated in an electron beam ion trap with the electron beam energy adjusted to recombination resonances in order to produce $K\\alpha$ x rays. The x rays were detected with a newly developed Compton polarimeter using a beryllium scattering target and 12 silicon x-ray detector diodes sampling the azimuthal distribution of the scattered x rays. The extracted degrees of linear polarization of several dielectronic recombination transitions agree with results of relativistic distorted--wave calculations. We also demonstrate a high sensitivity of the polarization to the Breit interaction, which is remarkable for a medium-$Z$ element like krypton. The experimental results can be used for polarization diagnostics of hot astrophysical and laboratory fusion plasmas.

  18. Automatic DGD and GVD compensation at 640 Gb/s based on scalar radio-frequency spectrum measurement

    DEFF Research Database (Denmark)

    Paquot, Yvan; Schröder, Jochen; Palushani, Evarist;

    2013-01-01

    of separate GVD and DGD compensators using an impairment monitor based on an integrated all-optical radio-frequency (RF) spectrum analyzer. We show that low-bandwidth measurement of only a single tone in the RF spectrum is sufficient for automatic compensation for multiple degrees of freedom using...

  19. Photoelectronic vibrometer with polarized light. [for torsional vibration measurements

    Science.gov (United States)

    Kremmer, I.

    1974-01-01

    A seismic torsiometer is described which is based on the reception by a photosensitive transducer of a light flux modulated by a relative rotation of the optical axes of two polaroids. The torsional vibrations of the polaroid fixed to the shaft are transmitted to the other polaroid (which at the same time is the seismic mass of the apparatus) by means of elastic lamellas. The device can work as accelerometer, vibrometer or frequency meter, depending on the value of the ratio between the proper oscillation frequency of the seismic system and the measured vibration frequency.

  20. Broadband Radio Polarimetry and Faraday Rotation of 563 Extragalactic Radio Sources

    CERN Document Server

    Anderson, C S; Feain, I J; Franzen, T M O

    2015-01-01

    We present a broadband spectropolarimetric survey of 563 discrete, mostly unresolved radio sources between 1.3 \\& 2.0 GHz using data taken with the Australia Telescope Compact Array (ATCA). We have used rotation measure synthesis to identify Faraday complex polarized sources --- i.e. objects whose frequency-dependent polarization behaviour indicates the presence of material possessing complicated magnetoionic structure along the line of sight (LOS). For sources classified as Faraday complex, we have analyzed a number of their radio and multiwavelength properties to determine whether they differ from Faraday simple polarized sources (i.e. sources for which LOS magnetoionic structures are comparatively simple) in these properties. We use this information to constrain the physical nature of the magnetoionic structures responsible for generating the observed complexity. We detect Faraday complexity in 12\\% of polarized sources at $\\sim1'$ resolution, but demonstrate that underlying signal-to-noise limitations...

  1. Measurement of the W boson polarization in top quark decays with the ATLAS detector

    CERN Document Server

    Aad, Georges; Abdallah, Jalal; Abdel Khalek, Samah; Abdelalim, Ahmed Ali; Abdinov, Ovsat; Abi, Babak; Abolins, Maris; AbouZeid, Ossama; Abramowicz, Halina; Abreu, Henso; Acerbi, Emilio; Acharya, Bobby Samir; Adamczyk, Leszek; Adams, David; Addy, Tetteh; Adelman, Jahred; Adomeit, Stefanie; Adragna, Paolo; Adye, Tim; Aefsky, Scott; Aguilar-Saavedra, Juan Antonio; Agustoni, Marco; Aharrouche, Mohamed; Ahlen, Steven; Ahles, Florian; Ahmad, Ashfaq; Ahsan, Mahsana; Aielli, Giulio; Akdogan, Taylan; Åkesson, Torsten Paul Ake; Akimoto, Ginga; Akimov, Andrei; Akiyama, Kunihiro; Alam, Mohammad; Alam, Muhammad Aftab; Albert, Justin; Albrand, Solveig; Aleksa, Martin; Aleksandrov, Igor; Alessandria, Franco; Alexa, Calin; Alexander, Gideon; Alexandre, Gauthier; Alexopoulos, Theodoros; Alhroob, Muhammad; Aliev, Malik; Alimonti, Gianluca; Alison, John; Allbrooke, Benedict; Allport, Phillip; Allwood-Spiers, Sarah; Almond, John; Aloisio, Alberto; Alon, Raz; Alonso, Alejandro; Alvarez Gonzalez, Barbara; Alviggi, Mariagrazia; Amako, Katsuya; Amelung, Christoph; Ammosov, Vladimir; Amorim, Antonio; Amram, Nir; Anastopoulos, Christos; Ancu, Lucian Stefan; Andari, Nansi; Andeen, Timothy; Anders, Christoph Falk; Anders, Gabriel; Anderson, Kelby; Andreazza, Attilio; Andrei, George Victor; Anduaga, Xabier; Anger, Philipp; Angerami, Aaron; Anghinolfi, Francis; Anisenkov, Alexey; Anjos, Nuno; Annovi, Alberto; Antonaki, Ariadni; Antonelli, Mario; Antonov, Alexey; Antos, Jaroslav; Anulli, Fabio; Aoun, Sahar; Aperio Bella, Ludovica; Apolle, Rudi; Arabidze, Giorgi; Aracena, Ignacio; Arai, Yasuo; Arce, Ayana; Arfaoui, Samir; Arguin, Jean-Francois; Arik, Engin; Arik, Metin; Armbruster, Aaron James; Arnaez, Olivier; Arnal, Vanessa; Arnault, Christian; Artamonov, Andrei; Artoni, Giacomo; Arutinov, David; Asai, Shoji; Asfandiyarov, Ruslan; Ask, Stefan; Åsman, Barbro; Asquith, Lily; Assamagan, Ketevi; Astbury, Alan; Aubert, Bernard; Auge, Etienne; Augsten, Kamil; Aurousseau, Mathieu; Avolio, Giuseppe; Avramidou, Rachel Maria; Axen, David; Azuelos, Georges; Azuma, Yuya; Baak, Max; Baccaglioni, Giuseppe; Bacci, Cesare; Bach, Andre; Bachacou, Henri; Bachas, Konstantinos; Backes, Moritz; Backhaus, Malte; Badescu, Elisabeta; Bagnaia, Paolo; Bahinipati, Seema; Bai, Yu; Bailey, David; Bain, Travis; Baines, John; Baker, Oliver Keith; Baker, Mark; Baker, Sarah; Banas, Elzbieta; Banerjee, Piyali; Banerjee, Swagato; Banfi, Danilo; Bangert, Andrea Michelle; Bansal, Vikas; Bansil, Hardeep Singh; Barak, Liron; Baranov, Sergei; Barbaro Galtieri, Angela; Barber, Tom; Barberio, Elisabetta Luigia; Barberis, Dario; Barbero, Marlon; Bardin, Dmitri; Barillari, Teresa; Barisonzi, Marcello; Barklow, Timothy; Barlow, Nick; Barnett, Bruce; Barnett, Michael; Baroncelli, Antonio; Barone, Gaetano; Barr, Alan; Barreiro, Fernando; Barreiro Guimarães da Costa, João; Barrillon, Pierre; Bartoldus, Rainer; Barton, Adam Edward; Bartsch, Valeria; Bates, Richard; Batkova, Lucia; Batley, Richard; Battaglia, Andreas; Battistin, Michele; Bauer, Florian; Bawa, Harinder Singh; Beale, Steven; Beau, Tristan; Beauchemin, Pierre-Hugues; Beccherle, Roberto; Bechtle, Philip; Beck, Hans Peter; Becker, Anne Kathrin; Becker, Sebastian; Beckingham, Matthew; Becks, Karl-Heinz; Beddall, Andrew; Beddall, Ayda; Bedikian, Sourpouhi; Bednyakov, Vadim; Bee, Christopher; Begel, Michael; Behar Harpaz, Silvia; Beimforde, Michael; Belanger-Champagne, Camille; Bell, Paul; Bell, William; Bella, Gideon; Bellagamba, Lorenzo; Bellina, Francesco; Bellomo, Massimiliano; Belloni, Alberto; Beloborodova, Olga; Belotskiy, Konstantin; Beltramello, Olga; Benary, Odette; Benchekroun, Driss; Bendtz, Katarina; Benekos, Nektarios; Benhammou, Yan; Benhar Noccioli, Eleonora; Benitez Garcia, Jorge-Armando; Benjamin, Douglas; Benoit, Mathieu; Bensinger, James; Benslama, Kamal; Bentvelsen, Stan; Berge, David; Bergeaas Kuutmann, Elin; Berger, Nicolas; Berghaus, Frank; Berglund, Elina; Beringer, Jürg; Bernat, Pauline; Bernhard, Ralf; Bernius, Catrin; Berry, Tracey; Bertella, Claudia; Bertin, Antonio; Bertolucci, Federico; Besana, Maria Ilaria; Besjes, Geert-Jan; Besson, Nathalie; Bethke, Siegfried; Bhimji, Wahid; Bianchi, Riccardo-Maria; Bianco, Michele; Biebel, Otmar; Bieniek, Stephen Paul; Bierwagen, Katharina; Biesiada, Jed; Biglietti, Michela; Bilokon, Halina; Bindi, Marcello; Binet, Sebastien; Bingul, Ahmet; Bini, Cesare; Biscarat, Catherine; Bitenc, Urban; Black, Kevin; Blair, Robert; Blanchard, Jean-Baptiste; Blanchot, Georges; Blazek, Tomas; Blocker, Craig; Blocki, Jacek; Blondel, Alain; Blum, Walter; Blumenschein, Ulrike

    2012-01-01

    This paper presents measurements of the polarization of W bosons in top quark decays, derived from ttbar events with missing transverse momentum, one charged lepton and at least four jets, or two charged leptons and at least two jets. Data from pp collisions at a centre-of-mass energy of 7 TeV were collected with the ATLAS experiment at the LHC and correspond to an integrated luminosity of 1.04 fb^-1. The measured fractions of longitudinally, left- and right-handed polarization are F_0=0.67+/-0.07, F_L=0.32+/-0.04 and F_R=0.01+/-0.05, in agreement with the Standard Model predictions. As the polarization of the W bosons in top quark decays is sensitive to the Wtb vertex Lorentz structure and couplings, the measurements were used to set limits on anomalous contributions to the Wtb couplings.

  2. Questions and prospects in quarkonium polarization measurements from proton-proton to nucleus-nucleus collisions

    CERN Document Server

    Faccioli, Pietro

    2012-01-01

    Polarization measurements are the best instrument to understand how quark and antiquark combine into the different quarkonium states, but no model has so far succeeded in explaining the measured J/psi and Upsilon polarizations. On the other hand, the experimental data in proton-antiproton and proton-nucleus collisions are inconsistent, incomplete and ambiguous. New analyses will have to properly address often underestimated issues: the existence of azimuthal anisotropies, the dependence on the reference frame, the influence of the experimental acceptance on the comparison with other measurements and with theory. Additionally, a recently developed frame-invariant formalism will provide an alternative and often more immediate physical viewpoint and, at the same time, will help probing systematic effects due to experimental biases. The role of feed-down decays from heavier states, a crucial missing piece in the current experimental knowledge, will have to be investigated. Ultimately, quarkonium polarization meas...

  3. Measurement of the $t\\bar{t}$ spin correlations and top quark polarization in dileptonic channel

    CERN Document Server

    Khatiwada, Ajeeta

    2017-01-01

    The degree of top polarization and strength of $t\\bar{t}$ correlation are dependent on production dynamics, decay mechanism, and choice of the observables. At the LHC, measurement of the top polarization and spin correlations in $t\\bar{t}$ production is possible through various observables related to the angular distribution of decay leptons. A measurement of differential distribution provides a precision test of the standard model of particle physics and probes for deviations, which could be a sign of new physics. In particular, the phase space for the super-symmetric partner of the top quark can be constrained. Results from the Compact Muon Solenoid (CMS) collaboration for top quark polarization and spin correlation in the dileptonic channel are reviewed briefly in this proceeding. The measurements are obtained using 19.5 fb$^{-1}$ of data collected in pp collisions at the center-of-mass energy of 8 TeV.

  4. Analytic Calculation of Radio Emission from Extensive Air Showers subjected to Atmospheric Electric Fields

    CERN Document Server

    Scholten, Olaf; de Vries, Krijn D; van Sloten, Lucas

    2016-01-01

    We have developed a code that semi-analytically calculates the radio footprint (intensity and polarization) of an extensive air shower subject to atmospheric electric fields. This can be used to reconstruct the height dependence of atmospheric electric field from the measured radio footprint. The various parameterizations of the spatial extent of the induced currents are based on the results of Monte-Carlo shower simulations. The calculated radio footprints agree well with microscopic CoREAS simulations.

  5. Measurement of the radius of Mercury by radio occultation during the MESSENGER flybys

    Science.gov (United States)

    Perry, Mark E.; Kahan, Daniel S.; Barnouin, Olivier S.; Ernst, Carolyn M.; Solomon, Sean C.; Zuber, Maria T.; Smith, David E.; Phillips, Roger J.; Srinivasan, Dipak K.; Oberst, Jürgen; Asmar, Sami W.

