WorldWideScience

Sample records for proposed gamma polarization

  1. The Gamma Factory proposal for CERN

    CERN Document Server

    Krasny, Mieczyslaw Witold

    2015-01-01

    This year, 2015, marks the centenary of the publication of Einsteins Theory of General Relativity and it has been named the International Year of Light and light-based technologies by the UN General Assembly. It is thus timely to discuss the possibility of broadening the present CERN research program by including a new component based on a novel concept of the light source which could pave a way towards a multipurpose Gamma Factory. The proposed light source could be realized at CERN by using the infrastructure of the existing accelerators. It could push the intensity limits of the presently operating light-sources by at least 7 orders of magnitude, reaching the flux of the order of 10^17 photons/s, in the particularly interesting gamma-ray energy domain of 1 < Ephoton < 400 MeV. This domain is out of reach for the FEL-based light sources. The energy-tuned, quasi-monochromatic gamma beams, together with the gamma-beam-driven, high intensity secondary beams of polarized positrons, polarized muons, neutro...

  2. Sensitivity of Gamma-Ray Detectors to Polarization

    OpenAIRE

    Yadigaroglu, I. -A.

    1996-01-01

    Previous studies have shown that the largest gamma-ray detector to date, EGRET, does not have useful polarization sensitivity. We have explored here some improved approaches to analyzing gamma-ray pair production events, leading to important gains in sensitivity to polarization. The performance of the next generation gamma-ray instrument GLAST is investigated using a detailed Monte Carlo simulation of the complete detector.

  3. Early optical polarization of a gamma-ray burst afterglow.

    Science.gov (United States)

    Mundell, Carole G; Steele, Iain A; Smith, Robert J; Kobayashi, Shiho; Melandri, Andrea; Guidorzi, Cristiano; Gomboc, Andreja; Mottram, Chris J; Clarke, David; Monfardini, Alessandro; Carter, David; Bersier, David

    2007-03-30

    We report the optical polarization of a gamma-ray burst (GRB) afterglow, obtained 203 seconds after the initial burst of gamma-rays from GRB 060418, using a ring polarimeter on the robotic Liverpool Telescope. Our robust (2sigma) upper limit on the percentage of polarization, less than 8%, coincides with the fireball deceleration time at the onset of the afterglow. The combination of the rate of decay of the optical brightness and the low polarization at this critical time constrains standard models of GRB ejecta, ruling out the presence of a large-scale ordered magnetic field in the emitting region.

  4. Performance study of the gamma-ray bursts polarimeter POLAR

    Science.gov (United States)

    Sun, J. C.; Wu, B. B.; Bao, T. W.; Batsch, T.; Bernasconi, T.; Britvitch, I.; Cadoux, F.; Cernuda, I.; Chai, J. Y.; Dong, Y. W.; Gauvin, N.; Hajdas, W.; He, J. J.; Kole, M.; Kong, M. N.; Kong, S. W.; Lechanoine-Leluc, C.; Li, Lu; Liu, J. T.; Liu, X.; Marcinkowski, R.; Orsi, S.; Pohl, M.; Produit, N.; Rapin, D.; Rutczynska, A.; Rybka, D.; Shi, H. L.; Song, L. M.; Szabelski, J.; Wang, R. J.; Wen, X.; Xiao, H. L.; Xiong, S. L.; Xu, H. H.; Xu, M.; Zhang, L.; Zhang, L. Y.; Zhang, S. N.; Zhang, X. F.; Zhang, Y. J.; Zwolinska, A.

    2016-07-01

    The Gamma-ray Burst Polarimeter-POLAR is a highly sensitive detector which is dedicated to the measurement of GRB's polarization with a large effective detection area and a large field of view (FOV). The optimized performance of POLAR will contribute to the capture and measurement of the transient sources like GRBs and Solar Flares. The detection energy range of POLAR is 50 keV 500 keV, and mainly dominated by the Compton scattering effect. POLAR consists of 25 detector modular units (DMUs), and each DMU is composed of low Z material Plastic Scintillators (PS), multi-anode photomultipliers (MAPMT) and multi-channel ASIC Front-end Electronics (FEE). POLAR experiment is an international collaboration project involving China, Switzerland and Poland, and is expected to be launched in September in 2016 onboard the Chinese space laboratory "Tiangong-2 (TG-2)". With the efforts from the collaborations, POLAR has experienced the Demonstration Model (DM) phase, Engineering and Qualification Model (EQM) phase, Qualification Model (QM) phase, and now a full Flight Model (FM) of POLAR has been constructed. The FM of POLAR has passed the environmental acceptance tests (thermal cycling, vibration, shock and thermal vacuum tests) and experienced the calibration tests with both radioactive sources and 100% polarized Gamma-Ray beam at ESRF after its construction. The design of POLAR, Monte-Carlo simulation analysis, as well as the performance test results will all be introduced in this paper.

  5. MAGNETIC STRUCTURES IN GAMMA-RAY BURST JETS PROBED BY GAMMA-RAY POLARIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Yonetoku, Daisuke; Murakami, Toshio; Morihara, Yoshiyuki; Takahashi, Takuya; Wakashima, Yudai; Yonemochi, Hajime; Sakashita, Tomonori; Fujimoto, Hirofumi; Kodama, Yoshiki [College of Science and Engineering, School of Mathematics and Physics, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192 (Japan); Gunji, Shuichi; Toukairin, Noriyuki [Department of Physics, Faculty of Science, Yamagata University, 1-4-12, Koshirakawa, Yamagata, Yamagata 990-8560 (Japan); Mihara, Tatehiro [Cosmic Radiation Laboratory, RIKEN, 2-1, Hirosawa, Wako City, Saitama 351-0198 (Japan); Toma, Kenji, E-mail: yonetoku@astro.s.kanazawa-u.ac.jp [Department of Earth and Space Science, Osaka University, Toyonaka 560-0043 (Japan)

    2012-10-10

    We report polarization measurements in two prompt emissions of gamma-ray bursts, GRB 110301A and GRB 110721A, observed with the gamma-ray burst polarimeter (GAP) on borad the IKAROS solar sail mission. We detected linear polarization signals from each burst with polarization degree of {Pi} = 70 {+-} 22% with statistical significance of 3.7{sigma} for GRB 110301A, and {Pi} = 84{sup +16}{sub -28}% with 3.3{sigma} confidence level for GRB 110721A. We did not detect any significant change of polarization angle. These two events had shorter durations and dimmer brightness compared with GRB 100826A, which showed a significant change of polarization angle, as reported in Yonetoku et al. Synchrotron emission model can be consistent with the data of the three GRBs, while the photospheric quasi-thermal emission model is not favored. We suggest that magnetic field structures in the emission region are globally ordered fields advected from the central engine.

  6. Polarized Emission from Gamma-Ray Burst Jets

    Directory of Open Access Journals (Sweden)

    Shiho Kobayashi

    2017-11-01

    Full Text Available I review how polarization signals have been discussed in the research field of Gamma-Ray Bursts (GRBs. I mainly discuss two subjects in which polarimetry enables us to study the nature of relativistic jets. (1 Jet breaks: Gamma-ray bursts are produced in ultra-relativistic jets. Due to the relativistic beaming effect, the emission can be modeled in a spherical model at early times. However, as the jet gradually slows down, we begin to see the edge of the jet together with polarized signals at some point. (2 Optical flash: later time afterglow is known to be insensitive to the properties of the original ejecta from the GRB central engine. However, a short-lived, reverse shock emission would enable us to study the nature of of GRB jets. I also briefly discuss the recent detection of optical circular polarization in GRB afterglow.

  7. Evolution of the polarization of the optical afterglow of the gamma-ray burst GRB030329.

    Science.gov (United States)

    Greiner, Jochen; Klose, Sylvio; Reinsch, Klaus; Schmid, Hans Martin; Sari, Re'em; Hartmann, Dieter H; Kouveliotou, Chryssa; Rau, Arne; Palazzi, Eliana; Straubmeier, Christian; Stecklum, Bringfried; Zharikov, Sergej; Tovmassian, Gaghik; Bärnbantner, Otto; Ries, Christoph; Jehin, Emmanuel; Henden, Arne; Kaas, Anlaug A; Grav, Tommy; Hjorth, Jens; Pedersen, Holger; Wijers, Ralph A M J; Kaufer, Andreas; Park, Hye-Sook; Williams, Grant; Reimer, Olaf

    2003-11-13

    The association of a supernova with GRB030329 strongly supports the 'collapsar' model of gamma-ray bursts, where a relativistic jet forms after the progenitor star collapses. Such jets cannot be spatially resolved because gamma-ray bursts lie at cosmological distances; their existence is instead inferred from 'breaks' in the light curves of the afterglows, and from the theoretical desire to reduce the estimated total energy of the burst by proposing that most of it comes out in narrow beams. Temporal evolution of the polarization of the afterglows may provide independent evidence for the jet structure of the relativistic outflow. Small-level polarization ( approximately 1-3 per cent) has been reported for a few bursts, but its temporal evolution has yet to be established. Here we report polarimetric observations of the afterglow of GRB030329. We establish the polarization light curve, detect sustained polarization at the per cent level, and find significant variability. The data imply that the afterglow magnetic field has a small coherence length and is mostly random, probably generated by turbulence, in contrast with the picture arising from the high polarization detected in the prompt gamma-rays from GRB021206 (ref. 18).

  8. SYSTEMATIC STUDY OF GAMMA-RAY-BRIGHT BLAZARS WITH OPTICAL POLARIZATION AND GAMMA-RAY VARIABILITY

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Ryosuke; Fukazawa, Yasushi; Kanda, Yuka; Shiki, Kensei; Kawabata, Miho; Nakaoka, Tatsuya; Takaki, Katsutoshi; Takata, Koji; Ui, Takahiro [Department of Physical Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Nalewajko, Krzysztof; Madejski, Greg M. [Kavli Institute for Particle Astrophysics and Cosmology, SLAC National Accelerator Laboratory, Stanford University, 2575 Sand Hill Road M/S 29, Menlo Park, CA 94025 (United States); Uemura, Makoto; Tanaka, Yasuyuki T.; Kawabata, Koji S.; Akitaya, Hiroshi; Ohsugi, Takashi [Hiroshima Astrophysical Science Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Schinzel, Frank K. [Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131 (United States); Moritani, Yuki [Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes for Advanced Study, The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Sasada, Mahito [Institute for Astrophysical Research, Boston University, 725 Commonwealth Avenue, Boston, MA 02215 (United States); Yamanaka, Masayuki, E-mail: itoh@hep01.hepl.hiroshima-u.ac.jp, E-mail: itoh@hp.phys.titech.ac.jp [Department of Physics, Faculty of Science and Engineering, Konan University, Okamoto, Kobe, Hyogo 658-8501 (Japan); and others

    2016-12-10

    Blazars are highly variable active galactic nuclei that emit radiation at all wavelengths from radio to gamma rays. Polarized radiation from blazars is one key piece of evidence for synchrotron radiation at low energies, and it also varies dramatically. The polarization of blazars is of interest for understanding the origin, confinement, and propagation of jets. However, even though numerous measurements have been performed, the mechanisms behind jet creation, composition, and variability are still debated. We performed simultaneous gamma-ray and optical photopolarimetry observations of 45 blazars between 2008 July and 2014 December to investigate the mechanisms of variability and search for a basic relation between the several subclasses of blazars. We identify a correlation between the maximum degree of optical linear polarization and the gamma-ray luminosity or the ratio of gamma-ray to optical fluxes. Since the maximum polarization degree depends on the condition of the magnetic field (chaotic or ordered), this result implies a systematic difference in the intrinsic alignment of magnetic fields in parsec-scale relativistic jets between different types of blazars (flat-spectrum radio quasars vs. BL Lacs) and consequently between different types of radio galaxies (FR I versus FR II).

  9. A polarized look at nucleons: Laser electron gamma source

    International Nuclear Information System (INIS)

    1991-01-01

    As the title suggests we are going to look at reactions induced on nucleons by polarized photons. The results I am going to show today are from the Laser Electron Gamma Source, or ''LEGS'' facility, at Brookhaven National Laboratory. At LEGS, gamma ray beams are produced by backscattering laser light from relativistic electrons. I will only summarize the main characteristics of this facility, and leave an in depth description to Dr. Schaerf who will discuss LEGS and other similar backscattering facilities on Wednesday. Reactions with polarized photons inevitably reflect interference terms that for the most part remain hidden in spin-averaged unpolarized measurements. This provides a tool for probing interactions that depend upon spin. In particular, we are going to look today at two cases where the polarization is used to probe the tensor interaction. First, we will examine the tensor force between a proton-neutron pair in deuterium. Secondly, we will examine the tensor force between quarks in a proton that produces a small E2 component that is mixed with the predominantly M1 excitation of the delta resonance.The magnitude of this E2 components provides a sensitive probe of the structure of the Nucleon

  10. TESTING MODELS FOR THE SHALLOW DECAY PHASE OF GAMMA-RAY BURST AFTERGLOWS WITH POLARIZATION OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Lan, Mi-Xiang; Dai, Zi-Gao [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China); Wu, Xue-Feng, E-mail: dzg@nju.edu.cn [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

    2016-08-01

    The X-ray afterglows of almost one-half of gamma-ray bursts have been discovered by the Swift satellite to have a shallow decay phase of which the origin remains mysterious. Two main models have been proposed to explain this phase: relativistic wind bubbles (RWBs) and structured ejecta, which could originate from millisecond magnetars and rapidly rotating black holes, respectively. Based on these models, we investigate polarization evolution in the shallow decay phase of X-ray and optical afterglows. We find that in the RWB model, a significant bump of the polarization degree evolution curve appears during the shallow decay phase of both optical and X-ray afterglows, while the polarization position angle abruptly changes its direction by 90°. In the structured ejecta model, however, the polarization degree does not evolve significantly during the shallow decay phase of afterglows whether the magnetic field configuration in the ejecta is random or globally large-scale. Therefore, we conclude that these two models for the shallow decay phase and relevant central engines would be testable with future polarization observations.

  11. Linear Polarization, Circular Polarization, and Depolarization of Gamma-ray Bursts: A Simple Case of Jitter Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Jirong; Wang, Jiancheng, E-mail: jirongmao@mail.ynao.ac.cn [Yunnan Observatories, Chinese Academy of Sciences, 650011 Kunming, Yunnan Province (China)

    2017-04-01

    Linear and circular polarizations of gamma-ray bursts (GRBs) have been detected recently. We adopt a simplified model to investigate GRB polarization characteristics in this paper. A compressed two-dimensional turbulent slab containing stochastic magnetic fields is considered, and jitter radiation can produce the linear polarization under this special magnetic field topology. Turbulent Faraday rotation measure (RM) of this slab makes strong wavelength-dependent depolarization. The jitter photons can also scatter with those magnetic clumps inside the turbulent slab, and a nonzero variance of the Stokes parameter V can be generated. Furthermore, the linearly and circularly polarized photons in the optical and radio bands may suffer heavy absorptions from the slab. Thus we consider the polarized jitter radiation transfer processes. Finally, we compare our model results with the optical detections of GRB 091018, GRB 121024A, and GRB 131030A. We suggest simultaneous observations of GRB multi-wavelength polarization in the future.

  12. LHCb: Probing photon polarization in Bs->phi gamma decay at LHCb

    CERN Multimedia

    Shchutska, L

    2008-01-01

    The radiative decay Bs->phi gamma is one of the benchmark channels in the physics programme of the LHCb experiment. It provides the possibility to test the Standard Model through the indirect measurement of the photon polarization in b->s gamma transition. The statistical uncertainty in the wrong polarization fraction of photons is estimated to be ~0.2 with the 2 fb^{-1} of integrated luminosity.

  13. LHCb Observation of photon polarization in the $b\\rightarrow s\\gamma$ transition

    CERN Multimedia

    Veneziano, Giovanni

    2014-01-01

    The Standard Model (SM) predicts that the photon emitted in $b\\rightarrow s\\gamma$ transitions is predominantly left-handed. While the measured inclusive $b\\rightarrow s\\gamma$ rate agrees with the SM calculations, no direct evidence exists for a nonzero photon polarization $\\lambda_\\gamma$ in this type of decays. Several extensions of the SM, compatible with all current measurements, predict that the photon acquires a significant right-handed component.

  14. Polarization of cumulative protons in the reaction. gamma. A r arrow pX

    Energy Technology Data Exchange (ETDEWEB)

    Avakyan, R.O.; Avetisyan, A.E.; Arestakesyan, G.A.; Bartikyan, M.V.; Garibyan, Y.A.; Grigoryan, A.E.; Eganov, V.S.; Karapetyan, A.P.; Karapetyan, M.P.; Keropyan, I.A.; and others

    1989-02-01

    The polarization of cumulative protons has been measured in the reaction {gamma}{ital A}{r arrow}{ital pX} in the proton-energy region 170--270 MeV for C and Sn nuclei in bremsstrahlung beams produced by 4.5- and 1.5-GeV electrons. The measured polarization value is close to zero.

  15. Polar gamma ray mode for testing weld quality natural gas pipeline

    International Nuclear Information System (INIS)

    Shahout, A. M.; Mahmood, A.Sh.

    2005-01-01

    The polar gamma-ray radiography method was studied extensively, gamma ray from Ir 192 source was used to detect weld defects in the main gas pipeline extending from Kh oms to Tripoli, gamma ray radiographic inspections were carried out according to the Astm(1) standards, and the radiographs were analyzed according to quality specifications API(2) standard-1104. The polar gamma ray mode has been applied to specimens of weld joints of pipes used in this pipeline in the reg [the kilometer 118(3)] and [the kilometer 123], and weld joints in the SLR 7 stz in the region [the kilometer 125]. The results obtained from gamma-rays have discussed and analyzed

  16. A Gamma Polarimeter for Neutron Polarization Measurement in a Liquid Deuterium Target for Parity Violation in Polarized Neutron Capture on Deuterium.

    Science.gov (United States)

    Komives, A; Sint, A K; Bowers, M; Snow, M

    2005-01-01

    A measurement of the parity-violating gamma asymmetry in n-D capture would yield information on N-N parity violation independent of the n-p system. Since cold neutrons will depolarize in a liquid deuterium target in which the scattering cross section is much larger than the absorption cross section, it will be necessary to quantify the loss of polarization before capture. One way to do this is to use the large circular polarization of the gamma from n-D capture and analyze the circular polarization of the gamma in a gamma polarimeter. We describe the design of this polarimeter.

  17. Study of the. gamma. rho. -->. n. pi. /sup +/ reaction with polarized protons and photons at E/sub. gamma. /=340 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Get' man, V.A.; Gorbenko, V.G.; Grushin, V.F.; Derkach, A.Y.; Zhebrovskii, Y.V.; Karnaukhov, I.M.; Kolesnikov, L.Y.; Lukhanin, A.A.; Rubashkin, A.L.; Sanin, V.M.; Sorokin, P.V.; Sporov, E.A.; Telegin, Y.N.

    1979-07-05

    A two-fold polarization experiment of the ''beam-target'' type is carried out for the first time for the reaction ..gamma..p..-->..n..pi../sup +/ for E/sub ..gamma../ =340 MeV, and the three polarization parameters, ..sigma.., T, and P are determined simultaneously.

  18. Possibility of determining gluon polarization via polarized top pairs in gamma-proton scattering

    International Nuclear Information System (INIS)

    Atag, S.; Billur, A.A.

    2009-01-01

    We study the possibility for directly measuring the polarized gluon distribution in the process γp→t-bar t. It is shown that polarization asymmetry of the final top quarks is proportional to the gluon polarization. With available energy and luminosity, the collision of a polarized proton beam and a Compton backscattered photon beam can create polarized top quarks which carry the spin information of the process. Energy dependence and angular distributions of the polarization asymmetry of the top pairs has been discussed including statistical uncertainty.

  19. Study of the reaction. gamma. p. --> delta. /sup + +/. pi. /sup -/ on polarized protons

    Energy Technology Data Exchange (ETDEWEB)

    Belyaev, A.; Get' man, V.; Gorbenko, V.; Gushchin, V.; Derkach, A.; Zhebrovskii, Y.; Zayats, A.; Karnaukhov, I.; Kolesnikov, L.; Lukhanin, A.; Rubashkin, A.; Sobol' , M.; Sorokin, P.; Sporov, E.; Telegin, Y.

    1982-02-01

    We have measured for the first time the asymmetry of the cross section for the reaction ..gamma..p..--> delta../sup + +/..pi../sup -/ on polarized protons. The measurements were made at E/sub ..gamma../ = 660 MeV in the range of pion emission angles 45--120/sup 0/ c.m.s. The experimental data obtained are compared with the theoretical predictions.

  20. Performance Analysis of Polarization Modulated DirectDetection Optical CDMA Systems over Turbulent FSO LinksModeled by the Gamma-Gamma Distribution

    Directory of Open Access Journals (Sweden)

    Fan Bai

    2015-01-01

    Full Text Available This paper proposes a theoretical study to characterize the transmission of optical code division multiple access (CDMA systems deploying polarization shift keying (PolSK over a free space optical (FSO link under the impact of atmospheric turbulence. In our analysis, a novel transceiver architecture for atmospheric OCDMA FSO systems based on polarization modulation with direct detection is proposed and discussed. A detailed analytical model for PolSK-OCDMA systems over a turbulent FSO link is provided. Further, we derive a closed-form bit error ratio (BER and outage probability expressions, taking into account the multiple-access interference (MAI, optical noise and the atmospheric turbulence effect on the FSO link modeled by the Gamma-Gamma distribution. Finally, the results of this study show the most significant parameters that degrade the transmission performance of the PolSK-OCDMA signal over FSO links and indicate that the proposed approach offers improved bit error ratio (BER performances compared to the on-off-keying (OOK modulation scheme in the presence of turbulence.

  1. Polarization of the prompt gamma-ray emission from the gamma-ray burst of 6 December 2002.

    Science.gov (United States)

    Coburn, Wayne; Boggs, Steven E

    2003-05-22

    Observations of the afterglows of gamma-ray bursts (GRBs) have revealed that they lie at cosmological distances, and so correspond to the release of an enormous amount of energy. The nature of the central engine that powers these events and the prompt gamma-ray emission mechanism itself remain enigmatic because, once a relativistic fireball is created, the physics of the afterglow is insensitive to the nature of the progenitor. Here we report the discovery of linear polarization in the prompt gamma-ray emission from GRB021206, which indicates that it is synchrotron emission from relativistic electrons in a strong magnetic field. The polarization is at the theoretical maximum, which requires a uniform, large-scale magnetic field over the gamma-ray emission region. A large-scale magnetic field constrains possible progenitors to those either having or producing organized fields. We suggest that the large magnetic energy densities in the progenitor environment (comparable to the kinetic energy densities of the fireball), combined with the large-scale structure of the field, indicate that magnetic fields drive the GRB explosion.

  2. DETECTION OF GAMMA-RAY POLARIZATION IN PROMPT EMISSION OF GRB 100826A

    Energy Technology Data Exchange (ETDEWEB)

    Yonetoku, Daisuke; Murakami, Toshio; Sakashita, Tomonori; Morihara, Yoshiyuki; Takahashi, Takuya; Fujimoto, Hirofumi; Kodama, Yoshiki [College of Science and Engineering, School of Mathematics and Physics, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192 (Japan); Gunji, Shuichi; Toukairin, Noriyuki [Department of Physics, Faculty of Science, Yamagata University, 1-4-12, Koshirakawa, Yamagata, Yamagata 990-8560 (Japan); Mihara, Tatehiro [Cosmic Radiation Laboratory, RIKEN, 2-1, Hirosawa, Wako City, Saitama 351-0198 (Japan); Toma, Kenji [Department of Earth and Space Science, Osaka University, Toyonaka 560-0043 (Japan); Kubo, Shin, E-mail: yonetoku@astro.s.kanazawa-u.ac.jp [Clear Pulse Co. Ltd., 6-25-17, Chuo, Ohta-ku, Tokyo 143-0024 (Japan); Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), 3-1-1, Yoshinodai, Sagamihara, Kanagawa 229-8510 (Japan)

    2011-12-20

    We report the polarization measurement in prompt {gamma}-ray emission of GRB 100826A with the Gamma-Ray Burst Polarimeter on board the small solar-power-sail demonstrator IKAROS. We detected the firm change of polarization angle (PA) during the prompt emission with 99.9% (3.5{sigma}) confidence level, and the average polarization degree ({Pi}) of 27% {+-} 11% with 99.4% (2.9{sigma}) confidence level. Here the quoted errors are given at 1{sigma} confidence level for the two parameters of interest. The systematic errors have been carefully included in this analysis, unlike other previous reports. Such a high {Pi} can be obtained in several emission models of gamma-ray bursts (GRBs), including synchrotron and photospheric models. However, it is difficult to explain the observed significant change of PA within the framework of axisymmetric jet as considered in many theoretical works. The non-axisymmetric (e.g., patchy) structures of the magnetic fields and/or brightness inside the relativistic jet are therefore required within the observable angular scale of {approx}{Gamma}{sup -1}. Our observation strongly indicates that the polarization measurement is a powerful tool to constrain the GRB production mechanism, and more theoretical works are needed to discuss the data in more detail.

  3. Polarized Gamma-Ray Emission from the Galactic Black Hole Cygnus X-1

    Science.gov (United States)

    Laurent, P.; Rodriquez, J.; Wilms, J.; Bel, M. Cadolle; Pottschmidt, K.; Grinberg, V.

    2011-01-01

    Because of their inherently high flux allowing the detection of clear signals, black hole X-ray binaries are interesting candidates for polarization studies, even if no polarization signals have been observed from them before. Such measurements would provide further detailed insight into these sources' emission mechanisms. We measured the polarization of the gamma-ray emission from the black hole binary system Cygnus X-I with the INTEGRAL/IBIS telescope. Spectral modeling ofthe data reveals two emission mechanisms: The 250-400 keY data are consistent with emission dominated by Compton scattering on thermal electrons and are weakly polarized. The second spectral component seen in the 400keV-2MeV band is by contrast strongly polarized, revealing that the MeV emission is probably related to the jet first detected in the radio band.

  4. Study of weak vacuum polarization in $Z \\to 2l \\gamma$

    CERN Document Server

    Zhabin, Viktor

    2017-01-01

    The goal of the work was to perform a search of weak vacuum polarization in the channel $Z \\to 2l \\gamma$ using $20 \\text{ fb}^{-1}$ of $pp$ collision data collected by the ATLAS experiment in 2012 at 8 TeV. The ratio of the distribution of an invariant mass of $l\\gamma$ obtained from experimental data to the MC distribution from the experimental data was used for the search of the effect. Total significance of weak vacuum polarization signal in the invariant mass distribution of $l \\gamma$ in only one of four channels has some significance. First studies indicate that an evidence of about $3.5 \\sigma$ can be reached. The parameters, amplitude and phase, determined from the fit are different in each channel and thus inconclusive.

  5. Large-Area Balloon-Borne Polarized Gamma Ray Observer (PoGO)

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, V.; Chen, P.; Kamae, T.; Madejski, G.; Mizuno, T.; Ng, J.; Tajima, H.; Thurston, T.; /SLAC; Bogaert, G.; /Ecole Polytechnique; Fukazawa, Y.; /Hiroshima U.; Saito,; Takahashi, T.; /Sagamihara, Inst. Space Astron. Sci.; Barbier, L.; Bloser, P.; Harding, A.; Hunter, S.; Krizmanic, J.; Mitchell, J.; Streitmatter, R.; Fernholz, R.; Groth, E.; /NASA, Goddard /Princeton U. /Royal Inst. Tech., Kista /Stockholm U. /Tokyo Inst. Tech. /Yamagata U.

    2005-06-30

    We are developing a new balloon-borne instrument (PoGO), to measure polarization of soft gamma rays (30-200 keV) using asymmetry in azimuth angle distribution of Compton scattering. PoGO is designed to detect 10% polarization in 100mCrab sources in a 6-8 hour observation and bring a new dimension to studies on gamma ray emission/transportation mechanism in pulsars, AGNs, black hole binaries, and neutron star surface. The concept is an adaptation to polarization measurements of well-type phoswich counter consisting of a fast plastic scintillator (the detection part), a slow plastic scintillator (the active collimator) and a BGO scintillator (the bottom anti-counter). PoGO consists of close-packed array of 217 hexagonal well-type phoswich counters and has a narrow field-of-view ({approx} 5 deg{sup 2}) to reduce possible source confusion. A prototype instrument has been tested in the polarized soft gamma-ray beams at Advanced Photon Source (ANL) and at Photon Factory (KEK). On the results, the polarization dependence of EGS4 has been validated and that of Geant4 has been corrected.

  6. Large-Area Balloon-Borne Polarized Gamma Ray Observer (PoGO)

    International Nuclear Information System (INIS)

    Andersson, V.; Chen, P.; Kamae, T.; Madejski, G.; Mizuno, T.; Ng, J.; Tajima, H.; Thurston, T.; SLAC; Bogaert, G.; Ecole Polytechnique; Fukazawa, Y.; Hiroshima U.; Saito, Y.; Takahashi, T.; Sagamihara, Inst. Space Astron. Sci.; Barbier, L.; Bloser, P.; Harding, A.; Hunter, S.; Krizmanic, J.; Mitchell, J.; Streitmatter, R.; Fernholz, R.; Groth, E.; NASA, Goddard; Princeton U.; Royal Inst. Tech., Kista; Stockholm U.; Tokyo Inst. Tech.; Yamagata U.

    2005-01-01

    We are developing a new balloon-borne instrument (PoGO), to measure polarization of soft gamma rays (30-200 keV) using asymmetry in azimuth angle distribution of Compton scattering. PoGO is designed to detect 10% polarization in 100mCrab sources in a 6-8 hour observation and bring a new dimension to studies on gamma ray emission/transportation mechanism in pulsars, AGNs, black hole binaries, and neutron star surface. The concept is an adaptation to polarization measurements of well-type phoswich counter consisting of a fast plastic scintillator (the detection part), a slow plastic scintillator (the active collimator) and a BGO scintillator (the bottom anti-counter). PoGO consists of close-packed array of 217 hexagonal well-type phoswich counters and has a narrow field-of-view (∼ 5 deg 2 ) to reduce possible source confusion. A prototype instrument has been tested in the polarized soft gamma-ray beams at Advanced Photon Source (ANL) and at Photon Factory (KEK). On the results, the polarization dependence of EGS4 has been validated and that of Geant4 has been corrected

  7. Analyzing power of AGATA triple clusters for gamma-ray linear polarization

    Energy Technology Data Exchange (ETDEWEB)

    Bizzeti, P.G.; Sona, P.; Melon, B.; Bizzeti-Sona, A.M.; Perego, A. [Universita di Firenze, Dipartimento di Fisica, Firenze (Italy); INFN, Firenze (Italy); Michelagnoli, C.; Lunardi, S.; Mengoni, D.; Recchia, F. [INFN, Padova (Italy); Universita di Padova, Dipartimento di Fisica, Padova (Italy); Bazzacco, D.; Farnea, E.; Menegazzo, R.; Ur, C.A. [INFN, Padova (Italy); De Angelis, G.; Gottardo, A.; Napoli, D.R.; Sahin, E.; Valiente-Dobon, J.J. [Laboratori Nazionali di Legnaro, INFN, Padova (Italy); Gadea, A. [University of Valencia, IFIC, CSIC, Valencia (Spain); Nannini, A. [INFN, Firenze (Italy)

    2015-04-01

    We have investigated the ability of AGATA triple clusters to measure the linear polarization of gamma rays, exploiting the azimuthal-angle dependence of the Compton scattering differential cross section. To this aim, partially polarized gamma rays have been produced by Coulomb excitation of the first excited state of {sup 104}Pd and {sup 108}Pd, which decay to the ground state by emission of gamma rays of 555.8 keV and 433.9 keV, respectively. Pulse-shape analysis and gamma-ray tracking techniques have been used to determine the position and time sequence of the interaction points inside the germanium crystals. Anisotropies in the detection efficiency have been taken into account using 661.6 keV gammas from a {sup 137}Cs radioactive source. We obtain an average analyzing power of 0.451(34) at 433.9 keV and 0.484(24) at 555.8 keV. (orig.)

  8. Development of the POLAR experiment for the gamma-ray bursts polarimetry

    Science.gov (United States)

    Zwolinska, Anna

    2017-01-01

    The polarimetric data taken together with lightcurve and spectral data may provide a powerful probe of the nature of sources and emission mechanisms of Gamma-ray Bursts (GRBs). We would like to know if most of the GRBs are strongly polarized. There were several reports of detections of linear polarization but more accurate observational data and the statistical study are still needed. The POLAR experiment is a space-born polarimeter designed for measurement of γ-ray in the energy range 50-500 keV. The detector was mounted onto the Chinese Tiangong 2 space station in 2016. The preflight status of the POLAR experiment has been presented in the talk.

  9. Gamma and proton induced degradation in ceramics materials - A proposal

    International Nuclear Information System (INIS)

    Constantinescu, B.

    2001-01-01

    Ceramic materials will play very important roles in developing fusion reactors, where they will be used under heavy irradiation environments (neutrons, gamma-rays, protons, helium and other ions) for substantial periods for the first time. The programme at the Institute of Atomic Physics in Bucharest forms a part of the on going ceramics programmes to assess the suitability of SiO2 based materials for both diagnostic and remote handling application. The authors' proposal focuses on comparison of the ionization and displacement induced damage (influence on the UV and visible optical transmission properties) and on radiation enhanced hydrogen isotope diffusion in these materials; the work is performed in cooperation with CIEMAT Madrid and SCK/CEN Mol. The irradiation facilities are: IRASM - 200 kCi Co-60 source, minimum 2kGy/h, ethanol chlorine benzene and ESR dosimetry; HVEC 8 MV TANDEM - protons up to 16 MeV and 200 nA; and 600 kV DISKTRON - H isotopes up to 600 keV, tens of microamperes. (author)

  10. Large-Area Balloon-Borne Polarized Gamma Ray Observer (PoGO)

    International Nuclear Information System (INIS)

    Blanford, R.

    2005-01-01

    We are developing a new balloon-borne instrument (PoGO), to measure polarization of soft gamma rays (25-200 keV) using asymmetry in azimuth angle distribution of Compton scattering. PoGO will detect 10% polarization in 100mCrab sources in a 6-8 hour observation and bring a new dimension to studies on gamma ray emission/transportation mechanism in pulsars, AGNs, black hole binaries, and neutron star surface. The concept is an adaptation to polarization measurements of well-type phoswich counter technology used in balloon-borne experiments (Welcome-1) and AstroE2 Hard X-ray Detector. PoGO consists of close-packed array of 397 hexagonal well-type phoswich counters. Each unit is composed of a long thin tube (well) of slow plastic scintillator, a solid rod of fast plastic scintillator, and a short BGO at the base. A photomultiplier coupled to the end of the BGO detects light from all 3 scintillators. The rods with decay times 2 ) strike a fast scintillator, some are Compton scattered. A fraction of the scattered photons are absorbed in another rod (or undergo a second scatter). A valid event requires one clean fast signal of pulse-height compatible with photo-absorption (> 20keV) and one or more compatible with Compton scattering (< 10keV). Studies based on EGS4 (with polarization features) and Geant4 predict excellent background rejection and high sensitivity

  11. 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...

  12. Photon polarization in $B_s^0 \\to \\phi \\gamma$ decays at the LHCb experiment

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00392538; Martínez Vidal, Fernando

    The Standard Model predicts a predominance of left handed photons emitted in the $b \\to s\\gamma$ interaction, due to the coupling of the $W$ boson to only left handed quarks. Moreso, several Beyond Standard Model theories predict an enhancement of right handed photon emission. A measurement of the photon polairization is therefore a direct probe of New Physics. The photon polarization sensible parameter $\\mathcal{A}^\\Delta$ is measured through a fit to the ratio of untagged time dependent decay rates of $B_s^0 \\to \\phi \\gamma$ over that of $B^0 \\to K^\\ast \\gamma$, the former being sensitive to the parameter because of its non-negligible decay width difference (Phys.Lett.B664:174-179,2008) and the latter being the control channel due to its kinematical similarities and sixfold larger yield. Using 3 fb$^{-1}$ of data collected at LHCb during 2011 and 2012 at centre of mass energies of 7 and 8 TeV, respectively, 4200 $B_s^0 \\to \\phi \\gamma$ and 25700 $B^0 \\to K^\\ast \\gamma$ events are reconstructed. The selecti...

  13. Large-Area Balloon-Borne Polarized Gamma Ray Observer (PoGO)

    Energy Technology Data Exchange (ETDEWEB)

    Blanford, R.

    2005-04-06

    We are developing a new balloon-borne instrument (PoGO), to measure polarization of soft gamma rays (25-200 keV) using asymmetry in azimuth angle distribution of Compton scattering. PoGO will detect 10% polarization in 100mCrab sources in a 6-8 hour observation and bring a new dimension to studies on gamma ray emission/transportation mechanism in pulsars, AGNs, black hole binaries, and neutron star surface. The concept is an adaptation to polarization measurements of well-type phoswich counter technology used in balloon-borne experiments (Welcome-1) and AstroE2 Hard X-ray Detector. PoGO consists of close-packed array of 397 hexagonal well-type phoswich counters. Each unit is composed of a long thin tube (well) of slow plastic scintillator, a solid rod of fast plastic scintillator, and a short BGO at the base. A photomultiplier coupled to the end of the BGO detects light from all 3 scintillators. The rods with decay times < 10 ns, are used as the active elements; while the wells and BGOs, with decay times {approx}250 ns are used as active anti-coincidence. The fast and slow signals are separated out electronically. When gamma rays entering the field-of-view (fwhm {approx} 3deg{sup 2}) strike a fast scintillator, some are Compton scattered. A fraction of the scattered photons are absorbed in another rod (or undergo a second scatter). A valid event requires one clean fast signal of pulse-height compatible with photo-absorption (> 20keV) and one or more compatible with Compton scattering (< 10keV). Studies based on EGS4 (with polarization features) and Geant4 predict excellent background rejection and high sensitivity.

  14. Rotational inertia of continents: A proposed link between polar wandering and plate tectonics

    Science.gov (United States)

    Kane, M.F.

    1972-01-01

    A mechanism is proposed whereby displacement between continents and the earth's pole of rotation (polar wandering) gives rise to latitudinal transport of continental plates (continental drift) because of their relatively greater rotational inertia. When extended to short-term polar wobble, the hypothesis predicts an energy change nearly equivalent to the seismic energy rate.

  15. The Gamma-Ray Burst Polarimeter - POLAR onboard the China’s Spacelab “Tiangong-2”

    Science.gov (United States)

    Sun, Jianchao; BAO, T. W.; BATSCH, T.; BRITVITCH, I.; CADOUX, F.; DONG, Y. W.; GAUVIN, N.; HAJDAS, W.; KOLE, M.; LECHANOINE-LELUC, C.; LI, L.; MARCINKOWSKI, R.; ORSI, S.; POHL, M.; PRODUIT, N.; RAPIN, D.; RUTCZYNSKA, A.; RYBKA, D.; SZABELSKI, J.; WANG, R. J.; WU, B. B.; XIAO, H. L.; ZHANG, S. N.; ZHANG, Y. J.; ZWOLINSKA, A.

    2015-08-01

    POLAR is a novel compact space-borne Compton polarimeter conceived for a precise measurement of hard X-ray/Gamma-ray polarization and optimized for the detection of the prompt emission of Gamma-Ray Bursts (GRB) in the energy range 50 - 500 keV. The future detailed measurement of the polarization of GRB will lead to a better understanding of its radiation region geometry and emission mechanisms. Thanks to its remarkable properties on large effective area, field of view (4.14 sr or 1/3 of the visible sky) and obvious modulation factor, POLAR will be able to reach a minimum detectable polarization (1-σ level) of about 3% for several GRB measurements per year. POLAR consists of 25 detector modular units (DMU). Each DMU is composed of 64 low-Z plastic scintillator bars, read out by a flat-panel multi-anode photomultipliers and ASIC front-end electronics. The incoming photons undergo Compton scattering in the bars and produce a modulation pattern. Simulations and hard X-ray synchrotron radiation experiments have shown that the polarization degree and angle can be retrieved from this pattern with the accuracy necessary for pinning down the GRB mechanisms. A full flight model of POLAR has been constructed, in view of a flight on the Chinese spacelab TG-2 expected in 2016. The design of POLAR, Monte-Carlo simulation analysis as well as the performance test results will be all addressed in details in this talk.

  16. Polarized beam asymmetry for. gamma. d. -->. Peta in the energy range 0. 4-0. 8 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Adamyan, F.V.; Arustamyan, G.V.; Galumyan, P.I.; Grabsky, V.H.; Hakopyan, H.H.; Karapetyan, V.V.; Vartapetyan, H.A.

    1983-01-01

    Measurements of the polarized beam asymmetry for deuteron photodisintegration ..gamma..d ..-->.. Peta have been carried out in the energy range E/sub ..gamma../ = 0.4-0.8 GeV and at angles theta/sub p//sup cm/ = 45/sup 0/-75/sup 0/. The results obtained are in disagreement with theoretical predictions which take into account the dibaryon resonance contribution. The data qualitative analysis indicates the weakness of isoscalar dibaryon amplitudes near E/sub ..gamma../ = 400 MeV. 8 references, 1 figure.

  17. Proposed method to produce a highly polarized e+ beam for future linear colliders

    International Nuclear Information System (INIS)

    Okugi, Toshiyuki; Chiba, Masami; Kurihara, Yoshimasa

    1996-01-01

    We propose a method to produce a spin-polarized e + beam using e + e - pair-creation by circularly polarized photons. Assuming Compton scattering of an unpolarized e - beam and circularly polarized laser light, scattered γ-rays at the high end of the energy spectrum are also circularly polarized. If those γ-rays are utilized to create e ± pairs on a thin target, the spin-polarization is preserved for e + 's at the high end of their energy spectrum. By using the injector linac of Accelerator Test Facility at KEK and a commercially available Nd:YAG pulse laser, we can expect about 10 5 polarized e + 's per second with a degree of polarization of 80% and a kinetic energy of 35-80 MeV. The apparatus for creation and measurement of polarized e + 's is being constructed. We present new idea for possible application of our method to future linear colliders by utilizing a high-power CO 2 laser. (author)

  18. The influence of gamma radiation on polarization mode dispersion of fibers applied in communications

    Directory of Open Access Journals (Sweden)

    Sekulić Rade S.

    2012-01-01

    Full Text Available The fiber optics technology is constantly being developed, and is becoming an essential component of contemporary communications, medicine and industry. Fibers, their connections and system components play a major role in optical signal transmission, telecommunications, power transmission, and sensing processes using fiber technology. The two main light propagation characteristics of an optical fiber are attenuation and dispersion. The possibility of controling these parameters is of utmost importance for obtaining the requested transmission quality. This paper reports on an investigation to determine the influence of gamma radiation of 60Co on the variation of optical fiber propagation parameters, such as polarization mode dispersion. In addition, it also considers chosen topics in the field of fiber optics technology.

  19. POLAR on board of the Tiangong 2 Chinese space station: measuring the polarization of hard X-rays photons, in particular the polarization of prompt photons from gamma ray bursts.

    Science.gov (United States)

    Produit, Nicolas

    2012-07-01

    POLAR is an homogeneous wide field Compton polarimeter using plastic scintillators and multichannel photomultipliers. The goal of this polarimeter is to measure with controlled systematics the polarization of hard X-ray emitted by unpredictable transient sources The instrument energy range sensitivity is optimized for the detection of the prompt emission of Gamma-Ray Bursts (GRB). Monte-Carlo studies and calibration data collected in polarized photon beams predict that POLAR will be able to measure the polarization degree of 10 GRB per year with a combined systematics and statistical accuracy of better then 10%. POLAR will be mounted outside of the Tiangong 2 Chinese space station that will be launched in space in 2014.

  20. A New Limit on Planck Scale Lorentz Violation from Gamma-ray Burst Polarization

    Science.gov (United States)

    Stecker, Floyd W.

    2011-01-01

    Constraints on possible Lorentz invariance violation (UV) to first order in E/M(sub Plank) for photons in the framework of effective field theory (EFT) are discussed, taking cosmological factors into account. Then. using the reported detection of polarized soft gamma-ray emission from the gamma-ray burst GRB041219a that is indicative' of an absence of vacuum birefringence, together with a very recent improved method for estimating the redshift of the burst, we derive constraints on the dimension 5 Lorentz violating modification to the Lagrangian of an effective local QFT for QED. Our new constraints are more than five orders of magnitude better than recent constraints from observations of the Crab Nebula.. We obtain the upper limit on the Lorentz violating dimension 5 EFT parameter absolute value of zeta of 2.4 x 10(exp -15), corresponding to a constraint on the dimension 5 standard model extension parameter. Kappa (sup 5) (sub (v)oo) much less than 4.2 X 10(exp -3)4 / GeV.

  1. Observation of photon polarization in the $b \\to s\\gamma$ transition

    CERN Document Server

    Aaij, Roel; Adinolfi, Marco; Affolder, Anthony; Ajaltouni, Ziad; Albrecht, Johannes; Alessio, Federico; Alexander, Michael; Ali, Suvayu; Alkhazov, Georgy; Alvarez Cartelle, Paula; Alves Jr, Antonio; Amato, Sandra; Amerio, Silvia; Amhis, Yasmine; Anderlini, Lucio; Anderson, Jonathan; Andreassen, Rolf; Andreotti, Mirco; Andrews, Jason; Appleby, Robert; Aquines Gutierrez, Osvaldo; Archilli, Flavio; Artamonov, Alexander; Artuso, Marina; Aslanides, Elie; Auriemma, Giulio; Baalouch, Marouen; Bachmann, Sebastian; Back, John; Badalov, Alexey; Balagura, Vladislav; Baldini, Wander; Barlow, Roger; Barschel, Colin; Barsuk, Sergey; Barter, William; Batozskaya, Varvara; Bauer, Thomas; Bay, Aurelio; Beddow, John; Bedeschi, Franco; Bediaga, Ignacio; Belogurov, Sergey; Belous, Konstantin; Belyaev, Ivan; Ben-Haim, Eli; Bencivenni, Giovanni; Benson, Sean; Benton, Jack; Berezhnoy, Alexander; Bernet, Roland; Bettler, Marc-Olivier; van Beuzekom, Martinus; Bien, Alexander; Bifani, Simone; Bird, Thomas; Bizzeti, Andrea; Bjørnstad, Pål Marius; Blake, Thomas; Blanc, Frédéric; Blouw, Johan; Blusk, Steven; Bocci, Valerio; Bondar, Alexander; Bondar, Nikolay; Bonivento, Walter; Borghi, Silvia; Borgia, Alessandra; Borsato, Martino; Bowcock, Themistocles; Bowen, Espen Eie; Bozzi, Concezio; Brambach, Tobias; van den Brand, Johannes; Bressieux, Joël; Brett, David; Britsch, Markward; Britton, Thomas; Brook, Nicholas; Brown, Henry; Bursche, Albert; Busetto, Giovanni; Buytaert, Jan; Cadeddu, Sandro; Calabrese, Roberto; Callot, Olivier; Calvi, Marta; Calvo Gomez, Miriam; Camboni, Alessandro; Campana, Pierluigi; Campora Perez, Daniel; Caponio, Francesco; Carbone, Angelo; Carboni, Giovanni; Cardinale, Roberta; Cardini, Alessandro; Carranza-Mejia, Hector; Carson, Laurence; Carvalho Akiba, Kazuyoshi; Casse, Gianluigi; Cassina, Lorenzo; Castillo Garcia, Lucia; Cattaneo, Marco; Cauet, Christophe; Cenci, Riccardo; Charles, Matthew; Charpentier, Philippe; Cheung, Shu-Faye; Chiapolini, Nicola; Chrzaszcz, Marcin; Ciba, Krzystof; Cid Vidal, Xabier; Ciezarek, Gregory; Clarke, Peter; Clemencic, Marco; Cliff, Harry; Closier, Joel; Coca, Cornelia; Coco, Victor; Cogan, Julien; Cogneras, Eric; Collins, Paula; Comerma-Montells, Albert; Contu, Andrea; Cook, Andrew; Coombes, Matthew; Coquereau, Samuel; Corti, Gloria; Counts, Ian; Couturier, Benjamin; Cowan, Greig; Craik, Daniel Charles; Cruz Torres, Melissa Maria; Cunliffe, Samuel; Currie, Robert; D'Ambrosio, Carmelo; Dalseno, Jeremy; David, Pascal; David, Pieter; Davis, Adam; De Bonis, Isabelle; De Bruyn, Kristof; De Capua, Stefano; De Cian, Michel; De Miranda, Jussara; De Paula, Leandro; De Silva, Weeraddana; De Simone, Patrizia; Decamp, Daniel; Deckenhoff, Mirko; Del Buono, Luigi; Déléage, Nicolas; Derkach, Denis; Deschamps, Olivier; Dettori, Francesco; Di Canto, Angelo; Dijkstra, Hans; Donleavy, Stephanie; Dordei, Francesca; Dorigo, Mirco; Dorosz, Piotr; Dosil Suárez, Alvaro; Dossett, David; Dovbnya, Anatoliy; Dupertuis, Frederic; Durante, Paolo; Dzhelyadin, Rustem; Dziurda, Agnieszka; Dzyuba, Alexey; Easo, Sajan; Egede, Ulrik; Egorychev, Victor; Eidelman, Semen; Eisenhardt, Stephan; Eitschberger, Ulrich; Ekelhof, Robert; Eklund, Lars; El Rifai, Ibrahim; Elsasser, Christian; Esen, Sevda; Falabella, Antonio; Färber, Christian; Farinelli, Chiara; Farry, Stephen; Ferguson, Dianne; Fernandez Albor, Victor; Ferreira Rodrigues, Fernando; Ferro-Luzzi, Massimiliano; Filippov, Sergey; Fiore, Marco; Fiorini, Massimiliano; Fitzpatrick, Conor; Fontana, Marianna; Fontanelli, Flavio; Forty, Roger; Francisco, Oscar; Frank, Markus; Frei, Christoph; Frosini, Maddalena; Fu, Jinlin; Furfaro, Emiliano; Gallas Torreira, Abraham; Galli, Domenico; Gambetta, Silvia; Gandelman, Miriam; Gandini, Paolo; Gao, Yuanning; Garofoli, Justin; Garra Tico, Jordi; Garrido, Lluis; Gaspar, Clara; Gauld, Rhorry; Gavardi, Laura; Gersabeck, Evelina; Gersabeck, Marco; Gershon, Timothy; Ghez, Philippe; Gianelle, Alessio; Giani', Sebastiana; Gibson, Valerie; Giubega, Lavinia-Helena; Gligorov, Vladimir; Göbel, Carla; Golubkov, Dmitry; Golutvin, Andrey; Gomes, Alvaro; Gordon, Hamish; Grabalosa Gándara, Marc; Graciani Diaz, Ricardo; Granado Cardoso, Luis Alberto; Graugés, Eugeni; Graziani, Giacomo; Grecu, Alexandru; Greening, Edward; Gregson, Sam; Griffith, Peter; Grillo, Lucia; Grünberg, Oliver; Gui, Bin; Gushchin, Evgeny; Guz, Yury; Gys, Thierry; Hadjivasiliou, Christos; Haefeli, Guido; Haen, Christophe; Hafkenscheid, Tom; Haines, Susan; Hall, Samuel; Hamilton, Brian; Hampson, Thomas; Hansmann-Menzemer, Stephanie; Harnew, Neville; Harnew, Samuel; Harrison, Jonathan; Hartmann, Thomas; He, Jibo; Head, Timothy; Heijne, Veerle; Hennessy, Karol; Henrard, Pierre; Henry, Louis; Hernando Morata, Jose Angel; van Herwijnen, Eric; Heß, Miriam; Hicheur, Adlène; Hill, Donal; Hoballah, Mostafa; Hombach, Christoph; Hulsbergen, Wouter; Hunt, Philip; Hussain, Nazim; Hutchcroft, David; Hynds, Daniel; Idzik, Marek; Ilten, Philip; Jacobsson, Richard; Jaeger, Andreas; Jans, Eddy; Jaton, Pierre; Jawahery, Abolhassan; Jing, Fanfan; John, Malcolm; Johnson, Daniel; Jones, Christopher; Joram, Christian; Jost, Beat; Jurik, Nathan; Kaballo, Michael; Kandybei, Sergii; Kanso, Wallaa; Karacson, Matthias; Karbach, Moritz; Kelsey, Matthew; Kenyon, Ian; Ketel, Tjeerd; Khanji, Basem; Khurewathanakul, Chitsanu; Klaver, Suzanne; Kochebina, Olga; Komarov, Ilya; Koopman, Rose; Koppenburg, Patrick; Korolev, Mikhail; Kozlinskiy, Alexandr; Kravchuk, Leonid; Kreplin, Katharina; Kreps, Michal; Krocker, Georg; Krokovny, Pavel; Kruse, Florian; Kucharczyk, Marcin; Kudryavtsev, Vasily; Kurek, Krzysztof; Kvaratskheliya, Tengiz; La Thi, Viet Nga; Lacarrere, Daniel; Lafferty, George; Lai, Adriano; Lambert, Dean; Lambert, Robert W; Lanciotti, Elisa; Lanfranchi, Gaia; Langenbruch, Christoph; Langhans, Benedikt; Latham, Thomas; Lazzeroni, Cristina; Le Gac, Renaud; van Leerdam, Jeroen; Lees, Jean-Pierre; Lefèvre, Regis; Leflat, Alexander; Lefrançois, Jacques; Leo, Sabato; Leroy, Olivier; Lesiak, Tadeusz; Leverington, Blake; Li, Yiming; Liles, Myfanwy; Lindner, Rolf; Linn, Christian; Lionetto, Federica; Liu, Bo; Liu, Guoming; Lohn, Stefan; Longstaff, Ian; Lopes, Jose; Lopez-March, Neus; Lowdon, Peter; Lu, Haiting; Lucchesi, Donatella; Luo, Haofei; Luppi, Eleonora; Lupton, Oliver; Machefert, Frederic; Machikhiliyan, Irina V; Maciuc, Florin; Maev, Oleg; Malde, Sneha; Manca, Giulia; Mancinelli, Giampiero; Manzali, Matteo; Maratas, Jan; Marconi, Umberto; Marin Benito, Carla; Marino, Pietro; Märki, Raphael; Marks, Jörg; Martellotti, Giuseppe; Martens, Aurelien; Martín Sánchez, Alexandra; Martinelli, Maurizio; Martinez Santos, Diego; Martinez Vidal, Fernando; Martins Tostes, Danielle; Massafferri, André; Matev, Rosen; Mathe, Zoltan; Matteuzzi, Clara; Mazurov, Alexander; McCann, Michael; McCarthy, James; McNab, Andrew; McNulty, Ronan; McSkelly, Ben; Meadows, Brian; Meier, Frank; Meissner, Marco; Merk, Marcel; Milanes, Diego Alejandro; Minard, Marie-Noelle; Molina Rodriguez, Josue; Monteil, Stephane; Moran, Dermot; Morandin, Mauro; Morawski, Piotr; Mordà, Alessandro; Morello, Michael Joseph; Mountain, Raymond; Muheim, Franz; Müller, Katharina; Muresan, Raluca; Muryn, Bogdan; Muster, Bastien; Naik, Paras; Nakada, Tatsuya; Nandakumar, Raja; Nasteva, Irina; Needham, Matthew; Neri, Nicola; Neubert, Sebastian; Neufeld, Niko; Nguyen, Anh Duc; Nguyen, Thi-Dung; Nguyen-Mau, Chung; Nicol, Michelle; Niess, Valentin; Niet, Ramon; Nikitin, Nikolay; Nikodem, Thomas; Novoselov, Alexey; Oblakowska-Mucha, Agnieszka; Obraztsov, Vladimir; Oggero, Serena; Ogilvy, Stephen; Okhrimenko, Oleksandr; Oldeman, Rudolf; Onderwater, Gerco; Orlandea, Marius; Otalora Goicochea, Juan Martin; Owen, Patrick; Oyanguren, Maria Arantza; Pal, Bilas Kanti; Palano, Antimo; Palombo, Fernando; Palutan, Matteo; Panman, Jacob; Papanestis, Antonios; Pappagallo, Marco; Pappalardo, Luciano; Parkes, Christopher; Parkinson, Christopher John; Passaleva, Giovanni; Patel, Girish; Patel, Mitesh; Patrignani, Claudia; Pavel-Nicorescu, Carmen; Pazos Alvarez, Antonio; Pearce, Alex; Pellegrino, Antonio; Pepe Altarelli, Monica; Perazzini, Stefano; Perez Trigo, Eliseo; Perret, Pascal; Perrin-Terrin, Mathieu; Pescatore, Luca; Pesen, Erhan; Pessina, Gianluigi; Petridis, Konstantin; Petrolini, Alessandro; Picatoste Olloqui, Eduardo; Pietrzyk, Boleslaw; Pilař, Tomas; Pinci, Davide; Pistone, Alessandro; Playfer, Stephen; Plo Casasus, Maximo; Polci, Francesco; Poluektov, Anton; Polycarpo, Erica; Popov, Alexander; Popov, Dmitry; Popovici, Bogdan; Potterat, Cédric; Powell, Andrew; Prisciandaro, Jessica; Pritchard, Adrian; Prouve, Claire; Pugatch, Valery; Puig Navarro, Albert; Punzi, Giovanni; Qian, Wenbin; Rachwal, Bartolomiej; Rademacker, Jonas; Rakotomiaramanana, Barinjaka; Rama, Matteo; Rangel, Murilo; Raniuk, Iurii; Rauschmayr, Nathalie; Raven, Gerhard; Reichert, Stefanie; Reid, Matthew; dos Reis, Alberto; Ricciardi, Stefania; Richards, Alexander; Rinnert, Kurt; Rives Molina, Vincente; Roa Romero, Diego; Robbe, Patrick; Roberts, Douglas; Rodrigues, Ana Barbara; Rodrigues, Eduardo; Rodriguez Perez, Pablo; Roiser, Stefan; Romanovsky, Vladimir; Romero Vidal, Antonio; Rotondo, Marcello; Rouvinet, Julien; Ruf, Thomas; Ruffini, Fabrizio; Ruiz, Hugo; Ruiz Valls, Pablo; Sabatino, Giovanni; Saborido Silva, Juan Jose; Sagidova, Naylya; Sail, Paul; Saitta, Biagio; Salustino Guimaraes, Valdir; Sanmartin Sedes, Brais; Santacesaria, Roberta; Santamarina Rios, Cibran; Santovetti, Emanuele; Sapunov, Matvey; Sarti, Alessio; Satriano, Celestina; Satta, Alessia; Savrie, Mauro; Savrina, Darya; Schiller, Manuel; Schindler, Heinrich; Schlupp, Maximilian; Schmelling, Michael; Schmidt, Burkhard; Schneider, Olivier; Schopper, Andreas; Schune, Marie Helene; Schwemmer, Rainer; Sciascia, Barbara; Sciubba, Adalberto; Seco, Marcos; Semennikov, Alexander; Senderowska, Katarzyna; Sepp, Indrek; Serra, Nicola; Serrano, Justine; Seyfert, Paul; Shapkin, Mikhail; Shapoval, Illya; Shcheglov, Yury; Shears, Tara; Shekhtman, Lev; Shevchenko, Oksana; Shevchenko, Vladimir; Shires, Alexander; Silva Coutinho, Rafael; Simi, Gabriele; Sirendi, Marek; Skidmore, Nicola; Skwarnicki, Tomasz; Smith, Anthony; Smith, Edmund; Smith, Eluned; Smith, Jackson; Smith, Mark; Snoek, Hella; Sokoloff, Michael; Soler, Paul; Soomro, Fatima; Souza, Daniel; Souza De Paula, Bruno; Spaan, Bernhard; Sparkes, Ailsa; Spinella, Franco; Spradlin, Patrick; Stagni, Federico; Stahl, Sascha; Steinkamp, Olaf; Stevenson, Scott; Stoica, Sabin; Stone, Sheldon; Storaci, Barbara; Stracka, Simone; Straticiuc, Mihai; Straumann, Ulrich; Stroili, Roberto; Subbiah, Vijay Kartik; Sun, Liang; Sutcliffe, William; Swientek, Stefan; Syropoulos, Vasileios; Szczekowski, Marek; Szczypka, Paul; Szilard, Daniela; Szumlak, Tomasz; T'Jampens, Stephane; Teklishyn, Maksym; Tellarini, Giulia; Teodorescu, Eliza; Teubert, Frederic; Thomas, Christopher; Thomas, Eric; van Tilburg, Jeroen; Tisserand, Vincent; Tobin, Mark; Tolk, Siim; Tomassetti, Luca; Tonelli, Diego; Topp-Joergensen, Stig; Torr, Nicholas; Tournefier, Edwige; Tourneur, Stephane; Tran, Minh Tâm; Tresch, Marco; Tsaregorodtsev, Andrei; Tsopelas, Panagiotis; Tuning, Niels; Ubeda Garcia, Mario; Ukleja, Artur; Ustyuzhanin, Andrey; Uwer, Ulrich; Vagnoni, Vincenzo; Valenti, Giovanni; Vallier, Alexis; Vazquez Gomez, Ricardo; Vazquez Regueiro, Pablo; Vázquez Sierra, Carlos; Vecchi, Stefania; Velthuis, Jaap; Veltri, Michele; Veneziano, Giovanni; Vesterinen, Mika; Viaud, Benoit; Vieira, Daniel; Vilasis-Cardona, Xavier; Vollhardt, Achim; Volyanskyy, Dmytro; Voong, David; Vorobyev, Alexey; Vorobyev, Vitaly; Voß, Christian; Voss, Helge; de Vries, Jacco; Waldi, Roland; Wallace, Charlotte; Wallace, Ronan; Wandernoth, Sebastian; Wang, Jianchun; Ward, David; Watson, Nigel; Webber, Adam Dane; Websdale, David; Whitehead, Mark; Wicht, Jean; Wiechczynski, Jaroslaw; Wiedner, Dirk; Wilkinson, Guy; Williams, Matthew; Williams, Mike; Wilson, Fergus; Wimberley, Jack; Wishahi, Julian; Wislicki, Wojciech; Witek, Mariusz; Wormser, Guy; Wotton, Stephen; Wright, Simon; Wu, Suzhi; Wyllie, Kenneth; Xie, Yuehong; Xing, Zhou; Yang, Zhenwei; Yuan, Xuhao; Yushchenko, Oleg; Zangoli, Maria; Zavertyaev, Mikhail; Zhang, Feng; Zhang, Liming; Zhang, Wen Chao; Zhang, Yanxi; Zhelezov, Alexey; Zhokhov, Anatoly; Zhong, Liang; Zvyagin, Alexander

    2014-01-01

    This Letter presents a study of the flavor-changing neutral current radiative $B^{\\pm} \\to K^{\\pm}\\pi^{\\mp}\\pi^{\\pm}\\gamma$ decays performed using data collected in proton-proton collisions with the LHCb detector at $7$ and $8\\,$TeV center-of-mass energies. In this sample, corresponding to an integrated luminosity of $3\\,\\text{fb}^{-1}$, nearly $14\\,000$ signal events are reconstructed and selected, containing all possible intermediate resonances with a $K^{\\pm}\\pi^{\\mp}\\pi^{\\pm}$ final state in the $[1.1, 1.9]\\,$GeV/$c^{2}$ mass range. The distribution of the angle of the photon direction with respect to the plane defined by the final-state hadrons in their rest frame is studied in intervals of $K^{\\pm}\\pi^{\\mp}\\pi^{\\pm}$ mass and the asymmetry between the number of signal events found on each side of the plane is obtained. The first direct observation of the photon polarization in the $b \\to s\\gamma$ transition is reported with a significance of $5.2\\,\\sigma$.