    2011-12-01

    The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft completed three flybys of Mercury in 2008-2009. During the first and third of those flybys, MESSENGER passed behind the planet from the perspective of Earth, occulting the radio-frequency (RF) transmissions. The occultation start and end times, recovered with 0.1 s accuracy or better by fitting edge-diffraction patterns to the RF power history, are used to estimate Mercury's radius at the tangent point of the RF path. To relate the measured radius to the planet shape, we evaluate local topography using images to identify the high-elevation feature that defines the RF path or using altimeter data to quantify surface roughness. Radius measurements are accurate to 150 m, and uncertainty in the average radius of the surrounding terrain, after adjustments are made from the local high at the tangent point of the RF path, is 350 m. The results are consistent with Mercury's equatorial shape as inferred from observations by the Mercury Laser Altimeter and ground-based radar. The three independent estimates of radius from occultation events collectively yield a mean radius for Mercury of 2439.2±0.5 km.

  6. Radio-echo sounding at Dome C, East Antarctica: A comparison of measured and modeled data

    Science.gov (United States)

    Winter, Anna; Eisen, Olaf; Steinhage, Daniel; Zirizzotti, Achille; Urbini, Stefano; Cavitte, Marie; Blankenship, Donald D.; Wolff, Eric

    2016-04-01

    The internal layering architecture of ice sheets, detected with radio-echo sounding (RES), contains clues to past ice-flow dynamics and mass balance. A common way of relating the recorded travel time of RES reflections to depth is by integrating a wave-speed distribution. This results in an increasing absolute error with depth. We present a synchronization of RES-internal layers of different radar systems (Alfred Wegener Institute, Center for Remote Sensing of Ice Sheets, Istituto Nazionale di Geofisica e Vulcanologia, British Antarctic Survey and University of Texas Institute for Geophysics) with ice-core records from the Antarctic deep drill site Dome C. Synthetic radar traces are obtained from measurements of ice-core density and conductivity with a 1D model of Maxwell's equations. The reflection peaks of the different radar systems' measurements are shifted by a wiggle-matching algorithm, so they match the synthetic trace. In this way, we matched pronounced internal reflections in the RES data to conductivity peaks with considerably smaller depth uncertainties, and assigned them with the ice-core age. We examine the differences in shifts and resolution of the different RES data to address the question of their comparability and combined analysis for an extensive age-depth distribution.

  7. Improved measurement of the spectral index of the diffuse radio background between 90 and 190 MHz

    Science.gov (United States)

    Mozdzen, T. J.; Bowman, J. D.; Monsalve, R. A.; Rogers, A. E. E.

    2017-02-01

    We report absolutely calibrated measurements of diffuse radio emission between 90 and 190 MHz from the Experiment to Detect the Global EoR Signature (EDGES). EDGES employs a wide beam zenith-pointing dipole antenna centred on a declination of -26.7°. We measure the sky brightness temperature as a function of frequency averaged over the EDGES beam from 211 nights of data acquired from 2015 July to 2016 March. We derive the spectral index, β, as a function of local sidereal time (LST) and find -2.60 > β > -2.62 ± 0.02 between 0 and 12 h LST. When the Galactic Centre is in the sky, the spectral index flattens, reaching β = -2.50 ± 0.02 at 17.7 h. The EDGES instrument is shown to be very stable throughout the observations with night-to-night reproducibility of σβ GSM) of de Oliveira-Costa et al. and with fits between the Guzmán et al. 45 MHz and Haslam et al. 408 MHz maps. We find good agreement at the transit of the Galactic Centre. Away from transit, the GSM tends to overpredict (GSM less negative) by 0.05 < Δβ = βGSM - βEDGES < 0.12, while the 45-408 MHz fits tend to overpredict by Δβ < 0.05.

  8. Improved Measurement of the Spectral Index of the Diffuse Radio Background Between 90 and 190 MHz

    CERN Document Server

    Mozdzen, Thomas J; Monsalve, Raul A; Rogers, Alan E E

    2016-01-01

    We report absolutely calibrated measurements of diffuse radio emission between 90 and 190 MHz from the Experiment to Detect the Global EoR Signature (EDGES). EDGES employs a wide beam zenith-pointing dipole antenna centred on a declination of -26.7$^\\circ$. We measure the sky brightness temperature as a function of frequency averaged over the EDGES beam from 211 nights of data acquired from July 2015 to March 2016. We derive the spectral index, $\\beta$, as a function of local sidereal time (LST) and find -2.60 > $\\beta$ > -2.62 $\\pm$0.02 between 0 and 12 h LST. When the Galactic Centre is in the sky, the spectral index flattens, reaching $\\beta$ = -2.50 $\\pm$0.02 at 17.7 h. The EDGES instrument is shown to be very stable throughout the observations with night-to-night reproducibility of $\\sigma_{\\beta}$ < 0.003. Including systematic uncertainty, the overall uncertainty of $\\beta$ is 0.02 across all LST bins. These results improve on the earlier findings of Rogers & Bowman (2008) by reducing the spectra...

  9. Measurements of radio propagation in rock salt for the detection of high-energy neutrinos

    CERN Document Server

    Connolly, Amy; Miki, Christian; Nichol, Ryan; Saltzberg, David

    2008-01-01

    We present measurements of the transmission of radio/microwave pulses through salt in the Cote Blanche salt mine operated by the North American Salt Company in St. Mary Parish, Louisiana. These results are from data taken in the southwestern region of the 1500 ft. (457 m) deep level of the mine on our third and most recent visit to the mine. We transmitted and received a fast, high-power, broadband pulse from within three vertical boreholes that were drilled to depths of 100 ft. (30 m) and 200 ft. below the 1500 ft. level using three different pairs of dipole antennas whose bandwidths span 125 to 900 MHz. By measuring the relative strength of the received pulses between boreholes with separations of 50 m and 169 m, we deduce the attenuation of the signal attributed to the salt medium. We fit the frequency dependence of the attenuation to a power law and find the best fit field attenuation lengths to be 93 \\pm 7 m at 150 MHz, 63 \\pm 3 m at 300 MHz, and 36 \\pm 2 m at 800 MHz. This is the most precise measuremen...

  10. Calibrating High-Precision Faraday Rotation Measurements for LOFAR and the Next Generation of Low-Frequency Radio Telescopes

    CERN Document Server

    Sotomayor-Beltran, C; Hessels, J W T; de Bruyn, G; Noutsos, A; Alexov, A; Anderson, J; Asgekar, A; Avruch, I M; Beck, R; Bell, M E; Bell, M R; Bentum, M J; Bernardi, G; Best, P; Birzan, L; Bonafede, A; Breitling, F; Broderick, J; Brouw, W N; Brueggen, M; Ciardi, B; de Gasperin, F; Dettmar, R -J; van Duin, A; Duscha, S; Eisloeffel, J; Falcke, H; Fallows, R A; Fender, R; Ferrari, C; Frieswijk, W; Garrett, M A; Griessmeier, J; Grit, T; Gunst, A W; Hassall, T E; Heald, G; Hoeft, M; Horneffer, A; Iacobelli, M; Juette, E; Karastergiou, A; Keane, E; Kohler, J; Kramer, M; Kondratiev, V I; Koopmans, L V E; Kuniyoshi, M; Kuper, G; van Leeuwen, J; Maat, P; Macario, G; Markoff, S; McKean, J P; Mulcahy, D D; Munk, H; Orru, E; Paas, H; Pandey-Pommier, M; Pilia, M; Pizzo, R; Polatidis, A G; Reich, W; Roettgering, H; Serylak, M; Sluman, J; Stappers, B W; Tagger, M; Tang, Y; Tasse, C; ter Veen, S; Vermeulen, R; van Weeren, R J; Wijers, R A M J; Wijnholds, S J; Wise, M W; Wucknitz, O; Yatawatta, S; Zarka, P; 10.1051/0004-6361/201220728

    2013-01-01

    Faraday rotation measurements using the current and next generation of low-frequency radio telescopes will provide a powerful probe of astronomical magnetic fields. However, achieving the full potential of these measurements requires accurate removal of the time-variable ionospheric Faraday rotation contribution. We present ionFR, a code that calculates the amount of ionospheric Faraday rotation for a specific epoch, geographic location, and line-of-sight. ionFR uses a number of publicly available, GPS-derived total electron content maps and the most recent release of the International Geomagnetic Reference Field. We describe applications of this code for the calibration of radio polarimetric observations, and demonstrate the high accuracy of its modeled ionospheric Faraday rotations using LOFAR pulsar observations. These show that we can accurately determine some of the highest-precision pulsar rotation measures ever achieved. Precision rotation measures can be used to monitor rotation measure variations - e...

  11. Retrieval of aerosol microphysical and optical properties above liquid clouds from POLDER/PARASOL polarization measurements

    Directory of Open Access Journals (Sweden)

    F. Waquet

    2013-04-01

    Full Text Available Most of the current aerosol retrievals from passive sensors are restricted to cloud-free scenes, which strongly reduces our ability to monitor the aerosol properties at a global scale and to estimate their radiative forcing. The presence of aerosol above clouds (AAC affects the polarized light reflected by the cloud layer, as shown by the spaceborne measurements provided by the POlarization and Directionality of Earth Reflectances (POLDER instrument on the PARASOL satellite. In a previous work, a first retrieval method was developed for AAC scenes and evaluated for biomass-burning aerosols transported over stratocumulus clouds. The method was restricted to the use of observations acquired at forward scattering angles (90–120° where polarized measurements are highly sensitive to fine-mode particle scattering. Non-spherical particles in the coarse mode, such as mineral dust particles, do not much polarize light and cannot be handled with this method. In this paper, we present new developments that allow retrieving also the properties of mineral dust particles above clouds. These particles do not much polarize light but strongly reduce the polarized cloud bow generated by the liquid cloud layer beneath and observed for scattering angles around 140°. The spectral attenuation can be used to qualitatively identify the nature of the particles (i.e. accumulation mode versus coarse mode, i.e. mineral dust particles versus biomass-burning aerosols, whereas the magnitude of the attenuation is related to the optical thickness of the aerosol layer. We also use the polarized measurements acquired in the cloud bow to improve the retrieval of both the biomass-burning aerosol properties and the cloud microphysical properties. We provide accurate polarized radiance calculations for AAC scenes and evaluate the contribution of the POLDER polarization measurements for the simultaneous retrieval of the aerosol and cloud properties. We investigate various scenes

  12. Radar measurement of ionospheric scintillation in the polar region

    Science.gov (United States)

    Knepp, Dennis L.

    2015-10-01

    This paper considers several estimators that use radar data to measure the S4 scintillation index that characterizes the severity of amplitude scintillation that may occur during RF propagation through ionospheric irregularities. S4 is defined to be the standard deviation of the fluctuations in received power normalized by division by the mean power. Estimates of S4 are based on radar returns obtained during track of targets which may themselves have intrinsic radar cross-section fluctuations. Key to this work is the consideration of thresholding, which is used in many radars to remove (from further processing) signals whose SNR is considered too low. We consider several estimators here. The "direct" estimator attempts to estimate S4 through the direct calculation of the mean and standard deviation of the SNR from a number of radar returns. The maximum likelihood (ML) estimator uses multiple hypothesis testing and the assumption of Nakagami-m statistics to estimate the scintillation index that best fits the radar returns from some number of pulses. The ML estimator has perfect knowledge of the number of radar returns that are below the threshold. The direct estimator is accurate for the case where there is no threshold and there are many returns or samples from which to estimate S4. However, the direct estimator is flawed (especially for strong scintillation) if deep fades that fall below the radar threshold are ignored. The modified ML estimator here is based on the ML technique but is useful if the count of missed returns is unavailable. We apply the modified ML estimator to several years of radar tracks of large calibration satellites to obtain the statistics of UHF scintillation as viewed from the early warning radar at Thule, Greenland. One-way S4 was measured from 5000 low Earth orbit tracks during the 3 year period after solar maximum in May 2000. The data are analyzed to quantify the exceedance or the level of scintillation experienced at various

  13. Prospects for Measuring $\\Delta$G from Jets at HERA with Polarized Protons and Electrons

    CERN Document Server

    Rädel, G; Feltesse, Joel; Kunne, Fabienne; Maul, M; Mirkes, E; Schäfer, A; Wu, C Y

    1996-01-01

    The measurement of the polarized gluon distribution function Delta G(x) from photon-gluon fusion processes in electron-proton deep inelastic scattering producing two jets has been investigated. The study is based on the MEPJET and PEPSI simulation programs. The size of the expected spin asymmetry and corresponding statistical uncertainties for a possible measurement with polarized beams of electrons and protons at HERA have been estimated. The results show that the asymmetry can reach a few percent, and is not washed out by hadronization and higher order processes.

  14. Single-shot measurement of free-electron laser polarization at SDUV-FEL

    CERN Document Server

    Feng, Lie; Zhang, Tong; Feng, Chao; Chen, Jianhui; Wang, Xingtao; Lan, Taihe; Shen, Lei; Zhang, Wenyan; Yao, Haifeng; Liu, Xiaoqing; Liu, Bo; Wang, Dong

    2014-01-01

    In this paper, a division-of-amplitude photopolarimeter (DOAP) for measuring the polarization state of free-electron laser (FEL) pulse is described. The incident FEL beam is divided into four separate beams, and four Stokes parameters can be measured in a single-shot. In the crossed-planar undulators experiment at Shanghai deep ultraviolet FEL test facility, this DOAP instrument constructed in house responses accurately and timely while the polarization-state of fully coherent FEL pulses are switched, which is helpful for confirming the crossed-planar undulators technique for short-wavelength FELs.