  2. New model for assessing dose and dose rate sensitivity of Gamma ray radiation loss in polarization maintaining optical fibers

    International Nuclear Information System (INIS)

    Zhang Hongchen; Liu Hai; Qiao Wenqiang; Xue Huijie; He Shiyu

    2012-01-01

    Highlights: ► Building a new phenomenological theory model to investigate the relation about the irradiation induced loss with irradiation dose and dose rate. ► The Gamma ray irradiation induced loss of the “Capsule” type and “Panda” type polarization maintaining optical fibers at 1310 nm wavelength are investigated. ► The anti irradiation performance of the “Panda” type polarization maintaining optical fiber is better than that of the “Capsule” type polarization maintaining optical fiber, the reason is that the stress region doped by GeO 2 . - Abstract: The Gamma ray irradiation induced loss of the “Capsule” type and “Panda” type polarization maintaining optical fibers at 1310 nm wavelength are investigated. A phenomenological theory model is introduced and the influence of irradiation dose and dose rate on the irradiation induced loss is discussed. The phenomenological theoretical results are consistent with the experimental results of the irradiation induced loss for the two types of polarization maintaining optical fibers. The anti irradiation performance of the “Panda” type polarization maintaining optical fiber is better than that of the “Capsule” type polarization maintaining optical fiber, the reason is that the stress region dope with GeO 2 . Meanwhile, both of the polarization maintaining optical fiber irradiation induced loss increase with increasing the irradiation dose. In the case of same dose, the high dose rate Gamma ray irradiation induced optical fiber losses are higher than that of the low dose rate.

  3. Determining the true polarity and amplitude of synaptic currents underlying gamma oscillations of local field potentials.

    Directory of Open Access Journals (Sweden)

    Gonzalo Martín-Vázquez

    Full Text Available Fluctuations in successive waves of oscillatory local field potentials (LFPs reflect the ongoing processing of neuron populations. However, their amplitude, polarity and synaptic origin are uncertain due to the blending of electric fields produced by multiple converging inputs, and the lack of a baseline in standard AC-coupled recordings. Consequently, the estimation of underlying currents by laminar analysis yields spurious sequences of inward and outward currents. We devised a combined analytical/experimental approach that is suitable to study laminated structures. The approach was essayed on an experimental oscillatory LFP as the Schaffer-CA1 gamma input in anesthetized rats, and it was verified by parallel processing of model LFPs obtained through a realistic CA1 aggregate of compartmental units. This approach requires laminar LFP recordings and the isolation of the oscillatory input from other converging pathways, which was achieved through an independent component analysis. It also allows the spatial and temporal components of pathway-specific LFPs to be separated. While reconstructed Schaffer-specific LFPs still show spurious inward/outward current sequences, these were clearly stratified into distinct subcellular domains. These spatial bands guided the localized delivery of neurotransmitter blockers in experiments. As expected, only Glutamate but not GABA blockers abolished Schaffer LFPs when applied to the active but not passive subcellular domains of pyramidal cells. The known chemical nature of the oscillatory LFP allowed an empirical offset of the temporal component of Schaffer LFPs, such that following reconstruction they yield only sinks or sources at the appropriate sites. In terms of number and polarity, some waves increased and others decreased proportional to the concomitant inputs in native multisynaptic LFPs. Interestingly, the processing also retrieved the initiation time for each wave, which can be used to discriminate

  4. Spatial distribution and polarization of {gamma}-rays generated via Compton backscattering in the Duke/OK-4 storage ring FEL

    Energy Technology Data Exchange (ETDEWEB)

    Park, S.H. E-mail: shpark@nanum.kaeri.re.kr; Litvinenko, V.N.; Tornow, W.; Montgomery, C

    2001-12-21

    Beams of nearly monochromatic {gamma}-rays are produced via intracavity Compton backscattering in the OK-4/Duke storage ring FEL, the high-intensity {gamma}-ray source (HI{gamma}S). Presently, HI{gamma}S generates {gamma}-ray beams with an energy tunable from 2 to 58 MeV and a maximum flux of 5x10{sup 7} {gamma}-rays per second. The {gamma}-rays are linearly polarized with a degree of polarization close to 100% (V.N. Litvinenko, et al., Predictions and expected performance for the VUV OK-5/Duke Storage Ring FEL with variable polarization, Nucl. Instr. and Meth. A, to be published in this proceeding) and they are collimated to pencil-like semi-monoenergetic beams with RMS energy spreads as low as 0.2%. The detailed theoretical and experimental studies of the {gamma}-ray beam quality were conducted during the last two years (S.H. Park, Thesis, Duke University, Durham, NC, USA, 2000). In this paper, we present the theoretical analysis and the experimental results on the spatial distribution and polarization of {gamma}-rays from the HI{gamma}S facility.

  5. Spatial distribution and polarization of gamma-rays generated via Compton backscattering in the Duke/OK-4 storage ring FEL

    CERN Document Server

    Park, S H; Tornow, W; Montgomery, C

    2001-01-01

    Beams of nearly monochromatic gamma-rays are produced via intracavity Compton backscattering in the OK-4/Duke storage ring FEL, the high-intensity gamma-ray source (HI gamma S). Presently, HI gamma S generates gamma-ray beams with an energy tunable from 2 to 58 MeV and a maximum flux of 5x10 sup 7 gamma-rays per second. The gamma-rays are linearly polarized with a degree of polarization close to 100% (V.N. Litvinenko, et al., Predictions and expected performance for the VUV OK-5/Duke Storage Ring FEL with variable polarization, Nucl. Instr. and Meth. A, to be published in this proceeding) and they are collimated to pencil-like semi-monoenergetic beams with RMS energy spreads as low as 0.2%. The detailed theoretical and experimental studies of the gamma-ray beam quality were conducted during the last two years (S.H. Park, Thesis, Duke University, Durham, NC, USA, 2000). In this paper, we present the theoretical analysis and the experimental results on the spatial distribution and polarization of gamma-rays fro...

  6. 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.

  7. Asymmetry of the cross section for the reaction. gamma. d. -->. pi. /sup 0/d with linearly polarized. gamma. rays at 500--700 MeV and at a c. m. angle theta(0 = 130/sup 0/

    Energy Technology Data Exchange (ETDEWEB)

    Adamyan, F.V.; Akopyan, G.G.; Vartapetyan, G.A.; Galumyan, P.I.; Grabskii, V.O.; Karapetyan, V.V.; Karapetyan, G.V.; Oktanyan, V.K.

    1984-06-25

    The asymmetry of the cross section (..sigma..) of the reaction ..gamma..d ..-->.. ..pi../sup 0/d induced by linearly polarized ..gamma.. rays has been measured at energies E..gamma.. = 500 MeV, E..gamma.. = 600, and E/sub ..gamma../ = 700 MeV at the c.m. angle theta(0 = 130/sup 0/. The results disagree with calculations in the impulse approximation. The results can be explained in a qualitative way by appealing to an /sup 3/F/sub 3/ (2.26-GeV) dibaryon resonance.

  8. Proposal for a source of polarized protons; Projet de source de protons polarises

    Energy Technology Data Exchange (ETDEWEB)

    Abragam, A.; Winter, J. M. [Commissariat a l' energie atomique et aux energies alternatives - CEA, Centre d' Etudes Nucleaires de Saclay, BP2, Gif-sur-Yvette (France)

    1959-07-01

    Proposal for a source of polarized protons based on the theory of adiabatic fast passage due to F. Bloch. Reprint of a paper published in 'Physical review letters', vol 1, n. 10, 15 Nov 1958, p. 374-375 [French] On propose une methode nouvelle pour la realisation d'une source de protons polarises basee sur la theorie du passage adiabatique de F. Bloch. Reproduction d'un article publie dans 'Physical review letters', vol 1, n. 10, 15 nov 1958, p. 374-375.

  9. External gamma radiation dose studies in the proposed uranium mining areas of Andhra Pradesh, India

    International Nuclear Information System (INIS)

    Reddy, P.; Reddy, K.; Reddy, C.; Reddy, K.

    2006-01-01

    Natural radiation sources contribute the largest component to the total effective dose received by the human population. Among these sources, natural background gamma radiation shares a noteworthy amount. The present study aims at the establishment of baseline environmental gamma radiation data in the environs of proposed uranium mining areas of Andhra Pradesh, India. To this end, a systematic study has been undertaken using Thermoluminescence (T.L.) dosimeters and G.M. (Geiger - Muller) tube based survey meter. These levels are estimated both indoors and outdoors in the study area covering about 23 villages surrounding the proposed mining sites. The estimated external gamma radiation levels (air kerma) varied from 0.605 to 4.39 mGy.y -1 . The mean indoor to outdoor radiation level ratio is found to be 1.1 ± 0.1. The estimated mean equivalent doses due to external background radiation in the villages of the study area range from 1.03 to 2.83 mSv.y -1 with a mean of 2.34 ± 0.39 mSv.y -1 . (authors)

  10. Radiative corrections to the beam spin asymmetry in photon electroproduction e polarized p {yields} ep{gamma}

    Energy Technology Data Exchange (ETDEWEB)

    Fonvieille, H.; Bensafa, I. [LPC-Clermont-Fd, Universite Blaise Pascal, F-63170 Aubiere Cedex (France)

    2006-11-15

    We have measured at MAMI the beam single spin asymmetry (SSA) in exclusive photon electroproduction (e polarized p {yields} ep{gamma}) with a longitudinally polarized beam, in the region of the {delta}(1232) resonance. In this document the value of the radiative correction to this asymmetry is obtained for our kinematics. Although the correction is expected to be very small and negligible, its value is needed as a confirmation and for the purpose of systematic error estimate. The parameter of kinematics are given as follows: four-momentum transfer of the virtual photon, Q{sup 2} = 0.35 GeV{sup 2}; total energy in the ({gamma}p) center of mass, W=1.190 GeV; polarization of the virtual photon, {epsilon}=0.48; azimuthal angle (lepton-hadron planes), {phi} = 220 angle; polar angle of Compton scattering in center of mass, {theta}{sub {gamma}}{sub {gamma}} in [0 angle, 40 angle]; incoming electron beam energy, E{sub e} = 0.88 GeV; scattered electron energy, E{sub 0}' = 0.40 GeV; polar angle of scattered electron {theta}{sub e} = 59.9 angle. The radiative correction is calculated by the radcorr code written by M. Vanderhaeghen, in a version adapted to beam spin asymmetries.In practice, the conclusions are twofold: - the asymmetry that was measured in the VCS channel does not need to be corrected for radiative effects, given the large statistical error bar attached to the experimental values (an asymmetry of 1-10 % with a statistical error bar of 3-4 %); - a systematic error {delta}SSA{sub syst} on the asymmetry will be considered, related to uncertainties in the calculation of the radiative correction (at least two of them have been mentioned here: the cross section model and the soft photon limit). To estimate this error a 100 % variation of the radiative correction was assumed. For the radiative correction itself the maximal value found was taken. Therefore one can take: {delta}SSA{sub syst} = {+-}2.7 x 10{sup -3}.

  11. Undulator-Based Production of Polarized Positrons, A Proposal for the 50-GeV Beam in the FFTB

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, G

    2004-03-25

    The full exploitation of the physics potential of future linear colliders such as the JLC, NLC, and TESLA will require the development of polarized positron beams. In the proposed scheme of Balakin and Mikhailichenko [1] a helical undulator is employed to generate photons of several MeV with circular polarization which are then converted in a relatively thin target to generate longitudinally polarized positrons. This experiment, E-166, proposes to test this scheme to determine whether such a technique can produce polarized positron beams of sufficient quality for use in future linear colliders. The experiment will install a meter-long, short-period, pulsed helical undulator in the Final Focus Test Beam (FFTB) at SLAC. A low-emittance 50-GeV electron beam passing through this undulator will generate circularly polarized photons with energies up to 10 MeV. These polarized photons are then converted to polarized positrons via pair production in thin targets. Titanium and tungsten targets, which are both candidates for use in linear colliders, will be tested. The experiment will measure the flux and polarization of the undulator photons, and the spectrum and polarization of the positrons produced in the conversion target, and compare the measurement results to simulations. Thus the proposed experiment directly tests for the first time the validity of the simulation programs used for the physics of polarized pair production in finite matter, in particular the effects of multiple scattering on polarization. Successful comparison of the experimental results to the simulations will lead to greater confidence in the proposed designs of polarized positrons sources for the next generation of linear colliders. This experiment requests six-weeks of time in the FFTB beam line: three weeks for installation and setup and three weeks of beam for data taking. A 50-GeV beam with about twice the SLC emittance at a repetition rate of 30 Hz is required.

  12. Undulator-Based Production of Polarized Positrons, A Proposal for the 50-GeV Beam in the FFTB

    Energy Technology Data Exchange (ETDEWEB)

    G. Alexander; P. Anthony; V. Bharadwaj; Yu.K. Batygin; T. Behnke; S. Berridge; G.R. Bower; W. Bugg; R. Carr; E. Chudakov; J.E. Clendenin; F.J. Decker; Yu. Efremenko; T. Fieguth; K. Flottmann; M. Fukuda; V. Gharibyan; T. Handler; T. Hirose; R.H. Iverson; Yu. Kamyshkov; H. Kolanoski; T. Lohse; Chang-guo Lu; K.T. McDonald; N. Meyners; R. Michaels; A.A. Mikhailichenko; K. Monig; G. Moortgat-Pick; M. Olson; T. Omori; D. Onoprienko; N. Pavel; R. Pitthan; M. Purohit; L. Rinolfi; K.P. Schuler; J.C. Sheppard; S. Spanier; A. Stahl; Z.M. Szalata; J. Turner; D. Walz; A. Weidemann; J. Weisend

    2003-06-01

    The full exploitation of the physics potential of future linear colliders such as the JLC, NLC, and TESLA will require the development of polarized positron beams. In the proposed scheme of Balakin and Mikhailichenko [1] a helical undulator is employed to generate photons of several MeV with circular polarization which are then converted in a relatively thin target to generate longitudinally polarized positrons. This experiment, E-166, proposes to test this scheme to determine whether such a technique can produce polarized positron beams of sufficient quality for use in future linear colliders. The experiment will install a meter-long, short-period, pulsed helical undulator in the Final Focus Test Beam (FFTB) at SLAC. A low-emittance 50-GeV electron beam passing through this undulator will generate circularly polarized photons with energies up to 10 MeV. These polarized photons are then converted to polarized positrons via pair production in thin targets. Titanium and tungsten targets, which are both candidates for use in linear colliders, will be tested. The experiment will measure the flux and polarization of the undulator photons, and the spectrum and polarization of the positrons produced in the conversion target, and compare the measurement results to simulations. Thus the proposed experiment directly tests for the first time the validity of the simulation programs used for the physics of polarized pair production in finite matter, in particular the effects of multiple scattering on polarization. Successful comparison of the experimental results to the simulations will lead to greater confidence in the proposed designs of polarized positrons sources for the next generation of linear colliders. This experiment requests six-weeks of time in the FFTB beam line: three weeks for installation and setup and three weeks of beam for data taking. A 50-GeV beam with about twice the SLC emittance at a repetition rate of 30 Hz is required.

  13. Application of FEL technique for constructing high-intensity, monochromatic, polarized gamma-sources at storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Saldin, E.L.; Schneidmiller, E.A.; Ulyanov, Yu.N. [Automatic Systems Corporation, Samara (Russian Federation)] [and others

    1995-12-31

    A possibility to construct high-intensity tunable monochromatic{gamma}-source at high energy storage rings is discussed. It is proposed to produce {gamma}-quanta by means of Compton backscattering of laser photons on electrons circulating in the storage. The laser light wavelength is chosen in such a way that after the scattering, the electron does not leave the separatrix. So as the probability of the scattering is rather small, energy oscillations are damped prior the next scattering. As a result, the proposed source can operate in {open_quotes}parasitic{close_quote} mode not interfering with the main mode of the storage ring operation. Analysis of parameters of existent storage rings (PETRA, ESRF, Spring-8, etc) shows that the laser light wavelength should be in infrared, {lambda}{approximately} 10 - 400 {mu}m, wavelength band. Installation at storage rings of tunable free-electron lasers with the peak and average output power {approximately} 10 MW and {approximately} 1 kW, respectively, will result in the intensity of the {gamma}-source up to {approximately} 10{sup 14}s{sup -1} with tunable {gamma}-quanta energy from several MeV up to several hundreds MeV. Such a {gamma}-source will reveal unique possibilities for precision investigations in nuclear physics.

  14. Precision gamma-ray polarimetry applied to studies of bremsstrahlung produced by polarized electrons

    Energy Technology Data Exchange (ETDEWEB)

    Kovtun, Oleksiy

    2015-12-16

    The thesis reports on the measurement of bremsstrahlung linear polarization produced in collisions of longitudinally and transversely polarized electrons with gold atoms. The experiment was performed at the Mainzer Microtron MAMI in the Institut fuer Kernphysik of Johannes Gutenberg-Universitaet Mainz, Germany. Spin-oriented electrons with 2.15 MeV kinetic energy collided with a thin golden target and produced bremsstrahlung. Linear polarization of the emitted photons was measured by means of Compton polarimetry applied to a segmented high-purity germanium detector. Experimental results reveal a strong correlation between the electron spin orientation and bremsstrahlung linear polarization. This indicates a dominant role of the electron spin in atomic-field bremsstrahlung and Coulomb scattering.

  15. Calibration of the Gamma-RAy Polarimeter Experiment (GRAPE) at a polarized hard X-ray beam

    International Nuclear Information System (INIS)

    Bloser, P.F.; Legere, J.S.; McConnell, M.L.; Macri, J.R.; Bancroft, C.M.; Connor, T.P.; Ryan, J.M.

    2009-01-01

    The Gamma-RAy Polarimeter Experiment (GRAPE) is a concept for an astronomical hard X-ray Compton polarimeter operating in the 50-500 keV energy band. The instrument has been optimized for wide-field polarization measurements of transient outbursts from energetic astrophysical objects such as gamma-ray bursts and solar flares. The GRAPE instrument is composed of identical modules, each of which consists of an array of scintillator elements read out by a multi-anode photomultiplier tube (MAPMT). Incident photons Compton scatter in plastic scintillator elements and are subsequently absorbed in inorganic scintillator elements; a net polarization signal is revealed by a characteristic asymmetry in the azimuthal scattering angles. We have constructed a prototype GRAPE module containing a single CsI(Na) calorimeter element, at the center of the MAPMT, surrounded by 60 plastic elements. The prototype has been combined with custom readout electronics and software to create a complete 'engineering model' of the GRAPE instrument. This engineering model has been calibrated using a nearly 100% polarized hard X-ray beam at the Advanced Photon Source at Argonne National Laboratory. We find modulation factors of 0.46±0.06 and 0.48±0.03 at 69.5 and 129.5 keV, respectively, in good agreement with Monte Carlo simulations. In this paper we present details of the beam test, data analysis, and simulations, and discuss the implications of our results for the further development of the GRAPE concept.

  16. VCS-SSA Mainz Experiment. Measurement of the beam spin asymmetry in (e polarized p {yields} ep{gamma}) and (e polarized p {yields} ep{pi}{sup 0}). Final analysis - MEMO I

    Energy Technology Data Exchange (ETDEWEB)

    Fonvieille, H.; Bensafa, I. [LPC-Clermont-Fd, Universite Blaise Pascal, F-63170 Aubiere Cedex (France)

    2006-02-15

    This note gives details on the final analysis of the VCS-SSA experiment in terms of Beam Spin Asymmetry. It summarizes the changes between the first and second pass analysis. Then the measured asymmetry is presented for both channels e polarized p {yields} ep{gamma} and e polarized p {yields} ep{pi}{sup 0} including systematic studies. The final experimental result is briefly compared to some model predictions. (authors)

  17. Measurement of proton polarization in the reaction. gamma. /ital p//r arrow//ital p/. pi. /sup 0/ at an angle theta/sup *//sub. pi. /sup 0//=80/degree/ in a linearly polarized photon beam

    Energy Technology Data Exchange (ETDEWEB)

    Avakyan, R. O.; Avakyan, E. O.; Avetisyan, A. E.; Aivazyan, R. B.; Arestakesyan, G. A.; Bagdasryan, A. S.; Vartapetyan, G. A.; Garibyan, Y. A.; Eganov, V. S.; Karapetyan, A. P.; and others

    1988-12-01

    Measurements are reported of the energy dependence of the /ital p//sub /ital xz// and /ital P//sub /ital y// components of the polarization vector of the recoil protons in the reaction ..gamma../ital p//r arrow//ital p/..pi../sup 0/ for a ..pi../sup 0/-meson production angle theta/sup *//sub ..pi../sup 0// =80/degree/ in the c.m.s. in the ..gamma..-ray energy range /ital E//sub ..gamma../=730--1066 MeV. The experimental data are compared with the results of various phenomenological analyses.

  18. Regulatory inspection of the egyptian gamma irradiator using a proposed inspection checklist

    International Nuclear Information System (INIS)

    Abdel-Ghani, A.H.

    2000-01-01

    Regulatory inspections are one of the most important elements of a regulatory programme. It shall be performed in all areas of the regulatory responsibility and during all phases of siting, design, construction, commissioning, operation, maintenance and decommissioning of an irradiator facility. The egyptian mega gamma irradiator operating since december 1979 has a Co-60 source of about 400 kilo curies and is used mainly for sterilization of medical supplies and pharmaceuticals and for preservation of some food stuffs. The constructor (Nordion international Inc.) recommended an extensive inspection programme. In accordance with the international and national (2.3) regulations as well as the licensing conditions, the competent authority (NCNSRC) shall perform regulatory inspections both announced and unannounced. In order to facilitate the inspection task and to harmonize the inspection reports a checklist for inspection is proposed which can be used also as an inspection report form

  19. Gamma-ray linear polarization measurements following heavy-ion bombardment of odd isotopes of Pd

    International Nuclear Information System (INIS)

    Kim, J.S.; Lee, Y.K.; Hardy, K.A.; Simms, P.C.; Grau, J.A.; Smith, G.J.; Rickey, F.A.

    1975-01-01

    γ-ray linear polarization measurements have been used to locate negative parity states in the even-odd isotopes 99 , 101 , 103 Pd. A Compton polarimeter based on two Ge(Li) coaxial detectors was used. Collective bands (I=11 - /2, 15 - /2, 19 - /2, . . .) bulit on 11 - /2 states were observed in 101 Pd and 103 Pd. Many negative parity states were also observed in 99 Pd, but they do not appear to be part of a similar collective band. These polarization measurements also confirm many angular momentum assignments which previously had been made using systematic arguments

  20. The circular polarization of gamma rays from heavy-ion reactions high above the Coulomb barrier

    International Nuclear Information System (INIS)

    Lauterbach, C.; Boer, J. de; Duennweber, W.; Graw, G.; Hering, W.; Puchta, H.; Trautmann, W.

    1978-01-01

    We have measured the circular polarization P of the γ radiation emitted in coincidence with the projectile-like fragments from the 100 MeV 16 O+ 27 Al, 58 Ni reactions at the Munich MP tandem accelerator and the 284 (303) Mev 40 Ar+Ag and 539 MeV 86 Kr+Ag reactions at the GSI UNILAC. (orig.) [de

  1. Polarization parameters. sigma. , T, and P for the reaction. gamma. p. -->. p. pi. /sup 0/ in the region of the first resonance

    Energy Technology Data Exchange (ETDEWEB)

    Belyaev, A.A.; Get' man, V.A.; Gorbenko, V.G.; Gushchin, V.A.; Derkach, A.Y.; Zhebrovskii, Y.V.; Karnaukhov, I.M.; Kolesnikov, L.Y.; Lukhanin, A.A.; Rubashkin, A.L.; Sorokin, P.V.; Sporov, E.A.; Telegin, Y.N.

    1982-03-01

    We report an experimental study of the ..sigma.., T, and P parameters of the cross section for the reaction ..gamma..p..-->..p..pi../sup 0/ for photon energies 300, 320, 350, 380, 400, 420 MeV in the range of pion emission angles 60--135/sup 0/ c.m.s. The technique of a double polarization experiment with use of linearly polarized photons and a polarized proton target is described. The experimental results are compared with the predictions of theoretical analyses.

  2. Observation of photon polarization in $B^\\pm \\to K^\\pm\\pi^\\mp\\pi^\\pm\\gamma$ decays

    CERN Multimedia

    Veneziano, G

    2014-01-01

    A study of the flavor-changing neutral current radiative $B^{\\pm} \\to K^{\\pm}\\pi^{\\mp}\\pi^{\\pm}\\gamma$ decays performed using data collected in proton-proton collisions with the LHCb detector at $7$ and $8\\,$TeV center-of-mass energies is presented. In this sample, corresponding to an integrated luminosity of $3\\,\\text{fb}^{-1}$, nearly $14\\,000$ signal events are reconstructed and selected, containing all possible intermediate resonances with a $K^{\\pm}\\pi^{\\mp}\\pi^{\\pm}$ final state in the $[1.1, 1.9]$\\,GeV/$c^{2}$ mass range. The distribution of the angle of the photon direction with respect to the plane defined by the final-state hadrons in their rest frame is studied in intervals of $K^{\\pm}\\pi^{\\mp}\\pi^{\\pm}$ mass and the asymmetry between the number of signal events found on each side of the plane is obtained. The first direct observation of the photon polarization in the $b \\to s\\gamma$ transition is reported with a significance of $5.2\\,\\sigma$.

  3. Asymmetry of the cross section of the reaction. gamma. n. --> pi. /sup -/p induced by linearly polarized photons with energies 0. 8--1. 75 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Adamyan, V.V.; Akopyan, G.G.; Vartapetyan, G.A.; Galumyan, P.I.; Grabskii, V.O.; Karapetyan, V.V.; Karapetyan, G.V.; Oktanyan, V.K.

    1985-10-25

    The asymmetry of the cross section ..sigma.. of the reaction ..gamma..n..--> pi../sup -/p induced by linearly polarized photons in the energy range 0.8--1.75 GeV and at c.m. angles of 45--90/sup 0/ is measured. The measurement results are consistent with the predictions of the existing phenomenological analyses.

  4. Fluorescence of the gamma, epsilon, and delta systems of nitric oxide - Polarization and use of calculated intensities for spectrometer calibration.

    Science.gov (United States)

    Poland, H. M.; Broida, H. P.

    1971-01-01

    Results of a study in which fluorescence of the gamma system of nitric oxide was obtained by excitation from both the 2144 A line of ionized cadmium and a continuum source. Individual rotational lines of the 2144 A excited fluorescence spectrum were found to be partially polarized and to have polarizations of differ ing sign. Measured relative vibrational band intensities from line and continuum excitation were compared to calculated Franck-Condon factors. Those Franck-Condon factors based on a single potential for the two spin states of the X super pi state agreed better with measured values than those based on separate potentials for the two spin states. Calculated intensities of the v prime = 3 progression were used to calibrate the instrument response in the wavelength region from 2000 to 2500 A and were checked with measured intensities of the v prime = 0.1, and 2 progressions. Fluorescence of the epsilon and delta bands obtained with continuum lamp excitation also were compared to calculated intensities.

  5. Differential cross section and recoil polarization measurements for the gamma p to K+ Lambda reaction using CLAS at Jefferson Lab

    Energy Technology Data Exchange (ETDEWEB)

    McCracken, Michael E. [Carnegie Mellon Univ., Pittsburgh, PA (United States)

    2010-02-01

    We present measurements of the differential cross section and Lambda recoil polarization for the gamma p to K+ Lambda reaction made using the CLAS detector at Jefferson Lab. These measurements cover the center-of-mass energy range from 1.62 to 2.84 GeV and a wide range of center-of-mass K+ production angles. Independent analyses were performed using the K+ p pi- and K+ p (missing pi -) final-state topologies; results from these analyses were found to exhibit good agreement. These differential cross section measurements show excellent agreement with previous CLAS and LEPS results and offer increased precision and a 300 MeV increase in energy coverage. The recoil polarization data agree well with previous results and offer a large increase in precision and a 500 MeV extension in energy range. The increased center-of-mass energy range that these data represent will allow for independent study of non-resonant K+ Lambda photoproduction mechanisms at all production angles.

  6. Measurement of the circular polarization of gamma radiation from heavy ion collisions

    International Nuclear Information System (INIS)

    Lauterbach, C.

    1981-01-01

    For the nuclear reactions 16 O + 27 Al, 16 O + 58 Ni, 16 O + 62 Ni, 40 Ar + sup(nat)Ag, 86 Kr + sup(nat)Ag, and 86 Kr + 197 Au at incident energies of about 7 MeV/nucleon the circular polarization of the #betta# radiation emitted by the reaction products was measured. The projectile - like reaction products were detected by a δE-E telescope at a fixed angle of 35 0 relative to the beam axis. It is shown that the sign of the scattering angle for the classical orbit of the reaction partners can be determined by the experimental detection of circularly polarized #betta#-radiation from the decay of the highly excited reaction products. In the performed experiments for the first time extensive polarization phenomena in deep inelastic reactions were observed. The dominance of negative scattering angles was verified for a large range of light and medium-heavy systems. The results are compared with the predictions of theoretical models in which statistical or quantum mechanical fluctuations of the dynamical quantities are regarded. (orig./HSI) [de

  7. Polarized Moessbauer transitions

    International Nuclear Information System (INIS)

    Barb, D.

    1975-01-01

    Theoretical aspects of the emission, absorption and scattering of polarized gamma rays are reviewed for a general case of combined magnetic and electric hyperfine interactions; various possibilities of obtaining polarized gamma sources are described and examples are given of the applications of Moessbauer spectroscopy with polarized gamma rays in solving problems of solid state physics. (A.K.)

  8. PhD Dissertation Proposal - Introduction to Dark Mix Concept: Gamma Measurements of Capsule Mixture

    Energy Technology Data Exchange (ETDEWEB)

    Meaney, Kevin Daniel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-10-06

    Presentation slides: Intro to Inertial Confinement Fusion; Types of Mixture in ICF capsules; Previous mixture experiments; Dark Mix Concept; Measuring Dark Mix with Gamma Cherenkov Detector; Dissertation Outline.

  9. 77 FR 62267 - Proposed Extension of Existing Information Collection; Gamma Radiation Surveys

    Science.gov (United States)

    2012-10-12

    ... debilitating occupational diseases. Natural sources include rocks, soils, and ground water. Gamma radiation..., electronic, mechanical, or other technological collection techniques or other forms of information technology...

  10. Proposal of a wide-band mirror polarizer of slow neutrons at a pulsed neutron source

    International Nuclear Information System (INIS)

    Nikitenko, Yu.V.; Ostanevich, Yu.M.

    1992-01-01

    The new type wide-band mirror-based neutron polarizer to be operated at a pulsed neutron source is suggested. The idea is to use a movable polarizing mirror system, which, be the incoming beam monochromatized by the time-of-flight, would allow one to tune glancing angles in time so, that the total reflection condition is always fulfilled only for one of the two neutron spin eigenstates. Estimates show, that with the pulsed reactor IBR-2 such polarizer allows one to build a small-angle neutron scattering instrument capable to effectively use the wave-length band from 2 to 15 A. 9 refs.; 1 fig

  11. A proposal for spreading and commercializing the (n, gamma) 99Tc generator

    International Nuclear Information System (INIS)

    Yoshida, Kosuke; Hishinuma, Yukio; Tatenuma, Katsuyoshi

    2006-01-01

    A practicability of 99m Tc generator based on (n, gamma) method using PZC (Poly Zirconium Compound), a Mo adsorbent with a high adsorption efficiency, has been studied by the FNCA member countries as a part of the FNCA activities; three research collaboration projects, Technetium Generator Project (TCG), Neutron Activation Analysis Project (NAA) and Neutron Spreading Project (NS) have been set up in order to achieve the significant results of the research reactor use among Asian countries. As a result of the collaboration research, practical data on the 99m Tc elution and 99 Mo breakthrough has recently been obtained by using the new 99m Tc generator based on (n, gamma) method using PZC (indicate 'PZC- 99m Tc generator' as follows). Even though unexpected amount of 99 Mo breakthrough accompanied with the 99m Tc elution treatment were currently occurred, the problem has been solved by subsequently adding an alumina column underneath the generator column containing PZC. In accordance with the realization of the practical PZC- 99m Tc generator, an administering tests to the mice with labeled compound of 99m Tc generated by PZC method have already been started by BATAN, a loading machine to simplify the process of the 99 Mo adsorption to PZC and the 99 Mo-PZC packing to a generator column has been fabricated in BATAN's hot cell to realize a mass production of PZC- 99m Tc generator, and moreover the Japanese and Indonesian patents pertaining to the production process and the loading machine of PZC- 99m Tc generator have been applied with joint application of BATAN and KAKEN Co. By the current collaboration approaches mentioned above, it is clear that the Technetium Generator Project of FNCA is now reaching to a phase where the aims of the project shall be turned from establishment of the practical PZC- 99m C generator to establishment of the delivery system of PZC- 99m Tc generator to put them into commercial use. In this paper, a practical application of the PZC- 99m

  12. Fractal structure of hadrons in processes with polarized protons at SPD NICA (proposal for experiment)

    International Nuclear Information System (INIS)

    Tokarev, M.V.; Aparin, A.A.; Zborovsky, I.

    2014-01-01

    The concept of z-scaling previously developed for analysis of inclusive reactions in proton-proton collisions is applied for description of processes with polarized protons at the planned Spin Physics Detector NICA in Dubna. A hypothesis of self-similarity and fractality of the proton spin structure is discussed. The possibilities to extract information on spin-dependent fractal dimensions of hadrons and fragmentation process from asymmetries and coefficients of polarization transfer are justified. The double longitudinal spin asymmetry A LL of π 0 -meson production and the coefficient of the polarization transfer D LL of Λ hyperon production in proton-proton collisions measured at RHIC are analyzed in the framework of z-scaling. The spin-dependent fractal dimensions of proton and fragmentation process with polarized Λ hyperon are estimated. A study of the spin-dependent constituent energy loss as a function of transverse momentum of the inclusive hadron and collision energy is suggested.

  13. Inverse Compton gamma-rays from pulsars

    International Nuclear Information System (INIS)

    Morini, M.

    1983-01-01

    A model is proposed for pulsar optical and gamma-ray emission where relativistic electrons beams: (i) scatter the blackbody photons from the polar cap surface giving inverse Compton gamma-rays and (ii) produce synchrotron optical photons in the light cylinder region which are then inverse Compton scattered giving other gamma-rays. The model is applied to the Vela pulsar, explaining the first gamma-ray pulse by inverse Compton scattering of synchrotron photons near the light cylinder and the second gamma-ray pulse partly by inverse Compton scattering of synchrotron photons and partly by inverse Compton scattering of the thermal blackbody photons near the star surface. (author)

  14. Cross section asymmetry of deuteron photodesintegration reaction with polarized gamma quanta

    International Nuclear Information System (INIS)

    Gorbenko, V.G.; Zhebrovskij, Yu.V.; Kolesnikov, L.Ya.; Rubashkin, A.L.; Sorokin, P.V.

    1982-01-01

    The parameters of the reaction cross section asymmetry are determined to investigate the γ+d → n+p reaction. The measurements are exercised on a beam of linearly polarized photons of a linear 2 GeV electron accelerator by means of two magnetic spectrometers in the Esub(γ)=80-600 MeV energy range for 75-105 deg angles of proton escape in scm. The flowsheet of an experimental facility is presented. Technique of the experiment execution is presented. The obtained values of the cross section asymmetry parameter are presented in the table form for the 75, 90, 105, 120, 135, 150 deg angles. Calculation of the differential cross sections is carried out in pulse approximation. Energy Dependence and angutar distribUtions of the cross section asymmetry parameter of the investigated reaction are presented graphically. The obtained results are compared with the present experimental and theoretical data at 80 and 300 MeV photon energy. The comparison has revealed that none of the calculation methods is more preferable as well as no simple conclusion can be made on the existence of dibarin resonances

  15. Spin and parity assignments to dipole excitations of the odd-mass nucleus {sup 207}Pb from nuclear resonance fluorescence experiments with linearly-polarized {gamma}-ray beams

    Energy Technology Data Exchange (ETDEWEB)

    Pietralla, N; Fritzsche, M; Savran, D [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Li, T C [Nuclear Structure Laboratory, SUNY at Stony Brook, Stony Brook, NY 11794-3800 (United States); Ahmed, M W; Tonchev, A P; Tornow, W; Weller, H R [Triangle Universities Nuclear Laboratory (TUNL), Duke University, Durham, NC 27708 (United States); Werner, V, E-mail: pietralla@ikp.tu-darmstadt.d [A.W. Wright Nuclear Structure Laboratory (WNSL), Yale University, New Haven, CT (United States)

    2010-01-01

    Pb({gamma}-vector ,{gamma}') photon scattering reactions were studied [1] with the nearly monochromatic, linearly polarized photon beams at the High Intensity {gamma}-ray Source (HI{gamma}S) at the DFELL. Azimuthal scattering intensity asymmetries measured with respect to the polarization plane of the beam have been used for the first time to assign both the spin and parity quantum numbers of dipole excited states of {sup 206,207,208}Pb at excitation energies in the vicinity of 5.5 MeV. Evidence for dominant particle-core coupling is deduced from these results along with information on excitation energies and electromagnetic transition matrix elements.

  16. Proposal of a wide-band mirror polarizer of slow neutrons at a pulsed neutron source

    International Nuclear Information System (INIS)

    Nikitenko, Yu.V.; Ostanevich, Yu.M.

    1993-01-01

    The new type of wide-band mirror-based neutron polarizer, which is to be operated at a pulsed neutron source, is suggested. The idea is to use a movable polarizing mirror system, which, with the incoming beam monochromatized by the time-of-flight, would allow one to tune glancing angles in time so that the total reflection condition is always fulfilled only for one of the two neutron spin eigenstates. Estimates show that with the pulsed reactor IBR-2 such a polarizer allows one to build a small angle neutron scattering instrument capable of effectively using the wavelength band from 2 A with a rather high luminosity (time-averaged flux at sample position being up to 10 7 n/s/cm -2 ). (orig.)

  17. Fractal structure of hadrons in processes with polarized protons at SPD NICA (Proposal for experiment)

    Czech Academy of Sciences Publication Activity Database

    Tokarev, M. V.; Zborovský, Imrich; Aparin, A. A.

    2015-01-01

    Roč. 12, č. 1 (2015), s. 48-58 ISSN 1547-4771 R&D Projects: GA MŠk LG14004 Institutional support: RVO:61389005 Keywords : asymmetry * high energy * polarization * proton-proton collisions * Self-similarity Subject RIV: BE - Theoretical Physics

  18. X and gamma ray backgroud observations in Antarctic

    International Nuclear Information System (INIS)

    Jayanthi, U.B.

    1988-01-01

    Atmospheric X amd gamma rays are products of complex electromagnetic interation between charged particles and atmospheric constituents. The latitudinal dependence of the cosmic rays secondaries, auroral and South Atlantic Anomaly phenomena produce flux variations, especially the later temporal flux variations. We propose to discuss these variations in relevance to balloon flight observations of X and gamma ray atmospheric background at polar latitudes. (author) [pt

  19. Influence of Neutral Currents on Electron and Gamma Polarizations in the Process e+N→e′+N+γ

    International Nuclear Information System (INIS)

    Ousmane Manga, Adamou; Moussa, Aboubacar; Aboubacar, Almoustapha; Samsonenko, N. V.

    2014-01-01

    The differential cross section of electron inelastic scattering by nuclei followed by γ radiation is calculated using the multipole decomposition of the hadronic currents and by taking into account the longitudinal polarization of the initial electron and the circular polarization of the γ radiation. We performed the analysis of the angular and energy dependence of the degree of electron and photon polarization which can yield information on values of weak neutral currents parameters

  20. Perpendicularity among the linear polarization directions of {gamma} radiations coming from the positron-electron annihilation: entanglement or conservation law; Perpendicularidade entre as direcoes de polarizacao linear das radiacoes-{gamma} originarias do processo de aniquilacao positron-eletron: emaranhamento ou lei de conservacao

    Energy Technology Data Exchange (ETDEWEB)

    Cavalcante, Jose T.P.D.; Silva, Paulo R.J.; Saitovitch, Henrique [Centro Brasileiro de Pesquisas Fisicas (CBPF/MCT), Rio de Janeiro, RJ (Brazil). Lab. de Correlacao Angular

    2010-07-01

    The results of the experiments presented in this paper, concludes that the number of coincidences among the R{gamma} polarized by the EC-method is bigger with the detectors perpendicularly positioned (90 deg) than the parallel (0 deg). It can also observed that the R{gamma} source used presents, close to the 511 keV, another R{gamma} source with more problematic shielding

  1. Proposed data acquisition system for an associated particle neutron generator and a LYSO gamma detector

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Kwang Pyo; Sim, Cheul Muu; Em, V. T.; Lee, Seung Wook; Kim, Young Jin [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Park, Seong Yong; Park, Jin; Kim, Hee Jung [Kyungwon Enterprise, Seoul (Korea, Republic of)

    2005-07-01

    A data acquisition system has been designed that deals with essentially two signals: a sharp timing pulse (with a width of roughly 20 nanoseconds) from a Hamamatsu H6568 square photomultiplier tube utilizing a 16-pixel ZnO(Ga) phosphor-coated alpha particle detector, and a long energy pulse (with a falltime of roughly 200 microseconds) from a LYSO detector designed for extreme precision in measuring the energy of gamma rays. These two detectors have been selected because they exhibit ideal characteristics for the ultimate goal of this system: detection and identification of drugs, explosives, and chemical warfare agents at a comparably very high rate of speed while maintaining reliable decision-making capacity. The entire data acquisition Will be designed and each component Will be specified with a commercially-available electronic module utilizing a VME bus or high speed CAMAC.

  2. Proposal of a calibration protocol of gamma chambers for estimation of the radionuclides incorporation in emergency situations

    International Nuclear Information System (INIS)

    Dantas, B.M.; Lucena, E.; Dantas, A.L.A.; Araujo, F.; Melo, D.; Teran, M.; Paolino, A.; Hermida, J.C.; Rojo, A.; Puerta, J.A.; Morales, J.; Lopez B, G.M.; Alfaro, M.; Ruiz, M.A.; Videla, R.; Pinones, O.; Gonzalez, S.; Navarro, T.; Cruz S, R.

    2006-01-01

    In the last years in several countries has come increasing the concern with the possibility of accidents related to the transport and manipulation of open sources used in nuclear medicine. This carried out to the search of alternative methods for the monitoring of workers and individuals of the public exposed to the radionuclides incorporation like 131 I, 201 Tl, 153 Sm among others. One of the options to assist the demand for monitoring of the radionuclides incorporation is the use of gamma chambers that are medical diagnostic equipment available in the own centers of nuclear medicine. The gamma chambers are used to obtain images of patient to which are administered a radionuclide of well-known activity with diagnostic purposes. These equipment have among its components elements that spectrometric systems like those used in the evaluation of the internal incorporation for direct measurements, reason why besides its use for diagnosis by image they can be gauged with anthropomorphic simulators and also with punctual sources for the quantification of the radionuclides activity, distributed homogeneously in the human body or located in specific organs. This work presents the development of a calibration protocol of gamma chambers for the in vivo determination of radionuclides and it proposes the implementation of the protocol in centers of nuclear medicine of the 9 countries participants of the project OAS-ARCAL-RLA/9/049-LXXVIII - Harmonization of procedures of internal dosimetry (Argentina, Brazil, Colombia, Cuba, Chile, Mexico, Peru, Uruguay and Spain). The protocol is the base to establish an integrated net to attend in the response to emergencies using nuclear medicine centers of public hospitals of the region. The proposal is an additional alternative for the monitoring of people in emergency situations where it is possible and feasible the use of the gamma chambers. This would avoid the person's transport with incorporation suspicion for a conventional whole

  3. Measurement of polarization observables in the reaction {gamma}p{yields} p{pi}{sup 0}{pi}{sup 0} using linearly polarized photons with the CBELSA/TAPS experiment

    Energy Technology Data Exchange (ETDEWEB)

    Sokhoyan, Vahe

    2012-07-27

    The spectrum and the properties of baryon resonances can be studied using photons with energies appropriate to excite baryonic states. Double meson photoproduction allows access to cascading resonance decays via other excited states. Also, at higher energies the importance of the double meson photoproduction increases due to higher cross-sections in comparison to single meson photoproduction. To study baryon resonances, the measurement of polarization observables as well as the measurement of differential cross-sections plays a very important role. In this work the three-body polarization observables I{sup s}, I{sup c} and the respective twobody asymmetry {Sigma} were measured for the reaction {gamma}p {yields} p{pi}{sup 0}{pi}{sup 0} in an incoming photon energy range of E{sub {gamma}} = 970 - 1650 MeV. The data were acquired with the CBELSA/TAPS experiment located at the ELSA accelerator in Bonn, using a linearly polarized photon beam impinging on a liquid hydrogen target. The observables I{sup s} and I{sup c} which occur in two-meson final states are measured for the first time in the reaction {gamma}p {yields} p{pi}{sup 0}{pi}{sup 0}. The corresponding two-body asymmetry {Sigma} is measured in an extended energy range in comparison to already existing data. A comparison with theoretical models shows that the polarization observables provide valuable input to study resonance contributions and their decay modes. The D{sub 33}(1700) {yields} {Delta}{pi} decay is studied based on the comparison of the Bonn-Gatchina Partial Wave Analysis (PWA) predictions with the data. Furthermore, a comparison of the data with the Bonn-Gatchina PWA and the Fix isobar model predictions allows to distinguish between these two models. Additionally, band-like structures and peaks are observed in the mass ranges of {Delta}(1232), D{sub 13}(1520), F{sub 15}(1680), f{sub 0}(980) and f{sub 2}(1270) in the according Dalitz plots and invariant mass distributions. The contributions of these

  4. Polarized γ source based on Compton backscattering in a laser cavity

    Directory of Open Access Journals (Sweden)

    V. Yakimenko

    2006-09-01

    Full Text Available We propose a novel gamma source suitable for generating a polarized positron beam for the next generation of electron-positron colliders, such as the International Linear Collider (ILC, and the Compact Linear Collider (CLIC. This 30-MeV polarized gamma source is based on Compton scattering inside a picosecond CO_{2} laser cavity generated from electron bunches produced by a 4-GeV linac. We identified and experimentally verified the optimum conditions for obtaining at least one gamma photon per electron. After multiplication at several consecutive interaction points, the circularly polarized gamma rays are stopped on a target, thereby creating copious numbers of polarized positrons. We address the practicality of having an intracavity Compton-polarized positron source as the injector for these new colliders.

  5. Oriented Polar Molecules in a Solid Inert-Gas Matrix: A Proposed Method for Measuring the Electric Dipole Moment of the Electron

    Directory of Open Access Journals (Sweden)

    A. C. Vutha

    2018-01-01

    Full Text Available We propose a very sensitive method for measuring the electric dipole moment of the electron using polar molecules embedded in a cryogenic solid matrix of inert-gas atoms. The polar molecules can be oriented in the z ^ -direction by an applied electric field, as has recently been demonstrated by Park et al. The trapped molecules are prepared into a state that has its electron spin perpendicular to z ^ , and a magnetic field along z ^ causes precession of this spin. An electron electric dipole moment d e would affect this precession due to the up to 100 GV/cm effective electric field produced by the polar molecule. The large number of polar molecules that can be embedded in a matrix, along with the expected long coherence times for the precession, allows for the possibility of measuring d e to an accuracy that surpasses current measurements by many orders of magnitude. Because the matrix can inhibit molecular rotations and lock the orientation of the polar molecules, it may not be necessary to have an electric field present during the precession. The proposed technique can be applied using a variety of polar molecules and inert gases, which, along with other experimental variables, should allow for careful study of systematic uncertainties in the measurement.

  6. Oriented Polar Molecules in a Solid Inert-Gas Matrix: A Proposed Method for Measuring the Electric Dipole Moment of the Electron

    Science.gov (United States)

    Vutha, A.; Horbatsch, M.; Hessels, E.

    2018-01-01

    We propose a very sensitive method for measuring the electric dipole moment of the electron using polar molecules embedded in a cryogenic solid matrix of inert-gas atoms. The polar molecules can be oriented in the $\\hat{\\rm{z}}$ direction by an applied electric field, as has recently been demonstrated by Park, et al. [Angewandte Chemie {\\bf 129}, 1066 (2017)]. The trapped molecules are prepared into a state which has its electron spin perpendicular to $\\hat{\\rm{z}}$, and a magnetic field along $\\hat{\\rm{z}}$ causes precession of this spin. An electron electric dipole moment $d_e$ would affect this precession due to the up to 100~GV/cm effective electric field produced by the polar molecule. The large number of polar molecules that can be embedded in a matrix, along with the expected long coherence times for the precession, allows for the possibility of measuring $d_e$ to an accuracy that surpasses current measurements by many orders of magnitude. Because the matrix can inhibit molecular rotations and lock the orientation of the polar molecules, it may not be necessary to have an electric field present during the precession. The proposed technique can be applied using a variety of polar molecules and inert gases, which, along with other experimental variables, should allow for careful study of systematic uncertainties in the measurement.

  7. Gamma-ray lasers or grasers

    International Nuclear Information System (INIS)

    Wilson, G.V.H.; George, E.P.; Hora, H.

    1976-01-01

    A method is described for controlling the emission and direction of gamma rays from excited nuclei contained in a sample source of suitable geometry having its major axis parallel to the proposed direction of gamma ray emission, comprising subjecting said sample source to thermal or dynamic polarization at temperatures approaching absolute zero in the presence of a strong magnetic field, and when a pulse of coherent gamma radiation is required along said major axis rotating the active nuclei through 90 0 by employing a short pulse of radio frequency oscillations in an auxilliary coil around the sample source

  8. Polarized proton capture reaction /sup 7/Li(p,. gamma. )/sup 8/Be in the energy range from 380 to 960 keV

    Energy Technology Data Exchange (ETDEWEB)

    Ulbricht, J; Arnold, W; Berg, H; Huttel, E; Krause, H H; Clausnitzer, G [Giessen Univ. (Germany, F.R.). Abt. Grossgeraete (Angewandte Kernphysik)

    1977-09-05

    The polarized proton capture in /sup 7/Li was used to study the reaction mechanism and to obtain spectroscopic information on the /sup 8/Be nucleus. Gamma-ray angular distributions of the analyzing power were measured as a function of proton energy from Esub(p) = 380-960 keV with three Ge(Li) detectors simultaneously. The excitation functions of the cross section and the analyzing power are strongly energy dependent. The data were analyzed unambiguously and represented by three R-matrix elements, two M1 and one E1. The energy dependence of the two M1 matrix elements agrees with the well-known two 1/sup +/ resonances at Esub(x) = 17.642 and 18.157 MeV. The energy dependence of the E1 matrix element shows a smooth background presumably caused by a direct-capture mechanism, and furthermore, a resonant contribution, which is a significant suggestion of a new 1/sup -/ state in the /sup 8/Be system at Esub(x) = 17.70 MeV with a width of GAMMAsub(p) = 180 keV.

  9. Analysis of proposed gamma-ray detection system for the monitoring of core water inventory in a pressurized water reactor

    International Nuclear Information System (INIS)

    Markoff, D.M.

    1987-12-01

    An initial study has been performed of the feasibility of employing an axial array of gamma detectors located outside the pressure vessel to monitor the coolant in a PWR. A one-dimensional transport analysis model is developed for the LOFT research reactor and for a mock-PWR geometry. The gamma detector response to coolant voiding in the core and downcomer has been determined for both geometries. The effects of various conditions (for example, time after shutdown, materials in the transport path, and the relative void fraction in different water regions) on the detector response are studied. The calculational results have been validated by a favorable comparison with LOFT experimental data. Within the limitations and approximations considered in the analysis, the results indicate that the gamma-ray detection scheme is able to unambiguously respond to changes in the coolant inventory within any vessel water region

  10. Proposal for fabrication-tolerant SOI polarization splitter-rotator based on cascaded MMI couplers and an assisted bi-level taper.

    Science.gov (United States)

    Wang, Jing; Qi, Minghao; Xuan, Yi; Huang, Haiyang; Li, You; Li, Ming; Chen, Xin; Jia, Qi; Sheng, Zhen; Wu, Aimin; Li, Wei; Wang, Xi; Zou, Shichang; Gan, Fuwan

    2014-11-17

    A novel silicon-on-insulator (SOI) polarization splitter-rotator (PSR) with a large fabrication tolerance is proposed based on cascaded multimode interference (MMI) couplers and an assisted mode-evolution taper. The tapers are designed to adiabatically convert the input TM(0) mode into the TE(1) mode, which will output as the TE(0) mode after processed by the subsequent MMI mode converter, 90-degree phase shifter (PS) and MMI 3 dB coupler. The numerical simulation results show that the proposed device has a silicon photonics technology.

  11. Ground tests with prototype of CeBr{sub 3} active gamma ray spectrometer proposed for future venus surface missions

    Energy Technology Data Exchange (ETDEWEB)

    Litvak, M.L., E-mail: litvak@mx.iki.rssi.ru [Space Research Institute, RAS, Moscow 117997 (Russian Federation); Sanin, A.B.; Golovin, D.V. [Space Research Institute, RAS, Moscow 117997 (Russian Federation); Jun, I. [Jet Propulsion Laboratory, Pasadena, CA (United States); Mitrofanov, I.G. [Space Research Institute, RAS, Moscow 117997 (Russian Federation); Shvetsov, V.N.; Timoshenko, G.N. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Vostrukhin, A.A. [Space Research Institute, RAS, Moscow 117997 (Russian Federation)

    2017-03-11

    The results of a series of ground tests with a prototype of an active gamma-ray spectrometer based on a new generation of scintillation crystal (CeBr{sub 3}) are presented together with a consideration to its applicability to future Venus landing missions. We evaluated the instrument's capability to distinguish the subsurface elemental composition of primary rock forming elements such as O, Na, Mg, Al, Si, K and Fe. Our study uses heritage from previous ground and field tests and applies to the analysis of gamma lines from activation reaction products generated by a pulsed neutron generator. We have estimated that the expected accuracies achieved in this approach could be as high as 1–10% for the particular chemical element being studied.

  12. Moment analysis of hadronic vacuum polarization. Proposal for a lattice QCD evaluation of gμ - 2

    Science.gov (United States)

    de Rafael, Eduardo

    2014-09-01

    I suggest a new approach to the determination of the hadronic vacuum polarization (HVP) contribution to the anomalous magnetic moment of the muon aμHVP in lattice QCD. It is based on properties of the Mellin transform of the hadronic spectral function and their relation to the HVP self-energy in the Euclidean. I show how aμHVP is very well approximated by a few moments associated to this Mellin transform and how these moments can be evaluated in lattice QCD, providing thus a series of tests when compared with the corresponding determinations using experimental data.

  13. Proposal of a broadband, polarization-insensitive and high-efficiency hot-carrier schottky photodetector integrated with a plasmonic silicon ridge waveguide

    International Nuclear Information System (INIS)

    Yang, Liu; Kou, Pengfei; Shen, Jianqi; Lee, El Hang; He, Sailing

    2015-01-01

    We propose a broadband, polarization-insensitive and high-efficiency plasmonic Schottky diode for detection of sub-bandgap photons in the optical communication wavelength range through internal photoemission (IPE). The distinctive features of this design are that it has a gold film covering both the top and the sidewalls of a dielectric silicon ridge waveguide with the Schottky contact formed at the gold–silicon interface and the sidewall coverage of gold can be easily tuned by an insulating layer. An extensive physical model on IPE of hot carriers is presented in detail and is applied to calculate and examine the performance of this detector. In comparison with a diode having only the top gold contact, the polarization sensitivity of the responsivity is greatly minimized in our photodetector with gold film covering both the top and the sidewall. Much higher responsivities for both polarizations are also achieved over a broad wavelength range of 1.2–1.6 μm. Moreover, the Schottky contact is only 4 μm long, leading to a very small dark current. Our design is very promising for practical applications in high-density silicon photonic integration. (paper)

  14. Proposal of a calibration protocol of gamma chambers for estimation of the radionuclides incorporation in emergency situations; Propuesta de un protocolo de calibracion de camaras gamma para estimacion de la incorporacion de radionucleidos en situaciones de emergencia

    Energy Technology Data Exchange (ETDEWEB)

    Dantas, B.M.; Lucena, E.; Dantas, A.L.A.; Araujo, F.; Melo, D. [Instituto de Radioprotecao e Dosimetria, Rio de Janeiro Brasil (Brazil); Teran, M.; Paolino, A. [Facultad de Quimica, Montevideo (Uruguay); Hermida, J.C. [Hospital de Clinicas, Facultad de Medicina, Montevideo (Uruguay); Rojo, A. [Autoridad Regulatoria Nuclear, Buenos Aires (Argentina); Puerta, J.A.; Morales, J. [Universidad Nacional de Colombia, Medellin (Colombia); Lopez B, G.M. [Centro de Proteccion e Higiene de las Radiaciones, Ciudad de la Habana (Cuba); Alfaro, M.; Ruiz, M.A. [Instituto Nacional de Investigaciones Nucleares (Mexico); Videla, R.; Pinones, O. [Comision Chilena de Energia Nuclear, Santiago (Chile); Gonzalez, S. [Instituto Peruano de Energia Nuclear, Lima (Peru); Navarro, T. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Madrid (Spain); Cruz S, R. [International Atomic Energy Agency, Vienna (Australia)

    2006-07-01

    In the last years in several countries has come increasing the concern with the possibility of accidents related to the transport and manipulation of open sources used in nuclear medicine. This carried out to the search of alternative methods for the monitoring of workers and individuals of the public exposed to the radionuclides incorporation like {sup 131} I, {sup 201} Tl, {sup 153} Sm among others. One of the options to assist the demand for monitoring of the radionuclides incorporation is the use of gamma chambers that are medical diagnostic equipment available in the own centers of nuclear medicine. The gamma chambers are used to obtain images of patient to which are administered a radionuclide of well-known activity with diagnostic purposes. These equipment have among its components elements that spectrometric systems like those used in the evaluation of the internal incorporation for direct measurements, reason why besides its use for diagnosis by image they can be gauged with anthropomorphic simulators and also with punctual sources for the quantification of the radionuclides activity, distributed homogeneously in the human body or located in specific organs. This work presents the development of a calibration protocol of gamma chambers for the in vivo determination of radionuclides and it proposes the implementation of the protocol in centers of nuclear medicine of the 9 countries participants of the project OAS-ARCAL-RLA/9/049-LXXVIII - Harmonization of procedures of internal dosimetry (Argentina, Brazil, Colombia, Cuba, Chile, Mexico, Peru, Uruguay and Spain). The protocol is the base to establish an integrated net to attend in the response to emergencies using nuclear medicine centers of public hospitals of the region. The proposal is an additional alternative for the monitoring of people in emergency situations where it is possible and feasible the use of the gamma chambers. This would avoid the person's transport with incorporation suspicion for

  15. Background gamma radiation monitoring of three clusters of villages surrounding Mohuldih, Banduhurang and Bagjata villages, the proposed uranium mining areas in Singhbhum, Jharkhand

    International Nuclear Information System (INIS)

    Chougaonkar, M.P.; Puranik, V.D.; Singh, Prashant

    2008-01-01

    Generation of power is a fundamental catalyst to the social and economic development of a country. India needs more power in order to have a strong industrial base and for infrastructure development. With this in view, there has been an emphasis on nuclear power as an alternative source in the field of electricity generation as the nuclear power can be an effective tool in reducing stress on the environment. The Singhbhum district in the state of Jharkhand in India has been known to have deposits of uranium and uranium mines like Jaduguda, Narwapahar, Bhatin etc have been operating in the region. With the increased requirement of electricity and hence suitable fuel, few more sites are proposed to mine uranium in the region. The sites proposed are near the villages of Mohuldih, Banduhurang and Bagjata and are proposed to be open cast mines. These areas of Singhbhum are not economically advanced areas. By and large, the population is poor and there are existing problems like malnutrition and poor health. The activities of mining and the associated developments in the region are expected to improve the economic condition of the residents either through direct employment in the mining facilities, or by indirect gains due to infrastructural developments in the region. In order to assess the impact of the mining operations on the environment and the population as well, it is necessary that the pre-operational survey be carried out in the regions in question. As is the practice, a complete pre-operational survey of the physical, chemical and environmental parameters has been carried out in the region. Background gamma radiation survey was also carried out, using the thermo luminescent dosimetry technique, to obtain the preoperational levels prevalent in the regions. This paper gives the results of the baseline background gamma radiation survey in the region. It was observed that the general gamma background levels of the areas, as measured using TLDs, was 1.36 ± 0.41 m

  16. PPAR-gamma activation is associated with reduced liver ischemia-reperfusion injury and altered tissue-resident macrophages polarization in a mouse model.

    Science.gov (United States)

    Linares, Ivan; Farrokhi, Kaveh; Echeverri, Juan; Kaths, Johan Moritz; Kollmann, Dagmar; Hamar, Matyas; Urbanellis, Peter; Ganesh, Sujani; Adeyi, Oyedele A; Yip, Paul; Selzner, Markus; Selzner, Nazia

    2018-01-01

    PPAR-gamma (γ) is highly expressed in macrophages and its activation affects their polarization. The effect of PPAR-γ activation on Kupffer cells (KCs) and liver ischemia-reperfusion injury (IRI) has not yet been evaluated. We investigated the effect of PPAR-γ activation on KC-polarization and IRI. Seventy percent (70%) liver ischemia was induced for 60mins. PPAR-γ-agonist or vehicle was administrated before reperfusion. PPAR-γ-antagonist was used to block PPAR-γ activation. Liver injury, necrosis, and apoptosis were assessed post-reperfusion. Flow-cytometry determined KC-phenotypes (pro-inflammatory Nitric Oxide +, anti-inflammatory CD206+ and anti-inflammatory IL-10+). Liver injury assessed by serum AST was significantly decreased in PPAR-γ-agonist versus control group at all time points post reperfusion (1hr: 3092±105 vs 4469±551; p = 0.042; 6hr: 7041±1160 vs 12193±1143; p = 0.015; 12hr: 5746±328 vs 8608±1259; p = 0.049). Furthermore, liver apoptosis measured by TUNEL-staining was significantly reduced in PPAR-γ-agonist versus control group post reperfusion (1hr:2.46±0.49 vs 6.90±0.85%;p = 0.001; 6hr:26.40±2.93 vs 50.13±8.29%; p = 0.048). H&E staining demonstrated less necrosis in PPAR-γ-agonist versus control group (24hr:26.66±4.78 vs 45.62±4.57%; p = 0.032). The percentage of pro-inflammatory NO+ KCs was significantly lower at all post reperfusion time points in the PPAR-γ-agonist versus control group (1hr:28.49±4.99 vs 53.54±9.15%; p = 0.040; 6hr:5.51±0.54 vs 31.12±9.58%; p = 0.009; 24hr:4.15±1.50 vs 17.10±4.77%; p = 0.043). In contrast, percentage of anti-inflammatory CD206+ KCs was significantly higher in PPAR-γ-agonist versus control group prior to IRI (8.62±0.96 vs 4.88 ±0.50%; p = 0.04). Administration of PPAR-γ-antagonist reversed the beneficial effects on AST, apoptosis, and pro-inflammatory NO+ KCs. PPAR-γ activation reduces IRI and decreases the pro-inflammatory NO+ Kupffer cells. PPAR-γ activation can become an

  17. Polarization study

    International Nuclear Information System (INIS)

    Nurushev, S.B.

    1989-01-01

    Brief review is presented of the high energy polarization study including experimental data and the theoretical descriptions. The mostimportant proposals at the biggest accelerators and the crucial technical developments are also listed which may become a main-line of spin physics. 35 refs.; 10 figs.; 4 tabs

  18. Electron-positron pair production by gamma-rays in an anisotropic flux of soft photons, and application to pulsar polar caps

    Science.gov (United States)

    Voisin, Guillaume; Mottez, Fabrice; Bonazzola, Silvano

    2018-02-01

    Electron-positron pair production by collision of photons is investigated in view of application to pulsar physics. We compute the absorption rate of individual gamma-ray photons by an arbitrary anisotropic distribution of softer photons, and the energy and angular spectrum of the outgoing leptons. We work analytically within the approximation that 1 ≫ mc2/E > ɛ/E, with E and ɛ the gamma-ray and soft-photon maximum energy and mc2 the electron mass energy. We give results at leading order in these small parameters. For practical purposes, we provide expressions in the form of Laurent series which give correct reaction rates in the isotropic case within an average error of ˜ 7 per cent. We apply this formalism to gamma-rays flying downward or upward from a hot neutron star thermally radiating at a uniform temperature of 106 K. Other temperatures can be easily deduced using the relevant scaling laws. We find differences in absorption between these two extreme directions of almost two orders of magnitude, much larger than our error estimate. The magnetosphere appears completely opaque to downward gamma-rays while there are up to ˜ 10 per cent chances of absorbing an upward gamma-ray. We provide energy and angular spectra for both upward and downward gamma-rays. Energy spectra show a typical double peak, with larger separation at larger gamma-ray energies. Angular spectra are very narrow, with an opening angle ranging from 10-3 to 10-7 radians with increasing gamma-ray energies.

  19. Polarized atomic beams for targets

    International Nuclear Information System (INIS)

    Grueebler, W.

    1984-01-01

    The basic principle of the production of polarized atomic hydrogen and deuterium beams are reviewed. The status of the present available polarization, density and intensity are presented. The improvement of atomic beam density by cooling the hydrogen atoms to low velocity is discussed. The possible use of polarized atomic beams as targets in storage rings is shown. It is proposed that polarized atomic beams can be used to produce polarized gas targets with high polarization and greatly improved density

  20. Polarized positron sources for the future linear colliders

    International Nuclear Information System (INIS)

    Chaikovska, I.

    2012-01-01

    This thesis introduces the polarized positron source as one of the key element of the future Linear Collider (LC). In this context, the different schemes of the polarized positron source are described highlighting the main issues in this technology. In particular, the main focus is on the Compton based positron source adopted by the CLIC as a preferred option for the future positron source upgrade. In this case, the circularly polarized high energy gamma rays resulting from Compton scattering are directed to a production target where an electromagnetic cascade gives rise to the production of positrons by e + -e - pair conversion. To increase the efficiency of the gamma ray production stage, a multiple collision point line integrated in energy recovery linac is proposed. The simulations of the positron production, capture and primary acceleration allow to estimate the positron production efficiency and provide a simple parametrization of the Compton based polarized positron source in the view of the future LC requirements. The storage ring based Compton source option, so-called Compton ring, is also described. The main constraint of this scheme is given by the beam dynamics resulting in the large energy spread and increased bunch length affecting the gamma ray production rate. An original theoretical contribution is shown to calculate the energy spread induced by Compton scattering. Moreover, an experiment to test the gamma ray production by Compton scattering using a state-of-art laser system developed at LAL has been conducted in the framework of the 'Mighty Laser' project at the ATF, KEK. The experimental layout as well as the main results obtained are discussed in details. The studies carried out in this thesis show that the polarized positron source based on Compton scattering is a promising candidate for the future LC polarized positron source. (author)

  1. The high intensity {gamma}-ray source (HI{gamma}S) and recent results

    Energy Technology Data Exchange (ETDEWEB)

    Tonchev, A.P. [Duke University and TUNL, Triangle University Nuclear Laboratory, P.O. Box 90308, Durham, NC 27708 0308 (United States)]. E-mail: tonchev@tunl.duke.edu; Boswell, M. [University of North Carolina at Chapel Hill and TUNL, Chapel Hill, NC 27599 (United States); Howell, C.R. [Duke University and TUNL, Triangle University Nuclear Laboratory, P.O. Box 90308, Durham, NC 27708 0308 (United States); Karwowski, H.J. [University of North Carolina at Chapel Hill and TUNL, Chapel Hill, NC 27599 (United States); Kelley, J.H. [North Carolina State University and TUNL, Raleigh, NC 27695 (United States); Tornow, W. [Duke University and TUNL, Triangle University Nuclear Laboratory, P.O. Box 90308, Durham, NC 27708 0308 (United States); Wu, Y.K. [Duke University and Duke Free Electron Laser Laboratory, Durham, NC 27708-0319 (United States)

    2005-12-15

    The high intensity {gamma}-ray source (HI{gamma}S) utilizes intra-cavity backscattering of free electron laser photons from the Duke electron storage ring to produce a unique monoenergetic beam of high-flux {gamma}-rays with high polarization and selectable energy resolution. At present, {gamma}-ray beams with energies from 2 to 58 MeV are available with intensities as high as 10{sup 5}-5 x 10{sup 6} {gamma}/s, energy spreads of 3% or better, and nearly 100% linear polarization. The quality and intensity of the {gamma}-ray beams at HI{gamma}S are responsible for the unprecedented performance of this facility in a broad range of research programs in nuclear structure, nuclear astrophysics and nuclear applications. Recent results from excitation of isomeric states in ({gamma}, n) reactions and parity assignments of dipole states determined via the ({gamma}, {gamma}') reaction are presented.

  2. Peculiarities of annihilation of polarized positronium in polarized media

    International Nuclear Information System (INIS)

    Silenko, A.Ya.

    2005-01-01

    Features of positronium annihilation (PA) in polarized media are investigated. Strong exchange interaction with nonpaired electrons of paramagnetic atoms essentially accelerates the PA in comparison with annihilation of free positrons. The value of the spin projection on the direction of polarized nonpaired electrons has essential effect on the orthopositronium lifetime and on the width of the gamma spectrum annihilation line. It is shown that these features of PA permit to use it for studying the paramagnetic polarization [ru

  3. Polarized neutrons

    International Nuclear Information System (INIS)

    Williams, W.G.

    1988-01-01

    The book on 'polarized neutrons' is intended to inform researchers in condensed matter physics and chemistry of the diversity of scientific problems that can be investigated using polarized neutron beams. The contents include chapters on:- neutron polarizers and instrumentation, polarized neutron scattering, neutron polarization analysis experiments and precessing neutron polarization. (U.K.)

  4. Polarized Moessbauer transitions in mixed hyperfine interactions

    International Nuclear Information System (INIS)

    Barb, D.; Tarina, D.

    1975-01-01

    A contribution to the theory of elliptical polarization in the Moessbauer effect for transitions between mixed nuclear states is reported. A relation between the two-dimensional complex vector parameterization and the photon polarization density matrix was used in describing changes in the polarization of the gamma-ray involved. (A.K.)

  5. The Gamma Factory — new research opportunities for CERN

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    In this talk I shall discuss the recent initiative of broadening the present CERN research programme by including a new component exploiting a novel concept of the light source. The proposed, partially stripped ion beam driven, light source is the backbone of the Gamma Factory initiative. It could be realized at CERN by using the infrastructure of the already existing accelerators. It could push the intensity limits of the presently operating light-sources by at least 7 orders of magnitude, reaching the flux of the order of 10^17 photons/s, in the particularly interesting gamma-ray energy domain of 0.1 — 400 MeV. The partially stripped ion beams, the unprecedented-intensity energy-tuned gamma beams, together with the gamma-beam-driven secondary beams of polarized positrons, polarized muons, neutrinos, neutrons and radioactive ions constitute the basic research tools of the Gamma Factory. A broad spectrum of new research opportunities, in a vast domain of uncharted fundamental and applied physics territories...

  6. Polarized neutron capture in polarized 59Co and 165Ho nuclei

    International Nuclear Information System (INIS)

    Bosman, J.J.

    1976-01-01

    Gamma spectroscopy on the reactions 59 Co(n,γ) 60 Co and 165 Ho(n,γ) 166 Ho with polarized neutrons and polarized targets enabled the assignment of spins to 36 levels in 60 Co and 15 levels in 166 Ho. Several of them had not been reported earlier. The techniques used to polarize neutron beams and targets and the gamma-spectroscopy are extensively discussed

  7. Polarization: A Must for Fusion

    Directory of Open Access Journals (Sweden)

    Guidal M.

    2012-10-01

    Full Text Available Recent realistic simulations confirm that the polarization of the fuel would improve significantly the DT fusion efficiency. We have proposed an experiment to test the persistence of the polarization in a fusion process, using a terawatt laser hitting a polarized HD target. The polarized deuterons heated in the plasma induced by the laser can fuse producing a 3He and a neutron in the final state. The angular distribution of the neutrons and the change in the corresponding total cross section are related to the polarization persistence. The experimental polarization of DT fuel is a technological challenge. Possible paths for Magnetic Confinement Fusion (MCF and for Inertial Confinement Fusion (ICF are reviewed. For MCF, polarized gas can be used. For ICF, cryogenic targets are required. We consider both, the polarization of gas and the polarization of solid DT, emphasizing the Dynamic Nuclear polarization (DNP of HD and DT molecules.

  8. Gamma-ray burst polarimeter (GAP)

    International Nuclear Information System (INIS)

    Mihara, Tatehiro; Murakami, Toshio; Yonetoku, Daisuke; Gunji, Shuichi; Kubo, Shin

    2013-01-01

    The gamma-ray burst polarimeter (GAP: GAmma-ray burst Polarimeter), which had been almost handcrafted by scientists, has succeeded in working normally in interplanetary space, and in detecting the polarization of the gamma-ray from a mysterious astronomical object 'gamma-ray burst'. It is the first result of the detectors in the world exclusively aiming at detecting gamma-ray polarization. We mainly describe the hardware of our GAP equipment and show the method of preparing equipment to work in the cosmic space with a tight budget. The mechanical structure, the electronic circuits, the software on the equipment, the data analysis on the earth, and the scientific results gained by the observation just over one year, are presented after explaining the principle of gamma-ray polarization detection. Our design to protect equipment against mechanical shock and cosmic radiation may provide useful information for future preparation of compact satellite. (J.P.N.)

  9. T-odd angular correlations in the emission of prompt gamma rays and neutrons in nuclear fission induced by polarized neutrons

    International Nuclear Information System (INIS)

    Danilyan, G. V.; Klenke, J.; Krakhotin, V. A.; Kopach, Yu. N.; Novitsky, V. V.; Pavlov, V. S.; Shatalov, P. B.

    2011-01-01

    Study of the T-odd three-vector correlation in the emission of prompt neutrons from 235 U fission by polarized cold neutrons has been continued at the facility MEPHISTO of the FRM II reactor (Technical University of Munich). The sought correlation was not found within experimental error of 2.3 × 10 −5 . The upper limit for the asymmetry coefficient has been set to vertical bar D n vertical bar −5 at 99% confidence level, whereas for ternary fission correlation coefficient D α = (170±20) × 10 −5 . This limit casts doubt on a model that explains the three-vector correlation in ternary fission by the Coriolis mechanism. At the same time, five-vector correlation in the emission of prompt fission neutrons has been measured, which describes the rotation of the fissioning nucleus at the moment it breaks (ROT effect). At the angle 22.5° to the fission axis, the correlation coefficient was found to be (1.57 ± 0.20) × 10 −4 , while at the angle of 67.5° it is zero within the experimental uncertainty. The existence of ROT effect in the emission of prompt fission neutrons can be explained by the anisotropy of neutron emission in the rest frame of the fragment (fission fragments are aligned with respect to the axis of deformation of the fissioning nucleus), similar to the mechanism of ROT effect in the emission of prompt γ-rays.

  10. VCS-SSA Mainz Experiment. Measurement of the beam spin asymmetry in (e polarized p {yields} ep{gamma}) and (e polarized p {yields} ep{pi}{sup 0}). Final analysis - MEMO II

    Energy Technology Data Exchange (ETDEWEB)

    Fonvieille, H.; Bensafa, I. [LPC-Clermont-Fd, Universite Blaise Pascal, F-63170 Aubiere Cedex (France)

    2006-06-15

    MEMO-I was written in February 2006 to give details of the second pass analysis of the VCS-SSA experiment. Since then there was our VCS Meeting in March, the production of the PhD thesis by I. Bensafa in May, and complementary studies of the asymmetry which triggered some afterthoughts. Instead of updating MEMO-I which is long enough this memo summarizes these complementary remarks and proposes asymmetry results which are more finalized in view of publication. Various nomenclatures like cuts, variables,etc. have NOT been redefined: please read MEMO-I for that. (authors)

  11. The Effect of an Offset Polar Cap Dipolar Magnetic Field on the Modeling of the Vela Pulsar's Gamma-Ray Light Curves

    Science.gov (United States)

    Barnard, M.; Venter, C.; Harding, A. K.

    2016-01-01

    We performed geometric pulsar light curve modeling using static, retarded vacuum, and offset polar cap (PC) dipole B-fields (the latter is characterized by a parameter epsilon), in conjunction with standard two-pole caustic (TPC) and outer gap (OG) emission geometries. The offset-PC dipole B-field mimics deviations from the static dipole (which corresponds to epsilon equals 0). In addition to constant-emissivity geometric models, we also considered a slot gap (SG) E-field associated with the offset-PC dipole B-field and found that its inclusion leads to qualitatively different light curves. Solving the particle transport equation shows that the particle energy only becomes large enough to yield significant curvature radiation at large altitudes above the stellar surface, given this relatively low E-field. Therefore, particles do not always attain the radiation-reaction limit. Our overall optimal light curve fit is for the retarded vacuum dipole field and OG model, at an inclination angle alpha equals 78 plus or minus 1 degree and observer angle zeta equals 69 plus 2 degrees or minus 1 degree. For this B-field, the TPC model is statistically disfavored compared to the OG model. For the static dipole field, neither model is significantly preferred. We found that smaller values of epsilon are favored for the offset-PC dipole field when assuming constant emissivity, and larger epsilon values favored for variable emissivity, but not significantly so. When multiplying the SG E-field by a factor of 100, we found improved light curve fits, with alpha and zeta being closer to best fits from independent studies, as well as curvature radiation reaction at lower altitudes.

  12. Design and construction of the POLAR detector

    OpenAIRE

    Produit, N.; Bao, T. W.; Batsch, T.; Bernasconi, T.; Britvich, I.; Cadoux, F.; Cernuda, I.; Chai, J. Y.; Dong, Y. W.; Gauvin, N.; Hajdas, W.; Kole, M.; Kong, M. N.; Kramert, R.; Li, L.

    2017-01-01

    The POLAR detector is a space based Gamma Ray Burst (GRB) polarimeter with a wide field of view, which covers almost half the sky. The instrument uses Compton scattering of gamma rays on a plastic scintillator hodoscope to measure the polarization of the incoming photons. The instrument has been successfully launched on board of the Chinese space laboratory Tiangong~2 on September 15, 2016. The construction of the instrument components is described in this article. Details are provided on pro...

  13. Gamma-ray angular distribution and correlation measurement. II

    International Nuclear Information System (INIS)

    Twin, P.J.

    1975-01-01

    Angular correlations of γ-rays following nuclear reactions depend, in general, on some alignment of the γ-emitting initial state. The methods of alignment are briefly discussed and then the techniques and experimental methods associated with direct angular distributions, particle-gamma correlations, gamma-gamma correlations and linear polarization correlations are dealt with. Finally the inherent ambiguities which arise when different spin and delta values give identical correlations are discussed for the simple direct and particle-gamma correlations together with the question whether the larger information content of gamma-gamma and linear polarization correlations can resolve these ambiguities. (Auth.)

  14. Assessment of gamma radiation exposure inside a newly constructed building and a proposed regulatory guideline for exposure control from natural radioactivity in future buildings

    International Nuclear Information System (INIS)

    Shukla, V.K.; Sadasivan, S.; Sundaram, V.K.; Nambi, K.S.V.

    1995-01-01

    Naturally occurring radionuclides in building materials are one of the sources of radiation exposure of the population. The various materials used for constructing a new building were assessed for 40 K, 232 Th and 238 U radioactivity and the external gamma dose rate inside the building was predicted by using the computer code QAD-CGGP. The external dose rate was also measured by a scintillation gamma monitor after the construction of the building. In the building studied, the floor and the ceilings are seen to contribute about 35% each of the total radiation dose inside the building from the natural radioactivity present in the construction materials and the underlying soil; the walls contributed about 15%. A sensitivity analysis assuming extreme conditions of radioactivity concentrations as are normally observed in the Indian context, indicates the possibility of indoor gamma radiation fields varying by two orders of magnitude. The possible control methodologies and recommendations are also discussed for keeping the population exposure as low as reasonable achievable. It is evaluated that radioactivity limits of 370 Bq.kg -1 of radium equivalent and 85 Bq.kg -1 of 226 Ra when applied concurrently, might limit the indoor exposure to reasonably accepted low levels of health risks. (author)

  15. Polarization phenomena of nuclear force and weak interaction

    International Nuclear Information System (INIS)

    Konuma, Michitsugu

    1982-01-01

    As one of the projects at the National Laboratory of High Energy Physics (KEK), the measurement of parity non-conservation component in nuclear force was proposed. The theoretical survey of this proposal is reported. The non-relativistic parity non-conserving potential between nucleons can be obtained from the interaction between a quark and a gauge boson. The wave function of a nucleus, which includes the inverse components of the parity, can be written. A practical experiment was designed. The mixing of the inverse components and the interference of an inverse component in the 1042 keV and 1081 keV levels of F 18 may produce the parity non-conservation. The processes which suggest the existence of parity non-conservation were studied. The processes are the circular polarization of gamma-ray emitted from a nucleus, the angular distribution of gamma-ray emitted from polarized nuclei, the collision of the proton beam with helicity of plus and minus on other nuclei, the spin rotation of neutrons, and the alpha decay of the parity non-conservation. The preliminary results of the experiment on the effects of parity non-conservation in the collision process of polarized proton beam have been reported, and the theoretical analyses were performed. The violation of parity conservation in large momentum collision is discussed. The comparison of the theoretical results with the experimental ones is presented. (Kato, T.)

  16. Asymmetry of the cross section for the reaction. gamma. d. -->. pn induced by linearly polarized. gamma. rays in the energy region E/sub. gamma. / = 0. 4--0. 8 GeV and theta/sup c. m. //sub p/ = 45/sup 0/--95/sup 0/

    Energy Technology Data Exchange (ETDEWEB)

    Adamyan, F.V.; Akopyan, G.G.; Vartapetyan, G.A.; Galumyan, P.I.; Grabskii, V.O.; Karapetyan, V.V.; Karapetyan, G.V.

    1984-03-10

    The asymmetry (..sigma..) of the cross section for the reaction ..gamma..d..-->..pn has been measured for the energy range E/sub ..gamma../ = 0.4--0.8 GeV and for the angular interval theta/sup c.m.//sub p/ = 45/sup 0/--95/sup 0/. The results are at odds with the calculations by Ogawa et al. and by Huneke, both based on phenomenological models, and also with the predictions of the partial-wave analysis by Ideda et al., which incorporates dibaryon resonances.

  17. A Proposal submitted to Biological Systems Science Division of DOE requesting Participant Support Costs for the Fifth International Conference on Polar and Alpine Microbiology

    Energy Technology Data Exchange (ETDEWEB)

    Priscu, John [Montana State Univ., Bozeman, MT (United States)

    2012-11-20

    The 5th International Conference on Polar and Alpine Microbiology (PAM5) was held in Big Sky, Montana (USA) from 8-12 September 2013. This meeting is a continuation of the highly successful meetings previously held in Rovaniemi, Finland (2004), Innsbruck, Austria (2006), Banff, Canada (2008) and Ljubljana, Slovenia (2011), which brought together leading international researchers and students in this field. The objectives of the Big Sky meeting were to bring together scientists, students and professionals to discuss all aspects of cold-adapted microorganisms and the roles they play in polar and alpine environments, to understand the role of these organisms in our search for life on other icy worlds, to address recent developments, and to exchange ideas and experiences on an international scale. The conference provided a multi-disciplinary forum to explore emerging areas in the field and as always, will have a wealth of opportunities for the exchange of ideas and building of collaborations. Funds were requested to help defray registration fees and travel costs of 13 early career scientists. Distribution of the funds were based on the quality of the abstracts submitted.

  18. Gamma Knife

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Gamma Knife Gamma Knife® is a radiation therapy that uses computerized ... If you're scheduled for radiation therapy using Gamma Knife®, a treatment team consisting of a radiation ...

  19. Measurement of γ-quanta beam polarization

    International Nuclear Information System (INIS)

    Luchkov, B.I.; Tugaenko, V.Yu.; Maishev, V.A.

    1992-01-01

    A beam of polarized γ-quanta is produced and its polarization degree is measured. The experiment is conducted using an electron beam of the Serpukhov accelerator at the 'Kaskad' facility. 28 GeV energy electrons are recorded in a proportional chamber after which they enter a 15 mm thickness silicon crystal. After passing the second proportional chamber the electrons get into complete absorption spectrometer where their energy is measured, and the emitted gamma quanta get to 30 mm thickness silicon crystal. E + e - -pair coordinates are measured in the third proportional chamber. Gamma-quantum polarization value of 0.3±0.1 is obtained. 1 ref.; 1 fig

  20. Proposal of balloon and satellite observations of MeV gammas using Electron Tracking Compton Camera for reaching a high sensitivity of 1 mCrab

    Science.gov (United States)

    Takada, Atsushi; Tanimori, Toru

    2016-04-01

    ETCC with a gas Time Projection Chamber (TPC) and pixel GSO scintillators, by measuring electron tracks precisely, provides both a strong background rejection by dE/dx of the track and well-defined 2-dimensional Point Spread Function (PDF) with better than several degrees by adding the arc direction of incident gammas (SPD: Scatter Plane Deviation) with the ARM (angular Resolution Measure) direction measured in standard Compton Camera (CC). In 2006 its background rejection was revealed by SMILE-I balloon experiment with 10cm-cubic ETCC using the dE/dx of tracks. In 2013, 30cm-cube-ETCC has been developed to catch gammas from Crab in next SMILE-II balloon with >5sigma detection for 4 hrs. Now its sensitivity has been improved to 10sigma by attaining the angular resolution of the track (SPD angle) to that determined by multiple scattering of the gas. Thus, we show the ability of ETCC to give a better significance by a factor of 10 than that of standard CCs having same detection area by electron tracking?and we have found that SPD is an essential to define the PSF of Compton imaging quantitatively. Such a well-defined PSF is, for the first time, able to provide reliable sensitivity in Compton imaging without assuming the use of optimization algorithm. These studies uncover the uncertainties of CCs from both points of view of the intense background and the difficulty of the definition of the PSF, and overcome the above problems. Based on this technology, SMILE-II with 3atm CF4 gas is expected to provide a 5times better sensitivity than COMPTEL in one month balloon, and 4modules of 50cm-cube ETCCs would exceed over 10^-12 erg/cm^2s^1 (1mCrab) in satellite. Here we summarize the performance of the ETCC and new astrophysics opened in near future by high sensitive observation of MeV gamma-rays.

  1. Polarization developments

    International Nuclear Information System (INIS)

    Prescott, C.Y.

    1993-07-01

    Recent developments in laser-driven photoemission sources of polarized electrons have made prospects for highly polarized electron beams in a future linear collider very promising. This talk discusses the experiences with the SLC polarized electron source, the recent progress with research into gallium arsenide and strained gallium arsenide as a photocathode material, and the suitability of these cathode materials for a future linear collider based on the parameters of the several linear collider designs that exist

  2. Polarized proton colliders

    International Nuclear Information System (INIS)

    Roser, T.

    1995-01-01

    High energy polarized beam collisions will open up the unique physics opportunities of studying spin effects in hard processes. This will allow the study of the spin structure of the proton and also the verification of the many well documented expectations of spin effects in perturbative QCD and parity violation in W and Z production. Proposals for polarized proton acceleration for several high energy colliders have been developed. A partial Siberian Snake in the AGS has recently been successfully tested and full Siberian Snakes, spin rotators, and polarimeters for RHIC are being developed to make the acceleration of polarized beams to 250 GeV possible. This allows for the unique possibility of colliding two 250 GeV polarized proton beams at luminosities of up to 2 x 10 32 cm -2 s -1

  3. Neutron polarization

    International Nuclear Information System (INIS)

    Firk, F.W.K.

    1976-01-01

    Some recent experiments involving polarized neutrons are discussed; they demonstrate how polarization studies provide information on fundamental aspects of nuclear structure that cannot be obtained from more traditional neutron studies. Until recently, neutron polarization studies tended to be limited either to very low energies or to restricted regions at higher energies, determined by the kinematics of favorable (p, vector n) and (d, vector n) reactions. With the advent of high intensity pulsed electron and proton accelerators and of beams of vector polarized deuterons, this is no longer the case. One has entered an era in which neutron polarization experiments are now being carried out, in a routine way, throughout the entire range from thermal energies to tens-of-MeV. The significance of neutron polarization studies is illustrated in discussions of a wide variety of experiments that include the measurement of T-invariance in the β-decay of polarized neutrons, a search for the effects of meson exchange currents in the photo-disintegration of the deuteron, the determination of quantum numbers of states in the fission of aligned 235 U and 237 Np induced by polarized neutrons, and the double- and triple-scattering of fast neutrons by light nuclei

  4. Polarization holography

    DEFF Research Database (Denmark)

    Nikolova, L.; Ramanujam, P.S.

    Current research into holography is concerned with applications in optically storing, retrieving, and processing information. Polarization holography has many unique properties compared to conventional holography. It gives results in high efficiency, achromaticity, and special polarization...... properties. This books reviews the research carried out in this field over the last 15 years. The authors provide basic concepts in polarization and the propagation of light through anisotropic materials, before presenting a sound theoretical basis for polarization holography. The fabrication...... and characterization of azobenzene based materials, which remain the most efficient for the purpose, is described in detail. This is followed by a description of other materials that are used in polarization holography. An in-depth description of various applications, including display holography and optical storage...

  5. Inverse compton emission of gamma rays near the pulsar surface

    International Nuclear Information System (INIS)

    Morini, M.

    1981-01-01

    The physical conditions near pulsar surface that might give rise to gamma ray emission from Crab and Vela pulsars are not yet well understood. Here I suggest that, in the context of the vacuum discharge mechanism proposed by Ruderman and Sutherland (1975), gamma rays are produced by inverse Compton scattering of secondary electrons with the thermal radiation of the star surface as well as for curvature and synchotron radiation. It is found that inverse Compton scattering is relevant if the neutron star surface temperature is greater than 10 6 K or of the polar cap temperature is of the order of 5 x 10 6 K. Inverse Compton scattering in anisotropic photon fields and Klein-Nishina regime is here carefully considered. (orig.)

  6. A Si nanocube array polarizer

    Science.gov (United States)

    Chen, Linghua; Jiang, Yingjie; Xing, Li; Yao, Jun

    2017-10-01

    We have proposed a full dielectric (silicon) nanocube array polarizer based on a silicon dioxide substrate. Each polarization unit column includes a plurality of equal spaced polarization units. By optimizing the length, the width, the height of the polarization units and the center distance of adjacent polarization unit (x direction and y direction), an extinction ratio (ER) of higher than 25dB was obtained theoretically when the incident light wavelength is 1550nm. while for applications of most polarization optical elements, ER above 10dB is enough. With this condition, the polarizer we designed can work in a wide wavelength range from 1509.31nm to 1611.51nm. Compared with the previous polarizer, we have introduced a polarizer which is a full dielectric device, which solves the problems of low efficiency caused by Ohmic loss and weak coupling. Furthermore, compared with the existing optical polarizers, our polarizer has the advantages of thin thickness, small size, light weight, and low processing difficulty, which is in line with the future development trend of optical elements.

  7. Fluorescence confocal polarizing microscopy

    Indian Academy of Sciences (India)

    Much of the modern understanding of orientational order in liquid crystals (LCs) is based on polarizing microscopy (PM). A PM image bears only two-dimensional (2D) information, integrating the 3D pattern of optical birefringence over the path of light. Recently, we proposed a technique to image 3D director patterns by ...

  8. Ionic polarization

    International Nuclear Information System (INIS)

    Mahan, G.D.

    1992-01-01

    Ferroelectricity occurs in many different kinds of materials. Many of the technologically important solids, which are ferroelectric, can be classified as ionic. Any microscopic theory of ferroelectricity must contain a description of local polarization forces. We have collaborated in the development of a theory of ionic polarization which is quite successful. Its basic assumption is that the polarization is derived from the properties of the individual ions. We have applied this theory successfully to diverse subjects as linear and nonlinear optical response, phonon dispersion, and piezoelectricity. We have developed numerical methods using the local Density approximation to calculate the multipole polarizabilities of ions when subject to various fields. We have also developed methods of calculating the nonlinear hyperpolarizability, and showed that it can be used to explain light scattering experiments. This paper elaborates on this polarization theory

  9. Gamma gamma technology group

    Indian Academy of Sciences (India)

    The purpose of the meeting was to form a group of people who ... able by looking at the energy deposited at the face of the final dipole, 4.5 m from ... A F Zarnecki has made a good start on background studies, V Telnov has proposed.

  10. Polarization experiments

    International Nuclear Information System (INIS)

    Halzen, F.

    1977-02-01

    In a theoretical review of polarization experiments two important points are emphasized: (a) their versatility and their relevance to a large variety of aspects of hadron physics (tests of basic symmetries; a probe of strong interaction dynamics; a tool for hadron spectroscopy); (b) the wealth of experimental data on polarization parameters in pp and np scattering in the Regge language and in the diffraction language. (author)

  11. Study by polarized muon

    International Nuclear Information System (INIS)

    Yamazaki, Toshimitsu

    1977-01-01

    Experiments by using polarized muon beam are reported. The experiments were performed at Berkeley, U.S.A., and at Vancouver, Canada. The muon spin rotation is a useful method for the study of the spin polarization of conductive electrons in paramagnetic Pd metal. The muon Larmor frequency and the relaxation time can be obtained by measuring the time distribution of decay electrons of muon-electron process. The anomalous depolarization of negative muon spin rotation in the transitional metal was seen. The circular polarization of the negative muon X-ray was measured to make clear this phenomena. The experimental results show that the anomalous depolarization is caused at the 1-S-1/2 state. For the purpose to obtain the strong polarization of negative muon, a method of artificial polarization is proposed, and the test experiments are in progress. The study of the hyperfine structure of mu-mesic atoms is proposed. The muon capture rate was studied systematically. (Kato, T.)

  12. Polarization measurement for internal polarized gaseous targets

    International Nuclear Information System (INIS)

    Ye Zhenyu; Ye Yunxiu; Lv Haijiang; Mao Yajun

    2004-01-01

    The authors present an introduction to internal polarized gaseous targets, polarization method, polarization measurement method and procedure. To get the total nuclear polarization of hydrogen atoms (including the polarization of the recombined hydrogen molecules) in the target cell, authors have measured the parameters relating to atomic polarization and polarized hydrogen atoms and molecules. The total polarization of the target during our measurement is P T =0.853 ± 0.036. (authors)

  13. The definition of cross polarization

    DEFF Research Database (Denmark)

    Ludwig, Arthur

    1973-01-01

    There are at least three different definitions of cross polarization used in the literature. The alternative definitions are discussed with respect to several applications, and the definition which corresponds to one standard measurement practice is proposed as the best choice....

  14. X-Ray and Optical Study of the Gamma-ray Source 3FGL J0838.8–2829: Identification of a Candidate Millisecond Pulsar Binary and an Asynchronous Polar

    Energy Technology Data Exchange (ETDEWEB)

    Halpern, Jules P.; Bogdanov, Slavko [Columbia Astrophysics Laboratory, Columbia University, 550 West 120th Street, New York, NY 10027-6601 (United States); Thorstensen, John R., E-mail: jules@astro.columbia.edu [Department of Physics and Astronomy, 6127 Wilder Laboratory, Dartmouth College, Hanover, NH 03755-3528 (United States)

    2017-04-01

    We observed the field of the Fermi source 3FGL J0838.8−2829 in optical and X-rays, initially motivated by the cataclysmic variable (CV) 1RXS J083842.1−282723 that lies within its error circle. Several X-ray sources first classified as CVs have turned out to be γ -ray emitting millisecond pulsars (MSPs). We find that 1RXS J083842.1−282723 is in fact an unusual CV, a stream-fed asynchronous polar in which accretion switches between magnetic poles (that are ≈120° apart) when the accretion rate is at minimum. High-amplitude X-ray modulation at periods of 94.8 ± 0.4 minutes and 14.7 ± 1.2 hr are seen. The former appears to be the spin period, while the latter is inferred to be one-third of the beat period between the spin and the orbit, implying an orbital period of 98.3 ± 0.5 minutes. We also measure an optical emission-line spectroscopic period of 98.413 ± 0.004 minutes, which is consistent with the orbital period inferred from the X-rays. In any case, this system is unlikely to be the γ -ray source. Instead, we find a fainter variable X-ray and optical source, XMMU J083850.38−282756.8, that is modulated on a timescale of hours in addition to exhibiting occasional sharp flares. It resembles the black widow or redback pulsars that have been discovered as counterparts of Fermi sources, with the optical modulation due to heating of the photosphere of a low-mass companion star by, in this case, an as-yet undetected MSP. We propose XMMU J083850.38−282756.8 as the MSP counterpart of 3FGL J0838.8−2829.

  15. Sources of polarized neutrons

    International Nuclear Information System (INIS)

    Walter, L.

    1983-01-01

    Various sources of polarized neutrons are reviewed. Monoenergetic source produced with unpolarized or polarized beams, white sources of polarized neutrons, production by transmissions through polarized hydrogen targets and polarized thermal neutronsare discussed, with appropriate applications included. (U.K.)

  16. Design and construction of the POLAR detector

    Science.gov (United States)

    Produit, N.; Bao, T. W.; Batsch, T.; Bernasconi, T.; Britvich, I.; Cadoux, F.; Cernuda, I.; Chai, J. Y.; Dong, Y. W.; Gauvin, N.; Hajdas, W.; Kole, M.; Kong, M. N.; Kramert, R.; Li, L.; Liu, J. T.; Liu, X.; Marcinkowski, R.; Orsi, S.; Pohl, M.; Rapin, D.; Rybka, D.; Rutczynska, A.; Shi, H. L.; Socha, P.; Sun, J. C.; Song, L. M.; Szabelski, J.; Traseira, I.; Xiao, H. L.; Wang, R. J.; Wen, X.; Wu, B. B.; Zhang, L.; Zhang, L. Y.; Zhang, S. N.; Zhang, Y. J.; Zwolinska, A.

    2018-01-01

    The POLAR detector is a space based Gamma Ray Burst (GRB) polarimeter with a wide field of view, which covers almost half the sky. The instrument uses Compton scattering of gamma rays on a plastic scintillator hodoscope to measure the polarization of the incoming photons. The instrument has been successfully launched on board of the Chinese space laboratory Tiangong 2 on September 15, 2016. The construction of the instrument components is described in this article. Details are provided on problems encountered during the construction phase and their solutions. Initial performance of the instrument in orbit is as expected from ground tests and Monte Carlo simulation.

  17. Gamma astronomy

    International Nuclear Information System (INIS)

    Cesarsky, C.; Cesarsky, J.P.

    1986-01-01

    This article overviews the gamma astronomy research. Sources already observed, and what causes to give to them; the galactic radiation and its interpretation; techniques already used and current projects [fr

  18. Gamma Spectroscopy

    NARCIS (Netherlands)

    Niemantsverdriet, J.W.; Butz, Tilman; Ertl, G.; Knözinger, H.; Schüth, F.

    2008-01-01

    No abstract. The sections in this article are 1 Introduction 2 Mössbauer Spectroscopy 3 Time-Differential Perturbed Angular Correlations (TDPAC) 4 Conclusions and Outlook Keywords: Mössbauer spectroscopy; gamma spectroscopy; perturbed angular correlation; TDPAC

  19. Microwave-gated dynamic nuclear polarization

    DEFF Research Database (Denmark)

    Bornet, Aurélien; Pinon, Arthur; Jhajharia, Aditya

    2016-01-01

    Dissolution dynamic nuclear polarization (D-DNP) has become a method of choice to enhance signals in nuclear magnetic resonance (NMR). Recently, we have proposed to combine cross-polarization (CP) with D-DNP to provide high polarization P((13)C) in short build-up times. In this paper, we show...

  20. 2$^{+}$ anomaly and configurational isospin polarization of $^{136}$Te

    CERN Multimedia

    It is proposed to perform a Coulomb excitation experiment on beams of radioactive ions of $^{136}$Te delivered by HIE-ISOLDE impinging on a $^{58}$Ni target. Scattered particles will be detected by a DSSSD detector and $\\gamma$-rays will be detected by the MINIBALL array. The proposed Configurational Isospin Polarization (CIP) of the two lowest 2$^+$ states will be determined by measuring the E2 excitation yield distribution to them. The expected proton-dominated one-phonon character of the second excited 2$^+$ state of $^{136}$Te will be tested on the basis of absolute electromagnetic matrix elements from the observed Coulomb excitation cross sections. Complementary lifetime information on this predominant 2$^+_{1,ms}$ state will be extracted using the differential DSAM technique. The experiment will clarify to what extent CIP is responsible for the 2$^+$ anomaly in $^{136}$Te.

  1. Polar Stratigraphy

    Science.gov (United States)

    1999-01-01

    These three images were taken on three different orbits over the north polar cap in April 1999. Each shows a different part of the same ice-free trough. The left and right images are separated by a distance of more than 100 kilometers (62 miles). Note the similar layers in each image.

  2. Automation of scanning technique by gamma radiation

    International Nuclear Information System (INIS)

    Aamira, Yahya

    2011-01-01

    The gamma scan technique is a nuclear test allowing the analysis of the internal mechanical properties of distillation columns used in petrochemical industries. Such technique is performed manually. So we propose in this work to automate the gamma scan procedure test by using a PLC. In addition, supervision and data acquisition interfaces are proposed.

  3. Simultaneous neutron and gamma spectrum adjustment

    International Nuclear Information System (INIS)

    Remec, I.

    1996-01-01

    The spectrum adjustment procedure was extended to simultaneous neutron and gamma spectrum adjustment, and the feasibility of this technique is demonstrated in the analysis of HFIR dosimetry experiments. Conditions in which gamma rays may contribute considerably to radiation damage in steels are discussed. Beryllium helium accumulation fluence monitors (HAFMs) were found to be good monitors in gamma fields of intensities high enough to contribute to steel embrittlement. Use of 237 Np, 238 U, and 9 Be HAFM as gamma dosimeters is proposed for high-dose irradiations in high-energy, high-intensity gamma fields

  4. Gamma camera

    International Nuclear Information System (INIS)

    Berninger, W.H.

    1975-01-01

    The light pulse output of a scintillator, on which incident collimated gamma rays impinge, is detected by an array of photoelectric tubes each having a convexly curved photocathode disposed in close proximity to the scintillator. Electronic circuitry connected to outputs of the phototubes develops the scintillation event position coordinate electrical signals with good linearity and with substantial independence of the spacing between the scintillator and photocathodes so that the phototubes can be positioned as close to the scintillator as is possible to obtain less distortion in the field of view and improved spatial resolution as compared to conventional planar photocathode gamma cameras

  5. Dynamic polarization of radioactive nuclei

    International Nuclear Information System (INIS)

    Kiselev, Yu.F.; Lyuboshits, V.L.; )

    2001-01-01

    Radioactive nuclei, embedded into a frozen polarized proton target, atr proposed to polarize by means of some dynamic polarization methods. Angular distributions of γ-quanta emitted ny 22 Na(3 + ) in the cascade β-γ-radiation are calculated. It is shown that this distribution does not depend on the spin temperature sing at the Boltzmann distribution of populations among the Zeeman magnetic substates, whereas the tensor polarization of quadrupole nuclei, placed in the electric field of the crystal, causes the considerable sing dependence. The new method promises wide opportunities for the magnetic structure investigations as well as for the study of spin-spin interaction dynamics of rare nuclei in dielectrics. Physical-technical advantages and disadvantages of the given method are discussed for the polarization of heavy nuclei in the on-line implantation mode [ru

  6. 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....

  7. Gamma camera

    International Nuclear Information System (INIS)

    Tschunt, E.; Platz, W.; Baer, Ul; Heinz, L.

    1978-01-01

    A gamma camera has a plurality of exchangeable collimators, one of which is replaceably mounted in the ray inlet opening of the camera, while the others are placed on separate supports. Supports are swingably mounted upon a column one above the other

  8. Gamma camera

    International Nuclear Information System (INIS)

    Schlosser, P.A.; Steidley, J.W.

    1980-01-01

    The design of a collimation system for a gamma camera for use in nuclear medicine is described. When used with a 2-dimensional position sensitive radiation detector, the novel system can produce superior images than conventional cameras. The optimal thickness and positions of the collimators are derived mathematically. (U.K.)

  9. Polarization bremsstrahlung in α decay

    International Nuclear Information System (INIS)

    Amusia, M. Ya.; Zon, B. A.; Kretinin, I. Yu.

    2007-01-01

    A mechanism of formation of electromagnetic radiation that accompanies α decay and is associated with the emission of photons by electrons of atomic shells due to the scattering of α particles by these atoms (polarization bremsstrahlung) is proposed. It is shown that, when the photon energy is no higher than the energy of K electrons of an atom, polarization bremsstrahlung makes a significant contribution to the bremsstrahlung in α decay

  10. Polar Polygons

    Science.gov (United States)

    2005-01-01

    18 August 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark-outlined polygons on a frost-covered surface in the south polar region of Mars. In summer, this surface would not be bright and the polygons would not have dark outlines--these are a product of the presence of seasonal frost. Location near: 77.2oS, 204.8oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Spring

  11. Complete $O(\\alpha)$ QED corrections to polarized Compton scattering

    CERN Document Server

    Denner, Ansgar

    1999-01-01

    The complete QED corrections of O(alpha) to polarized Compton scattering are calculated for finite electron mass and including the real corrections induced by the processes e^- gamma -> e^- gamma gamma and e^- gamma -> e^- e^- e^+. All relevant formulas are listed in a form that is well suited for a direct implementation in computer codes. We present a detailed numerical discussion of the O(alpha)-corrected cross section and the left-right asymmetry in the energy range of present and future Compton polarimeters, which are used to determine the beam polarization of high-energetic e^+- beams. For photons with energies of a few eV and electrons with SLC energies or smaller, the corrections are of the order of a few per mille. In the energy range of future e^+e^- colliders, however, they reach 1-2% and cannot be neglected in a precision polarization measurement.

  12. Strategic Polarization.

    Science.gov (United States)

    Kalai, Adam; Kalai, Ehud

    2001-08-01

    In joint decision making, similarly minded people may take opposite positions. Consider the example of a marriage in which one spouse gives generously to charity while the other donates nothing. Such "polarization" may misrepresent what is, in actuality, a small discrepancy in preferences. It may be that the donating spouse would like to see 10% of their combined income go to charity each year, while the apparently frugal spouse would like to see 8% donated. A simple game-theoretic analysis suggests that the spouses will end up donating 10% and 0%, respectively. By generalizing this argument to a larger class of games, we provide strategic justification for polarization in many situations such as debates, shared living accommodations, and disciplining children. In some of these examples, an arbitrarily small disagreement in preferences leads to an arbitrarily large loss in utility for all participants. Such small disagreements may also destabilize what, from game-theoretic point of view, is a very stable equilibrium. Copyright 2001 Academic Press.

  13. Gamma camera

    International Nuclear Information System (INIS)

    Reiss, K.H.; Kotschak, O.; Conrad, B.

    1976-01-01

    A gamma camera with a simplified setup as compared with the state of engineering is described permitting, apart from good localization, also energy discrimination. Behind the usual vacuum image amplifier a multiwire proportional chamber filled with trifluorine bromium methane is connected in series. Localizing of the signals is achieved by a delay line, energy determination by means of a pulse height discriminator. With the aid of drawings and circuit diagrams, the setup and mode of operation are explained. (ORU) [de

  14. Gamma irradiator

    International Nuclear Information System (INIS)

    Simonet, G.

    1986-09-01

    Fiability of devices set around reactors depends on material resistance under irradiation noticeably joints, insulators, which belongs to composition of technical, safety or physical incasurement devices. The irradiated fuel elements, during their desactivation in a pool, are an interesting gamma irradiation device to simulate damages created in a nuclear environment. The existing facility at Osiris allows to generate an homogeneous rate dose in an important volume. The control of the element distances to irradiation box allows to control this dose rate [fr

  15. Gamma teletopography

    International Nuclear Information System (INIS)

    Simonet, G.

    1987-06-01

    The mapping of gamma sources radiation emission in a nuclear plant is an important safety point. A remote gamma ray mapping process was developed in SPS/CEA/SACLAY. It uses the ''pinhole camera'' principle, precursor of photography. It mainly consists of a radiation proof box, with a small orifice, containing sensitive emulsions at the opposite. A first conventional photographic type emulsion photographs the area. A second photographic emulsion shows up the gamma radiations. The superim position of the two shots gives immediate informations of the precise location of each source of radiation in the observed area. To make easier the presentation and to improve the accuracy of the results for radiation levels mapping, the obtained films are digitally processed. The processing assigns a colours scale to the various levels of observed radiations. Taking account physical data and standard parameters, it gets possible to estimate the dose rate. The device is portable. Its compactness and fully independent nature make it suitable for use anywhere. It can be adapted to a remote automatic handling system, robot... so as to avoid all operator exposure when the local dose rate is too high [fr

  16. Polarized secondary radioactive beams

    International Nuclear Information System (INIS)

    Zaika, N.I.

    1992-01-01

    Three methods of polarized radioactive nuclei beam production: a) a method nuclear interaction of the non-polarized or polarized charged projectiles with target nuclei; b) a method of polarization of stopped reaction radioactive products in a special polarized ion source with than following acceleration; c) a polarization of radioactive nuclei circulating in a storage ring are considered. Possible life times of the radioactive ions for these methods are determined. General schemes of the polarization method realizations and depolarization problems are discussed

  17. Polar crane

    International Nuclear Information System (INIS)

    Makosinski, S.

    1981-01-01

    In many applications polar cranes have to be repeatedly positioned with high accuracy. A guidance system is disclosed which has two pairs of guides. Each guide consists of two rollers carried by a sheave rotatable mounted on the crane bridge, the rollers being locatable one on each side of a guideway, e.g. the circular track on which the bridge runs. The pairs of guides are interconnected by respective rope loops which pass around and are locked to the respective pairs of sheaves in such a manner that movement of one guide results in equal movement of the other guide in a sense to maintain the repeatability of positioning of the centre of the bridge. A hydraulically-linked guide system is also described. (author)

  18. Polarization-multiplexing ghost imaging

    Science.gov (United States)

    Dongfeng, Shi; Jiamin, Zhang; Jian, Huang; Yingjian, Wang; Kee, Yuan; Kaifa, Cao; Chenbo, Xie; Dong, Liu; Wenyue, Zhu

    2018-03-01

    A novel technique for polarization-multiplexing ghost imaging is proposed to simultaneously obtain multiple polarimetric information by a single detector. Here, polarization-division multiplexing speckles are employed for object illumination. The light reflected from the objects is detected by a single-pixel detector. An iterative reconstruction method is used to restore the fused image containing the different polarimetric information by using the weighted sum of the multiplexed speckles based on the correlation coefficients obtained from the detected intensities. Next, clear images of the different polarimetric information are recovered by demultiplexing the fused image. The results clearly demonstrate that the proposed method is effective.

  19. Future prospects for. gamma. -ray astronomy

    Energy Technology Data Exchange (ETDEWEB)

    Fichtel, C [National Aeronautics and Space Administration, Greenbelt, MD (USA). Goddard Space Flight Center

    1981-06-30

    As ..gamma..-ray astronomy moves from the discovery to the exploratory phase, the promise of ..gamma..-ray astrophysics noted by theorists in the late 1940s and 1950s is beginning to be realized. In the future, satellites should carry instruments that will have over an order of magnitude greater sensitivity than those flown thus far, and, for at least some portions of the ..gamma..-ray energy range, these detectors will also have substantially improved energy and angular resolution. The information to be obtained from these experiments should greatly enhance our knowledge of several astrophysical phenomena including the very energetic and nuclear processes associated with compact objects, astrophysical nucleosynthesis, solar particle acceleration, the chemical composition of the planets and other bodies of the Solar System, the structure of our Galaxy, the origin and dynamic pressure effects of the cosmic rays, high energy particles and energetic processes in other galaxies especially active ones, and the degree of matter-antimatter symmetry of the Universe. The ..gamma..-ray results of the forthcoming programs such as Gamma-I, the Gamma Ray Observatory, the ..gamma..-ray burst network, Solar Polar, and very high energy ..gamma..-ray telescopes on the ground will almost certainly provide justification for more sophisticated telescopes. These advanced instruments might be placed on the Space Platform currently under study by N.A.S.A.

  20. Investigation of {sup 136} Ba gamma-Transitions in the (n,n` gamma) Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Sergiwa, S M [University of Garyuonis, Benghazi, (Libyan Arab Jamahiriya); Rateb, G M; Zleetni, S M; dufani, M M; Shermit, A M; Al Hamidi, M M [Tajoura Nuclear Research Center, Tripoli, (Libyan Arab Jamahiriya); El-Ahrash, M S [7th of April University, Zawia, (Libyan Arab Jamahiriya)

    1995-10-01

    Using the reactor fast neutron beam, angular distribution and linear polarization of gamma-rays emitted from the {sup 136} Ba (n,n` gamma) reaction were measured. From these measurements, a decay scheme of {sup 1}36{sup B}a has been constructed. New spin and parity (J{pi}) assignments as well as resolving ambiguities in previous assignments for some levels were done. In addition, multipole mixing rations ({delta} - values, important for model comparison) have been unambiguously determined for many gamma-transitions. 1 fig., 2 tabs.