  15. Prospects for measuring {Delta}G from jets at HERA with polarized protons and electrons

    Energy Technology Data Exchange (ETDEWEB)

    Roeck, A. de [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Feltesse, J. [CEA Centre d`Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Dept. d`Astrophysique, de Physique des Particules, de Physique Nucleaire et de l`Instrumentation Associee (DAPNIA); Kunne, F. [CEA Centre d`Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Dept. d`Astrophysique, de Physique des Particules, de Physique Nucleaire et de l`Instrumentation Associee (DAPNIA); Maul, M. [Frankfurt Univ. (Germany). Inst. fuer Theoretische Physik; Schaefer, A. [Frankfurt Univ. (Germany). Inst. fuer Theoretische Physik; Wu, C.Y. [Frankfurt Univ. (Germany). Inst. fuer Theoretische Physik; Mirkes, E. [Karlsruhe Univ. (T.H.) (Germany). Inst. fuer Theoretische Teilchenphysik; Raedel, G. [European Organization for Nuclear Research, Geneva (Switzerland). Div. Particle Physics Experiments

    1996-09-01

    The measurement of the polarized gluon distribution function {Delta}G(x) from photon-gluon fusion processes in electron-proton deep inelastic scattering producing two jets has been investigated. The study is based on the MEPJET and PEPSI simulation programs. The size of the expected spin asymmetry and corresponding statistical uncertainties for a possible measurement with polarized beams of electrons and protons at HERA have been estimated. The results show that the asymmetry can reach a few percent, and is not washed out by hadronization and higher order processes. (orig.)

  16. Radio Band Observations of Blazar Variability

    Indian Academy of Sciences (India)

    Margo F. Aller; Hugh D. Aller; Philip A. Hughes

    2011-03-01

    The properties of blazar variability in the radio band are studied using the unique combination of temporal resolution from single dish monitoring and spatial resolution from VLBA imaging. Such measurements now available in all four Stokes parameters, together with theoretical simulations, identify the origin of radio band variability and probe the characteristics of the radio jet where the broadband blazar emission originates. Outbursts in total flux density and linear polarization in the optical-to-radio bands are attributed to shocks propagating within the jet spine, in part, based on limited modelling invoking transverse shocks; new radiative transfer simulations allowing for shocks at arbitrary angle to the flow direction confirm this picture by reproducing the observed centimeter-band variations observed more generally, and are of current interest since these shocks may play a role in the -ray flaring detected by Fermi. Recent UMRAO multifrequency Stokes V studies of bright blazars identify the spectral variability properties of circular polarization for the first time and demonstrate that polarity flips are relatively common. All-Stokes data are consistent with the production of circular polarization by linear-to-circular mode conversion in a region that is at least partially selfabsorbed. Detailed analysis of single-epoch, multifrequency, all-Stokes VLBA observations of 3C 279 support this physical picture and are best explained by emission from an electron-proton plasma.

  17. Towards Assessing the Information Content of Dual-Polarization Radar Measurements

    Science.gov (United States)

    Giangrande, S. E.; McGraw, R. L.; Fierce, L.; Zhang, G.

    2016-12-01

    Improving utilization of dual polarization radar measurements, including for the retrieval of larger-scale rainfall accumulation, detailed phase partitioning and drop size distributions (DSDs), is one potential path toward developing or improving process-level cloud models and parameterizations for climate prediction. There are known and immediate demands for high-quality rainfall-accumulation maps to act as a key component for continuous climate-model-forcing datasets. Similarly, the monitoring of particle size and phase evolution may serve as key constraint for modeled deep convective processes. Whereas there is no shortage of dual-polarization retrieval methodologies for the key geophysical quantities of interest (e.g., precipitation estimates, DSD), less emphasis has been on the use of dual-polarization quantities as constraints for such retrievals. Here, we explore an application of linear programming to dual-polarization retrievals. This effort builds on Twomey's work, "Information content of remote sensing", which uses algebraic covariance matrix/eigenvalue analysis. Linear programming is used to perform geometric-type analysis (e.g., obtaining nested bounds to feasible sets of conditions consistent with the measurement constraints) beyond the capability of variance-based methods. Key motivating questions can be expressed as, `What are the upper and lower bounds on quantities of interest such as rainfall rate, consistent with a given set of dual polarization radar measurements?'

  18. Measurement of the tau polarization in Z → ττ decays with the ATLAS detector

    Energy Technology Data Exchange (ETDEWEB)

    Bechtle, Philip; Desch, Klaus; Schildgen, Lara; Wagner, Peter [University of Bonn (Germany)

    2016-07-01

    This talk summarizes the status of the tau polarization analysis which represents the first measurement of the tau polarization in Z → ττ decays at a hadron collider. In addition to the measurement of the tau polarization, the first ATLAS measurement of the effective Weinberg angle in third generation lepton coupling will be performed. The presented analysis focuses on the decay process Z → τ{sub lep}τ{sub had} in which the polarization of the hadronically decaying tau lepton is estimated from the energy asymmetry of the charged and neutral decay products. The presentation emphasizes the understanding of polarization-sensitive observables using sideband and control distributions from data. The main focus is placed on the event selection and the background estimation including data driven methods for the estimation of multijet and W+jets backgrounds. Furthermore, the extraction of a systematic uncertainty on the shape of the data driven estimate of the W+jets background is presented. The presented analysis is based on data collected with the ATLAS detector in 2012 at a center of mass energy of √(s) = 8 TeV with an integrated luminosity of 20.3 fb{sup -1}.

  19. Radiative Transfer Modeling of Radio-band Linear Polarization Observations as a Probe of the Physical Conditions in the Jets of Gamma-ray Flaring Blazars

    CERN Document Server

    Aller, Margo F; Aller, Hugh D; Hovatta, Talvikki; Ramakrishnan, Venkatessh

    2016-01-01

    Since the mid-1980s the shock-in-jet model has been the preferred paradigm to explain radio-band flaring in blazar jets. We describe our radiative transfer model incorporating relativistically-propagating shocks, and illustrate how the 4.8, 8, and 14.5 GHz linear polarization and total flux density data from the University of Michigan monitoring program, in combination with the model, constrain jet flow conditions and shock attributes. Results from strong Fermi-era flares in 4 blazars with widely-ranging properties are presented. Additionally, to investigate jet evolution on decadal time scales we analyze 3 outbursts in OT 081 spanning nearly 3 decades and find intrinsic changes attributable to flow changes at a common spatial location, or, alternatively, to a change in the jet segment viewed. The model's success in reproducing these data supports a scenario in which relativistic shocks compress a plasma with an embedded passive, initially-turbulent magnetic field, with additional ordered magnetic field compo...

  20. Squids, snakes, and polarimeters: A new technique for measuring the magnetic moments of polarized beams

    Energy Technology Data Exchange (ETDEWEB)

    Cameron, P.R.; Luccio, A.U.; Shea, T.J.; Tsoupas, N. [Brookhaven National Laboratory, Upton, New York 11973 (United States of America); Goldberg, D.A. [Lawrence Berkeley Laboratory, Berkeley, California (United States of America)

    1997-01-01

    Effective polarimetry at high energies in hadron and lepton synchrotrons has been a long-standing and difficult problem. In synchrotrons with polarized beams it is possible to cause the direction of the polarization vector of a given bunch to alternate at a frequency which is some subharmonic of the rotation frequency. This can result in the presence of lines in the beam spectrum which are due only to the magnetic moment of the beam and which are well removed from the various lines due to the charge of the beam. The magnitude of these lines can be calculated from first principles. They are many orders of magnitude weaker than the Schottky signals. Measurement of the magnitude of one of these lines would be an absolute measurement of beam polarization. For measuring magnetic field, the Superconducting Quantum Interference Device, or squid, is about five orders of magnitude more sensitive than any other transducer. Using a squid, such a measurement might be accomplished with the proper combination of shielding, pickup loop design, and filtering. The resulting instrument would be fast, non-destructive, and comparatively cheap. In addition, techniques developed in the creation of such an instrument could be used to measure the Schottky spectrum in unprecedented detail. We present specifics of a polarimeter design for the Relativistic Heavy Ion Collider (RHIC) and briefly discuss the possibility of using this technique to measure polarization at high-energy electron machines like LEP and HERA. {copyright} {ital 1997 American Institute of Physics.}

  1. A Precision Measurement of the Neutron Spin Structure Functions Using a Polarized HE-3 Target

    Energy Technology Data Exchange (ETDEWEB)

    Smith, T

    2003-11-05

    This thesis describes a precision measurement of the neutron spin dependent structure function, g{sub 1}{sup n}(x). The measurement was made by the E154 collaboration at SLAC using a longitudinally polarized, 48.3 GeV electron beam, and a {sup 3}He target polarized by spin exchange with optically pumped rubidium. A target polarization as high as 50% was achieved. The elements of the experiment which pertain to the polarized {sup 3}He target will be described in detail in this thesis. To achieve a precision measurement, it has been necessary to minimize the systematic error from the uncertainty in the target parameters. All of the parameters of the target have been carefully measured, and the most important parameters of the target have been measured using multiple techniques. The polarization of the target was measured using nuclear magnetic resonance techniques, and has been calibrated using both proton NMR and by measuring the shift of the Rb Zeeman resonance frequency due to the {sup 3}He polarization. The fraction of events which originated in the {sup 3}He, as measured by the spectrometers, has been determined using a physical model of the target and the spectrometers. It was also measured during the experiment using a variable pressure {sup 3}He reference cell in place of the polarized {sup 3}He target. The spin dependent structure function g{sub 1}{sup n}(z) was measured in the Bjorken x range of 0.014 < x < 0.7 with an average Q{sup 2} of 5 (GeV/c){sup 2}. One of the primary motivations for this experiment was to test the Bjorken sum rule. Because the experiment had smaller statistical errors and a broader kinematic coverage than previous experiments, the behavior of the spin structure function g{sub 1}{sup n}(x) could be studied in detail at low values of the Bjorken scaling variable x. It was found that g{sub 1}{sup n}(x) has a strongly divergent behavior at low values of x, calling into question the methods commonly used to extrapolate the value of g

  2. Radio Band Observations of Blazar Variability

    CERN Document Server

    Aller, Margo F; Hughes, Philip A

    2010-01-01

    The properties of blazar variability in the radio band are studied using the unique combination of temporal resolution from single dish monitoring and spatial resolution from VLBA imaging; such measurements, now available in all four Stokes parameters, together with theoretical simulations, identify the origin of radio band variability and probe the characteristics of the radio jet where the broadband blazar emission originates. Outbursts in total flux density and linear polarization in the optical-to-radio bands are attributed to shocks propagating within the jet spine, in part based on limited modeling invoking transverse shocks; new radiative transfer simulations allowing for shocks at arbitrary angle to the flow direction confirm this picture by reproducing the observed centimeter-band variations observed more generally, and are of current interest since these shocks may play a role in the gamma-ray flaring detected by Fermi. Recent UMRAO multifrequency Stokes V studies of bright blazars identify the spec...

  3. Radiative transfer with POLARIS. I. Analysis of magnetic fields through synthetic dust continuum polarization measurements

    Science.gov (United States)

    Reissl, S.; Wolf, S.; Brauer, R.

    2016-09-01

    Aims: We present POLARIS (POLArized RadIation Simulator), a newly developed three-dimensional Monte-Carlo radiative transfer code. POLARIS was designed to calculate dust temperature, polarization maps, and spectral energy distributions. It is optimized to handle data that results from sophisticated magneto-hydrodynamic simulations. The main purpose of the code is to prepare and analyze multi-wavelength continuum polarization measurements in the context of magnetic field studies in the interstellar medium. An exemplary application is the investigation of the role of magnetic fields in star formation processes. Methods: We combine currently discussed state-of-the-art grain alignment theories with existing dust heating and polarization algorithms. We test the POLARIS code on multiple scales in complex astrophysical systems that are associated with different stages of star formation. POLARIS uses the full spectrum of dust polarization mechanisms to trace the underlying magnetic field morphology. Results: Resulting temperature distributions are consistent with the density and position of radiation sources resulting from magneto-hydrodynamic (MHD) - collapse simulations. The calculated layers of aligned dust grains in the considered cirumstellar disk models are in excellent agreement with theoretical predictions. Finally, we compute unique patterns in synthetic multi-wavelength polarization maps that are dependent on applied dust-model and grain-alignment theory in analytical cloud models.

  4. A measurement of parity-violating gamma-ray asymmetries in polarized cold neutron capture on 35Cl, 113Cd, and 139La

    CERN Document Server

    Mitchell, G S; Bowman, J D; Chupp, T E; Coulter, K P; Gericke, M T W; Jones, G L; Leuschner, M B; Nann, H; Page, S A; Penttila, S I; Smith, T B; Snow, W M; Wilburn, W S

    2004-01-01

    An apparatus for measuring parity-violating asymmetries in gamma-ray emission following polarized cold neutron capture was constructed as a 1/10th scale test of the design for the forthcoming n+p->d+gamma experiment at LANSCE. The elements of the polarized neutron beam, including a polarized 3He neutron spin filter and a radio frequency neutron spin rotator, are described. Using CsI(Tl) detectors and photodiode current mode readout, measurements were made of asymmetries in gamma-ray emission following neutron capture on 35Cl, 113Cd, and 139La targets. Upper limits on the parity-allowed asymmetry $s_n \\cdot (k_{\\gamma} \\times k_n)$ were set at the level of 7 x 10^-6 for all three targets. Parity-violating asymmetries $s_n \\cdot k_{\\gamma}$ were observed in 35Cl, A_gamma = (-29.1 +- 6.7) x 10^-6, and 139La, A_gamma = (-15.5 +- 7.1) x 10^-6, values consistent with previous measurements.

  5. Aspect sensitivity measurements of polar mesosphere summer echoes using coherent radar imaging

    Directory of Open Access Journals (Sweden)

    P. B. Chilson

    Full Text Available The Esrange VHF radar (ESRAD, located in northern Sweden (67.88° N, 21.10° E, has been used to investigate polar mesosphere summer echoes (PMSE. During July and August of 1998, coherent radar imaging (CRI was used to study the dynamic evolution of PMSE with high temporal and spatial resolution. A CRI analysis provides an estimate of the angular brightness distribution within the radar’s probing volume. The brightness distribution is directly related to the radar reflectivity. Consequently, these data are used to investigate the aspect sensitivity of PMSE. In addition to the CRI analysis, the full correlation analysis (FCA is used to derive estimates of the prevailing three-dimensional wind associated with the observed PMSE. It is shown that regions within the PMSE with enhanced aspect sensitivity have a correspondingly high signal-to-noise ratio (SNR. Although this relationship has been investigated in the past, the present study allows for an estimation of the aspect sensitivity independent of the assumed scattering models and avoids the complications of comparing echo strengths from vertical and off-vertical beams over large horizontal separations, as in the Doppler Beam Swinging (DBS method. Regions of enhanced aspect sensitivity were additionally shown to correlate with the wave-perturbation induced downward motions of air parcels embedded in the PMSE.

    Key words. Ionosphere (polar ionosphere Meteorology and Atmospheric Dynamics (middle atmosphere dynamics Radio Science (Interferometry

  6. Measuring top-quark polarization in top-pair + missing-energy events.

    Science.gov (United States)

    Berger, Edmond L; Cao, Qing-Hong; Yu, Jiang-Hao; Zhang, Hao

    2012-10-12

    The polarization of a top quark can be sensitive to new physics beyond the standard model. Since the charged lepton from top-quark decay is maximally correlated with the top-quark spin, it is common to measure the polarization from the distribution in the angle between the charged lepton and the top-quark directions. We propose a novel method based on the charged lepton energy fraction and illustrate the method with a detailed simulation of top-quark pairs produced in supersymmetric top squark pair production. We show that the lepton energy ratio distribution that we define is very sensitive to the top-quark polarization but insensitive to the precise measurement of the top-quark energy.

  7. Rocket measurements within a polar cap arc - Plasma, particle, and electric circuit parameters

    Science.gov (United States)

    Weber, E. J.; Ballenthin, J. O.; Basu, S.; Carlson, H. C.; Hardy, D. A.; Maynard, N. C.; Kelley, M. C.; Fleischman, J. R.; Pfaff, R. F.

    1989-01-01

    Results are presented from the Polar Ionospheric Irregularities Experiment (PIIE), conducted from Sondrestrom, Greenland, on March 15, 1985, designed for an investigation of processes which lead to the generation of small-scale (less than 1 km) ionospheric irregularities within polar-cap F-layer auroras. An instrumented rocket was launched into a polar cap F layer aurora to measure energetic electron flux, plasma, and electric circuit parameters of a sun-aligned arc, coordinated with simultaneous measurements from the Sondrestrom incoherent scatter radar and the AFGL Airborne Ionospheric Observatory. Results indicated the existence of two different generation mechanisms on the dawnside and duskside of the arc. On the duskside, parameters are suggestive of an interchange process, while on the dawnside, fluctuation parameters are consistent with a velocity shear instability.

  8. An imaging spectro-polarimeter for measuring hemispherical spectrally resolved down-welling sky polarization

    Science.gov (United States)

    Chenault, David B.; Pezzaniti, J. L.; Roche, Michael; Hyatt, Brian

    2016-05-01

    A full sky imaging spectro-polarimeter has been developed that measures spectrally resolved (~2.5 nm resolution) radiance and polarization (𝑠0, 𝑠1, 𝑠2 Stokes Elements) of natural sky down-welling over approximately 2π sr between 400nm and 1000nm. The sensor is based on a scanning push broom hyperspectral imager configured with a continuously rotating polarizer (sequential measurement in time polarimeter). Sensor control and processing software (based on Polaris Sensor Technologies Grave' camera control software) has a straight-forward and intuitive user interface that provides real-time updated sky down-welling spectral radiance/polarization maps and statistical analysis tools.

  9. Quantitative measurement of vocal fold vibration in male radio performers and healthy controls using high-speed videoendoscopy.

    Directory of Open Access Journals (Sweden)

    Samantha Warhurst

    Full Text Available Acoustic and perceptual studies show a number of differences between the voices of radio performers and controls. Despite this, the vocal fold kinematics underlying these differences are largely unknown. Using high-speed videoendoscopy, this study sought to determine whether the vocal vibration features of radio performers differed from those of non-performing controls.Using high-speed videoendoscopy, recordings of a mid-phonatory/i/ in 16 male radio performers (aged 25-52 years and 16 age-matched controls (aged 25-52 years were collected. Videos were extracted and analysed semi-automatically using High-Speed Video Program, obtaining measures of fundamental frequency (f0, open quotient and speed quotient. Post-hoc analyses of sound pressure level (SPL were also performed (n = 19. Pearson's correlations were calculated between SPL and both speed and open quotients.Male radio performers had a significantly higher speed quotient than their matched controls (t = 3.308, p = 0.005. No significant differences were found for f0 or open quotient. No significant correlation was found between either open or speed quotient with SPL.A higher speed quotient in male radio performers suggests that their vocal fold vibration was characterised by a higher ratio of glottal opening to closing times than controls. This result may explain findings of better voice quality, higher equivalent sound level and greater spectral tilt seen in previous research. Open quotient was not significantly different between groups, indicating that the durations of complete vocal fold closure were not different between the radio performers and controls. Further validation of these results is required to determine the aetiology of the higher speed quotient result and its implications for voice training and clinical management in performers.

  10. Radio emission of highly inclined cosmic ray air showers measured with LOPES

    CERN Document Server

    Petrovic, Jelena; Asch, T; Badea, F; Bähren, L; Bekk, K; Bercuci, A; Bertaina, M; Biermann, P L; Blumer, J; Bozdog, H; Brancus, I M; Bruggemann, M; Buchholz, P; Buitink, S; Butcher, H; Chiavassa, A; Cossavella, F; Daumiller, K; Di Pierro, F; Doll, P; Engel, R; Falcke, H; Gemmeke, H; Ghia, P L; Glasstetter, R; Grupen, C; Haungs, A; Heck, D; Hörandel, J R; Horneffer, A; Huege, T; Kampert, K H; Kolotaev, Yu; Krömer, O; Kuijpers, J; Lafebre, S; Mathes, H J; Mayer, H J; Meurer, C; Milke, J; Mitrica, B; Morello, C; Navarra, G; Nehls, S; Nigl, A; Obenland, R; Oehlschläger, J; Ostapchenko, S; Over, S; Petcu, M; Pierog, T; Plewnia, S; Rebel, H; Risse, A; Roth, M; Schieler, H; Sima, O; Singh, K; Stumpert, M; Toma, G; Trinchero, G C; Ulrich, H; Van Buren, J; Walkowiak, W; Weindl, A; Wochele, J; Zabierowski, J; Zensus, J A; Zimmermann, D

    2006-01-01

    LOPES-10 (the first phase of LOPES, consisting of 10 antennas) detected a significant number of cosmic ray air showers with a zenith angle larger than 50$^{\\circ}$, and many of these have very high radio field strengths. The most inclined event that has been detected with LOPES-10 has a zenith angle of almost 80$^{\\circ}$. This is proof that the new technique is also applicable for cosmic ray air showers with high inclinations, which in the case that they are initiated close to the ground, can be a signature of neutrino events.Our results indicate that arrays of simple radio antennas can be used for the detection of highly inclined air showers, which might be triggered by neutrinos. In addition, we found that the radio pulse height (normalized with the muon number) for highly inclined events increases with the geomagnetic angle, which confirms the geomagnetic origin of radio emission in cosmic ray air showers.

  11. A radio-polarisation and rotation measure study of the Gum Nebula and its environment

    CERN Document Server

    Purcell, C R; Sun, X H; Carretti, E; Bernardi, G; Haverkorn, M; Kesteven, M J; Poppi, S; Schnitzeler, D H F M; Staveley-Smith, L

    2015-01-01

    The Gum Nebula is 36 degree wide shell-like emission nebula at a distance of only 450 pc. It has been hypothesised to be an old supernova remnant, fossil HII region, wind-blown bubble, or combination of multiple objects. Here we investigate the magneto-ionic properties of the nebula using data from recent surveys: radio-continuum data from the NRAO VLA and S-band Parkes All Sky Surveys, and H-alpha data from the Southern H-Alpha Sky Survey Atlas. We model the upper part of the nebula as a spherical shell of ionised gas expanding into the ambient medium. We perform a maximum-likelihood Markov chain Monte-Carlo fit to the NVSS rotation measure data, using the H-halpha data to constrain average electron density in the shell $n_e$. Assuming a latitudinal background gradient in RM we find $n_e=1.3^{+0.4}_{-0.4} {\\rm cm}^{-3}$, angular radius $\\phi_{\\rm outer}=22.7^{+0.1}_{-0.1} {\\rm deg}$, shell thickness $dr=18.5^{+1.5}_{-1.4} {\\rm pc}$, ambient magnetic field strength $B_0=3.9^{+4.9}_{-2.2} \\mu{\\rm G}$ and warm ...

  12. RECONCILING MODELS OF LUMINOUS BLAZARS WITH MAGNETIC FLUXES DETERMINED BY RADIO CORE-SHIFT MEASUREMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Nalewajko, Krzysztof; Begelman, Mitchell C. [JILA, University of Colorado and National Institute of Standards and Technology, 440 UCB, Boulder, CO 80309 (United States); Sikora, Marek, E-mail: knalew@stanford.edu [Nicolaus Copernicus Astronomical Center, Bartycka 18, 00-716 Warsaw (Poland)

    2014-11-20

    Estimates of magnetic field strength in relativistic jets of active galactic nuclei, obtained by measuring the frequency-dependent radio core location, imply that the total magnetic fluxes in those jets are consistent with the predictions of the magnetically arrested disk (MAD) scenario of jet formation. On the other hand, the magnetic field strength determines the luminosity of the synchrotron radiation, which forms the low-energy bump of the observed blazar spectral energy distribution (SED). The SEDs of the most powerful blazars are strongly dominated by the high-energy bump, which is most likely due to the external radiation Compton mechanism. This high Compton dominance may be difficult to reconcile with the MAD scenario, unless (1) the geometry of external radiation sources (broad-line region, hot-dust torus) is quasi-spherical rather than flat, or (2) most gamma-ray radiation is produced in jet regions of low magnetization, e.g., in magnetic reconnection layers or in fast jet spines.

  13. A computationally assisted spectroscopic technique to measure secondary electron emission coefficients in radio frequency plasmas

    Science.gov (United States)

    Daksha, M.; Berger, B.; Schuengel, E.; Korolov, I.; Derzsi, A.; Koepke, M.; Donkó, Z.; Schulze, J.

    2016-06-01

    A computationally assisted spectroscopic technique to measure secondary electron emission coefficients (γ-CAST) in capacitively-coupled radio-frequency plasmas is proposed. This non-intrusive, sensitive diagnostic is based on a combination of phase resolved optical emission spectroscopy and particle-based kinetic simulations. In such plasmas (under most conditions in electropositive gases) the spatio-temporally resolved electron-impact excitation/ionization rate features two distinct maxima adjacent to each electrode at different times within each RF period. While one maximum is the consequence of the energy gain of electrons due to sheath expansion, the second maximum is produced by secondary electrons accelerated towards the plasma bulk by the sheath electric field at the time of maximum voltage drop across the adjacent sheath. Due to these different excitation/ionization mechanisms, the ratio of the intensities of these maxima is very sensitive to the secondary electron emission coefficient γ. This sensitvity, in turn, allows γ to be determined by comparing experimental excitation profiles and simulation data obtained with various γ-coefficients. The diagnostic, tested here in a geometrically symmetric argon discharge, yields an effective secondary electron emission coefficient of γ =0.066+/- 0.01 for stainless steel electrodes.