  1. Testing gravitational parity violation with coincident gravitational waves and short gamma-ray bursts

    International Nuclear Information System (INIS)

    Yunes, Nicolas; O'Shaughnessy, Richard; Owen, Benjamin J.; Alexander, Stephon

    2010-01-01

    Gravitational parity violation is a possibility motivated by particle physics, string theory, and loop quantum gravity. One effect of it is amplitude birefringence of gravitational waves, whereby left and right circularly polarized waves propagate at the same speed but with different amplitude evolution. Here we propose a test of this effect through coincident observations of gravitational waves and short gamma-ray bursts from binary mergers involving neutron stars. Such gravitational waves are highly left or right circularly polarized due to the geometry of the merger. Using localization information from the gamma-ray burst, ground-based gravitational wave detectors can measure the distance to the source with reasonable accuracy. An electromagnetic determination of the redshift from an afterglow or host galaxy yields an independent measure of this distance. Gravitational parity violation would manifest itself as a discrepancy between these two distance measurements. We exemplify such a test by considering one specific effective theory that leads to such gravitational parity violation, Chern-Simons gravity. We show that the advanced LIGO-Virgo network and all-sky gamma-ray telescopes can be sensitive to the propagating sector of Chern-Simons gravitational parity violation to a level roughly 2 orders of magnitude better than current stationary constraints from the LAGEOS satellites.

  2. Ten per cent polarized optical emission from GRB 090102.

    Science.gov (United States)

    Steele, I A; Mundell, C G; Smith, R J; Kobayashi, S; Guidorzi, C

    2009-12-10

    The nature of the jets and the role of magnetic fields in gamma-ray bursts (GRBs) remains unclear. In a baryon-dominated jet only weak, tangled fields generated in situ through shocks would be present. In an alternative model, jets are threaded with large-scale magnetic fields that originate at the central engine and that accelerate and collimate the material. To distinguish between the models the degree of polarization in early-time emission must be measured; however, previous claims of gamma-ray polarization have been controversial. Here we report that the early optical emission from GRB 090102 was polarized at 10 +/- 1 per cent, indicating the presence of large-scale fields originating in the expanding fireball. If the degree of polarization and its position angle were variable on timescales shorter than our 60-second exposure, then the peak polarization may have been larger than ten per cent.

  3. Terahertz broadband polarization converter based on metamaterials

    Science.gov (United States)

    Li, Yonghua; Zhao, Guozhong

    2018-01-01

    Based on the metamaterial composed of symmetrical split resonant ring, a broadband reflective terahertz polarization converter is proposed. The numerical simulation shows that it can rotate the polarization direction of linear polarized wave 90° in the range of 0.7-1.8THz and the polarization conversion ratio is over 90%. The reflection coefficient of the two electric field components in the diagonal direction is the same and the phase difference is 180° ,which leads to the cross-polarization rotation.In order to further study the physical mechanism of high polarization conversion, we analyze the surface current distribution of the resonant ring. The polarization converter has potential applications in terahertz wave plate and metamaterial antenna design.

  4. Gamma teletopography

    International Nuclear Information System (INIS)

    Simonet, G.

    1986-09-01

    To set the gamma activity cartography is an important element of safety in numerous cases: intervention in hot cell, search of a radioactive source, examination of radioactive waste circuit followed by a reprocessing definition of decontamination and decommissioning processes and for all other accidents. The device presented here is like a ''black box'' with an aperture and an emulsion photosensitive to the opposite; a classical film takes photography of the place; a X-ray type emulsion gives a spot more or less contrasted and extensive corresponding to each source. Images can be processed with a microprocessor [fr

  5. Polarization Measurements in Neutral Pion Photoproduction

    International Nuclear Information System (INIS)

    C. Jones; Krishni Wijesooriya; B. Fox; Andrei Afanasev; Moscov Amaryan; Konrad Aniol; Stephen Becher; Kamal Benslama; Louis Bimbot; Peter Bosted; Edward Brash; John Calarco; Zhengwei Chai; C. Chang; Ting Chang; Jian-Ping Chen; Seonho Choi; Eugene Chudakov; Steve Churchwell; Domenick Crovelli; Sonja Dieterich; Scott Dumalski; Dipangkar Dutta; Martin Epstein; Kevin Fissum; Salvatore Frullani; Haiyan Gao; Juncai Gao; Franco Garibaldi; Olivier Gayou; Ronald Gilman; Oleksandr Glamazdin; Charles Glashausser; Javier Gomez; Viktor Gorbenko; Ole Hansen; Roy Holt; Jordan Hovdebo; Garth Huber; Kees de Jager; Xiaodong Jiang; Mark Jones; Jim Kelly; Edward Kinney; Edgar Kooijman; Gerfried Kumbartzki; Michael Kuss; John LeRose; Meme Liang; Richard Lindgren; Nilanga Liyanage; Sergey Malov; Demetrius Margaziotis; Pete Markowitz; Kathy McCormick; Dave Meekins; Zein-Eddine Meziani; Robert Michaels; Joe Mitchell; Ludyvine Morand; Charles Perdrisat

    2002-01-01

    We present measurements of the recoil proton polarization for the 1 H(gamma-vector,p-vector)pi 0 reaction for theta c.m. pi = 60 o -135 o and for photon energies up to 4.1 GeV. These are the first data in this reaction for polarization transfer with circularly polarized photons. Various theoretical models are compared with the results. No evidence for hadron helicity conservation is observed. Models that employ factorization are not favored. It appears from the strong angular dependence of the induced polarization at photon energies of 2.5 and 3.1 GeV that a relatively high spin resonance or background amplitude might exist in this energy region

  6. Hyperon beams as a source of polarized protons

    International Nuclear Information System (INIS)

    Underwood, D.G.

    1978-01-01

    A high energy polarized proton beam which would utilize lambda decays as a source of polarized protons was proposed. We discuss the operation of such a beam and related physics experiments. 12 references

  7. Passive amplification of a fiber laser in a Fabry-Perot cavity: application to gamma-ray production by Compton backscattering

    International Nuclear Information System (INIS)

    Labaye, F.

    2012-01-01

    One of the critical points of the International Linear Collider (ILC) is the polarized positrons source. Without going through further explanation on the physical process of polarized positrons production, we point out that they are produced when circularly polarized gamma rays interact with mater. Thus, the critical point is the circularly polarized gamma-ray source. A technical solution for this source is the Compton backscattering and in the end, this thesis takes place in the framework for the design of a high average power laser systems enslaved to Fabry-Perot cavities for polarized gamma-ray production by Compton backscattering. In the first part, we present this thesis context, the Compton backscattering principle and the choice for an optical architecture based on a fiber laser and a Fabry-Perot cavity. We finish by enumerating several possible applications for Compton backscattering which shows that the work presented here might benefits from technology transfer through others research fields. In the second part, we present the different fiber laser architecture studied as well as the results obtained. In the third part, we remind the operating principle of a Fabry-Perot cavity and present the one used for our experiment as well as its specificities. In the fourth part, we address the Compton backscattering experiment which enables us to present the joint utilization of a fiber laser and a Fabry-Perot cavity in a particles accelerator to generate gamma rays for the first time to our knowledge. This experiment took place in the Accelerator Test Facility (ATF). The experimental apparatus as well as the results obtained are thus presented. In the end, we summarize the results presented in this manuscript and propose different evolution possibilities for the system in a general conclusion. (author)

  8. Nuclear-physical investigations with oriented nuclei and polarized neutrons

    International Nuclear Information System (INIS)

    Alfimenkov, V.P.; Pikel'ner, L.B.; Sharapov, Eh.I.

    1980-01-01

    Several experiments with oriented nuclei and polarized neutrons are considered, as well as some methods of polarization of neutrons and nuclei. Experiments on the study of spin dependence of neutron cross sections for fissionable and nonfissionable nuclei interaction of polarized neutrons with polarized nuclei as well as measurement of magnetic momenta of compound-states of rare-earth nuclei. Described are some investigations with thermal neutrons: study on spin dependence of neutron scattering length with nuclei and gamma radiation of neutron radiation capture. Difficulties of production of high-intensive polarized neutron beams and construction of oriented targets are noted. Neutron polarization by transmission of them through a polarized proton target is the most universal method (out of existing methods) in the energy range under consideration [ru

  9. Gamma knife

    International Nuclear Information System (INIS)

    Kawamoto, Shunsuke; Takakura, Kintomo

    1991-01-01

    As to the gamma knife which is the radiation surgery device developed in Sweden a quarter century ago, its principle, structure, treatment techniques, already established clinical effect and the problems being left for hereafter are described. This treatment means supplements the operation under microscopes, and at present it takes the important position in neurosurgery, but hereafter, by the interdisciplinary cooperation of neurosurgery and clinical radiobiology, the more development can be expected. The method of irradiating the radiation of high dose selectively to a target region and breaking its tissue is called radiosurgery, and the device developed for this purpose is the gamma knife. First, it was applied to functional diseases, but good results were obtained by its application to auditory nerve and brain blood vessels, and it establishes the position as the safe treatment method of the morbid state in the deep part of brains, which is difficult to reach by operation. Accompanying the recent progress of the operation of skull base part, attention is paid to its application to various tumors in skull base. On the other hand, the radiosurgery combining a cyclotron or a linear accelerator with stereotaxic brain surgery is actively tried mainly to the deformation of brain blood vessels. (K.I.)

  10. Reduction of coating induced polarization aberrations by controlling the polarization state variation

    International Nuclear Information System (INIS)

    Li, Yanghui; Shen, Weidong; Zheng, Zhenrong; Zhang, Yueguang; Liu, Xu; Hao, Xiang

    2011-01-01

    The mechanism of coating induced polarization state variation is analysed by the Jones matrix. Pauli spin matrices are used to establish the relationship between coating induced polarization state variation and polarization aberrations. To reduce coating induced polarization aberrations, we propose that δ = 0 and T s = T p at arbitrary incident angle should be appended as two additional optimization goals of optical coating design when the requirements of transmittance are met. Two typical anti-reflection (AR) coatings are designed and the polarization state variation induced by them is simulated. The MTF (modulation transfer function) calculated by polarization ray tracing is applied to evaluate the polarization aberrations of the practical lithography objective system with the two AR coatings. All the obtained results show that the coating induced polarization aberrations can be reduced by optimizing the angle dependent properties of the optical coating without additional optical elements

  11. Nuclear polarization and neutrons

    International Nuclear Information System (INIS)

    Glaettli, H.

    1985-01-01

    Different possibilities for the use of polarized nuclei in thermal neutron scattering on condensed matter are reviewed. Highly polarized nuclei are the starting point for studying dipolar magnetic order. Systematic measurement of spin-dependent scattering lengths is possible on samples with polarized nuclei. Highly polarized hydrogen should help to unravel complicated structures in chemistry and biology. The use of polarized proton targets as an energy-independent neutron polarizer in the thermal and epithermal region should be considered afresh. (author)

  12. PEPSI — a Monte Carlo generator for polarized leptoproduction

    Science.gov (United States)

    Mankiewicz, L.; Schäfer, A.; Veltri, M.

    1992-09-01

    We describe PEPSI (Polarized Electron Proton Scattering Interactions), a Monte Carlo program for polarized deep inelastic leptoproduction mediated by electromagnetic interaction, and explain how to use it. The code is a modification of the LEPTO 4.3 Lund Monte Carlo for unpolarized scattering. The hard virtual gamma-parton scattering is generated according to the polarization-dependent QCD cross-section of the first order in α S. PEPSI requires the standard polarization-independent JETSET routines to simulate the fragmentation into final hadrons.

  13. PEPSI - a Monte Carlo generator for polarized leptoproduction

    International Nuclear Information System (INIS)

    Mankiewicz, L.

    1992-01-01

    We describe PEPSI (Polarized Electron Proton Scattering Interactions) a Monte Carlo program for polarized deep inelastic leptoproduction mediated by electromagnetic interaction, and explain how to use it. The code is a modification of the Lepto 4.3 Lund Monte Carlo for unpolarized scattering. The hard virtual gamma-parton scattering is generated according to the polarization-dependent QCD cross-section of the first order in α S . PEPSI requires the standard polarization-independent JETSET routines to simulate the fragmentation into final hadrons. (orig.)

  14. Gamma rays for pedestrians

    International Nuclear Information System (INIS)

    Lipkin, H.J.

    1987-01-01

    Nuclear gamma radiation does not have many of the properties taken for granted in atomic or molecular radiation and necessary for lasers. The basic science and technology underlying these differences and the proposed methods of overcoming difficulties resulting from them are not properly understood. Considerable illumination in this interdisciplinary problem could be provided by some back-of-the-envelope calculations and simple experimental surveys by small groups of students and postdocs with an elementary knowledge of the nuclear and solid state physics which is evidently not familiar these days to laser physicists. 3 refs

  15. Atypical Laterality of Resting Gamma Oscillations in Autism Spectrum Disorders

    Science.gov (United States)

    Maxwell, Christina R.; Villalobos, Michele E.; Schultz, Robert T.; Herpertz-Dahlmann, Beate; Konrad, Kerstin; Kohls, Gregor

    2015-01-01

    Abnormal brain oscillatory activity has been found in autism spectrum disorders (ASD) and proposed as a potential biomarker. While several studies have investigated gamma oscillations in ASD, none have examined resting gamma power across multiple brain regions. This study investigated resting gamma power using EEG in 15 boys with ASD and 18 age…

  16. Specific gamma-hydroxybutyrate-binding sites but loss of pharmacological effects of gamma-hydroxybutyrate in GABA-B1-deficient mice

    DEFF Research Database (Denmark)

    Kaupmann, Klemens; Cryan, John F; Wellendorph, Petrine

    2003-01-01

    gamma-Hydroxybutyrate (GHB), a metabolite of gamma-aminobutyric acid (GABA), is proposed to function as a neurotransmitter or neuromodulator. gamma-Hydroxybutyrate and its prodrug, gamma-butyrolactone (GBL), recently received increased public attention as they emerged as popular drugs of abuse. T...

  17. Compton polarimetry detection of small circularly and linearly polarized impurities in Mössbauer 8.4 keV (3/2-1/2) M1 γ-transition of {sup 169}Tm

    Energy Technology Data Exchange (ETDEWEB)

    Tsinoev, V.; Cherepanov, V.; Shuvalov, V.; Balysh, A.; Gabbasov, R., E-mail: graul@list.ru [National Research Centre “Kurchatov Institute” (Russian Federation)

    2016-12-15

    The arrangement of an experiment to detect the P−odd and P, T−odd polarized part of the Mössbauer ({sup +}3/2– {sup +}1/2) gamma transition of a deformed {sup 169}Tm nucleus with an energy of 8.4 keV by Compton polarimetry is discussed. Tm {sub 2}O{sub 3} single crystal with a quadrupolarly split Mössbauer spectrum is proposed as a resonance polarizer. A Be-scatterer-based Compton polarimeter and a synchronously detecting system will be used to measure the P-odd circular polarization P{sub C}and P, T-odd linear polarization P{sub L}.The expected accuracy of measuring the relative magnitude of the P, T-odd contribution is about 1% of the magnitude of usual weak nucleon–nucleon interaction.

  18. Design of a tensor polarized deuterium target polarized by spin-exchange with optically pumped NA

    International Nuclear Information System (INIS)

    Green, M.C.

    1984-01-01

    A proposed design for a tensor polarized deuterium target (approx. 10 15 atoms/cm 2 ) for nuclear physics studies in an electron storage ring accelerator is presented. The deuterium atoms undergo electron spin exchange with a highly polarized sodium vapor; this polarization is transferred to the deuterium nuclei via the hyperfine interaction. The deuterium nuclei obtain their tensor polarization through repeated electron spin exchange/hyperfine interactions. The sodium vapor polarization is maintained by standard optical pumping techniques. Model calculations are presented in detail leading to a discussion of the expected performance and the technical obstacles to be surmounted in the development of such a target

  19. Design of a tensor polarized deuterium target polarized by spin-exchange with optically pumped NA

    International Nuclear Information System (INIS)

    Green, M.C.

    1984-05-01

    A proposed design for a tensor polarized deuterium target (approx. 10 15 atoms/cm 2 ) for nuclear physics studies in an electron storage ring accelerator is presented. The deuterium atoms undergo electron spin exchange with a highly polarized sodium vapor; this polarization is transferred to the deuterium nuclei via the hyperfine interaction. The deuterium nuclei obtain their tensor polarization through repeated electron spin exchange/hyperfine interactions. The sodium vapor polarization is maintained by standard optical pumping techniques. Model calculations are presented in detail leading to a discussion of the expected performance and the technical obstacles to be surmounted in the development of such a target. 15 references, 10 figures

  20. Polarized photon facilities - windows to new physics

    International Nuclear Information System (INIS)

    Sandorfi, A.M.

    1995-01-01

    The status of new and proposed sources of intermediate-energy polarized photons is reviewed. The N → δ transition is discussed as an example of new physics that can be addressed at these facilities through precision measurements of polarization observables

  1. Neutron polarization in polarized 3He targets

    International Nuclear Information System (INIS)

    Friar, J.L.; Gibson, B.F.; Payne, G.L.; Bernstein, A.M.; Chupp, T.E.

    1990-01-01

    Simple formulas for the neutron and proton polarizations in polarized 3 He targets are derived assuming (1) quasielastic final states; (2) no final-state interactions; (3) no meson-exchange currents; (4) large momentum transfers; (5) factorizability of 3 He SU(4) response-function components. Numerical results from a wide variety of bound-state solutions of the Faddeev equations are presented. It is found that this simple model predicts the polarization of neutrons in a fully polarized 3 He target to be 87%, while protons should have a slight residual polarization of -2.7%. Numerical studies show that this model works very well for quasielastic electron scattering

  2. The B-10((p)over-right-arrow, gamma)C-11 reaction at astrophysically relevant energies

    NARCIS (Netherlands)

    Tonchev, AP; Nelson, SO; Sabourov, K; Crowley, BT; Joshi, K; Weller, HR; Kelley, JH; Prior, RM; Spraker, M; Kalantar-Nayestanaki, N

    2003-01-01

    The B-10(, gamma)C-11 reaction was studied by detecting the gamma-rays produced when 100, 130-, and 160-keV polarized protons were stopped in a thick B-10 target. Polarized and unpolarized incident beams were used to measure the cross section and vector analyzing power as a function of angle and

  3. Gamma camera

    International Nuclear Information System (INIS)

    Tschunt, E.; Platz, W.; Baer, U.; Heinz, L.

    1978-01-01

    A gamma camera has a plurality of exchangeable collimators, one of which is mounted in the ray inlet opening of the camera, while the others are placed on separate supports. The supports are swingably mounted upon a column one above the other through about 90 0 to a collimator exchange position. Each of the separate supports is swingable to a vertically aligned position, with limiting of the swinging movement and positioning of the support at the desired exchange position. The collimators are carried on the supports by means of a series of vertically disposed coil springs. Projections on the camera are movable from above into grooves of the collimator at the exchange position, whereupon the collimator is turned so that it is securely prevented from falling out of the camera head

  4. Polarization Properties of 24 Fermi-Detected Blazars

    Science.gov (United States)

    Linford, Justin; Taylor, G. B.; Schinzel, F. K.; Zavala, R. T.

    2013-01-01

    Gamma-ray emitting blazars have been shown to frequently have significant polarization at radio wavelengths. In early 2012, we obtained Very Long Baseline Array (VLBA) observations of 24 blazars detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. These observations utilized the new 2 gigabit-per-second mode of the VLBA. We observed each source with full polarization at 8.4 GHz, 15 GHz, and 22 GHz with 256 MHz of total bandwidth per polarization. Our sample contains 14 flat-spectrum radio quasars (FSRQs) and 10 BL Lacertae objects (BL Lacs). We analyze the spectral index, rotation measure, and magnetic field structures of these 24 gamma-ray loud blazars.

  5. Physics results with polarized electrons at SLAC

    International Nuclear Information System (INIS)

    Prescott, C.Y.

    1996-03-01

    Polarized electron beams can play an important role in the dynamics of interactions at high energies. Polarized electron beams at SLAC have been an important part of the physics program since 1970, when they were first proposed for use in testing the spin structure of the proton. Since 1992, the SLAC linear accelerator and the SLC have operated solely with polarized electrons, providing data for tests of QCD in studies of the spin structure of the nucleon and tests of the electroweak sector of the Standard Model. In the following sections, the performance of the source is summarized, and some of the recent results using the polarized beams are discussed

  6. Sources of polarized negative ions: progress and prospects

    International Nuclear Information System (INIS)

    Haeberli, W.

    1980-01-01

    A summary of recent progress in the art of producing beams of polarized ions is given. In all sources of polarized ions, one first produces (or selects) neutral atoms which are polarized in electron spin. Those types of sources which use a beam of thermal polarized hydrogen atoms are discussed. Progress made in the preparation of the atomic beam and the methods used to convert the neutral atoms to polarized ions is summarized. The second type of source discussed is based on fast (keV) polarized hydrogen atoms. Conversion to negative ions is very simple because one only needs to pass the fast atoms through a suitable charge exchange medium (gas or vapor). However, the production of the polarized atoms is more difficult in this case. The proposal to employ polarized alkali vapor to form a beam of polarized fast H atoms, where the polarized alkali atoms are produced either by an atomic beam apparatus or by optical pumping is discussed

  7. Polarized electron sources

    International Nuclear Information System (INIS)

    Prepost, R.

    1994-01-01

    The fundamentals of polarized electron sources are described with particular application to the Stanford Linear Accelerator Center. The SLAC polarized electron source is based on the principle of polarized photoemission from Gallium Arsenide. Recent developments using epitaxially grown, strained Gallium Arsenide cathodes have made it possible to obtain electron polarization significantly in excess of the conventional 50% polarization limit. The basic principles for Gallium and Arsenide polarized photoemitters are reviewed, and the extension of the basic technique to strained cathode structures is described. Results from laboratory measurements of strained photocathodes as well as operational results from the SLAC polarized source are presented

  8. Polarized electron sources

    Energy Technology Data Exchange (ETDEWEB)

    Prepost, R. [Univ. of Wisconsin, Madison, WI (United States)

    1994-12-01

    The fundamentals of polarized electron sources are described with particular application to the Stanford Linear Accelerator Center. The SLAC polarized electron source is based on the principle of polarized photoemission from Gallium Arsenide. Recent developments using epitaxially grown, strained Gallium Arsenide cathodes have made it possible to obtain electron polarization significantly in excess of the conventional 50% polarization limit. The basic principles for Gallium and Arsenide polarized photoemitters are reviewed, and the extension of the basic technique to strained cathode structures is described. Results from laboratory measurements of strained photocathodes as well as operational results from the SLAC polarized source are presented.

  9. Some polarization features of solar microwave bursts

    Energy Technology Data Exchange (ETDEWEB)

    Uralov, A M; Nefed' ev, V P [AN SSSR, Irkutsk. Sibirskij Inst. Zemnogo Magnetizma Ionosfery i Rasprostraneniya Radiovoln

    1977-01-01

    Consequences of the thermal microwave burst model proposed earlier have been considered. According to the model the centimeter burst is generated at the heat propagation to the upper atmosphere. The polarization features of the burst are explained: a change of the polarization sign in a frequency range, a rapid change of the polarization sign in the development of a burst at a fixed frequency, a lack of time coincidence of the moments of the burst maximum of the polarization and of the total flux. From the model the consequences are obtained, which are still not confirmed by experiment. An ordinary-type wave prevails in the burst radiation, in the course of which the polarization degree falls on the ascending branch of bursts development. At the change of the polarization sign at the fixed frequency prior to the sign change an ordinary-type wave should be present in excess and later an extreordinary type wave.

  10. Oocytes Polar Body Detection for Automatic Enucleation

    Directory of Open Access Journals (Sweden)

    Di Chen

    2016-02-01

    Full Text Available Enucleation is a crucial step in cloning. In order to achieve automatic blind enucleation, we should detect the polar body of the oocyte automatically. The conventional polar body detection approaches have low success rate or low efficiency. We propose a polar body detection method based on machine learning in this paper. On one hand, the improved Histogram of Oriented Gradient (HOG algorithm is employed to extract features of polar body images, which will increase success rate. On the other hand, a position prediction method is put forward to narrow the search range of polar body, which will improve efficiency. Experiment results show that the success rate is 96% for various types of polar bodies. Furthermore, the method is applied to an enucleation experiment and improves the degree of automatic enucleation.

  11. Coherent active polarization control without loss

    Science.gov (United States)

    Ye, Yuqian; Hay, Darrick; Shi, Zhimin

    2017-11-01

    We propose a lossless active polarization control mechanism utilizing an anisotropic dielectric medium with two coherent inputs. Using scattering matrix analysis, we derive analytically the required optical properties of the anisotropic medium that can behave as a switchable polarizing beam splitter. We also show that such a designed anisotropic medium can produce linearly polarized light at any azimuthal direction through coherent control of two inputs with a specific polarization state. Furthermore, we present a straightforward design-on-demand procedure of a subwavelength-thick metastructure that can possess the desired optical anisotropy at a flexible working wavelength. Our lossless coherent polarization control technique may lead to fast, broadband and integrated polarization control elements for applications in imaging, spectroscopy, and telecommunication.

  12. Coherent active polarization control without loss

    Directory of Open Access Journals (Sweden)

    Yuqian Ye

    2017-11-01

    Full Text Available We propose a lossless active polarization control mechanism utilizing an anisotropic dielectric medium with two coherent inputs. Using scattering matrix analysis, we derive analytically the required optical properties of the anisotropic medium that can behave as a switchable polarizing beam splitter. We also show that such a designed anisotropic medium can produce linearly polarized light at any azimuthal direction through coherent control of two inputs with a specific polarization state. Furthermore, we present a straightforward design-on-demand procedure of a subwavelength-thick metastructure that can possess the desired optical anisotropy at a flexible working wavelength. Our lossless coherent polarization control technique may lead to fast, broadband and integrated polarization control elements for applications in imaging, spectroscopy, and telecommunication.

  13. Pulsar Polar Cap and Slot Gap Models: Confronting Fermi Data

    Science.gov (United States)

    Harding, Alice K.

    2012-01-01

    Rotation-powered pulsars are excellent laboratories for studying particle acceleration as well as fundamental physics of strong gravity, strong magnetic fields and relativity. I will review acceleration and gamma-ray emission from the pulsar polar cap and slot gap. Predictions of these models can be tested with the data set on pulsars collected by the Large Area Telescope on the Fermi Gamma-Ray Telescope over the last four years, using both detailed light curve fitting and population synthesis.

  14. Polarized neutron spectrometer

    International Nuclear Information System (INIS)

    Abov, Yu.G.; Novitskij, V.V.; Alfimenkov, V.P.; Galinskij, E.M.; Mareev, Yu.D.; Pikel'ner, L.B.; Chernikov, A.N.; Lason', L.; Tsulaya, V.M.; Tsulaya, M.I.

    2000-01-01

    The polarized neutron spectrometer, intended for studying the interaction of polarized neutrons with nuclei and condensed media in the area of energies from thermal up to several electron-volt, is developed at the IBR-2 reactor (JINR, Dubna). Diffraction on the Co(92%)-Fe(8%) magnetized monocrystals is used for the neutron polarization and polarization analysis. The neutron polarization within the whole energy range equals ∼ 95% [ru

  15. Pulsar Polar Cap and Slot Gap Models: Confronting Fermi Data

    Directory of Open Access Journals (Sweden)

    Alice K. Harding

    2013-09-01

    Full Text Available Rotation-powered pulsars are excellent laboratories for studying particle acceleration as well as fundamental physics of strong gravity, strong magnetic fields and relativity. Particle acceleration and high-energy emission from the polar caps is expected to occur in connection with electron-positron pair cascades. I will review acceleration and gamma-ray emission from the pulsar polar cap and associated slot gap. Predictions of these models can be tested with the data set on pulsars collected by the Large Area Telescope on the Fermi Gamma-Ray Telescope over the last four years, using both detailed light curve fitting, population synthesis and phase-resolved spectroscopy.

  16. Gamma camera

    International Nuclear Information System (INIS)

    Conrad, B.; Heinzelmann, K.G.

    1975-01-01

    A gamma camera is described which obviates the distortion of locating signals generally caused by the varied light conductive capacities of the light conductors in that the flow of light through each light conductor may be varied by means of a shutter. A balancing of the flow of light through each of the individual light conductors, in effect, collective light conductors may be balanced on the basis of their light conductive capacities or properties, so as to preclude a distortion of the locating signals caused by the varied light conductive properties of the light conductors. Each light conductor has associated therewith two, relative to each other, independently adjustable shutters, of which one forms a closure member and the other an adjusting shutter. In this embodiment of the invention it is thus possible to block all of the light conductors leading to a photoelectric transducer, with the exception of those light conductors which are to be balanced. The balancing of the individual light conductors may then be obtained on the basis of the output signals of the photoelectric transducer. (auth)

  17. Gamma ray generator

    Science.gov (United States)

    Firestone, Richard B; Reijonen, Jani

    2014-05-27

    An embodiment of a gamma ray generator includes a neutron generator and a moderator. The moderator is coupled to the neutron generator. The moderator includes a neutron capture material. In operation, the neutron generator produces neutrons and the neutron capture material captures at least some of the neutrons to produces gamma rays. An application of the gamma ray generator is as a source of gamma rays for calibration of gamma ray detectors.

  18. Beam dynamics in Compton ring gamma sources

    Directory of Open Access Journals (Sweden)

    Eugene Bulyak

    2006-09-01

    Full Text Available Electron storage rings of GeV energy with laser pulse stacking cavities are promising intense sources of polarized hard photons which, via pair production, can be used to generate polarized positron beams. In this paper, the dynamics of electron bunches circulating in a storage ring and interacting with high-power laser pulses is studied both analytically and by simulation. Both the common features and the differences in the behavior of bunches interacting with an extremely high power laser pulse and with a moderate pulse are discussed. Also considerations on particular lattice designs for Compton gamma rings are presented.

  19. Spin-polarized fuel in ICF pellets

    International Nuclear Information System (INIS)

    Wakuta, Yoshihisa; Emoto, Nobuya; Nakao, Yasuyuki; Honda, Takuro; Honda, Yoshinori; Nakashima, Hideki.

    1990-01-01

    The use of parallel spin-polarized DT or D 3 He fuel increases the fusion cross-section by 50%. By implosion-burn simulation for inertially confined fusion (ICF) pellets of the spin-polarized fuels, we found that the input energy requirement could be reduced by nearly a fact of two. These pellets taken up here include large-high-aspect-ratio DT target proposed in ILE Osaka University and DT ignitor/D 3 He fuel pellet proposed by our group. We also found that the polarized state could survive during the implosion-burn phase. (author)

  20. Photonic crystal based polarization insensitive flat lens

    International Nuclear Information System (INIS)

    Turduev, M; Bor, E; Kurt, H

    2017-01-01

    The paper proposes a new design of an inhomogeneous artificially created photonic crystal lens structure consisting of annular dielectric rods to efficiently focus both transverse electric and transverse magnetic polarizations of light into the same focal point. The locations of each individual cell that contains the annular dielectric rods are determined according to a nonlinear distribution function. The inner and outer radii of the annular photonic dielectric rods are optimized with respect to the polarization insensitive frequency response of the transmission spectrum of the lens structure. The physical background of the polarization insensitive focusing mechanism is investigated in both spatial and frequency domains. Moreover, polarization independent wavefront transformation/focusing has been explored in detail by investigating the dispersion relation of the structure. Corresponding phase index distribution of the lens is attained for polarization insensitive normalized frequency range of a / λ   =  0.280 and a / λ   =  0.300, where a denotes the lattice constant of the designed structure and λ denotes the wavelength of the incident light. We show the wave transformation performance and focal point movement dynamics for both polarizations of the lens structure by specially adjusting the length of the structure. The 3D finite-difference time domain numerical analysis is also performed to verifiy that the proposed design is able to focus the wave regardless of polarization into approximately the same focal point (difference between focal distances of both polarizations stays below 0.25 λ ) with an operating bandwidth of 4.30% between 1476 nm and 1541 nm at telecom wavelengths. The main superiorities of the proposed lens structure are being all dielectric and compact, and having flat front and back surfaces, rendering the proposed lens design more practical in the photonic integration process in various applications such as optical switch

  1. Serach for polarization effects in the antiproton production process

    CERN Multimedia

    It is proposed to study polarization effects in the production of antiprotons at the PS test beam line T11 at 3.5 GeV/c momentum. A polarization in the production process has never been studied but if existing it would allow for a rather simple and cheap way to generate a polarized antiproton beam with the existing facilities at CERN.

  2. A polarized beam for the M-3 line

    International Nuclear Information System (INIS)

    Underwood, D.; Colton, E.; Halpern, H.

    1978-01-01

    A beamline is proposed for polarized protons to be built in the M-3 line of the Meson Laboratory utilizing lambda decays. This beamline would provide a clean source of polarized protons or an enriched beam of antiprotons or polarized antiprotons

  3. The tagged photon beam polarization of the jet target experiment

    International Nuclear Information System (INIS)

    Bianchi, N.; Muccifora, V.

    1989-01-01

    The applicability of the residual electron selection method to the tagging method of the jet target laboratory has been studied. With this end in view the behaviour of the polarized bremsstrahlung cross section in the range considered has been analysed, while the polarization increase by means of the RES has been evaluated. The vertical conditions of the focusing of the tagging spectrometer as a function of energy have been determined. Finally the gamma beam density and the tagging efficiency have been calculated

  4. Polarized targets and beams

    International Nuclear Information System (INIS)

    Meyer, W.

    1985-01-01

    First the experimental situation of the single-pion photoproduction and the photodisintegration of the deuteron is briefly discussed. Then a description of the Bonn polarization facilities is given. The point of main effort is put on the polarized target which plays a vital role in the program. A facility for photon induced double polarization experiments at ELSA will be presented in section 4. Properties of a tensor polarized deuteron target are discussed in section 5. The development in the field of polarized targets, especially on new target materials, enables a new generation of polarized target experiments with (polarized) electrons. Some comments on the use of a polarized target in combination with electron beams will be discussed in section 6. Electron deuteron scattering from a tensor polarized deuteron target is considered and compared with other experimental possibilities. (orig./HSI)

  5. High current polarized electron source

    Science.gov (United States)

    Suleiman, R.; Adderley, P.; Grames, J.; Hansknecht, J.; Poelker, M.; Stutzman, M.

    2018-05-01

    Jefferson Lab operates two DC high voltage GaAs photoguns with compact inverted insulators. One photogun provides the polarized electron beam at the Continuous Electron Beam Accelerator Facility (CEBAF) up to 200 µA. The other gun is used for high average current photocathode lifetime studies at a dedicated test facility up to 4 mA of polarized beam and 10 mA of un-polarized beam. GaAs-based photoguns used at accelerators with extensive user programs must exhibit long photocathode operating lifetime. Achieving this goal represents a significant challenge for proposed facilities that must operate in excess of tens of mA of polarized average current. This contribution describes techniques to maintain good vacuum while delivering high beam currents, and techniques that minimize damage due to ion bombardment, the dominant mechanism that reduces photocathode yield. Advantages of higher DC voltage include reduced space-charge emittance growth and the potential for better photocathode lifetime. Highlights of R&D to improve the performance of polarized electron sources and prolong the lifetime of strained-superlattice GaAs are presented.

  6. Neutron detection gamma ray sensitivity criteria

    International Nuclear Information System (INIS)

    Kouzes, Richard T.; Ely, James H.; Lintereur, Azaree T.; Mace, Emily K.; Stephens, Daniel L.; Woodring, Mitchell L.

    2011-01-01

    The shortage of 3 He has triggered the search for effective alternative neutron detection technologies for national security and safeguards applications. Any new detection technology must satisfy two basic criteria: (1) it must meet a neutron detection efficiency requirement, and (2) it must be insensitive to gamma-ray interference at a prescribed level, while still meeting the neutron detection requirement. It is the purpose of this paper to define measureable gamma ray sensitivity criteria for neutron detectors. Quantitative requirements are specified for: intrinsic gamma ray detection efficiency and gamma ray absolute rejection. The gamma absolute rejection ratio for neutrons (GARRn) is defined, and it is proposed that the requirement for neutron detection be 0.9 3 He based neutron detector is provided showing that this technology can meet the stated requirements. Results from tests of some alternative technologies are also reported.

  7. Polarization-dependent optics using gauge-field metamaterials

    International Nuclear Information System (INIS)

    Liu, Fu; Xiao, Shiyi; Li, Jensen; Wang, Saisai; Hang, Zhi Hong

    2015-01-01

    We show that effective gauge field for photons with polarization-split dispersion surfaces, being realized using uniaxial metamaterials, can be used for polarization control with unique opportunities. The metamaterials with the proposed gauge field correspond to a special choice of eigenpolarizations on the Poincaré sphere as pseudo-spins, in contrary to those from either conventional birefringent crystals or optical active media. It gives rise to all-angle polarization control and a generic route to manipulate photon trajectories or polarizations in the pseudo-spin domain. As demonstrations, we show beam splitting (birefringent polarizer), all-angle polarization control, unidirectional polarization filter, and interferometer as various polarization control devices in the pseudo-spin domain. We expect that more polarization-dependent devices can be designed under the same framework

  8. Role of albedo from the Gamma-400 telescope calorimeter when recording the primary gamma emission.

    Science.gov (United States)

    Ginsburg, V. L.; Kurnosova, L. V.; Labensky, A. G.; Topchiev, N. P.; Fradkin, M. I.; Kaplin, V. A.; Kaplin, D. V.; Loginov, V. A.; Maklyaev, E. F.; Runtso, M. F.; Gorchakov, E. V.

    A calorimeter albedo emission affecting the Gamma-400 telescope operation is studied, when recording γ-quanta at energies from 10 to 1000 GeV. Methods for diminishing this impact on measuring data are proposed.

  9. Laser-driven polarized sources of hydrogen and deuterium

    International Nuclear Information System (INIS)

    Young, L.; Holt, R.J.; Green, M.C.; Kowalczyk, R.S.

    1988-01-01

    A novel laser-driven polarized source of hydrogen and deuterium which operates on the principle of spin exchange optical pumping is described. The advantages of this method over conventional polarized sources for internal target experiments are presented. Technological difficulties which prevent ideal source operation are outlined along with proposed solutions. At present, the laser-driven polarized hydrogen source delivers 8 /times/ 10 16 atoms/s with a polarization (P/sub z/) of 24%. 9 refs., 2 figs

  10. Gamma ray beam transmutation

    International Nuclear Information System (INIS)

    Imasaki, K.; Li, D.; Miyamoto, S.; Amano, S.; Motizuki, T.

    2007-01-01

    We have proposed a new approach to nuclear transmutation by a gamma ray beam of Compton scattered laser photon. We obtained 20 MeV gamma ray in this way to obtain transmutation rates with the giant resonance of 1 97Au and 1 29Iodine. The rate of the transmutation agreed with the theoretical calculation. Experiments on energy spectrum of positron, electron and neutron from targets were performed for the energy balance and design of the system scheme. The reaction rate was about 1.5∼4% for appropriate photon energies and neutron production rate was up to 4% in the measurements. We had stored laser photon more than 5000 times in a small cavity which implied for a significant improvement of system efficiency. Using these technologies, we have designed an actual transmutation system for 1 29Iodine which has a 16 million year's activity. In my presentation, I will address the properties of this scheme, experiments results and transmutation system for iodine transmutation

  11. Gamma-Ray Pulsars Models and Predictions

    CERN Document Server

    Harding, A K

    2001-01-01

    Pulsed emission from gamma-ray pulsars originates inside the magnetosphere, from radiation by charged particles accelerated near the magnetic poles or in the outer gaps. In polar cap models, the high energy spectrum is cut off by magnetic pair production above an energy that is dependent on the local magnetic field strength. While most young pulsars with surface fields in the range B = 10^{12} - 10^{13} G are expected to have high energy cutoffs around several GeV, the gamma-ray spectra of old pulsars having lower surface fields may extend to 50 GeV. Although the gamma-ray emission of older pulsars is weaker, detecting pulsed emission at high energies from nearby sources would be an important confirmation of polar cap models. Outer gap models predict more gradual high-energy turnovers at around 10 GeV, but also predict an inverse Compton component extending to TeV energies. Detection of pulsed TeV emission, which would not survive attenuation at the polar caps, is thus an important test of outer gap models. N...

  12. Scattering with polarized neutrons

    International Nuclear Information System (INIS)

    Schweizer, J.

    2007-01-01

    In the history of neutron scattering, it was shown very soon that the use of polarized neutron beams brings much more information than usual scattering with unpolarized neutrons. We shall develop here the different scattering methods that imply polarized neutrons: 1) polarized beams without polarization analysis, the flipping ratio method; 2) polarized beams with a uniaxial polarization analysis; 3) polarized beams with a spherical polarization analysis. For all these scattering methods, we shall give examples of the physical problems which can been solved by these methods, particularly in the field of magnetism: investigation of complex magnetic structures, investigation of spin or magnetization densities in metals, insulators and molecular compounds, separation of magnetic and nuclear scattering, investigation of magnetic properties of liquids and amorphous materials and even, for non magnetic material, separation between coherent and incoherent scattering. (author)

  13. Polarized Light Corridor Demonstrations.

    Science.gov (United States)

    Davies, G. R.

    1990-01-01

    Eleven demonstrations of light polarization are presented. Each includes a brief description of the apparatus and the effect demonstrated. Illustrated are strain patterns, reflection, scattering, the Faraday Effect, interference, double refraction, the polarizing microscope, and optical activity. (CW)

  14. Techniques in polarization physics

    International Nuclear Information System (INIS)

    Clausnitzer, G.

    1974-01-01

    A review of the current status of the technical tools necessary to perform different kinds of polarization experiments is presented, and the absolute and relative accuracy with which data can be obtained is discussed. A description of polarized targets and sources of polarized fast neutrons is included. Applications of polarization techniques to other fields is mentioned briefly. (14 figures, 3 tables, 110 references) (U.S.)

  15. Generating highly polarized nuclear spins in solution using dynamic nuclear polarization

    DEFF Research Database (Denmark)

    Wolber, J.; Ellner, F.; Fridlund, B.

    2004-01-01

    A method to generate strongly polarized nuclear spins in solution has been developed, using Dynamic Nuclear Polarization (DNP) at a temperature of 1.2K, and at a field of 3.354T, corresponding to an electron spin resonance frequency of 94GHz. Trityl radicals are used to directly polarize 13C...... and other low-γ nuclei. Subsequent to the DNP process, the solid sample is dissolved rapidly with a warm solvent to create a solution of molecules with highly polarized nuclear spins. Two main applications are proposed: high-resolution liquid state NMR with enhanced sensitivity, and the use...

  16. Instrument Performance and Simulation Verification of the POLAR Detector

    OpenAIRE

    Kole, M.; Li, Z. H.; Produit, N.; Tymieniecka, T.; Zhang, J.; Zwolinska, A.; Bao, T. W.; Bernasconi, T.; Cadoux, F.; Feng, M. Z.; Gauvin, N.; Hajdas, W.; Kong, S. W.; Li, H. C.; Li, L.

    2017-01-01

    POLAR is a new satellite-born detector aiming to measure the polarization of an unprecedented number of Gamma-Ray Bursts in the 50-500 keV energy range. The instrument, launched on-board the Tiangong-2 Chinese Space lab on the 15th of September 2016, is designed to measure the polarization of the hard X-ray flux by measuring the distribution of the azimuthal scattering angles of the incoming photons. A detailed understanding of the polarimeter and specifically of the systematic effects induce...

  17. Geographical Income Polarization

    DEFF Research Database (Denmark)

    Azhar, Hussain; Jonassen, Anders Bruun

    inter municipal income inequality. Counter factual simulations show that rising property prices to a large part explain the rise in polarization. One side-effect of polarization is tendencies towards a parallel polarization of residence location patterns, where low skilled individuals tend to live...

  18. Calculation of polarization effects

    International Nuclear Information System (INIS)

    Chao, A.W.

    1983-09-01

    Basically there are two areas of accelerator applications that involve beam polarization. One is the acceleration of a polarized beam (most likely a proton beam) in a synchrotron. Another concerns polarized beams in an electron storage ring. In both areas, numerical techniques have been very useful

  19. Electron-Spin Filters Would Offer Spin Polarization Greater than 1

    Science.gov (United States)

    Ting, David Z.

    2009-01-01

    A proposal has been made to develop devices that would generate spin-polarized electron currents characterized by polarization ratios having magnitudes in excess of 1. Heretofore, such devices (denoted, variously, as spin injectors, spin polarizers, and spin filters) have typically offered polarization ratios having magnitudes in the approximate range of 0.01 to 0.1. The proposed devices could be useful as efficient sources of spin-polarized electron currents for research on spintronics and development of practical spintronic devices.

  20. Cosmic gamma bursts

    International Nuclear Information System (INIS)

    Ehstulin, I.V.

    1980-01-01

    A brief consideration is being given to the history of cosmic gamma burst discovery and modern knowledge of their properties. The time dependence of gamma bursts is described and their possible sources are discussed

  1. Observation of neutron standing waves at total reflection by precision gamma spectroscopy

    International Nuclear Information System (INIS)

    Aksenov, V.L.; Gundorin, N.A.; Nikitenko, Yu.V.; Popov, Yu.P.; Cser, L.

    1998-01-01

    Total reflection of polarized neutrons from the layered structure glass/Fe (1000 A Angstrom)/Gd (50 A Angstrom) is investigated by registering neutrons and gamma-quanta from thermal neutron capture. The polarization ratio of gamma counts of neutron beams polarized in and opposite the direction of the magnetic field is measured. The polarization ratio is larger than unity for the neutron wavelengths λ 2.2 A Angstrom. Such behaviour of the wavelength dependence of the gamma-quanta polarization ratio points to the fact that over the surface of the Fe Layer a neutron standing wave caused by the interference of the incident neutron wave and the wave refracted from the magnetized Fe layer is formed

  2. Nature of gamma-ray burst sources

    International Nuclear Information System (INIS)

    Ventura, J.

    1983-01-01

    Observational evidence suggests that gamma ray bursts have a local galactic origin involving neutron stars. In this light we make a critical review of physics of the thermonuclear runaway model placing emphasis on self-consistency. We further show that some of the proposed models can be observationally excluded in the light of existing data from the Einstein Observatory. The possibility of gamma bursts arising in low mass binaries is finally discussed in the light of evolutionary scenarios leading to low luminosity systems

  3. Laser-Electron-Gamma-Source. Progress report, July 1986

    International Nuclear Information System (INIS)

    Dowell, D.H.; Fineman, B.; Giordano, G.; Kistner, OC.; Matone, G.; Sandorfi, A.M.; Schaerf, C.; Thorn, C.E.; Ziegler, W.

    1986-07-01

    When completed, the Laser Electron Gamma Source (LEGS) is expected to provide intense beams of monochromatic and polarized (circular or linear) gamma rays with energies up to 500 MeV. The gamma-ray beams will be produced by Compton backscattering uv laser light from the electrons circulating in a storage ring. Progress with installation of the facility is described, particularly the Ar-ion laser and tagging spectrometer. Tests of the tagging spectrometer coponents is reported, and a second laser is described for higher energy operation. Estimates are given of expected beam parameters. Experimental equipment for the planned research projects to be carried out at the LEGS facility is discussed

  4. Theoretical model of polar cap auroral arcs

    International Nuclear Information System (INIS)

    Kan, J.R.; Burke, W.J.; USAF, Bedford, MA)

    1985-01-01

    A theory of the polar cap auroral arcs is proposed under the assumption that the magnetic field reconnection occurs in the cusp region on tail field lines during northward interplanetary magnetic field (IMF) conditions. Requirements of a convection model during northward IMF are enumerated based on observations and fundamental theoretical considerations. The theta aurora can be expected to occur on the closed field lines convecting sunward in the central polar cap, while the less intense regular polar cap arcs can occur either on closed or open field lines. The dynamo region for the polar cap arcs is required to be on closed field lines convecting tailward in the plasma sheet which is magnetically connected to the sunward convection in the central polar cap. 43 references

  5. Pulsed diode source of polarized ions

    International Nuclear Information System (INIS)

    Katzenstein, J.; Rostoker, N.

    1983-01-01

    The advantages of polarized nuclei for fusion reactors have recently been described. We propose a pulsed source of polarized nuclei that consists of an ion diode with a polarized anode. With magnetic resonance techniques the nuclear spins of the protons of solid NH 3 can be made about 90 to 95% polarized. This material would be used for the anode. The diode would be pulsed with a voltage of 1-200K-volts for 1-2 μ sec. Flashover of the anode produces a surface plasma from which the polarized protons would be extracted to form a beam. Depolarization could be detected by comparing reaction cross sections and/or distribution of reaction products with similar results for unpolarized beams

  6. A simplified model of the source channel of the Leksell GammaKnife tested with PENELOPE.

    Science.gov (United States)

    Al-Dweri, Feras M O; Lallena, Antonio M; Vilches, Manuel

    2004-06-21

    Monte Carlo simulations using the code PENELOPE have been performed to test a simplified model of the source channel geometry of the Leksell GammaKnife. The characteristics of the radiation passing through the treatment helmets are analysed in detail. We have found that only primary particles emitted from the source with polar angles smaller than 3 degrees with respect to the beam axis are relevant for the dosimetry of the Gamma Knife. The photon trajectories reaching the output helmet collimators at (x, v, z = 236 mm) show strong correlations between rho = (x2 + y2)(1/2) and their polar angle theta, on one side, and between tan(-1)(y/x) and their azimuthal angle phi, on the other. This enables us to propose a simplified model which treats the full source channel as a mathematical collimator. This simplified model produces doses in good agreement with those found for the full geometry. In the region of maximal dose, the relative differences between both calculations are within 3%, for the 18 and 14 mm helmets, and 10%, for the 8 and 4 mm ones. Besides, the simplified model permits a strong reduction (larger than a factor 15) in the computational time.

  7. Circular polarization in the optical afterglow of GRB 121024A

    NARCIS (Netherlands)

    Wiersema, K.; Covino, S.; Toma, K.; van der Horst, A.J.; Varela, K.; Min, M.; Greiner, J.; Starling, R.L.C.; Tanvir, N.R.; Wijers, R.A.M.J.; Campana, S.; Curran, P.A.; Fan, Y.; Fynbo, J.P.U.; Gorosabel, J.; Gomboc, A.; Götz, D.; Hjorth, J.; Jin, Z.P.; Kobayashi, S.; Kouveliotou, C.; Mundell, C.; O’Brien, P.T.; Pian, E.; Rowlinson, A.; Russell, D.M.; Salvaterra, R.; di Serego Alighieri, S.; Tagliaferri, G.; Vergani, S.D.; Elliott, J.; Fariña, C.; Hartoog, O.E.; Karjalainen, R.; Klose, S.; Knust, F.; Levan, A.J.; Schady, P.; Sudilovsky, V.; Willingale, R.

    2014-01-01

    Gamma-ray bursts (GRBs) are most probably powered by collimated relativistic outflows (jets) from accreting black holes at cosmological distances. Bright afterglows are produced when the outflow collides with the ambient medium. Afterglow polarization directly probes the magnetic properties of the

  8. Circular polarization in the optical afterglow of GRB 121024A

    DEFF Research Database (Denmark)

    Wiersema, K.; Covino, S.; Toma, K.

    2014-01-01

    Gamma-ray bursts (GRBs) are most probably powered by collimated relativistic outflows (jets) from accreting black holes at cosmological distances. Bright afterglows are produced when the outflow collides with the ambient medium. Afterglow polarization directly probes the magnetic properties of th...

  9. Sky light polarization detection with linear polarizer triplet in light field camera inspired by insect vision.

    Science.gov (United States)

    Zhang, Wenjing; Cao, Yu; Zhang, Xuanzhe; Liu, Zejin

    2015-10-20

    Stable information of a sky light polarization pattern can be used for navigation with various advantages such as better performance of anti-interference, no "error cumulative effect," and so on. But the existing method of sky light polarization measurement is weak in real-time performance or with a complex system. Inspired by the navigational capability of a Cataglyphis with its compound eyes, we introduce a new approach to acquire the all-sky image under different polarization directions with one camera and without a rotating polarizer, so as to detect the polarization pattern across the full sky in a single snapshot. Our system is based on a handheld light field camera with a wide-angle lens and a triplet linear polarizer placed over its aperture stop. Experimental results agree with the theoretical predictions. Not only real-time detection but simple and costless architecture demonstrates the superiority of the approach proposed in this paper.

  10. Gamma ray astronomy

    International Nuclear Information System (INIS)

    Broomhead, Laurent.

    1980-01-01

    The nuclear gamma astronomy is presented, in particular the Gamma Ray Observatory, an enormous eight tonnes machine fitted with gamma telescopes, scheduled for launching around 1985. It is thereby hoped to study the natural nuclear reactions which occur when stars explode [fr

  11. Acceleration of polarized particles

    International Nuclear Information System (INIS)

    Buon, J.

    1992-05-01

    The spin kinetics of polarized beams in circular accelerators is reviewed in the case of spin-1/2 particles (electrons and protons) with emphasis on the depolarization phenomena. The acceleration of polarized proton beams in synchrotrons is described together with the cures applied to reduce depolarization, including the use of 'Siberian Snakes'. The in-situ polarization of electrons in storage rings due to synchrotron radiation is studied as well as depolarization in presence of ring imperfections. The applications of electron polarization to accurately calibrate the rings in energy and to use polarized beams in colliding-beam experiments are reviewed. (author) 76 refs., 19 figs., 1 tab

  12. Polarization digital holographic microscopy using low-cost liquid crystal polarization rotators

    Science.gov (United States)

    Dovhaliuk, Rostyslav Yu

    2018-02-01

    Polarization imaging methods are actively used to study anisotropic objects. A number of methods and systems, such as imaging polarimeters, were proposed to measure the state of polarization of light that passed through the object. Digital holographic and interferometric approaches can be used to quantitatively measure both amplitude and phase of a wavefront. Using polarization modulation optics, the measurement capabilities of such interference-based systems can be extended to measure polarization-dependent parameters, such as phase retardation. Different kinds of polarization rotators can be used to alternate the polarization of a reference beam. Liquid crystals are used in a rapidly increasing number of different optoelectronic devices. Twisted nematic liquid crystals are widely used as amplitude modulators in electronic displays and light valves or shutter glass. Such devices are of particular interest for polarization imaging, as they can be used as polarization rotators, and due to large-scale manufacturing have relatively low cost. A simple Mach-Zehnder polarized holographic setup that uses modified shutter glass as a polarization rotator is demonstrated. The suggested approach is experimentally validated by measuring retardation of quarter-wave film.

  13. Next to Leading Order QCD Corrections to Polarized $\\Lambda$ Production in DIS

    CERN Document Server

    de Florian, D

    1997-01-01

    We calculate next to leading order QCD corrections to semi-inclusive polarized deep inelastic scattering and $e^+e^-$ annihilation cross sections for processes where the polarization of the identified final-state hadron can also be determined. Using dimensional regularization and the HVBM prescription for the $\\gamma_5$ matrix, we compute corrections for different spin-dependent observables, both in the $\\overline{MS}$ and $\\overline{MS_p}$ factorization schemes, and analyse their structure. In addition to the well known corrections to polarized parton distributions, we also present those for final-state polarized fracture functions and polarized fragmentation functions, in a consistent factorization scheme.

  14. Polarization effects. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Courant, E.

    1981-01-01

    The use of polarized proton beams in ISABELLE is important for several general reasons: (1) With a single longitudinally polarized proton beam, effects involving parity violation can be identified and hence processes involving weak interactions can be separated from those involving strong and electromagnetic interactions. (2) Spin effects are important in the strong interactions and can be useful for testing QCD. The technique for obtaining polarized proton beams in ISABELLE appears promising, particularly in view of the present development of a polarized proton beam for the AGS. Projections for the luminosity in ISABELLE for collisions of polarized protons - one or both beams polarized with longitudinal or transverse polarization - range from 1/100 to 1 times the luminosity for unpolarized protons.

  15. The Physics of Polarization

    Science.gov (United States)

    Landi Degl'Innocenti, Egidio

    2015-10-01

    The introductory lecture that has been delivered at this Symposium is a condensed version of an extended course held by the author at the XII Canary Island Winter School from November 13 to November 21, 2000. The full series of lectures can be found in Landi Degl'Innocenti (2002). The original reference is organized in 20 Sections that are here itemized: 1. Introduction, 2. Description of polarized radiation, 3. Polarization and optical devices: Jones calculus and Muller matrices, 4. The Fresnel equations, 5. Dichroism and anomalous dispersion, 6. Polarization in everyday life, 7. Polarization due to radiating charges, 8. The linear antenna, 9. Thomson scattering, 10. Rayleigh scattering, 11. A digression on Mie scattering, 12. Bremsstrahlung radiation, 13. Cyclotron radiation, 14. Synchrotron radiation, 15. Polarization in spectral lines, 16. Density matrix and atomic polarization, 17. Radiative transfer and statistical equilibrium equations, 18. The amplification condition in polarized radiative transfer, and 19. Coupling radiative transfer and statistical equilibrium equations.

  16. High Intensity Polarized Electron Sources

    International Nuclear Information System (INIS)

    Poelker, Benard; Adderley, Philip; Brittian, Joshua; Clark, J.; Grames, Joseph; Hansknecht, John; McCarter, James; Stutzman, Marcy; Suleiman, Riad; Surles-law, Kenneth

    2008-01-01

    During the 1990s, at numerous facilities world wide, extensive RandD devoted to constructing reliable GaAs photoguns helped ensure successful accelerator-based nuclear and high-energy physics programs using spin polarized electron beams. Today, polarized electron source technology is considered mature, with most GaAs photoguns meeting accelerator and experiment beam specifications in a relatively trouble-free manner. Proposals for new collider facilities however, require electron beams with parameters beyond today's state-of-the-art and serve to renew interest in conducting polarized electron source RandD. And at CEBAF/Jefferson Lab, there is an immediate pressing need to prepare for new experiments that require considerably more beam current than before. One experiment in particular?Q-weak, a parity violation experiment that will look for physics beyond the Standard Model?requires 180 uA average current at polarization >80% for a duration of one year, with run-averaged helicity correlate

  17. Reactor gamma spectrometry: status

    International Nuclear Information System (INIS)

    Gold, R.; Kaiser, B.J.

    1979-01-01

    Current work is described for Compton Recoil Gamma-Ray Spectrometry including developments in experimental technique as well as recent reactor spectrometry measurements. The current status of the method is described concerning gamma spectromoetry probe design and response characteristics. Emphasis is given to gamma spectrometry work in US LWR and BR programs. Gamma spectrometry in BR environments are outlined by focussing on start-up plans for the Fast Test Reactor (FTR). Gamma spectrometry results are presented for a LWR pressure vessel mockup in the Poolside Critical Assembly (PCA) at Oak Ridge National Laboratory

  18. GammaWorkshops Proceedings

    International Nuclear Information System (INIS)

    Ramebaeck, H.; Straelberg, E.; Klemola, S.; Nielsen, Sven P.; Palsson, S.E.