  14. Measuring the speed of light with ultra-compact radio quasars

    CERN Document Server

    Cao, Shuo; Jackson, John; Zheng, Xiaogang; Zhu, Zong-Hong

    2016-01-01

    In this paper, based on a 2.29 GHz VLBI all-sky survey of 613 milliarcsecond ultra-compact radio sources with $0.0035measured for quasars extending to hi...

  15. Reconciling models of luminous blazars with magnetic fluxes determined by radio core shift measurements

    CERN Document Server

    Nalewajko, Krzysztof; Begelman, Mitchell C

    2014-01-01

    Estimates of magnetic field strength in relativistic jets of active galactic nuclei (AGN), obtained by measuring the frequency-dependent radio core location, imply that the total magnetic fluxes in those jets are consistent with the predictions of the magnetically-arrested disk (MAD) scenario of jet formation. On the other hand, the magnetic field strength determines the luminosity of the synchrotron radiation, which forms the low-energy bump of the observed blazar spectral energy distribution (SED). The SEDs of the most powerful blazars are strongly dominated by the high-energy bump, which is most likely due to the external radiation Compton (ERC) mechanism. This high Compton dominance may be difficult to reconcile with the MAD scenario, unless 1) the geometry of external radiation sources (broad-line region, hot-dust torus) is quasi-spherical rather than flat, or 2) most gamma-ray radiation is produced in jet regions of low magnetization, e.g., in magnetic reconnection layers or in fast jet spines.

  16. Revisiting the radio interferometer measurement equation. I. A full-sky Jones formalism

    CERN Document Server

    Smirnov, Oleg M

    2011-01-01

    Since its formulation by Hamaker et al., the radio interferometer measurement equation (RIME) has provided a rigorous mathematical basis for the development of novel calibration methods and techniques, including various approaches to the problem of direction-dependent effects (DDEs). This series of papers aims to place recent developments in the treatment of DDEs into one RIME-based mathematical framework, and to demonstrate the ease with which the various effects can be described and understood. It also aims to show the benefits of a RIME-based approach to calibration. Paper I re-derives the RIME from first principles, extends the formalism to the full-sky case, and incorporates DDEs. Paper II then uses the formalism to describe self-calibration, both with a full RIME, and with the approximate equations of older software packages, and shows how this is affected by DDEs. It also gives an overview of real-life DDEs and proposed methods of dealing with them. Applying this to WSRT data (Paper III) results in a n...

  17. Measuring the speed of light with ultra-compact radio quasars

    Science.gov (United States)

    Cao, Shuo; Biesiada, Marek; Jackson, John; Zheng, Xiaogang; Zhao, Yuhang; Zhu, Zong-Hong

    2017-02-01

    In this paper, based on a 2.29 GHz VLBI all-sky survey of 613 milliarcsecond ultra-compact radio sources with 0.0035sample which can serve as individual standard rulers in cosmology. If the linear size of the compact structure is assumed to depend on source luminosity and redshift as lm=l Lβ (1+z)n, only intermediate-luminosity quasars (1027 W/Hzpopulation of such rulers with fixed characteristic length l=11.42 pc. With a sample of 120 such sources covering the redshift range 00.46measured for quasars extending to high redshifts (0z~ 3.), we reconstruct the DA(z) function using the technique of Gaussian processes. This allows us to identify the redshift corresponding to the maximum of the DA(z) function: 0zm=1.7 and the corresponding angular diameter distance DA(zm)=1719.01±43.46 Mpc. Similar reconstruction of the expansion rate function H(z) based on the data from cosmic chronometers and BAO gives us H(zm)=176.77±6.11 km sec‑1 Mpc‑1. These measurements are used to estimate the speed of light: c=3.039(±0.180)× 105 km/s. This is the first measurement of the speed of light in a cosmological setting referring to the distant past.

  18. A Measurement of the Millimeter Emission and the Sunyaev-Zel'dovich Effect Associated with Low-Frequency Radio Sources

    Science.gov (United States)

    Gralla, Megan B.; Crichton, Devin; Marriage, Tobias; Mo, Wenli; Aguirre, Paula; Addison, Graeme E.; Asboth, V.; Battaglia, Nick; Bock, James; Bond, J. Richard; hide

    2014-01-01

    We present a statistical analysis of the millimeter-wavelength properties of 1.4 GHz-selected sources and a detection of the Sunyaev-Zel'dovich effect associated with the halos that host them. We stack data at 148, 218 and 277 GHz from the Atacama Cosmology Telescope at the positions of a large sample of radio AGN selected at 1.4 GHz. The thermal Sunyaev-Zel'dovich (SZ) effect associated with the halos that host the AGN is detected at the 5 sigma level through its spectral signature, representing a statistical detection of the SZ effect in some of the lowest mass halos (average M(sub 200) approximately equals 10(sup 13) solar mass h(sub 70)(exp -1) ) studied to date. The relation between the SZ effect and mass (based on weak lensing measurements of radio galaxies) is consistent with that measured by Planck for local bright galaxies. In the context of galaxy evolution models, this study confirms that galaxies with radio AGN also typically support hot gaseous halos. Adding Herschel observations allows us to show that the SZ signal is not significantly contaminated by dust emission. Finally, we analyze the contribution of radio sources to the angular power spectrum of the cosmic microwave background.

  19. Characterization of highly scattering media by measurement of diffusely backscattered polarized light

    Energy Technology Data Exchange (ETDEWEB)

    Hielscher, A.H.; Mourant, J.R.; Bigio, I.J.

    2000-01-04

    An apparatus and method for recording spatially dependent intensity patterns of polarized light that is diffusely backscattered from highly scattering media are described. These intensity patterns can be used to differentiate different turbid media, such as polystyrene-sphere and biological-cell suspensions. Polarized light from a He-Ne laser ({lambda} = 543 nm) is focused onto the surface of the scattering medium, and a surface area of approximately 4 x 4 cm centered on the light input point is imaged through polarization analysis optics onto a CCD camera. A variety of intensity patterns may be observed by varying the polarization state of the incident laser light and changing the analyzer configuration to detect different polarization components of the backscattered light. Experimental results for polystyrene-sphere and intralipid suspensions demonstrate that the radial and azimuthal variations of the observed pattern depend on the concentration, size, and anisotropy factor, g, of the particles constituting the scattering medium. Measurements performed on biological cell suspensions show that intensity patterns can be used to differentiate between suspensions of cancerous and non-cancerous cells. Introduction of the Mueller-matrix for diffusely backscattered light, permits the selection of a subset of measurements which comprehensively describes the optical properties of backscattering media.

  20. Characterization of highly scattering media by measurement of diffusely backscattered polarized light

    Energy Technology Data Exchange (ETDEWEB)

    Hielscher, Andreas H. (Brooklyn, NY); Mourant, Judith R. (Los Alamos, NM); Bigio, Irving J. (Los Alamos, NM)

    2000-01-01

    An apparatus and method for recording spatially dependent intensity patterns of polarized light that is diffusely backscattered from highly scattering media are described. These intensity patterns can be used to differentiate different turbid media, such as polystyrene-sphere and biological-cell suspensions. Polarized light from a He-Ne laser (.lambda.=543 nm) is focused onto the surface of the scattering medium, and a surface area of approximately 4.times.4 cm centered on the light input point is imaged through polarization analysis optics onto a CCD camera. A variety of intensity patterns may be observed by varying the polarization state of the incident laser light and changing the analyzer configuration to detect different polarization components of the backscattered light. Experimental results for polystyrene-sphere and Intralipid suspensions demonstrate that the radial and azimuthal variations of the observed pattern depend on the concentration, size, and anisotropy factor, g, of the particles constituting the scattering medium. Measurements performed on biological cell suspensions show that intensity patterns can be used to differentiate between suspensions of cancerous and non-cancerous cells. Introduction of the Mueller-matrix for diffusely backscattered light, permits the selection of a subset of measurements which comprehensively describes the optical properties of backscattering media.

  1. Measurement of azimuthal asymmetries associated with deeply virtual Compton scattering on a longitudinally polarized deuterium target

    Energy Technology Data Exchange (ETDEWEB)

    Airapetian, A. [Giessen Univ. (Germany). Physikalisches Inst.; Michigan Univ., Ann Arbor, MI (United States). Randall Laboratory of Physics; Akopov, N. [Yerevan Physical Institute, Yerevan (Armenia); Akopov, Z. [DESY Hamburg (DE)] (and others)

    2010-08-15

    Azimuthal asymmetries in exclusive electroproduction of a real photon from a longitudinally polarized deuterium target are measured with respect to target polarization alone and with respect to target polarization combined with beam helicity and/or beam charge. The asymmetries appear in the distribution of the real photons in the azimuthal angle {phi} around the virtual photon direction, relative to the lepton scattering plane. The asymmetries arise from the deeply virtual Compton scattering process and its interference with the Bethe-Heitler process. The results for the beam-charge and beam-helicity asymmetries from a tensor polarized deuterium target with vanishing vector polarization are shown to be compatible with those from an unpolarized deuterium target, which is expected for incoherent scattering dominant at larger momentum transfer. Furthermore, the results for the single target-spin asymmetry and for the double-spin asymmetry are found to be compatible with the corresponding asymmetries previously measured on a hydrogen target. For coherent scattering on the deuteron at small momentum transfer to the target, these findings imply that the tensor contribution to the cross section is small. Furthermore, the tensor asymmetry is found to be compatible with zero. (orig.)

  2. Measurements of the Proton Spin Polarizabilities with Double-Polarized Compton Scattering

    CERN Document Server

    Martel, P P; Aguar-Bartolome, P; Ahrens, J; Akondi, C S; Annand, J R M; Arends, H J; Barnes, W; Beck, R; Bernstein, A; Borisov, N; Braghieri, A; Briscoe, W J; Cherepnya, S; Collicott, C; Costanza, S; Denig, A; Dieterle, M; Downie, E J; Fil'kov, L V; Garni, S; Glazier, D I; Gradl, W; Gurevich, G; Barrientos, P Hall; Hamilton, D; Hornidge, D; Howdle, D; Huber, G M; Jude, T C; Kaeser, A; Kashevarov, V L; Keshelashvili, I; Kondratiev, R; Korolija, M; Krusche, B; Lazarev, A; Lisin, V; Livingston, K; MacGregor, I J D; Mancell, J; Manley, D M; Meyer, W; Middleton, D G; Mushkarenkov, A; Nefkens, B M K; Neganov, A; Nikolaev, A; Oberle, M; Spina, H Ortega; Ostrick, M; Ott, P; Otte, P B; Oussena, B; Pedroni, P; Polonski, A; Polyansky, V; Prakhov, S; Rajabi, A; Reicherz, G; Rostomyan, T; Sarty, A; Schrauf, S; Schumann, S; Sikora, M H; Starostin, A; Steffen, O; Strakovsky, I I; Strub, T; Supek, I; Thiel, M; Tiator, L; Thomas, A; Unverzagt, M; Usov, Y; Watts, D P; Witthauer, L; Werthmüller, D; Wolfes, M

    2014-01-01

    The spin polarizabilities of the nucleon describe how the spin of the nucleon responds to an incident polarized photon. The most model-independent way to measure the nucleon spin polarizabilities is through polarized Compton scattering. Double-polarized Compton scattering asymmetries on the proton were measured in the $\\Delta(1232)$ region using circularly polarized incident photons and a transversely polarized proton target at the Mainz Microtron. Fits to asymmetry data were performed using a dispersion model calculation and a baryon chiral perturbation theory calculation, and a separation of all four proton spin polarizabilities in the multipole basis was achieved. The analysis based on a dispersion model calculation yields $\\gamma_{E1E1} = -3.5 \\pm 1.2$, $\\gamma_{M1M1}= 3.16 \\pm 0.85$, $\\gamma_{E1M2} = -0.7 \\pm 1.2$, and $\\gamma_{M1E2} = 1.99 \\pm 0.29$, in units of $10^{-4}$ fm$^4$.

  3. Optimal distribution of integration time for intensity measurements in degree of linear polarization polarimetry.

    Science.gov (United States)

    Li, Xiaobo; Hu, Haofeng; Liu, Tiegen; Huang, Bingjing; Song, Zhanjie

    2016-04-04

    We consider the degree of linear polarization (DOLP) polarimetry system, which performs two intensity measurements at orthogonal polarization states to estimate DOLP. We show that if the total integration time of intensity measurements is fixed, the variance of the DOLP estimator depends on the distribution of integration time for two intensity measurements. Therefore, by optimizing the distribution of integration time, the variance of the DOLP estimator can be decreased. In this paper, we obtain the closed-form solution of the optimal distribution of integration time in an approximate way by employing Delta method and Lagrange multiplier method. According to the theoretical analyses and real-world experiments, it is shown that the variance of the DOLP estimator can be decreased for any value of DOLP. The method proposed in this paper can effectively decrease the measurement variance and thus statistically improve the measurement accuracy of the polarimetry system.

  4. Using FTIR measurements of stratospheric composition to identify midlatitude polar vortex intrusions over Toronto

    Science.gov (United States)

    Whaley, C.; Strong, K.; Adams, C.; Bourassa, A. E.; Daffer, W. H.; Degenstein, D. A.; Fast, H.; Fogal, P. F.; Manney, G. L.; Mittermeier, R. L.; Pavlovic, B.; Wiacek, A.

    2013-11-01

    Using 11 years of trace gas measurements made at the University of Toronto Atmospheric Observatory (43.66°N, 79.40°W) and Environment Canada's Centre for Atmospheric Research Experiments (44.23°N, 79.78°W), along with derived meteorological products, we identify a number of polar intrusion events, which are excursions of the polar vortex or filaments from the polar vortex extending down to midlatitudes. These events are characterized by enhanced stratospheric columns (12-50 km) of hydrogen fluoride (HF), by diminished stratospheric columns of nitrous oxide (N2O), and by a scaled potential vorticity above 1.2 × 10-4s-1. The events comprise 16%of winter/spring (November to April inclusive) Fourier transform infrared (FTIR) spectroscopic measurements from January 2002 to March 2013, and we find at least two events per year. The events are corroborated by Modèle Isentrope du transport Méso-échelle de l'Ozone Stratosphérique par Advection, Modern-Era Retrospective Analysis for Research and Applications potential vorticity maps, and Global Modeling Initiative N2O maps. During polar intrusion events, the stratospheric ozone (O3) columns over Toronto are usually greater than when there is no event. Our O3 measurements agree with the Optical Spectrograph and Infrared Imaging System satellite instrument and are further verified with the Earth Probe Total Ozone Mapping Spectrometer and Ozone Monitoring Instrument satellite observations. We find six cases out of 53 for which chemical O3depletion within the polar vortex led to a reduction in stratospheric O3 columns over Toronto. We have thus identified a dynamical cause for most of the winter/spring variability of stratospheric trace gas columns observed at our midlatitude site. While there have been a number of prior polar intrusion studies, this is the first study to report in the context of 11 years of ground-based FTIR column measurements, providing insight into the frequency of midlatitude polar vortex intrusions

  5. A measurement of the absolute neutron beam polarization produced by an optically pumped sup 3 He neutron spin filter

    CERN Document Server

    Rich, D R; Crawford, B E; Delheij, P P J; Espy, M A; Haseyama, T; Jones, G; Keith, C D; Knudson, J; Leuschner, M B; Masaike, A; Masuda, Y; Matsuda, Y; Penttilae, S I; Pomeroy, V R; Smith, D A; Snow, W M; Szymanski, J J; Stephenson, S L; Thompson, A K; Yuan, V

    2002-01-01

    The capability of performing accurate absolute measurements of neutron beam polarization opens a number of exciting opportunities in fundamental neutron physics and in neutron scattering. At the LANSCE pulsed neutron source we have measured the neutron beam polarization with an absolute accuracy of 0.3% in the neutron energy range from 40 meV to 10 eV using an optically pumped polarized sup 3 He spin filter and a relative transmission measurement technique. sup 3 He was polarized using the Rb spin-exchange method. We describe the measurement technique, present our results, and discuss some of the systematic effects associated with the method.

  6. Measuring the self-healing of the spatially inhomogeneous states of polarization of vector Bessel beams

    CSIR Research Space (South Africa)

    Milione, G

    2015-02-01

    Full Text Available , using a spatial light modulator in concert with a liquid crystal q-plate. As a proof of principle, their intensities and spatially inhomogeneous states of polarization were experimentally measured using Stokes polarimetry as they propagated through two...

  7. Precision Neutral Current Asymmetry Parameter Measurements from the Tau Polarization at LEP

    CERN Document Server

    Abbiendi, G.; Akesson, P.F.; Alexander, G.; Allison, John; Anagnostou, G.; Anderson, K.J.; Arcelli, S.; Asai, S.; Axen, D.; Azuelos, G.; Bailey, I.; Ball, A.H.; Barberio, E.; Barlow, Roger J.; Batley, R.J.; Behnke, T.; Bell, Kenneth Watson; Bella, G.; Bellerive, A.; Benelli, G.; Bethke, S.; Biebel, O.; Bloodworth, I.J.; Boeriu, O.; Bock, P.; Bohme, J.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Brigliadori, L.; Brown, Robert M.; Burckhart, H.J.; Cammin, J.; Capiluppi, P.; Carnegie, R.K.; Caron, B.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Clarke, P.E.L.; Clay, E.; Cohen, I.; Couchman, J.; Csilling, A.; Cuffiani, M.; Dado, S.; Dallavalle, G.Marco; Dallison, S.; De Roeck, A.; De Wolf, E.A.; Dervan, P.; Desch, K.; Dienes, B.; Dixit, M.S.; Donkers, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Estabrooks, P.G.; Etzion, E.; Fabbri, F.; Fanti, M.; Feld, L.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Furtjes, A.; Futyan, D.I.; Gagnon, P.; Gary, J.W.; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Glenzinski, D.; Goldberg, J.; Grandi, C.; Graham, K.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Gupta, A.; Hajdu, C.; Hanson, G.G.; Harder, K.; Harel, A.; Harin-Dirac, M.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Hensel, C.; Herten, G.; Heuer, R.D.; Hill, J.C.; Hoffman, Kara Dion; Homer, R.J.; Honma, A.K.; Horvath, D.; Hossain, K.R.; Howard, R.; Huntemeyer, P.; Igo-Kemenes, P.; Ishii, K.; Jawahery, A.; Jeremie, H.; Jones, C.R.; Jovanovic, P.; Junk, T.R.; Kanaya, N.; Kanzaki, J.; Karapetian, G.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kim, D.H.; Klein, K.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Kokott, T.P.; Komamiya, S.; Kowalewski, Robert V.; Kamer, T.; Kress, T.; Krieger, P.; von Krogh, J.; Krop, D.; Kuhl, T.; Kupper, M.; Kyberd, P.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Lawson, I.; Layter, J.G.; Leins, A.; Lellouch, D.; Letts, J.; Levinson, L.; Liebisch, R.; Lillich, J.; Littlewood, C.; Lloyd, A.W.; Lloyd, S.L.; Loebinger, F.K.; Long, G.D.; Losty, M.J.; Lu, J.; Ludwig, J.; Macchiolo, A.; Macpherson, A.; Mader, W.; Marcellini, S.; Marchant, T.E.; Martin, A.J.; Martin, J.P.; Martinez, G.; Mashimo, T.; Mattig, Peter; McDonald, W.John; McKenna, J.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Mendez-Lorenzo, P.; Menges, W.; Merritt, F.S.; Mes, H.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mohr, W.; Montanari, A.; Mori, T.; Nagai, K.; Nakamura, I.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oakham, F.G.; Odorici, F.; Oh, A.; Okpara, A.; Oreglia, M.J.; Orito, S.; Pahl, C.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poli, B.; Polok, J.; Pooth, O.; Quadt, A.; Rabbertz, K.; Rembser, C.; Renkel, P.; Rick, H.; Rodning, N.; Roney, J.M.; Rosati, S.; Roscoe, K.; Rossi, A.M.; Rozen, Y.; Runge, K.; Runolfsson, O.; Rust, D.R.; Sachs, K.; Saeki, T.; Sahr, O.; Sarkisian, E.K.G.; Sbarra, C.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schroder, Matthias; Schumacher, M.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Siroli, G.P.; Skuja, A.; Smith, A.M.; Snow, G.A.; Sobie, R.; Soldner-Rembold, S.; Spagnolo, S.; Spano, F.; Sproston, M.; Stahl, A.; Stephens, K.; Strom, David M.; Strohmer, R.; Stumpf, L.; Surrow, B.; Talbot, S.D.; Tarem, S.; Tasevsky, M.; Taylor, R.J.; Teuscher, R.; Thomas, J.; Thomson, M.A.; Torrence, E.; Towers, S.; Toya, D.; Trefzger, T.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Vachon, B.; Vollmer, C.F.; Vannerem, P.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Waller, D.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wetterling, D.; White, J.S.; Wilson, G.W.; Wilson, J.A.; Wyatt, T.R.; Yamashita, S.; Zacek, V.; Zer-Zion, D.

    2001-01-01

    Measurements of the tau lepton polarization and forward-backward polarization asymmetry near the Z resonance using the OPAL detector are described. The measurements are based on analyses of tau -> e nu_e nu_tau, tau -> mu nu_mu nu_tau, tau -> pi nu_tau, tau -> rho nu_tau and tau -> a1 nu_tau decays from a sample of 144810 e+e- -> tau+ tau- candidates corresponding to an integrated luminosity of 151 pb-1. Assuming that the tau lepton decays according to V-A theory, we measure the average tau polarization near Ecm = MZ to be = (-14.10 +/- 0.73 +/- 0.55)% and the tau polarization forward-backward asymmetry to be Afb = (-10.55 +/- 0.76 +/- 0.25)%, where the first error is statistical and the second systematic. Taking into account the small effects of the photon propagator, photon-Z interference and photonic radiative corrections, these results can be expressed in terms of the lepton neutral current asymmetry parameters: Atau = 0.1456 +/- 0.0076 +/- 0.0057, Ae = 0.1454 +/- 0.0108 +/- 0.0036. These measurements ar...

  8. In-situ absolute calibration of electric-field amplitude measurements with the LPDA radio detector stations of the Pierre Auger Observatory

    CERN Document Server

    Briechle, Florian

    2016-01-01

    With the Auger Engineering Radio Array (AERA) located at the Pierre Auger Observatory, radio emission of extensive air showers is observed. To exploit the physics potential of AERA, electric-field amplitude measurements with the radio detector stations need to be well-calibrated on an absolute level. A convenient tool for far-field calibration campaigns is a flying drone. Here we make use of an octocopter to place a calibrated source at freely chosen positions above the radio detector array. Special emphasis is put on the reconstruction of the octocopter position and its accuracy during the flights. The antenna response pattern of the radio detector stations was measured in a recent calibration campaign. Results of these measurements are presented and compared to simulations. It is found that measurements and simulations are in good agreement.

  9. A technique for measurement of earth station antenna G/T by radio stars and Applications Technology Satellites.

    Science.gov (United States)

    Kochevar, H. J.

    1972-01-01

    A new technique has been developed to accurately measure the G/T of a small aperture antenna using geostationary satellites and the well established radio star method. A large aperture antenna having the capability of accurately measuring its G/T by using a radio star of known power density is used to obtain an accurate G/T to use as a reference. The CNR of both the large and small aperture antennas are then measured using an Applications Technology Satellite (ATS). After normalizing the two C/N ratios to the large antenna system noise temperature the G/T or the gain G of the small aperture antenna can then be determined.

  10. Measurements of Antenna Surface for a Millimeter-Wave Space Radio Telescope II; Metal Mesh Surface for Large Deployable Reflector

    CERN Document Server

    Kamegai, Kazuhisa

    2012-01-01

    Large deployable antennas with a mesh surface woven by fine metal wires are an important technology for communications satellites and space radio telescopes. However, it is difficult to make metal mesh surfaces with sufficient radio-frequency (RF) performance for frequencies higher than millimeter waves. In this paper, we present the RF performance of metal mesh surfaces at 43 GHz. For this purpose, we developed an apparatus to measure the reflection coefficient, transmission coefficient, and radiative coefficient of the mesh surface. The reflection coefficient increases as a function of metal mesh surface tension, whereas the radiative coefficient decreases. The anisotropic aspects of the reflection coefficient and the radiative coefficient are also clearly seen. They depend on the front and back sides of the metal mesh surface and the rotation angle. The transmission coefficient was measured to be almost constant. The measured radiative coefficients and transmission coefficients would cause significant degr...

  11. Summer Mesosphere Temperature Distribution from Wide-Angle Polarization Measurements of the Twilight Sky

    CERN Document Server

    Ugolnikov, Oleg S

    2012-01-01

    The paper contains the results of wide-angle polarization camera (WAPC) measurements of the twilight sky background conducted in summer 2011 and 2012 at 55.2 degs.N, 37.5 degs.E, southwards from Moscow. The method of single scattering separation based on polarization data is suggested. The obtained components of scattering matrixes show the domination of Rayleigh scattering in the mesosphere for all observation days. It made possible to retrieve the altitude distribution of temperature in the mesosphere. The results are compared with the temperature data by TIMED/SABER and EOS Aura/MLS instruments for nearby dates and locations.

  12. Making Ultraviolet Spectro-Polarimetry Polarization Measurements with the MSFC Solar Ultraviolet Magnetograph Sounding Rocket

    Science.gov (United States)

    West, Edward; Cirtain, Jonathan; Kobayashi, Ken; Davis, John; Gary, Allen

    2011-01-01

    This paper will describe the Marshall Space Flight Center's Solar Ultraviolet Magnetograph Investigation (SUMI) sounding rocket program. This paper will concentrate on SUMI's VUV optics, and discuss their spectral, spatial and polarization characteristics. While SUMI's first flight (7/30/2010) met all of its mission success criteria, there are several areas that will be improved for its second and third flights. This paper will emphasize the MgII linear polarization measurements and describe the changes that will be made to the sounding rocket and how those changes will improve the scientific data acquired by SUMI.