    2012-01-01

    Due to a sparse interaction during the last years between practioners in gamma ray spectrometry in the Nordic countries, a NKS activity was started in 2009. This GammaSem was focused on seminars relevant to gamma spectrometry. A follow up seminar was held in 2010. As an outcome of these activities it was suggested that the 2011 meeting should be focused on practical issues, e.g. different corrections needed in gamma spectrometric measurements. This three day's meeting, GammaWorkshops, was held in September at Risoe-DTU. Experts on different topics relevant for gamma spectrometric measurements were invited to the GammaWorkshops. The topics included efficiency transfer, true coincidence summing corrections, self-attenuation corrections, measurement of natural radionuclides (natural decay series), combined measurement uncertainty calculations, and detection limits. These topics covered both lectures and practical sessions. The practical sessions included demonstrations of tools for e.g. corrections and calculations of the above meantioned topics. (Author)

  19. Workshop on polarized neutron filters and polarized pulsed neutron experiments

    International Nuclear Information System (INIS)

    Itoh, Shinichi

    2004-07-01

    The workshop was held in KEK by thirty-three participants on April 26, 2004. The polarized neutron filter method was only discussed. It consists of three parts; the first part was discussed on the polarized neutron methods, the second part on the polarized neutron experiments and the third on the pulse neutron spectrometer and polarized neutron experiments. The six papers were presented such as the polarized 3 He neutron spin filter, neutron polarization by proton polarized filter, soft master and neutron scattering, polarized neutron in solid physics, polarization experiments by chopper spectroscope and neutron polarization system in superHRPD. (S.Y.)

  20. Gamma model and its analysis for phase measuring profilometry.

    Science.gov (United States)

    Liu, Kai; Wang, Yongchang; Lau, Daniel L; Hao, Qi; Hassebrook, Laurence G

    2010-03-01

    Phase measuring profilometry is a method of structured light illumination whose three-dimensional reconstructions are susceptible to error from nonunitary gamma in the associated optical devices. While the effects of this distortion diminish with an increasing number of employed phase-shifted patterns, gamma distortion may be unavoidable in real-time systems where the number of projected patterns is limited by the presence of target motion. A mathematical model is developed for predicting the effects of nonunitary gamma on phase measuring profilometry, while also introducing an accurate gamma calibration method and two strategies for minimizing gamma's effect on phase determination. These phase correction strategies include phase corrections with and without gamma calibration. With the reduction in noise, for three-step phase measuring profilometry, analysis of the root mean squared error of the corrected phase will show a 60x reduction in phase error when the proposed gamma calibration is performed versus 33x reduction without calibration.

  1. Efficient composite broadband polarization retarders and polarization filters

    Science.gov (United States)

    Dimova, E.; Ivanov, S. S.; Popkirov, G.; Vitanov, N. V.

    2014-12-01

    A new type of broadband polarization half-wave retarder and narrowband polarization filters are described and experimentally tested. Both, the retarders and the filters are designed as composite stacks of standard optical half-wave plates, each of them twisted at specific angles. The theoretical background of the proposed optical devices was obtained by analogy with the method of composite pulses, known from the nuclear and quantum physics. We show that combining two composite filters built from different numbers and types of waveplates, the transmission spectrum is reduced from about 700 nm to about 10 nm width.We experimentally demonstrate that this method can be applied to different types of waveplates (broadband, zero-order, multiple order, etc.).

  2. Instrumentation with polarized neutrons

    International Nuclear Information System (INIS)

    Boeni, P.; Muenzer, W.; Ostermann, A.

    2009-01-01

    Neutron scattering with polarization analysis is an indispensable tool for the investigation of novel materials exhibiting electronic, magnetic, and orbital degrees of freedom. In addition, polarized neutrons are necessary for neutron spin precession techniques that path the way to obtain extremely high resolution in space and time. Last but not least, polarized neutrons are being used for fundamental studies as well as very recently for neutron imaging. Many years ago, neutron beam lines were simply adapted for polarized beam applications by adding polarizing elements leading usually to unacceptable losses in neutron intensity. Recently, an increasing number of beam lines are designed such that an optimum use of polarized neutrons is facilitated. In addition, marked progress has been obtained in the technology of 3 He polarizers and the reflectivity of large-m supermirrors. Therefore, if properly designed, only factors of approximately 2-3 in neutron intensity are lost. It is shown that S-benders provide neutron beams with an almost wavelength independent polarization. Using twin cavities, polarized beams with a homogeneous phase space and P>0.99 can be produced without significantly sacrificing intensity. It is argued that elliptic guides, which are coated with large m polarizing supermirrors, provide the highest flux.

  3. How It's Made - Polarized Proton Beam (444th Brookhaven Lecture)

    International Nuclear Information System (INIS)

    Zelenski, Anatoli

    2008-01-01

    Experiments with polarized beams at RHIC will provide fundamental tests of QCD, and the electro-weak interaction reveal the spin structure of the proton. Polarization asymmetries and parity violation are the strong signatures for identification of the fundamental processes, which are otherwise inaccessible. Such experiments require the maximum available luminosity and therefore polarization must be obtained as an extra beam quality without sacrificing intensity. There are proposals to polarize the high-energy proton beam in the storage rings by the Stern-Gerlach effect or spin-filter techniques. But so far, the only practically available option is acceleration of the polarized beam produced in the source and taking care of polarization survival during acceleration and storage. Two major innovations -- the 'Siberian Snake' technique for polarization preservation during acceleration and high current polarized proton sources make spin physics with the high-energy polarized beams feasible. The RHIC is the first high-energy collider, where the 'Siberian Snake' technique allowed of polarized proton beam acceleration up-to 250 GeV energy. The RHIC unique Optically Pumped Polarized Ion Source produces sufficient polarized beam intensity for complete saturation of the RHIC acceptance. This polarization technique is based on spin-transfer collisions between a proton or atomic hydrogen beam of a few keV beam energy and optically pumped alkali metal vapors. From the first proposal and feasibility studies to the operational source this development can be considered as example of successful unification of individual scientists ingenuity, international collaboration and modern technology application for creation of a new polarization technique, which allowed of two-to-three order of magnitude polarized beam intensity increase sufficient for loading the RHIC to its full capacity for polarization studies.

  4. Performance of wireless optical communication systems under polarization effects over atmospheric turbulence

    Science.gov (United States)

    Zhang, Jiankun; Li, Ziyang; Dang, Anhong

    2018-06-01

    It has been recntly shown that polarization state of propagation beam would suffer from polarization fluctuations due to the detrimental effects of atmospheric turbulence. This paper studies the performance of wireless optical communication (WOC) systems in the presence of polarization effect of atmosphere. We categorize the atmospheric polarization effect into polarization rotation, polarization-dependent power loss, and phase shift effect, with each effect described and modeled with the help of polarization-coherence theory and the extended Huygens-Fresnelprinciple. The channel matrices are derived to measure the cross-polarization interference of the system. Signal-to-noise ratio and bit error rate for polarization multiplexing system and polarization modulation system are obtained to assess the viability using the approach of M turbulence model. Monte Carlo simulation results show the performance of polarization based WOC systems to be degraded by atmospheric polarization effect, which could be evaluated precisely using the proposed model with given turbulent strengths.

  5. X-Ray-Driven Gamma Emission

    International Nuclear Information System (INIS)

    Carroll, J. J.; Karamian, S. A.; Rivlin, L. A.; Zadernovsky, A. A.

    2001-01-01

    X-ray-driven gamma emission describes processes that may release nuclear energy in a 'clean' way, as bursts of incoherent or coherent gamma rays without the production of radioactive by-products. Over the past decade, studies in this area, as a part of the larger field of quantum nucleonics, have gained tremendous momentum. Since 1987 it has been established that photons could trigger gamma emission from a long-lived metastable nuclear excited state of one nuclide and it appears likely that triggering in other isotopes will be demonstrated conclusively in the near future. With these experimental results have come new proposals for the creation of collective and avalanche-like incoherent gamma-ray bursts and even for the ultimate light source, a gamma-ray laser. Obviously, many applications would benefit from controlled bursts of gamma radiation, whether coherent or not. This paper reviews the experimental results and concepts for the production of gamma rays, driven by externally produced X-rays

  6. Polarised and tagged gamma-ray Ladon beams

    Energy Technology Data Exchange (ETDEWEB)

    Babusci, D [Istituto Nazionale di Fisica Nucleare, Frascati (Italy). Lab. Nazionale di Frascati

    1995-11-01

    The production of polarized and tagged gamma-ray beams by the backscattering of Laser light on the relativistic electrons circulating in storage rings is discussed. the main characteristic and the experimental results of the Ladon and LEGS beams are presented. The Graal beam is introduced.

  7. Polarised and tagged gamma-ray Ladon beams

    International Nuclear Information System (INIS)

    Babusci, D.

    1995-11-01

    The production of polarized and tagged gamma-ray beams by the backscattering of Laser light on the relativistic electrons circulating in storage rings is discussed. the main characteristic and the experimental results of the Ladon and LEGS beams are presented. The Graal beam is introduced

  8. Constraints on relativity violations from gamma-ray bursts.

    Science.gov (United States)

    Kostelecký, V Alan; Mewes, Matthew

    2013-05-17

    Tiny violations of the Lorentz symmetry of relativity and the associated discrete CPT symmetry could emerge in a consistent theory of quantum gravity such as string theory. Recent evidence for linear polarization in gamma-ray bursts improves existing sensitivities to Lorentz and CPT violation involving photons by factors ranging from ten to a million.

  9. Preliminary Analysis of Chinese GF-3 SAR Quad-Polarization Measurements to Extract Winds in Each Polarization

    Directory of Open Access Journals (Sweden)

    Lin Ren

    2017-11-01

    Full Text Available This study analyzed the noise equivalent sigma zero (NESZ and ocean wind sensitivity for Chinese C-band Gaofen-3 (GF-3 quad-polarization synthetic aperture radar (SAR measurements to facilitate further operational wind extraction from GF-3 data. Data from the GF-3 quad-polarization SAR and collocated winds from both NOAA/NCEP Global Forecast System (GFS atmospheric model and National Data Buoy Center (NDBC buoys were used in the analysis. For NESZ, the co-polarization was slightly higher compared to the cross-polarization. Regarding co-polarization and cross-polarization, NESZ was close to RadarSAT-2 and Sentinel-1 A. Wind sensitivity was analyzed by evaluating the dependence on winds in terms of normalized radar cross-sections (NRCS and polarization combinations. The closest geophysical model function (GMF and the polarization ratio (PR model to GF-3 data were determined by comparing data and the model results. The dependence of co-polarized NRCS on wind speed and azimuth angle was consistent with the proposed GMF models. The combination of CMOD5 and CMOD5.N was considered to be the closest GMF in co-polarization. The cross-polarized NRCS exhibited a strong linear relationship with moderate wind speeds higher than 4 m·s−1, but a weak correlation with the azimuth angle. The proposed model was considered as the closest GMF in cross-polarization. For polarization combinations, PR and polarization difference (PD were considered. PR increased only with the incidence angle, whereas PD increased with wind speed and varied with azimuth angle. There were three very close PR models and each can be considered as the closest. Preliminary results indicate that GF-3 quad-polarization data are valid and have the ability to extract winds in each polarization.

  10. Near stellar sources of gamma-ray bursts

    OpenAIRE

    Luchkov, B. I.; Markin, P. D.

    2012-01-01

    Correlation analysis of gamma-ray burst coordinates and nearby stars, registered on 2008-2011, revealed 5 coincidences with angular accuracy better than 0.1 degree. The random probability is $7\\times 10^{-7}$, so evidencing that coincident stars are indeed gamma-ray burst sources. The proposed method should be continued in order to provide their share in common balance of cosmic gamma-ray bursts.

  11. Multiphoton polarization Bremsstrahlung effect

    International Nuclear Information System (INIS)

    Golovinskij, P.A.

    2001-01-01

    A general approach to induced polarization effects was formulated on the basis of theory of many particles in a strong periodic field. Correlation with the perturbation theory is shown and the types of effective polarization potentials both for isolated atoms and ions, and for ions in plasma, are provided. State of art in the theory of forced polarization Bremsstrahlung effect is analyzed and some outlooks for further experimental and theoretical studies are outlined [ru

  12. Helicity Asymmetry in gamma p -> pi+ n with FROST

    International Nuclear Information System (INIS)

    Strauch, Steffen

    2012-01-01

    The main objective of the FROST experiment at Jefferson Lab is the study of baryon resonances. The polarization observable E for the reaction gamma p to pi+n has been measured as part of this program. A circularly polarized tagged photon beam with energies from 0.35 to 2.35 GeV was incident on a longitudinally polarized frozen-spin butanol target. The final-state pions were detected with the CEBAF Large Acceptance Spectrometer. Preliminary polarization data agree fairly well with present SAID and MAID partial-wave analyses at low photon energies. In most of the covered energy range, however, significant deviations are observed. These discrepancies underline the crucial importance of polarization observables to further constrain these analyses.

  13. Study on polarized optical flow algorithm for imaging bionic polarization navigation micro sensor

    Science.gov (United States)

    Guan, Le; Liu, Sheng; Li, Shi-qi; Lin, Wei; Zhai, Li-yuan; Chu, Jin-kui

    2018-05-01

    At present, both the point source and the imaging polarization navigation devices only can output the angle information, which means that the velocity information of the carrier cannot be extracted from the polarization field pattern directly. Optical flow is an image-based method for calculating the velocity of pixel point movement in an image. However, for ordinary optical flow, the difference in pixel value as well as the calculation accuracy can be reduced in weak light. Polarization imaging technology has the ability to improve both the detection accuracy and the recognition probability of the target because it can acquire the extra polarization multi-dimensional information of target radiation or reflection. In this paper, combining the polarization imaging technique with the traditional optical flow algorithm, a polarization optical flow algorithm is proposed, and it is verified that the polarized optical flow algorithm has good adaptation in weak light and can improve the application range of polarization navigation sensors. This research lays the foundation for day and night all-weather polarization navigation applications in future.

  14. Production of positive pions from polarized protons by linearly polarized photons in the energy region 300--420 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Get' man, V.A.; Gorbenko, V.G.; Grushin, V.F.; Derkach, A.Y.; Zhebrovskii, Y.V.; Karnaukhov, I.M.; Kolesnikov, L.Y.; Luchanin, A.A.; Rubashkin, A.L.; Sanin, V.M.; Sorokin, P.V.; Sporov, E.A.; Telegin, Y.N.; Shalatskii, S.V.

    1980-10-01

    A technique for measurement of the polarization observables ..sigma.., P, and T for the reaction ..gamma..p..-->..n..pi../sup +/ in a doubly polarized experiment (polarized proton target + linearly polarized photon beam) is described. Measurements of the angular distributions of these observables in the range of pion emission angles 30--150/sup 0/ are presented for four photon energies from 300 to 420 MeV. Inclusion of the new experimental data in an energy-independent multipole analysis of photoproduction from protons permits a more reliable selection of solutions to be made.

  15. Gamma ray auto absorption correction evaluation methodology

    International Nuclear Information System (INIS)

    Gugiu, Daniela; Roth, Csaba; Ghinescu, Alecse

    2010-01-01

    Neutron activation analysis (NAA) is a well established nuclear technique, suited to investigate the microstructural or elemental composition and can be applied to studies of a large variety of samples. The work with large samples involves, beside the development of large irradiation devices with well know neutron field characteristics, the knowledge of perturbing phenomena and adequate evaluation of correction factors like: neutron self shielding, extended source correction, gamma ray auto absorption. The objective of the works presented in this paper is to validate an appropriate methodology for gamma ray auto absorption correction evaluation for large inhomogeneous samples. For this purpose a benchmark experiment has been defined - a simple gamma ray transmission experiment, easy to be reproduced. The gamma ray attenuation in pottery samples has been measured and computed using MCNP5 code. The results show a good agreement between the computed and measured values, proving that the proposed methodology is able to evaluate the correction factors. (authors)

  16. Galactic structure and gamma radiation

    International Nuclear Information System (INIS)

    Casse, Michel; Cesarsky, Catherine; Paul Jacques

    1977-01-01

    A model of spiral structure of the Galaxy is outlined from radiosynchrotron and gamma observations. The most interesting observations in the galactic context, obtained by the SAS II American satellite are concerned with the distribution of the γ photoemission at energies higher than 10 8 eV, along the galactic equator. The model proposed is in quantitative agreement with the present ideas on the spiral structure of the Galaxy, the galactic magnetic field, and the confinement of cosmic rays by the magnetic field and of the magnetic field by matter. Following the American era, the European COS-B satellite opens the European phase towards an identification of the discrete gamma radiation sources [fr

  17. Polarization division multiple access with polarization modulation for LOS wireless communications

    Directory of Open Access Journals (Sweden)

    Cao Bin

    2011-01-01

    Full Text Available Abstract In this paper, we discuss a potential multiple access and modulation scheme based on polarized states (PS of electromagnetic (EM waves for line-of-sight (LOS communications. The proposed scheme is theoretic different from the existing polar modulation for EDGE and WCDMA systems. We propose the detailed bit representation (modulation and multiple access scheme using PS. Because of the inflexibility of polarization information in the time and frequency domains, as well as independence of frequency and space, the polarization information can be used independently for wireless communications, i.e., another independent resource domain that can be utilized. Due to the independence between the PS and the specific features of signals (such as waveform, bandwidth and data rate, the discussed polarization division multiple access (PDMA and polarization modulation (PM are expected to improve the spectrum utilization effectively. It is proved that the polarization filtering technique can be adopted in the PDMA-PM wireless communications to separate the multiuser signals and demodulate the bit information representing by PS for desired user. Some theoretical analysis is done to demonstrate the feasibility of the proposed scheme, and the simulation results are made to evaluate the performance of the suggested system.

  18. Airborne Laser Polarization Sensor

    Science.gov (United States)

    Kalshoven, James, Jr.; Dabney, Philip

    1991-01-01

    Instrument measures polarization characteristics of Earth at three wavelengths. Airborne Laser Polarization Sensor (ALPS) measures optical polarization characteristics of land surface. Designed to be flown at altitudes of approximately 300 m to minimize any polarizing or depolarizing effects of intervening atmosphere and to look along nadir to minimize any effects depending on look angle. Data from measurements used in conjunction with data from ground surveys and aircraft-mounted video recorders to refine mathematical models used in interpretation of higher-altitude polarimetric measurements of reflected sunlight.

  19. Polarization of Be stars

    International Nuclear Information System (INIS)

    Johns, M.W.

    1975-01-01

    Linear polarization of starlight may be produced by electron scattering in the extended atmospheres of early type stars. Techniques are investigated for the measurement and interpretation of this polarization. Polarimetric observations were made of twelve visual double star systems in which at least one member was a B type star as a means of separating the intrinsic stellar polarization from the polarization produced in the interstellar medium. Four of the double stars contained a Be star. Evidence for intrinsic polarization was found in five systems including two of the Be systems, one double star with a short period eclipsing binary, and two systems containing only normal early type stars for which emission lines have not been previously reported. The interpretation of these observations in terms of individual stellar polarizations and their wavelength dependence is discussed. The theoretical basis for the intrinsic polarization of early type stars is explored with a model for the disk-like extended atmospheres of Be stars. Details of a polarimeter for the measurement of the linear polarization of astronomical point sources are also presented with narrow band (Δ lambda = 100A) measurements of the polarization of γ Cas from lambda 4000 to lambda 5800

  20. Polarization at SLC

    International Nuclear Information System (INIS)

    Swartz, M.L.

    1988-07-01

    The SLAC Linear Collider has been designed to readily accommodate polarized electron beams. Considerable effort has been made to implement a polarized source, a spin rotation system, and a system to monitor the beam polarization. Nearly all major components have been fabricated. At the current time, several source and polarimeter components have been installed. The installation and commissioning of the entire system will take place during available machine shutdown periods as the commissioning of SLC progresses. It is expected that a beam polarization of 45% will be achieved with no loss in luminosity. 13 refs., 15 figs

  1. A simple proposal for Rayleigh's scaterring experiment

    Directory of Open Access Journals (Sweden)

    Adriano José Ortiz

    2010-03-01

    Full Text Available This work presents an alternative proposal for Rayleigh's scattering experiment presented and discussed in Krapas and Santos (2002 in this journal. Besides being simple and low-cost, the proposal suggested here is also proposing to demonstrate experimentally other physical phenomena such as polarization of light from the sky, the rainbow and reflection on non-conductive surfaces, as well as determine the direction of these biases. The polarization will be observed with the aid of Polaroid obtained from liquid crystal displays taken from damaged electronic devices and the Polaroid polarization direction will be established by the observation of Brewester's angle in reflection experiment.

  2. Imaging Polarimeter for a Sub-MeV Gamma-Ray All-sky Survey Using an Electron-tracking Compton Camera

    Energy Technology Data Exchange (ETDEWEB)

    Komura, S.; Takada, A.; Mizumura, Y.; Miyamoto, S.; Takemura, T.; Kishimoto, T.; Kubo, H.; Matsuoka, Y.; Mizumoto, T.; Nakamasu, Y.; Nakamura, K.; Oda, M.; Parker, J. D.; Sonoda, S.; Tanimori, T.; Tomono, D.; Yoshikawa, K. [Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502 (Japan); Kurosawa, S. [New Industry Creation Hatchery Center (NICHe), Tohoku University, Sendai, Miyagi, 980-8579 (Japan); Miuchi, K. [Department of Physics, Kobe University, Kobe, Hyogo, 658-8501 (Japan); Sawano, T., E-mail: komura@cr.scphys.kyoto-u.ac.jp [College of Science and Engineering, School of Mathematics and Physics, Kanazawa University, Kanazawa, Ishikawa, 920-1192 (Japan)

    2017-04-10

    X-ray and gamma-ray polarimetry is a promising tool to study the geometry and the magnetic configuration of various celestial objects, such as binary black holes or gamma-ray bursts (GRBs). However, statistically significant polarizations have been detected in few of the brightest objects. Even though future polarimeters using X-ray telescopes are expected to observe weak persistent sources, there are no effective approaches to survey transient and serendipitous sources with a wide field of view (FoV). Here we present an electron-tracking Compton camera (ETCC) as a highly sensitive gamma-ray imaging polarimeter. The ETCC provides powerful background rejection and a high modulation factor over an FoV of up to 2 π sr thanks to its excellent imaging based on a well-defined point-spread function. Importantly, we demonstrated for the first time the stability of the modulation factor under realistic conditions of off-axis incidence and huge backgrounds using the SPring-8 polarized X-ray beam. The measured modulation factor of the ETCC was 0.65 ± 0.01 at 150 keV for an off-axis incidence with an oblique angle of 30° and was not degraded compared to the 0.58 ± 0.02 at 130 keV for on-axis incidence. These measured results are consistent with the simulation results. Consequently, we found that the satellite-ETCC proposed in Tanimori et al. would provide all-sky surveys of weak persistent sources of 13 mCrab with 10% polarization for a 10{sup 7} s exposure and over 20 GRBs down to a 6 × 10{sup −6} erg cm{sup −2} fluence and 10% polarization during a one-year observation.

  3. Radio Flares from Gamma-ray Bursts

    Science.gov (United States)

    Kopač, D.; Mundell, C. G.; Kobayashi, S.; Virgili, F. J.; Harrison, R.; Japelj, J.; Guidorzi, C.; Melandri, A.; Gomboc, A.

    2015-06-01

    We present predictions of centimeter and millimeter radio emission from reverse shocks (RSs) in the early afterglows of gamma-ray bursts (GRBs) with the goal of determining their detectability with current and future radio facilities. Using a range of GRB properties, such as peak optical brightness and time, isotropic equivalent gamma-ray energy, and redshift, we simulate radio light curves in a framework generalized for any circumburst medium structure and including a parameterization of the shell thickness regime that is more realistic than the simple assumption of thick- or thin-shell approximations. Building on earlier work by Mundell et al. and Melandri et al. in which the typical frequency of the RS was suggested to lie at radio rather than optical wavelengths at early times, we show that the brightest and most distinct RS radio signatures are detectable up to 0.1-1 day after the burst, emphasizing the need for rapid radio follow-up. Detection is easier for bursts with later optical peaks, high isotropic energies, lower circumburst medium densities, and at observing frequencies that are less prone to synchrotron self-absorption effects—typically above a few GHz. Given recent detections of polarized prompt gamma-ray and optical RS emission, we suggest that detection of polarized radio/millimeter emission will unambiguously confirm the presence of low-frequency RSs at early time.

  4. RADIO FLARES FROM GAMMA-RAY BURSTS

    International Nuclear Information System (INIS)

    Kopač, D.; Mundell, C. G.; Kobayashi, S.; Virgili, F. J.; Harrison, R.; Japelj, J.; Gomboc, A.; Guidorzi, C.; Melandri, A.

    2015-01-01

    We present predictions of centimeter and millimeter radio emission from reverse shocks (RSs) in the early afterglows of gamma-ray bursts (GRBs) with the goal of determining their detectability with current and future radio facilities. Using a range of GRB properties, such as peak optical brightness and time, isotropic equivalent gamma-ray energy, and redshift, we simulate radio light curves in a framework generalized for any circumburst medium structure and including a parameterization of the shell thickness regime that is more realistic than the simple assumption of thick- or thin-shell approximations. Building on earlier work by Mundell et al. and Melandri et al. in which the typical frequency of the RS was suggested to lie at radio rather than optical wavelengths at early times, we show that the brightest and most distinct RS radio signatures are detectable up to 0.1–1 day after the burst, emphasizing the need for rapid radio follow-up. Detection is easier for bursts with later optical peaks, high isotropic energies, lower circumburst medium densities, and at observing frequencies that are less prone to synchrotron self-absorption effects—typically above a few GHz. Given recent detections of polarized prompt gamma-ray and optical RS emission, we suggest that detection of polarized radio/millimeter emission will unambiguously confirm the presence of low-frequency RSs at early time

  5. On Gamma-Ray Bursts

    CERN Document Server

    Ruffini, Remo; Bianco, Carlo Luciano; Caito, Letizia; Chardonnet, Pascal; Cherubini, Christian; Dainotti, Maria Giovanna; Fraschetti, Federico; Geralico, Andrea; Guida, Roberto; Patricelli, Barbara; Rotondo, Michael; Hernandez, Jorge Armando Rueda; Vereshchagin, Gregory; Xue, She-Sheng

    2008-01-01

    (Shortened) We show by example how the uncoding of Gamma-Ray Bursts (GRBs) offers unprecedented possibilities to foster new knowledge in fundamental physics and in astrophysics. After recalling some of the classic work on vacuum polarization in uniform electric fields by Klein, Sauter, Heisenberg, Euler and Schwinger, we summarize some of the efforts to observe these effects in heavy ions and high energy ion collisions. We then turn to the theory of vacuum polarization around a Kerr-Newman black hole, leading to the extraction of the blackholic energy, to the concept of dyadosphere and dyadotorus, and to the creation of an electron-positron-photon plasma. We then present a new theoretical approach encompassing the physics of neutron stars and heavy nuclei. It is shown that configurations of nuclear matter in bulk with global charge neutrality can exist on macroscopic scales and with electric fields close to the critical value near their surfaces. These configurations may represent an initial condition for the...

  6. Gamma Splines and Wavelets

    Directory of Open Access Journals (Sweden)

    Hannu Olkkonen

    2013-01-01

    Full Text Available In this work we introduce a new family of splines termed as gamma splines for continuous signal approximation and multiresolution analysis. The gamma splines are born by -times convolution of the exponential by itself. We study the properties of the discrete gamma splines in signal interpolation and approximation. We prove that the gamma splines obey the two-scale equation based on the polyphase decomposition. to introduce the shift invariant gamma spline wavelet transform for tree structured subscale analysis of asymmetric signal waveforms and for systems with asymmetric impulse response. Especially we consider the applications in biomedical signal analysis (EEG, ECG, and EMG. Finally, we discuss the suitability of the gamma spline signal processing in embedded VLSI environment.

  7. QCD factorizations in {gamma}*{gamma}*->{rho}{sub L}{sup 0}{rho}{sub L}{sup 0}

    Energy Technology Data Exchange (ETDEWEB)

    Pire, B. [CPHT, Unite mixte 7644 du CNRS, Ecole Polytechnique, 91128 Palaiseau (France)]. E-mail: pire@cpht.polytechnique.fr; Segond, M. [LPT, Unite mixte 8627 du CNRS, Universite Paris-Sud, 91405 Orsay (France); Szymanowski, L. [LPT, Unite mixte 8627 du CNRS, Universite Paris-Sud, 91405 Orsay (France); Universite de Liege, B-4000 Liege (Belgium); Soltan Institute for Nuclear Studies, Hoza 69, 00-681 Warsaw (Poland); Wallon, S. [LPT, Unite mixte 8627 du CNRS. , Universite Paris-Sud, 91405 Orsay (France)

    2006-08-24

    We calculate the lowest order QCD amplitude, i.e. the quark exchange contribution, to the forward production amplitude of a pair of longitudinally polarized {rho} mesons in the scattering of two virtual photons {gamma}*(Q{sub 1}){gamma}*(Q{sub 2})->{rho}{sub L}{sup 0}{rho}{sub L}{sup 0}. We show that the scattering amplitude simultaneously factorizes in two quite different ways: the part with transverse photons is described by the QCD factorization formula involving the generalized distribution amplitude of two final {rho} mesons, whereas the part with longitudinally polarized photons takes the QCD factorized form with the {gamma}{sub L}*->{rho}{sub L}{sup 0} transition distribution amplitude. Perturbative expressions for these, in general, non-perturbative functions are obtained in terms of the {rho}-meson distribution amplitude.

  8. New program and boundary plasma research in GAMMA 10 modification (GAMMA-PDX)

    International Nuclear Information System (INIS)

    Imai, Tsuyoshi

    2011-01-01

    GAMMA 10 is the world's largest tandem mirror machine. Since the incorporation of national universities in 2004, many R and D activities taking advantage of its features have been performed in GAMMA 10 to contribute to the development of thermonuclear fusion researches. In the second mid-term plan since 2010, modification of the machine has been proposed to start boundary plasma research projects. Cooperative studies with other groups in Japan on divertor plasmas and particle transports are conducted by taking advantage of the potential control ability and the availability of the hot ion flux of GAMMA 10. (J.P.N.)

  9. Polarization observables in Virtual Compton Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Doria, Luca

    2007-10-15

    Virtual Compton Scattering (VCS) is an important reaction for understanding nucleon structure at low energies. By studying this process, the generalized polarizabilities of the nucleon can be measured. These observables are a generalization of the already known polarizabilities and will permit theoretical models to be challenged on a new level. More specifically, there exist six generalized polarizabilities and in order to disentangle them all, a double polarization experiment must be performed. Within this work, the VCS reaction p(e,e'p){gamma} was measured at MAMI using the A1 Collaboration three spectrometer setup with Q{sup 2}=0.33 (GeV/c){sup 2}. Using the highly polarized MAMI beam and a recoil proton polarimeter, it was possible to measure both the VCS cross section and the double polarization observables. Already in 2000, the unpolarized VCS cross section was measured at MAMI. In this new experiment, we could confirm the old data and furthermore the double polarization observables were measured for the first time. The data were taken in five periods between 2005 and 2006. In this work, the data were analyzed to extract the cross section and the proton polarization. For the analysis, a maximum likelihood algorithm was developed together with the full simulation of all the analysis steps. The experiment is limited by the low statistics due mainly to the focal plane proton polarimeter efficiency. To overcome this problem, a new determination and parameterization of the carbon analyzing power was performed. The main result of the experiment is the extraction of a new combination of the generalized polarizabilities using the double polarization observables. (orig.)

  10. Gamma ray astronomy

    International Nuclear Information System (INIS)

    Fichtel, C.E.

    1975-01-01

    The first certain detection of celestial high energy gamma rays came from a satellite experiment flown on the third Orbiting Solar Observatory (OSO-111). A Gamma ray spark chamber telescope with substantively greater sensitivity and angular resolution (a few degrees) flown on the second Small Astronomy Satellite (SAS-II) has now provided a better picture of the gamma ray sky, and particularly the galactic plane and pulsars. This paper will summarize the present picture of gamma ray astronomy as it has developed at this conference from measurements made with experiments carried out on balloons, those remaining on the ground, and ones flown on satellites. (orig.) [de

  11. Gamma ray bursts: Current status of observations and theory

    International Nuclear Information System (INIS)

    Meegan, C.A.

    1990-04-01

    Gamma ray bursts display a wide range of temporal and spectral characteristics, but typically last several seconds and emit most of their energy in a low energy, gamma ray region. The burst sources appear to be isotropically distributed on the sky. Several lines of evidence suggest magnetic neutron stars as sources for bursts. A variety of energy sources and emission mechanisms are proposed

  12. Testing proton spin models with polarized beams

    International Nuclear Information System (INIS)

    Ramsey, G.P.

    1991-01-01

    We review models for spin-weighted parton distributions in a proton. Sum rules involving the nonsinglet components of the structure function xg 1 p help narrow the range of parameters in these models. The contribution of the γ 5 anomaly term depends on the size of the integrated polarized gluon distribution and experimental predictions depend on its size. We have proposed three models for the polarized gluon distributions, whose range is considerable. These model distributions give an overall range is considerable. These model distributions give an overall range of parameters that can be tested with polarized beam experiments. These are discussed with regard to specific predictions for polarized beam experiments at energies typical of UNK

  13. TRANSVERSELY POLARIZED Λ PRODUCTION

    International Nuclear Information System (INIS)

    BORER, D.

    2000-01-01

    Transversely polarized Λ production in hard scattering processes is discussed in terms of a leading twist T-odd fragmentation function which describes the fragmentation of an unpolarized quark into a transversely polarized Λ. We focus on the properties of this function and its relevance for the RHIC and HERMES experiments

  14. Our Polar Past

    Science.gov (United States)

    Clary, Renee; Wandersee, James

    2009-01-01

    The study of polar exploration is fascinating and offers students insights into the history, culture, and politics that affect the developing sciences at the farthest ends of Earth. Therefore, the authors think there is value in incorporating polar exploration accounts within modern science classrooms, and so they conducted research to test their…

  15. Marine polar steroids

    International Nuclear Information System (INIS)

    Stonik, Valentin A

    2001-01-01

    Structures, taxonomic distribution and biological activities of polar steroids isolated from various marine organisms over the last 8-10 years are considered. The peculiarities of steroid biogenesis in the marine biota and their possible biological functions are discussed. Syntheses of some highly active marine polar steroids are described. The bibliography includes 254 references.

  16. Polarized proton beams

    International Nuclear Information System (INIS)

    Roser, T.

    1995-01-01

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

  17. Polarization Optics in Telecommunications

    CERN Document Server

    Damask, Jay N

    2005-01-01

    The strong investments into optical telecommunications in the late 1990s resulted in a wealth of new research, techniques, component designs, and understanding of polarization effects in fiber. Polarization Optics in Telecommunications brings together recent advances in the field to create a standard, practical reference for component designers and optical fiber communication engineers. Beginning with a sound foundation in electromagnetism, the author offers a dissertation of the spin-vector formalism of polarization and the interaction of light with media. Applications discussed include optical isolators, optical circulators, fiber collimators, and a variety of applied waveplate and prism combinations. Also included in an extended discussion of polarization-mode dispersion (PMD) and polarization-dependent loss (PDL), their representation, behavior, statistical properties, and measurement. This book draws extensively from the technical and patent literature and is an up-to-date reference for researchers and c...

  18. Parallel Polarization State Generation.

    Science.gov (United States)

    She, Alan; Capasso, Federico

    2016-05-17

    The control of polarization, an essential property of light, is of wide scientific and technological interest. The general problem of generating arbitrary time-varying states of polarization (SOP) has always been mathematically formulated by a series of linear transformations, i.e. a product of matrices, imposing a serial architecture. Here we show a parallel architecture described by a sum of matrices. The theory is experimentally demonstrated by modulating spatially-separated polarization components of a laser using a digital micromirror device that are subsequently beam combined. This method greatly expands the parameter space for engineering devices that control polarization. Consequently, performance characteristics, such as speed, stability, and spectral range, are entirely dictated by the technologies of optical intensity modulation, including absorption, reflection, emission, and scattering. This opens up important prospects for polarization state generation (PSG) with unique performance characteristics with applications in spectroscopic ellipsometry, spectropolarimetry, communications, imaging, and security.

  19. High-energy gamma-ray beams from Compton-backscattered laser light

    Energy Technology Data Exchange (ETDEWEB)

    Sandorfi, A.M.; LeVine, M.J.; Thorn, C.E.; Giordano, G.; Matone, G.

    1983-01-01

    Collisions of light photons with relativistic electrons have previously been used to produce polarized ..gamma..-ray beams with modest (-10%) resolution but relatively low intensity. In contrast, the LEGS project (Laser + Electron Gamma Source) at Brookhaven will produce a very high flux (>2 x 10/sup 7/ s/sup -1/) of background-free polarized ..gamma.. rays whose energy will be determined to a high accuracy (..delta..E = 2.3 MeV). Initially, 300(420)-MeV ..gamma.. rays will be produced by backscattering uv light from the new 2.5(3.0)-GeV X-ray storage ring of the National Synchrotron Light Source (NSLS). The LEGS facility will operate as one of many passive users of the NSLS. In a later stage of the project, a Free Electron Laser is expectred to extend the ..gamma..-ray energy up to 700 MeV.

  20. New developments on the generation of arbitrary polarized radiation from insertion devices

    International Nuclear Information System (INIS)

    Elleaume, P.

    1991-01-01

    The complete description of the polarization of a beam of radiation is described in terms of the total energy and three polarization rates. The polarization characteristics from conventional undulators and wigglers is recalled. A presentation is made of some new insertion devices that were proposed and/or built to generate circular polarization and more generally to improve the control of polarization. They are the asymmetric and elliptical wigglers and the helical and crossed undulators

  1. Polarization preservation and control in a figure-8 ring

    Energy Technology Data Exchange (ETDEWEB)

    Derbenev, Yaroslav S. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Morozov, Vasiliy [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Lin, Fanglei [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Zhang, Yuhong [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Kondratenko, A. M. [GOO Zaryad, Russkaya st., 41, Novosibirsk, 630058; Kondratenko, M. A. [GOO Zaryad, Russkaya st., 41, Novosibirsk, 630058; Filatov, Yuri [Joint Inst. for Nuclear Research (JINR), Dubna (Russian Federation); GOO Zaryad, Russkaya st., 41, Novosibirsk, 630058

    2016-02-01

    We present a complete scheme for managing the polarization of ion beams in Jefferson Lab's proposed Medium-energy Electron-Ion Collider (MEIC). It provides preservation of the ion polarization during all stages of beam acceleration and polarization control in the collider's experimental straights. We discuss characteristic features of the spin motion in accelerators with Siberian snakes and in accelerators of figure-8 shape. We propose 3D spin rotators for polarization control in the MEIC ion collider ring. We provide polarization calculations in the collider with the 3D rotator for deuteron and proton beams. The main polarization control features of the figure-8 design are summarized.

  2. Method of incident low-energy gamma-ray direction reconstruction in the GAMMA-400 gamma-ray space telescope

    International Nuclear Information System (INIS)

    Kheymits, M D; Leonov, A A; Zverev, V G; Galper, A M; Arkhangelskaya, I V; Arkhangelskiy, A I; Yurkin, Yu T; Bakaldin, A V; Suchkov, S I; Topchiev, N P; Dalkarov, O D

    2016-01-01

    The GAMMA-400 gamma-ray space-based telescope has as its main goals to measure cosmic γ-ray fluxes and the electron-positron cosmic-ray component produced, theoretically, in dark-matter-particles decay or annihilation processes, to search for discrete γ-ray sources and study them in detail, to examine the energy spectra of diffuse γ-rays — both galactic and extragalactic — and to study gamma-ray bursts (GRBs) and γ-rays from the active Sun. Scientific goals of GAMMA-400 telescope require fine angular resolution. The telescope is of a pair-production type. In the converter-tracker, the incident gamma-ray photon converts into electron-positron pair in the tungsten layer and then the tracks are detected by silicon- strip position-sensitive detectors. Multiple scattering processes become a significant obstacle in the incident-gamma direction reconstruction for energies below several gigaelectronvolts. The method of utilising this process to improve the resolution is proposed in the presented work. (paper)

  3. POLARIZATION IMAGING AND SCATTERING MODEL OF CANCEROUS LIVER TISSUES

    Directory of Open Access Journals (Sweden)

    DONGZHI LI

    2013-07-01

    Full Text Available We apply different polarization imaging techniques for cancerous liver tissues, and compare the relative contrasts for difference polarization imaging (DPI, degree of polarization imaging (DOPI and rotating linear polarization imaging (RLPI. Experimental results show that a number of polarization imaging parameters are capable of differentiating cancerous cells in isotropic liver tissues. To analyze the contrast mechanism of the cancer-sensitive polarization imaging parameters, we propose a scattering model containing two types of spherical scatterers and carry on Monte Carlo simulations based on this bi-component model. Both the experimental and Monte Carlo simulated results show that the RLPI technique can provide a good imaging contrast of cancerous tissues. The bi-component scattering model provides a useful tool to analyze the contrast mechanism of polarization imaging of cancerous tissues.

  4. A high volume, batch mode {sup 129}Xe polarizer

    Energy Technology Data Exchange (ETDEWEB)

    Wojna-Pelczar, Anna, E-mail: anna.wojna.pelczar@mail.muni.cz [Central European Institute of Technology, Masaryk University, Brno (Czech Republic); Formerly: Marian Smoluchowski Institute of Physics, Jagiellonian University, Kraków (Poland); Pałasz, Tadeusz [Marian Smoluchowski Institute of Physics, Jagiellonian University, Kraków (Poland)

    2017-06-01

    Numerous designs of optical gas polarizers have been proposed, broadening possible applications of the hyperpolarized gases as contrast agents in magnetic resonance imaging. We present a home–made {sup 129}Xe polarizer based on the spin exchange optical pumping method. The polarizer operates under 1 bar of the gas mixture (at the maximum temperature of 160 °C) in a high volume optical cell (5025 cm{sup 3}). Approximately 100 cm{sup 3} of {sup 129}Xe polarized at 1.50±0.37% is produced in a single cycle of polarization. Operation under standard pressure imposes polarization transfer mainly via van der Waals molecules, resulting in the efficient spin exchange between rubidium and {sup 129}Xe atoms. The design, construction and operation of the polarizer are described in details.

  5. GammaSem Proceedings. A Nordic seminar for users of gamma spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Straalberg, E. (ed.) (Institute for Energy Technolgy (Norway)); Berg, K. (National Institute of Radiation Protection (Denmark)); Dowdall, M. (Norwegian Radiation Protection Authority (Norway)) (and others)

    2010-11-15

    The project GammaSem was proposed to the NKS in 2008. The aim of the project was to arrange two seminars for users of gamma spectrometry, in 2009 and 2010. The seminars were meant to provide a forum for discussions and sharing of information on practical issues concerning gamma spectrometry and initiate a network of gamma spectrometry users in the Nordic countries. Such a Nordic network should strengthen the collaboration between laboratories and improve all participants' competence in practical gamma spectrometry. Both seminars' focus was practical challenges met by the users themselves, rather than theoretical matters. Scientists and users of gamma spectrometry from all five Nordic countries were invited to the seminar, as well as scientist from the Baltic countries. A total of 65 people signed up for GammaSem 2010; representing 30 different universities, commercial companies, research institutes and authorities. The working group concept as presented at last year's GammaSem, has not worked out as intended. The reason for this is probably because most of the laboratories that signed up to join the working groups, signed up because they wanted to learn more about the different subjects. In combination with the fact that no funding was made available for the working groups, it was difficult to establish goals on what to achieve. None of the working groups applied for funding from the NKS (or elsewhere) to establish separate projects. There is a big need for more cooperation and for training within the field of gamma spectrometry. This fact has been proved through these two seminars, both by the many different topics that have been discussed, but also by the huge interest for participating in the suggested series of workshop. The GammaSem seminars have thus provided a much welcomed starting point for a broader Nordic collaboration. (Author)

  6. GammaSem Proceedings. A Nordic seminar for users of gamma spectrometry

    International Nuclear Information System (INIS)

    Straelberg, E.; Berg, K.; Dowdall, M.

    2010-11-01

    The project GammaSem was proposed to the NKS in 2008. The aim of the project was to arrange two seminars for users of gamma spectrometry, in 2009 and 2010. The seminars were meant to provide a forum for discussions and sharing of information on practical issues concerning gamma spectrometry and initiate a network of gamma spectrometry users in the Nordic countries. Such a Nordic network should strengthen the collaboration between laboratories and improve all participants' competence in practical gamma spectrometry. Both seminars' focus was practical challenges met by the users themselves, rather than theoretical matters. Scientists and users of gamma spectrometry from all five Nordic countries were invited to the seminar, as well as scientist from the Baltic countries. A total of 65 people signed up for GammaSem 2010; representing 30 different universities, commercial companies, research institutes and authorities. The working group concept as presented at last year's GammaSem, has not worked out as intended. The reason for this is probably because most of the laboratories that signed up to join the working groups, signed up because they wanted to learn more about the different subjects. In combination with the fact that no funding was made available for the working groups, it was difficult to establish goals on what to achieve. None of the working groups applied for funding from the NKS (or elsewhere) to establish separate projects. There is a big need for more cooperation and for training within the field of gamma spectrometry. This fact has been proved through these two seminars, both by the many different topics that have been discussed, but also by the huge interest for participating in the suggested series of workshop. The GammaSem seminars have thus provided a much welcomed starting point for a broader Nordic collaboration. (Author)

  7. Polarization in high Psub(trans) and cumulative hadron production

    International Nuclear Information System (INIS)

    Efremov, A.V.

    1978-01-01

    The final hadron polarization in the high Psub(trans) processes is analyzed in the parton hard scattering picture. Scaling assumption allows a correct qualitative description to be given for the Psub(trans)-behaviour of polarization or escape angle behaviour in cumulative production. The energy scaling and weak dependence on the beam and target type is predicted. A method is proposed for measuring the polarization of hadron jets

  8. Radially Polarized Conical Beam from an Embedded Etched Fiber

    OpenAIRE

    Kalaidji , D.; Spajer , M.; Marthouret , N.; Grosjean , T.

    2009-01-01

    International audience; We propose a method for producing a conical beam based on the lateral refraction of the TM01 mode from a two-mode fiber after chemical etching of the cladding, and for controlling its radial polarization. The whole power of the guided mode is transferred to the refracted beam with low diffraction. Polarization control by a series of azimuthal detectors and a stress controller affords the transmission of a stabilized radial polarization through an optical fiber. A solid...

  9. Multiport optical circulator by using polarizing beam splitter cubes as spatial walk-off polarizers.

    Science.gov (United States)

    Chen, Jing-Heng; Chen, Kun-Huang; Lin, Jiun-You; Hsieh, Hsiang-Yung

    2010-03-10

    Optical circulators are necessary passive devices applied in optical communication systems. In the design of optical circulators, the implementation of the function of spatial walk-off polarizers is a key technique that significantly influences the performance and cost of a device. This paper proposes a design of a multiport optical circulator by using polarizing beam splitter cubes as spatial walk-off polarizers. To show the feasibility of the design, a prototype of a six-port optical circulator was fabricated. The insertion losses are 0.94-1.49 dB, the isolations are 25-51 dB, and return losses are 27.72 dB.

  10. Optical vector network analyzer with improved accuracy based on polarization modulation and polarization pulling.

    Science.gov (United States)

    Li, Wei; Liu, Jian Guo; Zhu, Ning Hua

    2015-04-15

    We report a novel optical vector network analyzer (OVNA) with improved accuracy based on polarization modulation and stimulated Brillouin scattering (SBS) assisted polarization pulling. The beating between adjacent higher-order optical sidebands which are generated because of the nonlinearity of an electro-optic modulator (EOM) introduces considerable error to the OVNA. In our scheme, the measurement error is significantly reduced by removing the even-order optical sidebands using polarization discrimination. The proposed approach is theoretically analyzed and experimentally verified. The experimental results show that the accuracy of the OVNA is greatly improved compared to a conventional OVNA.

  11. Circular polarization analyzer with polarization tunable focusing of surface plasmon polaritons

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Sen; Zhang, Yan, E-mail: yzhang@mail.cnu.edu.cn [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); Beijing Key Laboratory for Metamaterials and Devices, and Key Laboratory of Terahertz Optoelectronics, Ministry of Education, Department of Physics, Capital Normal University, Beijing 100048 (China); Wang, Xinke [Beijing Key Laboratory for Metamaterials and Devices, and Key Laboratory of Terahertz Optoelectronics, Ministry of Education, Department of Physics, Capital Normal University, Beijing 100048 (China); Kan, Qiang [State Key Laboratory for Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Qu, Shiliang [Optoelectronics Department, Harbin Institute of Technology at Weihai, Weihai 264209 (China)

    2015-12-14

    A practical circular polarization analyzer (CPA) that can selectively focus surface plasmon polaritons (SPPs) at two separate locations, according to the helicity of the circularly polarized light, is designed and experimentally verified in the terahertz frequency range. The CPA consists of fishbone-slit units and is designed using the simulated annealing algorithm. By differentially detecting the intensities of the two SPPs focuses, the helicity of the incident circularly polarized light can be obtained and the CPA is less vulnerable to the noise of incident light. The proposed device may also have wide potential applications in chiral SPPs photonics and the analysis of chiral molecules in biology.

  12. Measurement of the G asymmetry for the {gamma}p{yields}N{pi} channels in the {delta}(1232) resonance region

    Energy Technology Data Exchange (ETDEWEB)

    Ahrens, J.; Arends, H.-J.; Beck, R.; Heid, E.; Jahn, O.; Jennewein, P.; Lang, M.; Rost, M.; Tamas, G.; Thomas, A.; Walcher, Th. [Universitaet Mainz, Institut fuer Kernphysik, Mainz (Germany); Altieri, S.; Panzeri, A.; Pinelli, T. [INFN, Pavia (Italy); Univ. di Pavia (Italy). Dipt. di Fisica Nucleare e Teorica; Annand, J.R.M.; Livingston, K.; McGeorge, J.C.; Rosner, G. [University of Glasgow, Department of Physics and Astronomy, Glasgow (United Kingdom); Braghieri, A.; Pedroni, P. [INFN, Sezione di Pavia, Pavia (Italy); d' Hose, N. [CEA Saclay, DSM/DAPNIA/SPhN, Gif-sur-Yvette Cedex (France); Dutz, H. [Universitaet Bonn, Physikalisches Institut, Bonn (Germany); Goertz, S.; Meyer, W.; Reicherz, G. [Ruhr-Universitaet Bochum, Institut fuer Experimentalphysik, Bochum (Germany); Grabmayr, P.; Krimmer, J. [Universitaet Tuebingen, Physikalisches Institut, Tuebingen (Germany); Hasegawa, S.; Horikawa, N. [Nagoya University, CIRSE, Nagoya (Japan); Holvoet, H.; Van Hoorebeke, L.; Lannoy, B.; Rostomyan, T.; Ryckbosch, D.; Vyver, R. van de [Universiteit Gent, Subatomaire en Stralingsfysica, Gent (Belgium); Iwata, T. [Nagoya University, Department of Physics, Nagoya (Japan); Kondratiev, R. [INR, Academy of Science, Moscow (Russian Federation); Preobrajenski, I. [Mainz Univ. (Germany). Inst. fuer Kernphysik; Academy of Science, Moscow (Russian Federation). INR; Schumacher, M.; Seitz, B.; Zapadtka, F. [Universitaet Goettingen, II. Physikalisches Institut, Goettingen (Germany)

    2005-10-01

    The G asymmetry of the {gamma}p{yields}N{pi} reaction has been measured for the first time for E{sub {gamma}}=340{+-}14 MeV. This observable, for which very scarce published data exist, plays an important role to disentangle the contributions of the various nucleon resonances. The experiment, performed at the Mainz microtron MAMI, used a 4{pi}-detector system, a linearly polarized, tagged photon beam, and a longitudinally polarized proton target. (orig.)

  13. Gamma tomography apparatus

    International Nuclear Information System (INIS)

    Span, F.J.

    1988-01-01

    The patent concerns a gamma tomography apparatus for medical diagnosis. The apparatus comprises a gamma scintillation camera head and a suspension system for supporting and positioning the camera head with respect for the patient. Both total body scanning and single photon emission tomography can be carried out with the apparatus. (U.K.)

  14. Gamma-sterilization

    International Nuclear Information System (INIS)

    Lindgren, E.

    1974-01-01

    The author makes a survey of his experience in sterilization and sterility control of medical products. At present three different methods are used, steamsterilization, gassterilizing and gammasterilizing. The investments and costs for gamma radiation is presented and a comparison of the costs for gamma- and gassterilization including sterility control is made. (M.S.)

  15. Gamma-ray sources

    International Nuclear Information System (INIS)

    Hermsen, W.

    1980-01-01

    Results are presented from an analysis of the celestial gamma-ray fine-scale structure based on over half of the data which may ultimately be available from the COS-B satellite. A catalogue consisting of 25 gamma-ray sources measured at energies above 100 MeV is presented. (Auth.)

  16. Gamma ray astronomy

    International Nuclear Information System (INIS)

    Hillier, R.

    1984-01-01

    The book reviews the development of gamma ray astronomy over the past twenty five years. A large section of the book is devoted to the problems of background radiation and the design of detectors. Gamma rays from the sun, the galactic disc, the galaxy, and extra galactic sources; are also discussed. (U.K.)

  17. Gamma dosimetry of high doses

    International Nuclear Information System (INIS)

    Martinez C, T.; Galvan G, A.; Canizal, G.

    1991-01-01

    The gamma dosimetry of high doses is problematic in almost all the classic dosemeters either based on the thermoluminescence, electric, chemical properties, etc., because they are saturated to very high dose and they are no longer useful. This work carries out an investigation in the interval of high doses. The solid system of heptahydrate ferrous sulfate, can be used as solid dosemeter of routine for high doses of radiation. The proposed method is simple, cheap and it doesn't require sophisticated spectrophotometers or spectrometers but expensive and not common in some laboratories

  18. M2 polarization enhances silica nanoparticle uptake by macrophages

    Directory of Open Access Journals (Sweden)

    Jessica eHoppstädter

    2015-03-01

    Full Text Available While silica nanoparticles have enabled numerous industrial and medical applications, their toxicological safety requires further evaluation. Macrophages are the major cell population responsible for nanoparticle clearance in vivo. The prevailing macrophage phenotype largely depends on the local immune status of the host. Whereas M1-polarized macrophages are considered as pro-inflammatory macrophages involved in host defense, M2 macrophages exhibit anti-inflammatory and wound-healing properties, but also promote tumor growth.We employed different models of M1 and M2 polarization: GM-CSF/LPS/IFN-gamma was used to generate primary human M1 cells and M-CSF/IL-10 to differentiate M2 monocyte-derived macrophages. PMA-differentiated THP-1 cells were polarized towards an M1 type by LPS/IFN-gamma and towards M2 by IL-10. Uptake of fluorescent silica nanoparticles (Ø 26 and 41 nm and microparticles (Ø 1.75 µm was quantified. At the concentration used (50 µg/ml, silica nanoparticles did not influence cell viability as assessed by MTT assay. Nanoparticle uptake was enhanced in M2-polarized primary human monocyte-derived macrophages compared with M1 cells, as shown by flow cytometric and microscopic approaches. In contrast, the uptake of microparticles did not differ between M1 and M2 phenotypes. M2 polarization was also associated with increased nanoparticle uptake in the macrophage-like THP-1 cell line. In accordance, in vivo polarized M2-like primary human tumor-associated macrophages (TAM obtained from lung tumors took up more nanoparticles than M1-like alveolar macrophages isolated from the surrounding lung tissue.In summary, our data indicate that the M2 polarization of macrophages promotes nanoparticle internalization. Therefore, the phenotypical differences between macrophage subsets should be taken into consideration in future investigations on nanosafety, but might also open up therapeutic perspectives allowing to specifically target M2

  19. Polar bears at risk

    Energy Technology Data Exchange (ETDEWEB)

    Norris, S.; Rosentrater, L.; Eid, P.M. [WWF International Arctic Programme, Oslo (Norway)

    2002-05-01

    Polar bears, the world's largest terrestrial carnivore, spend much of their lives on the arctic sea ice. This is where they hunt and move between feeding, denning, and resting areas. The world population, estimated at 22,000 bears, is made up of 20 relatively distinct populations varying in size from a few hundred to a few thousand animals. About 60 per cent of all polar bears are found in Canada. In general, the status of this species is stable, although there are pronounced differences between populations. Reductions in the extent and thickness of sea ice has lead the IUCN Polar Bear Specialist Group to describe climate change as one of the major threats facing polar bears today. Though the long-term effects of climate change will vary in different areas of the Arctic, impacts on the condition and reproductive success of polar bears and their prey are likely to be negative. Longer ice-free periods resulting from earlier break-up of sea ice in the spring and later formation in the fall is already impacting polar bears in the southern portions of their range. In Canada's Hudson Bay, for example, bears hunt on the ice through the winter and into early summer, after which the ice melts completely, forcing bears ashore to fast on stored fat until freeze-up in the fall. The time bears have on the ice to hunt and build up their body condition is cut short when the ice melts early. Studies from Hudson Bay show that for every week earlier that ice break-up occurs, bears will come ashore 10 kg lighter and in poorer condition. It is likely that populations of polar bears dividing their time between land and sea will be severely reduced and local extinctions may occur as greenhouse gas emissions continue to rise and sea ice melts. Expected changes in regional weather patterns will also impact polar bears. Rain in the late winter can cause maternity dens to collapse before females and cubs have departed, thus exposing occupants to the elements and to predators. Such

  20. Antiresonance induced spin-polarized current generation

    Science.gov (United States)

    Yin, Sun; Min, Wen-Jing; Gao, Kun; Xie, Shi-Jie; Liu, De-Sheng

    2011-12-01

    According to the one-dimensional antiresonance effect (Wang X R, Wang Y and Sun Z Z 2003 Phys. Rev. B 65 193402), we propose a possible spin-polarized current generation device. Our proposed model consists of one chain and an impurity coupling to the chain. The energy level of the impurity can be occupied by an electron with a specific spin, and the electron with such a spin is blocked because of the antiresonance effect. Based on this phenomenon our model can generate the spin-polarized current flowing through the chain due to different polarization rates. On the other hand, the device can also be used to measure the generated spin accumulation. Our model is feasible with today's technology.