  13. Spin transport at the international linear collider and its impact on the measurement of polarization

    Energy Technology Data Exchange (ETDEWEB)

    Beckmann, Moritz

    2013-12-15

    At the planned International Linear Collider (ILC), the longitudinal beam polarization needs to be determined with an unprecedented precision. For that purpose, the beam delivery systems (BDS) are equipped with two laser Compton polarimeters each, which are foreseen to achieve a systematic uncertainty of {<=} 0.25 %. The polarimeters are located 1.6 km upstream and 150 m downstream of the e{sup +}e{sup -} interaction point (IP). The average luminosity-weighted longitudinal polarization P{sup lumi}{sub z}, which is the decisive quantity for the experiments, has to be determined from these measurements with the best possible precision. Therefore, a detailed understanding of the spin transport in the BDS is mandatory to estimate how precise the longitudinal polarization at the IP is known from the polarimeter measurements. The envisaged precision for the propagation of the measurement value is {<=} 0.1 %. This thesis scrutinizes the spin transport in view of the achievable precision. A detailed beamline simulation for the BDS has been developed, including the simulation of the beam-beam collisions at the IP. The following factors which might limit the achievable precision is investigated: a variation of the beam parameters, the beam alignment precision at the polarimeters and the IP, the bunch rotation at the IP, the detector magnets, the beam-beam collisions, the emission of synchrotron radiation and misalignments of the beamline elements. In absence of collisions, a precision of 0.085% on the propagation of the measured longitudinal polarization has been found achievable. This result however depends mainly on the presumed precisions for the parallel alignment of the beam at the polarimeters and for the alignment of polarization vector. In presence of collisions, the measurement at the downstream polarimeter depends strongly on the intensity of the collision and the size of the polarimeter laser spot. Therefore, a more detailed study of the laser-bunch interaction is

  14. Run05 Proton Beam Polarization Measurements by pC-Polarimeter (ver. 1.1)

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawa,I.; Alekseev, I.; Bazilevsky, A.; Bravar, A.; Bunce, G.; Dhawan, S.; Eyser, K.O.; Gill, R.; Haeberli, W.; Huang, H.; Makdisi, Y.; Nass, A.; Okada, H.; Stephenson, E.; Svirida, D.N.; Wise, T.; Wood, J.; Yip, K.; Zelenski, A.

    2008-07-01

    The polarization of the proton beams [1, 2] at the Relativistic Heavy Ion Collider (RHIC)[3] RHIC ring. The H-Jet polarimeter is located at the collision point allowing measurements of absolute normalization is provided by the hydrogen polarimeter, which measures over 1 {approx} 2 another measurement rather than measuring the absolute polarization. both beams. Two identical pC-polarimeters are equipped in the yellow and blue rings, where carbon ribbon target, providing fast feedback to beam operations and experiments. The days to obtain {approx} 5% statistical uncertainty (in Run05). Thus, the operation of the carbon is measured using both an atomic beam source hydrogen gas jet (H-Jet)[4, 5] and proton-carbon polarimeters was focused on better control of relative stability between one measurement to statistical accuracy within 20 to 30 seconds using an ultra-thin (typically 6 {approx} 8 {micro}g/cm{sup 2}) the rings are separated. The pC-polarimeter measures relative polarization to a few percent.

  15. Measurement of Lambda polarization in muon neutrino charged current interactions in NOMAD

    CERN Document Server

    Naumov, Dmitry V.

    2000-01-01

    The Lambda polarization in muon neutrino charged current interactions has been measured in the NOMAD experiment. We observe negative polarization along the W - boson direction which is enhanced in the target fragmentation region: Px (xF 0) = -0.09 +/- 0.06(stat) +/- 0.03(sys). These results provide a test of different models describing the nucleon spin composition and the spin transfer mechanisms. A significant transverse polarization (in the direction orthogonal to the Lambda production plane) has been observed for the first time in a neutrino experiment: Py = -0.22 +/- 0.03(stat) +/- 0.01(sys). The dependence of the absolute value of Py on the Lambda transverse momentum with respect to the hadronic jet direction is in qualitative agreement with the results from unpolarized hadron-hadron experiments.

  16. Correlated electric field and low-energy electron measurements in the low-altitude polar cusp

    Science.gov (United States)

    Kintner, P. M.; Ackerson, K. L.; Gurnett, D. A.; Frank, L. A.

    1978-01-01

    Correlated electric field and low-energy electron measurements are presented for two passes of Hawkeye 1 through the south polar cusp at 2000-km altitude during local morning. In one case the electric field reversal coincides with the boundary of detectable 5.2keV electron intensities and the equatorward boundary of the cusp. In the other case the electric field reversal and the 5.2 keV electron trapping boundary coincide, but the equatorward edge of the cusp as determined from the presence of 180 eV electron intensities is 5 degrees invariant latitude equatorward of the electric field reversal. It is concluded that in the second case, electron intensities associated with the polar cusp populate closed dayside field lines, and hence the corresponding equatorward edge of these electron intensities is not always an indicator of the boundary between closed dayside field lines and polar cap field lines.

  17. A Technique for Measuring Microparticles in Polar Ice Using Micro-Raman Spectroscopy

    Directory of Open Access Journals (Sweden)

    Toshimitsu Sakurai

    2010-01-01

    Full Text Available We describe in detail our method of measuring the chemical forms of microparticles in polar ice samples through micro-Raman spectroscopy. The method is intended for solid ice samples, an important point because melting the ice can result in dissociation, contamination, and chemical reactions prior to or during a measurement. We demonstrate the technique of measuring the chemical forms of these microparticles and show that the reference spectra of those salts expected to be common in polar ice are unambiguously detected. From our measurements, Raman intensity of sulfate salts is relatively higher than insoluble dust due to the specific Raman scattering cross-section of chemical forms of microparticles in ice.

  18. Measurement of the Induced Polarization of Lambda (1116) in Kaon Electroproduction with CLAS

    Energy Technology Data Exchange (ETDEWEB)

    Marianna Gabrielyan, Brian Raue, Seema Dhamija, Daniel S. Carman

    2010-08-01

    The CLAS Collaboration is using the p(e,e[prime]K+p)pi- reaction to measure the induced polarization of the electroproduced Lambda(1116). In this experiment a 5.499-GeV electron beam was incident upon an unpolarized liquid-hydrogen target. The CEBAF Large Acceptance Spectrometer (CLAS) was used to detect the scattered electron, the kaon, and the decay proton from the Lambda hyperon. CLAS allowed for a large kinematic acceptance in Q2(0.75<=Q2<=3.5 GeV2) and W(1.6<=W<=3.0 GeV), as well as the kaon center-of-mass scattering angle. The goal is to map out the kinematic dependencies for the induced polarization in order to provide new constraints on models of K-hyperon production. Along with previously published photo- and electroproduction cross sections and polarization observables from CLAS, LEPS, SAPHIR, and GRAAL, these new induced polarization data are needed in coupled-channel analyses to search for previously unobserved s-channel resonances. Preliminary polarization results are presented.

  19. Research on polarization state of prism coupler sensor for measuring liquid refractive index

    Science.gov (United States)

    Zhang, Zhi-Wei

    2013-09-01

    Due to many experimental data required and a lot of calculations involved, it is very complex and cumbersome to model prism-based liquid-refractive-index-measuring methods. By use of the feature of TE-polarized wave and TM-polarized wave and differential measurement principle, we developed a new method of mathematical modeling for measuring refractive index of a liquid based upon Fresnel formula and prism internal reflection at incident angle less than critical angle. With this method only two different concentrations measurements for a kind of solution can lead to the determination of computational model. It introduces the principle of an optic-fiber sensor system based on prism-coupler for measuring refractive index of a liquid, and it contains the configuration picture of the sensing optical path, the spectrogram of the semiconductor laser and the structure block diagram of measuring system, the system is mainly made up of the semiconductor laser with 1654.14nm in wavelength, 1×2 optical switch, Y-shaped photo-coupler with coupled rate 50:50, the detector based on isosceles prism-coupler, the data process and control system based on AT89C51 and photoelectric transformer. For TM-polarized wave and TE-polarized wave, theoretical simulations show that the ratio of sensitivity is 1.11, therefore, the beam that the component of TM-polarized wave is more than the one of TE-polarized wave is advantageous to heightening the systemۥs measurement sensitivity. Measurements are performed to examine the validity of the theoretical model and four theoretical models are given, and these results indicate the feasibility of four theoretical models with an error of 3%. In this study, a beam of light is broken down into two beams in the coupler of Y-shaped coupler, the one acts as the reference optical path, the other is known as the sensing optical path, consequently the method can limit well the fluctuation of the light source, the variation of the photodiodeۥ s dark

  20. Measurement of the cosmic microwave background polarization lensing power spectrum with the POLARBEAR experiment.

    Science.gov (United States)

    Ade, P A R; Akiba, Y; Anthony, A E; Arnold, K; Atlas, M; Barron, D; Boettger, D; Borrill, J; Chapman, S; Chinone, Y; Dobbs, M; Elleflot, T; Errard, J; Fabbian, G; Feng, C; Flanigan, D; Gilbert, A; Grainger, W; Halverson, N W; Hasegawa, M; Hattori, K; Hazumi, M; Holzapfel, W L; Hori, Y; Howard, J; Hyland, P; Inoue, Y; Jaehnig, G C; Jaffe, A; Keating, B; Kermish, Z; Keskitalo, R; Kisner, T; Le Jeune, M; Lee, A T; Linder, E; Leitch, E M; Lungu, M; Matsuda, F; Matsumura, T; Meng, X; Miller, N J; Morii, H; Moyerman, S; Myers, M J; Navaroli, M; Nishino, H; Paar, H; Peloton, J; Quealy, E; Rebeiz, G; Reichardt, C L; Richards, P L; Ross, C; Schanning, I; Schenck, D E; Sherwin, B; Shimizu, A; Shimmin, C; Shimon, M; Siritanasak, P; Smecher, G; Spieler, H; Stebor, N; Steinbach, B; Stompor, R; Suzuki, A; Takakura, S; Tomaru, T; Wilson, B; Yadav, A; Zahn, O

    2014-07-11

    Gravitational lensing due to the large-scale distribution of matter in the cosmos distorts the primordial cosmic microwave background (CMB) and thereby induces new, small-scale B-mode polarization. This signal carries detailed information about the distribution of all the gravitating matter between the observer and CMB last scattering surface. We report the first direct evidence for polarization lensing based on purely CMB information, from using the four-point correlations of even- and odd-parity E- and B-mode polarization mapped over ∼30 square degrees of the sky measured by the POLARBEAR experiment. These data were analyzed using a blind analysis framework and checked for spurious systematic contamination using null tests and simulations. Evidence for the signal of polarization lensing and lensing B modes is found at 4.2σ (stat+sys) significance. The amplitude of matter fluctuations is measured with a precision of 27%, and is found to be consistent with the Lambda cold dark matter cosmological model. This measurement demonstrates a new technique, capable of mapping all gravitating matter in the Universe, sensitive to the sum of neutrino masses, and essential for cleaning the lensing B-mode signal in searches for primordial gravitational waves.

  1. Spectrally resolved fluorescence lifetime imaging of Nile red for measurements of intracellular polarity

    Science.gov (United States)

    Levitt, James A.; Chung, Pei-Hua; Suhling, Klaus

    2015-09-01

    Spectrally resolved confocal microscopy and fluorescence lifetime imaging have been used to measure the polarity of lipid-rich regions in living HeLa cells stained with Nile red. The emission peak from the solvatochromic dye in lipid droplets is at a shorter wavelength than other, more polar, stained internal membranes, and this is indicative of a low polarity environment. We estimate that the dielectric constant, ɛ, is around 5 in lipid droplets and 25<ɛ<40 in other lipid-rich regions. Our spectrally resolved fluorescence lifetime imaging microscopy (FLIM) data show that intracellular Nile red exhibits complex, multiexponential fluorescence decays due to emission from a short lifetime locally excited state and a longer lifetime intramolecular charge transfer state. We measure an increase in the average fluorescence lifetime of the dye with increasing emission wavelength, as shown using phasor plots of the FLIM data. We also show using these phasor plots that the shortest lifetime decay components arise from lipid droplets. Thus, fluorescence lifetime is a viable contrast parameter for distinguishing lipid droplets from other stained lipid-rich regions. Finally, we discuss the FLIM of Nile red as a method for simultaneously mapping both polarity and relative viscosity based on fluorescence lifetime measurements.

  2. Measurement of the photon polarization using ${B_s^0\\to \\phi\\gamma}$ at LHCb.

    CERN Document Server

    Hoballah, Mostafa; Deschamps, Olivier

    This thesis is dedicated to the study of the photon polarization in ${B_s^0\\to \\phi\\gamma}$ decays at LHCb. At the quark level, such decays proceed via a $b \\to s \\gamma$ penguin transition and are sensitive to possible virtual contributions from New Physics. The measurement of the photon polarization stands also as a test of the $V-A$ structure of the Standard Model coupling in the processes mediated by loop penguin diagrams. The measurement of the photon polarization can be done through a study of the time-dependent decay rate of the $B$ meson. A delicate treatment has been done to understand the proper time distribution and the selection acceptance affecting it. To control the proper time acceptance, data driven control methods have been developed. Several possible strategies to measure the photon polarization are introduced and preliminary blinded results are presented. A study of some of the systematic effects is discussed. In the context of studying radiative decays, the author has developed a new photo...