  1. Population Studies of Radio and Gamma-Ray Pulsars

    Science.gov (United States)

    Harding, Alice K; Gonthier, Peter; Coltisor, Stefan

    2004-01-01

    Rotation-powered pulsars are one of the most promising candidates for at least some of the 40-50 EGRET unidentified gamma-ray sources that lie near the Galactic plane. Since the end of the EGRO mission, the more sensitive Parkes Multibeam radio survey has detected mere than two dozen new radio pulsars in or near unidentified EGRET sources, many of which are young and energetic. These results raise an important question about the nature of radio quiescence in gamma-ray pulsars: is the non-detection of radio emission a matter of beaming or of sensitivity? The answer is very dependent on the geometry of the radio and gamma-ray beams. We present results of a population synthesis of pulsars in the Galaxy, including for the first time the full geometry of the radio and gamma-ray beams. We use a recent empirically derived model of the radio emission and luminosity, and a gamma-ray emission geometry and luminosity derived theoretically from pair cascades in the polar slot gap. The simulation includes characteristics of eight radio surveys of the Princeton catalog plus the Parkes MB survey. Our results indicate that EGRET was capable of detecting several dozen pulsars as point sources, with the ratio of radio-loud to radio-quiet gamma-ray pulsars increasing significantly to about ten to one when the Parkes Survey is included. Polar cap models thus predict that many of the unidentified EGRET sources could be radio-loud gamma- ray pulsars, previously undetected as radio pulsars due to distance, large dispersion and lack of sensitivity. If true, this would make gamma-ray telescopes a potentially more sensitive tool for detecting distant young neutron stars in the Galactic plane.

  2. Gamma-ray bursts at high redshift

    NARCIS (Netherlands)

    Wijers, R.A.M.J.

    1999-01-01

    Gamma-ray bursts are much brighter than supernovae, and could therefore possibly probe the Universe to high redshift. The presently established GRB redshifts range from 0.83 to 5, and quite possibly even beyond that. Since most proposed mechanisms for GRB link them closely to deaths of massive

  3. Gamma ray induced synthesis of superabsorbent hydrogels

    International Nuclear Information System (INIS)

    Ramnani, S.P.; Sabharwal, S.; Rawat, K.P.; Majali, A.B.

    2000-01-01

    The synthesis of superabsorbent gel by grafting of acrylic acid on carboxymethyl cellulose has been carried out using gamma radiation. One gram of this gel absorbs and holds as high as 460 gm of water. The effect of various additives on water absorption characteristics was studied and possible applications of this gel to agriculture are proposed. (author)

  4. A simplified model of the source channel of the Leksell GammaKnife (registered) tested with PENELOPE

    International Nuclear Information System (INIS)

    Al-Dweri, Feras M O; Lallena, Antonio M; Vilches, Manuel

    2004-01-01

    Monte Carlo simulations using the code PENELOPE have been performed to test a simplified model of the source channel geometry of the Leksell GammaKnife (registered) . The characteristics of the radiation passing through the treatment helmets are analysed in detail. We have found that only primary particles emitted from the source with polar angles smaller than 3 deg. with respect to the beam axis are relevant for the dosimetry of the Gamma Knife. The photon trajectories reaching the output helmet collimators at (x, y, z = 236 mm) show strong correlations between ρ = (x 2 + y 2 ) 1/2 and their polar angle θ, on one side, and between tan -1 (y/x) and their azimuthal angle φ, on the other. This enables us to propose a simplified model which treats the full source channel as a mathematical collimator. This simplified model produces doses in good agreement with those found for the full geometry. In the region of maximal dose, the relative differences between both calculations are within 3%, for the 18 and 14 mm helmets, and 10%, for the 8 and 4 mm ones. Besides, the simplified model permits a strong reduction (larger than a factor 15) in the computational time

  5. A simplified model of the source channel of the Leksell GammaKnife (registered) tested with PENELOPE

    Energy Technology Data Exchange (ETDEWEB)

    Al-Dweri, Feras M O [Departamento de FIsica Moderna, Universidad de Granada, E-18071 Granada (Spain); Lallena, Antonio M [Departamento de FIsica Moderna, Universidad de Granada, E-18071 Granada (Spain); Vilches, Manuel [Servicio de RadiofIsica, Hospital ClInico ' San Cecilio' , Avda. Dr Oloriz, 16, E-18012 Granada (Spain)

    2004-06-21

    Monte Carlo simulations using the code PENELOPE have been performed to test a simplified model of the source channel geometry of the Leksell GammaKnife (registered) . The characteristics of the radiation passing through the treatment helmets are analysed in detail. We have found that only primary particles emitted from the source with polar angles smaller than 3 deg. with respect to the beam axis are relevant for the dosimetry of the Gamma Knife. The photon trajectories reaching the output helmet collimators at (x, y, z = 236 mm) show strong correlations between {rho} = (x{sup 2} + y{sup 2}){sup 1/2} and their polar angle {theta}, on one side, and between tan{sup -1}(y/x) and their azimuthal angle {phi}, on the other. This enables us to propose a simplified model which treats the full source channel as a mathematical collimator. This simplified model produces doses in good agreement with those found for the full geometry. In the region of maximal dose, the relative differences between both calculations are within 3%, for the 18 and 14 mm helmets, and 10%, for the 8 and 4 mm ones. Besides, the simplified model permits a strong reduction (larger than a factor 15) in the computational time.

  6. A simplified model of the source channel of the Leksell GammaKnife® tested with PENELOPE

    Science.gov (United States)

    Al-Dweri, Feras M. O.; Lallena, Antonio M.; Vilches, Manuel

    2004-06-01

    Monte Carlo simulations using the code PENELOPE have been performed to test a simplified model of the source channel geometry of the Leksell GammaKnife®. The characteristics of the radiation passing through the treatment helmets are analysed in detail. We have found that only primary particles emitted from the source with polar angles smaller than 3° with respect to the beam axis are relevant for the dosimetry of the Gamma Knife. The photon trajectories reaching the output helmet collimators at (x, y, z = 236 mm) show strong correlations between rgr = (x2 + y2)1/2 and their polar angle thgr, on one side, and between tan-1(y/x) and their azimuthal angle phgr, on the other. This enables us to propose a simplified model which treats the full source channel as a mathematical collimator. This simplified model produces doses in good agreement with those found for the full geometry. In the region of maximal dose, the relative differences between both calculations are within 3%, for the 18 and 14 mm helmets, and 10%, for the 8 and 4 mm ones. Besides, the simplified model permits a strong reduction (larger than a factor 15) in the computational time.

  7. GUIDE FOR POLARIZED NEUTRONS

    Science.gov (United States)

    Sailor, V.L.; Aichroth, R.W.

    1962-12-01

    The plane of polarization of a beam of polarized neutrons is changed by this invention, and the plane can be flipped back and forth quicitly in two directions in a trouble-free manner. The invention comprises a guide having a plurality of oppositely directed magnets forming a gap for the neutron beam and the gaps are spaced longitudinally in a spiral along the beam at small stepped angles. When it is desired to flip the plane of polarization the magnets are suitably rotated to change the direction of the spiral of the gaps. (AEC)

  8. Heidelberg polarized alkali source

    International Nuclear Information System (INIS)

    Kraemer, D.; Steffens, E.; Jaensch, H.; Philipps Universitaet, Marburg, Germany)

    1984-01-01

    A new atomic beam type polarized alkali ion source has been installed at Heidelberg. In order to improve the beam polarization considerably optical pumping is applied in combination with an adiabatic medium field transition which results in beams in single hyperfine sublevels. The m state population is determined by laser-induced fluorescence spectroscopy. Highly polarized beams (P/sub s/ > 0.9, s = z, zz) with intensities of 30 to 130 μA can be extracted for Li + and Na + , respectively

  9. Some deficiencies and solutions in gamma ray spectrometry

    International Nuclear Information System (INIS)

    Westmeier, W.

    1998-01-01

    A number of problems in high-resolution gamma ray spectrometry as well as some deficiencies of existing computer programs for the quantitative evaluation of spectra are discussed and some practical solutions are proposed. (author)

  10. An electrostatic RF modulator for Moessbauer gamma-rays

    International Nuclear Information System (INIS)

    Ognjanov, N.I.; Tsankov, L.T.; Ivanov, P.V.

    1983-01-01

    A new device is proposed for rf acoustic modulation of Moessbauer gamma-radiation, based on the principle of the electrostatic speaker. Certain features of the construction are discussed and results from tests are presented. (orig.)

  11. The representation of neutron polarization

    International Nuclear Information System (INIS)

    Byrne, J.

    1979-01-01

    Neutron beam polarization representation is discussed under the headings; transfer matrices, coherent parity violation for neutrons, neutron spin rotation in helical magnetic fields, polarization and interference. (UK)

  12. Mercuric Iodide Anticoincidence Shield for Gamma-Ray Spectrometer, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to utilize a new detector material, polycrystalline mercuric iodide, for background suppression by active anticoincidence shielding in gamma-ray...

  13. Investigation of epigenetic gene regulation in Arabidopsis modulated by gamma radiation

    International Nuclear Information System (INIS)

    Woo, Hye Ryun; Kim, Jae Sung; Lee, Myung Jin; Lee, Dong Joon; Kim, Young Min; Jung, Joon Yong; Han, Wan Keun; Kang, Soo Jin

    2011-12-01

    To investigate epigenetic gene regulation in Arabidopsis modulated by gamma radiation, we examined the changes in DNA methylation and histone modification after gamma radiation and investigated the effects of gamma radiation on epigenetic information and gene expression. We have selected 14 genes with changes in DNA methylation by gamma radiation, analyzed the changes of histone modification in the selected genes to reveal the relationship between DNA methylation and histone modification by gamma radiation. We have also analyzed the effects of gamma radiation on gene expression to investigate the relationship between epigenetic information and gene expression by gamma radiation. The results will be useful to reveal the effects of gamma radiation on DNA methylation, histone modification and gene expression. We anticipate that the information generated in this proposal will help to find out the mechanism underlying the changes in epigenetic information by gamma radiation

  14. Fluorescence confocal polarizing microscopy: Three-dimensional ...

    Indian Academy of Sciences (India)

    Much of the modern understanding of orientational order in liquid crystals (LCs) is based on polarizing microscopy (PM). A PM image bears only two-dimensional (2D) information, integrating the 3D pattern of optical birefringence over the path of light. Recently, we proposed a technique to image 3D director patterns by ...

  15. Simulation of erasure of photoinduced anisotropy by circularly polarized light

    DEFF Research Database (Denmark)

    Sajti, Sz.; Kerekes, Á.; Barabás, M.

    2001-01-01

    The temporal evolution of photoinduced birefringence is investigated on the basis of a model proposed by Pedersen and co-workers, This model is extended for the case of elliptically polarized light, and used to describe the erasure of photoinduced birefringence by circularly polarized light...

  16. Spin polarization at the interface and tunnel magnetoresistance

    International Nuclear Information System (INIS)

    Itoh, H.; Inoue, J.

    2001-01-01

    We propose that interfacial states of imperfectly oxidized Al ions may exist in ferromagnetic tunnel junctions with Al-O barrier and govern both the spin polarization and tunnel conductance. It is shown that the spin polarization is positive independent of materials and correlates well with the tunnel magnetoresistance

  17. Interferometric polarization control

    International Nuclear Information System (INIS)

    Chuss, David T.; Wollack, Edward J.; Moseley, S. Harvey; Novak, Giles

    2006-01-01

    We develop the Jones and Mueller matrices for structures that allow control of the path length difference between two linear orthogonal polarizations and consider the effect of placing multiple devices in series. Specifically, we find that full polarization modulation (measurement of Stokes Q, U, and V) can be achieved by placing two such modulators in series if the relative angles of the beam-splitting grids with respect to the analyzer orientation are appropriately chosen. Such a device has several potential advantages over a spinning wave plate modulator for measuring astronomical polarization in the far infrared through millimeter: (i) The use of small, linear motions eliminates the need for cryogenic rotational bearings; (ii) the phase flexibility allows measurement of circular as well as linear polarization; and (iii) this architecture allows for both multiwavelength and broadband modulation. We also present initial laboratory results

  18. Dynamic nuclear spin polarization

    Energy Technology Data Exchange (ETDEWEB)

    Stuhrmann, H B [GKSS-Forschungszentrum Geesthacht GmbH (Germany)

    1996-11-01

    Polarized neutron scattering from dynamic polarized targets has been applied to various hydrogenous materials at different laboratories. In situ structures of macromolecular components have been determined by nuclear spin contrast variation with an unprecedented precision. The experiments of selective nuclear spin depolarisation not only opened a new dimension to structural studies but also revealed phenomena related to propagation of nuclear spin polarization and the interplay of nuclear polarisation with the electronic spin system. The observation of electron spin label dependent nuclear spin polarisation domains by NMR and polarized neutron scattering opens a way to generalize the method of nuclear spin contrast variation and most importantly it avoids precontrasting by specific deuteration. It also likely might tell us more about the mechanism of dynamic nuclear spin polarisation. (author) 4 figs., refs.

  19. On the sum of Gamma-Gamma variates with application to the fast outage probability evaluation over fading channels

    KAUST Repository

    Ben Issaid, Chaouki; Rached, Nadhir B.; Kammoun, Abla; Alouini, Mohamed-Slim; Tempone, Raul

    2017-01-01

    The Gamma-Gamma distribution has recently emerged in a number of applications ranging from modeling scattering and reverbation in sonar and radar systems to modeling atmospheric turbulence in wireless optical channels. In this respect, assessing the outage probability achieved by some diversity techniques over this kind of channels is of major practical importance. In many circumstances, this is intimately related to the difficult question of analyzing the statistics of a sum of Gamma-Gamma random variables. Answering this question is not a simple matter. This is essentially because outage probabilities encountered in practice are often very small, and hence the use of classical Monte Carlo methods is not a reasonable choice. This lies behind the main motivation of the present work. In particular, this paper proposes a new approach to estimate the left tail of the sum of independent and identically distributed Gamma-Gamma variates. More specifically, we propose a mean-shift importance sampling scheme that efficiently evaluates the outage probability of L-branch maximum ratio combining diversity receivers over Gamma-Gamma fading channels. The proposed estimator satisfies the well-known bounded relative error criterion. We show the accuracy and the efficiency of our approach compared to naive Monte Carlo via some selected numerical simulations.

  20. On the sum of Gamma-Gamma variates with application to the fast outage probability evaluation over fading channels

    KAUST Repository

    Ben Issaid, Chaouki

    2017-04-01

    The Gamma-Gamma distribution has recently emerged in a number of applications ranging from modeling scattering and reverbation in sonar and radar systems to modeling atmospheric turbulence in wireless optical channels. In this respect, assessing the outage probability achieved by some diversity techniques over this kind of channels is of major practical importance. In many circumstances, this is intimately related to the difficult question of analyzing the statistics of a sum of Gamma-Gamma random variables. Answering this question is not a simple matter. This is essentially because outage probabilities encountered in practice are often very small, and hence the use of classical Monte Carlo methods is not a reasonable choice. This lies behind the main motivation of the present work. In particular, this paper proposes a new approach to estimate the left tail of the sum of independent and identically distributed Gamma-Gamma variates. More specifically, we propose a mean-shift importance sampling scheme that efficiently evaluates the outage probability of L-branch maximum ratio combining diversity receivers over Gamma-Gamma fading channels. The proposed estimator satisfies the well-known bounded relative error criterion. We show the accuracy and the efficiency of our approach compared to naive Monte Carlo via some selected numerical simulations.

  1. Multiband Circular Polarizer Based on Fission Transmission of Linearly Polarized Wave for X-Band Applications

    Directory of Open Access Journals (Sweden)

    Farman Ali Mangi

    2016-01-01

    Full Text Available A multiband circular polarizer based on fission transmission of linearly polarized wave for x-band application is proposed, which is constructed of 2 × 2 metallic strips array. The linear-to-circular polarization conversion is obtained by decomposing the linearly incident x-polarized wave into two orthogonal vector components of equal amplitude and 90° phase difference between them. The innovative approach of “fission transmission of linear-to-circular polarized wave” is firstly introduced to obtain giant circular dichroism based on decomposition of orthogonal vector components through the structure. It means that the incident linearly polarized wave is converted into two orthogonal components through lower printed metallic strips layer and two transmitted waves impinge on the upper printed strips layer to convert into four orthogonal vector components at the end of structure. This projection and transmission sequence of orthogonal components sustain the chain transmission of electromagnetic wave and can achieve giant circular dichroism. Theoretical analysis and microwave experiments are presented to validate the performance of the structure. The measured results are in good agreement with simulation results. In addition, the proposed circular polarizer exhibits the optimal performance with respect to the normal incidence. The right handed circularly polarized wave is emitted ranging from 10.08 GHz to 10.53 GHz and 10.78 GHz to 11.12 GHz, while the left handed circular polarized wave is excited at 10.54 GHz–10.70 GHz and 11.13 GHz–11.14 GHz, respectively.

  2. Plasma polarization spectroscopy

    International Nuclear Information System (INIS)

    Iwamae, Atsushi; Horimoto, Yasuhiro; Fujimoto, Takashi; Hasegawa, Noboru; Sukegawa, Kouta; Kawachi, Tetsuya

    2005-01-01

    The electron velocity distribution function (EVDF) in plasma can be anisotropic in laser-produced plasmas. We have developed a new technique to evaluate the polarization degree of the emission lines in the extreme vacuum ultra violet wavelength region. The polarization of the emission lines and the continuums from the lithium-like nitrogen and from helium- and hydrogen-like carbon in recombining plasma is evaluated. Particle simulation in the velocity space gives the time scale for relaxation of anisotropic EVDFs. (author)

  3. No More Polarization, Please!

    OpenAIRE

    Reinholt, Mia

    2006-01-01

    The organizational science literature on motivation has for long been polarized into two main positions; the organizational economic position focusing on extrinsic motivation and the organizational behavior position emphasizing intrinsic motivation. With the rise of the knowledge economy and the increasing levels of complexities it entails, such polarization is not fruitful in the attempt to explain motivation of organizational members. This paper claims that a more nuanced perspective on mot...

  4. Inertial polarization of dielectrics

    OpenAIRE

    Zavodovsky, A. G.

    2011-01-01

    It was proved that accelerated motion of a linear dielectric causes its polarization. Accelerated translational motion of a dielectric's plate leads to the positive charge of the surface facing the direction of motion. Metal plates of a capacitor were used to register polarized charges on a dielectric's surface. Potential difference between the capacitor plates is proportional to acceleration, when acceleration is constant potential difference grows with the increase of a dielectric's area, o...

  5. Polarized (3) He Spin Filters for Slow Neutron Physics.

    Science.gov (United States)

    Gentile, T R; Chen, W C; Jones, G L; Babcock, E; Walker, T G

    2005-01-01

    Polarized (3)He spin filters are needed for a variety of experiments with slow neutrons. Their demonstrated utility for highly accurate determination of neutron polarization are critical to the next generation of betadecay correlation coefficient measurements. In addition, they are broadband devices that can polarize large area and high divergence neutron beams with little gamma-ray background, and allow for an additional spin-flip for systematic tests. These attributes are relevant to all neutron sources, but are particularly well-matched to time of flight analysis at spallation sources. There are several issues in the practical use of (3)He spin filters for slow neutron physics. Besides the essential goal of maximizing the (3)He polarization, we also seek to decrease the constraints on cell lifetimes and magnetic field homogeneity. In addition, cells with highly uniform gas thickness are required to produce the spatially uniform neutron polarization needed for beta-decay correlation coefficient experiments. We are currently employing spin-exchange (SE) and metastability-exchange (ME) optical pumping to polarize (3)He, but will focus on SE. We will discuss the recent demonstration of 75 % (3)He polarization, temperature-dependent relaxation mechanism of unknown origin, cell development, spectrally narrowed lasers, and hybrid spin-exchange optical pumping.

  6. The McDonald exponentiated gamma distribution and its statistical properties

    OpenAIRE

    Al-Babtain, Abdulhakim A; Merovci, Faton; Elbatal, Ibrahim

    2015-01-01

    Abstract In this paper, we propose a five-parameter lifetime model called the McDonald exponentiated gamma distribution to extend beta exponentiated gamma, Kumaraswamy exponentiated gamma and exponentiated gamma, among several other models. We provide a comprehensive mathematical treatment of this distribution. We derive the moment generating function and the rth moment. We discuss estimation of the parameters by maximum likelihood and provide the information matrix. AMS Subject Classificatio...

  7. GammaWorkshops Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Ramebaeck, H. (ed.) (Swedish Defence Research Agency (Sweden)); Straalberg, E. (Institute for Energy Technology, Kjeller (Norway)); Klemola, S. (Radiation and Nuclear Safety Authority, STUK (Finland)); Nielsen, Sven P. (Technical Univ. of Denmark. Risoe National Lab. for Sustainable Energy, Roskilde (Denmark)); Palsson, S.E. (Icelandic Radiation Safety Authority (Iceland))

    2012-01-15

    Due to a sparse interaction during the last years between practioners in gamma ray spectrometry in the Nordic countries, a NKS activity was started in 2009. This GammaSem was focused on seminars relevant to gamma spectrometry. A follow up seminar was held in 2010. As an outcome of these activities it was suggested that the 2011 meeting should be focused on practical issues, e.g. different corrections needed in gamma spectrometric measurements. This three day's meeting, GammaWorkshops, was held in September at Risoe-DTU. Experts on different topics relevant for gamma spectrometric measurements were invited to the GammaWorkshops. The topics included efficiency transfer, true coincidence summing corrections, self-attenuation corrections, measurement of natural radionuclides (natural decay series), combined measurement uncertainty calculations, and detection limits. These topics covered both lectures and practical sessions. The practical sessions included demonstrations of tools for e.g. corrections and calculations of the above meantioned topics. (Author)

  8. The Polarization of Achernar

    Science.gov (United States)

    McDavid, D.

    2005-11-01

    Recent near-infrared measurements of the angular diameter of Achernar (the bright Be star alpha Eridani) with the ESO VLT interferometer have been interpreted as the detection of an extremely oblate photosphere, with a ratio of equatorial to polar radius of at least 1.56 ± 0.05 and a minor axis orientation of 39° ± 1° (from North to East). The optical linear polarization of this star during an emission phase in 1995 September was 0.12 ± 0.02% at position angle 37° ± 8° (in equatorial coordinates), which is the direction of the projection of the rotation axis on the plane of the sky according to the theory of polarization by electron scattering in an equatorially flattened circumstellar disk. These two independent determinations of the orientation of the rotation axis are therefore in agreement. The observational history of correlations between Hα emission and polarization as found in the literature is that of a typical Be star, with the exception of an interesting question raised by the contrast between Schröder's measurement of a small polarization perpendicular to the projected rotation axis in 1969--70 and Tinbergen's measurement of zero polarization in 1974.5, both at times when emission was reportedly absent.

  9. Gamma-ray pulsars: Emission zones and viewing geometries

    Science.gov (United States)

    Romani, Roger W.; Yadigaroglu, I.-A.

    1995-01-01

    There are now a half-dozen young pulsars detected in high-energy photons by the Compton Gamma-Ray Observatory (CGRO), showing a variety of emission efficiencies and pulse profiles. We present here a calculation of the pattern of high-energy emission on the sky in a model which posits gamma-ray production by charge-depleted gaps in the outer magnetosphere. This model accounts for the radio to gamma-ray pulse offsets of the known pulsars, as well as the shape of the high-energy pulse profiles. We also show that about one-third of emitting young radio pulsars will not be detected due to beaming effects, while approximately 2.5 times the number of radio-selected gamma-ray pulsars will be viewed only high energies. Finally we compute the polarization angle variation and find that the previously misunderstood optical polarization sweep of the Crab pulsar arises naturally in this picture. These results strongly support an outer magnetosphere location for the gamma-ray emission.

  10. Fusion of a polarized projectile with a polarized target

    International Nuclear Information System (INIS)

    Christley, J.A.; Johnson, R.C.; Thompson, I.J.

    1995-01-01

    The fusion cross sections for a polarized target with both unpolarized and polarized projectiles are studied. Expressions for the observables are given for the case when both nuclei are polarized. Calculations for fusion of an aligned 165 Ho target with 16 O and polarized 7 Li beams are presented

  11. Bringing Society to a Changing Polar Ocean: Polar Interdisciplinary Coordinated Education (ICE)

    Science.gov (United States)

    Schofield, O.

    2015-12-01

    Environmental changes in the Arctic and Antarctic appear to be accelerating and scientists are trying to understand both the patterns and the impacts of change. These changes will have profound impact on humanity and create a need for public education about these critical habitats. We have focused on a two-pronged strategy to increase public awareness as well as enable educators to discuss comfortably the implications of climate change. Our first focus is on entraining public support through the development of science documentaries about the science and people who conduct it. Antarctic Edge is a feature length award-winning documentary about climate change that has been released in May 2015 and has garnered interest in movie theatres and on social media stores (NetFlix, ITunes). This broad outreach is coupled with our group's interest assisting educators formally. The majority of current polar education is focused on direct educator engagement through personal research experiences that have impact on the participating educators' classrooms. Polar Interdisciplinary Coordinated Education (ICE) proposes to improve educator and student engagement in polar sciences through exposure to scientists and polar data. Through professional development and the creation of data tools, Polar ICE will reduce the logistical costs of bringing polar science to students in grades 6-16. We will provide opportunities to: 1) build capacity of polar scientists in communicating and engaging with diverse audiences; 2) create scalable, in-person and virtual opportunities for educators and students to engage with polar scientists and their research through data visualizations, data activities, educator workshops, webinars, and student research symposia; and 3) evaluate the outcomes of Polar ICE and contribute to our understanding of science education practices. We will use a blended learning approach to promote partnerships and cross-disciplinary sharing. This combined multi-pronged approach

  12. Ballerina - pirouettes in search of gamma bursts

    DEFF Research Database (Denmark)

    Brandt, Søren Kristian; Lund, Niels; Pedersen, Henrik

    1999-01-01

    The cosmological origin of gamma ray bursts has now been established with reasonable certainty, Many more bursts will need to be studied to establish the typical distance scale, and to map out the large diversity in properties which have been indicated by the first handful of events. We are propo...... are proposing Ballerina, a small satellite to provide accurate positions and new data on the gamma-ray bursts. We anticipate a detection rate an order of magnitude larger than obtained from Beppo-SAX....

  13. Linear polarization measurements at H. beta. of early-type emission line stars

    Energy Technology Data Exchange (ETDEWEB)

    Clarke, D; McLean, I S [Glasgow Univ. (UK)

    1976-02-01

    Linear polarization measurements across the H..beta.. emission lines of the stars ..gamma.. Cas, zeta Tau and 48 Per are presented. For the first two stars there is a marked reduction of the polarization at the centre of the line and for ..gamma.. Cas, this varies from night to night. During the H..beta.. observations of zeta Tau, a change of polarization over tens of minutes was indicated in a monitor channel tuned to the continuum on the blue side of H..beta... For the fainter star, 48 Per, the uncertainties of the polarimetry were increased in relation to ..gamma.. Cas and zeta Tau by a factor of about two and at this precision, no differential effects across the line were recorded. Observations of ..cap alpha.. Cyg are also given to demonstrate the reliability of the polarimeter.

  14. The gamma function

    CERN Document Server

    Artin, Emil

    2015-01-01

    This brief monograph on the gamma function was designed by the author to fill what he perceived as a gap in the literature of mathematics, which often treated the gamma function in a manner he described as both sketchy and overly complicated. Author Emil Artin, one of the twentieth century's leading mathematicians, wrote in his Preface to this book, ""I feel that this monograph will help to show that the gamma function can be thought of as one of the elementary functions, and that all of its basic properties can be established using elementary methods of the calculus."" Generations of teachers

  15. Polarizing a stored proton beam by spin flip?

    International Nuclear Information System (INIS)

    Oellers, D.; Barion, L.; Barsov, S.; Bechstedt, U.; Benati, P.; Bertelli, S.; Chiladze, D.; Ciullo, G.; Contalbrigo, M.; Dalpiaz, P.F.; Dietrich, J.; Dolfus, N.; Dymov, S.; Engels, R.; Erven, W.; Garishvili, A.; Gebel, R.; Goslawski, P.

    2009-01-01

    We discuss polarizing a proton beam in a storage ring, either by selective removal or by spin flip of the stored ions. Prompted by recent, conflicting calculations, we have carried out a measurement of the spin-flip cross section in low-energy electron-proton scattering. The experiment uses the cooling electron beam at COSY as an electron target. The measured cross sections are too small for making spin flip a viable tool in polarizing a stored beam. This invalidates a recent proposal to use co-moving polarized positrons to polarize a stored antiproton beam.

  16. Polarization-Insensitive Surface Plasmon Polarization Electro-Absorption Modulator Based on Epsilon-Near-Zero Indium Tin Oxide

    Science.gov (United States)

    Jin, Lin; Wen, Long; Liang, Li; Chen, Qin; Sun, Yunfei

    2018-02-01

    CMOS-compatible plasmonic modulators operating at the telecom wavelength are significant for a variety of on-chip applications. Relying on the manipulation of the transverse magnetic (TM) mode excited on the metal-dielectric interface, most of the previous demonstrations are designed to response only for specific polarization state. In this case, it will lead to a high polarization dependent loss, when the polarization-sensitive modulator integrates to a fiber with random polarization state. Herein, we propose a plasmonic modulator utilizing a metal-oxide indium tin oxide (ITO) wrapped around the silicon waveguide and investigate its optical modulation ability for both the vertical and horizontal polarized guiding light by tuning electro-absorption of ITO with the field-induced carrier injection. The electrically biased modulator with electron accumulated at the ITO/oxide interface allows for epsilon-near-zero (ENZ) mode to be excited at the top or lateral portion of the interface depending on the polarization state of the guiding light. Because of the high localized feature of ENZ mode, efficient electro-absorption can be achieved under the "OFF" state of the device, thus leading to large extinction ratio (ER) for both polarizations in our proposed modulator. Further, the polarization-insensitive modulation is realized by properly tailoring the thickness of oxide in two different stacking directions and therefore matching the ER values for device operating at vertical and horizontal polarized modes. For the optimized geometry configuration, the difference between the ER values of two polarization modes, i.e., the ΔER, as small as 0.01 dB/μm is demonstrated and, simultaneously with coupling efficiency above 74%, is obtained for both polarizations at a wavelength of 1.55 μm. The proposed plasmonic-combined modulator has a potential application in guiding and processing of light from a fiber with a random polarization state.

  17. Polarized Light Microscopy

    Science.gov (United States)

    Frandsen, Athela F.

    2016-01-01

    Polarized light microscopy (PLM) is a technique which employs the use of polarizing filters to obtain substantial optical property information about the material which is being observed. This information can be combined with other microscopy techniques to confirm or elucidate the identity of an unknown material, determine whether a particular contaminant is present (as with asbestos analysis), or to provide important information that can be used to refine a manufacturing or chemical process. PLM was the major microscopy technique in use for identification of materials for nearly a century since its introduction in 1834 by William Fox Talbot, as other techniques such as SEM (Scanning Electron Microscopy), FTIR (Fourier Transform Infrared spectroscopy), XPD (X-ray Powder Diffraction), and TEM (Transmission Electron Microscopy) had not yet been developed. Today, it is still the only technique approved by the Environmental Protection Agency (EPA) for asbestos analysis, and is often the technique first applied for identification of unknown materials. PLM uses different configurations in order to determine different material properties. With each configuration additional clues can be gathered, leading to a conclusion of material identity. With no polarizing filter, the microscope can be used just as a stereo optical microscope, and view qualities such as morphology, size, and number of phases. With a single polarizing filter (single polars), additional properties can be established, such as pleochroism, individual refractive indices, and dispersion staining. With two polarizing filters (crossed polars), even more can be deduced: isotropy vs. anisotropy, extinction angle, birefringence/degree of birefringence, sign of elongation, and anomalous polarization colors, among others. With the use of PLM many of these properties can be determined in a matter of seconds, even for those who are not highly trained. McCrone, a leader in the field of polarized light microscopy, often

  18. When measured spin polarization is not spin polarization

    International Nuclear Information System (INIS)

    Dowben, P A; Wu Ning; Binek, Christian

    2011-01-01

    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 CrO 2 and Cr 2 O 3 illustrate some of the complications which hinders comparisons of spin polarization values. (viewpoint)

  19. Polarimetric Analysis of the Long Duration Gamma-Ray Burst GRB 160530A With the Balloon Borne Compton Spectrometer and Imager

    Energy Technology Data Exchange (ETDEWEB)

    Lowell, A. W.; Boggs, S. E; Chiu, C. L.; Kierans, C. A.; Sleator, C.; Tomsick, J. A.; Zoglauer, A. C. [Space Sciences Laboratory, University of California, Berkeley (United States); Chang, H.-K.; Tseng, C.-H.; Yang, C.-Y. [Institute of Astronomy, National Tsing Hua University, Taiwan (China); Jean, P.; Ballmoos, P. von [IRAP Toulouse (France); Lin, C.-H. [Institute of Physics, Academia Sinica, Taiwan (China); Amman, M. [Lawrence Berkeley National Laboratory (United States)

    2017-10-20

    A long duration gamma-ray burst, GRB 160530A, was detected by the Compton Spectrometer and Imager (COSI) during the 2016 COSI Super Pressure Balloon campaign. As a Compton telescope, COSI is inherently sensitive to the polarization of gamma-ray sources in the energy range 0.2–5.0 MeV. We measured the polarization of GRB 160530A using (1) a standard method (SM) based on fitting the distribution of azimuthal scattering angles with a modulation curve and (2) an unbinned, maximum likelihood method (MLM). In both cases, the measured polarization level was below the 99% confidence minimum detectable polarization levels of 72.3% ± 0.8% (SM) and 57.5% ± 0.8% (MLM). Therefore, COSI did not detect polarized gamma-ray emission from this burst. Our most constraining 90% confidence upper limit on the polarization level was 46% (MLM).

  20. Basics of Gamma Ray Detection

    Energy Technology Data Exchange (ETDEWEB)

    Stinnett, Jacob [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Venkataraman, Ram [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-09-13

    The objective of this training is to explain the origin of x-rays and gamma rays, gamma ray interactions with matter, detectors and electronics used in gamma ray-spectrometry, and features of a gamma-ray spectrum for nuclear material that is safeguarded.

  1. 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.

  2. Broadband reflective multi-polarization converter based on single-layer double-L-shaped metasurface

    Science.gov (United States)

    Mao, Chenyang; Yang, Yang; He, Xiaoxiang; Zheng, Jingming; Zhou, Chun

    2017-12-01

    In this paper, a broadband reflective multi-polarization converter based on single-layer double-L-shaped metasurface is proposed. The proposed metasurface can effectively convert linear-polarized (TE/TM) incident wave into the reflected wave with three different polarizations within the frequency bands of 5.5-22.75 GHz. Based on the electric and magnetic resonant features of the double-L-shaped structure, the proposed metasurface can convert linearly polarized waves into cross-polarized waves at three resonant frequency bands. Furthermore, the incident linearly polarized waves can be effectively converted into left/right handed circular-polarized (LHCP and RHCP) waves at other four non-resonance frequency bands. Thus, the proposed metasurface can be regarded as a seven-band multi-polarization converter. The prototype of the proposed polarization converter is analyzed and measured. Both simulated and measured results show the 3-dB axis ratio bandwidth of circular polarization bands and the high polarization conversion efficiency of cross-polarization bands when the incident wave changes from 0° to 30° at both TE and TM modes.

  3. The evolution of tensor polarization

    International Nuclear Information System (INIS)

    Huang, H.; Lee, S.Y.; Ratner, L.

    1993-01-01

    By using the equation of motion for the vector polarization, the spin transfer matrix for spin tensor polarization, the spin transfer matrix for spin tensor polarization is derived. The evolution equation for the tensor polarization is studied in the presence of an isolate spin resonance and in the presence of a spin rotor, or snake

  4. The polarization of fast neutrons

    International Nuclear Information System (INIS)

    Talov, V.V.

    2000-01-01

    The present work is the review of polarization of fast neutrons and methods of polarization analysis. This also includes information about polarization of fast neutrons from first papers, which described polarization in the D(d,n) 3 He, 7 Li(p,n) 7 Be, and T(p,n) 3 He reactions. (authors)

  5. Towards an International Polar Data Coordination Network

    Directory of Open Access Journals (Sweden)

    P L Pulsifer

    2014-10-01

    Full Text Available Data management is integral to sound polar science. Through analysis of documents reporting on meetings of the Arctic data management community, a set of priorities and strategies are identified. These include the need to improve data sharing, make use of existing resources, and better engage stakeholders. Network theory is applied to a preliminary inventory of polar and global data management actors to improve understanding of the emerging community of practice. Under the name the Arctic Data Coordination Network, we propose a model network that can support the community in achieving their goals through improving connectivity between existing actors.

  6. Polarization-independent broadband meta-holograms via polarization-dependent nanoholes.

    Science.gov (United States)

    Zhang, Xiaohu; Li, Xiong; Jin, Jinjin; Pu, Mingbo; Ma, Xiaoliang; Luo, Jun; Guo, Yinghui; Wang, Changtao; Luo, Xiangang

    2018-05-17

    Composed of ultrathin metal or dielectric nanostructures, metasurfaces can manipulate the phase, amplitude and polarization of electromagnetic waves at a subwavelength scale, which is promising for flat optical devices. In general, metasurfaces composed of space-variant anisotropic units are sensitive to the incident polarization due to the inherent polarization dependent geometric phase. Here, we implement polarization-independent broadband metasurface holograms constructed by polarization-dependent anisotropic elliptical nanoholes by elaborate design of complex amplitude holograms. The fabricated meta-hologram exhibits a polarization insensitive feature with an acceptable image quality. We verify the feasibility of the design algorithm for three-dimensional (3D) meta-holograms with simulation and the feasibility for two-dimensional (2D) meta-holograms is experimentally demonstrated at a broadband wavelength range from 405 nm to 632.8 nm. The effective polarization-independent broadband complex wavefront control with anisotropic elliptical nanoholes proposed in this paper greatly promotes the practical applications of the metasurface in technologies associated with wavefront manipulation, such as flat lens, colorful holographic displays and optical storage.

  7. GammaWorkshops Proceedings

    DEFF Research Database (Denmark)

    Strålberg, Elisabeth; Klemola, Seppo; Nielsen, Sven Poul

    to the GammaWorkshops. The topics included efficiency transfer, true coincidence summing corrections, self-attenuation corrections, measurement of natural radionuclides (natural decay series), combined measurement uncertainty calculations, and detection limits. These topics covered both lectures and practical...

  8. FTR europia gamma heating

    International Nuclear Information System (INIS)

    Ward, J.T. Jr.

    1975-01-01

    Calculated and experimental gamma heating rates of europia in the Engineering Mockup Critical Assembly (EMC) were correlated. A calculated to experimental (C/E) ratio of 1.086 was established in validating the theoretical approach and computational technique applied in the calculations. Gamma heat deposition rates in the FTR with Eu 2 O 3 control absorbers were determined from three-dimensional calculations. Maximum gamma heating was found to occur near the tip of a half-inserted row 5 control rod assembly--12.8 watts/gm of europia. Gamma heating profiles were established for a single half-inserted europia absorber assembly. Local heat peaking was found not to alter significantly heating rates computed in the FTR core model, where larger mesh interval sizes precluded examination of spatially-limited heating gradients. These computations provide the basis for thermal-hydraulic analyses to ascertain temperature profiles in the FTR under europia control

  9. Beta and Gamma Gradients

    DEFF Research Database (Denmark)

    Løvborg, Leif; Gaffney, C. F.; Clark, P. A.

    1985-01-01

    Experimental and/or theoretical estimates are presented concerning, (i) attenuation within the sample of beta and gamma radiation from the soil, (ii) the gamma dose within the sample due to its own radioactivity, and (iii) the soil gamma dose in the proximity of boundaries between regions...... of differing radioactivity. It is confirmed that removal of the outer 2 mm of sample is adequate to remove influence from soil beta dose and estimates are made of the error introduced by non-removal. Other evaluations include variation of the soil gamma dose near the ground surface and it appears...... that the present practice of avoiding samples above a depth of 0.3 m may be over-cautious...

  10. Gamma spectrometry today

    International Nuclear Information System (INIS)

    Hemingway, J.

    1990-01-01

    This paper reviews the important advances in gamma spectroscopy made in recent years. Improvements in detectors and other components and the addition of on-line computer control systems is discussed. (UK)

  11. Polarized particles in storage rings

    International Nuclear Information System (INIS)

    Derbenev, Ya.S.; Kondratenko, A.M.; Serednyakov, S.I.; Skrinskij, A.N.; Tumajkin, G.M.; Shatunov, Yu.M.

    1977-01-01

    Experiments with polarized beams on the VEPP-2M and SPEAK storage rings are described. Possible methods of producing polarized particle beams in storage rings as well as method of polarization monitoring are counted. Considered are the processes of radiation polarization of electrons and positrons. It is shown, that to preserve radiation polarization the introduction of regions with a strong sign-variable magnetic field is recommended. Methods of polarization measurement are counted. It is suggested for high energies to use dependence of synchrotron radiation power on transverse polarization of electrons and positrons. Examples of using polarizability of colliding beams in storage rings are presented

  12. Design of broadband single polarized antenna

    Science.gov (United States)

    Shin, Phoo Kho; Aziz, Mohamad Zoinol Abidin Abd.; Ahmad, Badrul Hisham; Ramli, Mohamad Hafize Bin; Fauzi, Noor Azamiah Md; Malek, Mohd Fareq Abd

    2015-05-01

    In practical wireless communication application, bandwidth enhancement becomes one of the major design considerations. At the same time, circular polarized (CP) antenna received much attention for the applications of modern wireless communication system when compared to linear polarized (LP) antenna. This is because CP antenna can reduce the multipath effect. Hence, broadband antenna with operating frequency at 2.4GHz for WLAN application is proposed. The proposed antenna is done by using L-probe amendment with rectangular patch. The rectangular patch and copper ground plane is separated with 10mm air gap. This approach is used to enhance the bandwidth and the gain of the proposed antenna. The bandwidth of the designed antenna is more than 200MHz which meet broadband application. The return loss for the antenna is below -10dB to achieved 90% matching efficiency. The position of L-probe feed is altered in order to obtained different polarizations. The broadband antenna had been designed and simulated by using Computer Simulation Technology (CST) software. In this paper, the comparison for single polarized antenna with the design of non-inverted patch and inverted patch is discussed. The characteristics of the S-parameter, axial ratio, gain, surface current for each designed antenna are analyzed.

  13. Dynamic gamma knife radiosurgery

    International Nuclear Information System (INIS)

    Luan Shuang; Swanson, Nathan; Chen Zhe; Ma Lijun

    2009-01-01

    Gamma knife has been the treatment of choice for various brain tumors and functional disorders. Current gamma knife radiosurgery is planned in a 'ball-packing' approach and delivered in a 'step-and-shoot' manner, i.e. it aims to 'pack' the different sized spherical high-dose volumes (called 'shots') into a tumor volume. We have developed a dynamic scheme for gamma knife radiosurgery based on the concept of 'dose-painting' to take advantage of the new robotic patient positioning system on the latest Gamma Knife C(TM) and Perfexion(TM) units. In our scheme, the spherical high dose volume created by the gamma knife unit will be viewed as a 3D spherical 'paintbrush', and treatment planning reduces to finding the best route of this 'paintbrush' to 'paint' a 3D tumor volume. Under our dose-painting concept, gamma knife radiosurgery becomes dynamic, where the patient moves continuously under the robotic positioning system. We have implemented a fully automatic dynamic gamma knife radiosurgery treatment planning system, where the inverse planning problem is solved as a traveling salesman problem combined with constrained least-square optimizations. We have also carried out experimental studies of dynamic gamma knife radiosurgery and showed the following. (1) Dynamic gamma knife radiosurgery is ideally suited for fully automatic inverse planning, where high quality radiosurgery plans can be obtained in minutes of computation. (2) Dynamic radiosurgery plans are more conformal than step-and-shoot plans and can maintain a steep dose gradient (around 13% per mm) between the target tumor volume and the surrounding critical structures. (3) It is possible to prescribe multiple isodose lines with dynamic gamma knife radiosurgery, so that the treatment can cover the periphery of the target volume while escalating the dose for high tumor burden regions. (4) With dynamic gamma knife radiosurgery, one can obtain a family of plans representing a tradeoff between the delivery time and

  14. Dynamic gamma knife radiosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Luan Shuang; Swanson, Nathan; Chen Zhe [Department of Computer Science, University of New Mexico, Albuquerque, NM 87131 (United States); Ma Lijun [Department of Radiation Oncology, University of California San Francisco, San Francisco, CA 94143 (United States)], E-mail: sluan@cs.unm.edu, E-mail: nate@cs.unm.edu, E-mail: zchen@cs.unm.edu, E-mail: lijunma@radonc.ucsf.edu

    2009-03-21

    Gamma knife has been the treatment of choice for various brain tumors and functional disorders. Current gamma knife radiosurgery is planned in a 'ball-packing' approach and delivered in a 'step-and-shoot' manner, i.e. it aims to 'pack' the different sized spherical high-dose volumes (called 'shots') into a tumor volume. We have developed a dynamic scheme for gamma knife radiosurgery based on the concept of 'dose-painting' to take advantage of the new robotic patient positioning system on the latest Gamma Knife C(TM) and Perfexion(TM) units. In our scheme, the spherical high dose volume created by the gamma knife unit will be viewed as a 3D spherical 'paintbrush', and treatment planning reduces to finding the best route of this 'paintbrush' to 'paint' a 3D tumor volume. Under our dose-painting concept, gamma knife radiosurgery becomes dynamic, where the patient moves continuously under the robotic positioning system. We have implemented a fully automatic dynamic gamma knife radiosurgery treatment planning system, where the inverse planning problem is solved as a traveling salesman problem combined with constrained least-square optimizations. We have also carried out experimental studies of dynamic gamma knife radiosurgery and showed the following. (1) Dynamic gamma knife radiosurgery is ideally suited for fully automatic inverse planning, where high quality radiosurgery plans can be obtained in minutes of computation. (2) Dynamic radiosurgery plans are more conformal than step-and-shoot plans and can maintain a steep dose gradient (around 13% per mm) between the target tumor volume and the surrounding critical structures. (3) It is possible to prescribe multiple isodose lines with dynamic gamma knife radiosurgery, so that the treatment can cover the periphery of the target volume while escalating the dose for high tumor burden regions. (4) With dynamic gamma knife radiosurgery, one can

  15. Polarized electrons at Jefferson laboratory

    International Nuclear Information System (INIS)

    Sinclair, C.K.

    1998-01-01

    The CEBAF accelerator at Jefferson laboratory can deliver CW electron beams to three experimental halls simultaneously. A large fraction of the approved scientific program at the lab requires polarized electron beams. Many of these experiments, both polarized and unpolarized, require high average beam current as well. Since all electrons delivered to the experimental halls originate from the same cathode, delivery of polarized beam to a single hall requires using the polarized source to deliver beam to all experiments in simultaneous operation. The polarized source effort at Jefferson Lab is directed at obtaining very long polarized source operational lifetimes at high average current and beam polarization; at developing the capability to deliver all electrons leaving the polarized source to the experimental halls; and at delivering polarized beam to multiple experimental halls simultaneously. Initial operational experience with the polarized source will be presented. copyright 1998 American Institute of Physics

  16. Polarized Electrons at Jefferson Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Sinclair, C.K.

    1997-12-31

    The CEBAF accelerator at Jefferson laboratory can deliver CW electron beams to three experimental halls simultaneously. A large fraction of the approved scientific program at the lab requires polarized electron beams. Many of these experiments, both polarized and unpolarized, require high average beam current as well. Since all electrons delivered to the experimental halls originate from the same cathode, delivery of polarized beam to a single hall requires using the polarized source to deliver beam to all experiments in simultaneous operation. The polarized source effort at Jefferson Lab is directed at obtaining very long polarized source operational lifetimes at high average current and beam polarization; at developing the capability to deliver all electrons leaving the polarized source to the experimental halls; and at delivering polarized beam to multiple experimental halls simultaneously.initial operational experience with the polarized source will be presented.

  17. Polarized positrons and electrons at the linear collider

    International Nuclear Information System (INIS)

    Moortgat-Pick, G.; Abe, T.; Alexander, G.; Ananthanarayan, B.; Babich, A.A.; Bharadwaj, V.; Barber, D.; Bartl, A.; Brachmann, A.; Chen, S.; Clarke, J.; Clendenin, J.E.; Dainton, J.; Desch, K.; Diehl, M.; Dobos, B.; Dorland, T.; Dreiner, H.K.; Eberl, H.; Ellis, J.

    2008-01-01

    The proposed International Linear Collider (ILC) is well-suited for discovering physics beyond the Standard Model and for precisely unraveling the structure of the underlying physics. The physics return can be maximized by the use of polarized beams. This report shows the paramount role of polarized beams and summarizes the benefits obtained from polarizing the positron beam, as well as the electron beam. The physics case for this option is illustrated explicitly by analyzing reference reactions in different physics scenarios. The results show that positron polarization, combined with the clean experimental environment provided by the linear collider, allows to improve strongly the potential of searches for new particles and the identification of their dynamics, which opens the road to resolve shortcomings of the Standard Model. The report also presents an overview of possible designs for polarizing both beams at the ILC, as well as for measuring their polarization

  18. Very high energy gamma-ray astronomy

    International Nuclear Information System (INIS)

    Weekes, T.C.

    1988-01-01

    Current interest in gamma-ray astronomy at energies above 100 GeV comes from the identification of Cygnus X-3 and other X-ray binaries as sources. In addition there are reports of emission from radio pulsars and a variety of other objects. The statistical significance of many of the observations is not high and many reported effects await confirmation, but there are a sufficient number of independent reports that very high energy gamma-ray astronomy must now be considered to have an observational basis. The observations are summarized with particular emphasis on those reported since 1980. The techniques used - the detection of small air showers using the secondary photons and particles at ground level - are unusual and are described. Future prospects for the field are discussed in relation to new ground-based experiments, satellite gamma-ray studies and proposed neutrino astronomy experiments. (orig.) With 296 refs

  19. A simple and efficient methodology to improve geometric accuracy in gamma knife radiation surgery: implementation in multiple brain metastases.

    Science.gov (United States)

    Karaiskos, Pantelis; Moutsatsos, Argyris; Pappas, Eleftherios; Georgiou, Evangelos; Roussakis, Arkadios; Torrens, Michael; Seimenis, Ioannis

    2014-12-01

    To propose, verify, and implement a simple and efficient methodology for the improvement of total geometric accuracy in multiple brain metastases gamma knife (GK) radiation surgery. The proposed methodology exploits the directional dependence of magnetic resonance imaging (MRI)-related spatial distortions stemming from background field inhomogeneities, also known as sequence-dependent distortions, with respect to the read-gradient polarity during MRI acquisition. First, an extra MRI pulse sequence is acquired with the same imaging parameters as those used for routine patient imaging, aside from a reversal in the read-gradient polarity. Then, "average" image data are compounded from data acquired from the 2 MRI sequences and are used for treatment planning purposes. The method was applied and verified in a polymer gel phantom irradiated with multiple shots in an extended region of the GK stereotactic space. Its clinical impact in dose delivery accuracy was assessed in 15 patients with a total of 96 relatively small (series. Due to these uncertainties, a considerable underdosage (5%-32% of the prescription dose) was found in 33% of the studied targets. The proposed methodology is simple and straightforward in its implementation. Regarding multiple brain metastases applications, the suggested approach may substantially improve total GK dose delivery accuracy in smaller, outlying targets. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. IMEF gamma scanning system

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Sang Yeol; Park, Dae Kyu; Ahn, Sang Bok; Ju, Yong Sun; Jeon, Yong Bum

    1997-06-01

    The gamma scanning system which is installed in IMEF is the equipment obtaining the gamma ray spectrum from irradiated fuels. This equipment could afford the useful data relating spent fuels like as burn-up measurements. We describe the specifications of the equipment and its accessories, and also described its operation procedure so that an operator can use this report as the operation procedure. (author). 1 tab., 11 figs., 11 refs.

  1. IMEF gamma scanning system

    International Nuclear Information System (INIS)

    Baek, Sang Yeol; Park, Dae Kyu; Ahn, Sang Bok; Ju, Yong Sun; Jeon, Yong Bum.

    1997-06-01

    The gamma scanning system which is installed in IMEF is the equipment obtaining the gamma ray spectrum from irradiated fuels. This equipment could afford the useful data relating spent fuels like as burn-up measurements. We describe the specifications of the equipment and its accessories, and also described its operation procedure so that an operator can use this report as the operation procedure. (author). 1 tab., 11 figs., 11 refs

  2. High-energy gamma-ray emission in compact binaries

    International Nuclear Information System (INIS)

    Cerutti, Benoit

    2010-01-01

    Four gamma-ray sources have been associated with binary systems in our Galaxy: the micro-quasar Cygnus X-3 and the gamma-ray binaries LS I +61 degrees 303, LS 5039 and PSR B1259-63. These systems are composed of a massive companion star and a compact object of unknown nature, except in PSR B1259-63 where there is a young pulsar. I propose a comprehensive theoretical model for the high-energy gamma-ray emission and variability in gamma-ray emitting binaries. In this model, the high-energy radiation is produced by inverse Compton scattering of stellar photons on ultra-relativistic electron-positron pairs injected by a young pulsar in gamma-ray binaries and in a relativistic jet in micro-quasars. Considering anisotropic inverse Compton scattering, pair production and pair cascade emission, the TeV gamma-ray emission is well explained in LS 5039. Nevertheless, this model cannot account for the gamma-ray emission in LS I +61 degrees 303 and PSR B1259-63. Other processes should dominate in these complex systems. In Cygnus X-3, the gamma-ray radiation is convincingly reproduced by Doppler-boosted Compton emission of pairs in a relativistic jet. Gamma-ray binaries and micro-quasars provide a novel environment for the study of pulsar winds and relativistic jets at very small spatial scales. (author)

  3. Production of spin-polarized unstable nuclei by using polarized electron capture process

    International Nuclear Information System (INIS)

    Shimizu, S.

    1998-01-01

    Measurements of emitted radiation from spin polarized nuclei are used to get information on electromagnetic moment of ground state unstable nuclei together with spin or parity state of excited states of their decayed (daughter) nuclei. These data are known to be useful for experimental investigation into the structure of unstable nuclei far from the stability line. The present study aims to establish a general method applicable to 11 Be and 16 N nuclei. To produce spin polarization, a new method in which the electron spin polarization of Rb is firstly produced by laser pumping, then the electron is transferred to the unstable nuclear beam (RNB) when they passes through the Rb vapor is proposed. Finally the polarized RNB will be implanted into superfluid helium to remain with a long spin-relaxation time. Future experimental set up for the above measurement adopted in the available radioactive nuclear beam facilities is briefly described. (Ohno, S.)

  4. A novel polarization demodulation method using polarization beam splitter (PBS) for dynamic pressure sensor

    Science.gov (United States)

    Su, Yang; Zhou, Hua; Wang, Yiming; Shen, Huiping

    2018-03-01

    In this paper we propose a new design to demodulate polarization properties induced by pressure using a PBS (polarization beam splitter), which is different with traditional polarimeter based on the 4-detector polarization measurement approach. The theoretical model is established by Muller matrix method. Experimental results confirm the validity of our analysis. Proportional relationships and linear fit are found between output signal and applied pressure. A maximum sensitivity of 0.092182 mv/mv is experimentally achieved and the frequency response exhibits a <0.14 dB variation across the measurement bandwidth. The sensitivity dependence on incident SOP (state of polarization) is investigated. The simple and all-fiber configuration, low-cost and high speed potential make it promising for fiber-based dynamic pressure sensing.

  5. Chiral retrieval method based on right circularly polarized and left circularly polarized waves

    International Nuclear Information System (INIS)

    Martín, Ernesto; Muñoz, Juan; Margineda, José; Molina-Cuberos, Gregorio J; García-Collado, Ángel J

    2014-01-01

    The free-wave characterization of metamaterials is usually carried out by illuminating a sample with a linearly polarized plane electromagnetic wave. At points before and after the sample, sensors are introduced to measure the transverse components of the field, in order to compute the reflection and transmission coefficients related with the co- and cross-polar field components. Based on this information, retrieval algorithms allow parameters like rotation angle, effective chirality and refraction index to be calculated. Here we propose to use the transmission signals under illumination with plane circularly polarized waves, without sensing the reflection signal, to calculate the chirality parameter and the rotation angle due to the electromagnetic activity of the material. This new method, which allows a simpler characterization of a chiral slab, is applied to the study of metamaterials composed of both periodic and random distributions of metallic structures with chiral symmetry. The experimental results are contrasted with simulations and alternative measurements obtained using linearly polarized waves. (paper)

  6. Michel Borghini as a Mentor and Father of the Theory of Polarization in Polarized Targets

    Science.gov (United States)

    de Boer, Wim

    2016-02-01

    This paper is a contribution to the memorial session for Michel Borghini at the Spin 2014 conference in Bejing, honoring his pivotal role for the development of polarized targets in high energy physics. Borghini proposed for the first time the correct mechanism for dynamic polarization in polarized targets using organic materials doped with free radicals. In these amorphous materials the spin levels are broadened by spin-spin interactions and g-factor anisotropy, which allows a high dynamic polarization of nuclei by cooling of the spin-spin interaction reservoir. In this contribution I summarize the experimental evidence for this mechanism. These pertinent experiments were done at CERN in the years 1971 - 1974, when I was a graduate student under the guidance of Michel Borghini. I finish by shortly describing how Borghini’s spin temperature theory is now applied in cancer therapy.

  7. Invited article: polarization "down under": the polarized time-of-flight neutron reflectometer PLATYPUS.

    Science.gov (United States)

    Saerbeck, T; Klose, F; Le Brun, A P; Füzi, J; Brule, A; Nelson, A; Holt, S A; James, M

    2012-08-01

    This review presents the implementation and full characterization of the polarization equipment of the time-of-flight neutron reflectometer PLATYPUS at the Australian Nuclear Science and Technology Organisation (ANSTO). The functionality and efficiency of individual components are evaluated and found to maintain a high neutron beam polarization with a maximum of 99.3% through polarizing Fe/Si supermirrors. Neutron spin-flippers with efficiencies of 99.7% give full control over the incident and scattered neutron spin direction over the whole wavelength spectrum available in the instrument. The first scientific experiments illustrate data correction mechanisms for finite polarizations and reveal an extraordinarily high reproducibility for measuring magnetic thin film samples. The setup is now fully commissioned and available for users through the neutron beam proposal system of the Bragg Institute at ANSTO.

  8. Proceedings of the workshop on polarized targets in storage rings

    International Nuclear Information System (INIS)

    Holt, R.J.

    1984-08-01

    Polarization phenomena have played an increasingly important part in the study of nuclei and nucleons in recent years. Polarization studies have been hampered by the relatively few and rather fragile polarized targets which are presently available. The concept of polarized gas targets in storage rings opens a much wider range of possibilities than is available in the external target geometry. This novel method will represent a considerable advance in nuclear physics and will continue to receive much attention in plans for future facilities. An internal, polarized-target station is being planned for the cooler ring at the Indiana University Cyclotron Facility. Internal targets are compatible with recent designs of electron accelerators proposed by the Massachusetts Institute of Technology and the Southeastern Universities Research Association. The key to nuclear-science programs based on internal targets pivots on recent developments in polarized atomic beam methods, which include the more recent laser-driven polarized targets. The workshop drew together a unique group of physicists in the fields of high-energy, nuclear and atomic physics. The meeting was organized in a manner that stimulated discussion among the 58 participants and focused on developments in polarized target technology and the underlying atomic physics. An impressive array of future possibilities for polarized targets as well as current developments in polarized target technology were discussed at the workshop. Abstracts of individual items from the workshop were prepared separately for the data base

  9. Polarized protons at RHIC

    International Nuclear Information System (INIS)

    Tannenbaum, M.J.

    1990-12-01

    The Physics case is presented for the use of polarized protons at RHIC for one or two months each year. This would provide a facility with polarizations of approx-gt 50% high luminosity ∼2.0 x 10 32 cm -2 s -1 , the possibility of both longitudinal and transverse polarization at the interaction regions, and frequent polarization reversal for control of systematic errors. The annual integrated luminosity for such running (∼10 6 sec per year) would be ∫ Ldt = 2 x 10 38 cm -2 -- roughly 20 times the total luminosity integrated in ∼ 10 years of operation of the CERN Collider (∼10 inverse picobarns, 10 37 cm -2 ). This facility would be unique in the ability to perform parity-violating measurements and polarization test of QCD. Also, the existence of p-p collisions in a new energy range would permit the study of ''classical'' reactions like the total cross section and elastic scattering, etc., and serve as a complement to measurements from p-bar p colliders. 11 refs

  10. The Bochum Polarized Target

    International Nuclear Information System (INIS)

    Reicherz, G.; Goertz, S.; Harmsen, J.; Heckmann, J.; Meier, A.; Meyer, W.; Radtke, E.

    2001-01-01

    The Bochum 'Polarized Target' group develops the target material 6 LiD for the COMPASS experiment at CERN. Several different materials like alcohols, alcanes and ammonia are under investigation. Solid State Targets are polarized in magnetic fields higher than B=2.5T and at temperatures below T=1K. For the Dynamic Nuclear Polarization process, paramagnetic centers are induced chemically or by irradiation with ionizing beams. The radical density is a critical factor for optimization of polarization and relaxation times at adequate magnetic fields and temperatures. In a high sensitive EPR--apparatus, an evaporator and a dilution cryostat with a continuous wave NMR--system, the materials are investigated and optimized. To improve the polarization measurement, the Liverpool NMR-box is modified by exchanging the fixed capacitor for a varicap diode which not only makes the tuning very easy but also provides a continuously tuned circuit. The dependence of the signal area upon the circuit current is measured and it is shown that it follows a linear function

  11. A Bionic Polarization Navigation Sensor and Its Calibration Method.

    Science.gov (United States)

    Zhao, Huijie; Xu, Wujian

    2016-08-03

    The polarization patterns of skylight which arise due to the scattering of sunlight in the atmosphere can be used by many insects for deriving compass information. Inspired by insects' polarized light compass, scientists have developed a new kind of navigation method. One of the key techniques in this method is the polarimetric sensor which is used to acquire direction information from skylight. In this paper, a polarization navigation sensor is proposed which imitates the working principles of the polarization vision systems of insects. We introduce the optical design and mathematical model of the sensor. In addition, a calibration method based on variable substitution and non-linear curve fitting is proposed. The results obtained from the outdoor experiments provide support for the feasibility and precision of the sensor. The sensor's signal processing can be well described using our mathematical model. A relatively high degree of accuracy in polarization measurement can be obtained without any error compensation.

  12. Toward standardising gamma camera quality control procedures

    International Nuclear Information System (INIS)

    Alkhorayef, M.A.; Alnaaimi, M.A.; Alduaij, M.A.; Mohamed, M.O.; Ibahim, S.Y.; Alkandari, F.A.; Bradley, D.A.

    2015-01-01

    Attaining high standards of efficiency and reliability in the practice of nuclear medicine requires appropriate quality control (QC) programs. For instance, the regular evaluation and comparison of extrinsic and intrinsic flood-field uniformity enables the quick correction of many gamma camera problems. Whereas QC tests for uniformity are usually performed by exposing the gamma camera crystal to a uniform flux of gamma radiation from a source of known activity, such protocols can vary significantly. Thus, there is a need for optimization and standardization, in part to allow direct comparison between gamma cameras from different vendors. In the present study, intrinsic uniformity was examined as a function of source distance, source activity, source volume and number of counts. The extrinsic uniformity and spatial resolution were also examined. Proper standard QC procedures need to be implemented because of the continual development of nuclear medicine imaging technology and the rapid expansion and increasing complexity of hybrid imaging system data. The present work seeks to promote a set of standard testing procedures to contribute to the delivery of safe and effective nuclear medicine services. - Highlights: • Optimal parameters for quality control of the gamma camera are proposed. • For extrinsic and intrinsic uniformity a minimum of 15,000 counts is recommended. • For intrinsic flood uniformity the activity should not exceed 100 µCi (3.7 MBq). • For intrinsic uniformity the source to detector distance should be at least 60 cm. • The bar phantom measurement must be performed with at least 15 million counts.

  13. Laue optics for nuclear astrophysics: New detector requirements for focused gamma-ray beams

    Energy Technology Data Exchange (ETDEWEB)

    Barriere, N. [INAF - IASF Roma, via Fosso del Cavaliere 100, 00133 Roma (Italy)], E-mail: nicolas.barriere@iasf-roma.inaf.it; Ballmoos, P. von [CESR - UMR 5187, 9 Av. du Colonel Roche, 31028 Toulouse (France); Abrosimov, N.V. [IKZ, Max Born-Str. 2, D-12489 Berlin (Germany); Bastie, P. [LSP UMR 5588, 140 Av. de la physique, 38402 Saint Martin d' Heres (France); Camus, T. [CESR - UMR 5187, 9 Av. du Colonel Roche, 31028 Toulouse (France); Courtois, P.; Jentschel, M. [ILL, 6 rue Jules Horowitz, 38042 Grenoble (France); Knoedlseder, J. [CESR - UMR 5187, 9 Av. du Colonel Roche, 31028 Toulouse (France); Natalucci, L. [INAF - IASF Roma, via Fosso del Cavaliere 100, 00133 Roma (Italy); Roudil, G.; Rousselle, J. [CESR - UMR 5187, 9 Av. du Colonel Roche, 31028 Toulouse (France); Wunderer, C.B. [SSL, University of California at Berkeley, CA 94708 (United States); Kurlov, V.N. [Institute of Solid State Physics of Russian Academy of Sciences, 142432 Chernogolovka (Russian Federation)

    2009-10-21

    Nuclear astrophysics presents an extraordinary scientific potential for the study of the most powerful sources and the most violent events in the Universe. But in order to take full advantage of this potential, telescopes should be at least an order of magnitude more sensitive than present technologies. Today, Laue lenses have demonstrated their capability of focusing gamma-rays in the 100 keV-1 MeV domain, enabling the possibility of building a new generation of instruments for which sensitive area is decoupled from collecting area. Thus we have now the opportunity of dramatically increase the signal/background ratio and hence improve significantly the sensitivity. With a lens, the best detector is no longer the largest possible within a mission envelope. The point spread function of a Laue lens measures a few centimeters in diameter, but the field of view is limited by the detector size. Requirements for a focal plane instrument are presented in the context of the Gamma-Ray Imager mission (proposed to European Space Agency, ESA in the framework of the first Cosmic Vision AO): a 15-20 cm a side finely pixellated detector capable of Compton events reconstruction seems to be optimal, giving polarization and background rejection capabilities and 30 arcsec of angular resolution within a field of view of 5 arc min.

  14. Polarized source upgrading

    International Nuclear Information System (INIS)

    Clegg, T.B.; Rummel, R.L.; Carter, E.P.; Westerfeldt, C.R.; Lovette, A.W.; Edwards, S.E.

    1985-01-01

    The decision was made this past year to move the Lamb-shift polarized ion source which was first installed in the laboratory in 1970. The motivation was the need to improve the flexibility of spin-axis orientation by installing the ion source with a new Wien-filter spin precessor which is capable of rotating physically about the beam axis. The move of the polarized source was accomplished in approximately two months, with the accelerator being turned off for experiments during approximately four weeks of this time. The occasion of the move provided the opportunity to rewire completely the entire polarized ion source frame and to rebuild approximately half of the electronic chassis on the source. The result is an ion source which is now logically wired and carefully documented. Beams obtained from the source are much more stable than those previously available

  15. Spin polarized deuterium

    International Nuclear Information System (INIS)

    Glyde, H.R.; Hernadi, S.I.

    1986-01-01

    Several ground state properties of (electron) spin-polarized deuterium (D) such as the energy, single quasiparticle energies and lifetimes, Landau parameters and sound velocities are evaluated. The calculations begin with the Kolos-Wolneiwicz potential and use the Galitskii-FeynmanHartree-Fock (GFHF) approximation. The deuteron nucleas has spin I = 1, and spin states I/sub z/ = 1,0,-1. We explore D 1 , D 2 and D 3 in which, respectively, one spin state only is populated, two states are equally populated, and three states are equally populated. We find the GFHF describes D 1 well, but D 2 and D 3 less well. The Landau parameters, F/sub L/, are small compared to liquid 3 He and very small for doubly polarized D 1 (i.e. the F/sub L/ decrease with nuclear polarization)

  16. Polarized electron sources

    International Nuclear Information System (INIS)

    Clendenin, J.E.

    1995-05-01

    Polarized electron sources for high energy accelerators took a significant step forward with the introduction of a new laser-driven photocathode source for the SLC in 1992. With an electron beam polarization of >80% and with ∼99% uptime during continuous operation, this source is a key factor in the success of the current SLC high-energy physics program. The SLC source performance is used to illustrate both the capabilities and the limitations of solid-state sources. The beam requirements for future colliders are similar to that of the SLC with the addition in most cases of multiple-bunch operation. A design for the next generation accelerator source that can improve the operational characteristics and at least minimize some of the inherent limitations of present sources is presented. Finally, the possibilities for producing highly polarized electron beams for high-duty-factor accelerators are discussed

  17. Time Domain Induced Polarization

    DEFF Research Database (Denmark)

    Fiandaca, Gianluca; Auken, Esben; Christiansen, Anders Vest

    2012-01-01

    Time-domain-induced polarization has significantly broadened its field of reference during the last decade, from mineral exploration to environmental geophysics, e.g., for clay and peat identification and landfill characterization. Though, insufficient modeling tools have hitherto limited the use...... of time-domaininduced polarization for wider purposes. For these reasons, a new forward code and inversion algorithm have been developed using the full-time decay of the induced polarization response, together with an accurate description of the transmitter waveform and of the receiver transfer function......, to reconstruct the distribution of the Cole-Cole parameters of the earth. The accurate modeling of the transmitter waveform had a strong influence on the forward response, and we showed that the difference between a solution using a step response and a solution using the accurate modeling often is above 100...

  18. A lunar polar expedition

    Science.gov (United States)

    Dowling, Richard; Staehle, Robert L.; Svitek, Tomas

    1992-09-01

    Advanced exploration and development in harsh environments require mastery of basic human survival skill. Expeditions into the lethal climates of Earth's polar regions offer useful lessons for tommorrow's lunar pioneers. In Arctic and Antarctic exploration, 'wintering over' was a crucial milestone. The ability to establish a supply base and survive months of polar cold and darkness made extensive travel and exploration possible. Because of the possibility of near-constant solar illumination, the lunar polar regions, unlike Earth's may offer the most hospitable site for habitation. The World Space Foundation is examining a scenario for establishing a five-person expeditionary team on the lunar north pole for one year. This paper is a status report on a point design addressing site selection, transportation, power, and life support requirements.

  19. Polarized proton and deuteron solid HD targets

    International Nuclear Information System (INIS)

    Honig, A.

    1977-01-01

    A decade has now elapsed since HD was proposed as a polarized proton and deuteron target with exceptionally desirable properties. These include a very high free proton proportion, independently polarizable proton and deuteron systems, and a ''frozen-spin'' mode of operation which allows separation of the functions of production and utilization of the highly polarized target. A discussion is given of what can be expected of the polarized HD system right now, without further research. The basic features of solid HD pertinent to its use as a ''frozen-spin'' target are outlined, then a summary is given of the particular experimental results which support the contention that the target will perform successfully, and finally, some feasible operating modes and the expected performances from them are presented

  20. Quantum switching of polarization in mesoscopic ferroelectrics

    International Nuclear Information System (INIS)

    Sa de Melo, C.A.

    1996-01-01

    A single domain of a uniaxial ferroelectric grain may be thought of as a classical permanent memory. At the mesoscopic level this system may experience considerable quantum fluctuations due to tunneling between two possible memory states, thus destroying the classical permanent memory effect. To study these quantum effects the concrete example of a mesoscopic uniaxial ferroelectric grain is discussed, where the orientation of the electric polarization determines two possible memory states. The possibility of quantum switching of the polarization in mesoscopic uniaxial ferroelectric grains is thus proposed. To determine the degree of memory loss, the tunneling rate between the two polarization states is calculated at zero temperature both in the absence and in the presence of an external static electric field. In addition, a discussion of crossover temperature between thermally activated behavior and quantum tunneling behavior is presented. And finally, environmental effects (phonons, defects, and surfaces) are also considered. copyright 1996 The American Physical Society

  1. Upgrading the AGS polarized beam facility

    International Nuclear Information System (INIS)

    Ratner, L.G.

    1991-01-01

    Although present techniques for crossing depolarizing resonances in circular accelerators work, they are very time-consuming to implement and were only able to provide about a 40% polarized beam at 22 GeV in the Alternating Gradient Synchrotron (AGS). We propose to install a partial ''Siberian Snake'' solenoid in the AGS to eliminate the need to correct imperfection resonances and to make other modifications in our intrinsic resonance correctors. This will allow us to reach an energy of 25 GeV with 70% polarization and will enable the AGS to be an efficient injector of polarized protons into the Relativistic Heavy Ion Collider (RHIC), as well as being able to carry on a fixed-target program with minimum set-up time. 3 refs., 5 figs., 1 tab

  2. Polarizing matter and antimatter: A new method

    International Nuclear Information System (INIS)

    Onel, Y.

    1992-02-01

    Several years ago a self-polarization effect for stored (anti)- protons and ions was investigated theoretically. The effect is based on the well-known Stern-Gerlach effect in gradient fields. The aim of the ongoing measurements at the Indiana University Cyclotron Facility (IUCF) is to verify experimentally the various assumptions on which this effect is based. The final goal is to demonstrate this new polarization effect. The proposed effect could be a powerful tool to produce polarized stored hadron beams both in the low-energy range and at SSC and LHC energies. In this progress report we will describe our progress in three parts: (A) Experimental work at IUCF Cooler Ring; (B) Our extensive computer simulations of the spin stability for the IUCF Cooler Ring; and (C) Theoretical studies

  3. A MATHEMATICAL APPROACH TO ECONOMY OF EXPERIMENT IN DETERMINATIONS OF THE DIFFERENTIAL DOSE ALBEDO OF GAMMA RAYS

    Energy Technology Data Exchange (ETDEWEB)

    Shoemaker, N. F.; Huddleston, C. M.

    1962-12-10

    Treatments of the differential dose albedo of gamma rays on concrete have supposed that the albedo value is a function of: the energy of the incident gamma radiation, the polar angle of incidence, the polar angle of reflection (or scatter), and the azimuthal angle of reflection. It is demonstrated that, if certain reasonable assumptions are made regarding the mechanism of reflection, it is not necessary to investigate variations in albedo with azimuthal angle of refiection. Once differential dose albedo has been determined for a complete set of incident and reflected polar angles with zero azimuth, albedo at any azimuth can be derived by a suitable transformation. (auth)

  4. Thesis Proposal

    DEFF Research Database (Denmark)

    Sloth, Erik

    2010-01-01

    Strukturen i Thesis proposal er følgende: Først præsenteres mine konkrete empiriske forskningsprojekter som skal munde ud i afhandlingens artikler. Jeg præsenterer herefter de teoretiske overvejelser omkring oplevelsesbegrebet og forbrugerkulturteori som danner baggrund for at jeg er nået frem til...

  5. Modelling Polar Self Assembly

    Science.gov (United States)

    Olvera de La Cruz, Monica; Sayar, Mehmet; Solis, Francisco J.; Stupp, Samuel I.

    2001-03-01

    Recent experimental studies in our group have shown that self assembled thin films of noncentrosymmetric supramolecular objects composed of triblock rodcoil molecules exhibit finite polar order. These aggregates have both long range dipolar and short range Ising-like interactions. We study the ground state of a simple model with these competing interactions. We find that the competition between Ising-like and dipolar forces yield a periodic domain structure, which can be controlled by adjusting the force constants and film thickness. When the surface forces are included in the potential, the system exhibits a finite macroscopic polar order.

  6. AGS polarized H- source

    International Nuclear Information System (INIS)

    Kponou, A.; Alessi, J.G.; Sluyters, T.

    1985-01-01

    The AGS polarized H - source is now operational. During a month-long experimental physics run in July 1984, pulses equivalent to 15 μA x 300 μs (approx. 3 x 10 10 protons) were injected into the RFQ preaccelerator. Beam polarization, measured at 200 MeV, was approx. 75%. After the run, a program to increase the H - yield of the source was begun and significant progress has been made. The H - current is now frequently 20 to 30 μA. A description of the source and some details of our operating experience are given. We also briefly describe the improvement program

  7. The polar mesosphere

    International Nuclear Information System (INIS)

    Morris, Ray; Murphy, Damian

    2008-01-01

    The mesosphere region, which lies at the edge of space, contains the coldest layer of the Earth's atmosphere, with summer temperatures as low as minus 130 °C. In this extreme environment ice aerosol layers have appeared since the dawn of industrialization—whose existence may arguably be linked to human influence—on yet another layer of the Earth's fragile atmosphere. Ground-based and space-based experiments conducted in the Arctic and Antarctic during the International Polar Year (IPY) aim to address limitations in our knowledge and to advance our understanding of thermal and dynamical processes at play in the polar mesosphere

  8. Imaging with Polarized Neutrons

    Directory of Open Access Journals (Sweden)

    Nikolay Kardjilov

    2018-01-01

    Full Text Available Owing to their zero charge, neutrons are able to pass through thick layers of matter (typically several centimeters while being sensitive to magnetic fields due to their intrinsic magnetic moment. Therefore, in addition to the conventional attenuation contrast image, the magnetic field inside and around a sample can be visualized by detecting changes of polarization in a transmitted beam. The method is based on the spatially resolved measurement of the cumulative precession angles of a collimated, polarized, monochromatic neutron beam that traverses a magnetic field or sample.

  9. Polarization splitter and polarization rotator designs based on transformation optics.

    Science.gov (United States)

    Kwon, Do-Hoon; Werner, Douglas H

    2008-11-10

    The transformation optics technique is employed in this paper to design two optical devices - a two-dimensional polarization splitter and a three-dimensional polarization rotator for propagating beams. The polarization splitter translates the TM- and the TE-polarized components of an incident beam in opposite directions (i.e., shifted up or shifted down). The polarization rotator rotates the polarization state of an incoming beam by an arbitrary angle. Both optical devices are reflectionless at the entry and exit interfaces. Design details and full-wave simulation results are provided.

  10. 77 FR 23432 - Endangered and Threatened Wildlife and Plants; Special Rule for the Polar Bear

    Science.gov (United States)

    2012-04-19

    ... Polar Bear AGENCY: Fish and Wildlife Service, Interior. ACTION: Proposed rule; availability of draft... and advisable to provide for the conservation of the polar bear (Ursus maritimus). The Secretary has the discretion to prohibit by regulation with respect to the polar bear any act prohibited by section...

  11. GammaSem Proceedings - A Nordic seminar for users of gamma spectrometry

    International Nuclear Information System (INIS)

    Nunez, P.; Klemola, S.; Nielsen, Sven P.; Palsson, S.E.; Israelson, C.

    2010-03-01

    The project GammaSem was proposed to provide a forum for discussions and sharing of information on practical issues concerning gamma spectrometry and to establish a network of users of gamma spectrometry in the Nordic countries, thereby strengthening the collaboration and improving all participants' competence in practical gamma spectrometry. The seminars' focus was practical challenges met by the users themselves, rather than theoretical matters. Scientists and users of gamma spectrometry from all five Nordic countries were invited to the seminar, as well as scientist from the Baltic countries. A total of 75 people participated; representing 34 different universities, commercial companies, research institutes and also all Nordic authorities. During the seminar several key issues for follow-up were identified and working groups for addressing the identified problems were established. The working groups were: 1) Uncertainties and detections of limits 2) True summing coincidence 3) Monte Carlo simulations and efficiency transfer 4) Absorption (density corrections and geometries) 5) Mobile gamma spectrometry systems 6) Nuclear forensics (on special samples and special parts of the spectra). The identified topics will form the basis for the agenda of the next seminar in 2010. There, the different working groups will be invited to present their ideas/solutions to the relevant problems. (author)

  12. GammaSem Proceedings - A Nordic seminar for users of gamma spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Nunez, P. (ed.) (Institute for Energy Technology (IFE) (Norway)); Klemola, S. (Radiation and Nuclear Safety Authority (STUK) (Finland)); Nielsen, Sven P. (Technical Univ. of Denmark, Risoe National Lab. for Sustainable Energy. Roskilde (Denmark)); Palsson, S.E. (Icelandic Radiation Safety Authority (IS)); Israelson, C. (National Institute of Radiation Protection (Denmark))

    2010-03-15

    The project GammaSem was proposed to provide a forum for discussions and sharing of information on practical issues concerning gamma spectrometry and to establish a network of users of gamma spectrometry in the Nordic countries, thereby strengthening the collaboration and improving all participants' competence in practical gamma spectrometry. The seminars' focus was practical challenges met by the users themselves, rather than theoretical matters. Scientists and users of gamma spectrometry from all five Nordic countries were invited to the seminar, as well as scientist from the Baltic countries. A total of 75 people participated; representing 34 different universities, commercial companies, research institutes and also all Nordic authorities. During the seminar several key issues for follow-up were identified and working groups for addressing the identified problems were established. The working groups were: 1) Uncertainties and detections of limits 2) True summing coincidence 3) Monte Carlo simulations and efficiency transfer 4) Absorption (density corrections and geometries) 5) Mobile gamma spectrometry systems 6) Nuclear forensics (on special samples and special parts of the spectra). The identified topics will form the basis for the agenda of the next seminar in 2010. There, the different working groups will be invited to present their ideas/solutions to the relevant problems. (author)

  13. Polarized lepton-nucleon scattering

    International Nuclear Information System (INIS)

    Hughes, E.

    1994-01-01

    The author provides a summary of the proposed and published statistical (systematic) uncertainties from the world experiments on nucleon spin structure function integrals. By the time these programs are complete, there will be a vast resource of data on nucleon spin structure functions. Each program has quite different experimental approaches regarding the beams, targets, and spectrometers thus ensuring systematically independent tests of the spin structure function measurements. Since the field of spin structure function measurements began, there has been a result appearing approximately every five years. With advances in polarized target technology and high polarization in virtually all of the lepton beams, results are now coming out each year; this is a true signature of the growth in the field. Hopefully, the experiments will provide a consistent picture of nucleon spin structure at their completion. In summary, there are still many open questions regarding the internal spin structure of the nucleon. Tests of QCD via the investigation of the Bjorken sum rule is a prime motivator for the field, and will continue with the next round of precision experiments. The question of the origin of spin is still a fundamental problem. Researchers hope is that high-energy probes using spin will shed light on this intriguing mystery, in addition to characterizing the spin structure of the nucleon

  14. Polarized lepton-nucleon scattering

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, E. [Stanford Univ., CA (United States)

    1994-12-01

    The author provides a summary of the proposed and published statistical (systematic) uncertainties from the world experiments on nucleon spin structure function integrals. By the time these programs are complete, there will be a vast resource of data on nucleon spin structure functions. Each program has quite different experimental approaches regarding the beams, targets, and spectrometers thus ensuring systematically independent tests of the spin structure function measurements. Since the field of spin structure function measurements began, there has been a result appearing approximately every five years. With advances in polarized target technology and high polarization in virtually all of the lepton beams, results are now coming out each year; this is a true signature of the growth in the field. Hopefully, the experiments will provide a consistent picture of nucleon spin structure at their completion. In summary, there are still many open questions regarding the internal spin structure of the nucleon. Tests of QCD via the investigation of the Bjorken sum rule is a prime motivator for the field, and will continue with the next round of precision experiments. The question of the origin of spin is still a fundamental problem. Researchers hope is that high-energy probes using spin will shed light on this intriguing mystery, in addition to characterizing the spin structure of the nucleon.

  15. Instrument performance and simulation verification of the POLAR detector

    Science.gov (United States)

    Kole, M.; Li, Z. H.; Produit, N.; Tymieniecka, T.; Zhang, J.; Zwolinska, A.; Bao, T. W.; Bernasconi, T.; Cadoux, F.; Feng, M. Z.; Gauvin, N.; Hajdas, W.; Kong, S. W.; Li, H. C.; Li, L.; Liu, X.; Marcinkowski, R.; Orsi, S.; Pohl, M.; Rybka, D.; Sun, J. C.; Song, L. M.; Szabelski, J.; Wang, R. J.; Wang, Y. H.; Wen, X.; Wu, B. B.; Wu, X.; Xiao, H. L.; Xiong, S. L.; Zhang, L.; Zhang, L. Y.; Zhang, S. N.; Zhang, X. F.; Zhang, Y. J.; Zhao, Y.

    2017-11-01

    POLAR is a new satellite-born detector aiming to measure the polarization of an unprecedented number of Gamma-Ray Bursts in the 50-500 keV energy range. The instrument, launched on-board the Tiangong-2 Chinese Space lab on the 15th of September 2016, is designed to measure the polarization of the hard X-ray flux by measuring the distribution of the azimuthal scattering angles of the incoming photons. A detailed understanding of the polarimeter and specifically of the systematic effects induced by the instrument's non-uniformity are required for this purpose. In order to study the instrument's response to polarization, POLAR underwent a beam test at the European Synchrotron Radiation Facility in France. In this paper both the beam test and the instrument performance will be described. This is followed by an overview of the Monte Carlo simulation tools developed for the instrument. Finally a comparison of the measured and simulated instrument performance will be provided and the instrument response to polarization will be presented.

  16. COST meeting - Polarization and AGN II - Abstracts and slides

    International Nuclear Information System (INIS)

    Kishimoto, M.; Rouan, D.; Tadhunter, C.; Lopez Rodriguez, E.; Braibant, L.; Pasetto, A.; Matt, G.; Afanasiev, V.; Lira, P.; Hutsemekers, D.; Sluse, D.; Marin, F.; Tamborra, F.; Yankova, K.; Laing, R.; Lico, R.; Agudo, I.; Hovatta, T.; Jermak, H.; Chen, X.; Myserlis, I.; Cellone, S.A.; Chidiac, C.; Chakraborty, N.; Bozhilov, V.

    2016-01-01

    This meeting is the 2. COST workshop on Polarization and Active Galactic Nuclei (AGN). Accreting supermassive black holes in active galactic nuclei are the most powerful, long-lasting sources in the universe. Emitting over ten orders of magnitude in photon energy or more, the radiation of AGN encodes information about a multitude of astrophysical processes: accretion, thermal and non-thermal radiative transfer, acceleration of outflows and jets, shock physics, special and general relativity. Observationally, AGN appear as numerous types and polarization studies have played a key role in establishing the idea of a unifying AGN geometry. The topics covered at the meeting include the following: 1) Polarimetry of AGN from the radio to gamma-rays; 2) Tools for modeling and data analysis of AGN polarization; 3) Polarization due to magnetic fields and dust in AGN; 4) Polarization of AGN inflows, outflows and jets; 5) Spectropolarimetry and polarization variability of AGN; and 6) From Sgr A* to the most luminous quasars: what can polarimetry do for AGN (super-)unification? This document is made up of the abstracts and slides of the presentations

  17. POLAR: A Space-borne X-Ray Polarimeter for Transient Sources

    Science.gov (United States)

    Orsi, S.; Polar Collaboration

    2011-02-01

    POLAR is a novel compact Compton X-ray polarimeter designed to measure the linear polarization of the prompt emission of Gamma Ray Bursts (GRB) and other strong transient sources such as soft gamma repeaters and solar flares in the energy range 50-500 keV. A detailed measurement of the polarization from astrophysical sources will lead to a better understanding of the source geometry and emission mechanisms. POLAR is expected to observe every year several GRBs with a minimum detectable polarization smaller than 10%, thanks to its large modulation factor, effective area, and field of view. POLAR consists of 1600 low-Z plastic scintillator bars, divided in 25 independent modular units, each read out by one flat-panel multi-anode photomultiplier. The design of POLAR is reviewed, and results of tests of one modular unit of the engineering and qualification model (EQM) of POLAR with synchrotron radiation are presented. After construction and testing of the full EQM, we will start building the flight model in 2011, in view of the launch foreseen in 2013.

  18. Polarized Proton Collisions at RHIC

    CERN Document Server

    Bai, Mei; Alekseev, Igor G; Alessi, James; Beebe-Wang, Joanne; Blaskiewicz, Michael; Bravar, Alessandro; Brennan, Joseph M; Bruno, Donald; Bunce, Gerry; Butler, John J; Cameron, Peter; Connolly, Roger; De Long, Joseph; Drees, Angelika; Fischer, Wolfram; Ganetis, George; Gardner, Chris J; Glenn, Joseph; Hayes, Thomas; Hseuh Hsiao Chaun; Huang, Haixin; Ingrassia, Peter; Iriso, Ubaldo; Laster, Jonathan S; Lee, Roger C; Luccio, Alfredo U; Luo, Yun; MacKay, William W; Makdisi, Yousef; Marr, Gregory J; Marusic, Al; McIntyre, Gary; Michnoff, Robert; Montag, Christoph; Morris, John; Nicoletti, Tony; Oddo, Peter; Oerter, Brian; Osamu, Jinnouchi; Pilat, Fulvia Caterina; Ptitsyn, Vadim; Roser, Thomas; Satogata, Todd; Smith, Kevin T; Svirida, Dima; Tepikian, Steven; Tomas, Rogelio; Trbojevic, Dejan; Tsoupas, Nicholaos; Tuozzolo, Joseph; Vetter, Kurt; Wilinski, Michelle; Zaltsman, Alex; Zelenski, Anatoli; Zeno, Keith; Zhang, S Y

    2005-01-01

    The Relativistic Heavy Ion Collider~(RHIC) provides not only collisions of ions but also collisions of polarized protons. In a circular accelerator, the polarization of polarized proton beam can be partially or fully lost when a spin depolarizing resonance is encountered. To preserve the beam polarization during acceleration, two full Siberian snakes were employed in RHIC to avoid depolarizing resonances. In 2003, polarized proton beams were accelerated to 100~GeV and collided in RHIC. Beams were brought into collisions with longitudinal polarization at the experiments STAR and PHENIX by using spin rotators. RHIC polarized proton run experience demonstrates that optimizing polarization transmission efficiency and improving luminosity performance are significant challenges. Currently, the luminosity lifetime in RHIC is limited by the beam-beam effect. The current state of RHIC polarized proton program, including its dedicated physics run in 2005 and efforts to optimize luminosity production in beam-beam limite...

  19. Fragmentation functions of polarized heavy quarkonium

    International Nuclear Information System (INIS)

    Ma, Yan-Qing; Qiu, Jian-Wei; Zhang, Hong

    2015-01-01

    Investigating the production of polarized heavy quarkonia in terms of recently proposed QCD factorization formalism requires the knowledge of a large number of input fragmentation functions (FFs) from a single parton or a heavy quark-antiquark pair to a polarized heavy quarkonium. We study these universal FFs at the input factorization scale μ 0 ≳2m Q , with heavy quark mass m Q , in the framework of nonrelativistic QCD (NRQCD) factorization. We express these FFs in terms of perturbatively calculable coefficients for producing a heavy quark-antiquark pair in all possible NRQCD states, multiplied by corresponding NRQCD long-distance matrix elements for the pair to transmute into a polarized heavy quarkonium. We derive all relevant NRQCD operators for the long-distance matrix elements based on symmetries, and introduce a self-consistent scheme to define them in arbitrary d-dimensions. We compute, up to the first non-trivial order in α s , the perturbative coefficients for producing a heavy quark pair in all possible S-wave and P-wave NRQCD states. We also discuss the role of the polarized FFs in generating QCD predictions for the polarization of J/ψ produced at collider energies.

  20. Undulator-Based Production of Polarized Photons

    International Nuclear Information System (INIS)

    McDonald, Kirk

    2008-01-01

    'Project Title: Undulator-Based Production of Polarized Photons' DOE Contract Number: FG02-04ER41355 Principal Investigator: Prof. Kirk McDonald Period of Performance: 09/10/2004 thru 08/31/2006 This award was to fund Princeton's activity on SLAC experiment E166, 'Undulator-Based Production of Polarized Positrons' which was performed at SLAC during June and September 2005. Princeton U. fabricated a magnetic spectrometer for this experiment, and participated in the commissioning, operation, and analysis of the experiment, for which Prof. McDonald was a co-spokesperson. The experiment demonstrated that an intense positron beam with 80% longitudinal polarization could be generated by conversion of MeVenergy circularly polarized photons in a thin target, which photons were generated by passage of high-energy electrons through a helical undulator. This technique has since been adopted as the baseline for the polarized positron source of the proposed International Linear Collider. Results of the experiment have been published in Physical Review Letters, vol 100, p 210801 (2008) (see attached .pdf file), and a longer paper is in preparation.

  1. On the theory of polar ozone holes

    International Nuclear Information System (INIS)

    Njau, E.C.

    1990-12-01

    The viable theories already proposed to explain polar ozone holes generally fall into two main categories, namely, chemical theories and dynamical theories. In both of these categories, polar stratospheric clouds (PSCs) are taken as part of the essential basis. Besides, all the dynamical theories are based upon temperature changes. Since formation of the PSCs is highly temperature-dependent, it has been concluded from recent research (e.g. see Kawahira and Hirooka) that temperature changes are a cause, not a result of ozone depletion in polar regions. On this basis, formulations are developed that represent short-term and long-term temperature variations in the polar regions due to natural processes. These variations, which are confined to a limited area around each pole, include specific oscillations with periods ranging from ∼ 2 years up to ∼ 218,597 years. Polar ozone variations are normally expected to be influenced by these temperature oscillations. It is, therefore, apparent that the generally decreasing trend observed in mean October ozone column at Halley Bay (76 deg. S, 27 deg. W) from 1956 up to 1987 is mostly caused by the decreasing phase of a combination of two natural temperature oscillations, one with a period of ∼ 70-80 years and the other with a period of ∼ 160-180 years. Contributions of other natural temperature oscillations are also mentioned and briefly discussed. (author). 35 refs, 4 figs

  2. Non-uniformity calibration for MWIR polarization imagery obtained with integrated microgrid polarimeters

    Science.gov (United States)

    Liu, Hai-Zheng; Shi, Ze-Lin; Feng, Bin; Hui, Bin; Zhao, Yao-Hong

    2016-03-01

    Integrating microgrid polarimeters on focal plane array (FPA) of an infrared detector causes non-uniformity of polarization response. In order to reduce the effect of polarization non-uniformity, this paper constructs an experimental setup for capturing raw flat-field images and proposes a procedure for acquiring non-uniform calibration (NUC) matrix and calibrating raw polarization images. The proposed procedure takes the incident radiation as a polarization vector and offers a calibration matrix for each pixel. Both our matrix calibration and two-point calibration are applied to our mid-wavelength infrared (MWIR) polarization imaging system with integrated microgrid polarimeters. Compared with two point calibration, our matrix calibration reduces non-uniformity by 30 40% under condition of flat-field data test with polarization. The ourdoor scene observation experiment indicates that our calibration can effectively reduce polarization non-uniformity and improve the image quality of our MWIR polarization imaging system.

  3. A simplified model of the source channel of the Leksell GammaKnife tested with PENELOPE

    OpenAIRE

    Al-Dweri, Feras M. O.; Lallena, Antonio M.; Vilches, Manuel

    2004-01-01

    Monte Carlo simulations using the code PENELOPE have been performed to test a simplified model of the source channel geometry of the Leksell GammaKnife$^{\\circledR}$. The characteristics of the radiation passing through the treatment helmets are analysed in detail. We have found that only primary particles emitted from the source with polar angles smaller than 3$^{\\rm o}$ with respect to the beam axis are relevant for the dosimetry of the Gamma Knife. The photons trajectories reaching the out...

  4. Inspection from outside of weld bead on tubes by gamma absorptiometry

    International Nuclear Information System (INIS)

    Heintz, L.; Lefevre, C.; Bergey, C.

    1983-07-01

    In this method used when it is impossible to place the gamma source inside the tube, the gamma rays pass through the tube twice. The thickness of the weld bead is determined by only one coordinate of space: the polar angle in the plane of the weld. The method was tested with an uranium ring with machined defects. The position of the defects was determined with an accuracy of 1 degree and resolution is of the order of the tube thickness [fr

  5. Polarized coincidence electroproduction

    International Nuclear Information System (INIS)

    Heimann, R.L.

    1975-03-01

    A study is made of the inclusive electroproduction of single hadrons off a polarized target. Bjorken scaling laws and the hadron azimuthal distribution are derived from the quark parton model. The polarization asymmetries scale when the target spin is along the direction of the virtual photon, and (apart from significant exception) vanish for transverse spin. These results have a simple explanation; emphasis is given both to the general mathematical formalism and to intuitive physical reasoning. Through this framework other cases are considered: quarks with anomalous magnetic moment; renormalization group effects and asymptotic freedom; production of vector mesons (whose spin state is analysed by their decay); relation to large transverse momentum hadron production; and a covariant parton model calculation. Spin 0 partons and Regge singularities are also considered. All of these cases (apart from the last two) modify the pattern of conclusions. Vector meson production shows polarization enhancements in the density matrix element rhosub(0+); the renormalization group approach does not lead to any significant suppressions. They are also less severe in parton models for large Psub(T) hadrons, and are not supported by the covariantly formulated calculation. The origins of these differences are isolated and used to exemplify the sensitivity polarized hadron electroproduction has to delicate detail that is otherwise concealed. (author)

  6. Optical neutron polarizers

    International Nuclear Information System (INIS)

    Hayter, J.B.

    1990-01-01

    A neutron wave will be refracted by an appropriately varying potential. Optical neutron polarizers use spatially varying, spin- dependent potentials to refract neutrons of opposite spin states into different directions, so that an unpolarized beam will be split into two beams of complementary polarization by such a device. This paper will concentrate on two methods of producing spin-dependent potentials which are particularly well-suited to polarizing cold neutron beams, namely thin-film structures and field-gradient techniques. Thin-film optical devices, such as supermirror multilayer structures, are usually designed to deviate only one spin-state, so that they offer the possibility of making insertion (transmission) polarizers. Very good supermirrors may now be designed and fabricated, but it is not always straightforward to design mirror-based devices which are useful in real (divergent beam) applications, and some practical configurations will be discussed. Field-gradient devices, which are usually based on multipolar magnets, have tended to be too expensive for general use, but this may change with new developments in superconductivity. Dipolar and hexapolar configurations will be considered, with emphasis on the focusing characteristics of the latter. 21 refs., 7 figs

  7. Titan Polar Landscape Evolution

    Science.gov (United States)

    Moore, Jeffrey M.

    2016-01-01

    With the ongoing Cassini-era observations and studies of Titan it is clear that the intensity and distribution of surface processes (particularly fluvial erosion by methane and Aeolian transport) has changed through time. Currently however, alternate hypotheses substantially differ among specific scenarios with respect to the effects of atmospheric evolution, seasonal changes, and endogenic processes. We have studied the evolution of Titan's polar region through a combination of analysis of imaging, elevation data, and geomorphic mapping, spatially explicit simulations of landform evolution, and quantitative comparison of the simulated landscapes with corresponding Titan morphology. We have quantitatively evaluated alternate scenarios for the landform evolution of Titan's polar terrain. The investigations have been guided by recent geomorphic mapping and topographic characterization of the polar regions that are used to frame hypotheses of process interactions, which have been evaluated using simulation modeling. Topographic information about Titan's polar region is be based on SAR-Topography and altimetry archived on PDS, SAR-based stereo radar-grammetry, radar-sounding lake depth measurements, and superposition relationships between geomorphologic map units, which we will use to create a generalized topographic map.

  8. The polarized EMC effect

    Energy Technology Data Exchange (ETDEWEB)

    W. Bentz; I. C. Cloet; A. W. Thomas

    2007-02-01

    We calculate both the spin independent and spin dependent nuclear structure functions in an effective quark theory. The nucleon is described as a composite quark-diquark state, and the nucleus is treated in the mean field approximation. We predict a sizable polarized EMC effect, which could be confirmed in future experiments.

  9. Polarizer reflectivity variations

    International Nuclear Information System (INIS)

    Ozarski, R.G.; Prior, J.

    1980-01-01

    On Shiva the beam energy along the chain is monitored using available reflections and/or transmission through beam steering, splitting, and polarizing optics without the intrusion of any additional glass for diagnostics. On the preamp table the diagnostic signal is obtained from the signal transmitted through turning mirrors. At the input of each chain the signal is obtained from the transmission through one of the mirrors used for the chain input alignment sensor (CHIP). At the chain output the transmission through the final turning mirror is used. These diagnostics have proved stable and reliable. However, one of the prime diagnostic locations is at the output of the beta rod. The energy at this location is measured by collecting small reflections from the last polarizer surface of the beta Pockels cell polarizer package. Unfortunately, calibration of this diagnostic has varied randomly, seldom remaining stable for a week or more. The cause of this fluctuation has been investigated for the past year and'it has been discovered that polarizer reflectivity varies with humidity. This report will deal with the possible causes that were investigated, the evidence that humidity is causing the variation, and the associated mechanism

  10. Spin-polarized photoemission

    International Nuclear Information System (INIS)

    Johnson, Peter D.

    1997-01-01

    Spin-polarized photoemission has developed into a versatile tool for the study of surface and thin film magnetism. In this review, we examine the methodology of the technique and its application to a number of different problems, including both valence band and core level studies. After a detailed review of spin-polarization measurement techniques and the related experimental requirements we consider in detail studies of the bulk properties both above and below the Curie temperature. This section also includes a discussion of observations relating to unique metastable phases obtained via epitaxial growth. The application of the technique to the study of surfaces, both clean and adsorbate covered, is reviewed. The report then examines, in detail, studies of the spin-polarized electronic structure of thin films and the related interfacial magnetism. Finally, observations of spin-polarized quantum well states in non-magnetic thin films are discussed with particular reference to their mediation of the oscillatory exchange coupling in related magnetic multilayers. (author)

  11. Polarization of Bremsstrahlung

    International Nuclear Information System (INIS)

    Miller, J.

    1957-01-01

    The numerical results for the polarization of Bremsstrahlung are presented. The multiple scattering of electrons in the target is taken into account. The angular-and photon energy dependences are seen on the curves for an incident 25 MeV electron energy. (Author) [fr

  12. No More Polarization, Please!

    DEFF Research Database (Denmark)

    Hansen, Mia Reinholt

    and the increasing levels of complexities it entails, such polarization is not fruitful in the attempt to explain motivation of organizational members. This paper claims that a more nuanced perspective on motivation, acknowledging the co-existence of intrinsic and extrinsic motivation, the possible interaction...

  13. DESY: HERA polarization

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    The new HERA electron-proton collider at DESY in Hamburg achieved the first luminosity for electron-proton collisions on 19 October last year. Only one month later, on 20 November, HERA passed another important milestone with the observation of transverse electron polarization

  14. Polarized Neutron Scattering

    OpenAIRE

    Roessli, B.; Böni, P.

    2000-01-01

    The technique of polarized neutron scattering is reviewed with emphasis on applications. Many examples of the usefulness of the method in various fields of physics are given like the determination of spin density maps, measurement of complex magnetic structures with spherical neutron polarimetry, inelastic neutron scattering and separation of coherent and incoherent scattering with help of the generalized XYZ method.

  15. DESY: HERA polarization

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1992-03-15

    The new HERA electron-proton collider at DESY in Hamburg achieved the first luminosity for electron-proton collisions on 19 October last year. Only one month later, on 20 November, HERA passed another important milestone with the observation of transverse electron polarization.

  16. Graphics of polar figure

    International Nuclear Information System (INIS)

    Macias B, L.R.

    1991-11-01

    The objective of this work, is that starting from a data file coming from a spectra that has been softened, and of the one that have been generated its coordinates to project it in stereographic form, to create the corresponding polar figure making use of the Cyber computer of the ININ by means of the GRAPHOS package. This work only requires a Beta, Fi and Intensity (I) enter data file. It starts of the existence of a softened spectra of which have been generated already with these data, making use of some language that in this case was FORTRAN for the Cyber computer, a program is generated supported in the Graphos package that allows starting of a reading of the Beta, Fi, I file, to generate the points in a stereographic projection and that it culminates with the graph of the corresponding polar figure. The program will request the pertinent information that is wanted to capture in the polar figure just as: date, name of the enter file, indexes of the polar figure, number of levels, radio of the stereographic projection (cms.), crystalline system to which belongs the sample, name the neuter graph file by create and to add the own general data. (Author)

  17. Realization of beam polarization at the linear collider and its application to EW processes

    Energy Technology Data Exchange (ETDEWEB)

    Franco-Sollova, F.

    2006-07-15

    The use of beam polarization at the future ILC e{sup +}e{sup -} linear collider will benefit the physics program significantly. This thesis explores three aspects of beam polarization: the application of beam polarization to the study of electroweak processes, the precise measurement of the beam polarization, and finally, the production of polarized positrons at a test beam experiment. In the first part of the thesis the importance of beam polarization at the future ILC is exhibited: the benefits of employing transverse beam polarization (in both beams) for the measurement of triple gauge boson couplings (TGCs) in the W-pair production process are studied. The sensitivity to anomalous TGC values is compared for the cases of transverse and longitudinal beam polarization at a center of mass energy of 500 GeV. Due to the suppressed contribution of the t-channel {nu} exchange, the sensitivity is higher for longitudinal polarization. For some physics analyses the usual polarimetry techniques do not provide the required accuracy for the measurement of the beam polarization (around 0.25% with Compton polarimetry). The second part of the thesis deals with a complementary method to measure the beam polarization employing physics data acquired with two polarization modes. The process of single-W production is chosen due to its high cross section. The expected precision for 500 fb{sup -1} and W{yields}{mu}{nu} decays only, is {delta}P{sub e{sup -}}/P{sub e{sup -}}=0.26% and {delta}P{sub e{sup +}}/P{sub e{sup +}}=0.33%, which can be further improved by employing additional W-decay channels. The first results of an attempt to produce polarized positrons at the E-166 experiment are shown in the last part of the thesis. The E-166 experiment, located at the Final Focus Test Beam at SLAC's LINAC employs a helical undulator to induce the emission of circularly polarized gamma rays by the beam electrons. These gamma rays are converted into longitudinally polarized electron

  18. Polarized light and optical measurement

    CERN Document Server

    Clarke, D N; Ter Haar, D

    2013-01-01

    Polarized Light and Optical Measurement is a five-chapter book that begins with a self-consistent conceptual picture of the phenomenon of polarization. Chapter 2 describes a number of interactions of light and matter used in devising optical elements in polarization studies. Specific optical elements are given in Chapter 3. The last two chapters explore the measurement of the state of polarization and the various roles played in optical instrumentation by polarization and polarization-sensitive elements. This book will provide useful information in this field of interest for research workers,

  19. Polarization Smoothing Generalized MUSIC Algorithm with Polarization Sensitive Array for Low Angle Estimation.

    Science.gov (United States)

    Tan, Jun; Nie, Zaiping

    2018-05-12

    Direction of Arrival (DOA) estimation of low-altitude targets is difficult due to the multipath coherent interference from the ground reflection image of the targets, especially for very high frequency (VHF) radars, which have antennae that are severely restricted in terms of aperture and height. The polarization smoothing generalized multiple signal classification (MUSIC) algorithm, which combines polarization smoothing and generalized MUSIC algorithm for polarization sensitive arrays (PSAs), was proposed to solve this problem in this paper. Firstly, the polarization smoothing pre-processing was exploited to eliminate the coherence between the direct and the specular signals. Secondly, we constructed the generalized MUSIC algorithm for low angle estimation. Finally, based on the geometry information of the symmetry multipath model, the proposed algorithm was introduced to convert the two-dimensional searching into one-dimensional searching, thus reducing the computational burden. Numerical results were provided to verify the effectiveness of the proposed method, showing that the proposed algorithm has significantly improved angle estimation performance in the low-angle area compared with the available methods, especially when the grazing angle is near zero.

  20. Gamma ray polarimetry using a position sensitive germanium detector

    CERN Document Server

    Kroeger, R A; Kurfess, J D; Phlips, B F

    1999-01-01

    Imaging gamma-ray detectors make sensitive polarimeters in the Compton energy regime by measuring the scatter direction of gamma rays. The principle is to capitalize on the angular dependence of the Compton scattering cross section to polarized gamma rays and measure the distribution of scatter directions within the detector. This technique is effective in a double-sided germanium detector between roughly 50 keV and 1 MeV. This paper reviews device characteristics important to the optimization of a Compton polarimeter, and summarizes measurements we have made using a device with a 5x5 cm active area, 1 cm thickness, and strip-electrodes on a 2 mm pitch.

  1. Ultra-wideband reflective polarization converter based on anisotropic metasurface

    Science.gov (United States)

    Wu, Jia-Liang; Lin, Bao-Qin; Da, Xin-Yu

    2016-08-01

    In this paper, we propose an ultra-wideband reflective linear cross-polarization converter based on anisotropic metasurface. Its unit cell is composed of a square-shaped resonator with intersectant diagonal and metallic ground sheet separated by dielectric substrate. Simulated results show that the converter can generate resonances at four frequencies under normal incident electromagnetic (EM) wave, leading to the bandwidth expansion of cross-polarization reflection. For verification, the designed polarization converter is fabricated and measured. The measured and simulated results agree well with each other, showing that the fabricated converter can convert x- or y-polarized incident wave into its cross polarized wave in a frequency range from 7.57 GHz to 20.46 GHz with a relative bandwidth of 91.2%, and the polarization conversion efficiency is greater than 90%. The proposed polarization converter has a simple geometry but an ultra wideband compared with the published designs, and hence possesses potential applications in novel polarization-control devices. Project supported by the National Natural Science Foundation of China (Grant Nos. 61471387, 61271250, and 61571460).

  2. Ultra-wideband reflective polarization converter based on anisotropic metasurface

    International Nuclear Information System (INIS)

    Wu Jia-Liang; Lin Bao-Qin; Da Xin-Yu

    2016-01-01

    In this paper, we propose an ultra-wideband reflective linear cross-polarization converter based on anisotropic metasurface. Its unit cell is composed of a square-shaped resonator with intersectant diagonal and metallic ground sheet separated by dielectric substrate. Simulated results show that the converter can generate resonances at four frequencies under normal incident electromagnetic (EM) wave, leading to the bandwidth expansion of cross-polarization reflection. For verification, the designed polarization converter is fabricated and measured. The measured and simulated results agree well with each other, showing that the fabricated converter can convert x - or y -polarized incident wave into its cross polarized wave in a frequency range from 7.57 GHz to 20.46 GHz with a relative bandwidth of 91.2%, and the polarization conversion efficiency is greater than 90%. The proposed polarization converter has a simple geometry but an ultra wideband compared with the published designs, and hence possesses potential applications in novel polarization-control devices. (paper)

  3. Time-of-flight and vector polarization analysis for diffuse neutron scattering

    International Nuclear Information System (INIS)

    Schweika, W.

    2003-01-01

    The potential of pulsed neutron sources for diffuse scattering including time-of-flight (TOF) and polarization analysis is discussed in comparison to the capabilities of the present instrument diffuse neutron scattering at the research center Juelich. We present first results of a new method for full polarization analysis using precessing neutron polarization. A proposal is made for a new type of instrument at pulsed sources, which allows for vector polarization analysis in TOF instruments with multi-detectors

  4. Polarized nuclear target based on parahydrogen induced polarization

    OpenAIRE

    Budker, D.; Ledbetter, M. P.; Appelt, S.; Bouchard, L. S.; Wojtsekhowski, B.

    2012-01-01

    We discuss a novel concept of a polarized nuclear target for accelerator fixed-target scattering experiments, which is based on parahydrogen induced polarization (PHIP). One may be able to reach a 33% free-proton polarization in the ethane molecule. The potential advantages of such a target include operation at zero magnetic field, fast ($\\sim$100 Hz) polarization reversal, and operation with large intensity of an electron beam.

  5. System for gamma-gamma formation density logging while drilling

    International Nuclear Information System (INIS)

    Paske, W.C.

    1991-01-01

    The patent relates to a system for logging subterranean formations for the determination of formation density by using gamma radiation. Gamma ray source and detection means are disposed within a housing adapted for positioning within a borehole for the emission and detection of gamma rays propagating through earth formations and borehole drilling fluid. The gamma ray detection means comprises first and second gamma radiation sensors geometrically disposed within the housing, the same longitudinal distance from the gamma ray source and diametrically opposed in a common plane. A formation matrix density output signal is produced in proportion to the output signal from each of the gamma ray sensors and in conjunction with certain constants established by the geometrical configuration of the sensors relative to the gamma ray source and the borehole diameter. Formation density is determined without regard to the radial position of the logging probe within the borehole in a measuring while drilling mode. 6 figs

  6. Laser-induced nuclear orientation and gamma anisotropy in sodium

    International Nuclear Information System (INIS)

    Pappas, P.G.

    1980-12-01

    The use of laser optical pumping to induce nuclear orientation in several isotopes and one isomer of atomic sodium vapor is described. Essentially complete nuclear polarization, P > 90%, has been achieved in stable 23 Na when pumping with modest laser intensities (I approx. = 10 mW/cm 2 ). The volume of the sample cell was approximately 10 cc, and was filled with a sodium density of about 10'' atoms/cc. Complete coverage of the Doppler distribution was accomplished with the use of trace amounts (less than or equal to 1 torr) of argon buffer gas to induce velocity changing collisions. A theoretical model which accurately predicts the amount of polarization is developed. The orientation of nuclei which are unstable to gamma decay can manifest itself in anisotropic gamma ray emission. This anisotropy can be used to measure isotope and isomer shifts, from which nuclear properties can be derived. Gamma anisotropy was observed in two systems, 22 Na and /sup 24m/Na. From the observed anisotropy in /sup 24m/Na, a negative sign for the g factor is determined. Values are derived for the magnetic moment, μ = 2.56 +- 0.64 nm, and the isomer shift, deltaν/sub 24m/ = 288 +- 191 MHz (D1 line). A model is described which relates various laser and fubber gas parameters to the observed gamma anisotropy lineshape. This model facilitates the extraction of physical parameters from knowledge of the laser frequency at which the anisotropy is a maximum

  7. Experiments with Fermilab polarized proton and polarized antiproton beams

    International Nuclear Information System (INIS)

    Yokosawa, A.

    1990-01-01

    We summarize activities concerning the Fermilab polarized beams. They include a brief description of the polarized-beam facility, measurements of beam polarization by polarimeters, asymmetry measurements in the π degree production at high p perpendicular and in the Λ (Σ degree), π ± , π degree production at large x F , and Δσ L (pp, bar pp) measurements. 18 refs

  8. NUCLEON POLARIZATION IN 3-BODY MODELS OF POLARIZED LI-6

    NARCIS (Netherlands)

    SCHELLINGERHOUT, NW; KOK, LP; COON, SA; ADAM, RM

    1993-01-01

    Just as He-3 --> can be approximately characterized as a polarized neutron target, polarized Li-6D has been advocated as a good isoscalar nuclear target for the extraction of the polarized gluon content of the nucleon. The original argument rests upon a presumed ''alpha + deuteron'' picture of Li-6,

  9. ESCL8R and LEVIT8R: interactive graphical analysis of {gamma}-{gamma} and {gamma}-{gamma}-{gamma} coincidence data for level schemes

    Energy Technology Data Exchange (ETDEWEB)

    Radford, D C [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.

    1992-08-01

    The extraction of complete and consistent nuclear level schemes from high-fold coincidence data will require intelligent computer programs. These will need to present the relevant data in an easily assimilated manner, keep track of all {gamma}-ray assignments and expected coincidence intensities, and quickly find significant discrepancies between a proposed level scheme and the data. Some steps in this direction have been made at Chalk River. The programs ESCL8R and LEVIT8R, for analysis of two-fold and three-fold data sets respectively, allow fast and easy inspection of the data, and compare the results to expectations calculations on the basis of a proposed level scheme. Least-squares fits directly to the 2D and/or 3D data, with the intensities and energies of the level scheme transitions as parameters, allow fast and easy extraction of the optimum physics results. (author). 4 refs., 3 figs.

  10. Design Study for Direction Variable Compton Scattering Gamma Ray

    Science.gov (United States)

    Kii, T.; Omer, M.; Negm, H.; Choi, Y. W.; Kinjo, R.; Yoshida, K.; Konstantin, T.; Kimura, N.; Ishida, K.; Imon, H.; Shibata, M.; Shimahashi, K.; Komai, T.; Okumura, K.; Zen, H.; Masuda, K.; Hori, T.; Ohgaki, H.

    2013-03-01

    A monochromatic gamma ray beam is attractive for isotope-specific material/medical imaging or non-destructive inspection. A laser Compton scattering (LCS) gamma ray source which is based on the backward Compton scattering of laser light on high-energy electrons can generate energy variable quasi-monochromatic gamma ray. Due to the principle of the LCS gamma ray, the direction of the gamma beam is limited to the direction of the high-energy electrons. Then the target object is placed on the beam axis, and is usually moved if spatial scanning is required. In this work, we proposed an electron beam transport system consisting of four bending magnets which can stick the collision point and control the electron beam direction, and a laser system consisting of a spheroidal mirror and a parabolic mirror which can also stick the collision point. Then the collision point can be placed on one focus of the spheroid. Thus gamma ray direction and collision angle between the electron beam and the laser beam can be easily controlled. As the results, travelling direction of the LCS gamma ray can be controlled under the limitation of the beam transport system, energy of the gamma ray can be controlled by controlling incident angle of the colliding beams, and energy spread can be controlled by changing the divergence of the laser beam.

  11. Modular gamma systems

    International Nuclear Information System (INIS)

    Millegan, D.R.; Nixon, K.V.

    1982-01-01

    Nuclear safeguards requires sensitive, easily operated instruments for rapid inspection of personnel and vehicles to ensure that no uranium or plutonium is being diverted. Two portable gamma-ray detection systems have been developed. The Modular Gamma System (MGS) is very sensitive and two or more systems can be connected for even better performance. The multiunit configuration can be deployed by motor vehicle for search of large areas too extensive to search on foot. The Programmable Rate Monitor (PRM) is less sensitive but much smaller and therefore is more suitable for search of vehicles, personnel, or smaller areas. The PRM is programmable, which implements measurement and alarm algorithms for individual applications

  12. Proprioceptive evoked gamma oscillations

    DEFF Research Database (Denmark)

    Arnfred, S.M.; Hansen, Lars Kai; Parnas, J.

    2007-01-01

    A proprioceptive stimulus consisting of a weight change of a handheld load has recently been shown to elicit an evoked potential. Previously, somatosensory gamma oscillations have only been evoked by electrical stimuli. We conjectured that a natural proprioceptive stimulus also would be able...... to evoke gamma oscillations. EEG was recorded using 64 channels in 14 healthy subjects. In each of three runs a stimulus of 100 g load increment in each hand was presented in 120 trials. Data were wavelet transformed and runs collapsed. Inter-trial phase coherence (ITPC) was computed as the best measure...