  3. Degree of circular polarization of soft X-rays emitted from a multi-polarization-mode undulator characterized by means of magnetic circular dichroism measurements.

    Science.gov (United States)

    Oura, Masaki; Nakamura, Tetsuya; Takeuchi, Tomoyuki; Senba, Yasunori; Ohashi, Haruhiko; Shirasawa, Katsutoshi; Tanaka, Takashi; Takeuchi, Masao; Furukawa, Yukito; Hirono, Toko; Ohata, Toru; Kitamura, Hideo; Shin, Shik

    2007-11-01

    The degree of circular polarization of soft X-rays emitted from the multi-polarization-mode undulator of BL17SU at SPring-8 has been deduced by means of magnetic circular dichroism in core-level X-ray absorption spectroscopy for a ferrimagnetic Gd-Fe-Co amorphous thin film. The results of reference measurements performed using well characterized undulator radiation of BL25SU at SPring-8 have also been utilized. The degrees of circular polarization were presumed for all the available operational modes and were compared with simple theoretical calculations. It was found that the calculated degrees of circular polarization were validated by the measurements reasonably well and will be useful in further experiments at BL17SU.

  4. Vectorial Radio Interferometry with LOPES 3D

    CERN Document Server

    Huber, D; Arteaga, J C; Bähren, L; Bekk, K; Bertaina, M; Biermann, P L; Blümer, J; Bozdog, H; Brancus, I M; Chiavassa, A; Daumiller, K; de Souza, V; Di Pierro, F; Doll, P; Engel, R; Falcke, H; Fuchs, B; Fuhrmann, D; Gemmeke, H; Grupen, C; Haungs, A; Heck, D; Hörandel, J R; Horneffer, A; Huege, T; Isar, P G; Kampert, K H; Kang, D; Krömer, O; Kuijpers, J; Link, K; Łuczak, P; Ludwig, M; Mathes, H J; Melissas, M; Morello, C; Oehlschläger, J; Palmieri, N; Pierog, T; Rautenberg, J; Rebel, H; Roth, M; Rühle, C; Saftoiu, A; Schieler, H; Schmid, A; Schröder, F G; Sima, O; Toma, G; Trinchero, G C; Weindl, A; Wochele, J; Wommer, M; Zabierowski, J; Zensus, J A

    2013-01-01

    One successful detection technique for high-energy cosmic rays is based on the radio signal emitted by the charged particles in an air shower. The LOPES experiment at Karlsruhe Institute of Technology, Germany, has made major contributions to the evolution of this technique. LOPES was reconfigured several times to improve and further develop the radio detection technique. In the latest setup LOPES consisted of 10 tripole antennas. With this, LOPES 3D was the first cosmic ray experiment measuring all three vectorial field components at once and thereby gaining the full information about the electric field vector. We present an analysis based on the data taken with special focus on the benefits of a direct measurement of the vertical polarization component. We demonstrate that by measuring all polarization components the detection and reconstruction efficiency is increased and noisy single channel data can be reconstructed by utilising the information from the other two channels of one antenna station.

  5. Realization of Bipartite Positive-Operator-Value Measurements of Two-Photon Polarization States

    Institute of Scientific and Technical Information of China (English)

    LIN Qing

    2009-01-01

    In this letter, we propose a scheme of a special quantum optical Fredkin gate assisted by optical manip-ulations and postselection from the coincidence measurements, and then modify it with cross-Kerr nonlinearities to be suitable for the realization of all possible positive operator-valued measurements of bipartite polarization states.This scheme is feasible in the lab with the current experimental technology.

  6. Investigation of the radio wavefront of air showers with LOPES measurements and CoREAS simulations (ARENA 2014)

    CERN Document Server

    Schröder, F G; Arteaga-Velazquez, J C; Bähren, L; Bekk, K; Bertaina, M; Biermann, P L; Blümer, J; Bozdog, H; Brancus, I M; Cantoni, E; Chiavassa, A; Daumiller, K; de Souza, V; Di Pierro, F; Doll, P; Engel, R; Falcke, H; Fuchs, B; Fuhrmann, D; Gemmeke, H; Grupen, C; Haungs, A; Heck, D; Hörandel, J R; Horneffer, A; Huber, D; Huege, T; Isar, P G; Kampert, K -H; Kang, D; Krömer, O; Kuijpers, J; Link, K; Luczak, P; Ludwig, M; Mathes, H J; Melissas, M; Morello, C; Oehlschläger, J; Palmieri, N; Pierog, T; Rautenberg, J; Rebel, H; Roth, M; Rühle, C; Saftoiu, A; Schieler, H; Schmidt, A; Schoo, S; Sima, O; Toma, G; Trinchero, G C; Weindl, A; Wochele, J; Zabierowski, J; Zensus, J A

    2015-01-01

    We investigated the radio wavefront of cosmic-ray air showers with LOPES measurements and CoREAS simulations: the wavefront is of approximately hyperbolic shape and its steepness is sensitive to the shower maximum. For this study we used 316 events with an energy above 0.1 EeV and zenith angles below $45^\\circ$ measured by the LOPES experiment. LOPES was a digital radio interferometer consisting of up to 30 antennas on an area of approximately 200 m x 200 m at an altitude of 110 m above sea level. Triggered by KASCADE-Grande, LOPES measured the radio emission between 43 and 74 MHz, and our analysis might strictly hold only for such conditions. Moreover, we used CoREAS simulations made for each event, which show much clearer results than the measurements suffering from high background. A detailed description of our result is available in our recent paper published in JCAP09(2014)025. The present proceeding contains a summary and focuses on some additional aspects, e.g., the asymmetry of the wavefront: Accordin...

  7. Measurement of longitudinal spin asymmetries for weak boson production in polarized proton-proton collisions at RHIC.

    Science.gov (United States)

    Adamczyk, L; Adkins, J K; Agakishiev, G; Aggarwal, M M; Ahammed, Z; Alekseev, I; Alford, J; Anson, C D; Aparin, A; Arkhipkin, D; Aschenauer, E C; Averichev, G S; Balewski, J; Banerjee, A; Beavis, D R; Bellwied, R; Bhasin, A; Bhati, A K; Bhattarai, P; Bichsel, H; Bielcik, J; Bielcikova, J; Bland, L C; Bordyuzhin, I G; Borowski, W; Bouchet, J; Brandin, A V; Brovko, S G; Bültmann, S; Bunzarov, I; Burton, T P; Butterworth, J; Caines, H; Calderón de la Barca Sánchez, M; Campbell, J M; Cebra, D; Cendejas, R; Cervantes, M C; Chaloupka, P; Chang, Z; Chattopadhyay, S; Chen, H F; Chen, J H; Chen, L; Cheng, J; Cherney, M; Chikanian, A; Christie, W; Chwastowski, J; Codrington, M J M; Contin, G; Cramer, J G; Crawford, H J; Cui, X; Das, S; Davila Leyva, A; De Silva, L C; Debbe, R R; Dedovich, T G; Deng, J; Derevschikov, A A; Derradi de Souza, R; Dhamija, S; di Ruzza, B; Didenko, L; Dilks, C; Ding, F; Djawotho, P; Dong, X; Drachenberg, J L; Draper, J E; Du, C M; Dunkelberger, L E; Dunlop, J C; Efimov, L G; Engelage, J; Engle, K S; Eppley, G; Eun, L; Evdokimov, O; Eyser, O; Fatemi, R; Fazio, S; Fedorisin, J; Filip, P; Finch, E; Fisyak, Y; Flores, C E; Gagliardi, C A; Gangadharan, D R; Garand, D; Geurts, F; Gibson, A; Girard, M; Gliske, S; Greiner, L; Grosnick, D; Gunarathne, D S; Guo, Y; Gupta, A; Gupta, S; Guryn, W; Haag, B; Hamed, A; Han, L-X; Haque, R; Harris, J W; Heppelmann, S; Hirsch, A; Hoffmann, G W; Hofman, D J; Horvat, S; Huang, B; Huang, H Z; Huang, X; Huck, P; Humanic, T J; Igo, G; Jacobs, W W; Jang, H; Judd, E G; Kabana, S; Kalinkin, D; Kang, K; Kauder, K; Ke, H W; Keane, D; Kechechyan, A; Kesich, A; Khan, Z H; Kikola, D P; Kisel, I; Kisiel, A; Koetke, D D; Kollegger, T; Konzer, J; Koralt, I; Kosarzewski, L K; Kotchenda, L; Kraishan, A F; Kravtsov, P; Krueger, K; Kulakov, I; Kumar, L; Kycia, R A; Lamont, M A C; Landgraf, J M; Landry, K D; Lauret, J; Lebedev, A; Lednicky, R; Lee, J H; LeVine, M J; Li, C; Li, W; Li, X; Li, X; Li, Y; Li, Z M; Lisa, M A; Liu, F; Ljubicic, T; Llope, W J; Lomnitz, M; Longacre, R S; Luo, X; Ma, G L; Ma, Y G; Madagodagettige Don, D M M D; Mahapatra, D P; Majka, R; Margetis, S; Markert, C; Masui, H; Matis, H S; McDonald, D; McShane, T S; Minaev, N G; Mioduszewski, S; Mohanty, B; Mondal, M M; Morozov, D A; Mustafa, M K; Nandi, B K; Nasim, Md; Nayak, T K; Nelson, J M; Nigmatkulov, G; Nogach, L V; Noh, S Y; Novak, J; Nurushev, S B; Odyniec, G; Ogawa, A; Oh, K; Ohlson, A; Okorokov, V; Oldag, E W; Olvitt, D L; Pachr, M; Page, B S; Pal, S K; Pan, Y X; Pandit, Y; Panebratsev, Y; Pawlak, T; Pawlik, B; Pei, H; Perkins, C; Peryt, W; Pile, P; Planinic, M; Pluta, J; Poljak, N; Poniatowska, K; Porter, J; Poskanzer, A M; Pruthi, N K; Przybycien, M; Pujahari, P R; Putschke, J; Qiu, H; Quintero, A; Ramachandran, S; Raniwala, R; Raniwala, S; Ray, R L; Riley, C K; Ritter, H G; Roberts, J B; Rogachevskiy, O V; Romero, J L; Ross, J F; Roy, A; Ruan, L; Rusnak, J; Rusnakova, O; Sahoo, N R; Sahu, P K; Sakrejda, I; Salur, S; Sandweiss, J; Sangaline, E; Sarkar, A; Schambach, J; Scharenberg, R P; Schmah, A M; Schmidke, W B; Schmitz, N; Seger, J; Seyboth, P; Shah, N; Shahaliev, E; Shanmuganathan, P V; Shao, M; Sharma, B; Shen, W Q; Shi, S S; Shou, Q Y; Sichtermann, E P; Singaraju, R N; Skoby, M J; Smirnov, D; Smirnov, N; Solanki, D; Sorensen, P; Spinka, H M; Srivastava, B; Stanislaus, T D S; Stevens, J R; Stock, R; Strikhanov, M; Stringfellow, B; Sumbera, M; Sun, X; Sun, X M; Sun, Y; Sun, Z; Surrow, B; Svirida, D N; Symons, T J M; Szelezniak, M A; Takahashi, J; Tang, A H; Tang, Z; Tarnowsky, T; Thomas, J H; Timmins, A R; Tlusty, D; Tokarev, M; Trentalange, S; Tribble, R E; Tribedy, P; Trzeciak, B A; Tsai, O D; Turnau, J; Ullrich, T; Underwood, D G; Van Buren, G; van Nieuwenhuizen, G; Vandenbroucke, M; Vanfossen, J A; Varma, R; Vasconcelos, G M S; Vasiliev, A N; Vertesi, R; Videbæk, F; Viyogi, Y P; Vokal, S; Vossen, A; Wada, M; Wang, F; Wang, G; Wang, H; Wang, J S; Wang, X L; Wang, Y; Wang, Y; Webb, G; Webb, J C; Westfall, G D; Wieman, H; Wissink, S W; Witt, R; Wu, Y F; Xiao, Z; Xie, W; Xin, K; Xu, H; Xu, J; Xu, N; Xu, Q H; Xu, Y; Xu, Z; Yan, W; Yang, C; Yang, Y; Yang, Y; Ye, Z; Yepes, P; Yi, L; Yip, K; Yoo, I-K; Yu, N; Zawisza, Y; Zbroszczyk, H; Zha, W; Zhang, J B; Zhang, J L; Zhang, S; Zhang, X P; Zhang, Y; Zhang, Z P; Zhao, F; Zhao, J; Zhong, C; Zhu, X; Zhu, Y H; Zoulkarneeva, Y; Zyzak, M

    2014-08-15

    We report measurements of single- and double-spin asymmetries for W^{±} and Z/γ^{*} boson production in longitudinally polarized p+p collisions at sqrt[s]=510  GeV by the STAR experiment at RHIC. The asymmetries for W^{±} were measured as a function of the decay lepton pseudorapidity, which provides a theoretically clean probe of the proton's polarized quark distributions at the scale of the W mass. The results are compared to theoretical predictions, constrained by polarized deep inelastic scattering measurements, and show a preference for a sizable, positive up antiquark polarization in the range 0.05

  8. Measurement of longitudinal spin asymmetries for weak boson production in polarized proton-proton collisions at RHIC

    CERN Document Server

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