  13. Gamma-Ray Bursts

    Science.gov (United States)

    Pellizza, L. J.

    Gamma-ray bursts are the brightest transient sources in the gamma-ray sky. Since their discovery in the late 1960s, the investigation of the astrophysical sys- tems in which these phenomena take place, and the physical mechanisms that drive them, has become a vast and prolific area of modern astrophysics. In this work I will briefly describe the most relevant observations of these sources, and the models that describe their nature, emphasizing on the in- vestigations about the progenitor astrophysical systems. FULL TEXT IN SPANISH

  14. Gamma Ray Bursts

    Science.gov (United States)

    Gehrels, Neil; Meszaros, Peter

    2012-01-01

    Gamma-ray bursts (GRBs) are bright flashes of gamma-rays coming from the cosmos. They occur roughly once per day ,last typically lOs of seconds and are the most luminous events in the universe. More than three decades after their discovery, and after pioneering advances from space and ground experiments, they still remain mysterious. The launch of the Swift and Fermi satellites in 2004 and 2008 brought in a trove of qualitatively new data. In this review we survey the interplay between these recent observations and the theoretical models of the prompt GRB emission and the subsequent afterglows.

  15. A novel fully integrated handheld gamma camera

    International Nuclear Information System (INIS)

    Massari, R.; Ucci, A.; Campisi, C.; Scopinaro, F.; Soluri, A.

    2016-01-01

    In this paper, we present an innovative, fully integrated handheld gamma camera, namely designed to gather in the same device the gamma ray detector with the display and the embedded computing system. The low power consumption allows the prototype to be battery operated. To be useful in radioguided surgery, an intraoperative gamma camera must be very easy to handle since it must be moved to find a suitable view. Consequently, we have developed the first prototype of a fully integrated, compact and lightweight gamma camera for radiopharmaceuticals fast imaging. The device can operate without cables across the sterile field, so it may be easily used in the operating theater for radioguided surgery. The prototype proposed consists of a Silicon Photomultiplier (SiPM) array coupled with a proprietary scintillation structure based on CsI(Tl) crystals. To read the SiPM output signals, we have developed a very low power readout electronics and a dedicated analog to digital conversion system. One of the most critical aspects we faced designing the prototype was the low power consumption, which is mandatory to develop a battery operated device. We have applied this detection device in the lymphoscintigraphy technique (sentinel lymph node mapping) comparing the results obtained with those of a commercial gamma camera (Philips SKYLight). The results obtained confirm a rapid response of the device and an adequate spatial resolution for the use in the scintigraphic imaging. This work confirms the feasibility of a small gamma camera with an integrated display. This device is designed for radioguided surgery and small organ imaging, but it could be easily combined into surgical navigation systems.

  16. A novel fully integrated handheld gamma camera

    Energy Technology Data Exchange (ETDEWEB)

    Massari, R.; Ucci, A.; Campisi, C. [Biostructure and Bioimaging Institute (IBB), National Research Council of Italy (CNR), Rome (Italy); Scopinaro, F. [University of Rome “La Sapienza”, S. Andrea Hospital, Rome (Italy); Soluri, A., E-mail: alessandro.soluri@ibb.cnr.it [Biostructure and Bioimaging Institute (IBB), National Research Council of Italy (CNR), Rome (Italy)

    2016-10-01

    In this paper, we present an innovative, fully integrated handheld gamma camera, namely designed to gather in the same device the gamma ray detector with the display and the embedded computing system. The low power consumption allows the prototype to be battery operated. To be useful in radioguided surgery, an intraoperative gamma camera must be very easy to handle since it must be moved to find a suitable view. Consequently, we have developed the first prototype of a fully integrated, compact and lightweight gamma camera for radiopharmaceuticals fast imaging. The device can operate without cables across the sterile field, so it may be easily used in the operating theater for radioguided surgery. The prototype proposed consists of a Silicon Photomultiplier (SiPM) array coupled with a proprietary scintillation structure based on CsI(Tl) crystals. To read the SiPM output signals, we have developed a very low power readout electronics and a dedicated analog to digital conversion system. One of the most critical aspects we faced designing the prototype was the low power consumption, which is mandatory to develop a battery operated device. We have applied this detection device in the lymphoscintigraphy technique (sentinel lymph node mapping) comparing the results obtained with those of a commercial gamma camera (Philips SKYLight). The results obtained confirm a rapid response of the device and an adequate spatial resolution for the use in the scintigraphic imaging. This work confirms the feasibility of a small gamma camera with an integrated display. This device is designed for radioguided surgery and small organ imaging, but it could be easily combined into surgical navigation systems.

  17. Source of spin polarized electrons

    International Nuclear Information System (INIS)

    Pierce, D.T.; Meier, F.A.; Siegmann, H.C.

    1976-01-01

    A method is described of producing intense beams of polarized free electrons in which a semiconductor with a spin orbit split valence band and negative electron affinity is used as a photocathode and irradiated with circularly polarized light

  18. Linearly polarized photons at ELSA

    Energy Technology Data Exchange (ETDEWEB)

    Eberhardt, Holger [Physikalisches Institut, Universitaet Bonn (Germany)

    2009-07-01

    To investigate the nucleon resonance regime in meson photoproduction, double polarization experiments are currently performed at the electron accelerator ELSA in Bonn. The experiments make use of a polarized target and circularly or linearly polarized photon beams. Linearly polarized photons are produced by coherent bremsstrahlung from an accurately aligned diamond crystal. The orientation of the crystal with respect to the electron beam is measured using the Stonehenge-Technique. Both, the energy of maximum polarization and the plane of polarization, can be deliberately chosen for the experiment. The linearly polarized beam provides the basis for the measurement of azimuthal beam asymmetries, such as {sigma} (unpolarized target) and G (polarized target). These observables are extracted in various single and multiple meson photoproduction channels.

  19. Continuous variable polarization entanglement, experiment and analysis

    International Nuclear Information System (INIS)

    Bowen, Warwick P; Treps, Nicolas; Schnabel, Roman; Ralph, Timothy C; Lam, Ping Koy

    2003-01-01

    We generate and characterize continuous variable polarization entanglement between two optical beams. We first produce quadrature entanglement, and by performing local operations we transform it into a polarization basis. We extend two entanglement criteria, the inseparability criteria proposed by Duan et al (2000 Phys. Rev. Lett. 84 2722) and the Einstein-Podolsky-Rosen (EPR) paradox criteria proposed by Reid and Drummond (1988 Phys. Rev. Lett. 60 2731), to Stokes operators; and use them to characterize the entanglement. Our results for the EPR paradox criteria are visualized in terms of uncertainty balls on the Poincare sphere. We demonstrate theoretically that using two quadrature entangled pairs it is possible to entangle three orthogonal Stokes operators between a pair of beams, although with a bound √3 times more stringent than for the quadrature entanglement

  20. Continuous variable polarization entanglement, experiment and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Bowen, Warwick P [Department of Physics, Faculty of Science, Australian National University, ACT 0200 (Australia); Treps, Nicolas [Department of Physics, Faculty of Science, Australian National University, ACT 0200 (Australia); Schnabel, Roman [Department of Physics, Faculty of Science, Australian National University, ACT 0200 (Australia); Ralph, Timothy C [Department of Physics, Centre for Quantum Computer Technology, University of Queensland, St Lucia, QLD 4072 (Australia); Lam, Ping Koy [Department of Physics, Faculty of Science, Australian National University, ACT 0200 (Australia)

    2003-08-01

    We generate and characterize continuous variable polarization entanglement between two optical beams. We first produce quadrature entanglement, and by performing local operations we transform it into a polarization basis. We extend two entanglement criteria, the inseparability criteria proposed by Duan et al (2000 Phys. Rev. Lett. 84 2722) and the Einstein-Podolsky-Rosen (EPR) paradox criteria proposed by Reid and Drummond (1988 Phys. Rev. Lett. 60 2731), to Stokes operators; and use them to characterize the entanglement. Our results for the EPR paradox criteria are visualized in terms of uncertainty balls on the Poincare sphere. We demonstrate theoretically that using two quadrature entangled pairs it is possible to entangle three orthogonal Stokes operators between a pair of beams, although with a bound {radical}3 times more stringent than for the quadrature entanglement.

  1. Plasmonic vortex generator without polarization dependence

    Science.gov (United States)

    Wang, Han; Liu, Lixia; Liu, Chunxiang; Li, Xing; Wang, Shuyun; Xu, Qing; Teng, Shuyun

    2018-03-01

    In view of the limitations of vortex generators with polarization dependence at present, we propose a plasmonic vortex generator composed of rectangular holes etched in silver film, in which the optical vortex can be generated under arbitrary linearly polarized light illumination. Two sets of rectangular holes are arranged equidistantly on a circle and rotate in postulate directions. Theoretical analysis provides the design principle for the vortex generator, and numerical simulations give guidance on designating the vortex generator parameters. Experimental measurements verify the performance of the proposed vortex generator. Moreover, two alternative structures for the generation of a plasmonic vortex are also provided in this paper. The resulting perfect vortex, compact structure and flexible illumination conditions will lead to wide applications of this plasmonic vortex generator.

  2. Polarized differential-phase laser scanning microscope

    International Nuclear Information System (INIS)

    Chou Chien; Lyu, C.-W.; Peng, L.-C.

    2001-01-01

    A polarized differential-phase laser scanning microscope, which combines a polarized optical heterodyne Mach-Zehnder interferometer and a differential amplifier to scan the topographic image of a surface, is proposed. In the experiment the differential amplifier, which acts as a PM-AM converter, in the experiment, converting phase modulation (PM) into amplitude modulation (AM). Then a novel, to our knowledge, phase demodulator was proposed and implemented for the differential-phase laser scanning microscope. An optical grating (1800 lp/mm) was imaged. The lateral and the depth resolutions of the imaging system were 0.5 μm and 1 nm, respectively. The detection accuracy, which was limited by the reflectivity variation of the test surface, is discussed

  3. Influence of the rock heterogeneity on the results of gamma-gamma logging

    International Nuclear Information System (INIS)

    Umiastowski, K.; Buniak, M.

    1977-01-01

    The influence of the grain size of granular rock and that of the empty holes size of porous rock on the results of gamma-gamma measurements was investigated. Monte-Carlo calculations and experiments were performed to establish this influence. For the grain (or empty holes) size greater than about 10mm the significant influence on the results of density measurements was found if a 137 Cs source was used. This effect is greater for the dry rock than for the water-saturated one. Formulae enabling the correct density value to be found, if the grain size is known, were proposed. (author)

  4. Optical telescope BIRT in ORIGIN for gamma ray burst observing

    DEFF Research Database (Denmark)

    Content, Robert; Content, Robert; Sharples, Ray

    2012-01-01

    The ORIGIN concept is a space mission with a gamma ray, an X-ray and an optical telescope to observe the gamma ray bursts at large Z to determine the composition and density of the intergalactic matter in the line of sight. It was an answer to the ESA M3 call for proposal. The optical telescope i...... length. All 3 instruments use the same 2k x 2k detector simultaneously so that telescope pointing and tip-tilt control of a fold mirror permit to place the gamma ray burst on the desired instrument without any other mechanism. © 2012 SPIE....

  5. Detailed analysis of evolution of the state of polarization in all-fiber polarization transformers.

    Science.gov (United States)

    Zhu, Xiushan; Jain, Ravinder K

    2006-10-30

    We present a detailed analysis of key attributes and performance characteristics of controllably-spun birefringent-fiber-based all-fiber waveplates or "all fiber polarization transformers" (AFPTs), first proposed and demonstrated by Huang [11]; these AFPTs consist essentially of a long carefully-designed "spin-twisted" high-birefringence fiber, fabricated by slowly varying the spin rate of a birefringent fiber preform (either from very fast to very slow or vice versa) while the fiber is being drawn. The evolution of the eigenstate from a linear polarization state to a circular polarization state, induced by slow variation of the intrinsic structure from linear anisotropy at the unspun end to circular anisotropy at the fast-spun end, enables the AFPT to behave like an all-fiber quarter-wave plate independent of the wavelength of operation. Power coupling between local eigenstates causes unique evolution of the polarization state along the fiber, and has been studied to gain insight into - as well as to understand detailed characteristics of -- the polarization transformation behavior. This has been graphically illustrated via plots of the relative power in these local eigenstates as a function of distance along the length of the fiber and plots of the extinction ratio of the output state of polarization (SOP) as a function of distance and the normalized spin rate. Deeper understanding of such polarization transformers has been further elucidated by quantitative calculations related to two crucial requirements for fabricating practical AFPT devices. Our calculations have also indicated that the polarization mode dispersion behaviour of the AFPT is much smaller than that of the original birefringent fiber. Finally, a specific AFPT was experimentally investigated at two widely-separated wavelengths (1310 nm and 1550 nm) of interest in telecommunications systems applications, further demonstrating and elucidating the broadband character of such AFPTs.

  6. North Polar Cap

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] This week we will be looking at five examples of laminar wind flow on the north polar cap. On Earth, gravity-driven south polar cap winds are termed 'catabatic' winds. Catabatic winds begin over the smooth expanse of the cap interior due to temperature differences between the atmosphere and the surface. Once begun, the winds sweep outward along the surface of the polar cap toward the sea. As the polar surface slopes down toward sealevel, the wind speeds increase. Catabatic wind speeds in the Antartic can reach several hundreds of miles per hour. In the images of the Martian north polar cap we can see these same type of winds. Notice the streamers of dust moving downslope over the darker trough sides, these streamers show the laminar flow regime coming off the cap. Within the trough we see turbulent clouds of dust, kicked up at the trough base as the winds slow down and enter a chaotic flow regime. The horizontal lines in these images are due to framelet overlap and lighting conditions over the bright polar cap. Image information: VIS instrument. Latitude 86.5, Longitude 64.5 East (295.5 West). 40 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen

  7. Interferon Gamma-1b Injection

    Science.gov (United States)

    Interferon gamma-1b injection is used to reduce the frequency and severity of serious infections in people with chronic ... severe, malignant osteopetrosis (an inherited bone disease). Interferon gamma-1b is in a class of medications called ...

  8. Gamma knife surgery for craniopharyngioma

    International Nuclear Information System (INIS)

    Prasad, D.; Steiner, M.; Steiner, L.

    1995-01-01

    We present our results of Gamma Knife surgery for craniopharyngioma in nine patients. The current status of surgery, radiation therapy, intracavitary instillation of radionuclides and Gamma Knife surgery in the management of craniopharyngiomas is discussed. (author)

  9. CKM angle $\\gamma$ from LHCb

    CERN Multimedia

    Smith, Jackson

    2015-01-01

    Results of the latest $\\gamma$ combination from LHCb are presented, along with the six LHCb measurements used as inputs. In addition, the anticipated precision attainable for measuring $\\gamma$ after the LHCb Upgrade is outlined

  10. A polarization stabilizer up to 12.6 krad/s with an additional function of stable state of polarization transformation

    International Nuclear Information System (INIS)

    Xiao-Guang, Zhang; Guang-Qing, Fang; Xin-Yuan, Zhao; Wen-Bo, Zhang; Li-Xia, Xi; Qian-Jin, Xiong; Xi-Xiang, Li; Guang-Yong, Zhang

    2010-01-01

    This paper reports on an experiment about a novel method of polarization stabilization. The polarization stabilizer proposed here has an additional function of polarization transformation from any state of polarization into any others. The particle swarm optimization is introduced as a control algorithm in the process of either searching or endless tracking. The tracking speed of the stabilizer is obtained up to 12.6 krad/s by using hardware we have in the laboratory, which means that we can achieve a higher speed practical polarization stabilizer if we have faster hardware. (classical areas of phenomenology)

  11. Stanford polarized atomic beam target

    International Nuclear Information System (INIS)

    Mavis, D.G.; Dunham, J.S.; Hugg, J.W.; Glavish, H.F.

    1976-01-01

    A polarized atomic beam source was used to produce an atomic hydrogen beam which was in turn used as a polarized proton target. A target density of 2 x 10'' atoms/cm 3 and a target polarization of 0.37 without the use of rf transitions were measured. These measurements indicate that a number of experiments are currently feasible with a variety of polarized target beams

  12. The MAGIC gamma-ray telescope: status and first results

    International Nuclear Information System (INIS)

    Fernandez, Enrique

    2006-01-01

    MAGIC, a 17 m diameter Cherenkov telescope for gamma ray astronomy, has recently been commissioned at the Roque de los Muchachos site in the Island of La Palma, of the Canary Islands. The telescope was proposed in 1998 with the goal of lowering the threshold of observation of gamma rays by ground detectors to 20-30 GeV energies. This paper describes its main design features, its physics objectives and its first operations

  13. Three-photon polarization ququarts: polarization, entanglement and Schmidt decompositions

    International Nuclear Information System (INIS)

    Fedorov, M V; Miklin, N I

    2015-01-01

    We consider polarization states of three photons, propagating collinearly and having equal given frequencies but with arbitrary distributed horizontal or vertical polarizations of photons. A general form of such states is a superposition of four basic three-photon polarization modes, to be referred to as the three-photon polarization ququarts (TPPQ). All such states can be considered as consisting of one- and two-photon parts, which can be entangled with each other. The degrees of entanglement and polarization, as well as the Schmidt decomposition and Stokes vectors of TPPQ are found and discussed. (paper)

  14. Polarization effects in hadron fragmentation

    International Nuclear Information System (INIS)

    Lednicky, R.

    1984-01-01

    Hadron polarization (spin alignment) and polarization asymmetry are discussed in terms of the quark recombination model with the spin-orbit interaction taken into account. It is shown that predictions of this model are at least in qualitative agreement with experimental data. Various polarization mechanisms in terms of this model and the possibility of their checking are also discussed

  15. Detection of polar vapours

    International Nuclear Information System (INIS)

    Blyth, D.A.

    1980-01-01

    Apparatus for monitoring for polar vapours in a gas consists of (i) a body member defining a passage through which a continuous stream of the gas passes; (ii) an ionising source associated with a region of the passage such that ionization of the gas stream takes place substantially only within the region and also any polar vapour molecules present therein will react with the gas formed to generate ion clusters; and (iii) an electrode for collecting ions carried by the gas stream, the electrode being positioned in the passage downstream of the region and separated from the region by a sufficient distance to ensure that no substantial number of the gas ions formed in said region remains in the gas stream at the collector electrode whilst ensuring that a substantial proportion of the ion clusters formed in the region does remain in the gas stream at the collector electrode. (author)

  16. Perspectives for polarized antiprotons

    International Nuclear Information System (INIS)

    Lenisa, Paolo

    2012-01-01

    Polarized antiprotons would open a new window in hadron physics providing access to a wealth of single and double spin observables in proton-antiproton interactions. The PAX Collaboration aims to perform the first ever measurement of the spin-dependence of the proton-antiproton cross section at the AD ring at CERN. The spin-dependence of the cross section could in principle be exploited by the spin-filtering technique for the production of a polarized antiproton beam. As a preparatory phase to the experimentation at AD, the PAX Collaboration has initiated a series of dedicated studies with protons at the COSY-ring in Juelich (Germany), aimed at the commissioning of the experimental apparatus and confirmation of the predictions for spin-filtering with protons.

  17. The Polar Cusp

    International Nuclear Information System (INIS)

    Holtet, J.A.; Egeland, A.

    1985-01-01

    The upper atmosphere at high latitudes is often called the ''earth's window to outer space.'' Through various electrodynamic coupling processes, as well as direct transfer of particles, many of the geophysical effects displayed are direct manifestations of phenomena occurring in deep space. The high latitude ionosphere also exerts a feedback on the regions of the magnetosphere and atmosphere to which it is coupled. Of particular interest are the sections of the near space known as the Polar Cusp. A vast portion of the Earth's magnetic field envelope is electrically connected to these regions. This geometry results in a spatial mapping of the magnetospheric processes and a focusing on the ionosphere. In the Polar Cusps, the solar wind plasma also has direct access to the upper atmosphere

  18. Polarized electrogowdy spacetimes censored

    International Nuclear Information System (INIS)

    Nungesser, Ernesto

    2010-01-01

    A sketch of the proof of strong cosmic censorship is presented for a class of solutions of the Einstein-Maxwell equations, those with polarized Gowdy symmetry. A key element of the argument is the observation that by means of a suitable choice of variables the central equations in this problem can be written in a form where they are identical to the central equations for general (i.e. non-polarized) vacuum Gowdy spacetimes. Using this it is seen that the results of Ringstroem on strong cosmic censorship in the vacuum case have implications for the Einstein-Maxwell case. Working out the geometrical meaning of these analytical results leads to the main conclusion.

  19. Polarized electrogowdy spacetimes censored

    Energy Technology Data Exchange (ETDEWEB)

    Nungesser, Ernesto, E-mail: ernesto.nungesser@aei.mpg.d [Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, Am Muehlenberg 1, 14476 Potsdam (Germany)

    2010-05-01

    A sketch of the proof of strong cosmic censorship is presented for a class of solutions of the Einstein-Maxwell equations, those with polarized Gowdy symmetry. A key element of the argument is the observation that by means of a suitable choice of variables the central equations in this problem can be written in a form where they are identical to the central equations for general (i.e. non-polarized) vacuum Gowdy spacetimes. Using this it is seen that the results of Ringstroem on strong cosmic censorship in the vacuum case have implications for the Einstein-Maxwell case. Working out the geometrical meaning of these analytical results leads to the main conclusion.

  20. Polarization of lanthanum nucleus by dynamic polarization method

    International Nuclear Information System (INIS)

    Adachi, Toshikazu; Ishimoto, Shigeru; Masuda, Yasuhiro; Morimoto, Kimio

    1989-01-01

    Preliminary studies have been carried out concerning the application of a dynamic polarization method to polarizing lanthanum fluoride single crystal to be employed as target in experiments with time reversal invariance. The present report briefly outlines the dynamic polarization method and describes some preliminary studies carried out so far. Dynamic polarization is of particular importance because no techniques are currently available that can produce highly polarized static nucleus. Spin interaction between electrons and protons (nuclei) plays a major role in the dynamic polarization method. In a thermal equilibrium state, electrons are polarized almost completely while most protons are not polarized. Positively polarized proton spin is produced by applying microwave to this system. The most hopeful candidate target material is single crystal of LaF 3 containing neodymium because the crystal is chemically stable and easy to handle. The spin direction is of great importance in experiments with time reversal invariance. The spin of neutrons in the target can be cancelled by adjusting the external magnetic field applied to a frozen polarized target. In a frozen spin state, the polarity decreases slowly with a relaxation time that depends on the external magnetic field and temperature. (N.K.)

  1. The Polar Rock Repository: Rescuing Polar Collections for New Research

    Science.gov (United States)

    Grunow, A.

    2016-12-01

    Geological field expeditions in polar regions are logistically difficult, financially expensive and can have a significant environmental impact on pristine regions. The scarcity of outcrop in Antarctica (98% ice-covered) makes previously collected rock samples very valuable to the science community. NSF recognized the need for preserving rock, dredge, and terrestrial core samples from polar areas and created the Polar Rock Repository (PRR). The PRR collection allows for full and open access to both samples and metadata via the PRR website. In addition to the physical samples and their basic metadata, the PRR archives supporting materials from the collector, field notebooks, images of the samples, field maps, air photos, thin sections and any associated bibliography/DOI's. Many of these supporting materials are unique. More than 40,000 samples are available from the PRR for scientific analysis to researchers around the globe. Most of the samples cataloged at the PRR were collected more than 30 years ago, some more than 100 years ago. The rock samples and metadata are made available online through an advanced search engine for the PRR website. This allows scientists to "drill down" into search results using categories and look-up object fields similar to websites like Amazon. Results can be viewed in a table, downloaded as a spreadsheet, or plotted on an interactive map that supports display of satellite imagery and bathymetry layers. Samples can be requested by placing them in the `shopping cart'. These old sample collections have been repeatedly used by scientists from around the world. One data request involved locating coal deposits in Antarctica for a global compilation and another for looking at the redox state of batholithic rocks from the Antarctic Peninsula using magnetic susceptibilities of PRR rocks. Sample usage has also included non-traditional geologic studies, such as a search for monopoles in Cenozoic volcanic samples, and remote sensing

  2. Polar bears, Ursus maritimus

    Science.gov (United States)

    Rode, Karyn D.; Stirling, Ian

    2017-01-01

    Polar bears are the largest of the eight species of bears found worldwide and are covered in a pigment-free fur giving them the appearance of being white. They are the most carnivorous of bear species consuming a high-fat diet, primarily of ice-associated seals and other marine mammals. They range throughout the circumpolar Arctic to the southernmost extent of seasonal pack ice.

  3. Polarized advanced fuel reactors

    International Nuclear Information System (INIS)

    Kulsrud, R.M.

    1987-07-01

    The d- 3 He reaction has the same spin dependence as the d-t reaction. It produces no neutrons, so that if the d-d reactivity could be reduced, it would lead to a neutron-lean reactor. The current understanding of the possible suppression of the d-d reactivity by spin polarization is discussed. The question as to whether a suppression is possible is still unresolved. Other advanced fuel reactions are briefly discussed. 11 refs

  4. Polish polar research (outline

    Directory of Open Access Journals (Sweden)

    Krzysztof Ludwik Birkenmajer

    2017-12-01

    Full Text Available The article describes Polish research and discoveries in the Arctic and the Antarctic since the 19th century. The author is a geologist and since 1956 has been engaged in scientific field research on Spitsbergen, Greenland and Antarctica (23 expeditions. For many years chairman of the Committee on Polar Research of the Polish Academy of Sciences, he is now its Honorary Chairman.

  5. South Polar Polygons

    Science.gov (United States)

    2005-01-01

    4 July 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a polgyon-cracked surface, into which deep, somewhat kidney-bean-shaped pits have formed. These are landscapes of the martian south polar residual cap. This view was captured during May 2005. Location near: 86.9oS, 5.1oW Image width: 1.5 km (0.9 mi) Illumination from: upper left Season Southern Spring

  6. Novel polar sedimentary porphyrins

    Science.gov (United States)

    Prowse, W. G.; Maxwell, J. R.

    1989-11-01

    Two polar nickel porphyrins in Messel oil shale are shown to be the C 32 and C 30 components IIIa,b. In the sample examined, component IIIa is by far the major porphyrin alcohol and is present in an abundance similar to that of the major nickel alkyl porphyrin. These primary alcohols, which do not appear to be artifacts, are structurally related to alkyl porphyrins reported previously in Serpiano oil shale.

  7. Polarization properties of linearly polarized parabolic scaling Bessel beams

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Mengwen; Zhao, Daomu, E-mail: zhaodaomu@yahoo.com

    2016-10-07

    The intensity profiles for the dominant polarization, cross polarization, and longitudinal components of modified parabolic scaling Bessel beams with linear polarization are investigated theoretically. The transverse intensity distributions of the three electric components are intimately connected to the topological charge. In particular, the intensity patterns of the cross polarization and longitudinal components near the apodization plane reflect the sign of the topological charge. - Highlights: • We investigated the polarization properties of modified parabolic scaling Bessel beams with linear polarization. • We studied the evolution of transverse intensity profiles for the three components of these beams. • The intensity patterns of the cross polarization and longitudinal components can reflect the sign of the topological charge.

  8. Ultrasonography X gamma radiography

    International Nuclear Information System (INIS)

    Mello Campos, A.M. de

    1989-01-01

    The accumulated experience in the last ten years of substitution to essays by gamma radiography to essay by ultrasonography, starting of the systematic comparison and tabulation of the results obtained by both essays applied in welding joints, in field, in steel pipelines of the SABESP. (V.R.B.)

  9. Gamma knife radiosurgery

    International Nuclear Information System (INIS)

    Kobayashi, Tatsuya; Mori, Yohsimasa; Kida, Yoshihisa

    2003-01-01

    Gamma knife radiosurgery has become a new treatment modality in the field of neurosurgery since the first gamma knife was brought into Japan in 1990. Advances in applications of new indications and long-term results have been continued to evolve during the past 12 years. Based on the experience of more than 4,500 cases treated by gamma knife at Komaki City Hospital, long-term results of arteriovenous malformations (AVMs), metastatic brain tumors, acoustic neurinomas, meningiomas and trigeminal neuralgias are presented. Radiosurgery has become a novel treatment modality, especially for AVM, acoustic neurinoma and meningioma, which were once only treatable by conventional surgery, and shows a high cure rate in AVM cases and high control rate in benign tumors without major complications. The effects of radiosurgery for metastatic brain tumors have been thought to be superior to fractionated radiotherapy due to high response and control rates, and patients showed improved quality of life although no prolongation of the life span was obtained. Gamma knife treatment for trigeminal neuralgia has been shown to be effective and less invasive than microvascular decompression, and is useful for cases resistant to conventional therapies and as an initial treatment as well. (author)

  10. Automated gamma counters

    International Nuclear Information System (INIS)

    Regener, M.

    1977-01-01

    This is a report on the most recent developments in the full automation of gamma counting in RIA, in particular by Messrs. Kontron. The development targets were flexibility in sample capacity and shape of test tubes, the possibility of using different radioisotopes for labelling due to an optimisation of the detector system and the use of microprocessers to substitute software for hardware. (ORU) [de

  11. Gamma cardio 82

    International Nuclear Information System (INIS)

    Itti, R.

    1982-01-01

    New trends in nuclear cardiology are briefly presented supported by a large bibliography. The following topics are reviewed: new tracers of myocardial perfusion and metabolism; quantitative analysis of cardiac function; nuclear stethoscope; gamma emission tomography; diagnostic value of cardiac dynamic tests (at rest and during exercise), pharmacological tests; new clinical applications of cardiovascular nuclear medicine [fr

  12. Marine gamma spectrometric survey

    International Nuclear Information System (INIS)

    Kostoglodov, V.V.

    1979-01-01

    Presented are theoretical problems physical and geochemical prerequisites and possibilities of practical application of the method of continuous submarine gamma-spectrometric survey and radiometric survey destined for rapid study of the surface layer of marine sediments. Shown is high efficiency and advantages of this method in comparison with traditional and widely spread in marine geology methods of bottom sediments investigation

  13. Industrial radiography. Gamma radiography

    International Nuclear Information System (INIS)

    Menetrier, J.

    1975-01-01

    Informations are given on gamma radiodefectology regulations, entire references and main dispositions applicable to each state of the European Economic Community. The content includes previous arrangements for source acquisition, holding and use of the sources, transport, accidents, civil liability of the source holder, person insurance against radiation hazards and contamination, property insurance, penal liability of the source holder

  14. Introscopy using gamma sources

    International Nuclear Information System (INIS)

    Gromov, Yu.V.; Leonov, B.I.; Najorov, A.N.; Smirnov, N.N.; Firstov, V.G.

    1978-01-01

    A method is described of working with standard 170 Tm, 75 Se, 192 Ir, 137 Cs and 60 Co sources at the activity of 1-4000 Ci, during television gamma introscopy of steel products. Experiments involving the RI-10T introscope are carried out to determine prospects of using various radiation sources. The results of using X-ray instruments for control of steel products are also shown for comparison. In introscopy of X-rayed steel products over 25 mm thick, spreading of the edge of the detected groove image is shown to be comparable when using X radiation and gamma radiation of standard sources. Sensitivity of control by fluorographic introscope in X-raying and gamma irradiation of products over 25 mm thick will presumably be the same owing to the detector storage capacity. The use of commercial gamma flaw detecting instruments together with a television introscope permits to reliably reveal defects of 0.5-2.0 mm in size, eliminating possible instability of operation of X-ray instruments, particularly in field conditions

  15. Gamma apparatuses for radiotherapy

    International Nuclear Information System (INIS)

    Sul'kin, A.G.

    1986-01-01

    Scientific and technical achievements in development and application of gamma therapeutic apparatuses for external and intracavity irradiations are generalized. Radiation-physical parameters of apparatuses providing usability of progressive methods in radiotherapy of onclogical patients are given. Optimization of main apparatus elements, ensurance of its operation reliability, reduction of errors of irradiation plan reproduction are considered. Attention is paid to radiation safety

  16. Gamma ray calibration system

    International Nuclear Information System (INIS)

    Rosauer, P.J.; Flaherty, J.J.

    1981-01-01

    This invention is in the field of gamma ray inspection devices for tubular products and the like employing an improved calibrating block which prevents the sensing system from being overloaded when no tubular product is present, and also provides the operator with a means for visually detecting the presence of wall thicknesses which are less than a required minimum. (author)

  17. Prospects of polarized fixed target Drell-Yan experiments

    International Nuclear Information System (INIS)

    Liu, M X; Jiang, X; Crabb, D G; Chen, J P; Bai, M

    2011-01-01

    It has been proposed that the Siverse transverse single spin asymmetry in Drell-Yan production in transversely polarized p+p collisions would have an opposite sign compared to what has been observed in the polarized Semi-Inclusive Deep Inelastic Scattering (SIDIS) experiments. Experimental confirmation or disproval of this prediction would provide a novel fundamental test of QCD and shed new light on our theoretical understanding of the transverse spin physics phenomena. We discuss the prospects and physics sensitivities of polarized fixed target Drell-Yan experiments that could utilize the existing proton and other hadron beams at Fermilab, and polarized proton beams at RHIC with a polarized solid proton and/or neutron target option. We show that if realized, the new experiments would provide critical measurements of not only the sign change (or not) of Sivers functions, but also the information of quark and antiquark's Sivers distributions over a wide kinematic range.

  18. Polarization Studies for the eRHIC Electron Storage Ring

    Energy Technology Data Exchange (ETDEWEB)

    Gianfelice-Wendt, Eliana [Fermilab; Tepikian, S. [Brookhaven

    2018-04-01

    A hadron/lepton collider with polarized beams has been under consideration by the scientific community since some years, in the U.S. and Europe. Among the various proposals, those by JLAB and BNL with polarized electron and proton beams are currently under closer study in the U.S. Experimenters call for the simultaneous storage of electron bunches with both spin helicity. In the BNL based Ring-Ring design, electrons are stored at top energy in a ring to be accommodated in the existing RHIC tunnel. The transversely polarized electron beam is injected into the storage ring at variable energies, between 5 and 18 GeV. Polarization is brought into the longitudinal direction at the IP by a couple of spin rotators. In this paper results of first studies of the attainable beam polarization level and lifetime in the storage ring at 18 GeV are presented.

  19. Generation of valley-polarized electron beam in bilayer graphene

    International Nuclear Information System (INIS)

    Park, Changsoo

    2015-01-01

    We propose a method to produce valley-polarized electron beams using a bilayer graphene npn junction. By analyzing the transmission properties of electrons through the junction with zigzag interface in the presence of trigonal warping, we observe that there exist a range of incident energies and barrier heights in which transmitted electrons are well polarized and collimated. From this observation and by performing numerical simulations, it is demonstrated that valley-dependent electronic currents with nearly perfect polarization can be generated. We also show that the peak-to-peak separation angle between the polarized currents is tunable either by incident energy or by barrier height each of which is controlled by using top and back gate voltages. The results can be used for constructing an electron beam splitter to produce valley-polarized currents

  20. Generation of valley-polarized electron beam in bilayer graphene

    Science.gov (United States)

    Park, Changsoo

    2015-12-01

    We propose a method to produce valley-polarized electron beams using a bilayer graphene npn junction. By analyzing the transmission properties of electrons through the junction with zigzag interface in the presence of trigonal warping, we observe that there exist a range of incident energies and barrier heights in which transmitted electrons are well polarized and collimated. From this observation and by performing numerical simulations, it is demonstrated that valley-dependent electronic currents with nearly perfect polarization can be generated. We also show that the peak-to-peak separation angle between the polarized currents is tunable either by incident energy or by barrier height each of which is controlled by using top and back gate voltages. The results can be used for constructing an electron beam splitter to produce valley-polarized currents.

  1. Wavelet analysis of polarization maps of polycrystalline biological fluids networks

    Science.gov (United States)

    Ushenko, Y. A.

    2011-12-01

    The optical model of human joints synovial fluid is proposed. The statistic (statistic moments), correlation (autocorrelation function) and self-similar (Log-Log dependencies of power spectrum) structure of polarization two-dimensional distributions (polarization maps) of synovial fluid has been analyzed. It has been shown that differentiation of polarization maps of joint synovial fluid with different physiological state samples is expected of scale-discriminative analysis. To mark out of small-scale domain structure of synovial fluid polarization maps, the wavelet analysis has been used. The set of parameters, which characterize statistic, correlation and self-similar structure of wavelet coefficients' distributions of different scales of polarization domains for diagnostics and differentiation of polycrystalline network transformation connected with the pathological processes, has been determined.

  2. Polarized Photocathode R&D for Future Linear Collliders

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, F; Brachmann, A.; Maruyama, T.; Sheppard, J.C.; /SLAC

    2009-01-23

    It is a challenge to generate full charge electrons from the electron sources without compromising polarization for the proposed ILC and CLIC. It is essential to advance polarized photocathodes to meet the requirements. SLAC has worldwide unique dedicated test facilities, Cathode Test System and dc-Gun Test Laboratory, to fully characterize polarized photocathodes. Recent systematic measurements on a strained-well InAlGaAs/AlGaAs cathode at the facilities show that 87% polarization and 0.3% QE are achieved. The QE can be increased to {approx}1.0% with atomic hydrogen cleaning. The surface charge limit at a very low current intensity and the clear dependence of the polarization on the surface charge limit are observed for the first time. On-going programs to develop photocathodes for the ILC and CLIC are briefly introduced.

  3. Persistence of the Polarization in a Fusion Process

    Directory of Open Access Journals (Sweden)

    Deutsch C.

    2010-04-01

    Full Text Available We propose an experiment to test the persistence of the polarization in a fusion process, using a petawatt laser hitting a polarized HD target. The polarized protons and deuterons heated in the plasma induced by the laser have a significant probability to fuse producing a 3He and a γ ray or a neutron in the final state. The angular distribution of the radiated γ rays and the change in the correponding total cross section are related to the polarization persistence, but the resulting signal turns out to be weak. By comparison, the neutrons are produced hadronically with a larger cross section and are much easier to detect experimentally. A significant reduction of the cross section by parallel polarization of the deuterons is reliably predicted by the theory. Therefore, it is expected that the corresponding signal on the neutron counting rate could be seen experimentally.

  4. Demonstration of a collimated in situ method for determining depth distributions using gamma-ray spectrometry

    CERN Document Server

    Benke, R R

    2002-01-01

    In situ gamma-ray spectrometry uses a portable detector to quantify radionuclides in materials. The main shortcoming of in situ gamma-ray spectrometry has been its inability to determine radionuclide depth distributions. Novel collimator designs were paired with a commercial in situ gamma-ray spectrometry system to overcome this limitation for large area sources. Positioned with their axes normal to the material surface, the cylindrically symmetric collimators limited the detection of un attenuated gamma-rays from a selected range of polar angles (measured off the detector axis). Although this approach does not alleviate the need for some knowledge of the gamma-ray attenuation characteristics of the materials being measured, the collimation method presented in this paper represents an absolute method that determines the depth distribution as a histogram, while other in situ methods require a priori knowledge of the depth distribution shape. Other advantages over previous in situ methods are that this method d...

  5. An improved in situ method for determining depth distributions of gamma-ray emitting radionuclides

    International Nuclear Information System (INIS)

    Benke, R.R.; Kearfott, K.J.

    2001-01-01

    In situ gamma-ray spectrometry determines the quantities of radionuclides in some medium with a portable detector. The main limitation of in situ gamma-ray spectrometry lies in determining the depth distribution of radionuclides. This limitation is addressed by developing an improved in situ method for determining the depth distributions of gamma-ray emitting radionuclides in large area sources. This paper implements a unique collimator design with conventional radiation detection equipment. Cylindrically symmetric collimators were fabricated to allow only those gamma-rays emitted from a selected range of polar angles (measured off the detector axis) to be detected. Positioned with its axis normal to surface of the media, each collimator enables the detection of gamma-rays emitted from a different range of polar angles and preferential depths. Previous in situ methods require a priori knowledge of the depth distribution shape. However, the absolute method presented in this paper determines the depth distribution as a histogram and does not rely on such assumptions. Other advantages over previous in situ methods are that this method only requires a single gamma-ray emission, provides more detailed depth information, and offers a superior ability for characterizing complex depth distributions. Collimated spectrometer measurements of buried area sources demonstrated the ability of the method to yield accurate depth information. Based on the results of actual measurements, this method increases the potential of in situ gamma-ray spectrometry as an independent characterization tool in situations with unknown radionuclide depth distributions

  6. Applications of polarized neutrons

    International Nuclear Information System (INIS)

    Mezei, F.

    1993-01-01

    The additional spin degree of freedom of the neutron can be made use of in neutron scattering work in two fundamental ways: (a) directly for the identification of magnetic scattering effects and (b) indirectly as a spectroscopic tool for modulating and analysing beams. Although strong magnetic scattering contributions can often be studied by unpolarized neutrons, a fully unambiguous separation of nuclear and magnetic phenomena can only be achieved by the additional information provided by polarized neutrons, especially if one of the two kinds of contributions is weak compared to the other. In the most general case a sample with both magnetic and nuclear features can be characterized by as many as 16 independent dynamic correlation functions instead of the single well known S(q, ω) for non-magnetic nuclear scattering only. Polarization analysis in principle allows one to determine all these 16 functions. The indirect applications of polarized neutrons are also steadily gaining importance. The most widely used method of this kind, the application of Larmor precessions for high resolution energy analysis in Neutron Spin Echo spectroscopy opened up a whole new domain in inelastic neutron scattering which was not accessible to any other spectroscopic method with or without neutrons before. (author)

  7. Pliocene geomagnetic polarity epochs

    Science.gov (United States)

    Dalrymple, G.B.; Cox, A.; Doell, Richard R.; Gromme, C.S.

    1967-01-01

    A paleomagnetic and K-Ar dating study of 44 upper Miocene and Pliocene volcanic units from the western United States suggests that the frequency of reversals of the earth's magnetic field during Pliocene time may have been comparable with that of the last 3.6 m.y. Although the data are too limited to permit the formal naming of any new polarity epochs or events, four polarity transitions have been identified: the W10 R/N boundary at 3.7 ?? 0.1 m.y., the A12 N/R boundary at 4.9 ?? 0.1 m.y., the W32 N/R boundary at 9.0 ?? 0.2m.y., and the W36 R/N boundary at 10.8 ?? 0.3 - 1.0 m.y. The loss of absolute resolution of K-Ar dating in older rocks indicates that the use of well defined stratigraphic successions to identify and date polarity transitions will be important in the study of Pliocene and older reversals. ?? 1967.

  8. Calibration of nuclides by gamma-gamma sum peak coincidence counting

    International Nuclear Information System (INIS)

    Guevara, E.A.

    1986-01-01

    The feasibility of extending sum peak coincidence counting to the direct calibration of gamma-ray emitters having particular decay schemes was investigated, also checkings of the measurement accuracy, by comparing with more precise beta-gamma coincidence counting have been performed. New theoretical studies and experiments were developed, demonstrating the reliability of the procedure. Uncertainties of less than one percent were obtained when certain radioactive sources were measured. The application of the procedure to 60 Co, 22 Na, 47 Ca and 148 Pm was studied. Theoretical bases of sum peak coincidence counting were set in order to extend it as an alternative method for absolute activity determination. In this respect, theoretical studies were performed for positive and negative beta decay, and electron capture, either accompanied or unaccompanied by coincident gamma rays. They include decay schemes containing up to three daughter nuclide excited levels, for different geometrical configurations. Equations are proposed for a possible generalization of the procedure. (M.E.L.) [es

  9. Towards helium-3 neutron polarizers

    International Nuclear Information System (INIS)

    Tasset, F.

    1995-01-01

    With a large absorption cross-section entirely due to antiparallel spin capture, polarized helium-3 is presently the most promising broad-band polarizer for thermal and epithermal neutrons. Immediate interest was raised amongst the neutron community when a dense gaseous 3 He polarizer was used for the first time in 1988, on a pulsed neutron beam at Los Alamos. With 20 W of laser power on a 30 cm long, 8.6 atm target, 40% 3 He polarization was achieved in a recent polarized electron scattering experiment at SLAC. In this technique the 3 He nuclei are polarized directly at an appropriate high pressure through spin-exchange collisions with a thick, optically pumped rubidium vapor. A different and competitive approach is being presently developed at Mainz University in collaboration with ENS Paris and now the ILL. A discharge is established in pure 3 He at low pressure producing excited metastable atoms which can be optically pumped with infra-red light. Highly effective exchange collision with the atoms remaining in the ground state quickly produces 75% polarization at 1.5 mbar. A truly non-magnetic system then compresses the polarized gas up to several bars as required. The most recent machine comprises a two-stage glass-titanium compressor. In less than 1 h it can inflate a 100 cm 3 target cell with three bars of polarized gas. The very long relaxation times (several days) now being obtained at high pressure with a special metallic coating on the glass walls, the polarized cell can be detached and inserted in the neutron beam as polarizer. We expect 50% 3 He-polarization to be reached soon, allowing such filters to compete favorably with existing Heusler-crystal polarizers at thermal and short neutron wavelengths. It must be stressed that such a system based on a 3 He polarization factory able to feed several passive, transportable, polarizers is well matched to neutron scattering needs. (orig.)

  10. Deep inelastic scattering of polarized electrons by polarized {sup 3} He and the study of the neutron spin structure

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, R G; Bosted, P E; Dunne, J; Fellbaum, J; Keppel, C; Rock, S E; Spengos, M; Szalata, Z M; White, J L [Washington State Univ., Pullman, WA (United States); Breton, V; Fonvieille, H; Roblin, Y [Clermont-Ferrand-2 Univ., 63 - Aubiere (France); Shapiro, G [Lawrence Berkeley Lab., CA (United States); Hughes, E W [California Inst. of Tech., Pasadena, CA (United States); Borel, H; Lombard-Nelsen, R M; Marroncle, J; Morgenstern, J; Staley, F; Terrien, Y [CEA Centre d` Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. d` Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l` Instrumentation Associee; Petratos, G G [Kent State Univ., OH (United States); Anthony, P L; Dietrich, F S [Lawrence Livermore National Lab., CA (United States); Chupp, T E; Smith, T [Michigan Univ., Dearborn, MI (United States); Thompson, A K [National Inst. of Standards and Technology, Gaithersburg, MD (United States); Kuhn, S E [Norfolk State Univ., VA (United States); Cates, G D; Middleton, H; Newbury, N R [Princeton Univ., NJ (United States); Anthony, P L; Gearhart, R; Hughes, E W; Maruyama, T; Meyer, W; Petratos, G G; Pitthan, R; Rokni, S H; Stuart, L M; White, J L; Woods, M; Young, C C [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Erbacher, R; Kawall, D; Kuhn, S E; Meziani, Z E [Stanford Univ., CA (United States); Holmes, R; Souder, P A; Xu, J [Syracuse Univ., NY (United States); Meziani, Z E [Temple Univ., Philadelphia, PA (United States); Band, H R; Johnson, J R; Maruyama, T; Prepost, R; Zapala, G [Wisconsin Univ., Madison, WI (United States)

    1997-12-31

    The neutron longitudinal and transverse asymmetries A{sub 1}{sup n} and A{sub 2}{sup n} have been extracted from deep inelastic scattering of polarized electrons by a polarized {sup 3}He target at incident energies of 19.42, 22.66 and 25.51 GeV. The measurement allows for the determination of the neutron spin structure functions g{sub 1}{sup n}(x, Q{sup 2}) and g{sub 2}{sup n} (x, Q{sup 2}) over the range 0.03 < x < 0.6 at an average Q{sup 2} of 2 (GeV/c){sup 2}. The data are used for the evaluation of the Ellis-Jaffe and Bjorken sum rules. The neutron spin structure function g{sub 1}{sup n} (x, Q{sup 2}) is small and negative within the range of our measurement, yielding an integral {integral}{sub 0.03}{sup 0.6} g{sub 1}{sup n} (x)dx - 0.028 {+-} 0.006 (stat) {+-} 0.006 (syst). Assuming Regge behavior at low x, we extract {Gamma}{sub 1}{sup n} {integral}{sub 0}{sup 1} g{sub 1}{sup n} (x)dx = - 0.031 {+-} 0.006 (stat) {+-} 0.009 (syst). Combined with previous proton integral results from SLAC experiment E143, we find {Gamma}{sub 1}{sup p} - {Gamma}{sub 1}{sup n} = 0.160 {+-} 0.015 in agreement with the Bjorken sum rule prediction {Gamma}{sub 1}{sup p} - {Gamma}{sub 1}{sup p} 0.176 {+-} 0.008 at a Q{sup 2} value of 3 (GeV/c){sup 2} evaluated using {alpha}{sub s} 0.32 {+-} 0.05. (authors). 109 refs.

  11. Black Hole Accretion in Gamma Ray Bursts

    Directory of Open Access Journals (Sweden)

    Agnieszka Janiuk

    2017-02-01

    Full Text Available We study the structure and evolution of the hyperaccreting disks and outflows in the gamma ray bursts central engines. The torus around a stellar mass black hole is composed of free nucleons, Helium, electron-positron pairs, and is cooled by neutrino emission. Accretion of matter powers the relativistic jets, responsible for the gamma ray prompt emission. The significant number density of neutrons in the disk and outflowing material will cause subsequent formation of heavier nuclei. We study the process of nucleosynthesis and its possible observational consequences. We also apply our scenario to the recent observation of the gravitational wave signal, detected on 14 September 2015 by the two Advanced LIGO detectors, and related to an inspiral and merger of a binary black hole system. A gamma ray burst that could possibly be related with the GW150914 event was observed by the Fermi satellite. It had a duration of about 1 s and appeared about 0.4 s after the gravitational-wave signal. We propose that a collapsing massive star and a black hole in a close binary could lead to the event. The gamma ray burst was powered by a weak neutrino flux produced in the star remnant’s matter. Low spin and kick velocity of the merged black hole are reproduced in our simulations. Coincident gravitational-wave emission originates from the merger of the collapsed core and the companion black hole.

  12. Design innovations in neutron and gamma detectors

    International Nuclear Information System (INIS)

    Prasad, K.R.

    2003-01-01

    Neutron and gamma radiation needs to be monitored in most nuclear installations since it is highly penetrating. On-line monitoring of these radiations is very important for the safe and controlled operation of nuclear reactors, accelerators etc. Several design innovations have been carried out on gas ionisation detectors such as boron-lined proportional counters and ion chambers, fission detectors, gamma ion chambers as well as self-powered detectors. The use of additional structures within boron-lined detectors has enhanced their neutron sensitivity without a corresponding increase in the unwanted gamma sensitivity. The neutron sensitivity of fission counters can be enhanced by designing them as transmission line devices. Ion chambers with two and six pairs of electrodes have been developed for monitoring pulsed x-ray background at accelerator areas. Ion chambers have been employed at gamma fields up to 80 kR/h by deriving the exposure levels on-line using microcontroller devices programmed on the basis of theoretical and empirical formulas. The use of gas electron multiplier foils is proposed for charge multiplication in ion chambers. Self-powered detectors with new emitter materials like Hi, Ni and Inconel have been developed. (author)

  13. Polar lunar power ring: Propulsion energy resource

    Science.gov (United States)

    Galloway, Graham Scott

    1990-01-01

    A ring shaped grid of photovoltaic solar collectors encircling a lunar pole at 80 to 85 degrees latitude is proposed as the primary research, development, and construction goal for an initial lunar base. The polar Lunar Power Ring (LPR) is designed to provide continuous electrical power in ever increasing amounts as collectors are added to the ring grid. The LPR can provide electricity for any purpose indefinitely, barring a meteor strike. The associated rail infrastructure and inherently expandable power levels place the LPR as an ideal tool to power an innovative propulsion research facility or a trans-Jovian fleet. The proposed initial output range is 90 Mw to 90 Gw.

  14. Mechanism of anterior-posterior polarity control in planarians

    Energy Technology Data Exchange (ETDEWEB)

    Lange, C.S.; Steele, V.E.

    1978-01-01

    The substance which inhibits brain formation in the regenerating planarian Dugesia etrusca was found to be a large molecule, at least in part protein, which electrophoreses as an electronegative moiety in pH 6.8 buffer. A model is presented, based on this finding and previous studies, which proposes an electrochemical mechanism for the control of polarity and possibly for the maintenance of tissue organization in planarians. It is proposed that a bioelectric field exists and moves the electronegative brain-inhibiting substance in a posterior direction, establishing polarity. This model explains the polarity reversal experiments using external fields and many of the previously unexplained classical planarian experiments. Data are presented demonstrating the existence, magnitude, and polarity of this bioelectric field, which is not greatly altered upon decapitation, all in accord with predictions of the model.

  15. Polarization speckles and generalized Stokes vector wave: a review [invited

    DEFF Research Database (Denmark)

    Takeda, Mitsuo; Wang, Wei; Hanson, Steen Grüner

    2010-01-01

    We review some of the statistical properties of polarization-related speckle phenomena, with an introduction of a less known concept of polarization speckles and their spatial degree of polarization. As a useful means to characterize twopoint vector field correlations, we review the generalized...... Stokes parameters proposed by Korotkova and Wolf, and introduce its time-domain representation to describe the space-time evolution of the correlation between random electric vector fields at two different space-time points. This time-domain generalized Stokes vector, with components similar to those...... of the beam coherence polarization matrix proposed by Gori, is shown to obey the wave equation in exact analogy to a coherence function of scalar fields. Because of this wave nature, the time-domain generalized Stokes vector is referred to as generalized Stokes vector wave in this paper....

  16. Review of polarized ammonium target

    International Nuclear Information System (INIS)

    Matsuda, Tatsuo

    1987-01-01

    Recently, ammonia (NH 3 ) and deutron ammonia (ND 3 ), instead of conventional alcohol substances, have been used more frequently as a polarized target substance for experiments of polarization at high energy regions. This article reviews major features of the polarized (deutron) ammonia targets. The dynamic nuclear polarization (DNT) method is widely used in high energy polarization experiments. While only a low polarization degree of hydrogen nucleus of 1.7 percent can be obtained by the Brute force method, DNP can produce polarization as high as ∼ 90 percent (2.5 T, ∼ 200 mK). In 1979, ammonia was irradiated with radiations to form NH 2 free radicals, resulting in the achievement of a high polarization degree of greater than 90 percent (hydrogen). Since then, ammonia and deutron ammonia have increasingly been replacing alcohols including butanol. Irradiation of a target substance with radiations destroys the structure of the substance, leading to a decrease in polarization degree. However, ammonia produces unpaired electrons as a result of irradiation, allowing it to be highly resistant to radiation. This report also present some study results, including observations on effects of radiation on the polarization degree of a target, effects of annealing, and polarization of 14 N. A process for producing an ammonia target is also described. (Nogami, K.)

  17. Polarization: A must for fusion

    Directory of Open Access Journals (Sweden)

    Didelez J.-P.

    2013-11-01

    Full Text Available The complete polarization of DT fuel would increase the fusion reactivity by 50% in magnetic as well as in inertial confinements. The persistence of polarization in a fusion process could be tested, using a terawatt laser hitting a polarized HD target. The polarized deuterons heated in the plasma induced by the laser can fuse producing a 3He and a neutron in the final state. The angular distribution of the emitted neutrons and the change in the corresponding total Cross Section (CS can sign the polarization persistence. The polarization of solid H2, D2 or T2 Hydrogen isotopes is very difficult. However, it has been possible to polarize HD, a hetero-molecular form of Hydrogen, by static polarization, at very low temperature and very high field. The radioactivity of DT molecules forbids there high polarization by the static method, therefore one has to develop the Dynamic Nuclear Polarization (DNP by RF transitions. The DNP of HD has been investigated in the past. The magnetic properties of HD and DT molecules are very similar, it is therefore expected that any polarization result obtained with HD could be extrapolated to DT.

  18. gamma-Glutamyl amino acids. Transport and conversion to 5-oxoproline in the kidney

    International Nuclear Information System (INIS)

    Bridges, R.J.; Meister, A.

    1985-01-01

    Transport of gamma-glutamyl amino acids, a step in the proposed glutathione-gamma-glutamyl transpeptidase-mediated amino acid transport pathway, was examined in mouse kidney. The transport of gamma-glutamyl amino acids was demonstrated in vitro in studies on kidney slices. Transport was followed by measuring uptake of 35 S after incubation of the slices in media containing gamma-glutamyl methionine [ 35 S]sulfone. The experimental complication associated with extracellular conversion of the gamma-glutamyl amino acid to amino acid and uptake of the latter by slices was overcome by using 5-oxoproline formation (catalyzed by intracellular gamma-glutamyl-cyclotransferase) as an indicator of gamma-glutamyl amino acid transport. This method was also successfully applied to studies on transport of gamma-glutamyl amino acids in vivo. Transport of gamma-glutamyl amino acids in vitro and in vivo is inhibited by several inhibitors of gamma-glutamyl transpeptidase and also by high extracellular levels of glutathione. This seems to explain urinary excretion of gamma-glutamylcystine by humans with gamma-glutamyl transpeptidase deficiency and by mice treated with inhibitors of this enzyme. Mice depleted of glutathione by treatment with buthionine sulfoximine (which inhibits glutathione synthesis) or by treatment with 2,6-dimethyl-2,5-heptadiene-4-one (which effectively interacts with tissue glutathione) exhibited significantly less transport of gamma-glutamyl amino acids than did untreated controls. The findings suggest that intracellular glutathione functions in transport of gamma-glutamyl amino acids. Evidence was also obtained for transport of gamma-glutamyl gamma-glutamylphenylalanine into kidney slices

  19. Elite Polarization and Public Opinion

    DEFF Research Database (Denmark)

    Robison, Joshua; Mullinix, Kevin

    2016-01-01

    Elite polarization has reshaped American politics and is an increasingly salient aspect of news coverage within the United States. As a consequence, a burgeoning body of research attempts to unravel the effects of elite polarization on the mass public. However, we know very little about how...... polarization is communicated to the public by news media. We report the results of one of the first content analyses to delve into the nature of news coverage of elite polarization. We show that such coverage is predominantly critical of polarization. Moreover, we show that unlike coverage of politics focused...... on individual politicians, coverage of elite polarization principally frames partisan divisions as rooted in the values of the parties rather than strategic concerns. We build on these novel findings with two survey experiments exploring the influence of these features of polarization news coverage on public...

  20. The polarization of fast neutrons

    International Nuclear Information System (INIS)

    Talov, V.V.

    2001-01-01

    It is insufficient to know coordinates and momentum to describe a state of a neutron. It is necessary to define a spin orientation. As far as it is known from quantum mechanics, a half spin has a projection in the positive direction or in the negative direction. The probability of both projections in an unpolarized beam is equal. If a direction exists, in which the projection is more probably then beam is called polarized in this direction. It is essential to know polarization of neutrons for characteristics of a neutron source, which is emitting it. The question of polarization of fast neutrons came up in 50's. The present work is the review of polarization of fast neutrons and methods of polarization analysis. This also includes information about polarization of fast neutrons from first papers, which described polarization in the D(d,n) 3 He, 7 Li (p,n) 7 Be, T(p,n) 3 He reactions. (authors)